JP5023549B2 - Method and apparatus for applying electrode mixture paste - Google Patents

Description

  The present invention relates to a method and an apparatus for applying an electrode mixture paste onto a core material made of an apertured metal thin plate, and more particularly to a method for improving the running of the electrode mixture paste.

  Batteries such as alkaline storage batteries and lithium ion secondary batteries are widely used as power sources for portable devices, electric tools, or electric vehicles. Above all, the use of nickel-metal hydride storage batteries, which have a relatively high energy density and excellent durability, is expanding mainly in power sources for electric vehicles.

  In general, nickel-metal hydride storage batteries consist of a positive electrode formed by filling a three-dimensional metal porous body with nickel hydroxide or the like, a perforated metal thin plate such as punching metal (hereinafter simply referred to as “core material”), a hydrogen storage alloy, and the like. And a negative electrode formed by applying an electrode mixture paste made of Above all, the negative electrode can be continuously produced due to its construction method, and is attracting attention as a highly efficient process. Specifically, a method has been proposed in which after a core material is immersed in an electrode mixture paste, the amount of the electrode mixture paste applied is adjusted to form a paste application sheet.

This paste-coated sheet is generally run by using the core material exposed portions at both ends where the electrode mixture paste is not placed after the electrode mixture paste is placed except for both ends in the width direction of the core material. is there. Specifically, in order to correct the meandering caused by the non-uniformity of the electrode mixture paste and the non-linearity inherent in the core material, the sandwich is inclined so as to open slightly outward rather than parallel to the running direction. A method of correcting the meandering by applying tension to the paste coating sheet in a balanced manner by sandwiching the exposed portion of the core material with a roller and repeating pinching and releasing by the sandwiching roller according to the amount of meandering of the paste coating sheet. (For example, Patent Document 1).
Japanese Patent Laid-Open No. 9-017419

  In general, the electrode mixture paste of a nickel metal hydride storage battery has a large specific gravity (for example, about 8 g / ml in the case of a hydrogen storage alloy). The weight of is considerably increased. As described above, when an intermittent operation (repeating pinching and releasing by a pinching roller) as in Patent Document 1 is performed on a paste coating sheet having a large weight per unit area of the coating portion, the paste is applied each time this operation is performed. Vibration is generated in the application sheet, and the electrode mixture paste before drying flows to decrease the application accuracy. Moreover, since the operation is intermittent as described above, it is difficult to smoothly correct the meandering.

  The present invention has been made in view of the above-mentioned problems, and by smoothly correcting meandering when applying and drying an electrode mixture paste containing a material having a high specific gravity, the electrode combination is corrected while accurately correcting meandering. An object of the present invention is to provide a stable electrode mixture paste application method capable of avoiding a decrease in application accuracy due to the flow of the agent paste.

In order to solve the above problems, the electrode mixture paste application method of the present invention includes a first step of unwinding a core material wound in a coil shape, and a paste in which the electrode material paste is placed on the core material A second step of forming a coating sheet, a third step of adjusting the coating amount of the electrode mixture paste, and the core material exposed portions provided at both ends in the width direction of the core material in the second or third step. While sandwiching both sides continuously from the front and back with at least one pair of sandwiching rollers, the angle of the sandwiching roller with respect to the paste coating sheet is changed according to the meandering amount detected by the meandering detection unit to meander the paste coating sheet. It consists of a fourth step of straightening, a fifth step of drying the paste coated sheet, and a sixth step of winding the paste coated sheet into a coil shape. In the fourth step, the sandwiching rollers are set to 5 ° or less. Range In which it characterized in that spread along the traveling direction of the paste-coated sheets.

  In addition, as a means for embodying the above-described coating method, the electrode mixture paste coating apparatus of the present invention includes an uncoiler that winds a core material wound in a coil shape, and an electrode mixture paste placed on the core material. In the paste application part to be a paste application sheet, the application amount adjustment part for adjusting the application amount of the electrode mixture paste, the meandering detection part for detecting the meandering amount of the paste application sheet, and the paste application part or the application amount adjustment part With respect to the paste application sheet corresponding to the meandering amount detected by the meandering detection unit while continuously sandwiching both the core material exposed portions provided at both ends in the width direction of the core material from the front and back with at least one pair of sandwiching rollers It consists of a meandering correction part that corrects the meandering of the paste application sheet by changing the angle of the sandwiching roller, a drying part, and a coiler part that winds the paste application sheet after drying into a coil shape. In the meandering correction unit, a nip roller each other, characterized in that spread along the traveling direction of the paste coated sheet within the range of 5 ° or less.

  By switching the meandering correction method from repeating pinching and releasing by the pinching roller to changing the angle of the pinching roller with respect to the paste application sheet that is continuously held, the traveling direction of the paste application sheet changes smoothly during correction. Therefore, a decrease in coating accuracy due to the flow of the electrode mixture paste can be avoided, and accurate meandering correction can be performed.

  As described above, according to the present invention, even if the electrode mixture paste contains a material having a high specific gravity, the flow of the electrode mixture paste can be avoided by smoothly controlling the meandering. It is possible to provide a paste application method, and it is possible to supply electrodes of batteries such as nickel metal hydride storage batteries with high application accuracy.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  1st invention unwinds the core material wound by coil shape, the 2nd process of putting electrode mixture paste on a core material, and making it a paste application sheet, and electrode mixture paste In the second step or the third step, the core material exposed portions provided at both ends in the width direction of the core material are continuously connected from the front and back with at least one pair of sandwiching rollers. A fourth step of correcting the meandering of the paste coating sheet by changing the angle of the sandwiching roller with respect to the paste coating sheet in accordance with the meandering amount detected by the meandering detection unit, and a fifth step of drying the paste coating sheet. And the sixth step of winding the paste-applied sheet in a coil shape. In the fourth step, the sandwiching rollers are spread within the range of 5 ° or less along the traveling direction of the paste-applied sheet. With features That relates to a method of applying the electrode mixture paste.

In addition, the second invention includes an uncoiler portion that winds a core material wound in a coil shape, a paste application portion that places an electrode mixture paste on the core material to form a paste application sheet, and application of the electrode mixture paste Both a coating amount adjusting unit for adjusting the amount, a meandering detecting unit for detecting the meandering amount of the paste coating sheet, and a core material exposing portion provided at both ends in the width direction of the core material in the paste coating unit or the coating amount adjusting unit Meandering to correct the meandering of the paste application sheet by changing the angle of the pinching roller relative to the paste application sheet in accordance with the amount of meandering detected by the meandering detection unit It consists of a straightening part, a drying part, and a coiler part that winds the paste application sheet after drying into a coil shape. In the meandering straightening part, the nipping rollers are moved within a range of 5 ° or less. That spread along the running direction of the preparative coating sheets for the coating apparatus of the electrode mixture paste according to claim.

  FIG. 1 is a schematic view showing an example of an electrode mixture paste coating apparatus according to the present invention. The coiled core material 2 made of an open metal thin plate is unwound by the uncoiler part 1 and then guided to the paste application part 4 filled with the electrode mixture paste 5, and the electrode mixture paste is placed on the core material 2. 5 becomes a paste application sheet 6. Subsequently, the application amount of the paste application sheet 6 is adjusted via the application amount adjusting unit 3, and the core material exposed portions 9 are provided at both ends in the width direction. The core material exposed portion 9 is sandwiched from the front and back by a pair of sandwiching rollers 10 after passing through the coating amount adjusting portion 3. Here, by spreading the pair of sandwiching rollers 10 along the traveling direction of the paste application sheet 6 within a range of 5 ° or less, an appropriate tension is applied to the paste application sheet 6 to roughly suppress meandering. Yes. However, the meandering control based on the distortion inherent in the core material 2 is impossible simply by spreading the pair of sandwiching rollers 10 along the traveling direction of the paste application sheet 6. Accordingly, the sandwiching roller 10 is combined with the control unit 11 to form a meandering correction unit 12, and the control unit 11 corresponds to the meandering amount of the paste application sheet 6 detected by the meandering detection unit 13 provided in front of the meandering correction unit 12. By changing the angle of the sandwiching roller 10 with respect to the paste application sheet 6, the meandering of the paste application sheet 6 is accurately corrected. The paste application sheet 6 having improved traveling properties in this way is guided to the drying unit 7 and then wound into a coil by the coiler unit 8.

  FIG. 2 is an enlarged schematic view of the meandering correction unit 12 and the meandering detection unit 13 in the electrode mixture paste coating apparatus of the present invention. A core material exposed portion 9 is provided at both ends in the width direction of the paste application sheet 6 that has passed through the coating amount adjusting unit 3, and a pair of sandwiching rollers 10 that connect the core material exposed portion 9 with links 11 c from the front and back sides. It is sandwiched continuously. Here, the pair of sandwiching rollers 10 are spread within a range of 5 ° or less from the third step to the fifth step (in the V-shaped direction in FIG. 2). By sandwiching the core material exposed portion 9 with the sandwiching roller 10 so that the paste application sheet 6 spreads along the traveling direction in this way, tension can be applied to the paste application sheet 6 in a balanced manner. A meandering detection unit 13 is provided in front of the pinching roller 10 to detect a deviation from the reference value at the right end of the paste application sheet 6. If the meandering detection unit 13 detects that the paste application sheet 6 meanders from right to left, the actuator 11b is actuated by a command from the control unit 11a, and the right and left nipping rollers 10 are moved to the right side through the link 11c. Tilt to.

  Since the running direction of the paste coating sheet 6 changes smoothly during the meandering correction by changing the angle of the sandwiching roller 10 with respect to the paste coating sheet 6 while continuously sandwiching the core exposed portion 9, the electrode mixture paste A decrease in coating accuracy due to the flow of 5 on the core material 2 can be avoided, and accurate meandering correction can be achieved.

  If the angle between the sandwiching rollers 10 exceeds 5 °, the amount of meandering increases due to the following three problems, which is not preferable. The first problem is that excessive tension acts on the paste application sheet 6. A second problem is that the wear of the pinching roller 10 is accelerated by an increase in the amount of sliding between the paste application sheet 6 and the pinching roller 10. The third problem is that it becomes necessary to sharply correct the meandering due to an increase in the amount of slip between the paste application sheet 6 and the sandwiching roller 10, and it becomes difficult to control.

  1 and 2 show a form in which the application amount adjusting unit 3 and the paste application unit 4 are separated, but the application amount adjusting unit 3 and the paste application unit 4 are integrated like a die coater. Even in this case, it goes without saying that the effect of the present application is exhibited.

Below, the Example of this invention is described using the negative electrode (hydrogen storage alloy electrode) of a nickel hydride storage battery. However, the present invention is not limited to this example as long as the core material is an apertured metal thin plate. For example, a sintered substrate that is a precursor of a sintered nickel positive electrode of an alkaline storage battery, an aperture It can also be applied to positive and negative electrodes of lithium polymer batteries using lath metal as a thin metal plate.

(Example)
As the core material 2, an iron punching metal (total length of 200 m of one coil) plated with nickel having a thickness of 60 μm, a width of 300 mm, a punching hole diameter of 1 mm, and an opening ratio of 42% is wound with a balance of tension in the width direction. Thus, the meandering amount was adjusted in advance to be 0.02 to 0.03 mm / m (4 to 6 mm at 200 m).

On the other hand, a hydrogen storage alloy powder represented by a composition formula MmNi _3.55 Co _0.75 Mn _0.4 Al _0.3 was pulverized in water by a wet ball mill to an average particle size of 30 μm. After this alloy powder was immersed in an alkaline aqueous solution and subjected to surface treatment, 10 kg of a carboxymethyl cellulose aqueous solution having a solid content ratio of 1.5% and 0.4 kg of ketjen black were added to and kneaded with 100 kg of this hydrogen storage alloy powder. An electrode mixture paste 5 was prepared by adding 1.75 kg of an aqueous solution of styrene-butadiene copolymer rubber particles having a solid content ratio of 40% and stirring.

  Using this coating apparatus shown in FIG. 1, the electrode mixture paste 5 is scraped off by 20 mm as set values from both ends so that the total thickness after coating is 260 mm and the total thickness after coating is 260 μm. While producing the exposed portion 9, the paste was applied to both surfaces of the core material 2 described above at a speed of 5 m / min to produce a paste application sheet 6. The meandering correction was carried out using the method described in detail in the description of the first invention (the angle between the pinching roller 10 and the paste application sheet 6 was 5 °).

  After coating for 200 m, the width of the core material exposed portions 9 at both ends was measured, and as a result, the maximum deviation value from the set value of 20 mm was 0.05 mm. In addition, after punching out the application part of the last part of the paste application sheet 6 (a part at the end of application) with a punch having a diameter of 30 mm in the width direction, the standard deviation of the application amount of the electrode mixture paste 5 after drying is weighted. % Was found to be σ = 0.3%.

(Comparative example)
A paste-coated sheet 6 was produced in the same manner as in Example 1 except that the meandering correction method was changed to that of Patent Document 1 with respect to Example 1. Specifically, when the meandering detection unit 13 detects that the paste application sheet 6 meanders from right to left, only the right holding roller 10 is released so that the core material exposed part 9 is not pinched, and the meandering After the correction was made, control was performed so that the core material exposed portion 9 was held by the right holding roller 10 again.

  As a result of measuring the width of the core material exposed portions 9 at both ends after coating over 200 m, the maximum deviation value from 20 mm which is the set value was 0.52 mm. After punching out a total of 6 portions with a 30 mm diameter punch in the width direction in the last applied portion of the paste applied sheet 6, the standard deviation of the applied amount in the electrode mixture paste 5 after drying was determined by weight%. = 1.4%.

As described above, as the operation of the meandering correction unit 12, the core material exposure unit 9 is continuously sandwiched from the front and back by the sandwiching roller 10, and according to the meandering amount of the paste application sheet 6 detected by the meandering detection unit 13. The embodiment in which the angle between the sandwiching roller 10 and the paste application sheet is changed by the method of the present invention to correct the meandering is a method of correcting the meandering without continuously sandwiching the core exposed portion 9 by the sandwiching roller 10. Compared to the comparative example taken, the accuracy of the width dimension of the core material exposed portion 9 was high, and the variation in the coating amount was greatly reduced. This is because two problems (running) occur when trying to correct meandering by intermittent movement in the paste application sheet 6 holding the electrode mixture paste 5 containing a hydrogen storage alloy having a high specific gravity of about 8 g / ml. This is considered to be due to the suppression of the deterioration of the properties and the flow of the electrode mixture paste 5).

  According to the present invention, since an electrode mixture paste containing a material having a high specific gravity can be mass-produced with high accuracy, the present invention is highly applicable and useful as an electrode manufacturing technique for various batteries.

Schematic which shows an example of the coating device of the electrode mixture paste in this invention Schematic which expanded the meandering correction part and meandering detection part in the coating device of the electrode mixture paste in this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Uncoiler part 2 Core material 3 Application | coating amount adjustment part 4 Paste application part 5 Electrode mixture paste 6 Paste application sheet 7 Drying part 8 Coiler part 9 Core material exposure part 10 Clamping roller 11 Control part 11a Control unit 11b Actuator 11c Link 12 Meander Correction unit 13 Meander detection unit

Claims (2)

It is a coating method of an electrode mixture paste in which a core material made of an open metal thin plate is run and an electrode mixture paste is applied on the core material,
A first step of unwinding the core material wound in a coil shape;
A second step of placing the electrode mixture paste on the core material to form a paste application sheet; a third step of adjusting the amount of the electrode mixture paste applied;
In the second or third step, the meandering detection unit detects both of the core material exposed portions provided at both ends in the width direction of the core material from the front and back continuously with at least one pair of clamping rollers. A fourth step of correcting the meandering of the paste application sheet by changing the angle of the sandwiching roller with respect to the paste application sheet according to the amount of meandering;
A fifth step of drying the paste application sheet;
A sixth step of winding the paste application sheet into a coil shape,
In the fourth step, the electrode mixture paste coating method is characterized in that the sandwiching rollers are spread along the traveling direction of the paste coating sheet within a range of 5 ° or less. An electrode mixture paste coating apparatus for running a core material made of an open metal thin plate and applying an electrode mixture paste on the core material,
An uncoiler that unwinds the core material wound in a coil shape;
A paste application part on which the electrode mixture paste is placed on the core material to form a paste application sheet;
An application amount adjusting unit for adjusting the application amount of the electrode mixture paste;
A meandering detection unit for detecting a meandering amount of the paste application sheet;
In the paste application unit or the application amount adjusting unit, the meandering detection unit is configured to continuously hold both core material exposed portions provided at both ends in the width direction of the core material from the front and back by at least one pair of clamping rollers. A meandering correction unit that corrects the meandering of the paste application sheet by changing the angle of the sandwiching roller with respect to the paste application sheet according to the amount of meander detected by
A drying section;
It consists of a coiler part that winds the paste application sheet after drying into a coil shape,
In the meandering correction section, the electrode mixture paste coating apparatus is characterized in that the sandwiching rollers are spread along the traveling direction of the paste coating sheet within a range of 5 ° or less.