Lithium-Ion Cathode Interface for Overcharge Heat Reduction
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Solution Overview
Problem
High-capacity lithium ion batteries face safety issues due to excessive heat generation during overcharging, leading to potential thermal runaway and structural damage, which existing technologies have not adequately addressed.
Innovation Solution
The lithium ion battery design incorporates a positive electrode with an AlF3 protective layer, an adhesive in the positive active material layer, and FSI− ions in the electrolyte, optimizing the mass percentages and thicknesses to reduce reaction heat, internal resistance, and enhance thermal stability and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high-capacity lithium ion battery is used, then the battery capacity is improved, but the heat generation during overcharging increases leading to safety issues
Solution Approach 1:
The patent introduces FSI- ions as an intermediary substance in the electrolyte that mediates the interaction between the electrode and electrolyte during overcharging. These ions form a protective interface layer that prevents direct harmful reactions while allowing ion transport, thus reducing heat generation without compromising capacity
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by incorporating FSI- ions and adjusts the adhesive mass percentage in the positive active material layer. These parameter changes modify the thermal and electrochemical properties of the battery system, enabling high capacity operation with reduced heat generation and improved safety
2Power
If the battery temperature increases during overcharging, then the reaction rate is improved, but the SEI ruptures and thermal runaway occurs
Solution Approach 1:
The patent applies beforehand cushioning by pre-forming a stable protective layer on the positive electrode using the AlF3 layer and FSI- ions in the electrolyte. This protective layer acts as a cushion that absorbs and dissipates thermal energy before it can reach critical levels that would cause SEI rupture or thermal runaway
Solution Approach 2:
The patent uses composite materials by combining AlF3 with the positive active material layer, and FSI- ions with other electrolyte components. This composite structure provides both the reactivity needed for high power output and the thermal stability required to prevent SEI rupture and thermal runaway
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 configuration significantly reduces reaction heat and Joule heat, improves thermal stability, and prevents safety hazards, thereby enhancing the reliability and safety of the lithium ion battery while maintaining good electrical performance.
Implementation Method 1
an AlF3 protective layer located between the positive current collector and the positive active material layer... significantly reduces reaction heat and Joule heat, improves thermal stability
Implementation Method 2
The electrolyte includes FSI− ions... reduces internal resistance, and enhances the reliability and safety
Implementation Method 3
The positive active material layer includes a positive active material and an adhesive... improves thermal stability
Implementation Method 4
a large amount of Joule heat and reaction heat is generated during overcharging... significantly reduces reaction heat and Joule heat
Data Source
AI summary
Provided are a lithium ion battery and an energy storage device. The lithium ion battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. The separator is located between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive current collector and a positive active material layer covering the positive current collector. The positive active material layer includes a positive active material and an adhesive. A mass percentage of the adhesive in the positive active material layer is a. The electrolyte includes FSI− ions, and a mass percentage of the FSI− ions to all anions in the electrolyte is b. The positive electrode plate further includes an AlF3 protective layer located between the positive current collector and the positive active material layer. The AlF3 protective layer has a thickness of c micron, where a, b, and c satisfy 3%≤a+b*c≤34%.