Bidirectional charging circuit and direct-current charging pile

Abstract

Provided in the present disclosure are a bidirectional charging circuit and a direct-current charging pile. The bidirectional charging circuit comprises a plurality of bidirectional voltage conversion circuits, which are connected in parallel, and a charging pile controller, wherein first ends of the plurality of bidirectional charging circuits are all connected to an external device, and second ends of the plurality of bidirectional charging circuits are all connected to a battery pack of a direct-current charging pile; the external device is a direct-current power source or a charging device; a signal collection end of the charging pile controller is connected to a first signal output end of the external device and a second signal output end of the battery pack; and a control signal output end of the charging pile controller is connected to control signal input ends of the plurality of bidirectional voltage conversion circuits. On this basis, during charging and discharging of the battery pack, the method of a plurality of bidirectional voltage conversion circuits being connected in parallel is used to increase the load-carrying capacity of a charging pile and increase the charging current, thereby increasing the charging efficiency.

Description

A bidirectional charging circuit and a DC charging pile

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202311515694.8, filed with the State Intellectual Property Office of China on November 14, 2023, entitled “A Bidirectional Charging Circuit and DC Charging Pile,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of charging piles, and in particular to a bidirectional charging circuit and a DC charging pile. Background Art

[0004] With the development of new energy technologies, electric vehicles are becoming increasingly common, significantly improving the range of existing new energy vehicles. Furthermore, to support the development of new energy vehicles, charging stations have been built and charging piles have been installed in service areas. However, the charging requirements of new energy vehicles are complex. For example, the number of vehicles on highways surges during holidays, resulting in an insufficient number of fixed charging piles. Alternatively, charging may be required during travel. Therefore, there is an urgent need for mobile charging piles that can flexibly meet charging needs. Existing fixed charging piles typically have only one DC-DC converter circuit. When the output current is high, their efficiency is low, heat is generated, and output ripple is high, requiring a high saturation current for the inductor. Mobile charging piles, on the other hand, require high current charging to improve charging efficiency and address various emergencies associated with new energy vehicles.

[0005] Summary of the Invention

[0006] In view of this, the purpose of the present disclosure is to provide a bidirectional charging circuit and a DC charging pile, which can adjust the discharge current according to the load weight and improve the charging efficiency.

[0007] An embodiment of the present disclosure provides a bidirectional charging circuit, the circuit comprising: a plurality of bidirectional voltage conversion circuits and a charging pile controller connected in parallel;

[0008] The first ends of the plurality of bidirectional voltage conversion circuits are all connected to an external device, and the second ends of the plurality of bidirectional voltage conversion circuits are all connected to a battery pack of a DC charging pile; wherein the external device is a DC power supply or a charging device;

[0009] The signal acquisition end of the charging pile controller is connected to the first signal output end of the external device and the second signal output end of the battery pack, and the control signal output end of the charging pile controller is connected to the control signal input ends of the multiple bidirectional voltage conversion circuits.

[0010] In some embodiments, in the bidirectional charging circuit, the charging pile controller is used to:

[0011] The number of bidirectional voltage conversion circuits to be used is determined according to the charging power of the external device and the charging power of the battery pack.

[0012] In some embodiments, in the bidirectional charging circuit, the bidirectional voltage conversion circuit includes: a first-stage bidirectional voltage conversion circuit and a second-stage bidirectional voltage conversion circuit;

[0013] The first end of the first-level bidirectional voltage conversion circuit is connected to an external device, the second end of the first-level bidirectional voltage conversion circuit is connected to the first end of the second-level bidirectional voltage conversion circuit, and the second end of the second-level bidirectional voltage conversion circuit is connected to the battery pack of the DC charging pile.

[0014] In some embodiments, in the bidirectional charging circuit, the charging pile controller is further configured to:

[0015] Based on the collected first voltage signal of the external device, the second voltage signal of the battery pack, and the intermediate voltage signal between the first-stage bidirectional voltage conversion circuit and the second-stage bidirectional voltage conversion circuit, the voltage conversion multiples of the first-stage bidirectional voltage conversion circuit and the second-stage bidirectional voltage conversion circuit are controlled.

[0016] In some embodiments, in the bidirectional charging circuit, the first-stage bidirectional voltage conversion circuit is a synchronous rectification circuit, and the second-stage bidirectional voltage conversion circuit is a bidirectional BUCK / BOOST circuit.

[0017] In some embodiments, in the bidirectional charging circuit, the charging pile controller is further configured to:

[0018] When the charging pile controller controls N bidirectional voltage conversion circuits to work in parallel, the number N of bidirectional voltage conversion circuits working in parallel is sent to the bidirectional voltage conversion circuit;

[0019] The bidirectional voltage conversion circuit is configured to determine a phase shift angle of the bidirectional voltage conversion circuit based on the number N, and adjust a phase of an output current of the bidirectional voltage conversion circuit based on the phase shift angle.

[0020] In some embodiments, in the bidirectional charging circuit, determining the phase shift angle of the bidirectional voltage conversion circuit based on the number N includes:

[0021] Determining a phase shift angle of a bidirectional BUCK / BOOST circuit in the bidirectional voltage conversion circuit based on the number N;

[0022] When the synchronous rectification circuit in the bidirectional voltage conversion circuit includes a resonant circuit and the synchronous rectification circuit operates at a resonant frequency, the phase shift angle of the synchronous rectification circuit in the bidirectional voltage conversion circuit is determined based on the number N.

[0023] In some embodiments, in the bidirectional charging circuit, the synchronous rectification circuit includes a resonant circuit, so that the synchronous rectification circuit operates in a resonant mode.

[0024] In some embodiments, in the bidirectional charging circuit, the charging pile controller is further configured to:

[0025] According to the first voltage signal of the external device and the second voltage signal of the battery pack, as well as the charging stage, it is determined whether the synchronous rectification circuit enters the phase-shift DAB mode or the resonant mode.

[0026] In some embodiments, in the bidirectional charging circuit, the synchronous rectification circuit includes a first full-bridge circuit, a transformer circuit, and a second full-bridge circuit connected in series;

[0027] The four switches in the first full-bridge circuit are respectively connected to the charging pile controller, and the four switches in the second full-bridge circuit are respectively connected to the charging pile controller;

[0028] A first end of the first full-bridge circuit is connected to an external device, and a second end of the second full-bridge circuit is connected to a bidirectional BUCK / BOOST circuit.

[0029] In some embodiments, in the bidirectional charging circuit, the transformer circuit includes a first transformer-side circuit and a second transformer-side circuit;

[0030] The first transformer side circuit comprises a first resonant capacitor, a first resonant inductor and a first transformer coil connected in series in sequence;

[0031] The second transformer-side circuit includes a second resonant capacitor, a second resonant inductor, and a second transformer coil connected in series.

[0032] In some embodiments, in the bidirectional charging circuit, the transformer circuit includes two resonant current collection units, and the first transformer-side circuit and the second transformer-side circuit are each connected in series with a resonant current collection unit;

[0033] The two resonant current acquisition units are electrically connected to the charging pile controller respectively.

[0034] In some embodiments, in the bidirectional charging circuit, the bidirectional BUCK / BOOST circuit includes: an intermediate-side boost-buck switching circuit, a boost-buck inductor, a battery-side boost-buck switching circuit, and a boost-buck capacitor;

[0035] The intermediate side boost-buck switch switching circuit is connected to the second end of the synchronous rectification circuit, and the cutout of the intermediate side boost-buck switch switching circuit is connected to the cutout of the battery side boost-buck switch switching circuit through the boost-buck inductor; the battery side boost-buck switch switching circuit is connected in parallel with the boost-buck capacitor, and the boost-buck capacitor is connected in parallel at both ends of the battery pack.

[0036] In some embodiments, in the bidirectional charging circuit, the intermediate-side boost-buck switching circuit and the battery-side boost-buck switching circuit in the bidirectional BUCK / BOOST circuit are both electrically connected to a charging pile controller to implement switching between multiple operating modes under the control of the charging pile controller.

[0037] The multiple operating modes include: a BUCK mode when charging the battery pack, a BOOST mode when charging the battery pack; a BUCK mode when discharging the battery pack, and a BOOST mode when discharging the battery pack.

[0038] In some embodiments, in the bidirectional charging circuit, the intermediate-side boost-buck switching circuit includes two boost-buck switches connected in series, with the cutout being between the two boost-buck switches;

[0039] The battery side boost-buck switch switching circuit includes two boost-buck switches connected in series, and the cutout is between the two boost-buck switches.

[0040] In some embodiments, a DC charging pile is further provided, comprising a charging pile body, a battery pack and the bidirectional charging circuit;

[0041] The bidirectional charging circuit and battery pack are both located inside the charging pile body.

[0042] In some embodiments, in the DC charging pile, the battery pack includes a plurality of sub-battery modules connected in series and a plurality of heat dissipation layers;

[0043] At least two sub-battery modules are placed side by side on each heat dissipation layer plate, a first air duct is reserved between the sub-battery modules placed side by side, and a second air duct is reserved between the heat dissipation layers.

[0044] In some embodiments, in the DC charging pile, heat dissipation fins are provided on the heat dissipation layer plate.

[0045] In some embodiments, in the DC charging pile, the charging pile includes a first heat dissipation mechanism; the first heat dissipation mechanism includes a liquid cooler and a fan;

[0046] The air outlet of the fan faces the inlet of the second air duct, and the heat exchange plate of the liquid cooler is located between the air outlet of the fan and the inlet of the second air duct, so as to blow the cold air at the heat exchange plate of the liquid cooler into the second air duct.

[0047] In some embodiments, in the DC charging pile, the fan is connected to the fan control terminal of the charging pile controller, so that the charging pile controller controls the fan speed according to the charging current.

[0048] In some embodiments, the DC charging pile further includes a second heat dissipation mechanism, which includes a liquid cooling layer plate, a refrigerator, and a radiator;

[0049] Each voltage conversion circuit in the bidirectional charging circuit is placed on a liquid cooling plate; the refrigerator delivers cooling liquid through the liquid cooling plate to dissipate heat for each voltage conversion circuit, the liquid cooling plate returns water to the refrigerator, the refrigerator then delivers cooling liquid to the radiator, and the radiator returns water to the refrigerator.

[0050] In some embodiments, the DC charging pile further comprises a communication module, and the communication module is communicatively connected to the charging pile controller;

[0051] The communication module is used to receive a charging signal generated based on a user operation and send the charging signal to a charging pile controller, so that the charging pile controller charges the external device based on the charging signal.

[0052] In some embodiments, in the DC charging pile, the charging pile further includes a fixing member and a power connector;

[0053] The battery pack is detachably mounted in the charging pile body via the fixing member, and the positive and negative electrodes of the battery pack are plug-in connected to the positive and negative electrode interfaces of the charging pile body via a power connector.

[0054] In some embodiments, in the DC charging pile, a plurality of temperature probes are provided in the battery pack to collect a plurality of temperature data in the battery pack and send the temperature data to the charging pile controller.

[0055] An embodiment of the present disclosure provides a bidirectional charging circuit and a DC charging pile, wherein the bidirectional charging circuit includes multiple parallel bidirectional voltage conversion circuits and a charging pile controller; the first ends of the multiple bidirectional voltage conversion circuits are all connected to an external device, and the second ends of the multiple bidirectional voltage conversion circuits are all connected to a battery pack of the DC charging pile; wherein the external device is a DC power supply or a charging device; the signal acquisition end of the charging pile controller is connected to the first signal output end of the external device and the second signal output end of the battery pack, and the control signal output end of the charging pile controller is connected to the control signal input end of the multiple bidirectional voltage conversion circuits. Based on this, when charging a new energy vehicle or a DC charging pile, multiple bidirectional voltage conversion circuits are connected in parallel to improve the load capacity of the charging pile, increase the charging current, and thus improve the charging efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0057] FIG1 shows a circuit schematic diagram of a bidirectional charging circuit according to an embodiment of the present disclosure;

[0058] FIG2 shows a circuit schematic diagram of a bidirectional voltage conversion circuit according to an embodiment of the present disclosure;

[0059] FIG3 shows a circuit diagram of a synchronous rectification circuit according to an embodiment of the present disclosure;

[0060] FIG4 shows a circuit diagram of a bidirectional BUCK / BOOST circuit according to an embodiment of the present disclosure;

[0061] FIG5 shows a schematic diagram of the phase shift control process according to an embodiment of the present disclosure;

[0062] FIG6 shows a schematic diagram of phase-shifted waveforms of a bidirectional BUCK / BOOST circuit according to an embodiment of the present disclosure;

[0063] FIG7 shows a schematic diagram of a phase-shift waveform of a CLLLC unit according to an embodiment of the present disclosure;

[0064] FIG8 shows a schematic structural diagram of the first heat dissipation mechanism according to an embodiment of the present disclosure;

[0065] FIG9 shows a schematic structural diagram of the second heat dissipation mechanism according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. It should be understood that the drawings in the present disclosure are only for the purpose of illustration and description and are not used to limit the scope of protection of the present disclosure. In addition, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in the present disclosure illustrate operations implemented according to some embodiments of the present disclosure. It should be understood that the operations of the flowchart can be implemented out of sequence, and steps that do not have a logical context relationship can be reversed in order or implemented simultaneously. In addition, those skilled in the art, guided by the contents of the present disclosure, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0067] In addition, the described embodiments are only a portion of the embodiments of the present disclosure, rather than all of the embodiments. The components of the embodiments of the present disclosure generally described and shown in the drawings herein can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the disclosure claimed for protection, but merely represents selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present disclosure.

[0068] It should be noted that the term “comprising” will be used in the embodiments of the present disclosure to indicate the existence of the features claimed thereafter, but does not exclude the addition of other features.

[0069] With the development of new energy technologies, electric vehicles are becoming increasingly common, significantly improving the range of existing new energy vehicles. Furthermore, to support the development of new energy vehicles, charging stations have been built and charging piles have been installed in service areas. However, the charging requirements of new energy vehicles are complex. For example, the number of vehicles on highways surges during holidays, resulting in an insufficient number of fixed charging piles. Alternatively, charging may be required during travel. Therefore, there is an urgent need for mobile charging piles that can flexibly meet charging needs. Existing fixed charging piles typically have only one DC-DC converter circuit. When the output current is high, their efficiency is low, heat is generated, and output ripple is high, requiring a high saturation current for the inductor. Mobile charging piles, on the other hand, require high current charging to improve charging efficiency and address various emergencies associated with new energy vehicles.

[0070] Based on this, an embodiment of the present disclosure provides a bidirectional charging circuit and a DC charging pile, wherein the bidirectional charging circuit includes multiple parallel bidirectional voltage conversion circuits and a charging pile controller; the first ends of the multiple bidirectional voltage conversion circuits are all connected to an external device, and the second ends of the multiple bidirectional voltage conversion circuits are all connected to the battery pack of the DC charging pile; wherein, the external device is a DC power supply or a charging device; the signal acquisition end of the charging pile controller is connected to the first signal output end of the external device and the second signal output end of the battery pack, and the control signal output end of the charging pile controller is connected to the control signal input end of the multiple bidirectional voltage conversion circuits. Based on this, when charging a new energy vehicle or charging a DC charging pile, multiple bidirectional voltage conversion circuits are connected in parallel to improve the load capacity of the charging pile, increase the charging current, and thus improve the charging efficiency.

[0071] Please refer to FIG1 , which shows a circuit schematic diagram of a bidirectional charging circuit according to an embodiment of the present disclosure. The bidirectional charging circuit includes: a plurality of bidirectional voltage conversion circuits 102 connected in parallel and a charging pile controller 101;

[0072] The first ends of the plurality of bidirectional voltage conversion circuits 102 are all connected to an external device 104, and the second ends of the plurality of bidirectional voltage conversion circuits 102 are all connected to a battery pack 103 of a DC charging pile; wherein the external device 104 is a DC power supply or a charging device;

[0073] The signal acquisition end of the charging pile controller 101 is connected to the first signal output end of the external device 104 and the second signal output end of the battery pack 103 , and the control signal output end of the charging pile controller 101 is connected to the control signal input end of the multiple bidirectional voltage conversion circuits 102 .

[0074] In an embodiment of the present disclosure, the bidirectional charging circuit is arranged in a mobile charging pile, and an external power supply charges the charging pile through the bidirectional charging circuit, or the charging pile charges electrical equipment such as new energy vehicles through the bidirectional charging circuit.

[0075] The bidirectional voltage conversion circuit may also be referred to as a bidirectional DC / DC module or a bidirectional DC / DC circuit.

[0076] For example, the number of bidirectional voltage conversion circuits is six, with a power of 25 kilowatts. Six sets of 25-kilowatt bidirectional power modules are connected in parallel to form a 150KW DC charging station. The parallel bidirectional voltage conversion circuits can adjust the number of bidirectional voltage conversion circuits operating according to the load weight, thereby improving discharge efficiency. The input voltage range of the multiple bidirectional voltage conversion circuits is 330V-430VDC, matching the voltage of their own battery packs; the output voltage range of the parallel modules is 200V-1000VDC, adapting to the voltage platforms of various new energy vehicles.

[0077] In an embodiment of the present disclosure, the charging pile controller is used to determine the number of bidirectional voltage conversion circuits to be put into use based on the charging power of the external device and the charging power of the battery pack.

[0078] Specifically, the charging pile controller connects multiple bidirectional voltage conversion circuits through CAN communication and configures the discharge current and discharge voltage of each bidirectional voltage conversion circuit so that the multiple bidirectional voltage conversion circuits work in a coordinated manner.

[0079] Specifically, the charging pile controller obtains the charging preparation and battery configuration information of the new energy vehicle through the handshake signal in the charging gun and the CAN bus, sets the output voltage (CV voltage value) and output current (CC current value) according to the battery information, and configures the normal charging logic (the charging logic is a charging rule that gradually transitions from the initial pre-charging stage to the charging stage).

[0080] During charging, the charging pile controller collects voltage and / or current signals from external devices, such as new energy vehicles. The controller adjusts the number of modules connected in parallel based on the charging power. At high power levels, the six bidirectional voltage conversion circuits operate simultaneously. As the charging power decreases, the number of parallel modules is gradually reduced, improving charging efficiency and reducing losses.

[0081] Exemplarily, the charging pile controller will appropriately put in and cut off the number of parallel modules according to the load (battery value of the object being charged and discharged) to improve the system's operating efficiency. For example, when the rated load is greater than 70%, all six bidirectional voltage conversion circuits are put into parallel use. When the rated load is less than 50%, two bidirectional voltage conversion circuits are cut off; when the rated load is less than 30%, four DCDC modules are switched.

[0082] 2 , in the bidirectional charging circuit according to the embodiment of the present disclosure, the bidirectional voltage conversion circuit includes: a first-stage bidirectional voltage conversion circuit 1021 and a second-stage bidirectional voltage conversion circuit 1022 ;

[0083] The first end of the first-stage bidirectional voltage conversion circuit 1021 is connected to the external device 104, the second end of the first-stage bidirectional voltage conversion circuit is connected to the first end of the second-stage bidirectional voltage conversion circuit 1022, and the second end of the second-stage bidirectional voltage conversion circuit is connected to the battery pack 103 of the DC charging pile.

[0084] On this basis, the charging pile controller is also used to control the voltage conversion multiples of the first-level bidirectional voltage conversion circuit and the second-level bidirectional voltage conversion circuit based on the collected first voltage signal of the external device, the second voltage signal of the battery pack, and the intermediate voltage signal between the first-level bidirectional voltage conversion circuit and the second-level bidirectional voltage conversion circuit.

[0085] The design of the two-stage bidirectional voltage conversion circuit can increase the voltage regulation range of the bidirectional voltage conversion, thereby increasing the voltage regulation range of the entire charging pile, further improving the load capacity of the charging pile, and increasing the charging current to improve the charging efficiency.

[0086] In the bidirectional charging circuit described in the embodiment of the present disclosure, specifically, the first-stage bidirectional voltage conversion circuit is a synchronous rectification circuit, and the second-stage bidirectional voltage conversion circuit is a bidirectional BUCK / BOOST circuit.

[0087] Specifically, the synchronous rectification circuit includes a resonant circuit, so that the synchronous rectification circuit operates in a resonant mode.

[0088] In the embodiment of the present disclosure, the charging pile controller in the bidirectional charging circuit is further used to:

[0089] According to the first voltage signal of the external device and the second voltage signal of the battery pack, as well as the charging stage, it is determined whether the synchronous rectification circuit enters the phase-shift DAB mode or the resonant mode.

[0090] In some embodiments, the synchronous rectification circuit adopts a CLLLC power unit.

[0091] In this way, the bidirectional voltage adopts a bidirectional DAB (CLLLC) + BUCK / BOOST series control mode, covering 200V-1000VDC.

[0092] Referring to FIG. 3 , in the bidirectional charging circuit according to an embodiment of the present disclosure, the synchronous rectification circuit includes a first full-bridge circuit, a transformer circuit, and a second full-bridge circuit connected in series.

[0093] The four switches in the first full-bridge circuit are respectively connected to the charging pile controller, and the four switches in the second full-bridge circuit are respectively connected to the charging pile controller;

[0094] A first end of the first full-bridge circuit is connected to an external device, and a second end of the second full-bridge circuit is connected to a bidirectional BUCK / BOOST circuit.

[0095] As shown in Fig. 3, the four switches in the first full-bridge circuit are M1H, M2H, M1L, and M2L, and the four switches in the second full-bridge circuit are M3H, M4H, M3L, and M4L.

[0096] The first full-bridge circuit and the second full-bridge circuit are both used to convert a DC voltage signal into an AC voltage signal and input the AC voltage signal into the transformer circuit; or, receive the AC voltage signal output by the transformer circuit and convert the AC voltage signal into a DC voltage signal;

[0097] The transformer circuit is used to receive an AC voltage signal, perform voltage transformation on it, and output the transformed AC voltage signal.

[0098] In the bidirectional charging circuit described in the embodiment of the present disclosure, the transformer circuit includes a first transformer side circuit and a second transformer side circuit;

[0099] The first transformer side circuit includes a first resonant capacitor C2, a first resonant inductor L1 and a first transformer coil connected in series;

[0100] The second transformer-side circuit includes a second resonant capacitor C3, a second resonant inductor L2, and a second transformer coil connected in series.

[0101] In the bidirectional charging circuit described in the embodiment of the present disclosure, the transformer circuit includes two resonant current collection units, and the first transformer-side circuit and the second transformer-side circuit are each connected in series with a resonant current collection unit;

[0102] The two resonant current acquisition units are electrically connected to the charging pile controller respectively.

[0103] Based on the current signal collected by the resonant current collection unit, the commutation of the bridge circuit at both ends of the transformer circuit is controlled.

[0104] In the embodiment of the present disclosure, referring to FIG. 3 , the two resonant current acquisition units use a current sensor Ipri_t and a current sensor Ipri_s.

[0105] Referring to FIG4 , in the bidirectional charging circuit according to an embodiment of the present disclosure, the bidirectional BUCK / BOOST circuit includes: an intermediate-side boost-buck switching circuit, a boost-buck inductor, a battery-side boost-buck switching circuit, and a boost-buck capacitor.

[0106] The intermediate side boost-buck switch switching circuit is connected to the second end of the synchronous rectification circuit, and the cutout of the intermediate side boost-buck switch switching circuit is connected to the cutout of the battery side boost-buck switch switching circuit through the boost-buck inductor; the battery side boost-buck switch switching circuit is connected in parallel with the boost-buck capacitor, and the boost-buck capacitor is connected in parallel at both ends of the battery pack.

[0107] Specifically, the intermediate side boost-buck switching circuit and the battery side boost-buck switching circuit in the bidirectional BUCK / BOOST circuit in the bidirectional charging circuit are electrically connected to the charging pile controller to achieve switching of multiple working modes under the control of the charging pile controller;

[0108] The multiple operating modes include: a BUCK mode when charging the battery pack, a BOOST mode when charging the battery pack; a BUCK mode when discharging the battery pack, and a BOOST mode when discharging the battery pack.

[0109] In the disclosed embodiment, the intermediate-side boost-buck switch switching circuit includes two boost-buck switches connected in series, with the cutout being between the two boost-buck switches;

[0110] The battery side boost-buck switch switching circuit includes two boost-buck switches connected in series, and the cutout is between the two boost-buck switches.

[0111] As shown in FIG4 , the two series-connected boost-buck switches on the middle side are respectively a boost-buck switch M5H and a boost-buck switch M5L, and the two series-connected boost-buck switches on the battery side are respectively a boost-buck switch M6H and a boost-buck switch M6L; the boost-buck inductor is inductor L3, and the boost-buck capacitor is capacitor C5.

[0112] Please refer to Figures 2, 3, and 4. The bidirectional voltage conversion circuit is divided into two stages: the front-stage circuit M1H / M1L, M2H / M2L, M3H / M3L, and M4H / M4L four SiC modules form a complete symmetrical bidirectional bridge arm, which can operate in both DAB and CLLLC states, achieving maximum operating efficiency in the CLLLC state; the back-stage circuit M5H / M5L and M6H / M6L two SiC modules form a symmetrical BUCK / BOOST circuit to expand the voltage regulation range.

[0113] The following describes the battery pack charging and discharging process of the bidirectional charging circuit with reference to FIG2 , FIG3 and FIG4 .

[0114] The battery pack charging process is as follows: the synchronous rectification circuit (the embodiment of the present disclosure is illustrated by taking the CLLLC power unit as an example, hereinafter referred to as the CLLLC power unit or CLLLC unit) sets the output voltage (Vmid) and output current (Imid), and then starts the PWM1A / 1B, PWM2A / 2B pulses, and energy flows from the DC port side (left socket) to the middle section, and the voltage-stabilizing capacitor C4 keeps the voltage of the middle section stable; PWM3A / 3B and PWM4A / 4B work in the synchronous rectification state, and the synchronous rectification signal is extracted from the Ipri_s current sensor. According to the synchronous rectification signal, it is judged whether the current in the transformer circuit is positive or negative. When the transformer current is positive, PWM3A / PWM4B outputs a high level; when the transformer current is negative, PWM3B / PWM4A outputs a high level, realizing the synchronous rectification function, thereby realizing the first-level DC voltage conversion.

[0115] The second-stage bidirectional buck / boost circuit sets the charging voltage (CV) and current (CC) for the internal battery pack and outputs pulses based on the charging configuration: in buck mode, the duty cycle of PWM5A is controlled, PWM5B operates in the freewheeling state, PWM6A is normally open, and PWM6B is normally closed. When operating in boost mode, PWM5A is normally open, PWM5B is normally closed, the duty cycle of PWM6B is controlled, and PWM6A operates in the freewheeling state.

[0116] The battery pack discharge process is as follows:

[0117] The bidirectional buck / boost circuit sets the discharge voltage (CV) and current (CC) for the middle section and outputs pulses based on the discharge configuration. In buck mode, the duty cycle of PWM6A is controlled, PWM6B operates in the freewheeling state, PWM5A is normally open, and PWM5B is normally closed. In boost mode, PWM6A is normally open, PWM6B is normally closed, the duty cycle of PWM5B is controlled, and PWM5A operates in the freewheeling state.

[0118] The CLLC unit sets the DC port's output voltage (Vpri_H) and output current (Ipri_H), then starts the PWM3A / 3B and PWM4A / 4B pulses. Energy flows from the middle segment to the DC port side (left socket), and the voltage-stabilizing capacitor C1 maintains the DC port-side voltage stability. PWM1A / 1B and PWM2A / 2B operate in a synchronous rectification state. The synchronous rectification signal is extracted from the Ipri_t current sensor. When the transformer current is positive, PWM1A / PWM2B outputs a high level. When the transformer current is negative, PWM1B / PWM2A outputs a high level, implementing the synchronous rectification function.

[0119] In the disclosed embodiment, the charging pile controller can also determine whether the synchronous rectification circuit enters the phase-shift DAB mode or the resonant mode based on the first voltage signal of the external device and the second voltage signal of the battery pack, as well as the charging stage. Specifically, the use of the phase-shift DAB mode in the charging and discharging state: the CLLLC unit will operate at the highest frequency in the initial startup stage. The sudden appearance of the highest frequency will also cause current shock. In order to reduce the current shock, the phase-shift DAB mode can be entered before the CLLC mode is turned on, and the duty cycle can be gradually increased. When the duty cycle reaches 100%, it is switched to the CLLC control mode. In the phase-shift DAB mode, the current is increased from the zero stage to reduce the current shock to the system.

[0120] Here, the charging stage includes the battery pack charging stage or the external device charging stage, which can also be described as the battery pack charging and discharging stage.

[0121] That is, determining whether the synchronous rectification circuit enters the phase-shift DAB mode or the resonant mode according to the first voltage signal of the external device and the second voltage signal of the battery pack, as well as the charging stage, includes:

[0122] According to the first voltage signal of the external device and the second voltage signal of the battery pack, when starting charging and discharging, the synchronous rectification circuit enters the phase-shift DAB mode;

[0123] When the duty cycle of the current signal in the synchronous rectification circuit reaches 100%, the resonant mode is switched.

[0124] When multiple bidirectional voltage conversion circuits (bidirectional DC / DC modules) operate in parallel, in order to reduce the ripple current on the high-voltage port side and the battery side, it is necessary to perform phase shift control on the bidirectional voltage conversion circuits.

[0125] Based on this, in the embodiments of the present disclosure, the bidirectional charging circuit and the charging pile controller are further used to:

[0126] When the charging pile controller controls N bidirectional voltage conversion circuits to work in parallel, the number N of bidirectional voltage conversion circuits working in parallel is sent to the bidirectional voltage conversion circuit;

[0127] The bidirectional voltage conversion circuit is configured to determine a phase shift angle of the bidirectional voltage conversion circuit based on the number N, and adjust a phase of an output current of the bidirectional voltage conversion circuit based on the phase shift angle.

[0128] Specifically, determining the phase shift angle of the bidirectional voltage conversion circuit based on the number N includes:

[0129] Determining a phase shift angle of a bidirectional BUCK / BOOST circuit in the bidirectional voltage conversion circuit based on the number N;

[0130] When the synchronous rectification circuit in the bidirectional voltage conversion circuit includes a resonant circuit and the synchronous rectification circuit operates at a resonant frequency, the phase shift angle of the synchronous rectification circuit in the bidirectional voltage conversion circuit is determined based on the number N.

[0131] Please refer to Figure 5, which shows a schematic diagram of the phase shift control process described in an embodiment of the present disclosure; N bidirectional DC / DC modules work in parallel and work in a phase shift mode: the phase shift angle is 360 / N, that is, when two modules work in parallel, the phase shift is 360 / 2=180 degrees, when three modules work in parallel, the phase shift is 360 / 3=120 degrees,... when six modules work in parallel, the phase shift angle is 360 / 6=60 degrees; the more parallel modules there are, the smaller the port ripple current amplitude is, on the one hand, the DC characteristics are better, and on the other hand, the design size of the EMI unit is reduced, the system cost is reduced, and the heat generation of the magnetic device is reduced.

[0132] During the charging and discharging process, the charging pile controller sends the number of parallel modules to each bidirectional DC / DC module, and the bidirectional DC / DC module determines the corresponding count value.

[0133] When SYNC_in is input, the bidirectional DC / DC module loads the phase-shift COUNTER value; when the COUTER value of the bidirectional DC / DC module is 0, the module generates a SYNC_out pulse signal.

[0134] For the buck / boost circuit, the period is fixed, making phase adjustment easy using the synchronization (SYNC) function. Refer to Figure 6, which shows a schematic diagram of the phase-shift waveforms of the bidirectional buck / boost circuit described in an embodiment of the present disclosure. When the SYNC_INX signal is input, the phase-shift count value is set. When the count value is 0, the SYNC_OUTX signal is output.

[0135] Because the CLLLC unit operates in frequency regulation mode, during the startup phase, each parallel CLLLC unit slides from the highest frequency to the resonant frequency (300KHz -> 140KHz), ultimately reaching the resonant frequency (140KHz) with the highest operating efficiency. During the frequency sliding phase, each module operates in a light-load segment with discrete characteristics. After each CLLLC unit reaches the resonant frequency point, multiple modules operate in phase-shift mode. Please refer to Figure 7, which shows a schematic diagram of the phase-shift waveform of the CLLLC unit described in the embodiment of the present disclosure.

[0136] When external power demand decreases and some modules need to be disconnected from parallel, or a module fails and needs to be disconnected from parallel, the corresponding module stops power conversion and the synchronization signal of the faulty module is short-circuited. The remaining parallel modules reallocate the phase shift angle and readjust the phase shift counter value. When the SYNC_INX signal is input, the phase shift counter value is set. When the counter value is 0, the SYNC_OUTX signal is output.

[0137] In an embodiment of the present disclosure, when the bidirectional charging circuit is applied to a DC charging pile, the battery pack includes a plurality of sub-battery modules connected in series and a plurality of heat dissipation layers;

[0138] At least two sub-battery modules are placed side by side on each heat dissipation layer plate, a first air duct is reserved between the sub-battery modules placed side by side, and a second air duct is reserved between the heat dissipation layers.

[0139] The heat dissipation layer plate is provided with heat dissipation fins.

[0140] That is to say, a heat dissipation channel is provided inside the battery pack: each layer of battery cells is placed on an aluminum plate with fins, and the fins are one of the wind channels for heat dissipation; at the same time, wind channels are reserved between the side-by-side sub-units to minimize the temperature of the battery cells.

[0141] Referring to FIG8 , in the embodiment of the present disclosure, a first heat dissipation mechanism is further provided in the charging pile; the first heat dissipation mechanism includes a liquid cooler 801 and a fan 802;

[0142] The air outlet of the fan 802 faces the second air duct inlet of the battery pack 103, and the heat exchange plate of the liquid cooler 801 is located between the air outlet of the fan 802 and the second air duct inlet of the battery pack 103, so as to blow the cold air at the heat exchange plate of the liquid cooler 801 into the second air duct of the battery pack 103.

[0143] The fan 802 is connected to the fan control terminal of the charging pile controller 101 so that the charging pile controller 101 controls the rotation speed of the fan 802 according to the charging current.

[0144] The liquid cooler may also use a heat exchanger.

[0145] The greater the load, the more heat is generated, the higher the fan speed is, and the better the heat dissipation effect is. Conversely, the smaller the load, the less heat is generated, and the lower the fan speed is, thus saving the electricity of the charging pile.

[0146] 9 , in the embodiment of the present disclosure, a second heat dissipation mechanism is further provided in the charging pile, and the second heat dissipation mechanism includes a liquid cooling layer plate 901 , a refrigerator 902 and a radiator 903 ;

[0147] Each voltage conversion circuit in the bidirectional charging circuit is placed on a liquid cooling layer 901; the refrigerator 902 delivers cooling liquid through the liquid cooling layer 901 to dissipate heat for each voltage conversion circuit. The liquid cooling layer 901 returns water to the refrigerator 902, and the refrigerator 902 then delivers cooling liquid to the radiator 903. The radiator 903 returns water to the refrigerator 902.

[0148] Specifically, in the disclosed embodiment, the bottom aluminum plate of a single 25kW DC / DC module is pressed against a fixed liquid-cooled aluminum plate. A chiller pumps refrigerant through the plate to dissipate heat from the module. When the module requires maintenance, the screws securing the plate are loosened to remove the DC / DC module. The liquid-cooled aluminum plate returns water to the chiller, raising the coolant temperature. The chiller then pumps the heated coolant to the radiator for heat dissipation. The radiator then returns water to the chiller, cooling the coolant temperature again.

[0149] In the embodiment of the present disclosure, the charging pile further includes a communication module, and the communication module is communicatively connected to the charging pile controller;

[0150] The communication module is used to receive a charging signal generated based on a user operation and send the charging signal to a charging pile controller, so that the charging pile controller charges the external device based on the charging signal.

[0151] The communication module may be a Bluetooth module, etc. The user operation may be scanning a QR code, inserting a coin, operating a touch screen, etc.

[0152] In the embodiment of the present disclosure, the DC charging pile is further provided with a fixing member and a power connector;

[0153] The battery pack is detachably mounted in the charging pile body via the fixing member, and the positive and negative electrodes of the battery pack are plug-in connected to the positive and negative electrode interfaces of the charging pile body via a power connector.

[0154] In the embodiment of the present disclosure, a plurality of temperature probes are provided in the battery pack to collect a plurality of temperature data in the battery pack and send the temperature data to the charging pile controller.

[0155] The charging pile controller collects the voltage signal, current signal and temperature data of the battery pack, and stops discharging when a single cell of the battery pack is undervoltage or the system is overheated.

[0156] Based on the same inventive concept, the embodiment of the present disclosure also provides a DC charging pile using the bidirectional charging circuit. Since the principle of solving the problem by the DC charging pile in the embodiment of the present disclosure is similar to that of the above-mentioned bidirectional charging circuit in the embodiment of the present disclosure, the implementation of the DC charging pile can refer to the implementation of the bidirectional charging circuit, and the repeated parts will not be repeated.

[0157] In an embodiment of the present disclosure, a DC charging pile is provided, comprising a charging pile body, a battery pack, and any of the bidirectional charging circuits described in the embodiments of the present disclosure;

[0158] The bidirectional charging circuit and battery pack are both located inside the charging pile body.

[0159] In some embodiments, the battery pack in the DC charging pile includes a plurality of sub-battery modules connected in series and a plurality of heat dissipation layers;

[0160] At least two sub-battery modules are placed side by side on each heat dissipation layer plate, a first air duct is reserved between the sub-battery modules placed side by side, and a second air duct is reserved between the heat dissipation layers.

[0161] In some embodiments, the heat dissipation layer plate in the DC charging pile is provided with heat dissipation fins.

[0162] In some embodiments, the charging pile in the DC charging pile includes a first heat dissipation mechanism; the first heat dissipation mechanism includes a liquid cooler and a fan;

[0163] The air outlet of the fan faces the inlet of the second air duct, and the heat exchange plate of the liquid cooler is located between the air outlet of the fan and the inlet of the second air duct, so as to blow the cold air at the heat exchange plate of the liquid cooler into the second air duct.

[0164] In some embodiments, in the DC charging pile, the fan is connected to the fan control terminal of the charging pile controller, so that the charging pile controller controls the fan speed according to the charging current.

[0165] In some embodiments, the charging pile further includes a second heat dissipation mechanism, which includes a liquid cooling layer plate, a refrigerator, and a radiator;

[0166] Each voltage conversion circuit in the bidirectional charging circuit is placed on a liquid cooling plate; the refrigerator delivers cooling liquid through the liquid cooling plate to dissipate heat for each voltage conversion circuit, the liquid cooling plate returns water to the refrigerator, the refrigerator then delivers cooling liquid to the radiator, and the radiator returns water to the refrigerator.

[0167] In some embodiments, the DC charging pile further comprises a communication module, and the communication module is communicatively connected to the charging pile controller;

[0168] The communication module is used to receive a charging signal generated based on a user operation and send the charging signal to a charging pile controller, so that the charging pile controller charges the external device based on the charging signal.

[0169] In some embodiments, in the DC charging pile, the charging pile further includes a fixing member and a power connector;

[0170] The battery pack is detachably mounted in the charging pile body via the fixing member, and the positive and negative electrodes of the battery pack are plug-in connected to the positive and negative electrode interfaces of the charging pile body via a power connector.

[0171] In some embodiments, in the DC charging pile, a plurality of temperature probes are provided in the battery pack to collect a plurality of temperature data in the battery pack and send the temperature data to the charging pile controller.

[0172] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working processes of the systems and devices described above can refer to the corresponding processes in the method embodiments, and will not be repeated in this disclosure. In the several embodiments provided in the present disclosure, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0173] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed across multiple network elements. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0174] In addition, each functional unit in each embodiment of the present disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0175] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present disclosure, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a platform server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0176] The above are only specific embodiments of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims. Industrial Applicability

[0177] The present disclosure provides a bidirectional charging circuit and a DC charging pile, wherein the bidirectional charging circuit includes a plurality of bidirectional voltage conversion circuits and a charging pile controller connected in parallel; the first ends of the plurality of bidirectional voltage conversion circuits are all connected to an external device, and the second ends of the plurality of bidirectional voltage conversion circuits are all connected to a battery pack of the DC charging pile; wherein the external device is a DC power supply or a charging device; the signal acquisition end of the charging pile controller is connected to a first signal output end of the external device and a second signal output end of the battery pack, and the control signal output end of the charging pile controller is connected to a control signal input end of the plurality of bidirectional voltage conversion circuits. Based on this, a plurality of bidirectional voltage conversion circuits are connected in parallel when the battery pack is charged and discharged, thereby improving the load capacity of the charging pile and increasing the charging current, thereby improving the charging efficiency.

[0178] Furthermore, it is understood that the bidirectional charging circuit and DC charging pile of the present disclosure are reproducible and can be used in a variety of industrial applications. For example, the bidirectional charging circuit and DC charging pile of the present disclosure can be used in the field of charging piles.

Claims

1. A bidirectional charging circuit, Features: The circuit comprises: a plurality of bidirectional voltage conversion circuits and a charging pile controller connected in parallel; The first ends of the plurality of bidirectional voltage conversion circuits are all connected to an external device, and the second ends of the plurality of bidirectional voltage conversion circuits are all connected to a battery pack of a DC charging pile; wherein the external device is a DC power supply or a charging device; The signal acquisition end of the charging pile controller is connected to the first signal output end of the external device and the second signal output end of the battery pack, and the control signal output end of the charging pile controller is connected to the control signal input end of the multiple bidirectional voltage conversion circuits.

2. The bidirectional charging circuit according to claim 1, Features: The charging pile controller is used for: The number of bidirectional voltage conversion circuits to be used is determined according to the charging power of the external device and the charging power of the battery pack.

3. The bidirectional charging circuit according to claim 1, Features: The bidirectional voltage conversion circuit comprises: a first-stage bidirectional voltage conversion circuit and a second-stage bidirectional voltage conversion circuit; The first end of the first-level bidirectional voltage conversion circuit is connected to an external device, the second end of the first-level bidirectional voltage conversion circuit is connected to the first end of the second-level bidirectional voltage conversion circuit, and the second end of the second-level bidirectional voltage conversion circuit is connected to the battery pack of the DC charging pile.

4. The bidirectional charging circuit according to claim 3, Features: The charging pile controller is also used for: Based on the collected first voltage signal of the external device, the second voltage signal of the battery pack, and the intermediate voltage signal between the first-level bidirectional voltage conversion circuit and the second-level bidirectional voltage conversion circuit, the voltage conversion multiples of the first-level bidirectional voltage conversion circuit and the second-level bidirectional voltage conversion circuit are controlled.

5. The bidirectional charging circuit according to claim 4, Features: The first-stage bidirectional voltage conversion circuit is a synchronous rectification circuit, and the second-stage bidirectional voltage conversion circuit is a bidirectional BUCK / BOOST circuit.

6. The bidirectional charging circuit according to claim 5, Features: The charging pile controller is also used for: When the charging pile controller controls N bidirectional voltage conversion circuits to work in parallel, the number N of bidirectional voltage conversion circuits working in parallel is sent to the bidirectional voltage conversion circuit; The bidirectional voltage conversion circuit is used to: determine a phase shift angle of the bidirectional voltage conversion circuit based on the number N, and adjust a phase of an output current of the bidirectional voltage conversion circuit based on the phase shift angle.

7. The bidirectional charging circuit according to claim 6, Features: Determining a phase shift angle of the bidirectional voltage conversion circuit based on the number N includes: Determine a phase shift angle of a bidirectional BUCK / BOOST circuit in the bidirectional voltage conversion circuit based on the number N; When the synchronous rectification circuit in the bidirectional voltage conversion circuit includes a resonant circuit and the synchronous rectification circuit operates at a resonant frequency, the phase shift angle of the synchronous rectification circuit in the bidirectional voltage conversion circuit is determined based on the number N.

8. The bidirectional charging circuit according to claim 5, Features: The synchronous rectification circuit includes a resonance circuit so that the synchronous rectification circuit operates in a resonance mode.

9. The bidirectional charging circuit according to claim 8, Features: The charging pile controller is also used for: According to the first voltage signal of the external device and the second voltage signal of the battery pack, as well as the charging stage, it is determined whether the synchronous rectification circuit enters the phase-shift DAB mode or the resonance mode.

10. The bidirectional charging circuit according to claim 8, Features: The synchronous rectification circuit comprises a first full-bridge circuit, a transformer circuit and a second full-bridge circuit connected in series in sequence; The four switches in the first full-bridge circuit are respectively connected to the charging pile controller, and the four switches in the second full-bridge circuit are respectively connected to the charging pile controller; A first end of the first full-bridge circuit is connected to an external device, and a second end of the second full-bridge circuit is connected to a bidirectional BUCK / BOOST circuit.

11. The bidirectional charging circuit according to claim 10, Features: The transformer circuit includes a first transformer side circuit and a second transformer side circuit; The first transformer side circuit comprises a first resonant capacitor, a first resonant inductor and a first transformer coil connected in series in sequence; The second transformer side circuit includes a second resonant capacitor, a second resonant inductor and a second transformer coil which are connected in series in sequence.

12. The bidirectional charging circuit according to claim 11, Features: The transformer circuit comprises two resonant current collection units, and the first transformer side circuit and the second transformer side circuit are respectively connected in series with a resonant current collection unit; The two resonant current collection units are electrically connected to the charging pile controllers respectively.

13. The bidirectional charging circuit according to claim 5, Features: The bidirectional BUCK / BOOST circuit includes: an intermediate side boost-buck switch switching circuit, a boost-buck inductor, a battery side boost-buck switch switching circuit, and a boost-buck capacitor; The intermediate side boost-buck switch switching circuit is connected to the second end of the synchronous rectification circuit, and the cutout of the intermediate side boost-buck switch switching circuit is connected to the cutout of the battery side boost-buck switch switching circuit through the boost-buck inductor; the battery side boost-buck switch switching circuit is connected in parallel with the boost-buck capacitor, and the boost-buck capacitor is connected in parallel at both ends of the battery pack.

14. The bidirectional charging circuit according to claim 13, Features: The intermediate side boost-buck switch switching circuit and the battery side boost-buck switch switching circuit in the bidirectional BUCK / BOOST circuit are both electrically connected to the charging pile controller to achieve switching of multiple working modes under the control of the charging pile controller; The multiple working modes include: a BUCK mode when charging the battery pack, a BOOST mode when charging the battery pack; a BUCK mode when discharging the battery pack, and a BOOST mode when discharging the battery pack.

15. The bidirectional charging circuit according to claim 13, Features: The intermediate-side boost-buck switch switching circuit includes two boost-buck switches connected in series, with the cutout being between the two boost-buck switches; The battery side boost-buck switch switching circuit includes two boost-buck switches connected in series, and the cutout is between the two boost-buck switches.

16. A DC charging pile, It is characterized in that It comprises a charging pile body, a battery pack and a bidirectional charging circuit as described in any one of claims 1 to 15; The bidirectional charging circuit and the battery pack are both located inside the charging pile body.

17. The DC charging pile according to claim 16, It is characterized in that The battery pack includes a plurality of sub-battery modules connected in series and a plurality of heat dissipation layer plates; Among them, at least two sub-battery modules are placed side by side on each heat dissipation layer plate, a first air duct is reserved between the sub-battery modules placed side by side, and a second air duct is reserved between the heat dissipation layer plates.

18. The DC charging pile according to claim 17, It is characterized in that The heat dissipation layer plate is provided with heat dissipation fins.

19. The DC charging pile according to claim 17, It is characterized in that The charging pile includes a first heat dissipation mechanism; the first heat dissipation mechanism includes a liquid cooler and a fan; The air outlet of the fan faces the inlet of the second air duct, and the heat exchange plate of the liquid cooler is located between the air outlet of the fan and the inlet of the second air duct, so as to blow the cold air at the heat exchange plate of the liquid cooler into the second air duct.

20. The DC charging pile according to claim 19, It is characterized in that The fan is connected to the fan control terminal of the charging pile controller so that the charging pile controller controls the fan speed according to the charging current.

21. The DC charging pile according to claim 16, It is characterized in that The charging pile also includes a second heat dissipation mechanism, which includes a liquid cooling layer plate, a refrigerator and a radiator; Each voltage conversion circuit in the bidirectional charging circuit is placed on a liquid cooling plate; the refrigerator delivers cooling liquid through the liquid cooling plate to dissipate heat for each voltage conversion circuit, the liquid cooling plate returns water to the refrigerator, the refrigerator then delivers cooling liquid to the radiator, and the radiator returns water to the refrigerator.

22. The DC charging pile according to claim 16, It is characterized in that The charging pile also includes a communication module, and the communication module is communicatively connected with the charging pile controller; The communication module is used to receive a charging signal generated based on a user operation, and send the charging signal to a charging pile controller, so that the charging pile controller charges the external device based on the charging signal.

23. The DC charging pile according to claim 16, It is characterized in that The charging pile also includes a fixing part and a power connector; The battery pack is detachably mounted in the charging pile body via the fixing member, and the positive and negative electrodes of the battery pack are plug-in connected to the positive and negative electrode interfaces of the charging pile body via a power connector.

24. The DC charging pile according to claim 16, It is characterized in that The battery pack is provided with a plurality of temperature probes to collect a plurality of temperature data in the battery pack and send the temperature data to the charging pile controller.

Images