Electrode Assembly Protective Layer for Short-Circuit Resistance
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Solution Overview
Problem
Batteries are prone to short circuits and thermal runaway when subjected to mechanical abuse, particularly between the positive electrode current collector and the negative electrode active material layer, posing a safety hazard.
Innovation Solution
An electrode assembly is designed with a positive electrode piece that includes a positive electrode current collector and functional layers, where the functional layers consist of a protective layer and a positive electrode active material layer, and the protective layer includes a conductive material and a binder, ensuring complete coverage of the current collector surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electrode structure without protective layer is used, then the device complexity is low and manufacturing is simple, but the reliability deteriorates due to easy occurrence of short circuit between positive electrode current collector and negative electrode active material layer under mechanical abuse
Solution Approach 1:
The protective layer is pre-formed on the positive electrode current collector before assembly, creating a preliminary protective barrier that prevents short circuits between the positive current collector and negative active material layer during mechanical abuse such as needle puncture or extrusion
Solution Approach 2:
The protective layer acts as an intermediary barrier between the positive electrode current collector and the negative electrode active material layer, preventing direct contact and short circuit while allowing the electrochemical functions to proceed normally
2Reliability
If the functional layer length is less than the current collector length, then the manufacturing precision requirement is reduced, but the reliability deteriorates due to non-coated foil zones that can cause short circuits
Solution Approach 1:
The functional layer is designed to cover specific critical areas of the positive electrode current collector with different lengths on different sides, providing targeted protection where short circuits are most likely to occur while optimizing manufacturing feasibility
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 solution effectively eliminates non-coated foil zones on the positive electrode current collector, reduces the risk of short circuits, and enhances the safety and cycle performance of the battery by ensuring comprehensive coverage and conductivity.
Implementation Method 1
the protection layer includes a conductive material and a binder
Data Source
AI summary
Provided are an electrode assembly and a battery. The electrode assembly includes a positive electrode piece formed by winding, including a positive electrode current collector and a functional layer, where the positive electrode current collector includes a first surface and a second surface which are parallel and opposite to each other, and the first and second surfaces of the positive electrode current collector are each provided with a functional layer; a length of the functional layer is the same as that of the positive electrode current collector; the functional layer includes a positive electrode active material layer, and a protective layer which is arranged between the positive electrode current collector and the positive electrode active material layer, and a length of the protective layer is smaller than or equal to that of the positive electrode active material layer; the protective layer includes a conductive material and a binder.