Battery Electrode Insulating Layer Design for Burr Protection
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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, utilizing a thermoplastic polymer and an organic binder with a thermal decomposition temperature of ≥400°C, which adheres to the collector and forms a protective coating on burrs and exposed ends during cutting, reducing the risk of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the current collector is cut to form tabs, then the electrode piece can be connected to external circuits, but burrs and exposed end faces are generated which can cause short circuits and reduce safety
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, preventing them from causing short circuits between electrodes with opposite polarity.
Solution Approach 2:
The insulating layer acts as an intermediary substance between the conductive current collector and the potentially harmful burrs/exposed ends. This intermediate layer prevents direct contact between conductive elements that could cause short circuits, while still allowing the tab to perform its electrical connection function.
2Ease of manufacture
If the insulating layer uses conventional binders, then the coating can be applied easily, but the layer detaches during cutting due to thermal decomposition
Solution Approach 1:
The patent changes the thermal parameter of the binder by selecting an organic binder with a decomposition temperature of ≥400°C. This parameter change ensures the binder remains stable during the cutting process, maintaining the insulating layer's adhesion to the current collector when thermal stress is applied.
Solution Approach 2:
The insulating layer is formulated as a composite material containing thermoplastic polymer, organic binder, and optionally inorganic filler. This composite structure combines the adhesion benefits of thermoplastic polymers with the thermal stability of high-temperature organic binders, ensuring both easy application and maintained adhesion during cutting.
3Ease of manufacture
If the organic binder has low thermal decomposition temperature, then the coating process is simpler, but the binder decomposes during cutting causing insulating layer detachment
Solution Approach 1:
The patent raises the thermal decomposition temperature parameter of the organic binder to ≥400°C. This parameter change allows the coating process to remain simple while ensuring the binder does not decompose during the cutting operation, thereby maintaining the integrity and proper thickness of the insulating layer.
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 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
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AI summary
Embodiments of the present application provide an electrode piece, a preparation method therefor, a battery cell, a battery, and an electric apparatus, which belong to the technical field of batteries. 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, and the organic binder has a thermal decomposition temperature T≥400°C. The technical solution of the present application is useful for improving reliability of a battery cell.