Secondary Battery Adhesive Layer for Electrode Restraint Stability
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Solution Overview
Problem
The clearance between the electrode assembly and the packaging housing in secondary batteries, such as lithium-ion batteries, leads to relative movement, damaging the adhesive interface and causing safety issues like voltage failure and short circuits due to the poor restraining effect of common adhesive tapes like poly(styrene-b-isoprene-b-styrene) during drops.
Innovation Solution
A secondary battery design with an adhesive member comprising a first adhesive layer bonded to the housing and a second adhesive layer bonded to the electrode assembly, using poly(styrene-b-isoprene-b-styrene) and a first resin like poly(acrylonitrile-co-butadiene-co-styrene), polyurethane, or polystyrene, which swells in the electrolyte solution to increase friction and reduce stress, thereby improving bonding stability and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common adhesive tapes like poly(styrene-b-isoprene-b-styrene) are used to fix the electrode assembly, then the adhesive member provides insulation protection and fixation, but the bonding interface is prone to damage during drops, resulting in voltage failure and short circuits
Solution Approach 1:
The adhesive member is constructed as a composite structure with a substrate layer (PET or PI) providing mechanical strength and dimensional stability, combined with adhesive layers that provide bonding functionality. This composite structure prevents interface damage during drops while maintaining reliable fixation of the electrode assembly.
Solution Approach 2:
The patent modifies the adhesive composition by incorporating specific resin components (polyurethane, polyacrylic acid, or carboxymethyl cellulose) in controlled amounts (5-50 parts by weight per 100 parts adhesive resin) to optimize the balance between bonding strength and interface stability, reducing the risk of voltage failure and short circuits.
2Reliability
If the adhesive member uses high friction coefficient materials to reduce stress at edges, then the probability of damage to bonding interface is reduced, but the device complexity increases due to multiple adhesive layers and material composition
Solution Approach 1:
The adhesive member is divided into functional segments: a substrate layer providing structural support and adhesive layers providing bonding functionality. This segmentation allows each layer to be optimized for its specific function while working together to reduce edge stress and prevent interface damage.
Solution Approach 2:
The substrate layer acts as an intermediary between the adhesive layers and the electrode assembly, distributing stresses and preventing direct transmission of impact forces to the bonding interface, thereby reducing the probability of damage while maintaining a relatively simple overall structure.
3Object-affected harmful factors
If the adhesive member defers relative movement between electrode assembly and housing, then the risk of bursting top seal and leaking electrolyte solution is reduced, but the manufacturing precision requirements increase to ensure proper bonding
Solution Approach 1:
The adhesive member uses flexible adhesive layers that can accommodate minor positioning variations during assembly while still providing effective restraint against relative movement. This flexibility reduces the risk of electrolyte leakage without requiring extremely high manufacturing precision for bonding position.
Solution Approach 2:
The adhesive member is designed with sufficient bonding area and appropriate adhesive composition to create a cushioning effect that prevents excessive relative movement before it can cause seal bursting or electrolyte leakage, providing a margin of safety against manufacturing variations.
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 design enhances the safety performance by reducing the risk of interface damage, electrolyte leakage, and battery bursting, while maintaining energy density and extending the service life of the battery.
Implementation Method 1
The first resin includes at least one of poly(acrylonitrile-co-butadiene-co-styrene), polyurethane, or polystyrene. In the secondary battery provided in this application, the first adhesive layer includes the above substances, thereby increasing a friction coefficient between the first adhesive layer and the inner surface of the housing.
Data Source
AI summary
An secondary battery includes an electrode assembly, an electrolyte solution, a housing, and an adhesive member. The adhesive member is disposed between the electrode assembly and the housing. The adhesive member includes a first adhesive layer and a second adhesive layer stacked up. The first adhesive layer is bonded to an inner surface of the housing. The second adhesive layer is bonded to an outer surface of the electrode assembly. The first adhesive layer includes poly(styrene-b-isoprene-b-styrene) and a first resin. The first resin includes at least one of poly(acrylonitrile-co-butadiene-co-styrene), polyurethane, or polystyrene. The secondary battery provided in this application includes an adhesive member, thereby reducing the probability of tearing of an outer surface of the electrode assembly and the risk of bursting a top seal of the secondary battery and leaking an electrolyte solution, and improving the safety performance of the secondary battery.