## 1 Introduction
However, an increased rate of charging/discharging results in a sudden rise in temperature which requires a considerable amount of air to be directed towards the battery module to abate the raised temperature [21; 22]. [PERSON] et al. [23] investigated the cooling effect on a cylindrical battery pack with different arrangement structures and forced air cooling strategies through a numeric simulation method, to determine the optimal design of a battery pack. [PERSON] and [PERSON] [24] put forward a novel reciprocating air cooling style which can improve the temperature uniformity, and proposed a lumped-capacitance thermal model and flow network model. Further, [PERSON] et al. [25] also proposed an effective method of reciprocating air flow cooling, which could control the battery temperature well. [PERSON] et al. [26] proposed a flow resistance network model to calculate the velocities in parallel channels in an air-cooled BTMS with Z-type flow and, furthermore, a transient heat transfer model was incorporated with this model to calculate the battery cell temperature. [PERSON] et al. [27] combined the flow resistance network model with the Newton method to optimize the angles of the divergence and convergence ducts in BTMS with Z-type flow. Subsequently, the same research group developed a steady heat transfer model to calculate the battery cell temperature [28]. Studies have proven that electrochemical models coupled with thermal models offer good performance in investigating the electrochemical and thermal behavior of battery cells [29]. To achieve better cooling performance, several researchers have combined different cooling methods to the electrochemical-thermal model [30; 31]. Numerous studies have implemented and validated thermal mathematical models that analyze convective heat transfer from the surface of battery cells [24; 32; 33; 34; 35; 36; 37]. However, these models approach the heat transfer of a cell as a single parameter, which reflects the overall performance of an accumulator. This method can be a good approximation when the cells are positioned in a free air stream and the distribution of air is uniform throughout the battery pack. However, EV battery packs need to be compact and tightly packaged for a good space efficiency. Therefore, for a more realistic approach, one should consider the local heat transfer coefficients of a battery and how they affect the temperature gradients inside the cells. In this paper, a segmented thermal resistance model for cylindrical batteries in a horizontal position configuration is proposed. The local convective heat transfer coefficients are determined using computational fluid dynamics (CFD) simulations and then introduced into a transient 1D mathematical model to predict temperature variations inside the battery's cells. The transient model represents a dynamic behavior of the electric power-train, characteristic for driving on a racetrack. The numerical model allows the evaluation of a battery pack casing's influence on the local temperatures of a large-scale pack and the calculation of necessary air flow to maintain local maximum temperatures under the desired limit. The main contribution of this study is the development of such a numerical model and its application to thermal management of a Formula Student electric vehicle battery pack with forced air cooling.