Rechargeable batteries are an integral component of energy-storage systems for Tesla electric vehicles and for grid storage. Li-ion-based batteries are a common type of rechargeable battery in the world. Electrolyte additives have been shown to be operative and increase the lifetime and performance of Li-ion-based batteries.

Various studies show that electrolyte additives to increase cycle life compared to an electrolyte system with no or only one additive. However, researchers typically do not understand the interaction between different additives that allow them to work together synergistically with the electrolyte and specific positive and negative electrodes. Thus, the composition of additive blends of certain systems is often based on trial and error and cannot be predicted beforehand.

Prior studies have not identified two-additive electrolyte systems that can be combined into a lithium-ion battery system to yield a robust system with sufficient properties for grid or automobile applications.

Tesla researchers have studied this issue in more detail and have applied for a patent "New battery system based on lithium difluorophosphate"

Application Date: January 29, 2020
Patent Publication Date: August 6, 2020

FIG. 3 is a schematic diagram of a lithium-ion, battery-cell system
Source: Tesla patent

The present disclosure relates to rechargeable battery systems, and more specifically to the chemistry of such systems, including operative electrolyte additives and electrodes for improving the properties of the rechargeable lithium-ion-battery systems.

This disclosure covers novel battery systems with fewer operative, electrolyte additives that may be used in different energy storage applications, for example, in vehicle and grid-storage. More specifically, this disclosure includes two-additive electrolyte systems that enhance performance and lifetime of Li-ion batteries, while reducing costs from other systems that rely on more additives. This disclosure also discloses effective positive electrodes and negative electrodes that work with the disclosed two-additive electrolyte systems to provide further systematic enhancements.

Tesla is actively working on developments that will increase battery life. At the moment, the company has already achieved incredible progress and will soon begin its own production. We can get more information on this at Battery Day, which will take place on September 22nd.