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This paper presents an improved scheme for the state-of-health (SOH) estimation, applicable to battery management system (BMS) of electric vehicles. The original scheme requires the prior information for the estimation, which is the prior SOH identified from the last charging. This limit implies that if a battery or its BMS is replaced, the prior SOH stored within the BMS no longer matches with the actual SOH, resulting in a critical error. To avoid this potential but critical pitfall, we newly devise an improved SOH estimation scheme. The original scheme is revised by adopting the fixed-point iteration method into its parameter estimation. By removing dependencies on the prior information, the revised scheme can function regardless of such replacements. The revised scheme is experimentally validated and demonstrated that even without the prior information, it can satisfy the requirement of the SOH estimation (within 3%) thanks to its improved design. [ABSTRACT FROM AUTHOR]

• A battery model considering the current density distribution is employed. • Direct cooling can significantly reduce the MAT on the cell. • Increasing flow velocity, thermal conductivity and latent heat can reduce the MAT. • Decreasing initial temperature and saturation temperature can reduce the MAT. Lithium-ion batteries will produce a lot of heat during charging and discharging. If the heat cannot be exported in time, it will significantly increase the temperature and temperature difference in the battery system, which can seriously affect the capacities, lives and safety of the batteries. Direct evaporation cooling is a new and efficient battery thermal management method. It is necessary to comprehensively understand the effects of its design and operation parameters on the performance of the battery thermal management system. In this paper, a direct evaporation cooling battery thermal management system was designed with the refrigerant of R134a. The electric-thermal coupled model of the lithium-ion battery was used, which considered the current density distribution in the battery. The performance of the battery thermal management system was obtained by numerical simulation based on the transient VOF method. It was found that compared to air natural convection cooling and liquid cooling, direct evaporation cooling could significantly reduce the maximum temperature on the cell under the 3 C discharging condition. The effects of the initial temperature, flow velocity, saturation temperature, thermal conductivity, and latent heat of the refrigerant on the performance of the battery thermal management system were further investigated. It could provide theoretical references and technical means for the design and analysis of the direct evaporation cooling battery thermal management system in the future. [ABSTRACT FROM AUTHOR]

• Optimisation of PCM based cooling coupled with liquid cooling system. • System weight and consumption of different configurations is evaluated. • Suggesting a 2-sided cold plates hybrid system for BTMS of pouch cells. • Suggested hybrid BTMS can withstand cell-to-cell variation of battery cells. In this paper, a novel design for hybrid battery thermal management systems (BTMS) is proposed and evaluated from the economic and engineering perspectives. Numerical models are compared with phase change materials (PCM) BTMS. Further, the suggested hybrid cooling system's thermal performance at the pack level is investigated considering cell-to-cell variation. A three-dimensional thermal model is used for the numerical simulation of the battery cooling system. The probability distributions is utilised for the cell-to-cell variations of a 168-cell battery pack. Results shows that for a 53 Ah lithium-ion battery (LIB) under a 5 C discharge rate, a hybrid cooling system with two-sided cold plates can reduce the maximum temperature from ∼ 64 ∘ C to 46.3 ∘ C with acceptable system weight and power consumption, which is used for further pack level simulation. It is concluded that the two-sided cold plate hybrid design system can manage the maximum average temperature as well as temperature difference of cells in the desirable range at extreme cases. [ABSTRACT FROM AUTHOR]