A temperature control method for battery pack of new energy vehicle

Abstract

The present invention discloses a temperature control method for a new energy vehicle battery pack, which relates to the field of temperature monitoring technology, and includes the following steps: S1, collecting a voltage data sequence of a new energy vehicle battery pack, and generating an impact value according to the voltage data sequence; S2, determining a predicted temperature value of the new energy vehicle battery pack at the next moment according to the impact value and the temperature data sequence of the new energy vehicle battery pack; S3, starting liquid cooling when the predicted temperature value at the next moment is higher than the highest tolerable temperature. The present invention can prejudge the temperature condition of the battery pack, and perform cooling operation in advance, thereby ensuring the normal operation of the battery pack and improving the safety of new energy vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature monitoring, and in particular to a temperature control method for a battery pack of a new energy vehicle. Background Art

[0002] The development of new energy vehicles relies on efficient and stable battery systems. However, the performance of battery packs is significantly affected by temperature. Too high or too low temperatures will lead to battery capacity attenuation, reduced charging and discharging efficiency, and even safety issues such as thermal runaway. In the prior art, although there are a variety of battery temperature control methods, such as natural heating and air blast cooling technology, these methods are generally applicable to emergency start-up when the battery has abnormal temperature, and cannot predict the temperature of the battery pack, cannot predict the future temperature of the battery pack, and have the problem of slow response speed. Summary of the invention

[0003] In order to solve the above problems, the present invention proposes a temperature control method for a battery pack of a new energy vehicle.

[0004] The technical solution of the present invention is: a new energy vehicle battery pack temperature control method comprises the following steps:

[0005] S1. Collect voltage data sequence of new energy vehicle battery pack, and generate impact degree value according to the voltage data sequence;

[0006] S2. Determine the predicted temperature value of the new energy vehicle battery pack at the next moment according to the impact degree value and the temperature data sequence of the new energy vehicle battery pack;

[0007] S3. When the predicted temperature value at the next moment is higher than the maximum tolerable temperature, liquid cooling is started.

[0008] In S3, liquid cooling is used for emergency refrigeration. The circulation of coolant in the battery pack pipes can not only take away the heat, but its high specific heat capacity can also effectively absorb the heat generated by the battery cells, quickly reducing the battery pack temperature and preventing thermal runaway.

[0009] Furthermore, S1 includes the following sub-steps:

[0010] S11, obtaining a disturbance phase voltage waveform of a new energy vehicle battery pack, and determining a disturbance factor corresponding to the disturbance phase voltage waveform;

[0011] S12, collecting voltage values ​​of new energy vehicle battery packs at historical moments to form a voltage data sequence;

[0012] S13, constructing a loss function for the voltage data sequence;

[0013] S14. Calculate the impact value according to the disturbance factor corresponding to the disturbance phase voltage waveform and the loss function of the voltage data sequence.

[0014] The beneficial effect of the above further scheme is: in the present invention, in the disturbance analysis of the battery voltage, when a disturbance voltage is applied to the battery, a response current with the same frequency as the disturbance voltage will be generated inside the battery, and both are usually expressed as sinusoidal waveforms, but may not be pure sinusoidal waves. Therefore, the present invention calculates the disturbance factor according to the amplitude of the disturbance phase voltage waveform, and brings the disturbance factor into the calculation of the impact degree value. Then, according to the change of voltage in the entire historical time, the impact degree value characterizing the characteristics of the voltage data is determined.

[0015] Furthermore, in S11, the disturbance factor corresponding to the disturbance phase voltage waveform is The calculation formula is:

[0016] ;

[0017] In the formula, represents the amplitude of the first moment in the disturbance phase voltage waveform, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, represents the maximum value function, Indicates rounding up operation. Represents the total number of moments of the disturbed phase voltage waveform.

[0018] The beneficial effect of the above further scheme is: in the present invention, the waveform factor is the ratio of the effective value to the average value, which is used to describe the degree of deviation of the waveform from the ideal sine wave. For a sine wave, the waveform factor is 1.414. The disturbed phase voltage waveform may not be a pure sine wave, but a sine wave containing a disturbance signal. Therefore, the waveform factor is brought into the calculation of the disturbance factor to improve the accuracy of the disturbance factor.

[0019] Furthermore, in S13, the loss function of the voltage data sequence is The expression is:

[0020] ;

[0021] In the formula, Indicates the voltage value of the new energy vehicle battery pack at the first historical moment, Indicates that new energy vehicle battery packs are The voltage value at a historical moment, Indicates that new energy vehicle battery packs are The voltage value at a historical moment, Indicates the maximum voltage value of the new energy vehicle battery pack at all historical moments, Indicates the minimum voltage value of the new energy vehicle battery pack at all historical moments, represents the logarithmic function, Represents the total number of historical moments.

[0022] Furthermore, in S14, the impact value The calculation formula is:

[0023] ;

[0024] In the formula, represents the loss function of the voltage data series, Represents the disturbance factor corresponding to the disturbed phase voltage waveform.

[0025] Furthermore, S2 includes the following sub-steps:

[0026] S21. Generate an impact factor according to the electromotive force temperature coefficient and impact degree value of the new energy vehicle battery pack;

[0027] S22, collecting temperature values ​​of new energy vehicle battery packs at historical moments to form a temperature data sequence;

[0028] S23, forming an adjacent temperature matrix of two rows and one column by combining the temperature values ​​at adjacent moments in the temperature data sequence, and generating a historical temperature coefficient for the temperature data sequence;

[0029] S24. Multiply the historical temperature coefficient by the influencing factor to obtain the predicted temperature value of the new energy vehicle battery pack at the next moment.

[0030] The beneficial effect of the above further scheme is that: in the present invention, the electromotive force temperature coefficient refers to the change value of the voltage when the temperature of the battery changes by 1°C. In the present invention, the temperature value, the electromotive force temperature coefficient and the influence degree value can be dimensionless. By using the above parameters to predict the temperature value of the battery pack at the next moment, the parameters considered are relatively comprehensive, which can greatly improve the accuracy of the prediction.

[0031] Furthermore, in S21, the impact factor The calculation formula is:

[0032] ;

[0033] In the formula, Indicates the electromotive force temperature coefficient of the new energy vehicle battery pack, Indicates the impact value. Represents an exponent.

[0034] Furthermore, in S23, the historical temperature coefficient The calculation formula is:

[0035] ;

[0036] ;

[0037] ;

[0038] ;

[0039] In the formula, Indicates the temperature value of the new energy vehicle battery pack at the first historical moment, Represents the adjacent temperature matrix of the new energy vehicle battery pack at the first historical moment, represents the mean of two elements in the adjacent temperature matrix of the new energy vehicle battery pack at the first historical moment, Indicates that new energy vehicle battery packs are The temperature value at a historical moment, Indicates that new energy vehicle battery packs are The adjacent temperature matrix of historical moments, Indicates that new energy vehicle battery packs are The mean of two elements in the adjacent temperature matrix at historical moments, Indicates that new energy vehicle battery packs are The temperature value at a historical moment, Indicates that new energy vehicle battery packs are The adjacent temperature matrix of historical moments, Indicates that new energy vehicle battery packs are The mean of two elements in the adjacent temperature matrix at historical moments, Represents the F-norm operation.

[0040] The beneficial effects of the present invention are as follows: the present invention constructs a loss function for the voltage data sequence of the new energy vehicle battery pack, and then generates an influence degree value in combination with the disturbance factor; then the influence degree value and the temperature data sequence are combined to determine the predicted temperature value of the battery pack, thereby determining whether to start liquid cooling for emergency cooling; the present invention can predict the temperature condition of the battery pack and perform cooling operations in advance to ensure the normal operation of the battery pack and improve the safety of new energy vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The figure is a flow chart of a temperature control method for a battery pack of a new energy vehicle. DETAILED DESCRIPTION

[0042] The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

[0043] like Figure 1 As shown, the present invention provides a new energy vehicle battery pack temperature control method, comprising the following steps:

[0044] S1. Collect voltage data sequence of new energy vehicle battery pack, and generate impact degree value according to the voltage data sequence;

[0045] S2. Determine the predicted temperature value of the new energy vehicle battery pack at the next moment based on the impact degree value and the temperature data sequence of the new energy vehicle battery pack;

[0046] S3. When the predicted temperature value at the next moment is higher than the maximum tolerable temperature, liquid cooling is started.

[0047] In S3, liquid cooling is used for emergency refrigeration. The circulation of coolant in the battery pack pipes can not only take away the heat, but its high specific heat capacity can also effectively absorb the heat generated by the battery cells, quickly reducing the battery pack temperature and preventing thermal runaway.

[0048] In this embodiment of the present invention, S1 includes the following sub-steps:

[0049] S11, obtaining a disturbance phase voltage waveform of a new energy vehicle battery pack, and determining a disturbance factor corresponding to the disturbance phase voltage waveform;

[0050] S12, collecting voltage values ​​of new energy vehicle battery packs at historical moments to form a voltage data sequence;

[0051] S13, constructing a loss function for the voltage data sequence;

[0052] S14. Calculate the impact value according to the disturbance factor corresponding to the disturbance phase voltage waveform and the loss function of the voltage data sequence.

[0053] In the present invention, in the disturbance analysis of battery voltage, when a disturbance voltage is applied to the battery, a response current with the same frequency as the disturbance voltage will be generated inside the battery, and both are usually expressed as sinusoidal waveforms, but may not be pure sinusoidal waves. Therefore, the present invention calculates the disturbance factor based on the amplitude of the disturbance phase voltage waveform, and brings the disturbance factor into the calculation of the impact value. Then, based on the change of voltage in the entire historical time, the impact value that characterizes the characteristics of the voltage data is determined.

[0054] In the embodiment of the present invention, in S11, the disturbance factor corresponding to the disturbance phase voltage waveform is The calculation formula is:

[0055] ;

[0056] In the formula, represents the amplitude of the first moment in the disturbance phase voltage waveform, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, represents the maximum value function, Indicates rounding up operation. Represents the total number of moments of the disturbed phase voltage waveform.

[0057] In the present invention, the waveform factor is the ratio of the effective value to the average value, which is used to describe the degree of deviation of the waveform from the ideal sine wave. For a sine wave, the waveform factor is 1.414. The disturbed phase voltage waveform may not be a pure sine wave, but a sine wave containing a disturbance signal. Therefore, the waveform factor is brought into the calculation of the disturbance factor to improve the accuracy of the disturbance factor.

[0058] In the embodiment of the present invention, in S13, the loss function of the voltage data sequence is The expression is:

[0059] ;

[0060] In the formula, Indicates the voltage value of the new energy vehicle battery pack at the first historical moment, Indicates that new energy vehicle battery packs are The voltage value at a historical moment, Indicates that new energy vehicle battery packs are The voltage value at a historical moment, Indicates the maximum voltage value of the new energy vehicle battery pack at all historical moments, Indicates the minimum voltage value of the new energy vehicle battery pack at all historical moments, represents the logarithmic function, Represents the total number of historical moments.

[0061] In the embodiment of the present invention, in S14, the impact degree value The calculation formula is:

[0062] ;

[0063] In the formula, represents the loss function of the voltage data series, Represents the disturbance factor corresponding to the disturbed phase voltage waveform.

[0064] In this embodiment of the present invention, S2 includes the following sub-steps:

[0065] S21. Generate an impact factor according to the electromotive force temperature coefficient and impact degree value of the new energy vehicle battery pack;

[0066] S22, collecting temperature values ​​of new energy vehicle battery packs at historical moments to form a temperature data sequence;

[0067] S23, forming an adjacent temperature matrix of two rows and one column by combining the temperature values ​​at adjacent moments in the temperature data sequence, and generating a historical temperature coefficient for the temperature data sequence;

[0068] S24. Multiply the historical temperature coefficient by the influencing factor to obtain the predicted temperature value of the new energy vehicle battery pack at the next moment.

[0069] In the present invention, the electromotive force temperature coefficient refers to the change in voltage when the temperature of the battery changes by 1°C. In the present invention, the temperature value, electromotive force temperature coefficient and impact value can be dimensionless. The above parameters are used to predict the temperature value of the battery pack at the next moment, and the parameters considered are more comprehensive, which can greatly improve the accuracy of the prediction.

[0070] In the embodiment of the present invention, in S21, the impact factor The calculation formula is:

[0071] ;

[0072] In the formula, Indicates the electromotive force temperature coefficient of the new energy vehicle battery pack, Indicates the impact value. Represents an exponent.

[0073] In the embodiment of the present invention, in S23, the historical temperature coefficient The calculation formula is:

[0074] ;

[0075] ;

[0076] ;

[0077] ;

[0078] In the formula, Indicates the temperature value of the new energy vehicle battery pack at the first historical moment, Represents the adjacent temperature matrix of the new energy vehicle battery pack at the first historical moment, represents the mean of two elements in the adjacent temperature matrix of the new energy vehicle battery pack at the first historical moment, Indicates that new energy vehicle battery packs are The temperature value at a historical moment, Indicates that new energy vehicle battery packs are The adjacent temperature matrix of historical moments, Indicates that new energy vehicle battery packs are The mean of two elements in the adjacent temperature matrix at historical moments, Indicates that new energy vehicle battery packs are The temperature value at a historical moment, Indicates that new energy vehicle battery packs are The adjacent temperature matrix of historical moments, Indicates that new energy vehicle battery packs are The mean of two elements in the adjacent temperature matrix at historical moments, Represents the F-norm operation.

[0079] The temperature values ​​of the current moment and the next moment are arranged as the adjacent temperature matrix of the current moment. The adjacent temperature matrix of the last moment is obtained by arranging the temperature value of the last moment and the temperature of the first moment.

[0080] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A temperature control method for a new energy vehicle battery pack, characterized in that: The following steps are involved: S1. Collect voltage data sequence of new energy vehicle battery pack, and generate impact degree value according to the voltage data sequence; S2. Determine the predicted temperature value of the new energy vehicle battery pack at the next moment according to the impact degree value and the temperature data sequence of the new energy vehicle battery pack; S3, when the predicted temperature value at the next moment is higher than the maximum tolerable temperature, liquid cooling is started; The S1 comprises the following sub-steps: S11, obtaining a disturbance phase voltage waveform of a new energy vehicle battery pack, and determining a disturbance factor corresponding to the disturbance phase voltage waveform; S12, collecting voltage values ​​of new energy vehicle battery packs at historical moments to form a voltage data sequence; S13, constructing a loss function for the voltage data sequence; S14, calculating the impact value according to the disturbance factor corresponding to the disturbance phase voltage waveform and the loss function of the voltage data sequence; In S11, the disturbance factor corresponding to the disturbance phase voltage waveform is The calculation formula is: ； In the formula, represents the amplitude of the first moment in the disturbance phase voltage waveform, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, Indicates the first part of the disturbance phase voltage waveform The amplitude at a moment, represents the maximum value function, Indicates rounding up operation. The total number of moments representing the disturbed phase voltage waveform; In S14, the impact degree value The calculation formula is: ； In the formula, represents the loss function of the voltage data series, Represents the disturbance factor corresponding to the disturbed phase voltage waveform.

2. The temperature control method of the new energy vehicle battery pack according to claim 1, characterized in that: In S13, the loss function of the voltage data sequence is The expression is: ； In the formula, Indicates the voltage value of the new energy vehicle battery pack at the first historical moment, Indicates that new energy vehicle battery packs are The voltage value at a historical moment, Indicates that new energy vehicle battery packs are The voltage value at a historical moment, Indicates the maximum voltage value of the new energy vehicle battery pack at all historical moments, Indicates the minimum voltage value of the new energy vehicle battery pack at all historical moments, represents the logarithmic function, Represents the total number of historical moments.

3. The temperature control method of the new energy vehicle battery pack according to claim 1, characterized in that: The S2 comprises the following sub-steps: S21. Generate an impact factor according to the electromotive force temperature coefficient and impact degree value of the new energy vehicle battery pack; S22, collecting temperature values ​​of new energy vehicle battery packs at historical moments to form a temperature data sequence; S23, forming an adjacent temperature matrix of two rows and one column by combining the temperature values ​​at adjacent moments in the temperature data sequence, and generating a historical temperature coefficient for the temperature data sequence; S24. Multiply the historical temperature coefficient by the influencing factor to obtain the predicted temperature value of the new energy vehicle battery pack at the next moment.

4. The temperature control method of the new energy vehicle battery pack according to claim 3, characterized in that: The S21 impact factor The calculation formula is: ； In the formula, Indicates the electromotive force temperature coefficient of the new energy vehicle battery pack, Indicates the impact value. Represents an exponent.

5. The temperature control method of the new energy vehicle battery pack according to claim 3, characterized in that: The S23, historical temperature coefficient The calculation formula is: ； ； ； ； In the formula, Indicates the temperature value of the new energy vehicle battery pack at the first historical moment, Represents the adjacent temperature matrix of the new energy vehicle battery pack at the first historical moment, represents the mean of two elements in the adjacent temperature matrix of the new energy vehicle battery pack at the first historical moment, Indicates that new energy vehicle battery packs are The temperature value at a historical moment, Indicates that new energy vehicle battery packs are The adjacent temperature matrix of historical moments, Indicates that new energy vehicle battery packs are The mean of two elements in the adjacent temperature matrix at historical moments, Indicates that new energy vehicle battery packs are The temperature value at a historical moment, Indicates that new energy vehicle battery packs are The adjacent temperature matrix of historical moments, Indicates that new energy vehicle battery packs are The mean of two elements in the adjacent temperature matrix at historical moments, Represents the F-norm operation.

Images