[Texgreen] Plug-in electric cars

[Roger Baker]

On Mar 3, 2007, at 1:11 PM, Alfred Molison wrote:

> I assume you're in favor of plug in electric or hybrid cars.  I =20
> agree with you that "Problem Solved" on the battery situation is a =20
> little too simple once I started digging into it.  The problem is =20
> only solved by degrees.
>
> My friend, Vickie, drew a graph showing that the high end batteries =20=

> had a constant utility until the end of their life when they have a =20=

> drastic drop off in energy and rechargeability.  Low end batteries =20
> had a longer and more constant utility than the high end batteries. =20=

> But during their lifetime the batteries were not nearly as easy to =20
> recharge and stay high energy as the high end batteries.
>
> If you ignore something minor, like cost, then high end batteries =20
> like lithium ion are the best as far as easy availability, =20
> recharging and maximum output for a two year period.  But if you do =20=

> take into account cost, then a $250,000, or more, bill every two =20
> years makes lithium ion batteries become annoying.
>
> How about nickel metal hydrides?  http://en.wikipedia.org/wiki/=20
> Nickel_metal_hydride  maybe they're the middle range batteries.  =20
> They're used in the Toyota Prius, the Honda Civic Hybrid and the =20
> Honda Insight.  They were used in the Generl Motors Ev1. (Who =20
> Killed the Electric Car).  At around $2500 per battery, (please =20
> call a dealership auto parts store to check the price) my thinking =20
> is that it's possible to rig up three of them in a car and have a =20
> viable 100% electric vehicle, if that's what you want.  I don't =20
> know how long they last.  But they're certainly cheaper than an =20
> array of lithium ion computer batteries.
>
> Next is plain old lead acid batteries.  Easily available, cheap, =20
> poisonous, potentially explosive but apparently endlessly =20
> recyclable.  The technology is, what, over 110 years old for =20
> automobiles? On the internet I discovered hundreds of used cars =20
> that had been converted to electric vehicles with lead =20
> batteries.    I suspect that most of the owners have an extra car =20
> for long distance travel.  But for in town work, errands or =20
> shopping they must be reliable enough.
>
> Alfred Molison

Oil is peaking now probably, but it will take more than a decade to =20
ramp up electric vehicle production, and batteries are still a major =20
problem for typical commuting distances; there are no cheap batteries =20=

that will go as far as we are used to going (and the prospect is to =20
use MOSTLY electricity based on coal-burning power to replace the =20
gasoline power).

Here is some battery optimism at the EV world site:

<http://www.evworld.com/article.cfm?storyid=3D1198>

But following is probably a more realistic point of view. The truth =20
is probably that we in the USA are going to be forced to stop driving =20=

so much, but we'll perceive it through increasing cost; the following =20=

snips are from some excellent expert testimony to Congress at the =20
link below.

"...conventional HEV technology is the only one mature enough for its =20=

market growth to have an impact on the nation's energy usage in the =20
next 10 years. Pending significant improvements in battery =20
technology, plug-in hybrids could possibly start making an impact in =20
about 10 years..."

In other words, plug-in hybrids could start making a difference in =20
ABOUT TEN YEARS, whereas it appears that oil is peaking now to be =20
followed soon by higher prices (see the recent Matt Simmons press =20
conference on Bloomberg;  http://www.theoildrum.com/node/=20
2239#comments ). The question is what do we do until then? (The =20
problem is now largely in the lithium battery technology.)

Apparently until then, its going to be the gradual if anxious =20
substitution of smaller cars and conventional hybrids for the aging =20
guzzlers. -- Roger

            *********************************************************

http://www.evworld.com/view.cfm?page=3Darticle&storyid=3D1184

"... Currently, essentially all hybrids with moderate to significant =20
powertrain hybridization employ a NiMH battery as the main electrical-=20=

energy storage device. NiMH batteries are a reliable power source for =20=

hybrid cars; their manufacturing base is expanding, and field results =20=

suggest long life. However, NiMH batteries are not an ideal energy-=20
storage device for hybrid cars. Their limitations include moderate =20
energy conversion efficiency, which translates to some energy loss =20
and significant heat production in normal usage, reduced life with =20
high depth-of-discharge (DOD) cycling, and unsatisfactory performance =20=

at high and low temperatures. NiMH battery packs for HEVs are priced =20
at $900 to $1500 per kWh, which brings the price of today's pack to =20
between $600 and $3,000 per vehicle. The 2006 NiMH battery market for =20=

HEVs is estimated at $600 million. Although NiMH is currently the =20
most economical (and only proven) power source for the application, =20
it has limited potential for cost reduction as production volume =20
further increases, particularly in light of recent substantially =20
higher nickel prices=97nickel, in several metallic forms and compounds, =20=

being the battery's main component.

Lithium-ion batteries offer higher power and energy per unit weight =20
and volume, and better charge efficiency than NiMH batteries. Thus, =20
if they can maintain performance over life, smaller and lighter =20
batteries can be used in given applications. These attributes allowed =20=

them to capture a major part of the portable rechargeable battery =20
market=97which requires a battery life of only 2 to 3 years=97within a =20=

few years of their introduction, and to generate global sales =20
estimated at $5 billion in 2006. Nevertheless, the reliability of =20
lithium-ion technology for automotive applications is not proven=97=20
unfriendly failure modes, for example, are a concern=97and its current =20=

cost is higher than that of NiMH.

Over the last five years, most automakers have started to evaluate =20
the suitability of lithium-ion batteries for HEV applications, and =20
two Japanese automakers even embarked on sizeable in-house lithium-=20
ion battery development projects. In the U.S., significant progress =20
has been made under the auspices of the U.S. Advanced Battery =20
Consortium, a collaborative effort between the U.S. Department of =20
Energy, the auto industry, and battery developers. Sometime in the =20
future, lithium-ion technology is likely to become the battery of =20
choice for most hybrid applications, although the recent reliability =20
problems experienced with lithium-ion batteries in portable devices =20
may delay its acceptance. Nevertheless, following extensive system-=20
verification tests, lithium-ion batteries are still expected to enter =20=

the HEV market in 2 to 3 years, and their use to grow thereafter, =20
provided no major negative surprises arise.

Lithium-ion HEV batteries are likely to initially carry a slightly =20
higher price than NiMH batteries but price parity is expected to =20
occur as volume reaches that of the NiMH business. Moreover, they =20
hold better potential for further cost reduction through improvements =20=

in technology and economies of scale.

It is useful to note here that world investment in lithium-ion =20
battery technology R&D continues to increase and is estimated at well =20=

over $1 billion annually, which is several times the total investment =20=

in R&D for all other battery technologies combined. We estimate that =20
there are over a hundred materials, chemicals, and battery companies, =20=

several thousand academic researchers, and hundreds of scientists in =20
government-owned laboratories involved in various aspect of lithium-=20
ion battery technology R&D.

Plug-in Hybrids and their Battery Requirements
While the development of plug-in hybrid vehicles by car manufacturers =20=

is still at an early stage, industry experience with all-electric =20
vehicles on the one hand, and with conventional hybrid electric =20
vehicles on the other, is sufficient to provide general guidelines =20
for their battery requirements.

In an all-electric vehicle, the battery is the only power source on =20
board and is used in the so-called 'charge-depletion' mode, i.e. the =20
battery is fully charged externally (typically at night) and is =20
depleted at a steady rate during driving. In this case, the battery =20
usually provides only one charge-discharge cycle per day, with the =20
depth of discharge depending on the battery capacity and the driving =20
range. In a conventional HEV, the battery is operated in the so =20
called 'charge-sustaining' mode, i.e. the battery is charged and =20
discharged on board around an intermediate state of charge, typically =20=

about half-way between fully charged and fully discharged. In this =20
application, the battery may be called upon to provide hundreds or =20
more shallow cycles per day, never approaching the fullycharged or =20
fully-discharged state.

In a classical plug-in HEV, the battery is fully charged externally, =20
typically on a daily basis. When the vehicle is driven after =20
charging, the battery operates in the chargedepletion mode, just like =20=

an EV battery. Later, as the battery reaches some predetermined low =20
state of charge, the vehicle switches to a charge-sustaining mode, in =20=

which the battery will be used like that of a conventional HEV. =20
Because of these dual functions the battery's usage profile in a plug-=20=

in HEV is considerably more demanding than that of either a full EV =20
battery or a conventional HEV battery, with obvious negative =20
implications for battery longevity.

For a plug-in hybrid electric vehicle the requirement that dictates =20
its battery capacity is the range of electric drive for which the =20
vehicle is designed (Note: some 'plug-in' architectures do not =20
emphasize electric drive, but to keep this discussion simple, we will =20=

consider an architecture that requires it). Depending on its weight, =20
aerodynamic design, and driving pattern, a typical mid-size vehicle =20
with an electric motor will utilize 0.2 to 0.4 kWh of energy per mile =20=

driven, which means that 1 kWh of energy will propel a car for =20
between 2.5 and 5 miles. For the sake of simplicity we will assume a =20
3-4 mile range per kWh of used energy. Thus, for a 20-mile range of =20
electric drive, the car will use 5-7 kWh of energy. However, since =20
the duty cycle of the application is considerably more severe than =20
that of HEV or EV batteries, to even stand a chance of meeting life =20
requirements using today's technology it will be necessary to design =20
a battery with 1.5 to 2 times the energy capacity required for the =20
drive. In other words, a plug-in vehicle with a 20-mile range will =20
require a battery with a rated energy capacity of 8 to 14 kWh. Again =20
for the sake of simplicity we will assume a battery capacity of 10kWh =20=

for the rest of the analysis.

Since the average capacity of today's strong hybrid batteries is 1.7 =20
kWh, the above calculation shows that the 20-mile plug-in battery =20
will need an energy capacity 6 times higher than that of today's =20
average HEV battery. This brings out several significant issues:

# The plug-in battery will be about 3 to 5 times the size of today's =20
conventional HEV batteries, essentially filling the cargo space of an =20=

average sedan.

# The weight of this battery will add 200 to 300 lb. to that of the =20
car, which will adversely affect vehicle performance and efficiency.

# If the plug-in battery vehicle contains a lithium-ion battery, =20
which is to be given a full charge every night in a residential =20
garage, there is a much more serious concern about hazardous failure =20
than with the smaller batteries of conventional HEVs, which are =20
always kept at an intermediate state of charge.

# The cost of this plug-in battery (at pack level) to carmakers, =20
using present technology, will be 3 to 5 times the average cost of =20
today's HEV batteries, i.e. around $5,000 to $7,000 per pack.

# The life of either battery technology, NiMH or lithium ion, in the =20
plug-in application is not known. There is a significant risk that =20
its life will be shorter than that of conventional hybrid-car batteries.

Unfortunately, items 4) and 5) above compound each other, making the =20
cost of replacing the battery prohibitive (should the battery need to =20=

be replaced during the life of the car). It is our opinion that wide-=20
spread commercialization of plug-in hybrids with a range of 20 miles =20
or more is only possible if there is notable improvement in battery =20
performance, proven battery longevity and reliability in well-=20
designed lab and field tests=97which, in combination, are likely to =20
require 3 to 5 years=97along with a significant reduction in battery =
cost.

Government Initiatives
U.S. government initiatives to promote the growth of the HEV market =20
through subsidies, incentives, taxation, or tighter fuel-efficiency =20
regulations will all encourage further industry investment in fuel-=20
efficient transportation. Because batteries are critical to the =20
potential success of the hybrid-vehicle business, direct investment =20
in battery technology is also likely to advance the technology and in =20=

turn the viability of HEVs. Lithium-ion battery chemistry is clearly =20
the most promising in terms of supporting future conventional HEVs as =20=

well as in approaching the target requirements of plug-in HEVs. While =20=

lithiumion technology will continue to evolve as a consequence of the =20=

large worldwide investment in this technology, U.S. Government =20
regulations that support the growth of the HEV market and/or its =20
funding of lithium-ion battery development would certainly accelerate =20=

progress. In our opinion, such enhanced progress could allow lithium-=20
ion battery technology to enter the conventional U.S. HEV market =20
earlier than without it, thereby increasing the attractiveness of =20
these vehicles and stimulating their market growth. In the longer term=20=

=97perhaps in about 10 years=97accelerated progress may gradually close =20=

the gap between the targeted battery requirements for plug-in HEV and =20=

the state and cost of battery technology, thus facilitating the =20
introduction of plug-in hybrid vehicles as well..."

It also is our opinion that as far as electric drive and electric-=20
assist drive technology is concerned, conventional HEV technology is =20
the only one mature enough for its market growth to have an impact on =20=

the nation's energy usage in the next 10 years. Pending significant =20
improvements in battery technology, plug-in hybrids could possibly =20
start making an impact in about 10 years, while vehicles powered by =20
fuel cells are unlikely to enter high-volume production in less than =20
20 years...