WO2024108401A1 - Procédé de connexion en parallèle de blocs-batteries, système de gestion de batteries, bloc-batterie et dispositif électrique - Google Patents

Procédé de connexion en parallèle de blocs-batteries, système de gestion de batteries, bloc-batterie et dispositif électrique Download PDF

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Publication number
WO2024108401A1
WO2024108401A1 PCT/CN2022/133568 CN2022133568W WO2024108401A1 WO 2024108401 A1 WO2024108401 A1 WO 2024108401A1 CN 2022133568 W CN2022133568 W CN 2022133568W WO 2024108401 A1 WO2024108401 A1 WO 2024108401A1
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Prior art keywords
battery pack
charging
switch
parallel
discharging
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PCT/CN2022/133568
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English (en)
Chinese (zh)
Inventor
陈金怀
胡良
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厦门新能达科技有限公司
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Priority to PCT/CN2022/133568 priority Critical patent/WO2024108401A1/fr
Publication of WO2024108401A1 publication Critical patent/WO2024108401A1/fr

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    • 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
    • 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

Definitions

  • the embodiments of the present application relate to the field of battery technology, and in particular to a battery pack parallel connection method, a battery management system, a battery pack, an electrical device, and a storage medium.
  • battery packs When supplying power to electrical equipment, battery packs can be connected in parallel to increase the capacity of the battery, which can increase the use time of the electrical equipment. For example, a two-wheeled vehicle powered by batteries can use parallel battery packs to increase the vehicle's mileage.
  • Embodiments of the present application provide a battery pack parallel connection method, a battery management system, a battery pack, an electrical device, and a storage medium, which can reduce the circulation current between battery packs.
  • an embodiment of the present application provides a battery pack parallel connection method, the method comprising, in response to the first battery pack satisfying the first parallel connection condition and the first battery pack being in a charging state, controlling the switch on the discharge circuit to be in an off state, and the first battery pack performs charging parallel connection.
  • the first parallel connection condition may include that the operating data of the first battery pack satisfies the parallel connection condition, and the operating data includes at least one of voltage data, current data, SOC data, temperature data, and communication status.
  • the first parallel condition includes at least one of the following:
  • the voltage difference between the voltage of the first battery pack and the first voltage is within a first voltage difference range.
  • the first voltage is the minimum voltage among the battery packs; when the first battery pack is in a discharging state, the first voltage is the maximum voltage among the battery packs.
  • the difference between the SOC of the first battery pack and the first SOC is within a first SOC range, wherein when the first battery pack is in a charging state, the first SOC is the minimum SOC among the battery packs; when the first battery pack is in a discharging state, the first SOC is the maximum SOC among the battery packs.
  • the temperature of the first battery pack is within a first temperature range.
  • the first charging current rate is within a first current rate range, or the first discharging current rate is within a second current rate range.
  • the first charging current rate is the maximum charging current rate of the battery packs connected in parallel
  • the first discharging current rate is the maximum discharging current rate of the battery packs connected in parallel.
  • the communication status of the first battery pack is used to indicate that the first battery pack has successfully communicated with at least one of the parallel-connected battery packs.
  • controlling the switch on the discharge circuit to be in an off state, and the first battery pack performs parallel charging includes: controlling the switch on the discharge circuit of the first battery pack and/or each parallel battery pack to be in an off state, and the first battery pack performs parallel charging.
  • Controlling the first battery pack and/or controlling the switches on the discharge circuits of each parallel-connected battery pack to be in an off state can cut off the discharge parallel connection between the first battery pack and the parallel-connected battery packs, thereby reducing the circulating current generated between the battery packs through the discharge circuit during charging.
  • controlling the switch on the charging circuit to be in an off state, and the first battery pack performs discharge in parallel includes: controlling the switch on the charging circuit of the first battery pack and/or each parallel battery pack to be in an off state, and the first battery pack performs discharge in parallel.
  • Controlling the switches on the charging circuits of the first battery pack and/or each parallel-connected battery pack to be in an off state can cut off the parallel charging connection between the first battery pack and the parallel-connected battery packs, thereby reducing the circulating current generated between the battery packs through the charging circuit during discharge.
  • controlling the switch on the discharge circuit to be in an open state, and the first battery pack performing charging in parallel includes: in response to the first battery pack satisfying the first parallel condition, the first battery pack sends a parallel request instruction. In response to the first battery pack being in a charging state, disconnecting the switch on the discharge circuit of the first battery pack, and closing the charging switch on the charging circuit of the first battery pack.
  • controlling the switch on the discharge circuit to be in an off state, and the first battery pack performing charging in parallel includes: in response to the first battery pack satisfying the first parallel condition and the first battery pack being in a charging state, controlling the switch on the discharge circuit to be in an off state, and the first battery pack performing charging in parallel, including: in response to the first battery pack satisfying the first parallel condition, the first battery pack sends a parallel request instruction.
  • the switch on the discharge circuit of the first battery pack is in an off state, and in response to the first battery pack being in a charging state, the charging switch on the charging circuit of the first battery pack is closed.
  • controlling the switch on the charging circuit to be in an off state, and the first battery pack performing a discharge parallel connection includes: in response to the first battery pack satisfying the first parallel connection condition, the first battery pack sends a parallel connection request instruction. In response to the first battery pack being in a discharging state, disconnecting the switch on the charging circuit of the first battery pack, and closing the discharge switch on the discharge circuit of the first battery pack.
  • controlling the switch on the charging circuit to be in an off state, and the first battery pack performing a discharge parallel connection includes: in response to the first battery pack satisfying the first parallel condition, the first battery pack sends a parallel connection request instruction.
  • the switch on the charging circuit of the first battery pack is in an off state, and in response to the first battery pack being in a discharging state, closing the discharge switch on the discharge circuit of the first battery pack.
  • the parallel request instruction is used to notify other battery packs to be incorporated into the electrical equipment, so that the first battery pack and other battery packs can be roughly synchronized and connected in parallel.
  • the battery pack can also execute the parallel judgment logic. Then, the battery pack can periodically execute the parallel judgment logic at a longer interval, which can reduce the amount of calculation of the battery pack.
  • the parallel request instruction can also carry information used to indicate the charging and discharging status of the electrical equipment. Even if the battery pack cannot receive the charging signal sent by the charger, it can still correct the working status through the parallel request instruction, which can reduce the battery pack's misjudgment of the working status.
  • the battery pack parallel connection method further includes: in response to the second battery pack receiving a parallel connection request instruction, disconnecting a discharge switch on a charging circuit of the second battery pack, the second battery pack being a parallel connected battery pack. Disconnecting the discharge switch on the charging circuit of the parallel connected battery pack can disconnect the circulation path of the parallel connected battery pack, thereby reducing the circulation current.
  • closing the charging switch on the charging circuit of the first battery pack includes: closing the charging switch in response to receiving first information.
  • the first information is used to indicate that the discharge switch on the charging circuit of the second battery pack is in an open state, and the second battery pack is a parallel-connected battery pack.
  • the first information can ensure that the first battery pack performs the operation of closing the charging switch on the charging circuit only after the circulation path on the charging circuit of the parallel-connected battery pack is disconnected, thereby reducing the circulating current.
  • the discharge switch on the charging circuit of the first battery pack in response to the first battery pack satisfying the first condition, the discharge switch on the charging circuit of the first battery pack is closed, and/or, in response to the second battery pack satisfying the first condition, the discharge switch on the charging circuit of the second battery pack is closed.
  • the first condition includes at least one of the following:
  • the charging current of the battery pack is greater than or equal to the first current threshold.
  • the charging current of the battery pack is less than the first current threshold, and the voltage difference between the sum of the voltage of the battery pack and the second voltage is within a second voltage difference range.
  • the second voltage is the minimum voltage in each battery pack. Setting the first condition can limit the circulation, and the circulation path is closed only when the risk of a large circulation is small.
  • the battery pack parallel connection method further includes: in response to the first battery pack satisfying the first circulation condition, disconnecting the charging switch and the discharging switch on the charging circuit of the first battery pack.
  • the first circulation condition includes that the absolute value of the difference between the current rate of the first battery pack and the first current rate is greater than or equal to the first current rate threshold.
  • the first current rate is the maximum charging current rate among all the battery packs connected in parallel, and the current rate of the first battery pack includes a charging current rate or a discharging current rate, the charging current rate is a positive value, and the discharging current rate is a negative value.
  • the circulating current risk is also judged, which can reduce the circulating current risk.
  • the battery pack parallel connection method further includes: in response to the second battery pack receiving a parallel connection request instruction, disconnecting a charging switch on a discharge circuit of the second battery pack.
  • the second battery pack is a battery pack that has been connected in parallel. Disconnecting the charging switch on the discharge circuit of the battery pack that has been connected in parallel can disconnect the circulation path of the battery pack that has been connected in parallel, thereby reducing the circulation current.
  • closing the discharge switch on the discharge loop of the first battery pack includes: closing the discharge switch in response to receiving second information.
  • the second information is used to indicate that the charging switch on the discharge loop of the second battery pack is in an open state, and the second battery pack is a parallel-connected battery pack.
  • the second information can ensure that the first battery pack performs the operation of closing the discharge switch on the discharge loop only after the circulation path on the discharge loop of the parallel-connected battery pack is disconnected, so as to reduce the circulating current.
  • controlling the switch on the charging circuit of the first battery pack to be in an off state, and the first battery pack performing discharge parallel connection further comprising: in response to the first battery pack satisfying the second condition, closing the charging switch on the discharging circuit of the first battery pack, and/or, in response to the second battery pack satisfying the second condition, closing the charging switch on the charging circuit of the second battery pack.
  • the second condition includes at least one of the following:
  • the discharge current of the battery pack is greater than or equal to the second current threshold
  • the discharge current of the battery pack is less than the second current threshold, and the voltage difference between the voltage of the battery pack and the third voltage is within the third voltage difference range.
  • the third voltage is the maximum voltage of each battery pack. Setting the second condition can limit the circulation, and the circulation path is closed only when the risk of a large circulation is small.
  • the switch on the charging circuit of the first battery pack in response to the first battery pack satisfying the first parallel condition and the first battery pack being in a discharging state, is controlled to be in an off state, and the first battery pack performs discharge parallel connection, and further includes: in response to the first battery pack satisfying the second circulating current condition, the charging switch and the discharging switch on the discharging circuit of the first battery pack are disconnected.
  • the second circulating current condition includes that the absolute value of the difference between the current rate of the first battery pack and the second current rate is greater than or equal to the second current rate threshold.
  • the second current rate is the maximum discharge current rate among the battery packs that have been connected in parallel, and the current rate of the first battery pack includes a charging current rate or a discharging current rate, the charging current rate is a positive value, and the discharging current rate is a negative value.
  • the circulating current risk is also judged, which can reduce the circulating current risk.
  • the battery pack parallel connection method further includes: detecting the on-off state of the charging switch and/or the discharging switch on the charging circuit of the battery pack, and sending a third information; and/or detecting the on-off state of the charging switch and/or the discharging switch on the discharging circuit of the battery pack, and sending a fourth information.
  • the third information is used to indicate the on-off state of the charging switch and/or the discharging switch on the charging circuit
  • the fourth information is used to indicate the on-off state of the charging switch and/or the discharging switch on the discharging circuit.
  • the third information and the fourth information can be referred to as back-check information.
  • the battery pack parallel connection method further includes: the switch on the discharge circuit responds to the control signal and extends the first time to perform on-off, and the switch on the charging circuit responds to the control signal and extends the second time to perform on-off. After receiving the control signal, the switch on the charge and discharge circuit extends a period of time before performing on-off or off, which can ensure that the switch is normally closed or opened, making the parallel connection of the battery pack more stable.
  • an embodiment of the present application also provides a battery management system, comprising at least one processor and a memory, wherein the memory is communicatively connected to the at least one processor, and the memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the above method.
  • an embodiment of the present application further provides a battery pack, comprising the above-mentioned battery management system.
  • an embodiment of the present application further provides an electrical device, including a load and the above-mentioned battery pack, wherein the battery pack is used to supply power to the load.
  • an embodiment of the present application further provides a storage medium, which stores computer-executable instructions.
  • the computer-executable instructions When executed by a machine, the machine executes the above-mentioned method.
  • the embodiment of the present application disconnects the discharge circuit when the battery pack is charging, and disconnects the charging circuit when the battery pack is discharging. This can reduce the circulating current generated between the battery packs through the discharge circuit during charging, and the circulating current generated through the charging circuit during discharging, thereby reducing the circulating current between the battery packs and improving the safety of the battery pack.
  • the switch on the charging circuit is controlled to be in the disconnected state, which can reduce the voltage at the charging port, and when the charging circuits of the first battery pack and the battery packs that have been connected in parallel are disconnected, the charging port can be de-energized. Thereby, the safety of the charging port is improved, and the risk of electric shock from contacting the charging port is reduced.
  • the present embodiment can directly control the switch on the discharge circuit to be in the disconnected state to perform charging in parallel.
  • the present embodiment can directly control the switch on the charging circuit to be in the disconnected state to perform discharging in parallel.
  • the working state can be easily switched without shutting down and restarting, or each battery pack exiting the parallel connection and then reconnecting the parallel connection, and the process is relatively simple.
  • FIGS 1a to 1c are schematic diagrams of the structure of electrical equipment according to an embodiment of the present application.
  • FIG. 2a-FIG. 2c and FIG. 3 are schematic diagrams of the structure of a battery pack according to an embodiment of the present application.
  • 4a-4c are working state diagrams of the discharge circuit of the battery pack according to the embodiment of the present application.
  • 5a-5c are working state diagrams of the charging circuit of the battery pack according to the embodiment of the present application.
  • 6a-6d are schematic diagrams of the switch structure of the charge and discharge control part of the BMS according to the embodiment of the present application.
  • FIG7 is a schematic diagram of the hardware structure of the controller in the BMS of the embodiment of the present application.
  • FIG8 is a flow chart of an embodiment of a method for connecting battery packs in parallel according to the present invention.
  • FIG9 is a schematic diagram of the switch structure of the charge and discharge control part of the BMS according to an embodiment of the present application.
  • FIG10 is a flow chart of charging in one embodiment of the battery pack parallel connection method of the present application.
  • FIG11 is a flow chart of discharging in one embodiment of the battery pack parallel connection method of the present application.
  • 12a-12d are schematic diagrams of working states at various stages during charging in one embodiment of a battery pack parallel connection method of the present application;
  • FIG13 is a schematic diagram of an interactive process of charging a battery pack in parallel according to an embodiment of the present application.
  • 14a-14d are schematic diagrams of working states at various stages during charging in one embodiment of a battery pack parallel connection method of the present application
  • FIG15 is a schematic diagram of an interactive process when discharging a battery pack in parallel according to an embodiment of the present application
  • FIG. 16 is a schematic diagram of the interactive process when charging the battery packs in parallel according to an embodiment of the present application.
  • the device schematic diagram is divided into functional modules and the flowchart shows a logical order, in some cases, the steps may be divided into modules different from those in the device or may be executed in an order different from that shown in the flowchart.
  • FIG. 1a shows the structure of the battery-related part of the electrical device 1000, which includes N parallel connected battery packs 100, namely battery pack 1 to battery pack N, where N is a natural number ⁇ 2, and each battery pack 100 can be used as an energy module of the electrical device.
  • the electrical equipment 1000 may be an electric vehicle, or other equipment that can be powered by a parallel battery pack, such as an electric two-wheeler, an electric three-wheeler, etc.
  • the power-consuming device 1000 may include a charging and discharging port, through which the battery pack 100 of the power-consuming device 1000 may be charged and discharged.
  • the charging and discharging ports of the power-consuming device 1000 may adopt a different port scheme, and the charging and discharging different port scheme may be understood as the charging port and the discharging port being different ports.
  • the charging and discharging ports may be different connection ports on a connector.
  • each battery pack shares a negative electrode port, that is, the negative electrode charging port C- and the negative electrode discharging port P- of the electric device 1000 are the same connection port on the connector, while the positive electrode charging port C+ and the positive electrode discharging port P+ of the electric device 1000 are different connection ports on the connector. It can be understood that, in the scheme shown in FIG1a, the negative electrode charging port C- and the negative electrode discharging port P- are the same port, and the positive electrode charging port C+ and the positive electrode discharging port P+ are different ports.
  • the discharge port of the electric device 1000 is used to electrically connect the load 200 of the electric device 1000 to supply power to the load 200.
  • the load may be an electric device on the electric vehicle, such as a motor, an instrument, a vehicle controller, etc.
  • the charging port of the electric device 1000 is used to electrically connect to the charger 2000, and the charger is used to connect to an external power source to charge the electric device 1000, specifically the battery pack 100.
  • the battery pack 100 may be provided with corresponding electrical connection terminals (e.g., connectors or connection harnesses) for respectively electrically connecting to the charging and discharging ports of the power-consuming device 1000.
  • the battery pack 100 has a C+ terminal, a P+ terminal, and a P-(C-) terminal, respectively, for respectively electrically connecting to the port C+, the port P+, and the port P-(C-) of the power-consuming device 1000.
  • each battery pack may also share a common positive electrode and a common positive electrode port P+ (C+).
  • the positive charging port C+ and the positive discharging port P+ of the electric device 1000 are the same connection port on the connector, while the negative charging port C- and the negative discharging port P- of the electric device 1000 are different connection ports on the connector.
  • the battery pack 100 respectively has a P+(C+) terminal, a C- terminal and a P- terminal, which are used to electrically connect to the port P+(C+), the port C- and the port P- of the power-consuming device 1000 respectively.
  • the battery packs may not share ports, the charging port includes port C+ and port C-, and the discharging port includes port P+ and port P-.
  • the battery pack 100 respectively has a C+ terminal, a C- terminal, a P+ terminal and a P- terminal, which are used to electrically connect the corresponding ports C+, C-, P+ and P- of the electrical device.
  • the battery pack has a C+ terminal, a C- terminal, a P+ terminal, and a P- terminal as shown in FIG2c.
  • the C+ terminal may be electrically connected to the port C+
  • the P+ terminal may be electrically connected to the port P+
  • the C- terminal and the P- terminal may be electrically connected to the port P-(C-).
  • the battery pack has a C+ terminal, a P+ terminal, and a P-(C-) terminal as shown in FIG2a.
  • the C+ terminal may be electrically connected to the port C+
  • the P+ terminal may be electrically connected to the port P+
  • the P-(C-) terminal may be electrically connected to the port C- and the port P-, respectively.
  • the charging port and/or the discharging port may be provided in the form of a connection port or a connector.
  • the discharging port since the discharging port does not need to be connected to an external device but only needs to be connected to a load inside the electrical device, there is no need to provide a connection port or a connector, and the battery pack may be directly electrically connected to the corresponding load using a connection harness.
  • each battery pack 100 includes a battery management system (BMS) 10 and an energy module 20 (eg, a battery cell module).
  • BMS battery management system
  • energy module 20 eg, a battery cell module
  • the energy module 20 includes a plurality of cells for storing and providing electric energy.
  • the plurality of cells can be connected in series, in parallel or in a mixed connection.
  • the mixed connection of the plurality of cells means that the electrical connection of the cells includes both series connection and parallel connection.
  • the BMS 10 is used to detect, manage, control and/or protect the energy module 20.
  • the BMS 10 can detect the operating data of the energy module 20 and/or the communication status of the battery pack, such as voltage data, current data, temperature data, capacity (State of Charge, SOC) data, etc.
  • each BMS10 on each battery pack 100 can be communicatively connected to each other.
  • each BMS10 is communicatively connected via a communication bus 300 .
  • each battery pack 100 can exchange instructions and data (such as the above-mentioned operating data).
  • the charger may also be communicatively connected to the BMS10 of each battery pack, for example, by being communicatively connected to the BMS10 of each battery pack through a communication bus, and sending a charging signal to each battery pack, and the charging signal may be used to instruct the battery pack to perform a charging operation.
  • the communication bus 300 is such as a CAN communication bus, an RS485 communication bus, etc.
  • each BMS10 and the charger and the BMS10 can also be communicated and connected through other wired or wireless methods, such as through Wi-Fi communication, mobile communication technology or Bluetooth communication technology.
  • the energy modules 20 of each battery pack 100 may be electrically connected in parallel to supply power to the power-consuming device 1000 , so as to increase the battery capacity of the power-consuming device 1000 .
  • the energy module 20 can be connected in parallel with other energy modules through the BMS 10.
  • Electrical connection terminals for connecting the charging and discharging ports of electrical equipment can be set on the BMS 10, one end of the electrical connection terminal is used to connect the energy module 20, and the other end is used to connect the charging and discharging port.
  • the C+ terminal, P+ terminal and P+(C+) terminal of the electrical connection terminal are used to connect the positive electrode of the energy module 20, and the C- terminal, P- terminal and P-(C-) terminal are used to connect the negative electrode of the energy module 20.
  • the electrical connection terminal can be configured as a connection port or a connector, or can also be a section of a connection harness.
  • the BMS 10 may be presented in the form of a printed circuit board, and a switch may be further provided on the BMS 10 circuit board, for example, provided between the energy module 20 and the electrical connection end, and the BMS 10 may control the switch to incorporate the energy module 20 into the electrical device 1000 or to cut out the electrical device 1000.
  • the BMS 10 controls the switch to establish a connection between the energy module 20 and the electrical connection end, the energy module 20 is incorporated into the electrical device 1000, and when the BMS 10 controls the switch to disconnect the connection between the energy module 20 and the electrical connection end, the energy module 20 is cut out of the electrical device 1000.
  • the energy module 20 is integrated into or disconnected from the electrical equipment, which is called the battery pack is integrated into or disconnected from the electrical equipment, and the energy modules 20 are connected in parallel, which is called the battery pack is connected in parallel.
  • different circuits can be used to charge and discharge the battery pack 100, using the charging circuit to charge the battery pack 100 and the discharging circuit to discharge the battery pack 100.
  • the charging circuit is electrically connected to the charging port of the electrical device, and the discharging circuit is electrically connected to the discharging port of the electrical device.
  • Switches may be provided on the charging circuit and the discharging circuit respectively.
  • at least one switch may be provided on the charging circuit to control the on and off of the charging circuit
  • at least one switch may be provided on the discharging circuit to control the on and off of the discharging circuit.
  • the battery pack 100 By closing or opening the switch on the BMS 10, the battery pack 100 is connected to or disconnected from the electrical equipment 1000.
  • the BMS 10 controls the switch to turn on the charging circuit, the battery pack is connected to the electrical equipment, and the battery pack is "charged in parallel”.
  • the BMS 10 controls the switch to turn on the discharging circuit, the battery pack is connected to the electrical equipment, and the battery pack is "discharged in parallel”.
  • Fig. 3 shows a structure of the charge and discharge control part of the BMS 10. It can be understood that the figure only shows the switch structure of the charge and discharge control part of the BMS, and does not show other structures such as the main control part and the detection part.
  • the discharge circuit of the BMS10 includes a charging switch CHG1 and a discharging switch DSG1 connected in series.
  • the charging switch CHG1 and the discharging switch DSG1 may be field effect transistors
  • the charging switch CHG1 includes a body diode D1
  • the discharging switch DSG1 includes a body diode D2.
  • the charging switch CHG1 is connected in parallel with a diode D1
  • the discharging switch DSG1 is connected in parallel with a diode D2
  • the diode D1 and the diode D2 share a common cathode.
  • the charging switch CHG1, the discharging switch DSG1, the diode D1, and the diode D2 may be used as part of the discharge circuit, and the charging switch CHG1 and the discharging switch DSG1 are used to control the working state of the discharge circuit.
  • the charging circuit of BMS10 may include a charging switch CHG2 and a discharging switch DSG2 connected in series.
  • the charging switch CHG2 and the discharging switch DSG2 may be field effect transistors
  • the charging switch CHG2 includes a body diode D3
  • the discharging switch DSG2 includes a body diode D4.
  • the charging switch CHG2 is connected in parallel with a diode D3
  • the discharging switch DSG2 is connected in parallel with a diode D4
  • the diode D3 and the diode D4 share a common cathode.
  • the charging switch CHG2, the discharging switch DSG2, the diode D3, and the diode D4 may be used as part of the charging circuit, and the charging switch CHG2 and the discharging switch DSG2 are used to control the working state of the charging circuit.
  • the charging switch CHG2 when the charging switch CHG2 is closed and the discharging switch DSG2 is opened, the charging path of the energy module 20 is turned on, and the external power supply can charge the energy module 20 through the charging path and the charging ports C+ and P-(C-).
  • the current direction is: the positive electrode of the external power supply ⁇ C+ ⁇ the diode D4 ⁇ the charging switch CHG2 ⁇ the positive electrode of the energy module 20 ⁇ the negative electrode of the energy module 2020 ⁇ P-(C-) ⁇ the negative electrode of the external power supply.
  • FIG6a and FIG6b take two battery packs as an example to exemplarily illustrate the switch structure of the charge and discharge control part when the battery packs share a negative electrode
  • FIG6c and FIG6d take two battery packs as an example to exemplarily illustrate the switch structure of the charge and discharge control part when the battery packs share a positive electrode.
  • the following embodiments are all described by taking the battery packs sharing a negative electrode as an example.
  • the BMS 10 may further include a pre-discharge switch (PDSG1, PDSG2) and a current limiting resistor (R1, R2), and the pre-discharge switch is connected in series with the current limiting resistor.
  • the pre-discharge switch may be a field effect transistor, and the pre-discharge switch may include a body diode (D9, D10). In some other embodiments, the pre-discharge switch is connected in parallel with a diode (D9, D10).
  • the current limiting resistor can limit the discharge current.
  • the BMS10 can control the pre-discharge switch to be closed first, and keep the discharge switch in the open state, so that the discharge current flows through the current limiting resistor and decreases, thereby reducing the risk of damage to the discharge switch and the charging switch. After discharging for a period of time, the discharge switch is closed again and the pre-discharge switch is disconnected.
  • the charge and discharge control part may also adopt other switch structures, such as including only one switch in the charging circuit and/or only one switch in the discharging circuit.
  • more than one charging switch and/or more than one discharging switch may be provided on the charging circuit. More than one charging switch and/or more than one discharging switch may be provided on the discharging circuit.
  • the above-mentioned charging switch and/or discharging switch can be one of a triode, a field effect transistor, a signal relay, an insulated gate bipolar transistor (IGBT), or other controllable switches that can control the conduction or shutdown of the circuit.
  • IGBT insulated gate bipolar transistor
  • the BMS 10 may further include a switch driving circuit and at least one controller for controlling the closing and opening operations of the above switches to execute the steps in any method embodiment of the present application.
  • FIG7 schematically shows the hardware structure of the controller.
  • the controller includes a processor 11 and a memory 12 .
  • the memory 12 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs and non-volatile computer-executable program instructions.
  • the memory 12 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and an application required for at least one function; and the data storage area may store data created according to the use of the BMS 10, etc.
  • the memory 12 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device.
  • the memory 12 may optionally include a memory remotely arranged relative to the processor 11, and these remote memories may be connected to the BMS 10 via a network.
  • Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network and combinations thereof.
  • the processor 11 uses various interfaces and lines to connect various parts of the entire BMS 10, and executes various functions of the BMS 10 and processes data by running or executing software programs stored in the memory 12 and calling data stored in the memory 12, such as implementing the method described in any embodiment of the present application.
  • the processor 11 may include a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) device, etc.
  • the processor 11 may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration.
  • one processor 11 and one memory 12 are used as examples.
  • the BMS 10 includes a multi-level management unit, or when multiple processors need to work together, the BMS 10 can also include multiple processors, and the method described in any embodiment of the present application can be implemented by multiple processors working together.
  • the memory can also be one or more, and the processor 11 and the memory 12 can be connected through a bus or other means. In the embodiment shown in FIG7, the processor 11 and the memory 12 are connected through a bus.
  • the embodiments of the present application also provide a battery pack parallel connection method, which can be applied to the BMS in any of the above embodiments, wherein “battery pack parallel connection” and “battery pack parallel operation” can mean that the battery pack is integrated into an electrical device.
  • the battery pack parallel connection method includes:
  • the switch on the discharge circuit when the battery pack is charged, the switch on the discharge circuit is controlled to be in an off state, so that the discharge circuit is in an off state, the "discharge parallel connection" between the battery pack and other battery packs can be cut off, and the circulating current generated by the discharge circuit between the battery packs during charging can be reduced.
  • the switch on the charging circuit is controlled to be in an off state, so that the charging circuit is in an off state, the "charge parallel connection" between the battery pack and other battery packs can be cut off, and the circulating current generated by the charging circuit during discharge can be reduced.
  • some embodiments of the present application can directly control the switch on the discharge circuit to be in an off state to perform charging in parallel.
  • some embodiments of the present application can directly control the switch on the charging circuit to be in an off state to perform discharging in parallel.
  • the working state of the battery pack can be easily converted without shutting down and restarting, or all battery packs are withdrawn from parallel connection and then reconnected, and the process is simpler.
  • controlling the switch on the discharge circuit to be in an off state may be controlling the switch on the discharge circuit of the first battery pack to be in an off state.
  • the BMS of the first battery pack puts its discharge circuit in a disconnected state.
  • the BMS of other battery packs can also put their discharge circuits in a disconnected state. Then, the discharge circuits of all the battery packs in parallel charging are in a disconnected state, and the "discharge parallel" between the battery packs is cut off, which can reduce the circulating current generated by the discharge circuit.
  • the switch on the discharge circuit when the first battery pack is charged, the switch on the discharge circuit is controlled to be in an open state, and the switches on the discharge circuits of each parallel battery pack can also be controlled to be in an open state.
  • the discharge circuits of each parallel battery pack are in an open state, the "discharge parallel” formed by the first battery pack and the parallel battery packs through the discharge circuit is disconnected, which can reduce the circulating current generated by the discharge circuit.
  • the "parallel battery pack” here can be "a battery pack whose switch on the discharge circuit is closed and has been incorporated into the electrical device.”
  • a control instruction may be transmitted to the BMS of each parallel-connected battery pack, instructing the BMS of each parallel-connected battery pack to control the switch on its discharge circuit to be in an off state.
  • the switch on the discharge circuit is controlled to be in an off state, or the switches on the discharge circuits of the first battery pack and each battery pack connected in parallel are controlled to be in an off state.
  • the switch on its own discharge circuit is controlled to be in an off state, so as to achieve the effect that the switches on the discharge circuits of each battery pack in the electrical device are all in an off state.
  • controlling the switch on the charging circuit to be in an off state may be controlling the switch on the charging circuit of the first battery pack to be in an off state.
  • the BMS of the first battery pack puts its charging circuit in a disconnected state.
  • the BMS of other battery packs can also put their charging circuits in a disconnected state. Then, the charging circuits of all the battery packs in discharge parallel can be in a disconnected state, and the "charging parallel" between the battery packs can be cut off, which can reduce the circulating current generated by the charging circuit.
  • the charging circuit when the charging circuit is in the disconnected state, the connection between the battery pack and the charging port is disconnected, so that the charging port is not charged, which improves the safety of the charging port and reduces the risk of electric shock caused by contact with the charging port.
  • the switch on the charging circuit when the first battery pack is discharged, the switch on the charging circuit is controlled to be in an off state, and the switches on the charging circuits of the parallel-connected battery packs may also be controlled to be in an off state.
  • the charging circuits of the parallel-connected battery packs are in an off state, the "charging parallel” formed by the first battery pack and the parallel-connected battery packs through the charging circuit is disconnected, which can reduce the circulating current generated by the charging circuit.
  • the "parallel-connected battery pack” here can be "a battery pack whose switch on the charging circuit is closed and has been connected to the power-consuming device".
  • a control instruction may be transmitted to the BMS of each parallel-connected battery pack, instructing the BMS of each parallel-connected battery pack to control the switch on its charging circuit to be in an off state.
  • the switch on the charging circuit is controlled to be in the off state. It is also possible to control the switches on the charging circuits of the first battery pack and each parallel-connected battery pack to be in the off state. Alternatively, when each battery pack in the electrical equipment determines that it is in a discharging state, the switch on its own charging circuit is controlled to be in the off state, so as to achieve the effect that the switches on the charging circuits of each battery pack in the electrical equipment are in the off state.
  • controlling the switch on the battery pack discharge circuit to be in an off state may be controlling each switch on the battery pack discharge circuit to be in an off state.
  • the discharge circuit includes a switch
  • the switch is controlled to be in an off state.
  • the charging switch CHG1 and the discharging switch DSG1 are controlled to be in an off state.
  • Controlling the switch on the battery pack charging circuit to be in an off state may be controlling each switch on the battery pack charging circuit to be in an off state.
  • the switch is controlled to be in an off state.
  • the charging switch CHG2 and the discharging switch DSG2 are controlled to be in an off state.
  • the battery pack in order to improve the safety of the battery pack when it is integrated into the electrical equipment, it is detected whether the operating data of the battery pack meets the parallel connection condition, and the battery pack is only integrated when the battery pack meets the first parallel connection condition.
  • the operating data includes at least one of voltage data, current data, SOC data, temperature data, and communication status.
  • the first parallel connection condition includes at least one of the following:
  • a voltage difference between the voltage of the first battery pack and the first voltage is within a first voltage difference range.
  • the circulating current formed between the battery packs is correspondingly large, and when the voltage difference between the battery packs is small, the circulating current formed between the battery packs is correspondingly small. Keeping the voltage difference between the voltage of the first battery pack and the first voltage within a certain voltage difference range can further reduce the circulating current between the battery packs.
  • the first voltage may be an average voltage of each battery pack, or a maximum voltage or a minimum voltage of each battery pack. In some embodiments, when the first battery pack is in a charging state, the first voltage is the minimum voltage of each battery pack, and when the first battery pack is in a discharging state, the first voltage is the maximum voltage of each battery pack.
  • the value of the first voltage distinguishes the charging and discharging states.
  • the first voltage In the charging state, the first voltage is the minimum voltage, and in the discharging state, the first voltage is the maximum voltage, which can further reduce the circulating current between the battery packs.
  • the battery pack is in charging parallel operation, if the voltage difference between the battery pack and the battery pack with the smallest voltage is small, the charging current and discharging current between the battery packs can be well limited, thereby limiting the circulating current between the battery packs. If the battery pack is in discharging parallel operation, if the voltage difference between the battery pack and the battery pack with the largest voltage is small, the charging current and discharging current between the battery packs can be well limited, thereby limiting the circulating current between the battery packs.
  • the charging current and discharging current between battery packs means that when two battery packs are in parallel operation, the battery pack with a higher voltage will discharge the battery pack with a lower voltage to form a discharge current, and the battery pack with a lower voltage will be charged by the battery pack with a higher voltage to form a charging current.
  • the battery packs may be all the battery packs in the electrical device, or may be battery packs connected in parallel.
  • a difference between the SOC of the first battery pack and the first SOC is within a first SOC range.
  • the circulating current formed between the battery packs is correspondingly large, and when the SOC difference between the battery packs is small, the circulating current between the battery packs is correspondingly small. Keeping the SOC difference between the first battery pack and the first SOC within a certain SOC range can further reduce the circulating current between the battery packs.
  • the first SOC may be the average SOC of each battery pack, or the maximum SOC or minimum SOC of each battery pack. In some embodiments, when the first battery pack is in a charging state, the first SOC is the minimum SOC of each battery pack, and when the first battery pack is in a discharging state, the first SOC is the maximum SOC of each battery pack.
  • the value of the first SOC distinguishes the charging and discharging states.
  • the first SOC In the charging state, the first SOC is the minimum SOC, and in the discharging state, the first SOC is the maximum SOC, which can further reduce the circulating current between the battery packs.
  • the battery pack is in the process of charging and parallel operation, if the SOC difference between the battery pack and the battery pack with the smallest SOC value is small, the charging current and discharging current between the battery packs can be well limited, thereby limiting the circulating current between the battery packs. If the battery pack is in the process of discharging and parallel operation, if the SOC difference between the battery pack and the battery pack with the largest SOC value is small, the charging current and discharging current between the battery packs can be well limited, thereby limiting the circulating current between the battery packs.
  • the battery packs may be all the battery packs in the electrical equipment, or may be battery packs connected in parallel.
  • the temperature of the first battery pack is within the first temperature range.
  • Limiting the temperature of the first battery pack to within the first temperature range can reduce damage to other battery packs due to excessively high or low temperatures, or reduce the risk of thermal runaway caused by parallel operation.
  • the first charging current rate is within a first current rate range, or the first discharging current rate is within a second current rate range.
  • the first charging current rate is the maximum charging current rate of the battery packs connected in parallel
  • the first discharging current rate is the maximum discharging current rate of the battery packs connected in parallel.
  • the first battery pack When the first battery pack is to be connected to an electrical device, if there is a large charging current or a large discharging current in the parallel-connected battery pack, a large circulating current may flow into the first battery pack, damaging the switch device in the first battery pack. Moreover, due to the large charging current or discharging current, the voltage, power and other detection values of the battery pack may be affected by the load and the detection may be inaccurate. At this time, parallel connection may also have certain risks.
  • the maximum discharge current rate of each battery pack connected in parallel is obtained. If the maximum discharge current rate exceeds the second current rate range, the first battery pack is not integrated. During charging, the maximum charge current rate of each battery pack connected in parallel is obtained. If the maximum charge current rate exceeds the first current rate range, the first battery pack is not integrated.
  • the first parallel condition includes that the first charging current is within the first current range, or the first discharging current is within the second current range.
  • the first charging current is the maximum charging current of the battery packs that have been connected in parallel
  • the first discharging current is the maximum discharging current of the battery packs that have been connected in parallel.
  • the first battery pack can obtain the charging current rate or discharging current rate, charging current value or discharging current value of other battery packs by communication, for example, through a communication bus.
  • the communication status of the first battery pack is used to indicate that the first battery pack has successfully communicated with at least one of the battery packs.
  • the first battery pack receives a message from any other battery pack, it can be considered that the first battery pack has successfully communicated with any of the battery packs, and the merging operation (including determining whether the first parallel condition is met, etc.) can be performed.
  • the first battery pack when the first battery pack does not receive a message from any battery pack, the first battery pack does not determine whether the first battery pack meets the first parallel condition, but is directly integrated into the power-consuming device and works as a single battery pack.
  • the first parallel connection condition may include one of the above conditions, or include at least two of the above conditions at the same time.
  • the first parallel connection condition includes at least two of the above conditions, the first battery pack must meet at least two conditions at the same time before the first battery pack can perform the incorporation operation.
  • the first pressure difference range, the first SOC range, the first temperature range, the first current rate range, and the second current rate range can be set according to specific application conditions, for example, according to the applicability of the battery pack, including: the characteristics of the battery cells in the battery pack (including the maximum allowable charge and discharge rate and/or time of the battery cells), the overcurrent capacity of the connector or connecting harness, the withstand voltage and overcurrent capacity of the electrical equipment, the performance of components in the battery pack (such as switches), and other settings.
  • the first pressure difference range can be set according to the internal resistance of the battery pack and the ability to withstand the maximum circulating current.
  • the pressure difference range can be roughly the product of the tolerable circulating current size and the internal resistance of the battery pack.
  • the first pressure difference range can be [-1V, 1V], [-0.5V, 0.5V], etc.
  • the first pressure difference range is not intended to limit the present application.
  • the SOC difference between the battery packs can affect the circulation time between the battery packs.
  • the first SOC range can be set to [-5%, 5%].
  • the first temperature range may be set to [-10, 50°C]
  • the first current multiplier range may be set to 0.2-0.3°C
  • the second current multiplier range may be set to 2-3°C.
  • the electric device when the electric device is connected to the charger, it can be considered that the electric device and the battery pack are in a charging state.
  • the electric device When the electric device is not connected to the charger, it can be considered that the electric device and the battery pack are in a discharging state.
  • the discharge can include discharging the electronic components in the BMS (for example, powering the MCU on the BMS circuit board) and discharging the load of the electric device (for example, discharging the load such as the motor of the electric vehicle).
  • the discharge state of the battery pack includes the standby state and the working state.
  • the battery pack can confirm that it is in a charging state through a charging signal.
  • the charger when the charger is connected to the charging port, the charger sends a charging signal to the battery pack through data communication. After the battery pack receives the charging signal, it can be confirmed that the battery pack is in a charging state.
  • a hardware detection circuit may be provided on the BMS to detect whether a charger is plugged into the charging port. Before and after the charger is plugged in, the hardware detection circuit outputs different level signals. After the controller on the BMS detects that the level signal is flipped, it can be determined that the charger has been plugged into the charging port and the electrical device and the battery pack are in a charging state.
  • FIG. 10 shows an embodiment of a method for connecting battery packs in parallel during charging, the method comprising:
  • the first battery pack In response to the first battery pack satisfying the first parallel connection condition, the first battery pack sends a parallel connection request instruction.
  • the first battery pack executes parallel judgment logic (including judging whether the battery pack meets the first parallel condition), and when the first battery pack meets the first parallel condition, the first battery pack sends a parallel request instruction.
  • parallel judgment logic including judging whether the battery pack meets the first parallel condition
  • the first battery pack sends a parallel request instruction.
  • the switch on the discharge circuit of the first battery pack is disconnected, so that the discharge circuit is in an open state, and the charging switch on the charging circuit of the first battery pack is closed, so that the charging path of the charging circuit is turned on, and the first battery pack can be charged through the charging path.
  • 101b may also include: in response to the first battery pack being in the charging state, closing the charging switch on the charging circuit of the first battery pack.
  • the charging switch CHG1 and the discharging switch DSG1 are opened, and the charging switch CHG2 is closed.
  • FIG. 11 shows an embodiment of a method for connecting battery packs in parallel during discharge, the method comprising:
  • the first battery pack In response to the first battery pack satisfying the first parallel connection condition, the first battery pack sends a parallel connection request instruction.
  • the first battery pack executes parallel judgment logic, and when the first battery pack meets the first parallel condition, the first battery pack sends a parallel request instruction.
  • the switch on the charging circuit of the first battery pack is disconnected, so that the charging circuit is in a disconnected state, and the discharge switch on the discharge circuit of the first battery pack is closed, so that the discharge path of the discharge circuit is turned on, and the first battery pack can discharge through the discharge path.
  • 102b may also include: in response to the first battery pack being in the discharging state, closing the discharge switch on the discharge circuit of the first battery pack.
  • the first battery pack in response to the first battery pack meeting the first parallel condition, the first battery pack sends a parallel request instruction.
  • the charging switch CHG2 and the discharging switch DSG2 are opened, and the discharging switch DSG1 is closed.
  • the parallel connection request instruction can be used to notify other battery packs to be connected to the power-consuming device.
  • the other battery packs are also connected to the power-consuming device, so that the first battery pack and other battery packs are roughly synchronously connected to each other.
  • the battery pack in the electrical device can periodically execute the parallel judgment logic at a certain interval (e.g., 1S, 2S, etc.), and the battery pack will also execute the parallel judgment logic after receiving the parallel request instruction sent by other battery packs. Since the parallel request instruction will form an event trigger, triggering the battery pack to execute the parallel judgment logic, the battery pack can periodically execute the parallel judgment logic at a longer interval, which can reduce the amount of calculation of the battery pack.
  • a certain interval e.g., 1S, 2S, etc.
  • the parallel request instruction can also carry information used to indicate the charging and discharging status of the electrical equipment.
  • the battery pack may misjudge the charging and discharging status. For example, battery pack A is still in the discharging state because it has not received the charging signal sent by the charger. If battery pack A can receive the parallel request instruction sent by other battery packs, the working state of battery pack A can be corrected and changed to the charging state. In other words, the parallel request instruction can reduce the battery pack's misjudgment of the working state.
  • the following describes the parallel charging and parallel discharging methods of the battery packs, that is, the control of the charging circuit when the battery pack is charged, and the control of the discharging circuit when the battery pack is discharged.
  • the first battery pack performs parallel charging, including: closing a charging switch on a charging circuit of the first battery pack. Alternatively, it includes: closing a charging switch and a discharging switch on a charging circuit of the first battery pack.
  • the other battery packs may transmit circulating current to the first battery pack through the circulating current paths of the other battery packs.
  • the battery packs performing parallel charging also include operating the circulating current path.
  • the electric device is in the charging state
  • the battery pack BT1 is not incorporated (the battery pack BT1 can represent an uncharged parallel battery pack), and the battery pack BT2 is incorporated (the battery pack BT2 can represent one or more charged parallel battery packs).
  • FIG12a for the status of the battery packs BT1 and BT2.
  • the battery pack BT1 can be charged in parallel in the following four stages:
  • Phase 1 Disconnect the circulation path of BT2.
  • the conduction and disconnection of the circulation path in the charging circuit can be controlled by the discharge switch.
  • Disconnecting the circulation path can be by disconnecting the discharge switch in the charging circuit.
  • disconnecting the circulation path of BT2 includes disconnecting the discharge switch DSG4 of BT2. Before closing the switch on the charging circuit of the battery pack BT1, the battery pack BT2 can be cut off from transmitting the circulation current to the battery pack BT1 through the circulation path. Please refer to Figure 12b.
  • the battery pack BT2 disconnects the discharge switch on the charging circuit of the battery pack BT2 in response to receiving a parallel request instruction (in this embodiment, receiving a parallel request instruction sent by BT1).
  • a parallel request instruction in this embodiment, receiving a parallel request instruction sent by BT1.
  • BT2 is in a charged parallel state.
  • the circulation path of BT2 is first disconnected, and then the charging path of BT1 is closed.
  • the charging circuit and the discharging circuit of each battery pack are in a disconnected state, and the circulation path of each battery pack is in a disconnected state.
  • This stage 1 can be omitted, and stage 1 can be directly skipped to execute stage 2.
  • the circulation path of the second battery pack BT2 can be disconnected by executing the operation of stage 1.
  • Phase 2 Turn on the charging path of BT1.
  • the on and off of the charging path in the charging circuit can be controlled by the charging switch, and the on charging path can be the charging switch in the closed charging circuit.
  • the charging path of BT1 includes closing the charging switch CHG2 of BT1.
  • the battery pack BT1 can be charged through the charging path, please refer to FIG12c.
  • the battery pack BT1 in order to confirm that the circulation path of the parallel battery pack is in a disconnected state and reduce the circulation, closes the charging switch on the charging circuit in response to receiving the first information.
  • the first information is used to indicate that the circulation path of the battery pack BT2 has been disconnected. In this embodiment of the present application, it can be that the discharge switch on the charging circuit of the battery pack BT2 is in a disconnected state.
  • Phase 3 Turn on the circulation path of BT1 and BT2.
  • the conducting loop current path can be achieved by closing the discharge switch in the charging loop.
  • the conducting loop current path of BT1 includes closing the discharge switch DSG2
  • the conducting loop current path of BT2 includes closing the discharge switch DSG4 of BT2, please refer to FIG. 12d.
  • stage 3 further includes: in response to the operating data of the battery pack BT1 satisfying the first condition, closing the discharge switch on the charging circuit of the battery pack BT1, and/or, in response to the operating data of the battery pack BT2 satisfying the first condition, closing the discharge switch on the charging circuit of the battery pack BT2.
  • the first condition is used to indicate the condition for limiting the circulating current, and may include at least one of the following conditions:
  • the charging current of the battery pack is greater than or equal to the first current threshold.
  • the charging current of the battery pack is less than the first current threshold, and the voltage difference between the voltage of the battery pack and the second voltage is within a second voltage difference range.
  • the internal resistance of the battery pack is considered to be roughly the same. Then, the larger the charging current, the larger the voltage difference between the battery pack BT1 and the charger, and the smaller the battery pack voltage.
  • the charging current of the battery pack BT1 is greater than or equal to the first current threshold, the voltage difference between the battery pack and the charger is large, the voltage of the battery pack is small, and the battery pack with a small voltage needs to be charged first. Because charging the battery pack with a small voltage first can reduce the voltage difference between the battery packs, it can be considered that the battery pack BT1 meets the circulation limit conditions.
  • Battery pack BT1 may discharge to other battery packs (i.e., a circulation occurs). At this time, it can be further combined with other operating data to determine whether battery pack BT1 has a circulation risk.
  • the charging current of the battery pack BT1 is greater than or equal to the first current threshold, it can be considered that the first battery pack meets the circulation restriction condition, its circulation path can be turned on, and the discharge switch on the charging circuit of the battery pack BT1 is closed.
  • the charging current of the battery pack BT1 is less than the first current threshold, it can be further determined whether the voltage difference between the battery pack BT1 and the second voltage is within the second voltage difference range. If the voltage difference is within the second voltage difference range, the voltage difference between the battery packs is small, and the risk of large circulation is small.
  • the circulation path can be turned on and the discharge switch on the charging circuit of the battery pack BT1 can be closed.
  • large circulation current means that the circulation current value between the battery pack BT1 and other battery packs is larger
  • small circulation current means that the circulation current value between the battery pack BT1 and other battery packs is smaller
  • the discharge switch on the charging circuit is not closed. In some embodiments, the judgment may be made again after a period of time.
  • the second voltage may be an average voltage of each battery pack, or a maximum voltage or a minimum voltage of each battery pack. In some embodiments, the second voltage is the minimum voltage of each battery pack.
  • the second pressure difference range can be set according to specific application conditions, for example, according to the applicability of the battery pack, the performance of components (such as switches) in the battery pack, etc.
  • the second pressure difference range and the first pressure difference range can be the same or different.
  • the second pressure difference range is within the first pressure difference range, and the second pressure difference range is smaller than the first pressure difference range.
  • the first current threshold can be set according to the specific application, for example, according to the maximum charging current and/or time allowed by the battery cells in the battery pack, the model and specification of the charger, the overcurrent capacity of the connector or connecting harness, the withstand voltage and overcurrent capacity of the electrical equipment, and the performance of the components (such as switches) in the battery pack.
  • the first current threshold can be 2A.
  • Phase 4 If there is a risk of circulating current, disconnect the charging circuit of BT1 or only disconnect the circulating current path. If there is no risk of circulating current, complete the charging and parallel operation.
  • a step of further judging the circulating current risk is included. If there is a circulating current risk, the discharging switch and the charging switch on the charging circuit of the battery pack BT1 are disconnected, or only the discharging switch on the charging circuit of the battery pack BT1 can be disconnected. If there is no circulating current risk, the circulating current path of the battery pack BT1 is kept open. In other embodiments, the battery pack charging in parallel may not include stage 4.
  • Whether there is a circulation risk between battery packs can be determined by determining whether the battery pack meets a first circulation condition, wherein the first circulation condition includes that the absolute value of the difference between the current rate of the first battery pack and the first current rate is greater than or equal to a first current rate threshold.
  • the first current rate is the maximum charging current rate of each battery pack connected in parallel.
  • the charging current of each battery pack connected in parallel can be obtained, and then the maximum charging current rate is selected as the first current rate.
  • the embodiment of the present application uses the maximum charging current rate (i.e., the first current rate) of each battery pack connected in parallel as a benchmark, and uses the absolute value of the difference between the current rate of the first battery pack and the first current rate as a judgment condition, which can well identify the risk of circulation.
  • the discharge current can be specified as negative and the charge current as positive.
  • the current multiplier of the battery pack BT1 is negative
  • the first current multiplier is positive
  • the absolute value of the difference between the two is large.
  • the current multiplier of the battery pack BT1 and the first current multiplier are both positive. If the current multiplier of the battery pack BT1 differs greatly from the first current multiplier, the absolute value of the difference between the two is also large.
  • the discharge current can also be specified as positive and the charge current can be specified as negative.
  • the presence of a circulating current risk may also be determined by the charging current value.
  • the first circulating current condition may also include: the absolute value of the difference between the current of the first battery pack and the first current is greater than or equal to the first current threshold.
  • the first current is the maximum charging current of each battery pack connected in parallel.
  • the first current rate threshold can be set according to the specific application situation, for example, it can be determined according to the maximum charging current and/or time allowed by the battery cells in the battery pack, the model and specifications of the charger, the overcurrent capacity of the connector or connecting harness, the voltage resistance and overcurrent capacity of the electrical equipment, and the performance of components in the battery pack (such as switches).
  • FIG. 13 shows a flow chart of a specific embodiment of parallel charging of battery packs.
  • the first battery pack performs discharge in parallel, including: closing a discharge switch on a discharge loop of the first battery pack. Alternatively, including: closing a charge switch and a discharge switch on a discharge loop of the first battery pack.
  • the first battery pack may transmit circulating current to the other battery packs through the circulating current paths of the other battery packs.
  • the battery pack in order to reduce the circulating current, performs discharge parallel connection and also includes the operation of the circulating current path.
  • the electric device is in the discharge state
  • the battery pack BT1 is not incorporated (the battery pack BT1 can represent a battery pack that is not discharged in parallel), and the battery pack BT2 is incorporated (the battery pack BT2 can represent one or more battery packs that are discharged in parallel).
  • FIG14a for the status of the battery packs BT1 and BT2.
  • the battery pack BT1 can perform discharge parallel connection in the following four stages:
  • Phase 1 Disconnect the circulation path of BT2.
  • the conduction and disconnection of the circulation path in the discharge circuit can be controlled by the charging switch.
  • Disconnecting the circulation path can be disconnecting the charging switch in the discharge circuit.
  • disconnecting the circulation path of BT2 includes disconnecting the charging switch CHG3 of BT2, so that the battery pack BT1 cannot transmit the circulation current to the battery pack BT2 through the circulation path, and the circulation current can be further reduced.
  • Figure 14b Please refer to Figure 14b.
  • the battery pack BT2 disconnects the charging switch on the discharge circuit of the battery pack BT2 in response to receiving a parallel request instruction (in this embodiment, receiving a parallel request instruction sent by BT1).
  • a parallel request instruction in this embodiment, receiving a parallel request instruction sent by BT1.
  • BT2 is in a state of being discharged in parallel.
  • the circulation path of BT2 is first disconnected, and then the discharge path of BT1 is turned on.
  • the switches on the charging circuit and the discharging circuit of each battery pack can be considered to be in a disconnected state, and the circulation path of each battery pack is in a disconnected state.
  • stage 1 can be omitted, and stage 1 can be directly skipped to execute stage 2.
  • the circulation path of the second battery pack BT2 can be disconnected by executing the operation of stage 1.
  • Phase 2 Turn on the discharge path of BT1.
  • the conduction and disconnection of the discharge path in the discharge circuit can be controlled by the discharge switch, and the conduction discharge path can be the discharge switch in the closed discharge circuit.
  • the discharge path of conducting BT1 includes closing the discharge switch DSG1 of BT1.
  • the battery pack BT1 can be charged through the discharge path, please refer to FIG14c.
  • the pre-discharge switch before closing the discharge switch, may be closed first, and then the pre-discharge switch may be opened after a certain time interval, and the discharge switch may be closed.
  • the battery pack BT1 in order to confirm that the circulation path of the parallel battery pack is in a disconnected state and reduce the circulation, closes the discharge switch on the discharge loop in response to receiving the second information.
  • the second information is used to indicate that the circulation path of the battery pack BT2 has been disconnected. In this embodiment of the present application, it may be that the charging switch on the discharge loop of the battery pack BT2 is in a disconnected state.
  • Phase 3 Turn on the circulation path of BT1 and BT2.
  • the conducting circulation path can be realized by closing the charging switch in the discharge loop.
  • the conducting circulation path of BT1 includes closing the charging switch CHG1
  • the conducting circulation path of BT2 includes closing the charging switch CHG3 of BT2, please refer to FIG. 14d.
  • stage 3 may also include: in response to the operating data of the battery pack BT1 satisfying the second condition, closing the charging switch on the discharge circuit of the battery pack BT1, and/or, in response to the operating data of the battery pack BT2 satisfying the second condition, closing the charging switch on the discharge circuit of the battery pack BT2.
  • the second condition is used to indicate the condition for limiting the circulating current, and may include at least one of the following conditions:
  • the discharge current of the battery pack is greater than or equal to the second current threshold.
  • the discharge current of the battery pack is less than the second current threshold, and the voltage difference between the voltage of the battery pack and the third voltage is within the third voltage difference range.
  • the internal resistance of the battery pack is considered to be roughly the same. Then, the larger the discharge current, the larger the voltage difference between the battery pack BT1 and the load, and the larger the battery pack voltage.
  • the discharge current of the battery pack BT1 is greater than or equal to the second current threshold, the voltage difference between the battery pack and the load is large, and the voltage of the battery pack is large.
  • the battery pack with a large voltage needs to be discharged first, because discharging the battery pack with a large voltage first can reduce the voltage difference between the battery packs. Therefore, it can be considered that the battery pack BT1 meets the circulation limit conditions.
  • the discharge current of battery pack BT1 is less than the second current threshold, the voltage difference between the battery pack and the load is small, the voltage of the battery pack is small, and the voltage of the battery pack is closer to the load.
  • Other battery packs may discharge to battery pack BT1 (i.e., circulating current occurs), and at this time, further judgment can be made in combination with other electrical parameters.
  • the discharge current of the battery pack BT1 is greater than or equal to the second current threshold, it can be considered that the first battery pack meets the circulation restriction condition, and its circulation path can be turned on to close the charging switch on the discharge loop.
  • the discharge current of the battery pack BT1 is less than the second current threshold, it can be further determined whether the voltage difference between the battery pack BT1 and the third voltage is within the third voltage difference range. If the voltage difference is within the third voltage difference range, the voltage difference between the battery packs is small, and the risk of large circulation is small.
  • the circulation path can be turned on and the charging switch on the discharge circuit of the battery pack BT1 can be closed.
  • large circulation current means that the circulation current value between the battery pack BT1 and other battery packs is larger
  • small circulation current means that the circulation current value between the battery pack BT1 and other battery packs is smaller
  • the charging switch on the discharge loop is not closed. In some embodiments, the judgment may be made again after a period of time.
  • the third voltage may be an average voltage of each battery pack, or a maximum voltage or a minimum voltage of each battery pack. In some embodiments, the third voltage is the maximum voltage of each battery pack.
  • the third pressure difference range can be set according to specific application conditions, for example, according to the maximum charging current and/or time allowed for the battery cells in the battery pack, the model and specifications of the charger, the overcurrent capacity of the connector or connecting harness, the withstand voltage and overcurrent capacity of the electrical equipment, and the performance of the components (such as switches) in the battery pack.
  • the third pressure difference range and the first pressure difference range can be the same or different.
  • the third pressure difference range is within the first pressure difference range, and the range of the third pressure difference range is smaller than the first pressure difference range.
  • the second current threshold can be set according to the specific application, for example, according to the maximum charging current and/or time allowed by the battery cells in the battery pack, the model and specification of the charger, the overcurrent capacity of the connector or connecting harness, the withstand voltage and overcurrent capacity of the electrical equipment, and the performance of the components (such as switches) in the battery pack.
  • the second current threshold can be 2A.
  • Phase 4 If there is a risk of circulating current, disconnect the discharge circuit of BT1, or just disconnect the circulating current path. If there is no risk of circulating current, complete the charging and parallel operation.
  • a step of judging the circulating current risk is also included. If there is a circulating current risk, the charging switch and the discharging switch on the discharge circuit of the battery pack BT1 are disconnected, or only the charging switch can be disconnected. If there is no circulating current risk, the circulating current path of the battery pack BT1 is kept open. In other embodiments, the battery pack discharge in parallel may not include stage 4.
  • Whether there is a circulation risk between battery packs can be determined by determining whether the battery pack meets a second circulation condition, wherein the second circulation condition includes that the absolute value of the difference between the current rate of the first battery pack and the second current rate is greater than or equal to a second current rate threshold.
  • the second current rate is the maximum discharge current rate among the battery packs connected in parallel.
  • the discharge currents of the battery packs connected in parallel can be obtained, and then the maximum discharge current rate is selected as the second current rate.
  • the embodiment of the present application uses the maximum discharge current rate (i.e., the second current rate) in each battery pack connected in parallel as a benchmark, and uses the absolute value of the difference between the current rate of the first battery pack and the second current rate as a judgment condition, which can well identify situations where there is a risk of large circulation.
  • the discharge current can be set as negative and the charge current as positive.
  • the current magnification of the battery pack BT1 is positive
  • the second current magnification is negative
  • the absolute value of the difference between the two is large.
  • the current magnification of the battery pack BT1 and the first current magnification are both negative. If the current magnification of the battery pack BT1 differs greatly from the first current magnification, the absolute value of the difference between the two is also large.
  • the discharge current may be positive and the charge current may be negative.
  • the presence of a circulating current risk may also be determined by the discharge current value.
  • the first circulating current condition may also include: the absolute value of the difference between the current of the first battery pack and the second current is greater than or equal to the second current threshold.
  • the second current is the maximum discharge current of each battery pack connected in parallel.
  • the second current threshold can be set according to specific application conditions, for example, according to the large circulating current tolerance of the battery pack.
  • FIG. 15 shows a flow chart of a specific embodiment of parallel charging of battery packs.
  • the battery pack parallel connection method also includes detecting the on/off state of a charging switch and/or a discharging switch on a charging circuit of the battery pack and sending a third message, and/or detecting the on/off state of a charging switch and/or a discharging switch on a discharging circuit of the battery pack and sending a fourth message.
  • the third information is used to indicate the on/off state of the charging switch and/or the discharging switch on the charging circuit
  • the fourth information is used to indicate the on/off state of the charging switch and/or the discharging switch on the discharging circuit.
  • the third information and the fourth information may be referred to as checkback information.
  • the BMS after sending a closing or opening signal to the charging switch or the discharging switch, the BMS will detect the on-off state of the charging switch or the discharging switch, and send the on-off state to other battery packs.
  • the third information or the fourth information indicating the on-off state of the switch other battery packs can know the on-off state of the switch of the battery pack that sent the information, clarify the specific stage of the battery pack in the parallel process, and provide a reference for the next stage of operation.
  • each battery pack can identify the current stage as the first stage through the received feedback information and can enter the second stage (closing the charging switch on the BT1 charging circuit).
  • Each battery pack can identify the current stage as the second stage through the received feedback information and can enter the third stage (closing the discharging switches on the charging circuits of BT1 and BT2).
  • Each battery pack can identify the current stage as the third stage through the received feedback information and can enter the fourth stage.
  • a delay time is set for the on/off of the charging switch and/or the discharging switch. For example, after the BMS sends a control signal to disconnect or close the charging switch and/or the discharging switch, a period of time (for example, 1s) is extended to ensure that the switch is normally closed or disconnected. It can be understood that in the embodiment of the present application where there is a detection of the on/off of the charging switch and/or the discharging switch, it is not necessary to set a delay time, which is beneficial to shorten the parallel connection time of the battery pack.
  • FIG16 takes charging as an example and shows a flow chart of an embodiment of a battery pack parallel connection method including a backcheck step.
  • the switch backcheck operation during discharge can be referred to FIG16 and will not be described in detail here.
  • An embodiment of the present application also provides a storage medium storing computer executable instructions, which are executed by one or more processors, such as a processor 11 in Figure 7, so that the one or more processors can execute the battery pack parallel connection method in any of the above method embodiments, for example, execute method steps 101 and 102 in Figure 8 described above.
  • the embodiment of the present application also provides a computer program product, the computer program product includes a computer program stored on a non-volatile computer-readable storage medium, the computer program includes program instructions, when the program instructions are executed by a machine (such as a BMS), the machine executes the above-mentioned battery pack parallel connection method. For example, execute the method steps 101 and 102 in Figure 8 described above.
  • a machine such as a BMS

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  • Manufacturing & Machinery (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Power Engineering (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

Selon des modes de réalisation, la présente invention se rapporte au domaine technique des batteries, et concerne, par exemple, un procédé de connexion en parallèle de blocs-batteries, un système de gestion de batteries, un bloc-batterie, un dispositif électrique et un support de stockage. Le procédé de connexion en parallèle de blocs-batteries consiste à : en réponse au fait qu'un premier bloc-batterie satisfait une première condition de connexion en parallèle et est dans un état de charge, commander l'ouverture d'un interrupteur sur une boucle de décharge et la réalisation d'une charge en parallèle sur le premier bloc-batterie ; ou, en réponse au fait que le premier bloc-batterie satisfait la première condition de connexion en parallèle et est dans un état de décharge, commander l'ouverture d'un interrupteur sur une boucle de charge et la réalisation d'une décharge en parallèle sur le premier bloc-batterie. Selon les modes de réalisation de la présente invention, lorsque des blocs-batteries sont chargés, la boucle de décharge est déconnectée, et lorsque des blocs-batteries sont déchargés, la boucle de charge est déconnectée. De cette manière, des courants de circulation générés entre les blocs-batteries dans la boucle de décharge pendant la charge peuvent être réduits, et des courants de circulation générés dans la boucle de charge pendant la décharge peuvent également être réduits, ce qui permet de réduire les courants de circulation entre les blocs-batteries et d'améliorer la sécurité des blocs-batteries.
PCT/CN2022/133568 2022-11-22 2022-11-22 Procédé de connexion en parallèle de blocs-batteries, système de gestion de batteries, bloc-batterie et dispositif électrique WO2024108401A1 (fr)

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PCT/CN2022/133568 WO2024108401A1 (fr) 2022-11-22 2022-11-22 Procédé de connexion en parallèle de blocs-batteries, système de gestion de batteries, bloc-batterie et dispositif électrique

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PCT/CN2022/133568 WO2024108401A1 (fr) 2022-11-22 2022-11-22 Procédé de connexion en parallèle de blocs-batteries, système de gestion de batteries, bloc-batterie et dispositif électrique

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013179454A1 (fr) * 2012-05-31 2013-12-05 パイオニア株式会社 Dispositif de commande de charge/décharge
CN206059499U (zh) * 2016-09-28 2017-03-29 惠州市蓝微新源技术有限公司 多簇电池组并联系统
CN206389154U (zh) * 2017-01-16 2017-08-08 祁国俊 电池包充放电控制电路及电动车动力电池系统
CN112838648A (zh) * 2021-03-05 2021-05-25 杭州惟领科技有限公司 一种低压户用储能系统动态并机电路及方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013179454A1 (fr) * 2012-05-31 2013-12-05 パイオニア株式会社 Dispositif de commande de charge/décharge
CN206059499U (zh) * 2016-09-28 2017-03-29 惠州市蓝微新源技术有限公司 多簇电池组并联系统
CN206389154U (zh) * 2017-01-16 2017-08-08 祁国俊 电池包充放电控制电路及电动车动力电池系统
CN112838648A (zh) * 2021-03-05 2021-05-25 杭州惟领科技有限公司 一种低压户用储能系统动态并机电路及方法

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