Secondary Battery Copolymer Binder for Stable Electrode Adhesion
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Solution Overview
Problem
The bonding force between the electrode current collector and the active material layer in secondary batteries decreases over cycles, affecting the cycle life of the battery.
Innovation Solution
A copolymer comprising specific monomer units is used as a binder to enhance the bonding force between the electrode components, improving electrochemical performance by balancing strength, flexibility, and slurry stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a conventional binder is used in the electrode plate, then the initial bonding force between the current collector and active material layer is sufficient, but the bonding force decreases over cycles, affecting cycle life
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by using a copolymer with specific monomer units (acrylic acid, acrylic ester, and vinylene carbonate) in controlled molar ratios. This chemical parameter change enables the binder to maintain stable bonding force over cycles while accommodating active material expansion, thereby resolving the contradiction between initial bonding strength and long-term durability
Solution Approach 2:
The patent creates a composite binder system by combining multiple monomer units (acrylic acid, acrylic ester, and vinylene carbonate) into a copolymer structure. This composite material approach allows the binder to simultaneously provide strong initial adhesion and flexible expansion accommodation, resolving the contradiction between bonding strength and cycle stability
2Reliability
If the active material layer expands during cycling, then the electrochemical activity is maintained, but the bonding force between the current collector and active material layer decreases
Solution Approach 1:
The patent introduces dynamic flexibility into the binder through the vinylene carbonate monomer unit, which allows the binder matrix to dynamically adjust and expand with the active material during cycling. This dynamic adaptation maintains bonding force while accommodating volume changes, resolving the contradiction between electrochemical performance and bonding stability
Solution Approach 2:
The patent modifies the physical and chemical parameters of the binder by incorporating vinylene carbonate units that provide elastic deformation capability. This parameter change enables the binder to undergo reversible expansion and contraction, maintaining reliable bonding despite active material volume changes during electrochemical cycling
Data Source
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AI summary
The present application discloses a secondary battery, a method for preparing the same, a copolymer and an apparatus. The secondary battery includes a binder for binding a first substance and a second substance, the binder including a copolymer, wherein the copolymer comprises at least a first monomer unit represented by formula (I), a second monomer unit represented by formula (II), and a third monomer unit represented by formula (III): The secondary battery provided by the present application can effectively increase the boding force between the first substance and the second substance by including a specific binder, thereby improving the electrochemical performance of the secondary battery.