Low-voltage power supply system and vehicle

Abstract

The utility model provides a low-voltage power supply system and a vehicle. The system comprises a first low-voltage redundant power supply loop, a second low-voltage redundant power supply loop and a third low-voltage redundant power supply loop, the first low-voltage redundant power supply loop, the second low-voltage redundant power supply loop and the third low-voltage redundant power supply loop respectively comprise a battery pack of the power battery and a direct-current voltage converter, the input end of the direct-current voltage converter is connected with the output end of the battery pack of the power battery, and the voltages of the multiple battery packs of the power battery are equal; the output ends of the direct-current voltage converters in the first low-voltage redundant power supply loop and the second low-voltage redundant power supply loop are connected with the input end of a first low-voltage power supply; the output end of the direct-current voltage converter in the third low-voltage redundant power supply loop is connected with the input end of the second low-voltage power supply; the output end of the first low-voltage power supply and the output end of the second low-voltage power supply are used for connecting a low-voltage load. According to the system, the energy loss and the potential safety hazard of voltage conversion are reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and in particular to a low-voltage power supply system and a vehicle. Background Art

[0002] With the continuous advancement of electric vehicle technology and the growing market demand, the increase in power battery voltage has become an inevitable trend in the development of electric vehicles. The increase in power battery voltage can significantly improve the energy efficiency, acceleration performance and overall driving experience of electric vehicles. High voltage not only means higher energy density, but also means smaller internal resistance and higher energy transmission efficiency, which is crucial to improving the range and driving performance of electric vehicles.

[0003] In the context of increasing the voltage of power batteries, the high-voltage to low-voltage system has become an indispensable part of electric vehicles. At present, many OEMs usually use high-voltage and high-power devices to achieve high-low voltage conversion. These devices have the ability to withstand high voltage and high current, and can stably convert the high-voltage electricity output by the power battery into low-voltage electricity to meet the use requirements of various low-voltage electrical equipment in the vehicle. In addition, in order to ensure the stability and safety of the system, it is usually necessary to set up corresponding protection and control circuits in the system to ensure that the power supply can be quickly cut off in abnormal situations and prevent accidents.

[0004] However, there will be a certain amount of energy loss in the process of converting high voltage to low voltage using high-voltage resistant and high-power devices, which will affect the range of electric vehicles. In addition, the arrangement of high-voltage cables in the whole vehicle will increase the risk of electromagnetic compatibility (EMC) interference and pose a safety hazard of high-voltage leakage. Utility Model Content

[0005] The present application provides a low-voltage power supply system and a vehicle, which are used to solve the problem of potential safety hazards in the prior art of using high-voltage resistant, high-power devices to convert high voltage into low voltage.

[0006] In a first aspect, the present application provides a low-voltage power supply system, comprising: a first low-voltage redundant power supply circuit, a second low-voltage redundant power supply circuit, and a third low-voltage redundant power supply circuit;

[0007] The first low-voltage redundant power supply circuit, the second low-voltage redundant power supply circuit and the third low-voltage redundant power supply circuit respectively include a battery pack of a power battery and a direct current converter (Direct Current-Direct Current Converter, DCDC), the input end of the DCDC is connected to the output end of a battery pack of the power battery, and the voltages of the multiple battery packs of the power battery are equal;

[0008] The output ends of the DCDC in the first low-voltage redundant power supply loop and the second low-voltage redundant power supply loop are both connected to the input end of the first low-voltage power supply;

[0009] The output end of the DCDC in the third low-voltage redundant power supply loop is connected to the input end of the second low-voltage power supply;

[0010] The output end of the first low-voltage power supply and the output end of the second low-voltage power supply are used to connect to a low-voltage load.

[0011] In a possible design, the functional safety integrity level (Automotive Safety Integrity Level, ASIL) of the DCDC in the first low-voltage redundant power supply circuit and the second low-voltage redundant power supply circuit is A;

[0012] The ASIL of the DCDC in the third low-voltage redundant power supply circuit is level B.

[0013] In one possible design, the system further includes: a fourth low-voltage redundant power supply circuit;

[0014] The fourth low-voltage redundant power supply circuit includes a battery pack of a power battery and a DCDC;

[0015] The output end of the DCDC in the fourth low-voltage redundant power supply loop is connected to the input end of the second low-voltage power supply.

[0016] In a possible design, the ASIL of the DCDC in the first low-voltage redundant power supply loop, the second low-voltage redundant power supply loop, the third low-voltage redundant power supply loop, and the fourth low-voltage redundant power supply loop are all Class A.

[0017] In a possible design, the ASIL of the first low-voltage power supply and the second low-voltage power supply are both level B.

[0018] In a possible design, the output end of the first low-voltage power supply is used to connect to the low-voltage load through a load switch;

[0019] The output end of the second low-voltage power supply is used to be connected to the low-voltage load through a load switch.

[0020] In a possible design, the output end of the first low-voltage power supply is used to connect to a first end of an automated driving control unit (ADCU);

[0021] The output end of the second low-voltage power supply is used to connect to the second end of the ADCU.

[0022] In one possible design, the system further includes a plurality of battery management systems (BMS);

[0023] Each BMS is used to monitor a battery pack of the power battery.

[0024] In one possible design, the system further includes a plurality of pre-charging circuits;

[0025] A battery pack of the power battery is connected to the DCDC through a pre-charging circuit.

[0026] In a second aspect, the present application provides a vehicle, comprising the first aspect and any one of the low-voltage power supply systems in the embodiments involved in the first aspect.

[0027] The low-voltage power supply system and vehicle provided in the present application divide the power battery into multiple battery packs and use multiple parallel DCDCs to convert the high and low voltages of one battery pack respectively, so as to avoid using a high-voltage and high-power DCDC to directly convert the high voltage of the power battery, reduce energy loss in the voltage conversion process, reduce safety hazards, and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A schematic diagram of the structure of a low-voltage power supply system provided in one embodiment of the present application;

[0030] Figure 2 A schematic diagram of the structure of another low-voltage power supply system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] The terms "first", "second", "third", "fourth", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances. For example, without departing from the scope of this document, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information.

[0033] It should be further understood that the terms “comprises” and “includes” indicate the existence of features, steps, operations, elements, components, items, types, and / or groups, but do not exclude the existence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, types, and / or groups.

[0034] The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Thus, "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". An exception to this definition will only occur when a combination of elements, functions, steps or operations are inherently mutually exclusive in some manner.

[0035] Terminology explanation:

[0036] Electromagnetic compatibility: refers to the ability of a device or system to operate normally as required in its electromagnetic environment without causing intolerable electromagnetic disturbance or interference to any device in its environment.

[0037] Electrical clearance: refers to the shortest space distance measured between two conductive parts or between a conductive part and the protective interface of the equipment. That is, the shortest distance that can be insulated through air while ensuring stable and safe electrical performance.

[0038] Creepage distance: The shortest path between two conductive parts or between a conductive part and the protective interface of the equipment measured along the insulating surface. Under different usage conditions, the insulating material around the conductor is polarized, causing the insulating material to become charged. The radius of this charged area is the creepage distance.

[0039] Low-voltage power supply: Low-voltage 12V lithium battery used in electric vehicles to power low-voltage discharge loads.

[0040] Redundant backup: Duplicate key components or the main functions of the system to improve system stability.

[0041] BMS: Battery Manager, is mainly used to intelligently manage and maintain each battery unit, prevent the battery from overcharging and over-discharging, extend the battery life, and monitor the battery status.

[0042] Electric vehicles are obviously superior to traditional vehicles in terms of electrification, intelligence, and comfort. However, with the continuous advancement of electric vehicle technology and the growing market demand, the increase in power battery voltage has become an inevitable trend in the development of electric vehicles. In order to alleviate the problems caused by the range of driving, OEMs usually increase the capacity of batteries and increase the voltage platform of batteries to increase the energy of power batteries. For example, the voltage of power batteries is increased from 400V and 600V to 800V or even higher voltage platforms. The increase in power battery voltage can significantly improve the energy efficiency, acceleration performance and overall driving experience of electric vehicles. High voltage not only means higher energy density, but also means smaller internal resistance and higher energy transmission efficiency, which is crucial to improving the range and driving performance of electric vehicles. Therefore, the increase in power battery voltage is of great significance to the development of the electric vehicle industry.

[0043] In the context of increasing the voltage of power batteries, the high-voltage to low-voltage system has become an indispensable part of electric vehicles. At present, many OEMs usually use high-voltage and high-power devices to achieve high-low voltage conversion. These devices have the ability to withstand high voltage and high current, and can stably convert the high-voltage electricity output by the power battery into low-voltage electricity to meet the use requirements of various low-voltage electrical equipment in the vehicle. In addition, in order to ensure the stability and safety of the system, it is usually necessary to set up corresponding protection and control circuits in the system to ensure that the power supply can be quickly cut off in abnormal situations and prevent accidents.

[0044] Although the current high-voltage to low-voltage system can meet the use needs of electric vehicles to a certain extent, there are still some problems in practical applications. First, due to the limitation of energy conversion efficiency, there will be a certain amount of energy loss in the process of high-voltage to low-voltage conversion using high-voltage resistant and high-power devices, which will affect the range of electric vehicles. Secondly, the cost of high-voltage resistant and high-power devices is high, which increases the overall cost of the system, and also increases the difficulty and cost of subsequent maintenance. In addition, the arrangement of high-voltage cables in the whole vehicle will increase the risk of EMC interference and pose a safety hazard of high-voltage leakage. In order to ensure the safety of the system, it is necessary to improve the insulation performance requirements and increase the electrical clearance and creepage distance, which further increases the weight and layout space of the DCDC. Finally, with the development of autonomous driving technology, the demand for high and low voltage redundant power supply in systems such as high-order autonomous driving systems, wire-controlled steering and wire-controlled braking has also increased the complexity and cost of the system.

[0045] In response to the above problems, this application proposes a low-voltage power supply system and vehicle. By dividing the power battery into multiple battery packs, that is, splitting the high-voltage circuit into multiple low-voltage circuits, multiple parallel DCDCs are used to convert high and low voltages of a battery pack respectively, thereby avoiding the use of high-voltage and high-power DCDCs to directly convert the high voltage of the power battery, reducing energy loss in the voltage conversion process, reducing safety hazards, and reducing costs.

[0046] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0047] Figure 1 FIG. 1 shows a schematic diagram of a low voltage power supply system provided by an embodiment of the present application. Figure 1 As shown, the low-voltage power supply system of this embodiment includes a first low-voltage redundant power supply circuit, a second low-voltage redundant power supply circuit and a third low-voltage redundant power supply circuit.

[0048] The first low-voltage redundant power supply circuit, the second low-voltage redundant power supply circuit and the third low-voltage redundant power supply circuit respectively include a battery pack of a power battery and a DCDC, the input end of the DCDC is connected to the output end of a battery pack of the power battery, and the voltages of the multiple battery packs of the power battery are equal.

[0049] The output ends of the DCDC in the first low-voltage redundant power supply loop and the second low-voltage redundant power supply loop are both connected to the input end of the first low-voltage power supply; the output end of the DCDC in the third low-voltage redundant power supply loop is connected to the input end of the second low-voltage power supply.

[0050] The output end of the first low-voltage power supply and the output end of the second low-voltage power supply are used to connect to a low-voltage load.

[0051] In this embodiment, the voltages of the multiple battery packs of the power battery are equal, which may be completely equal, or the voltage difference between the battery packs may be within a preset range.

[0052] For example, Figure 1 The voltage of the medium power battery is 600V, and the voltages of battery packs 1, 2, and 3 are 200V respectively. The output of each battery pack is connected to the input of a DCDC respectively, and the output of the DCDC is connected to a low-voltage power supply. The DCDC converts the 200V voltage into a 12V voltage, and the low-voltage power supply supplies power to the low-voltage load and ADCU.

[0053] The low-voltage power supply system provided in this embodiment, by splitting the power battery into three battery packs, uses three parallel DCDCs to convert the three battery packs into high and low voltages respectively, thereby avoiding directly converting the high voltage of the power battery into a 12V low voltage, reducing energy loss during the voltage conversion process, reducing the risk of EMC interference, reducing safety hazards, and reducing costs.

[0054] In some embodiments, the ASIL of the DCDC in the first low-voltage redundant power supply loop and the second low-voltage redundant power supply loop is Class A; the ASIL of the DCDC in the third low-voltage redundant power supply loop is Class B. The ASIL of the first low-voltage power supply and the second low-voltage power supply are both Class B.

[0055] In this embodiment, the first low-voltage redundant power supply circuit and the second low-voltage redundant power supply circuit can meet the power supply requirement of ASIL A when supplying power independently, and can meet the power supply requirement of ASIL B when supplying power together.

[0056] The third low-voltage redundant power supply circuit can meet the power supply requirements of ASIL B. The three power supply circuits can jointly supply power to meet the power supply requirements of ASIL C and ASIL D.

[0057] That is to say, the low-voltage power supply system provided in this embodiment, by setting up a low-voltage redundant power supply circuit, when a battery pack fails or a DCDC fails, the remaining battery packs and DCDC can still continue to supply power to the entire vehicle, thereby meeting the degraded driving of the vehicle's autonomous driving, and meeting the high and low voltage redundant power supply requirements of autonomous driving L3 and above, such as wire-controlled steering and wire-controlled braking.

[0058] Figure 2 FIG. 2 shows a schematic diagram of the structure of another low-voltage power supply system provided by an embodiment of the present application. Figure 2 As shown, in Figure 1 Based on the illustrated embodiment, the low-voltage power supply system may further include a fourth low-voltage redundant power supply circuit.

[0059] The fourth low-voltage redundant power supply circuit includes a battery pack 4 of a power battery and a DCDC.

[0060] The output end of the DCDC in the fourth low-voltage redundant power supply loop is connected to the input end of the second low-voltage power supply.

[0061] For example, Figure 2 The voltage of the medium power battery is 800V, and the voltages of battery packs 1, 2, 3, and 4 are 200V respectively. The output of each battery pack is connected to the input of a DCDC respectively, and the output of the DCDC is connected to a low-voltage power supply. The DCDC converts the 200V voltage into a 12V voltage, and the low-voltage power supply supplies power to the low-voltage load and ADCU.

[0062] The low-voltage power supply system provided in this embodiment, by splitting the power battery into four battery packs, uses four parallel DCDCs to convert the four battery packs into high and low voltages respectively, thereby avoiding directly converting the high voltage of the power battery into a 12V low voltage, reducing energy loss during the voltage conversion process, reducing the risk of EMC interference, reducing safety hazards, and reducing costs.

[0063] In some embodiments, the ASIL of the DCDC in the first low-voltage redundant power supply loop, the second low-voltage redundant power supply loop, the third low-voltage redundant power supply loop, and the fourth low-voltage redundant power supply loop are all level A. The ASIL of the first low-voltage power supply and the second low-voltage power supply are both level B.

[0064] In this embodiment, the four low-voltage redundant power supply circuits can meet the power supply requirements of ASIL A when they are powered separately, the first low-voltage redundant power supply circuit and the second low-voltage redundant power supply circuit can meet the power supply requirements of ASIL B when they are powered together, and the third low-voltage redundant power supply circuit and the fourth low-voltage redundant power supply circuit can meet the power supply requirements of ASIL B when they are powered together. The four power supply circuits can meet the power supply requirements of ASIL C and ASIL D.

[0065] Similar to the above-mentioned embodiment, the low-voltage power supply system provided in this embodiment sets a low-voltage redundant power supply circuit. When a battery pack fails or a DCDC fails, the remaining battery packs and DCDC can still continue to supply power to the entire vehicle, meeting the downgraded driving of the vehicle's autonomous driving and meeting the high and low voltage redundant power supply requirements of autonomous driving L3 and above, such as wire-controlled steering and wire-controlled braking. In addition, according to the power requirements of the low-voltage power supply system, the withstand voltage performance of the DCDC, and the cost of the device, three or four low-voltage redundant power supply circuits can be selected to save costs while meeting the low-voltage power supply requirements.

[0066] In some embodiments, the output end of the first low-voltage power supply is used to connect to the low-voltage load through a load switch; the output end of the second low-voltage power supply is used to connect to the low-voltage load through a load switch.

[0067] In this embodiment, both the first low-voltage power supply and the second low-voltage power supply can be used to supply power to the low-voltage load. Optionally, the load switch can be a metal-oxide-semiconductor field-effect transistor (MOS) or other switch elements.

[0068] In some embodiments, the output end of the first low-voltage power supply is used to connect to the first end of the ADCU; the output end of the second low-voltage power supply is used to connect to the second end of the ADCU.

[0069] In this embodiment, the first low-voltage power supply and the second low-voltage power supply jointly power the ADCU, which can meet the power supply requirements of ASIL C and ASIL D of autonomous driving vehicles. The first low-voltage power supply and the second low-voltage power supply separately power the ADCU, which can meet the power supply requirements of ASIL A and ASIL B of vehicles, that is, downgraded driving.

[0070] In some embodiments, the system further includes a plurality of BMSs; each BMS is used to supervise a battery pack of the power battery.

[0071] Specifically, multiple BMSs independently monitor the battery status of the corresponding battery packs. When multiple BMSs monitor the voltage of the battery packs, they will determine whether the voltages of the multiple battery packs are balanced. If not, they can actively balance the voltages of the multiple battery packs by shutting down the voltage output of the circuit with lower voltage, thereby reducing the risk of reducing the available energy of the battery packs.

[0072] In some embodiments, the system further includes a plurality of pre-charging circuits; a battery pack of the power battery is connected to the DCDC via a pre-charging circuit.

[0073] In this embodiment, a pre-charging circuit is set up to eliminate the voltage shock generated when the power equipment is started, reduce the harm of the current shock, thereby avoiding damage to the equipment, extending the service life of the power equipment, improving the system stability, and ensuring the stable operation of the system and the safe use of the power equipment.

[0074] The present application also provides a vehicle, comprising any one of the low-voltage power supply systems in the aforementioned embodiments.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A low voltage power supply system, characterized in that: The system comprises: a first low-voltage redundant power supply circuit, a second low-voltage redundant power supply circuit and a third low-voltage redundant power supply circuit; The first low-voltage redundant power supply circuit, the second low-voltage redundant power supply circuit and the third low-voltage redundant power supply circuit respectively include a battery pack of a power battery and a DC voltage converter, the input end of the DC voltage converter is connected to the output end of a battery pack of the power battery, and the voltages of the multiple battery packs of the power battery are equal; The output ends of the DC voltage converters in the first low-voltage redundant power supply circuit and the second low-voltage redundant power supply circuit are both connected to the input end of the first low-voltage power supply; The output end of the DC voltage converter in the third low-voltage redundant power supply circuit is connected to the input end of the second low-voltage power supply; The output end of the first low-voltage power supply and the output end of the second low-voltage power supply are used to connect a low-voltage load.

2. The low voltage power supply system according to claim 1, characterized in that: The functional safety integrity level of the DC voltage converter in the first low-voltage redundant power supply circuit and the second low-voltage redundant power supply circuit is Class A; The functional safety integrity level of the DC voltage converter in the third low-voltage redundant power supply circuit is Class B.

3. The low voltage power supply system according to claim 1, characterized in that: The system further comprises: a fourth low voltage redundant power supply circuit; The fourth low-voltage redundant power supply circuit includes a battery pack of a power battery and a DC voltage converter; The output end of the DC voltage converter in the fourth low-voltage redundant power supply circuit is connected to the input end of the second low-voltage power supply.

4. The low voltage power supply system according to claim 3, characterized in that: The functional safety integrity levels of the DC voltage converters in the first low-voltage redundant power supply circuit, the second low-voltage redundant power supply circuit, the third low-voltage redundant power supply circuit and the fourth low-voltage redundant power supply circuit are all Class A.

5. The low voltage power supply system according to claim 2 or 4, characterized in that: The functional safety integrity level of the first low-voltage power supply and the second low-voltage power supply are both Class B.

6. The low voltage power supply system according to claim 2 or 4, characterized in that: The output end of the first low-voltage power supply is used to connect to a low-voltage load through a load switch; The output end of the second low-voltage power supply is used to be connected to a low-voltage load through a load switch.

7. The low voltage power supply system according to claim 2 or 4, characterized in that: The output end of the first low-voltage power supply is used to connect to the first end of the automatic driving controller; The output end of the second low-voltage power supply is used to connect to the second end of the automatic driving controller.

8. The low voltage power supply system according to claim 1 or 3, characterized in that: The system also includes a plurality of battery management systems; Each of the battery management systems is used to supervise a battery pack of the power battery.

9. The low voltage power supply system according to claim 1 or 3, characterized in that: The system also includes a plurality of pre-charging circuits; A battery pack of the power battery is connected to the DC voltage converter via a pre-charging circuit.

10. A vehicle, characterized in that: The vehicle comprises the low-voltage power supply system according to any one of claims 1-9.

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