Laminated Electrode Current Collector Bundles for Structural Stability
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Solution Overview
Problem
Secondary batteries with laminated electrode bodies housed in square hard cases face challenges in structural stability and current-collecting efficiency, particularly during high-rate charge and discharge cycles, due to low holding forces between electrode sheets and separators, and insufficient current-collecting structures.
Innovation Solution
A secondary battery design featuring a laminated electrode body with rectangular sheet-shaped positive and negative electrodes, a separator, and a current-collecting structure where exposed current collector portions are bundled and joined to form multiple current collector bundles, which are individually connected to the electrode terminals, providing increased holding force and stability through pressure and adhesion, allowing for high-rate charge and discharge capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a laminated electrode body is housed in a square hard case, then physical strength and security are improved, but structural stability of the electrode body itself deteriorates
Solution Approach 1:
The current collector is divided into multiple bundles (first current collector bundle and second current collector bundle) that extend in the lamination direction. These segmented bundles provide distributed support points that stabilize the electrode body structure while maintaining the overall physical strength provided by the hard case.
Solution Approach 2:
The current collector bundles extend in the lamination direction (thickness dimension) rather than only in the plane direction. This dimensional change allows the current collector to provide structural support throughout the thickness of the electrode body, preventing deformation and maintaining stability within the hard case.
2Stability of the object's composition
If holding force between electrode sheets and separator is increased, then positional displacement is prevented, but device complexity increases
Solution Approach 1:
The current collector serves dual functions: it collects current electrically and provides structural support mechanically. By making the current collector extend in the lamination direction and form bundles, it simultaneously prevents positional displacement of electrode sheets and separators while maintaining electrical functionality, avoiding the need for separate holding structures.
Solution Approach 2:
The current collector structure itself provides the holding force needed to prevent displacement. The bundled configuration and extension in the lamination direction enable the current collector to self-support the electrode body structure without requiring additional external holding mechanisms, thereby preventing positional displacement through its own structural design.
3Power
If current-collecting structure is enhanced for high-rate charge and discharge, then power capability is improved, but manufacturing complexity increases
Solution Approach 1:
The current collector is segmented into multiple bundles that extend in the lamination direction. This segmentation increases the effective current collection area and improves electron transport efficiency, enabling high-rate charge and discharge. The segmented bundle structure is achieved through standard lamination processes, maintaining manufacturing feasibility.
Solution Approach 2:
The current collector bundles extend in the lamination direction (thickness dimension), creating a three-dimensional current collection network. This dimensional change increases the number of current collection pathways and reduces resistance, improving power capability for high-rate charge and discharge while being formed through conventional lamination techniques.
Data Source
AI summary
A secondary battery is provided, which includes a laminated electrode body and which has a current-collecting structure with favorable structural stability even when mounted to a vehicle and with superior high-rate charge-discharge characteristics. In a laminated electrode body included in a secondary battery provided by the present invention, a laminated positive electrode current collector-exposed portion and a laminated negative electrode current collector-exposed portion respectively constitute a plurality of current collector bundles which are bundled while being divided into two or more in a direction of lamination, each of the plurality of current collector bundles is individually and separately joined to the current collector portion on the same electrode side, and any of separators between positive and negative electrodes is enveloped in any of the plurality of current collector bundles on the side of the positive electrode current collector-exposed portion and/or any of the plurality of current collector bundles on the side of the negative electrode current collector-exposed portion.