## 1 Introduction  
Traditional fuel vehicles consume a lot of oil resources, and the exhaust gas emitted by the vehicles will deteriorate air quality, be detrimental to human health, and lead to the greenhouse effect. Currently, the energy policy and development models have changed, and many countries are vigorously developing electric vehicles to curb global warming and reduce greenhouse gas emissions. Among the many kinds of electric vehicle (EV) energy storage technologies, the lithium-ion battery (LIB) stands out because of its high output power, long service life, and high output voltage [1; 2; 3]. Although LIB has many advantages, it is very sensitive to temperature, the performance of LIB will decline when the temperature is below 0 \({}^{\circ}\)C or above 45 \({}^{\circ}\)C. If the heat generated by LIB accumulates in the battery pack and cannot be eliminated in time, it will cause rising temperatures, resulting in problems such as a fast-aging speed, few cycles, and short service life of the LIB [4; 5; 6]. In serious cases, it is prone to local overheating, liquid leakage, and even thermal runaway [7; 8; 9]. Therefore, BTMS must be used for temperature control [10; 11]. The acceptable operating temperature range of LIB is \(-20\)\({}^{\circ}\)C to 60 \({}^{\circ}\)C, while the most suitable operating temperature range is 20 \({}^{\circ}\)C to 40 \({}^{\circ}\)C, and the battery temperature difference is kept below 5 \({}^{\circ}\)C [12]. The common cooling methods of BTMS include air-cooling, liquid-cooling, phase change material (PCM) cooling, heat pipe cooling, and the combination of the above systems. Liquid-cooling has high cooling efficiency, but its structure is complex and heavy, and coolant leakage may cause serious consequences [13; 14; 15; 16]. PCM cooling has a large heat capacity and does not consume electricity, but is unsuitable for use in BTMS because of the low thermal conductivity of PCM and volume expansion during phase transformation [17; 18; 19]. Due to the high thermal conductivity, the cooling effect of heat pipe cooling is good, but it has a high cost and process requirements [20; 21; 22; 23; 24]. Air-cooling has the advantages of light weight, low cost, and convenient maintenance, but the low thermal conductivity of air leads to a poor cooling effect. Therefore, many works are trying to improve the thermal performance of air-cooling. [PERSON] et al. [25] tested the influence of the inlet and outlet position of air-cooling BTMS on cooling efficiency. They found that symmetrical BTMS has a higher cooling performance in the case of the inlet and outlet being located at the centre of the positive pressure air supply system. To improve the cooling efficiency, [PERSON] et al. [26] proposed a new type of forced air-cooling BTMS, which adopts a thermal silica cooling plate-aluminate thermal plate, the experimental results show that it can effectively improve the thermal performance. Open-cell metal foam is a new functional material with a large specific surface area, high thermal conductivity and remarkable thermal and mechanical properties. When the fluid flows through the cavity of the open foam metal, the complex three-dimensional network structure of the metal foam enhances the mixing capability for the fluid and enhances the convective heat transfer. At the same time, the mechanical and lightweight properties of foam metal can be used as energy-absorbing materials for spacecraft landing and vehicle collision. At present, it is widely used in the electronics, aerospace, and automotive industries [27; 28; 29]. Due to the excellent heat and mass transfer characteristics of open-cell foam metal, some researchers focus on metal foam-PCM composite materials for application in the BTMS [30; 31; 32]. The results of the study show that the effective thermal conductivity of PCM can be greatly improved by adding foam metal, which can further reduce the surface temperature of the battery. However, this method also has obvious shortcomings.