Marketed as the Dynamic Power Resources (DPR) product line, XP’s systems combine energy storage and control capabilities in a modular approach that provides flexibility in size for various scale grid and off-grid applications.
XP owns at least one U.S. patent and several pending patent applications relating to its technology, which aims to efficiently equalize batteries, i.e., reduce the gap between the weakest and strongest cell in a battery pack.
At least two of XP’s patent applications – Publication Nos. 2008/0088276 (’276 Application) and 2009/0134718 (’718 Application) – are directed to battery packs having a uniform or optimum DC environment for every cell in the battery pack.
U.S. Patent No. 7,808,131 (’131 Patent) also relates to a battery pack connection scheme that achieves a synchronized DC environment for the cells.
The ’276 Application describes a battery pack (100) having batteries (101, 102), a positive terminal (106), a negative terminal (108), and cables (111, 112, 121, 122) connecting the batteries to the terminals in a parallel fashion.
The connections form uniform parallel conductive paths, as shown in the circuit diagram below. In particular, the first cable (111), first battery (101), and second cable (112) form a parallel circuit with the third cable (121), second battery (102), and fourth cable (122).
The circuit branch consisting of cable (111), battery (101) and cable (112) is similar and preferably identical to the branch consisting of cable (121), battery (102) and cable (122). More particularly, resistance, inductance, and capacitance are modeled for each cable and those values for cable (112) are very close to corresponding values for cable (122).
According to the ’276 and ’718 Applications, this configuration makes the voltage and current nearly uniform throughout the cells:
A battery pack connection scheme is shown that provides a synchronized DC environment for every cell in the pack, such that every cell in the same or similar voltage level in the pack sees an identical, or very similar, voltage and current environment.
XP’s battery technology has impressed at least one major utility as the company was selected by Duke Energy to provide what would be the largest (36 MW) energy storage system linked to a wind farm at a planned wind plant in west Texas.
Eric Lane is a patent attorney at Luce, Forward, Hamilton & Scripps in San Diego and the author of Green Patent Blog. Mr. Lane can be reached at firstname.lastname@example.org.