Grooved Negative Electrode Interface for Thicker Li-Ion Cells
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Solution Overview
Problem
Lithium-ion batteries experience deformation and cycling degradation due to internal stress accumulation during charge-discharge cycles, leading to safety concerns and reduced cycling stability, exacerbated by inadequate heat dissipation.
Innovation Solution
The design of a secondary battery with grooves on the negative electrode plate surface and a binding layer on the separator, adjusting groove width, spacing, and thickness to enhance the binding interface, using polymers and heat-resistant materials to increase the contact area and binding force between the electrode and separator, thereby mitigating deformation and improving safety and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electrode assembly thickness is increased to achieve higher energy density, then the specific energy is improved, but the internal stress accumulation and deformation are exacerbated
Solution Approach 1:
The negative electrode plate surface is segmented into multiple grooves that divide the electrode structure into smaller units. This segmentation allows stress to be distributed across multiple smaller regions rather than accumulating uniformly, reducing overall deformation while maintaining the electrode's energy storage capacity
Solution Approach 2:
Grooves are strategically positioned at specific locations on the negative electrode plate where stress concentration is most likely to occur. The local structural modification at these critical positions provides enhanced stress relief without compromising the overall energy density of the battery
2Stability of the object's composition
If the binding interface between the negative electrode plate and separator is strengthened to improve cycling stability, then the deformation is reduced, but the contact area and binding force are insufficient in conventional flat designs
Solution Approach 1:
The binding interface is transformed from a two-dimensional flat surface to a three-dimensional structured surface with grooves. This dimensional change increases the effective contact area between the electrode and separator by creating multiple contact zones within the groove structures, thereby enhancing binding force without increasing the overall footprint
3Object-affected harmful factors
If heat dissipation is improved to enhance safety, then the thermal runaway risk is reduced, but the heat accumulation during cycling remains a challenge
Solution Approach 1:
The groove structures segment the electrode assembly into multiple thermal zones that can dissipate heat more effectively. By dividing the continuous electrode structure into smaller segments separated by grooves, heat accumulation is prevented in any single location, and thermal runaway propagation is inhibited
Data Source
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AI summary
This application provides a secondary battery and an electronic apparatus. The secondary battery includes an electrode assembly. The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. The separator is disposed between the positive electrode plate and the negative electrode plate. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer. A surface of the negative electrode active material layer facing towards the positive electrode plate has grooves, a width of the groove is W mm, and a spacing of the grooves is S mm. A thickness of the electrode assembly is T1 mm, satisfying: W ≥ S × T1/1000. In this application, with the width of the groove, the spacing of the grooves, and the thickness of the electrode assembly adjusted to satisfy the ranges of this application, a contact area between a surface of the negative electrode plate and the separator can be adjusted according to lithium-ion batteries of different thicknesses, thereby increasing a binding force between the negative electrode plate and the separator. This improves stability of the negative electrode plate, mitigates deformation issues of the lithium-ion battery, and enhances cycling stability and safety of the lithium-ion battery.