Traction Battery Pack Compression Wall for Cell Expansion Control
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Solution Overview
Problem
Conventional traction battery pack assemblies face challenges in efficiently compressing and securing battery cells, leading to potential instability and reduced performance due to the lack of effective compressive forces and expansion accommodation within the enclosure structure.
Innovation Solution
The method involves positioning cell stacks within an enclosure structure, applying a compressive force using a compressing wall, and securing it to maintain the cell stacks, while utilizing separator plates with compressible materials to allow for expansion, and integrating a Battery Energy Control Module within the assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional battery pack assemblies use simple enclosure structures without compressing walls, then the device complexity is reduced, but the stability and performance of battery cells deteriorate due to lack of effective compressive forces
Solution Approach 1:
The enclosure structure is segmented into a base enclosure and a separate compressing wall assembly. The compressing wall is positioned within the enclosure to contact and compress the battery cells, while the base enclosure provides structural support and housing. This segmentation allows the compressing function to be added without completely redesigning the entire enclosure structure.
Solution Approach 2:
The compressing wall is pre-configured with compressible material and positioning features before being integrated into the battery pack assembly. This preliminary preparation ensures that when the compressing wall is installed, it automatically applies the necessary compressive force to the battery cells without requiring additional adjustment or complex mounting mechanisms.
2Strength
If rigid separator plates are used between battery cells, then the structural strength is improved, but the ability to accommodate expansion deteriorates
Solution Approach 1:
The separator plates are constructed as composite structures combining rigid framing elements with compressible material. The rigid frame provides structural strength to maintain cell spacing and prevent collapse, while the compressible material filling the frame allows the separator plate to deform and accommodate battery cell expansion during charging cycles.
Solution Approach 2:
Different regions of the separator plate have different mechanical properties. The frame portions are made rigid to provide structural support, while the central compressible material regions are made flexible to allow expansion. This local differentiation of material properties enables the separator plate to simultaneously provide strength and expansion accommodation.
3Quantity of substance
If battery cells are tightly packed without expansion space, then the energy density is improved, but the reliability deteriorates due to potential expansion damage
Solution Approach 1:
The compressing wall incorporates compressible material that acts as a flexible element between the rigid enclosure structure and the battery cells. This flexible component allows the battery cells to expand slightly during charging without causing damage, while maintaining tight packing to maximize energy density. The compressible material deforms to accommodate expansion and then returns to its original shape.
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
This approach enhances the stability and performance of battery cells by ensuring consistent compressive forces and accommodating expansion, thereby improving the overall efficiency and reliability of the traction battery pack assembly.
Implementation Method 1
moving a compressing wall against the at least one cell stack to a position where the compressing wall applies a compressive force to the at least one cell stack between the enclosure structure and the compressing wall
Implementation Method 2
the at least one cell stack includes plurality of separator plates that each include a frame about a compressible material, the compressible material configured to permit expansion of the battery cells within the at least one cell stack
Data Source
AI summary
A battery pack assembly method, including: positioning at least one cell stack within an enclosure structure; moving a compressing wall against the at least one cell stack to a position where the compressing wall applies a compressive force to the at least one cell stack between the enclosure structure and the compressing wall; and securing the compressing wall to hold the at least one cell stack in the position.