cramento, California

By

The
Year 2000 Battery Technology Advisory Panel

Menahem
Anderman

Fritz R. Kalhammer

Donald MacArthur

DISCLAIMER

The
findings and conclusions in this report are those of the authors and
not necessarily those of the State of California Air Resources Board.
The mention of commercial products in connection with the material presented
herein is not to be construed as actual or implied endorsement of such
products.

When the California Air Resources Board began to consider battery-powered
EVs as a potentially major strategy to reduce vehicle emissions and
improve air quality, it did so with the view that the broadest market
would be served by electric vehicles with advanced batteries, and it
structured its ZEV credit mechanisms to encourage the development and
deployment of EVs with such batteries. Consistent with this view, the
Air Resources Board defined the scope of work for the first Battery
Technical Advisory Panel study to focus on advanced batteries.

Five years after the modification of the 1991 Zero Emission Vehicle
regulation, and after a period of intensive effort to develop, deploy
and evaluate advanced electric vehicles, one key remaining question
is whether batteries can be available in 2003 that would make electric
vehicles acceptable to a large number of owners and operators of automobiles.
The answer to this question is an important input to the California
Air Resources Board's year 2000 Biennial ZEV regulation review. The
authors of this report were asked to assist ARB in developing an answer,
working together as a new Battery Technical Advisory Panel (BTAP 2000).

The Panel concentrated its investigation on candidate EV-battery technologies
that promise major performance gains over lead-acid batteries, appear
to have some prospects for meeting EV-battery cost targets, and are
now available from low-volume production lines or, at least, laboratory
pilot facilities. In the view of the Panel, other types of advanced
batteries not meeting these criteria are highly unlikely to be introduced
commercially within the next 5-7 years. While the focus of BTAP 2000
like the first battery panel was to be on advanced batteries because
of their basic promise for superior performance and range, ARB asked
the Panel to also briefly review the lead-acid battery technologies
used in some of the EVs deployed in California. This request recognized
that EVs with lead-acid batteries were introduced in the 1990s by several
major automobile manufacturers beginning with General Motors EV1, and
that EVs equipped with recently developed lead-acid batteries were performing
significantly better than earlier EVs.

The Panels approach was similar to that of the
1995 BTAP: visits to the leading developers of advanced batteries and
to major automobile manufacturers engaged in electric-vehicle development,
EV deployment, and in the evaluation of EV batteries; follow-on discussions
of the Panels observations with these organizations; Panel-internal
critical review of information and development of conclusions; and preparation
of this report. To assist the Panel members with the development of
judgment and perspective, they were given business-confidential technical
and strategic information by nearly all of the Panels information sources.
This report, however, contains unrestricted material only. The Panels
findings and conclusions are as follows.

The improved lead-acid EV batteries used in some
of the EVs operating in California today give these vehicles better
performance than previous generations of lead acid batteries. However,
even these batteries remain handicapped by the low specific energy that
is characteristic of all lead-acid batteries. If EV trucks or representative
4-5 passenger EVs could be equipped with lead-acid batteries of sufficient
capacity to provide a practical range of 75-100 miles on a single charge,
batteries would represent 50% or more of the total vehicle weight. The
specific costs of these batteries produced in volumes of 10,000-25,000
packs per year are projected to be between $100/kWh and $150/kWh, about 
30-50% of the cost projected for advanced batteries produced in comparable
volume. On the other hand, the life of lead-acid batteries remains a
serious concern because the high cost of battery replacement might well
offset the advantage of lower first costs.

Nickel-metal hydride (NiMH) batteries, employed in more than 1000
vehicles in California, have demonstrated promise to meet the power
and endurance requirements for electric-vehicle (EV) propulsion. Bench
tests and recent technology improvements in charging efficiency and
cycle life at elevated temperature indicate that NiMH batteries have
realistic potential to last the life of an EV, or at least ten years
and 100,000 vehicle miles. Several battery companies now have limited
production capabilities for NiMH EV batteries, and plant commitments
in 2000 could result in establishment of manufacturing capacities sufficient
to produce the quantities of batteries required under the current ZEV
regulation for 2003. Current NiMH EV-battery modules have specific energies
of 65 to 70Wh/kg, comparable to the technologies of several years agoreported
in the BTAP 1995 report (1)and major increases are unlikely. If NiMH
battery weight is limited to an acceptable fraction of EV total weight, the range of a typical
4/5-passenger EV in real-world driving appears limited to approximately
75 to 100 miles on a single charge.

Despite extensive cost reduction efforts by the leading NiMH EV-battery
developers, NiMH battery cost remains a large obstacle to the commercialization
of NiMH-powered EVs in the near term. From the cost projections of manufacturers
and some carmakers, battery module specific costs of at least $350/kWh,
$300/kWh and $225-250/kWh can be estimated for production volumes of
about 10k, 20k and 100k battery packs per year, respectively. To the
module costs, at least $1,200 per battery pack (perhaps half of that
sum in true mass production) has to be added for the other major components
of a complete EV-battery, which include the required electrical and
thermal management systems. On that basis, and consistent with the Panels
estimates, NiMH batteries for the EV types now deployed in California
would cost EV manufacturers between  $9,500 and $13,000 in the
approximate quantities (10k-20k packs per year) required to implement
the year 2003 ZEV regulation, and approximately $7,000 to $9,000 at
production levels exceeding one hundred thousand packs per year.

Lithium-ion EV batteries
are showing good performance and, up to now, high reliability and complete
safety in a limited number of EVs. However, durability test data obtained
in all major lithium-ion EV-battery development programs indicate that
battery operating life is typically only 2-4 years at present. Li Ion
EV batteries exhibit various degrees of sensitivity when subject to
some of the abuse tests intended to simulate battery behavior and safety
under high mechanical, thermal or electrical stresses. Resolution of
these issues, the production of pilot batteries and their in-vehicle
evaluation, and fleet testing of prototype Li Ion batteries meeting
all critical requirements for EV application are likely to require at
least three to four years. Another two years will be required to establish
a production plant, verify the product, and scale up to commercial production.
Based on several (albeit not all) of the cost estimates provided by
developers and on the Panels own estimates, these batteries will be
significantly more expensive than NiMH batteries at a production volume
of around 10,000 packs per year. Even in much larger production volumes,
Li Ion EV batteries will cost less than NiMH only if substantially less
expensive materials become available, and after manufacturing technologies
combining high levels of automation, precision and speed have been developed.

Lithium-metal polymer EV batteries are being developed in two programs
aimed at technologies that might cost $200/kWh or less in volume production.
However, these technologies have not yet reached key technical targets,
including most notably cycle life, and they are in the pre-prototype
cell stage of development. It is unlikely that the steps required to
achieve commercial availability of Li Polymer batteries meeting the
performance and life requirements, as well as the cost goals for EV
propulsion, can be completed in less t