Coding and transmission methods of voltages of cells and device

Abstract

The embodiment of the invention provides a coding method for voltages of cells. The coding method comprises the steps that the average value of the voltages of the cells in a module is obtained; and according to a preset coding table, the difference values between the voltage values of all the cells in the module and the average value are coded to obtain a difference value coded value, wherein thepreset coding table is obtained by coding the voltage difference values in a preset range, the preset range is divided into a plurality of continuously-distributed sub-intervals, and the sub-intervalwith the minimum absolute value of the voltage difference values has the highest coding accuracy. According to the coding method, transmission accuracy is improved on the whole, and the communicationload rate is decreased.

Description

technical field [0001] The invention relates to the field of electric vehicles, in particular to a method and device for encoding and transmitting cell voltage. Background technique [0002] With the continuous reduction of traditional energy sources and the continuous improvement of environmental protection awareness, new energy vehicles have been greatly developed. New energy vehicles usually use batteries as the source of power. In order to ensure driving safety, the state of batteries needs to be monitored. [0003] The battery management system (BMS, Battery Management System) monitors the battery cell status of the battery pack, and uses the collected data of the battery to estimate parameters such as SOC. The cell voltage is one of the important monitoring data. Since the range of the cell voltage is very small, the sampling accuracy of the cell voltage has a great influence on the estimation of the BMS. [0004] At present, the distributed cell voltage collection me...

AI Technical Summary

Problems solved by technology

During the transmission of the cell voltage, the cell voltage is mainly encoded with a fixed-precision encoding method. When the accuracy is high, more bits are required to represent it. For example, when the accuracy of the cell voltage is 1mv, each single cell The cell voltage needs 12 bits of data to represent, and each CAN message can transmit 64 bits. In this way, each CAN message can only transmit the voltage of 5 single cells. As the vehicle’s energy demand for the battery pack increases, the battery pack The number of internal single cells continues to increase, and the high-precision transmission method will cause an increase in the CAN communication load rate

When the accuracy is reduced, fewer bits of data can be used to represent the cell voltage, but it will also reduce the accuracy of the sampling data and affect the overall performance of the BMS

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