Lithium batteries must be connected in series to achieve large capacity and high‐power output. Battery management system (BMS), which is designed to protect battery pack from damage and increase battery life, is important in electrical power system. The present equalisation techniques have many disadvantages: The passive balancing wastes energy and generates heat, while active balancing is complex. This study proposes an intelligent BMS with dynamic equalisation (DBMS) which contains active and passive balancing circuit independently per cell. Experimental results indicate that DBMS can reduce the inconsistency among cells. Moreover, the DBMS can assist battery stack to store and release more energy. Besides, the battery stack with DBMS gives an energy efficiency of 96.5% which is 7.7% higher than that without balancing. In addition, the battery stack with DBMS can reduce the maximum state of charge difference of cells from 10.415% to 4.51% after three charge–discharge cycles. What is more, the DBMS is simple and can decrease the auxiliary power level and the system heat. Such a DBMS will help us to provide a high‐performance battery pack.
17 July 2017 in International Journal of Energy Research
Ice slurry is widely used in the field of ice storage air conditioning, district cooling, seafood preservation, and milk processing. Ice generation using supercooled water is efficient, and the system structure is compact. However, a secondary refrigerant cycle is usually used in order to control the wall temperature and to prevent the “ice blocking” problem. Therefore, an ice generation system using supercooled water with a directed evaporating method is proposed and fabricated in order to improve the system performance, which is tested in the experiment. Then, two calculation methods are used to study the performance of entire ice generation system. We concluded that: (1) The system could run steady without “ice blocking” in the condition where the supercooled water temperature was higher than 271.7 K and the velocity was more than 2.1 m/s. The entire system COP could reach 1.6 when the condenser temperature was about 319 K. (2) The system COP could be improved by about 20% if the compressor output power was based on the theoretical refrigerant cycle. The system COP could reach about 2.5 if the proportion of extra power was 3% and the condenser temperature was 308 K. (3) The system COP with a directed evaporating method was about 14% higher than that with an indirected evaporating method. (4) An orthogonal test was built to quantify the influence of different critical parameters. The influence of factors on the system COP were as follows: condenser temperature > water flow > adiabatic compressibility > refrigerant. This work provided a good look at the performance of an ice generation system using supercooled water with a directed evaporating method. It can play an important role in guiding the design of a system of ice generation using supercooled water.