Method and device for detecting short-circuit resistance in battery on line

Abstract

The invention relates to a method and a device for detecting short-circuit resistance in a battery on line, and the method comprises the steps: applying two constant-current pulses with different amplitudes to the battery when the battery is in a working state; acquiring at least two groups of dynamic response data; calculating the equivalent ohmic internal resistance of the battery according to the dynamic response data; respectively obtaining voltage difference models corresponding to the two constant current pulses according to the current working state of the battery; and calculating the internal short-circuit resistance of the battery in the current working state based on a voltage difference model and the equivalent ohmic internal resistance. The method has the advantages that the two constant-current pulses with different amplitudes are applied to the battery, then the dynamic response data of the battery are collected to obtain the voltage difference model corresponding to the constant-current pulses, the internal short-circuit resistance of the battery in the current working state is calculated through the voltage difference model and the equivalent ohmic internal resistance, internal short-circuit resistance detection is achieved, and the accuracy is high.

Description

Technical Field

[0001] This invention relates to the field of battery internal short-circuit resistance detection technology, and in particular to a method and apparatus for online detection of battery internal short-circuit resistance. Background Technology

[0002] Current methods for detecting internal short circuits in batteries primarily rely on monitoring battery voltage and temperature. For example, detecting an abnormal drop in battery terminal voltage can indicate whether an internal short circuit has occurred. However, this method has low sensitivity, typically only triggering an alarm when the internal short circuit has progressed to a significant level, causing a substantial voltage drop. Methods that rely on monitoring abnormal increases in battery surface or ambient temperature also exhibit lag and are susceptible to interference from external factors such as charge / discharge rate and heat dissipation conditions, resulting in a high false alarm rate. Summary of the Invention

[0003] The technical problem to be solved by the embodiments of the present invention is to provide a method and apparatus for online detection of the internal short-circuit resistance of a battery. By applying two constant current pulses of different amplitudes to the battery and collecting the dynamic response data of the battery, a voltage difference model corresponding to the constant current pulse is obtained. The internal short-circuit resistance of the battery under the current working state is calculated using the voltage difference model and the equivalent ohmic internal resistance, thereby realizing the detection of internal short-circuit resistance with high accuracy.

[0004] To address the aforementioned technical problems, this invention provides a method for online detection of the short-circuit resistance within a battery, comprising: When the battery is in operation, two constant current pulses of different amplitudes are applied to the battery; Collect at least two sets of dynamic response data; The equivalent ohmic internal resistance of the battery is calculated based on the dynamic response data. Based on the current operating state of the battery, obtain the voltage difference model corresponding to the two constant current pulses respectively; The internal short-circuit resistance of the battery under the current operating state is calculated based on the voltage difference model and the equivalent ohmic internal resistance.

[0005] In one feasible implementation, during the step of applying two constant current pulses of different amplitudes to the battery while it is in an active state, The battery is in either a discharge state or a charging state; the constant current pulse is either a pulse in the charging direction or a pulse in the discharging direction.

[0006] In one feasible implementation, the constant current pulse applied to the battery is in a stable phase before at least two sets of dynamic response data are acquired; the dynamic response data includes the battery's terminal voltage and current.

[0007] In one feasible implementation, the equivalent ohmic resistance is calculated using the following formula. ; in, This represents the equivalent ohmic internal resistance; This represents the terminal voltage in the dynamic response data of the first group; This represents the terminal voltage in the dynamic response data of the second group; This represents the current in the dynamic response data of the first group; This represents the current in the dynamic response data of the second group.

[0008] In one feasible implementation, obtaining the voltage difference model corresponding to the two constant current pulses based on the current operating state of the battery includes: When the battery is in the charging state, the voltage difference model is calculated based on the equivalent circuit model and the compensation voltage. The voltage difference model is as follows: ; in, This indicates the voltage difference of the battery when it is in the charging state. This represents the current in the dynamic response data of the first group; This represents the equivalent ohmic internal resistance; This indicates the internal short-circuit resistance.

[0009] In one feasible implementation, obtaining the voltage difference model corresponding to the two constant current pulses based on the current operating state of the battery includes: When the battery is in the discharge state, the voltage difference model is calculated based on the equivalent circuit model and the compensation voltage. The voltage difference model is as follows: ; in, This represents the voltage difference of the battery when it is in the aforementioned discharge state; This represents the current in the dynamic response data of the first group; This represents the equivalent ohmic internal resistance; This indicates the internal short-circuit resistance.

[0010] In one feasible implementation, calculating the battery's internal short-circuit resistance in the current operating state based on the voltage difference model and the equivalent ohmic internal resistance includes, when the battery is in the charging state, the internal short-circuit resistance being calculated using the following formula. ; in, This indicates the internal short-circuit resistance; This represents the equivalent ohmic internal resistance; This indicates the voltage difference of the battery when it is in the charging state. This represents the current in the dynamic response data of the first group.

[0011] In one feasible implementation, calculating the battery's internal short-circuit resistance under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance includes, when the battery is in the discharge state, the internal short-circuit resistance being calculated using the following formula. ; in, This indicates the internal short-circuit resistance; This represents the equivalent ohmic internal resistance; This represents the voltage difference of the battery when it is in the aforementioned discharge state; This represents the current in the dynamic response data of the first group.

[0012] In one feasible implementation, after calculating the battery's internal short-circuit resistance under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance, the method for online detection of the battery's internal short-circuit resistance further includes... The internal short-circuit resistance is compared with a preset threshold. If the internal short-circuit resistance is less than the preset threshold, it is determined that the battery has an internal short circuit.

[0013] Accordingly, this application also relates to an apparatus for online detection of the internal short-circuit resistance of a battery, used to implement the aforementioned method for online detection of the internal short-circuit resistance of a battery, including, The pulse excitation unit is configured to apply two constant current pulses of different amplitudes to the battery when the battery is in the working state. The data acquisition unit is configured to acquire at least two sets of dynamic response data. The first calculation unit is configured to calculate the equivalent ohmic internal resistance of the battery based on the dynamic response data. The model building unit is configured to obtain the voltage difference model corresponding to the two constant current pulses according to the current working state of the battery. The second calculation unit is configured to calculate the internal short-circuit resistance of the battery under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance.

[0014] Implementing this invention has the following beneficial effects: By applying two constant current pulses of different amplitudes to the battery and collecting the battery's dynamic response data, a voltage difference model corresponding to the constant current pulse is obtained. The internal short-circuit resistance of the battery under the current operating state is calculated using the voltage difference model and the equivalent ohmic internal resistance, thus realizing the detection of internal short-circuit resistance with high accuracy.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0016] Figure 1 This is a step diagram of the method for using an internal short-circuit resistor in one embodiment of the present invention; Figure 2 This is a step diagram of the method for using an internal short-circuit resistor in another embodiment of the present invention; Figure 3 This is a circuit diagram of the battery in a charging state in one embodiment of the present invention; Figure 4 This is a circuit diagram of the battery in a discharging state in one embodiment of the present invention; Figure 5 This is a schematic diagram of a constant current discharge pulse in one embodiment of the present invention; Figure 6 This is a schematic diagram of the dynamic response of battery voltage in one embodiment of the present invention; Figure 7 This is a schematic diagram of an internal short-circuit resistor device in one embodiment of the present invention. Detailed Implementation

[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0018] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0020] Current methods for detecting internal short circuits in batteries primarily rely on monitoring battery voltage and temperature, such as detecting abnormal drops in battery terminal voltage to determine an internal short circuit. However, this method has low sensitivity, typically only triggering an alarm when the internal short circuit has progressed to a significant level, causing a substantial voltage drop, thus failing to provide early warning. Secondly, methods that rely on monitoring abnormal increases in battery surface or ambient temperature also suffer from latency and are easily affected by external factors such as charge / discharge rate and heat dissipation conditions, resulting in a high false alarm rate. Most current technologies can only provide a qualitative "present" or "absent" assessment, unable to quantitatively evaluate the severity of an internal short circuit, thus hindering the battery management system from providing accurate warnings and appropriate countermeasures.

[0021] A method for online detection of short-circuit resistance within a battery cell, referring to... Figure 1 ,include, Step S100: When the battery is in working condition, two constant current pulses of different amplitudes are applied to the battery. Step S200: Collect at least two sets of dynamic response data; Step S300: Calculate the equivalent ohmic internal resistance of the battery based on the dynamic response data; Step S400: Obtain the voltage difference model corresponding to the two constant current pulses according to the current working state of the battery. Step S500: Calculate the internal short-circuit resistance of the battery under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance.

[0022] For example, in step S100, when the battery is in the working state, the step of applying two constant current pulses of different amplitudes to the battery... The battery is in either a discharge state or a charging state; the constant current pulse is either a pulse in the charging direction or a pulse in the discharging direction.

[0023] Specifically, when the battery is in a charging state, two constant current pulses of different amplitudes are applied to the battery in sequence, wherein the constant current pulses can be either pulses in the charging direction or pulses in the discharging direction; when the battery is in a discharging state, two constant current pulses of different amplitudes are applied to the battery in sequence, wherein the constant current pulses can be either pulses in the charging direction or pulses in the discharging direction.

[0024] For example, before acquiring at least two sets of dynamic response data in step S200, the constant current pulse applied to the battery is in a stable phase; the dynamic response data includes the battery's terminal voltage and current.

[0025] Specifically, when the battery is charging, after applying two constant current pulses of different amplitudes to the battery, the battery's terminal voltage and current are collected at high frequency during the pulse stabilization phase; when the battery is discharging, after applying two constant current pulses of different amplitudes to the battery, the battery's terminal voltage and current are collected at high frequency during the pulse stabilization phase.

[0026] Reference Figure 5 , Figure 5 This is a schematic diagram of a constant current discharge pulse. The horizontal axis represents time (in seconds), and the vertical axis represents current (in A). During the first 0-10 seconds, the current is 0 (the battery is not discharging). Around 10 seconds, a small-amplitude constant current discharge pulse (approximately 1 A) is applied, lasting briefly before returning to 0. Around 20 seconds, a second large-amplitude constant current discharge pulse (approximately 5 A) is applied, also lasting briefly before returning to 0. This is a complete cycle of applying two constant current pulses of different amplitudes to the battery.

[0027] Reference Figure 6 , Figure 6 This is a schematic diagram of the battery voltage dynamic response, with the horizontal axis representing time (in seconds) and the vertical axis representing voltage (in V). Its changes are synchronized with the aforementioned current pulses: from 0-10 seconds, the voltage stabilizes at approximately 4V; at 10 seconds, with the first small current pulse, the voltage briefly drops to 3.9V before quickly recovering; at 20 seconds, with the second large current pulse, the voltage experiences a more significant brief drop (down to approximately 3.5V), subsequently also quickly recovering to a stable value, demonstrating the dynamic response characteristics of the battery voltage to discharge pulses of different amplitudes.

[0028] Step S200 can collect at least two sets of dynamic response data. The first set of dynamic response data can be ( , The dynamic response data of the second group can be ( ); , ).

[0029] Reference Figure 3 , Figure 3This is a circuit diagram of a battery in a charging state. When the battery is charging, an external current I flows into the circuit from the right end. There are two parallel current paths in the circuit: Path 1 (normal charging path): Current I first flows through the ohmic internal resistance r, and then flows into the voltage source (completing the electrochemical process of charging); Path 2 (internal short-circuit branch): because... Connected in parallel with the battery body, part of the current will flow from r and The connection point is split, via Formation of internal short-circuit current (in the picture) The arrow points downwards, flowing from the parallel point. ).

[0030] For example, in order to correct the open-circuit voltage caused by an internal short circuit The mismatch between the OCV-SOC meter and the normal battery OCV-SOC meter necessitates the introduction of a compensation voltage. , Figure 3 In the charging state, Figure 3 The battery terminal voltage is The compensation voltage is The charging current is The internal short-circuit current is The internal resistance of the ohms is r, and the internal short-circuit resistance is... The voltage difference is The measured open-circuit voltage is An equivalent circuit model exists: ; ; .

[0031] Reference Figure 4 , Figure 4 This is a circuit diagram of a battery in a discharging state. When the battery is discharging, current I flows out from the right end of the circuit, and there are two parallel current paths in the circuit: Pathway 1 (Normal Discharge Path): The battery's electrochemical energy is transmitted through the voltage source. At output, after the current flows through the ohmic internal resistance r, a portion of the current I flows out of the battery; Path 2 (Internal Short Circuit Branch): Because Connected in parallel with the main battery, another portion of the current will flow from r and The connection point shunts the current, forming an internal short-circuit current. .

[0032] For example, in order to correct the open-circuit voltage caused by an internal short circuit The mismatch between the OCV-SOC meter and the normal battery OCV-SOC meter necessitates the introduction of a compensation voltage. , Figure 4In the mid-discharge state, Figure 4 The battery terminal voltage is The compensation voltage is The discharge current is The internal short-circuit current is The internal resistance of the ohms is r, and the internal short-circuit resistance is... The voltage difference is The measured open-circuit voltage is An equivalent circuit model exists: ; ; .

[0033] As mentioned above: An internally short-circuited battery, due to the continuous shunt current within it, causes the open-circuit voltage measured when it is at rest to be... This model cannot match the true open-circuit voltage (OCV) in the normal battery SOC-OCV curve. To correct this systematic error, this invention explicitly defines the ideal voltage source in the model as a compensation voltage. (Replaces the original one that did not consider deviations) , (This is the static open-circuit voltage obtained through testing). and The relationship is: ; In a feasible implementation, the equivalent ohmic internal resistance is calculated using the following formula. ; in, This represents the equivalent ohmic internal resistance; This represents the terminal voltage in the dynamic response data of the first group; This represents the terminal voltage in the dynamic response data of the second group; This represents the current in the dynamic response data of the first group; This represents the current in the dynamic response data of the second group.

[0034] For example, based on the current operating state of the battery, the voltage difference model corresponding to the two constant current pulses is obtained, including: When the battery is in a charging state, based on the equivalent circuit model of the charging process and the compensation voltage The voltage difference model is derived and calculated as follows: ; in, This indicates the voltage difference when the battery is charging; This represents the current in the dynamic response data of the first group; This represents the equivalent ohmic internal resistance; This indicates the internal short-circuit resistance.

[0035] For example, based on the current operating state of the battery, the voltage difference model corresponding to the two constant current pulses is obtained, including: When the battery is in a discharging state, the equivalent circuit model based on the discharging process and the compensation voltage are used. The voltage difference model is derived and calculated as follows: ; in, This represents the voltage difference when the battery is in a discharging state; This represents the current in the dynamic response data of the first group; This represents the equivalent ohmic internal resistance; This indicates the internal short-circuit resistance.

[0036] For example, step S500 calculates the internal short-circuit resistance of the battery in the current operating state based on the voltage difference model and the equivalent ohmic internal resistance, including the internal short-circuit resistance when the battery is in a charging state. It is calculated using the following formula. ; in, Indicates the internal short-circuit resistance; This represents the equivalent ohmic internal resistance; This indicates the voltage difference when the battery is charging; This represents the current in the dynamic response data of the first group.

[0037] For example, step S500 calculates the internal short-circuit resistance of the battery in the current operating state based on the voltage difference model and the equivalent ohmic internal resistance, including the internal short-circuit resistance when the battery is in a discharging state. It is calculated using the following formula. ; in, Indicates the internal short-circuit resistance; This represents the equivalent ohmic internal resistance; This represents the voltage difference when the battery is in a discharging state; This represents the current in the dynamic response data of the first group.

[0038] In one feasible implementation, after calculating the battery's internal short-circuit resistance in the current operating state based on the voltage difference model and the equivalent ohmic internal resistance in step S500, referring to... Figure 2 , Figure 2 This is a flowchart illustrating the steps of a method for detecting internal short-circuit resistance in another embodiment of the present invention. The method for online detection of internal short-circuit resistance in a battery further includes... Step S600: Compare the internal short-circuit resistance with a preset threshold. If the internal short-circuit resistance is less than the preset threshold, it is determined that the battery has an internal short circuit. The preset threshold is adjusted according to the battery system. For example, for a ternary lithium battery system, the preset threshold can be set to 1000 ohms. If the internal short-circuit resistance is less than 1000 ohms, it is determined that the battery has an internal short circuit. Specifically, an internal short-circuit resistance less than 1 ohm is considered a severe internal short circuit, between 1 ohm and 100 ohms is considered a moderate internal short circuit, and between 100 ohms and 1000 ohms is considered a mild internal short circuit.

[0039] Accordingly, this application also relates to a device for online detection of short-circuit resistance within a battery, referring to... Figure 7 The method for implementing the above-described online detection of short-circuit resistance within a battery includes, The pulse excitation unit 10 is configured to apply two constant current pulses of different amplitudes to the battery when the battery is in the working state. Data acquisition unit 20 is configured to acquire at least two sets of dynamic response data; The first calculation unit 30 is configured to calculate the equivalent ohmic internal resistance of the battery based on the dynamic response data. Model building unit 40 is configured to obtain the voltage difference model corresponding to the two constant current pulses according to the current working state of the battery. The second calculation unit 50 is configured to calculate the internal short-circuit resistance of the battery under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance.

[0040] For example, the pulse excitation unit 10 provides detection excitation to the battery in the working state. Based on pulse detection technology, it applies two constant current pulses with different amplitudes to the battery (using the difference in current amplitude to amplify the difference in battery electrical characteristics) to provide differentiated excitation signals for subsequent data acquisition, ensuring that the internal short-circuit characteristics of the battery can be accurately captured.

[0041] The data acquisition unit 20 is used to acquire the electrical response of the battery to pulse excitation, and simultaneously acquire the terminal voltage and current data of each pulse stabilization phase to form at least two sets of dynamic response datasets, providing raw data support for subsequent parameter calculations and ensuring the correspondence between the data and the pulse excitation.

[0042] The function of the first calculation unit 30 is to obtain the basic electrical parameters of the battery, and to derive the formula using the voltage-current data corresponding to the double pulse and Ohm's law. Calculating the equivalent ohmic internal resistance helps eliminate internal short-circuit interference, obtains the accurate value of the battery's inherent internal resistance, and lays the groundwork for solving the internal short-circuit resistance.

[0043] The function of model building unit 40 is to establish a correlation model between pulse response and internal short circuit. Based on the current operating state of the battery (charging / discharging), it constructs voltage difference models corresponding to the constant current pulse (during charging). During discharge This transforms measurable voltage data into characteristic parameters that reflect the internal short-circuit state.

[0044] The function of the second calculation unit 50 is to obtain the quantified internal short-circuit resistance, substitute it into the voltage difference model and the equivalent ohmic internal resistance, and derive the core formula for the internal short-circuit resistance ( The solution is obtained, and the accurate internal short-circuit resistance value is output, realizing the quantitative detection of internal short-circuit faults.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for online detection of short-circuit resistance within a battery, characterized in that, include, When the battery is in operation, two constant current pulses of different amplitudes are applied to the battery; Collect at least two sets of dynamic response data; The equivalent ohmic internal resistance of the battery is calculated based on the dynamic response data. Based on the current operating state of the battery, obtain the voltage difference model corresponding to the two constant current pulses respectively; The internal short-circuit resistance of the battery under the current operating state is calculated based on the voltage difference model and the equivalent ohmic internal resistance.

2. The method for online detection of short-circuit resistance in a battery according to claim 1, characterized in that, In the step of applying two constant current pulses of different amplitudes to the battery while it is in operation, The battery is in either a discharge state or a charging state; the constant current pulse is either a pulse in the charging direction or a pulse in the discharging direction.

3. The method for online detection of short-circuit resistance in a battery according to claim 2, characterized in that, The constant current pulse applied to the battery is in a stable phase before at least two sets of dynamic response data are acquired; the dynamic response data includes the battery's terminal voltage and current.

4. The method for online detection of short-circuit resistance in a battery according to claim 3, characterized in that, The equivalent ohmic internal resistance is calculated using the following formula. ； in, This represents the equivalent ohmic internal resistance; This represents the terminal voltage in the dynamic response data of the first group; This represents the terminal voltage in the dynamic response data of the second group; This represents the current in the dynamic response data of the first group; This represents the current in the dynamic response data of the second group.

5. The method for online detection of short-circuit resistance in a battery according to claim 3, characterized in that, The step of obtaining the voltage difference model corresponding to the two constant current pulses based on the current operating state of the battery includes, When the battery is in the charging state, the voltage difference model is calculated based on the equivalent circuit model and the compensation voltage. The voltage difference model is as follows: ； in, This indicates the voltage difference of the battery when it is in the charging state. This represents the current in the dynamic response data of the first group; This represents the equivalent ohmic internal resistance; This indicates the internal short-circuit resistance.

6. The method for online detection of short-circuit resistance in a battery according to claim 3, characterized in that, The step of obtaining the voltage difference model corresponding to the two constant current pulses based on the current operating state of the battery includes, When the battery is in the discharge state, the voltage difference model is calculated based on the equivalent circuit model and the compensation voltage. The voltage difference model is as follows: ； in, This represents the voltage difference of the battery when it is in the aforementioned discharge state; This represents the current in the dynamic response data of the first group; This represents the equivalent ohmic internal resistance; This indicates the internal short-circuit resistance.

7. The method for online detection of short-circuit resistance in a battery according to claim 5, characterized in that, The calculation of the battery's internal short-circuit resistance under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance includes, when the battery is in the charging state, the internal short-circuit resistance being calculated using the following formula. ； in, This indicates the internal short-circuit resistance; This represents the equivalent ohmic internal resistance; This indicates the voltage difference of the battery when it is in the charging state. This represents the current in the dynamic response data of the first group.

8. The method for online detection of short-circuit resistance in a battery according to claim 6, characterized in that, The calculation of the battery's internal short-circuit resistance under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance includes, when the battery is in the discharge state, the internal short-circuit resistance being calculated using the following formula. ； in, This indicates the internal short-circuit resistance; This represents the equivalent ohmic internal resistance; This represents the voltage difference of the battery when it is in the aforementioned discharge state; This represents the current in the dynamic response data of the first group.

9. The method for online detection of short-circuit resistance in a battery according to claim 1, characterized in that, After calculating the battery's internal short-circuit resistance under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance, the method for online detection of the battery's internal short-circuit resistance further includes... The internal short-circuit resistance is compared with a preset threshold. If the internal short-circuit resistance is less than the preset threshold, it is determined that the battery has an internal short circuit.

10. A device for online detection of short-circuit resistance within a battery, characterized in that, A method for implementing the online detection of short-circuit resistance within a battery as described in any one of claims 1-9, comprising: The pulse excitation unit is configured to apply two constant current pulses of different amplitudes to the battery when the battery is in the working state. The data acquisition unit is configured to acquire at least two sets of dynamic response data. The first calculation unit is configured to calculate the equivalent ohmic internal resistance of the battery based on the dynamic response data. The model building unit is configured to obtain the voltage difference model corresponding to the two constant current pulses according to the current working state of the battery. The second calculation unit is configured to calculate the internal short-circuit resistance of the battery under the current operating state based on the voltage difference model and the equivalent ohmic internal resistance.

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