Vehicle duty time calculation method based on lithium battery SOC parameters

Abstract

The invention belongs to the technical field of vehicle energy management control, and particularly relates to a vehicle duty time calculation method based on lithium battery SOC parameters. According to the method, starting meshing voltage and current under different temperature conditions are tested, starting required energy under different temperature conditions is calculated, the SOC, voltage and current parameters of the lithium battery are detected in real time, and through formula calculation, the time that the current battery of a passenger can provide heating duty is provided according to a certain transmission period, so that the temperature of the passenger can be raised. Suggestions for guaranteeing the work of passengers are given in time, and reliable achievement of starting and guarding functions of the vehicle is guaranteed; over-discharge of the lithium battery is prevented, and the use safety of the lithium battery is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle energy management control, and particularly relates to a method for calculating the vehicle on-duty time based on the SOC parameter of a lithium battery. Background Art

[0002] Due to its high energy density, the low-voltage lithium battery expands new usage scenarios for special vehicles, enabling them to have the pre-start heating on-duty function. The heating on-duty function is mainly powered by the lithium battery for the heater alone. The heater works automatically in a cycle according to the engine temperature, thus ensuring that the engine is always in a hot state, ensuring that the vehicle can be quickly started with one key under low-temperature conditions, and ensuring the mobility of the vehicle.

[0003] However, the working time of the heating on-duty is limited by the energy of the lithium battery. In addition to meeting the energy requirements during the heating on-duty process, it is also necessary to ensure that the vehicle can start smoothly under different temperature conditions. Therefore, it is necessary to provide an estimation of the time that the current battery can provide for heating on-duty, which can not only ensure the normal achievement of the vehicle starting function, but also allow the crew to have time for handling in advance, give timely suggestions for the crew's work guarantee, and at the same time prevent over-discharge of the lithium battery and ensure the safety of the lithium battery use. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] The technical problem to be solved by the present invention is: how to give a real-time estimation result of the vehicle on-duty time based on the current parameter state of the lithium battery, ensure the reliable achievement of the vehicle starting and on-duty functions, and realize the comprehensive management and application of energy.

[0006] (2) Technical Solutions

[0007] To solve the above technical problems, the present invention provides a method for calculating the vehicle on-duty time based on the SOC parameter of a lithium battery. The calculation method includes the following steps:

[0008] Step 1: Test the starting engagement voltage U 啮合 and the starting engagement current I 啮合 , as well as the starting process voltage U 起动1 and the starting process current I 起动1 during the starting process;

[0009] Step 2: Define that the starting engagement process is not less than 1 s and the starting process is not less than 30 s. Use the calculation method of multiplying the current by the voltage and then by the time to obtain the starting required energy E 起动t at the temperature t, and ensure that the currently calculated starting required energy is the maximum value that may occur;

[0010] Step 3: Test the starting engagement voltage and starting engagement current at 5°C, -20°C, and -43°C respectively, as well as the starting process voltage and starting process current during the starting process. Calculate the starting demand energy according to formula (1), and use the linear interpolation method in segments to calculate the starting demand energy at different temperatures, and give the corresponding points of the starting demand energy under different temperature conditions;

[0011] Step 4: Define the number of times the battery needs to meet the starting energy requirement;

[0012] Step 5: Obtain the battery SOC parameter requirements during starting at temperature t0;

[0013] Step 6: Calculate and obtain the vehicle standby time.

[0014] Among them, in the said Step 2, the starting demand energy E at temperature t is calculated according to the following formula (1) 起动t as:

[0015] E 起动t = U 啮合 × I 啮合 × 1 + U 起动1 × I 起动1 × 30 (1).

[0016] Among them, in the said Step 3:

[0017] The starting demand energy at different temperature points t0 within the range of 5°C and -20°C is:

[0018]

[0019] Among them, E 5℃ is the starting demand energy E when the temperature t is 5°C 起动t ;

[0020] E -20℃ is the starting demand energy E when the temperature t is -20°C 起动t ;

[0021] The starting demand energy at different temperature points t0 within the range of -20°C and -43°C is:

[0022]

[0023] E -43℃ is the starting demand energy E when the temperature t is -43°C 起动t .

[0024] Among them, in the said Step 4, it is defined that the battery needs to meet the starting energy requirement 3 times. Therefore, the starting energy possessed by the lithium battery at different temperatures should be at least E 起动总 = 3 × E 起动 ;

[0025] Among them, E 起动 According to different temperature points, in E 起动5℃至-20℃ 、

[0026] E 起动-20℃至-43℃ select.

[0027] Among them, in step 5, at temperature t0, the required SOC parameter of the battery during startup is:

[0028]

[0029] Among them, C 额定 is the rated capacity of the lithium battery, known;

[0030] U to The voltage is the current output voltage of the lithium battery, which is uploaded by the lithium battery in real time.

[0031] Among them, in step 6, the vehicle on-duty time is Δt:

[0032]

[0033] Among them, SOC 额定 is the SOC parameter value calculated by the lithium battery in real time;

[0034] E 起动 is calculated from formula (2) or formula (3);

[0035] I to The current is the discharge current of the battery, which is uploaded by the lithium battery in real time; the on-duty time of the lithium battery can be calculated through the above confirmed parameters.

[0036] Among them, the method further includes:

[0037] Step 7: Since the capacity of the vehicle lithium battery is at least 300 Ah or more, and the current during heating on-duty is about 20 Ah, therefore, the on-duty time of the vehicle is at least counted in hours. Therefore, the calculation frequency of the vehicle on-duty time is to detect and upload once every 10 minutes, reducing the computing power requirement for the controller, reducing the data uploaded on the bus, and reducing the bus load rate.

[0038] Among them, the method calculates the vehicle's available on-duty time using the lithium battery SOC parameter, which is used to ensure the realization of the heating on-duty function and starting function of special vehicles.

[0039] (III) Beneficial effects

[0040] Compared with the prior art, the present invention calculates the starting demand energy under different temperature conditions by testing the starting engagement voltage and current under different temperature conditions, real-time detects the SOC, voltage and current parameters of the lithium battery, calculates through formulas, and provides the time that the current battery can provide heating and on-duty according to a certain transmission cycle, and timely gives suggestions on the work guarantee of the crew, ensuring the reliable achievement of the vehicle starting and on-duty functions; preventing over-discharge of the lithium battery and ensuring the safety of lithium battery use. Description of the Drawings

[0041] Figure 1 It is a block diagram of the calculation principle of the vehicle on-duty time based on the SOC parameter of the lithium battery. Detailed Embodiments

[0042] To make the objectives, contents, and advantages of the present invention clearer, the following further describes in detail the specific embodiments of the present invention with reference to the drawings and embodiments.

[0043] To solve the above technical problems, the present invention provides a method for calculating the vehicle on-duty time based on the SOC parameter of the lithium battery, and the calculation method includes the following steps:

[0044] Step 1: Test the starting engagement voltage U 啮合 and the starting engagement current I 啮合 , and the starting process voltage U 起动1 and the starting process current I 起动1 during the starting process;

[0045] Step 2: Define that the starting engagement process is not less than 1 s and the starting process is not less than 30 s, and use the calculation method of multiplying the current by the voltage and then by the time to obtain the starting demand energy E 起动t at temperature t, ensuring that the currently calculated starting demand energy is the maximum value that may occur;

[0046] Step 3: Test the starting engagement voltage and starting engagement current at 5 °C, -20 °C and -43 °C respectively, as well as the starting process voltage and starting process current during the starting process, calculate the starting demand energy according to formula (1), and use the linear interpolation method in segments to calculate the starting demand energy at different temperatures, and give the corresponding points of the starting demand energy under different temperature conditions;

[0047] Step 4: Define the number of times the battery needs to meet the starting energy demand;

[0048] Step 5: Obtain the SOC parameter demand of the battery during starting at temperature t0;

[0049] Step 6: Calculate and obtain the vehicle on-duty time.

[0050] Among them, in the said step 2, the starting demand energy E at temperature t is calculated according to the following formula (1): 起动t That is:

[0051] E 起动t = U 啮合 × I 啮合 × 1 + U 起动1 × I 起动1 × 30 (1).

[0052] Among them, in the said step 3:

[0053] The starting demand energy at different temperature points t0 within the range of 5°C to -20°C is:

[0054]

[0055] Among them, E 5℃ is the starting demand energy E when the temperature t is 5°C 起动t ;

[0056] E -20℃ is the starting demand energy E when the temperature t is -20°C 起动t ;

[0057] The starting demand energy at different temperature points t0 within the range of -20°C to -43°C is:

[0058]

[0059] E -43℃ is the starting demand energy E when the temperature t is -43°C 起动t .

[0060] Among them, in the said step 4, it is defined that the battery needs to meet the starting energy demand 3 times. Therefore, the starting energy that the lithium battery has at different temperatures should be at least E 起动总 = 3 × E 起动 ;

[0061] Among them, E 起动 is selected from E 起动5℃至-20℃ ,

[0062] E 起动-20℃至-43℃ according to different temperature points.

[0063] Among them, in the said step 5, at temperature t0, the SOC parameter requirement of the battery during starting is:

[0064]

[0065] Among them, C 额定 is the rated capacity of the lithium battery, which is known;

[0066] U to The voltage is the current output voltage of the lithium battery, which is uploaded by the lithium battery in real time.

[0067] Among them, in the said step 6, the vehicle on-duty time is Δt:

[0068]

[0069] Among them, SOc 额定 is the SOC parameter value calculated by the lithium battery in real time;

[0070] E 起动 is calculated by formula (2) or formula (3);

[0071] I to The current is the discharge current of the battery, which is uploaded by the lithium battery in real time; the on-duty time of the lithium battery can be calculated through the above confirmed parameters.

[0072] Among them, the said method further includes:

[0073] Step 7: Since the capacity of the vehicle lithium battery is at least 300 Ah or more, and the current during heating on-duty is about 20 Ah, therefore, the on-duty time of the vehicle is at least counted in hours. Therefore, the calculation frequency of the vehicle on-duty time is to detect and upload once every 10 minutes, reducing the computing power requirement for the controller, reducing the data uploaded on the bus, and reducing the bus load rate.

[0074] Among them, the said method calculates the vehicle's available on-duty time using the lithium battery SOC parameter, which is used to ensure the realization of the heating on-duty function and starting function of special vehicles.

[0075] Embodiment 1

[0076] The present invention provides a method for calculating the on-duty time of a vehicle based on the lithium battery SOC parameter, including the following steps:

[0077] Step 1: The basic function of the lithium battery is to provide energy for vehicle starting. Only the energy other than meeting the starting energy requirement can be used for the realization of the vehicle's heating on-duty function. The heating on-duty function is mainly applied to low-temperature environments where the ambient temperature is lower than 5°C. Under different temperature conditions, the starting energy is different. Therefore, it is necessary to test the starting engagement voltage and current, and the voltage and current during the starting process under different temperature conditions, and calculate the starting demand energy according to the GJB298-1987 "DC 28V Electrical Characteristics" specification.

[0078] Step 2: Execute in accordance with the standard of GJB298-1987. It is pointed out in GJB298-1987 that the starting engagement process is not less than 1 s, and the starting process is not less than 30 s. To ensure a certain design margin, the calculation method of multiplying current by voltage and then by time is adopted to ensure that the energy calculated currently is the maximum value that may occur.

[0079] Starting required energy E 起动 is:

[0080] E 起动 = U 啮合 × I 啮合 × 1 + U 起动1 × I 起动1 × 30 (1)

[0081] Step 3: Test the starting engagement voltage and starting engagement current at 5°C, -20°C, and -43°C respectively, as well as the starting process voltage and starting process current during the starting process. Calculate the starting required energy according to the above formula (1), and use the linear interpolation method in segments to calculate the starting required energy at different temperatures, and give the corresponding points of the starting required energy under different temperature conditions;

[0082] The starting required energy at different temperature points t0 within the range of 5°C and -20°C is

[0083]

[0084] The starting required energy at different temperature points T0 within the range of -20°C and -43°C is

[0085]

[0086] Step 4: According to the requirements in GJB59.3, the battery needs to meet the starting energy requirements 3 times. Therefore, the starting energy of the lithium battery at different temperatures should be at least E 起动总 = 3 × E 起动

[0087] At temperature t0, the SOC parameter requirement of the battery during starting is

[0088]

[0089] Step 6: The vehicle on-duty time is Δt:

[0090]

[0091] It can be obtained from formula (5) that C 额定 is the rated capacity of the lithium battery, which is known; SOC 额定 is the SOC parameter value calculated in real time by the lithium battery; E 起动Calculated from formula (2) or formula (3); U to The voltage is the current output voltage of the lithium battery, which is uploaded in real time by the lithium battery, I to The current is the discharge current of the battery, which is uploaded in real time by the lithium battery; the duty time of the lithium battery can be calculated through the above confirmed parameters.

[0092] Step 7: Since the capacity of the vehicle lithium battery is at least 300 Ah or more, and the current during heating duty is about 20 Ah, therefore, the duty time of the vehicle is at least counted in hours. Therefore, the calculation frequency of the vehicle duty time is to detect and upload once every 10 minutes, reducing the computing power requirement for the controller, reducing the data uploaded on the bus, and reducing the bus load rate.

[0093] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A method for calculating the vehicle on-duty time based on the SOC parameter of a lithium battery, characterized in that The calculation method includes the following steps: Step 1: Test the starting engagement voltage U 啮合 and the starting engagement current I 啮合 , as well as the starting process voltage U 起动1 and the starting process current I 起动1 ; Step 2: Define that the starting engagement process is not less than 1 s and the starting process is not less than 30 s. Adopt the calculation method of multiplying current by voltage and then by time to obtain the starting required energy E at temperature t 起动t , and ensure that the currently calculated starting required energy is the maximum value that may occur; Step 3: Test the starting engagement voltage and current at 5°C, -20°C, and -43°C respectively, as well as the starting process voltage and current during the starting process. Calculate the starting demand energy according to formula (1), and use the linear interpolation method in segments to calculate the starting demand energy at different temperatures, and give the corresponding points of the starting demand energy under different temperature conditions; Step 4: Define the number of times the battery needs to meet the starting energy requirement; Step 5: Obtain the battery SOC parameter requirement during starting at temperature t0; Step 6: Calculate and obtain the vehicle standby time.

2. The vehicle on-duty time calculation method based on the SOC parameter of the lithium battery according to claim 1, wherein In step 2, the starting required energy E at temperature t is calculated according to the following formula (1) 起动t as follows: E 起动t = U 啮合 × I 啮合 × 1 + U 起动1 × I 起动1 × 30 (1).

3. The vehicle on-duty time calculation method based on the SOC parameter of the lithium battery according to claim 2, wherein, In step 3: The starting demand energy at different temperature points t0 within the range of 5°C to -20°C is: Among them, E 5℃ is the starting demand energy E at a temperature t of 5 °C 起动t ; E -20℃ is the starting required energy E at a temperature t of -20°C 起动t ; The starting demand energy at different temperature points t0 within the range of -20°C to -43°C is: E -43℃ is the starting required energy E at a temperature t of -43°C 起动t .

4. The method for calculating the vehicle on-duty time based on the SOC parameter of the lithium battery according to claim 3, wherein In the above step 4, it is defined that the storage battery needs to meet the starting energy requirement three times. Therefore, the starting energy of the lithium battery at different temperatures should be at least E 起动总 = 3 × E 起动 ; Among them, E 起动 According to different temperature points, select from E 起动5℃至-20℃ , E 起动-20℃至-43℃ for selection.

5. The vehicle on-duty time calculation method based on the SOC parameter of the lithium battery according to claim 4, characterized in that, In step 5, the battery SOC parameter requirement during starting at temperature t0 is: Among them, C 额定 is the rated capacity of the lithium battery, which is known; U to The voltage is the current output voltage of the lithium battery, which is uploaded by the lithium battery in real time.

6. The method for calculating the vehicle on-duty time based on the SOC parameter of the lithium battery according to claim 5, wherein In step 6, the vehicle standby time is Δt: Among them, SOC 额定 is the SOC parameter value calculated in real time by the lithium battery; E 起动 Calculated from formula (2) or formula (3); I to The current is the discharge current of the battery and is uploaded by the lithium battery in real time; the duty time of the lithium battery can be calculated through the above confirmed parameters.

7. The vehicle on-duty time calculation method based on the SOC parameter of the lithium battery according to claim 6, characterized in that, The method further includes: Step 7: Since the capacity of the vehicle lithium battery is at least 300 Ah or more, and the current during heating standby is about 20 Ah, the standby time of the vehicle is at least counted in hours. Therefore, the calculation frequency of the vehicle standby time is to detect and upload it every 10 minutes, reducing the computing power requirement of the controller, reducing the data uploaded on the bus, and reducing the bus load rate.

8. The vehicle on-duty time calculation method based on the SOC parameter of the lithium battery according to claim 6, characterized in that, The method calculates the vehicle's available standby time using the lithium battery SOC parameter, which is used to ensure the realization of the heating standby function and starting function of special vehicles.

9. The vehicle on-duty time calculation method based on the SOC parameter of the lithium battery according to claim 6, characterized in that, The method calculates the starting demand energy under different temperature conditions by testing the starting engagement voltage and current under different temperature conditions, real-time detects the lithium battery SOC, voltage, and current parameters, and provides the time that the current battery can provide heating standby for the crew according to a certain transmission period through formula calculation.

10. The vehicle on-duty time calculation method based on the SOC parameter of the lithium battery according to claim 6, characterized in that, The method can timely give suggestions for the crew's work guarantee, ensure the reliable achievement of the vehicle starting and standby functions; prevent over-discharge of the lithium battery and ensure the safety of lithium battery use.

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