A control method of a battery cluster parallel system and a battery cluster parallel system

Abstract

The application discloses a kind of battery cluster parallel system control method and battery cluster parallel system, by first battery cluster as current battery cluster, the target parallel voltage when current battery cluster is calculated with maximum rated power of itself runs;Then the running power when each second battery cluster runs with target parallel voltage is calculated, and when it is judged that there is one of second battery cluster The absolute value of the running power is greater than the absolute value of maximum rated power of itself, the second battery cluster is taken as new current battery cluster to re-execute the step of calculating new target parallel voltage, until the absolute value of the running power of all second battery cluster is less than or equal to the absolute value of maximum rated power of itself;And the system maximum power of battery cluster parallel system is calculated based on the running power.Solve the problem that individual battery cluster power overruns caused by not considering the maximum charge-discharge power that each battery cluster can withstand when the power output of battery system is carried out at present stage.

Description

Technical Field

[0001] This invention relates to the field of battery management technology, and in particular to a control method and a parallel battery cluster system. Background Technology

[0002] Currently, battery systems are widely used in automobiles and energy storage, and with the development of the new energy industry, the market demand for battery capacity is increasing. To improve battery capacity, the number of batteries connected in series and parallel is constantly increasing. Multiple cells are connected in series and parallel to form a battery module, multiple battery modules are connected in series to form a battery cluster, and multiple battery clusters are connected in parallel to form a battery stack, such as... Figure 1 As shown. During the charging and discharging process, the Battery Management System (BMS) typically outputs the maximum acceptable charging and discharging power of the battery system, and the Power Conversion System (PCS) charges and discharges the battery system according to this power.

[0003] However, due to inconsistencies in individual cells, such as differences in voltage, temperature, state of charge (SOC), and internal resistance, the maximum charge and discharge power that each cluster can withstand is also inconsistent. If the same fixed power is output to the battery system, some cell clusters may exceed their power limits, affecting the lifespan of the battery system. Summary of the Invention

[0004] This invention provides a control method and a parallel battery cluster system, which solves the technical problem in the prior art where the maximum charge and discharge power that each battery cluster can withstand cannot be considered when outputting power to the battery system, resulting in the power over-limit of individual battery clusters.

[0005] This invention provides a control method for a parallel battery cluster system, the control method comprising:

[0006] The battery array management unit receives the intra-cluster resistance, open-circuit voltage, and maximum rated power of each battery cluster from the battery cluster management unit, wherein the maximum rated power includes the maximum charging power and the maximum discharging power;

[0007] The battery array management unit takes the first battery cluster as the current battery cluster and calculates the target parallel voltage of the current battery cluster when it operates at its maximum rated power.

[0008] The battery array management unit calculates the operating power of each second battery cluster when it operates at the target parallel voltage, and determines whether the absolute value of the operating power of each second battery cluster is less than or equal to the absolute value of its own maximum rated power, wherein the second battery cluster is a battery cluster other than the current battery cluster;

[0009] If the absolute value of the operating power of one of the second battery clusters is greater than the absolute value of its own maximum rated power, then the second battery cluster is used as the new current battery cluster and the step of calculating the new target parallel voltage is re-executed until the absolute value of the operating power of all the second battery clusters is less than or equal to the absolute value of their own maximum rated power.

[0010] If the absolute value of the operating power of each of the second battery clusters is less than or equal to the absolute value of its own maximum rated power, then the maximum system power of the parallel battery cluster system is calculated based on the operating power.

[0011] Furthermore, before the battery array management unit receives the intra-cluster resistance, open-circuit voltage, and maximum rated power of each battery cluster from the battery cluster management unit, the control method further includes:

[0012] Each battery cluster management unit calculates the internal resistance and open-circuit voltage of its respective battery cluster based on the parallel voltage and current of its battery cluster.

[0013] Each battery cluster management unit obtains the maximum rated power of its respective battery cluster;

[0014] Each of the battery cluster management units sends its own cluster resistance, open-circuit voltage, and maximum rated power to the battery array management unit.

[0015] Furthermore, each battery cluster management unit calculates the intra-cluster resistance and open-circuit voltage of its respective battery cluster based on the parallel voltage and current of that battery cluster, including:

[0016] Each battery cluster management unit samples the parallel voltage and current of its respective battery cluster twice at a preset sampling time interval Δt to obtain the first parallel voltage V. S (t), First current I i (t), Second parallel voltage V S (t+Δt) and the second current I i (t+△t);

[0017] Based on the first parallel voltage V S (t), the first current I i (t), the second parallel voltage V S (t+Δt) and the second current I i (t+△t), using the formula R i (t) = (V S (t) - V S (t+△t)) / (I i(t+△t) -I i (t) Calculate the cluster resistance R of the corresponding battery cluster. i (t), using the formula V i (t)=V S (t)+I i (t)×R i (t) Calculate the open-circuit voltage V of the corresponding battery cluster. i (t), where i is the number of the battery cluster.

[0018] Furthermore, each of the battery cluster management units acquires the maximum rated power of its respective battery cluster by:

[0019] Each battery cluster management unit determines the maximum charging power of each battery cluster by querying a preset charging power table, based on the maximum voltage, minimum temperature, maximum temperature of all individual cells in its respective battery cluster and the state of charge of the corresponding battery cluster.

[0020] Each battery cluster management unit determines the maximum discharge power of each battery cluster by querying a preset discharge power table, based on the minimum voltage, minimum temperature, maximum temperature of all individual cells in its respective battery cluster and the state of charge of the corresponding battery cluster.

[0021] Furthermore, the battery array management unit takes the first battery cluster as the current battery cluster and calculates the target parallel voltage of the current battery cluster when it operates at its maximum rated power, including:

[0022] The battery array management unit takes the first battery cluster as the current battery cluster and calculates the target parallel voltage of the current battery cluster when it operates at its maximum rated power according to the following formula:

[0023] V S (P DMi )=V1(t)-I1(P DMi )×R1(t);

[0024] V S (P CMi )=V1(t)-I1(P CMi )×R1(t);

[0025] P DMi =V S (P DMi )×I1(P DMi );

[0026] P CMi =V S (P CMi )×I1(P CMi );

[0027] Among them, P DMi For the maximum discharge power, P CMi For maximum charging power, V S (P DMi ) represents the first battery cluster at its maximum discharge power P DMi Target parallel voltage during operation, V S (P CMi ) represents the first battery cluster charging at maximum power P CMi The target parallel voltage during operation, I1(P) DMi The first battery cluster discharges at its maximum power P. DMi Cluster current during operation, I1(P) CMi The first battery cluster is charged at its maximum power P. CMi The cluster current during operation, V1(t) is the open-circuit voltage of the first battery cluster, R1(t) is the internal resistance of the first battery cluster, and i is the number of the battery cluster, which is 1.

[0028] Further, the battery array management unit calculates the operating power of each second battery cluster when operating at the target parallel voltage, and determines whether the absolute value of the operating power of each second battery cluster is less than or equal to the absolute value of its own maximum rated power, including:

[0029] The battery array management unit utilizes formula P i = (V S ×(V i - V1) + (P1×R1)) / R i Calculate the operating power of each second battery cluster when operating at the target parallel voltage; where P i V represents the operating power of the i-th second battery cluster. S The target parallel voltage for each of the second battery clusters, V S For V S (P DMi ) or V S (P CMi V i V1 is the open-circuit voltage of the i-th second battery cluster, V1 is the open-circuit voltage of the current battery cluster, P1 is the maximum rated power of the current battery cluster, and P1 is P DM1 or P CM1 R1 is the intra-cluster resistance of the current battery cluster. i The internal resistance of the second battery cluster;

[0030] Determine the absolute value of the operating power |P| of each of the second battery clusters. i|Is it less than or equal to the absolute value of its maximum rated power?|P s |, where |P s |for|P DMi |or|P CMi |

[0031] Furthermore, the maximum system power of the parallel battery cluster system calculated based on the aforementioned operating power includes:

[0032] Using formula The maximum power of the parallel battery cluster system is calculated, where P 系统 P is the maximum power of the system. i The operating power is N, and the total number of battery clusters is N.

[0033] Furthermore, after the battery array management unit calculates the maximum power of the parallel battery cluster system, the control method further includes:

[0034] The battery array management unit sends the system's maximum power to the energy storage converter;

[0035] The energy storage converter charges or discharges the parallel battery cluster system at the maximum power of the system.

[0036] This invention also provides a parallel battery cluster system, wherein the parallel battery cluster system executes the control method for the parallel battery cluster system described in any of the above embodiments;

[0037] The parallel battery cluster system includes a battery array management unit, multiple battery cluster management units, and multiple battery clusters;

[0038] One of the battery cluster management units is connected to one battery cluster;

[0039] Each of the battery clusters is electrically connected to the battery array management unit through its corresponding battery cluster management unit.

[0040] This invention also provides an energy storage battery system, which includes the parallel battery cluster system described in any of the above embodiments, and further includes an energy storage converter;

[0041] The parallel battery cluster system is electrically connected to the energy storage converter.

[0042] This invention discloses a control method and a parallel battery cluster system. The control method includes: a battery array management unit receiving the intra-cluster resistance, open-circuit voltage, and maximum rated power of each battery cluster from each battery cluster management unit; the battery array management unit using a first battery cluster as the current battery cluster and calculating the target parallel voltage for the current battery cluster when it operates at its maximum rated power; the battery array management unit calculating the operating power of each second battery cluster when it operates at the target parallel voltage and determining whether the absolute value of the operating power of each second battery cluster is less than or equal to the absolute value of its maximum rated power; if the absolute value of the operating power of any second battery cluster is greater than the absolute value of its maximum rated power, then the second battery cluster is used as the new current battery cluster and the step of calculating a new target parallel voltage is repeated until the absolute value of the operating power of all second battery clusters is less than or equal to the absolute value of their maximum rated power; if the absolute value of the operating power of each second battery cluster is less than or equal to the absolute value of its maximum rated power, then the maximum system power of the parallel battery cluster system is calculated based on the operating power. This application, by considering the internal resistance of the battery clusters, ensures that the charging and discharging power of all battery clusters is within an acceptable range. It solves the technical problem in the prior art where the maximum charging and discharging power that each battery cluster can withstand cannot be considered when outputting power to the battery system, resulting in the power over-limit of individual battery clusters. This achieves the technical effect of preventing overcurrent during charging and discharging of individual battery clusters, maximizing the lifespan of the battery system, and better utilizing battery performance. Attached Figure Description

[0043] Figure 1 This is a structural diagram of a parallel battery cluster system provided in an embodiment of the present invention;

[0044] Figure 2 This is a simplified circuit diagram of the parallel battery cluster system provided in the embodiments of the present invention;

[0045] Figure 3 This is a flowchart of a control method for a parallel battery cluster system provided in an embodiment of the present invention;

[0046] Figure 4 This is a flowchart of another control method for a parallel battery cluster system provided in an embodiment of the present invention. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0048] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this invention are used to distinguish different objects, not to limit a specific order. The various embodiments of this invention described below can be performed individually or in combination with each other; the embodiments of this invention do not impose specific limitations in this regard.

[0049] Figure 2 This is a simplified circuit diagram of the parallel battery cluster system provided in an embodiment of the present invention.

[0050] like Figure 2 As shown, V1, V2, ..., V N These are the open-circuit voltages of each battery cluster, R1, R2, ..., R N Let I1, I2, ..., In be the internal resistances of each battery cluster. N I represents the cluster current of each battery cluster. bus Where is the total system current, and N is the total number of battery clusters.

[0051] Taking discharge as an example, let P be the actual discharge power of each battery cluster. DRi The maximum discharge power of each battery cluster is P. DMi Where i ∈ (1, 2, ..., N), i is the cell cluster number. It can be deduced that there must exist a cell cluster such that when this cell cluster is P... DMi During operation, all other battery clusters satisfy P DRi ≤ P DMi The total discharge power of the system at this point is the maximum discharge power of the system. The key formula is given below.

[0052] According to Ohm's law, the parallel voltage V of each battery cluster can be obtained. S satisfy:

[0053] Formula (1): V S = V1 - I1×R1 = V2 - I2×R2 = ... = V N - I N ×R N ;

[0054] The power of each battery cluster satisfies: Formula (2): P i = V S ×I i ;

[0055] Combining formulas (1) and (2), we can obtain formula (3): P i = V S ×(V i - V1 + (I1×R1)) / R i ;

[0056] When the first battery cluster discharges at its maximum discharge power P DM1 When running, we have: Formula (4): P DM1 = V S ×I1;

[0057] Combining formulas (3) and (4), we get: Formula (5): P i = (V S ×(V i - V1) + (P DM1 ×R1)) / R i ;

[0058] It should be noted that the open-circuit voltage V in formula (5) i and cluster resistance R i It is difficult to obtain directly by sampling; what can be obtained directly by sampling is the parallel voltage V. S and the cluster current I of each battery cluster i Compared to the current, the open-circuit voltage V of each battery cluster is... i and cluster resistance R i The change is slow or inconspicuous, therefore it can be assumed that the open-circuit voltage V changes within a relatively short time interval Δt. i and cluster resistance R i If the voltage remains constant, then a parallel voltage V can be used. S and cluster current I i The open-circuit voltage V was estimated. i and cluster resistance R i .

[0059] Let the current time be t, and the next time be t+Δt. According to formula (1), we can obtain:

[0060] Formula (6): V S (t) = V i (t) - I i (t) ×R i (t);

[0061] Formula (7): V S (t+△t) = V i (t+△t) - I i (t+△t)×R i (t+△t);

[0062] When Δt is short, we have:

[0063] Formula (8): R i (t) = R i (t+△t);

[0064] Formula (9): V i(t) = V i (t+△t);

[0065] Combining formulas (6), (7), (8), and (9), we can obtain:

[0066] Formula (10): R i (t) = (V S (t) - V S (t+△t)) / (I i (t+△t) - I i (t));

[0067] Formula (11): V i (t) = V S (t) + I i (t)×R i (t).

[0068] Figure 3 This is a flowchart of a control method for a parallel battery cluster system provided in an embodiment of the present invention.

[0069] like Figure 3 As shown, based on the above formulas, the control method for this parallel battery cluster system specifically includes the following steps:

[0070] S101, the battery array management unit receives the cluster resistance, open circuit voltage and maximum rated power of the battery cluster sent by each battery cluster management unit, wherein the maximum rated power includes the maximum charging power and the maximum discharging power.

[0071] Specifically, the Battery Array Unit (BAU) collects the open-circuit voltage V of each battery cluster from the battery cluster management unit (BCU). i (t), Cluster resistance R i (t) and maximum rated power P s Among them, the maximum rated power P s Including maximum charging power P CMi and maximum discharge power P DMi If the maximum charging power of the system needs to be calculated, then the maximum rated power P should be used, depending on the subsequent calculation requirements. s The maximum charging power P in CMi If it is necessary to calculate the maximum discharge power of the system, then use the maximum rated power P. s The maximum discharge power P in DMi .

[0072] S102, the battery array management unit takes the first battery cluster as the current battery cluster and calculates the target parallel voltage of the current battery cluster when it is running at its maximum rated power.

[0073] Specifically, taking the calculation of the system's maximum discharge power as an example, after the battery array management unit obtains the relevant parameters of each battery cluster, it first takes the first battery cluster as the current battery cluster, and assumes that the current battery cluster has its maximum discharge power P. DM1 By running the above formulas (1) and (4), we can obtain:

[0074] Equation (1): V S (P DM1 ) = V1(t) - I1(P DM1 )×R1(t);

[0075] Equation (2): P DM1 = V S (P DM1 )×I1(P DM1 );

[0076] Among them, P DM1 V1(t) and R1(t) are known quantities obtained from the corresponding battery cluster management unit. S (P DM1 ), I1(P DM1 The first battery cluster discharges at its maximum power P. DM1 The parallel voltage and cluster current during operation can be obtained by solving equations (1) and (2) to obtain V. S (P DM1 This yields the target parallel voltage.

[0077] S103, the battery array management unit calculates the operating power of each second battery cluster when it is running at the target parallel voltage, and determines whether the absolute value of the operating power of each second battery cluster is less than or equal to the absolute value of its own maximum rated power, wherein the second battery cluster is the battery cluster other than the current battery cluster.

[0078] Specifically, after obtaining the target parallel voltage V S (P DM1 After that, the battery array management unit will set the target parallel voltage V. S (P DM1 The maximum discharge power P of the first battery cluster DM1 Open-circuit voltage V of each battery cluster i (t) and the cluster resistance R of each battery cluster i Substituting (t) into formula (5), the operating power P of each second battery cluster can be calculated. i Then determine the absolute value of the operating power |P| of each second battery cluster. i|Are all values ​​less than or equal to the absolute value of their maximum discharge power?|P DMi |

[0079] It should be noted that since the current direction is different during battery charging and discharging, in energy storage applications, the discharging current is usually considered positive and the charging current is considered negative. Therefore, when using actual values ​​to calculate P, the obtained P will be different. DMi For a positive value, P CMi The value is negative, therefore the operating power P is... i With maximum discharge power P DMi Or maximum charging power P CMi When making comparisons, the absolute values ​​of each parameter are used for comparison, which will not be elaborated here.

[0080] S104 If the absolute value of the operating power of one of the second battery clusters is greater than the absolute value of its own maximum rated power, then the second battery cluster is used as the new current battery cluster and the step of calculating the new target parallel voltage is re-executed until the absolute value of the operating power of all the second battery clusters is less than or equal to the absolute value of their own maximum rated power.

[0081] Specifically, if the judgment result is that there exists a second battery cluster that does not meet the absolute value of the operating power |P i | less than or equal to the absolute value of its maximum discharge power|P DMi If |, it indicates that the operating power obtained by operating at the target parallel voltage exceeds the maximum power that the second battery cluster can withstand. In this case, the second battery cluster that does not meet the condition needs to be taken as the new current battery cluster, and it is assumed that it operates at the maximum discharge power of the new current battery cluster. Then, according to the above formulas (1) and (4), the new target parallel voltage is recalculated, that is, return to step S102. Similarly, the new operating power P of each battery cluster is calculated. i And re-compare the absolute values ​​of the new operating power of each battery cluster |P i |Are all values ​​less than or equal to the absolute value of their maximum discharge power?|P DMi If the condition is not met, the current battery cluster is replaced sequentially until the last battery cluster meets the absolute value of the operating power |P. i | less than or equal to the absolute value of its maximum discharge power|P DMi | conditions.

[0082] It should be noted that, similarly, for charging power, we only need to consider the maximum discharge power P. DMi Replace with maximum charging power P CMi That's all; I won't go into details here.

[0083] S105, if the absolute value of the operating power of each second battery cluster is less than or equal to the absolute value of its own maximum rated power, then the maximum system power of the parallel battery cluster system is calculated based on the operating power.

[0084] Specifically, the system's maximum power includes the system's maximum charging power and maximum discharging power. This embodiment of the invention takes the discharging process as an example. If the absolute value of the operating power of each second battery cluster is |P i |All are less than or equal to the absolute value of their maximum discharge power|P DMi |, then This is the maximum discharge power of the parallel battery cluster system. Similarly, the calculation of the maximum charging power of the system only requires converting the maximum discharge power P... DMi Replace with maximum charging power P CMi That's all; I won't go into details here.

[0085] This application, by considering the internal resistance of the battery clusters, ensures that the charging and discharging power of all battery clusters is within an acceptable range. It solves the technical problem in the prior art where the maximum charging and discharging power that each battery cluster can withstand cannot be considered when outputting power to the battery system, resulting in the power over-limit of individual battery clusters. This achieves the technical effect of preventing overcurrent during charging and discharging of individual battery clusters, maximizing the lifespan of the battery system, and better utilizing battery performance.

[0086] Based on the above technical solutions, Figure 4 This is a flowchart of another control method for a parallel battery cluster system provided in an embodiment of the present invention. Figure 4 As shown, prior to S101, the control method further includes:

[0087] S401, each battery cluster management unit calculates the intra-cluster resistance and open-circuit voltage of its respective battery cluster based on the parallel voltage and current of its battery cluster.

[0088] S402, each battery cluster management unit obtains the maximum rated power of its respective battery cluster.

[0089] S403, each battery cluster management unit sends its own cluster resistance, open-circuit voltage, and maximum rated power to the battery array management unit.

[0090] Based on the above technical solutions, S401 specifically includes:

[0091] Each battery cluster management unit samples the parallel voltage and current of its respective battery cluster twice at a preset sampling time interval Δt, obtaining the first parallel voltage V. S (t), First current I i (t), Second parallel voltage V S(t+Δt) and the second current I i (t+△t);

[0092] Based on the first parallel voltage V S (t), First current I i (t), Second parallel voltage V S (t+Δt) and the second current I i (t+△t), using the formula R i (t) = (V S (t) - V S (t+△t)) / (I i (t+△t) - I i (t) Calculate the cluster resistance R of the corresponding battery cluster. i (t), using the formula V i (t) = V S (t) + I i (t)×R i (t) Calculate the open-circuit voltage V of the corresponding battery cluster. i (t), where i is the number of the battery cluster.

[0093] Based on the above technical solutions, S402 specifically includes:

[0094] Each battery cluster management unit determines the maximum charging power P of each battery cluster by querying a preset charging power table, based on the maximum voltage, minimum temperature, maximum temperature of all individual cells in its respective battery cluster, and the state of charge of the corresponding battery cluster. CMi ;

[0095] Each battery cluster management unit determines the maximum discharge power P of each battery cluster by consulting a preset discharge power table, based on the minimum voltage, minimum temperature, maximum temperature of all individual cells in its respective battery cluster, and the state of charge of the corresponding battery cluster. DMi .

[0096] Based on the above technical solutions, S102 specifically includes:

[0097] The battery array management unit takes the first battery cluster as the current battery cluster and calculates the target parallel voltage of the current battery cluster when it operates at its maximum rated power according to the following formula:

[0098] V S (P DMi )=V1(t)-I1(P DMi )×R1(t);

[0099] V S (P CMi )=V1(t)-I1(PCMi )×R1(t);

[0100] P DMi =V S (P DMi )×I1(P DMi );

[0101] P CMi =V S (P CMi )×I1(P CMi );

[0102] Among them, P DMi For the maximum discharge power, P CMi For maximum charging power, V S (P DMi The first battery cluster discharges at its maximum power P. DMi Target parallel voltage during operation, V S (P CMi The first battery cluster is charged at its maximum power P. CMi The target parallel voltage during operation, I1(P) DMi The first battery cluster discharges at its maximum power P. DMi Cluster current during operation, I1(P) CMi The first battery cluster is charged at its maximum power P. CMi The cluster current during operation, V1(t) is the open-circuit voltage of the first battery cluster, R1(t) is the internal resistance of the first battery cluster, and i is the number of the battery cluster, with the first battery cluster numbered 1.

[0103] Based on the above technical solutions, S103 specifically includes:

[0104] The battery array management unit utilizes formula P i = (V S ×(V i - V1) + (P1×R1)) / R i Calculate the operating power of each second battery cluster when operating at the target parallel voltage; where P i V represents the operating power of the i-th second battery cluster. S The target parallel voltage for each second battery cluster, V S For V S (P DMi ) or V S (P CMi V i Let V1 be the open-circuit voltage of the i-th second battery cluster, V1 be the open-circuit voltage of the current battery cluster, P1 be the maximum rated power of the current battery cluster, and P1 be the P value. DM1 or P CM1R1 is the internal resistance of the current battery cluster, R i The internal resistance of the second battery cluster;

[0105] Determine the absolute value of the operating power of each second battery cluster |P i |Is it less than or equal to the absolute value of its maximum rated power?|P s |,|P s |for|P DMi |or|P CMi |

[0106] Based on the above technical solutions, S105, the maximum system power of the parallel battery cluster system calculated based on the operating power specifically includes:

[0107] Using formula The maximum power of the parallel battery cluster system is calculated, where P 系统 P is the system's maximum power. i Where N is the operating power and N is the total number of battery clusters.

[0108] Based on the above technical solutions, after S105, the control method further includes: the battery array management unit sends the system's maximum power to the energy storage converter; the energy storage converter charges or discharges the battery cluster parallel system at the system's maximum power.

[0109] This invention also provides a parallel battery cluster system, which executes the control method for the parallel battery cluster system in any of the above embodiments; such as Figure 1 As shown, the parallel battery cluster system includes a battery array management unit (BAU) and multiple battery cluster management units (BCUs). Figure 1 To distinguish them, BCU1, BCU2, ..., BCUN ​​represent the battery cluster management units from the first battery cluster to the Nth battery cluster, and multiple battery clusters A ( Figure 1 To distinguish them, A1, A2, ..., AN represent the first to the Nth battery clusters; one battery cluster management unit (BCU) is connected to one battery cluster A; each battery cluster A is electrically connected to the battery array management unit (BAU) through its corresponding battery cluster management unit (BCU).

[0110] Specifically, such as Figure 1 As shown, the battery array management unit (BAU) includes positive L0+ and negative L0-. Each battery cluster A includes multiple battery boxes. The battery boxes in a battery cluster A are connected in series, and the battery clusters A are connected in parallel. The battery boxes in the first battery cluster A1 are numbered 1-1, 1-2, ..., 1-N, the battery boxes in the second battery cluster A2 are numbered 2-1, 2-2, ..., 2-N, and so on.

[0111] The parallel battery cluster system provided in this embodiment executes the control method of the parallel battery cluster system in the above embodiment. Therefore, the parallel battery cluster system provided in this embodiment also has the beneficial effects described in the above embodiment, which will not be repeated here.

[0112] This invention also provides an energy storage battery system, which includes the parallel battery cluster system in any of the above embodiments, and further includes an energy storage converter; the parallel battery cluster system is electrically connected to the energy storage converter.

[0113] The energy storage battery system provided in this embodiment of the invention includes the parallel battery cluster system in the above embodiments. Therefore, the energy storage battery system provided in this embodiment of the invention also has the beneficial effects described in the above embodiments, which will not be repeated here.

[0114] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0115] Finally, it should be noted that the above are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A control method for a parallel battery cluster system, characterized in that, The control method includes: The battery array management unit receives the intra-cluster resistance, open-circuit voltage, and maximum rated power of each battery cluster from the battery cluster management unit, wherein the maximum rated power includes the maximum charging power and the maximum discharging power; The battery array management unit takes the first battery cluster as the current battery cluster and calculates the target parallel voltage of the current battery cluster when it operates at its maximum rated power. The battery array management unit calculates the operating power of each second battery cluster when it operates at the target parallel voltage, and determines whether the absolute value of the operating power of each second battery cluster is less than or equal to the absolute value of its own maximum rated power, wherein the second battery cluster is a battery cluster other than the current battery cluster; If the absolute value of the operating power of one of the second battery clusters is greater than the absolute value of its own maximum rated power, then the second battery cluster is used as the new current battery cluster and the step of calculating the new target parallel voltage is re-executed until the absolute value of the operating power of all the second battery clusters is less than or equal to the absolute value of their own maximum rated power. If the absolute value of the operating power of each of the second battery clusters is less than or equal to the absolute value of its own maximum rated power, then the maximum system power of the parallel battery cluster system is calculated based on the operating power.

2. The control method for the parallel battery cluster system according to claim 1, characterized in that, Before the battery array management unit receives the intra-cluster resistance, open-circuit voltage, and maximum rated power of each battery cluster from the battery cluster management unit, the control method further includes: Each battery cluster management unit calculates the internal resistance and open-circuit voltage of its respective battery cluster based on the parallel voltage and current of its battery cluster. Each battery cluster management unit obtains the maximum rated power of its respective battery cluster; Each of the battery cluster management units sends its own cluster resistance, open-circuit voltage, and maximum rated power to the battery array management unit.

3. The control method for the parallel battery cluster system according to claim 2, characterized in that, Each battery cluster management unit calculates the internal resistance and open-circuit voltage of its respective battery cluster based on the parallel voltage and current of that battery cluster, including: Each battery cluster management unit samples the parallel voltage and current of its respective battery cluster twice at a preset sampling time interval Δt to obtain the first parallel voltage V. S (t), First current I i (t), Second parallel voltage V S (t+Δt) and the second current I i (t+△t); Based on the first parallel voltage V S (t), the first current I i (t), the second parallel voltage V S (t+Δt) and the second current I i (t+△t), using the formula R i (t) = (V S (t) - V S (t+△t)) / (I i (t+△t) - I i (t) Calculate the cluster resistance R of the corresponding battery cluster. i (t), using the formula V i (t)=V S (t)+I i (t)×R i (t) Calculate the open-circuit voltage V of the corresponding battery cluster. i (t), where i is the number of the battery cluster.

4. The control method for the parallel battery cluster system according to claim 2, characterized in that, Each of the battery cluster management units obtains the maximum rated power of its respective battery cluster, including: Each battery cluster management unit determines the maximum charging power of each battery cluster by querying a preset charging power table, based on the maximum voltage, minimum temperature, maximum temperature of all individual cells in its respective battery cluster and the state of charge of the corresponding battery cluster. Each battery cluster management unit determines the maximum discharge power of each battery cluster by querying a preset discharge power table, based on the minimum voltage, minimum temperature, maximum temperature of all individual cells in its respective battery cluster and the state of charge of the corresponding battery cluster.

5. The control method for the parallel battery cluster system according to claim 1, characterized in that, The battery array management unit takes the first battery cluster as the current battery cluster and calculates the target parallel voltage of the current battery cluster when it operates at its maximum rated power, including: The battery array management unit takes the first battery cluster as the current battery cluster and calculates the target parallel voltage of the current battery cluster when it operates at its maximum rated power according to the following formula: V S (P DMi )=V1(t)-I1(P DMi )×R1(t); V S (P CMi )=V1(t)-I1(P CMi )×R1(t); P DMi =V S (P DMi )×I1(P DMi ); P CMi =V S (P CMi )×I1(P CMi ); Among them, P DMi For the maximum discharge power, P CMi For maximum charging power, V S (P DMi ) represents the first battery cluster at its maximum discharge power P DMi Target parallel voltage during operation, V S (P CMi ) represents the first battery cluster charging at maximum power P CMi The target parallel voltage during operation, I1(P) DMi The first battery cluster discharges at its maximum power P. DMi Cluster current during operation, I1(P) CMi The first battery cluster is charged at its maximum power P. CMi The cluster current during operation, V1(t) is the open-circuit voltage of the first battery cluster, R1(t) is the internal resistance of the first battery cluster, and i is the number of the battery cluster, which is 1.

6. The control method for the parallel battery cluster system according to claim 5, characterized in that, The battery array management unit calculates the operating power of each second battery cluster when operating at the target parallel voltage, and determines whether the absolute value of the operating power of each second battery cluster is less than or equal to the absolute value of its own maximum rated power, including: The battery array management unit utilizes formula P i = (V S ×(V i - V1) + (P1×R1)) / R i Calculate the operating power of each second battery cluster when operating at the target parallel voltage; where P i V represents the operating power of the i-th second battery cluster. S The target parallel voltage for each of the second battery clusters, V S For V S (P DMi ) or V S (P CMi V i V1 is the open-circuit voltage of the i-th second battery cluster, V1 is the open-circuit voltage of the current battery cluster, P1 is the maximum rated power of the current battery cluster, and P1 is P DM1 or P CM1 R1 is the intra-cluster resistance of the current battery cluster. i The internal resistance of the second battery cluster; Determine the absolute value of the operating power |P| of each of the second battery clusters. i |Is it less than or equal to the absolute value of its maximum rated power?|P s |, where |P s |for|P DMi |or|P CMi | 7. The control method for the parallel battery cluster system according to claim 1, characterized in that, The maximum system power of the parallel battery cluster system, calculated based on the aforementioned operating power, includes: Using formula The maximum power of the parallel battery cluster system is calculated, where P 系统 P is the maximum power of the system. i The operating power is N, and the total number of battery clusters is N.

8. The control method for the parallel battery cluster system according to claim 1, characterized in that, After the battery array management unit calculates the maximum power of the parallel battery cluster system, the control method further includes: The battery array management unit sends the system's maximum power to the energy storage converter; The energy storage converter charges or discharges the parallel battery cluster system at the maximum power of the system.

9. A parallel battery cluster system, characterized in that, The parallel battery cluster system executes the control method of the parallel battery cluster system according to any one of claims 1-8; The parallel battery cluster system includes a battery array management unit, multiple battery cluster management units, and multiple battery clusters; One of the battery cluster management units is connected to one battery cluster; Each of the battery clusters is electrically connected to the battery array management unit through its corresponding battery cluster management unit.

10. An energy storage battery system, characterized in that, The energy storage battery system includes the parallel battery cluster system as described in claim 9, and further includes an energy storage converter; The parallel battery cluster system is electrically connected to the energy storage converter.

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