Inorganic Coated Electrode Assembly for Secondary Battery Short Circuit Prevention
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Solution Overview
Problem
Secondary batteries face issues with burrs on cut surfaces of electrodes and low thermal stability of separators, leading to potential short circuits and explosions, which existing technologies have not adequately addressed.
Innovation Solution
The application of an inorganic coating layer, made from a slurry containing ceramic powder such as alumina or zirconia, is applied to the edges and surfaces of both positive and negative plates to prevent burrs and enhance thermal stability, while also covering active material areas to prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous separator made of polyethylene or polypropylene is used to prevent short circuits, then the separator can prevent direct contact between electrodes, but the separator has low thermal stability and may be fractured or melted during thermal runaway
Solution Approach 1:
The patent applies a composite structure by coating the porous separator with an inorganic layer (alumina, zirconia, or silica). This composite structure combines the porous structure for ion permeability with the inorganic layer for thermal stability, allowing the separator to maintain both short circuit prevention and high temperature resistance.
Solution Approach 2:
The patent changes the thermal parameter of the separator by applying an inorganic coating layer that raises the decomposition temperature from the original polyethylene/polypropylene range to above 1000°C, fundamentally improving the thermal stability while maintaining the separator's primary function.
2Manufacturing precision
If electrodes are cut during manufacturing, then the electrodes can be formed to specification, but burrs are formed on the cut surfaces which can cause short circuits and explosions
Solution Approach 1:
The patent introduces an inorganic coating layer as an intermediary substance on the electrode surfaces. This coating layer acts as a protective barrier that prevents burr formation during cutting and also prevents any existing burrs from causing short circuits, effectively mediating between the cutting process and the electrode functionality.
Solution Approach 2:
The inorganic coating layer is applied beforehand to the electrode surfaces before cutting. This preliminary protective action prevents burr formation during the subsequent cutting process and neutralizes the harmful effects of burrs before they can cause short circuits or explosions.
3Ease of operation
If the separator is made of porous materials for ion permeability, then the separator allows ion transport, but the porous structure lacks thermal stability and can fracture or melt
Solution Approach 1:
The patent creates a composite separator structure where the porous base material (polyethylene or polypropylene) provides ion permeability while the inorganic coating layer (alumina, zirconia, or silica) provides thermal stability. This composite approach allows both functions to coexist without compromising either property.
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 solution significantly reduces the likelihood of short circuits and explosions, improves battery reliability, and minimizes defective battery production, thereby reducing manufacturing costs.
Implementation Method 1
an inorganic coating layer, made from a slurry containing ceramic powder such as alumina or zirconia, is applied to the edges and surfaces of both positive and negative plates
Implementation Method 2
the porous structure of the separator may be fractured or melted due to a low thermal stability of the porous materials
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An electrode assembly includes a positive plate, a negative plate, and a separator located between the positive plate and the negative plate, each of the positive plate and the negative plate having an active part formed by applying an active material to at least one surface and a non-applied part from which the active material is omitted, wherein a side part extending from at least one of the active part of the positive plate and the active part of the negative plate is coated with an inorganic coating layer.