Secondary Battery Gas Discharge Device for Can-Type Cell Formation
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Solution Overview
Problem
Can type secondary batteries face challenges in discharging gases during the manufacturing process, leading to incomplete gas removal and increased thickness due to retained gases, which hinders efficient initial charging and prolongs assembly time.
Innovation Solution
A gas discharge device is integrated into the battery case, featuring a switch, gasket, and restoring part that allows for selective opening and closing of a gas discharge hole, enabling easy discharge of gases during both pre-formation and formation processes, even after the assembly process is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the injection hole is completely sealed after electrolyte injection in can type secondary batteries, then moisture permeation is prevented, but gas discharge becomes impossible and gas remains within the case increasing battery thickness
Solution Approach 1:
A gas discharge device is introduced as an intermediary component between the sealed battery case and the external environment. This device includes a gas discharge hole that allows gas to escape while maintaining the sealed structure's moisture protection capabilities. The device acts as a mediator that resolves the contradiction by providing a controlled pathway for gas discharge without compromising the overall seal integrity.
Solution Approach 2:
The sealing system is segmented into two functional parts: the main sealed structure that prevents moisture permeation, and the gas discharge device that handles gas removal. This segmentation allows each component to perform its specific function independently - the sealed structure maintains reliability while the gas discharge device eliminates harmful gas accumulation.
2Object-generated harmful factors
If pre-formation process is performed in a dry room before injection hole closure, then gas discharge is enabled, but assembly time increases and manufacturing efficiency decreases
Solution Approach 1:
The gas discharge device is pre-installed and positioned within the battery case during the assembly process, before the injection hole is sealed. This preliminary action ensures that the gas discharge pathway is already in place, eliminating the need for separate pre-formation gas discharge steps in the dry room and reducing overall assembly time.
Solution Approach 2:
The gas discharge function is merged into the main assembly process by integrating the gas discharge device installation with the battery case assembly. Instead of performing gas discharge as a separate subsequent step, the device is installed concurrently with other assembly operations, combining multiple functions into a unified process flow.
3Productivity
If formation process is performed after injection hole closure, then charging rate is high, but no gas discharge method exists and battery thickness increases
Solution Approach 1:
The gas discharge device serves as a mediator that enables high-rate formation charging by providing a gas escape pathway. This allows the formation process to proceed at high charging rates without gas accumulation, as the device mediates between the high charging rate input and the need to prevent thickness increase by removing generated gas.
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
This solution reduces assembly time, enhances initial charging rates, and ensures complete gas discharge, preventing battery thickness increase by allowing easy manipulation of the gas discharge device to remove gases, thereby improving manufacturing efficiency.
Implementation Method 1
a restoring part configured to restore a position of the switch when the external force is removed, thereby closing the gas discharge hole
Data Source
AI summary
To solve the above-described objects, a method for manufacturing a secondary battery according to an embodiment of the present invention comprises: manufacturing an electrode assembly in which electrodes and a separator are alternately stacked; inserting the electrode assembly into a battery case through an opening; covering the opening of the battery case; injecting an electrolyte into the battery case through an injection hole formed in the battery case; closing the injection hole; performing a pre-formation process; and applying external force to a switch of a gas discharge device formed on one surface of the battery case, thereby linearly moving a gasket of the gas discharge device and opening a gas discharge hole, such that a first gas generated in the battery case is discharged to an outside of the battery case during the performing of the pre-formation process.