Battery Cell Pouch Laminate for Higher Electrolyte Peel Strength
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Solution Overview
Problem
The existing cell pouches for secondary batteries face challenges in achieving high electrolyte peel strength, which is crucial for ensuring the reliability and performance of these batteries.
Innovation Solution
A cell pouch design with a specific composition and structure, including an inner resin layer with a Propylene Ethylene Rubber (PER) content ratio of 10% or less and a PER length of 0.3 μm or more, along with sequential lamination of layers such as barrier, outer resin, surface treatment, and adhesive layers, to enhance electrolyte peeling strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the content ratio of PER in the inner resin layer is increased, then the chemical resistance properties are improved, but the electrolyte peel strength decreases
Solution Approach 1:
The patent changes the parameters of PER in the inner resin layer by limiting its content ratio to 10% or less and controlling its length to 0.3 μm or more. This parameter optimization resolves the contradiction by achieving the right balance between chemical resistance and electrolyte peel strength, preventing excessive PER from degrading adhesion while maintaining sufficient chemical resistance.
Solution Approach 2:
The patent uses a multi-layer composite structure consisting of an inner resin layer, barrier layer, and outer resin layer. The inner resin layer is specifically designed with controlled PER content and length, while other layers provide complementary functions. This composite approach allows each layer to optimize its properties without compromising the overall performance, resolving the trade-off between chemical resistance and peel strength.
2Reliability
If the PER length in the inner resin layer is increased, then the chemical resistance properties are improved, but the electrolyte peel strength decreases
Solution Approach 1:
The patent optimizes the PER length parameter by setting it to 0.3 μm or more, which is the critical threshold that balances chemical resistance and adhesion. This parameter control prevents PER from becoming too long and causing adhesion failure, while still providing sufficient chemical resistance properties.
3Strength
If a multi-layer structure with additional surface treatment and adhesive layers is added, then the electrolyte peel strength is improved, but the device complexity increases
Solution Approach 1:
The patent divides the pouch structure into distinct functional layers: inner resin layer, barrier layer, outer resin layer, surface treatment layers, and adhesive layers. Each layer performs a specific function, allowing the system to achieve high electrolyte peel strength through the coordinated action of multiple specialized components rather than a single complex material.
Solution Approach 2:
The patent introduces surface treatment layers and adhesive layers as intermediary components between the resin layers and the electrolyte/cells. These intermediary layers specifically address the adhesion problem without requiring fundamental changes to the base resin structure, thus improving peel strength while keeping the overall design manageable.
Data Source
AI summary
In a secondary battery, a cell pouch for a secondary battery according to the present invention comprises an inner resin layer, a barrier layer, and an outer resin layer, wherein the inner resin layer, the barrier layer, and the outer resin layer are sequentially laminated, wherein a content ratio of PER (Propylene Ethylene Rubber) in the inner resin layer is 10% or less. According to the present invention, the electrolyte peel strength of the secondary battery cell is improved to ensure excellence and reliability, as well as it is possible to use a cell pouch for a secondary battery with excellent conditions such as an electrolyte peeling strength of 1,000 (gf/15 mm) or more, due to the property, in which the electrolyte peel strength of the secondary battery cell is inversely proportional to the content ratio of PER in the inner resin layer and is proportional to the length of PER.