Sealed Battery Laser Welding Heat Insulation
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Solution Overview
Problem
Welding faults occur in sealed batteries due to rapid gas expansion and melting of sealing components during laser welding, caused by the minute space defined by the recess, sealing plug, and sealing plate.
Innovation Solution
A heat insulating member with lower heat conductivity than the case and sealing members is placed in the minute space to block the boundary portion between the sealing members, minimizing heat conduction and preventing rapid gas expansion and melting during laser welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a minute space is defined by the recess, sealing plug, and sealing plate to seal the pouring hole, then the sealing reliability is improved, but gas expansion and melting occur during laser welding causing welding faults
Solution Approach 1:
A heat insulating member is introduced as an intermediary component into the minute space between the sealing plug and sealing plate. This heat insulating member has lower heat conductivity than both the case and sealing members, serving as a thermal barrier that prevents rapid heat transmission during laser welding, thereby suppressing gas expansion and melting while maintaining sealing effectiveness
Solution Approach 2:
The heat conductivity parameter of the material in the minute space is changed by introducing a heat insulating member with specifically lower heat conductivity compared to the case and sealing members. This parameter change creates a thermal gradient that controls heat flow during welding, preventing the harmful effects of rapid heating while preserving the sealing function
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 approach effectively suppresses welding faults by reducing heat conduction and gas expansion, ensuring a reliable seal of the battery case.
Implementation Method 1
a heat insulating member having a lower heat conductivity than each of heat conductivities of the case and the second sealing member is provided in a minute space defined by the recess, the first sealing member and the second sealing member
Implementation Method 2
a welding step for continuously joining an outer circumferential surface of the second sealing member inserted into the recess to an inner circumferential surface of the recess throughout circumferences of the outer circumferential surface and the inner circumferential surface by laser welding
Data Source
AI summary
Provided is a technique for suppressing welding faults caused in sealing a case of a sealed battery by laser welding. A step for manufacturing a sealed battery having a case sealed by a sealing plug and a sealing plate, which includes a sealing step for fitting the sealing plug into a pouring hole formed in a recess of a lid portion and inserting the sealing plate into the recess, and a welding step for joining the sealing plate to the recess by laser welding. In the sealing step, a heat-insulating member is provided in a minute space defined by the recess, the sealing plug and the sealing plate so as to block at least a part of the boundary portion between the sealing plate and the recess. In the welding step, welding is completed at a position where the heat-insulating member is present in the boundary portion.