(Chris Devlin) #1



ies’ biggest buyer is Airbus. As part of a
program dubbed Zephyr, Airbus is testing
them on unmanned planes known as high-
altitude pseudo-satellites, or HAPS. Last
December, the two companies announced
that one of the Airbus vehicles powered by
Amprius batteries flew for more than 25
days, “setting a new endurance and altitude
record for stratospheric flight.”
To Sun, the Airbus contract is both a
lifeline and a yellow flag. “We charge them
a crazy price” for the batteries, he says.
“That kind of price is not sustainable.” The
batteries crafted in Sunnyvale, in other
words, are akin to suits sewn on Savile
Row: bespoke, expensive, and therefore at
risk. “If it cannot scale up,” Sun says of the
California operation, “it will die.”
Airbus has compelling reasons to pay
Amprius’s price. It is trying to outpace its
rivals, including Boeing, in developing and
commercializing both a less-expensive
alternative to satellites and a viable fleet
of electric-powered air taxis. “There are
hundreds of startups out there” claiming
they have the next big thing in batteries,
says Mark Cousin, chief executive of A^3 by
Airbus, an innovation center the company
has set up in Sunnyvale, not far from Am-
prius. But, other than Amprius, “we’ve not
seen any evidence that any of the companies
are close to having something that could po-
tentially be mature enough to be integrated
into a product in the short to medium term.”
In China, meanwhile, Amprius is chasing
a broader market. In Nanjing, the southern
Chinese metropolis in which Sun grew up,
Amprius has another laboratory where it’s
developing an anode material less rarefied
than its silicon-nanowire technology but
still more advanced than the industry norm.
It’s a nanoscale structure of silicon manu-
factured as a powder and then combined
with traditional graphite powder. The
resulting graphite-silicon mixture is run
through a conventional battery plant. This
modest silicon boost typically raises a bat-
tery’s energy density by up to 15% beyond a
traditional lithium-ion battery’s. That’s far
less than the improvement from the silicon-
nanowire material, but it’s radically cheaper.
On the morning I visit Nanjing, dozens
of bags of the silicon powder are stacked

on a metal shelf. To my untrained eye, they resemble ground coffee,
differing only in their shade of brown. Some evoke French roast;
others, a lighter blend. Amprius is supplying the material to various
U.S., European, Japanese, Korean, and Chinese automakers for test-
ing. It also trucks the powder to a factory in nearby Wuxi that was
built for Amprius in 2016.
When I visit the Wuxi factory, it’s cranking out batteries for
children’s smartwatches and for consumer battery packs. The
factory also makes batteries for a Chinese dronemaker. Chuanxin
Zhai, a scientist there who has been dispatched to walk me around,
says he’s particularly proud the factory won a recent contract for
the watch batteries. It did so after an intense competition over
energy density with Amperex Technology Ltd., or ATL, a Chinese
company that’s one of the biggest battery makers in the world. Zhai
mentions another customer for which the Wuxi factory has made
batteries: a firm that uses them to make cold-weather oxygen-
supply machines. That firm, he says, sells the machines to the
Chinese military, for medical use in Tibet.



Shipping con-
tainers holding
Vionx “flow”
battery to store
electricity pro-
duced by this
wind turbine
in Worcester,