Stacked battery cell, method for cutting a pole piece, and battery

Abstract

The present invention provides a stacked battery cell, a cutting method for a pole piece, and a battery. The stacked battery cell includes a pole piece and a separator stacked in sequence. The pole piece includes a positive pole piece and a negative pole piece, and the positive pole piece and the negative pole piece are stacked in sequence. A chamfered structure is provided at the corner of the pole piece. Among at least two adjacent pole pieces, at the same corner position, one pole piece is provided with a first chamfered structure, and the other pole piece is provided with a second chamfered structure. The size of the first chamfered structure is larger than that of the second chamfered structure, so that the second chamfered structure protrudes from the first chamfered structure. Since the second chamfered structure protrudes from the first chamfered structure, a hollowed-out area exists at the same corner position after the pole pieces are stacked. Subsequently, during the hot pressing process, the hollowed-out area can buffer and reduce the pressure, prevent the pressure from being transmitted layer by layer along with the pole pieces, and reduce the risk of burrs at the corners of the pole pieces piercing the separator during the hot pressing process.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly relates to a laminated battery cell, a method for cutting a pole piece, and a battery. Background Art

[0002] The battery cell is the basic structure of a battery, which is formed by sequentially arranging a positive electrode sheet 1', a separator 3', a negative electrode sheet 2', and a separator 3'. The processing techniques of the battery cell include laminating, winding, etc. As Figure 1 shown, in the process of laminating the battery cell, after the positive electrode sheet 1', the separator 3', the negative electrode sheet 2', and the separator 3' are reciprocally laminated, a battery cell structure is formed by thermal compounding.

[0003] Further, the positive electrode sheet 1' and the negative electrode sheet 2' are made by cutting a strip of material (such as hardware die cutting, laser cutting, etc.). After cutting, burrs will be formed at the four corner positions of the pole piece. In the subsequent lamination and hot pressing process, the pressure will cause the burrs to have the risk of piercing the separator. Especially the burrs on the positive electrode sheet 1' are more obvious, resulting in the scrapping of the battery due to short circuit. Since the battery cell structure usually adopts a negative-wrap-positive structure (the negative electrode sheet 2' is larger than and covers the positive electrode sheet 1'), especially at the four corner positions of the positive electrode sheet 1', as Figure 1 shown, in the thickness direction of the battery cell ( Figure 1 the inner dotted line direction shown), there are pole pieces (positive electrode sheet 1' and negative electrode sheet 2') on both sides of the separator 3'. This makes the pressure transfer layer by layer along with the pole pieces during the hot pressing process, making the corner burrs of the positive electrode sheet 1' easily pierce the separator. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the burrs at the corners of the pole piece have a great risk of piercing the separator during the hot pressing of the laminated battery cell in the prior art, so as to provide a laminated battery cell, a method for cutting a pole piece, and a battery.

[0005] To solve the above problems, the present invention provides a laminated battery cell, including sequentially laminated pole pieces and separators. The pole pieces include positive electrode sheets and negative electrode sheets, and the positive electrode sheets and the negative electrode sheets are sequentially laminated. A chamfered structure is provided at the corners of the pole pieces. Among at least two adjacent pole pieces, at the position of the same corner, one pole piece is provided with a first chamfered structure, and the other pole piece is provided with a second chamfered structure. Among them, the size of the first chamfered structure is larger than that of the second chamfered structure, so that the second chamfered structure protrudes from the first chamfered structure.

[0006] Optionally, among at least two adjacent pole pieces of the same polarity, at the position of the same corner, one pole piece is provided with a first chamfered structure, and the other pole piece is provided with a second chamfered structure.

[0007] Optionally, among at least two adjacent positive electrode plates, at the same corner position, one positive electrode plate is provided with a first cut-off corner structure, and the other positive electrode plate is provided with a second cut-off corner structure.

[0008] Optionally, among at least two adjacent negative electrode plates, at the same corner position, one negative electrode plate is provided with a first cut-off corner structure, and the other negative electrode plate is provided with a second cut-off corner structure.

[0009] Optionally, the electrode plates of the same polarity include a first electrode plate and a second electrode plate. Among the four corners of the first electrode plate and the second electrode plate, at any corner position, the first electrode plate is provided with one of the first cut-off corner structure and the second cut-off corner structure, and the second electrode plate is provided with the other of the first cut-off corner structure and the second cut-off corner structure.

[0010] Optionally, both the first electrode plate and the second electrode plate include a first top corner, a second top corner, a first bottom corner, and a second bottom corner. The first bottom corner and the first top corner are on the same side, and the second bottom corner and the second top corner are on the same side, where: the first top corner includes the first cut-off corner structure or the second cut-off corner structure; and / or, the second top corner includes the first cut-off corner structure or the second cut-off corner structure; and / or, the first bottom corner includes the first cut-off corner structure or the second cut-off corner structure; and / or, the second bottom corner includes the first cut-off corner structure or the second cut-off corner structure.

[0011] Optionally, the first top corner and the second bottom corner of the first electrode plate include the first cut-off corner structure, and the second top corner and the first bottom corner of the first electrode plate include the second cut-off corner structure; the second top corner and the first bottom corner of the second electrode plate include the first cut-off corner structure, and the first top corner and the second bottom corner of the second electrode plate include the second cut-off corner structure.

[0012] Optionally, the first top corner and the second top corner of the first electrode plate include the first cut-off corner structure, and the first bottom corner and the second bottom corner of the first electrode plate include the second cut-off corner structure; the first bottom corner and the second bottom corner of the second electrode plate include the first cut-off corner structure, and the first top corner and the second top corner of the second electrode plate include the second cut-off corner structure.

[0013] Optionally, the first top corner and the first bottom corner of the first electrode plate include the first cut-off corner structure, and the second top corner and the second bottom corner of the first electrode plate include the second cut-off corner structure; the second top corner and the second bottom corner of the second electrode plate include the first cut-off corner structure, and the first top corner and the first bottom corner of the second electrode plate include the second cut-off corner structure.

[0014] Optionally, the first top corner, the second top corner, the first bottom corner, and the second bottom corner of the first electrode plate all include the first cut-off corner structure; the first top corner, the second top corner, the first bottom corner, and the second bottom corner of the second electrode plate all include the second cut-off corner structure.

[0015] Optionally, the negative electrode plate is larger than the positive electrode plate, and the outer contour of the negative electrode plate protrudes beyond the outer contour of the positive electrode plate.

[0016] Optionally, the chamfered structure includes rounded corners. The size of the first chamfered structure is in the range of 1 mm to 5 mm, the size of the second chamfered structure is in the range of 0.2 mm to 2 mm, the size of the burrs generated after cutting the first chamfered structure is in the range of 5 μm - 15 μm, and the size of the burrs generated after cutting the second chamfered structure is in the range of 5 μm - 20 μm.

[0017] Optionally, the chamfered structure is formed by die cutting with hardware or laser cutting.

[0018] The present invention also provides a method for cutting pole pieces, which is used to cut the pole pieces of the above-mentioned stacked battery cells, cut adjacent pole pieces, and cut two top corners and two bottom corners on the opposite sides of adjacent pole pieces. The method for cutting pole pieces includes: Step S1: The cutting mechanism cuts a first trajectory along the first direction of the width of the strip. The first trajectory cuts one top corner and one bottom corner, and cuts adjacent pole pieces; Step S2: The cutting mechanism cuts a second trajectory along the second direction of the width of the strip. The second trajectory cuts the other top corner and the other bottom corner, wherein the first direction and the second direction are opposite.

[0019] Optionally, the first trajectory includes a first arc segment, a first straight segment, and a second arc segment connected in sequence along the direction from the starting point to the ending point. The second trajectory includes a third arc segment and a fourth arc segment spaced apart along the direction from the starting point to the ending point.

[0020] Optionally, the ending point of the third arc segment is connected to the ending point of the first straight segment, and the starting point of the fourth arc segment is connected to the starting point of the first straight segment; or, the third arc segment passes through the ending point of the first straight segment, and the intersection point is located between the starting point and the ending point of the third arc segment, the fourth arc segment passes through the starting point of the first straight segment, and the intersection point is located between the starting point and the ending point of the fourth arc segment.

[0021] Optionally, the second trajectory further includes a second straight segment, which is connected between the third arc segment and the fourth arc segment, and the second straight segment coincides with or is offset from the first straight segment.

[0022] Optionally, the bending directions of the first arc segment and the second arc segment are opposite, and the first arc segment and the second arc segment are used to cut the top corner of one pole piece and the bottom corner of another pole piece among adjacent pole pieces; the bending directions of the third arc segment and the fourth arc segment are opposite, and the third arc segment and the fourth arc segment are used to cut the bottom corner of one pole piece and the top corner of another pole piece among adjacent pole pieces.

[0023] Optionally, the bending directions of the first arc segment and the second arc segment are the same, and the first arc segment and the second arc segment are used to cut the top angle and the bottom angle of one of the adjacent pole pieces; the bending directions of the third arc segment and the fourth arc segment are the same, and the third arc segment and the fourth arc segment are used to cut the bottom angle and the top angle of the other pole piece among the adjacent pole pieces.

[0024] Optionally, the types of the cut corner structures cut by the first arc segment, the second arc segment, the third arc segment, and the fourth arc segment are the same, and the types of the cut corner structures include a first cut corner structure and a second cut corner structure.

[0025] Optionally, the first arc segment and the second arc segment are suitable for cutting the first cut corner structure, and the third arc segment and the fourth arc segment are suitable for cutting the second cut corner structure.

[0026] Optionally, the types of the cut corner structures cut by the first arc segment and the fourth arc segment are the same, the types of the cut corner structures cut by the second arc segment and the third arc segment are the same, and the types of the cut corner structures cut by the first arc segment and the second arc segment are different, wherein the types of the cut corner structures include a first cut corner structure and a second cut corner structure.

[0027] Optionally, the types of the cut corner structures cut by the first arc segment and the third arc segment are the same, the types of the cut corner structures cut by the second arc segment and the fourth arc segment are the same, and the types of the cut corners cut by the first arc segment and the second arc segment are different, wherein the types of the cut corner structures include a first cut corner structure and a second cut corner structure.

[0028] Optionally, a cutting slit is provided on the cutting table, and the adjacent pole pieces are cut off at the cutting slit. Wherein, an arc structure is provided at the edge of the cutting slit, and an adsorption mechanism and a dust removal mechanism are provided below the cutting slit.

[0029] Optionally, the pole piece cutting method further includes: Step S3: After repeatedly executing Step S1 and Step S2 and cutting a preset number of first pole pieces, change the types of the cutting chamfers of the first arc segment, the second arc segment, the third arc segment, and the fourth arc segment to obtain a third track segment and a fourth track segment; Step S4: The cutting mechanism cuts the third track along the third direction of the width of the strip, the third track cuts one of the top angles and one of the bottom angles, and cuts off the adjacent pole pieces; Step S5: The cutting mechanism cuts the fourth track along the fourth direction of the width of the strip, and the fourth track cuts the other top angle and the other bottom angle; Step S6: Repeatedly execute Step S4 and Step S5 and cut a preset number of second pole pieces, wherein the change of the types of the cutting chamfers includes changing the first cut corner structure to the second cut corner structure, or changing the second cut corner structure to the first cut corner structure, the third direction and the fourth direction are opposite, the third direction is the same as the first direction, or the third direction is the same as the second direction.

[0030] Optionally, step S4 is performed before step S5, or step S5 is performed before step S4.

[0031] The present invention also provides a battery, including a housing and a stacked cell disposed in the housing, and the stacked cell is the above-mentioned stacked cell.

[0032] The present invention has the following advantages:

[0033] By using the technical solution of the present invention, by setting the same corner position of adjacent electrode plates to different sizes, that is, one of the electrode plates is provided with a first cut-off corner structure, and the other electrode plate is provided with a second cut-off corner structure, when the electrode plate and the separator are stacked, in the thickness direction of the cell, the second cut-off corner structure protrudes from the first cut-off corner structure, and there is a void area at the same corner position. Subsequently, during the hot pressing process, the void area can buffer and reduce the pressure, prevent the pressure from being transmitted layer by layer along the electrode plate, and reduce the risk of burrs at the corners of the electrode plate piercing the separator during the hot pressing process. Therefore, the technical solution of the present invention solves the defect that there is a large risk of burrs at the corners of the electrode plate piercing the separator during the hot pressing of the stacked cell in the prior art. Description of the Drawings

[0034] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 Shows a cross-sectional view of a stacked cell in the prior art at the corners of the electrode plate;

[0036] Figure 2 Shows a schematic structural diagram of the first electrode plate and the second electrode plate of the positive electrode plate of the first embodiment of the stacked cell of the present invention;

[0037] Figure 3 Shows Figure 2 The schematic structural diagram after the first electrode plate and the second electrode plate are stacked in;

[0038] Figure 4 Shows Figure 3 The enlarged schematic diagram at A in;

[0039] Figure 5 Shows a schematic structural diagram of the first electrode plate and the second electrode plate of the negative electrode plate of the first embodiment of the stacked cell of the present invention;

[0040] Figure 6 Shows Figure 5Schematic diagram of the structure after the first and second electrode plates are stacked;

[0041] Figure 7 Shows Figure 6 Enlarged schematic diagram at position B in;

[0042] Figure 8 Schematic diagram of the structure of the first embodiment of the stacked battery cell of the invention;

[0043] Figure 9 Shows Figure 8 Cross-sectional schematic diagram taken along the C-C direction in;

[0044] Figure 10 Schematic diagram of the structure of the first and second electrode plates of the second embodiment of the stacked battery cell of the invention;

[0045] Figure 11 Schematic diagram of the structure of the first and second electrode plates of the third embodiment of the stacked battery cell of the invention;

[0046] Figure 12 Schematic diagram of the structure of the first and second electrode plates of the fourth embodiment of the stacked battery cell of the invention;

[0047] Figure 13 Schematic diagram of the first cutting trajectory of the first embodiment of the electrode plate cutting method of the invention;

[0048] Figure 14 Schematic diagram of the second cutting trajectory of the first embodiment of the electrode plate cutting method of the invention;

[0049] Figure 15 Shows Figure 13 Schematic diagram of the equipment when cutting the first trajectory in;

[0050] Figure 16 Shows Figure 14 Schematic diagram of the equipment when cutting the second trajectory in;

[0051] Figure 17 Shows Figure 13 The first trajectory in and Figure 14 Composite schematic diagram of the second trajectory in;

[0052] Figure 18 Shows the composite schematic diagram of the third and fourth trajectories obtained by transforming the first and second trajectories through Figure 17 in;

[0053] Figure 19 Shows the composite schematic diagram of the third and fourth trajectories obtained by transforming the first and second trajectories, and Figure 17 in; Figure 18 Schematic diagram of cutting the first and second electrode plates by the third and fourth trajectories in;

[0054] Figure 20 Schematic diagram showing the first cutting trajectory of the second embodiment of the pole piece cutting method of the present invention;

[0055] Figure 21 Schematic diagram showing the second cutting trajectory of the second embodiment of the pole piece cutting method of the present invention;

[0056] Figure 22 Shows Figure 20 The first trajectory in Figure 21 And the composite schematic diagram of the second trajectory in

[0057] Figure 23 Shows by Figure 22 The composite schematic diagram of the third trajectory and the fourth trajectory obtained by transforming the first trajectory and the second trajectory in

[0058] Figure 24 Schematic diagram showing the first cutting trajectory of the third embodiment of the pole piece cutting method of the present invention;

[0059] Figure 25 Schematic diagram showing the second cutting trajectory of the third embodiment of the pole piece cutting method of the present invention;

[0060] Figure 26 Shows Figure 24 The first trajectory in Figure 25 And the composite schematic diagram of the second trajectory in

[0061] Figure 27 Shows by Figure 26 The composite schematic diagram of the third trajectory and the fourth trajectory obtained by transforming the first trajectory and the second trajectory in

[0062] Figure 28 Schematic diagram showing the first cutting trajectory of the fourth embodiment of the pole piece cutting method of the present invention;

[0063] Figure 29 Schematic diagram showing the second cutting trajectory of the fourth embodiment of the pole piece cutting method of the present invention;

[0064] Figure 30 Shows Figure 28 The first trajectory in Figure 29 And the composite schematic diagram of the second trajectory in

[0065] Figure 31 Shows by Figure 30 The composite schematic diagram of the third trajectory and the fourth trajectory obtained by transforming the first trajectory and the second trajectory in

[0066] Figure 32 Shows Figure 30Schematic diagram of another cutting method for the first and second trajectories;

[0067] Figure 33 Shows Figure 29 Schematic diagram of another cutting method for the second trajectory in;

[0068] Figure 34 Shows based on Figure 33 In the form of the second trajectory, schematic diagram of the first cutting form of the first and second trajectories;

[0069] Figure 35 Shows based on Figure 33 In the form of the second trajectory, schematic diagram of the second cutting form of the first and second trajectories;

[0070] Figure 36 Schematic diagram of cutting the first trajectory in the fifth embodiment of the pole piece cutting method of the present invention;

[0071] Figure 37 Schematic diagram of cutting the second trajectory in the sixth embodiment of the pole piece cutting method of the present invention;

[0072] Figure 38 Shows Figure 36 In the first trajectory and Figure 37 Composite schematic diagram of the second trajectory in;

[0073] Figure 39 Shows by Figure 38 Composite schematic diagram of the third and fourth trajectories obtained by transforming the first and second trajectories in;

[0074] Figure 40 Schematic diagram of burrs under an electron microscope after cutting the first and second corner - missing structures.

[0075] Explanation of reference numerals:

[0076] 1', positive electrode sheet; 2', negative electrode sheet; 3', separator;

[0077] 1, pole piece; 11, positive electrode sheet; 12, negative electrode sheet; 13, first pole piece; 14, second pole piece; 101, first apex angle; 102, second apex angle; 103, first base angle; 104, second base angle; 2, separator; 3, corner - missing structure; R, first corner - missing structure; r, second corner - missing structure;

[0078] 100, first trajectory; 110, first arc segment; 120, first straight - line segment; 130, second arc segment; 200, second trajectory; 210, third arc segment; 220, fourth arc segment; 230, second straight - line segment; 300, third trajectory; 400, fourth trajectory. Detailed implementation manners

[0079] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0080] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0081] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0082] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0083] The battery cell is the basic structure of the battery, which is formed by sequentially arranging a positive electrode sheet 1', a separator 3', a negative electrode sheet 2', and a separator 3'. The processing techniques of the battery cell include lamination, winding, etc. As Figure 1 shown, in the lamination process of the battery cell, the positive electrode sheet 1', the separator 3', the negative electrode sheet 2', and the separator 3' are repeatedly laminated to form a battery cell structure.

[0084] Furthermore, the positive electrode sheet 1' and the negative electrode sheet 2' are made by cutting a strip of material (such as metal die cutting, laser cutting, etc.). After cutting, burrs will be formed at the four corner positions of the electrode sheet. During the hot pressing process after lamination, the pressure will cause the burrs to have the risk of piercing the separator and lead to the scrapping of the battery due to short circuit. Since the battery cell structure usually adopts a negative-wrap-positive structure (the negative electrode sheet 2' is larger than and covers the positive electrode sheet 1'), especially at the four corner positions of the positive electrode sheet 1', as Figure 1 shown, in the thickness direction of the battery cell ( Figure 1In the direction of the inner dashed line shown), there are electrode plates (the positive electrode plate 1' and the negative electrode plate 2') on both sides of the separator 3'. This makes it possible that during the hot pressing process, the pressure is transmitted layer by layer along with the electrode plates, and the burrs at the corners of the positive electrode plate 1' are very likely to pierce the separator.

[0085] To solve the above problems, the present application provides a stacked battery cell and a method for cutting an electrode plate for processing the electrode plate in the stacked battery cell. The following will introduce these two aspects in detail.

[0086] I. Stacked battery cell

[0087] Embodiment 1

[0088] As Figures 2 to 9 shown, Embodiment 1 of the stacked battery cell according to the present application includes an electrode plate 1 and a separator 2 stacked in sequence. Among them, the electrode plate 1 includes a positive electrode plate 11 and a negative electrode plate 12, and the positive electrode plate 11 and the negative electrode plate 12 are stacked in sequence.

[0089] Furthermore, a cut - off corner structure 3 is provided at the corner of the electrode plate 1. The cut - off corner structure 3 includes a chamfer, a fillet or other forms of cut - off corner structures. Among at least two adjacent electrode plates 1, at the same corner position, one electrode plate 1 is provided with a first cut - off corner structure R, and the other electrode plate 1 is provided with a second cut - off corner structure r. And the size of the first cut - off corner structure R is larger than the size of the second cut - off corner structure r, so that the second cut - off corner structure r protrudes from the first cut - off corner structure R.

[0090] Using the technical solution of this embodiment, by setting different sizes at the same corner position of adjacent electrode plates 1, that is, one electrode plate 1 is provided with a first cut - off corner structure R and the other electrode plate is provided with a second cut - off corner structure r. When the electrode plate 1 and the separator 2 are stacked, in the thickness direction of the battery cell, the second cut - off corner structure r protrudes from the first cut - off corner structure R, and there is a void area at the same corner position. Subsequently, during the hot pressing process, the void area can buffer and reduce the pressure, prevent the pressure from being transmitted layer by layer along with the electrode plate 1, and reduce the risk that the burrs at the corners of the electrode plate 1 pierce the separator during the hot pressing process. Therefore, the technical solution of this embodiment solves the defect that in the prior art, when the stacked battery cell is hot - pressed, there is a relatively high risk that the burrs at the corners of the electrode plate pierce the separator.

[0091] First of all, it should be noted that the electrode plate 1 in this embodiment includes a positive electrode plate 11 and a negative electrode plate 12, and the stacked battery cell is formed by sequentially and repeatedly stacking the positive electrode plate 11, the separator 2 and the negative electrode plate 12. The structural form of the stacked battery cell is "... separator - negative electrode plate - separator - positive electrode plate - separator - negative electrode plate - separator...".

[0092] As Figure 2As shown, the pole piece 1 is a block structure, and the pole piece 1 is formed by cutting on a material strip. After the pole piece 1 is cut, if its four corners are not processed, it will be a right-angle structure. The right-angle structure is relatively sharp, and there is a greater risk of piercing the diaphragm 2 during the subsequent thermal composite process. Therefore, in this embodiment, it is necessary to process the corners of the pole piece 1 with a notched structure 3.

[0093] It should be noted that Figure 2 The pole piece 1 is explained in the direction shown, and the corners of the pole piece 1 refer to the positions where the top edge and the side edge meet, and the positions where the bottom edge and the side edge meet. Therefore, the pole piece 1 has four corner positions.

[0094] The "missing corner structure 3" in this embodiment refers to cutting off a portion of the material at the corners of the pole piece 1 so that the boundary line at the corners of the pole piece 1 becomes smoother. The missing corner structure 3 can be a chamfer cut by a straight edge, a rounded corner cut by an arc edge, or an irregular missing corner. When the missing corner structure 3 is an irregular missing corner, its cutting trajectory can be an irregular arc, a combination of multiple straight lines, a combination of straight lines and (regular or irregular) arcs, and so on. Therefore, as long as the corners of the pole piece 1 are cut to obtain a smoother structure, it is included in the meaning of the "missing corner structure 3" in this embodiment.

[0095] Optionally, the corner-cut structure 3 of the pole piece 1 can be processed together with the pole piece 1 when it is cut, or can be processed after the pole piece 1 is cut.

[0096] Further, in this embodiment, the notched corner structure 3 includes a first notched corner structure R and a second notched corner structure r, and the size of the first notched corner structure R is larger than the size of the second notched corner structure r. Wherein, "the size of the first notched corner structure R is larger than the size of the second notched corner structure r" means that more material needs to be cut when processing the first notched corner structure R than when processing the second notched corner structure r.

[0097] For example, when the notch structure 3 is chamfered, C4*45° (the first notch structure R) is greater than C2*45° (the second notch structure r).

[0098] For another example, when the corner-cut structure 3 is rounded, R24 (the first corner-cut structure R) is greater than R12 (the second corner-cut structure r).

[0099] like Figure 3 and Figure 4 As shown, those skilled in the art can understand that since the material required to be cut for processing the first notched corner structure R is more than the material required to be cut for processing the second notched corner structure r, in the two pole pieces 1, at the same corner position, if one of the pole pieces 1 is provided with the first chamfer structure R and the other pole piece 1 is provided with the second chamfer structure r, then after the two pole pieces 1 are stacked and the edges are aligned, the second notched corner structure r should protrude from the first notched corner structure R at the corner.

[0100] Therefore, in the technical solution of this embodiment, among adjacent electrode tabs 1 of the stacked battery cell, at the same corner, one electrode tab 1 is provided with a first cutout structure R, and the other electrode tab is provided with a second cutout structure r. As Figure 8 and Figure 9 shown, at the corner position of the electrode tab 1 of the stacked battery cell, the part where the second cutout structure r protrudes from the first cutout structure R forms a hollowed-out area. During the subsequent hot pressing process, the hollowed-out area can buffer and reduce the pressure, thereby reducing the risk of burrs piercing the separator.

[0101] It should be noted that the "adjacent electrode tabs 1" may include adjacent positive electrode tabs 11, may include adjacent negative electrode tabs 12, or may include adjacent positive electrode tabs 11 and negative electrode tabs 12.

[0102] Furthermore, the "adjacent electrode tabs 1" may be every two adjacent electrode tabs 1 in the stacked battery cell, including every two adjacent positive electrode tabs 11, every two adjacent negative electrode tabs 12, and every two adjacent positive electrode tabs 11 and negative electrode tabs 12.

[0103] Furthermore, the "adjacent electrode tabs 1" may also be only some adjacent electrode tabs 1 in the stacked battery cell, including at least two adjacent positive electrode tabs 11, at least two adjacent negative electrode tabs 12, and at least two adjacent positive electrode tabs 11 and negative electrode tabs 12.

[0104] In this embodiment, the stacked battery cell adopts the industry's traditional "negative wrapping positive" structure, that is, the negative electrode tab 12 is larger than the positive electrode tab 11, and the outer contour of the negative electrode tab 12 protrudes from the outer contour of the positive electrode tab 11. As recorded in the above background art and combined with Figure 8 and Figure 9 shown, the corner positions of adjacent negative electrode tabs 12 have been separated by the positive electrode tab 11 to form a hollowed-out area. However, the positions where the corners of the positive electrode tab 11 are located are prone to the pressure continuously transmitted by the electrode tabs. Therefore, in this embodiment, preferably, among at least two adjacent positive electrode tabs 11, at the same corner position, one positive electrode tab 11 is provided with a first cutout structure R, and the other positive electrode tab 11 is provided with a second cutout structure r.

[0105] Combined with Figure 9 shown, with such a setting, a hollowed-out area where the second cutout structure r protrudes from the first cutout structure R is generated at the same corner of the positive electrode tab 11 of the stacked battery cell. Therefore, during the subsequent hot pressing process, the hollowed-out area can buffer and reduce the pressure, thereby greatly reducing the risk of burrs piercing the separator during the hot pressing process at the positive electrode tab 11.

[0106] Preferably, at the same corner, the cut-off structures 3 of each adjacent positive electrode plate 11 are different. That is, at the same corner, the corner form of the positive electrode plate 11 is "… the first cut-off structure R - the second cut-off structure r - the first cut-off structure R - the second cut-off structure r…".

[0107] As Figures 4 to 7 shown, further, in at least two adjacent negative electrode plates 12 of this embodiment, at the position of the same corner, one of the negative electrode plates 12 is provided with the first cut-off structure R, and the other negative electrode plate 12 is provided with the second cut-off structure r.

[0108] As Figure 9 shown, since the size of the negative electrode plate 12 is larger than that of the positive electrode plate 11, after stacking, the first cut-off structure R of the negative electrode plate 12 still protrudes from the second cut-off structure r of the positive electrode plate 11. With such a setting, as Figure 9 shown, at the corner of the laminated battery cell of the electrode plate 1, a stepped structure in a sawtooth form is formed, increasing the number of void areas, thereby greatly reducing the risk that burrs pierce the separator 2 during the hot pressing process of the laminated battery cell.

[0109] Preferably, at the same corner, the cut-off structures 3 of each adjacent negative electrode plate 12 are different. That is, at the same corner, the corner form of the negative electrode plate 12 is "… the first cut-off structure R - the second cut-off structure r - the first cut-off structure R - the second cut-off structure r…".

[0110] As described above, since the electrode plate 1 has four corner positions, for the adjacent positive electrode plate 11 and negative electrode plate 12, "one of the electrode plates 1 is provided with the first cut-off structure R, and the other electrode plate 1 is provided with the second cut-off structure r" can be satisfied at one corner, "one of the electrode plates 1 is provided with the first cut-off structure R, and the other electrode plate 1 is provided with the second cut-off structure r" can be satisfied at two corners, "one of the electrode plates 1 is provided with the first cut-off structure R, and the other electrode plate 1 is provided with the second cut-off structure r" can be satisfied at three corners, or "one of the electrode plates 1 is provided with the first cut-off structure R, and the other electrode plate 1 is provided with the second cut-off structure r" can be satisfied at all four corners.

[0111] Preferably, at all four corners of the adjacent positive electrode plates 11 of this embodiment, "one of the electrode plates 1 is provided with the first cut-off structure R, and the other electrode plate 1 is provided with the second cut-off structure r" is satisfied, and at all four corners of the adjacent negative electrode plates 12 of this embodiment, "one of the electrode plates 1 is provided with the first cut-off structure R, and the other electrode plate 1 is provided with the second cut-off structure r" is also satisfied.

[0112] In an embodiment (not shown), if the positive electrode sheet 11 and the negative electrode sheet 12 have the same size (only the positions where the tabs are provided are different), then in adjacent positive electrode sheets 11 and negative electrode sheets 12, it can be set to meet the condition of "in the same corner, one of the electrode sheets 1 is provided with a first cut-off corner structure R, and the other electrode sheet 1 is provided with a second cut-off corner structure r".

[0113] The above has introduced the setting method of the cut-off corner structure 3 from the overall positive electrode sheet 11 and negative electrode sheet 12 of the stacked battery cell. The following will further introduce the setting methods of the single positive electrode sheet 11 and negative electrode sheet 12 in detail.

[0114] As Figure 2 and Figure 5 shown, in the technical solution of this embodiment, the electrode sheets 1 of the same polarity include a first electrode sheet 13 and a second electrode sheet 14. Among the four corners of the first electrode sheet 13 and the second electrode sheet 14, at any corner position, the first electrode sheet 13 is provided with one of the first cut-off corner structure R and the second cut-off corner structure r, and the second electrode sheet 14 is provided with the other of the first cut-off corner structure R and the second cut-off corner structure r.

[0115] Specifically, the electrode sheets 1 of the same polarity include a positive electrode sheet 11 and a negative electrode sheet 12, that is, the positive electrode sheet 11 includes a first electrode sheet 13 and a second electrode sheet 14, and the negative electrode sheet 12 includes a first electrode sheet 13 and a second electrode sheet. Those skilled in the art can understand that the positive electrode sheet 11 includes two specifications of electrode sheet forms (AB sheet forms), and the negative electrode sheet 12 also includes two specifications of electrode sheet forms (AB sheet forms).

[0116] First, taking the positive electrode sheet 11 as an example, as Figures 2 to 4 shown, in the stacked battery cell, the positive electrode sheet 11 is stacked in the form of "…… first electrode sheet 13 - second electrode sheet 14 - first electrode sheet 13 - second electrode sheet 14 ……". Since the positive electrode sheet 11 satisfies that at all four corners, one of the positive electrode sheets 11 is provided with a first cut-off corner structure R, and the other positive electrode sheet 11 is provided with a second cut-off corner structure r, that is, among the first electrode sheet 13 and the second electrode sheet 14, at any corner position, one is provided with a first cut-off corner structure R, and the other is provided with a second cut-off corner structure r.

[0117] This enables various combination methods for the corner forms of the first electrode sheet 13 and the second electrode sheet 14. Specifically:

[0118] As Figure 2 shown, both the first electrode sheet 13 and the second electrode sheet 14 include a first top corner 101, a second top corner 102, a first bottom corner 103, and a second bottom corner 104. The first bottom corner 103 and the first top corner 101 are on the same side, and the second bottom corner 104 and the second top corner 102 are on the same side. The setting methods for each corner can be:

[0119] The first vertex angle 101 of the first pole piece 13 is set as the first cut-off corner structure R, and the first vertex angle 101 of the second pole piece 14 is set as the second cut-off corner structure r; or, the first vertex angle 101 of the first pole piece 13 is set as the second cut-off corner structure r, and the first vertex angle 101 of the second pole piece 14 is set as the first cut-off corner structure R;

[0120] The second vertex angle 102 of the first pole piece 13 is set as the first cut-off corner structure R, and the second vertex angle 102 of the second pole piece 14 is set as the second cut-off corner structure r; or, the second vertex angle 102 of the first pole piece 13 is set as the second cut-off corner structure r, and the second vertex angle 102 of the second pole piece 14 is set as the first cut-off corner structure R;

[0121] The first bottom angle 103 of the first pole piece 13 is set as the first cut-off corner structure R, and the first bottom angle 103 of the second pole piece 14 is set as the second cut-off corner structure r; or, the first bottom angle 103 of the first pole piece 13 is set as the second cut-off corner structure r, and the first bottom angle 103 of the second pole piece 14 is set as the first cut-off corner structure R;

[0122] The second bottom angle 104 of the first pole piece 13 is set as the first cut-off corner structure R, and the second bottom angle 104 of the second pole piece 14 is set as the second cut-off corner structure r; or, the second bottom angle 104 of the first pole piece 13 is set as the second cut-off corner structure r, and the second bottom angle 104 of the second pole piece 14 is set as the first cut-off corner structure R.

[0123] As long as the corners of the first pole piece 13 and the second pole piece 14 satisfy the above setting method, it can be ensured that after the first pole piece 13 and the second pole piece 14 are stacked, at the same corner, one first cut-off corner structure R and one second cut-off corner structure r are satisfied.

[0124] As Figures 5 to 7 shown, the difference between the negative electrode sheet 12 and the positive electrode sheet 11 is that, on the one hand, the negative electrode sheet 12 is larger than the positive electrode sheet 11, and on the other hand, the direction of the tab of the negative electrode sheet 12 is opposite to that of the positive electrode sheet 11. And the negative electrode sheet 12 is stacked in the form of "……the first pole piece 13 - the second pole piece 14 - the first pole piece 13 - the second pole piece 14……". Therefore, the setting method of the first pole piece 13 and the second pole piece 14 of the negative electrode sheet 12 can refer to the above conditions and will not be elaborated here.

[0125] It should be noted that the form of the first pole piece 13 of the negative electrode sheet 12 and the first pole piece 13 of the positive electrode sheet 11 can be the same or different. The form of the second pole piece 14 of the negative electrode sheet 12 and the second pole piece 14 of the positive electrode sheet 11 can be the same or different. However, as long as the forms of the cut-off corner structures 3 at the same corner of the first pole piece 13 and the second pole piece 14 in the same kind of pole piece 1 are different (the forms of the cut-off corner structure 3 include the first cut-off corner structure R and the second cut-off corner structure r).

[0126] Specifically, in this embodiment, the structural forms of the positive electrode sheet 11 and the negative electrode sheet 12 are the same, that is, the structural form of the first electrode sheet 13 of the positive electrode sheet 11 is the same as that of the first electrode sheet 13 of the negative electrode sheet 12, and the structural form of the second electrode sheet 14 of the positive electrode sheet 11 is the same as that of the second electrode sheet 14 of the negative electrode sheet 12.

[0127] Specifically, the first apex angle 101 and the second apex angle 102 of the first electrode sheet 13 include a first cutout structure R, and the first base angle 103 and the second base angle 104 of the first electrode sheet 13 include a second cutout structure r.

[0128] Specifically, the first base angle 103 and the second base angle 104 of the second electrode sheet 14 include a first cutout structure R, and the first apex angle 101 and the second apex angle 102 of the second electrode sheet 14 include a second cutout structure r.

[0129] As Figure 9 shown, and described in the direction of Figure 9 ..., the form of the stacked cell is from top to bottom as "... separator 2 - the first electrode sheet 13 of the negative electrode sheet 12 - separator 2 - the first electrode sheet 13 of the positive electrode sheet 11 - separator 2 - the second electrode sheet 14 of the negative electrode sheet 12 - separator - the second electrode sheet 14 of the positive electrode sheet 11...".

[0130] Optionally, in this embodiment, the cutout structure 3 can be formed by die cutting with a metal mold or laser cutting. Preferably, the cutout structure 3 in this embodiment is a rounded corner, and the rounded corner is cut by laser.

[0131] Furthermore, when the cutout structure 3 is a rounded corner and is cut by laser, the quality of the first cutout structure R is better than that of the second cutout structure r. The specific principle is as follows:

[0132] The light output of the laser is a dot-shaped light spot, and the laser cuts into a line by the coincidence of the light spots. In the straight cutting section, the moving speed of the laser is the fastest, but when it encounters a turn, the laser speed will decrease, but the laser light output is still continuous. At this time, the coincidence rate of the light spots is very high. Further, the smaller the turning radius, the higher the coincidence rate of the laser light spots, the more obvious the aggregation of laser energy, and thus the worse the cutting quality.

[0133] Therefore, when the cutout structure 3 is a rounded corner, the radius of the first cutout structure R is larger than that of the second cutout structure r, that is, the quality of the first cutout structure R is better than that of the second cutout structure r, which is reflected in that the burr length of the first cutout structure R is smaller than that of the second cutout structure r.

[0134] It should be noted that both the first chamfered structure R and the second chamfered structure r are qualified rounded corner structures. However, the quality of the first chamfered structure R is better than that of the second chamfered structure r (superior angle and sub-superior angle), and it should not be understood that the second chamfered structure r after cutting is an unqualified rounded corner.

[0135] The applicant conducted experiments on this. After cutting the first chamfered structure R and the second chamfered structure r on the tape, both were placed under an electron microscope for observation and measurement of the burr length. The experimental results are as Figure 40 .

[0136] Figure 40 The upper picture shows that after cutting the second chamfered structure r, the cutting position was observed with an electron microscope, and the burr data was measured. The measurement results were 11.55μm, 11.20μm, 19.21μm, 15.60μm, and 16.93μm respectively.

[0137] Figure 40 The lower picture shows that after cutting the first chamfered structure R, the cutting position was observed with an electron microscope, and the burr data was measured. The measurement results were 9.11μm and 10.11μm respectively.

[0138] It can be seen that both the number and length of burrs after cutting the first chamfered structure R are less than those after cutting the second chamfered structure r.

[0139] Based on this, as Figure 9 shown, actually in the stacked battery cell of this embodiment, at the first chamfered structure R of the positive electrode sheet 11, pressure transmitted layer by layer from the electrode sheets 1 will still be received during the hot pressing process. However, as described above, the first chamfered structure R is a superior angle, with short and few burrs, and the probability of the burrs piercing the separator is relatively low. But at the second chamfered structure r of the positive electrode sheet 11, there is a hollowed-out area below it (i.e., the area where the second chamfered structure r protrudes from the first chamfered structure R). Therefore, although the sub-superior angle has longer and more burrs, the hollowed-out area below it can buffer and reduce the pressure, so that the pressure will not be transmitted layer by layer by the electrode sheet 1, making the probability of the burrs piercing the separator relatively small during the hot pressing process.

[0140] Furthermore, the negative electrode sheet 12 also has a superior angle and a sub-superior angle. However, as described above, in the "negative wrapping positive" structural form of the stacked battery cell, there is a hollowed-out area formed by the positive electrode sheet 11 between the negative electrode sheets 12. Therefore, the risk of the burrs piercing the separator is not great.

[0141] In summary, compared with the stacked battery cell stacked with traditional single-size specification electrode sheets (the negative electrode sheet is of a unified specification, and the positive electrode sheet is of a unified specification), the overall risk of the burrs piercing the separator during the hot pressing process of the stacked battery cell of this embodiment is significantly reduced.

[0142] Optionally, the size of the first chamfered structure R is in the range of 1 mm to 5 mm.

[0143] Specifically, the first chamfered structure R is a rounded corner, and its size can be R1, R2, R3, R4, R5, etc.

[0144] Optionally, the size of the second chamfered structure r is in the range of 0.2 mm to 2 mm.

[0145] Specifically, the second chamfered structure r is a rounded corner, and its size can be r0.2, r0.6, r1, r1.5, r2, etc.

[0146] However, it is necessary to satisfy that the size of the first chamfered structure R is larger than that of the second chamfered structure r.

[0147] Optionally, the calculation formulas for the first chamfered structure R and the second chamfered structure r can be:

[0148] R = r + (0.5 - 3) mm.

[0149] Wherein, R is the size of the first chamfered structure R, and r is the size of the second chamfered structure r.

[0150] Optionally, the burr size generated after cutting the first chamfered structure R is in the range of 5 μm - 15 μm, and the burr size generated after cutting the second chamfered structure r is in the range of 5 μm - 20 μm.

[0151] Embodiment 2

[0152] As Figure 10 shown, the difference between Embodiment 2 and Embodiment 1 of the stacked battery cell according to the present application lies in the different forms of the first electrode sheet 13 and the second electrode sheet 14.

[0153] Specifically, the first top corner 101 and the second bottom corner 104 of the first electrode sheet 13 include the first chamfered structure R, and the second top corner 102 and the first bottom corner 103 of the first electrode sheet 13 include the second chamfered structure r.

[0154] Furthermore, the second top corner 102 and the first bottom corner 103 of the second electrode sheet 14 include the first chamfered structure R, and the first top corner 101 and the second bottom corner 104 of the second electrode sheet 14 include the second chamfered structure r.

[0155] Furthermore, the form of the first electrode sheet 13 of the positive electrode sheet 11 is the same as that of the first electrode sheet 13 of the negative electrode sheet 12, and the form of the second electrode sheet 14 of the positive electrode sheet 11 is the same as that of the second electrode sheet 14 of the negative electrode sheet 12.

[0156] Embodiment 3

[0157] As Figure 11As shown, the difference between the third embodiment and the first embodiment of the stacked battery cell according to the present application lies in the different forms of the first electrode tab 13 and the second electrode tab 14.

[0158] Specifically, the first top corner 101 and the first bottom corner 103 of the first electrode tab 13 include a first cut-off corner structure R, and the second top corner 102 and the second bottom corner 104 of the first electrode tab 13 include a second cut-off corner structure r.

[0159] Furthermore, the second top corner 102 and the second bottom corner 104 of the second electrode tab 14 include a first cut-off corner structure R, and the first top corner 101 and the first bottom corner 103 of the second electrode tab 14 include a second cut-off corner structure r.

[0160] Furthermore, the form of the first electrode tab 13 of the positive electrode sheet 11 is the same as that of the first electrode tab 13 of the negative electrode sheet 12, and the form of the second electrode tab 14 of the positive electrode sheet 11 is the same as that of the second electrode tab 14 of the negative electrode sheet 12.

[0161] Embodiment Four

[0162] As Figure 12 shown, the difference between the fourth embodiment and the first embodiment of the stacked battery cell according to the present application lies in the different forms of the first electrode tab 13 and the second electrode tab 14.

[0163] Specifically, the first top corner 101, the second top corner 102, the first bottom corner 103, and the second bottom corner 104 of the first electrode tab 13 all include a first cut-off corner structure R.

[0164] Furthermore, the first top corner 101, the second top corner 102, the first bottom corner 103, and the second bottom corner 104 of the second electrode tab 14 all include a second cut-off corner structure r.

[0165] Compared with the above three embodiments, for the stacked battery cell of Embodiment Four, the specifications of the four corners of the first electrode tab 13 are the same (all are the first cut-off corner structure r), and the specifications of the four corners of the second electrode tab 14 are the same (all are the second cut-off corner structure R). Therefore, the processing of the first electrode tab 13 and the second electrode tab 14 is easier.

[0166] Furthermore, the form of the first electrode tab 13 of the positive electrode sheet 11 is the same as that of the first electrode tab 13 of the negative electrode sheet 12, and the form of the second electrode tab 14 of the positive electrode sheet 11 is the same as that of the second electrode tab 14 of the negative electrode sheet 12.

[0167] II. Cutting Method of Electrode Tab

[0168] Embodiment One

[0169] As Figure 13 and Figure 14As shown, in the first embodiment of the pole piece cutting method according to the present application, the cutting method is used to cut the pole pieces of the above-mentioned stacked battery cells. And the cutting method is used to cut adjacent pole pieces 1, and to cut two top corners and another two bottom corners on the opposite sides of adjacent pole pieces 1. The pole piece cutting method specifically includes:

[0170] Step S1: The cutting mechanism cuts a first track 100 along a first direction of the width of the tape. The first track 100 cuts one of the top corners and one of the bottom corners, and cuts off adjacent pole pieces 1;

[0171] Step S2: The cutting mechanism cuts a second track 200 along a second direction of the width of the tape. The second track 200 cuts the other top corner and the other bottom corner, wherein the first direction and the second direction are opposite.

[0172] In this embodiment, cutting the top corners and bottom corners of the pole piece 1 is to cut the missing corner structure 3 in the above-mentioned embodiment, that is, in this embodiment, the missing corner structure 3 is processed together during the cutting of the pole piece 1.

[0173] Optionally, the cutting method in this embodiment uses laser cutting.

[0174] Furthermore, both the above-mentioned first direction and the second direction are along the direction perpendicular to the extension direction of the tape. For Figure 13 and Figure 14 illustration purposes, if the first direction is the upward direction, then the second direction is the downward direction. Of course, the first direction can also be the downward direction, and the second direction can be the upward direction.

[0175] As Figure 13 shown, after the first track 100 is cut, on the one hand, the sides of two adjacent pole pieces 1 are cut, and on the other hand, one bottom corner and one top corner are cut. Depending on the shape of the first track 100, the bottom corner and the top corner can be the top corner and the bottom corner on the same side of the same pole piece 1, or can be the top corner of one pole piece 1 and the bottom corner of another adjacent pole piece 1.

[0176] As Figure 14 shown, after the first track 100 is cut, the second track 200 is then cut. The second track cuts the remaining one bottom corner and the remaining one bottom corner.

[0177] Therefore, after the first track 100 and the second track 200 are cut, the side structures of two opposite pole pieces 1 can be cut.

[0178] Those skilled in the art can understand that by repeatedly performing step S1 and step S2 on the strip, multiple pole pieces 1 with the same specifications can be cut out. Among them, the strip can be continuously conveyed, the laser cutting device is fixedly arranged, and the laser cutting device adjusts the laser path through a galvanometer. When the strip moves to a certain cutting position, the laser cutting device cuts the first trajectory 100 and the second trajectory 200. After cutting, when the strip moves to the next cutting position, the laser cutting device cuts the first trajectory 100 and the second trajectory 200 again. The strip can also be fixedly arranged, and the laser cutting device is movably arranged above the strip through a linear driving mechanism. When the laser cutting device moves to a certain cutting position, it cuts the first trajectory 100 and the second trajectory 200. After cutting, when the laser cutting device moves to the next cutting position, it cuts the first trajectory 100 and the second trajectory 200 again.

[0179] In this embodiment, the first cutting method is adopted, that is, the strip is continuously conveyed, and the laser cutting device performs "pursuit cutting".

[0180] As Figure 13 and Figure 14 shown, in the technical solution of this embodiment, the first trajectory 100 includes a first arc segment 110, a first straight segment 120, and a second arc segment 130 connected in sequence along the direction from the starting point to the ending point, and the second trajectory 200 includes a spaced third arc segment 210 and a fourth arc segment 220 along the direction from the starting point to the ending point.

[0181] Specifically, the first arc segment 110 is used to cut the notch structure 3. According to the specific structure of the pole piece 1, the first arc segment 110 can cut the first notch structure R or the second notch structure r.

[0182] Furthermore, the first straight segment 120 is used to cut the side of the adjacent pole piece 1.

[0183] Furthermore, the second arc segment 130 is used to cut the notch structure 3. According to the specific structure of the pole piece 1, the second arc segment 130 can cut the first notch structure R or the second notch structure r.

[0184] Furthermore, the third arc segment 210 is used to cut the notch structure 3. According to the specific structure of the pole piece 1, the third arc segment 210 can cut the first notch structure R or the second notch structure r.

[0185] Furthermore, the fourth arc segment 220 is used to cut the notch structure 3. According to the specific structure of the pole piece 1, the fourth arc segment 220 can cut the first notch structure R or the second notch structure r.

[0186] It should be noted that the second trajectory 200 in this embodiment is not a continuous trajectory, and the third arc segment 210 and the fourth arc segment 220 are separated.

[0187] As Figure 13 , Figure 14 and Figure 17 shown, in the technical solution of this embodiment, the bending directions of the first arc segment 110 and the second arc segment 130 are opposite, and the first arc segment 110 and the second arc segment 130 are used to cut the adjacent pole pieces 1, the top angle of one pole piece 1 and the bottom angle of the other pole piece 1. The bending directions of the third arc segment 210 and the fourth arc segment 220 are opposite, and the third arc segment 210 and the fourth arc segment 220 are used to cut the adjacent pole pieces 1, the bottom angle of one pole piece 1 and the top angle of the other pole piece 1.

[0188] Combined with Figure 13 it can be seen that the opposite bending directions of the first arc segment 110 and the second arc segment 130 mean that the starting end of the first arc segment 110 extends toward the upstream of the strip, and the ending end of the second arc segment 130 extends toward the downstream of the strip. Such a setting is related to the flow direction of the strip. Specifically, in this embodiment, the strip flows along the Figure 13 right side in the shown direction, so the cutting direction of the first arc segment 110 is toward the flow direction of the strip. Similarly, the cutting direction of the second arc segment 130 is toward the flow direction of the strip. Such a setting makes the first trajectory 100 easy to cut.

[0189] Similarly, the starting end of the third arc segment 210 extends toward the upstream of the strip, and the ending end of the fourth arc segment 220 extends toward the downstream of the strip, so that the cutting direction of the third arc segment 210 is toward the flow direction of the strip, and the cutting direction of the fourth arc segment 220 is toward the flow direction of the strip. Such a setting makes the second trajectory 200 easy to cut.

[0190] In some embodiments not shown, if the strip is fixedly arranged and the laser cutting device is movably arranged, those skilled in the art can adjust the bending directions of each arc segment according to actual needs.

[0191] Furthermore, in the pole piece cutting method of this embodiment, steps S1 and S2 are used to cut the first pole piece 13 in the second embodiment of the above stacked battery cell.

[0192] Specifically, the first arc segment 110 and the second arc segment 130 are suitable for cutting the first cut-off corner structure R, and the third arc segment 210 and the fourth arc segment 220 are suitable for cutting the second cut-off corner structure r. Combined with Figure 10 and Figure 17As shown, those skilled in the art can understand that after the first track 100 and the second track 200 are cut at intervals on the strip, the form of the pole piece 1 is such that a set of opposite top corners and bottom corners are the first cut - out structure R, and the other set of opposite top corners and bottom corners are the second cut - out structure r. That is, the cut - out pole piece 1 has the form of Figure 10 the structure of the first pole piece 13 shown.

[0193] In this embodiment, the cut - out structure 3 cut from the first track 100 is significantly better than the cut - out structure 3 cut from the second track 200. The specific reasons are as follows:

[0194] 1. In laser cutting, the quality of the larger - sized first cut - out structure R is better than that of the smaller - sized second cut - out structure r. The reasons have been described in detail above, so they will not be elaborated here;

[0195] 2. Before cutting the first track 100, the strip is in a tensioned state, so the laser can achieve precise focusing and the cutting effect is the best. After the first track 100 is cut, the strip is cut off, and there are slight jitters and displacements at the edge (cut - off position) of the pole piece 1. When cutting the second track 200, the laser will inevitably be slightly defocused. Therefore, the overall cutting quality of the second track 200 is lower than that of the first track 100.

[0196] In summary, by making the first arc segment 110 and the second arc segment 130 cut the first cut - out structure R, and making the third arc segment 210 and the fourth arc segment 220 cut the second cut - out structure r, it is ensured that the first cut - out structure R is of the best quality (the second cut - out structure r is of sub - optimal quality but also a qualified rounded corner). Especially in a stacked - cell battery, at the corner position of the first cut - out structure R of the positive electrode piece 11, the length and quantity of burrs are minimized as much as possible, reducing the risk of burrs piercing the separator.

[0197] As Figure 15 and Figure 16 shown, in the technical solution of this embodiment, a slit is provided on the cutting table. When cutting, the above - mentioned first straight - line segment 120 cuts at the slit, so the laser does not directly cut the surface of the cutting table, preventing equipment damage. Further, an adsorption mechanism and a dust - removal mechanism are provided below the slit.

[0198] From Figure 15 and Figure 16 it can also be seen that an arc structure is provided at the edge of the slit, that is, the corner position of the slit is not a right angle but an arc - chamfered structure.

[0199] An adsorption mechanism is provided at the slit. The adsorption structure can fix the edge of the cut pole piece 1, minimizing the jitter of the edge of the pole piece 1 as much as possible. Specifically, since an arc structure is provided at the edge of the slit, after the adjacent pole pieces 1 are cut, under the negative pressure suction of the adsorption structure, the side of the pole piece 1 can fit down along the arc surface of the arc structure at the slit, thus achieving the effect of fixing the side of the pole piece 1.

[0200] A dust removal mechanism is also provided at the slit. The dust removal mechanism can adsorb and remove the dust generated after cutting. And the adsorption force generated by the dust removal mechanism can also assist in fixing the side of the pole piece 1.

[0201] As Figure 17 and Figure 18 shown, the pole piece cutting method further includes:

[0202] Step S3: After repeatedly executing Step S1 and Step S2 and cutting a preset number of first pole pieces 13, change the types of cutting chamfers of the first arc segment 110, the second arc segment 130, the third arc segment 210, and the fourth arc segment 220 to obtain the third trajectory 300 and the fourth trajectory 400;

[0203] Step S4: The cutting mechanism cuts the third trajectory 300 along the third direction of the width of the tape. The third trajectory 300 cuts one of the top corners and one of the bottom corners, and cuts the adjacent pole pieces 1;

[0204] Step S5: The cutting mechanism cuts the fourth trajectory 400 along the fourth direction of the width of the tape. The fourth trajectory 400 cuts the other top corner and the other bottom corner;

[0205] Step S6: Repeatedly execute Step S4 and Step S5 and cut a preset number of second pole pieces 14.

[0206] Among them, the change of the cutting chamfer type includes changing the first notch structure R to the second notch structure r, or changing the second notch structure r to the first notch structure R. The third direction and the fourth direction are opposite, the third direction is the same as the first direction, or the third direction is the same as the second direction.

[0207] Specifically, as described above, after repeatedly performing Step S1 and Step S2 on the tape, a preset number of first pole pieces 13 can be cut. After manufacturing the first pole pieces 13, it is also necessary to manufacture the second pole pieces 14.

[0208] According to the above content, since the first pole piece 13 and the second pole piece 14 satisfy that at the same corner, one is provided with the first cut-off corner structure R and the other is provided with the second cut-off corner structure r (which can be understood as mutually exclusive). Therefore, when cutting the second pole piece 14, it is necessary to transform the first trajectory 100 and the second trajectory 200. The transformation method is to transform the 3 types of cut-off corner structures cut by each arc segment, so as to obtain the trajectory for cutting the second pole piece 14.

[0209] As Figure 17 and Figure 18 shown, in the first trajectory 100, changing the cutting of the first cut-off corner structure R of the first arc segment 110 to cutting the second cut-off corner structure r, and changing the cutting of the first cut-off corner structure R of the second arc segment 130 to cutting the second cut-off corner structure r, thus obtaining the third trajectory 300.

[0210] As Figure 17 and Figure 18 shown, in the second trajectory 200, changing the cutting of the second cut-off corner structure r of the third arc segment 210 to cutting the first cut-off corner structure R, and changing the cutting of the second cut-off corner structure r of the fourth arc segment 220 to cutting the first cut-off corner structure R, thus obtaining the fourth trajectory 400.

[0211] As Figure 19 shown, by reciprocally cutting the third trajectory 300 and the fourth trajectory 400 on the strip, multiple second pole pieces 14 can be manufactured.

[0212] It should be noted that step S4 can be carried out before step S5, that is, first cut the third trajectory 300 and then cut the fourth trajectory 400.

[0213] Since the cut-off corner structure 3 cut by the third trajectory 300 is the second cut-off corner structure r, and the cut-off corner structure 3 cut by the fourth trajectory 400 is the first cut-off corner structure R. As shown above, cutting the third trajectory 300 first will cause the first cut-off corner structure R not to reach the optimal state. Therefore, it is also possible to make step S5 before step S4, that is, first cut the first cut-off corner structure R of the fourth trajectory 400, so that the first cut-off corner structure R can reach the optimal state, with the number of burrs as small as possible and the length of the burrs as short as possible.

[0214] Furthermore, when cutting the positive pole piece 11 and the negative pole piece 12, the above steps 1 to 6 can be adopted. However, since the size of the negative pole piece 12 is larger than that of the positive pole piece, when cutting the negative pole piece 12, it is necessary to increase the length of the first straight segment 120 in the first trajectory 100 and the third trajectory 300.

[0215] Embodiment 2

[0216] As Figures 20 to 23As shown, compared with the first embodiment of the method for cutting the pole piece according to the application, the difference lies in the different types of the cut-off corner structures 3 of each arc segment.

[0217] As Figures 20 to 23 shown, specifically, the types of the cut-off corner structures of the first arc segment 110 and the fourth arc segment 220 are the same, the types of the cut-off corner structures of the second arc segment 130 and the third arc segment 210 are the same, and the types of the cut-off corner structures of the first arc segment 110 and the second arc segment 130 are different. Among them, the types of the cut-off corner structures 3 include the first cut-off corner structure R and the second cut-off corner structure r.

[0218] By cutting along the first trajectory 100 and the second trajectory 200, the types of the cut-off corner structures 3 of the two top corners of the pole piece 1 are the same, the types of the cut-off corner structures 3 of the two bottom corners are the same, and the types of the cut-off corner structures 3 of the top corners and the bottom corners are different.

[0219] Those skilled in the art can understand that the pole piece 1 cut in the second embodiment is the first pole piece 13 and the second pole piece 14 in the first embodiment of the stacked battery cell above.

[0220] Specifically in the second embodiment, the first arc segment 110 cuts the second cut-off corner structure r, the second arc segment 130 cuts the first cut-off corner structure R, the third arc segment 210 cuts the first cut-off corner structure R, and the fourth arc segment 220 cuts the second cut-off corner structure r. Therefore, after the first trajectory 100 and the second trajectory 200 cut the strip, the formed pole piece 1 is in the form that the two top corners are the first cut-off corner structure R and the two bottom corners are the second cut-off corner structure r, that is, Figure 2 the first pole piece 13 in

[0221] As Figure 22 and Figure 23 shown, the way to change the trajectory for cutting the second pole piece 14 in the second embodiment is as follows:

[0222] In the first trajectory 100, changing the cutting of the second cut-off corner structure r of the first arc segment 110 to cutting the first cut-off corner structure R, and changing the cutting of the first cut-off corner structure R of the second arc segment 130 to cutting the second cut-off corner structure r, thus obtaining the third trajectory 300.

[0223] In the second trajectory 200, changing the cutting of the first cut-off corner structure R of the third arc segment 210 to cutting the second cut-off corner structure r, and changing the cutting of the second cut-off corner structure r of the fourth arc segment 220 to cutting the first cut-off corner structure R, thus obtaining the fourth trajectory 400.

[0224] Those skilled in the art can understand that by reciprocally cutting the third trajectory 300 and the fourth trajectory 400 on the strip, multiple second pole pieces 14 can be fabricated. The form of the second pole piece 14 is such that two top corners are of the second notch structure r, and two bottom corners are of the first notch structure R, that is Figure 2 the second pole piece 14 in

[0225] Embodiment III

[0226] As Figures 24 to 27 shown, compared with the above Embodiment I of the cutting method of the pole piece according to the application, the difference lies in that the types of the notch structures 3 of the cutting of each arc segment are different.

[0227] Specifically, the types of the notch structures of the first arc segment 110 and the third arc segment 210 are the same, the types of the notch structures 3 of the second arc segment 130 and the fourth arc segment 220 are the same, and the notch structures 3 of the first arc segment 110 and the second arc segment 130 are different. Among them, the types of the notch structures 3 include the first notch structure R and the second notch structure r.

[0228] By cutting through the first trajectory 100 and the second trajectory 200, the types of the notch structures 3 of the top corners and the bottom corner structures on the same side of the pole piece 1 are the same, the types of the notch structures 3 of the top corners and the bottom corner structures on the other side of the pole piece 1 are the same, and the types of the notch structures 3 at the corners on different sides are different.

[0229] Those skilled in the art can understand that the pole piece 1 cut in Embodiment II is the first pole piece 13 and the second pole piece 14 in Embodiment III of the above stacked battery cell.

[0230] Specifically in Embodiment III, the first arc segment 110 cuts the second notch structure r, the second arc segment 130 cuts the first notch structure R, the third arc segment 210 cuts the second notch structure r, and the fourth arc segment 220 cuts the first notch structure R. Therefore, after the first trajectory 100 and the second trajectory 200 cut the strip, the form of the pole piece 1 formed is such that the top corners and the bottom corners on the left side are of the first notch structure R, and the top corners and the bottom corners on the right side are of the second notch structure r, that is Figure 11 the first pole piece 13 in

[0231] As Figure 26 and Figure 27 shown, the way to change the trajectory for cutting the second pole piece 14 in Embodiment III is as follows:

[0232] In the first trajectory 100, changing the cutting of the second notch structure r for the first arc segment 110 to cutting the first notch structure R, and changing the cutting of the first notch structure R for the second arc segment 130 to cutting the second notch structure r, thus obtaining the third trajectory 300.

[0233] In the second track 200, the third arc segment 210 for cutting the second cut-off corner structure r is changed to cutting the first cut-off corner structure R, and the fourth arc segment 220 for cutting the first cut-off corner structure R is changed to cutting the second cut-off corner structure r, thereby obtaining the fourth track 400.

[0234] Those skilled in the art can understand that after reciprocally cutting the third track 300 and the fourth track 400 on the strip, multiple second pole pieces 14 can be manufactured. The form of the second pole piece 14 is that the top corners and bottom corners on the left side are the second cut-off corner structures r, and the top corners and bottom corners on the right side are the first cut-off corner structures R, that is, Figure 11 the second pole piece 14 in

[0235] Embodiment 4

[0236] As Figures 28 to 31 shown, compared with Embodiment 3 of the pole piece cutting method according to the present application, the difference in Embodiment 4 is that the structures of the first track 100 and the second track 200 are different.

[0237] Specifically, the bending directions of the first arc segment 110 and the second arc segment 130 are the same, and the first arc segment 110 and the second arc segment 130 are used to cut the top corners and bottom corners of one pole piece 1 among adjacent pole pieces 1. The bending directions of the third arc segment 210 and the fourth arc segment 220 are the same, and the third arc segment 210 and the fourth arc segment 220 are used to cut the bottom corners and top corners of the other pole piece 1 among adjacent pole pieces 1.

[0238] From Figure 28 it can be seen that the starting end of the first arc segment 110 extends towards the downstream of the strip, and the end of the second arc segment 130 also extends towards the downstream of the strip.

[0239] From Figure 29 it can be seen that the starting end of the third arc segment 210 extends towards the upstream of the strip, and the end of the fourth arc segment 220 extends towards the upstream of the strip.

[0240] The first track 100 and the second track 200 in Embodiment 4 also cut the first pole piece 13 in Embodiment 3 of the above-mentioned stacked battery cell.

[0241] As Figures 28 to 30 shown, the first arc segment 110 cuts the first cut-off corner structure R, the second arc segment 130 cuts the first cut-off corner structure R, the third arc segment 210 cuts the second cut-off corner structure r, and the fourth arc segment 220 cuts the second cut-off corner structure r. Therefore, after the first track 100 and the second track 200 cut the strip, the formed pole piece 1 has the form that the top corners and bottom corners on the left side are the first cut-off corner structures R, and the top corners and bottom corners on the right side are the second cut-off corner structures r, that is, Figure 11 the first pole piece 13 in

[0242] Compared with the technical solution of embodiment 3, the fourth embodiment also has the same cutting Figure 11 In the case of the first pole piece 13 shown, it is ensured that the first corner-cut structure R is cut in the first track 100 that is cut first, and the first corner-cut structure R is ensured to be of optimal quality.

[0243] like Figure 30 and Figure 31 As shown, the method of cutting the second pole piece 14 to change the trajectory in the fourth embodiment is:

[0244] In the first trajectory 100 , the first arc segment 110 changes cutting of the first notched corner structure R to cutting of the second notched corner structure r, and the second arc segment 130 changes cutting of the first notched corner structure R to cutting of the second notched corner structure r, thereby obtaining the third trajectory 300 .

[0245] In the second track 200 , the third arc segment 210 is changed from cutting the second notched structure r to cutting the first notched structure R, and the fourth arc segment 220 is changed from cutting the second notched structure r to cutting the first notched structure R, thereby obtaining the fourth track 400 .

[0246] Those skilled in the art can understand that by reciprocatingly cutting the third track 300 and the fourth track 400 on the material strip, multiple second pole pieces 14 can be produced. The second pole piece 14 is in the form of a second notched corner structure r at the top and bottom corners on the left, and a first notched corner structure R at the top and bottom corners on the right, that is, Figure 11 The second pole piece 14 in.

[0247] Combined with the description of the cutting method in the first embodiment, when cutting the second pole piece 14 , the fourth track 400 may be cut first to ensure that the first cutting track is to cut the first corner-cut structure R, and ensure that the first corner-cut structure R is in the best quality.

[0248] like Figure 30 As shown, the end point of the third arc segment 210 is connected to the end point of the first straight line segment 120, and the starting point of the fourth arc segment 220 is connected to the starting point of the first straight line segment 120. Specifically, the end point of the third arc segment 210 is also the end point of the missing corner structure 3 at the top corner, and the end point of the third arc segment 210 is connected to the end point of the first straight line segment 120, that is, the intersection position of the missing corner structure 3 at the top corner and the side of the pole piece 1 is cut out. The starting point of the fourth arc segment 220 is also the starting point of the missing corner structure 3 at the bottom corner, and the starting point of the fourth arc segment 220 is connected to the starting point of the first straight line segment 120, that is, the intersection position of the missing corner structure 3 at the bottom corner and the side of the pole piece 1 is cut out.

[0249] However, in the above cutting method, if the cutting error causes the end point of the third arc segment 210 not to connect with the end point of the first straight segment 120, or the starting point of the fourth arc segment 220 not to connect with the starting point of the first straight segment 120, it will result in the missing corner structure 3 not being completely cut off and waste pieces being generated.

[0250] Furthermore, in order to prevent the end point or starting point of the missing corner structure 3 from not being cut due to cutting errors, the third arc segment 210 and the fourth arc segment 220 can be optimized.

[0251] As shown in FIG. 32, the third arc segment 210 passes through the end point of the first straight segment 120, and the intersection point is located between the starting point and the end point of the third arc segment 210. The fourth arc segment 220 passes through the starting point of the first straight segment 120, and the intersection point is located between the starting point and the end point of the fourth arc segment 220.

[0252] In Figure 32 the cutting trajectory, the end point of the third arc segment 210 passes through a certain distance beyond the end point of the first straight segment 120 to ensure that the end point of the missing corner structure 3 at the top corner of the pole piece 1 is cut off. And the starting point of the fourth arc segment 220 is located a certain distance above the first straight segment 120 ( Figure 32 as shown in the figure) to ensure that the starting point of the missing corner structure 3 at the bottom corner of the pole piece 1 is cut off.

[0253] In order to ensure that the missing corner structures 3 at the top and bottom corners of the pole piece 1 can be cut off, the second trajectory 200 can be further optimized.

[0254] As Figure 33 shown, the second trajectory 200 further includes a second straight segment 230. The second straight segment 230 is connected between the third arc segment 210 and the fourth arc segment 220, and the second straight segment 230 coincides with or is offset from the first straight segment 120.

[0255] Specifically, the starting point of the second straight segment 230 is connected to the end point of the third arc segment 210, and the end point of the second straight segment 230 is connected to the starting point of the fourth arc segment 220. By cutting the second trajectory in this way, it can be ensured that the cutting trajectories of the top corner, the side edge, and the bottom corner on the same side of the pole piece 1 are complete, and there will be no situation where the missing corner structure 3 is not cut off.

[0256] Combined with Figure 28 and Figure 33 shown, after setting the second straight segment 230, the first trajectory 100 and the second trajectory 200 will have two straight segments, namely the first straight segment 120 and the second straight segment 230.

[0257] Among them, one setting method of the first straight segment 120 and the second straight segment 230 is as Figure 34As shown, the first straight line segment 120 and the second straight line segment 230 have overlapping trajectories. Figure 15 and Figure 16 As shown, after the first straight line segment 120 is cut, the adsorption mechanism and the dust removal mechanism below the slit work together, and the adsorption force causes the two sides of the slit to deform slightly downward, so that the side of the pole piece 1 fits the arc chamfer of the slit. This increases the width between the sides of the two pole pieces 1 after cutting. Therefore, even if the trajectory of the second straight line segment 230 overlaps with the trajectory of the first straight line segment 120, the second straight line segment 230 will not repeatedly cut the side of the pole piece 1, preventing the appearance of additional burrs and controlling the generation of molten beads, which is beneficial to controlling the quality of the pole piece 1.

[0258] At the same time, the width between the side edges of the two pole pieces 1 after cutting is increased, and the control of the laser return trajectory (ie, the second straight line segment 230) is also facilitated.

[0259] Furthermore, another configuration of the first straight line segment 120 and the second straight line segment 230 is as follows: Figure 35 As shown, the first straight line segment 120 and the second straight line segment 230 are arranged in a staggered manner. Figure 35 It can be seen that after the first straight line segment 120 and the second straight line segment 230 are set in this way, the area cut between the first track 100 and the second track 200 is a complete area. In addition, the top corner, bottom corner and side edge of the pole piece 1 on one side are cut continuously, and the top corner, bottom corner and side edge of the pole piece 1 on the other side are also cut continuously, ensuring that the side edges of each pole piece will not be cut repeatedly when the corner-cut structure 3 can be cut off. Figure 35 Compared with the cropping method in Figure 34 As for the cutting method in the middle, more waste will be generated.

[0260] Embodiment 5

[0261] like Figures 36 to 39 As shown, compared with the above-mentioned embodiment 1, the fifth embodiment of the pole piece cutting method of the application is different in that the types of the notched corner structures 3 cut in each arc segment are different.

[0262] Specifically, the first arc segment 110 , the second arc segment 130 , the third arc segment 210 and the fourth arc segment 220 are cut into the same type of notched corner structures, which include a first notched corner structure R and a second notched corner structure r.

[0263] The first track 100 and the second track 200 are used for cutting, so that the missing corner structures 3 at the four corners of the pole piece 1 are of the same type, that is, the missing corner structures 3 at the four corners are all the first missing corner structures R or the second missing corner structures r.

[0264] Those skilled in the art can understand that the cut pole piece 1 in Embodiment 5 is the first pole piece 13 and the second pole piece 14 in Embodiment 4 of the above-mentioned stacked cell.

[0265] Specifically in Embodiment 5, the first arc segment 110 is for cutting the second notch structure r, the second arc segment 130 is for cutting the second notch structure r, the third arc segment 210 is for cutting the second notch structure r, and the fourth arc segment 220 is for cutting the second notch structure r. Therefore, after the first track 100 and the second track 200 cut the strip, the formed pole piece 1 is in the form that the notch structures 3 at the four corners are all the second notch structure r, that is Figure 12 the first pole piece 13 in

[0266] As Figure 38 and Figure 39 shown, the way to change the track of cutting the second pole piece 14 in Embodiment 2 is:

[0267] In the first track 100, changing the cutting of the second notch structure r for the first arc segment 110 to cutting the first notch structure R, and changing the cutting of the second notch structure r for the second arc segment 130 to cutting the first notch structure R, thus obtaining the third track 300.

[0268] In the second track 200, changing the cutting of the second notch structure r for the third arc segment 210 to cutting the first notch structure R, and changing the cutting of the second notch structure r for the fourth arc segment 220 to cutting the first notch structure R, thus obtaining the fourth track 400.

[0269] Those skilled in the art can understand that by reciprocally cutting the third track 300 and the fourth track 400 on the strip, multiple second pole pieces 14 can be manufactured. The form of the second pole piece 14 is that the notch structures 3 at the four corners are all the first notch structure R, that is Figure 12 the second pole piece 14 in

[0270] Furthermore, the first track 100 and the second track 200 in Embodiment 5 can be adjusted with reference to the respective forms of the first track 100 and the second track 200 in Embodiment 4:

[0271] For example, the first arc segment 110 and the second arc segment 130 of the first track 100 in Embodiment 5 can be set to bend towards the same side, and the third arc segment 210 and the fourth arc segment 220 of the second track 200 can be set to bend towards the other same side;

[0272] For another example, the second trajectory 200 in the fifth embodiment may be set such that the end point of the third arc segment 210 is connected to the end point of the first straight segment 120, and the starting point of the fourth arc segment 220 is connected to the starting point of the first straight segment 120; or, the third arc segment 210 passes through the end point of the first straight segment 120, and the intersection point is located between the starting point and the end point of the third arc segment 210, and the fourth arc segment 220 passes through the starting point of the first straight segment 120, and the intersection point is located between the starting point and the end point of the fourth arc segment 220;

[0273] For another example, the second trajectory 200 in the fifth embodiment may be provided with a second straight segment 230, and the trajectories of the first straight segment 120 and the second straight segment 230 may coincide or be offset from each other.

[0274] The present application also provides a battery. The battery embodiment according to the present application includes a housing and a stacked battery cell disposed in the housing, and the stacked battery cell is the above-mentioned stacked battery cell.

[0275] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A laminated battery cell, characterized in that: The invention comprises a pole piece (1) and a diaphragm (2) stacked in sequence, wherein the pole piece (1) comprises a positive pole piece (11) and a negative pole piece (12), the positive pole piece (11) and the negative pole piece (12) are stacked in sequence, the negative pole piece (12) is larger than the positive pole piece (11), and the outer contour of the negative pole piece (12) protrudes from the outer contour of the positive pole piece (11), and a notched corner structure (3) is provided at the corner of the pole piece (1); In at least two adjacent pole pieces (1), at the same corner position, one of the pole pieces (1) is provided with a first corner-cut structure (R), and the other pole piece (1) is provided with a second corner-cut structure (r), wherein the size of the first corner-cut structure (R) is larger than the size of the second corner-cut structure (r), so that the second corner-cut structure (r) protrudes from the first corner-cut structure (R), and a hollow area exists at the same corner position; The pole piece (1) of the same polarity comprises a first pole piece (13) and a second pole piece (14); at any one of the four corners of the first pole piece (13) and the second pole piece (14), the first pole piece (13) is provided with one of the first corner-cut structure (R) and the second corner-cut structure (r), and the second pole piece (14) is provided with the other of the first corner-cut structure (R) and the second corner-cut structure (r); Wherein, in at least two adjacent positive electrode sheets (11), located at the same corner, the first electrode sheet (13) in the positive electrode sheet (11) is provided with the first corner-cut structure (R), and the second electrode sheet (14) in the positive electrode sheet (11) is provided with the second corner-cut structure (r).

2. The laminated battery cell according to claim 1, characterized in that: In at least two adjacent negative electrode sheets (12), located at the same corner, one of the negative electrode sheets (12) is provided with the first corner-cut structure (R), and the other negative electrode sheet (12) is provided with the second corner-cut structure (r).

3. The laminated battery cell according to claim 1, characterized in that: The first pole piece (13) and the second pole piece (14) both comprise a first top angle (101), a second top angle (102), a first bottom angle (103) and a second bottom angle (104), the first bottom angle (103) and the first top angle (101) are located on the same side, and the second bottom angle (104) and the second top angle (102) are located on the same side, wherein: The first top corner (101) includes the first notch structure (R) or the second notch structure (r); and / or, The second top corner (102) includes the first notch structure (R) or the second notch structure (r); and / or, The first bottom corner (103) includes the first corner-cut structure (R) or the second corner-cut structure (r); and / or, The second bottom corner (104) comprises the first notch structure (R) or the second notch structure (r).

4. The laminated battery cell according to claim 3, characterized in that: The first top corner (101) and the second bottom corner (104) of the first pole piece (13) include the first missing corner structure (R), and the second top corner (102) and the first bottom corner (103) of the first pole piece (13) include the second missing corner structure (r); The second top corner (102) and the first bottom corner (103) of the second pole piece (14) include the first missing corner structure (R), and the first top corner (101) and the second bottom corner (104) of the second pole piece (14) include the second missing corner structure (r).

5. The laminated battery cell according to claim 3, characterized in that: The first top corner (101) and the second top corner (102) of the first pole piece (13) include the first missing corner structure (R), and the first bottom corner (103) and the second bottom corner (104) of the first pole piece (13) include the second missing corner structure (r); The first bottom corner (103) and the second bottom corner (104) of the second pole piece (14) include the first missing corner structure (R), and the first top corner (101) and the second top corner (102) of the second pole piece (14) include the second missing corner structure (r).

6. The laminated battery cell according to claim 3, characterized in that: The first top angle (101) and the first bottom angle (103) of the first pole piece (13) include the first missing angle structure (R), and the second top angle (102) and the second bottom angle (104) of the first pole piece (13) include the second missing angle structure (r); The second top corner (102) and the second bottom corner (104) of the second pole piece (14) include the first missing corner structure (R), and the first top corner (101) and the first bottom corner (103) of the second pole piece (14) include the second missing corner structure (r).

7. The laminated battery cell according to claim 3, characterized in that: The first top angle (101), the second top angle (102), the first bottom angle (103) and the second bottom angle (104) of the first pole piece (13) all include the first missing angle structure (R); The first top angle (101), the second top angle (102), the first bottom angle (103) and the second bottom angle (104) of the second pole piece (14) all comprise the second missing angle structure (r).

8. The laminated battery cell according to any one of claims 1 to 2, characterized in that: The notched corner structure (3) includes a rounded corner, the size of the first notched corner structure (R) is in the range of 1 mm to 5 mm, the size of the second notched corner structure (r) is in the range of 0.2 mm to 2 mm, the size of the burr generated after cutting the first notched corner structure (R) is in the range of 5 μm-15 μm, and the size of the burr generated after cutting the second notched corner structure (r) is in the range of 5 μm-20 μm.

9. The laminated battery cell according to any one of claims 1 to 2, characterized in that: The missing corner structure (3) is formed by metal die cutting or laser cutting.

10. A pole piece cutting method, characterized in that: Used for cutting pole pieces of a laminated battery cell as claimed in any one of claims 1 to 8, and used for cutting adjacent pole pieces (1), and cutting two top corners and two other bottom corners on opposite sides of adjacent pole pieces (1), the pole piece cutting method comprising: Step S1: a cutting mechanism cuts a first track (100) along a first direction of the width of the material strip, wherein the first track (100) cuts one of the top corners and one of the bottom corners, and cuts off the adjacent pole pieces (1); Step S2: the cutting mechanism cuts a second track (200) along a second direction of the width of the material strip, wherein the second track (200) cuts another top corner and another bottom corner. The first direction is opposite to the second direction.

11. The pole piece cutting method according to claim 10, characterized in that: The first trajectory (100) comprises a first arc segment (110), a first straight line segment (120) and a second arc segment (130) connected in sequence along the direction from the starting point to the end point, and the second trajectory (200) comprises a third arc segment (210) and a fourth arc segment (220) spaced apart along the direction from the starting point to the end point.

12. The pole piece cutting method according to claim 11, characterized in that: The end point of the third arc segment (210) is connected to the end point of the first straight line segment (120), and the starting point of the fourth arc segment (220) is connected to the starting point of the first straight line segment (120); or, the third arc segment (210) passes through the end point of the first straight line segment (120), and the intersection point is located between the starting point and the end point of the third arc segment (210), and the fourth arc segment (220) passes through the starting point of the first straight line segment (120), and the intersection point is located between the starting point and the end point of the fourth arc segment (220).

13. The pole piece cutting method according to claim 11, characterized in that: The second trajectory (200) further comprises a second straight line segment (230), the second straight line segment (230) being connected between the third circular arc segment (210) and the fourth circular arc segment (220), and the second straight line segment (230) is overlapped with or misaligned with the first straight line segment (120).

14. The pole piece cutting method according to any one of claims 11 to 13, characterized in that: The first arc segment (110) and the second arc segment (130) have opposite bending directions, and the first arc segment (110) and the second arc segment (130) are used to cut the top angle of one pole piece (1) and the bottom angle of another pole piece (1) in adjacent pole pieces (1); The third arc segment (210) and the fourth arc segment (220) have opposite bending directions, and the third arc segment (210) and the fourth arc segment (220) are used to cut the bottom angle of one pole piece (1) and the top angle of another pole piece (1) in adjacent pole pieces (1).

15. The pole piece cutting method according to any one of claims 11 to 13, characterized in that: The first arc segment (110) and the second arc segment (130) have the same bending direction, and the first arc segment (110) and the second arc segment (130) are used to cut the top angle and the bottom angle of one of the adjacent pole pieces (1); The third arc segment (210) and the fourth arc segment (220) have the same bending direction, and the third arc segment (210) and the fourth arc segment (220) are used to cut the bottom angle and top angle of another pole piece (1) in the adjacent pole pieces (1).

16. The pole piece cutting method according to any one of claims 11 to 13, characterized in that: The missing corner structures (3) cut out by the first arc segment (110), the second arc segment (130), the third arc segment (210) and the fourth arc segment (220) are of the same type, and the missing corner structures (3) include the first missing corner structure (R) and the second missing corner structure (r).

17. The pole piece cutting method according to any one of claims 11 to 13, characterized in that: The first circular arc segment (110) and the second circular arc segment (130) are suitable for cutting a first missing corner structure (R), and the third circular arc segment (210) and the fourth circular arc segment (220) are suitable for cutting a second missing corner structure (r).

18. The pole piece cutting method according to any one of claims 11 to 13, characterized in that: The missing corner structures (3) cut by the first arc segment (110) and the fourth arc segment (220) are of the same type, the missing corner structures (3) cut by the second arc segment (130) and the third arc segment (210) are of the same type, and the missing corner structures (3) cut by the first arc segment (110) and the second arc segment (130) are of different types, wherein the types of the missing corner structures (3) include the first missing corner structure (R) and the second missing corner structure (r).

19. The pole piece cutting method according to any one of claims 11 to 13, characterized in that: The missing corner structures (3) cut by the first arc segment (110) and the third arc segment (210) are of the same type, the missing corner structures (3) cut by the second arc segment (130) and the fourth arc segment (220) are of the same type, and the missing corner structures (3) cut by the first arc segment (110) and the second arc segment (130) are of different types, wherein the types of the missing corner structures (3) include the first missing corner structure (R) and the second missing corner structure (r).

20. The pole piece cutting method according to claim 10, characterized in that: A cutting slit is provided on the cutting table, and adjacent pole pieces (1) are cut at the cutting slit, wherein an arc structure is provided at the edge of the cutting slit, and an adsorption mechanism and a dust removal mechanism are provided below the cutting slit.

21. The pole piece cutting method according to claim 11, characterized in that: The pole piece cutting method further comprises: Step S3: after reciprocatingly executing step S1 and step S2 and cutting a preset number of first pole pieces (13), the cutting chamfer types of the first arc segment (110), the second arc segment (130), the third arc segment (210) and the fourth arc segment (220) are changed to obtain a third trajectory (300) and a fourth trajectory (400); Step S4: the cutting mechanism cuts the third track (300) along the third direction of the width of the material strip, the third track (300) cuts one of the top corners and one of the bottom corners, and cuts off adjacent pole pieces (1); Step S5: the cutting mechanism cuts the fourth track (400) along a fourth direction of the width of the material strip, and the fourth track (400) cuts another top corner and another bottom corner; Step S6: reciprocatingly executing step S4 and step S5 and cutting a preset number of second pole pieces (14), The change of the cutting chamfer type includes changing the first notch structure (R) to the second notch structure (r), or changing the second notch structure (r) to the first notch structure (R). The third direction is opposite to the fourth direction, The third direction is the same as the first direction, or the third direction is the same as the second direction.

22. The pole piece cutting method according to claim 21, characterized in that: The step S4 is performed before the step S5, or the step S5 is performed before the step S4.

23. A battery, characterized in that: The invention comprises a shell and a laminated battery core arranged in the shell, wherein the laminated battery core is the laminated battery core according to any one of claims 1 to 9.

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