Moire instrument for measuring warping degree of lithium battery

Abstract

The utility model provides a moire instrument for measuring the warping degree of a lithium battery, and the moire instrument comprises a moire sheet which is horizontally disposed on the surface of the lithium battery; the moire sheet comprises a moire sheet film and optical glass, and the edge of the moire sheet film is adhered to the optical glass; the camera is arranged above the moire sheet and is used for shooting moire patterns formed on the moire sheet; the light source is arranged above the moire sheet and is used for emitting light to irradiate the moire sheet; the centers of the camera, the light source and the moire sheet are located on the same plane.

Description

Technical Field

[0001] This utility model belongs to the field of lithium battery performance testing technology, and relates to a moiré meter for measuring the warpage of lithium batteries. Background Technology

[0002] With the widespread application of lithium batteries in various fields, the quality and performance testing of lithium batteries has become crucial. Among these, the warpage of a lithium battery is a significant factor affecting its performance and safety. Traditional measuring tools suffer from problems such as large errors and complex operation. Currently, there is a lack of a high-precision, easy-to-use measuring tool specifically designed for the characteristics of lithium batteries when measuring lithium battery warpage. Summary of the Invention

[0003] This invention provides a moiré pattern sheet and moiré instrument for measuring the warpage of lithium batteries, which can effectively solve the above-mentioned problems.

[0004] This utility model is implemented as follows:

[0005] This utility model provides a moiré pattern meter for measuring the warpage of lithium batteries, the moiré pattern meter comprising:

[0006] A cloud-patterned sheet, the cloud-patterned sheet being placed horizontally on the surface of a lithium battery;

[0007] The mottled sheet comprises: a mottled sheet film and optical glass, wherein the edge of the mottled sheet film is adhered to the optical glass;

[0008] A camera, positioned above the cloud pattern sheet, is used to photograph the cloud pattern formed on the cloud pattern sheet;

[0009] A light source is positioned above the cloud-patterned sheet to emit light and illuminate the cloud-patterned sheet;

[0010] The centers of the camera, the light source, and the mottled pattern are located on the same plane.

[0011] The beneficial effects of this utility model are:

[0012] This invention provides a moiré pattern meter for measuring the warpage of lithium batteries. Based on the shadow moiré pattern method, it measures the warpage of the lithium battery surface. The moiré pattern sheet is used to convert the tiny displacement of the warpage deformation into moiré fringes (moiré patterns) under a light source. The spacing of the moiré patterns is much larger than the grating period, thereby amplifying the tiny displacement. The moiré pattern is captured by a camera and analyzed to quantify the warpage.

[0013] Furthermore, the moiré pattern sheet used in the moiré pattern instrument is made by attaching a moiré pattern sheet film with an etched grating onto optical glass, thereby meeting the measurement accuracy requirements of the surface warp of lithium batteries, and the preparation method is simple and low in cost.

[0014] Furthermore, the cloud-patterned film of the cloud pattern adopts a concentric circle grating structure, which has a high degree of regularity and repeatability, and is sensitive to minute deformations. It can clearly and sensitively reflect the degree of warpage, and facilitate the quantification of warpage by observing changes in the cloud pattern. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the cloud pattern instrument provided in this embodiment of the utility model.

[0017] Figure 2 This is a first structural schematic diagram of the cloud-patterned sheet provided in an embodiment of the present utility model.

[0018] Figure 4 This is a schematic diagram of the second structure of the cloud-patterned sheet provided in an embodiment of the present utility model.

[0019] Figure 3 This is a schematic diagram of a cloud-patterned sheet placed on the surface of a lithium battery.

[0020] Figure 5 This is a schematic diagram showing the warping of the lithium battery surface.

[0021] Figure 6 This is a diagram showing the result of measuring the height of a spherical crown using the cloud pattern instrument provided in this embodiment of the utility model.

[0022] Figure 7 This is a photograph of the surface warpage of a 280Ah lithium battery measured by the moiré pattern measuring instrument provided in this embodiment of the present invention.

[0023] Figure 8 This is a graph showing the result of measuring the surface warpage of a 280Ah lithium battery using the moiré pattern measuring instrument provided in this embodiment of the present invention. Detailed implementation method:

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely represents selected embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0025] This utility model provides a moiré meter for measuring the warpage of lithium batteries. Please refer to [reference needed]. Figure 1 As shown, the cloud pattern instrument includes:

[0026] Cloud-patterned sheet 1, which is used to be placed horizontally on the surface of lithium battery 2.

[0027] Please refer to Figure 2 As shown, the mottled sheet 1 includes a mottled sheet film 11 and an optical glass 12, with the edge of the mottled sheet film 11 adhered to the optical glass 12.

[0028] Currently available moiré patterns are fabricated by etching grating structures directly onto optical glass. This process becomes significantly more complex as the size of the moiré pattern increases, and it's difficult to guarantee the uniformity and accuracy of the grating on large-sized materials. To meet precision requirements, only small-sized moiré patterns can be manufactured to ensure quality, making them suitable only for electronic components. However, lithium battery surface warping occurs at the micrometer level. If these moiré patterns were enlarged to a size suitable for lithium batteries, the required accuracy for measuring lithium battery surface warping would be insufficient.

[0029] In this embodiment of the invention, a mottled film 11 with an etched grating structure is adhered to an optical glass 12 to form a mottled sheet 1. The etching process of the mottled film 11 is simpler than that of the optical glass 12, overcoming the challenges posed by size. Furthermore, the dimensional accuracy and spacing accuracy of the grating formed on it can meet the high-precision measurement requirements of the surface warpage of lithium batteries.

[0030] Furthermore, the mottled film 11 has poor toughness and will bend if placed directly on the surface of the lithium battery, failing to maintain good flatness. Therefore, it is bonded to the optical glass 12.

[0031] In particular, the cloud-patterned sheet 1 can be used to measure the surface warpage of large 280Ah square batteries.

[0032] In some embodiments, the material of the mottled film 11 is PET or PC.

[0033] When the mottled sheet 1 is placed on the surface of the lithium battery, the surface in direct contact is the surface corresponding to the mottled sheet film 11. Both PET and PC have good chemical stability, which can reduce the possible corrosion of the mottled sheet 1 by the electrolyte.

[0034] Moreover, PET and PC have low coefficients of thermal expansion, which can reduce the thermal expansion and contraction of materials caused by changes in ambient temperature, and prevent the cloud pattern and spacing accuracy from being affected.

[0035] In addition, PET and PC have good light transmittance.

[0036] In some embodiments, the coefficient of thermal expansion α of the optical glass 12 is... 100 / 300℃ 1×10 -5 / K-1×10 -6 / K.

[0037] The coefficient of thermal expansion of optical glass 12 is lower than that of moiré film 11. Therefore, it is advisable to select glass with a coefficient of thermal expansion that matches that of moiré film 11 (10). -5 Optical glass 12 (grade).

[0038] In some embodiments, the cloud-patterned sheet 1 has a length of 15-35cm and a width of 15-35cm.

[0039] The surface dimensions of a 280Ah lithium battery are typically 15-25cm.

[0040] Correspondingly, the optical glass 12 is 15-35cm long and 15-35cm wide.

[0041] The dimensions of the mottled sheet 1 on the plane are adapted to the surface of the lithium battery 2 being measured. That is, the dimensions of both the optical glass substrate 12 and the mottled sheet film 11 on the plane are set according to the dimensions of the surface of the lithium battery 2 being measured.

[0042] Please refer to Figure 3 As shown, the left figure is a schematic diagram of lithium battery 2, where the gray area represents the surface of lithium battery 2 for which warpage measurement is performed. In the right figure, the blue part on the gray area represents the mottled sheet 1 placed on the surface of lithium battery 2.

[0043] It should be noted that the size of the mottled sheet 1 may be greater than, equal to or smaller than the size of the measured surface of the lithium battery 2.

[0044] For example, in some embodiments, the size of the mottled sheet 1 is 32cm × 32cm. The size of the surface of the lithium battery 2 is 20.7cm × 17.3cm.

[0045] In some embodiments, the thickness of the optical glass 12 is 1.5-2.5 mm.

[0046] The optical glass 12 needs to have a certain thickness to provide strength for the moiré film 11 to which it is attached, so that the moiré film 11 remains flat on the surface of the lithium battery, thereby ensuring the optical performance of the moiré film 11, so that the resulting moiré pattern can clearly and sensitively reflect the degree of warpage.

[0047] However, if the optical glass 12 is too thick, it will increase costs, including material costs and processing costs for making the moiré pattern 1. Furthermore, it will inevitably increase the propagation distance of light within the glass 12, leading to more light absorption and scattering, thus reducing light transmittance and the clarity of the moiré pattern captured by the camera. Additionally, the thickness of the glass will increase its coefficient of thermal expansion, thereby affecting the accuracy and stability of the optical system.

[0048] The selection of optical glass 12 and mottled film 11 is mainly based on the following criteria:

[0049] 1. High transparency:

[0050] It allows light to pass through efficiently, minimizing light absorption and scattering to ensure clear and realistic images. This is crucial for optical systems, enabling observers to obtain accurate and clear images.

[0051] 2. High chemical stability:

[0052] It does not readily react with other chemicals and has strong corrosion resistance. During long-term use, it maintains the stability of its optical properties and physical structure, and will not deteriorate or be damaged by contact with air, moisture, or chemical reagents.

[0053] In particular, compatibility with the lithium battery testing environment must be considered. Lithium batteries may contain chemicals such as electrolytes.

[0054] 3. Good uniformity of physical properties:

[0055] Its internal structure and physical properties are very uniform in all directions, which means that when light passes through the optical glass, its optical parameters such as refractive index and scattering rate are consistent regardless of which direction the light enters, thus ensuring the accuracy of the optical system and the quality of the images acquired by the camera.

[0056] 4. Specific and accurate optical constants:

[0057] It has well-defined and stable optical constants such as refractive index and dispersion coefficient, which are the basis for optical design and manufacturing.

[0058] 5. Good thermal stability:

[0059] It can maintain the stability of its optical performance and physical structure within a certain temperature range. When the temperature changes, the refractive index, size and other parameters of the optical glass 12 change very little.

[0060] In particular, the material should have a good coefficient of thermal expansion. When the lithium battery is fully charged and discharged, the surface temperature is high. It is necessary to avoid changes in the optical properties or physical structure of the mottled sheet 1 due to the surface temperature of the lithium battery, so as to ensure the accuracy of the measurement results.

[0061] Furthermore, the mottled film 11 and the optical glass 12 should be selected from materials with matching coefficients of thermal expansion to reduce stress caused by thermal expansion mismatch.

[0062] 6. High hardness:

[0063] It is wear-resistant and scratch-resistant. During daily use and processing, it is not easily scratched or worn, thus maintaining the optical properties of its surface and giving the resulting optical system a longer service life.

[0064] 7. Good processability

[0065] Various processing techniques, such as cutting, grinding, and polishing, can be used to create optical glass of various shapes and sizes to meet the testing requirements of lithium batteries of different sizes. Furthermore, during processing, the optical glass 12 maintains high precision, surface quality, and optical properties.

[0066] Specifically, the method for preparing the mottled pattern 1 includes:

[0067] S1. First, the optical glass 12 is cut and polished according to the (length and width) dimensions of the mottled film 11. Then, it is cleaned in an ultrasonic cleaner with organic solvents (such as acetone, ethanol, etc.) to remove surface oil and impurities. Then, it is rinsed with deionized water and dried in a clean environment.

[0068] In some implementation methods, please refer to Figure 4 As shown, the mottled sheet 1 further includes an adhesion layer 13, which is disposed on the surface of the optical glass 12 on the side close to the mottled sheet film 11.

[0069] Accordingly, the preparation method of the mottled pattern 1 includes:

[0070] S11, the dried optical glass 12 substrate is surface treated by forming a uniform, nano-thickness-scale adhesion layer 13 on the substrate surface through chemical coating or physical vapor deposition, so as to enhance the adhesion between the strong adhesive layer and the substrate in step S2.

[0071] In some embodiments, the thickness of the augmentation layer 13 is 20-80 nm.

[0072] Within this thickness range, the adhesion layer 13 can provide a certain degree of adhesion enhancement, while also reducing the impact of the thickness of the adhesion layer 13 on the optical system of the moirée instrument. For example, it can prevent the gap between the moirée film 11 and the optical glass 12 from being too large (due to the influence of the superimposed strong adhesive layer), which would affect the flatness of the moirée film 11 and also control costs.

[0073] In some embodiments, the material of the adhesion layer 13 is silicon dioxide.

[0074] Using silica as the adhesion-enhancing layer 13, combined with appropriate preparation processes, can significantly improve the adhesion between the substrate and the subsequent strong adhesive layer, while maintaining good optical and chemical properties.

[0075] S2, apply or attach strong adhesive to the edges of the optical glass 12 with the strong adhesive layer attached, and then attach the mottled film 11 to the substrate of the optical glass 12 so that the two are horizontally attached.

[0076] Right now Figure 4 The mottled film 11 and the adhesive layer 13 shown are connected by strong adhesive around their edges.

[0077] In some implementations, heating further crosslinks and cures the super glue.

[0078] Specifically, the heating temperature is 100-150℃, and the heating time is 10-30 minutes.

[0079] In some implementation methods, please refer to Figure 4 As shown, the cloud-patterned sheet 1 further includes a protective layer 14, which is disposed on the surface of the cloud-patterned sheet 1 and is transparent.

[0080] In some embodiments, the protective layer 14 is disposed on the surface of the mottled film 11 on the side away from the optical glass 12.

[0081] Accordingly, the preparation method of the mottled pattern 1 includes:

[0082] S21, a protective layer 14 is formed on the surface of the mottled sheet 1 by means of bonding or coating. The material of the protective layer 14 can be a transparent polymer film. The protective layer 14 covers the surface of the mottled sheet 1 to prevent the mottled sheet 1 from being scratched or contaminated during use.

[0083] In some embodiments, the grating spacing on the mottled film 11 is 120-180 μm.

[0084] First, for the same degree of warpage, as the grating spacing increases, the number of bright and dark stripes in the cloud pattern formed during the test decreases accordingly, or in other words, the spacing between the stripes increases.

[0085] If the grating spacing is too large, the light and dark stripes in the cloud pattern formed during the test will lack regularity, making it difficult to quantify the warping by observing the changes in the cloud pattern.

[0086] If the grating spacing is too small, it will increase the manufacturing cost of the mottled film 11 on the one hand, and on the other hand, it will cause the spacing of the stripes in the formed mottled pattern to be too small, making it difficult to distinguish the stripes.

[0087] In some embodiments, the gratings on the mottled sheet 1 are arranged in concentric circles. That is, the gratings on the mottled sheet film 11 are arranged in concentric circles.

[0088] Specifically, the center of the concentric circles is set at the center of the mottled film 11.

[0089] The cloud-patterned thin film 11 adopts a concentric circle grating structure, which has a high degree of regularity and repeatability, and is sensitive to minute deformations. It can clearly and sensitively reflect the degree of warpage, and make it convenient to quantify the degree of warpage by observing changes in the cloud pattern.

[0090] Camera 3 is positioned above the cloud pattern sheet 1 and is used to photograph the cloud pattern formed on the cloud pattern sheet 1.

[0091] Light source 4 is disposed above the cloud-patterned sheet 1 and is used to emit light to illuminate the cloud-patterned sheet 1.

[0092] The centers of the camera 3, the light source 4, and the cloud-patterned sheet 1 are located on the same plane.

[0093] The moiré meter is used to measure the surface warpage of lithium batteries.

[0094] Please refer to Figure 5As shown, surface warping of lithium battery products during the manufacturing process is a common quality issue. Surface warping can disrupt the structural stability of the battery's internal structure, leading to poor charge conduction, reduced charge and discharge efficiency and cycle life, and may also damage the separator between the electrodes and the electrolyte, increasing the risk of short circuits and potentially causing fires or explosions.

[0095] The principle behind the moiré meter for measuring the surface warpage of lithium battery 2 is the shadow moiré method. This method utilizes the projection and occlusion effects of a grating within a geometric optical framework to convert the height variation of an object's surface into a visible moiré pattern. When a reference grating and a shadow grating after the object's surface deformation are superimposed, if their periods are similar but there is a slight displacement, moiré fringes (moiré patterns) will be formed. The spacing of the moiré patterns is much larger than the grating period, thus amplifying the slight displacement and making it easier to observe.

[0096] Camera 3 is able to capture the stripes in the shading pattern because it can collect and record the light reflected from the object's surface. These light rays contain information about the grating shadows, and through Camera 3's imaging system, the stripe pattern on the object's surface can be clearly presented.

[0097] In some implementation methods, please refer to Figure 1 As shown, the angle formed by the line connecting the centers of the camera 3 and the cloud pattern 1 and the normal at the center of the cloud pattern 1 is β, where β = 0°.

[0098] When camera 3 is positioned vertically (i.e., aligned with the normal direction of the object's surface), the light propagation path is symmetrical, enabling the capture of light reflected or diffracted from the entire object's surface, thus obtaining a complete cloud pattern. Observing the cloud pattern from a vertical position minimizes angular distortion, ensuring the integrity and accuracy of the pattern. Simultaneously, the light intensity distribution on the observed object's surface is relatively uniform, allowing for clear capture of the cloud pattern's contrast.

[0099] In some embodiments, the light source 4 is a spotlight with a brightness of 500-1100 LM.

[0100] Since the brightness of the cloud pattern decreases as the level increases, light source 4 needs to provide sufficient light intensity to ensure the formation of the cloud pattern and the clarity of the cloud pattern obtained in further photography.

[0101] In some implementation methods, please refer to Figure 1 As shown, the angle formed by the line connecting the centers of the light source 4 and the cloud pattern 1 and the normal at the center of the cloud pattern 1 is α, where α = 45°.

[0102] When incident light shines at a 45° angle, the periodic structure of the grating projects a shadow on the object's surface. If there is a height difference Δh on the object's surface, the shadow will produce a horizontal displacement Δx. Since the incident angle θ = 45° and tanθ = 1, Δx = Δh. That is, the height difference is directly converted into a horizontal displacement.

[0103] In some implementations, the camera 3 and the light source 4 are at the same height from the same horizontal plane (the horizontal plane on which the lithium battery 2 is placed), ensuring that the light evenly covers the surface of the lithium battery 2.

[0104] In some embodiments, the moiré pattern instrument further includes:

[0105] The first bracket 5 is used to mount the camera 3;

[0106] The second bracket 6 is used to install the light source 4.

[0107] The first bracket 5 and the second bracket 6 are placed on a horizontal surface. The function of the first bracket 5 and the second bracket 6 is to position the camera 3 and the light source 4 above the mottled plate 1, respectively.

[0108] Since the thickness of the lithium battery 2 being measured may vary, it is generally necessary to adjust the distances between the camera 3 and the light source 4 and the moiré pattern 1, or the distance between the two, separately during measurement. Therefore, the first support 5 and the second support 6 are designed to be movable and height-adjustable.

[0109] Meanwhile, in order to adjust the incident angle of the light, the second bracket 6 is provided with an angle adjustment mechanism 61 for adjusting the illumination angle of the light source.

[0110] In some implementations...

[0111] In some embodiments, the moiré pattern analyzer further includes a processor for outputting measurement results.

[0112] The processor is used to receive the cloud pattern data collected by the camera 3. The processor can process and analyze the data according to the preset algorithm to quickly obtain the measurement result of the surface warp of the lithium battery 2.

[0113] Example 1

[0114] Preparation of mottled flake 1:

[0115] The cloud-patterned sheet 1 was prepared according to the above-described preparation method.

[0116] The optical glass substrate measures 20cm x 20cm and is 2mm thick.

[0117] Optical glass 12 was purchased from Qingyong Glass Cutting Shop in Jimei District, Xiamen City.

[0118] Use vernier calipers to measure the thickness in each direction to reduce the deformation of the cloud pattern caused by uneven base thickness and uneven spacing of cloud stripes.

[0119] The mottled sheet film 11 was purchased from Jiudi Microelectronics Technology (Hubei) Co., Ltd. Its thickness is 0.5 mm. The gratings on the mottled sheet film 11 are arranged in concentric circles. The grating spacing ε is 150 μm. The widths of the transparent and opaque areas are equal (duty cycle 50%).

[0120] The cloud-patterned sheet 1 includes an additional layer 13.

[0121] Specifically, a uniform silicon dioxide coating layer 13 with a thickness of 50 nm is formed on the surface of the optical glass 12 substrate in the mottled sheet 1 near the mottled sheet film 11 by physical vapor deposition.

[0122] Hot-melt adhesive tape is applied to the periphery of the surface of the optical glass 12 with the adhesion layer 13. Then, the mottled film 11 is adhered to the optical glass 12 substrate with the adhesive tape, so that the two are horizontally bonded. The tape is heated at 120°C for 20 minutes to further cross-link and cure.

[0123] Specifically, the width of the adhesive layer after heating is 1cm and the thickness is 0.05mm.

[0124] The cloud-patterned sheet 1 includes a protective layer 14.

[0125] Specifically, a uniform, transparent polymer protective film with a thickness of 0.1 mm is formed on the surface of the mottled film 11 away from the substrate of the optical glass 12 by bonding.

[0126] The setup of the cloud pattern instrument:

[0127] A sphere with a radius R of 5 cm is placed on a horizontal surface, and then a mottled sheet 1 is placed horizontally on the sphere. The mottled sheet film 11 of the mottled sheet 1 faces downward and is in direct contact with the sphere.

[0128] Specifically, by setting support structures on both sides of the sphere at the same height as the top of the sphere, the cloud-patterned piece 1 is placed horizontally on the sphere.

[0129] Light source 4 is used to illuminate cloud pattern sheet 1, so that a stable cloud pattern is formed on cloud pattern sheet 1. The angle between the line connecting the center of light source 4 and cloud pattern sheet 1 and the normal at the center of cloud pattern sheet 1 is 45°.

[0130] Light source 3 is a spotlight with a brightness of 1000LM.

[0131] The cloud pattern is photographed using camera 3 to obtain an image. The line connecting the centers of camera 3 and cloud pattern piece 1 coincides with the normal at the center of cloud pattern piece 1.

[0132] Please refer to Figure 6 As shown in the image, there is a dark stripe at the bottom radius x of 15cm corresponding to the top of the sphere. Counting the dark stripes on the crown part of the sphere, the number of dark stripes is 15 (excluding the dark spot in the center).

[0133] The reason for the dark spot at the center is likely because the curvature of the sphere is much greater than that of the plane, causing the grating to be misaligned by half a period. Therefore, the dark fringes are used for calculations without affecting the accuracy of the optical system.

[0134] The height of the crown:

[0135] Calculated based on the radius R of the sphere:

[0136] The moiré pattern instrument measured:

[0137] The height value of the spherical crown obtained by the moiré meter is the same as the actual value, indicating that the moiré meter has almost no error in the micron-level measurement and its accuracy can meet the requirements for measuring the surface warp of lithium battery 2.

[0138] Example 2

[0139] Please refer to Figure 1 and 7 As shown, the sphere in Example 1 was replaced with a 280Ah lithium battery 2, and the surface warpage of the lithium battery 2 was measured using the moiré meter described in Example 1.

[0140] Specifically, the brand of lithium battery 2 is CATL (Contemporary Amperex Technology Co., Limited).

[0141] Please refer to the measurement results. Figure 8 As shown.

[0142] It should be noted that in this embodiment of the present invention, the warpage of the lithium battery 2 surface fails to cause the grating to produce a misaligned half-cycle phenomenon. The center of the cloud pattern is a bright spot (the center of the cloud pattern is a circular bright ridge). Alternating light and dark cloud stripes are formed around this bright spot.

[0143] The number of cloud-like stripes in the image is counted along the diagonal direction passing through the center of the surface of lithium battery 2, resulting in a number of bright stripes m = 13 and n = 10.

[0144] The lithium battery warpage ω is calculated to be 1725 μm based on the above formula.

[0145] The moiré pattern analyzer provided by this invention can detect minute displacement changes and accurately measure subtle warping on the surface of the lithium battery 2. This is crucial for lithium batteries 2, which require high flatness, as it helps to identify minute deformation issues, provides accurate measurement data for the production process, and ensures the quality and performance of the lithium battery 2.

[0146] The moiré meter can measure the entire surface of the lithium battery 2 to obtain all warpage information, which helps to discover local warpage problems and the overall deformation trend, providing more comprehensive information for the quality control of the lithium battery 2.

[0147] The method of measuring the surface warpage of lithium battery 2 using the aforementioned moiré meter can acquire a large amount of measurement data in a short time, improving measurement efficiency. For mass-produced lithium batteries 2, this allows for rapid testing of a large number of products, timely detection of quality problems, and improved production efficiency and product quality. Simultaneously, the measurement method is simple to operate, reducing the technical requirements for operators and improving the operability and efficiency of the measurement.

[0148] Furthermore, the measurement method can be equipped with corresponding data analysis software, which can quickly process and analyze the obtained cloud pattern to extract the deformation information of the lithium battery 2 surface.

[0149] The moiré meter is not limited to measuring the surface warp of lithium battery 2; it can also be applied to measuring the surface warp of other objects, especially larger objects.

[0150] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A moire for measuring the warpage of a lithium battery, characterized in that, The cloud pattern instrument includes: A cloud-patterned sheet, the cloud-patterned sheet being placed horizontally on the surface of a lithium battery; The mottled sheet comprises: a mottled sheet film and optical glass, wherein the edge of the mottled sheet film is adhered to the optical glass; A camera, positioned above the cloud pattern sheet, is used to photograph the cloud pattern formed on the cloud pattern sheet; A light source is positioned above the cloud-patterned sheet to emit light and illuminate the cloud-patterned sheet; The centers of the camera, the light source, and the mottled pattern are located on the same plane.

2. The moire device of claim 1, wherein, The angle formed by the line connecting the center of the light source and the center of the cloud pattern piece and the normal at the center of the cloud pattern piece is α, where α = 45°.

3. The moire device of claim 1, wherein, The angle formed by the line connecting the center of the camera and the center of the mottled pattern and the normal at the center of the mottled pattern is β, where β = 0°.

4. The cloud instrument of claim 1, wherein, The gratings on the cloud-patterned sheet are arranged in concentric circles.

5. The cloud instrument of claim 1, wherein, The cloud-patterned piece is 15-35cm long and 15-35cm wide.

6. The cloud instrument of claim 1, wherein, The cloud-patterned sheet further includes a protective layer, which is disposed on the surface of the cloud-patterned sheet and is transparent.

7. The cloud instrument of claim 1, wherein, The grating spacing ε on the mottled film is 120-180μm.

8. The cloud instrument of claim 1, wherein, The light source is a spotlight.

9. The cloud instrument of claim 1, wherein, The cloud pattern instrument also includes: The first bracket is used to mount the camera; The second bracket is used to mount the light source.

10. The moire device of claim 1, wherein, The moiré pattern analyzer also includes a processor for outputting measurement results.

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