Maxwell Technologies and Tianjin Lishen Batteries to Develop and Market Hybrid Energy Storage Systems (HESS) Combining Ultracaps and Li-ion Batteries
Maxwell Technologies, Inc. and Tianjin Lishen Battery Joint-Stock Co., Ltd., (Lishen), China’s leading producer of rechargeable lithium-ion batteries, have formed an alliance through which they plan to manufacture and market novel hybrid energy storage system (HESS) products combining the companies’ respective ultracapacitor and li-ion battery technologies.
The companies have identified a number of initial target applications for the new products that leverage the complementary power-dense and energy-dense strengths respectively of double layer capacitor and li-ion battery technologies, ranging from quick-charge cordless tools to electric vehicles, and anticipate production and delivery of initial product samples in early 2008.
We believe that the products we envision will give end-users the best of both worlds in terms of the long cycle life, rapid charge/discharge characteristics and low temperature performance of ultracapacitors and the large energy storage capacity of lithium-ion batteries.
We also plan to move some of our BOOSTCAP product assembly to Lishen in order to leverage our joint process engineering capabilities, and Lishen will conduct development and qualification testing on battery electrode material produced through Maxwell’s proprietary dry process, so we see this as a deep and strategically important alliance for both companies.—David Schramm, Maxwell’s President and CEO
|Active and Passive Parallel HESS configurations. Click to enlarge.|
At the 2007 AABC conference, John Miller from Maxwell suggested in his presentation that a hybrid Li-ion/ultracapacitor storage solution applied to an extended range electric vehicle (EREV) such as the Chevrolet Volt could extend the State of Charge operating window from the 30%-80% range offered by lithium-ion batteries alone to a 20% to more than 90% range.
Earlier this year, Maxwell announced a collaboration with Argonne National Laboratory on a research project to assemble and evaluate an integrated ultracapacitor/lithium-ion battery energy storage system for hybrid-electric and plug-in hybrid vehicles. (Earlier post.)
Argonne and Maxwell agreed on an active parallel system configuration that will combine a standard lithium-ion plug-in hybrid battery with a string of 112 of Maxwell’s BOOSTCAP BCAP0650 P270 650-farad ultracapacitor cells, along with appropriate power electronics and cooling and safety-related features.
An active parallel configuration controls the ultracapacitor energy flows via an energy management strategy with a power electronics converter to minimize battery cycling. A passive parallel HESS has the ultracapacitor responding immediately to pulse power load, with the battery branch of the system responding more slowly, then recharging the ultracapacitor.
Lishen currently produces more than 130 million li-ion batteries annually in its 860,000 square-foot production facility, located in Tianjin, China, supplying rechargeable batteries to multiple cellular telephone manufacturers, including Motorola and Samsung, and numerous consumer electronics manufacturers, including Apple for devices such as MP3 players.