Battery testing device with passive temperature compensation and calibration method

Abstract

The invention discloses a battery testing device with passive temperature compensation and a calibration method. The system solves the problem that the environment temperature change affects the inconsistency of the actually measured current and the display current in the existing battery test system, and finally causes the inaccurate test of the battery capacity in the high and low temperature environment. The battery test system comprises a battery test system, a battery test system calibration tool, a temperature sensor, a high and low temperature test box, a six-bit and half-table, a battery, a communication line and a computer, and is mainly used for battery tests at different environment temperatures.

Description

Technical Field

[0001] The present invention relates to the field of battery testing, and particularly to a battery testing system with passive temperature compensation and a calibration method. Background Art

[0002] During the battery testing process, different ambient temperatures and different charge and discharge currents produce different temperature drifts on the sampling resistor and different zero-point temperature drifts on the sampling circuit.

[0003] For a battery testing system, regardless of the battery testing temperature, battery testing current, and current testing voltage, the display values corresponding to different voltages are constant. This is because the display values are derived from the converted voltage amplitude. Since the conditioning circuit of the detection circuit is fixed after design, its gain is also fixed.

[0004] Temperature has a certain influence on the zero-point temperature drift of the sampling circuit, and temperature has a greater influence on the temperature drift of the sampling resistor. For the display voltage value, the display voltage value is equal to the measured value multiplied by the voltage gain, plus the converted value of the zero-point temperature drift; regardless of how the temperature changes, as long as the actual voltage remains unchanged and the change in the zero-point temperature drift is small or even negligible, the converted values corresponding to different voltages are basically the same. Therefore, it is often seen that the display voltage value remains basically unchanged with high precision when the test temperature changes; for the display current value, the display current value is equal to the sampling resistor value multiplied by the measured current value, then multiplied by the current gain, plus the converted value of the zero-point temperature drift; regardless of how the temperature changes, as long as the product of the measured current and the sampling resistor remains unchanged and the change in the zero-point temperature drift is small or even negligible, the converted values corresponding to different currents are basically the same. Therefore, it is often seen that the display current value remains basically unchanged with high precision when the test temperature changes; for the measured voltage value, the measured voltage value is equal to the measured value multiplied by the voltage gain, plus the converted value of the zero-point temperature drift; regardless of how the temperature changes, as long as the actual voltage remains unchanged and the change in the zero-point temperature drift is small, the converted values corresponding to different voltages are basically the same. Therefore, it is often seen that the measured voltage value of the test temperature change maintains high precision, and the tiny change can basically be ignored; for the measured current value, the measured current value is equal to the sampling resistor value multiplied by the measured current value, then multiplied by the current gain, plus the converted value of the zero-point temperature drift, and then after conversion, it is equal to the measured value of the 6 1 / 2-digit table; regardless of how the temperature changes, although the product of the measured current and the sampling resistor remains unchanged, but affected by temperature, the resistance value will change with the temperature drift, thus causing a change in the measured current. Therefore, it is often seen that the measured current of the test temperature change is larger or smaller than the actual current; Therefore, as the ambient temperature of the electrical measurement test system varies, the measured value of the battery current will also be affected to varying degrees, and the accuracy of the electrical measurement test system will also change accordingly. This will seriously affect the accurate detection of current, capacity, internal resistance, etc. by the battery testing system, thereby affecting the results of battery formation, grading, scientific experiments, and research. Summary of the Invention

[0005] Aiming at the deficiencies existing in the prior art, the present invention provides a battery testing device with passive temperature compensation and a calibration method, which solves the defect that the change of ambient temperature in the existing battery testing system affects the inconsistency between the measured current and the displayed current, and finally leads to inaccurate measurement of the battery capacity in high and low temperature environments, so as to achieve the consistency of the measured voltage value, the measured current value and the calibration value under different temperature environments, thereby reducing the influence of different temperature changes on the measured voltage value and the measured current value.

[0006] To achieve the above object, the present invention provides the following technical solutions: A battery testing device with passive temperature compensation includes a battery testing system for providing a testing platform, which is internally provided with a temperature sensor, a voltage and current setting mechanism, a voltage and current conditioning, conversion and detection mechanism, and a switch tube driving mechanism; a calibration tooling for the battery testing system for building a calibration platform, connecting the battery testing system and a standard device to achieve calibration under different temperatures / powers; a high and low temperature test chamber for simulating different temperature environments to provide test conditions; the calibration tooling for the battery testing system is also connected with a resistor, a battery and a switch. The resistor is used to provide a calibration object and to simulate different power loads, the battery is used to provide a test object, and the switch is used for real-time communication. The above temperature sensor is used to detect the temperature value of the battery testing system working in different working environments, and is used as a judgment condition for voltage and current compensation under different temperature environments.

[0007] Further preferably, the standard device is a 6 1 / 2 digit bench meter: having high-precision measurement ability, used to measure the measured current value and the measured voltage value during battery testing or calibration, and providing a reference standard for the displayed value and the measured value of the battery voltage and current; In the present invention, the difference between the displayed current of the battery testing system at different temperatures and the measured current of the 6 1 / 2 digit bench meter is large. The calibration system composed of the calibration tooling, the 6 1 / 2 digit bench meter and the battery can calibrate the current displayed value and the current measured value under different temperature environments; and the difference between the displayed current of the battery testing system at different powers and the measured current of the 6 1 / 2 digit bench meter is large. The calibration system composed of the calibration tooling, the 6 1 / 2 digit bench meter and the battery can calibrate the current displayed value and the current measured value under different powers.

[0008] Further preferably, the calibration tooling: provides a platform for connection and calibration, which can ensure normal switching under different channels, different modes, different temperatures and power conditions, and realize stable connection and calibration operations between the battery test system and other devices. 6 1 / 2-digit bench meter: As a high-precision measurement device, it can provide accurate measured current values, serving as a reference standard for calibration. It can accurately measure the actual current of the battery at different temperatures and powers, and its measurement accuracy can reach the order of one in a million, providing a reliable basis for calibration. Battery: As the test object, it is tested at different temperatures and powers. During the test, its charge and discharge current data are collected, used to compare the display current and the measured current, and then determine the calibration coefficient. The calibration tooling mentioned in the present invention has the same meaning as the calibration tooling of the battery test system.

[0009] Specific calibration process: Temperature environment calibration: Place the battery test system in a high and low temperature test chamber, and set different temperature points, such as T1, T2, T3......Tn, etc. The 6 1 / 2-digit bench meter measures the actual current value of the battery at different temperatures in real time, and at the same time the battery test system records the display current value. The calibration tooling compares and analyzes the two sets of data, and calculates the calibration coefficients at different temperatures (such as parameters like slope and intercept). Store the calibration coefficients in the battery test system. When actually testing, the system calls the corresponding calibration coefficients according to the temperature detected by the temperature sensor to correct the display current value and achieve calibration.

[0010] Power environment calibration: Set different charge and discharge powers of the battery, such as low power, medium power, high power and other working conditions. Similarly, the 6 1 / 2-digit bench meter measures the actual current, and the battery test system records the display current. The calibration tooling analyzes the difference between the two, and calculates the calibration coefficients for different powers. Store the calibration coefficients. When actually testing batteries with different powers, the system calls the corresponding coefficients to calibrate the display current value to ensure the consistency between the display current and the measured current.

[0011] In the present invention, when calibrating the battery test system, the calibration coefficients of the display and measured voltage values and current values under different temperature and power environments are calibrated and stored in segments. When the battery test system is testing, it calls the calibration coefficients of the display and measured voltage values and current values under different temperature and power environments in segments; further, the battery test system adapts to different temperature and power environments of battery testing by changing the voltage values and current values under different temperature and power environments.

[0012] Furthermore, the present invention adopts the principle of segmented calibration and storage, specifically: temperature influence, temperature changes will cause temperature drift of the sampling resistor in the battery test system, and the circuit will also have zero-point temperature drift. At different temperatures, the measured values of voltage and current have different deviations from the displayed values. For example, at low temperatures, the resistance value changes little, and the deviation is relatively small; at high and low temperatures, the resistance value changes greatly, and the deviation is also large. Therefore, it is necessary to segment by temperature, and measure the displayed voltage and current values of the battery test system in different temperature segments and the voltage and current values measured by the 6-digit semi-table meter respectively. By comparing these values, mathematical methods are used to calculate the calibration coefficient corresponding to each temperature segment, such as parameters such as the slope and intercept in the linear relationship, and then these calibration coefficients are stored. Power influence, the working state of the battery test system is different under different powers. At high power, the current is large, and the circuit load change has a great impact on the measurement; at low power, the impact is relatively small. Therefore, for different power conditions, the displayed value and the measured value are also measured, and the calibration coefficient of the corresponding power segment is calculated and stored.

[0013] Segmented calibration coefficient call, when the battery test system is actually tested, the temperature sensor will detect the ambient temperature in real time, and the system will determine which preset temperature segment the current temperature is in. At the same time, the current power segment is determined based on the battery charge and discharge settings. Then the system automatically calls the calibration coefficients of the corresponding temperature segment and power segment from the storage unit. For example, if the current temperature is 25℃, which is in the 25℃±0.5℃ temperature segment, the calibration coefficients of the temperature segment and the corresponding power segment are called. The calibration coefficients are applied to the currently measured displayed voltage and current values, and the displayed values are corrected through mathematical operations to make the corrected displayed values closer to the actual measured values.

[0014] Change the voltage and current values to adapt to the environment, and adjust the voltage value: through the coordinated work of the voltage and current setting mechanism and the switch tube drive mechanism. For example, in high and low temperature environments, according to the calibration coefficient and the current measurement deviation, the system controls the switch tube drive mechanism to adjust the driving voltage amplitude and change the voltage value in the circuit. Or adjust the voltage feedback value, and use the feedback mechanism to make the voltage value reach a level that adapts to accurate measurement in high and low temperature environments. Current value adjustment: also with the help of the switch tube drive mechanism. Taking different power environments as an example, when in high power conditions, according to the calibration coefficient, it is found that the displayed current and the measured current have a large deviation. The system controls the switch tube drive mechanism to adjust the PWM pulse width and change the current value in the circuit. The current feedback value can also be adjusted to make the current value meet the requirements of accurate testing under high power. By dynamically adjusting the voltage and current values in this way, the battery test system can adapt to different temperature and power environments to ensure test accuracy.

[0015] Further preferably, the voltage and current setting mechanism provides preset voltage and current target values for the battery test and sets standard parameters for the test; Further preferably, the voltage-current conditioning conversion detection mechanism is used to condition, convert, and detect the collected voltage and current signals, and process the original signals into electrical signals that can be accurately measured and analyzed.

[0016] Further preferably, the switching tube driving mechanism adjusts the driving voltage amplitude or PWM pulse width according to the requirements of the system to control the current and voltage in the circuit, so as to offset the influence of temperature changes on the measured values.

[0017] Further preferably, the calibration method of the above battery test device includes the following steps: Step S1: The computer establishes a network connection with the battery test system through a switch, and communicates with the 6 1 / 2-digit bench meter through a serial cable. Step S2: Place the battery test system in a high and low temperature test chamber, and set different temperature environments through the high and low temperature test chamber. Step S3: The calibration tooling of the battery test system connects the battery and the resistor through a four-electrode channel line, and is also connected to the battery test system and the 6 1 / 2-digit bench meter. Step S4: Under different temperature environments, the battery test system tests the battery and the resistor. The 6 1 / 2-digit bench meter measures the actual voltage and current values, and transmits the data to the computer through the network cable and the serial cable. And the data is processed and analyzed through the BTS test software on the computer to calculate the calibration coefficient, and at the same time control the working state of the battery test system.

[0018] Among them, the BTS test software controls the operation of the battery test system. The voltage-current setting mechanism sets the target values of the test voltage and current. The ambient temperature is detected in real time through a temperature sensor, and the temperature data is transmitted to the voltage-current conditioning conversion detection mechanism. During the test process of the battery test system, the collected voltage and current signals are first processed by the voltage-current conditioning conversion detection mechanism. The calibration tooling of the battery test system connects the battery test system and the voltage-current detection mechanism and the 6 1 / 2-digit bench meter, and calibrates the battery test system under different temperature and power environments. The voltage-current detection mechanism cooperates with the 6 1 / 2-digit bench meter to measure the actual voltage and current values and feedback them to the battery test system. And according to the temperature data and the measured actual voltage and current values, the switching tube driving mechanism adjusts the driving voltage amplitude or PWM pulse width to compensate for the voltage and current, offset the influence of temperature changes on the measured values, and ensure the test accuracy.

[0019] The present invention has the following beneficial effects: The present invention significantly reduces the differences between the measured voltage value and the displayed voltage value, and between the measured current value and the displayed current value at different temperatures, improves the measured accuracy of voltage and current, thereby improving the overall measured accuracy and performance of the battery test system. That is to say, it can effectively reduce the deviation between the measured voltage value and the displayed voltage value, and between the measured current value and the displayed current value, effectively improve the accuracy of the measured voltage value and the measured current value, and effectively improve the overall high and low temperature adaptability of the battery test system. Through the dual mechanism of "segmented calibration + hardware compensation", the present invention systematically solves the interference of temperature on the battery test accuracy, enables the test system to maintain high reliability in complex environments, and promotes the development of battery test technology towards intelligence and high precision. Specifically, through two-dimensional segmentation of temperature-power: for example, the temperature is divided into low temperature, normal temperature, and high and low temperature segments, and the power is divided into low power, medium power, and high power levels, forming multiple calibration intervals. Calibration process: within each interval, more than 10 groups of measured voltage / current values are collected by a 6 1 / 2-digit bench meter (with an accuracy of 0.003%), compared with the displayed values of the test system, and the linear calibration coefficients (slope k, intercept b) are calculated. For example: V 校准 =V 显示 ×K + b; I 校准 =I 显示 ×K + b; Storage and call: Nine groups of coefficients are stored in the EEPROM of the test system, and the corresponding coefficients are called in real time according to the temperature sensor (with an accuracy of ±0.5°C) and the power level to achieve dynamic compensation. Hardware-level passive compensation optimizes the signal chain: Current compensation, the PWM pulse width (with a resolution of 1 μs) is adjusted through the switching tube drive mechanism to dynamically correct the voltage across the sampling resistor. For example, when the resistance value of the sampling resistor increases at high and low temperatures, resulting in a smaller measured current, the system automatically extends the PWM conduction time to boost the output current to the theoretical value. Voltage compensation: A thermistor network is introduced into the voltage conditioning circuit, and its resistance value changes with temperature to counteract the zero drift of the operational amplifier in the opposite direction. For example, when the temperature rises and causes the output of the operational amplifier to be positive, the resistance value of the thermistor decreases, pulling down the compensation voltage, so that the deviation between the finally measured voltage value and the displayed value < 0.2%.

[0020] Use a high and low temperature test chamber to simulate different temperature environments and place the battery test system in it. At different temperature segments, compare the measured values of the 6 1 / 2-digit bench meter with the displayed values of the battery test system, calculate the voltage and current calibration coefficients (slope k and intercept b) and store them. The temperature sensor detects the temperature in real time, and the test system calls the corresponding calibration coefficients according to the temperature threshold. By adjusting the drive voltage amplitude or PWM pulse width of the switching tube drive mechanism, voltage and current compensation are achieved to offset the influence of temperature on the measured values.

[0021] To more clearly elaborate on the structural features and effects of the present invention, the following will describe the present invention in detail in combination with the drawings and specific embodiments. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the principle of a battery testing device with passive temperature compensation mentioned in the present invention; Figure 2 It is a specific compensation schematic diagram of a battery testing device with passive temperature compensation mentioned in the present invention. Specific embodiments

[0023] The following will further illustrate the present invention in conjunction with the accompanying drawings and relevant knowledge, and will be described clearly and completely. Obviously, the described applications are only a part of the embodiments of the present invention, rather than all embodiments.

[0024] Refer to Figure 1 - Figure 2 As shown, a battery testing device with passive temperature compensation of the present invention includes a battery testing system, a battery testing system calibration tooling, a temperature sensor, a high and low temperature test chamber, a 6 1 / 2 - digit bench meter, a battery, a resistor, a communication line, and a computer. The battery testing system provides a testing platform, the battery testing system calibration tooling provides a calibration platform, the temperature sensor is used to detect the ambient temperature of the battery testing system, the high and low temperature test chamber is used to simulate the change of ambient temperature, the 6 1 / 2 - digit bench meter is used as the standard for measuring the actual current value, and the battery is the test object; among them, the 6 1 / 2 - digit bench meter is specifically used to test the actual current value and actual voltage value during battery testing or calibration, and use them as the reference standards for the displayed and actual values of battery voltage and current.

[0025] Specifically, use the high and low temperature test chamber to simulate different temperature environments, place the battery testing system in it, and then calibrate and store the actual voltage value and voltage display value, actual current value and current display value of the battery in different temperature environments in segments. Since temperature is a process quantity, the influence on the accuracy of the battery testing system for temperatures that are relatively close is not significant. Therefore, select a threshold for temperature - segmented calibration as the calibration parameter when the battery testing system calls different segments. Then, for constant - current charging, constant - current discharging, constant - voltage charging, and constant - voltage discharging, use the method of pre - discharging with non - fixed calibration segments and then calibrating during constant - voltage discharging. The compensation of voltage and current is achieved by changing the driving voltage amplitude or driving pulse width, and the driving voltage amplitude or driving pulse width is achieved by the passive compensation method of changing the voltage feedback value or current feedback value.

[0026] Example 1, refer to Figure 1 and Figure 2 As shown, where Figure 1 Specifically, the constant - temperature calibration block diagram of the battery testing system is used to calibrate the segmented calibration values of voltage and current at different temperatures, Figure 2 Specifically, it is the different - temperature compensation block diagram of the battery testing system. The different - temperature compensation block diagram of the battery testing system is used for voltage and current compensation in different temperature and different power environments, so as to improve the measurement accuracy of voltage and current.

[0027] In this embodiment, taking the measured and displayed current of a set of battery test systems operating at different ambient temperatures as an example, the present invention will be further described in detail.

[0028] Refer to Figure 1 , the battery test system is calibrated and connected, and the battery calibration tooling ensures that normal switching can be achieved for different channels, different modes, and different temperatures; the 6 1 / 2 digit bench meter, switch, network cable, and host computer software ensure that different segments, different measured voltages, different displayed voltages, different measured currents, and different displayed currents can be detected, and the corresponding k values and b values are transmitted to the host computer software; The battery ensures that different segments, different constant current charging, constant current discharging, different measured currents, and different displayed currents can be detected, and the corresponding k values and b values are transmitted to the host computer software; The battery ensures that different segments, different constant voltage discharging, different pre-discharge point settings, different measured voltages, and different displayed voltages can be detected, and the corresponding k values and b values are transmitted to the host computer software; The resistor ensures that different segments, different constant voltage charging, different measured voltages, and different displayed voltages can be detected, and the corresponding k values and b values are transmitted to the host computer software; Refer to Figure 2 , the battery test system detects different ambient temperatures through the built-in temperature sensor; the battery test system calls the corresponding k values and b values in the voltage and current conditioning and conversion detection mechanism through different temperature thresholds; The battery test system offsets the influence of temperature changes on the measured voltage and measured current by adjusting the voltage and current conversion values at different temperatures; the battery test system adjusts the driving voltage amplitude or PWM pulse width through the switching tube driving mechanism, thereby offsetting the influence of temperature changes on the measured voltage and measured current, and maintaining the high precision of the battery test system in high and low temperature environments.

[0029] Core issues and solutions of the present invention: Core issue: In the existing battery test system, changes in ambient temperature will cause temperature drift of the sampling resistor and temperature drift of the circuit zero point, resulting in inconsistent measured current and displayed current, especially in high and low temperature environments, the test accuracy of battery capacity drops significantly.

[0030] Solution: Through passive temperature compensation technology and segmented calibration method, eliminate the influence of temperature on current and voltage detection, and ensure a high degree of consistency between measured values and displayed values at different temperatures.

[0031] Passive temperature compensation mechanism: Compensation object: Current error: Temperature causes a change in the resistance value of the sampling resistor (temperature drift), which in turn causes a deviation in the measured current.

[0032] Voltage error: The slight influence of circuit zero point temperature drift on voltage detection.

[0033] Compensation method: By adjusting the driving voltage amplitude or PWM pulse width (switch driving mechanism), passively offset the change in resistance value caused by temperature and circuit drift. There is no need for active heating or cooling, and compensation is achieved only through circuit parameter adjustment, reducing system complexity and energy consumption.

[0034] Segmented calibration method: Calibration process: Temperature segmentation: Set multiple temperature thresholds in a high and low temperature test chamber, and each threshold serves as a calibration segment. Parameter acquisition: At each temperature segment, use a 6 1 / 2 digit bench meter to measure the actual current / voltage value, compare it with the display value of the test system, and calculate the calibration coefficients (slope K and intercept B).

[0035] Storage and call: Store the calibration coefficients of each segment in the test system. When the temperature sensor detects the current temperature, automatically call the coefficients of the corresponding segment for compensation.

[0036] Calibration scenarios: Constant current charge and discharge: Calibrate the temperature error at different current levels. Constant voltage charge and discharge: Set different voltage points through pre-discharge to calibrate the voltage detection error (with the resistor as the calibration object).

[0037] The technical principle of the present invention has been described above in combination with specific embodiments, which are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. Those skilled in the art can readily conceive of other specific embodiments of the present invention without creative labor, and these embodiments will all fall within the protection scope of the present invention.

Claims

1. A battery testing device with passive temperature compensation, characterized in that, It includes a battery test system, which is used to provide a test platform and is built-in with a temperature sensor, a voltage and current setting mechanism, a voltage and current conditioning, conversion and detection mechanism, and a switching tube driving mechanism; A calibration tooling for the battery test system, which is used to build a calibration platform, connect the battery test system and standard equipment, and achieve calibration under different temperatures / powers; A high and low temperature test chamber, which is used to simulate different temperature environments to provide test conditions; the calibration tooling for the battery test system is also connected with a resistor, a battery and a switch. The resistor is used to provide a calibration object and simulate different power loads, the battery is used to provide a test object, and the switch is used for real-time communication.

2. The battery testing device with passive temperature compensation according to claim 1, characterized in that, The standard equipment is a 6 1 / 2 digit bench meter: it is used to measure the measured current value and measured voltage value during battery test or calibration, and provide a reference standard for the displayed value and measured value of battery voltage and current.

3. A battery testing device with passive temperature compensation as described in claim 1, characterized in that, The voltage and current setting mechanism provides preset voltage and current target values for the battery test and sets the standard parameters of the test.

4. A battery testing device with passive temperature compensation according to claim 1, characterized in that, The voltage and current conditioning, conversion and detection mechanism is used to condition, convert and detect the collected voltage and current signals, and process the original signals into electrical signals that can be accurately measured and analyzed.

5. The battery testing device with passive temperature compensation according to claim 1, characterized in that, The switching tube driving mechanism adjusts the driving voltage amplitude or PWM pulse width according to the system requirements to control the current and voltage in the circuit, so as to offset the influence of temperature change on the measured value.

6. A calibration method for a battery testing device as claimed in claim 5, characterized in that, It includes the following steps: Step S1: The computer establishes a network connection with the battery test system through the switch, and communicates with the 6 1 / 2 digit bench meter through a serial cable at the same time; Step S2: Place the battery test system into the high and low temperature test chamber and set different temperature environments through the high and low temperature test chamber; Step S3: The calibration tooling for the battery test system connects the battery and the resistor through a four-electrode channel wire, and is connected to the battery test system and the 6 1 / 2 digit bench meter at the same time; Step S4: Under different temperature environments, the battery test system tests the battery and the resistor. The 6 1 / 2 digit bench meter measures the actual voltage and current values, and transmits the data to the computer through the network cable and the serial cable. And through the BTS test software on the computer, the data is processed and analyzed, the calibration coefficient is calculated, and the working state of the battery test system is controlled at the same time.

7. The calibration method according to claim 6, wherein The BTS test software controls the operation of the battery test system, and the voltage and current setting mechanism sets the voltage and current target values of the test.

8. The calibration method according to claim 7, wherein, The ambient temperature is detected in real time by the temperature sensor, and the temperature data is transmitted to the voltage and current conditioning, conversion and detection mechanism.

9. The calibration method according to claim 8, characterized in that, During the test process of the battery test system, the collected voltage and current signals are first processed by the voltage and current conditioning, conversion and detection mechanism.

10. The calibration method according to claim 9, characterized in that The calibration tooling for the battery test system is connected to the battery test system, the voltage and current detection mechanism, and the 6 1 / 2 digit bench meter. It calibrates the battery test system under different temperature and power environments. The voltage and current detection mechanism cooperates with the 6 1 / 2 digit bench meter to measure the actual voltage and current values and feedback them to the battery test system. And according to the temperature data and the actual measured voltage and current values, the switching tube driving mechanism adjusts the driving voltage amplitude or PWM pulse width to compensate the voltage and current, offset the influence of temperature change on the measured value, and ensure the test accuracy.

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