Method and device for detecting conversion efficiency of single battery

Abstract

The invention discloses a method and a device for detecting the conversion efficiency of a battery monomer, and belongs to the technical field of industrial detection. The method for detecting the conversion efficiency of the single battery comprises the following steps: under the condition that at least two light source devices work based on target illumination intensity, determining a first gray value of a calibration object in a to-be-detected image based on the to-be-detected image corresponding to the single battery and the calibration object acquired by an image sensor; determining the actual illumination intensity corresponding to the to-be-detected image based on the first gray value and the corresponding relationship between the image gray value and the illumination intensity; and calculating the conversion efficiency of the battery monomer based on the actual illumination intensity, the first gray value, the first open-circuit voltage of the calibration object under the target illumination intensity and the second gray value of the battery monomer in the to-be-detected image. The method for detecting the conversion efficiency of the single battery realizes the non-contact measurement of the conversion efficiency of the single battery, is suitable for the measurement of the single battery without a main grid, and is wide in application scene.

Description

Technical Field

[0001] The present application belongs to the field of industrial detection technology, and in particular, relates to a method and device for detecting conversion efficiency of a battery cell. Background Art

[0002] In order to improve the overall performance and economic benefits of solar power generation systems, it is necessary to evaluate the conversion efficiency of battery cells, so as to further improve the conversion efficiency of battery cells by optimizing the material and process level of battery cells. In related technologies, battery cells are often installed on test fixtures, and the IV curve corresponding to the battery cells is drawn, and the maximum power point is found on the IV curve, and then the conversion efficiency of the battery cells is calculated. The commonly used test method for the conversion efficiency of battery cells requires contact with the battery cells for measurement, which will cause damage to the battery cells; and most of the battery cells made by the new process do not have main grids, and IV tests cannot be performed, which makes it impossible to test the conversion efficiency of the battery cells, and the applicable scenarios are limited. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the related art. To this end, the present application proposes a method and device for detecting the conversion efficiency of a battery cell, which avoids direct contact between the probe and the battery cell, realizes contactless measurement of the conversion efficiency of the battery cell, and reduces damage to the battery cell; and measures the conversion efficiency of the battery cell based on photoluminescence, which is suitable for measuring battery cells without a main grid and has a wide range of applicable scenarios.

[0004] In a first aspect, the present application provides a method for detecting conversion efficiency of a battery cell, wherein the battery cell and a calibration object are placed within the field of view of an image sensor, the battery cell and the calibration object are placed on the same plane, at least two light source devices arranged on different sides of the image sensor are used to provide illumination to the battery cell and the calibration object, and the illumination projection area of ​​the at least two light source devices on the plane is larger than the coverage area of ​​the field of view on the plane; the method comprises:

[0005] In a case where the at least two light source devices operate based on a target light intensity, based on the image to be tested corresponding to the battery cell and the calibration object acquired by the image sensor, determining a first grayscale value of the calibration object in the image to be tested;

[0006] Based on the first grayscale value and the corresponding relationship between the image grayscale value and the light intensity, determining the actual light intensity corresponding to the image to be measured;

[0007] The conversion efficiency of the battery cell is calculated based on the actual light intensity, the first gray value, the first open circuit voltage of the calibration object under the target light intensity, and the second gray value of the battery cell in the image to be tested.

[0008] According to the battery cell conversion efficiency detection method provided in the embodiment of the present application, the light intensity is reflected by the image grayscale value, so that the actual light intensity corresponding to the image to be tested can be obtained based on the first grayscale value of the calibration object in the acquired image to be tested, so as to obtain the conversion efficiency of the battery cell based on the actual light intensity, the first grayscale value, the first open-circuit voltage of the calibration object and the second grayscale value of the battery cell in the image to be tested, thereby realizing the measurement of the conversion efficiency of the battery cell by photoluminescence, avoiding direct contact between the probe and the battery cell, realizing contactless measurement of the conversion efficiency of the battery cell, and reducing damage to the battery cell; and the measurement of the conversion efficiency of the battery cell based on photoluminescence is suitable for the measurement of battery cells without main grids, and has a wide range of applicable scenarios.

[0009] A method for detecting conversion efficiency of a battery cell according to an embodiment of the present application, wherein the conversion efficiency of the battery cell is calculated based on the actual light intensity, the first gray value, the first open circuit voltage of the calibration object under the target light intensity, and the second gray value of the battery cell in the image to be tested, comprises:

[0010] Based on the deviation between the actual light intensity and the target light intensity, a compensated open circuit voltage corresponding to the battery cell is calculated;

[0011] Calculating a second open circuit voltage corresponding to the battery cell based on the first gray value, the first open circuit voltage and the second gray value;

[0012] The conversion efficiency of the battery cell is obtained based on the compensated open-circuit voltage, the second open-circuit voltage, the actual light intensity, and physical parameters corresponding to the battery cell.

[0013] In a method for detecting conversion efficiency of a battery cell according to an embodiment of the present application, the physical parameters include a short-circuit current and a light-receiving area of ​​the battery cell; and obtaining the conversion efficiency of the battery cell based on the compensated open-circuit voltage, the second open-circuit voltage, the actual light intensity, and the physical parameters corresponding to the battery cell, comprises:

[0014] Obtaining an actual open circuit voltage corresponding to the battery cell based on the sum of the compensated open circuit voltage and the second open circuit voltage;

[0015] Based on the actual open circuit voltage, a fill factor corresponding to the battery cell is calculated;

[0016] The conversion efficiency of the battery cell is calculated based on the actual open circuit voltage, the short circuit current corresponding to the battery cell, the fill factor, the actual light intensity and the light receiving area.

[0017] A method for detecting conversion efficiency of a battery cell according to an embodiment of the present application, wherein the conversion efficiency of the battery cell is calculated based on the actual open circuit voltage, the short circuit current corresponding to the battery cell, the fill factor, the actual light intensity, and the light receiving area, comprises:

[0018] Obtaining a maximum output power corresponding to the battery cell based on the product of the actual open circuit voltage, the short circuit current and the fill factor;

[0019] Obtaining the input power corresponding to the battery cell based on the product of the actual light intensity and the light receiving area;

[0020] The conversion efficiency is obtained based on the ratio of the maximum output power to the input power.

[0021] A method for detecting conversion efficiency of a battery cell according to an embodiment of the present application, wherein the second open circuit voltage corresponding to the battery cell is calculated based on the first gray value, the first open circuit voltage and the second gray value, comprises:

[0022] Obtaining a thermal voltage corresponding to the battery cell at a target temperature;

[0023] Calculating a target constant based on the first gray value, the first open circuit voltage, and the thermal voltage;

[0024] The second open circuit voltage is calculated based on the second grayscale value, the target constant and the thermal voltage.

[0025] A method for detecting conversion efficiency of a battery cell according to an embodiment of the present application, obtaining a corresponding relationship between the grayscale value of the image and the light intensity, includes:

[0026] Acquire calibration images corresponding to the calibration object acquired by the image sensor when the at least two light source devices operate based on respective light intensities; the grayscale value of the calibration object in each of the calibration images is different;

[0027] Based on each of the light intensities and the calibration images corresponding to each of the light intensities, the corresponding relationship between the image grayscale value and the light intensities is constructed.

[0028] In a second aspect, the present application provides a battery cell conversion efficiency detection device, wherein the battery cell and the calibration object are placed within the field of view of an image sensor, the battery cell and the calibration object are placed on the same plane, at least two light source devices arranged on different sides of the image sensor are used to provide light to the battery cell and the calibration object, and the light projection area of ​​the at least two light source devices on the plane is larger than the coverage area of ​​the field of view on the plane; the device comprises:

[0029] A first processing module, configured to determine a first grayscale value of the calibration object in the image to be tested based on the image to be tested corresponding to the battery cell and the calibration object acquired by the image sensor when the at least two light source devices operate based on the target light intensity;

[0030] A second processing module, configured to determine an actual light intensity corresponding to the image to be measured based on the first grayscale value and a corresponding relationship between the image grayscale value and the light intensity;

[0031] The third processing module is used to calculate the conversion efficiency of the battery cell based on the actual light intensity, the first gray value, the first open circuit voltage of the calibration object under the target light intensity and the second gray value of the battery cell in the image to be tested.

[0032] According to the battery cell conversion efficiency detection device provided in the embodiment of the present application, the light intensity is reflected by the image grayscale value, so that the actual light intensity corresponding to the image to be tested can be obtained based on the first grayscale value of the calibration object in the acquired image to be tested, so as to obtain the conversion efficiency of the battery cell based on the actual light intensity, the first grayscale value, the first open-circuit voltage of the calibration object and the second grayscale value of the battery cell in the image to be tested, thereby realizing the measurement of the conversion efficiency of the battery cell by the photoluminescence method, avoiding the direct contact between the probe and the battery cell, realizing the contactless measurement of the conversion efficiency of the battery cell, and reducing the damage to the battery cell; and the measurement of the conversion efficiency of the battery cell based on the photoluminescence is suitable for the measurement of the battery cell without a main grid, and has a wide range of applicable scenarios.

[0033] In a third aspect, the present application provides a battery cell conversion efficiency detection system, comprising:

[0034] Image sensor;

[0035] At least two light source devices, the at least two light source devices are arranged on different sides of the image sensor, and the light projection area of ​​the at least two light source devices on the same plane is larger than the coverage area of ​​the field of view on the same plane;

[0036] The battery cell conversion efficiency detection device as described in the second aspect is used to detect the conversion efficiency of the battery cell based on the battery cell conversion efficiency detection method as described in the first aspect.

[0037] According to the battery cell conversion efficiency detection system provided in the embodiment of the present application, the light intensity is reflected by the image grayscale value, so that the actual light intensity corresponding to the image to be tested can be obtained based on the first grayscale value of the calibration object in the acquired image to be tested, so as to obtain the conversion efficiency of the battery cell based on the actual light intensity, the first grayscale value, the first open-circuit voltage of the calibration object and the second grayscale value of the battery cell in the image to be tested, thereby realizing the measurement of the conversion efficiency of the battery cell by the photoluminescence method, avoiding the direct contact between the probe and the battery cell, realizing the contactless measurement of the conversion efficiency of the battery cell, and reducing the damage to the battery cell; and the measurement of the conversion efficiency of the battery cell based on the photoluminescence is suitable for the measurement of the battery cell without a main grid, and has a wide range of applicable scenarios.

[0038] In a fourth aspect, the present application provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for detecting the conversion efficiency of a battery cell as described in the first aspect above is implemented.

[0039] In a fifth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the method for detecting conversion efficiency of a battery cell as described in the first aspect above is implemented.

[0040] In a sixth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the method for detecting conversion efficiency of a battery cell as described in the first aspect above.

[0041] The above one or more technical solutions in the embodiments of the present application have at least one of the following technical effects:

[0042] The light intensity is reflected by the image grayscale value, so that the actual light intensity corresponding to the image to be tested can be obtained based on the first grayscale value of the calibration object in the acquired image to be tested, and the conversion efficiency of the battery cell can be obtained based on the actual light intensity, the first grayscale value, the first open-circuit voltage of the calibration object and the second grayscale value of the battery cell in the image to be tested. The conversion efficiency of the battery cell can be measured by photoluminescence, which avoids direct contact between the probe and the battery cell, realizes contactless measurement of the conversion efficiency of the battery cell, and reduces damage to the battery cell. The measurement of the conversion efficiency of the battery cell based on photoluminescence is suitable for the measurement of battery cells without main grids, and has a wide range of applicable scenarios.

[0043] Furthermore, the conversion efficiency of the battery cell is calculated by a photoluminescence method, thereby achieving contactless measurement of the conversion efficiency of the battery cell and reducing damage to the battery cell caused by measurement.

[0044] Furthermore, by capturing images of the calibration object based on different light intensities before the test, recording the grayscale value of the calibration object in the calibration image, and then constructing a correspondence between the image grayscale value and the light intensity, each time the image of the battery cell is captured, the deviation or fluctuation of the light intensity can be inferred based on the grayscale value corresponding to the calibration object to obtain the actual light intensity, thereby improving the precision and accuracy of measuring the conversion efficiency of the battery cell.

[0045] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0047] Figure 1 It is a flow chart of a method for detecting conversion efficiency of a battery cell provided in an embodiment of the present application;

[0048] Figure 2 It is a structural schematic diagram of a battery cell conversion efficiency detection system provided in an embodiment of the present application;

[0049] Figure 3 is a schematic structural diagram of a battery cell conversion efficiency detection device provided in an embodiment of the present application;

[0050] Figure 4 It is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0052] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0053] In conjunction with the accompanying drawings, the battery cell conversion efficiency detection method, battery cell conversion efficiency detection device, electronic device and readable storage medium provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0054] The method for detecting the conversion efficiency of a battery cell may be applied to a terminal, and may be specifically executed by hardware or software in the terminal.

[0055] The terminal includes, but is not limited to, a portable communication device such as a mobile phone or tablet computer with a touch-sensitive surface (e.g., a touch screen display and / or a touch pad). It should also be understood that in some embodiments, the terminal may not be a portable communication device, but a desktop computer with a touch-sensitive surface (e.g., a touch screen display and / or a touch pad).

[0056] In the following various embodiments, a terminal including a display and a touch-sensitive surface is described. However, it should be understood that the terminal may include one or more other physical user interface devices such as a physical keyboard, a mouse and a joystick.

[0057] The conversion efficiency detection method of a battery cell provided in the embodiment of the present application may be executed by a conversion efficiency detection system or electronic device of the battery cell, or a functional module or functional entity in the conversion efficiency detection system or electronic device of the battery cell that can implement the conversion efficiency detection method of the battery cell. The electronic devices mentioned in the embodiment of the present application include but are not limited to mobile phones, tablet computers, computers, cameras, and wearable devices. The conversion efficiency detection method of a battery cell provided in the embodiment of the present application is described below using an electronic device as an example of the execution subject.

[0058] like Figure 1 As shown, the method for detecting conversion efficiency of a battery cell includes: step 110 , step 120 and step 130 .

[0059] It should be noted that the battery cell conversion efficiency detection method can be applied to a battery cell conversion efficiency detection system.

[0060] The conversion efficiency detection system of a battery cell may include: an image sensor and at least two light source devices.

[0061] The battery cell (the object to be tested) and the calibration object can be placed within the field of view of the image sensor, and the battery cell and the calibration object are located on the same plane.

[0062] The field of view of an image sensor is the maximum range of images that the image sensor can capture.

[0063] At least two light source devices are disposed on different sides of the image sensor. For example, at least two light source devices may be disposed on the left and right sides of the image sensor. The at least two light source sensors are used to provide light to the battery cells and the calibration object.

[0064] The illumination projection area of ​​at least two light source devices on the plane is larger than the coverage area of ​​the field of view on the plane, which can ensure that objects within the entire field of view can obtain sufficient illumination.

[0065] The position and parameters of the light source device can be set to ensure that the lighting is uniform across the entire field of view.

[0066] Step 110: when at least two light source devices are operating based on the target light intensity, based on the images to be tested corresponding to the battery cells and the calibration object acquired by the image sensor, determine a first grayscale value of the calibration object in the image to be tested;

[0067] In this step, the light source device may include a solar simulator, a monochromatic light source device or a double-sided array laser, etc. For example, a double-sided array laser may be used to provide illumination for the battery cell and the calibration object. The double-sided array laser may generate an adjustable illumination intensity, and the adjustable illumination intensity may range from 0.1 sun to 1 sun, where "sun" is the unit of sunlight intensity, and 1 sun is approximately equal to 1000 W / m 2 (On the Earth's surface, in a plane perpendicular to the sunlight).

[0068] The light source emitted by the light source device may be a surface spot laser light source in the 808 nm band, that is, the light emitted by the light source device has a uniform spot distribution at a specific wavelength (808 nm).

[0069] like Figure 2 As shown, the two light source devices can be placed at an angle to ensure uniform illumination on the detection surface of the image sensor.

[0070] The light source device can flash the light source, that is, the light source device can flash at a certain frequency. By flashing the light source, the temperature rise caused by the light source irradiating the battery cell for a long time can be reduced, ensuring that the temperature change of the battery cell is small during the detection of the battery cell.

[0071] When the double-sided array laser is turned on, its output power can be measured using an optical power meter, where the optical power meter is an instrument used to measure the power of an optical signal.

[0072] Based on the reading of the optical power meter, known optical power parameters (such as the efficiency and wavelength of the double-sided array laser, etc.), and the required 1Sun and 0.1Sun light intensities, a conversion can be performed to determine the actual power that the double-sided array laser should be set to.

[0073] According to the conversion result, the power controller of the double-sided array laser can be adjusted. For example, the power of the double-sided array laser can be set to 1sun. For example, the power of the double-sided array laser can be adjusted by adjusting parameters such as the current, voltage or duty cycle of the double-sided array laser.

[0074] The image sensor may include a PL camera (photoluminescence camera) and a lens filter, wherein the lens filter may be used to adjust the wavelength range of light entering the camera to filter out unwanted spectral components.

[0075] PL cameras can be set to use a 12-bit grayscale image (or higher). The bit depth of the grayscale image determines the color depth (i.e. brightness level) that can be represented by each pixel in the image.

[0076] For example, an 8-bit grayscale image can provide brightness levels from 0 to 255, and a 12-bit grayscale image can provide brightness levels from 0 to 4095.

[0077] In actual implementation, the power of each light source device may be adjusted to set the light intensity emitted by at least two light source devices to a target light intensity, wherein the target light intensity may be 1 sun.

[0078] The battery cell may be a cell with or without a busbar, for example, the battery cell may be an OBB (busbarless) cell, or may be a busbarless cell such as a BC (full back contact) cell.

[0079] The calibration object can be used for coefficient calibration. The calibration object can be a battery cell of the same type as the battery cell, such as Figure 2 As shown in the bid.

[0080] The image to be tested includes the imaging of the battery cell and the imaging of the calibration object.

[0081] In the acquired image to be tested, the calibration object can be found and its grayscale value can be determined, which is recorded as the first grayscale value.

[0082] For example, a plurality of grayscale values ​​corresponding to the calibration object in the image to be measured may be obtained, and an average value of the plurality of grayscale values ​​may be determined as the first grayscale value.

[0083] Step 120: determining the actual light intensity corresponding to the image to be measured based on the first grayscale value and the corresponding relationship between the image grayscale value and the light intensity;

[0084] In this step, the correspondence between the image grayscale value and the light intensity can be obtained through experiments or data fitting. For example, images of the calibration object can be taken under different lighting conditions and the corresponding light intensity can be recorded. These images are then grayscaled and the grayscale value at the same position of the calibration object in the image is extracted to establish the correspondence between the image grayscale value and the light intensity.

[0085] The first grayscale value may be substituted into the corresponding relationship between the image grayscale value and the light intensity to calculate the light intensity corresponding to the first grayscale value, thereby determining the actual light intensity corresponding to the image to be measured.

[0086] Step 130 : Calculate the conversion efficiency of the battery cell based on the actual light intensity, the first gray value, the first open circuit voltage of the calibration object under the target light intensity, and the second gray value of the battery cell in the image to be tested.

[0087] In this step, the first open circuit voltage of the calibration object under the target light intensity can be acquired in advance.

[0088] The open circuit voltage is the voltage when the two ends of the battery cell are open circuited under standard test conditions (STC).

[0089] Among them, the standard test conditions include: light intensity is 1000W / m 2 , the spectral distribution is AM1.5G (solar spectrum with air mass 1.5), and the battery temperature is 25°C.

[0090] In the acquired image to be tested, the battery cell can be found and its grayscale value can be determined, which is recorded as the second grayscale value.

[0091] For example, a plurality of grayscale values ​​corresponding to the battery cell in the image to be tested may be obtained, and an average value of the plurality of grayscale values ​​may be determined as the second grayscale value.

[0092] The conversion efficiency of a battery cell is used to characterize the ability of the battery cell to convert light energy into electrical energy.

[0093] The conversion efficiency of the battery cell can be calculated based on the actual light intensity received by the battery cell, the first gray value of the calibration object in the image to be tested, the first open circuit voltage of the calibration object under the target light intensity and the second gray value of the battery cell in the image to be tested.

[0094] According to the battery cell conversion efficiency detection method provided in the embodiment of the present application, the light intensity is reflected by the image grayscale value, so that the actual light intensity corresponding to the image to be tested can be obtained based on the first grayscale value of the calibration object in the acquired image to be tested, so as to obtain the conversion efficiency of the battery cell based on the actual light intensity, the first grayscale value, the first open-circuit voltage of the calibration object and the second grayscale value of the battery cell in the image to be tested, thereby realizing the measurement of the conversion efficiency of the battery cell by photoluminescence, avoiding direct contact between the probe and the battery cell, realizing contactless measurement of the conversion efficiency of the battery cell, and reducing damage to the battery cell; and the measurement of the conversion efficiency of the battery cell based on photoluminescence is suitable for the measurement of battery cells without main grids, and has a wide range of applicable scenarios.

[0095] In some embodiments, step 130 may include:

[0096] Based on the deviation between the actual light intensity and the target light intensity, the compensated open circuit voltage corresponding to the battery cell is calculated;

[0097] Based on the first gray value, the first open circuit voltage and the second gray value, a second open circuit voltage corresponding to the battery cell is calculated;

[0098] The conversion efficiency of the battery cell is obtained based on the compensated open-circuit voltage, the second open-circuit voltage, the actual light intensity and the physical parameters corresponding to the battery cell.

[0099] In this embodiment, the compensated open circuit voltage can be used to correct the voltage variation caused by the deviation of the light intensity.

[0100] During the stroboscopic lighting process of the light source device, the current value passing through the battery cell or calibration object each time may be unstable. When the temperature of the battery cell or calibration object changes, it will also cause the grayscale value of the battery cell or calibration object in the image to be tested to change, resulting in a deviation between the actual light intensity and the target light intensity.

[0101] The second open circuit voltage is the voltage when both ends of the battery cell are open circuited under standard test conditions.

[0102] The physical parameters corresponding to the battery cell may include the light receiving area, material type, and current parameters of the battery cell.

[0103] In some embodiments, obtaining the conversion efficiency of the battery cell based on the compensated open circuit voltage, the second open circuit voltage, the actual light intensity, and the physical parameters corresponding to the battery cell may include:

[0104] Based on the sum of the compensated open circuit voltage and the second open circuit voltage, an actual open circuit voltage corresponding to the battery cell is obtained;

[0105] Based on the actual open circuit voltage, the fill factor corresponding to the battery cell is calculated;

[0106] The conversion efficiency of the battery cell is calculated based on the actual open circuit voltage, the short circuit current corresponding to the battery cell, the fill factor, the actual light intensity and the light receiving area.

[0107] In this embodiment, based on the compensated open circuit voltage, the second open circuit voltage calculated based on the target light intensity can be corrected. For example, the sum of the compensated open circuit voltage and the second open circuit voltage can be determined as the actual open circuit voltage corresponding to the battery cell.

[0108] The fill factor corresponding to a battery cell is used to characterize the ratio of the area corresponding to the marked point (the maximum power that the battery can output) to the maximum area (theoretical power).

[0109] When the series resistance in the battery cell increases, the fill factor will decrease; when the parallel resistance in the battery cell decreases, the fill factor will decrease.

[0110] In actual implementation, without considering the series resistance in the battery cell, the fill factor can be calculated based on the following formula:

[0111]

[0112] Where FF0 is the fill factor calculated without considering the series resistance in the battery cell, v oc is the actual open circuit voltage corresponding to the battery cell, and C1 is an arbitrary constant.

[0113] Taking into account the series resistance in the battery cell, the fill factor can be calculated based on the following formula:

[0114]

[0115] Among them, FF s is the fill factor calculated with the series resistance in the battery cell considered, FF0 is the fill factor calculated without considering the series resistance in the battery cell, C2 and C3 are arbitrary constants, r s is the series resistance in the battery cell.

[0116] The physical parameters corresponding to the battery cell may include the short-circuit current and the light-receiving area of ​​the battery cell.

[0117] The short-circuit current is the maximum current that flows when the two ends of a battery cell are short-circuited under standard test conditions.

[0118] Based on the existing battery cell data of the manufacturer, short-circuit current data can be collected in batches, and then outliers in multiple short-circuit current data can be eliminated to obtain the average short-circuit current. Then, the short-circuit current density can be obtained based on the ratio of the average short-circuit current to the area of ​​the battery cell. The conventional short-circuit current density is 35 mA / cm 2 .

[0119] The light receiving area of ​​the battery cell is the area of ​​the surface of the battery cell facing the image sensor.

[0120] The conversion efficiency of the battery cell can be calculated based on the actual open circuit voltage, the short circuit current corresponding to the battery cell, the fill factor, the actual light intensity and the light receiving area of ​​the battery cell.

[0121] In some embodiments, the conversion efficiency of the battery cell is calculated based on the actual open circuit voltage, the short circuit current corresponding to the battery cell, the fill factor, the actual light intensity, and the light receiving area, which may include:

[0122] Based on the product of the actual open circuit voltage, short circuit current and fill factor, the maximum output power corresponding to the battery cell is obtained;

[0123] Based on the product of actual light intensity and light receiving area, the input power corresponding to the battery cell is obtained;

[0124] Based on the ratio of the maximum output power to the input power, the conversion efficiency is obtained.

[0125] In this embodiment, the maximum output power corresponding to the battery cell is the maximum power that the battery can provide under standard test conditions.

[0126] The input power corresponding to the battery cell is the power of the external energy source received by the battery. For example, when the battery cell is a solar panel, the input power is the power of sunlight shining on the panel.

[0127] The conversion efficiency can be obtained based on the ratio of maximum output power to input power. The conversion efficiency is used to characterize the ability of a battery cell to convert light energy into electrical energy.

[0128] In the actual implementation process, the conversion efficiency can be calculated based on the following formula:

[0129]

[0130] Among them, Eta is the conversion efficiency, Pm is the maximum output power, p in is the input power, v oc is the actual open circuit voltage corresponding to the battery cell, Jsc is the short circuit current corresponding to the battery cell, FF is the fill factor corresponding to the battery cell, Insol is the actual illumination intensity, and A is the light receiving area of ​​the battery cell.

[0131] In some embodiments, calculating the second open circuit voltage corresponding to the battery cell based on the first gray value, the first open circuit voltage, and the second gray value may include:

[0132] Obtain the thermal voltage corresponding to the battery cell at the target temperature;

[0133] Calculating a target constant based on the first gray value, the first open circuit voltage and the thermal voltage;

[0134] A second open circuit voltage is calculated based on the second grayscale value, the target constant and the thermal voltage.

[0135] In this embodiment, the thermal voltage is the potential difference across the battery cell at the target temperature.

[0136] The target temperature is room temperature, and the thermal voltage of a battery cell is generally about 26 mV at room temperature.

[0137] The first photoluminescence intensity corresponding to the calibration object may be characterized based on the first grayscale value of the calibration object in the image to be measured.

[0138] Based on the first open circuit voltage, the first photoluminescence intensity and the thermal voltage of the calibration object, the target constant can be calculated:

[0139]

[0140] Among them, C is the target constant, φ ref is the first photoluminescence intensity, v oc1 is the first open circuit voltage, v t is the thermal voltage.

[0141] The second photoluminescence intensity corresponding to the battery cell may be characterized based on the second gray value of the battery cell in the image to be tested.

[0142] Based on the second photoluminescence intensity, target constant and thermal voltage of the battery cell, the second open circuit voltage corresponding to the battery cell can be calculated:

[0143]

[0144] Among them, v oc2 is the second open circuit voltage, v t is the thermal voltage, C is the target constant, and φ(N) is the second photoluminescence intensity.

[0145] According to the battery cell conversion efficiency detection method provided in the embodiment of the present application, the conversion efficiency of the battery cell is calculated by a photoluminescence method, thereby realizing contactless measurement of the conversion efficiency of the battery cell and reducing damage to the battery cell caused by measurement.

[0146] In some embodiments, obtaining the corresponding relationship between the image grayscale value and the light intensity may include:

[0147] Acquire a calibration image corresponding to the calibration object captured by the image sensor when at least two light source devices operate based on respective light intensities;

[0148] Based on each light intensity and the calibration image corresponding to each light intensity, a corresponding relationship between the image grayscale value and the light intensity is constructed.

[0149] In this embodiment, the illumination intensity of at least two light source devices can be increased in sequence from 0.1 sun to 1 sun through preliminary calibration, for example, by increasing by 0.1 sun each time, and a calibration image corresponding to the calibration object captured by the image sensor when at least two light source devices operate at various illumination intensities is obtained.

[0150] When acquiring the calibration image, the grayscale value of the same part of the calibration object in the calibration image can be recorded.

[0151] The grayscale value of the calibration object in each calibration image is different.

[0152] By matching the grayscale value of the calibration object in the calibration image with the light intensity, a relationship curve between the grayscale value of the calibration object and the light intensity can be obtained.

[0153] For example, the recorded light intensity can be used as the horizontal coordinate and the corresponding image grayscale value as the vertical coordinate, and a relationship curve between the image grayscale value and the light intensity can be drawn using chart software (such as Excel or Python's matplotlib, etc.).

[0154] According to the battery cell conversion efficiency detection method provided in the embodiment of the present application, by capturing images of the calibration object based on different light intensities before the test, and recording the grayscale value of the calibration object in the calibration image, and then constructing a correspondence between the image grayscale value and the light intensity, each time the battery cell is captured, the deviation or fluctuation of the light intensity can be inferred based on the grayscale value corresponding to the calibration object to obtain the actual light intensity, thereby improving the precision and accuracy of measuring the conversion efficiency of the battery cell.

[0155] The conversion efficiency detection device of the battery cell provided in the present application is described below. The conversion efficiency detection device of the battery cell described below and the conversion efficiency detection method of the battery cell described above can be referred to each other.

[0156] The conversion efficiency detection method of a battery cell provided in the embodiment of the present application can be executed by a conversion efficiency detection device of a battery cell. In the embodiment of the present application, the conversion efficiency detection method of a battery cell performed by a conversion efficiency detection device of a battery cell is taken as an example to illustrate the conversion efficiency detection device of a battery cell provided in the embodiment of the present application.

[0157] The embodiment of the present application also provides a battery cell conversion efficiency detection device.

[0158] like Figure 3 As shown, in the battery cell conversion efficiency detection device, the battery cell and the calibration object are placed within the field of view of the image sensor, the battery cell and the calibration object are placed on the same plane, at least two light source devices arranged on different sides of the image sensor are used to provide light to the battery cell and the calibration object, and the light projection area of ​​the at least two light source devices on the plane is larger than the coverage area of ​​the field of view on the plane; the battery cell conversion efficiency detection device includes: a first processing module 310, a second processing module 320 and a third processing module 330.

[0159] The first processing module 310 is used to determine a first gray value of the calibration object in the image to be tested based on the image to be tested corresponding to the battery cell and the calibration object acquired by the image sensor when at least two light source devices are working based on the target light intensity;

[0160] A second processing module 320 is used to determine the actual light intensity corresponding to the image to be measured based on the first gray value and the corresponding relationship between the image gray value and the light intensity;

[0161] The third processing module 330 is used to calculate the conversion efficiency of the battery cell based on the actual light intensity, the first gray value, the first open circuit voltage of the calibration object under the target light intensity and the second gray value of the battery cell in the image to be tested.

[0162] According to the battery cell conversion efficiency detection device provided in the embodiment of the present application, the light intensity is reflected by the image grayscale value, so that the actual light intensity corresponding to the image to be tested can be obtained based on the first grayscale value of the calibration object in the acquired image to be tested, so as to obtain the conversion efficiency of the battery cell based on the actual light intensity, the first grayscale value, the first open-circuit voltage of the calibration object and the second grayscale value of the battery cell in the image to be tested, thereby realizing the measurement of the conversion efficiency of the battery cell by the photoluminescence method, avoiding the direct contact between the probe and the battery cell, realizing the contactless measurement of the conversion efficiency of the battery cell, and reducing the damage to the battery cell; and the measurement of the conversion efficiency of the battery cell based on the photoluminescence is suitable for the measurement of the battery cell without a main grid, and has a wide range of applicable scenarios.

[0163] In some embodiments, the third processing module 330 may also be used to:

[0164] Based on the deviation between the actual light intensity and the target light intensity, the compensated open circuit voltage corresponding to the battery cell is calculated;

[0165] Based on the first gray value, the first open circuit voltage and the second gray value, a second open circuit voltage corresponding to the battery cell is calculated;

[0166] The conversion efficiency of the battery cell is obtained based on the compensated open-circuit voltage, the second open-circuit voltage, the actual light intensity and the physical parameters corresponding to the battery cell.

[0167] In some embodiments, the physical parameters include short-circuit current and light-receiving area of ​​the battery cell; the third processing module 330 may also be used for:

[0168] Based on the sum of the compensated open circuit voltage and the second open circuit voltage, an actual open circuit voltage corresponding to the battery cell is obtained;

[0169] Based on the actual open circuit voltage, the fill factor corresponding to the battery cell is calculated;

[0170] The conversion efficiency of the battery cell is calculated based on the actual open circuit voltage, the short circuit current corresponding to the battery cell, the fill factor, the actual light intensity and the light receiving area.

[0171] In some embodiments, the third processing module 330 may also be used to:

[0172] Based on the product of the actual open circuit voltage, short circuit current and fill factor, the maximum output power corresponding to the battery cell is obtained;

[0173] Based on the product of actual light intensity and light receiving area, the input power corresponding to the battery cell is obtained;

[0174] Based on the ratio of the maximum output power to the input power, the conversion efficiency is obtained.

[0175] In some embodiments, the third processing module 330 may also be used to:

[0176] Obtain the thermal voltage corresponding to the battery cell at the target temperature;

[0177] Calculating a target constant based on the first gray value, the first open circuit voltage and the thermal voltage;

[0178] A second open circuit voltage is calculated based on the second grayscale value, the target constant and the thermal voltage.

[0179] In some embodiments, the battery cell conversion efficiency detection device may further include a fourth processing module, which is used to:

[0180] Acquire calibration images corresponding to the calibration object collected by the image sensor when at least two light source devices work based on respective light intensities; the grayscale value of the calibration object in each calibration image is different;

[0181] Based on each light intensity and the calibration image corresponding to each light intensity, a corresponding relationship between the image grayscale value and the light intensity is constructed.

[0182] The conversion efficiency detection device of the battery cell in the embodiment of the present application can be an electronic device, or a component in the electronic device, such as an integrated circuit or a chip. The electronic device can be a terminal, or it can be other devices other than the terminal. Exemplarily, the electronic device can be a mobile phone, a tablet computer, a laptop computer, a PDA, a vehicle-mounted electronic device, a mobile Internet device (Mobile Internet Device, MID), an augmented reality (augmented reality, AR) / virtual reality (virtual reality, VR) device, a robot, a wearable device, an ultra-mobile personal computer (ultra-mobile personal computer, UMPC), a netbook or a personal digital assistant (personal digital assistant, PDA), etc. It can also be a server, a network attached storage (Network Attached Storage, NAS), a personal computer (personal computer, PC), a television (television, TV), a teller machine or a self-service machine, etc., and the embodiment of the present application is not specifically limited.

[0183] The battery cell conversion efficiency detection device in the embodiment of the present application may be a device with an operating system. The operating system may be an Android operating system, an IOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0184] The battery conversion efficiency detection device provided in the embodiment of the present application can achieve Figure 1 to Figure 2 To avoid repetition, the various processes implemented by the method embodiment are not described here.

[0185] like Figure 2 As shown, in some embodiments, the embodiments of the present application also provide a battery cell conversion efficiency detection system, including: an image sensor, at least two light source devices and a battery cell conversion efficiency detection device.

[0186] In this embodiment, the image sensor may include a PL camera (photoluminescence camera) and a lens filter, wherein the lens filter may be used to adjust the wavelength range of light entering the camera to filter out unwanted spectral components.

[0187] PL cameras can be set to use a 12-bit grayscale image (or higher). The bit depth of the grayscale image determines the color depth (i.e. brightness level) that can be represented by each pixel in the image.

[0188] For example, an 8-bit grayscale image can provide brightness levels from 0 to 255, and a 12-bit grayscale image can provide brightness levels from 0 to 4095.

[0189] At least two light source devices are disposed on different sides of the image sensor. For example, at least two light source devices may be disposed on the left and right sides of the image sensor. The at least two light source sensors are used to provide light to the battery cells and the calibration object.

[0190] The battery cell (the object to be tested) and the calibration object can be placed within the field of view of the image sensor, and the battery cell and the calibration object are located on the same plane.

[0191] The illumination projection area of ​​at least two light source devices on the same plane is larger than the coverage area of ​​the field of view on the same plane.

[0192] The light source device may include a solar simulator, a monochromatic light source device or a double-sided array laser, etc.

[0193] The battery cell conversion efficiency detection device is the battery cell conversion efficiency detection device as described in any of the above embodiments.

[0194] The battery cell conversion efficiency detection device is used to detect the conversion efficiency of the battery cell based on the battery cell conversion efficiency detection method described in any of the above embodiments.

[0195] like Figure 2As shown, the battery cell (battery piece) and the calibration object (calibration piece) can be placed horizontally along the X-axis, the image sensor can be arranged above the plane where the battery cell and the calibration object are located, and the lens of the image sensor is facing the battery cell and the calibration object, and the two light source devices can be arranged on the left and right sides of the image sensor and tilted. For example, the angle between the main light beam of light source 1 in the two light source devices and the Y-axis can be angle 2, and the angle between the main light beam of light source 2 in the two light source devices and the Y-axis can be angle 1.

[0196] The light spots projected by the two light source devices onto the plane where the battery cells and the calibration object are located may be square light spots, and the two square light spots may be superimposed to make the plane where the battery cells and the calibration object are located uniform.

[0197] In some embodiments, the battery cell conversion efficiency detection system may further include: a temperature sensor, a host computer, and a display.

[0198] The temperature sensor is used to detect the temperature of the battery cell in real time.

[0199] The host computer can be connected to the image sensor, at least two light source devices and the temperature sensor respectively.

[0200] The host computer is used to send control instructions to each hardware device and receive data from each device.

[0201] The display can be connected to the host computer, and the display can be used to display the data and image information processed by the host computer. For example, the display can display the image to be tested acquired by the image sensor.

[0202] According to the battery cell conversion efficiency detection system provided in the embodiment of the present application, the light intensity is reflected by the image grayscale value, so that the actual light intensity corresponding to the image to be tested can be obtained based on the first grayscale value of the calibration object in the acquired image to be tested, so as to obtain the conversion efficiency of the battery cell based on the actual light intensity, the first grayscale value, the first open-circuit voltage of the calibration object and the second grayscale value of the battery cell in the image to be tested, thereby realizing the measurement of the conversion efficiency of the battery cell by the photoluminescence method, avoiding the direct contact between the probe and the battery cell, realizing the contactless measurement of the conversion efficiency of the battery cell, and reducing the damage to the battery cell; and the measurement of the conversion efficiency of the battery cell based on the photoluminescence is suitable for the measurement of the battery cell without a main grid, and has a wide range of applicable scenarios.

[0203] In some embodiments, Figure 4As shown, an embodiment of the present application also provides an electronic device 400, including a processor 401, a memory 402, and a computer program stored in the memory 402 and executable on the processor 401. When the program is executed by the processor 401, each process of the above-mentioned battery cell conversion efficiency detection method embodiment is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0204] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0205] On the other hand, the present application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute the various processes of the above-mentioned battery cell conversion efficiency detection method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0206] On the other hand, the present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to execute the various processes of the above-mentioned battery cell conversion efficiency detection method embodiment and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0207] On the other hand, an embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned battery cell conversion efficiency detection method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0208] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0209] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0210] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware. Based on this understanding, the above technical solution can be essentially or in other words, the part that contributes to the relevant technology can be embodied in the form of a software product, which can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiment.

[0211] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for detecting conversion efficiency of a battery cell, characterized in that: The battery cell and the calibration object are placed within the field of view of the image sensor, the battery cell and the calibration object are placed on the same plane, at least two light source devices arranged on different sides of the image sensor are used to provide light to the battery cell and the calibration object, and the light projection area of ​​the at least two light source devices on the plane is larger than the coverage area of ​​the field of view on the plane; the method comprises: In a case where the at least two light source devices operate based on a target light intensity, based on the image to be tested corresponding to the battery cell and the calibration object acquired by the image sensor, determining a first grayscale value of the calibration object in the image to be tested; Based on the first grayscale value and the corresponding relationship between the image grayscale value and the light intensity, determining the actual light intensity corresponding to the image to be measured; The conversion efficiency of the battery cell is calculated based on the actual light intensity, the first gray value, the first open circuit voltage of the calibration object under the target light intensity, and the second gray value of the battery cell in the image to be tested.

2. The method for detecting conversion efficiency of a battery cell according to claim 1, characterized in that: The calculating the conversion efficiency of the battery cell based on the actual light intensity, the first gray value, the first open circuit voltage of the calibration object under the target light intensity and the second gray value of the battery cell in the image to be tested includes: Based on the deviation between the actual light intensity and the target light intensity, a compensated open circuit voltage corresponding to the battery cell is calculated; Calculating a second open circuit voltage corresponding to the battery cell based on the first gray value, the first open circuit voltage and the second gray value; The conversion efficiency of the battery cell is obtained based on the compensated open-circuit voltage, the second open-circuit voltage, the actual light intensity, and physical parameters corresponding to the battery cell.

3. The method for detecting conversion efficiency of a battery cell according to claim 2, characterized in that: The physical parameters include a short-circuit current and a light-receiving area of ​​the battery cell; and obtaining the conversion efficiency of the battery cell based on the compensated open-circuit voltage, the second open-circuit voltage, the actual light intensity, and the physical parameters corresponding to the battery cell, includes: Obtaining an actual open circuit voltage corresponding to the battery cell based on the sum of the compensated open circuit voltage and the second open circuit voltage; Based on the actual open circuit voltage, a fill factor corresponding to the battery cell is calculated; The conversion efficiency of the battery cell is calculated based on the actual open circuit voltage, the short circuit current corresponding to the battery cell, the fill factor, the actual light intensity and the light receiving area.

4. The method for detecting conversion efficiency of a battery cell according to claim 3, characterized in that: The calculating the conversion efficiency of the battery cell based on the actual open circuit voltage, the short circuit current corresponding to the battery cell, the fill factor, the actual light intensity and the light receiving area includes: Obtaining a maximum output power corresponding to the battery cell based on the product of the actual open circuit voltage, the short circuit current and the fill factor; Obtaining the input power corresponding to the battery cell based on the product of the actual light intensity and the light receiving area; The conversion efficiency is obtained based on the ratio of the maximum output power to the input power.

5. The method for detecting conversion efficiency of a battery cell according to claim 2, characterized in that: The calculating the second open circuit voltage corresponding to the battery cell based on the first gray value, the first open circuit voltage and the second gray value includes: Obtaining a thermal voltage corresponding to the battery cell at a target temperature; Calculating a target constant based on the first gray value, the first open circuit voltage, and the thermal voltage; The second open circuit voltage is calculated based on the second grayscale value, the target constant and the thermal voltage.

6. The method for detecting conversion efficiency of a battery cell according to any one of claims 1 to 5, characterized in that: Obtaining the corresponding relationship between the grayscale value of the image and the light intensity includes: Acquire calibration images corresponding to the calibration object collected by the image sensor when the at least two light source devices operate based on respective light intensities; the grayscale value of the calibration object in each of the calibration images is different; Based on each of the light intensities and the calibration images corresponding to each of the light intensities, the corresponding relationship between the image grayscale value and the light intensities is constructed.

7. A battery cell conversion efficiency detection device, characterized in that: The battery cell and the calibration object are placed within the field of view of the image sensor, the battery cell and the calibration object are placed on the same plane, at least two light source devices arranged on different sides of the image sensor are used to provide light to the battery cell and the calibration object, and the light projection area of ​​the at least two light source devices on the plane is larger than the coverage area of ​​the field of view on the plane; the device comprises: A first processing module, configured to determine a first grayscale value of the calibration object in the image to be tested based on the image to be tested corresponding to the battery cell and the calibration object acquired by the image sensor when the at least two light source devices operate based on the target light intensity; A second processing module, configured to determine an actual light intensity corresponding to the image to be measured based on the first grayscale value and a corresponding relationship between the image grayscale value and the light intensity; The third processing module is used to calculate the conversion efficiency of the battery cell based on the actual light intensity, the first gray value, the first open circuit voltage of the calibration object under the target light intensity and the second gray value of the battery cell in the image to be tested.

8. A battery cell conversion efficiency detection system, characterized in that: include: Image sensor; At least two light source devices, the at least two light source devices are arranged on different sides of the image sensor, and the light projection area of ​​the at least two light source devices on the same plane is larger than the coverage area of ​​the field of view on the same plane; The battery cell conversion efficiency detection device as claimed in claim 7, wherein the battery cell conversion efficiency detection device is used to detect the conversion efficiency of the battery cell based on the battery cell conversion efficiency detection method as claimed in any one of claims 1-6.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the method for detecting conversion efficiency of a battery cell as described in any one of claims 1 to 6 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for detecting conversion efficiency of a battery cell as claimed in any one of claims 1 to 6 is implemented.

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