Page 44 - EE Times Europe Magazine – November 2023

44 EE|Times EUROPE

Unveiling Trends and Insights in Solid-State Battery Technology

Polymers Oxides Sulfides

· Easy and cheap to · Stable in ambient · High ionic conductivity
process atmosphere
· Good interfacial
· Compatible with · Good mechanical contact
existing and electrochemical · Scalable
manufacturing properties
· Good mechanical
· Good interfacial · High mechanical and electrochemical
compatibility strength
properties
· Very flexible · Safe
· High reactivity with
· Low anti-oxidation · High interfacial water and air
potential resistance and · Toxic by-product can
compatibility issue
· High operational be easily generated
temperature typically · Difficult to scale up · High pressure needed
required
· High sintering for charge/discharge
· Low ionic conductivity temperature required
· Inert gas condition
· Not completely · Brittle and easy to may be required for
inflammable break production
· Limited energy density · Limited solvent
improvement and binder
selection
Comparison of solid-state batteries (Source: IDTechEx)

batteries, and the premium price of SSBs, they level. Cell-level efforts will only be part of areas, and therefore, the ideal temperature
need to present clear value propositions to future endeavors. We have seen that the required for SSBs may be different from Li-ion
be accepted by the public. Although there is development focuses have experienced a batteries.
quite a lot of research discussing if SSBs can transition from material development and Additional efforts need to be put into
lead to better safety, more evidence shows cell demonstration to cell validation and equipment utilization, factory footprint, sup-
that they do offer higher abuse tolerance. system design. Examples include cell-to- ply chain establishment and manufacturing
pack (CTP), thermal management systems yield improvement.
The development of SSBs and mechanical designs. WHAT COULD WE SEE?
CTP is not a new concept, and it can be
has evolved into a global found in designs based on Li-ion batteries, The polymer-based solid-state battery has
endeavor characterized such as BYD’s blade battery and CATL’s CTP already been commercialized and used in
vehicles, such as the case of Daimler eCitaro.
designs. The CTP concept will become more
by regional interests and important due to the better safety and bipolar Other technologies are continuously testing
substantial governmental stacking possibility of SSB cells. Battery their samples for OEMs. With Toyota’s
safety means a more flexible pack design and
announcement of a technological break-
support. fewer electronics and components used in through, efforts are expected to be put into
further material development and device
the battery modules/packs. For example, the
bipolar design enables closer packing and optimization. In the meantime, more focus on
Heightened energy density is another higher energy density, leading to potentially system design is expected.
advantage many people talk about regard- higher energy density and comparable cost at The market may not care whether small
ing what SSBs can further bring. However, the system level. amounts of liquid or gel polymers are used
the improvement should pair with new It is possible that initial generations of as part of SSBs. As long as batteries provide
cathode and anode materials. For instance, solid-state batteries may not be equipped required features, end users accept them.
most SSEs, especially inorganic solid-state with high-voltage, high-capacity cathode Because hybrid semi-solid batteries can
electrolytes, have higher density than the and lithium metal anode, thus leading to still provide improved performance, they
polyolefin separator. They are also typically lower energy densities than commercial could provide a good transition route. In the
thicker than separators used in conventional Li-ion batteries. It is also expected that short term, we may see more examples with
Li-ion batteries. If the electrodes are kept the initial costs of solid-state battery cells hybrid SSBs. With maturing technological
the same (for example, still graphite anode are higher than their Li-ion counterparts. development, ASSBs may act as the ultimate
and layered metal oxide cathode), most SSBs However, with a higher energy density at destination.
end up with lower gravimetric energy density pack level with a flexible design and fewer As the largest potential market, automotive
compared with Li-ion batteries. On the other materials/components used, it is possi- is the target for almost all SSB vendors. In the
hand, this can also bring opportunities for ble that solid-state battery packs can be meantime, niche applications that require
material development. comparable to or even better than Li-ion more abuse tolerance and are less sensitive
There are also arguments and uncer- batteries. to price can be the lower-hanging fruits for
tainties on whether power, charge rate The thermal management system cannot SSBs. ■
and cycle life can be improved. However, be eliminated for SSBs but may be operated
all the discussions remain at the cell in a way that targets different safe operating Xiaoxi He is a research director at IDTechEx.

NOVEMBER 2023 | www.eetimes.eu