Parallel system of battery modules and energy storage device

Abstract

The application discloses a parallel connection system of a battery module and an energy storage device. The parallel connection system comprises a controller and a plurality of battery modules. Each battery module comprises a battery, a battery management unit, a discharging switch and a charging switch. The battery is connected to the discharging switch and the charging switch in sequence. The battery management unit is connected to control ends of the discharging switch and the charging switch. The discharging switch is used for controlling discharging of the battery module, and the charging switch is used for controlling charging of the battery module. The plurality of battery modules are connected in parallel. The controller is connected to each of the plurality of battery modules in communication. The controller is used for transmitting battery data between different battery modules. Any battery management unit in the parallel connection system is used for receiving the battery data from the controller and controlling the discharging switch and the charging switch according to the battery data. The application can accelerate the voltage equalization speed between the battery modules in the parallel connection system.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, specifically to a parallel system of battery modules and an energy storage device. Background Technology

[0002] Currently, to increase the battery capacity of energy storage devices, two or more battery modules are generally connected in parallel to form a parallel system for charging and discharging. However, differences exist between the various battery parameters of the battery modules in a parallel system, leading to voltage imbalances between the modules. This creates a bottleneck effect in the parallel system, affecting its charging and discharging performance.

[0003] In existing technologies, equalizing resistors are generally used to dissipate the power of the higher voltage battery modules, so that the voltage between the battery modules in the parallel system can be balanced. However, the balancing speed is slow and takes a long time. Utility Model Content

[0004] In view of this, this application provides a parallel battery module system and energy storage device to accelerate the voltage equalization speed among the battery modules in the parallel system. The technical solution of this application is as follows:

[0005] This application provides a parallel system for battery modules, the parallel system including a controller and multiple battery modules. Each battery module includes a battery, a battery management unit, a discharge switch, and a charging switch. The battery is sequentially connected to the discharge switch and the charging switch. The battery management unit is connected to the control terminals of the discharge switch and the charging switch. The discharge switch controls the discharge of the battery module, and the charging switch controls the charging of the battery module. The multiple battery modules are connected in parallel, and the controller is communicatively connected to each of the multiple battery modules. The controller is used to transmit battery data between different battery modules. Any of the battery management units in the parallel system is used to: receive the battery data from the controller and control the discharge switch and the charging switch according to the battery data.

[0006] In one embodiment of this application, the parallel system further includes a charging interface and a discharging interface; when the parallel system discharges through the discharging interface, the discharging switch of the low-voltage battery module is turned on and the charging switch is turned off, while the discharging switch and the charging switch of the high-voltage battery module are turned on. The low-voltage battery module is the one with the lower voltage among the plurality of battery modules, and the high-voltage battery module is the one with the higher voltage among the plurality of battery modules. When the parallel system charges through the charging interface, the discharging switch and the charging switch of the low-voltage battery module are turned on, while the discharging switch of the high-voltage battery module is turned off and the charging switch is turned on.

[0007] In one embodiment of this application, when the voltages of all the battery modules in the parallel system are balanced, the discharge switch and the charging switch of the low-voltage battery module and the high-voltage battery module are turned on; when the parallel system enters dormancy after being fully charged, the discharge switch of all the battery modules is turned on and the charging switch is turned off; when the parallel system enters dormancy during discharge, the discharge switch of the high-voltage battery module is turned off.

[0008] In one embodiment of this application, the parallel system further includes a charger for electrical connection to the charging interface. When the charger is connected during discharge of the parallel system, the discharge switch and the charging switch of the low-voltage battery module are turned on, and the discharge switch and the charging switch of the high-voltage battery module are turned off. When the charger is removed during charging of the parallel system, the charging switch of the low-voltage battery module is turned off, and the discharge switch of the high-voltage battery module is turned on.

[0009] In one embodiment of this application, the battery management unit is a BMS, and the controller includes an MCU.

[0010] In one embodiment of this application, the battery includes a plurality of cells connected in parallel or in series.

[0011] In one embodiment of this application, the charging switch and the discharging switch are MOS field-effect transistors.

[0012] In one embodiment of this application, when the parallel system discharges through the discharge interface and the battery management unit of any of the battery modules cannot receive the battery data of the other battery module, the discharge switch of the low-voltage battery module is turned on and the charging switch is turned off, while the discharge switch and the charging switch of the high-voltage battery module are turned off.

[0013] In one embodiment of this application, the battery module further includes a pre-discharge circuit, which is connected to the battery, and the battery management unit is connected to the control terminal of the pre-discharge circuit; any of the battery management units in the parallel system is also used to control the pre-discharge circuit to be turned on for a preset time before the discharge switch is turned on, and the battery module discharges to the outside through the pre-discharge circuit.

[0014] A second aspect of this application provides an energy storage device, the energy storage device including a parallel interface and the parallel system, the parallel interface being connected to the parallel system, and the parallel interface being used to connect to another independent battery module.

[0015] The parallel system of this application transmits battery data between each battery module through the controller, so that the battery management unit of each battery module can determine the high and low voltage status of its battery module by comparing all battery data, and control the discharge switch and charging switch according to the high and low voltage status, thereby accelerating the voltage equalization speed between the battery modules in the parallel system. Attached Figure Description

[0016] Figure 1 This is a schematic block diagram of a parallel system of battery modules provided in an embodiment of this application.

[0017] Figure 2 This is a schematic block diagram of a second type of parallel battery module system provided in the embodiments of this application.

[0018] Figure 3 This is a circuit diagram of a battery module provided in an embodiment of this application.

[0019] Figure 4 This is a circuit diagram of a button circuit provided in an embodiment of this application.

[0020] Figure 5 This application also provides a schematic block diagram of an energy storage device. Detailed Implementation

[0021] It should be noted that in the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence.

[0022] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0023] Currently, to increase the battery capacity of energy storage devices, two or more battery modules are generally connected in parallel to form a parallel system for charging and discharging. However, differences exist between the various battery parameters of the battery modules in a parallel system, leading to voltage imbalances between the modules. This creates a bottleneck effect in the parallel system, affecting its charging and discharging performance.

[0024] In existing technologies, equalizing resistors are generally used to dissipate the power of the higher voltage battery modules, so that the voltage between the battery modules in the parallel system can be balanced. However, the balancing speed is slow and takes a long time.

[0025] This application provides a parallel battery module system and energy storage device to accelerate the voltage balancing speed among the various battery modules in the parallel system.

[0026] Please refer to Figure 1 , Figure 1 This is a schematic block diagram of a parallel battery module system provided in an embodiment of this application. The parallel system 100 includes a controller 110 and multiple battery modules 120 (two battery modules 120 are shown as an example in the figure).

[0027] In this embodiment, the battery module 120 includes a battery management unit 121, a discharge switch 122, a charging switch 123, and a battery 124. The battery 124 is sequentially connected to the discharge switch 122 and the charging switch 123. For example, the battery 124 is sequentially connected to the positive terminal of the battery module 120 through the discharge switch 122 and the charging switch 123. The battery management unit 121 is connected to the control terminals of the discharge switch 122 and the charging switch 123.

[0028] The discharge switch 122 controls the discharge of the battery module 120, and the charging switch 123 controls the charging of the battery module 120. The battery 124, connected to the discharge switch 122 and the charging switch 123, forms the main circuit for charging and discharging the battery module 120. The battery management unit 121 can be connected to any node in the main circuit to detect the battery data of the battery module 120. This battery data includes battery voltage, battery current, battery internal resistance, battery temperature, battery capacity, and the number of charge / discharge cycles, etc., which are not limited here. The battery management unit 121 is also connected to the control terminals of the discharge switch 122 and the charging switch 123.

[0029] In some embodiments, the battery 124 includes multiple cells, which can be connected in series or in parallel to form the battery 124; no limitation is made here. The discharge switch 122 includes a MOSFET, and the charging switch 123 includes a MOSFET.

[0030] In this parallel system 100, multiple battery modules 120 are connected in parallel. The controller 110 is communicatively connected to each of the multiple battery modules 120. For example, the parallel system 100 includes a positive bus and a negative bus, and each battery module 120 includes a positive terminal and a negative terminal. The positive terminal of each battery module 120 is connected to the positive bus, and the negative terminal of each battery module 120 is connected to the negative bus, thereby connecting multiple battery modules 120 in parallel. The controller 110 can be directly connected to the battery management unit 121 of each battery module 120, thereby realizing the communication connection between the controller and the battery module 120.

[0031] The controller 110 is used to transmit battery data between different battery modules 120. For example, in a parallel system 100 including battery module A and battery module B, the controller 110 can obtain battery data 'a' from battery module A through the battery management unit 121 of battery module A and transmit battery data 'a' to battery module B; similarly, the controller 110 can obtain battery data 'b' from battery module B through the battery management unit 121 of battery module B and transmit battery data 'b' to battery module A. Similarly, when the parallel system 100 includes two or more battery modules 120, the battery management unit 121 of battery module 120 can obtain battery data from the other battery modules 120 in the system through the controller 110.

[0032] In the parallel system 100, any battery management unit 121 is used to: receive battery data from the controller 110, and control the discharge switch 122 and the charging switch 123 according to the battery data. That is, the battery management unit 121 can determine the high and low voltage status of the battery module 120 it is in by comparing all battery data, and control the discharge switch 122 and the charging switch 123 according to the high and low voltage status, thereby accelerating the voltage equalization speed among the various battery modules 120 in the parallel system 100.

[0033] For example, after comparing all battery data, the battery management unit 121 can control the discharge switch 122 to turn off when it determines that the battery module 120 is a low-voltage battery module 120, thus preventing the battery module 120 from continuing to discharge. When it determines that the battery module 120 is a high-voltage battery module 120, it can control the discharge switch 122 to turn on, allowing the battery module 120 to discharge, ultimately making the voltage between the various battery modules 120 in the parallel module tend to be balanced.

[0034] In this embodiment, the parallel system 100 further includes a charging interface and a discharging interface. When the parallel system 100 discharges through the discharging interface, the discharging switch 122 of the low-voltage battery module is turned on and the charging switch 123 is turned off, while the discharging switch 122 and the charging switch 123 of the high-voltage battery module are turned on. The low-voltage battery module is the one with the lowest voltage among the multiple battery modules 120, and the high-voltage battery module is the one with the highest voltage among the multiple battery modules 120. When the parallel system 100 charges through the charging interface, the discharging switch 122 and the charging switch 123 of the low-voltage battery module are turned on, while the discharging switch 122 of the high-voltage battery module is turned off and the charging switch 123 is turned on.

[0035] For example, any battery management unit 121 in the parallel system 100 is used to determine whether the corresponding battery module 120 is a low-voltage battery module 120 or a high-voltage battery module 120 based on battery data. When the parallel system 100 is discharging, the battery management unit 121 controls the discharge switch 122 of the low-voltage battery module 120 to be turned on and the charging switch 123 to be turned off, and controls the discharge switch 122 and the charging switch 123 of the high-voltage battery module 120 to be turned on.

[0036] In some embodiments, when the parallel system 100 supplies power to an external load, the discharge switch 122 and the charging switch 123 of the existing battery module 120 are both turned on. If a new battery module 120 is connected to the parallel system 100 at this time, the voltage between the battery modules 120 becomes unbalanced, resulting in a low-voltage battery module 120 with a lower voltage and a high-voltage battery module 120 with a higher voltage. In this case, the battery management unit 121 of the low-voltage battery module 120 controls the discharge switch 122 to turn on and the charging switch 123 to turn off, while the battery management unit 121 of the high-voltage battery module 120 controls the discharge switch 122 and the charging switch 123 to turn on.

[0037] For example, when the parallel system 100 is connected to a charger for charging, the discharge switch 122 and the charging switch 123 of the existing battery module 120 are both turned on. At the same time, when a new battery module 120 is connected, the voltage between the battery modules 120 will also be unbalanced, with a low-voltage battery module 120 having a lower voltage and a high-voltage battery module 120 having a higher voltage. Then, the discharge switch 122 and the charging switch 123 of the battery management unit 121 of the low-voltage battery module 120 are turned on, and the battery management unit 121 of the high-voltage battery module 120 controls the discharge switch 122 to turn off and the charging switch 123 to turn on.

[0038] During the discharge of the parallel system 100, the controller 110 can transmit discharge commands to the battery management units 121 of each battery module 120. During the charging of the parallel system 100, the controller 110 can transmit charging commands to the battery management units 121 of each battery module 120. Simultaneously with transmitting charging or discharging commands, the controller 110 begins to exchange battery data between the various battery modules 120.

[0039] In some embodiments, when the voltages of all battery modules 120 in the parallel system 100 are balanced, the discharge switch 122 and the charging switch 123 of the low-voltage battery module and the high-voltage battery module are turned on. For example, any battery management unit 121 in the parallel system 10 is also used to control the discharge switch 122 and the charging switch 123 to turn on when it is determined from battery data that the voltages of two battery modules 120 are balanced. That is, after determining that the voltages of all battery modules 120 are balanced, all battery management units 121 in the parallel system 100 control the corresponding discharge switch 122 and charging switch 123 to turn on, so that the parallel system 100 can exert the optimal charging and discharging advantages.

[0040] In some embodiments, when the parallel system 100 enters a sleep state after being fully charged, the discharge switch 122 and the charging switch 123 of all battery modules 120 are turned off. For example, any battery management unit 121 in the parallel system 100 is also used to control the discharge switch 122 to be turned on and the charging switch 123 to be turned off when the parallel system 100 enters a sleep state after being fully charged. That is, after determining that all battery modules 120 are fully charged, all battery management units 121 in the parallel system 100 control the corresponding charging switch 123 to be turned off, so as to prevent the parallel system 100 from being overcharged when the charger is plugged in again.

[0041] In some embodiments, when the parallel system 100 enters a dormant state during discharge, the discharge switch 122 of the high-voltage battery module is turned on and the charging switch 123 is turned off. For example, any battery management unit 121 in the parallel system 100 is also used to control the discharge switch 122 of the high-voltage battery module 120 to be turned off when the parallel system 100 enters a dormant state during discharge, so as to ensure that the low-voltage battery module 120 in the parallel system 100 will not be unable to enter a dormant state due to front-end characteristics.

[0042] In some embodiments, the parallel system 100 further includes a charger for connecting to a charging interface. When the charger is connected during the discharge of the parallel system 100, the discharge switch 122 and the charging switch 123 of the low-voltage battery module are turned on, and the discharge switch 122 of the high-voltage battery module is turned off and the charging switch 123 is turned on.

[0043] For example, in the parallel system 100, any battery management unit 121 is also used to control the discharge switch 122 and charging switch 123 of the low-voltage battery module 120 to be turned on when a charger is connected during the discharge of the parallel system 100, and to control the discharge switch 122 of the high-voltage battery module 120 to be turned off and the charging switch 123 to be turned on, thereby ensuring that the charging speed of the low-voltage battery module 120 in the parallel system 100 is higher than that of the high-voltage battery module 120, thereby accelerating the voltage balance among the battery modules 120 in the parallel system 100.

[0044] In some embodiments, when the charger is removed during charging of the parallel system 100, the charging switch 123 of the low-voltage battery module is turned off, and the discharging switch 122 of the high-voltage battery module is turned on. For example, any battery management unit 121 in the parallel system 100 is also configured to control the charging switch 123 of the low-voltage battery module 120 to be turned off and the discharging switch 122 of the high-voltage battery module 120 to be turned on when the charger is removed during charging of the parallel system 100. That is, after the charger is removed, it is ensured that the discharge rate of the high-voltage battery module 120 in the parallel system 100 is higher than that of the low-voltage battery module 120, thereby accelerating the voltage equalization among the battery modules 120 in the parallel system 100.

[0045] In some embodiments, when the parallel system 100 discharges through the discharge interface and the battery management unit 121 of any battery module 120 cannot receive battery data from the other battery module 120, the discharge switch 122 of the low-voltage battery module is turned on and the charging switch 123 is turned off, and the discharge switch 122 and the charging switch 123 of the high-voltage battery module 120 are turned off.

[0046] For example, any battery management unit 121 in the parallel system 100 is also used to control the discharge switch 122 to be turned on and the charging switch 123 to be turned off when the parallel system 100 is discharging and the battery data of another battery module 120 cannot be received. If it is a low-voltage battery module 120, it controls the discharge switch 122 and the charging switch 123 to be turned off. If it is a high-voltage battery module 120, it controls the discharge switch 122 and the charging switch 123 to be turned off.

[0047] Please refer to Figure 2 , Figure 2 This is a schematic block diagram of a parallel system 100 for a second type of battery module 120 provided in an embodiment of this application. Figure 1 Compared to the parallel system 100 shown, Figure 2 The parallel system 100 shown differs in that the battery module 120 also includes a pre-discharge circuit 125. The pre-discharge circuit 125 is connected to the battery 124, and the battery management unit 121 is connected to the control terminal of the pre-discharge circuit 125.

[0048] In this embodiment of the application, any battery management unit 121 in the parallel system 100 is also used to control the pre-discharge circuit 125 to be turned on for a preset time before the discharge switch 122 is turned on, so that the battery module 120 discharges to the outside through the pre-discharge circuit 125, thereby reducing the voltage surge after the discharge switch 122 is turned on.

[0049] Please refer to Figure 3 , Figure 3 The present application provides a circuit diagram of a battery module 120, wherein the discharge switch 122 in the battery module 120 includes a first switch transistor Q1 and a first resistor R1, the charging switch 123 includes a second switch transistor Q2 and a second resistor R2, and the pre-discharge circuit 125 includes a third switch transistor Q3 and a third resistor R1.

[0050] In this configuration, the first terminal of the first switch Q1 is connected to the positive terminal B+ of the battery 124 in the battery module 120, and the second terminal of the first switch Q1 is connected to the first terminal of the second switch Q2. The second terminal of the second switch Q2 is connected to the bus P+ of the parallel system 100. The first terminal of the third switch Q3 is connected to the positive terminal B+ of the battery 124 in the battery module 120, and the second terminal of the third switch Q3 is connected to the bus P+ of the parallel system 100.

[0051] The control terminal of the first switch Q1 is connected to the battery management unit 121 through the first resistor R1, the control terminal of the second switch Q2 is connected to the battery management unit 121 through the second resistor R2, and the control terminal of the third switch Q3 is connected to the battery management unit 121 through the third resistor R3.

[0052] In some embodiments, the parallel system 100 further includes a button circuit 130 connected to a controller 110. The button circuit 130 is used to transmit a control signal to the controller 110 when triggered, so that the controller 110 controls the parallel system 100 to power on or enter a sleep state. Figure 4 As shown, the button circuit 130 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a diode D1, and a fourth switching transistor Q4.

[0053] The fourth resistor R4 is connected to the control terminal of the fourth switch Q4. The negative terminal of diode D1 is connected to the control terminal of the fourth switch Q4, and the positive terminal of diode D1 is connected to the second terminal of the fourth switch Q4 and grounded. The fifth resistor R5 is connected in parallel with diode D1. The first terminal of the fourth switch Q4 is connected to the controller 110, and the first terminal of the fourth switch Q4 is also grounded through the sixth resistor. The first terminal of the fourth switch Q4 also receives the supply voltage through the seventh resistor R7.

[0054] Please refer to Figure 5 , Figure 5This application also provides a schematic block diagram of an energy storage device. The energy storage device 10 includes a parallel interface and a parallel system 100. The parallel interface 101 is connected to the parallel system 100 and is used to connect to another independent battery module 120.

[0055] It is understood that the beneficial effects of the energy storage device 10 can be referred to the beneficial effects of the parallel system 100 in the foregoing embodiments, and will not be repeated here.

[0056] The above embodiments are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.

Claims

1. A parallel connection system for battery modules, characterized in that, The parallel system includes a controller and multiple battery modules. Each battery module includes a battery, a battery management unit, a discharge switch, and a charging switch. The battery is connected in sequence to the discharge switch and the charging switch. The battery management unit is connected to the control terminals of the discharge switch and the charging switch. The discharge switch is used to control the discharge of the battery module, and the charging switch is used to control the charging of the battery module. The plurality of battery modules are connected in parallel, and the controller is communicatively connected to each of the plurality of battery modules. The controller is used to transmit battery data between different battery modules; In the parallel system, any of the battery management units is used to: receive battery data from the controller and control the discharge switch and the charging switch according to the battery data.

2. The parallel system as described in claim 1, characterized in that, The parallel system also includes a charging interface and a discharging interface; When the parallel system discharges through the discharge interface, the discharge switch of the low-voltage battery module is turned on and the charging switch is turned off, while the discharge switch and charging switch of the high-voltage battery module are turned on. The low-voltage battery module is the one with the lower voltage among the plurality of battery modules, and the high-voltage battery module is the one with the higher voltage among the plurality of battery modules. When the parallel system is charged through the charging interface, the discharge switch and the charging switch of the low-voltage battery module are turned on, and the discharge switch and the charging switch of the high-voltage battery module are turned off.

3. The parallel system as described in claim 2, characterized in that, When the voltages of all the battery modules in the parallel system are balanced, the discharge switch and the charging switch of the low-voltage battery module and the high-voltage battery module are turned on. When the parallel system enters sleep mode after being fully charged, the discharge switches of all battery modules are turned on and the charging switches are turned off. When the parallel system enters a dormant state during discharge, the discharge switch of the high-voltage battery module is turned off.

4. The parallel system as described in claim 2, characterized in that, The parallel system also includes a charger, which is used to be electrically connected to the charging interface. When the charger is connected during the discharge of the parallel system, the discharge switch and the charging switch of the low-voltage battery module are turned on, and the discharge switch and the charging switch of the high-voltage battery module are turned off. When the charger is removed during the parallel system charging, the charging switch of the low-voltage battery module is turned off, and the discharging switch of the high-voltage battery module is turned on.

5. The parallel system as described in claim 2, characterized in that, When the parallel system discharges through the discharge interface, and the battery management unit of any battery module cannot receive the battery data of the other battery module, the discharge switch of the low-voltage battery module is turned on and the charging switch is turned off, while the discharge switch and the charging switch of the high-voltage battery module are turned off.

6. The parallel system as described in claim 2, characterized in that, The battery module also includes a pre-discharge circuit, which is connected to the battery, and the battery management unit is connected to the control terminal of the pre-discharge circuit. In the parallel system, any of the battery management units is also used to control the pre-discharge circuit to be turned on for a preset time before the discharge switch is turned on, so that the battery module can discharge to the outside through the pre-discharge circuit.

7. The parallel system as described in any one of claims 1 to 6, characterized in that, The battery management unit is a BMS, and the controller includes an MCU.

8. The parallel system as described in any one of claims 1 to 6, characterized in that, The battery comprises multiple cells connected in parallel or in series.

9. The parallel system as described in any one of claims 1 to 6, characterized in that, The charging switch and the discharging switch are MOSFETs.

10. An energy storage device, characterized in that, The energy storage device includes a parallel interface and a parallel system as described in any one of claims 1 to 9, wherein the parallel interface is connected to the parallel system and is used to connect to another independent battery module.

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