JPH07326338A - Manufacture of battery - Google Patents

Abstract

PURPOSE:To make an electrolyte uniformly penetrate into an electrode group in a short time by rotating an armor can with a central axis as the rotating axis, pressurizing the electrolyte injected by the centrifugal force from the center toward the outer circumference, and making it forcedly penetrate. CONSTITUTION:A battery is rotated with a vertically extended central axis as the rotating axis, or rotated around its own axis. The centrifugal force acts on the battery rotated in this direction from the center of the battery toward the outer circumference as shown by the arrow. The centrifugal force pressurizes the electrolyte injected into an armor can 7 from the center toward the outer circumference. The electrolyte pressurized in this direction is never differed between the upper and lower parts of an electrode group 8. Thus, it is never caused that the electrolyte injected into the armor can 7 is collected to the bottom part and does not penetrate into the upper part of the electrode group 8 as in the past, and the electrolyte is uniformly dispersed. When it is made to penetrate into the electrode group having a center hole 8A, particularly, the electrolyte of the center hole 8A can be made to uniformly penetrate into the electrode group 8.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for manufacturing a battery,
In particular, the present invention relates to a battery manufacturing method that utilizes centrifugal force to rapidly permeate an electrolytic solution into an electrode group.

[0002]

2. Description of the Related Art A battery is manufactured by inserting an electrode group into an outer can and then injecting an electrolytic solution. It is important that the injected electrolyte is quickly permeated into the electrode group. This is because if it takes time to penetrate, productivity will decrease. In particular, for a nickel-hydrogen battery that uses a hydrogen storage alloy for the electrode plate, it is important to shorten the liquid injection time in order to achieve high rate discharge characteristics. If it takes time for the electrolyte to penetrate,
This is because the hydrogen storage alloy that is the electrode plate oxidizes and the performance deteriorates.

Techniques utilizing centrifugal force in order to reduce the permeation time of the electrolytic solution are described in JP-A-62-139247 and JP-A-2-22983. The method described in these publications uses the device shown in FIG. 1 to permeate an electrolyte solution into an electrode group. In the apparatus shown in this figure, a liquid injection pipe 3 and a battery holder 4 are tiltably connected to both ends of an arm 1 rotated in a horizontal plane via tilt pins 2. A vertical rotating shaft 5 is connected to the center of the arm 1, and the rotating shaft 5 is connected to a motor 6. When the motor 6 rotates the rotary shaft 5, the arm 1 is rotated in a horizontal plane, and the holding bases 4 connected to both ends of the arm 1 are horizontally tilted and rotated in a state of being swung to the horizontal plane. Centrifugal force acts on the battery fixed to the rotating holding table 4 in a direction indicated by an arrow. The centrifugal force pressurizes the electrolytic solution filled in the outer can 7 to forcefully penetrate into the electrode group 8.

[0004]

The method of pressurizing the electrolytic solution by centrifugal force using the apparatus shown in FIG. 1 is faster than the method of injecting the electrolytic solution and then leaving it stationary. Can penetrate into the electrode group. Therefore, the battery can be efficiently mass-produced, and the nickel-hydrogen battery can prevent the oxidation of the hydrogen storage alloy.

However, when the electrolytic solution is permeated into the electrode group using the apparatus shown in FIG. 1, the direction of the electrolytic solution is toward the bottom of the outer can 7 as indicated by the arrow in FIG. There is a drawback that it is difficult to sufficiently penetrate into the upper part of the electrode group 8 shown by cross hatching in the figure. For this reason, it takes time to sufficiently permeate the electrolytic solution into the entire electrode group 8, which causes a decrease in the productivity of batteries that are mass-produced.

Further, the nickel-hydrogen battery using a hydrogen storage alloy in the electrodes has a drawback that it takes a long time to sufficiently permeate the electrolytic solution into the electrode group and the initial charging cannot be performed immediately after pouring the electrolytic solution. It was The time required for initial charging causes the hydrogen storage alloy to oxidize before being charged, resulting in deterioration of battery performance. The hydrogen storage alloy hardly oxidizes in a state where hydrogen is stored by initial charge, but an environment in which the hydrogen storage alloy is liable to oxidize is obtained when the electrolyte is injected and the hydrogen storage alloy comes into contact with the solution. For this reason, in a battery using a hydrogen storage alloy, it is important to shorten the time from the injection of liquid to the initial charging in order to reduce deterioration of battery performance. When the initial charge is performed in a state where the electrolytic solution does not sufficiently penetrate into the electrode group, all the electrode groups are charged in a state where they do not come into contact with the electrolytic solution in an ideal state, so that hydrogen cannot be uniformly stored in the hydrogen storage alloy, The internal pressure of the battery rises.

The present invention was developed for the purpose of more efficiently permeating the electrolytic solution into the electrode group by utilizing centrifugal force. An important object of the present invention is to provide an electrolytic solution injected into an outer can. Another object of the present invention is to provide a method for manufacturing a battery that can uniformly penetrate the inside of the electrode group in a short time.

[0008]

The method of manufacturing a battery of the present invention has the following constitution in order to achieve the above-mentioned object.
The battery manufacturing method is an improved method of injecting the electrolytic solution into the outer can 7 into which the electrode group 8 is inserted and forcibly permeating into the electrode group 8 using the centrifugal force of the injected electrolytic solution. is there. In order to allow the electrolytic solution to permeate the electrode group 8 uniformly in a short time, when the electrolytic solution permeates into the electrode group 8, the manufacturing method of the present invention is
The battery is rotated about a central axis extending in the longitudinal direction as a rotation axis. In this specification, rotation in this direction is referred to as rotation. As shown in the arrow in FIG. 3, the electrode group 8 built in the outer can 7 that rotates is arranged from the center of the battery to the outer can 7.
The electrolytic solution is permeated into the electrode group 8 by the centrifugal force toward the outer periphery of the electrode group 8. The centrifugal force acting in this direction does not forcibly move the electrolytic solution below the outer can 7 as indicated by the arrow in FIG. The electrolyte is pressed from the center of the battery toward the outer periphery to forcefully penetrate. The cylindrical battery has a central hole 8 in the electrode group 8.
Since there is A, it has a feature that an electrolyte can be injected here to penetrate the electrode group 8 in an ideal state. However, the battery manufacturing method of the present invention does not specify a battery in which the electrolytic solution permeates the electrode group by centrifugal force as a cylindrical battery. It goes without saying that prismatic batteries can also be used as batteries.

Furthermore, the method of manufacturing the battery of the present invention is as shown in FIG.
The centrifugal force is applied from the center of the battery to the outer periphery as indicated by the arrow in Fig. 4, but it goes without saying that the centrifugal force can also be applied in the longitudinal direction as indicated by the arrow in Fig. 4. . As shown by the arrow in FIG. 4, in order to apply a centrifugal force to both the vertical direction and the radial direction, the central axis of the battery is used as the rotation axis, and the axis orthogonal to the central axis of the battery is rotated as the rotation axis. In this specification, rotation about an axis orthogonal to the center axis of the battery as a rotation axis is referred to as revolution.

A method for producing a battery according to a second aspect of the present invention is a method for producing a battery using a hydrogen storage alloy as an electrode. Batteries that use hydrogen storage alloy for the electrodes are electrode group 8
The electrolytic solution is injected into the outer can 7 in which is inserted, and after the solution is injected and permeates the electrode group 8, the electrolytic solution is forcibly applied to the electrode group 8 by using centrifugal force until the initial charging. Permeate into.

[0011]

In the method of manufacturing a battery of the present invention, as shown in FIG. 3, the battery is rotated, that is, rotated about a central axis extending in the longitudinal direction of the battery as a rotation axis. A centrifugal force acts on the battery rotated in this direction from the center of the battery toward the outer periphery, as indicated by the arrow. The centrifugal force pressurizes the electrolytic solution injected into the outer can 7 from the center toward the outer periphery. The electrolytes pressurized in this direction cannot be different above and below the electrode group 8. Therefore, unlike the conventional manufacturing method, it is possible to prevent the electrolyte solution poured into the outer can 7 from being concentrated in the bottom portion and permeating into the upper portion of the electrode group 8 and being dispersed uniformly. In particular, as shown in FIG. 3, when the electrode group 8 having the central hole 8A is permeated, the electrolytic solution in the central hole 8A can be uniformly permeated into the electrode group 8.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. However, the examples described below exemplify a battery manufacturing method for embodying the technical idea of the present invention, and the present invention does not specify the battery manufacturing method to the following.

A spiral electrode group is manufactured as follows. The electrode group is manufactured by stacking and winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween. The battery manufacturing method of the present invention does not specify the type of battery to be manufactured. Since the manufacturing method of the present invention is characterized in that the electrolytic solution is permeated into the electrode group by utilizing the centrifugal force, the electrolytic solution is centrifugally applied to the electrode group regardless of the material or structure of the electrode group. This is because it can efficiently penetrate into. In order to specifically exemplify the manufacturing method of the battery, the manufacturing method will be described below taking a nickel-hydrogen battery having a spiral electrode group as an example. However, it goes without saying that the manufacturing method of the present invention does not specify the type of battery as a nickel-hydrogen battery which will be described in detail below. By permeating, nickel-cadmium batteries and lithium-ion secondary batteries can also be manufactured. Furthermore, the manufacturing method of the present invention does not specify the electrode group as a spiral type, but can also manufacture a battery having a laminated structure in which a positive electrode plate and a negative electrode plate are laminated via a separator.

A nickel-hydrogen battery is manufactured by the following steps. (1) Production and pulverization process of hydrogen storage alloy Misch metal, which is a rare earth metal, cobalt, aluminum, and manganese are weighed and mixed to a predetermined weight, put in a crucible and fired in a high-frequency melting furnace. to prepare a hydrogen storage alloy whose composition formula is represented by _{MmNi 3.4 Co 0.8 Al 0.2 Mn 0.6} . The obtained alloy ingot of the hydrogen storage alloy is crushed in an inert gas. The crushed hydrogen storage alloy has an average particle size of 150 μm or less.

(2) Step of manufacturing negative electrode plate A powder of hydrogen-absorbing alloy that has been ground is mixed with a predetermined amount of an additive to form an active material, and this active material is mixed with water and polytetrafluoroethylene powder as a binder. Knead into a paste. The addition amount of the polytetrafluoroethylene powder, which is a binder, is 5% by weight with respect to the active material. The obtained paste is pressure-bonded to both sides of a current collector which is a punching metal, and then pressed to manufacture a negative electrode plate.

(3) Step of producing electrode group A positive electrode plate, which is a sintered nickel electrode, and a negative electrode plate produced in the above step are laminated with a separator made of non-woven fabric, which is wound and spirally wound. A group of electrodes.

(4) Step of injecting liquid into the outer can in which the electrode group has been inserted The spiral electrode group manufactured in the above step is inserted into a cylindrical AA-type outer can to prepare a test cell. To manufacture. Under the conditions shown below in the test cell thus manufactured,
A nickel-hydrogen battery was manufactured by injecting an electrolytic solution, which is a KOH aqueous solution having a specific gravity of 1.3, and allowing the electrolytic solution to permeate the electrode group and immediately closing the openings. The theoretical capacity of the nickel-hydrogen battery thus produced is 1000 mA.

Batteries produced by the method of the present invention (A1 to A6) under the following conditions, in which the electrolytic solution is injected into the outer can inserted in the electrode group and the injected electrolytic solution is allowed to penetrate into the electrode group.
And the batteries (X1 to X2) manufactured by the conventional method were prototyped and their characteristics were measured.

However, the manufacturing method according to the embodiment of the present invention is
The rotation speed for rotating the battery was set to 2700 rpm, and the rotation time was set to 10 seconds. In the conventional manufacturing method, the rotation speed for revolving the battery was 500 rpm, and the rotation time was set to the same 10 seconds. The reason for increasing the rotation speed of the battery of the present invention is that the centrifugal force becomes weak at the same rotation speed because the rotation radius is small. The centrifugal force increases in proportion to the product of the square of the number of revolutions and the radius of gyration. The radius of an AA battery is about 7 mm. On the other hand, in the conventional method, the distance from the center of the rotating shaft to the bottom surface of the battery is 200 mm. Therefore, in the method of the present invention, the centrifugal force was adjusted to be approximately constant by setting the rotation speed to (200/7) ^1/2 times that of the conventional method to about 2700 rpm.

An apparatus for injecting an electrolytic solution into an outer can and rotating it is shown in FIGS. 5 and 6. The device shown in FIG.
0 is fixed to the base 9, and the rotary base 11 for fixing the outer can 7 is fixed to the rotary shaft of the motor 10. The turntable 11 has a built-in cylinder 12 for holding the outer can 7. A coupling 13 is connected to the rotary table 11 in order to supply pressurized air to the cylinder 12 of the rotary table 11.
The coupling 13 supplies the pressurized air, which is press-fitted into the supply pipe, to the cylinder 12. The turntable 11 holds the outer can 7 in a vertical posture with respect to the center. A liquid injection pipe 3 for injecting an electrolytic solution is arranged downward at the center of and above the outer can 7 to be sandwiched. In this device, the outer can 7 is clamped on the turntable 11, and the motor 10 rotates the turntable 11 to rotate the outer can 7.
To rotate. The liquid injection pipe 3 injects the electrolytic solution into the center of the outer can 7 into which the electrode group 8 is inserted. The apparatus shown in this figure can inject liquid while rotating the outer can 7.

The apparatus shown in FIG. 6 can revolve while rotating the outer can. In this device, a rotation motor 14 is connected to a tip of an arm 1 rotated in a horizontal plane so as to be tiltable via a tilting pin 2. The liquid injection pipe 3 is connected to the rotation shaft of the rotation motor 14 via a coupling 15. A pinching member 16 for pinching and holding the outer can 7 is attached to the liquid injection pipe 3. The coupling 15 injects the electrolytic solution into the rotating injection pipe 3. The coupling 17 is also connected to the rotary shaft of the arm 1. The coupling 17 supplies the electrolytic solution to the rotating shaft of the arm 1.

Using the mounting shown in FIGS. 5 and 6, the battery is manufactured by injecting the electrolytic solution into the outer can in which the electrode group is inserted as follows.

Battery A1 of Example 1 When injecting liquid into the outer can in which the electrode group is inserted, the outer can is rotated at 2700 rpm with the central axis as a rotation axis to allow the electrolytic solution to permeate the electrode group. Then, a sealing plate is fixed to the outer can and the opening is closed to obtain a battery. In this method, while pouring the liquid, the outer can 7 is rotated at 2700 rpm in the direction shown in FIG.
Rotate with.

Battery A2 of Example 2 The outer can in which the electrode group was inserted was allowed to stand still to inject the liquid, and immediately after that, the outer can was rotated at 2700 rpm with the central axis as the rotation axis, and the electrolytic solution was applied to the electrode group. Infiltrate. Then, a sealing plate is fixed to the outer can and the opening is closed to obtain a battery. In this method, after pouring the liquid, the outer can 7 is moved in the direction shown in FIG.
Rotate at 700 rpm.

Battery A3 of Example 3 The outer can having the electrode group inserted therein was allowed to stand still to inject liquid, and after closing the opening of the outer can with the sealing plate, the outer can was rotated at 2700 rpm with the central axis as the rotation axis. The electrolyte is allowed to rotate to permeate the electrode group. In this method, immediately after sealing the outer can, the outer can 7 is rotated at 2700 rpm in the direction shown in FIG.

◎ Battery A4 of Example 4 The outer can in which the electrode group was inserted was injected while revolving at 500 rpm. Immediately after the injection, the outer can was rotated at 2700 rpm with the central axis as the rotation axis to remove the electrolytic solution. Permeate the electrode group. Then, a sealing plate is fixed to the outer can and the opening is closed to obtain a battery. In this method, the outer can 7 is rotated about two axes as shown in FIG.

◎ Battery A5 of Example 5 The outer can in which the electrode group was inserted was injected while revolving at 500 rpm, and the opening of the injected outer can was sealed with a sealing plate.
Immediately after that, the outer can with the center axis of rotation of 2700r
Rotate at pm to permeate the electrolyte solution into the electrode group. Also in this method, the outer can 7 is rotated about two axes as shown in FIG.

Battery A6 of Example 6 The outer can with the electrode group inserted was revolved at 500 rpm, and the outer can was rotated about the central axis of the outer can for 2700.
Rotate at rpm to inject the electrolyte. Then, the sealing plate is fixed to the outer can to close the opening. Also in this method, the outer can 7 is rotated about two axes as shown in FIG. 4, but this method causes the outer can to rotate while revolving.

The above is the manufacturing method according to the embodiment of the present invention, but the following is a method of making a prototype by the conventional method for comparison.

△ Battery X1 of Comparative Example 1 An outer can having the electrode group inserted therein is allowed to stand still to inject liquid. afterwards,
A sealing plate is fixed to the outer can and the opening is closed to form a battery. In this method, the outer can is neither rotated nor revolved, and the centrifugal force generated by the rotation is not used.

Δ Battery X2 of Comparative Example 2 An outer can in which the electrode group was inserted was poured while revolving at 500 rpm, and the electrolytic solution was permeated into the electrode group by centrifugal force. Then, a sealing plate is fixed to the outer can and the opening is closed to obtain a battery. In this method, the outer can 7 is rotated as shown in FIG.

B Battery X3 of Comparative Example 3 The battery X1 of the comparative example is allowed to stand for 1 hour to allow the injected electrolytic solution to permeate the electrode group 8. That is, the initial charging is not started until 1 hour has passed after the outer can 7 is sealed.

Battery X of Comparative Example 4 The battery X1 of Comparative Example was allowed to stand for 5 hours to allow the injected electrolytic solution to permeate the electrode group 8. That is, after charging the outer can 7, the initial charging is not started until 5 hours have passed.

B Battery X5 of Comparative Example 5 The battery X1 of Comparative Example is allowed to stand for 24 hours to allow the injected electrolytic solution to permeate the electrode group 8. That is, after the outer can 7 is sealed, the initial charging is not started until 24 hours have passed.

B Battery X6 of Comparative Example 6 The battery X2 of Comparative Example is allowed to stand for 1 hour to allow the injected electrolytic solution to permeate the electrode group 8. That is, the initial charging is not started until 1 hour has passed after the outer can 7 is sealed.

Battery X7 of Comparative Example 7 The battery X2 of Comparative Example was allowed to stand for 5 hours to allow the injected electrolytic solution to permeate the electrode group. That is, after sealing the outer can 7,
The initial charging is not started until 5 hours have passed.

Battery X8 of Comparative Example 8 The comparative battery X2 is allowed to stand for 24 hours to allow the injected electrolytic solution to permeate the electrode group. That is, after sealing the outer can 7,
The initial charging is not started until 24 hours have passed.

The batteries of Examples and Comparative Examples manufactured as described above were fully charged at 100 mA immediately after the above steps were completed, and the battery internal pressure was measured after 5 hours while continuing charging. The result was 1. Comparative batteries X1 to X8
Will start charging after leaving the outer can 7 closed for 1 to 24 hours.

[0039]

[Table 1]

As shown in this table, the batteries A1 to A6 manufactured by the method of the present invention have a lower internal pressure than the batteries X1 to X8 manufactured by the conventional method. A battery in which the internal pressure after charging is low means that the electrolyte solution is uniformly permeated into the electrode group. This is because when a battery in which the electrolytic solution is not sufficiently permeated into the electrode group is charged, electrolysis occurs inside and gas is generated, which increases the internal pressure of the battery.

As shown in this table, the batteries according to the examples of the present invention had a considerably low internal pressure of 0.101 to 0.105 MPa, whereas the battery X1 of the comparative example had an internal pressure of 0.352 MPa. And became extremely high. This is because the comparative battery X1 does not utilize the centrifugal force, and therefore the electrolytic solution is not sufficiently permeated into the electrode group. The comparative battery X2, which uses the centrifugal force to permeate the electrolytic solution, cannot sufficiently permeate the electrolytic solution above the electrode group, so the internal pressure is 0.276 MPa.
And was considerably higher than the batteries of the examples of the present invention.

When the electrolytic solution is poured into the outer can and left to stand, the electrolytic solution gradually permeates the entire electrode group.
Comparative batteries X4 and X7 show an increase in internal pressure of 0.10 after charging.
7 MPa, which is 0.107 MPa, which is lower than those of the comparative batteries X3 and X8. However, the method of allowing the electrolytic solution to penetrate into the electrode group for 1 hour or more is
It reduces the productivity of mass-produced batteries. Comparative battery X
5 and X8, when left standing for a long time, there is a drawback that the hydrogen storage alloy is oxidized before being charged and the charging efficiency is significantly reduced. In order to minimize the deterioration of the electrical characteristics of the hydrogen storage alloy and improve the productivity of the battery that is mass-produced, it is extremely important how quickly the electrolyte can penetrate into the electrode group.

[0043]

As shown in FIG. 3, the battery manufacturing method of the present invention rotates the outer can with the central axis of the battery as the axis of rotation and injects it by centrifugal force when the electrolyte is permeated into the electrode group. The liquid electrolyte is pressed from the center to the outer circumference to forcefully permeate. The electrolytic solution, which is pressurized by the centrifugal force acting in this direction, is not uniformly concentrated in the lower part of the electrode group as in the conventional case, but is uniformly dispersed vertically and is pressed to the outer periphery. Therefore, in the battery manufacturing method of the present invention, the electrolytic solution poured into the outer can can uniformly penetrate into the electrode group in a short time. Therefore, there is an excellent feature that the takt time of the battery to be mass-produced can be shortened and the high-quality battery can be efficiently mass-produced.

[Brief description of drawings]

FIG. 1 is a front view of a conventional device in which an electrolytic solution is permeated into an electrode group by centrifugal force.

FIG. 2 is a schematic sectional view showing a state in which the device shown in FIG. 1 rotates an outer can.

FIG. 3 is a schematic sectional view showing a state in which an electrolytic solution is permeated into an electrode group by a method according to an embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing a state in which an electrolytic solution is permeated into an electrode group by a method according to another embodiment of the present invention.

FIG. 5 is a partial cross-sectional front view showing an example of an apparatus used in the battery manufacturing method of the present invention.

FIG. 6 is a partial cross-sectional front view showing another example of the apparatus used in the battery manufacturing method of the present invention.

[Explanation of symbols] 1 ... Arm 2 ... Tilt pin 3 ... Injection pipe 4 ... Holding table 5 ... Rotation shaft 6 ... Motor 7 ... Exterior can 8 ... Electrode group 8A ... Center hole 9 ... Base 10 ... Motor 11 ... Rotation Base 12 ... Cylinder 13 ... Coupling 14 ... Rotation motor 15 ... Coupling 16 ... Clamping member 17 ... Coupling

Claims (2)

[Claims] 1. A method for manufacturing a battery, in which an electrolytic solution is injected into an outer can in which an electrode group is inserted, and the injected electrolytic solution is forcibly penetrated into the electrode group by using centrifugal force. In the step of infiltrating the group, the battery is rotated about the central axis extending in the longitudinal direction of the battery as a rotation axis,
A method of manufacturing a battery, wherein the electrolytic solution is permeated into the electrode group by centrifugal force from the center of the battery toward the outer can. 2. An electrolytic solution is poured into an outer can having an electrode group in which the electrode is a hydrogen storage alloy, and the electrolytic solution is charged by centrifugal force until the initial charging after the injection. In the method of manufacturing the battery forcibly permeating into the electrode, in the step of permeating the electrolytic solution into the electrode group, the battery is rotated with the central axis extending in the longitudinal direction of the battery as the rotation axis,
A method of manufacturing a battery, wherein the electrolytic solution is permeated into the electrode group by centrifugal force from the center of the battery toward the outer can.