Stacking apparatus

Abstract

The present invention relates to the technical field of batteries. Disclosed is a stacking apparatus. The stacking apparatus comprises a stacking platform, a pressing plate, and a driving device. The stacking platform is configured for having electrode sheets placed thereon, and the electrode sheets stacked on the stacking platform include a first electrode sheet, a tab of the first electrode sheet having a first corner; the pressing plate has a flattening portion, which protrudes from the surface of the pressing plate; and the driving device is connected to the pressing plate, and is used for driving the pressing plate to be drawn out from the bottom of an electrode sheet in a direction away from the stacking platform and to press against the top of the electrode sheet. When the pressing plate presses against the top of the electrode sheet, the orthographic projection of the pressing plate on the plane where the stacking platform is located covers the orthographic projection of the first corner on the plane where the stacking platform is located; and the movement trajectory of the orthographic projection of the flattening portion on the plane where the stacking platform is located covers the orthographic projection of the first corner on the plane where the stacking platform is located. When the first corner is bent toward a side where the flattening portion is located, the flattening portion can, during movement, push the first corner outward to unfold the first corner, such that the folding phenomenon of the tab is alleviated.

Description

A stacking device

[0001] This application claims priority to Chinese Patent Application No. 202411429377.9, filed on October 14, 2024, entitled "A Stacking Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and more particularly to a stacking device. Background Technology

[0003] In the manufacturing process of lithium-ion batteries, positive and negative electrode sheets are alternately stacked to form a semi-finished cell. Both the positive and negative electrode sheets include a current collector and an active material covering the surface of the current collector. The portion of the current collector not covered by the active material forms the tab. For the negative electrode, copper foil is typically used as the current collector. Because copper foil is relatively soft, the tab of the negative electrode is prone to warping at the corners. This can cause the tab to fold at the corners when the negative electrode is stacked into the cell, resulting in a higher proportion of cells with abnormal self-discharge and thus affecting the cell's yield. Summary of the Invention

[0004] This application provides a stacking device to solve the problem in the prior art that the negative electrode tabs are prone to folding at the corner positions, resulting in a high proportion of abnormal self-discharge in the manufactured cells.

[0005] This application provides a stacking apparatus, which includes a stacking stage, a pressure plate, and a driving device; wherein:

[0006] The stacking table is used to place electrode sheets, each electrode sheet having a material area and an electrode tab; and the electrode sheets stacked on the stacking table include a first electrode sheet, the electrode tab of the first electrode sheet having a first end angle;

[0007] The pressure plate has a smoothing portion that protrudes from the surface of the pressure plate;

[0008] The driving device is connected to the pressure plate and is used to drive the pressure plate to be pulled out from the bottom of the electrode sheet in a direction away from the stacking table and press against the top of the electrode sheet; when the pressure plate presses against the top of the electrode sheet, the orthographic projection of the pressure plate on the plane where the stacking table is located covers the orthographic projection of the first end corner on the plane where the stacking table is located; the movement trajectory of the smoothing part on the plane where the stacking table is located covers the orthographic projection of the first end corner on the plane where the stacking table is located; when the first end corner bends toward the side where the smoothing part is located, the smoothing part is used to smooth the first end corner.

[0009] The stacking equipment provided in this application has at least the following beneficial effects:

[0010] In the aforementioned lamination equipment, the pressure plate has a smoothing portion that protrudes from its surface, resulting in an uneven surface. During the platen's extraction, the smoothing portion moves with it. When the smoothing portion contacts the first corner of the electrode tab, it easily lifts the first corner, causing it to open outwards under its push. This improves the tab folding phenomenon during lamination, reducing the risk of self-discharge abnormalities in the resulting cells and increasing the cell yield. Attached Figure Description

[0011] Figure 1 is a schematic diagram of a stacking device provided in an embodiment of this application;

[0012] Figure 2 is a schematic diagram of a stacked sheet provided in an embodiment of this application;

[0013] Figure 3 is a schematic diagram of the pressure plate smoothing the first end corner according to an embodiment of this application;

[0014] Figure 4 is a schematic diagram showing the positional relationship between the orthographic projection of the pressure plate on the stacking table surface and the orthographic projection of the electrode sheet on the stacking table surface provided in the embodiment of this application.

[0015] Figure 5 is a schematic diagram showing another positional relationship between the orthographic projection of the pressure plate on the stacking table surface and the orthographic projection of the electrode sheet on the stacking table surface provided in the embodiment of this application.

[0016] Figure 6 is a schematic diagram of a pressure plate provided in an embodiment of this application;

[0017] Figure 7 is a schematic diagram of a cross-section of the first surface perpendicular to the first direction Y provided in an embodiment of this application;

[0018] Figure 8 is a schematic diagram of another structure of the pressure plate provided in the embodiment of this application.

[0019] Reference numerals: 10-Stacking stage; 20-Electrode; 201-Material area; 202-Electrode tab; 203-First end corner; 204-First edge; 21-First electrode; 22-Electrode a; 23-Electrode b; 24-Electrode c; 30-Pressure plate; 31-First pressure plate; 32-Second pressure plate; 301-First end; 302-Second end; 303-First side; 304-Second side; 40-Smoothing section; 401-First surface; 402-Third end; 403-Fourth end; 50-Drive device. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0021] Figure 1 is a schematic diagram of a stacking device provided in an embodiment of this application. As shown in Figure 1, in one embodiment, the stacking device includes a stacking table 10 for placing electrode sheets 20. The electrode sheet 20 includes a positive electrode and a negative electrode. During the stacking process, the positive and negative electrode sheets are alternately placed on the stacking table 10. The electrode sheet 20 has a material area 201 and an electrode tab 202. The material area 201 includes a current collector and an active material covering the surface of the current collector, while the electrode tab 202 only includes the current collector. For the positive and negative electrode sheets stacked on the stacking table 10, the orthographic projection of the material area 201 of the positive electrode sheet onto the plane of the stacking table 10 overlaps with the orthographic projection of the material area 201 of the negative electrode sheet onto the plane of the stacking table 10. The orthographic projections of the electrode tab 202 of the positive electrode sheet onto the plane of the stacking table 10 and the orthographic projections of the electrode tab 202 of the negative electrode sheet onto the plane of the stacking table 10 are respectively located at opposite ends of the aforementioned overlapping area.

[0022] Referring to Figure 1, the stacking apparatus also includes a pressure plate 30 and a driving device 50. The pressure plate 30 presses the electrode sheets 20 transferred to the stacking table 10, thereby reducing misalignment of the electrode sheets 20 during stacking and improving their alignment. The pressure plate 30 is connected to the driving device 50. Driven by the driving device 50, the pressure plate 30 can be pulled out from the bottom of the electrode sheet 20 in a direction away from the stacking table 10 and pressed against the top of the electrode sheet 20. The electrode sheet 20 is either a positive or negative electrode sheet that appears in the stacking sequence during the stacking process. In one embodiment, the electrode sheet 20 includes a positive electrode sheet and a negative electrode sheet. The stacking apparatus includes four pressure plates 30, two of which are located at the same end as the tabs 202 of the positive electrode sheet, and the other two pressure plates are located at the same end as the tabs 202 of the negative electrode sheet. During the stacking process, the two pressure plates 30 located at the same end as the tab 202 of the positive electrode alternately perform the above-mentioned actions, and the two pressure plates 30 located at the same end as the tab 202 of the negative electrode alternately perform the above-mentioned actions.

[0023] To clearly describe the action of the pressure plates 30 during the stacking process, two pressure plates 30 located at the same end are used as an example. Figure 2 is a schematic diagram of a stacking process provided by an embodiment of this application. As shown in Figure 2, the two pressure plates 30 are a first pressure plate 31 and a second pressure plate 32, respectively. At the first moment, the stacking stage 10 has an electrode a22, with the first pressure plate 31 located below the electrode a22 and the second pressure plate 32 located above the electrode a22. At the second moment, the stacking stage 10 has a newly placed electrode b23, with the polarity of electrode b23 opposite to that of electrode a22. Then, keeping the second pressure plate 32 stationary, the first pressure plate 31 is pulled out and pressed against the surface of electrode b23. At the third moment, the stacking stage 10 has a newly placed electrode c24, with the polarity of electrode c24 opposite to that of electrode b23. Then, keeping the first pressure plate 31 stationary, the second pressure plate 32 is pulled out and pressed against the surface of electrode c24. During the stacking process, the first pressure plate 31 and the second pressure plate 32 alternately perform the above actions, repeating the cycle.

[0024] Referring to Figures 1 and 2, the electrode sheets 20 stacked on the stacking stage 10 include a first electrode sheet 21, the tab 202 of which has a first end angle 203. The first electrode sheet 21 can be a positive electrode sheet or a negative electrode sheet. Before the pressure plate 30 is removed, the first electrode sheet 21 is in contact with the pressure plate 30. During the stacking process, the first electrode sheet 21 may be located above or below the pressure plate 30. When the pressure plate 30 presses against the top of the electrode sheet 20, the orthographic projection of the pressure plate 30 onto the plane of the stacking stage 10 overlaps the orthographic projection of the first end angle 203 onto the plane of the stacking stage 10.

[0025] The pressure plate 30 has a smoothing portion 40 that protrudes from the surface of the pressure plate 30. The first electrode 21 and the smoothing portion 40 are located on the same side of the pressure plate 30, and when the pressure plate 30 presses against the top of the electrode 20, the orthographic projection of the smoothing portion 40 onto the plane of the stacking table 10 and the orthographic projection of the tab 202 of the first electrode 21 onto the plane of the stacking table 10 at least partially overlap. Furthermore, during the removal of the pressure plate 30, the movement trajectory of the orthographic projection of the smoothing portion 40 onto the plane of the stacking table 10 can cover the orthographic projection of the first end corner 203 onto the plane of the stacking table 10. That is, the smoothing portion 40 can sweep over the first end corner 203. When the first end corner 203 folds towards the side where the smoothing portion 40 is located, the smoothing portion 40 can unfold the first end corner 203 during the movement, thereby smoothing the first end corner 203.

[0026] Figure 3 is a schematic diagram of the smoothing of the first end corner by the pressure plate according to an embodiment of this application. As shown in Figure 3, the arrow indicates the direction of withdrawal of the pressure plate 30. During the withdrawal of the pressure plate 30 in the above direction, the smoothing part 40 will move with the pressure plate 30 and sweep across the surface of the tab 202. When the smoothing part 40 contacts the first end corner 203 of the tab 202, the smoothing part 40 easily lifts the first end corner 203, causing the first end corner 203 to unfold outward under the push of the smoothing part 40, thereby extending. In this way, the folding phenomenon of the first end corner 203 during the stacking process is improved, reducing the risk of abnormal self-discharge of the cell and improving the yield of the cell.

[0027] To reduce the risk of the smoothing portion 40 scratching the material area 201 of the first electrode 21 and causing the active material in the material area 201 to fall off during the withdrawal of the pressure plate 30, in one embodiment, when the pressure plate 30 presses against the top of the electrode 20, the smoothing portion 40 is located on the side of the boundary between the material area 201 and the tab 202 of the first electrode 21 that is away from the material area 201 of the first electrode 21. That is, relative to the first electrode 21, the orthographic projection of the smoothing portion 40 on the plane of the stacking table 10 does not coincide with the orthographic projection of the material area 201 on the plane of the stacking table 10. In this way, the smoothing portion 40 will not come into contact with the material area 201 during the withdrawal of the pressure plate 30, thereby reducing the risk of the material area 201 being scratched by the smoothing portion 40.

[0028] When specifically setting the pressure plate 30, the pressure plate 30 should have high hardness, so that the pressure plate 30 is not easily deformed and can provide greater pressure to the electrode 20. The pressure plate 30 can be made of metal or non-metal, and this application does not limit it. The shape of the pressure plate 30 includes a variety of choices, for example, the pressure plate 30 can be rectangular, circular, elliptical or irregular in shape.

[0029] Figure 4 is a schematic diagram showing the positional relationship between the orthographic projection of the pressure plate on the stacking table surface and the orthographic projection of the electrode sheet on the stacking table surface provided in an embodiment of this application. Figure 5 is a schematic diagram showing another positional relationship between the orthographic projection of the pressure plate on the stacking table surface and the orthographic projection of the electrode sheet on the stacking table surface provided in an embodiment of this application. As shown in Figures 4 and 5, in some embodiments, the pressure plate 30 has a first end 301 and a second end 302 disposed opposite to each other, wherein the first end 301 is used to connect with the driving device 50. Before the pressure plate 30 is pulled out, the orthographic projection of the first end 301 on the plane where the stacking table 10 is located is located outside the orthographic projection of the electrode sheet 20 on the surface of the stacking table 10, and the orthographic projection of the second end 302 on the plane where the stacking table 10 is located and the orthographic projection of the electrode sheet 20 on the surface of the stacking table 10 at least partially overlap.

[0030] Optionally, for any electrode 20, the orthographic projection of the second end 302 on the surface of the stacking table 10 and the orthographic projection of the material area 201 of the electrode 20 on the surface of the stacking table 10 at least partially coincide. During the stacking process, when the pressure plate 30 presses against the surface of the negative electrode, the pressure plate 30 presses the material area 201 and the tab 202 of the negative electrode. When the pressure plate 30 presses against the surface of the positive electrode, the pressure plate 30 presses the material area 201 of the positive electrode. That is to say, the pressure plate 30 can press the electrode firmly, whether it is a positive or negative electrode.

[0031] Please continue referring to Figure 4. In addition to the first end 301 and the second end 302, the pressure plate 30 also has a first side 303, which is located between the first end 301 and the second end 302. Before the pressure plate 30 is removed, the orthographic projection of the first side 303 onto the plane of the stacking stage 10 intersects with the orthographic projection of the electrode 20 onto the plane of the stacking stage 10, or the orthographic projection of the first side 303 onto the plane of the stacking stage 10 is located outside the orthographic projection of the electrode 20 onto the plane of the stacking stage 10.

[0032] Specifically, the electrode 20 has a first edge 204, a portion of which is located in the material area 201, and another portion is located in the electrode tab 202. When the pressure plate 30 presses the electrode 20, the first edge 303 and the first edge 204 have various positional relationships. For example, as shown in FIG4, in one embodiment, the orthographic projection of the first edge 303 on the plane where the stacking table 10 is located coincides with 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 electrode 20 on the plane where the stacking table 10 is located.

[0033] As shown in Figure 5, in another embodiment, the orthographic projection of the first edge 303 onto the plane where the stacking stage 10 is located is outside the orthographic projection of the first edge 204 onto the plane where the stacking stage 10 is located. In this case, the orthographic projection of the first edge 303 onto the plane where the stacking stage 10 is located and the orthographic projection of the electrode 20 onto the plane where the stacking stage 10 is located do not intersect.

[0034] For electrode 20 where the tab 202 and the pressure plate 30 are located at the same end of the stacking table 10, in the above embodiment, the orthographic projection of the pressure plate 30 on the plane of the stacking table 10 can completely cover one end corner of the tab 202 of the electrode 20.

[0035] In another embodiment, the orthographic projection of the first edge 303 onto the plane where the stacking stage 10 is located is inside the orthographic projection of the first edge 204 onto the plane where the stacking stage 10 is located. In this case, the orthographic projection of the first edge 303 onto the plane where the stacking stage 10 is located intersects with the orthographic projection of the electrode 20 onto the plane where the stacking stage 10 is located.

[0036] When specifically setting the smoothing part 40, the smoothing part 40 includes various structural forms. Figure 6 is a schematic diagram of a pressure plate provided in an embodiment of this application. As shown in Figure 6, in one embodiment, the smoothing part 40 is a strip structure. The smoothing part 40 extends along a first direction Y, and the dimension of the smoothing part 40 along the first direction Y is larger than the dimension of the smoothing part 40 along a second direction, the second direction being perpendicular to the first direction Y.

[0037] Furthermore, 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.

[0038] In another embodiment, the smoothing portion 40 includes at least one convex hull. Optionally, the convex hull can be cylindrical, hemispherical, semi-ellipsoidal, or irregular in shape. The number of convex hulls can be one, two, three, or other numbers, and can be set according to actual needs in specific applications; this application does not limit this. In a specific embodiment, the smoothing portion 40 includes multiple convex hulls. When specifically arranging the multiple convex hulls, they can be arranged in a line along a set direction (such as the first direction Y), or they can be arranged in multiple rows, with adjacent rows aligned or staggered.

[0039] Of course, in addition to the above-mentioned structural forms, the smoothing part 40 may also include other structural forms, which will not be listed one by one in this application.

[0040] To reduce damage to the first electrode 21 caused by the smoothing portion 40 during the removal of the pressure plate 30, as shown in FIG6, in one embodiment, the smoothing portion 40 has a first surface 401 that protrudes away from the pressure plate 30 and is curved. Before the pressure plate 30 is removed, the first surface 401 faces and is in contact with the first electrode 21. During the removal of the pressure plate 30, because the first surface 401 is relatively smooth and has no sharp edges, the damage to the first electrode 21 caused by the smoothing portion 40 is reduced.

[0041] Please continue to refer to FIG. 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, which respectively extend along the first direction Y and are connected to the pressing plate 30. The part located between the two side edges bulges 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 cross-section can be an arc, an elliptical arc, or an irregular arc.

[0042] FIG. 7 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 application. As shown in FIG. 7, 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 more difficult it is to smooth 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 easier 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.

[0043] 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 will not list them one by one. Within the above range, the first surface 401 has a more suitable shape, so that the smoothing portion 40 has a better smoothing effect and reduces the scratching of the tab by the smoothing portion 40.

[0044] For the smoothing portion 40 with a strip structure, when specifically arranging the smoothing portion 40, relative to the first side 303 of the pressing plate 30, the smoothing portion 40 has various arrangement manners. As shown in FIG. 6, in one embodiment, the smoothing portion 40 is inclined relative to the first side 303. During the process of pulling out the pressing plate 30, the smoothing portion 40 moves parallel in a posture inclined relative to the first side 303 and sweeps across the surface of the tab 202.

[0045] FIG. 8 is another schematic diagram of the structure of the pressing plate provided by an embodiment of the present application. As shown in FIG. 8, in another embodiment, the smoothing portion 40 is perpendicular to the first side 303. During the process of pulling out the pressing plate 30, the smoothing portion 40 moves parallel in a posture perpendicular to the first side 303 and sweeps across the surface of the tab 202.

[0046] To reduce damage to the first corner 203 caused by the smoothing portion 40 during the smoothing process, as shown in FIG6, in one embodiment, the smoothing portion 40 is inclined relative to the first side 303, and the distance between the smoothing portion 40 and the first side 303 gradually decreases along the direction from the first end 301 to the second end 302. The inclined direction of the smoothing portion 40 is approximately the same as the inclined direction of the crease generated when the first corner 203 is bent. During the process of the smoothing portion 40 sweeping over the first corner 203, the smoothing portion 40 can contact the surface of the first corner 203, thereby pushing the first corner 203 outward and reducing the risk of damage to the edge of the first corner 203 due to tearing.

[0047] If θ 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 θ, the larger the area swept by the smoothing portion 40; the smaller the value of θ, the smaller the area swept by the smoothing portion 40. In one embodiment, θ satisfies the following formula: 50°≤θ≤60°, thereby making the area swept by the smoothing portion 40 larger, and also making the extension direction of the smoothing portion 40 and the tilt direction of the crease generated when the first end corner 203 is bent close to each other. Optionally, the value of θ 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.

[0048] The smoothing portion 40 has the shortest distance to the first edge 303 relative to the pressure plate 30. For ease of description, the two ends of the smoothing portion 40 along its length are designated as the third end 402 and the fourth end 403, respectively. The third end 402 is closer to the first end 301 of the pressure plate 30, and the fourth end 403 is farther away from the first end 301 of the pressure plate 30. From the third end 402 to the fourth end 403, the distance between the smoothing portion 40 and the first edge 303 gradually decreases. At the fourth end 403, the distance between the smoothing portion 40 and the first edge 303 reaches its shortest point. The shortest distance between the smoothing portion 40 and the first edge 303 is denoted by d1. When the value of d1 is large, the distance between the fourth end 403 of the smoothing portion 40 and the first edge 303 is large, and the movement trajectory of the smoothing portion 40 may not pass through the first end corner 203 of the tab 202, thus failing to smooth the first end corner 203. When the value of d1 is small, the distance between the smoothing part 40 and the first side 303 is relatively short. The fourth end 403 of the smoothing part 40 is easily bumped, resulting in a sharp corner. This sharp corner is likely to scratch the tab 202 during the stacking process, thus affecting the quality of the cell.

[0049] 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 satisfy the above range, which are not listed here. When the value of d1 satisfies the above range, the probability of the smoothing part 40 passing the first end angle 203 of the tab 202 can be increased, and the risk of the fourth end 403 of the smoothing part 40 being bumped can also be reduced.

[0050] In addition to the first side 303, the pressure plate 30 also has a second side 304, which is located at the second end 302. The smoothing part 40 also has a shortest distance to the second side 304 relative to it, and this shortest distance is also located at the fourth end 403. The shortest distance from the smoothing part 40 to the second side 304 is denoted by d2. When d2 is large, the distance between the fourth end 403 of the smoothing part 40 and the second side 304 is greater. The movement trajectory of the smoothing part 40's orthographic projection onto the plane of the stacking table 10 may not completely cover the orthographic projection of the first end corner 203 onto the plane of the stacking table 10, thus affecting the smoothing effect of the smoothing part 40 on the first end corner 203. When the value of d2 is small, the fourth end 403 of the smoothing part 40 is closer to the second side 304. Before the pressure plate 30 is pulled out, at least part of the smoothing part 40 may be projected onto the plane of the stacking table 10, which may be within the projection of the material area 201 onto the plane of the stacking table 10. This means that during the process of pulling out the pressure plate 30, the smoothing part 40 will sweep across the surface of the material area 201, which increases the risk of the smoothing part 40 scratching the material area 201.

[0051] 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 satisfy the above range, which will not be listed one by one in this application. Within the above range, the smoothing part 40 has a suitable distance from the second side 304. Before the pressure plate 30 is pulled out, the flat area of ​​the pressure plate 30 without the smoothing part 40 can contact the material area 201, while the smoothing part 40 can avoid the material area 201 and only contact the electrode tab 202, thereby reducing the risk of the smoothing part 40 scratching the material area 201 during the process of pulling out the pressure plate 30. At the same time, the movement trajectory of the smoothing part 40 in the plane of the stacking table 10 can also completely cover the orthographic projection of the first end corner 203 in the plane of the stacking table 10, thereby improving the smoothing effect of the smoothing part 40 on the first end corner 203.

[0052] When specifically setting the length of the smoothing part 40, if the smoothing part 40 is too long, it can easily affect the stress distribution of the pressure plate 30, making the pressure plate 30 prone to breakage at the position corresponding to the smoothing part 40. If the smoothing part 40 is too short, the movement trajectory of the orthographic projection of the smoothing part 40 onto the plane of the stacking table 10 may not completely cover the orthographic projection of the first end corner 203 onto the plane of the stacking table 10, thus affecting the smoothing effect. To improve the above phenomenon, in one embodiment, the length of the smoothing part 40 is represented by L1, and the length of the tab 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 satisfy the above range. Of course, L2 can also take other values, which are not listed one by one in this application.

[0053] When specifically setting the height of the smoothing portion 40 protruding from the surface of the pressure plate 30, if the height of the smoothing portion 40 protruding from the surface of the pressure plate 30 is large, it will hinder the stacking of the electrodes. If the height of the smoothing portion 40 protruding from the surface of the pressure plate 30 is small, it will be difficult to smooth the electrode tabs. In one embodiment, h1 represents the height of the smoothing portion 40 protruding from the surface of the pressure plate 30, and h2 represents the thickness of the pressure plate 30. 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 satisfy the above range. Of course, h2 can also take other values, which will not be listed one by one in this application.

[0054] In another embodiment, h1 and h2 satisfy the following formula: 0

[0055] ​Taking the stacking table 10 as a reference, the smoothing portion 40 can be located on the surface of the pressure plate 30 facing away from the stacking table 10, or on the surface of the pressure plate 30 facing the stacking table 10. Alternatively, in one embodiment, the smoothing portion 40 is provided on two surfaces of the pressure plate 30 that are opposite to each other along the thickness direction. In this way, during the removal of the pressure plate 30, the smoothing portion 40 can smooth the tab 202 of a first electrode 21 that is disposed on the same side and adjacent to it.

[0056] When specifically connecting the smoothing part 40 and the pressure plate 30, the smoothing part 40 is fixedly connected to the pressure plate 30. The smoothing part 40 can be bonded to the surface of the pressure plate 30, or the smoothing part 40 can be welded to the surface of the pressure plate 30, or the smoothing part 40 can be an integral structure with the pressure plate 30.

[0057] In one embodiment of the drive device 50, the drive device 50 includes a lead screw. The lead screw includes components such as a nut and a screw rod, wherein the nut is connected to the pressure plate 30. The lead screw has high transmission accuracy and can control the position of the pressure plate 30 relatively precisely. In other embodiments, the drive device 50 may also include a hydraulic cylinder or a pneumatic cylinder, using hydraulic or pneumatic pressure for transmission.

[0058] In addition to the components mentioned above, the lamination equipment also includes a diaphragm unwinding device, a positive electrode feeding device, and a negative electrode 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 feeding device and the negative electrode feeding device are used to alternately place the positive and negative electrode sheets onto the diaphragm.

[0059] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A stacking device, characterized in that, Includes a stacking table, pressure plate, and drive unit; The stacking table is used to place electrode sheets, each electrode sheet having a material area and an electrode tab; and the electrode sheets stacked on the stacking table include a first electrode sheet, the electrode tab of the first electrode sheet having a first end angle; The pressure plate has a smoothing portion that protrudes from the surface of the pressure plate; The driving device is connected to the pressure plate and is used to drive the pressure plate to be pulled out from the bottom of the electrode sheet in a direction away from the stacking table and press against the top of the electrode sheet; when the pressure plate presses against the top of the electrode sheet, the orthographic projection of the pressure plate on the plane where the stacking table is located covers the orthographic projection of the first end corner on the plane where the stacking table is located. The movement trajectory of the smoothing part's orthographic projection on the plane where the stacking table is located covers the orthographic projection of the first end corner on the plane where the stacking table is located; when the first end corner bends toward the side where the smoothing part is located, the smoothing part is used to smooth the first end corner.

2. The stacking equipment as described in claim 1, characterized in that, The smoothing portion has a first surface that protrudes in a direction away from the pressure plate and is curved.

3. The stacking equipment as described in claim 2, characterized in that, The first surface extends along a first direction, and the cross-section of the first surface perpendicular to the first direction is an elliptical arc, the eccentricity of the elliptical arc being e, which satisfies the following formula: 0.5≤e≤0.

8.

4. The stacking apparatus according to any one of claims 1-3, characterized in that, The smoothing section has a strip-shaped structure.

5. The stacking equipment as described in claim 4, characterized in that, The pressure plate has a first end and a second end disposed opposite to each other and a first side located between the first end and the second end, and the first end is connected to the driving device; When the pressure plate presses against the top of the electrode, the orthographic projection of the first edge on the plane where the stacking table is located intersects with the orthographic projection of the first electrode on the plane where the stacking table is located, or the orthographic projection of the first edge on the plane where the stacking table is located is located outside the orthographic projection of the electrode on the plane where the stacking table is located. The smoothing portion is inclined and the distance from the smoothing portion to the first side gradually decreases along the direction from the first end to the second end.

6. The stacking equipment as described in claim 5, characterized in that, The angle between the extension direction of the smoothing part and the extension direction of the first side is θ, and θ satisfies the following formula: 50°≤θ≤60°.

7. The stacking equipment as described in claim 5, characterized in that, The shortest distance from the smoothing part to the first side is d1, and d1 satisfies the following formula: 5mm≤d1≤8mm.

8. The stacking equipment as described in claim 5, characterized in that, The pressure plate also has a second side, which is located at the second end; The shortest distance from the smoothing part to the second side is d2, and d2 satisfies the following formula: 20mm≤d2≤30mm.

9. The stacking equipment according to claim 4, characterized in that, The smoothing portion extends along the first direction, and the dimension of the smoothing portion along the first direction is greater than the dimension of the smoothing portion along the second direction, which is perpendicular to the first direction.

10. The stacking apparatus according to any one of claims 1-3, characterized in that, The smoothing portion includes at least one convex bulge.

11. The stacking apparatus according to claim 10, characterized in that, The smoothing portion includes multiple convex bulges.

12. The stacking equipment according to claim 11, characterized in that, The plurality of the convex hulls are arranged in a line along the first direction.

13. The stacking equipment according to claim 11, characterized in that, The multiple convex hulls are configured as multiple rows.

14. The stacking apparatus according to claim 13, characterized in that, The convex hulls of two adjacent rows are aligned; or, the two adjacent rows are staggered.

15. The stacking apparatus according to any one of claims 1-13, characterized in that, When the pressure plate presses against the top of the electrode, the smoothing portion is located on the side of the boundary between the material area and the tab of the first electrode, away from the material area of ​​the first electrode.

16. The stacking apparatus according to any one of claims 1-13, characterized in that, The maximum height of the smoothing part protruding from the surface of the pressure plate is h1, and the thickness of the pressure plate is h2. h1 and h2 satisfy the following formula: |h1-h2|≤2mm.

17. The stacking apparatus according to any one of claims 1-13, characterized in that, The electrode includes a positive electrode and a negative electrode; The pressure plates are configured as four, two of which are located at the same end as the tab of the positive electrode, and the other two are located at the same end as the tab of the negative electrode.

18. The stacking apparatus according to any one of claims 1-13, characterized in that, The smoothing part is fixedly connected to the pressure plate.

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