Automobile battery heating and heat preservation control method based on negative feedback regulation

Abstract

The invention relates to an automobile battery heating and heat preservation control method based on negative feedback regulation. The method comprises the steps that the environment temperature, the storage battery temperature, the power battery temperature, the liquid domain temperature and the automobile control state are obtained; step 2, judging whether the storage battery temperature, the power battery temperature and the liquid domain temperature are lower than a preset limit temperature, if so, executing step 3, and otherwise, executing step 6; 3, the liquid domain is heated, the current temperature is fed back, whether the current temperature reaches the preset temperature or not is judged, if yes, the step 2 is executed, and if not, the step 4 is executed; 4, feeding back the required heating power by combining the current temperature with the heating transfer function; 5, the heating power is adjusted according to the needed heating power and the power transfer function, and the step 3 is executed; and 6, stopping heating the liquid region to enable the automobile to normally run, and executing the step 1. Liquid domain heating is controlled based on a negative feedback regulation principle, so that the battery can be effectively ensured to be at a proper working temperature in time, and the energy consumption is low.

Description

Technical Field

[0001] The invention relates to a heating and heat preservation technology for automobile batteries, and in particular to a control method for heating and heat preservation of automobile batteries based on negative feedback regulation. Background Art

[0002] With the development of new energy vehicles, pure electric vehicles and hybrid vehicles with batteries as the main power source have been widely put into use. However, the development of electric vehicles at this stage is largely limited by factors such as battery stability, safety and service life. The most prominent one is the impact of battery operating temperature, especially when the car is in a low temperature environment (-10℃ and below), the internal activity of the battery is reduced, causing the battery to be in an unhealthy environment, causing irreversible damage to the battery, and thus accelerating battery aging; when the battery is running in an unhealthy state, it will reduce battery performance and fail to meet the expected performance requirements. After shutting down in a low temperature environment, the battery may cause the subsequent vehicle to be unable to start or high voltage in a low temperature state. At present, there are more common problems such as the inability to start the car in a low temperature environment, the shortened endurance of new energy vehicles in a low temperature environment, the reduced battery life, and the weak discharge capacity. In the era of new energy vehicles, the performance of the battery used to start the car is reduced. Due to the characteristics of the battery itself, low temperature is extremely unfriendly to the battery. The battery needs to be given a normal operating temperature to avoid the situation where the car cannot start.

[0003] In the prior art, there are usually two methods for heating batteries: charging heating and discharging heating. In the charging heating method, in order to avoid overvoltage of the battery, the power battery needs to be strictly restricted, and the restriction seriously restricts the flexibility and heating effect of the heating. In the discharging heating method, as the car is parked in a low-temperature environment, the battery pack may be completely discharged or even over-discharged, thereby affecting the performance and life of the battery pack. The above heating methods all have certain safety hazards, and the amount of charging and discharging cannot be effectively controlled in time, which easily leads to overcharging or over-discharging. Summary of the invention

[0004] The purpose of the present invention is to provide a control method for heating and heat preservation of automobile batteries based on negative feedback regulation, so as to solve the problem in the prior art that it is difficult for the battery to obtain a good heating and heat preservation effect when the automobile is driving or parked at low temperatures, resulting in battery aging and performance degradation.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A control method for heating and keeping warm of a car battery based on negative feedback regulation, comprising:

[0007] Step 1: Obtain the ambient temperature, battery temperature, power battery temperature, liquid temperature and vehicle control status;

[0008] Step 2: determine whether the battery temperature, the power battery temperature and the liquid temperature are lower than a preset limit temperature.

[0009] If yes, go to step 3, otherwise go to step 6;

[0010] Step 3: heat the liquid domain and feed back the current temperature to determine whether the current temperature reaches the preset temperature. If so, execute step 1; otherwise, execute step 4.

[0011] Step 4: Feedback the required heating power based on the current temperature combined with the heating transfer function;

[0012] Step 5: adjusting the heating power according to the required heating power combined with the power transfer function, and executing step 3;

[0013] Step 6: Stop heating the liquid region to allow the vehicle to operate normally, and execute step 1.

[0014] According to the above technical means, the present invention indirectly heats the storage battery and the power battery by heating the liquid domain, and when the heating temperature cannot reach the preset temperature, the currently required heating power can be continuously obtained through negative feedback regulation, thereby adjusting the heating power so that the heating temperature reaches the preset temperature, and the negative feedback regulation can continuously adjust the heating power so that the heating temperature is always maintained within the preset temperature range, so as to achieve the effect of both heating and keeping the battery warm. By regulating the heating power through negative feedback, not only can the energy loss caused by the system always heating at a higher power be effectively avoided, but also the entire heating and insulation process can be made stable and reliable.

[0015] Further, the vehicle control state is ON.

[0016] According to the above technical means, a judgment condition of a specific implementation mode of the present invention is limited to that the car is in a driving state.

[0017] Furthermore, the step one also includes determining whether the ambient temperature is lower than a preset temperature threshold, if so, executing step two, otherwise executing step six.

[0018] According to the above technical means, a judgment condition of a specific implementation mode of the present invention is defined, and this judgment condition is a prerequisite for whether to perform heating and heat preservation on the battery.

[0019] Further, the vehicle control state is OFF.

[0020] According to the above technical means, the judgment condition of another specific implementation mode of the present invention is defined as that the car is in a parking state.

[0021] Furthermore, the ambient temperature in step one is the weather forecast temperature of the current parking location of the car, and a temperature curve is fitted according to the weather forecast temperature to generate a temperature transfer function.

[0022] Furthermore, the weather forecast temperature is obtained through the vehicle-mounted central control unit.

[0023] According to the above technical means, the temperature transfer function of the future time period at the current position can be obtained, so that the battery heating and insulation control system of the present invention can predict the error trend between the current temperature and the preset temperature based on the temperature transfer function, thereby making predictive adjustments to the required heating power in advance, which can improve the response rate of the battery heating and insulation control system.

[0024] Furthermore, the step 2 also includes determining whether the minimum air temperature is lower than the preset limit temperature.

[0025] According to the above technical means, the judgment condition of another specific implementation mode of the present invention is defined. This judgment condition is one of the conditions for whether to perform heating and insulation on the battery. Using the minimum air temperature as the judgment condition can avoid the control system reading the weather information of the vehicle-mounted central control unit in real time, thereby further reducing energy loss.

[0026] Furthermore, the step four also includes combining the weather forecast temperature with the temperature transfer function to obtain the future temperature change rate, and combining the current temperature with the heating transfer function and the future temperature change rate to feedback the required heating power.

[0027] According to the above technical means, the required heating power in the future can be predicted based on the future temperature change trend and combined with the heating transfer function, thereby reducing the overshoot and increasing the stability of the battery heating and insulation control system.

[0028] Furthermore, steps one to six also include obtaining the remaining power of the power battery and determining whether the remaining power is lower than a preset power threshold. If so, the remaining power information is pushed to the user-side APP to remind the user to charge in time and stop heating, otherwise proceed to the next step.

[0029] According to the above technical means, it is possible to effectively avoid the situation where the battery power is too low due to heating and heat preservation of the battery, and eventually the battery is exhausted and breaks down.

[0030] Furthermore, the ambient temperature is acquired through a vehicle control system, the battery temperature is acquired through an intelligent battery sensor, the power battery temperature is acquired through a battery management system, and the liquid domain temperature is acquired by detecting the temperature of a heat-conducting liquid in a liquid domain heating device.

[0031] According to the above technical means, the method of obtaining the temperature of each parameter can be clarified.

[0032] Beneficial effects of the present invention:

[0033] (1) The present invention can continuously obtain the currently required heating power through negative feedback regulation, thereby adjusting the heating power so that the heating temperature reaches the preset temperature, and the negative feedback regulation can continuously adjust the heating power so that the heating temperature is always kept within the preset temperature range, so as to achieve the effect of both heating and keeping the battery warm. By regulating the heating power through negative feedback, not only can the energy loss caused by the system always heating with a higher power be effectively avoided, but also the entire heating and keeping warm process can be made stable and reliable;

[0034] (2) The present invention obtains the temperature transfer function of the future time period at the current position, thereby enabling the battery heating and heat preservation control system of the present invention to predict the error trend between the current temperature and the preset temperature based on the temperature transfer function, thereby making predictive adjustments to the required heating power in advance, thereby improving the response rate of the battery heating and heat preservation control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the method flow of the present invention;

[0036] Figure 2 It is a flow chart of negative feedback regulation control of vehicle heating and heat preservation in a specific embodiment of the present invention;

[0037] Figure 3 This is a flow chart of negative feedback regulation control of parking heating and heat preservation in a specific implementation manner of the present invention. DETAILED DESCRIPTION

[0038] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0039] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0040] This embodiment proposes a control method for heating and heat preservation of automobile batteries based on negative feedback regulation, including: step 1, obtaining ambient temperature, battery temperature, power battery temperature, liquid domain temperature and automobile control state; step 2, judging whether the battery temperature, power battery temperature and liquid domain temperature are lower than a preset limit temperature, if so, executing step 3, otherwise executing step 6; step 3, heating the liquid domain and feeding back the current temperature, judging whether the current temperature reaches the preset temperature, if so, executing step 1, otherwise executing step 4; step 4, feeding back the required heating power based on the current temperature combined with the heating transfer function;

[0041] Step 5: adjust the heating power according to the required heating power combined with the power transfer function, and execute step 3; Step 6: stop heating the liquid domain to allow the vehicle to run normally, and execute step 1.

[0042] Specifically, in a specific embodiment of the present invention, in a negative feedback closed-loop system, the unidirectional input is R(s), the unidirectional output is C(s), the error signal is E(s), the feedback signal is B(s), the forward channel transfer function is G(s), the feedback channel transfer function is H(s), and the open-loop transfer function of the closed-loop system is Then, under the action of input signal R(s) and interference signal D(s) = 0, the closed-loop transfer function of the system is: The output pull transformation is: Based on this principle, the liquid temperature T L , battery temperature T I , power battery temperature T B And the weather forecast temperature T F Substitute the open-loop transfer function G of the closed-loop system into K (s), the closed-loop negative feedback heating transfer function F(x), the negative feedback power transfer function F(y) and the negative feedback temperature transfer function F(z) can be obtained, and each transfer function has a constant C for calibration compensation. The value of the constant C changes with the type of the storage battery and power battery, the weight of the vehicle body and the atmospheric pressure, so that the battery heating and insulation control system of the present invention has a strong anti-interference ability and a smaller error.

[0043] In a specific implementation of the heating and heat preservation process of the present invention, the liquid domain heating device heats the liquid domain, the temperature detection sensor detects the liquid domain temperature and feeds back the current temperature of the liquid domain to the control system, and the control system calculates the difference between the current temperature of the liquid domain and the preset temperature in the system, thereby obtaining the deviation value E between the preset temperature SP and the current temperature PV of the liquid domain, and E=SP-PV. The control system determines whether the deviation value E is within the allowable error range. If so, it returns to step 1 to continue to obtain the current temperature and determine whether heating and heat preservation are required. If the deviation value exceeds the allowable error range, PID control can be performed on the deviation value, and the transfer function of PID is: Where K p is the proportionality coefficient, K I is the integration coefficient, K D is the differential coefficient, T t is the integral time constant, τ is the differential time constant, s is the current moment, and the heating transfer function in the negative feedback regulation is F(x). The control system calculates the required heating power as The control system feeds back the required heating power to the battery management system, which compares the required heating power with the current heating power to obtain the deviation between the two, and obtains the adjusted heating power in combination with the power transfer function F(y) in the negative feedback regulation, thereby driving the liquid domain heating controller to heat the liquid domain with the adjusted heating power, so that the control system continuously adjusts the power of the liquid domain heating device according to the feedback signal to keep the liquid domain temperature within the preset temperature range. Specifically, if the liquid domain temperature is too high, the feedback signal will increase, and the control system will reduce the heating power of the liquid domain heating device, thereby reducing the temperature. If the liquid domain temperature is too low, the feedback signal will decrease, and the control system will increase the heating power of the liquid domain heating device, thereby increasing the temperature. The control system continuously repeats the above steps to heat and keep the battery warm, and the automobile battery heating and heat preservation control method based on negative feedback regulation of the present invention will keep the temperature within the preset temperature range, thereby achieving the goal of temperature control. It should be noted that the above transfer function is not a specific function. The function can be deformed and transformed according to the specific actual use situation, and the parameters brought in can also be added and modified according to the actual application situation. The formula given in this embodiment is only a principle example. In order to facilitate the understanding of the technical solution of the present invention, in actual use, the deviation value between the preset temperature and the current temperature of the liquid domain can also be subjected to different control methods such as fuzzy control, neural network control, and fuzzy neural network control.

[0044] Specifically, see Figure 1, as a specific embodiment of the present invention, the car control state is ON. And the step one also includes judging whether the ambient temperature is lower than the preset temperature threshold. If so, execute step two, otherwise execute step six. In this specific embodiment, the car is in driving state, the control system obtains the external ambient temperature in real time, and judges whether the ambient temperature is lower than the preset temperature threshold. In this embodiment, the preset temperature threshold is set to -10°C. When it is judged that the ambient temperature is lower than -10°C, the control system can push information suggesting to turn on the driving heating function to the user. After obtaining the user's permission instruction, the next step of judgment and heating and heat preservation treatment of the battery can be carried out. The judgment process and the method of heating and heat preservation of the battery have been described in the above technical solution, which will not be repeated here. One of the conditions for stopping the cycle in this embodiment is that the liquid domain temperature received by the control system is within the preset temperature range, and the obtained ambient temperature is not lower than -10°C, then the cycle is stopped until the next time the ambient temperature is lower than -10°C and the cycle is started again.

[0045] See also Figure 2 As another specific embodiment of the present invention, the vehicle control state is OFF, and the ambient temperature in step 1 is the weather forecast temperature of the current parking position of the vehicle, a temperature curve is fitted according to the weather forecast temperature and a temperature transfer function is generated, and the weather forecast temperature is obtained through the vehicle-mounted central control unit. Step 2 also includes determining whether the minimum air temperature is lower than the preset limit temperature. Step 4 also includes obtaining the future temperature change rate by combining the weather forecast temperature with the temperature transfer function, and the current temperature is combined with the heating transfer function and the future temperature change rate to feedback the required heating power.

[0046] Specifically, in this specific implementation, the car is in a parked state, and the control system obtains the weather forecast temperature of the parking position through the on-board central control unit, and obtains the lowest temperature within 24 hours after the current time period, and the lowest temperature is lower than the preset limit temperature. The control system will fit the temperature curve according to the weather forecast temperature and generate a temperature transfer function F(z). Since the weather forecast will be updated at regular intervals, the control system will re-obtain the weather forecast temperature from the on-board central control unit at regular intervals and update the temperature transfer function F(z). The control system compares the obtained weather forecast temperature with the preset limit temperature. If the weather forecast temperature is lower than the preset limit temperature, and the battery temperature, power battery temperature and liquid domain temperature are all lower than the preset limit temperature, the control system can send a battery heating and insulation request to the user. After obtaining the user's permission instruction, the next step of judgment and battery heating and insulation treatment can be carried out. In this specific embodiment, on the basis of the above technical solution, the control system also needs to compare the current ambient temperature with the future weather forecast temperature, and predict the trend of the deviation between the current ambient temperature and the future weather forecast temperature, thereby making a predictive adjustment to the required heating power output by the control system. For example, the current ambient temperature is -12℃, the future weather forecast temperature is -7℃, the current temperature of the liquid domain is 10℃, the preset temperature is 25℃, and the liquid domain heating device heats the liquid domain with a certain heating power. When the current ambient temperature is -12℃, the weather is too cold, and the heat dissipation speed of the liquid domain is just equal to the heating speed under proportional control, the liquid domain temperature will remain at 20℃. At this time, the control system will accumulate temperature deviations, thereby increasing the heating power of the liquid domain heating device so that the liquid domain temperature can reach 25℃. However, when the current ambient temperature is -7℃, the weather is warmer than -12℃, and the heat dissipation speed of the liquid domain is lower, so the heating power required to heat the liquid domain temperature to 25℃ is less. If the heating power when the ambient temperature is -12℃ is still used, it will cause unnecessary energy consumption and cause instability of the heating and heat preservation control system. In the above description, the prediction and adjustment of the future weather forecast temperature is added to the circulation system of the output required heating power, which can make the error of the required heating power output by the control system smaller and the result more accurate, thereby reducing unnecessary energy consumption and further increasing the battery life. The method for further adjusting the required heating power has been described in the above technical solution and will not be repeated here.

[0047] In this embodiment, steps one to six also include obtaining the remaining power of the power battery and determining whether the remaining power is lower than a preset power threshold. If so, the remaining power information is pushed to the user-side APP to remind the user to charge in time and stop heating, otherwise proceed to the next step.

[0048] Specifically, the preset power threshold of this embodiment is preferably 15%. When the remaining power of the vehicle power battery is not higher than 15%, the user-side APP can remind the user to charge in time. In addition, the user-side APP can also be used to remind the user to turn on the battery heating and insulation. Specifically, when the vehicle is in a low temperature area and the battery heating and insulation function is not turned on, a message suggesting to turn on the battery heating and insulation function is pushed to the user. After obtaining the user's permission instruction, the command is fed back to the control system. It should be noted that the battery management system will determine whether the battery needs to be heated and whether it can be heated based on the current driving cycle estimated mileage, the current driving cycle estimated maximum required power, the current driving cycle estimated driving time sent by the vehicle remote communication terminal, and the remaining power and battery discharge power calculated by the battery management system. When heating is required and can be performed, a battery heating start instruction is sent.

[0049] In the above specific implementation manner, the ambient temperature is obtained through the vehicle control system, the battery temperature is obtained through the intelligent battery sensor, the power battery temperature is obtained through the battery management system, and the liquid domain temperature is obtained by detecting the temperature of the heat-conducting liquid in the liquid domain heating device.

[0050] Specifically, in order to better understand the technical solution of the present invention, the liquid domain heating device is described below. The liquid domain heating device has at least two liquid cooling plates, and the liquid cooling plates are arranged in parallel and spaced apart. A liquid cooling channel is opened inside the liquid cooling plate. A heating cavity is provided on the upper and lower sides of the liquid cooling plate. The heating belt is installed in the heating cavity so that the heat-conducting liquid in the liquid cooling plate is heated from the upper and lower ends of the liquid cooling plate. The battery module includes a battery cell and a module shell, the liquid domain heating device is installed in the module shell, and the battery cell is clamped between two adjacent liquid cooling plates. Based on this liquid domain heating device, the storage battery and the power battery can be externally heated so that the storage battery and the power battery work at a suitable temperature. It should be noted that the above structural description of the liquid domain heating device is only for a further understanding of the technical solution of the present invention, and does not constitute a specific limitation of the present invention.

[0051] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A control method for heating and keeping warm of automobile batteries based on negative feedback regulation, characterized in that: include: Step 1: Obtain the ambient temperature, battery temperature, power battery temperature, liquid temperature and vehicle control status; Step 2: determine whether the battery temperature, the power battery temperature and the liquid temperature are lower than a preset limit temperature; if so, proceed to step 3; otherwise, proceed to step 6; Step 3: heat the liquid domain and feed back the current temperature, and determine whether the current temperature is within a preset temperature range. If so, execute step 1, otherwise execute step 4; Step 4: Feedback the required heating power based on the current temperature combined with the heating transfer function; Step 5: adjusting the heating power according to the required heating power combined with the power transfer function, and executing step 3; Step 6: Stop heating the liquid region to allow the vehicle to operate normally, and execute step 1.

2. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to claim 1 is characterized in that: The vehicle control state is ON.

3. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to claim 2 is characterized in that: The step one also includes determining whether the ambient temperature is lower than a preset temperature threshold, if so, executing step two, otherwise executing step six.

4. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to claim 1, characterized in that: The vehicle control state is OFF.

5. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to claim 4 is characterized in that: The ambient temperature in step 1 is the weather forecast temperature of the current parking location of the car, and a temperature curve is fitted according to the weather forecast temperature to generate a temperature transfer function.

6. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to claim 5 is characterized in that: The weather forecast temperature is obtained through the vehicle-mounted central control unit.

7. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to claim 5, characterized in that: The step 2 also includes determining whether the minimum air temperature is lower than the preset limit temperature.

8. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to claim 7 is characterized in that: The step four also includes combining the weather forecast temperature with the temperature transfer function to obtain the future temperature change rate, and combining the current temperature with the heating transfer function and the future temperature change rate to feed back the required heating power.

9. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to any one of claims 4 to 8, characterized in that: The steps one to six also include obtaining the remaining power of the power battery and determining whether the remaining power is lower than a preset power threshold. If so, the remaining power information is pushed to the user-side APP to remind the user to charge in time and stop heating, otherwise proceed to the next step.

10. The control method for heating and keeping warm of automobile batteries based on negative feedback regulation according to any one of claims 1 to 8, characterized in that: The ambient temperature is obtained through the vehicle control system, the battery temperature is obtained through the intelligent battery sensor, the power battery temperature is obtained through the battery management system, and the liquid domain temperature is obtained by detecting the temperature of the heat-conducting liquid in the liquid domain heating device.

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