Gradient Electrochemical Cell Arrays for Swelling Pressure Balance
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Solution Overview
Problem
Larger electrochemical cell assemblies in devices like electric vehicles face challenges due to varying operating conditions among cells, such as temperature differences and swelling, which can lead to uneven expansion and increased pressure, particularly in central and edge cells.
Innovation Solution
The implementation of electrochemical cell arrays with cells of varying sizes and thicknesses arranged in asymmetrical or symmetrical gradients to mitigate uneven stress and pressure, using interconnects for electrical communication among cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If larger electrochemical cell assemblies are used to meet high energy demands, then energy storage capacity is improved, but stress and pressure disparities among cells increase due to varying operating conditions
Solution Approach 1:
The patent applies local quality by varying the thickness of individual cells within the assembly based on their position. Central cells are made thinner while outer cells are made thicker, creating localized differences in cell properties that compensate for the varying stress and temperature conditions experienced at different positions in the assembly. This non-uniform thickness distribution optimizes each cell's performance under its specific local operating conditions.
Solution Approach 2:
The patent employs asymmetry by deliberately creating an asymmetric thickness distribution among cells in the assembly. Rather than using uniform cell dimensions, the design incorporates cells with different thicknesses arranged in a non-uniform pattern, where the thickness varies based on position within the assembly. This asymmetric configuration helps balance the overall stress and pressure distribution across the entire battery assembly.
2Power
If cells are arranged in larger assemblies, then energy demand is met, but temperature differences and swelling variations among cells increase
Solution Approach 1:
The patent addresses temperature differences by applying local quality through position-dependent cell thickness variation. Cells in different locations within the assembly have different thicknesses tailored to their specific thermal environments. This localized optimization helps equalize temperature distribution across the assembly by compensating for the varying thermal conditions at different positions.
3Ease of manufacture
If uniform cell sizes are used in the assembly, then manufacturing is simplified, but uneven expansion and increased pressure occur during operation
Solution Approach 1:
The patent resolves the contradiction between manufacturing simplicity and uniform expansion by applying local quality. Instead of using uniform cell sizes, the design incorporates cells with different thicknesses at different positions within the assembly. This localized variation in cell dimensions compensates for the uneven expansion that would otherwise occur, maintaining overall assembly stability while still being manufacturable through standardized processes.
Solution Approach 2:
The patent uses asymmetry to achieve uniform expansion behavior in the overall assembly. By deliberately designing cells with asymmetric thickness distributions based on their positions, the system compensates for the non-uniform expansion that would naturally occur in uniform cell assemblies. This asymmetric configuration ensures more uniform overall expansion and pressure distribution during operation.
Data Source
AI summary
Electrochemical cell arrays such as battery packs having cells of different sizes and/or thicknesses is disclosed. For example, the cells in an array may progressively increase or decrease in size or thickness from a first end to a second end such that a gradient in thickness is created. Alternatively, the gradient may be from the center to the outside. In a variation, the first and second endplates may be of different sizes or thicknesses.