High pressure circuit and vehicle

Abstract

The application discloses a high-voltage loop and a vehicle. According to the embodiment of the application, the switching of the series-parallel connection mode of the first power battery and the second power battery is realized by using a bidirectional converter. When neither of the two power batteries fails, that is, in a normal working condition, the first end and the third end of the bidirectional converter are connected, so that the first power battery and the second power battery are connected in series, and the two power batteries supply power to the load together. When one of the two power batteries fails, that is, in a failure working condition, the first end and the second end of the bidirectional converter are connected, and the third end and the fourth end of the bidirectional converter are connected, so that the first power battery and the second power battery are connected in parallel. The power battery which does not fail supplies power to the load, so as to drive the vehicle to travel to a repair station or a safe position, prevent the running vehicle from suddenly stopping, and be favorable to improving the driving safety.

Description

Technical Field

[0001] This application belongs to the field of battery management technology, and in particular relates to a high-voltage circuit and a vehicle. Background Technology

[0002] With the rapid development of the new energy vehicle industry, higher requirements have been placed on vehicle range and charging time. Therefore, the 800V battery system has been introduced, which can effectively improve the vehicle's range and shorten the charging time.

[0003] In related technologies, most vehicle battery systems are single battery packs. When the battery system fails, it cannot supply power to the drive motor, preventing the vehicle from reaching a repair shop. This is especially true for vehicles that are already in motion, where abnormal battery power can cause the vehicle to lose power and suddenly stop in the middle of the road, increasing driving risks. Utility Model Content

[0004] This application provides a high-voltage circuit and a vehicle, which uses a bidirectional converter to switch between the series and parallel connection of the first power battery and the second power battery. When one of the two power batteries fails, the first power battery and the second power battery are connected in parallel. The power battery that has not failed supplies power to the load to drive the vehicle to a repair station or a safe location, preventing the vehicle from stopping suddenly and improving driving safety.

[0005] On one hand, embodiments of this application provide a high-voltage circuit, including: First power battery, second power battery, and bidirectional converter; Wherein, the first terminal of the first power battery is connected to the first end of the bidirectional converter, and the second terminal of the first power battery is connected to the first end of the load; the first terminal of the second power battery is connected to the second end of the load, and the second terminal of the second power battery is connected to the third end of the bidirectional converter; the second end of the bidirectional converter is connected to the first connection point, and the fourth end of the bidirectional converter is connected to the second connection point; the first connection point is the connection point between the first terminal of the second power battery and the load, and the second connection point is the connection point between the second terminal of the first power battery and the load; The bidirectional converter is configured such that, under normal operating conditions, the first and third terminals of the bidirectional converter are connected; under fault operating conditions, the first and second terminals of the bidirectional converter are connected, and the third and fourth terminals of the bidirectional converter are connected.

[0006] According to any of the foregoing embodiments of this application, the high-voltage circuit further includes: The first switch is located on the branch between the first power battery and the second connection point. The second switch is located on the branch between the second power battery and the first connection point.

[0007] According to any of the foregoing embodiments of this application, the high-voltage circuit further includes: First pre-charge module; The first pre-charge module is disposed on the branch between the first power battery and the load, and the first pre-charge module is connected in parallel with the first switch; The second pre-charge module is located on the branch between the second power battery and the load, and is connected in parallel with the second switch. The first capacitor; the first terminal of the first capacitor is connected to the first terminal of the load, and the second terminal of the first capacitor is connected to the second terminal of the load.

[0008] According to any of the foregoing embodiments of this application, the first pre-charge module includes a first pre-charge switch and a first pre-charge resistor. One end of the first pre-charge resistor is connected to the second electrode of the first power battery and the first end of the first switch, respectively. The other end of the first pre-charge resistor is connected to the first end of the first pre-charge switch, and the second end of the first pre-charge switch is connected to the second end of the first switch and the first end of the load, respectively. The second precharge module includes a second precharge switch and a second precharge resistor. One end of the second precharge resistor is connected to the first terminal of the second power battery and the first terminal of the second switch, respectively. The other end of the second precharge resistor is connected to the first terminal of the second precharge switch. The second terminal of the second precharge switch is connected to the second terminal of the second switch and the second terminal of the load, respectively.

[0009] According to any of the foregoing embodiments of this application, the high-voltage circuit further includes: A reverse precharge DC-DC converter, wherein the first terminal of the reverse precharge DC-DC converter is connected to the first terminal of the load, the second terminal of the reverse precharge DC-DC converter is connected to the second terminal of the load, and the third terminal of the reverse precharge DC-DC converter is connected to a DC power supply. The second capacitor; the first terminal of the second capacitor is connected to the first terminal of the load, and the second terminal of the second capacitor is connected to the second terminal of the load.

[0010] According to any of the foregoing embodiments of this application, the high-voltage circuit further includes: The third switch is located on the branch between the first switch and the first end of the charging interface; And / or, a fourth switch, which is located on the branch between the second switch and the second end of the charging interface.

[0011] According to any of the foregoing embodiments of this application, the load includes an upper bridge arm module, a lower bridge arm module and a three-phase inductor. The first end of the upper bridge arm module is connected to the second switch, the second end of the upper bridge arm module is connected to the first end of the lower bridge arm module, the second end of the lower bridge arm module is connected to the first switch, and the connection point between the upper bridge arm module and the lower bridge arm module is connected to the first end of the three-phase inductor. The high-voltage circuit also includes a fifth switch, which is located on the branch between the third terminal of the bidirectional converter and the three-phase inductor.

[0012] According to any of the foregoing embodiments of this application, the high-voltage circuit further includes: The first protection module is located on the branch between the positive terminal of the first power battery and the bidirectional converter; The second protection module is located on the branch between the positive terminal of the second power battery and the second switch.

[0013] According to any of the foregoing embodiments of this application, the high-voltage circuit further includes: A current collector is disposed at least at one of the following: the branch between the negative terminal of the first power battery and the first switch; the branch between the second connection point and the load; and the branch between the third terminal of the converter and the second power battery.

[0014] On the other hand, this application also provides a vehicle, including any of the above-mentioned high-voltage circuits.

[0015] The high-voltage circuit and vehicle provided in this application embodiment utilize a bidirectional converter to switch between the series and parallel connection of the first and second power batteries. When neither power battery is faulty (normal operating condition), the first and third terminals of the bidirectional converter are connected, connecting the first and second power batteries in series, and both supply power to the load. When one of the two power batteries is faulty (faulty operating condition), the first and second terminals of the bidirectional converter, as well as the third and fourth terminals of the bidirectional converter, are connected, connecting the first and second power batteries in parallel. The power battery that is not faulty supplies power to the load to drive the vehicle to a repair station or a safe location, preventing the vehicle from suddenly stopping and improving driving safety. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a high-voltage circuit provided in an embodiment of this application; Figure 2 This is a schematic diagram of another high-voltage circuit provided in an embodiment of this application; Figure 3 This is a schematic diagram of another high-voltage circuit provided in the embodiments of this application; Figure 4 This is a schematic diagram of another high-voltage circuit provided in the embodiments of this application; Figure 5 This is a schematic diagram of another high-voltage circuit provided in the embodiments of this application; Figure 6 This is a schematic diagram of the current flow path of the first power battery and the second power battery connected in series to provide power according to an embodiment of this application; Figure 7 This is a schematic diagram of the current flow path of the first power battery failure and the second power battery supply provided in the embodiments of this application; Figure 8 This is a schematic diagram of the current flow path of the first power battery supplying power in the event of a second power battery failure, as provided in an embodiment of this application. Figure 9 This is a schematic diagram of the current flow path for the first power battery and the second power battery in series charging according to an embodiment of this application; Figure 10 This is a schematic diagram of the current flow path for a first power battery failure and a second power battery charging, provided in an embodiment of this application. Figure 11 This is a schematic diagram of the current flow path for a second power battery failure and a first power battery charging, provided in an embodiment of this application. Figure 12 This is a schematic diagram of the current flow path of the first power battery and the second power battery being charged in parallel according to an embodiment of this application; Figure 13 This is a schematic diagram of the current flow path in the first stage of low-frequency self-heating provided in the embodiments of this application; Figure 14 This is a schematic diagram of the current flow path in the second stage of low-frequency self-heating provided in the embodiments of this application; Figure 15 This is a schematic diagram of the current change and upper and lower bridge arm control timing during the low-frequency self-heating process provided in the embodiments of this application. Detailed Implementation

[0018] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0019] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0020] To address the technical problems raised in the background art, embodiments of this application provide a high-voltage circuit and a vehicle. The high-voltage circuit includes: a first power battery, a second power battery, and a bidirectional converter; a first terminal of the first power battery is connected to a first end of the bidirectional converter, and a second terminal of the first power battery is connected to a first end of a load; a first terminal of the second power battery is connected to a second end of the load, and a second terminal of the second power battery is connected to a third end of the bidirectional converter; a second end of the bidirectional converter is connected to a first connection point, and a fourth end of the bidirectional converter is connected to a second connection point; the first connection point is the connection point between the first terminal of the second power battery and the load, and the second connection point is the connection point between the second terminal of the first power battery and the load; the bidirectional converter is configured such that, under normal operating conditions, it connects the first end and the third end of the bidirectional converter; and under fault operating conditions, it connects the first end and the second end of the bidirectional converter, and also connects the third end and the fourth end of the bidirectional converter. With this configuration, this application utilizes a bidirectional converter to switch between the series and parallel connection of the first and second power batteries. When neither power battery is faulty (normal operating condition), the first and third terminals of the bidirectional converter are connected, connecting the first and second power batteries in series, allowing them to supply power to the load together. When one of the power batteries is faulty (faulty operating condition), the first and second terminals of the bidirectional converter, as well as the third and fourth terminals, are connected, connecting the first and second power batteries in parallel. The power battery that is not faulty supplies power to the load, driving the vehicle to a repair shop or a safe location, preventing the vehicle from suddenly stopping and improving driving safety.

[0021] The high-voltage circuit and vehicle provided in the embodiments of this application will be described below.

[0022] Figure 1 A schematic diagram of a high-voltage circuit according to an embodiment of this application is shown. Figure 1 As shown, the high-voltage circuit may include: a first power battery B1, a second power battery B2, and a bidirectional converter 1.

[0023] In this configuration, the first terminal of the first power battery B1 is connected to the first terminal a of the bidirectional converter 1, and the second terminal of the first power battery B1 is connected to the first terminal of the load 2; the first terminal of the second power battery B2 is connected to the second terminal of the load 2, and the second terminal of the second power battery B2 is connected to the third terminal c of the bidirectional converter 1. One of the first and second terminals is a positive terminal, and the other is a negative terminal.

[0024] In one example, the difference between the first nominal voltage of the first power battery B1 and the second nominal voltage of the second power battery B2 is less than or equal to a set voltage threshold. For example, the first nominal voltage of the first power battery B1 and the second nominal voltage of the second power battery B2 are equal, both being 400V.

[0025] In one example, the first power battery B1 includes at least one cell, and the second power battery B2 includes at least one cell. The number of cells in the first power battery B1 is equal to the number of cells in the second power battery B2, such that the voltage of the first power battery B1 is equal to the voltage of the second power battery B2.

[0026] The second end b of the bidirectional converter 1 is connected to the first connection point m, and the fourth end d of the bidirectional converter 1 is connected to the second connection point n; the first connection point m is the connection point between the first pole of the second power battery B2 and the load 2, and the second connection point n is the connection point between the second pole of the first power battery B1 and the load 2.

[0027] The bidirectional converter 1 can be configured such that, under normal operating conditions, the first terminal a and the third terminal c of the bidirectional converter 1 are connected, connecting the first power battery B1 and the second power battery B2 in series. When neither power battery is faulty, i.e., under normal operating conditions, the first terminal a and the third terminal c of the bidirectional converter 1 are connected, connecting the first power battery B1 and the second power battery B2 in series, and both power batteries supply power to the load 2.

[0028] For example, the voltage of the first power battery B1 and the voltage of the second power battery B2 are both 400V. Under normal operating conditions, if the load is an 800V high-voltage platform component, the first terminal a and the third terminal c of the bidirectional converter 1 are connected, and the first power battery B1 and the second power battery B2 are powered in series. If the load is a 400V high-voltage platform component, the first terminal a and the second terminal b of the bidirectional converter 1 are connected, and the third terminal c and the fourth terminal d of the bidirectional converter 1 are also connected, and the first power battery B1 and the second power battery B2 are powered in parallel.

[0029] The bidirectional converter 1 can also be configured to connect the first terminal a and the second terminal b, and the third terminal c and the fourth terminal d of the bidirectional converter 1 under fault conditions. When one of the two power batteries fails, i.e., under fault conditions, connecting the first terminal a and the second terminal b, and connecting the third terminal c and the fourth terminal d of the bidirectional converter 1, connects the first power battery B1 and the second power battery B2 in parallel. The power battery that has not failed supplies power to the load 2 to drive the vehicle to a repair station or a safe location, preventing the vehicle from stopping suddenly and improving driving safety.

[0030] In one example, the bidirectional converter 1 may include a power interface and a signal interface. The power interface is used to connect to an external power supply to power the circuitry of the bidirectional converter 1, and the signal interface is used to receive control signals. In response to the received control signals, the bidirectional converter 1 switches the connectivity of each terminal.

[0031] For example, such as Figure 1 As shown, load 2 may include a drive motor.

[0032] This application provides a high-voltage circuit including: a first power battery B1, a second power battery B2, and a bidirectional converter 1; the first terminal of the first power battery B1 is connected to the first terminal a of the bidirectional converter 1, and the second terminal of the first power battery B1 is connected to the first terminal of a load 2; the first terminal of the second power battery B2 is connected to the second terminal of the load 2, and the second terminal of the second power battery B2 is connected to the third terminal c of the bidirectional converter 1; the second terminal b of the bidirectional converter 1 is connected to a first connection point m, and the fourth terminal d of the bidirectional converter 1 is connected to a second connection point n; the first connection point m is the connection point between the first terminal of the second power battery B2 and the load 2, and the second connection point n is the connection point between the second terminal of the first power battery B1 and the load 2; the bidirectional converter 1 is configured such that: under normal operating conditions, the first terminal a and the third terminal c of the bidirectional converter 1 are connected; under fault operating conditions, the first terminal a and the second terminal b of the bidirectional converter 1 are connected, and the third terminal c and the fourth terminal d of the bidirectional converter 1 are connected. With this configuration, this application utilizes a bidirectional converter 1 to switch between the series and parallel connection of the first power battery B1 and the second power battery B2. When neither power battery is faulty, i.e., under normal operating conditions, the first terminal a and the third terminal c of the bidirectional converter 1 are connected, making the first power battery B1 and the second power battery B2 connected in series, and both supply power to the load 2. When one of the two power batteries is faulty, i.e., under fault conditions, the first terminal a and the second terminal b of the bidirectional converter 1 and the third terminal c and the fourth terminal d of the bidirectional converter 1 are connected, making the first power battery B1 and the second power battery B2 connected in parallel. The power battery that is not faulty supplies power to the load 2 to drive the vehicle to a repair station or a safe location, preventing the vehicle from stopping suddenly and improving driving safety.

[0033] In one embodiment, the bidirectional converter can also be configured to: disconnect the connection between the terminals of the bidirectional converter or connect the first terminal and the third terminal of the bidirectional converter when the power is off.

[0034] In this embodiment, when the vehicle is not working, i.e. in the power-off state, the first and second terminals of the bidirectional converter are connected to connect the first and second power batteries in series, or the connection between each terminal of the bidirectional converter is disconnected to prevent the load 2 from being connected to the positive or negative terminal of the power battery when the power is off, which helps to reduce safety risks.

[0035] In one embodiment, such as Figure 2 As shown, the high-voltage circuit may also include: a first switch K1 and a second switch K2.

[0036] The first switch K1 is located on the branch between the first power battery B1 and the second connection point n; the second switch K2 is located on the branch between the second power battery B2 and the first connection point m.

[0037] The first switch K1 and the second switch K2 may include all types of electronic devices with switching functions known to those skilled in the art, such as relays, contactors or single-pole switches, without limitation herein.

[0038] For example, such as Figure 2 As shown, the first switch K1 and the second switch K2 can be relays. The first switch K1 is connected to the negative terminal of the first power battery B1, and can also be named "main negative relay"; the second switch is connected to the positive terminal of the second power battery B2, and can also be named "main positive relay".

[0039] When the first power battery B1 and the second power battery B2 are connected in series, the first switch K1 and the second switch K2 are closed to connect the power batteries and the load 2, and the first power battery B1 and the second power battery B2 supply power to the load.

[0040] When the first power battery B1 and the second power battery B2 are connected in parallel, if neither power battery malfunctions, the first switch K1 and the second switch K2 are closed, connecting the power batteries to the load 2. The first power battery B1 and the second power battery B2 supply power to the load, and the supply voltage at this time is less than the supply voltage of the first power battery B1 and the second power battery B2 connected in series. If the first power battery B1 malfunctions, the second switch K2 is closed and the first switch K1 is opened, connecting the second power battery B2 to the load 2, and the second power battery B2 supplies power to the load 2. If the second power battery B2 malfunctions, the first switch K1 is closed and the second switch K2 is opened, connecting the first power battery B1 to the load 2, and the first power battery B1 supplies power to the load 2.

[0041] In this embodiment, the first switch K1 and the second switch K2 can connect the power battery and the load 2 when the vehicle is working, so that the power battery supplies power to the load 2, and disconnect the connection between the power battery and the load 2 when the vehicle is powered off, so as to precisely control the "on" and "off" of the high voltage circuit; at the same time, when the vehicle malfunctions (such as stalling, overcurrent or leakage), the first switch K1 and the second switch K2 are disconnected to cut off the high voltage circuit, so as to avoid high voltage leakage or component damage and protect the safety of personnel and equipment.

[0042] In one embodiment, such as Figure 3 As shown, the high-voltage circuit also includes: a first pre-charge module 91, a second pre-charge module 92, and a first capacitor 31.

[0043] The first pre-charge module 91 is disposed on the branch between the first power battery B1 and the load 2, and is connected in parallel with the first switch K1. The second pre-charge module 92 is disposed on the branch between the second power battery B2 and the load 2, and is connected in parallel with the second switch K2. The first terminal of the first capacitor 31 is connected to the first terminal of the load 2, and the second terminal of the first capacitor 31 is connected to the second terminal of the load 2, that is, the first capacitor 31 is connected in parallel with the load 2.

[0044] In this embodiment, when the high-voltage circuit is powered on, one of the first pre-charge module 91 and the second pre-charge module 92 is used to gradually charge the first capacitor 31, so that the voltage of the first capacitor 31 gradually increases. This avoids the surge current impact caused by directly connecting the power battery, which helps to protect the components in the circuit, prevents damage to them by large current, and extends the service life of the equipment.

[0045] In one embodiment, such as Figure 5 As shown, the first pre-charge module may include a first pre-charge switch K6 and a first pre-charge resistor R1. One end of the first pre-charge resistor R1 is connected to the second terminal of the first power battery B1 and the first terminal of the first switch K1, respectively. The other end of the first pre-charge resistor R1 is connected to the first terminal of the first pre-charge switch K6. The second terminal of the first pre-charge switch K6 is connected to the second terminal of the first switch K1 and the first terminal of the load 2, respectively. The first pre-charge switch K6 and the first pre-charge resistor R1 are connected in series, and the first pre-charge module formed by them is connected in parallel with the first switch K1.

[0046] The second pre-charge module includes a second pre-charge switch K7 and a second pre-charge resistor R2. One end of the second pre-charge resistor R2 is connected to the first terminal of the second power battery B2 and the first terminal of the second switch K2, respectively. The other end of the second pre-charge resistor R2 is connected to the first terminal of the second pre-charge switch K7. The second terminal of the second pre-charge switch K7 is connected to the second terminal of the second switch K2 and the second terminal of the load 2, respectively. The second pre-charge switch K7 and the second pre-charge resistor R2 are connected in series, and the second pre-charge module formed by them is connected in parallel with the second switch K2.

[0047] For example, such as Figure 5 As shown, the vehicle load is an 800V high-voltage platform component, connecting the first terminal a and the third terminal c of the bidirectional converter 1, so that the first power battery B1 and the second power battery B2 are connected in series. When the high-voltage circuit is powered on, the first pre-charge switch K6 and the second switch K2 are closed (or the second pre-charge switch K7 and the first switch K1 are closed), and the second pre-charge resistor R2 (or the first pre-charge group R1) gradually charges the first capacitor 31, so that the voltage of the first capacitor 31 gradually rises. When the voltage of the first capacitor 31 reaches the set threshold (close to the voltage of the power battery), the pre-charge is completed, the first switch K1 (or the second switch K2) is closed, and the first pre-charge switch K6 (or the second pre-charge switch K7) is opened, and the high-voltage circuit is completed.

[0048] For example, such as Figure 5 As shown, when the first power battery B1 fails, the first terminal a and the second terminal b of the bidirectional converter 1 are connected, as well as the third terminal c and the fourth terminal d of the bidirectional converter 1, so that the first power battery B1 and the second power battery B2 are connected in parallel. When the high-voltage circuit is powered on, the second pre-charge switch K7 is closed, and the first switch K1, the second switch K2 and the first pre-charge switch K6 are opened. The second pre-charge resistor R2 gradually charges the first capacitor 31, so that the voltage of the first capacitor 31 gradually rises. When the voltage of the first capacitor 31 reaches the set threshold (close to the voltage of the power battery), the pre-charge is completed. The second switch K2 is closed, the second pre-charge switch K7 is opened, and the high-voltage circuit is powered on.

[0049] For example, such as Figure 5 As shown, when the second power battery B2 fails, the first terminal a and the second terminal b of the bidirectional converter 1 are connected, as well as the third terminal c and the fourth terminal d of the bidirectional converter 1, so that the first power battery B1 and the second power battery B2 are connected in parallel. When the high-voltage circuit is powered on, the first pre-charge switch K6 is closed, and the first switch K1, the second switch K2 and the second pre-charge switch K7 are opened. The first pre-charge resistor R1 gradually charges the first capacitor 31, so that the voltage of the first capacitor 31 gradually rises. When the voltage of the first capacitor 31 reaches the set threshold (close to the voltage of the power battery), the pre-charge is completed. The first switch K1 is closed, the first pre-charge switch K6 is opened, and the high-voltage circuit is powered on.

[0050] This embodiment uses a pre-charge switch and a pre-charge resistor to pre-charge the high-voltage circuit, avoiding the surge current impact caused by directly connecting the power battery. This helps protect the components in the circuit, prevents damage from large currents, and extends the service life of the equipment.

[0051] In one embodiment, such as Figure 4 As shown, the high-voltage circuit also includes: a reverse pre-charged DC-DC converter 42 and a second capacitor 32.

[0052] In this configuration, the first terminal of the reverse pre-charge DC-DC converter 42 is connected to the first terminal of the load 2, the second terminal of the reverse pre-charge DC-DC converter 42 is connected to the second terminal of the load 2, and the third terminal of the reverse pre-charge DC-DC converter 42 is connected to the DC power supply 5. The first terminal of the second capacitor 32 is connected to the first terminal of the load 2, and the second terminal of the second capacitor 32 is connected to the second terminal of the load 2. Both the second capacitor 32 and the reverse pre-charge DC-DC converter 42 are connected in parallel with the load 2.

[0053] The reverse pre-charge DC-DC converter 42 has bidirectional conversion functionality. In reverse pre-charge mode, electrical energy is pre-charged from the low-voltage side (i.e., DC power supply 5) to the equivalent capacitance of the electrical equipment on the high-voltage side (i.e., the second capacitor 32), inverting the low-voltage electricity into high-voltage electricity to pre-charge the high-voltage circuit. The reverse pre-charge DC-DC converter 42 also has a forward power supply mode, which can convert the high-voltage electricity from the power battery into low-voltage electricity to charge the DC power supply 5. In one example, the DC power supply 5 may include a 12V / 48V lithium battery.

[0054] compared to Figure 3 The DC-DC converter 41 in this embodiment does not have a reverse pre-charge function. Instead, it performs pre-charge by reusing the reverse pre-charge type DC-DC converter 42 in the high-voltage circuit. This eliminates the need for a pre-charge module, reduces the number of electronic components, and helps to reduce costs. At the same time, the reverse pre-charge type DC-DC converter 42 has both forward power supply and reverse pre-charge functions, which improves flexibility and compatibility.

[0055] In one embodiment, such as Figures 3-5 As shown in any figure, the high-voltage circuit also includes a third switch K3, which is located on the branch between the first switch K1 and the first end of the charging interface 6.

[0056] In this embodiment, the second switch K2 is connected to the second end of the charging interface 6. During charging, the third switch K3 is closed to connect the power battery to the charging interface, forming a charging circuit. An external power source (such as a charging pile) can charge the first power battery B1 and the second power battery B2. When charging is not needed or in case of an abnormal situation, the third switch K3 is opened to cut off the charging circuit and prevent unnecessary current flow.

[0057] In one embodiment, such as Figures 3-5 As shown in any figure, the high-voltage circuit also includes a fourth switch K4, which is located on the branch between the second switch K2 and the second end of the charging interface 6.

[0058] In this embodiment, the first switch K1 is connected to the first end of the charging interface 6. During charging, the fourth switch K4 is closed to connect the power battery to the charging interface, forming a charging circuit. An external power source (such as a charging pile) can charge the first power battery B1 and the second power battery B2. When charging is not needed or in case of an abnormal situation, the fourth switch K4 is opened to cut off the charging circuit and prevent unnecessary current flow.

[0059] In one embodiment, such as Figures 3-5 As shown in any figure, the high-voltage circuit also includes a third switch K3 and a fourth switch K4. The third switch K3 is located on the branch between the first switch K1 and the first end of the charging interface 6, and the fourth switch K4 is located on the branch between the second switch K2 and the second end of the charging interface 6.

[0060] In this embodiment, during charging, the third switch K3 and the fourth switch K4 are closed to connect the power battery to the charging interface, forming a charging circuit. An external power source (such as a charging pile) can then charge the first power battery B1 and the second power battery B2. When charging is not needed or in case of an abnormal situation, the third switch K3 and the fourth switch K4 are disconnected to cut off the charging circuit and prevent unnecessary current flow.

[0061] In one implementation, such as Figure 5 As shown, the load includes an upper bridge arm module 21, a lower bridge arm module 22, and a three-phase inductor 23. The first end of the upper bridge arm module 21 is connected to the second switch K2, the second end of the upper bridge arm module 21 is connected to the first end of the lower bridge arm module 22, the second end of the lower bridge arm module 22 is connected to the first switch K1, and the connection point between the upper bridge arm module 21 and the lower bridge arm module 22 is connected to the first end of the three-phase inductor 23. The high-voltage circuit also includes a fifth switch K5, which is located on the branch between the third end c of the bidirectional converter 1 and the three-phase inductor 23.

[0062] The upper bridge arm module 21 may include three sets of upper bridge arms, each set including a power switching device and a diode connected in anti-parallel. The power switching device may include a metal-oxide-semiconductor field-effect transistor (MOSFET) and an insulated-gate bipolar transistor (IGBT). The lower bridge arm module 22 may include three sets of lower bridge arms, each set including a power switching device and a diode connected in anti-parallel. The power switching device may include a MOSFET and an IGBT. The three-phase inductor 23 may include three sets of winding coils.

[0063] For example, such as Figure 5 As shown, the upper bridge arm module 21 may include: a first power switch device V1, a second power switch device V2, a third power switch device V3, a first diode D1, a second diode D2, and a third diode D3; the lower bridge arm module 22 may include: a fourth power switch device V4, a fifth power switch device V5, a sixth power switch device V6, a fourth diode D4, a fifth diode D5, and a sixth diode D6. The upper and lower bridge arms of each phase are connected to the corresponding windings.

[0064] In this embodiment, the first terminal a and the third terminal c of the bidirectional converter 1 are connected, so that the first power battery B1 and the second power battery B2 are connected in series. The first switch K1, the second switch K2 and the fifth switch K5 control the upper bridge arm module 21 and the lower bridge arm module 22 to be turned on alternately according to a set timing sequence. The on / off state of the upper bridge arm module 21 and the on / off state of the lower bridge arm module 22 are mutually exclusive. When the lower bridge arm module 22 is in the ON state, the upper bridge arm module 21 is in the OFF state, and the first power battery B1 discharges to charge the three-phase inductor 23. When the lower bridge arm module 22 is in the OFF state, the upper bridge arm module 21 is in the ON state, and the three-phase inductor 23 discharges to charge the second power battery B2. After the charge in the three-phase inductor is depleted, the second power battery B2 discharges to charge the three-phase inductor 23. When the lower bridge arm module 22 is ON again and the upper bridge arm module 21 is OFF again, the three-phase inductor 23 discharges to charge the first power battery B1. After the charge in the three-phase inductor is depleted, the first power battery B1 discharges to charge the three-phase inductor 23. This embodiment controls the charging and discharging process of the power battery by controlling the alternating ON and OFF states of the upper and lower bridge arms, allowing electrical energy to circulate between the power battery and the three-phase inductor 23. Each energy conversion is accompanied by a certain amount of energy loss, which is released as heat, thereby increasing the temperature of the power battery. When the ambient temperature is low, the temperature of the power battery is also low. Before charging or supplying power, the power battery is subjected to low-frequency self-heating in the above manner. By utilizing the energy storage characteristics of the three-phase inductor 23, a pulse current is generated, causing the first power battery B1 to discharge to the second power battery B2. Then, the second power battery B2 discharges to the first power battery B1 in the reverse direction. This cycle is repeated to raise the temperature of the power battery to a suitable temperature range, which is beneficial to improving the conductivity of the electrolyte and increasing the charging and discharging efficiency.

[0065] In one embodiment, such as Figure 4 and Figure 5 As shown, the high-voltage circuit also includes: a current collector 7, which is disposed at least at one of the following branches: the branch between the negative terminal of the first power battery B1 and the first switch K1, the branch between the second connection point n and the load, and the branch between the third terminal c of the bidirectional converter 1 and the second power battery B2.

[0066] The current acquisition device 7 includes all electronic devices with current acquisition functions known to those skilled in the art, such as current sensors or shunts, which are not limited herein.

[0067] When the first power battery B1 and the second power battery B2 are connected in series, the current collector 7 located in the branch between the negative terminal of the first power battery B1 and the first switch K1, the current collector 7 located in the branch between the second connection point n and the load, and the current collector 7 located in the branch between the third terminal c of the bidirectional converter 1 and the second power battery B2, all collect the current values ​​of the series circuit, and the current values ​​are equal. Multiple current collectors 7 can operate simultaneously, which meets the functional safety ASILC requirements.

[0068] When the first power battery B1 and the second power battery B2 are connected in parallel, the current collector 7 located in the branch between the negative terminal of the first power battery B1 and the first switch K1 is used to collect the current value of the parallel circuit in which the first power battery B1 is located; the current collector 7 located in the branch between the third terminal c of the bidirectional converter 1 and the second power battery B2 is used to collect the current value of the parallel circuit in which the second power battery B2 is located; and the current collector 7 located in the branch between the second connection point n and the load is used to collect the current value after the two parallel circuits are combined.

[0069] In one embodiment, such as Figures 3-5 As shown in any figure, the high-voltage circuit also includes: a first protection module 81 and a second protection module 82.

[0070] The first protection module 81 is disposed on the branch between the positive terminal of the first power battery B1 and the bidirectional converter 1. The second protection module 82 is disposed on the branch between the positive terminal of the second power battery B2 and the second switch K2. The first protection module 81 and the second protection module 82 may include all electronic devices with electrical protection functions known to those skilled in the art, such as fuses, smart fuses and circuit breakers, which are not limited herein.

[0071] In this embodiment, the first protection module 81 is connected in series with the first power battery B1, and the second protection module 82 is connected in series with the second power battery B2. By associating them with the corresponding sensors, protection against overcurrent, overvoltage, or overtemperature in the high-voltage circuit can be achieved.

[0072] For example, the first protection module 81 and the second protection module 82 are smart fuses. The first protection module 81 is connected to the positive terminal of the first power battery B1, and the second protection module 82 is connected to the positive terminal of the second power battery B2. When the circuit is overloaded / short-circuited and the fuse blows, the connection between the positive terminal and the subsequent circuit (such as the load or wiring harness) will be completely cut off. There will be no voltage in the subsequent circuit, and there will be no risk of electric shock during maintenance or handling.

[0073] For example, such as Figure 4As shown, the first protection module 81 and the current collector 7 located in the branch between the negative terminal of the first power battery B1 and the first switch K1 realize overcurrent protection for the first power battery B1; the second protection module 82 and the current collector 7 located in the branch between the third terminal c of the bidirectional converter 1 and the second power battery B2 realize overcurrent protection for the second power battery B2.

[0074] For example, such as Figure 6 As shown, the vehicle load is an 800V high-voltage platform component, connecting the first terminal a and the third terminal c of the bidirectional converter 1, so that the first power battery B1 and the second power battery B2 are connected in series. First, the second pre-charge switch K7 (or the first pre-charge switch K6) is closed, then the first switch K1 (or the second switch K2) is closed. After pre-charging is completed, the second switch K2 (or the first switch K1) is closed, and the second pre-charge switch K7 (or the first pre-charge switch K6) is opened. The high-voltage circuit completes the high-voltage connection, and the first power battery B1 and the second power battery B2 supply power to the load in series mode. The current flow path is as follows. Figure 6 As shown.

[0075] For example, such as Figure 7 As shown, if the first power battery B1 malfunctions before high voltage is applied, and single-branch discharge mode is permitted, then the first terminal a and the second terminal b of the bidirectional converter 1 are connected, as are the third terminal c and the fourth terminal d of the bidirectional converter 1, making the first power battery B1 and the second power battery B2 connected in parallel. The second pre-charge switch K7 is closed. After pre-charging is completed, the second switch K2 is closed, the second pre-charge switch K7 is opened, and the first switch K1 is not closed, thus completing the high voltage application. The second power battery B2 supplies power to the load, and the current flow path is as follows. Figure 7 As shown.

[0076] For example, such as Figure 8 As shown, if the second power battery B2 malfunctions before high voltage is applied, and single-branch discharge mode is permitted, then the first terminal a and the second terminal b of the bidirectional converter 1 are connected, as are the third terminal c and the fourth terminal d of the bidirectional converter 1, so that the first power battery B1 and the second power battery B2 are connected in parallel. The first pre-charge switch K6 is closed. After pre-charging is completed, the first switch K1 is closed, the first pre-charge switch K6 is opened, and the second switch K2 is not closed, thus completing the high voltage application. The first power battery B1 supplies power to the load, and the current flow path is as follows. Figure 8 As shown.

[0077] For example, such as Figure 9As shown, when the maximum output voltage of the charging device (e.g., a charging pile) is greater than or equal to a set voltage threshold, the series charging condition is met. The first terminal a and the third terminal c of the bidirectional converter 1 are connected, connecting the first power battery B1 and the second power battery B2 in series. First, the second pre-charge switch K7 (or the first pre-charge switch K6) is closed, then the first switch K1 (or the second switch K2) is closed. After pre-charging is complete, the second switch K2 (or the first switch K1) is closed, and the second pre-charge switch K7 (or the first pre-charge switch K6) is opened. The high-voltage circuit completes the high-voltage connection. The third switch K3 and the fourth switch K4 are closed, the charging circuit is connected, and the charging device performs series charging of the first power battery B1 and the second power battery B2. The charging current flow path is as follows: Figure 9 As shown.

[0078] For example, such as Figure 10 As shown, if the first power battery B1 malfunctions before charging, and single-branch charging mode is permitted, then the first terminal a and the second terminal b of the bidirectional converter 1 are connected, as are the third terminal c and the fourth terminal d of the bidirectional converter 1, so that the first power battery B1 and the second power battery B2 are connected in parallel. The second pre-charge switch K7 is closed. After pre-charging is completed, the second switch K2 is closed, the second pre-charge switch K7 is opened, and the first switch K1 is not closed, thus completing the high voltage connection. The third switch K3 and the fourth switch K4 are closed, the charging circuit is connected, and the charging device charges the second power battery B2. The charging current flow path is as follows. Figure 10 As shown.

[0079] For example, such as Figure 11 As shown, if the second power battery B2 malfunctions before charging, and single-branch charging mode is permitted, then the first terminal a and the second terminal b of the bidirectional converter 1 are connected, as are the third terminal c and the fourth terminal d of the bidirectional converter 1, so that the first power battery B1 and the second power battery B2 are connected in parallel. The first pre-charge switch K6 is closed. After pre-charging is completed, the first switch K1 is closed, the first pre-charge switch K6 is opened, the second switch K2 is not closed, high voltage is applied, the third switch K3 and the fourth switch K4 are closed, the charging circuit is connected, and the charging device charges the first power battery B1. The charging current flow path is as follows. Figure 11 As shown.

[0080] For example, such as Figure 12As shown, if the battery is in a normal low-voltage state before charging, the first terminal a and the second terminal b of the bidirectional converter 1 are connected, as are the third terminal c and the fourth terminal d of the bidirectional converter 1, so that the first power battery B1 and the second power battery B2 are connected in parallel. The first pre-charge switch K6 and / or the second pre-charge switch K7 are closed. After pre-charging is completed, the first switch K1 and the second switch K2 are closed, and the pre-charge switches are opened. If the voltage difference between the first power battery B1 and the second power battery B2 is large, the first pre-charge switch K6 can be closed first. After the loop current drops to the allowable value, the second switch K2 can be closed. After the high voltage is completed, the third switch K3 and the fourth switch K4 are closed, the charging circuit is connected, and the charging device charges the first power battery B1 and the second power battery B2 in parallel. The charging current flow path is as follows. Figure 12 As shown. If the battery is in series high-voltage shutdown mode before charging, the load current needs to be reduced, the first switch K1 and the second switch K2 need to be disconnected, the first terminal a and the second terminal b of the bidirectional converter 1 need to be connected, and the third terminal c and the fourth terminal d of the bidirectional converter 1 need to be connected, so that the first power battery B1 and the second power battery B2 are connected in parallel, and then the above steps are performed. At the end of the parallel charging of the first power battery B1 and the second power battery B2, when one of the first power battery B1 and the second power battery B2 is fully charged, if the voltage difference between the first power battery B1 and the second power battery B2 exceeds a certain value, the switch (first switch K1 or second switch K2) connected to the lower voltage power battery can be disconnected, and the lower voltage power battery can be fully charged separately. During the parallel charging process, the flow path of the charging current is as follows. Figure 12 As shown.

[0081] For example, such as Figure 13 As shown, the bidirectional converter is in series mode by default, that is, the first terminal a and the third terminal c of the bidirectional converter 1 are connected, the first switch K1 and the second switch K2 are closed, and then the fifth switch K5 is closed; in the first stage of low-frequency self-heating, the lower bridge arm module 22 is turned on, the upper bridge arm module 21 is turned off, the three-phase inductor 23 is charged, and the first power battery B1 is discharged. The current flow path is as follows. Figure 13 As shown. In the second stage of low-frequency self-heating, the lower bridge arm module 22 is disconnected, the upper bridge arm module 21 is turned on, the three-phase inductor 23 discharges, and the second power battery B2 is charged. The current flow path is as follows. Figure 14 As shown. In the third stage, the lower bridge arm module 22 is disconnected and the upper bridge arm module 21 is turned on. After the three-phase inductor 23 is depleted, the second power battery B2 discharges and the three-phase inductor 23 is charged. In the fourth stage, the lower bridge arm module 22 is turned on and the upper bridge arm module 21 is disconnected. The three-phase inductor 23 discharges and the first power battery B1 is charged. The above four stages are executed in a cycle.

[0082] The low-frequency self-heating process is achieved by controlling the current according to... Figure 15The trend shown in the diagram above causes the upper arm module and the lower arm module to follow... Figure 15 The timing control shown alternates between turning on and off, utilizing the energy storage characteristics of the three-phase inductor 23 to generate a pulse current, causing the first power battery B1 to discharge to the second power battery B2, and then the second power battery B2 to discharge to the first power battery B1 in reverse, and so on, to raise the temperature of the power battery to a suitable temperature range, which is beneficial to improving the conductivity of the electrolyte and improving the charging and discharging efficiency.

[0083] Based on the high-voltage circuit provided in the above embodiments, this application also provides a vehicle. The vehicle includes any of the above-described high-voltage circuits, each with corresponding beneficial effects; to avoid repetition, these will not be elaborated upon here.

[0084] The vehicles may include pure electric vehicles or hybrid vehicles, and are not limited to these.

[0085] In other embodiments, the vehicle may also include all components known to those skilled in the art, such as a vehicle controller and a battery management system, which are not limited herein.

[0086] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A high-voltage circuit, characterized in that, include: First power battery, second power battery, and bidirectional converter; Wherein, the first terminal of the first power battery is connected to the first end of the bidirectional converter, and the second terminal of the first power battery is connected to the first end of the load; the first terminal of the second power battery is connected to the second end of the load, and the second terminal of the second power battery is connected to the third end of the bidirectional converter; the second end of the bidirectional converter is connected to a first connection point, and the fourth end of the bidirectional converter is connected to a second connection point; the first connection point is the connection point between the first terminal of the second power battery and the load, and the second connection point is the connection point between the second terminal of the first power battery and the load; The bidirectional converter is configured such that, under normal operating conditions, the first and third terminals of the bidirectional converter are connected; and under fault conditions, the first and second terminals of the bidirectional converter, and the third and fourth terminals of the bidirectional converter are connected.

2. The high-voltage circuit according to claim 1, characterized in that, Also includes: First switch; The first switch is located on the branch between the first power battery and the second connection point; Second switch; The second switch is located on the branch between the second power battery and the first connection point.

3. The high-voltage circuit according to claim 2, characterized in that, Also includes: First pre-charge module; The first pre-charge module is disposed on the branch between the first power battery and the load, and the first pre-charge module is connected in parallel with the first switch; The second pre-charge module is disposed on the branch between the second power battery and the load, and the second pre-charge module is connected in parallel with the second switch. A first capacitor; a first terminal of the first capacitor is connected to a first terminal of the load, and a second terminal of the first capacitor is connected to a second terminal of the load.

4. The high-voltage circuit according to claim 3, characterized in that, The first pre-charge module includes a first pre-charge switch and a first pre-charge resistor. One end of the first pre-charge resistor is connected to the second terminal of the first power battery and the first terminal of the first switch, respectively. The other end of the first pre-charge resistor is connected to the first terminal of the first pre-charge switch. The second terminal of the first pre-charge switch is connected to the second terminal of the first switch and the first terminal of the load, respectively. The second precharge module includes a second precharge switch and a second precharge resistor. One end of the second precharge resistor is connected to the first terminal of the second power battery and the first terminal of the second switch, respectively. The other end of the second precharge resistor is connected to the first terminal of the second precharge switch, and the second terminal of the second precharge switch is connected to the second terminal of the second switch and the second terminal of the load, respectively.

5. The high-voltage circuit according to claim 2, characterized in that, Also includes: A reverse precharge DC-DC converter, wherein a first terminal of the reverse precharge DC-DC converter is connected to a first terminal of the load, a second terminal of the reverse precharge DC-DC converter is connected to a second terminal of the load, and a third terminal of the reverse precharge DC-DC converter is connected to a DC power supply. The second capacitor; the first terminal of the second capacitor is connected to the first terminal of the load, and the second terminal of the second capacitor is connected to the second terminal of the load.

6. The high-voltage circuit according to claim 5, characterized in that, Also includes: The third switch is disposed on the branch between the first switch and the first end of the charging interface; And / or, a fourth switch, which is disposed on a branch between the second switch and the second end of the charging interface.

7. The high-voltage circuit according to claim 2, characterized in that, The load includes an upper bridge arm module, a lower bridge arm module, and a three-phase inductor. The first end of the upper bridge arm module is connected to the second switch, the second end of the upper bridge arm module is connected to the first end of the lower bridge arm module, the second end of the lower bridge arm module is connected to the first switch, and the connection point between the upper bridge arm module and the lower bridge arm module is connected to the first end of the three-phase inductor. The high-voltage circuit also includes a fifth switch, which is located on the branch between the third terminal of the bidirectional converter and the three-phase inductor.

8. The high-voltage circuit according to claim 2, characterized in that, Also includes: The first protection module is disposed on the branch between the positive terminal of the first power battery and the bidirectional converter; The second protection module is located on the branch between the positive terminal of the second power battery and the second switch.

9. The high-voltage circuit according to claim 2, characterized in that, Also includes: A current collector is disposed at at least one of the following: the branch between the negative terminal of the first power battery and the first switch; the branch between the second connection point and the load; and the branch between the third terminal of the bidirectional converter and the second power battery.

10. A vehicle, characterized in that, include: The high-voltage circuit as described in any one of claims 1-9.

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