Battery current estimation method and device in failure mode of current acquisition circuit

Abstract

The invention discloses a battery current estimation method and device in a current acquisition circuit failure mode, and relates to the technical field of power batteries, and the method comprises the steps: obtaining the real-time charge quantity of a power battery after a control program detects that the current acquisition circuit of the power battery fails; acquiring the open-circuit voltage of the power battery based on the open-circuit voltage test data of the power battery and the real-time charge quantity; based on the use condition data of the power battery and the battery performance test data, obtaining an equivalent circuit model of the power battery; based on an equivalent circuit model and the open-circuit voltage, polarization partial voltage of the RC circuit is obtained; obtaining the current of a circuit where the power battery is located based on polarization partial voltage, the polarization resistance and the polarization capacitance; according to the method, when the current acquisition circuit of the power battery suddenly loses efficacy, the current flowing through the power battery can be quickly obtained with low cost.

Description

Technical Field

[0001] The present invention relates to a method for estimating battery current in a current acquisition circuit failure mode in the technical field of automotive power batteries, and in particular to a method for estimating battery current in a current acquisition circuit failure mode, and also to a battery current estimation device in a current acquisition circuit failure mode using the method. Background Art

[0002] As the market share of new energy vehicles gradually increases, the safety of battery packs has attracted more and more attention. The types of battery collection parameters include temperature, current and voltage. As one of the core safety parameters of the battery pack, current is usually collected by shunt current sensors and Hall current sensors. When the current sensor fails, the bus current cannot be collected normally, which in turn affects the software function and safety of the battery pack.

[0003] The current measure to deal with the failure of battery pack current sensors is to use redundant hardware design, that is, to add an additional set of backup current sensor collection. This type of solution is mainly hardware means and the hardware cost is relatively high.

[0004] Therefore, there is an urgent need for a method for quickly and inexpensively acquiring the current of a power battery when a current acquisition circuit of the power battery suddenly fails. Summary of the invention

[0005] In order to acquire the current of a power battery quickly and at low cost when a current acquisition circuit of the power battery suddenly fails, the present invention provides a method and device for estimating the battery current in a current acquisition circuit failure mode.

[0006] The present invention is implemented by the following technical scheme: a battery current estimation method under a current acquisition circuit failure mode, which comprises the following steps: when a current acquisition circuit failure of a power battery is detected, the real-time charge of the power battery is obtained; based on the open circuit voltage test data of the power battery and the real-time charge, the open circuit voltage of the power battery is obtained; based on the operating condition data of the power battery and the battery performance test data, the equivalent circuit model of the power battery is obtained; the equivalent circuit model includes an RC circuit composed of an ohmic internal resistance, a polarization resistor and a polarization capacitor, and a current source; based on the equivalent circuit model and the open circuit voltage, the polarization partial pressure of the RC circuit is obtained; based on the polarization partial pressure, the polarization resistor and the polarization capacitor, the total current of the circuit in which the power battery is located is obtained.

[0007] As a further improvement of the above scheme, the open circuit voltage of the power battery is obtained based on the open circuit voltage test data of the power battery and the real-time charge, which previously includes the following steps: obtaining the open circuit voltage test data of the power battery; taking the open circuit voltage as the dependent variable, the real-time charge as the first independent variable, and the real-time temperature of the power battery as the second independent variable; based on the open circuit voltage test data, obtaining a preset mapping relationship between the dependent variable, the first independent variable and the second independent variable.

[0008] As a further improvement of the above scheme, the open circuit voltage of the power battery is obtained based on the open circuit voltage test data of the power battery and the real-time charge amount, comprising the following steps: obtaining the real-time temperature of the power battery; substituting the real-time temperature and the current charge amount into the preset mapping relationship to obtain the open circuit voltage of the power battery.

[0009] As a further improvement of the above scheme, when the equivalent circuit model is a first-order RC equivalent circuit model, the equivalent circuit model of the power battery is obtained based on the operating condition data of the power battery and the battery performance test data, including the following steps: based on the operating condition data of the power battery, the number of charge and discharge cycles of the power battery is obtained; based on the battery performance test data, a first function expression of the resistance value of the ohmic internal resistance and the current charge, the real-time temperature of the power battery, the effective current value of the current source and the number of charge and discharge cycles is fitted; based on the battery performance test data, a second function expression of the resistance value of the polarization resistor and the current charge, the real-time temperature of the power battery, the effective current value of the current source and the number of charge and discharge cycles is fitted; based on the battery performance test data, a third function expression of the capacitance value of the polarization capacitor and the current charge, the real-time temperature of the power battery, the effective current value of the current source and the number of charge and discharge cycles is fitted.

[0010] As a further improvement of the above scheme, the polarization voltage division of the RC circuit is obtained based on the equivalent circuit model and the open circuit voltage, comprising the following steps: using a voltage acquisition circuit to obtain the total voltage of the power battery, and obtaining the effective current value output by the current source; based on the effective current value and the resistance value of the ohmic internal resistor, obtaining the internal resistance voltage division of the ohmic internal resistor; based on the total voltage, the open circuit voltage and the ohmic internal resistance voltage division, obtaining the polarization voltage division of the RC circuit.

[0011] As a further improvement of the above scheme, the method of obtaining the current of the circuit where the power battery is located based on the polarization voltage divider, the polarization resistor and the polarization capacitor includes the following steps: obtaining a first current flowing through the polarization resistor based on the polarization voltage divider and the polarization resistor; obtaining a second current flowing through the polarization capacitor based on the polarization voltage divider and the polarization capacitor; and obtaining the current of the circuit where the power battery is located based on the first current and the second current.

[0012] As a further improvement of the above scheme, the method of obtaining a second current flowing through the polarized capacitor based on the polarization voltage divider and the polarized capacitor includes the following steps: obtaining a pre-polarization voltage at a moment of a previous preset time step; and obtaining a second current flowing through the polarized capacitor based on the polarized capacitor and the difference between the pre-polarization voltage and the polarization voltage at a current moment.

[0013] The present invention also provides a battery current estimation device in a current acquisition circuit failure mode, which applies any of the above-mentioned battery current estimation methods in a current acquisition circuit failure mode, and comprises:

[0014] A charge acquisition module, which is used to acquire the real-time charge of the power battery when a current acquisition circuit failure of the power battery is detected;

[0015] An open circuit voltage acquisition module, which is used to acquire the open circuit voltage of the power battery based on the open circuit voltage test data of the power battery and the real-time charge amount;

[0016] An equivalent model acquisition module, which is used to acquire an equivalent circuit model of the power battery based on the use condition data of the power battery and the battery performance test data; the equivalent circuit model includes an RC circuit composed of an ohmic internal resistance, a polarization resistor and a polarization capacitor, and a current source;

[0017] A polarization voltage division acquisition module, which is used to obtain the polarization voltage division of the RC circuit based on the equivalent circuit model and the open circuit voltage;

[0018] A current calculation module is used to obtain the current of the circuit where the power battery is located based on the polarization voltage division, the polarization resistance and the polarization capacitance.

[0019] Compared with the existing battery current estimation method under the current acquisition circuit failure mode, the battery current estimation method and device under the current acquisition circuit failure mode of the present invention have the following beneficial effects: when the control program detects that the current acquisition circuit of the power battery fails, the real-time charge of the power battery is obtained; based on the open circuit voltage test data of the power battery and the real-time charge, the open circuit voltage of the power battery is obtained; based on the operating condition data of the power battery and the battery performance test data, the equivalent circuit model of the power battery is obtained; the equivalent circuit model includes an RC circuit composed of an ohmic internal resistance, a polarization resistor and a polarization capacitor, and a current source; based on the equivalent circuit model and the open circuit voltage, the polarization partial pressure of the RC circuit is obtained; based on the polarization partial pressure, the polarization resistor and the polarization capacitor, the current of the circuit where the power battery is located is obtained; through the above method, without introducing hardware elements and hardware design costs, when dealing with the sudden failure of the current acquisition circuit of the power battery, the current flowing through the power battery can be obtained quickly and at low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a flowchart of a method for estimating battery current in a current acquisition circuit failure mode according to an embodiment of the present invention.

[0021] Figure 2 The figure is a flow chart of the method for obtaining the open circuit voltage according to an embodiment of the present invention.

[0022] Figure 3 The present invention is a flowchart of the method for obtaining the equivalent model according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] See also Figure 1 In an embodiment of the present application, a method for estimating battery current in a current acquisition circuit failure mode is proposed, and the method comprises the following steps:

[0025] S101, when it is detected that the current collection circuit of the power battery fails, obtaining the real-time charge of the power battery;

[0026] Specifically, when the control program detects that the current acquisition circuit of the power battery is in a faulty state, it is determined that the current acquisition circuit of the power battery has failed, and the moment when the failure of the current acquisition circuit of the power battery is detected is taken as the initial moment. When it is necessary to obtain the current of the power battery at the initial moment and any moment after the initial moment, the current charge of the power battery at any time step from the initial moment is first obtained.

[0027] S102, obtaining an open circuit voltage of the power battery based on the open circuit voltage test data and the real-time charge amount of the power battery;

[0028] Based on the open circuit voltage test data of the power battery and the real-time charge amount, the open circuit voltage of the power battery is obtained, which includes the following steps: taking the open circuit voltage as the dependent variable, the current charge amount as the first independent variable, and the temperature of the power battery as the second independent variable; based on the open circuit voltage test data, obtaining a preset mapping relationship between the dependent variable, the first independent variable and the second independent variable.

[0029] Specifically, after the control program obtains the real-time temperature value of the power battery, the real-time temperature value and the current charge amount are substituted into the preset mapping relationship to obtain the open circuit voltage of the power battery.

[0030] S103, obtaining an equivalent circuit model of the power battery based on the usage condition data of the power battery and the battery performance test data;

[0031] The equivalent circuit model includes an RC circuit composed of an ohmic internal resistance, a polarization resistor and a polarization capacitor, and a current source. Based on the operating condition data of the power battery and the battery performance test data, an equivalent circuit model of the power battery is obtained;

[0032] Among them, the operating condition data includes calendar life data and cycle life data, and the cycle life data includes the number of times the power battery can be charged and discharged in a cycle; the calendar life data refers to the life of the power battery when it is left under a certain power level and temperature conditions.

[0033] Specifically, the control program obtains the number of charge and discharge cycles of the power battery based on the operating condition data of the power battery; based on the battery performance test data, fits a first function expression of the resistance value of the ohmic internal resistance and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source, and the number of charge and discharge cycles; based on the battery performance test data, fits a second function expression of the resistance value of the polarization resistor and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source, and the number of charge and discharge cycles; based on the battery performance test data, fits a third function expression of the capacitance value of the polarization capacitor and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source, and the number of charge and discharge cycles; finally, based on the first function expression of the ohmic internal resistance, the second function expression of the polarization resistor, and the third function expression of the polarization capacitor, the equivalent circuit model of the power battery is obtained.

[0034] S104. Obtain the polarization voltage division of the RC circuit based on the equivalent circuit model and the open circuit voltage.

[0035] Specifically, the control program uses the voltage acquisition circuit to obtain the total voltage of the power battery and the effective current value output by the current source, and then obtains the internal resistance voltage division of the ohmic internal resistance based on the effective current value and the resistance value of the ohmic internal resistance, and finally obtains the polarization voltage division of the RC circuit based on the total voltage, open circuit voltage and the ohmic internal resistance voltage division.

[0036] S105. Obtain a total current of a circuit where the power battery is located based on the polarization voltage division, the polarization resistance, and the polarization capacitance.

[0037] Specifically, based on the polarization voltage division and the polarization resistor, a first current flowing through the polarization resistor is obtained; based on the polarization voltage division and the polarization capacitor, a second current flowing through the polarization capacitor is obtained; based on the first current and the second current, a total current of the circuit where the power battery is located is obtained.

[0038] In the present application, when the control program detects that the current acquisition circuit of the power battery has failed, the real-time charge of the power battery is obtained; based on the open-circuit voltage test data of the power battery and the real-time charge, the open-circuit voltage of the power battery is obtained; based on the operating condition data of the power battery and the battery performance test data, the equivalent circuit model of the power battery is obtained; the equivalent circuit model includes an RC circuit composed of an ohmic internal resistance, a polarization resistor and a polarization capacitor, and a current source; based on the equivalent circuit model and the open-circuit voltage, the polarization partial pressure of the RC circuit is obtained; based on the polarization partial pressure, the polarization resistor and the polarization capacitor, the current of the circuit where the power battery is located is obtained; through the above method, without introducing hardware elements and hardware design costs, when dealing with the sudden failure of the current acquisition circuit of the power battery, the total current flowing through the circuit where the power battery is located can be obtained quickly and at low cost.

[0039] In an application embodiment, please refer to Figure 2 , step S2 comprises:

[0040] S201, obtaining open circuit voltage test data of the power battery;

[0041] S202, taking the open circuit voltage of the power battery as the dependent variable, the current charge as the first independent variable, and the temperature of the power battery as the second independent variable;

[0042] S203: Based on the open circuit voltage test data, obtain a preset mapping relationship between the dependent variable, the first independent variable, and the second independent variable.

[0043] The preset mapping relationship can be expressed as U ocv =f(SOC,T), where U ocv It represents the open circuit voltage of the power battery pack, SOC represents the current charge, and T represents the temperature of the power battery.

[0044] In the embodiment of the present application, the mapping relationship between the charge amount of the power battery and the open circuit voltage of the power battery is obtained by using the open circuit voltage test data, so that the open circuit voltage of the power battery can be more accurately obtained according to the current charge amount of the power battery.

[0045] In an application embodiment, please refer to Figure 3 , step S3 comprises:

[0046] S301, obtaining the number of charge and discharge cycles of the power battery cell based on the usage condition data of the power battery;

[0047] S302, based on the battery performance test data, fitting a first function expression of the resistance value of the ohmic internal resistance and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source, and the number of charge and discharge cycles;

[0048] The first function expression can be R0=f R0 (SOC,T,I,N c ), R0 represents the ohmic internal resistance, I represents the effective current value of the current source, N c It is the number of charge and discharge cycles of the power battery.

[0049] S303, based on the battery performance test data, fitting a second function expression of the resistance value of the polarization resistor and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source, and the number of charge and discharge cycles;

[0050] The second function expression can be R1=f R1 (SOC,T,I,N c ), R1 represents the polarization resistance, I represents the effective current value of the current source, N c It is the number of charge and discharge cycles of the power battery.

[0051] S304, based on the battery performance test data, fitting a third function expression of the capacitance value of the polarized capacitor and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source, and the number of charge and discharge cycles.

[0052] Among them, the third function expression can be C1=f C1 (SOC,T,I,N c ), C1 represents the polarized capacitance, I represents the effective current value of the current source, N c It is the number of charge and discharge cycles of the power battery.

[0053] In the application embodiment, the number of charge and discharge cycles of the power battery is obtained based on the operating condition data of the power battery, and then the function expressions of the polarization resistance and polarization capacitance are fitted based on the battery performance test data, providing a basis for the next step of accurately obtaining the polarization voltage division of the RC circuit.

[0054] It can be understood that in order to further improve the accuracy of the equivalent circuit model, the equivalent circuit model obtained offline can be updated based on the current acquisition value obtained before the current acquisition circuit fails; specifically, the control program obtains the real-time current value according to the current acquisition device, obtains the significant step operating condition according to the real-time current value, and calculates the ratio of the voltage drop and the current difference per unit time step when the power battery is in the significant step operating condition as the updated value of the ohmic internal resistance R0.

[0055] In other embodiments, an operating condition window that can simultaneously reflect the ohmic characteristics and polarization characteristics of the battery can also be selected. The equivalent circuit model performs Laplace transform based on the output and input to obtain the s-domain transfer function, and then obtains the transfer function in the z-domain by z-transform. The ohmic internal resistance R0, polarization resistance R1 and polarization capacitance C1 are identified online based on the recursive least squares method to update the equivalent circuit model.

[0056] In one embodiment of the application, step S4 includes the following steps: using a voltage acquisition circuit to obtain the total voltage of the power battery and obtain the effective current value output by the current source; based on the effective current value and the resistance value of the ohmic internal resistor, obtaining the internal resistance voltage division of the ohmic internal resistor; based on the total voltage, the open circuit voltage and the internal resistance voltage division, obtaining the polarization voltage division of the RC circuit.

[0057] In one embodiment of the application, step S5 includes the following steps:

[0058] S501, obtaining a first current flowing through a polarization resistor based on a polarization voltage division and a polarization resistor;

[0059] S502, obtaining a second current flowing through the polarized capacitor based on the polarized voltage division and the polarized capacitor;

[0060] Specifically, the pre-polarization voltage at the moment of the previous preset time step is obtained; based on the polarization capacitor and the difference between the pre-polarization voltage and the polarization voltage at the current moment, the second current flowing through the polarization capacitor is obtained; wherein the expressions of the second current, the pre-polarization voltage and the polarization voltage at the current moment are as follows:

[0061]

[0062] Where, I2(n) represents the second current, C1(n) represents the polarization capacitance, and U 1st (n) represents the polarization voltage at the current moment, U 1st (n-1) represents the polarization voltage at the previous moment, I(n) represents the total battery current, T s Represents the unit time step.

[0063] S503: Based on the first current and the second current, obtain the current of the circuit where the power battery is located.

[0064] Specifically, the first current is added to the second current to obtain the current of the circuit where the power battery is located.

[0065] It should be noted that the battery pack current error estimated based on the equivalent circuit model is different from the battery pack current error measured based on the acquisition circuit, so the overcurrent threshold of the battery pack current should also be corrected (positive for charging direction and negative for discharging direction).

[0066] λcal =g(λ i ,λ m ,λ u )

[0067]

[0068] Among them, λ u is the battery pack voltage error based on circuit acquisition, λ m Introducing error into the equivalent circuit model, λ i is the current error collected by the current acquisition circuit, I ch and I disch are the overcurrent thresholds for charging and discharging based on the current value collected by the circuit, λ cal is the current value error estimated based on the equivalent circuit model, I ch_cal and I disch_cal They are respectively the overcurrent thresholds for charging and discharging for estimating the current value based on the equivalent circuit model.

[0069] Therefore, considering different factors of battery current error estimation based on the equivalent circuit model and correcting the charge and discharge overcurrent diagnosis threshold, the battery can be better protected.

[0070] In the application embodiment, the second current flowing through the polarization capacitor is calculated based on the difference between the previous polarization voltage and the polarization voltage at the current moment, and then the first current and the second current are added to obtain the total current flowing through the circuit where the power battery is located. Since the second current flowing through the polarization capacitor is taken into account, the total current flowing through the circuit where the power battery is located can be obtained more accurately.

[0071] This embodiment provides a battery current estimation device in a current acquisition circuit failure mode, and a battery current estimation method in a current acquisition circuit failure mode of the device, which includes:

[0072] A charge acquisition module, which is used to acquire the real-time charge of the power battery when a current acquisition circuit failure of the power battery is detected;

[0073] An open circuit voltage acquisition module, which is used to acquire the open circuit voltage of the power battery based on the open circuit voltage test data of the power battery and the real-time charge amount;

[0074] An equivalent model acquisition module, which is used to acquire an equivalent circuit model of the power battery based on the use condition data of the power battery and the battery performance test data; the equivalent circuit model includes an RC circuit composed of an ohmic internal resistance, a polarization resistor and a polarization capacitor, and a current source;

[0075] A polarization voltage division acquisition module, which is used to obtain the polarization voltage division of the RC circuit based on the equivalent circuit model and the open circuit voltage;

[0076] A current calculation module is used to obtain the total current of the circuit where the power battery is located based on the polarization voltage division, the polarization resistance and the polarization capacitance.

[0077] Compared with the prior art, the advantages of the battery current estimation device in the current acquisition circuit failure mode are the same as those of the battery current estimation method in the current acquisition circuit failure mode in Example 1, which will not be elaborated here.

[0078] In one embodiment of the application, a computer terminal is provided, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. The steps of the battery current estimation method in the current acquisition circuit failure mode are implemented when the processor executes the program. When the method is applied, it can be applied in the form of software, such as being designed as an independently running program and installed on a computer terminal, which can be a computer, a smart phone, a control system, and other Internet of Things devices. The method can also be designed as an embedded running program and installed on a computer terminal, such as a single-chip microcomputer.

[0079] In one embodiment of the application, this embodiment provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the battery current estimation method in the current acquisition circuit failure mode are implemented. When the method is applied, it can be applied in the form of software, such as a program designed to be independently run by a computer-readable storage medium, and the computer-readable storage medium can be a U disk, designed as a U shield, and the U disk is designed to start the program of the entire method through an external trigger.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for estimating battery current in a current acquisition circuit failure mode, characterized in that: The method comprises the following steps: When a current acquisition circuit failure of the power battery is detected, the real-time charge of the power battery is obtained; Based on the open circuit voltage test data of the power battery and the real-time charge amount, acquiring the open circuit voltage of the power battery; Based on the operating condition data of the power battery and the battery performance test data, an equivalent circuit model of the power battery is obtained; the equivalent circuit model includes an RC circuit composed of an ohmic internal resistance, a polarization resistor and a polarization capacitor, and a current source; Based on the equivalent circuit model and the open circuit voltage, obtaining the polarization voltage division of the RC circuit; Based on the polarization voltage division, the polarization resistance and the polarization capacitance, a total current of a circuit where the power battery is located is obtained.

2. The battery current estimation method under the current acquisition circuit failure mode according to claim 1, characterized in that: The step of obtaining the open circuit voltage of the power battery based on the open circuit voltage test data of the power battery and the real-time charge amount comprises the following steps: Acquiring open circuit voltage test data of the power battery; Taking the open circuit voltage as a dependent variable, the real-time charge amount as a first independent variable, and the real-time temperature of the power battery as a second independent variable; Based on the open circuit voltage test data, a preset mapping relationship between the dependent variable, the first independent variable and the second independent variable is obtained.

3. The battery current estimation method under the current acquisition circuit failure mode according to claim 2, characterized in that: The step of obtaining the open circuit voltage of the power battery based on the open circuit voltage test data of the power battery and the real-time charge amount comprises the following steps: Obtaining a real-time temperature value of the power battery; Substitute the real-time temperature value and the current charge amount into the preset mapping relationship to obtain the open circuit voltage of the power battery.

4. The battery current estimation method in the current acquisition circuit failure mode according to claim 1, characterized in that: When the equivalent circuit model is a first-order equivalent circuit model, the acquiring of the equivalent circuit model of the power battery based on the usage condition data of the power battery and the battery performance test data comprises the following steps: Based on the operating condition data of the power battery, the number of charge and discharge cycles of the power battery cell is obtained; Based on the battery performance test data, a first function expression is fitted between the resistance value of the ohmic internal resistance and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source, and the number of charge and discharge cycles; Based on the battery performance test data, a second function expression is fitted between the resistance value of the polarization resistor and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source, and the number of charge and discharge cycles; Based on the battery performance test data, a third function expression of the capacitance value of the polarization capacitor and the current charge amount, the real-time temperature of the power battery, the effective current value of the current source and the number of charge and discharge cycles is fitted.

5. The battery current estimation method in the current acquisition circuit failure mode according to claim 4, characterized in that: The step of obtaining the polarization voltage division of the RC circuit based on the equivalent circuit model and the open circuit voltage comprises the following steps: Using a voltage acquisition circuit to obtain the total voltage of the power battery and the effective current value output by the current source; Based on the effective current value and the resistance value of the ohmic internal resistor, obtaining the internal resistance divided voltage of the ohmic internal resistor; Based on the total voltage, the open circuit voltage and the ohmic internal resistance voltage division, the polarization voltage division of the RC circuit is obtained.

6. The battery current estimation method in the current acquisition circuit failure mode according to claim 4, characterized in that: The step of obtaining the current of the circuit where the power battery is located based on the polarization voltage division, the polarization resistance, and the polarization capacitance comprises the following steps: Based on the polarization voltage division and the polarization resistor, obtaining a first current flowing through the polarization resistor; Based on the polarization voltage division and the polarization capacitor, obtaining a second current flowing through the polarization capacitor; Based on the first current and the second current, a current of a circuit where the power battery is located is obtained.

7. The battery current estimation method in the current acquisition circuit failure mode according to claim 6, characterized in that: The step of obtaining a second current flowing through the polarized capacitor based on the polarized voltage division and the polarized capacitor comprises the following steps: Obtaining the pre-polarization voltage at the moment of the previous preset time step; Based on the polarization capacitor and the difference between the pre-polarization voltage and the polarization voltage at a current moment, a second current flowing through the polarization capacitor is obtained.

8. A battery current estimation device in a current acquisition circuit failure mode, the device comprising: A charge acquisition module, which is used to acquire the real-time charge of the power battery when a current acquisition circuit failure of the power battery is detected; An open circuit voltage acquisition module, which is used to acquire the open circuit voltage of the power battery based on the open circuit voltage test data of the power battery and the real-time charge amount; An equivalent model acquisition module, which is used to acquire an equivalent circuit model of the power battery based on the use condition data of the power battery and the battery performance test data; the equivalent circuit model includes an RC circuit composed of an ohmic internal resistance, a polarization resistor and a polarization capacitor, and a current source; A polarization voltage division acquisition module, which is used to obtain the polarization voltage division of the RC circuit based on the equivalent circuit model and the open circuit voltage; A current calculation module is used to obtain the current of the circuit where the power battery is located based on the polarization voltage division, the polarization resistance and the polarization capacitance.

9. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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