WO2023207404A1

WO2023207404A1 - Method for measuring internal resistance of battery, and circuit for measuring internal resistance of battery

Info

Publication number: WO2023207404A1
Application number: PCT/CN2023/081887
Authority: WO
Inventors: 王维林
Original assignee: 深圳市道通科技股份有限公司
Priority date: 2022-04-26
Filing date: 2023-03-16
Publication date: 2023-11-02
Also published as: CN114910808A

Abstract

A method for measuring an internal resistance of a battery, and a circuit for measuring an internal resistance of a battery, which relate to the technical field of batteries. The method comprises: determining the capacity range of a battery to be subjected to measurement (S1); according to the capacity range of said battery, determining measurement logic of said battery (S2); according to the measurement logic, acquiring a voltage and a current of said battery (S3); and according to the measurement logic, the voltage and the current, calculating an internal resistance of said battery (S4). That is, targeted internal resistance measurement is performed on a battery to be subjected to measurement, such that the accuracy of measurement for an internal resistance of said battery can be improved.

Description

A battery internal resistance detection method and battery internal resistance detection circuit

This application requests the priority of the Chinese patent application submitted to the China Patent Office on April 26, 2022, with the application number 202210450918.0 and the application name "A battery internal resistance detection method and battery internal resistance detection circuit", and its entire content is approved This reference is incorporated into this application.

Technical field

The present application relates to the field of battery technology, and in particular to a battery internal resistance detection method and a battery internal resistance detection circuit.

Background technique

The measurement accuracy of battery internal resistance is very important to the judgment of battery performance. Usually, the detection of battery internal resistance is at the milliohm level, which requires very high detection accuracy. At present, the DCIR (Direct Current Internal Resistance) test method is generally used to test the internal resistance of batteries with larger capacities. The ACIR (Alternating Current Internal Resistance) method is usually used to measure the internal resistance of batteries with small capacity. However, the ACIR test method has very high requirements for interference, filtering and other processing, and the ACIR test line is easily affected by the outside world. interference, the accuracy is not as high as the DCIR test method. Using a single measurement method and calculation technology to measure the internal resistance of most batteries on the market makes the repeatable results of battery internal resistance unsatisfactory, and the test accuracy is also greatly affected by the detection environment.

Contents of the invention

The main technical problem solved by the embodiments of this application is to provide a battery internal resistance detection method and a battery internal resistance detection circuit, which can improve the accuracy of battery internal resistance detection.

In order to solve the above technical problems, one technical solution adopted in the embodiment of the present application is to provide a battery internal resistance detection method, which includes: determining the capacity range of the battery to be tested; determining the capacity range of the battery to be tested according to the capacity range of the battery to be tested Detection logic of the battery; obtain the voltage and current of the battery to be tested according to the detection logic; and output the internal resistance of the battery to be tested based on the detection logic, the voltage and the current.

In some embodiments, the detection logic includes first logic and second logic, the capacity range includes a first capacity range and a second capacity range, and the battery to be tested is determined based on the capacity range of the battery to be tested. The detection logic of the battery includes: when the capacity range of the battery to be tested is within the first capacity range, determining to use the first logic to detect the internal resistance of the battery to be tested; when the capacity range of the battery to be tested is In the second capacity range, it is determined to use the second logic to detect the internal resistance of the battery to be tested.

In some embodiments, the first logic includes a first charging logic and a first discharging logic, the second logic includes a second charging logic and a second discharging logic, and the voltage of the battery under test includes a first charging voltage. , the second charging voltage, the first discharging voltage and the second discharging voltage. The current of the battery to be tested includes the first charging current, the second charging current, the first discharging current and the second discharging current. According to the detection Logically obtaining the voltage and current of the battery under test includes: when the capacity range of the battery under test is within the first capacity range, obtaining the first charging voltage of the battery under test according to the first charging logic and the first charging current, and obtain the first discharge voltage and the first discharge current of the battery under test according to the first discharge logic; when the capacity range of the battery under test is within the second capacity range, according to The second charging logic obtains a second charging voltage and a second charging current of the battery under test, and obtains a second discharge voltage and a second discharge current of the battery under test according to the second discharging logic.

In some embodiments, the internal resistance of the battery to be tested includes a charging internal resistance and a discharging internal resistance. According to the detection logic, the voltage and the current, outputting the internal resistance of the battery to be tested includes: When the capacity range of the battery to be tested is within the first capacity range, the charging internal resistance of the battery to be tested is calculated according to the first charging logic, the first charging voltage and the first charging current, Calculate the discharge internal resistance of the battery under test according to the first discharge logic, the first discharge voltage and the first discharge current; when the capacity range of the battery under test is within the second capacity range, The charging internal resistance of the battery under test is calculated according to the second charging logic, the second charging voltage and the second charging current, and the charging internal resistance of the battery to be tested is calculated according to the second discharging logic, the second discharging voltage and the second charging current. Second, the discharge current is used to calculate the discharge internal resistance of the battery to be tested.

In order to solve the above technical problems, another technical solution adopted in the embodiment of the present application is to provide a battery internal resistance detection circuit, including a power module, a detection module, a control module, and a sampling module. The power module is connected to the detection module respectively. , the control module, the sampling module and the battery to be tested are connected, the control module is connected with the detection module and the sampling module respectively, the detection module and The sampling module is connected to the battery to be tested respectively, and the power module is used to provide power for the detection module, the control module, the sampling module and the battery to be tested; the detection module is used to provide power according to The instruction of the control module is to detect the internal resistance of the battery to be tested in the first capacity range or the internal resistance of the battery to be tested in the second capacity range; the sampling module is used to collect the voltage and current of the battery to be tested. ; The control module is used to perform the battery internal resistance detection method as described above.

In some embodiments, the detection module includes a first detection unit and a second detection unit. The first detection unit is respectively connected to the power module and the battery to be tested. The second detection unit is respectively connected to the battery. The power module is connected to the battery to be tested, the first detection unit is used to detect the battery to be tested in the first capacity range; the second detection unit is used to detect the battery to be tested in the second capacity range. .

In some embodiments, the first detection unit includes a switch 1, a switch 2, a switch Q1, a switch Q2, and a resistor stack a. The second end of the switch 1 is connected to the first end of the switch Q1. The second end of the switch Q1 is connected to the power module, the first end of the switch 1 is connected to the first end of the switch 2 and the first end of the battery to be tested respectively, and the second end of the switch 2 The terminal is connected to the first terminal of the switch Q2, the second terminal of the switch Q2 is connected to the first terminal of the resistor stack a, and the second terminal of the resistor stack a is respectively connected to the power module and the Connect the second terminal of the battery under test.

In some embodiments, the second detection unit includes switch 3, switch 4, switch 5, switch Q3, switch Q4, switch Q5, resistor stack b, resistor stack c, and the first end of the switch 3 is connected to the The first end of the switch Q3 is connected to the power module, and the second end of the switch 3 is connected to the first end of the switch 4 and the first end of the switch 5 respectively. and the battery to be tested, the second end of the switch 4 is connected to the first end of the switch Q4, the second end of the switch Q4 is connected to the first end of the resistor stack b, the switch The second end of 5 is connected to the first end of the switch Q5, the second end of the switch Q5 is connected to the first end of the resistor stack c, and the second end of the battery to be tested is connected to the power supply respectively. The module, the second end of the resistor stack b and the second end of the resistor stack c are connected.

In some embodiments, the sampling module includes a sensor unit, an operational amplifier unit, a data sampling unit and a signal processing unit. The sensor unit is connected to the battery to be tested and the operational amplifier unit respectively. The operational amplifier unit Connected to the data sampling unit, the data sampling unit is connected to the signal processing unit, the signal processing unit is connected to the control module, and the sensor unit is used to collect the current signal and voltage of the battery to be tested. signal; the operational amplifier unit is used to de-interference the collected current signal and the voltage signal; the data acquisition unit is used to sample the de-interferenced current signal and the de-interferenced voltage signal. , obtain the sampled current signal and the sampled voltage signal; the signal processing unit is used to perform signal processing on the sampled current signal and the sampled voltage signal, and obtain the current and voltage of the battery to be tested.

In some embodiments, the sensor unit includes a current sensor and a voltage sensor, the current sensor is connected in series with the battery under test, and the voltage sensor is connected in parallel with the battery under test.

In order to solve the above technical problems, another technical solution adopted in the embodiment of the present application is to provide a battery internal resistance detection device, including: at least one processor; and a memory communicatively connected with the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor, so that the at least one processor can execute the battery internal resistance detection method.

In order to solve the above technical problems, another technical solution adopted by the embodiments of the present application is to provide a computer-readable storage medium that stores computer-executable instructions, and the computer-executable instructions are used to use The computer executes the battery internal resistance detection method.

Beneficial effects of the embodiments of the present application: Different from the situation in the prior art, the battery internal resistance detection method and battery internal resistance detection circuit provided by the embodiments of the present application determine the capacity range of the battery to be tested, and according to the battery to be tested. The capacity range determines the detection logic of the battery to be tested, the voltage and current of the battery to be tested are obtained according to the detection logic, and the internal content of the battery to be tested is output based on the detection logic, the voltage and the current. block. That is, by performing targeted internal resistance detection on the battery to be tested, the accuracy of battery internal resistance detection can be improved.

Description of the drawings

One or more embodiments are illustrated through the corresponding drawings. These exemplary illustrations do not constitute limitations to the embodiments. Elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified. Disclaimer: The figures in the accompanying drawings are not to scale. limit.

Figure 1 is a schematic structural diagram of a battery internal resistance detection system provided by an embodiment of the present application;

Figure 2 is a schematic flow chart of a battery internal resistance detection method provided by an embodiment of the present application;

Figure 3 is a schematic flowchart of determining the detection logic of the battery to be tested provided by an embodiment of the present application;

Figure 4 is a schematic flowchart of obtaining the voltage and current of the battery to be tested provided by an embodiment of the present application;

Figure 5 is a schematic flowchart of outputting the internal resistance of the battery to be tested provided by an embodiment of the present application;

Figure 6 is a schematic structural diagram of a battery internal resistance detection circuit provided by an embodiment of the present application;

Figure 7 is a schematic circuit structure diagram of a battery internal resistance detection circuit provided by an embodiment of the present application;

Figure 8 is a schematic circuit structure diagram of the first detection unit provided by the embodiment of the present application;

Figure 9 is a schematic circuit structure diagram of the second detection unit provided by the embodiment of the present application;

Figure 10 is a schematic diagram of voltage changes when switch Q1 is turned on.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

It should be noted that, if there is no conflict, various features in the embodiments of the present application can be combined with each other, and both are within the protection scope of the present application. In addition, although the functional modules are divided in the device schematic diagram and the logical sequence is shown in the flow chart, in some cases, the module division in the device schematic diagram or the order in the flow chart can be performed. The steps shown or described.

Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by a person skilled in the technical field belonging to this application. The terms used in the description of this application are only for the purpose of describing specific embodiments and are not used to limit this application. As used in this specification, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Please refer to FIG. 1 , which is a schematic structural diagram of a battery internal resistance detection system 300 provided by an embodiment of the present application. As shown in FIG. 1 , the battery internal resistance detection system 300 includes a battery 200 to be tested and a battery internal resistance detection circuit 100 .

The battery internal resistance detection circuit 100 is electrically connected to the battery to be tested 200 . The battery internal resistance detection circuit 100 is used to measure the internal resistance of the battery to be tested 200. The internal resistance of the battery to be tested 200 includes a charging internal resistance and a discharging internal resistance. The battery 200 to be tested may be a lead-acid battery or a lithium battery.

Specifically, the battery internal resistance detection circuit 100 determines the capacity range of the battery 200 to be tested, determines the detection logic of the battery 200 to be tested according to the capacity range of the battery 200 to be tested, and obtains the detection logic according to the detection logic. Based on the voltage and current of the battery 200 under test, the internal resistance of the battery 200 under test is calculated based on the detection logic, the voltage and the current. The battery to be tested 200 includes a battery to be tested 200 in a first capacity range and a battery to be tested 200 in a second capacity range. In the embodiment of the present application, two different internal resistance detection methods are used for the battery 200 to be tested in the first capacity range and the battery 200 to be tested in the second capacity range, in order to obtain a more accurate measurement of the battery to be tested. The internal resistance of the battery 200.

Please refer to Figure 2. Figure 2 is a schematic flow chart of a battery internal resistance detection method provided by an embodiment of the present application. The embodiment of the present application provides a battery internal resistance detection method applied to the above-mentioned battery internal resistance detection circuit 100. This method can be executed by the battery internal resistance detection circuit 100. The battery internal resistance detection method includes:

Step S1: Determine the capacity range of the battery to be tested.

Determine the capacity range of the battery to be tested, and use a targeted battery internal resistance detection method to detect the internal resistance of the battery to be tested.

Step S2: Determine the detection logic of the battery to be tested according to the capacity range of the battery to be tested.

The detection logic includes how to charge and discharge the battery to be tested, and how to process the data during the charging and discharging process of the battery to be tested, so as to finally calculate the internal resistance of the battery to be tested.

For the batteries to be tested in different capacity ranges, different detection logics are used to detect the internal resistance, so that more accurate results can be obtained.

Step S3: Obtain the voltage and current of the battery to be tested according to the detection logic.

Specifically, the battery to be tested is first charged or discharged according to the detection logic, and then the voltage or current of the battery to be tested is collected.

Step S4: Output the internal resistance of the battery to be tested according to the detection logic, the voltage and the current.

Please refer to FIG. 3 , which is a schematic flowchart of determining the detection logic of the battery to be tested according to an embodiment of the present application. In some embodiments, the detection logic includes first logic and second logic, the capacity range includes a first capacity range and a second capacity range, and the battery to be tested is determined based on the capacity range of the battery to be tested. The battery detection logic includes:

Step S21: When the capacity range of the battery to be tested is within the first capacity range, determine to use the first logic to detect the internal resistance of the battery to be tested.

Step S22: When the capacity range of the battery to be tested is within the second capacity range, determine to use the second logic to detect the internal resistance of the battery to be tested.

The division standard of the first capacity range and the second capacity range can be determined according to actual needs. For example, the first capacity range is 0AH to 20AH (excluding 20AH), and the second capacity range is greater than or equal to 20AH. That is, the batteries to be tested in the first capacity range include batteries whose internal resistance is usually measured using the ACIR (Alternating Current Internal Resistance) method, and the batteries to be tested in the second capacity range include batteries whose internal resistance is usually measured using DCIR (Direct Current Internal Resistance, DC internal resistance) test method to measure the internal resistance of the battery.

Please refer to FIG. 4 , which is a schematic flowchart of obtaining the voltage and current of the battery to be tested according to an embodiment of the present application. Specifically, the first logic includes a first charging logic and a first discharging logic, the second logic includes a second charging logic and a second discharging logic, and the voltage of the battery to be tested includes the first charging voltage V _a ( i), the second charging voltage V _b , the first discharging voltage V _c (i) and the second discharging voltage V _d , the current of the battery to be tested includes the first charging current I _a (i), the second charging current I _b . The first discharge current I _c (i) and the second discharge current I _d . In some embodiments, obtaining the voltage and current of the battery under test according to the detection logic includes:

Step S31: When the capacity range of the battery to be tested is within the first capacity range, obtain the first charging voltage and the first charging current of the battery to be tested according to the first charging logic. A discharge logic obtains the first discharge voltage and the first discharge current of the battery under test.

Step S32: When the capacity range of the battery to be tested is within the second capacity range, obtain the second charging voltage and the second charging current of the battery to be tested according to the second charging logic. The second discharge logic acquires the second discharge voltage and the second discharge current of the battery under test.

Please refer to FIG. 5 , which is a schematic flowchart of outputting the internal resistance of the battery under test provided by an embodiment of the present application. In some embodiments, the internal resistance of the battery to be tested includes a charging internal resistance R _α and a discharging internal resistance R _β . According to the detection logic, the voltage and the current, the output of the battery to be tested is Internal resistance includes:

Step S41: When the capacity range of the battery under test is within the first capacity range, calculate the charge of the battery under test according to the first charging logic, the first charging voltage and the first charging current. Internal resistance: calculate the discharge internal resistance of the battery to be tested based on the first discharge logic, the first discharge voltage and the first discharge current.

Step S42: When the capacity range of the battery to be tested is within the second capacity range, calculate the charging of the battery to be tested based on the second charging logic, the second charging voltage and the second charging current. Internal resistance: calculate the internal discharge resistance of the battery to be tested according to the second discharge logic, the second discharge voltage and the second discharge current.

Specifically, the first charging logic is: first, charge the battery under test in the first capacity range by inputting a PWM waveform signal, and collect the first charging voltage V _{a (i) and the first charging voltage V a} (i) in the charging process in real time. The first charging current I _a (i) is calculated as follows, and then the charging internal resistance R _α of the battery to be tested is calculated according to the following formula:
V _a (I)＝ε+I _a (i)·R _α (1)

Where, ε is the open circuit voltage of the battery under test.

In actual detection, the first charging voltage V _a (i) and the first charging current I _a (i) in the above formula (1) can take the effective value of the first charging voltage and the effective value of the first charging current and The calculation formula is as follows:

Among them, N is an integer greater than or equal to 1.

The first discharge logic is: first control the discharge of the battery to be tested in the first capacity range, and collect the first discharge voltage V _c (i) and the first discharge current I _c (i) during the discharge process in real time. ), and then calculate the discharge internal resistance R _β of the battery to be tested according to the following formula:

Where, ε is the open circuit voltage of the battery under test.

The second charging logic is: first, two kinds of direct current, a first direct current and a second direct current, are alternately input to the battery to be tested in the second capacity range, and the voltages of the first direct current and the second direct current are different. The second charging voltage V _b and the second charging current I _b during the charging process are collected in real time. The second charging voltage V _b includes the voltage V _b1 input to the first DC collection and the voltage V _b2 input to the second DC collection, so The second charging current I _b includes I _b1 input to the first direct current collection and I _b2 input to the second direct current collection, and then the following formula is used to calculate the charging internal resistance R _α of the battery under test:

When detecting the internal resistance of the battery to be tested in the second capacity range, two kinds of direct current, the first direct current and the second direct current, need to be input alternately. The alternating frequency of the first direct current and the second direct current cannot be too high, and is generally set to about 10Hz.

In the first charging logic and the second charging logic, the measurement signal uses a PWM alternating signal, which reduces the influence of other calculation factors and makes the calculation method more reliable. The measured values are averaged through calculations over multiple cycles to improve the stability of the measurement results. The measurement signal uses different frequencies according to the battery capacity. Small-capacity batteries use high frequency for detection, and large-capacity batteries use low frequency to reduce the impact of frequency changes on the sampling signal.

The second discharge logic is: connect resistors R1 and resistor R2 in parallel at both ends of the battery to be tested in the second capacity range, first control the battery to be tested to periodically switch the connection between the resistor R1 and the resistor R2. Discharge. The second discharge voltage V _d and the second discharge current I _d are collected in real time during the charging process. The second discharge voltage V _d includes the voltage V d1 collected by the battery under test discharging to the resistor R1 and the voltage V _d under test. The voltage V _d2 collected by the battery discharging to the resistor R2, and the second discharge current I _d includes the current I d1 collected by the battery under test discharging to the resistor R1 and the current I _d1 collected by the battery under test discharging to the resistor R2. The collected current I _d2 is then used to calculate the discharge internal resistance R _β of the battery to be tested using the following formula:

The battery internal resistance detection method provided by the embodiment of the present application determines the capacity range of the battery to be tested, determines the detection logic of the battery to be tested based on the capacity range of the battery to be tested, and obtains the battery to be tested based on the detection logic. According to the voltage and current of the battery, the internal resistance of the battery to be tested is output based on the detection logic, the voltage and the current. The battery internal resistance detection method provided in this embodiment integrates two battery internal resistance measurement technologies. Different testing methods are used according to the battery capacity. Large-capacity batteries are measured using the two-stage DCIR method, and small-capacity batteries use the effective value method of alternating signals. Measure, improve measurement accuracy and ensure battery safety. At the same time, the battery internal resistance detection method provided in this embodiment supports independent testing of charging internal resistance and discharging internal resistance. The measured values can better meet the actual computing application scenarios and are more representative of battery performance analysis.

Please refer to FIG. 6 , which is a schematic structural diagram of a battery internal resistance detection circuit provided by an embodiment of the present application.

The embodiment of the present application provides a battery internal resistance detection circuit 100, which includes a power module 10, a detection module 20, a control module 30, and a sampling module 40. The power module 10 is connected to the detection module 20, the control module 30, and The sampling module 40 is connected to the battery 200 to be tested. The control module 30 is connected to the detection module 20 and the sampling module 40 respectively. The detection module 20 and the sampling module 40 are respectively connected to the battery to be tested. 200 connection, the power module 10 is used to provide power for the detection module 20, the control module 30, the sampling module 40 and the battery to be tested 200; the detection module 20 is used to provide power according to the control module The instruction of 30 is to detect the internal resistance of the battery 200 under test in the first capacity range or the internal resistance of the battery 200 under test in the second capacity range; the sampling module 40 is used to collect the voltage and voltage of the battery 200 under test. Current; the control module 30 is used to perform the battery internal resistance detection method as described above.

Please refer to FIG. 7 , which is a schematic circuit structure diagram of a battery internal resistance detection circuit provided by an embodiment of the present application. In some embodiments, the detection module 10 includes a first detection unit 201 and a second detection unit 202. The first detection unit 201 is connected to the power module 10 and the battery to be tested 200 respectively. Two detection units 202 are respectively connected to the power module 10 and the battery to be tested 200. The first detection unit 201 is used to detect the battery 200 to be tested in the first capacity range; the second detection unit 202 uses To detect the battery 200 under test in the second capacity range.

In some embodiments, the sampling module 40 includes a sensor unit 401, an operational amplifier unit 402, a data sampling unit 403 and a signal processing unit 404. The sensor unit 401 is connected to the battery to be tested 200 and the operational amplifier unit respectively. 402 connection, the operational amplifier unit 402 is connected to the data sampling unit 403, the data sampling unit 403 is connected to the signal processing unit 404, the signal processing unit 404 is connected to the control module 30, the sensor Unit 401 is used to collect the current signal and voltage signal of the battery 200 under test; the operational amplifier unit 402 is used to remove interference from the collected current signal and voltage signal; and the data acquisition unit 403 is used to Sample the current signal after interference removal and the voltage signal after interference removal to obtain a sampled current signal and a sampled voltage signal; the signal processing unit 404 is used to perform signal processing on the sampled current signal and the sampled voltage signal. Process to obtain the current and voltage of the battery 200 under test.

In some embodiments, the sensor unit 404 includes a current sensor 4011 and a voltage sensor 4012. The current sensor 4011 is connected in series with the battery 200 under test, and the voltage sensor 4012 is connected in parallel with the battery 200 under test.

Specifically, the control module 30 may be a microcontroller unit (MCU), also known as a single chip microcomputer (Single Chip Microcomputer) or a single chip microcomputer.

The operational amplifier unit 402 suppresses the clutter of the collected current signal and voltage signal, configures different gains for the current signal and the voltage signal, and supports the current signal and the voltage signal. The sampling range is wide and the accuracy is high, reducing the impact of interference.

The data sampling unit 403 may be an ADC (Analog-to-Digital Converter, analog-to-digital converter or analog-to-digital converter), which converts continuous variable analog signals into discrete digital signals. The signal processing unit 404 may be a Field Programmable Gate Array (FPGA). Because the detection signal of the battery under test in the first capacity range changes very quickly, usually above 1 KHz, a multi-channel high-speed ADC is used for sampling, and the FPGA performs post-sampling signal processing. For the battery to be tested in the second capacity range, the detection current is large, the power output is correspondingly slow, and the change frequency cannot be too high. The frequency of the power supply can be set at about 10 Hz.

In the embodiment of this application, technologies such as time domain sorting and FFT (Fast Fourier Transform) high-frequency filtering are used to eliminate the influence of sampling transient signals and clutter, making the calculation results more reliable and improving the consistency of the measurement results. Signal processing is implemented using high-speed ADC and FPGA to improve data processing speed and ensure the reliability of analyzed data.

In some embodiments, the battery internal resistance detection circuit 100 also includes a communication module (not shown). The communication module is connected to the control module 30. The communication module is used to communicate with the cloud server and can receive and send data. In some embodiments, the battery internal resistance detection circuit 100 further includes an interactive module (not shown), the interactive module is connected to the control module 30 , and the interactive module is used to receive instructions input by the user to the Control module 30. The control module 30 can input the capacity of the battery to be tested 200 and the charging and discharging current of the battery to be tested 200 from the interactive module or obtain it from the cloud platform through the communication module. The control module 30 can automatically detect the battery voltage range and output an optimized detection voltage to prevent damage to the battery and make detection safer.

Please refer to FIG. 8 , which is a schematic circuit structure diagram of the first detection unit provided by an embodiment of the present application. In some embodiments, the first detection unit 201 includes a switch 1, a switch 2, a switch Q1, a switch Q2, and a resistor stack a. The second end of the switch 1 is connected to the first end of the switch Q1, so The second end of the switch Q1 is connected to the power module 10, and the first end of the switch 1 is connected to the first end of the switch 2 and the first end of the battery 200 to be tested respectively. The switch 2 The second end of the switch Q2 is connected to the first end of the switch Q2. The second end of the switch Q2 is connected to the first end of the resistor stack a. The second end of the resistor stack a is respectively connected to the power module. 10 is connected to the second end of the battery 200 under test.

Specifically, the control terminals of the switch Q2 are connected to the control module 30, and the control module 30 can control the on and off of the switch 1, the switch 2, the switch Q1, and the switch Q2. The switch 1 and the switch 2 can be said to be relatively simple controllable switches, and the switch Q1 and the switch Q2 can be switches composed of field effect transistors.

When detecting the charging internal resistance of the battery 200 under test in the first capacity range, the control module controls the switch 1 to turn on, and the When the switch 2 is turned off and the switch Q2 is turned off, the switch Q1 is controlled to turn on and off according to the corresponding frequency to form a PWM waveform signal.

When detecting the discharge internal resistance of the battery 200 under test in the first capacity range, the control module controls the switch 1 to turn off, the switch 2 to turn on, the switch Q1 to turn off, and controls the switch Q2 to follow the corresponding frequency. Turn on and off to measure the discharge internal resistance of the battery under test.

In this embodiment, the switch 1 and the switch 2 are used to eliminate the influence of components such as capacitors in the switch Q1 and the switch Q2, thereby making the measured internal resistance more accurate.

The resistor stack a is composed of multiple resistors connected in series, and each resistor is connected in parallel with a switch. Whether the resistor is connected in series to the loop can be controlled through the switch. Different series combinations of resistors can achieve different resistance values. The discharge resistor is constructed from a resistor stack a. According to different discharge currents, two resistor combinations are constructed in the resistor stack a. During discharge, the two combinations are switched to construct different output currents. The charging internal resistance and discharging internal resistance of multiple groups of batteries to be tested can be measured, so that more accurate results can be obtained by taking average values, etc.

Please refer to FIG. 9 , which is a schematic circuit structure diagram of the second detection unit provided by an embodiment of the present application. In some embodiments, the second detection unit 202 includes switch 3, switch 4, switch 5, switch Q3, switch Q4, switch Q5, resistor stack b, resistor stack c, the first end of the switch 3 is connected to the The first end of the switch Q3 is connected to the power module 10. The second end of the switch 3 is connected to the first end of the switch 4 and the third end of the switch 5 respectively. One end is connected to the battery 200 to be tested, the second end of the switch 4 is connected to the first end of the switch Q4, the second end of the switch Q4 is connected to the first end of the resistor stack b, The second end of the switch 5 is connected to the first end of the switch Q5, the second end of the switch Q5 is connected to the first end of the resistor stack c, and the second end of the battery to be tested 200 is respectively It is connected to the power module 10, the second end of the resistor stack b and the second end of the resistor stack c.

When detecting the charging internal resistance of the battery 200 under test in the second capacity range, the control module controls the switch 3 to be turned on, the switch 4 to be turned off, the switch 5 to be turned off, and the switch Q3 to be turned on. When the switch Q4 is turned on and the switch Q5 is turned off, the power module 10 is controlled to alternately output two sets of direct currents with different voltages.

When detecting the discharge internal resistance of the battery 200 under test in the second capacity range, the control module controls the switch 3 to be turned off, the switch 4 to be turned on, the switch 5 to be turned on, and the switch Q3 to be turned off. On, the switch Q4 and the switch Q5 are controlled to be turned on alternately according to the corresponding frequency.

In this embodiment, the switch 3, the switch 4 and the switch 5 are used to eliminate the influence of the capacitance and other devices in the switch Q3, the switch Q4 and the switch Q5, so that the measurement can be The internal resistance is more accurate.

The resistor stack b and the resistor stack c are connected in series by a plurality of resistors, and each resistor is connected in parallel with a switch. Whether the resistors are connected in series to the loop can be controlled by the switch. Different series combinations of resistors can achieve different resistance values. The discharge resistor is constructed from the resistor stack b and the resistor stack c. According to different discharge currents, during discharge, the two combinations are switched to construct different output currents. At the same time, the charging internal resistance and discharging internal resistance of multiple groups of batteries to be tested can be measured, so that more accurate results can be obtained by averaging and the like.

In this embodiment, the internal resistance of the battery to be tested is usually relatively small, and small changes in charging voltage will cause large fluctuations in current. The power signal input to the battery to be tested must ensure that the detected current is within a safe range. Set the starting voltage of the power supply output to the open circuit voltage of the battery. At this time, the output current is 0. Gradually increase the voltage of the power supply while detecting the output current. When the output current reaches the target detection current of the battery, it will no longer increase. The voltage of the power supply. At this time, the voltage of the power supply can be used as the power supply voltage when measuring the charging internal resistance of the battery to be tested.

Please refer to Figure 10, which is a schematic diagram of the voltage change when the switch Q1 is turned on.

In the embodiment of the present application, during the process of the switch Q1 and the switch Q3 being turned on or off, the voltage of the power supply will have an impact and generate a transient voltage. As shown in Figure 10, the t0-t1 stage is affected by the turn-on impact. Affected, the voltage has a sudden change. The voltage between the t2-t3 segments also undergoes a sudden change due to the shutdown. In order to eliminate this effect, the sampled data needs to be filtered. There are usually two filtering methods, one is time domain filtering, and the sampling point is the data between t1 and t2. Another filtering method is frequency domain filtering. The data is first transformed into the frequency domain through fast Fourier transform, and high-frequency interference components are filtered out to obtain a stable voltage value. All filtering algorithms are processed within the FPGA to ensure timely processing. In actual processing, for the sampled data in a cycle, the time domain filtering method can remove the first several data and the last several data, and then average the remaining data to obtain the sampled value of the cycle.

The battery internal resistance detection circuit provided in the embodiment of the present application includes a power module, a detection module, a control module, and a sampling module. The power module is respectively connected to the detection module, the control module, the sampling module, and the battery to be tested. connection, the control module is respectively connected to the detection module and the sampling module, the detection module and the sampling module are respectively connected to the battery to be tested, and the power module is used to provide power to the detection module and the sampling module. The control module, the sampling module and the battery to be tested provide power; the detection module is used to According to the instruction of the control module, the internal resistance of the battery to be tested in the first capacity range or the internal resistance of the battery to be tested in the second capacity range is detected; the sampling module is used to collect the voltage and voltage of the battery to be tested. Current; the control module is used to perform the battery internal resistance detection method as described above. By performing targeted internal resistance detection on the battery to be tested, the accuracy of battery internal resistance detection can be improved.

An embodiment of the present application also provides a battery internal resistance detection device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores information that can be used by the at least one processor. Instructions executed by the processor. The instructions are executed by the at least one processor so that the at least one processor can execute the battery internal resistance detection method.

Embodiments of the present application also provide a computer-readable storage medium. The computer-readable storage medium stores computer-executable instructions. The computer-executable instructions are used to cause the computer to execute the battery internal resistance detection method.

Embodiments of the present application also provide a computer program product, which includes a computing program stored on a non-volatile computer-readable storage medium. The computer program includes program instructions that, when executed by a computer, cause all The computer executes the battery internal resistance detection method in any of the above method embodiments.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit it; under the idea of the present application, the technical features of the above embodiments or different embodiments can also be combined. The steps may be performed in any order, and there are many other variations of different aspects of the application as described above, which are not provided in detail for the sake of brevity; although the application has been described in detail with reference to the foregoing embodiments, one of ordinary skill in the art Skilled persons should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the implementation of the present application. Example scope of technical solutions.

The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application. should be covered by the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claims.

Claims

A battery internal resistance detection method, including:

Determine the capacity range of the battery to be tested;

Determine the detection logic of the battery to be tested according to the capacity range of the battery to be tested;

Obtain the voltage and current of the battery to be tested according to the detection logic;

According to the detection logic, the voltage and the current, the internal resistance of the battery to be tested is output.
The battery internal resistance detection method according to claim 1, the detection logic includes first logic and second logic, the capacity range includes a first capacity range and a second capacity range, and the battery is tested according to the The detection logic for determining the capacity range of the battery to be tested includes:

When the capacity range of the battery to be tested is within the first capacity range, determine to use the first logic to detect the internal resistance of the battery to be tested;

When the capacity range of the battery to be tested is within the second capacity range, it is determined to use the second logic to detect the internal resistance of the battery to be tested.
The battery internal resistance detection method according to claim 2, the first logic includes a first charging logic and a first discharging logic, the second logic includes a second charging logic and a second discharging logic, and the battery to be tested The voltage includes a first charging voltage, a second charging voltage, a first discharging voltage and a second discharging voltage, and the current of the battery under test includes a first charging current, a second charging current, a first discharging current and a second discharging current. , obtaining the voltage and current of the battery to be tested according to the detection logic includes:

When the capacity range of the battery to be tested is within the first capacity range, the first charging voltage and the first charging current of the battery to be tested are obtained according to the first charging logic, and the first charging current is obtained according to the first discharging logic. Obtain the first discharge voltage and the first discharge current of the battery under test;

When the capacity range of the battery to be tested is within the second capacity range, the second charging voltage and the second charging current of the battery to be tested are obtained according to the second charging logic, and the second charging current is obtained according to the second discharging logic. Obtain the second discharge voltage and the second discharge current of the battery under test.
The battery internal resistance detection method according to claim 3, the internal resistance of the battery to be tested includes a charging internal resistance and a discharging internal resistance, and based on the detection logic, the voltage and the current, the battery to be tested is output. Measuring the internal resistance of the battery includes:

When the capacity range of the battery to be tested is within the first capacity range, the charging internal resistance of the battery to be tested is calculated according to the first charging logic, the first charging voltage and the first charging current, Calculate the discharge internal resistance of the battery to be tested according to the first discharge logic, the first discharge voltage and the first discharge current;

When the capacity range of the battery to be tested is within the second capacity range, the charging internal resistance of the battery to be tested is calculated according to the second charging logic, the second charging voltage and the second charging current, The discharge internal resistance of the battery to be tested is calculated according to the second discharge logic, the second discharge voltage and the second discharge current.
A battery internal resistance detection circuit includes a power module, a detection module, a control module, and a sampling module. The power module is connected to the detection module, the control module, the sampling module and the battery to be tested respectively. The control module The modules are respectively connected to the detection module and the sampling module, and the detection module and the sampling module are respectively connected to the battery to be tested,

The power module is used to provide power for the detection module, the control module, the sampling module and the battery to be tested;

The detection module is configured to detect the internal resistance of the battery to be tested in the first capacity range or the internal resistance of the battery to be tested in the second capacity range according to instructions from the control module;

The sampling module is used to collect the voltage and current of the battery to be tested;

The control module is used to execute the battery internal resistance detection method according to any one of claims 1 to 4.
The battery internal resistance detection circuit according to claim 5, the detection module includes a first detection unit and a second detection unit, the first detection unit is connected to the power module and the battery to be tested respectively, and the The second detection unit is respectively connected to the power module and the battery to be tested,

The first detection unit is used to detect the battery to be tested in the first capacity range;

The second detection unit is used to detect the battery to be tested in the second capacity range.
The battery internal resistance detection circuit according to claim 6, the first detection unit includes switch 1, switch 2, switch Q1, switch Q2, and resistor stack a,

The second end of the switch 1 is connected to the first end of the switch Q1, the second end of the switch Q1 is connected to the power module, and the first end of the switch 1 is respectively connected to the third end of the switch 2. One end is connected to the first end of the battery to be tested, the second end of the switch 2 is connected to the first end of the switch Q2, and the second end of the switch Q2 is connected to the first end of the resistor stack a. The second end of the resistor stack a is connected to the second end of the power module and the battery to be tested respectively.
The battery internal resistance detection circuit according to claim 6, the second detection unit includes switch 3, switch 4, switch 5, switch Q3, switch Q4, switch Q5, resistor stack b, resistor stack c,

The first end of the switch 3 is connected to the first end of the switch Q3, the first end of the switch Q3 is connected to the power module, and the second end of the switch 3 is respectively connected to the third end of the switch 4. One end, the first end of the switch 5 is connected to the battery to be tested, the second end of the switch 4 is connected to the first end of the switch Q4, and the second end of the switch Q4 is connected to the resistor. The first end of the stack b is connected, the second end of the switch 5 is connected to the first end of the switch Q5, the second end of the switch Q5 is connected to the first end of the resistor stack c, and the waiting The second end of the test battery is connected to the power module, the second end of the resistor stack b and the second end of the resistor stack c respectively.
The battery internal resistance detection circuit according to claim 5, the sampling module includes a sensor unit, an operational amplifier unit, a data sampling unit and a signal processing unit, the sensor unit is connected to the battery to be tested and the operational amplifier unit respectively. connection, the operational amplifier unit is connected to the data sampling unit, the data sampling unit is connected to the signal processing unit, the signal processing unit is connected to the control module,

The sensor unit is used to collect the current signal and voltage signal of the battery to be tested;

The operational amplifier unit is used to remove interference from the collected current signal and voltage signal;

The data acquisition unit is used to sample the current signal after interference removal and the voltage signal after interference removal, and obtain the sampled current signal and the sampled voltage signal;

The signal processing unit is used to perform signal processing on the sampled current signal and the sampled voltage signal to obtain the current and voltage of the battery to be tested.
The battery internal resistance detection circuit according to claim 9, the sensor unit includes a current sensor and a voltage sensor, the current sensor is connected in series with the battery to be tested, and the voltage sensor is connected in parallel with the battery to be tested.
A battery internal resistance detection device, including: at least one processor; and,

a memory communicatively connected to the at least one processor; wherein,

The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor, so that the at least one processor can perform as described in any one of claims 1-4 Methods.
A computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to cause a computer to execute the method according to any one of claims 1-4.