Secondary Battery Protuberance Sealing Structure
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Solution Overview
Problem
Conventional pouch-shaped secondary batteries face issues with low sealing force and potential damage to the electrode assembly due to molten material during thermal welding, leading to defects and reduced durability.
Innovation Solution
A secondary battery design featuring a protuberance at the outer edge of the electrode assembly receiving part, which protrudes upward and downward, preventing molten material from contacting the electrode assembly by accommodating it along the edge in a curved or straight line, thereby enhancing sealing efficiency and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal welding is performed to seal the battery case, then sealing strength is improved, but molten material damages the electrode assembly
Solution Approach 1:
The patent introduces a shielding structure (metal foil or insulating material) as an intermediary between the molten material and the electrode assembly. This intermediary layer receives the molten material during thermal welding, preventing direct contact with the electrode assembly while allowing the welding process to proceed effectively, thus resolving the contradiction between achieving strong sealing and preventing damage to the electrode assembly
Solution Approach 2:
The patent segments the battery case structure by adding a separate shielding component (metal foil or insulating material) that is disposed between the electrode assembly and the battery case wall. This segmentation allows the sealing process to occur independently from the electrode assembly, enabling strong sealing without direct transmission of molten material damage to the electrode assembly
2Ease of manufacture
If pouch-shaped battery case is used, then manufacturing cost and weight are reduced, but sealing force is insufficient causing electrolyte leakage
Solution Approach 1:
The patent employs composite material structure for the battery case, combining the lightweight pouch-shaped laminate (providing cost and weight advantages) with additional sealing reinforcement elements such as metal foils or insulating materials (providing enhanced sealing force). This composite approach allows the battery case to maintain the economic benefits of pouch design while achieving the sealing reliability needed to prevent electrolyte leakage
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
The protuberance effectively blocks surplus molten material from reaching the electrode assembly, improving sealing strength, reducing defects, and enhancing the overall safety and durability of the battery.
Implementation Method 1
an outer edge sealed portion of an electrode assembly receiving part is pressed by a high-temperature sealing tool such that inner sealant layers, which have a low melting point, are welded and bonded to each other
Data Source
AI summary
Disclosed herein is a plate-shaped secondary battery configured to have a structure in which an electrode assembly of a cathode/separator/anode structure is mounted in a battery case in a sealed state by thermal welding, wherein a protuberance is formed at an outer edge sealed portion of an electrode assembly receiving part of the battery case such that the protuberance protrudes upward and downward from the sealed portion, and the protuberance extends along the outer edge of the electrode assembly receiving part continuously in a curved line or in a straight line in a state in which the protuberance is adjacent to the electrode assembly receiving part.