New energy vehicle and integrated low-voltage system thereof

Abstract

The application relates to the field of new energy vehicles, and discloses a new energy vehicle and an integrated low-voltage system thereof, wherein a high-voltage side of integrated DCDC is connected with a power battery, high-voltage electricity of the power battery pack is converted into low-voltage electricity; a vehicle control unit, a charging control unit and a battery management system are connected with the integrated DCDC through CAN communication / hard-wire enabling connection, wherein the battery management system is used to monitor whether information such as a working state, an electricity quantity and a voltage of the power battery is normal, to realize state monitoring and management of the power battery; in the design method, the battery management system participates in power-on and power-off control of the integrated DCDC, so as to realize low-voltage electricity demand when special functions (such as wake-up monitoring) of the power battery system are realized.

Description

Technical Field

[0001] This invention belongs to the field of new energy vehicles, specifically relating to a new energy vehicle and its integrated low-voltage system. Background Technology

[0002] In new energy vehicles, the power supply for low-voltage devices (such as instruments, lights, and intelligent driving ECUs) and the control power supply for high-voltage components (such as motor controllers and battery control units) are all low-voltage. The vehicle's low-voltage power supply is typically provided by a low-voltage battery and a DC-DC converter (which converts the high voltage of the power battery to low voltage). The DC-DC converter, also known as a DC-DC voltage converter, is responsible for converting the high voltage of the power battery pack into low voltage to provide power to the 12V or 24V low-voltage battery and low-voltage loads. A common power supply topology is that the DC-DC converter and the battery are connected in parallel. When the DC-DC converter is working, it supplies low-voltage power to the entire vehicle on one hand, and replenishes the battery on the other. The battery, as the vehicle's low-voltage energy storage unit, can regulate the output voltage of the DC-DC converter and can also provide emergency power to the vehicle briefly after the DC-DC converter stops operating.

[0003] However, the increasing demands for vehicle safety and intelligence have placed greater emphasis on the low-voltage power supply system. This includes features such as timed battery activation after vehicle power loss, scheduled air conditioning activation, and delayed power-off of critical vehicle components. The low-voltage power supply system needs to intelligently activate on demand when the vehicle is powered off, while simultaneously preventing energy waste from conventional loads (such as lights and playback devices) during low-voltage power supply for these special functions.

[0004] To prevent safety incidents such as fires, power battery systems need to periodically perform self-checks on the battery status when the vehicle is powered off. This is mostly achieved by a built-in high-voltage to low-voltage DC-DC converter in the battery. Furthermore, in vehicle applications, depending on the power requirements of the components, more than one high-voltage to low-voltage DC-DC converter may be installed to supply power to the corresponding loads in the vehicle when it is powered on.

[0005] like Figure 1 As shown, the current low-voltage power supply configuration for vehicles is as follows: the air conditioning system typically has a dedicated air conditioning DC-DC converter, which supplies power to the internal fan and water pump via the air conditioning panel's start command; the vehicle's driving system has a dedicated vehicle DC-DC converter, which supplies power to the vehicle load and battery via vehicle control messages / hardwired enable; and the battery management system has a dedicated battery monitoring DC-DC converter, which supplies power to the battery management system via charging control messages / hardwired enable. Therefore, the number of DC-DC converters required for vehicle functionality is large, and their functions are distributed across multiple systems.

[0006] The low-voltage power supply of the whole vehicle is not intelligent enough. After the driver turns off the vehicle and disconnects the power, some components need to work with a delay, making it difficult to achieve power supply. In the field of commercial vehicles, vehicles are equipped with low-voltage mechanical switches as standard. After the vehicle is powered off, the low-voltage battery will be completely isolated from the vehicle's low-voltage system, which will cause the components to lose their delayed power supply function and cannot respond to the monitoring needs of individual loads (such as monitoring hosts) after the vehicle stops. Summary of the Invention

[0007] This invention provides a new energy vehicle and its integrated low-voltage system to solve the problems of the dispersed number and functions of DC-DC converters in the vehicle and the low intelligence of the vehicle's low-voltage power supply in the prior art.

[0008] To solve the above-mentioned technical problems, the technical solutions included in this invention and their corresponding beneficial effects are as follows:

[0009] This invention provides a solution for an integrated low-voltage system for new energy vehicles, including a DC-DC converter and a low-voltage battery. The high-voltage side of the DC-DC converter is used to connect to the power battery. The low-voltage side of the DC-DC converter is connected to a conventional low-voltage load that does not require power when the vehicle is off, and also to a special low-voltage load that requires power when the vehicle's main ignition switch is off, via a normally open contact of a first relay. The low-voltage battery is connected to the conventional low-voltage load via a normally open contact of a second relay and a normally open contact of the first relay, and also to the special low-voltage load via a normally open contact of the second relay. When the vehicle's main ignition switch is turned on, the normally open contacts of the first and second relays close.

[0010] The beneficial effects of the above technical solution are as follows: For special low-voltage loads that require power supply when the vehicle's main ignition switch is off, the control unit of the low-voltage system sends different control messages or different hard-wired enable signals to control the start and stop of different low-voltage systems; while the first relay is only closed after the vehicle is powered on and is in an open state at other times, it can isolate low-voltage power in special scenarios such as battery timed wake-up, plug-in charging, and remote scheduled air conditioning heating, to avoid powering the vehicle's regular loads after the DC-DC converter is started, and to avoid wasting energy by working unrelated low-voltage loads.

[0011] Furthermore, when the vehicle is powered on or a remote low-voltage load start command is remotely scheduled, the DC-DC converter is enabled to enter the working state via vehicle control messages or hard-wired enable.

[0012] In scenarios where remote reservation of air conditioning heating is possible, low-voltage electricity is isolated and will not supply power to the vehicle's regular loads, thus avoiding the waste of energy caused by unrelated low-voltage loads.

[0013] Furthermore, when the vehicle is detected to be in plug-in charging mode, the DC-DC converter is put into operation via charging control message or influence enable.

[0014] It can isolate low-voltage electricity when the vehicle is plugged in for charging, and will not supply power to the vehicle's regular loads, thus avoiding the waste of energy caused by unrelated low-voltage loads.

[0015] Furthermore, when the wake-up time required by the wake-up command issued by the battery management system to the DCDC is completed, the DCDC converter starts up and enters the working state; when the following conditions are met, the DCDC converter enters the shutdown state: the vehicle control message or hard-wired enable turns the DCDC converter off, the battery management system allows power down, and the charging control message or influence enable turns the DCDC converter off.

[0016] It can isolate low-voltage power in scenarios where the battery is scheduled to wake up, and will not supply power to the vehicle's regular loads, thus avoiding the waste of power by unrelated low-voltage loads.

[0017] Furthermore, the low-voltage side of the DC-DC converter is connected to each of the special low-voltage loads one by one through corresponding relays.

[0018] When the vehicle is powered off, it is not necessary to wake up all low-voltage devices; only the corresponding special voltage load needs to be woken up via a relay.

[0019] This invention also provides a solution for an integrated low-voltage system for new energy vehicles, including a DC-DC converter and a low-voltage battery. The high-voltage side of the DC-DC converter is used to connect to the power battery; the low-voltage side of the DC-DC converter is connected to the input terminal of a smart power distribution box; the low-voltage battery is also connected to the input terminal of the smart power distribution box; the smart power distribution box has output terminals that are connected one-to-one with each specific low-voltage load, and a controllable switch is provided in the power distribution box from the input terminal to each output terminal; the specific low-voltage load is a low-voltage load that requires power when the vehicle's main ignition switch is off.

[0020] The beneficial effects of the above technical solution are as follows: The vehicle controller (VCU) and other associated ECUs control the intelligent power distribution box to control the on / off of each load branch through controllable switches. In scenarios such as battery timed wake-up, plug-in charging, and remote scheduled air conditioning heating, only associated components are powered, and unrelated branches are not powered. This avoids powering the vehicle's regular loads after the DC-DC converter is started, and avoids wasting energy by working unrelated low-voltage loads.

[0021] Furthermore, when the vehicle is powered on or a remote low-voltage load start command is remotely scheduled, the DC-DC converter is enabled to enter the working state via vehicle control messages or hard-wired enable.

[0022] In scenarios where remote air conditioning heating can be scheduled, power is supplied only to related components, and unrelated branches are not powered. This avoids powering the vehicle's regular loads after the DC-DC converter is started, and avoids wasting energy by operating unrelated low-voltage loads.

[0023] Furthermore, when the vehicle is detected to be in plug-in charging mode, the DC-DC converter is put into operation via charging control message or influence enable.

[0024] It enables the system to supply power only to related components when the vehicle is plugged in for charging, while unrelated branches are not powered. This avoids the DC-DC converter from supplying power to the vehicle's regular loads after startup, and prevents unrelated low-voltage loads from wasting energy.

[0025] Furthermore, when the wake-up time required by the wake-up command issued by the battery management system to the DCDC is completed, the DCDC converter starts up and enters the working state; when the following conditions are met, the DCDC converter enters the shutdown state: the vehicle control message or hard-wired enable turns the DCDC converter off, the battery management system allows power down, and the charging control message or influence enable turns the DCDC converter off.

[0026] It can power only related components in the scenario of battery timed wake-up, and not power unrelated branches, to avoid powering the vehicle's regular load after the DC-DC converter starts, and to avoid wasting power on unrelated low-voltage loads.

[0027] The present invention also provides a solution for new energy vehicles, including any one of the two new energy vehicle integrated low-voltage systems described above.

[0028] The beneficial effects of the above technical solution are as follows: The vehicle utilizes an integrated DC-DC converter, which sends different control messages or hard-wired enable signals through the low-voltage system control unit to control the start-up and shutdown of different low-voltage systems, thus meeting the power needs of all loads under all operating conditions and in all scenarios. Compared to the dedicated DC-DC converters with different components in existing technologies, the integrated DC-DC converter of this invention eliminates other redundant DC-DC converters in the vehicle, achieving weight reduction and cost reduction for the entire vehicle. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the low-voltage power supply for a vehicle in the existing technology;

[0030] Figure 2 This is a schematic diagram of the vehicle's low-voltage power supply in this invention;

[0031] Figure 3 This invention employs a low-voltage integration method and power supply logic diagram (using a conventional electrical box);

[0032] Figure 4 This invention employs a low-voltage integration method and power supply logic diagram (using a smart power distribution box);

[0033] Figure 5 This is a schematic diagram of the power-on logic of the integrated DC-DC converter in this invention;

[0034] Figure 6 This is a schematic diagram of the power-down logic of the integrated DC-DC converter in this invention. Detailed Implementation

[0035] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0036] System Implementation Example 1:

[0037] The basic concept of this invention is to use an integrated DC-DC converter to meet the low-voltage power demand of all loads in the vehicle under all operating conditions and scenarios, thereby eliminating other redundant DC-DC converters in the vehicle and achieving weight reduction and cost reduction. The integrated DC-DC converter is a device that converts the high-voltage power of the power battery into the low-voltage power of the vehicle system (generally 24V or 12V). The DC-DC start-up and shutdown can be achieved through different hard-wired enable and message control. That is, each control unit will send an enable valid signal when it needs the DC-DC to work, and send an enable invalid signal when it needs to shut down the DC-DC. After the enable is invalidated, the DC-DC stops.

[0038] like Figure 2 As shown, the high-voltage side of the integrated DC-DC converter is connected to the power battery (vehicle high-voltage power supply), converting the high-voltage electricity of the power battery pack into low-voltage electricity. The vehicle control unit, charging control unit, and battery management system are connected to the integrated DC-DC converter via CAN communication / hardwire enable. The battery management system is used to monitor whether the power battery's working status, charge, voltage, and other information are normal, realizing the status monitoring and management of the power battery. In the design method of this case, the battery management system participates in the power-on and power-off control of the integrated DC-DC converter to meet the low-voltage power demand of the power battery system during special functions (such as wake-up monitoring).

[0039] The low-voltage side of the integrated DC-DC converter is connected to the battery management system, and also to the air conditioning fan / water pump and the vehicle load. The air conditioning fan / water pump and the vehicle load are also connected to the positive terminal of the 24V battery via a handle switch K0 (for buses with a length of 6m or more, the national standard requires the addition of a battery disconnection device; for vehicles under 6m (including passenger cars), this requirement does not apply; this handle switch is manually rotated or pressed to switch the battery and the vehicle on and off) and the negative terminal of the battery is grounded. When the DC-DC converter is not working, the battery supplies power to the vehicle's low-voltage system; when the DC-DC converter is working, it supplies power to the entire vehicle. The battery and the DC-DC converter are connected in parallel to stabilize the output voltage of the DC-DC converter.

[0040] like Figure 3The integrated low-voltage system for new energy vehicles shown (using a conventional power distribution box) includes a DC-DC converter and a low-voltage battery. The high-voltage side of the DC-DC converter is used to connect to the power battery. The low-voltage side of the DC-DC converter is connected to traditional low-voltage loads (such as instruments, interior lights, exterior headlights, road signs, etc., traditional equipment not closely related to new energy vehicles) that do not require power after the vehicle is turned off, through the normally open contact of the first relay K2. It is also connected to special low-voltage loads that require power when the vehicle's main ignition switch is off (such as battery system wake-up self-test when the vehicle is parked for a long time, remote scheduled start of the vehicle's air conditioning, and delayed power-off of the BMS). The low-voltage battery is connected to the traditional low-voltage loads through the normally open contacts of the second relay K1 and the first relay K2, and is also connected to the special low-voltage loads through the normally open contact of the second relay. When the vehicle's main ignition switch is turned on, the normally open contacts of the first and second relays close.

[0041] The second relay K1 is controlled by the ignition switch and serves as the main ignition relay for the entire vehicle. The first relay K2 serves as the relay for the vehicle's conventional loads. The conventional load relay K2 is closed only after the vehicle is powered on and is open at other times. It can isolate low-voltage power in special scenarios such as battery timed wake-up, plug-in charging, and remote scheduled air conditioning heating, to prevent the DC-DC converter from supplying power to the vehicle's conventional loads after startup and to avoid wasting energy by unrelated low-voltage loads.

[0042] Relays and fuses are used as devices for the power distribution of each load unit. A relay is a device that receives control signals and turns the relay on or off. In the diagram, the control signal for the main ignition relay K1 is the vehicle's ignition switch, which is located in the driver's cab. When the ignition switch is pressed, the main ignition relay K1 closes, connecting the vehicle to the low-voltage battery. The conventional load relay K2 supplies power to the vehicle's conventional electrical equipment. A fuse is a device for circuit protection.

[0043] System Implementation Example 2:

[0044] Unlike System Implementation Example 1, the integrated low-voltage system for new energy vehicles in this embodiment uses a smart power distribution box. For example... Figure 4 The integrated low-voltage system (using a smart power distribution box) shown is for new energy vehicles. Figure 3 The integrated low-voltage system for new energy vehicles shown (using a conventional power distribution box): As for further optimization, Figure 4 Replace with smart distribution box Figure 3In a conventional power distribution box, the controllable switches in the intelligent power distribution box use semiconductor devices such as IGBTs and MOSFETs as load power distribution control devices. These semiconductor switches are controlled by the vehicle control unit (VCU) and other ECU control units, turning the semiconductor devices on and off according to the vehicle's operating conditions to control the power supply to the corresponding load branch. This low-voltage system includes a DC-DC converter and a low-voltage battery. The high-voltage side of the DC-DC converter is connected to the power battery; the low-voltage side of the DC-DC converter is connected to the input terminal of the intelligent power distribution box; the input terminal of the intelligent power distribution box is also connected to the low-voltage battery; the intelligent power distribution box includes several controllable switches; the output terminal of the intelligent power distribution box is connected, one-to-one, via controllable switches to special low-voltage loads that require power when the vehicle's main ignition switch is off.

[0045] The vehicle control unit (VCU) and other associated ECUs control the on / off switching of each load branch of the intelligent power distribution box. In scenarios such as battery timed wake-up, plug-in charging, and remote scheduled air conditioning heating, power is only supplied to associated components, and power is not supplied to unrelated branches. This avoids powering the vehicle's regular loads after the DC-DC converter is started, and avoids wasting energy by working unrelated low-voltage loads.

[0046] like Figure 5 As shown, the startup logic of the integrated DC-DC converter is as follows: when the vehicle receives a power-on operation command or a remote scheduled electrical component start command (the vehicle control provides a message or hard-wired work enable), or the vehicle is in a charging state (the charging pile provides a message or hard-wired work enable), or the wake-up time required by the internally recorded battery management system is completed, the DC-DC converter can enter the working state and start outputting to the outside world when any of the above conditions are met.

[0047] like Figure 6 As shown, the shutdown logic of the integrated DC-DC converter is as follows: When the vehicle sends a power-down command to the DC-DC converter (the vehicle control does not provide a message or hard-wired operation enable, so this enable is invalid), and the vehicle is not in a plug-in charging state (the charging pile does not provide a message or hard-wired operation enable, so this enable is invalid), and the internally recorded battery management system allows low-voltage power-down, the DC-DC converter can enter the shutdown state and stop outputting.

[0048] The integrated DC-DC converter of this invention can achieve the following functions:

[0049] ① The power supply meets the low-voltage power requirements of the entire vehicle, including power for air conditioning, battery, and various low-voltage water pumps or fans. The entire vehicle only needs this one DC-DC converter. The integrated DC-DC converter is directly connected to the high-voltage power of the power battery without any switches or contactors in between. It has a constant power module inside, which can convert the high-voltage power of the battery into low-voltage power for the control logic section. At the same time, the constant power module has a storage module and a timing module, which can store the vehicle's timed operation commands to start the output of the DC-DC converter.

[0050] ② It can respond to message or hard-wired enable control requirements of the vehicle control unit (VCU) and can start or close the DC-DC converter according to the instructions.

[0051] ③ It can respond to the message or hard-wired enable control requirements of the battery management system (BMS) and has the ability to store BMS instructions (such as the BMS issuing an instruction to start the DC-DC converter for battery balancing 1 hour after the vehicle is powered off). The DC-DC converter reads the BMS instruction, stores it, and has a timing module. It starts up after the timing time expires and can shut down according to the BMS shutdown instruction.

[0052] ④ It can respond to the charging gun's message or hard-wired enable control requirements, identify the charging status, and turn on and off according to the enable control command.

[0053] ⑤ The integrated DC-DC converter is directly connected to the high-voltage power of the power battery, without any switches or contactors in between; the power meets the low-voltage power needs of the entire vehicle, including the power for air conditioning, battery, and various low-voltage water pumps or fans. The entire vehicle only needs this one DC-DC converter.

[0054] ⑥ An integrated DC-DC converter can be a standalone component or integrated as a functional module with other modules of the vehicle.

[0055] ⑦ For buses of 6m and above, even if the battery handle switch K0 is turned off, emergency needs such as battery monitoring and remote reservation can still be met. The low-voltage power consumption of the whole vehicle is not restricted by factors such as battery depletion or handle switch disconnection.

[0056] Examples of new energy vehicles:

[0057] One type of new energy vehicle of the present invention includes any one of the two types of integrated low-voltage systems for new energy vehicles as described above.

[0058] The specific embodiments of the present invention have been given above, but the present invention is not limited to the described embodiments. Under the concept given by the present invention, the technical means in the above embodiments can be changed, replaced, or modified in a way that is easy for those skilled in the art to conceive of, and the effect is basically the same as the corresponding technical means in the present invention, and the purpose of the invention is also basically the same. The technical solution formed in this way is a fine-tuning of the above embodiments, and such technical solution still falls within the protection scope of the present invention.

Claims

1. A new energy vehicle integrated low-voltage system, characterized in that, The system includes a DC-DC converter and a low-voltage battery. The high-voltage side of the DC-DC converter is connected to the power battery. The low-voltage side of the DC-DC converter is connected to conventional low-voltage loads that do not require power when the vehicle is off via a normally open contact of a first relay. The low-voltage side of the DC-DC converter is also connected to special low-voltage loads that require power when the vehicle's main ignition switch is off via corresponding relays. These special low-voltage loads include loads that require power when the vehicle is parked for an extended period, such as those used for battery system wake-up self-test, remote scheduled start of the vehicle's air conditioning, and loads that require power after a delayed power-off by the BMS. The low-voltage battery is connected to the conventional low-voltage loads via normally open contacts of a second relay and a normally open contact of the first relay, and is also connected to the special low-voltage loads via a normally open contact of the second relay. The first relay is closed only when the vehicle is powered on, and is open at other times. When the vehicle's main ignition switch is turned on, the normally open contacts of the first and second relays close, connecting the low-voltage battery to the vehicle. When the vehicle receives a power-on operation or a remotely scheduled low-voltage load start command, the DC-DC converter is enabled to enter the working state via vehicle control messages or hard-wired enable. When the vehicle is detected to be in plug-in charging mode, the DC-DC converter is enabled to enter the working state via charging control messages or hard-wired enable. After the wake-up time required by the wake-up command issued by the battery management system to the DC-DC converter is completed, the DC-DC converter starts up and enters the working state. The DC-DC converter enters the shutdown state when all of the following conditions are met: the DC-DC converter is shut down via vehicle control messages or hard-wired enable, the battery management system allows power-down, and the DC-DC converter is shut down via charging control messages or hard-wired enable.

2. The new energy vehicle integrated low-voltage system according to claim 1, characterized in that, A handle switch is also connected in series between the battery and the normally open contact of the second relay.

3. The new energy vehicle integrated low-voltage system according to claim 2, characterized in that, The low-voltage side of the DC-DC converter is connected to special low-voltage loads that require power when the vehicle's main ignition switch is off, through corresponding fuses and relays.

4. The new energy vehicle integrated low-voltage system according to claim 3, characterized in that, When the ignition switch is pressed, the second relay, which acts as the main ignition relay K1, closes.

5. The new energy vehicle integrated low-voltage system according to claim 1, characterized in that, The traditional low-voltage loads include instruments, interior lights, exterior headlights, and road signs.

6. A new energy vehicle, characterized in that, Including the integrated low-voltage system for new energy vehicles as described in claim 1.

7. The new energy vehicle according to claim 6, characterized in that, A handle switch is also connected in series between the battery and the normally open contact of the second relay.

8. The new energy vehicle according to claim 7, characterized in that, The low-voltage side of the DC-DC converter is connected to special low-voltage loads that require power when the vehicle's main ignition switch is off, through corresponding fuses and relays.

9. The new energy vehicle according to claim 8, characterized in that, When the ignition switch is pressed, the second relay, which acts as the main ignition relay K1, closes.

10. The new energy vehicle of claim 6, wherein, The traditional low-voltage loads include instruments, interior lights, exterior headlights, and road signs.

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