A battery leakage current detection system and method

Abstract

A battery leakage current detection system and method, the method comprising: disconnecting a constant voltage control unit from a battery and switching the constant voltage control unit to a minimum current range; calculating the output full scale ratio N required by PMW_DAC, so that when the PMW_DAC output full scale ratio is N, the constant voltage given signal is infinitely close to and less than the battery voltage, and the output full scale ratio N of the PMW_DAC is locked; connecting the constant voltage control unit with the battery to make the constant voltage control unit start working and charge the battery; monitoring the output current of the constant voltage control unit through a current detection unit, and adjusting the current range of the constant voltage control unit in real time based on the monitored output current, when the output current is stable at a certain value of a certain current range, the value is the leakage current of the battery. The present application can quickly and accurately test the leakage current of the battery or capacitor.

Description

Technical Field

[0001] This invention relates to the field of battery leakage current detection, specifically to a battery leakage current detection system and method. Background Technology

[0002] Due to inherent limitations in the working principle of batteries and capacitors, differences in manufacturing processes, or limitations in raw material technology, all manufactured batteries and capacitors inevitably possess a certain amount of leakage current. This leakage current leads to energy loss during long-term storage. Leakage current testing is necessary before batteries are shipped, serving as a partial reference for battery classification. At the battery's end-user level, the leakage current level of the batteries also needs to be classified (for example, when batteries are used in parallel, batteries with the same leakage current level should be selected; otherwise, a battery with a high leakage current will leak the entire battery pack's storage capacity).

[0003] The common method used by battery manufacturers to detect battery leakage current is to leave the battery at room temperature for a period of time, usually one to two weeks, and sometimes up to a month or even longer, and then test the voltage change during this period to estimate the leakage current. This method has two obvious drawbacks: 1. The test time is long; 2. The accuracy of the measured leakage current is very low.

[0004] In addition, the invention disclosed in 201911108946.9, "A Method for Detecting Leakage Current of a Lithium Battery," describes a leakage current detection method that uses a given trial charging current to observe the slope of a time-voltage curve over a period of time, and then adjusts the charging current accordingly. When the slope reaches 0, the charging current at that moment is taken as the battery's leakage current. However, this method is slow (adjustment can only be made after the slope of the time-voltage curve is obtained), does not explain how to eliminate the influence of temperature (temperature directly affects the battery voltage, thus interfering with the slope of the time-voltage curve; therefore, this method relies on a good constant temperature environment), and does not explain the essential principle of leakage current testing. Summary of the Invention

[0005] In view of the technical defects and drawbacks existing in the prior art, embodiments of the present invention provide a battery leakage current detection system and method to overcome the above problems or at least partially solve the above problems, the specific solution of which is as follows:

[0006] As a first aspect of the present invention, a battery leakage current detection system is provided. The system includes a PMW_DAC, a constant voltage control unit, a current detection unit, a difference detection unit, a battery, and a processor. The input terminal of the PMW_DAC is electrically connected to a reference voltage source, and the output terminal is electrically connected to the input terminals of the constant voltage control unit and the difference detection unit, respectively. The output terminal of the constant voltage control unit is electrically connected to the battery and the current detection unit, respectively. The processor is electrically connected to the core PMW_DAC, the current detection unit, and the difference detection unit, respectively.

[0007] The PMW_DAC is used to connect to the reference voltage source and outputs the processed signal as a constant voltage setpoint signal to the constant voltage control unit.

[0008] The constant voltage control unit is used to determine the charging voltage to be output to the battery based on the constant voltage given signal, and to charge the battery; for example, if the constant voltage given signal of the adding current output is 0.05V, the constant voltage control unit will charge the battery with a voltage of 0.05V. The constant voltage control unit is a negative feedback control loop: the output of the adding circuit is used as the given signal, and the battery voltage is used as the feedback control signal.

[0009] The difference detection unit is used to monitor the difference between the constant voltage given signal output by the PMW_DAC and the battery voltage;

[0010] The current detection unit is used to monitor the magnitude of the current output by the constant voltage control unit;

[0011] The processor is used to control the output of the PMW_DAC, and monitors the difference between the constant voltage setpoint signal output by the PMW_DAC and the battery voltage through the difference detection unit, and monitors the current output by the constant voltage control unit through the current detection unit.

[0012] Furthermore, the system also includes a reference signal unit and a low-noise processing unit. The reference signal unit is used to provide a reference voltage source for the PMW_DAC, and the low-noise processing unit is used to perform noise reduction processing on the reference voltage source output to the PMW_DAC. The reference signal unit is a high-precision low-temperature drift reference signal unit, and the constant voltage control unit is a multi-current range constant voltage control unit.

[0013] Furthermore, the processor is also used to calculate the required output full-scale ratio N of the PMW_DAC, such that when the output full-scale ratio of the PMW_DAC is N, the constant voltage given signal is infinitely close to and less than the battery voltage, and the output full-scale ratio N of the PMW_DAC is locked.

[0014] Furthermore, the specific calculation of the required output full-scale ratio N for PMW_DAC is as follows:

[0015] Disconnect the constant voltage control unit from the battery;

[0016] The PMW_DAC output is controlled to half full scale, and the full scale ratio N of the PMW_DAC output is found through a binary search algorithm. When the full scale ratio of the PMW_DAC output is N, the constant voltage command signal is closest to and less than the battery voltage, and the full scale ratio N of the PMW_DAC output is locked.

[0017] Furthermore, the constant voltage control unit only establishes a connection with the battery to charge the battery when the processor calculates and controls the full-scale ratio N of the core DAC unit and the full-scale ratio M of the auxiliary DAC unit. Specifically, the processor is used to monitor the output current of the constant voltage control unit through the current detection unit, and adjust the current range of the constant voltage control unit in real time based on the monitored output current. When the output current stabilizes at a certain value of a certain current range, this value is the leakage current of the battery.

[0018] Furthermore, the real-time adjustment of the current range of the constant voltage control unit based on the monitored output current specifically includes: switching to the minimum current range before charging the battery; during the charging process, when the output current exceeds a certain proportion of the full scale of the current range, gradually increasing the current range until the current is less than a certain proportion of the full scale of the current range, and then gradually decreasing the current range until the output current is as close as possible to the full scale of the current range.

[0019] As a second aspect of the present invention, a battery leakage current detection method is provided, the method comprising:

[0020] Step 1: Disconnect the constant voltage control unit from the battery and switch the constant voltage control unit to the minimum current range;

[0021] Step 2: Calculate the required output full-scale ratio N of PMW_DAC, so that when the output full-scale ratio of PMW_DAC is N, the constant voltage given signal is infinitely close to and less than the battery voltage, and lock the output full-scale ratio N of PMW_DAC.

[0022] Step 3: Connect the constant voltage control unit to the battery to start the constant voltage control unit and charge the battery.

[0023] Step 4: Monitor the output current of the constant voltage control unit through the current detection unit, and adjust the current range of the constant voltage control unit in real time based on the monitored output current. When the output current stabilizes at a certain value of a certain current range, this value is the leakage current of the battery.

[0024] Furthermore, in step 2, calculating the required output full-scale ratio N for PMW_DAC specifically includes:

[0025] The PMW_DAC output is controlled to half full scale, and the full scale ratio N of the PMW_DAC output is found through a binary search algorithm. When the full scale ratio of the PMW_DAC output is N, the constant voltage command signal is closest to and less than the battery voltage, and the full scale ratio N of the PMW_DAC output is locked.

[0026] Furthermore, the real-time adjustment of the current range of the constant voltage control unit based on the monitored output current specifically includes: switching to the minimum current range before charging the battery; during the charging process, when the output current exceeds a certain proportion of the full scale of the current range, gradually increasing the current range until the current is less than a certain proportion of the full scale of the current range, and then gradually decreasing the current range until the output current is as close as possible to the full scale of the current range.

[0027] The present invention has the following beneficial effects:

[0028] This invention reduces the circuit's temperature sensitivity by using a high-precision, low-temperature drift reference, making it unaffected by temperature. It calculates the required full-scale output ratio N for the PMW_DAC, ensuring that when the PMW_DAC's full-scale output ratio is N, the constant voltage input signal is infinitely close to and less than the battery voltage, thus locking the PMW_DAC's full-scale output ratio N. Then, the constant voltage control unit is electrically connected to the battery, activating it. A current detection unit monitors the output current of the constant voltage control unit, and the current range of the control unit is adjusted in real time based on the monitored output current. When the output current stabilizes at a specific value within a certain current range, this value represents the battery's leakage current, thereby enabling rapid and accurate testing of the battery or capacitor's leakage current. Attached Figure Description

[0029] Figure 1 This invention provides a battery leakage current detection system according to an embodiment of the invention.

[0030] Figure 2 The present invention provides a battery leakage current detection method. Detailed Implementation

[0031] 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 a part of the present invention, and not all of the embodiments. 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.

[0032] like Figure 1As shown, as a first embodiment of the present invention, a battery leakage current detection system is provided. The system includes a reference signal unit, a PMW_DAC, a low-noise processing unit, a constant voltage control unit, a current detection unit, a difference detection unit, a battery, and a processor. The reference signal unit is electrically connected to the input terminal of the PMW_DAC through the low-noise processing unit. The output terminal of the PMW_DAC is electrically connected to the input terminals of the constant voltage control unit and the difference detection unit, respectively. The output terminal of the constant voltage control unit is electrically connected to the battery and the current detection unit, respectively. The processor is electrically connected to the core PMW_DAC, the current detection unit, and the difference detection unit, respectively.

[0033] The reference signal unit is used to provide a reference voltage source for the PMW_DAC, and the low noise processing unit is used to perform noise reduction processing on the reference voltage source output to the PMW_DAC.

[0034] The PMW_DAC is used to connect to the reference voltage source and outputs the processed signal as a constant voltage setpoint signal to the constant voltage control unit.

[0035] The constant voltage control unit is used to determine the charging voltage to be output to the battery based on the constant voltage given signal, and to charge the battery; for example, if the constant voltage given signal of the added current output is 0.05V, the constant voltage control unit will charge the battery with a voltage of 0.05V. The constant voltage control unit is a negative feedback control loop, with the battery voltage as the feedback control signal.

[0036] The difference detection unit is used to monitor the difference between the constant voltage given signal output by the PMW_DAC and the battery voltage;

[0037] The current detection unit is used to monitor the magnitude of the current output by the constant voltage control unit;

[0038] The processor is used to control the output of the PMW_DAC, and monitors the difference between the constant voltage setpoint signal output by the PMW_DAC and the battery voltage through the difference detection unit, and monitors the current output by the constant voltage control unit through the current detection unit.

[0039] The constant voltage control unit is a multi-current range constant voltage control unit, and the reference signal unit is a high-precision low-temperature drift reference signal unit. By using a high-precision low-temperature drift reference, the circuit's sensitivity to temperature is reduced, making it unaffected by temperature.

[0040] Preferably, the present invention calculates the required output full-scale ratio N of PMW_DAC using a binary search algorithm, specifically including:

[0041] Disconnect the constant voltage control unit from the battery;

[0042] The PMW_DAC output is controlled to half full scale, and the full scale ratio N of the PMW_DAC output is found through a binary search algorithm. When the full scale ratio of the PMW_DAC output is N, the constant voltage command signal is closest to and less than the battery voltage, and the full scale ratio N of the PMW_DAC output is locked unchanged.

[0043] The binary search algorithm is an existing algorithm. Its basic idea is to compare the data at the middle position of the sequence to be searched with the element to be searched. If they are equal, the search is successful; otherwise, the sequence is divided into left and right parts based on that position. Next, based on the ascending / descending order of the sequence and the size relationship between the middle element and the search element, the part of the sequence where the search element might exist is selected, and the same method is used to search that part until it can be determined whether the search element exists.

[0044] This invention divides the full scale from 0 to 1 into several parts, such as 1 / 8 full scale, 1 / 4 full scale, 1 / 2 full scale, 3 / 4 full scale, 7 / 8 full scale, etc., and sorts the different full scales. Using 1 / 2 full scale as the middle element, the sequence is divided into left and right parts. First, the PMW_DAC is controlled to output 1 / 2 full scale, and the difference between the constant voltage setpoint signal and the battery is detected by the anomaly detection unit. If there is a certain difference between the constant voltage setpoint signal and the battery, the corresponding element is found in the left and right sequences of the middle element, i.e., 1 / 2 full scale, based on a binary search algorithm. For example... If the constant voltage given signal is less than the battery voltage, the full scale of the PMW_DAC output is corrected to the element to the right of the middle element, such as correcting the full scale of the PMW_DAC output to 3 / 4 of the full scale. If the constant voltage given signal is greater than the battery voltage, the full scale of the PMW_DAC output is corrected to the element to the left of the middle element, such as correcting the full scale of the core DAC output to 1 / 4 of the full scale. The search is performed based on a binary search algorithm until the constant voltage given signal is found to be closest to and less than the battery voltage. At this time, the full scale of the PMW_DAC corresponding to this point is the required full scale ratio N.

[0045] Preferably, the constant voltage control unit only establishes a connection with the battery to charge the battery when the processor calculates and controls the full-scale ratio N of the core DAC unit and the full-scale ratio M of the auxiliary DAC unit. Specifically, the processor monitors the output current of the constant voltage control unit through the current detection unit and adjusts the current range of the constant voltage control unit in real time based on the monitored output current. When the output current stabilizes at a certain value within a certain current range, this value is the leakage current of the battery.

[0046] Preferably, adjusting the current range of the constant voltage control unit in real time based on the monitored output current specifically includes: switching to the minimum current range before charging the battery; during the charging process, when the output current exceeds a certain percentage of the full scale of the current current range, gradually increasing the current range until the current is less than a certain percentage of the full scale of the current current range, and then gradually decreasing the current range until the output current is as close as possible to the full scale of the current current range.

[0047] As a second embodiment of the present invention, a battery leakage current detection method is provided, the method comprising:

[0048] Step 1: Disconnect the constant voltage control unit from the battery and switch the constant voltage control unit to the minimum current range;

[0049] Step 2: Provide a reference voltage source for PMW_DAC through a high-precision low-temperature drift reference signal unit, calculate the required output full-scale ratio N of PMW_DAC, so that when the output full-scale ratio of PMW_DAC is N, the constant voltage given signal is infinitely close to and less than the battery voltage, and lock the output full-scale ratio N of PMW_DAC.

[0050] Step 3: Connect the constant voltage control unit to the battery to start the constant voltage control unit and charge the battery.

[0051] Step 4: Monitor the output current of the constant voltage control unit through the current detection unit, and adjust the current range of the constant voltage control unit in real time based on the monitored output current. When the output current stabilizes at a certain value of a certain current range, this value is the leakage current of the battery.

[0052] In step 2, calculating the required output full-scale ratio N for PMW_DAC specifically includes:

[0053] The PMW_DAC output is controlled to half full scale, and the full scale ratio N of the PMW_DAC output is found through a binary search algorithm. When the full scale ratio of the PMW_DAC output is N, the constant voltage command signal is closest to and less than the battery voltage, and the full scale ratio N of the PMW_DAC output is locked.

[0054] Specifically, the real-time adjustment of the current range of the constant voltage control unit based on the monitored output current includes: switching to the minimum current range before charging the battery; during the charging process, when the output current exceeds a certain percentage of the full scale of the current range, gradually increasing the current range until the current is less than a certain percentage of the full scale of the current range, and then gradually decreasing the current range until the output current is as close as possible to the full scale of the current range.

[0055] It should be noted that the batteries of the present invention include, but are not limited to, button cells, pouch cells, cylindrical cells and aluminum-cased cells, and are not limited to, primary cells, secondary cells and energy storage capacitors.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A battery leakage current detection system, characterized by, The system comprises a PMW_DAC, a constant voltage control unit, a current detection unit, a difference detection unit, a battery and a processor, an input end of the PMW_DAC is electrically connected with a reference voltage source, output ends are electrically connected with input ends of the constant voltage control unit and the difference detection unit respectively, an output end of the constant voltage control unit is electrically connected with the battery and the current detection unit respectively, and the processor is electrically connected with the PMW_DAC, the current detection unit and the difference detection unit respectively. The PMW_DAC is used for accessing the reference voltage source and outputting a processed signal as a constant voltage given signal to the constant voltage control unit. The constant voltage control unit is used for determining a charging voltage needed to be output to the battery based on the constant voltage given signal and charging the battery. The difference detection unit is used for monitoring a difference between the constant voltage given signal output by the PMW_DAC and the battery voltage. The current detection unit is used for monitoring a current size output by the constant voltage control unit. The processor is used for controlling an output amount of the PMW_DAC, monitoring the difference between the constant voltage given signal output by the PMW_DAC and the battery voltage through the difference detection unit, and monitoring the current size output by the constant voltage control unit through the current detection unit. The constant voltage control unit establishes a connection with the battery to charge the battery only when the processor calculates and controls the output fullness ratio N of the PMW_DAC, and the processor is specifically used for monitoring an output current of the constant voltage control unit through the current detection unit and adjusting an output current range of the constant voltage control unit in real time based on the monitored output current size, wherein the value of the output current when the output current is stable at a certain value of a certain output current range is the leakage current of the battery. The constant voltage control unit establishes a connection with the battery to charge the battery only when the processor calculates and controls the output fullness ratio N of the PMW_DAC, and the processor is specifically used for monitoring an output current of the constant voltage control unit through the current detection unit and adjusting an output current range of the constant voltage control unit in real time based on the monitored output current size, wherein the value of the output current when the output current is stable at a certain value of a certain output current range is the leakage current of the battery.

2. The battery leakage current detection system of claim 1, wherein, The system further comprises a reference signal unit and a low-noise processing unit, the reference signal unit is used for providing the reference voltage source for the PMW_DAC, and the low-noise processing unit is used for performing noise reduction processing on the reference voltage source output to the PMW_DAC.

3. The battery leakage current detection system of claim 1, wherein, The processor is further used for calculating the output fullness ratio N needed by the PMW_DAC, so that the constant voltage given signal infinitely approaches and is less than the battery voltage when the output fullness ratio of the PMW_DAC is N, and the output fullness ratio N of the PMW_DAC is locked.

4. The battery leakage current detection system of claim 3, wherein, The output fullness ratio N needed by the PMW_DAC is specifically calculated as follows: The connection between the constant voltage control unit and the battery is disconnected. The output fullness ratio N of the PMW_DAC is found through a binary search algorithm, so that the constant voltage given signal most approaches and is less than the battery voltage when the output fullness ratio of the PMW_DAC is N, and the output fullness ratio N of the PMW_DAC is locked.

5. A battery leakage current detection method characterized by, The application discloses a battery leakage current detection system and a detection method thereof. Step 1, disconnect the constant voltage control unit from the battery, and switch the constant voltage control unit to the minimum current range; Step 2, calculate the output full scale ratio N required by the PMW_DAC, so that when the output full scale ratio of the PMW_DAC is N, the constant voltage given signal is infinitely close to and less than the battery voltage, and the output full scale ratio N of the PMW_DAC is locked; Step 3, connect the constant voltage control unit to the battery, and make the constant voltage control unit work to charge the battery; Step 4, monitor the output current of the constant voltage control unit through the current detection unit, and adjust the current range of the constant voltage control unit in real time based on the monitored output current, when the output current is stable at a certain value of a certain current range, the value is the leakage current of the battery.

6. The battery leakage current detection method according to claim 5, wherein In step 2, the calculation of the output full scale ratio N required by the PMW_DAC specifically includes: controlling the PMW_DAC to output 1 / 2 full scale, and finding the output full scale ratio N of the PMW_DAC through a dichotomy search algorithm, so that when the output full scale ratio of the PMW_DAC is N, the constant voltage given signal is infinitely close to and less than the battery voltage, and the output full scale ratio N of the PMW_DAC is locked.

7. The battery leakage current detection method of claim 5, wherein, Adjusting the current range of the constant voltage control unit in real time based on the monitored output current specifically includes: switching to the minimum current range before charging the battery, gradually increasing the current range when the output current exceeds a certain proportion of the full scale of the current range during the charging process, gradually reducing the current range when the current is less than a certain proportion of the full scale of the current range, and gradually increasing the output current to the maximum limit close to the full scale of the current range.

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