JP2000173600A - Cutting device for sheet electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode cutting device capable of cutting a sheet electrode into the specified dimensions on the mass-productive basis without impairing the quality by introducing multi-speed automatic operation of a cutting mechanism in compliance with the buffer amount of the electrode fed running at a constant speed. SOLUTION: A cutting device for sheet electrodes comprises a pair of rotary pressure rollers 1a and 1b rotating at a constant speed and putting each electrode 2 in pressure attachment by the peripheral surface, a buffer amount sensing part 3 to sense the buffer amount of the electrode 2 having passed the rollers, a cutting mechanism 4 to cut the electrode 2 having passed the sensing part 3 into the specified lengths, and a drive mechanism 5 to operate the cutting mechanism 4, wherein the buffer amount sensing part 3 is equipped with a plurality of sensors A, B, C, D to make sensing in compliance with the change in the buffer amount by reference to a certain buffer amount and a control mechanism 6 to put the cutting mechanism 4 in multi-speed operation through control of the driving mechanism 5 in conformity to the sensing signals from the sensors A, B, C, D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet electrode cutting apparatus, and more particularly, to a sheet electrode cutting apparatus which cuts a sheet electrode in accordance with a supply / running speed of the sheet electrode.

[0002]

2. Description of the Related Art In recent years, with the promotion of cordless, high-performance, and compact and lightweight electronic devices such as portable telephones and portable notebook personal computers (PCs), the main power supply of these electronic devices has been increased. There is a demand for higher performance batteries. As a main power source for these electronic devices, nickel-metal hydride secondary batteries or lithium secondary batteries capable of achieving higher performance and higher capacity have been put into practical use.

By the way, this type of nickel-hydrogen secondary battery is generally wound or laminated with a separator carrying an electrolytic solution (electrolyte) interposed between a strip-shaped positive electrode and a strip-shaped negative electrode. A group (power generation element portion) is formed, and this electrode group is liquid-tightly sealed in a battery outer container. Here, an electrode group (electrode element portion) of a secondary battery, for example, an electrode group of a nickel-metal hydride secondary battery, generally has a positive electrode active material layer containing a nickel compound provided on a belt-shaped current collector. A negative electrode is formed by providing a negative electrode active material layer containing a hydrogen storage alloy having a CaCu ₅ type crystal structure on a belt-like current collector.

[0004] The above-mentioned band-shaped (sheet-shaped) electrode is prepared by preparing an electrode active material corresponding to the band-shaped current collector into a paste or gel, and coating the paste or gel electrode active material on the current collector surface. After processing, drying, and further performing a process such as pressure bonding, it is cut into a desired size. Here, the application of the electrode active material to the belt-like current collector surface increases the filling amount (the amount of the electrode active material carried) of the electrode active material in order to increase the capacity or improve the volume efficiency, and furthermore, In addition, after drying a coating film of an electrode active material-based paste, the pressure is applied to improve the adhesion density of the active material layer, and the capacity or performance of the electrode layer is increased.

[0005] Examples of the band-shaped current collector include a band-shaped metal foil such as aluminum, copper, nickel, titanium, and stainless steel, and a band-shaped wire mesh such as an ex-band metal or a band-shaped porous thin plate. The form of these band-shaped current collectors is a non-porous sheet, a perforated sheet, a net-like (net-like) sheet, and the like, and the thickness thereof is about 20 to 50 μm.

The cutting of the band-shaped (sheet-shaped) electrode is usually performed as follows. That is, after passing between the outer peripheral surfaces of a pair of rotary pressure rollers, and after pressing the sheet-shaped electrode, it is supplied and run to the electrode cutting mechanism via a buffer area or a feeder area, and cut into predetermined dimensions. I have. Here, the interposition of the buffer area and the feeder area causes a certain amount of slack between the rotary pressure roller and the electrode cutting mechanism, and excessive tension or the like is applied to the sheet-shaped electrode to be cut, which may cause damage. This is to avoid.

More specifically, while the rotary pressure roller and the electrode cutting mechanism are operated at a constant speed, a buffer amount detector for detecting the upper and lower limits of the buffer amount is arranged in the buffer area. The constant speed operation of the rotary pressure roller and the electrode cutting mechanism is controlled accordingly. With this configuration, when the buffer amount detector detects the buffer amount upper limit, the operation of the electrode cutting mechanism is temporarily stopped until the buffer amount returns to the reference amount side, and conversely, when the buffer amount lower limit is detected. Stops the operation of the rotary pressure roller temporarily until the buffer amount returns to the reference amount side. In other words, a method is employed in which the operation of the electrode cutting mechanism and the rotation-type pressure roller are controlled to be operated, temporarily stopped, and stopped, depending on the degree of slack in the buffer region of the sheet electrode to be supplied and run.

[0008]

In the case of a conventional sheet-shaped electrode cutting device, the rotary pressure roller and the electrode cutting mechanism are configured to operate and operate at a constant speed independently. In some cases, a change (difference) occurs in the calculated constant speed operation / operation speed for some reason, and the buffer amount (slack amount) in the buffer region frequently changes. Then, for each detection of the upper limit and the lower limit of the buffer amount, performing the operation of operating, temporarily stopping, and releasing the stop of the electrode cutting mechanism and the rotary pressure roller complicates the cutting operation of the sheet-shaped electrode, Productivity is also impaired. In particular, in the case where the operation of the rotary pressure roller is temporarily stopped, there is a problem that the quality of the sheet-like electrode in the pressing (rolling) process is easily affected, and the quality of the electrode is concerned.

The present invention has been made in view of the above circumstances, and automatically operates the electrode cutting mechanism at multiple speeds in accordance with the buffer amount of a sheet-like electrode that is supplied and run at a constant speed.
It is an object of the present invention to provide an electrode cutting apparatus capable of cutting sheet-shaped electrodes into a predetermined size in mass production without deteriorating quality.

[0010]

According to a first aspect of the present invention, there is provided a pair of rotary type pressure rollers for rotating at a constant speed and pressing a sheet-shaped electrode on an outer peripheral surface thereof, and a sheet-shaped roller passing through the rotary type pressure roller. A buffer amount detection unit that detects the buffer amount of the electrode, an electrode cutting mechanism that cuts the sheet-shaped electrode that has passed through the buffer amount detection unit to a predetermined length, and a driving mechanism that drives and operates the electrode cutting mechanism. A device for cutting a sheet-shaped electrode, comprising: a plurality of buffer amount detectors each of which detects a buffer amount corresponding to a change in buffer amount based on a fixed buffer amount, and the buffer amount detector. And a control mechanism for controlling the driving mechanism in response to the detection signal to operate the electrode cutting mechanism at multiple speeds.

According to a second aspect of the present invention, in the sheet electrode cutting apparatus according to the first aspect, a plurality of buffer amount detectors are arranged with a step along the traveling direction of the sheet electrode. I do.

In the first and second aspects of the present invention,
The pair of rotary pressure rollers are made of, for example, stainless steel, and pass between the pair of rotary pressure rollers (press rollers) after the electrode mixture applied (coated) on the belt-shaped current collector surface is dried. About 2 to 5 ton / cm at linear pressure, preferably at linear pressure.
Crimping is performed at about 3 to 4 ton / cm. The rotary pressure roller has a built-in heating source, if necessary, and is configured to be able to perform pressure bonding while the temperature of the rotary pressure roller is heated to about room temperature to about 200 ° C. In addition, the rotary drive source rotates at a constant speed within a range of an outer peripheral surface speed of about 10 m / min.

In the first and second aspects of the present invention,
The electrode cutting mechanism cuts a sheet-shaped electrode to be supplied and travels to a desired length and size, and includes a mechanism for intermittently moving a cutting blade forward and backward. The intermittent advance / retreat of the cutting blade is performed by the drive mechanism while being controlled in accordance with the buffer amount (the amount of looseness or the degree of looseness) of the sheet-like electrode to be supplied / run.

As a premise, a buffer amount detection unit provided between the rotary pressure roller and the electrode cutting mechanism firstly sets a reference buffer amount of the sheet-like electrode supplied from the rotary pressure roller, an upper limit, For example, the lower buffer amount
Detect changes in buffer volume. Here, the change in the buffer amount is detected by a buffer amount detector arranged at regular intervals in a direction perpendicular to the main surface of the sheet-like electrode, for example, along the supply / running direction of the sheet-like electrode.

For example, a plurality of detectors each including a light-emitting element and a light-receiving element arranged opposite to and separated from each other are supplied and supplied.
The electrodes are arranged at regular intervals in a direction substantially perpendicular to the main surface of the traveling sheet electrode. With such an arrangement, the buffer amount detector responds to either light blocking or light transmission depending on the buffer amount (slack amount) of the sheet-like electrode. Is output to a control mechanism for controlling the drive mechanism of the electrode cutting mechanism, and the electrode cutting mechanism is operated at multi-stage speed.

The cutting apparatus according to the first and second aspects of the present invention is a cutting apparatus in which an electrode mixture containing a positive electrode active material is applied and dried on the surface of a belt-like current collector (for example, a Ni base). it can. Here, the properties of the belt-shaped current collector are not particularly limited, such as a non-porous sheet (foil), a perforated sheet (foil), and a net-like (net-like) sheet.
It is about 00 to 400 g / m ² , more preferably about 300 to 350 g / m ² .

The electrode mixture applied to the belt-like current collector, for example, the body Ni substrate, comprises a positive electrode active material, a non-aqueous solvent such as ethylene carbonate, an electrolyte such as lithium perchlorate, and the like. In this case, a paste obtained by kneading an additive component such as a conductive material or a binder may be used.
Examples of the positive electrode active material include lithium manganese composite oxide, manganese dioxide, lithium-containing cobalt oxide, lithium-containing nickel cobalt oxide, lithium-containing amorphous vanadium pentoxide, chalcogen compound, and the like. In addition, a paste obtained by kneading nickel hydroxide, a conductive material and an additive component such as a binder may be used.

The composition of the above-mentioned electrode mixture is not particularly limited, but usually, the conductive agent 5 to 13 is added to 100 parts by weight of the electrode active material.
More preferably 7 to 8 parts by weight, binder 0.1 to 1.0
The ratio is more preferably 0.3 to 0.6 parts by weight, and the solvent is added to adjust the solid content to about 70 to 80% by weight. After the electrode mixture is applied to both the front and back surfaces of the belt-shaped current collector, the solvent in the applied layer is removed by drying.

Here, the drying means is, for example, hot air drying,
Far-infrared drying, drum contact, etc., can be performed alone or in combination.The drying temperature in the case of hot air drying varies depending on the composition of the electrode mixture, but is usually 50 to 150.
C (particularly 60 to 140 C) is preferred.

According to the first and second aspects of the present invention, when a cutting operation corresponding to a post-process is performed, the feeding and running speed of the sheet-like electrode at a constant speed is changed, and the amount of buffer in the buffer area is set as a reference. When the amount of the buffer changes to the upper limit or the lower limit, the speed of the cutting operation is easily and appropriately adjusted according to the degree of the change. In other words, while ensuring constant pressure bonding, feeding, and running of the sheet-shaped electrodes, the cutting operation is automatically slowed down and adjusted according to the buffer volume in the buffer area, and the entire line can be flowed smoothly. This improves the performance and yield.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIG.

FIG. 1 is a sectional view showing the structure of a main part of a sheet-like electrode cutting apparatus according to an embodiment. In FIG. 1, 1
a, 1b are a pair of rotary pressure rollers for rotating at a constant speed and pressing the sheet electrode 2 on the outer peripheral surface, and 3 is the rotary pressure roller.
A buffer amount detecting section for detecting the buffer amount of the sheet-shaped electrode 2 which has passed through 1a and 1b and pressed, and 4 is an electrode cutting section for cutting the sheet-shaped electrode 2 having passed through the buffer amount detecting section 3 to a predetermined length. A driving mechanism 5 drives and operates the electrode cutting mechanism 4.

The rotary pressure rollers 1a and 1b are made of, for example, stainless steel having a diameter of about 200 mm and a length of about 200 mm.
The outer peripheral surface rotates at a constant speed of about 10 m / min. The buffer amount detector 3 is disposed between the rotary pressure rollers 1a and 1b and the electrode cutting mechanism 4 (buffer region), and detects the buffer amount (the degree of slack) of the sheet-like electrode 2 in this buffer region. It detects and outputs a signal corresponding to the buffer amount. here,
The buffer amount detection unit 3 has a configuration in which a pair of the light emitting element and the light receiving element is arranged along the traveling direction of the sheet-like electrode 2 and is vertically stepped at a constant interval (for example, about 15 to 20 cm). I have.

A pair of the light emitting element 3a and the light receiving element 3a 'is used as a reference buffer amount detector A, a pair of the light emitting element 3b and the light receiving element 3b' is used as a medium buffer amount detector B, and the light emitting element 3c and the light receiving element are used.
The pair of 3c 'is a lower limit buffer amount detector C, and the pair of the light emitting element 3d and the light receiving element 3d' is an upper limit buffer amount detector D.

The plurality of buffer amount detectors A, B,
C and D detect a change in the buffer amount with respect to the reference buffer amount between the rotary press rollers 1a and 1b and the electrode cutting mechanism 4, and output a detection signal based on the detection of the buffer amount. The output of the detection signal is input to a control mechanism 6 for controlling the driving mechanism 5, and the input is controlled to control the driving mechanism 5 to operate the electrode cutting mechanism 4 at multiple speeds. Here, the detection signals of the buffer amount detectors A, B, C, and D are arranged such that the upper side has priority in the order of the buffer amount detectors D, A, B, and C.

In FIG. 1, reference numeral 7 denotes a feeder interposed between the buffer area and the electrode cutting mechanism 4 to assist the buffer action in the buffer area.
9 is a guide roller.

Next, the operation of the cutting apparatus will be described.

An electrode mixture containing an electrode active material is applied to the surface of the belt-shaped current collector and dried. The sheet electrode is supplied to a pair of rotary pressure rollers 1a and 1b which rotate at a constant speed. While the sheet-shaped electrode is pressed between the outer peripheral surfaces of the pressure rollers 1a and 1b, the sheet-shaped electrode is supplied to the electrode cutting mechanism 4 via the buffer area in which the buffer amount detection unit 3 is provided and travels. Here, the buffer amount of the sheet-like electrode 2 traveling through the rotary pressure roller with the constant speed rotation of the rotary pressure rollers 1a and 1b is within the reference range detected by the reference buffer amount detector A. , The electrode cutting mechanism 4 set and controlled in advance
The intermittent advance / retreat / drive of the cutting blade 4a cuts and separates the sheet electrode 2 which is sequentially supplied / run to a desired size.

When the buffer amount of the sheet-like electrode 2 becomes large and is within the range detected by the middle buffer amount detector B for the first time, the output signal of the middle buffer amount detector B is output from the control mechanism 6. And the driving speed of the driving mechanism 5 for intermittently moving the cutting blade of the electrode cutting mechanism 4 is changed to a medium speed, so that the sheet-like electrodes 2 sequentially supplied and run are cut and separated into desired dimensions.

Similarly, when the value falls within the range detected by the lower limit buffer amount detector C, the lower limit buffer amount detector C
Is input to the control mechanism 6 and the drive speed of the drive mechanism 5 for intermittently moving the cutting blade of the electrode cutting mechanism 4 is changed at a high speed, while being detected by the upper limit buffer amount detector D. The output signal of the upper limit buffer amount detector D is input to the control mechanism 6, and the drive speed of the drive mechanism 5 for intermittently moving the cutting blade of the electrode cutting mechanism 4 is changed to a low speed.

The sheet amount of the sheet-shaped electrode, which passes through the above-mentioned constant-speed rotary pressure rollers 1a and 1b and is supplied / run at a constant speed, has a buffer amount that fluctuates with respect to the reference buffer amount due to a trouble in a later process. In this case, the fluctuation amount is detected by the buffer amount detection unit 3, and the operation speed in the post-process is easily switched to the multi-stage speed in conjunction with the fluctuation of the buffer amount, so that the smooth flow of the line is maintained. . That is, even if a difference in the driving speed occurs between the rotary press rollers 1a and 1b and the electrode cutting mechanism 4 and the buffer amount (slack amount) changes, the driving speed of the electrode cutting mechanism 4 corresponds to the change amount. Is adjusted appropriately to high or low speed. Therefore, occurrence of troubles due to the fluctuation of the buffer amount (slack amount) is prevented, and the yield and mass productivity are improved.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention. For example, the number and intervals of the buffer amount detectors may be increased or decreased, and the material and structure of the rotary pressure roller may be changed to other materials and dimensions. Since the buffer amount detector only needs to detect a change in the buffer amount (slack amount), the buffer amount detector may be arranged in a direction crossing the sheet electrode to be supplied and run.

[0033]

As described above, according to the first and second aspects of the present invention, the driving speed difference of the electrode cutting mechanism is generated with respect to the constant-speed rotary pressure roller, and the buffer amount (the amount of slack) is increased. ) Varies, the operation and operation of the electrode cutting mechanism are appropriately adjusted in multiple stages according to the amount of the variation.
Therefore, occurrence of troubles in workability and quality due to the fluctuation of the buffer amount (slack amount) is prevented or avoided, and a highly reliable electrode can be provided with high yield.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a main part of a sheet-shaped electrode cutting device according to an embodiment.

[Explanation of symbols]

 1a, 1b: Constant-speed rotation type pressure roller 2: Sheet electrode 3: Buffer amount detector 3a, 3b, 3c, 3d: Light emitting element 3a ', 3b', 3c ', 3d': Light receiving Element 4: Electrode cutting mechanism 5: Driving mechanism 6: Control mechanism A: Reference buffer detector B: Middle buffer detector C: Lower buffer detector D: Upper buffer detector

Claims (2)

[Claims] 1. A pair of rotary pressure rollers for rotating at a constant speed and pressing a sheet electrode on an outer peripheral surface thereof, and a buffer amount detecting unit for detecting a buffer amount of the sheet electrode passing through the rotary pressure roller. An electrode cutting mechanism that cuts the sheet-shaped electrode that has passed through the buffer amount detection unit to a predetermined length, and a sheet-shaped electrode cutting device that includes a driving mechanism that drives and operates the electrode cutting mechanism, The buffer amount detector is configured to control a plurality of buffer amount detectors respectively corresponding to a change in the buffer amount based on a fixed buffer amount, and a driving mechanism corresponding to a detection signal of the buffer amount detector. And a control mechanism for operating the electrode cutting mechanism at multiple speeds. 2. The sheet electrode cutting apparatus according to claim 1, wherein a plurality of buffer amount detectors are arranged stepwise along the running direction of the sheet electrode.