How a Tier 1 EV supplier replaced an injection molded battery tray with heavy gauge thermoforming — meaningful weight savings, lower tooling investment, and a faster path to first production parts.
BRT USA Engineering Team · Automotive Programs
Published July 9, 2026
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This case study documents a real EV battery tray program where a Tier 1 supplier needed a lighter, faster-to-market alternative to an injection molded structural tray. Heavy gauge forming delivered meaningful gains in weight, cost, and schedule — without sacrificing crash performance requirements.
Program background
The customer was developing a battery module tray for a 2027-model electric vehicle platform. The initial injection molded HDPE design met stiffness targets but exceeded the weight budget and required a steel mold lead time that did not fit the compressed SOP schedule. Engineering asked whether heavy gauge thermoforming could meet structural requirements at lower mass and tooling cost.
Design and material approach
BRT USA engineering collaborated on a DFM review of the tray geometry. The redesigned part used 0.250" PC/ABS sheet formed into a ribbed female cavity, with mounting bosses and seal surfaces CNC-trimmed after forming. Rib height and spacing were optimized in FEA to match the prior injection molded stiffness while eliminating solid sections that added unnecessary mass.
Material: flame-retardant PC/ABS, UL94 V-0 rated at specified thickness
Forming: single-cavity aluminum tool with plug assist for deep rib draws
Trim: 5-axis CNC for perimeter, mount holes, and seal groove
Secondary: adhesive foam gasket applied in assembly (not formed in)
Results and metrics
Before vs after — EV battery tray
Injection molded (baseline)
Higher part weight than target. Steel injection mold with a longer typical lead time. Part met stiffness but missed weight target.
Heavy gauge thermoformed (final)
Lower part weight than the injection molded baseline in this program. Aluminum forming + trim fixture with shorter typical lead time. Lower tooling investment. Stiffness and drop-test criteria met.
First production parts shipped ahead of the injection molding timeline projected for this program. PPAP was completed on a typical automotive validation timeline before SOP. The customer carried thermoforming into SOP and retained the option to increase cavity count on a second tool if volume grew beyond single-cavity capacity.
Lessons for EV thermoforming programs
Early engagement between OEM engineering and the thermoformer is critical for EV structural parts. Weight targets are easier to hit when rib geometry and sheet gauge are co-optimized before tooling. Thermoforming also allows faster design iterations — aluminum tool modifications for minor geometry changes cost far less than injection mold rework.
Can thermoformed trays meet EV crash and stiffness requirements?
Yes, when rib geometry, material grade, and wall thickness are engineered for the load case. PC/ABS and reinforced grades are common for battery enclosures. Validation through FEA and physical drop testing is standard on automotive programs.
How does tooling cost compare to injection molding for EV trays?
For large structural trays, heavy gauge aluminum tooling is often substantially less than comparable injection mold cost in programs of similar size, with shorter typical lead times. Economics often favor thermoforming at moderate annual volumes where part size drives injection mold cost up.
What lead time should we plan for a thermoformed EV battery tray?
Prototype parts from bridged tooling: often a few weeks. Production aluminum tool with CNC trim fixture: often roughly two to three months from design freeze, depending on complexity. PPAP and process validation add additional time based on customer requirements.
Is this case study from a real BRT USA program?
This case study is representative of automotive EV programs BRT USA supports. Specific customer and vehicle details are anonymized. Contact us for references on current automotive thermoforming work.