Secondary Battery Adhesive Finishing Material
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Solution Overview
Problem
Lithium secondary batteries face issues with electrode assembly movement and tab bending due to inadequate adhesion to the case, leading to potential internal short circuits and uneven electrolyte distribution, especially in pouch-type batteries, which compromises safety and appearance.
Innovation Solution
A finishing material with adhesive properties, such as an oriented polystyrene (OPS) film, is attached to the electrode assembly, which develops adhesion upon contact with the electrolyte, enhancing the bonding between the electrode assembly and the case, preventing movement and bending, and improving the case's strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no adhesive material is used between the electrode assembly and the case, then the device complexity is reduced, but the electrode assembly moves inside the case causing safety issues and uneven electrolyte distribution
Solution Approach 1:
The finishing material inherently possesses adhesive properties that are activated upon contact with the electrolyte, eliminating the need for separate adhesive layers or additional fastening mechanisms. The material serves both as a finishing component and an adhesive, reducing structural complexity while ensuring reliable electrode assembly stabilization.
Solution Approach 2:
The adhesive properties of the finishing material are activated through parameter change - specifically, upon contact with the electrolyte, the material transitions from a non-adhesive state to an adhesive state. This dynamic parameter change allows the same material to serve different functions at different stages, avoiding the need for additional adhesive components.
2Reliability
If a traditional adhesive layer requiring thermal activation is used, then the adhesion between electrode assembly and case is improved, but the manufacturing process complexity and energy consumption increase
Solution Approach 1:
The patent replaces thermal activation mechanisms with chemical activation through electrolyte contact. Instead of requiring external heating systems, thermal fields, or energy input equipment, the adhesive activation is achieved through the natural presence of the electrolyte during normal battery operation, significantly simplifying the manufacturing process.
Solution Approach 2:
The electrolyte, which is already present in the battery system for its primary function, simultaneously serves as the activation medium for the adhesive properties of the finishing material. This self-service approach eliminates the need for separate activation systems or additional manufacturing steps.
3Ease of manufacture
If the case is made with weak strength to maintain flexibility, then the ease of manufacture is improved, but the case cannot prevent electrode assembly movement under impact
Solution Approach 1:
The finishing material is pre-installed on the electrode assembly before battery assembly, creating a preliminary adhesive interface. When the electrolyte contacts this pre-positioned material, adhesion is immediately activated, securing the electrode assembly to the case before any impact or movement can occur.
Solution Approach 2:
The finishing material acts as an intermediary between the electrode assembly and the case, providing the adhesive bonding function. This intermediary allows the case itself to maintain its inherent flexibility and ease of manufacture while the finishing material compensates for the lack of structural strength by providing the necessary adhesion.
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 solution effectively stabilizes the electrode assembly, prevents internal short circuits, ensures uniform electrolyte distribution, and enhances the battery's reliability and appearance, particularly in medium- or large-sized batteries, by maintaining alignment and reducing the risk of swelling.
Implementation Method 1
a finishing material having an adhesive property on a surface of an electrode assembly, which can improve the adhesion between the case and the electrode assembly
Implementation Method 2
The surface of the finishing material may be adapted to be chemically changed by the electrolyte so that the finishing material has the adhesive property
Data Source
Figure 1
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AI summary
A secondary battery comprising an electrode assembly (10); a case (20) for accommodating the electrode assembly; an electrolyte in the case; and a material (15) coupled to a surface of the electrode assembly, wherein the material is adapted to develop adhesion to at least a portion of the case .