Battery Cover Assembly With Gas-Triggered Current Interruption
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Solution Overview
Problem
Current battery safety mechanisms, such as pull-apart structures, fail to effectively manage gas pressure in extreme conditions like thermal runaway, particularly in early stages of overcharging and with high-activity ternary materials, leading to inadequate protection and potential thermal runaway.
Innovation Solution
A battery cover assembly with a sealed chamber containing a gas-producing medium that disrupts the electrical connection between electrode terminals when pressure exceeds a rated value, using a flipping member and conductive structure to interrupt current flow, enhancing safety by independent gas production and pressure-driven disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pull-apart structure is used to sense gas pressure, then the battery can be protected when pressure is high, but the structure cannot be broken in time in the early stage of overcharging when only a small quantity of gas is produced
Solution Approach 1:
The patent introduces a gas-producing medium into a sealed chamber that is electrically connected to the positive and negative electrodes. This medium preliminarily prepares a gas generation system that will rapidly produce gas when voltage exceeds the rated value, enabling timely disruption of electrical connection before thermal runaway occurs, thus resolving the delay in response time while maintaining protection capability
Solution Approach 2:
The patent changes the parameter of gas production from passive accumulation (relying on battery internal gas generation) to active rapid production (through the gas-producing medium in the sealed chamber). When voltage exceeds the rated value, the gas-producing medium rapidly generates large volume of gas, creating immediate pressure to flip the flip sheet and interrupt current, thus improving both response time and protection reliability
2Stability of the object's composition
If the pull-apart pressure is set high, then the structure is more stable, but the starting pressure increases and the structure cannot be broken in time; if the pull-apart pressure is set low, then the structure can break easily, but it may be broken in case the battery is injected with liquid and stored at high temperature
Solution Approach 1:
The patent introduces a gas-producing medium as an intermediary between the electrical connection and the pull-apart structure. This medium mediates the triggering process by converting electrical voltage excess into rapid gas production, which then creates pressure to flip the flip sheet. This intermediary mechanism ensures that only significant voltage excess (exceeding rated value) triggers the protection, preventing false triggering from minor conditions like liquid injection or high temperature storage, while maintaining structural stability
Solution Approach 2:
The patent changes the pressure generation mechanism from direct mechanical pressure (relying on battery internal pressure) to chemical/gas pressure (through the gas-producing medium). The gas-producing medium rapidly generates large volume of gas when voltage exceeds the rated value, creating immediate and significant pressure to overcome the pull-apart structure's stability threshold, thus resolving the contradiction between structural stability and timely breaking
3Reliability
If a pull-apart structure is used for current interruption, then the circuit can be disconnected, but the reactions between materials inside the battery cannot be stopped when the battery is in thermal runaway state
Solution Approach 1:
The patent introduces a gas-producing medium into a sealed chamber that is electrically connected to the positive and negative electrodes. This medium preliminarily prepares a gas generation system that will rapidly produce gas when voltage exceeds the rated value, enabling timely disruption of electrical connection before thermal runaway occurs, thus resolving the delay in response time while maintaining protection capability
Solution Approach 2:
The patent replaces the traditional mechanical pull-apart structure with a gas pressure-driven system. The gas-producing medium rapidly generates gas that creates pressure to flip the flip sheet, which then disrupts the electrical connection. This substitution enables faster response and more reliable current interruption, preventing thermal runaway by cutting off the electrical circuit before uncontrolled reactions can occur
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 ensures timely disconnection of current in the battery, improving safety by addressing the limitations of existing mechanisms, particularly in early thermal runaway scenarios and with high-activity materials, without adverse effects on battery capacity or life.
Implementation Method 1
when a voltage difference between the positive and negative electrodes of the battery exceeds a rated value, the gas-producing medium is capable of producing gas, to disrupt the electrical connection between the electrode inner terminal and the electrode outer terminal under the action of the pressure of the gas
Data Source
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AI summary
The present disclosure relates to a battery cover assembly, a battery cell, a battery module, a power battery pack and an electric vehicle. The battery cover assembly includes a cover plate 104, an electrode inner terminal and an electrode outer terminal. The electrode inner terminal is electrically connected to the electrode outer terminal through a current interrupt structure disposed on the cover plate 104. The current interrupt structure includes a sealed chamber 103 configured to fill a gas-producing medium therein. The sealed chamber 103 is configured to make the gas-producing medium to be electrically connected to positive electrodes and negative electrodes of a battery. When a voltage difference between the positive electrodes and negative electrodes of the battery exceeds a rated value, the gas-producing medium is capable of producing gas, to disrupt the electrical connection between the electrode inner terminal and the electrode outer terminal under the action of the pressure of the gas. That is, gas production in the sealed chamber in the cover assembly is independent of gas production inside the battery, so that gas pressure can be formed for the current interrupt structure in time to activate the current interrupt structure in time, thereby improving the battery safety.