Positive-Electrode Plate Coating for Low-Gas High-Nickel Li-Ion Cells
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Solution Overview
Problem
Lithium nickel-cobalt-manganese ternary materials in lithium-ion batteries face issues with high nickel content causing oxidizing properties, structural changes, and gas generation due to residual lithium, leading to poor electrochemical performance and storage life, especially at high temperatures.
Innovation Solution
A positive-electrode plate with an inorganic dielectric layer containing no binder is used, which stabilizes the active substance, reduces side reactions, and controls internal resistance below 8 ohms, enhancing mechanical strength and preventing gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nickel content is used in lithium nickel-cobalt-manganese ternary material to increase specific capacity, then theoretical specific capacity is improved, but oxidizing property increases causing electrolyte degradation and gas generation
Solution Approach 1:
An inorganic dielectric layer is introduced as an intermediary between the high-nickel positive electrode active substance and the electrolyte. This intermediate layer prevents direct contact and chemical reactions between the oxidizing electrode material and the electrolyte, thereby suppressing gas generation and electrolyte degradation while maintaining the high specific capacity benefits of high-nickel content
2Quantity of substance
If high nickel content is used in lithium nickel-cobalt-manganese ternary material to increase specific capacity, then theoretical specific capacity is improved, but structural stability deteriorates causing release of transition metals
Solution Approach 1:
The patent creates a composite structure consisting of the lithium nickel-cobalt-manganese ternary material combined with an inorganic dielectric layer. This composite material approach allows the high-nickel content material to provide high specific capacity while the inorganic dielectric component provides structural stability and prevents transition metal release through its protective coating
3Quantity of substance
If residual lithium exists on the surface of positive-electrode active substance to compensate for lithium loss, then lithium loss in sintering process is compensated, but gas generation increases due to formation of LiOH and Li2CO3
Solution Approach 1:
The inorganic dielectric layer serves as a protective intermediary that prevents residual lithium on the electrode surface from reacting with atmospheric CO2 and H2O. By blocking this interaction, the layer prevents the formation of gas-generating compounds like LiOH and Li2CO3, thereby reducing gas generation in the battery while allowing necessary lithium content to be maintained
4Reliability
If inorganic dielectric layer is added to the positive-electrode plate to suppress gas generation and improve stability, then cycle life and storage life are extended, but internal resistance increases
Solution Approach 1:
The patent optimizes parameters of the inorganic dielectric layer including its thickness, composition, and physical properties to achieve a balance between protection and conductivity. By carefully controlling these parameters, the layer provides sufficient protection to extend cycle life and storage life while maintaining internal resistance at acceptable levels through precise parameter optimization
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 results in reduced gas generation, extended cycle and storage life, and improved stability and safety of lithium-ion batteries by preventing structural changes and side reactions, while maintaining low internal resistance.
Implementation Method 1
An inorganic dielectric layer containing no binder is disposed on a surface of the at least one positive-electrode active substance layer that is away from the current collector
Implementation Method 2
the high content of the nickel metal may also cause a structural change of the lithium nickel-cobalt-manganese ternary material, cause release of transition metals such as nickel and cobalt due to a reduction reaction of the metals
Implementation Method 3
a resistance R of the positive-electrode plate is not higher than 8 ohms
Data Source
AI summary
This application discloses a positive-electrode plate, a lithium-ion battery equipped with the positive-electrode plate, a battery module, a battery pack, and an apparatus. The lithium-ion battery includes a positive-electrode plate, a negative-electrode plate, a separator, and an electrolyte. The positive-electrode plate includes a positive-electrode current collector and a positive-electrode active substance layer that is disposed on a surface of the positive-electrode current collector and that includes a positive-electrode active substance. An inorganic dielectric layer containing no binder is disposed on a surface of the positive-electrode active substance layer, and a resistance of the positive-electrode plate is not higher than 8 ohms.