Method and system for avoiding braking heat fade during heavy-load downhill of pure electric vehicle

Abstract

The invention relates to a method and system for avoiding braking heat fade of a pure electric vehicle during heavy-load downhill, and belongs to the technical field of electric vehicles. According to the driving route input by the driver, the unit distance power consumption of the vehicle on the corresponding driving route and non-downhill road sections in the historical data and the recharging electric quantity returned and recovered by the vehicle on the downhill road sections through braking, the vehicle can reach the end point of the driving route. And reversely calculating the SOC of the power battery of the driving route starting point which ensures that the SOC of the power battery at any position of the downhill road section does not exceed a set upper limit from the end point of the driving route to the driving route starting point, and outputting the recommended SOC of the power battery as the driving route starting point. And the situation that the vehicle has no braking feedback electric quantity in a high SOC section is avoided, so that the problems of braking heat fade and braking failure caused by long-time mechanical braking are thoroughly solved, the driving safety of the vehicle is guaranteed, and the service life of the device is prolonged.

Description

Technical Field

[0001] The invention relates to a method and a system for preventing thermal decay in braking of a pure electric vehicle when going downhill with heavy load, and belongs to the technical field of electric vehicles. Background Art

[0002] As pure electric technology matures, the standards for clean transportation in the electricity, coal, steel, chemical, logistics, mining and other industries are getting higher and higher. Pure electric commercial vehicles account for a larger share of the industry, and the scene where heavy-loaded vehicles need to brake for a long time when going downhill is becoming more and more common. The braking of pure electric vehicles mainly relies on electric retarding and mechanical braking. When the SOC is at a high state, the electric retarding force is insufficient and mechanical braking needs to intervene; when mechanical braking is intervened for a long time, it is very easy to cause brake thermal decay and brake failure in a short period of time, which in turn causes safety accidents.

[0003] In actual use conditions at this stage, there are more and more scenarios where mechanical braking needs to be intervened for a long time when the SOC is at a high state under long downhill conditions such as mountainous areas, mining areas, and hills. The driver needs to spend a lot of energy to calculate the amount of electricity required for charging to avoid the battery being in a high SOC state. The braking mode of existing pure electric vehicles is to give priority to electric retarding braking, and mechanical braking intervenes when the electric retarding braking force is insufficient. In the first stage, electric retarding braking, the battery management system sends a fixed allowable feedback current value (electric retarding capability) according to the battery MAP. When the SOC is at a high state, the electric retarding braking is very weak or almost non-existent, and the mechanical brake intervenes at this time. After the mechanical brake intervenes, if the vehicle is in a heavy-loaded downhill state, the mechanical brake thermal decay state will be reached in 1~2 minutes, resulting in brake failure. To solve the problem of mechanical brake thermal decay state, the common solutions in the industry are as follows: 1. Before the vehicle is driven, the driver is reminded that the SOC should be at the low end before going downhill. However, during driving, the driver's control of the vehicle's power battery SOC based on the actual situation is often not effective; 2. Adding additional devices such as eddy current can only increase the braking force to a limited extent and the cost is high; 3. Adding sprinklers to spray water will cause the road surface to become slippery and icy, posing serious driving hazards.

[0004] Existing new energy vehicle technology mainly relies on careful manual control to avoid the occurrence of high SOC state during long downhill slopes, or adds devices such as eddy currents, which leads to increased vehicle costs, causing more inconvenience to end users, and cannot completely solve the problem. Summary of the invention

[0005] The purpose of the present invention is to provide a method and system for preventing brake thermal decay in a pure electric vehicle when going downhill with a heavy load. The present invention provides a solution for calculating the SOC of the power battery based on big data for the driver's reference during vehicle driving, so as to avoid the problem of no brake feedback power in a high SOC section in a heavy-loaded long downhill environment, and then the problem of mechanical brake thermal decay and brake failure.

[0006] To achieve the above object, the solution of the present invention includes: A method for avoiding brake thermal decay when a pure electric vehicle is traveling downhill with a heavy load of the present invention is based on a driving route input by a driver, based on the power consumption per unit distance of the vehicle on a non-downhill section of the corresponding driving route in historical data, and the power replenishment amount recovered by the vehicle through braking feedback on the downhill section, and on the premise that the vehicle can reach the end point of the driving route, a reverse calculation is performed from the end point of the driving route toward the starting point of the driving route to ensure that the SOC of the power battery at any position on the downhill section does not exceed the SOC of the power battery at the starting point of the driving route with a set upper limit, and a recommended power battery SOC is output as the starting point of the driving route.

[0007] Furthermore, based on the preset power battery power limit SOC, according to the vehicle's power consumption per unit distance on non-downhill sections on the corresponding driving route in historical data, and the power replenishment recovered by the vehicle through braking feedback on the downhill section, it is ensured that the power battery has at least the power battery power limit SOC when the vehicle reaches the end of the driving route, and the power battery has at least the discharge cut-off SOC at each charging position in the driving route. The required power battery SOC required for the vehicle at each charging position in the driving route is calculated reversely from the end point of the driving route to the starting point, and the required power battery SOC is output as the required charging cut-off SOC for the corresponding charging position on the driving route.

[0008] Furthermore, the starting point, the end point and the power battery power limit SOC are input through the vehicle's human-computer interaction interface and sent to the cloud server through the on-board communication device. The cloud server generates the driving route according to the starting point and the end point, calculates the recommended power battery SOC, the power battery feedback charging cut-off SOC corresponding to each charging position, and pushes them to the driver.

[0009] Furthermore, the cloud server also sends the recommended power battery SOC and the power battery feedback charging cut-off SOC corresponding to each charging position to the vehicle; before the vehicle departs and is in the charging state, the vehicle sets the power battery charging cut-off SOC to the recommended power battery SOC; when the vehicle is charging at the charging position on the driving route, the vehicle sets the power battery charging cut-off SOC to the corresponding required charging cut-off SOC.

[0010] The beneficial effects of the present invention are as follows: a method for preventing brake thermal decay in a heavy-loaded downhill pure electric vehicle of the present invention calculates the power battery SOC at the starting point of the driving route and the required power battery SOC at each charging position in the driving route according to the driving route input by the driver, the vehicle unit distance power consumption in the non-downhill section of the corresponding driving route in historical data, and the feedback power replenishment power of the vehicle in the downhill section. It avoids the situation where the vehicle has no brake feedback power in the high SOC section, thereby completely solving the problem of brake thermal decay and brake failure caused by long-term mechanical braking, ensuring vehicle driving safety and increasing the service life of the device.

[0011] The present invention also provides a system for preventing thermal decay of brakes when a pure electric vehicle is traveling downhill with a heavy load, comprising a processor, wherein the processor is used to execute a computer program to realize, based on a driving route input by a driver, the power consumption per unit distance of the vehicle on a non-downhill section on the corresponding driving route in historical data, and the power replenishment recovered by the vehicle through braking feedback on the downhill section, reversely calculating from the end point of the driving route toward the starting point of the driving route to ensure that the SOC of the power battery at any position on the downhill section does not exceed the SOC of the power battery at the starting point of the driving route with a set upper limit, on the premise that the vehicle can reach the end point of the driving route, and outputting a recommended power battery SOC as the starting point of the driving route.

[0012] Furthermore, based on the preset power battery power limit SOC, according to the vehicle's power consumption per unit distance on non-downhill sections on the corresponding driving route in historical data, and the power replenishment recovered by the vehicle through braking feedback on the downhill section, it is ensured that the power battery has at least the power battery power limit SOC when the vehicle reaches the end of the driving route, and the power battery has at least the discharge cut-off SOC at each charging position in the driving route. The required power battery SOC required for the vehicle at each charging position in the driving route is calculated reversely from the end point of the driving route to the starting point, and the required power battery SOC is output as the required charging cut-off SOC for the corresponding charging position on the driving route.

[0013] Furthermore, the starting point, the end point and the power battery power limit SOC are input through the vehicle's human-computer interaction interface and sent to the cloud server through the on-board communication device. The cloud server generates the driving route according to the starting point and the end point, calculates the recommended power battery SOC, the power battery feedback charging cut-off SOC corresponding to each charging position, and pushes them to the driver.

[0014] Furthermore, the cloud server also sends the recommended power battery SOC and the power battery feedback charging cut-off SOC corresponding to each charging position to the vehicle; before the vehicle departs and is in the charging state, the vehicle sets the power battery charging cut-off SOC to the recommended power battery SOC; when the vehicle is charging at the charging position on the driving route, the vehicle sets the power battery charging cut-off SOC to the corresponding required charging cut-off SOC.

[0015] The system for avoiding brake thermal decay when a pure electric vehicle is heavily loaded downhill involves the pure electric vehicle intelligent network connection, electronic control system, and power battery management system, and is applied to pure electric, hybrid and other models equipped with power batteries. Through the management of the whole vehicle and the power battery system, the vehicle operation route is adaptively identified, and the charging cut-off condition is intelligently identified. The present invention closely combines the intelligent network connection, the whole vehicle control system, the braking system, and the power supply system through an intelligent management and control strategy, and automatically estimates the charging charge state according to the actual use conditions of the pure electric vehicle, thereby achieving beneficial effects consistent with the method for avoiding brake thermal decay when a pure electric vehicle is heavily loaded downhill. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of a method for preventing thermal decay of braking when a pure electric vehicle is heavily loaded downhill according to the present invention; Figure 2 It is a driving route diagram; Figure 3 It is a schematic diagram of the driving route including charging stations. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail in a clear and complete manner in conjunction with the accompanying drawings and embodiments.

[0018] The concept of the present invention is as follows: a method and system for preventing brake thermal decay when a pure electric vehicle is heavily loaded and driving downhill of the present invention, based on the driving route input by the driver, the power consumption per unit distance of the vehicle on the corresponding driving route in the historical data, and the power replenishment power recovered by the vehicle through brake feedback on the downhill section, on the premise that the vehicle can reach the end of the driving route, reverse calculation is performed from the end of the driving route to the starting point of the driving route to ensure that the power battery SOC at any position of the downhill section does not exceed the power battery SOC at the starting point of the driving route with a set upper limit, and the recommended power battery SOC is output as the starting point of the driving route. The situation where the vehicle has no brake feedback power in the high SOC section is avoided, thereby completely solving the problem of brake thermal decay and brake failure caused by long-term mechanical braking, ensuring vehicle driving safety and increasing the service life of the device.

[0019] Method Example 1: This embodiment provides a method for preventing thermal decay of brakes when a pure electric vehicle is heavily loaded downhill. It is applicable to large-scale commercial pure electric vehicles with cargo loads, such as mine cars or coal cars. Each driving route is under multiple downhill conditions. There are frequent high SOC sections, which result in no brake feedback power for the vehicle, and thus lead to the dangerous problem of thermal decay of mechanical brakes and brake failure. Figure 1 As shown, the method uses big data to calculate the vehicle battery operation model for the driving route input by the driver. The vehicle battery operation model calculates the power consumption per unit distance of the vehicle in the non-downhill section on the corresponding driving route in the historical data, and the power replenishment power recovered by the vehicle through braking feedback on the downhill section. On the premise that the vehicle can reach the end of the driving route, the reverse calculation is performed from the end of the driving route to the starting point of the driving route to ensure that the power battery SOC at any position on the downhill section does not exceed the power battery SOC of the starting point of the driving route with a set upper limit, and the recommended power battery SOC is output as the starting point of the driving route.

[0020] by Figure 2 Taking the figure as an example, the specific calculation method of the vehicle battery operation model is as follows: The driver inputs the starting point P1 and the end point P6, and the driving route is "P1-P2-P3-P4-P5-P6", among which "P4-P5" is a downhill section condition, and "P1-P2", "P2-P3", "P3-P4" and "P5-P6" are non-downhill section conditions. Ensure that when the vehicle reaches the end point P6, the vehicle's power battery SOC is not lower than the power battery's discharge cut-off SOC (to protect the battery's health and prevent over-discharge). Generally, the discharge cut-off SOC is 10. Take the vehicle's discharge cut-off SOC of 10 at the end point P6 as an example to calculate the vehicle battery operation model. Big data is used to calculate the vehicle's power consumption per unit distance on the non-downhill section of the "P1-P2-P3-P4-P5-P6" driving route in historical data, as well as the feedback power of the vehicle on the downhill section. The total power battery SOC consumed in the "P5-P6" section is 35. At point P5, in order to ensure that the vehicle can complete the route, the vehicle's power battery SOC must be greater than 45; the feedback power of the vehicle on the downhill section of "P4-P5" is greater than 45. If the power battery SOC is 25, then at point P4, the vehicle's power battery SOC must be greater than 20 and less than the difference between the power battery feedback charging cut-off SOC and the feedback charging power battery SOC of the vehicle on the "P4-P5" downhill section. Taking the power battery feedback charging cut-off SOC as 80 as an example, at point P4, the vehicle's power battery SOC must be greater than 20 and less than 55; the power battery SOC consumed in the "P1-P4" section is 20, then the power battery SOC calculation range of the vehicle at the starting point is 40~75, and the upper limit of the power battery does not exceed the feedback charging cut-off SOC. It is calculated through the vehicle battery operation model that the recommended power battery SOC at the starting point of the "P1-P2-P3-P4-P5-P6" driving route is any value in the range of 40~75.

[0021] Furthermore, before the vehicle sets off, the driver inputs the starting point and the end point through the APP software of the vehicle's human-computer interaction interface, and sends it to the cloud server through the on-board communication device. The cloud server generates the driving route and calculates the recommended power battery SOC at the starting point of the driving route.

[0022] The APP software with the human-computer interaction interface includes functions such as China real-time map (which can be updated in real time with commercial maps), vehicle search, vehicle query, vehicle positioning, customized operation routes or manual definition of operation scope, cloud server suggestion, application formulation and cancellation, etc.

[0023] The cloud server is equipped with data storage and processor, and can establish corresponding vehicle battery operation models based on the actual operating conditions of different customers, and push the recommended power battery SOC at the starting point of the driving route to the APP and BMS.

[0024] The BMS, when receiving the recommended power battery SOC at the starting point of the vehicle's driving route, sets the charging end SOC of the power battery to the recommended power battery SOC before the vehicle departs and is in a charging state, to ensure that the vehicle is always in the optimal stage of electric deceleration during driving.

[0025] At the same time, communication failures are the most common failures of heavy vehicles. BMS includes a communication failure processing mode. After the customer enters the recommended operation mode through the APP, when the vehicle has a communication failure (that is, when the vehicle fails to communicate with the cloud server), the vehicle can continue to operate according to the mode pushed by the cloud server before departure, without limiting the power of the vehicle. The charge and discharge of the battery in the vehicle's historical route has been fully simulated in the cloud server. When a communication failure occurs during operation, the BMS can allow the power system to charge and discharge normally according to the model record, reducing the vehicle breakdown failure rate.

[0026] When a communication failure occurs inside the battery, the cloud server calculates the safe operation time of the vehicle based on the battery status before the failure through the vehicle battery operation model, and provides solutions for the driver, including vehicle operation time reminder and optimal parking location planning.

[0027] Method Example 2: This embodiment is based on the method embodiment 1, taking into account the situation that the driving route input by the driver is long, the vehicle power battery SOC is not enough to ensure that the vehicle completes the driving, and charging is required during the driving route. Therefore, based on the preset power battery power limit SOC, according to the vehicle unit distance power consumption on the non-downhill section of the corresponding driving route in the historical data, and the supplementary power recovered by the vehicle through braking feedback on the downhill section, it is ensured that the power battery has at least the power battery power limit SOC when the vehicle reaches the end of the driving route, and the power battery has at least the discharge cut-off SOC at each charging position in the driving route. The required power battery SOC required by the vehicle at each charging position in the driving route is calculated from the end of the driving route to the starting point, and the required power battery SOC is output as the required charging cut-off SOC for the corresponding charging position on the driving route.

[0028] by Figure 3 Taking the figure as an example, the specific calculation method of the vehicle battery operation model is as follows: The driver inputs the starting point P1, the end point P6 and the power battery power limit SOC, and the driving route is "P1-P2-P3-P4-P5-P6-P7-P8", where P5 is the second charging position in the driving route and P3 is the first charging position in the driving route. It is ensured that when the vehicle reaches the end point P8, the vehicle's power battery SOC is not lower than the power battery power limit SOC, that is, the power battery power limit SOC required by the driver when the vehicle reaches the end point. The power battery power limit SOC is generally set to 10. Taking the power battery power limit SOC of 10 when the vehicle is at the end point P8 as an example, the vehicle battery operation model is calculated, and big data is used according to the vehicle unit distance power consumption on the non-downhill section of the "P5-P6-P7-P8" driving route in the historical data, and the feedback power of the vehicle on the downhill section. The total power battery SOC consumed in the "P7-P8" section is 20. At point P7, in order to ensure that the vehicle can complete the route, the vehicle's power battery SOC must be greater than 30; the feedback power battery SOC of the vehicle on the "P6-P7" downhill section is 5. At point P6, the vehicle's power battery SOC must be greater than 25 and less than the difference between the power battery feedback charging cut-off SOC and the feedback power battery SOC of the vehicle on the "P6-P7" downhill section. Taking the power battery feedback charging cut-off SOC as 80 as an example, at point P6, the vehicle's power battery SOC needs to be greater than 25 and less than 75; the power battery SOC consumed in the "P5-P6" section is 10, and the power battery SOC calculation range of the vehicle at the second charging position P5 is 35~80, and the required charging cut-off SOC at the second charging position P5 is any value within the range of 35~80. The same calculation method is used. When the vehicle reaches the second charging position P5, it is ensured that the vehicle's power battery SOC is not lower than the power battery's discharge cut-off SOC. The discharge cut-off SOC is generally set to 10, that is, the power battery SOC is not lower than 10. The vehicle battery operation model is calculated by using big data based on the vehicle's unit distance power consumption on the non-downhill section of the "P3-P5" driving route in historical data, as well as the feedback power calculation of the vehicle on the downhill section. The feedback power battery SOC of the vehicle on the "P4-P5" downhill section is 10. At point P4, the vehicle's power battery SOC must be greater than 10 and less than 70 (the power battery is not lower than the power battery power limit SOC during the driving route); the power battery SOC consumed on the "P3-P4" section is 25. The calculation range of the vehicle's power battery SOC at the first charging position P3 is between 35 and 80, and the required charging cut-off SOC at the first charging position P3 is any value within the range of 35 to 80.The same calculation method is used. When the vehicle reaches the first charging position P3, it is ensured that the vehicle's power battery SOC is not lower than the power battery's discharge cut-off SOC, that is, the power battery SOC is not lower than 10. The vehicle battery operation model is calculated by using big data based on the vehicle's unit distance power consumption on the non-downhill section of the "P1-P3" driving route in historical data, as well as the feedback power calculation of the vehicle on the downhill section. The feedback power battery SOC of the vehicle on the "P2-P3" downhill section is 20. At point P2, the vehicle's power battery SOC must be greater than 10 and less than 60. The power battery SOC consumed on the "P1-P2" section is 10. The power battery SOC calculation range of the vehicle at the starting point is 20~70, and the recommended power battery SOC at the starting point is any value within the range of 20~70.

[0029] Furthermore, the driver sets the starting point, end point, power battery power limit SOC and charging pile on the APP. According to the driver's designated charging pile, the charging pile set by the driver is pushed first during route planning to improve the driver's experience. The vehicle battery operation model is established based on the vehicle working condition, and the uphill and downhill working conditions are adaptively identified. Through the vehicle power consumption, mileage, system MAP, and charging pile layout, the driver is provided with the recommended power battery SOC at the starting point of the vehicle's driving route and the required charging end SOC of the corresponding charging location on the driving route.

[0030] If the location and number of charging piles along the way in the vehicle charging plan can guarantee the entire driving route of the vehicle, then when the driver charges at the charging location along the way and the battery SOC reaches the required charging end SOC, the vehicle will actively stop charging to ensure that when the vehicle is heavily loaded downhill, the battery SOC is always in the optimal stage of electric deceleration, avoiding the weakening of electric deceleration ability. This embodiment automatically adjusts and controls the charging strategy so that when the vehicle is often downhill, it is always in the maximum working efficiency range of electric deceleration (that is, the battery SOC does not exceed the battery SOC threshold for mechanical braking intervention), avoiding long-term mechanical braking on downhill sections, resulting in brake thermal decay and failure of the brake effect. If the location and number of charging piles along the way in the vehicle charging plan cannot guarantee the entire driving route of the vehicle, the cloud server will add charging piles suitable for the charging location according to the route planning to ensure the normal driving of the vehicle.

[0031] The mobile phone APP software includes functions such as China real-time map (which can be updated in real time with commercial maps), vehicle search, vehicle query, vehicle positioning, customized operation route or manual operation range, cloud server suggestion application and cancellation.

[0032] The cloud server is equipped with data storage and processor, and can establish corresponding vehicle battery operation models based on the actual operating conditions of different customers, and push the recommended power battery SOC at the starting point of the vehicle's driving route and the required charging end SOC of the corresponding charging location on the driving route to the APP and BMS.

[0033] The BMS, when receiving the recommended power battery SOC at the starting point of the vehicle's driving route and the required charging end SOC at the corresponding charging position on the driving route, sets the power battery's charging end SOC to the recommended power battery SOC before the vehicle departs and is in the charging state; when the vehicle is charging at the charging position on the driving route, sets the power battery's charging end SOC to the corresponding required charging end SOC, to ensure that the vehicle is always in the optimal stage of electric deceleration during driving.

[0034] At the same time, communication failures are the most common failures of heavy vehicles. BMS includes a communication failure processing mode. After the customer enters the recommended operation mode through the APP, when the vehicle has a communication failure (that is, when the vehicle fails to communicate with the cloud server), the vehicle can continue to operate according to the mode pushed by the cloud server before departure, without limiting the power of the vehicle. The charge and discharge of the battery in the vehicle's historical route has been fully simulated in the cloud server. When a communication failure occurs during operation, the BMS can allow the power system to charge and discharge normally according to the model record, reducing the vehicle breakdown failure rate.

[0035] When a communication failure occurs inside the battery, the cloud server calculates the safe operation time of the vehicle based on the battery status before the failure through the vehicle battery operation model, and provides solutions for the driver, including vehicle operation time reminder and optimal parking location planning.

[0036] System implementation for preventing thermal decay of brakes when a pure electric vehicle is heavily loaded downhill: This embodiment provides a system for preventing brake thermal decay when a pure electric vehicle is heavily loaded downhill. Through an intelligent management and control strategy, the intelligent network connection, vehicle control system, brake system, and power system are closely integrated, and the charging state is automatically estimated according to the actual use conditions of the pure electric vehicle. It involves the intelligent network connection, electric control system, and power battery management system of pure electric vehicles, and is applied to pure electric, hybrid and other models equipped with power batteries. Through the management of the whole vehicle and power battery system, the vehicle operation line is adaptively identified, and the charging cut-off condition is intelligently identified to avoid the situation where the vehicle has no brake feedback power in the high SOC section, thereby completely solving the problem of brake thermal decay and brake failure.

[0037] Since the specific implementation process and principle of the system for preventing thermal decay in braking of a pure electric vehicle with heavy load when going downhill in this embodiment have been described in detail in method embodiment 1 and method embodiment 2, they will not be elaborated here.

Claims

1. A method for preventing thermal decay of brakes when a pure electric vehicle is heavily loaded downhill, characterized in that: According to the driving route input by the driver, based on the vehicle's power consumption per unit distance on non-downhill sections on the corresponding driving route in historical data, and the power recovered by the vehicle through braking feedback on the downhill section, on the premise that the vehicle can reach the end point of the driving route, a reverse calculation is made from the end point of the driving route to the starting point of the driving route to ensure that the power battery SOC at any position on the downhill section does not exceed the power battery SOC at the starting point of the driving route with a set upper limit, and the recommended power battery SOC is output as the starting point of the driving route.

2. The method for avoiding thermal decay of braking when a pure electric vehicle is heavily loaded downhill according to claim 1, characterized in that: Also based on the preset power battery power limit SOC, according to the vehicle's power consumption per unit distance on non-downhill sections on the corresponding driving route in historical data, and the power recovered by the vehicle through braking feedback on the downhill section, on the premise that the power battery of the vehicle has at least the power battery power limit SOC when it reaches the end of the driving route, and the power battery has at least the discharge cut-off SOC at each charging position in the driving route, the required power battery SOC required for the vehicle at each charging position in the driving route is calculated reversely from the end point of the driving route to the starting point, and the required power battery SOC is output as the required charging cut-off SOC for the corresponding charging position on the driving route.

3. The method for avoiding brake thermal decay when a pure electric vehicle is heavily loaded downhill according to claim 2, characterized in that: The starting point, the end point and the power battery power limit SOC are input through the vehicle's human-computer interaction interface and sent to the cloud server through the on-board communication device. The cloud server generates the driving route according to the starting point and the end point, calculates the recommended power battery SOC, the power battery feedback charging cut-off SOC corresponding to each charging position, and pushes them to the driver.

4. The method for avoiding brake thermal decay when a pure electric vehicle is heavily loaded downhill according to claim 3, characterized in that: The cloud server also sends the recommended power battery SOC and the power battery feedback charging cut-off SOC corresponding to each charging position to the vehicle; before the vehicle departs and is in the charging state, the vehicle sets the power battery charging cut-off SOC to the recommended power battery SOC; when the vehicle is charging at the charging position on the driving route, the vehicle sets the power battery charging cut-off SOC to the corresponding required charging cut-off SOC.

5. A system for preventing thermal decay of brakes when a pure electric vehicle is heavily loaded downhill, comprising a processor, characterized in that: The processor is used to execute a computer program to achieve, based on the driving route input by the driver, the vehicle's unit distance power consumption on non-downhill sections on the corresponding driving route in historical data, and the power replenishment power recovered by the vehicle through braking feedback on the downhill section, to ensure that the vehicle can reach the end of the driving route, and to reversely calculate from the end of the driving route toward the starting point of the driving route to ensure that the power battery SOC at any position on the downhill section does not exceed the power battery SOC at the starting point of the driving route with a set upper limit, and output a recommended power battery SOC as the starting point of the driving route.

6. The system for preventing thermal decay of brakes when a pure electric vehicle is downhill with heavy load according to claim 5, characterized in that: Also based on the preset power battery power limit SOC, according to the vehicle's power consumption per unit distance on non-downhill sections on the corresponding driving route in historical data, and the power recovered by the vehicle through braking feedback on the downhill section, on the premise that the power battery of the vehicle has at least the power battery power limit SOC when it reaches the end of the driving route, and the power battery has at least the discharge cut-off SOC at each charging position in the driving route, the required power battery SOC required for the vehicle at each charging position in the driving route is calculated reversely from the end point of the driving route to the starting point, and the required power battery SOC is output as the required charging cut-off SOC for the corresponding charging position on the driving route.

7. The system for preventing thermal decay of brakes when a pure electric vehicle is downhill with heavy load according to claim 6, characterized in that: The starting point, the end point and the power battery power limit SOC are input through the vehicle's human-computer interaction interface and sent to the cloud server through the on-board communication device. The cloud server generates the driving route according to the starting point and the end point, calculates the recommended power battery SOC, the power battery feedback charging cut-off SOC corresponding to each charging position, and pushes them to the driver.

8. The system for preventing thermal decay of brakes when a pure electric vehicle is downhill with heavy load according to claim 7, characterized in that: The cloud server also sends the recommended power battery SOC and the power battery feedback charging cut-off SOC corresponding to each charging position to the vehicle; before the vehicle departs and is in the charging state, the vehicle sets the power battery charging cut-off SOC to the recommended power battery SOC; when the vehicle is charging at the charging position on the driving route, the vehicle sets the power battery charging cut-off SOC to the corresponding required charging cut-off SOC.

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