Toyota, Idemitsu in solid state battery collab

TOYOTA Motor Corporation is collaborating with Japanese oil and energy company, Idemitsu Kosa on developing mass production solid-state batteries (SSBs) for battery electric vehicles (BEVs) by the end of this decade.

Idemitsu has been engaged in developing SSB technology for a number of years; the agreement with Toyota aims to both develop mass production technology for solid electrolytes, improving productivity and the establishment of a supply chain to achieve the production capacity required for BEVs to adopt solid state batteries.

The collaboration is aiming for successful commercialisation of SSBs by 2027-28 followed by full-scale mass production. It is a similar timescale to Nissan’s stated goal of launching a BEV with SSBs “that have been developed in-house” by 2028.

Advantages of SSBs include the promise of greater energy storage density, increased reliability and wear resistance, faster charging and improved operational safety.

While other types of batteries use liquid electrolytes that can become volatile and flammable at high temperatures. SSBs use solid electrolytes that have high thermal stability which limits the risk of fire or explosion.

SSBs also have a higher energy density – up to 10 times greater than the lithium-ion cells in widespread use today – meaning they can be lighter and more compact.

In addition, a modern lithium-ion battery pack in a BEV typically lasts between 2000 and 3000 cycles before showing noticeable degradation whereas a high-density solid-state battery can approach 10,000 cycles.

Idemitsu has been working on next-generation battery technology to support the evolution of BEVs since 2001, while Toyota started in 2006.

The collaboration focuses on sulfide solid electrolytes, which are seen as a promising material to achieve high capacity and output for BEVs.

Sulfide solid electrolytes are characterised by softness and adhesiveness to other materials, which is suitable for battery mass production.

Idemitsu was already well down the development path for production technologies of lithium sulfide which is an intermediate material for solid electrolytes, using byproducts generated during petroleum refining.

It has also been working on development of mass production technology on sulfide solid electrolytes, aiming to establish a stable supply system and the company is steadily increasing the capacity of its small pilot facility and is proceeding with the construction plan of a large pilot facility which will contribute to commercialisation of all-solid-state batteries in 2027-28.

Through the combination of both companies' material development technologies; Idemitsu's material manufacture technologies and Toyota's battery processing and assembly technologies which is obtained through BEV development, the pair aim to realise mass production of both solid electrolytes and all-solid-state batteries suitable for global widespread use. 

Toyota Motor Corporation president and CEO Koji Sato said: “Our two companies will combine their separate efforts to mass-produce new materials and establish a supply chain for solid electrolytes, which hold the key to the commercialisation of solid-state batteries.

“First, between 2027 and 2028, we will start to produce solid-state batteries for use in battery electric vehicles. We will then lay the foundation for mass production.

“We are developing optimal solutions in line with specific applications and characteristics, including high-output and long-range batteries, as well as high-quality and affordable versions for widespread use.

Idemitsu Kosan president and chief executive officer Shunichi Kito said: “It is not potential or dreams but the ability to realise them that is being put to the test.

“Idemitsu will support Toyota's ability to realize the commercialisation of all-solid-state batteries for battery EVs with technological strength through manufacturing and mass-producing the solid electrolytes used in such batteries.

“Our target for commercialisation is 2027 or 2028.

“It means that the commercialisation of solid-state batteries is a thing of the future that is now within reach.”