Method for detecting contact state of grid line of battery piece

Abstract

The invention discloses a method for detecting the contact state of a grid line of a battery piece. The method comprises the following steps: electrically connecting a positive grid line and a negative grid line through a conductive object; while a light source is utilized to irradiate the surface of a battery piece body, the surface of the battery piece body is shot to obtain a shot picture, the battery piece is not provided with a main grid, the battery piece comprises the battery piece body and a plurality of metal grid lines, and the metal grid lines are located on the surface of the battery piece body. The plurality of metal grid lines comprise a plurality of positive grid lines and a plurality of negative grid lines; and at least determining the contact state of the metal grid lines and the battery piece body according to the gray value of the shot picture. The technical problem that the ohmic contact condition of the metal grid line is difficult to evaluate due to the fact that the 0BB battery piece has no main grid in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a method for detecting the contact state of a grid line of a battery cell. Background Art

[0002] Due to the characteristics of 0BB (Zero Bus Bar) cells without a main grid, it is difficult to test the electrical performance through the contact method, and it is difficult to evaluate whether the metallization process enables the metal grid line to form a good ohmic contact.

[0003] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiment of the present invention provides a method for detecting the contact status of a cell grid line, so as to at least solve the technical problem in the related art that the ohmic contact status of the metal grid line is difficult to evaluate due to the lack of a main grid in the 0BB cell.

[0005] According to one aspect of an embodiment of the present invention, there is provided a method for detecting the contact state of a grid line of a battery cell, wherein the battery cell has no main grid, and the battery cell comprises a battery cell body and a plurality of metal grid lines, wherein the metal grid lines are located on a surface of the battery cell body, and the plurality of metal grid lines comprise a plurality of positive grid lines and a plurality of negative grid lines, and the method comprises: electrically connecting the positive grid lines and the negative grid lines via a conductive object; photographing the surface of the battery cell body while irradiating the surface of the battery cell body with a light source to obtain a photographed image; and determining at least the contact state of the metal grid lines with the battery cell body according to the grayscale value of the photographed image.

[0006] Optionally, photographing the surface of the cell body while irradiating the surface of the cell body with a light source includes: photographing the surface of the cell body with a photoluminescent device.

[0007] Optionally, a photoluminescence device is used to photograph the surface of the cell body, including: using a PL (Photoluminescence) camera with a planar light source to photograph the entire surface of the cell body.

[0008] Optionally, based on the grayscale value of the captured image, at least the contact state between the metal grid line and the battery cell body is determined, including: when there is a luminous area in the captured image, determining that the metal grid line corresponding to the luminous area is in poor contact, and the luminous area is an area characterized by a grayscale value greater than a threshold grayscale; when there is no luminous area in the captured image, determining that all the metal grid lines are in good contact.

[0009] Optionally, the metal grid line is a fine grid, a plurality of the metal grid lines are arranged along a first direction, the metal grid lines extend along a second direction, the first direction intersects with the second direction, and a conductive object is used to electrically connect the positive grid line and the negative grid line through the conductive object, including: contacting the conductive object with a grid line surface of the battery cell body so that the positive grid line is electrically connected to the negative grid line, and the grid line surface is a surface that represents contact with the metal grid line.

[0010] Optionally, bringing the conductive object into contact with the gridline surface of the battery cell body includes: bringing the conductive object into contact with the gridline surface so that an angle between a surface of the conductive object and the gridline surface is 10°-90°.

[0011] Optionally, the positive grid lines and the negative grid lines are located on the same surface of the battery cell body, and the surface of the battery cell body is photographed, including: when the conductive object is opaque and the metal grid lines are completely covered by the conductive object, photographing the grid line-free surface of the battery cell body, the grid line-free surface being a surface that is not in contact with the metal grid lines.

[0012] Optionally, the positive grid line and the negative grid line are located on different surfaces of the battery cell body, the conductive object includes a first sub-conductive object and a second sub-conductive object, and the conductive object is brought into contact with the grid line surface of the battery cell body, comprising: bringing the first sub-conductive object into contact with the first surface of the battery cell body, and bringing the second sub-conductive object into contact with the second surface of the battery cell body, the first surface being a surface representing contact with the positive grid line, and the second surface being a surface representing contact with the negative grid line; and electrically connecting the first sub-conductive object and the second sub-conductive object via a wire.

[0013] Optionally, after the conductive object is brought into contact with the grid line surface of the battery cell body and before the surface of the battery cell body is photographed, the method for detecting the contact state of the battery cell grid lines further includes: applying pressure to the surface of the conductive object and / or the surface of the battery cell body.

[0014] Optionally, applying pressure to the surface of the conductive object and / or the surface of the battery cell body includes: applying pressure to the surface of the conductive object and / or the surface of the battery cell body by vacuum adsorption.

[0015] In an embodiment of the present invention, the cell has no main grid, and the cell includes a cell body and a plurality of metal grid lines located on the surface of the cell body, the plurality of metal grid lines include a plurality of positive grid lines and a plurality of negative grid lines, the positive grid lines and the negative grid lines are first electrically connected through a conductive object, and then when the surface of the cell body is irradiated with a light source, the surface of the cell body is photographed to obtain a photographed picture, and finally, according to the grayscale value of the photographed picture, at least the contact state between the metal grid lines and the cell body is determined. The present application uses a conductive object to electrically connect the positive grid lines and the negative grid lines to ensure that a closed loop is formed between the positive grid lines and the negative grid lines, and photographs the surface of the cell body when the light source is irradiated to obtain a photographed picture, and analyzes the contact state between the metal grid lines and the cell body according to the grayscale value of the photographed picture, thereby achieving the technical effect of rapid analysis of poor contact of the grid lines of the OBB cell, ensuring high efficiency and reliability of detection, and thus solving the technical problem in the related art that the ohmic contact of the metal grid lines is difficult to evaluate due to the lack of main grids in the OBB cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 It is a schematic flow chart of a method for detecting the contact state of a grid line of a battery cell provided in accordance with an embodiment of the present invention;

[0018] Figure 2 is a schematic diagram of a conductive object and a back-junction solar cell grid line pressed together according to an embodiment of the present invention;

[0019] Figure 3 It is a schematic diagram of another conductive object pressed together with a back-junction solar cell grid line according to an embodiment of the present invention.

[0020] The above drawings include the following reference numerals:

[0021] 10. Back-junction battery cell; 11. Metal grid line; 111. Positive grid line; 112. Negative grid line; 12. Conductive object. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] As introduced in the background technology, in the related art, it is difficult to evaluate the ohmic contact of the metal grid line because the 0BB cell has no main grid. In view of the above defects, a method for detecting the contact state of the grid line of a cell is provided in an embodiment of the present invention.

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] According to an embodiment of the present invention, a method embodiment of a method for detecting the contact status of a battery cell grid line is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0027] Figure 1 The present invention is a flow chart of a method for detecting the contact state of a cell grid line according to an embodiment of the present invention. The cell has no main grid, the cell comprises a cell body and a plurality of metal grid lines, the metal grid lines are located on the surface of the cell body, the plurality of metal grid lines comprise a plurality of positive grid lines and a plurality of negative grid lines, such as Figure 1 As shown, the method comprises the following steps:

[0028] Step S201, electrically connecting the positive electrode grid wire and the negative electrode grid wire through a conductive object;

[0029] Step S202, while irradiating the surface of the battery cell body with a light source, photographing the surface of the battery cell body to obtain a photographed picture;

[0030] Specifically, since the battery cell body is made of semiconductor material, when the surface of the battery cell body is irradiated by the light source, the battery cell body will generate free carriers.

[0031] Step S203, determining at least the contact state between the metal grid line and the battery cell body according to the grayscale value of the captured image.

[0032] As can be seen from the above, in an embodiment of the present invention, the cell has no main grid, and the cell includes a cell body and a plurality of metal grid lines located on the surface of the cell body, the plurality of metal grid lines include a plurality of positive grid lines and a plurality of negative grid lines, the positive grid lines and the negative grid lines are first electrically connected through a conductive object, and then when the surface of the cell body is irradiated with a light source, the surface of the cell body is photographed to obtain a photographed picture, and finally, according to the grayscale value of the photographed picture, at least the contact state between the metal grid lines and the cell body is determined. The present application uses a conductive object to electrically connect the positive grid lines and the negative grid lines to ensure that a closed loop is formed between the positive grid lines and the negative grid lines, and photographs the surface of the cell body when the light source is irradiated to obtain a photographed picture, and analyzes the contact state between the metal grid lines and the cell body according to the grayscale value of the photographed picture, thereby achieving the technical effect of rapid analysis of poor contact of the OBB cell grid lines, ensuring high efficiency and reliability of detection, and thus solving the technical problem in the related art that the ohmic contact of the metal grid lines is difficult to evaluate due to the lack of a main grid in the OBB cell.

[0033] The technical solution provided by the embodiment of the present invention solves the technical problem in the related art that the ohmic contact of the metal grid line is difficult to evaluate due to the lack of a main grid in the 0BB battery cell.

[0034] Specifically, since the battery cell body is made of semiconductor material, when the surface of the battery cell body is irradiated by the light source, the battery cell body will generate free carriers, that is, the electrons absorb light energy and are excited to a high energy state to form free carriers, but this high energy state is in dynamic equilibrium and can only be maintained for a very short time; for areas where the metal grid lines are poorly contacted, these high energy electrons (that is, free carriers) need to release energy to return to a low energy state in order to maintain dynamic equilibrium, and the released energy is released in the form of waves (that is, it will emit light); and for areas where the metal grid lines are well contacted, the positive grid lines are electrically connected to the negative grid lines, and the electrons and holes in this area directly leak and recombine, so that the electrons in the high energy state are collected, so it is no longer necessary to release energy to return to a low energy state in order to maintain dynamic equilibrium, so very little light is emitted.

[0035] Specifically, poor contact of the metal grid line means that the contact between the metal grid line and the battery cell body is poor, or the metal grid line is broken.

[0036] Specifically, the conductive material of the above-mentioned conductive object may include: metal, conductive silicone, conductive plastic, conductive sponge, conductive film and other any good conductor materials, and its shape may include: filament, strip or whole surface, and the present application does not impose any specific restrictions on this.

[0037] According to the above embodiment of the present invention, while irradiating the surface of the cell body with a light source, photographing the surface of the cell body includes: photographing the surface of the cell body with a photoluminescent device. In this embodiment, the photoluminescent device has a light source and a camera, and photographing the surface of the cell body with the photoluminescent device ensures that the photographed picture is relatively accurate, thereby further ensuring that the subsequent detection of the metal grid line is relatively accurate.

[0038] In the above embodiment of the present invention, the surface of the cell body is photographed using a photoluminescent device, including: photographing the entire surface of the cell body using a PL camera with a planar array light source. In this embodiment, the entire surface of the cell body is photographed using a PL camera with a planar array light source, ensuring that the entire cell can be evenly illuminated, thereby obtaining a comprehensive image of the metal grid lines and the cell, thereby further ensuring that the subsequent detection of the metal grid lines is more accurate.

[0039] According to the above embodiment of the present invention, at least the contact state between the metal grid line and the cell body is determined based on the grayscale value of the captured image, including: when there is a luminous area in the captured image, determining that the metal grid line corresponding to the luminous area is in poor contact, and the luminous area is an area characterized by a grayscale value greater than a threshold grayscale; when there is no luminous area in the captured image, determining that all metal grid lines are in good contact. In this embodiment, when there is a luminous area in the captured image, it is determined that the metal grid line corresponding to the luminous area is in poor contact, and when there is no luminous area in the captured image, it is determined that all metal grid lines are in good contact, which further ensures that the detection of the metal grid line is relatively accurate.

[0040] In this embodiment, when the conductive plate is completely connected to the grid line of the battery cell, in the analysis of the results of taking the PL picture, if there is partial light emission in the PL image, that part of the battery cell has not achieved good ohmic contact, and it is judged as poor grid line contact; if the entire surface is dark (the grayscale value of the entire surface is less than the threshold grayscale), it can be considered that the P and N regions of the battery cell have achieved good ohmic contact with the metal grid line, and it is judged as good. The contact condition of the metal grid line can be determined by taking pictures, and especially the detection of the light-emitting area can effectively find out the poor contact and discover the problem of poor metal grid line contact early.

[0041] According to the above embodiment of the present invention, the metal grid line is a thin grid, a plurality of metal grid lines are arranged along a first direction, the metal grid lines extend along a second direction, the first direction intersects with the second direction, and a conductive object is used to electrically connect the positive grid line and the negative grid line through the conductive object, including: contacting the conductive object with the grid line surface of the battery cell body so that the positive grid line and the negative grid line are electrically connected, and the grid line surface is a surface that characterizes contact with the metal grid line. In this embodiment, contacting the conductive object with the grid line surface of the battery cell body further ensures that the positive grid line and the negative grid line can be better electrically connected, and ensures that the current can be effectively transmitted, so as to prepare for the subsequent detection of the contact state of the metal grid line.

[0042] Specifically, the conductive object is pressed onto the grid line surface of the battery cell body.

[0043] In the above embodiment of the present invention, the conductive object is brought into contact with the grid line surface of the battery cell body, including: bringing the conductive object into contact with the grid line surface so that the angle between the surface of the conductive object and the grid line surface is 10°-90°. In this embodiment, the angle between the conductive object and the metal grid line is 10°-90° to ensure a good contact area between the conductive object and the grid line surface, reduce contact resistance, and improve conduction efficiency. In addition, a proper angle can also reduce friction and wear between contact surfaces and extend the life of the conductive object.

[0044] It should be noted that the angle between the conductive material and the metal grid line is usually 10°-90°. Since the conductive object can be in the form of strips, wires or a whole surface, conductive objects of different shapes can be electrically connected to the grid line surface of the battery cell body. The best placement is vertical, that is, 90° (as long as all metal grid lines can be connected, the angle has little effect on the result).

[0045] According to the above embodiment of the present invention, the positive grid lines and the negative grid lines are located on the same surface of the cell body, and the surface of the cell body is photographed, including: when the conductive object is opaque and the metal grid lines are completely covered by the conductive object, the grid line-free surface of the cell body is photographed, and the grid line-free surface is a surface that is characterized as not in contact with the metal grid lines. In this embodiment, when the conductive object is opaque and the metal grid lines are completely covered by the conductive object (that is, when the entire non-transparent conductive object is used), the grid line-free surface of the cell body is photographed, ensuring that the cell body can receive light to generate free carriers, thereby preparing for the subsequent detection of the metal grid lines.

[0046] Specifically, the positive electrode grid lines and the negative electrode grid lines of the back-junction solar cell are located on the same surface (back side) of the solar cell body.

[0047] It should be noted that when using non-entirely conductive objects such as conductive wires, or entirely transparent conductive objects (such as transparent conductive film ITO (Indium Tin Oxide, indium tin oxide), etc.), when the positive grid lines and the negative grid lines are connected, the shooting direction can be the surface without grid lines or the surface with grid lines; when using an entirely non-transparent conductive object, the shooting direction is the surface without grid lines, and the surface with grid lines may interfere with the propagation and reflection of light, affecting the accuracy of taking pictures.

[0048] Figure 2 FIG. 1 is a schematic diagram of a conductive object and a back-junction solar cell grid line pressed together according to an embodiment of the present invention. Figure 2 As shown, the back-junction solar cell 10 includes a plurality of metal grid lines 11, and the plurality of metal grid lines 11 include a plurality of positive grid lines 111 and a plurality of negative grid lines 112. The conductive object 12 is a conductive wire or a strip-shaped conductive plate. The conductive object 12 is intersected with the extension direction (i.e., the first direction) of the metal grid lines 11. When placed vertically, the crosstalk and stray coupling effects in the circuit can be minimized to the greatest extent, and the interference of electromagnetic radiation to the surrounding environment and other electronic equipment can be reduced.

[0049] Figure 3 FIG. 1 is a schematic diagram of another conductive object and a back-junction solar cell grid line pressed together according to an embodiment of the present invention. Figure 3 As shown, the conductive object 12 is a whole-surface conductive plate, and the grid line surface is in contact with the conductive object 12, ensuring that the contact area between the conductive object 12 and the back-junction battery cell 10 is maximized, thereby improving the electron conduction efficiency and reducing the electron conduction resistance caused by the gap between the conductive object 12 and the back-junction battery cell 10.

[0050] Specifically, Figure 2 As shown, the positive electrode grid lines 111 and the negative electrode grid lines 112 of the back-junction solar cell 10 are arranged crosswise.

[0051] In the above embodiment of the present invention, the positive grid line and the negative grid line are located on different surfaces of the battery cell body, the conductive object includes a first sub-conductive object and a second sub-conductive object, and the conductive object is brought into contact with the grid line surface of the battery cell body, including: bringing the first sub-conductive object into contact with the first surface of the battery cell body, and bringing the second sub-conductive object into contact with the second surface of the battery cell body, the first surface being a surface characterized by contact with the positive grid line, and the second surface being a surface characterized by contact with the negative grid line; and the first sub-conductive object and the second sub-conductive object are electrically connected through a wire. In this embodiment, the first sub-conductive object is brought into contact with the positive grid line surface (i.e., the first surface) of the battery cell body, so that the conductive connection of the positive grid line can be achieved, and the second sub-conductive object is brought into contact with the negative grid line surface (i.e., the second surface) of the battery cell body, so that the conductive connection of the negative grid line can be achieved, and then the first sub-conductive object and the second sub-conductive object are electrically connected through a wire, so that the conductive connection of the positive grid line and the negative grid line can be achieved, thereby achieving the transmission of current, and the conductive properties of the conductive object and the wire can be effectively utilized, so as to facilitate the detection of the contact of the metal grid line.

[0052] Specifically, for a battery cell in which the positive electrode grid lines and the negative electrode grid lines are located on different surfaces of the battery cell body, the conductive object cannot be a conductive object that is entirely non-transparent.

[0053] According to the above embodiment of the present invention, after the conductive object is brought into contact with the grid line surface of the cell body and before the surface of the cell body is photographed, the method for detecting the contact state of the cell grid line further includes: applying pressure to the surface of the conductive object and / or the surface of the cell body. In this embodiment, applying a certain pressure to the surface of the conductive object or the cell body can ensure that the conductive object is in full contact with the cell body, further ensuring that the positive grid line and the negative grid line are well electrically connected, thereby further ensuring that the current can be well transmitted, and further ensuring that the subsequent detection of the metal grid line is more accurate.

[0054] Specifically, the battery cell can be placed on a carrier, and pressure can be applied to the conductive object and the surface of the battery cell body by pressing the conductive object downward.

[0055] According to the above embodiment of the present invention, applying pressure to the surface of the conductive object and / or the surface of the battery cell body includes: applying pressure to the surface of the conductive object and / or the surface of the battery cell body by vacuum adsorption. In this embodiment, pressure can be applied to the surface of the conductive object and the battery cell body by vacuum adsorption, which can ensure that the pressure applied to the conductive object and the battery cell body is uniform and stable. In a vacuum environment, the interference of air or other gases can be effectively eliminated, ensuring the firmness and stability of adsorption, avoiding the generation of bubbles when applying pressure, and better protecting the surface of the conductive object and the battery cell body.

[0056] Through the technical solution provided by the above-mentioned embodiment of the present invention, a conductive object is pressed onto the grid line surface of a battery cell without a main grid, so that it can short-circuit all metal grid lines, and then a PL camera with a planar array light source is used to photograph the battery cell. The resulting luminous area is the area where the metal grid line has poor contact with the battery cell.

[0057] Specifically, the method for detecting the contact status of the grid line of the battery cell of the present application can be used not only for 0BB battery cells, but also for the grid line defect detection of back junction batteries such as IBC (Interdigitated Back Contact, cross back contact battery technology), ABC (All Back Contact, all back contact battery technology), HPBC (High Performance Back Contact, high performance back contact battery technology), and HBC (Heterojunction Back Contact, heterojunction back contact battery technology) of MBB (Multi-Busbar, multi-busbar battery technology).

[0058] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0059] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting the contact state of a grid line of a battery cell, characterized in that: The battery cell has no main grid, and the battery cell includes a battery cell body and a plurality of metal grid lines, wherein the metal grid lines are located on the surface of the battery cell body. The plurality of metal grid lines include a plurality of positive grid lines and a plurality of negative grid lines, and the method includes: The positive electrode grid wire and the negative electrode grid wire are electrically connected through a conductive object; When the surface of the battery cell body is illuminated by a light source, the surface of the battery cell body is photographed to obtain a photographed picture; At least the contact state between the metal grid line and the battery cell body is determined according to the grayscale value of the captured image.

2. The method for detecting the contact state of a cell grid line according to claim 1, characterized in that: When the surface of the battery cell body is illuminated by a light source, the surface of the battery cell body is photographed, including: The surface of the battery cell body is photographed using a photoluminescence device.

3. The method for detecting the contact state of a cell grid line according to claim 2, characterized in that: Using a photoluminescent device to photograph the surface of the cell body includes: The entire surface of the battery cell body is photographed using a PL camera with a planar array light source.

4. The method for detecting the contact state of a cell grid line according to claim 3, characterized in that: According to the grayscale value of the captured image, at least determining the contact state between the metal grid line and the battery cell body includes: In the case where there is a luminous area in the captured image, determining that the metal grid line corresponding to the luminous area has poor contact, the luminous area being an area characterized by a grayscale value greater than a threshold grayscale; In the case where the light-emitting area does not exist in the captured image, it is determined that all the metal grid lines are in good contact.

5. The method for detecting the contact state of a cell grid line according to claim 1, characterized in that: The metal grid lines are thin grids, a plurality of the metal grid lines are arranged along a first direction, the metal grid lines extend along a second direction, the first direction intersects with the second direction, and the positive grid lines and the negative grid lines are electrically connected through a conductive object, including: The conductive object is brought into contact with the gridline surface of the battery cell body so that the positive gridline is electrically connected to the negative gridline, and the gridline surface is characterized by the surface in contact with the metal gridline.

6. The method for detecting the contact state of the grid line of a battery cell according to claim 5, characterized in that: Bringing the conductive object into contact with the grid line surface of the battery cell body includes: The conductive object is brought into contact with the grid line surface so that the angle between the surface of the conductive object and the grid line surface is 10°-90°.

7. The method for detecting the contact state of a cell grid line according to claim 5, characterized in that: The positive electrode grid lines and the negative electrode grid lines are located on the same surface of the battery cell body, and the surface of the battery cell body is photographed, including: In the case where the conductive object is opaque and the metal grid lines are completely covered by the conductive object, the grid line-free surface of the battery cell body is photographed, where the grid line-free surface is characterized as a surface that is not in contact with the metal grid lines.

8. The method for detecting the contact state of a cell grid line according to claim 5, characterized in that: The positive electrode grid line and the negative electrode grid line are located on different surfaces of the battery cell body, the conductive object includes a first sub-conductive object and a second sub-conductive object, and the conductive object is brought into contact with the grid line surface of the battery cell body, including: The first sub-conductive object is brought into contact with the first surface of the battery cell body, and the second sub-conductive object is brought into contact with the second surface of the battery cell body, wherein the first surface is a surface in contact with the positive electrode grid line, and the second surface is a surface in contact with the negative electrode grid line; The first sub-conductive object is electrically connected to the second sub-conductive object through a wire.

9. The method for detecting the contact state of a cell grid line according to claim 5, characterized in that: After the conductive object is brought into contact with the grid line surface of the battery cell body and before the surface of the battery cell body is photographed, the method further includes: Applying pressure to the surface of the conductive object and / or the surface of the battery cell body.

10. The method for detecting the contact state of the grid line of a battery cell according to claim 9, characterized in that: Applying pressure to the surface of the conductive object and / or the surface of the battery cell body comprises: Pressure is applied to the surface of the conductive object and / or the surface of the battery cell body through vacuum adsorption.

Images