Patent Description:
In the related art, the battery cell is an important part of the lithium battery, in which the outer surface of the case of the battery cell is clad with a separation film, and the requirements for the appearance of the outer separation film of the case of the battery cell are very high, so it is necessary to perform the inspection of appearance defects of the film-clad battery cell.

At present, the appearance defects of the battery cell are detected by detection apparatuses, but the existing detection apparatuses can only detect the defects outside the film of the film-clad battery cell, but cannot detect the defects inside the film of the film-clad battery cell. For example, foreign matter particles and air bubbles inside the film of the film-clad battery cell cannot be detected, and if there are slight pits outside the film of the film-clad battery cell, the pits are not easy to be detected by the detection apparatuses.

<CIT> relates to a system for inspecting the appearance of an object such as a battery for an electric vehicle.

The present application is intended to at least solve one of the technical problems existing in the prior art. For this purpose, one of the objectives of the present application is to propose a battery cell appearance defect detection apparatus, which can accurately detect the defects inside and outside the film of the film-clad battery cell.

The present application further proposes a detection device.

The current invention provides a film-clad battery cell appearance defect detection apparatus according to claim <NUM>.

In the above technical solution, by arranging a first detection assembly, a second detection assembly, and a control assembly, foreign matter particles and air bubbles inside the outer film of the battery cell can be detected, and foreign matter particles or air bubbles can also be accurately distinguished, and pits on the surface of the outer film of the battery cell can also be accurately detected, thereby accurately detecting defects inside and outside the film of the film-clad battery cell.

In the above technical solution, by setting the first light and the second light to be both infrared scanning light, the detection performance of the battery cell appearance defect detection apparatus can be ensured, thereby ensuring that the battery cell appearance defect detection apparatus can accurately detect the defects inside and outside the film of the film-clad battery cell.

In the above technical solution, by setting <NUM> ≤ λ ≤ <NUM>, the wavelength of the first light and the wavelength of the second light can be made to be appropriate, and it can be ensured that the first light can pass through the outer film of the battery cell, and when the second light irradiates the detection surface, it can be ensured that the battery cell appearance defect detection apparatus can accurately detect pits on the surface of the battery cell.

In some embodiments, the first included angle is α, which satisfies the relational expression: <NUM>° ≤ α ≤ <NUM>°.

In the above technical solution, by setting <NUM>° ≤ α ≤ <NUM>°, it is possible to detect foreign matter particles and air bubbles inside the outer film of the battery cell more accurately, and also to distinguish between foreign matter particles and air bubbles.

In some embodiments, the second included angle is β, and <NUM>° ≤ β ≤ <NUM>°.

In the above technical solution, by setting <NUM>° ≤ β ≤ <NUM>° , pits on the surface of the battery cell can be detected more accurately.

In some embodiments, the first image collector is constructed as a line scan camera, and the position on the detection surface irradiated by the scanning line of the first image collector coincides with the position on the detection surface irradiated by the first light.

In the above technical solution, by arranging the position on the detection surface irradiated by the scanning line of the first image collector to coincide with the position on the detection surface irradiated by the first light, the first image collector can accurately collect the first image of the position of the battery cell irradiated by the first light, and the control assembly can accurately determine the foreign matter particles and air bubbles inside the outer film of the battery cell according to the first image.

In some embodiments, the second image collector is constructed as a line scan camera, and the position on the detection surface irradiated by the scanning line of the second image collector coincides with the position on the detection surface irradiated by the second light.

In the above technical solution, by arranging the position on the detection surface irradiated by the scanning line of the second image collector to coincide with the position on the detection surface irradiated by the second light, the second image collector can accurately collect the second image of the position of the battery cell irradiated by the second light, and the control assembly can accurately determine whether pits exist on the surface of the battery cell according to the second image.

In some embodiments, the first detection assembly and the second detection assembly are located on the same side of the detection surface.

In the above technical solution, when the battery cell appearance defect detection apparatus detects appearance defects of the battery cell, the first detection assembly and the second detection assembly are located on the same side of the detection surface, which facilitates the arrangement of the battery cell appearance defect detection apparatus and can simplify the structure of the battery cell appearance defect detection apparatus.

In some embodiments, a first light region on the detection surface irradiated by the first light is misaligned with a second light region on the detection surface irradiated by the second light.

In the above technical solution, by arranging the first light region on the detection surface irradiated by the first light to be misaligned with the second light region on the detection surface irradiated by the second light, it is possible to avoid the coinciding of the first light region on the detection surface irradiated by the first light and the second light region on the detection surface irradiated by the second light, and to prevent the first detection assembly and the second detection assembly from interfering with each other, thereby improving the detection accuracy of the battery cell appearance defect detection apparatus.

In some embodiments, along a direction perpendicular to the detection surface, the spacing distance between a light source light-emitting surface of the first light source and the detection surface is D1, and the spacing distance between a light source light-emitting surface of the second light source and the detection surface is D2, which satisfy the relational expression: D2 < D1.

In the above technical solution, by setting D2 < D1, it is possible to make the first light source to be misaligned with the second light source, thus avoiding mutual interference between the first light source and the second light source.

In some embodiments, the first light source and the second light source respectively emit light from different directions to the detection surface.

In the above technical solution, by setting the first light source and the second light source to emit light from different directions to the detection surface, it is possible to avoid coinciding of the first light and the second light.

In some embodiments, along a direction perpendicular to the detection surface, the spacing distance between a light source light-emitting surface of the first light source and the detection surface is D1, which satisfies the relational expression: <NUM> < D1 < <NUM>; and/or
along a direction perpendicular to the detection surface, the spacing distance between a light source light-emitting surface of the second light source and the detection surface is D2, which satisfies the relational expression: <NUM> < D2 < <NUM>.

In the above technical solution, by setting <NUM> < D1 < <NUM>, it is possible to make the spacing distance between the light source light-emitting surface of the first light source and the detection surface to be appropriate, which can ensure that the first light can pass through the outer film of the battery cell, and by setting <NUM> < D2 < <NUM>, the accurate detection of pits on the surface of the battery cell can be ensured, thereby improving the precision of detection of the battery cell appearance defect detection apparatus.

In some embodiments, <NUM> ≤ D1 ≤ <NUM>.

In the above technical solution, by setting <NUM> ≤ D1 ≤ <NUM>, it is possible to make the spacing distance between the light source light-emitting surface of the first light source and the detection surface to be more appropriate, which can ensure that the first light can pass through the outer film of the battery cell, and ensuring that the battery cell appearance film of the battery cell.

In some embodiments, <NUM> ≤ D2 ≤ <NUM>.

In the above technical solution, by setting <NUM> ≤ D2 ≤ <NUM>, pits on the surface of the battery cell can be detected more accurately, thus further improving the precision of detection of the battery cell appearance defect detection apparatus.

In some embodiments, the battery cell appearance defect detection apparatus is suitable for appearance detection of the battery cell that is moving.

In the above technical solution, the appearance detection of the battery cell that is moving by the battery cell appearance defect detection apparatus can complete the detection of appearance defects of the battery cell during the movement of the battery cell, which enhances the speed of detection and can improve the efficiency of detection of the battery cell.

In some embodiments, a first light region on the detection surface irradiated by the first light is parallel to a second light region on the detection surface irradiated by the second light.

In the above technical solution, by arranging the first light region on the detection surface irradiated by the first light to be parallel to the second light region on the detection surface irradiated by the second light, it is possible to avoid the intersection of the first light region on the detection surface irradiated by the first light and the second light region on the detection surface irradiated by the second light, and to ensure respective detection performance of the first detection assembly and the second detection assembly, thereby improving the detection accuracy of the battery cell appearance defect detection apparatus.

In some embodiments, along the direction of extension of a first light region on the detection surface irradiated by the first light, the width of the detection surface is L1 and the length of the first light region is L2, which satisfy the relational expression: L1 ≤ L2.

In the above technical solution, by setting L1 ≤ L2, it is ensured that the first light can scan the entire detection surface during the movement of the battery cell, thus avoiding the occurrence of a missed detection of a certain region of the detection surface.

In some embodiments, along the direction of extension of a second light region on the detection surface irradiated by the second light, the width of the detection surface is L3 and the length of the second light region is L4, which satisfy the relational expression: L3 ≤ L4.

In the above technical solution, by setting L3 ≤ L4, it is ensured that the second light can scan the entire detection surface, thus avoiding the occurrence of a missed detection of a certain region of the detection surface.

In some embodiments, the first image collector and/or the second image collector are/is constructed as a line scan camera, and the gray scale value of an image generated through collection by the line scan camera is <NUM>-<NUM>.

In the above technical solution, by setting the gray scale value of the image generated through collection by the line scan camera to be in <NUM>-<NUM>, the contrast of the image can be made appropriate, so that the characteristic defects inside and outside the film of the film-clad battery cell are obvious.

In some embodiments, the battery cell appearance defect detection apparatus further comprises: an angle detection apparatus for detecting an included angle between the first light and the detection surface and an included angle between the second light and the detection surface.

In the above technical solution, by providing the angle detection apparatus, the included angle between the first light and the detection surface and the included angle between the second light and the detection surface can be detected, thus facilitating the determination of whether the second included angle is less than the first included angle.

In some embodiments, the control assembly is communicatively connected to both the first light source and the second light source, and the control assembly is used to control the turning on or off of the first light source, the second light source, the first image collector, and the second image collector.

In the above technical solution, by communicatively connecting the control assembly to both the first light source and the second light source, the control assembly controls the first light source, the second light source, the first image collector, and the second image collector to turn on when it is necessary to detect appearance defects of the battery cell, and controls the first light source, the second light source, the first image collector, and the second image collector to turn off when it is not necessary to detect appearance defects of the battery cell, thus avoiding waste of electricity by the battery cell appearance defect detection apparatus.

In a second aspect, embodiments of the present application further provide a detection device comprising a battery cell appearance defect detection apparatus mentioned above.

In the above technical solution, there are a plurality of said battery cell appearance defect detection apparatuses, the plurality of said battery cell appearance defect detection apparatuses being used for correspondingly detecting a plurality of said detection surfaces of the battery cell.

In the above technical solution, by means of a plurality of said battery cell appearance defect detection apparatuses correspondingly detecting a plurality of said detection surfaces of the battery cell, the efficiency of detection of appearance defects of the battery cell can be improved.

Additional aspects and advantages of the present application will be given in part in the following description, and will become apparent in part from the following description, or be learned through the practice of the present application.

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 accompanying drawings, in which:.

Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout indicate the same or similar components or components having the same or similar functions. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application only and are not to be construed as limiting the present application.

To make the objective, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application. Obviously, the embodiments described are some of rather than all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort fall within the protection scope of the present application.

Unless otherwise defined, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs. The terms used in the specification of the present application are merely for the purpose of describing specific embodiments, but are not intended to limit the present application. The terms "comprising" and "having" and any variations thereof in the specification and the claims of the present application as well as the foregoing description of the drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc., in the specification and claims of the present application or in the accompanying drawings above are used to distinguish between different objects and are not intended to describe a particular order or relationship of precedence.

Reference to "an embodiment" in the present application means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

In the description of the present application, it should be noted that the terms "mounting", "connecting", "connection" and "attachment" should be understood in a broad sense, unless otherwise explicitly specified or defined. For example, it may be a fixed connection, a detachable connection, or an integrated connection; and it may be a direct connection or an indirect connection through an intermediate medium, or may be a communication between the interior of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

In the present application, the term "and/or" is only an association relationship for describing associated objects, indicating that three relationships may exist. For example, A and/or B may represent three situations: A exists alone, both A and B exist, and B exists alone. In addition, the character "/" in the present application generally means that the associated objects before and after it are in an "or" relationship.

In the embodiments of the present application, the same reference numerals indicate the same parts and, for the sake of brevity, the detailed description of the same parts is omitted in the different embodiments. It should be understood that the dimensions such as the thickness, length, and width of various components in the embodiments of the present application shown in the accompanying drawings, as well as the dimensions such as the overall thickness, length, and width of the integrated apparatus are illustrative only and shall not constitute any limitation on the present application.

In the present application, battery cell <NUM> may comprise a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium/lithium-ion battery, a sodium-ion battery, a magnesium-ion battery, or the like, which is not limited in the embodiments of the present application. The battery cell <NUM> may be cylindrical, flat, rectangular, or in other shapes, which is also not limited in the embodiments of the present application. The battery cell <NUM> is generally divided into three types according to encapsulating manners: cylindrical battery cells, rectangular battery cells, and pouch cells, which are not limited in the embodiments of the present application.

The battery cell <NUM> comprises a shell, an electrode assembly, and an electrolyte solution, and the shell is used to accommodate the electrode assembly and the electrolyte solution. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell <NUM> operates mainly relying on movement of metal ions between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet comprises a positive electrode current collector and a positive electrode active material layer, wherein the positive electrode active material layer is coated on a surface of the positive electrode current collector, the part of the positive electrode current collector not coated with the positive electrode active material layer protrudes from the part of the positive electrode current collector already coated with the positive electrode active material layer, and the part of the positive electrode current collector not coated with the positive electrode active material layer serves as a positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer is coated on a surface of the negative electrode current collector, the part of the negative electrode current collector not coated with the negative electrode active material layer protrudes from the part of the negative electrode current collector already coated with the negative electrode active material layer, and the part of the negative electrode current collector not coated with the negative electrode active material layer serves as a negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that no fusing occurs when a large current passes, there are a plurality of positive electrode tabs which are laminated together, and there are a plurality of negative electrode tabs which are laminated together.

The separator may be made from polypropylene (PP), polyethylene (PE), or the like. In addition, the electrode assembly may be of a wound structure or a laminated structure, which is not limited in the embodiments of the present application.

The inventor found that there is a separation film bonded on the outer surface of the shell of the battery cell, and during the production and detection of the battery cell, the appearance defects of the battery cell are inspected by a detection apparatus, but the existing detection apparatuses can only detect defects on the outer surface of the separation film, but not defects inside the film of the film-clad battery cell. In other words, defects between the separation film and the shell of the battery cell cannot be detected. For example, foreign matter particles and air bubbles between the separation film and the shell of the battery cell cannot be detected. Moreover, if there are slight pits on the surface of the battery cell, it is not easy for the pits to be detected by the existing detection apparatuses.

In addition, the existing battery cell appearance defect inspection identifies appearance defects of a battery cell by means of manual visual inspection and manual touch, so the speed of detection of the existing way of detecting appearance defects of the battery cell is low, resulting in low efficiency of detection; if there are foreign matter particles inside the separation film, the manual touch may lead to the breakage of the separation film, thus causing secondary damage to the battery cell; and at the same time, if there are slight pits on the surface of the battery cell, it is not easy for the pits to be detected.

Based on the above considerations, in order to solve the problem of accurately detecting appearance defects of the battery cell <NUM>, the inventor, after research, has designed a battery cell appearance defect detection apparatus <NUM>. The battery cell appearance defect detection apparatus <NUM>, by arranging a first detection assembly <NUM>, a second detection assembly <NUM>, and a control assembly, can detect foreign matter particles and air bubbles inside the outer film of the battery cell <NUM>, and can also accurately distinguish between foreign matter particles and air bubbles, and can also accurately detect pits on the surface of the outer film of the battery cell <NUM>, thereby accurately detecting defects inside and outside the film of the film-clad battery cell <NUM>. Moreover, compared with the manual inspection approach, using the battery cell appearance defect detection apparatus <NUM> of the present application to detect the battery cell <NUM>, it is possible to enhance the speed of detection, improve the efficiency of detection, and avoid causing secondary damage to the battery cell <NUM>, and at the same time, slight pits existing on the outer surface of the film of the battery cell <NUM> can be accurately detected.

The battery cell appearance defect detection apparatus <NUM> according to embodiments of the present application will be described with reference to <FIG>. The present application is illustrated taking the direction of arrangement of the battery cell <NUM> and the battery cell appearance defect detection apparatus <NUM> in <FIG> as an example. The battery cell appearance defect detection apparatus <NUM> comprises a first detection assembly <NUM>, a second detection assembly <NUM>, and a control assembly. The first detection assembly <NUM> comprises a first image collector <NUM> and a first light source <NUM>, wherein the first light source <NUM> is used to emit first light <NUM> toward a detection surface <NUM> of a battery cell <NUM>, the detection surface <NUM> being the surface of the battery cell <NUM> that needs to be detected. The first light <NUM> is adapted to pass through the outer film of the battery cell <NUM> (i.e., the separation film in the above embodiment, which may also be a blue film on the outer surface of the case of the battery cell <NUM>), and the first light <NUM> forms a first included angle α with the detection surface <NUM>, and the first image collector <NUM> is used to collect a first image of a position of the battery cell <NUM> irradiated by the first light <NUM>.

The second detection assembly <NUM> comprises a second image collector <NUM> and a second light source <NUM>, wherein the second light source <NUM> is used to emit second light <NUM> toward the detection surface <NUM>, the second light <NUM> forming a second included angle with the detection surface <NUM>, and the second image collector <NUM> is used to collect a second image of a position of the battery cell <NUM> irradiated by the second light <NUM>, with the second included angle β being less than the first included angle α. The control assembly may be an industrial personal computer, and the control assembly is connected respectively to the first image collector <NUM> and the second image collector <NUM>, or it can be understood that the control assembly is communicatively connected to both the first image collector <NUM> and the second image collector <NUM>, and the control assembly is constructed to detect appearance defects of the battery cell <NUM> according to the first image and the second image. The appearance defects of the film-clad battery cell <NUM> comprise defects between the outer film and the shell of the battery cell <NUM> and defects on the outer film, and it is to be noted that the defects between the outer film and the shell of the battery cell <NUM> may include defects such as foreign matter, air bubbles, etc., between the outer film and the shell of the battery cell <NUM>, and the defects on the outer film may include defects such as pits on the outer film, matter on the outer film, damages on the outer film, scratches on the outer film, etc. The present application is illustrated by taking the detection of foreign matter and air bubbles between the outer film and the shell of the battery cell <NUM> as well as pits on the outer film as an example.

Here, the battery cell appearance defect detection apparatus <NUM> of the present application can perform detection of appearance defects of a moving film-clad battery cell <NUM>, and the battery cell appearance defect detection apparatus <NUM> can also perform detection of appearance defects of an unmoving film-clad battery cell <NUM>, and the present application is illustrated taking an example where the battery cell appearance defect detection apparatus <NUM> performs detection of appearance defects of a moving film-clad battery cell <NUM>.

Specifically, when the film-clad battery cell <NUM> flows past the battery cell appearance defect detection apparatus <NUM>, the first image collector <NUM>, the first light source <NUM>, the second image collector <NUM>, and the second light source <NUM> are turned on for operation, wherein the first light source <NUM> emits first light <NUM> toward the detection surface <NUM> of the battery cell <NUM>, the first light <NUM> passing through the outer film of the battery cell <NUM> and the first light <NUM> forming a first included angle α with the detection surface <NUM>, and the first image collector <NUM> performs image scanning to collect a first image of a position of the battery cell <NUM> that is irradiated by the first light <NUM>. At the end of the scanning, under the action of the first light <NUM>, at the position with foreign matter particles, because the first light <NUM> cannot pass through the foreign matter particles, the first image appears dark in the middle and bright around, so that the specific position of the foreign matter particles can be located; while at the position without foreign matter but with air bubbles, the first image appears brighter, so that the specific position of the air bubbles can be located; while in the area without foreign matter particles or air bubbles, the first image appears dark in color. The first image collector <NUM> transmits the collected first image to the control assembly, and a pre-tuned AI algorithm in the control assembly detects whether there are foreign matter particles and air bubbles inside the film of the battery cell <NUM>, and the AI algorithm distinguishes between the air bubbles inside the film and the foreign matter inside the film based on different forms.

In addition, the second light source <NUM> emits second light <NUM> toward the detection surface <NUM> of the battery cell <NUM>, the second light <NUM> forming a second included angle β with the detection surface <NUM> to detect pits on the surface of the battery cell <NUM> in a manner that mimics tilted observation by the human eye, and the second image collector <NUM> performs image scanning to collect a second image of a position of the battery cell <NUM> that is irradiated by the second light <NUM>. At the end of the scanning, under the action of the second light <NUM>, positions with and without pits will show distinctly different features on the second image. After the second image collector <NUM> transmits the collected second image to the control assembly, the pre-tuned AI algorithm in the control assembly detects whether there are pits on the outer surface of the film of the film-clad battery cell <NUM>.

In the above technical solution, by arranging the first detection assembly <NUM>, the second detection assembly <NUM>, and the control assembly, it is possible to detect appearance defects of the film-clad battery cell <NUM> during the movement of the battery cell <NUM>, and by detecting the appearance of the battery cell <NUM> in such a contactless and non-stop manner, it is possible to improve the efficiency of detection without causing secondary damage to the battery cell <NUM> due to manual contact. Moreover, by making the second included angle β to be smaller than the first included angle α, the battery cell appearance defect detection apparatus <NUM> not only can accurately detect whether there are foreign matter particles and bubbles inside the outer film of the battery cell <NUM>, but also can accurately distinguish between foreign matter particles and air bubbles, and also can accurately detect pits on the outer surface of the film of the battery cell <NUM>, and also can detect slight pits on the outer surface of the film of the battery cell <NUM>, thereby accurately detecting defects inside and outside the film of the film-clad battery cell <NUM>. Moreover, the battery cell appearance defect detection apparatus <NUM> of the present application is highly automated and simple to operate.

In some embodiments, as shown in <FIG>, the first included angle is α, which satisfies the relational expression: <NUM>°≤α≤<NUM>°. For example, the first included angle α is <NUM>°, <NUM>°, <NUM>° and other values, but the present application is not limited in this regard, and the specific value of the first included angle α can be reasonably selected and set according to the actual situation. By setting <NUM>°≤α≤<NUM>°, it is possible to make the angle between the first light <NUM> and the detection surface <NUM> appropriate, and to ensure that the first image collector <NUM> can collect a clear first image after the first light <NUM> irradiates the detection surface <NUM>. After receiving the first image, the control assembly can more accurately detect whether there are foreign matter particles and air bubbles between the shell and the outer film of the battery cell <NUM> (i.e., on the inner side of the film), and, when there are foreign matter particles and air bubbles on the inner side of the outer film of the battery cell <NUM>, the foreign matter particles and air bubbles can be accurately distinguished from each other, and the position of the foreign matter particles and the position of the air bubbles can also be accurately located.

In some embodiments, as shown in <FIG>, the second included angle is β, <NUM>°≤β≤<NUM>°. For example, the second included angle β is <NUM>°, <NUM>°, <NUM>° and other values, but the present application is not limited in this regard, and the specific value of the second included angle β can be reasonably selected and set according to the actual situation. By setting <NUM>°≤β≤<NUM>°, it is possible to make the angle between the second light <NUM> and the detection surface <NUM> appropriate, and to ensure that the second image collector <NUM> can collect a clear second image after the second light <NUM> irradiates the detection surface <NUM>. After receiving the second image, the control assembly can more accurately detect whether there are pits on the outer surface of the film of the film-clad battery cell <NUM>, and, when there are pits on the outer surface of the film of the battery cell <NUM>, the position of the pits can be accurately located.

In some embodiments, the control assembly is communicatively connected to both the first light source <NUM> and the second light source <NUM>, and the control assembly is used to control the turning on or off of the first light source <NUM>, the second light source <NUM>, the first image collector <NUM>, and the second image collector <NUM>. Here, by communicatively connecting the control assembly to both the first light source <NUM> and the second light source <NUM>, the control assembly controls the first light source <NUM>, the second light source <NUM>, the first image collector <NUM>, and the second image collector <NUM> to turn on when it is necessary to detect appearance defects of the battery cell <NUM>, and controls the first light source <NUM>, the second light source <NUM>, the first image collector <NUM>, and the second image collector <NUM> to turn off when it is not necessary to detect appearance defects of the battery cell <NUM>, thus avoiding waste of electricity by the battery cell appearance defect detection apparatus <NUM>.

According to the invention, as shown in <FIG>, the first light <NUM> and the second light <NUM> are both infrared scanning light. Among them, both the first light source <NUM> and the second light source <NUM> are set as infrared light sources, and the light emitted from the infrared light sources is infrared scanning light. By setting both the first light <NUM> and the second light <NUM> to be infrared scanning light, the first light <NUM> can pass through the outer film of the battery cell <NUM>, the detection performance of the battery cell appearance defect detection apparatus <NUM> can be ensured, thereby ensuring that the battery cell appearance defect detection apparatus <NUM> can accurately detect the defects on the inner side of the film and outside the film of the film-clad battery cell <NUM>. Moreover, for foreign matter particles inside the film with a height of <NUM> or less, the first image collector <NUM> can collect a clear first image by scanning with infrared scanning light, so that the position of foreign objects can be clearly located.

According to the invention, the wavelength of the first light <NUM> and the wavelength of the second light <NUM> are both satisfy the relational expression: <NUM> ≤ λ ≤ <NUM>, for example, λ is <NUM>, <NUM>, <NUM>, and other values. By setting <NUM> ≤ λ ≤ <NUM>, it is possible to make the wavelength of the first light <NUM> and/or the wavelength of the second light <NUM> appropriate, and to ensure that the first light <NUM> can pass through the outer film of the battery cell <NUM>, and ensure that the first image collector <NUM> can collect a clear first image. After receiving the first image, the control assembly can more accurately detect whether there are foreign matter particles and air bubbles on the inner side of the outer film of the film-clad battery cell <NUM>, and, when there are foreign matter particles and air bubbles on the inner side of the outer film of the battery cell <NUM>, the foreign matter particles and air bubbles can be accurately distinguished from each other, and the position of the foreign matter particles and the position of the air bubbles can also be accurately located. In addition, it is possible to ensure that the second image collector <NUM> can collect a clear second image after the second light <NUM> irradiates the detection surface <NUM>. After receiving the second image, the control assembly can more accurately detect whether there are pits on the outer film of the film-clad battery cell <NUM>, and, when there are pits on the outer surface of the film of the battery cell <NUM>, the position of the pits can be accurately located, thus ensuring that the battery cell appearance defect detection apparatus <NUM> can accurately detect the pits on the outer surface of the film of the battery cell <NUM>.

In some embodiments, the first image collector <NUM> is constructed as a line scan camera, for example, the first image collector <NUM> is constructed as a 2D line scan camera, a position on the detection surface <NUM> irradiated by a scanning line of the first image collector <NUM> coinciding with a position on the detection surface <NUM> irradiated by the first light <NUM>. Here, by arranging the position on the detection surface <NUM> irradiated by the scanning line of the first image collector <NUM> to coincide with the position on the detection surface <NUM> irradiated by the first light <NUM>, the first image collector <NUM> can accurately collect the first image of the position of the battery cell <NUM> irradiated by the first light <NUM>, and the control assembly can accurately determine the foreign matter particles and the air bubbles on the inner side of the outer film of the battery cell <NUM> according to the first image, and when there are foreign matter particles and air bubbles on the inner side of the outer film of the battery cell <NUM>, they can be accurately detected by the battery cell appearance defect detection apparatus <NUM>. Moreover, by arranging the first image collector <NUM> as a line scan camera, it can be ensured that the first image collector <NUM> can perform image scanning on the battery cell <NUM> that is moving, thereby realizing the effect that the battery cell appearance defect detection apparatus <NUM> can perform appearance detection of the battery cell <NUM> that is moving.

In some embodiments, the second image collector <NUM> is constructed as a line scan camera, for example, the second image collector <NUM> is constructed as a 2D line scan camera, a position on the detection surface <NUM> irradiated by a scanning line of the second image collector <NUM> coinciding with a position on the detection surface <NUM> irradiated by the second light <NUM>. By arranging the position on the detection surface <NUM> irradiated by the scanning line of the second image collector <NUM> to coincide with the position on the detection surface <NUM> irradiated by the second light <NUM>, the second image collector <NUM> can accurately collect the second image of the position of the battery cell <NUM> irradiated by the second light <NUM>, and the control assembly can accurately determine whether there are pits on the outer surface of the film of the battery cell <NUM> according to the second image; and when there are pits on the outer surface of the film of the battery cell <NUM>, the pits can be accurately detected by the battery cell appearance defect detection apparatus <NUM>. Moreover, by arranging the second image collector <NUM> as a line scan camera, it can be ensured that the second image collector <NUM> can perform image scanning on the battery cell <NUM> that is moving, thereby realizing the effect that the battery cell appearance defect detection apparatus <NUM> can perform the appearance detection of the battery cell <NUM> that is moving.

In some embodiments, as shown in <FIG>, the first detection assembly <NUM> and the second detection assembly <NUM> are located on the same side of the detection surface <NUM>. Here, as shown in <FIG>, the battery cell <NUM> is illustrated with the direction of arrangement in <FIG> as an example. When the upper surface of the battery cell <NUM> is the detection surface <NUM>, the first detection assembly <NUM> and the second detection assembly <NUM> are located over the upper side of the detection surface <NUM>, the first light source <NUM>, the second light source <NUM>, the first image collector <NUM>, and the second image collector <NUM> are all opposite and spaced apart from the detection surface <NUM>, and the scanning line of the first image collector <NUM> and the scanning line of the second image collector <NUM> can both be perpendicular to the detection surface <NUM>. When the battery cell appearance defect detection apparatus <NUM> detects appearance defects of the battery cell <NUM>, the first detection assembly <NUM> and the second detection assembly <NUM> are located on the same side of the detection surface <NUM>, which facilitates the arrangement of the battery cell appearance defect detection apparatus <NUM> and can simplify the structure of the battery cell appearance defect detection apparatus <NUM>. Moreover, this is also convenient for the first light <NUM> of the first light source <NUM> and the second light <NUM> of the second light source <NUM> to irradiate the detection surface <NUM>, and is also convenient for the scanning line of the first image collector <NUM> and the scanning line of the second image collector <NUM> to irradiate the detection surface <NUM>.

In some embodiments, as shown in <FIG> and <FIG>, along the direction of movement of the battery cell <NUM>, a first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> is misaligned with a second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM>. Here, as shown in <FIG>, an illustration is provided taking the movement of the battery cell <NUM> along the left and right direction in <FIG> as an example. When detecting appearance defects of the battery cell <NUM>, the battery cell <NUM> moves along the left and right direction in <FIG>, and the first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> is misaligned with the second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM>. By arranging the first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> to be misaligned with the second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM>, it is possible to avoid the coinciding of the first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> and the second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM>, and it is possible to prevent the first detection assembly <NUM> and the second detection assembly <NUM> from interfering with each other, thereby improving the detection accuracy of the battery cell appearance defect detection apparatus <NUM>.

In some embodiments, as shown in <FIG>, the first light source <NUM> and the second light source <NUM> emit light from different directions to the detection surface <NUM>, so that it is possible to avoid coinciding of the first light <NUM> and the second light <NUM>. Further, as shown in <FIG>, along the direction of movement of the battery cell <NUM>, the first light source <NUM> is disposed near the left side of the battery cell <NUM>, the second light source <NUM> is disposed near the right side of the battery cell <NUM>, the first light source <NUM> is inclined toward the right side of the battery cell <NUM> to emit the first light <NUM> toward the detection surface <NUM>, and the second light source <NUM> is inclined toward the left side of the battery cell <NUM> to emit the second light <NUM> toward the detection surface <NUM>, which is convenient for the first light <NUM> and second light <NUM> to irradiate the detection surface <NUM> of the battery cell <NUM>.

In some embodiments, as shown in <FIG>, along the direction perpendicular to the detection surface <NUM>, the vertical spacing distance between the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> is D1, and the vertical spacing distance between the light source light-emitting surface of the second light source <NUM> and the detection surface <NUM> is D2, which satisfy the relational expression: D2 < D1. It is to be noted that when the battery cell appearance defect detection apparatus <NUM> and the battery cell <NUM> are placed in the direction as shown in <FIG>, the vertical spacing distance between the lowermost end of the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> is D1, and the vertical spacing distance between the lowermost end of the light source light-emitting surface of the second light source <NUM> and the detection surface <NUM> is D2. Here, as shown in <FIG>, along the up and down direction, if the spacing distance between the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> is equal to the spacing distance between the light source light-emitting surface of the second light source <NUM> and the detection surface <NUM>, when the first light source <NUM> is inclined toward the right side of the battery cell <NUM> to emit the first light <NUM> toward the detection surface <NUM> and the second light source <NUM> is inclined toward the left side of the battery cell <NUM> to emit the second light <NUM> toward the detection surface <NUM>, in the case where the first included angle α and the second included angle β are of certain angles, there is a risk of intersection between the first light <NUM> and the second light <NUM>.

Therefore, by arranging the spacing distance between the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> to be smaller than the spacing distance between the light source light-emitting surface of the second light source <NUM> and the detection surface <NUM>, the first light source <NUM> and the second light source <NUM> can be made misaligned, thus avoiding interference between the first light source <NUM> and the second light source <NUM> and avoiding intersection of the first light <NUM> with the second light <NUM>, which is conducive to making the region on the detection surface <NUM> irradiated by the first light <NUM> to be misaligned with the region on the detection surface <NUM> irradiated by the second light <NUM>.

In some embodiments, as shown in <FIG>, along the direction perpendicular to the detection surface <NUM>, the spacing distance between the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> is D1, which satisfies the relational expression: <NUM> < D1 < <NUM>, for example, D1 is <NUM>, <NUM>, <NUM>, <NUM> and other values, but the present application is not limited in this regard, and the spacing distance between the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> is reasonably selected and set according to the actual situation; and/or along the direction perpendicular to the detection surface <NUM>, the spacing distance between the light source light-emitting surface of the second light source <NUM> and the detection surface <NUM> is D2, which satisfies the relational expression: <NUM> < D2 < <NUM>, for example, D2 is <NUM>, <NUM>, <NUM> and other values, but the present application is not limited in this regard, and the spacing distance between the light source light-emitting surface of the second light source <NUM> and the detection surface <NUM> is reasonably selected and set according to the actual situation. By setting <NUM> < D1 < <NUM>, it is possible to make the spacing distance between the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> to be appropriate, which can ensure that the first light <NUM> can pass through the outer film of the battery cell <NUM>, and by setting <NUM> < D2 < <NUM>, the accurate detection of the pits on the outer surface of the film of the battery cell <NUM> by the battery cell appearance defect detection apparatus <NUM> can be ensured, thereby improving the precision of detection of the battery cell appearance defect detection apparatus <NUM>.

In some embodiments, <NUM> < D1 < <NUM>, for example, D1 is <NUM>, <NUM>, <NUM>, <NUM> and other values, but the present application is not limited in this regard, and the spacing distance between the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> is reasonably selected and set according to the actual situation. By setting <NUM> ≤ D1 ≤ <NUM>, it is possible to make the spacing distance between the light source light-emitting surface of the first light source <NUM> and the detection surface <NUM> to be more appropriate, which can ensure that the first light <NUM> can pass through the outer film of the battery cell <NUM>, thus enabling the first image collector <NUM> to collect a clearer first image, and ensuring that the battery cell appearance defect detection apparatus <NUM> can detect foreign matter particles and air bubbles inside the outer film of the battery cell <NUM>.

In some embodiments, <NUM> < D2 < <NUM>, for example, D2 is <NUM>, <NUM>, <NUM>, <NUM> and other values, but the present application is not limited in this regard, and the spacing distance between the light source light-emitting surface of the second light source <NUM> and the detection surface <NUM> is reasonably selected and set according to the actual situation. By setting <NUM> ≤ D2 ≤ <NUM>, the second image collector <NUM> can enabled to collect a clearer second image, detect pits on the outer surface of the outer film of the battery cell <NUM> more accurately, thus further improving the precision of detection of the battery cell appearance defect detection apparatus <NUM>.

In some embodiments, the battery cell appearance defect detection apparatus <NUM> is adapted to perform appearance detection of the battery cell <NUM> that is moving, and it can also be understood that the battery cell appearance defect detection apparatus <NUM> can detect appearance defects of the battery cell <NUM> during the movement of the battery cell <NUM>. Here, the battery cell appearance defect detection apparatus <NUM> can be disposed on the detection device, and when the battery cell <NUM> moves on the detection device and the battery cell <NUM> flows past the battery cell appearance defect detection apparatus <NUM>, the battery cell appearance defect detection apparatus <NUM> can complete the detection of appearance defects of the battery cell <NUM> during the movement of the battery cell <NUM>, thus enhancing the speed of inspection, which can improve the efficiency of detection of the battery cell <NUM>.

In some embodiments, as shown in <FIG>, a first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> is parallel to a second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM>. By arranging the first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> to be parallel to the second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM>, it is possible to avoid intersection of the first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> with the second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM>, and to prevent the second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM> from interfering with the first image collector <NUM>, thus ensuring that the first image collector <NUM> collects a clear first image; and also to prevent the first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> from interfering with the second image collector <NUM>, thus ensuring that the second image collector <NUM> collects a clear second image, which can ensure the respective detection performance of the first detection assembly <NUM> and the second detection assembly <NUM>, thereby improving the detection accuracy of the battery cell appearance defect detection apparatus <NUM>.

In some embodiments, as shown in <FIG>, along the direction of extension of the first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM>, the width of the detection surface <NUM> is L1, and the length of the first light region <NUM> on the detection surface <NUM> irradiated by the first light <NUM> is L2, which satisfy the relational expression: L1 ≤ L2. When the battery cell <NUM> flows past the battery cell appearance defect detection apparatus <NUM>, it can also be understood that, during the movement of the battery cell <NUM>, by setting L1 ≤ L2, it can be ensured that the first light <NUM> can scan the entire detection surface <NUM> and avoid the occurrence of missed detection of a certain region of the detection surface <NUM>, thus ensuring that the first image collector <NUM> collects the image information of the entire detection surface <NUM>.

In some embodiments, as shown in <FIG>, along the direction of extension of the second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM>, the width of the detection surface <NUM> is L3, and the length of the second light region <NUM> on the detection surface <NUM> irradiated by the second light <NUM> is L4, which satisfy the relational expression: L3 ≤ L4. When the battery cell <NUM> flows past the battery cell appearance defect detection apparatus <NUM>, it can also be understood that, during the movement of the battery cell <NUM>, by setting L3 ≤ L4, it can be ensured that the second light <NUM> can scan the entire detection surface <NUM> and avoid the occurrence of missed detection of a certain region of the detection surface <NUM>, thus ensuring that the second image collector <NUM> collects the image information of the entire detection surface <NUM>.

In some embodiments, the first image collector <NUM> and/or the second image collector <NUM> are/is constructed as a line scan camera, that is, the first image collector <NUM> or the second image collector <NUM> is constructed as a line scan camera, or both the first image collector <NUM> and the second image collector <NUM> are constructed as line scan cameras, for example, both the first image collector <NUM> and the second image collector <NUM> are constructed as line scan cameras. The gray scale value of an image generated through collection by a line scan camera is <NUM>-<NUM>. For example, the gray scale value of the image generated through collection by the line scan camera is <NUM>, <NUM>, <NUM>, and other values. By setting the gray scale value of the image generated through collection by the line scan camera to be in <NUM>-<NUM>, the contrasts of the first image and the second image can be made appropriate, so that the characteristic defects inside and outside of the film of the film-clad battery cell <NUM> are obvious, and thus after the control assembly receives the first image and the second image, it can accurately detect appearance defects of the battery cell <NUM>, thus improving the product qualification rate.

In some embodiments, the battery cell appearance defect detection apparatus <NUM> further comprises: an angle detection apparatus for detecting an included angle between the first light <NUM> and the detection surface <NUM> and an included angle between the second light <NUM> and the detection surface <NUM>. Here, after the battery cell appearance defect detection apparatus <NUM> is assembled, the included angle between the first light <NUM> and the detection surface <NUM> is detected by the angle detection apparatus, and then it can be determined whether the angle range of the included angle between the first light <NUM> and the detection surface <NUM> is within the angle range of the first included angle α, and when the included angle between the first light <NUM> and the detection surface <NUM> is not within the angle range of the first included angle α, the first light source <NUM> is adjusted so that the included angle between the first light <NUM> emitted by the first light source <NUM> and the detection surface <NUM> is within the angle range of the first included angle α; and the included angle between the second light <NUM> and the detection surface <NUM> is detected by the angle detection apparatus, it can then be determined whether the angle range of the included angle between the second light <NUM> and the detection surface <NUM> is within the angle range of the second included angle β, and when the included angle between the second light <NUM> and the detection surface <NUM> is not within the angle range of the second included angle β, the second light source <NUM> is adjusted so that the included angle between the second light <NUM> emitted by the second light source <NUM> and the detection surface <NUM> is within the angle range of the second included angle β. In this way, by providing the angle detection apparatus, the included angle between the first light <NUM> and the detection surface <NUM> and the included angle between the second light <NUM> and the detection surface <NUM> can be detected, thus facilitating the determination of whether the second included angle β is less than the first included angle α. Moreover, when the included angle between the first light <NUM> and the detection surface <NUM> and the included angle between the second light <NUM> and the detection surface <NUM> are not within an appropriate range, this can be accurately detected by the angle detection apparatus, thus facilitating timely adjustment of the first light source <NUM> and the second light source <NUM>.

Further, the angle detection apparatus can be communicatively connected to the control assembly, and the angle detection apparatus can transmit the detected angle information to the control assembly, and according to the received angle information, the control assembly determines whether the angle range of the included angle between the first light <NUM> and the detection surface <NUM> is within the angle range of the first included angle α, and determines whether the angle range of the included angle between the second light <NUM> and the detection surface <NUM> is within the angle range of the second included angle β. It should be noted that the specific construction of the angle detection apparatus is not specifically limited, as long as the angle detection apparatus can detect the included angle between the first light <NUM> and the detection surface <NUM> and the included angle between the second light <NUM> and the detection surface <NUM>.

In some embodiments, the battery cell appearance defect detection apparatus <NUM> may further include: an alarm apparatus, wherein the alarm apparatus is communicatively connected to the control assembly, and the alarm apparatus may be an audible alarm and/or a light alarm, and the present application is illustrated taking the alarm apparatus being an audible alarm as an example. When the angle detection apparatus detects that the included angle between the first light <NUM> and the detection surface <NUM> and the included angle between the second light <NUM> and the detection surface <NUM> are not within the appropriate range, the control assembly controls the alarm apparatus to issue an alarm to alert the operator that the included angle between the first light <NUM> and the detection surface <NUM> and the included angle between the second light <NUM> and the detection surface <NUM> are not within the appropriate range.

According to some embodiments of the present application, the present application also provides a detection device comprising the battery cell appearance defect detection apparatus <NUM> of the above embodiments. Here, the detection device may have stations for detecting other parameters of the battery cell <NUM>, and the battery cell appearance defect detection apparatus <NUM> is located at one of the stations in the detection device.

In some embodiments, there are a plurality of battery cell appearance defect detection apparatuses <NUM>, the plurality of battery cell appearance defect detection apparatuses <NUM> being used for correspondingly detecting a plurality of detection surfaces <NUM> of the battery cell <NUM>. In particular, when detecting the appearance defects of the battery cell <NUM>, each detection surface <NUM> corresponds at least to one battery cell appearance defect detection apparatus <NUM>, and the battery cell appearance defect detection apparatus <NUM> is used for detecting the corresponding detection surface <NUM>. With such settings, it is possible to achieve the effect of detection of a plurality of detection surfaces <NUM> by a plurality of battery cell appearance defect detection apparatuses <NUM>, which can improve the efficiency of detecting appearance defects of the battery cell <NUM>.

The battery cell appearance defect detection apparatus <NUM> of the present application is described below with reference to <FIG>.

As shown in <FIG>, when the upper surface of the battery cell <NUM> needs to be detected, the upper surface of the battery cell <NUM> is the detection surface <NUM>, and the battery cell appearance defect detection apparatus <NUM> is disposed above the battery cell <NUM>. The first image collector <NUM>, the first light source <NUM>, the second image collector <NUM>, and the second light source <NUM> are turned on for operation, wherein the first light source <NUM> emits first light <NUM> toward the detection surface <NUM> of the battery cell <NUM>, and the first light <NUM> forms a first included angle α with the detection surface <NUM>, and the first image collector <NUM> performs image scanning to collect the first image of the position of the battery cell <NUM> irradiated by the first light <NUM>. The first image collector <NUM> transmits the collected first image to the control assembly, and a pre-tuned AI algorithm in the control assembly detects whether there are foreign matter particles and air bubbles on the inner side of the film of the film-clad battery cell <NUM>, and the AI algorithm distinguishes between the air bubbles on the inner side of the film and the foreign matter on the inner side of the film based on different forms.

In addition, the second light source <NUM> emits second light <NUM> toward the detection surface <NUM> of the battery cell <NUM>, and the second light <NUM> forms a second included angle β with the detection surface <NUM>. At the end of the scanning, the first image collector <NUM> transmits the collected second image to the control assembly, and then the pre-tuned AI algorithm in the control assembly detects whether there are pits on the surface of the battery cell <NUM>.

It should be noted that in case of no conflicts, the embodiments in the present application and features in the embodiments may be combined with each other.

In the description of this specification, descriptions referring to terms "one embodiment", "some embodiments", "exemplary embodiments", "examples", "specific example", or "some examples" mean that specific features, structures, materials or characteristics described in connection with this embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms does not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

Claim 1:
A film-clad battery cell appearance defect detection apparatus (<NUM>), comprising
a first detection assembly (<NUM>) comprising a first image collector (<NUM>) and a first light source (<NUM>), wherein the first light source (<NUM>) is used to emit first light (<NUM>) toward a detection surface (<NUM>) of a battery cell (<NUM>), the first light (<NUM>) being adapted to pass through an outer film of the battery cell (<NUM>), and the first light (<NUM>) forming a first included angle (α) with the detection surface (<NUM>), and the first image collector (<NUM>) is used to collect a first image of the position on the battery cell (<NUM>) irradiated by the first light (<NUM>);
a second detection assembly (<NUM>) comprising a second image collector (<NUM>) and a second light source (<NUM>), wherein the second light source (<NUM>) is used to emit second light (<NUM>) toward the detection surface (<NUM>), the second light (<NUM>) forming a second included angle (β) with the detection surface (<NUM>), and the second image collector (<NUM>) is used to collect a second image of the position on the battery cell (<NUM>) irradiated by the second light (<NUM>), with the second included angle (β) being less than the first included angle (α); and
a control assembly connected respectively with the first image collector (<NUM>) and the second image collector (<NUM>), the control assembly being constructed to detect appearance defects of the battery cell (<NUM>) according to the first image and the second image, wherein the appearance defects comprise defects between the outer film and a shell of the battery cell (<NUM>) and defects on the outer film;
wherein the first light (<NUM>) and the second light (<NUM>) are both infrared scanning light; and wherein the wavelength of the first light (<NUM>) and the wavelength of the second light (<NUM>) are both wavelengths which satisfy the relational expression: <NUM> ≤ λ ≤ <NUM>.