Large-scale And Flexible Control Technology Research For Battery Formation Process Equipment

With the new growing market and the development of electric vehicles, the demand for all kind of batteries has grown. So, the existing stand-alone battery formation process and equipment can not meet market demand. Battery formation equipment control accuracy and formation strategy affect the battery capacity and service life. Inaddition, the scale of battery formation equipment directly impacts battery production efficiency and cost. Based on the traditional stand-alone formation equipment, this paper proposed a large-scale and flexible control strategy for the battery formation process equipment, and the key technologies of equipment development process have been studied. The study includes: energy efficiency and accuracy of the battery formation process control strategy, large-scale formation control node synchronization methods and flexible design method based on the battery formation equipment faults and so on.The energy flow topology, information flow topology and software platform are the basis of the battery formation process equipment research. This paper firstly studies the battery formation model, and chooses DC bus structure as the energy flow topology. The DC bus energy flow topology is not only energy conservation, but also pollution-free for the higher lever electricity grid speciality. Secondly, a cheap and facility network, which exactly coincides with the control system development trend, has worked as the bus structure for large-scale formation equipment. In addition, an information flow topology is adopted to the large-scale process terminal node access. Finally, in order to make the equipment flexible, real-time operation system is used to realize the battery formation process control on the embedded platform.Based on the analysis of the DC bus energy flow topology, this paper built the formation process control model which consist of the current loop control and voltage loop control, solved the high-precision injection energy issues during the battery formation process. According to the experimental data, the voltage and current transfer function are derived by the battery model. Through the transfer function, this paper designes the formation control strategy and decision-making control strategy to ensure the high-accuracy steady states response and smooth switching of voltage and current. At the same time, in the design of large-scale formation process equipment, single formation and continuous formation step control strategy based on batteries output is analyzed, a step continuous formation strategy based on worker’s labor strength is put forward. The strategy assures the grid energy consumption on one hand, and achieves electric energy feedback during battery discharge process to avoid electric energy waste in battery formation process on the other hand.There are hundreds of intelligent terminal formation nodes in the large-scale battery formation process equipment, the data transmission for terminal formation nodes control strategy becomes a key problem to be solved. This paper analyzes the relationship between the number of battery formation process terminal nodes and sample time according to switched industrial Ethernet delay. A predictive compensation clock synchronization algorithm with high-precision is proposed based on shifting time windows. And an experiment further demonstrates the predictive compensation algorithm which has better precision than traditional clock synchronization algorithm. This research provides theoretical basis for large-scale node arrangement based on Ethernet.In order to make the battery formation process equipment intelligent, flexible and automatic, this paper supplies a battery formation process equipment flexible design including terminal nodes fault detect, large-scale terminal nodes topology reconstruction, the process equipment ability to extension, and fully automatic control performance. A variable period heartbeat frame method is mentioned based on terminal nodes fault detection, and the performance on large-scale network is verified by performance parameters. For large-scale terminal node equipment faults and repairing topology structure reconstruction, this paper presents an object function optimization method to assure the optimal grid consumption features under the condition of single and continuous step control battery formation strategy. Protocol convert method is proposed in heterogeneous equipment access methods, which implements compatibility and coexistence of new battery formation process equipment of industrial Ethernet and old non-Ethernet devices, avoids wasting the repetitive investment and resource. In the meantime, to satisfy the battery formation process equipment future trend, a direct digital synthesizer multi-motor synchronous algorithm is developed for the automatic control. By solving the control technical problems mentioned above, this paper develops a large-scale and flexible distributed lead-acid battery formation process equipment, which have been used in Camel Group Co., Ltd. During the enterprise applications, the network control and management of lead-acid battery formation process is well done. This large-scale battery process equipment can also be used in the manufacturing process of Li-Ion battery, Ni-MH battery and other types of battery production process by adjusting the parameters and amending process description file. The successful application of the device has important significance to generalize the network battery formation process equipment in our country.