Ketone-Based Electrolytes for Low-Temperature Lithium Ion Batteries
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Solution Overview
Problem
Current lithium ion battery electrolytes, particularly carbonate-based ones, are not effective at low temperatures, limiting the performance of hybrid electric vehicles and plug-in hybrid electric vehicles, as they decompose due to Lewis Acid interactions with ketone solvents, leading to instability and reduced battery power.
Innovation Solution
Development of ketone-based solvents such as 2,4-dimethyl-3-pentanone, 3,3-dimethyl-2-butanone, and 2-butanone, combined with non-Lewis Acid salts like Li2[B12F12] and LiBOB, and the use of SEI forming additives to enhance stability and performance, particularly at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If carbonate-based electrolytes are used, then room temperature performance is optimized, but low temperature performance deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by replacing carbonate-based solvents with ketone-based solvents (such as 2,4-dimethyl-3-pentanone, 3,3-dimethyl-2-butanone, and 2-butanone) combined with non-Lewis Acid lithium salts. This parameter change enables the electrolyte to maintain stable performance across a wide temperature range, particularly improving low temperature operation while preserving room temperature power performance.
2Temperature
If ketone-based solvents are used, then low temperature performance improves, but stability deteriorates due to Lewis Acid interactions
Solution Approach 1:
The patent introduces non-Lewis Acid lithium salts (such as Li2[B12F12] and LiBOB) as intermediary substances that mediate between the ketone-based solvent and the electrode materials. These salts do not exhibit Lewis Acid behavior, thereby preventing the destabilizing interactions that would otherwise occur between traditional lithium salts and ketone solvents, thus maintaining electrolyte stability while enabling low temperature operation.
3Ease of manufacture
If traditional lithium salts are used with ketone solvents, then cost is reduced, but decomposition increases due to Lewis Acid component
Solution Approach 1:
The patent employs conventional, cost-effective ketone-based solvents that are readily available and inexpensive to manufacture. By combining these affordable solvents with non-Lewis Acid lithium salts, the patent achieves a low-cost electrolyte formulation that maintains high reliability and resistance to decomposition, eliminating the need for expensive specialized additives while ensuring long-term stability.
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
These electrolytes demonstrate improved stability, power performance, and the ability to operate effectively at low temperatures, extending battery life and enhancing the performance of lithium titanate electrodes in lithium ion batteries.
Implementation Method 1
the higher reactivity of ketones with the electrolyte salt, caused by the Lewis Acid component of the lithium salt coordinating and destabilizing the ketone moiety
Implementation Method 2
the ability of the electrolyte to conduct lithium ions
Implementation Method 3
the addition of an SEI forming additive allowed the materials to cycle well against a graphite anode
Data Source
AI summary
A family of electrolytes for use in a lithium ion battery. The genus of electrolytes includes ketone-based solvents, such as, 2,4-dimethyl-3-pentanone; 3,3-dimethyl 2-butanone(pinacolone) and 2-butanone. These solvents can be used in combination with non-Lewis Acid salts, such as Li2[B12F12] and LiBOB.