Vehicle energy storage device, vehicle

Abstract

This application discloses a vehicle energy storage device and a vehicle. The vehicle energy storage device includes a power battery pack, a voltage conversion circuit, and a main control circuit. The power battery pack is connected to a first power supply terminal via the voltage conversion circuit, and the main control circuit is connected to the voltage conversion circuit. The main control circuit is used to adjust the working state of the voltage conversion circuit according to the parameters of the first power supply terminal and the power battery pack, so as to maintain the stability of the DC bus voltage when the voltage of the power battery pack is low or when the DC bus voltage is pulled down due to vehicle acceleration, thereby enabling the vehicle to maintain high power.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, specifically to a vehicle energy storage device and a vehicle. Background Technology

[0002] With the rapid development of new energy vehicles, increasing battery voltage has become an important research and development trend in order to provide stronger power. Typically, the voltage of the power batteries installed in new energy vehicles can reach 800V or even higher.

[0003] However, the voltage range of power battery packs composed of sodium-ion, lithium-ion, or hybrid batteries in related technologies is very wide, which requires high-voltage electrical appliances to be compatible with a wide voltage range. However, at low voltage, there are problems such as insufficient power and insufficient power output of high-voltage electrical appliances. Summary of the Invention

[0004] In view of the above problems, this application provides a vehicle energy storage device and a vehicle, which can solve the problem of slow discharge speed of energy storage devices in related technologies, which poses safety hazards.

[0005] The first aspect of this application provides a vehicle energy storage device, which includes: a power battery pack, a voltage conversion circuit, and a main control circuit;

[0006] The power battery pack is connected to the first power supply terminal via the voltage conversion circuit;

[0007] The main control circuit is connected to the voltage conversion circuit and is used to adjust the working state of the voltage conversion circuit according to the parameters of the first power supply terminal and the power battery pack.

[0008] In the technical solution of this application embodiment, the parameters of the first power supply terminal and the power battery pack are obtained through the main control circuit, and the working state of the voltage conversion circuit is adjusted according to the parameters of the first power supply terminal and the power battery pack. In this way, when the voltage of the power battery pack is low, or when the DC bus voltage is pulled down due to vehicle acceleration, resulting in a low voltage of the first power supply terminal, the voltage conversion circuit maintains the stability of the DC bus voltage, so that the vehicle maintains high power.

[0009] In some embodiments, the power battery pack includes a sodium-ion battery pack, a lithium-ion battery pack, and a switching circuit. The sodium-ion battery pack and the lithium-ion battery pack are respectively connected to the switching circuit, and the switching circuit is used to control the sodium-ion battery pack and the lithium-ion battery pack to be connected in series or in parallel.

[0010] In the technical solution of this application embodiment, the switching circuit is used to control the sodium-ion battery pack and the lithium-ion battery pack to be connected in series or in parallel. The power battery pack formed by sodium-ion battery packs, lithium-ion battery packs, or a mixture of sodium-ion battery packs and lithium-ion battery packs has a wide voltage range. Therefore, high-voltage electrical appliances are required to adapt to the wide voltage range. However, at low voltage, the power is insufficient, and there is a problem of insufficient power output of the high-voltage electrical appliances. By integrating a voltage conversion circuit with buck-boost function into the powertrain, not only can the capacitor on the low-voltage side be saved, but also when the output voltage of the power battery pack is low, or when the DC bus voltage is pulled down due to vehicle acceleration, resulting in a low voltage at the first power supply terminal, the voltage conversion circuit can maintain the stability of the DC bus voltage, so that the vehicle maintains high power.

[0011] In some embodiments, the main control circuit is further configured to control the voltage conversion circuit to boost the voltage provided by the power battery pack when the voltage at the first power supply terminal is lower than a first preset threshold voltage or the voltage of the power battery pack is lower than a second preset threshold voltage, so as to keep the voltage at the first power supply terminal within a first preset voltage range.

[0012] In the technical solution of this application embodiment, one end of the voltage conversion circuit is connected to the power battery pack, and the other end is connected to the first power supply terminal. When the voltage of the power battery pack or the voltage of the first power supply terminal is low, the voltage provided by the power battery pack can be boosted by controlling the voltage conversion circuit to keep the voltage of the first power supply terminal within a first preset voltage range, thus maintaining the stability of the DC bus voltage and enabling the vehicle to maintain high power. For example, one end of the voltage conversion circuit is connected to the power battery pack, and the other end is connected to the high-voltage distribution box in the first power supply terminal. The high-voltage distribution box supplies power to the connected load according to the voltage output from the power supply side of the voltage conversion circuit. When the voltage of the power battery pack or the voltage of the first power supply terminal is low, the input voltage of the high-voltage distribution box is low. The voltage provided by the power battery pack can be boosted by controlling the voltage conversion circuit to keep the voltage of the first power supply terminal within a first preset voltage range, thus maintaining the stability of the DC bus voltage and enabling the vehicle to maintain high power.

[0013] In some embodiments, the main control circuit is further configured to control the voltage conversion circuit to step down the voltage provided by the first power supply terminal when the voltage connected to the first power supply terminal is greater than a third preset threshold voltage, so as to increase the charging current of the power battery pack by the voltage conversion circuit.

[0014] In the technical solution of this application embodiment, if the voltage connected to the first power supply terminal is too high when the vehicle is charging, the voltage provided by the first power supply terminal can be reduced by a voltage conversion circuit to increase the charging current of the power battery pack, expand the application scenarios of vehicle charging, and maximize the use of the charging power of the charging pile.

[0015] In some embodiments, the voltage conversion circuit includes at least one half-bridge, the midpoint of at least one half-bridge is connected to the positive terminal of the power battery pack, and the negative busbar of at least one half-bridge is connected to the negative terminal of the power battery pack.

[0016] In the technical solution of this application embodiment, by setting the midpoint of the half-bridge to be connected to the positive terminal of the power battery pack and the negative busbar of the half-bridge to be connected to the negative terminal of the power battery pack, the voltage between the power battery pack and the first power supply terminal can be converted.

[0017] In some embodiments, the voltage conversion circuit further includes a first inductor, and at least one half-bridge midpoint is connected to the positive terminal of the power battery pack via the first inductor.

[0018] In the technical solution of this application embodiment, by setting the midpoint of the half-bridge to be connected to the positive terminal of the power battery pack via the first inductor, and the negative busbar of the half-bridge to be connected to the negative terminal of the power battery pack, the voltage between the power battery pack and the first power supply terminal can be converted. Each arm of the half-bridge can be controlled independently. When a high-voltage electrical appliance experiences a short circuit, the short-circuit current rises more slowly due to the presence of the first inductor. The main control circuit (e.g., the power control unit) can detect the overcurrent and shut down the semiconductor switching elements of the buck-boost module in microseconds, cutting off the high-voltage circuit faster than a fuse.

[0019] In some embodiments, the voltage conversion circuit includes: a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, and a common-mode inductor;

[0020] The first terminal of the first switch and the first terminal of the second switch are both connected to the first terminal of the common-mode inductor. The first terminal of the third switch and the first terminal of the fourth switch are both connected to the second terminal of the common-mode inductor. The second terminal of the first switch and the second terminal of the third switch are both connected to the positive terminal of the first power supply terminal. The second terminal of the second switch and the second terminal of the fourth switch are both connected to the negative terminal of the first power supply terminal. The third and fourth terminals of the common-mode inductor are both connected to the positive terminal of the power battery pack.

[0021] In the technical solution of this application embodiment, the first switch, the second switch, the third switch, and the fourth switch form a full-bridge circuit, and the first switch, the second switch, the third switch, the fourth switch, and the common-mode inductor form a boost circuit and a snubber circuit, which can not only realize the voltage conversion between the power battery pack and the first power supply terminal, but also realize rapid active discharge.

[0022] In some embodiments, the vehicle energy storage device further includes a main positive switch and a main negative switch, wherein the positive terminal of the power battery pack is connected to the voltage conversion circuit via the main positive switch, and the negative terminal of the power battery pack is connected to the voltage conversion circuit via the main negative switch.

[0023] In the technical solution of this application embodiment, the positive terminal of the power battery pack is connected to the positive bus of the voltage conversion circuit via the main positive switch, and the negative terminal of the power battery pack is connected to the negative bus of the voltage conversion circuit via the main negative switch. The charging and discharging process of the power battery pack can be controlled by the main positive switch and the main negative switch.

[0024] In some embodiments, the main positive switch and / or the main negative switch comprises a power semiconductor device.

[0025] In the technical solution of this application embodiment, the main positive switch and / or the main negative switch include power semiconductor devices, which can reuse voltage conversion circuits, optimize high voltage architecture, realize abnormal and rapid disconnection of high voltage circuit, eliminate pre-charge relays and pre-charge resistors, and quickly realize active discharge, thereby reducing the cost of the whole vehicle.

[0026] In some embodiments, the main positive switch and / or the main negative switch further includes a diode;

[0027] The diode is connected in reverse parallel with the power semiconductor device.

[0028] In the technical solution of this application embodiment, when the vehicle is involved in a collision, the power semiconductor device can be quickly turned off and the voltage conversion circuit can be quickly stopped from bucking and boosting. Then the voltage conversion circuit enters the active discharge mode and feeds the energy on the output side back to the power battery pack through the diode connected in reverse parallel to the power semiconductor device, thus quickly completing the active discharge.

[0029] In some embodiments, the vehicle energy storage device further includes: a fast charging positive switch and a fast charging negative switch; the first power supply terminal further includes: a second power supply terminal, wherein the positive terminal of the second power supply terminal is connected to the positive bus of the voltage conversion circuit via the fast charging positive switch, and the negative terminal of the second power supply terminal is connected to the negative bus of the voltage conversion circuit via the fast charging negative switch.

[0030] In the technical solution of this application embodiment, a fast charging pile can be connected through the second power supply terminal, and high voltage electricity is connected to the fast charging pile. The high voltage electricity is stepped down and boosted through the voltage conversion circuit, which can make full use of the charging capacity of the charging pile and expand the charging voltage range of the vehicle energy storage device.

[0031] In some embodiments, the vehicle energy storage device further includes a filter capacitor, the two ends of which are respectively connected between the positive and negative power supply buses of the voltage conversion circuit.

[0032] In the technical solution of this application embodiment, by setting the two ends of the filter capacitor to be connected between the positive and negative busbars of the power supply side of the voltage conversion circuit, the voltage of the first power supply terminal can be filtered and the voltage input to the first power supply terminal can be buffered, reducing the voltage fluctuation of the first power supply terminal and improving the power supply stability of the first power supply terminal.

[0033] In some embodiments, the vehicle energy storage device further includes a first current-limiting resistor and a fifth switching transistor, wherein the first current-limiting resistor and the fifth switching transistor are connected in series between the positive and negative terminals on the battery side of the voltage conversion circuit.

[0034] In the technical solution of this application embodiment, by connecting a first current-limiting resistor and a fifth switching transistor in series between the positive and negative terminals on the battery side of the voltage conversion circuit, when the vehicle energy storage device needs to actively discharge, the energy of the filter capacitor can be transferred through the half-bridge, energy storage device, first current-limiting resistor and fifth switching transistor in the voltage conversion circuit to form a freewheeling circuit. Then, the fifth switching transistor is controlled to turn off, and the energy storage device charges the power battery pack. This completes one active discharge cycle, thereby quickly completing the energy dissipation process of the filter capacitor.

[0035] In some embodiments, the vehicle energy storage device further includes an auxiliary power source connected between the positive and negative terminals of the battery side of the voltage conversion circuit.

[0036] In the technical solution of this application embodiment, by setting an auxiliary power supply connected between the positive and negative terminals of the battery side of the voltage conversion circuit, the auxiliary power supply can provide the required electrical energy to the first power supply terminal through the voltage conversion circuit in the event of an abnormality in the power battery pack, thereby improving the power supply stability of the first power supply terminal and reducing safety hazards caused by abnormalities in the power battery pack.

[0037] In some embodiments, the main control circuit is further configured to control the switching duty cycle of the power semiconductor device to gradually increase in the pre-charge mode until the power semiconductor device is fully turned on.

[0038] In the technical solution of this application embodiment, when the main control circuit receives the high voltage power-on command, it first operates in the pre-charge mode. First, it closes the main positive switch and the main negative switch. At least one of the main positive switch and the main negative switch is a power semiconductor device. By controlling the duty cycle of the power semiconductor device to be adjusted from the minimum to a duty cycle of 1, the voltage conversion circuit is started until the high voltage bus of the first power supply terminal reaches the target voltage, thereby sending a ready state to the battery management unit. The vehicle controller sends the power battery ready to continue, completing the power supply pre-charge process.

[0039] In some embodiments, the main control circuit is further configured to control the power semiconductor device to turn off in active discharge mode, so that the energy of the energy storage device in the voltage conversion circuit is fed back to the power battery pack via the diode.

[0040] In the technical solution of this application embodiment, when the vehicle energy storage device needs to discharge quickly, the main control circuit operates in active discharge mode, the power semiconductor device can be quickly turned off, and the voltage conversion circuit can be quickly stopped from bucking and boosting. Then the voltage conversion circuit enters active discharge mode and feeds the energy on the output side back to the power battery pack through the diode connected in reverse parallel to the power semiconductor device, thus quickly completing active discharge.

[0041] In some embodiments, the main control circuit is further configured to control the first switch and the third switch to be turned on, and the second switch and the fourth switch to be turned off, in a pass-through mode.

[0042] In the technical solution of this application embodiment, if the voltage of the power battery pack is consistent with the required voltage of the first power supply terminal, the power battery pack can directly supply power to high-voltage electrical appliances by controlling the first switch and the third switch to be turned on and the second switch and the fourth switch to be turned off. During charging and braking energy recovery, the energy enters the battery directly without going through the step-up and step-down voltage, which can reduce the energy loss caused by the voltage conversion circuit.

[0043] In some embodiments, the main control circuit is further configured to control the main positive switch to turn off in the power-down mode and control the voltage conversion circuit to operate in active discharge mode until the main negative switch is turned off when the voltage at the first power supply terminal is lower than the power-down safety threshold voltage.

[0044] In the technical solution of this application embodiment, after the power battery pack completes the pre-charging process and the voltage conversion circuit operates in direct mode or boost mode, the voltage conversion circuit can be controlled to operate in direct mode first, and then the voltage conversion circuit can be controlled to enter active discharge mode to feed the energy on the output side back to the power battery pack through the diode connected in reverse parallel to the power semiconductor device, until the main negative switch is controlled to turn off when the voltage of the first power supply terminal is lower than the power-down safety threshold voltage.

[0045] In some embodiments, the main control circuit is further configured to control the switching state of the voltage conversion circuit in the regenerative braking mode, so that the reverse current generated by the energy storage device in the voltage conversion circuit charges the power battery pack, and adjust the switching duty cycle of the voltage conversion circuit so that the voltage of the first power supply terminal is maintained within a first preset voltage range.

[0046] In the technical solution of this application embodiment, when the vehicle is driving normally, the voltage conversion circuit works in boost mode, and the voltage of the first power supply terminal is maintained within the first preset voltage range. When braking, the induced electromotive force fed back by the electric drive assembly exceeds the first preset voltage range, causing the current in the inductor to flow in the reverse direction. The main control circuit detects the reverse current direction and adjusts the duty cycle to maintain the DC bus voltage within the first preset voltage range. When the induced voltage fed back by the electric drive is low, the DC bus voltage is lower than the lower limit of the first preset voltage range. The main control circuit then adjusts the duty cycle of the switching transistor in the voltage conversion circuit again to maintain the DC bus voltage within the first preset voltage range.

[0047] A second aspect of this application also provides a vehicle, the vehicle including: a vehicle energy storage device as described in any of the above embodiments.

[0048] In the technical solution of this application embodiment, the vehicle energy storage device includes a power battery pack, a voltage conversion circuit, and a main control circuit. The power battery pack is connected to a first power supply terminal via the voltage conversion circuit, and the main control circuit is connected to the voltage conversion circuit. The main control circuit is used to adjust the working state of the voltage conversion circuit according to the parameters of the first power supply terminal and the power battery pack, so as to maintain the stability of the DC bus voltage when the voltage of the power battery pack is low or the DC bus voltage is pulled down due to vehicle acceleration, so that the vehicle maintains high power. Attached Figure Description

[0049] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0050] Figure 1 This is a schematic diagram of a first structure of a vehicle energy storage device provided in an embodiment of this application;

[0051] Figure 2 This is a schematic diagram of a second structure of the vehicle energy storage device provided in the embodiments of this application;

[0052] Figure 3 This is a schematic diagram of a third structure of the vehicle energy storage device provided in the embodiments of this application;

[0053] Figure 4 This is a schematic diagram of a fourth structure of the vehicle energy storage device provided in the embodiments of this application;

[0054] Figure 5 This is a fifth structural schematic diagram of the vehicle energy storage device provided in the embodiments of this application;

[0055] Figure 6 This is a sixth structural schematic diagram of the vehicle energy storage device provided in the embodiments of this application;

[0056] Figure 7 A seventh structural schematic diagram of the vehicle energy storage device provided in the embodiments of this application;

[0057] Figure 8 This is an eighth structural schematic diagram of a vehicle energy storage device provided in the embodiments of this application. Detailed Implementation

[0058] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0060] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0061] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The phrase "second connection port" at various locations in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0062] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0063] In the description of the embodiments of this application, the term "multiple frames" refers to two or more (including two).

[0064] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0065] In related technologies, power battery packs composed of sodium-ion, lithium-ion, or hybrid batteries have a wide voltage range, thus requiring high-voltage electrical appliances to be compatible with a wide voltage range. However, at low voltage, there are problems such as insufficient power and insufficient power output of high-voltage electrical appliances.

[0066] This application provides a vehicle energy storage device, see [link to relevant documentation]. Figure 1 As shown, the vehicle energy storage device 600 includes: a power battery pack 100, a voltage conversion circuit 200, and a main control circuit 400; the power battery pack 100 is connected to a first power supply terminal 510 via the voltage conversion circuit 200, which is used to perform voltage conversion between the power battery pack 100 and the first power supply terminal 510; the main control circuit 400 is connected to the voltage conversion circuit 200, and the main control circuit 400 can adjust the working state of the voltage conversion circuit according to the parameters of the first power supply terminal 510 and the power battery pack 100.

[0067] In this embodiment, the power battery pack 100 is connected to the first power supply terminal 510 via a voltage conversion circuit 200. The voltage conversion circuit 200 can perform voltage conversion between the power battery pack 100 and the first power supply terminal 510. The main control circuit 400 is connected to the voltage conversion circuit 200, which has boost and / or buck functions. The parameters of the first power supply terminal 510 and the power battery pack 100 include voltage parameters. The main control circuit 400 can control the working state of the voltage conversion circuit 200 according to the parameters of the first power supply terminal 510 and the power battery pack 100. Thus, when the voltage of the power battery pack 100 is low, or when the DC bus voltage is pulled down due to vehicle acceleration, resulting in a low voltage at the first power supply terminal 510, the voltage conversion circuit 200 maintains the stability of the DC bus voltage, allowing the vehicle to maintain high power.

[0068] In some embodiments, the vehicle energy storage device 600 can be a power battery assembly, which includes a power battery pack 100, a voltage conversion circuit 200, and a main control circuit 400; the main control circuit 400 can be a power control unit, or the main control circuit 400 includes a power control unit.

[0069] By integrating a voltage conversion circuit 200 with buck-boost function into the vehicle energy storage device, the voltage conversion circuit 200 performs voltage conversion between the power battery pack 100 and the first power supply terminal 510. The voltage conversion circuit 200 is controlled by the power control unit, which communicates with the BMS (Battery Management System) or the BMS integrates the power control unit. In some embodiments, the voltage conversion circuit 200 is integrated inside the battery assembly, and the voltage platform of the power battery pack 100 (e.g., the power battery) can be decoupled from the operating voltage of other high-voltage components. When the voltage of the power battery pack 100 is low, or when the vehicle accelerates, the DC bus voltage connected to the first power supply terminal 510 is momentarily pulled down. The power control unit controls the voltage conversion circuit 200 to boost the DC bus voltage to a higher voltage, so that the vehicle maintains high power performance. When the charging pile voltage is too high and the vehicle is fast charging, the voltage conversion circuit 200 can step down to achieve the function of stepping down and boosting current, maximizing the use of the charging pile's charging power to charge the power battery pack 100.

[0070] In some embodiments, see Figure 2 As shown, the power battery pack 100 includes a sodium-ion battery pack 110 and a lithium-ion battery pack 120. The sodium-ion battery pack 110 and the lithium-ion battery pack 120 are respectively connected to a switching circuit 130. The switching circuit 130 is used to control the sodium-ion battery pack 110 and the lithium-ion battery pack 120 to be connected in series or in parallel.

[0071] In this embodiment, the switch circuit 130 controls the sodium-ion battery pack 110 and the lithium-ion battery pack 120 to be connected in series or in parallel. The power battery pack 100, formed by the sodium-ion battery pack 110 and the lithium-ion battery pack 120, or a mixture of the sodium-ion battery pack 110 and the lithium-ion battery pack 120, has a wide voltage range. Therefore, high-voltage electrical appliances are needed to adapt to the wide voltage range. However, at low voltage, the power is insufficient, and there is a problem of insufficient power output from the high-voltage electrical appliances. By integrating a voltage conversion circuit 200 with buck-boost function into the powertrain, not only can the capacitor on the low-voltage side be saved, but also when the output voltage of the power battery pack 100 is low, or when the DC bus voltage is pulled down due to vehicle acceleration, resulting in a low voltage at the first power supply terminal, the voltage conversion circuit can maintain the stability of the DC bus voltage, allowing the vehicle to maintain high power.

[0072] In some embodiments, the main control circuit 400 is further configured to control the voltage conversion circuit 200 to boost the voltage provided by the power battery pack when the voltage of the first power supply terminal 510 is lower than a first preset threshold voltage or the voltage of the power battery pack 100 is lower than a second preset threshold voltage, so that the voltage of the first power supply terminal is kept within the first preset voltage range.

[0073] In this embodiment, one end of the voltage conversion circuit 200 is connected to the power battery pack 100, and the other end is connected to the first power supply terminal 510. When the voltage of the power battery pack 100 or the voltage of the first power supply terminal 510 is low, the voltage conversion circuit 200 can be used to boost the voltage supplied by the power battery pack 100 to maintain the voltage of the first power supply terminal 510 within a first preset voltage range, thus stabilizing the DC bus voltage and allowing the vehicle to maintain high power. For example, one end of the voltage conversion circuit 200 is connected to the power battery pack 100, and the other end is connected to the high-voltage distribution box in the first power supply terminal 510. The high-voltage distribution box supplies power to the connected load based on the voltage output from the power supply side of the voltage conversion circuit 200. When the voltage of the power battery pack 100 or the voltage of the first power supply terminal 510 is low, the input voltage of the high-voltage distribution box is also low. The voltage conversion circuit 200 can be used to boost the voltage supplied by the power battery pack to maintain the voltage of the first power supply terminal within a first preset voltage range, thus stabilizing the DC bus voltage and allowing the vehicle to maintain high power.

[0074] In some embodiments, the main control circuit 400 is further configured to control the voltage conversion circuit 200 to step down the voltage provided by the first power supply terminal 510 when the voltage connected to the first power supply terminal 510 is greater than a third preset threshold voltage, so as to increase the charging current of the voltage conversion circuit 200 to the power battery pack 100.

[0075] In this embodiment of the application, if the voltage connected to the first power supply terminal 510 is too high when the vehicle is charging, the voltage provided by the first power supply terminal can be reduced by the voltage conversion circuit 200 to increase the charging current of the power battery pack, expand the application scenarios of vehicle charging, and maximize the use of the charging power of the charging pile.

[0076] In some embodiments, see Figure 3 As shown, the voltage conversion circuit 200 includes at least one half-bridge 201, the midpoint of the half-bridge of the at least one half-bridge is connected to the positive terminal of the power battery pack, and the negative bus of the at least one half-bridge is connected to the negative terminal of the power battery pack.

[0077] In this embodiment of the application, by setting the midpoint of the half-bridge to be connected to the positive terminal of the power battery pack and the negative busbar of the half-bridge to be connected to the negative terminal of the power battery pack, the voltage between the power battery pack and the first power supply terminal can be converted.

[0078] In some embodiments, see Figure 4 As shown, the voltage conversion circuit 200 also includes a first inductor L1, and at least one half-bridge midpoint is connected to the positive terminal of the power battery pack via the first inductor.

[0079] In this embodiment, by connecting the midpoint of one half-bridge to the positive terminal of the power battery pack via the first inductor, and connecting the negative busbar of the half-bridge to the negative terminal of the power battery pack, the voltage between the power battery pack and the first power supply terminal can be converted. Each arm of the half-bridge can be controlled independently. When a high-voltage electrical appliance experiences a short circuit, the short-circuit current rises more slowly due to the presence of the first inductor. The main control circuit (e.g., the power control unit) can detect the overcurrent and shut down the semiconductor switching elements of the step-up / step-down module within microseconds, cutting off the high-voltage circuit faster than a fuse.

[0080] In some embodiments, see Figure 4 As shown, the half-bridge 201 includes a first switch Q1 and a second switch Q2. The first end of the first switch Q1 and the midpoint of the half-bridge of the second switch Q2 are connected to the positive terminal of the power battery pack 100 via a first inductor L1.

[0081] In some embodiments, see Figure 5 As shown, the voltage conversion circuit 200 includes a first half-bridge 210, a second half-bridge 220, and an energy storage device (first inductor L1). The midpoint of the half-bridges of the first half-bridge 210 and the second half-bridge 220 is connected to the positive terminal of the power battery pack 100 via the energy storage device (first inductor L1). The positive and negative output terminals of the first half-bridge 210 and the second half-bridge 220 are respectively connected to the positive and negative terminals of the first power supply terminal 510.

[0082] In this embodiment, the voltage conversion circuit 200 includes a first half-bridge 210 and a second half-bridge 220. The first end of the energy storage device in the voltage conversion circuit 200 is connected to the midpoint of the first half-bridge 210, and the second end of the energy storage device in the voltage conversion circuit 200 is connected to the midpoint of the second half-bridge 220. By controlling the working states of the main positive switch K21, the first half-bridge 210, and the second half-bridge 220, the power battery pack 100 can charge and store energy in the energy storage device in the voltage conversion circuit 200 through the first half-bridge 210 and the second half-bridge 220. By controlling the working states of the first half-bridge 210 and the second half-bridge 220, the energy storage device in the voltage conversion circuit 200 can charge the power battery pack 100, allowing the energy storage device in the voltage conversion circuit 200 and the power battery pack 100 to charge each other, achieving the purpose of battery self-heating. This helps to eliminate the need for heating film heating or coolant heating in the power battery assembly, making the vehicle energy storage device simpler and facilitating the arrangement and simplification of the internal structure of the vehicle energy storage device.

[0083] In some embodiments, see Figure 5 As shown, the first inductor L1 can be a common-mode inductor. The midpoint of the first half-bridge 210 is connected to the positive terminal of the power battery pack 100 through the first side of the common-mode inductor, and the midpoint of the second half-bridge 220 is connected to the negative terminal of the power battery pack 100 through the second side of the common-mode inductor.

[0084] In this embodiment, the voltage conversion circuit 200 includes a first half-bridge 210, a second half-bridge 220, and a common-mode inductor. The midpoint of the first half-bridge 210 is connected to the positive terminal of the power battery pack 100 via the first side of the common-mode inductor, and the midpoint of the second half-bridge 220 is connected to the negative terminal of the power battery pack 100 via the second side of the common-mode inductor. By controlling the operating states of the main positive switch 21, the first half-bridge 210, and the second half-bridge 220, the power battery pack 100 can charge and store energy in the common-mode inductor via the main positive switch 21, the first half-bridge 210, and the second half-bridge 220. By controlling the operating states of the first half-bridge 210 and the second half-bridge 220, the common-mode inductor charges the power battery pack 100, thereby controlling the power battery pack 100 and the common-mode inductor to charge each other, achieving the purpose of battery self-heating. This helps to eliminate the need for heating film heating or coolant heating in the power battery assembly, making the vehicle energy storage device simpler and facilitating the arrangement and simplification of the internal structure of the vehicle energy storage device.

[0085] In some embodiments, see Figure 5As shown, the first inductor L1 can be a common-mode inductor. The first half-bridge 210 includes a first switch Q1 and a second switch Q2. The second half-bridge 220 includes a third switch Q3 and a fourth switch Q4. The first terminal of the first switch Q1 and the first terminal of the second switch Q2 are connected to the first terminal of the common-mode inductor. The first terminal of the third switch Q3 and the first terminal of the fourth switch Q4 are connected to the second terminal of the common-mode inductor. The second terminal of the first switch Q1 and the second terminal of the third switch Q3 are connected to the positive terminal of the first power supply terminal 510. The second terminal of the second switch Q2 and the second terminal of the fourth switch Q4 are connected to the negative terminal of the first power supply terminal 510. The third and fourth terminals of the common-mode inductor are connected to the positive terminal of the power battery pack 100.

[0086] In this embodiment, by controlling the working states of the main positive switch 21, the first half-bridge 210, and the second half-bridge 220, the power battery pack 100 can charge and store energy through the common-mode inductor via the main positive switch 21, the first half-bridge 210, and the second half-bridge 220. By controlling the working states of the first half-bridge 210 and the second half-bridge 220, the common-mode inductor charges the power battery pack 100, thereby controlling the power battery pack 100 and the common-mode inductor to charge each other, achieving the purpose of battery self-heating. This helps to eliminate the heating film heating or coolant heating in the power battery assembly, making the vehicle energy storage device simpler and facilitating the arrangement and simplification of the internal structure of the vehicle energy storage device.

[0087] In some embodiments, see Figure 5 As shown, the vehicle energy storage device also includes a main positive switch K21 and a main negative switch K22. The positive terminal of the power battery pack 100 is connected to the voltage conversion circuit 200 via the main positive switch K21, and the negative terminal of the power battery pack 100 is connected to the voltage conversion circuit 200 via the main negative switch K22.

[0088] In this embodiment of the application, the positive terminal of the power battery pack 100 is connected to the positive bus of the voltage conversion circuit 200 via the main positive switch K21, and the negative terminal of the power battery pack 100 is connected to the negative bus of the voltage conversion circuit 200 via the main negative switch K22. The charging and discharging processes of the power battery pack 100 can be controlled by the main positive switch K21 and the main negative switch K22.

[0089] In some embodiments, see Figure 6 As shown, the main positive switch K21 includes power semiconductor devices, can reuse the voltage conversion circuit 200, optimize the high voltage architecture, realize the rapid disconnection of the high voltage circuit in case of an emergency, eliminate the need for pre-charge relays and pre-charge resistors, and quickly realize active discharge, thereby reducing the overall vehicle cost.

[0090] In some embodiments, see Figure 6 As shown, the main positive switch K21 also includes a diode, which is connected in reverse parallel with the power semiconductor device.

[0091] In this embodiment of the application, when the vehicle is involved in a collision, the power semiconductor device can be quickly turned off and the buck-boost output of the voltage conversion circuit 200 can be quickly stopped. Then the voltage conversion circuit 200 enters the active discharge mode and feeds the energy on the output side back to the power battery pack 100 through the diode connected in reverse parallel to the power semiconductor device, so as to quickly complete the active discharge.

[0092] In some embodiments, see Figure 7 As shown, the main negative switch K22 includes a power semiconductor device.

[0093] In the embodiments of this application, see Figure 7 As shown, the main negative switch K22 includes power semiconductor devices, can reuse the voltage conversion circuit 200, optimize the high voltage architecture, realize the rapid disconnection of the high voltage circuit in case of an emergency, eliminate the need for pre-charge relays and pre-charge resistors, and quickly realize active discharge, thereby reducing the overall vehicle cost.

[0094] In some embodiments, see Figure 7 As shown, the main negative switch K22 also includes a diode, which is connected in reverse parallel with the power semiconductor device.

[0095] In this embodiment of the application, when the vehicle is involved in a collision, the power semiconductor device can be quickly turned off and the buck-boost output of the voltage conversion circuit 200 can be quickly stopped. Then the voltage conversion circuit 200 enters the active discharge mode and feeds the energy on the output side back to the power battery pack 100 through the diode connected in reverse parallel to the power semiconductor device, so as to quickly complete the active discharge.

[0096] In some embodiments, see Figure 8 As shown, the vehicle energy storage device 600 also includes: a fast charging positive switch K31, a fast charging negative switch K32, and a second power supply terminal 520. The positive terminal of the second power supply terminal 520 is connected to the positive bus of the voltage conversion circuit 200 via the fast charging positive switch K31, and the negative terminal of the second power supply terminal 520 is connected to the negative bus of the voltage conversion circuit 200 via the fast charging negative switch K32.

[0097] In this embodiment, the fast charging positive switch K31 is connected to the positive terminal CH+ of the second power supply terminal 520, and the fast charging negative switch K32 is connected to the negative terminal CH- of the second power supply terminal 520. The second power supply terminal 520 can be connected to a fast charging pile, which can then supply high-voltage electricity. The voltage conversion circuit 200 performs voltage reduction and current boosting on the supplied high-voltage electricity, which can fully utilize the charging capacity of the charging pile and expand the charging voltage range of the vehicle energy storage device.

[0098] In some embodiments, see Figure 8As shown, the vehicle energy storage device 600 also includes a first current-limiting resistor R1 and a fifth switching transistor Q5, which are connected in series between the positive and negative terminals on the battery side of the voltage conversion circuit 200.

[0099] In this embodiment, by connecting a first current-limiting resistor R1 and a fifth switch Q5 in series between the positive and negative terminals on the battery side of the voltage conversion circuit 200, when the vehicle energy storage device needs to actively discharge, the energy of the filter capacitor C1 can form a freewheeling circuit through the half-bridge, energy storage device, first current-limiting resistor R1 and fifth switch Q5 in the voltage conversion circuit 200. Then, the fifth switch Q5 is turned off, and the energy storage device charges the power battery pack 100, thus completing one active discharge cycle and quickly completing the energy dissipation process of the filter capacitor C1.

[0100] In some embodiments, see Figure 8 As shown, the vehicle energy storage device 600 also includes an auxiliary power supply 700, which is connected between the positive and negative terminals on the battery side of the voltage conversion circuit 200.

[0101] In this embodiment, by connecting an auxiliary power supply 700 between the positive and negative terminals of the battery side of the voltage conversion circuit 200, the auxiliary power supply 700 can provide the required electrical energy to the first power supply terminal 510 via the voltage conversion circuit 200 in the event of an abnormality in the power battery pack 100, thereby improving the power supply stability of the first power supply terminal 510 and reducing the safety hazards caused by the abnormality of the power battery pack 100.

[0102] In some embodiments, see Figure 8 As shown, the vehicle energy storage device 600 also includes: a first current sensor CT1, which is connected in series with the power battery pack 100. The first current sensor CT1 is used to detect the current flowing through the power battery pack 100 and send the detection result to the main control circuit 400. The main control circuit 400 adjusts the switching state of each switch in the voltage conversion circuit 200 according to the detection result.

[0103] In some embodiments, see Figure 8 As shown, the vehicle energy storage device 600 also includes a second current sensor CT2 and a third current sensor CT3. The second current sensor CT2 is used to detect the current flowing through the first half-bridge 210 and send the detection result to the main control circuit 400. The third current sensor CT3 is used to detect the current flowing through the second half-bridge 220 and send the detection result to the main control circuit 400. The main control circuit 400 adjusts the switching state of each switching transistor in the voltage conversion circuit 200 according to the detection result.

[0104] In some embodiments, see Figure 8As shown, the vehicle energy storage device 600 is also equipped with a temperature sensor, which is used to detect the temperature inside the vehicle energy storage device 600. The main control circuit 400 can also acquire the temperature detection signal sampled by the temperature sensor and control the switching state of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 according to the temperature detection signal. There can be multiple temperature sensors to detect the temperature at multiple locations in the vehicle energy storage device 600. For example, when the temperature of one or more of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 is higher than a preset temperature threshold, the main control circuit 400 can effectively reduce the temperature of the switch by controlling the duty cycle of the corresponding switch to decrease or by controlling the switch to turn off, thereby reducing the safety hazards of the vehicle energy storage device 600.

[0105] In some embodiments, see Figure 8 As shown, the vehicle energy storage device 600 also includes a filter capacitor C1, the two ends of which are respectively connected between the positive and negative busbars of the power supply side of the voltage conversion circuit 200.

[0106] In this embodiment, by setting the two ends of the filter capacitor C1 to be connected between the positive and negative buses of the power supply side of the voltage conversion circuit 200, the positive bus of the power supply side of the voltage conversion circuit 200 is connected to the positive terminal HV+ of the first power supply terminal, and the negative bus of the power supply side of the voltage conversion circuit 200 is connected to the negative terminal HV- of the first power supply terminal. The voltage of the first power supply terminal 510 can be filtered by the filter capacitor C1, and the voltage input to the first power supply terminal 510 can be buffered, reducing the voltage fluctuation of the first power supply terminal 510 and improving the power supply stability of the first power supply terminal 510.

[0107] In some embodiments, the main control circuit 400 is further configured to control the switching duty cycle of the power semiconductor device to gradually increase in the precharge mode until the power semiconductor device is fully turned on.

[0108] In this embodiment, when the main control circuit 400 receives the high-voltage power-on command, it first operates in pre-charge mode. It first closes the main positive switch K21 and the main negative switch K22. At least one of the main positive switch K21 and the main negative switch K22 is a power semiconductor device. By controlling the duty cycle of the power semiconductor device to be adjusted from the minimum to a duty cycle of 1, the voltage conversion circuit 200 is started until the high-voltage bus of the first power supply terminal 510 reaches the target voltage, thereby sending a ready state to the battery management unit. The vehicle controller sends a power battery ready to continue, completing the power supply pre-charge process.

[0109] In some embodiments, the main control circuit 400 includes a battery management unit (BMU) and a power control unit. The power control unit can control the voltage conversion circuit 200 and the auxiliary power supply 700. After receiving the high-voltage power-on command, the BMU determines that the main negative switch K22 is normal, closes the main negative switch K22, and sends a closed state to the power control unit. The power control unit controls the duty cycle of the main positive switch K21 to be adjusted from the minimum to a duty cycle of 1. The power control unit starts the voltage conversion circuit 200 until the positive terminal HV+ of the first power supply terminal 510 reaches the target voltage, and then sends a ready-to-go state to the BMU. The BMU sends a power battery ready-to-go state to the vehicle controller, and the vehicle controller sends a start command to each high-voltage electrical device.

[0110] In some embodiments, the main control circuit 400 includes a BMU, which may integrate a power control unit, thus eliminating the need for interaction between the BMU and the power control unit.

[0111] In some embodiments, the main control circuit 400 is further configured to control the first switch Q1 and the third switch Q3 to be turned on and the second switch Q2 and the fourth switch Q4 to be turned off in the through mode.

[0112] In this embodiment, if the voltage of the power battery pack 100 is consistent with the required voltage of the first power supply terminal 510, the power battery pack 100 can directly supply power to high-voltage electrical appliances by controlling the first switch Q1 and the third switch Q3 to be turned on and the second switch Q2 and the fourth switch Q4 to be turned off. During charging and braking energy recovery, the energy enters the battery directly without going through the step-up and step-down voltage, which can reduce the energy loss caused by the voltage conversion circuit 200.

[0113] In some embodiments, the main control circuit 400 is further configured to control the voltage conversion circuit 200 to step down the voltage provided by the first power supply terminal 510 in DC step-down charging mode, so as to increase the charging current of the voltage conversion circuit 200 to the power battery pack 100.

[0114] In this embodiment of the application, under charging conditions, if the voltage provided by the charging pile is high and the voltage connected to the first power supply terminal 510 is greater than the preset charging threshold voltage, the voltage conversion circuit 200 is controlled to step down the voltage provided by the first power supply terminal 510 in order to increase the charging current of the voltage conversion circuit 200 to the power battery pack 100. In this way, the charging power of the charging pile is utilized to the maximum extent by stepping down the voltage and increasing the current.

[0115] In some embodiments, the main control circuit 400 is also used to control the power semiconductor device to turn off in active discharge mode so that the energy of the energy storage device in the voltage conversion circuit 200 is fed back to the power battery pack 100 via a diode.

[0116] In this embodiment, when the vehicle energy storage device needs to discharge quickly, the main control circuit 400 operates in active discharge mode. The power semiconductor device can be quickly turned off and the buck-boost output of the voltage conversion circuit 200 can be quickly stopped. Then, the voltage conversion circuit 200 enters active discharge mode and feeds the energy on the output side back to the power battery pack 100 through the diode connected in reverse parallel to the power semiconductor device, thus quickly completing the active discharge.

[0117] In some embodiments, the main control circuit 400 is also used to control the main positive switch K21 to turn off in the power-down mode, and control the voltage conversion circuit 200 to operate in the active discharge mode until the voltage of the first power supply terminal 510 is lower than the power-down safety threshold voltage, and then control the main negative switch K22 to turn off.

[0118] In this embodiment, after the power battery pack 100 completes the pre-charging process, and the voltage conversion circuit 200 operates in direct mode or boost mode, the voltage conversion circuit 200 can be controlled to operate in direct mode first, and then the voltage conversion circuit 200 can be controlled to enter active discharge mode, so that the energy on the output side is fed back to the power battery pack 100 through the diode connected in reverse parallel to the power semiconductor device, until the voltage of the first power supply terminal 510 is lower than the power-down safety threshold voltage, and the main negative switch K22 is controlled to turn off.

[0119] In some embodiments, the main control circuit 400 is further configured to control the voltage conversion circuit 200 to boost the voltage supplied by the power battery pack 100 in boost mode, so that the voltage of the first power supply terminal 510 is maintained within a first preset voltage range.

[0120] In this embodiment, if the load power connected to the first power supply terminal 510 suddenly increases, the voltage of the first power supply terminal 510 may be lower than the first preset threshold voltage. Alternatively, if the voltage of the power battery pack 100 is lower than the second preset threshold voltage, the voltage of the first power supply terminal 510 may also be lower than the first preset threshold voltage. In this case, the voltage provided by the power battery pack 100 can be boosted by the voltage conversion circuit 200 to keep the voltage of the first power supply terminal 510 within the first preset voltage range, thereby maintaining the output voltage of the vehicle energy storage device within the first preset voltage range, improving the power supply stability of the vehicle energy storage device, and enabling the vehicle to maintain high power performance.

[0121] In some embodiments, the main control circuit 400 is also used to control the switching state of the voltage conversion circuit 200 in the regenerative braking mode, so that the reverse current generated by the energy storage device in the voltage conversion circuit 200 charges the power battery pack 100, and adjusts the switching duty cycle of the voltage conversion circuit 200 so that the voltage of the first power supply terminal 510 is maintained within the first preset voltage range.

[0122] In this embodiment, when the vehicle is driving normally, the voltage conversion circuit 200 operates in boost mode, and the voltage of the first power supply terminal 510 is maintained within the first preset voltage range. During braking, the induced electromotive force fed back by the electric drive assembly exceeds the first preset voltage range, causing the current in the inductor to flow in the reverse direction. The main control circuit 400 detects the reverse current direction and adjusts the duty cycle to maintain the DC bus voltage within the first preset voltage range. When the induced voltage fed back by the electric drive is low, the DC bus voltage is lower than the lower limit of the first preset voltage range. The main control circuit 400 then adjusts the duty cycle of the switching transistor in the voltage conversion circuit 200 again to maintain the DC bus voltage within the first preset voltage range.

[0123] In some embodiments, the main control circuit 400 is also used to control the sodium-ion battery pack 110 or the lithium-ion battery pack 120 to supply power to the first power supply terminal 510 after being boosted by the voltage conversion circuit 200 in a redundant power supply mode.

[0124] This application also provides a vehicle, which includes a vehicle energy storage device as described in any of the above embodiments.

[0125] In this embodiment, the power battery pack 100 is connected to the first power supply terminal 510 via a voltage conversion circuit 200. The voltage conversion circuit 200 can perform voltage conversion between the power battery pack 100 and the first power supply terminal 510. The main control circuit 400 is connected to the voltage conversion circuit 200, which has boost and / or buck functions. The parameters of the first power supply terminal 510 and the power battery pack 100 include voltage parameters. The main control circuit 400 can control the working state of the voltage conversion circuit 200 according to the parameters of the first power supply terminal 510 and the power battery pack 100. Thus, when the voltage of the power battery pack 100 is low, or when the DC bus voltage is pulled down due to vehicle acceleration, resulting in a low voltage at the first power supply terminal 510, the voltage conversion circuit 200 maintains the stability of the DC bus voltage, allowing the vehicle to maintain high power.

[0126] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0127] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0128] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the electronic device embodiments described above are merely illustrative. For example, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0129] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0130] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0131] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A vehicle energy storage device, characterized by, The vehicle energy storage device includes: a power battery pack, a voltage conversion circuit, and a main control circuit; The power battery pack is connected to the first power supply terminal via the voltage conversion circuit; The main control circuit is connected to the voltage conversion circuit and is used to adjust the working state of the voltage conversion circuit according to the parameters of the first power supply terminal and the power battery pack.

2. The vehicle energy storage device of claim 1, wherein, The power battery pack includes a sodium-ion battery pack, a lithium-ion battery pack, and a switching circuit. The sodium-ion battery pack and the lithium-ion battery pack are respectively connected to the switching circuit, which is used to control the sodium-ion battery pack and the lithium-ion battery pack to be connected in series or in parallel.

3. The vehicle energy storage device of claim 1, wherein, The main control circuit is also used to control the voltage conversion circuit to boost the voltage provided by the power battery pack when the voltage at the first power supply terminal is lower than the first preset threshold voltage or the voltage of the power battery pack is lower than the second preset threshold voltage, so as to keep the voltage at the first power supply terminal within the first preset voltage range.

4. The vehicle energy storage device of claim 1, wherein, The main control circuit is also used to control the voltage conversion circuit to step down the voltage provided by the first power supply terminal when the voltage connected to the first power supply terminal is greater than the third preset threshold voltage, so as to increase the charging current of the power battery pack by the voltage conversion circuit.

5. The vehicle energy storage device of claim 1, wherein, The voltage conversion circuit includes at least one half-bridge, the midpoint of at least one half-bridge is connected to the positive terminal of the power battery pack, and the negative busbar of at least one half-bridge is connected to the negative terminal of the power battery pack.

6. The vehicle energy storage device of claim 5, wherein, The voltage conversion circuit further includes a first inductor, and at least one half-bridge midpoint is connected to the positive terminal of the power battery pack via the first inductor.

7. The vehicle energy storage device of claim 1, wherein, The voltage conversion circuit includes: a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, and a common-mode inductor; The first terminal of the first switch and the first terminal of the second switch are both connected to the first terminal of the common-mode inductor. The first terminal of the third switch and the first terminal of the fourth switch are both connected to the second terminal of the common-mode inductor. The second terminal of the first switch and the second terminal of the third switch are both connected to the positive terminal of the first power supply terminal. The second terminal of the second switch and the second terminal of the fourth switch are both connected to the negative terminal of the first power supply terminal. The third and fourth terminals of the common-mode inductor are both connected to the positive terminal of the power battery pack.

8. The vehicle energy storage device of any of claims 1-7, wherein, The vehicle energy storage device further includes a main positive switch and a main negative switch. The positive terminal of the power battery pack is connected to the voltage conversion circuit via the main positive switch, and the negative terminal of the power battery pack is connected to the voltage conversion circuit via the main negative switch.

9. The vehicle energy storage device of claim 8, wherein, The main positive switch and / or the main negative switch include power semiconductor devices.

10. The vehicle energy storage device of claim 9, wherein, The main positive switch and / or the main negative switch further include a diode; The diode is connected in reverse parallel with the power semiconductor device.

11. The vehicle energy storage device of any of claims 1-7, wherein, The vehicle energy storage device further includes: a fast charging positive switch, a fast charging negative switch, and a second power supply terminal. The positive terminal of the second power supply terminal is connected to the positive bus of the voltage conversion circuit via the fast charging positive switch, and the negative terminal of the second power supply terminal is connected to the negative bus of the voltage conversion circuit via the fast charging negative switch.

12. The vehicle energy storage device of any of claims 1-7, wherein, The vehicle energy storage device further includes a filter capacitor, the two ends of which are respectively connected between the positive and negative busbars of the power supply side of the voltage conversion circuit.

13. The vehicle energy storage device of any of claims 1-7, wherein, The vehicle energy storage device further includes a first current-limiting resistor and a fifth switching transistor, wherein the first current-limiting resistor and the fifth switching transistor are connected in series between the positive and negative terminals on the battery side of the voltage conversion circuit.

14. The vehicle energy storage device of any of claims 1-7, wherein, The vehicle energy storage device further includes an auxiliary power supply, which is connected between the positive and negative terminals on the battery side of the voltage conversion circuit.

15. The vehicle energy storage device of claim 10, wherein, The main control circuit is also used to control the switching duty cycle of the power semiconductor device to gradually increase in the pre-charge mode until the power semiconductor device is fully turned on.

16. The vehicle energy storage device of claim 10, wherein, The main control circuit is also used to control the power semiconductor device to turn off in active discharge mode, so that the energy of the energy storage device in the voltage conversion circuit is fed back to the power battery pack through the diode.

17. The vehicle energy storage device of claim 7, wherein, The main control circuit is also used to control the first and third switching transistors to be turned on and the second and fourth switching transistors to be turned off in the direct-through mode.

18. The vehicle energy storage device of claim 10, wherein, The main control circuit is also used to control the main positive switch to turn off in the power-down mode, and to control the voltage conversion circuit to operate in active discharge mode until the voltage at the first power supply terminal is lower than the fourth preset threshold voltage, and then control the main negative switch to turn off.

19. The vehicle energy storage device of claim 6, wherein, The main control circuit is also used to control the switching state of the voltage conversion circuit in the regenerative braking mode, so that the current of the first inductor is reversed to charge the power battery pack, and to adjust the switching duty cycle of the voltage conversion circuit so that the voltage of the first power supply terminal is kept within a first preset voltage range.

20. A vehicle characterized by The vehicle includes: a vehicle energy storage device as described in any one of claims 1 to 19.

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