Roller, coating apparatus, and coating method

Abstract

Embodiments of the present application provide a roller, a film coating device and a film coating method. The roller comprises a shaft core part and a rolling part sleeved on the shaft core part; the rolling part comprises at least three subparts arranged along the circumference of the shaft core part, the outer circumferential surface of the at least three subparts comprises an arc convex surface, an arc concave surface and a cylindrical surface, and the shape of the outer circumferential surface of adjacent two subparts is different. Wherein, along the axial direction of the shaft core part, the middle part of the arc convex surface protrudes away from the shaft core part relative to the two ends of the arc convex surface, and the middle part of the arc concave surface is recessed towards the shaft core part relative to the two ends of the arc concave surface. The rolling part of the roller in the embodiments of the present application comprises a plurality of subparts with different outer circumferential surface shapes, which can be compatible with the requirements of different flatness of the plurality of battery cells. The arc convex surface, the arc concave surface and the cylindrical surface are used to flatten the concave / convex area of the protective film and the battery cell, to discharge the air between the protective film and the battery cell, and to improve the film coating reliability and yield.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, and in particular to a roller, a film coating device and a film coating method. BACKGROUND

[0002] With the rapid development of economy and technology, power batteries are increasingly widely used. The surface of the power battery cell usually needs to be coated with a protective film. The protective film can ensure the insulation between the power batteries, and can also protect the cell from the external environment, reducing cell damage and short circuit.

[0003] The power battery film coating has two film coating methods: manual film coating and automatic film coating by a film coating device. The quality of manual film coating is poor, which affects subsequent assembly and makes it difficult to ensure the performance of the cell. The automatic film coating by the film coating device uses upper and lower rollers to press the protective film, so that the protective film is tightly attached to the surface of the cell, and the upper and lower rollers are used to coat the two large faces of the cell. However, the automatic film coating by the film coating device is difficult to completely expel the air between the protective film and the cell, and the yield is low. SUMMARY

[0004] Embodiments of the present application provide a roller, a film coating device and a film coating method to expel the air between the protective film and the cell, and improve the film coating yield.

[0005] In a first aspect, embodiments of the present application provide a roller for coating a plurality of cells, the roller comprising: a shaft core portion, and a roller pressing portion sleeved on the shaft core portion;

[0006] The roller pressing portion comprises at least three sub-portions arranged along the circumference of the shaft core portion, the shape of the outer circumferential surface of the at least three sub-portions comprises an arc convex surface, an arc concave surface and a cylindrical surface, and the shape of the outer circumferential surface of adjacent two sub-portions is different;

[0007] Wherein, along the axial direction of the shaft core portion, the middle part of the arc convex surface protrudes away from the shaft core portion relative to the two ends of the arc convex surface, and the middle part of the arc concave surface is recessed towards the shaft core portion relative to the two ends of the arc concave surface.

[0008] In some possible implementations, the two adjacent sub-portions are circularly arc transitioned at one end adjacent to each other.

[0009] In some possible implementations, the material of the roller pressing portion comprises a silica gel material.

[0010] In some possible implementations, along the axial direction of the shaft core portion, the two opposite ends of the roller pressing portion are circular rings or elliptical rings.

[0011] In some possible implementations, the number of sub-portions is an integer multiple of 3.

[0012] The shape of the outer circumferential surface of each of the sub-sections is cyclically arranged along the circumferential direction of the shaft core, and is in sequence an arc convex surface, an arc concave surface and a cylindrical surface, or in sequence an arc convex surface, a cylindrical surface and an arc concave surface.

[0013] In some possible embodiments, the roller pressing part is divided into a plurality of sub-sections.

[0014] In some possible embodiments, the chord length corresponding to the central angle of each of the sub-sections is the minimum value of the average of the width of the convex region and the average of the width of the concave region of the film surface of the plurality of battery cells.

[0015] In some possible embodiments, the depth of the lowest point of the arc concave surface is the maximum value of the convex height of the convex region of the film surface of the plurality of battery cells.

[0016] In some possible embodiments, the height of the highest point of the arc convex surface is the maximum value of the concave depth of the concave region of the film surface of the plurality of battery cells.

[0017] In some possible embodiments, the compression amount of the roller pressing part is the average of the concave depth of the concave region of the plurality of battery cells, or the average of the convex height of the convex region of the plurality of battery cells.

[0018] In some possible embodiments, the length of each of the sub-sections is the same along the axial direction of the shaft core.

[0019] In a second aspect, an embodiment of the present application provides a film coating device, comprising: a conveying mechanism, a roller wheel as described above, and a driving mechanism;

[0020] The conveying mechanism is configured to convey battery cells, and the driving mechanism is in transmission connection with the roller wheel and configured to drive the roller wheel to rotate.

[0021] In a third aspect, an embodiment of the present application provides a film coating method, comprising:

[0022] detecting the flatness of the film surface of the plurality of battery cells to be coated, and obtaining flatness data of the film surface;

[0023] A roller is formed according to the flatness data, and the roller comprises a shaft core and a roller pressing part sleeved on the shaft core; the roller pressing part comprises at least three sections arranged along the circumference of the shaft core, and the shapes of the outer circumferential surfaces of the at least three sections comprise an arc convex surface, an arc concave surface and a cylindrical surface, and the shapes of the outer circumferential surfaces of two adjacent sections are different; wherein, along the axial direction of the shaft core, the middle part of the arc convex surface protrudes away from the shaft core relative to the two ends of the arc convex surface, and the middle part of the arc concave surface is recessed towards the shaft core relative to the two ends of the arc concave surface.

[0024] The conveying mechanism sends the battery cell to contact with the protective film, and the roller is used to press the protective film on the battery cell.

[0025] In some possible implementation manners, the flatness data comprises a flatness gradient, and the rotating speed of the roller is adjusted in real time according to the flatness gradient when the protective film is pressed on the battery cell.

[0026] In some possible implementation manners, the method further comprises:

[0027] The detection device detects the film wrapping effect of the battery cell, and optimizes the relationship between the rotating speed of the roller and the flatness gradient.

[0028] The roller, the film wrapping device and the film wrapping method in the embodiments of the present application are used for wrapping a plurality of battery cells by using a roller, and the roller comprises a shaft core and a roller pressing part. The roller pressing part comprises at least three sections arranged along the circumference of the shaft core, and the shapes of the outer circumferential surfaces of the at least three sections comprise an arc convex surface, an arc concave surface and a cylindrical surface, and the shapes of the outer circumferential surfaces of two adjacent sections are different. Wherein, along the axial direction of the shaft core, the middle part of the arc convex surface protrudes away from the shaft core relative to the two ends of the arc convex surface, and the middle part of the arc concave surface is recessed towards the shaft core relative to the two ends of the arc concave surface. The roller pressing part comprises a plurality of sections with different outer circumferential shapes, which can meet the requirements of different flatness of a plurality of battery cells. The arc convex surface, the arc concave surface and the cylindrical surface are used to press the recessed area / protruding area of the protective film and the battery cell, to discharge the air between the protective film and the battery cell, and to improve the film wrapping reliability and the film wrapping yield. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings incorporated into the specification and forming a part thereof, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0030] Figure 1 It is a schematic diagram of a roller in the related art;

[0031] Figure 2 It is a schematic diagram of a battery cell film wrapping provided by the present application;

[0032] Figure 3 A schematic view of a coated surface of a battery cell is provided for the present application;

[0033] Figure 4 A schematic view of a first section in one direction is provided for the present application;

[0034] Figure 5 A schematic view of the first section in another direction is provided for the present application;

[0035] Figure 6 A schematic view of the first section in yet another direction is provided for the present application;

[0036] Figure 7 A perspective view of the first section is provided for the present application;

[0037] Figure 8 A schematic view of a second section in one direction is provided for the present application;

[0038] Figure 9 A schematic view of the second section in another direction is provided for the present application;

[0039] Figure 10 A schematic view of the second section in yet another direction is provided for the present application;

[0040] Figure 11 A perspective view of the second section is provided for the present application;

[0041] Figure 12 A schematic view of a third section in one direction is provided for the present application;

[0042] Figure 13 A schematic view of the third section in another direction is provided for the present application;

[0043] Figure 14 A schematic view of the third section in yet another direction is provided for the present application;

[0044] Figure 15 A perspective view of the third section is provided for the present application;

[0045] Figure 16 A schematic view of a chord of the sections is provided for the present application;

[0046] Figure 17 A flow chart of a coating method is provided for the present application;

[0047] Figure 18 A process chart of a coating method is provided for the present application;

[0048] Figure 19 A flow chart of a coating method is provided for the present application.

[0049] Reference Signs List:

[0050] 10 - cell

[0051] 11 - wrapping surface

[0052] 12 - recessed area

[0053] 13 - raised area

[0054] 20 - roller

[0055] 21 - shaft core

[0056] 22 - section

[0057] 23 - arc convex surface

[0058] 24 - arc concave surface

[0059] 25 - cylindrical surface

[0060] 30 - protective film DETAILED DESCRIPTION

[0061] The exemplary embodiments will be described in detail with reference to the drawings. In the following description, unless otherwise indicated, like numbers in the different drawings indicate like or similar elements. The following exemplary embodiments are described in enough detail to enable those skilled in the art to practice the inventive subject matter. The embodiments described herein are not meant to be limiting. Other embodiments can be utilized, and other changes can be made, without departing from the scope of the present disclosure.

[0062] In the related art, it is difficult to completely expel the air between the protective film and the cell, and the wrapping yield is low. The reason is that Figure 1 and Figure 2 When wrapping the cell 10 with the protective film 30, a cylindrical roller 20 is often used. The roller 20 rolls over the protective film 30, so that the protective film 30 is tightly attached to the wrapping surface 11 of the cell 10.

[0063] However, referring to Figure 1 and Figure 3 , the wrapping surface 11 of the cell 10 often has unevenness, Figure 2 The cylindrical roller 20 shown in the drawing cannot flatten the recessed area 12 and the raised area 13, so that it is difficult to expel the air between the protective film 30 and the cell 10, resulting in air bubbles or wrinkles, and the wrapping yield is low.

[0064] The embodiment of the present application provides a roller, the roller comprises at least three parts, the shape of the outer periphery of the parts comprises an arc convex surface, an arc concave surface and a cylindrical surface, and the shape of the outer periphery of two adjacent parts is different, so that the roller can meet the requirements of different flatness of multiple battery cells. The arc convex surface, the arc concave surface and the cylindrical surface are used for flattening the concave / convex area of the protective film and the battery cell, discharging air between the protective film and the battery cell, and improving the reliability and yield of film coating.

[0065] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail in the specific embodiments below. The specific embodiments below can be combined with each other, and the same or similar concepts or processes can not be described again in some embodiments. The embodiments of the present application will be described below with reference to the drawings.

[0066] The embodiment of the present application provides a film coating device for coating multiple battery cells. As shown in Figure 1 The battery cell 10 is, for example, a square lithium battery cell, and the coated protective film 30 is a blue film, which is blue and made of polyester materials such as PET and PVC. The battery cell 10 is placed horizontally on the film coating device, that is, the large face of the battery cell 10 is in contact with the film coating device, and the large face of the battery cell 10 refers to the surface with the largest area.

[0067] Referring to Figures 4 to 17 The film coating device comprises a conveying mechanism, a roller 20 and a driving mechanism. The conveying mechanism is used for conveying the battery cell 10, and the driving mechanism is connected with the roller 20 and drives the rotation of the roller 20. Specifically, the conveying mechanism performs battery cell 10 feeding and conveying, battery cell 10 discharging and conveying, and conveying the battery cell 10 to the film coating station.

[0068] The driving mechanism is in transmission connection with the roller 20, and the driving mechanism can drive the rotation of the roller 20 and adjust the rotation speed of the roller 20. The driving mechanism comprises, for example, a servo motor. The roller 20 can rotate and move along the direction close to or away from the film coating surface 11 of the battery cell 10, so as to apply pressure to the large face of the battery cell 10, and press the protective film 30 on the film coating surface 11 of the battery cell 10, thereby realizing the film coating of the battery cell 10.

[0069] The film coating equipment also includes a reeling mechanism, a film stretching mechanism, a film pulling mechanism, and a film cutting mechanism. Among them, the reeling mechanism is used to place the protective film 30 to provide a centrifugal protective film 30 or a common protective film 30. The film stretching mechanism is used to tighten the protective film 30. The film pulling mechanism is used to pull the end of the protective film 30 to the film coating station and adsorb the protective film 30. The film pulling mechanism includes, for example, a manipulator and a negative pressure conveyor belt. The film cutting mechanism is used to cut the protective film 30. For example, the film cutting mechanism includes a cylinder and a cutter connected to the cylinder. The film coating equipment also includes a frame, which provides support. The reeling mechanism, the film stretching mechanism, the film pulling mechanism, the film cutting mechanism, the conveying mechanism, the roller 20 and the driving mechanism can all be arranged on the frame.

[0070] It is understandable that the coating equipment can coat multiple battery cells 10. Among the multiple battery cells 10 to be coated, the flatness of the coating surface 11 of each battery cell 10 is not exactly the same. The coating surface 11 of some battery cells 10 is flat, the coating surface 11 of some battery cells 10 has a recessed area 12, that is, the coating surface 11 of some battery cells 10 is concave, and the coating surface 11 of some battery cells 10 has a raised area 13, that is, the coating surface 11 of some battery cells 10 is convex. The coating surface 11 of some battery cells 10 also has a recessed area 12 and a raised area 13. The flatness of the coating surface 11 of multiple battery cells 10 can be measured by a measuring device to obtain a certain amount of flatness data. The measuring device, for example, includes a 3D camera.

[0071] According to the measured flatness data, the degree of concavity and convexity of the coating surface 11 of the battery cell 10 can be determined. The degree of concavity of the coating surface 11 of the battery cell 10 includes the concavity depth, width and gradient of the concavity area 12. The concavity depth of the concavity area 12 represents the degree of concavity of the concavity area 12, which is the concavity of the concavity area 12 along the thickness direction of the battery cell 10 ( Figure 4 The dimensions of the Z direction are shown as Figure 4 The width of the concave region 12 represents the distribution range of the concave region 12, which is the width of the concave region 12 along the moving direction of the battery cell 10 ( Figure 4 The dimensions of the X direction are shown as Figure 4 The gradient of the concave region 12 represents the slope of the concave region 12 , that is, whether the concave region 12 changes rapidly or slowly.

[0072] The degree of protrusion of the coating surface 11 of the battery cell 10 includes the protrusion height, width and gradient of the protrusion area 13. The protrusion height of the protrusion area 13 represents the degree of protrusion of the protrusion area 13, which is the size of the protrusion area 13 along the thickness direction of the battery cell 10, such as Figure 4 The width of the raised area 13 represents the distribution range of the raised area 13, which is the size of the raised area 13 along the moving direction of the battery cell 10, as shown in FIG. Figure 4The gradient of the raised area 13 represents the slope of the raised area 13, i.e. how fast the raised area 13 changes. The gradient of the raised area 13 and the gradient of the recessed area 12 form the flatness gradient of the film surface 11 of the battery cell 10.

[0073] Referring to Figures 5 to 15 , the roller 20 comprises a shaft core 21 and a roller pressing part sleeved on the shaft core 21; the roller pressing part comprises at least three sub-parts 22 arranged along the circumference of the shaft core 21, the outer circumferential surface of the at least three sub-parts 22 comprises an arc convex surface 23, an arc concave surface 24 and a cylindrical surface 25, and the shape of the outer circumferential surface of adjacent two sub-parts 22 is different; wherein, along the axial direction of the shaft core 21, the middle part of the arc convex surface 23 protrudes away from the shaft core 21 relative to the two ends of the arc convex surface 23, and the middle part of the arc concave surface 24 is recessed towards the shaft core 21 relative to the two ends of the arc concave surface 24.

[0074] Specifically, the shaft core 21 can be columnar, for example, the shaft core 21 is in the shape of a cylinder or an elliptical cylinder. The axial direction of the shaft core 21 is as shown by the M direction in Figure 7 , Figure 11 , Figure 15 , the circumferential direction of the shaft core 21 is as shown by the N direction in Figure 4 , Figure 8 , Figure 12 . The material of the shaft core 21 can be metal, so that the roller 20 has a certain hardness and can provide pressure to the battery cell 10 and the protective film 30.

[0075] The roller pressing part is sleeved outside the shaft core 21, and the roller pressing part is fixed relative to the shaft core 21, for example, the two are in interference fit. Along the axial direction of the shaft core 21, the two ends of the shaft core 21 both protrude outside the roller pressing part, facilitating the shaft core 21 to be connected with a driving mechanism outside the shaft core 21 to drive the shaft core 21 to rotate. The material of the roller pressing part comprises silica gel material, so that the roller pressing part is soft and has a certain deformation amount, thereby ensuring that the roller pressing part can be in close contact with the protective film 30 and air between the protective film 30 and the film surface 11 of the battery cell 10 can be discharged.

[0076] Along the axial direction of the shaft core 21, the roller pressing part comprises at least three sub-parts 22 arranged, i.e. the number of the sub-parts 22 is greater than or equal to three. The shape of the outer circumferential surface of these sub-parts 22 comprises an arc convex surface 23, an arc concave surface 24 and a cylindrical surface 25, and the shape of the outer circumferential surface of adjacent two sub-parts 22 is different, so as to be compatible with the requirements of different flatness of the battery cell 10. In this way, the arc convex surface 23, the arc concave surface 24 and the cylindrical surface 25 can be used to flatten the recessed area 12 / raised area 13 of the protective film 30 and the battery cell 10, discharge air between the protective film 30 and the battery cell 10, and improve the film reliability and film yield.

[0077] Referring to Figures 4 to 7, along the axial direction of the shaft core 21, the middle part of the arc convex surface 23 protrudes away from the shaft core 21 relative to the two ends of the arc convex surface 23. As shown in Figure 7 , along the axial direction of the shaft core 21, the distance between the arc convex surface 23 and the axis (O-O shown) of the shaft core 21 first increases and then decreases. The intersection line of the plane containing the axis of the shaft core 21 and the arc convex surface 23 is an outward convex arc, that is, the intersection line is an outer circular arc.

[0078] , the height of the highest point of the arc convex surface 23 is the maximum value in the concave depths of the concave regions 12 of the film surfaces 11 of the plurality of battery cells 10. In this way, the height of the arc convex surface 23 is greater than or equal to the concave depth of the concave region 12 of the film surface 11 of each battery cell 10, so that the arc convex surface 23 and the concave region 12 are adapted in the radial direction of the shaft core 21.

[0079] Referring to Figures 8 to 11 , along the axial direction of the shaft core 21, the middle part of the arc convex surface 23 protrudes away from the shaft core 21 relative to the two ends of the arc convex surface 23. As shown in Figure 11 , along the axial direction of the shaft core 21, the distance between the arc convex surface 23 and the axis (O-O shown) of the shaft core 21 first increases and then decreases. The intersection line of the plane containing the axis of the shaft core 21 and the arc convex surface 23 is an outward convex arc, that is, the intersection line is an outer circular arc.

[0080] , the depth of the lowest point of the arc concave surface 24 is the maximum value in the convex heights of the convex regions 13 of the film surfaces 11 of the plurality of battery cells 10. In this way, the depth of the arc concave surface 24 is greater than or equal to the convex height of the convex region 13 of the film surface 11 of each battery cell 10, so that the arc concave surface 24 and the convex region 13 are adapted in the radial direction of the shaft core 21.

[0081] Referring to Figures 12 to 15 , the cylindrical surface 25 is a circular cylindrical surface, and along the axial direction of the shaft core 21, the distance between the cylindrical surface 25 and the axis (O-O shown) of the shaft core 21 is equal. The intersection line of the plane containing the axis of the shaft core 21 and the arc concave surface 24 is a straight line.

[0082] In some possible examples, the two ends of the adjacent two parts 22 are circularly arc transitioned to each other. In this way, along the circumferential direction of the shaft core 21, the outer circumferential surfaces of the adjacent two parts 22 are circularly arc connected, which reduces the damage of the roll-pressing part to the protective film 30, and also realizes the cooperation of the entire outer circumferential surface of the roll-pressing part with the film surface 11 of the battery cell 10.

[0083] In some possible examples, the number of the sections 22 is an integer multiple of 3; along the circumference of the shaft core 21, the outer circumferential surface of all the sections 22 is cyclically arranged in the order of the arc convex surface 23, the arc concave surface 24 and the cylindrical surface 25, or in the order of the arc convex surface 23, the cylindrical surface 25 and the arc concave surface 24. For example, the number of the sections 22 is 3, 6, 9, etc., so that the number of the arc convex surfaces 23, the arc concave surfaces 24 and the cylindrical surfaces 25 can be equal.

[0084] The sections 22 are sequentially arranged along the circumference of the shaft core 21 and connected end to end, i.e., the rolling part is an integer multiple of 3 sections 22. And along the circumference of the shaft core 21, the outer circumferential surface of all the sections 22 is cyclically arranged in the order of the arc convex surface 23, the arc concave surface 24 and the cylindrical surface 25, or in the order of the arc convex surface 23, the cylindrical surface 25 and the arc concave surface 24, so as to improve the uniformity of the rolling part and improve the rolling effect. For example, the number of the sections 22 is 6, and the outer circumferential surface of the sections 22 is sequentially arranged in the order of the arc convex surface 23, the arc concave surface 24, the cylindrical surface 25, the arc convex surface 23, the arc concave surface 24 and the cylindrical surface 25.

[0085] In some possible examples, the rolling part is divided into multiple sections, i.e., along the circumference of the shaft core 21, the central angle θ corresponding to each section 22 is equal. The product of the central angle corresponding to each section 22 and the number of the sections 22 is 360°. For example, the number of the sections 22 is 3, and the central angle corresponding to each section 22 is 120°. For another example, the number of the sections 22 is 9, and the central angle corresponding to each section 22 is 40°.

[0086] The chord length corresponding to the central angle of each section 22 is the minimum value of the average width of the convex region 13 and the average width of the concave region 12 of the film surface 11 of the plurality of battery cores 10. Wherein, the chord length corresponding to the central angle of each section 22 refers to the distance between the starting edge (S1) and the ending edge (S2) of the section 22 along the circumference of the shaft core 21, as shown as Z in FIG. 2B. According to the chord length, the central angle can be calculated, so as to determine the number of the sections 22. Figure 16

[0087] Along the axial direction of the shaft core 21, the length of each section 22 is the same, so that the two ends of each section 22 can be aligned, and thus the opposite ends of the rolling part are both flat. Along the axial direction of the shaft core 21, the opposite ends of the rolling part are annular or elliptical annular. In this way, the two ends of the plurality of sections 22 are smoothly connected along the circumference of the shaft core 21, and the plurality of sections 22 can form a relatively neat and integrated structure.

[0088] ​The compression amount of the roller pressing portion is an average of the concave depths of the concave regions 12 of the plurality of battery cells 10 or an average of the convex heights of the convex regions 13 of the plurality of battery cells 10. The hardness of the silica gel material is determined according to the compression amount of the roller pressing portion, that is, the greater the compression amount of the roller pressing portion, the greater the hardness of the silica gel material.

[0089] The roller 20 in the embodiments of the present application is used for coating the plurality of battery cells 10. The roller 20 includes a shaft core portion 21 and a roller pressing portion sleeved on the shaft core portion 21. The roller pressing portion includes at least three sub-portions 22 arranged along the circumference of the shaft core portion 21. The outer circumferential surface of each of the at least three sub-portions 22 includes an arc convex surface 23, an arc concave surface 24 and a cylindrical surface 25, and the outer circumferential surface of each of two adjacent sub-portions 22 has a different shape. In the axial direction of the shaft core portion 21, the middle part of the arc convex surface 23 protrudes away from the shaft core portion 21 relative to the two ends of the arc convex surface 23, and the middle part of the arc concave surface 24 is recessed toward the shaft core portion 21 relative to the two ends of the arc concave surface 24. The roller pressing portion includes a plurality of sub-portions 22 with different outer circumferential shapes, which can meet the requirements of different flatnesses of the plurality of battery cells 10. The arc convex surface 23, the arc concave surface 24 and the cylindrical surface 25 are used to flatten the concave regions 12 / convex regions 13 of the protective film 30 and the battery cells 10, to discharge the air between the protective film 30 and the battery cells 10, and to improve the coating reliability and yield.

[0090] The embodiments of the present application also provide a coating method. Referring to Figure 17 , the coating method specifically includes the following steps.

[0091] Step S100: a detection device detects the flatness of the coating surface of the plurality of battery cells to be coated, and obtains flatness data of the coating surface.

[0092] Referring to Figure 18 and Figure 3 , the detection device includes a 3D camera, for example, and specifically uses a 3D line scanning camera to detect the flatness of the coating surface 11 of the battery cell 10, and obtains (for example, fits to form) the flatness data. The flatness data can reflect the concave degree and convex degree of the coating surface 11 of the battery cell 10 to be coated.

[0093] Specifically, the concave degree of the coating surface 11 of the battery cell 10 includes the concave depth, width and gradient of the concave region 12. The concave depth of the concave region 12 represents the concave degree of the concave region 12, which is the size of the concave region 12 in the thickness direction (Z direction) of the battery cell 10, as shown by H1 in Figure 3 . The width of the concave region 12 represents the distribution range of the concave region 12, which is the size of the concave region 12 in the moving direction (X direction) of the battery cell 10, as shown by H2 in Figure 3 . The gradient of the concave region 12 represents the gradient of the concave region 12, which is the ratio of the concave depth to the width of the concave region 12, as shown by H3 in Figure 3 and Figure 18 . The convex degree of the coating surface 11 of the battery cell 10 includes the convex height, width and gradient of the convex region 13. The convex height of the convex region 13 represents the convex degree of the convex region 13, which is the size of the convex region 13 in the thickness direction (Z direction) of the battery cell 10, as shown by H4 in Figure 3The gradient of the recessed area 12 represents the slope of the recessed area 12, i.e. how fast the recessed area 12 changes.

[0094] The convexity of the envelope surface 11 of the battery cell 10 includes the convex height, width and gradient of the convex area 13. The convex height of the convex area 13 represents the convexity of the convex area 13, which is the dimension of the convex area 13 along the thickness direction of the battery cell 10, as shown in Figure 3 The width of the convex area 13 represents the distribution range of the convex area 13, which is the dimension of the convex area 13 along the moving direction of the battery cell 10, as shown in Figure 3 The gradient of the convex area 13 represents the slope of the convex area 13, i.e. how fast the convex area 13 changes. The gradient of the convex area 13 and the gradient of the recessed area 12 form the gradient of the flatness of the envelope surface 11 of the battery cell 10.

[0095] In step S200, a roller is formed according to the flatness data. The roller includes a shaft core part and a roller pressing part sleeved on the shaft core part. The roller pressing part includes at least three sub-parts arranged along the circumference of the shaft core part. The shape of the outer circumferential surface of the at least three sub-parts includes an arc convex surface, an arc concave surface and a cylindrical surface. The shape of the outer circumferential surface of adjacent two sub-parts is different. Along the axial direction of the shaft core part, the middle part of the arc convex surface protrudes away from the shaft core part relative to the two ends of the arc convex surface, and the middle part of the arc concave surface is recessed towards the shaft core part relative to the two ends of the arc concave surface.

[0096] Referring to Figures 4 to 16 , the roller 20 is manufactured according to the flatness data. The roller 20 includes a shaft core part 21 and a roller pressing part. The roller pressing part is sleeved on the shaft core part 21. The shaft core part 21 can be columnar. The axial direction of the shaft core part 21 is as shown by the M direction in Figure 7 , Figure 11 , Figure 15 . The circumferential direction of the shaft core part 21 is as shown by the N direction in Figure 4 , Figure 8 , Figure 12 . The material of the shaft core part 21 can be metal, so that the roller 20 has a certain hardness and can provide pressure to the battery cell 10 and the protective film 30.

[0097] The roller pressing part is sleeved outside the shaft core part 21 and is fixed relative to the shaft core part 21, for example, the two are in interference fit. Along the axial direction of the shaft core part 21, the two ends of the shaft core part 21 both protrude outside the roller pressing part, so that the shaft core part 21 can be connected to a driving mechanism outside the shaft core part 21 to drive the shaft core part 21 to rotate. The material of the roller pressing part includes silica gel material, so that the roller pressing part is soft and has a certain deformation amount, so as to ensure that the roller pressing part can be in close contact with the protective film 30 and air between the protective film 30 and the envelope surface 11 of the battery cell 10 can be discharged.

[0098] In the axial direction of the shaft core 21, the roller pressing portion includes at least three sub-portions 22 arranged in series, i.e., the number of the sub-portions 22 is greater than or equal to three. The shape of the outer circumferential surface of each of the sub-portions 22 includes an arc convex surface 23, an arc concave surface 24, and a cylindrical surface 25, and the shape of the outer circumferential surface of each of two adjacent sub-portions 22 is different, so that the roller 20 has a plurality of different outer shapes to be compatible with the requirements of a plurality of different flatnesses of the plurality of battery cells 10. In this way, the arc convex surface 23, the arc concave surface 24, and the cylindrical surface 25 can be used to flatten the concave / convex regions 12 / 13 of the protective film 30 and the battery cell 10, to discharge the air between the protective film 30 and the battery cell 10, and to improve the reliability and yield of the film wrapping.

[0099] Referring to Figures 4 to 7 , in the axial direction of the shaft core 21, the middle portion of the arc convex surface 23 protrudes away from the shaft core 21 relative to the two ends of the arc convex surface 23. As shown in Figure 7 , in the axial direction of the shaft core 21, the distance between the arc convex surface 23 and the axis (O-O shown) of the shaft core 21 first increases and then decreases. The intersection line of the plane containing the axis of the shaft core 21 and the arc convex surface 23 is an outward convex arc line, i.e., the intersection line is an outer circular arc.

[0100] In the axial direction of the shaft core 21, the height of the highest point of the arc convex surface 23 is the maximum value in the concave depth of the concave region 12 of the film wrapping surface 11 of each battery cell 10. In this way, the height of the arc convex surface 23 is greater than or equal to the concave depth of the concave region 12 of the film wrapping surface 11 of each battery cell 10, so that the arc convex surface 23 and the concave region 12 are adapted in the radial direction of the shaft core 21.

[0101] Referring to Figures 8 to 11 , in the axial direction of the shaft core 21, the middle portion of the arc concave surface 24 is recessed away from the shaft core 21 relative to the two ends of the arc concave surface 24. As shown in Figure 11 , in the axial direction of the shaft core 21, the distance between the arc concave surface 24 and the axis (O-O shown) of the shaft core 21 first increases and then decreases. The intersection line of the plane containing the axis of the shaft core 21 and the arc concave surface 24 is an inward concave arc line, i.e., the intersection line is an inner circular arc.

[0102] In the axial direction of the shaft core 21, the depth of the lowest point of the arc concave surface 24 is the maximum value in the convex height of the convex region 13 of the film wrapping surface 11 of each battery cell 10. In this way, the depth of the arc concave surface 24 is greater than or equal to the convex height of the convex region 13 of the film wrapping surface 11 of each battery cell 10, so that the arc concave surface 24 and the convex region 13 are adapted in the radial direction of the shaft core 21.

[0103] Referring to Figures 12 to 15 , the cylindrical surface 25 is a circular cylindrical surface 25, and in the axial direction of the shaft core 21, the distance between the cylindrical surface 25 and the axis (O-O shown) of the shaft core 21 is equal. The intersection line of the plane containing the axis of the shaft core 21 and the arc concave surface 24 is a straight line.

[0104] The compression amount of the rolling part is the average of the depths of the recessed areas 12 of the plurality of battery cells 10 or the average of the heights of the raised areas 13 of the plurality of battery cells 10. The hardness of the silicone material is determined by the compression amount of the rolling part. That is, the greater the compression amount of the rolling part, the greater the hardness of the silicone material.

[0105] In some possible examples, the rolling portion is divided into a plurality of sub-sections 22. That is, along the circumference of the shaft core 21, the central angle θ corresponding to each sub-section 22 is equal. The product of the central angle corresponding to each sub-section 22 and the number of sub-sections 22 is 360°. For example, there are three sub-sections 22, and the central angle corresponding to each sub-section 22 is 120°. For another example, there are nine sub-sections 22, and the central angle corresponding to each sub-section 22 is 40°.

[0106] The chord length corresponding to the central angle of each segment 22 is the minimum value of the average value of the width of the raised area 13 and the average value of the width of the recessed area 12 of the coating surface 11 of the plurality of battery cells 10. The chord length corresponding to the central angle of each segment 22 refers to the distance between the starting edge (S1) and the ending edge (S2) of the segment 22 along the circumference of the axial core 21, as shown in FIG. Figure 16 As shown in Z.

[0107] The average width of the raised area 13 of the coating surface 11 of the plurality of battery cells 10 is taken as the average width Y1 of the raised area 13. 均 The average width of the concave area 12 of the coating surface 11 of the plurality of battery cells 10 is taken as the average width Y2 of the concave area 12. 均 Take the average width Y1 of the raised area 13 均 and the average width Y2 of the recessed area 12 均 The minimum value of the chord length is min(Y1 均 , Y2 均 )=Z, the central angle of the circle can be determined according to Z, thereby determining the number of the sections 22.

[0108] In this way, the average width Y1 of the raised area 13 of the coating surface 11 of the plurality of battery cells 10 is 均 and the average width Y2 of the recessed area 12 均The minimum value in the above formula is taken as the basis for the equal division of the roller 20, so that the outer circumferential surface of the formed part 22 can be maximally ensured to contact the convex region 13 / depressed region 12 of the film surface 11, and the fitting degree of the outer circumferential surface of different parts 22 and the convex region 13 / depressed region 12 of the film surface 11 of the plurality of battery cells 10 is better. Among them, the part 22 with the arc-shaped concave surface 24 is used to cooperate with the convex region 13 of the film surface 11 of the battery cell 10, so as to ensure that the protective film 30 can be better wrapped on the convex region 13 of the film surface 11 of the battery cell 10. The part 22 with the arc-shaped convex surface 23 is used to cooperate with the depressed region 12 of the film surface 11 of the battery cell 10, so as to ensure that the protective film 30 can be better wrapped on the depressed region 12 of the film surface 11 of the battery cell 10.

[0109] In some possible examples, the number of parts 22 is an integer multiple of 3; along the circumference of the shaft core 21, the shapes of the outer circumferential surfaces of all parts 22 are cyclically arranged, and are in turn arc-shaped convex surfaces 23, arc-shaped concave surfaces 24 and cylindrical surfaces 25, or are in turn arc-shaped convex surfaces 23, cylindrical surfaces 25 and arc-shaped concave surfaces 24. For example, the number of parts 22 is 3, 6, 9, etc., so that the number of arc-shaped convex surfaces 23, arc-shaped concave surfaces 24 and cylindrical surfaces 25 can be equal.

[0110] These parts 22 are sequentially arranged along the circumference of the shaft core 21, and are connected end to end, that is, the roller-pressing part is an integer multiple of 3 parts 22. And along the circumference of the shaft core 21, the outer circumferential surfaces of all parts 22 are cyclically arranged according to arc-shaped convex surfaces 23, arc-shaped concave surfaces 24 and cylindrical surfaces 25, or are cyclically arranged according to arc-shaped convex surfaces 23, cylindrical surfaces 25 and arc-shaped concave surfaces 24, so as to improve the uniformity of the roller-pressing part and improve the roller-pressing effect. For example, the number of parts 22 is 6, and the outer circumferential surfaces of these parts 22 are in turn arc-shaped convex surfaces 23, arc-shaped concave surfaces 24, cylindrical surfaces 25, arc-shaped convex surfaces 23, arc-shaped concave surfaces 24 and cylindrical surfaces 25.

[0111] Step S300: The conveying mechanism sends the battery cell to contact the protective film, and uses the roller to press the protective film on the battery cell.

[0112] Referring to Figure 18 , the conveying mechanism conveys the battery cell 10 to the film-coating station, so that the battery cell 10 and the protective film 30 are in contact, and the battery cell 10 and the protective film 30 are also driven to pass through the area where the roller 20 is located. The roller 20 is arranged on both sides of the large face of the battery cell 10, that is, the roller 20 includes an upper roller and a lower roller, and the battery cell 10 and the protective film 30 pass between the upper roller and the lower roller. The upper roller coats the film surface 11 on the top of the battery cell 10, and the lower roller coats the film surface 11 on the bottom of the battery cell 10.

[0113] One end of the roller 20 is connected to a driving mechanism, such as a servo motor, and the other end of the roller 20 is connected to a rotating shaft. After receiving a start signal, the driving mechanism drives the roller 20 to rotate, so that the different profile surfaces of the roller 20 reciprocate and roll the protective film 30, so as to adapt to the flatness of different battery cells 10, so that the battery cell 10 is coated with a film, and the roller 20 stops rotating after the coating is completed. The driving mechanism controls the rotating speed of the roller 20.

[0114] The rotating speed of the roller 20 can be adjusted, which is specifically adjusted in real time according to the flatness gradient. The greater the flatness gradient, the greater the rotating speed of the roller 20. In this way, the roller 20 can be self-adaptively adjusted according to the flatness of the battery cell 10, so as to adapt to the coating surface 11 of various battery cells 10, and ensure that the roller 20 can flatten the concave area 12 and the convex area of the protective film 30 and the battery cell 10, realize self-adaptive compatibility of various battery cells 10, and ensure the coating effect.

[0115] Specifically, the moving speed of the battery cell 10 is E (mm / s), the rotating speed of the roller 20 is F (rpm / s), the number of rotations of the roller 20 per unit length along the moving direction of the battery cell 10 is G, F=G / (1 / E), and G≥1, so that the entire outer periphery of the roller 20 is in contact with the protective film 30 per unit length of the battery cell 10. The value of G determines the number of times that the different profile surfaces of the roller 20 contact the protective film 30, thereby determining the self-adaptive range of the entire outer periphery of the roller 20 to the flatness of the battery cell 10. According to the flatness gradient of different battery cells 10 tested on site, the relationship between the flatness gradient of the battery cell 10 and the rotating speed F of the roller 20 is calculated to form a corresponding relationship list.

[0116] In the example in which the roller 20 includes an upper roller and a lower roller, the rotating speeds of the upper roller and the lower roller can be adjusted respectively, which are adapted to the flatness of the corresponding coating surface 11. In some possible embodiments, the coating method further includes: a detection device detects the coating effect of the battery cell 10, and optimizes the relationship between the rotating speed of the roller 20 and the flatness gradient, so as to further improve the self-adaptive compatibility of the roller 20 to the battery cell 10.

[0117] Referring to Figure 18 and Figure 19 , the coating method specifically includes the following processes:

[0118] The battery cell 10 is conveyed to a detection station on a production line;

[0119] A 3D camera is used to detect the flatness of the coating surface 11 of the battery cell 10, and flatness data is obtained;

[0120] The battery cell 10 after detection is fed by a conveying mechanism, and the battery cell 10 is positioned;

[0121] A gripper is used to pick up the positioned battery cell 10, and convey the battery cell 10 to a coating station at a set speed;

[0122] The bottom of the battery cell 10 contacts the protective film 30. According to the flatness data of the film-coated surface 11 of the battery cell 10, the roller 20 dynamically adjusts the rotating speed in real time, and presses the protective film 30 in the direction perpendicular to the film-coated surface 11 of the battery cell 10 (from top to bottom);

[0123] The battery cell 10 continues to advance. According to the flatness data of the film-coated surface 11 of the battery cell 10, the roller 20 dynamically adjusts the rotating speed in real time, and presses the protective film 30 in the direction opposite to the advancing direction of the battery cell 10 (from front to back), while the protective film 30 is being cut;

[0124] The battery cell 10 after film coating is transmitted to a detection station, and a 3D camera is used to detect the film coating effect;

[0125] According to the film coating detection result, the rotating speed and the flatness gradient relationship are re-optimized.

[0126] In the film coating method in the embodiments of the present application, the flatness of the film-coated surface 11 of the plurality of battery cells 10 to be film-coated is detected by a detection device, the flatness data of the film-coated surface 11 is obtained, and a roller 20 is formed using the flatness data. The protective film 30 is wrapped on the battery cell 10 by using the roller 20. The roller 20 includes a shaft core part 21 and a roller pressing part sleeved on the shaft core part 21. The roller pressing part includes at least three sub-parts 22 arranged along the circumference of the shaft core part 21. The outer circumferential surface of the at least three sub-parts 22 includes an arc convex surface 23, an arc concave surface 24 and a cylindrical surface 25. The shapes of the outer circumferential surfaces of adjacent two sub-parts 22 are different. In the axial direction of the shaft core part 21, the middle part of the arc convex surface 23 protrudes away from the shaft core part 21 relative to the two ends of the arc convex surface 23, and the middle part of the arc concave surface 24 is recessed towards the shaft core part 21 relative to the two ends of the arc concave surface 24. The roller pressing part includes a plurality of sub-parts 22 with different outer circumferential shapes, which can meet the needs of different flatness of the plurality of battery cells 10. The arc convex surface 23, the arc concave surface 24 and the cylindrical surface 25 are used to press the recessed area 12 / protruding area 13 of the protective film 30 and the battery cell 10, to discharge the air between the protective film 30 and the battery cell 10, and to improve the film coating reliability and yield.

[0127] Finally, it should be noted that: other embodiments of the application will occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. The present application is intended to cover any variations, uses or adaptive changes of the present application that follow the general principles of the present application and include common knowledge or conventional technical means in the art that are not disclosed by the present application, and is not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present application is only limited by the appended claims.

Claims

1. A roller, characterized in that: Used for coating a plurality of battery cells (10), the roller (20) comprises: an axis core portion (21), and a rolling portion sleeved on the axis core portion (21); The rolling portion comprises at least three sections (22) arranged along the circumference of the shaft core (21), the outer peripheral surfaces of the at least three sections (22) having shapes including an arcuate convex surface (23), an arcuate concave surface (24) and a cylindrical surface (25), and the shapes of the outer peripheral surfaces of two adjacent sections (22) are different; Wherein, along the axial direction of the shaft core portion (21), the middle portion of the arcuate convex surface (23) is convex in a direction away from the shaft core portion (21) relative to the two ends of the arcuate convex surface (23), and the middle portion of the arcuate concave surface (24) is concave in a direction close to the shaft core portion (21) relative to the two ends of the arcuate concave surface (24).

2. The roller according to claim 1, characterized in that One end of two adjacent subsections (22) adjacent to each other is in an arc transition.

3. The roller according to claim 1, characterized in that The material of the rolling part includes silicone material.

4. The roller according to claim 1, characterized in that Along the axial direction of the shaft core (21), the two opposite ends of the rolling portion are in the shape of a circular ring or an elliptical ring.

5. The roller according to any one of claims 1 to 4, characterized in that: The number of the subsections (22) is an integer multiple of 3; Along the circumference of the shaft core (21), the shapes of the outer peripheral surfaces of all the subdivisions (22) are arranged in a cyclic manner, and are sequentially an arc-shaped convex surface (23), an arc-shaped concave surface (24), and a cylindrical surface (25), or sequentially an arc-shaped convex surface (23), a cylindrical surface (25), and an arc-shaped concave surface (24).

6. The roller according to any one of claims 1 to 4, characterized in that: The rolling section is divided into a plurality of sections (22).

7. The roller according to claim 6, characterized in that The chord length corresponding to the central angle of each of the subsections (22) is the minimum value of the average value of the width of the raised area (13) and the average value of the width of the recessed area (12) of the coating surface (11) of the plurality of battery cells (10).

8. The roller according to any one of claims 1 to 4, characterized in that: The depth of the lowest point of the arc-shaped concave surface (24) is the maximum value among the convex heights of the convex areas (13) of the coating surfaces (11) of the plurality of battery cells (10).

9. The roller according to any one of claims 1 to 4, characterized in that: The height of the highest point of the arc-shaped convex surface (23) is the maximum value among the recessed depths of the recessed areas (12) of the envelope surfaces (11) of the plurality of battery cells (10).

10. The roller according to any one of claims 1 to 4, characterized in that: The compression amount of the rolling portion is an average value of the concave depths of the concave regions (12) of the plurality of battery cells (10), or an average value of the convex heights of the convex regions (13) of the plurality of battery cells (10).

11. The roller according to any one of claims 1 to 4, characterized in that: Along the axial direction of the shaft core (21), the lengths of the subsections (22) are the same.

12. A film coating device, characterized in that: include: A conveying mechanism, a roller (20) according to any one of claims 1 to 10, and a driving mechanism; The conveying mechanism is used to convey the battery core (10), and the driving mechanism is in transmission connection with the roller (20) to drive the roller (20) to rotate.

13. A coating method, characterized in that: include: The detection device detects the flatness of the coating surface (11) of the plurality of battery cells (10) to be coated, and obtains flatness data of the coating surface (11); A roller (20) is formed according to the flatness data, wherein the roller (20) comprises: an axial core portion (21), and a rolling portion sleeved on the axial core portion (21); the rolling portion comprises at least three sub-portions (22) arranged along the circumference of the axial core portion (21); the shapes of the outer peripheral surfaces of the at least three sub-portions (22) comprise an arcuate convex surface (23), an arcuate concave surface (24) and a cylindrical surface (25), and the shapes of the outer peripheral surfaces of two adjacent sub-portions (22) are different; wherein, along the axial direction of the axial core portion (21), the middle portion of the arcuate convex surface (23) is convex relative to the two ends of the arcuate convex surface (23) in a direction away from the axial core portion (21), and the middle portion of the arcuate concave surface (24) is concave relative to the two ends of the arcuate concave surface (24) in a direction close to the axial core portion (21); The conveying mechanism conveys the battery core (10) to contact the protective film (30), and utilizes the roller (20) to press the protective film (30) onto the battery core (10).

14. The coating method according to claim 13, characterized in that: The flatness data includes a flatness gradient, and when the protective film (30) is pressed onto the battery core (10), the rotation speed of the roller (20) is adjusted in real time according to the flatness gradient.

15. The coating method according to claim 14, characterized in that: Also includes: The detection device detects the coating effect of the battery core (10) and optimizes the relationship between the rotation speed of the roller (20) and the flatness gradient.

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