Resin-Layer Electrode Sheet for Battery Heat Dissipation Safety
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Solution Overview
Problem
Existing lithium ion secondary batteries face challenges in safety and heat management during abnormal conditions, such as overcharging or high temperatures, with issues related to electrical resistance and potential ignition.
Innovation Solution
The electrode sheet is designed with a current collector comprising a resin layer and multiple current collecting layers, along with metal sheets bonded to these layers, featuring extending parts and bonding marks to enhance heat dissipation and electrical connectivity, while maintaining safety by interrupting current flow in case of overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current collector with resin layer and multiple current collecting layers is used, then heat dissipation is enhanced and safety is improved, but device complexity increases
Solution Approach 1:
The current collector is divided into multiple current collecting layers (first, second, third current collecting layers) with a resin layer in between, creating a segmented structure that improves heat dissipation and safety while maintaining electrical conductivity through each layer
Solution Approach 2:
The current collector uses a composite structure combining metal layers (aluminum or aluminum alloy) with a resin layer, creating a multi-material system that leverages the electrical conductivity of metal and the thermal insulation/fire resistance of resin to achieve both conductivity and safety
2Reliability
If metal sheets with extending parts are bonded to current collecting layers, then electrical connectivity is maintained, but manufacturing complexity increases
Solution Approach 1:
The metal sheets are pre-formed with extending parts that protrude from the current collecting layers before assembly, allowing the terminal connection structure to be prepared in advance and simplifying the subsequent assembly process by reducing the need for additional forming operations
Solution Approach 2:
The metal sheets extend in the lateral direction beyond the current collecting layers, adding a dimensional element that enables terminal connections to be formed at the edges of the wound electrode, facilitating external electrical connections without compromising the internal layered structure
3Reliability
If bonding marks are formed along the longitudinal direction, then current flow interruption is achieved for safety, but manufacturing precision requirements increase
Solution Approach 1:
The bonding marks are formed during the normal bonding process between metal sheets and current collecting layers without requiring separate safety marking operations, allowing the safety feature to be integrated into the existing manufacturing process and reducing additional precision requirements
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 improves safety by preventing ignition and enhancing heat dissipation, maintaining electrical conductivity, and ensuring continuous power extraction even under abnormal conditions.
Implementation Method 1
a first metal sheet that is bonded to one end of the first current collecting layer in the lateral direction
Implementation Method 2
a first metal sheet that is bonded to one end of the first current collecting layer in the lateral direction and has a first bonding mark formed along the longitudinal direction by the bonding
Data Source
AI summary
In one exemplary embodiment, an electrode sheet is provided. The electrode sheet has a longitudinal direction and a lateral direction and constitutes an electrode of a secondary battery by being wound with the lateral direction as an axial direction. The electrode sheet includes a current collector that includes a resin layer, and a first current collecting layer and a second current collecting layer that are respectively provided on both surfaces of the resin layer; a first active material layer that is provided on a surface of the first current collecting layer on a side opposite to the resin layer; and a first metal sheet that is bonded to one end of the first current collecting layer in the lateral direction and has a first bonding mark formed along the longitudinal direction by the bonding, where the first metal sheet has a first extending part that extends from the first current collecting layer in the lateral direction.