Battery pack temperature pre-adjusting system, control method, electric vehicle and medium

Abstract

The invention provides an electric vehicle battery pack temperature pre-adjusting system. The electric vehicle battery pack temperature pre-adjusting system comprises a battery pack, a heating element, a refrigerating element, a battery pack temperature sensor, an environment temperature sensor, an environment anemometer, a positioning element and a networking element. A vehicle owner can reserve the next starting time of the vehicle, and the vehicle performs thermal management processing in advance according to the external environment condition to ensure that the traveling vehicle is started smoothly. The influence of environment temperature and wind speed factors on the heat exchange of the battery pack is considered at the same time, the weather forecast information is corrected in combination with specific measured data, and the heat exchange proportion values at different wind speeds are calibrated in advance, so that the considered factors are comprehensive, scientific and reasonable, the battery pack pre-adjustment logic is simple, the use is convenient, and the working efficiency is improved. And the temperature of the battery pack can be adjusted in place at the reserved starting moment, and the advantages of high efficiency and energy conservation are achieved.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicles, and in particular to a battery pack temperature pre-regulation system, a control method, an electric vehicle and a medium. Background Art

[0002] Currently, electric vehicles are mainly powered by lithium-ion battery packs located on their chassis. The charging and discharging of lithium-ion battery packs need to be carried out in a suitable temperature environment. Although electric vehicles have certain thermal management functions during operation, when electric vehicles are parked for a long time in an environment with high or low ambient temperature, the temperature of the battery pack of the electric vehicle will tend to be consistent with the ambient temperature due to heat exchange with the surrounding environment. In this case, when the owner needs to start the vehicle again, the thermal management system of the electric vehicle will take a long time to adjust the temperature of the battery pack to a suitable range, which will inevitably affect the owner's car experience.

[0003] For example, an electric car using a lithium iron phosphate lithium-ion battery pack is parked outdoors in the cold overnight, and the owner needs to use the car the next morning. When the owner starts the vehicle, since the temperature of the battery pack is basically the same as the air temperature, the thermal management system of the electric car needs to work for a certain period of time to heat the battery pack temperature to an appropriate range and have full power output capability.

[0004] Therefore, it is urgent to develop battery pack temperature pre-adjustment technology so that car owners can pre-adjust the battery pack temperature to an appropriate range when starting electric vehicles parked in harsh climates such as high or low temperatures. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a battery pack temperature pre-regulation system, control method, electric vehicle and medium that are scientific and reasonable, simple in logic, easy to use, efficient and energy-saving, and take comprehensive factors into consideration.

[0006] According to a first aspect of the present invention, a system for pre-regulating the temperature of an electric vehicle battery pack is provided, which is used to adjust the temperature of an electric vehicle battery pack in a parked state to an appropriate range according to a time preset by the owner. The system includes a battery pack, a heating element, a cooling element, a battery pack temperature sensor, an ambient temperature sensor, an ambient anemometer, a positioning element, and a networking element, wherein:

[0007] The heating element and the cooling element are used to provide heating and cooling for the battery pack respectively;

[0008] The battery pack temperature sensor is used to measure the battery pack temperature;

[0009] The ambient temperature sensor and the ambient anemometer are used to measure the air temperature and wind speed of the external environment of the electric vehicle respectively;

[0010] The positioning element is used to obtain the geographical location of the electric vehicle;

[0011] The networking element is used for communication with the vehicle owner and for sending a query request to a weather forecast provider to obtain the temperature and wind speed information at the geographical location of the electric vehicle at a certain time.

[0012] Optionally, in the above-mentioned electric vehicle battery pack temperature pre-regulation system, the heating element is a PTC heater, and the heating power is constant.

[0013] Optionally, in the above-mentioned electric vehicle battery pack temperature pre-regulation system, the refrigeration element is an on-board air conditioner, and the refrigeration power is constant.

[0014] Optionally, in the above-mentioned electric vehicle battery pack temperature pre-regulation system, the positioning element is a satellite positioning chip.

[0015] Optionally, in the above-mentioned electric vehicle battery pack temperature pre-regulation system, the number of the battery pack temperature sensors is one or more. When the number of the battery pack temperature sensors is multiple, their arithmetic mean is used as the final measurement value.

[0016] Optionally, the above-mentioned electric vehicle battery pack temperature pre-regulation system also includes a controller, and the heating element, cooling element, battery pack temperature sensor, ambient temperature sensor, ambient anemometer, positioning element and networking element are all electrically connected to the controller.

[0017] According to a second aspect of the present invention, a control method for the temperature pre-regulation system of a battery pack of an electric vehicle as described above is provided. The method comprises: after the electric vehicle is parked, the owner makes an appointment with the electric vehicle for the next start time of the vehicle, and after the controller obtains the next start time of the vehicle, the following steps are performed in sequence:

[0018] Step S1, measuring and obtaining the ambient temperature T0 and the ambient wind speed V0, and obtaining the temperature t0 and the wind speed v0 of the location of the electric vehicle at the measurement time provided by the weather forecast provider through the networking component;

[0019] Step S2, obtaining the forecast temperature t1 and forecast wind speed v1 of the location of the electric vehicle at the next starting time provided by the weather forecast provider through the networking component;

[0020] Step S3, calculating the corrected temperature t2 and the corrected wind speed v2 at the location of the electric vehicle at the next starting time:

[0021] t2=t1+T0-t0 (1)

[0022] v2=v1+V0-v0 (2)

[0023] Step S4: Compare the corrected temperature t2 obtained in step S3 with the lower limit of the battery pack's permissible operating temperature T min And the upper limit of permissible operating temperature T max The size relationship between them: If T min ≤t2≤T max , then stop the execution of all subsequent steps, otherwise go to step S5;

[0024] Step S5, calculating the battery pack temperature pre-adjustment time τ:

[0025] If t2 <T min ,but:

[0026] τ=cm(T min -t2) / [P h -0.5k(T min -t2)] (3)

[0027] If t2>T max ,but:

[0028] τ=cm(t2-T max ) / [P r -0.5k(t2-T max )] (4)

[0029] The above t2 is the corrected temperature obtained in step S3, c and m are the average specific heat capacity and total mass of the battery pack, T min and T max are the lower and upper limits of the permissible operating temperature of the battery pack, respectively. h and P r are the heating power of the heating element and the cooling power of the cooling element, respectively, and k is the heat exchange ratio between the battery pack and the environment;

[0030] The value of the heat exchange ratio k is determined by the following method:

[0031] The controller pre-stores a table of heat exchange ratio values ​​between the battery pack and the environment at different wind speeds;

[0032] Based on the corrected wind speed v2 obtained in step S4, the two wind speed values ​​closest to it and their corresponding heat exchange ratio values ​​are found in the table;

[0033] The heat exchange ratio value corresponding to the corrected wind speed v2 is obtained by using the linear interpolation calculation method, which is the value of the heat exchange ratio k;

[0034] Step S6: At a time τ before the next start time, start pre-conditioning of the battery pack until the temperature of the battery pack is within the range of the lower limit and upper limit of the permissible operating temperature: If t2 <T min , then start heating the battery pack; if t2>Tmax , the battery pack cooling is started.

[0035] Optionally, in the control method of the electric vehicle battery pack temperature pre-regulation system, the values ​​of the heat exchange ratios at different wind speeds in the heat exchange ratio value table are obtained by testing by the following method before the vehicle leaves the factory:

[0036] The electric vehicle is placed in a wind tunnel with constant wind temperature. The battery pack is heated or cooled at constant power at a series of different wind speeds until the battery pack temperature remains stable. The battery pack temperature is recorded and the heat exchange ratio value at the corresponding wind speed is obtained by dividing the heating or cooling power by the absolute value of the difference between the wind temperature and the battery pack temperature.

[0037] According to a third aspect of the present invention, there is provided an electric vehicle equipped with the electric vehicle battery pack temperature pre-regulation system as described in any one of the above items.

[0038] Furthermore, the electric vehicle applies any of the above-mentioned control methods for the electric vehicle battery pack temperature pre-regulation system.

[0039] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium storing a plurality of control instructions, wherein the control instructions are suitable for loading by a processor to execute any of the above-mentioned control methods for the electric vehicle battery pack temperature pre-regulation system.

[0040] The beneficial effects of the technical solution of the present invention are introduced below in combination with the principle thereof.

[0041] The idea of ​​pre-regulating the battery pack temperature of the present invention is: after the electric car is parked, the owner makes an appointment for the next vehicle start time according to the vehicle usage needs; the battery pack temperature pre-regulation system heats or cools the battery pack in advance according to the ambient temperature and wind speed conditions at the vehicle start time, so that the temperature is adjusted to the lower limit or upper limit of the allowable operating temperature of the battery pack at the scheduled vehicle start time.

[0042] The above-mentioned pre-adjustment operation needs to be precise according to the actual situation: neither over-adjustment - the temperature is not allowed to exceed the lower limit of the battery pack's allowable operating temperature or fall below the upper limit of the allowable operating temperature too much, nor under-adjustment - ensure that the temperature is within the range from the lower limit to the upper limit of the battery pack's allowable operating temperature; neither early adjustment nor late adjustment - try to adjust it just in time when the vehicle starts, so as not to waste too much energy and at the same time without the owner having to wait.

[0043] Referring to step S5 of the technical solution of the present invention, the key to achieving accurate pre-adjustment operation is to accurately calculate the battery pack temperature pre-adjustment time τ, for which it is necessary to use heat transfer calculations and fully consider the meteorological conditions of the parking environment. According to the principle of heat transfer, under the premise of constant specific heat capacity, the temperature change of the battery pack is proportional to the change of its internal heat energy, and the change of the internal heat energy of the battery pack per unit time is equal to the difference between the heat generation power and the heat exchange power of the battery pack, where the heat generation power is the heating or cooling power of the battery pack itself, and the heat exchange power is the heat exchange power between the battery pack and the environment.

[0044] For example, if an electric vehicle is parked outdoors in the cold, the next time it is started, it needs to reach the lower limit of the battery pack's permissible operating temperature T min , and the corrected predicted value of the ambient temperature at startup is t2, the average specific heat capacity and total mass of the battery pack are c and m respectively, and the heating power of the heating element is P h Since the temperature pre-adjustment stage does not take very long, it is approximately assumed that the ambient temperature and wind speed remain unchanged during the entire temperature pre-adjustment process. According to the corrected wind speed prediction value v2, the heat exchange ratio between the battery pack and the environment at this wind speed is found to be k.

[0045] In the temperature pre-adjustment stage, the increase in heat energy in the battery pack = (battery pack heating power - battery pack heat dissipation power) * battery pack temperature pre-adjustment time, that is:

[0046] cm(T min -t2) = τ[P h -0.5k(T min -t2)]

[0047] The heat dissipation power of the battery pack is the product of the average value of the difference between the battery pack and the ambient temperature in the pre-adjustment stage and the heat exchange ratio. The ambient temperature in the pre-adjustment stage is constant at t2, and the battery pack temperatures at the start and end times are t2 and T2 respectively. min (Since the vehicle has been parked for a long time, the battery pack temperature is pre-adjusted to be consistent with the ambient temperature at the start time), the difference between the battery pack temperature and the ambient temperature at the start time and the end time is 0 and T respectively. min -t2, so the average value of the difference between the battery pack and the ambient temperature during the pre-adjustment process is 0.5*(0+T min -t2)=0.5(T min -t2).

[0048] Furthermore, in order to more accurately calculate the time τ required for pre-regulating the battery pack temperature, the technical solution of the present invention includes the following three important technical features.

[0049] First, the effects of ambient temperature and wind speed on the heat exchange power of the battery pack are taken into account at the same time. The atmosphere of the parking environment conducts convection heat exchange with the vehicle body and chassis, and indirectly exchanges heat with the battery pack. Under the same conditions, the greater the difference between the air temperature and the battery pack temperature, or the greater the wind speed, the stronger the heat exchange. Some well-known technical solutions in this field do not take into account the effect of ambient wind speed on the heat exchange of the battery pack, so they are not detailed and comprehensive enough.

[0050] Second, the difference between the environmental state of the specific parking location of the vehicle and the local weather forecast information is taken into account, and the weather forecast information is corrected according to this actual difference. As we all know, although today's weather forecast service providers can provide weather forecast information for a certain area based on satellite positioning data, their forecast information is general outdoor conditions, and there is often a certain difference between the temperature and wind speed of the actual specific parking location and the general outdoor meteorological conditions of its geographical location. For example, the weather forecast gives the temperature and wind speed information of a certain street, and the actual parking location may be in the outdoor parking lot of the street, or in the underground parking lot, or under a certain eaves or in the corner of the wall, so there is often a certain difference between the temperature and wind speed of the specific parking point and the general outdoor conditions of the local area. For this reason, in the technical solution of the present invention, after the owner issues the scheduled start time, the atmospheric temperature and wind speed of the parking location are measured immediately, and compared with the local weather information at the current time reported by the weather forecaster, the difference between the two is obtained, and the atmospheric temperature and wind speed forecast values ​​at the start time are corrected according to the difference.

[0051] Third, the heat exchange ratio k value under different wind speeds is tested and calibrated under controllable conditions in the laboratory before leaving the factory, and stored in the controller as a table for reference in advance, which is more targeted and makes the calculations required for the pre-adjustment operation process simpler and more accurate, and also provides technical ideas and means that are different from the known technology.

[0052] Therefore, the present invention simultaneously considers the effects of ambient temperature and wind speed factors on the heat exchange of the battery pack, corrects the weather forecast information in combination with specific measured data, and pre-calibrates the heat exchange ratio k value under different wind speeds. Therefore, the factors considered are comprehensive, scientific and reasonable, the battery pack pre-adjustment logic is simple and easy to use, and the battery pack temperature can be adjusted to the right place at the scheduled start time, which has the advantages of high efficiency and energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a flow chart of a control method of a temperature pre-regulation system for an electric vehicle battery pack in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0055] The present invention provides a temperature pre-regulation system for an electric vehicle battery pack, which is used to adjust the temperature of an electric vehicle battery pack in a parked state to an appropriate range according to a time preset by the owner. The system includes a battery pack, a heating element, a cooling element, a battery pack temperature sensor, an ambient temperature sensor, an ambient anemometer, a positioning element, and a networking element, wherein:

[0056] The heating element and the cooling element are used to provide heating and cooling for the battery pack respectively;

[0057] The battery pack temperature sensor is used to measure the battery pack temperature;

[0058] The ambient temperature sensor and the ambient anemometer are used to measure the air temperature and wind speed of the external environment of the electric vehicle respectively;

[0059] The positioning element is used to obtain the geographical location of the electric vehicle;

[0060] The networking element is used for communication with the vehicle owner and for sending a query request to a weather forecast provider to obtain the temperature and wind speed information at the geographical location of the electric vehicle at a certain time.

[0061] In one embodiment, the battery pack is arranged above the chassis of the electric vehicle, and the ambient temperature sensor and the ambient anemometer are arranged on the lower surface of the chassis of the electric vehicle.

[0062] Preferably, in the above-mentioned electric vehicle battery pack temperature pre-regulation system, the heating element is a PTC heater, and the heating power is constant.

[0063] Preferably, in the above-mentioned electric vehicle battery pack temperature pre-regulation system, the refrigeration element is an on-board air conditioner, and the refrigeration power is constant.

[0064] Preferably, the PTC heater and the vehicle air conditioner are both controlled by a battery thermal management system (BMS) and can be used to directly or indirectly heat and cool the battery pack.

[0065] Preferably, in the above-mentioned electric vehicle battery pack temperature pre-regulation system, the positioning element is a satellite positioning chip.

[0066] Specifically, the satellite positioning chip is a GPS and / or Beidou navigation chip.

[0067] Preferably, in the above-mentioned electric vehicle battery pack temperature pre-regulation system, the number of the battery pack temperature sensors is one or more. When the number of the battery pack temperature sensors is multiple, their arithmetic mean is used as the final measurement value.

[0068] Preferably, the above-mentioned electric vehicle battery pack temperature pre-regulation system also includes a controller, and the heating element, cooling element, battery pack temperature sensor, ambient temperature sensor, ambient anemometer, positioning element and networking element are all electrically connected to the controller.

[0069] Specifically, the controller is used to control the start and stop of the heating element and the cooling element, and to exchange information with the battery pack temperature sensor, the ambient temperature sensor, the ambient anemometer, the positioning element and the networking element.

[0070] In one embodiment, the controller is integrated into a vehicle controller.

[0071] The present invention also provides a control method applied to the above-mentioned electric vehicle battery pack temperature pre-regulation system. The method is that after the electric vehicle is parked, the owner makes an appointment with the electric vehicle for the next starting time of the vehicle.

[0072] In one embodiment, the car owner communicates with the controller of the electric car through the Internet via a mobile phone APP to inform the controller of the next start time of the vehicle.

[0073] After the controller obtains the next vehicle start time, it performs the following steps in sequence:

[0074] Step S1, measure and obtain the ambient temperature T0 and the ambient wind speed V0, and obtain the temperature t0 and the wind speed v0 of the location of the electric vehicle at the measurement time provided by the weather forecast provider through the networking component.

[0075] Step S2: obtaining the forecast temperature t1 and forecast wind speed v1 of the location of the electric vehicle at the next starting time provided by the weather forecast provider through the networking component.

[0076] Specifically, the controller obtains the current geographical location of the electric vehicle through the positioning element, and sends the geographical location together with the next starting time of the electric vehicle to the weather forecast provider through the Internet to request weather forecast service.

[0077] Step S3, calculating the corrected temperature t2 and the corrected wind speed v2 at the location of the electric vehicle at the next starting time:

[0078] t2=t1+T0-t0 (1)

[0079] v2=v1+V0-v0 (2)

[0080] Step S4: Compare the corrected temperature t2 obtained in step S3 with the lower limit of the battery pack's permissible operating temperature T min And the upper limit of permissible operating temperature T max The size relationship between them: If T min ≤t2≤T max, then stop the execution of all subsequent steps, otherwise go to step S5;

[0081] Step S5, calculating the battery pack temperature pre-adjustment time τ:

[0082] If t2 <T min ,but:

[0083] τ=cm(T min -t2) / [P h -0.5k(T min -t2)] (3)

[0084] If t2>T max ,but:

[0085] τ=cm(t2-T max ) / [P r -0.5k(t2-T max )] (4)

[0086] The above t2 is the corrected temperature obtained in step S3, c and m are the average specific heat capacity and total mass of the battery pack, T min and T max are the lower and upper limits of the permissible operating temperature of the battery pack, respectively. h and P r are the heating power of the heating element and the cooling power of the cooling element, respectively, and k is the heat exchange ratio between the battery pack and the environment;

[0087] The value of the heat exchange ratio k is determined by the following method:

[0088] The controller pre-stores a table of heat exchange ratio values ​​between the battery pack and the environment at different wind speeds;

[0089] Based on the corrected wind speed v2 obtained in step S4, the two wind speed values ​​closest to it and their corresponding heat exchange ratio values ​​are found in the table;

[0090] The heat exchange ratio value corresponding to the corrected wind speed v2 is obtained by using the linear interpolation calculation method, which is the value of the heat exchange ratio k.

[0091] Specifically, if the two wind speed values ​​closest to the corrected wind speed v2 are found in the table, they are v a and v b , where v a <v b , and v a and v b The corresponding heat exchange ratio values ​​are k a and k b , then the heat exchange ratio corresponding to the corrected wind speed v2 is:

[0092] k=ka +(k b -k a )*(v2-v a ) / (v b -v a )

[0093] Step S6: At a time τ before the next start time, start pre-conditioning of the battery pack until the temperature of the battery pack is within the range of the lower limit and upper limit of the permissible operating temperature: If t2 <T min , then start heating the battery pack; if t2>T max , the battery pack cooling is started.

[0094] Furthermore, in the control method of the electric vehicle battery pack temperature pre-regulation system, the values ​​of the heat exchange ratios at different wind speeds in the heat exchange ratio value table are obtained by testing by the following method before the vehicle leaves the factory:

[0095] The electric vehicle is placed in a wind tunnel with constant wind temperature. The battery pack is heated or cooled at constant power at a series of different wind speeds until the battery pack temperature remains stable. The battery pack temperature is recorded and the heat exchange ratio value at the corresponding wind speed is obtained by dividing the heating or cooling power by the absolute value of the difference between the wind temperature and the battery pack temperature.

[0096] In one embodiment, at a certain wind speed, the wind temperature is constant at 20°C, and the battery pack is heated at a constant power of 5kW through a resistance wire mesh uniformly pre-buried in the battery pack. After a period of testing, the battery pack temperature is stably maintained at 25°C, then the heat exchange ratio k at this wind speed = 5kW / |20°C-25°C| = 1kW / °C. The above heat exchange ratio value of 1kW / °C means that at a certain wind speed, when the temperature difference between the battery pack and the ambient temperature is 1°C, the heat exchange power between the battery pack and the environment is 1kW.

[0097] The present invention also provides an electric vehicle, which is equipped with the electric vehicle battery pack temperature pre-regulation system.

[0098] Furthermore, the electric vehicle applies the control method of the electric vehicle battery pack temperature pre-regulation system.

[0099] The present invention provides a computer-readable storage medium storing a plurality of control instructions, wherein the control instructions are suitable for being loaded by a processor to execute the control method of the above-mentioned electric vehicle battery pack temperature pre-regulation system.

[0100] It should be pointed out that the scope of application of the technical solution of the present invention takes into account the usual technical parameters and application scenarios of electric vehicles, that is, the heating power and cooling power are much smaller than the vehicle power required for starting and normal driving. Therefore, even when the temperature is very low or very high, the battery pack cannot supply power to the vehicle normally, but it can still meet the heating and cooling power consumption; and the pre-adjustment of the battery pack temperature generally takes less than 1 hour, so the pre-adjustment process approximately assumes that the ambient temperature and wind speed remain unchanged.

[0101] Example

[0102] Please refer to Figure 1 Three more specific embodiments are understood.

[0103] Example 1

[0104] This embodiment relates to a temperature pre-regulation system for an electric vehicle battery pack. A lithium iron phosphate lithium-ion battery pack is provided on the chassis of an electric vehicle. An ambient temperature sensor and an ambient anemometer are provided on the lower surface of the chassis of the electric vehicle. The heating element is a constant power P h =10kW PTC heater, the cooling element is a car air conditioner with constant power Pr=8kW, and the peak power during normal driving after the vehicle is started is 200kW. Among them, the PTC heating element is a PTC wire mesh coated on the battery casing, which is directly used to heat the battery; while the cooling element exchanges heat with the coolant in the liquid cooling plate at the bottom of the battery pack through a heat exchanger, thereby indirectly cooling the battery pack. There are 3 battery pack temperature sensors at different positions in the battery pack, and their arithmetic mean is used as the final battery pack temperature measurement output. The positioning element is a GPS chip, and the networking element is a 5G communication module. The controller electrically connected to the heating element, cooling element, battery pack temperature sensor, ambient temperature sensor, ambient anemometer, positioning element and networking element is integrated in the vehicle controller. The lower limit of the allowable operating temperature of the battery pack is T min =5℃, upper limit of permissible operating temperature T max =45℃, average specific heat capacity c=2000J / (kg·℃), total mass m=500kg.

[0105] Example 2

[0106] Based on Example 1, this embodiment relates to a control method of a temperature pre-regulation system for an electric vehicle battery pack in a cold environment.

[0107] The electric vehicle equipped with the electric vehicle battery pack temperature pre-regulation system in Example 1 was parked at 18:00 on a certain day, with the engine turned off and parked in an outdoor parking space. At 18:30, the owner made an appointment to use the vehicle at 08:00 the next morning through a smartphone APP. The controller then issued a command, measured the ambient temperature T0 = 6°C, the ambient wind speed V0 = 2.5m / s, and obtained the temperature t0 = 5°C and the wind speed v0 = 2.0m / s at the location of the electric vehicle at 18:30 given by the weather forecast provider through the networking component.

[0108] The controller obtains the forecast temperature t1=1℃ and the forecast wind speed v1=3.0m / s of the electric vehicle's location at 08:00 the next morning from the weather forecast provider through the networking components, and then calculates the corrected temperature t2=t1+T0-t0=1+6-5=2℃ of the electric vehicle's location at 08:00 the next morning. <T min , corrected wind speed v2=v1+V0-v0=3.0+2.5-2.0=3.5m / s.

[0109] From the table of heat exchange ratio values ​​between the battery pack and the environment at different wind speeds, it can be found that the heat exchange ratios between the battery pack and the environment at wind speeds of 3m / s and 4m / s are 1.5kW / ℃ and 2.5kW / ℃ respectively. Therefore, linear interpolation is used to calculate the corresponding heat exchange ratio k=1.5+(2.5-1.5)*(3.5-3) / (4-3)=2.0kW / ℃ at the corrected wind speed v2=3.5m / s.

[0110] Finally, the battery pack temperature pre-adjustment time τ is calculated as:

[0111] τ=cm(T min -t2) / [P h -0.5k(5-2)]=2000*500*(5-2) / [10000-0.5*2000*(5-2)]≈429s

[0112] Therefore, at 429s before 08:00 the next morning, the heating of the battery pack is started with a heating power of 10kW until the temperature of the battery pack reaches the lower limit of the allowable operating temperature of 5°C.

[0113] Example 3

[0114] Based on Example 1, this embodiment relates to a control method of a temperature pre-regulation system for an electric vehicle battery pack in a hot environment.

[0115] The electric vehicle equipped with the electric vehicle battery pack temperature pre-regulation system in Example 1 was parked at 8:00 on a certain day, with the engine turned off and parked in an outdoor parking space. At 8:30, the owner made a reservation for the vehicle at 14:00 through a smartphone APP. The controller then issued a command, measured the ambient temperature T0 = 43°C, the ambient wind speed V0 = 4.0 m / s, and obtained the temperature t0 = 42°C and the wind speed v0 = 3.5 m / s at the location of the electric vehicle at 8:30 given by the weather forecast provider through the networking component.

[0116] The controller obtains the forecast temperature t1=49℃ and forecast wind speed v1=3.0m / s at the location of the electric vehicle at 14:00 from the weather forecast provider through the networking components, and then calculates the corrected temperature t2=t1+T0-t0=49+43-42=50℃>T max , corrected wind speed v2=v1+V0-v0=3.0+4.0-3.5=3.5m / s.

[0117] From the table of heat exchange ratio values ​​between the battery pack and the environment at different wind speeds, it can be found that the heat exchange ratios between the battery pack and the environment at wind speeds of 3m / s and 4m / s are 1.5kW / ℃ and 2.5kW / ℃ respectively. Therefore, linear interpolation is used to calculate the corresponding heat exchange ratio k=1.5+(2.5-1.5)*(3.5-3) / (4-3)=2.0kW / ℃ at the corrected wind speed v2=3.5m / s.

[0118] Finally, the battery pack temperature pre-adjustment time τ is calculated as:

[0119] τ=cm(t2-T max ) / [P r -0.5k(t2-T max )]=2000*500*(50-45) / [8000-0.5*2000*(50-45)]≈

[0120] 1667s

[0121] Therefore, at 1667s before 14:00, the cooling of the battery pack is started with a cooling power of 8kW until the temperature of the battery pack reaches the upper limit of the allowable operating temperature of 45°C.

[0122] In the above-mentioned embodiment of the present invention, the influence of the ambient temperature and wind speed factors on the heat exchange of the battery pack is taken into consideration at the same time, the weather forecast information is corrected in combination with specific measured data, and the heat exchange ratio k value under different wind speeds is pre-calibrated. Therefore, the factors considered are comprehensive, scientific and reasonable, the battery pack pre-adjustment logic is simple and easy to use, and the battery pack temperature can be adjusted to the right place at the scheduled start time, which has the advantages of high efficiency and energy saving.

Claims

1. A temperature pre-regulation system for an electric vehicle battery pack, used to regulate the temperature of an electric vehicle battery pack in a parked state to an appropriate range according to a time preset by the owner, characterized in that: It includes a battery pack, a heating element, a cooling element, a battery pack temperature sensor, an ambient temperature sensor, an ambient anemometer, a positioning element, and a networking element, wherein: The heating element and the cooling element are used to provide heating and cooling for the battery pack respectively; The battery pack temperature sensor is used to measure the battery pack temperature; The ambient temperature sensor and the ambient anemometer are used to measure the air temperature and wind speed of the external environment of the electric vehicle respectively; The positioning element is used to obtain the geographical location of the electric vehicle; The networking element is used for communication with the vehicle owner and for sending a query request to a weather forecast provider to obtain the temperature and wind speed information at the geographical location of the electric vehicle at a certain time.

2. The electric vehicle battery pack temperature pre-regulation system according to claim 1, characterized in that: The heating element is a PTC heater, and the heating power is constant.

3. The electric vehicle battery pack temperature pre-regulation system according to claim 1, characterized in that: The refrigeration element is a vehicle-mounted air conditioner, and the refrigeration power is constant.

4. The electric vehicle battery pack temperature pre-regulation system according to claim 1, characterized in that: The positioning element is a satellite positioning chip.

5. The electric vehicle battery pack temperature pre-regulation system according to claim 1, characterized in that: The number of the battery pack temperature sensors is one or more. When the number of the battery pack temperature sensors is multiple, their arithmetic mean is taken as the final measurement value.

6. The electric vehicle battery pack temperature pre-regulation system according to claim 1, characterized in that: It also includes a controller, and the heating element, cooling element, battery pack temperature sensor, ambient temperature sensor, ambient anemometer, positioning element and networking element are all electrically connected to the controller.

7. The control method for the electric vehicle battery pack temperature pre-regulation system according to any one of claims 1 to 6 is characterized in that: After the electric vehicle is parked, the owner makes an appointment with the electric vehicle for the next start time of the vehicle. After the controller obtains the next start time of the vehicle, the following steps are performed in sequence: Step S1, measuring and obtaining the ambient temperature T0 and the ambient wind speed V0, and obtaining the temperature t0 and the wind speed v0 of the location of the electric vehicle at the measurement time provided by the weather forecast provider through the networking component; Step S2, obtaining the forecast temperature t1 and forecast wind speed v1 of the location of the electric vehicle at the next starting time provided by the weather forecast provider through the networking component; Step S3, calculating the corrected temperature t2 and the corrected wind speed v2 at the location of the electric vehicle at the next starting time: t2=t1+T0-t0 (1) v2=v1+V0-v0 (2) Step S4: Compare the corrected temperature t2 obtained in step S3 with the lower limit of the battery pack's permissible operating temperature T min And the upper limit of permissible operating temperature T max The size relationship between them: If T min ≤t2≤T max , then stop the execution of all subsequent steps, otherwise go to step S5; Step S5, calculating the battery pack temperature pre-adjustment time τ: If t2 <T min ,but: τ=cm(T min -t2) / [P h -0.5k(T min -t2)] (3) If t2>T max ,but: τ=cm(t2-T max ) / [P r -0.5k(t2-T max )] (4) The above t2 is the corrected temperature obtained in step S3, c and m are the average specific heat capacity and total mass of the battery pack, T min and T max are the lower and upper limits of the permissible operating temperature of the battery pack, respectively. h and P r are the heating power of the heating element and the cooling power of the cooling element, respectively, and k is the heat exchange ratio between the battery pack and the environment; The value of heat exchange ratio k is determined by the following method: The controller pre-stores a table of heat exchange ratio values ​​between the battery pack and the environment at different wind speeds; Based on the corrected wind speed v2 obtained in step S4, the two wind speed values ​​closest to it and their corresponding heat exchange ratio values ​​are found in the table; The heat exchange ratio value corresponding to the corrected wind speed v2 is obtained by using the linear interpolation calculation method, which is the value of the heat exchange ratio k; Step S6: At a time τ before the next start time, start pre-conditioning of the battery pack until the temperature of the battery pack is within the range of the lower limit and upper limit of the permissible operating temperature: If t2 <T min , the battery pack heating is started; if t2>T max , the battery pack cooling is started.

8. The control method of the electric vehicle battery pack temperature pre-regulation system according to claim 7, characterized in that: The values ​​of the heat exchange ratios at different wind speeds in the heat exchange ratio value table are obtained by testing the following method before the vehicle leaves the factory: The electric vehicle is placed in a wind tunnel with constant wind temperature. The battery pack is heated or cooled at constant power at a series of different wind speeds until the battery pack temperature remains stable. The battery pack temperature is recorded and the heat exchange ratio value at the corresponding wind speed is obtained by dividing the heating or cooling power by the absolute value of the difference between the wind temperature and the battery pack temperature.

9. An electric vehicle, characterized in that: The electric vehicle battery pack temperature pre-regulation system is equipped with any one of claims 1-6.

10. A computer-readable storage medium storing a plurality of control instructions, characterized in that: The control instruction is suitable for loading into a processor to execute the control method of the electric vehicle battery pack temperature pre-regulation system according to any one of claims 7 to 8.

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