Installing lithium-ion batteries on new or refitted diesel-electric submarines has become increasingly interesting
based on their relatively high energy density and specific energy compared to alternative chemistries such as
lead-acid batteries. However, lithium-ion batteries can develop a thermal runaway. A thermal runaway can typically
be initiated once critical temperature limits are exceeded. The main objective of this research is therefore to
investigate the implications on preliminary submarine system design based on the thermal behaviour of lithiumion
batteries and to quantify the thermal behaviour and design implications. A thermal model of a lithium-ion
battery module has been formulated. Electrical behaviour and heat generation is modelled on a cell level. At
module level, heat transfer has been modelled according to a lumped thermal capacity approach. Cooling is
modelled to provide insight into typical cooling rates regarding thermal management. Conclusions have been
drawn regarding the cell temperatures in the module based on three operational profiles. A submerged sprint can
be sustained up to 1.0C without cooling, whereas for a covert transit or covert surveillance cooling is typically
necessary. Typical cooling rates vary between 60 W and 185 W, where the effects of cooling are most significant
for covert transit and covert surveillance. Module optimisation provides increased cooling rates while increasing
the energy density and specific energy. Cell temperatures remain relatively constant after the fourth cell in a row,
meaning that module design is typically not limited by the number of cells.
