Vehicle power supply system, vehicle power supply method, and electric vehicle for electric vehicle

Abstract

The embodiment of the present specification provides a vehicle power supply system, a vehicle power supply method and an electric vehicle. The vehicle power supply system comprises a power battery system and a low-power DC conversion device. The battery management device in the power battery system determines the target voltage value of the low-power DC conversion device according to the battery capacity state of the first low-voltage battery component in the vehicle low-voltage system, thereby controlling the low-power DC conversion device to convert the high-voltage power provided by the high-voltage battery component into low-voltage power with the target voltage value, and providing the converted low-voltage power to the vehicle auxiliary equipment in the vehicle low-voltage system for low-voltage power supply. According to this vehicle low-voltage power supply mode, the low-voltage power supply capability and efficiency of the electric vehicle can be improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present specification generally relate to the field of electric vehicles, and in particular, to a vehicle power supply system for an electric vehicle, a vehicle power supply method, and an electric vehicle. BACKGROUND

[0002] With the development of electric vehicle technology, the functions supported by electric vehicles are becoming more and more rich, such as sentry mode, refrigerator, etc., and the size of the display screen is also getting larger and larger, thereby causing the low-voltage power consumption of the low-voltage system in the electric vehicle (e.g., vehicle auxiliary equipment, etc.) to rapidly increase. How to improve the low-voltage power supply capability and efficiency of the electric vehicle is an urgent demand in the field of electric vehicles. SUMMARY

[0003] Embodiments of the present specification provide a vehicle power supply system for an electric vehicle and an electric vehicle. With the vehicle power supply system, the low-voltage power supply capability and efficiency of the electric vehicle can be improved.

[0004] According to an aspect of embodiments of the present specification, a vehicle power supply system for an electric vehicle is provided, comprising: a power battery system, the power battery system comprising a high-voltage battery assembly and a battery management device; and a low-power direct current conversion device configured to convert high-voltage power provided by the high-voltage battery assembly into low-voltage power, and provide the converted low-voltage power to a low-voltage system for low-voltage power supply, wherein the battery management device is configured to control a direct current conversion process of the low-power direct current conversion device according to a battery state of charge of a first low-voltage battery assembly in the low-voltage system.

[0005] Optionally, in one example of the above aspect, the battery management device is configured to: determine a target voltage value of the low-power direct current conversion device according to the battery state of charge of the first low-voltage battery assembly and the operating state information of the low-voltage load; and control the low-power direct current conversion device to convert the high-voltage into low-voltage with the target voltage value.

[0006] Optionally, in one example of the above aspect, the vehicle low-voltage system further comprises a charging selection unit disposed between the first low-voltage battery assembly and the low-power DC conversion device, the charging selection unit being configured to select whether to charge the first low-voltage battery assembly by the low-power DC conversion device based on the target voltage value. The battery management device is configured to: when the battery state of charge of the first low-voltage battery assembly indicates that the battery charge is not lower than the nominal operating charge of the first low-voltage battery assembly, determine the target voltage value such that the low-power DC conversion device does not charge the first low-voltage battery assembly during power supply to the low-voltage load in the vehicle low-voltage system; and when the battery state of charge of the first low-voltage battery assembly indicates that the battery charge is lower than the nominal operating charge of the first low-voltage battery assembly, determine the target voltage value such that the low-power DC conversion device charges the first low-voltage battery assembly during power supply to the low-voltage load in the vehicle low-voltage system.

[0007] Optionally, in one example of the above aspect, the battery management device is configured to determine the target voltage value of the low-power DC conversion device according to the battery state of charge of the first low-voltage battery assembly and the power consumption information of the low-voltage load in the vehicle low-voltage system.

[0008] Optionally, in one example of the above aspect, the battery management device is configured to determine a target current value of the low-power DC conversion device according to an operating current value of the low-voltage load in the vehicle low-voltage system; and control the low-power DC conversion device to convert the high-voltage electricity into low-voltage electricity with the target voltage value and the target current value after the high-voltage electricity is converted into low-voltage electricity with the target voltage value.

[0009] Optionally, in one example of the above aspect, the power battery system further comprises a cell module controller configured to obtain high-voltage battery state information of the high-voltage battery assembly. Accordingly, the battery management device is configured to control the low-power DC conversion device not to perform DC conversion in response to the high-voltage battery state information indicating that the high-voltage battery assembly is abnormal.

[0010] Optionally, in one example of the above aspect, the vehicle power supply system further comprises a second low-voltage battery assembly. The battery management device is configured to be powered by the second low-voltage battery assembly when the low-power DC conversion device is in a non-operating state, and to be powered by the low-power DC conversion device when the low-power DC conversion device is in an operating state.

[0011] Optionally, in one example of the above aspect, the power terminal of the battery management device is connected with the output power terminal of the low-power DC conversion device, and is connected with the power terminal of the second low-voltage battery assembly via a second switching device, the second switching device being configured to be closed when the low-power DC conversion device is in a non-working state, and to be opened when the low-power DC conversion device is in a working state.

[0012] Optionally, in one example of the above aspect, the output power terminal of the low-power DC conversion device is connected with the power terminal of the battery management device via a reverse connection protection assembly.

[0013] Optionally, in one example of the above aspect, the input power terminal of the low-power DC conversion device is connected with the power terminal of the high-voltage battery assembly via an overcurrent and short-circuit protection device.

[0014] Optionally, in one example of the above aspect, the low-power DC conversion device is built-in in the power battery system.

[0015] According to another aspect of the embodiments of the present specification, a method for vehicle power supply of an electric vehicle is provided, comprising: obtaining a battery state of charge of a first low-voltage battery assembly in a vehicle low-voltage system; determining a target voltage value of a low-power DC conversion device according to the battery state of charge of the first low-voltage battery assembly; and controlling the low-power DC conversion device to convert high-voltage electricity provided by a high-voltage battery assembly in a power battery system into low-voltage electricity with the target voltage value, to provide low-voltage power supply to the vehicle low-voltage system.

[0016] According to another aspect of the embodiments of the present specification, an electric vehicle is provided, comprising a vehicle power supply system for an electric vehicle as described above. BRIEF DESCRIPTION OF DRAWINGS

[0017] Further understanding of the nature and advantages of the present specification can be realized by referring to the following drawings. In the drawings, similar components or features can have the same reference label.

[0018] Figure 1 An example block schematic diagram of a vehicle power supply system according to an embodiment of the present specification is shown.

[0019] Figure 2 An example flowchart of a vehicle power supply method according to an embodiment of the present specification is shown.

[0020] Figure 3 An example schematic diagram of a working mode switching process of a low-power DC conversion device according to an embodiment of the present specification is shown.

[0021] Figure 4An implementation example block diagram of a vehicle power supply system according to an embodiment of the present specification is shown.

[0022] Figure 5 Another implementation example schematic diagram of a vehicle power supply system according to an embodiment of the present specification is shown.

[0023] Figure 6 An example block schematic diagram of a battery management device according to an embodiment of the present specification is shown.

[0024] Figure 7 An example schematic diagram of a battery management device implemented based on a computer system according to an embodiment of the present specification is shown. DETAILED DESCRIPTION

[0025] The subject matter described herein will now be discussed with reference to example implementations. It should be understood that these implementations are discussed solely for the purpose of enabling those with ordinary skill in the art to better understand and thus, possibly utilize the subject matter described herein, and are not limitations on the scope, applicability, or examples set forth in the claims. Changes in the function and arrangement of elements discussed can be made without departing from the scope of the subject matter described herein. Various examples can omit, substitute, or add various procedures or components as appropriate. For instance, the methods described can be performed in an order different than that described, and / or various steps can be added, omitted, or combined. Also, features described with respect to some examples can be combined in other examples.

[0026] As used herein, the terms "includes" and "including" mean, and are used in the open- ended sense, that "including, but not limited to." The term "based on" means "based, at least in part, on." The terms "one embodiment" and "an embodiment" mean "at least one embodiment." The term "another embodiment" means "at least one additional embodiment." The terms "a first," "a second," etc. do not require, unless otherwise specified, that the first, second, etc. objects be different. The following detailed description is presented in terms of some embodiments. It should be understood, however, that these descriptions are not intended to limit the scope of the claims, applicability, or examples. Functional and arranging modifications as are within the scope of the present specification can be made by persons of ordinary skill in the art without departing from the scope of the present specification.

[0027] The flow diagrams in the present specification illustrate operations according to some embodiments of the present specification. It will be understood that each operation can be implemented by various means, such as hardware, software, or a combination of both. In some embodiments, the operations are implemented by one or more processors executing a computer program. In some embodiments, the operations are implemented by a computer system that is in communication with one or more processors located in one or more other devices. In some embodiments, the operations are implemented by a combination of one or more processors and one or more computer systems.

[0028] In addition to various high-voltage equipment, an electric vehicle also has many low-voltage equipment, such as a vehicle controller for controlling the behavior of the vehicle, a battery management system (BMS), an instrument panel used by the driver, a sound equipment, and the like. With the increasing richness of the functions supported by the electric vehicle, there are more and more low-voltage equipment, and the size of the display screen of the equipment is increasing, thereby rapidly increasing the low-voltage power consumption of the electric vehicle, and thus the power supply and energy supplement for the low-voltage system of the vehicle are needed.

[0029] A power supply and energy supplement scheme for a low-voltage system of a vehicle is to use a vehicle-end DC / DC device to supply power and supplement energy for the low-voltage system of the vehicle. The vehicle-end DC / DC device is usually configured to supply power to all low-voltage equipment of the low-voltage system of the vehicle, thereby needing to wake up the vehicle network when the vehicle-end DC / DC device works, so that the power consumption of the vehicle-end DC / DC device is high when it works, for example, the design power of the vehicle-end DC / DC device is usually kilowatt level, thereby resulting in low working efficiency. In addition, the service life of the vehicle-end DC / DC device is limited, usually less than 20,000 hours, and cannot realize long-time power supply and energy supplement.

[0030] In view of this, the embodiments of the present specification propose a vehicle power supply system for an electric vehicle. By using the vehicle power supply system, a low-power DC / DC device independent of the vehicle-end DC / DC device is arranged inside or outside the power battery system, and the DC conversion process of the low-power DC / DC device is controlled according to the battery capacity state of the low-voltage battery component and the working state information of the low-voltage load in the low-voltage system of the vehicle via the battery management device, thereby improving the low-voltage power supply capability and low-voltage power supply efficiency of the electric vehicle.

[0031] The vehicle power supply system, the vehicle power supply method, and the electric vehicle according to the embodiments of the present specification will be described below with reference to the accompanying drawings.

[0032] Figure 1 An example block schematic diagram of a vehicle power supply system 100 according to an embodiment of the present specification is shown.

[0033] As Figure 1As shown, the vehicle power supply system 100 includes a low-power DC conversion device 110, a battery management device 120, and a high-voltage battery assembly 130. The input positive power terminal and the input negative power terminal of the low-power DC conversion device 110 are connected to the positive power terminal and the negative power terminal of the high-voltage battery assembly 130, respectively, for converting high-voltage electricity output by the high-voltage battery assembly 130 into low-voltage electricity under the control of the battery management device 120. For example, the low-power DC conversion device 110 can convert high-voltage electricity of 300V-1000V into low-voltage electricity of 11V-14V. For example, the low-power DC conversion device 110 can be connected to the high-voltage battery assembly 130 in positive and negative directions through a high-voltage input unit. In some embodiments, an overcurrent and short-circuit protection device can be further arranged between the low-power DC conversion device 110 and the high-voltage battery assembly 130 to achieve overcurrent and short-circuit protection. An example of the overcurrent and short-circuit protection device can include a fuse. It is to be noted that in the present specification, the term "low-power DC conversion device" is used to refer to a DC conversion device capable of performing voltage DC conversion and consuming low power when performing DC conversion.

[0034] The high-voltage battery assembly 130 can be, for example, a high-voltage battery pack for powering an electric vehicle. The high-voltage battery assembly 130 can obtain electricity from a power grid through an on-board charger. The high-voltage battery assembly 130 can include a plurality of groups of serially connected cell modules, for example, 216 groups of cell modules, each having a positive terminal and a negative terminal.

[0035] The output positive power terminal and the output negative power terminal of the low-power DC conversion device 110 are connected to the positive power terminal and the negative power terminal of the vehicle low-voltage system 140, respectively, for providing the converted low-voltage electricity to the vehicle low-voltage system 140, thereby supplying power to low-voltage loads in the vehicle low-voltage system 140, and further enabling the low-voltage loads to work normally.

[0036] The vehicle low-voltage system 140 can include a first low-voltage battery assembly and low-voltage loads. The first low-voltage battery assembly is configured to supply power to the low-voltage loads. The first low-voltage battery assembly can be, for example, a 12V small battery. Examples of the low-voltage loads can include, but are not limited to, an entire vehicle controller (ECU or VCU), a battery management device, an instrument panel used by a driver, a sound equipment, or other vehicle auxiliary equipment, etc. Optionally, the vehicle low-voltage system 140 can further include a low-voltage battery management device (LVBMS) for performing battery management on the first low-voltage battery assembly in the vehicle low-voltage system. The positive power terminal and the negative power terminal of the first low-voltage battery assembly are connected to the positive power terminal and the negative power terminal of the low-voltage battery management device, respectively.

[0037] The low-power DC conversion device 110 and the first low-voltage battery assembly are configured to supply power in parallel to low-voltage loads in the vehicle low-voltage system. For example, the positive and negative output terminals of the low-power DC conversion device 110 can be configured to be connected to the positive and negative power terminals of the low-voltage loads in the vehicle low-voltage system, respectively, and the positive and negative power terminals of the first low-voltage battery assembly are configured to be connected to the positive and negative power terminals of the low-voltage loads in the vehicle low-voltage system, respectively.

[0038] The battery management device 120 is configured to control the DC conversion process of the low-power DC conversion device 110 according to a battery state of charge of the first low-voltage battery assembly in the vehicle low-voltage system. The battery state of charge of the first low-voltage battery assembly can be qualitatively represented or quantitatively represented. The qualitative representation of the battery state of charge can include, for example, a battery state of discharge, a nominal state of charge, and a full state of charge. The battery state of discharge is used to indicate that the output power of the battery is lower than the nominal power, the nominal state of charge is used to indicate that the output power of the battery is equal to the nominal power, and the full state of charge is used to indicate that the output power reaches the maximum output power of the battery. The quantitative representation of the battery state of charge can include, for example, the actual output power of the battery (an absolute output power value) or the percentage of the actual output power of the battery relative to the full state of charge, etc.

[0039] The battery management device 120 can perform data communication with the vehicle low-voltage system 140 to obtain the battery state of charge of the first low-voltage battery assembly from the vehicle low-voltage system 140 and determine the target voltage value of the low-power DC conversion device 110 according to the battery state of charge of the first low-voltage battery assembly. The battery state of charge of the first low-voltage battery assembly can be sensed by a sensing system inside or outside the vehicle low-voltage system 140 and transmitted to the battery management device 120 via a data communication channel, for example. In some embodiments, the battery management device 120 can perform data communication with the vehicle low-voltage system 140 via wired communication or wireless communication. For example, the battery management device 120 can perform data communication with the vehicle low-voltage system 140 based on CAN, Lin, SPI, or FlexRay.

[0040] The battery management device 120 can also perform data communication with the low-power DC conversion device 110 to provide the determined target voltage value to the low-power DC conversion device 110, so that the low-power DC conversion device 110 converts the high voltage provided by the high-voltage battery assembly into low voltage with the target voltage value. In some embodiments, the battery management device 120 can perform data communication with the low-power DC conversion device 110 via wired communication or wireless communication. For example, the battery management device 120 can perform data communication with the low-power DC conversion device 110 based on CAN, Lin, SPI, or FlexRay.

[0041] Optionally, the vehicle low voltage system 140 can further comprise a charging selection unit arranged between the first low voltage component and the low power DC conversion device. The charging selection unit is configured to select whether to charge the first low voltage component during the low power DC conversion device supplies power to the low voltage load based on the target voltage value. The charging selection unit can be implemented by a first switching device Q1 for example. The first switching device Q1 can be arranged between the positive power terminal of the first low voltage battery component and the output positive power terminal of the low power DC conversion device 110 and the positive power terminal of the low voltage load in the vehicle low voltage system, for example, to control the communication and disconnection between the first low voltage battery component and the low power DC conversion device 110 and the low voltage load in the vehicle low voltage system. Examples of the first switching device can include a mechanical switching device, a relay, a semiconductor switching device, etc. The semiconductor switching device can include a diode, a thyristor, a transistor, a MOSFET, an IGBT, etc. for example.

[0042] The battery management device 120 can also be referred to as a battery management system (BMS), and together with the high voltage battery component 130, forms a power battery system.

[0043] Figure 2 An example flowchart of a vehicle power supply method 200 according to an embodiment of the present specification is shown.

[0044] As shown in Figure 2 At 210, the battery management device 120 obtains high voltage battery state information of the high voltage battery component. The high voltage battery state information is used to indicate whether the high voltage battery component is abnormal, for example, the high voltage battery is depleted or the high voltage battery fails.

[0045] In some embodiments, the power battery system can further comprise one or more cell module controllers (CMC). When there are multiple cell module controllers, the multiple cell module controllers communicate with each other, and each cell module controller is configured to monitor high voltage battery state information of a group of cell modules. The monitored high voltage battery state information is uploaded to the battery management device 120. For example, a data communication channel can be arranged between the cell module controller and the battery management device 120, and the high voltage battery state information is uploaded to the battery management device 120 via the data communication channel.

[0046] At 220, it is determined whether the high voltage battery component is abnormal based on the high voltage battery state information.

[0047] In response to the high-voltage battery status information indicating that the high-voltage battery assembly is abnormal, the battery management device 120 controls the low-power DC conversion device 110 to not perform DC conversion, and returns to 210 to continue monitoring the high-voltage battery assembly for abnormality. For example, the battery management device 120 generates a DC conversion disable instruction or a sleep instruction for instructing the low-power DC conversion device to enter a sleep mode, and sends the DC conversion disable instruction or the sleep instruction to the low-power DC conversion device, so as to cause the low-power DC conversion device to not perform voltage output (i.e., not perform DC conversion) and enter the sleep mode.

[0048] In response to the high-voltage battery status information indicating that the high-voltage battery assembly is normal, at 230, the battery management device 120 acquires a battery power state of a first low-voltage battery assembly in the vehicle low-voltage system 140. The battery power state can be represented by an absolute power or a relative power with respect to a full power state.

[0049] At 240, the battery management device 120 determines a target voltage value of the low-power DC conversion device 110 according to the battery power state of the first low-voltage battery assembly.

[0050] In some embodiments, the vehicle low-voltage system 140 further includes a charging selection unit arranged between the first low-voltage battery assembly and the low-power DC conversion device. The charging selection unit is configured to select whether to charge the first low-voltage battery assembly by the low-power DC conversion device 110 based on the target voltage value.

[0051] When the battery power state of the first low-voltage battery assembly indicates that the battery power is not lower than a nominal working power of the first low-voltage battery assembly, the battery management device 120 can determine the target voltage value to be such that the low-power DC conversion device does not charge the first low-voltage battery assembly during power supply to the low-voltage load. When the battery power state of the first low-voltage battery assembly indicates that the battery power is lower than the nominal working power of the first low-voltage battery assembly, the battery management device 120 can determine the target voltage value to be such that the first low-voltage battery assembly is charged during power supply to the low-voltage load by the low-power DC conversion device.

[0052] For example, in the case where the charging selection unit is implemented by a switching device, when the battery power state of the first low-voltage battery assembly indicates that the battery power is not lower than the nominal working power of the first low-voltage battery assembly, assuming that the nominal working power is M volts (voltage value after voltage conversion processing) and the on-voltage of the switching device is N volts, the target voltage value can be determined to be a voltage value not exceeding M+V. When the battery power state of the first low-voltage battery assembly indicates that the battery power is lower than the nominal working power of the first low-voltage battery assembly, the target voltage value can be determined to be a voltage value exceeding M+V.

[0053] In some embodiments, the target voltage value of the low-power DC conversion device can be selected from pre-set voltage levels. The voltage levels can be determined based on the output voltage values of the low-power DC conversion device. For example, assuming that the low-power DC conversion device can output 8v, 10v, 12v and 24v, the voltage levels can be set as 8v, 10v, 12v and 24v, or set as voltage ranges of [7.5, 8.5], [9.5, 10.5], [11.5, 12.5] and [23.5, 24.5]. In this case, the target voltage value can be selected from the pre-set voltage levels based on the battery state of charge of the first low-voltage battery assembly.

[0054] In some embodiments, the power consumption information of the low-voltage load in the vehicle low-voltage system can also be acquired, and the target voltage value of the low-power DC conversion device can be determined according to the battery state of charge of the first low-voltage battery assembly and the power consumption information of the low-voltage load. For example, in the case that the power consumption of the low-voltage load is large, a larger target voltage value can be selected.

[0055] In some embodiments, the working parameters of the first low-voltage battery assembly can also be acquired, and the target voltage value of the low-power DC conversion device can be determined according to the battery state of charge of the first low-voltage battery assembly and the working parameters. For example, in the case that the low-power DC conversion device charges the first low-voltage battery assembly, the selected target voltage value needs to meet the working parameter requirements of the first low-voltage battery assembly.

[0056] After the target voltage value is determined, at 250, the battery management device 120 provides the determined target voltage value to the low-power DC conversion device 110. For example, the battery management device 120 can send the determined target voltage value to the low-power DC conversion device 110 by sending a voltage conversion control instruction to the low-power DC conversion device 110.

[0057] At 260, after receiving the target voltage value, the low-power DC conversion device 110 converts the high voltage provided by the high-voltage battery assembly into low voltage with the target voltage value, and at 270, the low-power DC conversion device 110 feeds the converted low voltage to the vehicle low-voltage system 140 to supply power to the low-voltage load.

[0058] It is to be noted that in some embodiments, the vehicle power supply method can also not include the operations of 210 and 220.

[0059] In some embodiments, the low-power DC conversion device 110 is configured to supply power to the low-voltage load in the vehicle low-voltage system 140 in parallel with the first low-voltage battery assembly, and a charging selection unit is configured between the first low-voltage battery assembly and the low-power DC conversion device 110. The charging selection unit is configured to select whether to charge the first low-voltage battery assembly by the low-power DC conversion device 110 based on the target voltage value.

[0060] In some embodiments, the charging selection unit can be implemented by a first switching device Q1. Accordingly, the output positive power terminal and the output negative power terminal of the low-power DC conversion device 110 are connected to the positive power terminal and the negative power terminal of the low-voltage load, respectively, the positive power terminal of the first low-voltage battery assembly is connected to the output positive power terminal of the low-power DC conversion device 110 and the positive power terminal of the low-voltage load via the first switching device Q1, and the negative power terminal of the first low-voltage battery assembly is connected to the negative power terminal of the low-voltage load.

[0061] In this case, if the target voltage value is selected to have a voltage difference from the current voltage of the first low-voltage battery assembly exceeding the on-voltage of the first switching device Q1, the first switching device Q1 is turned on, so that the low-power DC conversion device 110 charges the first low-voltage battery assembly during power supply to the low-voltage load. If the target voltage value is selected to have a voltage difference from the current voltage of the first low-voltage battery assembly not exceeding the on-voltage of the first switching device Q1, the first switching device Q1 is turned off, so that the low-power DC conversion device 110 does not charge the first low-voltage battery assembly during power supply to the low-voltage load.

[0062] A low-voltage battery management device can also be provided in the vehicle low-voltage system to monitor the low-voltage battery state information of the first low-voltage battery assembly and provide the low-voltage battery state information to the battery management device in the power battery system.

[0063] In some embodiments, during the DC conversion by the low-power DC conversion device 110, in addition to converting the voltage of the output low-voltage power to the target voltage value, it is also necessary to convert the current of the output low-voltage power to a target current value. In this case, it is also necessary to obtain the working current value of the low-voltage load in the vehicle low-voltage system and determine the target current value of the low-power DC conversion device according to the working current value of the low-voltage load. Then, after the high-voltage power is converted to low-voltage power with the target voltage value, the low-power DC conversion device is controlled to convert the high-voltage power to low-voltage power with the target voltage value and the target current value. In other words, the current conversion is performed while ensuring the target voltage value.

[0064] In some embodiments, the power battery system can further have a second low-voltage battery assembly (not shown). The power terminals of the second low-voltage battery assembly and the output power terminals of the low-power DC conversion device are connected to the power terminals of the battery management device, and the battery management device is powered by the second low-voltage battery assembly when the low-power DC conversion device is in a non-working state, and the battery management device is powered by the low-power DC conversion device when the low-power DC conversion device is in a working state.

[0065] In some examples, the power terminals of the battery management device can be configured to be connected to the output power terminals of the low-power DC conversion device, and connected to the power terminals of the second low-voltage battery assembly via a second switching device. The second switching device is configured to be closed when the low-power DC conversion device is in a non-working state, and opened when the low-power DC conversion device is in a working state.

[0066] In some embodiments, the first low-voltage battery assembly and the second low-voltage battery assembly can be implemented as different low-voltage battery assemblies, and the first low-voltage battery assembly can implement all functions of the second low-voltage battery assembly. In some examples, the second low-voltage battery assembly can be implemented using the first low-voltage battery assembly.

[0067] In some examples, the output power terminals of the low-power DC conversion device can be connected to the power terminals of the battery management device via a reverse connection protection assembly, thereby avoiding damage to the low-power DC conversion device by external high voltage. Examples of the reverse connection protection assembly can include, but are not limited to, a diode-based reverse connection protection circuit, a MOS tube-based reverse connection protection circuit, and the like.

[0068] The low-power DC conversion device can be configured to have four working modes: a sleep mode, an initialization mode, a voltage conversion mode, and a current conversion mode, wherein the low-power DC conversion device is in an awake state in the initialization mode, the voltage conversion mode, and the current conversion mode.

[0069] The low-power DC conversion device can switch working modes under the control of the battery management device in the power battery system, thereby completing the DC conversion process.

[0070] Figure 3 An example schematic diagram of the working mode switching process of the low-power DC conversion device according to an embodiment of the present specification is shown.

[0071] As Figure 3As shown, if a wake-up command is received from the battery management device, the low-power DC-DC converter enters an initialization mode from the sleep mode to await DC-DC conversion. For example, when the battery management device determines that the high-voltage battery pack is normal, it sends a wake-up command to the low-power DC-DC converter. During the initialization mode, the low-power DC-DC converter completes the initialization process but does not perform DC-DC conversion, thus not outputting voltage.

[0072] During initialization mode, if a message indicating a high-voltage battery malfunction is received, the system switches from initialization mode to sleep mode. If a voltage level command is received, the system switches from initialization mode to voltage conversion mode, thereby converting the high-voltage electricity output from the high-voltage battery assembly into low-voltage electricity with a target voltage value.

[0073] During voltage conversion mode, if a message indicating a high-voltage battery malfunction is received, the system switches from voltage conversion mode to sleep mode. If voltage conversion is complete and a current level command is received, the system switches from voltage conversion mode to current conversion mode, thereby further converting the high-voltage electricity output from the high-voltage battery assembly into low-voltage electricity with target voltage and current values, thus completing the DC-DC conversion process. During current conversion mode, if a message indicating a high-voltage battery malfunction is received, the system switches from current conversion mode to sleep mode.

[0074] Low-power DC-DC converters can be built into the power battery system or deployed outside the power battery system.

[0075] Figure 4 A block diagram illustrating an example implementation of a vehicle power supply system according to an embodiment of this specification is shown. Figure 4 In the example, the low-power DC-DC converter is built into the power battery system.

[0076] like Figure 4 As shown, the input power terminal of the low-power DC-DC converter is located inside the high-voltage relay of the power battery system and connected to the power terminal of the high-voltage battery pack via an overcurrent and short-circuit protection device. The output power terminal of the low-power DC-DC converter is connected to the power terminal of a low-voltage load (e.g., ECU / VCU) in the vehicle's low-voltage system. Furthermore, the positive output power terminal of the low-power DC-DC converter is connected to the positive power terminal of the battery management device via a reverse connection protection component, and the negative output power terminal is connected to the negative power terminal of the battery management device.

[0077] The battery management device is also connected with the low-power DC conversion device, the low-voltage system (e.g. low-voltage battery management device) of the vehicle and the cell module controller via a data communication channel. The cell module controller is used to monitor the high-voltage battery status information of the high-voltage battery assembly, and provide the monitored high-voltage battery status information to the battery management device, so as to determine whether to wake up the low-power DC conversion device. As shown in Figure 4 The cell module controller can include a cell module controller 1 and a cell module controller 2. The cell module controller 1 is used to monitor the high-voltage battery status information of the high-voltage battery assembly (a group of cell modules cell 1 to cell 98), and the cell module controller 2 is used to monitor the high-voltage battery status information of the high-voltage battery assembly (a group of cell modules cell 99 to cell 216).

[0078] The battery management device determines the target voltage value (and target current value) of the low-power DC conversion device according to the battery capacity information (and working current information of the low-voltage load) of the first low-voltage battery assembly in the low-voltage system of the vehicle, and provides the determined target voltage value (and target current value) to the low-power DC conversion device. Then, the low-power DC conversion device converts the high-voltage power output by the high-voltage battery assembly into low-voltage power with the target voltage value (and target current value), and provides the low-voltage power to the low-voltage system of the vehicle to supply power to the low-voltage load.

[0079] During the period when the low-power DC conversion device supplies power to the low-voltage load in the low-voltage system of the vehicle, it can be determined whether to charge the first low-voltage battery assembly in the low-voltage system of the vehicle based on the target voltage value, so as to realize low-voltage power supply and low-voltage power compensation of the low-voltage system of the vehicle.

[0080] According to the implementation example of Figure 4 , since the low-power DC conversion device is arranged inside the high-voltage relay of the power battery system, the low-power DC conversion device does not close the high-voltage relay when it works, so that the power loss caused by the closing of the high-voltage relay can be eliminated.

[0081] Figure 5 Another implementation example of the vehicle power supply system according to the embodiment of the present specification is shown in the schematic diagram. In the example of Figure 5 , the low-power DC conversion device is arranged outside the power battery system. Compared with the implementation example of Figure 4 , in addition to that the low-power DC conversion device is arranged outside the high-voltage relay of the power battery system, the arrangement and structure of other components are the same as Figure 4 , which will not be described here again.

[0082] The embodiment of the present specification can also provide an electric vehicle including the vehicle power supply system as described above.

[0083] Embodiments of the present specification can also provide a battery management device located in a power battery system.

[0084] Figure 6 An example block diagram of a battery management device 600 according to embodiments of the present specification is shown. As shown, the battery management device 600 includes a DC conversion strategy determination unit 610 and a DC conversion control unit 620. Figure 6

[0085] The DC conversion strategy determination unit 610 is configured to determine a target voltage value of the low-power DC conversion device according to a battery state of charge of the first low-voltage battery assembly in the vehicle low-voltage system. The operation of the DC conversion strategy determination unit 610 can refer to the operation described above with reference to 240. Figure 2

[0086] The DC conversion control unit 620 is configured to control the low-power DC conversion device to convert the high-voltage electricity output by the high-voltage battery assembly into low-voltage electricity with the target voltage value to provide for low-voltage power supply to the vehicle low-voltage system. The operation of the DC conversion control unit 620 can refer to the operation described above with reference to 250. Figure 2

[0087] In some embodiments, the vehicle low-voltage system can also include a charging selection unit arranged between the first low-voltage battery assembly and the low-power DC conversion device. The charging selection unit is configured to select whether to charge the first low-voltage battery assembly by the low-power DC conversion device based on the target voltage value. In this case, the DC conversion strategy determination unit 610 is configured to determine the target voltage value to be such that the low-power DC conversion device does not charge the first low-voltage battery assembly during power supply to the low-voltage load in the vehicle low-voltage system when the battery state of charge of the first low-voltage battery assembly indicates that the battery charge is not lower than the nominal operating charge of the first low-voltage battery assembly; and determine the target voltage value to be such that the low-power DC conversion device charges the first low-voltage battery assembly during power supply to the low-voltage load in the vehicle low-voltage system when the battery state of charge of the first low-voltage battery assembly indicates that the battery charge is lower than the nominal operating charge of the first low-voltage battery assembly.

[0088] In some embodiments, the DC conversion strategy determination unit 610 can also be configured to determine the target voltage value of the low-power DC conversion device according to the battery state of charge of the first low-voltage battery assembly and the power consumption information of the low-voltage load in the vehicle low-voltage system.

[0089] ​​​In some embodiments, the DC conversion strategy determination unit 610 can be further configured to determine the target current value of the low-power DC conversion device according to the working current value of the low-voltage load in the low-voltage system of the vehicle. After the high-voltage power output by the high-voltage battery assembly is converted into low-voltage power with the target voltage value, the DC conversion control unit 620 controls the low-power DC conversion device to convert the high-voltage power output by the high-voltage battery assembly into low-voltage power with the target voltage value and the target current value.

[0090] In some embodiments, the power battery system can further include a cell module controller configured to acquire high-voltage battery state information of the high-voltage battery assembly. Accordingly, the battery management device can be configured to control the low-power DC conversion device not to perform DC conversion in response to the high-voltage battery state information indicating that the high-voltage battery assembly is in an abnormal state.

[0091] As described above with reference to Figures 1 to 6 , the vehicle power supply system, the battery management device, the vehicle power supply method, and the electric vehicle according to the embodiments of the present specification are described. The battery management device described above can be implemented by hardware, or by software or a combination of hardware and software.

[0092] Figure 7 An example schematic diagram of a battery management device 700 implemented based on a computer system according to an embodiment of the present specification is shown. As shown in Figure 7 , the battery management device 700 can include at least one processor 710, a memory (e.g., a non-volatile memory) 720, a memory 730, and a communication interface 740, and the at least one processor 710, the memory 720, the memory 730, and the communication interface 740 are connected together via a bus 760. The at least one processor 710 executes at least one computer-readable instruction (i.e., the elements described above implemented in the form of software) stored or encoded in the memory.

[0093] In one embodiment, computer-executable instructions stored in the memory, when executed, cause the at least one processor 710 to: determine a target voltage value of the low-power DC conversion device according to a battery power state of a first low-voltage battery assembly in a low-voltage system of a vehicle; and control the low-power DC conversion device to convert high-voltage power output by a high-voltage battery assembly into low-voltage power with the target voltage value to provide the low-voltage power to the low-voltage system of the vehicle for low-voltage power supply.

[0094] It should be understood that the computer-executable instructions stored in the memory, when executed, cause the at least one processor 710 to perform various operations and functions described in the embodiments of the present specification in combination with Figures 1 to 6 the elements described above.

[0095] According to an embodiment, a program product such as a machine-readable medium (for example, a non-transitory machine-readable medium) is provided. The machine-readable medium can have instructions (i.e., the above-mentioned elements implemented in software) stored on it that, when executed by a machine, cause the machine to perform the various operations and functions described in the embodiments of the present specification in conjunction with Figures 1 to 6 In particular, a system or apparatus equipped with a readable storage medium on which a software program code implementing the functions of any of the above-mentioned embodiments is stored, and a computer or processor of the system or apparatus can be provided to read and execute the instructions stored in the readable storage medium.

[0096] In this case, the program code read from the readable medium itself can implement the functions of any of the above-mentioned embodiments, and therefore the machine-readable code and the readable storage medium storing the machine-readable code constitute a part of the present invention.

[0097] Embodiments of the readable storage medium include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD-RW), magnetic tapes, non-volatile memory cards, and ROM. Alternatively, the program code can be downloaded from a server computer or the cloud over a communication network.

[0098] According to an embodiment, a computer program product is provided, which includes a computer program that, when executed by a processor, causes the processor to perform the various operations and functions described in the embodiments of the present specification in conjunction with Figures 1 to 6

[0099] It should be noted that not all steps and units in the above-mentioned flowcharts and system structure diagrams are necessary, and some steps or units can be omitted according to actual needs. The execution order of each step is not fixed and can be determined as needed. The device structure described in each of the above-mentioned embodiments can be a physical structure or a logical structure, that is, some units can be implemented by the same physical entity, or some units can be implemented by multiple physical entities, or some units can be implemented by some components in multiple independent devices.

[0100] ​In the above embodiments, a hardware unit or module can be implemented by mechanical means, or by electronic means, or any combination thereof. For example, a hardware unit, module or processor can include an appropriately programmed processor, or a special purpose computer, or an ASIC programmed to perform a certain operation. A hardware unit or processor can also include a combination of permanent and programmable logic, e.g., a combination of a special purpose computer and a general purpose computer, or an ASIC and a general purpose computer. The specific combinations of hardware and software are not limiting and are chosen by a designer based on cost and time considerations.

[0101] The detailed description set forth above describes exemplary embodiments and does not represent all of the only embodiments that can be practiced under the claims. The term "exemplary" used throughout this description means "serving as an example, instance, or illustration," and not "preferred" over other embodiments. The detailed description includes specific details for the purpose of providing a thorough understanding of the described techniques. These techniques, however, can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described embodiments.

[0102] The foregoing description of the present disclosure has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the disclosure be limited not with this detailed description, but rather by the claims appended hereto.

Claims

1. A vehicle power supply system for an electric vehicle, comprising: a power battery system including a high-voltage battery assembly and a battery management device; and a low-power DC conversion device configured to convert high-voltage electricity provided by the high-voltage battery assembly into low-voltage electricity and supply the converted low-voltage electricity to a low-voltage load in a vehicle low-voltage system for low-voltage power supply, wherein the battery management device is configured to: determine a target voltage value of the low-power DC conversion device according to a battery state of charge of a first low-voltage battery assembly in the vehicle low-voltage system; and control the low-power DC conversion device to convert the high-voltage electricity into low-voltage electricity with the target voltage value, the vehicle low-voltage system further comprising a first switching device arranged between the first low-voltage battery assembly and the low-power DC conversion device, wherein when the battery state of charge of the first low-voltage battery assembly indicates that the battery charge is not lower than a nominal operating charge of the first low-voltage battery assembly, the battery management device determines the target voltage value to be such that the first switching device is turned off during the low-power DC conversion device supplies power to the low-voltage load so as not to charge the first low-voltage battery assembly by the low-power DC conversion device; when the battery state of charge of the first low-voltage battery assembly indicates that the battery charge is lower than the nominal operating charge of the first low-voltage battery assembly, the battery management device determines the target voltage value to be such that the first switching device is turned on during the low-power DC conversion device supplies power to the low-voltage load so as to charge the first low-voltage battery assembly by the low-power DC conversion device.

2. The vehicle power supply system of claim 1, wherein, The battery management device is configured to determine the target voltage value of the low-power DC conversion device according to the battery state of charge of the first low-voltage battery assembly and power consumption information of the low-voltage load in the vehicle low-voltage system.

3. The vehicle power supply system of claim 1, wherein, The battery management device is further configured to: determine a target current value of the low-power DC conversion device according to an operating current value of the low-voltage load in the vehicle low-voltage system; and control the low-power DC conversion device to convert the high-voltage electricity into low-voltage electricity with the target voltage value and the target current value after the high-voltage electricity is converted into low-voltage electricity with the target voltage value.

4. The vehicle power supply system of claim 1, wherein, The power battery system further comprises a cell module controller for obtaining high-voltage battery state information of the high-voltage battery assembly, and the battery management device is configured to: in response to the high-voltage battery state information indicating that the high-voltage battery assembly is abnormal, control the low-power DC conversion device not to perform DC conversion.

5. The vehicle power supply system of claim 1, further comprising: a second low-voltage battery assembly, wherein the battery management device is configured to be powered by the second low-voltage battery assembly when the low-power DC conversion device is in a non-operating state, and to be powered by the low-power DC conversion device when the low-power DC conversion device is in an operating state.

6. The vehicle power supply system of claim 5, wherein, The power terminal of the battery management device is connected with the output power terminal of the low-power DC conversion device, and is connected with the power terminal of the second low-voltage battery assembly via a second switch device, which is configured to be closed when the low-power DC conversion device is in a non-working state, and is opened when the low-power DC conversion device is in a working state.

7. The vehicle power supply system of claim 1, wherein, The output power terminal of the low-power DC conversion device is connected with the power terminal of the battery management device via a reverse connection protection assembly.

8. The vehicle power supply system of claim 1, wherein, The input power terminal of the low-power DC conversion device is connected with the power terminal of the high-voltage battery assembly via an overcurrent and short-circuit protection device.

9. The vehicle power supply system of claim 1, wherein, The low-power DC conversion device is built in the power battery system. 10.A vehicle power supply method for an electric vehicle, comprising: obtaining a battery state of charge of a first low-voltage battery assembly in a vehicle low-voltage system; determining a target voltage value of a low-power DC conversion device according to the battery state of charge of the first low-voltage battery assembly; and controlling the low-power DC conversion device to convert high-voltage power provided by a high-voltage battery assembly in a power battery system into low-voltage power with the target voltage value to supply low-voltage loads in the vehicle low-voltage system, wherein determining the target voltage value of the low-power DC conversion device according to the battery state of charge of the first low-voltage battery assembly comprises: when the battery state of charge of the first low-voltage battery assembly indicates that the battery state of charge is not lower than a nominal working state of charge of the first low-voltage battery assembly, determining the target voltage value to be a value that causes a first switch device arranged between the first low-voltage battery assembly and the low-power DC conversion device to be off to not charge the first low-voltage battery assembly by the low-power DC conversion device during the low-power DC conversion device supplies power to the low-voltage loads; and when the battery state of charge of the first low-voltage battery assembly indicates that the battery state of charge is lower than the nominal working state of charge of the first low-voltage battery assembly, determining the target voltage value to be a value that causes the first switch device to be on to charge the first low-voltage battery assembly by the low-power DC conversion device during the low-power DC conversion device supplies power to the low-voltage loads. 11.An electric vehicle comprising the vehicle power supply system for an electric vehicle according to any one of claims 1 to 9. ​

Images