SoftBank mulls over tie-up with 3DOM in race to develop batteries

SoftBank Group’s telecoms arm is considering battery technology from 3DOM as the investment giant pushes further into wireless communications projects that use flying devices, according to the Japanese startup.

3DOM’s technology is likely to be used for future mobility applications that require high-battery capacity, such as flying taxis or drones, 3DOM vice-president Shusuke Oguro said.

3DOM is working on lithium-metal batteries, which are more energy dense and charge much faster than lithium-ion batteries. The seven-year-old firm announced plans in August to list in Singapore via a reverse takeover of restaurant operator Chaswood Resources Holdings.

“We are in contact with 3DOM but not able to comment in further detail,” said a spokesperson for SoftBank, the Japanese tech conglomerate’s publicly traded telecom unit.

SoftBank’s interest in high-power batteries is part of Masayoshi Son’s ambition to get ahead in the race towards 6G. In March, it teamed with US-based Enpower Greentech to develop technologies for lithium-metal batteries that may be applied in cellular base stations and it has plans to deploy drones that would serve as base stations for mobile phones when natural disasters damage the ones on land.

One big drawback of lithium-metal batteries, however, is that as the battery charges, lithium ions can form spiky structures on the anode called dendrites. These dendrites can grow long enough to reach the other electrode and short circuit the battery, potentially causing a fire. It’s a bigger problem for lithium metal than for other anode materials like graphite.

To that end, 3DOM is developing polyamide separators for lithium-metal batteries that decrease the possibility of punctures and short circuits. Polyamide is a material that can withstand extreme heat. The company’s public debut, which should occur by March, will allow it to more easily fund mass production of the separators, Oguro said.

“It’s about thinking outside the box,” said Oguro, worked at Panasonic for about 35 years on lithium-ion battery development. When 3DOM founder Kiyoshi Kanamura presented the solution more than a decade ago, “people said the separators would be hard to mass produce. For me, this is a big turning point.”

Scientists around the world have for years been looking at ways to solve the dendrite issue in the hope of developing more powerful electric-car batteries. 

Harvard University associate professor Xin Li, who heads a research group that focuses on the design of next-generation energy storage materials, wrote in an article published in May that multilayer battery designs do exist that allow dendrites to be contained. But he noted there’s a “long way to go” to commercialise the technology and scaling up is important.

3DOM’s separator has tiny holes that let ions flow smoothly, thus making uniform chemical reactions and allowing better dendrite control. The separator is soft and bendable and less costly to make than ceramic versions, Oguro said.

The company, which has received about ¥8.1bn ($74m) in financing from angel investors it did not name, has recruited about 90 engineers from companies including Panasonic, Nissan and Honda.

3DOM isn’t the only battery maker developing lithium-metal cells. QuantumScape, which counts Volkswagen and Bill Gates as backers, is developing solid-state lithium-metal batteries that replace the polymer separator with a solid-state separator that prevents dendrites. Cuberg, which was acquired by Sweden’s NorthVolt in March, has a battery based on a nonflammable electrolyte combined with a lightweight lithium metal anode.

Oguro said 3DOM plans to start mass producing its separators later this year and begin making batteries that use the separators by the end of 2022.

Bloomberg News. More stories like this are available on bloomberg.com