Can-Type Secondary Battery Formation to Prevent Electrode Swelling
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Solution Overview
Problem
The swelling phenomenon of the electrode assembly in can-type secondary batteries due to gas trapped within the battery case during the formation process, which affects the thickness and manufacturing efficiency.
Innovation Solution
A method involving the application of sequential pressures during the formation process of can-type secondary batteries, including a primary and secondary pressure stage, while maintaining the injection hole open to discharge gas, followed by secondary electrolyte injection and closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the injection hole is closed after electrolyte injection and formation process is performed, then the manufacturing process can be completed within predetermined time, but gas remains trapped causing electrode assembly swelling
Solution Approach 1:
The injection hole is kept open during the formation process as a preliminary measure to allow gas to escape. This preliminary action prevents gas accumulation before it can cause swelling, enabling the hole to be closed afterward without compromising electrode assembly flatness.
Solution Approach 2:
The formation process naturally generates gas as a harmful byproduct, but the invention converts this harmful effect into a benefit by utilizing the gas generation period to simultaneously perform degassing. The gas that would normally cause swelling is instead channeled out through the open injection hole, turning a problem into a solution.
2Manufacturing precision
If the injection hole is kept open during formation process to discharge gas, then electrode assembly swelling is prevented, but the injection hole must remain open extending process time
Solution Approach 1:
Instead of keeping the injection hole open for the entire formation process, the invention applies partial action by opening it only during the specific time window when gas is generated and needs to be discharged. Once gas discharge is complete, the hole is closed, avoiding unnecessary extension of process time.
3Quantity of substance
If secondary electrolyte is injected after formation process, then complete electrolyte filling is achieved, but additional process steps are required
Solution Approach 1:
The invention merges the electrolyte injection process with the formation process by keeping the injection hole open throughout. This allows the formation process to serve dual purposes: both forming the electrode structure and enabling electrolyte filling, thereby eliminating the need for a separate secondary electrolyte injection step.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively discharges gas to prevent electrode assembly swelling and allows for efficient lamination of stack-type electrode assemblies within the can-type battery case, enhancing energy density and reducing manufacturing time.
Implementation Method 1
a pressure is applied to the battery case (12) while performing a formation process
Data Source
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AI summary
A method for manufacturing a secondary battery according to an embodiment of the present invention for achieving the above object includes: accommodating an electrode assembly, in which electrodes and separators are alternately stacked, in a can type battery case; primarily injecting an electrolyte through an injection hole; applying a pressure to the battery case while performing a formation process in a state in which the injection hole is opened; secondarily injecting the electrolyte through the injection hole; and closing the injection hole.