Core-Shell Copper Composite for Battery Overcharge Protection
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Solution Overview
Problem
Lithium-ion batteries face safety hazards due to overcharging, which can lead to battery failure, fire, or explosion, as they use flammable organic solvents and have limitations with existing additives for preventing overcharge, such as cathode passivation and redox shuttle additives that deteriorate electrical performance.
Innovation Solution
A composite material with a core-shell structure is developed, where the core is made of metallic copper or copper-containing compounds and the shell is made of silicon dioxide or titanium dioxide, allowing copper ions to form dendrites that pierce the separator and create a local short circuit, reducing voltage and heat accumulation during overcharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cathode passivation additives are added to the electrolyte to prevent overcharging, then battery safety is improved, but electrical performance deteriorates
Solution Approach 1:
The patent introduces a mediator substance (copper-containing compound with specific particle size and surface treatment) that acts as an intermediate between the electrode and electrolyte. This mediator enables overcharge protection through copper dendrite formation while minimizing direct interaction between traditional additives and the electrode, thereby preserving electrical performance while improving safety
Solution Approach 2:
The patent changes critical parameters of the copper-containing compound including particle size (0.01-5 μm), surface treatment (hydrophobic or hydrophilic), and chemical composition to optimize both safety and electrical performance. By precisely controlling these parameters, the system achieves overcharge protection without significant deterioration of charge-discharge characteristics
2Reliability
If redox shuttle additives are added to the electrolyte to consume overload current, then battery safety is improved, but oxidation potential is low and current consumption is insufficient
Solution Approach 1:
The patent implements preliminary action by pre-positioning copper-containing compounds on the electrode surface before overcharge occurs. When overcharging happens, copper ions are immediately available to form dendrites and shut off current, eliminating the delay inherent in redox shuttle mechanisms and providing rapid, effective current consumption with higher power capability
Solution Approach 2:
The patent converts the potentially harmful effect of copper dendrites (which can cause short circuits) into a beneficial safety mechanism. By controlling dendrite formation through specific copper compound parameters, the harmful short-circuiting effect is transformed into a controlled current-shutting mechanism that protects the battery while maintaining high current consumption capability
3Reliability
If copper ions form dendrites to create local short circuit for overcharge protection, then overcharge resistance is improved, but internal short circuit risk increases
Solution Approach 1:
The patent applies local quality by creating localized copper dendrite formation only at specific sites on the electrode surface where copper-containing compounds are positioned. This localized approach ensures dendrites form only where needed for overcharge protection, minimizing the risk of widespread internal short circuits while maintaining effective overcharge resistance
Solution Approach 2:
The patent implements beforehand cushioning by pre-treating the electrode surface with hydrophobic or hydrophilic agents and positioning copper-containing compounds in advance. This preparation creates a controlled environment that guides dendrite formation to safe locations and prevents uncontrolled short circuits, cushioning against the potential harmful effects before they can occur
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 composite material effectively enhances the safety of lithium-ion batteries by preventing thermal failure and maintaining normal electrical performance, ensuring excellent overcharge resistance without compromising energy density.
Implementation Method 1
Under the action of the electric field force inside the battery, the copper ion will migrate to the surface of the negative electrode and be reduced to form copper dendrites
Implementation Method 2
the copper ion will migrate to the surface of the negative electrode and be reduced to form copper dendrites
Implementation Method 3
The copper dendrites gradually grow on the surface of the negative electrode and pierce the separator, causing a local internal short circuit inside the battery
Implementation Method 4
the core material will react with the hydrofluoric acid generated by the electrolyte to generate copper ions
Data Source
AI summary
The present application relates to a composite material with a core-shell structure for battery, wherein the core is made of a core material including metallic copper or a copper-containing compound; the shell is made of a shell material including at least one of silicon dioxide and titanium dioxide; and the core material has an average particle size D50 of 0.01 μm-5 μm, optionally 0.1 μm-3 μm, and more optionally 0.1 μm-2 μm. The present application also relates to secondary battery containing the composite material, a battery module, a battery pack, and an apparatus.