Tesla filed a patent 'Dioxazolones and nitrile sulfites as electrolyte additives for lithium-ion batteries'

by Eva Fox January 28, 2020

Tesla filed a patent 'Dioxazolones and nitrile sulfites as electrolyte additives for lithium-ion batteries'

Among all electric car manufacturers, Tesla has an undeniable leadership in the development of rechargeable batteries. This is the result of a large investment in research and development. The company has long been developing reliable batteries and is striving to increase their quality to an even higher level.

Tesla filed a patent 'Dioxazolones and nitrile sulfites as electrolyte additives for lithium-ion batteries'
Application Date: July 25, 2018
Publication Date: December 26, 2019

Improved battery systems have been developed for lithium-ion based batteries. The improved systems include a nonaqueous electrolyte including one or more lithium salts, one or more nonaqueous solvents, and an additive or additive mixture comprising one or more operative additives selected from a group of disclosed compounds, including 3-aryl substituted 1,4,2-dioxazol-5-ones and 3-phenyl-1,3,2,4-dioxathiazole 2-oxide.

Batteries are an integral component of energy storage systems for electric vehicles and for storage on the network (for example, for backup power during a power outage, as part of a micro network, etc.). Li-ion batteries are a common type of battery.

Electrolytic additives have been shown to work and increase the life and effectiveness of lithium-ion batteries. However, researchers, as a rule, do not understand the interaction between the various additives, which allow them to synergistically interact with the electrolyte and specific positive and negative electrodes. Thus, the identity of certain systems is often based on trial and error and cannot be predicted in advance.

For further progress in the use of electric vehicles and energy storage systems from the network, it is desirable to develop the chemistry of lithium-ion cells, which provides a longer service life at high temperatures and high voltage cells without a significant increase in cost. The introduction of sacrificial electrolyte additives on the order of a few weight percent is a practical method to form protective solid-electrolyte interphase (SEI) layers that limit electrolyte decomposition during cell storage and operation. In recent years, significant efforts have allowed to obtain a large number of such additives that can be used to improve the characteristics of cells for various applications.

This patent provides compositions for use as electrolyte additives in lithium-ion battery systems and relates to the chemical composition of rechargeable battery systems, including active electrolyte additives, to improve the properties of rechargeable lithium-ion battery systems.

This disclosure covers new battery systems with fewer active electrolyte additives that can be used in various energy storage applications, for example, in vehicles and power systems. More specifically, this disclosure includes additive electrolyte systems that enhance performance and lifetime of lithium-ion batteries, while reducing costs from other systems that rely on more or other additives. This disclosure also provides methods for preparing the additives disclosed herein.

Certain embodiments described herein include a nonaqueous electrolyte for a lithium ion battery comprising at least one lithium salt, at least one nonaqueous solvent, and an additive component comprising at least one operative additive. The at least one operative additive is selected from

 (a) the group consisting of 3-aryl substituted 1,4,2-dioxazol-5-one compounds according to Formula (I):

 (MOL) (CDX)

      wherein R is any aromatic substituent, any unsaturated aliphatic substituent, or any aliphatic substituent containing one or more fluorine atoms; or
(b) the group consisting of 3-CRR′R″ substituted 1,4,2-dioxazol-5-one compounds according to Formula (II):

 (MOL) (CDX)
      wherein each of R, R′, and R″ is hydrogen, alkyl substituents, or aromatic substituents; or
      (c) the group consisting of R-substituted nitrile sulfite compounds according to
      Formula (III):

 (MOL) (CDX)
      wherein R is any alkyl or aromatic substituent.

FIG. 3 illustrates a schematic of a lithium ion cell 300. Lithium ions 350 are dispersed throughout electrolyte 320, within container 360. Container 360 may be part of a battery cell. The lithium ions 350 migrate between positive electrode 330 and negative electrode 340. Separator 370 separates the negative electrode and positive electrode. Circuitry 310 connects the negative electrode and positive electrode.

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