Power distribution method, system controller, battery pack energy storage system and medium

Abstract

The present application discloses a power distribution method, a system controller, a battery pack energy storage system and a medium, the method comprising: obtaining the current state of charge SOC value of each group of operating battery cells in a plurality of groups of operating battery cells and the target compensation power determined according to the voltage change value of the power grid; determining the output power required for each group of operating battery cells based on the current state of charge SOC value of the operating battery cells, the target compensation power and preset rules; determining the output ratio of each group of operating battery cells according to the output power required for each group of operating battery cells and the target compensation power; and sending the output ratio to the operating battery cells corresponding to the output ratio. This technical solution can determine the output ratio of the operating battery cells by combining the SOC value with the power equalization, thereby improving the consistency of the operating battery cells in the system after use, effectively preventing the operating battery cells of each branch from having excessive differences in state, and further improving the reliability and stability of the system operation.

Description

Technical Field

[0001] The present invention generally relates to the technical field of energy storage system control, and specifically relates to a power distribution method, a system controller, a battery pack energy storage system and a medium. Background Art

[0002] With the rapid development of power electronics and new energy technologies, energy storage systems and electric vehicle lithium battery packs mostly use multi-branch battery packs in parallel. As the system scale continues to increase, the number of parallel battery packs is also increasing. The battery packs connected in parallel will have current imbalance due to differences in battery voltage, internal resistance, self-discharge rate and other parameters. For example, current circulation will occur between branches, thus affecting the life of the energy storage system. In addition, when charging the parallel battery packs, the charging amount of each branch will be different, thus creating safety hazards.

[0003] At present, in the prior art, switches are connected in series on branch battery packs to realize sequential charging of parallel battery packs to avoid circulating currents between battery packs. However, this solution cannot simultaneously charge battery packs with multiple branches connected in parallel and suppress circulating currents. Balancing resistors can also be used to control the balanced currents of parallel branches. However, the balancing resistors used are lossy devices that consume energy of the system. Although the smaller the balancing resistor, the better, a balancing resistor that is too small cannot achieve the purpose of balancing branch currents, and a balancing resistor that is too large will cause energy waste. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a power distribution method, a system controller, a battery pack energy storage system and a medium.

[0005] In a first aspect, the present application provides a method for allocating power to multiple groups of operating battery units, the method comprising:

[0006] Obtaining a current state of charge (SOC) value of each group of operating battery cells in a plurality of groups of operating battery cells and a target compensation power determined according to a voltage change value of a power grid;

[0007] Determine the output power required for each group of operating battery cells based on the current state of charge SOC value of the operating battery cells, the target compensation power and preset rules;

[0008] Determine the output ratio of each group of operating battery cells according to the output power required by each group of operating battery cells and the target compensation power;

[0009] The output ratio is sent to the operating battery unit corresponding to the output ratio.

[0010] In one embodiment, the preset rules include:

[0011] determining a type of output power required to operate the battery unit based on the target compensation power;

[0012] According to the output power type, the SOC value of each group of operating battery cells and the target compensation power, the output power corresponding to the output power type of each group of operating battery cells is determined.

[0013] In one embodiment, determining the output ratio of each group of operating battery cells according to the output power required by each group of operating battery cells includes:

[0014] Determine the average power based on the target compensation power and the number of operating battery units;

[0015] respectively determining a sum and a difference between the average power and a preset threshold;

[0016] Based on the sum value, the difference value and the output power required by each group of operating battery units, determine the actual output power and unallocated power of each group of operating battery units, and set a power allocation completion flag;

[0017] Based on the actual output power and the target compensation power, the output ratio of each group of operating battery units is determined.

[0018] In one embodiment, based on the sum value, the difference value and the output power required by each group of operating battery units, determining the actual output power and the unallocated power of each group of operating battery units, and setting a power allocation completion flag, includes:

[0019] When the output power required by the operating battery unit is greater than the sum value, the actual output power is determined to be the sum value, and the output power required by the operating battery unit is calculated by subtracting the sum value to obtain the unallocated power, and a power allocation completion mark is set for the operating battery unit whose output power is greater than the sum value;

[0020] When the output power required for the running battery unit is less than the difference, the actual output power is determined to be the difference, and the output power required for the running battery unit is calculated by subtracting the difference from the difference to obtain the unallocated power, and a power allocation completion mark is set for the running battery unit whose output power is less than the difference;

[0021] When the output power required for operating the battery unit is greater than or equal to the difference value and less than or equal to the sum value, it is determined that the unallocated power of the operating battery unit is zero.

[0022] In one embodiment, after determining the actual output power and unallocated power of each group of operating battery cells based on the sum value, the difference value and the output power required by each group of operating battery cells, and setting a power allocation completion flag, the method further includes:

[0023] determining the sum of the unallocated powers of all operating battery units;

[0024] Determine the operating battery unit for which the power allocation completion mark is not set;

[0025] For the operating battery unit whose power allocation completion flag is not set, the actual output power is determined based on the SOC value and the sum of the unallocated power, and the power allocation completion flag is set.

[0026] In one embodiment, for a running battery unit that has not set a power allocation completion flag, determining the actual output power based on the SOC value and the sum of the unallocated power includes:

[0027] Determine the actual output power type of the operating battery unit that has not set the power allocation completion mark;

[0028] The actual output power of the operating battery unit without a power allocation completion flag is determined based on the output power required by the operating battery unit without a power allocation completion flag, the SOC values ​​of all operating battery units, and the sum of unallocated powers.

[0029] In one embodiment, based on the current state of charge SOC value of the operating battery unit, the target compensation power and the preset rule, the output power required by each group of operating battery units is determined, including:

[0030] Determine the average power based on the target compensation power and the number of operating battery units;

[0031] Determining an average SOC value based on the SOC values ​​of the operating battery cells and the number of operating battery cells;

[0032] Based on the target compensation power, determine the output power type required for each group of operating battery units;

[0033] The output power corresponding to the output power type required by each group of operating battery cells is determined according to the output power type, the average SOC value, the average power and the SOC value of each group of operating battery cells.

[0034] In one embodiment, according to the output power required by each group of operating battery cells and the target compensation power, the output ratio of each group of operating battery cells is determined, including:

[0035] respectively determining a sum and a difference between the average power and a preset threshold;

[0036] Based on the sum value, the difference value and the output power required by each group of operating battery units, determine the actual output power of each group of operating battery units, and set a power allocation completion flag;

[0037] Based on the actual output power and the target compensation power, the output ratio of each group of operating battery units is determined.

[0038] In one embodiment, based on the sum value, the difference value and the output power required by each group of operating battery cells, determining the actual output power of each group of operating battery cells and setting a power allocation completion flag includes:

[0039] When the output power required by the operating battery unit is greater than the sum value, determining the actual output power to be the sum value, and setting a power allocation completion mark for the operating battery unit whose required output power is greater than the sum value;

[0040] When the output power required for the operating battery unit is less than the difference, determining the actual output power to be the difference, and setting a power allocation completion flag for the operating battery unit whose required output power is less than the difference;

[0041] When the output power required to operate the battery unit is greater than or equal to the difference value and less than or equal to the sum value, determining the first actual output power as the required output power;

[0042] In one embodiment, after determining the actual output power of each group of operating battery cells based on the sum value, the difference value and the output power required by each group of operating battery cells and setting the power allocation completion mark, the method further includes:

[0043] Determine the sum of unallocated powers of all operating battery units based on the target compensation power and the actual output power;

[0044] Determine the operating battery unit for which the power allocation completion mark is not set;

[0045] Determine an average value of the unallocated power based on the total unallocated power and the number of operating battery units;

[0046] For the operating battery unit for which the power allocation completion mark is not set, determining the second actual output power based on the unallocated power average value and the average SOC value;

[0047] Based on the first actual output power and the second actual output power, the actual output power of the operating battery unit for which the power allocation completion flag is not set is determined, and the power allocation completion flag is set.

[0048] In one embodiment, before obtaining the current state of charge SOC value of each group of operating battery cells in the plurality of groups of operating battery cells and the target compensation power determined according to the voltage change value of the power grid, the method further includes:

[0049] Before each group of operating battery cells operates normally, a pre-charging process is performed on each group of battery cells to be operated to obtain a pre-charging result;

[0050] When the pre-charging result indicates that the pre-charging is successful, each group of battery cells to be operated is determined to be an operating battery cell.

[0051] In a second aspect, the present application provides a system controller, including a memory, a processor, and a determination program stored in the memory and executable on the processor, wherein when the processor executes the program, the power allocation method described in the embodiment of the present application is implemented.

[0052] In a third aspect, the present application provides a computer-readable storage medium having a determination machine program stored thereon, which is used to implement the power allocation method described in the embodiments of the present application when executed by a processor.

[0053] In a fourth aspect, the present application provides a battery energy storage system, the system comprising a combiner cabinet unit and a plurality of parallel-connected operating battery units, the combiner cabinet unit comprising a system controller, the system controller is respectively connected to each operating battery unit in the plurality of parallel-connected operating battery units, and the system controller is connected to a power grid;

[0054] The system controller is used to receive the voltage change value of the power grid and determine the target compensation power according to the voltage change value of the power grid;

[0055] The system controller is also used to obtain the current state of charge SOC value of each group of operating battery cells in the multiple groups of operating battery cells; determine the output power required by each group of operating battery cells according to the current state of charge SOC value of the group of operating battery cells, the target compensation power and the preset rules; determine the output ratio of each group of operating battery cells according to the output power required by each group of operating battery cells and the target compensation power; and send the output ratio to the operating battery cells corresponding to the output ratio;

[0056] The operating battery unit is used to output corresponding power according to the received output ratio.

[0057] The power distribution method, system controller, battery pack energy storage system and medium provided in the embodiment of the present application obtain the current state of charge SOC value of each group of operating battery cells in multiple groups of operating battery cells and the target compensation power determined according to the change value of the grid voltage, and determine the output power required for each group of operating battery cells based on the current state of charge SOC value of the operating battery cells, the target compensation power and preset rules, and determine the output ratio of each group of operating battery cells according to the output power required for each group of operating battery cells and the target compensation power, and send the output ratio to the operating battery cells corresponding to the output ratio. This technical solution determines the output ratio of the operating battery cells by combining the SOC value with the power averaging, thereby improving the consistency of the operating battery cells in the system after use, effectively preventing the operating battery cells of each branch from having too large a difference in state, and further improving the reliability and stability of the system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0059] Figure 1 A schematic diagram of the structure of a battery pack energy storage system provided in an embodiment of the present application;

[0060] Figure 2 A schematic diagram of the structure of a battery pack energy storage system provided in an embodiment of the present application;

[0061] Figure 3 A schematic diagram of the structure of a battery pack energy storage system provided in an embodiment of the present application;

[0062] Figure 4 A schematic diagram of a power allocation method according to an embodiment of the present invention;

[0063] Figure 5 A schematic diagram of a power allocation method according to an embodiment of the present invention;

[0064] Figure 6 A schematic diagram of a power allocation method according to an embodiment of the present invention;

[0065] Description of reference numerals:

[0066] 10- combiner cabinet unit; 20- running battery unit; 30- communication unit; 40- front-end switch cabinet; 50- fire controller; 101- system controller; 102- branch contactor; 103- pre-charge resistor; 104- branch pre-charge contactor; 201- DCDC unit; 202- battery management unit. DETAILED DESCRIPTION

[0067] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0068] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0069] It can be understood that in a multi-branch energy storage system, each branch is provided with a corresponding power battery, and multiple branches can be charged and discharged, and balanced distribution management is required during the charging or discharging process.

[0070] At present, in the related technology, there is a method of sequentially charging parallel battery groups by connecting switches in series on the branch battery groups, thereby avoiding circulating currents between battery groups. However, the series switches on the branch battery groups cannot simultaneously charge the battery groups connected in parallel with multiple branches and circulate currents in unison. It is also possible to use a balancing resistor to control the balancing current of the parallel branches, but the balancing ability of the balancing resistor is limited, and the balancing resistor used is a loss-type device that consumes the energy of the system. Although the smaller the balancing resistor, the better, a balancing resistor that is too small may not be able to achieve the purpose of balancing the branch current, and a balancing resistor that is too large will cause energy waste. It is also possible to use a method of balancing the battery output power. However, due to the individual differences of each battery group, long-term balancing of power leads to inconsistent battery status, which affects the life and performance of the energy storage system. There may also be a situation where a branch is full while other branches are not full, creating a safety hazard. In addition, it is also possible to use a method based on the battery state of charge (State When the SOC of each battery group in the system is slightly different, the output power of each battery group is slightly different. However, when the SOC of each battery group in the system is significantly different, each branch will have uneven current flow, resulting in circulating current in the system.

[0071] Based on the above-mentioned defects, the present application provides a power distribution method, a system controller, a battery pack energy storage system and a medium, which can determine the output ratio of the operating battery cells by combining the SOC value with the power balancing, thereby improving the consistency of the operating battery cells in the system after use, effectively preventing the operating battery cells of each branch from having excessive differences in state, and further improving the reliability and stability of the system operation.

[0072] The power allocation method provided in the embodiment of the present application can be applied to Figure 1 The battery energy storage system shown.

[0073] like Figure 1 As shown, the battery energy storage system includes: a combiner cabinet unit 10 and multiple groups of parallel operating battery units 20. The combiner cabinet unit 10 includes a system controller 101. The system controller 101 is respectively connected to each group of operating battery units 20 in the multiple groups of parallel operating battery units, and the system controller 101 is connected to the power grid.

[0074] The system controller 101 is used to receive the voltage change value of the power grid and determine the target compensation power according to the voltage change value of the power grid. Optionally, the power grid may be a track power grid arranged on a track.

[0075] The system controller 101 is also used to obtain the current state of charge SOC value of each group of operating battery cells 20 in the multiple groups of operating battery cells; determine the output power required for each group of operating battery cells 20 according to the current state of charge SOC value and the target compensation power of each group of operating battery cells, and determine the output ratio of each group of operating battery cells 20 according to the output power required for each group of operating battery cells 20 and the target compensation power, and send the output ratio to the operating battery cells 20 corresponding to the output ratio.

[0076] Among them, see Figure 2 As shown, the system controller 101 is connected to each group of operating battery cells 20 through the first branch or the second branch; when the first branch is in an open state and the second branch is in a closed state, the system controller 101 is connected to the battery cells through the second branch, and the second branch is used to perform pre-charging processing on each group of battery cells to be operated to obtain a pre-charging result, and send the pre-charging result fed back by each group of battery cells to be operated to the system controller, and the system controller 101 is used to determine whether the battery cells to be operated are operating battery cells according to the pre-charging results.

[0077] When the first branch is in a closed state and the second branch is in an open state, the system controller 101 is connected to each group of operating battery units through the first branch, and the first branch is used for data transmission between the system controller and each group of operating battery units.

[0078] The first branch includes a branch contactor 102, which is used to perform on or off according to the control instruction sent by the system controller 101, and the second branch includes a pre-charging resistor 103 and a branch pre-charging contactor 104 connected in series with the pre-charging resistor 103, and the branch pre-charging contactor 104 is used to perform on or off according to the control instruction sent by the system controller 101. The pre-charging resistor 103 is used to prevent the charging current from being too large to break down the electrical components. The purpose of pre-charging the battery unit to be operated is to prevent the direct closing of the branch contactor from generating an impact current.

[0079] Optionally, the operating battery unit 20 may include a DCDC unit 201 and a battery management unit 202 (Battery Management System, BMS) controller, the DCDC unit 201 is used to control the operating battery unit to output corresponding power according to the received output ratio and target compensation power; the battery management unit 202 is used to detect battery status information and send the battery status information to the system controller 101, and the battery status information may be, for example, the current state of charge SOC value of the operating battery unit 20.

[0080] like Figure 3As shown, the system may further include a communication unit 30, a front switch cabinet 40 and a fire controller 50. The communication unit 30 is connected to the operating battery unit 20 and the combiner cabinet unit 10 respectively, and the combiner cabinet unit 10 is connected to the front switch cabinet 40 and the fire controller 50 respectively.

[0081] The communication unit 30 is used for the battery energy storage system to communicate with the outside through wired communication equipment and wireless communication. The wireless communication can be realized through wireless communication equipment, wherein the wireless communication equipment can be wireless AP, wireless bridge, wireless network card, wireless lightning rod, antenna and other equipment. The front switch cabinet 40 is used to connect the junction cabinet unit 10 with the track, mainly to open and close, control and protect the electrical equipment in the process of power generation, transmission, distribution and power conversion of the power system. The front switch cabinet can include circuit breakers, isolating switches, load switches and various protection devices.

[0082] When the system controller 101 detects a safety hazard such as a fault, a trip signal is sent to the front switch cabinet 40 through a passive dry contact, so that the front switch cabinet 40 disconnects the system from the track after receiving the trip signal, thereby protecting the system.

[0083] Among them, the junction cabinet unit 40 may include an isolating switch. When the isolating switch in the junction cabinet unit 40 is closed and the circuit breaker in the front-end switch cabinet is closed, the front-end switch cabinet 40 sends an interlocking signal to the junction cabinet unit 10 to prompt the operator to stop operating the isolating switch in the junction cabinet unit 10, so as to avoid the isolating switch in the junction cabinet unit from being damaged due to load operation.

[0084] The combiner cabinet unit 40 may send a circuit breaker closing permission signal to the front-end switch cabinet 40 through a passive dry contact, so that the front-end switch cabinet 40 is allowed to open the circuit breaker.

[0085] The fire controller 50 is used to detect whether there are dangerous signals in the system. When dangerous signals such as smoke are detected, a fire linkage signal is sent to the system controller 101 in the junction box unit 10, so that the system controller 101 controls the system to stop working.

[0086] The system controller 101 can send a start / stop signal to the operating battery unit 20 through a passive dry contact to start or stop the operating battery unit. It can also receive a status feedback signal sent by the operating battery unit 20 through a passive dry contact. The status feedback signal can be a signal detected by the operating battery unit 20 to determine whether the battery itself has a fault.

[0087] The battery pack energy storage system provided in this application can be used with the track for charging and discharging the track. Compared with the general energy storage system, it has a high voltage level, high instantaneous output power, fast response rate, and has higher requirements on the state and consistency of the battery SOC.

[0088] Furthermore, the operating battery cells in the battery pack energy storage system provided in the present application are independent of each other, and their connection or disconnection can be controlled by branch contactors. When any operating battery cell fails, it will not affect the normal operation of the system. The multi-branch energy storage system can use Ethernet or a dry contact system for communication. This communication method has strong anti-interference ability and greatly improves the system reliability.

[0089] For ease of understanding and explanation, the following Figures 4 to 6 The power allocation method provided in the embodiment of the present application is described in detail.

[0090] like Figure 4 As shown, Figure 4 A schematic diagram of a power distribution method for multiple groups of operating battery cells provided in an embodiment of the present application. The method is applied to a battery energy storage system, which can be implemented as part or all of a battery energy storage system through software, hardware, or a combination of software and hardware. Figure 4 As shown, the method includes:

[0091] S101, obtaining a current state of charge (SOC) value of each group of operating battery cells in a plurality of groups of operating battery cells and a target compensation power determined according to a voltage change value of a power grid.

[0092] Specifically, the system controller can communicate with each battery unit in turn and establish a connection with a dry contact signal to determine whether the battery unit has a fault. When it is determined that the battery unit has a fault, it is determined that the battery unit is abnormal, and the battery unit is no longer connected to the system controller; when it is determined that the battery unit has no fault, it can be determined that the battery unit is a battery unit to be operated. Optionally, there can be multiple battery units to be operated.

[0093] The communication method can be CAN communication, RS485 communication or other equivalent communication methods. A dry contact is an electrical switch having two signal states: closed and open.

[0094] After determining the normal battery cell, the system controller can send a start control instruction to the battery cell to be operated, so that the branch pre-charging contactor performs a connection operation according to the control instruction sent by the system controller, that is, closes the branch pre-charging contactor, and forms a second branch with the battery cell to be operated through the pre-charging resistor, performs pre-charging processing on the battery cell to be operated in turn, obtains the pre-charging result, and determines the battery cell to be operated whose pre-charging result indicates that the pre-charging is successful as the operating battery cell, and disconnects the branch pre-charging contactor. The system controller sends a control instruction to the branch contactor, so that the branch contactor performs a connection operation according to the control instruction sent by the system controller, that is, closes the branch contactor, and forms a first branch with the operating battery cell; when the pre-charging result indicates that the pre-charging fails, continues to pre-charge the battery cell to be operated for a preset number of times, and the preset number of times can be three times. When the pre-charging failure still occurs after polling the preset number of times, it is determined that the battery cell to be operated is abnormal, and the battery cell to be operated is no longer connected to the first branch. The voltage at both ends of the branch pre-charging contactor can be sampled, and when the voltage difference between the two ends is within a preset range, it is determined that the voltage unit to be operated is pre-charged successfully. The preset range can be 0 to 15V.

[0095] The BMS obtains the SOC value of each group of operating battery cells in the multiple groups of operating battery cells, and sends the SOC value of each group of operating battery cells to the system controller, so that the system controller obtains the SOC value of each group of operating battery cells.

[0096] It should be noted that the state of charge (SOC) indicates the remaining power of an energy pack such as a battery. The SOC is usually expressed as the ratio of the remaining power of the battery to its capacity when it is fully charged, for example, as a percentage, with a value range of 0-1; when SOC=0, it means that the battery is fully discharged, and when SOC=1, it means that the battery is fully charged.

[0097] Optionally, the junction box unit may include a sampling unit, which detects the voltage change value of the grid voltage at the output end in real time through the sampling unit and sends it to the system controller, so that the system controller obtains the voltage change value of the grid, thereby obtaining the target compensation power required to stabilize the grid voltage fluctuation. The target compensation power is the total power required to output to maintain the stability of the system grid.

[0098] S102 : Determine the output power corresponding to the output power type of each group of operating battery cells based on the current state of charge SOC value of the operating battery cells, the target compensation power and a preset rule.

[0099] In this step, the preset rules may include: for each group of operating battery cells in the plurality of groups of operating battery cells, the output power type required by each group of operating battery cells may be determined based on the target compensation power, and the output power corresponding to the output power type of each group of operating battery cells may be determined according to the output power type, the SOC value of each group of operating battery cells and the target compensation power. The output power type includes charging output power and discharging output power.

[0100] When the target compensation power is less than zero, the output power type required to operate the battery unit is determined to be charging output power. When the target compensation power is greater than or equal to zero, the output power type required to operate the battery unit is determined to be discharging output power, that is:

[0101] If P 总 <0, then P′ i =P′ i充电 ; Otherwise, P′ i =P′ i放电 .

[0102] Among them, P 总 is the target compensation power, P' i The output power required to operate the battery cell for i#.

[0103] When it is determined that the output power type is discharge output power, the discharge output power of the operating battery unit can be determined by the following formula according to the SOC value of each group of operating battery units and the target compensation power:

[0104]

[0105] When it is determined that the output power type is charging output power, the charging output power of the operating battery unit can be determined by the SOC value of each group of operating battery units and the target compensation power through the following formula:

[0106]

[0107] Among them, SOC i is the SOC value of the i# operating battery cell, P 总 Compensation power for target, SOC 1 …SOC n is the SOC value of the i (i=1...n)# operating battery cell, P′ i充电 is the charging output power of the i# operating battery cell, P′ i放电 is the discharge output power of the i# operating battery cell.

[0108] Optionally, as an implementable manner, when determining the output power corresponding to the output power type of each group of operating battery cells, the average power may be determined based on the target compensation power and the number of operating battery cells, and the average SOC value may be determined based on the SOC value of the operating battery cells and the number of operating battery cells. The average SOC value and the average power may be determined by the following formula:

[0109]

[0110]

[0111] Among them, P 总 is the target compensation power, n is the number of operating battery cells, SOC i is the SOC value of the i# operating battery cell, P 平 is the average power of all operating battery cells, SOC 平 is the average SOC value of all operating battery cells.

[0112] After determining the average power and the average SOC value, the output power type required for each group of operating battery cells can be determined based on the target compensation power, and the output power corresponding to the output power type required for each group of operating battery cells can be determined based on the output power type, the average SOC value, the average power and the SOC value of each group of operating battery cells. The output power type can be either a discharge output power or a charging output power. When the target compensation power is less than zero, the output power type required for the operating battery cell is determined to be the charging output power, and when the target compensation power is greater than or equal to zero, the output power type required for the operating battery cell is determined to be the discharging output power.

[0113] When it is determined that the output power type is discharge output power, the discharge output power of the operating battery unit is determined by the following formula:

[0114]

[0115] When it is determined that the output power type is charging output power, the charging output power of the operating battery unit is determined by the following formula:

[0116]

[0117] Among them, SOC i is the SOC value of the i# operating battery cell, P 平 is the average power of all operating battery cells, SOC 平 is the average SOC value of all operating battery cells, P′ i充电 is the charging output power of the i# operating battery cell, P′ i放电is the discharge output power of the i# operating battery cell.

[0118] S103 , determining the output ratio of each group of operating battery units according to the output power required by each group of operating battery units and the target compensation power.

[0119] S104: Send the output ratio to the operating battery unit corresponding to the output ratio.

[0120] Specifically, after determining the output power required for each group of operating battery cells, the actual output power can be determined based on the output power required for each group of operating battery cells, and the output ratio of each group of operating battery cells can be determined based on the actual output power and the target compensation power.

[0121] Optionally, the system controller can send the output ratio to the operating battery unit corresponding to the output ratio. This solution enables the operating battery unit to determine the total compensation power by sampling the bus voltage change value on the output side after receiving the output ratio, and output the corresponding power according to the output ratio and the total compensation power, thereby improving the consistency of the operating battery unit in the system after use, and effectively preventing the operating battery unit status of each branch from being too different.

[0122] Optionally, the system controller may also send the output ratio and the target compensation power to the operating battery unit corresponding to the output ratio. This technical solution can avoid the situation where the operating battery unit cannot determine whether the target compensation power is normal only by the sent output ratio when communication abnormality occurs between the system controller and the operating battery unit. The operating battery unit can obtain the total compensation power by sampling the bus voltage change value on the output side through the detection unit, so as to further determine whether the deviation between the total compensation power and the target compensation power sent by the system controller is within the allowable range. If the deviation is within the allowable range, the operating battery unit determines and outputs the corresponding power according to the output ratio and the target compensation power, otherwise the operating battery unit stops outputting power, thereby ensuring the reliability and safety of the system and saving the detection time of communication failures.

[0123] Based on the above embodiments, Figure 5 As shown, the above S103 may include the following method steps:

[0124] S201 . Determine average power based on target compensation power and the number of operating battery units.

[0125] S202: Determine the sum and difference between the average power and a preset threshold value respectively.

[0126] In this step, the average power of all operating battery cells may be determined, and the sum of the average power and a preset threshold may be determined as a sum value, and the difference between the average power and the preset threshold may be determined as a difference value.

[0127] S203: Based on the sum, the difference and the output power required by each group of operating battery units, determine the actual output power and the unallocated power of each group of operating battery units, and set a power allocation completion mark.

[0128] Specifically, when the output power required for the operating battery cell is greater than the sum value, the actual output power of the operating battery cell is determined to be the sum value, and the output power required for the operating battery cell is subtracted from the sum value to determine the unallocated power, and a power allocation completion mark is set for the operating battery cell whose output power is greater than the sum value.

[0129] When the output power required for the operating battery cell is less than the difference, the actual output power of the operating battery cell is determined to be the difference, and the output power required for the operating battery cell is subtracted from the difference to determine the unallocated power, and a power allocation completion mark is set for the operating battery cell whose output power is less than the difference.

[0130] When the output power required by the operating battery unit is greater than or equal to the difference and less than or equal to the sum, the unallocated power of the operating battery unit is determined to be zero, and the power allocation completion mark is not set for the operating battery unit whose output power is greater than or equal to the difference and less than or equal to the sum.

[0131] The above judgment process can be expressed by the following formula:

[0132] If P′ i >P 平均 +P 限 , then P i =P 平均 +P 限 , set the i# running battery unit as the power allocation mark, and the unallocated power of the running battery unit is:

[0133] P i未分配 =P′ i -P i ;

[0134] If P′ i <P 平均 -P 限 , then P i =P 平均 -P 限 , set the i# running battery unit as the power allocation completion mark, and the unallocated power of the running battery unit is:

[0135] P i未分配 =P′i -P i ;

[0136] If P 平均 -P 限 ≤P′ i ≤P 平均 +P 限 , then the i# running battery unit is waiting for power distribution, that is, P i未分配 =0.

[0137] Among them, P 平均 is the average power of all operating battery cells, P 限 is the preset threshold, P i未分配 is the unallocated power of the i# operating battery cell, P' i is the output power required to operate the battery cell #i, P i The actual output power of the operating battery cell #i.

[0138] For the running battery cells that have not set the power allocation completion mark, the total unallocated power of all running battery cells can be determined, and the running battery cells that have not set the power allocation completion mark can be determined. For the running battery cells that have not set the power allocation completion mark, the actual output power is determined based on the SOC value and the total unallocated power, and the power allocation completion mark is set.

[0139] The total unallocated power can be determined by the following formula:

[0140]

[0141] Among them, P 未分配 is the sum of the unallocated power of all operating battery units, P i未分配 The unallocated power of the i# operating battery unit.

[0142] If the sum of the unallocated power is not zero, when determining and setting the actual output power of the power allocation completion mark based on the SOC value and the sum of the unallocated power, the actual output power type of the operating battery unit for which the power allocation completion mark is not set can be determined first, and the actual output power type can include the actual discharge output power and the actual charging output power, and based on the output power required by the operating battery unit for which the power allocation completion mark is not set, the SOC value of all the operating battery units, and the sum of the unallocated power, the actual output power of the operating battery unit for which the power allocation completion mark is not set is determined, and the actual output power of the operating battery unit for which the power allocation completion mark is not set can be determined by the following formula, and the power allocation completion mark is set:

[0143]

[0144]

[0145] Among them, P 未分配 is the sum of the unallocated power of all operating battery cells, P' i The output power required for the i# operating battery cell without power completion mark, SOC j The SOC value corresponding to the j# operating battery cell that has not been marked as power completed.

[0146] If the sum of the unallocated power is zero, the power completion flag is set for all the operating battery units, and the actual output power of the operating battery units without the power allocation completion flag is determined by the following formula:

[0147] P i =P′ i

[0148] Among them, P′ i The output power required by the i# operating battery unit whose power allocation completion flag is not set, P i The actual output power of the i# operating battery unit whose power allocation completion flag is not set.

[0149] Optionally, as another possible implementation method, based on the above embodiment, see Figure 6 As shown, the above step S103 may also include the following method steps:

[0150] S301 : respectively determine a sum and a difference between an average power and a preset threshold.

[0151] S302: Based on the sum value, the difference value and the output power required by each group of operating battery units, determine the actual output power of each group of operating battery units, and set a power allocation completion mark.

[0152] S303 : Determine the output ratio of each group of operating battery units based on the actual output power and the target compensation power.

[0153] Specifically, after respectively determining the sum and difference of the average power and the preset threshold, the actual output power of each group of operating battery cells can be determined based on the sum, the difference and the output power required by each group of operating battery cells, and a power allocation completion mark can be set. When the output power required by the operating battery cell is greater than the sum, the actual output power of the operating battery cell is determined to be the sum, and a power allocation completion mark is set for the operating battery cell whose required output power is greater than the sum; when the output power required by the operating battery cell is less than the difference, the actual output power of the operating battery cell is determined to be the difference, and a power allocation completion mark is set for the operating battery cell whose required output power is less than the difference; when the output power required by the operating battery cell is greater than or equal to the difference and less than or equal to the sum, the first actual output power of the operating battery cell is determined to be the required output power. Among them, the first actual output power is part of the actual output power of the operating battery cell.

[0154] The above process can be expressed by the following formula:

[0155] If P′ i >P 平均 +P 限 , then P i =P 平均 +P 限 , set i# running battery unit as power allocation mark;

[0156] If P′ i <P 平均 -P 限 , then P i =P 平均 -P 限 , set the i# running battery unit to the power allocation completion mark;

[0157] If P 平均 -P 限 ≤P′ i ≤P 平均 +P 限 , then the i# running battery unit is waiting for power distribution, P 1 =P′ i ;

[0158] Among them, P 平均 is the average power of all operating battery cells, P 限 is the preset threshold, P 未分配 is the sum of the unallocated power of all operating battery cells, P' i is the output power required to operate the battery cell #i, P i is the actual output power of the battery unit in operation #i, P 总 is the target compensation power, and N is the number of operating battery units.1 The first actual output power of the i# operating battery cell.

[0159] Then, based on the target compensation power, the actual output power and the first actual output power, the total unallocated power of all operating battery cells is determined, and the operating battery cells for which the power allocation completion mark is not set are determined, that is, the operating battery cells for which the required output power is greater than or equal to the difference and less than or equal to the sum value. Then, for the operating battery cells for which the power allocation completion mark is not set, the second actual output power is determined based on the average unallocated power value and the average SOC value, and based on the first actual output power and the second actual output power, the actual output power of the operating battery cells for which the power allocation completion mark is not set is determined, and the power allocation completion mark is set.

[0160] The sum of the unallocated power of all operating battery cells can be determined by the following formula:

[0161]

[0162] Among them, P 未分配 is the sum of the unallocated power of all operating battery units, P i is the actual output power of the i# operating battery unit, N is the number of operating battery units, P 总 is the target compensation power, p 1 The first actual output power of the i# operating battery cell.

[0163] When the sum of the unallocated powers of the operating battery cells is not zero, the second actual output power of the operating battery cells without the power completion mark is determined, and the first actual output power and the second actual output power are added to obtain the actual output power of the operating battery cells without the power allocation completion mark, and the power allocation completion mark is set. The above process can, for example, first determine the unallocated power average value and the average SOC value by the following formula:

[0164]

[0165]

[0166] When it is determined that the actual output power type is the actual charging output power, the second actual output power of the operating battery unit is determined to be:

[0167]

[0168] When it is determined that the actual output power type is the actual discharging output power, the second actual output power of the operating battery unit is determined to be:

[0169]

[0170] After determining the first actual output power and the second actual output power, the actual output power of the operating battery unit without a power allocation completion mark is calculated by the following formula:

[0171] p i =p 1 +p 2

[0172] Among them, P 未分配 is the sum of the unallocated powers of all operating battery cells, p′ 未分配平 is the average unallocated power of all operating battery cells, SOC 平 is the average SOC value of all running battery cells, SOC i is the SOC value of the i# operating battery cell, n is the number of operating battery cells, p 1 is the first actual output power of the operating battery unit #i, p 2 is the second actual output power of the i# operating battery cell.

[0173] S204: Determine the output ratio of each group of operating battery units based on the actual output power and the target compensation power.

[0174] After obtaining the actual output power of all operating battery units, the ratio of the actual output power to the target compensation power can be determined, such as by the following formula:

[0175]

[0176] Among them, α i is the output ratio of the i# operating battery cell, P i is the actual output power of the battery cell running for i#, P 总 Compensate power for the target.

[0177] After receiving the output ratio and the target compensation power, each group of operating battery units outputs corresponding power according to the output ratio and the target compensation power.

[0178] The power allocation method provided in the embodiment of the present application determines the output ratio of the operating battery cells by combining the SOC value with the power balancing method. Compared with the power balancing method used alone in the related art, it improves the consistency of the operating battery cells in the system after use, and effectively prevents excessive differences in the states of the operating battery cells in each branch. Compared with the method of allocating power using the SOC value alone in the related art, it avoids the circulation caused by excessive differences in the allocated power in the system, thereby improving the reliability and stability of the system operation.

[0179] It should be noted that although the operations of the method of the present invention are described in a particular order in the accompanying drawings, this does not require or imply that the operations must be performed in this particular order, or that all the operations shown must be performed to achieve the desired results. On the contrary, the steps depicted in the flow chart can be performed in a different order. Additionally or alternatively, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps.

[0180] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A method for distributing power among multiple groups of operating battery units, characterized in that: include: Obtaining a current state of charge (SOC) value of each group of operating battery cells in a plurality of groups of operating battery cells and a target compensation power determined according to a voltage change value of a power grid; Determine the output power required for each group of the operating battery cells based on the current state of charge SOC value of the operating battery cells, the target compensation power and a preset rule; Determining an output ratio of each group of the operating battery units according to the output power required by each group of the operating battery units and the target compensation power; sending the output ratio to the operating battery unit corresponding to the output ratio; The step of determining the output ratio of each group of operating battery cells according to the output power required by each group of operating battery cells and the target compensation power comprises: Determining average power based on the target compensation power and the number of operating battery units; Determine the sum and difference between the average power and a preset threshold value respectively; Based on the sum, the difference and the output power required by each group of the operating battery units, determine the actual output power of each group of the operating battery units, and set a power allocation completion mark; Based on the actual output power and the target compensation power, an output ratio of each group of operating battery units is determined.

2. The method according to claim 1, characterized in that The preset rules include: Based on the target compensation power, determining the output power type required for each group of the operating battery units; The output power corresponding to the output power type required by each group of operating battery cells is determined according to the output power type, the SOC value of each group of operating battery cells and the target compensation power.

3. The method according to claim 1, characterized in that The determining the actual output power of each group of the operating battery units based on the sum, the difference and the output power required by each group of the operating battery units comprises: Based on the sum, the difference and the output power required by each group of the operating battery units, the actual output power and the unallocated power of each group of the operating battery units are determined.

4. The method according to claim 3, characterized in that Based on the sum, the difference and the output power required by each group of the operating battery units, determining the actual output power and the unallocated power of each group of the operating battery units, and setting a power allocation completion mark, including: When the output power required by the operating battery unit is greater than the sum value, determining that the actual output power is the sum value, and calculating the difference between the output power required by the operating battery unit and the sum value to obtain the unallocated power, and setting a power allocation completion mark for the operating battery unit whose required output power is greater than the sum value; When the output power required by the operating battery unit is less than the difference, determining that the actual output power is the difference, and calculating the difference between the output power required by the operating battery unit and the difference to obtain the unallocated power, and setting a power allocation completion mark for the operating battery unit whose required output power is less than the difference; When the output power required by the operating battery unit is greater than or equal to the difference and less than or equal to the sum, it is determined that the unallocated power of the operating battery unit is zero.

5. The method according to claim 4, characterized in that After determining the actual output power and the unallocated power of each group of the operating battery units based on the sum, the difference and the output power required by each group of the operating battery units, and setting a power allocation completion mark, the method further includes: determining the sum of the unallocated powers of all operating battery units; Determine the operating battery unit for which the power allocation completion mark is not set; For the operating battery unit for which the power allocation completion flag is not set, the actual output power is determined based on the SOC value and the sum of the unallocated power, and the power allocation completion flag is set.

6. The method according to claim 5, characterized in that For the operating battery unit for which the power allocation completion mark is not set, determining the actual output power based on the SOC value and the sum of the unallocated power includes: Determine the actual output power type of the operating battery unit for which the power allocation completion mark is not set; The actual output power of the operating battery unit without a power allocation completion flag is determined based on the output power required by the operating battery unit without a power allocation completion flag, the SOC values ​​of all operating battery units and the sum of the unallocated powers.

7. The method according to claim 1, characterized in that Determining the output power required by each group of the operating battery cells based on the current state of charge SOC value of the operating battery cells, the target compensation power and a preset rule, including: Determining average power based on the target compensation power and the number of operating battery units; Determining an average SOC value based on the SOC value of the operating battery cell and the number of operating battery cells; Based on the target compensation power, determining the output power type required for each group of the operating battery units; The output power corresponding to the output power type required by each group of operating battery cells is determined according to the output power type, the average SOC value, the average power and the SOC value of each group of operating battery cells.

8. The method according to claim 7, characterized in that Determining the output ratio of each group of the operating battery units according to the output power required by each group of the operating battery units and the target compensation power includes: Determine the sum and difference between the average power and a preset threshold value respectively; Based on the sum, the difference and the output power required by each group of the operating battery units, determine the actual output power of each group of operating battery units, and set a power allocation completion mark; Based on the actual output power and the target compensation power, an output ratio of each group of operating battery units is determined.

9. The method according to claim 8, characterized in that Based on the sum, the difference and the output power required by each group of the operating battery units, determining the actual output power of each group of operating battery units, and setting a power allocation completion mark, including: When the output power required by the operating battery unit is greater than the sum value, determining the actual output power to be the sum value, and setting a power allocation completion mark for the operating battery unit whose required output power is greater than the sum value; When the output power required by the operating battery unit is less than the difference, determining the actual output power to be the difference, and setting a power allocation completion mark for the operating battery unit whose required output power is less than the difference; When the output power required for operating the battery unit is greater than or equal to the difference and less than or equal to the sum, the first actual output power is determined to be the required output power.

10. The method according to claim 9, characterized in that After determining the actual output power of each group of operating battery cells based on the sum, the difference and the output power required by each group of operating battery cells and setting a power allocation completion mark, the method further includes: determining a sum of unallocated powers of all operating battery units based on the target compensation power, the actual output power and the first actual output power; Determine the operating battery unit for which the power allocation completion mark is not set; Determine an average value of unallocated power based on the total unallocated power and the number of operating battery units; For the operating battery unit for which the power allocation completion mark is not set, determining a second actual output power based on the unallocated power average value and the average SOC value; Based on the first actual output power and the second actual output power, the actual output power of the operating battery unit for which the power allocation completion flag is not set is determined, and the power allocation completion flag is set.

11. The method according to claim 1, characterized in that: Before obtaining the current state of charge SOC value of each group of operating battery cells in the plurality of groups of operating battery cells and the target compensation power determined according to the voltage change value of the power grid, the method further includes: Before each group of operating battery cells operates normally, pre-charging each group of battery cells to be operated to obtain a pre-charging result; When the pre-charging result indicates that the pre-charging is successful, each group of the battery cells to be operated is determined to be the operating battery cells.

12. A system controller, comprising a memory, a processor, and a determination program stored in the memory and executable on the processor, characterized in that: The processor is used to implement the method according to any one of claims 1-11 when executing the determination machine program.

13. A computer storage medium having a determination machine program stored thereon, wherein the determination machine program is used to implement the method according to any one of claims 1 to 11.

14. A battery energy storage system, characterized in that: The system includes a combiner cabinet unit and a plurality of parallel-connected operating battery units, wherein the combiner cabinet unit includes a system controller, wherein the system controller is respectively connected to each group of operating battery units in the plurality of parallel-connected operating battery units, and the system controller is connected to a power grid; The system controller is used to receive the voltage change value of the power grid and determine the target compensation power according to the voltage change value of the power grid; The system controller is also used to obtain the current state of charge (SOC) value of each group of operating battery cells in the multiple groups of operating battery cells; Determine the output power required by each group of the operating battery cells according to the current state of charge SOC value of each group of the operating battery cells, the target compensation power and a preset rule; determine the output ratio of each group of the operating battery cells according to the output power required by each group of the operating battery cells and the target compensation power; and send the output ratio to the operating battery cells corresponding to the output ratio; The operating battery unit is used to output corresponding power according to the received output ratio; Determining the output power required by each group of operating battery cells according to the current state of charge SOC value of each group of operating battery cells, the target compensation power and a preset rule; Determining average power based on the target compensation power and the number of operating battery units; Determine the sum and difference between the average power and a preset threshold value respectively; Based on the sum, the difference and the output power required by each group of the operating battery units, determine the actual output power of each group of the operating battery units, and set a power allocation completion mark; Based on the actual output power and the target compensation power, the output ratio required for each group of operating battery units is determined.

15. The system according to claim 14, characterized in that The system controller is connected to each group of operating battery units via a first branch or a second branch; When the first branch is in an open state and the second branch is in a closed state, the system controller is connected to the battery unit through the second branch, the second branch is used to perform pre-charging processing on each group of battery units to be operated to obtain a pre-charging result, and send the pre-charging result fed back by each group of battery units to be operated to the system controller, and the system controller is used to determine whether the battery unit to be operated is the operating battery unit according to the pre-charging result; When the first branch is in a closed state and the second branch is in an open state, the system controller is connected to each group of operating battery units through the first branch, and the first branch is used for data transmission between the system controller and each group of operating battery units.

16. The system according to claim 15, characterized in that The first branch includes a branch contactor, and the branch contactor is used to perform switching on or off according to a control instruction sent by the system controller.

17. The system according to claim 15, characterized in that The second branch includes a pre-charging resistor and a branch pre-charging contactor connected in series with the pre-charging resistor, and the branch pre-charging contactor is used to be connected or disconnected according to a control instruction sent by the system controller.

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