JPH11273713A - Manufacture of battery with rolled electrode body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a separator having hydrophilic organic materials on the surfaces of fibers, and thermally deform in a short time the separator remaining in the space left after a winding core is removed without generating the decomposition, modification of the hydrophilic organic material even if the heating temperature of a through hole expanding rod is raised. SOLUTION: A separator 13 made of nylon nonwoven fabric having hydrophilic organic material on the surfaces of fibers is used, and a through hole expanding rod 20 for deforming the central part of the separator 13 to the inner circumferential wall of a space left after a winding core is removed is used. The through hole expanding rod 20 is heated to a temperature capable of thermally molding the separator 13 or higher but less than a temperature at which the hydrophilic organic material is decomposed or vaporized, then the through hole expanding rod 20 is pressed against a separator 13a remaining in a space S left after the winding core is removed for the specified short time to deform the separator 13a.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for manufacturing a battery having a spiral electrode body which is spirally wound with a separator interposed between a belt-like positive / negative electrode plate.

[0002]

2. Description of the Related Art Generally, nickel-cadmium storage batteries,
In an alkaline storage battery such as a nickel-hydride storage battery, a separator is interposed between a positive electrode plate and a negative electrode plate, and these are spirally wound to form a spiral electrode body.・ Connect the negative electrode current collector. Then, the spiral electrode body is housed in a metal outer can, and a current collecting lead extending from one current collector is welded to the lower surface of the sealing body, and then an insulating gasket is inserted into the opening of the outer can. It is configured to be hermetically closed by attaching a sealing body.

When a strip-shaped separator is interposed between a strip-shaped positive electrode plate and a strip-shaped negative electrode plate and these are spirally wound to form a spiral electrode body, for example, as shown in FIG. A core rod 1 provided with a longitudinal slit 3 passing through the center of a simple end surface 2 is used, and the slit 3 is sandwiched between the center of the band-shaped separator 4 or the end of the two band-shaped separators 4 stacked. , About 1 core rod
After the rotation, the strip-shaped positive electrode plate or the strip-shaped negative electrode plate was arranged so as to be interposed between the separators 4, and the core rod 1 was rotated and wound in a spiral shape, and then wound in the spiral shape. A method of pulling out the core rod 1 from the spiral electrode body is adopted.

[0004] When the core rod 1 is pulled out of the spirally wound spiral electrode body, the space (winding) after the core rod 1 is pulled out as shown in FIG. Core trace space) 5
The separator 4 remains at the center of the space so as to divide the space 5. For this reason, an electrode rod for spot welding a current collecting lead portion extending from one current collector of the spiral electrode body to the inner bottom surface of a metal outer can also serving as one terminal is provided in the core trace space 5. However, the separator 4 remaining so as to divide the space 5 hinders the spot welding operation, thereby complicating the spot welding operation.

[0005] Therefore, a heated through-hole expansion rod (tapered metal rod) is inserted into the core trace space, and the separator remaining in the core trace space is thermally deformed so as to extend in the direction of the inner peripheral wall of the core trace space. A method of displacing has been proposed in Japanese Patent Application Laid-Open No. Sho 58-66270 or Japanese Patent Publication No. Sho 62-43304.

[0006]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No.
In the method proposed in Japanese Patent No. 66270, since the heating temperature of the through-hole expansion rod is as low as 50 to 100 ° C., the through-hole expansion rod heated to such a temperature is inserted into the core trace space. Then, even if it is attempted to thermally deform the separator remaining in the core trace space, if the insertion time of the through-hole expansion rod is short, it is difficult to thermally deform the separator, so it is inevitably long. It is necessary to insert the through-hole expansion rod across the hole. However, when the through-hole expansion rod is inserted for a long time, there is a problem that the production efficiency is reduced.

In order to improve the production efficiency, it is conceivable to increase the heating temperature of the through-hole expansion rod and shorten the insertion time. However, the separator used in the spiral electrode body as described above is considered. Is a condition that requires low electric resistance, excellent electrolyte resistance, and good retention of electrolyte.However, in a sealed storage battery, gas permeability must be further excellent. become. By the way, in order to obtain a separator satisfying such characteristics, it is known to provide a hydrophilic organic substance on the fiber surface of the nonwoven fabric separator. In this case, a problem arises in that the hydrophilic organic substance provided on the fiber surface of the separator is decomposed, denatured, or dropped, and the effect of imparting hydrophilicity is impaired.

[0008] Since the core trace space is the most contributing space for the electrolyte to penetrate into the battery, if the hydrophilicity of the separator in this part is impaired, the electrolyte injection time becomes longer. There is also a problem that the production efficiency is reduced.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been made by using a separator having a hydrophilic organic material on the surface of a fiber to expand the pores. The object of the present invention is to make it possible to thermally deform the separator remaining in the core trace space in a short time without causing decomposition and denaturation of the hydrophilic organic substance even when the heating temperature of the rod is increased. It is.

[0010] For this reason, the method for producing a battery provided with the spiral electrode body of the present invention uses a nylon nonwoven fabric separator having a hydrophilic organic material on the fiber surface as a separator.
Using a through-hole expansion rod that displaces the separator end or center to the inner peripheral wall of the winding core trace space, the heating temperature of the through-hole expansion rod is higher than the temperature at which the separator can be thermoformed, and the decomposition or decomposition of hydrophilic organic substances is performed. A method of adjusting the temperature to a temperature equal to or lower than the evaporating temperature and displacing the through-hole expansion rod against the separator remaining in the winding core trace space for a predetermined short time is adopted.

The through-hole expansion rod is heated to a temperature not lower than the temperature at which the hydrophilic organic substance is decomposed or evaporated at a temperature higher than the temperature at which the separator can be thermoformed, and pressed for a predetermined short time on the separator remaining in the core trace space. When it is applied and displaced, the separator remaining in the core trace space can be thermally deformed in a short time without decomposing or denaturing the hydrophilic organic substance. Therefore, it is possible to improve the productivity of this type of battery.

Since polyvinyl alcohol is an organic material having extremely excellent hydrophilicity, when polyvinyl alcohol is used as the hydrophilic organic material, the hydrophilicity of the separator having the hydrophilicity is improved, and the electric resistance is low. A separator having excellent electrolytic solution resistance, excellent electrolytic solution holding properties, and excellent gas permeability can be obtained, and a battery with improved charge / discharge characteristics can be obtained.

[0013] The nylon nonwoven fabric separator is
Thermoforming can be performed at a temperature of 00 ° C. or higher, and polyvinyl alcohol does not decompose or denature at a temperature of 150 ° C. or lower.
It is preferable to set the temperature to 150 ° C. or higher at a temperature higher than or equal to 150 ° C. Moreover, even if the contact time is too long even at a temperature of 150 ° C. or less, if the contact time is too long, the polyvinyl alcohol is decomposed and denatured, and the nylon is also deteriorated. It is preferable to set

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a nickel-cadmium storage battery will be described below with reference to the drawings. FIG. 1 is a perspective view showing a state in which the separator remaining in the core trace space is thermally deformed after the spiral electrode body is formed, and FIG. 2 is a view in which the spiral electrode body of FIG. FIG. 3 is a cross-sectional view showing the stored state, and FIG. 3 is a cross-sectional view showing a state where a welding electrode rod is inserted after a separator remaining in the core winding space is thermally deformed.

After a sintered porous body is formed on the surface of the punching metal 11a, a positive electrode active material mainly composed of nickel hydroxide is filled into the sintered porous body by a chemical impregnation method to produce a sintered nickel positive electrode 11. . Also, punching metal 1
After a sintered porous body is formed on the surface of 2a, a negative electrode active material mainly composed of cadmium hydroxide is filled into the sintered porous body by a chemical impregnation method to produce a sintered cadmium negative electrode 12.
On the other hand, a separator 13 is prepared by preparing a nylon non-woven fabric and applying a hydrophilic treatment to the fiber surface of the nylon non-woven fabric by applying a hydrophilic organic material, polyvinyl alcohol (PVA).
Is prepared.

Next, a core rod as shown in FIG. 4 is prepared, and the core rod is rotated about one turn with the center portion 13a of the separator 13 interposed between the slits of the core rod. 11 and a cadmium negative electrode 12 are arranged so as to be interposed between the separators 13, and the core rod is rotated to form a spiral electrode body 10 to produce a spiral electrode body 10. After this,
When the core rod is pulled out from the spirally wound electrode body 10 wound in a spiral shape, as shown in FIGS. 1 and 2, the center of the space (core trace space) S after the core rod is pulled out. The central portion 13a of the separator 13 remains so as to divide this space S into a portion.

Next, a through-hole expansion rod 20 having a tapered tip of a metal rod is prepared, and after heating this through-hole expansion rod 20 to a predetermined temperature (75 to 200 ° C.), a spiral electrode body is formed. 10 are inserted into the core trace space S. At this time, the center 13a of the separator in the core trace space S is pressed in the direction of the arrow in FIG.
For a predetermined time (1 to 4 seconds). As a result, the separator 13a remaining in the core trace space S is thermally deformed.

Here, the heating temperature of the through-hole expansion rod 20 is set to 75.
When the contact time between the through-hole expansion rod 20 and the center 13a of the separator in the core trace space S is changed from 1 to 4 seconds, the separator center 1
3a is displaced sufficiently, and the through-hole expansion rod 2 is observed.
The relationship between 0 and the contact time with the separator central portion 13a in the core trace space S, and the relationship between the heating temperature of the through-hole expansion rod 20 and the displacement of the separator central portion 13a in the core trace space S are obtained. The results were as shown in Table 1 below.

[0019]

[Table 1]

In Table 1 above, a mark 〇 indicates that the displacement was good, a mark △ indicates that the displacement was partially defective, and a mark × indicates that the displacement was defective. Table 1 above
As is clear, in order to improve the productivity, it is necessary to extend the through-hole expansion rod 20 and the separator central portion 13 in the core trace space S.
Since it is more advantageous to shorten the contact time with a, it is preferable to set the contact time to 2 seconds or less. However, when the contact time is set to 2 seconds or less, the heating temperature of the through-hole expansion rod 20 is set to 100 ° C.
Otherwise, displacement failure occurs, so 100 ° C. can be said to be the temperature at which the separator 13 can be thermoformed. After all, the contact time should be less than 2 seconds and the heating temperature should be 10
The temperature is preferably set to 0 ° C. or higher.

The spiral electrode body 1 manufactured as described above
0 is a nickel positive electrode 11 as shown in FIG.
The end of the punching metal 11a, which is the core of the electrode plate, is exposed, and the lower end of the spiral electrode body 10 is a cadmium negative electrode 1.
The end of the punching metal 12a, which is the core of the second electrode plate, is exposed. Then, the punching metal 1 of the cadmium negative electrode 12 of the spiral electrode body 10 prepared as described above is used.
2a and the negative electrode current collector 15 are resistance welded, and the end of the punched metal 11a of the nickel positive electrode 11 and the positive electrode current collector (not shown) are resistance welded.

Next, a cylindrical bottomed metal outer can 30 prepared by nickel-plated SC-size iron was prepared.
As shown in FIG. 3, this spiral electrode body 10 is
0, and one of the welding electrodes 40 is inserted into the core trace space S to be in contact with the negative electrode current collector 15 and the other welding electrode 41 is in contact with the bottom of the metal outer can 30. The negative electrode current collector 15 and the bottom of the metal outer can 30 are spot-welded. The bottom outer surface of the bottomed cylindrical metal outer can 30 serves as a negative electrode external terminal.

Thereafter, a sealing body (not shown) is prepared, and a positive electrode current collector lead extending from the positive electrode current collector is spot-welded to the bottom surface of the sealing body serving as a positive electrode external terminal.
Electrolyte solution (30% by weight potassium hydroxide (KOH) aqueous solution) is injected into each of the chambers. Then, the upper portion of the outer can 30 is bent to form a bent portion, and a sealing body having a positive electrode current collecting lead spot-welded to the bottom surface is placed on the bent portion via an insulating gasket. Of the metal outer can 3 by caulking the opening edge 31 of
The nickel-cadmium storage battery having a nominal capacity of 1.7 Ah and an SC size is assembled by closing the opening of the opening No. 0.

Here, the heating temperature of the through-hole expansion rod 20 is set to 10
When the contact time between the through-hole expansion rod 20 and the center 13a of the separator in the core trace space S is set to 2 seconds, the electrolytic solution (30 wt. % Potassium hydroxide (KOH) aqueous solution), and the time until all of the electrolytic solution is located from the upper end to the lower part of the core trace space S is measured. When the relationship with the liquid injection time was determined, the results were as shown in Table 2 below.

[0025]

[Table 2]

In Table 2 above, the symbol 〇 indicates that the injection time was 15 minutes.
Within 10 seconds, and the crosses indicate that the injection time was 15 seconds or more. As is clear from Table 2 above,
If the heating temperature of the through-hole expansion rod 20 exceeds 150 ° C., the injection time of the electrolytic solution becomes long. Therefore, the heating temperature of the through-hole expansion rod 20 is preferably set to 150 ° C. or lower.

The reason why the injection time becomes longer when the heating temperature of the through-hole expansion rod 20 becomes higher can be considered as follows. That is, the contact time between the through-hole expansion rod 20 and the center 13a of the separator in the core trace space S is set to 2 seconds, and the heating temperature is set to 1 second.
Even at 75 ° C. or 200 ° C., the nylon fibers constituting the separator 13 are not damaged by a short contact time of 2 seconds, but polyvinyl alcohol (PVA) present on the surface of the nylon fibers is decomposed, evaporated or deteriorated. It can be considered that the hydrophilicity is impaired, the permeability of the electrolyte decreases, and the injection time becomes longer.

From the above, the following holds. That is, in consideration of productivity, the contact time between the through-hole expansion rod 20 and the center 13a of the separator in the core trace space S is 2 hours.
Preferably, it is within seconds. When the contact time is within 2 seconds, the nylon 13 nonwoven fabric separator 13 can be thermoformed at a temperature of 100 ° C. or higher, and polyvinyl alcohol (PVA) decomposes, evaporates or deteriorates at a temperature of 150 ° C. or lower. Does not occur. Therefore, it is preferable that the contact time of the through-hole expansion rod 20 be within 2 seconds, and the heating temperature of the through-hole expansion rod 20 be set to 100 ° C. or more and 150 ° C. or less.

In the above-described embodiment, after the center rod 13a of the separator 13 is interposed between the slits of the core rod and the core rod is rotated about one turn, the nickel positive electrode 11 and the cadmium negative electrode 12 The spiral electrode body 10 is formed by rotating the core rod so as to interpose the core rod. However, the end of the two separators is sandwiched between the slits of the core rod, and the core rod is about The same effect can be obtained by rotating the core rod and forming the spiral electrode body by rotating the core rod so that one of the nickel positive electrode and the cadmium negative electrode is interposed between the two separators after one rotation. Occurs.

In the above-described embodiment, an example in which both the positive electrode and the negative electrode use a sintered electrode has been described. However, almost the same result can be obtained by using a non-sintered electrode such as a paste type. Was done. Further, the present invention is applicable to any battery provided with a spiral electrode body other than the nickel-cadmium storage battery.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a separator remaining in a core trace space after a spiral electrode body is formed is thermally deformed.

FIG. 2 is a view showing a cross section of a state in which the spiral electrode body of FIG. 1 is housed in a metal outer can.

FIG. 3 is a cross-sectional view showing a state where a welding electrode rod is inserted after a separator remaining in a winding core trace space is thermally deformed.

FIG. 4 is a view showing a state in which a separator is wound around a core rod, FIG. 4 (a) is a perspective view thereof, and FIG. 4 (b).
FIG. 4 is a cross-sectional view showing a state where a core rod is removed.

[Explanation of symbols]

Reference numeral 10: spiral electrode body, 11: positive electrode plate, 12: negative electrode plate, 1
DESCRIPTION OF SYMBOLS 3 ... Separator, 15 ... Negative electrode collector, 20 ... Penetration expansion rod, 30 ... Metal outer can, 31 ... Opening edge, 40, 41
… A pair of welding electrodes

Claims (3)

[Claims] 1. A winding step in which a separator is interposed between a belt-like positive and negative electrode plate, and the end or the center of the separator is wound starting from the winding core in a spiral shape with a winding core. A displacing step of displacing the remaining separator to the inner peripheral wall of the core trace space, comprising: a spirally wound electrode body; a nylon nonwoven fabric having a hydrophilic organic material on a fiber surface as the separator. Using a separator, using a through-hole expansion rod that displaces the separator end or center part to the inner peripheral wall of the core trace space, and heating the through-hole expansion rod at a temperature equal to or higher than the temperature at which the separator can be thermoformed. By adjusting the temperature to a temperature equal to or lower than the temperature at which the hydrophilic organic substance is decomposed or evaporated, the through-hole expansion rod is pressed against the separator remaining in the core trace space for a predetermined short time to displace the rod. A method for manufacturing a battery provided with a spiral electrode body. 2. The method according to claim 1, wherein the hydrophilic organic material is polyvinyl alcohol. 3. The temperature at which the separator can be thermoformed is 1
3. The spiral electrode body according to claim 1, wherein the temperature is 00 ° C., the temperature at which the hydrophilic organic substance is decomposed or evaporated is 150 ° C., and the predetermined short time is 2 seconds or less. 4. A method for manufacturing a battery comprising: