
                ECD OVONICS' BATTERY SUBSIDIARY EXPANDS CONSUMER
                          BATTERY RELATIONSHIP WITH BYD

Rochester Hills, Mich., May 11, 2005 -- Energy Conversion Devices, Inc. (ECD
Ovonics) (NASDAQ:ENER) announced today that its subsidiary, Ovonic Battery
Company, Inc. (Ovonic Battery), has expanded its existing consumer battery
license agreement for its proprietary nickel metal hydride (NiMH) battery
technology with BYD Company Limited (BYD) of the People's Republic of China.
Under the consumer battery license grant, BYD has a royalty-bearing,
nonexclusive right to make, use and sell consumer NiMH batteries for
nonpropulsion applications.

In a statement, Robert C. Stempel, Chairman and CEO of ECD Ovonics and Chairman
of Ovonic Battery, said, "We are pleased to grant BYD access to recent Ovonic
patents and advanced technology. We have watched BYD's rapid growth in nickel
metal hydride over the last few years and, as part of our strategy to
participate in the growing Chinese economy, we hope to assist their efforts in
developing premium performance nickel metal hydride products."

About ECD Ovonics
ECD Ovonics is the leader in the synthesis of new materials and the development
of advanced production technology and innovative products. It has pioneered and
developed enabling technologies leading to new products and production processes
based on amorphous, disordered and related materials, with an emphasis on
advanced information technologies and alternative energy, including
photovoltaics, fuel cells, consumer hydride batteries and hydride storage
materials capable of storing hydrogen in the solid state for use as a feedstock
for fuel cells or internal combustion engines or as an enhancement or
replacement for any type of hydrocarbon fuel. ECD Ovonics designs and builds
manufacturing machinery that incorporates its proprietary production processes,
maintains ongoing research and


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development programs to continually improve its products, and develops new
applications for its technologies. ECD Ovonics holds the basic patents in its
fields. ECD Ovonics' website address is http://www.ovonic.com.

About BYD Co. Ltd.
Established in 1995, BYD Company Ltd. manufactures a broad line of NiCd, NiMH
and Li-Ion battery products. Located in Shenzhen, Guandong, BYD has grown
rapidly and has become one of China's largest manufacturers of NiCd and NiMH
batteries, with worldwide sales of these products including within the PRC,
U.S., Japan and Europe. BYD is a joint stock limited company incorporated in the
People's Republic of China. BYD's website address is http://www.byd.com.cn.


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This release may contain forward-looking statements within the meaning of the
Safe Harbor Provisions of the Private Securities Litigation Reform Act of 1995.
Such forward-looking statements are based on assumptions which ECD Ovonics, as
of the date of this release, believes to be reasonable and appropriate. ECD
Ovonics cautions, however, that the actual facts and conditions that may exist
in the future could vary materially from the assumed facts and conditions upon
which such forward-looking statements are based.

Contacts:
Ghazaleh Koefod, Investor Relations
Dick Thompson, Media Relations
Energy Conversion Devices, Inc.
248.293.0440


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