Jelly-Roll Electrode Insulation for Nail Penetration Safety
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Solution Overview
Problem
Current electrochemical devices, such as lithium-ion batteries, face safety issues due to external force punctures leading to potential explosions, particularly in high-capacity batteries, where conventional methods like copper-aluminum short circuits fail to prevent thermal runaway.
Innovation Solution
An electrochemical device design featuring a jelly roll structure with a first electrode and a second electrode separated by a separator, where the first electrode includes a current collector with a coated region and an uncoated region having alternating bent and straight portions, with the bent portions coated with an insulating layer to reduce heat accumulation during nail penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the first current collector is fully coated with first active material to maximize energy density, then the energy density is improved, but the safety performance deteriorates due to increased susceptibility to short-circuiting during external force puncture
Solution Approach 1:
The patent applies local quality by creating different regions on the first current collector with different properties: the coated region has first active material for energy storage, while the uncoated region provides safety protection. This spatial differentiation allows the same component to serve dual functions of energy density and safety protection simultaneously.
2Reliability
If the uncoated region is completely covered with insulating layer to prevent short-circuiting, then the safety performance is improved, but the manufacturing complexity increases due to additional coating processes and quality control requirements
Solution Approach 1:
The patent applies partial action by coating only the uncoated region with insulating material rather than the entire current collector. This selective coating approach provides sufficient safety protection at the critical uncoated regions while avoiding the complexity of full-surface coating processes and associated quality control requirements.
3Reliability
If alternating bent portions and straight portions are created in the uncoated region with insulating layer on bent portions, then the safety performance is improved by reducing heat accumulation during nail penetration, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies curvature by designing alternating bent portions and straight portions in the uncoated region. The bent portions, when coated with insulating material, create a structured pattern that effectively reduces heat accumulation during nail penetration tests. This geometric design provides safety enhancement while maintaining compatibility with standard manufacturing capabilities.
Data Source
AI summary
An electrochemical device, including a cell and a shell enclosing the cell; the cell includes a jelly roll including a first electrode and a second electrode spaced from each other, a separator is disposed between the first electrode and the second electrode, the first electrode and the second electrode are wound to form the cell; the first electrode includes a first current collector, the first current collector includes a first surface and a second surface disposed oppositely; the first surface faces the shell, and includes a coated region coated with a first active material and an uncoated region; the uncoated region includes a first uncoated region disposed at an end of the jelly roll, and the first uncoated region includes alternating bent portions and straight portions; and the bent portions are provided with an insulating layer.