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

Abstract

The embodiment of the invention provides a vehicle power supply system for an electric vehicle, a vehicle power supply method and the electric vehicle. The vehicle power supply system comprises a power battery system and a low-power-consumption direct current conversion device. A battery management device in the power battery system determines a target voltage value of a low-power-consumption direct-current conversion device according to the battery electric quantity state of a first low-voltage battery assembly in the vehicle low-voltage system, so that the low-power-consumption direct-current conversion device is controlled to convert high-voltage electricity provided by a high-voltage battery assembly into low-voltage electricity with the target voltage value; and the converted low-voltage power is supplied to vehicle auxiliary equipment in a vehicle low-voltage system for low-voltage power supply. According to the vehicle low-voltage power supply mode, the low-voltage power supply capacity and the low-voltage power supply efficiency of the electric vehicle can be improved.

Description

Technical Field

[0001] The embodiments of this specification generally relate to the field of electric vehicles, and more particularly to a vehicle power supply system, a vehicle power supply method, and an electric vehicle for an electric vehicle. Background Art

[0002] With the development of electric vehicle technology, the functions supported by electric vehicles are becoming more and more abundant, such as sentry mode, refrigerators, etc., and the size of display screens is also getting larger and larger. As a result, the low-voltage power consumption of the vehicle low-voltage system in electric vehicles (for example, vehicle auxiliary equipment, etc.) has increased rapidly. How to improve the low-voltage power supply capacity and efficiency of electric vehicles is an urgent need in the electric vehicle field. Summary of the Invention

[0003] The embodiments of this specification provide a vehicle power supply system for an electric vehicle and an electric vehicle. Utilizing the vehicle power supply system, the low-voltage power supply capability and low-voltage power supply efficiency of the electric vehicle can be improved.

[0004] According to one aspect of an embodiment 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 DC conversion device, configured to convert the high-voltage electricity provided by the high-voltage battery assembly into low-voltage electricity, and provide the converted low-voltage electricity to the vehicle low-voltage system for low-voltage power supply, wherein the battery management device is configured to control the DC conversion process of the low-power DC conversion device according to the battery power status of the first low-voltage battery assembly in the vehicle low-voltage system.

[0005] Optionally, in an example of the above aspect, the battery management device is configured to: determine the target voltage value of the low-power DC conversion device based on the battery charge status of the first low-voltage battery assembly and the working status information of the low-voltage load; and control the low-power DC conversion device to convert the high voltage into a low voltage with a target voltage value.

[0006] Optionally, in an example of the above aspect, the vehicle low-voltage system further includes a charging selection unit provided between the first low-voltage battery assembly and the low-power DC conversion device, the charging selection unit being configured to select whether the low-power DC conversion device is to charge the first low-voltage battery assembly based on the target voltage value. The battery management device is configured to: when the battery power status of the first low-voltage battery assembly indicates that the battery power is not less than the nominal working power of the first low-voltage battery assembly, determine the target voltage value so that the low-power DC conversion device does not charge the first low-voltage battery assembly during the period of powering the low-voltage load in the vehicle low-voltage system; when the battery power status of the first low-voltage battery assembly indicates that the battery power is less than the nominal working power of the first low-voltage battery assembly, determine the target voltage value so that the low-power DC conversion device charges the first low-voltage battery assembly during the period of powering the low-voltage load in the vehicle low-voltage system.

[0007] Optionally, in an example of the above aspect, the battery management device is configured to determine the target voltage value of the low-power DC conversion device based on the battery charge status 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 an example of the above aspect, the battery management device is configured to determine the target current value of the low-power DC conversion device based on the operating current value of the low-voltage load in the vehicle low-voltage system; and after the high-voltage electricity is converted into low-voltage electricity with a target voltage value, control the low-power DC conversion device to convert the high-voltage electricity into low-voltage electricity with a target voltage value and a target current value.

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

[0010] Optionally, in an example of the above aspect, the vehicle power supply system further includes 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 converter is in a non-operating state, and to be powered by the low-power DC converter when the low-power DC converter is in an operating state.

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

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

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

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

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

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

[0017] A further understanding of the nature and advantages of the present disclosure may be achieved by referring to the following drawings, in which similar components or features may have the same reference numerals.

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

[0019] Figure 2 An exemplary flow chart 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 this specification is shown.

[0021] Figure 4A block diagram showing an implementation example of a vehicle power supply system according to an embodiment of this specification is shown.

[0022] Figure 5 A schematic diagram of another implementation example of a vehicle power supply system according to an embodiment of this specification is shown.

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

[0024] Figure 7 An exemplary 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 embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and are not intended to limit the scope of protection, applicability, or examples set forth in the claims. The functions and arrangements of the elements discussed may be changed without departing from the scope of protection of this specification. Various examples may omit, replace, or add various processes or components as needed. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted, or combined. In addition, features described relative to some examples may also be combined in other examples.

[0026] As used herein, the term "including" and its variations are open terms meaning "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 other embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other definitions may be included below, whether explicit or implicit. Unless the context clearly indicates otherwise, the definition of a term is consistent throughout the specification.

[0027] The flowcharts used in this specification illustrate operations implemented by systems according to some embodiments of the present specification. It should be clearly understood that the operations of the flowcharts may not be implemented in sequence. Rather, the operations may be implemented in reverse order or simultaneously. Furthermore, one or more additional operations may be added to the flowcharts. One or more operations may be removed from the flowcharts.

[0028] In addition to various high-voltage devices, electric vehicles also have many devices that require low-voltage power, such as the vehicle controller that controls vehicle behavior, the battery management system (BMS), the driver's instrument panel, and audio equipment. As electric vehicles support more and more functions, the number of devices requiring low-voltage power is increasing, and the size of device displays is also increasing. This has led to a rapid increase in the low-voltage power consumption of electric vehicles, necessitating the need to power and recharge the low-voltage systems of electric vehicles.

[0029] One solution for powering and replenishing a vehicle's low-voltage system utilizes a vehicle-side direct current (DC / DC) converter. This DC / DC is typically configured to power all low-voltage devices in the vehicle's low-voltage system. This requires waking up the vehicle network when the DC / DC operates, resulting in high power consumption. For example, the design power of the DC / DC is typically in the kilowatt range, resulting in low efficiency. Furthermore, the DC / DC has a limited lifespan, typically less than 20,000 hours, making it impossible to provide long-term power and energy replenishment.

[0030] In view of this, embodiments of this specification propose a vehicle power supply system for electric vehicles. This vehicle power supply system improves the low-voltage power supply capability and efficiency of electric vehicles by disposing a low-power DC / DC device, independent of the vehicle-side DC / DC device, inside or outside the power battery system. The battery management device controls the DC conversion process of the low-power DC / DC device based on the battery charge status of the low-voltage battery assembly in the vehicle's low-voltage system and the operating status of the low-voltage load.

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

[0032] Figure 1 FIG. 1 shows an exemplary block diagram of a vehicle power supply system 100 according to an embodiment of the present specification.

[0033] like Figure 1As shown, the vehicle power supply system 100 includes a low-power DC converter 110, a battery management device 120, and a high-voltage battery assembly 130. The low-power DC converter 110's positive and negative input power terminals are connected to the positive and negative power terminals of the high-voltage battery assembly 130, respectively. Under the control of the battery management device 120, the low-power DC converter 110 is configured to convert the high-voltage power output from the high-voltage battery assembly 130 into low-voltage power. For example, the low-power DC converter 110 can convert high-voltage power ranging from 300V to 1000V into low-voltage power ranging from 11V to 14V. For example, the low-power DC converter 110 can be connected to the high-voltage battery assembly 130 via a high-voltage input unit. In some embodiments, an overcurrent and short-circuit protection device can be provided between the low-power DC converter 110 and the high-voltage battery assembly 130 to provide overcurrent and short-circuit protection. Examples of the overcurrent and short-circuit protection device include a fuse. It should be noted that, in this specification, the term "low-power DC conversion device" is used to refer to a DC conversion device that can perform voltage-to-DC conversion and consumes low power when performing DC conversion.

[0034] The high-voltage battery assembly 130 can be, for example, a high-voltage battery pack that powers an electric vehicle. The high-voltage battery assembly 130 can draw power from the power grid via an onboard charger. The high-voltage battery assembly 130 can include multiple serially connected battery cell modules, for example, 216 battery cell modules, each with a positive terminal and a negative terminal.

[0035] The positive power terminal at the output end and the negative power terminal at the output end of the low-power DC conversion device 110 are respectively connected to the positive power terminal and negative power terminal of the vehicle low-voltage system 140, and are used to provide the converted low-voltage electricity to the vehicle low-voltage system 140, thereby powering the low-voltage load in the vehicle low-voltage system 140, and thus enabling the low-voltage load to operate normally.

[0036] The vehicle low-voltage system 140 may include a first low-voltage battery assembly and a low-voltage load. The first low-voltage battery assembly is configured to supply power to the low-voltage load. The first low-voltage battery assembly may be, for example, a small 12V battery. Examples of low-voltage loads may include, but are not limited to, a vehicle control unit (ECU or VCU), a battery management device, a driver's instrument panel, audio equipment, or other vehicle auxiliary equipment. Optionally, the vehicle low-voltage system 140 may further include a low-voltage battery management system (LVBMS) for performing battery management for the first low-voltage battery assembly in the vehicle low-voltage system. The positive and negative power terminals of the first low-voltage battery assembly are connected to the positive and negative power terminals of the low-voltage battery management system, respectively.

[0037] The low-power DC converter 110 and the first low-voltage battery assembly are configured to be connected in parallel to supply power to a low-voltage load in the vehicle's low-voltage system. For example, the positive power terminal and the negative power terminal of the output end of the low-power DC converter 110 can be configured to be connected to the positive power terminal and the negative power terminal of the low-voltage load in the vehicle's low-voltage system, respectively, and the positive power terminal and the negative power terminal of the first low-voltage battery assembly can be configured to be connected to the positive power terminal and the negative power terminal of the low-voltage load in the vehicle's 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 the battery charge state of the first low-voltage battery assembly in the vehicle low-voltage system. The battery charge state of the first low-voltage battery assembly can be represented qualitatively or quantitatively. The qualitative representation of the battery charge state may include, for example, a battery low-power state, a nominal charge state, and a full-charge state. The battery low-power state is used to indicate that the output power of the battery is lower than the nominal power, the nominal charge state is used to indicate that the output power of the battery is equal to the nominal power, and the full-charge state is used to indicate that the output power reaches the maximum output power of the battery. The quantitative representation of the battery charge state may include, for example, the actual output power of the battery (absolute output power value) or the percentage of the actual output power of the battery to the full-charge state.

[0039] The battery management device 120 can communicate data with the vehicle low-voltage system 140 to obtain the battery charge state 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 converter 110 based on the battery charge state of the first low-voltage battery assembly. The battery charge state of the first low-voltage battery assembly can be sensed, for example, 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. In some embodiments, the battery management device 120 can communicate data with the vehicle low-voltage system 140 via wired or wireless communication. For example, the battery management device 120 can communicate data with the vehicle low-voltage system 140 based on CAN, Lin, SPI, or FlexRay.

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

[0041] Optionally, the vehicle low-voltage system 140 may further include a charging selection unit disposed between the first low-voltage component and the low-power DC converter. The charging selection unit is configured to select whether to charge the first low-voltage component based on a target voltage value while the low-power DC converter is supplying power to the low-voltage load. The charging selection unit may be implemented, for example, using a first switching device Q1. The first switching device Q1 may be disposed, for example, between the positive power terminal of the first low-voltage battery assembly, the output positive power terminal of the low-power DC converter 110, and the positive power terminal of the low-voltage load in the vehicle low-voltage system, to control the connection and disconnection between the first low-voltage battery assembly, the low-power DC converter 110, and the low-voltage load in the vehicle low-voltage system. Examples of the first switching device may include, for example, a mechanical switching device, a relay, a semiconductor switching device, and the like. Semiconductor switching devices may include, for example, a diode, a thyristor, a transistor, a MOSFET, an IGBT, and the like.

[0042] The battery management device 120 may also be referred to as a battery management system (BMS), and together with the high-voltage battery assembly 130 , as components of a power battery system, constitutes a power battery system.

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

[0044] like Figure 2 As shown, at 210 , the battery management device 120 obtains high-voltage battery status information of the high-voltage battery assembly. The high-voltage battery status information is used to indicate whether the high-voltage battery assembly is abnormal, for example, the high-voltage battery is low in power or has a fault.

[0045] In some embodiments, the power battery system may also include one or more cell module controllers (CMCs). When multiple cell module controllers are present, they communicate with each other, and each CMC is configured to monitor the high-voltage battery status information of a group of cell modules. This monitored high-voltage battery status information is then uploaded to the battery management unit 120. For example, a data communication channel may be established between the cell module controllers and the battery management unit 120, and the high-voltage battery status information is uploaded to the battery management unit 120 via the data communication channel.

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

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

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

[0049] At 240 , the battery management device 120 determines a target voltage value of the low-power DC converter 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 disposed between the first low-voltage battery assembly and the low-power DC converter device. The charging selection unit is configured to select whether the low-power DC converter device 110 charges the first low-voltage battery assembly based on the target voltage value.

[0051] When the battery power status of the first low-voltage battery assembly indicates that the battery power is not less than the nominal operating power of the first low-voltage battery assembly, the battery management device 120 may determine the target voltage value so that the low-power DC conversion device does not charge the first low-voltage battery assembly while supplying power to the low-voltage load. When the battery power status of the first low-voltage battery assembly indicates that the battery power is less than the nominal operating power of the first low-voltage battery assembly, the battery management device 120 may determine the target voltage value so that the first low-voltage battery assembly is charged while the low-power DC conversion device is supplying power to the low-voltage load.

[0052] For example, when the charging selection unit is implemented using a switching device, when the battery power status of the first low-voltage battery assembly indicates that the battery power is not less than the nominal operating power of the first low-voltage battery assembly, assuming that the nominal operating power is M volts (the voltage value after voltage conversion) and the conduction voltage of the switching device is N volts, the target voltage value can be determined as a voltage value not exceeding M+V. When the battery power status of the first low-voltage battery assembly indicates that the battery power is less than the nominal operating power of the first low-voltage battery assembly, the target voltage value can be determined as 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 a pre-set voltage gear. The voltage gear can be determined based on the output voltage value 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 gear can be set to 8v, 10v, 12v and 24v, or to a voltage range 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 gear based on the battery power state of the first low-voltage battery assembly.

[0054] In some embodiments, power consumption information of low-voltage loads in the vehicle's low-voltage system may also be obtained, and a target voltage value for the low-power DC converter may be determined based on the battery charge state of the first low-voltage battery assembly and the power consumption information of the low-voltage loads. For example, if the power consumption of the low-voltage loads is high, a higher target voltage value may be selected.

[0055] In some embodiments, operating parameters of the first low-voltage battery assembly may also be obtained, and a target voltage value of the low-power DC converter may be determined based on the battery charge state and operating parameters of the first low-voltage battery assembly. For example, when the low-power DC converter is charging the first low-voltage battery assembly, the selected target voltage value may need to meet the operating parameter requirements of the first low-voltage battery assembly.

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

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

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

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

[0060] In some embodiments, the charging selection unit can be implemented using a first switching device Q1. Accordingly, the output positive power terminal and the output negative power terminal of the low-power DC converter 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 converter 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 so that the voltage difference from the current charge of the first low-voltage battery assembly exceeds the turn-on voltage of the first switching device Q1, the first switching device Q1 is turned on, thereby the low-power DC conversion device 110 charges the first low-voltage battery assembly while supplying power to the low-voltage load. If the target voltage value is selected so that the voltage difference from the current charge of the first low-voltage battery assembly does not exceed the turn-on voltage of the first switching device Q1, the first switching device Q1 is turned off, thereby the low-power DC conversion device 110 does not charge the first low-voltage battery assembly while supplying power to the low-voltage load.

[0062] The vehicle low-voltage system may also be provided with a low-voltage battery management device for monitoring the low-voltage battery status information of the first low-voltage battery assembly and providing the low-voltage battery status information to the battery management device in the power battery system.

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

[0064] In some embodiments, the power battery system may further include 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 converter are connected to the power terminals of the battery management device. When the low-power DC converter is in an inoperative state, the second low-voltage battery assembly supplies power to the battery management device. When the low-power DC converter is in an operative state, the low-power DC converter supplies power to the battery management device.

[0065] In some examples, the power terminal of the battery management device can be configured to be connected to the output power terminal of the low-power DC converter device and connected to the power terminal of the second low-voltage battery assembly via a second switching device. The second switching device is configured to close when the low-power DC converter device is in a non-operating state and to open when the low-power DC converter device is in an operating 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 perform 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 terminal of the low-power DC converter device can be connected to the power terminal of the battery management device via a reverse polarity protection component, thereby preventing damage to the low-power DC converter device from external high voltage. Examples of reverse polarity protection components include, but are not limited to, diode-based reverse polarity protection circuits and MOS transistor-based reverse polarity protection circuits.

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

[0069] The low-power DC conversion device can switch the working mode 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 a working mode switching process of a low-power DC conversion device according to an embodiment of this specification is shown.

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

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

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

[0074] The low-power DC conversion device can be built into the power battery system or deployed outside the power battery system.

[0075] Figure 4 FIG1 shows an example block diagram of a vehicle power supply system according to an embodiment of the present specification. Figure 4 In the example, the low-power DC conversion device is built into the power battery system.

[0076] like Figure 4 As shown, the input power terminal of the low-power direct current converter is located inside the high-voltage relay of the power battery system and is 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 direct conversion device is connected to the power terminal of the low-voltage load (e.g., ECU / VCU) in the vehicle's low-voltage system. Furthermore, the positive power terminal of the low-power direct current converter is connected to the positive power terminal of the battery management unit via a reverse polarity protection component, and the negative power terminal of the low-power direct current converter is connected to the negative power terminal of the battery management unit.

[0077] The battery management device is also connected to the low-power DC converter, the vehicle's low-voltage system (e.g., the low-voltage battery management device), 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 to determine whether to wake up the low-power DC converter. Figure 4 As shown, the cell module controller may 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 (and target current) for the low-power DC converter based on the battery charge information of the first low-voltage battery assembly in the vehicle's low-voltage system (and the operating current information of the low-voltage load) and provides the determined target voltage (and target current) to the low-power DC converter. The low-power DC converter then converts the high-voltage power output from the high-voltage battery assembly into low-voltage power with the target voltage (and target current) and provides it to the vehicle's low-voltage system to power the low-voltage load.

[0079] During the period when the low-power DC conversion device is supplying power to the low-voltage load in the vehicle's low-voltage system, it can be determined whether to charge the first low-voltage battery assembly in the vehicle's low-voltage system based on the target voltage value, thereby realizing low-voltage power supply and low-voltage power replenishment of the vehicle's low-voltage system.

[0080] according to Figure 4 In an implementation example, since the low-power DC conversion device is arranged inside the high-voltage intermediate circuit of the power battery system, the high-voltage repeater will not be closed when the low-power DC conversion device is working, thereby eliminating the power loss caused by the closing of the high-voltage repeater.

[0081] Figure 5 FIG2 shows another exemplary implementation diagram of a vehicle power supply system according to an embodiment of the present specification. Figure 5 In the example, the low-power DC conversion device is arranged outside the power battery system. Figure 4 Compared with the implementation example of the present invention, except that the low-power DC device is arranged outside the high-voltage relay of the power battery system, the arrangement and structure of other components are the same as those of the present invention. Figure 4 The same, no longer repeated here.

[0082] The embodiments of this specification may also provide an electric vehicle, which includes the vehicle power supply system as described above.

[0083] The embodiments of this specification may also provide a battery management device located in a power battery system.

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

[0085] The DC conversion strategy determination unit 610 is configured to determine the target voltage value of the low power DC conversion device according to the battery power state 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 above reference. Figure 2 The operation of 240 is described.

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

[0087] In some embodiments, the vehicle low-voltage system may further include a charging selection unit disposed between the first low-voltage battery assembly and the low-power DC conversion device. The charging selection unit is configured to select whether the low-power DC conversion device is to charge the first low-voltage battery assembly based on the target voltage value. In this case, the DC conversion strategy determination unit 610 is configured to, when the battery power status 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, determine the target voltage value so that the low-power DC conversion device does not charge the first low-voltage battery assembly during the period of powering the low-voltage load in the vehicle low-voltage system; and, when the battery power status 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, determine the target voltage value so that the low-power DC conversion device charges the first low-voltage battery assembly during the period of powering the low-voltage load in the vehicle low-voltage system.

[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 based on the battery charge status 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 may also be configured to determine a target current value for the low-power DC converter device based on the operating current value of the low-voltage load in the vehicle's low-voltage system. After the high-voltage power output by the high-voltage battery assembly is converted into low-voltage power having a target voltage value, the DC conversion control unit 620 controls the low-power DC converter device to convert the high-voltage power output by the high-voltage battery assembly into low-voltage power having the target voltage and target current values.

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

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

[0092] Figure 7 FIG. 7 shows an example schematic diagram of a battery management device 700 implemented based on a computer system according to an embodiment of the present specification. Figure 7 As shown, the battery management device 700 may include at least one processor 710, a memory (e.g., a non-volatile memory) 720, a storage 730, and a communication interface 740, and the at least one processor 710, the memory 720, the storage 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 stored or encoded in the memory (i.e., the above-mentioned elements implemented in the form of software).

[0093] In one embodiment, computer executable instructions are stored in a memory, which, when executed, cause at least one processor 710 to: determine a target voltage value of a low-power DC conversion device based on the battery charge status 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 the high-voltage electricity output by the high-voltage battery assembly into low-voltage electricity with a target voltage value to provide low-voltage power to the low-voltage system of the vehicle.

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

[0095] According to one embodiment, a program product such as a machine-readable medium (e.g., a non-transitory machine-readable medium) is provided. The machine-readable medium may have instructions (i.e., the elements implemented in the form of software) that, when executed by a machine, cause the machine to perform the various embodiments of this specification. Figures 1 to 6 Specifically, a system or device equipped with a readable storage medium can be provided, on which software program codes for implementing the functions of any of the above-mentioned embodiments are stored, and a computer or processor of the system or device can be enabled to read and execute the instructions stored in the readable storage medium.

[0096] In this case, the program code itself read from the machine-readable medium can realize the function of any one of the above embodiments, and thus the machine-readable code and the machine-readable storage medium storing the machine-readable code constitute part of the present invention.

[0097] Examples of readable storage media include floppy disks, hard disks, magneto-optical disks, optical disks (e.g., CD-ROMs, CD-Rs, CD-RWs, DVD-ROMs, DVD-RAMs, DVD-RWs, DVD-RWs), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, the program code may be downloaded from a server computer or a cloud via a communication network.

[0098] According to one embodiment, a computer program product is provided. The computer program product includes a computer program. When the computer program is executed by a processor, the processor performs various embodiments of the present specification in combination with Figures 1 to 6 Describes the various operations and functions.

[0099] It should be noted that not all steps and units in the above processes and system structure diagrams are required, and certain 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 the above embodiments can be a physical structure or a logical structure, that is, some units may be implemented by the same physical entity, or some units may be implemented by multiple physical entities, or may be implemented by certain components in multiple independent devices.

[0100] In the above embodiments, the hardware unit or module can be implemented mechanically or electrically. For example, a hardware unit, module, or processor may include permanent dedicated circuits or logic (such as a dedicated processor, FPGA, or ASIC) to complete the corresponding operation. The hardware unit or processor may also include programmable logic or circuits (such as a general-purpose processor or other programmable processor), which can be temporarily configured by software to complete the corresponding operation. The specific implementation method (mechanical method, dedicated permanent circuit, or temporarily configured circuit) can be determined based on cost and time considerations.

[0101] The specific embodiments described above in conjunction with the accompanying drawings describe exemplary embodiments, but do not represent all embodiments that can be implemented or fall within the scope of protection of the claims. The term "exemplary" used throughout this specification means "used as an example, instance or illustration" and does not mean "preferred" or "having advantages" over other embodiments. For the purpose of providing an understanding of the described technology, the specific embodiments include specific details. However, these technologies can be implemented without these specific details. In some instances, in order to avoid obscuring the concepts of the described embodiments, well-known structures and devices are shown in block diagram form.

[0102] The foregoing description of the present disclosure is provided to enable any person skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Therefore, the present disclosure is not limited to the examples and designs described herein, but is intended to be consistent with the widest range of principles and novel features disclosed herein.

Claims

1. A vehicle power supply system for an electric vehicle, comprising: A power battery system comprising a high-voltage battery assembly and a battery management device; as well as The low-power DC converter is configured to convert the high-voltage electricity provided by the high-voltage battery assembly into low-voltage electricity, and provide the converted low-voltage electricity to the vehicle low-voltage system for low-voltage power supply. Wherein, the battery management device is configured to control the DC conversion process of the low-power DC conversion device according to the battery power state of the first low-voltage battery assembly in the vehicle low-voltage system.

2. The vehicle power supply system according to claim 1, wherein: The battery management device is configured to: determining a target voltage value of the low-power DC conversion device according to the battery power state of the first low-voltage battery assembly; as well as The low-power DC conversion device is controlled to convert the high-voltage electricity into low-voltage electricity with a target voltage value.

3. The vehicle power supply system according to claim 2, wherein: The vehicle low-voltage system further includes a charging selection unit disposed between the first low-voltage battery assembly and the low-power DC conversion device, wherein the charging selection unit is configured to select whether the low-power DC conversion device is to charge the first low-voltage battery assembly based on the target voltage value. The battery management device is configured to: When the battery power status of the first low-voltage battery assembly indicates that the battery power is not less than the nominal operating power of the first low-voltage battery assembly, the target voltage value is determined so that the low-power DC conversion device does not charge the first low-voltage battery assembly during the period of supplying power to the low-voltage load in the vehicle low-voltage system; When the battery power status of the first low-voltage battery assembly indicates that the battery power is lower than the nominal operating power of the first low-voltage battery assembly, the target voltage value is determined so that the low-power DC conversion device charges the first low-voltage battery assembly while supplying power to the low-voltage load in the vehicle low-voltage system.

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

5. The vehicle power supply system according to claim 2, wherein: The battery management device is further configured to: determining a target current value of the low-power DC converter device according to an operating current value of a low-voltage load in the vehicle low-voltage system; and After the high voltage electricity is converted into low voltage electricity with a target voltage value, the low power consumption DC conversion device is controlled to convert the high voltage electricity into low voltage electricity with a target voltage value and a target current value.

6. The vehicle power supply system according to claim 2, wherein: The power battery system further includes a cell module controller for obtaining high-voltage battery status information of the high-voltage battery assembly. The battery management device is configured to: In response to the high-voltage battery status information indicating that the high-voltage battery assembly is in an abnormal state, the low-power consumption DC conversion device is controlled not to perform DC conversion.

7. The vehicle power supply system according to claim 1, further comprising: The second low-voltage battery assembly, In which, 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-working state, and to be powered by the low-power DC conversion device when the low-power DC conversion device is in a working state.

8. The vehicle power supply system according to claim 7, wherein: The power terminal of the battery management device is connected to the output power terminal of the low-power DC conversion device, and is connected to the power terminal of the second low-voltage battery assembly via a second switching device. The second switching device is configured to close when the low-power DC conversion device is in a non-working state, and to open when the low-power DC conversion device is in a working state.

9. The vehicle power supply system according to claim 7, wherein: The output power terminal of the low-power DC conversion device is connected to the power terminal of the battery management device via a reverse connection protection component.

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

11. The vehicle power supply system according to claim 1, wherein: The low-power DC conversion device is built into the power battery system.

12. A vehicle power supply method for an electric vehicle, comprising: Obtaining a battery power state of a first low-voltage battery assembly in a low-voltage system of a vehicle; Determining a target voltage value of the low-power DC conversion device according to the battery power state of the first low-voltage battery assembly; as well as The low-power DC conversion device is controlled to convert the high-voltage electricity provided by the high-voltage battery assembly in the power battery system into low-voltage electricity with the target voltage value, so as to provide low-voltage power to the vehicle low-voltage system.

13. An electric vehicle comprising the vehicle power supply system for an electric vehicle according to any one of claims 1 to 11.

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