Secondary Battery Electrode Plate with Gradient Conductive Layer
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Solution Overview
Problem
The existing electrode plates in secondary batteries face issues with safety performance and overcurrent capability due to deformation and cracking during the rolling process, which affects the energy density and the ability to transmit electric current effectively.
Innovation Solution
The electrode plate design includes a current collector with an insulating layer and a first conducting layer, where the protruding portion is not coated with the active material layer, and a second conducting layer with reduced stiffness made from a non-metallic material, which is connected to the first conducting layer and active material layer, and a protecting layer to enhance the structural integrity and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode plate is subjected to rolling force to thin the active material layer, then energy density is improved, but the insulating layer and conducting layer deform differently causing the protruding portion to bulge and crack, reducing overcurrent capability
Solution Approach 1:
The patent changes the material parameters of the conducting layer by using a multi-layer structure with different elastic moduli. The first conducting layer has a higher elastic modulus than the insulating layer, while the second conducting layer has a lower elastic modulus, creating a gradient structure that accommodates differential deformation during rolling and prevents cracking
Solution Approach 2:
The patent employs a composite multi-layer conducting layer structure consisting of an insulating layer, a first conducting layer with higher elastic modulus, and a second conducting layer with lower elastic modulus. This composite structure combines the benefits of both high and low stiffness materials to prevent cracking while maintaining conductivity
2Reliability
If a multi-layer current collector structure is chosen to improve safety performance, then safety is enhanced, but the differential deformation between layers causes cracking in the protruding portion
Solution Approach 1:
The patent optimizes the elastic modulus parameters of each layer to create a gradient structure. The first conducting layer has higher elastic modulus for structural support, while the second conducting layer has lower elastic modulus to accommodate deformation, preventing crack propagation and maintaining strength
Solution Approach 2:
The patent incorporates a second conducting layer with lower elastic modulus that acts as a cushioning layer beforehand, absorbing and distributing the stress concentration that would otherwise lead to cracking in the protruding portion during rolling and operation
Data Source
AI summary
The present disclosure provides a secondary battery and an electrode plate thereof. The electrode plate comprises a current collector, an active material layer and a second conducting layer. The current collector comprises an insulating layer and a first conducting layer disposed on at least one surface of the insulating layer; and the active material layer is disposed on a main portion of the first conducting layer. The first conducting layer further includes a protruding portion not coated with the active material layer. The second conducting layer comprises a first portion disposed on a surface of the protruding portion of the first conducting layer opposite to the insulating layer. The secondary battery comprises an electrode assembly, the electrode assembly comprises the electrode plate.