Secondary Battery Adhesive Tape Electrode Stability
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Solution Overview
Problem
Secondary batteries face issues with electrode assembly movement inside the case due to external vibrations or impacts, leading to increased internal resistance and potential damage to electrode tabs.
Innovation Solution
A secondary battery design featuring a tape with a base layer that exhibits adhesive properties when contacting the electrolyte, attaching to the electrode assembly and case, preventing movement by adhering to the inner surface of the case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealing tape is used to prevent electrode assembly movement, then the electrode assembly is secured to the case, but the tape absorbs electrolyte and swells causing welding parts to disconnect
Solution Approach 1:
The patent changes the material parameters of the adhesive layer by selecting a polymer with specific glass transition temperature (Tg) range (-50°C to 0°C) and controlled electrolyte affinity. This parameter optimization allows the adhesive to provide strong bonding without excessive swelling when exposed to electrolyte, thus preventing welding part disconnection while maintaining electrode assembly stability.
Solution Approach 2:
The patent uses a composite adhesive layer made from specific polymer materials (such as polyacrylic acid or polyacrylamide derivatives) that combine multiple properties: adequate electrolyte wettability for adhesion, controlled swelling behavior, and appropriate Tg range. This composite material approach resolves the contradiction between needing strong adhesion and avoiding harmful swelling effects.
2Strength
If the sealing tape material has high affinity for electrolyte to ensure adhesion, then the electrode assembly attaches firmly to the case, but the tape swells excessively causing welding parts to disconnect
Solution Approach 1:
The patent optimizes the polymer's glass transition temperature (Tg) to be within -50°C to 0°C, which controls the chain mobility and swelling behavior of the adhesive layer. This parameter change enables the adhesive to maintain strong bonding strength while limiting excessive swelling when exposed to electrolyte, thus preserving both adhesion strength and dimensional stability.
Solution Approach 2:
The patent applies local quality control by designing the adhesive layer with specific material properties (polymer type, Tg range, thickness of 1-10 μm) that are optimized for the specific function of bonding the electrode assembly to the case. The adhesive layer's composition is tailored to provide adequate electrolyte wettability for adhesion while maintaining local dimensional stability to prevent welding part disconnection.
3Object-generated harmful factors
If a non-adhesive tape is used to avoid swelling issues, then welding parts remain connected, but the electrode assembly cannot be secured against movement
Solution Approach 1:
The patent changes the adhesive properties of the tape by selecting polymer materials with specific Tg ranges and electrolyte affinities. This enables the tape to provide just enough adhesion to secure the electrode assembly against movement while controlling swelling to prevent welding part disconnection, thus simultaneously achieving both electrode stability and welding part connection.
Solution Approach 2:
The adhesive layer acts as an intermediary between the electrode assembly and the case, providing a controlled interface that allows for secure bonding without excessive swelling. The adhesive material serves as a mediator that balances the competing requirements of adhesion strength and dimensional stability, enabling the electrode assembly to be firmly attached while preventing welding part disconnection.
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 adhesive tape effectively secures the electrode assembly within the case, reducing movement and associated damage, thereby maintaining battery performance and extending its lifespan.
Implementation Method 1
the base layer has at least a portion exhibiting an adhesive property when contacting the electrolyte
Implementation Method 2
When the base layer contacts the electrolyte, at least a portion of the base layer may shrink and exhibit an adhesive property
Data Source
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AI summary
A secondary battery is disclosed. In one embodiment, the battery includes i) an electrode assembly, ii) an electrolyte, iii) a tape attached to at least part of an outer surface of the electrode assembly and iv) a case accommodating the electrode assembly, electrolyte and tape. The tape includes a base layer, and wherein at least a portion of the base layer is configured to exhibit an adhesive property when contacting the electrolyte so as to contact an inner surface of the case.