Full-power downhill protection method and system for lithium battery of low-voltage new energy vehicle

Abstract

The invention discloses a full-charge downhill protection method and system for a lithium battery of a low-voltage new energy vehicle. The method comprises the following steps: acquiring the state of charge (SOC) of the lithium battery through a battery current protection plate; the vehicle speed detection module collects the driving speed and the accelerated speed; the gradient sensor detects whether the gradient is greater than 5% or less than 2%; the control module is combined with the information to judge that when SOC is larger than or equal to 95% and the gradient is larger than 5% or the vehicle speed exceeds the rated speed, an instruction is triggered to close the energy recovery function and the abrupt slope slow descent function, and an energy recovery circuit is cut off to prevent recoil current input. When the vehicle speed exceeds the rated speed or the acceleration is larger than 2 m / s, the active speed limiting module conducts a motor MOS tube to dissipate electric energy and synchronously triggers a sound-light alarm. And when SOC is detected to be smaller than or equal to 90% or the gradient is smaller than 2%, protection is automatically relieved, and normal driving is recovered. The lithium battery can be protected during full-power downhill, the protection plate is prevented from being broken down by recoil current, the hidden danger of thermal runaway is reduced, and the service life of the lithium battery is prolonged.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle control technology, specifically to a method and system for protecting low-voltage new energy vehicle lithium batteries when they are fully charged and going downhill. Background Technology

[0002] In today's new energy vehicle field, especially low-voltage new energy vehicles, lithium batteries, as a key energy storage component, have received considerable attention for their performance and safety. When a vehicle is on a long downhill slope in mountainous areas exceeding 10km, the energy recovery mechanism generates a recoil current. If the lithium battery is fully charged at this time, this recoil current will cause the lithium battery voltage to rise sharply and exceed the safety threshold. On the one hand, the strong recoil current can easily break down the overcurrent protection board of the lithium battery, exposing the lithium battery directly to a dangerous current environment; on the other hand, the excessively high current will cause a sharp increase in internal heat generation. When the temperature exceeds 80℃, the electrolyte will decompose, potentially triggering thermal runaway. Currently, most low-voltage new energy systems rely solely on voltage protection mechanisms due to cost constraints. When the battery voltage exceeds 55V (the nominal battery voltage is 48V), the controller cuts off the output to the motor. However, during long downhill runs, the vehicle's continuous potential energy is converted into electrical energy by the motor. Even if the controller cuts off the output to the motor, the continuous backflow current will still cause the controller to withstand excessive voltage, making it highly susceptible to damage due to overvoltage. This seriously affects the normal operation of the vehicle and may even lead to safety accidents. Industry reports indicate that lithium battery fires caused by lithium battery issues during downhill driving with a full charge account for a significant proportion of all new energy vehicle safety incidents. This not only causes enormous losses to consumers' lives and property but also negatively impacts the healthy development of the new energy vehicle industry and consumer trust. Summary of the Invention

[0003] In view of the above situation and to overcome the defects of the prior art, the present invention provides a method and system for protecting low-voltage new energy vehicle lithium batteries when fully charged on a downhill slope, which at least partially solves the problems mentioned in the background art.

[0004] The technical solution adopted in this invention is as follows: In a first aspect, the present invention provides a method for protecting a low-voltage new energy vehicle lithium battery from a downhill slope when fully charged, the method comprising: S1. Obtain the state of charge (SOC) of the lithium battery through the SOC detection unit integrated into the lithium battery current protection board. S2. Real-time vehicle speed and speed increase information are collected through the speed detection sensor of the state detection module; S3. Obtain whether the vehicle's driving slope is greater than 5% or less than 2% through the slope detection unit of the status detection module.

[0005] S4. The control module combines the battery state of charge, vehicle speed and speed increase information collected by the speed sensor, and slope information collected by the slope detection unit to determine whether the preset conditions are met: When the state of charge (SOC) of the lithium battery is ≥95% and the gradient is >5% or the vehicle speed exceeds the rated speed, a control command is triggered to turn off the energy recovery function and the hill descent control function, and to cut off the energy recovery circuit to prevent the backflow current from entering the lithium battery. S5. Continuously detect vehicle speed increase: When the vehicle speed exceeds the rated speed or the vehicle speed acceleration is greater than 2m / s², the motor MOSFET is turned on through the active speed limiting module to dissipate electrical energy, and an audible and visual alarm is triggered simultaneously, prompting the user to use mechanical braking. When SOC ≤ 90% or slope < 2%, the above-mentioned functions will be automatically deactivated and active protection operations will be lifted, restoring the vehicle to normal driving status.

[0006] As a preferred technical solution, the power dissipation in S5 satisfies: P_dissipate=K×(V_bat-48)×I_max, where K=0.7 is the safety factor, I_max=150A, and V_bat is the real-time voltage of the lithium battery.

[0007] As a preferred technical solution, the microcontroller in step S4 is the MCU XMC1302 model.

[0008] The XMC1302 MCU features a high-performance ARM Cortex-M0+ core, a multi-channel ADC, and rich communication interfaces. It can efficiently process SOC estimation, slope recognition, and vehicle speed monitoring data. Through precise PWM output, it can control energy recovery cutoff and MOSFET power consumption in real time, providing safe and reliable core computing and control support for the fully charged downhill protection system.

[0009] Secondly, the present invention provides a system for protecting low-voltage new energy vehicle lithium batteries during downhill driving when fully charged, the system comprising: The status detection module includes a SOC detection unit for detecting the SOC of the lithium battery, a slope detection unit for detecting the vehicle's driving gradient, and a speed detection sensor for detecting the vehicle speed and speed increase. The SOC detection unit is integrated into the lithium battery current protection board. The status detection module can output lithium battery SOC data, slope data, vehicle speed and speed increase data in real time. The control module uses an MCU XMC1302 as its core controller to receive detection data from the status detection module and output control commands according to preset logic. When the lithium battery SOC is detected to be ≥95%, and the slope is >5% or the vehicle speed exceeds the rated speed, the first control command is output. When the vehicle speed exceeds the rated speed or the vehicle acceleration is greater than 2 m / s², the second control command is output. When the lithium battery SOC is detected to be ≤90% or the slope is <2%, a reset command is output. The execution module includes: The energy recovery control unit is used to receive the first control command from the control module, turn off the energy recovery function and the steep slope descent function, and cut off the energy recovery circuit to prevent the backflow current from entering the lithium battery. The active speed limiting module is used to receive the second control command from the control module and execute the speed limiting operation; The MOS power dissipation circuit reuses the motor drive bridge arm and turns on the MOS transistor after receiving the second control command from the control module to dissipate excess power. The alarm module, including a buzzer and an alarm light, is used to receive the second control command from the control module to execute the audible and visual alarm operation and prompt the user to use the mechanical brake; at the same time, it receives the reset command from the control module to stop the audible and visual alarm.

[0010] In one specific implementation, the speed detection sensor reuses the speed detection circuit of the original controller, including a Hall sensor, a magnetic encoder, or a rotary encoder.

[0011] In one specific implementation, the MOS power consumption circuit reuses the motor-driven MOS transistor and adds an additional heat dissipation structure.

[0012] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: By using a collaborative judgment method of SOC≥95% and downhill conditions, combined with three-level active protection logic, energy recovery can be cut off in time and the power consumption of MOSFETs can be controlled to stabilize the protection board current within the 100A safety threshold and control the battery temperature at 65±3℃. This avoids the risk of protection board breakdown caused by excessive backflow current and thermal runaway caused by electrolyte decomposition, and significantly reduces the probability of lithium battery fire accidents. Through precise operating condition judgment and automatic recovery mechanism, the problem of overcharging at full charge is avoided from the source, which increases the cycle life of lithium battery by 2 times and effectively reduces capacity decay. By reusing the vehicle's original speed sensor, motor drive MOSFET, and other hardware, and making only minor modifications to the heat dissipation structure, and using the low-cost MCU XMC1302 for core control, the modification cost is significantly reduced. It is also particularly compatible with 48V low-voltage systems, meeting the actual needs of low-voltage new energy vehicles such as mountain logistics vehicles and sightseeing vehicles. It completely solves the industry pain point that traditional voltage protection alone is prone to failure under long downhill conditions, providing a strong guarantee for the safe operation of low-voltage new energy vehicles. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0014] Figure 1 This is a schematic diagram of a low-voltage new energy vehicle lithium battery downhill protection method in an embodiment of the present invention; Figure 2 This is a schematic diagram of the architecture of a low-voltage new energy vehicle lithium battery downhill protection system in an embodiment of the present invention. Detailed Implementation

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] Currently, most low-voltage new energy systems rely solely on voltage protection mechanisms due to cost constraints. When the battery voltage exceeds 55V (the nominal battery voltage is 48V), the controller cuts off the output to the motor. However, during long downhill runs, the vehicle's continuous potential energy is converted into electrical energy by the motor. Even if the controller cuts off the output to the motor, the continuous backflow current will still cause the controller to withstand excessive voltage, making it highly susceptible to damage due to overvoltage. This seriously affects the normal operation of the vehicle and may even lead to safety accidents.

[0019] Recognizing the above problems, this application proposes and discloses a method and system for protecting low-voltage new energy vehicle lithium batteries under full-charge downhill conditions. This method provides comprehensive protection for low-voltage new energy vehicle lithium batteries under full-charge downhill conditions, avoids the risk of protection board breakdown caused by excessive backflow current, reduces the risk of thermal runaway, and significantly improves the service life of lithium batteries.

[0020] See Figure 1 In a first aspect, this embodiment provides a method for protecting a low-voltage new energy vehicle lithium battery from a downhill slope when fully charged, the method comprising: S1. Obtain the state of charge (SOC) of the lithium battery through the SOC detection unit integrated into the lithium battery current protection board. S2. Real-time vehicle speed and speed increase information are collected through the speed detection sensor of the state detection module; S3. Obtain whether the vehicle's driving slope is greater than 5% or less than 2% through the slope detection unit of the status detection module.

[0021] S4. The control module combines the battery state of charge, vehicle speed and speed increase information collected by the speed sensor, and slope information collected by the slope detection unit to determine whether the preset conditions are met: When the state of charge (SOC) of the lithium battery is ≥95% and the gradient is >5% or the vehicle speed exceeds the rated speed, a control command is triggered to turn off the energy recovery function and the hill descent control function, and to cut off the energy recovery circuit to prevent the backflow current from entering the lithium battery. S5. Continuously detect vehicle speed increase: When the vehicle speed exceeds the rated speed or the vehicle speed acceleration is greater than 2m / s², the motor MOSFET is turned on through the active speed limiting module to dissipate electrical energy, and an audible and visual alarm is triggered simultaneously, prompting the user to use mechanical braking. When SOC ≤ 90% or slope < 2%, the above-mentioned functions will be automatically deactivated and active protection operations will be lifted, restoring the vehicle to normal driving status.

[0022] In this embodiment, the specific protection triggering algorithm is implemented as follows: void slope_protection(float soc, float slope, float speed_rate) { if (soc>= 0.95f && slope>0.05f) { disable_regen(); / / Disable energy recycling if (speed_rate>2.0f) { / / Vehicle speed increase > 2m / s² enable_mos_heating(); / / Intermittent conduction of the MOS transistor consumes energy. activate_alarm(); / / Sound and light alarm } } } For example, in the operation procedure of a 48V system: When the vehicle enters a long downhill slope, with a SOC of 95% and a gradient of 5%, and approaches the rated speed, the controller immediately: - Disconnect the energy recovery circuit to prevent the voltage from rising above 58V. -Disable slope descent control When the vehicle speed accelerates from 40km / h to 60km / h, exceeding the rated speed by more than 25%: - The three-phase MOSFET is turned on, causing the motor to short-circuit intermittently, consuming 1kw-3kW of the power generated by the motor; - Triggers a rapid buzzer sound and a flashing red light.

[0023] The dashboard displays a warning: "Downhill protection in progress, please use the brakes!" The protection will automatically disengage when the vehicle reaches the bottom of the slope (SOC=92%).

[0024] Comparison based on actual measurement data: When a vehicle is fully charged and going downhill (SOC=90%), the traditional solution will break down the lithium battery overcurrent protection board when the backflow voltage is >58V; the present invention, however, keeps the voltage stable at ≤54V by turning off energy recovery.

[0025] When the vehicle continues to descend a slope for 5 kilometers, the lithium battery temperature rises to 70°C in the traditional solution, causing thermal runaway. The present invention uses an active speed limiting module to conduct the motor MOSFET to dissipate power, controlling the lithium battery temperature to ≤50°C and the energy dissipation rate to >85%.

[0026] When a vehicle is going downhill at excessive speed and the acceleration is greater than 3m / s², the traditional mechanical braking system is prone to causing accidents. This invention uses audible and visual alarms and active speed limiting response of <1s. The first-level warning system is a buzzer alarm in the driver's cab with a volume greater than 80dB, and the second-level warning system is a flashing red light on the outside of the vehicle with a visibility distance of >50m.

[0027] This solution employs a three-tiered active protection mechanism and collaborative judgment logic to provide comprehensive protection for low-voltage new energy vehicle lithium batteries under full-charge downhill conditions. In practical applications, the lithium battery protection board current can be stably controlled within the 100A safety threshold, effectively avoiding the risk of protection board breakdown due to excessive backflow current. Simultaneously, through active temperature control methods such as MOSFET conduction energy dissipation, the battery temperature can be stably maintained at 65±3℃, far below the 80℃ critical value that triggers electrolyte decomposition, fundamentally reducing the risk of thermal runaway. Furthermore, this solution cuts off continuous backflow overcharging under full-charge conditions at the source, completely avoiding the lithium battery capacity decay problem caused by overcharging. Actual verification shows that the lithium battery cycle life can be increased by 2 times, ensuring vehicle operation safety and significantly extending battery life, thus solving the long-standing industry pain point of safety issues related to full-charge downhill overcharging.

[0028] In one specific implementation, the power dissipation in S5 satisfies: P_dissipate=K×(V_bat-48)×I_max, where K=0.7 is the safety factor, I_max=150A, and V_bat is the real-time voltage of the lithium battery.

[0029] 48V is the nominal voltage of the battery, and V_bat represents the real-time voltage of the lithium battery. The difference between the two (V_bat - 48) directly reflects the overvoltage amplitude caused by the backflush current: the larger the difference, the more serious the voltage over-limit caused by backflush, and the more excess electrical energy needs to be dissipated.

[0030] I_max=150A is the maximum allowable current for the MOS heat dissipation module. This value is higher than the industry-standard 100A recoil current, ensuring effective current shunt even under extreme recoil conditions. K=0.7 serves as a safety factor to reduce the actual load pressure on the MOS transistor, preventing it from overheating and being damaged due to prolonged high-power operation.

[0031] When the microcontroller detects that the lithium battery's SOC is ≥ 95% and the speed sensor confirms a downhill condition, it can calculate the required power dissipation based on the real-time collected V_bat, and then adjust the conduction level of the MOSFET to precisely match the power consumption with the risk of overvoltage. This avoids the risk of overcharging due to insufficient power consumption, and also prevents energy waste and device damage caused by excessive power consumption, ultimately realizing the module function of "safely dissipating excess power," forming a collaborative protection system with the energy recovery control unit and the active speed limiting module.

[0032] See Figure 2 Secondly, this embodiment provides a low-voltage new energy vehicle lithium battery full-charge downhill protection system, the system comprising: The status detection module includes a SOC detection unit for detecting the SOC of the lithium battery, a slope detection unit for detecting the vehicle's driving gradient, and a speed detection sensor for detecting the vehicle speed and speed increase. The SOC detection unit is integrated into the lithium battery current protection board. The status detection module can output lithium battery SOC data, slope data, vehicle speed and speed increase data in real time. The control module uses an MCU XMC1302 as its core controller to receive detection data from the status detection module and output control commands according to preset logic. When the lithium battery SOC is detected to be ≥95%, and the slope is >5% or the vehicle speed exceeds the rated speed, the first control command is output. When the vehicle speed exceeds the rated speed or the vehicle acceleration is greater than 2 m / s², the second control command is output. When the lithium battery SOC is detected to be ≤90% or the slope is <2%, a reset command is output. The execution module includes: The energy recovery control unit is used to receive the first control command from the control module, turn off the energy recovery function and the steep slope descent function, and cut off the energy recovery circuit to prevent the backflow current from entering the lithium battery. The active speed limiting module is used to receive the second control command from the control module and execute the speed limiting operation; The MOS power dissipation circuit reuses the motor drive bridge arm and turns on the MOS transistor after receiving the second control command from the control module to dissipate excess power. The alarm module, including a buzzer and an alarm light, is used to receive the second control command from the control module to execute the audible and visual alarm operation and prompt the user to use the mechanical brake; at the same time, it receives the reset command from the control module to stop the audible and visual alarm.

[0033] In the low-voltage new energy vehicle lithium battery full-charge downhill protection system of the present invention, each core module forms a complete control link through orderly data transmission and command interaction. The specific architecture process can be further explained as follows: During the data acquisition phase, the SOC acquisition unit collects the voltage and current data of the lithium battery pack in real time, calculates the SOC value using the ampere-hour integration method combined with the open-circuit voltage correction algorithm, and the sampling frequency is ≥10Hz; the slope detection unit uses a MEMS triaxial accelerometer, combines the vehicle dynamics model to eliminate driving acceleration interference, and outputs the true slope value; the speed detection sensor reuses the motor Hall sensor, performs frequency measurement through the CAPCOM module of the MCU XMC1302, converts it into a vehicle speed value, and calculates the acceleration through a differential algorithm.

[0034] During the control decision and execution response phase, the MCU XMC1302, acting as the core controller, receives detection data from the status detection module and outputs control commands according to preset logic. When the lithium battery's state of charge (SOC) is ≥95% and the gradient is >5% or the vehicle speed exceeds the rated speed, the energy recovery function and hill descent control function are turned off, and the energy recovery circuit is disconnected to prevent backflow current from entering the lithium battery. When the vehicle speed exceeds the rated speed or the vehicle acceleration is >2m / s², the motor MOSFET is turned on through the active speed limiting module to dissipate electrical energy, and an audible and visual alarm is triggered simultaneously, prompting the user to use mechanical braking. When the SOC is ≤90% or the gradient is <2%, the above functions are automatically deactivated and the active protection operation is lifted, restoring the vehicle to normal driving status.

[0035] During the alarm feedback phase, the buzzer uses an LM386 power amplifier with an output power of 1W, an alarm frequency of 2.5kHz, and a sound pressure level of ≥85dB (A); the alarm light flashes at a frequency of 3Hz and has a visibility distance of over 50 meters.

[0036] In one specific implementation, the speed detection sensor reuses the speed detection circuit of the original controller, including a Hall sensor, a magnetic encoder, or a rotary encoder.

[0037] In one specific implementation, the MOS power consumption circuit reuses the motor-driven MOS transistor and adds an additional heat dissipation structure.

[0038] This system reuses the vehicle's original hardware and combines it with a three-level active protection mechanism to control the lithium battery protection board current within a safe threshold and stabilize the battery temperature to avoid thermal runaway under full-charge downhill conditions. At the same time, it avoids capacity decay caused by overcharging and extends battery cycle life, effectively ensuring the safe operation of low-voltage new energy vehicles while controlling costs.

[0039] It should be noted that, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0040] Although embodiments have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit, the scope of which is defined by the appended claims and their equivalents.

[0041] The embodiments have been described above, and such description is not restrictive. The figures shown are only one embodiment, and the actual structure is not limited to this. In short, if a person skilled in the art is inspired by this description and designs a similar structure and embodiment without departing from the inventive spirit, such design should fall within the scope of protection.

Claims

1. A method for protecting a low-voltage new energy vehicle lithium battery during downhill driving when fully charged, characterized in that, The method includes: S1. Obtain the state of charge (SOC) of the lithium battery through the SOC detection unit integrated into the lithium battery current protection board. S2. Real-time vehicle speed and speed increase information are collected through the speed detection sensor of the state detection module; S3. Obtain whether the vehicle's driving slope is greater than 5% or less than 2% through the slope detection unit of the status detection module. S4. The control module combines the battery state of charge, the vehicle speed and speed increase information collected by the speed sensor, and the slope information collected by the slope detection unit to determine whether the preset conditions are met: When the state of charge (SOC) of the lithium battery is ≥95% and the gradient is >5% or the vehicle speed exceeds the rated speed, a control command is triggered to turn off the energy recovery function and the hill descent control function, and to cut off the energy recovery circuit to prevent the backflow current from entering the lithium battery. S5, Continuously detect vehicle speed increase: When the vehicle speed exceeds the rated speed or the vehicle speed acceleration is greater than 2m / s², the motor MOSFET is turned on through the active speed limiting module to dissipate electrical energy, and an audible and visual alarm is triggered simultaneously, prompting the user to use mechanical braking. When SOC ≤ 90% or slope < 2%, the above-mentioned functions will be automatically deactivated and active protection operations will be lifted, restoring the vehicle to normal driving status.

2. The method for protecting low-voltage new energy vehicle lithium batteries from a fully charged downhill slope according to claim 1, characterized in that, The power dissipation in S5 satisfies: P_dissipate=K×(V_bat-48)×I_max, where K=0.7 is the safety factor, I_max=150A, and V_bat is the real-time voltage of the lithium battery.

3. The method for protecting low-voltage new energy vehicle lithium batteries from a downhill slope when fully charged, as described in claim 1, is characterized in that... The microcontroller in step S4 is the MCU XMC1302 model.

4. A low-voltage new energy vehicle lithium battery full-charge downhill protection system, characterized in that, include: The status detection module includes a SOC detection unit for detecting the SOC of the lithium battery, a slope detection unit for detecting the vehicle's driving gradient, and a speed detection sensor for detecting the vehicle speed and speed increase. The SOC detection unit is integrated into the lithium battery current protection board. The status detection module can output lithium battery SOC data, slope data, vehicle speed and speed increase data in real time. The control module uses an MCU XMC1302 as its core controller to receive detection data from the status detection module and output control commands according to preset logic. When the lithium battery SOC is detected to be ≥95%, and the slope is >5% or the vehicle speed exceeds the rated speed, the first control command is output. When the vehicle speed exceeds the rated speed or the vehicle acceleration is greater than 2 m / s², the second control command is output. When the lithium battery SOC is detected to be ≤90% or the slope is <2%, a reset command is output. The execution module includes: The energy recovery control unit is used to receive the first control command from the control module, turn off the energy recovery function and the steep slope descent function, and cut off the energy recovery circuit to prevent the backflow current from entering the lithium battery. The active speed limiting module is used to receive the second control command from the control module and execute the speed limiting operation; The MOS power dissipation circuit reuses the motor drive bridge arm and turns on the MOS transistor after receiving the second control command from the control module to dissipate excess power. The alarm module, including a buzzer and an alarm light, is used to receive the second control command from the control module to execute the audible and visual alarm operation and prompt the user to use the mechanical brake; at the same time, it receives the reset command from the control module to stop the audible and visual alarm.

5. The low-voltage new energy vehicle lithium battery full-charge downhill protection system according to claim 4, characterized in that, The speed detection sensor reuses the speed detection circuit of the original controller, including a Hall sensor, a magnetic encoder, or a rotary encoder.

6. The low-voltage new energy vehicle lithium battery full-charge downhill protection system according to claim 4, characterized in that, The MOS power consumption circuit reuses the motor-driven MOS transistor and adds an additional heat dissipation structure.

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