Abstract: To solve the heat dissipation problem of lithium-ion power battery (battery for short), a new honeycomb type liquid cooling module was developed for cylindrical battery. A three-dimensional thermal model was established based on the finite element commercial software ANSYS FLUENT. The heat dissipation effects of battery module were analyzed, and the model was validated by using a test platform by simulations. On the basis of this, an improved liquid cooling structure by adding the deflector was proposed and the three-dimensional temperature distribution of the battery module under different coolant temperatures and flow rates was quantitatively analyzed. The results of the simulations and tests illustrate the correctness of the three-dimensional model of the battery module and the rationality of the heat dispersion structure. The temperature and velocity of the coolant has good cooling effects on the temperature and distribution of the battery module, and should be controlled reasonably.