CN115149600A - Charging and discharging control method and device and energy storage system - Google Patents

Abstract

The invention discloses a charge-discharge control method, a charge-discharge control device and an energy storage system, in the scheme, the power supply voltage of each battery is acquired in real time in the process of charging or discharging N batteries, when the batteries with the power supply voltage reaching a preset threshold exist, the batteries are judged to be unbalanced batteries, the batteries with the power supply voltage not reaching the preset threshold are judged to be balanced batteries, then a switch circuit is controlled to stop charging and discharging the unbalanced batteries and control the balanced batteries to continue the process of charging and discharging until the power supply voltages of the N batteries reach the preset threshold, all the batteries can achieve a better charging and discharging effect, the N batteries can be ensured to achieve balanced charging and discharging, and the service life of the batteries and the stability during charging and discharging are favorably improved.

Description

A charge and discharge control method, device and energy storage system

technical field

The invention relates to the field of energy storage and power supply, in particular to a charge and discharge control method, device and energy storage system.

Background technique

With the increasing demand for new energy energy storage, the energy storage method using a large number of echelon batteries has been widely used. Due to the decay of the echelon battery for a certain period of time, the capacity is reduced, the internal resistance is increased, and the performance is deteriorated. These conditions may result in a reduction in the lifespan of the echelon battery and the occurrence of unstable output.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a charging and discharging control method, device and energy storage system, which can make all batteries achieve better charging and discharging effects and ensure that N batteries can achieve balanced charging and discharging.

In order to solve the above technical problems, the present invention provides a charge and discharge control method, which is applied to a processor in an energy storage system, the energy storage system includes a switch circuit and N batteries connected in series, where N is an integer greater than 1; The methods described include:

During the charging and discharging process, obtain the power supply voltage of each battery in real time;

determine whether there is a battery with a supply voltage that reaches a preset threshold;

If there is, the battery whose power supply voltage reaches the preset threshold is determined as an unbalanced battery, and the battery whose power supply voltage does not reach the preset threshold is determined as a balanced battery;

The switch circuit is controlled to stop charging and discharging of the unbalanced battery, and continue charging and discharging of the balanced battery until the power supply voltages of the N batteries reach the preset threshold.

Preferably, the switch circuit is controlled to stop charging and discharging of the unbalanced battery, and continue charging and discharging of the balanced battery until the power supply voltages of the N batteries reach the preset threshold, including:

grouping the balanced batteries according to preset conditions;

By controlling the switch circuit, each balanced battery group is sequentially charged and discharged until the power supply voltages of the N batteries reach the preset threshold.

Preferably, after sequentially charging and discharging each balanced battery pack by controlling the switch circuit, the method further includes:

Obtain the power supply voltage of the currently charged and discharged battery, and re-enter the step of determining whether there is a battery whose power supply voltage reaches a preset threshold.

Preferably, determining whether there is a battery whose power supply voltage reaches a preset threshold includes:

During the charging process, determine whether there is a battery whose power supply voltage reaches a first preset threshold;

And, during the discharging process, it is determined whether there is a battery whose power supply voltage reaches a second preset threshold, and the first preset threshold is greater than the second preset threshold.

Preferably, the energy storage system further includes a bidirectional AC/DC module, the switch circuit includes a front-end switch group and a rear-end switch group, and the front-end switch group includes N front-end switches corresponding to the N batteries. , the back-end switch group includes N back-end switches corresponding to the N batteries, one end of the N front-end switches is connected to one end of the bidirectional AC/DC module, and the i-th front-end switch is connected to one end of the bidirectional AC/DC module. The other end is connected with the positive end of the power supply of the i-th battery corresponding to itself, one end of the i-th rear end switch is connected with the power supply negative end of the i-th battery corresponding to itself, and the other ends of the N back-end switches After connection, connect to the other end of the bidirectional AC/DC module, 1≤i≤N, and i is an integer;

Controlling the switch circuit includes:

The front end switch group is controlled, and the rear end switch group is controlled.

Preferably, before acquiring the voltage across each of the battery power sources, the method further includes:

Controlling the first front-end switch and the Nth back-end switch to be closed, and controlling the bidirectional AC/DC module to be in a rectification mode, so that the N batteries enter the charging process;

Or, the first front-end switch and the Nth back-end switch are controlled to be closed, and the bidirectional AC/DC module is controlled to be in the inverter mode, so that the N batteries enter the discharging process.

In order to solve the above technical problems, the present invention also provides a charge and discharge control device, comprising:

memory for storing computer programs;

The processor is configured to implement the steps of the above-mentioned charging and discharging control method when executing the computer program.

In order to solve the above technical problems, the present invention also provides an energy storage system, which includes a switch circuit, N batteries connected in series, and the above-mentioned charge-discharge control device.

Preferably, the energy storage system further includes a bidirectional AC/DC module, the switch circuit includes a front-end switch group and a rear-end switch group, and the front-end switch group includes N front-end switches corresponding to the N batteries. , the back-end switch group includes N back-end switches corresponding to the N batteries, one end of the N front-end switches is connected to one end of the bidirectional AC/DC module, and the i-th front-end switch is connected to one end of the bidirectional AC/DC module. The other end is connected with the positive end of the power supply of the i-th battery corresponding to itself, one end of the i-th rear end switch is connected with the power supply negative end of the i-th battery corresponding to itself, and the other ends of the N back-end switches After connection, it is connected to the other end of the bidirectional AC/DC module, 1≤i≤N, and i is an integer.

Preferably, the number of the bidirectional AC/DC modules is multiple, and the multiple bidirectional AC/DCs are connected in parallel, and one end of the N front-end switches is connected to the multiple bidirectional AC/DC modules. The paralleled first common terminal is connected, and the other terminals of the N back-end switches are connected to the paralleled second common terminal of the plurality of bidirectional AC/DC modules.

The present application provides a charging and discharging control method. In the method, in the process of using N batteries to charge or discharge, the power supply voltage of each battery is obtained in real time, and when there is a battery whose power supply voltage reaches a preset threshold, the It is determined as an unbalanced battery, and the battery whose power supply has not reached the preset threshold is determined as a balanced battery, and then the switch circuit is controlled to stop the charge and discharge of the unbalanced battery, and control the balanced battery to continue to charge and discharge. process until the power supply voltage of N batteries reaches the preset threshold, which can make all batteries achieve better charging and discharging effect, ensure that N batteries can achieve balanced charging and discharging, which is beneficial to improve battery life and charging and discharging. stability.

The present application also provides a charge-discharge control device and an energy storage system, which have the same beneficial effects as the charge-discharge control method described above.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the prior art and the accompanying drawings required in the embodiments. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

1 is a schematic flowchart of a charging and discharging control method provided by the present invention;

2 is a structural block diagram 1 of an energy storage system provided by the present invention;

3 is a schematic block diagram 1 of the process of the energy storage system provided by the present invention;

FIG. 4 is a second schematic block diagram of the process of the energy storage system provided by the present invention;

FIG. 5 is a schematic diagram of a specific flow of the charging of the energy storage system provided by the present invention;

Fig. 6 is the specific flow chart of the energy storage system discharge provided by the present invention;

7 is a structural block diagram of a charge and discharge control device provided by the present invention;

FIG. 8 is a second structural block diagram of an energy storage system provided by the present invention.

Detailed ways

The core of the present invention is to provide a charging and discharging control method, device and energy storage system, which can make all batteries achieve the best charging and discharging effect and ensure that N batteries can achieve balanced charging and discharging.

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Considering that during the use of the battery, with the prolongation of the use time, the capacity of the battery will change, which will cause the battery capacity in the battery pack to be unbalanced. For example, if N batteries are a battery pack, and N batteries are connected in series, if there is an imbalance in the battery pack, it will occur. When charging N batteries, the power supply voltage of the N batteries first reaches the maximum charging threshold. At this time, it will stop charging the battery pack, but there are still batteries in the battery pack whose power supply voltage has not reached the maximum charging threshold. Therefore, during the charging process, there will be an unbalanced phenomenon. Similarly, during the discharge process, as long as there are batteries in the battery pack whose power supply voltage is less than the minimum discharge threshold, the battery pack will be controlled to stop discharging, that is, all the batteries in the battery pack will be controlled to stop discharging, and imbalance will also occur. The phenomenon. It can be seen that when the capacity of the batteries in the battery pack is unbalanced, it may happen that the batteries in the battery pack are not fully charged or discharged, and the available energy in the battery pack is less.

Please refer to FIG. 1. FIG. 1 is a schematic flowchart of a charging and discharging control method provided by the present invention. The method is applied to a processor in an energy storage system. The energy storage system includes a switch circuit and N batteries connected in series, where N is greater than or equal to Integer of 1; methods include:

S11: During the charging and discharging process, obtain the power supply voltage of each battery in real time;

Specifically, considering that the battery is in the process of charging and discharging, it is mainly determined by the power supply voltage of the battery whether the battery has been fully discharged or whether the battery has been fully charged. Therefore, in the present application, during the charging and discharging process, the power supply voltage of the battery is acquired in real time, so as to subsequently determine whether the battery has completed charging and discharging based on the power supply voltage of the battery.

It should be noted that the specific implementation of obtaining the power supply voltage of the battery in the present application may be, but not limited to, obtaining the power supply voltage of each battery by obtaining BMS (BATTERY MANAGEMENT SYSTEM, battery management system) information of the battery pack. At this time, the processor communicates with the BMS of the battery pack through the serial port.

It should also be noted that in this application, in order to further avoid the unbalanced phenomenon of the battery pack, the N batteries are batteries of the same specification, which may be lithium batteries or lithium iron phosphate batteries or ternary lithium batteries. no longer limited.

S12: Determine whether there is a battery whose power supply voltage reaches a preset threshold;

Specifically, during the charging and discharging process of the battery, the way to indicate that the battery has completed charging or discharging is: judging whether the power supply voltage of the battery reaches the preset threshold value for charging or the preset threshold value for discharging, and if so, it is determined that the battery has completed charging or The discharge is completed, otherwise, it is determined that the battery has not completed the charging process or the discharging process.

As a preferred embodiment, determining whether there is a battery whose power supply voltage reaches a preset threshold includes:

During the charging process, determine whether there is a battery whose power supply voltage reaches a first preset threshold;

And, during the discharging process, it is determined whether there is a battery whose power supply voltage reaches a second preset threshold, where the first preset threshold is greater than the second preset threshold.

Specifically, during the charging process, a specific implementation manner of determining whether there is a battery whose power supply voltage reaches a preset threshold is: determining whether there is a battery whose power supply voltage reaches a first preset threshold, where the first preset threshold may be the battery at a standard value. The voltage corresponding to a full charge. Similarly, during the discharging process, the specific implementation method of determining whether there is a battery whose power supply voltage reaches a preset threshold is: determining whether there is a battery whose power supply voltage reaches a second preset threshold, wherein the second preset threshold can be the battery in the standard value. Under the circumstances, the voltage corresponding to the discharge is completed. That is, when the power supply voltage reaches the first preset threshold, it is determined that the charging is completed, and when the power supply voltage reaches the second preset threshold, it is determined that the discharging is completed.

S13: If there is, use the battery whose power supply voltage reaches the preset threshold as an unbalanced battery, and use the battery whose power supply voltage does not reach the preset threshold as a balanced battery;

S14: Control the switch circuit so that the unbalanced battery stops charging and discharging, and the balanced battery continues to charge and discharge until the power supply voltages of the N batteries reach a preset threshold.

Since N batteries are connected in series, when there are batteries that reach the preset threshold, in the prior art, N batteries are controlled to stop charging and discharging at the same time. At this time, the batteries whose power supply voltage does not reach the preset threshold are fully charged or charged. Not fully discharged, so that the stored and available power of the N batteries is low.

Therefore, in this application, in order to enable N series-connected batteries to be fully charged or fully discharged during the charging and discharging process, a battery whose power supply voltage reaches a preset threshold is determined to be an unbalanced battery (here refers to the battery that is earlier in the charging and discharging process). reach the preset threshold), otherwise, it is determined as a balanced battery; then, when an unbalanced battery occurs in the N batteries (that is, the battery has been fully charged or fully discharged), the unbalanced battery is removed from the charge-discharge loop. Separated to avoid affecting other balanced batteries to continue charging and discharging.

As a preferred embodiment, the switching circuit is controlled to stop the charging and discharging of the unbalanced battery and continue to charge the balanced battery until the power supply voltages of the N batteries reach the preset threshold, including:

grouping the balanced batteries according to preset conditions;

By controlling the switch circuit, each balanced battery group is sequentially charged and discharged until the power supply voltages of the N batteries reach the preset threshold.

This embodiment aims to provide a specific charging method for the remaining balanced batteries after unbalanced batteries appear in the N batteries. Specifically, all the balanced batteries can be grouped, and then the switch circuit can be controlled to charge and discharge each balanced battery group in turn, so as to fully charge or completely discharge all the balanced batteries.

The preset condition may be: the balanced battery located on one side of the power supply of the unbalanced battery is a set of balanced battery packs, and the balanced battery located on the other side of the power supply of the unbalanced battery is another set of balanced battery packs. Or the preset condition can be described as: taking the unbalanced battery as the split point, grouping the balanced battery, taking each continuous series-connected balanced battery as a set of balanced battery packs, and then controlling one of the balanced battery packs to charge and discharge each time , until the power supply voltage of all batteries reaches the preset threshold. Further, the preset condition may also equalize the number of batteries. In this case, the equalized batteries are grouped according to the number of equalized batteries, for example, two equalized batteries are charged at a time, etc., which is not limited here.

It should be noted that, if there is only one balanced battery between two unbalanced batteries, although the battery is not connected in series, this balanced battery is still used as a group.

In addition, a specific implementation manner of sequentially charging and discharging each balanced battery group is as follows: sequentially performing charging and discharging on each balanced battery group according to a time sequence.

Through the grouping method in this embodiment, even if there is an unbalanced battery, other balanced batteries can still be controlled to continue charging and discharging, and the method of controlling the charging and discharging of each battery in sequence is not adopted, which can reduce the time consuming of charging and discharging. Improve efficiency.

As a preferred embodiment, after charging and discharging each balanced battery pack in sequence by controlling the switch circuit, the method further includes:

Obtain the power supply voltage of the currently charged and discharged battery, and re-enter the step of determining whether there is a battery whose power supply voltage reaches a preset threshold.

In addition, after each grouping of balanced batteries, further, the power supply voltage of the batteries that are currently being charged and discharged normally will be obtained to determine whether unbalanced batteries will still occur. If so, continue to repeat the above to remove unbalanced batteries. steps until all batteries reach the preset threshold.

The steps in this embodiment are actually a process of continuously grouping N batteries until each battery is fully charged or completely discharged.

As a preferred embodiment, the energy storage system further includes a bidirectional AC/DC (Alternating Current-direct current, alternating current-direct current) module, the switch circuit includes a front-end switch group and a back-end switch group, and the front-end switch group includes and N batteries One-to-one corresponding N front-end switches, the back-end switch group includes N back-end switches corresponding to N batteries, one end of the N front-end switches is connected to one end of the bidirectional AC/DC module, and the i-th front-end switch is connected to one end of the bidirectional AC/DC module. The other end is connected to the positive end of the power supply of the i-th battery corresponding to itself, one end of the i-th rear end switch is connected to the negative end of the power supply of the i-th battery corresponding to itself, and the other ends of the N back-end switches are connected to the bidirectional The other end of the AC/DC module is connected, N≥i≥1, and i is an integer;

Controls switching circuits, including:

Control the front-end switch group and control the rear-end switch group.

Specifically, this embodiment aims to provide a specific implementation of a switch circuit. Please refer to FIG. 2 , which is a first structural block diagram of an energy storage system provided by the present invention. Wherein, in this embodiment, a bidirectional AC/DC module is used as the charging and discharging interface. Compared with setting a DC/DC (direct current-direct current) module for each battery, the DC/DC module is controlled by controlling the DC/DC module. The cost of using a bidirectional AC/DC module is lower when the power supply voltage of each battery is the same during charging and discharging.

It should be noted that the total power of the number of batteries connected to the back end of the bidirectional AC/DC module should not be greater than the power output by the bidirectional AC/DC module. Take a 20KW bidirectional AC/DC module and a 100V/40A battery as an example, at this time, N≤5 is appropriate.

At this time, correspondingly, when an unbalanced battery occurs, the front-end switch group and the back-end switch group in the switch circuit are controlled until the power supply voltages of the N batteries reach the preset threshold.

As a preferred embodiment, before acquiring the voltages at both ends of each battery power source, the method further includes:

Controlling the first front-end switch and the Nth back-end switch to close, and controlling the bidirectional AC/DC module to be in the rectification mode, so that the N batteries enter the charging process;

Or, control the first front-end switch to be closed and the Nth back-end switch to be closed, and control the bidirectional AC/DC module to be in the inverter mode, so that the N batteries enter the discharging process.

Please refer to FIG. 3 and FIG. 4 , FIG. 3 is a schematic block diagram 1 of the process of the energy storage system provided by the present invention; FIG. 4 is a schematic block diagram 2 of the process of the energy storage system provided by the present invention.

Further, on the basis of the above-mentioned embodiment, please refer to FIG. 5 and FIG. 6 , FIG. 5 is a schematic diagram of a specific flow of charging an energy storage system provided by the present invention, and FIG. 6 is a schematic schematic diagram of a specific flow of discharging an energy storage system provided by the present invention. .

When the switch circuit is the specific implementation in FIG. 2, at this time, the battery charging process of the energy storage system is described as:

Step 1, first, control the bidirectional AC/DC module to be in rectification mode, so as to rectify the alternating current of the power grid into direct current to charge the battery;

Step 2, close S1 and Qn to charge all the batteries (ie N batteries) in the battery pack;

Step 3: Obtain the BMS information of the battery pack in real time and determine that when the power supply voltage of any battery reaches (that is, is greater than or equal to) the first preset threshold, determine that the battery is an unbalanced battery and interrupt the charging process of the battery (such as As shown in Figure 3, the second battery is an unbalanced battery);

Step 4, as shown in Figure 3, at this time, the second battery is used as the dividing point, the first battery is used as a set of balanced battery packs, and the third battery to the Nth battery is used as another set of balanced battery packs. First close S1 and Q1 to charge the first battery until it reaches the maximum threshold of the power supply voltage of the first battery (when the specifications of the batteries in the battery pack are the same, the maximum threshold is the first preset threshold); then As shown in Figure 4, at this time, close S3 and Qn to charge another set of balanced battery packs (ie, the third battery, the fourth battery...the Nth battery), and then if there are other batteries in the battery pack When the power supply voltage reaches the first preset threshold, return to step 3 to continue to remove unbalanced batteries, otherwise continue to charge.

The battery discharge process of this energy storage system is described as:

Step 1: First, control the bidirectional AC/DC module to be in the inverter mode, so as to invert the DC power output by the battery and output it to the power grid;

Step 2, first close S1 and Qn to discharge all the batteries in the elevator battery pack;

Step 3: Obtain the BMS information of the battery pack in real time and determine that when the power supply voltage of any battery reaches (that is, less than or equal to) the minimum threshold (that is, the second preset threshold) of the battery, determine that the battery is an unbalanced battery. , and interrupt the entire discharge process (as shown in Figure 3, the second battery is an unbalanced battery);

Step 4, as shown in Figure 3, at this time, close S1 and Q1 to discharge the first battery until it reduces to the minimum battery threshold of the first battery, and then as shown in Figure 4, at this time, close S3 and Qn to discharge the first battery. The three batteries, the fourth battery... The Nth battery is discharged, and then if the power supply voltage of other batteries in the battery is reduced to the second preset threshold, then return to step 3 to continue to remove unbalanced batteries, otherwise Continue to discharge until the supply voltage of all cells in the battery pack reaches the second preset threshold.

Please refer to FIG. 7. FIG. 7 is a structural block diagram of a charging and discharging control device provided by the present invention, and the device includes:

memory 71 for storing computer programs;

The processor 72 is configured to implement the steps of the above-mentioned charging and discharging control method when executing the computer program.

In order to solve the above technical problems, the present application also provides a charge and discharge control device. For the introduction of the charge and discharge control device, please refer to the above-mentioned embodiments, which will not be repeated in the present application.

An energy storage system includes N batteries connected in series, a switch circuit, and the above-mentioned charge-discharge control device.

As a preferred embodiment, the energy storage system further includes a bidirectional AC/DC module, the switch circuit includes a front-end switch group and a back-end switch group, the front-end switch group includes N front-end switches corresponding to the N batteries, and the back-end switch group includes N front-end switches corresponding to the N batteries. The switch group includes N back-end switches corresponding to N batteries, one end of the N front-end switches is connected to one end of the bidirectional AC/DC module, and the other end of the i-th front-end switch is connected to the i-th battery corresponding to itself. The positive end of the power supply is connected to the ith back-end switch, one end of the i-th back-end switch is connected to the negative end of the power supply of the i-th battery corresponding to itself, and the other end of the N back-end switches is connected to the other end of the bidirectional AC/DC module, N≥ i≥1, and i is an integer.

Please refer to FIG. 8 , which is a second structural block diagram of an energy storage system provided by the present invention.

As a preferred embodiment, the number of bidirectional AC/DC modules is multiple, and the multiple bidirectional AC/DC modules are connected in parallel, and one end of the N front-end switches is connected in parallel with the multiple bidirectional AC/DC modules. The first common terminal of the N back-end switches is connected, and the other terminals of the N back-end switches are connected to the second common terminal after being connected in parallel with a plurality of bidirectional AC/DC modules.

Due to the limitation of the power and DC output voltage of the current bidirectional AC/DC module (taking a 20KW bidirectional AC/DC module and a battery of 100V/40A as an example, N≤5 is appropriate), a large-scale energy storage system can include multiple parallel connections. The bidirectional AC/DC module and more battery packs are controlled by the charging and discharging bidirectional AC/DC module to determine the charging and discharging operation of all the battery packs of the ladder according to the BMS information of each battery pack. For other introductions to the energy storage system, please refer to the above-mentioned embodiments, which will not be repeated in this application.

As a preferred embodiment, the energy storage system further includes a plurality of control switches 81 corresponding to the plurality of bidirectional AC/DC modules one-to-one, and one end of each control switch 81 is connected to one end of the bidirectional AC/DC module corresponding to itself. connected, the other end of each control switch 81 is connected as a second common end, and the other ends of a plurality of bidirectional AC/DC modules are connected to form a first common end.

Specifically, when there are multiple bidirectional AC/DC modules and they are connected in parallel, it is suitable for a larger energy storage system. Considering that the capacity of the energy storage system may change with demand, for example, when the specifications of N batteries change and the total capacity of the N batteries changes, the number of bidirectional AC/DC modules to be used may also be required. make adjustments.

Therefore, in order to facilitate the use of the energy storage system, in this embodiment, a control switch 81 is connected in series at each bidirectional AC/DC module, as shown in FIG. 8 , at this time, when the control switch 81 is closed, the corresponding bidirectional AC/DC The module is used, otherwise, it is not used. By controlling the switch 81, the total capacity of the multiple bidirectional AC/DC modules can be adjusted, so that it can be applied to more energy storage systems with different capacities.

It should be noted that in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities or operations There is no such actual relationship or order between them. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

Professionals may further realize that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two, in order to clearly illustrate the possibilities of hardware and software. Interchangeability, the above description has generally described the components and steps of each example in terms of functionality. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each particular application, but such implementations should not be considered beyond the scope of the present invention.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A charge-discharge control method, characterized in that it is applied to a processor in an energy storage system, the energy storage system comprising a switch circuit and N batteries connected in series, and N is an integer greater than 1; the method comprises: During the charging and discharging process, obtain the power supply voltage of each battery in real time; determine whether there is a battery with a supply voltage that reaches a preset threshold; If there is, the battery whose power supply voltage reaches the preset threshold is determined as an unbalanced battery, and the battery whose power supply voltage does not reach the preset threshold is determined as a balanced battery; The switch circuit is controlled to stop charging and discharging of the unbalanced battery, and continue charging and discharging of the balanced battery until the power supply voltages of the N batteries reach the preset threshold. 2 . The charging and discharging control method according to claim 1 , wherein the switching circuit is controlled to stop charging and discharging of the unbalanced battery, and continue charging and discharging of the balanced battery until N all The power supply voltage of the battery reaches the preset threshold, including: grouping the balanced batteries according to preset conditions; By controlling the switch circuit, each balanced battery group is sequentially charged and discharged until the power supply voltages of the N batteries reach the preset threshold. 3. The charge-discharge control method according to claim 2, characterized in that, after sequentially charging and discharging each balanced battery pack by controlling the switch circuit, the method further comprises: Obtain the power supply voltage of the currently charged and discharged battery, and re-enter the step of determining whether there is a battery whose power supply voltage reaches a preset threshold. 4. The charge-discharge control method according to claim 1, wherein determining whether there is a battery whose power supply voltage reaches a preset threshold comprises: During the charging process, determine whether there is a battery whose power supply voltage reaches a first preset threshold; And, during the discharging process, it is determined whether there is a battery whose power supply voltage reaches a second preset threshold, and the first preset threshold is greater than the second preset threshold. 5. The charge-discharge control method according to any one of claims 1-4, wherein the energy storage system further comprises a bidirectional AC/DC module, and the switch circuit comprises a front-end switch group and a back-end switch group, The front-end switch group includes N front-end switches corresponding to the N batteries, the rear-end switch group includes N back-end switches corresponding to the N batteries, and the N front-end switches One end is connected to one end of the bidirectional AC/DC module, the other end of the i-th front-end switch is connected to the positive end of the power supply of the i-th battery corresponding to itself, and one end of the i-th rear-end switch is connected to the power supply corresponding to itself. The negative end of the power supply of the i-th battery is connected, and the other ends of the N back-end switches are connected to the other end of the bidirectional AC/DC module, 1≤i≤N, and i is an integer; Controlling the switch circuit includes: The front end switch group is controlled, and the rear end switch group is controlled. 6. The charge-discharge control method according to claim 5, wherein before acquiring the power supply voltage of each of the batteries, the method further comprises: controlling the first front-end switch and the Nth back-end switch to be closed, and controlling the bidirectional AC/DC module to be in a rectification mode, so that the N batteries enter the charging process; Or, control the first front-end switch to be closed and the Nth back-end switch to be closed, and control the bidirectional AC/DC module to be in an inverter mode, so that the N batteries enter the discharging process. 7. A charge and discharge control device, comprising: memory for storing computer programs; The processor is configured to implement the steps of the charging and discharging control method according to any one of claims 1-6 when executing the computer program. 8 . An energy storage system, comprising a switch circuit, N batteries connected in series, and the charge-discharge control device according to claim 7 . 9. The energy storage system according to claim 8, wherein the energy storage system further comprises a bidirectional AC/DC module, the switch circuit comprises a front-end switch group and a back-end switch group, and the front-end switch group comprises N front-end switches corresponding to the N batteries, the back-end switch group includes N back-end switches corresponding to the N batteries, and one end of the N front-end switches is connected to the battery. One end of the two-way AC/DC module is connected, the other end of the i-th front-end switch is connected to the positive end of the power supply of the i-th battery corresponding to itself, and one end of the i-th rear end switch is connected to the power supply of the i-th battery corresponding to itself. The negative terminal is connected, and the other terminals of the N back-end switches are connected to the other terminal of the bidirectional AC/DC module, 1≤i≤N, and i is an integer. 10 . The energy storage system according to claim 9 , wherein the number of the bidirectional AC/DC modules is multiple, and the multiple bidirectional AC/DC modules are connected in parallel, and N front-ends are connected. 11 . One end of the switch is connected to the first common end of the plurality of bidirectional AC/DC modules in parallel, and the other end of the N back-end switches is connected to the first common end of the plurality of bidirectional AC/DC modules in parallel. Two common terminal connections.

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