Battery Cell Case Insulation Against Electrolyte Corrosion
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Solution Overview
Problem
The corrosion breakdown susceptibility of battery cell cases due to contact with electrolyte solution, leading to risks of combustion and explosion, is not adequately addressed in existing technologies.
Innovation Solution
A battery cell design featuring an insulating protective layer on the inner wall of the case, combined with an end cover and a lower plastic layer, to separate the case from the electrolyte solution and enhance insulation, thereby reducing the probability of corrosion and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the case directly contacts the electrolyte solution, then the battery structure is simple, but the case suffers from corrosion breakdown leading to combustion and explosion risks
Solution Approach 1:
An insulating protective layer is introduced as an intermediary between the case and the electrolyte solution. This layer prevents direct contact between the conductive case and the electrolyte, eliminating the corrosion pathway while maintaining structural simplicity. The protective layer acts as a mediator that resolves the contradiction by adding minimal complexity to achieve significant reliability improvement.
Solution Approach 2:
The insulating protective layer is implemented as a thin film coating on the inner wall of the case. This thin film approach provides effective corrosion protection without significantly increasing the overall battery structure complexity or volume. The flexible thin film conformally coats the case interior, ensuring comprehensive protection while maintaining manufacturing feasibility.
2Reliability
If an insulating protective layer is added on the inner wall of the case, then corrosion resistance is improved, but the device complexity increases
Solution Approach 1:
The insulating protective layer is applied in advance during the case manufacturing process, before the battery assembly is completed. This preliminary action ensures that the protective layer is already in place to prevent corrosion from the outset, rather than requiring additional protective measures during assembly or operation. The protective function is built-in from the beginning, reducing overall system complexity.
Solution Approach 2:
The protective layer changes the surface properties of the case by introducing an insulating material with different electrical and chemical parameters. This parameter change transforms the case surface from conductive and corrosion-prone to insulative and corrosion-resistant, achieving protection through material property modification rather than complex structural changes.
3Reliability
If the end cover is welded directly to the case, then the sealing is effective, but welding between the end cover and case becomes difficult due to the insulating protective layer
Solution Approach 1:
The protective layer coverage is segmented rather than continuous, with deliberate gaps or reduced coverage at the welding interface between the end cover and case. This segmentation allows the welding process to access the conductive case surface directly, maintaining welding ease, while the protective layer remains intact in other critical areas to ensure corrosion protection and sealing reliability.
Solution Approach 2:
The insulating protective layer is applied with varying coverage - fully present in areas requiring corrosion protection, but intentionally absent or reduced at the welding interface. This local quality variation ensures that welding operations can proceed easily on the exposed case surface while the protected areas maintain their insulating and protective properties, resolving the contradiction between sealing reliability and manufacturing ease.
Data Source
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AI summary
The present application provides a battery cell (20), a battery (100), and an electrical device, where the battery cell (20) includes a case (22) and an insulating protective layer (24), the insulating protective layer (24) being disposed on an inner wall of the case (22). In the battery cell (20) provided in the embodiments of the present application, the insulating protective layer (24) is disposed on the inner wall of the case of the battery cell (20), where the insulating protective layer (24) can separate the case (22) from the electrolyte solution inside the case (22), so as to reduce the probability of contact between the case (22) and the electrolyte solution, thereby lowering the probability of corrosion breakdown of the case (22).