Lithium ion battery pulse heating maximum heating power calculation method

Abstract

The invention provides a lithium ion battery pulse heating maximum heating power calculation method, and the method comprises the steps: obtaining an impedance test result of a lithium ion battery under a target test condition and a balance potential of a negative electrode to lithium, and the target test condition comprises a target battery temperature and a target electric quantity state; determining related parameters of the lithium ion battery according to an impedance test result; according to the relevant parameters and the equilibrium potential, determining the maximum current value of the pulse current of the lithium ion battery under the condition of no lithium precipitation and the impedance real part of the equivalent circuit diagram corresponding to the lithium ion battery; and calculating the maximum heating power of the lithium ion battery during pulse heating according to the current maximum value and the impedance real part. By implementing the method disclosed by the invention, the pulse heating strategy can be optimized to a great extent, and the heating rate is improved while the safety performance of the lithium battery is ensured.

Description

Technical Field

[0001] The present disclosure relates to the technical field of battery management, and in particular to a method for calculating the maximum heating power of pulse heating of a lithium-ion battery. Background Art

[0002] The performance of lithium-ion batteries directly impacts the range, safety, and reliability of electric vehicles. In low-temperature environments, lithium-ion batteries experience deteriorating power characteristics, reduced cycle life, and lower available capacity. Furthermore, they face challenges such as difficulty charging at low temperatures and the tendency for lithium deposition during charging. These factors hinder the development of electric vehicles. Low-temperature heating technology is a core technology in battery thermal management systems and is crucial for mitigating the performance degradation of power batteries in low-temperature environments. Low-temperature heating methods are primarily categorized into two types: external heating and internal heating. External heating utilizes a heat source external to the battery pack, such as thermal fluids, phase change materials, and electric heating elements, to heat the battery pack through convection or conduction. However, external heating methods suffer from long heat transfer paths, high heat losses, slow battery temperature rise rates, and poor temperature uniformity. Compared to external heating, internal heating utilizes heat generated by the battery's internal impedance to heat the battery, offering high energy efficiency, excellent temperature uniformity, and significantly reduced heating system complexity and cost. Within internal heating methods, pulse heating heats the battery by applying a pulsed excitation. This method offers advantages such as high heating rates, excellent temperature uniformity, and a simple system structure, and holds promising prospects for development.

[0003] In related technologies, when pulse heating is used, the balance between heating rate, battery life and system energy consumption cannot be guaranteed, so the pulse heating strategy needs to be further optimized. Summary of the Invention

[0004] The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the purpose of the present disclosure is to propose a method, device, computer equipment and storage medium for calculating the maximum heating power of lithium-ion battery pulse heating, which can optimize the pulse heating strategy to a large extent and improve the heating rate while ensuring the safety performance of the lithium battery.

[0006] To achieve the above objectives, the method for calculating the maximum heating power of a lithium-ion battery pulse heating proposed in the first embodiment of the present disclosure includes:

[0007] Obtaining impedance test results and a negative electrode-to-lithium equilibrium potential of a lithium-ion battery under target test conditions, wherein the target test conditions include a target battery temperature and a target state of charge;

[0008] Determining relevant parameters of the lithium-ion battery according to the impedance test results;

[0009] Determining, based on the relevant parameters and the equilibrium potential, a maximum current of the pulse current of the lithium ion battery under a non-lithium deposition condition and a real part of the impedance of the corresponding equivalent circuit diagram of the lithium ion battery;

[0010] The maximum heating power of the lithium-ion battery during pulse heating is calculated according to the maximum current value and the real part of the impedance.

[0011] To achieve the above-mentioned purpose, a device for calculating the maximum heating power of a lithium-ion battery pulse heating is provided in a second embodiment of the present disclosure, comprising:

[0012] An acquisition module is used to obtain the impedance test results of the lithium-ion battery under target test conditions and the equilibrium potential of the negative electrode to lithium, wherein the target test conditions include a target battery temperature and a target state of charge;

[0013] A first determining module, configured to determine relevant parameters of the lithium-ion battery according to the impedance test result;

[0014] a second determining module, configured to determine, based on the relevant parameters and the equilibrium potential, a maximum current of the pulse current of the lithium ion battery under a non-lithium deposition condition and a real part of the impedance of an equivalent circuit diagram corresponding to the lithium ion battery;

[0015] A calculation module is used to calculate the maximum heating power of the lithium-ion battery during pulse heating according to the maximum current and the real part of the impedance.

[0016] The computer device proposed in the third embodiment of the present disclosure includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the method for calculating the maximum heating power of pulse heating of a lithium-ion battery proposed in the first embodiment of the present disclosure is implemented.

[0017] The fourth embodiment of the present disclosure proposes a non-temporary computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the method for calculating the maximum heating power of pulse heating of a lithium-ion battery proposed in the first embodiment of the present disclosure is implemented.

[0018] The fifth embodiment of the present disclosure proposes a computer program product. When the instructions in the computer program product are executed by a processor, the method for calculating the maximum heating power of pulse heating of a lithium-ion battery proposed in the first embodiment of the present disclosure is executed.

[0019] The present disclosure provides a method, device, computer equipment, and storage medium for calculating the maximum heating power of a lithium-ion battery during pulse heating. The method obtains the impedance test results of a lithium-ion battery under target test conditions and the equilibrium potential of the negative electrode to lithium, wherein the target test conditions include a target battery temperature and a target state of charge; determines the relevant parameters of the lithium-ion battery based on the impedance test results; determines the maximum current of the pulse current of the lithium-ion battery under non-lithium precipitation conditions and the real part of the impedance of the corresponding equivalent circuit diagram of the lithium-ion battery based on the relevant parameters and the equilibrium potential; and calculates the maximum heating power of the lithium-ion battery during pulse heating based on the maximum current and the real part of the impedance. This method can significantly optimize the pulse heating strategy and improve the heating rate while ensuring the safety performance of the lithium battery.

[0020] Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present disclosure will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0022] Figure 1 This is a flow chart of a method for calculating the maximum heating power of a lithium-ion battery pulse heating according to an embodiment of the present disclosure;

[0023] Figure 2 1 is a flow chart of a method for calculating the maximum heating power of a lithium-ion battery pulse heating according to another embodiment of the present disclosure;

[0024] Figure 3 This is a schematic diagram of the pulse heating principle of a lithium battery proposed in the present disclosure;

[0025] Figure 4 is an equivalent circuit diagram of a lithium battery according to the present disclosure;

[0026] Figure 5 is a schematic diagram of the impedance spectrum of a lithium battery proposed in the present disclosure;

[0027] Figure 6 This is a schematic diagram of the structure of a device for calculating the maximum heating power of a lithium-ion battery pulse heating according to an embodiment of the present disclosure;

[0028] Figure 7 A block diagram of an exemplary computer device suitable for implementing embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0029] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present disclosure and are not to be construed as limiting the present disclosure. On the contrary, the embodiments of the present disclosure include all variations, modifications, and equivalents that fall within the spirit and scope of the appended claims.

[0030] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.) and signals involved in this disclosure are all authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with the relevant laws, regulations and standards of relevant countries and regions.

[0031] Figure 1 This is a flow chart of a method for calculating the maximum heating power of pulse heating of a lithium-ion battery proposed in one embodiment of the present disclosure.

[0032] Among them, it should be noted that the executor of the lithium-ion battery pulse heating maximum heating power calculation method of this embodiment is a lithium-ion battery pulse heating maximum heating power calculation device, which can be implemented by software and / or hardware. The device can be configured in a computer device, and the computer device can include but is not limited to a terminal, a server end, etc. For example, the terminal can be a mobile phone, a handheld computer, etc.

[0033] like Figure 1 As shown, the method for calculating the maximum heating power of the lithium-ion battery pulse heating includes:

[0034] S101: Obtaining impedance test results of a lithium-ion battery under target test conditions and an equilibrium potential of the negative electrode to lithium, wherein the target test conditions include a target battery temperature and a target state of charge.

[0035] The target test conditions refer to the impedance test experimental conditions configured based on the battery pulse heating requirements of the lithium-ion battery in the embodiment of the present disclosure.

[0036] The target battery temperature refers to the battery temperature of the lithium-ion battery during the impedance test.

[0037] The target state of charge may refer to the battery charge of the lithium-ion battery during impedance testing.

[0038] In the embodiment of the present disclosure, the specific values ​​of the target battery temperature and the target state of charge can be flexibly configured according to the application scenario, and there is no limitation on this.

[0039] Among them, the impedance test results refer to the results obtained through experimental analysis of the internal impedance characteristics of the battery under different working conditions.

[0040] In the embodiment of the present disclosure, when obtaining the impedance test result of the lithium-ion battery under target test conditions, an EIS impedance test may be performed on the lithium-ion battery to obtain the impedance test result.

[0041] Among them, the equilibrium potential of the negative electrode to lithium is used to describe the equilibrium potential of the negative electrode material relative to the metal lithium reference electrode (Li / Li + ) voltage.

[0042] Optionally, in some embodiments, the target battery temperature ranges from -30°C to 10°C; and the target state of charge ranges from 0 to 100%.

[0043] Optionally, in some embodiments, the lithium-ion battery is any one of the following battery types: lithium iron phosphate battery; lithium cobalt oxide battery; lithium manganese oxide battery; NCM ternary lithium battery; NCA ternary lithium battery; lithium iron manganese phosphate battery.

[0044] Optionally, in some embodiments, the lithium-ion battery is any one of the following battery types: a soft-pack battery; a laminated square-shell battery; or a wound square-shell battery.

[0045] The present disclosure obtains the impedance test results of the lithium-ion battery under the target test conditions and the equilibrium potential of the negative electrode to lithium, which can provide reliable data support for the subsequent calculation of the maximum heating power of the lithium-ion battery during pulse heating.

[0046] S102: Determine relevant parameters of the lithium-ion battery according to the impedance test result.

[0047] The relevant parameters may refer to parameters related to the lithium-ion battery determined based on the impedance test results in the embodiment of the present disclosure. For example, they may include resistance parameters and impedance parameters in the lithium-ion battery.

[0048] In the embodiment of the present disclosure, when determining relevant parameters of the lithium-ion battery based on the impedance test results, the impedance test results may be fitted to obtain appropriate relevant parameters.

[0049] That is to say, in the embodiment of the present disclosure, after obtaining the impedance test results of the lithium-ion battery under the target test conditions and the equilibrium potential of the negative electrode to lithium, the relevant parameters of the lithium-ion battery can be determined based on the impedance test results, thereby providing reliable data support for the subsequent determination of the maximum current of the pulse current of the lithium-ion battery under non-lithium precipitation conditions, and the real part of the impedance of the corresponding equivalent circuit diagram of the lithium-ion battery.

[0050] S103: Determine the maximum current of the pulse current of the lithium-ion battery without lithium deposition and the real part of the impedance of the corresponding equivalent circuit diagram of the lithium-ion battery based on relevant parameters and the equilibrium potential.

[0051] The maximum current value of the pulse current of the lithium-ion battery without lithium deposition may refer to the maximum value that the pulse current can reach while ensuring that lithium deposition does not occur during the process of heating the lithium-ion battery based on the pulse current.

[0052] The real part of the impedance of a lithium-ion battery's equivalent circuit diagram represents the battery's resistive response to an AC signal within the equivalent circuit model, representing the portion of energy dissipated as heat. This quantitative indicator of resistive behavior in the equivalent circuit is determined by ohmic resistance, charge transfer resistance, and diffusion impedance.

[0053] In the embodiment of the present disclosure, when determining the maximum current of the pulse current of the lithium-ion battery under the condition of no lithium precipitation and the real part of the impedance of the equivalent circuit diagram corresponding to the lithium-ion battery based on the relevant parameters and the equilibrium potential, the relevant parameters and the equilibrium potential can be input into a pre-trained machine learning model to obtain the corresponding maximum current and real part of the impedance. Alternatively, a third-party device can determine the maximum current of the pulse current of the lithium-ion battery under the condition of no lithium precipitation and the real part of the impedance of the equivalent circuit diagram corresponding to the lithium-ion battery based on the relevant parameters and the equilibrium potential, and there is no limitation on this.

[0054] Optionally, in some embodiments, the waveform type of the pulse current may be determined; when the waveform type indicates that the pulse current is not a sinusoidal pulse current, the pulse current may be transformed into a form in which multiple sinusoidal wave currents are superimposed.

[0055] It is understandable that electrochemical impedance spectroscopy (EIS) assumes that the battery system is linear under small perturbations (the voltage response is proportional to the current). The sine wave is the characteristic function of a linear system (a sine wave is input and a sine wave of the same frequency is output, with only the amplitude and phase changing). However, the pulse current contains a broadband component, and its response may excite nonlinear effects, complicating the impedance analysis. Non-sinusoidal signals (such as square waves and pulses) will produce higher-order harmonics, which may induce additional voltage responses in nonlinear systems and interfere with the measurement of the fundamental frequency impedance. Therefore, the pulse current is uniformly converted into a sine wave in order to meet the frequency domain definition of impedance, maintain the rationality of the linear system assumption, and be compatible with the standard EIS method.

[0056] In the embodiment of the present disclosure, when the maximum current of the pulse current of the lithium-ion battery under the condition of no lithium precipitation and the real part of the impedance of the corresponding equivalent circuit diagram of the lithium-ion battery are determined based on relevant parameters and equilibrium potential, reliable data support can be provided for the subsequent calculation of the maximum heating power of the lithium-ion battery during pulse heating.

[0057] S104: Calculate the maximum heating power of the lithium-ion battery during pulse heating based on the maximum current and the real part of the impedance.

[0058] Among them, the maximum heating power refers to the maximum power of pulse heating of the lithium-ion battery under the premise of ensuring system safety.

[0059] For example, in the embodiment of the present disclosure, according to the maximum current I ac and the real part of the impedance Z Re , the calculation of the maximum heating power Q of lithium-ion batteries during pulse heating can be based on the following formula:

[0060]

[0061] In this embodiment, the impedance test results of a lithium-ion battery under target test conditions, including a target battery temperature and a target state of charge, and the equilibrium potential of the negative electrode relative to lithium are obtained. Based on the impedance test results, relevant parameters of the lithium-ion battery are determined. Based on the relevant parameters and the equilibrium potential, the maximum current of the pulse current of the lithium-ion battery under non-lithium deposition conditions and the real impedance part of the corresponding equivalent circuit diagram of the lithium-ion battery are determined. Based on the maximum current and the real impedance part, the maximum heating power of the lithium-ion battery during pulse heating is calculated. This allows for significant optimization of the pulse heating strategy, improving the heating rate while ensuring the safety of the lithium-ion battery.

[0062] Figure 2 It is a flow chart of a method for calculating the maximum heating power of pulse heating of a lithium-ion battery proposed in another embodiment of the present disclosure.

[0063] like Figure 2 As shown, the method for calculating the maximum heating power of the lithium-ion battery pulse heating includes:

[0064] S201: Obtaining impedance test results of a lithium-ion battery under target test conditions and an equilibrium potential of the negative electrode to lithium, wherein the target test conditions include a target battery temperature and a target state of charge.

[0065] S202: Determine relevant parameters of the lithium-ion battery based on the impedance test results, where the frequency of the pulse current ranges from 1 Hz to 1 kHz, and the relevant parameters include: charge transfer resistance, a first phase angle index and a first modulus of a double-layer constant phase angle element, ohmic resistance, solid electrolyte interface resistance, and a second phase angle index and a second modulus of a solid electrolyte interface constant phase angle element.

[0066] The description of S201 and S202 can be found in the above embodiments, which will not be repeated here.

[0067] S203: Determine, based on a frequency range of the pulse current, that the overpotential of the lithium-ion battery is equal to the electrochemical polarization voltage, wherein the sum of the overpotential and the equilibrium potential is equal to the negative electrode potential of the lithium-ion battery.

[0068] It can be understood that the overpotential is equal to the voltage generated by polarization, that is, the electrochemical polarization voltage and the concentration polarization voltage. When the pulse is selected in the range of 1-1000Hz, the concentration polarization can be ignored. Therefore, the overpotential is equal to the electrochemical polarization voltage U ct , when the battery is charging the overpotential is negative.

[0069] S204: Determine a comparison result between the electrochemical polarization voltage and the equilibrium potential based on a theoretical safety boundary condition in which no lithium is deposited at the negative electrode of the battery.

[0070] Among them, the theoretical safety boundary condition for no lithium deposition at the negative electrode of the battery can be expressed as follows:

[0071] Negative electrode potential φ negative > 0 V vsLi / Li+

[0072] φnegative=U e (equilibrium potential) + ηn (overpotential)

[0073] And because of the above known conclusion: overpotential is equal to electrochemical polarization voltage U ct , when the battery is charged, the overpotential is negative. The comparison result of the electrochemical polarization voltage and the equilibrium potential can be determined as the electrochemical polarization voltage U ct Less than or equal to the equilibrium potential U e . That is: U e -U ct >0V vsLi / Li+.

[0074] S205: Calculate and determine the polarization impedance of the lithium-ion battery based on the charge transfer resistance, the first phase angle index, and the first modulus value, wherein the product of the polarization impedance and the pulse current value is equal to the electrochemical polarization voltage.

[0075] Among them, the charge transfer resistance R ct , which can reflect the resistance of the charge transfer reaction on the electrode surface to overcome the activation energy barrier.

[0076] Among them, the first phase angle index n dl , can refer to the phase angle index of the double layer constant phase angle element.

[0077] Among them, the first modulus value Q dl , which can refer to the modulus of the double-layer constant phase angle element.

[0078] Among them, polarization impedance Z3 (Polarization Impedance) is the total impedance generated by electrochemical polarization, concentration polarization, and ohmic polarization during the charge and discharge process of the battery, reflecting the resistance of the internal dynamic process of the battery. It is the main reason why the battery voltage lags behind the equilibrium potential (i.e., the charge and discharge platform voltage deviates). The magnitude of polarization impedance directly affects the power performance, energy efficiency, and cycle life of the battery. For example, the calculation formula of polarization impedance Z3 is as follows:

[0079]

[0080] Among them, neg represents the negative electrode of the battery.

[0081] S206: Determine the maximum current value of the pulse current of the lithium-ion battery without lithium deposition based on the equilibrium potential, the polarization impedance, and the comparison result.

[0082] It can be understood that the product of polarization impedance and pulse current is equal to the electrochemical polarization voltage U ct Therefore, in the embodiment of the present disclosure, the maximum current of the pulse current of the lithium-ion battery without lithium precipitation can be determined based on the equilibrium potential, polarization impedance and comparison results. For example, the maximum current I ac The calculation expression is as follows:

[0083]

[0084] That is to say, in the embodiment of the present disclosure, the frequency range of the pulse current is 1Hz-1kHz, and the relevant parameters include: charge transfer resistance and the first phase angle index and the first modulus of the double-layer constant phase angle element; wherein, the maximum current is determined based on the following method: according to the frequency range of the pulse current, the overpotential of the lithium-ion battery is determined to be equal to the electrochemical polarization voltage, wherein the sum of the overpotential and the equilibrium potential is equal to the negative electrode potential of the lithium-ion battery; according to the theoretical safety boundary condition of no lithium precipitation at the negative electrode of the battery, the comparison result of the electrochemical polarization voltage and the equilibrium potential is determined; according to the charge transfer resistance, the first phase angle index and the first modulus, the polarization impedance of the lithium-ion battery is calculated and determined, wherein the product of the polarization impedance and the pulse current value is equal to the electrochemical polarization voltage; according to the equilibrium potential, polarization impedance and the comparison result, the maximum current of the pulse current of the lithium-ion battery under the condition of no lithium precipitation is determined. Thus, the reliability and practicality of the obtained current maximum value can be effectively improved by combining the relevant parameters.

[0085] S207: Determine a first adjustment value according to the charge transfer resistance, the first phase angle index, and the first modulus.

[0086] The first adjustment value may be used to adjust the charge transfer resistance when calculating the real part of the impedance of the equivalent circuit diagram corresponding to the lithium-ion battery.

[0087] S208: Calculate and determine a second adjustment value according to the solid electrolyte interface resistance, the second phase angle index, and the second modulus.

[0088] The second adjustment value can be used to adjust the solid electrolyte interface resistance when calculating the real part of the impedance of the equivalent circuit diagram corresponding to the lithium-ion battery.

[0089] S209: Determine a first product value of the charge transfer resistance and the first adjustment value, and a second product value of the solid electrolyte interface resistance and the second adjustment value.

[0090] That is, after determining the first adjustment value and the second adjustment value in the embodiment of the present disclosure, the first product value of the charge transfer resistance and the first adjustment value, and the second product value of the solid electrolyte interface resistance and the second adjustment value can be determined, thereby providing data support for the subsequent calculation of the real part of the impedance.

[0091] S210: Calculate the sum of the ohmic resistance, the first product value, and the second product value as the real part of the impedance.

[0092] That is, in the disclosed embodiment, the relevant parameters also include: ohmic resistance, solid electrolyte interface resistance, and the second phase angle index and second modulus of the solid electrolyte interface constant phase angle element; wherein the real part of the impedance is determined based on the following method: determining a first adjustment value based on the charge transfer resistance, the first phase angle index, and the first modulus; calculating and determining a second adjustment value based on the solid electrolyte interface resistance, the second phase angle index, and the second modulus; determining a first product value of the charge transfer resistance and the first adjustment value, and a second product value of the solid electrolyte interface resistance and the second adjustment value; and calculating the sum of the ohmic resistance, the first product value, and the second product value as the real part of the impedance. Thus, the charge transfer resistance and the solid electrolyte interface resistance can be reasonably adjusted based on the first adjustment value and the second adjustment value, thereby ensuring the reliability of the obtained real part of the impedance.

[0093] For example, in the embodiment of the present disclosure, according to the charge transfer resistance R ct , the first phase angle index n dl and the first modulus Q dl , determine the first adjustment value; according to the solid electrolyte interface resistance R SEI , the second phase angle index n SEI and the second modulus Q SEI , calculate and determine the second adjustment value; determine the charge transfer resistance R ct and the first product value of the first adjustment value, and the solid electrolyte interface resistance R SEI Calculate the sum of the ohmic resistance, the first product value and the second product value as the real part of the impedance Z Re, can be based on the following formula:

[0094]

[0095] S211: Calculate the maximum heating power of the lithium-ion battery during pulse heating based on the maximum current and the real part of the impedance.

[0096] The description of S211 can be found in the above embodiment and will not be repeated here.

[0097] In this embodiment, the overpotential of the lithium-ion battery is determined to be equal to the electrochemical polarization voltage according to the frequency range of the pulse current, wherein the sum of the overpotential and the equilibrium potential is equal to the negative electrode potential of the lithium-ion battery; according to the theoretical safety boundary condition of no lithium deposition at the negative electrode of the battery, the comparison result of the electrochemical polarization voltage and the equilibrium potential is determined; according to the charge transfer resistance, the first phase angle index and the first modulus, the polarization impedance of the lithium-ion battery is calculated and determined, wherein the product of the polarization impedance and the pulse current value is equal to the electrochemical polarization voltage; according to the equilibrium potential, the polarization impedance and the comparison result, the maximum current of the pulse current of the lithium-ion battery under the condition of no lithium deposition is determined. Thus, the reliability and practicality of the obtained maximum current value can be effectively improved by combining relevant parameters. By determining the first adjustment value according to the charge transfer resistance, the first phase angle index and the first modulus; calculating and determining the second adjustment value according to the solid electrolyte interface resistance, the second phase angle index and the second modulus; determining the first product value of the charge transfer resistance and the first adjustment value, and the second product value of the solid electrolyte interface resistance and the second adjustment value; calculating the sum of the ohmic resistance, the first product value and the second product value as the real part of the impedance. Therefore, reasonable adjustment of the charge transfer resistance and the solid electrolyte interface resistance can be achieved based on the first adjustment value and the second adjustment value, thereby ensuring the reliability of the obtained real part of the impedance.

[0098] In summary of the above embodiments, the first aspect of the present disclosure provides a calculation principle of the lithium deposition boundary and the maximum heating power of a lithium-ion battery under pulse heating. Figure 3 As shown, Figure 3 This is a schematic diagram of the pulse heating principle of lithium batteries proposed in the present disclosure. When switches K1 and K2 are closed, the battery charges the inductor L. When switches K1 and K2 are opened, the inductor, diode, and battery form a loop to charge the battery. The switching frequency of the switches is controlled to form a high-frequency positive / direction current to pulse charge / discharge the battery. When the current passes through the internal resistance of the lithium battery, it generates heat, thereby heating the lithium battery. Figure 4 As shown, Figure 4 This is an equivalent circuit diagram of a lithium battery proposed in the present disclosure. In the equivalent circuit model, the internal impedance of the battery is divided into three parts: Z1, Z2, and Z3, which represent the battery's ohmic impedance, SEI film impedance, and polarization impedance, respectively. Reis the real part of the impedance of the equivalent circuit diagram, including ohmic resistance (R0), solid electrolyte interface (SEI) resistance (R SEI ), charge transfer resistance R ct , Q SEI and Q dl denote the modulus of the constant phase element (CPE) of the SEI and the electric double layer, respectively.

[0099] In the second aspect, this patent provides a method for calculating the lithium deposition boundary and maximum heating power of a lithium-ion battery under pulse heating. The specific steps include:

[0100] 1) EIS impedance test of lithium-ion batteries at different SOC and different temperatures;

[0101] 2) Fitting the EIS impedance test results to obtain the appropriate ohmic resistance (R0), solid electrolyte interface (SEI) resistance (R SEI ), charge transfer resistance R ct , the second modulus Q SEI , the second phase angle index n SEI , the first modulus Q dl and the first phase angle index n dl ;

[0102] 3) Test the equilibrium potential U of the negative electrode to lithium at different SOC and different temperatures e ;

[0103] 4) Determine the type of pulse current, whether it is sinusoidal, triangular, square or trapezoidal;

[0104] 5) The triangular, square and trapezoidal pulse currents are transformed into multiple sine waves through Fourier transformation:

[0105] Sinusoidal pulse current is: i(t) = I ac sinωt;

[0106] The square pulse current can be converted into 128 sine waves through Fourier transformation:

[0107]

[0108] The triangular pulse current can be converted into 128 sine waves through Fourier transformation:

[0109]

[0110] The trapezoidal pulse current can be transformed into 128 sine waves by Fourier transformation:

[0111]

[0112] 6) Calculate the pulse current I at the lithium deposition boundary according to the following formula: ac :

[0113] Ue-Uct>0V vsLi / Li+;

[0114]

[0115] 7) Calculate the maximum power of battery pulse heating according to the following formula:

[0116]

[0117] For example, in combination with the above embodiment, the present disclosure provides the following steps for calculating the lithium deposition boundary and maximum heating power of a 135Ah prismatic lithium iron phosphate battery under pulse heating:

[0118] 1) Test the EIS impedance spectrum of 135Ah square shell lithium iron phosphate battery at -20℃ and 80% SOC condition (such as Figure 5 As shown in the point, Figure 5 is a schematic diagram of the impedance spectrum of a lithium battery proposed in the present disclosure);

[0119] 2) EIS impedance test results fitting (such as Figure 5 The appropriate resistances including ohmic resistance (R0), solid electrolyte interface (SEI) resistance (R SEI ), charge transfer resistance R ct , Q SEI 、n SEI , Q dl and n dl ;

[0120] 3) Test the equilibrium potential U of the negative electrode to lithium at 80% SOC at -20°C e , is 0.09387V;

[0121] 4) Make sure the pulse current used is a triangular wave current;

[0122] 5) The triangular pulse current is transformed into multiple sine waves through Fourier transformation;

[0123] 6) Based on the above formula, the pulse current I of the lithium deposition boundary under different pulse frequencies is calculated. ac ;

[0124] 7) Calculate the maximum power of battery pulse heating based on the above formula.

[0125] Figure 6 It is a structural schematic diagram of a device for calculating the maximum heating power of pulse heating of a lithium-ion battery proposed in one embodiment of the present disclosure.

[0126] like Figure 6As shown, the lithium-ion battery pulse heating maximum heating power calculation device 60 includes:

[0127] An acquisition module 601 is configured to acquire an impedance test result of a lithium-ion battery under target test conditions and an equilibrium potential of the negative electrode to lithium, wherein the target test conditions include a target battery temperature and a target state of charge;

[0128] A first determining module 602 is configured to determine relevant parameters of the lithium-ion battery according to the impedance test result;

[0129] A second determining module 603 is configured to determine the maximum current of the pulse current of the lithium-ion battery without lithium deposition, and the real part of the impedance of the corresponding equivalent circuit diagram of the lithium-ion battery based on relevant parameters and the equilibrium potential;

[0130] The calculation module 604 is used to calculate the maximum heating power of the lithium-ion battery during pulse heating according to the maximum current and the real part of the impedance.

[0131] It should be noted that the aforementioned explanation of the method for calculating the maximum heating power of pulse heating of a lithium-ion battery is also applicable to the device for calculating the maximum heating power of pulse heating of a lithium-ion battery in this embodiment, and will not be repeated here.

[0132] In this embodiment, the impedance test results of a lithium-ion battery under target test conditions, including a target battery temperature and a target state of charge, and the equilibrium potential of the negative electrode relative to lithium are obtained. Based on the impedance test results, relevant parameters of the lithium-ion battery are determined. Based on the relevant parameters and the equilibrium potential, the maximum current of the pulse current of the lithium-ion battery under non-lithium deposition conditions and the real impedance part of the corresponding equivalent circuit diagram of the lithium-ion battery are determined. Based on the maximum current and the real impedance part, the maximum heating power of the lithium-ion battery during pulse heating is calculated. This allows for significant optimization of the pulse heating strategy, improving the heating rate while ensuring the safety of the lithium-ion battery.

[0133] Figure 7 A block diagram of an exemplary computer device suitable for implementing embodiments of the present disclosure is shown. Figure 7 The computer device 12 shown is only an example and should not bring any limitation to the functionality and scope of use of the embodiments of the present disclosure.

[0134] like Figure 7 As shown, computer device 12 is implemented as a general-purpose computing device. Components of computer device 12 may include, but are not limited to, one or more processors or processing units 16, system memory 28, and a bus 18 that connects various system components (including system memory 28 and processing unit 16).

[0135] Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, or a local bus using any of a variety of bus architectures. Examples of such architectures include, but are not limited to, the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MAC) bus, the Enhanced ISA bus, the Video Electronics Standards Association (VESA) local bus, and the Peripheral Component Interconnection (PCI) bus.

[0136] The computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by the computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0137] The memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. The computer device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, the storage system 34 may be configured to read and write non-removable, non-volatile magnetic media ( Figure 7 Not shown, often called a "hard drive").

[0138] although Figure 7 Not shown, a disk drive for reading and writing to a removable non-volatile disk (e.g., a "floppy disk"), and an optical disk drive for reading and writing to a removable non-volatile optical disk (e.g., a Compact Disc Read Only Memory (hereinafter referred to as: CD-ROM), a Digital Video Disc Read Only Memory (hereinafter referred to as: DVD-ROM), or other optical media) may be provided. In these cases, each drive can be connected to the bus 18 via one or more data medium interfaces. The memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the various embodiments of the present disclosure.

[0139] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in memory 28. Such program modules 42 include, but are not limited to, an operating system, one or more application programs, other program modules, and program data, each of which, or some combination thereof, may include an implementation of a network environment. Program modules 42 generally implement the functions and / or methods of the embodiments described herein.

[0140] The computer device 12 can also communicate with one or more external devices 14 (e.g., a keyboard, pointing device, display 24, etc.), one or more devices that enable human interaction with the computer device 12, and / or any device that enables the computer device 12 to communicate with one or more other computing devices (e.g., a network card, a modem, etc.). This communication can occur via an input / output (I / O) interface 22. Furthermore, the computer device 12 can communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network such as the Internet) via a network adapter 20. As shown, the network adapter 20 communicates with the other modules of the computer device 12 via a bus 18. It should be understood that, although not shown, other hardware and / or software modules can be used in conjunction with the computer device 12, including but not limited to microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.

[0141] The processing unit 16 executes various functional applications and data processing by running the programs stored in the system memory 28, such as implementing the method for calculating the maximum heating power of pulse heating of a lithium-ion battery mentioned in the above embodiment.

[0142] In order to implement the above embodiments, the present disclosure also proposes a non-temporary computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, it implements the method for calculating the maximum heating power of lithium-ion battery pulse heating proposed in the above embodiments of the present disclosure.

[0143] In order to implement the above embodiments, the present disclosure also proposes a computer program product. When the instruction processor in the computer program product is executed, the method for calculating the maximum heating power of pulse heating of a lithium-ion battery proposed in the above embodiments of the present disclosure is executed.

[0144] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in this disclosure are in compliance with relevant laws and regulations and do not violate public order and good morals.

[0145] It is important to note that personal information collected from users should be used for legitimate and reasonable purposes and should not be shared or sold beyond these legitimate uses. Furthermore, such collection / sharing should be conducted only after receiving the user's informed consent, including but not limited to notifying the user to read the user agreement / user notice and sign an agreement / authorization that includes the relevant user information before using the feature. Furthermore, any necessary steps must be taken to safeguard and secure access to such personal information and ensure that others with access to personal information comply with its privacy policy and procedures.

[0146] This disclosure contemplates providing implementations that allow users to selectively block the use or access of personal information data. Specifically, this disclosure contemplates providing hardware and / or software to prevent or block access to such personal information data. Risks can be minimized by limiting data collection and deleting data once it is no longer needed. Furthermore, where applicable, such personal information can be de-identified to protect user privacy.

[0147] In the descriptions of the aforementioned embodiments, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are mutually inconsistent.

[0148] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0149] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present disclosure includes additional implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present disclosure belong.

[0150] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0151] It should be understood that various parts of the present disclosure can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0152] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0153] In addition, the functional units in the various embodiments of the present disclosure may be integrated into a single processing module, or each unit may exist physically separately, or two or more units may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or in the form of software functional modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

[0154] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. A person of ordinary skill in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A method for calculating the maximum heating power of a lithium-ion battery pulse heating, characterized in that: include: Obtaining impedance test results and a negative electrode-to-lithium equilibrium potential of a lithium-ion battery under target test conditions, wherein the target test conditions include a target battery temperature and a target state of charge; Determining relevant parameters of the lithium-ion battery according to the impedance test results; Determining, based on the relevant parameters and the equilibrium potential, a maximum current of the pulse current of the lithium ion battery under a non-lithium deposition condition and a real part of the impedance of the corresponding equivalent circuit diagram of the lithium ion battery; The maximum heating power of the lithium-ion battery during pulse heating is calculated according to the maximum current value and the real part of the impedance.

2. The method according to claim 1, wherein The frequency of the pulse current is in the range of 1 Hz to 1 kHz, and the related parameters include: charge transfer resistance and the first phase angle index and first modulus of the double-layer constant phase angle element; The maximum current is determined based on the following method: Determining, based on the frequency range of the pulse current, that the overpotential of the lithium-ion battery is equal to the electrochemical polarization voltage, wherein the sum of the overpotential and the equilibrium potential is equal to the negative electrode potential of the lithium-ion battery; Determining a comparison result between the electrochemical polarization voltage and the equilibrium potential based on a theoretical safety boundary condition in which no lithium is deposited at the negative electrode of the battery; Calculating and determining the polarization impedance of the lithium-ion battery based on the charge transfer resistance, the first phase angle index, and the first modulus, wherein the product of the polarization impedance and the pulse current value is equal to the electrochemical polarization voltage; The maximum current value of the pulse current of the lithium-ion battery without lithium deposition is determined according to the equilibrium potential, the polarization impedance and the comparison result.

3. The method according to claim 2, wherein The related parameters also include: ohmic resistance, solid electrolyte interface resistance, and a second phase angle index and a second modulus of a solid electrolyte interface constant phase angle element; The real part of the impedance is determined based on the following method: determining a first adjustment value according to the charge transfer resistance, the first phase angle index, and the first modulus; Calculating and determining a second adjustment value according to the solid electrolyte interface resistance, the second phase angle index, and the second modulus; determining a first product value of the charge transfer resistance and the first adjustment value, and a second product value of the solid electrolyte interface resistance and the second adjustment value; The sum of the ohmic resistance, the first product value, and the second product value is calculated as the real part of the impedance.

4. The method according to claim 1, wherein The method further comprises: determining a waveform type of the pulse current; When the waveform type indicates that the pulse current is not a sinusoidal pulse current, the pulse current is converted into a form in which a plurality of sinusoidal wave currents are superimposed.

5. The method according to claim 1, wherein in, The target battery temperature ranges from -30°C to 10°C. The target power state has a value range of 0-100%.

6. The method according to claim 1, wherein in, The lithium-ion battery is any of the following battery types: Lithium iron phosphate battery; Lithium cobalt oxide battery; Lithium manganese oxide battery; NCM ternary lithium battery; NCA ternary lithium battery; Lithium manganese iron phosphate battery.

7. The method according to claim 1, wherein in, The lithium-ion battery is any of the following battery types: soft pack battery; Laminated square shell battery; Wound square battery.

8. A device for calculating the maximum heating power of a lithium-ion battery pulse heating, characterized in that: include: An acquisition module is used to obtain the impedance test results of the lithium-ion battery under target test conditions and the equilibrium potential of the negative electrode to lithium, wherein the target test conditions include a target battery temperature and a target state of charge; A first determining module, configured to determine relevant parameters of the lithium-ion battery according to the impedance test result; a second determining module, configured to determine, based on the relevant parameters and the equilibrium potential, a maximum current of the pulse current of the lithium ion battery under a non-lithium deposition condition and a real part of the impedance of an equivalent circuit diagram corresponding to the lithium ion battery; A calculation module is used to calculate the maximum heating power of the lithium-ion battery during pulse heating according to the maximum current and the real part of the impedance.

9. A computer device, characterized in that: include: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium storing computer instructions, characterized in that: in, The computer instructions are used to cause the computer to execute the method according to any one of claims 1 to 7.

11. A computer program product, characterized in that The invention comprises a computer program which, when executed by a processor, implements the steps of the method according to any one of claims 1 to 7.

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