Electrode Insulating Layer Design for Battery Short Circuit Prevention
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Solution Overview
Problem
Existing energy storage devices face issues with insulation properties due to shrinkage of separators and foreign substance intrusion, leading to potential short circuits between electrodes.
Innovation Solution
An energy storage device with an electrode assembly featuring a pair of overlapped electrodes, including a current collecting substrate, an active material layer, an intermediate layer with a carbonaceous material, and an insulating layer with an aqueous binder, which prevents carbonaceous material intrusion and enhances insulation by using nonaqueous and aqueous binders with different affinities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer is added to prevent short circuits, then insulation properties are improved, but device complexity increases
Solution Approach 1:
The electrode structure is segmented into multiple functional layers: current collecting substrate, active material layer, intermediate layer, and insulating layer. Each layer performs a specific function, with the insulating layer specifically designed to prevent short circuits while the intermediate layer provides additional protection against carbonaceous material intrusion.
Solution Approach 2:
An intermediate layer is introduced as a mediator between the current collecting substrate and the active material layer. This intermediate layer contains carbonaceous material and serves as a barrier to prevent foreign substance intrusion, while the insulating layer acts as another intermediary to enhance insulation properties and prevent electrode short circuits.
2Reliability
If multiple layers are added to enhance insulation, then insulation properties are improved, but manufacturing complexity increases
Solution Approach 1:
The electrode is divided into distinct segments or layers, each with a specific function. The insulating layer is applied on the current collecting substrate and in contact with at least the intermediate layer, creating a segmented structure that simplifies the manufacturing process by allowing each layer to be applied and treated independently.
Solution Approach 2:
The invention specifies particular parameters for each layer, such as the binder content (1-10 mass% of the insulating layer) and the use of specific binder types (aqueous or nonaqueous). These parameter specifications provide clear manufacturing guidelines, making the production process more controllable and easier to standardize despite the multi-layer structure.
3Reliability
If separator shrinkage is prevented by structural modifications, then reliability is improved, but device complexity increases
Solution Approach 1:
The insulating layer is applied in advance on the current collecting substrate before the electrode assembly is completed. This preliminary action ensures that the insulating properties are established before the electrode undergoes any shrinkage or assembly processes, preventing potential short circuits that could occur due to separator shrinkage.
Solution Approach 2:
The insulating layer acts as a protective cushion or barrier that is in place beforehand to prevent harmful effects. It provides a safety margin that compensates for any potential separator shrinkage or foreign substance intrusion, ensuring that the electrodes remain insulated even under stress or degradation conditions.
Data Source
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AI summary
There is provided an energy storage device having an insulating layer excellent in insulation properties. There is provided an energy storage device including an electrode assembly having a pair of electrodes overlapped with each other. At least one of the electrodes includes a current collecting substrate, an active material layer arranged on the current collecting substrate, an intermediate layer arranged between the current collecting substrate and the active material layer, and an insulating layer arranged on the current collecting substrate. The active material layer contains an active material and a first binder. The intermediate layer contains a carbonaceous material and a second binder. The insulating layer contains an insulating material and a third binder. The second binder is a nonaqueous binder. The third binder is an aqueous binder.