Battery Module End Plate with Variable Beam Width
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Solution Overview
Problem
Battery modules for electric vehicles face increased cell thickness restraint reaction forces due to higher energy density and active material packing, leading to concerns about weight gain from rigid end plates.
Innovation Solution
The design incorporates end plates with column and beam portions, where the central beam portions have greater width than the end portions, and hollow portions to increase rigidity while reducing weight, and connection frames that allow relative displacement to manage stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If end plates with high rigidity are used to receive cell thickness restraint reaction force, then the structural strength is improved, but the weight of the end plate and battery module increases significantly
Solution Approach 1:
The end plate features varying thickness distribution where the central portion has greater thickness than the end portions. This local quality variation concentrates material where bending stress is highest (central region) while reducing material in low-stress areas (end regions), thereby maintaining structural strength while minimizing weight.
Solution Approach 2:
The end plate is segmented into multiple regions with different thickness characteristics - a thicker central portion and thinner end portions. This segmentation allows the structure to optimize material distribution according to the stress profile, placing material only where mechanically necessary.
2Quantity of substance
If cell capacity and energy density are increased by packing more active material, then the energy storage capability is improved, but the cell thickness restraint reaction force increases
Solution Approach 1:
The end plate thickness distribution is changed as a parameter to match the stress distribution pattern. By making the central portion thicker and end portions thinner, the plate's mechanical properties are optimized to handle the increased forces generated by high-capacity cells without requiring uniform thickness throughout.
Data Source
AI summary
A battery module includes: a cell stack which is constituted by stacking a plurality of cells, and includes a first surface, a second surface, a third surface, a fourth surface, a fifth surface, and a sixth surface; a pair of end plates which are disposed on the first surface and the second surface of the cell stack; and a pair of connection frames which connect the pair of end plates. The pair of end plates each includes: a plurality of column portions; a plurality of beam portions; and hollow portions formed by the column portions and the beam portions. The pair of the end plates each has a uniform width in a stacking direction. In at least one beam portion of the plurality of beam portions, a width of a central portion is greater than a width of both end portions.