Laminated Battery Cell Separator With Adhesive Edge Confinement
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Solution Overview
Problem
Laminated battery cells, particularly those with lithium metal negative electrodes, are prone to short circuits due to the generation of 'dead lithium' and 'powdered lithium' during charging and discharging, which can lead to safety hazards such as fire or explosion.
Innovation Solution
A laminated battery cell design that includes a separator with an adhesive film layer on its side edges to form an accommodating region for the negative electrode sheet, confining 'dead lithium' and 'powdered lithium' within this region, thereby reducing the likelihood of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a laminated battery cell uses a conventional separator without adhesive film layer, then the manufacturing process is simpler and device complexity is reduced, but the negative electrode sheet cannot be effectively confined and dead lithium or powdered lithium can escape to cause short circuits
Solution Approach 1:
An adhesive film layer is introduced as an intermediary component between the separator body and the negative electrode sheet. This adhesive film layer serves as a mediator that provides both confinement function and adhesion, enabling the separator to effectively restrict the negative electrode sheet and prevent dead lithium or powdered lithium from escaping, thereby improving safety without requiring complex external structures.
Solution Approach 2:
The adhesive film layer is combined with the separator body to form an integrated separator structure. The adhesive film layer and separator body work together as a unified component, where the separator body provides the basic separation function and the adhesive film layer provides the confinement and adhesion function, achieving multiple functions through merging rather than separate components.
2Reliability
If the adhesive film layer width is increased to better confine the negative electrode sheet, then the confining effect is improved, but the adhesive film layer may overflow onto the main body of the negative electrode sheet after hot pressing causing adverse effects
Solution Approach 1:
The width of the adhesive film layer is precisely controlled within a specific parameter range (0.5mm to 2.0mm) to optimize the balance between confinement effect and overflow prevention. By adjusting this critical dimension parameter, the adhesive film layer can effectively confine the negative electrode sheet during normal operation while preventing excessive overflow onto the electrode sheet main body during hot pressing, thus eliminating harmful effects.
3Object-affected harmful factors
If the adhesive film layer width is decreased to prevent overflow onto the negative electrode sheet, then the harmful effects are reduced, but the confining effect on dead lithium and powdered lithium is weakened
Solution Approach 1:
The width of the adhesive film layer is precisely controlled within a specific parameter range (0.5mm to 2.0mm) to optimize the balance between confinement effect and overflow prevention. By adjusting this critical dimension parameter, the adhesive film layer can effectively confine the negative electrode sheet during normal operation while preventing excessive overflow onto the electrode sheet main body during hot pressing, thus eliminating harmful effects.
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 effectively immobilizes 'dead lithium' and 'powdered lithium', enhancing the safety of the battery by minimizing direct contact with the positive electrode sheet and reducing the risk of short circuits.
Implementation Method 1
an adhesive film layer is disposed on at least part of the side edge; the adhesive film layer is disposed along a first direction and/or a second direction of a plane where the separator body is located to form an accommodating region, and the negative electrode sheet is located in the accommodating region
Data Source
AI summary
The present application belongs to the technical field of batteries, and in particular, relates to a laminated battery cell, a secondary battery, and an electric device. The laminated battery cell provided by the present application includes a positive electrode sheet, a negative electrode sheet, and a separator. The separator includes a separator body. The separator body includes a side surface facing the negative electrode sheet. The side surface has a side edge, and an adhesive film layer is disposed on at least part of the side edge. The adhesive film layer is disposed along a first direction and/or a second direction of a plane where the separator body is located to form an accommodating region. The negative electrode sheet is located in the accommodating region.