WO2024050964A1

WO2024050964A1 - Parallel charging control method for multiple battery packs, and energy storage device and system

Info

Publication number: WO2024050964A1
Application number: PCT/CN2022/132155
Authority: WO
Inventors: 幸云辉; 于扬鑫
Original assignee: 深圳市正浩创新科技股份有限公司
Priority date: 2022-09-05
Filing date: 2022-11-16
Publication date: 2024-03-14
Also published as: CN115995863A

Abstract

A parallel charging control method for multiple battery packs, comprising: respectively calculating charging current differences between required charging currents of battery packs and actual charging currents of the battery packs, and determining the battery pack having the smallest charging current difference as a reference battery pack; according to the required charging current of the reference battery pack and the actual charging currents of the battery packs, calculating target charging currents of the battery packs during a parallel charging steady state; determining a target parallel charging current according to the target charging currents of the battery packs; and generating a target charging instruction according to the target parallel charging current, and sending the target charging instruction to a power supply.

Description

Parallel charging control method, energy storage device and system for multiple battery packs

Cross-references to related applications

This application requests the priority of the Chinese patent application submitted to the China Patent Office on September 5, 2022, with the application number 202211099154.1 and the invention title "Parallel charging control method, energy storage equipment, system and medium for multiple battery packs", The entire contents of which are incorporated herein by reference.

Technical field

This application relates to the technical field of charging control, and specifically relates to a parallel charging control method, energy storage equipment, system and medium for multiple battery packs.

Background technique

The statements herein merely provide background information relevant to the present application and do not necessarily constitute exemplary techniques.

With the increasing development of science and technology, electronic products have become indispensable daily necessities for people. In order to conveniently charge electronic products, various types of mobile power supplies and other energy storage products were born, and the most important energy storage part of energy storage equipment is the battery pack.

If the battery pack is in an overcurrent charging state for a long time, its life will be easily affected. Therefore, the charging control of the battery pack is crucial to extending the life of the battery pack. When multiple battery packs are charged in parallel, the charging control is more complex and over-current charging is more likely to occur. Therefore, how to achieve charging control when multiple battery packs are charged in parallel is particularly important to extend the service life of energy storage equipment.

Contents of the invention

Embodiments of the present application provide a parallel charging control method and device for multiple battery packs, an energy storage device, an energy storage system, and a computer-readable storage medium.

According to one aspect of the embodiment of the present application, a parallel charging control method for multiple battery packs is provided. The method is applied to a controller, and the controller establishes a communication connection with each battery pack. The method includes: calculating respectively The charging current difference between the required charging current of the battery pack and the actual charging current of each battery pack, the battery pack with the smallest charging current difference is determined as the reference battery pack; according to the required charging current of the reference battery pack and The actual charging current value of each battery pack is used to calculate the target charging current of each battery pack in the steady state of parallel charging; wherein, when the battery pack is in the steady state of parallel charging, the charging current of the reference battery pack The difference is less than the preset current threshold; determine the target parallel charging current according to the target charging current of each battery pack; generate a target charging instruction according to the target parallel charging current, and send the target charging instruction to the power supply. The charging instruction is used to instruct the power supply to output the target parallel charging current to charge the multi-battery pack.

According to another aspect of the embodiment of the present application, a parallel charging control device for multiple battery packs is provided, which is applied to a controller, and the controller establishes a communication connection with each battery pack. The device includes: determining with reference to the battery pack A module configured to calculate the charging current difference between the required charging current of each battery pack and the actual charging current of each battery pack, and determine the battery pack with the smallest charging current difference as the reference battery pack; target charging current calculation A module configured to calculate the target charging current of each battery pack in the steady state of parallel charging based on the demand charging current of the reference battery pack and the actual charging current value of each battery pack; wherein, the battery pack is in the When parallel charging is in steady state, the charging current difference of the reference battery pack is less than the preset current threshold; the target parallel charging current determination module is configured to determine the target parallel charging current based on the target charging current of each of the battery packs; A target charging instruction sending module configured to generate a target charging instruction according to the target parallel charging current, and send a target charging instruction to the power supply, where the target charging instruction is used to instruct the power supply to output the target parallel charging current. Charge the multi-battery pack.

According to another aspect of the embodiment of the present application, an energy storage device is provided, the parallel port is used to connect to other energy storage devices or independent battery packs, the controller establishes connections with each battery pack, and the Computer-readable instructions are stored in the memory. When the computer-readable instructions are executed by the controller, the parallel charging control method of multiple battery packs as described above is implemented.

According to another aspect of the embodiment of the present application, an energy storage system is provided, including at least two energy storage devices connected through a parallel port, and at least one of the energy storage devices is the energy storage device as described above.

According to another aspect of the embodiment of the present application, a computer-readable storage medium is provided, with computer-readable instructions stored thereon. When the computer-readable instructions are executed by a computer, the computer is caused to execute the multi-battery process as described above. Package parallel charging control method.

The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below. Other features, objects and advantages of the application will become apparent from the description, drawings and claims.

It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present application.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments or exemplary technologies of the present application, the drawings required for description of the embodiments or exemplary technologies will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, drawings of other embodiments can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic diagram of the charging process of a single battery pack under ideal conditions.

Figure 2 is a schematic diagram of the charging process of a single battery pack when the rising speed of the power supply output current is much lower than the accumulating speed of the charging current requested by the proportional control algorithm.

Figure 3 is a schematic structural diagram of parallel charging of multiple battery packs according to an exemplary embodiment of the present application.

FIG. 4 is a flowchart of a parallel charging control method for multiple battery packs according to an exemplary embodiment of the present application.

FIG. 5 is a flowchart of step S420 in the embodiment shown in FIG. 4 in one embodiment.

FIG. 6 is a flowchart of step S430 in the embodiment shown in FIG. 4 in one embodiment.

FIG. 7 is a flowchart of step S430 in the embodiment shown in FIG. 4 in another embodiment.

FIG. 8 is a block diagram of another exemplary parallel charging control device for a multi-battery pack of the present application.

Figure 9 is a schematic structural diagram of another exemplary energy storage device of the present application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application. First introduce the following definitions:

Demand charging current of the battery pack (need_chg_amp): The optimal charging current of the battery pack is determined by the characteristics of the battery pack and the battery pack hardware circuit.

The actual charging current of the battery pack (real_chg_amp): The real charging current of the battery pack.

The charging current difference of the battery pack (error_value): It is the difference between the required charging current of the battery pack and the actual charging current, that is, error_value=need_chg_amp-real_chg_amp.

Charging current requested from the power supply (send_chg_amp): The charging current actually requested from the power supply in the charging request. The power supply outputs a corresponding current to the battery pack according to the requested charging current. It can be understood that when multiple battery packs are charged in parallel, the charging current requested from the power supply is the target parallel charging current, that is, the sum of the required charging currents of each battery pack.

At present, the charging process of a single battery pack is usually carried out through deviation control algorithms, such as proportional control algorithm (also called P correction), differential control algorithm (also called D control), proportional integral differential control algorithm (also called PID correction) Charging control is explained in this application by taking the proportional control algorithm as an example. The purpose of using a proportional control algorithm for charging control is to control the actual charging current of the battery pack around the required charging current, and its deviation can usually be controlled within a preset threshold, for example, around 1A. In the process of using the proportional control algorithm for battery pack charging control, the charging current requested from the power supply is calculated by the following formula:

send_chg_amp _k =send_chg_amp _k-1 +kp*error_value _k

Among them, send_chg_amp _k represents the charging current requested from the power supply this time, send_chg_amp _k-1 is the charging current requested from the power supply last time, the request period can be set according to actual needs, and error_value _k represents the current charging current difference. kp represents the proportional coefficient, which is a value determined by the charging characteristics of the battery pack and the circuit characteristics of the charging circuit, and can be obtained through testing.

When real_chg_amp<need_chg_amp, error_value is positive, send_chg_amp will continue to accumulate, and real_chg_amp gradually becomes larger until it is close to need_chg_amp. On the contrary, when real_chg_amp>need_chg_amp, error_value is negative, send_chg_amp gradually decreases, the parallel charging current output by the power supply also decreases, and real_chg_amp decreases accordingly until it is close to need_chg_amp. By continuously cycling the above charging control process, real_chg_amp is finally stabilized around need_chg_amp.

As shown in Figure 1, under ideal conditions real_chg_amp and send_chg_amp will eventually stabilize near need_chg_amp.

However, if real_chg_amp rises slowly or the current output capability of the external power supply is limited, the rising speed of the power supply output current will be much lower than the rising speed of the charging current requested by the battery pack, which will cause real_chg_amp to stabilize at When need_chg_amp is near, send_chg_amp is much larger than real_chg_amp, as shown in Figure 2.

For example, assume the battery pack need_chg_amp is 100A. At a certain moment, due to the limitation of the power supply output capacity, real_chg_amp can only reach about 100A when send_chg_amp is about 120A. Although real_chg_amp can be stable around need_chg_amp at this time, there are hidden dangers: that is, the send_chg_amp currently sent to the power supply is much larger than real_chg_amp. However, at this moment, the power supply can only support the output of a maximum charging current of 100A. However, if the output power of the power supply increases, , for example, the power supply can support the output of a charging current of 120A (for example, in a photovoltaic charging scenario, the power supply determines the output current based on the intensity of sunlight), then the power supply will provide a charging current of 120A to the battery pack, that is, the battery The real_chg_amp of the pack will reach about 120A, far exceeding the need_chg_amp of the battery pack. At this time, the overcurrent protection will be triggered and the charging MOS (Metal-Oxide-Semiconductor Field-Effect Transistor, Metal Oxide Semiconductor Field Effect Transistor) on the battery pack will be turned off. After the overcurrent protection time has passed, the above charging process will be repeated, which will cause the battery pack to have repeated charging overcurrent problems, which may easily lead to damage to the battery pack.

If need_chg_amp is used as send_chg_amp to request charging current from the power supply, there will be no overcurrent problem. However, the charging current need_chg_amp required for charging a single battery pack can be determined. However, in the scenario of parallel charging of multiple battery packs, when multiple battery packs are charged in parallel, the total required charging current of multiple battery packs must not only consider the single battery. In addition to the required charging current of the pack, the line loss voltage and internal resistance of each battery pack also need to be considered. The line loss voltage and internal resistance of each battery pack cannot be determined. For example, the internal resistance of the current pack during the charging process is The changing line loss voltage is determined by the change in the length of the line connecting the power supply to the battery pack, and the length of this line is also uncontrollable.

For example, see FIG. 3 , which is a schematic structural diagram of parallel charging of multiple battery packs according to an exemplary embodiment of the present application. It should be noted that Figure 3 only shows the parallel charging of three battery packs. In actual application scenarios, the number of battery packs for parallel charging can be set according to actual needs. This is not the case here. Make restrictions. In addition, it should be noted that the multi-battery packs mentioned in this application can be multiple battery packs installed in the same energy storage device, or they can also be multiple battery packs distributed in multiple energy storage devices. It can be understood that when multiple battery packs are charged in parallel, the charging current send_chg_amp requested from the power supply is the target parallel charging current.

As shown in Figure 3, when battery pack A, battery pack B, and battery pack C are charged in parallel, the charging current I assigned to each battery pack is calculated by the following formula:

I＝(charging voltage Uc-battery pack voltage Ub-line loss voltage U1)/battery pack internal resistance

The charging voltage Uc of each battery pack is the same, and there will be a deviation of several hundred millivolts between the battery pack voltages Ub of each battery pack. However, the line loss voltage U1 of each battery pack and the internal resistance of the battery pack cannot be calculated, so In the process of parallel charging of multiple battery packs, the charging current allocated to each battery pack cannot be calculated, so the total required charging current of multiple battery packs cannot be directly determined.

For example, the required charging current of battery packs A-C are all 50A. If the sum of the required charging currents of the three battery packs is directly used as the total required charging current of 150A, due to the different wire loss or internal resistance of each battery pack, each battery pack will have different charging current requirements. The obtained current ratio is not consistent with the ratio between the required charging current of each battery pack. For example, the following situation may occur: the actual charging current of battery pack A is 50A, the actual charging current of battery pack B is only 20A, and the actual charging current of battery pack C is only 30A, that is, the actual charging current allocated to each battery pack The current ratio is not 1:1:1, but 5:2:3. If a current of 150A is requested from the power supply at this time, the actual charging current allocated to battery pack A is 75A, which is far more than the required charging current of 50A for battery pack A, causing battery pack A to have an overcurrent protection problem.

And in actual application scenarios, there are no known parameters that can be used to calculate the current distribution ratio between battery packs in advance, so it is impossible to accurately determine the total charging current demand of multiple battery packs when multiple battery packs are charged in parallel. .

In order to solve the above problems existing in the parallel charging scenario of multiple battery packs, embodiments of the present application propose a parallel charging control scheme for multiple battery packs. The contents of these embodiments will be introduced in detail below.

Please refer to FIG. 4 , which is a flow chart of a parallel charging control method for multiple battery packs according to an exemplary embodiment of the present application. This method is applied to a controller in an energy storage device, and the controller establishes a communication connection with each battery pack. As shown in the figure, the method includes steps S410-S440.

Step S410: Calculate the charging current difference between the required charging current of each battery pack and the actual charging current of each battery pack, and determine the battery pack with the smallest charging current difference as the reference battery pack.

As mentioned before, the required charging current of a single battery pack is determined by the battery pack characteristics and the battery pack hardware circuit. Therefore, when the circuit design is completed, the required charging current of each battery pack has been determined. The actual charging current of a single battery pack can be obtained through sampling, for example, through a sampling resistor or current sensor. Therefore, the charging current difference of a single battery pack can be calculated during the parallel charging process of multiple battery packs.

For the battery pack with the smallest charging current difference, it will be the first to reach the charging steady state during parallel charging, that is, its actual charging current will be the first to be near the required charging current, so it is determined as the reference battery pack. It can be understood that for parallel charging of multiple battery packs, when any battery pack is in a stable charging state, the parallel charging of multiple battery packs can be considered to be in a stable parallel charging state.

Step S420: Calculate the target charging current of each battery pack in the steady state of parallel charging based on the demand charging current of the reference battery pack and the actual charging current value of each battery pack; wherein, when the battery pack is in the steady state of parallel charging, the reference battery The charging current difference of the package is less than the preset current threshold.

In the steady state of parallel charging, the actual charging current of the reference battery pack is close to the required charging current, that is, the difference in charging current of the reference battery pack is less than the preset current threshold. The preset current threshold is usually a smaller current value. , used to indicate that the deviation between the actual charging current and the required charging current of the reference battery pack is very small in the parallel charging steady state.

Considering that during the parallel charging process, the actual charging current of each battery pack is proportional, and in the steady state of parallel charging, the target charging current of the reference battery pack is close to its required charging current, so according to the reference The required charging current of the battery pack and the actual charging current value of each battery pack can be used to calculate the target charging current of each battery pack in the steady state of parallel charging.

It should be understood that here, the target charging current of each battery pack refers to the charging current output by the power supply and can be allocated to each battery pack, excluding the part lost due to line loss or battery internal resistance.

Step S430: Determine the target parallel charging current according to the target charging current of each battery pack.

As mentioned before, in the steady state of parallel charging, the actual charging current of the reference battery pack reaches the required charging current first. At this time, the actual charging current of other battery packs except the reference battery pack is less than or equal to the required charging current. Therefore, as long as the actual charging current of the reference battery pack is controlled to the required charging current, it is ensured that the actual charging current allocated to each battery pack will not exceed the required charging current, so there will be no problem of battery pack overcurrent. This is the moment when the charging current is the most stable, safest and most reasonable.

Since the target charging current of each battery pack in the steady state of parallel charging has been determined in step S420 based on the demand charging current of the reference battery pack and the actual charging current value of each battery pack, that is, the output of the power supply and can be determined. The charging current allocated to each battery pack can further determine the target parallel charging current requested from the power supply.

It should be understood that the target parallel charging current can be determined directly based on the sum of the target charging currents of each battery pack, or whether to use the target charging current can be determined based on different charging states. For example, the candidate charging current can be calculated according to the above-mentioned deviation adjustment algorithm, the target charging current and the candidate charging current can be compared, and then a suitable current can be selected as the final target parallel charging current.

Step S440, generate a target charging instruction according to the target parallel charging current, and send the target charging instruction to the power supply. The target charging instruction is used to instruct the power supply to output the target parallel charging current to charge the multi-battery pack.

The target charging command carries the target parallel charging current. After receiving the target charging command, the power supply will charge the multi-battery pack according to the target parallel charging current requested by the multi-battery pack.

As can be seen from the above, this embodiment refers to the required charging current of the battery pack and the actual charging current of each battery pack to calculate the target charging current of each battery pack in the steady state of parallel charging, so as to further determine the target requested from the power supply. Parallel charging current. Since the reference battery pack is the battery with the smallest charging current difference, during the parallel charging process, the actual charging current of the reference battery pack is the first to reach the actual demand charging current and is in the parallel charging steady state. This makes the When the target parallel charging current calculated by this application requests charging from the power supply, the target charging current of each battery pack will not exceed the required charging current of each battery pack. On the premise of ensuring that the charging current is large enough, overcurrent can be avoided. problem occurs, reducing damage due to over-current problems during the charging process of the battery pack, thus extending the service life of the corresponding energy storage equipment.

It should be understood that the parallel charging process of multiple battery packs is also a dynamic process. For example, when parallel charging is first entered, the controller can generate a charging instruction based on the preset initial parallel charging current to request the power supply to output charging current. , in the subsequent charging process, the target parallel charging current is dynamically calculated according to the method provided in this embodiment to request charging from the power supply, until charging is stopped after the charging is completed.

In addition, it should be noted that the controller can receive the heartbeat information sent by each battery pack and determine the number of connected battery packs based on the received heartbeat information. After determining that the number is greater than 1, that is, it is determined that the current number is more than 1. After the parallel charging scenario of the battery pack is completed, the parallel charging control process disclosed in the method provided in this embodiment is executed.

As an exemplary implementation, as shown in Figure 5, in step S420, based on the demand charging current of the reference battery pack and the actual charging current value of each battery pack, the target charging current of each battery pack in the parallel charging steady state is calculated. The process includes the following steps S421-S423.

Step S421: Use the required charging current of the reference battery pack as the target charging current of the reference battery pack in the steady state of parallel charging.

As mentioned before, in the steady state of parallel charging, the actual charging current of the reference battery pack reaches the required charging current first, and the actual charging current of the reference battery pack is close to the required charging current. Therefore, the required charging current of the reference battery pack will be used. As the parallel charging steady state, refer to the target charging current of the battery pack.

Step S422: Calculate the proportional relationship between the actual charging current of the reference battery pack and the actual charging current of the target battery pack. The target battery pack is any battery pack in the multi-battery pack except the reference battery pack.

In the process of parallel charging of multiple battery packs, the ratio between the actual charging current of each battery pack is constant, so the proportional relationship between the actual charging current of the reference battery pack and the actual charging current of the target battery pack can be calculated.

For example, in the scenario shown in Figure 3, if the actual charging current of battery pack A is expressed as I _A , the actual charging current of battery pack B is expressed as I _B , and the actual charging current of battery pack C is expressed as I _C , then Based on the characteristics of parallel circuits, the ratio between I _A , I _B , and I _C remains unchanged at any time. Therefore, as long as the proportional relationship is determined and the actual current of one battery pack is determined at any time, the actual charging current required by other battery packs can be determined, that is, the target charging current.

Step S423: Calculate the target charging current of each target battery pack in the steady state of parallel charging based on the proportional relationship and the target charging current of the reference battery pack.

Still taking the scenario shown in Figure 3 as an example, the charging current difference of battery pack A is expressed as error_I _A , the charging current difference of battery pack B is expressed as error_I _B , and the charging current difference of battery pack C is expressed as error_I _C , the charging current that needs to be increased to bring battery pack A to the parallel charging steady state is expressed as ΔI _A , the charging current that needs to be increased to bring battery pack B to the parallel charging steady state is expressed as ΔI B, and the charging current that battery pack C needs to reach the parallel charging steady state is expressed as ΔI _B. The additional charging current required for the steady state of mechanical charging is expressed as ΔI _C .

Assume that error_I _A is the smallest, so battery pack A is determined as the reference battery pack. As mentioned above, the actual charging current of the reference battery pack is infinitely close to the demand charging current when the parallel charging is in steady state. Therefore, the target charging current of the reference battery pack can be determined to be the demand charging current. According to the required charging current of battery pack A, it can be calculated that battery pack A also needs to charge a current of ΔI _A =error_I _A to enter the parallel charging steady state.

Known proportional relationship

and ΔI _A , where:

I _A ′ and I _B ′ represent the target charging current of battery packs A and B under parallel charging steady state, then we can get

The same can be obtained

Therefore, the target charging current of battery pack B in the steady state of parallel charging is I _B + ΔI _B , and the target charging current of battery pack C in the steady state of parallel charging is I _C + ΔI _C .

It can be seen from the above that this embodiment can calculate the target charging current of each target battery pack in the steady state of parallel charging based on the proportional relationship between the actual charging current of each battery pack and the target charging current of the reference battery pack, thereby facilitating Subsequently, the target parallel charging current used to request the power supply is determined based on the target charging current of each battery pack.

As an exemplary implementation, as shown in Figure 6, the process of determining the target parallel charging current according to the target charging current of each battery pack in step S430 includes the following steps S431-S434:

Step S431: Determine the first candidate charging current according to the target charging current of each battery pack.

In this embodiment, the first candidate charging current is the sum of the target charging currents of each battery pack obtained in step S420.

Step S432: Determine the second candidate charging current according to the historical parallel charging current and the proportional control algorithm. The historical parallel charging current is the target parallel charging current determined last time.

As mentioned above, in the process of using the proportional control algorithm to control the battery pack charging, the charging current requested from the power supply is determined based on the charging current requested from the power supply last time. In this embodiment, the second candidate charging current is determined according to the historical parallel charging current and the proportional control algorithm. It can be understood that the second candidate charging current is the charging current determined by using the proportional control algorithm that can be requested from the power supply.

Step S433: If the first candidate charging current is smaller than the second candidate charging current, determine the first candidate charging current as the target parallel charging current.

If the first candidate charging current is smaller than the second candidate charging current, it means that the charging current that can be requested from the power supply determined based on the sum of the target charging currents of each battery pack is smaller than the charging current that can be requested from the power supply determined by using the proportional control algorithm. The charging current requested by the power supply. By determining the first candidate charging current as the target parallel charging current, it can be ensured that when the power supply is requested to provide the target parallel charging current, the actual charging current allocated to each battery pack will not exceed the required charging current, and therefore no occurrence of Battery pack overcurrent problem.

Step S434: If the first candidate charging current is greater than or equal to the second candidate charging current, determine the second candidate charging current as the target parallel charging current.

If the first candidate charging current is greater than or equal to the second candidate charging current, it means that the charging current determined based on the sum of the target charging currents of each battery pack that can be requested from the power supply is greater than or equal to that determined using the proportional control algorithm. The charging current can be requested from the power supply. At this time, by determining the second candidate charging current as the target parallel charging current, it can be ensured that when the power supply is requested to provide the target parallel charging current, the actual charging current allocated to each battery pack will not exceed the required charging current. This avoids overcurrent problems.

It can be seen that in the process illustrated above, a proportional control algorithm is also combined to control the process of parallel charging of multiple battery packs. By comparing the size of the first candidate charging current and the second candidate charging current, The most appropriate target parallel charging current is finally determined, and the final determined target parallel charging current must be the smaller one of the first candidate charging current and the second candidate charging current to ensure that the battery pack does not occur. Charging overcurrent problem.

As another exemplary implementation, the process of determining the target parallel charging current according to the target charging current of each battery pack in step S430 is: summing the target charging currents of each battery pack, and determining the summation result as the target parallel charging current. machine charging current. It can be seen that in this embodiment, the process of parallel charging of multiple battery packs does not use a proportional control algorithm, but directly uses the sum of the target charging currents of each battery pack obtained in step S420 as the target parallel charging current. The power supply requests charging current, which not only ensures that no overcurrent problem occurs, but also reduces the controller's computing resource consumption.

As another exemplary implementation, as shown in FIG. 7 , the process of determining the target parallel charging current according to the target charging current of each battery pack in step S430 may also include the following steps S435-S437.

Step S435: Determine the parallel charging current according to the historical parallel charging current and the proportional control algorithm. The historical parallel charging current is the target parallel charging current determined last time.

The process of determining the parallel charging current based on the historical parallel charging current and the proportional control algorithm is consistent with the process of determining the second candidate charging current in step S432, and will not be described again here.

Step S436: When the battery pack has not entered the parallel charging steady state, the parallel charging current is determined as the target parallel charging current.

When the battery pack does not enter the parallel charging steady state, since the actual charging current of the battery pack is in a gradually rising stage, the problem of battery pack overcurrent usually does not occur. Therefore, the parallel charging current obtained in step S435 can be determined. As the target parallel charging current, that is, the parallel charging current determined based on the proportional control algorithm is used as the target parallel charging current to request charging from the power supply.

Step S437: When the battery pack enters the parallel charging steady state, compare the parallel charging current with the actual charging current of the multiple battery packs; if the difference between the parallel charging current and the actual charging current of the multiple battery packs is greater than the preset current difference , the target charging current of each battery pack is summed to obtain the target parallel charging current; if the difference between the parallel charging current and the actual charging current of multiple battery packs is less than the preset current difference, the parallel charging current is determined as Target parallel charging current.

When the battery pack enters the parallel charging steady state, that is, when the actual charging current of the reference battery pack is infinitely close to the required charging current of the reference battery pack, the parallel charging current needs to be compared with the actual charging current of the multi-battery pack. The actual charging current of a multi-battery pack is understood to be the sum of the actual charging currents of each battery pack.

If the difference between the parallel charging current and the actual charging current of the multi-battery pack is greater than the preset current difference, for example, 5A, it means that the parallel charging current determined based on the proportional control algorithm far exceeds that of the multi-battery pack. If the parallel charging current is used to request the power supply to provide charging current, it will easily cause overcurrent problems. Therefore, the target parallel charging current is obtained by summing the target charging currents of each battery pack.

If the difference between the parallel charging current and the actual charging current of the multi-battery pack is less than the preset current difference, it means that using the parallel charging current determined by the proportional control algorithm to request the power supply to provide charging current will not cause overcurrent problems. Therefore, The parallel charging current can also be used to request charging current from the power supply.

It can be seen from the above process that this embodiment still combines a proportional control algorithm to control the process of parallel charging of multiple battery packs, and also determines whether to use the sum of target charging currents as the target parallel charging based on different charging states. current, and finally a suitable current can be selected as the final target parallel charging current to ensure that the battery pack will not have overcurrent problems.

It should be noted that the method for determining the target parallel charging current in the above example can be selected according to actual application requirements, and this embodiment does not limit this.

It can be seen from the above embodiments that the technical solution provided by the embodiments of the present application can accurately and dynamically calculate the target charging current when each battery pack reaches the parallel charging steady state during the parallel charging process of multiple battery packs, and calculate the target charging current. As feedback to the power supply to request adjustment of the charging current, and when the output capability of the power supply changes, the charging current of each battery pack will not suddenly increase, causing the battery pack to repeatedly overcurrent, ensuring the safest situation. Use the maximum current to charge the battery pack most quickly.

Please refer to FIG. 8 , which is a block diagram of another exemplary parallel charging control device for multiple battery packs of the present application. The device is applied to a controller, and the controller establishes communication connections with each battery pack. As shown in FIG. 8 , the device includes a reference battery pack determination module 510 , a target charging current calculation module 520 , a target parallel charging current determination module 530 and a target charging instruction sending module 540 .

The reference battery pack determination module 510 is configured to calculate the charging current difference between the required charging current of each battery pack and the actual charging current of each battery pack, and determine the battery pack with the smallest charging current difference as the reference battery pack.

The target charging current calculation module 520 is configured to calculate the target charging current of each battery pack in the steady state of parallel charging based on the demand charging current of the reference battery pack and the actual charging current value of each battery pack. Wherein, when the battery pack is in the parallel charging steady state, the charging current difference of the reference battery pack is less than the preset current threshold.

The target parallel charging current determining module 530 is configured to determine the target parallel charging current according to the target charging current of each battery pack.

The target charging instruction sending module 540 is configured to generate a target charging instruction according to the target parallel charging current, and send the target charging instruction to the power supply. The target charging instruction is used to instruct the power supply to output the target parallel charging current to charge the multiple battery packs.

In another exemplary embodiment, the target charging current calculation module 520 includes a target charging current determination unit, a proportional relationship calculation unit, and a target charging current calculation unit.

The target charging current determining unit is configured to use the demand charging current of the reference battery pack as the target charging current of the reference battery pack in the parallel charging steady state.

The proportional relationship calculation unit is configured to calculate a proportional relationship between the actual charging current of the reference battery pack and the actual charging current of the target battery pack.

The target charging current calculation unit is configured to calculate the target charging current of each target battery pack in the steady state of parallel charging based on the proportional relationship and the target charging current of the reference battery pack. The target battery pack is any of the multi-battery packs except the reference battery pack. One battery pack.

In another exemplary embodiment, the target parallel charging current determining module 530 includes a first candidate charging current determining unit, a second candidate charging current determining unit and a target determining unit.

The first candidate charging current determining unit is configured to determine the first candidate charging current according to the target charging current of each battery pack.

The second candidate charging current determining unit is configured to determine the second candidate charging current according to the historical parallel charging current and the proportional control algorithm, where the historical parallel charging current is the last determined target parallel charging current.

The target determination unit is configured to determine the first candidate charging current as the target parallel charging current if the first candidate charging current is less than the second candidate charging current; if the first candidate charging current is greater than or equal to the second candidate charging current, then determine the first candidate charging current as the target parallel charging current. The second candidate charging current is determined as the target parallel charging current.

In another exemplary embodiment, the target parallel charging current determination module 530 is configured to sum the target charging currents of each battery pack, and determine that the summation result is the target parallel charging current.

In another exemplary embodiment, the target parallel charging current determining module 530 includes a parallel charging current determining unit and a target switching selection unit.

The parallel charging current determination unit is configured to determine the parallel charging current based on the historical parallel charging current and the proportional control algorithm, where the historical parallel charging current is the last determined target parallel charging current.

The target switching selection unit is configured to determine the parallel charging current as the target parallel charging current when the battery pack does not enter the parallel charging steady state; when the battery pack enters the parallel charging steady state, compare the parallel charging current with the multi-battery The actual charging current of the battery pack; if the difference between the parallel charging current and the actual charging current of multiple battery packs is greater than the preset current difference, the target charging current of each battery pack is summed to obtain the target parallel charging current; if the parallel charging current If the difference between the charging current and the actual charging current of the multi-battery pack is less than the preset current difference, the parallel charging current is determined as the target parallel charging current.

In another exemplary embodiment, the device further includes:

The mode determination module is configured to receive the heartbeat information sent by each battery pack, and determine the number of connected battery packs based on the heartbeat information, and if the number is greater than 1, jump to the reference battery pack determination module 510.

It should be noted that the parallel charging control device for multiple battery packs provided by the above embodiments and the parallel charging control method for multiple battery packs provided by the above embodiments belong to the same concept, and the specific manner in which each module and unit performs operations is It has been described in detail in the method embodiment and will not be described again here. In practical applications of the parallel charging control device for multiple battery packs provided in the above embodiments, the above function allocation can be completed by different functional modules as needed, that is, the internal structure of the device is divided into different functional modules to complete the above. All or part of the functions described are not limited here.

The parallel charging control device for multiple battery packs provided in the above embodiment can accurately and dynamically calculate the target charging current when each battery pack reaches the parallel charging steady state during the parallel charging process of multiple battery packs, and use it as feedback. The power supply is requested to adjust the charging current, and when the output capability of the power supply changes, the charging current of each battery pack will not suddenly increase, causing repeated overcurrent of the battery pack, ensuring the safest use of the battery pack. The maximum current charges the battery pack the fastest.

The embodiment of the present application also provides an energy storage device. As shown in Figure 9 , an exemplary energy storage device 600 includes: a parallel port 610, a controller 620, a memory 630, and at least one battery pack 640.

The parallel port 610 is used to provide the parallel function of the energy storage device 600, such as connecting to other energy storage devices or independent battery packs. For example, as shown in FIG. 9 , the energy storage device 600 can be connected in parallel with the independent battery pack 700 through the parallel port 610 . When the energy storage device 600 is in a charging state, the parallel charging scenario of multiple battery packs is realized.

The controller 620 establishes connections with each battery pack. It should be noted that the controller 620 may be in the energy storage device 600 , or may be outside the energy storage device 600 . For example, the controller 620 may be provided in a battery pack incorporated through the parallel port 610 . When the controller 620 is provided in the energy storage device 600, the controller 620 is not only connected to each battery pack 640 in the energy storage device 600, but also connected to the incorporated battery pack or other incorporated energy storage devices through the parallel port 610. battery pack connection. When the controller 620 is installed outside the energy storage device 600, the controller 620 is connected to each battery pack 640 in the energy storage device 600 through the parallel port 610.

The memory 630 stores computer readable instructions and is connected to the controller 620. When the computer readable instructions are executed by the controller 620, the energy storage device implements the parallel charging control method for multiple battery packs provided in the above embodiments. , to ensure that there will be no overcurrent problem in the battery pack during parallel charging.

It can be understood that the memory is, for example, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact Disk read-only memory (Compact Disc Read-Only Memory, CD-ROM), optical storage device, magnetic storage device, etc. This embodiment is not limited here.

Some embodiments of the present application also provide an energy storage system, which includes at least two energy storage devices connected through a parallel port, and at least one of the energy storage devices is the energy storage device as described above. . Still taking Figure 9 as an example, two energy storage devices 600 are connected through their respective parallel ports 610, and the battery packs in the two energy storage devices are paralleled to form a multi-battery pack. At this time, any controller 620 of the energy storage device 600 can be selected as the main controller to execute the parallel charging current control method of multiple battery packs as described above.

Another aspect of the present application also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the parallel charging control method of multiple battery packs is implemented as described above. The computer-readable storage medium may be included in the energy storage device described in the above embodiments, or may exist separately without being assembled into the energy storage device.

The computer-readable medium shown in the embodiments of the present application may be a computer-readable signal medium or a computer-readable storage medium, or any combination of the above two. The computer-readable storage medium may be, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination thereof. More specific examples of computer readable storage media may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard drive, random access memory (RAM), read only memory (ROM), removable Programmable Read-Only Memory (Erasable Programmable Read Only Memory, EPROM), flash memory, optical fiber, portable compact disk read-only memory (Compact Disc Read-Only Memory, CD-ROM), optical storage device, magnetic storage device, or any of the above suitable combination, this embodiment is not limited to this.

The above content is only a preferred exemplary embodiment of the present application and is not intended to limit the implementation of the present application. Those of ordinary skill in the art can easily make corresponding modifications or modifications based on the main concept and spirit of the present application. Therefore, the protection scope of this application should be subject to the protection scope required by the claims.

Claims

A parallel charging control method for multiple battery packs, applied to a controller. The controller establishes a communication connection with each battery pack. The parallel charging control method includes:

Calculate the charging current difference between the required charging current of each battery pack and the actual charging current of each battery pack, and determine the battery pack with the smallest charging current difference as the reference battery pack;

According to the demand charging current of the reference battery pack and the actual charging current value of each battery pack, the target charging current of each battery pack in the parallel charging steady state is calculated; wherein, the battery pack is in the parallel charging stable state. state, the charging current difference of the reference battery pack is less than the preset current threshold;

Determine the target parallel charging current according to the target charging current of each battery pack;

Generate a target charging instruction according to the target parallel charging current, and send the target charging instruction to the power supply. The target charging instruction is used to instruct the power supply to output the target parallel charging current to charge the multi-battery pack. .
The method according to claim 1, wherein the target charging of each battery pack in parallel charging steady state is calculated based on the demand charging current of the reference battery pack and the actual charging current value of each battery pack. Current, including:

The demand charging current of the reference battery pack is used as the target charging current of the reference battery pack in the steady state of parallel charging;

Calculate the proportional relationship between the actual charging current of the reference battery pack and the actual charging current of the target battery pack;

According to the proportional relationship and the target charging current of the reference battery pack, the target charging current of each target battery pack in the parallel charging steady state is calculated. The target battery pack is one of the multiple battery packs except the reference battery pack. Any battery pack other than
The method according to claim 1, wherein determining the target parallel charging current according to the target charging current of each battery pack includes:

Determine the first candidate charging current according to the target charging current of each battery pack;

Determine the second candidate charging current according to the historical parallel charging current and the proportional control algorithm, where the historical parallel charging current is the last determined target parallel charging current;

If the first candidate charging current is less than the second candidate charging current, determine the first candidate charging current as the target parallel charging current;

If the first candidate charging current is greater than or equal to the second candidate charging current, the second candidate charging current is determined as the target parallel charging current.
The method according to claim 1, wherein determining the target parallel charging current according to the target charging current of each battery pack includes:

The target charging currents of each of the battery packs are summed, and the summation result is determined to be the target parallel charging current.
The method according to claim 1, wherein determining the target parallel charging current according to the target charging current of each battery pack includes:

The parallel charging current is determined according to the historical parallel charging current and the proportional control algorithm, where the historical parallel charging current is the target parallel charging current determined last time;

When the battery pack does not enter the parallel charging steady state, determine the parallel charging current as the target parallel charging current;

When the battery pack enters the parallel charging steady state, compare the parallel charging current with the actual charging current of the multi-battery pack; if the difference between the parallel charging current and the actual charging current of the multi-battery pack is greater than The current difference is preset, and the target charging currents of each battery pack are summed to obtain the target parallel charging current.
The method according to claim 5, wherein determining the target parallel charging current according to the target charging current of each battery pack further includes:

If the difference between the parallel charging current and the actual charging current of the multi-battery pack is less than the preset current difference, the parallel charging current is determined as the target parallel charging current.
The method according to claim 1, wherein the parallel charging control method further includes:

Receive heartbeat information sent by each battery pack;

Determine the number of connected battery packs based on the heartbeat information;

If the number is greater than 1, perform the calculation of the charging current difference between the required charging current of each battery pack and the actual charging current of each battery pack, and determine the battery pack with the smallest charging current difference as the reference. Battery Pack Steps.
The method according to claim 1, wherein in said separately calculating the charging current difference between the required charging current of each of the battery packs and the actual charging current of each of the battery packs, the battery pack with the smallest charging current difference is Before determining the reference battery pack, the method further includes:

When entering parallel charging, an instruction is generated based on the preset initial parallel charging current and sent to the power supply.
An energy storage device, the energy storage device includes a parallel port, a controller, a memory and a battery pack;

The parallel port is used to connect to other energy storage devices or independent battery packs;

The controller establishes a connection with each battery pack;

Computer-readable instructions are stored on the memory. When the computer-readable instructions are executed by the controller, the method according to any one of claims 1-8 is implemented.
An energy storage system includes at least two energy storage devices connected through a parallel port, and at least one of the energy storage devices is the energy storage device as claimed in claim 9.