Control method of battery system, power converter and energy storage system

Abstract

The invention provides a control method of a battery system, a power converter and an energy storage system, and relates to the technical field of battery control. When the actual temperature of the battery system is higher than the allowable maximum temperature thereof, the determined target adjustment power of the battery system is lower than the given power thereof, so that when the actual temperature is higher than the allowable maximum temperature, the battery system charges and discharges at a power lower than the given power. Furthermore, when the actual temperature is lower than the allowable maximum temperature, the determined target adjustment power is higher than the predetermined power, and when the actual temperature is lower than the allowable maximum temperature, the battery system charges and discharges at a power higher than the predetermined power. In conclusion, the control method can enable the average power of the battery system to be close to the given power, so that the control method can reduce the unbalance degree among the service lives of the battery systems.

Description

Technical Field

[0001] The present invention relates to the technical field of battery control, and in particular to a control method for a battery system, a power converter and an energy storage system. Background Art

[0002] At present, in the application scenarios of small-power photovoltaic energy storage systems, since the energy storage needs of each household are not consistent, the battery system in the small-power photovoltaic energy storage system is usually separate and scalable, such as Figure 1 As shown. Figure 1 In the embodiment, battery system 1, battery system 2 and battery system 3 are connected to the hybrid inverter via interconnection cables, and the three battery systems are stacked up and down in structure.

[0003] Due to the differences in structural stacking forms and user installation locations, different battery systems may have different heat dissipation conditions, that is, different battery systems may have different temperatures. Therefore, a battery system with poor heat dissipation conditions may be frequently derated, resulting in a battery system with good heat dissipation conditions having a greater life loss than the battery system, thereby causing individual battery systems to fail prematurely.

[0004] Therefore, how to reduce the imbalance between the life spans of various battery systems is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of this, the present invention provides a control method for a battery system, a power converter and an energy storage system to reduce the imbalance between the life spans of various battery systems.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] A first aspect of the present application provides a control method for a battery system, comprising:

[0008] Determine a target adjustment power of the battery system; when the actual temperature of the battery system is higher than the maximum allowable temperature of the battery system, the target adjustment power is lower than the given power of the battery system, and when the actual temperature is lower than the maximum allowable temperature, the target adjustment power is higher than the given power;

[0009] The power of the battery system is adjusted according to the target adjustment power.

[0010] Optionally, determining a target adjustment power of the battery system includes:

[0011] Determine a pre-compensation power according to a deviation of the actual temperature relative to the maximum allowable temperature; when the actual temperature is higher than the maximum allowable temperature, the pre-compensation power is less than zero, and when the actual temperature is lower than the maximum allowable temperature, the pre-compensation power is greater than zero;

[0012] The sum of the pre-compensation power and the given power is determined as the target adjustment power.

[0013] Optionally, before determining the sum of the pre-compensation power and the given power of the battery system as the target adjustment power, the method further includes:

[0014] Determine a power difference; the power difference is the difference between the actual total power transferred by the battery system and the nominal power; the nominal power is the total power transferred by the battery system at the given power;

[0015] When the pre-compensation power is less than zero and the power difference is less than or equal to a first preset value, the power of the battery system is adjusted according to the given power; the first preset value is a value less than zero;

[0016] and / or,

[0017] When the pre-compensation power is greater than zero and the power difference is greater than or equal to a second preset value, the power of the battery system is adjusted according to the given power; the second preset value is a value greater than or equal to zero.

[0018] Optionally, determining the power difference includes:

[0019] Determine the product of the pre-compensation power and the execution period of the control method of the battery system as pre-compensation electric energy;

[0020] The last electric quantity difference value is obtained, and the electric quantity difference value is updated to the sum of the pre-compensated electric energy and the last electric quantity difference value.

[0021] Optionally, after updating the power difference to the sum of the pre-compensated electric energy and the power difference, determining the power difference further includes:

[0022] The power difference is limited.

[0023] Optionally, limiting the power difference includes:

[0024] When the power difference is less than a third preset value, updating the power difference to the third preset value; the third preset value is a value less than zero;

[0025] When the power difference is greater than a fourth preset value, the power difference is updated to the fourth preset value; the fourth preset value is a value greater than or equal to zero.

[0026] Optionally, the third preset value is equal to the first preset value;

[0027] The fourth preset value is equal to the second preset value.

[0028] A second aspect of the present application provides a power converter, comprising: a main circuit and a controller; wherein:

[0029] At least one battery system is connected to the first side of the main circuit;

[0030] The main circuit is controlled by the controller, and the controller is used to execute the control method of the battery system as described in any one of the first aspects of the present application on the battery system.

[0031] A third aspect of the present application provides an energy storage system, comprising: at least one battery system and a power converter as described in the third aspect of the present application.

[0032] Optionally, the power converter is an inverter, and the second side of the main circuit in the power converter is connected to a photovoltaic device.

[0033] It can be seen from the above technical solution that the present invention provides a control method for a battery system. In the control method, since the target adjustment power of the battery system is determined to be lower than the given power of the battery system when the actual temperature of the battery system is higher than the maximum allowable temperature of the battery system, the battery system is charged and discharged at a power lower than the given power when the actual temperature is higher than the maximum allowable temperature. In addition, since the target adjustment power is determined to be higher than the given power when the actual temperature is lower than the maximum allowable temperature, the battery system is charged and discharged at a power higher than the given power when the actual temperature is lower than the maximum allowable temperature. In summary, the control method can make the average power of the battery system close to the given power, so that the control method can make the life loss of the battery system close to the life loss of charging and discharging at the given power, and then the control method can reduce the degree of imbalance between the lifespans of the battery systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1-Figure 5 Schematic diagrams of five implementations of the control method of the battery system provided in the embodiments of the present application;

[0036] Figure 6-Figure 8 Schematic diagrams of the three implementation methods of determining the power difference provided in the embodiments of the present application;

[0037] Fig. 9 A schematic diagram of the structure of the energy storage system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] In this application, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0040] In order to reduce the imbalance between the life spans of various battery systems, the present application provides a method for controlling a battery system, and the specific process is as follows: Figure 1 As shown, the specific steps include:

[0041] S110: Determine the target adjustment power of the battery system.

[0042] Among them, when the actual temperature of the battery system is higher than the maximum allowable temperature of the battery system, the above target adjustment power is lower than the given power of the battery system; when the above actual temperature is lower than the above maximum allowable temperature, the above target adjustment power is higher than the above given power.

[0043] In addition, the above-mentioned given power refers to the charging electric power set by the controller.

[0044] S120: Adjust the power of the battery system according to the above target power adjustment.

[0045] In this embodiment, since the target adjustment power of the battery system determined is lower than the given power of the battery system when the actual temperature of the battery system is higher than the maximum allowable temperature of the battery system, the battery system is charged and discharged at a power lower than the given power when the actual temperature is higher than the maximum allowable temperature. In addition, since the target adjustment power determined is higher than the given power when the actual temperature is lower than the maximum allowable temperature, the battery system is charged and discharged at a power higher than the given power when the actual temperature is lower than the maximum allowable temperature. In summary, the control method can make the average power of the battery system close to the given power, so that the control method can make the life loss of the battery system close to the life loss of charging and discharging at the given power, and further the control method can reduce the degree of imbalance between the lifespans of the battery systems.

[0046] Another embodiment of the present application provides a specific implementation of step S110, and the specific process is as follows: Figure 2 As shown, the specific steps include:

[0047] S210: Determine a pre-compensation power according to a deviation of the actual temperature relative to the maximum allowable temperature.

[0048] Wherein, when the actual temperature is higher than the maximum allowable temperature, the pre-compensation power is less than zero, and when the actual temperature is lower than the maximum allowable temperature, the pre-compensation power is greater than zero.

[0049] In a specific example, the deviation of the actual temperature relative to the maximum allowable temperature is used as an input of a PI controller, and the output of the PI controller is the pre-compensation power.

[0050] It should be noted that the PI controller is already very mature in the prior art and will not be described in detail here.

[0051] The above example only shows a specific implementation of step S210. In practical applications, including but not limited to this, as long as the implementation method of determining the pre-compensation power based on the deviation of the above actual temperature relative to the above allowable maximum temperature is within the protection scope of this application, such as using a PID controller. No specific limitation is made here and it can be determined according to the specific situation.

[0052] S220: Determine the sum of the pre-compensation power and the given power as the target adjustment power.

[0053] In this embodiment, since the pre-compensation power is less than zero when the actual temperature is higher than the maximum allowable temperature, the target adjustment power is lower than the given power when the actual temperature is higher than the maximum allowable temperature. Therefore, this embodiment can make the target adjustment power lower than the given power when the actual temperature is higher than the maximum allowable temperature. In addition, since the pre-compensation power is greater than zero when the actual temperature is lower than the maximum allowable temperature, the target adjustment power is higher than the given power when the actual temperature is lower than the maximum allowable temperature. Therefore, this embodiment can make the target adjustment power higher than the given power when the actual temperature is lower than the maximum allowable temperature.

[0054] The above is only a specific implementation of step S110. In practical applications, including but not limited to this, as long as the implementation method of the above target adjustment power can be determined, it is within the protection scope of this application.

[0055] Another embodiment of the present application provides another specific implementation of step S110, and its specific process is as follows: Figure 3 As shown, this embodiment further includes the following steps before step S220 in the previous embodiment:

[0056] S310: Determine the power difference.

[0057] The power difference is the difference between the actual total power transferred by the battery system and the nominal power. The nominal power is the total power transferred by the battery system at the above given power.

[0058] For example, assuming that the battery system is charged and discharged at power P1 in the time period t1~t2, and is charged and discharged at power P2 in the time period t2~t3, and the given power is P0, then the actual total electric energy transferred by the battery system in the time period t1~t3 is Etotal=P1×(t2-t1)+P2×(t3-t2), and the nominal electric energy Estandard=P0×(t3-t1), so the electric energy difference ΔE=Etotal-Estandard=P1×(t2-t1)+P2×(t3-t2)-P0×(t3-t1).

[0059] Since the power difference is the difference between the actual total power transferred by the battery system and the nominal power, if the power difference is less than 0, the battery system charges and discharges at a power lower than the above given power for a longer time than the battery system charges and discharges at a power higher than the above given power. In other words, the battery system is in a derated state for a longer time than the battery system is in an increased state, that is, the battery system has a shorter lifespan. Conversely, if the power difference is greater than 0, the battery system charges and discharges at a power higher than the above given power for a longer time than the battery system charges and discharges at a power lower than the above given power. In other words, the battery system is in an increased state for a longer time than the battery system is in a derated state, that is, the battery system has a shorter lifespan.

[0060] S320: Determine whether the pre-compensation power is less than zero, and whether the power difference is less than or equal to a first preset value.

[0061] If the pre-compensation power is less than zero and the power difference is less than or equal to the first preset value, execute step S330; if the pre-compensation power is greater than or equal to zero, and / or the power difference is greater than the first preset value, execute step S220.

[0062] The first preset value is a value less than zero.

[0063] Since the first preset value is a value less than zero, the power difference is less than the first preset value, indicating that the time when the battery system is charged and discharged at a power lower than the above given power is very different from the time when the battery system is charged and discharged at a power higher than the above given power. In other words, the time when the battery system is in a derated state is very different from the time when the battery system is in an increased state, that is, the life loss of the battery system is very small. Conversely, the power difference is greater than or equal to the first preset value, indicating that the time when the battery system is charged and discharged at a power lower than the above given power is not very different from the time when the battery system is charged and discharged at a power higher than the above given power. In other words, the time when the battery system is in a derated state is not very different from the time when the battery system is in an increased state, that is, the life loss of the battery system is not very small. In practical applications, the first preset value is set according to specific circumstances. Generally, the first preset value is equal to 10 times the capacity of the battery system.

[0064] It can be seen from the above that if the pre-compensation power is less than zero, the determined target adjustment power is lower than the given power, so the battery system will be charged and discharged at a power lower than the given power.

[0065] S330: Adjust the power of the battery system according to the given power.

[0066] In this embodiment, since the pre-compensation power is less than zero, it indicates that the battery system will be charged and discharged at a power lower than the above-mentioned given power, and the power difference is less than the first preset value, it indicates that the life loss of the battery system is very small. Therefore, in this implementation mode, when the life loss of the battery system is very small and the battery system will be charged and discharged at a power lower than the above-mentioned given power, the power of the battery system is adjusted according to the above-mentioned given power, that is, the battery system will be charged and discharged at the above-mentioned given power, thereby avoiding the battery system from being in a derating state when the battery system is in an area with relatively high temperature or the heat dissipation conditions of the battery system are particularly poor.

[0067] The above is only a specific implementation of step S110. In practical applications, including but not limited to this, no specific limitation is made here and it may be determined according to the specific situation, all of which are within the protection scope of this application.

[0068] Another embodiment of the present application provides another specific implementation of step S110, and its specific process is as follows: Figure 4 As shown, this embodiment further includes the following steps before step S220 in the previous embodiment:

[0069] S410: Determine the power difference.

[0070] The power difference is the difference between the actual total power transferred by the battery system and the nominal power. The nominal power is the total power transferred by the battery system at the above given power.

[0071] It should be noted that the power difference has been described in detail in the above embodiment and will not be repeated here.

[0072] S420: Determine whether the compensation power is greater than zero, and whether the power difference is greater than or equal to a second preset value.

[0073] If the pre-compensation power is greater than zero and the power difference is greater than or equal to the second preset value, execute step S430; if the pre-compensation power is less than or equal to zero, and / or the power difference is less than the second preset value, execute step S220.

[0074] The second preset value is a value greater than or equal to zero.

[0075] Since the second preset value is a value greater than or equal to zero, the power difference is greater than or equal to the second preset value, indicating that the time when the battery system is charged and discharged at a power higher than the above given power is very different from the time when the battery system is charged and discharged at a power lower than the above given power. In other words, the time when the battery system is in the increased capacity state is very different from the time when the battery system is in the reduced capacity state, that is, the life loss of the battery system is large. Conversely, the power difference is less than the second preset value, indicating that the time when the battery system is charged and discharged at a power higher than the above given power is not very different from the time when the battery system is charged and discharged at a power lower than the above given power. In other words, the time when the battery system is in the increased capacity state is not very different from the time when the battery system is in the reduced capacity state, that is, the life loss of the battery system is not large.

[0076] In practical applications, the second preset value is set according to specific circumstances. Usually, the second preset value is equal to 0.

[0077] It can be seen from the above that if the pre-compensation power is greater than zero, the determined target adjustment power is higher than the given power, so the battery system will be charged and discharged at a power higher than the given power.

[0078] S430: Adjust the power of the battery system according to the given power.

[0079] In this embodiment, since the pre-compensation power is greater than zero, indicating that the battery system will be charged and discharged at a power higher than the above-mentioned given power, and the power difference is greater than or equal to the second preset value, indicating that the battery system has a lot of life loss. Therefore, in this embodiment, when the battery system has a lot of life loss and the battery system will be charged and discharged at a power higher than the above-mentioned given power, the power of the battery system is adjusted according to the above-mentioned given power, that is, the battery system will be charged and discharged at the above-mentioned given power, thereby avoiding the battery system from being in an overload state all the time when the battery system is in an area with relatively low temperature or the heat dissipation conditions of the battery system are particularly good.

[0080] In addition, when the second preset value is equal to 0, if the pre-compensation power is greater than zero, the battery system will be charged and discharged at the above-mentioned given power; if the pre-compensation power is less than zero, step S220 is executed, that is, the battery system will be charged and discharged at a power lower than the above-mentioned given power. Therefore, when the second preset value is equal to 0, as long as the heat dissipation conditions permit, this embodiment can enable the battery system to be stably charged and discharged at the above-mentioned given power, so that this embodiment can stabilize the life loss of the battery system at approximately the life loss of charging and discharging at the above-mentioned given power, and thus the control method can further reduce the imbalance between the lifespans of the battery systems.

[0081] The above is only a specific implementation of step S110. In practical applications, including but not limited to this, no specific limitation is made here and it may be determined according to the specific situation, all of which are within the protection scope of this application.

[0082] Another embodiment of the present application provides another specific implementation of step S110, and its specific process is as follows: Figure 5 As shown, this embodiment further includes the following steps before step S220 in the previous embodiment:

[0083] S510: Determine the power difference.

[0084] The power difference is the difference between the actual total power transferred by the battery system and the nominal power. The nominal power is the total power transferred by the battery system at a given power.

[0085] It should be noted that the power difference has been described in detail in the above embodiment and will not be repeated here.

[0086] S520: Determine whether the pre-compensation power is less than zero, and whether the power difference is less than or equal to a first preset value.

[0087] If the pre-compensation power is less than zero and the power difference is less than or equal to the first preset value, execute step S530; if the pre-compensation power is greater than or equal to zero, and / or the power difference is greater than the first preset value, execute step S540.

[0088] The first preset value is a value less than zero.

[0089] It should be noted that the meaning of the power difference being less than the first preset value has been described in detail in the above embodiment and will not be repeated here.

[0090] S530: Adjust the power of the battery system according to the given power.

[0091] S540: Determine whether the compensation power is greater than zero, and whether the power difference is greater than or equal to a second preset value.

[0092] If the pre-compensation power is greater than zero and the power difference is greater than or equal to the second preset value, execute step S530; if the pre-compensation power is less than or equal to zero, and / or the power difference is less than the second preset value, execute step S220.

[0093] The second preset value is a value greater than or equal to 0. In practical applications, the second preset value is set according to specific circumstances. Usually, the second preset value is equal to 0.

[0094] It should be noted that the meaning of the power difference being greater than or equal to the second preset value has been described in detail in the above embodiment and will not be repeated here.

[0095] In this embodiment, since this embodiment performs the step of adjusting the power of the battery system according to the above-mentioned given power when the pre-compensation power is less than zero and the power difference is less than or equal to the first preset value, or when the pre-compensation power is greater than zero and the power difference is greater than or equal to the second preset value, it can be seen from the above two embodiments that this embodiment can prevent the battery system from being in a derating state when the battery system is in an area with relatively high temperature or the heat dissipation conditions of the battery system are particularly poor, and can also prevent the battery system from being in an increasing state when the battery system is in an area with relatively low temperature or the heat dissipation conditions of the battery system are particularly good.

[0096] In addition, when the second preset value is equal to 0, if the pre-compensation power is greater than zero, the battery system will be charged and discharged at the above-mentioned given power; if the pre-compensation power is less than zero, step S220 is executed, that is, the battery system will be charged and discharged at a power lower than the above-mentioned given power. Therefore, when the second preset value is equal to 0, as long as the heat dissipation conditions permit, this embodiment can enable the battery system to be stably charged and discharged at the above-mentioned given power, so that this embodiment can stabilize the life loss of the battery system at approximately the life loss of charging and discharging at the above-mentioned given power, and thus the control method can further reduce the imbalance between the lifespans of the battery systems.

[0097] In practical applications, the execution order of step S520 and step S540 is Figure 5 In addition to this form, it can also be: first execute step S540, and then execute step S520 when the pre-compensation power is less than or equal to zero and / or the power difference is less than a second preset value; it can also be: execute step S520 and step S540 at the same time, and stop executing the control method when the pre-compensation power is greater than or equal to zero and / or the power difference is greater than the first preset value and when the pre-compensation power is less than or equal to zero and / or the power difference is less than the second preset value. No specific limitation is made here, it can be determined according to the specific circumstances, and it is all within the protection scope of this application.

[0098] The above is only a specific implementation of step S110. In practical applications, including but not limited to this, no specific limitation is made here and it may be determined according to the specific situation, all of which are within the protection scope of this application.

[0099] Another embodiment of the present application provides a specific implementation method for determining the power difference, and the specific process is as follows: Figure 6 As shown, the specific steps include:

[0100] S610: Determine the product of the pre-compensation power and the execution period of the control method of the battery system as the pre-compensation electric energy.

[0101] S620: Obtain the last power difference, and update the power difference to the sum of the pre-compensated electric energy and the last power difference.

[0102] Step S610 and step S620 can be calculated according to the following formula, which is described in detail as follows:

[0103] E(k)=E(k-1)+P*Ts

[0104] Wherein, Ts is the execution cycle of the control method of the battery system; E(k) is the power difference calculated in the kth execution cycle, that is, the power difference value; E(k-1) is the power difference calculated in the k-1th execution cycle, that is, the previous power difference value; P is the pre-compensation power.

[0105] In practical applications, the determined power difference is usually stored in a non-volatile memory, and the power difference can be reread from the non-volatile memory after each power-on. Thus, in the case of multiple power-ons and power-offs, the life loss of the battery system can be made close to the life loss of charging and discharging at the above-mentioned given power, thereby reducing the imbalance between the lifespans of the battery systems in the case of multiple power-ons and power-offs.

[0106] In addition, since the system where the battery system is located generally includes a non-volatile memory, the power difference can be directly stored in the non-volatile memory of the system where the battery system is located, so there is no need to increase the hardware cost.

[0107] The above is only a specific implementation method for determining the power difference. In practical applications, including but not limited to this, no specific limitation is made here and it can be determined according to the specific circumstances, all of which are within the protection scope of this application.

[0108] Another embodiment of the present application provides another specific implementation method for determining the power difference, and the specific process is as follows: Figure 7 As shown, this embodiment further includes the following steps after step S620 in the previous embodiment:

[0109] S710: Limit the power difference.

[0110] In this embodiment, since the charge difference is limited, if the battery system is originally in an area with relatively high temperature or the heat dissipation conditions of the battery system are particularly poor, or the battery system is originally in an area with relatively low temperature or the heat dissipation conditions of the battery system are particularly good, but its current environment changes or its current heat dissipation conditions change, the charge difference can respond quickly, for example, after several of the above execution cycles, the charge difference changes from less than zero to greater than or equal to zero, thereby improving the rapid response of the control method.

[0111] Another embodiment of the present application provides a specific implementation of step S710, and the specific process is as follows: Figure 8 As shown, the specific steps include:

[0112] S810: Determine whether the power difference is less than a third preset value.

[0113] If the power difference is less than the third preset value, step S820 is executed; if the power difference is greater than or equal to the third preset value, step S830 is executed.

[0114] The third preset value is a value less than zero.

[0115] S820: Update the power difference to a third preset value.

[0116] S830: Determine whether the power difference is greater than a fourth preset value.

[0117] If the power difference is greater than the fourth preset value, step S840 is executed; if the power difference is less than or equal to the fourth preset value, the control method is stopped.

[0118] The fourth preset value is a value greater than or equal to zero.

[0119] 840. Update the power difference to a fourth preset value.

[0120] In a specific example, the third preset value is equal to the first preset value, and the fourth preset value is equal to the second preset value.

[0121] The above example only shows a specific implementation of the third preset value and the fourth preset value. In practical applications, including but not limited to this, no specific limitation is made here and it can be determined according to the specific circumstances, all of which are within the scope of protection of this application.

[0122] The above is only a specific implementation method for limiting the power difference. In practical applications, including but not limited to this, no specific limitation is made here. It can be determined according to the specific situation and is within the protection scope of this application.

[0123] Another embodiment of the present application is a power converter, and its specific structure can be seen in Fig. 9 ( Fig. 9 Only three battery systems are taken as an example for demonstration), specifically including: a main circuit 10 and a controller 20.

[0124] At least one battery system is connected to the first side of the main circuit 10. The main circuit 10 is controlled by a controller 20, and the controller 20 is used to execute the control method of the battery system provided in the above embodiment on the battery system.

[0125] In a specific example, if the number of battery systems is greater than 1, the battery systems are connected in series, such as Fig. 9shown.

[0126] The above example only shows a connection method of the battery system when the number of battery systems is greater than 1. In practical applications, including but not limited to this, as long as the method of connecting to the first side of the main circuit 10 is within the protection scope of this application, no specific limitation is made here, and it may depend on the specific situation and is within the protection scope of this application.

[0127] In this embodiment, since the controller is used to execute the control method of the battery system provided in the above embodiment, the power converter can make the life loss of the battery system close to the life loss of charging and discharging with the above given power, and thus the power converter can reduce the imbalance between the lifespans of each battery system.

[0128] Another embodiment of the present application provides an energy storage system, the specific structure of which can be seen in Fig. 9 , specifically comprising: at least one battery system 100 and a power converter 200 as provided in the above embodiment.

[0129] If the power converter 200 is an inverter, then Fig. 9 As shown, the second side of the main circuit 10 in the power converter 200 is connected to the photovoltaic device 300 .

[0130] In this embodiment, since the energy storage system includes the power converter 200 provided in the above embodiment, the energy storage system can make the life loss of the battery system close to the life loss of charging and discharging at the above given power, and thus the energy storage system can reduce the imbalance between the lifespans of the battery systems.

[0131] For the above description of the disclosed embodiments, the features recorded in each embodiment in this specification can be replaced or combined with each other, so that professionals in the field can implement or use the present application. The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with a preferred embodiment, it is not used to limit the present invention. Any technician familiar with the field can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for controlling a battery system, characterized in that: include: determining a target adjustment power of the battery system; When the actual temperature of the battery system is higher than the maximum allowable temperature of the battery system, the target adjusted power is lower than the given power of the battery system; when the actual temperature is lower than the maximum allowable temperature, the target adjusted power is higher than the given power; The power of the battery system is adjusted according to the target adjustment power.

2. The control method of the battery system according to claim 1, characterized in that: Determining a target adjustment power of the battery system includes: Determine a pre-compensation power according to a deviation of the actual temperature relative to the maximum allowable temperature; when the actual temperature is higher than the maximum allowable temperature, the pre-compensation power is less than zero, and when the actual temperature is lower than the maximum allowable temperature, the pre-compensation power is greater than zero; The sum of the pre-compensation power and the given power is determined as the target adjustment power.

3. The control method of the battery system according to claim 2, characterized in that: Before determining the sum of the pre-compensation power and the given power of the battery system as the target adjustment power, the method further includes: Determine a power difference; the power difference is the difference between the actual total power transferred by the battery system and the nominal power; the nominal power is the total power transferred by the battery system at the given power; When the pre-compensation power is less than zero and the power difference is less than or equal to a first preset value, the power of the battery system is adjusted according to the given power; the first preset value is a value less than zero; and / or, When the pre-compensation power is greater than zero and the power difference is greater than or equal to a second preset value, the power of the battery system is adjusted according to the given power; the second preset value is a value greater than or equal to zero.

4. The control method of the battery system according to claim 3, characterized in that: Determining the power difference includes: Determine the product of the pre-compensation power and the execution period of the control method of the battery system as pre-compensation electric energy; The last electric quantity difference value is obtained, and the electric quantity difference value is updated to the sum of the pre-compensated electric energy and the last electric quantity difference value.

5. The control method of the battery system according to claim 4, characterized in that: After updating the power difference to the sum of the pre-compensation electric energy and the power difference, determining the power difference further includes: The power difference is limited.

6. The control method of the battery system according to claim 5, characterized in that: Limiting the power difference includes: When the power difference is less than a third preset value, updating the power difference to the third preset value; the third preset value is a value less than zero; When the power difference is greater than a fourth preset value, the power difference is updated to the fourth preset value; the fourth preset value is a value greater than or equal to zero.

7. The control method of the battery system according to claim 6, characterized in that: The third preset value is equal to the first preset value; The fourth preset value is equal to the second preset value.

8. A power converter, characterized in that: include: Main circuit and controller; wherein: At least one battery system is connected to the first side of the main circuit; The main circuit is controlled by the controller, and the controller is used to execute the control method of the battery system as described in any one of claims 1 to 7 on the battery system.

9. An energy storage system, characterized in that: include: At least one battery system and a power converter as claimed in claim 8.

10. The energy storage system according to claim 9, characterized in that: The power converter is an inverter, and the second side of the main circuit in the power converter is connected to a photovoltaic device.

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