Battery Case Laser Welding With Local Light Absorption
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Solution Overview
Problem
The manufacturing of power storage devices faces challenges with laser light entering the case due to dimensional tolerances between the case main body and the sealing plate, leading to potential damage of the housed electrode and difficulties in eliminating gaps during the welding process, which compromises safety.
Innovation Solution
A manufacturing method that involves preparing a case main body and a sealing plate, housing the electrode body, and performing laser welding from the outer surface of the sealing plate, with a higher light absorptivity in the area where the opening periphery of the case main body and the sealing plate face each other, preventing laser light from entering the case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser welding is performed on the boundary between case main body and sealing plate, then the case is sealed, but laser light may enter inside the case through gaps caused by dimensional tolerances
Solution Approach 1:
A light-absorbing member is introduced as an intermediary component between the case main body and sealing plate. This member specifically absorbs laser light that would otherwise pass through the gap and enter the case interior, thereby resolving the harmful effect without compromising the sealing function
Solution Approach 2:
The light-absorbing member is positioned only at the specific location where laser light passes through the gap, rather than throughout the entire case structure. This localized approach addresses the specific problem area while maintaining overall structural efficiency
2Object-affected harmful factors
If the radiation angle of laser light is adjusted to prevent laser pass, then laser light entry is reduced, but adjustment is difficult per manufactured individual product
Solution Approach 1:
The light-absorbing member automatically performs the function of preventing laser light entry without requiring external adjustment or intervention. Each product self-regulates the laser light issue through the presence of this member, eliminating the need for per-product angle adjustments
Solution Approach 2:
The problem of laser light entry is extracted from the complex angle adjustment requirement and converted into a simpler solution by introducing a dedicated light-absorbing component that passively handles the issue
3Manufacturing precision
If gap is crushed by clamp to eliminate gap, then gap at certain portion is eliminated, but gaps remain at other welding portions
Solution Approach 1:
The light-absorbing member serves as a mediator that addresses the laser light entry problem without requiring complete gap elimination. It allows the manufacturing process to proceed with existing gaps while still preventing the harmful effect
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 method effectively prevents laser light from entering the case, enhancing the safety and reliability of the power storage device by ensuring proper absorption and absorption of laser light during the welding process.
Implementation Method 1
a light absorptivity of a laser used in the welding step is higher in at least part of an area in which an opening periphery part of the case main body and the sealing plate face each other than at an other portion
Data Source
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AI summary
A manufacturing method of a power storage device disclosed herein includes: a preparing step of preparing a bottomed case main body , a sealing plate , and an electrode body; an assembling step of housing the electrode body inside the case main body, attaching the sealing plate to the opening of the case main body, and assembling the power storage device; and a welding step of radiating laser light to a boundary between the case main body and the sealing plate from a side of an outer surface of the sealing plate, and performing laser welding on the case main body and the sealing plate. A light absorptivity of a laser used in the welding step is higher in at least part of an area in which an opening periphery part of the case main body and the sealing plate face each other than at other portions.