To reduce the carbon footprint of cars and trucks worldwide, many automotive engineers, designers and manufacturers are pushing to expand the feasibility, supply and affordability of all-electric vehicles. A primary focus is the development of a battery for efficient energy storage.
Current-production electric vehicles from various manufacturers (Tesla, Toyota, General Motors) use batteries with a liquid or gel electrolyte. The lithium-ion (Li-ion) battery, developed and perfected over the past quarter-century or more, has proved its worth in millions of consumer articles and certainly in cars. But Li-ion technology is heavy, inefficient, and fire-prone. To address the fire issue, in automotive applications where large banks of them are in use, Li-ion batteries need to be cooled during operation. The added cost and complexity for the manufacture and maintenance of these systems is considerable.
As a result, many manufacturers and allied researchers are looking into the development and refinement of the solid-state battery (SSB) for automotive energy storage. Such a battery, which has been developed and successfully field tested for small scale applications such as pacemakers, is projected to be smaller, lighter, more flexible, more efficient and faster charging than an Li-ion battery of similar output. The original design for the pacemaker SSB, still in use today, placed a sheet of lithium metal in contact with a film of solid iodine. The current output of this design is low but steady and lasts a long time. An improvement to this design, using a sulphide-based material was developed in Japan in the past decade.
Designing and manufacturing affordable high-output SSB in large quantities remains a major hurdle. Asian companies appear to have a head-start toward developing this class of battery on a large industrial scale. Toyota, Nissan and Honda and Panasonic recently formed a team of researchers to further develop SSB technology, though shortly after the team’s formation, Nissan management expressed some reservations and pulled back its support. In Europe, Tesla’s offshoot Northvolt has secured funding for a major SSB research effort. Volkswagen in Germany and Dyson in the UK have also launched major research efforts, but Bosch dismantled its research effort.
The likelihood of mass-produced cars with SSB as the power source before the decade of the 2020s is remote. Even as we enter that decade, it may be several years before the technology matures to the point that it can become widespread. But many manufacturers apparently believe that SSB is the future of automotive energy storage