A two-dimensional, transient heat-transfer model for different methods of heat dissipation is used to simulate the temperature distribution in lithium-ion batteries. The experimental and simulation results show that cooling by natural convection is not an effective means for removing heat from the battery system. It is found that forced convection cooling can mitigate temperature rise in the battery. Nevertheless, a non-uniform distribution of temperature on the surface of the battery is inevitable and this makes thermal management difficult. As a better means of suppressing increases in temperature, a heat pipe has been used to effect heat dissipation. The connection between the heat pipe and the battery wall pays an important role in heat dissipation. Inserting the heat pipe in to an aluminum fin appears to be suitable for reducing the rise in temperature and maintaining a uniform temperature distribution on the surface of the battery.