Pouch Secondary Battery Electrode Layout for Shorter Current Paths
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Solution Overview
Problem
Existing secondary batteries face challenges in reducing electrical resistance and enhancing current path efficiency, particularly due to the long distance current travels from electrode tabs located at the ends of the electrode assembly, which affects output capacity.
Innovation Solution
The design incorporates uncoated portions of electrode plates on both sides of the electrode assembly, with terminals connected to these portions on opposite sides, and a zigzag separator configuration to minimize current travel distance, along with parallel extension members for the terminals to reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrode tabs are located at the ends of the electrode assembly, then the battery structure is simple and easy to manufacture, but the current travel distance is long causing high electrical resistance
Solution Approach 1:
The electrode assembly is segmented into multiple stacks arranged in series, with uncoated portions positioned at both ends of each stack. This segmentation allows current to travel shorter distances within each stack while maintaining the overall voltage through series connection, thereby reducing electrical resistance without complicating the manufacturing process.
Solution Approach 2:
The uncoated portions are positioned not only at the longitudinal ends but also distributed across multiple width directions of the electrode assembly. This multi-dimensional arrangement creates multiple parallel current paths, effectively reducing the electrical resistance by providing alternative routes for current flow.
2Reliability
If uncoated portions are integrated on both sides of the electrode assembly, then the current path is shortened and resistance is reduced, but the device complexity increases
Solution Approach 1:
The uncoated portions serve multiple functions: they act as current collectors, provide structural support for the electrode stacks, and facilitate thermal management. By integrating these functions into a single structural element, the design reduces overall device complexity while achieving the goal of shortened current paths and reduced resistance.
Solution Approach 2:
The positive and negative electrode uncoated portions are merged into an integrated structure at both ends of the electrode assembly. This merging creates a unified current collection system that simplifies the overall device architecture while maintaining short current paths and low resistance through the combined structure.
3Productivity
If the separator is bent in a zigzag direction, then the current path efficiency is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The separator is designed with a controlled zigzag curvature pattern that guides ion flow efficiently between electrode stacks. This predetermined curvature is incorporated during the stacking process using specialized equipment that can achieve the required precision, thereby balancing improved current path efficiency with feasible manufacturing precision requirements.
Data Source
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AI summary
A secondary battery (1) includes: an electrode assembly (10) comprising a first electrode plate (20), a second electrode plate (30), and a separator (40), the electrode assembly (10) being formed such that a first uncoated portion (22) connected to the first electrode plate (20) is located on one side of the electrode assembly (10) in a width direction and a second uncoated portion (32) connected to the second electrode plate (30) is on an opposite side of the electrode assembly (10) in the width direction; a pouch unit (50) accommodating the electrode assembly (10); a first electrode terminal (60) electrically connected to the first uncoated portion (22) and located on one side of the pouch unit (50) in the width direction; and a second electrode terminal (70) electrically connected to the second uncoated portion (32) and located on an opposite side of the pouch unit (50) in the width direction.