Method and device for automatically equalizing voltages of power battery groups

Abstract

The invention discloses a method and device for automatically equalizing voltages of power battery groups. Each single battery of the serially connected power battery groups is connected with an electronic switch, the serially connected power battery groups are connected with a charge-discharge circuit through the electronic switches, and the voltages of the serially connected power battery groups are compared by detecting voltages at two ends of each single battery in real time; a first electronic switch connected with the first single battery is switched on when the voltage of the first single battery is larger than that of a second single battery, and the first electronic switch of the first single battery is switched off after the first single battery charges the charge-discharge circuit; and a second electronic switch connected with the second single battery is switched on, and the charge-discharge circuit charges the second single battery, thus the voltages of the first single battery and the second single battery are equalized, and all the processes are sequentially repeated till the voltages of all the single batteries of the serially connected power battery groups are equalized. According to the method and device for automatically equalizing the voltages of the power batter groups, disclosed by the invention, direct equalization between the high-voltage single batteries and the low-voltage single batteries is realized in the serially connected power battery groups in short time.

Description

technical field [0001] The invention belongs to battery pack management systems in various fields such as electric vehicles, in particular to an automatic equalization technology for series-connected battery packs. Background technique [0002] Today's batteries have been widely used in various fields, especially in today's rapid development of electric vehicles, power batteries have been regarded as one of the key technical components. A single battery has a fairly low voltage, typically in the range of 2.5-4.2V, but is not sufficient for applications with higher voltage and current requirements, and higher voltage requirements can be achieved by connecting battery cells in series. When charging battery packs working in series, how to ensure fast, efficient and automatic equalized charging of the battery packs during the charging process is a key technology to ensure the safety and reliability of single batteries and to fully exert their performance. [0003] The battery c...

AI Technical Summary

Problems solved by technology

[0006] At present, the first two technologies are widely used, but the problem is that the energy released by the battery cells through the shunting of the resistors will cause a large amount of heat generated by the resistors, and the balance current will be limited. It is only suitable for small capacity and a small number of cells connected in series. Battery

However, to transfer electric energy to low-capacity monomers through inductance, the idea is complicated, there are many components, and the control complexity is very high, and most of them are transmitted step by step through adjacent monomers, so multiple energy transfers will also lead to greater energy consumption. energy loss

[0007] Chinese patent application 201010244377 discloses a dynamic balanced charging and discharging method for power batteries. This method needs a balanced power supply when realizing the equalization of series-connected power batteries. The balanced power comes from the entire series-connected power batteries. At the same time, it can only , or discharge can achieve balance, so its scope of application is small; at the same time, the power supply of the balance power supply comes from the entire series-connected power battery pack. It is difficult to achieve complete balance of single cells, and in the process of equalization, it is also necessary to control the current of the balanced power supply. Therefore, this technology has defects such as complex control system and poor balance of single cells.

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