A lamination device

Abstract

The present invention relates to the field of battery technology, and discloses a lamination device. The lamination device includes a lamination table, a pressing plate, and a driving device. The lamination table is used to place pole pieces, and the pole pieces stacked on the lamination table include a first pole piece, and the pole ear of the first pole piece has a first end angle; the pressing plate has a smoothing portion, and the smoothing portion protrudes from the surface of the pressing plate; the driving device is connected to the pressing plate, and is used to drive the pressing plate to be pulled out from the bottom of the pole piece in a direction away from the lamination table, and pressed against the top of the pole piece; when the pressing plate is pressed against the top of the pole piece, the orthographic projection of the pressing plate on the plane where the lamination table is located covers the orthographic projection of the first end angle on the plane where the lamination table is located; the moving trajectory of the orthographic projection of the smoothing portion on the plane where the lamination table is located covers the orthographic projection of the first end angle on the plane where the lamination table is located; when the first end angle is bent toward the side where the smoothing portion is located, the smoothing portion can push the first end angle to expand outward during the movement, thereby stretching, so that the folding phenomenon of the pole ear is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a lamination device. Background Art

[0002] In the process of making lithium-ion batteries, the positive and negative electrodes need to be alternately stacked to form semi-finished battery cells. Both the positive and negative electrodes include a current collector and an active material covering the surface of the current collector, wherein the portion of the current collector not covered by the active material forms a tab. For the negative electrode, copper foil is usually used as the current collector. Since copper foil is soft in texture, the tab of the negative electrode is prone to warping at the end corners. When the negative electrode is stacked into the battery cell, the tab of the negative electrode is prone to folding at the end corners, resulting in a large proportion of abnormal self-discharge of the battery cell, which in turn affects the qualified rate of the battery cell. Summary of the invention

[0003] The present invention provides a lamination device for solving the problem in the prior art that the tabs of the negative electrode sheets are prone to be folded at the end corners, resulting in a large proportion of abnormal self-discharge of the manufactured battery cells.

[0004] The present invention provides a lamination device, which comprises a lamination table, a pressing plate and a driving device; wherein:

[0005] The lamination platform is used to place pole pieces, and the pole pieces have a material area and a pole ear; and the pole pieces stacked on the lamination platform include a first pole piece, and the pole ear of the first pole piece has a first end angle;

[0006] The pressing plate has a smoothing portion, and the smoothing portion protrudes from the surface of the pressing plate;

[0007] The driving device is connected to the pressing plate, and is used for driving the pressing plate to be pulled out from the bottom of the pole piece in a direction away from the lamination table and pressed against the top of the pole piece; when the pressing plate is pressed against the top of the pole piece, the orthographic projection of the pressing plate on the plane where the lamination table is located covers the orthographic projection of the first end angle on the plane where the lamination table is located; the moving trajectory of the orthographic projection of the smoothing portion on the plane where the lamination table is located covers the orthographic projection of the first end angle on the plane where the lamination table is located; when the first end angle is bent toward the side where the smoothing portion is located, the smoothing portion is used to smooth the first end angle.

[0008] The lamination equipment provided by the present invention has at least the following beneficial effects:

[0009] In the above-mentioned lamination equipment, the pressing plate has a smoothing portion, and the smoothing portion protrudes from the surface of the pressing plate, so that the surface of the pressing plate is uneven. During the process of pulling out the pressing plate, the smoothing portion will move with the pressing plate. When the smoothing portion contacts the first end angle of the pole ear, the smoothing portion easily lifts the first end angle, so that the first end angle opens outward under the push of the smoothing portion, thereby stretching. In this way, during the lamination process, the folding phenomenon of the pole ear is improved, the risk of abnormal self-discharge of the manufactured battery cell is reduced, and the yield rate of the battery cell is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A schematic diagram of the structure of a lamination device provided in an embodiment of the present invention;

[0011] Figure 2 A schematic diagram of a lamination provided in an embodiment of the present invention;

[0012] Figure 3 A schematic diagram of smoothing a first end angle by a pressing plate provided in an embodiment of the present invention;

[0013] Figure 4 A schematic diagram of the positional relationship between the orthographic projection of the pressing plate on the surface of the lamination table and the orthographic projection of the pole piece on the surface of the lamination table provided in an embodiment of the present invention;

[0014] Figure 5 A schematic diagram of another positional relationship between the orthographic projection of the pressing plate on the surface of the lamination table and the orthographic projection of the pole piece on the surface of the lamination table provided in an embodiment of the present invention;

[0015] Figure 6 A schematic diagram of the structure of a pressing plate provided in an embodiment of the present invention;

[0016] Figure 7 A schematic diagram of a cross section of a first surface perpendicular to a first direction Y provided in an embodiment of the present invention;

[0017] Figure 8 Another structural schematic diagram of a pressing plate provided in an embodiment of the present invention.

[0018] Reference numerals:

[0019] 10- lamination table; 20- pole piece;

[0020] 201- material area; 202- pole ear;

[0021] 203-first end angle; 204-first edge;

[0022] 21-first pole piece; 22-pole piece a;

[0023] 23-pole piece b; 24-pole piece c;

[0024] 30-pressing plate; 31-first pressing plate;

[0025] 32-second pressing plate; 301-first end;

[0026] 302-second end; 303-first side;

[0027] 304-second side; 40-smoothing part;

[0028] 401-first surface; 402-third end;

[0029] 403- fourth end; 50- driving device. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Figure 1 A schematic diagram of a structure of a lamination device provided in an embodiment of the present invention, such as Figure 1 As shown, in one embodiment, the lamination equipment includes a lamination platform 10, and the lamination platform 10 is used to place the electrode sheet 20. The electrode sheet 20 includes a positive electrode skin and a negative electrode sheet. During the lamination process, the positive electrode sheet and the negative electrode sheet are alternately placed on the lamination platform 10. The electrode sheet 20 has a material area 201 and a pole ear 202. The material area 201 includes a current collector and an active material covered on the surface of the current collector, and the pole ear 202 only includes the current collector. For the positive electrode sheet and the negative electrode sheet stacked on the lamination platform 10, the orthographic projection of the material area 201 of the positive electrode sheet on the plane where the lamination platform 10 is located and the orthographic projection of the material area 201 of the negative electrode sheet on the plane where the lamination platform 10 is located overlap, and the orthographic projection of the pole ear 202 of the positive electrode sheet on the plane where the lamination platform 10 is located and the orthographic projection of the pole ear 202 of the negative electrode sheet on the plane where the lamination platform 10 is located are respectively located at the opposite ends of the above-mentioned overlapping area.

[0032] Please continue to refer to Figure 1, the lamination equipment also includes a pressing plate 30 and a driving device 50. The function of the pressing plate 30 is to press the pole piece 20 transferred to the lamination table 10, so as to reduce the misalignment of the pole piece 20 during the lamination process and improve the alignment of the pole piece 20. The pressing plate 30 is connected to the driving device 50. Driven by the driving device 50, the pressing plate 30 can be pulled out from the bottom of the pole piece 20 in a direction away from the lamination table 10 and pressed against the top of the pole piece 20. The pole piece 20 is a positive pole piece or a negative pole piece that appears in the lamination sequence during the lamination process. In one embodiment, the lamination equipment includes four pressing plates 30, two of which are located at the same end as the pole piece 202 of the positive pole piece, and the other two pressing plates 30 are located at the same end as the pole piece 202 of the negative pole piece. During the lamination process, the two pressing plates 30 located at the same end as the tab 202 of the positive electrode sheet perform the above-mentioned action alternately, and the two pressing plates 30 located at the same end as the tab 202 of the negative electrode sheet perform the above-mentioned action alternately.

[0033] In order to clearly describe the action of the pressing plate 30 during the lamination process, two pressing plates 30 located at the same end are taken as an example for explanation. Figure 2 A schematic diagram of a lamination provided by an embodiment of the present invention, such as Figure 2 As shown, the two pressing plates 30 are respectively the first pressing plate 31 and the second pressing plate 32. At the first moment, the lamination platform 10 has a pole piece a22, the first pressing plate 31 is located below the pole piece a22, and the second pressing plate 32 is located above the pole piece a22. At the second moment, the lamination platform 10 has a newly placed pole piece b23, and the polarity of the pole piece b23 is opposite to that of the pole piece a22. Then, the second pressing plate 32 is kept stationary, the first pressing plate 31 is pulled out, and then pressed against the surface of the pole piece b23. At the third moment, the lamination platform 10 has a newly placed pole piece c24, and the polarity of the pole piece c24 is opposite to that of the pole piece b23. Then, the first pressing plate 31 is kept stationary, the second pressing plate 32 is pulled out, and then pressed against the surface of the pole piece c24. During the lamination process, the first pressing plate 31 and the second pressing plate 32 perform the above actions alternately, in a reciprocating cycle.

[0034] For reference Figure 1 and Figure 2 The pole piece 20 stacked on the lamination table 10 includes a first pole piece 21, and the pole ear 202 of the first pole piece 21 has a first end angle 203. The first pole piece 21 can be a positive pole piece or a negative pole piece. Before the pressing plate 30 is pulled out, the first pole piece 21 is in contact with the pressing plate 30. During the lamination process, the first pole piece 21 may be located above the pressing plate 30 or below the pressing plate 30. When the pressing plate 30 is pressed against the top of the pole piece 20, the orthographic projection of the pressing plate 30 on the plane where the lamination table 10 is located covers the orthographic projection of the first end angle 203 on the plane where the lamination table 10 is located.

[0035] The pressing plate 30 has a smoothing portion 40, and the smoothing portion 40 protrudes from the surface of the pressing plate 30. The first pole piece 21 and the smoothing portion 40 are located on the same side of the pressing plate 30, and when the pressing plate 30 is pressed against the top of the pole piece 20, the orthographic projection of the smoothing portion 40 on the plane where the lamination table 10 is located and the orthographic projection of the pole ear 202 of the first pole piece 21 on the plane where the lamination table 10 is located at least partially overlap. Moreover, during the process of pulling out the pressing plate 30, the moving trajectory of the orthographic projection of the smoothing portion 40 on the plane where the lamination table 10 is located can cover the orthographic projection of the first end angle 203 on the plane where the lamination table 10 is located. In other words, the smoothing portion 40 can sweep over the first end angle 203. When the first end angle 203 is folded toward the side where the smoothing portion 40 is located, the smoothing portion 40 can drive the first end angle 203 to unfold during the movement, thereby smoothing the first end angle 203.

[0036] Figure 3 A schematic diagram of a first end angle smoothed by a pressing plate provided in an embodiment of the present invention, such as Figure 3 As shown, the direction indicated by the arrow is the direction of withdrawal of the pressing plate 30. When the pressing plate 30 is withdrawn in the above direction, the smoothing portion 40 will move with the pressing plate 30 and sweep across the surface of the tab 202. When the smoothing portion 40 contacts the first end corner 203 of the tab 202, the smoothing portion 40 easily lifts the first end corner 203, so that the first end corner 203 is pushed outward by the smoothing portion 40, thereby stretching. In this way, during the lamination process, the folding phenomenon of the first end corner 203 is improved, the risk of abnormal self-discharge of the battery cell is reduced, and the yield rate of the battery cell is improved.

[0037] In order to reduce the risk of the smoothing portion 40 scratching the material area 201 of the first pole piece 21 and causing the active material in the material area 201 to fall off during the withdrawal of the pressing plate 30, in one embodiment, when the pressing plate 30 is pressed against the top of the pole piece 20, the smoothing portion 40 is located on the side of the boundary between the material area 201 of the first pole piece 21 and the pole ear 202 away from the material area 201 of the first pole piece 21. In other words, with respect to the first pole piece 21, the orthographic projection of the smoothing portion 40 on the plane where the lamination table 10 is located and the orthographic projection of the material area 201 on the plane where the lamination table 10 is located do not overlap. In this way, during the withdrawal of the pressing plate 30, the smoothing portion 40 will not contact the material area 201, thereby reducing the risk of the material area 201 being scratched by the smoothing portion 40.

[0038] When the pressing plate 30 is specifically set, the pressing plate 30 should have a relatively large hardness, so that the pressing plate 30 is not easily deformed and can provide a relatively large pressure for the pole piece 20. The pressing plate 30 can be made of metal or non-metal, which is not limited in this application. The shape of the pressing plate 30 includes a variety of options, for example, the pressing plate 30 can be rectangular, circular, elliptical or irregular.

[0039] Figure 4A schematic diagram of the positional relationship between the orthographic projection of the pressing plate on the surface of the lamination table and the orthographic projection of the pole piece on the surface of the lamination table provided in an embodiment of the present invention, Figure 5 Another schematic diagram of the positional relationship between the orthographic projection of the pressing plate on the surface of the lamination table and the orthographic projection of the pole piece on the surface of the lamination table provided in an embodiment of the present invention is as follows: Figure 4 and Figure 5 As shown, in some embodiments, the pressing plate 30 has a first end 301 and a second end 302 that are arranged opposite to each other, wherein the first end 301 is used to connect with the driving device 50. Before the pressing plate 30 is pulled out, the orthographic projection of the first end 301 on the plane where the lamination platform 10 is located is located outside the orthographic projection of the pole piece 20 on the surface of the lamination platform 10, and the orthographic projection of the second end 302 on the plane where the lamination platform 10 is located and the orthographic projection of the pole piece 20 on the surface of the lamination platform 10 at least partially overlap.

[0040] Optionally, for any electrode sheet 20, the orthographic projection of the second end 302 on the surface of the lamination platform 10 and the orthographic projection of the material area 201 of the electrode sheet 20 on the surface of the lamination platform 10 at least partially overlap. During the lamination process, when the pressing plate 30 is pressed against the surface of the negative electrode sheet, the pressing plate 30 presses the material area 201 and the tab 202 of the negative electrode sheet. When the pressing plate 30 is pressed against the surface of the positive electrode sheet, the pressing plate 30 presses the material area 201 of the positive electrode sheet. In other words, the pressing plate 30 can press the electrode sheet whether it is a positive electrode sheet or a negative electrode sheet.

[0041] Please continue to refer to Figure 4 In addition to the first end 301 and the second end 302, the pressing plate 30 also has a first edge 303, and the first edge 303 is located between the first end 301 and the second end 302. Before the pressing plate 30 is pulled out, the orthographic projection of the first edge 303 on the plane where the lamination stage 10 is located intersects with the orthographic projection of the pole piece 20 on the plane where the lamination stage 10 is located, or the orthographic projection of the first edge 303 on the plane where the lamination stage 10 is located is located outside the orthographic projection of the pole piece 20 on the plane where the lamination stage 10 is located.

[0042] Specifically, the pole piece 20 has a first edge 204, a portion of which is located in the material area 201, and another portion of which is located in the pole ear 202. When the pressing plate 30 presses the pole piece 20, the first edge 303 and the first edge 204 have a variety of positional relationships. For example, Figure 4 As shown, in one embodiment, the orthographic projection of the first edge 303 on the plane where the lamination platform 10 is located coincides with the orthographic projection of the first edge 204 on the plane where the lamination platform 10 is located. At this time, the orthographic projection of the first edge 303 on the plane where the lamination platform 10 is located intersects with the orthographic projection of the pole piece 20 on the plane where the lamination platform 10 is located.

[0043] like Figure 5As shown, in another embodiment, the orthographic projection of the first edge 303 on the plane where the lamination stage 10 is located is located outside the orthographic projection of the first edge 204 on the plane where the lamination stage 10 is located. At this time, the orthographic projection of the first edge 303 on the plane where the lamination stage 10 is located and the orthographic projection of the pole piece 20 on the plane where the lamination stage 10 are located do not intersect.

[0044] For the pole piece 20 whose pole ear 202 and the pressing plate 30 are located at the same end of the lamination table 10 , in the above embodiment, the orthographic projection of the pressing plate 30 on the plane where the lamination table 10 is located can completely cover an end corner of the pole ear 202 of the pole piece 20 .

[0045] In another embodiment, the orthographic projection of the first edge 303 on the plane where the stacking table 10 is located is located on the inner side of the orthographic projection of the first edge 204 on the plane where the stacking table 10 is located. At this time, the orthographic projection of the first edge 303 on the plane where the stacking table 10 is located intersects with the orthographic projection of the pole piece 20 on the plane where the stacking table 10 is located.

[0046] When the smoothing portion 40 is specifically configured, the smoothing portion 40 includes various structural forms. Figure 6 A schematic diagram of the structure of a pressing plate provided in an embodiment of the present invention, such as Figure 6 As shown, in one embodiment, the smoothing portion 40 is a strip-shaped structure. The smoothing portion 40 extends along the first direction Y, and the dimension of the smoothing portion 40 along the first direction Y is much larger than the dimension of the smoothing portion 40 perpendicular to the first direction Y.

[0047] In another embodiment, the smoothing portion 40 includes at least one convex hull. Optionally, the convex hull may be cylindrical, hemispherical, semi-ellipsoidal or irregular in shape. The number of convex hulls may be one, two, three or other numbers, which may be set according to actual needs in specific applications, and the present application does not limit it. In a specific embodiment, the smoothing portion 40 includes a plurality of convex hulls. When specifically arranging the plurality of convex hulls, the plurality of convex hulls may be lined up in a row along a set direction, or the plurality of convex hulls may be arranged in multiple rows, and two adjacent rows may be aligned or staggered.

[0048] Of course, in addition to the above-mentioned structural forms, the smoothing portion 40 may also include other structural forms, which are not listed one by one in this application.

[0049] In order to reduce the damage caused by the smoothing portion 40 to the first pole piece 21 during the process of withdrawing the pressing plate 30, as shown in FIG. Figure 6As shown, in one embodiment, the flattening portion 40 has a first surface 401. The first surface 401 protrudes away from the pressing plate 30, and the first surface 401 is a curved surface. Before the pressing plate 30 is withdrawn, the first surface 401 faces the first pole piece 21 and is in contact with the first pole piece 21. During the process of withdrawing the pressing plate 30, since the first surface 401 is relatively smooth and has no edges, the damage caused by the flattening portion 40 to the first pole piece 21 is reduced.

[0050] Please continue to refer to Figure 6 , in one embodiment, the first surface 401 extends along the first direction Y. The first surface 401 is arched. The first surface 401 has two side edges, and these two side edges respectively extend along the first direction Y and are connected to the pressing plate 30. The part located between these two side edges protrudes away from the pressing plate 30. The cross-section of the first surface 401 perpendicular to the first direction Y includes various shapes. For example, the above cross-section can be an arc, an elliptical arc, or an irregular arc.

[0051] Figure 7 FIG. is a schematic diagram of a cross-section of the first surface perpendicular to the first direction Y provided by an embodiment of the present invention. As Figure 7 shown, in one embodiment, the cross-section of the first surface 401 perpendicular to the first direction Y is an elliptical arc. The eccentricity of the elliptical arc is e, and 0 < e < 1. If the major axis corresponding to the elliptical arc is located on the Z axis and the minor axis corresponding to the elliptical arc is located on the X axis, the smaller the value of e, the closer the elliptical arc is to an arc, and the less likely it is to flatten the tab; the larger the value of e, the flatter the elliptical arc, and the sharper the end of the elliptical arc away from the pressing plate 30, and the more likely it is to scratch the tab. It should be noted that the above X axis is parallel to the surface of the pressing plate 30 and perpendicular to the first direction Y, and the above Z axis is perpendicular to the surface of the pressing plate 30.

[0052] In a specific embodiment, e satisfies the following formula: 0.5 ≤ e ≤ 0.8. Optionally, the value of e can be 0.55, 0.6, 0.65, 0.7, 0.75 or other values within the above range, and the present application does not list them one by one. Within the above range, the first surface 401 has a more suitable shape, so that the flattening portion 40 has a better flattening effect and reduces the scratching of the tab by the flattening portion 40.

[0053] For the flattening portion 40 having a bar-shaped structure, when specifically arranging the flattening portion 40, there are various arrangement methods with respect to the first side 303 of the pressing plate 30. As Figure 6 shown, in one embodiment, the above flattening portion 40 is inclined with respect to the first side 303. During the process of withdrawing the pressing plate 30, the above flattening portion 40 moves parallel in a posture inclined with respect to the first side 303 and sweeps across the surface of the tab 202.

[0054] Figure 8 Another structural schematic diagram of a pressing plate provided in an embodiment of the present invention is shown in FIG. Figure 8 As shown, in another embodiment, the smoothing portion 40 is disposed perpendicular to the first edge 303. In the process of withdrawing the pressing plate 30, the smoothing portion 40 moves parallel to the first edge 303 and sweeps across the surface of the tab 202.

[0055] In order to reduce the damage caused by the smoothing portion 40 to the first end corner 203 during the smoothing process of the first end corner 203, as shown in FIG. Figure 6 As shown, in one embodiment, the smoothing portion 40 is inclined relative to the first edge 303, and the distance from the smoothing portion 40 to the first edge 303 gradually decreases along the direction from the first end 301 to the second end 302. The inclination direction of the smoothing portion 40 is substantially the same as the inclination direction of the crease generated when the first end corner 203 is bent. When the smoothing portion 40 sweeps over the first end corner 203, the smoothing portion 40 can contact the surface of the first end corner 203, thereby pushing the first end corner 203 to expand outward, reducing the risk of the edge of the first end corner 203 being damaged by tearing.

[0056] If represents the angle between the extension direction (first direction Y) of the smoothing portion 40 and the first side 303, then The larger the value of is, the larger the area swept by the smoothing portion 40 is; The smaller the value of is, the smaller the area swept by the smoothing portion 40 is. In one embodiment, Satisfy the following formula: 50°≤ ≤60°, so that the area swept by the smoothing portion 40 is larger, and the extension direction of the smoothing portion 40 is close to the inclination direction of the fold generated when the first end angle 203 is bent. The value of can be 51°, 52°, 53°, 54°, 55°, 56°, 57°, 58°, 59° or other values ​​that satisfy the above range, which are not listed one by one in this application.

[0057] Relative to the first side 303 of the pressing plate 30, the above-mentioned smoothing portion 40 has the shortest distance to the first side 303. For the convenience of description, the two ends of the smoothing portion 40 along the length direction are respectively recorded as the third end 402 and the fourth end 403, wherein the third end 402 is close to the first end 301 of the pressing plate 30, and the fourth end 403 is far away from the first end 301 of the pressing plate 30. From the third end 402 to the fourth end 403, the distance from the smoothing portion 40 to the first side 303 gradually shortens. At the fourth end 403, the distance from the smoothing portion 40 to the first side 303 reaches the shortest. The shortest distance from the smoothing portion 40 to the first side 303 is represented by d1. When the value of d1 is large, the distance from the fourth end 403 of the smoothing portion 40 to the first side 303 is far, and the moving trajectory of the smoothing portion 40 may not pass through the first end corner 203 of the tab 202, thereby failing to smooth the first end corner 203. When the value of d1 is small, the distance between the smoothing portion 40 and the first edge 303 is short, and the fourth end 403 of the smoothing portion 40 is easily bumped, thereby generating a sharp corner, which is easy to scratch the tab 202 during the lamination process, thereby affecting the quality of the battery cell.

[0058] In order to improve the above phenomenon, in one embodiment, d1 satisfies the following formula: 5mm≤d1≤8mm. Optionally, the value of d1 can be 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm or other values ​​that meet the above range, which are not listed one by one in this application. When the value of d1 meets the above range, the probability of the smoothing portion 40 passing through the first end angle 203 of the tab 202 can be increased, and the risk of the fourth end 403 of the smoothing portion 40 being bumped can also be reduced.

[0059] In addition to the first side 303, the pressing plate 30 also has a second side 304, and the second side 304 is located at the second end 302. Relative to the second side 304, the smoothing portion 40 also has the shortest distance to the second side 304, and is also at the fourth end 403. The shortest distance from the smoothing portion 40 to the second side 304 is represented by d2. When the value of d2 is large, the fourth end 403 of the smoothing portion 40 is far away from the second side 304, and the moving track of the orthographic projection of the smoothing portion 40 on the plane where the stacking table 10 is located may not completely cover the orthographic projection of the first end angle 203 on the plane where the stacking table 10 is located, thereby affecting the smoothing effect of the smoothing portion 40 on the first end angle 203. When the value of d2 is small, the fourth end 403 of the smoothing portion 40 is closer to the second edge 304. Before the pressing plate 30 is pulled out, at least part of the smoothing portion 40's orthographic projection on the plane where the stacking table 10 is located may be located within the orthographic projection of the material area 201 on the plane where the stacking table 10 is located. As a result, in the process of pulling out the pressing plate 30, the smoothing portion 40 will sweep across the surface of the material area 201, thereby causing a higher risk of the smoothing portion 40 scratching the material area 201.

[0060] In order to improve the above phenomenon, in one embodiment, d2 satisfies the following formula: 20mm≤d2≤30mm. Optionally, the value of d2 can be 22mm, 24mm, 26mm, 28mm or other values ​​that meet the above range, which are not listed one by one in this application. Within the above range, the smoothing portion 40 has an appropriate spacing from the second edge 304. Before the pressing plate 30 is pulled out, the flat area of ​​the pressing plate 30 where the smoothing portion 40 is not set can contact the material area 201, and the smoothing portion 40 can avoid the material area 201 and only contact the tab 202, thereby reducing the risk of the smoothing portion 40 scratching the material area 201 during the process of pulling out the pressing plate 30. At the same time, the moving trajectory of the orthographic projection of the smoothing portion 40 on the plane where the stacking table 10 is located can also completely cover the orthographic projection of the first end angle 203 on the plane where the stacking table 10 is located, thereby improving the smoothing effect of the smoothing portion 40 on the first end angle 203.

[0061] When the length of the smoothing portion 40 is specifically set, if the length of the smoothing portion 40 is long, it is easy to affect the stress distribution of the pressing plate 30, so that the pressing plate 30 is easy to break at the position corresponding to the smoothing portion 40. When the length of the smoothing portion 40 is short, the moving trajectory of the orthographic projection of the smoothing portion 40 on the plane where the stacking table 10 is located may not be able to completely cover the orthographic projection of the first end angle 203 on the plane where the stacking table 10 is located, thereby affecting the smoothing effect. In order to improve the above phenomenon, in one embodiment, the length of the smoothing portion 40 is represented by L1, and the length of the pole ear 202 along the extension direction of the first edge 204 is represented by L2, then L1 and L2 satisfy the following relationship: L2-2mm≤L1≤L2+2mm. In a specific embodiment, the value of L2 is 10mm, then 8mm≤L1≤12mm. Optionally, the value of L1 can be 9mm, 10mm, 11mm or other values ​​that meet the above range. Of course, L2 can also take other values, which are not listed one by one in this application.

[0062] When specifically setting the height of the smoothing portion 40 protruding from the surface of the pressing plate 30, if the height of the smoothing portion 40 protruding from the surface of the pressing plate 30 is large, it will hinder the lamination. If the height of the smoothing portion 40 protruding from the surface of the pressing plate 30 is small, it is not easy to smooth the tabs. In one embodiment, h1 represents the height of the smoothing portion 40 protruding from the surface of the pressing plate 30, and h2 represents the thickness of the pressing plate 30, and h1 and h2 satisfy the following formula: h2-2mm≤h1≤h2+2mm. In a specific embodiment, the value of h2 is 3mm, then 1mm≤h1≤5mm. Optionally, the value of h2 can be 1.5mm, 2mm, 2.5mm, 3mm or other values ​​that meet the above range. Of course, h2 can also take other values, which are not listed one by one in this application.

[0063] In another embodiment, h1 and h2 satisfy the following formula:

[0064] If the lamination table 10 is used as a reference, the smoothing portion 40 can be located on the side surface of the pressing plate 30 away from the lamination table 10, or on the side surface of the pressing plate 30 facing the lamination table 10. Alternatively, in one embodiment, the two surfaces of the pressing plate 30 that are away from each other in the thickness direction are respectively provided with the smoothing portion 40. In this way, when the pressing plate 30 is being pulled out, the smoothing portion 40 can smooth the pole ear 202 of a first pole piece 21 that is arranged on the same side and adjacent to it.

[0065] When the smoothing portion 40 and the pressing plate 30 are specifically connected, the smoothing portion 40 can be bonded to the surface of the pressing plate 30 , or the smoothing portion 40 can be welded to the surface of the pressing plate 30 , or the smoothing portion 40 can be an integral structure with the pressing plate 30 .

[0066] When the driving device 50 is specifically set, in one embodiment, the driving device 50 includes a screw. The screw includes components such as a nut and a screw, wherein the nut is connected to the pressing plate 30. The screw has a high transmission accuracy and can control the position of the pressing plate 30 more accurately. In other embodiments, the driving device 50 may also include a hydraulic cylinder or a pneumatic cylinder, and use hydraulic pressure or pneumatic pressure for transmission.

[0067] In addition to the above components, the lamination equipment also includes a diaphragm unwinding device, a positive electrode sheet feeding device, and a negative electrode sheet feeding device. The diaphragm unwinding device is used to unwind the diaphragm. During the lamination process, the diaphragm moves back and forth to form a Z-shaped fold. The positive electrode sheet feeding device and the negative electrode sheet feeding device are used to alternately place the positive electrode sheet and the negative electrode sheet on the diaphragm.

[0068] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.​

Claims

1. A lamination device, characterized in that: It includes a lamination table, a pressing plate and a driving device; The lamination platform is used to place pole pieces, and the pole pieces have a material area and a pole ear; and the pole pieces stacked on the lamination platform include a first pole piece, and the pole ear of the first pole piece has a first end angle; The pressing plate has a smoothing portion, and the smoothing portion protrudes from the surface of the pressing plate; The driving device is connected to the pressing plate, and is used to drive the pressing plate to be withdrawn from the bottom of the pole piece in a direction away from the lamination platform and pressed against the top of the pole piece; when the pressing plate is pressed against the top of the pole piece, the orthographic projection of the pressing plate on the plane where the lamination platform is located covers the orthographic projection of the first end angle on the plane where the lamination platform is located; The moving track of the orthographic projection of the smoothing portion on the plane where the laminating table is located covers the orthographic projection of the first end angle on the plane where the laminating table is located; when the first end angle is bent toward the side where the smoothing portion is located, the smoothing portion is used to smooth the first end angle; Two pressure plates are provided at one end corresponding to the pole ear of the first pole piece, and the two pressure plates are respectively a first pressure plate and a second pressure plate. The first pressure plate is located at the bottom of the first pole piece, and the second pressure plate is located at the top of the first pole piece. When the first pressure plate is pulled out from the bottom of the first pole piece, the second pressure plate presses the first pole piece.

2. The lamination device according to claim 1, characterized in that: The smoothing portion has a first surface, the first surface is convex in a direction away from the pressing plate, and the first surface is a curved surface.

3. The lamination device according to claim 2, characterized in that: The first surface extends along a first direction, and a cross section of the first surface perpendicular to the first direction is an elliptical arc, the eccentricity of the elliptical arc is e, and e satisfies the following formula: 0.5≤e≤0.8; The extending direction of the major axis of the elliptical arc is perpendicular to the surface of the pressing plate, and the extending direction of the minor axis of the elliptical arc is parallel to the surface of the pressing plate and perpendicular to the first direction.

4. The lamination device according to claim 1, characterized in that: The smoothing portion is a strip-shaped structure.

5. The lamination device according to claim 4, characterized in that: The pressing plate has a first end and a second end that are oppositely disposed and a first edge located between the first end and the second end, and the first end is connected to the driving device; When the pressing plate is pressed against the top of the pole piece, the orthographic projection of the first side on the plane where the lamination table is located intersects with the orthographic projection of the first pole piece on the plane where the lamination table is located, or the orthographic projection of the first side on the plane where the lamination table is located is located outside the orthographic projection of the pole piece on the plane where the lamination table is located; The smoothing portion is arranged obliquely, and along the direction from the first end to the second end, the distance from the smoothing portion to the first side gradually decreases.

6. The lamination device according to claim 5, characterized in that: The angle between the extension direction of the smoothing portion and the extension direction of the first side is , Satisfy the following formula: 50°≤ ≤60°.

7. The lamination device according to claim 5, characterized in that: The shortest distance from the smoothing portion to the first side is d1, and d1 satisfies the following formula: 5mm≤d1≤8mm.

8. The lamination device according to claim 5, characterized in that: The pressing plate also has a second edge, and the second edge is located at the second end; The shortest distance from the smoothing portion to the second side is d2, and d2 satisfies the following formula: 20 mm ≤ d2 ≤ 30 mm.

9. The lamination device according to any one of claims 1 to 8, characterized in that: When the pressing plate is pressed against the top of the pole piece, the smoothing portion is located on a side of a boundary between the material area and the pole ear of the first pole piece away from the material area of ​​the first pole piece.

10. The lamination device according to any one of claims 1 to 8, characterized in that: The maximum height of the smoothing portion protruding from the surface of the pressing plate is h1, the thickness of the pressing plate is h2, and h1 and h2 satisfy the following formula: |h1-h2|≤2mm.

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