Composite End Plate Structure for Rigid Lightweight Battery Modules
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Solution Overview
Problem
Battery modules require increased rigidity to manage dimensional variations caused by swollen batteries while minimizing size and weight increments, as traditional welded structures restrict material choices and lead to increased dimensions and weight.
Innovation Solution
A battery module design featuring end plates with a first metal portion for high Young's modulus and a second metal portion for low density, combined with restraint members made of high Young's modulus metal, connected via welded portions to enhance rigidity without increasing size or weight, using a combination of metals like iron and aluminum or magnesium alloys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of batteries is increased to output high voltage, then power output is improved, but dimensional variation increases due to swollen batteries
Solution Approach 1:
The end plate is segmented into two portions: a first portion made of high Young's modulus metal (e.g., iron-based) for rigidity, and a second portion made of low density metal (e.g., aluminum or magnesium alloy) for weight reduction. This segmentation allows each portion to fulfill its specific function optimally.
Solution Approach 2:
The end plate uses a composite structure combining two different metals with complementary properties. The first metal provides high rigidity to suppress dimensional variation from battery swelling, while the second metal reduces overall weight, achieving both goals simultaneously.
2Manufacturing precision
If rigidity of the battery module is increased to suppress dimensional variation, then dimensional stability is improved, but size and weight increase
Solution Approach 1:
Different portions of the end plate have different material qualities: the first portion (contacting restraint member) uses high Young's modulus metal for local rigidity where needed, while the second portion uses low density metal to minimize weight, achieving dimensional stability without excessive weight gain.
Solution Approach 2:
The composite end plate structure combines high rigidity material where structural support is needed with low density material in other areas, optimizing the balance between dimensional stability and weight reduction.
3Strength
If welded structure is used to connect end plates to fastening member, then connection strength is improved, but material selection is restricted
Solution Approach 1:
The invention changes the material parameter of the end plate by using a composite structure of two different metals, enabling welding compatibility between the first portion and the restraint member while maintaining overall design flexibility and strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively increases the rigidity of the battery module, reduces dimensional variations, and maintains a compact size and weight, enhancing energy density and thermal insulation while minimizing heat transfer during welding.
Implementation Method 1
a welded portion that connects the first portion of the at least one end plate with the restraint member
Data Source
AI summary
A battery module includes: a battery stack that includes a plurality of batteries stacked; a pair of end plates that are disposed at both ends, in stack direction X in which the batteries are stacked, of the battery stack, the pair of end plates including at least one end plate that includes a first portion made of a first metal that has a Young's modulus higher than a Young's modulus of a second metal, and a second portion made of the second metal that has a density lower than a density of the first metal; a restraint member that is made of the first metal and sandwiches the battery stack and the pair of end plates in stack direction X; and a welded portion that connects the first portion of the at least one end plate with the restraint member.