Branched Current Collector Sections for Battery Heat Management
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Solution Overview
Problem
Existing secondary batteries face challenges in achieving high energy density and efficient current collection while minimizing heat generation and maintaining fabrication ease, as the large volume of the flat-shaped electrode group within the metal case is limited by the size of the electrode leads and the complexity of connecting them.
Innovation Solution
The battery design includes a spiral projection of positive and negative electrode tabs, divided into two bundles and nipped by conductive members, allowing for even distribution of current collecting sections within the electrode group, reducing lead resistance, and enabling ultrasonic welding with improved space efficiency and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large volume of flat-shaped electrode group is stored in the metal case to enhance energy density, then energy density is improved, but the battery may be damaged by heat generated from large current flowing into leads
Solution Approach 1:
The lead structure is segmented into multiple current collecting sections (first and second current collecting sections) that are branched from the main lead. This segmentation distributes the large current across multiple smaller current paths, reducing the current density and heat generation at any single point while maintaining effective current collection from the large-volume electrode group
2Productivity
If individual metal foils are laminated/bundled and leads are welded to enhance current collecting efficiency, then current collecting efficiency is improved, but the complexity of connecting leads increases
Solution Approach 1:
Multiple current collecting sections are merged into a single integrated lead structure. The first and second current collecting sections are both connected to the main lead, creating a unified current collection system that simplifies the connection process while maintaining high current collecting efficiency from the bundled metal foils
3Quantity of substance
If the volume of the flat-shaped electrode group is increased to enhance energy density, then energy density is improved, but the space available for electrode group is limited by the size of leads and connecting sections
Solution Approach 1:
The lead structure utilizes the thickness direction of the electrode group by positioning current collecting sections at different locations along the thickness. This three-dimensional arrangement of current collection points maximizes space utilization, allowing larger electrode group volume while maintaining effective electrical connection
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
This design enhances energy density by maximizing the volume of the electrode group within the case, ensures effective current collection, and simplifies the fabrication process while reducing heat concentration and increasing the reliability of connections.
Implementation Method 1
a conductive positive electrode nipping member and a conductive negative electrode nipping member, which electrically connect a positive electrode lead and a negative electrode lead to a positive electrode tab and a negative electrode tab, respectively
Implementation Method 2
enabling ultrasonic welding with improved space efficiency and heat dissipation
Data Source
AI summary
According to one embodiment, a battery includes an electrode group, a tab, a conductive nipping member, a case, a lid and a lead. The conductive nipping member includes first and second nipping sections. The first and second nipping sections divide the tab into two bundles in which portions of the tab are laminated onto each other in a thickness direction of the electrode group. The lead includes a connecting section connected electrically to a terminal, and current collecting sections which are two sections branched from the connecting section and sandwiching the nipping member.