Solid-state
batteries are smaller, lighter, and safer. China’s Contemporary Amperex
Technology Co., Limited (CATL) is readying up to manufacture solid-state
lithium batteries. CATL is a world leader in lithium-ion technology. They plan
to achieve small-scale production by 2027. They plan to make lithium-sulfur (Li-S)
batteries with an impressive 40% increase in energy density to 500Wh/kg. Just a
few weeks ago I wrote about Li-S
battery technology but did not include much of CATL’s efforts. However, as
I noted, charging speed and life cycle still have challenges. With the
successful mitigation of the polysulfide shuttling effect, the cycle life issue should
be able to be overcome. CATL’s production stage began with 1Ah samples and then
moved on to 10Ah. Now they are working with 20Ah samples in order to explore
actually producing the batteries. 20Ah is the pouch battery size that will go
into EVs. Li Zinan wrote a great article for Late Post that explains the
progress of solid-state batteries and CATL’s efforts and challenges. The quotes
are from the article.
“Zeng Yuqun, chairman of CATL, divided the R&D
progress of solid-state batteries into nine levels, and he said at the power
battery conference in September this year that CATL is currently at level 4,
and the goal is to increase to level 7-8 by 2027 to achieve low-volume
production of all-solid-state batteries.”
“CATL's planning timeline is similar to that of Toyota,
LG Energy Solution, Samsung SDI, etc., and slightly faster than BYD. But Zeng
Yuqun made a rare high-profile claim in September that CATL's research was
"a big step ahead" of its rivals, and in English it was "second
to none."
The liquid
lithium-ion batteries currently in use have limitations on energy density (about
350 Wh/kg) that are unlikely to be overcome. Solid-state lithium batteries may
be an option for aircraft of some kinds, but liquid lithium won’t be. Indeed, solid-state
lithium batteries will be the likely future of lithium batteries.
“Solid-state batteries, that is, the liquid electrolyte
(mainly lithium hexafluorophosphate) commonly used in lithium batteries is
replaced with a solid-state electrolyte. The performance of solid-state
electrolytes is more stable and safe, which allows the use of lithium metal
with higher energy density but more dangerous chemical properties as a negative
electrode (currently graphite) and a high-nickel ternary material with higher
lithium content as a positive electrode, doubling the upper limit of energy density
of lithium batteries to more than 700Wh/kg.”
Thus, we can see
there is the potential to double the current lithium energy density with solid-state
batteries.
“Wu Kai said in the middle of last year, "If Toyota
says that it can produce all-solid-state batteries today, I am skeptical, and
no one in the industry currently has the ability to mass-produce
all-solid-state batteries." As for whether it will be mass-produced in
2027, as a technician, it is difficult for me to say accurately.”
“However, in March this year, Wu Kai, chief scientist of
CATL, shared CATL's all-solid-state battery R&D progress at a battery
industry technology forum. Half a year later, Zeng Yuqun disclosed the
timetable for "small-scale mass production of all-solid-state batteries in
2027".
Toyota also announced
that it would mass-produce solid-state batteries in 2027. However, as the Late
Post article in Chinese notes: Toyota has been touting solid-state batteries
since 2018 and just now has finally started talking about manufacturing, The
article also points out that there are semi-solid-state batteries (like some I wrote
about in my Li-S article) and full solid-state batteries, like the ones CATL
plans to make. Like Toyota, CATL chose Li-S batteries as its solid-state
battery since they have the “highest performance ceiling and the fastest
mass production progress.” The three contenders for solid-state lithium
batteries are sulfide, oxide, and polymer.
“These three technical routes have corresponding basic
shortcomings. The polymer electrolyte needs to be heated to 60°C to obtain
sufficient conductivity, which is difficult to use under normal working
conditions. low conductivity of oxide electrolytes; The conductivity of lithium
ions in sulfide electrolytes is similar to that of liquids, but they are easily
oxidized to produce toxic gases. In recent years, the industry has also
produced new technical routes such as halides, and as far as we know, BYD is currently
focusing on the research and development of halide solid-state batteries.”
Some problems
with sulfide batteries in addition to the polysulfide shuttling effect which
produces dendrites that can short-circuit the battery in time, are the increased
distance between electrolyte and electrodes which can make charging slow. There
are two other problems to be overcome. Sulfide electrolytes can react with the
water vapor in the air producing toxic gases and decreasing battery conductivity.
Sulfides are also expensive. The final problem to be overcome is difficulty in
manufacturing since existing lithium-ion facilities cannot be used for full
solid-state batteries. The manufacturing process needs to be re-invented, which
CATL is working to do. As I noted in the Li-S article, that is not a problem
with semi-solid-state batteries like those about to be produced by Lyten and
others. CATL uses high pressure to squeeze the electrodes closer together to
mitigate the charging issue.
“CATL has developed a technology of multi-layer material
to wrap the cathode, which is equivalent to using a multi-layer film to limit
the deformation of the electrode piece and improve the structural stability.
The contact interface between the positive and negative electrodes and the
solid electrolyte relies on a self-developed binder to maintain the fluidity of
the ions, i.e., the conductivity.”
“CATL has developed a technology of multi-layer material
to wrap the cathode, which is equivalent to using a multi-layer film to limit
the deformation of the electrode piece and improve the structural stability.
The contact interface between the positive and negative electrodes and the
solid electrolyte relies on a self-developed binder to maintain the fluidity of
the ions, i.e., the conductivity.”
Other
manufacturing breakthroughs include dry electrodes and isostatic integrated
molding. However, there are still engineering challenges to manufacturing to be
overcome including sustained high pressure to keep the electrodes in close
contact and better battery wrapping and packaging materials and processes need
to be developed and refined. It is expected that CATL will make about 0.5GWh of
Li-S batteries in 2027, enough for thousands of EVs but still a relatively
small amount for the market.
Samsung’s Solid-State Battery
Samsung is
working on a solid-state battery that hopes to achieve a 600-mile EV range,
9-minute charging, and a 20-year battery life. Samsung’s solid-state battery uses
oxide instead of sulfide as the cathode, which means lower performance but also
lower cost.
“We built a pilot line last year to mass-produce
all-solid-state batteries by 2027,” said Samsung SDI, as reported by The Elec.
Initial battery batches have been delivered to EV
manufacturers for testing. Unfortunately, as will be the case with other solid-state
battery producers as well, the high initial production costs will make the
initial EV prices very high. Thus, it is thought that solid-state batteries
will be a luxury item for a few years before mass production really takes off.
I have always said that the 2030s will be the decade when EVs improve enough in
performance and price to truly be competitive with ICE vehicles.
BYD’s Solid-State Battery
BYD head
scientist and engineer Lian Yubo thinks that solid-state EV batteries could be
in wide use in five years. BYD is a major manufacturer of lithium-iron-phosphate
(LFP) batteries, having 75% of the market share in China. Yubo thinks LFP
batteries will contribute to solid-state battery development. This early
rollout will likely be for high-cost luxury EVs.
Mercedes’ and Factorial’s Solid-State Battery
Mercedes has
joined forces with long-time U.S. solid-state battery developer Factorial to
co-develop their solid-state FEST (Factorial Electrolyte System Technology) for
Mercedes. The new battery tech is called Solstice. They expect an 80% increase
in range and high thermal stability resulting in far less fire risk. With
better thermal stability there is less need for cooling, which can also reduce
costs. They expect 600 miles of range, 40% less weight, and a 33% reduction in
size compared to current lithium-ion batteries.
Toyota’s Solid-State Battery
As noted, Toyota
has been working on solid-state batteries for a long time. They announced in
2023 that they plan to manufacture a solid-state battery that can charge in 10
minutes and get 745 miles of range on a full charge. Toyota has been promising
solid-state batteries since 2021 and delays have been common. The latest is
that they plan to introduce them in 2027/2028, with mass production coming
after 2030. Volkswagen, Hyundai, Nissan, and BMW plan to offer solid-state
batteries potentially before that. Below is Toyota’s battery tech roadmap from January
2024.
LPSO: A New Low-Cost Electrolyte
Another
improvement announced by Chinese scientists in July does not use lithium sulfide,
but a sulfide solid electrolyte called LPSO. According to a July 2024 article
in Interesting Engineering:
“The cost of sulfide solid electrolytes typically exceeds
$195 per kilogram, far above the $50 per kilogram threshold necessary for
widespread adoption. According to experts, this cost challenge arises from the
elaborate synthesis process of these electrolytes, which heavily relies on
costly Li2S.”
“This novel electrolyte is synthesized from two
inexpensive compounds, bringing the ingredient cost down to just $14.42 per
kilogram, which is less than 8 percent of the cost of raw materials for other
sulfide solid electrolytes, according to SCMP.”
“Remarkably, LPSO retains the key benefits of the
best-performing sulfide electrolytes, including compatibility with anodes that
ensures performance stability. It pairs well with high-energy-density anodes
such as lithium metal and silicon.”
Solid-State Batteries Still Have a Ways to Go Before They
Are Truly Mass-Produced
Despite the hype
and breakthroughs, solid-state batteries will not be available to the average
consumer anytime soon. They will begin as a battery for niche high-cost luxury
or high-performance EVs. It will likely be well into the 2030s before they will
be widely available to the average consumer. There are, however, some tweaks to
lithium-ion technology that are considered to be semi-solid-state batteries
such as lithium-silicon batteries and lithium-iron-phosphate (LFP) batteries. William
Clavey writes for Top Speed that the reason solid-state battery progress has slowed
comes down to cost-efficiency and reliability. The semi-solid-state choices
will likely be produced in the near term as full solid-state development continues.
Tesla is sticking with LFP batteries for now for their new-tech batteries due
to lower cost, increased performance, and lower (but not nil) fire risk than current
liquid lithium-ion batteries. Clavey also noted, referencing a meeting with silicon
battery developer Group 14, that battery deployment will indeed be based on
cost and reliability. That is why all vehicles still have lead-acid batteries
for basic power needs aside from powering the vehicle. They are cheap and
reliable.
References:
CATL
goes all in for 500 Wh/kg solid-state EV battery mass production. Aman Tripathi.
CATL goes all in for 500 Wh/kg solid-state
EV battery mass production
Solid
State Batteries Have Moved One Step Closer To Reality. William Clavey. Top
Speed. November 7, 2024. Solid State Batteries Have Moved One
Step Closer To Reality
Late
Exclusive丨CATL all-solid-state battery began
sample verification, with a team of thousands of people. Li Zinan. Ed. Cheng
Manqi. November 6, 2024. Late Post. Late Exclusive丨CATL
all-solid-state battery began sample verification, with a team of thousands of
people
Samsung’s
EV battery breakthrough: 600-mile charge in 9 mins, 20 year lifespan. Aman
Tripathi. Interesting Engineering. August 1, 2024. Samsung’s
20-year-life EV battery runs 600 miles on 9-minute charge
China:
Game changer solid electrolyte cuts solid-state battery price by 90%. Jijo
Malayil. Interesting Engineering. July 8, 2024. China:
Low-cost solid-state battery developed at 10% of current cost
Toyota
confirms 750 mi range solid-state EV battery plans to catch up to Tesla, but
when? Peter Johnson. Electrek. January 11, 2024. Toyota
confirms solid-state EV battery plans with 750 mi range
The
Advantages of Lithium-Ion Phosphate (LFP) Batteries for EVs. Eduardo Zepeda. June
4, 2024. Top Speed. The
Advantages of Lithium-Ion Phosphate (LFP) Batteries for EVs
BYD
exec predicts solid-state EV batteries will hit the market sooner than expected.
Peter Johnson. September 27, 2024. Electrek. BYD
exec says solid-state EV batteries will be here soon
Mercedes,
Factorial unveil new all-solid-state battery that can extend EV range by up to
80%. Peter Johnson. September 10, 2024. Mercedes
is getting new ultra-efficient all-solid-state EV batteries
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