CN204807679U - Portable battery performance measurement appearance - Google Patents

Abstract

The portable battery performance measuring instrument of the utility model mainly includes a voltage and current detection part and a single-chip microcomputer system, an output display and an alarm part. It is based on the STC12C5A60S2 single-chip microcomputer, and the voltage is detected and collected through the self-contained AD of the single-chip microcomputer, and the ACS712ELC-20A is used as the current The collector detects the battery capacity. Its working process is that the single-chip microcomputer detects the working current, working voltage and open circuit voltage of the battery, calculates the remaining capacity according to a certain algorithm, and sends it to the LCD display for display. When the measurement is completed, the single-chip microcomputer sends a signal to drive the buzzer, and the buzzer sounds. This system is simple in design and low in cost, and is suitable for measuring and detecting the most commonly used and intuitive open circuit voltage, internal resistance, and capacity parameters.

Description

A portable battery performance measuring instrument

Technical field:

The utility model belongs to the field of battery measuring circuit design and specifically designs a battery performance measuring instrument based on STC12C5A60S2 single-chip computer program control.

Background technique:

With the development of the times, batteries have become an important consumable in daily life. The rapid development of my country's communication, power electronics and other related industries has made people pay more and more attention to the utilization rate and maintenance of lithium-ion batteries and other batteries, and the market demand for battery performance testing has also increased. At present, the demand for batteries of various electronic products continues to increase, and the quality requirements for batteries are higher. Battery detection and maintenance are of great significance to personal safety and actual use requirements. The portable battery performance detection system designed in this paper measures the actual capacity of the battery through the integration of current to time, and collects and measures the voltage through the AD of the single-chip microcomputer itself. By directly observing important parameters of battery voltage, capacity and internal resistance through the display screen, inferior batteries can be effectively identified, thereby reducing potential threats to electronic equipment and people. The system is simple in design and low in cost, and is suitable for industrial and personal use.

Invention content:

The purpose of this utility model is to overcome the shortcomings of high cost and large volume of the existing battery measuring instruments, and provide a new type of portable battery measuring instrument based on a single-chip microcomputer. The circuit is easy to make, reliable, good in stability, high in control precision and strong in practicability .

For realizing above technical purpose, the scheme that the utility model adopts is:

A portable battery performance measuring instrument, the single-chip microcomputer adopts the STC12C5A60S2/AD/PWM series single-chip microcomputer of the STC series; the described current detection module adopts ACS712ELC-20A as the current collector; There are 2 gears for lithium batteries and dry batteries, and the value of the resistor divider is switched by a relay; the constant current circuit is composed of a triode 2SC2500 and 3 resistors, and the discharge current is determined by the ratio and resistance of the resistors.

Its overall structure is characterized in that it is composed of a current detection module, a voltage detection module, a battery gear automatic selection module, a battery rapid discharge gear and a constant current discharge gear. The voltage is detected and collected through the built-in AD of the single-chip microcomputer, and the battery capacity is detected with the ACS712ELC-20A as the current collector. STC12C5A60S2/AD/PWM series single-chip microcomputer is a single-clock/machine cycle (1T) single-chip microcomputer produced by STC. It is a new generation of 8051 single-chip microcomputer with high speed, low power consumption and super anti-interference. The instruction code is fully compatible with traditional 8051, but the speed is fast. 8-12 times. Internally integrated MAX810 dedicated reset circuit, 2-way PWM, 8-way high-speed 10-bit A/D conversion (250K/S), for motor control and strong interference occasions. The voltage measurement module uses the high-speed AD acquisition port of the single-chip microcomputer to collect; the battery gear automatic selection module, through 4 resistors, forms two gears of lithium battery and dry battery, and judges through AD acquisition and a relay to automatically switch the lithium battery gear and dry battery stalls. The fast discharge gear and the constant current gear are switched by a relay. The constant current is a battery constant current discharge circuit composed of a triode 2SC2500 and 3 resistors. The discharge current is determined by the ratio and resistance of the resistors.

The beneficial effects of the utility model are:

(1) Use the 8-way high-speed 10-bit A/D conversion (250K/S) of the STC12C5A60S2 single-chip microcomputer for voltage acquisition, with fast speed and high precision, and the precision can reach 1μV.

(2) Use ACS712ELC-20A to measure current for the current collector. The response time between input and output is 5μs. It can measure plus or minus 20A current. The corresponding analog output is 100mV/A, and the current measurement is more accurate and high-speed.

(3) The single-chip microcomputer has high speed, low power consumption, super anti-interference ability, low cost, convenient and reliable circuit production, high measurement accuracy and strong practicability, and can be used in experimental teaching, engineering practice and daily life.

Description of drawings

Fig. 1 is the hardware principle block diagram of the utility model

Fig. 2 is the typical application of ACS712 of the present utility model

Fig. 3 is each module measuring circuit of the present utility model

Fig. 4 is the main program flow diagram of the utility model

Detailed ways

The utility model is described in further detail below in conjunction with accompanying drawing and specific embodiment.

The system hardware block diagram is shown in Figure 1, mainly including the voltage and current detection part and the single-chip microcomputer system, output display and alarm part. The main working process is that the single-chip microcomputer detects the working current, working voltage and open circuit voltage of the battery, calculates the remaining capacity according to a certain algorithm, and sends it to the LCD display for display. When the measurement is completed, the single-chip microcomputer sends a signal to drive the buzzer, and the buzzer sounds.

This system uses the current time integral method to measure the battery capacity, then processes the data, and finally transmits it to LED1602 in real time, and selects the function and displays the test results through the 1602LCD display.

The voltage measurement of this system is to use the 8-way high-speed 10-bit A/D conversion (250K/S) of the STC12C5A60S2 microcontroller for voltage acquisition. The detection speed is fast and the accuracy can reach 1μV.

This system uses the Allegro Hall current sensor for current measurement, its model is ACS712ELC-20A. A typical application is shown in Figure 2. The accuracy of the full temperature range of ACS712ELC-20A is ±1.5%, and the accuracy characteristics are better at 25-85°C. The response time between input and output is 5μs, and it can measure ±20A range Current, which corresponds to an analog output of 100mV/A.

The measurement circuit of each module is shown in Figure 3. VT ₁ , R ₁ , R ₄ , R ₅ etc. constitute the battery constant current discharge circuit. The discharge current is determined by the ratio of R ₅ , R ₄ and the resistance value of R _1. The discharge current is set at 200mA . Select one of the 8-channel ADs of the STC12C5A60S2 single-chip microcomputer, P1.0, as the voltage acquisition port of the battery. The relay K ₁ is controlled by P2.1 to perform discharge switching. When P2.1 outputs a low level, the relay acts and enters a rapid discharge state. When P2.1 outputs a high level, the relay resets, and at this time P2.3 is low. Normally, the triode is not conducting and is in a high-impedance state, and the battery is approximately in an open circuit state. When P2.3 is high, the triode is conducting and the battery is in a constant current state.

Automatic gear switching, this module judges the type of the battery to be tested through the open circuit voltage measured in the first step, and then controls the relay through P2.2 to switch gears to set the cut-off voltage. At this time, the comparator LM358 outputs a low level and sends it to P2.4. After the microcontroller recognizes it, it will alarm, and then the measurement process ends, and the result is transmitted to the LCD screen in real time.

For the measurement of internal resistance, the response time between the input and output of ACS712ELC-20A chip is 5μs. By controlling the relay K ₁ , select the fast discharge gear, and perform 5ms point collection to collect the current and voltage values at the moment. The calculation is carried out through the calculation formula of _internal resistance: Rin = (V ₀ -V)/I. Collect once every 200ms, collect 4 times and calculate the average value. Finally, the internal resistance value of the battery is obtained and sent to the LCD for display.

The program is written in C language, and the program is composed of the main program, the timer interrupt service subroutine, and the delay subroutine. The main program flow diagram is shown in Figure 4.

The VCC in this embodiment is powered by 5V, the precision control can reach within 1μV, and the current in the range of ±20A can be measured. The system is simple in design and low in cost, and can be applied in circuit design, practical teaching and daily life.

Claims (5)

1. A portable battery performance measuring instrument, the overall structure is characterized in that it includes: a current detection module, a voltage detection module, a battery gear automatic selection module, a battery rapid discharge gear and a constant current discharge gear; wherein the current detection The module uses ACS712ELC-20A as the current collector, which is realized through program assistance; the voltage measurement module uses the high-speed AD acquisition port of the single-chip microcomputer to collect; the battery gear automatic selection module is divided by 4 resistors to form a lithium battery and a dry battery. The gears are judged by AD acquisition and a relay automatically switches between the lithium battery gear and the dry battery gear; the fast discharge gear and the constant current gear are switched by a relay, and the constant current is composed of a triode 2SC2500 and 3 resistors Battery constant current discharge circuit, the discharge current is determined by the ratio and resistance of the resistors. 2. A portable battery performance measuring instrument according to claim 1, characterized in that: said single-chip microcomputer adopts STC12C5A60S2/AD/PWM series single-chip microcomputer of STC series. 3. A portable battery performance measuring instrument according to claim 1, characterized in that: said current detection module uses ACS712ELC-20A as a current collector. 4. A portable battery performance measuring instrument according to claim 1, characterized in that: said battery gear automatic switching circuit is divided into two gears of lithium battery and dry battery, and the value of the resistance divider is switched by a relay . 5. A portable battery performance measuring instrument according to claim 1, characterized in that: said constant current circuit is composed of a triode 2SC2500 and 3 resistors, and the discharge current is determined by the ratio and resistance value of the resistors.