A battery equivalent internal resistance estimation method and device, and readable storage medium

Abstract

The present invention provides a method and device for estimating the equivalent internal resistance of a battery, as well as a readable storage medium. The method comprises the following steps: obtaining operating data of a battery module; selecting operating data for an equivalent charge and discharge period from the operating data, wherein the equivalent charge and discharge period consists of a pair of charging and discharging periods with the same SOC variation; calculating the charging temperature change rate and average charging current based on the operating data for the charging period within the equivalent charge and discharge period, and calculating the discharge temperature change rate and average discharge current based on the operating data for the discharging period; and calculating the equivalent internal resistance of the battery module based on the charging temperature change rate, charging current, discharge temperature change rate, and discharge current. The battery internal resistance estimation method provided by the present invention can be used to estimate the battery internal resistance based on operating data collected from a power station. It is low-cost, suitable for various operating conditions, and has a wide range of applications.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method and device for estimating battery equivalent internal resistance, and a readable storage medium. Background Art

[0002] Battery equivalent internal resistance is a key indicator of battery performance. Its magnitude and changes reflect the battery's discharge capacity, charging efficiency, and energy loss. Regularly calculating and monitoring a power plant's battery equivalent internal resistance allows plant operators to better manage and optimize the battery system, improving plant efficiency and reliability. However, standardized testing methods are not applicable to real power plants, and most algorithms are only suitable for relatively stable operating conditions, such as constant current peak regulation. Therefore, a battery equivalent internal resistance estimation method with a wider range of application scenarios is needed to enable safety monitoring of power plants under a wider range of operating conditions. Summary of the Invention

[0003] The purpose of the present invention is to provide a battery equivalent internal resistance estimation method and device, and a readable storage medium, so as to solve the problems existing in the prior art.

[0004] The technical solutions provided by the present invention are as follows:

[0005] A method for estimating equivalent internal resistance of a battery includes: obtaining operating data of a battery module, the operating data including the state of charge (SOC), charging current, and temperature of the battery module at various sampling moments during a charging process, and the state of charge (SOC), discharge current, and temperature of the battery module at various sampling moments during a discharging process;

[0006] Filtering out the operating data of the equivalent charge and discharge period from the operating data of the battery module, where the equivalent charge and discharge period consists of a pair of charging period and discharging period with the same SOC change;

[0007] Calculating the charging temperature change rate and the average charging current based on the operating data of the charging period in the equivalent charging and discharging period, and calculating the discharging temperature change rate and the average discharging current based on the operating data of the discharging period in the equivalent charging and discharging period;

[0008] According to the charging temperature change rate T' 充电 , average charging current I 充电 , discharge temperature change rate T' 放电 and the average discharge current I 放电 , calculate the equivalent internal resistance r of the battery module during the equivalent charge and discharge period according to the following formula:

[0009]

[0010] Where ρ is the density of the battery module, C pis the equivalent specific heat capacity of the battery module, k is the thermal conductivity of the battery module, and V is the volume of the battery module.

[0011] In some embodiments, the method further includes calculating the internal resistance of each single cell in the battery module based on the equivalent internal resistance r of the battery module.

[0012] In some embodiments, the correlation coefficient c between the voltage and temperature change of the i-th single cell of the battery module is obtained. i ; Calculate the internal resistance r of the i-th single cell in the battery module according to the following formula i :

[0013] r i =c i ×r; where r is the equivalent internal resistance of the battery module.

[0014] In some embodiments, calculating the charging temperature change rate based on operating data of a charging period in an equivalent charging and discharging period includes:

[0015] Obtaining a temperature change in the charging period during the equivalent charging and discharging period according to the temperature at the start sampling moment and the temperature at the end sampling moment of the charging period during the equivalent charging and discharging period;

[0016] The charging temperature change rate is obtained by dividing the temperature change in the charging period in the equivalent charging and discharging period by the duration of the charging period in the equivalent charging and discharging period;

[0017] The discharge temperature change rate is calculated based on the operating data of the discharge period in the equivalent charge and discharge period, including:

[0018] Obtaining a temperature change during the discharge period in the equivalent charge and discharge period according to the temperature at the start sampling moment and the temperature at the end sampling moment of the discharge period in the equivalent charge and discharge period;

[0019] The discharge temperature change rate is obtained by dividing the temperature change amount during the discharge period in the equivalent charge and discharge period by the duration of the discharge period in the equivalent charge and discharge period.

[0020] In some embodiments, if the operating data of the battery module includes multiple equivalent charge and discharge time periods, the equivalent internal resistance of the battery module in the corresponding time period is calculated based on the operating data of each equivalent charge and discharge time period;

[0021] The average equivalent internal resistance of the battery module is calculated based on the equivalent internal resistance of the battery module during multiple equivalent charge and discharge periods.

[0022] In some embodiments, the operating data of the battery module is obtained from the operating data collected from the power station.

[0023] The present invention also provides a battery equivalent internal resistance estimation device, comprising: a data acquisition module for acquiring operating data of a battery module, the operating data including the state of charge (SOC), charging current, and temperature of the battery module at various sampling moments during a charging process, and the state of charge (SOC), discharge current, and temperature at various sampling moments during a discharging process;

[0024] A data screening module is used to screen out the operating data of an equivalent charge and discharge period from the operating data of the battery module, where the equivalent charge and discharge period consists of a pair of charging period and discharging period with the same SOC change;

[0025] The internal resistance calculation module is used to calculate the charging temperature change rate and the average charging current according to the operating data of the charging period in the equivalent charging and discharging period, and calculate the discharge temperature change rate and the average discharge current according to the operating data of the discharge period in the equivalent charging and discharging period; according to the charging temperature change rate T' 充电 , average charging current I 充电 , discharge temperature change rate T' 放电 and the average discharge current I 放电 , calculate the equivalent internal resistance r of the battery module during the equivalent charge and discharge period according to the following formula:

[0026]

[0027] Where ρ is the density of the battery module, C p is the equivalent specific heat capacity of the battery module, k is the thermal conductivity of the battery module, and V is the volume of the battery module.

[0028] In some embodiments, the internal resistance calculation module is further used to calculate the internal resistance of each single cell in the battery module based on the equivalent internal resistance r of the battery module.

[0029] Compared with the existing technology, the battery equivalent internal resistance estimation method and device, and readable storage medium provided by the present invention can bring the following beneficial effects: the present invention estimates the equivalent internal resistance based on the heat loss of the battery module, and can estimate the equivalent internal resistance of the battery module according to the operating data collected by the power station. It has low cost, is suitable for various working conditions, can perform safety monitoring of power stations under any working conditions, and has a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The preferred embodiment will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of a battery equivalent internal resistance estimation method and device, and a readable storage medium.

[0031] Figure 1 is a flow chart of an embodiment of a method for estimating equivalent internal resistance of a battery according to the present invention;

[0032] Figure 2 It is a structural schematic diagram of an embodiment of a battery equivalent internal resistance estimation device of the present invention;

[0033] Figure 3 It is a schematic diagram of the collected SOC variation curve over time;

[0034] Figure 4 It is a structural schematic diagram of another embodiment of a battery equivalent internal resistance estimation device of the present invention. DETAILED DESCRIPTION

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings and other embodiments can be obtained based on these drawings without inventive work.

[0036] To simplify the drawings, only the parts relevant to the present invention are schematically shown in each figure. They do not represent the actual structure of the product. Furthermore, to simplify the drawings and facilitate understanding, in some figures, only one of the components with the same structure or function is schematically depicted or labeled. As used herein, "one" not only means "only one" but also "more than one."

[0037] In one embodiment of the present invention, Figure 1 As shown, a method for estimating the equivalent internal resistance of a battery includes:

[0038] Step S100 acquires operating data of a battery module, where the operating data includes the state of charge (SOC), charging current, and temperature of the battery module at each sampling moment during the charging process, and the state of charge (SOC), discharging current, and temperature at each sampling moment during the discharging process.

[0039] Specifically, we can first obtain the operating data of the power station in the recent period, and use the battery module (or battery cluster, which is a combination of multiple battery units to provide greater power and power output) as the unit, and filter out the operating data of the battery modules that have both charging and discharging processes in the recent period. Subsequently, we can estimate the equivalent internal resistance based on the operating data of these battery modules.

[0040] Operational data includes battery module data at multiple sampling points. Each sampling point includes the battery module's state of charge (SOC), charge / discharge current, and temperature. SOC can be calculated using the ampere-hour integration method and the open-circuit voltage method, while voltage and temperature are measured using sensors.

[0041] The state of charge (SOC) is numerically defined as the ratio of the current capacity to the nominal capacity of the battery. It is usually expressed as a percentage and ranges from 0 to 100%. When SOC = 0, it means the battery is fully discharged, and when SOC = 100%, it means the battery is fully charged.

[0042] Step S200 selects the operation data of the equivalent charge and discharge period from the operation data of the battery module. The equivalent charge and discharge period consists of a pair of charge period and discharge period with the same SOC change.

[0043] Specifically, if a charging period is from a first SOC to a second SOC, and a discharging period is from the second SOC to the first SOC, then the SOC change in the charging period and the discharging period are considered to be the same. A pair of charging and discharging periods with the same SOC change constitutes an equivalent charging and discharging period. For example, if the period during which a battery module charges from SOC1 to SOC2 is recorded as a charging period, then the discharging period from SOC2 to SOC1 is considered to be a discharging period with the same SOC change as the charging period. The reverse is also true.

[0044] The charging period and the discharging period in the equivalent charging and discharging period each include data at least at two sampling moments, and may also include data at multiple sampling moments. Figure 3 As shown, the period when the SOC of the battery module increases from 53% to about 90% (a charging period) and the period when the SOC of the battery module decreases from about 90% to about 53% (a discharging period) constitute an equivalent charging and discharging period.

[0045] From the heat release analysis of the battery cell during the charging and discharging process, it can be seen that the total heat generated by the battery cell during the charging process is Q 充电 For: Q 充电 =Q1 极化 +Q1 欧姆 +Q1 副反应 , the total heat generated during the discharge process Q 放电 For: Q 放电 =Q2 极化 +Q2 欧姆 +Q2 副反应 .

[0046] The equivalent internal resistance of the battery module includes DC internal resistance and polarization internal resistance. 极化 The heat generated by the polarization internal resistance during the charging process, Q1 欧姆 The heat generated by the DC internal resistance during the charging process, Q1 副反应 It is the side reaction heat generated during the charging process. Q2 极化 The heat generated by the polarization internal resistance during the discharge process, Q2 欧姆 The heat generated by the DC internal resistance during the discharge process, Q2 副反应This is side reaction heat generated during the discharge process. This heat is generated by unexpected, abnormal chemical reactions within the battery, such as electrolyte decomposition or reactions between the electrolyte and electrodes. This side reaction heat is reversible, meaning it is absorbed during charging and released during discharge.

[0047] Because the SOC changes during the charging and discharging periods of an equivalent charge-discharge period are the same, the side reaction heat generated during the charging period is equivalent to the side reaction heat generated during the discharging period, but in opposite forms (i.e., one releases heat and the other absorbs heat). Therefore, the side reaction heat generated during these two periods can cancel each other out. Therefore, this pair of charge-discharge periods is called an equivalent charge-discharge period. In this way, the heat generated during the equivalent charge-discharge period is only the heat generated by the equivalent internal resistance.

[0048] Step S300 calculates the charge temperature change rate and the average charge current based on the operation data of the charge period in the equivalent charge and discharge period, and calculates the discharge temperature change rate and the average discharge current based on the operation data of the discharge period in the equivalent charge and discharge period;

[0049] Step S400 is based on the charging temperature change rate T' 充电 , average charging current I 充电 , discharge temperature change rate T' 放电 and the average discharge current I 放电 , calculate the equivalent internal resistance r of the battery module during the equivalent charge and discharge period according to the following formula:

[0050]

[0051] Where ρ is the density of the battery module, C p is the equivalent specific heat capacity of the battery module, k is the thermal conductivity of the battery module, and V is the volume of the battery module.

[0052] Specifically, in addition to heat generation, heat transfer also occurs in the battery module during the charging and discharging process.

[0053] The heat transfer of batteries includes: heat conduction of the internal materials of the battery, heat radiation from the battery surface to the outside world, heat convection of the electrolyte inside the battery, and convection heat dissipation between the battery surface and the coolant. Taking a battery module as the unit of consideration, the most common heat transfer method is convection heat dissipation, and heat conduction and heat radiation can be ignored. In convection heat dissipation, because the flow of electrolyte in the battery is very small, the convection movement of the electrolyte can be ignored, so the main heat dissipation is convection heat dissipation between the battery surface and the coolant. This heat transfer method is mainly related to the cooling system of the power station. For example, if the coolant is air, the heat dissipation is convection heat dissipation between the battery surface and the air.

[0054] Combining the heat generation and heat transfer of the above batteries, the heat conservation equation is as follows:

[0055] During charging:

[0056] During discharge:

[0057] in, Is the temperature change rate during the charging process, that is, the charging temperature change rate T' 充电 ;q 充电生热 is the heat generation rate of the charging process, the amount of heat generated per unit time during the charging process Q 充电 Divide by the cell volume to get; q 充电传热 is the heat transfer rate during the charging process, k is the thermal conductivity of the battery (W / (mK)); similarly, is the temperature change rate during the discharge process, that is, the discharge temperature change rate T' 放电 ;q 放电生热 is the heat generation rate of the discharge process, the amount of heat generated per unit time during the discharge process Q 放电 Divide by the cell volume V to get; q 放电传热 is the heat transfer rate during the discharge process. The temperature T 充电 、T 放电 is the Kelvin temperature. r is the equivalent internal resistance of the battery.

[0058] The heat during the equivalent charge and discharge period can be expressed as Formula 1:

[0059]

[0060] The right side of formula 1 is the heat lost during the equivalent charging and discharging process.

[0061] Further sorting out the formula 2:

[0062] The temperature change rate of the charging period can be obtained based on the temperature change in the operating data of the charging period in the equivalent charging and discharging period. According to the charging current in the operation data of the charging period in the equivalent charging and discharging period, the average charging current I of the charging period can be obtained. 充电 The temperature change rate of the discharge period can be obtained according to the temperature change in the operating data of the discharge period in the equivalent charge and discharge period. According to the discharge current in the operating data of the discharge period in the equivalent charge and discharge period, the average discharge current I of the discharge period can be obtained. 放电 , and then according to the above formula 2, the equivalent internal resistance of the battery module during the above equivalent charge and discharge period is obtained.

[0063] Under constant current conditions, the charging current or discharging current at each sampling moment is stable, I 充电 The charging current at a certain sampling moment or the average of the charging currents at all sampling moments in the charging period during the equivalent charging and discharging period can be taken, I放电 The discharge current at a certain sampling moment or the average value of the discharge current at all sampling moments in the discharge period in the equivalent charge and discharge period can be taken.

[0064] Under frequency modulation conditions, the current changes with time, I 充电 Equal to the total current flowing through the battery during the charging period of the equivalent charge and discharge period divided by the accumulated charging time; I 放电 It is equal to the total current flowing through the battery during the discharge period of the equivalent charge and discharge period divided by the accumulated discharge time.

[0065] For example, assume a charging process as follows: 1) Time interval 1: charging current is 2 amps, lasting 0.5 hours; 2) Time interval 2: charging current is 3 amps, lasting 1 hour; 3) Time interval 3: charging current is 2.5 amps, lasting 0.5 hours. Then: the total current flowing through the battery during this charging process = (2A×0.5h)+(3A×1h)+(2.5A×0.5h)=5.25 ampere-hours, the cumulative charging time = 0.5h+1h+0.5h=2h, I 充电 =5.25 ampere-hours / 2 hours = 2.625 amperes. 放电 The calculation is similar.

[0066] This embodiment provides a method for calculating the equivalent internal resistance of a battery module based on the heat loss during the battery module's charge and discharge process. This method can calculate the equivalent internal resistance of a battery module under different operating conditions based on the data collected by the power station. It is suitable for calculating internal resistance under various operating conditions. By detecting the internal resistance, power station operators can better manage and optimize the battery system. Changes in battery module temperature

[0067] In one embodiment, it further includes:

[0068] Step S500 calculates the internal resistance of each single cell in the battery module according to the equivalent internal resistance r of the battery module.

[0069] In one embodiment, step S500 includes:

[0070] Step S510 obtains the correlation coefficient c between the voltage and temperature change of the ith single cell of the battery module. i ;

[0071] Step S520 calculates the internal resistance r of the i-th single cell in the battery module according to the following formula: i :r i =c i ×r; where r is the equivalent internal resistance of the battery module.

[0072] Batteries have a strong correlation between voltage and internal resistance. Therefore, by analyzing the correlation coefficient between the voltage and temperature of the i-th cell in a battery module, the internal resistance of that cell can be calculated.

[0073] In one embodiment, the charging temperature change rate is calculated based on the operating data of the charging period in the equivalent charging and discharging period, including:

[0074] Obtaining a temperature change in the charging period during the equivalent charging and discharging period according to the temperature at the start sampling moment and the temperature at the end sampling moment of the charging period during the equivalent charging and discharging period;

[0075] The charging temperature change rate is obtained by dividing the temperature change amount of the charging period in the equivalent charging and discharging period by the duration of the charging period in the equivalent charging and discharging period.

[0076] The discharge temperature change rate is calculated based on the operating data of the discharge period in the equivalent charge and discharge period, including:

[0077] Obtaining a temperature change during the discharge period in the equivalent charge and discharge period according to the temperature at the start sampling moment and the temperature at the end sampling moment of the discharge period in the equivalent charge and discharge period;

[0078] The discharge temperature change rate is obtained by dividing the temperature change amount during the discharge period in the equivalent charge and discharge period by the duration of the discharge period in the equivalent charge and discharge period.

[0079] For example, assuming that the period of time when the battery module is charged from SOC1 to SOC2 is recorded as a charging period, the corresponding discharging period is the period of time when the battery module is discharged from SOC2 to SOC1, and the two constitute equivalent charging and discharging periods.

[0080] Charging temperature change rate It can be approximately equal to the temperature change when charging from SOC1 to SOC2 / the duration of charging from SOC1 to SOC2.

[0081] Discharge temperature change rate It can be approximately equal to the temperature change when discharging from SOC2 to SOC1 / the duration of discharging from SOC2 to SOC1.

[0082] In one embodiment, if the operating data of the battery module contains multiple equivalent charge and discharge time periods, the equivalent internal resistance of the battery module in the corresponding time period is calculated based on the operating data of each equivalent charge and discharge time period; the equivalent internal resistance of the battery module in multiple equivalent charge and discharge time periods is averaged to obtain the average equivalent internal resistance of the battery module.

[0083] For example, for Figure 3The equivalent charge and discharge period of SOC = 53% to 90% shown above can also be divided into two sections, such as 53% to 70% and 70% to 90%. The equivalent internal resistance is calculated for each section respectively, and then the equivalent internal resistance of the two sections is averaged to obtain the equivalent internal resistance of the 53% to 90% period.

[0084] In one embodiment of the present invention, Figure 2 As shown, a battery equivalent internal resistance estimation device includes:

[0085] The data acquisition module 100 is used to acquire the operating data of the battery module, the operating data including the sampling time and the state of charge (SOC), current and temperature of the battery module at the sampling time;

[0086] A data screening module 200 is used to screen out operation data of equivalent charge and discharge periods from the operation data, where the equivalent charge and discharge period consists of a pair of charge period and discharge period with the same SOC change;

[0087] The internal resistance calculation module 300 is used to calculate the charging temperature change rate and the average charging current according to the operating data of the charging period in the equivalent charging and discharging period, and calculate the discharge temperature change rate and the average discharge current according to the operating data of the discharge period in the equivalent charging and discharging period; according to the charging temperature change rate T' 充电 , average charging current I 充电 , discharge temperature change rate T' 放电 and the average discharge current I 放电 , calculate the equivalent internal resistance r of the battery module during the equivalent charge and discharge period according to the following formula:

[0088]

[0089] Where ρ is the density of the battery module, C p Where η is the equivalent specific heat of the battery module, k is the thermal conductivity of the battery module, and V is the volume of the battery module. Parameters such as density, equivalent specific heat, and thermal conductivity can be obtained in advance from the battery manufacturer.

[0090] In one embodiment, the internal resistance calculation module is further configured to calculate the internal resistance of each single cell in the battery module based on the equivalent internal resistance r of the battery module.

[0091] In one embodiment, the internal resistance calculation module is further used to obtain the correlation coefficient c between the voltage and temperature change of the i-th single cell of the battery module i ; Calculate the internal resistance r of the i-th single cell in the battery module according to the following formula i :r i =c i ×r; where r is the equivalent internal resistance of the battery module.

[0092] In one embodiment, the internal resistance calculation module is further used to obtain the temperature change of the charging period in the equivalent charging and discharging period based on the temperature at the start sampling moment and the temperature at the end sampling moment of the charging period in the equivalent charging and discharging period; divide the temperature change of the charging period in the equivalent charging and discharging period by the duration of the charging period in the equivalent charging and discharging period to obtain the charging temperature change rate; obtain the temperature change of the discharge period in the equivalent charging and discharging period based on the temperature at the start sampling moment and the temperature at the end sampling moment of the discharge period in the equivalent charging and discharging period; and divide the temperature change of the discharge period in the equivalent charging and discharging period by the duration of the discharge period in the equivalent charging and discharging period to obtain the discharge temperature change rate.

[0093] In one embodiment, the internal resistance calculation module is also used to calculate the equivalent internal resistance of the battery module in the corresponding period based on the operating data of each equivalent charge and discharge period if there are multiple equivalent charge and discharge period periods in the operating data of the battery module; and calculate the average equivalent internal resistance of the battery module based on the equivalent internal resistance of the battery module in multiple equivalent charge and discharge period periods.

[0094] It should be noted that the embodiments of the battery equivalent internal resistance estimation device provided by the present invention and the aforementioned embodiments of the battery equivalent internal resistance estimation method are based on the same inventive concept and can achieve the same technical effects. Therefore, for other specific details of the embodiments of the battery equivalent internal resistance estimation device, reference can be made to the description of the aforementioned embodiments of the battery equivalent internal resistance estimation method.

[0095] One embodiment of the present invention, as Figure 4 As shown, a battery equivalent internal resistance estimation device includes:

[0096] a memory 10 for storing a computer program 20;

[0097] The processor 30 is configured to implement the battery equivalent internal resistance estimation method described in any of the aforementioned embodiments when running the computer program 20.

[0098] The memory 10 may be any internal storage unit and / or external storage device capable of storing data and programs, for example, a plug-in hard disk, a smart memory card (SMC), a secure digital (SD) card, or a flash memory card.

[0099] As needed, the processor 10 can be a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a general-purpose processor or other logic devices, etc.

[0100] One embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When executed by a processor, the computer program can implement the battery equivalent internal resistance estimation method described in the aforementioned embodiment. That is, when part or all of the technical solution contributing to the prior art in the aforementioned embodiment of the present invention is embodied in the form of a computer software product, the aforementioned computer software product is stored in a computer-readable storage medium. The computer-readable storage medium can be any physical device or equipment capable of carrying computer program code. For example, a USB flash drive, a removable disk, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, etc.

[0101] It should be noted that the above embodiments can be freely combined as needed. The above description is only a preferred embodiment of the present invention. It should be pointed out that those skilled in the art can make several improvements and modifications without departing from the principles of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for estimating equivalent internal resistance of a battery, characterized in that: include: Acquire operating data of the battery module, the operating data including the state of charge (SOC), charging current, and temperature of the battery module at various sampling moments during the charging process, and the state of charge (SOC), discharging current, and temperature at various sampling moments during the discharging process; Filtering out operation data of an equivalent charge and discharge period from the operation data of the battery module, wherein the equivalent charge and discharge period consists of a pair of a charge period and a discharge period with the same SOC change; Calculating a charge temperature change rate and an average charge current based on the operation data of the charge period in the equivalent charge and discharge period, and calculating a discharge temperature change rate and an average discharge current based on the operation data of the discharge period in the equivalent charge and discharge period; According to the charging temperature change rate T' 充电 , average charging current I 充电 , discharge temperature change rate T' 放电 and the average discharge current I 放电 , calculate the equivalent internal resistance r of the battery module during the equivalent charge and discharge period according to the following formula: Wherein, ρ is the density of the battery module, C p is the equivalent specific heat capacity of the battery module, k is the thermal conductivity of the battery module, and V is the volume of the battery module.

2. The battery equivalent internal resistance estimation method according to claim 1, characterized in that: Also includes: The internal resistance of each single cell in the battery module is calculated based on the equivalent internal resistance r of the battery module.

3. The battery equivalent internal resistance estimation method according to claim 2, characterized in that: Obtain the correlation coefficient c between the voltage and temperature change of the ith single cell of the battery module i ; The internal resistance r of the i-th single cell in the battery module is calculated according to the following formula: i : r i ＝c i ×r； Wherein, r is the equivalent internal resistance of the battery module.

4. The method for estimating the equivalent internal resistance of a battery according to claim 1, wherein: Calculating the charging temperature change rate according to the operation data of the charging period in the equivalent charging and discharging period includes: Obtaining a temperature change in the charging period of the equivalent charging and discharging period according to the temperature at the start sampling moment and the temperature at the end sampling moment of the charging period of the equivalent charging and discharging period; The charging temperature change rate is obtained by dividing the temperature change amount of the charging period in the equivalent charging and discharging period by the duration of the charging period in the equivalent charging and discharging period; Calculating the discharge temperature change rate according to the operating data of the discharge period in the equivalent charge and discharge period includes: Obtaining a temperature change during the discharge period of the equivalent charge and discharge period according to the temperature at the start sampling moment and the temperature at the end sampling moment of the discharge period of the equivalent charge and discharge period; The discharge temperature change rate is obtained by dividing the temperature change amount of the discharge period in the equivalent charge and discharge period by the duration of the discharge period in the equivalent charge and discharge period.

5. The battery equivalent internal resistance estimation method according to claim 1, characterized in that: If the operating data of the battery module includes multiple equivalent charge and discharge time periods, calculating the equivalent internal resistance of the battery module in the corresponding time period according to the operating data of each equivalent charge and discharge time period; The average equivalent internal resistance of the battery module is calculated according to the equivalent internal resistance of the battery module in multiple equivalent charge and discharge time periods.

6. The method for estimating the equivalent internal resistance of a battery according to claim 1, wherein: The operating data of the battery module is obtained from the operating data collected from the power station.

7. A battery equivalent internal resistance estimation device, characterized in that: include: a data acquisition module, configured to acquire operating data of the battery module, the operating data including the state of charge (SOC), charging current, and temperature of the battery module at various sampling moments during the charging process, and the state of charge (SOC), discharge current, and temperature of the battery module at various sampling moments during the discharging process; a data screening module, configured to screen out operating data of an equivalent charge and discharge period from the operating data of the battery module, wherein the equivalent charge and discharge period consists of a pair of a charge period and a discharge period with the same SOC change; The internal resistance calculation module is used to calculate the charging temperature change rate and the average charging current according to the operating data of the charging period in the equivalent charging and discharging period, and calculate the discharge temperature change rate and the average discharge current according to the operating data of the discharge period in the equivalent charging and discharging period; according to the charging temperature change rate T' 充电 , average charging current I 充电 , discharge temperature change rate T' 放电 and the average discharge current I 放电 , calculate the equivalent internal resistance r of the battery module during the equivalent charge and discharge period according to the following formula: Wherein, ρ is the density of the battery module, C p is the equivalent specific heat capacity of the battery module, k is the thermal conductivity of the battery module, and V is the volume of the battery module.

8. The battery equivalent internal resistance estimation device according to claim 7, characterized in that: The internal resistance calculation module is further used to calculate the internal resistance of each single cell in the battery module according to the equivalent internal resistance r of the battery module.

9. A battery equivalent internal resistance estimation device, characterized in that: include: memory for storing computer programs; A processor, configured to implement the battery equivalent internal resistance estimation method according to any one of claims 1 to 6 when running the computer program.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the battery equivalent internal resistance estimation method according to any one of claims 1 to 6 is implemented.

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