For both small-scale batteries and large-scale solar power plants heat transfer must be controlled. Heat transfer can be divided into the three modes: conduction, convection and radiation.
Heat conduction and heat convection are analogous to mass transfer by diffusion and convection and can be modelled in analogy with mass transfer. One difference between heat and mass transfer by convection is that heat itself can cause convection. This phenomenon called natural convection may be an important factor to consider.
Heat is also transferred between objects due to radiation. All surfaces irradiate electromagentic radiation (heat). The irradiation effect is proportional to the absolute temperature to the power of four. Thus, this mode of transfer is significant mostly for high temperatures.