Prismatic Battery Collector Rib Height Compensation
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Solution Overview
Problem
When forming a battery pack from prismatic secondary batteries with differing positive and negative electrode substrate thicknesses, the uneven rib heights on the collectors lead to non-uniform compression, resulting in varied battery pack length and potential bending issues.
Innovation Solution
The prismatic secondary battery design features collectors with ribs of varying heights to match the positive and negative electrode substrates' thickness differences, ensuring equal rib leading ends and uniform compression during packing, thereby maintaining battery pack stability and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If collectors with ribs of the same height are used, then the manufacturing process is simple, but the battery pack exhibits non-uniform compression and bending when electrode substrates have different thicknesses
Solution Approach 1:
The patent applies local quality by making the rib heights different on the positive and negative collectors to match the different thicknesses of the electrode substrates. Specifically, when the positive electrode substrate is thicker than the negative electrode substrate, the rib on the positive collector is made taller than the rib on the negative collector, ensuring that the leading ends of both ribs align at the same height. This local differentiation in rib height compensates for the thickness difference and achieves uniform compression across the battery pack.
2Reliability
If electrode substrates of different thicknesses are used, then the battery capacity and output characteristics are optimized, but the battery pack length and uniformity deteriorate
Solution Approach 1:
The patent changes the geometric parameter of the collector ribs (height) to compensate for the thickness difference between electrode substrates. By adjusting the rib height according to the substrate thickness difference, the overall compression uniformity is maintained, preventing variation in battery pack length and bending even when using electrode substrates of different thicknesses for optimized capacity and output characteristics.
3Reliability
If non-uniform compression is applied, then the assembly process is simpler, but internal short circuits may occur and electrical insulation deteriorates
Solution Approach 1:
The patent implements preliminary action by pre-designing the rib heights on the collectors before assembly to account for the thickness difference between electrode substrates. This pre-planned differentiation in rib height ensures that when compression is applied during assembly, the force is distributed uniformly across both positive and negative electrodes, preventing internal short circuits and maintaining electrical insulation without requiring complex compression control during the manufacturing process.
Data Source
AI summary
A prismatic secondary battery includes a flat electrode assembly including one end having stacked positive electrode substrate exposed portions and including the other end having stacked negative electrode substrate exposed portions, and includes a positive electrode collector and a negative electrode collector connected to the corresponding outermost surface in the stacking direction of the stacked positive electrode substrate exposed portions and the stacked negative electrode substrate exposed portions, respectively, by resistance welding; the positive electrode substrate and the negative electrode substrate have thicknesses different from each other; a rib of the positive electrode collector and a rib of the negative electrode collector have heights different from each other; and each leading end in the height direction of the ribs has approximately the same height.