Non-aqueous Electrolyte Battery Intermediate Layer Contact
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary batteries face safety issues due to short-circuits between the positive and negative electrodes, leading to abnormal heat generation, and existing solutions require complex configurations to achieve low-resistance contact.
Innovation Solution
A non-aqueous electrolyte secondary battery design where the positive electrode current collector is exposed over a length dimension of at least one turn in the intermediate layer portion, and the negative electrode has a lower resistance active material layer with a separation portion to prevent ion diffusion, allowing for a simple configuration that maintains low-resistance contact even during short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a positive electrode current-collector-exposed portion and a negative electrode current-collector-exposed portion are allowed to face each other on both ends of each electrode, then contact of metal with low resistance can be obtained more reliably, but the configuration becomes more complex
Solution Approach 1:
The invention extracts the essential function of low-resistance contact by providing only the positive electrode current-collector-exposed portion in the intermediate layer, eliminating the need for a negative electrode current-collector-exposed portion. This selective extraction maintains the low-resistance contact function while simplifying the overall configuration.
Solution Approach 2:
The invention applies local quality by concentrating the current collector exposure function specifically in the positive electrode at the intermediate layer portion, rather than requiring symmetric exposure of both electrodes. This localized approach achieves the necessary electrical contact function with reduced structural complexity.
2Reliability
If current collector opposing surfaces are provided in intermediate parts of winding to prevent short-circuits, then safety is improved, but the device complexity increases
Solution Approach 1:
The invention performs preliminary action by pre-positioning the positive electrode current-collector-exposed portion in the intermediate layer before any short-circuit event occurs. This pre-configured structure ensures that low-resistance contact is already established, so that if a short-circuit occurs, the safety function is immediately activated without requiring additional structural elements.
Solution Approach 2:
The positive electrode current-collector-exposed portion in the intermediate layer acts as an intermediary structure that mediates between the positive and negative electrodes. It provides a controlled path for electrical contact that prevents uncontrolled short-circuits while maintaining safety, eliminating the need for complex opposing surface structures.
3Quantity of substance
If the negative electrode active material layer is provided on both surfaces of the current collector, then the battery capacity is increased, but ion diffusion leading to irreversible capacity occurs
Solution Approach 1:
The invention applies local quality by providing the negative electrode active material layer on both surfaces of the current collector except in the specific region facing the positive electrode current-collector-exposed portion in the intermediate layer. This localized exclusion prevents ion diffusion in the critical area while maintaining battery capacity in other regions.
Data Source
AI summary
A non-aqueous electrolyte secondary battery includes battery element formed by laminating and winding positive electrode and negative electrode via separator. Positive electrode includes a positive electrode current-collector-exposed portion, in which the positive electrode current collector is exposed over a length dimension of not less than one turn of the winding of battery element in the outermost circumference and an intermediate layer portion of the winding. The negative electrode in a part facing the positive electrode current collector exposed in the intermediate layer portion includes the negative electrode active material layer laminated on the negative electrode current collector. Negative electrode can be provided with a slit at an exposed side with respect to both exposed ends of the positive electrode current-collector-exposed portion.