Battery internal resistance detection circuit

By combining isolation units, signal amplification units, and microcontrollers, the problems of large errors and environmental influences in traditional battery internal resistance testing methods are solved, achieving high-precision battery internal resistance detection.

CN223650711UActive Publication Date: 2025-12-09AWELL (GUANGDONG) ELECTRONICS CO LTD
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Patent Information

Application Number
CN202422917296.5
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-11-28
Publication Date
2025-12-09
Estimated Expiration
2034-11-28

AI Technical Summary

Technical Problem

Traditional battery internal resistance testing methods have large errors, slow testing speed, and the test results are easily affected by the environment.

Method used

The system employs an isolation unit, a signal amplification unit, a signal detection unit, and a microcontroller. It isolates external environmental interference, uses the signal amplification unit to detect the battery's internal resistance signal, and performs digital filtering processing through the microcontroller.

Benefits of technology

It improves the accuracy of battery internal resistance testing, reduces the impact of the environment on test results, and enhances the ease of identifying abnormal and normal products.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model belongs to the technical field of batteries, and particularly discloses a battery internal resistance detection circuit which comprises an isolation unit, a signal amplification unit, a signal detection unit, a single chip microcomputer and an abnormal on-off control unit. The single-chip microcomputer is electrically connected with the isolation unit, the signal amplification unit, the signal detection unit and the abnormal on-off control unit, and the isolation unit, the signal amplification unit, the signal detection unit and the single-chip microcomputer are matched, so that signal feedback is performed on the internal resistance of the battery through the isolation unit; and meanwhile, interference of an external environment on resistance feedback can be isolated, an internal resistance signal of the battery is detected by utilizing the signal amplification unit and then is amplified by the signal detection unit, and the acquired signal is digitally filtered by the single chip microcomputer, so that the test precision is effectively improved, and the influence of the environment on a test result is reduced.
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Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a battery internal resistance detection circuit. Background Technology

[0002] Batteries are ubiquitous in daily life and production. From mobile phones to charging devices, batteries are essential. The most common type is the 18650 battery, favored for its ease of use and ability to be assembled into different voltage specifications. A crucial factor in determining a battery's quality is its internal resistance. Higher internal resistance results in poorer battery performance, higher energy consumption, and shorter lifespan. Conversely, lower internal resistance leads to longer battery life and greater durability. Traditional testing methods involve measuring the voltage across the terminals with a multimeter and then determining if the internal resistance is within a reasonable range. This method suffers from significant errors, slow testing speed, and environmental influences, leading to abnormal results. Therefore, we need to propose a battery internal resistance detection circuit to address these issues, improving testing accuracy while minimizing environmental impact on test results. Utility Model Content

[0003] The purpose of this invention is to provide a battery internal resistance detection circuit that can improve testing accuracy while reducing the impact of the environment on test results, thereby solving the problems mentioned in the background art.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a battery internal resistance detection circuit, comprising an isolation unit, a signal amplification unit, a signal detection unit, a microcontroller, and an abnormal on / off control unit. The signal detection unit is electrically connected to the isolation unit and the signal amplification unit, respectively. The abnormal on / off control unit is electrically connected to the isolation unit, and the microcontroller is electrically connected to the isolation unit, the signal amplification unit, the signal detection unit, and the abnormal on / off control unit, respectively.

[0005] Preferably, the microcontroller is configured as an STM32F chip U3. A crystal oscillator Y1 and a resistor R41 are connected in parallel between pins 2 and 3 of the STM32F chip U3. Capacitors C31 and C32 are connected to the two ends of the crystal oscillator Y1, respectively. One end of capacitor C31 and one end of capacitor C32 are grounded. A resistor R11 and a diode D4 are connected in parallel between pins 4 of the STM32F chip U3. One end of diode D4 is connected to capacitor C5. One end of capacitor C5 is connected to pin 5 of the STM32F chip U3 through capacitor C4. A capacitor C3 is connected between pins 31 and 32 of the STM32F chip U3. A resistor R9 is also connected to ground at pin 31 of the STM32F chip U3.

[0006] Preferably, the isolation unit includes an optocoupler U2, pins 1 and 3 of which are connected; pin 2 of which is connected to pin 18 of the microcontroller via resistor R7; pin 4 of which is connected to pin 13 of the microcontroller via resistor R10; pin 8 of which is connected to resistor R6; one end of resistor R6 is connected to resistor R14; one end of resistor R14 is connected to amplifier U4; the output of amplifier U4 is connected in series with capacitor C28 and resistor R12; one end of resistor R12 is connected to a signal detection unit; diodes D3 and D2 are connected in parallel between the output of amplifier U4 and its negative terminal; one of the terminals of diodes D3 and D2 is connected to an abnormal on / off control unit; the connection between resistors R14 and R6 is connected to a grounding resistor R13; and pin 5 of optocoupler U2 is connected to the connection between resistors R14 and R6.

[0007] Preferably, the abnormal on / off control unit includes a relay K1. A diode D1 is connected between pins 1 and 2 of the relay K1. A transistor Q1 is connected to pin 1 of the relay K1. The base of the transistor Q1 is connected to the microcontroller through a resistor R1. A resistor R37 is connected between the base and emitter of the transistor Q1. A resistor R36 for connecting an 8V voltage is also connected to pin 2 of the relay K1. A resistor R4 is connected to pin 5 of the relay K1. A resistor R5 is connected to pin 4 of the relay K1. One end of each of the resistors R4 and R5 is connected to a signal detection unit.

[0008] Preferably, the signal amplification unit includes amplifier U6 and amplifier U5. A diode D7 and a series diode D8 and a resistor R32 are connected in parallel between the output terminal and the negative terminal of amplifier U6. A resistor R19 is connected to the connection terminal of diode D8 and resistor R32. A capacitor C29, a resistor R26, and a capacitor C27 are connected in parallel to one end of resistor R19. A resistor R34 is connected to one connection terminal of capacitor C27 and resistor R26. A resistor R17 is connected to ground to the connection terminal of resistor R19 and capacitor C27. A resistor R29, a resistor R30, and a capacitor C17 are connected in parallel between the negative terminal and the output terminal of amplifier U5. A capacitor C9 is connected to the output terminal of amplifier U5. One end of capacitor C9 is connected to the positive terminal of amplifier U6 through resistor R18. A capacitor C15 and a resistor R25 are also connected in parallel to the negative terminal of amplifier U5. The positive terminal of amplifier U5 is connected to the signal detection unit.

[0009] Preferably, the signal detection unit includes an amplifier U7. The output terminal of the amplifier U7 is connected in series with resistors R27 and R31. The positive terminal of the amplifier U7 is connected to a resistor R24. One end of the resistor R24 ​​is connected to a terminal J3. A capacitor C7 and a capacitor C8 are connected in parallel between pins 3 and 4 of the terminal J3. A resistor R23 and a capacitor C6 are connected in series. A resistor R22, a diode D6, and a diode D5 are connected in parallel to the resistor R23. A capacitor C10 is connected to one of the connection terminals of the resistors R22 and R23. A ground resistor R20 and a ground resistor R28 are connected in parallel to the connection terminal of the amplifier U7 and the resistor R24.

[0010] Compared with the prior art, the beneficial effects of this utility model are:

[0011] 1. This utility model utilizes the cooperation of an isolation unit, a signal amplification unit, a signal detection unit, and a microcontroller. The isolation unit provides signal feedback on the battery's internal resistance while also isolating external environmental interference from the resistance feedback. The signal amplification unit detects the battery's internal resistance signal, which is then amplified by the signal detection unit. The microcontroller performs digital filtering on the acquired signal, effectively improving test accuracy while reducing the impact of the environment on the test results.

[0012] 2. This utility model, through the cooperation of an abnormal on / off control unit, an isolation unit and a microcontroller, can set a standard product judgment range through the microcontroller. When the detection result is within the standard product judgment range, the good product alarm channel is turned on. When the detection result exceeds the standard product judgment range, the abnormal product channel is turned on, thereby improving the convenience of identifying abnormal and normal products. Attached Figure Description

[0013] Figure 1 This is a circuit connection block diagram of the present invention;

[0014] Figure 2 This is a circuit diagram of the isolation unit of this utility model;

[0015] Figure 3 This is a circuit diagram of the signal amplification unit of this utility model;

[0016] Figure 4 This is a circuit diagram of the signal detection unit of this utility model;

[0017] Figure 5 This is a circuit diagram of the abnormal on / off control unit of this utility model;

[0018] Figure 6 This is the circuit diagram of the microcontroller of this utility model. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Please see Figure 1-6 This utility model provides a technical solution: a battery internal resistance detection circuit, including an isolation unit, a signal amplification unit, a signal detection unit, a microcontroller, and an abnormal on / off control unit. The signal detection unit is electrically connected to the isolation unit and the signal amplification unit, respectively. The abnormal on / off control unit is electrically connected to the isolation unit, and the microcontroller is electrically connected to the isolation unit, the signal amplification unit, the signal detection unit, and the abnormal on / off control unit, respectively.

[0021] The microcontroller is configured as an STM32F chip U3. A crystal oscillator Y1 and a resistor R41 are connected in parallel between pins 2 and 3 of the STM32F chip U3. Capacitors C31 and C32 are connected to the two ends of crystal oscillator Y1, respectively, with one end of each capacitor grounded. A resistor R11 and a diode D4 are connected in parallel between pin 4 of the STM32F chip U3. One end of diode D4 is connected to capacitor C5, and one end of capacitor C5 is connected to STM32F chip U3 via capacitor C4. Pin 5 of the STM32F chip U3 is connected, and a capacitor C3 is connected between pins 31 and 32 of the STM32F chip U3. Pin 31 of the STM32F chip U3 is also connected to a resistor R9 to ground. A crystal oscillator Y1 and a resistor R41 are connected in parallel between pins 2 and 3 of the STM32F103 chip to form a typical RL filter circuit. This circuit facilitates digital filtering of the acquired signal by a microcontroller, effectively improving test accuracy while reducing the impact of the environment on the test results.

[0022] The isolation unit includes an optocoupler U2. Pins 1 and 3 of the optocoupler U2 are connected. Pin 2 of the optocoupler U2 is connected to pin 18 of the microcontroller via resistor R7. Pin 4 of the optocoupler U2 is connected to pin 13 of the microcontroller via resistor R10. Pin 8 of the optocoupler U2 is connected to resistor R6. One end of resistor R6 is connected to resistor R14. One end of resistor R14 is connected to amplifier U4. The output terminal of amplifier U4 is connected in series with capacitor C28 and resistor R12. One end of resistor R12 is connected to the signal detection unit. Diodes D3 and D2 are connected in parallel between the output terminal and the negative terminal of amplifier U4. One of the connection terminals of diodes D3 and D2 is connected to the abnormal on / off control unit. The connection terminal of resistors R14 and R6 is connected to grounding resistor R13. Pin 5 of optocoupler U2 is connected to the connection terminal of resistors R14 and R6. Optocoupler U2 is used to isolate interference from external signals and also provides signal feedback on the battery's internal resistance.

[0023] The abnormal on / off control unit includes a relay K1. A diode D1 is connected between pins 1 and 2 of the relay K1. A transistor Q1 is connected to pin 1 of the relay K1. The base of the transistor Q1 is connected to the microcontroller through a resistor R1. A resistor R37 is connected between the base and emitter of the transistor Q1. A resistor R36 for connecting an 8V voltage is also connected to pin 2 of the relay K1. A resistor R4 is connected to pin 5 of the relay K1. A resistor R5 is connected to pin 4 of the relay K1. One end of each of the resistors R4 and R5 is connected to a signal detection unit. The microcontroller controls the on / off state of each control pin of the relay K1 and the transistor Q1, thereby controlling the conduction and cutoff of different channels. A standard product judgment range is set by the microcontroller. When the detection result is within the standard product judgment range, the good product alarm channel is activated. When the detection result exceeds the standard product judgment range, the abnormal product channel is activated, improving the convenience of identifying abnormal and normal products.

[0024] The signal amplification unit includes amplifier U6 and amplifier U5. A diode D7 and a series diode D8 and resistor R32 are connected in parallel between the output terminal and the negative terminal of amplifier U6. A resistor R19 is connected to the connection point of diode D8 and resistor R32. A capacitor C29, a resistor R26, and a capacitor C27 are connected in parallel to one end of resistor R19. A resistor R34 is connected to one of the connection points of capacitor C27 and resistor R26. A ground resistor R1 is connected to the connection point of resistor R19 and capacitor C27. 7. Resistors R29 and R30, and capacitor C17 are connected in parallel between the negative terminal and the output terminal of amplifier U5. Capacitor C9 is connected to the output terminal of amplifier U5. One end of capacitor C9 is connected to the positive terminal of amplifier U6 through resistor R18. Capacitor C15 and resistor R25, arranged in parallel, are also connected to the negative terminal of amplifier U5. The positive terminal of amplifier U5 is connected to the signal detection unit. Amplifiers U6 and U5, as the core components of the signal amplification unit, are responsible for receiving and amplifying the input signal. By adjusting the amplifier gain, sufficient amplitude is ensured for the signal in subsequent processing, thereby improving the sensitivity and accuracy of signal detection. The RC filter circuit composed of resistor R30 and capacitor C17 can effectively suppress high-frequency noise and retain useful low-frequency signals. Simultaneously, diode D7, diode D8 arranged in series, and resistor R32 also play a certain limiting role, preventing excessively large signals from damaging subsequent circuits.

[0025] The signal detection unit includes an amplifier U7. Resistors R27 and R31 are connected in series at the output of amplifier U7. Resistor R24 ​​is connected to the positive terminal of amplifier U7. One end of resistor R24 ​​is connected to terminal J3. Capacitors C7 and C8 are connected in parallel between pins 3 and 4 of terminal J3. Resistors R23 and C6 are connected in series. Resistor R22, diode D6, and diode D5 are connected in parallel to resistor R23. Capacitor C10 is connected to one of the terminals of resistors R22 and R23. Resistors R20 and R28 are connected in parallel to ground at the connection between the positive terminal of amplifier U7 and resistor R24. Amplifier U7 is responsible for receiving and amplifying the input signal. Resistors R27 and R31 are connected in series at its output to adjust the amplifier gain or act as a load resistor, ensuring signal stability during transmission. Simultaneously, signal transmission occurs through resistor R24.

[0026] The isolation unit provides signal feedback on the battery's internal resistance, while also isolating external environmental interference from the resistance feedback. The signal amplification unit detects the battery's internal resistance signal, which is then amplified by the signal detection unit. The microcontroller performs digital filtering on the acquired signal, effectively improving test accuracy while reducing the impact of the environment on the test results.

[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A battery internal resistance detection circuit, characterized in that: It includes an isolation unit, a signal amplification unit, a signal detection unit, a microcontroller, and an abnormal on / off control unit. The signal detection unit is electrically connected to both the isolation unit and the signal amplification unit. The abnormal on / off control unit is electrically connected to the isolation unit. The microcontroller is electrically connected to the isolation unit, the signal amplification unit, the signal detection unit, and the abnormal on / off control unit.

2. The battery internal resistance detection circuit according to claim 1, characterized in that: The microcontroller is configured as an STM32F chip U3. A crystal oscillator Y1 and a resistor R41 are connected in parallel between pins 2 and 3 of the STM32F chip U3. Capacitors C31 and C32 are connected to the two ends of the crystal oscillator Y1, respectively. One end of capacitor C31 and one end of capacitor C32 are grounded. A resistor R11 and a diode D4 are connected in parallel between pins 4 of the STM32F chip U3. One end of diode D4 is connected to capacitor C5. One end of capacitor C5 is connected to pin 5 of the STM32F chip U3 through capacitor C4. A capacitor C3 is connected between pins 31 and 32 of the STM32F chip U3. A resistor R9 is also connected to ground at pin 31 of the STM32F chip U3.

3. The battery internal resistance detection circuit according to claim 2, characterized in that: The isolation unit includes an optocoupler U2. Pins 1 and 3 of the optocoupler U2 are connected. Pin 2 of the optocoupler U2 is connected to pin 18 of the microcontroller via resistor R7. Pin 4 of the optocoupler U2 is connected to pin 13 of the microcontroller via resistor R10. Pin 8 of the optocoupler U2 is connected to resistor R6. One end of resistor R6 is connected to resistor R14. One end of resistor R14 is connected to amplifier U4. The output terminal of amplifier U4 is connected in series with capacitor C28 and resistor R12. One end of resistor R12 is connected to a signal detection unit. Diodes D3 and D2 are connected in parallel between the output terminal and the negative terminal of amplifier U4. One connection terminal of diodes D3 and D2 is connected to an abnormal on / off control unit. The connection terminal of resistors R14 and R6 is connected to a grounding resistor R13. Pin 5 of the optocoupler U2 is connected to the connection terminal of resistors R14 and R6.

4. The battery internal resistance detection circuit according to claim 3, characterized in that: The abnormal on / off control unit includes a relay K1. A diode D1 is connected between pins 1 and 2 of the relay K1. A transistor Q1 is connected to pin 1 of the relay K1. The base of the transistor Q1 is connected to the microcontroller through a resistor R1. A resistor R37 is connected between the base and emitter of the transistor Q1. A resistor R36 for connecting an 8V voltage is also connected to pin 2 of the relay K1. A resistor R4 is connected to pin 5 of the relay K1. A resistor R5 is connected to pin 4 of the relay K1. One end of each of the resistors R4 and R5 is connected to a signal detection unit.

5. The battery internal resistance detection circuit according to claim 4, characterized in that: The signal amplification unit includes amplifier U6 and amplifier U5. A diode D7 and a series diode D8 and resistor R32 are connected in parallel between the output terminal and the negative terminal of amplifier U6. A resistor R19 is connected to the junction of diode D8 and resistor R32. A capacitor C29, a resistor R26, and a capacitor C27 are connected in parallel to one end of resistor R19. A resistor R34 is connected to one of the junctions of capacitor C27 and resistor R26. A resistor R17 is connected to ground to the junction of resistor R19 and capacitor C27. A resistor R29, a resistor R30, and a capacitor C17 are connected in parallel between the negative terminal and the output terminal of amplifier U5. A capacitor C9 is connected to the output terminal of amplifier U5. One end of capacitor C9 is connected to the positive terminal of amplifier U6 through resistor R18. A capacitor C15 and a resistor R25 are also connected in parallel to the negative terminal of amplifier U5. The positive terminal of amplifier U5 is connected to the signal detection unit.

6. The battery internal resistance detection circuit according to claim 5, characterized in that: The signal detection unit includes an amplifier U7. The output terminal of the amplifier U7 is connected in series with resistors R27 and R31. The positive terminal of the amplifier U7 is connected to a resistor R24. One end of the resistor R24 ​​is connected to a terminal J3. Between pins 3 and 4 of the terminal J3, capacitors C7 and C8 are connected in parallel. Resistors R23 and C6 are connected in series. Resistors R22, diode D6, and diode D5 are connected in parallel to resistor R23. A capacitor C10 is connected to one of the connection terminals of resistors R22 and R23. Resistors R20 and R28 to ground are connected in parallel to the connection terminal of the amplifier U7 and resistor R24.