As the markets for electric applications continue to grow, the technologies that power them continue to evolve today and in the future

BY
JOHN WARNER, Chief Marketing Officer
EnerDel
www.enerdel.com

 

The only constant in life is change. We have
heard it said hundreds of times, but it has turned out to be true time and
again. Batteries are no exception to that rule; as the markets for electric
applications continue to grow, the tech­nologies that power them continue to
evolve today and in the future. In my book, “The Handbook of Lithium-Ion
Battery Pack Design” (2015), I wrap up with a discussion on some of the trends
that will continue to drive battery development. To­day, just over a year after
publication, some of these trends are already beginning to emerge and some new
ones are emerging.

 

In this article, I discuss two types of
changes that are occur­ring in the battery world: evolutionary changes and
revolution­ary changes. Evolutionary changes are those that are continu­ous
improvements to current technologies. These are changes that are highly likely
and that we can expect to see within the next five years. However,
revolutionary changes are those that offer major improvements and often diverge
significantly from the current technologies. These are changes that are not
likely to be commercialized for at least 10 years or more, if at all.

 

Evolutionary changes

From a technology perspective, the demand
for power con­tinues to increase; therefore, demands on the battery increase,
which, in turn, drives us to continue to push the limits of these technologies.
In other words, as vehicles continue to power more of their systems
electrically and as more modes of transportation turn to electrification,
demands on the battery will only grow. In fact, in a recent webinar, one
research firm forecasts vehicle technology to largely transition to Energy
Independent Vehicles (EIVs) by the mid-2030s and predicts the end of the
internal combustion engine by about 2037. Higher energy density equates to
longer range, more power equates to faster acceleration, greater energy
volumetric energy density gives us smaller batteries, and greater gravimetric
energy densi­ty gives us lighter batteries. And there are technologies in devel­opment
today that move us in all of these directions — just not necessarily all in the
same technology.

 

In addition to the technology drivers, there
are some geopo­litical drivers pushing these technology trends. One is the fact
that the global population continues to
grow from about 3 billion people in 1960 to more than 7 billion in 2014, and
cur­rent forecasts show the world population reaching 8 to 10 billion by
2040–2050 (United Nations, 2014). This trend also has a secondary influence —
location. All current forecasts predict that most of this growth will be in the
world’s largest cities. This continuous population growth focused in these
“mega-cities” will drive the demand for electric trans­portation, autonomous
electric vehicles, personal transportation, and car sharing programs, all of
which will mean that lithium-ion battery technology will need to continue to
evolve in order to support these trends (Warner, 2015).

 

Today,
I see continued movement toward higher energy density chemistries. Some
companies that have historically used lower energy density lithium-iron
phosphate (LFP) chemistries are begin­ning to transition to higher energy
density lithium nickel manganese cobalt (NMC) chemistries. But the materials’
companies that manufacture these are also starting to introduce new
formulations with greater nickel content to improve the energy density. There
are some challenges that many cell manufacturers are still working to resolve,
including electrolyte formula­tion and temperature performance. These are
evolutionary changes to the current technologies that we will see in the market
place over the next several years.

 

In addition to the cathode develop­ment,
there is still a lot of work going on in the anode materials development. This
is falling in a couple of areas, with the greatest area focus being the develop­ment
of a silicon — or more accurately, a silicon-blended — anode. The past few
years have shown us some dramatic improvements in cycle life, increasing from
less than 100 cycles to some mate­rials that manufacturers claim are able to
achieve more than 1,000 cycles.

 

In addition to these trends, there is an
overriding concern that is almost univer­sal, and that is safety. Recent
lithium-ion battery failures in Samsung smart phones and last year’s hoverboard
fires have continued to bring battery safety to the forefront of the public’s
mind. Battery manufacturers are working hard to improve their technologies to
reduce the potential for safety-related failures. In some cases, some
manufacturers are working to transition to non-flammable electrolytes, while
others are moving toward the use of ceramic and other separators to offer
improved safety.

 

The final evolutionary change that I will
discuss is cost. The industry has seen costs come down at a very rapid pace
over the past 10 years as more applications have begun integrating
lithium-ion-based cells. With increasing volumes, we find that de­creasing
materials costs have a significant effect on costs. The same effect is true of
the battery manufacturers, with commit­ments coming from major OEMs that it
makes it much easier to drive costs lower. In the early days of the
large-format lithi­um-ion batteries, virtually all manufactur­ers had to
install capital because there were no manufacturing facilities in place. Today,
nearly 10 years after the successful launch of vehicles like the Chevrolet Volt
and Nissan Leaf, the costs of these factories are largely amortized. Finally, as
energy densities have increased, the cost per watt-hour (Wh) continues to
decrease. In fact, this last factor is one of the largest factors that impacts
the cost per Wh and is mainly being achieved through the transition to higher
nickel content cathodes, which drives the energy up.

Toyota_Concept

 

Honda_Concept

 

Chevy_Concept

Concept cars from Toyota, Honda, and Chevrolet will need new, and perhaps revolutionary, batteries.

Revolutionary changes

As I mentioned earlier, revolutionary
changes are those that will take longer to develop into commercial viability
and/ or may still be early in the development stage. In most of these cases, we
will not see these in large volumes for close to 10 years for large
applications such as vehicles. However, we may see some of these entering the
market for consumer electronics much earlier as the usage profiles are
generally much easier than in the automotive applications.

 

The first revolutionary technology is the
emergence of solid-state batteries. The solid-state battery uses a solid
electrolyte that is deposited over the cathode and then the anode is coated on
top of that. The two big benefits here are energy density and safety. The
solid-state battery has the potential to drive very high energy density into
very small battery space. And the use of solid electrolytes means that there is
no flammable material in the battery, so a thermal failure is, at the very
least, extremely unlikely, if not impossible, to occur. However, at the current
state of the technology, solid-state cells are limited to the mAh scale and are
mainly appli­cable for very small applications. We will see this technology
begin to take hold in places like medical devices and consumer electronics over
the next five years. As the technology matures and larger cells become
possible, we can envision a time when they begin to power vehicles and larger
applications, but that is still more than a few years away.

 

Another developing technology trend which
shows great promise is the lithium-sulfur batteries. Lithium-sulfur batteries
have the potential to offer very low costs due to the sulfur in place of the
high-cost nickel, cobalt, aluminum, and other rare earth metals used in current
lithium-ion cells. In addition to the low cost, they may offer energy densities
in the range of 500 Wh/kg. Current lithium-ion cells range from about 160 Wh/kg
up to about 220 Wh/kg, with the maximum limit for current technologies expected
to be about 300 Wh/kg. So it may very well be that lithium-sulfur cells will be
the replacements for current lith­ium-ion batteries. However, as of today,
there are only a handful of companies actively developing lithium-sulfur cells,
and none are commercially available. As long as there are no major hurdles that
occur, I would expect to see these cells beginning to emerge in product form in
about five years and between five to 10 years becoming the new standard.
 

Conclusion

How far can the current technology take us?
Well, that is still to be seen. But some scientists have pegged the current
lithi­um-ion chemistries top-end energy den­sity at somewhere near 300 Wh/kg.
Some of these evolutionary changes may get us there in the next five to 10
years. In fact, we can see some cells in the low- to mid- 200 Wh/kg range
today. So, 300 Wh/kg is not out of reach. But beyond that, we may need to
depend on some of these more revolutionary technologies to pick up after that.
I would expect to see solid-state batteries moving into the medical and
consumer spaces over the next five years. In the large application space, I
think the lithium-sulfur batteries could become the next major shift in
technology, but that is likely still more than 10 years out.

 

But there are also some technologies that
haven’t been looked at in a long time that are now beginning to re-emerge. One
such technology is the Edison Battery. Thomas Edison patented a nickel-based
battery back in 1901, which is being re-developed today for mod­ern
applications by several companies. And of course, there are a slew of other
technologies out there that are under development in many universities and
national laboratories around the world that I did not mention here. Perhaps one
or more of these will move into position to be the next “new thing.”

 

Dr. John Warner is the Chief Marketing Officer for Indianapolis-based
EnerDel and author of the book “The Handbook of Lithium-Ion Battery Pack
Design” (2015). Dr. Warner has been in the battery indus­try for almost eight
years with companies such as XALT Energy, Magna Steyr Battery Systems, and
Boston-Power. Prior to that, Dr. Warner spent 18 years in the automotive
industry, including 12 years with General Motors.