CN117977501A - Battery pack - Google Patents

Battery pack Download PDF

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Publication number
CN117977501A
CN117977501A CN202310963711.8A CN202310963711A CN117977501A CN 117977501 A CN117977501 A CN 117977501A CN 202310963711 A CN202310963711 A CN 202310963711A CN 117977501 A CN117977501 A CN 117977501A
Authority
CN
China
Prior art keywords
cell group
battery
battery pack
switching tube
voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310963711.8A
Other languages
Chinese (zh)
Inventor
李华佳
程从智
陈保国
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huawei Digital Power Technologies Co Ltd
Original Assignee
Huawei Digital Power Technologies Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Digital Power Technologies Co Ltd filed Critical Huawei Digital Power Technologies Co Ltd
Priority to CN202310963711.8A priority Critical patent/CN117977501A/en
Publication of CN117977501A publication Critical patent/CN117977501A/en
Pending legal-status Critical Current

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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
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28—Arrangements for balancing of the load in a network by storage of energy
    • H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
    • 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
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • H02J3/381—Dispersed generators
    • 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
    • H02J7/00304—Overcurrent protection
    • 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
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • 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
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H02J7/35—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering with light sensitive cells
    • 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

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The application provides an energy storage system, which comprises a battery cluster, wherein the battery cluster is coupled with a direct-current power supply and a load through a direct-current bus, the battery cluster comprises a plurality of battery packs, the battery packs comprise a controller, a first battery cell group, a second battery cell group and a plurality of switch tubes, the negative electrode of the first battery cell group is connected with the positive electrode of the second battery cell group through the first switch tube and the second switch tube, the positive electrode of the first battery cell group is connected with the negative electrode of the second battery cell group through a third switch tube and a fourth switch tube, and the connecting ends of the first switch tube and the second switch tube are connected with the connecting ends of the third switch tube and the fourth switch tube. The controller controls each switching tube based on the voltages at two ends of the first cell group and the second cell group so as to access or bypass any cell group in the battery pack. By adopting the application, the whole battery pack can be prevented from being cut under the condition that the battery pack is provided with the normally working battery cell groups, the charge states of all the battery cell groups are actively balanced, the control accuracy of the battery pack is higher, and the utilization rate of the battery cell groups is improved.

Description

Battery pack
The present application is a divisional application, the original application number is 202310125047.X, the original application date is 2023, month 01 and 18, and the entire contents of the original application are incorporated herein by reference.
Technical Field
The application relates to the field of electronic power, in particular to an energy storage system.
Background
Along with the large-scale access of the new energy power supply system to the power grid, the requirements of electric power peak clipping and valley filling, voltage and frequency regulation, micro-grid development and the like, the importance of the energy storage system is increasingly remarkable. Because the nominal voltage of the single battery core is lower, the energy storage system generally comprises a battery pack formed by connecting a plurality of battery core groups in series, and then the battery pack is connected in series to form a battery cluster so as to realize the improvement of the power supply voltage and the capacity of the energy storage system. When the energy storage system operates for a long time, battery pack faults (or unbalanced voltages) can affect the charging and discharging capacities of the battery clusters, and in the existing battery energy storage system, the whole fault battery pack is generally cut off to avoid the fault battery pack from affecting the charging and discharging of the battery clusters. However, when the battery pack fails because part of the battery cell groups in the battery pack cannot work normally, the battery cell groups in the failure battery pack still work normally, and the mode of cutting off the whole battery pack can lead to low utilization rate of the battery cell groups, so that the control precision of the battery pack is low.
Disclosure of Invention
The application provides an energy storage system, which can avoid cutting out the whole battery pack under the condition that the battery pack still has normally working battery cell groups in the fault battery pack, actively balance the charge states of all the battery cell groups, has higher control precision of the battery pack, improves the utilization rate of the battery cell groups and has higher charge and discharge efficiency of the energy storage system.
In a first aspect, the present application provides an energy storage system, where the energy storage system includes a battery cluster, where the battery cluster is coupled to a dc power supply and a load through a dc bus, the battery cluster includes a plurality of battery packs connected in series, the battery packs include a controller, a first battery cell group, a second battery cell group, and a plurality of switching tubes, a negative electrode of the first battery cell group is connected to a positive electrode of the second battery cell group through the first switching tube and the second switching tube connected in series, a positive electrode of the first battery cell group is connected to a negative electrode of the second battery cell group through a third switching tube and a fourth switching tube connected in series, a connection end of the first switching tube and the second switching tube is connected to a connection end of the third switching tube and the fourth switching tube, a positive electrode of the first battery cell group is used as a first input/output end of the battery pack, and a negative electrode of the second battery cell group is used as a second input/output end of the battery pack. The controller is used for controlling the switching tubes to be switched on or off based on the voltages at the two ends of the first battery cell group and the second battery cell group so as to be connected with or bypass any battery cell group in the battery pack.
In the application, when the battery pack fails or is unbalanced in the energy storage system, the battery cell group (all or part of the battery cell groups in the battery pack) with the failure or the unbalanced voltage in the battery pack is cut out of the battery cluster where the failure battery pack is located by the controller, and the battery cell group which normally works in the failure battery pack is reserved. For example, when the first battery cell group in the battery pack fails or has unbalanced voltage, and the second battery cell group works normally, the controller can control each switch tube to bypass the first battery cell group in the battery pack so as to cut out the battery cluster where the failed battery pack is located, and to connect the second battery cell group into the battery cluster so as to continue charging and discharging, so that the situation that the battery cell group which works normally is cut out under the condition that the battery cell group which works normally still exists in the failed battery pack is avoided, the control precision of the battery pack is higher, the charge state balancing effect of the battery cell group is enhanced, the utilization rate of the battery cell group is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a first possible implementation manner, the controller is configured to control the third switching tube and the fourth switching tube to be turned on and the first switching tube and the second switching tube to be turned off when a first voltage across the first battery cell group and a second voltage across the second battery cell group are greater than a charging threshold value, so as to bypass the first battery cell group and the second battery cell group. In addition, the controller may further control each switching tube (for example, control the first switching tube and the second switching tube to be turned on and control the third switching tube and the fourth switching tube to be turned off) to re-connect the first battery cell group and the second battery cell group to the battery cluster when the first voltage and the second voltage are not greater than the charging threshold. The battery pack in the energy storage system cuts out a battery cluster where the battery pack is located from a battery cell group with overhigh voltage (namely unbalanced voltage) in the battery pack through the controller, and the battery cell group with normal voltage in the battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the battery pack is prevented from being cut out under the condition that the battery pack is provided with the normally working battery cell group, the control precision of the battery pack is higher, the utilization rate of the battery cell group is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a second possible implementation manner, the controller is configured to control the third switching tube and the fourth switching tube to be turned on and the first switching tube and the second switching tube to be turned off when a first voltage across the first cell group and a second voltage across the second cell group are smaller than a discharge threshold value, so as to bypass the first cell group and the second cell group. In addition, the controller may further control each switching tube to re-connect the first and second battery cell groups to the battery cell clusters when the first and second voltages are not less than the discharge threshold. The battery pack in the energy storage system cuts out a battery cluster where the battery pack is located from a battery cell group with over-low voltage (namely unbalanced voltage) in the battery pack through the controller, and the battery cell group with normal voltage in the battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the battery pack is prevented from being cut out under the condition that the battery pack is provided with the normally working battery cell group, the control precision of the battery pack is higher, the utilization rate of the battery cell group is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a third possible implementation manner, the controller is configured to control the third switching tube and the fourth switching tube to be turned on and the first switching tube and the second switching tube to be turned off after the first voltage across the first cell group and the second voltage across the second cell group remain unchanged for a preset time, so as to bypass the first cell group and the second cell group. The battery pack in the energy storage system cuts out the battery cluster where the fault battery pack is located from the battery cell group with faults in the battery pack through the controller, and the battery cell group which normally works in the fault battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the situation that the normally working battery pack is cut out under the condition that the normally working battery pack is arranged in the fault battery pack is avoided, the control accuracy of the battery pack is higher, the utilization rate of the battery pack is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a fourth possible implementation manner, the controller is configured to control the second switching tube and the third switching tube to be turned on and the first switching tube and the fourth switching tube to be turned off when the first voltage is greater than a charging threshold and the second voltage is not greater than the charging threshold, so as to bypass the first cell group and access the second cell group. In addition, the controller may further control each switching tube (for example, control the first switching tube to be turned on and control the third switching tube to be turned off) to re-connect the first battery cell to the battery cluster when the first voltage is not greater than the charging threshold. The battery pack in the energy storage system cuts out a battery cluster where the battery pack is located from a first battery cell group with overhigh voltage in the battery pack through the controller, and a second battery cell group with normal voltage in the battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the battery pack is prevented from being cut out under the condition that the battery pack is provided with the normally working battery cell group, the control precision of the battery pack is higher, the utilization rate of the battery cell group is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a fifth possible implementation manner, the controller is configured to control the second switching tube and the third switching tube to be turned on and the first switching tube and the fourth switching tube to be turned off when the first voltage is less than a discharge threshold and the second voltage is not less than the discharge threshold, so as to bypass the first cell group and connect to the second cell group. In addition, the controller may further control each switching tube to re-connect the first battery cell to the battery cluster when the first voltage is not greater than the charging threshold. The battery pack in the energy storage system cuts out a battery cluster where the battery pack is located from a first battery cell group with too low voltage in the battery pack through the controller, and a second battery cell group with normal voltage in the battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the battery pack is prevented from being cut out under the condition that the battery pack is provided with the normally working battery cell group, the control precision of the battery pack is higher, the utilization rate of the battery cell group is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a sixth possible implementation manner, the controller is configured to control the second switching tube and the third switching tube to be turned on and the first switching tube and the fourth switching tube to be turned off after the first voltage across the first cell group is kept unchanged for a preset time, so as to bypass the first cell group and access the second cell group. The battery pack in the energy storage system cuts out a battery cluster where the fault battery pack is located from a first battery cell group with faults or unbalanced voltages in the battery pack through the controller, and a second battery cell group without faults in the fault battery pack is reserved to be connected into the battery cluster. The battery pack control method has the advantages that the situation that the normally working battery pack is cut out under the condition that the normally working battery pack is arranged in the fault battery pack is avoided, the control accuracy of the battery pack is higher, the utilization rate of the battery pack is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a seventh possible implementation manner, the controller is configured to control the first switching tube and the fourth switching tube to be turned on and the second switching tube and the third switching tube to be turned off when the second voltage is greater than a charging threshold and the first voltage is not greater than the charging threshold, so as to bypass the second cell group and access the first cell group. In addition, the controller may further control each switching tube (for example, control the second switching tube to be turned on and control the fourth switching tube to be turned off) to re-connect the second battery cell to the battery cluster when the second voltage is not greater than the charging threshold. The battery pack in the energy storage system cuts out a battery cluster where the battery pack is located from a second battery cell group with overhigh voltage in the battery pack through the controller, and the first battery cell group with normal voltage in the battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the battery pack is prevented from being cut out under the condition that the battery pack is provided with the normally working battery cell group, the control precision of the battery pack is higher, the utilization rate of the battery cell group is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in an eighth possible implementation manner, the controller is configured to control the first switching tube and the fourth switching tube to be turned on and the second switching tube and the third switching tube to be turned off when the second voltage is less than a discharge threshold and the first voltage is not less than the discharge threshold, so as to bypass the second cell group and access the first cell group. In addition, the controller may further control each switching tube to re-connect the second battery cell to the battery cluster when the second voltage is not greater than the charging threshold. And the battery pack in the energy storage system cuts out a battery cluster where the battery pack is located from a second battery cell group with too low voltage in the battery pack through the controller, and the first battery cell group with normal voltage in the battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the battery pack is prevented from being cut out under the condition that the battery pack is provided with the normally working battery cell group, the control precision of the battery pack is higher, the utilization rate of the battery cell group is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a ninth possible implementation manner, the controller is configured to control, after the second voltage across the second battery cell group is kept unchanged for a preset time, the first switch tube and the fourth switch tube to be turned on, and the second switch tube and the third switch tube to be turned off, so as to bypass the second battery cell group and access the first battery cell group. The battery pack in the energy storage system cuts out the battery cluster where the fault battery pack is located from the second battery cell group with faults or unbalanced voltages in the battery pack through the controller, and the first battery cell group without faults in the fault battery pack is reserved to be connected with the battery cluster. The battery pack control method has the advantages that the situation that the normally working battery pack is cut out under the condition that the normally working battery pack is arranged in the fault battery pack is avoided, the control accuracy of the battery pack is higher, the utilization rate of the battery pack is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to the first aspect, in a tenth possible implementation manner, the controller is configured to control, when each of the battery cell groups is charged and the first voltage across the first battery cell group and the second voltage across the second battery cell group are not greater than a charging threshold, or when each of the battery cell groups is discharged and the first voltage and the second voltage are not less than a discharging threshold, to turn on the first switching tube and the second switching tube and turn off the third switching tube and the fourth switching tube, so as to access the first battery cell group and the second battery cell group. When the battery cell groups in the battery pack work normally, the battery pack enables the first battery cell group and the second battery cell group to be connected into the battery cluster through the controller, so that the utilization rate of the battery cell groups is improved, and the charging and discharging efficiency of the energy storage system is higher.
With reference to any one of the first aspect to the tenth possible implementation manner of the first aspect, in an eleventh possible implementation manner, the battery pack further includes a fuse, a first fuse in the battery pack is connected between the first battery cell group and the third switching tube, and a second fuse in the battery pack is connected between the second battery cell group and the fourth switching tube. The first fuse and the second fuse are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed so as to prevent a switching tube in the battery pack from being damaged due to excessive current.
With reference to any one of the first aspect to the tenth possible implementation manner of the first aspect, in a twelfth possible implementation manner, the battery pack further includes a fuse, a first fuse is connected between the first cell group and the third switching tube, and a second fuse is connected between a connection end of the first switching tube and the second switching tube and a connection end of the third switching tube and the fourth switching tube. The first fuse and the second fuse are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed so as to prevent a switching tube in the battery pack from being damaged due to excessive current.
With reference to any one of the first aspect to the tenth possible implementation manner of the first aspect, in a thirteenth possible implementation manner, the battery pack further includes a fuse, a first fuse is connected between the first cell group and the third switching tube, and a second fuse is connected between the first switching tube and the third switching tube. The first fuse and the second fuse are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed so as to prevent a switching tube in the battery pack from being damaged due to excessive current.
With reference to any one of the first aspect to the tenth possible implementation manner of the first aspect, in a fourteenth possible implementation manner, the battery pack further includes a fuse, the first fuse is connected between a connection end of the first switching tube and the second switching tube and a connection end of the third switching tube and the fourth switching tube, and the second fuse is connected between the second cell group and the fourth switching tube. The first fuse and the second fuse are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed so as to prevent a switching tube in the battery pack from being damaged due to excessive current.
With reference to any one of the first aspect to the tenth possible implementation manner of the first aspect, in a fifteenth possible implementation manner, the battery pack further includes a fuse, the first fuse is connected between the connection ends of the second switching tube and the fourth switching tube, and the second fuse is connected between the second cell group and the fourth switching tube. The first fuse and the second fuse are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed so as to prevent a switching tube in the battery pack from being damaged due to excessive current.
Drawings
FIG. 1 is a schematic diagram of an application scenario of an energy storage system provided by the present application;
FIG. 2 is a schematic diagram of an energy storage system according to the present application;
FIG. 3 is a schematic view of a battery pack according to the present application;
FIG. 4a is a schematic diagram of a control structure of a switching tube of a battery pack according to the present application;
fig. 4b is another schematic structural diagram of the control of the switching tube of the battery pack according to the present application;
Fig. 4c is another schematic structural diagram of a battery pack switching tube control provided by the present application;
Fig. 4d is another schematic structural diagram of the control of the switching tube of the battery pack according to the present application;
fig. 5a is another schematic structural view of a battery pack according to the present application;
fig. 5b is another schematic structural view of the battery pack provided by the present application;
fig. 5c is another schematic structural view of the battery pack provided by the present application;
fig. 5d is another schematic structural view of the battery pack according to the present application.
Detailed Description
Referring to fig. 1, fig. 1 is a schematic diagram of an application scenario of an energy storage system provided by the present application. In the energy storage system provided by the application, a plurality of battery clusters (for example, a battery cluster a and a battery cluster b) can be included, each battery cluster can include a plurality of battery packs connected in series (for example, the battery cluster a includes a battery pack 11, a battery pack 12, … … and a battery pack 1n connected in series, the battery cluster b includes a battery pack 21, a battery pack 22, … … and a battery pack 2n connected in series), and the plurality of battery packs connected in series are connected to a battery cluster bus and coupled with a Direct Current (DC)/DC converter (the battery pack in the battery cluster a is coupled with the DC/DC converter a, and the battery pack in the battery cluster b is coupled with the DC/DC converter b). Here, the DC/DC converter may be a bidirectional DC/DC converter, and the circuit topology of the bidirectional DC/DC converter (including the converter DC/DC1 and the converter DC/DC 2) may be selected from a boost circuit (boostcircuit), a flying capacitor boost circuit (boostcircuit boost circuit), a flying capacitor multi-level circuit (flying capacitor multilevel circuit), a positive-negative symmetrical three-level boost circuit (wire-level boost circuit), a four-pipe boost circuit (four-switch buck-boost circuit), and the like, which may be specifically determined according to the actual application scene requirements, and is not limited herein. The DC/DC converter may perform voltage conversion (e.g., voltage boosting or voltage reducing) on a direct current (e.g., a direct current output from each battery pack) output from a battery pack in the energy storage system, and output the direct current after the voltage conversion to a direct current load for supplying power to the direct current load, where the direct current load may be a factory park, a charging station including a charging pile, or the like.
In some possible embodiments, referring again to fig. 1, the energy storage system may further comprise a DC/AC converter coupled to a DC terminal of the DC/AC converter, the AC terminal of the DC/AC converter being coupled to an AC load. The DC/DC converter can perform voltage conversion on direct current output by the battery cluster in the energy storage system, the DC/AC converter can perform inversion conversion on the direct current output by the DC/DC converter, and alternating current obtained after inversion conversion is output to an alternating current load to supply power to the direct current load, wherein the alternating current load can be electric equipment such as a communication base station or household equipment.
In some possible embodiments, referring again to fig. 1, the energy storage system further includes a DC power source, where the DC power source may be composed of a photovoltaic array, and an output end of the photovoltaic array may be connected to one end of the DC/DC converter (may include a DC/DC converter a and a DC/DC converter b). In the energy storage system shown in fig. 1, the photovoltaic array may be formed by connecting one or more photovoltaic strings in parallel, and one photovoltaic string may be formed by connecting one or more photovoltaic modules in series. Optionally, the dc power supply may further include an ac power grid and a rectifier (not shown in fig. 1), where the rectifier may rectify and transform ac power output from the ac power grid to obtain dc power. The DC/DC converter may perform voltage conversion (may be voltage boosting, voltage reducing, etc.) on the DC power supplied from the photovoltaic array or the ac power grid and the rectifier, and supply the DC power after the voltage conversion to the battery packs in the battery cluster to supply power to the respective battery packs (the DC/DC converter a charges the battery packs in the battery cluster a based on the DC power of the photovoltaic array, and the DC/DC converter b charges the battery packs in the battery cluster b based on the DC power of the photovoltaic array).
In some possible embodiments, in the energy storage system, each battery pack in each battery cluster may include a plurality of battery cell groups (not shown in fig. 1) connected in series, where the battery cell groups may be formed by connecting a plurality of unit battery cells in series and parallel, typically 10 to 20 unit battery cells are directly connected in series, and the unit battery cells may be a lithium ion battery, a lead acid battery, or the like, and may be determined according to a specific device type, and are not limited herein. In the working process (in the charging or discharging process) of the energy storage system, the battery pack in the battery cluster can have battery pack faults or unbalanced voltages, wherein the battery pack faults or unbalanced voltages can be caused by the fact that part of the battery cell groups in the battery pack cannot work normally, for example, the battery pack faults are caused by the fact that the voltages of the part of the battery cell groups in the battery pack remain unchanged in the charging or discharging process of the battery cluster, and the battery pack voltages are unbalanced due to the fact that the voltages of the part of the battery cell groups in the battery pack are too high or too low in the charging and discharging process of the battery cluster. In the current battery energy storage system, when a battery pack fails, the whole battery pack is generally cut off to avoid influencing charge and discharge of a battery cluster, and in addition, an effective solution is not available when a battery cell group is unbalanced. However, when the battery pack fails because part of the battery cell groups in the battery pack cannot work normally, the battery cell groups in the failure battery pack still work normally, the battery cell group utilization rate is low due to the mode of cutting off the whole battery pack, the control precision of the battery pack is low, and the charge and discharge efficiency of the energy storage system is also reduced due to unbalance of the battery cell groups.
In the energy storage system provided by the application, the energy storage system can comprise a plurality of battery clusters, the battery clusters are respectively coupled with a direct current power supply and a load through a direct current bus, the battery clusters can comprise a plurality of battery packs connected in series, wherein the battery packs can comprise a controller, two battery cell groups (which can be called a first battery cell group and a second battery cell group for convenience of description) and a plurality of switching tubes. Here, the negative electrode of the first cell group may be connected to the positive electrode of the second cell group through a first switching tube and a second switching tube connected in series, the positive electrode of the first cell group may be connected to the negative electrode of the second cell group through a third switching tube and a fourth switching tube connected in series, and the connection ends of the first switching tube and the second switching tube may be connected to the connection ends of the third switching tube and the fourth switching tube. In the working process of the energy storage system, the first battery cell group and the second battery cell group can be charged based on the power supply of the direct current power supply or power is supplied to a load through a direct current bus, the controller can detect whether each battery cell group has faults (for example, the voltage is unchanged in the charging and discharging processes of the battery cell group) or has unbalanced voltages (for example, the voltage is overhigh in the charging processes of the battery cell group and the voltage is overlow in the discharging processes of the battery cell group) based on the voltages at the two ends of the first battery cell group and the second battery cell group, and when the faults or the unbalanced voltages of the battery cell group are detected, each switch tube (comprising the first switch tube, the second switch tube, the third switch tube and the fourth switch tube) in the battery pack is controlled to be turned on or off so as to access or bypass any battery cell group in the battery pack. And cutting out the battery cluster where the battery pack is located by the battery cell group (all or part of the battery cell groups in the battery pack) with faults or unbalanced voltages in the battery pack through the controller, and reserving the battery cell group which is connected into the battery pack and works normally. For example, when the first cell group in the battery pack fails or the voltage is unbalanced, and the second cell group works normally, the controller can control each switch tube to bypass the first cell group in the battery pack so as to cut out the battery cluster where the failed battery pack is located, and to connect the second cell group into the battery cluster so as to continue charging and discharging, so that the situation that the normally working cell group is cut out under the condition that the normally working cell group exists in the failed battery pack is avoided, the control precision of the battery pack is higher, the utilization rate of the cell group is improved, and the charging and discharging efficiency of the energy storage system is higher.
Referring to fig. 2, fig. 2 is a schematic structural diagram of an energy storage system according to the present application. In the energy storage system shown in fig. 2, a plurality of battery clusters (e.g., battery cluster a and battery cluster b) are included, each of which may include a plurality of battery packs connected in series (e.g., battery cluster a includes battery pack 11, battery packs 12, … …, battery pack 1n connected in series, battery cluster b includes battery pack 21, battery packs 22, … …, battery pack 2n connected in series) connected to a battery cluster bus and coupled to a DC/DC converter (the battery packs in battery cluster a are coupled to DC/DC converter a, and the battery packs in battery cluster b are coupled to DC/DC converter b). The DC/DC converter may perform voltage conversion (e.g., voltage boosting or voltage reducing) on a direct current (e.g., a direct current output from each battery pack) output from a battery pack in the energy storage system, and output the direct current after voltage conversion to a direct current load to supply power to the direct current load (e.g., a factory park, a charging station including a charging pile, etc.). The energy storage system of fig. 2 may further comprise a DC/AC converter coupled to a DC terminal of the DC/AC converter, an AC terminal of the DC/AC converter being coupled to an AC load. The DC/DC converter can perform voltage conversion on direct current output by the battery cluster in the energy storage system, the DC/AC converter can perform inversion conversion on the direct current output by the DC/DC converter, and alternating current obtained after inversion conversion is output to an alternating current load to supply power to the direct current load, wherein the alternating current load can be electric equipment such as a communication base station or household equipment.
In some possible embodiments, the energy storage system in fig. 2 further includes a DC power source, where the battery cluster a may be coupled to an output of the DC power source through a DC/DC converter a, and the battery cluster b may be coupled to an output of the DC power source through a DC/DC converter b, where the DC/DC converter may perform voltage conversion (such as voltage boosting, voltage dropping, etc.) on the DC power provided by the DC power source, and provide the DC power after the voltage conversion to the battery packs in the battery cluster to power the respective battery packs.
In some possible embodiments, in the energy storage system shown in fig. 2, each battery pack in the battery cluster may include a controller, two battery cell groups (which may be referred to as a first battery cell group and a second battery cell group for convenience of description), and a plurality of switching tubes. Taking the battery pack 11 in the battery cluster a as an example, the battery pack 11 may include a first battery cell group (for convenience of description, may be denoted as the battery cell group 1), a second battery cell group (for convenience of description, may be denoted as the battery cell group 2), a first switching tube (for convenience of description, may be denoted as the switching tube S1), a second switching tube (for convenience of description, may be denoted as the switching tube S2), a third switching tube (for convenience of description, may be denoted as the switching tube S3), and a fourth switching tube (for convenience of description, may be denoted as the switching tube S4). The negative electrode of the battery cell group 1 can be connected with the positive electrode of the battery cell group 2 through a switch tube S1 and a switch tube S2 which are connected in series, the positive electrode of the battery cell group 1 can be connected with the negative electrode of the battery cell group 2 through a switch tube S3 and a switch tube S4 which are connected in series, and the connecting end of the switch tube S1 and the switch tube S2 can be connected with the connecting end of the switch tube S3 and the switch tube S4. The battery pack 11 may further include a controller (not shown in fig. 2), which may detect whether each of the battery packs has a fault (for example, the voltage is unchanged during charging and discharging of the battery pack) or a voltage imbalance (for example, the voltage is too high during charging of the battery pack, the voltage is too low during discharging of the battery pack, etc.) based on the voltages at the two ends of the battery pack 1 and the battery pack 2, and control each of the switching tubes (including the switching tube S1, the switching tube S2, the switching tube S3, and the switching tube S4) in the battery pack to be turned on or off when the fault or the voltage imbalance of the battery pack is detected, so as to access or bypass any one of the battery packs 11. For example, during the charging process of each cell group in the battery pack 11, when the controller detects that the voltage across the cell group 1 is too high (may be greater than the charging threshold), the switch tube S2 and the switch tube S3 are controlled to be turned on, and the switch tube S1 and the switch tube S4 are controlled to be turned off, so as to bypass the cell group 1 and access the cell group 2 (cut the cell group 1 from the battery cluster a and access the cell group 2 to the battery cluster a). It will be appreciated that the composition of the other battery packs and the process of controlling the switching tubes to bypass the respective battery cell groups in fig. 2 may refer to the above description of the battery pack 11, and will not be repeated here. When the battery pack fails in the energy storage system, the battery clusters where the failed battery pack is located are cut out by the battery cell group (all or part of the battery cell groups in the battery pack) with the failure or unbalanced voltage in the battery pack through the controller, and the battery cell groups which normally work in the failed battery pack are reserved to be assembled into the battery clusters. The battery pack control method has the advantages that the situation that the normally working battery pack is cut out under the condition that the normally working battery pack is arranged in the fault battery pack is avoided, the control accuracy of the battery pack is higher, the utilization rate of the battery pack is improved, and the charging and discharging efficiency of the energy storage system is higher.
An energy storage system according to an embodiment of the present application will be illustrated with reference to fig. 3 to 5 d. In some possible embodiments, referring to fig. 3, fig. 3 is a schematic structural diagram of a battery pack provided in the present application, and the battery pack shown in fig. 3 may be any battery pack in any battery cluster in the energy storage system, for example, any one of the battery packs 11 to 1n and 21 to 2 n. For convenience of description, the battery pack will be directly exemplified as follows. The battery pack in fig. 3 includes a first cell group (may be denoted as a cell group 1 for convenience of description), a second cell group (may be denoted as a cell group 2 for convenience of description), a first switching tube (may be denoted as a switching tube S1 for convenience of description), a second switching tube (may be denoted as a switching tube S2 for convenience of description), a third switching tube (may be denoted as a switching tube S3 for convenience of description), and a fourth switching tube (may be denoted as a switching tube S4 for convenience of description). Here, each switching tube may be a Metal-Oxide-semiconductor field effect transistor (MOSFET), abbreviated as a MOS tube, or may be an insulated gate bipolar transistor (insulated gate bipolar transistor, IGBT), etc., which may be specifically determined according to an actual application scenario, and is not limited herein. The battery pack in fig. 3 is illustrated by taking each switching tube as an MOS tube, wherein the drain electrode of the switching tube S1 is connected to the negative electrode of the cell group 1, the source electrode of the switching tube S1 is connected to the drain electrode of the switching tube S2, and the source electrode of the switching tube S2 is connected to the positive electrode of the cell group 2. The positive electrode of the battery cell group 1 is used as a first input/output end of the battery pack to be connected with the source electrode of the switch tube S3, the negative electrode of the battery cell group 2 is used as a second input/output end of the battery pack to be connected with the drain electrode of the switch tube S4, and the drain electrode of the switch tube S3 is connected with the source electrode of the switch tube S4. When the energy storage system charges the battery pack in fig. 3, the first input/output end of the battery pack is the input end of the battery pack, and the second input/output end of the battery pack is the output end of the battery pack. When the battery pack discharges, the first input/output end of the battery pack is the output end of the battery pack, and the second input/output end of the battery pack is the input end of the battery pack. The input/output end of the battery pack is used as an input end or an output end, and can be specifically determined according to practical application scenes, and the battery pack is not limited herein. The battery pack may further include a controller, where the controller may be a battery management unit (Battery Management Unit, BMU), and the BMU may send a driving signal (such as a pulse width modulation (Pulse Width Modulation, PWM) signal) to the switching tubes in the battery pack, where the driving signal may be from a centralized monitoring system in a battery cluster where the battery pack is located, and each switching tube may be turned on or off based on the received driving signal. When the battery pack fails, the battery cell group (all or part of the battery cell groups in the battery pack) with failure or unbalanced voltage in the battery pack is cut out of the battery cluster where the failed battery pack is located through the BMU, and the battery cell group which normally works in the failed battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the situation that the normally working battery pack is cut out under the condition that the normally working battery pack is arranged in the fault battery pack is avoided, the control accuracy of the battery pack is higher, the utilization rate of the battery pack is improved, and the charging and discharging efficiency of the energy storage system is higher.
In some possible embodiments, each battery pack in the energy storage system further includes a Fuse, please refer to fig. 3 again, the battery pack in fig. 3 includes a first Fuse (for convenience of description, may be denoted as Fuse 1) and a second Fuse (for convenience of description, may be denoted as Fuse 2), the Fuse1 may be connected between the battery cell group 1 and the switch tube S3 (specifically, one end of the Fuse1 is connected with the positive electrode of the battery cell group 1, the other end of the Fuse1 is connected with the source electrode of the switch tube S3), the Fuse2 can be connected between the battery cell group 2 and the switch tube S4 (specifically, one end of the Fuse2 is connected with the negative electrode of the battery cell group 2, and the other end of the Fuse2 is connected with the drain electrode of the switch tube S4). The Fuse1 and the Fuse2 are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed, so as to prevent damage to a switching tube in the battery pack due to excessive current. Further, the controller (may be a BMU) in the battery pack may detect whether each of the battery packs has a fault (for example, the voltage is unchanged during charging and discharging of the battery pack) or a voltage imbalance (for example, the voltage is too high during charging of the battery pack, the voltage is too low during discharging of the battery pack, etc.) based on the voltages at the two ends of the battery pack 1 and the battery pack 2, and control each of the switching tubes (including the switching tube S1, the switching tube S2, the switching tube S3, and the switching tube S4) in the battery pack to be turned on or off when the fault or the voltage imbalance of the battery pack is detected, so as to access or bypass any one of the battery packs. Specifically, the controller may control the switching tube S3 and the switching tube S4 to be turned on and the switching tube S1 and the switching tube S2 to be turned off when the voltages (which may be referred to as the first voltages for convenience of description) at both ends of the battery cell group 1 and the voltages (which may be referred to as the second voltages for convenience of description) at both ends of the battery cell group 2 are greater than the charging threshold value in the charging process of the battery cell group 1 and the battery cell group 2 (which may be based on the direct current supplied by the DC/DC converter a or the DC/DC converter b). Referring to fig. 4a, fig. 4a is a schematic structural diagram of a control of a switch tube of a battery pack according to the present application, as shown in fig. 4a, a controller controls the switch tube S3 and the switch tube S4 to be turned on, and controls the switch tube S1 and the switch tube S2 to be turned off, so that the battery cell group 1 and the battery cell group 2 are bypassed, and charging current in the battery pack flows from the Fuse1 to the Fuse2, so as to avoid that excessively high voltages at two ends of the battery cell group 1 and the battery cell group 2 trigger overvoltage protection of an energy storage system (such as cutting out the whole battery cluster), and affect charging efficiency of the energy storage system. Optionally, the controller may control the switch tube S3 and the switch tube S4 to be turned on and the switch tube S1 and the switch tube S2 to be turned off when the first voltage and the second voltage are greater than the discharge threshold in the discharging process of the battery cell group 1 and the battery cell group 2, so as to bypass the battery cell group 1 and the battery cell group 2, and avoid that the voltages at two ends of the battery cell group 1 and the battery cell group 2 are too low to trigger the under-voltage protection of the energy storage system, thereby affecting the charging efficiency of the energy storage system. Optionally, the controller may control the switch tube S3 and the switch tube S4 to be turned on and the switch tube S1 and the switch tube S2 to be turned off after the first voltage and the second voltage remain unchanged and remain for a preset time in the charging or discharging process of the battery cell group 1 and the battery cell group 2, that is, when the battery cell group 1 and the battery cell group 2 cannot be charged or discharged normally. The charging threshold may be obtained by adding an additional voltage (e.g., 0.5 v) to an average voltage of a battery pack in the energy storage system (may be an average voltage of a battery cell group in the battery pack) during charging of the energy storage system, and the discharging threshold may be obtained by subtracting an additional voltage (e.g., 0.5 v) from an average voltage of a battery pack in the energy storage system (may be an average voltage of a battery cell group in the battery pack) during discharging of the energy storage system. Here, the charge threshold is greater than the discharge threshold. The battery pack in the energy storage system cuts out the battery cluster where the fault battery pack is located from the battery cell group with faults or unbalanced voltages in the battery pack through the controller, and the battery cell group which normally works in the fault battery pack is reserved to be assembled into the battery cluster. The battery pack control method has the advantages that the situation that the normally working battery pack is cut out under the condition that the normally working battery pack is arranged in the fault battery pack is avoided, the control accuracy of the battery pack is higher, the utilization rate of the battery pack is improved, and the charging and discharging efficiency of the energy storage system is higher.
In some possible embodiments, the controller in the battery pack may control the switch tube S2 and the switch tube S3 to be turned on and the switch tube S1 and the switch tube S4 to be turned off when the first voltage is greater than the charging threshold and the second voltage is not greater than the charging threshold during the charging process of the battery cell group 1 and the battery cell group 2 (may be based on the direct current provided by the DC/DC converter a or the DC/DC converter b), so as to bypass the battery cell group 1 and access the battery cell group 2. Referring to fig. 4b, fig. 4b is another schematic diagram of the control structure of the switch tube of the battery pack provided by the present application, as shown in fig. 4b, the controller controls the switch tube S2 and the switch tube S3 to be turned on, and controls the switch tube S1 and the switch tube S4 to be turned off, so that the battery cell group 1 is bypassed and connected to the battery cell group 2, and the charging current in the battery pack flows from the Fuse1 to the battery cell group 2, so as to avoid the excessively high voltage at two ends of the battery cell group 1 from triggering the overvoltage protection of the energy storage system, and to influence the charging efficiency of the energy storage system. Optionally, the controller may control the switch tube S2 and the switch tube S3 to be turned on and the switch tube S1 and the switch tube S4 to be turned off when the first voltage is less than a discharge threshold and the second voltage is not less than the discharge threshold in a discharge process of the battery cell group 1 and the battery cell group 2, so as to bypass the battery cell group 1 and access the battery cell group 2, and avoid that the voltage at two ends of the battery cell group 1 is too low to trigger an under-voltage protection of the energy storage system, thereby affecting a charging efficiency of the energy storage system. Optionally, the controller may control the switch tube S2 and the switch tube S3 to be turned on and the switch tube S1 and the switch tube S4 to be turned off after the first voltage is kept unchanged and the first voltage is kept for a preset time in the charging or discharging process of the battery cell group 1 and the battery cell group 2, that is, when the battery cell group 1 cannot be charged or discharged normally. The battery pack in the energy storage system cuts out a battery cluster where the fault battery pack is located from the battery cell group 1 with faults or unbalanced voltages in the battery pack through the controller, and the battery cell group 2 which keeps normal working in the fault battery pack is connected into the battery cluster. The battery pack control method has the advantages that the situation that the normally working battery pack is cut out under the condition that the normally working battery pack is arranged in the fault battery pack is avoided, the control accuracy of the battery pack is higher, the utilization rate of the battery pack is improved, and the charging and discharging efficiency of the energy storage system is higher.
In some possible embodiments, the controller in the battery pack may control the switch tube S1 and the switch tube S4 to be turned on and the switch tube S2 and the switch tube S3 to be turned off when the second voltage is greater than the charging threshold and the first voltage is not greater than the charging threshold during the charging process of the battery cell group 1 and the battery cell group 2 (may be based on the direct current provided by the DC/DC converter a or the DC/DC converter b), so as to bypass the battery cell group 2 and access the battery cell group 1. Referring to fig. 4c, fig. 4c is another schematic diagram of the control structure of the switch tube of the battery pack provided by the present application, as shown in fig. 4c, the controller controls the switch tube S1 and the switch tube S4 to be turned on, and controls the switch tube S2 and the switch tube S3 to be turned off, so that the battery cell group 2 is bypassed and connected to the battery cell group 1, and the charging current in the battery pack flows from the battery cell group 1 to the Fuse2, so as to avoid the excessively high voltage at two ends of the battery cell group 2 from triggering the overvoltage protection of the energy storage system, and to influence the charging efficiency of the energy storage system. Optionally, the controller may control the switch tube S1 and the switch tube S4 to be turned on and the switch tube S2 and the switch tube S3 to be turned off when the second voltage is less than a discharge threshold and the first voltage is not less than the discharge threshold in a discharge process of the battery cell group 1 and the battery cell group 2, so as to bypass the battery cell group 2 and access the battery cell group 1, thereby avoiding that the voltage at two ends of the battery cell group 2 is too low to trigger an under-voltage protection of the energy storage system and affect a charging efficiency of the energy storage system. Optionally, the controller may control the switch tube S1 and the switch tube S4 to be turned on and the switch tube S2 and the switch tube S3 to be turned off after the second voltage is kept unchanged and the second voltage is kept for a preset time in the charging or discharging process of the battery cell group 1 and the battery cell group 2, that is, when the battery cell group 2 cannot be charged or discharged normally. The battery pack in the energy storage system cuts out a battery cluster where the fault battery pack is located from the battery cell group 2 with faults or unbalanced voltages in the battery pack through the controller, and the battery cell group 1 which keeps normal working in the fault battery pack is accessed into the battery cluster. The battery pack control method has the advantages that the situation that the normally working battery pack is cut out under the condition that the normally working battery pack is arranged in the fault battery pack is avoided, the control accuracy of the battery pack is higher, the utilization rate of the battery pack is improved, and the charging and discharging efficiency of the energy storage system is higher.
In some possible embodiments, the controller in the battery pack may control the switch tube S1 and the switch tube S2 to be turned on and the switch tube S3 and the switch tube S4 to be turned off when the first voltage and the second voltage are not greater than the charging threshold value during the charging process of the battery cell group 1 and the battery cell group 2 (may be the charging process based on the direct current provided by the DC/DC converter a or the DC/DC converter b), so as to access the battery cell group 1 and the battery cell group 2. Referring to fig. 4d together, fig. 4d is another schematic diagram of the control structure of the switch tube of the battery pack provided by the present application, as shown in fig. 4d, the controller controls the switch tube S1 and the switch tube S2 to be turned on, and controls the switch tube S3 and the switch tube S4 to be turned off, so as to access the battery cell group 1 and the battery cell group 2, and the charging current in the battery pack flows from the battery cell group 1 to the battery cell group 2. Optionally, the controller may control the switch tube S1 and the switch tube S2 to be turned on and the switch tube S3 and the switch tube S4 to be turned off when the first voltage and the second voltage are not less than the discharge threshold in the discharging process of the battery cell group 1 and the battery cell group 2, so as to access the battery cell group 1 and the battery cell group 2. When the battery cell group in the battery pack works normally, the battery pack enables the battery cell group 1 and the battery cell group 2 to be connected into a battery cluster through the controller, so that the utilization rate of the battery cell group is improved, and the charge and discharge efficiency of the energy storage system is higher.
In some possible embodiments, a first fuse in a battery pack (e.g., the battery pack shown in fig. 3 above) may be connected between the first cell stack and the third switching tube, and a second fuse may be connected between the connection ends of the first and second switching tubes and the connection ends of the third and fourth switching tubes. Referring to fig. 5a, fig. 5a is another schematic structural diagram of the battery pack provided by the present application, as shown in fig. 5a, one end of the Fuse1 is connected to the positive electrode of the battery cell group 1, and the other end of the Fuse1 is connected to the source electrode of the switching tube S3. One end of the Fuse2 is connected with the connecting ends of the switching tube S1 and the switching tube S2, and the other end of the Fuse2 is connected with the connecting ends of the switching tube S3 and the switching tube S4. The Fuse1 and the Fuse2 are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed, so as to prevent damage to a switching tube in the battery pack due to excessive current. For example, fuse1 and Fuse2 may over-current protect switching tube S3 when cell stack 1 is bypassed, fuse2 may over-current protect switching tube S4 when cell stack 2 is bypassed, and Fuse1 may over-current protect switching tube S3 and switching tube S4 when both cell stack 1 and cell stack 2 are bypassed.
In some possible embodiments, a first fuse in a battery pack (e.g., the battery pack shown in fig. 3 above) may be connected between the first cell stack and the third switching tube, and a second fuse may be connected between the first switching tube and the third switching tube. Referring to fig. 5b, fig. 5b is another schematic structural diagram of the battery pack provided by the present application, as shown in fig. 5b, one end of the Fuse1 is connected to the positive electrode of the battery cell group 1, and the other end of the Fuse1 is connected to the source electrode of the switching tube S3. One end of the Fuse2 is connected with the source electrode of the switching tube S1, and the other end of the Fuse2 is connected with the drain electrode of the switching tube S2, the drain electrode of the switching tube S3 and the source electrode of the switching tube S4. The Fuse1 and the Fuse2 are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed, so as to prevent damage to a switching tube in the battery pack due to excessive current. For example, fuse1 may over-current protect switching tube S3 when cell stack 1 is bypassed, fuse2 may over-current protect switching tube S4 when cell stack 2 is bypassed, and Fuse1 may over-current protect switching tube S3 and switching tube S4 when both cell stack 1 and cell stack 2 are bypassed.
In some possible embodiments, a first fuse in a battery pack (e.g., the battery pack shown in fig. 3) may be connected between the connection ends of the first and second switching tubes and the connection ends of the third and fourth switching tubes, and a second fuse may be connected between the second and fourth switching tubes. Referring to fig. 5c, fig. 5c is another schematic structural diagram of the battery pack provided by the present application, as shown in fig. 5c, one end of the Fuse1 is connected to the connection end of the switching tube S1 and the switching tube S2, and the other end of the Fuse1 is connected to the connection end of the switching tube S3 and the switching tube S4. One end of the Fuse2 is connected with the negative electrode of the battery cell group 2, and the other end of the Fuse2 is connected with the drain electrode of the switching tube S4. The Fuse1 and the Fuse2 are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed, so as to prevent damage to a switching tube in the battery pack due to excessive current. For example, fuse1 may over-current protect switching tube S3 when cell stack 1 is bypassed, fuse1 and Fuse2 may over-current protect switching tube S4 when cell stack 2 is bypassed, and Fuse2 may over-current protect switching tube S3 and switching tube S4 when both cell stack 1 and cell stack 2 are bypassed.
In some possible embodiments, a first fuse in a battery pack (e.g., the battery pack shown in fig. 3 above) may be connected between the connection ends of the second switching tube and the fourth switching tube, and a second fuse may be connected between the second cell stack and the fourth switching tube. Referring to fig. 5d, fig. 5d is another schematic diagram of the battery pack according to the present application, as shown in fig. 5d, one end of the Fuse1 is connected to the drain of the switching tube S2, and the other end of the Fuse1 is connected to the source of the switching tube S1, the drain of the switching tube S3, and the source of the switching tube S4. The Fuse1 and the Fuse2 are used for performing overcurrent protection on a circuit in the battery pack when at least one cell group in the battery pack is bypassed, so as to prevent damage to a switching tube in the battery pack due to excessive current. For example, fuse1 may over-current protect switching tube S3 when cell stack 1 is bypassed, fuse2 may over-current protect switching tube S4 when cell stack 2 is bypassed, and Fuse2 may over-current protect switching tube S3 and switching tube S4 when both cell stack 1 and cell stack 2 are bypassed.
In the application, in the working process of the energy storage system, the first cell group and the second cell group of each battery pack in the energy storage system can be charged based on the power supply of a direct current power supply or power is supplied to a load through a direct current bus, each battery pack can detect whether each cell group has faults (for example, the voltage is unchanged in the charging and discharging processes of the cell group) or has unbalanced voltages (for example, the voltage is too high in the charging process of the cell group and the voltage is too low in the discharging process of the cell group) based on the voltages at two ends of the first cell group and the second cell group through a controller, and when the faults or the unbalanced voltages of the cell groups are detected, each switch tube (comprising the first switch tube, the second switch tube, the third switch tube and the fourth switch tube) in the battery pack is controlled to be turned on or off so as to be connected with or bypass any one of the cell groups. The energy storage system cuts out a battery cluster where a fault battery pack is located through a battery pack of the battery pack (all or part of battery packs in the battery pack) with faults or unbalanced voltage by the controller, and reserves the battery pack which is connected into the fault battery pack and works normally, so that the battery pack control precision is higher, the utilization rate of the battery pack is improved, and the charge and discharge efficiency of the energy storage system is higher. In addition, each battery pack in the energy storage system further comprises a fuse, and the fuse can carry out overcurrent protection on a circuit in the battery pack when at least one battery cell group in the battery pack is bypassed so as to prevent a switching tube in the battery pack from being damaged due to excessive current.

Claims (16)

1. The battery pack is characterized by comprising a controller, a first battery cell group, a second battery cell group and a plurality of switch tubes, wherein the negative electrode of the first battery cell group is connected with the positive electrode of the second battery cell group through a first switch tube and a second switch tube which are connected in series, the positive electrode of the first battery cell group is connected with the negative electrode of the second battery cell group through a third switch tube and a fourth switch tube which are connected in series, the connecting ends of the first switch tube and the second switch tube are connected with the connecting ends of the third switch tube and the fourth switch tube, the positive electrode of the first battery cell group is used as a first input/output end of the battery pack, and the negative electrode of the second battery cell group is used as a second input/output end of the battery pack;
The controller is used for controlling the switching-on or switching-off of each switching tube based on the voltages at two ends of the first battery cell group and the second battery cell group so as to access or bypass any battery cell group in the battery pack.
2. The battery pack of claim 1, wherein the controller is configured to control the third and fourth switching tubes to be on and the first and second switching tubes to be off to bypass the first and second cell groups when a first voltage across the first cell group and a second voltage across the second cell group are greater than a charge threshold.
3. The battery pack of claim 1, wherein the controller is configured to control the third and fourth switching tubes to be on and the first and second switching tubes to be off to bypass the first and second cell groups when a first voltage across the first cell group and a second voltage across the second cell group are less than a discharge threshold.
4. The battery pack of claim 1, wherein the controller is configured to control the third and fourth switching tubes to be turned on and the first and second switching tubes to be turned off to bypass the first and second cell groups after a first voltage across the first cell group and a second voltage across the second cell group remain unchanged for a preset time.
5. The battery pack of claim 1, wherein the controller is configured to control the second and third switching tubes to be on and the first and fourth switching tubes to be off to bypass the first cell group and to access the second cell group when the first voltage is greater than a charge threshold and the second voltage is not greater than the charge threshold.
6. The battery pack of claim 1, wherein the controller is configured to control the second and third switching tubes to be on and the first and fourth switching tubes to be off to bypass the first cell group and to access the second cell group when the first voltage is less than a discharge threshold and the second voltage is not less than the discharge threshold.
7. The battery pack of claim 1, wherein the controller is configured to control the second and third switching tubes to be turned on and the first and fourth switching tubes to be turned off after the first voltage across the first cell group is maintained for a preset time to bypass the first cell group and access the second cell group.
8. The battery pack of claim 1, wherein the controller is configured to control the first and fourth switching tubes to be on and the second and third switching tubes to be off to bypass the second cell group and access the first cell group when the second voltage is greater than a charge threshold and the first voltage is not greater than the charge threshold.
9. The battery pack of claim 1, wherein the controller is configured to control the first and fourth switching tubes to be on and the second and third switching tubes to be off to bypass the second cell group and to access the first cell group when the second voltage is less than a discharge threshold and the first voltage is not less than the discharge threshold.
10. The battery pack of claim 1, wherein the controller is configured to control the first switching tube and the fourth switching tube to be turned on and the second switching tube and the third switching tube to be turned off after the second voltage across the second cell group is maintained for a preset time to bypass the second cell group and access the first cell group.
11. The battery pack of claim 1, wherein the controller is configured to control the first and second switching tubes to be turned on and the third and fourth switching tubes to be turned off to access the first and second cell groups when each cell group is charged and a first voltage across the first cell group and a second voltage across the second cell group are not greater than a charge threshold, or when each cell group is discharged and the first and second voltages are not less than a discharge threshold.
12. The battery pack of any one of claims 1-11, further comprising a fuse, a first fuse in the battery pack connected between the first cell stack and the third switching tube, and a second fuse in the battery pack connected between the second cell stack and the fourth switching tube.
13. The battery pack of any one of claims 1-11, further comprising a fuse, a first fuse connected between the first cell stack and the third switching tube, and a second fuse connected between the connection ends of the first switching tube and the second switching tube and the connection ends of the third switching tube and the fourth switching tube.
14. The battery pack of any one of claims 1-11, further comprising a fuse, a first fuse connected between the first cell stack and the third switching tube, and a second fuse connected between the first switching tube and the third switching tube.
15. The battery pack of any one of claims 1-11, further comprising a fuse, a first fuse connected between the connection ends of the first and second switching tubes and the connection ends of the third and fourth switching tubes, a second fuse connected between the second cell stack and the fourth switching tube.
16. The battery pack of any one of claims 1-11, further comprising a fuse, a first fuse connected between the connection ends of the second and fourth switching tubes, and a second fuse connected between the second cell stack and the fourth switching tube.
CN202310963711.8A 2023-01-18 2023-01-18 Battery pack Pending CN117977501A (en)

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CN202310963711.8A CN117977501A (en) 2023-01-18 2023-01-18 Battery pack

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