Boston-Power, a Massachusetts advanced battery company, makes lithium-ion batteries that charge faster and last longer than conventional lithium-ion batteries.Â
Last month, Boston-Power announced that Hewlett-Packard (HP) would be its first customer and would offer its Sonata battery as an upgrade option in select HP notebook PCs in early 2009.  (see the greentechmedia piece here and the New York Times article here)
Boston-Power owns several U.S. patent applications covering its battery technology, including U.S. Application Pub. Nos. 2008/0008928 (‘928 application) and 2008/0008933 (‘933 application).
Conventional lithium-ion batteries have a cathode (an electrode that circulates electrons) made of lithium cobalt. The ‘933 application is directed to a blend of two or more different types of cathode materials in the positive electrode which enables manufacturing of larger cells than conventional lithium-ion batteries that use lithium cobalt alone.Â
According to the ‘933 application, increasing capacity through these larger cells is a better solution than increasing the number of cells, which raises the probability of over-charge or over-discharge.
The ‘928 application is directed to a battery integrated with a current interrupt device (CID). When lithium-ion batteries are improperly charged, exposed to high temperatures, or are short circuited, they may produce gas, and the pressure increase can be dangerous.Â
CIDs protect against excessive internal pressure increases in batteries by interrupting the current path when pressure increases. However, according to the ‘928 application, CIDs incorporated within batteries take a lot of space and limit battery capacity.
The invention of the ‘928 application is a battery in which at least a portion of the CID (28) may be located external to the battery can (21) because the CID is in electrical communication with the battery can. Specifically, at least one of the cell casing (22) and the lid (24) of the battery can (21) are in electrical communication with the second electrode (14) of the battery (10) through the CID (28).
Boston-Power’s technology provides significant advantages over the competition. According to the greentech media article, Boston-Power’s batteries take a half hour to charge to 80% capacity, instead of 2 hours for an ordinary battery.Â
Also, the batteries can last about 1,000 charging cycles (i.e. three years), before the charging capacity becomes substantially diminished, whereas conventional lithium-ion batteries go about 300 cycles or fewer. As a result, HP will provide a 3-year warranty with the Sonata battery.