Lithium Battery Electrode Stack Insulation for Impact Short-Circuit Safety
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Solution Overview
Problem
Lithium secondary batteries face safety issues due to potential short circuits and heat generation during external impacts, which can lead to explosions.
Innovation Solution
An electrode stack design with alternating positive and negative electrodes and a separator, featuring a protective layer between the positive electrode collector and active material layer, and an insulation layer on the outermost positive electrode to prevent direct contact and reduce heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode stack uses a conventional structure without additional protective and insulation layers, then the device complexity is low, but safety deteriorates due to potential short circuits and heat generation during external impacts
Solution Approach 1:
The patent introduces a protective layer between the positive electrode collector and positive electrode active material layer, and an insulation layer on the outermost positive electrode. These intermediary layers prevent direct contact between electrodes during external impacts and manage heat generation, thereby resolving the safety issue without fundamentally changing the core electrode structure
Solution Approach 2:
The protective and insulation layers are pre-formed on the electrode structure before the battery is assembled and before any external impact occurs. This preliminary protective measure ensures that when external impacts happen, the short circuit prevention and heat management functions are already in place, improving safety without requiring complex real-time response systems
2Reliability
If the insulation layer thickness is increased to improve safety, then short circuit prevention improves, but heat dissipation deteriorates due to increased thermal resistance
Solution Approach 1:
The patent optimizes the insulation layer thickness to a specific range (1 μm to 8 μm) to achieve the best balance between short circuit prevention and heat dissipation. This parameter optimization ensures sufficient electrical insulation while maintaining adequate thermal management, resolving the contradiction between safety and heat dissipation
3Reliability
If the protective layer is added between the positive electrode collector and active material layer, then safety during external impact improves, but manufacturing complexity increases
Solution Approach 1:
The protective layer is applied locally only to the positive electrode collector where it is most needed for preventing short circuits during external impacts, rather than coating all electrode components uniformly. This localized approach provides targeted safety enhancement while minimizing the overall manufacturing complexity and material usage
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 design effectively prevents short circuits and reduces the risk of explosions by increasing resistance and managing heat release during external impacts, enhancing safety.
Implementation Method 1
increasing resistance and preventing a short circuit between electrodes
Implementation Method 2
heat generated from the positive electrode during an external impact may be effectively released
Data Source
AI summary
The present disclosure relates to an electrode stack for a lithium secondary battery, in which one or more positive electrodes and one or more negative electrodes are alternatingly stacked with a separator therebetween and insulation layers are formed on the outermost positive electrodes of the electrode stack. The insulation layers have an average thickness of 1 μm to 8 μm. The positive electrodes include a positive electrode collector; a positive electrode active material layer; and a protective layer including an inorganic compound. The protective layer is disposed between the positive electrode collector and the positive electrode active material layer. Additionally, an electrode assembly and a lithium secondary battery which include the electrode stack are also disclosed.