Battery Module Buffer Structure for Cell Thermal Expansion
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Solution Overview
Problem
Existing battery packs fail to absorb the thermal expansion of battery cells, leading to potential mechanical stress and reliability issues.
Innovation Solution
A battery module design that includes a buffer member disposed between battery cells and the case, with a thickness direction coinciding with the array direction of the battery cells. The buffer member is formed such that the reaction force acting on the battery cells is smaller at the central portion than at the peripheral end portion, allowing for uniform absorption of thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If battery cells are arrayed without gaps to improve storage density, then the amount of stored charge per unit area increases, but thermal expansion of battery cells cannot be absorbed
Solution Approach 1:
The buffer member is divided into a first buffer portion and a second buffer portion positioned at different locations (between adjacent battery cells and between battery cells and case inner wall, respectively). This segmentation allows the buffer to address thermal expansion at multiple critical points simultaneously, maintaining both high storage density and reliability.
Solution Approach 2:
The buffer member has different thicknesses at different locations: the first buffer portion has a first thickness while the second buffer portion has a second thickness greater than the first. This local quality variation provides stronger buffering capacity where needed (at the case interface) while maintaining compactness in other areas, resolving the contradiction between space efficiency and expansion absorption.
2Reliability
If buffer members are added to absorb thermal expansion, then reliability improves, but device complexity increases
Solution Approach 1:
The single buffer member performs multiple functions: it provides thermal expansion buffering between adjacent battery cells (first buffer portion) and between battery cells and the case inner wall (second buffer portion). This multi-functionality reduces the need for multiple separate components, thereby improving reliability without proportionally increasing device complexity.
Solution Approach 2:
The buffer member's thickness parameter is strategically varied at different locations (first thickness vs. second thickness). This parameter change allows the same component to provide differentiated buffering capacity where needed, achieving complex functional requirements through a single part rather than multiple components.
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 proposed solution effectively absorbs thermal expansion of battery cells, reducing mechanical stress and improving the overall reliability of the battery pack by ensuring uniform reaction forces across the battery cells.
Implementation Method 1
the central parts of the battery cells swell in their thickness direction during thermal expansion
Implementation Method 2
a buffer member that is disposed at least one of between adjacent battery cells or between the battery cells and an inner wall of the case
Data Source
AI summary
A battery module includes: a plurality of battery cells housed in an arrayed state inside a case; and a buffer member that is disposed at least one of between adjacent battery cells and between the battery cells and an inner wall of the case such that its thickness direction coincides with the array direction of the battery cells and is formed in such a way that a reaction force acting on the battery cells is smaller at its central portion than at its peripheral end portion.