Pole piece group, laminated battery cell and battery

Abstract

The utility model relates to the technical field of batteries, and discloses a pole piece group, a laminated cell and a battery, the pole piece group comprises a first pole piece and a second pole piece with the same polarity, unfilled corner structures are arranged at the corners of the first pole piece and the second pole piece, the first pole piece is provided with one of the first unfilled corner structure and the second unfilled corner structure at the same corner position, and the second pole piece is provided with one of the second unfilled corner structure and the first unfilled corner structure. The first pole piece is provided with one of a first unfilled corner structure and a second unfilled corner structure, the second pole piece is provided with the other one of the first unfilled corner structure and the second unfilled corner structure, and the size of the first unfilled corner structure is larger than that of the second unfilled corner structure, so that the second unfilled corner structure protrudes out of the first unfilled corner structure when the first pole piece and the second pole piece are laminated. When the pole piece and the diaphragm are overlapped, the second unfilled corner structure protrudes out of the first unfilled corner structure along the thickness direction of the battery cell, and the hollow area exists at the same corner position, so that the hollow area can buffer and reduce pressure in a hot pressing process, and the pressure is prevented from being transmitted layer by layer along with the pole piece; and the risk that burrs at the corners of the pole piece pierce the diaphragm in the hot pressing process is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a pole piece group, a laminated battery core and a battery. Background Art

[0002] A laminated battery cell is a battery cell formed by stacking a predetermined number of layers of positive electrode sheets, diaphragms, and negative electrode sheets in sequence. The electrode sheets are usually cut from strips, and after cutting, burrs will form on the four corners of the electrode sheets. In the subsequent lamination process, the laminated battery cell usually needs to be hot-pressed. Since there are electrode sheets on both sides of the diaphragm, during the hot-pressing process, the pressure is transmitted layer by layer along the thickness direction of the battery cell along with the electrode sheets, so that the burrs have the risk of piercing the diaphragm, causing the battery to short-circuit and become scrapped. Utility Model Content

[0003] In view of this, the utility model provides a pole piece group, a laminated battery cell and a battery to solve the problem in the prior art that the burrs on the pole piece corners are easy to pierce the diaphragm during hot pressing of the laminated battery cell.

[0004] In order to solve the above problems, the utility model provides a pole piece group, including: a first pole piece and a second pole piece of the same polarity, wherein the first pole piece and the second pole piece are provided with a missing corner structure at the corners, and located at the same corner, the first pole piece is provided with one of the first missing corner structure and the second missing corner structure, and the second pole piece is provided with the other of the first missing corner structure and the second missing corner structure, wherein the size of the first missing corner structure is larger than the size of the second missing corner structure, so that when the first pole piece and the second pole piece are stacked, the second missing corner structure protrudes from the first missing corner structure.

[0005] Optionally, the first pole piece and the second pole piece are both positive pole pieces; or, the first pole piece and the second pole piece are both negative pole pieces.

[0006] Optionally, the first pole piece and the second pole piece both include a first top angle, a second top angle, a first bottom angle and a second bottom angle, the first bottom angle and the first top angle are located on the same side, and the second bottom angle and the second top angle are located on the same side, wherein: the first top angle includes a first missing angle structure or a second missing angle structure; and / or, the second top angle includes a first missing angle structure or a second missing angle structure; and / or, the first bottom angle includes a first missing angle structure or a second missing angle structure; and / or, the second bottom angle includes a first missing angle structure or a second missing angle structure.

[0007] Optionally, the first top angle and the second bottom angle of the first pole piece include the first missing angle structure, and the second top angle and the first bottom angle of the first pole piece include the second missing angle structure; the second top angle and the first bottom angle of the second pole piece include the first missing angle structure, and the first top angle and the second bottom angle of the second pole piece include the second missing angle structure.

[0008] Optionally, the first top corner and the second top corner of the first pole piece include the first missing corner structure, and the first bottom corner and the second bottom corner of the first pole piece include the second missing corner structure; the first bottom corner and the second bottom corner of the second pole piece include the first missing corner structure, and the first top corner and the second top corner of the second pole piece include the second missing corner structure.

[0009] Optionally, the first top angle and the first bottom angle of the first pole piece include the first missing angle structure, and the second top angle and the second bottom angle of the first pole piece include the second missing angle structure; the second top angle and the second bottom angle of the second pole piece include the first missing angle structure, and the first top angle and the first bottom angle of the second pole piece include the second missing angle structure.

[0010] Optionally, the first top angle, the second top angle, the first bottom angle and the second bottom angle of the first pole piece all include the first missing-angle structure; the first top angle, the second top angle, the first bottom angle and the second bottom angle of the second pole piece all include the second missing-angle structure.

[0011] Optionally, the missing corner structure includes a beveled corner or a rounded corner.

[0012] Optionally, the notch structure includes rounded corners, a radius of the first notch structure is in a range of 1 mm to 5 mm, and a radius of the second notch structure is in a range of 0.2 mm to 2 mm.

[0013] The utility model also provides a laminated battery core, comprising the above-mentioned electrode group, the electrode group comprising a first electrode group and a second electrode group, the first electrode group comprising a first positive electrode sheet and a second positive electrode sheet, the second electrode group comprising a first negative electrode sheet and a second negative electrode sheet; the laminated battery core comprises electrode sheets and a diaphragm stacked in sequence, the electrode sheets comprising a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and the negative electrode sheet are stacked in sequence; the types of two adjacent positive electrode sheets are different, and the types of positive electrode sheets include a first positive electrode sheet and a second positive electrode sheet; the types of two adjacent negative electrode sheets are different, and the types of negative electrode sheets include a first negative electrode sheet and a second negative electrode sheet.

[0014] The utility model also provides a battery, characterized in that it comprises a shell and a laminated battery core arranged in the shell, and the laminated battery core is the laminated battery core mentioned above.

[0015] The utility model has the following advantages:

[0016] By utilizing the technical solution of the present invention, by setting the same corner position of the first pole piece and the second pole piece of the same polarity to different sizes, that is, one of the pole pieces is provided with a first corner-cut structure, and the other pole piece is provided with a second corner-cut structure, when the pole piece and the diaphragm are stacked, along the thickness direction of the battery cell, the second corner-cut structure protrudes from the first corner-cut structure, and there is a hollow area at the same corner position. In the subsequent hot pressing process, the hollow area can buffer and reduce the pressure, prevent the pressure from being transmitted layer by layer along the pole piece, and reduce the risk of burrs at the corners of the pole piece piercing the diaphragm during the hot pressing process. Therefore, the technical solution of the present invention solves the defect of the prior art that the burrs at the corners of the pole pieces are easy to pierce the diaphragm during hot pressing of stacked battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic cross-sectional view of a laminated battery cell at a corner of a pole piece in the prior art is shown;

[0019] Figure 2 A schematic structural diagram of a first pole piece and a second pole piece of a positive pole piece (first pole piece group) of a laminated battery cell in a first embodiment of the utility model is shown;

[0020] Figure 3 Shows Figure 2 A schematic diagram of the structure after the first pole piece and the second pole piece are stacked;

[0021] Figure 4 Shows Figure 3 The enlarged schematic diagram at A in the middle;

[0022] Figure 5 A schematic structural diagram of a first pole piece and a second pole piece of a negative pole piece (a second pole piece group) of a laminated battery cell in a first embodiment of the utility model is shown;

[0023] Figure 6 Shows Figure 5 A schematic diagram of the structure after the first pole piece and the second pole piece are stacked;

[0024] Figure 7 Shows Figure 6 The enlarged schematic diagram of point B in the middle;

[0025] Figure 8 The schematic diagram of the structure of the laminated battery cell of the utility model is shown;

[0026] Fig. 9 Shows Figure 8 Schematic diagram of CC section;

[0027] Fig.10 A schematic structural diagram of a first pole piece and a second pole piece of a second embodiment of a laminated battery cell of the utility model is shown;

[0028] Fig.11 A schematic structural diagram of a first pole piece and a second pole piece of a third embodiment of a laminated battery cell of the utility model is shown;

[0029] Fig.12 A schematic structural diagram of a first pole piece and a second pole piece of a fourth embodiment of a laminated battery cell of the utility model is shown.

[0030] Description of reference numerals:

[0031] 1', positive electrode; 2', negative electrode; 3', diaphragm;

[0032] 1. Pole piece group; 11. First pole piece group; 12. Second pole piece group; 13. First pole piece; 14. Second pole piece; 101. First top angle; 102. Second top angle; 103. First bottom angle; 104. Second bottom angle; 2. Diaphragm; 3. Notch structure; R. First notch structure; r. Second notch structure. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0034] Combine the following Figures 1 to 12 , describing an embodiment of the utility model.

[0035] According to an embodiment of the utility model, on the one hand, a pole piece group 1 is provided, including: a first pole piece 13 and a second pole piece 14 of the same polarity, and corners of the first pole piece 13 and the second pole piece 14 are provided with a missing corner structure 3, located at the same corner, the first pole piece 13 is provided with one of the first missing corner structure R and the second missing corner structure r, and the second pole piece 14 is provided with the other of the first missing corner structure R and the second missing corner structure r, wherein the size of the first missing corner structure R is larger than the size of the second missing corner structure r, so that when the first pole piece 13 and the second pole piece 14 are stacked, the second missing corner structure r protrudes from the first missing corner structure R.

[0036] By setting the same corner position of the first pole piece 13 and the second pole piece 14 of the same polarity to different sizes, that is, one pole piece is provided with a first corner-cut structure R, and the other pole piece is provided with a second corner-cut structure r, when the pole piece and the diaphragm 2 are stacked, along the thickness direction of the battery cell, the second corner-cut structure r protrudes from the first corner-cut structure R, and there is a hollow area at the same corner position. In the subsequent hot pressing process, the hollow area can buffer and reduce the pressure, prevent the pressure from being transmitted layer by layer along the pole piece, and reduce the risk of burrs at the corners of the pole piece piercing the diaphragm 2 during the hot pressing process.

[0037] It is worth noting that if Figure 1 As shown, along the thickness direction of the battery cell ( Figure 1 There are pole pieces (positive pole piece 1' and negative pole piece 2') on both sides of the diaphragm 3', which means that during the hot pressing process, the pressure is transmitted layer by layer along with the pole pieces, making it very easy for the corner burrs of the positive pole piece 1' to pierce the diaphragm 3'.

[0038] It should be noted that Figure 2 The direction shown is used for explanation, and the corners of the pole piece refer to the position where the top edge and the side edge meet, and the position where the bottom edge and the side edge meet. Therefore, the pole piece has four corner positions. Preferably, the four corner positions of the first pole piece 13 and the second pole piece 14 all satisfy "located at the same corner position, 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".

[0039] The "missing corner structure 3" in this embodiment refers to cutting off a portion of the material at the corners of the pole piece so that the boundary line at the corners of the pole piece 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 are cut to obtain a smoother structure, it is the meaning included in the "missing corner structure 3" in this embodiment.

[0040] Furthermore, in the present 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. Among them, "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. Therefore, in the first pole piece 13 and the second pole piece 14, located at the same corner position, if one of the pole pieces is provided with the first notched corner structure R and the other pole piece is provided with the second notched corner structure r, then after the two pole pieces 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. Furthermore, as Figure 8 and Fig. 9 As shown, at the corners of the pole pieces of the laminated battery cell, the second notch structure r protrudes beyond the first notch structure R to form a hollow area. During the subsequent hot pressing process, the hollow area can buffer and reduce the pressure, thereby reducing the risk of burrs piercing the diaphragm 2.

[0041] In one embodiment, Figure 2 and Figure 5 As shown, the first pole piece 13 and the second pole piece 14 are both positive pole pieces; or, the first pole piece 13 and the second pole piece 14 are both negative pole pieces.

[0042] It should be noted that when the electrode set 1 of this embodiment is used for lamination, the first electrode set 11 and the second electrode set 12 are used simultaneously, wherein the first electrode set 11 are all positive electrode sets, and the second electrode set 12 are all negative electrode sets. Those skilled in the art can understand that the positive electrode sets include two specifications of electrode sets (AB electrode sets), and the negative electrode sets also include two specifications of electrode sets (AB electrode sets). The structural form of the laminated battery cell is "…diaphragm 2-first electrode set 13 of the second electrode set 12-diaphragm 2-first electrode set 13 of the first electrode set 11-diaphragm 2-second electrode set 12 14-diaphragm 2-second electrode set 14 of the first electrode set 11-diaphragm 2…"

[0043] In one embodiment, Figure 2 as well as Figures 10 to 12 As shown, the first pole piece 13 and the second pole piece 14 both 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 located on the same side, and the second bottom corner 104 and the second top corner 102 are located on the same side, wherein: the first top corner 101 includes a first missing corner structure R or a second missing corner structure r; and / or, the second top corner 102 includes the first missing corner structure R or the second missing corner structure r; and / or, the first bottom corner 103 includes the first missing corner structure R or the second missing corner structure r; and / or, the second bottom corner 104 includes the first missing corner structure R or the second missing corner structure r.

[0044] This allows the corners of the first pole piece 13 and the second pole piece 14 to have a variety of combinations, specifically:

[0045] In the first embodiment, if Figure 2 As shown, the first top corner 101 and the second top corner 102 of the first pole piece 13 include a first missing corner structure R, and the first bottom corner 103 and the second bottom corner 104 of the first pole piece 13 include a 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 a second missing corner structure r.

[0046] In the second embodiment, if Fig.10 The first top corner 101 and the second bottom corner 104 of the first pole piece 13 shown include a first missing corner structure R, and the second top corner 102 and the first bottom corner 103 of the first pole piece 13 include a 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 a second missing corner structure r.

[0047] In a third embodiment, if Fig.11 As shown, the first top corner 101 and the first bottom corner 103 of the first pole piece 13 include a first missing corner structure R, and the second top corner 102 and the second bottom corner 104 of the first pole piece 13 include a second missing corner 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 a second missing corner structure r.

[0048] In the fourth embodiment, Fig.12 As shown, the first top corner 101, the second top corner 102, the first bottom corner 103 and the second bottom corner 104 of the first pole piece 13 all include a first missing corner structure R; the first top corner 101, the second top corner 102, the first bottom corner 103 and the second bottom corner 104 of the second pole piece 14 all include a second missing corner structure r.

[0049] Specifically, Figure 2 As shown, the setting methods of each corner can be:

[0050] The first vertex 101 of the first pole piece 13 is set to a first missing corner structure R, and the first vertex 101 of the second pole piece 14 is set to a second missing corner structure r; or the first vertex 101 of the first pole piece 13 is set to the second missing corner structure r, and the first vertex 101 of the second pole piece 14 is set to the first missing corner structure R;

[0051] The second vertex 102 of the first pole piece 13 is set to the first missing corner structure R, and the second vertex 102 of the second pole piece 14 is set to the second missing corner structure r; or the second vertex 102 of the first pole piece 13 is set to the second missing corner structure r, and the second vertex 102 of the second pole piece 14 is set to the first missing corner structure R;

[0052] The first bottom corner 103 of the first pole piece 13 is set to a first missing corner structure R, and the first bottom corner 103 of the second pole piece 14 is set to a second missing corner structure r; or, the first bottom corner 103 of the first pole piece 13 is set to the second missing corner structure r, and the first bottom corner 103 of the second pole piece 14 is set to the first missing corner structure R;

[0053] The second bottom corner 104 of the first pole piece 13 is set as the first missing corner structure R, and the second bottom corner 104 of the second pole piece 14 is set as the second missing corner structure r; or, the second bottom corner 104 of the first pole piece 13 is set as the second missing corner structure r, and the second bottom corner 104 of the second pole piece 14 is set as the first missing corner structure R.

[0054] It is worth noting that both the positive electrode sheet and the negative electrode sheet can be arranged in the above-mentioned corner form.

[0055] In one embodiment, the notched corner structure 3 includes a beveled corner or a rounded corner.

[0056] Further, the notch structure 3 includes rounded corners, the radius of the first notch structure R is in the range of 1 mm to 5 mm, and the radius of the second notch structure r is in the range of 0.2 mm to 2 mm.

[0057] It is worth noting that when the corner-cut structure 3 is rounded and cut by laser, the quality of the first corner-cut structure R is better than that of the second corner-cut structure r. The specific principle is:

[0058] The laser light is a point-shaped spot, and the laser cuts into lines by the overlap of the spots. In the straight cutting section, the laser moves at the fastest speed, but when it encounters a turn, the laser speed will decrease, but the laser light continues to be emitted, and the overlap rate of the spots is very high at this time. Furthermore, the smaller the turning radius, the higher the overlap rate of the laser spots, resulting in more obvious laser energy concentration, which will cause poor cutting quality.

[0059] Therefore, when the notched corner structure 3 is a rounded corner, the radius of the first notched corner structure R is larger than the radius of the second notched corner structure r, that is, the quality of the first notched corner structure R is better than the quality of the second notched corner structure r, which is reflected in the fact that the burr length of the first notched corner structure R is smaller than the burr length of the second notched corner structure r.

[0060] It should be noted that both the first notched corner structure R and the second notched corner structure r are qualified rounded corner structures, but the quality of the first notched corner structure R is better than that of the second notched corner structure r (dominant angle and sub-dominant angle). It cannot be understood that the second notched corner structure r after cutting is an unqualified rounded corner.

[0061] Based on this, Fig. 9 As shown, in fact, in the laminated battery cell of this embodiment, the first notch structure R of the positive electrode sheet will still be subjected to the pressure transmitted by the electrode sheet layer by layer during the hot pressing process, but as mentioned above, the first notch structure R is a dominant angle, the burr length is short and less, and the probability of the burr piercing the diaphragm 2 is low. However, at the second notch structure r of the positive electrode sheet, there is a hollow area below it (that is, the second notch structure r protrudes from the area of ​​the first notch structure R), so although the burrs at the sub-optimal angle are long and more, the hollow area below it can buffer and reduce the pressure, so that the pressure will not be transmitted layer by layer by the electrode sheet, so that the probability of the burr piercing the diaphragm 2 during the hot pressing process is low.

[0062] Furthermore, the negative electrode sheet also has an optimal angle and a suboptimal angle, but as mentioned above, in the case of a "negative-wrapped-positive" structure of the laminated battery cell, there is a hollow area formed by the positive electrode sheet between the negative electrode sheets, so the risk of burrs piercing the diaphragm 2 is not great.

[0063] According to an embodiment of the utility model, on the other hand, a laminated battery cell is also provided, including the above-mentioned electrode group 1, the electrode group 1 includes a first electrode group 11 and a second electrode group 12, the first electrode group 11 includes a first positive electrode sheet and a second positive electrode sheet, and the second electrode group 12 includes a first negative electrode sheet and a second negative electrode sheet; the laminated battery cell includes electrode sheets and a diaphragm 2 stacked in sequence, the electrode sheets include a positive electrode sheet and a negative electrode sheet, and the positive electrode sheet and the negative electrode sheet are stacked in sequence; the types of two adjacent positive electrode sheets are different, and the types of the positive electrode sheets include a first positive electrode sheet and a second positive electrode sheet; the types of two adjacent negative electrode sheets are different, and the types of the negative electrode sheets include a first negative electrode sheet and a second negative electrode sheet.

[0064] It is worth noting that the structure of the laminated battery cell is “…diaphragm 2-first negative electrode sheet-diaphragm 2-first positive electrode sheet-diaphragm 2-second negative electrode sheet-diaphragm 2-second positive electrode sheet-diaphragm 2…”.

[0065] It should be noted that the first positive electrode sheet is the first electrode sheet 13 with positive polarity, and the second positive electrode sheet is the second electrode sheet 14 with positive polarity; the first negative electrode sheet is the first electrode sheet 13 with negative polarity, and the second negative electrode sheet is the second electrode sheet 14 with negative polarity.

[0066] According to an embodiment of the present utility model, on another aspect, a battery is provided, characterized in that it comprises a shell and a laminated battery core arranged in the shell, and the laminated battery core is the laminated battery core mentioned above.

[0067] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A pole piece assembly, characterized in that: include: A first pole piece (13) and a second pole piece (14) of the same polarity, wherein corners of the first pole piece (13) and the second pole piece (14) are provided with a corner-cut structure (3), and the first pole piece (13) and the second pole piece (14) are located at the same corner. 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 the size of the first corner-cut structure (R) is greater than the size of the second corner-cut structure (r), so that when the first pole piece (13) and the second pole piece (14) are stacked, the second corner-cut structure (r) protrudes from the first corner-cut structure (R).

2. The pole piece assembly according to claim 1, characterized in that: The first pole piece (13) and the second pole piece (14) are both positive pole pieces; or the first pole piece (13) and the second pole piece (14) are both negative pole pieces.

3. The pole piece assembly according to claim 1 or 2, 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 vertex (101) includes a first notch structure (R) or a second notch structure (r); and / or, The second vertex (102) includes a first notch structure (R) or a second notch structure (r); and / or, The first bottom corner (103) includes a first notch structure (R) or a second notch structure (r); and / or, The second bottom corner (104) includes a first notch structure (R) or a second notch structure (r).

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

8. The pole piece assembly according to claim 1 or 2, characterized in that: The missing corner structure (3) comprises an oblique corner or a rounded corner.

9. The pole piece assembly according to claim 8, characterized in that: The notch structure (3) comprises rounded corners, the radius of the first notch structure (R) is in the range of 1 mm to 5 mm, and the radius of the second notch structure (r) is in the range of 0.2 mm to 2 mm.

10. A laminated battery cell, characterized in that: A pole piece group (1) comprising any one of claims 1 to 9, wherein the pole piece group (1) comprises a first pole piece group (11) and a second pole piece group (12), wherein the first pole piece group (11) comprises a first positive pole piece and a second positive pole piece, and the second pole piece group (12) comprises a first negative pole piece and a second negative pole piece; The laminated battery core comprises pole pieces and a separator (2) stacked in sequence, the pole pieces comprising a positive pole piece and a negative pole piece, the positive pole piece and the negative pole piece being stacked in sequence; The types of the two adjacent positive electrode sheets are different, and the types of the positive electrode sheets include a first positive electrode sheet and a second positive electrode sheet; The types of two adjacent negative electrode sheets are different, and the types of negative electrode sheets include a first negative electrode sheet and a second negative electrode sheet.

11. A battery, characterized in that: It comprises a shell and a laminated battery core arranged in the shell, and the laminated battery core is the laminated battery core according to claim 10.

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