At present, the battery management system at home and abroad is more focused on the field of electric vehicles. The energy storage battery management system is a key part of the battery energy storage power station. The technology research and development of most battery companies in China is just beginning. A lithium-ion battery management system suitable for large-capacity energy storage technology is proposed in the literature. The system is analyzed from the perspective of structure, function and management of the hierarchical management system. Other major countries (such as the United States, Europe and other developed countries) have carried out research and development in the key technical areas of energy storage, and related technology research and development and demonstration activities have progressed rapidly.
In this work, from the perspective of environmental protection and economy, the energy storage battery selects part of the battery of the nickel-hydrogen power battery system of the electric bus after decommissioning, and designs the energy storage battery management system. The LTC6803 performs voltage and temperature information acquisition of the entire energy storage system and control of the battery pack equalization function.
1. Energy storage system architectureThe battery management side architecture of the energy storage system designed in this work is shown in Figure 1. It can be divided into three basic units: acquisition, control and processing and peripherals. The single-chip microcomputer system uses Freescale 16-bit MC9S12XEG128 as the microcontroller, the acquisition unit includes battery pack voltage sampling and temperature sampling; the current control unit includes battery pack equalization control and relay control; the processing and peripheral unit is mainly responsible for single-chip signal processing and communication peripherals. Control of other modules.
LTC6803 is widely used in electric vehicles and energy storage because of its high sampling accuracy and simple wiring. Therefore, LTC6803, a power management chip, is used as the battery front, H≤ and temperature sampling front end. It integrates 12 voltage sampling. And 2 channels of temperature sampling, with a controllable battery equalization switch, equalize the battery if necessary to maintain battery consistency.
2, power management chip LTC6803 hardware circuit design 2.1, LTC6803 basic schematic diagram and introductionIn this design, C0 in Figure 2 is connected to the negative terminal of the battery pack, C1 to C12 are voltage acquisition ports, and S1 to S12 are equalization switches; GPIO. And VTEMP. The pin is connected to the temperature acquisition module. It should be noted that the power supply of the LTC6803 is completely provided by the battery pack. The control board is not required to configure the power supply circuit. If connected to the isolated power supply, the LTC6803 can be turned off simply by disconnecting the pin V.
LTC6803 has an SPI bus compatible serial port, through which the MCU can exchange data, and the MCU can collect the voltage and temperature information of the battery pack and control the battery equalization circuit in real time by configuring the corresponding internal registers of the LTC6803. In Figure 1, the SPI signal isolation circuit uses an ADuM3150 isolation chip with four high-speed channels to ensure stable transmission of the SPI signal.
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