Laminated cell and battery

Abstract

The utility model relates to the technical field of batteries, and discloses a laminated battery cell and a battery, which comprises a plurality of layers of pole pieces and a plurality of layers of diaphragms which are sequentially laminated, the diaphragm extends out of the pole piece at the tab side edge of the pole piece, the bottom side edge opposite to the tab side edge, and a first side edge and a second side edge which are connected between the tab side edge and the bottom side edge, so as to form an extension part; and the multiple layers of extension parts corresponding to the multiple layers of diaphragms at least on the bottom side edge, the first side edge and the second side edge are arranged in a hot melting bonding manner. According to the utility model, the multiple layers of extension parts corresponding to the multiple layers of diaphragms are bonded on the edges of the at least three sides of the laminated battery cell in a hot melting manner, so that the pole pieces are wrapped in the adjacent diaphragms on the at least three sides, the diaphragms are prevented from moving, the limiting effect on the pole pieces is enhanced, dislocation caused by movement of the pole pieces is avoided, and the service life of the laminated battery cell is prolonged. Therefore, the problems of short circuit of the battery cell and reduction of overcurrent capability are avoided, and the overall performance of the laminated battery cell is ensured.

Description

Technical Field

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

[0002] A laminated battery cell refers to a battery cell formed by stacking a predetermined number of layers of positive electrode sheets, separators, and negative electrode sheets in sequence. After the lamination is completed, the laminated battery cell needs to be transported and assembled in the subsequent steps. In order to prevent the laminated battery cell from loosening, in the prior art, several strips of tape are usually used to stick and fix the edges of the battery cell unit along the thickness direction. However, the tape can only be attached to the two outermost separators, and the effect of sticking to the separator in the middle layer is limited. The separator and the electrode in the middle layer are still in a relatively loose state, which is easy to move or even dislocate, resulting in problems such as short circuit or reduced overcurrent capacity. Utility Model Content

[0003] In view of this, the utility model provides a laminated battery cell and a battery to solve the problem that the existing laminated battery cell diaphragms and pole pieces are relatively loose, easy to move or even misalign, resulting in short circuits or reduced current capacity.

[0004] In the first aspect, the utility model provides a stacked battery cell, comprising: a plurality of layers of pole sheets and a plurality of layers of diaphragms stacked in sequence, the diaphragm being located between two adjacent layers of the pole sheets, the diaphragm extending out of the pole sheet at the pole ear side edge of the pole sheet, the bottom side edge opposite to the pole ear side edge, and the first side edge and the second side edge connected between the pole ear side edge and the bottom side edge to form an extension portion, and at least the plurality of layers of the extension portions corresponding to the plurality of layers of the diaphragms at the bottom side edge, the first side edge and the second side edge are arranged by hot melt bonding.

[0005] Beneficial effect: The multi-layer extension parts corresponding to the multi-layer diaphragms are bonded to at least three side edges of the stacked battery cell by hot melting, so that the pole piece is wrapped in the adjacent diaphragm on at least three sides to prevent the diaphragm from moving, and the limiting effect on the pole piece is strengthened to prevent the pole piece from moving and causing dislocation, thereby avoiding the problem of battery cell short circuit and reduced current capacity, and ensuring the overall performance of the stacked battery cell.

[0006] In an optional embodiment, the laminated battery core forms a thermal cutting surface on one side corresponding to the bottom edge, one side corresponding to the first side edge, and one side corresponding to the second side edge, and the multiple layers of the extension parts are bonded together during the thermal cutting process.

[0007] Beneficial effect: For the stacking method of multiple sheets, after the stacking is completed, a plurality of continuously arranged battery cell units are cut into a plurality of independent battery cell units by hot cutting. Moreover, the hot cutting method is not only used to realize the cutting, but also can make the diaphragm melt and achieve bonding during the hot cutting process, which not only improves the production efficiency of the stacked battery cells, but also strengthens the limiting effect on the diaphragm and the pole piece.

[0008] In an optional embodiment, the multiple layers of extension parts are bonded together on the entire surface formed by the thickness direction of the laminated battery core and the length direction of the extension parts; or, the multiple layers of extension parts are bonded together by hot melt bonding to form a hot melt track along the length direction of the extension parts, and the hot melt track is a multi-point structure or a linear structure, and the hot melt track connects the multiple layers of extension parts along the thickness direction of the laminated battery core.

[0009] In an optional embodiment, the hot melt track is in a linear structure, and the linear structure is wavy, spiral, or zigzag.

[0010] In an optional implementation, the length of the laminated battery core is W, and the height of the laminated battery core is H, satisfying W / H≥2.

[0011] Beneficial effect: For laminated cells with a longer bottom edge, the multi-layer extension portion corresponding to the bottom edge of the laminated cell is bonded by hot melting, which has a better fixing effect on the diaphragm and the pole piece, ensuring the production quality and safety of the laminated cell.

[0012] In an optional embodiment, the pole piece includes a positive pole piece and a negative pole piece, the positive pole piece and the negative pole piece are stacked in sequence, and a notched corner structure is provided at the corners of the pole piece; in at least two adjacent pole pieces, located at the same corner, one of the pole pieces is provided with a first notched corner structure, and the other pole piece is provided with a second notched corner structure, wherein the size of the first notched corner structure is larger than the size of the second notched corner structure, so that the second notched corner structure protrudes from the first notched corner structure.

[0013] Beneficial effect: By setting the same corner position of adjacent pole pieces to different sizes, that is, one pole piece is provided with a first notch structure and the other pole piece is provided with a second notch structure, when the pole piece and the diaphragm are stacked, along the thickness direction of the battery cell, the second notch structure protrudes from the first notch structure, and there is a hollow area at the same corner position; therefore, 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.

[0014] In an optional embodiment, in at least two adjacent pole pieces of the same polarity, located at the same corner, one of the pole pieces is provided with a first missing corner structure, and the other pole piece is provided with a second missing corner structure.

[0015] In an optional embodiment, the pole pieces of the same polarity include a first pole piece and a second pole piece, and at any corner position among the four corners of the first pole piece and the second pole piece, 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.

[0016] In an optional embodiment, the negative electrode sheet is larger than the positive electrode sheet, and the outer contour of the negative electrode sheet protrudes beyond the outer contour of the positive electrode sheet.

[0017] In an optional embodiment, the missing corner structure includes a bevel corner or a rounded corner.

[0018] In an optional embodiment, the notch structure includes a rounded corner, the radius of the first notch structure is in the range of 1 mm to 5 mm, and the radius of the second notch structure is in the range of 0.2 mm to 2 mm.

[0019] In an optional embodiment, the electrode sheet includes a positive electrode sheet and a negative electrode sheet, and the positive electrode sheet and the negative electrode sheet are stacked in sequence; in at least two adjacent electrode sheets, and / or in at least two adjacent electrode sheets of the same polarity, the stacked electrode sheets are aligned.

[0020] In a second aspect, the utility model further provides a battery, comprising a shell and a laminated battery core arranged in the shell, wherein the laminated battery core is the laminated battery core mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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.

[0022] Figure 1 This is a schematic structural diagram of a laminated battery cell according to an embodiment of the utility model;

[0023] Figure 2 This is a schematic structural diagram of a first implementation of a plurality of battery cell units according to an embodiment of the utility model;

[0024] Figure 3This is a schematic structural diagram of a second implementation of a plurality of battery cell units according to an embodiment of the utility model;

[0025] Figure 4 for Figure 1 The schematic structural diagram of the cross section of the laminated battery cell shown in the thickness direction;

[0026] Figure 5 This is a schematic diagram of the structure of a hot melt track according to an embodiment of the utility model;

[0027] Figure 6 It is a schematic structural diagram of another hot melt track of an embodiment of the utility model;

[0028] Figure 7 A schematic diagram of the structure of another hot melt track according to an embodiment of the utility model;

[0029] Figure 8 It is a schematic structural diagram of another laminated battery cell according to an embodiment of the utility model;

[0030] Fig. 9 for Figure 8 A schematic diagram of the structure of a battery corresponding to the laminated battery cell shown;

[0031] Fig.10 A schematic cross-sectional view of a laminated battery cell at a corner of a pole piece in the prior art is shown;

[0032] Fig.11 A schematic structural diagram of a first electrode sheet and a second electrode sheet of a positive electrode sheet of a laminated battery cell of the present invention is shown;

[0033] Fig.12 Shows Fig.11 A schematic diagram of the structure after the first pole piece and the second pole piece are stacked;

[0034] Fig.13 Shows Fig.12 The enlarged schematic diagram at A in the middle;

[0035] Fig.14 A schematic structural diagram of a first electrode sheet and a second electrode sheet of a negative electrode sheet of a laminated battery cell of the utility model is shown;

[0036] Fig.15 Shows Fig.14 A schematic diagram of the structure after the first pole piece and the second pole piece are stacked;

[0037] Fig.16 Shows Fig.15 The enlarged schematic diagram of point B in the middle;

[0038] Fig.17 The schematic diagram of the structure of the laminated battery cell of the utility model is shown;

[0039] Fig.18 Shows Fig.17 Schematic diagram of CC section view.

[0040] Description of reference numerals:

[0041] 1', positive electrode; 2', negative electrode; 3', diaphragm;

[0042] 1. Pole piece; 11. Positive electrode piece; 12. Negative electrode piece; 13. First pole piece; 14. Second pole piece; 101. Pole ear side edge; 102. Bottom side edge; 103. First side edge; 104. Second side edge; 2. Diaphragm; 201. Extension portion; 3. Notched structure; 4. Hot melt track; 5. Shell; R, first notched structure; r, second notched structure. DETAILED DESCRIPTION

[0043] 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.

[0044] Combine the following Figures 1 to 18 , describing an embodiment of the utility model.

[0045] According to an embodiment of the utility model, on the one hand, a stacked battery cell is provided, comprising: a multi-layer electrode sheet 1 and a multi-layer diaphragm 2 stacked in sequence, the diaphragm 2 being located between two adjacent layers of the electrode sheets 1, the diaphragm 2 extending out of the electrode sheet 1 at the pole ear side edge 101 of the electrode sheet 1, the bottom side edge 102 opposite to the pole ear side edge 101, and the first side edge 103 and the second side edge 104 connected between the pole ear side edge 101 and the bottom side edge 102 to form an extension portion 201, and at least the multi-layer extension portion 201 corresponding to the multi-layer diaphragm 2 at the bottom side edge 102, the first side edge 103 and the second side edge 104 is arranged by hot melt bonding.

[0046] The multi-layer extension parts 201 corresponding to the multi-layer diaphragm 2 are bonded to at least three side edges of the stacked battery cell by hot melting, so that the pole piece 1 is wrapped in the adjacent diaphragm 2 on at least three sides to prevent the diaphragm 2 from moving and strengthen the restriction effect on the pole piece 1 to prevent the pole piece 1 from moving and causing dislocation, thereby avoiding the problem of battery cell short circuit and reduced current capacity, thereby ensuring the overall performance of the stacked battery cell.

[0047] It is worth noting that in the production process of the laminated battery cell, the laminated battery cell can be laminated in a single-piece stacking manner, that is, one electrode sheet 1 is stacked each time, and a separator 2 is stacked between the adjacent positive electrode sheet 11 and the negative electrode sheet 12, so that each lamination process forms an independent battery cell unit. In the related art, the laminated battery cell is fixed in the thickness direction by pasting tape at least on the bottom side edge 102, the first side edge 103 and the second side edge 104 of the battery cell.

[0048] Alternatively, in the production process of laminated cells, in order to improve production efficiency, a multi-sheet stacking method is adopted, that is, multiple electrode sheets 1 are stacked at the same time, and a diaphragm 2 material strip is laid between adjacent multiple positive electrode sheets 11 and multiple negative electrode sheets 12, so as to form multiple continuously arranged battery cell units. After the lamination is completed, the diaphragm 2 between adjacent battery cell units is cut off to form multiple independent battery cell units, and then the laminated battery cell is fixed in the thickness direction by sticking tape at least on the bottom side edge 102, the first side edge 103 and the second side edge 104 of the battery cell unit; or, as Figure 2 As shown, after the lamination is completed, the diaphragm 2 between adjacent battery cells is cut by heat melting to separate the diaphragm 2 between two adjacent battery cells, thereby forming a plurality of independent battery cells. During the heat cutting process, the diaphragm 2 on both sides (the first side edge 103 and the second side edge 104) of the battery cell unit is heat melted to achieve adhesion, and then the tape is pasted on the bottom side edge 102 of the battery cell unit for adhesion and fixation.

[0049] The above method of fixing the laminated battery cell along the thickness direction by sticking tape not only has limited fixing effect, but also during the gluing process, the gluing head is easy to fold the diaphragm 2, resulting in the exposure of the pole piece 1 and causing a short circuit problem.

[0050] It is worth noting that if Figure 3 As shown, during lamination, two rows of multiple columns of pole pieces 1 are simultaneously stacked on the diaphragm 2 material strip. After lamination is completed, the left edge of the diaphragm 2 of the pole piece 1 in the leftmost column, the diaphragm 2 between two adjacent columns, the right edge of the diaphragm 2 of the pole piece 1 in the rightmost column, and the diaphragm 2 between two rows of pole pieces 1 are heat-cut, and each cell unit after heat-cutting is a three-side hot-melt laminated cell. That is, the laminated cell forms a hot-cut surface on one side corresponding to the bottom side edge 102, one side corresponding to the first side edge 103, and one side corresponding to the second side edge 104, and the multi-layer extension portion 201 is bonded and arranged during the hot-cutting process. For the lamination method of multiple sheets, after lamination is completed, a plurality of continuously arranged cell units are cut into a plurality of independent cell units by a hot-cutting method, and the hot-cutting method is adopted to not only realize cutting, but also to make the diaphragm 2 hot-melt and bond during the hot-cutting process, which not only improves the production efficiency of the laminated cell, but also strengthens the limiting effect on the diaphragm 2 and the pole piece 1.

[0051] It should be noted that before the multi-layer extension portion 201 is hot-melted, the multi-layer separators 2 of the laminated battery cell of this embodiment are all independent sheets, that is, there is no connection between two adjacent layers of separators 2 .

[0052] It should be noted that if Figure 1 and Figure 4 As shown, the edge of the diaphragm 2 extends a certain width beyond the edge of the pole piece 1, thereby forming an extension portion 201. Hot melting is to heat the extension portion 201, and the extension portion 201 shrinks due to the heat and is bonded together by drawing, so that the multi-layer extension portion 201 is bonded to each other, thereby sealing the three sides of the laminated battery cell. Further, after hot melting, the extension portion 201 shrinks inward, so that the edge of the diaphragm 2 is closer to the edge of the pole piece 1, so that the diaphragm 2 exerts a certain enveloping force on the pole piece 1, and reduces the activity space of the pole piece 1, further preventing the pole piece 1 from moving.

[0053] In one embodiment, Figure 4 As shown, the multi-layer extension part 201 is bonded to the entire surface formed in the thickness direction of the laminated battery core and the length direction of the extension part 201.

[0054] It is worth noting that the three-side extension parts 201 of the laminated battery core are heat-cut by using a heat-cutting wire, and the multi-layer extension parts 201 are bonded during the heat-cutting process.

[0055] Of course, in other alternative embodiments, the multi-layer extension part 201 is arranged by hot-melt bonding to form a hot-melt track 4 along the length direction of the extension part 201, and the hot-melt track 4 is a multi-point structure or a linear structure, and the hot-melt track 4 connects the multi-layer extension part 201 along the thickness direction of the laminated battery core. Figures 5 to 7 As shown, the hot melt track 4 is in a linear structure, and the linear structure is wavy, spiral, or zigzag.

[0056] It is worth noting that a hot melt head is used to hot melt the edges of the three-side extension parts 201 of the laminated battery core according to a predetermined hot melt track 4 so that the multi-layer extension parts 201 are bonded to each other.

[0057] It should be noted that when the hot melt track 4 adopts a multi-point structure, adjacent point structures are also bonded.

[0058] It is worth mentioning that please refer to Figure 1 The length direction of the extension portion 201 corresponding to the first side edge 103 and the second side edge 104 is the height direction of the laminated battery core, and the length direction of the extension portion 201 corresponding to the bottom side edge 102 is the length direction of the laminated battery core.

[0059] In one embodiment, Figure 8As shown, the length of the laminated core is W, and the height of the laminated core is H, satisfying W / H ≥ 2. For laminated cores with a longer bottom edge 102, the multilayer extension portion 201 corresponding to the bottom edge 102 of the laminated core is bonded by hot melting, which has a better fixing effect on the diaphragm 2 and the pole piece 1, ensuring the production quality and safety of the laminated core.

[0060] It is worth noting that for laminated cells with a longer bottom edge 102, if the adhesive tape method in the related art is used for fixing, the fixing effect of the bottom edge 102 is poor, and the diaphragm 2 and the pole piece 1 located in the middle layer of the laminated cell are more likely to be misaligned.

[0061] It should be noted that the battery cell that meets W / H≥2 has a lower height, is more suitable for automobile use, and can further reduce the height of the automobile chassis. Furthermore, for the electrode sheet 1 of the battery cell, the width of the positive and negative pole ears (along the length direction of the laminated battery cell) can also be made as wide as possible to improve the current capacity and charge and discharge performance of the battery cell.

[0062] In one embodiment, Figures 11 to 18 As shown, the pole piece 1 includes a positive pole piece 11 and a negative pole piece 12, which are stacked in sequence, and a notched corner structure 3 is provided at the corner of the pole piece 1; in at least two adjacent pole pieces 1, located at the same corner, one pole piece 1 is provided with a first notched corner structure R, and the other pole piece 1 is provided with a 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, so that the second notched corner structure r protrudes from the first notched corner structure R.

[0063] By setting the same corner position of adjacent pole pieces 1 to different sizes, that is, one pole piece 1 is provided with a first notched corner structure R, and the other pole piece 1 is provided with a second notched corner structure r, when the pole piece 1 and the diaphragm 2 are stacked, along the thickness direction of the battery cell, the second notched corner structure r protrudes from the first notched corner structure R, and there is a hollow area at the same corner position; therefore, 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 1, and reduce the risk of burrs at the corners of the pole piece 1 piercing the diaphragm 2 during the hot pressing process.

[0064] It is worth noting that in the related art, the positive electrode sheet 1' and the negative electrode sheet 2' are made by cutting the material strip (hardware die cutting, laser cutting, etc.). After cutting, burrs will form on the four corners of the electrode sheet 1. In the subsequent stacking and hot pressing process, the pressure will cause the burrs to pierce the diaphragm 2 and cause the battery to short-circuit and become scrapped. Since the battery cell structure usually adopts a negative-in-positive structure (the negative electrode sheet 2' is larger than and covers the positive electrode sheet 1'), especially at the four corners of the positive electrode sheet 1', such as Fig.10As shown, along the thickness direction of the battery cell ( Fig.10 There are pole pieces 1 (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 1, making it very easy for the corner burrs of the positive pole piece 1' to pierce the diaphragm 2.

[0065] First of all, it should be noted that the electrode sheet 1 in this embodiment includes a positive electrode sheet 11 and a negative electrode sheet 12, and the laminated battery cell is formed by stacking the positive electrode sheet 11, the separator 2 and the negative electrode sheet 12 in sequence. The structural form of the laminated battery cell is "... separator 2-negative electrode sheet 12-separator 2-positive electrode sheet 11-separator 2-negative electrode sheet 12-separator 2..."

[0066] like Fig.11 As 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.

[0067] It should be noted that Fig.11 The corners of the pole piece 1 refer to the intersection of the top edge (the edge of the pole ear side) and the side edge (the first side edge and the second side edge), and the intersection of the bottom edge (the bottom side edge) and the side edge (the first side edge and the second side edge). Therefore, the pole piece 1 has four corner positions.

[0068] 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.

[0069] 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.

[0070] like Fig.12 and Fig.13As 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 notched corner structure R and the other pole piece 1 is provided with the second notched corner 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.

[0071] Therefore, in the technical solution of this embodiment, in adjacent pole pieces 1 of the laminated battery cell, at the same corner, one pole piece 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. Fig.17 and Fig.18 As shown, at the corner position of the pole piece 1 of the laminated battery cell, the second notch structure r protrudes from the part of 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.

[0072] In one embodiment, among at least two adjacent pole pieces 1 of the same polarity, at the same corner, one pole piece 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.

[0073] It should be noted that “adjacent electrode sheets 1 ” may include adjacent positive electrode sheets 11 , may include adjacent negative electrode sheets 12 , or may include adjacent positive electrode sheets 11 and negative electrode sheets 12 .

[0074] Furthermore, “adjacent electrode sheets 1 ” may be every two adjacent electrode sheets 1 in the laminated battery cell, including every two adjacent positive electrode sheets 11 , every two adjacent negative electrode sheets 12 , and every two adjacent positive electrode sheets 11 and negative electrode sheets 12 .

[0075] Furthermore, “adjacent electrode sheets 1 ” may also be only partially adjacent electrode sheets 1 in the laminated battery cell, including at least two adjacent positive electrode sheets 11 , at least two adjacent negative electrode sheets 12 , and at least two adjacent positive electrode sheets 11 and negative electrode sheets 12 .

[0076] In one embodiment, Fig.11 and Fig.14 As shown, the pole piece 1 of the same polarity includes a first pole piece 13 and a second pole piece 14. At any corner position among 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.

[0077] Specifically, the electrode sheet 1 of the same polarity includes 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 14. Those skilled in the art can understand that the positive electrode sheet 11 includes two specifications of the electrode sheet 1 form (AB sheet form), and the negative electrode sheet 12 also includes two specifications of the electrode sheet 1 form (AB sheet form).

[0078] like Fig.18 As shown, and Fig.18 The form of the stacked battery cell from top to bottom is “… diaphragm 2-first pole piece 13 of negative pole piece 12-diaphragm 2-first pole piece 13 of positive pole piece 11-diaphragm 2-second pole piece 14 of negative pole piece 12-diaphragm 2-second pole piece 14 of positive pole piece 11…”.

[0079] In one embodiment, the negative electrode sheet 12 is larger than the positive electrode sheet 11 , and an outer contour of the negative electrode sheet 12 protrudes from an outer contour of the positive electrode sheet 11 .

[0080] It is worth noting that in this embodiment, the laminated battery cell adopts the traditional "negative-enclosed-positive" structure in the industry, that is, the negative electrode sheet 12 is larger than the positive electrode sheet 11, and the outer contour of the negative electrode sheet 12 protrudes from the outer contour of the positive electrode sheet 11. Fig.17 and Fig.18 As shown, the corners of adjacent negative electrode sheets 12 have been separated by the positive electrode sheets 11 to form a hollow area, but the corners of the positive electrode sheets 11 are susceptible to the pressure continuously transmitted by the positive electrode sheets 11. Therefore, in this embodiment, it is preferred that at least two adjacent positive electrode sheets 11 are located at the same corner, one of the positive electrode sheets 11 is provided with a first corner-cut structure R, and the other positive electrode sheet 11 is provided with a second corner-cut structure r.

[0081] Combination Fig.18 As shown, such a configuration enables the laminated battery cell to generate a second corner-cut structure r protruding from the hollow area of ​​the first corner-cut structure R at the same corner of the positive electrode sheet 11. Therefore, in the subsequent hot pressing process, the hollow area can buffer and reduce the pressure, thereby greatly reducing the risk of burrs piercing the diaphragm 2 during the hot pressing process at the positive electrode sheet 11.

[0082] like Figures 13 to 16 As shown, further, in this embodiment, in at least two adjacent negative electrode sheets 12, at the same corner, one of the negative electrode sheets 12 is provided with a first corner-cut structure R, and the other negative electrode sheet 12 is provided with a second corner-cut structure r.

[0083] like Fig.18 As shown, since the size of the negative electrode sheet 12 is larger than that of the positive electrode sheet 11, the first corner-cut structure R of the negative electrode sheet 12 still protrudes beyond the second corner-cut structure r of the positive electrode sheet 11 after stacking. Fig.18 As shown, a sawtooth-shaped stepped structure is formed at the corners of the electrode 1 of the laminated battery cell, which increases the number of hollow areas, thereby greatly reducing the risk of burrs piercing the diaphragm 2 of the laminated battery cell during hot pressing.

[0084] As described above, since the pole piece 1 has four corner positions, for the adjacent positive pole piece 11 and negative pole piece 12, the condition "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" can be satisfied at one corner, the condition "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" can be satisfied at two corners, the condition "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" can be satisfied at three corners, or the condition "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" can be satisfied at all four corners.

[0085] Preferably, the four corners of adjacent positive electrode sheets 11 of the present embodiment all satisfy "one of the electrode sheets 1 is provided with a first corner-cut structure R, and the other electrode sheet 1 is provided with a second corner-cut structure r", and the four corners of adjacent negative electrode sheets 12 of the present embodiment also all satisfy "one of the electrode sheets 1 is provided with a first corner-cut structure R, and the other electrode sheet 1 is provided with a second corner-cut structure r".

[0086] In an embodiment not shown, if the positive electrode sheet 11 and the negative electrode sheet 12 are the same size, the adjacent positive electrode sheets 11 and negative electrode sheets 12 can be arranged to satisfy the above-mentioned condition of "being located at the same corner, one electrode sheet 1 is provided with a first corner-cut structure R, and the other electrode sheet 1 is provided with a second corner-cut structure r".

[0087] In one embodiment, the notched corner structure 3 includes a beveled corner or a rounded corner.

[0088] 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.

[0089] 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:

[0090] 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.

[0091] 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.

[0092] 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.

[0093] Based on this, Fig.18 As shown, in fact, in the laminated battery cell of this embodiment, the first notch structure R of the positive electrode sheet 11 is still subjected to the pressure transmitted by the electrode sheet 1 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 11, 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 1, so that the probability of the burr piercing the diaphragm 2 during the hot pressing process is low.

[0094] Furthermore, the negative electrode sheet 12 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 11 between the negative electrode sheets 12, so the risk of burrs piercing the diaphragm 2 is not great.

[0095] Of course, in other alternative embodiments, the electrode sheet 1 includes a positive electrode sheet 11 and a negative electrode sheet 12, and the positive electrode sheet 11 and the negative electrode sheet 12 are stacked in sequence; in at least two adjacent electrode sheets 1, and / or in at least two adjacent electrode sheets 1 of the same polarity, the stacked electrode sheets 1 are aligned. Similarly, "adjacent electrode sheets 1" may include adjacent positive electrode sheets 11, may include adjacent negative electrode sheets 12, or may include adjacent positive electrode sheets 11 and negative electrode sheets 12. It should be noted that the overall risk of burrs piercing the diaphragm 2 during hot pressing is greatly reduced in the laminated battery cell of this embodiment compared to the laminated battery cell in which electrode sheets 1 of a single size specification are stacked in the alternative embodiment.

[0096] According to the embodiments of the present utility model, Fig. 9 As shown, on the other hand, a battery is also provided, including a shell 5 and a laminated battery core arranged in the shell 5, and the laminated battery core is the laminated battery core mentioned above.

[0097] 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 laminated battery cell, characterized in that: include: A plurality of layers of pole pieces (1) and a plurality of layers of diaphragms (2) are stacked in sequence, wherein the diaphragm (2) is located between two adjacent layers of the pole pieces (1), and the diaphragm (2) extends out of the pole piece (1) at a side edge (101) of the pole ear of the pole piece (1), a bottom side edge (102) opposite to the side edge (101) of the pole ear, and a first side edge (103) and a second side edge (104) connected between the side edge (101) of the pole ear and the bottom side edge (102) to form an extension portion (201), wherein at least the plurality of layers of the diaphragm (2) corresponding to the bottom side edge (102), the first side edge (103) and the second side edge (104) are arranged by hot-melt bonding.

2. The laminated battery cell according to claim 1, characterized in that: The laminated battery core forms a thermal cutting surface on one side corresponding to the bottom side edge (102), one side corresponding to the first side edge (103), and one side corresponding to the second side edge (104), and the multiple layers of the extension part (201) are bonded together during the thermal cutting process.

3. The laminated battery cell according to claim 1, characterized in that: The multi-layer extension parts (201) are bonded to the entire surface formed in the thickness direction of the laminated battery core and the length direction of the extension parts (201); or, The multiple layers of the extension part (201) are arranged by hot-melt bonding to form a hot-melt track (4) along the length direction of the extension part (201); the hot-melt track (4) is in a multi-point structure or a linear structure; the hot-melt track (4) connects the multiple layers of the extension part (201) along the thickness direction of the laminated battery core.

4. The laminated battery cell according to claim 3, characterized in that: The hot melt track (4) is in a linear structure, and the linear structure is wavy, spiral, or zigzag.

5. The laminated battery cell according to any one of claims 1 to 4, characterized in that: The length of the laminated battery core is W, and the height of the laminated battery core is H, satisfying W / H≥2.

6. The laminated battery cell according to any one of claims 1 to 4, characterized in that: 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, and a corner-cut structure (3) is provided at the corner of the pole piece (1); In at least two adjacent pole pieces (1), located at the same corner, 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 greater 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).

7. The laminated battery cell according to claim 6, characterized in that: In at least two adjacent pole pieces (1) of the same polarity, located at the same corner, 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).

8. The laminated battery cell according to claim 6, characterized in that: The pole piece (1) of the same polarity comprises a first pole piece (13) and a second pole piece (14); at any corner position among 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).

9. The laminated battery cell according to claim 6, characterized in that: The negative electrode sheet (12) is larger than the positive electrode sheet (11), and the outer contour of the negative electrode sheet (12) protrudes from the outer contour of the positive electrode sheet (11).

10. The laminated battery cell according to claim 6, characterized in that: The missing corner structure (3) comprises an oblique corner or a rounded corner.

11. The laminated battery cell according to claim 10, 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.

12. The laminated battery core according to any one of claims 1 to 4, characterized in that: The electrode sheet (1) comprises a positive electrode sheet (11) and a negative electrode sheet (12), wherein the positive electrode sheet (11) and the negative electrode sheet (12) are stacked in sequence; In at least two adjacent pole pieces (1), and / or in at least two adjacent pole pieces (1) of the same polarity, the pole pieces (1) arranged in a stacked manner are arranged in an aligned manner.

13. A battery, characterized in that: The invention comprises a shell (5) and a laminated battery core arranged in the shell (5), wherein the laminated battery core is the laminated battery core according to any one of claims 1 to 12.

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