Uchikura & Co., LLC

Sanyo's Legacy: How Eneloop Technology Helped Power the Tesla Roadster

 

When people think of Tesla, they usually think of cutting-edge electric vehicles designed in Silicon Valley. Few realize that some of the technology that helped make Tesla's first production car possible originated in Japan.

 

Sanyo Electric, once one of Japan's leading electronics companies, was a pioneer in rechargeable battery technology. In 2005, Sanyo introduced Eneloop, a revolutionary low-self-discharge rechargeable nickel-metal hydride (NiMH) battery. Eneloop became famous because it could hold its charge for months, making rechargeable batteries practical for everyday use. Even today, Eneloop batteries remain popular around the world.

 

While Eneloop itself was designed for AA and AAA batteries, Sanyo's expertise extended far beyond consumer products. The company was also a major manufacturer of lithium-ion battery cells.

 

When Tesla developed the original Tesla Roadster, introduced in 2008, it chose to build its battery pack using thousands of small cylindrical lithium-ion cells rather than a few large battery modules. Many of these cells were supplied by Sanyo, whose manufacturing quality and reliability played an important role in the success of Tesla's first electric sports car.

 

In 2009, Panasonic acquired a majority stake in Sanyo Electric, and the company eventually became part of Panasonic. The battery technologies, manufacturing experience, and engineering talent developed by Sanyo continued to contribute to Panasonic's position as one of the world's leading battery manufacturers.

 

Panasonic later became Tesla's primary battery partner for many years, supplying cells for vehicles such as the Model S, Model X, Model 3, and Model Y. The partnership helped accelerate the global adoption of electric vehicles.

 

Although the Sanyo name has largely disappeared, its technological legacy lives on. Every time someone uses an Eneloop battery or drives a Tesla powered by Panasonic cells, they are benefiting from decades of Japanese engineering and innovation.

 

Sometimes the companies that make history are not the ones whose names remain in the spotlight—but their technology continues to shape the future.

 

PS: Today, Tesla sources batteries from several manufacturers around the world. While Panasonic remains an important partner, especially for some vehicles produced in the United States, a significant portion of Tesla's batteries are now supplied by Chinese manufacturers such as CATL, particularly for vehicles built in China and many models using lithium iron phosphate (LFP) battery technology. This reflects the rapid growth of China's battery industry and Tesla's strategy of sourcing batteries from multiple suppliers around the world.

 

PPS: PSPINC also had the privilege of working with Sanyo Electric's Computer Division during the early days of Japan's personal computer industry. Sanyo was one of the founding members of the AX computer standard, an ambitious effort to bring Japanese-language support to IBM PC-compatible computers. Although AX was eventually overtaken by Microsoft's DOS/V technology, it remains an important chapter in Japan's PC history. It was an honor for PSPINC to have worked with Sanyo during that exciting period of technological innovation.