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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.


Harvey D

Very interesting from an application and production point of view. This combination could supply the instant (quick) discharge/charge + high energy required for PHEVs and BEVs.

Tianjin Lishen already has (or could quickly have) the facilities required to produce large (HESS) quantities at a very competitive price.

Vehicles (PHEVs and BEVs) manufacturers may have the power packs they have been waiting for within 1 or 2 years.

Will the first power pack be ready for 2008 Olympics?

Rafael Seidl

Ultracap/battery combos make a lot of sense but they are tricky to implement. The voltage across a battery is nearly constant with SOC but that across a capacitor is just 1/4 of rated tension when its down to 1/16th of rated charge.

In a passive configuration as shown, the capacitor would be forced to the voltage of the battery. It's not clear to me how it could change its state of charge at all.

With a power converter, the voltage issue can be overcome, though a factor of 4 is not easy to achieve in a single stage.

Harvey D


It seems that the coexistence problems have already been solved.

On-going lower cost mass production of various size units seems to be the main objective of this Joint Venture.

In principle, Tianjin Lishen could produce a few million units a year in a rather short time.

However, you can be sure that worldwide competition will come into play and other alliances will share this lucrative market. That would be very positive for future HEVs, PHEVs and BEVs.

Max Reid

Excellent, Hybrids came to the market and excelled.
Pretty soon, Li-Ion & Ultracaps will come and revolutionize.


Finally someone is using their noggin. I think this solution should also decrease the strain on the battery thereby greatly increasing it's lifespan.


I don't know what you are trying to say Harvey D, or at least you are not saying it too clearly. First, the ultracap will have linear voltage discharge with a 'constant current' load. Further, you can utilize 75% of the ultracaps energy between rated voltage (a.k.a. working voltage) and 1/2 rated voltage.

Otherwise, you pose a good question about how a direct parallel connection can better the batteries energy draw situation. Although, it is true that it can, the explanation is not trivial, and the point is moot, as Maxwell and Lishen are combining the systems through a converter.

Finally, a factor of 4 is not too difficult to achieve with a power converter, although at the hybrid vehicle power levels, it is not a trivial design either. Nonetheless, it is definitely plausible.


Sorry, the above comment should have been directed to Rafael,... I am new to posting here, so I misinterpreted who wrote the comment I was referring to. My apology Harvey D.

richard schumacher

Rafael, the passive parallel configuration uses the fast response (that is, high dis/charge rate) of the cap to compensate for the slow response (that is, relatively low dis/charge rate) of the battery, so the combination has a greater power density than does a battery alone. As you noted the active approach allows the cap and battery to have different voltages, which increases the useable energy density of the cap.

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