Battery Cell Buffer Structure for Uneven Expansion Force Control
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Solution Overview
Problem
Uneven distribution of expansion forces on the side surfaces of electrode assemblies in battery cells leads to lithium precipitation, affecting cycling performance and service life.
Innovation Solution
A battery cell design incorporating a buffer member with a first buffer portion and a second buffer portion, where the first buffer portion covers the central region and has a greater compression amount than the second buffer portion, which covers the edge region, to mitigate uneven expansion forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a buffer member with uniform compression properties is used, then the structure is simple, but the expansion force distribution remains uneven causing lithium precipitation
Solution Approach 1:
The buffer member is designed with different compression properties in different regions: the first buffer portion (central region) has higher compressibility with compression amount of 0.8mm-1.5mm, while the second buffer portion (edge region) has lower compressibility with compression amount of 0.3mm-0.8mm. This local differentiation allows each region to independently buffer expansion forces appropriately, preventing lithium precipitation while maintaining structural integrity.
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
Reduces the difference in expansion forces between the central and edge regions, minimizing lithium precipitation and enhancing cycling performance and service life of the battery cell.
Implementation Method 1
Under a same pressure, a compression amount of the first buffer portion is greater than a compression amount of the second buffer portion
Implementation Method 2
the first buffer portion more easily deformed under compression compared to the second buffer portion
Data Source
AI summary
A battery cell, a battery, and an electric apparatus. The battery cell includes an outer shell, an electrode assembly, and a buffer member in a mounting cavity of the outer shell. The electrode assembly is in the cavity with side surfaces extending in a thickness direction. The buffer member includes a first buffer portion and a second buffer portion, where the first buffer portion has at least one edge portion connected to the second buffer portion. The first buffer portion at least partially covers a central region of the side surfaces, and the second buffer portion covers an edge region of the side surfaces. Under the same pressure, the first buffer portion deforms more readily than the second buffer portion, thereby reducing expansion forces at the central region relative to the edge region, mitigating uneven force distribution, and improving cycling performance and service life of the battery cell.