Lithium Battery Electrode Layout for Short-Circuit Insulation
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Solution Overview
Problem
Rechargeable lithium batteries with high energy density face challenges in securing safety and reliability while minimizing energy density reduction, particularly during driving applications, due to difficulties in preventing short circuits and maintaining insulation.
Innovation Solution
The electrode design includes a current collector with a safety functional layer and an insulating layer, where the safety functional layer is longer than the active material layer, and the insulating layer is positioned on a separate region, ensuring a specific separation distance to divert current flow and reduce Joule heat during short circuits, thus enhancing safety and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating layer is extended to cover the entire current collector surface, then insulation reliability is improved, but energy density decreases due to increased material usage and reduced active material area
Solution Approach 1:
The current collector surface is divided into a first region (where active material is located) and a second region (spaced apart from the first region). The insulating layer is selectively disposed only on the second region, creating spatial segmentation that provides insulation where needed while preserving active material area and energy density where it matters.
Solution Approach 2:
The insulating layer is applied locally to specific regions rather than uniformly across the entire current collector. By concentrating insulation only on the second region where it is most needed for safety, the design achieves high insulation reliability without the penalty of widespread material usage that would reduce energy density.
2Reliability
If the safety functional layer length is increased to provide better short circuit protection, then safety is improved, but energy density decreases due to reduced active material area
Solution Approach 1:
The safety functional layer is segmented in length, extending beyond the active material layer only in specific regions. This selective extension provides enhanced short circuit protection where it is most needed while preserving active material area in other regions, thereby maintaining energy density.
Solution Approach 2:
The safety functional layer is applied with varying lengths across different regions of the current collector. By making the safety layer longer only where short circuit risks are highest and shorter elsewhere, the design achieves maximum safety protection with minimal impact on energy density.
3Reliability
If the separation distance between the active material layer and insulating layer is increased, then short circuit prevention is improved, but device complexity increases
Solution Approach 1:
The current collector is segmented into distinct first and second regions with specific spatial relationships. The insulating layer is disposed on the second region at optimized separation distances from the active material layer, creating a structured layout that prevents short circuits through deliberate spatial arrangement rather than complex additional components.
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 configuration effectively secures safety and reliability by minimizing energy density loss during operation, reducing exothermic reactions, and preventing lithium precipitation, while maintaining battery performance and capacity.
Implementation Method 1
a length of the safety functional layer is longer than that of the active material layer; the insulating layer is disposed on the second region... reducing Joule heat during short circuits
Data Source
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AI summary
An electrode for a rechargeable lithium battery includes a current collector, a safety functional layer, an active material layer, and an insulating layer, wherein in a longitudinal direction of the current collector, one surface of the current collector is partitioned into a first region and a second region spaced apart from the first region, the safety functional layer and the active material layer are sequentially stacked in the first region, the insulating layer is disposed on the second region, and the electrode satisfies Equation 1: a>b In Equation 1, a and b are as defined in the specification.