Sealed Battery Current Interrupting Device Reducing Shearing Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pressure-type current interrupting devices in sealed batteries face issues with high shearing stress on the reversing plate when activated, leading to potential weld fracture due to internal pressure increases.
Innovation Solution
The design includes a conductive member with a recessed shape and a reversing plate joined to its inner peripheral surface, featuring a gap between the upper surface of the reversing plate and the conductive member to prevent direct contact and reduce shearing stress, along with specific welding techniques like lap welding to minimize contraction stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reversing plate is joined to the conductive member by welding to ensure electrical connection, then electrical conductivity is improved, but shearing stress on the weld increases during activation
Solution Approach 1:
The patent introduces an intermediary gap structure between the reversing plate and conductive member that redirects the stress path. During activation, the reversing plate deforms and contacts the conductive member at specific points, while the gap prevents direct transmission of shearing stress to the weld, thus protecting the electrical connection while maintaining functionality
Solution Approach 2:
The patent changes the geometric parameters of the joining structure by creating a gap between the reversing plate and conductive member. This parameter change allows the system to accommodate deformation during activation without transmitting excessive shearing stress to the weld, thereby maintaining both electrical connection and weld integrity
2Reliability
If the reversing plate deforms under internal pressure to interrupt current, then current interruption function is achieved, but shearing stress on the reversing plate increases
Solution Approach 1:
The gap structure acts as a stress-redistributing intermediary that allows the reversing plate to deform freely under internal pressure without developing excessive shearing stress. The gap prevents constraint-induced stress concentration while still enabling the current interruption function through plate deformation
3Reliability
If the entire circumference of the reversing plate is joined to the conductive member to ensure electrical connection, then electrical conductivity is improved, but contraction stress from welding increases
Solution Approach 1:
The gap structure serves as a stress-relieving intermediary that interrupts the continuous weld path around the entire circumference. This prevents the accumulation of contraction stress that would occur with complete circumferential welding, while still maintaining adequate electrical connection through controlled contact points
Solution Approach 2:
The patent extracts or removes the welding from the entire circumference of the reversing plate, retaining it only at specific locations. This selective extraction of the joining method reduces the total weld length and consequently the total contraction stress while maintaining sufficient electrical connection
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 configuration effectively reduces shearing stress on the reversing plate during activation, preventing weld fracture and ensuring reliable current interruption in sealed batteries.
Implementation Method 1
If the pressure inside the battery case becomes higher than a set pressure due to some sort of abnormality, internal pressure P is applied to the reversing plate 550, causing the reversing plate 550 to deform in such a way that it bends upward.
Implementation Method 2
internal pressure P is applied to the reversing plate 550, causing the reversing plate 550 to deform in such a way that it bends upward
Implementation Method 3
The entire circumference of an edge portion of the reversing plate 550 is joined by welding to an inner peripheral surface of the receiving portion 544 of the rivet 540.
Data Source
AI summary
A current interrupting device of a sealed battery includes a conductive member that is electrically connected to an external terminal of a battery case; a collector terminal that is arranged inside the battery case; and a reversing plate that is interposed between the conductive member and the collector terminal, and that electrically cuts off the conductive member from the collector terminal by deforming in response to an increase in pressure inside the battery case. An inner peripheral surface of the conductive member is joined to an outer peripheral surface of the reversing plate. An upper surface of the reversing plate does not contact the conductive member regardless of an activation of the current interrupting device.