阅读说明：本技术 一种电动汽车及其电池行车加热方法及装置 (Electric automobile and battery driving heating method and device thereof ) 是由 王勇士 赵宇斌 石赵伟 于 2020-06-12 设计创作，主要内容包括：本发明提供一种电动汽车及其电池行车加热方法及装置,属于新能源电动汽车领域。该加热方法包括：当前时刻电池的温度低于电池加热开启阈值时对电池进行加热；加热过程中电池的温度达到电池加热关闭阈值时停止对电池加热；电池加热开启、关闭阈值每个控制周期完成一次更新：根据控制周期内电池输出的最大放电电流和动力性能系数得到期望最大放电电流；根据预先确定的电池充放电电流和温度的对应关系以及期望最大放电电流,得到期望最大放电电流对应的温度,作为第一期望温度；根据第一期望温度得到电池加热开启阈值；根据电池加热开启阈值和阈值修正系数得到电池加热关闭阈值。该方法能满足车辆实际动力性和客户对车辆动力性的特殊需求。(The invention provides an electric automobile and a battery driving heating method and device thereof, and belongs to the field of new energy electric automobiles. The heating method comprises the following steps: heating the battery when the temperature of the battery at the current moment is lower than a battery heating starting threshold value; stopping heating the battery when the temperature of the battery reaches a battery heating closing threshold value in the heating process; the battery heating on and off threshold value is updated once in each control period: obtaining expected maximum discharge current according to the maximum discharge current output by the battery in the control period and the power performance coefficient; obtaining the temperature corresponding to the expected maximum discharge current as a first expected temperature according to the corresponding relation between the predetermined battery charge-discharge current and temperature and the expected maximum discharge current; obtaining a battery heating starting threshold value according to the first expected temperature; and obtaining a battery heating closing threshold according to the battery heating opening threshold and the threshold correction coefficient. The method can meet the actual dynamic property of the vehicle and the special requirements of customers on the dynamic property of the vehicle.)

1. A heating method for a battery traveling crane is characterized by comprising the following steps:

(1) collecting the temperature of the battery at the current moment;

(2) judging whether the temperature of the battery at the current moment is lower than a battery heating starting threshold value, and if so, heating the battery; judging whether the temperature of the battery reaches a battery heating closing threshold value in the heating process, and if so, stopping heating the battery;

in the driving process, the battery heating starting threshold and the battery heating stopping threshold are updated once in each control period, and the updating process is as follows:

obtaining expected maximum discharge current according to the maximum discharge current output by the battery in the control period and the power performance coefficient;

obtaining the temperature corresponding to the expected maximum discharge current as a first expected temperature according to the corresponding relation between the predetermined battery charge-discharge current and the temperature and the expected maximum discharge current;

obtaining a battery heating starting threshold according to the first expected temperature;

and obtaining a battery heating closing threshold according to the battery heating opening threshold and the threshold correction coefficient.

2. The battery driving heating method according to claim 1, wherein the updating process further comprises the steps of: adjusting the first expected temperature, and taking the adjusted first expected temperature as a battery heating starting threshold value; wherein the following steps are iteratively performed to adjust the first desired temperature: on the basis of the first expected temperature, when the energy of the battery, which can be converted into the vehicle power, is more than zero after the first set degree is increased, the first expected temperature is added with the first set degree until the energy of the battery, which can be converted into the vehicle power, is less than or equal to zero after the first set degree is increased, and the adjusted first expected temperature is obtained.

3. The battery driving heating method according to claim 1, wherein the updating process further comprises the steps of:

obtaining expected maximum charging current according to the maximum charging current output by the battery in the control period and the electric braking performance coefficient;

obtaining the temperature corresponding to the expected maximum charging current as a second expected temperature according to the corresponding relation between the predetermined battery charging and discharging current and the temperature and the expected maximum charging current;

comparing the first expected temperature with the second expected temperature, and taking the maximum value as the final expected temperature;

and obtaining a battery heating starting threshold according to the final expected temperature.

4. The battery driving heating method according to claim 3, wherein the updating process further comprises the steps of: adjusting the final expected temperature, and taking the adjusted final expected temperature as a battery heating starting threshold; wherein the following steps are iteratively performed to adjust the final desired temperature: on the basis of the final expected temperature, when the energy which can be converted into the vehicle power by the battery is more than zero after the second set degree is increased, the final expected temperature is added with the second set degree until the energy which can be converted into the vehicle power by the battery is less than or equal to zero after the second set degree is increased, and the adjusted final expected temperature is obtained.

5. The battery driving heating method according to claim 2 or 4, wherein the energy that the battery can convert into the vehicle power is obtained according to the available energy variation of the battery, the required heating capacity of the battery and the added heat dissipation energy of the battery every time the temperature of the battery rises to a set degree.

6. The battery driving heating method according to any one of claims 1 to 4, wherein the coefficient of dynamic performance ranges from 0.6 to 1.4.

7. A battery driving heating method according to claim 3 or 4, wherein the electric braking coefficient of performance ranges from 0.6 to 1.4.

8. A battery driving heating method according to any one of claims 1-4, wherein the battery heating start threshold is between 0 ℃ and 10 ℃, or the battery heating start threshold is between T1 and T2, T1 and T2 are obtained by querying a battery system peak charging and discharging current limit table, T1 is the battery temperature corresponding to the battery charging rate of 0.1C, T2 is the battery temperature corresponding to the battery charging rate of 0.5C, and the battery system peak charging and discharging current limit table is the corresponding relation between the battery charging and discharging capacity and the battery temperature and the battery SOC.

9. A battery cart heating apparatus comprising a processor and a memory, said processor executing a computer program stored by said memory to implement a battery cart heating method as claimed in any one of claims 1 to 8.

10. An electric vehicle comprising a power battery and a battery-powered vehicle heating device, wherein the battery-powered vehicle heating device comprises a processor and a memory, the processor executing a computer program stored by the memory to implement the battery-powered vehicle heating method of any one of claims 1-8.

Technical Field

The invention relates to an electric automobile and a battery driving heating method and device thereof, and belongs to the technical field of new energy electric automobiles.

Background

When the electric automobile runs in a low-temperature environment, the temperature of the battery is lower, the charging and discharging power of the battery is reduced, the dynamic property of the automobile is reduced, even the automobile cannot run, the kinetic energy recovery of the automobile is influenced, and the electric braking effect of the automobile is influenced. At present, the above problems are generally solved by heating the battery to avoid the temperature of the battery from being too low, and the existing battery driving heating methods include the following two methods:

(1) the method adopts a fixed heating starting threshold and a heating closing threshold, and heats the battery when the temperature of the battery is lower than the fixed heating starting threshold; when the battery temperature is above a fixed heat shut-off threshold, heating of the battery is stopped. Although the method is simple, the heating starting threshold value is set only according to traditional experience, the fixed and unchangeable threshold values are adopted for different vehicle running environments, the environmental adaptability is poor, and if the set heating starting threshold value is too high, batteries in certain regions are heated frequently, so that energy waste is caused.

(2) A dynamic threshold type driving heating method, for example, in the invention patent application document with application publication No. CN109830782A, discloses a driving heating control method for an electric vehicle battery, the method sets a plurality of standard minimum temperatures, each standard minimum temperature is provided with a corresponding heating opening temperature and a corresponding heating closing temperature, after the vehicle is powered on, firstly, the detected battery power-on temperature is compared with the historical power-on temperature, the minimum of the detected battery power-on temperatures is selected as the minimum power-on temperature, and then, the heating opening temperature and the heating closing temperature corresponding to the standard minimum temperature matched with the minimum power-on temperature are selected as the heating opening threshold and the heating closing threshold of the battery. The method introduces the historical electricity temperature of the battery when setting the threshold, reflects the influence of environmental factors on the threshold setting, can adapt to different environments, but fundamentally sets a plurality of fixed thresholds according to the traditional experience, then selects one more proper threshold from the plurality of fixed thresholds as the battery heating starting threshold, and does not realize the real dynamic setting of the threshold.

Therefore, the battery heating start threshold in the existing battery driving heating method is set only according to the traditional experience, and cannot be flexibly adjusted according to the actual operation condition of the vehicle and the requirements of customers on the vehicle dynamic property and the economical efficiency, so that the problem that the vehicle dynamic property and the economical efficiency are poor when the existing battery driving heating method is used for heating the battery is caused.

Disclosure of Invention

The invention aims to provide a battery driving heating method and a battery driving heating device, which are used for solving the problem that the power performance of a vehicle is poor due to unreasonable setting of a battery heating starting threshold in the conventional battery driving heating method; the invention also provides an electric automobile, which is used for solving the problem that the power performance of the automobile is poor when the battery is heated by the conventional battery running heating method.

In order to achieve the purpose, the invention provides a heating method for a battery traveling crane, which comprises the following steps:

(1) collecting the temperature of the battery at the current moment;

(2) judging whether the temperature of the battery at the current moment is lower than a battery heating starting threshold value, and if so, heating the battery; judging whether the temperature of the battery reaches a battery heating closing threshold value in the heating process, and if so, stopping heating the battery;

in the driving process, the battery heating starting threshold and the battery heating stopping threshold are updated once in each control period, and the updating process is as follows:

obtaining expected maximum discharge current according to the maximum discharge current output by the battery in the control period and the power performance coefficient;

obtaining the temperature corresponding to the expected maximum discharge current as a first expected temperature according to the corresponding relation between the predetermined battery charge-discharge current and the temperature and the expected maximum discharge current;

obtaining a battery heating starting threshold according to the first expected temperature;

and obtaining a battery heating closing threshold according to the battery heating opening threshold and the threshold correction coefficient.

The invention also provides a battery travelling crane heating device which comprises a processor and a memory, wherein the processor executes a computer program stored by the memory so as to realize the battery travelling crane heating method.

The invention also provides an electric automobile which comprises a power battery and a battery travelling crane heating device, wherein the battery travelling crane heating device comprises a processor and a memory, and the processor executes a computer program stored by the memory so as to realize the battery travelling crane heating method.

The invention has the beneficial effects that: the battery heating starting threshold value and the battery heating closing threshold value are updated once in each control period, factors in 3 aspects are comprehensively considered when the battery heating starting threshold value is updated, the factor 1 is the maximum discharge current output by the battery in the control period, and the value can change along with the time lapse and the actual driving working condition of the vehicle, so that the factor reflects the influence of the actual power output condition of the vehicle on the threshold value setting; factor 2 is a coefficient of power performance, which can be set according to the customer's specific requirements for vehicle dynamics, and therefore represents the influence of the customer's requirements on the threshold setting; factor 3 is a battery charge and discharge current limit table, which reflects the influence of the battery model on the threshold setting, since the table changes with the change of the battery model; in conclusion, the battery heating starting threshold value of the method is not set by the traditional experience, is not fixed and is updated in real time under the condition that the actual power output condition of the vehicle, the power demand of the customer on the vehicle and the 3 factors of the battery type are comprehensively considered, the battery heating starting threshold value is utilized to carry out battery heating control, the special requirements of the actual power performance of the vehicle and the customer on the power performance of the vehicle can be met, the method can be suitable for batteries of different types, and the application range is wider.

Further, in the electric vehicle and the method and the device for heating the battery of the electric vehicle during driving, the updating process further comprises the following steps: adjusting the first expected temperature, and taking the adjusted first expected temperature as a battery heating starting threshold value; wherein the following steps are iteratively performed to adjust the first desired temperature: on the basis of the first expected temperature, when the energy of the battery, which can be converted into the vehicle power, is more than zero after the first set degree is increased, the first expected temperature is added with the first set degree until the energy of the battery, which can be converted into the vehicle power, is less than or equal to zero after the first set degree is increased, and the adjusted first expected temperature is obtained.

The beneficial effects of doing so are: on the basis of first expected temperature, if continue to improve the battery temperature and be favorable to converting the electric quantity of battery into vehicle power, just heighten first expected temperature to the threshold value is opened as battery heating to the first expected temperature after will heightening, has further considered the influence of economic nature when carrying out battery heating and opening the threshold value setting, utilizes this battery heating to open the threshold value and carries out battery heating control, is favorable to taking into account vehicle dynamic nature and economic nature simultaneously.

Further, in the electric vehicle and the method and the device for heating the battery of the electric vehicle during driving, the updating process further comprises the following steps:

obtaining expected maximum charging current according to the maximum charging current output by the battery in the control period and the electric braking performance coefficient;

obtaining the temperature corresponding to the expected maximum charging current as a second expected temperature according to the corresponding relation between the predetermined battery charging and discharging current and the temperature and the expected maximum charging current;

comparing the first expected temperature with the second expected temperature, and taking the maximum value as the final expected temperature;

and obtaining a battery heating starting threshold according to the final expected temperature.

The beneficial effects of doing so are: when the battery heating starting threshold value is updated, 2 factors are added, namely the maximum charging current output by the battery in the control period and the electric brake performance coefficient. The maximum charging current output by the battery in the control period can change along with the time and the actual driving working condition of the vehicle, and the factor reflects the influence of the actual electric braking condition of the vehicle on the threshold value setting; the electric braking performance coefficient can be set according to the specific requirements of a customer on the electric braking effect of the vehicle, the influence of the customer demand on the threshold value setting is reflected by the factor, the battery heating control is carried out by utilizing the battery heating starting threshold value, and the vehicle dynamic property and the electric braking effect are favorably considered at the same time.

Further, in the electric vehicle and the method and the device for heating the battery of the electric vehicle during driving, the updating process further comprises the following steps: adjusting the final expected temperature, and taking the adjusted final expected temperature as a battery heating starting threshold; wherein the following steps are iteratively performed to adjust the final desired temperature: on the basis of the final expected temperature, when the energy which can be converted into the vehicle power by the battery is more than zero after the second set degree is increased, the final expected temperature is added with the second set degree until the energy which can be converted into the vehicle power by the battery is less than or equal to zero after the second set degree is increased, and the adjusted final expected temperature is obtained.

The beneficial effects of doing so are: on the basis of the final expected temperature, if the battery temperature is continuously increased to be beneficial to converting the electric quantity of the battery into the vehicle power, the final expected temperature is increased, the increased final expected temperature is used as a battery heating starting threshold, the influence of economy is further considered when the battery heating starting threshold is set, the battery heating starting threshold is utilized to carry out battery heating control, and the vehicle power, the electric braking effect and the economy are simultaneously considered.

Further, in order to judge the energy which can be converted into the vehicle power by the battery, in the electric vehicle and the battery driving heating method and device thereof, when the energy which can be converted into the vehicle power by the battery is set according to the temperature of the battery, the available energy variable of the battery, the heating electric quantity required by the battery and the heat dissipation energy added by the battery are obtained.

Further, in the electric vehicle and the battery driving heating method and device thereof, the value range of the power performance coefficient is 0.6-1.4.

Further, in the electric vehicle and the battery driving heating method and device thereof, the numeric area of the electric braking performance coefficient is 0.6-1.4.

Further, in the electric vehicle and the method and the device for heating the battery of the electric vehicle during driving, the battery heating start threshold is between 0 ℃ and 10 ℃, or the battery heating start threshold is between T1 and T2, T1 and T2 are obtained by querying a battery system peak charging and discharging current limit table, T1 is a battery temperature corresponding to a battery charging rate of 0.1C, T2 is a battery temperature corresponding to a battery charging rate of 0.5C, and the battery system peak charging and discharging current limit table is a corresponding relationship between a battery charging and discharging capacity and a battery temperature and a battery SOC.

Drawings

Fig. 1 is a schematic structural view of an electric vehicle in embodiment 1 of the present invention;

fig. 2 is a schematic structural view of a battery-powered vehicle heating device in embodiment 1 of the present invention;

fig. 3 is a flowchart of a threshold value updating process in embodiment 1 of the present invention;

fig. 4 is a schematic structural view of an electric vehicle in embodiment 2 of the invention;

fig. 5 is a flowchart of a threshold value updating process in embodiment 2 of the present invention;

fig. 6 is a flowchart of a threshold value updating process in embodiment 3 of the present invention.

Detailed Description

Embodiment mode 1

Embodiment 1 relates to an electric vehicle example, a battery running heating device example, and a battery running heating method example.

As shown in fig. 1, the electric vehicle of the present embodiment includes a power battery, a Battery Management System (BMS), a power coefficient of performance input device, a battery driving heater, and a battery heating device.

In the running process of the vehicle, the BMS monitors the temperature of the power battery in real time and sends the monitored temperature of the battery to a battery running heating device; the BMS also monitors the charging and discharging current output by the power battery in real time, and sends the maximum discharging current output by the battery in each control period (for example, 30 minutes, which can be specifically set according to actual needs) to the battery driving heating device in the control period; the vehicle driver inputs the power performance coefficient through the power performance coefficient input device, and the power performance coefficient input device sends the power performance coefficient input by the driver to the battery driving heating device; the battery driving heating device processes the received battery temperature, the maximum discharge current output by the battery and the power performance coefficient to realize the battery driving heating method of the embodiment, and further controls the heating or stopping of the heating of the battery; the battery heating equipment is responsible for heating the power battery, and the heating mode is not limited to resistor disc heating, liquid heating or current oscillation heating and the like.

In the present embodiment, the coefficient of power performance input device is a mechanical switch with different gears, each gear corresponds to a coefficient of power performance, and specifically, as shown in table 1, the larger the coefficient of power performance, the higher the requirement of the driver on the dynamic performance of the vehicle.

TABLE 1 Gear and Power Performance coefficient mapping Table

Gear position	1	2	3	4	5
						Coefficient of dynamic performance	0.6	0.8	1	1.2	1.4

As other embodiments, the power performance coefficient input device can also be a keyboard or a touch screen, and a driver can directly and manually input any numerical value in the value range of the power performance coefficient, wherein the value range of the power performance coefficient is 0.6-1.4.

The battery driving heating device of the present embodiment is shown in fig. 2, and the device includes a processor and a memory, and the processor executes a computer program stored in the memory to implement the battery driving heating method of the present embodiment.

The processor refers to a processing device such as a microprocessor MCU or a programmable logic device FPGA. The memory includes a physical device for storing information, and generally, information is digitized and then stored in a medium using an electric, magnetic, optical, or the like. For example: various memories for storing information by using an electric energy mode, such as RAM, ROM and the like; various memories for storing information by magnetic energy, such as hard disk, floppy disk, magnetic tape, magnetic core memory, bubble memory, and U disk; various types of memory, CD or DVD, that store information optically. Of course, there are other ways of memory, such as quantum memory, graphene memory, and so forth.

The battery driving heating method according to the present embodiment is described below, and the battery driving heating method may be implemented as a computer program that is stored in a memory and called when a processor runs. The method specifically comprises the following steps:

(1) collecting the temperature of the battery at the current moment; in the present embodiment, the temperature of the battery at the present time is provided by the BMS;

(2) judging whether the temperature of the battery at the current moment is lower than a battery heating starting threshold value, and if so, heating the battery; judging whether the temperature of the battery reaches a battery heating closing threshold value in the heating process, and if so, stopping heating the battery;

in the driving process, the battery heating on threshold and the battery heating off threshold are updated once in each control period, and the threshold updating process is as shown in fig. 3:

1) obtaining expected maximum discharge current according to the maximum discharge current output by the battery in the control period and the power performance coefficient; the desired maximum discharge current is equal to the power performance coefficient × the maximum discharge current output from the battery.

2) Obtaining a temperature corresponding to the expected maximum discharge current as a first expected temperature by inquiring a battery charge-discharge current limit table; each type of battery has a respective battery charging and discharging current limit table, and the table is a corresponding relation among the battery charging and discharging current, the battery temperature and the battery SOC (state of charge), and the corresponding relation can be obtained through experiments or simulation, so that the corresponding relation between the battery charging and discharging current and the temperature can be obtained from the battery charging and discharging current limit table; as another embodiment, the correspondence relationship between the battery charge/discharge current and the temperature may also be directly expressed in the form of a function, a curve, or the like, and is not limited to the one obtained from the battery charge/discharge current limit table.

3) Adjusting the first expected temperature, and taking the adjusted first expected temperature as a battery heating starting threshold value; specifically, the following steps are iteratively performed to adjust the first desired temperature: on the basis of the first expected temperature, when the energy of the battery, which can be converted into the vehicle power, is greater than zero after 1 ℃ is increased (namely a first set degree which can be adjusted according to actual needs), the first expected temperature is added with 1 ℃ until the energy of the battery, which can be converted into the vehicle power, is less than or equal to zero after the 1 ℃ is increased, and the adjusted first expected temperature is obtained.

For example, if the first desired temperature obtained in step 2) is 3 ℃, it is determined whether the energy that the battery can convert into vehicle power is greater than zero when the battery temperature is 3 ℃, and if so, it indicates that the battery temperature is increased to be beneficial for converting the electric quantity of the battery into vehicle power, i.e., the battery temperature is increased to be beneficial for improving the economy of the vehicle, at this time, 1 ℃ is added to the first desired temperature, and it is continuously determined whether the energy that the battery can convert into vehicle power is greater than zero when the battery temperature is 4 ℃ when the battery temperature is + 3 ℃ +1 ℃ + 4 ℃, and if so, it indicates that the battery temperature is increased to be not beneficial for improving the economy of the vehicle, and then the adjusted first desired temperature is 4 ℃.

The energy Q0 converted from the battery into the vehicle power is obtained according to the available energy variable Q1 of the battery, the required heating electric quantity Q2 of the battery and the increased heat dissipation energy Q3 of the battery when the temperature of the battery rises by 1 ℃ (namely, the set degree, and the value can be adjusted according to actual needs), wherein Q0 is Q1-Q2-Q3. If Q0 is greater than 0, it indicates that the battery temperature is increased to facilitate converting the battery charge into vehicle power, i.e. the increased battery temperature is beneficial to improve the vehicle economy; if Q0 < 0, it indicates that an increase in battery temperature is not favorable for improving vehicle economy. Wherein, Q1 can be obtained by inquiring the temperature-available energy MAP table of the power battery; q2 can be obtained by heating experimental data of batteries of different types, and the value is mainly influenced by the specific heat capacity and the heat conductivity of the battery, for example, when a certain type of battery is heated, the temperature rises by 1 ℃ every time, and the consumed electric quantity is 0.5 kWh; q3 is the amount of heat dissipation energy increase of the battery every 1 ℃ when the battery rises corresponding to the ambient temperature of the battery in each control period, and the value is mainly influenced by the heat preservation performance of the battery and the temperature difference between the battery and the environment, and can be obtained through experimental data, for example, the battery temperature of a certain type of battery is 2 ℃ when the ambient temperature is-10 ℃, the temperature rise of the battery is 1 ℃, the temperature difference is increased from 12 ℃ to 13 ℃, the heat dissipation energy increase is 0.1kWh in the control period, and the like.

4) And obtaining a battery heating closing threshold according to the battery heating opening threshold and the threshold correction coefficient. And the battery heating off threshold value is equal to the battery heating on threshold value plus the threshold value correction coefficient.

The threshold correction coefficient is set according to actual needs, as long as the difference between the battery heating opening threshold and the battery heating closing threshold (hereinafter referred to as the difference between the opening threshold and the closing threshold) is greater than the accuracy of the temperature sensor of the electric vehicle battery system, and generally, the difference between the opening threshold and the closing threshold is preferably not less than twice the detection accuracy of the temperature sensor, so as to prevent the heating from being frequently opened and closed due to the detection error of the temperature sensor, and the service life of the electric vehicle battery heating system is not affected. The threshold correction factor is typically an integer, such as 2 ℃ or 4 ℃.

When the battery heating starting threshold value is updated by the battery driving heating method of the embodiment, factors in 4 aspects are comprehensively considered, wherein the factor 1 is the maximum discharge current output by the battery in the control period, and the value can change along with the time and the actual driving working condition of the vehicle, so that the influence of the actual power output condition of the vehicle on the threshold value setting is reflected by the factor; factor 2 is a coefficient of power performance, which can be set according to the customer's specific requirements for vehicle dynamics, and therefore represents the influence of the customer's requirements on the threshold setting; factor 3 is a battery charge and discharge current limit table, which reflects the influence of the battery model on the threshold setting, since the table changes with the change of the battery model; the factor 4 is the energy that the battery can convert into the vehicle power, and the value can reflect whether the increase of the battery temperature is beneficial to converting the electric quantity of the battery into the vehicle power, namely whether the increase of the battery temperature is beneficial to improving the vehicle economy, so that the factor reflects the influence of the vehicle economy on the threshold value setting; in conclusion, the battery heating starting threshold value of the method is not set by the traditional experience, is not fixed and is updated in real time under the condition that 4 factors including the actual power output condition of the vehicle, the power demand of a customer on the vehicle, the battery type and the vehicle economy are comprehensively considered, the battery heating starting threshold value is used for battery heating control, the special requirements of the actual power performance of the vehicle and the customer on the power performance of the vehicle can be met, the method is suitable for batteries of different types, the application range is wider, and meanwhile, the power performance and the economy of the vehicle can be considered.

As another embodiment, the updating process may also omit step 3), and directly use the first desired temperature obtained in step 2) as the battery heating-on threshold.

As another embodiment, in order to add a redundant protection to the battery heating start, the battery heating start threshold may be set between 0 ℃ and 10 ℃, and when the battery heating start threshold obtained in step 3) is less than 0 ℃, 0 ℃ is used as the final battery heating start threshold to prevent frequent heating start; when the battery heating starting threshold obtained in the step 3) is larger than 10 ℃, taking the 10 ℃ as a final battery heating starting threshold to prevent untimely heating; when the battery heating starting threshold obtained in the step 3) is between 0 ℃ and 10 ℃, taking the battery heating starting threshold obtained in the step 3) as a final battery heating starting threshold.

As another embodiment, in order to add a redundant protection to whether the battery is heated up or not, the battery heating-up start threshold may be between T1 and T2, and when the battery heating-up start threshold obtained in step 3) is less than T1, T1 is used as the final battery heating-up start threshold to prevent the heating from being frequently started up; when the battery heating starting threshold obtained in the step 3) is larger than T2, taking T2 as a final battery heating starting threshold to prevent untimely heating; when the battery heating-on threshold obtained in the step 3) is between T1 and T2, the battery heating-on threshold obtained in the step 3) is taken as a final battery heating-on threshold. The battery system peak value charging and discharging current limit tables are inquired to obtain T1 and T2, T1 is the corresponding battery temperature when the battery charging multiplying factor is 0.1C, T2 is the corresponding battery temperature when the battery charging multiplying factor is 0.5C, each type of battery has the corresponding battery system peak value charging and discharging current limit table, and the tables are the corresponding relations among the battery charging and discharging capacity, the battery temperature, the battery SOC and other parameters. In another embodiment, the charging rates corresponding to T1 and T2 may be adjusted according to actual needs.

In the embodiment, the value range of the power performance coefficient is 0.6-1.4, and the expected maximum discharge current is equal to the power performance coefficient multiplied by the maximum discharge current output by the battery; as another embodiment, the value range of the power performance coefficient may also be adjusted according to actual needs, and the expected maximum discharge current may also be equal to the power performance coefficient plus the maximum discharge current output by the battery. In addition, the battery heating-off threshold value can also be equal to the battery heating-on threshold value multiplied by a threshold correction coefficient, the threshold correction coefficient is set according to actual needs, and only the difference value between the battery heating-on threshold value and the battery heating-off threshold value is ensured to be larger than the accuracy of the temperature sensor of the battery system of the electric automobile.

In another embodiment, the maximum discharge current of the battery in the control period may be obtained by the BMS sending the battery discharge current in the control period to the battery driving heater and processing the battery discharge current by the battery driving heater.

Embodiment mode 2

Embodiment 2 relates to an electric vehicle example, a battery running heating device example, and a battery running heating method example.

As shown in fig. 4, the electric vehicle according to the present embodiment differs from embodiment 1 in that: firstly, an electric braking performance coefficient input device is added to the electric automobile, a vehicle driver inputs an electric braking performance coefficient through the electric braking performance coefficient input device, and the electric braking performance coefficient input device sends the electric braking performance coefficient input by the driver to a battery service heating device; secondly, each control period of the BMS of the electric automobile also sends the maximum charging current output by the battery in the control period to a battery driving heating device; the battery driving heating device processes the received battery temperature, the maximum discharge current output by the battery, the maximum charge current output by the battery, the power performance coefficient and the electric braking performance coefficient to realize the battery driving heating method of the embodiment, and further controls the heating or stopping of the heating of the battery.

In this embodiment, the electric brake coefficient of performance input device is a mechanical switch with different gears, each gear corresponds to one electric brake coefficient of performance, and specifically, as shown in table 2, the larger the electric brake coefficient of performance, the higher the requirement of the driver on the electric braking effect of the vehicle.

TABLE 2 Gear and electric brake performance coefficient corresponding table

Gear position	1	2	3	4	5
						Coefficient of performance of electric brake	0.6	0.8	1	1.2	1.4

As other embodiments, the electric braking performance coefficient input device may also be a keyboard or a touch screen, and a driver may directly and manually input any value within a value range of the electric braking performance coefficient, where the value range of the electric braking performance coefficient is 0.6-1.4.

In this embodiment, the coefficient of dynamics input means and the coefficient of electric brake performance input means are provided separately, and as another embodiment, these two means may be combined into one means.

The battery-powered vehicle heating apparatus of the present embodiment has the same configuration as that of embodiment 1, except that: the battery-powered vehicle heating method that can be realized by the battery-powered vehicle heating device of the present embodiment is different from that of embodiment 1.

The following describes a battery driving heating method of the present embodiment, which includes the steps of:

(1) collecting the temperature of the battery at the current moment; in the present embodiment, the temperature of the battery at the present time is provided by the BMS;

(2) judging whether the temperature of the battery at the current moment is lower than a battery heating starting threshold value, and if so, heating the battery; judging whether the temperature of the battery reaches a battery heating closing threshold value in the heating process, and if so, stopping heating the battery;

in the driving process, the battery heating on threshold and the battery heating off threshold are updated once in each control cycle, and the threshold updating process is as shown in fig. 5:

1) obtaining expected maximum discharge current according to the maximum discharge current output by the battery in the control period and the power performance coefficient; the desired maximum discharge current is equal to the power performance coefficient × the maximum discharge current output from the battery.

2) Obtaining a temperature corresponding to the expected maximum discharge current as a first expected temperature by inquiring a battery charge-discharge current limit table;

3) obtaining expected maximum charging current according to the maximum charging current output by the battery in the control period and the electric braking performance coefficient; the desired maximum charging current is equal to the electric brake performance coefficient × the maximum charging current output by the battery.

4) Obtaining the temperature corresponding to the expected maximum charging current as a second expected temperature by inquiring a battery charging and discharging current limit table;

5) comparing the first expected temperature with the second expected temperature, and taking the maximum value as the final expected temperature;

6) taking the final expected temperature as a battery heating starting threshold;

7) and obtaining a battery heating closing threshold according to the battery heating opening threshold and the threshold correction coefficient. And the battery heating off threshold value is equal to the battery heating on threshold value plus the threshold value correction coefficient.

The threshold correction coefficient is set according to actual needs, as long as the difference between the battery heating opening threshold and the battery heating closing threshold (hereinafter referred to as the difference between the opening threshold and the closing threshold) is greater than the accuracy of the temperature sensor of the electric vehicle battery system, and generally, the difference between the opening threshold and the closing threshold is preferably not less than twice the detection accuracy of the temperature sensor, so as to prevent the heating from being frequently opened and closed due to the detection error of the temperature sensor, and the service life of the electric vehicle battery heating system is not affected. The threshold correction factor is typically an integer, such as 2 ℃ or 4 ℃.

When the battery heating starting threshold value is updated by the battery driving heating method of the embodiment, factors in the aspect of 5 are comprehensively considered, wherein the factor 1 is the maximum discharge current output by the battery in the control period, and the value can change along with the time and the actual driving working condition of the vehicle, so that the influence of the actual power output condition of the vehicle on the threshold value setting is reflected by the factor; factor 2 is a coefficient of power performance, which can be set according to the customer's specific requirements for vehicle dynamics, and therefore represents the influence of the customer's requirements on the threshold setting; factor 3 is a battery charge and discharge current limit table, which reflects the influence of the battery model on the threshold setting, since the table changes with the change of the battery model; the factor 4 is the maximum charging current output by the battery in the control period, the value can change along with the time and the actual driving condition of the vehicle, and the factor reflects the influence of the actual electric braking condition of the vehicle on the threshold value setting; factor 5 is an electric braking performance coefficient, which can be set according to the specific requirements of a customer on the electric braking effect of the vehicle, and reflects the influence of the customer requirements on the threshold setting; in conclusion, the battery heating starting threshold value of the method is updated in real time under the condition that the actual power output condition and the actual electric braking condition of the vehicle, the requirements of customers on the dynamic property and the electric braking effect of the vehicle and 5 factors of the battery type are comprehensively considered, the battery heating starting threshold value is utilized to carry out battery heating control, the special requirements of the actual dynamic property and the customers on the dynamic property of the vehicle can be met, the special requirements of the actual electric braking property and the customers on the electric braking effect of the vehicle can also be met, meanwhile, the method is suitable for batteries of different types, and the application range is wider.

Embodiment 3

Embodiment 3 relates to an electric vehicle example, a battery running heating device example, and a battery running heating method example.

The structure of the electric vehicle and the structure of the battery-powered heating device according to the present embodiment are the same as those of embodiment 2, except that: the electric vehicle and the battery running heating device according to the present embodiment are different from those according to embodiment 2 in terms of the method of heating the battery running.

The following describes a battery driving heating method of the present embodiment, which includes the steps of:

(1) collecting the temperature of the battery at the current moment; in the present embodiment, the temperature of the battery at the present time is provided by the BMS;

(2) judging whether the temperature of the battery at the current moment is lower than a battery heating starting threshold value, and if so, heating the battery; judging whether the temperature of the battery reaches a battery heating closing threshold value in the heating process, and if so, stopping heating the battery;

in the driving process, the battery heating on threshold and the battery heating off threshold are updated once in each control cycle, and the threshold updating process is as shown in fig. 6:

1) obtaining expected maximum discharge current according to the maximum discharge current output by the battery in the control period and the power performance coefficient; the desired maximum discharge current is equal to the power performance coefficient × the maximum discharge current output from the battery.

2) Obtaining a temperature corresponding to the expected maximum discharge current as a first expected temperature by inquiring a battery charge-discharge current limit table;

3) obtaining expected maximum charging current according to the maximum charging current output by the battery in the control period and the electric braking performance coefficient; the desired maximum charging current is equal to the electric brake performance coefficient × the maximum charging current output by the battery.

4) Obtaining the temperature corresponding to the expected maximum charging current as a second expected temperature by inquiring a battery charging and discharging current limit table;

5) comparing the first expected temperature with the second expected temperature, and taking the maximum value as the final expected temperature;

6) adjusting the final expected temperature, and taking the adjusted final expected temperature as a battery heating starting threshold value; specifically, the following steps are iteratively performed to adjust the final desired temperature: on the basis of the final expected temperature, when the energy which can be converted into the vehicle power by the battery is more than zero after 1 ℃ is increased (namely a second set degree which can be adjusted according to actual needs), the final expected temperature is added with 1 ℃ until the energy which can be converted into the vehicle power by the battery is less than or equal to zero after the 1 ℃ is increased, and the adjusted final expected temperature is obtained.

7) And obtaining a battery heating closing threshold according to the battery heating opening threshold and the threshold correction coefficient. And the battery heating off threshold value is equal to the battery heating on threshold value plus the threshold value correction coefficient.

The threshold correction coefficient is set according to actual needs, as long as the difference between the battery heating opening threshold and the battery heating closing threshold (hereinafter referred to as the difference between the opening threshold and the closing threshold) is greater than the accuracy of the temperature sensor of the electric vehicle battery system, and generally, the difference between the opening threshold and the closing threshold is preferably not less than twice the detection accuracy of the temperature sensor, so as to prevent the heating from being frequently opened and closed due to the detection error of the temperature sensor, and the service life of the electric vehicle battery heating system is not affected. The threshold correction factor is typically an integer, such as 2 ℃ or 4 ℃.

The difference between the battery-powered vehicle heating method of the present embodiment and embodiment 2 is that the final desired temperature is also adjusted when the battery heating-on threshold is updated, if the battery temperature is further increased on the basis of the final desired temperature, which is favorable for converting the electric quantity of the battery into the vehicle power, the final desired temperature is increased, and the increased final desired temperature is used as the battery heating-on threshold, and the battery heating-on threshold is set in consideration of the economic effect.