Battery Cell Thickness Control via Pressurizing Jig Disconnection
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Solution Overview
Problem
The challenge is to improve energy density in battery cells by controlling the thickness variation when a pressurizing jig is disconnected, as the pop-up phenomenon increases cell thickness, reducing energy density during the battery activation process.
Innovation Solution
A battery cell design with a negative electrode containing a silicon-based active material and a graphite active material, along with a separation film, where the pressurizing jig is disconnected at a specific state of charge to minimize thickness variation, ensuring a variation ratio of less than 0.009, thereby stabilizing the cell thickness and enhancing energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a pressurizing jig is used during battery activation to suppress cell thickness increase, then cell thickness is controlled during activation, but the cell experiences a pop-up phenomenon when the pressurizing jig is disconnected, substantially increasing cell thickness and reducing energy density
Solution Approach 1:
The patent applies preliminary action by performing a thickness compensation process before the cell is finalized. Specifically, after the pressurizing jig is disconnected and the pop-up phenomenon occurs, the cell is placed in a compensation jig that applies controlled pressure to reduce the thickness increase. This preliminary correction ensures that the final cell thickness meets specifications, resolving the contradiction between maintaining thickness control during activation and preventing energy density loss from the pop-up phenomenon.
2Productivity
If the pressurizing jig is disconnected after battery activation to complete manufacturing, then the manufacturing process can be finalized, but the cell thickness substantially increases due to the pop-up phenomenon, reducing energy density
Solution Approach 1:
The compensation process is performed as a preliminary action before the cell is considered complete. The method includes placing the cell in a compensation jig, applying controlled pressure for a predetermined time, and measuring thickness to ensure it meets specifications. This preliminary correction allows the manufacturing process to be completed while ensuring the final cell thickness and energy density meet requirements.
Solution Approach 2:
The patent converts the harmful pop-up phenomenon into a beneficial process by utilizing the cell's elastic recovery characteristics. The compensation jig applies controlled pressure that allows the cell to gradually return to its original thickness, transforming the potential defect of thickness increase into an opportunity for precise thickness control and quality assurance.
Data Source
AI summary
A battery cell includes a positive electrode, a negative electrode, and a separation film provided between the positive electrode and the negative electrode. A variation ratio of thickness of a battery cell before a pressurizing jig is disconnected and after the pressurizing jig is disconnected is equal to or less than 0.009, and the variation ratio of thickness of a battery cell is defied by a value generated by dividing a variation value of thickness that is a difference between the thickness of a battery cell after the pressurizing jig is disconnected and the thickness of a battery cell before the pressurizing jig is disconnected by the thickness of a battery cell before the pressurizing jig is disconnected.