Battery Electrode Insulating Window for Mixture Layer Alignment
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Solution Overview
Problem
The formation of an insulating layer on electrodes in secondary batteries makes it difficult to confirm the position of the mixture layer, leading to displacement issues during lamination and winding, and existing coating methods obscure the mixture layer's width and position, hindering accurate adjustment and production.
Innovation Solution
A secondary battery design that incorporates a transparent insulating layer with a window portion to visually recognize the end of the mixture layer, allowing for accurate adjustment of electrode positions during winding, and a method for simultaneous coating and drying of the mixture and insulating layers on a current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer is formed on the electrode to prevent heat spread and internal short-circuit, then safety is improved, but the mixture layer position becomes unconfirmable leading to lamination displacement
Solution Approach 1:
The insulating layer incorporates a transparent portion that allows visual recognition of the mixture layer's end position through the layer itself. This transparency creates an optical property change that enables position confirmation while maintaining the insulating function, thus resolving the contradiction between safety and manufacturing precision
Solution Approach 2:
The transparent portion acts as an intermediary element within the insulating layer that mediates between the insulating function and the position confirmation requirement. It allows light transmission to reveal the mixture layer position while the insulating layer continues to provide thermal and electrical insulation
2Reliability
If the insulating layer is formed to avoid increase in internal short-circuit region, then reliability is improved, but inspection of mixture layer width and position becomes impossible
Solution Approach 1:
The transparent portion creates an optical property change in the insulating layer that enables visual inspection of the mixture layer's width and position. The transparency allows light to pass through and reveal the underlying mixture layer boundaries, making detection and measurement possible while maintaining insulating properties
Solution Approach 2:
The transparent portion introduces an optical dimension to the insulating layer, allowing inspection through the layer rather than requiring direct line-of-sight access. This dimensional change in light transmission enables measurement and detection capabilities while preserving the insulating function
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
Enables accurate confirmation and adjustment of mixture layer positions, ensuring precise lamination and reliable production of lithium ion secondary batteries, even when the insulating layer is formed, and facilitates a rational manufacturing process.
Implementation Method 1
a transparent insulating layer with a window portion to visually recognize the end of the mixture layer
Implementation Method 2
a method for simultaneous coating and drying of the mixture and insulating layers on a current collector
Implementation Method 3
simultaneous coating and drying of the mixture and insulating layers
Data Source
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AI summary
An object of the present invention is to obtain a secondary battery that allows grasping a position of a mixture layer on an electrode and facilitates adjustment of positions of a positive electrode and a negative electrode. A secondary battery (100) of the present invention includes a negative electrode (32) that includes a strip-shaped copper foil (45) having both surfaces, negative electrode mixture layers (32a) on both the surfaces, a negative electrode foil exposed portion (32b), and insulating layers (31). The negative electrode foil exposed portion (32b) where the copper foil (45) is exposed is formed in an end portion on one side in a width direction of the copper foil (45). The insulating layers (31) are disposed on the negative electrode mixture layers (32a) and on the negative electrode foil exposed portion (32b). The insulating layer (31) includes a window portion (31a) at a position corresponding to a boundary part between the negative electrode mixture layer (32a) and the negative electrode foil exposed portion (32b). An end portion of the negative electrode mixture layer (32a) is visually recognizable from the window portion (31a).