JP5157547B2 - Method and apparatus for manufacturing flat spiral electrode - Google Patents

Description

  The present invention relates to a secondary battery obtained by laminating and winding a separator between a positive electrode sheet and a negative electrode sheet, flattening the wound body and storing and enclosing it in a battery case together with an electrolytic solution. The present invention relates to a method and apparatus for manufacturing a flat spiral electrode that presses a body flat without wrinkles.

  The secondary battery is configured in a sealed manner having a positive electrode terminal and a negative electrode terminal in a rectangular parallelepiped battery case. The battery case is a rectangular container in which a metal plate forms a rectangular parallelepiped housing space, and a flat wound body (flat wound body) is inserted therein. In the flat wound body, a sheet-like positive electrode, a negative electrode, and a separator are wound into a cylindrical shape, and are pressed to form a flat shape. FIG. 10 is a diagram showing a method of manufacturing a flat spiral electrode disclosed in Patent Document 1 below.

A pair of separation rods 101, 101 are inserted from the inside of the wound body W wound in a cylindrical shape, and the separation rods 101, 101 move in the left-and-right direction away from each other so that they are spread and collapsed vertically Deform. Further, the wound body W is pressed into a flat shape by the upper press plate 111 and the lower press plate 112 of the press means 110 from the vertical direction.
In the wound body W, the electrode leads are then appropriately processed and stored in a battery case made of stainless steel, the internal electrode and the external electrode are connected, and the electrolytic solution is sealed and sealed. To produce a secondary battery.
JP 2000-173646 A JP-A-11-354380

  However, in the conventional method for manufacturing a flat spiral electrode and an apparatus therefor, wrinkles are generated on the flat wound body during press molding. When wrinkles occur in the flat wound body, the spacing between the positive electrode and the negative electrode and the separator sandwiched between them becomes non-uniform, and the active material of the positive electrode and the negative electrode peels off from the bent portion, and the bent portion The conductive material of aluminum foil or copper foil is broken and becomes a burr. As a result, the battery performance is adversely affected by increased resistance, decreased capacity, and self-discharge due to slight short circuit. Therefore, in order to secure stable battery performance, it is desired not to generate wrinkles when forming a pressure for forming a flat spiral electrode.

  Therefore, an object of the present invention is to provide a flat spiral electrode manufacturing method and a manufacturing apparatus for flattening a wound body without generating wrinkles, in order to solve such problems.

An apparatus for producing a flat spiral electrode according to the present invention is a flat electrode formed by placing a spirally wound spiral electrode temporarily formed into a figure of 8 sideways and crushing it with an upper and lower press head, The upper press head and the lower press head are located on the pressing surface side of the load receiving member that crushes the 8-shaped wound body into a flat shape, and the 8-shaped wound body And a leaf spring that elastically deforms into a flat plate state when the wound body is crushed by the load receiving member from a curved state hit along the curved surface portion.
Further, the flat spiral electrode manufacturing apparatus according to the present invention has a movable member biased by an elastic member in a direction in which a load is applied to the wound body, and the movable member protrudes from the pressing surface. It is preferable to be joined to the leaf spring in a curved state at a position.

In the flat spiral electrode manufacturing apparatus according to the present invention, it is preferable that the movable member is disposed at a central portion of the load receiving member and the movement is guided by the guide member.
In the flat spiral electrode manufacturing apparatus according to the present invention, the load receiving member and the leaf spring may be provided with a gap or a cut into which a gripping member that grips and conveys the temporarily formed 8-shaped wound body enters. It is preferable that a notch is formed.
In the flat spiral electrode manufacturing apparatus according to the present invention, it is preferable that a bearing is provided on the load receiving member side at a position where the leaf spring is rubbed.

  And the manufacturing method of the flat spiral electrode which concerns on this invention puts the winding body of the spiral electrode temporarily shape | molded in the figure 8 sideways, and makes it flat by crushing with an up-down press head, A curved leaf spring is applied to the curved portion recessed in each of the upper and lower directions with respect to the 8-shaped winding body, and the winding body is crushed together with the leaf spring to bring the leaf spring into a flat plate state. And the said winding body is made into a flat shape, It is characterized by the above-mentioned.

  Therefore, according to the present invention, in the process in which the 8-shaped wound body is crushed by the upper and lower press heads, a constant contact state with the leaf spring is always maintained, and the contact surfaces of both of them are almost the same without slipping. Therefore, it is possible to manufacture a flat spiral electrode without wrinkles.

Next, an embodiment of a method and apparatus for producing a flat spiral electrode according to the present invention will be described below with reference to the drawings.
In describing the manufacturing method of the flat spiral electrode according to the present embodiment, the problems caused by the conventional manufacturing method will be further examined. FIG. 6 is a conceptual diagram showing the cause of wrinkles when manufacturing a flat spiral electrode. A cylindrical wound body W as shown in FIG. 6 (a) is subjected to a temporary press in the previous step and is shaped into a figure 8 as shown in FIG. 6 (b).

Here, FIG. 7 is a conceptual diagram showing a temporary press device, and FIG. 8 is a perspective view showing a press head of the temporary press device. FIG. 9 is a view showing a conveying means for conveying the spiral electrode after temporary pressing.
The temporary press device 50 is provided with a pair of upper and lower temporary press heads 51, 51 and a pair of left and right extraction chucks 52, 52. The temporary press head 51 is pressed by a spring 54 at the center of a base 53. A block 55 is projected and a notch 56 is formed so as to sandwich the presser block 55.

  The wound body W is sandwiched between the upper and lower temporary press heads 51 and 51 of the temporary press device 50 by sandwiching the left and right portions at both ends in the axial direction by the chuck claws 52 a and 52 b of the punch chuck 52. Therefore, the distance between the upper and lower temporary press heads 51 and 51 is reduced, and the central portion of the wound body W is pressed by the presser blocks 55 and 55. As shown in FIG. 4, the wound body W is crushed up and down and deformed into a figure-eight shape. At that time, the wound body W is pulled left and right by the punching chucks 52 and 52. Then, when the central portion overlaps to form an 8-shaped wound body (hereinafter referred to as “8-shaped wound body”) Wa, the temporary pressing is finished, and the punching chuck 52 is removed. However, the wound body W is still sandwiched between the temporary press heads 51, 51.

  Next, as shown in FIG. 9, the figure-shaped wound body Wa is held at both ends in the axial direction by the conveyance chucks 57, 57. The chucks 57a and 57b of the transport chuck 57 enter the notch 56 of the temporary press head 51, and grip the central portion of the 8-shaped winding body Wa there. Thereafter, the temporary press heads 51 and 51 are separated from each other, and the released 8-shaped wound body Wa is conveyed to the next main press while being held by the conveyance chucks 57 and 57.

  Therefore, the figure-wrapping body Wa is placed on the lower press head 202 so that the figure- 8 is oriented sideways as shown in FIG. 6 (b), and is lowered as shown in FIG. 6 (c). The upper press head 201 is crushed with the lower press head 202. Thus, a flat spiral electrode having a flat shape is formed from the cylindrical wound body W.

  By the way, the figure-shaped winding body Wa at the time of pressing contacts the upper and lower press heads 201 and 202 at a part (contact portion P) and is crushed so that force is applied to the contact portion P from above and below. At that time, the contact portion P is not crushed straight in the up-and-down direction, and the center portion O side is bent, so that it moves to the left and right as shown by the arrow s in the process of becoming flat. However, if the contact portion P between the wound body and the upper and lower press heads 201 and 202 is slippery due to friction, the material such as the wound electrode and separator constituting the wound body has a force in the direction opposite to the arrow s. Will act.

  Then, in the figure wound body Wa, there is no escape space for the force acting from both the left and right toward the central portion O. As a result, the material of the central portion O is pushed and deformed from both the left and right sides. Become. Further, a deviation occurs between the stacked positive electrode sheet and negative electrode sheet. As mentioned above, although the cause of the occurrence of wrinkles has been verified, the manufacturing method and the manufacturing apparatus of the present embodiment are designed to eliminate the generation of wrinkles by paying attention to the action of such force. FIG. 1 is a conceptual diagram showing a method and apparatus for manufacturing such a flat spiral electrode.

  The manufacturing method of this embodiment presses the temporarily pressed 8-shaped wound body Wa, and crushes it into a flat shape, similarly to the conventional method described above. In that case, the press apparatus 10 which is a manufacturing apparatus is provided with leaf springs 15 and 15 which come into contact with the upper and lower curved surfaces k of the figure-shaped wound body Wa. Accordingly, at the time of pressing, as shown in FIG. 1A, the figure-shaped wound body Wa is sandwiched so as to be supported by the upper and lower leaf springs 15 and 15. Therefore, the figure-shaped wound body Wa is always in contact with the leaf springs 15 and 15 while being deformed into a flat shape as shown in FIG.

  Therefore, the press device 10 is provided with leaf springs 15 for the upper press head 11 and the lower press head 12, respectively. The leaf spring 15 is a plate that is curved with a predetermined curvature in accordance with the curved surface k of the figure-shaped wound body Wa, and the top T thereof is located at the center of each of the upper and lower press heads 11 and 12. The upper and lower press heads 11 and 12 are provided with a movable member 16 movable in the vertical direction at the center thereof, and a leaf spring 15 is joined to the tip thereof. Although details will be described later, the movable member 16 is urged in the vertical direction so that the leaf spring 15 has a curved shape as illustrated.

  Therefore, after the figure-shaped wound body Wa is installed in the press device 10, the upper press head 11 gradually descends and is crushed with the lower press head 12. At that time, since the curved leaf spring 15 is free at the left and right end portions, the central portion thereof approaches the upper and lower press heads 11 and 12 and becomes flat by receiving a reaction force. The movable member 16 supporting the leaf spring 15 moves so as to be pushed into the upper and lower press heads 11 and 12 in response to the reaction force from the figure-shaped wound body Wa.

  In the process of being crushed by the upper and lower press heads 11, 12, the figure-shaped wound body Wa is always kept in constant contact with the leaf spring 15. That is, as the figure-shaped wound body Wa becomes flat, the curved leaf spring 15 becomes flat, and the contact surface between the figure-shaped wound body Wa and the leaf spring 15 almost slips. It is transformed in the same way. Therefore, according to the present embodiment, since the entire surface (curved surface k) of the 8-shaped wound body Wa pressed by the upper and lower press heads 11 and 12 is in contact with the leaf spring 15, the contact portion P is formed during press molding. The force does not act toward the central portion O without slipping (see FIG. 6C), and a flat spiral electrode without wrinkles can be formed.

  Next, a manufacturing apparatus for executing such a method of manufacturing a flat spiral electrode will be specifically described. FIG. 2 is a plan view showing the press head above or below the manufacturing apparatus. 3 and 4 are views showing a cross section AA of the press head shown in FIG. 2, FIG. 3 shows a non-pressed state, and FIG. 4 shows a pressed state. Since the press heads 20 arranged on the upper and lower sides constituting the manufacturing apparatus have the same configuration, only the lower side is shown in the drawing.

  The press head 20 has a pair of load receiving blocks 22 and 22 superimposed on the left and right in the longitudinal direction on a base 21 having a rectangular planar shape. The load receiving block 22 has an attachment portion 22a parallel to the base 21 and an upright portion 22b for receiving a load during pressing. The pair of load receiving blocks 22 and 22 fixed to the base 21 are arranged at a predetermined interval, and the center portion of the upright portion 22b has a notch cut out in a U-shape as shown in FIG. A portion 221 is formed.

  As in the case shown in FIG. 1, the press head 20 is disposed with the temporarily pressed figure 8 wound body Wa lying sideways, and the left and right cylindrical portions of the figure 8 are arranged on the left and right standing parts 22 b. It has become so. That is, as can be seen from FIG. 1 (c), in order to make the figure-shaped wound body Wa flat, it is necessary to apply a load mainly for creasing the left and right ends. 22 is comprised so that the said edge part may be pinched | interposed by the standing part 22b.

  On the other hand, the 8-shaped wound body Wa formed by the temporary press is gripped by the conveying chuck 57 as shown in FIG. 9 at both ends of the central portion O and fed into the manufacturing apparatus. Therefore, a space 30 is formed between the load receiving blocks 22 and 22 so that the chuck claws 57a and 57b do not hit. In addition, a movable block 26 that supports the leaf spring 25 is disposed in a wide space of the notch portion 221 formed between the load receiving blocks 22 and 22.

  The leaf spring 25 has a rectangular shape that covers the upright portions 22b and 22b of the left and right load receiving blocks 22 and 22, as shown by a two-dot chain line in FIG. 2, and avoids the chuck claws 57a and 57b according to the space 30. A U-shaped notch is formed. And it curves as shown in FIG. 3, and is formed with the predetermined | prescribed curvature. The movable block 26 that supports the leaf spring 25 is formed with a protrusion 26a at the center and is welded from the inside of the curved leaf spring 25. The movable block 26 is urged in the protruding direction (upward in the drawing) of the protrusion 26a so that the curved shape of the leaf spring 25 is maintained. Therefore, the movable block 26 is provided with an urging means and a guide means between the base 21.

  In the movable block 26, a circular hole 26b is formed in the center opposite to the protrusion 26a, and a coil spring 27 is loaded therein, and is pushed up by the elastic force received by the reaction force of the base 21 upward in the drawing. ing. On the other hand, the load receiving block 22 is formed with an overhanging portion 22c so as to limit the movement of the urged movable block 26, and as shown in FIG. 3, the movable block 26 is connected to the overhanging portion 22c. The hit position is the normal state of the press head 20. The leaf spring 25 in this state is a curved surface along the curved surface k of the figure-shaped wound body Wa.

  In addition, a slide mechanism is provided at two locations across the coil spring 27. The two slide mechanisms are composed of a shaft 28 fixed to the base 21 and a ball bush 29 attached to the movable block 26. The shaft 28 is fixed to the base 21 with a bolt and protrudes vertically. On the other hand, the ball bush 29 is loaded in the movable block 26 and fixed by bolts. Therefore, the movable block 26 in which the coil spring 27 is put is set on the base 21 so that the ball bush 29 is fitted to the upright shaft 28. Thereafter, as described above, the load receiving block 22 is fixed to the base 21 and the press head 20 is assembled.

  Accordingly, the temporarily pressed 8-shaped wound body Wa is held by the chuck and disposed on the lower press head 20. On the other hand, when the upper press head 20 is lowered, the state as shown in FIG. 1A is obtained, and the figure-shaped wound body Wa is sandwiched between the upper and lower leaf springs 25. Thus, at a predetermined timing when the figure wound body Wa is positioned, the conveyance chuck 57 is retracted, and the upper press head 20 is lowered to execute the press. As the distance between the upper and lower press heads 20, 20 decreases, the moving block 26 receives a reaction force, and the coil spring 27 contracts toward the base 21.

  Since the left and right end portions of the leaf spring 25 are in contact with the load receiving block 22, the center portion approaches the height of the end portion by the movement of the movable block 26 and gradually becomes flat. With the deformation of the leaf spring 25, the figure-shaped winding body Wa is also crushed, and the leaf spring 25 overlaps the top of the upright portion 22b of the load receiving block 22. And it becomes a flat spiral electrode so that a crease may be given to end part t of a winding object by applying predetermined load further. Therefore, as in the case shown in FIG. 1, the press device using this press head 20 is deformed in the same way with almost no sliding between the figure-shaped wound body Wa and the leaf spring 25 during the crushing process. Wrinkle generation can be prevented.

  Next, FIG. 5 is the figure which showed the modification about the manufacturing apparatus of a flat spiral electrode. This device is also a press device 30 provided with plate springs 35 on the upper and lower press heads 31 and 32. The leaf spring 35 is joined to the movable block 36, and the 8-shaped wound body Wa is sandwiched between the load receiving blocks 33 and 33 and is crushed during pressing. At that time, in the embodiment, as shown in FIG. 3, the end portion of the leaf spring 25 hits the corner portion of the load receiving block 22 and is rubbed. Then, the metal powder generated at the time of the press working may adhere to the flat spiral electrode, and may adversely affect the subsequent processes. Therefore, in the present embodiment, the bearing 37 is attached to the corner portion of the load receiving block 32 so that the leaf spring 35 is not rubbed.

As mentioned above, although embodiment was described about the manufacturing method and manufacturing apparatus of the flat spiral electrode which concern on this invention, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.
In the above-described embodiment, for example, the movable block 26 is joined to the central portion of the curved leaf spring 25 and the predetermined deformation of the leaf spring 25 is supported, but instead of the movable block 26, the end of the leaf spring 25 is slid. Any structure that can be deformed in both a curved state and a flat state may be used.
In the embodiment shown in FIG. 5, the bearing 37 is disposed at a position where the leaf spring 35 is rubbed. However, the shape of the position may be a curved surface.

It is the conceptual diagram which showed embodiment of the manufacturing method and manufacturing apparatus of a flat spiral electrode. It is the top view which showed the upper or lower press head of the manufacturing apparatus. It is the figure of the non-pressing state which showed the AA cross section of the press head shown in FIG. It is the figure of the press state which showed the AA cross section of the press head shown in FIG. It is sectional drawing which showed the press head equipped with the bearing. It is the conceptual diagram which showed the cause of the wrinkle which generate | occur | produces when manufacturing a flat spiral electrode from an 8-shaped winding body. It is the conceptual diagram which showed the temporary press apparatus. It is the perspective view which showed the press head of the temporary press apparatus. It is the figure which showed the conveyance means after temporary press. It is the figure which showed the manufacturing method of the flat spiral electrode shown by the following patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Press apparatus 11, 12 Press head 15 Leaf spring 16 Movable member 20 Press head 21 Base 22 Load receiving block 25 Leaf spring 26 Movable block 27 Coil spring 28 Shaft 29 Ball bushing Wa 8 character winding body

Claims (6)

In the manufacturing apparatus of the flat spiral electrode which makes the flat shape by placing the wound body of the spiral electrode temporarily formed into a figure of 8 sideways and crushing with the upper and lower press heads,
The upper press head and the lower press head are positioned on a load receiving member that crushes the 8-shaped winding body into a flat shape, and on the pressing surface side of the load receiving member, and the 8-shaped winding body. A flat spiral electrode having a leaf spring that elastically deforms into a flat plate state when the wound body is crushed by the load receiving member from a curved state hitting along a curved surface portion of the body Manufacturing equipment. In the flat spiral electrode manufacturing apparatus according to claim 1,
A movable member biased by an elastic member in a direction in which a load is applied to the wound body, the movable member being joined to the curved leaf spring at a position protruding from the pressing surface; An apparatus for producing a flat spiral electrode, In the flat spiral electrode manufacturing apparatus according to claim 2,
2. The flat spiral electrode manufacturing apparatus according to claim 1, wherein the movable member is disposed at a central portion of the load receiving member and guided to move by a guide member. In the flat spiral electrode manufacturing apparatus according to claim 2 or 3,
The load receiving member and the leaf spring are formed with a gap or a notch into which a gripping member that grips and conveys the temporarily formed 8-shaped wound body is inserted. Spiral electrode manufacturing equipment. In the flat spiral electrode manufacturing apparatus according to any one of claims 1 to 4,
2. A flat spiral electrode manufacturing apparatus according to claim 1, wherein a bearing is provided at a position where the leaf spring is rubbed on the load receiving member side. In the method for producing a flat spiral electrode, a spirally wound electrode electrode temporarily formed into a figure 8 is placed sideways and flattened by being crushed by upper and lower press heads.
A curved leaf spring is applied to the curved portions recessed in the upper and lower directions with respect to the 8-shaped winding body, and the winding body is crushed together with the leaf spring to bring the leaf spring into a flat state. A method of manufacturing a flat spiral electrode, wherein the wound body is formed into a flat shape.

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