CN116565401A

CN116565401A - Battery temperature control method and device, storage medium and BMS battery system

Info

Publication number: CN116565401A
Application number: CN202310530745.8A
Authority: CN
Inventors: 马翔
Original assignee: United Automotive Electronic Systems Co Ltd
Current assignee: United Automotive Electronic Systems Co Ltd
Priority date: 2023-05-12
Filing date: 2023-05-12
Publication date: 2023-08-08

Abstract

The invention relates to the technical field of automobile battery management, in particular to a battery temperature control method, a device, a storage medium and a BMS battery system. The temperature of the battery is controlled by adopting a PID closed-loop control algorithm, and the PID closed-loop control algorithm can adjust the temperature of the cooling liquid in real time according to feedback temperature information of the output cooling liquid; the parameters of PID output are continuously changed, and compared with the traditional table look-up type cooling liquid temperature adjustment, the characteristics of continuous change of the working power of the heat management controller and the water pump can be fully utilized, so that energy sources are better saved; meanwhile, the huge workload of manufacturing a thermal management system control demand matrix table is saved; the invention can also respectively provide different initialization PID control parameters according to the possible environment of the battery of the electric automobile during actual running, thereby improving the control efficiency and effect.

Description

Battery temperature control method and device, storage medium and BMS battery system

Technical Field

The invention relates to the technical field of automobile battery management, in particular to a battery temperature control method, a device, a storage medium and a BMS battery system.

Background

The majority of automobile manufacturers are greatly developing new energy automobiles, and the performance of the power battery serving as a key component of an electric automobile directly influences the use experience of the whole automobile, such as endurance mileage, acceleration performance, charging speed, spontaneous combustion risk, service life and the like.

The allowable charge and discharge power of the power battery is different at different temperatures, and the maximum charge and discharge power can be exerted only in a certain temperature interval, as shown in fig. 4, so that the power performance and the charging speed of the whole vehicle can be influenced by the fact that the temperature of the power battery is too high or too low. In addition, if the temperature of the power battery is too high and cannot be effectively controlled, thermal runaway is caused, spontaneous combustion risks exist, and the safety of the whole vehicle is affected; and when the temperature of the power battery is too low, the battery can be charged and discharged frequently, lithium dendrites can be generated, and the service life of the battery is influenced.

In order to maintain the state of the power battery, the use experience of the electric vehicle is improved, and most middle-high-end electric vehicles are provided with a power battery thermal management system. The heat management system can heat and cool the circulating cooling liquid which is introduced into the battery pack through the heating and cooling mechanism respectively at low temperature and high temperature, meanwhile, the flow of the cooling liquid is controlled through the water pump, and the cooling liquid flows into the battery pack to heat and cool the battery pack, so that the flow of the water pump and the power of the heating and cooling mechanism are key requirements of the heat management system.

The structure of the conventional power battery thermal management system is shown in fig. 5. The working principle is that the control demand matrix table of the thermal management system is inquired under different environment temperatures and whole vehicle working conditions, and the flow of the water pump and the power of the heating and cooling mechanism are controlled according to the control demand matrix table of the thermal management system. The thermal management system control demand matrix table is shown in the following table:

the table is a calibration result of heating at 25 ℃ below zero and cooling at 40 ℃, in addition, the required parameters at different ring temperatures are required to be calibrated, a plurality of tables are formed, and the flow and the power are controlled in sections according to the tables.

The temperature change process during the heating function of the conventional thermal management system is shown in fig. 6: when the ambient temperature is low, the temperature of the power battery can be consistent with the ambient temperature after the vehicle is kept stand for a long time, for example, the vehicle is parked for one day in an environment of minus 30 ℃, and the temperature of the power battery can be about minus 30 ℃. At this time, as shown in fig. 4, the battery charge and discharge power is very low. When the thermal management system monitors that the temperature of the battery is lower than a calibrated threshold value after the vehicle is started, the heating device is controlled to heat the cooling liquid to enter the battery pack to heat the battery core. When the battery temperature reaches the temperature at which the heating function is stopped, the water pump and the heating mechanism are stopped, and the battery temperature can be slowly reduced due to the low external environment temperature until the temperature reaches the heating starting temperature threshold value, and the cycle is repeated. It can be seen that, in order to raise the battery temperature to a suitable interval as soon as possible at low temperature, the battery temperature will enter the heating function in advance when the temperature is low, which results in a lower temperature threshold calibration for entering the heating function, so after the heating is stopped, the battery temperature will be lowered to a lower temperature to enter the heating again, which is unfavorable for maintaining the battery temperature within a fixed range.

The temperature change process during the cooling function of the conventional thermal management system is shown in fig. 7: when the ambient temperature is high, the temperature of the power battery can be consistent with the ambient temperature after the vehicle is kept stand for a long time, for example, the vehicle is parked for one day at the ambient temperature of 40 ℃, and the temperature of the power battery can be about 40 ℃. In addition, the power battery itself generates heat when charged and discharged, and even if the ambient temperature is 20 degrees, there may be a problem in that the power battery temperature is too high. When the temperature of the power battery rises to more than 45 degrees due to the ambient temperature and self-charging and discharging, the battery charging and discharging power is very low according to the figure 1. When the thermal management system monitors that the temperature of the battery is higher than a certain threshold value after the vehicle is started, the cooling mechanism is controlled to reduce the temperature of cooling liquid to enter the battery pack to cool the battery cell. When the temperature of the battery reaches the temperature of the cooling function, the water pump and the heating mechanism are stopped, if the charging and discharging are continued, the temperature of the battery is slowly increased until the temperature reaches the temperature threshold value of entering cooling due to heat generated by the battery and heat radiation of the external environment, and the cycle is performed. In order to save energy, the cooling is considered to be carried out when the temperature is slightly higher than a few degrees.

In summary, the existing temperature control method of the power battery thermal management system is a sectional open loop control, and the method has several disadvantages:

1. and the scanning points are calibrated under different environment temperatures and different working conditions to obtain the heat management required flow and power under different working conditions, a plurality of tables similar to the table 1 are required to be calibrated, and the workload is huge. Considering that a single charge and discharge can take a long time, for example, a large part of vehicle types can be slowly charged for at least 6 hours at one time, and the whole calibration period is very long;

2. in order to reduce the workload as much as possible, the calibration cannot cover all working conditions, so that the final calibrated thermal management required flow and power are segmented according to the temperature, the characteristics of a continuous water pump and a heating and cooling mechanism with continuously variable power cannot be fully utilized, and the heating or cooling effect is poor when the continuous water pump and the heating and cooling mechanism with continuously variable power are controlled in a segmented manner, and the heating or cooling effect is possibly poor when the continuous water pump and the heating and cooling mechanism are excessively heated or cooled under other working conditions, so that energy is wasted;

3. the charging working condition is calibrated in the windless environment cabin, the temperature change caused by rapid ventilation of the surrounding air of the battery pack during high wind is not considered, and the high wind information cannot be transmitted to the controller. Although the battery pack is generally not in direct contact with the outside, practical experiments find that strong wind also has an influence on the cooling of the battery pack. For example, in low-temperature windy weather, the battery pack is cooled obviously faster than the windless environment at the same environment temperature, and at this time, the heating requirement of the windless environment calibration is inappropriate, which may cause the battery temperature to fail to rise, and the battery pack always operates in a temperature interval with low efficiency as shown in fig. 8, resulting in failure of temperature control.

Disclosure of Invention

The invention discloses a battery temperature control method, a device, a storage medium and a BMS battery system, which can continuously control the temperature of a battery within a preset temperature range, and remarkably improve the service efficiency of the battery and the service life of the battery.

In order to achieve the above object, in one aspect, a battery temperature control method is provided, including: a battery temperature acquisition step, a cooling liquid adjustment step and a parameter initialization step; wherein,,

a battery temperature acquisition step, namely acquiring the actual temperature of a battery;

a cooling liquid adjusting step, according to the actual temperature of the battery, adjusting the temperature of cooling liquid entering the battery by adopting a PID closed-loop control algorithm, so that the cooling liquid exchanges heat with the battery;

and initializing parameters, namely initializing control parameters of a PID closed-loop control algorithm, wherein the specific initialization value of the PID control parameters is determined by the current battery operation mode.

The embodiment has the advantages that the PID closed-loop control algorithm can adjust the temperature of the cooling liquid in real time according to the feedback temperature information of the output cooling liquid; the parameters of PID output are continuously changed, and compared with the traditional table look-up type cooling liquid temperature adjustment, the characteristics of continuous change of the working power of the heat management controller and the water pump can be fully utilized, so that energy sources are better saved; meanwhile, the huge workload of manufacturing a thermal management system control demand matrix table is saved; the invention can also respectively provide different initialization PID control parameters according to the possible environment of the battery of the electric automobile during actual running, thereby improving the control efficiency and effect.

Further, the method also comprises a control intervention judging step, wherein the control intervention judging step is positioned before the cooling liquid adjusting step;

a control intervention judging step, firstly judging whether the battery is at high voltage or not, and if the battery is not at high voltage, terminating temperature control;

if the battery is at high voltage, judging whether the actual temperature of the battery reaches a heating condition or a refrigerating condition, if the actual temperature of the battery reaches the heating condition or the refrigerating condition, starting a cooling liquid adjusting step, otherwise, stopping temperature control.

Specifically, the PID closed loop control algorithm controls the inlet temperature of the coolant by adjusting the operating power of the thermal management controller.

The embodiment has the advantages that the temperature of the cooling liquid entering the battery can be controlled by adjusting the working power of the thermal management controller, the purpose of controlling the temperature of the battery is achieved, and the invention is applicable to all vehicle types with the thermal management controller and has strong universality.

Further, the PID closed-loop control algorithm also controls the inlet flow of the cooling liquid by adjusting the working power of the water pump.

The advantage of this embodiment is that for extreme environments or situations where a fast regulation of the battery temperature is required, the speed of regulating the battery temperature can be increased and the battery temperature regulating effect can be improved by the dual control of the water pump and the regulating thermal management controller.

Further, the method also comprises a control exit judging step, wherein the control exit judging step is used for judging whether the actual temperature of the current battery reaches an exit condition, and if the current battery reaches the exit condition, the cooling liquid adjusting step is stopped.

Specifically, the heating conditions are: whether the actual temperature of the battery is less than a first starting threshold;

the refrigeration conditions are as follows: whether the actual temperature of the battery is greater than a second starting threshold;

the exit conditions comprise a heating exit condition and a refrigerating exit condition;

the heating exit conditions are as follows: the actual temperature is greater than a first end threshold;

the refrigeration exit conditions are as follows: the actual temperature is less than the second end threshold.

Specifically, the first starting threshold, the first ending threshold, the second starting threshold and the second ending threshold are all determined according to the battery model and the temperature corresponding to the highest power of the battery charge and discharge.

This embodiment has the advantage that the start or stop of the regulation of the cooling fluid can be judged according to the actual temperature of the battery and the desired optimal temperature interval, and the control logic is simple.

Further, the heating condition, the cooling condition and the exit condition are all determined by the temperature difference between the target temperature of the battery and the actual temperature of the battery.

Specifically, the heating conditions are: judging whether the temperature difference is larger than a first starting threshold value or not;

The refrigeration conditions are as follows: judging whether the temperature difference is smaller than a second starting threshold value;

the heating exit conditions are as follows: the temperature difference is less than a first ending threshold;

the refrigeration exit conditions are as follows: the temperature difference is greater than the second end threshold.

Specifically, the target temperature, the first start threshold, the first end threshold, the second start threshold and the second end threshold are all determined according to the battery model and the temperature corresponding to the highest power of the battery in charge and discharge.

The embodiment has the advantages that the cooling liquid is judged to be started or stopped to be regulated according to the difference value between the target temperature of the battery and the actual temperature of the battery, compared with the mode of judging only through the actual temperature of the battery, the cooling liquid regulating speed can be changed according to the difference value, and the cooling liquid regulating efficiency is improved.

Further, the battery operation mode includes: a parking discharge heating mode, a driving discharge heating mode, a parking discharge cooling mode, and a driving discharge cooling mode.

The embodiment has the advantages that compared with the existing battery operation mode, the method has the advantages that the influence of strong wind on a battery temperature zone is considered in the driving discharging heating mode and the driving discharging cooling mode, the adjusting strength of cooling liquid is optimized, and the temperature control failure caused by strong wind is avoided.

Specifically, the specific method for determining the specific initialization value of the PID control parameter by the battery operation mode is as follows:

firstly, determining an initialization proportion coefficient, an initialization integral time and an initialization differential time of a parking discharge heating mode and a parking discharge cooling mode;

secondly, on the basis of the initialization proportional coefficient, the initialization integral time and the initialization differential time determined by the parking discharge heating mode, correcting to obtain the initialization proportional coefficient, the initialization integral time and the initialization differential time of the driving discharge heating mode;

and on the basis of the initialization proportional coefficient, the initialization integral time and the initialization differential time determined by the parking discharge cooling mode, correcting to obtain the initialization proportional coefficient, the initialization integral time and the initialization differential time of the driving discharge cooling mode.

The embodiment has the advantages that the PID initialization control parameters of the parking discharge heating mode and the parking discharge cooling mode are used as the PID initialization parameters for calibrating typical working conditions, the PID initialization parameters in the other modes are simply verified after being preset according to theory, and the calibration workload is greatly reduced. Because of the PID closed-loop regulation characteristic, the proportional coefficient can continuously integrate and correct the final thermal management flow and power when the temperature difference exists, therefore, PID control parameters under different environment temperatures and different wind speeds do not need to be distinguished, the flow and the power can be lifted up when the temperature cannot be changed continuously, and the problem that the calibration working condition of the original method is not suitable for thermal management temperature control failure caused by the actual working condition is avoided.

Specifically, the parking discharge heating mode is a battery operation mode when the parking discharge heating mode is parked to be constant in temperature under the preset environment temperature and the starting battery is the battery heating;

the parking discharge cooling mode is a battery operation mode in which the battery is started to refrigerate under the condition that the temperature is constant when the battery is parked at the preset ambient temperature.

Further, the method for determining the initialization proportionality coefficient, the initialization integral time and the initialization differential time of the parking discharge heating mode and the parking discharge cooling mode comprises the following steps:

s1, determining a PID sampling period, wherein the PID sampling period is larger than an execution period;

s2, adjusting the proportion coefficient until the deviation generates critical oscillation;

s3, adjusting the integration time to enable the deviation to keep a preset steady-state error and oscillation time;

and S4, gradually increasing the differential time until the deviation reaches a preset target.

Specifically, the initialization PID parameter of the drive discharge heating mode > the initialization PID parameter of the parking discharge heating mode.

The initialization PID parameter of the driving discharging cooling mode > the initialization PID parameter of the parking discharging cooling mode.

The embodiment has the advantages that through a plurality of experiments and deductions, the influence of strong wind on battery temperature control under different temperatures and the influence of long-time parking on battery temperature control are compared, and based on the conclusion, the magnitude relation of the initial PID parameters under the two conditions is obtained, so that the efficiency and the effect of battery temperature control are improved.

Further, the battery operation mode further includes: a slow charge heating mode, a fast charge heating mode, a slow charge cooling mode, and a fast charge cooling mode.

Specifically, the initializing PID parameter of the driving discharging heating mode > the initializing PID parameter of the parking discharging heating mode = the initializing PID parameter of the slow charging heating mode > the initializing PID parameter of the fast charging heating mode;

the initialization PID parameter of the fast charge cooling mode > the initialization PID parameter of the driving discharge cooling mode > the initialization PID parameter of the parking discharge cooling mode = the initialization PID parameter of the slow charge cooling mode.

In another aspect, the present invention provides a battery temperature control apparatus comprising: the device comprises a battery temperature acquisition module, a cooling liquid adjusting module and a parameter initializing module;

the battery temperature acquisition module acquires the actual temperature of a battery;

the cooling liquid adjusting module is used for adjusting the temperature of cooling liquid entering the battery by adopting a PID closed-loop control algorithm according to the actual temperature of the battery so as to enable the cooling liquid to exchange heat with the battery;

and the parameter initialization module initializes control parameters of the PID closed-loop control algorithm, and the specific initialization value of the PID control parameters is determined by the current battery operation mode.

Further, the intelligent control system also comprises a control intervention judging module for judging whether the battery is at high voltage, if so, judging whether the actual temperature of the battery reaches a heating condition or a refrigerating condition, and if so, sending a working instruction to the cooling liquid regulating module.

Specifically, the cooling liquid adjusting module is used for controlling the entering temperature of the cooling liquid by adjusting the working power of the thermal management controller.

Further, the cooling liquid adjusting module controls the entering flow of the cooling liquid by adjusting the working power of the water pump.

Further, the device also comprises a control exit judging module for judging whether the current actual temperature of the battery reaches an exit condition, and if the current actual temperature of the battery reaches the exit condition, a stop instruction is sent to the cooling liquid adjusting module.

Further, the parameter initialization module divides the battery operation mode into: a parking discharge heating mode, a driving discharge heating mode, a parking discharge cooling mode, and a driving discharge cooling mode.

Specifically, the parameter initialization module initializes control parameters of the PID closed-loop control algorithm, and the specific method is as follows:

Specifically, the initialization PID parameter of the driving discharge heating mode > the initialization PID parameter of the parking discharge heating mode;

In another aspect, the present invention provides a storage medium storing a plurality of instructions adapted to be loaded by a processor to perform the above battery temperature control method.

In another aspect, the present invention provides a BMS battery system including the above battery temperature control device; and/or the storage medium described above.

It should be noted that, the terms "first", "second", and the like are used herein merely to describe each component in the technical solution, and do not constitute a limitation on the technical solution, and are not to be construed as indicating or implying importance of the corresponding component; elements with "first", "second" and the like mean that in the corresponding technical solution, the element includes at least one.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the technical effects, technical features and objects of the present invention will be further understood, and the present invention will be described in detail below with reference to the accompanying drawings, which form a necessary part of the specification, and together with the embodiments of the present invention serve to illustrate the technical solution of the present invention, but not to limit the present invention.

Like reference numerals in the drawings denote like parts, in particular:

fig. 1 is a schematic diagram of a general flow of a battery temperature control method.

Fig. 2 is a schematic flow chart of example 1.

Fig. 3 is a schematic structural diagram of embodiment 3.

Fig. 4 is a schematic diagram of the relationship between the battery charge and discharge peak power and the battery temperature.

Fig. 5 is a schematic diagram of the operation principle of the battery thermal management system.

FIG. 6 is a schematic diagram of a temperature change process during heating in a conventional thermal management system.

FIG. 7 is a schematic diagram showing the temperature change process of the conventional heat management system during cooling.

FIG. 8 is a schematic diagram of temperature change at the time of failure of the conventional thermal management system.

Fig. 9 is a schematic diagram showing the battery temperature change process under the control of example 1.

Fig. 10 is a schematic diagram of the PID closed-loop control flow of the thermal management controller and the water pump in example 1.

Wherein:

100. a battery temperature acquisition step;

110. the actual temperature of the battery;

120. a battery target temperature;

200. a control intervention judging step;

300. a step of adjusting the cooling liquid;

310. thermal management controller operating power;

320. the working power of the water pump;

350. initializing parameters;

360. PID control parameters;

400. a control exit judging step;

1000. a battery temperature control device;

1100. a battery temperature acquisition module;

1200. a control intervention judging module;

1300. a cooling liquid adjusting module;

1350. a parameter initialization module;

1400. and controlling the exit judging module.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. Of course, the following specific examples are set forth only to illustrate the technical solution of the present invention, and are not intended to limit the present invention. Furthermore, the parts expressed in the examples or drawings are merely illustrative of the relevant parts of the present invention, and not all of the present invention.

Example 1:

a battery temperature control method, as shown in fig. 1 and 2, includes: a battery temperature acquisition step 100, a coolant adjustment step 300, a parameter initialization step 350, a control intervention judgment step 200, and a control exit judgment step 400;

Firstly judging whether the battery is at high voltage or not, if the battery is not at high voltage, stopping temperature control, and if the battery is at high voltage, performing subsequent steps; in this embodiment, the determination of whether the battery is at high voltage may be performed before the battery temperature acquisition step 100, and the battery temperature may be acquired after the determination of the high voltage; the high voltage judgment can also be implemented by collecting the actual battery temperature 110 in real time after the battery temperature collection step 100, and judging whether the actual battery temperature 110 reaches the heating condition or the refrigerating condition according to the actual battery temperature 110 after the battery is high-voltage.

S1, a battery temperature acquisition step 100:

the actual battery temperature 110 is acquired or received or scanned in real time.

This step may be provided after the control intervention decision step 200, and the control intervention decision step 200 decides whether to collect the actual battery temperature 110.

S2, a control intervention judging step 200:

judging whether the actual battery temperature 110 reaches the heating condition or the cooling condition, if the actual battery temperature 110 reaches the heating condition or the cooling condition, starting the cooling liquid adjusting step 300, otherwise, ending the temperature control.

Further, the heating and cooling conditions are determined by the temperature difference between the battery target temperature 120 and the battery actual temperature 110. Of course, the temperature difference may also be the difference between the actual battery temperature 110 and the target battery temperature 120.

Specifically, the heating conditions are: judging whether the temperature difference is larger than a first starting threshold value or not; the refrigeration conditions are as follows: it is determined whether the temperature difference is less than a second onset threshold. Of course, when the definition of the temperature difference changes, the temperature difference changes correspondingly to the judgment standards of the first start threshold value and the second start threshold value.

In this embodiment, the first start threshold is 10 degrees and the second start threshold is-10 degrees. If the temperature is more than 10 ℃, the actual temperature 110 of the battery is considered to be lower, and the cooling liquid needs to be heated; if the temperature is less than-10 degrees, the actual temperature 110 of the battery is considered to be higher, and the cooling liquid is required to be cooled.

Further, the target temperature, the first starting threshold and the second starting threshold are all determined according to the battery model and the temperature corresponding to the highest power of the battery in charge and discharge. Of course, it may be determined according to the use environment or other factors.

In the embodiment, the temperature average value of the battery with highest charge and discharge power under different electric quantity is determined according to the battery characteristics and is used as the target temperature; the first start threshold and the second start threshold are obtained empirically or experimentally for different batteries.

S3, a cooling liquid adjusting step 300 and a parameter initializing step 350:

the coolant adjustment step 300 adjusts the temperature of the coolant entering the battery using a PID closed loop control algorithm based on the actual battery temperature 110, allowing the coolant to exchange heat with the battery.

Specifically, the PID closed loop control algorithm controls the inlet temperature of the coolant by adjusting the thermal management controller operating power 310. Of course, the PID closed loop control algorithm can also control the inlet temperature of the coolant by adjusting the operating time of the thermal management controller.

Further, the PID closed loop control algorithm also controls the incoming flow of coolant by adjusting the water pump operating power 320, as shown in FIG. 10. Of course, the thermal management controller may be adjusted only, with the water pump providing a constant flow of coolant; the percentage of the actual operating power of the water pump to the full power may also be synchronized with the percentage of the actual operating power of the thermal management controller to the full power.

A parameter initialization step 350, initializing control parameters of the PID closed-loop control algorithm, wherein the specific initialization value of the PID control parameters 360 is determined by the current battery operation mode.

Specifically, the battery operation modes include: a slow charge heating mode, a fast charge heating mode, a park discharge heating mode, a drive discharge heating mode, a slow charge cooling mode, a fast charge cooling mode, a park discharge cooling mode, and a drive discharge cooling mode. Of course, a new battery operation mode may be designed according to the actual use environment and use conditions.

Further, the parking discharge heating mode is a battery operation mode when the parking discharge heating mode is parked to be constant in temperature under the preset environment temperature and the starting battery is the battery heating; the parking discharge cooling mode is a battery operation mode in which the battery is started to refrigerate under the condition that the temperature is constant when the battery is parked at the preset ambient temperature.

In the embodiment, the preset ambient temperature is 35 ℃ when heating and-20 ℃ when cooling; of course, the preset ambient temperature can also be adjusted according to most ambient temperatures of the use area.

Specifically, a specific method for determining the specific initialization value of the PID control parameter 360 from the battery operating mode is:

secondly, on the basis of the initialization proportional coefficient, the initialization integral time and the initialization differential time determined by the parking discharge heating mode, correcting to obtain the initialization proportional coefficient, the initialization integral time and the initialization differential time of the slow charge heating mode, the fast charge heating mode and the driving discharge heating mode;

and on the basis of the initialization proportional coefficient, the initialization integral time and the initialization differential time determined by the parking discharge cooling mode, correcting to obtain the initialization proportional coefficient, the initialization integral time and the initialization differential time of the slow charge cooling mode, the fast charge cooling mode and the driving discharge cooling mode.

In this embodiment, the PID initialization control parameters may include only an initialization scale factor, may include an initialization scale factor and an initialization integration time, and may include an initialization scale factor, an initialization integration time, and an initialization differentiation time, and the specific control parameters are selected according to the result of adjusting the actual battery temperature 110.

1) Determining a PID sampling period, wherein the PID sampling period is larger than the execution period;

2) Adjusting the proportionality coefficient until the deviation has critical oscillation;

3) Adjusting the integration time to enable the deviation to keep a preset steady-state error and oscillation time;

4) The differential time is gradually increased until the deviation reaches a preset target.

In this embodiment, the critical oscillation method is used to determine the initialization proportionality coefficients, the initialization integration time and the initialization differential time of the parking discharge heating mode and the parking discharge cooling mode, and of course, other methods may be used to determine the initialization proportionality coefficients, the initialization integration time and the initialization differential time of the parking discharge heating mode and the parking discharge cooling mode.

Specifically, the initializing PID parameter of the driving discharging heating mode > the initializing PID parameter of the parking discharging heating mode = the initializing PID parameter of the slow charging heating mode > the initializing PID parameter of the fast charging heating mode; the initialization PID parameter of the fast charge cooling mode > the initialization PID parameter of the driving discharge cooling mode > the initialization PID parameter of the parking discharge cooling mode = the initialization PID parameter of the slow charge cooling mode.

In this embodiment, for four heating modes, the driving current is generally larger than the parking current, the battery pack generates slightly more heat, but the effect of cooling the battery by the head-on wind at low temperature has a larger influence on the temperature, and in order to raise the dynamic performance of the driving as soon as possible, the initialization PID parameter is required to be larger than the parking. When the vehicle is slowly charged and heated, the vehicle is in a parking working condition, and the magnitude of the current is close to the magnitude of the parking discharge, so that the vehicle can be initialized to be a parameter of the parking discharge. When the battery pack is charged and heated quickly, the charging current is far greater than that of the battery pack which is charged slowly, so that the initialized PID parameters can be slightly smaller. In addition, when heating, if the temperature difference is smaller than 0, the battery temperature exceeds the target temperature, and the parameter can be marked as a negative value at the moment, so that the flow and the heating power are cleared as soon as possible, and the energy waste is prevented.

The initialized scaling coefficients for the four heating modes are shown in the following table:

mode\temperature difference

-40

-20

-15

-10

-5

0

5

10

15

20

40

60

Parking discharge heating mode

-100％

-50％

-40％

-20％

-10％

10％

30％

40％

60％

80％

100％

Driving discharge heating mode

-100％

-50％

-40％

-20％

-10％

25％

40％

60％

80％

100％

Slow charge heating mode

-100％

-50％

-40％

-20％

-10％

10％

30％

40％

60％

80％

100％

Quick charge heating mode

-100％

-50％

-40％

-20％

-10％

5％

20％

30％

50％

70％

100％

In this embodiment, for four cooling modes, the driving current is generally larger than the parking current, the battery pack generates slightly more heat, the cooling effect of the battery is lower when the battery is subjected to the windward at high temperature, and the preset parameter is required to be larger than the parking in order to raise the dynamic performance of the driving as soon as possible. During slow charge, the parking working condition is adopted, and the current magnitude is close to the magnitude of the parking discharge, so that the parking discharge parameter can be preset. During fast charging, the charging current is far greater than that of slow charging, so that the battery pack generates more heat, the preset parameter is required to be greater than that of slow charging, the working condition is parking, and the cooling effect of windward is avoided, so that the parameter is also required to be greater than that of travelling crane. In addition, when cooling, if the temperature difference is greater than 0, the battery temperature is lower than the target temperature, and the parameter can be marked as a negative value at the moment, so that the flow and the heating power are cleared as soon as possible, and the energy waste is prevented.

The initialized scaling coefficients for the four modes of cooling are shown in the following table:

mode\temperature difference

-40

-20

-15

-10

-5

0

5

10

15

20

40

60

Parking discharge cooling mode

100％

70％

60％

40％

35％

15％

-10％

-50％

-70％

-100％

Driving discharge cooling mode

100％

80％

50％

60％

40％

25％

-10％

-50％

-70％

-100％

Slow charge cooling mode

100％

70％

60％

40％

35％

15％

-10％

-50％

-70％

-100％

Quick charge cooling mode

100％

90％

80％

50％

30％

-10％

-50％

-70％

-100％

When the ambient temperature changes greatly, the magnitude relation of the initialized PID parameters of different modes may change correspondingly. After initializing PID control parameters, verifying and fine-tuning are performed under each working condition. As shown in FIG. 9, due to the characteristics of PID closed-loop regulation, even if the PID closed-loop regulation is unsuitable for presetting, the initialization proportional coefficient can continuously integrate and correct the final heat management flow and power according to the temperature difference, so that the flow and power can be ensured to be changed by initializing the integral of the proportional coefficient when the temperature cannot be changed continuously, and the problem of heat management temperature control failure caused by inapplicability of the original method calibration working condition to the actual working condition is avoided.

S4, control exits the judging step 400:

it is determined whether the current battery actual temperature 110 reaches the exit condition, and if so, the coolant adjustment step 300 is stopped.

Further, the exit condition is determined by the temperature difference between the battery target temperature 120 and the battery actual temperature 110.

Specifically, the exit conditions include a heating exit condition and a cooling exit condition; the heating exit conditions are as follows: the temperature difference is less than a first ending threshold; the refrigeration exit conditions are as follows: the temperature difference is greater than the second end threshold.

Further, the first ending threshold and the second ending threshold are determined according to the battery model and the temperature corresponding to the highest power of the battery in charge and discharge.

In this embodiment, the first end threshold is-5 degrees and the second end threshold is 5 degrees. Of course, the first end threshold and the second end threshold may also be adjusted as desired.

Example 2:

alternatively, in the control intervention judging step 200, the heating condition is: whether the battery actual temperature 110 is less than a first starting threshold; the refrigeration conditions are as follows: whether the battery actual temperature 110 is greater than a second start threshold;

as an alternative means, in the control exit judging step 400, the exit conditions include a heating exit condition and a cooling exit condition; the heating exit conditions are as follows: the actual temperature is greater than a first end threshold; the refrigeration exit conditions are as follows: the actual temperature is less than the second end threshold.

Further, the first starting threshold, the first ending threshold, the second starting threshold and the second ending threshold are all determined according to the battery model and the temperature corresponding to the highest power of the battery charge and discharge.

Example 3:

a battery temperature control apparatus 1000, as shown in fig. 3, includes: a battery temperature acquisition module 1100, a coolant adjustment module 1300, and a parameter initialization module 1350;

The battery temperature acquisition module 1100 acquires the actual battery temperature 110;

the cooling liquid adjusting module 1300 adjusts the temperature of the cooling liquid entering the battery by adopting a PID closed-loop control algorithm according to the actual temperature 110 of the battery, so that the cooling liquid exchanges heat with the battery;

the parameter initialization module 1350 initializes the control parameters of the PID closed loop control algorithm, and the specific initialization values of the PID control parameters 360 are determined by the current battery operating mode.

In this embodiment, the battery temperature acquisition module 1100 may be a sensor module disposed on the battery, or may be a data acquisition circuit that may receive battery temperature data; the coolant adjustment module 1300 may be a control circuit locally disposed in an automobile, or may be a mobile terminal or a cloud server, and control the water pump and the thermal management controller through wireless communication; the parameter initialization module 1350 may be a separate circuit from the coolant adjustment module 1300 or may be integrated with the coolant adjustment module 1300. The output end of the battery temperature acquisition module 1100 is electrically connected with the receiving end of the coolant adjustment module 1300, and the output end of the parameter initialization module 1350 is electrically connected with the receiving end of the coolant adjustment module 1300.

Further, the control intervention judging module 1200 is further included to judge whether the battery is at high voltage, if so, judge whether the actual battery temperature 110 reaches the heating condition or the cooling condition, and if so, send a working instruction to the coolant adjusting module 1300.

In this embodiment, the command output end of the control intervention judging module 1200 may be electrically connected to the receiving end of the coolant adjusting module 1300, or may be electrically connected to both the receiving end of the coolant adjusting module 1300 and the command receiving end of the battery temperature collecting module 1100.

Specifically, the coolant conditioning module 1300 controls the incoming temperature of the coolant by adjusting the thermal management controller operating power 310.

Further, the coolant adjustment module 1300 controls the intake flow of coolant by adjusting the water pump operating power 320.

In this embodiment, the command output of the coolant conditioning module 1300 may be electrically connected to the command input of the thermal management controller, or may be electrically connected to both the thermal management controller and the command input of the water pump.

Further, the control exit judging module 1400 is further included to judge whether the current actual battery temperature 110 reaches the exit condition, and if the exit condition is reached, a stop command is sent to the coolant adjusting module 1300.

In this embodiment, the command output end of the control exit judging module 1400 is electrically connected with the command input end of the coolant adjusting module 1300; the control exit judging module 1400 may be provided locally in the automobile or may be provided on a mobile terminal or a cloud server.

Specifically, the parameter initialization module 1350 divides the battery operating modes into: a slow charge heating mode, a fast charge heating mode, a park discharge heating mode, a drive discharge heating mode, a slow charge cooling mode, a fast charge cooling mode, a park discharge cooling mode, and a drive discharge cooling mode.

Further, the parameter initialization module 1350 initializes control parameters of the PID closed-loop control algorithm, which specifically includes:

Specifically, the initialization PID parameter of the running discharge heating mode > the initialization PID parameter of the parking discharge heating mode = the initialization PID parameter of the slow charge heating mode > the initialization PID parameter of the fast charge heating mode.

Specifically, the initialization PID parameter of the fast charge cooling mode > the initialization PID parameter of the drive discharge cooling mode > the initialization PID parameter of the park discharge cooling mode = the initialization PID parameter of the slow charge cooling mode.

It should be noted that the foregoing examples are merely for clearly illustrating the technical solution of the present invention, and those skilled in the art will understand that the embodiments of the present invention are not limited to the foregoing, and that obvious changes, substitutions or alterations can be made based on the foregoing without departing from the scope covered by the technical solution of the present invention; other embodiments will fall within the scope of the invention without departing from the inventive concept.

Claims

1. A battery temperature control method, characterized by comprising: a battery temperature acquisition step, a cooling liquid adjustment step and a parameter initialization step; wherein,,

the battery temperature acquisition step is used for acquiring the actual temperature of the battery;

the step of regulating the cooling liquid, namely regulating the temperature of the cooling liquid entering the battery by adopting a PID closed-loop control algorithm according to the actual temperature of the battery, so that the cooling liquid exchanges heat with the battery;

and initializing the parameters, namely initializing control parameters of a PID closed-loop control algorithm, wherein the specific initialization value of the PID control parameters is determined by the current battery operation mode.

2. The battery temperature control method according to claim 1, further comprising a control intervention judging step that is located before the coolant adjusting step;

the control intervention judging step is that firstly judging whether the battery is at high voltage or not, if the battery is not at high voltage, terminating the temperature control;

if the battery is at high voltage, judging whether the actual temperature of the battery reaches a heating condition or a refrigerating condition, if the actual temperature of the battery reaches the heating condition or the refrigerating condition, starting the cooling liquid adjusting step, otherwise, stopping temperature control.

3. The battery temperature control method of claim 1, wherein the PID closed loop control algorithm controls the inlet temperature of the coolant by adjusting the operating power of the thermal management controller.

4. The battery temperature control method of claim 3, wherein the PID closed loop control algorithm further controls the intake flow of coolant by adjusting the operating power of the water pump.

5. The battery temperature control method according to claim 1, further comprising a control exit judging step of judging whether or not the current actual temperature of the battery reaches an exit condition, and if the exit condition is reached, stopping the coolant adjusting step.

6. The battery temperature control method according to claim 5, wherein the heating condition is: whether the actual temperature of the battery is less than a first starting threshold;

the refrigerating conditions are as follows: whether the actual temperature of the battery is greater than a second start threshold;

the refrigerating exiting condition is as follows: the actual temperature is less than the second end threshold.

7. The battery temperature control method according to claim 6, wherein the first start threshold, the first end threshold, the second start threshold, and the second end threshold are each determined according to a battery model and a temperature corresponding to a highest power of the battery charge and discharge.

8. The battery temperature control method according to claim 5, wherein the heating condition, the cooling condition, and the exit condition are each determined by a temperature difference between a battery target temperature and an actual temperature of the battery.

9. The battery temperature control method according to claim 8, wherein the heating condition is: judging whether the temperature difference is larger than a first starting threshold value or not;

the refrigerating conditions are as follows: judging whether the temperature difference is smaller than a second starting threshold value;

the refrigerating exiting condition is as follows: the temperature difference is greater than the second end threshold.

10. The battery temperature control method according to claim 9, wherein the target temperature, the first start threshold, the first end threshold, the second start threshold, and the second end threshold are determined according to a battery model and a temperature corresponding to a highest power of charge and discharge of the battery.

11. The battery temperature control method according to claim 1, wherein the battery operation mode includes: a parking discharge heating mode, a driving discharge heating mode, a parking discharge cooling mode, and a driving discharge cooling mode.

12. The battery temperature control method according to claim 11, wherein the specific method of determining the specific initialization value of the PID control parameter from the battery operation mode is:

firstly, determining an initialization proportionality coefficient, an initialization integral time and an initialization differential time of the parking discharge heating mode and the parking discharge cooling mode;

secondly, on the basis of the initialization proportional coefficient, the initialization integral time and the initialization differential time determined by the parking discharge heating mode, correcting and obtaining the initialization proportional coefficient, the initialization integral time and the initialization differential time of the driving discharge heating mode;

and correcting and obtaining the initialization proportional coefficient, the initialization integral time and the initialization differential time of the driving discharge cooling mode on the basis of the initialization proportional coefficient, the initialization integral time and the initialization differential time determined by the parking discharge cooling mode.

13. The battery temperature control method according to claim 12, wherein the parking discharge heating mode is a battery operation mode when parking to a constant temperature at a preset ambient temperature and starting the battery to heat the battery;

14. The battery temperature control method according to claim 13, wherein the initialization proportionality coefficient, the initialization integration time and the initialization differentiation time of the parking discharge heating mode and the parking discharge cooling mode are determined as follows:

15. The battery temperature control method according to claim 12, wherein an initialization PID parameter of the charge-discharge heating mode > an initialization PID parameter of the parking-discharge heating mode.

And the initialization PID parameter of the driving discharge cooling mode is greater than the initialization PID parameter of the parking discharge cooling mode.

16. The battery temperature control method of claim 12, wherein the battery operating mode further comprises: a slow charge heating mode, a fast charge heating mode, a slow charge cooling mode, and a fast charge cooling mode.

17. The battery temperature control method according to claim 16, wherein an initialization PID parameter of the charge-discharge heating mode > an initialization PID parameter of the parking-discharge heating mode = an initialization PID parameter of the slow charge heating mode > an initialization PID parameter of the fast charge heating mode;

and the initialization PID parameter of the fast charge cooling mode > the initialization PID parameter of the driving discharge cooling mode > the initialization PID parameter of the parking discharge cooling mode = the initialization PID parameter of the slow charge cooling mode.

18. A battery temperature control apparatus, comprising: the device comprises a battery temperature acquisition module, a cooling liquid adjusting module and a parameter initializing module;

the battery temperature acquisition module acquires the actual temperature of the battery;

19. The battery temperature control device of claim 18, further comprising a control intervention judging module for judging whether the battery is at a high voltage, if so, judging whether the actual temperature of the battery reaches a heating condition or a cooling condition, and if so, sending a working instruction to the coolant regulating module.

20. The battery temperature control device of claim 18, wherein the coolant adjustment module controls the inlet temperature of the coolant by adjusting the operating power of the thermal management controller.

21. The battery temperature control device of claim 20, wherein the coolant adjustment module controls the inflow of coolant by adjusting the operating power of the water pump.

22. The battery temperature control device of claim 18, further comprising a control exit determination module that determines whether a current actual temperature of the battery has reached an exit condition, and if the exit condition is reached, issues a stop command to the coolant adjustment module.

23. The battery temperature control device of claim 18, wherein the parameter initialization module divides the battery operating mode into: a parking discharge heating mode, a driving discharge heating mode, a parking discharge cooling mode, and a driving discharge cooling mode.

24. The battery temperature control device of claim 23, wherein the parameter initialization module initializes control parameters of a PID closed-loop control algorithm by:

25. The battery temperature control device according to claim 24, wherein an initialization PID parameter of the charge-discharge heating mode > an initialization PID parameter of the parking-discharge heating mode;

26. A storage medium storing instructions adapted to be loaded by a processor to perform the battery temperature control method of any one of claims 1 to 17.

27. A BMS battery system comprising the battery temperature control device according to any one of claims 18 to 25; and/or a storage medium according to claim 26.