Battery voltage measurement method, device, medium and vehicle

Abstract

The present disclosure relates to a battery voltage measurement method, device, medium and vehicle, including: determining the current frequency and current peak value of the alternating current input into the battery; collecting the instantaneous current value and instantaneous voltage value in the battery at the same time; determining the target phase difference according to the current frequency and the target relationship function; determining the voltage peak value of the voltage waveform according to the instantaneous current value, current frequency, current peak value, instantaneous voltage value of the battery and the target phase difference, and using the voltage peak value as the measurement voltage. The problem that the sampling frequency of the current measurement circuit or chip for battery voltage is not high and cannot meet the voltage sampling requirements in high-frequency AC working conditions is solved, and there is no need to change the existing hardware structure, thereby reducing the voltage measurement cost in high-frequency AC working conditions.

Description

Technical Field

[0001] The present disclosure relates to the field of batteries, and in particular, to a battery voltage measurement method, device, medium and vehicle. Background Art

[0002] As electric vehicles become more and more popular, the scenarios in which they are used have become more extensive. Similarly, the disadvantages of power batteries represented by lithium batteries have become more well known to the public. Temperature has an important impact on lithium batteries. Too low a temperature will not only cause the performance of lithium batteries to decline and fail to work properly, but charging at low temperatures will also cause lithium deposition at the negative electrode, causing the battery capacity to decay rapidly, and in extreme cases even causing the positive and negative electrodes to break. Therefore, in order for lithium batteries to work properly in low temperature environments, they need to be equipped with a heating device to increase the temperature of the lithium batteries.

[0003] The commonly used internal heating method for batteries is self-heating, such as AC heating. AC heating is achieved by applying an AC current to both ends of the battery and utilizing the internal impedance of the lithium battery to heat the battery. Since the direction of the AC current is always changing rapidly, the attenuation of the battery capacity caused by the discharge heating process of the large DC current is avoided. During the AC heating process, the faster the frequency and the greater the current amplitude, the faster the fluctuation range and change speed of the battery terminal voltage. In order to ensure that the battery terminal voltage is always within a safe range, a reliable voltage sampling circuit or sampling strategy is required to ensure accurate monitoring of the battery terminal voltage during the AC heating process, to ensure that the battery is not in an overcharged / over-discharged state, thereby avoiding safety risks such as lithium deposition in the battery.

[0004] However, the sampling frequency of existing sampling circuits or sampling chips is not high, generally only a few hundred hertz, and is only suitable for general DC charging / discharging, or battery voltage detection under low-frequency AC conditions. However, the current frequency in general AC self-heating methods often reaches the kilohertz level or higher. The existing sampling methods cannot meet the voltage sampling requirements under high-frequency AC conditions. Summary of the invention

[0005] The purpose of the present disclosure is to provide a battery voltage measurement method, device, medium and vehicle, which are used to solve the problem that the sampling frequency of the current battery voltage measurement circuit or chip is not high enough to meet the voltage sampling requirements in high-frequency AC working conditions, and there is no need to modify the existing hardware structure, thereby reducing the voltage measurement cost in high-frequency AC working conditions. .

[0006] In order to achieve the above object, the present disclosure provides a battery voltage measurement method, the method comprising:

[0007] Determine the current frequency and current peak value of the alternating current input into the battery;

[0008] Simultaneously collecting the instantaneous current value and the instantaneous voltage value in the battery;

[0009] determining a target phase difference according to the current frequency and a target relationship function, wherein the target phase difference is a phase difference between a current waveform of the alternating current input into the battery and a voltage waveform generated in the battery, and the target relationship function is a pre-set relationship function representing a corresponding relationship between the current frequency and the target phase difference;

[0010] The voltage peak value of the voltage waveform is determined based on the battery instantaneous current value, the current frequency, the current peak value, the battery instantaneous voltage value, and the target phase difference, and the voltage peak value is used as the measurement voltage.

[0011] Optionally, the method further comprises:

[0012] Obtaining battery specifications of the battery, wherein the battery specifications at least include battery materials;

[0013] A relationship function corresponding to the battery specification is determined as the target relationship function.

[0014] Optionally, the current frequency of the alternating current input into the battery is greater than a preset frequency threshold,

[0015] Wherein, when the current frequency is greater than the preset frequency threshold, the battery exhibits an inductive reactance characteristic.

[0016] Optionally, the target relationship function is determined by the following method:

[0017] constructing an equivalent circuit model of the battery;

[0018] The model parameters in the equivalent circuit model are obtained by testing a first battery model, wherein the first battery model is an actual battery that is the same as the battery and is used for testing;

[0019] Constructing a second battery model according to the model parameters, wherein the second battery model is a digital simulation battery identical to the battery;

[0020] The simulated current waveforms of different current frequencies are respectively input into the second battery model to obtain the simulated voltage waveforms corresponding to the output of the second battery model, and the target relationship function is determined according to the phase difference between each simulated current waveform and its corresponding simulated voltage waveform, and the current peak value of each simulated current waveform.

[0021] Optionally, the equivalent circuit model includes a first polarization resistor, a first polarization capacitor, a second polarization resistor, a second polarization capacitor, an inductive resistor, an inductor, and an ohmic internal resistance.

[0022] The first polarization resistor and the first polarization capacitor are connected in parallel and then connected in series with the ohmic internal resistor. The second polarization resistor and the second polarization capacitor are connected in parallel and then connected in series with the ohmic internal resistor. The inductive resistor and the inductor are connected in parallel and then connected in series with the ohmic internal resistor.

[0023] Optionally, the test performed on the first battery model includes: a hybrid power pulse capability characteristic HPPC test and an electrochemical impedance spectroscopy EIS test, wherein:

[0024] The hybrid power pulse capability characteristic HPPC test is used to detect the values ​​of the ohmic internal resistance, the first polarization resistance, the second polarization resistance, the first polarization capacitance and the second polarization capacitance, and the electrochemical impedance spectroscopy EIS test is used to detect the value of the inductance;

[0025] The value of the inductor resistance is calculated based on the detected values ​​of the ohmic internal resistance, the first polarization resistance, the second polarization resistance, the first polarization capacitance, the second polarization capacitance and the inductance.

[0026] Optionally, the inductor resistance is calculated according to the following formula:

[0027]

[0028] Wherein, R1 is the first polarization resistor, R2 is the second polarization resistor, C1 is the first polarization capacitor, C2 is the second polarization capacitor, R3 is the inductor resistor, L is the inductor, R0 is the ohmic internal resistance, I rms is the effective value of the current in the first battery model, ΔUt is the peak voltage in the first battery model, f is the current or voltage fluctuation frequency in the first battery model, and the effective value of the current ΔUt, the peak voltage I rms , the frequency f is a known value during the test.

[0029] Optionally, the value of the inductance obtained by the electrochemical impedance spectroscopy (EIS) test is the value of the inductance when the current frequency of the simulated current waveform is at a maximum value.

[0030] Optionally, the method further comprises:

[0031] When the measured voltage exceeds a voltage threshold range corresponding to the battery, the current frequency and / or the current peak value of the alternating current input into the battery is adjusted to keep the battery voltage within the voltage threshold range.

[0032] The present disclosure also provides a battery voltage measurement device, the device comprising:

[0033] A first determination module is used to determine the current frequency and current peak value of the alternating current input into the battery;

[0034] A collection module, used for simultaneously collecting the instantaneous current value and the instantaneous voltage value in the battery;

[0035] A second determination module is used to determine a target phase difference according to the current frequency and a target relationship function, wherein the target phase difference is a phase difference between a current waveform of the alternating current input into the battery and a voltage waveform generated in the battery, and the target relationship function is a preset relationship function representing a corresponding relationship between the current frequency and the target phase difference;

[0036] The measuring module is used to determine the voltage peak value of the voltage waveform according to the instantaneous current value of the battery, the current frequency, the current peak value, the instantaneous voltage value of the battery and the target phase difference, and use the voltage peak value as the measuring voltage.

[0037] The present disclosure also provides a computer-readable storage medium having a computer program stored thereon, wherein the program implements the steps of the above method when executed by a processor.

[0038] The present disclosure also provides a vehicle, comprising the battery voltage measuring device described above.

[0039] Through the above technical scheme, the corresponding relationship between the current frequency of the alternating current in the battery and the target phase difference is determined in advance, so that after the current frequency and current peak of the alternating current input to the battery are determined, the voltage peak of the alternating voltage corresponding to the alternating current can be estimated according to the acquired instantaneous current value and instantaneous voltage value, thereby achieving the purpose of measuring the battery voltage, solving the problem that the sampling frequency of the current battery voltage measurement circuit or chip is not high and cannot meet the voltage sampling requirements in high-frequency AC working conditions, and there is no need to change the existing hardware structure, thereby reducing the voltage measurement cost in high-frequency AC working conditions.

[0040] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0042] Figure 1The figure is a flow chart of a method for measuring battery voltage according to an exemplary embodiment of the present disclosure.

[0043] Figure 2 is a flow chart showing a method for determining battery voltage according to yet another exemplary embodiment of the present disclosure.

[0044] Figure 3 The present invention is a flowchart of a method for determining a target relationship function in a battery voltage determination method according to an exemplary embodiment of the present disclosure.

[0045] Figure 4 It is a structural schematic diagram of an equivalent circuit model of a battery in a battery voltage measurement method according to an exemplary embodiment of the present disclosure.

[0046] Figure 5 is a flow chart showing a method for determining battery voltage according to yet another exemplary embodiment of the present disclosure.

[0047] Figure 6 The figure is a structural block diagram of a battery voltage measuring device according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0048] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0049] Figure 1 FIG. 1 is a flow chart of a method for measuring battery voltage according to an exemplary embodiment of the present disclosure. Figure 1 As shown, the method includes steps 101 to 104.

[0050] In step 101, the current frequency and current peak value of the alternating current input into the battery are determined. The battery may be a power lithium battery in a vehicle, and the alternating current input into the battery may be, for example, alternating current for realizing self-heating of the battery. The current frequency and current peak value of the alternating current input into the battery are controllable and can be adjusted to a certain extent according to the actual use of the alternating current. Therefore, before measuring the battery voltage, the current frequency and current peak value of the alternating current currently input into the battery may be determined first.

[0051] In step 102, the instantaneous current value and the instantaneous voltage value in the battery are collected simultaneously.

[0052] The instantaneous current value and the instantaneous voltage value can be collected by a conventional current collection chip and a voltage collection chip. Since only the current value and the voltage value at a certain moment need to be collected, the collection frequency of the current value and the voltage value does not need to be too high.

[0053] In step 103, a target phase difference is determined based on the current frequency and a target relationship function, wherein the target phase difference is the phase difference between the current waveform of the alternating current input into the battery and the voltage waveform generated in the battery, and the target relationship function is a pre-set relationship function representing the corresponding relationship between the current frequency and the target phase difference.

[0054] The target phase difference may be determined in advance through experiments. When the current frequency of the alternating current input into the battery is constant, the phase difference between the voltage waveform of the alternating voltage generated in the battery and the current waveform of the alternating current is fixed. Therefore, as long as the current frequency of the alternating current input into the battery is determined, the phase difference between the corresponding current waveform and voltage waveform can be determined.

[0055] In step 104 , a voltage peak value of the voltage waveform is determined based on the battery instantaneous current value, the current frequency, the current peak value, the battery instantaneous voltage value, and the target phase difference, and the voltage peak value is used as a measured voltage.

[0056] Since the frequency of the voltage waveform is the same as the current frequency, after the target phase difference is determined based on the current frequency and the target relationship function, and the current frequency and current peak of the alternating current, as well as the current instantaneous current value and instantaneous voltage value in the battery are determined, the current time point can be determined first by the current frequency, current peak and instantaneous current value, and then the determined time point, phase difference and instantaneous voltage value can be substituted into the expression of the voltage waveform to reversely obtain the voltage peak value of the voltage waveform.

[0057] Wherein, when the alternating current is a sine wave, the expression of the current waveform is usually, for example, i=Asin(ω·t). Since there is a phase difference between the voltage waveform and the current waveform, the expression of the voltage waveform can be, for example, v=Bsin(ω·t+θ), where i is the instantaneous current value, A is the current peak value, ω is the angular frequency, t is time, v is the instantaneous voltage value, B is the voltage peak value, and θ is the target phase difference. The angular frequency can be determined by a fixed mapping relationship with the current frequency. For example, if the current frequency and the voltage frequency are represented by f, then ω=2πf.

[0058] Through the above technical scheme, the corresponding relationship between the current frequency of the alternating current in the battery and the target phase difference is determined in advance, so that after the current frequency and current peak of the alternating current input to the battery are determined, the voltage peak of the alternating voltage corresponding to the alternating current can be estimated according to the acquired instantaneous current value and instantaneous voltage value, thereby achieving the purpose of measuring the battery voltage, solving the problem that the sampling frequency of the current battery voltage measurement circuit or chip is not high and cannot meet the voltage sampling requirements in high-frequency AC working conditions, and there is no need to change the existing hardware structure, thereby reducing the voltage measurement cost in high-frequency AC working conditions.

[0059] Figure 2 FIG. 1 is a flow chart of a method for measuring battery voltage according to another exemplary embodiment of the present disclosure. Figure 2 As shown, the method further includes steps 201 and 202.

[0060] In step 201, the battery specification of the battery is obtained, and the battery specification at least includes battery materials.

[0061] In step 202, a relationship function corresponding to the battery specification is determined as the target relationship function.

[0062] The target relationship function corresponding to different battery specifications may be different, and the target relationship function corresponding to different battery specifications can be obtained by conducting experiments on batteries of different battery specifications. For example, for a battery whose positive electrode material is lithium iron phosphate, an experiment can be conducted to obtain the corresponding target relationship function, and for a battery whose corresponding battery material is other, another experiment can be conducted to obtain the corresponding target relationship function.

[0063] The battery specification may include not only the battery material but also the battery capacity. For example, for a battery whose positive electrode material is lithium iron phosphate, batteries of different capacities may also be subjected to corresponding experiments to obtain corresponding target relationship functions.

[0064] The execution order of the above steps 201 and 202 can be as follows: Figure 2 It is shown as being performed before step 101 , or it may also be performed before step 103 , as long as it can be ensured that the target relationship function can be determined before executing step 103 .

[0065] Through the above technical solution, the corresponding target relationship function can be determined according to different battery specifications, so that a more accurate phase difference corresponding to the battery can be obtained, thereby making the measured voltage peak more accurate.

[0066] In a possible implementation manner, the current frequency of the alternating current input into the battery is greater than a preset frequency threshold, wherein when the current frequency is greater than the preset frequency threshold, the battery exhibits an inductive reactance characteristic.

[0067] When a bipolar power supply is used to input an alternating current signal of a certain frequency and amplitude to the battery, the battery will output a corresponding voltage signal, and the current frequency of the alternating current signal will affect the phase relationship between the voltage signal and the current signal, and different phase relationships will affect the impedance characteristics of the battery. When the current frequency is low, the voltage waveform lags behind the current waveform, and the impedance characteristics of the battery are polarized capacitive reactance characteristics; at medium frequency, the voltage waveform and current waveform of the battery coincide, the polarized capacitive reactance and inductive reactance of the battery cancel each other out, and the impedance characteristics of the battery are resistive characteristics; at high frequency, the current waveform of the battery lags behind the voltage waveform, the polarized capacitive reactance of the battery is very small, and the impedance characteristics of the battery are inductive reactance characteristics. However, when the voltage waveform lags behind the current waveform, that is, when the impedance characteristic of the battery presents a capacitive reactance characteristic, the battery may cause lithium deposition when running for a long time at low temperature. The alternating current input into the battery is usually used for battery self-heating, and the battery temperature is usually low at this time. Therefore, the current frequency of the alternating current input into the battery needs to be greater than the preset frequency threshold to ensure that the impedance characteristic of the battery is always within the inductive reactance range to avoid safety risks to the battery.

[0068] The preset frequency threshold may be any frequency value that can make the battery present an inductive reactance characteristic, as long as it can be ensured that the current frequency of the alternating current input into the battery is greater than the preset frequency threshold, the battery can present an inductive reactance characteristic.

[0069] In a possible implementation, the target relationship function is expressed as follows: Figure 3 The method shown is determined to include steps 301 to 304.

[0070] In step 301, an equivalent circuit model of the battery is constructed. The equivalent circuit model can be as follows: Figure 4 As shown, it includes a first polarization resistor R1, a first polarization capacitor C1, a second polarization resistor R2, a second polarization capacitor C2, an inductor resistor R3, an inductor L and an ohmic internal resistor R0. The first polarization resistor R1 and the first polarization capacitor C1 are connected in parallel and then connected in series with the ohmic internal resistor R0. The second polarization resistor R2 and the second polarization capacitor C2 are also connected in parallel and then connected in series with the ohmic internal resistor R0. The inductor resistor R3 and the inductor L are also connected in parallel and then connected in series with the ohmic internal resistor R0.

[0071] In step 302, the model parameters in the equivalent circuit model are obtained by testing a first battery model, wherein the first battery model is an actual battery that is the same as the battery and is used for testing.

[0072] For example, Figure 2 As shown in the case where the corresponding target relationship function is selected according to the battery specifications, the first battery model can be, for example, a battery consistent with the battery specifications. That is, if the battery corresponding to the target relationship function to be determined is a battery whose positive electrode material is lithium iron phosphate, the first battery model can also be a real battery whose positive electrode material is lithium iron phosphate.

[0073] The tests performed on the first battery model may include: a hybrid pulse power characteristic HPPC (Hybrid Pulse Power Characteristic) test and an electrochemical impedance spectroscopy EIS (Electrochemical impedance spectroscopy) test, wherein the hybrid pulse power characteristic HPPC test is used to detect the values ​​of the ohmic internal resistance R0, the first polarization resistor R1, the second polarization resistor R2, the first polarization capacitor C1 and the second polarization capacitor C2, and the electrochemical impedance spectroscopy EIS test is used to detect the value of the inductance L; the value of the inductance resistor R3 is calculated based on the detected values ​​of the ohmic internal resistance R0, the first polarization resistor R2, the second polarization resistor R3, the first polarization capacitor C1, the second polarization capacitor C2 and the inductance L.

[0074] When calculating the value of the inductor resistor R3, it can be calculated using the following formula:

[0075]

[0076] Wherein, R1 is the first polarization resistor, R2 is the second polarization resistor, C1 is the first polarization capacitor, C2 is the second polarization capacitor, R3 is the inductor resistor, L is the inductor, R0 is the ohmic internal resistance, I rms is the effective value of the current in the first battery model, ΔUt is the peak voltage in the first battery model, f is the current or voltage fluctuation frequency in the first battery model, and the effective value of the current ΔUt, the peak voltage I rms , the frequency f is a known value during the test.

[0077] In the equivalent circuit model, the voltage U1 across the first polarized resistor R1 and the first polarized capacitor C1, the voltage U2 across the second polarized resistor R2 and the second polarized capacitor C2, and the voltage U3 across the inductor and the inductor resistor can be expressed by the following formulas (2) to (4), respectively:

[0078]

[0079]

[0080]

[0081] Thus, we can get the following formula (5), where That is, the current peak value in the first battery model.

[0082]

[0083] By transforming the formula (5), the formula (1) can be obtained to calculate the value of the inductor resistor R3.

[0084] In step 303, a second battery model is constructed according to the model parameters, and the second battery model is a digital simulation battery that is the same as the battery. After the model parameters in the equivalent circuit model of the battery are determined by testing, a simulation battery model corresponding to the battery, i.e., the second battery model, can be established. The second battery model can be constructed by, for example, the functional component Simulink in MATLAB.

[0085] In a possible implementation, the value of the inductance L obtained according to the electrochemical impedance spectroscopy EIS test is the value of the inductance when the current frequency of the simulated current waveform is at its maximum value, that is, when determining the value of the inductance according to the electrochemical impedance spectroscopy EIS test, the maximum frequency of the simulated current waveform that will be used in subsequent simulation of the second battery model can be used.

[0086] In step 304, simulated current waveforms of different current frequencies are respectively input into the second battery model to obtain simulated voltage waveforms corresponding to the outputs of the second battery model, and the target relationship function is determined based on the phase difference between each simulated current waveform and its corresponding simulated voltage waveform, and the current peak value of each simulated current waveform.

[0087] In a possible implementation, in addition to using simulated current waveforms of different current frequencies, simulated current waveforms of different current peak values ​​can also be used to obtain different simulated voltage waveforms, so that it can be determined whether the peak value of the simulated voltage waveform output by the second battery model will exceed the upper and lower voltage limits of the first battery model corresponding to the second battery model when the simulated current waveforms of different current peak values ​​and different current frequencies are input into the second battery model, and thus the voltage can be guaranteed to be safe when used in actual use. Figure 1In step 101 shown in FIG. 1 , the current frequency and current peak value of the alternating current input into the battery play a certain restrictive role.

[0088] Figure 5 is a flow chart of a battery voltage determination method according to another exemplary embodiment of the present disclosure. Figure 5 As shown, the method further includes step 501.

[0089] In step 501, when the measured voltage exceeds the voltage threshold range corresponding to the battery, the current frequency and / or the current peak value of the alternating current input into the battery are adjusted to keep the battery voltage within the voltage threshold range.

[0090] For example, if it is found that the measured voltage exceeds the upper or lower limit of the voltage threshold range, the current peak value of the alternating current (that is, the effective value of the current is appropriately reduced) and / or the current frequency can be appropriately reduced to achieve the purpose of reducing the measured voltage and ensure that it does not exceed the normal voltage upper and lower limits.

[0091] In addition, since the alternating current can be an alternating current used for battery self-heating, if it is found that the measured voltage does not exceed the upper or lower limit of the voltage threshold range, the current peak value of the alternating current (that is, the effective current value) and / or the current frequency can be appropriately increased to increase the self-heating heat generation and enhance the heating effect.

[0092] Through the above technical solution, when the battery voltage is accurately measured, the alternating current can be controlled more accurately to ensure that the battery voltage does not exceed the safe range, and the self-heating efficiency can be maximized when the alternating current is the current used for battery self-heating.

[0093] Figure 6 FIG. 1 is a structural block diagram of a battery voltage measuring device according to an exemplary embodiment of the present disclosure. Figure 6As shown, the device includes: a first determination module 10, used to determine the current frequency and current peak value of the alternating current input into the battery; an acquisition module 20, used to simultaneously acquire the instantaneous current value and the instantaneous voltage value in the battery; a second determination module 30, used to determine the target phase difference according to the current frequency and the target relationship function, the target phase difference being the phase difference between the current waveform of the alternating current input into the battery and the voltage waveform generated in the battery, the target relationship function being a pre-set relationship function representing the corresponding relationship between the current frequency and the target phase difference; a measurement module 40, used to determine the voltage peak value of the voltage waveform according to the instantaneous current value of the battery, the current frequency, the current peak value, the instantaneous voltage value of the battery and the target phase difference, and use the voltage peak value as the measurement voltage.

[0094] In a possible implementation, the device further includes: an acquisition module for acquiring battery specifications, wherein the battery specifications include at least battery materials; and a third determination module for determining a relationship function corresponding to the battery specifications as the target relationship function.

[0095] In a possible implementation manner, the current frequency of the alternating current input into the battery is greater than a preset frequency threshold, wherein when the current frequency is greater than the preset frequency threshold, the battery exhibits an inductive reactance characteristic.

[0096] In one possible implementation, the target relationship function is determined by the following method: constructing an equivalent circuit model of the battery; obtaining model parameters in the equivalent circuit model by testing a first battery model, wherein the first battery model is an actual battery that is identical to the battery and is used for testing; constructing a second battery model according to the model parameters, wherein the second battery model is a digital simulation battery that is identical to the battery; inputting simulated current waveforms of different current frequencies into the second battery model, respectively, to obtain simulated voltage waveforms corresponding to the outputs of the second battery model, and determining the target relationship function based on the phase difference between each simulated current waveform and its corresponding simulated voltage waveform, and the current peak value of each simulated current waveform.

[0097] In a possible implementation, the equivalent circuit model includes a first polarization resistor, a first polarization capacitor, a second polarization resistor, a second polarization capacitor, an inductor resistor, an inductor, and an ohmic internal resistance. The first polarization resistor and the first polarization capacitor are connected in parallel and then connected in series with the ohmic internal resistance. The second polarization resistor and the second polarization capacitor are connected in parallel and then also connected in series with the ohmic internal resistance. The inductor resistor and the inductor are connected in parallel and then also connected in series with the ohmic internal resistance.

[0098] In one possible embodiment, the tests performed on the first battery model include: a hybrid power pulse capability characteristic HPPC test and an electrochemical impedance spectroscopy EIS test, wherein the hybrid power pulse capability characteristic HPPC test is used to detect the values ​​of the ohmic internal resistance, the first polarization resistance, the second polarization resistance, the first polarization capacitance and the second polarization capacitance, and the electrochemical impedance spectroscopy EIS test is used to detect the value of the inductance; the value of the inductor resistance is calculated based on the detected values ​​of the ohmic internal resistance, the first polarization resistance, the second polarization resistance, the first polarization capacitance, the second polarization capacitance and the inductance.

[0099] In a possible implementation manner, the inductor resistance is calculated according to the following formula:

[0100]

[0101] Wherein, R1 is the first polarization resistor, R2 is the second polarization resistor, C1 is the first polarization capacitor, C2 is the second polarization capacitor, R3 is the inductor resistor, L is the inductor, R0 is the ohmic internal resistance, I rms is the effective value of the current in the first battery model, ΔUt is the peak voltage in the first battery model, f is the current or voltage fluctuation frequency in the first battery model, and the effective value of the current ΔUt, the peak voltage I rms , the frequency f is a known value during the test.

[0102] In a possible implementation manner, the value of the inductance obtained by the electrochemical impedance spectroscopy (EIS) test is the value of the inductance when the current frequency of the simulated current waveform is at a maximum value.

[0103] In a possible implementation, the method further includes: when the measured voltage exceeds a voltage threshold range corresponding to the battery, adjusting the current frequency and / or the current peak of the alternating current input into the battery so as to keep the battery voltage within the voltage threshold range.

[0104] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0105] In another exemplary embodiment, a computer-readable storage medium including program instructions is further provided. When the program instructions are executed by a processor, the steps of the above-mentioned battery voltage determination method are implemented.

[0106] In another exemplary embodiment, a computer program product is further provided. The computer program product includes a computer program executable by a programmable device. The computer program has a code portion for executing the above-mentioned battery voltage determination method when executed by the programmable device.

[0107] The present disclosure also provides a vehicle, comprising the battery voltage measuring device described above.

[0108] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0109] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0110] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for measuring battery voltage, characterized in that: The method comprises: Determine the current frequency and current peak value of the alternating current input into the battery; Simultaneously collecting the instantaneous current value and the instantaneous voltage value in the battery; determining a target phase difference according to the current frequency and a target relationship function, wherein the target phase difference is a phase difference between a current waveform of the alternating current input into the battery and a voltage waveform generated in the battery, and the target relationship function is a pre-set relationship function representing a corresponding relationship between the current frequency and the target phase difference; The voltage peak value of the voltage waveform is determined based on the battery instantaneous current value, the current frequency, the current peak value, the battery instantaneous voltage value, and the target phase difference, and the voltage peak value is used as the measurement voltage.

2. The method according to claim 1, characterized in that The method further comprises: Obtaining battery specifications of the battery, wherein the battery specifications at least include battery materials; A relationship function corresponding to the battery specification is determined as the target relationship function.

3. The method according to claim 1, characterized in that The current frequency of the alternating current input into the battery is greater than a preset frequency threshold, Wherein, when the current frequency is greater than the preset frequency threshold, the battery exhibits an inductive reactance characteristic.

4. The method according to claim 1, characterized in that: The target relationship function is determined by the following method: constructing an equivalent circuit model of the battery; The model parameters in the equivalent circuit model are obtained by testing a first battery model, wherein the first battery model is an actual battery that is the same as the battery and is used for testing; Constructing a second battery model according to the model parameters, wherein the second battery model is a digital simulation battery identical to the battery; The simulated current waveforms of different current frequencies are respectively input into the second battery model to obtain the simulated voltage waveforms corresponding to the output of the second battery model, and the target relationship function is determined according to the phase difference between each simulated current waveform and its corresponding simulated voltage waveform, and the current peak value of each simulated current waveform.

5. The method according to claim 4, characterized in that The equivalent circuit model includes a first polarization resistor, a first polarization capacitor, a second polarization resistor, a second polarization capacitor, an inductive resistor, an inductor, and an ohmic internal resistance. The first polarization resistor and the first polarization capacitor are connected in parallel and then connected in series with the ohmic internal resistor. The second polarization resistor and the second polarization capacitor are connected in parallel and then connected in series with the ohmic internal resistor. The inductive resistor and the inductor are connected in parallel and then connected in series with the ohmic internal resistor.

6. The method according to claim 5, characterized in that The tests performed on the first battery model include: a hybrid power pulse capability characteristic HPPC test and an electrochemical impedance spectroscopy EIS test, wherein: The hybrid power pulse capability characteristic HPPC test is used to detect the values ​​of the ohmic internal resistance, the first polarization resistance, the second polarization resistance, the first polarization capacitance and the second polarization capacitance, and the electrochemical impedance spectroscopy EIS test is used to detect the value of the inductance; The value of the inductor resistance is calculated based on the detected values ​​of the ohmic internal resistance, the first polarization resistance, the second polarization resistance, the first polarization capacitance, the second polarization capacitance and the inductance.

7. The method according to claim 6, characterized in that The inductor resistance is calculated according to the following formula: Wherein, R1 is the first polarization resistor, R2 is the second polarization resistor, C1 is the first polarization capacitor, C2 is the second polarization capacitor, R3 is the inductor resistor, L is the inductor, R0 is the ohmic internal resistance, I rms is the effective value of the current in the first battery model, ΔUt is the peak voltage in the first battery model, f is the current or voltage fluctuation frequency in the first battery model, and the effective value of the current ΔUt, the peak voltage I rms , the frequency f is a known value during the test.

8. The method according to claim 6, characterized in that The value of the inductance obtained through the electrochemical impedance spectroscopy (EIS) test is the value of the inductance when the current frequency of the simulated current waveform is at a maximum value.

9. The method according to claim 1, characterized in that: The method further comprises: When the measured voltage exceeds a voltage threshold range corresponding to the battery, the current frequency and / or the current peak value of the alternating current input into the battery is adjusted to keep the battery voltage within the voltage threshold range.

10. A battery voltage measuring device, characterized in that: The device comprises: A first determination module is used to determine the current frequency and current peak value of the alternating current input into the battery; A collection module, used for simultaneously collecting the instantaneous current value and the instantaneous voltage value in the battery; A second determination module is used to determine a target phase difference according to the current frequency and a target relationship function, wherein the target phase difference is a phase difference between a current waveform of the alternating current input into the battery and a voltage waveform generated in the battery, and the target relationship function is a preset relationship function representing a corresponding relationship between the current frequency and the target phase difference; The measuring module is used to determine the voltage peak value of the voltage waveform according to the instantaneous current value of the battery, the current frequency, the current peak value, the instantaneous voltage value of the battery and the target phase difference, and use the voltage peak value as the measuring voltage.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method described in any one of claims 1 to 9 are implemented.

12. A vehicle, characterized in that: A battery voltage measuring device comprising the battery voltage measuring device according to claim 10.

Images