Bipolar batteries achieve better performance by combining the anode and cathode terminals in the same pantograph. Before, the anodes and cathodes had their own collectors.
The new arrangement not only saves space, it delivers a greater flow of electricity.
On a large scale, the cost of manufacturing the batteries is lower because they have fewer components. But right now, output is limited. The bipolar batteries are manufactured by the group’s subsidiary Toyota Industries Corp., which currently has only enough capacity for 240,000 vehicles per year.
For traditional nickel-metal hydride batteries, however, Toyota buys about 1.6 million units a year, primarily from Primearth EV Energy Co. in Japan, as well as sources in China.
Okumura said it is a misconception to believe that nickel-metal hydride batteries are old and lithium-ion batteries are new. The development of the two types started around the same time, he said. But it’s just that nickel metal hydride first came on the market.
“The public has the image that nickel metal hydride batteries are an old battery, but they actually are not,” Okumura said. “We started developing this new type of nickel metal hydride battery because after 20 years of using it, there was a record of performance.
“But the basic design has not changed significantly,” he said. “So we decided to take up the challenge of increasing production.”
Due to the strong power and output, the new batteries are best suited for hybrid cars that require fast power outages, as opposed to electric cars that need a large energy store.
Toyota places lithium-ion as its main electric car battery. But Toyota believes the bipolar structure can also be applied to lithium-ion batteries, leading to potential improvements in these power packs.