Prismatic Battery Spacer Design for Electrode Displacement Control
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Solution Overview
Problem
Conventional prismatic batteries experience non-uniform expansion and shrinkage during charging and discharging, leading to uneven deterioration of electrodes and reduced capacity and output due to inadequate reaction force from the case against electrode displacement.
Innovation Solution
An energy storage apparatus with a spacer design where the center portion's thickness in one direction is larger than other portions, and the width at the contact portion is smaller than the case, ensuring a continuous reaction force is applied to the electrode assembly, minimizing electrode displacement during expansion and deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional prismatic case is used with uniform thickness, then the manufacturing is simple and cost-effective, but the case cannot provide sufficient reaction force against electrode expansion during charging and discharging cycles
Solution Approach 1:
The case is designed with non-uniform thickness where the center portion has a smaller thickness than the end portions. This local variation in thickness creates a rigidity distribution that concentrates reaction force at the center where electrode expansion occurs most, while maintaining structural integrity through thicker end portions.
Solution Approach 2:
The case structure transitions from a uniform two-dimensional plate to a three-dimensional form with varying thickness. This dimensional change allows the case to provide targeted mechanical support at specific locations without requiring a complete structural redesign.
2Strength
If the case rigidity is increased uniformly throughout, then the reaction force against electrode expansion improves, but the manufacturing complexity and cost increase
Solution Approach 1:
Instead of uniformly increasing case rigidity throughout, the invention applies increased rigidity only where needed - at the center portion where electrode expansion is most significant. The end portions maintain standard thickness, simplifying manufacturing while providing targeted mechanical support.
Solution Approach 2:
The case provides excessive rigidity (thicker material) only at the center portion where it is most needed, rather than uniformly throughout. This partial application of increased rigidity achieves the required mechanical support while minimizing manufacturing complexity and material usage.
3Manufacturing precision
If the spacer center portion thickness is increased, then the reaction force distribution becomes more uniform, but the spacer manufacturing complexity increases
Solution Approach 1:
The spacer is designed with non-uniform thickness where the center portion has a larger thickness than the end portions. This local variation in thickness compensates for the natural rigidity distribution, ensuring uniform reaction force application across the electrode assembly while maintaining a relatively simple single-piece structure.
Data Source
AI summary
An energy storage apparatus includes: an energy storage device including a flat electrode assembly in which electrodes are layered and a prismatic case in which the electrode assembly is housed; and a spacer arranged adjacently to the energy storage device in a first direction, wherein the spacer is formed such that a thickness size in the first direction of a center portion of the spacer in a second direction, which is a direction orthogonal to the first direction and is a direction parallel to a surface of the spacer that faces the energy storage device, is set larger than a thickness size in the first direction of other portions of the spacer arranged adjacently to the center portion of the spacer in the second direction, and a width of the center portion of the spacer in a third direction orthogonal to the first and second directions at a contact portion of the spacer with the energy storage device is set smaller than a width of the case in the third direction.