Battery Unit Cell Adhesive Composition for Uniform Electrode Lamination
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Solution Overview
Problem
The conventional method of manufacturing unit cells for lithium secondary batteries results in uneven adhesive forces between electrodes and separators, leading to potential damage and defects in the electrode assembly.
Innovation Solution
A unit cell manufacturing method involving the use of an adhesive composition comprising a copolymer and a rosin ester-based additive, with specific weight percentages and repeating units, applied to the surfaces of electrodes and separators to ensure uniform adhesion and minimize heat and pressure during lamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If heating and pressing are applied to laminate electrodes and separators, then adhesion between electrodes and separators is improved, but electrodes may be pushed off or damaged in their original positions
Solution Approach 1:
The patent applies adhesive composition to the separator surface before the lamination process. This preliminary application of adhesive ensures that when heating and pressing occur, the electrodes are already secured to the separator, preventing them from being pushed off or damaged. The adhesive is applied in advance to create a bonding layer that protects electrode positioning during the thermal compression process.
2Strength
If heating is performed during lamination, then adhesion between electrodes and separators is improved, but uneven heating may cause difference in adhesive force
Solution Approach 1:
The patent modifies the adhesive composition by incorporating specific additives and adjusting its chemical parameters to reduce sensitivity to heating conditions. The adhesive is formulated with compounds that maintain consistent bonding properties across varying temperature distributions, ensuring uniform adhesive force even when heating is not perfectly even throughout the lamination process.
3Strength
If heating and pressing are applied to laminate electrodes and separators, then adhesion is improved, but heat and pressure may cause deformation or damage to the electrode assembly
Solution Approach 1:
The patent introduces an adhesive composition as an intermediary material between the electrodes and separators. This adhesive layer acts as a buffer that distributes thermal and mechanical stresses more evenly, preventing direct transmission of excessive heat and pressure to the electrodes. The adhesive composition is specifically formulated to withstand lamination conditions while protecting the electrode assembly from deformation and damage.
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 composition prevents misalignment and deformation of electrodes and separators, reducing defects and ensuring consistent adhesive forces, thereby improving the manufacturing process and battery cell performance.
Implementation Method 1
an adhesive composition that can be used in the manufacture of an electrode assembly for a secondary battery... at least one surface of the electrode and the separator is applied with an adhesive to adhere the electrode and the separator
Data Source
AI summary
A unit cell includes a separator and an electrode, which are alternately laminated by a predetermined number. The unit cell is configured such that: the unit cell is laminated in the order of a lower separator, any one electrode of an anode or a cathode, an upper separator, and the other one electrode of the anode or the cathode, wherein at least one surface of the electrode and the separator is applied with an adhesive to adhere the electrode and the separator or the lower separator and the upper separator. The adhesive contains an adhesive composition comprising a copolymer and a rosin ester-based additive, the copolymer contains 60.1 to 79.9% by weight of two or more kinds of alkyl (meth)acrylate-based repeating units (A), and 20.1 to 39.9% by weight of (meth)acrylate-based repeating unit (B) having a hydroxyl group at its end.