Negative Electrode Coating for Internal Short Detection in Li Batteries
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Solution Overview
Problem
Lithium secondary batteries face safety issues due to internal shorts, which can lead to heat generation, meltdown, and explosion, necessitating effective safety measures to prevent thermal runaway.
Innovation Solution
A negative electrode for lithium secondary batteries is designed with a coating layer containing silicon-containing particles, aluminum-containing particles, and a dispersant, achieving a specific volume resistance that provides appropriate insulation and allows a predetermined current to leak in the event of an internal short.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a coating layer with high insulation is applied to prevent internal short, then safety is improved, but the ability to detect internal short through current leakage is reduced
Solution Approach 1:
The coating layer's volume resistance is precisely controlled within a specific range (1.0×10^-4 to 1.0 Ω·cm) rather than maximizing insulation. This parameter optimization allows the layer to provide sufficient insulation to prevent meltdown while maintaining enough conductivity to enable current leakage for detection purposes.
Solution Approach 2:
The coating layer is applied selectively only on the negative electrode active layer where internal shorts are most likely to occur, rather than uniformly across all battery components. This localized approach provides targeted safety and detection capability at the critical interface between electrodes.
2Reliability
If a coating layer is added to provide insulation and safety, then safety is improved, but device complexity increases
Solution Approach 1:
The coating layer is formulated as a composite material containing silicon-containing particles, aluminum-containing particles, and dispersant. This composite structure provides the desired electrical properties (controlled volume resistance) and safety functions while maintaining a relatively simple single-layer configuration on the electrode.
Solution Approach 2:
The coating layer performs multiple functions simultaneously: it provides electrical insulation to prevent thermal runaway, enables current leakage for internal short detection, and maintains electrode structural integrity. This multi-functionality reduces the need for additional separate safety components.
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 prevents melt-down and rapid heat generation in lithium secondary batteries during internal shorts, allowing for quick detection and preemptive control to avoid thermal runaway, thereby enhancing safety.
Implementation Method 1
a volume resistance of the coating layer is about 1.0×10−4 Ω·cm to 1.0 Ω·cm
Data Source
AI summary
A negative electrode for a lithium secondary battery includes: a negative electrode active layer provided on at least one surface of a negative electrode current collector, and including a negative electrode active material; and a coating layer disposed on the negative electrode active layer. The coating layer contains silicon-containing particles, aluminum-containing particles and a dispersant, and a volume resistance of the coating layer is about 1.0×10−4 Ω·cm to 1.0 Ω·cm.