Described are techniques for improving the functionality of a computing device by regulating the temperature of an energy storage device used to power the computing device. A housing that encloses the energy storage device may include a first portion having a thermal conductivity that exceeds that of a second portion. The first portion may be configured to contact or be positioned proximate to a user's body or other heat-producing object during use. Heat from the user's body or other object may be conducted through the first portion of the housing toward the energy storage device. The less-conductive second portion of the housing may reduce the rate at which heat from the energy storage device is transmitted into the ambient environment. As a result, the temperature of the energy storage device may increase, improving the performance thereof.