Pole piece and production method thereof, laminated battery cell and production method thereof

Abstract

The present invention relates to a pole piece and a production method thereof, a laminated battery cell and a production method thereof, wherein a pole piece production method comprises the following steps: providing a foil material, setting a curved coating track on the surface of the foil material; coating along the curved coating track to form a coating area, so that a plurality of blank areas are respectively provided on both sides of the foil material in a first direction, and the plurality of blank areas are spaced apart along a second direction to obtain a substrate; die-cutting a portion of the coating area and a portion of the blank area of ​​the substrate material to form a pole piece mold; cutting the pole piece mold material to form a plurality of pole pieces, wherein two adjacent corners of the pole piece are respectively formed with a tab blank area and a first avoidance gap. The present invention can continuously coat a substrate with blank areas on both sides of the first direction by setting a curved coating track, and use an external cutting device to remove a portion of the coating area and the blank area and then cut to form a plurality of pole pieces with the positions of the two adjacent corners of the rectangular pole piece as the tab blank area and the first avoidance gap, thereby achieving high production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of battery production technology, and in particular to a pole piece and a production method thereof, a laminated battery cell and a production method thereof. Background Art

[0002] The current lithium battery manufacturing and production industry involves many complex processes throughout the entire battery production process. The electrode manufacturing process involves stirring, coating, rolling, slitting, and die-cutting, with the dried electrode used to make the battery cell.

[0003] In the existing laminated battery electrode preparation process, a blank area and a coating area are arranged side by side on the electrode die formed by coating and punching. Part of the blank area needs to be die-cut to form the electrode ear. Figure 1 As shown, the electrode substrate needs to be die-cut to remove the blank areas S3 and S4, leaving blank area S2 as the tab. The existing technology has the following technical drawbacks: because the electrode substrate is formed by removing the blank areas S3 and S4, the electrode coating occupies a small area, which affects the energy density of the battery. Summary of the Invention

[0004] The first purpose of the embodiment of the present invention is to provide a method for producing a pole piece, which is simple to operate and can effectively improve the production efficiency of the pole piece;

[0005] A second object of the embodiment of the present invention is to provide a pole piece with a simple structure, a wide coating area, and a high energy density;

[0006] The third object of the embodiment of the present invention is to provide a method for producing a laminated battery cell, which is simple to operate and convenient to produce;

[0007] A fourth object of the embodiments of the present invention is to provide a laminated battery cell with a simple structure and high energy density.

[0008] To achieve this purpose, the embodiment of the present invention adopts the following technical solutions:

[0009] In a first aspect, a method for producing a pole piece is provided, comprising the following steps:

[0010] Step S1, providing a foil material, and setting a curved coating trajectory on the surface of the foil material;

[0011] Step S2, coating along the curved coating trajectory to form a coating area, so that a plurality of blank areas are respectively provided on both sides of the foil in a first direction, and the plurality of blank areas are spaced apart along a second direction, to obtain a substrate, wherein the first direction is the width direction of the foil and the second direction is the length direction of the foil;

[0012] Step S3, die-cutting part of the coating area and part of the blank area of ​​the substrate to form a pole piece mold;

[0013] Step S4: cutting the electrode mold to form a plurality of electrode sheets, wherein two adjacent corners of the electrode sheets along the first direction are respectively formed with a tab blank area and a first avoidance gap.

[0014] As a preferred solution for the production method of the electrode, step S2 specifically includes the following steps:

[0015] Step S21, coating along the third direction for a first distance to form a first coating area, coating along the second direction for a second distance to form a second coating area, coating along the fourth direction for a first distance to form a third coating area, and coating along the second direction for a second distance to form a fourth coating area, wherein the angle between the third direction and the second direction is a first angle α1, the angle between the fourth direction and the second direction is a second angle α2, α1+α2=180°, and both α1 and α2 are not equal to 90°;

[0016] Step S22: repeat step S21 until the foil is completely coated.

[0017] As a preferred solution for the production method of the electrode, step S21 specifically includes the following steps:

[0018] S211, moving a coating nozzle to be positioned above the foil, and continuously moving the foil in the second direction; moving the coating nozzle along one side of the first direction for a first time, so that the foil forms the first coating area with the first distance;

[0019] S212, the coating nozzle remains stationary and continues to move for a second time, so that the foil forms the second coating area with the second distance length;

[0020] S213, moving the coating nozzle along the other side of the first direction for a first time, so that the foil forms the third coating area with the first distance length;

[0021] S214, the coating nozzle remains stationary and continues to move for a second time, so that the foil forms the fourth coating area with the second distance length, wherein the foil and the coating nozzle move at a uniform speed throughout the whole process.

[0022] As a preferred solution for the production method of the electrode, the size of the coating nozzle in the first direction is smaller than the size of the foil. In step S211, in the initial stage, one end of the coating nozzle along the first direction is aligned with one side of the foil along the first direction, and the coating nozzle moves along the first direction until the other end of the coating nozzle along the first direction is aligned with the other side of the foil along the first direction, so that the foil forms the first coating area.

[0023] As a preferred solution for the production method of the electrode, in step S2, the blank area includes multiple first blank areas and multiple second blank areas, multiple first blank areas are arranged at intervals along the second direction on one side of the first direction of the foil, and multiple second blank areas are arranged at intervals on the other side of the first direction of the foil, wherein the first blank area and the second blank area are staggered.

[0024] In the second aspect, a pole piece is provided, which is produced by the above-mentioned pole piece production method, and the pole piece includes: a rectangular foil, on which a tab blank area and a coating area are provided, one of two adjacent corners of the foil is provided with the tab blank area, and the other of two adjacent corners of the foil is symmetrically provided with a first avoidance gap relative to the tab blank area, and the rest of the foil except the tab blank area is the coating area, and an active material layer is provided on the coating area.

[0025] As a preferred solution for the electrode piece, one side surface of the peripheral side surface of the active material layer facing the blank area of ​​the electrode tab is a curved surface, and the first avoidance gap is an arc-shaped gap.

[0026] In a third aspect, a method for producing a laminated battery cell is provided, comprising the following steps:

[0027] S10, obtaining a plurality of electrode sheets produced by the above-mentioned electrode sheet production method, wherein the electrode sheets include positive electrode sheets and negative electrode sheets;

[0028] S20, providing a separator, wherein second avoidance gaps are respectively formed at positions of the separator corresponding to the tab blank areas of the positive electrode sheet and / or the negative electrode sheet and the first avoidance gaps;

[0029] S30. Align the positive electrode sheet, the separator, and the negative electrode sheet in order and stack them in sequence to form a laminated battery cell, wherein the tab blank areas of all the positive electrode sheets are located at one end of the laminated battery cell, and the tab blank areas of all the negative electrode sheets are located at the other end of the laminated battery cell, and the tab blank areas of the positive electrode sheet, the second avoidance gap, and the first avoidance gap of the negative electrode sheet correspond to each other one by one.

[0030] As a preferred solution for the production method of laminated battery cells, step S30 specifically includes the following steps:

[0031] S301, pasting a plurality of positive electrode sheets at intervals on a first side surface of the separator, and pasting a plurality of negative electrode sheets at intervals on a second side surface of the separator, until the separator is completely pasted along its length, wherein the first side surface and the second side surface are arranged opposite to each other;

[0032] S302, setting folding lines on both sides of the separator relative to the positive electrode sheet or the negative electrode sheet along the length direction of the separator, and stacking the layers in sequence along the folding lines to form the laminated battery core.

[0033] In a fourth aspect, a laminated battery cell is provided, which is produced by the laminated battery cell production method as described above, wherein the laminated battery cell includes: a positive electrode sheet, a negative electrode sheet and a separator, wherein a plurality of the positive electrode sheets and a plurality of the negative electrode sheets are cross-stacked, and the separator is arranged between adjacent positive electrode sheets and negative electrode sheets.

[0034] The beneficial effects of the present invention are:

[0035] By setting a curved coating trajectory, a substrate with blank areas on both sides of the first direction is continuously coated to form a substrate, and an external cutting device is used to remove part of the coating area and the blank area and then cut to form multiple rectangular pole pieces with two adjacent corners as the pole ear blank area and the first avoidance gap. The production efficiency is high, and the pole pieces produced by this method only have two adjacent corners as the pole ear blank area and the first avoidance gap. The first avoidance gap of the pole piece is used to avoid the pole ear blank area of ​​another pole piece, which effectively reduces the area of ​​the entire rectangular sheet occupied by the pole ear blank area, so that the remaining part of the rectangular sheet can be fully coated with the active material layer, so that the proportion of the active material layer in the pole piece of the present invention relative to the entire rectangular sheet under the same area is much larger than that of the prior art, thereby effectively improving the energy density of the battery cell; by directly using the pole ear blank area as the pole ear of the pole piece, the overall current flow capacity of the pole piece is avoided from being affected by the limited width of the pole ear, thereby effectively reducing the self-heating phenomenon of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0037] Figure 1 Schematic diagram of the structure of the pole piece of the prior art embodiment.

[0038] Figure 2 Schematic diagram of the structure of the pole piece of an embodiment of the present invention.

[0039] Figure 3 This is a flow chart of a method for producing a pole piece according to an embodiment of the present invention.

[0040] Figure 4 Schematic diagram of the structure of the foil according to an embodiment of the present invention.

[0041] Figure 5 Schematic diagram of the structure of a substrate according to an embodiment of the present invention.

[0042] Figure 6 Schematic diagram of the structure of the diaphragm according to an embodiment of the present invention.

[0043] In the picture:

[0044] 1. Foil; 2. Base material; 21. Curved coating trajectory; 22. Blank area; 221. First blank area; 2211. Second coating blank area; 2212. Third coating blank area; 222. Second blank area; 2221. First coating blank area; 23. Coating area; 231. First coating area; 2311. First sub-coating area; 2312. Second sub-coating area; 232. Second coating area; 233. Third coating area; 234. Fourth coating area; 24. First pre-cut; 25. Second pre-cut; 3. Pole piece mold; 4. Pole piece; 41. Tab blank area; 42. First avoidance gap; 5. Diaphragm; 51. Second avoidance gap; 52. Folding line. DETAILED DESCRIPTION

[0045] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention more clearly understood, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work shall fall within the scope of protection of the present invention.

[0046] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0047] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0048] The present invention provides a pole piece, such as Figure 2 As shown, the electrode piece 4 includes a rectangular foil 1, on which a tab blank area 41 and a coating area 23 are provided. One of the two adjacent corners of the foil 1 is provided with the tab blank area 41, and the other of the two adjacent corners of the foil 1 is symmetrically provided with a first avoidance gap 42 relative to the tab blank area 41. Except for the tab blank area 41, the rest of the foil 1 is the coating area 23, and the coating area 23 is provided with an active material layer. In this embodiment, by directly utilizing the tab blank area 41 at the corner of the rectangular foil 1 as the tab, the space waste of the blank area on both sides of the tab is avoided, so that the coating area of ​​the pole piece 4 for coating the active material layer is wider, thereby effectively improving the energy density of the pole piece 4, and the tab of the pole piece 4 and the foil 1 coated with the active material layer are an integral structure, which effectively ensures the current flow capacity of the tab, avoids affecting the current flow capacity of the tab due to the width limitation of the tab extending out of the foil 1 coated with the active material layer, thereby effectively reducing the self-heating of the pole piece 4 during use.

[0049] Alternatively, as Figure 2 As shown, one side surface of the peripheral side surface of the active material layer facing the tab blank area 41 is a curved surface, and the first avoidance gap 42 is an arc-shaped gap.

[0050] The production of the above-mentioned electrode 4 can be achieved by coating the surface of the foil 1 with an active material layer, and then laser cleaning the two adjacent corners of the foil 1 to form a blank area 41 for the electrode tab and cutting out an avoidance gap. This requires a lot of equipment, complex processing procedures, and low production efficiency.

[0051] In order to solve the above problems, Figure 3 、 Figure 4 and Figure 5 As shown, the present invention provides a method for producing a pole piece 4, comprising the following steps:

[0052] Step S1, providing a foil 1, and setting a curved coating track 21 on the surface of the foil 1;

[0053] Step S2: coating is performed along the curved coating track 21 to form a coating area 23, so that a plurality of blank areas 22 are respectively provided on both sides of the first direction of the foil 1 (the first direction is Figure 4 Y direction), and a plurality of blank areas 22 are arranged at intervals along the second direction (the second direction is Figure 4 The Y direction is the width direction of the foil 1 and the X direction is the length direction of the foil 1 to obtain a substrate 2;

[0054] Specifically, the blank area 22 includes a plurality of first blank areas 221 and a plurality of second blank areas 222. The plurality of first blank areas 221 are spaced apart along the X direction on one side of the foil 1 in the Y direction, and the plurality of second blank areas 222 are spaced apart along the X direction on the other side of the foil 1 in the Y direction. The first blank areas 221 and the second blank areas 222 are staggered.

[0055] Step S3, die-cutting part of the coating area 23 and part of the blank area 22 of the substrate 2 to form a pole piece mold 3;

[0056] Step S4 , cutting the electrode mold 3 to form a plurality of electrode pieces 4 , wherein two adjacent corners of the electrode pieces 4 along the Y direction are respectively formed with a tab blank area 41 and a first avoidance gap 42 .

[0057] This design can continuously coat a substrate 2 with blank areas on both sides of the Y direction by setting a curved coating trajectory 21. By using an external cutting device to remove part of the coating area 23 and the blank area and then cutting, a plurality of rectangular pole pieces 4 can be formed, each of which has two adjacent corners, namely the tab blank area 41 and the first avoidance gap 42. This reduces the laser cleaning step and only requires one cutting process, resulting in high production efficiency, reduced investment in laser cleaning equipment, and reduced production costs. The pole piece 4 produced by this method has only two adjacent corners, namely the tab blank area 41 and the first avoidance gap 42. The first avoidance gap 42 of the pole piece 4 is used to avoid the tab blank area 41 of another pole piece 4, effectively reducing the area of ​​the entire rectangular sheet occupied by the tab blank area 41, so that the remaining part of the rectangular sheet can be fully coated with the active material layer, so that the proportion of the active material layer in the pole piece 4 of the present invention relative to the entire rectangular sheet under the same area is much greater than that of the prior art, thereby effectively improving the energy density of the battery cell. By directly using the tab blank area 41 as the tab of the electrode 4, the overall current flow capacity of the electrode 4 is not affected by the limited width of the tab, thereby effectively reducing the self-heating of the battery cell.

[0058] It is understandable that if Figure 1 and Figure 2As shown, for a rectangular sheet of the same area S1, the structure of the electrode 4 in the prior art is to die-cut and remove the spaced blank areas S3 and S4, leaving the blank area S2 as the electrode ear, and the remaining part is the coating area 23, and the blank area S4 at least includes a blank area S2' corresponding to the blank area S2 as the electrode ear placement position for the next electrode 4, and similarly, there will be S3' on the side of S2' close to the edge of the foil 1, and the electrode ears of two adjacent electrode sheets 4 are spaced apart, and the spacing area is S5, so the blank area S4 can be described as including the blank area S2', the blank area S3' and the blank area S5, the area of ​​the coating area 23 of the electrode 4 in the prior art = S1-S2-S3-S5-S2'-S3', and S2 = S2', S3 = S3', then the area of ​​the coating area 23 of the electrode 4 in the prior art = S1-2S2-2S3-S5. The area of ​​the tab blank area 41 and the first avoidance opening of the electrode 4 of the present application is S6. Therefore, the area of ​​the coating area 23 of the electrode 4 of the present application = S1-2S6. Assuming S6=S2, the present application has an additional coating area 23 of 2S3+S5 areas compared to the prior art to coat the active material layer. In the present application, the tab blank area 41 and the first avoidance opening are arc structures with a radius of R, and the blank area S2 is a rectangular structure with a side length of R. S6 is much smaller than S2, which reflects that the electrode 4 of the present application occupies a larger coating area than the electrode 4 of the prior art, so that the active material layer of the electrode 4 occupies a wider area, thereby improving the energy density of the battery cell.

[0059] In an alternative embodiment, if Figure 4 As shown, step S2 specifically includes the following steps:

[0060] Step S21: coating a first distance L1 along a third direction to form a first coating area 231 (the third direction is Figure 4 A direction in the middle), a second distance L2 is coated along the Y direction to form a second coating area 232, and a first distance L1 is coated along the fourth direction to form a third coating area 233 (the fourth direction is Figure 4 A second distance L2 is applied along the Y direction to form a fourth coating area 234, wherein the angle between the A direction and the X direction is a first angle α1, the angle between the B direction and the X direction is a second angle α2, α1+α2=180°, and both α1 and α2 are not equal to 90°;

[0061] Step S22: repeat step S21 until the foil 1 is completely coated in the X direction.

[0062] Specifically, step S21 includes the following steps:

[0063] S211, moving the coating nozzle above the foil 1, and continuously moving the foil 1 along the X direction; moving the coating nozzle to one side along the Y direction for a first time, so that the foil 1 forms a first coating area 231 with a first distance L1;

[0064] For example, the size of the coating nozzle in the Y direction is smaller than the size of the foil 1. In step S211, at the initial stage, one end of the coating nozzle in the Y direction is aligned with one side of the foil 1 in the Y direction. The coating nozzle moves in the Y direction until the other end of the coating nozzle in the Y direction is aligned with the other side of the foil 1 in the Y direction, so that the foil 1 forms a first coating area 231. This design allows the foil 1 to flow along the X direction, so that the coating nozzle only needs to move in the Y direction to complete the coating. After the foil 1 is coated, it can flow to subsequent baking, die-cutting, slitting and other processes, and the equipment occupies a small space. Of course, in other embodiments, the foil 1 can remain stationary, and the coating nozzle can move in the Y direction and the X direction at the same time, and the coating process of the curved coating trajectory 21 can also be completed.

[0065] S212, the coating nozzle remains stationary and continues to move for a second time, so that the foil 1 forms a second coating area 232 with a second distance L2;

[0066] S213, moving the coating nozzle along the other side of the Y direction for a first time, so that the foil 1 forms a third coating area 233 with a length of the first distance L1; that is, the coating nozzle moves toward the initial end position until the coating nozzle moves to the initial end position;

[0067] S214 , the coating nozzle remains stationary and continues to move for a second time, so that the foil 1 forms a fourth coating area 234 with a second distance L2 , wherein the foil 1 and the coating nozzle move at a uniform speed throughout the entire process.

[0068] Further, if Figure 5 As shown, step S3 specifically includes the following steps:

[0069] S31, dividing the substrate 2 into a plurality of first regions equidistantly along the X direction with the boundary line obtained in step S21, and providing a first pre-cut 24 and a second pre-cut 25 on both sides of the first region in the Y direction, wherein the first pre-cut 24 and the second pre-cut 25 are staggered and stacked;

[0070] S32. Cut the first pre-cuts 24 and second pre-cuts 25 in all first regions one by one to form the electrode sheet mold 3. This design only requires die-cutting to allow the substrate 2 to be spaced apart on both sides of the Y direction to have the tab blank areas 41 and the first avoidance notches 42, allowing for subsequent direct and evenly spaced cutting to form multiple electrode sheets 4, making molding easier.

[0071] Specifically, if Figure 5As shown, in step S31, the blank areas 22 spaced apart on both sides of the first coating area 231 along the Y direction are the first coating blank area 2221 and the second coating blank area 2211, the first coating blank area 2221 is used as the tab blank area 41, the blank area 22 distributed on one side of the second coating area 232 is the third coating blank area 2212, the third coating blank area 2212 is adjacent to the second coating blank area 2211, the critical line between the second coating area 232 and the third coating blank area 2212 is the first boundary, and the area of ​​the first coating area 231 protruding from the first boundary is the first sub-coating area 23 11. The area where the first sub-coating area 2311 is symmetrically distributed about the first boundary is the second sub-coating area 2312. The first sub-coating area 2311, the second sub-coating area 2312, the second coating blank area 2211 and the third coating blank area 2212 are combined to form a first pre-cut 24. The structure of the first pre-cut 24 is symmetrically arranged about the central axis of the substrate 2 along the Y direction to obtain the structure of the second pre-cut 25. It should be noted that the first pre-cut 24 and the second pre-cut 25 are staggered along the X direction. Only structural information such as corresponding shape and size is obtained through symmetry, and position information is not included.

[0072] In other embodiments, the substrate 2 may be coated along the curved coating trajectory 21 and then cut into multiple rectangular structures at equal intervals, and then part of the coating area 23 and the blank area 22 may be removed to obtain the electrode 4, which will not be described in detail here.

[0073] An embodiment of the present invention further provides a method for producing a laminated battery cell, comprising the following steps:

[0074] S10, obtaining a plurality of electrode sheets 4 produced by the above-mentioned method for producing electrode sheets 4, wherein the electrode sheets 4 include a positive electrode sheet 4 and a negative electrode sheet 4;

[0075] S20, such as Figure 6 As shown, a diaphragm 5 is provided, and second avoidance gaps 51 are respectively opened at positions of the diaphragm 5 corresponding to the tab blank areas 41 and the first avoidance gaps 42 of the positive electrode sheet 4 and / or the negative electrode sheet 4;

[0076] S30, aligning a plurality of positive electrode sheets 4, a plurality of separators 5, and a plurality of negative electrode sheets 4 in sequence and stacking them in sequence to form a laminated battery cell, wherein the tab blank area 41 of all positive electrode sheets 4 is located at one end of the laminated battery cell, and the tab blank area 41 of all negative electrode sheets 4 is located at the end of the laminated battery cell opposite to the tab blank area 41 of the positive electrode sheet 4, and the tab blank area 41 of the positive electrode sheet 4, the second avoidance gap 51, and the first avoidance gap 42 of the negative electrode sheet 4 correspond one to one. It can be understood that the tab blank areas 41 of all positive electrode sheets 4 are connected by welding, the positive electrode tab cover is provided on the outer surface of the laminated battery cell, and one end is welded to the tab blank area 41 of the positive electrode sheet 4, the tab blank areas 41 of all negative electrode sheets 4 are connected by welding, and the negative electrode tab cover is provided on the outer surface of the laminated battery cell, and one end is welded to the tab blank area 41 of the negative electrode sheet 4. The laminated battery cell of the present invention is formed by stacking the positive electrode sheet 4 and the negative electrode sheet 4 obtained by the production method of the electrode sheet 4 provided by any of the above embodiments. The blank area 41 of the pole ear of the pole sheet 4 is located in the rectangular foil 1, reducing the phenomenon of the pole ear being exposed from the rectangular foil 1. By using the corners of the rectangular foil 1 itself as the blank area 22 for connecting the pole sheets 4, the current flow capacity of the connection between the pole sheets 4 is increased, the internal resistance of the laminated battery cell is effectively reduced, the charging and discharging efficiency of the laminated battery cell is improved, and the heat generated during the charging and discharging process of the laminated battery cell can be effectively reduced, thereby ensuring the stability of the laminated battery cell.

[0077] Optionally, step S30 specifically includes the following steps:

[0078] S301, affixing a plurality of positive electrode sheets 4 to a first side surface of the separator 5 at intervals, and affixing a plurality of negative electrode sheets 4 to a second side surface of the separator 5 at intervals, until the separator 5 is completely affixed along its length, wherein the first side surface and the second side surface are arranged opposite to each other;

[0079] S302 , setting folding lines 52 on both sides of the separator 5 along the length direction of the separator 5 relative to the positive electrode sheet 4 or the negative electrode sheet 4 , and stacking the layers in sequence along the folding lines 52 to form a laminated battery cell.

[0080] For example, Figure 6 As shown, a plurality of positive electrode sheets 4 are pasted on the first side of the diaphragm 5 at intervals of one electrode sheet 4 width, and a plurality of negative electrode sheets 4 are pasted on the second side of the diaphragm 5 at intervals of one electrode sheet 4 width. The positive electrode sheets 4 and the negative electrode sheets 4 overlap, and are folded along the length direction of the diaphragm 5 at intervals of one electrode sheet 4 width to form a battery cell. There is a negative electrode sheet 4 between two adjacent positive electrode sheets 4, and there is a diaphragm 5 between adjacent positive electrode sheets 4 and negative electrode sheets 4. This design method does not require cutting the diaphragm 5 into the size of the electrode sheet 4 one by one and then pasting them one by one, which effectively improves the production efficiency of the laminated battery cell.

[0081] An embodiment of the present invention further provides a laminated battery cell, prepared by the laminated battery cell production method described above, comprising: a positive electrode sheet 4, a negative electrode sheet 4, and a separator 5. Multiple positive electrode sheets 4 and multiple negative electrode sheets 4 are cross-stacked along the length direction, and a separator 5 is provided between adjacent positive electrode sheets 4 and negative electrode sheets 4. The positive and negative electrode sheets 4 of the laminated battery cell use their own rectangular corners as tab blank areas 41 for connection between the electrode sheets 4. This reduces the exposure of the tabs to the rectangular foil 1, increases the current flow capacity of the connection between the electrode sheets 4, effectively reduces the internal resistance of the laminated battery cell, improves the charging and discharging efficiency of the laminated battery cell, effectively reduces heat generation during the charging and discharging process of the laminated battery cell, and maintains the stability of the laminated battery cell.

[0082] In the description of this article, it should be understood that the terms "upper", "lower", etc., and the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present invention.

[0083] In the description of this specification, the description of reference terms such as "an embodiment" means that the specific features, structures, materials, or characteristics of the embodiment are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment.

[0084] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0085] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.

Claims

1. A method for producing a pole piece, characterized in that: The following steps are involved: Step S1, providing a foil material, and setting a curved coating trajectory on the surface of the foil material; Step S2, coating along the curved coating trajectory to form a coating area, so that a plurality of blank areas are respectively provided on both sides of the first direction of the foil, and the plurality of blank areas are arranged at intervals along the second direction, to obtain a substrate, the blank areas including a plurality of first blank areas and a plurality of second blank areas, the plurality of first blank areas are arranged at intervals along the second direction on one side of the first direction of the foil, and the plurality of second blank areas are arranged at intervals along the second direction on the other side of the first direction of the foil, wherein the first blank areas and the second blank areas are staggered, the first direction is the width direction of the foil, and the second direction is the length direction of the foil; The coating specifically comprises the following steps: Step S21: coating along the third direction for a first distance to form a first coating area, coating along the second direction for a second distance to form a second coating area, coating along the fourth direction for a first distance to form a third coating area, and coating along the second direction for a second distance to form a fourth coating area, wherein the angle between the third direction and the second direction is a first angle α1, the angle between the fourth direction and the second direction is a second angle α2, α1+α2=180°, and both α1 and α2 are not equal to 90°; Step S22, repeating step S21 until the foil is completely coated; Step S3, die-cutting part of the coating area and part of the blank area of ​​the substrate to form a pole piece mold; Step S4: cutting the electrode mold to form a plurality of electrode sheets, wherein two adjacent corners of the electrode sheets along the first direction are respectively formed with a tab blank area and a first avoidance gap.

2. The method for producing a pole piece according to claim 1, characterized in that: Step S21 specifically includes the following steps: S211, moving a coating nozzle to be positioned above the foil, and continuously moving the foil in the second direction; moving the coating nozzle along one side of the first direction for a first time, so that the foil forms the first coating area with the first distance; S212, the coating nozzle remains stationary and continues to move for a second time, so that the foil forms the second coating area with the second distance length; S213, moving the coating nozzle along the other side of the first direction for a first time, so that the foil forms the third coating area with the first distance length; S214, the coating nozzle remains stationary and continues to move for a second time, so that the foil forms the fourth coating area with the second distance length, wherein the foil and the coating nozzle move at a uniform speed throughout the whole process.

3. The method for producing a pole piece according to claim 2, characterized in that: In the first direction, the size of the coating nozzle is smaller than the size of the foil. In step S211, in the initial stage, one end of the coating nozzle along the first direction is aligned with one side of the foil along the first direction, and the coating nozzle moves along the first direction until the other end of the coating nozzle along the first direction is aligned with the other side of the foil along the first direction, so that the foil forms the first coating area.

4. A pole piece, characterized in that: The electrode is produced by the production method of any one of claims 1 to 3, and the electrode comprises: a rectangular foil, on which a tab blank area and a coating area are provided, one of two adjacent corners of the foil is provided with the tab blank area, and the other of two adjacent corners of the foil is symmetrically provided with a first avoidance gap relative to the tab blank area, and the rest of the foil except the tab blank area is the coating area, and an active material layer is provided on the coating area.

5. The pole piece according to claim 4, characterized in that: One side surface of the peripheral side surface of the active material layer facing the tab blank area is a curved surface, and the first avoidance gap is an arc-shaped gap.

6. A method for producing a laminated battery cell, characterized in that: The following steps are involved: S10, obtaining a plurality of electrode sheets produced by the electrode sheet production method according to any one of claims 1 to 3, wherein the electrode sheets include positive electrode sheets and negative electrode sheets; S20, providing a separator, wherein second avoidance gaps are respectively formed at positions of the separator corresponding to the tab blank areas of the positive electrode sheet and / or the negative electrode sheet and the first avoidance gaps; S30. Align the positive electrode sheet, the separator, and the negative electrode sheet in order and stack them in sequence to form a laminated battery cell, wherein the tab blank areas of all the positive electrode sheets are located at one end of the laminated battery cell, and the tab blank areas of all the negative electrode sheets are located at the other end of the laminated battery cell, and the tab blank areas of the positive electrode sheet, the second avoidance gap, and the first avoidance gap of the negative electrode sheet correspond to each other one by one.

7. The method for producing a laminated battery core according to claim 6, characterized in that: Step S30 specifically includes the following steps: S301, pasting a plurality of positive electrode sheets at intervals on a first side surface of the separator, and pasting a plurality of negative electrode sheets at intervals on a second side surface of the separator, until the separator is completely pasted along its length, wherein the first side surface and the second side surface are arranged opposite to each other; S302, setting folding lines on both sides of the separator relative to the positive electrode sheet or the negative electrode sheet along the length direction of the separator, and stacking the layers in sequence along the folding lines to form the laminated battery core.

8. A laminated battery cell, characterized in that: The laminated battery cell is produced by the production method of the laminated battery cell as described in claim 6 or 7, and the laminated battery cell includes: a positive electrode sheet, a negative electrode sheet and a separator, a plurality of the positive electrode sheets and a plurality of the negative electrode sheets are cross-stacked, and the separator is arranged between adjacent positive electrode sheets and negative electrode sheets.

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