Battery self-discharge current testing device and testing method

Abstract

This application relates to the field of battery testing technology, and discloses a battery self-discharge current testing device and method. The self-discharge current testing device includes: a voltage acquisition circuit, an excitation current circuit, and a microcontroller. The microcontroller is used to control the output of the excitation current circuit to be zero at the beginning of the test and to acquire the initial voltage of the battery through the voltage acquisition circuit. During the test, the voltage acquisition circuit acquires the real-time voltage of the battery, and a first target excitation current is obtained based on the initial voltage and the real-time voltage. The excitation current circuit is then controlled to output an excitation current corresponding to the first target excitation current until the battery voltage remains stable. At this point, the current excitation current is determined to be the battery's self-discharge current. This technical solution avoids the errors caused by traditional voltage estimation methods, improves the accuracy and stability of micro-current measurement, and enhances the anti-interference capability and reliability of the testing process.

Description

Technical Field

[0001] This invention relates to the field of battery testing technology, and in particular to a battery self-discharge current testing device and testing method. Background Technology

[0002] With the widespread application of lithium-ion batteries and other types of batteries in energy storage systems, electric devices, and consumer electronics, the importance of battery performance testing technology is becoming increasingly prominent. Among them, self-discharge current, as an important parameter characterizing the internal leakage characteristics and consistency of a battery, directly affects the battery's storage performance and lifespan. Therefore, accurate measurement of battery self-discharge current is of great significance.

[0003] In existing technologies, battery self-discharge current is typically measured indirectly by voltage changes or directly by high-precision current detection equipment. However, since battery self-discharge current is usually in the microampere range or even lower, direct measurement is difficult, requiring high accuracy and stability from the detection circuit, and is easily affected by environmental interference, leading to unstable measurement results. Furthermore, voltage-based estimation methods often rely on long-term static testing, resulting in a long testing cycle, and it is difficult to eliminate the influence of external conditions on the results during the testing process, thus reducing measurement accuracy. Summary of the Invention

[0004] This invention provides a battery self-discharge current testing device and method to solve the above-mentioned technical problems.

[0005] The first aspect of this invention provides a battery self-discharge current testing device, comprising: Voltage acquisition circuit, which is connected to the battery; Excitation current circuit, which is electrically connected to the battery; The microcontroller is connected to both the voltage acquisition circuit and the excitation current circuit. The microcontroller is used to control the output current of the excitation current circuit to be zero at the start of the test and to obtain the initial voltage of the battery through the voltage acquisition circuit. During the test, the real-time voltage of the battery is obtained through the voltage acquisition circuit. Based on the initial voltage and the real-time voltage, the first target excitation current is obtained, and the excitation current circuit is controlled to output the excitation current corresponding to the first target excitation current until the battery voltage remains stable. Then, the current excitation current is determined to be the self-discharge current of the battery.

[0006] Optionally, the microcontroller calculates the first target excitation current I according to the following formula. t1 : I t1 =(U0-U t ) / R; Where U0 is the initial voltage, U t R is the real-time voltage, and R is the equivalent impedance of the circuit.

[0007] Optionally, the microcontroller is configured to: control the excitation current circuit to gradually adjust the output excitation current according to a preset adjustment step size, so that the output excitation current gradually approaches the first target excitation current; detect the voltage change trend of the battery after each adjustment; when a reversal of the voltage change direction is detected, reduce the adjustment step size and readjust the output excitation current; until the adjustment step size is less than a preset threshold, determine the current excitation current as the self-discharge current of the battery.

[0008] Optionally, the self-discharge current testing device also includes: Temperature acquisition circuit, which is connected to both the battery and the microcontroller; The microcontroller is also used to control the output current of the excitation current circuit to be zero at the start of the test, and to obtain the initial voltage of the battery through the voltage acquisition circuit and the initial temperature of the battery through the temperature acquisition circuit. During the test, the microcontroller obtains the real-time voltage of the battery through the voltage acquisition circuit and the real-time temperature of the battery through the temperature acquisition circuit. Based on the initial voltage, real-time voltage, initial temperature and real-time temperature, the microcontroller obtains the second target excitation current and controls the excitation current circuit to output the excitation current corresponding to the second target excitation current until the battery voltage remains stable. At this point, the current excitation current is determined to be the self-discharge current of the battery.

[0009] Optionally, the microcontroller calculates the second target excitation current I according to the following formula. t2 : I t2 =(U0-(U t -(T0-T t )*k)) / R; Where U0 is the initial voltage, U t T is the real-time voltage, T0 is the initial temperature, and T t R is the real-time temperature, R is the equivalent impedance of the circuit, and k is the temperature coefficient of the battery.

[0010] Optionally, the excitation current circuit includes: The digital-to-analog converter module has its input connected to the output of the microcontroller. The voltage-to-current conversion circuit has its input terminal connected to the output terminal of the digital-to-analog conversion module. The first output terminal of the voltage-to-current conversion circuit is connected to the positive terminal of the battery through the first branch line, and the second output terminal of the voltage-to-current conversion circuit is connected to the negative terminal of the battery through the second branch line. The microcontroller outputs digital control signals to the digital-to-analog converter module, which converts them into analog voltage signals and then inputs them to the voltage-to-current conversion circuit to control the voltage-to-current conversion circuit to output the corresponding excitation current.

[0011] Optionally, the voltage acquisition circuit includes: The first filter circuit has its first input terminal connected to the positive terminal of the battery via a third branch line, and its second input terminal connected to the negative terminal of the battery via a fourth branch line. The first analog-to-digital driver circuit has its input terminal connected to the output terminal of the first filter circuit. The analog-to-digital converter module has its first input terminal connected to the output terminal of the first analog-to-digital driver circuit, and its output terminal connected to the input terminal of the microcontroller. The first filter circuit is used to filter the voltage signal at both ends of the battery to reduce noise interference. The first analog-to-digital driver circuit is used to buffer and amplify the filtered voltage signal to match the input range of the analog-to-digital converter module; The analog-to-digital converter module is used to convert voltage signals into digital signals and send them to the microcontroller.

[0012] Optionally, the self-discharge current testing device also includes: The input of the second filter circuit is connected to the output of the voltage-to-current conversion circuit. The second analog-to-digital driver circuit has its input terminal connected to the output terminal of the first filter circuit, and its output terminal connected to the second input terminal of the analog-to-digital converter module. The second filter circuit is used to filter the excitation current signal to reduce noise interference; The second analog-to-digital driver circuit is used to buffer and adjust the amplitude of the filtered excitation current signal to match the input range of the analog-to-digital conversion module; The analog-to-digital conversion module is used to convert the excitation current signal from analog to digital and send the corresponding digital signal to the microcontroller so that the microcontroller can monitor or calibrate the excitation current.

[0013] Optionally, the self-discharge current testing device also includes: A voltage reference module is connected to both the digital-to-analog converter module and the analog-to-digital converter module, and is used to provide a reference voltage to both modules.

[0014] Embodiment 2 of the present invention provides a test method for a battery self-discharge current test device based on Embodiment 1. The test method includes: At the start of the test, the output current of the excitation current circuit is controlled to be zero, and the initial voltage of the battery is obtained through the voltage acquisition circuit. During the test, the real-time voltage of the battery is acquired through a voltage acquisition circuit, and the first target excitation current is obtained based on the initial voltage and the real-time voltage. The excitation current circuit outputs an excitation current corresponding to the first target excitation current until the battery voltage remains stable, at which point the current excitation current is determined to be the battery's self-discharge current.

[0015] Embodiment 3 of the present invention provides a test method for a battery self-discharge current test device based on Embodiment 1. The test method includes: At the start of the test, the output current of the excitation current circuit is controlled to be zero, and the initial voltage of the battery is obtained through the voltage acquisition circuit, and the initial temperature of the battery is obtained through the temperature acquisition circuit. During the test, the real-time voltage of the battery is obtained through the voltage acquisition circuit, and the real-time temperature of the battery is obtained through the temperature acquisition circuit. The second target excitation current is obtained based on the initial voltage, real-time voltage, initial temperature and real-time temperature. The excitation current circuit outputs an excitation current corresponding to the second target excitation current until the battery voltage remains stable, at which point the current excitation current is determined to be the battery's self-discharge current.

[0016] The technical effects of this invention are as follows: This technical solution constructs a test mechanism for voltage monitoring and dynamic current approximation, so that the excitation current is gradually adjusted to balance with the battery self-discharge current, thereby directly obtaining the target current value under stable voltage conditions, avoiding the errors caused by the traditional voltage estimation method, improving the accuracy and stability of micro-current measurement, and enhancing the anti-interference ability and reliability of the test process. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the first structure of a battery self-discharge current testing device provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the second structure of a battery self-discharge current testing device provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the third structure of a battery self-discharge current testing device provided in Embodiment 1 of the present invention; Figure 4 This is a flowchart of a test method for a battery self-discharge current testing device provided in Embodiment 2 of the present invention; Figure 5 This is a flowchart of a test method for a battery self-discharge current test device provided in Embodiment 3 of the present invention; In the diagram: 101, Battery; 102, Voltage Acquisition Circuit; 103, Excitation Current Circuit; 104, Microcontroller; 201, First Filter Circuit; 202, First Analog-to-Digital Driver Circuit; 203, Analog-to-Digital Conversion Module; 204, Second Filter Circuit; 205, Second Analog-to-Digital Driver Circuit; 206, Voltage-to-Current Conversion Module; 207, Digital-to-Analog Conversion Module; 208, Temperature Sensor; 209, Temperature Acquisition Module; 210, Voltage Reference Provision Module; 211, Signal Isolation Module; 212, Host Computer. Detailed Implementation

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

[0020] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0021] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0022] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0023] To fully understand this invention, detailed structures and steps will be presented in the following description to illustrate the technical solution proposed by this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0024] Example 1 This embodiment provides a battery self-discharge current testing device, comprising: Voltage acquisition circuit 102 is connected to battery 101; Excitation current circuit 103 is electrically connected to battery 101; Microcontroller 104 is connected to voltage acquisition circuit 102 and excitation current circuit 103 respectively; The microcontroller 104 is used to control the output current of the excitation current circuit 103 to be zero at the beginning of the test and to obtain the initial voltage of the battery 101 through the voltage acquisition circuit 102. During the test, the microcontroller obtains the real-time voltage of the battery 101 through the voltage acquisition circuit 102, obtains the first target excitation current based on the initial voltage and the real-time voltage, and controls the excitation current circuit 103 to output the excitation current corresponding to the first target excitation current until the voltage of the battery 101 remains stable, and then determines the current excitation current as the self-discharge current of the battery 101.

[0025] In this embodiment, a battery self-discharge current testing device is provided, which mainly includes a voltage acquisition circuit 102, an excitation current circuit 103, and a microcontroller 104. The modules work together to achieve accurate measurement of the self-discharge current of the battery 101.

[0026] The voltage acquisition circuit 102 is used to acquire the voltage signal across the battery 101 under test. This circuit uses a high-input-impedance sampling structure to detect the terminal voltage of the battery 101 and performs necessary conditioning processing on the acquired analog voltage signal, such as filtering and buffering, to improve signal stability and anti-interference capability. This circuit can continuously output voltage information reflecting the state changes of the battery 101, providing basic data for subsequent calculations. The excitation current circuit 103 is used to apply a controllable current to the battery 101 under test. This circuit can adopt a current source structure, outputting a corresponding current value according to the control signal, so that the current applied to the battery 101 can change according to a preset rule. By precisely adjusting the output current, it gradually approaches the self-discharge current level of the battery 101, thereby achieving the measurement purpose. At the same time, this circuit can ensure the stability and continuity of the output current, avoiding additional disturbances to the battery 101. The microcontroller 104, as the core control unit, is used to coordinate the operation of various functional modules. Specifically, in the initial stage of testing, the microcontroller 104 controls the excitation current circuit 103 to output zero current and acquires the initial voltage value of the battery 101 through the voltage acquisition circuit 102. Subsequently, during the test, the microcontroller 104 periodically receives the real-time voltage data output by the voltage acquisition circuit 102 and calculates the target excitation current based on the relationship between the initial voltage and the current voltage. Further, the microcontroller 104 outputs a control signal to adjust the excitation current circuit 103 so that its output current matches the target value. The excitation current output corresponding to the first target excitation current means that the excitation current circuit generates a current output with a preset correspondence to the first target excitation current according to the control signal output by the microcontroller. The preset correspondence can be an equality relationship, a proportional relationship, or a mapping relationship. Preferably, the excitation current output by the excitation current circuit is equal to the first target excitation current, that is, the excitation current circuit outputs an excitation current of a corresponding magnitude according to the value of the first target excitation current; or, the excitation current output by the excitation current circuit satisfies a preset proportional relationship with the first target excitation current, so as to combine the circuit amplification factor, current conversion coefficient, or range adjustment parameters for output control. By establishing a definite correspondence between the excitation current and the first target excitation current, the excitation current circuit can accurately output the current that meets the compensation requirements, thereby improving the control precision and measurement accuracy during the battery self-discharge current test. As time progresses, when the voltage at the battery 101 terminal stabilizes and remains within a certain range, it indicates that the applied excitation current has reached a balance with the self-discharge current of the battery 101. At this point, the current excitation current is determined as the self-discharge current of the battery 101. The phrase "until the battery voltage remains stable" means that the microcontroller continuously monitors the real-time voltage of the battery and determines that the battery voltage remains stable when it detects that the battery voltage meets the preset stability conditions within a preset time period.Specifically, the preset stability conditions can be: the change amplitude of the real-time voltage within multiple consecutive sampling periods is less than a preset voltage threshold; or, the difference between two adjacent samplings of the real-time voltage is less than a preset difference threshold; or, the fluctuation range of the real-time voltage within a preset time window is less than a preset fluctuation range; or, the rate of change of the real-time voltage is less than a preset rate of change threshold. Further, when the battery voltage is detected to remain stable, it indicates that the current excitation current has reached a state of equilibrium or near equilibrium with the battery's self-discharge current. At this time, the net charge / discharge current of the battery approaches zero, therefore, the current excitation current can be determined as the battery's self-discharge current. By setting voltage stability judgment conditions, misjudgments caused by instantaneous fluctuations, sampling noise, or environmental interference can be avoided, thereby improving the accuracy and reliability of the self-discharge current test results. Through the above structure and control process, this embodiment realizes a self-discharge current measurement mechanism based on dynamic current adjustment, which can more accurately reflect the true self-discharge characteristics of battery 101 compared to traditional methods.

[0027] This technology constructs a "voltage monitoring + current dynamic approximation" testing mechanism, which gradually adjusts the excitation current to balance with the battery's self-discharge current, thereby directly obtaining the target current value under stable voltage conditions. This avoids the errors caused by traditional voltage estimation methods, while improving the accuracy and stability of micro-current measurement and enhancing the anti-interference capability and reliability of the testing process.

[0028] As one implementation, the microcontroller 104 calculates the first target excitation current I according to the following formula. t1 : I t1 =(U0-U t ) / R; Where U0 is the initial voltage, U t R is the real-time voltage, and R is the equivalent impedance of the circuit.

[0029] In the initial stage of the test, the microcontroller 104 first controls the excitation current circuit 103 to be in a zero-output state. At this time, the battery 101 is not subjected to additional excitation current, and the acquired terminal voltage can be used as a reference for the subsequent adjustment process, i.e., the initial voltage U0. Subsequently, as the test progresses, the voltage acquisition circuit 102 continuously acquires the terminal voltage of the battery 101 at the current moment and transmits the corresponding voltage signal to the microcontroller 104. The microcontroller 104 then obtains the real-time voltage U0 based on this signal. t .

[0030] After obtaining the initial voltage U0 and the real-time voltage U t Then, the microcontroller 104 compares the two to obtain the change in the battery 101 terminal voltage relative to the initial state. Since the battery 101 experiences a gradual decrease in terminal voltage during self-discharge, the initial voltage U0 and the real-time voltage U...t The difference between the values ​​can characterize the degree of voltage decay of battery 101 at the current stage. The microcontroller 104 then combines the pre-set or calibrated equivalent circuit impedance R to convert the voltage difference, thereby obtaining the first target excitation current It1 corresponding to the current voltage change.

[0031] The equivalent impedance R of the circuit can be understood as the comprehensive impedance parameter in the test circuit that affects the current regulation relationship. Its value can be predetermined based on the circuit structure, wire parameters, interface connection status, and characteristics of related components. Using this parameter, the detected voltage deviation can be mapped to the magnitude of the compensation current that should be applied. In other words, when the real-time voltage U... t As the decrease in voltage U0 increases, the calculated first target excitation current It1 also increases accordingly; conversely, when the real-time voltage is close to the initial voltage, the target current value is relatively small. In this way, the direction and magnitude of the excitation current adjustment can be matched with the actual voltage change state of the battery 101.

[0032] In actual operation, the microcontroller 104 calculates the first target excitation current It1 in real time according to the above formula, and converts the calculation result into a corresponding control signal and sends it to the excitation current circuit 103, causing the excitation current circuit 103 to output a current corresponding to the target value. As the test continues, the output current gradually changes and approaches the actual self-discharge current of the battery 101. When the applied excitation current and the self-discharge current of the battery 101 reach equilibrium, the terminal voltage of the battery 101 will no longer continue to drop significantly, but will enter a basically stable state. At this time, the currently output excitation current can be used as the test result of the self-discharge current of the battery 101.

[0033] In this way, the microcontroller 104 does not need to directly measure the extremely weak self-discharge current itself. Instead, it indirectly obtains the target excitation current through the correspondence between voltage change and equivalent impedance, and then uses the excitation current to dynamically compensate for the self-discharge effect, thereby achieving effective testing of the self-discharge current. This implementation method has clear calculation logic, easy-to-implement control process, and is easy to programmatically deploy in the microcontroller 104.

[0034] This embodiment establishes a functional relationship between the initial voltage, real-time voltage, and equivalent impedance of the circuit, enabling the microcontroller 104 to calculate the target excitation current in real time based on the change in the terminal voltage of the battery 101, and drive the excitation current circuit 103 to output the corresponding current, thereby gradually approximating the actual self-discharge current of the battery 101 in a dynamic compensation manner. This scheme not only simplifies the process of obtaining the self-discharge current, but also improves the feasibility, measurement accuracy, and result stability of micro-current testing.

[0035] In one implementation, the microcontroller 104 is configured to: control the excitation current circuit to gradually adjust the output excitation current according to a preset adjustment step size, so that the output excitation current gradually approaches the first target excitation current; detect the voltage change trend of the battery after each adjustment; when the voltage change direction is detected to be reversed, reduce the adjustment step size and readjust the output excitation current; until the adjustment step size is less than a preset threshold, determine that the current excitation current is the self-discharge current of the battery.

[0036] In this embodiment, to further improve the measurement accuracy of the self-discharge current, after acquiring the first target excitation current, the microcontroller 104 does not directly control the excitation current circuit to output the corresponding current all at once. Instead, it adjusts the output current stepwise based on a preset adjustment step size, gradually increasing or decreasing the output current so that the actual output excitation current gradually approaches the first target excitation current. Specifically, after each current adjustment, the microcontroller 104 acquires the current voltage change state of the battery through the voltage acquisition circuit and analyzes the voltage change trend compared to the previous detection cycle to determine whether the current excitation current adjustment direction is correct. When it detects that the battery voltage change direction has reversed compared to the previous detection result, it can be considered that the current output excitation current has exceeded the equilibrium point corresponding to the actual self-discharge current of the battery. At this time, the microcontroller 104 reduces the currently used adjustment step size and, based on the reduced adjustment step size, re-controls the excitation current circuit to finely adjust the output excitation current, thereby reducing the change amplitude of each adjustment and improving the approximation accuracy. As the adjustment process continues, the adjustment step size gradually decreases. When the adjustment step size decreases to less than the preset threshold, it indicates that the current excitation current is close enough to the actual self-discharge current of the battery. At this time, the current excitation current is determined as the self-discharge current of the battery.

[0037] This implementation method iteratively optimizes the output excitation current by gradually approximating and dynamically reducing the adjustment step size. This avoids overshoot or adjustment errors caused by directly outputting the target current, improves the matching accuracy between the excitation current and the actual self-discharge current, and thus enhances the accuracy, stability, and reliability of the self-discharge current measurement results.

[0038] In one implementation, the microcontroller 104 is also configured to: Once the battery voltage is detected to meet the preset stability condition, the current excitation current is maintained for the preset verification time. If the battery voltage continuously meets the preset stability condition within the preset verification time, then the current excitation current is determined to be the battery's self-discharge current.

[0039] In this process, after the microcontroller 104 determines that the battery voltage has reached a preset stable condition, it does not immediately identify the current excitation current as the battery's self-discharge current. Instead, it controls the excitation current circuit to maintain the current output state, ensuring that the current excitation current continues to act on the battery for a preset verification period. During this verification phase, the microcontroller 104 continues to monitor the battery terminal voltage in real time through the voltage acquisition circuit and continuously analyzes the acquired voltage data to determine whether the battery voltage remains within the preset stable range throughout the verification cycle. If the battery voltage does not exceed the preset stable range within the preset verification period, it indicates that the current excitation current can stably compensate for the battery's self-discharge loss over the duration. Based on this, the microcontroller 104 confirms that the current output excitation current matches the actual self-discharge current of the battery and identifies this excitation current as the battery's self-discharge current. If, during the verification process, fluctuations in the battery voltage exceeding the preset range are detected again, it is determined that the current excitation current has not yet reached a stable compensation state. The microcontroller 104 continues to perform subsequent adjustment operations to readjust the output excitation current.

[0040] This implementation adds a continuous verification phase after the battery voltage reaches a stable condition, and further confirms the voltage stability state within the verification period. This avoids misjudgment caused by instantaneous noise interference, sampling errors, or short-term voltage fluctuations, thereby improving the accuracy, stability, and reliability of the self-discharge current determination result.

[0041] As one implementation method, such as Figure 2 As shown, the self-discharge current testing device also includes: Temperature acquisition circuit 105 is connected to battery 101 and microcontroller 104 respectively. The microcontroller 104 is also used to control the output current of the excitation current circuit 103 to be zero at the start of the test, and to obtain the initial voltage of the battery 101 through the voltage acquisition circuit 102 and the initial temperature of the battery 101 through the temperature acquisition circuit 105; during the test, it obtains the real-time voltage of the battery 101 through the voltage acquisition circuit 102 and the real-time temperature of the battery 101 through the temperature acquisition circuit 105, obtains the second target excitation current based on the initial voltage, real-time voltage, initial temperature and real-time temperature, and controls the excitation current circuit 103 to output the excitation current corresponding to the second target excitation current, until the voltage of the battery 101 remains stable, and determines the current excitation current as the self-discharge current of the battery 101.

[0042] The self-discharge current testing device may further include a temperature acquisition circuit 105, which is connected to both the battery 101 and the microcontroller 104. This circuit detects the temperature changes of the battery 101 during the test and transmits the corresponding temperature information to the microcontroller 104. Since the terminal voltage of the battery 101 is not only related to the self-discharge process but also affected by ambient temperature and fluctuations in the battery's own temperature, introducing a temperature acquisition function during the test helps improve the accuracy of the self-discharge current determination.

[0043] Specifically, the temperature acquisition circuit 105 can be positioned close to the battery 101 body to acquire temperature signals that reflect the thermal state of the battery 101. After appropriate processing, this temperature signal is input to the microcontroller 104, so that the microcontroller 104 considers the influence of temperature on voltage when analyzing changes in the battery 101 voltage. In this way, the device can not only grasp the trend of voltage changes at the battery 101 terminals but also simultaneously obtain temperature change information of the battery 101 throughout the entire test cycle, thus providing a data basis for subsequent compensation calculations.

[0044] At the start of the test, the microcontroller 104 first controls the excitation current circuit 103 to output zero, placing the battery 101 in an initial test state without external compensation current. In this state, the microcontroller 104 acquires the initial voltage of the battery 101 through the voltage acquisition circuit 102 and uses it as a reference value for subsequent voltage changes. Simultaneously, the microcontroller 104 also reads the initial temperature of the battery 101 through the temperature acquisition circuit 105 to characterize the thermal state at the start of the test. The initial voltage and initial temperature together constitute the initial parameters of the test model, providing a benchmark for subsequent dynamic adjustments.

[0045] After entering the testing process, the voltage acquisition circuit 102 continuously outputs the real-time voltage signal of the battery 101 at the current moment, while the temperature acquisition circuit 105 simultaneously provides the real-time temperature information corresponding to that moment. After receiving these two types of data, the microcontroller 104 compares the current voltage with the initial voltage and, combined with the difference between the real-time temperature and the initial temperature, performs a correction analysis on the voltage change at the battery 101 terminal. Since temperature changes may cause the open-circuit voltage of the battery 101 to drift, if the excitation current is calculated directly based solely on the voltage difference, the voltage change caused by temperature may be misjudged as voltage decay caused by self-discharge. Therefore, the microcontroller 104 obtains the second target excitation current by comprehensively considering the initial voltage, real-time voltage, initial temperature, and real-time temperature to reduce the interference of temperature factors on the measurement results.

[0046] After obtaining the second target excitation current, the microcontroller 104 outputs a corresponding control signal to the excitation current circuit 103, causing the excitation current circuit 103 to generate an excitation current corresponding to the second target excitation current and apply this excitation current to both ends of the battery 101. As the test time progresses, the microcontroller 104 continuously updates the target excitation current based on newly acquired voltage and temperature data, and the excitation current circuit 103 adjusts its output according to the updated results. In this way, the applied excitation current can be dynamically adjusted according to the changes in the state of the battery 101, gradually approaching the current level that can counteract the self-discharge effect of the battery 101.

[0047] When the microcontroller 104 detects that the terminal voltage of the battery 101 remains essentially constant over a period of time, it can be considered that the currently output excitation current has reached a balance with the self-discharge current of the battery 101. In other words, at this time, the applied excitation current compensates for the voltage drop of the battery 101 caused by self-discharge, preventing the terminal voltage of the battery 101 from changing significantly. Therefore, the microcontroller 104 determines the excitation current corresponding to this moment as the self-discharge current of the battery 101. Compared with the method of compensation based solely on voltage changes, this embodiment further introduces the temperature dimension, making the acquisition process of the self-discharge current more consistent with the actual operating conditions of the battery 101.

[0048] Furthermore, the temperature acquisition circuit 105 can be implemented using a thermistor, a digital temperature sensor, or other devices suitable for temperature detection of the battery 101; the microcontroller 104 can then separate the voltage deviation caused by temperature changes from the total voltage change according to a preset temperature compensation model, and then calculate the corresponding second target excitation current. With the above approach, the device can maintain good measurement consistency and result reliability even under conditions of fluctuating ambient temperature or self-heating of the battery 101.

[0049] This embodiment adds a temperature acquisition circuit 105 to the self-discharge current testing device, so that the microcontroller 104 can consider the combined effects of voltage and temperature changes on the state of the battery 101 when adjusting the excitation current. This can compensate for the voltage drift caused by temperature, reduce the possibility of misjudging the thermal effect as the effect of self-discharge, and thus improve the accuracy, stability and environmental adaptability of the self-discharge current measurement results.

[0050] As one implementation, the microcontroller 104 calculates the second target excitation current I according to the following formula. t2 : I t2 =(U0-(U t -(T0-T t )*k)) / R; Where U0 is the initial voltage, U tT is the real-time voltage, T0 is the initial temperature, and T t R is the real-time temperature, R is the equivalent impedance of the circuit, and k is the temperature coefficient of battery 101.

[0051] Specifically, at the start of the test, the microcontroller 104 first controls the excitation current circuit 103 to output zero, so that the battery under test 101 is in a state without external compensation current applied. At this time, the initial voltage U0 across the battery 101 is obtained through the voltage acquisition circuit 102, and the corresponding initial temperature T0 is obtained through the temperature acquisition circuit 105. The above two initial parameters reflect the electrical and thermal states of the battery 101 at the start of the test, respectively, and can be used as reference benchmarks in the subsequent dynamic adjustment process.

[0052] During the test, the voltage acquisition circuit 102 continuously acquires the current terminal voltage of the battery 101, while the temperature acquisition circuit 105 synchronously detects the current temperature of the battery 101. Based on this, the microcontroller 104 obtains the real-time voltage U. t and real-time temperature T t Since the voltage change at the battery 101 terminal during the test is not entirely caused by self-discharge, temperature fluctuations can also cause the battery 101 voltage to deviate. Therefore, calculating the current solely based on the difference between the initial voltage and the real-time voltage may result in the calculation results being affected by temperature factors. To address this, this embodiment introduces a temperature compensation term in the current calculation process to improve the accuracy of obtaining the second target excitation current.

[0053] Specifically, in the formula (T0-T) t The coefficient k is used to characterize the voltage correction caused by temperature changes. If the temperature of battery 101 changes compared to its initial temperature during the test, the product of this temperature difference and the temperature coefficient k reflects the degree of influence of the temperature change on the voltage of battery 101. The microcontroller 104 first measures the real-time voltage U... t After correction, the equivalent voltage value after deducting the temperature effect is obtained, i.e., U. t -(T0-T t )×k. Then, the initial voltage U0 is compared with the corrected equivalent voltage to obtain a voltage change that more accurately reflects the self-discharge effect. Finally, the microcontroller 104, in conjunction with the circuit's equivalent impedance R, converts this voltage change into the second target excitation current I. t2 When the real-time voltage drops and the effect of temperature changes on the voltage is small or has been corrected, the calculated second target excitation current I... t2The voltage will increase accordingly, and the microcontroller 104 will control the excitation current circuit 103 to output a larger compensation current; conversely, when the voltage change after temperature correction is small, the calculated target current value will also decrease. With the help of this calculation method, the output of the excitation current can be closer to the actual self-discharge state of the battery 101, reducing the accumulation of errors caused by temperature fluctuations.

[0054] The equivalent impedance R of the circuit can be an impedance parameter that comprehensively reflects the influence of wires, circuit interfaces, and related devices on the current regulation relationship in the test circuit. It can be obtained through presetting, calibration, or experimental measurement. The temperature coefficient k can be determined based on the battery type, material system, or historical test data, and is used to describe the correspondence between temperature change and voltage change. By presetting the equivalent impedance R and temperature coefficient k, the microcontroller 104 can directly call the above formulas for real-time calculation during the test, thereby quickly obtaining the second target excitation current I. t2 And output the corresponding control signal to the excitation current circuit 103.

[0055] Throughout the test cycle, the microcontroller 104 continuously repeats the above calculation and adjustment process, causing the excitation current circuit 103 to update the output current in real time according to the new calculation results. As the applied excitation current gradually changes, when it reaches a level that balances with the self-discharge current of the battery 101, the terminal voltage of the battery 101 will tend to stabilize. At this point, the currently output excitation current can be identified as the self-discharge current of the battery 101. Compared to calculation methods that do not consider temperature factors, this embodiment, by introducing initial temperature, real-time temperature, and temperature coefficient into the model, can more accurately distinguish between the self-discharge component and the temperature component in voltage changes, and is therefore more suitable for test scenarios with significant temperature variations.

[0056] This embodiment constructs a target excitation current calculation model that includes a temperature compensation term, enabling the microcontroller 104 to simultaneously consider the impact of voltage and temperature changes on the measurement results during the battery 101 testing process. It also separates the voltage deviation caused by temperature from the total voltage change and calculates the second target excitation current in combination with the equivalent impedance of the loop. This improves the accuracy of self-discharge current measurement, reduces interference caused by ambient temperature fluctuations, and enhances the stability and applicability of the test results.

[0057] In one implementation, the microcontroller 104 is configured to: control the excitation current circuit to gradually adjust the output excitation current according to a preset adjustment step size, so that the output excitation current gradually approaches the second target excitation current; and determine the target adjustment step size according to the temperature change range between the real-time temperature and the initial temperature, and control the excitation current circuit to gradually adjust the output excitation current according to the target adjustment step size, so that the output excitation current gradually approaches the second target excitation current, wherein the target adjustment step size is negatively correlated with the temperature change range.

[0058] In this process, after the microcontroller 104 acquires the second target excitation current, it first controls the excitation current circuit to progressively adjust the output excitation current with a pre-set basic adjustment step size, gradually bringing the excitation current closer to the second target excitation current, thus completing the initial stage of rapid approximation. Subsequently, the microcontroller 104 further acquires the current real-time temperature of the battery and compares it with the initial temperature recorded at the start of the test to determine the temperature change amplitude during the current test. After determining the temperature change amplitude, the microcontroller 104 generates a target adjustment step size based on a preset temperature-step size correspondence. The larger the temperature change amplitude, the smaller the generated target adjustment step size, thus reducing the amplitude of a single adjustment. Afterwards, the microcontroller 104 controls the excitation current circuit to gradually correct the output excitation current again according to the target adjustment step size, allowing the output excitation current to continue approaching the second target excitation current. Through this method, when the temperature change is small, the system can use a larger adjustment step size to improve the excitation current adjustment efficiency; while when the temperature fluctuation is large, the adjustment step size is reduced to decrease the current change caused by each adjustment, thereby avoiding the problem of excitation current adjustment overshoot or increased adjustment error due to drastic temperature changes.

[0059] This embodiment dynamically adjusts the adjustment step size by combining the temperature change amplitude during the process of the excitation current approaching the second target excitation current. This enables the adjustment process of the excitation current to be adaptively optimized according to the actual thermal state of the battery. While ensuring the adjustment efficiency, it reduces the impact of temperature fluctuations on the current control accuracy, thereby improving the accuracy, stability and environmental adaptability of self-discharge current measurement.

[0060] Furthermore, the microcontroller 104 is also configured as follows: Obtain the current deviation between the output excitation current and the second target excitation current; When the current deviation is greater than the first preset threshold, the control excitation current circuit adjusts the output excitation current according to the first adjustment step size; When the current deviation is less than or equal to the first preset threshold, the control excitation current circuit adjusts the output excitation current according to the second adjustment step size; The first adjustment step size is greater than the second adjustment step size.

[0061] After determining the target adjustment step size based on the temperature change between the real-time temperature and the initial temperature, the microcontroller 104 also acquires the current deviation between the current output excitation current and the second target excitation current, and further adjusts the adjustment strategy of the output excitation current based on the current deviation. Specifically, when the current deviation is greater than a preset threshold, it indicates that the current output excitation current is significantly different from the target value. In this case, the microcontroller 104 controls the excitation current circuit to adjust with a larger adjustment step size to improve the current approximation efficiency. When the current deviation is less than or equal to the preset threshold, it indicates that the current output excitation current is close to the second target excitation current. In this case, the microcontroller 104 controls the excitation current circuit to adjust with a smaller adjustment step size to reduce the adjustment amplitude and improve the current adjustment accuracy, thereby making the output excitation current more smoothly approach the second target excitation current.

[0062] This implementation method further adjusts the output excitation current adjustment step size by combining the temperature adaptive adjustment step size with the current deviation size, so that the excitation current can quickly approach the target value when the deviation is large and can be finely adjusted when the deviation is small. This balances adjustment efficiency and control accuracy, and improves the accuracy and stability of self-discharge current testing.

[0063] As one implementation method, such as Figure 3 As shown, the excitation current circuit 103 includes: The digital-to-analog converter module 207 has its input terminal connected to the output terminal of the microcontroller 104. The voltage-to-current conversion circuit 206 has its input terminal connected to the output terminal of the digital-to-analog conversion module 207. The first output terminal of the voltage-to-current conversion circuit 206 is connected to the positive terminal of the battery 101 through a first branch line, and the second output terminal of the voltage-to-current conversion circuit 206 is connected to the negative terminal of the battery 101 through a second branch line. The microcontroller 104 outputs digital control signals to the digital-to-analog converter module 207, which converts the signals into analog voltage signals and then inputs them to the voltage-to-current converter circuit 206 to control the voltage-to-current converter circuit 206 to output the corresponding excitation current.

[0064] The excitation current circuit 103 is used to provide an adjustable current excitation to the battery under test 101. Its internal structure includes a digital-to-analog converter module 207 and a voltage-to-current converter circuit 206. The two work together under the control of the microcontroller 104 to achieve precise adjustment of the output current.

[0065] The digital-to-analog converter (DAC) module 207 receives the digital control signals output by the microcontroller 104. This module converts discrete digital quantities into continuously changing analog voltage signals. Specifically, after calculating the target excitation current value based on the current state of the battery 101, the microcontroller 104 maps this current value to a specific digital control quantity and outputs it to the DAC module 207. Upon receiving this digital signal, the DAC module 207 generates a corresponding analog voltage through its internal conversion mechanism. The magnitude of this analog voltage reflects the changing trend of the target current, thus providing a control basis for subsequent circuits.

[0066] The main function of the voltage-to-current conversion circuit 206 is to generate a corresponding current output based on the input analog voltage signal. This circuit can be implemented using a constant current source structure, establishing a stable mapping relationship between the output current and the input voltage. In actual operation, when the analog voltage output by the digital-to-analog converter module 207 changes, the voltage-to-current conversion circuit 206 will synchronously adjust the amplitude of its output current, thereby achieving continuous and adjustable control of the excitation current.

[0067] Furthermore, the voltage-to-current conversion circuit 206 has two output terminals. The first output terminal is connected to the positive terminal of the battery 101 via a first branch line, and the second output terminal is connected to the negative terminal of the battery 101 via a second branch line. Through this connection method, the excitation current can form a closed loop between the positive and negative terminals of the battery 101 and stably act on the battery under test 101. This structure not only ensures the clarity of the current path but also reduces unnecessary energy loss, making the output current more stable and reliable.

[0068] Throughout the control process, the microcontroller 104, acting as the core control unit, generates digital control signals based on pre-set algorithms or real-time calculation results and continuously outputs them to the digital-to-analog converter module 207. As the test progresses, the microcontroller 104 continuously updates the target excitation current value and synchronously adjusts the output digital control quantity, thereby driving the digital-to-analog converter module 207 and the voltage-to-current conversion circuit 206 to dynamically adjust the output current. Utilizing this "digital control-analog conversion-current output" link structure, the excitation current can precisely respond to changes in the state of the battery 101, achieving a gradual adjustment process that approximates the self-discharge current of the battery 101.

[0069] Furthermore, due to the hierarchical structure of the digital-to-analog conversion module 207 and the voltage-to-current conversion circuit 206, a clear interface relationship can be established between digital control and analog execution, enabling the system to have both the flexibility of digital control and the continuity of analog current output, thereby improving the overall control accuracy and system stability.

[0070] This embodiment constructs a hierarchical control structure of "microcontroller 104 - digital-to-analog converter module 207 - voltage-to-current conversion circuit 206", which enables the target excitation current to be accurately mapped from a digital signal to a stable analog current output, thereby achieving fine adjustment of the current applied to the battery 101. This not only improves the resolution and control accuracy of small current output, but also enhances the stability and responsiveness of the system, providing reliable support for high-precision measurement of self-discharge current.

[0071] As one implementation method, such as Figure 3 As shown, the voltage acquisition circuit 102 includes: The first filter circuit 201 has a first input terminal connected to the positive terminal of the battery 101 via a third branch line, and a second input terminal connected to the negative terminal of the battery 101 via a fourth branch line. The input terminal of the first analog-to-digital driver circuit 202 is connected to the output terminal of the first filter circuit 201; The analog-to-digital converter module 203 has its first input terminal connected to the output terminal of the first analog-to-digital driver circuit 202, and its output terminal connected to the input terminal of the microcontroller 104. The first filter circuit 201 is used to filter the voltage signal across the battery 101 to reduce noise interference. The first analog-to-digital driver circuit 202 is used to buffer and amplify the filtered voltage signal to match the input range of the analog-to-digital conversion module 203; The analog-to-digital converter module 203 is used to convert voltage signals into digital signals and send them to the microcontroller 104.

[0072] The voltage acquisition circuit 102 is used to acquire the voltage information at both ends of the battery 101 under test. Its overall structure includes a first filter circuit 201, a first analog-to-digital drive circuit 202, and an analog-to-digital conversion module 203. The components are connected in sequence to realize the complete processing from analog signal acquisition to digital signal output.

[0073] In this circuit, the first input terminal of the first filter circuit 201 is connected to the positive terminal of the battery 101 via a third branch, and the second input terminal is connected to the negative terminal of the battery 101 via a fourth branch, for directly acquiring the original voltage signal across the battery 101. This filter circuit can employ a low-pass filter structure to suppress high-frequency noise components in the voltage across the battery 101, thereby reducing the impact of external electromagnetic interference, circuit switching noise, and other factors on the measurement results. By performing preliminary processing on the original signal, subsequent circuits can receive a more stable voltage signal, improving the overall reliability of the measurement.

[0074] The primary function of the first analog-to-digital (ADC) driver circuit 202 is to further condition the filtered voltage signal. Specifically, this circuit buffers the signal to prevent the downstream load from affecting the upstream circuit, and also appropriately amplifies or scales the signal amplitude to keep it within the optimal input range of the ADC module 203. This step improves the signal's driving capability and ensures that the voltage signal possesses good linearity and stability before entering the ADC module 203.

[0075] The analog-to-digital converter (ADC) 203 receives the conditioned analog voltage signal and converts it into a corresponding digital quantity. This digital signal is then transmitted to the microcontroller 104 for subsequent calculations and control. By introducing the ADC 203, continuously changing voltage information can be converted into discrete data that the microcontroller 104 can process, thereby enabling real-time monitoring and analysis of voltage changes in the battery 101.

[0076] In actual operation, the voltage signal across the battery 101 is first introduced into the first filter circuit 201 for noise suppression via the third and fourth branches. The processed signal is then sent to the first analog-to-digital drive circuit 202 for buffering and amplitude matching. Subsequently, the analog-to-digital conversion module 203 completes the analog-to-digital conversion and outputs the result to the microcontroller 104. Based on the received digital voltage data and a preset algorithm, the microcontroller 104 analyzes the state of the battery 101 and controls the output of the excitation current circuit 103 accordingly to realize the measurement process of the self-discharge current.

[0077] Furthermore, since the voltage acquisition circuit (third branch and fourth branch) and the excitation current circuit (first branch and second branch) can be set up independently, a measurement structure similar to a four-wire system can be formed, which can effectively reduce the influence of wire resistance and contact resistance on voltage measurement results and improve measurement accuracy, especially suitable for detection scenarios with minute voltage changes.

[0078] This embodiment, by setting up a three-level processing structure of filtering, driving and analog-to-digital conversion, ensures that the voltage signal at the battery 101 terminal is adequately noise-suppressed and amplitude-matched before entering the microcontroller 104, thereby improving the accuracy and stability of voltage acquisition. At the same time, combined with the structural design of independent voltage acquisition circuit and current circuit, the measurement error caused by wire resistance is effectively reduced, improving the reliability and measurement accuracy of the overall test device in weak signal detection.

[0079] As one implementation method, such as Figure 3 As shown, the self-discharge current testing device also includes: The second filter circuit 204 has its input terminal connected to the output terminal of the voltage-to-current conversion circuit. The second analog-to-digital driver circuit 205 has its input terminal connected to the output terminal of the first analog-to-digital driver circuit 202, and its output terminal connected to the second input terminal of the analog-to-digital converter module 203. The second filter circuit 204 is used to filter the excitation current signal to reduce noise interference; The second analog-to-digital drive circuit 205 is used to buffer and adjust the amplitude of the filtered excitation current signal to match the input range of the analog-to-digital conversion module 203; The analog-to-digital conversion module 203 is used to perform analog-to-digital conversion on the excitation current signal and send the corresponding digital signal to the microcontroller 104 so that the microcontroller 104 can monitor or calibrate the excitation current.

[0080] The self-discharge current testing device may also include a signal acquisition link for excitation current detection, which mainly consists of a second filter circuit 204, a second analog-to-digital drive circuit 205, and a second input channel of an analog-to-digital conversion module 203. It is used to acquire the detection signal corresponding to the excitation current and feed it back to the microcontroller 104 for analysis and processing.

[0081] The second filter circuit 204 is used to acquire a detection signal related to the excitation current. This detection signal can be a voltage signal proportional to the output current, for example, obtained through a sampling resistor or an internal detection node. The second filter circuit 204 is used to filter this signal to reduce high-frequency noise and switching disturbances generated during the operation of the current source, thereby making the detection signal smoother and more stable, providing a reliable input for subsequent processing.

[0082] The main function of the second analog-to-digital driver circuit 205 is to further condition the filtered signal. Specifically, this circuit can isolate and buffer the signal to improve its driving capability. It can also adjust the signal amplitude according to the input requirements of the analog-to-digital converter module 203, ensuring it falls within the effective range of the module. This process avoids the adverse effects of excessively small or large signal amplitude on conversion accuracy, thus guaranteeing the effectiveness of data acquisition.

[0083] The analog-to-digital converter module 203 has at least two input channels, with the second input terminal connected to the output terminal of the second analog-to-digital drive circuit 205 to receive the conditioned excitation current detection signal. The analog-to-digital converter module 203 converts this analog signal into a corresponding digital quantity and transmits the conversion result to the microcontroller 104. In this way, the microcontroller 104 can not only acquire the battery 101 terminal voltage information but also simultaneously obtain excitation current-related detection data, thereby achieving real-time monitoring of the current output status.

[0084] During operation, while the excitation current circuit 103 supplies current to the battery 101, the detection signal on its output side undergoes noise suppression processing by the second filter circuit 204, signal conditioning by the second analog-to-digital driver circuit 205, and then input to the analog-to-digital conversion module 203 for analog-to-digital conversion. Based on the received digital signal, the microcontroller 104 can analyze the actual output of the current excitation current, such as determining whether it matches the target excitation current, or for subsequent calibration processing. With this detection link, the system can acquire feedback information while performing current regulation, thereby improving the overall control accuracy and reliability.

[0085] It should be noted that the input terminal of the second analog-to-digital driver circuit 205 should be connected to the output terminal of the second filter circuit 204 to form a complete signal transmission path, thereby ensuring the logical consistency of the detection link and the continuity of signal processing.

[0086] This embodiment adds a detection link to the excitation current output path, enabling the system to acquire and digitize the actual output excitation current in real time and feed this information back to the microcontroller 104, thereby realizing the monitoring and calibration of the current output status. This structure not only improves the accuracy of excitation current control, but also enhances the system's closed-loop regulation capability and anti-interference performance, which helps to improve the reliability and consistency of self-discharge current measurement results.

[0087] As one implementation method, such as Figure 3 As shown, the self-discharge current testing device also includes: The voltage reference providing module 210 is connected to the digital-to-analog converter module and the analog-to-digital converter module respectively, and is used to provide a reference voltage to the digital-to-analog converter module and the analog-to-digital converter module.

[0088] The self-discharge current testing device may also include a voltage reference providing module 210, which provides a stable reference voltage signal for the conversion circuit, thereby ensuring the accuracy and consistency of the signal conversion process.

[0089] Specifically, the voltage reference providing module 210 can be implemented using a high-precision reference source circuit, such as a bandgap reference circuit or a dedicated reference chip. Its output reference voltage features low temperature drift, high stability, and low noise. The reference voltage output by this module can serve as a unified reference standard for the conversion between analog and digital quantities in the system, providing a reliable reference basis for subsequent calculations and control.

[0090] In the digital-to-analog conversion path, the voltage reference module 210 provides a reference voltage to the digital-to-analog conversion module to determine the output range and resolution accuracy of the digital-to-analog conversion. Specifically, when the digital control signal output by the microcontroller 104 is converted into an analog voltage, the output voltage of the digital-to-analog conversion module is typically proportional to the reference voltage. By introducing a stable reference voltage, the analog control signal output by the digital-to-analog conversion module can have good linearity and consistency, thereby ensuring that the excitation current generated by the voltage-to-current conversion circuit can accurately reflect the target value.

[0091] In the analog-to-digital conversion path, the voltage reference providing module 210 also provides a reference voltage to the analog-to-digital conversion module to determine the quantization reference of the input analog signal. When sampling and quantizing the input voltage signal, the analog-to-digital conversion module uses this reference voltage as the full-scale reference, thereby mapping the continuously changing analog signal into the corresponding digital quantity. With the help of a stable reference voltage, quantization errors caused by reference fluctuations can be effectively reduced, improving the conversion accuracy of the voltage acquisition signal and the excitation current detection signal.

[0092] During actual operation, the voltage reference module 210 continuously outputs a reference voltage to the digital-to-analog converter module and the analog-to-digital converter module, ensuring that all analog-to-digital conversion processes in the system are based on a unified reference standard. This not only guarantees the consistency between the excitation current control link and the signal acquisition link but also reduces the impact of environmental temperature changes, power supply fluctuations, and other factors on the measurement results. By using a unified reference, the system can maintain good repeatability and stability under different operating conditions.

[0093] Furthermore, since the digital-to-analog conversion module and the analog-to-digital conversion module share the same reference voltage source, systematic errors caused by deviations between different reference sources can be avoided, thereby improving the overall coordination and accuracy of the measurement system.

[0094] This embodiment provides a unified and stable reference voltage for the digital-to-analog conversion module and the analog-to-digital conversion module by setting a voltage reference providing module 210. This ensures that the output control of the excitation current and the acquisition and conversion of voltage and current signals are all based on a consistent reference system, thereby effectively reducing the impact of reference drift and power fluctuations on the measurement results and improving the system's conversion accuracy, data consistency, and long-term operational stability.

[0095] As one implementation, the self-discharge current testing device further includes: a reference detection branch, which is connected to the voltage reference providing module and is used to acquire the reference signal output by the voltage reference providing module and generate reference detection data; The microcontroller is also configured to correct the battery's self-discharge current test results based on the deviation between the reference detection data and the reference signal.

[0096] The self-discharge current testing device also includes a reference detection branch connected to the voltage reference providing module 210. This branch receives the reference signal output by the voltage reference providing module 210 and processes it to generate corresponding reference detection data. Specifically, the voltage reference providing module 210 outputs a stable and known standard reference voltage or reference current signal. The reference detection branch samples this standard reference signal and completes signal conditioning and data conversion through a signal processing link similar to or the same as the battery detection path, thereby obtaining reference detection data reflecting the current operating state of the detection link. After acquiring the reference detection data, the microcontroller 104 compares it with the theoretical reference signal to determine the sampling error, conversion error, or device drift error of the detection system under the current operating state, and compensates and corrects the battery's self-discharge current test results based on these errors. In other words, when there is a deviation between the reference detection data and the theoretical reference signal, the microcontroller 104 can determine that there is a systematic error in the current detection link and calibrate the finally measured self-discharge current based on the deviation to reduce measurement offset during the test. By setting a reference detection branch, the system's detection accuracy can be monitored in real time during the test, and the test results can be dynamically corrected.

[0097] This embodiment sets up a reference detection branch connected to the voltage reference providing module 210, enabling the system to use a stable reference signal to verify the sampling and conversion errors of the detection link in real time, and to compensate and correct the battery self-discharge current test results based on the verification results, thereby improving the accuracy, consistency and long-term stability of self-discharge current measurement, while reducing the impact of device drift and environmental changes on the test results.

[0098] Furthermore, the temperature acquisition circuit 105 includes a temperature sensor 208 and a temperature acquisition module 209. The temperature sensor 208 is located near the battery, and the output terminal of the temperature sensor 208 is connected to the temperature acquisition module 209. The temperature acquisition module 209 is connected to the microcontroller 104.

[0099] The temperature sensor 208 is positioned near the battery to sense temperature changes around or within the battery itself. By placing the temperature sensor near the battery, the actual thermal state of the battery during testing can be more accurately reflected, thereby improving the representativeness of the temperature measurement data. The temperature sensor can be a thermistor, a digital temperature sensor, or other suitable device for measuring battery temperature, and its output terminal provides an electrical signal corresponding to the temperature.

[0100] The temperature acquisition module 209 is used to process the signal output by the temperature sensor. Specifically, the temperature acquisition module can amplify, filter, or linearize the input temperature signal to improve signal quality and convert it into a signal format suitable for the controller to read. For example, when the temperature sensor outputs an analog voltage signal, the temperature acquisition module may include an analog-to-digital converter to convert the analog signal into a digital quantity; when the temperature sensor outputs a digital signal, the temperature acquisition module can process and transmit the data.

[0101] The temperature acquisition module 209 is connected to the microcontroller 104 to transmit the processed temperature data to the controller. Upon receiving the temperature information, the controller combines it with the voltage acquisition data for subsequent current calculations or temperature compensation. Through this connection, the controller can monitor the battery's temperature changes in real time during testing and adjust relevant control strategies accordingly, resulting in more accurate test results.

[0102] During actual operation, the temperature sensor 208 continuously senses the temperature changes of the battery and outputs a corresponding electrical signal. This signal is processed by the temperature acquisition module 209 and then transmitted to the microcontroller 104. Based on the received temperature data, the controller can perform a comprehensive analysis of the battery status, such as correcting errors caused by voltage changes or participating in the calculation of the target excitation current, thereby improving the accuracy of the testing process.

[0103] This embodiment places a temperature sensor near the battery and processes the temperature signal in conjunction with a temperature acquisition module, enabling the controller to acquire real-time information on battery temperature changes. This allows the temperature factor to be incorporated into the self-discharge current calculation process for compensation, reducing the impact of temperature fluctuations on the measurement results and improving test accuracy, data reliability, and the system's environmental adaptability.

[0104] Furthermore, the microcontroller 104 is also connected to the signal isolation module 211, which is connected to the host computer 212.

[0105] Specifically, the microcontroller 104, while performing functions such as voltage acquisition, temperature acquisition, and excitation current control, is also responsible for organizing the data acquired during the test and outputting it to the signal isolation module 211 through the communication interface. The output data may include battery terminal voltage information, temperature information, excitation current data, and calculated self-discharge current results, etc.

[0106] The signal isolation module 211 is located between the microcontroller 104 and the host computer 212, and its main function is to isolate communication signals. This module can be implemented using opto-isolators, digital isolators, or isolated communication interfaces, making the controller-side circuitry and the host computer-side circuitry electrically independent. This isolation structure prevents voltage fluctuations, ground potential differences, or electromagnetic interference from the host computer from being conducted into the testing device, thus avoiding any impact on the precision measurement circuitry. Simultaneously, this module can also perform signal shaping or buffering to ensure stable transmission of communication data.

[0107] The host computer 212 receives data from the signal isolation module 211 and displays, stores, or further analyzes the data. For example, the host computer can visualize test results or compare and analyze test data from different time periods, thus providing users with a more intuitive reference. Furthermore, the host computer can send control commands to the microcontroller, such as starting the test, stopping the test, or adjusting parameters, to achieve remote control of the testing process.

[0108] In actual operation, the microcontroller 104 transmits the collected and calculated data to the host computer 212 through the signal isolation module 211. The host computer processes and displays the received data. At the same time, the host computer can also send commands to the microcontroller through the signal isolation module, thus forming a two-way communication path. With this structure, both data interaction functionality and electrical safety between different parts of the system are achieved.

[0109] This implementation method sets up a signal isolation module between the microcontroller and the host computer to electrically isolate the data communication process from the measurement circuit, thereby effectively suppressing the influence of external interference and ground potential difference on the test system, improving the stability of data transmission and the reliability of measurement results, and enhancing the system's security and anti-interference capabilities.

[0110] Example 2 This second embodiment provides a testing method based on the battery self-discharge current testing device provided in the first embodiment. The testing method includes: Step S101. At the start of the test, control the output current of the excitation current circuit to be zero, and obtain the initial voltage of the battery through the voltage acquisition circuit; Step S102. During the test, the real-time voltage of the battery is acquired through the voltage acquisition circuit, and the first target excitation current is obtained based on the initial voltage and the real-time voltage; Step S103. Control the excitation current circuit to output an excitation current corresponding to the first target excitation current until the battery voltage remains stable, and then determine the current excitation current as the battery's self-discharge current.

[0111] In step S101, upon test startup, the microcontroller first controls the excitation current circuit to a zero-output state, allowing the battery to enter the initial detection phase without external compensation current. In this state, the voltage acquisition circuit acquires the voltage across the battery terminals and records the obtained voltage value as the initial voltage. This initial voltage reflects the battery's electrical state when unaffected by external current interference and can serve as a reference for subsequent calculations.

[0112] In step S102, during the ongoing test, the voltage acquisition circuit detects the battery terminal voltage at a preset sampling period and transmits the real-time voltage data to the microcontroller. The microcontroller compares the acquired initial voltage with the current real-time voltage to obtain the voltage change, and converts this change into a corresponding first target excitation current according to a pre-set calculation relationship. This target current reflects the current required to compensate for voltage changes under the current battery condition.

[0113] In step S103, the microcontroller generates a corresponding control signal based on the calculated first target excitation current and outputs it to the excitation current circuit, causing it to generate an excitation current corresponding to the target value and apply this current to the battery terminals. During the test, the microcontroller continuously repeats the voltage acquisition and current calculation process and continuously updates the output value of the excitation current, gradually adjusting it to approach the battery's own self-discharge current. When the battery terminal voltage is detected to remain essentially constant over a period of time, it can be considered that the applied excitation current has effectively compensated for the voltage drop caused by the battery's self-discharge, and the corresponding excitation current is then determined as the battery's self-discharge current.

[0114] Through the above steps, this embodiment transforms the self-discharge current, which is difficult to measure directly, into a process of adjusting the controllable excitation current, and determines the final result through the voltage stability criterion, thereby completing the test of the battery's self-discharge characteristics.

[0115] This implementation method establishes a dynamic adjustment process for the excitation current based on voltage changes, so that the excitation current gradually approaches the battery self-discharge current. With voltage stability as the criterion, it achieves the goal of obtaining test results without directly detecting minute currents, thereby improving the feasibility, accuracy and stability of the measurement, while simplifying the implementation process of the test method.

[0116] Example 3 This embodiment three provides a test method based on the battery self-discharge current test device provided in embodiment one. The test method includes: Step S201. At the start of the test, control the output current of the excitation current circuit to be zero, and obtain the initial voltage of the battery through the voltage acquisition circuit and the initial temperature of the battery through the temperature acquisition circuit. Step S202. During the test, the real-time voltage of the battery is acquired through the voltage acquisition circuit, and the real-time temperature of the battery is acquired through the temperature acquisition circuit. The second target excitation current is obtained based on the initial voltage, real-time voltage, initial temperature and real-time temperature. Step S203. Control the excitation current circuit to output an excitation current corresponding to the second target excitation current until the battery voltage remains stable, and then determine the current excitation current as the battery's self-discharge current.

[0117] In step S201, at the start of the test, the microcontroller first controls the excitation current circuit to a zero-current output state, allowing the battery under test to enter the initial measurement state without applying external compensation current. During this stage, the voltage acquisition circuit detects the voltage across the battery terminals to obtain initial voltage information; simultaneously, the temperature acquisition circuit measures the battery temperature to obtain initial temperature data. The initial voltage reflects the battery's electrical state without external current, and the initial temperature characterizes the thermal environment at the start of the test; both serve as reference parameters for subsequent calculations.

[0118] In step S202, during the continuous testing, the voltage acquisition circuit acquires the battery's current voltage value according to a preset sampling frequency, and the temperature acquisition circuit simultaneously detects the battery's temperature change at the corresponding moment. The microcontroller receives the aforementioned real-time voltage and real-time temperature data. Subsequently, based on the difference between the initial voltage and the real-time voltage, and combined with the relationship between the initial temperature and the current temperature, the microcontroller performs a correction analysis on the change in battery terminal voltage. Since temperature changes may affect the battery's open-circuit voltage, by introducing temperature-related parameters to compensate for voltage changes, the voltage change component caused by self-discharge can be extracted more accurately. Based on this, the microcontroller calculates the second target excitation current according to the initial voltage, real-time voltage, initial temperature, and real-time temperature. This current is used to characterize the current magnitude required to compensate for the self-discharge effect in the current state.

[0119] In step S203, the microcontroller generates a corresponding control signal based on the second target excitation current and outputs it to the excitation current circuit, causing it to generate an excitation current corresponding to the target value and apply this current to the battery terminals. During the test, the microcontroller continuously updates real-time voltage and temperature data and constantly corrects the second target excitation current, so that the excitation current can dynamically respond to changes in the battery state. When it is detected that the battery terminal voltage remains basically stable within a certain time interval, it indicates that the applied excitation current has reached a balance with the battery's own self-discharge current. At this time, the currently output excitation current can be determined as the battery's self-discharge current.

[0120] Through the above steps, this embodiment introduces a temperature compensation mechanism during the current regulation process, making the calculation of the excitation current closer to the actual working state of the battery, thereby improving the accuracy of the test results.

[0121] This embodiment introduces a temperature parameter during the self-discharge current test to compensate for voltage changes, thereby effectively eliminating the influence of temperature fluctuations in the calculation results of the excitation current. This improves the accuracy and stability of the self-discharge current measurement and enhances the adaptability and reliability of the test method under different environmental conditions.

[0122] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A self-discharge current testing apparatus of a battery, characterized by, The self-discharge current testing device comprises: a voltage acquisition circuit connected with the battery; an excitation current circuit electrically connected with the battery; a microcontroller connected with the voltage acquisition circuit and the excitation current circuit respectively; the microcontroller is configured to control the output current of the excitation current circuit to be zero at the beginning of the test, and acquire the initial voltage of the battery through the voltage acquisition circuit; during the test, the real-time voltage of the battery is acquired through the voltage acquisition circuit, the first target excitation current is acquired according to the initial voltage and the real-time voltage, and the excitation current corresponding to the first target excitation current is output by the excitation current circuit until the voltage of the battery remains stable, and the current excitation current is determined as the self-discharge current of the battery.

2. The self-discharging current test apparatus of claim 1, wherein The microcontroller calculates the first target excitation current I according to the following formula t1 : I t1 = (U0 - U t ) / R; where U0 is the initial voltage, U is the real-time voltage, and R is the equivalent impedance of the circuit. t where U0 is the initial voltage, U is the real-time voltage, and R is the equivalent impedance of the circuit.

3. The self-discharge current test apparatus of claim 1, wherein the microcontroller is configured to control the excitation current circuit to gradually adjust the output excitation current according to a preset adjustment step, so that the output excitation current gradually approaches the first target excitation current; after each adjustment, the voltage variation trend of the battery is detected; when the voltage variation direction is detected to be reversed, the adjustment step is reduced, and the output excitation current is adjusted again; until the adjustment step is less than a preset threshold, the current excitation current is determined as the self-discharge current of the battery.

4. The self-discharging current test apparatus of claim 1, wherein The self-discharge current testing device further comprises: a temperature acquisition circuit connected with the battery and the microcontroller respectively; the microcontroller is further configured to control the output current of the excitation current circuit to be zero at the beginning of the test, acquire the initial voltage of the battery through the voltage acquisition circuit, and acquire the initial temperature of the battery through the temperature acquisition circuit; during the test, the real-time voltage of the battery is acquired through the voltage acquisition circuit, and the real-time temperature of the battery is acquired through the temperature acquisition circuit, the second target excitation current is acquired according to the initial voltage, the real-time voltage, the initial temperature and the real-time temperature, and the excitation current corresponding to the second target excitation current is output by the excitation current circuit until the voltage of the battery remains stable, and the current excitation current is determined as the self-discharge current of the battery.

5. The self-discharging current test apparatus of claim 4, wherein, The microcontroller calculates the second target excitation current I according to the following formula t2 : I t2 = (U0 - (U t - (T0 - T t )*k)) / R; Where U0 is the initial voltage, U t T is the real-time voltage, T0 is the initial temperature, and T t R is the real-time temperature, R is the equivalent impedance of the circuit, and k is the temperature coefficient of the battery.

6. The self-discharge current test apparatus according to any one of claims 1 to 5, wherein The excitation current circuit comprises: a digital-to-analog conversion module, the input end of the digital-to-analog conversion module is connected with the output end of the microcontroller; a voltage-current conversion circuit, the input end of the voltage-current conversion circuit is connected with the output end of the digital-to-analog conversion module, the first output end of the voltage-current conversion circuit is connected with the positive electrode of the battery through a first branch line, and the second output end of the voltage-current conversion circuit is connected with the negative electrode of the battery through a second branch line; the microcontroller is configured to output a digital control signal to the digital-to-analog conversion module, and the digital control signal is converted into an analog voltage signal by the digital-to-analog conversion module and then input to the voltage-current conversion circuit, so as to control the voltage-current conversion circuit to output the corresponding excitation current.

7. The self-discharging current test apparatus of claim 6, wherein, The voltage acquisition circuit comprises: a first filter circuit, a first input terminal of the first filter circuit being connected to a positive electrode of the battery through a third branch line, and a second input terminal of the first filter circuit being connected to a negative electrode of the battery through a fourth branch line; a first analog-digital driving circuit, an input terminal of the first analog-digital driving circuit being connected to an output terminal of the first filter circuit; an analog-digital conversion module, a first input terminal of the analog-digital conversion module being connected to an output terminal of the first analog-digital driving circuit, and an output terminal of the analog-digital conversion module being connected to an input terminal of the microcontroller; the first filter circuit is configured to filter a voltage signal between the battery to reduce noise interference; the first analog-digital driving circuit is configured to buffer and amplify the filtered voltage signal to match an input range of the analog-digital conversion module; the analog-digital conversion module is configured to convert the voltage signal into a digital signal and send the digital signal to the microcontroller.

8. The self-discharging current test apparatus of claim 7, wherein, The self-discharge current testing device further comprises: a second filter circuit, an input terminal of the second filter circuit being connected to an output terminal of the voltage-current conversion circuit; a second analog-digital driving circuit, an input terminal of the second analog-digital driving circuit being connected to an output terminal of the first filter circuit, and an output terminal of the second analog-digital driving circuit being connected to a second input terminal of the analog-digital conversion module; the second filter circuit is configured to filter the excitation current signal to reduce noise interference; the second analog-digital driving circuit is configured to buffer and amplitude adjust the filtered excitation current signal to match an input range of the analog-digital conversion module; the analog-digital conversion module is configured to perform analog-digital conversion on the excitation current signal, and send a corresponding digital signal to the microcontroller, so that the microcontroller monitors or calibrates the excitation current.

9. A test method for a self-discharge current test device based on the battery according to claim 1, characterized by, The testing method comprises: controlling the excitation current circuit to output zero at the beginning of the test, and acquiring an initial voltage of the battery through the voltage acquisition circuit; acquiring a real-time voltage of the battery through the voltage acquisition circuit during the test, and acquiring a first target excitation current according to the initial voltage and the real-time voltage; controlling the excitation current circuit to output an excitation current corresponding to the first target excitation current, and determining a current excitation current as the self-discharge current of the battery when the voltage of the battery remains stable.

10. A test method for a self-discharge current test device for a battery according to claim 3, characterized by, The testing method comprises: controlling the excitation current circuit to output zero at the beginning of the test, and acquiring an initial voltage of the battery through the voltage acquisition circuit, and acquiring an initial temperature of the battery through the temperature acquisition circuit; acquiring a real-time voltage of the battery through the voltage acquisition circuit during the test, and acquiring a real-time temperature of the battery through the temperature acquisition circuit, and acquiring a second target excitation current according to the initial voltage, the real-time voltage, the initial temperature and the real-time temperature; controlling the excitation current circuit to output an excitation current corresponding to the second target excitation current, and determining a current excitation current as the self-discharge current of the battery when the voltage of the battery remains stable.

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