Laminated battery cell, preparation method thereof and pole piece structure

Abstract

The invention discloses a laminated battery cell, a preparation method thereof and a pole piece structure, the laminated battery cell comprises a first pole piece assembly, a diaphragm and a second pole piece assembly, the first pole piece assembly comprises a first current collector and a first active substance, the first current collector is provided with a plurality of coating areas, and a spacer area is arranged between two adjacent coating areas; first active substances are arranged on the coating areas, the coating areas and the first active substances on the coating areas form first pole pieces, and every two adjacent first pole pieces are connected through a spacer area; the diaphragms comprise a first diaphragm and a second diaphragm, and the first diaphragm and the second diaphragm are respectively arranged on two sides of the first pole piece and the spacer region; the second pole piece assembly comprises a plurality of second pole pieces, and the second pole pieces are arranged on the side, away from the first pole piece, of the first diaphragm and the side, away from the first pole piece, of the second diaphragm. According to the first pole piece assembly, the first pole pieces are directly and continuously supplied in a continuous mode, dust pollution caused by pole piece cutting operation is avoided, and the risk that dust enters a core package is effectively reduced.

Description

Technical Field

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

[0002] With the rapid development of new energy vehicles and the energy storage industry, market demand for high-energy-density lithium-ion batteries continues to rise. The stacking process, which enables high-precision alignment of electrodes and separators, improving cell safety and cycle life, has become the mainstream manufacturing method for high-end products such as high-nickel ternary and solid-state batteries.

[0003] However, the manufacturing field of laminated battery cells faces multiple technical bottlenecks: (1) The traditional Z-type lamination process starts with the unwinding of the diaphragm, which is then introduced into the main lamination table through the roller and tension mechanism. The main lamination table drives the diaphragm to move back and forth, forming a Z-shaped fold. At the same time, the robot places the cut positive and negative electrodes on the diaphragm. After stacking them to the set number of battery cell layers, the diaphragm tail winding, diaphragm cutting, and adhesive lamination are completed. It relies on the robot to transport the individual cells one by one, which is inefficient and is easily affected by gravity and airflow during the transportation process, causing the diaphragm to wrinkle. (2) Hot composite lamination is similar to the traditional winding process. The positive and negative electrodes and diaphragms are first composited into a specific structure, and then wound into a battery cell. Its dynamic tension control is difficult, and there are problems with the misalignment of the tabs and the alignment control during the lamination process. (3) Hot composite lamination processes the positive and negative electrodes and diaphragms separately to form individual cells, and then the individual cells are transported to the lamination position by the robot for stacking to form a battery cell. It relies on a robot to carry the unit wafers, which is slow and leads to low production efficiency. The positioning accuracy and stability of the robot have a great impact on the stacking accuracy of the battery cell, which easily leads to poor alignment of the electrodes. (4) Hot composite stacking is to form a unit wafer by cutting the negative electrode and the positive electrode, and then forming a unit wafer with the diaphragm. The wafers are stacked in a similar way to Z stacking but without cutting the diaphragm. The wafers are dropped at high speed to form a Z-shaped stack, and finally the battery cell is formed. In the process of cutting the negative electrode, copper powder pollution will be generated. Once the copper powder enters the core package, it will cause problems such as short circuit of the core package and poor k value. A dust removal system must be configured, which restricts the compactness of the production line. Summary of the Invention

[0004] In order to overcome at least one of the defects described in the above-mentioned prior art, one of the purposes of the present application is to provide a laminated battery cell, which adopts a continuous first electrode sheet and a cut second electrode sheet. When the first electrode sheet and the second electrode sheet are thermally composited and stacked, the cutting and transportation steps of the first electrode sheet can be avoided, thereby effectively reducing the generation of dust.

[0005] The second purpose of the present application is to provide a method for preparing a laminated battery cell, which prepares a continuous first electrode sheet and a cut second electrode sheet, and then composites the two with a diaphragm and stacks them to form a laminated battery cell, so that the first electrode sheet can be supported by the uncut spacing area when folded, avoiding the problem of reduced battery cell alignment due to deformation of the electrode sheet.

[0006] The third purpose of this application is to provide a pole piece structure for a laminated battery cell, which adopts a continuous first pole piece assembly so that the uncut spacing area during the lamination process can provide support for two adjacent first pole pieces, reduce the deformation of the pole pieces, and maintain the flatness of the pole pieces.

[0007] One of the technical solutions adopted by this application to solve the problem is:

[0008] A laminated battery cell, comprising:

[0009] A first pole piece assembly includes a first current collector and a first active material, wherein the first current collector is provided with a plurality of coating areas, and a spacer area is provided between two adjacent coating areas; the coating areas are provided with the first active material, and the coating areas and the first active material thereon form a first pole piece, and two adjacent first pole pieces are connected by the spacer area;

[0010] a diaphragm, comprising a first diaphragm and a second diaphragm, wherein the first diaphragm and the second diaphragm are respectively disposed on both sides of the first pole piece and the spacer area;

[0011] The second pole piece assembly includes a plurality of second pole pieces, wherein the second pole pieces are arranged on a side of the first diaphragm facing away from the first pole piece and on a side of the second diaphragm facing away from the first pole piece.

[0012] As a preferred technical solution of the present application, the orthographic projection of the second pole piece on the diaphragm coincides with the orthographic projection of the first pole piece on the diaphragm.

[0013] As a preferred technical solution of the present application, the second pole piece includes a second current collector and a second active material, and the second active material is continuously arranged on the second current collector.

[0014] As a preferred technical solution of the present application, the first electrode is a negative electrode, and the second electrode is a positive electrode.

[0015] The second technical solution adopted by this application to solve the problem is:

[0016] A method for preparing a laminated battery core, for preparing the laminated battery core as described above, comprises the following steps:

[0017] First pole piece preparation step 1: forming a plurality of coating areas on a whole first current collector, separating the plurality of coating areas, and providing a spacing area between two adjacent coating areas;

[0018] First electrode sheet preparation step 2: coating the first active material on each of the coating areas to form a first electrode sheet after coating the first active material on each of the coating areas, and connecting two adjacent first electrode sheets via the spacer area;

[0019] Second pole piece preparation step 1: continuously coating the second active material on a whole second current collector;

[0020] Second pole piece preparation step 2: cutting the second current collector coated with the second active material into a plurality of second pole pieces;

[0021] Cell preparation step 1: Compounding a diaphragm on both sides of the plurality of first pole pieces and the spacer area; detecting the position of the first pole pieces, and placing the second pole piece on the corresponding first pole piece, so that one first pole piece, the second pole piece placed thereon, and the diaphragm form a unit cell;

[0022] The second step of preparing the battery cell is to continuously stack the unit sheets in a zigzag path to prepare a stacked battery cell.

[0023] As a preferred technical solution of the present application, the first active material is coated on both sides of the coating area, and the first pole piece is formed after the first active material is coated on both sides of each coating area; the second active material is continuously coated on both sides of the second current collector.

[0024] As a preferred technical solution of the present application, the area of a single side of the coating region is the same as the area of a single side of the second pole piece.

[0025] As a preferred technical solution of the present application, a plurality of the coating areas and the spacing areas are partitioned along the length direction of the first current collector so that the plurality of first pole pieces are spaced apart along the length direction of the first current collector; the second pole piece falls on one side or both sides of the first pole piece, and one first pole piece and one or two second pole pieces and the diaphragm falling thereon form a unit piece.

[0026] As a preferred technical solution of the present application, two unit sheets adjacent to each other in the length direction of the first current collector are folded along the spacing area so that each unit sheet is stacked in the thickness direction of the first current collector.

[0027] The third technical solution adopted by this application to solve the problem is:

[0028] A pole piece structure includes the first pole piece assembly as described above.

[0029] In summary, the laminated battery cell and its preparation method and electrode structure provided in this application have the following technical effects:

[0030] 1) The laminated battery cell of the present application uses a continuous first electrode sheet and a cut second electrode sheet. When the first electrode sheet and the second electrode sheet are thermally composited and stacked, the cutting and transportation steps of the first electrode sheet can be avoided, effectively reducing the generation of dust.

[0031] 2) The preparation method of the laminated battery cell of the present application prepares a continuous first electrode sheet and a cut second electrode sheet, and then composites the two with a diaphragm and stacks them to form a laminated battery cell, so that the first electrode sheet can be supported by the uncut spacing area when folded, reducing the deformation of the electrode sheet, thereby improving the alignment of the core package.

[0032] 3) The electrode structure of the laminated battery cell of the present application adopts a continuous first electrode assembly, so that the uncut spacing area during the lamination process can provide support for the two adjacent first electrode sheets, reduce the deformation of the electrode sheets, maintain the flatness of the electrode sheets, and make the alignment more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic structural diagram of the first pole piece assembly according to an embodiment of the present application;

[0034] Figure 2 This is a schematic structural diagram of the second pole piece in an embodiment of the present application;

[0035] Figure 3 This is a schematic structural diagram of a first pole piece assembly, a diaphragm, and a plurality of second pole pieces combined in an embodiment of the present application;

[0036] Figure 4 This is a schematic structural diagram of the laminated battery cell preparation equipment according to an embodiment of the present application.

[0037] The meanings of the reference numerals are as follows:

[0038] 10. First current collector; 11. Coating area; 12. Spacer area; 13. First active material; 14. First pole piece; 20. Second current collector; 21. Second active material; 22. Second pole piece; 30. Diaphragm; 31. First diaphragm; 32. Second diaphragm; 40. Unit piece; 50. First unwinding assembly; 51. First mounting shaft; 52. First traction wheel; 53. First pole piece strip; 60. Diaphragm unwinding assembly; 61. Third mounting shaft; 62. Third traction wheel; 70. Second unwinding assembly; 71. Second mounting shaft; 72. Second traction wheel; 73. Second pole piece strip; 80. Cutting device; 90. First pressing assembly; 100. Second pressing assembly; 110. Detection device; 120. Lamination table. DETAILED DESCRIPTION

[0039] For better understanding and implementation, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0040] In the description of this application, it should be noted that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, 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, they cannot be understood as limiting this application.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0042] Example 1

[0043] This embodiment discloses a laminated battery cell, see Figure 3 , which includes a first pole piece assembly, a diaphragm 30 and a second pole piece assembly. Figure 1 The first electrode assembly includes a first current collector 10 and a first active material 13. Specifically, the first current collector 10 is provided with a plurality of coating areas 11, and a spacer area 12 is provided between two adjacent coating areas 11. The first active material 13 is provided on the coating area 11, and the coating area 11 and the first active material 13 thereon form a first electrode 14, and two adjacent first electrode sheets 14 are connected by the spacer area 12.

[0044] See Figure 3The diaphragm 30 includes a first diaphragm 31 and a second diaphragm 32, and the first diaphragm 31 and the second diaphragm 32 are respectively disposed on both sides of the first pole piece 14 and the spacer 12. In addition, the second pole piece assembly includes a plurality of second pole pieces 22, and the second pole pieces 22 are disposed on the side of the first diaphragm 31 facing away from the first pole piece 14 and the side of the second diaphragm 32 facing away from the first pole piece 14.

[0045] Based on this structure, when using the laminated battery cell of the present application, when preparing the first electrode 14, the first active material 13 can be first coated on the coating area 11 of the first current collector 10 to form a plurality of first electrode sheets 14, and two adjacent first electrode sheets 14 are connected by a spacer area 12 that is not coated with the first active material 13.

[0046] When assembling the battery cell, the first diaphragm 31 and the second diaphragm 32 are first covered on both sides of the first electrode sheet 14 and the spacer 12, respectively. The diaphragm 30 is then bonded to the edge of the first electrode sheet 14 through thermal lamination to form a continuous first electrode sheet strip 53. Multiple second electrode sheets 22 are then placed on both sides of the first electrode sheet strip 53. Specifically, the multiple second electrode sheets 22 are stacked one-to-one on each first electrode sheet 14, so that a first electrode sheet 14 and the second electrode sheet 22 thereon form a unit cell 40.

[0047] The leading cell 40 is then moved downward. Since the first pole pieces 14 in two adjacent cell pieces 40 are connected by the spacer 12, multiple cell pieces 40 fall naturally and continuously under the action of gravity, with the subsequent cell piece 40 stacked on the previous cell piece 40. When the predetermined number of cell pieces 40 is reached, the movement of the first pole piece belt 53 and the falling of the second pole piece 22 are stopped. The entire stacked structure is then finalized and fixed, for example, by gluing to ensure its stability.

[0048] The first electrode piece 14 and the second electrode piece 22 have opposite polarities. The diaphragm 30 isolates and protects the positive and negative electrode pieces. It also moves synchronously with the movement of the first electrode piece belt 53 to ensure the continuity of the entire lamination process. The diaphragm 30 can be a PE film, a ceramic-coated diaphragm 30, or the like as known in the art.

[0049] In addition, the first current collector 10 can be copper foil or aluminum foil, and the first active material 13 coated on its coating area 11 is graphite or lithium cobalt oxide. In this embodiment, the first current collector 10 is copper foil, the first active material 13 is graphite, and the first electrode 14 is a negative electrode.

[0050] It should be noted that in the traditional drop-stack process, the electrode sheets are cut before being stacked. Whether cutting with a mechanical cutter or laser cutting, this will damage the electrode sheet material, causing debris and dust to form on the negative electrode copper foil and the active material attached to the surface. Once this dust enters the core package, it may become a hidden danger of internal short circuit in the battery cell. At the same time, if the cutting is inaccurate or there is omission during transportation, the negative electrode sheet may be missing from the core package. Moreover, the electrode sheet is prone to wrinkling or shifting during transportation due to gravity or uneven tension.

[0051] The first electrode assembly of the present application does not need to be cut, and is directly supplied continuously in the form of continuous electrodes, avoiding the cutting and handling steps. The first electrode 14 is a negative electrode, which can avoid the possibility of dust generated by the cutting operation and effectively reduce the risk of dust entering the core package. At the same time, it also reduces the phenomenon of missing pieces due to cutting errors or loss during transportation. Among them, since the two adjacent first electrode pieces 14 are connected and supported by the spacer area 12, and the copper foil of the spacer area 12 has a certain ductility and rigidity, it can provide support during the lamination process, reduce the deformation of the electrode piece, maintain the flatness of the electrode piece, and make the alignment more accurate.

[0052] Therefore, the present application provides continuous negative electrode sheets, with the short sides of two adjacent negative electrode sheets connected by the copper foil in the spacer area 12, so that they can be supported during the lamination process, reducing deformation of the electrode sheets, thereby maintaining the flatness of the electrode sheets, improving production efficiency and yield rate. At the same time, it avoids problems such as inaccurate cutting, missing pieces during handling, and wrinkling and offset of the electrode sheets.

[0053] As a preferred technical solution of the present application, the orthographic projection of the second pole piece 22 on the diaphragm 30 coincides with the orthographic projection of the first pole piece 14 on the diaphragm 30 .

[0054] As a result, when the orthographic projection of the second electrode sheet 22 on the diaphragm 30 coincides with the orthographic projection of the first electrode sheet 14 on the diaphragm 30, the relative positions of the positive and negative electrode sheets within the battery cell precisely correspond. During the charge and discharge process, current can be conducted more evenly between the positive and negative electrode sheets, making the electric field distribution more uniform. This helps avoid localized current overshoot or undershoot, reduces polarization within the battery cell, and improves the overall charge and discharge performance and efficiency of the battery cell.

[0055] As a preferred technical solution of this application, see Figure 2 The second electrode 22 includes a second current collector 20 and a second active material 21 , and the second active material 21 is continuously disposed on the second current collector 20 .

[0056] When preparing the second pole piece 22, the second active material 21 can be continuously disposed on a whole current collector, and then the whole current collector coated with the second active material 21 can be cut into multiple second pole pieces 22 of the same size. In this case, each second pole piece 22 includes the second current collector 20 and the second active material 21.

[0057] The second current collector 20 is aluminum foil, and the second active material 21 is lithium cobalt oxide.

[0058] As a preferred technical solution of the present application, the first electrode 14 is a negative electrode, and the second electrode 22 is a positive electrode.

[0059] That is, in this embodiment, the negative electrode sheet is a continuous sheet that does not need to be cut, and two adjacent negative electrode sheets are connected by copper foil that is not coated with graphite material. The positive electrode sheet is cut and then falls on the corresponding negative electrode sheet.

[0060] It should be noted that because positive electrodes are less susceptible to dust loss than negative electrodes, the cutting process generates less debris and dust, which can reduce the impact of dust on the core pack. Furthermore, the cut positive electrodes are more uniform in size, making it easier for the positive electrodes to fall correctly onto the corresponding negative electrodes during cell assembly. This reduces the operational difficulty during assembly, improves production efficiency, and ensures production continuity.

[0061] Example 2

[0062] Different from the first embodiment, this embodiment discloses a method for preparing a laminated battery cell, which can be used to prepare the laminated battery cell of the first embodiment, and specifically includes the following steps:

[0063] Preparation step 1 of the first pole piece 14: First, a plurality of coating regions 11 are formed on a whole first current collector 10 by partitioning, and the plurality of coating regions 11 are spaced apart, and a spacer region 12 is provided between two adjacent coating regions 11 .

[0064] Step 2 for preparing the first electrode 14: a uniform thickness of the first active material 13 is coated on each coating area 11. After each coating area 11 is coated with the first active material 13, a first electrode 14 is formed. Two adjacent first electrode sheets 14 are connected by a spacer area 12 that is not coated with the first active material 13.

[0065] Step 1 for preparing the second electrode sheet 22 : continuously coating the second active material 21 on a whole piece of the second current collector 20 .

[0066] Step 2 of preparing the second pole piece 22 : cutting the second current collector 20 coated with the second active material 21 into a plurality of second pole pieces 22 .

[0067] Step 1 of preparing the battery cell: Compound the diaphragm 30 on both sides of multiple first pole pieces 14 and the spacer area 12, then detect the position of the first pole piece 14, and place the second pole piece 22 on the corresponding first pole piece 14, wherein a first pole piece 14 and the second pole piece 22 placed thereon and the diaphragm 30 form a unit piece 40.

[0068] Cell preparation step 2: folding the spacer 12 so that the unit cells 40 are stacked to prepare a laminated cell.

[0069] Based on this step, more specifically, during the preparation of the first electrode sheet 14, a plurality of coating regions 11 can be formed on the surface of the first current collector 10 through a specific process, such as screen printing, coating molds, or photolithography. These coating regions 11 are evenly distributed, and a spacer 12 is left between adjacent coating regions 11. The width of the spacer 12 and the size of the coating region 11 are both set according to the design specifications of the battery cell.

[0070] After the first current collector 10 is divided into coating areas 11, the first active material 13 is coated on each coating area 11. Existing coating equipment, such as a slit coater, is used to ensure that the first active material 13 is coated on the coating area 11 with a uniform thickness.

[0071] After each coating area 11 is coated with the first active material 13, the coating areas 11 and the active material thereon together constitute a first electrode 14. Two adjacent first electrode sheets 14 are connected by a spacer area 12 not coated with the first active material 13, forming a continuous first electrode sheet 14 structure.

[0072] During the preparation of the second pole piece 22 , a whole second current collector 20 is selected and the second active material 21 is continuously coated on its surface. The second current collector 20 coated with the second active material 21 is then cut into a plurality of second pole pieces 22 using a cutting device 80 .

[0073] During the preparation of the battery cell, the diaphragm 30 can be composited onto the first pole pieces 14 and the spacer 12. Specifically, the diaphragm 30 can be composited onto both sides of the first pole pieces 14 and the spacer 12 by thermal bonding or adhesive bonding.

[0074] After the diaphragm 30 is assembled, high-precision inspection equipment, such as a laser displacement sensor or a visual inspection system, is used to accurately inspect the position of the first pole piece 14. Based on the inspection results, the second pole piece 22 is accurately positioned on the corresponding first pole piece 14. Then, another first pole piece 14 is assembled with the second pole piece 22 and the diaphragm 30 to form a unit cell 40.

[0075] After the assembly of the cells 40 is completed, the cell 40 at the front is moved downward, and then as the following cells 40 are assembled and transported, the next cell 40 is stacked on the previous cell 40. Since the first pole pieces 14 in two adjacent cell pieces 40 are connected by the spacer 12, the multiple cell pieces 40 will fall naturally under the action of gravity, and the subsequent cell piece 40 will be stacked on the previous cell piece 40. When the predetermined number of cells 40 is reached, the movement of the first pole piece belt 53 and the falling of the second pole piece 22 are stopped.

[0076] Finally, the formed laminated battery cells are compacted and packaged as a whole. A hot pressing process is used to tightly combine the internal layers of the battery cells. The battery cells are then sealed with packaging materials such as aluminum-plastic film to ensure that the battery cells have good stability and safety during subsequent use.

[0077] Therefore, when preparing the first electrode sheets 14 in the laminated cell manufacturing method of this embodiment, adjacent first electrode sheets 14 are connected by the uncoated spacer 12 to form a continuous structure, avoiding the traditional cutting process. Because the short sides of the first electrode sheets 14 are no longer disconnected, the spacer 12 can provide tension and support during folding, thereby improving the alignment of the core package.

[0078] At the same time, since the first pole piece 14 does not need to be cut, dust generation can be reduced, the probability of safety hazards such as short circuit caused by dust entering the core package is reduced, and defects such as burrs and cracks on the edge of the pole piece due to cutting are avoided.

[0079] As a preferred technical solution of the present application, the first active material 13 is coated on both sides of the coating area 11, and the first electrode 14 is formed after the first active material 13 is coated on both sides of each coating area 11; the second active material 21 is continuously coated on both sides of the second current collector 20.

[0080] Thus, coating the first active material 13 on both sides of the coating area 11 significantly increases the total amount of active material on the first electrode 14 compared to coating only on one side. Similarly, continuously coating the second active material 21 on both sides of the second current collector 20 significantly increases the active material loading on the second electrode 22.

[0081] At the same time, double-sided coating makes the first and second pole pieces 14 and 22 more structurally symmetrical. With traditional single-sided coating, there are certain differences in the physical and chemical properties of the two sides of the pole piece. These differences can cause inconsistent deformation, expansion, and other phenomena during the charge and discharge cycles of the battery cell. Double-sided coating technology, however, makes the pole pieces more uniform and symmetrical in thickness and active material distribution, greatly improving their structural stability.

[0082] As a preferred technical solution of the present application, the area of one side of the coating region 11 is the same as the area of one side of the second pole piece 22 .

[0083] During the battery cell preparation process, a first electrode piece 14, a second electrode piece 22 placed thereon, and a diaphragm 30 form a unit cell 40. When the coating area 11 and the second electrode piece 22 have the same area, the second electrode piece 22 can be placed more accurately on the coating area 11 of the first electrode piece 14 when assembling the unit cell 40. For example, in automated assembly equipment, the visual inspection system can more easily identify and locate the edges of the electrode pieces, ensuring that the second electrode piece 22 is fully aligned with the coating area 11 of the first electrode piece 14, and the deviation can be controlled within a small range. This high-precision assembly can ensure the consistency of the internal structure of the battery cell, reduce the risk of internal short circuits caused by electrode misalignment, and improve the safety and reliability of the battery cell.

[0084] As a preferred technical solution of the present application, a plurality of coating regions 11 and spacer regions 12 are arranged along the length direction of the first current collector 10, so that a plurality of first pole pieces 14 are spaced apart along the length direction of the first current collector 10. The second pole piece 22 is located on one side or both sides of the first pole piece 14, and one first pole piece 14, one or two second pole pieces 22 located thereon, and the diaphragm 30 form a unit cell 40.

[0085] In this way, when multiple first electrode sheets 14 are spaced apart along the length of the first current collector 10, the short sides of two adjacent first electrode sheets 14 are connected by the spacer 12. The copper foil in the spacer 12 can pull and support the two electrode sheets. When two unit sheets 40 are stacked, the alignment of the short sides of the two first electrode sheets 14 can be improved.

[0086] As a preferred technical solution of the present application, two unit sheets 40 adjacently arranged in the length direction of the first current collector 10 are folded along the spacer 12 so that each unit sheet 40 is stacked in the thickness direction of the first current collector 10 .

[0087] Thus, by folding adjacent unit sheets 40 along the spacer 12 and stacking them in the thickness direction of the first current collector 10, a compact and orderly structure is formed within the cell. The unit sheets 40 are bonded to each other, effectively resisting the stress caused by the expansion and contraction of the electrode material during charge and discharge.

[0088] Example 3

[0089] This embodiment discloses a pole piece structure, which includes the first pole piece assembly of the first embodiment.

[0090] See Figure 1The first electrode assembly includes a first current collector 10 and a first active material 13. Specifically, the first current collector 10 is provided with a plurality of coating areas 11, and a spacer area 12 is provided between two adjacent coating areas 11. The first active material 13 is provided on the coating area 11, and the coating area 11 and the first active material 13 thereon form a first electrode 14, and two adjacent first electrode sheets 14 are connected by the spacer area 12.

[0091] The first current collector 10 may be copper foil or aluminum foil, and the first active material 13 coated on the coating area 11 thereof may be graphite or lithium cobalt oxide.

[0092] The first electrode sheet assembly of the present application does not require cutting and is directly supplied in a continuous manner. Since the first current collector 10 has a certain degree of ductility and rigidity, it can bend and fold during the lamination process of two adjacent first electrode sheets 14 and the electrode sheet of opposite polarity above them, while providing support, reducing deformation of the electrode sheets, maintaining the flatness of the electrode sheets, and making alignment more accurate.

[0093] In addition, during the stacking process, the continuous first pole piece assembly can ensure that the first pole piece assembly enters the stacking area stably and accurately through high-precision unwinding, tension control and guiding devices, and is precisely stacked with the pole pieces of opposite polarity, which greatly improves the accuracy of stacking, avoids scrapping due to poor entry, and improves production efficiency and product quality.

[0094] Example 4

[0095] See Figure 4 This embodiment also discloses a laminated battery cell preparation device for preparing the laminated battery cell as described in the first embodiment above, which includes an unwinding mechanism. Specifically, the unwinding mechanism includes a first unwinding assembly 50, a diaphragm unwinding assembly 60, and a second unwinding assembly 70. The first unwinding assembly 50 is used to unwind the first electrode strip 53 and pull the first electrode strip 53 to the first and second composite positions in sequence. The diaphragm unwinding assembly 60 is used to unwind the diaphragm 30 strip and pull the diaphragm 30 strip to the first composite position. The second unwinding assembly 70 is used to unwind the second electrode strip 73 and pull the second electrode strip 73 to the cutting position and the second composite position in sequence.

[0096] It should be noted that the first electrode strip 53 is the first electrode assembly of Example 1, and the first electrode assembly is supplied in the form of an electrode roll; the second electrode strip 73 is made by the first step of preparing the second electrode 22 of Example 2, and is supplied in the form of an electrode roll; the diaphragm 30 strip is also supplied in the form of an electrode roll.

[0097] In addition, a cutting device 80 and a pressing mechanism are provided. The cutting device 80 is disposed at the cutting position and is used to cut the second electrode strip 73 into a plurality of second electrode sheets 22. The pressing mechanism includes a first pressing assembly 90 and a second pressing assembly 100. The first pressing assembly 90 is disposed at the first combining position and is used to press and combine the diaphragm 30 and the first electrode strip 53. The second pressing assembly 100 is disposed at the second combining position and is used to press and combine the second electrode sheets 22, the first electrode strip 53, and the diaphragm 30.

[0098] Based on this structure, when using the laminated cell manufacturing equipment of this embodiment, the first electrode strip 53 can be unwound by the first unwinding assembly 50 and pulled to the first composite position. At the same time, the diaphragm unwinding assembly 60 unwinds the diaphragm 30 strip and pulls it to the first composite position. At the first composite position, the two laminating rollers of the first pressing assembly 90 are arranged opposite each other in the height direction and spaced apart to form a first composite gap. The first electrode strip 53 and the diaphragm 30 strips on both sides enter the first composite gap and are pressed together under the rotation and lamination of the two laminating rollers. Then, the first electrode strip 53 and the diaphragm 30 strips on both sides are pulled forward to the next workstation.

[0099] Subsequently, the second electrode sheet tape 73 is unwound by the second unwinding assembly 70. At this time, the second electrode sheet tape 73 is the second current collector 20 continuously coated with the second active material 21. The second unwinding assembly 70 pulls it to the cutting station. At the cutting station, the cutting device 80 cuts the second current collector 20 continuously coated with the second active material 21 into a plurality of second electrode sheets 22 of the same size. The second electrode sheets 22 are then dropped one by one onto both sides of each first electrode sheet 14 on the first electrode sheet tape 53. The first electrode sheet 14 and the second electrode sheet 22 thereon form a unit sheet 40.

[0100] Subsequently, the unit cell 40 will be transported to the second composite position, where the two rolling rollers of the second pressing assembly 100 are arranged relative to each other in the height direction and spaced apart to form a second composite gap. The unit cell 40 enters the second composite gap and is pressed together under the rotation and rolling of the two rolling rollers. Then the unit cell 40 continues to be pulled forward to the stacking table 120. Since the adjacent unit cells 40 are connected by the spacing area 12 of the first electrode strip 53, which is copper foil, multiple unit cells 40 can be stacked in sequence on the stacking table 120 to form a stacked battery cell.

[0101] A detection station is provided between the cutting station and the second composite station. A detection device 80 is provided at the detection station. The detection device 80 may be a CCD. The detection device 80 confirms the position of the first pole piece 14 by taking a picture, thereby determining the position where the second pole piece 22 needs to be registered, ensuring that the second pole piece 22 can accurately fall on the corresponding first pole piece 14. Furthermore, the detection device 80 may also be a position sensor.

[0102] In addition, the first unwinding assembly 50 includes a first driving member, a first mounting shaft 51 and a first traction wheel 52. The first mounting shaft 51 is used to install the first pole piece belt 53 roll. The first driving member can be a motor, which is used to drive the first mounting shaft 51 to rotate so that the first mounting shaft 51 unwinds the first pole piece belt 53, and the first traction wheel 52 is used to pull the first pole piece belt 53 to move during the rotation process.

[0103] The second unwinding assembly 70 includes a second driving member, a second mounting shaft 71 and a second traction wheel 72. The second mounting shaft 71 is used to install the second pole piece belt 73. The second driving member can be a motor, which is used to drive the second mounting shaft 71 to rotate so that the second mounting shaft 71 drives the member to unwind the second pole piece belt 73, and the second traction wheel 72 is used to pull the second pole piece belt 73 to move during the rotation process.

[0104] The diaphragm unwinding assembly 60 includes a third driving member, a third mounting shaft 61 and a third traction wheel 62. The third mounting shaft 61 is used to install the diaphragm 30 roll. The third driving member can be a motor, which is used to drive the third mounting shaft 61 to rotate so that the third mounting shaft 61 driving member unwinds the diaphragm 30 belt.

[0105] Therefore, due to the use of a continuous first electrode sheet assembly, when the electrode sheet of the first electrode sheet assembly is a negative electrode sheet, the laminated cell preparation equipment of this embodiment does not require a negative electrode cutting tool or laser, nor does it require a reserved space on the equipment for cutting the first electrode sheet 14. The entire equipment occupies a small space and has a compact structure. At the same time, since the first electrode sheet 14 does not need to be cut, it does not generate dust, and the corresponding dust removal equipment can be eliminated accordingly.

[0106] The technical means disclosed in the present application are not limited to those disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above-mentioned technical features. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of the present application, and such improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A laminated battery cell, characterized in that: include, A first pole piece assembly includes a first current collector and a first active material, wherein the first current collector is provided with a plurality of coating areas, and a spacer area is provided between two adjacent coating areas; the coating areas are provided with the first active material, and the coating areas and the first active material thereon form a first pole piece, and two adjacent first pole pieces are connected by the spacer area; a diaphragm, comprising a first diaphragm and a second diaphragm, wherein the first diaphragm and the second diaphragm are respectively disposed on both sides of the first pole piece and the spacer area; The second pole piece assembly includes a plurality of second pole pieces, wherein the second pole pieces are arranged on a side of the first diaphragm facing away from the first pole piece and on a side of the second diaphragm facing away from the first pole piece.

2. The laminated battery cell according to claim 1, characterized in that: The orthographic projection of the second pole piece on the diaphragm coincides with the orthographic projection of the first pole piece on the diaphragm.

3. The laminated battery cell according to claim 1, wherein: The second pole piece includes a second current collector and a second active material, and the second active material is continuously disposed on the second current collector.

4. The laminated battery cell according to any one of claims 1 to 3, characterized in that: The first electrode is a negative electrode, and the second electrode is a positive electrode.

5. A method for preparing a laminated battery core, for preparing the laminated battery core according to any one of claims 1 to 4, characterized in that: The steps include: First pole piece preparation step 1: forming a plurality of coating areas on a whole first current collector, separating the plurality of coating areas, and providing a spacing area between two adjacent coating areas; First electrode sheet preparation step 2: coating the first active material on each of the coating areas to form a first electrode sheet after coating each of the coating areas with the first active material, and connecting two adjacent first electrode sheets with the spacer area; Second pole piece preparation step 1: continuously coating the second active material on a whole second current collector; Second pole piece preparation step 2: cutting the second current collector coated with the second active material into a plurality of second pole pieces; Cell preparation step 1: Compounding a diaphragm on both sides of the plurality of first pole pieces and the spacer area; detecting the position of the first pole pieces, and placing the second pole piece on the corresponding first pole piece, so that one first pole piece, the second pole piece placed thereon, and the diaphragm form a unit cell; The second step of preparing the battery cell is to continuously stack the unit sheets in a zigzag path to prepare a stacked battery cell.

6. The method for preparing a laminated battery core according to claim 5, wherein: The first active material is coated on both sides of the coating area, and the first pole piece is formed after the first active material is coated on both sides of each coating area; the second active material is continuously coated on both sides of the second current collector.

7. The method for preparing a laminated battery core according to claim 5 or 6, wherein: The area of one side of the coating region is the same as the area of one side of the second pole piece.

8. The method for preparing a laminated battery core according to claim 7, wherein: A plurality of coating areas and a plurality of spacing areas are partitioned along the length direction of the first current collector so that a plurality of first pole pieces are spaced apart along the length direction of the first current collector; the second pole piece falls on one side or both sides of the first pole piece, and one first pole piece and one or two second pole pieces and a diaphragm falling thereon form a unit piece.

9. The method for preparing a laminated battery core according to claim 8, wherein: Two unit sheets adjacent to each other in the length direction of the first current collector are folded along the spacer, so that each unit sheet is stacked in the thickness direction of the first current collector.

10. A pole piece structure, characterized in that: Comprising the first pole piece assembly as described in claim 1.

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