Sealed Battery Current Interrupt Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Sealed batteries, particularly lithium-ion secondary batteries for electric vehicles, face challenges with increasing battery capacity leading to higher internal pressure due to gas generation during normal charge and discharge operations, which complicates the activation of current interrupt mechanisms and hinders the effectiveness of safety and relief valves.
Innovation Solution
A new current interrupt mechanism is introduced, featuring a partitioned battery case with a second electrolyte solution containing a gas-generating addition agent, which activates the current interrupt when internal pressure exceeds a predetermined level, separate from the safety and relief valves, allowing for appropriate overcharge protection without interfering with existing valve mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a relief valve is provided to manage internal pressure from gas accumulation during normal operation, then internal pressure can be kept at a certain level, but the current interrupt mechanism cannot be activated appropriately because the relief valve opens at a pressure lower than the activation pressure of the current interrupt mechanism
Solution Approach 1:
The battery case is divided into a first space enclosing the electrode assembly and a second space enclosing the current interrupt mechanism, separated by a partition. This segmentation allows the current interrupt mechanism to respond to pressure from gas generated in the second space without being affected by the relief valve's operation in the first space.
Solution Approach 2:
A partition acts as an intermediary structure between the first space (with relief valve) and the second space (with current interrupt mechanism). The partition includes a current path portion that allows electrical connection while physically separating the two spaces, enabling independent pressure management in each space.
2Quantity of substance
If the battery case interior space is reduced to increase battery capacity, then more active material can be contained, but the volume of dead space is reduced, causing internal pressure to increase more quickly during normal charge and discharge operations
Solution Approach 1:
The battery case is segmented into a first space for the electrode assembly and a second space for the current interrupt mechanism and gas-generating electrolyte. This segmentation creates dedicated space for gas accumulation in the second space, preventing pressure buildup in the first space while maintaining high battery capacity.
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 effectively manages internal pressure by activating the current interrupt mechanism during overcharge events, preventing damage to the battery case while maintaining low resistance and ensuring safe operation by isolating the gas-generating agent from the primary battery reaction space.
Implementation Method 1
the second electrolyte solution contains an addition agent generating a gas when a predetermined voltage is applied to the second electrolyte solution
Data Source
AI summary
A current interrupt mechanism includes a partition wall defining a second space that is independent from a first space, and the partition wall includes a current path portion serving as a current path of a sealed battery. The current interrupt mechanism interrupts the current path in response to an internal pressure of the second space that is higher than a predetermined pressure. One conductive path passes through the current path of the current interrupt mechanism, and is in contact with the second electrolyte solution enclosed in the second space. Another conductive path includes a potential application line that is wired to the second electrolyte solution enclosed in the second space.