Prismatic Battery Cell Separator Bonding for Reduced Overhang
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Solution Overview
Problem
Existing secondary prismatic battery cell designs face challenges in achieving high energy storage density due to issues with separator overhang and manufacturing robustness, leading to potential shorting and bridging problems.
Innovation Solution
A secondary battery cell design with a separator that has an adhesive strip applied only on the cathode-facing side, bonded to itself at specific locations, reducing separator overhang and enhancing the electrode assembly's robustness, while maintaining low resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If separator overhang is reduced to maximize electrode size, then volumetric energy density is improved, but manufacturing robustness deteriorates leading to potential shorting and bridging problems
Solution Approach 1:
An adhesive strip is applied to the separator in advance during manufacturing, before the electrode assembly is completed. This preliminary action ensures that the separator remains stable and prevents shorting/bridging issues that would otherwise occur when separator overhang is reduced to maximize electrode size and energy density.
2Reliability
If adhesive strip is applied on separator to improve manufacturing robustness, then reliability is improved, but device complexity increases
Solution Approach 1:
The adhesive strip is applied locally only to specific areas of the separator where needed for manufacturing robustness, rather than covering the entire separator. This localized approach improves reliability during assembly while minimizing the increase in overall device complexity and maintaining energy density benefits.
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 design achieves increased energy density by maximizing electrode size without increasing cell resistance, improving volumetric energy density from 673 Wh/L to 677 Wh/L and energy content from 556.9 Wh to 560 Wh, benefiting vehicle mileage and reducing battery pack size.
Implementation Method 1
an adhesive strip applied solely on the cathode-facing side of the separator. The adhesive strip resides completely in the bonding area. Two segments of the adhesive strip on opposing sides of the cathode are bonded to each other.
Data Source
AI summary
A secondary battery cell includes a battery cell enclosure, an electrolyte, and an electrode assembly. The electrode assembly includes a cathode with a cathode area, an anode, a separator (i) with an anode-facing side and a cathode-facing side, (ii) with a bonding area on the cathode-facing side and completely outside the cathode area, and (iii) configured to physically separate the cathode and the anode, and an adhesive strip applied solely on the cathode-facing side of the separator. The cathode is either partially enclosed or completely enclosed by the separator. The adhesive strip is completely in the bonding area. Two segments of the adhesive strip on opposing sides of the cathode are bonded to each other.