Battery Insulation Sheet Structure for Welding Glare and Heat Blocking
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Solution Overview
Problem
Secondary batteries face challenges in blocking thermal conduction between the electrode assembly and cap plate, preventing light reflection during welding, maintaining static electricity, and ensuring alignment and foreign matter detection post-welding.
Innovation Solution
The secondary battery design incorporates an insulation sheet with distinct regions, including a light-transmitting polypropylene layer for visibility inspection, a conductive polyethylene or polypropylene layer for static prevention, and a white polypropylene layer to block light reflection, all integrated within a case and cap assembly to address these issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an insulation sheet is used to block thermal conduction between the electrode assembly and cap plate, then thermal insulation is improved, but the sheet may reflect light during welding causing inspection difficulties
Solution Approach 1:
The insulation sheet is designed with different regions having different properties: a first region with light-blocking capability to prevent light reflection during welding, and a second region with light-transmitting capability to allow vision inspection. This local differentiation resolves the contradiction by applying different optical properties to different areas of the same insulation sheet.
Solution Approach 2:
The insulation sheet comprises a composite structure with multiple layers including a light-blocking layer and a light-transmitting layer. This composite material design allows the sheet to simultaneously achieve thermal insulation, prevent light reflection in certain areas, and permit light transmission in other areas for inspection purposes.
2Object-affected harmful factors
If a light-blocking layer is added to prevent light reflection during welding, then light reflection is reduced, but the sheet becomes less transparent for vision inspection
Solution Approach 1:
The insulation sheet is segmented into distinct functional regions: a first region containing a light-blocking layer to prevent light reflection during welding, and a second region without the light-blocking layer to maintain light transmission for vision inspection. This segmentation allows both functions to coexist without compromising either.
Solution Approach 2:
Different regions of the insulation sheet are assigned different optical properties: the first region has light-blocking characteristics to prevent reflection during welding operations, while the second region maintains light-transmitting properties to enable vision inspection for foreign matter detection.
3Difficulty of detecting and measuring
If the insulation sheet is made completely transparent for vision inspection, then foreign matter detection is improved, but light reflection during welding increases
Solution Approach 1:
The insulation sheet is divided into a first region with light-blocking properties to prevent light reflection during welding, and a second region with light-transmitting properties to enable vision inspection for foreign matter detection. This spatial segmentation resolves the contradiction by allowing both functions in different areas.
Solution Approach 2:
The insulation sheet exhibits local quality differentiation where the first region contains a light-blocking layer to prevent light reflection during welding operations, while the second region remains transparent to allow vision inspection for detecting foreign matter.
4Reliability
If multiple layers are added to the insulation sheet to achieve multiple functions, then functional performance is improved, but device complexity increases
Solution Approach 1:
The insulation sheet is constructed as a composite material structure with a base layer and a light-blocking layer in the first region. This composite design enables the sheet to simultaneously provide thermal insulation, electrical insulation, light blocking, and light transmission functions across different regions.
Solution Approach 2:
The insulation sheet is designed as a multi-functional component that simultaneously provides thermal insulation, electrical insulation, light blocking during welding, and light transmission for inspection. This universal design consolidates multiple functions into a single component, improving reliability without proportionally increasing complexity.
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 blocks thermal conduction, prevents light reflection, maintains static electricity, and allows for vision-based foreign matter inspection, ensuring proper alignment and assembly quality.
Implementation Method 1
a first sheet part that is capable of transmitting light
Implementation Method 2
a fourth sheet part that is in close contact with the inner surface of the first sheet part and includes a conductive material
Implementation Method 3
a third sheet part that is in close contact with the inner surface of the fourth sheet part and is made of a material different from that of the second sheet part
Data Source
AI summary
The present invention relates to a secondary battery in which a first region and a second region of an insulation sheet are made of different materials, and thus thermal conduction between an electrode assembly and a cap plate can be blocked, light reflection that may occur during welding can be prevented, and static electricity and alignment can be maintained. Disclosed in one embodiment is a secondary battery comprising: an electrode assembly having a first electrode tab and a second electrode tab; a first terminal electrically connected to the first electrode tab of the electrode assembly; an insulation sheet having a first region covering the upper side of the electrode assembly and a second region covering both long sides of the electrode assembly; a case accommodating the electrode assembly, the first terminal, and the insulating sheet; and a cap plate sealing an top opening of the case, wherein in the insulation sheet, the first region further includes a material layer different from that of a second region, and consists of four layers.