Negative Electrode Protective Layer for Li-Ion Short-Circuit Mitigation
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Solution Overview
Problem
Lithium-ion batteries face safety risks due to internal short circuits and thermal runaway, particularly when the positive electrode plate comes into contact with the negative electrode plate, leading to potential fires or explosions, despite protective measures on the positive electrode plate not adequately addressing cross-sectional contacts and separator film damage.
Innovation Solution
A negative electrode plate with an additional layer comprising a negative electrode active substance, a protective substance including nanometal oxide and a conductive agent, and a bonding agent is applied to the surface of the negative electrode current collector, which reduces the risk of thermal runaway by preventing short circuits and maintaining fast charging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the separator film is strengthened to prevent damage under external force, then the protection against short circuit is improved, but the external force can still damage the separator film causing short circuit
Solution Approach 1:
The protective substance on the negative electrode plate serves as a beforehand cushioning measure. When external force causes the positive electrode plate to contact the negative electrode plate, the protective substance layer absorbs and distributes the stress, preventing direct damage to the separator film and reducing the risk of short circuit.
2Reliability
If protective measures are added to prevent short circuit, then safety is improved, but the charging/discharging speed may be affected
Solution Approach 1:
The protective substance is formulated as a composite material containing nanometal oxide particles and conductive agent. The nanometal oxide provides protective barrier function, while the conductive agent maintains electrical conductivity, ensuring that the protective layer does not significantly increase resistance and affect charging/discharging speed.
Solution Approach 2:
The protective layer is designed with controlled thickness and composition to balance protection and conductivity. By adjusting the particle size of nanometal oxide and the content of conductive agent, the layer provides adequate protection while maintaining sufficient ion and electron transport for fast charging performance.
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 reduces the risk of thermal runaway and improves safety by preventing severe short circuits between the positive and negative electrode plates, while maintaining the lithium-ion battery's electrochemical performance and energy density.
Implementation Method 1
The protective substance includes a nanometal oxide and a conductive agent... When the lithium-ion battery is damaged, the protective substance can reduce a risk of thermal runaway caused by a short circuit between a positive electrode current collector of a positive electrode plate and the negative electrode active substance
Implementation Method 2
Because both the lithium titanate and the carbon-coated lithium titanate have a high lithium intercalation potential (1.55 V vs. Li+/Li), no metal lithium dendrite is generated regardless of a rate at which charging and discharging are performed
Implementation Method 3
The protective substance includes a nanometal oxide and a conductive agent... does not affect fast charging performance of the battery
Data Source
AI summary
A negative electrode plate of a lithium-ion battery, a lithium-ion battery, and an electronic device are provided. The negative electrode plate of the lithium-ion battery includes a negative electrode current collector and an additional layer. The additional layer is disposed on a surface of the negative electrode current collector. The additional layer includes a negative electrode active substance, a protective substance, and a bonding agent. The negative electrode active substance includes at least one of a carbon material, an alloyed material, and a silicon material, the protective substance includes a nanometal oxide and a conductive agent, and the protective substance further includes lithium titanate or carbon-coated lithium titanate. When the lithium-ion battery is damaged, the protective substance can reduce a risk of thermal runaway caused by a short circuit between a positive electrode current collector of a positive electrode plate and the negative electrode active substance.