Lead-acid battery capacity test system

Abstract

The invention relates to the technical field of battery capacity testing, and discloses a lead-acid battery capacity testing system, which comprises a hardware platform and a software module, and is characterized in that the hardware platform comprises a single chip microcomputer, an ADC detection circuit, a nixie tube display module, a discharge control circuit, a key input module, a cooling fan and a current expansion interface; the software module runs on the single chip microcomputer, is based on an embedded operating system, and is configured to acquire a voltage signal and a current signal of the lead-acid battery in real time through the ADC detection circuit; and calculating the battery capacity by adopting a current integration method based on the current signal, and judging a discharge cut-off point based on the voltage signal. Through deep cooperation of a hardware platform and a software module, accurate and automatic testing of the capacity of the lead-acid battery is achieved, a current integration method is adopted as a core calculation principle, discharging cut-off judgment is carried out in combination with a voltage signal, and the accuracy and reliability of a capacity testing result are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery capacity testing, and in particular to a lead-acid battery capacity testing system. BACKGROUND

[0002] Current lead-acid battery capacity testing methods mostly rely on traditional discharge instruments combined with manual recording or simulation estimation based on complex electrochemical models. The former is tedious, inefficient and easily affected by subjective factors, while the latter requires the establishment of an accurate battery model and relies on a large amount of pre-test data, making it difficult to apply to on-site rapid assessment and maintenance scenarios.

[0003] In addition, some methods also require destructive disassembly of the battery to analyze the internal structure, which not only complicates the operation, but also limits its widespread application in finished battery testing. SUMMARY

[0004] The present application provides a lead-acid battery capacity testing system to solve the existing technical problems, solving the problem of relying on complex models or destructive disassembly in traditional methods.

[0005] To solve the above technical problems, according to one aspect of the present application, more specifically, a lead-acid battery capacity testing system, comprising a hardware platform and a software module, the hardware platform comprising a single-chip microcomputer, an ADC detection circuit, a digital tube display module, a discharge control circuit, a key input module, a cooling fan and a current expansion interface; The software module runs on the single-chip microcomputer and is based on an embedded operating system, configured to: a) Real-time acquisition of voltage and current signals of the lead-acid battery through the ADC detection circuit; b) Calculation of battery capacity based on the current signal using the current integration method, and determination of the discharge cutoff point based on the voltage signal; c) Control of the discharge control circuit to perform discharge testing, and real-time display of battery capacity, voltage and current values through the digital tube display module; d) Including a safety protection submodule for stopping discharge and triggering audible and visual alarms when overvoltage, overheating or short circuit is detected; e) Supporting multi-machine parallel testing and data export functions.

[0006] Further, the software module calculates the battery capacity using the current integration method, with the calculation formula being:

[0007] wherein, represents the battery capacity, with the unit being ampere-hour; is the current value of the kth sampling point, with the unit being ampere; represents the sampling interval, with the unit being hour; N is the number of sampling points.

[0008] Further, the current value The conversion formula includes a calibration factor, which is:

[0009] Wherein, is the ADC raw sampling value of the current channel; is the reference voltage, unit: volt; is the shunt resistance value, unit: ohm; n is the ADC resolution, unit: bit; is the calibration offset.

[0010] Further, the overvoltage protection of the safety protection submodule is triggered when the real-time battery voltage exceeds the settable voltage threshold, wherein the default value of the voltage threshold is 14.5V. The overvoltage protection trigger condition of the safety protection submodule is:

[0011] In the above formula, represents the real-time battery voltage; represents the settable voltage threshold, the default value is 14.5V.

[0012] Further, the overheat protection of the safety protection submodule is triggered when the real-time temperature of the system exceeds the maximum allowable temperature, wherein the default value of the maximum allowable temperature is 60℃. The overheat protection trigger condition of the safety protection submodule is:

[0013] In the above formula, represents the real-time temperature of the system; represents the maximum allowable temperature, the default value is 60℃.

[0014] Further, the lead-acid battery capacity test system further comprises a capacity estimation optimization module for dynamically adjusting the capacity calculation according to the battery voltage drop curve, wherein the adjusted capacity value is the original calculated capacity minus a correction amount, and the correction amount is proportional to the proportion of the difference between the rated voltage of the battery and the real-time voltage to the rated voltage, and the proportion coefficient is the decay coefficient, wherein the default value of the decay coefficient is 0.05, and the default value of the rated voltage of the battery is 12V. The capacity estimation optimization module is used to dynamically adjust the capacity calculation according to the battery voltage drop curve, and the optimization formula is:

[0015] In the above formula, represents the adjusted capacity value; C represents the original calculated capacity; represents the decay coefficient (default value 0.05); represents the rated voltage of the battery (12V); represents the real-time voltage.

[0016] Further, the number tube display module adopts a dynamic scanning mode, and the display format comprises: Capacity display: 5-digit number tube, the first 2 digits in red represent the integer part, and the last 3 digits in green represent the decimal part; Voltage display: 4-digit number tube, the first 2 digits in red represent the integer part, and the last 2 digits in green represent the decimal part; Current display: 4-digit number tube, the first digit in red represents the integer part, and the last 3 digits in green represent the decimal part.

[0017] Further, the lead-acid battery capacity test system supports online upgrading of firmware, receives update data through serial communication, and adopts a double backup storage mechanism to prevent upgrade failure.

[0018] Further, the discharge control circuit adopts a MOSFET switching device, the driving signal is modulated by a single-chip microcomputer through PWM, and the discharge power is dynamically adjusted by multiplying the discharge current by the real-time battery voltage and then by a discharge efficiency coefficient, wherein the default value of the discharge efficiency coefficient is 0.95.

[0019] Further, the software module further comprises a self-diagnosis function, which periodically checks the ADC sampling accuracy and the discharge circuit state, and the checking formula is:

[0020] wherein Error represents a measurement error, and when Error exceeds 5%, a system calibration prompt is triggered; represents a measured voltage value, which is a voltage value actually sampled and converted by the ADC detection circuit in the lead-acid battery capacity test system; represents a standard voltage value, which is a known, high-precision, and reference voltage value. In the system self-diagnosis process, a known, stable standard voltage signal is usually inputted for verifying the measurement accuracy of the system itself.

[0021] The lead-acid battery capacity test system provided by the application has the following effects compared with the prior art: 1. The application realizes accurate and automatic testing of the capacity of a lead-acid battery through deep cooperation between a hardware platform and a software module, adopts a current integration method as a core calculation principle, and combines a voltage signal for discharge cutoff judgment, thereby ensuring the accuracy and reliability of the capacity test result. Real-time data acquisition and processing under an embedded operating system make the testing process efficient and responsive, effectively overcoming the limitations of traditional methods that rely on complex models or destructive disassembly, and providing a simple-to-operate and reliable result on-site evaluation tool for the maintenance industry.

[0022] 2、The application integrates multiple security protection mechanisms, including overvoltage, overheat and short circuit protection, and is assisted by sound and light alarm prompt. When the system detects that the real-time battery voltage exceeds the preset threshold or the temperature exceeds the safety limit, the discharge circuit can be immediately cut off, thereby effectively preventing safety hazards such as battery overdischarge and system overheating, ensuring the safety of the test process and prolonging the service life of the equipment and the battery.

[0023] 3、The application has data power failure saving and firmware online upgrade functions. The single-chip microcomputer internally stores key test data in EEPROM, which can be recovered even if power failure occurs, ensuring the integrity of the data and the continuity of the test. The online upgrade scheme with double backup storage mechanism ensures the safety and reliability of system firmware update, avoids system paralysis caused by upgrade failure, and improves the maintainability of the equipment and the convenience of technical iteration.

[0024] 4、The application designs an intuitive and standardized digital tube display scheme, which uses digital tubes of different bit numbers and colors to display capacity, voltage and current, so that users can easily read key parameters. Combined with clear key functions and prompt sound feedback, the system is friendly to human-computer interaction, reduces the operation threshold, and enables non-professionals to easily complete battery performance testing and evaluation.

[0025] 5、The application supports multi-machine parallel testing through a standard current expansion port and has data export capability. This feature enables the system to flexibly respond to battery testing needs of different capacity specifications, expanding the application range. At the same time, the built-in self-diagnosis function of the system can periodically check the ADC sampling accuracy to ensure the accuracy of long-term testing, thereby providing users with a stable, reliable and expandable professional testing solution. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a system structure diagram of the application; Figure 2 is a panel component diagram of the application. DETAILED DESCRIPTION

[0027] To make the technical scheme of the application clearer, the application will be further described in detail below in combination with the drawings and specific embodiments.

[0028] The lead-acid battery capacity testing system provided in this embodiment is characterized by software and hardware collaborative design, which realizes precise, safe and automatic testing of lead-acid battery capacity.

[0029] I. Specific implementation of hardware platform Reference Figure 1 (System structure diagram), the hardware platform (such as Figure 2The high-performance STC32G series single-chip microcomputer is used as the main control chip. The single-chip microcomputer is responsible for signal processing, logic control and data operation of the whole system.

[0030] 1) Signal acquisition unit: The ADC detection circuit is responsible for acquiring the voltage and current signals of the battery.

[0031] Voltage sampling: The high voltage of the battery (such as 12V) is attenuated by a voltage dividing resistor to a voltage range (such as 0-3.3V) acceptable to the ADC pin (such as P1.5) of the single-chip microcomputer.

[0032] Current sampling: A precision shunt resistor (for example ) is connected in series in the discharge circuit to convert the discharge current into a small voltage signal. After being amplified by an operational amplifier, the signal is sent to another ADC pin (such as P1.1) of the single-chip microcomputer for sampling. In the source code, the ADC_CONTR register is switched between 0x81 (P1.1, current) and 0x85 (P1.5, voltage) to acquire the current and voltage signals in time-sharing mode.

[0033] 2) Discharge control unit: The discharge control circuit uses MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) as the power switching device. The single-chip microcomputer outputs high / low level through I / O port (such as P3.6, corresponding to QDK in the source code) to directly or through a driver chip control the conduction and cutoff of MOSFET, thereby connecting or disconnecting the discharge resistor circuit parallel to the battery, realizing the control of the discharge process. In the source code, QDK=1 means starting the discharge.

[0034] 3) Human-computer interaction unit: Display module: 5-bit integrated common anode digital tube is used. P2 port of the single-chip microcomputer is used as segment selection signal, outputting word module data (defined in LED7D array). Five bit selection signals (H1-H5) are controlled by P0.5, P4.1, P0.6, P0.7 and P1.0 of the single-chip microcomputer, and the display is realized by dynamic scanning mode (in the while (1) loop of main function, each bit is lit in turn according to the value of SMSX%5). The display format strictly follows the capacity display: 5-bit digital tube, the first 2 bits in red represent the integer part, and the last 3 bits in green represent the decimal part; voltage display: 4-bit digital tube, the first 2 bits in red represent the integer part, and the last 2 bits in green represent the decimal part; current display: 4-bit digital tube, the first 1 bit in red represents the integer part, and the last 3 bits in green represent the decimal part.

[0035] For example, if the capacity display is 5 bits, the first 2 bits (H1, H2) in red display the integer part (ampere-hour), and the last 3 bits (H3, H4, H5) in green display the decimal part (milliampere-hour).

[0036] Key input module: three function keys (QL1 - clear, QD2 - start, DY3 - voltage / charge switch) are connected to the P1.3, P5.4, P4.0 pins of the single-chip microcomputer, and are configured as pull-up inputs. The program detects the change of pin level (if (!QL1)...) to identify the key operation, and cooperates with the buzzer (FMQ, P3.4) to issue prompt sounds of different lengths, providing clear user feedback.

[0037] 4), auxiliary unit: Cooling fan: controlled by the I / O port of the single-chip microcomputer, started during the discharge process to forcibly cool the discharge resistor and prevent the system from overheating.

[0038] Current expansion port: provides a standard interface to allow external connection of a larger power expansion discharge device to test higher capacity batteries, and coordinates the synchronous work of multiple devices through the main control board to achieve multi-machine parallel testing.

[0039] Data storage: uses the EEPROM integrated in the single-chip microcomputer (operated through functions in STC32G_EEPROM.h) to periodically store the accumulated battery capacity data (variable AH) after being decomposed into multiple bytes into the specified address (such as 0x0010). The system automatically reads these data when powered on, achieving power failure saving of test data.

[0040] II. Specific implementation of software modules and algorithm realization The software modules run on an embedded operating system based on UCOSII, and complete various tasks through cooperation of interrupts and main loops.

[0041] 1), implementation of capacity calculation (current integration method): Capacity calculation is the core. In the main loop, the system executes the following steps at a fixed time interval (SMSX variable increases by about 1ms, and current sampling is performed at 400ms): Step 1, current value acquisition: call the HandleADC() function to read the ADC raw value IY of the current channel.

[0042] Step 2, current value calibration and conversion: scale and calibrate the original ADC value through the empirical formula I = ((IY*264000) / 1) + 1800000; convert the ADC value to the actual current value (unit: microampere or other internal unit). The coefficient (264000) and offset (1800000) are obtained through actual measurement calibration based on the known reference voltage (Vref), shunt resistor (Rshunt), and ADC resolution (n = 12 bits).

[0043] ​​Step 3: The ampere-hour integration is performed using the statement AH = AH + (I / 3240); Here, (I / 3240) is approximately... ,in It is fixed in coefficient 3240. The system continuously accumulates to obtain the battery capacity in milliampere-hours (mAh) or ampere-hours (Ah).

[0044] 2) Implementation of the capacity estimation optimization module: For example, the capacity estimation and optimization module dynamically adjusts the capacity calculation based on the battery voltage drop curve. To more accurately reflect the battery's capacity during actual discharge, the system introduces dynamic adjustment. Based on the original capacity C, when the battery voltage... As the value decreases, a correction amount is used to adjust the final displayed capacity value. The program monitors the battery voltage (V) in real time. Before displaying the capacity, it calls an optimization algorithm:

[0045] In the above formula, C represents the adjusted capacity value; C represents the original calculated capacity. It is 12V (rated voltage). t represents the real-time measured voltage. The default value for the (attenuation coefficient) is 0.05. The physical meaning of this formula is: the greater the voltage drop, the greater the internal resistance of the battery or the lower the utilization rate of the active material. The actual release capacity will be reduced relative to the ideal integral value, hence the reduction.

[0046] 3) Implementation of the security protection submodule: In overvoltage protection, the overvoltage protection trigger condition of the safety protection submodule is:

[0047] In the above formula, Indicates real-time battery voltage; This indicates the settable voltage threshold, with a default value of 14.5V. The program determines the real-time voltage V (an internally calculated value that needs to be converted to the actual voltage value) at the voltage sampling time (SMSX==800). If V exceeds the set threshold (default 14.5V), QDK=0 is immediately executed, the discharge MOSFET is turned off, and a continuous alarm sound is emitted via a buzzer.

[0048] In overheat protection, the overheat protection trigger condition of the safety protection submodule is as follows: ; In the above formula, This indicates the system's real-time temperature. This indicates the maximum permissible temperature; the default value is 60℃. The system can obtain the real-time system temperature via a temperature sensor (which can be connected to the ADC channel). In the main loop, if QDK=0 and an alarm is triggered.

[0049] In hardware, a fast fuse is connected in series with the discharge circuit; in software, the current value is continuously monitored, and if it is found to be far beyond the normal range, the discharge circuit is immediately cut off.

[0050] 4) Implementation of self-diagnosis function: To ensure the accuracy of long-term measurement of the system, the software has a self-diagnosis process. The implementation process is as follows: Periodically (e.g. every 24 hours) or when the user triggers calibration, the system will control the internal relay (not shown in the figure) to connect a known, high-precision standard voltage source V_standard (e.g. 5.000V) to the ADC sampling channel.

[0051] Error calculation, the system measures this standard voltage, and gets . Then calculate the measurement error: Where, if the calculated Error is greater than 5%, a specific error code (e.g. "Err-5") is displayed on the digital tube, and the user is prompted to perform professional calibration. This process effectively verifies the ADC sampling accuracy, ensuring the reliability of the entire test system.

[0052] 5) Firmware online upgrade: The system communicates with the host computer through serial port 1 (UART1, P3.0 and P3.1). Using the built-in IAP (In-Application Programming) function, the new firmware program data received through the serial port can be written to the specified Flash sector. A dual backup storage mechanism is adopted, i.e. there are two independent program storage areas, when one area fails to upgrade, the system can automatically switch back to the old version program of the other area, ensuring that the system will not be "bricked" due to unexpected upgrade.

[0053] Without complex full discharge curve modeling and a large number of pre-tests, the battery capacity can be quickly and directly obtained through real-time current integration and optimized voltage adjustment algorithm, the test efficiency is higher, and it is suitable for on-site rapid evaluation. And it is completely non-destructive test, without disassembling the battery, without damaging the battery itself, safe and simple operation. And the focus is on the overall performance (capacity) of the finished battery, rather than the performance of single lead powder material, the application level is closer to the actual maintenance and evaluation scene.

[0054] ​The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A lead-acid battery capacity testing system, comprising a hardware platform and software modules, characterized in that: The hardware platform includes a microcontroller, an ADC detection circuit, a digital tube display module, a discharge control circuit, a key input module, a cooling fan, and a current expansion interface. The software module runs on the microcontroller, is based on an embedded operating system, and is configured as follows: a) The voltage and current signals of the lead-acid battery are acquired in real time through the ADC detection circuit; b) Calculate the battery capacity using the current integration method based on the current signal, and determine the discharge cutoff point based on the voltage signal; c) Control the discharge control circuit to perform a discharge test, and display the battery capacity, voltage and current values ​​in real time through the digital tube display module; d) Includes a safety protection submodule, used to stop discharging and trigger an audible and visual alarm when overvoltage, overheating or short circuit is detected; e) Supports multi-machine parallel testing and data export functions.

2. The lead-acid battery capacity testing system according to claim 1, characterized in that: The software module calculates battery capacity using the current integral method, and the calculation formula is as follows: ； in, Indicates battery capacity, measured in ampere-hours; The value is the current at the k-th sampling point, in amperes. The sampling interval is represented in hours; N is the number of sampling points.

3. The lead-acid battery capacity testing system according to claim 2, characterized in that: The current value The value is obtained by converting ADC sampled values. The conversion formula includes a calibration factor, specifically: ； in, This represents the original sampled value of the ADC in the current channel; Reference voltage, in volts; n is the shunt resistor value in ohms; n is the ADC resolution in bits. To calibrate the offset.

4. The lead-acid battery capacity testing system according to claim 1, characterized in that: The overvoltage protection of the safety protection submodule is triggered when the real-time battery voltage exceeds a settable voltage threshold, wherein the default value of the voltage threshold is 14.5V.

5. The lead-acid battery capacity testing system according to claim 1, characterized in that: The overheat protection of the safety protection submodule is triggered when the real-time system temperature exceeds the maximum allowable temperature, wherein the default value of the maximum allowable temperature is 60°C.

6. The lead-acid battery capacity testing system according to claim 1, characterized in that: The lead-acid battery capacity testing system also includes a capacity estimation and optimization module, which is used to dynamically adjust the capacity calculation based on the battery voltage drop curve. The adjusted capacity value is the original calculated capacity minus a correction amount. This correction amount is proportional to the ratio of the difference between the battery's rated voltage and real-time voltage to the rated voltage. The proportionality coefficient is the attenuation coefficient, and the default value of the attenuation coefficient is 0.

05. The default value of the battery's rated voltage is 12V.

7. The lead-acid battery capacity testing system according to claim 1, characterized in that: The digital tube display module adopts a dynamic scanning method, and the display format includes: Capacity display: 5-digit LED display, the first 2 digits are red to represent the integer part, and the last 3 digits are green to represent the decimal part; Voltage display: 4-digit LED display, the first 2 digits are red to represent the integer part, and the last 2 digits are green to represent the decimal part; Current display: 4-digit LED display, the first digit is red to represent the integer part, and the last 3 digits are green to represent the decimal part.

8. The lead-acid battery capacity testing system according to claim 1, characterized in that: The aforementioned lead-acid battery capacity testing system supports online firmware upgrades, receives updated data via serial communication, and employs a dual backup storage mechanism to prevent upgrade failures.

9. The lead-acid battery capacity testing system according to claim 1, characterized in that: The discharge control circuit uses MOSFET switching devices, and the drive signal is modulated by a microcontroller via PWM. The discharge power is dynamically adjusted by multiplying the discharge current by the real-time battery voltage and then by the discharge efficiency coefficient, wherein the default value of the discharge efficiency coefficient is 0.

95.

10. The lead-acid battery capacity testing system according to claim 1, characterized in that: The software module also includes a self-diagnostic function, which periodically verifies the ADC sampling accuracy and discharge circuit status. The verification formula is: ； Here, Error represents measurement error. When Error exceeds 5%, a system calibration prompt is triggered. Indicates the measured voltage value; This indicates the standard voltage value.

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