Lithium-ion battery, battery module, battery pack, and electrical device
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Solution Overview
Problem
Lithium-ion batteries face safety issues due to lithium plating on the convex surface of the negative electrode, leading to internal short circuits, which can cause fires and explosions, especially in jelly-roll structures.
Innovation Solution
A lithium-ion battery design with a specific electrolytic solution containing a first lithium salt LixR1(SO2N)xSO2R2 and a positive current collector with a support layer and metallic conductive layer, where the corner safety coefficient α, lithium salt content w, and conductive layer thickness β1 are optimized to suppress lithium plating and enhance safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a jelly-roll structure is used to increase energy density, then the battery capacity is improved, but lithium plating occurs on the convex surface of the negative electrode leading to internal short circuits
Solution Approach 1:
The patent applies local quality by placing a protective coating specifically on the convex surface of the negative electrode where lithium plating occurs most severely. This localized protection addresses the specific problem area without modifying the entire electrode structure, maintaining energy density while preventing short circuits at the critical convex regions.
Solution Approach 2:
The patent introduces an intermediary protective layer between the negative electrode and the electrolyte. This coating acts as a mediator that prevents direct contact and lithium plating while allowing ionic transport, thus resolving the contradiction between maintaining high capacity and preventing safety issues.
2Quantity of substance
If the positive electrode plate contacts the negative electrode plate under abnormal conditions, then internal short circuits occur causing temperature surge, but increasing electrode density improves energy storage
Solution Approach 1:
The patent introduces a protective coating as an intermediary layer between the positive and negative electrodes. This coating prevents direct contact under abnormal conditions while maintaining close proximity for efficient ionic transport during normal operation, thus preventing thermal runaway without sacrificing energy storage density.
Solution Approach 2:
The protective coating serves as beforehand cushioning by pre-establishing a protective barrier that prevents catastrophic short circuits before they can occur. This proactive protection allows the battery to maintain high electrode density while being protected against abnormal contact scenarios.
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 optimized design effectively reduces the risk of internal short circuits and improves the safety of lithium-ion batteries by preventing lithium plating at the convex surface, enhancing safety under abnormal conditions.
Implementation Method 1
The electrolytic solution contains a first lithium salt LixR1(SO2N)xSO2R2
Implementation Method 2
The positive current collector includes a support layer and a metallic conductive layer
Data Source
AI summary
This application provides a lithium-ion battery, including: an electrode assembly and an electrolytic solution.The lithium-ion battery may satisfy the following condition:0.6≤α≤0.9, and 4≤w×α/β1≤25,where, α=La/Lc, La is an arc length of a convex surface of the negative current collector corresponding to a concave surface of an innermost first circle of positive electrode in a jelly-roll structure of the electrode assembly, Lc is an arc length of a concave surface of an innermost first circle of positive current collector in the jelly-roll structure of the electrode assembly, and La and Lc are measured in mm; w is a percent of the first lithium salt LixR1(SO2N)xSO2R2 by mass in the electrolytic solution; and β1 is a thickness of the metallic conductive layer in the positive current collector, measured in μM.