TIAX Issued U.S. Patent for Next-Generation HEV Battery Technology

June 20, 2007 by Jeff Shepard

TIAX announced that it has been issued one patent and received one notice of allowance by the United States Patent and Trademark Office for its Cel-X™ battery control technology. Cel-X is claimed to be a low-cost, high-performance system that improves the safety, capacity, and pack life of lithium-ion batteries through a non-dissipative approach to regulating state of charge.

Compared to the nickel-metal hydride batteries currently used in hybrid electric vehicles (HEVs), lithium-ion batteries have higher power capability and longer runtime in packs that are smaller, lighter, and more cost effective, making them suitable candidates for use in next-generation HEVs and plug-in hybrid electric vehicles (PHEVs). It is estimated that PHEVs using lithium-ion batteries could achieve fuel efficiency of 100 mpg or more, reducing the use of petroleum and potentially reducing greenhouse gas emissions.

Despite the advantages of lithium-ion, technical challenges have kept these batteries from being used in automotive and other large-format battery applications. These applications depend on large battery packs made of multiple cells connected in series to achieve the high voltages required. A key hurdle has been the complexity and extra cost of effectively regulating the state of charge across these series of connected cells.

"We’re very proud to be advancing a technology that could significantly accelerate the presence of HEVs and PHEVs on the market," said TIAX CEO and founder, Kenan Sahin. "Our solution to cell balancing enables exciting new hybrid models that deliver the performance, safety, low cost, durability, and fuel efficiency that consumers are demanding."

Over the life of a battery pack, imbalances that hinder battery performance, shorten life, and increase warranty costs and safety risks develop across cells. In traditional dissipative approaches to cell balancing, the battery pack capacity is limited by the lowest capacity cell. This limits the useful life of a battery pack and translates into high warranty costs and customer complaints in applications, such as cars and trucks, where lengthy performance lifetimes are required.

The company claims that Cel-X provides maximum possible energy while keeping cells in balance, protecting lithium-ion battery packs from the detrimental effects of unbalanced distribution of charge across cells. The result is said to be a battery pack with longer life, increased capacity and improved safety.