Battery internal resistance detection circuit

Abstract

The utility model discloses a battery internal resistance detection circuit, a battery comprises at least one battery piece, and the battery internal resistance detection circuit comprises a current acquisition module, a measurement module and a calculation module. The current acquisition module is connected to a charging and discharging loop of the battery and is used for acquiring current on the charging and discharging loop of the battery; the measurement module is connected with the current acquisition module and the battery piece and is used for measuring the current component of the charging and discharging current of the battery in a preset frequency band and the voltage component of the charging and discharging voltage of the battery piece in the preset frequency band; the calculation module is connected with the measurement module and is used for determining the internal resistance of the battery piece according to the current component of the preset frequency band and the voltage component of the preset frequency band. According to the technical scheme provided by the embodiment of the utility model, the measurement module can detect the current component of the preset frequency band and the voltage component of the preset frequency band in the charging and discharging process of the battery in real time, interference of other signals in the voltage signal and the current signal can be avoided, and the measurement precision of the internal resistance of the battery piece can be further improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technical field especially relates to a battery internal resistance detection circuit. BACKGROUND

[0002] The internal resistance is the resistance that the current flows through the inside of the battery when the battery is working. The battery internal resistance is an important parameter for identifying the quality of lithium ion battery. If the battery internal resistance is large, a large amount of Joule heat will be generated, causing the battery temperature to rise, resulting in the decrease of the battery discharge working voltage and the shortening of the discharge time, which will seriously affect the battery performance and service life. Therefore, in the verification of the electrochemical performance test of lithium battery under various factors, the internal resistance is also an important investigation parameter.

[0003] The prior art usually obtains test data after a large number of tests on the battery based on a data model, and then estimates the current internal resistance of the battery according to the test data, so the measurement accuracy is low. UTILITY MODEL CONTENTS

[0004] The utility model provides a kind of battery internal resistance detection circuit to improve the detection accuracy of battery internal resistance.

[0005] According to the utility model provides a kind of battery internal resistance detection circuit, the battery includes at least one battery piece;The battery internal resistance detection circuit includes current acquisition module, measurement module and computing module;

[0006] The current acquisition module is connected on the charge-discharge circuit of the battery, and the current acquisition module is used to acquire the current on the charge-discharge circuit of the battery;The measurement module is connected with the current acquisition module and the battery piece, and the measurement module is used to measure the current component of the charge-discharge current of the battery in the preset frequency band and the voltage component of the charge-discharge voltage of the battery piece in the preset frequency band;The computing module is connected with the measurement module, and the computing module is used to determine the internal resistance of the battery piece according to the current component of the preset frequency band and the voltage component of the preset frequency band.

[0007] Optionally, the measurement module includes first switch phase detector and second switch phase detector;

[0008] The input end of the first switch phase detector is connected with the current acquisition module, the output end of the first switch phase detector is connected with the computing module, and the first switch phase detector is used to measure the current component of the charge-discharge current of the battery in the preset frequency band.

[0009] The input end of the second switch phase detector is connected with the battery piece, and the output end of the second switch phase detector is connected with the computing module, and the second switch phase detector is used to measure the voltage component of the charge-discharge voltage of the battery piece in the preset frequency band.

[0010] Optionally, the second switch phase detector is connected with the battery piece one by one.

[0011] Optionally, the battery internal resistance detection circuit further comprises a variable frequency signal generator; the variable frequency signal generator is connected with the current collection module in series on the charge-discharge circuit of the battery.

[0012] The variable frequency signal generator is used for frequency conversion of the charging signal when the battery is charging, and outputs a current of a preset frequency.

[0013] Optionally, the battery internal resistance detection circuit further comprises a control circuit, the control circuit is connected with the variable frequency signal generator, and the control circuit is used for controlling the preset frequency of the current output by the variable frequency signal generator.

[0014] Optionally, the battery internal resistance detection circuit further comprises a control module, the control module is connected with the calculation module, and the control module is used for controlling the calculation module to select a preset algorithm to calculate the internal resistance of the battery piece according to the current component of the preset frequency band and the voltage component of the preset frequency band measured by the measurement module.

[0015] Optionally, the current collection module comprises a current transformer, and the current transformer is used for collecting an alternating current component in the charge-discharge signal of the battery.

[0016] Optionally, the battery internal resistance detection circuit further comprises a filtering module; an input end of the filtering module is connected with an output end of the first switch phase detector and an output end of the second switch phase detector, and an output end of the filtering module is connected with the calculation module; the filtering module is used for filtering out alternating current components in the output signals of the first switch phase detector and the second switch phase detector.

[0017] Optionally, the battery internal resistance detection circuit further comprises a sampling module, the sampling module is connected between the measurement module and the calculation module, the sampling module samples the signal output by the measurement module, and the calculation module determines the internal resistance of the battery piece according to the sampling signal.

[0018] Optionally, the sampling module comprises an analog-digital conversion unit, the analog-digital conversion unit is used for converting the signal output by the measurement module into a digital quantity and outputting to the calculation module.

[0019] The analog-digital conversion unit is a multi-channel analog-digital conversion unit.

[0020] The technical scheme of the embodiment of the utility model discloses, through setting up the current acquisition module is connected on the charge-discharge circuit of battery, and setting up the measuring module is connected with current acquisition module, battery piece respectively, make the measuring module can real -time measurement preset frequency band's current component and preset frequency band's voltage component in the process of battery charge-discharge, and the calculation module calculates the internal resistance of battery piece according to the measurement data of measuring module output, thereby can when calculating the internal resistance of battery piece, can avoid the interference of other signals in voltage signal and current signal, and then can promote the measurement accuracy of battery piece internal resistance, and, when calculating the internal resistance of battery piece, can realize the on -line detection of internal resistance, make the internal resistance of measurement can with the current state of battery piece matches, thereby can further promote the accuracy and stability of calculating the internal resistance of battery, simultaneously, through real -time detection and accurate calculation internal resistance, can find the problem of battery in time, and take preventive maintenance measures, avoid the maintenance cost and downtime caused by battery failure, help to reduce the maintenance cost of system, improve the operation efficiency and economy of system.

[0021] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the utility model, nor is it used to limit the scope of the utility model. Other features of the utility model will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme in the embodiments of the utility model, the drawings needed in the embodiment description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to these drawings without creating labor.

[0023] Figure 1 The structural schematic diagram of a battery internal resistance detection circuit provided by the embodiment of the utility model is shown in the figure;

[0024] Figure 2 The structural schematic diagram of another battery internal resistance detection circuit provided by the embodiment of the utility model is shown in the figure;

[0025] Figure 3 The structural schematic diagram of another battery internal resistance detection circuit provided by the embodiment of the utility model is shown in the figure;

[0026] Figure 4 The structural schematic diagram of another battery internal resistance detection circuit provided by the embodiment of the utility model is shown in the figure;

[0027] Figure 5 The structural schematic diagram of another battery internal resistance detection circuit provided by the embodiment of the utility model is shown in the figure;

[0028] Figure 6The utility model discloses a structure schematic drawing of another battery internal resistance detection circuit for the embodiment of the utility model provides.

[0029] Figure 7 The utility model discloses a structure schematic drawing of another battery internal resistance detection circuit for the embodiment of the utility model provides. DETAILED DESCRIPTION

[0030] In order to make the personnel in the technical field better understand the utility model scheme, below will combine the drawing in the embodiment of the utility model, and the technical scheme in the embodiment of the utility model is clearly and completely described, obviously, the described embodiment only is the embodiment of a part of the utility model, and is not all the embodiment. Based on the embodiment in the utility model, all other embodiments that the ordinary skill in the art obtains without making the creative labor should belong to the range of the utility model protection.

[0031] It needs to be explained that the terms "first", "second" and the like in the specification and claims of the utility model and the above-mentioned drawing are used for distinguishing similar objects, and do not have to be used for describing specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiment of the utility model described here can be implemented in the order other than those illustrated or described here. In addition, the terms "include" and "have" and their any modification, are intended to cover the non-exclusive inclusion, for example, the process, method, system, product or equipment including a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0032] Figure 1 The utility model discloses a structure schematic drawing of battery internal resistance detection circuit for the embodiment of the utility model provides, reference Figure 1 , battery 1 includes at least one battery piece, for example, battery 1 includes one battery piece in the embodiment of the utility model;Battery internal resistance detection circuit includes current acquisition module 2, measurement module 3 and calculation module 4;Current acquisition module 2 is connected on the charge-discharge circuit of battery, and current acquisition module 2 is used to acquire the current on the charge-discharge circuit of battery;Measurement module 3 is connected with current acquisition module 2 and battery piece, and measurement module 3 is used to measure the current component of the charge-discharge current of battery in the preset frequency band and the voltage component of the charge-discharge voltage of battery piece in the preset frequency band;Calculation module 4 is connected with measurement module 3, and the calculation module is used to determine the internal resistance of battery piece according to the current component of the preset frequency band and the voltage component of the preset frequency band.

[0033] The power module 5 can be connected to the battery charging and discharging circuit to process the charging and discharging current and voltage of the battery and connect to external devices to realize the charging and discharging of the battery. For example, during the charging of the battery, the power module 5 can include an AC-DC, the DC end of the AC-DC is connected to the battery, and the AC end can be connected to the power grid or other AC power. The power grid or other AC power can charge the battery through the AC-DC. Alternatively, the power module 5 can also include a DC-DC, the input DC end of the DC-DC can be connected to DC power, and the output DC end of the DC-DC is connected to the battery. The DC power can charge the battery through the DC-DC. During the discharging of the battery, the power module 5 can include an AC-DC, the DC end of the AC-DC is connected to the battery, and the AC end can be connected to the power grid or other AC power. The battery can discharge through the AC-DC. Alternatively, the power module 5 can also include a DC-DC, the input DC end of the DC-DC can be connected to DC power, and the output DC end of the DC-DC is connected to the battery. The battery can discharge through the DC-DC.

[0034] Specifically, during the charging and discharging of the battery, the charging and discharging current and voltage of the battery contain a large number of harmonics distributed in multiple frequency bands, that is, an AC current component with an amplitude much smaller than that of the DC current. Therefore, the current collected by the current collection module 2 contains AC current components in multiple frequency bands. Since the current collection module 2 is connected to the measurement module 3, the measurement module 3 can measure the current component in the preset frequency band. The preset frequency band can refer to a frequency range with a frequency less than a preset value and a current peak greater than a preset value. When the charging and discharging current of the battery flows through the battery sheet, the voltage of the battery sheet also contains a large number of harmonics distributed in multiple frequency bands. Similarly, since the battery is connected to the measurement module 3, the measurement module 3 can measure the voltage component in the preset frequency band. The preset frequency band can refer to a frequency range with a frequency less than a preset value and a voltage peak greater than a preset value. Then the measurement module 3 inputs the measured current component in the preset frequency band and the voltage component in the preset frequency band to the calculation module 4, so that the calculation module 4 calculates the current internal resistance of the battery sheet according to the input measurement data.

[0035] The technical scheme of the embodiment of the utility model discloses, through setting up current acquisition module 2 is connected on the charge-discharge circuit of battery 1, and setting up measurement module 3 is connected with current acquisition module 2, battery piece respectively, make battery charge-discharge process measurement module 3 can real-time measurement preset frequency band's current component and preset frequency band's voltage component, and the internal resistance of battery piece is calculated by the calculation module 4 according to the measurement data output by measurement module, thereby can when calculating the internal resistance of battery piece, the interference of other signals in voltage signal and current signal can be avoided, and then the measurement precision of the internal resistance of battery piece can be improved.Moreover, when calculating the internal resistance of battery piece, the on-line detection of internal resistance can be realized, so that the internal resistance measured can match the current state of battery piece, thereby the accuracy and stability of calculating the internal resistance of battery can be further improved.Meanwhile, through real-time detection and accurate calculation of internal resistance, the problem of battery can be found in time, and preventive maintenance measures are taken, the maintenance cost and downtime caused by battery failure are avoided, which helps to reduce the maintenance cost of system and improve the operation efficiency and economy of system.

[0036] Figure 2 Another battery internal resistance detection circuit structure schematic diagram provided by the embodiment of the utility model is provided with reference to Figure 2 On the basis of the above embodiment, battery 1 can include two battery pieces 11, and measurement module 3 includes first switch phase detector 301 and second switch phase detector 302; the input end of first switch phase detector 301 is connected with current acquisition module 2, the output end of first switch phase detector 301 is connected with calculation module 4, and first switch phase detector 301 is used to measure the current component of the charge-discharge current of battery in a preset frequency band; the input end of second switch phase detector 302 is connected with a battery piece 11, and the output end of second switch phase detector 302 is connected with calculation module 4, and second switch phase detector 302 is used to measure the voltage component of the charge-discharge voltage of battery piece 11 in a preset frequency band.

[0037] Specifically, in the charge-discharge process of battery, the current collected by current acquisition module 2 contains alternating current components of multiple frequency bands, and the alternating current components are input to first switch phase detector 301, and then first switch phase detector 301 measures the current component of the preset frequency band of the alternating current components, and the current component measured by first switch phase detector 301 is composed of a direct current term and a 2-frequency alternating current term, and similarly, the voltage component measured by second switch phase detector 302 is composed of a direct voltage term and a 2-frequency alternating voltage term. First switch phase detector 301 and second switch phase detector 302 input the measurement data to calculation module 4 respectively, so that calculation module 4 calculates the internal resistance of battery piece 11 according to the input measurement data.

[0038] The technical scheme provided by the embodiment is characterized in that the first switch phase detector 301 is connected with the current collection module 2, and the second switch phase detector 302 is connected with the battery piece 11, so that the first switch phase detector 301 can measure the current component of the preset frequency band of the current collected by the current collection module 2, and the second switch phase detector 302 can measure the voltage component of the preset frequency band corresponding to the voltage of the battery piece 11, thereby reducing the interference of signals in other frequency bands in the current signal and the voltage signal, and improving the collection accuracy of the current component and the voltage component.

[0039] With reference to the foregoing Figure 2 Optionally, the second switch phase detector 302 is connected with the battery piece 11 in one-to-one correspondence.

[0040] Optionally, the measurement module 3 can include two second switch phase detectors 302, and the output ends of the second switch phase detectors 302 are connected with the calculation module 4.

[0041] Specifically, in the charging and discharging process of the battery, the second switch phase detector 302 measures the voltage component corresponding to the battery piece 11 and inputs the voltage component to the calculation module 4, so that the calculation module 4 can calculate the internal resistance of each battery piece 11.

[0042] The technical scheme provided by the embodiment is characterized in that the second switch phase detector 302 is connected with the battery piece 11 in one-to-one correspondence, so that the second switch phase detector 302 can measure the voltage component of the preset frequency band in the voltage corresponding to the battery piece 11, thereby improving the collection accuracy and efficiency.

[0043] Figure 3 Another structural schematic diagram of a battery internal resistance detection circuit provided by the utility model embodiment, with reference to Figure 3 On the basis of the above-mentioned embodiments, the battery internal resistance detection circuit further includes a control module 6 connected with the calculation module 4, and the control module 6 is used for controlling the calculation module 4 to select a preset algorithm to calculate the internal resistance of the battery piece 11 according to the current component of the preset frequency band and the voltage component of the preset frequency band measured by the measurement module 3.

[0044] Optionally, the preset algorithm can include multiple, and the control module 6 selects the preset algorithm according to the different control calculation modules 4 of the current and voltage measured by the measurement module 3. Exemplarily, if the current and voltage measured by the measurement module 3 are in the form of alternating current, the selected preset algorithm can be to divide the voltage effective value by the current effective value, and then multiply the cosine of the phase angle, and then calculate the internal resistance of the battery; if the current and voltage measured by the measurement module 3 are in the form of direct current in two specific time intervals, respectively, the selected preset algorithm can be to calculate the internal resistance of the battery by calculating the change of the voltage and the current, and using Ohm's law; if the current and voltage measured by the measurement module 3 include direct current, the selected preset algorithm can calculate the internal resistance of the battery according to the direct current by using Ohm's law.

[0045] Specifically, in the charging and discharging process of the battery, the first switch phase detector 301 inputs the measured current direct current item and 2 times frequency current alternating current item to the calculation module 4, and the second switch phase detector 302 inputs the measured voltage direct current item and 2 times frequency voltage alternating current item to the calculation module 4, and further, the control module 6 outputs a control signal, and the calculation module 4 responds to the control signal to calculate the internal resistance of the battery piece 11 according to the direct current item in the current component and the voltage component by the preset algorithm.

[0046] The technical scheme provided by the embodiment, by setting the control module 6 to control the calculation module 4, so that the control module 6 can control the calculation module 4 to select the most suitable algorithm for internal resistance calculation according to different application requirements and battery types, thereby realizing more accurate results.

[0047] Figure 4 Another structure diagram of the battery internal resistance detection circuit provided by the utility model embodiment, refer to Figure 4 On the basis of the above-mentioned embodiments, the current acquisition module 2 includes a current transformer, and the current transformer is used to acquire the alternating current component in the charging and discharging signal of the battery.

[0048] Specifically, in the charging and discharging process of the battery, the current transformer inputs the acquired alternating current component in the charging and discharging loop of the battery to the first switch phase detector 301, and then the first switch phase detector 301 measures the current component in the preset frequency band and inputs the current component to the calculation module 4.

[0049] The technical scheme provided by the embodiment, by setting the current transformer to acquire the alternating current component in the current signal, the charging and discharging process of the battery can be monitored in real time, and the data accuracy and precision are improved.

[0050] Figure 5 Another structure diagram of the battery internal resistance detection circuit provided by the utility model embodiment, refer to Figure 5On the basis of the above embodiments, the battery internal resistance detection circuit further comprises a filtering module 7; an input end of the filtering module 7 is connected with an output end of the first switch phase detector 301 and an output end of the second switch phase detector 302, and an output end of the filtering module 7 is connected with the calculation module 4, and the filtering module 7 is used for filtering out alternating current components in the output signals of the first switch phase detector 301 and the second switch phase detector 302.

[0051] Optionally, the filtering module 7 is connected with the output end of the first switch phase detector 301 and the output end of the second switch phase detector 302.

[0052] Specifically, during the charging and discharging process of the battery, since the filtering module 7 is connected with the first switch phase detector 301 and the second switch phase detector 302 respectively, the filtering module 7 can filter out 2 times frequency alternating current in the current component of the preset frequency band measured by the first switch phase detector 301 and can filter out 2 times frequency alternating voltage in the voltage component of the preset frequency band measured by the second switch phase detector 302, so that the current and voltage output by the filtering module 7 are all direct current. For example, the filtering module 7 can comprise a low-pass filter unit for filtering out high-frequency components and noise in the signal.

[0053] The technical scheme provided in the embodiment can reduce measurement error and improve the accuracy and reliability of internal resistance detection by setting the filtering module 7 to filter out alternating current components in the output signals of the first switch phase detector 301 and the second switch phase detector 302. Meanwhile, after the filtering module 7 filters out 2 times frequency alternating current, the output signal is smoother and more stable and is easier to be processed or analyzed.

[0054] Figure 6 Another structure schematic diagram of a battery internal resistance detection circuit provided in the embodiment of the utility model, refer to Figure 6 On the basis of the above embodiments, the battery internal resistance detection circuit further comprises a sampling module 8, the sampling module 8 is connected between the measurement module 3 and the calculation module 4, the sampling module 8 samples the signal output by the measurement module 3, and the calculation module 4 determines the internal resistance of the battery piece according to the sampling signal.

[0055] Optionally, the measurement module 3 comprises a first switch phase detector 301 and a second switch phase detector 302, the battery internal resistance detection circuit further comprises a filtering module 7, an input end of the filtering module 7 is connected with an output end of the first switch phase detector 301 and an output end of the second switch phase detector 302, and an input end of the filtering module 7 is connected with the calculation module 4.

[0056] Optionally, the sampling module 8 is connected with the control module 6 and is used for sampling the output signals of the first switch phase detector 301 and the second switch phase detector 302 in response to the control signal of the control module 6.

[0057] Specifically, during the charging and discharging process of the battery, the control module 6 outputs a control signal to the sampling module 8, and then the sampling module 8 converts the direct current and the direct voltage output by the filtering module 7 into digital quantities through an analog-digital conversion unit in response to the control signal, so that the calculation module 4 calculates the internal resistance of the battery sheet 11. Through this setting, the accuracy and reliability of signal processing can be improved.

[0058] With reference to the foregoing Figure 6 Optionally, the sampling module 8 comprises an analog-digital conversion unit, which is configured to convert the signal output by the measuring module into a digital quantity and output to the calculation module; wherein the analog-digital conversion unit is a multi-channel analog-digital conversion unit.

[0059] Specifically, during the charging and discharging process of the battery, the multi-channel analog-digital conversion unit is configured to input the channel gating of the current output in the battery charging and discharging circuit and the calculation module 4, output the current to the calculation module 4, and input the voltage output of the battery sheet 11 to be calculated and the calculation module 4, and then output the corresponding voltage of the battery sheet 11 to the calculation module 4, so that the calculation module 4 calculates the internal resistance of the corresponding battery sheet. Through this setting, the calculation module 4 can accurately monitor and obtain the current in the battery charging and discharging circuit and the voltage of each battery sheet 11, thereby improving the internal resistance detection accuracy.

[0060] Figure 7 Another structure diagram of a battery internal resistance detection circuit is provided for the embodiments of the utility model, with reference to Figure 7 On the basis of the above embodiments, the battery 1 can comprise N battery sheets 11, and the battery internal resistance detection circuit further comprises a variable frequency signal generator 9; the variable frequency signal generator 9 is connected in series with the current collection module 2 on the charging and discharging circuit of the battery; the variable frequency signal generator 9 is configured to perform frequency conversion on the charging signal when the battery is charging, and output a current with a preset frequency.

[0061] Optionally, the measuring module 3 can comprise N second switch phase detectors 302, which are connected in one-to-one correspondence with the battery sheets 11, and the output ends of the second switch phase detectors 302 are connected with the filtering module 7.

[0062] Specifically, during the charging and discharging process of the battery, since the variable frequency signal generator 9 is connected with the current transformer, the current signal flowing into the current transformer can be controlled to be a current with a preset frequency, at this time, the first switch phase detector 301 and the second switch phase detector 302 are configured to frequency synchronization and then measure the current component and the voltage component with the preset frequency.

[0063] The technical scheme provided by the embodiment can automatically generate a current signal of a known frequency band, that is, a preset frequency band, so that the measurement data of the first and second switch phase detectors 301 and 302 are more accurate, and the internal resistance measurement precision is further improved.

[0064] With reference to the foregoing Figure 7 Optionally, the battery internal resistance detection circuit further comprises a control circuit 10, the control circuit 10 is connected with the variable frequency signal generator 9, and the control circuit 10 is configured to control the preset frequency of the current output by the variable frequency signal generator 9.

[0065] Optionally, the control circuit 10 is further connected with the control module 6.

[0066] Specifically, during the charging and discharging process of the battery, the control module 6 outputs a control signal to the control circuit 10, and the control circuit 10 controls the current output by the variable frequency signal generator 9 to be a current of the preset frequency in response to the control signal.

[0067] The technical scheme provided by the embodiment can ensure that the frequency of the current output by the variable frequency signal generator 10 is accurate and consistent with the preset value, and can further reduce the error between the output frequency of the variable frequency signal generator 10 and the preset frequency, thereby reducing the error rate of the system.

[0068] It should be understood that the various forms of flow shown above can be reordered, added or deleted. For example, the steps described in the present application can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical scheme of the present application can be achieved, and the present application does not limit this.

[0069] The above specific embodiments do not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A battery internal resistance detection circuit, characterized in that: The battery includes at least one battery cell; the battery internal resistance detection circuit includes a current acquisition module, a measurement module and a calculation module; The current acquisition module is connected to the charge and discharge circuit of the battery, and is used to collect the current in the charge and discharge circuit of the battery; the measurement module is connected to the current acquisition module and the battery cell, and is used to measure the current component of the charge and discharge current of the battery in a preset frequency band and the voltage component of the charge and discharge voltage of the battery cell in the preset frequency band; the calculation module is connected to the measurement module, and is used to determine the internal resistance of the battery cell based on the current component in the preset frequency band and the voltage component in the preset frequency band; Wherein, the measurement module includes a first switch phase detector and a second switch phase detector; The input end of the first switch phase detector is connected to the current acquisition module, the output end of the first switch phase detector is connected to the calculation module, and the first switch phase detector is used to measure the current component of the charge and discharge current of the battery in the preset frequency band; The input end of the second switch phase detector is connected to the battery cell, the output end of the second switch phase detector is connected to the calculation module, and the second switch phase detector is used to measure the voltage component of the charge and discharge voltage of the battery cell in the preset frequency band.

2. The battery internal resistance detection circuit according to claim 1, characterized in that: The second switch phase detector is connected to the battery slices in a one-to-one correspondence.

3. The battery internal resistance detection circuit according to claim 1, characterized in that: It also includes a frequency conversion signal generator; the frequency conversion signal generator and the current acquisition module are connected in series to the charge and discharge circuit of the battery; The variable frequency signal generator is used to perform frequency conversion on the charging signal when the battery is charging, and output a current of a preset frequency.

4. The battery internal resistance detection circuit according to claim 3, characterized in that: It also includes a control circuit, which is connected to the variable frequency signal generator and is used to control the preset frequency of the output current of the variable frequency signal generator.

5. The battery internal resistance detection circuit according to claim 1, characterized in that: It also includes a control module, which is connected to the calculation module. The control module is used to control the calculation module to select a preset algorithm to calculate the internal resistance of the battery cell based on the current component of the preset frequency band and the voltage component of the preset frequency band measured by the measurement module.

6. The battery internal resistance detection circuit according to claim 1, characterized in that: The current acquisition module includes a current transformer, which is used to acquire the AC component in the charge and discharge signal of the battery.

7. The battery internal resistance detection circuit according to claim 1, characterized in that: It also includes a filtering module; the input end of the filtering module is connected to the output end of the first switching phase detector and the output end of the second switching phase detector, the output end of the filtering module is connected to the calculation module, and the filtering module is used to filter out the AC components in the output signals of the first switching phase detector and the second switching phase detector.

8. The battery internal resistance detection circuit according to claim 1, characterized in that: It also includes a sampling module, which is connected between the measurement module and the calculation module. The sampling module samples the signal output by the measurement module to obtain a sampling signal. The calculation module determines the internal resistance of the battery cell according to the sampling signal.

9. The battery internal resistance detection circuit according to claim 8, characterized in that: The sampling module includes an analog-to-digital conversion unit, which is used to convert the signal output by the measurement module into a digital value and output it to the calculation module; Wherein, the analog-to-digital conversion unit is a multi-channel analog-to-digital conversion unit.

Images