Lithium Battery Anode Dendrite Control for Low-Temperature Transfer
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Solution Overview
Problem
High-voltage rechargeable lithium batteries face challenges in maintaining structural integrity of the positive electrode, leading to increased resistance and decreased low-temperature performance, which affects the battery's capacity and safety.
Innovation Solution
The formation of small-sized lithium dendrites on the negative electrode surface, with an average size of 5 μm or less, is achieved through specific charge and discharge cycles at controlled temperatures, enhancing lithium ion transfer and low-temperature characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If doping is performed to strengthen the internal structure of the positive active material, then the structural integrity of the positive electrode is improved, but the resistance of the positive active material increases
Solution Approach 1:
The patent changes the physical-chemical parameters of the positive active material by controlling the doping concentration and type, as well as the heat treatment temperature and time. This optimization balances the structural strengthening effect with the resistance increase, achieving improved structural integrity while minimizing resistance changes.
Solution Approach 2:
The patent creates a composite structure by doping the positive active material with specific elements, forming a multi-component system where the dopant elements reinforce the crystal structure while maintaining or improving electrical properties. This composite approach resolves the contradiction between strength and resistance.
2Stability of the object's composition
If a coating layer is formed to strengthen the surface of the positive active material, then the structural stability is improved, but the resistance increases
Solution Approach 1:
The patent optimizes the coating layer parameters including thickness, composition, and deposition conditions. By precisely controlling these parameters, the coating provides structural stabilization while maintaining low resistance through optimized thickness and material selection.
Solution Approach 2:
The patent applies different coating materials and thicknesses to different regions or aspects of the positive active material surface, creating local variations that provide structural support where needed while maintaining high conductivity in other areas. This localized approach resolves the contradiction between stability and resistance.
3Quantity of substance
If the battery operates at high voltage to increase capacity, then the energy density is improved, but the structural collapse of the positive electrode occurs
Solution Approach 1:
The patent performs preliminary doping and coating treatments on the positive active material before battery assembly and operation. This pre-strengthening of the crystal structure allows the material to withstand the high voltage stress during subsequent high-capacity operation, preventing structural collapse while maintaining high energy density.
Solution Approach 2:
The patent introduces protective doping elements and coating layers that act as a cushion or buffer against the mechanical stress and structural degradation that occurs during high-voltage operation. This beforehand protection enables the battery to operate at high voltage without suffering from structural collapse.
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 approach improves the low-temperature performance and safety of lithium batteries by reducing interface resistance and maintaining battery performance, while preventing excessive lithium deposition that can lead to battery failure.
Implementation Method 1
enhancing lithium ion transfer and low-temperature characteristics
Data Source
AI summary
A rechargeable lithium battery includes a negative electrode comprising a current collector, a negative active material layer on the current collector, and lithium dendrites on a surface of the negative active material layer and having an average size (e.g., an average length) of about 5 μm or less and a rod-like shape; a positive electrode; and a non-aqueous electrolyte.