Pouch Forming Device Dynamic Stripping to Prevent Vertex Cracks
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Solution Overview
Problem
Existing secondary battery pouch forming devices often result in cracks at the vertex portion of the accommodation part due to uneven elongation during the formation process, leading to quality issues in the battery casing.
Innovation Solution
A pouch forming device with a control member that gradually reduces the pressing force of the stripper and descending speed of the punch, using a detection sensor to control the movement of the stripper and punch, ensuring stable elongation and preventing cracks by adjusting the pressing force and speed during the formation of the electrode assembly accommodation part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the stripper presses and fixes the pouch film with constant pressing force during the forming process, then the pouch film is securely fixed for forming, but cracks occur at the vertex portion due to insufficient elongation
Solution Approach 1:
The pressing force of the stripper is changed from constant to dynamic/gradually decreasing. The control member gradually decreases the pressing force of the stripper as the punch descends and the forming process progresses, allowing the pouch film to elongate gradually and prevent cracks at the vertex portion while maintaining forming precision.
Solution Approach 2:
The pressing force parameter of the stripper is changed during the forming process. The control member adjusts the pressing force from high (when punch is at upper position) to low (when punch is at lower position), enabling the pouch film to elongate progressively and avoid crack formation while achieving precise forming.
2Productivity
If the punch descends at constant speed to form the accommodation part, then the forming process is simple and fast, but cracks occur due to sudden elongation of the pouch film
Solution Approach 1:
The descending speed of the punch is changed from constant to dynamic/gradually decreasing. The control member gradually decreases the descending speed of the punch as the forming process progresses, allowing the pouch film to elongate gradually rather than suddenly, preventing cracks while maintaining efficient forming speed.
Solution Approach 2:
The descending speed parameter of the punch is changed during the forming process. The control member adjusts the speed from high (at the beginning of descent) to low (near the end of forming), enabling controlled elongation of the pouch film and prevention of cracks while preserving overall productivity.
3Strength
If the stripper pressing force is suddenly reduced when the punch is inserted, then elongation increases quickly, but the pouch film becomes unstable and forming precision decreases
Solution Approach 1:
The pressing force reduction is implemented dynamically and gradually rather than suddenly. The control member controls the stripper to gradually decrease pressing force as the punch descends, allowing the pouch film to elongate progressively while maintaining stability and forming precision throughout the process.
Solution Approach 2:
The gradual reduction of pressing force is prepared in advance through the control member's control logic. As the punch approaches and during insertion, the control member progressively reduces the stripper's pressing force, ensuring stable and controlled elongation rather than sudden release that would cause instability.
Data Source
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AI summary
Provided is a pouch forming device. The pouch forming device comprises a die member provided with a die on which a pouch film is disposed on a top surface thereof, in which a forming part is formed, and a die holder to which the die is fixed, a stripper member pressing and fixing the pouch film disposed on the die when descending and a first driving piece allowing the stripper to vertically move, a punch member provided with a punch plate comprising a punch inserted into the forming part to form an electrode assembly accommodation part in the pouch film and a second driving piece allowing the punch plate to vertically move, and a control member controlling the first driving piece to allow the stripper to ascend when the punch is inserted into the forming part to press the pouch film so as to decrease in pressing force applied to the pouch film.