Pouch Battery CID Overcharging Safety Mechanism
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Solution Overview
Problem
Secondary batteries face high ignition risks due to overcharging, which generates flammable gas inside the battery, especially as their size and capacity increase, necessitating a technology to safely discharge this gas and prevent overcharging.
Innovation Solution
A pouch battery design incorporating a current interrupt device (CID) that changes shape with internal pressure to disconnect the electrical connection and discharge generated gas outside, incorporating an electrode assembly, pouch, connecting terminals, and a lead tab to prevent overcharging and release gas safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the size and capacity of secondary batteries are increased to meet high energy demand, then energy storage capability is improved, but the ignition risk due to overcharging increases
Solution Approach 1:
A current interrupt device (CID) is introduced as an intermediary safety mechanism between the electrode assembly and external circuitry. The CID includes a movable contact that acts as a mediator to interrupt current flow when overpressure is detected, preventing the harmful effect of overcharging in high-capacity batteries without reducing their energy storage capability
Solution Approach 2:
The harmful overpressure generated during overcharging is converted into a beneficial safety signal. The increased internal pressure caused by gas generation during overcharging automatically triggers the CID mechanism, causing the movable contact to separate and interrupt the circuit, thereby transforming the harmful effect into a protective action
2Reliability
If a current interrupt device is added to stop overcharging, then safety is improved, but device complexity increases
Solution Approach 1:
The CID components (movable contact, spring, and housing) are merged into a single integrated assembly that is electrically connected in series with the electrode assembly. This unified structure eliminates the need for separate control circuits and multiple discrete components, achieving overcharging protection without significantly increasing overall device complexity
Solution Approach 2:
The CID is designed as a self-actuating mechanism that automatically responds to overpressure conditions without requiring external control systems. The spring-loaded movable contact self-adjusts based on internal pressure, opening the circuit when needed and closing it during normal operation, thereby providing safety functionality without adding complex control logic
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
The solution effectively reduces the ignition risk by cutting off current flow and discharging gas generated during overcharging, enhancing safety at the battery cell level while minimizing configuration complexity and part count.
Implementation Method 1
a current interrupt device (CID) configured to be received in the pouch and have a shape changed according to a change in internal pressure of the pouch to separate the connecting terminal from the electrode assembly
Implementation Method 2
capable of discharging gas generated inside a pouch at the time of overcharging to the outside so as to reduce an ignition risk due to the overcharging
Data Source
AI summary
A pouch battery having improved overcharging safety includes a CID interrupting an electrical connection between an electrode assembly and a lead tab when the pouch is expanded. When the pouch is expanded, the CID discharges gas generated inside the pouch to the outside, and at the time of overcharging a secondary battery, the CID interrupts a flow of current introduced into the secondary battery and discharges the gas generated due to the overcharging to the outside of the pouch, thereby reducing an ignition risk and improving the overcharging safety.