JP3568356B2 - Method of manufacturing prismatic battery and prismatic battery - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention includes a method for manufacturing a prismatic battery, relates prismatic battery with a built-in electrode plates.
[0002]
[Prior art]
The pore size of the sponge-like porous metal body can be freely changed from 100 μm to several mm. For this reason, for various electrode active materials such as nickel hydroxide powder and hydrogen storage alloy powder, it is possible to select an optimal pore size according to the characteristics of each active material and use it as an electrode. It has good physical properties, and thus has preferable physical properties as a battery electrode plate.
[0003]
The sponge-like porous metal body is manufactured by plating a sponge-like organic porous body, that is, a plastic foam, removing the organic porous body by roasting, and then sintering. A technique for manufacturing an electrode plate by this method is described in, for example, JP-A-4-303564. The method described in this publication produces an electrode plate in the following steps.
[0004]
(1) A sponge-like organic porous material such as urethane foam is immersed in a plating tank and plated after pre-treatment. In this plating step, the organic porous material is plated by being immersed in a plating tank under tension in a certain direction. The organic porous body plated in this state is in a state where the holes are elongated in the tension direction.
[0005]
(2) The plated organic porous body is roasted in the air. After roasting, the resin component constituting the organic porous material is removed. When the resin component is removed, a plated portion remains.
[0006]
(3) The plated portion from which the resin component has been removed is sintered to form a porous metal body. Since the porous metal body is formed by plating a metal on the inner surface of the porous fine pores of the sponge-like organic porous body and sintering the metal, the porous state becomes a porous state similar to the organic porous body.
[0007]
(4) The metal porous body is cut into a rectangle. The cutting direction is such that the tension direction during the plating process is the long side direction of the electrode plate. In other words, the electrode plate is manufactured such that the long side direction of the electrode plate becomes the tension direction of the plating process.
[0008]
[Problems to be solved by the invention]
The electrode plate manufactured in the above steps is manufactured by applying tension in the direction shown by the arrow in FIG. 1 in the step of plating the organic porous body, so that the holes 2 of the metal porous body 1 are Thus, the electrode plate 3 has a shape elongated in the long side direction. The porous metal body 1 produced by stretching and plating in this direction has a disadvantage that cracks and cracks occur in the direction indicated by the chain line in the figure and the strength is reduced. This is because a long gap is formed in the direction indicated by the arrow. The reduction in the strength of the porous metal body 1 reduces the yield during battery assembly.
[0009]
In particular, in the case of a prismatic battery, when the strength in the long side direction of the electrode plate is reduced as compared with a battery in which the positive and negative electrodes are spirally wound and inserted into a cylindrical outer can, the yield in the step of inserting the outer can is reduced. descend. The battery in which the positive and negative electrode plates are spirally wound and inserted into the cylindrical outer can can be inserted into the outer can while protecting the inner electrode plate in a pressed state with the outer electrode plate. However, in the case of a prismatic battery in which positive and negative electrode plates are simply laminated and inserted into an outer can, the outer electrode plate protects the inner electrode plate in a pressed state and cannot be inserted into the outer can. For this reason, when inserting into an exterior can, a force is applied to the electrode plate in the insertion direction, that is, in the long side direction of the electrode plate. For this reason, an electrode plate having insufficient strength in the long side direction lowers the yield in the step of inserting it into the outer can. In particular, the strength of the long-side direction is not sufficient, prone plate of cracks and cracks in the direction indicated by the chain line in FIG. 3, when inserted into the outer can, as shown in the enlarged cross-sectional view of FIG. 2 In addition, the electrode plate 3 breaks through the separator 4 and causes an internal short circuit. When the porous metal body 1 is damaged by cracks or cracks and is pushed into the outer can in the direction indicated by arrow A, the surface of the electrode plate 3 locally projects, and the separator 4 Break through and cause an internal short circuit. Since the separator 4 is extremely thin, even if the porous metal body 1 is damaged in an extremely fine region, it breaks through the separator 4 and causes an internal short circuit.
[0010]
Further, as shown in FIG. 3, the electrode plate of the prismatic battery is connected to the electrode lead 5 at one end on the long side and inserted into the outer can. If the electrode plate 3 to which the electrode lead 5 is connected is cracked in the direction indicated by the chain line, the electric resistance between the electrode lead 5 and the tip of the electrode plate 3 increases, or the tip of the electrode plate 3 is connected to the electrode lead. 5, the electrical capacity of the electrode plate 3 is reduced, and the battery performance is reduced.
[0011]
Further, the above disadvantages become more remarkable as the amount of active material filled in the porous metal body 1 of the electrode plate 3 is increased to increase the battery capacity. This is because the porosity of the porous metal body 1 increases, and the strength of the porous metal body 1 decreases. For this reason, there is a disadvantage that the higher the capacity is, the more serious the above-mentioned adverse effects are, and the higher the capacity of the battery is, the lower the yield is.
[0012]
The present invention has been developed to solve such disadvantages. An important object of the present invention is to provide a plate that can be designed large, the prismatic battery that can be inserted into prismatic outer can with a high yield, a prismatic battery using this electrode plate.
[0013]
[Means for Solving the Problems]
Method for manufacturing a prismatic batteries according to claim 1 of the present invention, the organic porous body such as urethane foam, a first step of plating treatment while applying a tension in a predetermined direction, the organic porous material is heated subsequent to the step A second step of removing the porous metal body 1 to prepare it; a third step of filling the porous metal body 1 with an active material; and inserting the porous metal body 1 filled with the active material into the outer can 6 of the prismatic battery. A fourth step of cutting into a possible rectangular shape, and a step of inserting the electrode group 7 in which the rectangular electrode plates 3 are laminated in a state where the electrode plates provided on both sides are in electrical contact with the inner surface of the rectangular outer can 6. .
[0014]
Furthermore, the manufacturing method of rectangular batteries of the present invention, in the first step of plating treatment, the tension direction of the organic porous material, characterized by a short side direction of the rectangular plate 3. The electrode plate 3 manufactured by applying tension to the organic porous body and plating it in the direction indicated by the arrow A in FIG. 4 can increase the strength in the direction indicated by the arrow B. The direction indicated by the arrow B is a direction in which the electrode plate 3 is inserted into the rectangular outer can 6. For this reason, the electrode plate 3 strong in this direction can be inserted into the rectangular outer can 6 with a high yield.
[0015]
In the prismatic battery according to the second aspect of the present invention, the organic porous body that has been plated while being pulled in a certain direction is roasted in the air to form a porous metal body 1. The electrode plate 3 cut into a rectangular shape that can be inserted into the outer can 6 of a prismatic battery is inserted into the outer can 6. This prismatic battery is manufactured by plating a metal porous body 1 by pulling an organic porous body in a short side direction of a rectangular electrode plate 3. Further, the electrode group 7 in which the rectangular electrode plates 3 are stacked is inserted into the outer can 6 in a state where the electrode plates disposed on both sides are in electrical contact with the inner surface of the rectangular outer can 6.
[0016]
Further, in the prismatic battery according to claim 3 of the present invention, the direction of the tension when plating the organic porous body is specified, and the average inner diameter of the porous hole 2 of the porous metal body 1 constituting the electrode plate 3 is determined. Are longer in the short side direction than in the long side direction of the electrode plate 3. Also in this prismatic battery, the electrode group 7 in which the rectangular electrode plates 3 are stacked is inserted into the outer can 6 in a state where the electrode plates provided on both sides are in electrical contact with the inner surface of the rectangular outer can 6.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following examples illustrate a manufacturing method and a prismatic battery for embodying the technical idea of the present invention, and the present invention does not specify the manufacturing method and the prismatic battery below.
[0018]
Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments are referred to as "claims" and "means for solving the problem". Are added to the members indicated by "." However, the members described in the claims are not limited to the members of the embodiments.
[0019]
The prismatic battery shown in FIG. 5 is a prismatic alkaline storage battery. This prismatic alkaline storage battery is a nickel-hydrogen storage battery, in which an electrode group 7 is housed in a prismatic outer can 6. The electrode group 7 is obtained by laminating a positive electrode plate 3A and a negative electrode plate 3B with a separator 4 interposed therebetween. In the electrode group 7, the negative electrode plates 3 </ b> B provided on both sides are electrically contacted with the inner surface of the rectangular outer can 6. The positive electrode plate 3A of the electrode group 7 is connected to the positive electrode terminal 9 of the sealing lid 8 insulated and fixed to the outer can 6 via the electrode lead 5. The positive electrode terminal 9 of the sealing lid 8 has a built-in safety valve.
[0020]
The rectangular outer can 6 is made of iron, and its surface is plated with nickel. However, it goes without saying that the outer can is not limited to iron and may be made of, for example, stainless steel.
[0021]
A prismatic battery, which is a nickel-hydrogen storage battery, is manufactured by inserting an electrode group 7 into an outer can 6, injecting an electrolytic solution, and laser welding a sealing lid 8 to an opening of the outer can 6. The positive electrode plate and the negative electrode plate are manufactured as described below.
[0022]
A. Manufacture of positive electrode plate
(1) A porous metal body is prepared in the following steps.
After pretreatment, the sponge-like organic porous body, which is an open-celled polyurethane foam, is immersed in a plating solution in an electrolytic cell and plated in a state where tension is applied in a certain direction, that is, in a slightly stretched state. The tension for pulling the organic porous body is set to an optimum value in consideration of the thickness and width of the organic porous body. For example, an organic porous body having a thickness of about 2 mm and a width of 500 mm is plated while being pulled by a tension that makes the ratio of the major axis / minor axis of the porous hole of the metallic porous body about 1.3. The plated organic porous body is roasted at a temperature of 750 ° C. for a predetermined time to remove the resin component of the organic porous body, and then sintered in a reducing atmosphere to produce a metal porous body. In the sponge-like porous metal body manufactured in this step, the mechanical strength is higher in a direction perpendicular to the stretching direction than in a direction parallel to the stretching direction.
[0023]
(2) The following are kneaded to form an active material paste.
Nickel hydroxide powder 90 parts by weight (containing 2.5 wt% of zinc and 1 wt% of cobalt as a coprecipitating component)
Cobalt powder 7 parts by weight of zinc oxide powder 3 parts by weight Part 0.2% by weight aqueous solution of hydroxypropylcellulose 50 parts by weight
(3) The prepared active material paste was filled in the voids of the porous metal body, dried, pressed to adjust the thickness, cut into a rectangle having a discharge capacity of 600 mAh, and then cut into short sides as shown in FIG. Is electrically connected to the electrode lead 5. The rectangular positive electrode plate is cut into a shape in which the direction in which the organic porous material is pulled during the plating treatment is the short side direction of the rectangle. In other words, the tension direction in which the organic porous body is pulled during the plating process is set to the short side direction of the positive electrode plate cut into a rectangle. In the positive electrode plate manufactured in this step, the average inner diameter of the porous hole 2 of the sponge-like metal porous body 1 is larger than that of the long side direction of the electrode plate 3 as shown in an enlarged view of a main part of FIG. It is longer in the short side direction.
[0025]
B Production of negative electrode plate
(1) Preparation of hydrogen storage alloy, crushed misch metal (a mixture of rare earth elements such as La, Ce, Nd, Pr), cobalt, aluminum, and manganese are weighed to a predetermined weight and mixed. It is put in a crucible, melted in a high-frequency melting furnace and then cooled to produce a hydrogen storage alloy electrode having the following composition formula.
MmNi3.4Co0.8Al0.2Mn0.6
Then, the obtained ingot of the hydrogen storage alloy is pulverized in an inert gas so that the average particle size becomes 150 μm.
[0026]
(2) Preparation of hydrogen storage alloy paste Polyethylene oxide powder as a binder is added to the pulverized hydrogen storage alloy powder, and ion-exchanged water is further added and kneaded to form a paste slurry. The added amount of the polyethylene oxide powder as the binder is 0.5% by weight based on the hydrogen storage alloy.
[0027]
(3) A slurry of the hydrogen storage alloy is applied to the current collector and dried.The obtained slurry is coated on both sides of a current collector made of punched metal to a predetermined thickness, applied, and then dried. Press and adjust the thickness. Then, it is cut to a predetermined size to obtain a negative electrode plate. Note that a sponge-like porous metal material, a nickel fiber mat, or the like can be used as the current collector. In this case, the current collector is filled with an active material paste and manufactured.
[0028]
Next, as shown in FIG. 5, a separator 4 is interposed between the positive electrode plate 3A and the negative electrode plate 3B for insulation, and these are laminated to form an electrode group 7. A nonwoven fabric made of polypropylene having a thickness of 0.2 mm is used for the separator 4. The electrode group 7 has a discharge capacity of 600 mAh. The electrode group 7 is inserted into the rectangular outer can 6, 1.25 g of an electrolyte is injected, and the opening of the outer can 6 is closed with the sealing lid 8. As the electrolyte, a 7 to 8.5 N KOH aqueous solution containing LiOH and NaOH is used.
[0029]
【The invention's effect】
The prismatic battery manufacturing method and prismatic battery according to the present invention have a feature that an electrode plate that can be designed to have a large capacity by increasing the filling amount of an active material can be inserted into a prismatic outer can at a high yield. This is because the strength of the porous metal body of the electrode plate manufactured by the method of the present invention in the long side direction of the rectangle is increased and the porous metal body can be reliably inserted into the outer can. The porous metal body having sufficient strength in the long side direction of the rectangle can be inserted into the outer can of the prismatic battery at a high yield. This is because, unlike the conventional electrode plate, as shown in FIG. 2, cracks or cracks generated locally in the electrode plate do not break through the separator and cause an internal short circuit. Further, when the electrode plate having sufficient strength in the long side direction is pushed into the outer can of the prismatic battery, the electrode plate is surely inserted into the outer can without deformation such as deformation. In particular, the porosity of the organic porous material is increased, and the electrode plate in which a large amount of the outer can is filled in the void tends to have a reduced strength.However, the electrode plate manufactured by the method of the present invention has It has the strength that it can be inserted securely into a small outer can.
[Brief description of the drawings]
FIG. 1 is a partially enlarged front view of an electrode plate used in a conventional prismatic battery. FIG. 2 is an enlarged sectional view showing a state in which the electrode plate shown in FIG. 1 is inserted into an outer can. FIG. FIG. 4 is a partially enlarged front view of an electrode plate used in a prismatic battery according to an embodiment of the present invention. FIG. 5 is a partial cross-sectional perspective view of a prismatic battery according to an embodiment of the present invention. [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Metal porous body 2 ... Hole 3 ... Electrode plate 3A ... Positive electrode plate 3B ... Negative electrode plate 4 ... Separator 5 ... Electrode lead 6 ... Outer can 7 ... Electrode group 8 ... Sealing lid 9 ... Positive electrode terminal

Claims (3)

A first step of plating while applying tension to the organic porous body in a certain direction, and a second step of heating and removing the organic porous body to produce a porous metal body (1) following this step; a third step of filling an active material into the body (1), filled porous metal body of active material (1), cut into rectangles can be inserted into the outer can (6) of the prismatic battery, a rectangular plate ( a fourth step of a 3), a rectangular plate (3) laminated electrode group (7), the electrode plate arranged on both sides on the inner surface of the prismatic outer can (6) in a state electrically contacting in manufacturing method of prismatic battery comprising a step of inserting,
A method for manufacturing a prismatic battery, wherein in the first step of plating, the tension direction of the organic porous material is set to the short side direction of the rectangular electrode plate (3) . The organic porous material that has been plated while being pulled in a certain direction is roasted in air to form a porous metal material (1), and the porous material of the porous metal material (1) is filled with an active material. Then, in a rectangular battery obtained by inserting an outer can (6) into a rectangular plate that can be inserted into an outer can (6) of a prismatic battery (3),
Electrode metal porous body (1) is Ri Na is manufactured by plating process by pulling the organic porous body in the short side direction of the rectangular plate (3), and, by laminating the plates (3) of the rectangular A prismatic battery wherein the group (7) is inserted into the outer can (6) in a state where the electrode plates provided on both sides are in electrical contact with the inner surface of the rectangular outer can (6) . The organic porous material that has been plated while being pulled in a certain direction is roasted in air to form a porous metal material (1), and the porous material of the porous metal material (1) is filled with an active material. Then, in a prismatic battery obtained by inserting an electrode plate (3) cut into a rectangular shape that can be inserted into an outer can (6) of a prismatic battery into an outer can (6),
Average inner diameter of the porous pores of the porous metallic body forming the electrode plate (3) (1) (2), the electrode plate (3) Ri greens by increasing the short-side direction than the longitudinal direction of, and said rectangular plate (3) laminated electrode group is (7), in a state in which electrical contact with the inner surface of the plate to be arranged on both sides prismatic outer can (6) to the outer can (6) A prismatic battery characterized by being inserted .

Images