High Resistance Current Collector for Battery Short Circuit Safety
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Solution Overview
Problem
Lithium-ion batteries face safety hazards such as fires and explosions due to internal short circuits caused by abnormal conditions like collision or puncture, and existing solutions fail to effectively prevent these incidents while ensuring normal battery operation.
Innovation Solution
A current collector with a conductive layer having a room temperature film resistance of 0.01Ω/sq to 0.15Ω/sq, combined with an insulation layer, which reduces short circuit current and heat generation, limiting damage to a 'point break' and maintaining normal battery operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alloy having low melting point is added into the material of metal current collector, then the safety of the battery is improved by melting and breaking the circuit, but the battery cannot continue to operate and temperature rises sharply
Solution Approach 1:
The invention changes the resistance parameter of the current collector from conventional low resistance to high resistance (≥100 mΩ·cm). This parameter change allows the current collector to limit short circuit current through resistive heating without requiring phase change or circuit breakage, enabling both safety improvement and continuous operation.
Solution Approach 2:
The invention converts the harmful effect of short circuit current into a beneficial safety mechanism by utilizing Joule heating from high resistance to generate heat that triggers the separator's shutdown function, thereby converting the dangerous short circuit condition into a controlled safety response.
2Reliability
If multilayered current collector with resin layer is adopted, then the safety is improved by melting resin layer to cut off current, but the battery cannot continue to operate and temperature rises sharply
Solution Approach 1:
The invention changes the resistance parameter of the current collector from conventional low resistance to high resistance (≥100 mΩ·cm). This parameter change allows the current collector to limit short circuit current through resistive heating without requiring phase change or circuit breakage, enabling both safety improvement and continuous operation.
Solution Approach 2:
The invention replaces the mechanical phase-change-based safety mechanism (melting resin or alloy) with an electrical resistance-based mechanism. The high resistance current collector uses Joule heating to trigger the separator's shutdown function, eliminating the need for multilayered structures with melting components.
3Productivity
If conventional current collector with low resistance is used, then the electrochemical performance is maintained, but the short circuit current is high causing temperature rise and safety hazards
Solution Approach 1:
The invention changes the resistance parameter of the current collector from conventional low resistance to high resistance (≥100 mΩ·cm). This parameter change allows the current collector to limit short circuit current through resistive heating without requiring phase change or circuit breakage, enabling both safety improvement and continuous operation.
Solution Approach 2:
The invention applies different functional properties to different aspects of the current collector: high resistance for safety (limiting short circuit current) while maintaining appropriate conductivity for normal electrochemical operation. The high resistance specifically activates during abnormal conditions to limit current, while normal operation proceeds with adequate conductivity.
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
The solution significantly enhances safety performance by reducing short circuit current and heat, preventing accidents like fires and explosions, while maintaining the battery's normal operation and electrochemical performance.
Implementation Method 1
The at least one conductive layer has a room temperature film resistance Rs satisfying 0.01 Ω/sq ≤ Rs ≤ 0.15 Ω/sq, thereby significantly reducing a short circuit current in case of a short circuit
Data Source
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AI summary
The present application relates to a current collector, an electrode plate, a battery and usages thereof. The current collector includes at least one conductive layer configured to support an electrode active material layer, and an insulation layer configured to support the at least one conductive layer. The conductive layer has a room temperature film resistance RS satisfying 0.01 Ω /sq ≤ RS ≤ 0.15 Ω /sq. The current collector can significantly increase resistance in short-circuit and reduce current in the short-circuit, and reduce heat generated during the short-circuit and improving safety performance. The heat can be totally absorbed by the battery. Therefore, the resulted temperature rise of the battery is small, the damage to the battery caused by the short circuit can be limited to a "point", and only a "point break" is formed, without influencing normal operation of the battery in a short time.