# A Review on the Thermal Hazards of the Lithium-Ion Battery and the Corresponding Countermeasures
## 5 Management and Countermeasures
### Battery Management System
Commonly, it consists of three categories: the organic, the inorganic and the eutectic. The organic PCM contains carbon element, in which paraffin is the most common compound. For organic PCM, it possesses the advantage of no needing a container as their volume variation is relatively low, besides the chemical stability and non-corrosiveness [250]. The inorganic PCMs usually contain one or more metallic atoms. They have a good thermal conductivity and latent heat. Additionally, they are nonflammable and nontoxic. Nevertheless, some of them are corrosive and the reversibility of phase change is difficult to maintain in the long term. Moreover, the metals contained in inorganic PCM result in a high density which greatly limits its practical application. The eutectic PCM is a specific mixture of the previous PCMs, which permits the obtainment of a PCM with properties different to pure materials. For most PCMs, their latent heat is large, while their thermal conductivity is relatively poor. Hence, considerable studies have been carried out to enhance the thermal conductivity of existing PCMs as displayed in Table 3, and some other materials with high thermal conductivity such as expanded graphite (EG), foamed metal and nanomaterials are also introduced to synthesize composite phase change material (CPCM). [PERSON] et al. [251] developed an improved BMS based on the CPCM with aluminum boxes. Their results showed that the CPCM could significantly reduce the average temperature and improve temperature uniformity of a battery pack. [PERSON] et al. [252] investigated the cooling effectiveness of CPCM on the thermal response of a battery under overcharge condition and found that the battery cooled down remarkably as compared to the natural convection condition when CPCM was attached to the pouch battery. [PERSON] et al. [253] compared two CPCMs, a highly thermal conductive 60 wt.% RT44 HC/EG composite and a 60 wt.% RT44 HC/fumed silica composite with a lower thermal conductivity. Their results indicated that the low thermal conductivity of the CPCM would induce an even higher temperature difference over the battery pack in the absence of PCM. In summary, each type of BMS has its own merits and drawbacks, herein a comparison is conducted among these different types of BMS, shown in Table 4. Most scholars agree on the fact that air cooling is easy to operate but is not enough to cope with the temperature elevation of battery. Liquid cooling is performant but complex and presents the shortest lifespan. As for PCM, the leakage danger is a problem in application, thus a container is necessary. Nowadays, many researchers have focused on developing a combined battery management system (CBMS), in which more than one of the above thermal management methods are applied. In this way, different methods can complement mutual strengths and weaknesses to present excellent performance. [PERSON] et al. [263] developed a hybrid thermal management system for LIB-integrated PCM with forced-air cooling, as depicted in Figure 23. This CBMS successfully prevented heat accumulation and maintained the maximum temperature under 50 \({}^{\circ}\)C, in which the PCM dictated the maximum temperature rise and temperature uniformity within the battery pack while forced air convection