Fluorochemistries to unlock lithium-ion battery potential

Research into lithium-ion battery technology has been given a boost through the awarding of a US$1 million grant to Daikin America by the Department of Energy (DoE) to develop advanced high performance electrolytes based on fluorochemistries.

This technology will allow lithium-ion batteries to operate at higher voltages and temperatures “Daikin has developed unique fluoroadditive and fluoro co-solvent compounds that when added to electrolyte, can increase the performance of next generation lithium-ion batteries. The development of these electrolyte chemistries will be a critical element needed by the industry to achieve the cost and performance targets for lithium-ion batteries set by the DOE and the USABC (United States Advanced Battery Consortium),” says Ron Hendershot, Director of R&D for Daikin America. With respect to lithium-ion battery safety, a conventional lithium-ion battery contains fuel (electrolyte), an oxidizer (active component) and multiple potential ignition sources.

Fires in lithium-ion cells are due to the interaction of the fuel in the active component with a source of ignition such as a spark or heat. The most viable safety solution, says the company, is to significantly reduce the flammability of the electrolyte by increasing the fluorochemical content by 20% or more. According to Daikin, separate independent laboratories have shown that this strategy leads to superior cycling behavior compared to conventional hydrocarbon electrolytes.

Daikin is working closely with the scientists at a number of national laboratories such as Argonne National Laboratories, Lawrence Berkeley National Laboratories, and Sandia National Laboratories. The Orangeburg, New York-based Daikin America is a wholly-owned subsidiary of the Osaka, Japan-based Daikin Industries, which is a leading manufacturer of air conditioning, refrigeration equipment and fluorochemical products. Daikin America is one of the largest fluoroproduct suppliers in the world. It provides molding resins, fine powders, aqueous dispersions, melt processable fluoropolymers, fluoroelastomers, and high performance fluorochemicals for many critical applications including automotive.

In August 2012, Daikin opened a new electrolyte manufacturing facility in Decatur, Alabama. The company has production facilities in all major regions and technical service support systems in the US. Clients include OEMs, Tier 1 and Tier 2 suppliers of components and assemblies in areas such as powertrain sealing. Daikin is expanding its position in the energy storage materials market with the introduction of high-performance fluorinated electrolyte solutions for lithium-ion batteries and for electric double layer capacitors (EDLCs) or ultracapacitors. Daikin has also developed a VDF copolymer which is superior to PVDF when used as a binder resin for lithium-ion battery systems.

Automotive Industries (AI) asked Hendershot what the DoE grant means for Daikin America.

Hendershot: Being recognized by the DoE will help strengthen Daikin’s brand and image. It confirms that Daikin has electrolyte additive technology that can improve the capabilities and performance of lithium-ion batteries. This, in turn, will help open more doors where the industry can take advantage of our technologies and improve lithium-ion battery technology.

AI: What R&D set up does Daikin America have?

Hendershot: Daikin America, and its parent company, Daikin Industries of Osaka, Japan have significant resources dedicated to the development and testing of energy storage materials, which includes lithium-ion battery electrolytes. We have been very successful in attracting world class technical experts to join our teams. These experts will be actively involved in the execution of the DoE grant program.

AI: Tell us about the work Daikin is doing in advanced high performance electrolytes, based on fluorochemistries.

Hendershot: Daikin is developing advanced electrolyte formulations containing solvents and/or additives based on proprietary fluorochemistry. The solvents/additives have increased electrochemical, chemical and thermal stabilities due to the inherent strength of the carbon-fluorine bond. Daikin is accomplishing direct performance and longevity measurements of these materials in batteries at our Decatur, Alabama research labs. The thermal properties of these electrolytes, as they relate to the other active materials in batteries, are being studied in an effort to make safer, more reliable lithium-ion batteries.

AI: What progress is Daikin making with battery manufacturers and national level laboratories?

Hendershot: As the battery makers push the operating voltages for the next generation lithium-ion batteries to 4.3V and higher, they are finding that conventional, non-fluorinated co-solvents and additive packages for electrolytes cannot deliver the life cycle performance that they have guaranteed at lower operating voltages. Fluorinated compounds are needed to stabilize electrolytes so that current and longer life cycles can be achieved at these higher operating voltages.

AI: What impact do you hope your formulations will have on the growth of EVs and PHEVs?

Hendershot: It is well known that that the $/KWhr cost for lithium-ion batteries must drop precipitously from where it is today to drive EV and PHEV prices to the inflection point, where demand would accelerate. Making higher voltage batteries with higher energy densities that have 10+ year warranties are the critical elements needed to reach the price points to accelerate sales. The development of stable battery electrolytes is one of the key elements of this effort. Daikin, with its unique fluorochemical technology, has one of the enabling technologies needed to allow these performance targets to be met.

AI: Describe to us Daikin America’s new manufacturing facility located in your fluoroproduct plant complex in Decatur, AL.

Hendershot: This facility has the ability to make any custom electrolyte formulation for lithium-ion batteries. The flexibility of the plant is key, as there are virtually no two electrolyte formulations in the industry that are the same. All of Daikin’s fluorochemical compounds can be added at either the co-solvent or additive level. The Decatur plant, including the electrolyte mixing facility, is ISO 9001:2008 and ISO 14001 certified. The Decatur plant was also named Medium Manufacturer of the Year by the State of Alabama for 2013.

AI: How do you see the growth in lithium-ion batteries evolving over the next few years? Hendershot:

Daikin sees next generation of lithium-ion battery technologies being introduced to the market starting in 2014. These technologies will lower the cost of lithium-ion batteries and increase their use in many transportation, energy storage, and industrial markets. We believe Daikin will be an active participant in this growth because of our unique fluorinated electrolyte technology