Prismatic Battery Insulating Buffer for Drop Impact
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Solution Overview
Problem
Prismatic secondary batteries are prone to internal short circuits when dropped, particularly when the mass of the wound electrode body and non-aqueous electrolyte solution exceeds 200 g, due to the proximity of the current collector bases to the electrode body, leading to potential contact and shorting of positive and negative terminals.
Innovation Solution
Incorporating an insulating buffer, such as an insulating tape, between the wound electrode body and the current collector bases, which differs from the separators, to create a buffer zone and prevent direct contact between the electrode body and the current collectors, thereby reducing the risk of short circuits during drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the current collector bases are disposed close to the wound electrode body to reduce battery size and improve energy density, then the battery capacity and energy density are improved, but the risk of internal short circuit increases when the battery is dropped
Solution Approach 1:
An insulating buffer is introduced as an intermediary component between the current collector base and the wound electrode body. This buffer serves as a mediator that maintains electrical isolation while allowing the current collector base to be positioned close to the electrode body, thus preserving high energy density while preventing short circuits during drops.
Solution Approach 2:
The insulating buffer is pre-installed between the current collector base and the wound electrode body before assembly. This beforehand cushioning ensures that when the battery is dropped and the current collector base contacts the electrode body, the insulating buffer is already in place to absorb the impact and maintain electrical isolation, preventing short circuits.
2Reliability
If an insulating buffer is added between the current collector base and the wound electrode body to prevent short circuits, then the short circuit resistance is improved, but the device complexity increases
Solution Approach 1:
The insulating buffer is implemented as a thin film or sheet material that can be easily placed between the current collector base and the wound electrode body. This thin film approach provides effective electrical isolation and impact absorption without adding significant structural complexity or volume to the battery design.
Solution Approach 2:
The insulating buffer changes the physical parameters of the interface between the current collector base and the wound electrode body by introducing a material with different electrical conductivity and mechanical properties. This parameter change ensures electrical isolation and impact absorption while maintaining a simple overall structure.
Data Source
AI summary
A prismatic secondary battery includes a first current collector and a second current collector. The first current collector includes a first base disposed along a sealing plate. The second current collector includes a second base disposed along the sealing plate. A distance between an end portion of a wound electrode body facing the sealing plate and a surface of the first base facing the wound electrode body at an end portion of the first base on a central side in the longitudinal direction of the sealing plate is shorter than a distance between the end portion of the wound electrode body facing the sealing plate and a surface of the second base facing the wound electrode body at an end portion of the second base on the central side. An insulating buffer is disposed between the wound electrode body and the above surface of the first base.