{"$schema":"nativecad-dfm-pack/1","id":"battery-systems","title":"Battery systems: cells, joining, modules, packs, HV safety, tests and motorsport ES","sector":"battery-systems","version":"2026-11-04","summary":"How high-performance lithium-ion systems are made and what that demands of the CAD: cell envelopes and swelling, tab and busbar joining, holders and end plates, cold plates, runaway barriers, HV spacing, UN 38.3 and R100 tests, and FIA, Formula E, WEC and Formula Student rules, each with its year.","aliases":["battery","battery pack","battery module","lithium ion","li-ion","cell holder","busbar","bms","thermal runaway","18650","21700","4680","pouch cell","prismatic cell","energy store","ers battery","tab welding","cold plate","accumulator"],"crossSector":false,"size":"standard","sources":[{"id":"fia-2026-c21","title":"FIA 2026 F1 Regulations, Section C Technical, Issue 21 (2026-10-19)","accessed":"2026-11-04","url":"https://www.fia.com/system/files/documents/fia_2026_f1_regulations_-_section_c_technical_-_iss_21_-_2026-10-19.pdf","note":"PDF scrambles sub-article numbers; wording read from the text."},{"id":"fs-rules-2026","title":"Formula Student Rules 2026 v1.0 (Formula Student Germany)","accessed":"2026-11-04","url":"https://www.formulastudent.de/fileadmin/user_upload/all/2026/rules/FS-Rules_2026_v1.0.pdf"},{"id":"jsae-ev-2026","title":"JSAE 2026 EV Design Guide v2 (Formula SAE based; renames accumulator container to TBC, segment to module)","accessed":"2026-11-04","url":"https://preopening.jsae.or.jp/files_publish/page/525/2026_EV_DesignGuide_ver2.pdf"},{"id":"un-r100-02","title":"UN Regulation No. 100, 02 series, MLIT copy (annexes 8A to 8I read)","accessed":"2026-11-04","url":"https://www.mlit.go.jp/jidosha/un/UN_R100.pdf","note":"Older series; 05 series entered into force 2025-09-26 and changes propagation requirements."},{"id":"fmvss-305","title":"49 CFR 571.305 FMVSS 305 Electric-powered vehicles","accessed":"2026-11-04","url":"https://www.law.cornell.edu/cfr/text/49/571.305"},{"id":"un383-report","title":"UN 38.3 test report quoting ST/SG/AC.10/11/Rev.7 section 38.3 verbatim (Toyota BTO-074B pack)","accessed":"2026-11-04","url":"https://toyota.jp/pages/contents/cwalks/aircraft/pdf/rep_un_38_3_bto_074b.pdf","note":"UN Manual fetch refused; this report restates it. Check current revision."},{"id":"samsung-50e","title":"Samsung SDI INR21700-50E cell specification V1.0","accessed":"2026-11-04","url":"https://shop.aceongroup.com/cdn/shop/files/RLII-CSI-1618_Samsung_50E_DATASHEET.pdf"},{"id":"molicel-p42a","title":"Molicel INR-21700-P42A product data sheet","accessed":"2026-11-04","url":"https://www.rcscomponents.kiev.ua/datasheets/INR21700P42A-V4-80092.pdf"},{"id":"sony-vtc6","title":"Sony US18650VTC6 technical information rev 0.1 (2015)","accessed":"2026-11-04","url":"https://www.kronium.cz/uploads/SONY_US18650VTC6.pdf"},{"id":"bd-4680","title":"Battery Design: Tesla 4680 cell benchmark (UCSD LESC and teardown data)","accessed":"2026-11-04","url":"https://www.batterydesign.net/tesla-4680-cell/"},{"id":"bd-vda","title":"Battery Design: VDA prismatic cells","accessed":"2026-11-04","url":"https://www.batterydesign.net/vda-prismatic-cells/"},{"id":"bd-expansion","title":"Battery Design: cell electrode pressure and expansion","accessed":"2026-11-04","url":"https://www.batterydesign.net/battery-cell/cell-electrode-pressure-and-expansion/"},{"id":"bd-module","title":"Battery Design: battery module design","accessed":"2026-11-04","url":"https://www.batterydesign.net/module/"},{"id":"bd-ctp-ratio","title":"Battery Design: cell to pack mass ratio","accessed":"2026-11-04","url":"https://www.batterydesign.net/cell-to-pack-mass-ratio/"},{"id":"bd-ctp-chem","title":"Battery Design: cell to pack mass ratio by chemistry and format","accessed":"2026-11-04","url":"https://www.batterydesign.net/cell-to-pack-mass-ratio-by-chemistry-and-format/"},{"id":"bd-busbars","title":"Battery Design: busbars","accessed":"2026-11-04","url":"https://www.batterydesign.net/electrical/high-voltage-system/busbars/"},{"id":"bd-venting","title":"Battery Design: venting","accessed":"2026-11-04","url":"https://www.batterydesign.net/safety/venting/"},{"id":"bd-runaway","title":"Battery Design: thermal runaway","accessed":"2026-11-04","url":"https://www.batterydesign.net/safety/thermal-runaway/"},{"id":"bd-mica","title":"Battery Design: mica","accessed":"2026-11-04","url":"https://www.batterydesign.net/materials/mica/"},{"id":"bd-creepage","title":"Battery Design: creepage and clearance","accessed":"2026-11-04","url":"https://www.batterydesign.net/electrical/creepage-and-clearance/"},{"id":"bd-gb38031","title":"Battery Design: GB 38031 summary","accessed":"2026-11-04","url":"https://www.batterydesign.net/legislation-rules-and-regulations/gb38031/"},{"id":"bd-r100","title":"Battery Design: UN Regulation 100 summary","accessed":"2026-11-04","url":"https://www.batterydesign.net/legislation-rules-and-regulations/un-regulation-100/"},{"id":"bd-pouch-cooling","title":"Battery Design: pouch cell cooling (summarising Hunt et al., J. Electrochem. Soc. 163(9), 2016)","accessed":"2026-11-04","url":"https://www.batterydesign.net/pouch-cell-cooling/"},{"id":"bd-pressure-map","title":"Battery Design: mapping pouch cell pressure distribution in operando","accessed":"2026-11-04","url":"https://www.batterydesign.net/mapping-pouch-cell-pressure-distribution-in-operando/"},{"id":"bd-f1","title":"Battery Design: Formula 1 battery rules (history by year, Scarborough on cooling)","accessed":"2026-11-04","url":"https://www.batterydesign.net/formula-1-battery-rules/"},{"id":"das-2018","title":"Das, Li, Williams, Greenwood: Joining technologies for automotive battery systems manufacturing, World Electric Vehicle J. 9(2), 2018 (CC BY)","accessed":"2026-11-04","url":"https://wrap.warwick.ac.uk/id/eprint/93286/13/WRAP-joining-technologies-automotive-battery-systems-Das-2018.pdf"},{"id":"amada-tab","title":"AMADA WELD TECH: battery welding, using lasers for tab welding (equipment-maker practice note)","accessed":"2026-11-04","url":"https://amadaweldtech.com/blog/battery-welding-using-lasers-for-battery-tab-welding-applications/"},{"id":"ljmu-hilumin","title":"Effect of a ring-shaped laser beam on the weldability of aluminum-to-hilumin for battery tab connectors, J. Laser Appl. 35, 042038 (2023)","accessed":"2026-11-04","url":"https://researchonline.ljmu.ac.uk/id/eprint/21976/1/Effect%20of%20a%20ringshaped%20laser%20beam%20on%20the%20weldability%20of%20aluminum-to-hilumin%20for%20battery%20tab%20connectors.pdf"},{"id":"volta-blade","title":"Volta Foundation: from the BYD Blade cell to module-free battery pack","accessed":"2026-11-04","url":"https://volta.foundation/the-next-generation-battery-pack-design-from-the-byd-blade-cell-to-module-free-battery-pack/"},{"id":"nasa-darcy-2015","title":"Darcy (NASA JSC): Safe, High Performing Li-ion Battery Designs, summary of 2015 findings, NASA Aerospace Battery Workshop","accessed":"2026-11-04","url":"https://ntrs.nasa.gov/api/citations/20150020936/downloads/20150020936.pdf"},{"id":"nasa-haynes-2016","title":"Haynes (NASA JSC): Alternative Orion small cell battery design support","accessed":"2026-11-04","url":"https://ntrs.nasa.gov/api/citations/20160013684/downloads/20160013684.pdf"},{"id":"inficon-leak","title":"INFICON application note: leak testing of battery packs for EVs and HEVs (2019)","accessed":"2026-11-04","url":"https://www.inficon.com/media/5407/download/Leak%20Testing%20Battery%20packs%20mial00en-04%20%281903%29.pdf?v=1"},{"id":"charged-gap","title":"Charged EVs: liquid gap fillers vs thermal pads study (sponsored by LORD, a gap-filler supplier)","accessed":"2026-11-04","url":"https://chargedevs.com/?p=25718"},{"id":"aspen-pyrothin","title":"Aspen Aerogels: stop battery thermal propagation (supplier test report)","accessed":"2026-11-04","url":"https://www.aerogel.com/resources-library/stop-battery-thermal-propagation/"},{"id":"sr-2026-window","title":"Alkhatib et al., Scientific Reports, article in press 2026: 2170 cell thermal window","accessed":"2026-11-04","url":"https://www.nature.com/articles/s41598-026-40953-1_reference.pdf"},{"id":"eenews-gen3","title":"eeNews Europe (2020): Williams wins 350 kW Gen3 Formula E battery deal","accessed":"2026-11-04","url":"https://www.eenewseurope.com/en/williams-wins-350kw-gen3-formula-e-battery-deal/"},{"id":"mt-gen3","title":"Motorsport Technology: Gen3, Formula E big step into uncharted territory (pre-launch)","accessed":"2026-11-04","url":"https://motorsport.tech/formula-e/gen3-formula-es-big-step-into-unchartered-territory"},{"id":"race-gen3","title":"The Race (July 2020): Gen3 Formula E battery","accessed":"2026-11-04","url":"https://the-race.com/formula-e/gen3-formula-e-battery-to-give-more-options-for-race-format/"},{"id":"fe-gen3","title":"ABB FIA Formula E: GEN3 explained","accessed":"2026-11-04","url":"https://www.fiaformulae.com/en/news/487147"},{"id":"autosport-lmdh","title":"Autosport: inside the spec hybrid spine of LMDh cars","accessed":"2026-11-04","url":"https://www.autosport.com/imsa/news/inside-the-spec-hybrid-spine-of-lmdh-cars/10412541/"},{"id":"toyota-ts050","title":"TOYOTA GAZOO Racing: TS050 Hybrid 2016","accessed":"2026-11-04","url":"https://toyotagazooracing.com/wec/cars/2016"},{"id":"ugm-coldplate","title":"Alsyahron, UGM undergraduate thesis 2025: double serpentine mini-channel cold plate (abstract)","accessed":"2026-11-04","url":"https://etd.repository.ugm.ac.id/penelitian/detail/257073"},{"id":"catalog-60664","title":"Equipment catalogue table of creepage distances, stated as taken from IEC 60664-1 with a 1.5 mm floor","accessed":"2026-11-04","url":"https://www.tamhash.co.il/catalog400A/files/assets/basic-html/page-535.html","note":"Secondary reproduction: verify against the paywalled IEC 60664-1 before release."},{"id":"iec-60664-1","title":"IEC 60664-1 Insulation coordination for equipment within low-voltage supply systems (paywalled; scope cited, clauses not read)","accessed":"2026-11-04"}],"entries":[{"id":"cell-18650-envelope","kind":"dimension","tier":1,"title":"18650 cell envelope: datasheet maximum","summary":"Model the 18650 at its datasheet maximum: VTC6 is 18.50 mm max dia x 65.20 mm max long with sleeve, 46.5 g average. Pockets clear the maximum, never the nominal 18.0 x 65.0.","applies":["18650","cell holder"],"basis":"SRC: Sony US18650VTC6 technical information 1.2.2, 1.2.3. Other 18650s differ; read that cell's sheet.","sources":["sony-vtc6"],"tags":["cylindrical"],"value":{"table":[{"cell":"Sony US18650VTC6","dia_max_mm":18.5,"length_max_mm":65.2,"mass_g":46.5}]},"see":["electronics/battery-18650-compartment","desktop-robots/battery-18650-bay"]},{"id":"cell-21700-envelope","kind":"dimension","tier":1,"title":"21700 cell envelope: two datasheets differ by 0.45 mm","summary":"21700 envelope varies by maker: Samsung 50E max dia 21.25 x 70.80 mm, 69.5 g max; Molicel P42A max dia 21.7 x 70.2 mm, 70 g max. Size holder bores for the chosen cell, and treat the name as nominal only.","applies":["21700","cell holder"],"basis":"SRC: Samsung 50E spec V1.0 sec 3 and Fig 1 (with sleeve); Molicel P42A data sheet, physical characteristics.","sources":["samsung-50e","molicel-p42a"],"tags":["cylindrical"],"value":{"table":[{"cell":"Samsung INR21700-50E","dia_max_mm":21.25,"height_max_mm":70.8,"mass_max_g":69.5},{"cell":"Molicel INR-21700-P42A","dia_max_mm":21.7,"height_max_mm":70.2,"mass_max_g":70}]},"see":["automotive/cell-module-sizes-ev"]},{"id":"cell-4680-envelope","kind":"dimension","tier":2,"title":"4680 cell: size, mass and polarity as benchmarked","summary":"4680 is about 46 mm dia x 80 mm, measured 355 g, 0.5 to 0.6 mm can wall (estimate). Positive button on top, insulated from the can; the can is negative, crimped at the bottom, with the vent apparently at the bottom too. No public datasheet.","applies":["4680"],"basis":"SRC: Battery Design benchmark, mass from UCSD LESC. Dimensions and wall are its estimates; bottom vent is its inference, unconfirmed.","sources":["bd-4680"],"tags":["cylindrical","4680","tabless"],"value":{"typical":80,"unit":"mm"}},{"id":"cell-prismatic-vda","kind":"dimension","tier":2,"title":"VDA prismatic formats, W x H x T","summary":"VDA prismatic sizes in mm: HEV 120x85x12.5, PHEV1 173x85x21, PHEV2 148x91x26.5, PHEV2+ 148x125x26.5, EV1 173x115x32, EV2 173x115x45. Terminal height varies by maker even in PHEV2, so check the actual cell.","applies":["prismatic cell"],"basis":"SRC: Battery Design VDA table, which it labels a proposed standard. It warns to check the spec sheet and the real cell.","sources":["bd-vda"],"tags":["prismatic","vda"],"value":{"table":[{"format":"HEV","w":120,"h":85,"t":12.5},{"format":"PHEV1","w":173,"h":85,"t":21},{"format":"PHEV2","w":148,"h":91,"t":26.5},{"format":"PHEV2+","w":148,"h":125,"t":26.5},{"format":"EV1","w":173,"h":115,"t":32},{"format":"EV2","w":173,"h":115,"t":45}]}},{"id":"swell-allowance-life","kind":"rule","tier":1,"title":"Swelling allowance over cell life","summary":"Stack and cell thickness grow 10 to 20% over life in prismatic and pouch cells. Reserve that travel in the stack, with pads or a sprung end plate, rather than building the module to the new-cell stack height.","applies":["prismatic cell","pouch cell","battery module"],"basis":"SRC: Battery Design expansion and module pages state 10-20%. LFP is described as far lower, silicon anodes as higher, no figures given.","sources":["bd-expansion","bd-module"],"tags":["stack"],"value":{"min":10,"max":20,"unit":"%"}},{"id":"swell-clamp-load-phev2","kind":"rule","tier":2,"title":"PHEV2 stack clamp load, new to end of life","summary":"A 12-cell PHEV2 module rises from about 3 kN clamp at assembly to about 30 kN at end of life with graphite, 50 kN with graphite-silicon. Size end plates and tie rods for the end-of-life figure, about 10 to 17 times the build load.","applies":["prismatic cell","end plate","banding"],"basis":"SRC: Battery Design module force figures. One published example, not a general limit; pressure over 91 x 148 mm is about 0.22, 2.2 and 3.7 MPa by division.","sources":["bd-expansion"],"tags":["swelling","end-plate","clamp"],"value":{"table":[{"stage":"BOL assembly","force_kN":3},{"stage":"EOL NMC/graphite","force_kN":30},{"stage":"EOL NMC/graphite-Si","force_kN":50}]}},{"id":"pouch-fixing-limits","kind":"rule","tier":1,"title":"Pouch cell fixing: 80% of face, tabs unloaded","summary":"Fix pouch cells by their large faces over at least 80% of each face used; tabs carry no mechanical load and must not press into the pouch. Stress limit at 40/40/20 g: 0.05 MPa shear, 1.0 MPa compression on 80% of the face area.","applies":["pouch cell","cell holder"],"basis":"SRC: FS Rules 2026 EV 5.5 (pouch cell clause; sub-number scrambled in extraction). A competition rule, and a usable conservative sizing case elsewhere.","sources":["fs-rules-2026"],"tags":["mounting"],"value":{"table":[{"limit":"fixed area of face","value":">= 80 %"},{"limit":"shear on cell","value":"<= 0.05 MPa"},{"limit":"compression on cell","value":"<= 1.0 MPa"},{"limit":"cells in series without stress analysis","value":"<= 8"}]}},{"id":"pouch-pressure-pads","kind":"feature","tier":2,"title":"Pouch compression pads even out contact pressure","summary":"Without pads, pouch pressure concentrates at tab welds and jelly-roll folds; with PU pads it spreads smoothly. Fixed-gap clamping swung 0.9 to 1.3 MPa over a cycle around a 1.0 MPa setpoint. Pads insulate, so they fight face cooling.","applies":["pouch cell"],"basis":"SRC: Battery Design on an operando mapping study, small 63.1 x 58.3 mm stack. Magnitudes are for that cell, not a design target.","sources":["bd-pressure-map"],"tags":["pouch","pads","swelling"],"value":{"min":0.9,"max":1.3,"unit":"MPa"},"see":["desktop-robots/lipo-pouch-bay-dimension"]},{"id":"can-polarity-weld","kind":"rule","tier":1,"title":"Cylindrical can is negative and thin: weld, never solder","summary":"On 18650 and 21700 cells the steel can is the negative terminal, typically about 0.3 mm thick in the wall. Weld leads, never solder to the cell (Samsung 2.1.1), and avoid excess force on the negative end. A busbar touching the shoulder shorts to negative.","applies":["18650","21700","busbar"],"basis":"SRC: Samsung 50E spec 5.2.1 and 2.1.1; can thickness from AMADA practice note. LJMU quotes 0.5 mm Hilumin casings, so measure. Shoulder short: EST from can polarity.","sources":["samsung-50e","amada-tab","ljmu-hilumin"],"tags":["polarity"],"value":{"typical":0.3,"unit":"mm"}},{"id":"crimp-keepout","kind":"note","tier":2,"title":"Crimp-side keepout has no published dimension","summary":"EST: keep busbars, tabs and adhesive off the crimp, cap vent openings and the rolled shoulder of a cylindrical cell. No datasheet read gives a keepout figure, so take it from the cell drawing or a measured sample, and never close the vent path with potting.","applies":["18650","21700","cell holder"],"basis":"EST: Soldering heat can disturb the vent (Das 2018) and the vent must open freely (Battery Design). No numeric keepout found in any source opened.","sources":["das-2018","bd-venting"],"tags":["crimp","vent","keepout"]},{"id":"cell-gap-propagation","kind":"rule","tier":1,"title":"Cell-to-cell gap against propagation: 0.5 mm failed, 3 mm design held","summary":"NASA found about 0.5 mm 18650 spacing too tight; the non-propagating tool battery used 3 mm with G10/FR4 capture plates and 100 um mica sleeves. Proposed LLB fix: 80 cells to 65, up to ~2 mm. Touching cells nearly assure propagation.","applies":["18650","cell holder","thermal runaway"],"basis":"SRC: Darcy, NASA JSC 2015, tests of specific 18650 cells in small batteries. Gap alone is not sufficient, and higher-energy cells rupture more.","sources":["nasa-darcy-2015"],"tags":["spacing"],"value":{"value":3,"unit":"mm","note":"one tested 18650 design, with capture plates and mica; 2 mm proposed, untested"},"see":["automotive/cell-module-sizes-ev"]},{"id":"sidewall-rupture","kind":"rule","tier":2,"title":"High-energy thin cans rupture through the side","summary":"Cells above about 250 Wh/kg with 0.005 in can walls carry a high risk of side-wall rupture, which sent ejecta straight into the neighbour in NASA tests. A top-vent path alone will not protect: sleeve the cans and keep interstitial barriers.","applies":["18650","21700","thermal runaway"],"basis":"SRC: Darcy 2015 and Haynes 2016 (Orion 14P banks with interstitial material to stop side-can failures). Rupture rate depends on the specific cell.","sources":["nasa-darcy-2015","nasa-haynes-2016"],"tags":["rupture","propagation","can"],"value":{"value":0.005,"unit":"in"}},{"id":"vent-direction","kind":"rule","tier":1,"title":"Point cell vents down a clear path away from neighbours","summary":"Direct all cell vents one way, into a plenum clear of adjacent cells, with a tortuous path to screened pack ports: NASA ports read 66 to 69 C, even in a redesign that still propagated. Dead-ended ejecta pooled by a wall; in the baseline test one housing base hit 354 C.","applies":["thermal runaway","battery module"],"basis":"SRC: Darcy 2015 design rules and measured temperatures for small 18650 batteries; ejecta is conductive, so insulate the plenum. Not scaled to large packs.","sources":["nasa-darcy-2015"],"tags":["plenum"],"value":{"min":66,"max":69,"unit":"C"}},{"id":"cell-datasheet-temps","kind":"rule","tier":2,"title":"Cell datasheet temperature limits, read at the surface","summary":"Sample limits: Samsung 50E charge 0 to 45 C, discharge -20 to 60 C, discharge over-temperature protection at no more than 70 C on the can. Molicel P42A charge 0 to 45 C, discharge -40 to 60 C. Put the sensor at the hottest location.","applies":["18650","21700"],"basis":"SRC: Samsung 50E sec 3.16 and note 2; Molicel P42A characteristics table.","sources":["samsung-50e","molicel-p42a"],"tags":["temperature","sensor"],"value":{"min":-40,"max":70,"unit":"C"}},{"id":"tab-vs-can-thickness","kind":"rule","tier":1,"title":"Tab thickness against can thickness for laser welds","summary":"Keep the tab thinner than the can or terminal it lands on: a practice rule is 50 to 60% of a 0.3 mm can, so about 0.15 to 0.18 mm. The weld must not penetrate the can. Coin thicker tabs down locally at the weld.","applies":["tab welding","busbar"],"basis":"SRC: AMADA practice note for the 50-60% rule and no-penetration; Das 2018 confirms tab thinner than terminal. 0.15-0.18 mm is arithmetic.","sources":["amada-tab","das-2018"],"tags":["laser"],"value":{"min":50,"max":60,"unit":"%"}},{"id":"resistance-weld-limits","kind":"process","tier":2,"title":"Resistance spot welding: up to 0.4 mm tab","summary":"Resistance spot welding joins steel, nickel, copper and aluminium tabs up to 0.4 mm, but Cu and Al are difficult from conductivity and oxide. Add projections on the tab to concentrate energy; the electrodes need access to one side.","applies":["tab welding","18650","21700"],"basis":"SRC: Das 2018 sec 2.2. Heat-damage risk if poorly controlled is noted there and on Battery Design; no numeric cell limit is published in either.","sources":["das-2018"],"tags":["resistance","spot-weld"],"value":{"max":0.4,"unit":"mm"}},{"id":"laser-weld-fitup","kind":"process","tier":2,"title":"Laser tab welding needs clamped zero-gap fit-up","summary":"Laser welding is fast, one-sided and low in heat input but has a very small gap tolerance. Design a clamp over each weld with line of sight kept open. Published coupon stack: 0.5 mm Al on 0.5 mm Hilumin. Foils must be in close contact.","applies":["tab welding"],"basis":"SRC: Das 2018 sec 2.7 and 3.1, LJMU 2023 coupons, AMADA. No gap figure is given in mm; agree one with the weld vendor and record it.","sources":["das-2018","ljmu-hilumin","amada-tab"],"tags":["laser","fit-up"],"value":{"typical":0.5,"unit":"mm","note":"published coupon foil thickness, NOT a gap tolerance; no gap figure is published"}},{"id":"ultrasonic-weld","kind":"process","tier":2,"title":"Ultrasonic welding: pouch tabs, two-sided access","summary":"Ultrasonic welding runs at 20 kHz or above, in the solid state at about 0.3 to 0.5 of absolute melting temperature. It joins foil stacks and dissimilar metals but needs anvil and sonotrode access on both sides, and vibration can damage cylindrical or prismatic terminals.","applies":["tab welding","pouch cell"],"basis":"SRC: Das 2018 sec 2.1. Used on Nissan Leaf, Chevrolet Volt, Spark and Bolt per that review.","sources":["das-2018"],"tags":["ultrasonic"],"value":{"min":20000,"unit":"Hz"}},{"id":"wire-bond","kind":"process","tier":2,"title":"Ultrasonic wedge wire bonding, wire as cell fuse","summary":"Wire bonding uses Al, Cu or Au wire, typically under 500 um, and the wire can act as the per-cell fuse. Cells and busbar must be rigid, often bonded by adhesive, or lost vibration kills the weld. Leave wedge-head access above every terminal.","applies":["tab welding","battery module"],"basis":"SRC: Das 2018 sec 2.4. Head clearance is EST; no dimension given. NASA asks for individually fused parallel cells, which this provides.","sources":["das-2018","nasa-darcy-2015"],"tags":["wire-bond","fuse"],"value":{"max":500,"unit":"um"}},{"id":"prismatic-tab-coin","kind":"feature","tier":2,"title":"Prismatic terminal tabs: coin down, choose 1xxx aluminium","summary":"Coin thick prismatic tabs to 0.01 to 0.02 in for a lap weld, cutting heat into the can. Use 1080 or 1100 aluminium; 6061 cracks when welded, unless a 4047 preform adds silicon.","applies":["prismatic cell","busbar","tab welding"],"basis":"SRC: AMADA practice note. A maker practice figure, not a standard.","sources":["amada-tab"],"tags":["prismatic","coin","aluminium"],"value":{"min":0.01,"max":0.02,"unit":"in"}},{"id":"pack-joints-bolted","kind":"rule","tier":2,"title":"Weld within the module, bolt at pack level","summary":"Pack-level connections are normally nut and bolt because welds block service, per a 2018 review; bolts add weight and resistance and can loosen. Keep bolted joints reachable with modules in place.","applies":["busbar","battery pack"],"basis":"SRC: Das 2018 Table 1 and sec 3.1. Accessibility is EST from the service reason it gives.","sources":["das-2018"],"tags":["bolted","service"],"value":{"options":["welded inside module","bolted between modules"]}},{"id":"hilumin-can-material","kind":"material","tier":2,"title":"Hilumin nickel-plated steel for cans and tabs","summary":"Hilumin, electrolytically nickel-plated cold-rolled strip steel, is typically 0.5 mm in cell casings. It forms and welds well; it conducts far worse than copper. Cu-to-steel joints corrode without a coating.","applies":["18650","21700","busbar"],"basis":"SRC: LJMU J. Laser Appl. 2023 intro and Table I.","sources":["ljmu-hilumin"],"tags":["hilumin","steel"],"value":{"typical":0.5,"unit":"mm"}},{"id":"busbar-materials","kind":"material","tier":2,"title":"Tab and busbar materials: Ni, Cu, Al properties","summary":"Density and resistivity: Cu 8.92 g/cm3, 0.017 uOhm m; Al 2.80, 0.026; Ni 8.90, 0.067. Conductivity W/mK: Cu 391, Al 231, Ni 97.5. Al needs about 1.6 times the copper section for the same current but saves mass.","applies":["busbar"],"basis":"SRC: LJMU 2023 Table I for properties (resistivity unit read from a damaged PDF extract); 1.6x from Battery Design.","sources":["ljmu-hilumin","bd-busbars"],"tags":["copper","aluminium","nickel"],"value":{"table":[{"m":"Cu","g_cm3":8.92,"uOhm_m":0.017,"W_mK":391.1,"UTS_MPa":"200-360"},{"m":"Al","g_cm3":2.8,"uOhm_m":0.026,"W_mK":231,"UTS_MPa":"100-150"},{"m":"Ni","g_cm3":8.9,"uOhm_m":0.067,"W_mK":97.5,"UTS_MPa":345}]},"see":["materials/copper-c110","materials/al-6061-t6"]},{"id":"dissimilar-imc","kind":"rule","tier":2,"title":"Dissimilar tab joints: intermetallics set strength and resistance","summary":"Al to steel welds form brittle intermetallics such as Fe2Al5. In 0.5 mm Al to 0.5 mm Hilumin lap welds a 0.4 core-to-ring power ratio gave best lap-shear, 0.2 lowest electrical resistance, so strength and conductivity trade off.","applies":["busbar","tab welding"],"basis":"SRC: LJMU 2023 abstract. Only 1100 Al to Hilumin tested. Das 2018 notes IMCs raise resistance. No universal IMC thickness limit found.","sources":["ljmu-hilumin","das-2018"],"tags":["imc","dissimilar"],"value":{"min":0.2,"max":0.4,"unit":"ratio"}},{"id":"busbar-current-density","kind":"rule","tier":1,"title":"Busbar section: start at 5 A/mm2 of copper","summary":"Size a copper pack busbar first at 5 A per mm2 continuous, a figure from the 5.9 A/mm2 fit slope of five EV busbars, then run electrothermal analysis. Aluminium needs about 1.6 times the area.","applies":["busbar"],"basis":"SRC: Battery Design busbars page. A starting point for a cooled EV pack, not a limit. Peak current and connector temperature can govern.","sources":["bd-busbars"],"tags":["current-density"],"value":{"value":"5 A/mm2 Cu to start; 5.9 A/mm2 fit to 5 EV busbars","unit":"text"}},{"id":"busbar-bolted-overlap","kind":"rule","tier":2,"title":"Bolted busbar joint overlap","summary":"Overlap a bolted busbar joint by 5 to 10 times the busbar thickness; tin-plate aluminium joints against contact resistance and corrosion. For a 3 mm bar that is 15 to 30 mm. Torque and fastener class govern joint life.","applies":["busbar"],"basis":"SRC: Battery Design busbars page. No authoritative pack torque table opened: take torque from the fastener chart and the terminal maker.","sources":["bd-busbars"],"tags":["bolted","overlap","torque"],"value":{"min":5,"max":10,"unit":"ratio"},"see":["hardware/torque-table-class-8-8","hardware/clearance-holes-metric"]},{"id":"cell-holder-plate","kind":"feature","tier":2,"title":"Cylindrical cell holder plate","summary":"EST: bore at cell max dia + 0.2 mm, so 21.9 for P42A, with pitch set by the gap rule, 24.7 mm for 3 mm gap. Add a lip about 1.5 mm with window to expose the terminal for welding. Hold cells against 40/40/20 g in competition.","applies":["cell holder","21700","18650"],"basis":"EST: Fit and lip from worked geometry here, no published holder standard opened. Gap: Darcy 2015. G10/FR4 capture plates are the NASA practice. Loads: FS T 3.3.1.","sources":["nasa-darcy-2015","fs-rules-2026","molicel-p42a"],"tags":["holder","capture-plate"],"value":{"typical":24.7,"unit":"mm"}},{"id":"mass-fraction-cell-pack","kind":"rule","tier":2,"title":"Cell share of pack mass: 60 to 65% with modules, 75 to 80% without","summary":"Budget cell mass at 60 to 65% of pack for cell-module-pack and 75 to 80% for cell-to-pack; one dataset averages 62.9%. Examples: BYD Han 90%, Model 3 LR 63.5%, Formula E Gen2 61%. Pack Wh/kg is about 65% of cell for NMC, 70% for LFP.","applies":["battery pack","cell to pack"],"basis":"SRC: Battery Design module page, ratio list and chemistry page. BYD Han year 2023; Tesla and FE entries undated. Published teardown figures differ by method.","sources":["bd-module","bd-ctp-ratio","bd-ctp-chem"],"tags":["mass-fraction","ctp"],"value":{"min":60,"max":80,"unit":"%"}},{"id":"cell-to-pack-structure","kind":"process","tier":2,"title":"Cell-to-pack: cells as structure","summary":"Module-free Blade pack: estimated 62.4% volume and 84.5% mass cell ratio, against about 50% and at most 77% for module packs, and about 50 mm lower. Cells stiffen honeycomb panels, so the stack becomes the load path and cell replacement stops.","applies":["cell to pack","battery pack"],"basis":"SRC: Volta Foundation estimates for Blade. Battery Design gives 10-15% volume gain for C2P. Service loss is EST from bonded construction.","sources":["volta-blade","bd-module"],"tags":["ctp","blade","structure"],"value":{"typical":84.5,"unit":"%"}},{"id":"end-plate-tie-rods","kind":"feature","tier":2,"title":"Module end plates and tie rods carry the swelling load","summary":"EST: with 50 kN end-of-life load and four tie rods, each rod sees 12.5 kN. Size the plate for bending over the cell face, 91 x 148 mm on PHEV2, not for assembly clamp. Adhesive may replace tie rods on prismatic stacks.","applies":["end plate","banding","prismatic cell"],"basis":"EST: Division of the Battery Design 50 kN figure across 4 rods; rod count assumed. Adhesive option is stated on the Battery Design module page.","sources":["bd-expansion","bd-module"],"tags":["end-plate","tie-rod"],"value":{"typical":12.5,"unit":"kN"}},{"id":"enclosure-fs-walls","kind":"dimension","tier":2,"title":"Competition accumulator container wall minimums","summary":"FS 2026 container minimum: floor 3.2 mm Al or 1.25 mm steel; walls, covers and lids 2.3 mm Al or 0.9 mm steel. Composites need test data and 2 mm steel backing at each mount. Brackets 4 mm Al or 1.6 mm steel with gussets, at least 2 mounts.","applies":["accumulator","battery pack"],"basis":"SRC: FS Rules 2026 EV 5.5. Calculations at 60 C ambient for non-metals except continuous-fibre laminates. Check the year and event: FSAE and JSAE differ.","sources":["fs-rules-2026"],"tags":["enclosure","fsae","walls"],"value":{"table":[{"part":"floor","al_mm":3.2,"steel_mm":1.25},{"part":"walls, covers, lids","al_mm":2.3,"steel_mm":0.9},{"part":"brackets","al_mm":4,"steel_mm":1.6},{"part":"composite backing plates","steel_mm":2}]}},{"id":"enclosure-fire-rating","kind":"rule","tier":2,"title":"Enclosure material fire rating","summary":"F1 2026 requires ES enclosure materials to at least UL94 V0 equivalent unless cells are shown not to self-heat; FS requires fire-retardant container materials. Check a composite or magnesium enclosure resin and coating against this before committing.","applies":["battery pack","energy store"],"basis":"SRC: FIA C5.20 group, FS T 1.2.1 and EV 5.5. No opened source compared Al, composite and magnesium pack enclosures numerically; the check is EST.","sources":["fia-2026-c21","fs-rules-2026"],"tags":["enclosure","composite","magnesium","ul94"],"value":{"value":"UL94 V0","unit":"text"}},{"id":"service-disconnect","kind":"feature","tier":2,"title":"Service disconnects and maintenance plugs","summary":"Plugs split FS accumulators into segments of at most 120 V, 6 MJ, 12 kg, breaking both poles, without tools, and show whether open or closed. The HVD must come out within 10 s. Keep both reachable with the pack lid on.","applies":["battery pack","accumulator"],"basis":"SRC: FS Rules 2026 EV 5.3, EV 5.4, EV 4.8. F1 equally requires manual isolation of ES poles. Lid-on reach is EST.","sources":["fs-rules-2026","fia-2026-c21"],"tags":["msd","hvd","service"],"value":{"max":120,"unit":"V"}},{"id":"vent-gas-sizing","kind":"rule","tier":2,"title":"Vent gas volume for sizing pack venting","summary":"Estimate vent gas at 1 to 2 litres per Ah as a rough figure; measured 780 L/kg for NMC/LMO, 42 L/kg for LFP. Breathing vents do not relieve this: use rupture discs or relief valves. Size from a test of the actual cell.","applies":["thermal runaway","battery pack"],"basis":"SRC: Battery Design venting page, citing Sturk et al. Bases differ per Ah and per kg, so do not mix them. No burst pressure or vent area figures were found.","sources":["bd-venting","bd-runaway"],"tags":["vent","gas","burst-disc"],"value":{"value":"1-2 L/Ah rough","unit":"text"}},{"id":"pressure-relief-sealed","kind":"rule","tier":2,"title":"A sealed pack needs a pressure relief path","summary":"FS 2026 requires a pressure relief valve on any completely sealed container and ventilation where explosive gas can build. F1 2026 requires an FIA-approved gas evacuation system, by 21 March of the year before introduction, so the enclosure survives venting.","applies":["battery pack","energy store"],"basis":"SRC: FS Rules 2026 EV 5.5; FIA C5.20 group. Both set the function, not a dimension.","sources":["fs-rules-2026","fia-2026-c21"],"tags":["vent","relief"],"value":{"options":["relief valve","rupture disc","gas evacuation duct"]}},{"id":"sensing-density","kind":"rule","tier":2,"title":"Temperature and voltage sense density","summary":"Series-production practice is one temperature sensor per 4 to 8 cells, and a 12S module needs 13 sense wires. FS 2026 requires sensing at least 30% of lithium cells, with sensors on the cell or under 10 mm along the current path. Route the harness in CAD.","applies":["bms","battery module"],"basis":"SRC: Battery Design module page; FS Rules 2026 EV 5.8.","sources":["bd-module","fs-rules-2026"],"tags":["sensor","harness","bms"],"value":{"min":4,"max":8,"unit":"count"}},{"id":"cell-temp-window","kind":"rule","tier":1,"title":"Cell thermal window and maximum spread","summary":"Design the thermal path to hold cells near 15 to 35 C with under 3 to 5 C spread across the module. Above about 130 C, exothermic reactions begin. FS caps measured cell temperature at 60 C or the datasheet limit, if lower.","applies":["cold plate","battery module"],"basis":"SRC: Alkhatib 2026 for window, stated as usual range, in press; Battery Design for 130 C; FS EV 5.8. Motorsport duty may run hotter: not published.","sources":["sr-2026-window","bd-runaway","fs-rules-2026"],"tags":["temperature"],"value":{"min":15,"max":35,"unit":"C"}},{"id":"gap-filler","kind":"material","tier":2,"title":"Gap filler conductivity and thickness","summary":"Pack gap fillers run 2 to 4 W/mK, pads tested at 1 mm. With shimmed gaps a 2 W/mK filler beat a 4 W/mK pad, as hard pads do not conform; at 2 W/mK, no tolerance, filler removed 24% more heat than same-grade pad. Leave a filled gap for flatness error, and limit force on cells.","applies":["cold plate","battery module"],"basis":"SRC: Charged EVs on a LORD-sponsored study: the supplier gains from this result, so treat as indicative. Filler force on cells: EST, no figure published.","sources":["charged-gap"],"tags":["gap-filler","tim"],"value":{"min":2,"max":4,"unit":"W/mK"},"see":["electronics/tim-gap"]},{"id":"cold-plate-channel","kind":"process","tier":2,"title":"Cold plate geometry and pressure drop","summary":"One lab figure: an aluminium double-serpentine mini-channel plate 104 x 80 x 6 mm, 1 to 1.25 L/min, lowest drop was 8.96 kPa, on dielectric fluid. EST: for channel depth, solve flow and pressure drop per pack; no general published depth was found.","applies":["cold plate"],"basis":"EST: Weak source, an undergraduate thesis abstract with no internal dimensions. Use only as an order of magnitude. kPa kept as text since not a schema unit.","sources":["ugm-coldplate"],"tags":["channel","pressure-drop"],"value":{"value":"8.96 kPa","unit":"text"}},{"id":"cooling-position-cyl","kind":"rule","tier":2,"title":"Cylindrical base cooling against side cooling","summary":"For 21700 and 4680 cells, base cooling gives about 12% better heat transfer than side cooling, since heat runs along the jelly roll. Plan an electrically insulated contact on the cell end, and check the vent end stays clear.","applies":["21700","4680","cold plate"],"basis":"SRC: Battery Design module page for 12%. Reasoning and vent-end clause are EST.","sources":["bd-module"],"tags":["base-cooling"],"value":{"typical":12,"unit":"%"}},{"id":"tab-vs-surface-cooling","kind":"rule","tier":2,"title":"Pouch tab cooling against surface cooling","summary":"In a 5 Ah pouch study, surface cooling lost 9.2% usable capacity at a 10-minute rate against 1.2% for tab cooling, and degraded about 3 times faster over 1000 cycles. Pouch in-plane conduction is 10 to 100 times through-plane. Size tabs as heat paths too.","applies":["pouch cell","cold plate"],"basis":"SRC: Battery Design on Hunt et al. 2016, read second-hand; module page for conduction. Later work finds large cells may favour surface cooling over life.","sources":["bd-pouch-cooling","bd-module"],"tags":["tab-cooling"],"value":{"typical":3,"unit":"ratio"}},{"id":"immersion-cooling","kind":"process","tier":2,"title":"Dielectric immersion in racing packs","summary":"Formula E Gen2 used a 3M dielectric cooling fluid (reported 2020), and F1 2026 packs are reported to use dielectric oil. Immersion needs every cell wetted, sealed flow channels, and fluid-compatible seals and potting, and adds fluid mass.","applies":["energy store","cold plate"],"basis":"SRC: The Race for Formula E; Battery Design quoting Craig Scarborough for F1, secondary. Team details are unpublished. Consequences for CAD are EST.","sources":["race-gen3","bd-f1"],"tags":["immersion","dielectric","motorsport"],"value":{"options":["Formula E Gen2: 3M dielectric","F1 2026: dielectric oil (reported)"]}},{"id":"runaway-barrier-mica","kind":"material","tier":2,"title":"Mica runaway barrier","summary":"Muscovite mica resists about 500 to 600 C continuous, phlogopite 800 C or higher. NASA used 100 um mica paper sleeves on 18650 cans. Mica also insulates but is denser than aerogel and does not absorb swelling.","applies":["thermal runaway"],"basis":"SRC: Battery Design mica page; Darcy 2015. No conductivity figure on an opened page. Swelling clause is EST from it being a rigid sheet.","sources":["bd-mica","nasa-darcy-2015"],"tags":["mica","barrier"],"value":{"min":500,"max":800,"unit":"C"}},{"id":"runaway-barrier-aerogel","kind":"material","tier":2,"title":"Aerogel cell-to-cell barrier","summary":"Supplier test: a 2.35 mm PyroThin barrier, compressed about 50% at end-of-life pressure, between two 62 Ah prismatic cells held the neighbour at 130 C peak with no runaway over 30 min. It sits in the swelling stack, so count its compressed thickness.","applies":["thermal runaway","prismatic cell"],"basis":"SRC: Aspen Aerogels own report of its product, on a mini-module conduction test only, not a full pack. Vendor claims 1400 C rating; independent data absent here.","sources":["aspen-pyrothin"],"tags":["aerogel","barrier"],"value":{"typical":2.35,"unit":"mm"}},{"id":"creepage-table","kind":"dimension","tier":1,"title":"Creepage by rated insulation voltage Ui, pollution degree, material group","summary":"Creepage mm from IEC 60664-1 as tabulated by a catalogue against rated insulation voltage Ui: 400 V PD2 2.5 (I) to 5 (IIIa), PD3 6.3 to 8; 800 V PD2 5 to 10, PD3 12.5 to 16; 1000 V PD2 6.3 to 12.5, PD3 16 to 20. Treat the pack interior as PD3; double for reinforced insulation.","applies":["busbar","battery pack"],"basis":"SRC: Catalogue column is rated insulation voltage Ui, not working voltage; verify on the IEC text. PD3 default and doubling from Battery Design, a view, not a clause. See automotive for clearance.","sources":["catalog-60664","bd-creepage","iec-60664-1"],"tags":["iec-60664"],"value":{"table":[{"V":400,"pd2_I":2.5,"pd2_II":3.6,"pd2_III":5,"pd3_I":6.3,"pd3_II":7.1,"pd3_IIIa":8},{"V":800,"pd2_I":5,"pd2_II":7.1,"pd2_III":10,"pd3_I":12.5,"pd3_II":14,"pd3_IIIa":16},{"V":1000,"pd2_I":6.3,"pd2_II":9,"pd2_III":12.5,"pd3_I":16,"pd3_II":18,"pd3_IIIa":20}]},"see":["automotive/busbar-clearance-creepage"]},{"id":"clearance-notes","kind":"rule","tier":2,"title":"HV clearance: impulse rating, altitude, tolerance","summary":"For 800 V at OVC III one guide quotes about 8 kV impulse and 8 mm or more basic clearance, while also giving 4 to 6 mm as a rule of thumb. Correct clearance by about 1.14 at 3000 m. A 0.5 mm placement error can break compliance: stack it up.","applies":["busbar","battery pack"],"basis":"SRC: Battery Design creepage page, which contains this conflict itself; resolve from the IEC tables. Flagged, not reconciled.","sources":["bd-creepage","iec-60664-1"],"tags":["clearance","altitude"],"value":{"min":4,"max":8,"unit":"mm"}},{"id":"isolation-resistance","kind":"rule","tier":1,"title":"HV isolation resistance targets","summary":"Road rules require at least 100 ohm/V on DC buses and 500 ohm/V on AC buses, in R100 and FMVSS 305; FS sets 500 ohm/V against max tractive voltage. After immersion or crush this must hold, so keep the creepage dry with drains and seals.","applies":["battery pack","bms"],"basis":"SRC: UN R100 02 series, 5.1; FMVSS 305 S5.3 (standard ends 2027-09-01 for new builds per its text). F1 uses 100/500 to define a live part. Drain clause is EST.","sources":["un-r100-02","fmvss-305","fs-rules-2026","fia-2026-c21"],"tags":["imd"],"value":{"value":"100 ohm/V DC; 500 ohm/V AC","unit":"text"}},{"id":"ip-touch-bonding","kind":"rule","tier":2,"title":"Touch protection and chassis bonding","summary":"R100 asks IPXXD inside the cabin and luggage space and IPXXB elsewhere: the 12 mm jointed finger probe enters up to 80 mm without touching live parts. Bond exposed conductive parts at under 0.1 ohm to chassis, so plan a bare bonding land.","applies":["battery pack"],"basis":"SRC: UN R100 02 series 5.1.1 and Annex 3; FMVSS 305 S5.3 gives the same 0.1 ohm. Bonding land is EST.","sources":["un-r100-02","fmvss-305"],"tags":["ipxxb","bonding"],"value":{"value":"< 0.1 ohm","unit":"text"}},{"id":"contactors-fusing","kind":"feature","tier":2,"title":"Contactors, fuse, pre-charge, HVIL","summary":"Fit a contactor per pole and a fuse near the cells. F1 2026: dielectric test at ES max DC plus 1200 V for 60 s, under 1 mA; over 50 MOhm open at 500 V DC. FS: two relays, pre-charge to 95%, under 60 V within 5 s. Plan the bay and creepage for these.","applies":["battery pack","energy store","bms"],"basis":"SRC: FIA C5.20 and C5.21 groups; FS EV 5.6, 5.7, 6.1. F1 also requires detecting unmated phase conductors, an HVIL function, with up to 1 s debounce.","sources":["fia-2026-c21","fs-rules-2026"],"tags":["contactor","fuse","hvil","precharge"],"value":{"value":"1200 V above ES max for 60 s, < 1 mA","unit":"text"}},{"id":"hv-connectors","kind":"rule","tier":2,"title":"HV connector requirements seen in F1 2026","summary":"F1 2026 HV connectors: IP2X unmated, IP65 mated, keyed to one socket, orange HV looms, and PD3 or higher for connectors opened in the garage. At least 70% of the ES enclosure outside must be orange, RAL 2003 to 2011 except 2007.","applies":["energy store","battery pack"],"basis":"SRC: FIA Section C Issue 21, C5.21 group, 2026 rules, changes by issue. Compliance needs third-party IEC 60529 or ISO 20653 test.","sources":["fia-2026-c21"],"tags":["connector","ip65","orange"],"value":{"options":["IP2X unmated","IP65 mated","PD3 when opened in the garage"]},"see":["standards-testing/test-ip-ratings-iec-60529"]},{"id":"enclosure-ip67-leak","kind":"test","tier":2,"title":"IP67 pack housing leak test","summary":"A pack housing that must meet IP67 is typically helium-tested to about 5e-3 mbar l/s (0.3 sccm). One method pulls 100 to 250 mbar under and back-fills to 100 to 250 mbar over, so walls, seals and lid must hold that pressure both ways. Provide a test port.","applies":["battery pack","accumulator"],"basis":"SRC: INFICON note, a tester maker; typical rather than regulatory. Test-port clause is EST. Gasket groove and IP definition are in the linked entries.","sources":["inficon-leak"],"tags":["ip67","leak","helium"],"value":{"value":"5e-3 mbar l/s","unit":"text"},"see":["automotive/battery-enclosure-ip67","standards-testing/gasket-groove-for-ip-sealing","electronics/ip67-gasket-groove"]},{"id":"test-un38-3","kind":"test","tier":1,"title":"UN 38.3 T1 to T8 transport tests and what they want","summary":"T1 11.6 kPa 6 h; T2 72 C and -40 C, 10 cycles; T3 7 to 200 Hz 3 h per axis, up to 8 gn; T4 150 gn 6 ms (or 50 gn 11 ms); T5 under 0.1 ohm at 57 C; T6 9.1 kg from 61 cm on 15.8 mm bar; T7 twice max charge; T8 forced discharge. Seals and welds must survive.","applies":["battery","battery pack","energy store"],"basis":"SRC: Report quoting UN Manual Rev.7 sec 38.3; current revision unchecked. F1 also requires the certificate.","sources":["un383-report","fia-2026-c21"],"tags":["un38.3"],"see":["battery-systems/test-un38-3-table"]},{"id":"test-un38-3-table","kind":"test","tier":2,"title":"UN 38.3 test parameters, T1 to T8","summary":"T1 11.6 kPa; T2 72 and -40 C for 10 cycles; T3 7 to 200 Hz, one axis normal to the terminal face; T4 150 gn or 50 gn; T6 13 kN crush for prismatic and pouch cells or cylindrical under 18 mm. Fixture by intended mounts, without distorting cells.","applies":["battery pack","energy store"],"basis":"SRC: Report quoting ST/SG/AC.10/11/Rev.7 sec 38.3. T6 size split read from that revision; earlier text used 20 mm per one secondary page, so check yours.","sources":["un383-report"],"tags":["un38.3"],"value":{"table":[{"test":"T1 altitude","load":"<= 11.6 kPa, >= 6 h"},{"test":"T2 thermal","load":"72 and -40 +/-2 C, >= 6 h each, 30 min max change, 10 cycles"},{"test":"T3 vibration","load":"7-200-7 Hz log sweep 15 min x 12 = 3 h per axis; 1 gn to 8 gn small cells"},{"test":"T4 shock","load":"150 gn 6 ms cells; 50 gn 11 ms large cells"},{"test":"T5 external short","load":"57 +/-4 C, < 0.1 ohm, exterior < 170 C"},{"test":"T6 impact/crush","load":"9.1 kg 61 cm on 15.8 mm bar; or 13 kN crush at 1.5 cm/s"},{"test":"T7 overcharge","load":"2 x max charge current; 1.2 x voltage above 18 V"},{"test":"T8 forced discharge","load":"12 V supply at max discharge current"}]}},{"id":"test-r100-vibration","kind":"test","tier":2,"title":"R100 vibration","summary":"R100 vibration: sine log sweep 7 to 50 to 7 Hz in 15 min, 12 cycles, 3 h vertical; 10 m/s2 to 18 Hz, fading to 2 m/s2 by 30 Hz. Run with SOC in upper 50%. Keep the fundamental mode of pack mounts and busbars out of 7 to 18 Hz.","applies":["battery pack"],"basis":"SRC: UN R100 02 series Annex 8A; a profile agreed for a specific vehicle may replace it. Mode avoidance is EST.","sources":["un-r100-02"],"tags":["r100","vibration"],"value":{"min":7,"max":50,"unit":"Hz"},"see":["standards-testing/test-vibration-sinusoidal-iec-60068-2-6"]},{"id":"test-r100-shock","kind":"test","tier":2,"title":"R100 mechanical shock corridor for cars","summary":"M1/N1 shock pulse: lower corridor plateau 20 g longitudinal, 8 g transverse, from 50 to 65 ms; upper corridor 28 g and 15 g, from 50 to 80 ms, ending at 120 ms. Mount pack and every internal mass for the upper corridor in each direction.","applies":["battery pack"],"basis":"SRC: UN R100 02 series Annex 8C Table 1, read from a two-language extraction. Lighter loads apply for M2/M3. Mounting advice is EST.","sources":["un-r100-02"],"tags":["r100","shock"],"value":{"value":"28 g long, 15 g trans upper","unit":"text"}},{"id":"test-r100-crush","kind":"test","tier":2,"title":"R100 crush and the mounting zone it allows","summary":"R100 component crush: 100 to 105 kN, onset under 3 min, hold 100 ms to 10 s, plate up to 600 x 600 mm. A pack approved this way must mount between planes 420 mm behind the vehicle front edge and 300 mm ahead of the rear edge. Keep crush paths outside cells.","applies":["battery pack","battery enclosure"],"basis":"SRC: UN R100 02 series 6.4.2.2 and Annex 8D. A declared force can replace 100 kN as a mounting restriction. Crush-path sentence is EST.","sources":["un-r100-02"],"tags":["r100","crush"],"value":{"min":100,"max":105,"unit":"kN"}},{"id":"test-propagation-regs","kind":"test","tier":2,"title":"Thermal propagation regulations","summary":"GB 38031-2020: no fire or explosion for 5 min after a trigger cell. GB 38031-2025, from 2026-07-01: none for 2 h, surface at most 60 C, bottom impact 30 mm ball 150 J. R100 05 series: required for new types from 2027-09-01. Barriers now shape the stack.","applies":["battery pack","thermal runaway"],"basis":"SRC: Battery Design summaries, not the texts; dates and figures change, so read the current edition. Immersion 1 m 2 h also listed.","sources":["bd-gb38031","bd-r100"],"tags":["gb38031","propagation","r100"],"value":{"table":[{"rule":"GB 38031-2020","req":"no fire 5 min"},{"rule":"GB 38031-2025","req":"no fire 2 h; surface <= 60 C; 30 mm ball 150 J base impact; 1 July 2026"},{"rule":"UN R100 05 series","req":"in force 26 Sept 2025; new types 1 Sept 2027; all types 1 Sept 2029"}]}},{"id":"test-fmvss-305","kind":"test","tier":2,"title":"FMVSS 305 post-crash requirements","summary":"After 48 km/h frontal, 80 km/h rear, 54 km/h side and static rollover: at most 5.0 L electrolyte spilled outside the cabin and none inside, device retained by an anchor or bracket, no intrusion into occupants. Retention brackets must keep the pack located.","applies":["battery pack"],"basis":"SRC: 49 CFR 571.305 S5, S6. Applies to vehicles at or under 4536 kg GVWR; text marks vehicles manufactured before 2027-09-01, so check successor.","sources":["fmvss-305"],"tags":["fmvss-305","crash","retention"],"value":{"max":5,"unit":"L"}},{"id":"f1-2026-es-limits","kind":"rule","tier":1,"title":"F1 2026 Energy Store headline limits (Issue 21)","summary":"F1 2026 ES: 35.0 kg minimum for the ES Main Enclosure mass group; 4 MJ maximum state-of-charge window on track; 8.5 MJ per lap recharge at CU-K HV bus; maximum working voltage 1000 V; UN 38.3 certificate. Rules change by issue.","applies":["energy store","ers battery"],"basis":"SRC: FIA Section C Issue 21, 2026-10-19, C5.2, C5.17 groups (sub-numbers scrambled in PDF). Mass procedure in FIA-F1-DOC-105, not read.","sources":["fia-2026-c21"],"tags":["f1"],"value":{"min":35,"unit":"kg"}},{"id":"f1-2026-es-volume","kind":"dimension","tier":2,"title":"F1 2026 ERS reference volume RV-PU-ERS","summary":"RV-PU-ERS section at XPU 0, half-car [Y,Z]: [0,1],[240,1],[280,4.1],[280,51],[230,51],[230,380],[0,380], extruded along X to XPU -1500 and trimmed by RS-PU-FWD-ERS. Parts above Z 50 stay aft of RS-FWD-FUEL-LIMIT; at or below Z 50, within 50 mm ahead of it.","applies":["energy store","ers battery"],"basis":"SRC: FIA Section C Issue 21 Appendix C2 sec 3 and C12.2. RS surfaces are defined separately; rule written for +Y and applied symmetrically. ES, CU-K, DC-DC go inside.","sources":["fia-2026-c21"],"tags":["f1","reference-volume"],"value":{"table":[{"Y":0,"Z":1},{"Y":240,"Z":1},{"Y":280,"Z":4.1},{"Y":280,"Z":51},{"Y":230,"Z":51},{"Y":230,"Z":380},{"Y":0,"Z":380}]}},{"id":"f1-2026-es-enclosure","kind":"feature","tier":2,"title":"F1 2026 ES enclosure content and safety","summary":"ESME holds ES, DC sensor, IMD, safety devices, DC-DC, CU-K and HV links; extra items are limited to a list. It needs a gas evacuation system, a fuse close to cells, two contactors, a manual pole isolation and BMS signals alive 15 min after shutdown, off a separate supply.","applies":["energy store","ers battery"],"basis":"SRC: FIA Section C Issue 21, C5.17, C5.20, C5.21 groups. Team designs are not published.","sources":["fia-2026-c21"],"tags":["f1","enclosure"],"value":{"value":"15 min monitoring after shutdown","unit":"text"}},{"id":"formula-e-gen3","kind":"dimension","tier":2,"title":"Formula E Gen3 battery, published figures","summary":"Gen3 (2022-23 season on): 350 kW output, 600 kW maximum regen; battery reported at 284 kg from 385 kg (disputed), 51 kWh planned, 1.9 kW/kg required against 340 W/kg typical; 30 s 600 kW charge adding 4 kWh planned. Single supplier WAE.","applies":["energy store","battery pack"],"basis":"SRC: FE explainer for 350/600 kW; eeNews and Motorsport Technology, 2020-21 pre-launch targets. Motorsport Technology calls 284 kg Gen2 cell weight: sources conflict.","sources":["fe-gen3","eenews-gen3","mt-gen3","race-gen3"],"tags":["formula-e","gen3","motorsport"],"value":{"typical":284,"unit":"kg"}},{"id":"wec-hybrid-batteries","kind":"dimension","tier":2,"title":"WEC and IMSA hybrid battery figures","summary":"Toyota TS050 Hybrid 2016 moved to lithium-ion in the 8 MJ class, 368 kW motors. LMDh spec hybrid running from 2022: WAE battery up to 50 kW continuous, 170 kW regen, Bosch MGU, Xtrac gearbox. Battery kWh and mass unpublished in sources read.","applies":["energy store","battery pack"],"basis":"SRC: Toyota TS050 page; Autosport on LMDh. Current-year regulations not read; these change by year.","sources":["toyota-ts050","autosport-lmdh"],"tags":["wec","lmdh","motorsport"],"value":{"table":[{"car":"Toyota TS050 2016","class_MJ":8,"power_kW":368},{"car":"LMDh spec 2022","cont_kW":50,"regen_kW":170}]}},{"id":"fs-accumulator-limits","kind":"rule","tier":1,"title":"Formula Student accumulator limits 2026","summary":"FS 2026: 600 V max, each segment max 120 V, 6 MJ, 12 kg; 80 kW and 500 A at the container; cells and container mounted for 40 g longitudinal, 40 g lateral, 20 g vertical, inside the primary structure. FSAE 2026 renames parts TBC and modules.","applies":["accumulator","fsae","formula student"],"basis":"SRC: FS Rules 2026 EV 2.2, EV 4.1, EV 5.3, T 3.3; JSAE 2026 guide for the rename. FSAE US text not opened: use the event's own rules.","sources":["fs-rules-2026","jsae-ev-2026"],"tags":["fsae"],"value":{"max":600,"unit":"V"}},{"id":"weld-inspection","kind":"note","tier":2,"title":"Weld pull, X-ray and CT inspection","summary":"Check welds by lap-shear or pull coupons in the joint stack, as in 0.5 mm Al on Hilumin, and by section. Plan coupon-friendly tabs and an X-ray line of sight. No opened source gave a pull-force acceptance or CT resolution limit: set them on the program.","applies":["tab welding"],"basis":"SRC: LJMU 2023 used lap-shear and section microscopy. X-ray line of sight is EST. Acceptance values were not found in any opened source.","sources":["ljmu-hilumin"],"tags":["inspection","pull","ct"]},{"id":"test-eol-isolation","kind":"test","tier":2,"title":"End-of-line isolation and dielectric tests","summary":"FS isolation means 500 ohm/V at max TS voltage or 250 V test, and over 3 times max TS voltage or 750 V RMS for 1 min between circuits. FIA asks ES max plus 1200 V DC on contactors. Clearances must withstand these, so design for the test voltage.","applies":["battery pack","bms"],"basis":"SRC: FS Rules 2026 EV 1.2.1; FIA C5.20 group. Series-production EOL values are not public in sources read.","sources":["fs-rules-2026","fia-2026-c21"],"tags":["eol","hipot","isolation"],"value":{"min":750,"unit":"V"}},{"id":"recipe-21700-holder-plate","kind":"recipe","tier":2,"title":"Recipe: 21700 cell holder plate, 11 cells","summary":"Staggered 4-3-4 holder for P42A-size 21700 cells: 21.9 mm bores at 24.7 mm pitch for a 3 mm cell gap, a 1.5 mm lip with 17 mm weld windows, on an 8 mm plate.","applies":["cell holder","21700"],"basis":"EST: Worked example of cell-21700-envelope, cell-gap-propagation and cell-holder-plate. Bore fit and lip are not from a standard.","sources":["molicel-p42a","nasa-darcy-2015"],"tags":["recipe","holder"],"recipe":{"prompt":"Model a 21700 cell holder plate for 11 cells with a 3 mm gap between cells and weld windows","steps":[{"tool":"cad_extrude_profile","args":{"depth":1.5,"outer":{"rect":{"x":0,"y":0,"w":104,"h":73,"cornerRadius":4}},"holes":[{"circle":{"cx":-37.05,"cy":-21.391,"r":8.5}},{"circle":{"cx":-12.35,"cy":-21.391,"r":8.5}},{"circle":{"cx":12.35,"cy":-21.391,"r":8.5}},{"circle":{"cx":37.05,"cy":-21.391,"r":8.5}},{"circle":{"cx":-24.7,"cy":0,"r":8.5}},{"circle":{"cx":0,"cy":0,"r":8.5}},{"circle":{"cx":24.7,"cy":0,"r":8.5}},{"circle":{"cx":-37.05,"cy":21.391,"r":8.5}},{"circle":{"cx":-12.35,"cy":21.391,"r":8.5}},{"circle":{"cx":12.35,"cy":21.391,"r":8.5}},{"circle":{"cx":37.05,"cy":21.391,"r":8.5}}]},"note":"retaining lip with dia 17 weld windows at hex pitch 24.7"},{"tool":"cad_extrude_profile","args":{"depth":6.5,"outer":{"rect":{"x":0,"y":0,"w":104,"h":73,"cornerRadius":4}},"holes":[{"circle":{"cx":-37.05,"cy":-21.391,"r":10.95}},{"circle":{"cx":-12.35,"cy":-21.391,"r":10.95}},{"circle":{"cx":12.35,"cy":-21.391,"r":10.95}},{"circle":{"cx":37.05,"cy":-21.391,"r":10.95}},{"circle":{"cx":-24.7,"cy":0,"r":10.95}},{"circle":{"cx":0,"cy":0,"r":10.95}},{"circle":{"cx":24.7,"cy":0,"r":10.95}},{"circle":{"cx":-37.05,"cy":21.391,"r":10.95}},{"circle":{"cx":-12.35,"cy":21.391,"r":10.95}},{"circle":{"cx":12.35,"cy":21.391,"r":10.95}},{"circle":{"cx":37.05,"cy":21.391,"r":10.95}}]},"note":"cell pocket layer, dia 21.9 bores (P42A dia 21.7 max + 0.2)"},{"tool":"cad_transform","args":{"of":"$1","translate":[0,0,1.5]},"note":"seat the pocket layer on the lip"},{"tool":"cad_boolean_union","args":{"of":"$0","tool":"$2"},"note":"one holder plate, 8 mm total"}],"expect":{"volume":29947.99,"faceCount":47,"watertight":true,"note":"measured 2026-11-04: first pin"}}},{"id":"recipe-copper-busbar","kind":"recipe","tier":2,"title":"Recipe: bolted copper busbar, 60 mm2","summary":"A 100 x 20 x 3 mm copper bar with two dia 8.5 M8 clearance holes at 75 mm centres, 60 mm2 section so about 300 A at the 5 A/mm2 starting figure, with 12.5 mm end land for a 15 to 30 mm overlap.","applies":["busbar"],"basis":"EST: Worked example of busbar-current-density and busbar-bolted-overlap. Hole from the M8 clearance convention in hardware.","sources":["bd-busbars"],"tags":["recipe","busbar"],"see":["hardware/clearance-holes-metric"],"recipe":{"prompt":"Model a 300 A copper busbar with two M8 bolt holes","steps":[{"tool":"cad_extrude_profile","args":{"depth":3,"outer":{"rect":{"x":0,"y":0,"w":100,"h":20,"cornerRadius":3}},"holes":[{"circle":{"cx":-37.5,"cy":0,"r":4.25}},{"circle":{"cx":37.5,"cy":0,"r":4.25}}]},"note":"60 mm2 section, M8 clearance holes"}],"expect":{"volume":5636.35,"faceCount":14,"watertight":true,"note":"measured 2026-11-04: first pin"}}},{"id":"recipe-module-end-plate","kind":"recipe","tier":2,"title":"Recipe: PHEV2 module end plate","summary":"Aluminium end plate 168 x 111 x 16 mm for a PHEV2 stack: four dia 9 tie-rod holes outside the 148 x 91 cell face, two M6 mount holes, and two 4 mm pockets outside the cell-face centre to save mass.","applies":["end plate","prismatic cell"],"basis":"EST: Illustrates swell-clamp-load-phev2 and end-plate-tie-rods. 16 mm thickness is an unverified start: check with cad_fea_case at 50 kN.","sources":["bd-expansion","bd-vda"],"tags":["recipe","end-plate"],"recipe":{"prompt":"Model an aluminium end plate for a PHEV2 cell stack with four tie-rod holes","steps":[{"tool":"cad_extrude_profile","args":{"depth":16,"outer":{"rect":{"x":0,"y":0,"w":168,"h":111,"cornerRadius":5}},"holes":[{"circle":{"cx":-78,"cy":-49.5,"r":4.5}},{"circle":{"cx":78,"cy":-49.5,"r":4.5}},{"circle":{"cx":-78,"cy":49.5,"r":4.5}},{"circle":{"cx":78,"cy":49.5,"r":4.5}},{"circle":{"cx":0,"cy":49.5,"r":3.3}},{"circle":{"cx":0,"cy":-49.5,"r":3.3}}]},"note":"plate with tie-rod and mount holes"},{"tool":"cad_box","args":{"dx":44,"dy":60,"dz":5,"origin":[-66,-30,12]},"note":"left outer-face pocket tool, 4 mm deep"},{"tool":"cad_boolean_subtract","args":{"of":"$0","tool":"$1"},"note":"cut the left pocket"},{"tool":"cad_box","args":{"dx":44,"dy":60,"dz":5,"origin":[22,-30,12]},"note":"right outer-face pocket tool"},{"tool":"cad_boolean_subtract","args":{"of":"$2","tool":"$3"},"note":"cut the right pocket; centre rib stays over the cell face"}],"expect":{"volume":271738.35,"faceCount":26,"watertight":true,"note":"measured 2026-11-04: first pin"}}},{"id":"recipe-cold-plate-channels","kind":"recipe","tier":2,"title":"Recipe: cold plate base with parallel channels","summary":"Aluminium cold plate base 200 x 100 x 8 mm with three 12 mm wide, 170 mm long, 4 mm deep channels, to take a brazed cover and manifolds. Channel depth is a placeholder for your flow and pressure-drop solution.","applies":["cold plate"],"basis":"EST: Geometry illustrates cold-plate-channel; no published depth backs 4 mm. Run a flow calculation before use.","sources":["ugm-coldplate"],"tags":["recipe","cold-plate"],"recipe":{"prompt":"Model a cold plate base with three parallel coolant channels","steps":[{"tool":"cad_extrude_profile","args":{"depth":8,"outer":{"rect":{"x":0,"y":0,"w":200,"h":100,"cornerRadius":4}}},"note":"plate base"},{"tool":"cad_extrude_profile","args":{"depth":5,"outer":[[-85,-6],[85,-6],[85,6],[-85,6]],"holes":[]},"note":"channel tool, 12 x 170"},{"tool":"cad_transform","args":{"of":"$1","translate":[0,0,4]},"note":"raise channel tool so it cuts 4 mm from the top face"},{"tool":"cad_boolean_subtract","args":{"of":"$0","tool":"$2"},"note":"centre channel"},{"tool":"cad_box","args":{"dx":170,"dy":12,"dz":5,"origin":[-85,24,4]},"note":"upper channel tool"},{"tool":"cad_boolean_subtract","args":{"of":"$3","tool":"$4"},"note":"upper channel"},{"tool":"cad_box","args":{"dx":170,"dy":12,"dz":5,"origin":[-85,-36,4]},"note":"lower channel tool"},{"tool":"cad_boolean_subtract","args":{"of":"$5","tool":"$6"},"note":"lower channel"}],"expect":{"volume":135410.12,"faceCount":25,"watertight":true,"note":"measured 2026-11-04: first pin"}}}]}