Battery Cell Restraint Structure for Thinner End Plates
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Solution Overview
Problem
Conventional battery assemblies face challenges in balancing the need for increased proof strength of end plates to withstand moment loads due to battery expansion while also reducing the thickness for downsizing.
Innovation Solution
A battery assembly design where the end plate is restrained by a pair of members sandwiching the battery cells in a direction orthogonal to the long-side direction, with a contact plate abutting a stepped portion, allowing for reduced thickness and improved load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the end plate is increased to enhance proof strength for receiving moment load, then the strength is improved, but the size of the battery assembly increases
Solution Approach 1:
The restraint structure is segmented into multiple functional components: end plates at both ends, restraint members extending between them, and support members connecting the restraint members to the battery cell cases. This segmentation distributes the moment load across multiple elements rather than concentrating it on the end plates alone, allowing thinner end plates while maintaining overall structural strength.
Solution Approach 2:
The support members extend in the width direction (second direction) to connect the restraint members to the battery cell cases, creating a three-dimensional load distribution network. This dimensional approach transforms the moment load resistance from a two-dimensional end plate problem into a three-dimensional structural system, reducing the thickness requirement of individual end plates.
2Reliability
If the thickness of the end plate is increased to withstand expansion force, then the reliability is improved, but the weight of the assembly increases
Solution Approach 1:
The restraint structure divides the load-bearing function across multiple components including end plates, restraint members, and support members. Each component can be optimized for its specific function, allowing the end plates to be thinner and lighter while the overall structure maintains reliability through the distributed load path provided by the segmented architecture.
3Stability of the object's composition
If conventional restraint structures are used, then the battery cells are restrained, but the moment load on the end plate becomes excessively large
Solution Approach 1:
The support members extend in the width direction to connect the restraint members to the battery cell cases, creating a three-dimensional load distribution network. This dimensional approach transforms the moment load resistance from a two-dimensional end plate problem into a three-dimensional structural system, reducing the thickness requirement of individual end plates.
Solution Approach 2:
The restraint structure is segmented into multiple functional components: end plates at both ends, restraint members extending between them, and support members connecting the restraint members to the battery cell cases. This segmentation distributes the moment load across multiple elements rather than concentrating it on the end plates alone, allowing thinner end plates while maintaining overall structural strength.
Data Source
AI summary
Each of a plurality of battery cells included in a battery assembly includes a case that accommodates an electrode assembly and that has a substantially rectangular shape in which a second direction orthogonal to a first direction corresponds to a long-side direction and a third direction orthogonal to the first direction and the second direction corresponds to a short-side direction when viewed in the first direction. A restraint member includes a pair of members provided to sandwich the plurality of battery cells in the third direction, and the pair of members are fixed to the end plate in the third direction.