Vehicle starting redundancy power supply system and vehicle starting redundancy power supply method

Abstract

The application provides a vehicle starting redundant power supply system and a vehicle starting redundant power supply method, and belongs to the technical field of vehicle low-voltage power supply management. The system comprises a lead-acid battery, a lithium battery, a low-voltage load bus, a first switch, a second switch, a voltage detection module and a local controller. The lead-acid battery is connected with the low-voltage load bus through the first switch and connected with the local controller through the voltage detection module. The lithium battery is connected with the low-voltage load bus through the second switch and also connected with the local controller. The local controller is used for controlling the first switch to be turned off and the second switch to be turned on when the voltage of the lead-acid battery collected by the voltage detection module is lower than a preset first threshold value for N times in succession, and N is greater than or equal to 2. The application can solve the technical problem that the prior art has a high cost when dealing with the voltage drop of the lead-acid battery.

Description

Technical Field

[0001] This invention relates to the field of vehicle low-voltage power management technology, specifically to a vehicle starting redundant power supply system and a vehicle starting redundant power supply method. Background Technology

[0002] The automotive low-voltage system has a rated voltage of 12V and is responsible for powering key components such as the ECU (Electronic Control Unit), instruments, lighting, sensors, and actuators. Traditional solutions use a single lead-acid battery as the power source, with an alternator driven by the engine supplementing the power during operation.

[0003] When a vehicle starts, the starter motor requires a large current to drive the engine crankshaft to rotate. This current is entirely powered by the lead-acid battery. Lead-acid batteries have internal resistance, and under high current, a significant voltage drop occurs at their terminals. At the moment of vehicle startup, the high current from the starter motor pulls down the lead-acid battery's terminal voltage, leading to insufficient power supply to low-voltage components such as the ECU and instrument clusters, or even causing them to reset.

[0004] Especially for vehicles equipped with automatic start-stop functions, the frequency of starting has increased from the traditional 3-5 times per day to dozens or even hundreds of times. Lead-acid batteries are frequently subjected to high current surges, accelerating aging, increasing internal resistance, and exacerbating voltage drop problems.

[0005] To address these issues, traditional solutions include increasing the capacity of lead-acid capacitors (high cost and weight), using parallel supercapacitors (high cost and large size), or employing a dual lead-acid architecture (lacking intelligent management and causing mutual interference). Existing solutions are costly. Summary of the Invention

[0006] In view of this, it is necessary to provide a vehicle starting redundant power supply system and a vehicle starting redundant power supply method to solve the technical problem of high cost in the existing technology when dealing with the voltage drop problem of lead-acid batteries.

[0007] To address the aforementioned problems, in a first aspect, the present invention provides a redundant power supply system for vehicle starting, comprising: a lead-acid battery, a lithium battery, a low-voltage load bus, a first switch, a second switch, a voltage detection module, and a local controller. The lead-acid battery is connected to the low-voltage load bus via the first switch and to the local controller via the voltage detection module; The lithium battery is connected to the low-voltage load bus via the second switch, and is also connected to the local controller; The local controller is used to control the first switch to open and the second switch to close when the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, where N≥2.

[0008] In one possible implementation, the vehicle starts a redundant power supply system, which further includes: a third switch; the lithium battery is also connected to an extended low-voltage load via the third switch; the extended low-voltage load includes: a security system, a T-Box, and monitoring equipment; The local controller is also used to control the closing of the third switch when the vehicle is stopped.

[0009] In one possible implementation, the first switch, the second switch, and the third switch are all MOSFETs or relays.

[0010] In one possible implementation, if the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, controlling the first switch to open and controlling the second switch to close includes: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, and the lithium battery voltage collected by the voltage detection module is greater than the sum of the low-voltage load bus voltage and the preset bias voltage, the first switch is controlled to open and the second switch is controlled to close.

[0011] In one possible implementation, the local controller is further configured to control the first switch to close and control the second switch to open after a preset fixed delay time has elapsed and the lead-acid battery voltage has recovered to a value higher than a preset second threshold. The preset second threshold is greater than the preset first threshold.

[0012] In one possible implementation, the local controller is further configured to determine that the lead-acid battery has malfunctioned after the second switch has been closed and the lead-acid battery voltage has not recovered to a level higher than a preset second threshold time multiple times.

[0013] In a second aspect, the present invention also provides a vehicle including the vehicle starting redundant power supply system described in any of the above claims.

[0014] Thirdly, the present invention also provides a vehicle starting redundant power supply method, the method being applied to the vehicle starting redundant power supply system described in any of the above claims, the method comprising: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, the local controller controls the first switch to open and controls the second switch to close, where N≥2.

[0015] In one possible implementation, if the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, the local controller controls the first switch to open and the second switch to close, including: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, and the lithium battery voltage collected by the voltage detection module is greater than the sum of the low-voltage load bus voltage and the preset bias voltage, the local controller controls the first switch to open and controls the second switch to close.

[0016] In one possible implementation, the vehicle startup redundant power supply method further includes: After the second switch is closed and merged for a preset fixed delay time, and the lead-acid battery voltage recovers to a level higher than a preset second threshold, the local controller controls the first switch to close and merge to control the second switch to open. The preset second threshold is greater than the preset first threshold.

[0017] The beneficial effects of adopting the above implementation method are as follows: The vehicle starting redundant power supply system and vehicle starting redundant power supply method provided by the present invention include a lead-acid battery, a lithium battery, a low-voltage load bus, a first switch, a second switch, a voltage detection module, and a local controller; the lead-acid battery is connected to the low-voltage load bus through the first switch and to the local controller through the voltage detection module; the lithium battery is connected to the low-voltage load bus through the second switch and is also connected to the local controller; the local controller is used to control the first switch to open and control the second switch to close when the voltage of the lead-acid battery collected by the voltage detection module is lower than a preset first threshold N times consecutively, where N≥2.

[0018] In this system, a lead-acid battery serves as the main battery during vehicle startup, while a lithium battery acts as a redundant battery. When the voltage of the lead-acid battery collected by the voltage detection module is consistently below a preset first threshold for N consecutive times, it can be determined that the current operating condition is a startup voltage drop condition. At this point, the local controller switches power supply, achieving local autonomous switching without waiting for a CAN (Controller Area Network) response from the vehicle controller. Therefore, the response scheme provided by this invention is faster. Furthermore, the solution provided by this invention only requires adding one switching branch and one local controller, significantly reducing costs. It effectively solves the low-voltage system anomaly caused by the voltage drop of the lead-acid battery during startup, achieving millisecond-level seamless switching during vehicle startup. This addresses the high cost of existing technologies in handling lead-acid battery voltage drops. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic block diagram of an embodiment of the vehicle starting redundant power supply system provided by the present invention; Figure 2 This is a flowchart of one embodiment of the vehicle startup redundant power supply method provided by the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] In the description of the embodiments of this application, unless otherwise stated, "a plurality of" means two or more.

[0023] In this embodiment of the invention, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, apparatus, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such process, method, product or device.

[0024] The naming or numbering of steps in the embodiments of the present invention does not mean that the steps in the method flow must be executed in the time / logical order indicated by the naming or numbering. The execution order of the named or numbered process steps can be changed according to the technical purpose to be achieved, as long as the same or similar technical effect can be achieved.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] This invention provides a vehicle starting redundant power supply system and a vehicle starting redundant power supply method, which are described below.

[0027] like Figure 1 As shown, the present invention provides a vehicle starting redundant power supply system, including: a lead-acid battery, a lithium battery, a low-voltage load bus, a first switch, a second switch, a voltage detection module, and a local controller; The lead-acid battery is connected to the low-voltage load bus via the first switch and to the local controller via the voltage detection module; The lithium battery is connected to the low-voltage load bus via the second switch, and is also connected to the local controller; The local controller is used to control the first switch to open and the second switch to close when the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, where N≥2.

[0028] It is understandable that the lead-acid battery serves as the main battery during vehicle startup, while the lithium battery acts as a redundant battery. When the voltage of the lead-acid battery collected by the voltage detection module is lower than a preset first threshold for N consecutive times, it can be determined that the current operating condition is a startup drop condition. At this time, the local controller switches the power supply, realizing local autonomous switching without waiting for the CAN (Controller Area Network) response from the vehicle controller. Therefore, the response scheme provided by this invention is faster. Moreover, the solution provided by this invention only requires adding a switching branch and a local controller, greatly reducing costs, and can solve the low-voltage system anomaly caused by the lead-acid voltage drop at the moment of startup, achieving millisecond-level seamless switching at the moment of vehicle startup.

[0029] In some embodiments, the vehicle starts a redundant power supply system, which further includes: a third switch; the lithium battery is also connected to an extended low-voltage load through the third switch; the extended low-voltage load includes: a security system, a T-Box, and monitoring equipment; The local controller is also used to control the closing of the third switch when the vehicle is stopped.

[0030] Understandably, the third switch branch is independently controlled and powered by the lithium battery to supply power to the extended low-voltage load. It can be controlled by local controller commands to continuously power the security system, T-Box, remote monitoring, etc. when the vehicle is stopped, without affecting the main / standby switching function.

[0031] In some embodiments, the first switch, the second switch, and the third switch are all MOSFETs or relays.

[0032] It is understandable that relays are cheaper than MOSFETs, while MOSFETs have faster response and longer lifespan compared to relays.

[0033] In some embodiments, if the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, controlling the first switch to open and controlling the second switch to close includes: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, and the lithium battery voltage collected by the voltage detection module is greater than the sum of the low-voltage load bus voltage and the preset bias voltage, the first switch is controlled to open and the second switch is controlled to close.

[0034] Understandably, when the lead-acid terminal voltage is consistently below the first threshold after multiple consecutive samplings, a drop-out condition is triggered. In this case, the first switch needs to be opened and the second switch closed. To prevent backflow protection, before the second switch branch is turned on, the local controller checks whether the lithium battery terminal voltage is higher than the sum of the load bus voltage and the preset bias voltage. If the lithium battery terminal voltage is higher than the sum of the load bus voltage and the preset bias voltage, the check is passed, and the second switch branch can be turned on only after the check is passed. If the check fails, it indicates that the lithium battery voltage is insufficient to supply power, and the second switch branch is prohibited from being turned on, maintaining lead-acid power supply, and outputting a "low lithium battery voltage" fault signal to prevent the bus from backflowing and charging the lithium battery when the lithium battery voltage is insufficient.

[0035] In some embodiments, the local controller is further configured to control the first switch to close and control the second switch to open after a preset fixed delay time has elapsed and the lead-acid battery voltage has recovered to a value higher than a preset second threshold. The preset second threshold is greater than the preset first threshold.

[0036] Understandably, after the fixed delay time, the second switch branch is disconnected. If the lead-acid terminal voltage has recovered to a second threshold higher than the first threshold, the first switch branch is turned on to restore lead-acid power supply; if it has not recovered, lithium battery power supply continues and the timer restarts. The first and second thresholds form a hysteresis comparison to avoid frequent switching of the power supply path due to voltage fluctuations.

[0037] In some embodiments, the local controller is further configured to determine that the lead-acid battery has malfunctioned after the second switch is turned off and closed multiple times in succession for a preset fixed delay time, and the lead-acid battery voltage has not recovered to a level higher than a preset second threshold.

[0038] Understandably, if the lead-acid battery voltage fails to recover to the second threshold above the first threshold after multiple consecutive delays, the local controller determines that the lead-acid battery is faulty (such as severe depletion, abnormally increased internal resistance, or loose wiring). It maintains backup mode, continuously supplies power from the lithium battery, sends a "lead-acid voltage continuously abnormal" alarm signal to the vehicle, and initiates lithium battery power monitoring. If the lithium battery power is lower than the safety threshold, it gradually unloads non-critical loads to ensure power supply to critical systems.

[0039] The present invention also provides a vehicle including the vehicle starting redundant power supply system described in any of the preceding claims.

[0040] The present invention also provides a vehicle starting redundant power supply method, the method being applied to the vehicle starting redundant power supply system described in any of the above claims, the method comprising: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, the local controller controls the first switch to open and controls the second switch to close, where N≥2.

[0041] In some embodiments, if the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, the local controller controls the first switch to open and the second switch to close, including: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, and the lithium battery voltage collected by the voltage detection module is greater than the sum of the low-voltage load bus voltage and the preset bias voltage, the local controller controls the first switch to open and controls the second switch to close.

[0042] In some embodiments, the vehicle startup redundant power supply method further includes: After the second switch is closed and merged for a preset fixed delay time, and the lead-acid battery voltage recovers to a level higher than a preset second threshold, the local controller controls the first switch to close and merge to control the second switch to open. The preset second threshold is greater than the preset first threshold.

[0043] In summary, this invention solves the low-voltage system anomaly caused by the voltage drop of lead-acid batteries at startup with minimal incremental cost (only adding one switch branch + local controller), achieves millisecond-level seamless switching at the moment of vehicle startup, avoids frequent switching caused by voltage fluctuations, and extends the life of lead-acid batteries while realizing the energy buffer value of redundant batteries.

[0044] In some embodiments, the vehicle's redundant power supply system for starting includes a lead-acid main battery (i.e., a lead-acid battery), a lithium-ion redundant battery (i.e., a lithium-ion battery), a low-voltage load bus, a first MOS switch branch, a second MOS switch branch, a third MOS switch branch, a voltage detection module, and a local controller MCU. See Appendix. Figure 1 The system block diagram.

[0045] The lead-acid main battery is connected to the low-voltage load bus via the first MOS switch branch, while the lithium battery is connected to the low-voltage load bus via the second MOS switch branch and to the extended low-voltage load via the third MOS switch branch. The voltage detection module samples the lead-acid battery terminal voltage in real time, and the local controller independently controls the conduction and disconnection of the three MOS switch branches based on the sampled values.

[0046] The system monitors the lead-acid battery terminal voltage in real time through the local controller and autonomously decides to switch the power supply path based on the voltage status, without waiting for CAN commands from the vehicle controller.

[0047] like Figure 2 As shown, the specific control logic is as follows: Normal power supply: The first MOS branch (i.e., the first switch) is turned on, the second MOS branch (i.e., the second switch) is turned off, and the lead-acid battery supplies power to the low-voltage load bus; the voltage detection module continuously samples the voltage at the lead-acid terminal.

[0048] Initiating drop detection: When the lead-acid terminal voltage is continuously sampled below the first threshold multiple times, it is determined to be initiating drop detection.

[0049] Power supply switching: The local controller immediately disconnects the first MOS branch and connects the second MOS branch, switching to lithium battery power. The entire switching process is completed by local hardware, with a response time of less than 10ms.

[0050] Anti-reverse current protection: Before the second MOS branch is turned on, the local controller MCU checks whether the lithium battery terminal voltage is higher than the sum of the load bus voltage and the preset bias. It can only be turned on after the check passes. If the check fails, it indicates that the lithium battery voltage is insufficient to supply power, and the second MOS branch is prohibited from being turned on, maintaining lead-acid power supply, and an "insufficient lithium battery voltage" fault signal is output. This prevents the bus from reversing and charging the lithium battery when the lithium battery voltage is insufficient.

[0051] Fixed delay hold: After switching, the second MOS branch remains on for a fixed duration, covering the starter motor's operating cycle. During the delay, the lead-acid terminal voltage is continuously monitored, but no switching action is performed. The typical operating cycle of a vehicle starter motor is 1-2 seconds; the approximately 2-second delay ensures coverage of most starting scenarios, avoiding repeated switching before the starter is complete. This value is an empirically calibrated value and can be adjusted according to the vehicle model's starter motor power and engine displacement.

[0052] Power restoration: After a fixed delay, the second MOS branch is disconnected. If the lead-acid terminal voltage has recovered to a second threshold higher than the first threshold, the first MOS branch is turned on to restore lead-acid power supply; if it has not recovered, the lithium battery power supply continues and the timing restarts. The first and second thresholds form a hysteresis comparison to avoid frequent switching of the power supply path due to voltage fluctuations.

[0053] If the lead-acid battery voltage fails to recover after multiple consecutive delays, the local controller MCU determines that the lead-acid battery is faulty (such as severe depletion, abnormally increased internal resistance, or loose wiring). It maintains backup mode, continuously supplies power from the lithium battery, sends a "lead-acid voltage continuously abnormal" alarm signal to the vehicle, and initiates lithium battery power monitoring. If the lithium battery power is lower than the safety threshold, it gradually unloads non-critical loads to ensure power supply to critical systems.

[0054] Extended power supply: The third MOS branch (i.e. the third switch) is independently controlled and powered by the lithium battery to supply extended low-voltage loads. It is controlled by the local controller MCU or the vehicle CAN command and provides continuous power to security systems, T-Box, remote monitoring and other systems when the vehicle is stopped, without affecting the main and backup switching function.

[0055] Local fast switching mechanism: Local autonomous switching based on lead-acid terminal voltage detection eliminates the need to wait for a CAN response from the vehicle controller. If the total response time, including CAN communication and vehicle PDC (Power Control Module) processing, is too long, it may cause the ECU to reset during the transient process of a voltage drop at startup. This solution, however, offers a much faster response.

[0056] Fixed delay + hysteresis recovery strategy: A fixed time delay after switching ensures coverage of the entire startup process. During recovery, a hysteresis threshold higher than the drop threshold is used to avoid repeated switching when startup is not complete. If a single threshold is used, voltage fluctuations will cause the MOSFET to switch frequently and overheat and be damaged.

[0057] Pre-emptive judgment to prevent backflow: Before the second MOSFET is turned on, it is checked whether the lithium battery voltage is higher than the bus voltage plus the bias voltage. If so, the second MOSFET is turned on. If the lithium battery voltage is lower than the bus voltage plus the bias voltage, after the second MOSFET is turned on, the bus will reverse charge the lithium battery, causing the lithium battery to be passively charged. There is no current limit to the passive charging of the lithium battery, which may trigger the BMS (Battery Management System) protection or even thermal runaway, which will cause the lead-acid side to suddenly lose the load, the voltage rebound, and be mistakenly judged as "recovery".

[0058] This embodiment adopts a three-MOS branch independent architecture: It employs three independent MOS branch controls: lead-acid power supply, lithium battery backup, and lithium battery extension. These three independent branches enable fault isolation, ensuring that a single-circuit fault does not propagate. Furthermore, the extension branch can operate in parallel with primary / backup switching, enhancing system flexibility. Moreover, although all three branches share a lithium battery, the control logic is decoupled, reducing software complexity.

[0059] The vehicle starting redundant power supply system and vehicle starting redundant power supply method provided by the present invention have been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A redundant power supply system for vehicle starting, characterized in that, include: Lead-acid battery, lithium battery, low-voltage load bus, first switch, second switch, voltage detection module and local controller; The lead-acid battery is connected to the low-voltage load bus via the first switch and to the local controller via the voltage detection module; The lithium battery is connected to the low-voltage load bus via the second switch, and is also connected to the local controller; The local controller is used to control the first switch to open and the second switch to close when the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, where N≥2.

2. The vehicle starting redundant power supply system according to claim 1, characterized in that, Also includes: The third switch; The lithium battery is also connected to an extended low-voltage load via the third switch; The extended low-voltage load includes: security systems, T-Boxes, and monitoring equipment; The local controller is also used to control the closing of the third switch when the vehicle is stopped.

3. The vehicle starting redundant power supply system according to claim 2, characterized in that, The first switch, the second switch, and the third switch are all MOSFETs or relays.

4. The vehicle starting redundant power supply system according to claim 1, characterized in that, If the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, the system controls the first switch to open and the second switch to close, including: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, and the lithium battery voltage collected by the voltage detection module is greater than the sum of the low-voltage load bus voltage and the preset bias voltage, the first switch is controlled to open and the second switch is controlled to close.

5. The vehicle starting redundant power supply system according to claim 1, characterized in that, The local controller is further configured to control the first switch to close and control the second switch to open after a preset fixed delay time has elapsed and the lead-acid battery voltage has recovered to a value higher than a preset second threshold. The preset second threshold is greater than the preset first threshold.

6. The vehicle starting redundant power supply system according to claim 1, characterized in that, The local controller is further configured to determine that the lead-acid battery has malfunctioned if the second switch is closed and shut down repeatedly after a preset fixed delay time has elapsed and the lead-acid battery voltage has not recovered to a level higher than a preset second threshold.

7. A vehicle, characterized in that, Includes the vehicle starting redundant power supply system as described in any one of claims 1-6.

8. A method for redundant power supply for vehicle starting, characterized in that, The method is applied to the vehicle starting redundant power supply system according to any one of claims 1-6, and the method includes: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, the local controller controls the first switch to open and controls the second switch to close, where N≥2.

9. The vehicle starting redundant power supply method according to claim 8, characterized in that, If the lead-acid battery voltage collected by the voltage detection module is lower than a preset first threshold for N consecutive times, the local controller controls the first switch to open and the second switch to close, including: If the lead-acid battery voltage collected by the voltage detection module is lower than the preset first threshold for N consecutive times, and the lithium battery voltage collected by the voltage detection module is greater than the sum of the low-voltage load bus voltage and the preset bias voltage, the local controller controls the first switch to open and controls the second switch to close.

10. The vehicle starting redundant power supply method according to claim 8, characterized in that, Also includes: After the second switch is closed and merged for a preset fixed delay time, and the lead-acid battery voltage recovers to a level higher than a preset second threshold, the local controller controls the first switch to close and merge to control the second switch to open. The preset second threshold is greater than the preset first threshold.

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