High-voltage battery cluster merging control system and method

Abstract

The invention discloses a cluster combining control system and method for high-voltage battery clusters, and the system comprises batteries which are connected in series to form battery packs, and each battery pack is managed and controlled by a battery pack main control module; the battery pack main control module comprises a temperature sampling circuit, a first voltage and current sampling circuit, a DCDC circuit, a switch matrix circuit and a CAN bus communication circuit. The DCDC circuit and the first battery pack are connected in series to form a second battery pack, and a plurality of second battery packs are connected in series to form a battery cluster; each battery cluster is managed and controlled by a battery cluster main control module, and the battery cluster main control module controls a plurality of battery pack main control modules at the lower level to carry out equalization and voltage stabilization operation; the upper level of the battery cluster main control module is provided with an energy storage system main control module, and the energy storage system main control module obtains state information of each battery cluster and controls the lower level battery cluster main control module to perform cluster merging. The circulating current influence between the battery clusters is reduced, the risk that the battery clusters are overheated or damaged is avoided, and the service life of the battery is prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage batteries, and in particular to a high-voltage battery cluster parallel control system and method. Background Art

[0002] At present, energy storage systems generally use a method of connecting multiple batteries in series to form a battery group, then forming a certain number of battery groups into a battery cluster, and finally connecting multiple battery clusters in parallel to increase the capacity of the energy storage system. However, due to the inconsistency of batteries, there will be a voltage difference when battery clusters are connected in parallel. The battery cluster with high voltage will charge the battery cluster with low voltage, thereby generating inter-cluster circulation. Inter-cluster circulation will increase battery energy loss and reduce system efficiency. When the circulation is too large, it will also affect the life of the battery, and in more serious cases, it will burn out the circuit and cause safety accidents.

[0003] The existing technology mainly uses pre-charging resistors to reduce inter-cluster circulating currents. The main function of the pre-charging resistor is to pre-charge the battery cluster through a resistor before the battery cluster is connected in parallel, so that its voltage gradually approaches the voltage of other battery clusters, thereby reducing the impact current and circulating current during parallel connection. However, the pre-charging process takes a certain amount of time, especially when the voltage difference between the battery clusters is large. This may prolong the system startup and parallel connection time, affecting the system's rapid response capability. At the same time, during the pre-charging process, heat is generated when the current passes through the pre-charging resistor, resulting in energy loss. Especially in high-power systems, the energy loss may be considerable. Summary of the invention

[0004] In view of the above problems, the present invention proposes a high-voltage battery cluster parallel control system and method, by which the circulating current influence occurring when the battery clusters are paralleled is reduced, thereby achieving safe and reliable paralleling of the battery clusters.

[0005] In order to solve the above technical problems, the present invention provides a high-voltage battery cluster control system, including: a plurality of batteries are connected in series to form a battery pack, and each battery pack is managed and controlled by a battery pack master control module BMU. The battery pack master control module BMU mainly includes a temperature sampling circuit, a first voltage and current sampling circuit, a DCDC circuit, a switch matrix circuit and a CAN bus communication circuit; the battery pack master control module BMU uses an STM32 series or other series of single-chip microcomputers as the main control chip.

[0006] The temperature sampling circuit includes multiple temperature sensors, each of which is arranged in the heat-sensitive area of ​​the battery. The temperature sensor is directly connected to the main control chip of the battery pack main control module BMU, and converts the collected analog signal into a digital signal and transmits it to the battery pack main control module BMU for analysis and processing.

[0007] The first voltage and current sampling circuit is composed of a high-precision voltage sensor and a current sensor, which are used to monitor the voltage and current changes of the battery unit in real time. The output ends of the voltage sensor and the current sensor are connected to the analog-to-digital converter ADC, and the ADC then sends the data to the main control module for analysis and processing.

[0008] The DCDC circuit is connected in series with the first battery pack to form a second battery pack, and multiple second battery packs are connected in series to form a battery cluster. Preferably, the low-voltage positive port of the DCDC circuit is connected to the positive electrode of the second battery pack, the low-voltage negative port is connected to the positive electrode of the first battery pack, the high-voltage positive port is connected to the positive electrode of the first battery pack, and the high-voltage negative port is connected to the negative electrode of the first battery pack;

[0009] The switch matrix circuit is combined with the DCDC circuit for active balancing within the battery pack before clustering. After balancing is completed, the switch matrix circuit is switched, and the DCDC circuit is switched to a voltage stabilization mode so that the second battery pack outputs a constant voltage. Preferably, each battery in the battery pack is divided into odd-numbered batteries and even-numbered batteries according to the sequence. The positive poles of the odd-numbered batteries (i.e., the negative poles of the even-numbered batteries) are connected to polarity switches S3 and S4 through a switch, and the negative poles of the odd-numbered batteries (i.e., the positive poles of the even-numbered batteries) are connected to polarity switches S1 and S2 through a switch. Polarity switches S1 and S3, S2 and S4 are connected to the low-voltage positive port and the low-voltage negative port of the DCDC circuit, respectively.

[0010] The CAN bus communication circuit is directly connected to the data interface of the main control chip, and is equipped with a CAN controller and a physical layer transceiver, so as to realize bidirectional data exchange between the battery pack main control module BMU and the upper-level battery cluster main control module BCMU.

[0011] Furthermore, several battery packs are connected in series to form a battery cluster, and each battery cluster is managed and controlled by a battery cluster master control module BCMU. The battery cluster master control module BCMU controls multiple lower-level battery pack master control modules BMU to perform balancing and voltage stabilization operations. The battery cluster master control module BCMU mainly includes a contactor control circuit, a second voltage and current sampling circuit, an insulation resistance detection circuit, and a CAN bus communication circuit; the battery cluster master control module BCMU uses an STM32 series or other series of single-chip microcomputers as the main control chip.

[0012] The second voltage and current sampling circuit is preferably used to obtain voltage and current information through Hall voltage sensors and Hall current sensors to monitor the safety status of the battery cluster. The output ends of the Hall voltage sensor and Hall current sensor are connected to the ADC, and the ADC then sends the data to the battery cluster master control module BCMU for analysis and processing. Before clustering, it is necessary to sample the battery cluster voltage to determine whether its voltage meets the clustering conditions;

[0013] The insulation resistance detection circuit is used to detect the positive insulation resistance and negative insulation resistance of the battery cluster and output the detection result to the battery cluster master control module BCMU. Before clustering, it is necessary to obtain the positive insulation resistance and negative insulation resistance of the corresponding battery cluster to determine whether it meets the clustering conditions;

[0014] The contactor control circuit is composed of a fuse, a circuit breaker and a positive and negative contactor. The high-voltage positive electrode of the battery cluster is connected to the positive contactor, which is then connected to the fuse, which is then connected to the circuit breaker, and the circuit breaker is directly connected to the positive electrode of the DC bus. The high-voltage negative electrode of the battery cluster is directly connected to the DC bus through the negative contactor. The fuse, circuit breaker and positive and negative contactors are all directly controlled by the main control chip.

[0015] The CAN bus communication circuit is equipped with a CAN controller and a physical layer transceiver to realize bidirectional data exchange between the battery pack master control module BMU and the battery cluster master control module BCMU, and between the battery cluster master control module BCMU and the energy storage system master control module BSMU.

[0016] The battery pack master control module BMU, the battery cluster master control module BCMU and the energy storage system master control module BSMU use a single-chip microcomputer as the main control chip.

[0017] Furthermore, an energy storage system master control module BSMU is also provided above the multiple battery cluster master control modules BCMU. The master control module obtains the status information of each battery cluster through the CAN bus communication circuit and controls the multiple battery cluster master control modules BCMU at the lower level to perform cluster operation.

[0018] Accordingly, the present invention also provides a high-voltage battery cluster parallel control method applied to the above-mentioned high-voltage battery cluster parallel control system, and the control method comprises the following steps:

[0019] Step 1: The energy storage system master control module BSMU initiates a data upload request instruction to the battery cluster master control modules BCMU1 to BCMUn through the CAN bus communication circuit.

[0020] Step 2: The battery cluster master control module BCMUi obtains the battery cluster voltage and the positive and negative insulation resistance of the battery cluster through the battery cluster voltage and current sampling circuit and the insulation resistance detection circuit according to the request data upload instruction, and uploads the corresponding information to the energy storage system master control module BSMU through the CAN bus communication circuit.

[0021] Step 3: The energy storage system master control module BSMU selects a battery cluster that meets the clustering conditions according to the battery cluster voltage and positive and negative insulation resistance information uploaded by the battery cluster master control modules BCMU1 to BCMUn, and sends a same battery group voltage reference V to each BCMU that meets the clustering conditions.

[0022] Step 4: The battery cluster master control module BCMUi that meets the clustering conditions controls the multiple lower-level battery group master control modules BMU through the CAN bus to perform balancing control first. After balancing is completed, the battery group master control module BMU is controlled to switch to the voltage regulation mode to stabilize each battery group to the battery group voltage reference V.

[0023] Step 5: After the battery cluster master control module BCMUi detects that each of the lower-level battery group master control modules BMU has reached the voltage reference V, the corresponding battery cluster is connected to the DC bus through the contactor control circuit.

[0024] Furthermore, the method for controlling the battery cluster master control module BCMU to control the lower-level multiple battery group master control modules BMU in the above step 4 includes the following steps:

[0025] Step 4.1, the battery cluster master control module BCMU initiates a data upload request instruction to the battery pack master control modules BMU1~BMUn through the CAN bus communication circuit.

[0026] Step 4.2, the battery cluster master control module BCMU calculates the SOC of each battery according to the voltage and current data uploaded by the battery pack master control module BMUi. After the calculation is completed, a balancing command is sent to the battery pack master control module BMUi to control it to balance the batteries that are not within the preset SOC threshold.

[0027] Step 4.3: The battery pack master control module BMUi controls the DCDC circuit and the switch matrix circuit to balance the corresponding batteries, and returns new voltage and current data to the battery cluster master control module BCMU to iteratively update the SOC.

[0028] Step 4.4: When the battery cluster master control module BCMU calculates that a battery group has been balanced, it sends a command to control it to switch to the voltage regulation mode so that its output voltage is stabilized at the voltage reference V.

[0029] Step 4.5: The battery cluster master control module BCMU detects that each battery group at the lower level is switched to the voltage regulation mode and the output voltage is stabilized at the voltage reference V, and performs the cluster parallel operation.

[0030] The present invention has the following characteristics and beneficial effects:

[0031] The present invention obtains the cluster voltage and insulation resistance of the battery cluster in real time through the CAN bus before clustering, ensuring the safety and reliability of the battery cluster to be incorporated. Each battery pack realizes switching between the balancing and voltage stabilization modes through the DCDC circuit and the switch matrix circuit. Before clustering, each battery is first balanced according to the SOC to ensure that the SOC of each battery in the battery cluster is consistent, thereby improving the battery life and battery cycle life. After the balancing is completed, it is switched to the voltage stabilization mode to make the output voltage of each battery cluster incorporated into the busbar consistent, thereby reducing the circulation impact between the battery clusters, avoiding the risk of overheating or damage of the battery cluster, extending the service life of the battery, and enhancing the stability and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

[0033] Figure 1 It is a circuit principle block diagram of the high-voltage battery cluster parallel control system of the present invention;

[0034] Figure 2 is a circuit principle block diagram of a single battery pack of the present invention;

[0035] Figure 3 It is a logic control block diagram of battery cluster paralleling of the present invention;

[0036] Figure 4 It is a circuit principle block diagram of an insulation resistance sampling circuit involved in the present invention;

[0037] Figure 5 This is a diagram of the equalization result of the main control module of the battery pack of the present invention;

[0038] Description of reference numerals:

[0039] Energy storage system main control module BSMU; battery cluster main control module BCMU; battery pack main control module BMU; positive contactor KM1; negative contactor KM2; switch matrix switches K1~Kn; polarity switches S1~S4; positive insulation resistor RP; negative insulation resistor RN; resistor RSP; resistor RSN; resistor RAMC; switch SP; switch SN; isolation operational amplifier OP1; operational amplifier OP2; voltage source U1. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0041] This example provides a high-voltage battery cluster parallel control system, such as Figure 2 As shown, several batteries are connected in series to form a battery pack, and each battery pack is managed and controlled by a battery pack master control module BMU. The battery pack master control module BMU mainly includes a temperature sampling circuit, a first voltage and current sampling circuit, a DCDC circuit, a switch matrix circuit and a CAN bus communication circuit. The battery pack master control module BMU uses an STM32 series or other series of single-chip microcomputers as the main control chip.

[0042] The temperature sampling circuit includes a plurality of temperature sensors, each of which is arranged in the heat-sensitive area of ​​the battery. The temperature sensor is directly connected to the main control chip, and converts the collected analog signal into a digital signal and transmits it to the main control module for analysis and processing.

[0043] The first voltage and current sampling circuit is composed of a high-precision voltage sensor and a current sensor, which is used to monitor the voltage and current changes of the battery unit in real time. The output end of the sensor is connected to the ADC, and the ADC then sends the data to the main control module for analysis and processing.

[0044] The DCDC circuit is connected in series with the first battery pack to form a second battery pack, and multiple second battery packs are connected in series to form a battery cluster. Preferably, the low-voltage positive port of the DCDC circuit is connected to the positive electrode of the second battery pack, the low-voltage negative port is connected to the positive electrode of the first battery pack, the high-voltage positive port is connected to the positive electrode of the first battery pack, and the high-voltage negative port is connected to the negative electrode of the first battery pack.

[0045] The switch matrix circuit is combined with the DCDC circuit to be used for active balancing in the battery pack before clustering. After balancing is completed, the switch matrix circuit is switched, and the DCDC circuit is switched to a voltage stabilization mode, so that the second battery pack outputs a constant voltage.

[0046] Specifically, Figure 2 As shown, each battery in the battery pack is divided into odd-numbered batteries and even-numbered batteries according to the sequence. The positive poles of the odd-numbered batteries (i.e., the negative poles of the even-numbered batteries) are connected to polarity switches S3 and S4 through a switch, and the negative poles of the odd-numbered batteries (i.e., the positive poles of the even-numbered batteries) are connected to polarity switches S1 and S2 through a switch. Polarity switches S1 and S3, S2 and S4 are connected to the low-voltage positive port and low-voltage negative port of the DCDC circuit respectively.

[0047] When the SOC of the nth battery in the battery pack is not within the preset threshold range, the battery pack master control module BMU first controls switches kn and kn+1 in the switch matrix circuit to open, and then controls two of the polarity switches S1 to S4 to open (only one of S1 and S2 can be opened at the same time, and only one of S3 and S4 can be opened at the same time), and finally controls the DCDC circuit to start forward balancing or reverse balancing.

[0048] After balancing is completed, the battery pack master control module BMU switches to voltage stabilization mode. In voltage stabilization mode, the switches and polarity switches in the switch matrix circuit are disconnected, and the battery pack master control module BMU uses the difference between the current battery pack voltage and the preset battery pack voltage reference as feedback to control the DCDC circuit to stabilize the battery pack voltage at the preset battery pack voltage reference.

[0049] The CAN bus communication circuit is directly connected to the data interface of the main control chip, and is equipped with a CAN controller and a physical layer transceiver, so as to realize bidirectional data exchange between the battery pack main control module BMU and the upper-level battery cluster main control module BCMU.

[0050] Further, if Figure 1 As shown, several battery packs are connected in series to form a battery cluster, and each battery cluster is managed and controlled by a battery cluster master control module BCMU. The battery cluster master control module BCMU controls multiple lower-level battery pack master control modules BMU to perform balancing and voltage stabilization operations. The battery cluster master control module BCMU mainly includes a contactor control circuit, a second voltage and current sampling circuit, an insulation resistance detection circuit, and a CAN bus communication circuit; the battery cluster master control module BCMU uses an STM32 series or other series of single-chip microcomputers as the main control chip.

[0051] The second voltage and current sampling circuit preferably obtains voltage and current information through a Hall voltage sensor and a Hall current sensor to monitor the safety status of the battery cluster. Before clustering, it is necessary to sample the battery cluster voltage to determine whether its voltage meets the clustering conditions;

[0052] Furthermore, in this example, a Hall voltage sensor of model HNV-1000T is used. Two HNV-1000Ts are connected in parallel with the battery cluster and the busbar, respectively, and the results are output to the BCMU for data processing, thereby obtaining the battery cluster voltage data; in this example, a Hall current sensor of model HNC-300LT is used. When assembling HNC-300LT, the DC busbar needs to be paralleled through the sensor. The output result of HNC-300LT is a constant current output, so it is necessary to convert the result into a voltage output through a precision resistor and then output it to the BCMU for data processing, thereby obtaining the current data.

[0053] The insulation resistance detection circuit is used to detect the positive insulation resistance and negative insulation resistance of the battery cluster. Before clustering, the positive insulation resistance and negative insulation resistance of the corresponding battery cluster need to be obtained to determine whether it meets the clustering conditions;

[0054] Specifically, Figure 4 As shown, the insulation resistance detection circuit includes a positive insulation resistor RP, a negative insulation resistor RN, a resistor RSP, a resistor RSN, a resistor RAMC, a switch SP, a switch SN, an isolation operational amplifier OP1, an operational amplifier OP2 and a voltage source U1.

[0055] The positive insulation resistor RP and the negative insulation resistor RN are virtual resistors of the battery cluster, which can be regarded as the resistance between the positive and negative electrodes of the battery cluster and the earth. The switch SP, the resistor RSP and the resistor RAMC are connected in series and then connected in parallel at both ends of the resistor RP. The switch SN, the resistor RSN and the resistor RAMC are connected in series and then connected in parallel at both ends of the resistor RN. The two ends of the resistor RAMC are respectively connected to the two input ends of the isolation operational amplifier OP1, and the two output ends of the isolation operational amplifier OP1 are respectively connected to the two input ends of the operational amplifier OP2, and then the output end of the operational amplifier OP2 is connected to its reverse input end to form a reverse proportional amplification circuit. Finally, the sampling result is output to the BCMU for data processing, so as to obtain the insulation resistance data.

[0056] The contactor control circuit is composed of a fuse, a circuit breaker and a positive and negative contactor. The high-voltage positive electrode of the battery cluster is connected to the positive contactor, which is then connected to the fuse, which is then connected to the circuit breaker, and the circuit breaker is directly connected to the positive electrode of the DC bus. The high-voltage negative electrode of the battery cluster is directly connected to the DC bus through the negative contactor. The fuse, circuit breaker and positive and negative contactors are all directly controlled by the main control chip.

[0057] The CAN bus communication circuit is directly connected to the data interface of the main control chip, equipped with a CAN controller and a physical layer transceiver, and realizes bidirectional data exchange between the battery cluster main control module BCMU and the lower-level battery pack main control module BMU and the upper-level energy storage system main control module BSMU.

[0058] Furthermore, there is also an energy storage system master control module BSMU above the multiple battery cluster master control modules BCMU. The master control module obtains the status information of each battery cluster through the CAN bus communication circuit and controls the multiple battery cluster master control modules BCMU at the lower level to perform cluster operation.

[0059] Accordingly, the present invention also provides a control method applied to the above-mentioned high-voltage battery cluster parallel control system, such as Figure 2 and Figure 3 As shown, the control method comprises the following steps:

[0060] Step 1. The energy storage system master control module BSMU initiates a request data upload instruction to the battery cluster master control modules BCMU1~BCMUn through the CAN bus communication circuit. Furthermore, when the corresponding battery cluster master control module BCMUi receives the request data upload instruction, it will immediately return a response message to the energy storage system master control module BSMU. If the BSMU does not receive the response information from the corresponding battery cluster master control module BCMUi within 20MS, it will resend the request data upload instruction and wait for 40MS. If the BSMU does not receive the response information from the corresponding battery cluster master control module BCMUi within 40MS, it will resend the request data upload instruction and wait for 80MS. If the BSMU does not receive the response information from the corresponding battery cluster master control module BCMUi within 80MS, it is considered that the battery cluster master control module BCMUi has sent a response failure and will no longer perform cluster paralleling operations on it.

[0061] Step 2: The battery cluster master control module BCMUi obtains the battery cluster voltage and the positive and negative insulation resistance of the battery cluster through the battery cluster voltage and current sampling circuit and the insulation resistance detection circuit respectively, and uploads the corresponding information to the energy storage system master control module BSMU through the CAN bus communication circuit.

[0062] Further, the detection method of the insulation resistance detection circuit in the step 2 is:

[0063] Assume that the battery cluster voltage obtained by the battery cluster voltage and current sampling circuit is V.

[0064] First, the control switch SP is closed and the switch SN is opened. If the voltage drop across the resistor RP is VP, then Kirchhoff's voltage law gives:

[0065]

[0066] Assume that the voltage drop across the resistor RAMC is V1, then

[0067]

[0068] Similarly, the control switch SN is closed and the switch SP is opened. If the voltage drop across the resistor RN is VN, then Kirchhoff's voltage law gives:

[0069] electricity

[0070]

[0071] Assume that the voltage drop across the resistor RAMC is V2, then

[0072]

[0073] Assuming the resistance values ​​of resistors RSP and RSN are both RST, combining formulas (1) and (3), we can obtain:

[0074]

[0075]

[0076] VN and VP can be derived from formula (2) (4). V1 and V2 in formula (2) (4) can be calculated in the following way: the voltage drop generated on the resistor RAMC is output as a differential analog voltage signal through the isolation amplifier OP1, and then the analog voltage signal is output to the BCMU through the differential signal to single-ended signal circuit composed of the operational amplifier OP2. After the data processing of the BCMU, the insulation resistance data is obtained.

[0077] Step 3: The energy storage system master control module BSMU selects a battery cluster that meets the clustering conditions based on the battery cluster voltage and positive and negative insulation resistance information uploaded by the battery cluster master control modules BCMU1~BCMUn. If the cluster voltage of a battery cluster is not within the preset range, it is considered that the battery cluster voltage is faulty and the clustering operation will not be performed. If the positive and negative insulation resistance of a battery cluster is not within the preset range, it is considered that the insulation resistance of the battery cluster is faulty and the clustering operation will not be performed. If the battery cluster meets the clustering conditions, a same battery group voltage reference V is sent to each BCMU that meets the clustering conditions.

[0078] Step 4: The battery cluster master control module BCMUi that meets the clustering conditions controls the multiple lower-level battery group master control modules BMU through the CAN bus to perform balancing control first. After balancing is completed, the battery group master control module BMU is controlled to switch to the voltage stabilization mode, so that each battery group stabilizes to the battery group voltage reference V;

[0079] Step 5: After the battery cluster master control module BCMUi detects that each of the lower-level battery group master control modules BMU has reached the voltage reference V, the corresponding battery cluster is connected to the DC bus through the contactor control circuit;

[0080] Furthermore, in step 4, the method for controlling the battery cluster master control module BCMU to control the lower-level multiple battery group master control modules BMU includes the following steps:

[0081] Step 4.1, the battery cluster master control module BCMU initiates a data upload request instruction to the battery pack master control modules BMU1~BMUn through the CAN bus communication circuit;

[0082] Step 4.2, the battery cluster master control module BCMU calculates the SOC of each battery according to the voltage and current data uploaded by the battery pack master control module BMUi. After the calculation is completed, a balancing command is sent to the battery pack master control module BMUi to control it to balance the batteries that are not within the preset SOC threshold;

[0083] Step 4.3, the battery pack master control module BMUi controls the DCDC circuit and the switch matrix circuit to balance the corresponding battery, and returns the new voltage and current data to the battery cluster master control module BCMU to iteratively update the SOC;

[0084] Step 4.4, when the battery cluster master control module BCMU calculates that a battery group has been balanced, it sends a command to control it to switch to the voltage regulation mode so that its output voltage is stabilized at the voltage reference V;

[0085] Step 4.5, the battery cluster master control module BCMU detects that each group of batteries at the lower level is switched to the voltage regulation mode, and the output voltage is stabilized at the voltage reference V, and performs the cluster operation;

[0086] In this embodiment, each battery group includes 12 single cells. The balancing effect of a battery group is as follows: Figure 5 As shown in the figure, the initial SCO values ​​of the 12 single cells are 60%, 58%, 56%, 54%, 52%, 50%, 48%, 46%, 44%, 42%, 40%, and 38% respectively. After balancing, the SOC of each battery tends to be consistent. After balancing, the voltage of each group is set to 26.4V. After verification, the voltage of each battery group is actually stable at 26.4V, and the voltage of the entire battery cluster is stable at 792V. As a result, the voltage difference of each battery cluster when clustering is within the threshold range, and the overall circulation loss is minimized.

[0087] Obviously, the embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A high-voltage battery cluster parallel control system, characterized in that: include: Several batteries are connected in series to form a battery pack, and each battery pack is managed and controlled by a battery pack master control module BMU; The battery pack master control module BMU comprises a temperature sampling circuit, a first voltage and current sampling circuit, a DCDC circuit, a switch matrix circuit and a CAN bus communication circuit.

2. A high-voltage battery cluster parallel control system according to claim 1, characterized in that: The temperature sampling circuit includes a plurality of temperature sensors, which are respectively arranged in the heat-sensitive areas of the battery; the temperature sensor is directly connected to the main control chip of the battery pack main control module BMU, and converts the collected analog signal into a digital signal and transmits it to the battery pack main control module BMU for analysis and processing; The first voltage and current sampling circuit is composed of a voltage sensor and a current sensor, which monitor the voltage and current changes of the battery unit in real time; the output ends of the voltage sensor and the current sensor are connected to the analog-to-digital converter ADC, and the ADC then sends the data to the main control module for analysis and processing; The DCDC circuit is connected in series with the first battery pack to form a second battery pack, and multiple second battery packs are connected in series to form a battery cluster; the positive port 1 of the DCDC circuit is connected to the positive electrode of the second battery pack, the negative port 1 is connected to the positive electrode of the first battery pack, the positive port 2 is connected to the positive electrode of the first battery pack, and the negative port 2 is connected to the negative electrode of the first battery pack.

3. A high-voltage battery cluster parallel control system according to claim 2, characterized in that: The switch matrix circuit is combined with the DCDC circuit for active balancing within the battery pack before clustering; After the balancing is completed, the switch matrix circuit is switched, and the DCDC circuit is switched to a voltage stabilization mode, so that the second battery group outputs a constant voltage; Each battery in the battery pack is divided into odd-numbered batteries and even-numbered batteries according to the sequence; the positive poles of the odd-numbered batteries, that is, the negative poles of the even-numbered batteries, are connected to polarity switches S3 and S4 through a switch, and the negative poles of the odd-numbered batteries, that is, the positive poles of the even-numbered batteries, are connected to polarity switches S1 and S2 through a switch; polarity switches S1 and S3, S2 and S4 are respectively connected to the positive port 1 and the negative port 1 of the DCDC circuit.

4. A high-voltage battery cluster parallel control system according to claim 3, characterized in that: Each battery cluster is managed and controlled by a battery cluster master control module BCMU, which controls multiple lower-level battery pack master control modules BMU to perform balancing and voltage stabilization operations; the battery cluster master control module BCMU includes a contactor control circuit, a second voltage and current sampling circuit, an insulation resistance detection circuit and a CAN bus communication circuit.

5. A high-voltage battery cluster parallel control system according to claim 4, characterized in that: The second voltage and current sampling circuit obtains voltage and current information through the Hall voltage sensor and the Hall current sensor to monitor the safety status of the battery cluster; the output ends of the Hall voltage sensor and the Hall current sensor are connected to the ADC, and the ADC then sends the data to the battery cluster main control module BCMU for analysis and processing; Before clustering, the battery cluster voltage is sampled to determine whether the voltage meets the clustering conditions; The insulation resistance detection circuit detects the positive insulation resistance and negative insulation resistance of the battery cluster, outputs the detection result to the battery cluster master control module BCMU, obtains the positive insulation resistance and negative insulation resistance of the corresponding battery cluster before cluster connection, and determines whether it meets the cluster connection conditions; The contactor control circuit is composed of a fuse, a circuit breaker and positive and negative contactors; the positive pole of the battery cluster is connected to the positive contactor, the positive contactor is connected to the fuse, the fuse is connected to the circuit breaker, and the circuit breaker is directly connected to the positive pole of the DC bus; the negative pole of the battery cluster is directly connected to the DC bus through the negative contactor; the fuse, circuit breaker and positive and negative contactors are all directly controlled by the main control chip.

6. A high-voltage battery cluster parallel control system according to claim 5, characterized in that: An energy storage system master control module BSMU is provided above the multiple battery cluster master control modules BCMU. The master control module BSMU obtains the status information of each battery cluster through the CAN bus communication circuit and controls the multiple battery cluster master control modules BCMU at the lower level to perform cluster parallel operation.

7. A high-voltage battery cluster parallel control system according to claim 6, characterized in that: The CAN bus communication circuit is equipped with a CAN controller and a physical layer transceiver to realize bidirectional data exchange between the battery pack master control module BMU and the battery cluster master control module BCMU, and between the battery cluster master control module BCMU and the energy storage system master control module BSMU.

8. The high-voltage battery cluster parallel control system according to claim 7, characterized in that: The battery pack master control module BMU, the battery cluster master control module BCMU and the energy storage system master control module BSMU use a single-chip microcomputer as the main control chip.

9. A high-voltage battery cluster parallel control method, used to implement the high-voltage battery cluster parallel control system according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: The energy storage system master control module BSMU initiates a data upload request to the battery cluster master control modules BCMU1 to BCMUn through the CAN bus communication circuit; Step 2: The battery cluster master control module BCMUi obtains the battery cluster voltage and the positive and negative insulation resistance of the battery cluster through the battery cluster voltage and current sampling circuit and the insulation resistance detection circuit according to the request data upload instruction, and uploads the corresponding information to the energy storage system master control module BSMU through the CAN bus communication circuit; Step 3: The energy storage system master control module BSMU selects a battery cluster that meets the clustering conditions according to the battery cluster voltage and positive and negative insulation resistance information uploaded by the battery cluster master control modules BCMU1 to BCMUn, and sends a same battery group voltage reference V to each BCMU that meets the clustering conditions; Step 4: The battery cluster master control module BCMUi that meets the clustering conditions controls the multiple lower-level battery group master control modules BMU through the CAN bus to perform balancing control first; after the balancing is completed, the battery group master control module BMU is controlled to switch to the voltage stabilization mode, so that each battery group is stabilized to the battery group voltage reference V; Step 5: After the battery cluster master control module BCMUi detects that each of the lower-level battery group master control modules BMU has reached the voltage reference V, the corresponding battery cluster is connected to the DC bus through the contactor control circuit.

10. A high-voltage battery cluster parallel control method according to claim 9, characterized in that: The specific implementation process of step 4 is as follows: Step 4.1, the battery cluster master control module BCMU initiates a data upload request instruction to the battery pack master control modules BMU1~BMUn through the CAN bus communication circuit; Step 4.2, the battery cluster master control module BCMU calculates the SOC of each battery according to the voltage and current data uploaded by the battery pack master control module BMUi; then sends a balancing command to the battery pack master control module BMUi to control it to balance the batteries that are not within the preset SOC threshold; Step 4.3, the battery pack master control module BMUi controls the DCDC circuit and the switch matrix circuit to balance the corresponding battery, and returns the new voltage and current data to the battery cluster master control module BCMU to iteratively update the SOC; Step 4.4, when the battery cluster master control module BCMU calculates that a battery group has been balanced, it sends a command to control it to switch to the voltage regulation mode so that its output voltage is stabilized at the voltage reference V; Step 4.5: The battery cluster master control module BCMU detects that each battery group at the lower level is switched to the voltage regulation mode and the output voltage is stabilized at the voltage reference V, and performs the cluster parallel operation.

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