Battery Electrode Insulating Layers for Burr-Protected Tabs
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Solution Overview
Problem
Existing battery technologies face challenges in improving the reliability of electrode pieces due to issues such as burrs and exposed end faces during cutting, which can lead to short circuits and reduced safety.
Innovation Solution
The electrode piece design includes a current collector with a specific arrangement of insulating layers, using a thermoplastic polymer and organic binder with a thermal decomposition temperature of ≥400°C, allowing the insulating layer to adhere to the current collector and coat burrs and exposed ends, reducing the risk of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the current collector is cut to form tabs, then the battery cell can be assembled, but burrs and exposed end faces are generated which reduce reliability
Solution Approach 1:
The insulating layer is coated on the current collector surface before the cutting process. This preliminary insulation ensures that when the tab is cut, any burrs generated are already covered with insulating material, and the exposed end face is protected. The cutting process creates burrs and exposes the end face, but since the insulating layer is already in place, these defects do not lead to short circuits.
Solution Approach 2:
The insulating layer acts as an intermediary substance between the conductive current collector and the potential short circuit path. It mediates the harmful effect of burrs and exposed end faces by providing an insulating barrier, preventing direct electrical contact between opposite polarity electrodes.
2Ease of manufacture
If a conventional insulating layer is used, then it can be applied to the current collector, but it detaches during cutting due to heat radiation
Solution Approach 1:
The organic binder's thermal decomposition temperature is changed to be ≥400°C, which is significantly higher than the temperature of heat radiation during cutting. This parameter change ensures the binder remains stable and maintains adhesion under the thermal conditions of the cutting process, preventing insulating layer detachment.
Solution Approach 2:
Instead of using expensive high-temperature ceramic coatings that are difficult to apply, the patent uses an organic binder-based insulating layer that can be applied through conventional coating methods. The binder is designed to be stable at cutting temperatures, providing a cost-effective solution that maintains adhesion without requiring complex application processes.
3Ease of manufacture
If the organic binder has low thermal decomposition temperature, then it can be easily processed, but it decomposes during cutting causing insulating layer detachment
Solution Approach 1:
The thermal decomposition temperature parameter of the organic binder is specifically changed to be ≥400°C. This parameter change allows the binder to withstand the heat radiation during cutting without decomposing, while still maintaining processability through conventional coating methods. The binder remains stable under cutting conditions, preventing insulating layer detachment.
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
This design enhances the reliability of battery cells by preventing insulating layer detachment and burr contact with opposite polarity electrodes, thereby improving safety and reducing the risk of short circuits.
Implementation Method 1
the thermoplastic polymer in the second insulating layer on the surface of the transition area changes from a solid state to a flowable state when heated, and the flowable thermoplastic polymer flows to the end face of the first end and solidifies at the end face after cooling
Implementation Method 2
the arrangement of the organic binder allows the thermoplastic polymer in the second insulating layer to adhere to the surface of the current collector
Implementation Method 3
by setting the thermal decomposition temperature T of the organic binder to be ≥400° C., the organic binder does not decompose during the cutting process
Data Source
AI summary
The electrode piece includes a current collector, an active substance layer, a first insulating layer and a second insulating layer, where the current collector includes a main body part and a tab, the tab extends from a first end of the main body part, the first end is an end of the main body part in a first direction, the main body part includes a coating area and a transition area, and the transition area is arranged between the coating area and the tab; the active substance layer is arranged on a surface of the coating area; the first insulating layer is arranged on an end face of the main body part at the first end; and at least a part of the second insulating layer is arranged on a surface of the transition area, the second insulating layer includes a thermoplastic polymer and an organic binder.