Laser directed energy weapons require significantly more power during target engagement than available 5 times) from the platform's electrical system. Therefore, an energy storage subsystem that charges from the platform's available power can be used to supply the very high power level required when firing the laser. Typical laser engagement duration is from one to sixty seconds. Lithium ion (Li-Ion) batteries provide a practical solution since they have high energy density and are capable of providing the very high discharge rates required at high efficiency. Instead of utilizing a large monolithic battery, a distributed battery approach consisting of a number (e.g., 23) of identical battery modules provides many advantages, including flexibility in packaging on the platform, as well as growth potential for higher power lasers by adding more modules. Each energy storage module must typically provide 10 kW of power to it's associated fiber laser module. Even though lithium ion chemistry has the highest efficiency, each module will dissipate about 800 watts during laser activation, requiring a practical thermal management solution.