CN105150874B - Power battery management system and power supply control method thereof - Google Patents

Abstract

The invention provides a power battery management system and a power supply control method thereof. The power battery management system comprises a BMU, a plurality of power battery modules and CSCs (computer controlled systems) corresponding to the power battery modules; the CSC comprises a first DC/DC and a second DC/DC; the input ends of the first DC/DC and the second DC/DC are connected with the anode and the cathode of the corresponding power battery module, and power is taken from the power battery module; the output end of the first DC/DC is connected with the input end of the corresponding CSC and used for supplying power to the CSC; the output of the second DC/DC is connected to the input of the BMU for powering the BMU. By adopting the technical scheme of the invention, the power battery module can be used as the only power supply of each power battery system, the volume and the weight of the electric automobile are reduced, and the cost of the electric automobile is reduced.

Description

Power battery management system and power supply control method thereof

technical field

The invention relates to the technical field of power batteries, in particular to a power battery management system and a power supply control method thereof.

Background technique

With the attention and investment of governments and car companies in electric vehicle projects, some large car manufacturers and battery suppliers have done a lot of research and experiments on various power batteries, and successfully developed related battery management systems (Battery Management System; BMS).

BMS has a great impact on the safe operation of electric vehicles (Electric Vehicle; EV), the selection of vehicle control strategies, the selection of charging modes, and operating costs. Regardless of whether the vehicle is running or charging, the BMS must complete the real-time monitoring and fault diagnosis of the battery status, and inform the vehicle controller or charger through the bus, so as to adopt a reasonable control strategy to achieve effective and efficient The purpose of using the power battery.

However, the power battery in the existing BMS is only used as a power source to provide power to the EV, while other units in the battery management system, such as the power battery monitoring unit (Cell Supervision Circuit; CSC), battery management system unit (Battery Management Unit; BMU), The current data acquisition unit (Current Supervision Unit; CSU) and the insulation detection module (Isolation Monitor Module; IMM) and the like all need external power supply. However, there are generally multiple CSCs and BMUs in a BMS, which leads to too many external power supplies in the entire EV system, increasing the volume, weight and cost of the EV.

Contents of the invention

The invention provides a power battery management system and a power supply control method thereof to solve the problem of too many external power sources in the entire EV system, which increases the volume, weight and cost of the EV.

The present invention provides a power battery management system. The system includes a power battery management unit, a plurality of power battery modules, and a power battery monitoring unit corresponding to each of the power battery modules;

The power battery monitoring unit includes a first DC step-down power supply module and a second DC step-down power supply module; the input terminals of the first DC step-down power supply module and the second DC step-down power supply module are all connected to the corresponding The positive and negative poles of the power battery module are connected to get electricity from the power battery module;

The output terminal of the first DC step-down power supply module is connected to the corresponding input terminal of the power battery monitoring unit for supplying power to the power battery monitoring unit; the output terminal of the second DC step-down power supply module It is connected with the input end of the power battery management unit, and is used for supplying power to the power battery management unit.

The present invention also provides a power supply control method for a power battery management system, the method comprising:

According to the corresponding relationship table between the open circuit voltage and the remaining power of each power battery module, the size of the remaining power of each power battery module is obtained;

Comparing the size of the remaining power of each of the power battery modules to obtain the smallest remaining power;

According to the minimum remaining power, calculate the difference between the remaining power of each of the other power battery modules and the minimum remaining power;

calculating the generating capacity of each of the power battery modules according to the difference;

According to the power generation capacity of each of the power battery modules, sort each of the power battery modules according to the power generation capacity from large to small;

Collect the magnitude of the input current of each power battery management unit;

Obtain the magnitude of the input current of each of the power battery management units, and calculate the number M of the power battery modules that need to generate electricity;

According to the calculated M power battery modules, M+1 power battery modules are sequentially selected from among the power battery modules sorted from large to small in power generation capacity to supply power. ;

Control the M+1 power battery modules to supply power.

Further, in the above-mentioned power supply control method of the power battery management system, the power supply control method adopted in each power battery module includes:

Collect the power of each cell in each of the power battery modules;

judging whether the power of each battery cell is greater than the preset battery power value;

When the electric quantity of the battery cell is greater than the preset electric quantity value of the battery cell, the electric quantity of the corresponding electric cell is controlled to be transferred to the corresponding power battery module.

When the electric quantity of the battery cell is less than the preset battery electric quantity value, the electric quantity of the corresponding power battery module is controlled to be transferred to the corresponding electric cell.

In the power battery management system of the present invention, the first DC/DC in each CSC takes power from the power battery module to supply power to the corresponding CSC, and controls the second DC/DC in each CSC to supply power to BMU1, so that the BMS Each power battery module can be used as a power source to provide power to the EV, and can also be used as a control power source to provide power to the BMU1 or the corresponding CSC, so that the BMU1 or the corresponding CSC does not need an external power supply and realizes self-power supply. By adopting the technical scheme of the invention, each power battery module can be used as the sole power source of the BMS system, which reduces the volume and weight of the EV, and reduces the cost of the EV.

The power supply control method of the power battery management system of the present invention collects the OCV of each power battery module and sends it to the BMU, and the BMU calculates the number M of the power battery modules that need to generate electricity, and follows the order from large to small Control M+1 power battery modules to supply power to components other than CSC, realize the priority discharge of power battery modules with higher power generation capacity, and balance the power generation capacity among power battery modules. The performance of the power battery module and the service life of the power battery module can be improved by adopting the technical scheme of the invention.

The power supply control method of the power battery management system of the present invention also collects the power of each battery cell in each power battery module, and when the battery voltage in each power battery module is greater than or lower than the preset battery power value, it can realize It ensures the power transfer between the battery cell and the power battery module, balances the power of each battery cell in the power battery module, and improves the performance of the power battery module. Adopting the technical solution of this embodiment can improve the performance of the power battery module and the service life of the power battery module.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of an embodiment of the power battery management system of the present invention;

Fig. 2 is a schematic structural diagram of another embodiment of the power battery management system of the present invention;

FIG. 3 is a schematic circuit diagram of a power battery management system corresponding to the first power battery module 21 in FIG. 2;

4 is a schematic structural view of an embodiment of a power battery pack of the power battery management system of the present invention;

Fig. 5 is a schematic structural diagram of another embodiment of the power battery management system of the present invention;

Fig. 6 is a flow chart of an embodiment of the power supply control method of the power battery management system of the present invention;

Fig. 7 is a flow chart of another embodiment of the power supply control method of the power battery management system of the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of an embodiment of the power battery management system of the present invention. As shown in Fig. 1, the power battery management system of this embodiment includes a BMU1, a plurality of power battery modules, and corresponding CSC. As shown in Figure 1, the power battery management system of this embodiment is taken as an example including n power battery modules, as shown in Figure 1, the power battery management system of this embodiment may specifically include a first power battery module 21. The second power battery module 22, ..., the nth power battery module 2n, and the first CSC31, the second CSC32, ..., the nth CSC3n corresponding to each power battery module.

The first CSC31 is fixed on the corresponding first power battery module 21 through the shell, and the positive and negative poles of each cell in the power battery module 21 and the first power battery module are connected through the connector interface and wiring harness. The positive and negative poles of group 21 are connected.

The first CSC31 includes a first DC step-down power supply module (Direct-current/Direct-currentModule; hereinafter referred to as DC/DC) 311 and a second DC/DC312; the input terminals of the first DC/DC311 and the second DC/DC312 Both are connected to the positive and negative poles of the corresponding first power battery module 21 for taking electricity from the corresponding first power battery module 21 . The output end of the first DC/DC311 is connected to the input end of the corresponding CSC31, and the first DC/DC311 is used to supply power to the CSC31; the output end of the second DC/DC312 is connected to the input end of the BMU1, and the second DC/DC312 is used for Provide power to BMU1. For example, the first DC/DC311 takes power from the corresponding first power battery module 21, converts the voltage into a voltage that drives the first CSC31 to work normally, and supplies power to the first CSC31. In practical applications, the first DC /DC311 supplies power to the micro control unit (Micro Control Unit; MCU) in the first CSC31, so as to be able to control the normal operation of the first CSC31. The second DC/DC 312 takes power from the first power battery module 21, converts the voltage into a voltage for driving the BMU1 to work normally, and controls the BMU1 to work normally. Moreover, a first switch may also be set in the first CSC31, for example, specifically, the first switch is set between the second DC/DC312 and the line of the BMU1 to control the second DC/DC312 to supply power to the BMU1.

Specifically, after the first CSC31 works normally, the MCU in the first CSC31 can control the first switch to be turned on or off, and when the first CSC31 detects that it needs to supply power to the BMU1, the MCU controls the first switch If it is turned on, the second DC/DC312 supplies power to the BMU1; otherwise, the MCU controls the first switch to turn off, so that the second DC/DC312 does not supply power to the BMU1. When BMU1 is powered on, because BMU1 is connected to the load (Load) in the EV, such as electronic components such as relays, CSU (Current Supervision unit), IMM (Isolation Monitor Module), etc., the load or CSU is driven normally. Work, so as to realize the self-power supply of the whole BMS system.

It should be noted that, in this embodiment, the second power battery module 22, ..., the nth power battery module 2n is the same as the first power battery module 21, and the second CSC32, ..., the nth power battery module CSC3n is the same as the first CSC31. For the connection relationship and working principle between each power battery module and the corresponding CSC, please refer to the previous description, and no more examples will be given here.

In the power battery management system of this embodiment, the first DC/DC in each CSC takes power from the power battery module to supply power to the corresponding CSC, and controls the second DC/DC in each CSC to supply power to BMU1, so that the BMS Each power battery module in the battery can be used as a power source to provide power to the EV, and can also be used as a control power source to provide power to the BMU1 or the corresponding CSC, so that the BMU1 or the corresponding CSC does not need an external power supply and realizes self-power supply. By adopting the technical solution of this embodiment, each power battery module can be used as the sole power source of the BMS system, which reduces the volume and weight of the EV, and reduces the cost of the EV.

In the power battery management system of the above-mentioned embodiment, each power battery module is composed of a plurality of battery cells connected in series, and the power of each battery cell is different. If it is not controlled, the power battery module will be low when discharging Over-discharging of low-power cells will lead to over-charging of low-power cells in the power battery module during charging, which will end the charging process early, affect the performance of the power battery module, and shorten the service life of the power battery module. In order to solve the above problems, the present invention also provides the following power battery management system.

Fig. 2 is a schematic structural diagram of another embodiment of the power battery management system of the present invention. As shown in Fig. 2, the power battery management system of this embodiment is based on the embodiment shown in Fig. 1, and the first CSC31 further A third DC/DC313 is included. One end of the third DC/DC313 is connected to the positive and negative poles of each battery cell in the first group of cells 211 in the corresponding first power battery module 21, and the other end of the third DC/DC313 is connected to the first power cell The positive and negative poles of the battery module 21 are connected; when the power value of the battery cell in the first power battery module 21 is greater than the preset battery power value, the third DC/DC313 takes power from the corresponding battery cell, and The power is transferred to the corresponding first power battery module 21; when the power value of the battery cell in the first power battery module 21 is less than the preset battery power value, the third DC/DC313 will transfer from the corresponding first Take power from the power battery module 21 and transfer the power to the corresponding battery cells, so that the third DC/DC313 cooperates with the first CSC31 to realize the active equalization function of the first power battery module 21. Specifically, it can be The second switch corresponding to each battery cell is set in the first CSC31, and the second switch is set on the line between the third DC/DC313 and the corresponding battery cell, and the corresponding first power battery is controlled by the second switch The module 21 performs energy interaction with the cells in the first power battery module 21 .

It should be noted that, in this embodiment, the second power battery module 22, ..., the nth power battery module 2n is the same as the first power battery module 21, and the second CSC32, ..., the nth power battery module CSC3n is the same as the first CSC31. For the connection relationship and working principle between each power battery module and the corresponding CSC, please refer to the previous description, and no more examples will be given here.

Fig. 3 is a schematic circuit diagram of the power battery management system corresponding to the first power battery module 21 in Fig. 2, as shown in Fig. The output terminal is connected to the MUC314 in the first CSC31, and the first DC/DC311 takes power from the first power battery module 21 and supplies power to the first CSC31. The input end of the second DC/DC312 is also connected to the positive and negative poles of the first power battery module 21, the output end is connected to the BMU1 through the first switch Kp, and the second DC/DC312 is connected to the first power battery module 21. and supply power to BMU1, and the output terminals of BMU1 are respectively connected to CSU4, IMM5 and Load6 to make CSU4, IMM5 and Load6 work normally, so the power supply of CSU4, IMM5 and Load6 also comes from the first power battery module twenty one. One end of the third DC/DC 313 is connected to the positive and negative poles of each cell Cell I7 in the first power battery module 21 through the second switch Kb corresponding to each cell Cell I7, and the other end is connected to the first power battery module Group 21 is connected, so as to discharge the battery cell Cell I7 greater than the preset battery power value, and transfer the power to the first power battery module 21. The specific discharge process is indicated by the solid arrow in Figure 3 Or the third DC/DC313 takes power from the first power battery module 21, charges the battery cell Cell I7 less than the preset battery power value, and transfers the power of the first power battery module 21 to The specific charging process of the battery cell Cell I7 which is less than the preset battery power value is shown in the direction indicated by the dotted arrow in Figure 3 .

It should be noted that the first switch Kp and the second switch Kb are controlled by the MCU 316 in the first CSC 31 to control whether the second DC/DC 312 and the third DC/DC 313 work or not.

Specifically, BMU1 can be set with a preset battery power value. After the first CSC31 works normally, BMU1 controls the first CSC31 to collect the power of each battery cell Cell 17 in the first power battery module 21, and Report to BMU1; then BMU1 judges the relationship between the power of each battery Cell I7 and the preset battery power value. When the power of the existing battery Cell I7 is greater than the preset battery power value, BMU1 sends a control command to the first CSC31, and the first CSC31 receives the command and is controlled by the MCU314 in the first CSC31 to close the corresponding second switch Kb, the power of the battery cell CellI7 that is greater than the preset battery power value is transferred to the first power battery module 21 via the third DC/DC313, when the power of the existing battery Cell I7 is less than the preset battery power value, then The power of the first power battery module 21 is transferred to the battery cell Cell 17 which is less than the preset battery power value via the third DC/DC 313 .

It should be noted that the circuit diagram of the power battery management system corresponding to the second power battery module 22, ..., the circuit diagram of the power battery management system corresponding to the nth power battery module 2n is the same as that of the first power battery module The schematic circuit diagram of the power battery management system corresponding to 21 is the same. Please refer to the previous description for the connection relationship and working principle, and no examples will be given here.

In the power battery management system of this embodiment, by setting the first DC/DC, the second DC/DC and the third DC/DC in each CSC, each power battery module can be used as the only power source of the BMS system. At the same time, when When the battery voltage of each power battery module is greater than or lower than the preset battery power value, the power transfer between the battery cell and the corresponding power battery module is realized, and the power of each battery cell in the power battery module is balanced. , improving the performance of the power battery module. Adopting the technical solution of this embodiment reduces the volume and weight of the EV, reduces the cost of the EV, and improves the service life of the power battery module at the same time.

Fig. 4 is a schematic structural diagram of an embodiment of the power battery pack of the power battery management system of the present invention. As shown in Fig. 4, Pack x represents any power battery pack, and Pack x can use the power battery of the embodiment shown in Fig. 2 management system. As shown in Figure 4, the power battery pack Pack x BMU1 of this embodiment, the first power battery module 21, the second power battery module 22, ..., the nth power battery module 2n, and each power battery The module corresponds to the first CSC31, the second CSC32, ..., the nth CSC3n, CSU4, IMM5, Load6 and so on. For the detailed working process, please refer to the related records of the embodiment shown in FIG. 2 , which will not be repeated here.

In the power battery management system of the above embodiment, only how to supply power to the battery cells in the power battery module is described, but in the BMS system, a Pack is composed of multiple power battery modules connected in series, and each power battery module The capacity of the pack is also different. If it is not controlled, the power battery module with a lower capacity will also be over-discharged during discharge, and the power battery module with a lower capacity in the Pack will be overcharged during charging, and the charging process will end prematurely. Affect the performance of the power battery module and shorten the service life of the power battery module. In order to solve the above problems, the present invention also provides the following power battery management system.

Fig. 5 is a schematic structural diagram of another embodiment of the power battery management system of the present invention. As shown in Fig. 5, the power battery management system of this embodiment is further described in more detail on the basis of the embodiment shown in Fig. 2 In the power battery management system implemented, the first CSC31 also includes a first acquisition module 315 and a first communication module 316, and the BMU1 includes a second communication module 11; the first communication module 316 is connected to the second communication module 11, and the second A communication module 316 is also connected to the first collection module 315 . The first collection module 315 is used to collect parameter information of the corresponding first power battery module 21 , the information includes the open circuit voltage (Open Circuit Voltage; OCV) of the first power battery module 21 and the electric quantity of each battery cell. Since the first CSC31 is respectively connected to the positive and negative poles of each cell in the first power battery module 21 and the positive and negative poles of the first power battery module 21, the first collection module 315 can collect the first The parameter information of each power battery module 21, such as OCV, the power of each battery cell, temperature and power consumption current, etc.

After the first collection module 315 collects the parameter information of the first power battery module 21, the first communication module 316 is used to obtain the parameter information from the first collection module 315, and send the parameter information to the second communication module 11; The communication module 11 is used to receive the parameter information, realize BMU1 to monitor the use status of the first power battery module 21, balance the power of each battery cell in the first power battery module 21, and prevent improper use of the first power battery module 21. Power battery module 21. The first communication module 316 and the second communication module 11 can use any communication method, and the most commonly used communication method is Controller Area Network (CAN) communication.

It should be noted that, in this embodiment, the second power battery module 22, ..., the nth power battery module 2n is the same as the first power battery module 21, and the second CSC32, ..., the nth power battery module CSC3n is the same as the first CSC31. For the connection relationship and working principle between each power battery module and the corresponding CSC, as well as the connection relationship and working principle between each CSC and BMU1, please refer to the previous description, and will not describe them one by one here. example.

The dynamic BMU1 in the power battery management system of this embodiment also includes a storage module 12, an acquisition module 13, a comparison module 14, a calculation module 15, a second acquisition module 16 and a control module 17;

The storage module 12 is used to store the correspondence table between the OCV of each power battery module and the remaining power (State of Charge; SoC); the acquisition module 13 is connected with the storage module 12 and the second communication module 11 respectively, and the acquisition module 13 is used for The correspondence table stored by the storage module 12 and the OCV in the parameter information received by the second communication module 11 obtain the size of the SoC of each power battery module; 13 The size of the SoC of each power battery module obtained, compare the size of the SoC of each power battery module, and obtain the smallest SoC; the calculation module 15 is connected with the comparison module 14, and the calculation module 15 is used to obtain the minimum value according to the comparison module 14. Calculate the difference between the SoC of other power battery modules and the smallest SoC; and calculate the power generation capacity of each power battery module according to the differences.

The comparison module 14 is also used to sort the power battery modules according to the power generation capacity from large to small; the second collection module 16 is used to collect the size of the input current of each BMU1; the calculation module 15 is also connected to the second collection module 16 , the computing module 15 is also used to obtain the magnitude of the input current of the BMU1, and calculates the number M of power battery modules that need to generate electricity; the obtaining module 13 is also connected to the computing module 15, and the obtaining module 13 is also used to calculate the The M power battery modules 2 and the comparison module 14 sort each power battery module according to the sorting results of the power generation capacity from large to small, and from the power battery modules sorted from large to small in power generation capacity in descending order Select M+1 power battery modules for power supply; the control module 17 is respectively connected with the second communication module 11 and the acquisition module 13, and is used to select the M+1 power battery modules according to the acquisition module 13, through the second communication Module 11 sends instructions to control M+1 power battery modules to supply power.

For each power battery module, its OCV corresponds to SoC one by one, and the corresponding relationship table can be stored in BMU1 in advance. When the CSC collects the OCV of the corresponding power battery module and sends it to BMU1, BMU1 can look up the table to obtain the size of the SoC of each power battery module, which is recorded as SoC(x); compare the obtained SoC(x) to get The smallest SoC(x) is recorded as SoC(x)min; the difference between SoC(x) and SoC(x)min of other power battery modules is obtained by mathematical formula, which is recorded as ΔSoC(x); ΔSoC( x) is multiplied by the nominal capacity of each power battery module to obtain the power generation capacity of each power battery module, which is recorded as Cap(x); sort the obtained Cap(x) from large to small.

The power battery management system of this embodiment can collect the power consumption current of parts other than the CSCs through the second collection module 16, that is, the size of the input current of the BMU1, and the hardware design characteristics of the second DC/DC determine the second When the DC/DC is loaded, the output current is constant, and finally supplies power to BMU1. Therefore, dividing the input current of BMU1 by the output current of the second DC/DC can obtain the number of second DC/DCs needed, and each second DC/DC corresponds to a power battery module, and the number M of power battery modules that need to generate electricity can be obtained further. In order to ensure the normal operation of the power battery management system, the power generation capacity of the selected power battery module should be greater than the required total power generation capacity. Therefore, after calculating M, M+1 power battery modules should be controlled to provide power.

Specifically, the control module 17 generates control instructions according to the M+1 power battery modules selected by the acquisition module 13, and sends control instructions to the CSC corresponding to the M+1 power battery modules through the second communication module 11, and the CSC receives the signal Afterwards, the MCU controls to open or close the first switch Kp, and when the M+1 power battery modules selected by the module 13 are obtained, the MCU in the CSC corresponding to the M+1 power battery modules controls to close the first switch Kp to make the first switch Kp The second DC/DC works to realize that the second DC/DC takes power from M+1 power battery modules and supplies power to the Load (CSU, IMM) of the power battery management system.

The power battery management system of this embodiment collects the OCV in the corresponding power battery module through the first acquisition module in each CSC, and sends it to the BMU1, and the BMU1 calculates the M power battery modules that need to generate electricity, and Control M+1 power battery modules from large to small to supply power to CSC31 and BMU1, etc., realize the priority discharge of power battery modules with higher power generation capacity, and balance the power generation capacity among power battery modules. Adopting the technical solution of this embodiment can improve the performance of the power battery module and the service life of the power battery module.

Further, in the power battery management system of the above embodiment, the BMU1 may further include a timer 18 . The timer 18 is used to set the time period. When the power supply time of M+1 power battery modules reaches the time period, the timer 18 triggers the acquisition module 13 to start, and the acquisition module 13, the comparison module 14 and the calculation module 15 re-determine the number of power battery modules that need to generate electricity For details, reference may be made to the relevant records of the acquisition module 13, the comparison module 14, and the calculation module 15 in the above-mentioned embodiments, so as to realize re-determining the number of power battery modules that need to generate electricity, and details will not be repeated here.

In order to ensure that the power generation capacity of all power battery modules is 0, the control module 17 cannot only control M+1 power battery modules to supply power. For the SoC of the power battery module, re-compare the size of each SoC, re-determine the power generation capacity and the number of power battery modules that need to generate electricity, and always control the power battery module with a higher power generation capacity to generate electricity first, until all the power battery modules The generating capacity is 0.

However, when the power generation capacity of all power battery modules is 0, it does not mean that the actual SoC of the power battery modules is 0. At this time, it only means that the SoC of all power battery modules is the same. If it is necessary to continue to supply power to the BMS, continue powered by. Every cycle, the number of power battery modules is recalculated until the actual SoC of the power battery modules is 0, which means that all the power battery modules have been discharged and need to be charged.

It should be noted that the selected SoC(x)min can always be used as a reference value, but when Cap(x)=0 and continues to generate electricity, the obtained Cap(x) is a negative value. At this time, the absolute value needs to be taken, and then Re-determine the number of power battery modules that need to be powered. At special moments, such as the initial stage of power-on or before the external relay control is closed, it can control the power supply of all power battery modules. After a certain time delay, return to the above normal control logic.

Fig. 6 is a flow chart of an embodiment of the power supply control method of the power battery management system of the present invention. Power supply method, the power battery power supply method of this embodiment may include the following steps:

101. Obtain the remaining power of each power battery module according to the correspondence table between the OCV and the SoC of each power battery module;

For the power battery module, its OCV and SoC are in one-to-one correspondence, and the corresponding relationship table can be stored in the BMU in advance. When the CSC collects the OCV of each power battery module and sends it to the BMU, the BMU can look up the table to obtain the size of the SoC of each power battery module, which is recorded as SoC(x).

102. Compare the size of the SoC of each power battery module to obtain the smallest SoC;

Comparing the obtained SoC(x) to get the minimum SoC(x), denoted as SoC(x)min.

103. According to the minimum SoC, calculate the difference between the SoC of other power battery modules and the minimum SoC;

Use mathematical formulas to obtain the difference between SoC(x) and SoC(x)min of other power battery modules, which is recorded as ΔSoC(x).

104. Calculate the power generation capacity of each power battery module according to the difference between the SoC of other power battery modules and the smallest SoC;

Multiply ΔSoC(x) by the nominal capacity of the total batteries in each power battery module to obtain the power generation capacity of each power battery module, which is denoted as Cap(x).

105. According to the power generation capacity of each power battery module, sort each power battery module according to the power generation capacity from large to small;

Sort the obtained Cap(x) from large to small.

106. Collect the magnitude of the input current of each power battery management unit;

107. Obtain the magnitude of the input current of each power battery management unit, and calculate the number M of power battery modules that need to generate electricity;

The power battery management system can collect the power consumption current of parts other than the CSC, that is, the size of the input current of the BMU, and the current output by the power battery module through the second DC/DC is constant, so divide the input current of the BMU by the first The output current of the two DC/DCs can be used to obtain the required number of second DC/DCs, and each second DC/DC corresponds to a power battery module, and further the number M of power battery modules that need to generate electricity can be obtained. 108. According to the calculated M power battery modules, select M+1 power battery modules in descending order from the power battery modules sorted from large to small in power generation capacity to supply power;

109. Control M+1 power battery modules to supply power.

In order to ensure the normal operation of the BMS system, the total power generation of the selected power battery modules should be greater than the total power consumption of parts other than the CSC. Therefore, after calculating M, M+1 power battery modules should be controlled to provide power.

In the method for controlling the power supply of the power battery in this embodiment, the OCV of each power battery module is collected and sent to the BMU, and the BMU calculates the number M of the power battery modules that need to generate electricity, and controls them in order from large to small M+1 power battery modules supply power to components other than CSC, realizing the priority discharge of power battery modules with higher power generation capacity, and balancing the power generation capacity among power battery modules. Adopting the technical solution of this embodiment can improve the performance of the power battery module and the service life of the power battery module.

Further, the method for controlling the power supply of the power battery in the above-mentioned embodiment is described. After controlling M+1 power battery modules to supply power, the method further includes:

When the power supply time of the M+1 power battery modules reaches a preset time period, re-determine the number of power battery modules that need to generate electricity.

The preset time period is set in advance. When the power supply time of M+1 power battery modules reaches the time period, the BMU recalculates Cap(x), updates Cap(x), and re-determines the capacity of the power battery modules that need to generate electricity. quantity. For details, reference may be made to relevant records of steps 101-108 in the foregoing embodiments, and details are not repeated here.

When Cap(x)=0, it does not mean that the actual SoC of the power battery module is 0. At this time, it only means that the SoC of all power battery modules is the same. If it is necessary to continue to supply power to the BMS, continue to supply power. Every cycle, the number of power battery modules is recalculated until the SoC of the power battery modules is 0, which means that all the power battery modules have been discharged and need to be charged.

It should be noted that the selected SoC(x)min can always be used as a reference value, but when Cap(x)=0 and continues to generate electricity, the obtained Cap(x) is a negative value. At this time, the absolute value needs to be taken, and then Re-determine the number of power battery modules that need to be powered. At special moments, such as the initial stage of power-on or before the external relay control is closed, it can control the power supply of all power battery modules. After a certain time delay, return to the normal control logic.

Fig. 7 is a flow chart of another embodiment of the power supply control method of the power battery management system of the present invention. As shown in Fig. 7, the power supply method of the power battery in this implementation is specifically the power battery management system of the embodiment shown in Fig. 2 power supply, the power battery power supply method of this embodiment may include the following steps:

201. Collect the power of each battery cell in each power battery module;

202. Determine whether the power of each battery cell is greater than the preset battery power value;

203. When the power of the battery cell is greater than the preset power value of the battery cell, control the power of the corresponding battery cell to transfer to the corresponding power battery module;

204. When the power of the battery cell is less than the preset power value of the battery cell, control the power of the corresponding power battery module to transfer to the corresponding battery cell.

Specifically, BMU1 can be set with a preset battery power value. After the CSC works normally, BMU1 asks the CSC to collect the power of each battery in the Module and report it to BMU1; then BMU1 judges whether the power of each battery is greater than the preset value. Set the battery power value. When the power of the existing battery is greater than the preset battery power value, the BMU sends a control signal to the CSC. After the CSC receives the signal, the MCU in the CSC controls and closes the corresponding second switch. The power is transferred to the power battery module through the third DC/DC. When the power of the existing battery is less than the preset power value of the battery, the power of the power battery module is transferred to the power battery module through the third DC/DC. Cell transfer.

The power supply method of the power battery in this embodiment, by collecting the power of each battery cell in each power battery module, when the voltage of the battery cell in each power battery module is greater than or less than the preset battery power value, the power of the battery cell is realized. The power transfer between the power battery module and the power battery module balances the power of each cell in the power battery module and improves the performance of the power battery module. Adopting the technical solution of this embodiment can improve the performance of the power battery module and the service life of the power battery module.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above method embodiments can be completed by program instructions and related hardware. The foregoing program can be stored in a computer or a readable storage medium. When the program is executed, it executes the steps including the above-mentioned method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (11)

1. A power battery management system, characterized in that the system includes a power battery management unit, a plurality of power battery modules, and a power battery monitoring unit corresponding to each of the power battery modules; The power battery monitoring unit includes a first DC step-down power supply module and a second DC step-down power supply module; the input terminals of the first DC step-down power supply module and the second DC step-down power supply module are all connected to the corresponding The positive and negative poles of the power battery module are connected to get electricity from the power battery module; The output end of the first DC step-down power supply module is connected to the corresponding input end of the power battery monitoring unit for supplying power to the power battery monitoring unit; the output end of the second DC step-down power supply module It is connected with the input end of the power battery management unit, and is used for supplying power to the power battery management unit. 2. The system according to claim 1, wherein the power battery monitoring unit further includes a third DC step-down power supply module, one end of the third DC step-down power supply module is connected to the corresponding power battery module The positive and negative poles of each battery cell in the group are connected, and the other end is connected to the positive and negative poles of the corresponding power battery module; when the power value of the battery cell is greater than the preset power value of the battery cell, the third The DC step-down power supply module takes power from the corresponding battery cell and transfers the power to the corresponding power battery module; when the power value of the battery cell is less than the preset battery power value, the The third DC step-down power supply module takes power from the corresponding power battery module, and transfers the power to the corresponding battery cell. 3. The system according to claim 2, wherein the power battery monitoring unit further comprises a first switch, and the first switch is set between the second DC step-down power supply module and the power battery management unit In between, the first switch is used to control the second DC step-down power supply module to supply power to the power battery management unit. 4. The system according to claim 3, wherein the power battery monitoring unit further includes a second switch corresponding to each of the battery cells, and each of the second switches is set at the third DC step-down Between the power supply module and the corresponding battery cell, the second switch is used to control the energy interaction between the corresponding power battery module and the battery cells in the power battery module. 5. The system according to claim 4, wherein the power battery monitoring unit further comprises a first collection module; the first collection module is used to collect the corresponding parameter information of the power battery module, the The parameter information includes the open circuit voltage of the power battery module and the electric quantity of each battery cell. 6. The system according to claim 5, wherein the power battery monitoring unit further includes a first communication module, the power battery management unit includes a second communication module, and the first communication module is connected to the second communication module. Two communication modules are connected in communication; the first communication module is also connected to the first acquisition module; The first communication module is configured to obtain the parameter information from the acquisition module, and send the parameter information to the second communication module; the second communication module is configured to receive the parameter information. 7. The system according to claim 6, wherein the power battery management unit further comprises a storage module, an acquisition module, a comparison module, a calculation module, a second acquisition module and a control module; The storage module is used to store the corresponding relationship table between the open circuit voltage and the remaining power of each of the power battery modules; The acquisition module is connected to the storage module and the second communication module respectively, and is used for according to the correspondence table stored by the storage module and all the parameters in the parameter information received by the second communication module. The open circuit voltage is used to obtain the size of the remaining power of each of the power battery modules; The comparison module is connected to the acquisition module, and is used to compare the remaining power of each of the power battery modules according to the size of the remaining power of each of the power battery modules acquired by the acquisition module. size, to get the minimum remaining power; The calculation module is connected to the comparison module, and is used to calculate the difference between the remaining power of each of the other power battery modules and the minimum remaining power according to the minimum remaining power obtained by the comparison module. difference; and calculate the generating capacity of each of the power battery modules according to the difference; The comparison module is also used to sort each of the power battery modules according to the power generation capacity from large to small; The second collection module is used to collect the magnitude of the input current of each of the power battery management units; The calculation module is also connected to the second collection module, and is also used to obtain the magnitude of the input current of the power battery management unit, and calculate the number M of the power battery modules that need to generate electricity; The acquisition module is also connected to the calculation module, and is also used to compare the power battery modules according to the power generation capacity according to the M power battery modules calculated by the calculation module and the comparison module. According to the sorting results from large to small, M+1 power battery modules are sequentially selected from among the power battery modules sorted from large to small in power generation capacity to supply power; The control module is respectively connected to the second communication module and the acquisition module, and is used to send instructions through the second communication module according to the M+1 power battery modules selected by the acquisition module, Control the M+1 power battery modules to supply power. 8. The system according to claim 7, wherein the power battery management unit further includes a timer; the timer is used to set a time period; when the M+1 power battery modules When the power supply time reaches the time period, the timer triggers the acquisition module to start, and the acquisition module, the comparison module and the calculation module re-determine the number of the power battery modules that need to generate electricity. 9. A power supply control method for a power battery management system according to any one of claims 1-8, characterized in that the method comprises: According to the corresponding relationship table between the open circuit voltage and the remaining power of each power battery module, the size of the remaining power of each power battery module is obtained; Comparing the size of the remaining power of each of the power battery modules to obtain the smallest remaining power; According to the minimum remaining power, calculate the difference between the remaining power of each of the other power battery modules and the minimum remaining power; calculating the generating capacity of each of the power battery modules according to the difference; According to the power generation capacity of each of the power battery modules, sort each of the power battery modules according to the power generation capacity from large to small; Collect the magnitude of the input current of each power battery management unit; Obtain the magnitude of the input current of each of the power battery management units, and calculate the number M of the power battery modules that need to generate electricity; According to the calculated M power battery modules, select M+1 power battery modules in descending order from each of the power battery modules sorted from large to small in power generation capacity to supply power ; Control the M+1 power battery modules to supply power. 10. The method according to claim 9, wherein after controlling the M+1 power battery modules to supply power, the method further comprises: When the power supply time of the M+1 power battery modules reaches a preset time period, re-determine the number of the power battery modules that need to generate electricity. 11. The method according to any one of claims 9 or 10, wherein the power supply control method adopted in each of the power battery modules includes: Collect the power of each cell in each of the power battery modules; judging whether the power of each battery cell is greater than the preset battery power value; When the electric quantity of the battery cell is greater than the preset battery electric quantity value, control the electric quantity of the corresponding electric cell to be transferred to the corresponding power battery module; When the electric quantity of the battery cell is less than the preset battery electric quantity value, the electric quantity of the corresponding power battery module is controlled to be transferred to the corresponding electric cell.