Battery pack, electric energy device and energy storage system

Abstract

The present application relates to a battery pack, an electric energy device and an energy storage system. The battery pack comprises a battery, a switch group and an electric energy interface, wherein the switch group is electrically connected to both the battery and the electric energy interface; the switch group is used for controlling the battery to deliver a direct current to the electric energy interface; and the switch group is used for alternately switching states under the control of the battery pack to change the direction of the current flowing from the battery to the electric energy interface, so as to output an alternating current to the electric energy interface. In the technical solution of the present application, the functionality of the existing switch group is enhanced, so that the switch group can perform alternating-current / direct-current conversion while completing direct-current power supply. In this way, the problem of grid connection between the battery pack and an energy storage power station is solved without adding additional electrical elements and without providing an extra inverter, thereby reducing the cost of grid connection between the battery pack and the energy storage power station.

Description

Battery pack, electric energy device and energy storage system

[0001] Cross Reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202410878616.2 filed on June 28, 2024, and entitled "Battery pack, electric energy device and energy storage system", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of battery, in particular to a battery pack, an electric energy device and an energy storage system. BACKGROUND

[0004] During the vehicle use, the performance of the battery pack will gradually decline. Generally, when the battery capacity is attenuated to less than 80% of the initial capacity, the battery pack will be retired. Although these retired battery packs cannot be used in high energy demand occasions such as automobiles, their remaining capacity can still meet the requirements of low energy demand scenarios such as energy storage and backup power. Therefore, the retired battery packs are usually sent to the energy storage system and continue to be used as energy storage devices.

[0005] In the related art, when the battery pack is connected to the energy storage power station in parallel, an inverter is usually connected to the battery pack to convert the direct current of the battery pack into alternating current required for parallel connection. However, due to the difference in voltage platform of battery packs produced by different manufacturers and vehicle models, different inverters need to be equipped when different battery packs are connected to the energy storage power station in parallel to adapt the current of the battery pack and the energy storage power station. The cost of parallel connection of the battery pack and the energy storage power station is increased. SUMMARY

[0006] The purpose of the present application is to provide a new current determination scheme.

[0007] The purpose of the present application is to provide a battery pack, an electric energy device and an energy storage system, which aims to solve the problem of high cost of parallel connection of battery pack in the related art.

[0008] To achieve the purpose of the present application, in a first aspect, the present application provides a battery pack, comprising a battery, a switch group and an electric energy interface, the switch group is electrically connected with the battery and the electric energy interface respectively;

[0009] The switch group is used to control the battery to deliver direct current to the electric energy interface;

[0010] The switch group is used to reciprocally switch states under the control of the battery pack to change the current direction of the battery flowing to the electric energy interface, so as to output alternating current for the electric energy interface.

[0011] In a possible implementation, the electric energy interface comprises a first interface and a second interface, the switch group has a first state and a second state, and the switch group is configured to reciprocally switch the first state and the second state to enable the electric energy interface to output alternating current;

[0012] In the first state, the battery pack controls the positive electrode of the battery to be connected to the first interface and the negative electrode of the battery to be connected to the second interface.

[0013] In the second state, the battery pack controls the negative electrode of the battery to be connected to the first interface and the negative electrode of the battery to be connected to the second interface.

[0014] In a possible implementation, the switch group comprises a first switch, a second switch, a third switch, and a fourth switch; a first end of the first switch is connected to the positive electrode of the battery, a first end of the second switch, and the first interface; a second end of the first switch is connected to a first end of the third switch;

[0015] a second end of the second switch is connected to a first end of the fourth switch; a second end of the third switch is connected to the negative electrode of the battery, a second end of the fourth switch, and the second interface;

[0016] In the first state, the battery pack controls the first switch and the fourth switch to be closed and controls the second switch and the third switch to be opened.

[0017] In the second state, the battery pack controls the second switch and the third switch to be closed and controls the first switch and the fourth switch to be opened.

[0018] In a possible implementation, the battery pack further comprises an inductor, the inductor is electrically connected to the battery and the switch group respectively; the switch group further has a third state and a fourth state, and the switch group is further configured to reciprocally switch the third state and the fourth state to control the battery to boost power to the electric energy interface.

[0019] In the third state, the battery and the inductor are connected in series to charge the inductor.

[0020] In the fourth state, the battery, the inductor, and the electric energy interface are connected in series to jointly supply power to the electric energy interface.

[0021] In a possible implementation, the electric energy interface includes a first interface and a second interface, and the switch group includes a first switch and a second switch; a first end of the first switch is connected with a positive electrode of the battery and the first interface respectively; a first end of the inductor is connected with a negative electrode of the battery, and a second end of the inductor is connected with a first end of the second switch; a second end of the second switch is connected with the second interface;

[0022] In the third state, the battery pack controls the first switch to be closed and the second switch to be opened;

[0023] In the fourth state, the battery pack controls the first switch and the second switch to be closed.

[0024] In a possible implementation, the battery pack further includes an inductor, the battery includes a first battery and a second battery which are electrically connected with each other, and a negative electrode of the first battery is electrically connected with a positive electrode of the second battery; a first end of the inductor is connected with the negative electrode of the first battery and the positive electrode of the second battery respectively, and a second end of the inductor is connected with the switch group;

[0025] The switch group further has a fifth state and a sixth state, and the switch group is further used to reciprocally switch the fifth state and the sixth state to equalize the first battery and the second battery;

[0026] In the fifth state, the battery pack controls the first battery and the inductor to be connected in series through the switch group;

[0027] In the sixth state, the battery pack controls the first inductor and the second battery to be connected in series through the switch group to charge the second battery through the first inductor.

[0028] In a possible implementation, the switch group includes a first switch and a second switch; a first end of the first switch is connected with a positive electrode of the first battery; a first end of the inductor is connected with a negative electrode of the first battery and a positive electrode of the second battery respectively; a second end of the inductor is connected with a second end of the first switch and a first end of the second switch respectively; and a second end of the second switch is connected with a negative electrode of the second battery;

[0029] In the fifth state, the battery pack controls the first switch to be closed and the second switch to be opened;

[0030] In the sixth state, the battery pack controls the first switch to be opened and the second switch to be closed.

[0031] In a possible implementation, the inductor further includes a first inductor and a second inductor; in the fifth state, the battery pack further controls the second inductor to be connected in series with the second battery through the switch group, so as to charge the second battery through the second inductor.

[0032] In the sixth state, the battery pack further controls the second inductor to be connected in series with the first battery through the switch group, so as to charge the second inductor through the first battery.

[0033] In a possible implementation, the switch group includes a first switch, a second switch, a third switch, and a fourth switch; a first end of the first switch is connected with a positive electrode of the first battery and a first end of the second switch respectively;

[0034] a first end of the first inductor is connected with a negative electrode of the first battery and a positive electrode of the second battery respectively, and a second end of the first inductor is connected with a second end of the first switch and a first end of the third switch respectively;

[0035] a first end of the second inductor is connected with the negative electrode of the first battery and the positive electrode of the second battery respectively, and a second end of the second inductor is connected with a second end of the second switch and a first end of the fourth switch respectively; a second end of the third switch is connected with a negative electrode of the second battery and a second end of the fourth switch respectively;

[0036] In the fifth state, the battery pack controls the first switch and the fourth switch to be closed, and controls the second switch and the third switch to be opened;

[0037] In the sixth state, the battery pack controls the second switch and the third switch to be closed, and controls the first switch and the fourth switch to be opened.

[0038] In a possible implementation, the switch group has a seventh state and an eighth state, and the switch group further reciprocally switches the seventh state and the eighth state, so as to balance the first battery and the second battery;

[0039] In the seventh state, the battery pack controls the second battery to be connected in series with the first inductor through the switch group, so as to charge the first inductor through the second battery;

[0040] In the eighth state, the battery pack controls the first battery to be connected in series with the first inductor through the switch group, so as to charge the first battery through the first inductor.

[0041] In a possible implementation, the switch group comprises a first switch and a second switch; a first end of the first switch is connected with a positive electrode of the first battery; a first end of the inductor is connected with a negative electrode of the first battery and a positive electrode of the second battery respectively; a second end of the inductor is connected with a second end of the first switch and a first end of the second switch respectively; and a second end of the second switch is connected with a negative electrode of the second battery.

[0042] In the seventh state, the battery pack controls the first switch to be turned off and the second switch to be turned on.

[0043] In the eighth state, the battery pack controls the first switch to be turned on and the second switch to be turned off.

[0044] In a possible implementation, the inductor further comprises a first inductor and a second inductor; in the seventh state, the battery pack further controls the second inductor to be connected with the first battery in series through the switch group, so as to charge the first battery through the second inductor.

[0045] In the eighth state, the battery pack further controls the second inductor to be connected with the second battery in series through the switch group, so as to charge the second inductor through the second battery.

[0046] In a possible implementation, the switch group comprises a first switch, a second switch, a third switch and a fourth switch; a first end of the first switch is connected with a positive electrode of the first battery and a first end of the second switch respectively;

[0047] a first end of the first inductor is connected with a negative electrode of the first battery and a positive electrode of the second battery respectively, and a second end of the first inductor is connected with a second end of the first switch and a first end of the third switch respectively;

[0048] a first end of the second inductor is connected with a negative electrode of the first battery and a positive electrode of the second battery respectively, and a second end of the second inductor is connected with a second end of the second switch and a first end of the fourth switch respectively;

[0049] a second end of the third switch is connected with a negative electrode of the second battery and a second end of the fourth switch respectively;

[0050] In the seventh state, the battery pack controls the third switch and the fourth switch to be turned on, and controls the first switch and the second switch to be turned off.

[0051] In the eighth state, the battery pack controls the first switch and the fourth switch to be turned on, and controls the second switch and the third switch to be turned off.

[0052] In a possible implementation, the battery pack further comprises a fifth switch, a sixth switch, a seventh switch and an eighth switch, a first end of the fifth switch is electrically connected with a positive pole of the first battery and a first end of the seventh switch respectively; a second end of the fifth switch is electrically connected with a first end of the first switch, a first end of the second switch and a first interface of the electric energy interface respectively;

[0053] a first end of the sixth switch is electrically connected with a negative pole of the second battery and a first end of the eighth switch, and a second end of the sixth switch is electrically connected with a second end of the fifth switch, a second end of the sixth switch and a second interface of the electric energy interface respectively;

[0054] a second end of the seventh switch is electrically connected with a second end of the first switch and a first end of the fifth switch respectively; and a second end of the eighth switch is electrically connected with a second end of the second switch and a first end of the sixth switch respectively.

[0055] In a possible implementation, the switch group has a first state and a second state, and the switch group is configured to reciprocally switch the first state and the second state, so as to make the electric energy interface output alternating current;

[0056] The switch group further has a third state and a fourth state, and the switch group is further configured to reciprocally switch the third state and the fourth state, so as to control the battery to step up power transmission to the electric energy interface;

[0057] The battery pack controls the fifth switch and the sixth switch to be disconnected, and the seventh switch and the eighth switch to be connected, so that the switch group can be used to reciprocally switch the first state and the second state;

[0058] The battery pack controls the fifth switch and the sixth switch to be connected, and the seventh switch and the eighth switch to be disconnected, so that the switch group is used to reciprocally switch the third state and the fourth state.

[0059] In a second aspect, the application further provides a control method of a battery pack, the control method of the battery pack being applied to a battery pack, the battery pack comprising a battery, a switch group and an electric energy interface, the switch group being electrically connected with the battery and the electric energy interface respectively; the switch group being configured to control the battery to deliver direct current to the electric energy interface; the switch group being configured to reciprocally switch states under the control of the battery pack, so as to change a current direction of the battery flowing to the electric energy interface, so as to output alternating current for the electric energy interface, the control method of the battery pack comprising the following steps:

[0060] controlling the battery to deliver direct current to the electric energy interface;

[0061] The state of the switch group is reciprocally switched to change the current direction of the battery to the power interface, so as to output alternating current for the power interface.

[0062] In a possible implementation, the reciprocally switching the state of the switch group to change the current direction of the battery to the power interface comprises the following steps:

[0063] controlling the positive electrode of the battery to be connected to the first interface and the negative electrode of the battery to be connected to the second interface, so as to make the switch group enter a first state;

[0064] controlling the negative electrode of the battery to be connected to the first interface and the negative electrode of the battery to be connected to the second interface, so as to make the switch group enter a second state;

[0065] controlling the switch group to reciprocally switch between the first state and the second state.

[0066] In a possible implementation, the switch group comprises a first switch, a second switch, a third switch and a fourth switch; the first end of the first switch is connected to the positive electrode of the battery, the first end of the second switch and the first interface respectively; the second end of the first switch is connected to the first end of the third switch; the second end of the second switch is connected to the first end of the fourth switch; the second end of the third switch is connected to the negative electrode of the battery, the second end of the fourth switch and the second interface respectively;

[0067] The controlling the positive electrode of the battery to be connected to the first interface and the negative electrode of the battery to be connected to the second interface comprises the following steps:

[0068] controlling the first switch and the fourth switch to be closed; and controlling the second switch and the third switch to be opened;

[0069] The controlling the negative electrode of the battery to be connected to the first interface and the negative electrode of the battery to be connected to the second interface comprises the following steps:

[0070] controlling the second switch and the third switch to be closed; and controlling the first switch and the fourth switch to be opened.

[0071] In a possible implementation, the battery pack further comprises an inductor, which is electrically connected to the battery and the switch group respectively; and the control method of the battery pack further comprises:

[0072] controlling the battery and the inductor to be connected in series, so as to make the switch group enter a third state;

[0073] controlling the battery, the inductor and the power interface to be connected in series, so as to make the switch group enter a fourth state.

[0074] controlling the switch group to reciprocate between the third state and the fourth state.

[0075] In a possible implementation, the electric energy interface includes a first interface and a second interface, and the switch group includes a first switch and a second switch; a first end of the first switch is connected with a positive pole of the battery and the first interface respectively; a first end of the inductor is connected with a negative pole of the battery, and a second end of the inductor is connected with a first end of the second switch; a second end of the second switch is connected with the second interface;

[0076] the control of the battery and the inductor in series to make the switch group enter the third state includes the following steps:

[0077] controlling the first switch to be closed and the second switch to be opened;

[0078] the control of the battery and the inductor in series with the electric energy interface to make the switch group enter the fourth state includes the following steps:

[0079] controlling the first switch and the second switch to be closed.

[0080] In a possible implementation, the battery pack further includes an inductor, the battery includes a first battery and a second battery which are electrically connected with each other, and a negative pole of the first battery is electrically connected with a positive pole of the second battery; a first end of the inductor is connected with the negative pole of the first battery and the positive pole of the second battery respectively, and a second end of the inductor is connected with the switch group;

[0081] when a difference between the charge amount of the first battery and the charge amount of the second battery is greater than a preset threshold, the control method of the battery pack further includes:

[0082] controlling the first battery and the inductor in series through the switch group to make the switch group enter a fifth state;

[0083] controlling the inductor and the second battery in series through the switch group to make the switch group enter a sixth state;

[0084] controlling the switch group to reciprocate between the fifth state and the sixth state.

[0085] In a possible implementation, the switch group comprises a first switch and a second switch; a first end of the first switch is connected with a positive pole of the first battery; first ends of the inductor are connected with a negative pole of the first battery and a positive pole of the second battery respectively; a second end of the inductor is connected with a second end of the first switch and a first end of the second switch respectively; a second end of the second switch is connected with a negative pole of the second battery;

[0086] The control of the first battery and the inductor in series through the switch group to make the switch group enter the fifth state comprises the steps of:

[0087] controlling the first switch to be closed and the second switch to be opened;

[0088] The control of the inductor and the second battery in series through the switch group to make the switch group enter the sixth state comprises the steps of:

[0089] controlling the first switch to be opened and the second switch to be closed.

[0090] In a possible implementation, the battery pack further comprises an inductor, the battery comprises a first battery and a second battery which are electrically connected with each other, a negative pole of the first battery is electrically connected with a positive pole of the second battery; a first end of the inductor is connected with the negative pole of the first battery and the positive pole of the second battery respectively, and a second end of the inductor is connected with the switch group;

[0091] When a difference between the charge amount of the second battery and the charge amount of the first battery is greater than a preset threshold, the control method of the battery pack further comprises:

[0092] controlling the second battery and the inductor in series through the switch group to make the switch group enter a seventh state;

[0093] controlling the first battery and the inductor in series through the switch group to make the switch group enter an eighth state;

[0094] controlling the switch group to switch back and forth between the seventh state and the eighth state.

[0095] In a possible implementation, the switch group comprises a first switch and a second switch; a first end of the first switch is connected with a positive pole of the first battery; first ends of the inductor are connected with a negative pole of the first battery and a positive pole of the second battery respectively; a second end of the inductor is connected with a second end of the first switch and a first end of the second switch respectively; a second end of the second switch is connected with a negative pole of the second battery;

[0096] controlling the first switch to be closed and the second switch to be opened.

[0097] controlling the first switch to be closed and the second switch to be opened.

[0098] controlling the first switch to be closed and the second switch to be opened.

[0099] controlling the first switch to be closed and the second switch to be opened.

[0100] In a third aspect, the present application provides an electric energy device, comprising a battery pack, the battery pack comprising a battery, a switch group and an electric energy interface, the switch group being electrically connected with the battery and the electric energy interface respectively;

[0101] the switch group is configured to control the battery to deliver direct current to the electric energy interface;

[0102] the switch group is configured to reciprocally switch states under the control of the battery pack to change the current direction of the battery flowing to the electric energy interface, so as to output alternating current for the electric energy interface.

[0103] In a fourth aspect, the present application provides an energy storage system, comprising:

[0104] a current network; and

[0105] at least one battery pack, the battery pack being electrically connected with the current network, the battery pack comprising a battery, a switch group and an electric energy interface, the switch group being electrically connected with the battery and the electric energy interface respectively;

[0106] the switch group is configured to control the battery to deliver direct current to the electric energy interface;

[0107] the switch group is configured to reciprocally switch states under the control of the battery pack to change the current direction of the battery flowing to the electric energy interface, so as to output alternating current for the electric energy interface.

[0108] The technical scheme of the present application increases the use of the original switch group, so that the switch group can perform AC / DC conversion while completing direct current power supply. In this way, the problem of connecting the battery pack and the energy storage power station in parallel is solved without increasing additional electrical elements and without equipping additional inverters, and the cost of connecting the battery pack and the energy storage power station in parallel is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0109] FIG. 1 is a structural schematic diagram of an embodiment of the energy storage system provided by the present application;

[0110] Fig. 2 is a schematic diagram of the circuit structure of the battery pack in Fig. 1;

[0111] Fig. 3 is a current flow diagram of the switch group in Fig. 2 in a first state;

[0112] Fig. 4 is a current flow diagram of the switch group in Fig. 2 in a second state;

[0113] Fig. 5 is a schematic diagram of the circuit structure of an embodiment of the switch group in Fig. 2 in a third state;

[0114] Fig. 6 is a schematic diagram of the circuit structure of another embodiment of the switch group in Fig. 2 in a fourth state;

[0115] Fig. 7 is a current flow diagram of an embodiment of the switch group in Fig. 2 in a fifth state;

[0116] Fig. 8 is a current flow diagram of an embodiment of the switch group in Fig. 2 in a sixth state;

[0117] Fig. 9 is a current flow diagram of another embodiment of the switch group in Fig. 2 in a fifth state;

[0118] Fig. 10 is a current flow diagram of another embodiment of the switch group in Fig. 2 in a sixth state;

[0119] Fig. 11 is a current flow diagram of an embodiment of the switch group in Fig. 2 in a seventh state;

[0120] Fig. 12 is a current flow diagram of an embodiment of the switch group in Fig. 2 in an eighth state;

[0121] Fig. 13 is a current flow diagram of another embodiment of the switch group in Fig. 2 in a seventh state;

[0122] Fig. 14 is a current flow diagram of another embodiment of the switch group in Fig. 2 in an eighth state;

[0123] Fig. 15 is an equivalent circuit diagram of the battery pack in Fig. 1 outputting direct current;

[0124] Fig. 16 is an equivalent circuit diagram of the battery pack in Fig. 1 outputting alternating current;

[0125] Fig. 17 is a schematic diagram of the hardware operating environment of the battery pack in Fig. 1;

[0126] Fig. 18 is a schematic diagram of the first embodiment of the control method of the battery pack provided in the present application;

[0127] Fig. 19 is a schematic diagram of an embodiment of the battery pack changing the current direction of the battery to the power interface by reciprocating the switch group;

[0128] Fig. 20 is a schematic diagram of the second embodiment of the control method of the battery pack provided in the present application;

[0129] FIG. 21 is a flow diagram of a third embodiment of a control method of a battery pack according to the present application;

[0130] FIG. 22 is a flow diagram of a fourth embodiment of a control method of a battery pack according to the present application.

[0131] BRIEF DESCRIPTION OF DRAWINGS 1000 - energy storage system, 200 - current network, 300 - controller; 100 - battery pack; 1 - battery, 11 - first battery, 12 - second battery; 2 - switch group, 21 - first switch, 22 - second switch, 23 - third switch, 24 - fourth switch; 3 - transformer, 31 - first transformation part, 32 - second transformation part; 4 - power interface, 41 - first interface, 42 - second interface; L - inductor, L1 first inductor, L2 - second inductor; K5 - fifth switch, K6 - sixth switch, K7 - seventh switch, K8 - eighth switch, K9 - ninth switch, K10 - tenth switch, K11 - eleventh switch, K12 - twelfth switch, K13 - thirteenth switch, K14 - fourteenth switch, K15 - fifteenth switch, K16 - sixteenth switch, K17 - seventeenth switch; R1 - first resistor, R2 second resistor, C - capacitor; 1001 - communication bus, 1002 - user interface, 1003 - network interface, 1004 - memory. DETAILED DESCRIPTION

[0132] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangements, numerical expressions, and numerical values of components and steps set forth in these embodiments are not limiting to the scope of the present application unless otherwise specifically stated.

[0133] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting to the scope of the application or its applications or uses.

[0134] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein, but should be considered as part of the specification, where appropriate.

[0135] In all examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as a limitation. Thus, other examples of the exemplary embodiments can have different values.

[0136] It should be noted that like numbers and letters refer to like elements throughout the several views of the drawings and that, unless otherwise specified, the use of the same or similar reference numbers and letters in different figures indicates the same or similar elements.

[0137] The application provides a battery pack which can be applied to an electric energy device. The electric energy device can be a vehicle, an aircraft or a ship, and the application does not make any limitation in this regard.

[0138] Exemplarily, taking a vehicle as an example, when the battery pack is applied to the vehicle, the vehicle can be an electric vehicle, a fuel vehicle or a hybrid vehicle according to the power source, and the application does not make any limitation in this regard. According to the vehicle category, the vehicle can be a car, a truck or a forklift, and the application does not make any limitation in this regard.

[0139] The vehicle comprises a vehicle body, an electric device and the battery pack. The vehicle body serves as a support framework of the vehicle and is used for supporting and connecting various part assemblies of the vehicle. The electric device is arranged on the vehicle body, and the electric device can be a motor, an instrument panel or a window lifting mechanism, and the application does not make any limitation in this regard.

[0140] The battery pack is accommodated in the vehicle body and is electrically connected with the electric device. The battery pack is used for storing and providing electric quantity to the electric device when the electric device needs, so as to maintain the normal use of the electric device.

[0141] During the vehicle use, the performance of the battery pack will gradually decline. Generally, when the capacity of the battery pack is attenuated to less than 80% of the initial capacity, the battery pack can no longer meet the use requirements of high endurance and high power of the vehicle. At this time, the maintenance personnel of the vehicle will replace the new battery pack for the vehicle, and the old battery pack will be retired.

[0142] Although the retired battery pack cannot be adapted to the high energy demand occasions such as vehicles, the remaining capacity of the retired battery pack can still meet the requirements of low energy demand scenes such as energy storage and standby power supply. Therefore, the retired battery pack is usually sent into an energy storage system.

[0143] Please refer to FIG. 1, when the battery pack 100 is applied to the energy storage system 1000, the energy storage system 1000 can be an energy storage power station or a household energy storage device, and the present application does not limit this. Taking the energy storage power station as an example, the energy storage power station includes a current network 200 and a battery pack 100. One end of the current network 200 is connected to a power generation device, and the other end is connected to each power consumption load. The battery pack 100 is connected to the current network 200, and when the power generation capacity of the power generation device is greater than the power consumption capacity of each power consumption load, the battery pack 100 is used to store power. When the power generation capacity of the power generation device is less than the power consumption capacity of each power consumption load, the battery pack 100 stores power. It should be understood that in other embodiments of the present application, the energy storage power station can also include a controller 300, the controller 300 is electrically connected to the battery pack 100, and the controller 300 can control the charging and discharging of the battery pack 100, so that the battery pack 100 stores power when there is surplus power generation capacity of the power generation device, and releases power when the power generation capacity of the power generation device is insufficient.

[0144] In related technologies, the battery pack is usually connected to the energy storage power station through an inverter, and the inverter is used to convert the direct current of the battery pack into alternating current available for the current network, or to convert the alternating current of the current network into direct current available for the battery pack, so as to realize the grid connection of the battery pack and the current network. However, due to the difference in voltage platforms of battery packs produced by different manufacturers and vehicle models, different inverters need to be equipped to adapt the current of the battery pack and the energy storage power station when different battery packs are connected to the energy storage power station in parallel. The cost of parallel connection of the battery pack and the energy storage power station increases.

[0145] Please refer to FIG. 2, to solve the above problems, in the present application, the battery pack 100 includes a battery 1, a switch group 2 and an electrical energy interface 4, the switch group 2 is electrically connected to the battery 1 and the electrical energy interface 4 respectively; the switch group 2 is used to control the battery 1 to deliver direct current to the electrical energy interface 4; the switch group 2 is used to reciprocally switch states under the control of the battery pack 100, so as to change the current direction of the battery 1 flowing to the electrical energy interface 4, so as to output alternating current for the electrical energy interface 4.

[0146] The technical scheme of the present application increases the use of the original switch group 2, so that the switch group can not only complete direct current power supply, but also can perform AC / DC conversion. In this way, the problem of parallel connection of the battery pack 100 and the energy storage power station is solved without increasing additional electrical elements and without equipping additional inverters, and the cost of parallel connection of the battery pack 100 and the energy storage power station is reduced.

[0147] In the following, the battery pack 100 provided by the present application will be described in detail in combination with the drawings.

[0148] The battery pack 100 includes a battery 1, which is used as an energy storage unit of the battery pack 100, for storing and releasing electrical energy for use by electrical devices or power consumption loads.

[0149] The battery pack 100 further comprises an electric energy interface 4, which is used to connect with the electric device when the battery pack 100 is applied to the electric device, and is used to connect with the current network when the battery pack 100 is applied to the energy storage power station. The electric energy interface 4 comprises a first interface 41 and a second interface 42, one end of the first interface 41 is connected with the positive electrode of the battery 1, and the other end is connected with the positive electrode of the electric device or the positive electrode of the current network; one end of the second interface 42 is connected with the negative electrode of the battery 1, and the other end is connected with the negative electrode of the electric device or the negative electrode of the current network.

[0150] The battery pack 100 further comprises a switch group 2, which comprises a plurality of switches, and the switch group 2 can control the current flowing direction of the circuit by controlling the on-off of each switch. In the related art, the switch group 2 is used to control the circuit of the battery pack 100, so that the battery 1 can deliver direct current to the electric energy interface 4. In the present application, the switch group can not only be used to control the battery 1 to deliver direct current to the electric energy interface 4, but also be used to reciprocally switch the state under the control of the battery pack 100, so as to change the current direction of the battery 1 flowing to the electric energy interface 4, and output alternating current for the electric energy interface 4.

[0151] The technical scheme of the present application increases the use of the original switch group 2, so that the switch group can not only complete direct current power supply, but also can perform AC-DC conversion. In this way, the problem of connecting the battery pack 100 and the energy storage power station in grid connection is solved without increasing additional electrical elements and without equipping additional inverters, and the cost of connecting the battery pack 100 and the energy storage power station in grid connection is reduced.

[0152] Specifically, referring to FIGS. 3 and 4, the switch group 2 has a first state and a second state, in the first state, the battery pack 100 controls the positive electrode of the battery 1 to be connected with the first interface 41, and the negative electrode of the battery 1 to be connected with the second interface 42; in the second state, the battery pack 100 controls the negative electrode of the battery 1 to be connected with the first interface 41, and the negative electrode of the battery 1 to be connected with the second interface 42. The switch group 2 can reciprocally switch the first state and the second state, so that the positive electrode of the battery 1 and the negative electrode of the battery 1 are alternately connected with the first interface 41 and the second interface 42, so that the battery 1 can output alternating current to the electric energy interface 4.

[0153] In a specific implementation, the switch group 2 includes a first switch 21, a second switch 22, a third switch 23, and a fourth switch 24; the first end of the first switch 21 is connected with the positive pole of the battery 1 respectively, the first end of the second switch 22, and the first interface 41; the second end of the first switch 21 is connected with the first end of the third switch 23; the second end of the second switch 22 is connected with the first end of the fourth switch 24; the second end of the third switch 23 is connected with the negative pole of the battery 1, the second end of the fourth switch 24, and the second interface 42 respectively.

[0154] Please refer to FIG. 3, in the first state, the battery pack 100 controls the first switch 21 and the fourth switch 24 to be closed; controls the second switch 22 and the third switch 23 to be opened, and the current of the battery 1 reaches the negative pole of the battery 1 via the positive pole of the battery 1, the first switch 21, the first interface 41, the second interface 42, and the fourth switch 24.

[0155] Please refer to FIG. 4, in the second state, the battery pack 100 controls the second switch 22 and the third switch 23 to be closed, and controls the first switch 21 and the fourth switch 24 to be opened, and the current of the battery 1 reaches the negative pole of the battery 1 via the positive pole of the battery 1, the third switch 23, the second interface 42, the first interface 41, and the second switch 22.

[0156] The switch group 2 repeatedly switches between the first state and the second state, so as to convert the direct current of the battery 1 into the alternating current required by the current network. Similarly, when the alternating current of the current network is delivered to the battery 1 from the first interface 41 and the second interface 42, the switch group 2 can also convert the alternating current of the current network into direct current by switching between the first state and the second state.

[0157] Please refer to FIG. 5 and FIG. 6, when the battery pack 100 is applied to an electrical equipment, the battery pack 100 can also control the switch group 2 to supply power to the battery 1 in a boosted mode. Specifically, the battery pack 100 further includes an inductor L, which is electrically connected with the battery 1 and the switch group 2 respectively; the switch group 2 further has a third state and a fourth state, in the third state, the battery 1 is connected in series with the inductor L to charge the inductor L; in the fourth state, the battery 1 and the inductor L are connected in series with the power interface 4 to jointly deliver power to the power interface 4.

[0158] When the electrical equipment connected with the battery pack 100 needs a larger voltage, the battery pack 100 can control the switch group 2 to repeatedly switch between the third state and the fourth state, so as to realize the boosted charging for the electrical equipment. Meanwhile, in some scenarios, in order to improve the voltage and charge capacity of the battery 1, the battery 1 is often composed of multiple batteries 1 connected in series. For the convenience of description, it is assumed that the battery pack 100 includes a first battery 11 and a second battery 11. When the battery pack 100 is working normally, the first battery 11 and the second battery 11 are connected in series with each other, and jointly deliver power to the power interface 4.

[0159] As shown in FIG. 5, when the charge of the first battery 11 is less than the safe charge, the switch group 2 can disconnect the first battery 11 and constantly switch the third state and the fourth state to connect the first battery 11 and the inductor L in series and then connect the first battery 11, the inductor L and the power interface 4 in series, so that the inductor L replaces the first battery 11 to supply power to the power interface 4. Thus, the first battery 11 is prevented from being damaged due to over-discharge.

[0160] As shown in FIG. 6, when the charge of the first battery 11 is less than the safe charge, the switch group 2 can disconnect the first battery 11 and constantly switch the fourth state and the fifth state to connect the first battery 11 and the inductor L in series and then connect the first battery 11, the inductor L and the power interface 4 in series, so that the inductor L replaces the first battery 11 to supply power to the power interface 4. Thus, the first battery 11 is prevented from being damaged due to over-discharge.

[0161] In a specific implementation, the switch group 2 includes a first switch 21 and a second switch 22; the first end of the first switch 21 is connected to the positive pole of the battery 1 and the first interface 41 respectively; the first end of the inductor L is connected to the negative pole of the battery 1, and the second end of the inductor L is connected to the first end of the second switch 22; the second end of the second switch 22 is connected to the second interface 42.

[0162] In the third state, the battery pack 100 controls the first switch 21 to be closed and the second switch 22 to be disconnected. In the fourth state, the battery pack 100 controls the first switch 21 and the second switch 22 to be closed. The switch group 2 constantly switches the closing order of the first switch 21 and the second switch 22, so as to realize the boost charging of the battery 1.

[0163] It can be understood that in some application scenarios, in order to improve the voltage and charge capacity of the battery 1, the battery 1 is often composed of multiple batteries 1 connected in series. Here, it is still assumed that the battery pack 100 includes the first battery 11 and the first battery 11. When the battery pack 100 works normally, the first battery 11 and the first battery 11 are connected in series with each other and jointly supply power to the power interface 4.

[0164] However, due to the differences in internal parameters, different aging degrees, changes in environmental temperature and other reasons, the first battery 11 and the first battery 11 cannot uniformly supply power to the power interface 4, but a charge difference will be generated. If the charge difference between the first battery 11 and the first battery 11 exceeds a preset threshold, the overall performance of the battery pack 100 will be reduced, and in severe cases, safety problems may even be caused.

[0165] Please refer to FIG. 7 and FIG. 8, in order to avoid the above problems, in the present application, the switch group 2 can also stabilize the circuit of the battery pack 100. Specifically, the battery pack 100 further comprises an inductor L, the battery pack 100 comprises the first battery 11 and the first battery 11 which are electrically connected to each other, the negative electrode of the first battery 11 is electrically connected to the positive electrode of the first battery 11; the first end of the inductor L is connected to the negative electrode of the first battery 11 and the positive electrode of the first battery 11 respectively, and the second end of the inductor L is connected to the switch group 2. The switch group 2 further has a fifth state and a sixth state, in the fifth state, the battery pack 100 controls the first battery 11 and the inductor L to be connected in series through the switch group 2. In the sixth state, the battery pack 100 controls the first inductor L1 and the first battery 11 to be connected in series through the switch group 2, so as to charge the first battery 11 through the first inductor L1. The switch group 2 can reciprocatingly switch the fifth state and the sixth state, so as to keep the first battery 11 and the first battery 11 balanced.

[0166] In a specific implementation, the switch group 2 comprises a first switch 21 and a second switch 22; the first end of the first switch 21 is connected to the positive electrode of the first battery 11; the first end of the inductor L is connected to the negative electrode of the first battery 11 and the positive electrode of the first battery 11 respectively; the second end of the inductor L is connected to the second end of the first switch 21 and the first end of the second switch 22 respectively; the second end of the second switch 22 is connected to the negative electrode of the first battery 11;

[0167] As shown in FIG. 7, in the fifth state, the battery pack 100 controls the first switch 21 to be closed and the second switch 22 to be opened, and the current of the battery pack 100 flows from the positive electrode of the first battery 11, the first switch 21, the inductor L to the negative electrode of the first battery 11, so as to charge the inductor L by the first battery 11.

[0168] As shown in FIG. 8, in the sixth state, the battery pack 100 controls the first switch 21 to be opened and the second switch 22 to be closed, and the current of the battery pack 100 flows from the second end of the inductor L, the second switch 22, the negative electrode of the first battery 11, the positive electrode of the first battery 11 to the first end of the inductor L, so as to charge the first battery 11 by the inductor L. The battery pack 100 continuously switches the switch state of the first switch 21 and the second switch 22, so as to balance the charge amount of the first battery 11 and the first battery 11, and ensure the safety of the battery pack 100.

[0169] Please refer to FIG. 9, in order to improve the stability of the inductance L charging the first battery 11, in an embodiment of the present application, the inductance L further comprises a first inductance L1 and a second inductance L2; in the fifth state, the battery pack 100 further controls the second inductance L2 to be in series with the first battery 11 through the switch group 2, so as to charge the first battery 11 through the second inductance L2; in the sixth state, the battery pack 100 further controls the second inductance L2 to be in series with the first battery 11 through the switch group 2, so as to charge the second inductance L2 through the first battery 11. In the embodiment, the first battery 11 will be in series with the first inductance L1 and the second inductance L2 in turn, and similarly, the first inductance L1 and the second inductance L2 will also be in series with the first battery 11 in turn.

[0170] Specifically, when the switch group 2 is switched to the fifth state for the first time, at this time, the first battery 11 is in series with the first inductance L1, and the second inductance L2 is in series with the first battery 11, at this time, the first battery 11 charges the first inductance L1, and the first battery 11 charges the second inductance L2. When the switch group 2 is switched to the sixth state, the first inductance L1 is in series with the first battery 11 and charges the first battery 11. The first battery 11 is in series with the second inductance L2, and because the charge amount of the first battery 11 is less than that of the first battery 11, at this time, the charge amount of the second inductance L2 is also less than that of the first battery 11, and the first battery 11 charges the second inductance L2.

[0171] When the switch group 2 is switched to the fifth state again (at this time, the current starts to stabilize), the first battery 11 is in series with the first inductance L1 and charges the first inductance L1, and the second inductance L2 is in series with the first battery 11 and charges the first battery 11. When the switch group 2 is switched to the sixth state again, the first inductance L1 is in series with the first battery 11 and charges the first battery 11. The first battery 11 is in series with the second inductance L2 and charges the second inductance L2, and the cycle is repeated until the charge amounts of the first battery 11 and the first battery 11 are equal. In this way, the cyclic charging of the first battery 11 is realized, the stability of the charging of the first battery 11 is ensured, and the stability of the circuit operation of the battery pack 100 is improved.

[0172] In a specific implementation, the switch group 2 includes a first switch 21, a second switch 22, a third switch 23, and a fourth switch 24; the first end of the first switch 21 is connected with the positive pole of the first battery 11 and the first end of the second switch 22 respectively; the first end of the first inductor L1 is connected with the negative pole of the first battery 11 and the positive pole of the first battery 11 respectively, and the second end of the first inductor L1 is connected with the second end of the first switch 21 and the first end of the third switch 23 respectively; the first end of the second inductor L2 is connected with the negative pole of the first battery 11 and the positive pole of the first battery 11 respectively, and the second end of the second inductor L2 is connected with the second end of the second switch 22 and the first end of the fourth switch 24 respectively; the second end of the third switch 23 is connected with the negative pole of the first battery 11 and the second end of the fourth switch 24 respectively.

[0173] As shown in FIG. 9, in the fifth state, the battery pack 100 controls the first switch 21 and the fourth switch 24 to be closed, and controls the second switch 22 and the third switch 23 to be opened. A part of the current of the battery pack 100 passes through the positive pole of the first battery 11, the first switch 21, the first inductor L1, and reaches the negative pole of the first battery 11, thereby charging the first inductor L1. Another part of the current of the battery pack 100 passes through the second end of the second inductor L2, the fourth switch 24, the negative pole of the first battery 11, the positive pole of the first battery 11, and flows to the first end of the second inductor L2, thereby charging the first battery 11.

[0174] As shown in FIG. 10, in the sixth state, the battery pack 100 controls the second switch 22 and the third switch 23 to be closed, and controls the first switch 21 and the fourth switch 24 to be opened. A part of the current of the battery pack 100 passes through the positive pole of the first battery 11, the second switch 22, the second inductor L2, and reaches the negative pole of the first battery 11, thereby charging the second inductor L2. Another part of the current of the battery pack 100 passes through the second end of the first inductor L1, the third switch 23, the negative pole of the first battery 11, the positive pole of the first battery 11, and flows to the first end of the first inductor L1, thereby charging the first battery 11.

[0175] Similarly, please refer to FIG. 11 and FIG. 12, when the charge amount of the first battery 11 is less than the preset charge amount, the first battery 11 can also be charged by the inductor L, specifically, the switch group 2 has a seventh state and an eighth state, and the switch group 2 also reciprocatingly switches the seventh state and the eighth state, so that the first battery 11 and the first battery 11 are balanced. In the seventh state, the battery pack 100 controls the first battery 11 and the first inductor L1 to be in series through the switch group 2, so as to charge the first inductor L1 through the first battery 11. In the eighth state, the battery pack 100 controls the first battery 11 and the first inductor L1 to be in series through the switch group 2, so as to charge the first battery 11 through the first inductor L1.

[0176] In a specific implementation, the switch group 2 includes a first switch 21 and a second switch 22; a first end of the first switch 21 is connected to the positive pole of the first battery 11; a first end of the inductor L is connected to the negative pole of the first battery 11 and the positive pole of the first battery 11 respectively; a second end of the inductor L is connected to a second end of the first switch 21 and a first end of the second switch 22 respectively; a second end of the second switch 22 is connected to the negative pole of the first battery 11.

[0177] As shown in FIG. 11, in the seventh state, the battery pack 100 controls the first switch 21 to be open and the second switch 22 to be closed. The current of the battery pack 100 flows from the positive pole of the first battery 11, the inductor L, the second switch 22 to the negative pole of the first battery 11, so as to charge the inductor L by the first battery 11.

[0178] As shown in FIG. 12, in the eighth state, the battery pack 100 controls the first switch 21 to be closed and the second switch 22 to be open. The current of the battery pack 100 flows from the first end of the inductor L, the negative pole of the first battery 11, the positive pole of the first battery 11, the first switch 21 to the second end of the inductor L, so as to charge the inductor L by the first battery 11.

[0179] Please refer to FIG. 13 and FIG. 14, in order to improve the stability of the inductor L charging the first battery 11, in an implementation of the present application, the inductor L further includes a first inductor L1 and a second inductor L2; in the seventh state, the battery pack 100 further controls the second inductor L2 to be connected in series with the first battery 11 through the switch group 2, so as to charge the first battery 11 by the second inductor L2; in the eighth state, the battery pack 100 further controls the second inductor L2 to be connected in series with the first battery 11 through the switch group 2, so as to charge the second inductor L2 by the first battery 11.

[0180] Specifically, when the switch group 2 is switched to the seventh state for the first time, at this time, the first battery 11 is connected in series with the first inductor L1, and the first battery 11 is connected in series with the second inductor L2. The first battery 11 charges the first inductor L1, and the first battery 11 charges the second inductor L2. When the switch group 2 is switched to the eighth state, the first inductor L1 is connected in series with the first battery 11 and charges the first battery 11. The first battery 11 is connected in series with the second inductor L2, and since the charge amount of the first battery 11 is less than the charge amount of the first battery 11, at this time, the charge amount of the second inductor L2 is also less than the charge amount of the first battery 11, and the first battery 11 charges the second inductor L2.

[0181] When the switch group 2 is switched to the seventh state again (at this time the current begins to stabilize), the first battery 11 is in series with the first inductor L1 and charges the first inductor L1, and the second inductor L2 is in series with the first battery 11 and charges the first battery 11. When the switch group 2 is switched to the eighth state again, the first inductor L1 is in series with the first battery 11 and charges the first battery 11. The first battery 11 is in series with the second inductor L2 and charges the second inductor L2, and the cycle is repeated until the charge amount of the first battery 11 and the first battery 11 is equal. In this way, the cyclic charging of the first battery 11 is realized, the stability of the charging of the first battery 11 is ensured, and the stability of the circuit operation of the battery pack 100 is improved.

[0182] In a specific implementation, the switch group 2 includes a first switch 21, a second switch 22, a third switch 23, and a fourth switch 24; the first end of the first switch 21 is connected with the positive electrode of the first battery 11 and the first end of the second switch 22 respectively; the first end of the first inductor L1 is connected with the negative electrode of the first battery 11 and the positive electrode of the first battery 11 respectively, and the second end of the first inductor L1 is connected with the second end of the first switch 21 and the first end of the third switch 23 respectively; the first end of the second inductor L2 is connected with the negative electrode of the first battery 11 and the positive electrode of the first battery 11 respectively, and the second end of the second inductor L2 is connected with the second end of the second switch 22 and the first end of the fourth switch 24 respectively; the second end of the third switch 23 is connected with the negative electrode of the first battery 11 and the second end of the fourth switch 24 respectively;

[0183] As shown in FIG. 13, in the seventh state, the battery pack 100 controls the third switch 23 and the fourth switch 24 to be closed, and controls the first switch 21 and the second switch 22 to be opened. Part of the current of the battery pack 100 flows to the negative electrode of the first battery 11 via the positive electrode of the first battery 11, the first inductor L1, and the third switch 23, thereby charging the first inductor L1. Part of the current of the battery pack 100 reaches the second end of the second inductor L2 via the first end of the second inductor L2, the negative electrode of the first battery 11, the positive electrode of the first battery 11, and the second switch 22, thereby realizing the charging of the first battery 11.

[0184] In the eighth state, the battery pack 100 controls the first switch 21 and the fourth switch 24 to be closed, and controls the second switch 22 and the third switch 23 to be opened. Part of the current of the battery pack 100 reaches the negative electrode of the first battery 11 via the positive electrode of the first battery 11, the second inductor L2, and the fourth switch 24, thereby charging the second inductor L2. Part of the current of the battery pack 100 reaches the second end of the first inductor L1 via the first end of the first inductor L1, the negative electrode of the first battery 11, the positive electrode of the first battery 11, and the first switch 21, thereby charging the first battery 11.

[0185] Referring to FIG. 2, in order to realize the switching of the battery pack 100 between states, the battery pack 100 further comprises a fifth switch K5, a sixth switch K6, a seventh switch K7, and an eighth switch K8. The first end of the fifth switch K5 is electrically connected with the positive pole of the first battery 11 and the first end of the seventh switch K7 respectively. The second end of the fifth switch K5 is electrically connected with the first end of the first switch 21, the first end of the second switch 22, and the first interface 41 of the electric energy interface 4 respectively. The first end of the sixth switch K6 is electrically connected with the negative pole of the first battery 11 and the first end of the eighth switch K8. The second end of the sixth switch K6 is electrically connected with the second end of the fifth switch K5, the second end of the sixth switch K6, and the second interface 42 of the electric energy interface 4 respectively. The second end of the seventh switch K7 is electrically connected with the second end of the first switch 21 and the first end of the fifth switch K5 respectively. The second end of the eighth switch K8 is electrically connected with the second end of the second switch 22 and the first end of the sixth switch K6 respectively.

[0186] Correspondingly, the battery pack 100 further comprises a ninth switch K9 and a tenth switch K10. The first end of the ninth switch K9 is connected with the negative pole of the first battery 11 and the positive pole of the second battery 12 respectively. The second end of the ninth switch K9 is connected with the first inductor L1. The first end of the tenth switch K10 is connected with the negative pole of the first battery 11 and the positive pole of the second battery 12 respectively. The second end of the tenth switch K10 is connected with the second inductor L2.

[0187] When the seventh switch K7 and the eighth switch K8 are closed and the switch group 2 is closed, the battery pack 100 outputs direct current to the outside. When the seventh switch K7, the eighth switch K8, the ninth switch K9, and the tenth switch K10 are closed, the equivalent circuit diagram of the battery pack 100 is shown in FIG. 15. At this time, the battery pack 100 can control the switch group 2 to switch between the third state and the eighth state, or the battery pack 100 can close the switch group 2 and directly output direct current to the outside.

[0188] When the fifth switch K5 and the sixth switch K6 are closed, the equivalent circuit diagram of the battery pack 100 is shown in FIG. 16. At this time, the battery pack 100 can control the switch group 2 to switch between the first state and the second state to output alternating current to the outside, or convert the external alternating current into direct current to charge the battery 1.

[0189] In order to keep the voltage outputted from the battery pack 100 or the voltage inputted into the battery pack 100 by the energy storage system 1000 within the suitable range of the battery pack 100 and the energy storage system 1000, in an embodiment of the present application, the battery pack 100 further comprises a transformer 3, an eleventh switch K11, a twelfth switch K12, a thirteenth switch K13 and a fourteenth switch K14. The transformer 3 comprises a first transformer part 31 and a second transformer part 32. The first end of the first transformer part 31 is electrically connected with the first end of the first switch 21 and the first end of the second switch 22 respectively, and the second end of the first transformer part 31 is electrically connected with the second end of the first switch 21 and the second end of the second switch 22 respectively. The first end of the second transformer part 32 is electrically connected with the first interface 41 of the electric energy interface 4, and the second end of the second transformer part 32 is electrically connected with the second interface 42 of the electric energy interface 4.

[0190] The first end of the eleventh switch K11 is electrically connected with the positive pole of the first battery 11, the first end of the first switch 21, the first end of the second switch 22 and the first end of the first transformer part 31 respectively, and the second end of the eleventh switch K11 is electrically connected with the first interface 41 of the electric energy interface 4. The first end of the twelfth switch K12 is electrically connected with the negative pole of the second battery 12, the second end of the third switch 23, the second end of the fourth switch 24 and the second end of the first transformer part 31 respectively, and the second end of the twelfth switch K12 is electrically connected with the second interface 42 of the electric energy interface 4. The first end of the thirteenth switch K13 is electrically connected with the positive pole of the first battery 11, the first end of the first switch 21, the first end of the second switch 22 and the first end of the eleventh switch K11, and the second end of the thirteenth switch K13 is electrically connected with the first end of the first transformer part 31. The first end of the fourteenth switch K14 is electrically connected with the second end of the eleventh switch K11 and the first interface 41 of the electric energy interface 4 respectively, and the second end of the fourteenth switch K14 is electrically connected with the first end of the second transformer part 32.

[0191] When the battery pack 100 is connected in parallel with the current network 200 of the energy storage system 1000, the eleventh switch K11 and the twelfth switch K12 are closed, and the thirteenth switch K13 and the fourteenth switch K14 are opened. At this time, the first battery 11 and the second battery 12 are directly connected with the power interface 4. When the battery pack 100 outputs direct current to the outside, the eleventh switch K11 and the twelfth switch K12 are opened, and the thirteenth switch K13 and the fourteenth switch K14 are closed. The transformer 3 is connected between the power interface 4 and the first battery 11 and the second battery 12. The current of the first battery 11 and the second battery 12 can be output to the power interface 4 after being transformed by the transformer 3, and the current input by the power interface 4 can also be input to the first battery 11 and the second battery 12 after being transformed by the transformer 3. In this way, the voltage output by the battery pack 100 to the outside or the voltage input by the energy storage system 1000 to the battery pack 100 can be kept within the suitable range of the battery pack 100 and the energy storage system 1000, thereby improving the stability of the current work of the battery pack 100.

[0192] The battery pack 100 further comprises a third inductor L3, a first end of the third inductor L3 being connected with a second end of the eleventh switch K11, and a second end of the third inductor L3 being connected with a first end of the first transformer part 31. The third inductor L3 can balance the current and voltage on the high-voltage side or the low-voltage side of the transformer 3, improve the stability of the current transmission of the transformer 3, and reduce the loss of the current in the transformer 3.

[0193] In order to avoid that the current of the battery pack 100 burns the electrical device when the battery pack 100 is connected with the electrical device, in an embodiment of the present application, the battery pack 100 further comprises a fifteenth switch K15 and a first resistor R1. A first end of the fifteenth switch K15 is electrically connected with a positive electrode of the first battery 11 and a first end of the fifth switch. A second end of the fifteenth switch K15 is electrically connected with a first end of the first resistor R1. A second end of the first resistor R1 is electrically connected with a second end of the fifth switch, a first end of the first switch 21, a first end of the second switch 22, and a first interface 41 of the power interface 4, respectively.

[0194] When the battery pack 100 is connected with the electrical device, the fifth switch is opened, and the fifteenth switch K15 is closed. The first resistor R1 is connected between the battery pack 100 and the electrical device through the fifteenth switch K15. In this way, the circuit resistance is increased, and the circuit current is reduced, thereby protecting the electrical device. When the current of the battery pack 100 is stable, the fifth switch is closed, and the fifteenth switch K15 is opened. The first resistor R1 is disconnected from the circuit of the battery pack 100.

[0195] The battery pack 100 further comprises a capacitor C and a seventeenth switch K17, a first end of the seventeenth switch K17 is electrically connected with the positive pole of the first battery 11, the first end of the first switch 21, the first end of the second switch 22 and the first interface 41 of the electric energy interface 4 respectively, and a second end of the seventeenth switch K17 is electrically connected with a first end of the capacitor C; a second end of the capacitor C is electrically connected with the negative pole of the second battery 12, the second end of the third switch 23, the second end of the fourth switch 24 and the second interface 42 of the electric energy interface 4 respectively. When the battery pack 100 outputs direct current to the outside, the twelfth switch K12 is closed, and the capacitor C is connected into the circuit of the battery pack 100. The capacitor C is used for filtering the current delivered by the first battery 11 and the second battery 12 to the electric energy interface 4, so as to ensure the stability of the current delivered by the battery pack 100 to the electrical device. At the same time, when the first battery 11 charges the first inductor L1, the capacitor C can temporarily replace the first battery 11 and the first inductor L1 to supply power to the electrical device, so as to improve the stability of the current supply of the battery pack 100.

[0196] The battery pack 100 further comprises a seventeenth switch K17 and a second resistor R2, a first end of the seventeenth switch K17 is electrically connected with the first end of the capacitor C, and a second end of the seventeenth switch K17 is electrically connected with a first end of the second resistor R2. A second end of the second resistor R2 is electrically connected with the second end of the capacitor C. When the battery pack 100 stops delivering current to the outside, the seventeenth switch K17 is closed, and the capacitor C and the second resistor R2 are connected in series with each other, so as to discharge the excess voltage on the capacitor C and protect the circuit.

[0197] Please refer to FIG. 17, the battery pack further comprises a controller 300, a communication bus 1001, a user interface 1002, a network interface 1003 and a memory 1004, the communication bus 1001 is used for realizing the connection communication between the components. The user interface 1002 is mainly applied to the user for data interaction, and the user interface 1002 can comprise a display screen (Display) and an input unit such as a keyboard (Keyboard), and optionally the user interface 1002 can further comprise a standard wired interface and a wireless interface. The network interface 1003 is mainly applied to the network server for data communication, and the network interface 1003 can optionally comprise a standard wired interface and a wireless interface (such as a wireless fidelity (Wireless-Fidelity, Wi-Fi) interface).

[0198] The controller 300 is configured to invoke computer instructions to perform the control method of the battery pack. The controller 300 can be a central processing unit (CPU), and can also be other general controllers, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0199] In an embodiment of the present application, the controller 300 includes a first controller and a second controller. The first controller is configured to control the opening and closing of the first back door, and the second controller is configured to control the opening and closing of the second back door.

[0200] The memory 1004 is configured to store computer instructions, and the memory 1004 is configured to store operating systems, network communication modules, user interface modules, and control programs of the battery pack, etc. The memory 1004 can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM) used as an external cache. By way of example, but not limitation, many forms of RAM can be used, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus random access memory (DR RAM).

[0201] It should be noted that when the controller 300 is a general controller, a DSP, an ASIC, a FPGA or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, the memory (storage module) is integrated in the controller.

[0202] It should be noted that the memory described herein is intended to include, but not limited to, these and any other suitable type of memory.

[0203] The bus can include, in addition to the data bus, a power bus, a control bus, and a status signal bus, etc. However, for the sake of clarity, all the buses are marked as bus in the figure.

[0204] Referring to FIG. 18, FIG. 18 is a flow diagram of a first embodiment of a battery pack control method provided by the present application, the control method is applied to the battery pack, and the battery pack control method comprises:

[0205] S10, control the battery to deliver direct current to the power interface.

[0206] S20, change the current direction of the battery flowing to the power interface by reciprocating the state of the switch group, to output alternating current to the power interface.

[0207] The application improves the control method of the battery pack, solves the problem of connecting the battery pack and the energy storage power station in grid without adding additional electrical elements and without equipping additional inverters, and reduces the cost of connecting the battery pack and the energy storage power station in grid.

[0208] Please refer to FIG. 19, in an embodiment of the application, changing the current direction of the battery flowing to the power interface by reciprocating the state of the switch group includes the following steps:

[0209] S201, control the positive electrode of the battery to be connected with the first interface, and the negative electrode of the battery to be connected with the second interface, so that the switch group enters the first state.

[0210] In an embodiment of the application, controlling the positive electrode of the battery to be connected with the first interface and the negative electrode of the battery to be connected with the second interface includes the following steps:

[0211] Control the first switch and the fourth switch to be closed, and control the second switch and the third switch to be opened.

[0212] It can be understood that in other embodiments of the application, additional switches can be added to control the positive electrode of the battery to be connected with the first interface and the negative electrode of the battery to be connected with the second interface, and compared with other ways, the number of switches used in the embodiment is the least, and the cost is more economical.

[0213] S202, control the negative electrode of the battery to be connected with the first interface, and the negative electrode of the battery to be connected with the second interface, so that the switch group enters the second state.

[0214] In an embodiment of the application, controlling the negative electrode of the battery to be connected with the first interface and the negative electrode of the battery to be connected with the second interface includes the following steps:

[0215] Control the second switch and the third switch to be closed, and control the first switch and the fourth switch to be opened.

[0216] It can be understood that in other embodiments of the application, additional switches can be added to control the negative electrode of the battery to be connected with the first interface and the negative electrode of the battery to be connected with the second interface, and compared with other ways, the number of switches used in the embodiment is the least, and the cost is more economical.

[0217] S203, reciprocate the switch group between the first state and the second state.

[0218] The embodiment realizes the conversion of the battery pack from AC to DC without adding additional electrical elements, and reduces the grid connection cost of the battery pack.

[0219] Please refer to FIG. 20, which is a flowchart of a second embodiment of the control method of the battery pack provided by the present application. Compared with the first embodiment, the difference of the present embodiment is that the control method of the battery pack further includes:

[0220] S30, control the battery and the inductor in series to make the switch group enter the third state.

[0221] In an implementable embodiment of the present application, the step of controlling the battery and the inductor in series to make the switch group enter the third state includes:

[0222] controlling the first switch to be closed and the second switch to be opened.

[0223] It can be understood that in other implementable embodiments of the present application, additional switches can be added to realize the series connection of the battery and the inductor. Compared with other ways, the present embodiment uses the least number of switch groups, and is more cost-saving.

[0224] S40, control the battery and the inductor in series with the power interface to make the switch group enter the fourth state.

[0225] The step of controlling the battery and the inductor in series with the power interface to make the switch group enter the fourth state includes:

[0226] controlling the first switch and the second switch to be closed.

[0227] It can be understood that in other implementable embodiments of the present application, additional switches can be added to realize the series connection of the inductor and the power interface. Compared with other ways, the present embodiment uses the least number of switch groups, and is more cost-saving.

[0228] S50, control the switch group to reciprocally switch between the third state and the fourth state.

[0229] The present embodiment improves the application scenarios of the battery pack and prolongs the service life of the battery pack by controlling the switch group of the battery pack, so that the battery can supply power to the power-consuming device by boosting the voltage in the case of insufficient voltage, or the inductor can supply power to the power-consuming device instead of the battery in the case of insufficient power of the battery.

[0230] Please refer to FIG. 21, which is a flowchart of a third embodiment of the control method of the battery pack provided by the present application. Compared with the first embodiment, the difference of the present embodiment is that when the difference between the charge amount of the first battery and the charge amount of the second battery is greater than a preset threshold, the control method of the battery pack further includes:

[0231] S60, control the first battery and the inductor in series through the switch group, so that the switch group enters a fifth state.

[0232] In an embodiment of the present application, the step of controlling the first battery and the inductor in series through the switch group, so that the switch group enters a fifth state, comprises the steps of:

[0233] controlling the first switch to be closed and the second switch to be opened.

[0234] It can be understood that, in other embodiments of the present application, switches can be additionally added to achieve the control of the first battery charging the inductor, and compared with other modes, the number of switch groups used in the embodiment is the least, and the cost is more economical.

[0235] S70, control the inductor and the second battery in series through the switch group, so that the switch group enters a sixth state.

[0236] In an embodiment of the present application, the step of controlling the inductor and the second battery in series through the switch group, so that the switch group enters a sixth state, comprises the steps of:

[0237] controlling the first switch to be opened and the second switch to be closed.

[0238] It can be understood that, in other embodiments of the present application, switches can be additionally added to achieve the control of the inductor and the second battery in series, and compared with other modes, the number of switch groups used in the embodiment is the least, and the cost is more economical.

[0239] S80, control the switch group to reciprocate between the fifth state and the sixth state.

[0240] In the embodiment, the controller monitors the charge amount of the first battery and the second battery, and when the controller monitors that the difference between the charge amount of the first battery and the charge amount of the second battery is greater than a preset threshold, the controller controls the switch group to reciprocate between the fifth state and the sixth state, so as to charge the second battery. In this way, the pressure difference between the first battery and the second battery is stabilized, and the service life of the battery is improved.

[0241] Please refer to FIG. 22, which is a flow diagram of a fourth embodiment of the battery pack control method provided by the present application. Compared with the first embodiment, the difference of the present embodiment is that when the difference between the charge amount of the second battery and the charge amount of the first battery is greater than a preset threshold, the battery pack control method further comprises:

[0242] S90, control the second battery and the inductor in series through the switch group, so that the switch group enters a seventh state.

[0243] In an embodiment of the present application, the step of controlling the second battery and the inductor in series through the switch group, so that the switch group enters a seventh state, comprises the steps of:

[0244] controlling the first switch to be closed and the second switch to be opened.

[0245] It can be understood that, in other embodiments of the present application, switches can be additionally added to achieve the control of the second battery and the inductor in series, and compared with other modes, the number of switch groups used in the embodiment is the least, and the cost is more economical.

[0246] S100, controlling the first battery and the inductor in series through the switch group, so that the switch group enters an eighth state.

[0247] In an embodiment of the present application, controlling the first battery and the inductor in series through the switch group, so that the switch group enters an eighth state includes the steps of:

[0248] controlling the first switch to be closed and the second switch to be opened.

[0249] It can be understood that, in other embodiments of the present application, switches can be additionally added to achieve the control of the first battery and the inductor in series, and compared with other modes, the number of switch groups used in the embodiment is the least, and the cost is more economical.

[0250] S110, controlling the switch group to reciprocate between the seventh state and the eighth state.

[0251] In the embodiment, the controller monitors the charge amount of the first battery and the second battery, and when the controller monitors that the difference between the charge amount of the second battery and the charge amount of the first battery is greater than a preset threshold, the controller controls the switch group to switch between the seventh state and the eighth state, thereby charging the first battery. In this way, the pressure difference between the first battery and the second battery is stabilized, and the service life of the battery is improved.

[0252] In the description of the embodiments of the present application, it should be noted that the terms “center”, “upper”, “lower”, “left”, “right”, “vertical”, “horizontal”, “inner”, “outer” and the like indicate the orientation or positional relationship based on the drawings described, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0253] Having described various embodiments of the application, it is to be understood that the above description is meant not to be exhaustive or limited to the various embodiments disclosed. Many modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the described embodiments. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the various embodiments described herein, which will be limited only by the appended claims.

Claims

1. A battery pack, wherein, It includes a battery (1), a switch assembly (2) and a power interface (4), wherein the switch assembly (2) is electrically connected to the battery (1) and the power interface (4) respectively; The switch group (2) is used to control the battery (1) to supply DC current to the power interface (4); The switch group (2) is used to switch states repeatedly under the control of the battery pack (100) to change the direction of the current flowing from the battery (1) to the power interface (4) so ​​as to output AC power to the power interface (4).

2. The battery pack as claimed in claim 1, wherein, The power interface (4) includes a first interface (41) and a second interface (42). The switch group (2) has a first state and a second state. The switch group (2) is used to switch back and forth between the first state and the second state so that the power interface (4) outputs AC power. In the first state, the battery pack (100) controls the positive terminal of the battery (1) to be connected to the first interface (41) and the negative terminal of the battery (1) to be connected to the second interface (42); In the second state, the battery pack (100) controls the negative terminal of the battery (1) to be connected to the first interface (41) and the negative terminal of the battery (1) to be connected to the second interface (42).

3. The battery pack as described in claim 2, wherein, The switch group (2) includes a first switch (21), a second switch (22), a third switch (23), and a fourth switch (24); the first end of the first switch (21) is connected to the positive terminal of the battery (1), the first end of the second switch (22) is connected to the first interface (41), and the second end of the first switch (21) is connected to the first end of the third switch (23). The second end of the second switch (22) is connected to the first end of the fourth switch (24); the second end of the third switch (23) is connected to the negative terminal of the battery (1), the second end of the fourth switch (24), and the second interface (42) respectively; In the first state, the battery pack (100) controls the first switch (21) and the fourth switch (24) to close; and controls the second switch (22) and the third switch (23) to open; In the second state, the battery pack (100) controls the second switch (22) and the third switch (23) to close, and controls the first switch (21) and the fourth switch (24) to open.

4. The battery pack as claimed in claim 1, wherein, The battery pack (100) also includes an inductor, which is electrically connected to the battery (1) and the switch group (2) respectively; the switch group (2) also has a third state and a fourth state, and the switch group (2) is also used to switch the third state and the fourth state repeatedly to control the battery to boost the power supply to the power interface (4); In the third state, the battery (1) is connected in series with the inductor to charge the inductor; In the fourth state, the battery (1) and the inductor are connected in series with the power interface (4) to jointly supply power to the power interface (4).

5. The battery pack as claimed in claim 4, wherein, The power interface (4) includes a first interface (41) and a second interface (42), and the switch group (2) includes a first switch (21) and a second switch (22); the first end of the first switch (21) is connected to the positive terminal of the battery (1) and the first interface (41) respectively; the first end of the inductor is connected to the negative terminal of the battery (1), and the second end of the inductor is connected to the first end of the second switch (22); the second end of the second switch (22) is connected to the second interface (42); In the third state, the battery pack (100) controls the first switch (21) to close and the second switch (22) to open; In the fourth state, the battery pack (100) controls the first switch (21) and the second switch (22) to close.

6. The battery pack as claimed in claim 1, wherein, The battery pack (100) also includes an inductor. The battery pack (100) includes a first battery (11) and a second battery (12) that are electrically connected to each other. The negative terminal of the first battery (11) is electrically connected to the positive terminal of the second battery (12). The first end of the inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12), respectively. The second end of the inductor is connected to the switch group (2). The switch group (2) also has a fifth state and a sixth state, and the switch group (2) is also used to repeatedly switch the fifth state and the sixth state to make the first battery (11) and the second battery (12) equalize voltage; In the fifth state, the battery pack (100) controls the first battery (11) to be connected in series with the inductor via the switch group (2); In the sixth state, the battery pack (100) controls the first inductor to be connected in series with the second battery (12) through the switch group (2) so as to charge the second battery (12) through the first inductor.

7. The battery pack as claimed in claim 6, wherein, The switch group (2) includes a first switch (21) and a second switch (22); the first end of the first switch (21) is connected to the positive terminal of the first battery (11); the first end of the inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12); the second end of the inductor is connected to the second end of the first switch (21) and the first end of the second switch (22); the second end of the second switch (22) is connected to the negative terminal of the second battery (12). In the fifth state, the battery pack (100) controls the first switch (21) to close and the second switch (22) to open; In the sixth state, the battery pack (100) controls the first switch (21) to open and the second switch (22) to close.

8. The battery pack as claimed in claim 6, wherein, The inductor also includes a first inductor and a second inductor; in the fifth state, the battery pack (100) also controls the second inductor to be connected in series with the second battery (12) through the switch group (2) so as to charge the second battery (12) through the second inductor; In the sixth state, the battery pack (100) also controls the second inductor to be connected in series with the first battery (11) through the switch group (2) so that the second inductor is charged by the first battery (11).

9. The battery pack as claimed in claim 8, wherein, The switch group (2) includes a first switch (21), a second switch (22), a third switch (23), and a fourth switch (24); the first end of the first switch (21) is connected to the positive terminal of the first battery (11) and the first end of the second switch (22), respectively; The first end of the first inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12), respectively, and the second end of the first inductor is connected to the second end of the first switch (21) and the first end of the third switch (23), respectively. The first end of the second inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12), respectively; the second end of the second inductor is connected to the second end of the second switch (22) and the first end of the fourth switch (24), respectively; the second end of the third switch (23) is connected to the negative terminal of the second battery (12) and the second end of the fourth switch (24), respectively. In the fifth state, the battery pack (100) controls the first switch (21) and the fourth switch (24) to close, and controls the second switch (22) and the third switch (23) to open; In the sixth state, the battery pack (100) controls the second switch (22) and the third switch (23) to close, and controls the first switch (21) and the fourth switch (24) to open.

10. The battery pack of claim 6, wherein, The switch group (2) has a seventh state and an eighth state, and the switch group (2) also switches back and forth between the seventh state and the eighth state to make the first battery (11) and the second battery (12) equalize voltage; In the seventh state, the battery pack (100) controls the second battery (12) to be connected in series with the first inductor through the switch group (2) so that the first inductor is charged by the second battery (12); In the eighth state, the battery pack (100) controls the first battery (11) to be connected in series with the first inductor through the switch group (2) so as to charge the first battery (11) through the first inductor.

11. The battery pack of claim 10, wherein, The switch group (2) includes a first switch (21) and a second switch (22); the first end of the first switch (21) is connected to the positive terminal of the first battery (11); the first end of the inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12); the second end of the inductor is connected to the second end of the first switch (21) and the first end of the second switch (22); the second end of the second switch (22) is connected to the negative terminal of the second battery (12). In the seventh state, the battery pack (100) controls the first switch (21) to open and the second switch (22) to close; In the eighth state, the battery pack (100) controls the first switch (21) to close and the second switch (22) to open.

12. The battery pack of claim 10, wherein, The inductor also includes a first inductor and a second inductor; in the seventh state, the battery pack (100) also controls the second inductor to be connected in series with the first battery (11) through the switch group (2) so as to charge the first battery (11) through the second inductor; In the eighth state, the battery pack (100) also controls the second inductor to be connected in series with the second battery (12) through the switch group (2) so that the second inductor is charged by the second battery (12).

13. The battery pack of claim 12, wherein, The switch group (2) includes a first switch (21), a second switch (22), a third switch (23), and a fourth switch (24); the first end of the first switch (21) is connected to the positive terminal of the first battery (11) and the first end of the second switch (22), respectively; The first end of the first inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12), respectively, and the second end of the first inductor is connected to the second end of the first switch (21) and the first end of the third switch (23), respectively. The first end of the second inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12), respectively, and the second end of the second inductor is connected to the second end of the second switch (22) and the first end of the fourth switch (24), respectively. The second end of the third switch (23) is connected to the negative terminal of the second battery (12) and the second end of the fourth switch (24), respectively. In the seventh state, the battery pack controls the third switch (23) and the fourth switch (24) to close, and controls the first switch (21) and the second switch (22) to open; In the eighth state, the battery pack controls the first switch (21) and the fourth switch (24) to close, and controls the second switch (22) and the third switch (23) to open.

14. The battery pack according to any one of claims 8-13, wherein, The battery pack also includes a fifth switch, a sixth switch, a seventh switch and an eighth switch. The first end of the fifth switch is electrically connected to the positive terminal of the first battery (11) and the first end of the seventh switch, respectively. The second end of the fifth switch is electrically connected to the first end of the first switch (21), the first end of the second switch (22) and the first interface (41) of the power interface (4), respectively. The first end of the sixth switch is electrically connected to the negative terminal of the second battery (12) and the first end of the eighth switch. The second end of the sixth switch is electrically connected to the second end of the fifth switch, the second end of the sixth switch and the second interface (42) of the power interface (4). The second end of the seventh switch is electrically connected to the second end of the first switch (21) and the first end of the fifth switch, respectively; the second end of the eighth switch is electrically connected to the second end of the second switch (22) and the first end of the sixth switch, respectively.

15. The battery pack of claim 14, wherein, The switch group (2) has a first state and a second state. The switch group (2) is used to switch back and forth between the first state and the second state so that the power interface (4) outputs AC power. The switch group (2) also has a third state and a fourth state, and the switch group (2) is also used to switch the third state and the fourth state repeatedly to control the battery (100) to boost the power supply to the power interface (4); The battery pack (100) controls the fifth and sixth switches to be open, and the seventh and eighth switches to be closed, so that the switch group (2) can be used to switch back and forth between the first and second states; The battery pack (100) controls the fifth and sixth switches to close, and the seventh and eighth switches to open, so that the switch group (2) is used to switch back and forth between the third and fourth states.

16. A control method for a battery pack, the control method being applied to a battery pack (100) comprising a battery, a switch group (2), and a power interface (4), the switch group (2) being electrically connected to the battery and the power interface (4) respectively; the switch group (2) being used to control the battery (1) to supply DC current to the power interface (4); the switch group (2) being used to repeatedly switch states under the control of the battery pack to change the direction of the current flowing from the battery to the power interface (4) so ​​as to output AC current to the power interface (4), wherein, The control method for the battery pack includes the following steps: Control the battery (1) to supply DC power to the power interface (4); By repeatedly switching the state of the switch group (2), the direction of the current flowing from the battery (1) to the power interface (4) is changed, so as to output AC power to the power interface (4).

17. The battery pack control method as described in claim 16, wherein, The power interface (4) includes a first interface (41) and a second interface (42). The step of changing the direction of the current flowing from the battery (1) to the power interface (4) by repeatedly switching the state of the switch group (2) includes the following steps: The positive terminal of the battery (1) is connected to the first interface (41), and the negative terminal of the battery is connected to the second interface (42) so that the switch group (2) enters the first state; The negative terminal of the battery (1) is connected to the first interface (41) and the negative terminal of the battery (1) is connected to the second interface (42) so that the switch group (2) enters the second state; The switch group (2) is controlled to switch back and forth between the first state and the second state.

18. The battery pack control method as described in claim 17, wherein, The switch group (2) includes a first switch (21), a second switch (22), a third switch (23), and a fourth switch (24); the first end of the first switch (21) is connected to the positive terminal of the battery (1), the first end of the second switch (22), and the first interface (41); the second end of the first switch (21) is connected to the first end of the third switch (23); the second end of the second switch (22) is connected to the first end of the fourth switch (24); the second end of the third switch (23) is connected to the negative terminal of the battery (1), the second end of the fourth switch (24), and the second interface (42). The steps of connecting the positive terminal of the battery (1) to the first interface (41) and the negative terminal of the battery (1) to the second interface (42) include: Control the first switch (21) and the fourth switch (24) to close; control the second switch (22) and the third switch (23) to open; The steps of connecting the negative terminal of the battery (1) to the first interface (41) and connecting the negative terminal of the battery (1) to the second interface (42) include: Control the second switch (22) and the third switch (23) to close, and control the first switch (21) and the fourth switch (24) to open.

19. The battery pack control method as described in claim 16, wherein, The battery pack (100) further includes an inductor, which is electrically connected to the battery and the switch group (2) respectively; the control method of the battery pack further includes: Control the battery to be connected in series with the inductor so that the switch group (2) enters the third state; Control the battery and the inductor to be connected in series with the power interface (4) so ​​that the switch group (2) enters the fourth state; Control the switch group (2) to switch back and forth between the third state and the fourth state.

20. The battery pack control method as described in claim 19, wherein, The power interface (4) includes a first interface (41) and a second interface (42), and the switch group (2) includes a first switch (21) and a second switch (22); the first end of the first switch (21) is connected to the positive terminal of the battery and the first interface (41) respectively; the first end of the inductor is connected to the negative terminal of the battery, and the second end of the inductor is connected to the first end of the second switch (22); the second end of the second switch (22) is connected to the second interface (42); The steps of controlling the battery (1) to be connected in series with the inductor to cause the switch group (2) to enter the third state include: Control the first switch (21) to close and the second switch (22) to open; The steps of controlling the battery (1) and the inductor to be connected in series with the power interface (4) to bring the switch group (2) into the fourth state include: Control the first switch (21) and the second switch (22) to close.

21. The battery pack control method as described in claim 16, wherein, The battery pack also includes an inductor. The battery (1) includes a first battery (11) and a second battery (12) that are electrically connected to each other. The negative terminal of the first battery (11) is electrically connected to the positive terminal of the second battery (12). The first end of the inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12), respectively. The second end of the inductor is connected to the switch group (2). When the difference between the charge of the first battery (11) and the charge of the second battery (12) is greater than a preset threshold, the control method of the battery pack further includes: The first battery (11) is connected in series with the inductor by the switch group (2) so that the switch group (2) enters the fifth state; The inductor is connected in series with the second battery (12) by the switch group (2) so that the switch group (2) enters the sixth state; Control the switch group (2) to switch back and forth between the fifth state and the sixth state.

22. The battery pack control method as described in claim 21, wherein, The switch group (2) includes a first switch (21) and a second switch (22); the first end of the first switch (21) is connected to the positive terminal of the first battery (11); the first end of the inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12); the second end of the inductor is connected to the second end of the first switch (21) and the first end of the second switch (22); the second end of the second switch (22) is connected to the negative terminal of the second battery (12). The step of controlling the first battery (11) in series with the inductor through the switch group (2) to put the switch group (2) into the fifth state includes the following steps: Control the first switch (21) to close and the second switch (22) to open; The step of controlling the inductor to be connected in series with the second battery (12) through the switch group (2) to put the switch group (2) into the sixth state includes the following steps: The first switch (21) is opened and the second switch (22) is closed.

23. The battery pack control method as described in claim 16, wherein, The battery pack also includes an inductor. The battery includes a first battery (11) and a second battery (12) that are electrically connected to each other. The negative terminal of the first battery (11) is electrically connected to the positive terminal of the second battery (12). The first end of the inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12), respectively. The second end of the inductor is connected to the switch group (2). When the difference between the charge of the second battery (12) and the charge of the first battery (11) is greater than a preset threshold, the control method of the battery pack further includes: The second battery (12) is connected in series with the inductor by the switch group (2) so that the switch group (2) enters the seventh state; The first battery (11) is connected in series with the inductor by the switch group (2) so that the switch group (2) enters the eighth state; The switch group (2) is controlled to switch back and forth between the seventh state and the eighth state.

24. The battery pack control method as described in claim 23, wherein, The switch group (2) includes a first switch (21) and a second switch (22); the first end of the first switch (21) is connected to the positive terminal of the first battery (11); the first end of the inductor is connected to the negative terminal of the first battery (11) and the positive terminal of the second battery (12); the second end of the inductor is connected to the second end of the first switch (21) and the first end of the second switch (22); the second end of the second switch (22) is connected to the negative terminal of the second battery (12). The step of controlling the second battery (12) in series with the inductor through the switch group (2) to put the switch group (2) into the seventh state includes the following steps: The first switch (21) is opened and the second switch (22) is closed. The step of controlling the first battery (11) in series with the inductor through the switch group (2) to put the switch group (2) into the eighth state includes the following steps: Control the first switch (21) to close and the second switch (22) to open.

25. An electrical energy device, wherein, Includes the battery pack (100) as described in any one of claims 1-15.

26. An energy storage system, wherein, include: Current network (200); and At least one battery pack (100) as described in any one of claims 1-15, wherein the battery pack (100) is electrically connected to the current network (200).

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