Secondary Battery External Terminal Protection via Segmented Cover
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Solution Overview
Problem
Conventional secondary battery manufacturing processes face challenges with complex molding operations, material inefficiencies, and structural stability due to the need for precise application of molding resin between the bare cell and protection circuit board, leading to increased costs and reduced productivity.
Innovation Solution
A secondary battery design featuring a board exterior cover with a hard insulating cover body and bonding layer to protect the external terminal, paired with cutout portions for exterior cases, simplifies the molding process and enhances structural stability by reducing the volume of molding resin and exterior case material, allowing for thinner, more robust construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If molding resin is applied to the space between the bare cell and protection circuit board, then the external terminal is protected from external impacts, but the amount of molding resin required increases and the molding operation becomes complex
Solution Approach 1:
The protection structure is segmented into two parts: a board exterior cover that covers the protection circuit board and external terminal, and a reduced amount of molding resin that fills only the necessary space between the bare cell and protection circuit board. This segmentation simplifies the molding operation while maintaining protection of the external terminal.
Solution Approach 2:
The board exterior cover is installed on the protection circuit board before the molding operation. This preliminary action provides pre-protection for the external terminal, allowing the subsequent molding operation to use less resin and be simpler, as it only needs to fill the remaining space rather than covering the entire surface.
2Reliability
If the space between bare cell and protection circuit board is extended to one surface of external terminal, then the external terminal can be covered, but the insertion of molding resin becomes difficult and productivity deteriorates
Solution Approach 1:
The protection system is divided into the board exterior cover component and the molding resin component. The board exterior cover is inserted first to cover the protection circuit board and external terminal, creating a defined space that simplifies the subsequent molding resin insertion. This segmentation transforms a complex single-step insertion into two simpler sequential steps.
3Reliability
If molding resin is applied to cover the protection circuit board surface, then external terminal protection is improved, but the overall thickness of secondary battery increases
Solution Approach 1:
The board exterior cover is installed as a preliminary protective layer on the protection circuit board before molding. This pre-existing cover provides the necessary protection for the external terminal, allowing the molding resin to be applied in a thinner layer that only needs to fill the remaining space, thereby reducing the overall battery thickness while maintaining protection.
4Stability of the object's composition
If a separate exterior case is used to cover the protection circuit board, then structural stability is improved, but the amount of material required increases and manufacturing cost increases
Solution Approach 1:
The board exterior cover and the molding resin are combined to form an integrated protection structure. The board exterior cover provides the primary protective framework, while the molding resin fills the remaining space and bonds to both the cover and the bare cell, creating a unified structure that uses less material than a separate exterior case would require while maintaining structural stability.
Data Source
AI summary
A secondary battery, sheathes a protection circuit board with a separate cover, connects the sheathed protection circuit board to a bare cell, and executes a molding or hard pack operation with a molding resin member in a space between the protection circuit board and the bare cell. The secondary battery may be constructed with a rechargeable bare cell, a protection circuit board supporting a protection circuit electrically connected to the bare cell and an external terminal, a board exterior cover adhering to the protection circuit board and the board exterior cover exposing the external terminal, and a first lead plate and a second lead plate that electrically connect the bare cell to the protection circuit board.