Battery cell preparation system, battery cell preparation method, stacked battery cell and battery

Abstract

The present invention provides a battery cell preparation system, a battery cell preparation method, a stacked battery cell and a battery. The battery cell preparation system includes a conveying mechanism, a positioning member, a roller group for conveying a diaphragm, and a stacking table arranged below the roller group. The diaphragm is partially laid on the stacking table, and the diaphragm can be folded when the stacking table switches between a first stacking position and a second stacking position. The conveying mechanism is used to convey the first pole piece to the diaphragm stacked on the stacking table above the first stacking position, and to convey the second pole piece to the diaphragm stacked on the stacking table above the second stacking position. The positioning member can move between a first auxiliary position and a second auxiliary position, and the positioning member located at any auxiliary position is attached to the surface of the diaphragm facing away from the stacking table from one side of the diaphragm to the other side along the width direction, and is used to fix relative to the stacking table to support the diaphragm during the stacking position switching process of the stacking table, and move to the corresponding auxiliary position when the stacking position switching of the stacking table is completed and the first pole piece or the second pole piece is stacked on the diaphragm.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a battery cell preparation system, a battery cell preparation method, a stacked battery cell and a battery. Background Art

[0002] In recent years, new energy vehicles have been welcomed by users due to their advantages such as energy saving and environmental protection. Among them, the power battery pack is the core energy source of new energy vehicles, providing driving power for the entire vehicle. In the related technology, when making a power battery pack, the preparation method of the battery cells in its single battery mainly adopts a "Z"-shaped stacking scheme, specifically: the pressure claws press the opposite ends of the diaphragm in the width direction, and the stacking platform or the feed roller group is replaced, so that the diaphragm is in a "Z" shape to separate the alternately stacked positive and negative plates in sequence, thereby obtaining a stacked battery cell with a continuous diaphragm.

[0003] However, the force clamping points of the diaphragm during the lamination process are only at the two opposite ends along the width length direction, while the part between the two opposite ends along its own width direction is not subject to positioning constraints. When the diaphragm is folded back and forth in a "Z" shape, the part of the diaphragm that is not subject to positioning constraints is prone to wrinkles, collapse, bulging and other problems, which will affect the quality of the battery cell. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a battery cell preparation system, a battery cell preparation method, a stacked battery cell and a battery. When the battery cell preparation system is used to prepare the stacked battery cell of the battery, a positioning member can be used to fit the diaphragm from one side to the other side in the width direction of the diaphragm, so as to support and completely position and constrain the diaphragm during the lamination process, ensuring that the diaphragm does not have wrinkles, collapse, bulges, etc. when it is folded back and forth in a "Z" shape, which is conducive to improving the quality of the stacked battery cell.

[0005] In order to achieve the above objectives, in a first aspect, the present invention provides a battery cell preparation system, comprising:

[0006] Roller set for transporting the diaphragm;

[0007] A stacking platform is arranged below the roller group, a portion of the diaphragm adjacent to one end thereof close to the stacking platform is laid on the stacking platform, the stacking platform and / or the roller group can be moved in a horizontal direction to switch the stacking platform between a first stacking position and a second stacking position, the first stacking position and the second stacking position are respectively located below opposite sides of the roller group in a horizontal direction, and the diaphragm can be folded when the stacking position of the stacking platform is switched;

[0008] A transport mechanism, used for transporting a first pole piece to be stacked on the diaphragm above the stacking platform located at the first stacking position, and transporting a second pole piece to be stacked on the diaphragm above the stacking platform located at the second stacking position, wherein the first pole piece and the second pole piece have opposite polarities, are alternately stacked and separated by the diaphragm;

[0009] A positioning mechanism, comprising a positioning member extending along the width direction of the diaphragm; when the first pole piece is stacked on the diaphragm, the positioning member can be moved to a first auxiliary position located on a side of the first pole piece close to the roller group; when the second pole piece is stacked on the diaphragm, the positioning member can be moved to a second auxiliary position located on a side of the second pole piece close to the roller group;

[0010] Among them, when the positioning member is located at any of the auxiliary positions, it is attached to the surface of the diaphragm facing away from the stacking table from one side of the diaphragm to the other side along the width direction. The positioning member is used to be fixed relative to the stacking table to support the diaphragm when the stacking table switches the stacking position, and moves to the first auxiliary position or the second auxiliary position when the stacking table completes the stacking position switching and the first pole piece or the second pole piece is stacked on the diaphragm.

[0011] In a second aspect, the present invention further provides a method for preparing a battery cell, which is applied to the battery cell preparation system as described above, and the method for preparing a battery cell comprises:

[0012] Providing a diaphragm and conveying it through a roller set, laying a portion of the diaphragm adjacent to an end thereof close to a lamination table on the lamination table;

[0013] Placing the lamination table at a first lamination position below one side of the roller group in the horizontal direction, and conveying the first pole piece to the diaphragm stacked on the lamination table by a conveying mechanism, and then lifting the conveying mechanism;

[0014] Controlling the positioning member to move to a first auxiliary position located on a side of the first pole piece close to the roller group, the positioning member being attached to a surface of the diaphragm facing away from the lamination table from one side to the other side along the width direction of the diaphragm;

[0015] The stacking platform is switched from the first stacking position to the second stacking position located below the other side of the roller group in the horizontal direction, and the second pole piece is transported to the diaphragm stacked on the stacking platform by the transport mechanism, and then the transport mechanism is lifted, and the positioning member fixes and supports the diaphragm relative to the stacking platform when the stacking platform is switched from the first stacking position to the second stacking position; wherein the second pole piece has opposite polarity to the first pole piece;

[0016] Control the positioning member to move to a second auxiliary position located on a side of the second pole piece close to the roller group, and the positioning member is attached to a surface of the diaphragm facing away from the lamination table from one side to the other side along the width direction of the diaphragm;

[0017] The stacking platform is switched from the second stacking position to the first stacking position, and the positioning member fixes and supports the diaphragm relative to the stacking platform when the stacking platform is switched from the second stacking position to the first stacking position;

[0018] Repeat the stacking steps of the first pole sheet and the second pole sheet until the required plurality of the first pole sheets and the second pole sheets are alternately stacked, and each adjacent first pole sheet and second pole sheet are separated by the diaphragm, so as to obtain a stacked battery cell.

[0019] In a third aspect, the present invention provides a stacked battery cell, wherein the stacked battery cell is manufactured using the battery cell manufacturing method as described above.

[0020] In a fourth aspect, the present invention provides a battery, comprising the above-mentioned stacked battery cell.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the battery cell preparation system is provided with a positioning piece which can be switched between a first auxiliary position and a second auxiliary position, the positioning piece extends along the width direction of the diaphragm, and when the positioning piece is located at any of the auxiliary positions, it is attached to the surface of the diaphragm facing away from the stacking table from one side of the diaphragm to the other side along the width direction, and the positioning piece can support and completely position and restrain the diaphragm during the stacking process, ensuring that the diaphragm does not have wrinkles, collapse, bulging and other problems when it is folded back and forth in a "Z" shape, which is beneficial to improving the quality of the manufactured stacked battery cells.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a structural schematic diagram of a battery cell preparation system provided by an embodiment of the present invention when the stacking table is located at the first stacking position and the positioning member is located at the second auxiliary position.

[0025] Figure 2 yes Figure 1 The structure diagram of the battery cell preparation system shown is when the lamination table is located at the second lamination position and the positioning member is located at the first auxiliary position.

[0026] Figure 3 It is a schematic structural diagram of a stacked battery cell provided in one embodiment of the present invention.

[0027] Figure 4 It is a flow chart of a method for preparing a battery cell provided in one embodiment of the present invention.

[0028] Figures 5 to 13 It is a schematic diagram of the use process of the battery cell preparation system provided in one embodiment of the present invention for preparing stacked battery cells.

[0029] Description of main component symbols:

[0030] Battery cell preparation system 1

[0031] Stacked battery 2

[0032] The first pole piece 10

[0033] The second pole piece 20

[0034] Diaphragm 30

[0035] Roller set 40

[0036] First nip roller 41

[0037] Second nip roller 42

[0038] Stacking table 50

[0039] Transport mechanism 60

[0040] Positioning piece 70

[0041] Pressing claw mechanism 80

[0042] The first pressing claw 81

[0043] Second pressing claw 82

[0044] The following specific implementation modes will further illustrate the present invention in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0045] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0046] Please also read Figures 1 to 3The present invention provides a battery cell preparation system 1 for preparing a stacked battery cell 2. Figure 3 As shown, the stacked battery cell 2 includes a plurality of first pole sheets 10 and second pole sheets 20 alternately stacked in sequence, and a separator 30 is provided between adjacent first pole sheets 10 and second pole sheets 20. The first pole sheets 10 and the second pole sheets 20 have opposite polarities, and the first pole sheets 10 and the second pole sheets 20 can be a positive pole sheet and a negative pole sheet, respectively, or a negative pole sheet and a positive pole sheet, respectively, without limitation.

[0047] like Figure 1 and Figure 2 As shown, the battery cell preparation system 1 includes a roller group 40, a lamination table 50, a transport mechanism 60 and a positioning mechanism. Figure 1 and Figure 2 Only the positioning member 70 in the positioning mechanism is shown, and other components in the positioning mechanism are not shown.

[0048] Specifically, the roller set 40 is used to transport the diaphragm 30. Figure 1 and Figure 2 In one embodiment shown, the roller group 40 includes a first clamping roller 41 and a second clamping roller 42 arranged in parallel in the horizontal direction, and there is a gap between the first clamping roller 41 and the second clamping roller 42 for the diaphragm 30 to pass through. The first clamping roller 41 and the second clamping roller 42 clamp the diaphragm 30, and when at least one of the first clamping roller 41 and the second clamping roller 42 rolls, the diaphragm 30 can be transported to achieve the feeding of the diaphragm 30 when the first pole piece 10 and the second pole piece 20 are stacked. Optionally, in one embodiment of the present invention, an elastic protective layer can be provided on the outer surface of the first clamping roller 41 and the second clamping roller 42, and the elastic protective layer can prevent the roller group 40 from damaging the diaphragm 30 when transporting the diaphragm 30. Also optionally, in one embodiment of the present invention, the diaphragm 30 can be provided by a diaphragm roll, which is sleeved on a rotating shaft and the free end of the diaphragm roll passes through the first clamping roller 41 and the second clamping roller 42. When at least one of the first clamping roller 41 and the second clamping roller 42 rolls, the diaphragm roll and the rotating shaft can be pulled to rotate, thereby realizing the feeding of the diaphragm 30.

[0049] The lamination platform 50 is disposed below the roller group 40, and a portion of the diaphragm 30 adjacent to one end thereof close to the lamination platform 50 is laid on the lamination platform 50. Figure 1 and Figure 2In one embodiment shown, the diaphragm 30 can be laid on the upper surface of the lamination platform 50 by blowing and sucking. Specifically, the diaphragm 30 can be blown onto the lamination platform 50 first, and then the diaphragm 30 can be sucked and positioned by an adsorption mechanism (not shown) provided on the lamination platform 50, so that the diaphragm 30 can be laid flat on the lamination platform 50. In other embodiments, the diaphragm 30 can also be laid on the lamination platform 50 by other methods, for example, the diaphragm 30 can be pressed on the lamination platform 50 by some detachable fixing parts (such as magnetic parts), as long as the fixing parts do not affect the subsequent lamination of the first pole piece 10 and the second pole piece 20, which will not be described in detail.

[0050] like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, the stacking platform 50 and / or the roller group 40 can be moved in the horizontal direction to switch the stacking platform 50 between the first stacking position and the second stacking position. The first stacking position and the second stacking position are respectively located below the opposite sides of the roller group 40 in the horizontal direction. Figure 1 and Figure 2 In one embodiment shown, in order to ensure smooth feeding of the diaphragm 30, the roller group 40 is fixed, and the stacking platform 50 moves in the horizontal direction relative to the roller group 40, thereby switching between the first stacking position and the second stacking position; in this embodiment, the first stacking position is located at the lower right side of the roller group 40 in the horizontal direction, and the second stacking position is located at the lower left side of the roller group 40 in the horizontal direction. In other embodiments, the first stacking position may be located at the lower left side of the roller group 40 in the horizontal direction, and the second stacking position is located at the lower right side of the roller group 40 in the horizontal direction. It can be understood that when the stacking platform 50 switches between the first stacking position and the second stacking position, the diaphragm 30 will be reciprocatedly folded. Specifically, when the stacking platform 50 moves and switches from the first stacking position to the second stacking position, the diaphragm 30 points toward the second stacking position in the direction of the first stacking position ( Figure 2 When the stacking platform 50 is moved from the second stacking position to the first stacking position, the diaphragm 30 is directed toward the direction of the first stacking position toward the second stacking position ( Figure 1The diaphragm 30 is folded in the left direction as shown in the figure, and after the stacking station 50 switches the stacking position for multiple times, the diaphragm 30 can be reciprocally folded in a "Z" shape and stacked on the stacking station 50. In the embodiment of the present invention, the stacking station 50 can switch between the first stacking position and the second stacking position relative to the roller group 40 to achieve the stacking of the diaphragm 30, so the diaphragm 30 only needs to use one diaphragm unwinding mechanism (that is, the aforementioned rotating shaft with the diaphragm roll), which has a simple structure and low cost.

[0051] like Figure 1 As shown, the transport mechanism 60 is used to transport the first pole piece 10 to the diaphragm 30 above the lamination platform 50 at the first lamination position. After the transport mechanism 60 releases the first pole piece 10, the first pole piece 10 can be stacked on the diaphragm 30. Figure 2 As shown, the transport mechanism 60 is also used to transport the second pole piece 20 to the diaphragm 30 above the lamination platform 50 at the second lamination position. After the transport mechanism 60 releases the second pole piece 20, the second pole piece 20 can be stacked on the diaphragm 30. Figure 1 and Figure 2 It is illustrated that the conveying mechanism 60 conveys the first pole piece 10 and the second pole piece 20 to the top of the diaphragm 30, but does not release the first pole piece 10 and the second pole piece 20. It is not difficult to understand that after the stacking station 50 switches the stacking position multiple times, the conveying mechanism 60 can stack multiple first pole pieces 10 and multiple second pole pieces 20 on the diaphragm 30 that is folded back and forth in a "Z" shape, so that the first pole piece 10 and the second pole piece 20 are alternately stacked and separated by the diaphragm 30. In the present invention, the conveying mechanism 60 can be, but is not limited to, an existing conveying mechanism capable of conveying sheet objects, such as a manipulator, a suction plate or a suction cup, and no limitation is made to this. Figure 1 and Figure 2 In one embodiment shown, the transport mechanism 60 uses a suction plate or a suction cup to transport the electrode piece by adsorption, thereby avoiding damage to the electrode piece.

[0052] like Figure 1 and Figure 2As shown, the positioning mechanism includes a positioning member 70 extending along the width direction of the diaphragm 30 (i.e., perpendicular to the direction of the line connecting the first stacking position and the second stacking position), and the positioning member 70 can be switched between a first auxiliary position and a second auxiliary position to assist the diaphragm 30 in folding when the stacking position of the stacking platform 50 is switched. Specifically, when the first pole piece 10 is stacked on the diaphragm 30, the positioning member 70 can be moved to the first auxiliary position located on the side of the first pole piece 10 close to the roller group 40, at which time, the positioning member 70 is located between the roller group 40 and the first pole piece 10; when the second pole piece 20 is stacked on the diaphragm 30, the positioning member 70 can be moved to the second auxiliary position located on the side of the second pole piece 20 close to the roller group 40, at which time, the positioning member 70 is located between the roller group 40 and the second pole piece 20. The first auxiliary position and the second auxiliary position are respectively located above the opposite sides of the stacking platform 50 in the horizontal direction.

[0053] It should be noted that, in the embodiment of the present invention, the extension length of the positioning member 70 is greater than or equal to the width of the diaphragm 30, and the positioning member 70 is attached to the surface of the diaphragm 30 facing away from the stacking platform 50 from one side of the diaphragm 30 to the other side along the width direction when the diaphragm 30 is located in any of the auxiliary positions, and the positioning member 70 is fixed relative to the stacking platform 50 when the stacking position of the stacking platform 50 is switched. Figure 2 As shown, when the stacking platform 50 is switched from the first stacking position to the second stacking position, the positioning member 70 attached to the diaphragm 30 can support the diaphragm 30, thereby assisting the diaphragm 30 to fold in the direction from the second stacking position to the first stacking position; Figure 1 As shown, when the stacking station 50 switches from the second stacking position to the first stacking position, the positioning member 70 attached to the diaphragm 30 can also support the diaphragm 30, thereby assisting the diaphragm 30 to fold in the direction from the first stacking position to the second stacking position. In other words, the positioning member 70 located at any of the auxiliary positions is completely attached to the diaphragm 30 in the width direction of the diaphragm 30. When the stacking station 50 switches the stacking position, the positioning member 70 supports the diaphragm 30, so that the diaphragm 30 is completely positioned and constrained by the positioning member 70 in the width direction. Compared with the prior art in which the diaphragm is only positioned and constrained at the opposite ends in the width direction, the diaphragm 30 will not have wrinkles, collapse, bulges, etc. when it is folded back and forth in a "Z" shape, which is conducive to improving the quality of the manufactured stacked battery cell 2.

[0054] It should also be noted that, in an embodiment of the present invention, when the stacking table 50 completes a stacking position switch and the first pole piece 10 or the second pole piece 20 is stacked on the diaphragm 30, that is, after the positioning member 70 supports and assists the diaphragm 30 to complete a folding and a new pole piece is stacked on the diaphragm 30, the positioning member 70 can be moved to the first auxiliary position or the second auxiliary position accordingly, so as to support and assist the diaphragm 30 to perform the next folding when the stacking table 50 switches the stacking position again.

[0055] Optionally, in Figure 1 and Figure 2 In one embodiment shown, the positioning member 70 is made of an electrothermal material (not limited to metal materials such as copper and iron), and the positioning mechanism also includes a power supply (not shown in the figure), which is used to supply power to the positioning member 70 to heat the positioning member 70. When the stacking table 50 completes the stacking position switching and the first pole piece 10 or the second pole piece 20 is stacked on the diaphragm 30, the positioning member 70 is also used to energize and generate heat to melt the diaphragm 30, so that the positioning member 70 can be detached from the diaphragm 30 to facilitate movement to the corresponding first auxiliary position or the second auxiliary position. Preferably, in this embodiment, the positioning member 70 is provided with an anti-stick coating or an anti-stick layer composed of anti-stick elements such as an anti-stick sleeve (not shown in the figure) at least on the portion that is in contact with the diaphragm 30, so as to prevent slag from adhering to the positioning member 70 when the positioning member 70 melts the diaphragm 30, thereby ensuring that the surface of the positioning member 70 that is in contact with the diaphragm 30 is smooth, avoiding the occurrence of bulges on the portion where the diaphragm 30 and the positioning member 70 are in contact, and preventing the diaphragm 30 from being worn and broken by slag when being folded.

[0056] Of course, in other embodiments, the battery cell preparation system 1 may further include a cutter. When the stacking table 50 completes the stacking position switching and the first pole piece 10 or the second pole piece 20 is stacked on the diaphragm 30, the cutter is used to cut off the portion of the diaphragm 30 that is attached to the positioning member 70. It can also enable the positioning member 70 to be detached from the diaphragm 30 so as to move to the corresponding first auxiliary position or the second auxiliary position. This will not be elaborated herein.

[0057] In an embodiment of the present invention, the diaphragm 30 used to separate the adjacent first pole piece 10 and the second pole piece 20 is melted or cut, so that the diaphragm 30 in the finally manufactured stacked battery cell 2 is a discontinuous multi-layer diaphragm. Compared with the stacked battery cell with a continuous diaphragm in the prior art, the stacked battery cell 2 in the present invention is not covered by the diaphragm 30 on both sides in the width direction of the pole pieces, so that the wetting effect in the electrolyte is better, which helps to improve the product quality of the battery in which the stacked battery cell 2 is located.

[0058] Furthermore, in an embodiment of the present invention, the positioning mechanism further includes a mounting frame (not shown in the figure) and a driving member (not shown in the figure). The mounting frame is used to mount the positioning member 70; the driving member is used to control the movement of the positioning member 70 on the mounting frame, so that the positioning member 70 is fixed relative to the lamination table 50 when the lamination table 50 switches the lamination position, ensuring that the positioning member 70 can support and assist the diaphragm 30 in folding, and when the lamination table 50 completes the lamination position switching and the first pole piece 10 or the second pole piece 20 is stacked on the diaphragm 30, it can move relative to the lamination table 50 to the first auxiliary position or the second auxiliary position, thereby realizing the auxiliary position switching of the positioning member 70.

[0059] Optionally, in a possible implementation, the mounting frame is fixedly mounted on the lamination platform 50; when the lamination platform 50 switches the lamination position, the driving member is in a stopped state, and the mounting frame and the positioning member 70 follow the lamination platform 50 to move synchronously relative to the roller group 40, so that the positioning member 70 is fixed relative to the lamination platform 50; when the lamination platform 50 completes the lamination position switching and the first pole piece 10 or the second pole piece 20 is stacked on the diaphragm 30, the driving member is in a working state, and the driving member drives the positioning member 70 to move on the mounting frame, so that the positioning member 70 can move relative to the lamination platform 50 to the first auxiliary position or the second auxiliary position. By fixing the mounting frame on the lamination platform 50, the positioning member 70 can follow the lamination platform 50 to move synchronously relative to the roller group 40 when the lamination platform 50 switches the lamination position, thereby avoiding pulling the diaphragm 30 and preventing the diaphragm 30 from being torn or deformed. In other embodiments, the mounting frame may not be arranged on the stacking table 50. When the stacking table 50 switches the stacking position, the driving member drives the positioning member 70 to move on the mounting frame. The stacking table 50 and the positioning member 70 move synchronously. The positioning member 70 can also be fixed relative to the stacking table 50. This will not be elaborated herein.

[0060] It should be noted that, in any of the above embodiments, the movement of the positioning member 70 driven by the driving member on the mounting frame specifically includes horizontal movement and vertical movement. The horizontal movement is used to move the positioning member 70 from one side of the stacking platform 50 to the other side in the horizontal direction. The vertical movement is mainly to avoid the first pole piece 10, the second pole piece 20 and the pressure claw mechanism 80 (described later) when the positioning member 70 performs the horizontal movement, so as to prevent the positioning member 70 from colliding. The horizontal movement and the vertical movement can be performed simultaneously or in steps, as long as the positioning member 70 can be switched between the first auxiliary position and the second auxiliary position, which will not be described in detail.

[0061] The mounting frame and the driving member may adopt existing mounting frames and driving members such as cylinders, as long as the purpose of mounting the positioning member 70 and driving the positioning member 70 to move can be achieved, and there is no limitation on this.

[0062] Of course, in other embodiments, the positioning mechanism may also use other components (not limited to a multi-axis robotic arm) to control the movement of the positioning member 70, and this is not limited thereto.

[0063] Optionally, in an embodiment of the present invention, the cross-sectional shape of the positioning member 70 perpendicular to its extension direction may be, but is not limited to, oblate, circular or elliptical. The positioning member 70 has a smooth outer surface. When the positioning member 70 is attached to the diaphragm 30, the portion of the diaphragm 30 attached to the positioning member 70 will not experience stress concentration, thereby avoiding deformation or tearing of the diaphragm 30. The positioning member 70 may be rod-shaped or tubular. Figure 1 and Figure 2 In the illustrated embodiment, the positioning member 70 is a round rod-shaped positioning member made of copper.

[0064] Optionally, in an embodiment of the present invention, the battery cell preparation system 1 further includes a cleaning mechanism (not shown in the figure), which is used to clean the positioning member 70, specifically, to clean the positioning member 70 before the positioning member 70 is attached to the diaphragm 30, to ensure that the surface of the positioning member 70 is clean and free of dirt (such as the aforementioned slag or debris generated when the cutter cuts the diaphragm 30), to avoid bulges on the part of the diaphragm 30 attached to the positioning member 70, and to prevent the diaphragm 30 from being worn and broken by dirt when folding. The cleaning mechanism can be a water gun that uses water to rinse the positioning member 70, and the positioning member 70 can be wiped dry after washing with water before attaching the diaphragm 30. The cleaning mechanism can also be an air gun that uses wind to wash the positioning member 70, and there is no limitation on this.

[0065] Further, please refer again to Figure 1 and Figure 2 In one embodiment of the present invention, the battery cell preparation system 1 further includes a pressing claw mechanism 80, and the pressing claw mechanism 80 includes a first pressing claw 81 and a second pressing claw 82. The first pressing claw 81 is used to press the first pole piece 10 when the first pole piece 10 is stacked on the diaphragm 30, and the second pressing claw 82 is used to press the second pole piece 20 when the second pole piece 20 is stacked on the diaphragm 30. In this embodiment, when the stacking table 50 is stacking, the first pole piece 10 and the second pole piece 20 that are alternately stacked are pressed by the first pressing claw 81 and the second pressing claw 82, respectively, which can not only ensure that any of the pole pieces is always in a pressed state during the stacking process to prevent the pole pieces from shifting, but also avoid cross-contamination of active materials on pole pieces of different polarities, which is helpful to improve the quality of the stacked battery cell 2.

[0066] It should be noted that the plurality of first pole pieces 10 and the plurality of second pole pieces 20 are alternately stacked in sequence, so the first pressing claw 81 and the second pressing claw 82 need to release the pressing effect on the pole piece in a timely manner after pressing a corresponding pole piece, so as to be used to press the corresponding next pole piece.

[0067] Optionally, in an embodiment of the present invention, at the same time or after the second pole piece 20 is stacked on the first pole piece 10 pressed by the first pressing claw 81 and the second pole piece 20 is pressed by the second pressing claw 82, the first pressing claw 81 is withdrawn from between the first pole piece 10 and the second pole piece 20, thereby releasing the pressing effect on the first pole piece 81 and being in a waiting state, in preparation for pressing the other first pole piece 10 when another first pole piece 10 is stacked on the second pole piece 20; or, after the second pole piece 20 and another first pole piece 10 are stacked on the first pole piece 10 pressed by the first pressing claw 81, the first pressing claw 81 is withdrawn from between the first pole piece 10 and the second pole piece 20, and the first pressing claw 81 does not need to wait and is directly used to press the other first pole piece 10.

[0068] Similarly, at the same time or after the first pole piece 10 is stacked on the second pole piece 20 pressed by the second pressing claw 82 and the first pole piece 10 is pressed by the first pressing claw 81, the second pressing claw 82 is withdrawn from between the second pole piece 20 and the first pole piece 10, so as to be ready to compress the other second pole piece 20 when another second pole piece 20 is stacked on the first pole piece 10, or, after the first pole piece 10 and another second pole piece 20 are stacked on the second pole piece 20 pressed by the second pressing claw 82, the second pressing claw 82 is withdrawn from between the second pole piece 20 and the first pole piece 10, so as to be used to compress the other second pole piece 20. In the embodiment of the present invention, the first pressing claw 81 and the second pressing claw 82 respectively have two different withdrawal modes, and different matching schemes can be adopted to timely release the pressing effect on the corresponding pole piece, which has high flexibility in use.

[0069] It should also be noted that, in the embodiments of the present invention, any of the pressure claws preferably adopts a flat plate structure with a relatively thin thickness. When the diaphragm 30 is folded and stacked with any of the pole pieces, the diaphragm 30 covers the corresponding pressure claw together. The portion of the diaphragm 30 covering the pressure claw will produce a slight bulge. When the pressure claw is pulled out, the portion of the diaphragm 30 covering the pressure claw will collapse to a certain extent. As long as the thickness of the pressure claw is reasonably controlled, it can be ensured that the collapsed portion of the diaphragm 30 has little or no effect on the manufactured stacked battery cell 2.

[0070] See also Figure 4 The present invention also provides a method for preparing a battery cell, which is used in the battery cell preparation system 1 in any of the above embodiments to prepare Figure 3 The stacked battery cell 2 shown. Figure 4 As shown, the battery cell preparation method includes multiple steps from step S1 to step S7. Figures 5 to 13 , steps S1 to S7 are described.

[0071] Step S1, see Figure 5 , a diaphragm 30 is provided and transported by a roller set 40 , and a portion of the diaphragm 30 adjacent to one end thereof close to a lamination table 50 is laid on the lamination table 50 .

[0072] Step S2, such as Figure 5 As shown, the lamination platform 50 is placed in the first lamination position below one side of the roller group 40 in the horizontal direction, and is transported by the transport mechanism 60 (see Figure 1 ) transport the first pole piece 10 to the diaphragm 30 stacked on the lamination table 50, and then lift the transport mechanism 60.

[0073] Step S3, such as Figure 5As shown, the positioning member 70 is controlled to move to the first auxiliary position located on the side of the first pole piece 10 close to the roller group 40, and the positioning member 70 is attached to the surface of the diaphragm 30 facing away from the lamination table 50 from one side to the other side along the width direction of the diaphragm 30. At this time, the positioning member 70 is located between the first pole piece 10 and the roller group 40.

[0074] Step S4, please refer to Figures 6 to 8 , the stacking platform 50 is switched from the first stacking position to the second stacking position located below the other side of the roller group 40 in the horizontal direction, and the second pole piece 20 is transported to the diaphragm 30 stacked on the stacking platform 50 by the transport mechanism 60, and then the transport mechanism 60 is lifted, and the positioning member 70 fixes and supports the diaphragm 30 relative to the stacking platform 50 when the stacking platform 50 is switched from the first stacking position to the second stacking position. The second pole piece 20 and the first pole piece 10 have opposite polarities, and the first pole piece 10 and the second pole piece 20 can be a positive pole piece and a negative pole piece, respectively, or a negative pole piece and a positive pole piece, respectively, without limitation.

[0075] It can be understood that when the stacking platform 50 is moved from the first stacking position to the second stacking position, the diaphragm 30 points toward the direction of the first stacking position toward the second stacking position ( Figures 6 to 8 During the folding process, the positioning member 70 and the diaphragm 30 are completely fitted together in the width direction of the diaphragm 30, and the positioning member 70 can support the diaphragm 30, so that the diaphragm 30 is completely positioned and constrained by the positioning member 70 in the width direction. Compared with the prior art in which the diaphragm is only positioned and constrained at the opposite ends in the width direction, the diaphragm 30 will not have problems such as wrinkles, collapse, and bulging when it is folded.

[0076] Step S5, see Fig. 9 , control the positioning member 70 to move to the second auxiliary position located on the side of the second pole piece 20 close to the roller group 40. Similarly, the positioning member 70 is attached to the surface of the diaphragm 30 facing away from the lamination table 50 from one side to the other side along the width direction of the diaphragm 30.

[0077] Step S6, see Fig.10 , the lamination platform 50 is switched from the second lamination position 20 to the first lamination position, and the positioning member 70 fixes and supports the diaphragm 30 relative to the lamination platform 50 when the lamination platform 50 is switched from the second lamination position to the first lamination position.

[0078] It is also understandable that when the stacking platform 50 is moved from the second stacking position to the first stacking position, the diaphragm 30 points in the direction of the second stacking position to the first stacking position ( Fig.10 During the folding process, the positioning member 70 and the diaphragm 30 are completely fitted together in the width direction of the diaphragm 30. Therefore, the positioning member 70 can also support the diaphragm 30, so that the diaphragm 30 is completely positioned and restrained by the positioning member 70 in the width direction. Therefore, when the diaphragm 30 is folded, wrinkles, collapses, bulges and other problems will not occur.

[0079] Step S7, please refer to Figures 11 to 13 Repeat the stacking steps of the first pole sheet 10 and the second pole sheet 20 (i.e., the aforementioned steps S2 to S6) until the required plurality of first pole sheets 10 and the plurality of second pole sheets 20 are alternately stacked, and each adjacent first pole sheet 10 and second pole sheet 20 are separated by the separator 30, to obtain a stacked battery cell 2 (see Figure 3 ).

[0080] When the stacked battery cell 2 is prepared according to the battery cell preparation method provided by the present invention and the battery cell preparation system 1 described in any of the above embodiments, the positioning member 70 can be utilized to fit the diaphragm 30 from one side to the other side in the width direction of the diaphragm 30, thereby supporting and completely positioning and restraining the diaphragm 30 during the stacking process, ensuring that the diaphragm 30 does not have wrinkles, collapses, bulging, and other problems when it is folded back and forth in a "Z" shape, which is beneficial to improving the quality of the manufactured stacked battery cell 2.

[0081] It should be noted that, in an embodiment of the present invention, when the stacking table 50 completes a stacking position switch and the first pole piece 10 or the second pole piece 20 is stacked on the diaphragm 30, that is, after the positioning member 70 supports and assists the diaphragm 30 to complete a folding and a new pole piece is stacked on the diaphragm 30, the positioning member 70 can be moved to the first auxiliary position or the second auxiliary position accordingly, so as to support and assist the diaphragm 30 to perform the next folding when the stacking table 50 switches the stacking position again, so as to realize the repetition of steps S2 to S6.

[0082] Alternatively, if Figure 8 and Fig.12As shown, in one embodiment of the present invention, the positioning member 70 is made of an electrothermal material (not limited to metal materials such as copper and iron), and the positioning mechanism also includes a power supply (not shown in the figure), and the power supply is used to supply power to the positioning member 70 to heat the positioning member 70. The battery cell preparation method also includes the step of: when the stacking station 50 completes the stacking position switching and the first pole piece 10 or the second pole piece 20 is stacked on the diaphragm 30, the positioning member 70 is also used to energize and generate heat to fuse the diaphragm 30. In this way, the positioning member 70 can be detached from the diaphragm 30 to facilitate movement to the corresponding first auxiliary position or the second auxiliary position. Preferably, in this embodiment, the positioning member 70 is provided with an anti-stick coating or an anti-stick layer composed of anti-stick elements such as an anti-stick sleeve (not shown in the figure) at least on the portion that is in contact with the diaphragm 30, so as to prevent slag from adhering to the positioning member 70 when the positioning member 70 melts the diaphragm 30, thereby ensuring that the surface of the positioning member 70 that is in contact with the diaphragm 30 is smooth, avoiding the occurrence of bulges on the portion where the diaphragm 30 and the positioning member 70 are in contact, and preventing the diaphragm 30 from being worn and broken by slag when being folded.

[0083] Of course, in other embodiments, the battery cell preparation system 1 may further include a cutter. The battery cell preparation method further includes the step of: when the stacking station 50 completes the stacking position switching and the first pole piece 10 or the second pole piece 20 is stacked on the diaphragm 30, the cutter is used to cut off the portion of the diaphragm 30 that is attached to the positioning member 70. In this way, the positioning member 70 can also be separated from the diaphragm 30 to facilitate moving to the corresponding first auxiliary position or the second auxiliary position, which will not be described in detail.

[0084] In an embodiment of the present invention, the diaphragm 30 used to separate the adjacent first pole piece 10 and the second pole piece 20 is melted or cut, so that the diaphragm 30 in the finally manufactured stacked battery cell 2 is a discontinuous multi-layer diaphragm. Compared with the stacked battery cell with a continuous diaphragm in the prior art, the stacked battery cell 2 in the present invention is not covered by the diaphragm 30 on both sides in the width direction of the pole pieces, so that the wetting effect in the electrolyte is better, which helps to improve the product quality of the battery in which the stacked battery cell 2 is located.

[0085] Furthermore, if Figure 5 and Figure 8 As shown, in one embodiment of the present invention, the battery cell preparation system 1 further includes a pressing claw mechanism 80, the pressing claw mechanism 80 includes a first pressing claw 81 and a second pressing claw 82, and the battery cell preparation method further includes the following steps: Figure 5 As shown, when the first pole piece 10 is stacked on the diaphragm 30, the first pressing claw 81 is controlled to press the first pole piece 10; and Figure 8As shown, when the second pole piece 20 is stacked on the diaphragm 30, the second pressing claw 82 is controlled to press the second pole piece 20. In this embodiment, when the lamination table 50 is laminating, the first pressing claw 81 and the second pressing claw 82 are respectively used to press the first pole piece 10 and the second pole piece 20 that are alternately stacked, which can not only ensure that any of the pole pieces is always in a compressed state during the lamination process to prevent the pole pieces from shifting, but also avoid cross-contamination of active materials on pole pieces of different polarities, which is helpful to improve the quality of the manufactured stacked battery cell 2.

[0086] It should be noted that the plurality of first pole pieces 10 and the plurality of second pole pieces 20 are alternately stacked in sequence, so the first pressing claw 81 and the second pressing claw 82 need to release the pressing effect on the pole piece in a timely manner after pressing a corresponding pole piece, so as to be used to press the corresponding next pole piece.

[0087] The cell preparation method further comprises the following steps: while or after the second pole piece 20 is stacked on the first pole piece 10 pressed by the first pressing claw 81 and the second pole piece 20 is pressed by the second pressing claw 82, the first pressing claw 81 is withdrawn from between the first pole piece 10 and the second pole piece 20, so as to prepare for pressing the other first pole piece 10 when another first pole piece 10 is stacked on the second pole piece 20; or, after the second pole piece 20 and another first pole piece 10 are stacked on the first pole piece 10 pressed by the first pressing claw 81, the first pressing claw 81 is withdrawn from between the first pole piece 10 and the second pole piece 20, so as to press the other first pole piece 10; a first pole piece 10; and, at the same time or after the first pole piece 10 is stacked on the second pole piece 20 pressed by the second pressing claw 82 and the first pole piece 10 is pressed by the first pressing claw 81, the second pressing claw 82 is withdrawn from between the second pole piece 20 and the first pole piece 10, so as to be ready to press the other second pole piece 20 when another second pole piece 20 is stacked on the first pole piece 10, or, after the first pole piece 10 and another second pole piece 20 are stacked on the second pole piece 20 pressed by the second pressing claw 82, the second pressing claw 82 is withdrawn from between the second pole piece 20 and the first pole piece 10, so as to be used to press the other second pole piece 20.

[0088] In the embodiment of the present invention, the first pressing claw 81 and the second pressing claw 82 have two different withdrawal modes respectively, and different matching schemes can be used to release the pressing effect on the corresponding pole piece in a timely manner, which has high flexibility in use.

[0089] It should also be noted that, in the embodiments of the present invention, any of the pressure claws preferably adopts a flat plate structure with a relatively thin thickness. When the diaphragm 30 is folded and stacked with any of the pole pieces, the diaphragm 30 covers the corresponding pressure claw together. The portion of the diaphragm 30 covering the pressure claw will produce a slight bulge. When the pressure claw is pulled out, the portion of the diaphragm 30 covering the pressure claw will collapse to a certain extent. As long as the thickness of the pressure claw is reasonably controlled, it can be ensured that the collapsed portion of the diaphragm 30 has little or no effect on the manufactured stacked battery cell 2.

[0090] It is understandable that the battery cell preparation method provided by the present invention can be used in the battery cell preparation system 1 described in any of the above embodiments, so in the process of preparing the stacked battery cell 2, all the beneficial effects brought by the battery cell preparation system 1 described in any of the above embodiments can also be achieved. For a more specific description of the battery cell preparation system 1, reference can be made to the relevant contents in the above embodiments, which will not be repeated here.

[0091] Furthermore, if Figure 3 As shown, the present invention further provides a stacked battery cell 2, which is manufactured by the above-mentioned battery cell manufacturing method, and thus has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated herein.

[0092] Furthermore, the present invention also provides a battery, which includes the above-mentioned stacked battery cell 2. The stacked battery cell 2 is manufactured by the above-mentioned battery cell preparation method, and therefore has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be elaborated on.

[0093] The battery may be a hard battery with a shell, and the stacked battery cell 2 is arranged in the shell. The battery may also be a soft-pack battery with a soft-pack film (not limited to aluminum-plastic film), and the stacked battery cell 2 is arranged in the soft-pack film. There is no limitation on this.

[0094] In the description of the present invention, the description with reference to the terms "embodiment", "specific embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0095] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery cell preparation system, characterized in that: include: Roller set for transporting the diaphragm; A stacking platform is arranged below the roller group, a portion of the diaphragm adjacent to one end thereof close to the stacking platform is laid on the stacking platform, the stacking platform and / or the roller group can be moved in a horizontal direction to switch the stacking platform between a first stacking position and a second stacking position, the first stacking position and the second stacking position are respectively located below opposite sides of the roller group in a horizontal direction, and the diaphragm can be folded when the stacking position of the stacking platform is switched; A transport mechanism, used for transporting a first pole piece to be stacked on the diaphragm above the stacking platform located at the first stacking position, and transporting a second pole piece to be stacked on the diaphragm above the stacking platform located at the second stacking position, wherein the first pole piece and the second pole piece have opposite polarities, are alternately stacked and separated by the diaphragm; A positioning mechanism, comprising a positioning member extending along the width direction of the diaphragm and movable and switchable between a first auxiliary position and a second auxiliary position; when the first pole piece is stacked on the diaphragm, the positioning member can be moved to the first auxiliary position located on a side of the first pole piece close to the roller group; when the second pole piece is stacked on the diaphragm, the positioning member can be moved to the second auxiliary position located on a side of the second pole piece close to the roller group; Among them, the positioning member is made of electrothermal material, and the positioning mechanism also includes a power supply, which is used to supply power to the positioning member to heat the positioning member; when the stacking platform completes the stacking position switching and the first pole piece or the second pole piece is stacked on the diaphragm, the positioning member is also used to be energized to generate heat to fuse the diaphragm; and when the positioning member is located at any of the auxiliary positions, it is attached to the surface of the diaphragm facing away from the stacking platform from one side of the diaphragm to the other side along the width direction, and the positioning member is used to be fixed relative to the stacking platform to support the diaphragm when the stacking platform switches the stacking position, and move to the first auxiliary position or the second auxiliary position when the stacking platform completes the stacking position switching and the first pole piece or the second pole piece is stacked on the diaphragm.

2. The battery cell preparation system according to claim 1, characterized in that: The positioning member is provided with an anti-sticking layer at least on the portion in contact with the diaphragm.

3. The battery cell preparation system according to any one of claims 1 or 2, characterized in that: The positioning mechanism further comprises a mounting frame and a driving member, wherein the mounting frame is used to mount the positioning member; The driving member is used to control the movement of the positioning member on the mounting frame, so that the positioning member is fixed relative to the stacking table when the stacking table switches the stacking position, and can move relative to the stacking table to the first auxiliary position or the second auxiliary position when the stacking table completes the stacking position switching and the first pole piece or the second pole piece is stacked on the diaphragm.

4. The battery cell preparation system according to claim 3, characterized in that: The mounting frame is fixed on the lamination table; When the stacking station switches the stacking position, the driving member is in a stopped state, and the mounting frame and the positioning member move synchronously with the stacking station relative to the roller group, so that the positioning member is fixed relative to the stacking station; when the stacking station completes the stacking position switching and the first pole piece or the second pole piece is stacked on the diaphragm, the driving member is in a working state, and the driving member drives the positioning member to move on the mounting frame, so that the positioning member can move to the first auxiliary position or the second auxiliary position relative to the stacking station.

5. The battery cell preparation system according to claim 3, characterized in that: The movement of the positioning member on the mounting frame driven by the driving member includes horizontal movement and vertical movement. The horizontal movement is used to move the positioning member from above one side of the stacking platform to above the other side in the horizontal direction, and the vertical movement is used to enable the positioning member to avoid collision during the horizontal movement.

6. The battery cell preparation system according to any one of claims 1 or 2, characterized in that: The cross-sectional shape of the positioning member perpendicular to its extension direction is one of oblate, circular or elliptical, and / or the battery cell preparation system further includes a cleaning mechanism, which is used to clean the positioning member.

7. The battery cell preparation system according to any one of claims 1 or 2, characterized in that: The device further comprises a pressing claw mechanism, wherein the pressing claw mechanism comprises a first pressing claw and a second pressing claw, wherein the first pressing claw is used to press the first pole piece when the first pole piece is stacked on the diaphragm, and the second pressing claw is used to press the second pole piece when the second pole piece is stacked on the diaphragm; Wherein, at the same time or after the second pole piece is stacked on the first pole piece pressed by the first pressing claw and the second pole piece is pressed by the second pressing claw, the first pressing claw is withdrawn from between the first pole piece and the second pole piece, so as to be prepared to press the other first pole piece when another first pole piece is stacked on the second pole piece, or, after the second pole piece and another first pole piece are stacked on the first pole piece pressed by the first pressing claw, the first pressing claw is withdrawn from between the first pole piece and the second pole piece, so as to be used to press the other first pole piece; At the same time or after the first pole piece is stacked on the second pole piece pressed by the second pressing claw and the first pole piece is pressed by the first pressing claw, the second pressing claw is withdrawn from between the second pole piece and the first pole piece to be used for pressing the other second pole piece when another second pole piece is stacked on the first pole piece, or, after the first pole piece and another second pole piece are stacked on the second pole piece pressed by the second pressing claw, the second pressing claw is withdrawn from between the second pole piece and the first pole piece to be used for pressing the other second pole piece.

8. A method for preparing a battery cell, used in the battery cell preparation system according to any one of claims 1 to 7, characterized in that: The battery core preparation method comprises: Providing a diaphragm and conveying it through a roller set, laying a portion of the diaphragm adjacent to one end thereof close to the lamination table on the lamination table; Placing the lamination table at a first lamination position below one side of the roller group in the horizontal direction, and conveying the first pole piece to the diaphragm stacked on the lamination table by a conveying mechanism, and then lifting the conveying mechanism; Controlling the positioning member to move to a first auxiliary position located on a side of the first pole piece close to the roller group, the positioning member being attached to a surface of the diaphragm facing away from the lamination table from one side to the other side along the width direction of the diaphragm; The stacking platform is switched from the first stacking position to the second stacking position located below the other side of the roller group in the horizontal direction, and the second pole piece is transported to the diaphragm stacked on the stacking platform by the transport mechanism, and then the transport mechanism is lifted, and the positioning member fixes and supports the diaphragm relative to the stacking platform when the stacking platform is switched from the first stacking position to the second stacking position; wherein the second pole piece has opposite polarity to the first pole piece; Control the positioning member to move to a second auxiliary position located on a side of the second pole piece close to the roller group, and the positioning member is attached to a surface of the diaphragm facing away from the lamination table from one side to the other side along the width direction of the diaphragm; The stacking platform is switched from the second stacking position to the first stacking position, and the positioning member fixes and supports the diaphragm relative to the stacking platform when the stacking platform is switched from the second stacking position to the first stacking position; Repeating the step of stacking the first pole piece and the second pole piece until a required plurality of the first pole pieces and a plurality of the second pole pieces are alternately stacked, and each adjacent first pole piece and second pole piece are separated by the diaphragm, so as to obtain a stacked battery cell; Wherein, the positioning member is made of an electrothermal material, and the positioning mechanism further includes a power supply, and the power supply is used to supply power to the positioning member to heat the positioning member; the battery cell preparation method further includes: When the lamination station completes the lamination position switching and the first pole piece or the second pole piece is stacked on the diaphragm, the positioning member is also used to be energized to generate heat to fuse the diaphragm.

9. The method for preparing a battery cell according to claim 8, characterized in that: The battery cell preparation system further includes a pressing claw mechanism, and the pressing claw mechanism includes a first pressing claw and a second pressing claw; The battery preparation method further comprises: When the first pole piece is stacked on the diaphragm, controlling the first pressing claw to press the first pole piece; When the second pole piece is stacked on the diaphragm, controlling the second pressing claw to press the second pole piece; At the same time or after the second pole piece is stacked on the first pole piece pressed by the first pressing claw and the second pole piece is pressed by the second pressing claw, the first pressing claw is withdrawn from between the first pole piece and the second pole piece, so as to be ready to press the other first pole piece when another first pole piece is stacked on the second pole piece, or after the second pole piece and another first pole piece are stacked on the first pole piece pressed by the first pressing claw, the first pressing claw is withdrawn from between the first pole piece and the second pole piece, so as to press the other first pole piece; and At the same time or after the first pole piece is stacked on the second pole piece pressed by the second pressing claw and the first pole piece is pressed by the first pressing claw, the second pressing claw is withdrawn from between the second pole piece and the first pole piece to be used for pressing the other second pole piece when another second pole piece is stacked on the first pole piece, or, after the first pole piece and another second pole piece are stacked on the second pole piece pressed by the second pressing claw, the second pressing claw is withdrawn from between the second pole piece and the first pole piece to be used for pressing the other second pole piece.

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