Battery Case Laser Sealing With Gap Light Absorption
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Solution Overview
Problem
The manufacturing of power storage devices faces challenges with laser light entering the case through gaps between the case main body and the sealing plate during the welding process, leading to potential damage of the housed electrode body and difficulties in eliminating gaps uniformly, 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 to prevent laser light from entering the case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser welding is performed on the boundary between case main body and sealing plate, then welding strength is improved, but laser light may enter inside the case through gaps causing damage to electrode body
Solution Approach 1:
A light-absorbing member is introduced as an intermediary component between the laser light path and the electrode body. This member is positioned in the gap between the case main body and sealing plate specifically at areas where laser light might pass through, absorbing the laser energy and preventing it from reaching and damaging the electrode body inside the case.
Solution Approach 2:
The invention converts the potentially harmful laser light that would otherwise damage the electrode body into a beneficial effect by using it to heat and weld the case main body and sealing plate together. The light-absorbing member facilitates this by absorbing the laser energy and converting it to thermal energy for welding, while also blocking any stray light from reaching the electrode body.
2Reliability
If dimensional tolerance of case main body and sealing plate is reduced to eliminate gaps, then safety is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The light-absorbing member acts as a simple, inexpensive, and easily replaceable component that addresses the safety issue without requiring high-precision manufacturing of the case main body or sealing plate. This component can be mass-produced at low cost and installed in the gap, providing a practical solution that avoids the complexity and expense of reducing dimensional tolerances of the main structural parts.
3Reliability
If radiation angle of laser light is adjusted to prevent laser pass, then safety is improved, but productivity decreases due to frequent adjustments
Solution Approach 1:
The light-absorbing member is pre-installed in the gap between the case main body and sealing plate before the laser welding process begins. This preliminary placement ensures that any laser light that might pass through the gap is absorbed, eliminating the need for frequent adjustments of the radiation angle during welding operations and maintaining high productivity.
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
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.