Rectangular Battery Current Collecting Plate Thickness Design
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Solution Overview
Problem
Rectangular secondary batteries face challenges in suppressing heat generation in the current collecting plate, which is a limitation due to the constant thickness of the metallic plates used in their production.
Innovation Solution
A rectangular secondary battery design that incorporates a current collecting plate with a joint thicker than its fixed and welded portions, optimizing heat dissipation by varying the thickness and cross-sectional area to reduce electric resistance and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a constant thickness metallic plate is used for the current collecting plate, then the manufacturing process is simple, but heat generation cannot be suppressed effectively
Solution Approach 1:
The current collecting plate employs varying thickness across different regions: a first thickness in the joint region, a second thickness in the fixed portion, and a third thickness in the welded portion. This local quality variation allows the joint region to have higher heat dissipation capacity where current density is highest, while maintaining manufacturing feasibility through standardized plate production with localized thickness modification.
Solution Approach 2:
The invention changes the thickness parameter of the current collecting plate from a constant value to a variable value across different regions. Specifically, the joint has a first thickness, the fixed portion has a second thickness, and the welded portion has a third thickness, creating a gradient structure that optimizes heat dissipation while managing electrical resistance and mechanical strength.
2Temperature
If the thickness of the current collecting plate is increased to suppress heat generation, then heat dissipation improves, but material usage and weight increase
Solution Approach 1:
Instead of uniformly increasing the thickness of the entire current collecting plate, the invention applies local quality by making only the joint region thicker (first thickness) compared to the fixed portion (second thickness) and welded portion (third thickness). This localized thickening targets the specific area where heat generation is most problematic while minimizing overall material consumption and weight increase.
3Temperature
If the current collecting plate structure is optimized for heat dissipation, then thermal management improves, but manufacturing complexity increases
Solution Approach 1:
The invention implements local quality by creating a current collecting plate with three distinct thickness regions (joint, fixed portion, and welded portion), each optimized for its specific function. The joint has the greatest thickness for heat dissipation, the fixed portion has intermediate thickness for structural support, and the welded portion has the least thickness for flexibility and ease of connection, thereby optimizing thermal management without excessive structural complexity.
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 effectively suppresses heat generation in the current collecting plate, improving thermal management and reducing the maximum temperature difference when current flows, while also potentially decreasing material usage and weight.
Implementation Method 1
the joint has a portion thicker than the fixed portion or the welded portion... heat generation of the current collecting plate can be suppressed... reducing the maximum temperature difference when current flows
Implementation Method 2
a current collecting plate which electrically connects the external terminal and the wound group inside the battery can... optimizing heat dissipation by varying the thickness and cross-sectional area
Data Source
AI summary
A problem of the present invention is to provide a rectangular secondary battery in which heat generation of a current collecting plate is suppressed. A rectangular secondary battery of the present invention which solves the above-described problem includes: a flat wound group which is obtained by winding a positive electrode and has a positive electrode metal foil-exposed portion; a battery can which stores the wound group; a battery lid which seals the battery can; a positive electrode external terminal which is provided on the battery lid; and a positive electrode current collecting plate which electrically connects the external terminal and the wound group. The positive electrode current collecting plate includes a fixed portion fixed on the battery lid, a welded portion welded on the metal foil-exposed portion of the wound group, and a joint connecting the fixed portion and the welded portion. Further, in the current collecting plate, the joint has a width portion equal to or less than widths of the fixed portion and the welded portion and a thickness portion thicker than the fixed portion or the welded portion.