WO2023169091A1

WO2023169091A1 - Battery system, control method for battery system, device, and storage medium

Info

Publication number: WO2023169091A1
Application number: PCT/CN2023/073742
Authority: WO
Inventors: 陈新伟; 李向涛; 蔡金博; 娄其栋; 李春晖
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-03-07
Filing date: 2023-01-29
Publication date: 2023-09-14
Also published as: CN116780676A

Abstract

The present application discloses a battery system, a control method for a battery system, a device, and a storage medium. The battery system comprises a main control module and a plurality of battery cells connected in parallel. Each battery cluster comprises a plurality of batteries connected in series, and a first end of each battery cluster is connected to a first common node. A first output end of each DC/DC conversion module is connected to a second end of each battery cluster, and a second output end of each DC/DC conversion module is connected to a second common node. The main control module is used for determining some of the battery clusters according to state-of-charge values during charging or discharging, and controlling some of the DC/DC conversion modules to perform current control, so as to reduce a difference in the state-of-charge values between the battery clusters. The main control module is further used for short-circuiting some of the DC/DC conversion modules when the state-of-charge values are balanced.

Description

Battery system, battery system control method, equipment and storage medium

Cross-references to related applications

This application claims priority to Chinese patent application 202210221824.6 titled "Battery system, battery system control method, equipment and storage medium" submitted on March 7, 2022. The entire content of this application is incorporated herein by reference. .

Technical field

The present application relates to the field of battery management technology, and in particular, to a battery system, a battery system control method, equipment and a storage medium.

Background technique

In battery system solutions in related technologies, multi-cluster battery clusters are usually connected in direct parallel connection and connected with the DC/AC (Direct Current/Alternating Current, DC/AC) converter and PCS (Power Conversion System) at the output end. energy storage converter) or load connection.

Due to the differences in battery cell capacity, battery cluster internal resistance and other factors among multiple battery clusters, the SOC (state of charge, state of charge) of different battery clusters when connected in parallel, that is, the remaining power exists difference. When the SOC of a certain battery cluster is significantly different from that of other battery clusters, it will cause the battery cluster to reach the discharge cut-off state or charge cut-off state in advance, thus affecting the charge and discharge operations of multiple battery clusters.

In order to avoid significant differences between the SOC of one battery cluster and other battery clusters, a DC/DC (Direct Current/Direct Current, DC/DC) converter is usually installed in series with each battery cluster to balance the SOC of each battery cluster. Avoid large differences. However, the DC/DC converter will generate power transmission losses during operation, resulting in a greatly reduced operating efficiency of the battery system.

Contents of the invention

Embodiments of the present application provide a battery system, a battery system control method, equipment and a storage medium, which can solve the technical problem of large power loss when setting up a DC/DC converter to balance SOC.

In a first aspect, embodiments of the present application provide a battery system. The battery system includes a main control module and a plurality of battery units connected in parallel. The battery units include battery clusters and DC/DC conversion modules;

The main control module is used to determine some battery units based on the state-of-charge value of each battery cluster and transfer some of the batteries to The battery clusters in the battery unit are connected in series with the DC/DC conversion module;

The main control module is also used to control the DC/DC conversion module to adjust the charging current or discharging current of the corresponding battery cluster to reduce the difference in state-of-charge values between each battery cluster.

By setting up the DC/DC conversion module, the state-of-charge value of the battery cluster in each battery unit can be obtained when the battery system is charging or discharging, and some battery clusters can be determined from multiple battery clusters based on the size of the state-of-charge value. , and connect this part of the battery cluster 11 and the corresponding DC/DC conversion module 12 in series. By sending control instructions to the DC/DC conversion module corresponding to this part of the battery cluster, the main control module can control the DC/DC conversion module to perform current control on the charging current or discharging current of its branch. By adjusting the charging current or discharging current of the branch where some of the battery clusters are located among multiple battery clusters, the state-of-charge value of this part of the battery cluster can gradually approach the state-of-charge value of other battery clusters during the charging or discharging process. , that is, reducing the difference in state-of-charge values between battery clusters.

According to some embodiments of the present application, the battery cluster includes a plurality of batteries connected in series, and the first end of the battery cluster is connected to the first common node;

The first output end of the DC/DC conversion module is connected to the second end of the battery cluster, the second output end of the DC/DC conversion module is connected to the second common node; the first input end of the DC/DC conversion module is connected to the second end of the battery cluster. The first terminal is connected, and the second input terminal of the DC/DC conversion module is connected to the second terminal of the battery cluster.

By setting the battery cluster and the DC/DC conversion module to be connected to the first common node and the second common node respectively, the battery cluster and the DC/DC conversion module can be connected in series and then connected in parallel with other battery units, thereby realizing multiple battery units. are connected in parallel to each other.

According to some embodiments of the present application, the main control module is also used to short-circuit the first output terminal and the second output terminal of some DC/DC conversion modules when the difference in state-of-charge values between each battery cluster meets the balancing condition. .

Through the main control module, when the difference in state-of-charge values between each battery cluster meets the equilibrium condition, the two output terminals of the DC/DC conversion module in the running state can be short-circuited to enable the DC/DC conversion of this part. The module stops running to reduce the power loss of the DC/DC conversion module, save the power consumption of the battery system, and improve the output efficiency of the battery system.

According to some embodiments of the present application, the battery unit further includes:

Bypass switch, the first end of the bypass switch is connected to the first output end of the DC/DC conversion module, the second end of the bypass switch is connected to the second output end of the DC/DC conversion module, and the control end of the bypass switch Connect to the bypass control terminal of the DC/DC conversion module;

The main control module is used to send bypass instructions or load operation instructions to the DC/DC conversion module, so that the DC/DC conversion module controls the bypass switch to turn on according to the bypass instruction or controls the bypass switch to turn off according to the load operation instruction. open.

By setting the bypass switch, the output end of the DC/DC conversion module can be short-circuited when the bypass switch is turned on, so that the battery cluster can be directly connected in parallel with other battery units and reduce the operating power consumption of the DC/DC conversion module.

According to some embodiments of the present application, the main control module is also used to send voltage adjustment instructions to the DC/DC conversion module according to the battery cluster voltage of the battery cluster in each battery unit, so that the total output voltage of the branch where each battery unit is located Stay balanced.

The DC/DC conversion module controls the on and off of the bypass switch, so that the DC/DC conversion module can control the bypass switch to be on or off when receiving the bypass command or load operation command sent by the main control module. On, the battery cluster is directly connected in parallel with other battery units and the battery cluster is connected in series with the DC/DC conversion module and then connected in parallel with other battery units.

Branch circuit switch, the branch circuit switch is connected in series with the battery cluster, and the branch circuit switch is disconnected before charging or discharging;

The main control module is also used to send voltage adjustment instructions to each DC/DC conversion module before charging or discharging, and to control the branch switch conduction of each battery unit when the total output voltage of the branch where each battery unit is located remains balanced. .

The main control module can obtain the battery cluster voltage of each battery cluster when the battery system is running. When there is a large difference between the voltages of each battery cluster, the DC/DC conversion module needs to be started to pass the output of the DC/DC conversion module. The voltage compensates the battery cluster voltage so that the total output voltage between each battery unit remains balanced and avoids the influence of circulating current between each battery unit. However, due to the extra power loss in the DC/DC conversion module during voltage adjustment, the main control module can also control a battery cluster when the voltage of a certain battery cluster is consistent or close to the voltage of other battery clusters. The two output terminals of the corresponding DC/DC conversion module are short-circuited, so that the battery cluster is directly connected in parallel with other battery units. At this time, the DC/DC conversion module does not provide output voltage, which can reduce the operating loss of the DC/DC conversion module.

In the second aspect, embodiments of the present application provide a battery system control method, which is applied to the main control module of the above-mentioned battery system, including:

When the battery system is charging or discharging, obtain the state-of-charge value of the battery cluster in each battery unit;

Determine some battery clusters based on the state-of-charge value of each battery cluster;

Control some DC/DC conversion modules corresponding to some battery clusters to perform current control on the charging current or discharging current to reduce the difference in state-of-charge values between each battery cluster during the charging or discharging process;

When the state-of-charge values of each battery cluster reach equilibrium, the first output terminal and the second output terminal of some DC/DC conversion modules are short-circuited.

By setting the main control module, the state-of-charge value of each battery cluster can be detected, and a part of the battery clusters can be determined based on the state-of-charge value of each battery cluster. By controlling the DC/DC conversion module corresponding to this part of the battery cluster, it is possible to The charging current or discharging current of this part of the battery cluster is current controlled to adjust the charging speed or discharging speed of this part of the battery cluster. By adjusting some of the multiple battery clusters, the difference in state-of-charge values between battery clusters can be reduced, so that the state-of-charge values of each battery cluster are gradually balanced during the charging or discharging process. When the main control module determines that the state-of-charge values of each battery cluster are balanced, the switch can be The output end of the DC/DC conversion module that is in operation is short-circuited to switch the DC/DC conversion module out of the running state, thereby reducing the power loss of the DC/DC conversion module, saving battery system power consumption, and improving the battery system. output efficiency.

According to some embodiments of the present application, determining some battery clusters based on the state-of-charge value of each battery cluster includes:

Select a preset number of battery clusters according to the state-of-charge value of each battery cluster from high to low;

Controlling some DC/DC conversion modules corresponding to some battery clusters to perform current control on the charging current or discharging current to reduce the difference in state-of-charge values between each battery cluster during the charging or discharging process includes:

When the battery system is charging, control the DC/DC conversion modules corresponding to the preset number of battery clusters to open the bypass switches and reduce the charging current of the branch;

When the battery system is discharging, the DC/DC conversion modules corresponding to the preset number of battery clusters are controlled to open the bypass switches and increase the discharge current of the branch.

After the main control module determines some battery clusters with higher power from multiple battery clusters, it can reduce the charging current of this part of the battery cluster during the charging process, so that its charging speed is reduced relative to the battery cluster with lower power. , thereby pulling in the power difference between battery clusters. The main control module can also increase the discharge current of this part of the battery cluster during the discharge process, so that its discharge speed increases relative to the battery cluster with lower power, thereby reducing the power difference between the battery clusters.

According to some embodiments of the present application, when the state-of-charge values of each battery cluster reach equilibrium, after short-circuiting the first output terminal and the second output terminal of some DC/DC conversion modules, the method further includes:

Determine the battery cluster whose state-of-charge value meets the cut-off condition as the cut-off battery cluster;

Reduce the total operating power according to the current operating power of the cut-off battery cluster;

Reduce the battery cluster current of the cut-off battery cluster until the battery cluster current of the cut-off battery cluster reaches the safe current range, and then disconnect the branch switch corresponding to the battery unit where the cut-off battery cluster is located.

When the battery cluster meets the cut-off condition, the main control module can control the cut-off battery cluster to safely disconnect, and reduce the total operating power to allow other battery clusters to continue charging or discharging, so that each battery cluster can reach full charge or full discharge status. .

According to some embodiments of the present application, when the battery system is charging or discharging, before obtaining the state-of-charge value of the battery cluster in each battery unit, the method further includes:

Before charging or discharging the battery system, obtain the battery cluster voltage of the battery cluster in each battery unit;

Determine the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage of each battery cluster;

Control the corresponding compensation voltage output by each DC/DC conversion module;

When the total output voltage of the branch where each battery unit is located reaches equilibrium, the branch switch of each battery unit is controlled to be turned on.

By setting up a main control module and connecting each battery cluster with the DC/DC conversion module in series, the battery cluster voltage of each battery cluster can be detected and obtained through the main control module. The main control module can determine the difference between the voltages of each battery cluster based on the battery cluster voltage of each battery cluster, and calculate the compensation voltage of the DC/DC conversion module corresponding to each battery cluster. The main control module can cause each DC/DC conversion module to output a corresponding compensation voltage by sending a voltage adjustment instruction including a compensation voltage to each DC/DC conversion module. The total output voltage of each battery unit is the sum of the battery cluster voltage and the compensation voltage. When there is a difference in the voltage of each battery cluster, by adjusting the value of the compensation voltage, the battery cluster voltage can be compensated by the compensation voltage, that is, the voltage of each battery unit The total output voltage can be maintained balanced. When the total output voltage of each battery unit remains balanced, the main control unit can control the branch switch to turn on to start the charging or discharging process. By compensating the battery cluster voltage of each battery cluster before charging or discharging, the difference in the total output voltage between each battery unit can be reduced, the internal circulation between battery units can be reduced, the environmental risk can be reduced, and the output of the battery system can be improved. efficiency.

According to some embodiments of the present application, before determining the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage of each battery cluster, the method further includes:

Determine the maximum battery cluster voltage value and the minimum battery cluster voltage value from the battery cluster voltage of each battery cluster;

When the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is greater than the preset voltage threshold, perform the following steps: determine the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage of each battery cluster;

When the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is less than or equal to the preset voltage threshold, each DC/DC conversion module is controlled to turn on the bypass switch;

When the bypass switches of each battery unit are all turned on, the branch switch of each battery unit is controlled to be turned on.

Before the battery system is powered on, the main control module can calculate the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value in each battery cluster, and determine whether to control the operation of each DC/DC conversion module based on the difference.

According to some embodiments of the present application, the compensation voltage corresponding to each DC/DC conversion module is determined according to the battery cluster voltage of each battery cluster, including:

Determine the maximum battery cluster voltage value and the battery unit corresponding to the maximum battery cluster voltage value from the battery cluster voltage of each battery cluster;

The minimum compensation voltage of the DC/DC conversion module is used as the compensation voltage of the DC/DC conversion module in the battery unit corresponding to the maximum battery cluster voltage value;

The compensation voltage of the DC/DC conversion module in each battery unit is calculated based on the difference between the battery cluster voltage of the battery cluster in each battery unit other than the battery unit corresponding to the maximum battery cluster voltage value and the maximum battery cluster voltage value.

The main control module can calculate the compensation voltage corresponding to the voltage of other battery clusters according to the maximum battery cluster voltage value corresponding to the minimum compensation voltage, and control the DC/DC conversion module to output the corresponding compensation voltage.

In a third aspect, embodiments of the present application provide a battery system control device. The battery system control device includes: a processor and a memory storing computer program instructions;

When the processor executes computer program instructions, the above battery system control method is implemented.

In a fourth aspect, embodiments of the present application provide a computer storage medium. Computer program instructions are stored on the computer storage medium. When the computer program instructions are executed by a processor, the above battery system control method is implemented.

The battery system, battery system control method, equipment and storage medium provided by the embodiments of the present application can obtain the battery information in each battery unit when the battery system is charging or discharging by setting a main control module and multiple DC/DC conversion modules. The state-of-charge value of the cluster is determined, and some battery clusters are determined from multiple battery clusters based on the size of the state-of-charge value. By sending control instructions to the DC/DC conversion module corresponding to this part of the battery cluster, the main control module can control the DC/DC conversion module to perform current control on the charging current or discharging current of its branch. By adjusting the charging current or discharging current of the branch where some of the battery clusters are located among multiple battery clusters, the state-of-charge value of this part of the battery cluster can gradually approach the state-of-charge value of other battery clusters during the charging or discharging process. , that is, reducing the difference in state-of-charge values between battery clusters. And the main control module can also short-circuit the two output terminals of the DC/DC conversion module in the running state when the difference in state-of-charge values between each battery cluster meets the equilibrium condition, so that the DC/DC converter module in this part can The conversion module stops running to reduce the power loss of the DC/DC conversion module, save the power consumption of the battery system, and improve the output efficiency of the battery system.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present application more clearly, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. Those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic circuit structure diagram of a battery system provided by an embodiment of the present application;

Figure 2 is a schematic circuit structure diagram of a battery system provided by another embodiment of the present application;

Figure 3 is a schematic circuit structure diagram of a battery system provided by another embodiment of the present application;

Figure 4 is a schematic flowchart of a battery system control method provided by an embodiment of the present application;

Figure 5 is a schematic flowchart of a battery system control method provided by another embodiment of the present application;

Figure 6 is a schematic flowchart of a battery system control method provided by yet another embodiment of the present application;

Figure 7 is a schematic flowchart of a battery system control method provided by yet another embodiment of the present application;

Figure 8 is a schematic flow chart of the pre-power-on stage and the charging and discharging starting zone stage in an embodiment of the present application;

Figure 9 is a schematic flow chart of the platform area stage in an embodiment of the present application;

Figure 10 is a schematic flow chart of the charging and discharging end zone stage in an embodiment of the present application;

FIG. 11 is a schematic structural diagram of a control device of a battery system provided by an embodiment of the present application.

In the attached picture:

10. Battery unit; 11. Battery cluster; 12. DC/DC conversion module; 13. Bypass switch; 14. Detection module; 15. Branch switch; 20. Main control module; N1, first common node; N2, The second public node.

Detailed ways

Features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be described in further detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only intended to explain the application, but not to limit the application. It will be apparent to one skilled in the art that the present application may be practiced without some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the present application by illustrating examples of the present application.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations are mutually exclusive. any such actual relationship or sequence exists between them. Furthermore, the terms "comprises," "comprises," or any other variations thereof are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also those not expressly listed other elements, or elements inherent to the process, method, article or equipment. Without further limitation, an element defined by the statement "comprising..." does not exclude the presence of additional identical elements in a process, method, article, or device that includes the stated element.

It should be noted that, as long as there is no conflict, the embodiments and features in the embodiments of this application can be combined with each other. The embodiments will be described in detail below with reference to the accompanying drawings.

In battery system solutions in the related art, multiple battery clusters are usually connected in direct parallel connection and connected to the DC/AC converter, PCS or load at the output end.

Due to differences in battery cell capacity, battery cluster internal resistance and other factors among multiple battery clusters, the remaining power SOC of different battery clusters when connected in parallel is different. When the SOC of a certain battery cluster is significantly different from that of other battery clusters, it will cause the battery cluster to reach the discharge cut-off state or charge cut-off state in advance, thus affecting the charge and discharge operations of multiple battery clusters.

In order to avoid significant differences between the SOC of one battery cluster and other battery clusters, a DC/DC converter is usually set up in series with each battery cluster to balance the SOC of each battery cluster and avoid large differences. However, the DC/DC converter will generate power transmission losses during operation, resulting in a greatly reduced operating efficiency of the battery system.

In order to solve the above technical problems, embodiments of the present application provide a battery system, a battery system control method, equipment, and a storage medium. The following first introduces the battery system provided by the embodiment of the present application.

Figure 1 shows a schematic structural diagram of a battery system provided by an embodiment of the present application. The battery system includes a main control module 20 and a plurality of battery units 10 connected in parallel. The battery unit 10 includes a battery cluster 11 and a DC/DC conversion module 12 .

The main control module 20 can obtain the state-of-charge value of each battery cluster 11 when the battery system is charging or discharging, and determine a partial number of battery clusters 11 and the battery cluster 11 from all battery clusters 11 based on the state-of-charge value of each battery cluster 11 . Part of the battery cells 10 corresponding to part of the battery cluster 11 . The main control module can connect the battery clusters 11 in this part of the battery unit 10 and the DC/DC conversion module 12 in series, and then connect the part of the battery unit 10 in parallel with other battery units 10 . That is, among the multiple battery units 10 connected in parallel, the battery clusters 11 in some battery units 10 are connected in series with the DC/DC conversion module 12 and then connected to the parallel node, and the battery clusters 11 in the remaining battery units 10 are directly connected to the parallel node. node.

The main control module 20 can send control instructions to the DC/DC conversion module 12 for some of the battery units 10 in which the battery cluster 11 and the DC/DC conversion module 12 are connected in series to control the DC/DC conversion module 12 to charge the branch where it is located. Current or discharge current for current control. The main control module 20 can perform current control by controlling some DC/DC conversion modules 12 when the state-of-charge values of each battery cluster 11 are different during the charging or discharging process, so that the charging speed or discharging speed of some battery clusters 11 changes. changes to reduce the difference in state-of-charge values between each battery cluster 11. That is, the state-of-charge values among the battery clusters 11 are balanced.

It can be understood that the main control module 20 can control the DC/DC conversion module 12 in some battery units 10 to adjust the state-of-charge value of the battery cluster 11 in this part of the battery units 10 . This part of the battery units 10 is the battery unit 10 in which the battery cluster 11 and the DC/DC conversion module 12 are connected in series. For the battery units 10 in which the battery cluster 11 is not connected in series with the DC/DC conversion module 12, the DC/DC conversion module 12 cannot control the current of the battery cluster 11.

In this embodiment, the main control module 20 can obtain the state-of-charge value of the battery cluster 11 in each battery unit 10 when the battery system is charging or discharging, and select the state-of-charge value from multiple battery clusters 11 according to the size of the state-of-charge value. Part of the battery clusters 11 is determined, and the corresponding part of the battery clusters 11 is connected in series with the DC/DC conversion module 12 . Main control module Block 20 sends control instructions to the DC/DC conversion module 12 corresponding to the part of the battery cluster 11 to control the DC/DC conversion module 12 to perform current control on the charging current or discharging current of the branch where it is located. By adjusting the charging current or discharging current of the branch where some of the battery clusters 11 of the plurality of battery clusters 11 are located, the state-of-charge value of this part of the battery cluster 11 can gradually approach that of other battery clusters 11 during the charging or discharging process. The state-of-charge value is to reduce the difference in state-of-charge value between each battery cluster 11 .

According to some embodiments of the present application, please continue to refer to FIG. 1 , the battery cluster 11 may include a plurality of batteries connected in series, and the first end of the battery cluster 11 is connected to the first common node N1. The first output terminal of the DC/DC conversion module 12 is connected to the second terminal of the battery cluster 11 , and the second output terminal of the DC/DC conversion module 12 is connected to the second common node N2. The first input terminal of the DC/DC conversion module 12 is connected to the first terminal of the battery cluster 11 , and the second input terminal of the DC/DC conversion module 12 is connected to the second terminal of the battery cluster 11 .

In this embodiment, for a single battery unit 10, the battery cluster 11 and the DC/DC conversion module 12 may be connected in series. The two input terminals of the DC/DC conversion module 12 are respectively connected to both ends of the battery cluster 11, that is, the battery The cluster 11 can provide an input voltage to the input end of the DC/DC conversion module 12. After adjusting the input voltage, the DC/DC conversion module 12 can output a corresponding output voltage to adjust the output total of the branch where the battery unit 10 is located. Voltage. At this time, the total output voltage of the branch where the battery unit 10 is located is the sum of the voltage of the battery cluster 11 and the output voltage of the DC/DC conversion module 12 .

According to some embodiments of the present application, please continue to refer to Figure 1. When the main control module 20 performs current control through the control part DC/DC conversion module 12, it can also determine each battery cluster 11 according to the state of charge value of each battery cluster 11. The difference in state of charge values between. When the difference in state-of-charge values between each battery cluster 11 meets the balancing condition, the main control module 20 can short-circuit the first output terminal and the second output terminal of this part of the DC/DC conversion module 12 so that this part The DC/DC conversion module 12 stops current control, thereby reducing the operating time of the DC/DC conversion module 12 during the charging or discharging process and reducing the power loss caused by operation. The balancing condition may be that the state of charge value of each battery cluster 11 reaches the average of the state of charge values of all battery clusters 11, or it may be that the difference between the maximum state of charge value and the minimum state of charge value is within a predetermined value. within the setting range.

When the difference in state-of-charge values between each battery cluster 11 meets the balancing condition, the main control module 20 can short-circuit the two output terminals of the DC/DC conversion module 12 in the running state, so that the DC/DC The DC conversion module 12 stops running to reduce the power loss of the DC/DC conversion module 12, save the power consumption of the battery system, and improve the output efficiency of the battery system.

It can be understood that for a single battery unit 10, the main control module 20 converts the DC/DC conversion module 12 When the two output terminals are short-circuited, it is equivalent to directly connecting both ends of the battery cluster 11 to the first common node N1 and the second common node N2. When the two output terminals of the DC/DC conversion module 12 are not short-circuited, it is equivalent to the battery cluster 11 and the DC/DC conversion module 12 being connected in series and then connected to the first common node N1 and the second common node N2.

According to some embodiments of the present application, please refer to FIG. 2 , the above-mentioned battery unit 10 may further include a bypass switch 13 . The first end of the bypass switch 13 is connected to the first output end of the DC/DC conversion module 12, and the second end of the bypass switch 13 is connected to the second output end of the DC/DC conversion module 12. The control of the bypass switch 13 The terminal is connected to the bypass control terminal of the DC/DC conversion module 12.

The main control module 20 can send a bypass instruction or a load operation instruction to the DC/DC conversion module 12 . When receiving the bypass command, the DC/DC conversion module 12 can control the bypass switch 13 to be turned on to short-circuit the first output end and the second output end of the DC/DC conversion module 12. At this time, the DC/DC conversion The module 12 stops running, and both ends of the battery cluster 11 are directly connected in parallel with other battery units 10 . When receiving the load operation command, the DC/DC conversion module 12 can control the bypass switch 13 to open. At this time, the output terminal of the DC/DC conversion module 12 is connected in series with the battery cluster 11. The output of the battery unit 10 at this time is The voltage is the sum of the battery cluster voltage and the output voltage of the DC/DC conversion module 12 .

By controlling the on and off of the bypass switch 13 by the DC/DC conversion module 12, the DC/DC conversion module 12 can control the bypass switch when receiving the bypass command or the load operation command sent by the main control module 20. 13 is turned on or off to realize switching between the battery cluster 11 being directly connected in parallel with other battery units 10 and the battery cluster 11 being connected in series with the DC/DC conversion module 12 and then being connected in parallel with other battery units 10 .

According to some embodiments of the present application, the main control module 20 can send voltage adjustment instructions to the DC/DC conversion module 12 corresponding to the battery cluster 11 according to the battery cluster voltage of the battery cluster 11 in each battery unit 10, so that each battery The total output voltage of the branch where unit 10 is located remains balanced.

The two input terminals of the DC/DC conversion module 12 are respectively connected to both ends of the battery cluster 11, that is, the battery cluster 11 can provide input voltage for the input terminal of the DC/DC conversion module 12, and the DC/DC conversion module 12 responds to the input voltage. After voltage adjustment, a corresponding output voltage can be output to adjust the total output voltage of the branch where the battery unit 10 is located.

For any battery unit 10 , the total output voltage of the branch where it is located is the sum of the battery cluster voltage and the output voltage of the DC/DC conversion module 12 . Since each battery unit 10 is connected to the first common node N1 and the second common node N2, that is, the plurality of battery units 10 are connected in parallel with each other. In order to reduce the circulating current between each battery unit 10 when the battery units 10 are connected in parallel, the total output voltage of each battery unit 10 needs to be kept close to or consistent. When the battery cluster voltages of each battery cluster 11 are different, the total output voltage of the battery unit 10 can be adjusted by adjusting the output voltage of the DC/DC conversion module 12 . For example, in a certain battery unit 10 When the battery cluster voltage of the battery cluster 11 is lower than that of other battery clusters, the main control module 20 can determine the voltage difference between the battery cluster voltage and the voltage of other battery clusters, and provide the DC/DC conversion module of the battery unit 10 with a voltage difference value. 12 Send a voltage adjustment command to increase the output voltage of the DC/DC conversion module 12, so that the battery unit 10 increases the output voltage of the DC/DC conversion module 12 when the battery cluster voltage is low, so that the battery unit 10 The total output voltage of the battery unit 10 can be consistent with or relatively close to the total output voltage of other battery units 10 .

The main control module 20 can obtain the battery cluster voltage of each battery cluster 11 before the battery system is powered on. When there is a large difference between the voltages of each battery cluster, the DC/DC conversion module 12 needs to be started to pass the DC/DC converter. The output voltage of the DC conversion module 12 compensates the battery cluster voltage so that the total output voltage between each battery unit 10 remains balanced and avoids the influence of circulating current between each battery unit 10 . However, since the DC/DC conversion module 12 has additional power loss during the voltage adjustment process, the main control module 20 can also control a certain battery cluster when the voltage of a certain battery cluster is consistent or close to the voltage of other battery clusters. The two output terminals of the DC/DC conversion module 12 corresponding to the battery cluster 11 are short-circuited, so that the battery cluster 11 is directly connected in parallel with other battery units 10 . At this time, the DC/DC conversion module 12 does not provide an output voltage, which can reduce the operating loss of the DC/DC conversion module 12 .

When the main control module 20 determines whether there is a voltage difference between the battery cluster voltage in a certain battery unit 10 and the battery cluster voltages of other battery clusters 11, it may compare it with the battery cluster 11 with the largest battery cluster voltage among the multiple battery units 10. It can also be compared with the average value of the individual battery cluster voltages. For example, the main control module 20 can obtain the battery cluster voltage of each battery cluster 11 and determine the maximum battery cluster voltage. For other battery units 10 , according to the voltage difference between the battery cluster voltage in the battery unit 10 and the maximum battery cluster voltage, a voltage adjustment instruction can be sent to the DC/DC conversion module 12 in the battery unit 10 to achieve DC/DC conversion. The module 12 compensates the battery difference through the output voltage, so that the total output voltage of the battery unit 10 is balanced with the total output voltage of the battery unit 10 corresponding to the maximum battery cluster voltage. Furthermore, when the main control module 20 calculates the voltage difference between the battery cluster voltage of each battery cluster 11 and the maximum battery cluster voltage, if the voltage difference is small, the main control module 20 can also convert the DC voltage in the battery unit 10 to The first output terminal and the second output terminal of the /DC conversion module 12 are short-circuited. At this time, the total output voltage of the battery unit 10 is the battery cluster voltage of the battery cluster 11 . Since the voltage difference between the battery cluster voltage of the battery cluster 11 and the maximum battery cluster voltage is small, the circulation current generated between the battery unit 10 and the battery unit 10 corresponding to the largest battery cluster 11 is small and will not be affected by excessive circulation current. .

According to some embodiments of the present application, the two input terminals of the above-mentioned DC/DC conversion module 12 can be connected to two terminals of the battery cluster 11 in the same battery unit 10, so that all batteries in the battery cluster 11 can be used as The power source of the DC/DC conversion module 12. The two input terminals of the DC/DC conversion module 12 can also be connected to a battery string composed of some batteries in the battery cluster 11 connected in series, so that this part of the batteries in the battery cluster 11 can be used as a power source. In addition, the power source of the DC/DC conversion module 12 may also be battery clusters 11 in other battery units 10, additional independent batteries, supercapacitors, DC bus bars, etc.

According to some embodiments of the present application, the above-mentioned battery unit 10 may further include a branch switch 15, which is connected in series with the battery cluster 11. The branch switch 15 is in a disconnected state before the battery system is powered on for charging or discharging.

The main control module 20 can determine the compensation voltage of each DC/DC conversion module 12 according to the battery cluster voltage of each battery cluster 11 before the battery system is powered on for charging or discharging, and sends the compensation voltage to each DC/DC conversion module 12. voltage adjustment instructions. When each DC/DC conversion module 12 outputs a compensation voltage so that the total output voltage of the branch where each battery unit 10 is located remains balanced, the main control module 20 can control the branch switch 15 in each battery unit 10 to conduct, so that each The battery unit 10 starts charging or discharging.

By setting the branch switch 15, the branch switch 15 can be turned off before the battery system is powered on. The main control module 20 controls the DC/DC conversion module 12 to output the compensation voltage so that the total output voltage of the branch where the battery unit 10 is located remains balanced. Finally, the main control module 20 can control the branch switch 15 to turn on so that the battery unit 10 starts charging or discharging.

According to some embodiments of the present application, please refer to FIG. 3 , the above-mentioned battery unit 10 may further include a detection module 14 . Multiple detection terminals of the detection module 14 are respectively connected to multiple batteries in the battery cluster 11 , and signal terminals of the detection module 14 are communicatively connected to the main control module 20 .

The detection module 14 can detect the battery cluster voltage of the battery cluster 11 and send the detected battery cluster voltage to the main control module 20 .

It can be understood that the battery cluster 11 is composed of multiple batteries connected in series. The detection module 14 can also be connected to multiple detection sub-units. The detection sub-units correspond to the multiple batteries in the battery cluster 11 one-to-one. Each detection sub-unit Able to detect the battery voltage of the corresponding battery. The detection module 14 can calculate the battery cluster voltage of the battery cluster 11 based on the battery voltage detected by each detection sub-unit.

By setting the detection module 14 , the battery cluster voltage of the battery cluster 11 can be detected, so that the main control module 20 can control the corresponding DC/DC conversion module 12 according to the battery cluster voltage of each battery cluster 11 to realize the operation of each battery unit 10 The total output voltage is balanced.

According to some embodiments of the present application, the above-mentioned detection module 14 can also detect the battery of the battery cluster 11 The current of the cluster 11 and the temperature information of each battery in the battery cluster 11 are sent to the main control module 20 .

The detection module 14 can also be connected to multiple detection sub-units respectively. The detection sub-units correspond to multiple batteries in the battery cluster 11 one-to-one, and each detection sub-unit can detect the battery temperature information of the corresponding battery. The detection module 14 can detect the current of the battery cluster 11 . After receiving the battery temperature information sent by each detection subunit, the detection module 14 can send the temperature information corresponding to each battery and the current of the battery cluster 11 to the main control module 20 .

Each battery cluster 11 of the battery system is usually equipped with multiple collection systems CSC (Cell Supervisory Controller, cell management controller). Each CSC can collect the temperature information and voltage information of the corresponding battery in the battery cluster 11 For detection, each battery cluster 11 is also equipped with a cluster-level battery management system SBMU (Slave Battery Management Unit). The SBMU can communicate with each CSC to receive battery information detected by the CSC. It can be understood that the SBMU can serve as the detection module 14 and the CSC can serve as the detection subunit.

By setting the detection module 14, the current of the battery cluster 11 and the temperature of each battery in the battery cluster 11 can be detected, so that the main control module 20 obtains the status information of each battery in the battery cluster 11 and the current information of the battery cluster 11, and The corresponding DC/DC conversion module 12 is controlled according to the above information to achieve the balance of the total output voltage of each battery unit 10 and the balance of the state of charge value of each battery cluster 11 .

FIG. 4 shows a schematic flowchart of a battery system control method provided by an embodiment of the present application. The control method of the battery system is applied to the main control module of the battery system in the above embodiment. The control method of the battery system includes:

S110, when the battery system is charging or discharging, obtain the state-of-charge value of the battery cluster in each battery unit;

S120, determine some battery clusters according to the state-of-charge value of each battery cluster;

S130, control some DC/DC conversion modules corresponding to some battery clusters to perform current control on the charging current or discharging current, so as to reduce the difference in state-of-charge values between each battery cluster during the charging or discharging process;

S140: When the state-of-charge values of each battery cluster reach equilibrium, short-circuit the first output terminal and the second output terminal of some DC/DC conversion modules.

In S110, the battery system includes a main control module and multiple battery units. The multiple battery units are connected in parallel. The output end of the battery unit can be connected to a DC/AC converter, PCS or load. Each battery unit includes a battery cluster and a DC/DC conversion module. The input terminal of the DC/DC conversion module is connected in parallel with the battery cluster, and the output terminal is connected with Cell clusters are connected in series. That is, the battery cluster can provide an input voltage to the DC/DC conversion module, and the DC/DC conversion module can generate a corresponding output voltage after adjusting the input voltage. The main control module can obtain the state-of-charge value of the battery cluster in each battery unit when the battery system is charging or discharging.

In S120, after acquiring the state-of-charge value of each battery cluster, the main control module may determine some battery clusters from the plurality of battery clusters. This part of the battery clusters may be a part of the battery clusters with a higher state of charge value, a part of the battery clusters with a lower state of charge value, or a part of the battery clusters that differs greatly from the average value of the state of charge value.

In S130, after the main control module determines the part of the battery cluster from the plurality of battery clusters, it can determine the corresponding part of the DC/DC conversion module according to the part of the battery cluster, and control the part of the DC/DC conversion module to control the charging current. Or the discharge current is controlled. During the charging or discharging process, by controlling the charging current or discharging current of a part of the battery cluster, the charging speed or discharging speed of the part of the battery cluster can be adjusted, so that the state-of-charge value of the part of the battery cluster gradually approaches state-of-charge values of other battery clusters, thereby reducing the difference in state-of-charge values between individual battery clusters. It should be noted that for battery clusters other than this part of the battery cluster, the corresponding DC/DC conversion modules have not been switched into operation.

In S140, when controlling some DC/DC conversion modules for current control, the main control module can also obtain the state-of-charge value of each battery cluster in real time, and when the state-of-charge value of each battery cluster reaches equilibrium, the state of charge value of this part The first output terminal and the second output terminal of the running DC/DC conversion module are short-circuited, so that this part of the DC/DC conversion module is cut out from the running state.

It can be understood that when the consistency of the cells in each battery cluster is high and the main control module controls part of the DC/DC conversion module to switch to operation, the difference in state-of-charge values between each battery cluster is small. By adjusting some batteries The loop current of the cluster can gradually reduce the difference in state-of-charge values between each battery cluster until the state-of-charge values of each battery cluster reach equilibrium. At this time, the main control module can control the DC/DC conversion module that is switched into operation to be switched out of the running state, so that each battery cluster can be directly connected in parallel. If the consistency of the cells in each battery cluster is poor, when the main control module controls the DC/DC conversion module to switch to operation, the state-of-charge values between each battery cluster will be greatly different. During the process, although the difference in state-of-charge values between each battery cluster can be gradually reduced, it still cannot reach a state where the state-of-charge values of each battery cluster are balanced. At this time, the main control module can short-circuit the DC/DC conversion module that is cut into operation when other cut-out conditions are met, so as to realize the cut-out of the DC/DC conversion module. For example, the cut-out condition may be that the state-of-charge value of the battery cluster enters the end range of charging and discharging, for example, the state-of-charge value reaches more than 80% during charging or 20% during discharging. the following. The cut-out condition can also be a preset adjustment time, that is, after the main control module controls the DC/DC conversion module to cut in and runs the preset adjustment time, it can control the DC/DC conversion module to cut out.

In this embodiment, by setting up the main control module, the state-of-charge value of each battery cluster can be detected, and a part of the battery clusters can be determined according to the state-of-charge value of each battery cluster, and the DC corresponding to this part of the battery cluster can be controlled. /DC conversion module can perform current control on the charging current or discharging current of this part of the battery cluster to adjust the charging speed or discharging speed of this part of the battery cluster. By adjusting some of the multiple battery clusters, the difference in state-of-charge values between battery clusters can be reduced, so that the state-of-charge values of each battery cluster are gradually balanced during the charging or discharging process. When the main control module determines that the state-of-charge values of each battery cluster are balanced, the output end of the DC/DC conversion module that is switched to operation can be short-circuited to switch the DC/DC conversion module out of the running state. Reduce the power loss of the DC/DC conversion module, save the power consumption of the battery system, and improve the output efficiency of the battery system.

According to some embodiments of the present application, please refer to Figure 5, the above S120 may include:

S210: Select a preset number of battery clusters from high to low according to the state-of-charge value of each battery cluster;

The above S130 may include:

S220, when the battery system is charging, control the DC/DC conversion modules corresponding to the preset number of battery clusters to open the bypass switches and reduce the charging current of the branch;

S230, when the battery system is discharging, control the DC/DC conversion modules corresponding to the preset number of battery clusters to open the bypass switches and increase the discharge current of the branch.

In S210, after determining the state-of-charge value of each battery cluster, the main control module may select a preset number of battery clusters in order from high to low according to the size of the state-of-charge value. The main control module can adjust the charging speed or discharging speed of the preset number of battery clusters so that the state-of-charge values of the preset number of battery clusters and other battery clusters gradually approach each other.

In S220, if the current battery system is in a charging state, the main control module can control this part of the DC/DC conversion modules to turn off the bypass switches after determining the DC/DC conversion modules corresponding to the preset number of battery clusters. Switch to operation and reduce the charging current of the branch where the preset number of battery clusters are located by adjusting the output voltage of the DC/DC conversion module.

During the charging process, after selecting some battery clusters with higher state-of-charge values from multiple battery clusters, by reducing the charging current of this part of the battery clusters, the charging speed of this part of the battery clusters can be reduced, so that the state-of-charge value The rise rate slows down. Other battery clusters with lower state-of-charge values can operate at relatively higher charge levels. Charging continues under the flow, so that the state-of-charge value gradually approaches the battery cluster that limits the charging current. That is, during the charging process, by slowing down the charging speed of the battery cluster with a higher state of charge value, the state of charge between the battery cluster with a lower state of charge value can be reduced and the battery cluster with a higher state of charge value can be reduced. value difference.

Similarly, during the discharge process, after selecting some battery clusters with higher state-of-charge values from multiple battery clusters, by increasing the discharge current of this part of the battery clusters, the discharge speed can be increased, thereby making the state-of-charge value The charge of higher battery clusters decreases rapidly, reducing the difference in state-of-charge values between battery clusters with lower state-of-charge values.

In this embodiment, after the main control module determines a part of the battery clusters with higher power from multiple battery clusters, it can reduce the charging current of this part of the battery cluster during the charging process so that its charging speed is relative to the higher power. Low battery clusters are reduced, thereby pulling in the difference in charge between battery clusters. The main control module can also increase the discharge current of this part of the battery cluster during the discharge process, so that its discharge speed increases relative to the battery cluster with lower power, thereby reducing the power difference between the battery clusters.

It can be understood that some of the battery clusters selected by the main control module from each battery cluster may also be battery clusters with a lower state of charge value. For this part of the battery cluster, the main control module controls the DC/DC conversion module to increase the charging current during the charging process to increase the charging speed of the battery cluster with a lower state of charge value and achieve a balanced state of charge value; During the discharge process, the discharge current is reduced by controlling the DC/DC conversion module to reduce the discharge speed of battery clusters with lower state of charge values and achieve balance of state of charge values.

Taking a battery system including m battery cells with a preset number of n as an example, the main control module can calculate the charging current in n battery cells with higher state-of-charge values according to the following formula when in charging state:

I1=α*(total current-(m-n)*maximum allowable current of a single cluster)/n;

Among them, α is a preset safety margin, which can be 0.95, for example. That is, the main control module needs to maintain the charging current of other battery units other than the determined n battery units at the highest allowable current under the premise that the total current remains unchanged. The charging current of the n battery units is based on the highest allowable current of other battery units. The allowable current is calculated as the residual current after apportioning the total current. After calculating the charging current I1 corresponding to the n battery units, the main control module can send a first current limit instruction including I1 to the DC/DC conversion module of the n battery units, so that the n battery units use I1 current Constant current operation. It can be understood that at this time, the battery clusters in other battery units with lower state-of-charge values maintain the highest allowable charging current, and the charging speed is faster than the battery clusters in n battery units, so that the charges of other battery clusters The state-of-charge values are close to the state-of-charge values of the n battery cells, so that the state-of-charge values of each battery cluster gradually approach each other in the charging state.

It can be understood that when controlling the DC/DC conversion module to switch into operation and keeping the charging current of the branch where the battery unit is located at I1, I1 should be smaller than the charging current of the branch where the battery unit is located when the DC/DC conversion module is not switched into operation. , so that the DC/DC conversion module can reduce the charging speed of this part of the battery cluster when it switches to operation.

Similarly, in the discharge state, the main control module calculates the discharge current in the n battery cells with higher state of charge values according to the following formula:

I2=α*maximum allowable current of a single cluster;

That is, on the premise that the total current remains unchanged, the main control module can send a second current limit instruction including I2 to the n battery units, so that the n battery units operate with a constant current of I2. It can be understood that at this time, the n battery cells are being discharged at the maximum allowable discharge current, and their state of charge values decrease faster than other battery cells with lower state of charge values. Therefore, by controlling the battery cells with higher state of charge values, The battery cells are rapidly discharged, so that the state-of-charge values of each battery cluster gradually approach each other in the discharged state.

It can be understood that when controlling the DC/DC conversion module to switch into operation and keeping the discharge current of the branch where the battery unit is located at I2, I2 should be greater than the discharge current of the branch where the battery unit is located when the DC/DC conversion module is not switched into operation. , so that the DC/DC conversion module can increase the discharge speed of this part of the battery cluster when switching to operation.

According to some embodiments of the present application, please refer to Figure 6. After the above S140, it may also include:

S310, determine the battery cluster whose state-of-charge value meets the cut-off condition as the cut-off battery cluster;

S320, reduce the total operating power according to the current operating power of the cut-off battery cluster;

S330: Reduce the battery cluster current of the cut-off battery cluster until the battery cluster current of the cut-off battery cluster reaches a safe current range, and then disconnect the branch switch corresponding to the battery unit where the cut-off battery cluster is located.

The main control module can control some DC/DC conversion modules to perform current control so that the state-of-charge values of each battery cluster are balanced, and short-circuit the output terminals of this part of the DC/DC conversion module to achieve DC/DC conversion. Module cut out. After all the DC/DC conversion modules that have been switched to operation are cut out, the battery system will enter the charge and discharge end zone while continuing to charge or continue discharging. For example, the state of charge value of the battery cluster reaches more than 80% during charging, or When the state-of-charge value reaches below 20% during discharging, each battery cluster will reach the cut-off condition of charging or discharging while continuing to charge or discharge.

In S310, in the charging and discharging end zone, the main control module detects the state-of-charge value of each battery cluster, and when the state-of-charge value of a certain battery cluster meets the cut-off condition, the battery cluster can be determined as a cut-off battery. cluster. Wherein, the state-of-charge value satisfying the cut-off condition means that the state-of-charge value of the battery cluster reaches 100% during the charging process or the state-of-charge value of the battery cluster reaches 0% during the discharging process. The cutoff condition may also be that the battery cluster voltage reaches an upper limit voltage value during charging, for example, 3.65V; or that the battery cluster voltage reaches a lower limit voltage value, such as 2.8V during discharging. That is, the cut-off condition may be a triggering condition for the battery cluster to exit charging and discharging during the charging and discharging process.

When the main control module detects that a certain battery cluster meets the cut-off condition, it can request to reduce the total operating power, and after reducing the total operating power, adjust the cut-off cluster according to whether the current state is charging or discharging.

In S320, after determining the cut-off battery cluster, the main control module can adjust the total operating power according to the current operating power of the cut-off battery cluster to reduce the total operating power. For example, after determining the shutdown battery cluster, the main control module can determine the number of battery clusters that are still running. If the number of battery clusters that are still running is X, the main control module can reduce the total operating power by 1/X.

In S330, after reducing the total operating power according to the number of remaining operating battery clusters, the main control module can reduce the battery cluster current of the cut-off battery cluster until the battery cluster current of the cut-off battery cluster is reduced to a safe current range. , the main control module can control the branch switch corresponding to the battery unit where the cut-off battery cluster is located to open, so that the battery unit where the cut-off battery cluster is located exits the charging and discharging process.

It can be understood that when the DC/DC conversion module in the battery unit has positive and negative voltage output capabilities, the main control module can directly control the DC/DC conversion module corresponding to the cut-off battery cluster to output the negative voltage compensation voltage to reduce the cut-off battery The battery cluster current of the cluster. When the DC/DC conversion module in the battery unit only has positive voltage output capability, the main control module can control the DC/DC conversion module of other battery units to output compensation voltage to increase the battery cluster current of other battery clusters, thereby reducing the cutoff The cluster current of the cluster.

In the process of controlling the current reduction of the cut-off cluster, the main control module can also detect whether the low-voltage end current of the DC/DC conversion module is zero. If the low-voltage end current of the DC/DC conversion module reaches or approaches zero, the DC/DC conversion module can be controlled to switch to a no-load standby state, and each cut-off cluster can be cut off in sequence until the last cluster is cut off. Optionally, the main control module can record the current bus voltage when the first cutoff cluster is cut off. During subsequent operation, if it is detected that the bus voltage is higher than the recorded voltage and the voltage difference exceeds the set threshold, such as 15V, then You can request to stop charging and discharging, and after confirming the stop, enter the power-off process to stop charging and discharging of the battery system.

When multiple battery clusters serve as cut-off clusters in turn and complete cut-off adjustment, multiple battery clusters are in a fully charged or fully discharged state; however, when the bus voltage is too high and the system stops charging and discharging early, not all battery clusters are in a state of full charge or full discharge. In a fully charged or discharged state.

According to some embodiments of the present application, after the main control module determines to cut off the battery cluster, it can also use the compensation voltage output by the DC/DC conversion module within the voltage regulation range of the DC/DC conversion module so that the battery cluster maintains 0 current. run.

In this embodiment, if the battery cluster maintains zero current operation beyond the voltage regulation range of the DC/DC conversion module, the above-mentioned method of reducing the total operating power and cutting off the battery cluster current to a safe current range is used. After the current of the cut-off battery cluster enters a safe current range, the corresponding branch switch is opened to cause the cut-off battery cluster to be disconnected.

According to some embodiments of the present application, please refer to Figure 7. Before the above S110, it may also include:

S410, before charging or discharging the battery system, obtain the battery cluster voltage of the battery cluster in each battery unit;

S420: Determine the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage of each battery cluster;

S430, controls the corresponding compensation voltage output by each DC/DC conversion module;

S440: When the total output voltage of the branch where each battery unit is located reaches equilibrium, control the branch switch of each battery unit to turn on.

In S410, after receiving the power-on request, the main control module can control the branch switch in each battery unit to turn on according to the power-on request to start charging or discharging of the battery system. Before the battery system is charged or discharged, that is, before the main control module controls the branch switch to turn on, the main control module can obtain the battery cluster voltage of the battery cluster in each battery unit.

In S420, after obtaining the battery cluster voltage of each battery cluster, the main control module can determine the compensation voltage corresponding to each DC/DC conversion module according to the voltage difference between the voltages of each battery cluster. For example, the main control module can compare the battery cluster voltage of each battery cluster with the standard battery cluster voltage, and calculate the voltage difference between each battery cluster voltage and the standard battery cluster voltage. This voltage difference is the compensation voltage of the DC/DC conversion module corresponding to each battery cluster.

In S430, after determining the compensation voltage corresponding to each DC/DC conversion module, the main control module can send a voltage adjustment instruction including the compensation voltage to each DC/DC conversion module to control each DC/DC conversion module to adjust according to the voltage. The instruction converts the voltage at the input end into a compensation voltage and then outputs it. In each battery unit, the sum of the battery cluster voltage and the compensation voltage output by the DC/DC conversion module is the total output voltage. By controlling each The voltage adjustment of the DC/DC conversion module can make the total output voltage of each battery unit consistent or relatively close, so that when each battery unit is connected in parallel, the internal circulation can be reduced and the risk of damage to the battery system can be reduced.

It can be understood that the standard battery cluster voltage may be the average value of the voltages of each battery cluster, or may be the maximum battery cluster voltage or the minimum battery cluster voltage. If the standard battery cluster voltage is the average value of each battery cluster voltage, then when the battery cluster voltage is greater than the average value, the compensation voltage output by the DC/DC conversion module is a negative voltage; when the battery cluster voltage is less than the average value, the DC/DC conversion module The output compensation voltage is a positive voltage. Therefore, when the DC/DC conversion module has positive and negative voltage output capabilities, the standard battery cluster voltage can be the average value of the voltages of each battery cluster.

If the standard battery cluster voltage is the maximum battery cluster voltage, then the voltages of other battery clusters are less than the maximum battery cluster voltage. In order to keep the total output voltage of each battery unit balanced, the DC/DC conversion modules in other battery units need to output The compensation voltage is a positive voltage, and the compensation voltage value is the difference between the maximum battery cluster voltage and the battery cluster voltage in the battery unit. Therefore, when the DC/DC conversion module only has positive voltage output capability, the standard battery cluster voltage can be the maximum battery cluster voltage, so that each DC/DC conversion module outputs a forward compensation voltage for battery clusters lower than the maximum battery cluster voltage. Perform voltage compensation.

In S440, after controlling the corresponding compensation voltage output by each DC/DC conversion module, the main control module can determine that the total output voltage of the branch where each battery unit is located has reached equilibrium, and control the branch switch of each battery unit to conduct. Each battery unit is connected in parallel and the charging or discharging process is started.

In this embodiment, by setting up a main control module and connecting each battery cluster with the DC/DC conversion module in series, the battery cluster voltage of each battery cluster can be detected and acquired through the main control module. The main control module can determine the difference between the voltages of each battery cluster based on the battery cluster voltage of each battery cluster, and calculate the compensation voltage of the DC/DC conversion module corresponding to each battery cluster. The main control module can cause each DC/DC conversion module to output a corresponding compensation voltage by sending a voltage adjustment instruction including a compensation voltage to each DC/DC conversion module. The total output voltage of each battery unit is the sum of the battery cluster voltage and the compensation voltage. When there is a difference in the voltage of each battery cluster, by adjusting the value of the compensation voltage, the battery cluster voltage can be compensated by the compensation voltage, that is, the voltage of each battery unit The total output voltage can be maintained balanced. When the total output voltage of each battery unit remains balanced, the main control unit can control the branch switch to turn on to start the charging or discharging process. By compensating the battery cluster voltage of each battery cluster before charging or discharging, the difference in the total output voltage between each battery unit can be reduced, the internal circulation between battery units can be reduced, the environmental risk can be reduced, and the output of the battery system can be improved. efficiency.

It should be noted that if one of the multiple battery clusters in the battery system meets the cut-off condition, all battery clusters are controlled to stop charging or discharging. At this time, the voltages of each battery cluster remain consistent or relatively close. Recently, when power is turned on again for discharging or charging, the voltage difference between each battery cluster is small, and each battery cluster can be directly connected in parallel.

If a certain battery cluster in the battery system meets the cut-off condition, only the battery cluster is controlled to be disconnected, and other battery clusters continue to charge or discharge, so that each battery cluster is in a fully charged or fully discharged state at the end of charging or discharging. When the battery system is powered on again for discharging or charging, due to the consistency deviation of the cells of each battery cluster, the battery cluster voltages of each battery cluster in the fully charged or fully discharged state are greatly different. At this time, each battery cluster has a large difference in voltage. The voltage difference between battery clusters is large, and each battery cluster needs to balance the total output voltage of each branch under the compensation voltage of the DC/DC conversion module before it can be connected in parallel. That is, when all battery clusters are disconnected when the first battery cluster reaches the cut-off condition, the voltage difference between each battery cluster will be small when power is re-powered, and the battery cluster voltage does not need to be compensated; if each battery cluster reaches the If the cut-off conditions are met and disconnected one after another, the voltage difference between each battery cluster will be large when the power is turned on again, and the battery cluster voltage needs to be balanced and compensated.

According to some embodiments of the present application, before the above S420, the battery system control method may also include:

S510, determine the maximum battery cluster voltage value and the minimum battery cluster voltage value from the battery cluster voltage of each battery cluster;

When the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is greater than the preset voltage threshold, S420 is executed to determine the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage of each battery cluster;

S520, when the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is less than or equal to the preset voltage threshold, control each DC/DC conversion module to turn on the bypass switch;

S530: When the bypass switches of each battery unit are all turned on, control the branch switches of each battery unit to turn on.

In S510, the main control module may determine the maximum battery cluster voltage value and the minimum battery cluster voltage value from the battery cluster voltages of each battery cluster.

When obtaining the preset voltage threshold, the main control module can determine whether the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is greater than the preset voltage threshold. If the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is greater than the preset voltage threshold, it means that the voltage difference between each battery cluster is large. If the battery cluster voltage is not compensated, the battery cells will Due to the large pressure difference, large internal circulation occurs, causing damage to the battery cells. At this time, the main control module needs to control each DC/DC conversion module to generate the corresponding compensation voltage. To reduce the pressure difference between each battery unit, thereby reducing the impact of internal circulation. The main control module can determine the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage value of each battery cluster, so as to control each DC/DC conversion module to output the corresponding compensation voltage, so that the total output voltage of each battery unit is compensated Balance is maintained under voltage compensation.

In S520, if the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is less than or equal to the preset voltage threshold, the main control module can send a bypass instruction to each DC/DC conversion module to enable DC/DC conversion. The module controls the bypass switch to turn on and short-circuit the output end of the DC/DC conversion module so that each battery cluster can be directly connected in parallel.

The preset voltage threshold is the voltage difference corresponding to the upper limit of the internal circulating current between battery cells. When the voltage difference between battery clusters is greater than the preset voltage threshold, and the battery clusters are directly connected in parallel, the comparison A large voltage difference will lead to a large internal circulation current, which will cause damage to various components in the battery system under excessive circulation. That is, when the voltage difference between battery clusters is large, direct parallel connection between battery clusters will produce excessive circulating current, and the DC/DC conversion module output compensation voltage needs to be controlled to reduce the voltage difference between battery units, thereby making Internal circulation does not affect the internal components of the battery system.

In S530, after controlling the bypass switch of each battery unit to turn on, the main control module can control the branch switch of each battery unit to turn on, so that the battery clusters of each battery unit are directly connected in parallel.

Before the battery system is powered on, the main control module can calculate the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value in each battery cluster. If the difference is large, each DC/DC conversion module is controlled to output the compensation voltage, and then the branch switch is turned on, so that each battery cluster is connected in parallel under the compensation of the compensation voltage and then charged or discharged, thereby reducing the voltage difference between the battery clusters. Internal circulation. If the difference is small, the main control module can control each bypass switch to turn on, so that each DC/DC conversion module does not output a compensation voltage, and control each bypass switch to turn on, so that multiple battery clusters can directly Connect in parallel and start charging and discharging. While avoiding the impact of excessive internal circulation, it can also reduce the running time of the DC/DC conversion module to reduce system power consumption and improve the charging and discharging efficiency of the battery system.

Taking the preset voltage threshold of 20V as an example, if the difference is greater than 20V, it means that the voltage difference between battery clusters is large, and each DC/DC conversion module needs to output a compensation voltage for compensation. If the difference is less than or equal to 20V, the voltage difference between each battery cluster is small, and each DC/DC conversion module can be cut out of operation by turning on the bypass switch. At this time, each battery cluster is directly connected in parallel.

According to some embodiments of the present application, the above S420 may include:

S610: Determine the maximum battery cluster voltage value and the battery unit corresponding to the maximum battery cluster voltage value from the battery cluster voltage of each battery cluster;

S620, use the minimum compensation voltage of the DC/DC conversion module as the compensation voltage of the DC/DC conversion module in the battery unit corresponding to the maximum battery cluster voltage value;

S630: Calculate the compensation voltage of the DC/DC conversion module in each battery unit based on the difference between the battery cluster voltage of the battery cluster in each battery unit other than the battery unit corresponding to the maximum battery cluster voltage value and the maximum battery cluster voltage value.

In S610, when the main control module determines the compensation voltage output by each DC/DC conversion module according to the battery cluster voltage of each battery cluster, it can determine the maximum battery cluster voltage value and its corresponding battery from the battery cluster voltage of each battery cluster. unit. For other battery clusters, the main control module can determine the battery unit corresponding to the compensation voltage output by the DC/DC conversion module of the battery cluster and the maximum battery cluster voltage value based on the difference between the battery cluster voltage of the battery cluster and the maximum battery cluster voltage value. The difference in the compensation voltage output by the DC/DC conversion module.

In S620, when the DC/DC conversion module outputs the compensation voltage, the output compensation voltage is within a certain voltage range. In order to enable each other DC/DC conversion module to output appropriate compensation voltage, the main control module can set the compensation voltage output by the DC/DC conversion module in the battery unit corresponding to the maximum battery cluster voltage value to the minimum compensation voltage. When the battery cluster voltage values of other battery clusters are less than the maximum battery cluster voltage value, the compensation voltage output by the corresponding DC/DC conversion module needs to be greater than the minimum compensation voltage to compensate for the difference in battery cluster voltages.

In S630, the main control module can determine the difference between the battery cluster voltage in each battery unit and the maximum battery cluster voltage value, and use the sum of the difference and the minimum compensation voltage as the compensation of the corresponding DC/DC conversion module. Voltage. For example, if the difference between the battery cluster voltage in a certain battery unit and the maximum battery cluster voltage is 3V, and the minimum compensation voltage of the DC/DC conversion module is 5V, then the compensation voltage of the DC/DC conversion module corresponding to the battery unit The voltage is 8V, and the compensation voltage of the DC/DC conversion module corresponding to the maximum battery cluster voltage value is 5V, so that the battery cluster voltage of the battery unit is compensated by the DC/DC conversion module and corresponds to the maximum battery cluster voltage value. The total output voltage of the battery cells remains the same or relatively close. After the main control module determines the compensation voltage of each DC/DC conversion module based on the battery cluster voltage of each battery unit, the total output voltage of each battery unit can be maintained balanced under the compensation of the DC/DC conversion module.

When the DC/DC conversion module has an output range of the compensation voltage, the main control module can set the DC/DC conversion module corresponding to the maximum battery cluster voltage value to the minimum compensation voltage, according to the battery in other battery units. The difference between the cluster voltage and the maximum battery cluster voltage value determines the actual compensation voltage of each DC/DC conversion module, so that the total output voltage of each battery unit can remain balanced after being compensated by the DC/DC conversion module.

The following description takes the battery system including three battery clusters A, B and C as an example. Since the charging and discharging efficiency of each battery cluster is different during the charging and discharging process, the time for each battery cluster to reach the cut-off condition during the charging and discharging process has a certain time. That is, there are differences in the time it takes for each battery cluster to complete discharging or completing charging.

When charging and discharging, the battery cluster may sequentially include a charging and discharging starting area, a platform area, and a charging and discharging end area. The charging and discharging starting area, the plateau area and the charging and discharging end area can be divided according to the state of charge value SOC of the battery cluster. For example, the state-of-charge value SOC can be divided into 20% and 80%, or other values can be used to divide the area, which is not limited here. When divided according to 20% and 80%, if the battery cluster is in a charging state, the charging and discharging starting area, platform area and charging and discharging end area are 0-20%, 20%-80% and 80%-100% respectively; If the battery cluster is in a discharge state, the charge and discharge starting area, the plateau area, and the charging and discharging end area are 100%-80%, 80%-20%, and 20%-0 respectively.

In a battery system without a DC/DC conversion module and each battery cluster is directly connected in parallel, if a certain battery cluster reaches a reduction in charge and discharge power or reaches a cut-off condition, other battery clusters in the entire battery system will also reduce the charge and discharge power at the same time. or end at the same time. For example, when cluster A reaches the cut-off condition, even if clusters B and C fail to fully charge or discharge, the entire battery system stops the charging and discharging process because cluster A reaches the cut-off condition. At this time, neither cluster B nor cluster C reaches full charge or discharge. Fully charged or discharged state.

By arranging series-connected DC/DC conversion modules on each battery cluster, during the charging and discharging process of the three battery clusters A, B and C, the DC/DC conversion module can adjust the current of some battery clusters, so that the three battery clusters state-of-charge values remain balanced. It can be understood that due to parameter limitations of the DC/DC conversion module, the DC/DC conversion module usually balances the state-of-charge values of each battery cluster by adjusting the charging current or discharging current in the plateau area during the charging and discharging process. Through the balancing adjustment of the DC/DC conversion module, when the three battery clusters A, B and C enter the charge and discharge end zone from the platform area, the state-of-charge values of the three battery clusters A, B and C can remain consistent or relatively close. , so that when one of the three battery clusters A, B and C in the charge and discharge end zone reaches the cut-off condition, the difference in state-of-charge values between the other two battery clusters and the battery cluster that reaches the cut-off condition is reduced.

Furthermore, when one of the three battery clusters A, B and C meets the cut-off condition, by reducing the total operating power and controlling the safe disconnection of the cut-off battery cluster, the remaining battery clusters that have not reached the cut-off condition can be Continue charging or discharging until the three battery clusters A, B, and C reach full charge or full discharge, then end the charge and discharge process.

In a complete charging process, it can include four stages before power-on, charging and discharging starting area, platform area and charging and discharging end area. The following is a detailed description of the four stages.

Please refer to Figure 8. In the pre-power-on stage, the main control module receives the power-on request. At this time, the branch switch of each battery unit is in a disconnected state. The main control module can obtain the battery cluster voltage of each battery cluster, and determine whether to control the DC/DC conversion module to output a compensation voltage for compensation based on the difference in battery cluster voltage. For example, the main control module can calculate the difference between the maximum battery cluster voltage and the minimum battery cluster voltage. When the difference reaches the preset voltage threshold, it controls the DC/DC conversion module to output the compensation voltage for compensation; when the difference does not reach the preset voltage threshold, When the voltage threshold is preset, the bypass switch is controlled to be turned on and the DC/DC conversion module does not work.

After controlling each DC/DC conversion module to compensate the battery cluster voltage or controlling the bypass switch to turn on so that the battery clusters are hard to be connected in parallel, the main control module can control the branch switch of each battery unit to turn on so that each battery unit is connected in parallel. , and complete powering on.

In the initial stage of charging and discharging, the main control module can send voltage stabilization instructions to the DC/DC conversion module corresponding to the battery cluster with the highest voltage, and send current stabilization instructions to other DC/DC conversion modules. When the DC/DC conversion module receives the voltage stabilization command, it outputs the minimum compensation voltage to the battery cluster with the highest voltage. When the DC/DC conversion module receives the steady current command, the DC/DC conversion module can determine the corresponding steady current value according to the steady current command and control the current at its low-voltage end, that is, the charging current of the branch where the battery cluster is located is maintained at this steady current value. .

Before entering the platform stage, the main control module can control each DC/DC conversion module to turn on the corresponding bypass switch, so that the DC/DC conversion module can be cut out from the running state. The main control module can monitor the voltage of each battery cluster in real time during the initial stage of charging and discharging, and calculate the difference between the maximum battery cluster voltage and the minimum battery cluster voltage.

When the difference is greater than the cut-out threshold, the main control module can control each DC/DC conversion module to adjust the compensation voltage to the minimum compensation voltage when entering the platform area, and control each bypass switch to turn on according to the preset rules. Make each DC/DC conversion module cut out of operation.

When the difference is less than or equal to the cut-out threshold, the main control module can directly control each bypass switch to conduct according to the preset rules, so that each DC/DC conversion module can cut out operation.

The above-mentioned cut-out threshold can be 3V or other voltage values. When the voltage difference between the battery clusters is greater than the cut-out threshold, the main control module does not control the DC/DC conversion module to cut out until it enters the platform stage; while the voltage difference between the battery clusters is less than the cut-out threshold. When the threshold is reached, the main control module can control the DC/DC conversion module to cut out the operation in the initial stage of charging and discharging. The preset rules can be in order of the current of each battery cluster. Control the corresponding DC/DC conversion module to cut out the operation.

Please refer to Figure 9. In the platform area stage, the main control module has controlled each DC/DC conversion module to cut out operation. That is, in the early stage of the platform area stage, each battery cluster is directly connected in hard parallel. The main control module can determine whether to balance the state-of-charge values of the battery clusters based on the difference in the state-of-charge values of each battery cluster. For example, the main control module can calculate the difference between the maximum state of charge value and the minimum state of charge value. When the difference is less than the balancing threshold, the main control module may not balance the state of charge values of the battery cluster; when the difference is When it is greater than the balancing threshold, the main control module can balance the state-of-charge value of the battery cluster. The balance threshold can be 10, that is, when the difference between the maximum state of charge value and the minimum state of charge value is greater than 10, the main control module can control some DC/DC conversion modules to switch into operation to achieve balance of state of charge values.

When the difference is greater than the balancing threshold, the main control module can select some battery clusters from multiple battery clusters for balancing adjustment. This part of the battery cluster may be a battery cluster with a higher state of charge value, a battery cluster with a lower state of charge value, or a battery cluster with a larger deviation from the average value of the state of charge value.

Taking a battery cluster with a higher state of charge value as an example, after determining some battery clusters with a higher state of charge value from multiple battery clusters, the main control module can control the DC/DC conversion module corresponding to this part of the battery cluster. In this way, the DC/DC conversion module reduces the charging current of the battery cluster, thereby slowing down the charging speed of the battery cluster with a higher state of charge value, so that the state of charge values between the battery clusters gradually approach each other during the charging process.

In the platform area stage, the main control module can also calculate the real-time average value of the state of charge of each battery cluster. When the state-of-charge value of a certain battery cluster is consistent with the average value, the main control module can control the bypass switch corresponding to the battery cluster to turn on, so that the DC/DC conversion module switches out of operation. When the state-of-charge values of each battery cluster reach the average value, the main control module can sequentially control each DC/DC conversion module to switch out of operation until all DC/DC conversion modules are switched out of operation.

Please refer to Figure 10. In the end zone stage of charging and discharging, each DC/DC conversion module is cut out for operation, and each battery cluster is directly connected in parallel with each other. During the charging process in the end zone of charge and discharge, if a certain battery cluster meets the cut-off condition, the battery cluster is determined to be a cut-off battery cluster, and the total operating power is reduced according to the number of battery clusters still running. After reducing the total operating power, the main control module can control each DC/DC conversion module corresponding to the battery cluster to enter 0 current operation, and disconnect the corresponding battery cluster when the low-voltage end current of each DC/DC conversion module reduces to 0. branch switch.

When controlling each DC/DC conversion module to enter 0-current operation, if the low-voltage end current of the DC/DC conversion module drops to 0, the branch switch corresponding to the battery cluster can be controlled to open to disconnect the cut-off battery cluster. . If the low-voltage end current of the DC/DC conversion module cannot be reduced to 0 and the output power of the DC/DC conversion module does not exceed the limit, the main control module can control the branch switch to perform load disconnection. If the low-voltage end current of the DC/DC conversion module cannot be reduced to 0, and the output power of the DC/DC conversion module exceeds the limit, the main control module needs to request to stop charging and control the battery system to stop the entire machine.

When each battery cluster reaches the cut-off condition, the main control module can control the corresponding DC/DC conversion module to enter 0 current operation, and disconnect the battery cluster that reaches the cut-off condition when the current drops to 0. At this time, each battery cluster can reach a fully charged state.

After the first battery cluster reaches the cut-off condition and is disconnected when the current drops to 0, the main control module can record the current bus voltage and detect the difference between the real-time bus voltage and the recorded voltage during subsequent operation. When the difference exceeds the set threshold, for example, when the real-time bus voltage is higher than the recorded voltage and the difference reaches 15V, the main control module can control all DC/DC conversion modules to perform 0-current operation and send a power-off request to make the battery system Stop charging. When the bus voltage is too high and the system stops charging and discharging early, not all battery clusters are in a fully charged or fully discharged state.

In a complete discharge process, it can also include four stages before power-on, charging and discharging starting area, platform area and charging and discharging end area. The implementation of each stage is similar to the corresponding stages in the charging process, and will not be described again here.

Figure 11 shows a schematic diagram of the hardware structure of the control device of the battery system provided by the embodiment of the present application.

The control device of the battery system may include a processor 1101 and a memory 1102 storing computer program instructions.

Specifically, the above-mentioned processor 1101 may include a central processing unit (CPU), or an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), or may be configured to implement one or more integrated circuits according to the embodiments of the present application.

Memory 1102 may include bulk storage for data or instructions. By way of example, and not limitation, the memory 1102 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a Universal Serial Bus (USB) drive or two or more A combination of many of the above. Memory 1102 may include removable or non-removable (or fixed) media, where appropriate. Where appropriate, the memory 1102 may be internal or external to the integrated gateway disaster recovery device. In certain embodiments, memory 1102 is non-volatile solid-state memory.

Memory may include read only memory (ROM), random access memory (RAM), disk storage media physical devices, optical storage media devices, flash memory devices, electrical, optical or other physical/tangible memory storage devices. Thus, generally, memory includes one or more tangible (non-transitory) readable storage media (e.g., memory devices) encoded with software including computer-executable instructions, and when the software is executed (e.g., by one or more processor), which is operable to perform the operations described with reference to a method according to an aspect of the present disclosure.

The processor 1101 reads and executes the computer program instructions stored in the memory 1102 to implement any of the battery system control methods in the above embodiments.

In one example, the control device of the battery system may also include a communication interface 1103 and a bus 1110. Among them, as shown in Figure 11, the processor 1101, the memory 1102, and the communication interface 1103 are connected through the bus 1110 and complete communication with each other.

The communication interface 1103 is mainly used to implement communication between modules, devices, units and/or equipment in the embodiments of this application.

Bus 1110 includes hardware, software, or both, coupling components of the battery system's control equipment to each other. By way of example, and not limitation, the bus may include Accelerated Graphics Port (AGP) or other graphics bus, Enhanced Industry Standard Architecture (EISA) bus, Front Side Bus (FSB), HyperTransport (HT) interconnect, Industry Standard Architecture (ISA) Bus, Infinite Bandwidth Interconnect, Low Pin Count (LPC) Bus, Memory Bus, Micro Channel Architecture (MCA) Bus, Peripheral Component Interconnect (PCI) Bus, PCI-Express (PCI-X) Bus, Serial Advanced Technology Attachment (SATA) bus, Video Electronics Standards Association Local (VLB) bus or other suitable bus or a combination of two or more of these. Where appropriate, bus 1110 may include one or more buses. Although the embodiments of this application describe and illustrate a specific bus, this application contemplates any suitable bus or interconnection.

The control device of the battery system may be based on the above-mentioned battery system, thereby implementing the control method of the battery system described in conjunction with FIGS. 4 to 7 .

In addition, combined with the battery system control method in the above embodiments, embodiments of the present application may provide a computer storage medium for implementation. The computer storage medium stores computer program instructions; when the computer program instructions are executed by the processor, any one of the battery system control methods in the above embodiments is implemented.

The functional blocks shown in the above structural block diagram can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it may be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, or the like. When implemented in software, elements of the application are programs or code segments that are used to perform the required tasks. The program or code segment may be stored in a machine-readable medium or transmitted via a carrier wave The first data signal carried in is transmitted over the transmission medium or communication link. "Machine-readable medium" may include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, and the like. Code segments may be downloaded via computer networks such as the Internet, intranets, and the like.

It should be noted that, as used herein, the terms "include", "comprises" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article or device that includes a series of elements not only includes those elements, It also includes other elements not expressly listed or inherent in the process, method, article or equipment.

This article uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above examples is only used to help understand the method and the core idea of the present application. The above are only optional implementations of the present application. It should be pointed out that due to the limitations of written expressions, there are objectively unlimited specific structures. For those of ordinary skill in the art, without departing from the principles of the present application, , several improvements, modifications or changes can also be made, and the above technical features can also be combined in an appropriate manner; these improvements, modifications or combinations, or the concepts and technical solutions of the present application can be directly applied to other situations without improvement. , shall be regarded as the protection scope of this application.

Claims

A battery system, the battery system includes a main control module and a plurality of battery units connected in parallel, and the battery unit includes a battery cluster and a DC/DC conversion module;

The main control module is used to determine some battery units according to the state-of-charge value of each battery cluster, and connect the battery clusters in the partial battery units in series with the DC/DC conversion module;

The main control module is also used to control the DC/DC conversion module to adjust the charging current or discharging current of the corresponding battery cluster to reduce the difference in state-of-charge values between each battery cluster.
The battery system according to claim 1, wherein the battery cluster includes a plurality of batteries connected in series, and a first end of the battery cluster is connected to a first common node;

The first output end of the DC/DC conversion module is connected to the second end of the battery cluster, and the second output end of the DC/DC conversion module is connected to the second common node; The first input terminal is connected to the first terminal of the battery cluster, and the second input terminal of the DC/DC conversion module is connected to the second terminal of the battery cluster.
The battery system according to claim 1, wherein the main control module is further configured to change the first part of the DC/DC conversion module when the difference in state-of-charge values between each battery cluster satisfies the balancing condition. The output terminal and the second output terminal are short-circuited.
The battery system of claim 3, wherein the battery unit further includes:

Bypass switch, the first end of the bypass switch is connected to the first output end of the DC/DC conversion module, and the second end of the bypass switch is connected to the second output end of the DC/DC conversion module. Connect, the control end of the bypass switch is connected to the bypass control end of the DC/DC conversion module;

The main control module is used to send a bypass instruction or a load operation instruction to the DC/DC conversion module, so that the DC/DC conversion module controls the bypass switch to turn on or off according to the bypass instruction. The bypass switch is controlled to be turned off according to the load operation command.
The battery system according to claim 4, wherein the main control module is further configured to send a voltage adjustment instruction to the DC/DC conversion module according to the battery cluster voltage of the battery cluster in each of the battery units, In order to keep the total output voltage of the branch where each battery unit is located balanced.
The battery system of claim 5, wherein the battery unit further includes:

A branch switch, the branch switch is connected in series with the battery cluster, and the branch switch is in a disconnected state before charging or discharging;

The main control module is also used to send voltage adjustment instructions to each DC/DC conversion module before charging or discharging, and to control the branch circuit opening of each battery unit when the total output voltage of the branch where each battery unit is located remains balanced. Turn off.
A battery system control method, which is applied to the main control module of the battery system according to any one of claims 1 to 6, and the battery system control method includes:

When the battery system is charging or discharging, obtain the state-of-charge value of the battery cluster in each battery unit;

Determine some battery clusters based on the state-of-charge value of each battery cluster;

Control some DC/DC conversion modules corresponding to some of the battery clusters to perform current control on the charging current or the discharging current, so as to reduce the difference in state-of-charge values between the various battery clusters during the charging or discharging process;

When the state-of-charge values of each battery cluster reach equilibrium, the first output terminal and the second output terminal of the partial DC/DC conversion module are short-circuited.
The control method of a battery system according to claim 7, wherein determining some of the battery clusters according to the state-of-charge value of each battery cluster includes:

Select a preset number of battery clusters according to the state-of-charge value of each battery cluster from high to low;

The control of the partial DC/DC conversion modules corresponding to the partial battery clusters to perform current control on the charging current or the discharging current to reduce the difference in state-of-charge values between the various battery clusters during the charging or discharging process includes:

When the battery system is charging, control the DC/DC conversion modules corresponding to the preset number of battery clusters to open the bypass switches and reduce the charging current of the branch;

When the battery system is discharging, the DC/DC conversion modules corresponding to a preset number of battery clusters are controlled to open the bypass switches and increase the discharge current of the branch where they are located.
The control method of the battery system according to claim 7, wherein when the state-of-charge values of each battery cluster reach equilibrium, the first output terminal and the second output terminal of the partial DC/DC conversion module are short-circuited. After that, it also includes:

Determine the battery cluster whose state of charge value satisfies the cut-off condition as a cut-off battery cluster;

Reduce the total operating power according to the current operating power of the cut-off battery cluster;

When the battery cluster current of the cut-off battery cluster is reduced until the battery cluster current of the cut-off battery cluster reaches a safe current range, the branch switch corresponding to the battery unit where the cut-off battery cluster is located is opened.
The control method of the battery system according to claim 9, wherein before obtaining the state-of-charge value of the battery cluster in each battery unit when the battery system is charging or discharging, it further includes:

Before charging or discharging the battery system, obtain the battery cluster voltage of the battery cluster in each battery unit;

Determine the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage of each battery cluster;

Control the corresponding compensation voltage output by each DC/DC conversion module;

When the total output voltage of the branch where each battery unit is located reaches equilibrium, the branch switch of each battery unit is controlled to be turned on.
The control method of a battery system according to claim 10, wherein the power consumption of each battery cluster is Before the cell cluster voltage determines the compensation voltage corresponding to each DC/DC conversion module, it also includes:

Determine the maximum battery cluster voltage value and the minimum battery cluster voltage value from the battery cluster voltage of each battery cluster;

When the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is greater than the preset voltage threshold, perform the steps of: determining the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage of each battery cluster;

When the difference between the maximum battery cluster voltage value and the minimum battery cluster voltage value is less than or equal to the preset voltage threshold, control each DC/DC conversion module to turn on the bypass switch;

When the bypass switches of each battery unit are all turned on, the branch switch of each battery unit is controlled to be turned on.
The control method of a battery system according to claim 7, wherein determining the compensation voltage corresponding to each DC/DC conversion module according to the battery cluster voltage of each battery cluster includes:

Determine the maximum battery cluster voltage value and the battery unit corresponding to the maximum battery cluster voltage value from the battery cluster voltage of each battery cluster;

Use the minimum compensation voltage of the DC/DC conversion module as the compensation voltage of the DC/DC conversion module in the battery unit corresponding to the maximum battery cluster voltage value;

Calculate the DC/DC conversion module in each battery unit according to the difference between the battery cluster voltage of the battery cluster in each battery unit other than the battery unit corresponding to the maximum battery cluster voltage value and the maximum battery cluster voltage value. the compensation voltage.
A control device for a battery system. The control device for the battery system includes: a processor and a memory storing computer program instructions;

When the processor executes the computer program instructions, the battery system control method as claimed in claims 7 to 12 is implemented.
A computer storage medium. Computer program instructions are stored on the computer storage medium. When the computer program instructions are executed by a processor, the control method of the battery system as claimed in claims 7 to 12 is implemented.