Secondary Battery Vertical Electrode Assembly Swelling Management
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Solution Overview
Problem
Conventional secondary batteries face challenges in managing cell swelling and ensuring durability, particularly in designs with multiple electrode assemblies, where stress concentration and inertial mass can lead to increased swelling and reduced durability.
Innovation Solution
The design features multiple electrode assemblies arranged vertically within a case, with differently sized upper and lower assemblies, and a current collector configuration that includes protruding parts inserted into the winding core for enhanced electrical connection and reduced resistance, along with insulating members to prevent electrical shorts and moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple electrode assemblies are arranged vertically in the case, then the battery capacity is increased, but the cell swelling increases due to stress concentration and inertial mass
Solution Approach 1:
The battery is divided into multiple electrode assemblies (first, second, third electrode assemblies) arranged vertically, with each assembly independently managed. The case is segmented into multiple compartments (first, second, third compartments) that separately accommodate each electrode assembly, allowing independent swelling management for each unit rather than treating the entire battery as a single stress concentration point.
Solution Approach 2:
The electrode assemblies are arranged in the vertical dimension (longitudinal direction) rather than horizontally, distributing the mass and stress along the length of the battery. This vertical arrangement with differentiated volumes (larger first assembly, smaller third assembly) creates a gradient distribution that reduces overall stress concentration while maintaining high capacity.
2Quantity of substance
If multiple electrode assemblies are arranged vertically in the case, then the battery capacity is increased, but the durability is reduced due to stress concentration
Solution Approach 1:
The battery system is segmented into multiple independent electrode assemblies with separate compartments, isolating stress concentrations to individual units rather than allowing them to propagate throughout the entire battery structure. This segmentation protects the overall durability even as capacity increases through multiple assemblies.
Solution Approach 2:
The electrode assemblies are designed with asymmetric volume distribution - the first electrode assembly has a larger volume than the second and third assemblies. This asymmetric arrangement optimizes the stress distribution pattern, placing larger mass away from critical connection points and reducing stress concentration effects that would compromise durability.
3Ease of manufacture
If the current collector volume is reduced to minimize material usage, then the manufacturing cost is reduced, but the current loss increases
Solution Approach 1:
The current collector is designed with non-uniform thickness - thicker at the first end connected to the larger first electrode assembly and thinner at the second end connected to smaller assemblies. This local quality variation optimizes electrical conductivity where needed (at the high-current first assembly connection) while reducing material usage in areas with lower current demands, thereby minimizing overall current loss without excessive material consumption.
Data Source
AI summary
A secondary battery includes a plurality of electrode assemblies, a current collector electrically connected to each of the electrode assemblies, a case accommodating the plurality of electrode assemblies and the current collector, a cap plate sealing the case, and an electrode terminal electrically connected to the current collector and penetrating the cap plate, wherein the plurality of electrode assemblies are arranged such that an axis of each electrode assembly is parallel to a bottom surface of the case and the plurality of electrode assemblies are disposed in a longitudinal direction.