Battery Electrode Adhesive Coating to Prevent Separator Bending
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Solution Overview
Problem
Lithium secondary batteries face issues with separator bending and potential internal short circuits during manufacturing and high-temperature exposure, which can lead to safety risks due to inadequate adhesion between electrodes and separators.
Innovation Solution
An electrode with an adhesive coating portion is integrated into the lithium secondary battery, specifically applied to the electrode tab and electrode mixture layer, using a non-electric conductive adhesive with a glass transition temperature of 100° C or lower, to enhance adhesion and prevent separator bending and shrinkage, thereby ensuring insulation between positive and negative electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive tape is used to connect electrode and separator, then adhesion is improved, but separator bending and short circuit occur at high temperature due to adhesive melting
Solution Approach 1:
The invention changes the thermal parameter of the adhesive by selecting materials with glass transition temperatures of 100°C or lower, ensuring the adhesive remains flexible and effective at battery operating temperatures without melting or losing adhesion properties
Solution Approach 2:
The invention uses composite adhesive materials comprising polymer matrices (such as polyacrylonitrile, polyacrylic acid, or carboxymethyl cellulose) combined with specific additives to achieve both strong adhesion and thermal stability, creating a multi-component system that addresses both bonding strength and temperature resistance
2Ease of manufacture
If separator is not fixed to electrode, then manufacturing simplicity is maintained, but separator bends and rolls during transfer and stacking
Solution Approach 1:
The adhesive coating is applied to the electrode surface before assembly, pre-establishing the bonding capability that prevents separator bending during subsequent manufacturing steps like transfer and stacking, eliminating the need for additional fixing mechanisms
Solution Approach 2:
The adhesive coating acts as an intermediary substance between the electrode and separator, providing a bonding interface that maintains separator flatness without requiring mechanical clamps, tapes, or other complex fixing structures
3Strength
If adhesive coating is applied to entire electrode surface, then adhesion is maximized, but manufacturing complexity and cost increase
Solution Approach 1:
The adhesive coating is applied selectively to specific regions of the electrode where separator contact is required, rather than the entire surface, optimizing adhesion where needed while reducing material cost and application process complexity
Solution Approach 2:
The invention applies adhesive coating to slightly more than the minimum required area (excessive action), ensuring complete coverage of separator contact zones with a margin of safety, while still avoiding the complexity of precise full-surface application
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 coating portion effectively secures the separator to the electrode, preventing bending and contact between electrodes, thus enhancing the safety and reliability of lithium secondary batteries by maintaining insulation even at high temperatures.
Implementation Method 1
an adhesive coating portion is added to an upper surface of an electrode tab and at least a part of an upper surface of the electrode mixture layer
Implementation Method 2
using a non-electric conductive adhesive with a glass transition temperature of 100° C or lower
Implementation Method 3
a glass transition temperature of 100° C or lower
Data Source
AI summary
An electrode for a lithium secondary battery may include an electrode mixture layer and an electrode current collector. The electrode mixture layer may be disposed on at least one of a first surface and a second surface of the electrode current collector. The electrode current collector may include an electrode tab extending from an outer periphery of the electrode mixture layer as a portion other than a portion at which the electrode mixture layer is formed. An adhesive coating portion may be disposed at at least a portion of an upper surface of the electrode tab, at at least a portion of an upper surface of the electrode mixture layer, or at both of the foregoing. The electrode may be coupled to a separator via the adhesive coating portion.