A battery pack, comprising: a battery pack housing defining a first interior space and a second interior space, the battery pack housing having a base portion and an upper cover, said base portion includes a bottom wall and four side walls (92,94,96,96), wherein a first side wall includes an inlet aperture communicating with the first interior space, and a second side wall includes an outlet aperture communicating with the second interior space; a battery module being disposed in the first interior space and having a heat exchanger configured to allow air entering the first interior space through the inlet aperture to pass therethrough and at least one battery cell disposed against the heat exchanger, wherein the battery module has first and second end plates (230, 232) extending past internal battery cells (150-170; 180-200) disposed therebetween, the first end plate extends substantially parallel to a longitudinal axis of the battery module and has a first end portion extending longitudinally past a first end of the internal battery cells toward the inlet aperture and contacting the first wall above the inlet aperture, and the second end plate extends substantially parallel to the longitudinal axis of the battery module and has a first end portion extending longitudinally past the first end of each of the battery cells toward the inlet aperture and contacting the first wall below the inlet aperture; a DC-DC voltage converter being disposed in the second interior space such that the air flowing from the heat exchanger toward the outlet aperture cools the DC-DC voltage converter; an electric fan adapted to urge the air to flow from the inlet aperture through the first and second interior spaces (76, 78) to the outlet aperture of the battery pack housing; a first temperature sensor being disposed in the first interior space, the first temperature sensor adapted to generate a first signal indicative of a first temperature level of the battery cell; a second temperature sensor being disposed in the second interior space, the second temperature sensor adapted to generate a second signal indicative of a second temperature level of the DC-DC voltage converter; a microprocessor operably coupled to the first and second temperature sensors (48, 50) such that the microprocessor receives the first and second signals, respectively, the microprocessor further operably coupled to the electric fan; the microprocessor being configured to determine a first desired operational speed value and a second desired operational speed value of the electric fan based on the first temperature level and the second temperature level, respectively, and to generate a control signal that induces the electric fan to operate at an operational speed corresponding to a greater operational speed value between the first and second operational speed values. a battery pack housing defining a first interior space and a second interior space, the battery pack housing having a base portion and an upper cover, said base portion includes a bottom wall and four side walls (92,94,96,96), wherein a first side wall includes an inlet aperture communicating with the first interior space, and a second side wall includes an outlet aperture communicating with the second interior space; a battery module being disposed in the first interior space and having a heat exchanger configured to allow air entering the first interior space through the inlet aperture to pass therethrough and at least one battery cell disposed against the heat exchanger, wherein the battery module has first and second end plates (230, 232) extending past internal battery cells (150-170; 180-200) disposed therebetween, the first end plate extends substantially parallel to a longitudinal axis of the battery module and has a first end portion extending longitudinally past a first end of the internal battery cells toward the inlet aperture and contacting the first wall above the inlet aperture, and the second end plate extends substantially parallel to the longitudinal axis of the battery module and has a first end portion extending longitudinally past the first end of each of the battery cells toward the inlet aperture and contacting the first wall below the inlet aperture; a DC-DC voltage converter being disposed in the second interior space such that the air flowing from the heat exchanger toward the outlet aperture cools the DC-DC voltage converter; an electric fan adapted to urge the air to flow from the inlet aperture through the first and second interior spaces (76, 78) to the outlet aperture of the battery pack housing; a first temperature sensor being disposed in the first interior space, the first temperature sensor adapted to generate a first signal indicative of a first temperature level of the battery cell; a second temperature sensor being disposed in the second interior space, the second temperature sensor adapted to generate a second signal indicative of a second temperature level of the DC-DC voltage converter; a microprocessor operably coupled to the first and second temperature sensors (48, 50) such that the microprocessor receives the first and second signals, respectively, the microprocessor further operably coupled to the electric fan; the microprocessor being configured to determine a first desired operational speed value and a second desired operational speed value of the electric fan based on the first temperature level and the second temperature level, respectively, and to generate a control signal that induces the electric fan to operate at an operational speed corresponding to a greater operational speed value between the first and second operational speed values.