JP2003031264A - Thin plate folding method, its device and manufacturing method of lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin plate folding method and its device capable of correctly folding the thin plate at a predetermined position without giving damage to it and to provide a manufacturing method of a lithium ion secondary battery using the folding method for machining a sealed container. SOLUTION: The thin plate 1 held by a tool 15 on a base 11 is folded by movement of a roller-like pressing tool in the folding direction from the lower direction of the base 11. The tool 15 is separated and the thin plate 1 is clamped by clamp bar means 13a and 13b. The folded thin plate 1 is pressed by pressing means 21 and 22 from its upper side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin plate bending method and apparatus capable of accurately bending the thin plate at a predetermined position without damaging the thin plate, and a lithium ion using the bending method for processing a closed container. The present invention relates to a method for manufacturing a secondary battery.

[0002]

2. Description of the Related Art In order to meet the demand for energy saving of a sealed secondary battery which is a power source for electronic equipment such as a video camera and a headphone stereo, it absorbs and releases lithium such as lithium metal, lithium alloy or carbonaceous material. Development of non-aqueous electrolyte batteries that use substances that can be used as negative electrode materials has become active. Among them, it is possible to reduce the volume occupied by regions other than electrode bodies in the volume of sealed secondary batteries. Since it is advantageous for high energy and miniaturization of the sealed secondary battery, it is thin-walled instead of the metal can such as iron or aluminum that is conventionally used for the exterior material (sealed container) of the sealed secondary battery. A sealed secondary battery using a thin metal laminating material (hereinafter, referred to as a laminating material) that can be made into an exterior material is drawing attention.

The laminate material is composed of a soft metal film such as aluminum foil and a plastic film such as nylon, polyethylene or polypropylene. When used as an exterior material for a sealed secondary battery, it contains an electrode body. In this state, the corresponding surfaces of the exterior material are generally sealed by heat fusion.

In this case, the form of the laminated material is roughly classified into two types. One is a form in which a sheet-shaped laminated material is directly formed into a bag shape to accommodate the electrode body,
The other is a form in which a laminate material is drawn and the electrode body is housed in the drawn portion.

Comparing the two, the latter is formed by forming a squeeze-molded portion that matches the shape of the electrode body to be housed.
Compared with the former, there is an advantage that the ratio of the electrode body to the volume of the sealed secondary battery can be increased.

In the process of manufacturing a lithium-ion secondary battery, a laminate-shaped electrode body is housed in the laminate in a process of manufacturing a lithium ion secondary battery by a form in which the laminate material is subjected to draw molding and the electrode body is housed in the drawn-molded portion. After being stored in a pocket-shaped recess, the laminated material is folded in two and packaged, and then the laminated material is temporarily joined by spring back of the laminated material so that the folded-back dimension is not disturbed.

When this laminated material is bent, the laminated material is held in a state where there is no deformation, scratches or perforations caused by curling of the laminated material or bending at an unintended portion, and a reference bending line (such as a punch in the previous step). There is a case where it is pre-processed and a case where it is a virtual line in which nothing is done in the pre-processing.) It is necessary to perform the bending process along the creases so that the four sides accurately overlap each other.

[0008] Further, the electrode body to be packaged is not damaged by external damage, and the electrode body is prevented from popping out of the electrode body insertion pocket of the laminate material. It is necessary to process without any. In the case of folding into two in accordance with the dimensions during this bending process, a series of operations of each bending process were performed by pneumatic pressure, an electric actuator, or manually as an operation source of a bending jig or machine.

[0009] In a processing machine which has been conventionally used by combining air pressure and an electric actuator, a laminate material and an electrode body are placed at a predetermined position on a pedestal for holding a laminate material, and a bending reference plate is provided. Arranged and held the electrode body with the jig for holding the electrode body, and provided with various mechanisms and functions such as a folding jig, a crease construction jig, a holding chuck in a two-fold state, and a temporary joining jig. Equipment required. In addition, related cooperative operation by them is required.

[0010]

However, in the case of an apparatus in which a variety of mechanisms are combined as described above, the external shape of the apparatus becomes large and the operation as a whole is inevitably large. The laminate material and members such as the electrode body may be damaged, such as scratches, due to impact or the like. Further, when the respective members held on the pedestal are displaced in position, it is impossible to accurately fold the laminate material in two even if the respective mechanisms operate accurately.

Further, in order to prevent operation interference of each mechanism,
Since a small time lag is provided between the operations to perform the bending process, a timing at which the laminate material or the like is completely released (cannot be held) temporarily occurs. At this time, if the member moves even a little due to external force or internal reaction force of the white material,
When folded, the four sides do not overlap accurately. Further, when the step of processing the fold line is divided into several steps, there is a possibility that the operation with respect to the processing point between each step may shift. In this case also, as described above, the four sides cannot overlap with each other with high precision.

Further, when pneumatic actuators are used in combination, it is difficult or impossible to finely adjust the speeds of the actuators and cooperate with each other. Therefore, it is not possible to perform the bending process while the laminate material is always held. In addition, since it is difficult to perform a three-dimensional operation by simultaneous operation on two or more axes, it is not good at the operation of moving each member while avoiding each member when retracting each mechanism. If a part of the mechanism touches each member, it may cause damage.

Further, when the electric actuator is used, multi-axis simultaneous control for operating each mechanism is required, so that the control system becomes complicated and the entire mechanism becomes large and complicated. Therefore, at the time of processing, as in the case of processing with a pneumatic actuator, since the mechanism becomes large, it is difficult to bend the laminate material while always holding it. At the same time, the number of axes increases with the complexity of the mechanism, which increases the occupied space, makes control difficult, and impedes speeding up, making it difficult to use as a general-purpose machine.

Generally, when many actuators are used, irregular operation is considered. At this time, unless each member is positioned with a predetermined accuracy, as a result, the performance of the lithium ion secondary battery cannot be ensured, or
It cannot be handled as a product due to scratches.

Further, when the bending work is carried out by an operator, a manpower for ensuring a predetermined production speed and a working difference due to the manpower are generated, so that the production number of the lithium ion secondary battery is secured. However, it was a hindrance to securing and improving performance. If temporary joining is performed in a state where the folds are not aligned, the external dimensions are abnormal, making it impossible to produce products in the subsequent process. In addition, when the electrode body is temporarily joined at a position that is not normal, the movement distance with the equipment to be joined may change.
Damage to the device itself is also a concern.

In any case, when the laminate material is damaged due to the above-mentioned various causes, the damage of each member is not damaged, but the battery characteristics are inferior to that of the product, and the lithium ion secondary This will lead to reduced battery performance. Further, even if the defect does not immediately cause a defect, it becomes a product with a sufficient risk of becoming defective over time. Also, if the laminate material is not bent accurately, the external dimensions of the lithium ion secondary battery will be abnormal,
In this state, if the electrolyte is poured into the subsequent process and the electrolytic solution is injected, leakage or bleeding may occur and a defective product may be manufactured.

The present invention has been made in view of the above circumstances, and is applied to a thin plate bending method and apparatus for accurately bending a thin plate at a predetermined position without damaging the thin plate, and a closed container. It is an object of the present invention to provide a method for manufacturing a lithium ion secondary battery using the folding method.

[0018]

According to the present invention, a clamping step of clamping a thin plate at a predetermined position on the upper surface of a pedestal by a clamp means, and an arrow chord is arranged inside a bent position of the clamped thin plate, A holding step of releasing the clamp to hold the thin plate by the arrow string, a bending step of bending the thin plate held by the arrow string by moving a roller in a bending direction, and a step of bending the thin plate from the thin string. And a pressing step of pressing the thin plate with the clamping means, and pressing the thin plate from above the bent thin plate by the pressing means.

Further, according to the present invention, the predetermined position where the thin plate is clamped by the clamp means on the upper surface of the pedestal is:
This is a method of bending a thin plate, which can be set freely.

Further, according to the present invention, there is provided a method for bending a thin plate, characterized in that the thin plate is fixed to the pedestal by the clamping means or an arrow string through a working process.

Further, according to the present invention, the pedestal provided with a clamp means for holding the thin plate on the upper surface, the arrow string for closely fixing the thin plate clamped to the pedestal at a predetermined position, and the upper surface of the pedestal And a roller movable along the upper surface from the side wall of the pedestal, and a thin plate bending apparatus.

Further, according to the present invention, the pressing means is a bending device which comprises a stretcher and a push bar, and contacts the bent thin plate on the pedestal with a time lag.

Further, according to the present invention, there is provided a method for manufacturing a lithium ion secondary battery, characterized in that the above-mentioned thin plate bending method is used for bending the laminate material forming the closed container.

Further, according to the present invention, there is provided a method for manufacturing a lithium ion secondary battery, wherein the laminate material is bent while the electrode body is housed in the pocket portion.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First, as an example of a thin plate of a workpiece, the shape of a laminate material which is a part of a sealed container (exterior material) of a lithium ion secondary battery will be described. FIG. 1 is a perspective view of a laminated material before bending.

The laminating material 1 is a thin plate-like sheet formed by laminating plastic films such as nylon, polyethylene and polypropylene on both sides of a soft metal film such as aluminum foil. Further, a container-shaped pocket portion 3 for accommodating the electrode body 2 whose external perspective view is shown in FIG. 2 is formed. The electrode body 2 has a coiled electrode body 2a formed by laminating and winding several kinds of thin plates, a positive electrode tab 4a, and a negative electrode tab 4b extending to the outside. In the case of forming the lithium ion secondary battery, the corresponding surfaces of the closed container (not shown), which is an exterior material formed by bending the laminate material 1 in a state where the electrode body 2 is housed in the pocket portion 3, are heat-melted. It is sealed by wearing.

3 and 4 are exploded perspective views of essential parts of the thin plate bending apparatus of the present invention. FIG. 3 is an extracted view of a portion related to the first half of the processing step, and FIG. 4 is a processing step. It is the figure which extracted the part related to the latter half part of. Therefore, the thin plate bending apparatus as a whole has a configuration in which the portion shown in FIG. 3 and the portion shown in FIG. 4 are combined.

As shown in FIG. 3, a pedestal 11 on which a laminate 1 as a work is placed is provided with a step 12 having a concave portion at the center.
Are formed. The step portion 12 corresponds to the shape of the pocket portion 3 of the laminate material 1. Further, a pair of clamp bars 13a and 13b is provided at both ends of the pedestal 11 so as to rotate in the surface direction of the pedestal 11 and fix and hold both sides of the laminate material 1 placed on the pedestal 11. Further, above the pedestal 11, there is provided an arrow chord 15 which is movable up and down by a drive mechanism (not shown) with respect to the upper surface of the pedestal 11 and is movable rearward. The arrow chords 15 serve as a reference when the laminate material 1 is correctly folded back in half, and are arranged so that the knife edge portion 15a, which is the tip thereof, can be inserted so as to match the bending line of the folding portion of the laminate material 1. To be done. The arrow string 15 also functions as a holding jig for preventing the electrode body 2 from rising when the laminate material 1 is bent.

Similarly, above the pedestal 11, the pedestal 1
A pair of punches 16a and 16b are provided on the upper surface of the unit 1 so as to be vertically movable. The punches 16a and 16b are provided to apply pressure to the folds so that the folded laminate material 1 does not cause an error due to the repulsive force. The springs adjust the force pressing the punches 16a and 16b. 17 and an adjusting collar 18.

Further, as shown in FIG. 4, a stretcher 21 and a push bar 22 are arranged above the pedestal 11 so as to be movable up and down with respect to the upper surface of the pedestal 11. Both the stretcher 21 and the push bar 22 have a holding plate 23.
Adjustment collars 24, which are held by a and 23b and respectively adjust the pressing force, are urged by springs 25. The biasing force of the spring 25 has a buffering function of preventing damage (scratches, dents, etc.) to the laminate material 1 during pressing.

The push bar 22 includes punches 16a, 16
The laminate material 1 that has been temporarily folded back by b is bent to a perfect state, and the stretcher 21 is intended to remove wrinkles, slack, and looseness that occur when folded back. The timing of the operation of the push bar 22 and the operation of the stretcher 21 is set so that a time lag is provided in the operation time and the end of both operations falls within the state where the laminate material 1 is completely extended.

The pedestal 1 is provided below the pedestal 11 on the front side.
A guide block 26 is provided so as to be flush with the end face of the No. 1. Rollers 27a and 27b holding an elevating guide 32 are arranged at positions guided by the guide block 26. The rollers 27a and 27b are used to fold back the laminate material 1, and the torsion spring 2 for biasing
It is arranged so as to be held on the same plane as the folding reference plane. The rollers 27a and 27b are
Guide block 2 by a cam mechanism (not shown) during operation
Move up and down along 6.

The stretcher 21 and push bar 2
The second operation is performed by the rollers 27a, 27b and punches 16a, 1
6b, the laminated material 1
Is set to hold down.

Further, the stretcher 21 is made of the laminate material 1.
Before and after the time of contact with the clamp bars 13a, 13
Clamp bar release pin 29 to open b
a and 29b are set to operate. The operation of the clamp bar release pins 29a and 29b is such that the push bar 2 is moved downward in the primary direction so that the timing can be adjusted.
2. The cylinders 31a and 31b are attached to the same base plate (not shown) so that they can operate simultaneously with the stretcher 21, and the clamp bar release pins 29a and 29b are attached to the cylinders 31a and 31b for the secondary descent when opened. It is realized by doing.

It should be noted that each driving is configured so that it can be performed by a cam mechanism (not shown), and the laminating material 1 can be folded back in a state in which the electrode body 2 is wrapped by the operation of each mechanism. .

Next, the operation of the thin plate bending apparatus described above will be described with reference to the flow chart shown in FIG.

First, as shown in FIG. 3, with the clamp bars 13a and 13b provided on the base 11 open,
The pocket portion 3 of the laminating material 1 is aligned with the step portion 12 of the pedestal 11, and the laminating material 1 and the electrode body 2 are placed on the pedestal 11. At that time, the clamp bars 13a and 13b are attached to the pedestal 11.
Then, the laminate material 1 is clamped. The laminating material 1 is correctly positioned and placed in the pocket portion 3. (S1), (S2) After that, the electrode body 2 is inserted into the pocket portion 3.
(S3) Subsequently, the tip 15a (knife edge side) of the arrow chord 15 is positioned at the folded line portion of the laminate material 1 to be folded in two. At this time, in order to prevent the electrode body 2 from rising and to prevent the laminate material 1 and the electrode body 2 from being damaged, the electrode body 2 is operated so as to be moved down from just above the contact with the laminate material 1. (It gradually descends and skews until approaching) Also, the clamp bars 13a, 1
Open 3b. (S4) Next, as shown in the operation explanatory view of FIG. 6, the elevating guide portion 32 provided with the rollers 27a and 27b located below the pedestal 11 is raised along the guide block 26 and passed through the folding reference plane. , The rollers 27a, 27 as shown in FIG.
b pushes up the free side of the laminate material 1, and finally the rollers 27a and 27b are moved to a state of riding on the folded laminate material 1. (Position indicated by imaginary line) At this time, since each member is held and fixed by the arrow chords 15, it does not move except on the free side. (S
6) When the rollers 27a and 27b ride on the member and pull out the arrow chords 15 as a bending reference at the stopped position in the rearward horizontal direction, at the same time, the clamp bars 13a and 13b are tilted down again to move or "displace" the members. To prevent. (S7) The bent portions are pressed by the punches 16a and 16b. (S
8) In this state, since each member is held and fixed by the clamp bars 13a and 13b, the bending roller 27
a and 27b return to the retracted position. (S9) Next, in order to finish the bending completely, the push bar 22 and the mounting base plate of the stretcher 21 start to descend. (Although they are divided in FIG. 4 for the sake of expression, there is no problem even if they are installed at the same position. Further, when the respective mechanisms are dispersed, the pedestal 11 is moved by the transport mechanism so that the folding process can be continued.) . By descending, the push bar 22 and the stretcher 21 start processing at the same time,
Since the gap is provided in terms of height, first, the push bar 22 comes into contact with the laminate material 1, and the pushing force set by the spring and the adjusting collar 17 forms a complete bending habit. After a slight delay, the stretcher 21 contacts and presses the laminate material 1.
(S10) Almost at the same time when the stretcher 21 comes into contact with the laminate material 1, the cylinder operates to drive the clamp bars 13a and 13b release pins to operate the clamp bars 13a and 13b to release the laminate material 1. With this release,
It is possible to stretch the processed wrinkles, slack, looseness, etc. toward the end of the laminate material 1. Also in this case, since the push bar 22 and the stretcher 21 hold and fix the members by sandwiching the members, the bent members do not move or shift.

In the laminate material 1, with the wrinkles, slack, looseness, etc. completely eliminated, the cylinder 31 is reversely operated again to separate the clamp bar release pins 29a, 29b from the clamp bars 13a, 13b. (S11) As a result, the half-folded laminate material 1 is held by the clamp bars 13a and 13b. Then, the base plate to which the push bar 22 and the stretcher 21 are attached can be lifted and retracted from the laminate material 1. Finally, when this state is maintained and the product is sent to the subsequent process, it can be carried out by thermally bonding to a portion that does not affect the product by a heat source such as a heat pin, which is heated to a high temperature, called a heat tool.

As described above, since the members such as the laminating material 1 are not completely opened during the entire bending process, the laminating material 1 placed at the proper position should be folded back accurately. Can be done.

In the above case, the rollers 27a, 27b
Although two pieces are arranged at both ends of the pedestal 11, the number is not particularly limited, and spherical parts may be used for the shapes of the rollers 27a and 27b. Also, the push bar 22 and the stretcher 21 are not limited in number and shape,
It may be divided or circular parts may be used.

Further, although all the peripheral mechanisms are arranged for one pedestal 11, the pedestal 11 is fixed to a tray or the like and tact-fed, and each mechanism is divided and arranged so that the time is reduced. The number of products manufactured per unit can be increased. As a result, the tact time is determined by the number of subdivisions of the mechanism, so that the target tact can be easily set.

The components of each mechanism that come into contact with the laminate material 1 are made of resin that does not cause damage, or
Parts with a resin film formed on the surface of metal parts are used.

As described above, the semi-finished product of the laminated material 1 which has been correctly folded back falls within the specifications of the external dimensions and has no damage such as scratches or dents on its outer appearance, and is folded back by injection of an electrolytic solution in a subsequent process. It is possible to prevent defects caused by Furthermore, it is possible to prevent defects due to bending that occur over time, and as a result, it is possible to maintain and improve the performance and characteristics of the lithium ion secondary battery.

Further, since the folding mechanism of the above embodiment is completely driven by the cam mechanism, the operation is continued at the timing once set (adjusted), so that the control can be easily performed. Therefore, complicated control is not required unlike the mechanism formed by the electric actuator that has to drive multiple axes simultaneously.

In addition, since each mechanism does not use a cylinder whose operation may become unstable in its main part, it is possible to operate without having to consider the operation buffer of each mechanism or the time margin.

Even when the size of the laminated material 1 is changed, the center of the laminated material 1 can be aligned with the moving end of the bent arrow string 15 by changing the holding position of the laminated material 1 fixed on the pedestal 11. For example, it can be bent exactly at a desired position.

Further, an air pressure mechanism that changes on a daily basis (the driving speed changes due to pressure change), a mechanism that requires delicate speed adjustment, an electric actuator that requires a complicated control method, and a position based on multiple axes In addition, since no mechanism or the like that has to realize speed adjustment and downsizing of the mechanism is particularly used, it is possible to perform the double folding process accurately in a state in which the laminate material 1 is always wrapped together with the electrode body 2. .

When a lithium ion battery is manufactured using a sealed container having the electrode body built therein, which is manufactured by the above-described thin plate bending apparatus, after the electrolyte is stored in the sealed container, the lithium ion battery is inserted from the surface side of the sealed container. The heater fittings heat and pressurize the peripheral portions, which are the sealing points of the closed container, to form a closed structure. In particular, the sealed container processed by the thin plate bending method of the present invention can reduce processing defects due to dimensional abnormalities of the two-fold bending of the laminate material 1, thereby maintaining and improving the performance of the lithium ion secondary battery. It will be possible.

[0050]

According to the present invention, a thin plate can be bent accurately at a predetermined position without damaging it.

Further, a good lithium ion secondary battery can be manufactured by using the closed container processed by the bending method.

[Brief description of drawings]

FIG. 1 is a perspective view of a laminated material before bending.

FIG. 2 is an external perspective view of an electrode body.

FIG. 3 is an exploded perspective view of a main part of the thin plate bending apparatus of the present invention.

FIG. 4 is an exploded perspective view of a main part of the thin plate bending apparatus of the present invention.

FIG. 5 is a timing chart of the thin plate bending apparatus of the present invention.

FIG. 6 is an explanatory diagram of a bending operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laminated material, 2 ... Electrode body, 3 ... Pocket part, 11
... Pedestal, 12 ... Step, 13a, 13b ... Clamp bar,
15 ... Arrow string, 16 ... Punch, 21 ... Stretcher, 22
... push bar, 27a, 27b ... roller, 32 ... lifting guide section

Continued front page    F term (reference) 4E063 AA01 AA02 BC01 CA13 GA10                       JA06                 5H011 AA09 CC02 CC06 CC10 DD03                       DD06 DD26                 5H029 AJ14 BJ04 CJ03 CJ06 CJ28                       CJ30 DJ02 EJ01 EJ12 HJ12

Claims (7)

[Claims] 1. A clamping step of clamping a thin plate at a predetermined position on an upper surface of a pedestal by a clamp means, an arrow string is arranged inside a bent position of the clamped thin plate, and the clamp is opened to perform the above-mentioned operation by the arrow string. A holding step of holding the thin plate, a bending step of bending the thin plate held by the arrow string by moving a roller in a bending direction, and a step of separating the arrow string from the thin plate to clamp the thin plate by the clamping means. A method of bending a thin plate, comprising: a pressing step of pressing the thin plate that has been clamped and bent from above by a pressing means. 2. The method for bending a thin plate according to claim 1, wherein a predetermined position where the thin plate is clamped by the clamp means on the upper surface of the pedestal can be set freely. 3. The method of bending a thin plate according to claim 1, wherein the thin plate is fixed to the pedestal by the clamp means or an arrow string through a working process. 4. A pedestal having clamp means for holding a thin plate on an upper surface thereof, an arrow string closely fixed to a predetermined position of the thin plate clamped on the pedestal, and movable up and down with respect to an upper surface of the pedestal. And a roller movable along the upper surface from the side wall of the pedestal. 5. The bending apparatus according to claim 4, wherein the pressing means is composed of a stretcher and a push bar, and contacts the bent thin plate on the pedestal with a time lag. 6. A method of manufacturing a lithium ion secondary battery, wherein the thin plate bending method according to claim 1 is used for bending a laminate material forming an airtight container. 7. The method for manufacturing a lithium ion secondary battery according to claim 6, wherein the laminate material is bent while the electrode body is housed in the pocket portion.