Internal Resistance Detection Device and Internal Resistance Detection Method

Abstract

This application relates to an internal resistance detection device and an internal resistance detection method. The internal resistance detection device includes an internal resistance detection device and a signal relay device. The internal resistance detection device is connected to the signal relay device, and the signal relay device is used to connect to the target battery to be detected; the internal resistance detection device is used to output an initial detection signal to the signal relay device; the signal relay device includes a signal amplification circuit and a signal attenuation circuit. Among them, the signal amplification circuit is used to amplify the initial detection signal to obtain a target detection signal and output the target detection signal to the target battery; the signal attenuation circuit is used to collect the initial measurement signal of the target battery and perform signal attenuation processing on the initial measurement signal to obtain a target measurement signal; the internal resistance detection device is used to determine the internal resistance of the target battery according to the initial detection signal and the target measurement signal. Using this device for internal resistance detection can improve the signal-to-noise ratio of the measurement signal, thereby improving the accuracy of internal resistance detection.

Description

Technical Field

[0001] The present application relates to the technical field of battery internal resistance detection, and particularly to an internal resistance detection device and an internal resistance detection method. Background Art

[0002] As a power supply device, batteries are widely used in daily life. However, due to the gradual decline of battery performance during long-term use, it will affect the normal power supply of equipment and cause adverse effects. For example, for network communication equipment such as base stations and network communication equipment in communication machine rooms, when the power supply demand cannot be met, it may cause the interruption of network communication equipment, and then cause the interruption of the network. Therefore, it is usually necessary to inspect and maintain the batteries in network communication equipment.

[0003] Traditionally, a battery internal resistance detector is used to measure the internal resistance of a battery, and the performance and quality of the battery are analyzed based on the measured internal resistance value of the battery.

[0004] However, when using a traditional battery internal resistance detector to detect the internal resistance of a battery, if the battery is in a floating charge state, the collected test signal is extremely vulnerable to the interference of power supply ripple, resulting in a low signal-to-noise ratio of the test signal, and then the accuracy of the measured internal resistance value is poor. Summary of the Invention

[0005] Based on this, it is necessary to provide an internal resistance detection device and an internal resistance detection method that can improve the signal-to-noise ratio of the test signal and thus improve the accuracy of the battery internal resistance detection result for the above technical problems.

[0006] In a first aspect, the present application provides an internal resistance detection device. The internal resistance detection device includes an internal resistance detection device and a signal relay device. The internal resistance detection device is connected to the signal relay device, and the signal relay device is used to connect to a target battery to be detected;

[0007] The internal resistance detection device is configured to output an initial detection signal to the signal relay device;

[0008] The signal relay device includes a signal amplification circuit and a signal attenuation circuit. Among them, the signal amplification circuit is configured to amplify the initial detection signal to obtain a target detection signal and output the target detection signal to the target battery; the signal attenuation circuit is configured to collect the initial measurement signal of the target battery and perform signal attenuation processing on the initial measurement signal to obtain a target measurement signal;

[0009] The internal resistance detection device is configured to determine the internal resistance of the target battery according to the initial detection signal and the target measurement signal.

[0010] In one embodiment, the signal amplification circuit includes a plurality of first common-mode inductors. The primaries of the first common-mode inductors are connected in series, and the secondaries of the first common-mode inductors are connected in parallel.

[0011] The plurality of first common-mode inductors are used to amplify an initial detection signal to obtain a target detection signal.

[0012] In one embodiment, the first common-mode inductor is a 1:1 common-mode inductor; the amplification factor of the target detection signal is equal to the number of the plurality of first common-mode inductors.

[0013] In one embodiment, the signal amplification circuit further includes a first bidirectional diode; the first bidirectional diode is connected in parallel with the primaries of the plurality of first common-mode inductors;

[0014] The first bidirectional diode is used to suppress the instantaneous voltage of the target battery.

[0015] In one embodiment, the signal amplification circuit further includes a first isolation capacitor and a first discharge resistor; after the first isolation capacitor and the first discharge resistor are connected in series, they are connected in parallel with the secondaries of the plurality of first common-mode inductors; both ends of the first discharge resistor are respectively connected to the positive connection port and the negative connection port of the target battery;

[0016] The first isolation capacitor is used to isolate the DC voltage of the target battery;

[0017] The first discharge resistor is used to discharge the charge on the first isolation capacitor after the detection is completed.

[0018] In one embodiment, the negative terminals of the primaries of the plurality of first common-mode inductors and the negative terminals of the secondaries of the plurality of first common-mode inductors are connected in communication.

[0019] In one embodiment, the signal amplification circuit includes a transformer;

[0020] The transformer is used to amplify an initial detection signal to obtain a target detection signal.

[0021] In one embodiment, the signal amplification circuit further includes a second bidirectional diode; the second bidirectional diode is connected in parallel with the primary of the transformer;

[0022] The second bidirectional diode is used to suppress the instantaneous voltage of the target battery.

[0023] In one embodiment, the signal amplification circuit further includes a second isolation capacitor and a second discharge resistor; after the second isolation capacitor and the second discharge resistor are connected in series, they are connected in parallel with the secondary of the transformer; both ends of the second discharge resistor are respectively connected to the positive connection port and the negative connection port of the target battery;

[0024] A second isolation capacitor for isolating the DC voltage of the target battery;

[0025] A second discharge resistor for discharging the charge on the second isolation capacitor after the detection is completed.

[0026] In one embodiment, the negative extreme of the primary of the transformer is in communication with the negative extreme of the secondary of the transformer.

[0027] In one embodiment, the signal attenuation circuit includes a signal filtering sub-circuit and a signal attenuation sub-circuit;

[0028] The signal filtering sub-circuit is configured to collect an initial measurement signal of the target battery and perform signal filtering processing on the initial measurement signal to obtain an intermediate measurement signal;

[0029] The signal attenuation sub-circuit is configured to perform signal attenuation processing on the intermediate measurement signal to obtain a target measurement signal.

[0030] In one embodiment, the signal filtering sub-circuit includes a second common-mode inductor and filter capacitors; the filter capacitors include a first filter capacitor, a second filter capacitor, and a third filter capacitor; the first filter capacitor and the second filter capacitor are connected in series and then connected in parallel with the primary of the second common-mode inductor; the third filter capacitor is connected in parallel with the secondary of the second common-mode inductor; both ends of the first filter capacitor are respectively connected to the positive connection port and the negative connection port of the target battery.

[0031] In one embodiment, the signal attenuation sub-circuit includes a first resistor unit and a second resistor unit; the first resistor unit and the second resistor unit are connected in series and then connected in parallel with the third filter capacitor; both ends of the first resistor unit are connected to the input end of the internal resistance detection device;

[0032] The first resistor unit includes a fixed resistor and a variable resistor connected in parallel.

[0033] In one embodiment, one end of the first filter capacitor connected to the positive connection port of the target battery is in communication with one end of the first resistor unit connected to the positive input port of the internal resistance detection device.

[0034] In a second aspect, the present application further provides an internal resistance detection method. This method is applied to the internal resistance detection device in the first aspect as described above; the internal resistance detection device includes an internal resistance detection device and a signal relay device, the internal resistance detection device is connected to the signal relay device, and the signal relay device is configured to be connected to a target battery to be detected; the method includes:

[0035] Outputting an initial detection signal from the internal resistance detection device to the signal relay device;

[0036] The initial detection signal is amplified by a signal amplification circuit in a signal relay device to obtain a target detection signal, and the target detection signal is output to a target battery;

[0037] An initial measurement signal of the target battery is collected by a signal attenuation circuit in the signal relay device, and the initial measurement signal is subjected to signal attenuation processing to obtain a target measurement signal;

[0038] An internal resistance detection device determines the internal resistance of the target battery according to the initial detection signal and the target measurement signal.

[0039] The above internal resistance detection device and internal resistance detection method. The internal resistance detection device includes an internal resistance detection device and a signal relay device. The internal resistance detection device is connected to the signal relay device, and the signal relay device is used to connect to a target battery to be detected; the internal resistance detection device is used to output an initial detection signal to the signal relay device; the signal relay device includes a signal amplification circuit and a signal attenuation circuit. Among them, the signal amplification circuit is used to amplify the initial detection signal to obtain a target detection signal and output the target detection signal to the target battery; the signal attenuation circuit is used to collect the initial measurement signal of the target battery and perform signal attenuation processing on the initial measurement signal to obtain a target measurement signal; the internal resistance detection device is used to determine the internal resistance of the target battery according to the initial detection signal and the target measurement signal. That is to say, the internal resistance detection device proposed in the embodiment of the present application combines an internal resistance detection device and a signal relay device. The initial detection signal output by the internal resistance detection device is amplified by the signal relay device, and the initial measurement signal of the target battery is subjected to signal attenuation processing, so as to obtain a target measurement signal corresponding to the initial detection signal output by the internal resistance detection device. Furthermore, the internal resistance detection device can calculate the internal resistance of the target battery according to the initial detection signal and the target measurement signal; that is, in this embodiment, when detecting the internal resistance of the target battery, the detection signal applied to the target battery is the target detection signal after amplification processing, and the initial measurement signal of the target battery collected carries the amplified internal resistance measurement signal and the power supply ripple interference signal. Therefore, the signal-to-noise ratio of the measurement signal can be improved, and furthermore, the accuracy of internal resistance detection can be improved.

[0040] In addition, since the internal resistance detection device in the embodiments of the present application can improve the signal-to-noise ratio of the measurement signal, reduce the influence of the power supply ripple interference in the floating charge state on the internal resistance measurement signal, and realize the detection of the battery internal resistance in the floating charge state, that is, it can realize the on-line internal resistance detection of the battery. Moreover, since the internal resistance detection device in the embodiments of the present application can amplify the initial detection signal output by the internal resistance detection device, therefore, it is also applicable to the low-cost internal resistance detection device with a relatively small initial detection signal output; that is, the on-line internal resistance detection of the battery can also be realized by using a low-cost internal resistance detection device and a signal relay device, which can further reduce the cost of the internal resistance detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic structural diagram of the internal resistance detection device provided by the embodiment of the present application;

[0042] Figure 2 is a schematic connection structure diagram of the internal resistance detection device and the battery in one embodiment;

[0043] Figure 3 is a schematic connection structure diagram among the internal resistance detection device, the signal repeater and the battery provided by the embodiment of the present application;

[0044] Figure 4 is a schematic structural diagram of the signal amplification circuit provided by the embodiment of the present application;

[0045] Figure 5 is another schematic structural diagram of the signal amplification circuit provided by the embodiment of the present application;

[0046] Figure 6 is a schematic circuit structure diagram of the signal amplification circuit provided by the embodiment of the present application;

[0047] Figure 7 is a schematic structural diagram of the signal attenuation circuit provided by the embodiment of the present application;

[0048] Figure 8 is a schematic circuit structure diagram of the signal attenuation circuit provided by the embodiment of the present application;

[0049] Figure 9 is a schematic flow chart of the internal resistance detection method in one embodiment.

[0050] DESCRIPTION OF REFERENCE NUMERALS:

[0051] 10: internal resistance detection device; 11: internal resistance detection device; 12: signal relay device;

[0052] 20: target battery; 121: signal amplification circuit; 122: signal attenuation circuit;

[0053] 1211(T1 - Tn): First common - mode inductor; 1212(D1): First bidirectional diode;

[0054] 1213(C1): First isolation capacitor; 1214(R1): First discharge resistor;

[0055] 122a: Signal filtering sub - circuit; 122b: Signal attenuation sub - circuit;

[0056] T0: Second common - mode inductor; C4: First filtering capacitor;

[0057] C3: Second filtering capacitor; C2: Third filtering capacitor;

[0058] R2 + W1: First resistor unit; R3: Second resistor unit. Detailed implementation mode

[0059] In order to make the purpose, technical solutions and advantages of the present application more clear and understandable, the following further details the present application in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0060] The internal resistance detection device provided by the embodiment of the present application is applicable to the field of battery testing technology, especially for testing the performance and quality of storage batteries. The internal resistance detection device can detect the internal resistance of the target battery and further analyze the performance and quality of the target battery according to the internal resistance measurement value, so as to accurately predict the service life of the battery and replace the backward battery in time.

[0061] As a power supply device, batteries are widely used in daily life. For example: for a large number of Class - D computer rooms and base stations, storage batteries are required to provide a stable power supply voltage to ensure the normal operation of network communication equipment. However, since the performance of the battery gradually declines during long - term use, it affects the normal power supply of the equipment and causes adverse effects; therefore, maintenance personnel will regularly inspect and repair the batteries in various equipment. If a backward battery is found, the backward battery needs to be replaced in time to maintain the normal power supply of the equipment.

[0062] In the related art, for a large number of Class D computer rooms and base stations, there is generally no monitoring of the voltage of individual batteries, only the monitoring of the voltage of the entire battery pack. The backward batteries are discovered through the check discharge test. During the test, the voltage of individual batteries needs to be tested one by one at intervals, and the change in its voltage value is observed to determine whether the individual battery is backward. The entire test process takes at least dozens of minutes and at most several hours, with low efficiency. In view of the drawbacks of the check discharge test, an internal resistance detector for battery detection has gradually emerged. By using the internal resistance detector to test the internal resistance and voltage of individual batteries one by one, the check discharge is not required during the test, and the test process of a group of storage batteries can be completed in a few minutes, with higher efficiency. It can quickly discover backward batteries and is more suitable for the inspection and repair of the storage battery packs in a large number of Class D computer rooms and base stations.

[0063] However, when using an internal resistance detector to detect the internal resistance of a battery, the following two main problems are still faced:

[0064] 1. An internal resistance detector capable of online testing of batteries is required

[0065] Generally, an internal resistance detector tests the internal resistance of a battery in a static state. When testing the internal resistance of a battery in a floating charge state, it is extremely vulnerable to the ripple interference of the switching power supply. In severe cases, the test cannot be carried out. Moreover, when there is only one group of storage batteries, the method of disconnecting the battery fuse cannot be used to eliminate the interference of the power supply ripple for testing, otherwise it is extremely easy to cause communication failures due to the momentary fluctuation of the commercial power.

[0066] In addition, when the internal resistance of the battery is small, if the measurement signal is interfered by the power supply ripple, due to the low signal-to-noise ratio of the measurement signal, it is extremely difficult to accurately separate the interference signal from the interfered measurement signal, so as to obtain the true internal resistance measurement signal. In severe interference cases, the measurement cannot even be carried out. In short, traditional internal resistance detectors have the technical problem of poor measurement accuracy when the battery is in a floating charge state.

[0067] 2. A low-cost online internal resistance detector is required

[0068] Although professional internal resistance detectors have high precision, they are expensive and not suitable for large-scale configuration to grass-roots maintenance teams. For grass-roots maintenance personnel, the cost of professional internal resistance detectors is relatively high.

[0069] Based on this, the embodiment of the present application proposes an internal resistance detection device, which combines a low-cost internal resistance detector with a signal repeater. The signal repeater amplifies the detection signal output by the internal resistance detector and attenuates the input measurement signal, so as to improve the signal-to-noise ratio of the internal resistance measurement signal and achieve the purpose of testing the internal resistance of the battery in an online floating charge state. That is, a low-cost and highly anti-interference online internal resistance detector is provided.

[0070] The following uses specific embodiments to elaborate in detail on the technical solution of this application and how the technical solution of this application solves the above technical problems. These several specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be elaborated in some embodiments. The embodiments of this application will be described below in conjunction with the accompanying drawings.

[0071] Figure 1 It is a schematic structural diagram of the internal resistance detection device provided by the embodiment of this application. As Figure 1 shown, the internal resistance detection device 10 includes an internal resistance detection device 11 and a signal relay device 12. The internal resistance detection device 11 is connected to the signal relay device 12, and the signal relay device 12 is used to connect to the target battery 20 to be detected.

[0072] Among them, the internal resistance detection device 11 is used to output an initial detection signal to the signal relay device 12; exemplarily, the internal resistance detection device 11 may include a traditional internal resistance detector for outputting an alternating current detection signal; such as an alternating current signal, that is, the initial detection signal may be an initial alternating current signal.

[0073] Exemplarily, referring to Figure 2 shown, the internal resistance detection device 11 may be a four-wire detection device, that is, it includes two output signal lines (A1+ and A1-) and two input signal lines (B1+ and B1-); when the internal resistance detection device 11 is directly connected to the target battery 20 to be detected, the two output signal lines (A1+ and A1-) can be respectively connected to the positive connection port (+) and the negative connection port (-) of the target battery 20 for applying an alternating current signal to the target battery 20; the two input signal lines (B1+ and B1-) are also respectively connected to the positive connection port (+) and the negative connection port (-) of the target battery 20 for collecting the alternating voltage signal across the target battery 20.

[0074] In the embodiment of this application, referring to Figure 3 shown, in the case where the internal resistance detection device 11 is a four-wire detection device, the signal relay device 12 may include eight signal lines, namely a first input signal line (A1+) and a second input signal line (A1-) connected to the two output signal lines of the internal resistance detection device 11, a first output signal line (A2+) and a second output signal line (A2-) connected to the positive connection port and the negative connection port of the target battery 20, a third input signal line (B2+) and a fourth input signal line (B2-) connected to the positive connection port and the negative connection port of the target battery 20, and a third output signal line (B1+) and a fourth output signal line (B1-) connected to the two input signal lines of the internal resistance detection device 11.

[0075] It should be noted that the first output signal line (A2+) and the third input signal line (B2+), which are connected to the positive electrode connection port of the target battery 20, are respectively connected to different connection ports of the positive electrode of the target battery 20; the second output signal line (A2-) and the fourth input signal line (B2-), which are connected to the negative electrode connection port of the target battery 20, are respectively connected to different connection ports of the negative electrode of the target battery 20.

[0076] Exemplarily, referring to Figure 1 As shown, the signal relay device 12 may include a signal amplification circuit 121 and a signal attenuation circuit 122. Among them, the signal amplification circuit 121 is used to amplify the initial detection signal to obtain a target detection signal and output the target detection signal to the target battery 20; the signal attenuation circuit 122 is used to collect the initial measurement signal of the target battery 20 and perform signal attenuation processing on the initial measurement signal to obtain a target measurement signal; wherein, the initial measurement signal may be the actual measurement signal generated at both ends of the target battery 20 after applying the target detection signal to the target battery 20; and the target measurement signal may be a measurement signal corresponding to the initial detection signal. For example, when the signal attenuation multiple is the same as the signal amplification multiple, the target measurement signal can be understood as the actual measurement signal generated by the target battery 20 after directly applying the initial detection signal to both ends of the target battery 20.

[0077] Furthermore, the signal attenuation circuit 122 may send the target measurement signal to the internal resistance detection device 11, so that the internal resistance detection device 11 can determine the internal resistance of the target battery 20 according to the initial detection signal and the target measurement signal. Exemplarily, when the initial detection signal is an alternating current signal and the target measurement signal is an alternating voltage signal, the internal resistance detection device 11 may calculate the internal resistance of the target battery 20 based on the conversion relationship between current, voltage and resistance according to the alternating voltage signal and the alternating current signal.

[0078] Exemplarily, when the signal relay device 12 includes a signal amplification circuit 121 and a signal attenuation circuit 122, the first input signal line (A1+) and the second input signal line (A1-) of the signal relay device 12 may be used as the two signal input lines of the signal amplification circuit 121, and the first output signal line (A2+) and the second output signal line (A2-) of the signal relay device 12 may be used as the two signal output lines of the signal amplification circuit 121; the third input signal line (B2+) and the fourth input signal line (B2-) of the signal relay device 12 may be used as the two signal input lines of the signal attenuation circuit 122, and the third output signal line (B1+) and the fourth output signal line (B1-) of the signal relay device 12 may be used as the two signal output lines of the signal attenuation circuit 122.

[0079] Optionally, the signal amplification circuit 121 can be designed using components with signal amplification functions such as amplifiers and transformers. Additionally, the signal amplification circuit 121 can adopt an active amplification method or a passive amplification method, etc.; in the embodiments of the present application, the principle and circuit structure of the signal amplification circuit 121 are not specifically limited. Furthermore, for the signal attenuation circuit 122, it can be designed based on the principle of resistor voltage division or using components with signal attenuation functions such as transformers, etc.; in the embodiments of the present application, the principle and circuit structure of the signal attenuation circuit 122 are also not specifically limited.

[0080] It should be noted that the amplification factor of the signal amplification circuit 121 and the attenuation factor of the signal attenuation circuit 122 can be the same or different.

[0081] The internal resistance detection device in this embodiment includes an internal resistance detection device and a signal relay device. The internal resistance detection device is connected to the signal relay device, and the signal relay device is used to connect to the target battery to be detected; the internal resistance detection device is used to output an initial detection signal to the signal relay device; the signal relay device includes a signal amplification circuit and a signal attenuation circuit. Among them, the signal amplification circuit is used to amplify the initial detection signal to obtain a target detection signal and output the target detection signal to the target battery; the signal attenuation circuit is used to collect the initial measurement signal of the target battery and perform signal attenuation processing on the initial measurement signal to obtain a target measurement signal; the internal resistance detection device is used to determine the internal resistance of the target battery according to the initial detection signal and the target measurement signal. That is to say, the internal resistance detection device proposed in the embodiments of the present application combines the internal resistance detection device and the signal relay device. By the signal relay device, the initial detection signal output by the internal resistance detection device is amplified and the initial measurement signal of the target battery is attenuated, so as to obtain a target measurement signal corresponding to the initial detection signal output by the internal resistance detection device. Furthermore, the internal resistance detection device can calculate the internal resistance of the target battery according to the initial detection signal and the target measurement signal. That is, in this embodiment, when detecting the internal resistance of the target battery, the detection signal applied to the target battery is the amplified target detection signal, and the initial measurement signal collected from the target battery carries the amplified internal resistance measurement signal and the power supply ripple interference signal. Therefore, the signal-to-noise ratio of the measurement signal can be improved, and further, the accuracy of internal resistance detection can be improved.

[0082] In addition, since the internal resistance detection device in the embodiment of the present application can improve the signal-to-noise ratio of the measurement signal, reduce the influence of the power supply ripple interference in the floating charge state on the internal resistance measurement signal, and realize the detection of the battery internal resistance in the floating charge state, that is, it can realize the on-line internal resistance detection of the battery. Moreover, since the internal resistance detection device in the embodiment of the present application can amplify the initial detection signal output by the internal resistance detection device, it is also applicable to the low-cost internal resistance detection device with a relatively small output initial detection signal; that is, the on-line internal resistance detection of the battery can also be realized by using a low-cost internal resistance detection device and a signal relay device, which can further reduce the cost of the internal resistance detection device.

[0083] In one embodiment, as Figure 4 shown, the above signal amplification circuit 121 may include a plurality of first common-mode inductors 1211, the primaries of the first common-mode inductors 1211 are connected in series, and the secondaries of the first common-mode inductors 1211 are connected in parallel; the plurality of first common-mode inductors 1211 are used to amplify the initial detection signal to obtain a target detection signal.

[0084] Referring to Figure 4 shown, the primaries of the plurality of first common-mode inductors 1211 are connected in series and then connected to the first input signal line (A1+) and the second input signal line (A1-), and the secondaries of the plurality of first common-mode inductors 1211 are connected in parallel and then connected to the first output signal line (A2+) and the second output signal line (A2-).

[0085] Exemplarily, referring to Figure 6 shown, each first common-mode inductor 1211 may be a 1:1 common-mode inductor. For example, the signal amplification circuit 121 may include n 1:1 common-mode inductors T, that is, T1-Tn. By connecting the primaries in series and the secondaries in parallel, a voltage attenuation of n:1, that is, a current amplification of 1:n, is formed; that is, the signal amplification circuit 121 composed of n 1:1 common-mode inductors can amplify the initial detection signal by n times to obtain the amplified target detection signal; that is, the amplification factor of the target detection signal is equal to the number of the plurality of first common-mode inductors.

[0086] It should be noted that the amplification factor of the signal amplification circuit 121, or rather, the selected number of the first common-mode inductors 1211, can be determined according to the load resistance value range of the AC constant current of the internal resistance detection device 11. The resistance value of the inductor secondary load mapped to the primary should not exceed the maximum load resistance value of the internal resistance detection device 11. Assuming that the AC constant current range of the internal resistance detection device 11 is 10 - 20 Ω, the resistance from the battery terminal including the connection wires, etc. is usually 0.1 - 0.2 Ω. The impedance mapped to the primary is the square of the turns ratio. Selecting too high an amplification factor is likely to cause the internal resistance detection device 11 to exceed the constant current range, resulting in inaccurate testing. Through experimental verification, it is more appropriate to select an amplification factor of about 8 times, and the comprehensive effect is better. That is, 8 1:1 common-mode inductors are used to form a 1:8 current amplification circuit.

[0087] In this embodiment, the signal amplification circuit includes a plurality of first common-mode inductors. The primaries of the first common-mode inductors are connected in series, and the secondaries of the first common-mode inductors are connected in parallel. The plurality of first common-mode inductors are used to amplify the initial detection signal to obtain the target detection signal. That is, in this embodiment, common-mode inductors are used to form a passive signal amplification circuit, which can not only improve the accuracy of signal amplification, but also simplify the circuit and reduce costs.

[0088] In one embodiment, as Figure 5 shown, the signal amplification circuit 121 may further include a first bidirectional diode 1212 (such as D1 in Figure 6 ); the first bidirectional diode 1212 is connected in parallel with the primaries of the plurality of first common-mode inductors 1211 (such as T1 - Tn in Figure 6 ); the first bidirectional diode 1212 is used to suppress the instantaneous voltage of the target battery 20.

[0089] Exemplarily, the first bidirectional diode 1212 may be a bidirectional surge suppression diode, which is used to suppress the reverse amplified voltage signal generated instantaneously when connecting the target battery, so as to prevent the output end of the internal resistance detection device 11 from being broken down by high voltage and ensure that the internal resistance detection device 11 can work stably and reliably.

[0090] In one embodiment, as Figure 5 shown, the signal amplification circuit 121 may further include a first isolation capacitor 1213 (such as C1 in Figure 6 ) and a first discharge resistor 1214 (such as Figure 6R1) in; after the first isolation capacitor 1213 and the first discharge resistor 1214 are connected in series, they are connected in parallel with the secondary windings of multiple first common-mode inductors 1211; both ends of the first discharge resistor 1214 are respectively connected to the positive connection port and the negative connection port of the target battery 20, that is, both ends of the first discharge resistor 1214 serve as the first output signal line (A2+) and the second output signal line (A2-) of the signal amplification resistor 121.

[0091] Among them, the first isolation capacitor 1213 is used to isolate the DC voltage of the target battery 20; the first discharge resistor 1214 is used to discharge or release the charge on the first isolation capacitor 1213 after the detection is completed.

[0092] Exemplarily, the first isolation capacitor 1213 can be a non-polar capacitor, whose function is to isolate the DC voltage of the target battery 20 and inject the amplified target detection signal (such as the amplified AC current signal) into the target battery 20; optionally, the first isolation capacitor 1213 can be a non-polar capacitor with a voltage above 63V, such as a 680uF non-polar capacitor.

[0093] In one embodiment, as Figure 6 shown, the negative extreme ends of the primary windings of the multiple first common-mode inductors and the negative extreme ends of the secondary windings of the multiple first common-mode inductors are connected, that is, the second input signal line (A1-) and the second output signal line (A2-) of the signal amplification circuit 121 are connected; exemplarily, the second input signal line (A1-) and the second output signal line (A2-) of the signal amplification circuit 121 can be directly connected, or the second input signal line (A1-) and the second output signal line (A2-) can be commonly connected to the ground GND, as Figure 6 shown, both of which are grounded; thus, the effect of connecting the second input signal line (A1-) and the second output signal line (A2-) is achieved.

[0094] Since the second output signal line (A2-) of the signal amplification circuit 121 is connected to the negative pole of the target battery, therefore, after the second input signal line (A1-) and the second output signal line (A2-) of the signal amplification circuit 121 are connected, it can be used as the negative input terminal for collecting the DC voltage of the target battery, thereby forming a negative path for the DC voltage; then, combined with the signal input terminal connected to the positive connection port of the target battery, the on-line detection and measurement of the DC voltage of the target battery can be realized.

[0095] Exemplarily, referring to the above Figure 3As shown, the third input signal line (B2+) of the signal relay device 12 can be connected to the third output signal line (B1+). Since the third input signal line (B2+) of the signal relay device 12 is connected to the positive connection port of the target battery, it can be used as the positive input terminal for collecting the DC voltage of the target battery. Thus, the DC voltage across the target battery 20 can be collected through the third input signal line (B2+) and the second output signal line (A2-) of the signal relay device 12. And the collected DC voltage signal is output to the internal resistance detection device 11 through the third output signal line (B1+) and the second input signal line (A1-) of the signal relay device 12, so that the internal resistance detection device 11 can obtain the DC voltage value of the target battery 20.

[0096] In one embodiment, for the signal amplification circuit 121, it can be implemented not only by using a common-mode inductor, that is, the circuit structure of the signal amplification circuit 121 shown above Figure 4 but also by using a transformer. That is, the signal amplification circuit 121 can include a transformer, and through the transformer, the initial detection signal is amplified to obtain the target detection signal. That is to say, based on Figure 4 the circuit structure of the signal amplification circuit 121 shown, Figure 4 the multiple first common-mode inductors in

[0097] can be replaced by a transformer. That is, the function of one transformer is equivalent to the function of multiple first common-mode inductors, so as to obtain the signal amplification circuit 121 implemented based on the transformer.

[0098] Exemplarily, referring to the above Figure 5As shown, in the case where the signal amplification circuit 121 includes a transformer, the signal amplification circuit may also include a second bidirectional diode; the second bidirectional diode is connected in parallel with the primary of the transformer; and the second bidirectional diode is used to suppress the instantaneous voltage of the target battery. In addition, the signal amplification circuit 121 may also include a second isolation capacitor and a second discharge resistor; after the second isolation capacitor and the second discharge resistor are connected in series, they are connected in parallel with the secondary of the transformer; the two ends of the second discharge resistor are respectively connected to the positive connection port and the negative connection port of the target battery; wherein the second isolation capacitor is used to isolate the DC voltage of the target battery; the second discharge resistor is used to discharge the charge on the second isolation capacitor after the detection is completed.

[0099] For example, referring to the above Figure 6 As shown, when the signal amplifying circuit 121 includes a transformer, the primary negative terminal of the transformer and the secondary negative terminal of the transformer are connected. Thus, the second input signal line (A1-) and the second output signal line (A2-) of the signal amplifying circuit 121 are connected, and a negative electrode path for the DC voltage of the target battery is formed through the two connected negative terminals of the transformer; finally, the online detection and measurement of the DC voltage of the target battery is realized.

[0100] That is to say, the above Figure 4 , Figure 5 and Figure 6 The first common mode inductors are replaced with transformers as a whole, thereby obtaining a signal amplification circuit based on a transformer. The implementation method can refer to the above Figure 4 , Figure 5 and Figure 6 The description of the relevant contents in the corresponding embodiments will not be repeated here.

[0101] In one embodiment, Figure 7As shown, the above signal attenuation circuit 122 includes a signal filtering sub-circuit 122a and a signal attenuation sub-circuit 122b; wherein, the signal filtering sub-circuit 122a is connected to the positive connection port and the negative connection port of the target battery 20 through a third input signal line (B2+) and a fourth input signal line (B2-), and is used to collect the initial measurement signal of the target battery 20 and perform signal filtering processing on the initial measurement signal to obtain an intermediate measurement signal; the output end of the signal filtering sub-circuit 122a is connected to the input end of the signal attenuation sub-circuit 122b for transmitting the intermediate measurement signal to the signal attenuation sub-circuit 122b; the signal attenuation sub-circuit 122b is used to perform signal attenuation processing on the intermediate measurement signal to obtain a target measurement signal, and is connected to the internal resistance detection device 11 through a third output signal line (B1+) and a fourth output signal line (B1-) to send the target measurement signal to the internal resistance detection device 11, so that the internal resistance detection device 11 determines the internal resistance of the target battery according to the initial detection signal and the target measurement signal.

[0102] Optionally, the signal filtering sub-circuit 122a can adopt a conventional signal filtering circuit structure for filtering the interference signals in the initial measurement signal, and the interference signals include power supply ripple interference signals.

[0103] Exemplarily, referring to Figure 8 As shown, the signal filtering sub-circuit 122a can include a second common-mode inductor T0 and a filtering capacitor C; the filtering capacitor C can include a first filtering capacitor C4, a second filtering capacitor C3, and a third filtering capacitor C2; the first filtering capacitor C4 and the second filtering capacitor C3 are connected in series and then connected in parallel with the primary of the second common-mode inductor T0; the third filtering capacitor C2 is connected in parallel with the secondary of the second common-mode inductor T0; both ends of the first filtering capacitor C4 are respectively connected to the positive connection port and the negative connection port of the target battery 20, that is, both ends of the first filtering capacitor C4 can respectively serve as two signal input lines of the signal attenuation circuit 122, that is, they can serve as the third input signal line (B2+) and the fourth input signal line (B2-) of the signal relay device 12.

[0104] Exemplarily, referring to Figure 8 As shown, the signal attenuation sub-circuit 122b can include a first resistor unit (such as Figure 8 R2 and W1 in Figure 7 ) and a second resistor unit (such as Figure 8 R3 in Figure 8In W1), by adjusting the resistance value of the variable resistor W1, the attenuation multiple of the signal attenuation sub-circuit 122b can be adjusted, realizing precise and flexible control of the attenuation multiple; for example: during the long-term use of the internal resistance detection device, the resistance value of the variable resistor W1 can be adaptively adjusted according to the internal resistance detection result of the internal resistance detection device to ensure the detection accuracy of the internal resistance detection device.

[0105] Based on Figure 8 For the circuit structure of the signal attenuation circuit 122 shown, the initial measurement signal (such as an AC voltage signal) across the target battery 20 can first be filtered by the first filter capacitor C4, then coupled by the second filter capacitor C3 and the second common-mode inductor T0, and then filtered again by the third filter capacitor C2; afterwards, it is attenuated by about n times by the attenuator composed of the first resistor unit R2, W1, and the second resistor unit R3 to obtain the target measurement signal; finally, it is connected to the signal receiving end of the internal resistance detection device 11 through the third output signal line (B1+) and the fourth output signal line (B1-), and the target measurement signal is transmitted to the internal resistance detection device 11. Benefiting from the frequency characteristics of the manganese-zinc magnetic core material, the second common-mode inductor T0 in the signal attenuation line 122 can effectively suppress the 50 - 100 Hz power supply ripple interference signal carried in the initial measurement signal.

[0106] In one embodiment, referring to Figure 8 shown, one end of the first filter capacitor connected to the positive connection port of the target battery can be connected to one end of the first resistor unit connected to the positive input port of the internal resistance detection device, achieving the effect of connecting the third input signal line (B2+) and the third output signal line (B1+) of the signal attenuation circuit 122 to each other, thereby serving as the positive path for collecting the DC voltage of the target battery 20; combined with the second input signal line (A1-) and the second output signal line (A2-) connected to each other in the signal amplification circuit 121, the DC voltage of the target battery 20 can be collected to achieve real-time detection of the DC voltage.

[0107] In one embodiment, a passive signal repeater is provided, and the passive signal repeater can include the signal amplification circuit as shown above Figure 6 and the signal attenuation circuit as shown above Figure 8 shown; the passive signal repeater can be combined with a low-cost internal resistance detection device to form an internal resistance detection device. Among them, the internal resistance detection device can be used to output an initial detection signal to the passive signal repeater, receive the target measurement signal returned by the passive signal repeater, calculate the internal resistance of the target battery, and output and display it. The internal resistance detection device can use the currently relatively mature lithium battery internal resistance meter or a customized lithium battery internal resistance meter with better performance.

[0108] The passive signal repeater amplifies the initial detection signal output by the internal resistance detection device in a passive manner and attenuates the input initial measurement signal. Using the structures shown in Figure 6 and Figure 8 in combination with the internal resistance detection device, they jointly form an online internal resistance meter for true four-wire measurement, which can simultaneously measure the internal resistance and voltage value of the storage battery, and can also be used to measure the contact resistance. The measurement results are displayed on the same screen.

[0109] Compared with the "traditional lithium battery internal resistance meter", the online internal resistance meter provided in this embodiment has two advantages. One is that it has a stronger test signal current. When the amplification factor is 8 times, a test current of about 800 mA can be achieved, which is much higher than the commonly used 50 mA, enabling it to have stronger anti-interference ability and be able to measure the internal resistance of the battery online. The other is that it is designed for large-capacity storage batteries in the computer room, with only one fixed range of 20.00 mΩ / 99.999 v, which simplifies the circuit design, reduces the cost, and still fully meets the test requirements.

[0110] Generally speaking, the online internal resistance detection device provided in the embodiment of this application makes full use of the existing internal resistance meter technology, develops a passive signal repeater through basic principles, amplifies the detection signal output by the internal resistance meter and attenuates the input measurement signal without changing the performance of the internal resistance meter, and can jointly form a new online internal resistance meter, enabling the internal resistance meter to measure the internal resistance of the battery online in an environment where it could not be measured online before.

[0111] In terms of details, the method of using a transformer to passively amplify the detection signal has a simpler and more reliable circuit structure compared to the generally used active amplification method; a transformer proposed in the embodiment of this application that is more suitable for 1000 Hz detection signals creatively uses n 1:1 common mode inductors, which are combined into a signal transformer with n-fold current amplification by connecting the primary in series and the secondary in parallel. Benefiting from the frequency characteristics of the manganese-zinc magnetic core material, it is not only suitable for the propagation of 1000 Hz detection signals, but also can effectively suppress the power supply ripple of 50 - 100 Hz when used for reception. It is a flexible use of common mode inductors for high-frequency filtering occasions, and its performance is better than that of commonly used signal transformers.

[0112] The following is a comparative analysis of the traditional internal resistance meter and the internal resistance detection device of the present application through experiments. Among them, the internal resistance detection device 1 of the present application is composed of a traditional and relatively low-cost internal resistance meter A (about 50 mA) and a passive signal repeater, and the internal resistance detection device 2 of the present application is composed of a customized and relatively low-cost internal resistance meter B (about 100 mA) and a passive signal repeater. The signal amplification circuit in the passive signal repeater uses 8 common-mode inductors, and a repeater with an amplification factor of 8 is designed in a passive working mode to meet the need for the detection signal to increase by 16 times to reach about 800 mA, thereby achieving a stronger anti-interference ability.

[0113] First, the current value of the initial detection signal of the traditional and relatively low-cost internal resistance meter A is measured to be 55 mA, the set value of the current value of the initial detection signal of the customized and relatively low-cost internal resistance meter B (about 100 mA) is 100 mA, and the measured value is about 98 mA. The measured value of the current value of the initial detection signal of the internal resistance detection device 2 is about 822 mA.

[0114] Next, the internal resistance of the target battery in the floating charge state is detected by the traditional and relatively low-cost internal resistance meter A, the traditional and relatively high-cost internal resistance meter C, the internal resistance detection device 1 of the present application, and the internal resistance detection device 2 of the present application respectively, and the following data are obtained:

[0115] When the traditional and relatively high-cost internal resistance meter C is used to detect the resistance of the target battery, the detection results fluctuate between 0.326 - 0.429 mΩ, and the numerical fluctuations are relatively large.

[0116] When the traditional and relatively low-cost internal resistance meter A is used to detect the resistance of the target battery, the detection results fluctuate between 0.29 - 0.47 mΩ, and the numerical fluctuations are very large.

[0117] When the internal resistance detection device 1 of the present application is used to detect the resistance of the target battery, the detection results fluctuate between 0.35 - 0.39 mΩ, and the numerical fluctuations are greatly reduced.

[0118] When the internal resistance detection device 2 of the present application is used to detect the resistance of the target battery, the detection results fluctuate between 0.36 - 0.37 mΩ. The numerical fluctuations are the smallest and the anti-interference performance is the best.

[0119] Through the above comparative analysis, it can be seen that the internal resistance detection device composed of the internal resistance meter and the signal repeater proposed in the present application has normal internal resistance testing function, accurate test results, and strong anti-interference ability; especially the internal resistance detection device composed of the customized internal resistance meter (i.e., after increasing the AC current range of the detection signal) and the signal repeater has stronger anti-interference ability, more accurate detection results, and compared with the traditional and relatively high-cost internal resistance meter, the detection performance has also been greatly improved and the detection accuracy is higher.

[0120] In addition, it should be noted that when the batteries in the computer room are usually tested online (i.e., in the floating charge state), the internal resistance of the battery under test is actually measured. It is the total internal resistance value in parallel after being connected in series with other connected batteries (including the internal resistance of the connecting wires) and the power supply internal resistance; it is slightly smaller than the actual internal resistance value measured in the static state. According to theoretical calculations, when the internal resistance of the batteries is normal, the error between the internal resistance value in the floating charge state and the internal resistance value in the static state does not exceed 3%. Therefore, the error brought by the online test will not affect the judgment of the backward batteries.

[0121] Through actual scenario tests, in a computer room with a relatively small switching power supply ripple and two groups of batteries, by using the internal resistance detection device of the present application, the internal resistance values of the batteries are compared and tested when the power supply connection is disconnected (i.e., in the static state) and when the power supply is connected (i.e., in the floating charge state). The experimental verification shows that the measured internal resistance value in the floating charge state is very close to the measured internal resistance value in the static state, and the difference is less than 3%.

[0122] In one embodiment, as Figure 9 shown, there is also provided an internal resistance detection method, which is applied to the internal resistance detection device in any of the above embodiments; the internal resistance detection device includes an internal resistance detection device and a signal relay device, the internal resistance detection device is connected to the signal relay device, and the signal relay device is used to connect to the target battery to be detected; the method includes:

[0123] Step 901, output an initial detection signal from the internal resistance detection device to the signal relay device.

[0124] Step 902, amplify the initial detection signal through the signal amplification circuit in the signal relay device to obtain a target detection signal, and output the target detection signal to the target battery.

[0125] Step 903, collect the initial measurement signal of the target battery through the signal attenuation circuit in the signal relay device, and perform signal attenuation processing on the initial measurement signal to obtain a target measurement signal.

[0126] Step 904, determine the internal resistance of the target battery according to the initial detection signal and the target measurement signal by the internal resistance detection device.

[0127] In the internal resistance detection method proposed in this embodiment, by combining an internal resistance detection device and a signal relay device, the signal relay device can amplify the initial detection signal output by the internal resistance detection device and attenuate the initial measurement signal of the target battery, so as to obtain a target measurement signal corresponding to the initial detection signal output by the internal resistance detection device. Furthermore, the internal resistance detection device can calculate the internal resistance of the target battery according to the initial detection signal and the target measurement signal. That is, in this embodiment, when detecting the internal resistance of the target battery, the detection signal applied to the target battery is the amplified target detection signal, and the initial measurement signal of the target battery collected carries the amplified internal resistance measurement signal and the power supply ripple interference signal. Therefore, the signal-to-noise ratio of the measurement signal can be improved, and furthermore, the accuracy of the internal resistance detection can be improved.

[0128] In addition, since the internal resistance detection method in the embodiment of the present application can improve the signal-to-noise ratio of the measurement signal, reduce the influence of the power supply ripple interference on the internal resistance measurement signal in the floating charge state, and realize the detection of the battery internal resistance in the floating charge state, that is, it can realize the on-line internal resistance detection of the battery. Moreover, since the internal resistance detection method in the embodiment of the present application can amplify the initial detection signal output by the internal resistance detection device, it is also applicable to the low-cost internal resistance detection device with a small initial detection signal output. That is, the on-line internal resistance detection of the battery can be realized by using a low-cost internal resistance detection device and a signal relay device, which can further reduce the cost of the internal resistance detection.

[0129] It should be understood that although the steps in the flowcharts involved in the above-described embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limitation, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-described embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least a part of other steps or steps in other steps.

[0130] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combinations of these technical features do not conflict, they should be considered as the scope described in this specification.

[0131] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. An internal resistance detection device, characterized in that, The internal resistance detection device includes an internal resistance detection device and a signal relay device. The internal resistance detection device is connected to the signal relay device, and the signal relay device is used to connect to a target battery to be detected; The internal resistance detection device is used to output an initial detection signal to the signal relay device; The signal relay device includes a signal amplification circuit and a signal attenuation circuit. Among them, the signal amplification circuit is used to amplify the initial detection signal to obtain a target detection signal and output the target detection signal to the target battery; the signal attenuation circuit is used to collect an initial measurement signal of the target battery and perform signal attenuation processing on the initial measurement signal to obtain a target measurement signal; The internal resistance detection device is used to determine the internal resistance of the target battery according to the initial detection signal and the target measurement signal.

2. The internal resistance detection device according to claim 1, characterized in that The signal amplification circuit includes a plurality of first common-mode inductors. The primaries of the first common-mode inductors are connected in series, and the secondaries of the first common-mode inductors are connected in parallel; The plurality of first common-mode inductors are used to amplify the initial detection signal to obtain the target detection signal.

3. The internal resistance detection device according to claim 2, wherein, The first common-mode inductor is a 1:1 common-mode inductor; the amplification factor of the target detection signal is equal to the number of the plurality of first common-mode inductors.

4. The internal resistance detection device according to claim 2, characterized in that, The signal amplification circuit further includes a first bidirectional diode; the first bidirectional diode is connected in parallel with the primaries of the plurality of first common-mode inductors; The first bidirectional diode is used to suppress the instantaneous voltage of the target battery.

5. The internal resistance detection device according to claim 2, wherein, The signal amplification circuit further includes a first isolation capacitor and a first discharge resistor; after the first isolation capacitor and the first discharge resistor are connected in series, they are connected in parallel with the secondaries of the plurality of first common-mode inductors; both ends of the first discharge resistor are respectively connected to the positive connection port and the negative connection port of the target battery; The first isolation capacitor is used to isolate the DC voltage of the target battery; The first discharge resistor is used to discharge the charge on the first isolation capacitor after the detection is completed.

6. The internal resistance detection device according to claim 2, characterized in that, The negative terminals of the primaries of the plurality of first common-mode inductors and the negative terminals of the secondaries of the plurality of first common-mode inductors are connected.

7. The internal resistance detection device according to claim 1, wherein, The signal amplification circuit includes a transformer; The transformer is used to amplify the initial detection signal to obtain the target detection signal.

8. The internal resistance detection device according to claim 7, characterized in that, The signal amplification circuit further includes a second bidirectional diode; the second bidirectional diode is connected in parallel with the primary of the transformer; The second bidirectional diode is used to suppress the instantaneous voltage of the target battery.

9. The internal resistance detection device according to claim 7, wherein, The signal amplification circuit further includes a second isolation capacitor and a second discharge resistor; after the second isolation capacitor and the second discharge resistor are connected in series, they are connected in parallel with the secondary of the transformer; both ends of the second discharge resistor are respectively connected to the positive connection port and the negative connection port of the target battery; The second isolation capacitor is used to isolate the DC voltage of the target battery; The second discharge resistor is used to discharge the charge on the second isolation capacitor after the detection is completed.

10. The internal resistance detection device according to claim 7, characterized in that, The negative terminal of the primary of the transformer and the negative terminal of the secondary of the transformer are connected.

11. The internal resistance detection device according to any one of claims 1 to 10, characterized in that, The signal attenuation circuit includes a signal filtering sub-circuit and a signal attenuation sub-circuit; The signal filtering sub-circuit is configured to collect an initial measurement signal of the target battery and perform signal filtering processing on the initial measurement signal to obtain an intermediate measurement signal; The signal attenuation sub-circuit is configured to perform signal attenuation processing on the intermediate measurement signal to obtain the target measurement signal.

12. The internal resistance detection device according to claim 11, characterized in that The signal filtering sub-circuit includes a second common-mode inductor and filtering capacitors; the filtering capacitors include a first filtering capacitor, a second filtering capacitor, and a third filtering capacitor; the first filtering capacitor and the second filtering capacitor are connected in series and then connected in parallel with the primary of the second common-mode inductor; the third filtering capacitor is connected in parallel with the secondary of the second common-mode inductor; two ends of the first filtering capacitor are respectively connected to the positive connection port and the negative connection port of the target battery.

13. The internal resistance detection device according to claim 12, characterized in that, The signal attenuation sub-circuit includes a first resistor unit and a second resistor unit; the first resistor unit and the second resistor unit are connected in series and then connected in parallel with the third filtering capacitor; two ends of the first resistor unit are connected to the input end of the internal resistance detection device; The first resistor unit includes a fixed resistor and a variable resistor connected in parallel.

14. The internal resistance detection device according to claim 13, characterized in that One end of the first filtering capacitor connected to the positive connection port of the target battery is connected to one end of the first resistor unit connected to the positive input port of the internal resistance detection device.

15. A method for detecting internal resistance, characterized in that, Applied to the internal resistance detection device according to any one of claims 1 to 14; the internal resistance detection device includes an internal resistance detection device and a signal relay device, the internal resistance detection device is connected to the signal relay device, and the signal relay device is used to connect to a target battery to be detected; the method includes: Outputting an initial detection signal from the internal resistance detection device to the signal relay device; Amplifying the initial detection signal through a signal amplification circuit in the signal relay device to obtain a target detection signal, and outputting the target detection signal to the target battery; Collecting an initial measurement signal of the target battery through the signal attenuation circuit in the signal relay device and performing signal attenuation processing on the initial measurement signal to obtain a target measurement signal; Determining the internal resistance of the target battery by the internal resistance detection device according to the initial detection signal and the target measurement signal.

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