CN117353409A - Inter-cluster voltage equalization system and control method - Google Patents

Inter-cluster voltage equalization system and control method Download PDF

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Publication number
CN117353409A
CN117353409A CN202311171859.4A CN202311171859A CN117353409A CN 117353409 A CN117353409 A CN 117353409A CN 202311171859 A CN202311171859 A CN 202311171859A CN 117353409 A CN117353409 A CN 117353409A
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China
Prior art keywords
battery
cluster
balancing
relay
main
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CN202311171859.4A
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Chinese (zh)
Inventor
孙勇
彭宪州
彭秀花
任荭葳
丁纬达
韩旭来
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Zhejiang Windey Co Ltd
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Zhejiang Windey Co Ltd
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Priority to CN202311171859.4A priority Critical patent/CN117353409A/en
Publication of CN117353409A publication Critical patent/CN117353409A/en
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014—Circuits for equalisation of charge between batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4207—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells for several batteries or cells simultaneously or sequentially
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44—Methods for charging or discharging
    • H01M10/441—Methods for charging or discharging for several batteries or cells simultaneously or sequentially
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0013—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries acting upon several batteries simultaneously or sequentially
    • H02J7/0014—Circuits for equalisation of charge between batteries
    • H02J7/0019—Circuits for equalisation of charge between batteries using switched or multiplexed charge circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425—Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • H01M2010/4271—Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2207/00—Indexing scheme relating to details of circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J2207/20—Charging or discharging characterised by the power electronics converter
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention relates to a voltage equalization system and a control method between battery clusters, comprising a plurality of voltage equalization systems, a direct current power converter and a control unit; the voltage balancing system comprises a battery cluster, a main positive relay, a main negative relay, a pre-charging resistor, a balancing positive relay and a balancing negative relay; the control unit is used for controlling relay control in the battery stack system, total voltage of the battery cluster, total current detection and communication interaction with the direct current power converter; the invention adopts the independent inter-cluster balancing loop and the direct current power converter to realize rapid balancing of the inter-cluster voltage and capacity under the condition of not affecting the normal use of the cell stack system, thereby improving the usability of the system. The method solves the problems of long equalization time among the battery clusters, severe limit value of allowable equalization pressure difference range among the clusters and high system cost in the prior art.

Description

Inter-cluster voltage equalization system and control method
Technical Field
The invention relates to a system and a method for balancing voltage among battery clusters, and belongs to the technical field of balancing treatment among battery clusters.
Background
The energy storage system can form voltage and capacity differences among parallel battery clusters along with the prolonged working time and other reasons, so that the problems of inter-cluster circulation and the like are caused after the battery clusters are connected in parallel, and the use of products is affected. The current inter-cluster voltage and capacity balancing schemes for multi-cluster parallel battery systems mainly include the following three types:
scheme 1: the energy transfer and voltage balance among the battery clusters are realized by adopting a closed main negative and a pre-charging relay and using a pre-charging resistor as a circulation resistor, and the patent is referred to: CN113193633 a-battery cluster access method, apparatus, energy storage station, device and storage medium (hereinafter referred to as comparative document 1).
Scheme 2: the scheme of the battery cluster series power converter is adopted to realize the adjustment of the output power of each battery cluster, so that the balance of the voltage and the capacity among the battery clusters in the charging and discharging processes is realized. Reference is made to the patent: CN 218958570U-converters of energy storage systems and energy storage systems (hereinafter referred to as reference 2).
Scheme 3: and realizing the balance among the battery clusters by adopting a specific balance loop and a balance module. Reference is made to the patent: CN114243822 a-inter-cluster equalization regulation system (hereinafter referred to as comparative document 3).
The current comparison document 1 is limited by the power of the pre-charging resistor, the balanced current after passing through the pre-charging resistor and other factors, and has the following disadvantages: the voltage difference range allowing the inter-cluster voltage to be balanced is limited greatly, and the inter-cluster voltage balance of the battery cannot be realized under the working condition exceeding the specific voltage difference range; the voltage equalization of the battery cluster formed by the high-capacity battery cells needs too long, and the system maintenance requirement cannot be met.
The multi-cluster parallel energy storage system of comparative document 1 is shown in fig. 1, and generally consists of a control unit, a main positive relay, a main negative relay, a pre-charging resistor, and a battery cluster. When the control unit detects that the total voltage difference between the first battery cluster and the nth battery cluster is large, the function of circulating current among the battery clusters is realized by closing the pre-charging relay and the main negative relay, when the control unit detects that the circulating current is smaller than a threshold value, the voltage balancing among the clusters of the system is judged to be completed, the main positive relay is closed, the pre-charging relay is opened, and the voltage balancing and the high-voltage power-on of the multi-cluster parallel energy storage system are completed.
The current comparison document 2 is limited in that all battery clusters require a power converter, and the energy storage system is generally composed of 10 clusters, resulting in higher system cost.
The multi-cluster parallel energy storage system of comparative document 2 is shown as being generally composed of a control unit, a main positive relay, a main negative relay, a pre-charge resistor, a power converter, and a battery cluster. When the control unit detects that the total voltage difference between the first battery cluster and the nth battery cluster is large, the output power of the first battery cluster and the nth battery cluster is controlled by adjusting the power converter, so that the high-voltage power-on and capacity balance of the multi-cluster parallel energy storage system are realized.
In the comparison document 3, an independent balancing loop and an independent balancing module are adopted, but the system charge and discharge work of the cell stack system can not be carried out while the inter-cluster balancing of the cell clusters is carried out.
Disclosure of Invention
In order to overcome the defects of the prior researches, the invention provides a system for balancing the voltages among battery clusters and a control method. The independent inter-cluster balancing loop and the direct current power converter are adopted to realize rapid balancing of inter-cluster voltage and capacity under the condition that normal use of a cell stack system is not affected, and system availability is improved. The method solves the problems of long equalization time among the battery clusters, severe limit value of allowable equalization pressure difference range among the clusters and high system cost in the prior art.
A voltage equalization system and control method among battery clusters, including a plurality of voltage equalization systems, direct-current power converters and control units;
the voltage balancing system comprises a battery cluster, a main positive relay, a main negative relay, a pre-charging resistor, a balancing positive relay and a balancing negative relay;
in the voltage balancing system, a first battery cluster is always connected with a first main positive relay port, a first pre-charging relay port and a first balancing positive relay port; the other port of the first main positive relay is connected to the total positive port of the cell stack, and is kept in parallel connection with other cell clusters;
the other port of the first pre-charging relay is connected with a pre-charging resistor in series and then is connected to the total positive port of the cell stack; the other port of the first balancing positive relay is connected to the total positive output port of the direct current power converter;
the direct current power converter total positive input port is connected with the battery stack total positive port;
the total negative of the first battery cluster is connected with a first main negative relay port and a first balanced negative relay port, wherein the other port of the first total negative relay is connected with the total negative port of the battery stack; the first balancing negative relay is connected to the output port of the direct-current power converter headquarter; the input total negative port of the direct current power converter is connected with the total negative port of the battery stack;
the control unit is used for controlling relay control in the battery pile system, total voltage of the battery cluster, total current detection and communication interaction with the direct current power converter.
A control method of a voltage equalization system among battery clusters, wherein a plurality of clusters share a direct current power converter and realize voltage and capacity equalization by combining relay control in a single cluster, comprises the following steps: in stack rest mode:
step one: the control unit detects the voltages of the first battery cluster to the nth battery cluster and identifies the battery cluster with higher voltage and the battery cluster with lower voltage in the current multi-cluster energy storage system; or the control unit identifies the capacity difference of the current first battery cluster to the nth battery cluster;
step two: the control unit identifies whether the first battery cluster to the nth battery cluster have balanced requirements, and the batteries need to execute balanced power supply or balanced discharge or keep a static state;
step three: the control unit controls the battery clusters needing balanced power supply to close the balanced positive relay and the balanced negative relay, controls the battery clusters needing balanced discharge to close the main positive relay and the main negative relay, and controls the battery clusters needing to keep a static state to open all relays;
step four: the control unit recognizes the current or voltage required by the direct current power converter according to the capacity and the voltage difference among the battery clusters, and controls the equalization time of the battery clusters;
step five: and the control unit controls all the main positive relays of the battery clusters which are not powered on, and the main negative relays and the pre-charging relays sequentially act to finish the high-voltage powering-on of all the battery clusters.
A control method of a voltage equalization system among battery clusters is provided, wherein in a battery stack charging mode:
step one: the control unit detects the capacities of the first battery cluster to the nth battery cluster, identifies the battery cluster with high capacity in the current multi-cluster energy storage system, and balances the battery cluster with high capacity in the charging process;
step two: the method comprises the steps that a high-capacity battery cluster control unit is used for controlling a balancing positive relay and a balancing negative relay to be closed in a balancing mode, and a battery cluster without capacity balancing is used for controlling a main positive relay and a main negative relay to be closed;
step three: the control unit adjusts the charging current of the battery clusters according to the capacity difference among the battery clusters, so that the charging current I of the main loop is larger than the charging current I of the equalizing loop, and the capacity equalization completion target is met, I Main loop /I Equalization loop ＝(Soc Equalization completion –Soc Main loop )/(Soc Equalization completion –Soc Main loop )；
Step four: after the control unit recognizes that the inter-cluster balancing is finished, all the cluster balancing positive relays and the balancing negative relays are disconnected, the main positive relays and the main negative relays are closed, and a non-capacity balancing charging mode is entered.
A control method of a voltage equalization system among battery clusters is provided, wherein in a battery stacking electric mode:
step one: the control unit detects the capacities of the first battery cluster to the nth battery cluster, identifies the battery cluster with low capacity in the current multi-cluster energy storage system, and balances the battery cluster with low capacity in the discharging process;
step two: the method comprises the steps that a low-capacity battery cluster control unit is used for controlling a balancing positive relay and a balancing negative relay to be closed in a balancing mode, and a battery cluster without capacity balancing is used for controlling a main positive relay and a main negative relay to be closed;
step three: the control unit adjusts the discharging current of the battery clusters according to the capacity difference among the battery clusters, so that the discharging current I main loop of the main loop is larger than the discharging current I balance loop of the balance loop, and the capacity balance completion target is met, I Main loop /I Equalization loop ＝(Soc Main loop -Soc Equalization completion )/(Soc Main loop –Soc Equalization completion )；
Step four: after the control unit recognizes that the inter-cluster balancing is finished, all balancing positive relays and balancing negative relays are disconnected, the main positive relays and the main negative relays are closed, and a non-capacity balancing discharging mode is entered.
Compared with the prior art, the invention has the beneficial effects that:
compared with the traditional inter-cluster balancing scheme of controlling circulation through the precharge resistor, the invention greatly improves the balancing current among the battery clusters through the direct current power converter, and particularly aims at the large-capacity battery clusters, and can effectively shorten the balancing time.
The invention has strong adaptability, can meet the adjustment requirements of larger range of pressure difference and capacity difference among the battery clusters, is not limited to a standing state, and can realize capacity balance among the battery clusters in the charge and discharge process. Compared with the traditional inter-cluster balancing scheme of controlling circulation through the pre-charge resistor, the invention greatly improves the voltage difference range of the cell clusters allowing balancing to be started and reduces the power requirement on the pre-charge resistor by avoiding direct parallel connection among the cell clusters.
The invention has low cost. Compared with the traditional scheme that all battery clusters are provided with power converters, the power converter and n balanced positive relays are adopted, and the scheme of combined control of the n balanced negative relays obviously reduces the cost of the multi-cluster parallel energy storage system.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a comparison document 1;
FIG. 2 is a schematic diagram of comparative document 2;
FIG. 3 is a schematic diagram of a comparison document 3;
FIG. 4 is a schematic diagram of a system for equalizing voltage among battery clusters and a control method according to the present invention;
FIG. 5 is a flow chart of a method of equalizing control in the rest mode of the present invention;
FIG. 6 is a flow chart of an equalization control method in a charging mode of the present invention;
fig. 7 is a flowchart of an equalization control method in the discharge mode of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
A voltage equalization system and control method among battery clusters, including a plurality of voltage equalization systems, direct-current power converters and control units;
the voltage balancing system comprises a battery cluster, a main positive relay, a main negative relay, a pre-charging resistor, a balancing positive relay and a balancing negative relay;
in the voltage balancing system, a first battery cluster is always connected with a first main positive relay port, a first pre-charging relay port and a first balancing positive relay port; the other port of the first main positive relay is connected to the total positive port of the cell stack, and is kept in parallel connection with other cell clusters;
the other port of the first pre-charging relay is connected with a pre-charging resistor in series and then is connected to the total positive port of the cell stack; the other port of the first balancing positive relay is connected to the total positive output port of the direct current power converter;
the direct current power converter total positive input port is connected with the battery stack total positive port; (the DC power converter is to support bi-directional operation, so the input ports and output ports are used only to describe the scheme).
The total negative of the first battery cluster is connected with a first main negative relay port and a first balanced negative relay port, wherein the other port of the first total negative relay is connected with the total negative port of the battery stack; the first balancing negative relay is connected to the output port of the direct-current power converter headquarter; the input total negative port of the direct current power converter is connected with the total negative port of the battery stack; (the DC power converter is to support bi-directional operation, so the input ports and output ports are used only to describe the scheme).
The control unit is used for controlling relay control in the battery pile system, total voltage of the battery cluster, total current detection and communication interaction with the direct current power converter.
A control method of a voltage equalization system among battery clusters, wherein a plurality of clusters share a direct current power converter and realize voltage and capacity equalization by combining relay control in a single cluster, comprises the following steps: in stack rest mode:
step one: the control unit detects the voltages of the first battery cluster to the nth battery cluster and identifies the battery cluster with higher voltage and the battery cluster with lower voltage in the current multi-cluster energy storage system; or the control unit identifies the capacity difference of the current first battery cluster to the nth battery cluster;
step two: the control unit identifies whether the first battery cluster to the nth battery cluster have balanced requirements, and the batteries need to execute balanced power supply or balanced discharge or keep a static state;
step three: the control unit controls the battery clusters needing balanced power supply to close the balanced positive relay and the balanced negative relay, controls the battery clusters needing balanced discharge to close the main positive relay and the main negative relay, and controls the battery clusters needing to keep a static state to open all relays;
step four: the control unit recognizes the current or voltage required by the direct current power converter according to the capacity and the voltage difference among the battery clusters, and controls the equalization time of the battery clusters;
step five: and the control unit controls all the main positive relays of the battery clusters which are not powered on, and the main negative relays and the pre-charging relays sequentially act to finish the high-voltage powering-on of all the battery clusters.
The working of the invention is described in the following in a specific example. And after the control unit wakes up the self-check at low voltage and has no fault, the voltages of the first battery cluster to the nth battery cluster are obtained. After receiving the high-voltage power-on request, the following judgment is performed.
The voltage (capacity) for the first cluster is lower than the other cluster operating conditions of the stack system:
1) Closing a main negative relay and a pre-charging relay of the second battery cluster to the nth battery cluster; and closing the main positive relay after the voltage difference between two ends of the precharge resistors of the second battery cluster and the nth battery cluster is smaller than or equal to delta V1, and opening the precharge relay.
2) And closing the balancing negative relay and the balancing negative relay of the first battery cluster.
3) The control unit evaluates the charging direction of the system according to the voltages (capacity differences) of the first battery cluster and the second battery cluster to the nth battery cluster, and charges the first battery cluster through direct current power conversion when the battery stack is charged, and meanwhile, the control unit needs to set the charging current of the system as I.
4) And after the control unit identifies that the cell stack system meets the balance completion condition in the charging process, the control unit controls the direct current power converter to stop charging the first cell cluster of the stack, and turns off the balance positive relay and the balance negative relay.
And 5, closing the main negative relay and the pre-charging relay of the first battery cluster after the standing time of the battery stack system is more than or equal to T1 s, closing the main positive relay after the pressure difference of the two ends of the pre-charging resistor of the first battery cluster is less than or equal to delta V1, and opening the pre-charging relay.
And 6, balancing among the battery clusters and high-voltage boosting are completed.
The first battery cluster, the second battery cluster and the nth battery cluster are only convenient for understanding and classifying description; the first cluster in the actual working condition may represent a plurality of clusters that need to be balanced.
In this example, the direct current power converter controls the battery stack system to charge the first battery cluster only for convenience of understanding and description, and in actual working conditions, the direct current power converter can control the first battery cluster to discharge the battery stack system so as to achieve the purpose of balancing among the battery clusters.
A control method of a voltage equalization system among battery clusters is provided, wherein in a battery stack charging mode:
step one: the control unit detects the capacities of the first battery cluster to the nth battery cluster, identifies the battery cluster with high capacity in the current multi-cluster energy storage system, and balances the battery cluster with high capacity in the charging process;
step two: the method comprises the steps that a high-capacity battery cluster control unit is used for controlling a balancing positive relay and a balancing negative relay to be closed in a balancing mode, and a battery cluster without capacity balancing is used for controlling a main positive relay and a main negative relay to be closed;
step three: the control unit adjusts the charging current of the battery clusters according to the capacity difference among the battery clusters, so that the charging current I of the main loop is larger than the charging current I of the equalizing loop, and the capacity equalization completion target is met, I Main loop /I Equalization loop ＝(Soc Equalization completion –Soc Main loop )/(Soc Equalization completion –Soc Main loop )；
Step four: after the control unit recognizes that the inter-cluster balancing is finished, all the cluster balancing positive relays and the balancing negative relays are disconnected, the main positive relays and the main negative relays are closed, and a non-capacity balancing charging mode is entered.
A control method of a voltage equalization system among battery clusters is provided, wherein in a battery stacking electric mode:
step one: the control unit detects the capacities of the first battery cluster to the nth battery cluster, identifies the battery cluster with low capacity in the current multi-cluster energy storage system, and balances the battery cluster with low capacity in the discharging process;
step two: the method comprises the steps that a low-capacity battery cluster control unit is used for controlling a balancing positive relay and a balancing negative relay to be closed in a balancing mode, and a battery cluster without capacity balancing is used for controlling a main positive relay and a main negative relay to be closed;
step three: the control unit adjusts the discharging current of the battery clusters according to the capacity difference among the battery clusters, so that the discharging current I main loop of the main loop is larger than the discharging current I balance loop of the balance loop, and the capacity balance completion target is met, I Main loop /I Equalization loop ＝(Soc Main loop -Soc Equalization completion )/(Soc Main loop –Soc Equalization completion )；
Step four: after the control unit recognizes that the inter-cluster balancing is finished, all balancing positive relays and balancing negative relays are disconnected, the main positive relays and the main negative relays are closed, and a non-capacity balancing discharging mode is entered.
The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, and yet fall within the scope of the invention.

Claims (4)

1. A voltage equalization system and a control method between battery clusters are characterized in that: the DC power converter comprises a plurality of voltage equalization systems, a DC power converter and a control unit;
the voltage balancing system comprises a battery cluster, a main positive relay, a main negative relay, a pre-charging resistor, a balancing positive relay and a balancing negative relay;
in the voltage balancing system, a first battery cluster is always connected with a first main positive relay port, a first pre-charging relay port and a first balancing positive relay port; the other port of the first main positive relay is connected to the total positive port of the cell stack, and is kept in parallel connection with other cell clusters;
the other port of the first pre-charging relay is connected with a pre-charging resistor in series and then is connected to the total positive port of the cell stack; the other port of the first balancing positive relay is connected to the total positive output port of the direct current power converter;
the direct current power converter total positive input port is connected with the battery stack total positive port;
the total negative of the first battery cluster is connected with a first main negative relay port and a first balanced negative relay port, wherein the other port of the first total negative relay is connected with the total negative port of the battery stack; the first balancing negative relay is connected to the output port of the direct-current power converter headquarter; the input total negative port of the direct current power converter is connected with the total negative port of the battery stack;
the control unit is used for controlling relay control in the battery pile system, total voltage of the battery cluster, total current detection and communication interaction with the direct current power converter.
2. A control method of the inter-cluster voltage equalization system of claim 1, wherein: the method for realizing voltage and capacity balance by sharing one direct current power converter by multiple clusters and combining relay control in a single cluster comprises the following steps: in stack rest mode:
step one: the control unit detects the voltages of the first battery cluster to the nth battery cluster and identifies the battery cluster with higher voltage and the battery cluster with lower voltage in the current multi-cluster energy storage system; or the control unit identifies the capacity difference of the current first battery cluster to the nth battery cluster;
step two: the control unit identifies whether the first battery cluster to the nth battery cluster have balanced requirements, and the batteries need to execute balanced power supply or balanced discharge or keep a static state;
step three: the control unit controls the battery clusters needing balanced power supply to close the balanced positive relay and the balanced negative relay, controls the battery clusters needing balanced discharge to close the main positive relay and the main negative relay, and controls the battery clusters needing to keep a static state to open all relays;
step four: the control unit recognizes the current or voltage required by the direct current power converter according to the capacity and the voltage difference among the battery clusters, and controls the equalization time of the battery clusters;
step five: and the control unit controls all the main positive relays of the battery clusters which are not powered on, and the main negative relays and the pre-charging relays sequentially act to finish the high-voltage powering-on of all the battery clusters.
3. A control method of the inter-cluster voltage equalization system of claim 1, wherein: the method comprises the following steps: in the stack charging mode:
step one: the control unit detects the capacities of the first battery cluster to the nth battery cluster, identifies the battery cluster with high capacity in the current multi-cluster energy storage system, and balances the battery cluster with high capacity in the charging process;
step two: the method comprises the steps that a high-capacity battery cluster control unit is used for controlling a balancing positive relay and a balancing negative relay to be closed in a balancing mode, and a battery cluster without capacity balancing is used for controlling a main positive relay and a main negative relay to be closed;
step three: the control unit adjusts the charging current of the battery clusters according to the capacity difference among the battery clusters, so that the charging current I of the main loop is larger than the charging current I of the equalizing loop, and the capacity equalization completion target is met, I Main loop /I Equalization loop ＝(Soc Equalization completion –Soc Main loop )/(Soc Equalization completion –Soc Main loop )；
Step four: after the control unit recognizes that the inter-cluster balancing is finished, all the cluster balancing positive relays and the balancing negative relays are disconnected, the main positive relays and the main negative relays are closed, and a non-capacity balancing charging mode is entered.
4. A control method of the inter-cluster voltage equalization system of claim 1, wherein: the method comprises the following steps: in battery stacking electric mode:
step one: the control unit detects the capacities of the first battery cluster to the nth battery cluster, identifies the battery cluster with low capacity in the current multi-cluster energy storage system, and balances the battery cluster with low capacity in the discharging process;
step two: the method comprises the steps that a low-capacity battery cluster control unit is used for controlling a balancing positive relay and a balancing negative relay to be closed in a balancing mode, and a battery cluster without capacity balancing is used for controlling a main positive relay and a main negative relay to be closed;
step three: the control unit adjusts the discharging current of the battery clusters according to the capacity difference among the battery clusters, so that the discharging current I main loop of the main loop is larger than the discharging current I balance loop of the balance loop, and the capacity balance completion target is met, I Main loop /I Equalization loop ＝(Soc Main loop -Soc Equalization completion )/(Soc Main loop –Soc Equalization completion )；
Step four: after the control unit recognizes that the inter-cluster balancing is finished, all balancing positive relays and balancing negative relays are disconnected, the main positive relays and the main negative relays are closed, and a non-capacity balancing discharging mode is entered.
CN202311171859.4A 2023-09-12 2023-09-12 Inter-cluster voltage equalization system and control method Pending CN117353409A (en)

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