JP2870152B2 - Manufacturing method of sealing plate with insulated terminal and sealed alkaline battery using it - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a sealed alkaline battery, in particular, a peripheral edge of a metal cover plate forming a sealing plate is welded to an open end of a metal battery container to seal the battery. The present invention relates to a configuration and a manufacturing method of a small sealing plate with insulating terminals for a sealed alkaline battery, and a sealed alkaline battery using the sealing plate.

2. Description of the Related Art With the development of portable electronic devices, etc., it has excellent discharge characteristics, such as being suitable for large current discharge, or because it can be repeatedly used by a simple charging operation.
Sealed alkaline primary batteries of size AA to AA,
Alternatively, sealed alkaline batteries such as sealed alkaline storage batteries have been widely used. However, as the development of equipment has progressed, the equipment has become smaller and thinner.
High reliability is required. In response to such demands, consideration has been given to the shape of the battery and the sealing method of the battery, etc. The form is a square, square thin (rectangular) or oval tube with a side of 10 mm or less, or a 10 mm diameter. Small sealed alkaline batteries, such as the following cylindrical ones, which are easy to store in equipment have been studied, and some of them are being put to practical use. From the viewpoints of energy density and strength, these batteries house a power generation element using a metal bottomed cylindrical battery container, and are sealed using a sealing plate formed of a metal lid plate or the like. As the sealing method, a crimp-type sealing method conventionally used mainly for cylindrical batteries (a metal sealing plate having a peripheral insulating ring fitted with an annular insulating packing is placed at the opening end of the battery container, and the container opening is closed. When the edge is bent inward to seal, the processability and reliability tend to cause problems in relation to the shape and size of the battery container. Therefore, a sealing plate provided with a small insulating terminal serving as an external terminal of one electrode on a metal lid plate is placed on the opening end of the battery container, and a laser beam or the like is used.
A method of sealing the periphery of the lid plate of the sealing plate to the opening edge of the battery container by seam welding has been studied, and accurate and highly reliable welding sealing has become possible. This method is being adopted. . However, in order to obtain a highly reliable sealed state as a battery, it is necessary to secure the airtightness and the liquid leakage resistance of the insulating terminals provided on the sealing plate while reducing the size. There are roughly two types of methods for forming a miniaturized insulating terminal corresponding to the battery shape described above.
One is usually called a hermetic seal terminal described in Japanese Utility Model Publication No. 50-9530, etc., and a terminal pin is fixed to the through hole of the lid plate that constitutes the sealing plate using an inorganic insulator such as glass. Another method is to insert a rivet-shaped terminal (hereinafter referred to as a terminal rivet) into the through hole of the cover plate through an insulating packing made of synthetic resin, and tighten the leg of the terminal rivet. There is a way to fix. However, although the former is excellent in airtightness, the insulator or its sealing material is liable to be attacked by an alkaline electrolyte and has a problem of lack of reliability such as being weak against a drop impact. Usually, the latter method is mainly adopted, and a method in which the shape is examined in accordance with the form of the battery is adopted, and an example thereof will be described below.

The insulating packing interposed between the terminal rivet (or terminal pin) and the through-hole provided in the cover plate is generally divided into two or three parts, and is compressed and integrated by tightening the terminal rivet legs. Is planned. JP-A-56-107470
Japanese Patent Laid-Open Publication No. H10-21069 discloses an insulating packing (insulating resin body) having a three-part structure, that is, an example in which three annular insulating plates made of Teflon resin and having different outer diameters are stacked and used. Figure). Further, as disclosed in Japanese Utility Model Publication No. 46-21539, a rivet (eyelet terminal) having a through hole (exhaust hole) in a leg portion fixed to a sealing plate, a metal cap, and a rubber valve body As an application of the method of forming a terminal portion with an explosion-proof safety valve consisting of, in the embodiment of Japanese Utility Model Laid-Open No. 62-1369 in which a rivet is caulked and fixed via an insulating packing, an insulating packing divided into two parts is illustrated. .

FIG. 7 is a cross-sectional view of a main part of a side view showing a method of configuring insulating packing of the above-described two examples of insulating terminals. 7-1 shows a state in which an insulating terminal (the safety valve mechanism is omitted) using the latter two divided insulating packings is being assembled. The sealing plate 81 is a metal lid plate 82 having a through hole 82a.
A terminal rivet 85 having synthetic resin insulating packings 83 and 84, legs 85a, and a lead washer 86 having one polarity. I have. An annular collar portion 83a having a height h projecting from the lower surface of the lid plate through the through hole 82a of the lid plate is provided in the upper packing 83 of the insulating packing divided into two as shown in 7-2. The collar portion is inserted through the through-hole and projected to the lower surface of the lid plate.
The insulating layer is formed on the inner wall surface of the through hole 82a and the upper and lower peripheral edges thereof by fitting the lower packing 84 provided with a. Then, the upper side packing 83
As shown in the drawing, the leg portion 85a of the terminal rivet 85 is inserted into the rivet hole 83b provided therein, and a lead washer 86 is fitted at the tip thereof, and as shown in the completed assembly diagram of the sealing plate 81 in FIG. By caulking the tip of the leg 85a,
The terminal rivet 85 is fastened and fixed to the cover plate 82 to form the sealing plate 81 with the insulating terminal 87. FIG. 7-3 is a sectional side view showing a configuration of the former three-part divided insulating packing. In a case where this is applied to a sealing plate 81 of 7-1 as an example, three ring-shaped insulating packings are shown. holes for inserting the rivet legs 85a are provided on the insulating plate 93, 94, and 95, the outer diameter phi ₁ and a thickness t of the intermediate insulating plate 94, the inner diameter and the thickness of the through hole 82a of the cover plate 82 Fit into the through hole as matching dimensions,
After the insulating plates 93 and 95 are provided on the lower surface, the rivet legs 85a are passed through the holes of the three insulating plates, and the ends of the rivet legs are caulked and fixed in the same manner as in FIG. 8 via washers. , Insulating terminals are formed.

Since a sealed battery using an alkaline electrolyte is liable to cause leakage of the electrolyte (see below), in order to maintain leakage resistance as used in a cylindrical battery,
It is necessary to interpose a sealing agent having good adhesion (alkaline batteries usually have asphalt or tar pitch as a main component) between the insulating packing and the lid plate (see below). In the case of the above-mentioned two-part insulating packing, Japanese Utility Model Application Laid-Open No. 62-1369 describes that a packing having a surface coated with a sealant is used. Specifically, as shown at 7-1 in FIG. 7, at least portions of the insulating packings 83 and 84, which are in contact with the upper and lower surfaces of the cover plate 82, before being assembled, are coated with the sealing agent such as the asphalt to form a seal. The film 87 was formed and used.

As described in Japanese Utility Model Publication No. 37-164 and Japanese Examined Patent Publication No. 46-15254, the leakage of the electrolyte from the sealed portion of the alkaline battery is described as follows. And has the property that the sealing piece is wetted out of the sealed portion of the battery by the wetting and capillary action. This phenomenon appears strongly on the metal surface connected to the negative electrode, that is, on the negative electrode terminal side of the sealing portion, and liquid leakage easily occurs. This is generally known as a liquid leakage phenomenon due to electric capillary action. As described above, a small sealed alkaline battery to which the present invention is applied is sealed by welding a metal cover plate to a metal battery container with a laser beam or the like, but generally the battery container is a negative electrode. Since it is designed so as to also serve as a terminal, the electrolyte solution easily leaks from the portion where the cover plate and the insulating packing come into a negative potential in a normal battery use state as described above. For these reasons, in the case of an alkaline battery, sufficient leakage resistance cannot be obtained only by mechanically tightening the insulating packing, and many proposals using a sealant have been studied. As a result,
As described in JP-B-37-119, JP-B-46-15254, etc., a material having electrolytic resistance and being softer than the material of the insulating packing and having good adhesion to the packing and the metal surface is selected. , Asphalt, tar pitch, tar / epoxy resin, etc., or a mixture thereof, or a sealant containing an oily substance, an olefinic compound, a rust inhibitor, etc., is generally used to improve the leakage resistance of sealed alkaline batteries. The effect is shown (there is also a case of using a thermoplastic and alkali-resistant synthetic paint or adhesive such as a vinyl-based or acrylic-based resin, but the improvement effect was lower than the above-mentioned one).

Problems to be Solved by the Invention In the configuration of the sealing plate with insulating terminals used in such a conventional sealed alkaline battery, the number of parts increases, the assembly process becomes complicated, and the sealing plate for a small battery is used. If applied, the accuracy of the forming process of the divided insulating packing will affect the assembly workability of the sealing plate and the sealing performance of the terminal part, and a large factor that may cause poor assembly of the sealing plate or decrease the liquid leakage resistance of the terminal part. And other issues.

For example, when the two-part packing shown in FIGS. 7-1 and 7-2 is used, the through-hole 82a (inner diameter φ) of the cover plate and the annular collar portion 83a (outer diameter φ ₁ ) of the upper packing are used. Further, the fitting accuracy when the collar insertion hole 84a (inner diameter φ ₂ ) of the lower packing and the annular collar portion are fitted to each other greatly affects the assembled state of the sealing plate 81 as described above. . That is, if the respective fitting gaps are small or negative, the fitting cannot be performed in the assembly process. Alternatively, each packing is often deformed, resulting in defective assembly, poor sealing or poor insulation, and is usually designed to provide a slight gap. 83,84 insulating packing, 8 through holes in the lid plate
2a, rivet leg 85a (outer diameter), etc. If the machining accuracy of each part is improved and each fitting gap is pressed down to about 0.02 to 0.05mm, the tip of rivet leg 85a will be caulked and tightened properly. The effect of the sealant is obtained within the range of caulking pressure,
Although it is possible to stabilize the leakage resistance of the terminal portion, in the case of a miniaturized sealing plate, there is a problem that the assembling work becomes difficult and the productivity is reduced. Further, in order to secure the above-described fitting accuracy when mass-producing each of the above components using a plurality of dies, high accuracy is required for die processing and maintenance, which makes management difficult. In particular, nylon 6, which is generally used as an insulating packing for sealed alkaline batteries,
When a resin such as nylon 66 (trademark, polyamide resin), which has a large dimensional change due to moisture absorption, is used, dimensional changes are likely to occur due to environmental changes (humidity, temperature), and it is difficult to secure the above-described fitting accuracy. there were. In such a case, usually, the fitting tolerance range of each fitting portion is 0.05
It was manufactured and operated with a target of about 0.2 mm, and the caulking operation had to be performed in small lot units while increasing or decreasing the caulking pressure applied to the tip of the rivet leg 85a. However, even with such a method, defective assembly such as deformation and damage due to misalignment of the upper and lower insulating packings or insufficient airtightness of the insulating terminal portion is likely to occur at the time of assembling, and as shown in FIG. In addition, gaps G1 and G2 remain around the insulating packing of the terminal after the assembly is completed, reducing the liquid leakage resistance or crimping the rivet legs due to excessive crimping force and warping the cover plate 82. Therefore, when the cover plate is welded to the opening end of the battery container, there is a problem that a welding failure occurs.

In order to eliminate such a trouble in fitting in the sealing plate assembling process, the present inventors did not divide the above-mentioned insulating packing, but through the through-hole 82a of the lid plate and the through-hole inner wall surface and the lid plate 82. We tried to apply the method of integrally forming the upper and lower surfaces by a resin molding method usually called insert molding method, but even with this method, the adhesion between the synthetic resin constituting the insulating packing and the metal surface of the lid plate was It was insufficient, and it was not possible to prevent leakage of the alkaline electrolyte at this portion by the electric capillary action. Therefore, in order to ensure the leakage resistance of the terminal portion, the combined use of the above-mentioned sealant is an essential condition, and in the above-described method, the sealant is covered with the sealant in a step before forming the insulating packing on the upper and lower surfaces of the cover plate. It must be applied to the board surface. However, according to the study results of the present inventors, a lid plate coated with a sealant is loaded into a resin molding die, and a resin heated and melted as an insulating packing component is injected under pressure into the die (as described above). With nylon 66 etc.
When the melting temperature is 270 to 300 ° C and the injection pressure is 500 to 1000 kg / cm ² ), the sealing agent on the lid plate and the surface thereof is rapidly heated to almost the same temperature as the molten resin, and the above-mentioned conventional sealing agent is used. In this case, it was found that at this point, the heat-damaged material lost its function as a sealant, and also deteriorated the physical properties of the formed insulating packing. That is, as a sealant applied to the inner peripheral edge of the through-hole (82a in FIG. 7) and the upper and lower surfaces of the lid plate around the through-hole, the above-mentioned asphalt, tar pitch or the like alone or as a main component If a conventional sealant such as a paint or a vinyl paint is applied, the heat resistance is low, so if it comes into contact with the above-mentioned molten resin, the sealant coating film (thin layer) will be formed within a molding time of several tens of seconds. ) Melts or softens and peels off the lid plate,
In the vicinity of the through hole where the inflow gap is small, the inflow speed of the molten resin injected at a high pressure is increased, so that the sealant flows out and is diffused or mixed into the resin as a film. However, it has been a factor of deterioration of physical properties such as deterioration of strength of insulating packing. For these reasons, it has been difficult to put the method of forming the insulating packing integrally using the above-mentioned sealant together into practical use.

As another measure for preventing liquid leakage in a method in which the insulating packing is formed integrally with the lid plate, as shown in FIG. 2 of Japanese Utility Model Laid-Open No. 61-119256 or Japanese Utility Model Laid-Open No. 60-3553, FIG. An annular rising portion is provided on the periphery of the through hole of the cover plate toward the upper surface or the lower surface side of the cover plate (refer to FIG. 6, described later), or Japanese Utility Model Publication No. 36-26438 or Japanese Utility Model Publication No. 63-26438.
As described in Japanese Patent No. -106059, by providing an annular acute projection (not shown) on the back surface of the head of the rivet, the rising portion of the through hole or the acute projection is attached to the insulating packing when assembling the sealing plate. There is a plan to improve the airtightness of this part by digging into it. The present inventors have studied applying this idea to the above-described method of integrally forming the insulating packing. As an example, the sixth
The figure shows a case where a rising portion is provided in the through hole. In the figure, a sealing plate 71 is provided with a lid plate 72 provided with a rising portion 72b upward at the periphery of a through hole 72a, an insulating packing 74 integrally formed on the upper and lower surfaces of the lid plate, a terminal rivet 85, a washer 86.
When the rivet leg portion 85a is caulked and fastened, the rising portion 72b is made to bite into the insulating packing to improve the sealing performance at this portion.
However, when the insulating packing is formed by the insert molding method, since the molten resin flows along the shape of the rising portion and is molded, the rising portion cannot be digged in. There were few. Also,
Both the method of providing the rising portion and the method of providing the acute angle projection on the rivet head are formed by press working during mass production, so that it is difficult to obtain a uniform annular projection, and the above-described electrical capillary action unique to the alkaline electrolyte. It was not enough to prevent liquid leakage. These methods were rather effective when the sealant 87 was used in combination with the divided insulating packing as shown in FIG. As described above, the improvement measures for integrally forming the insulating packing with the lid plate have problems in the sealant and processing.

The present invention solves this problem by providing an insulating seal layer having excellent heat resistance and adhesiveness on the periphery of a through hole of a lid plate, and then integrally insulating the upper and lower surfaces of the substrate. A new method of manufacturing a sealing plate with insulating terminals that simplifies the assembly process and stably improves workability by configuring insulating terminals by using the one with the packing formed, and airtightness and leakage resistance using the sealing plates. It is an object of the present invention to provide a sealed alkaline battery having excellent liquid properties.

Means for Solving the Problems The present invention, in order to achieve the above object, a metal lid plate provided with a through-hole, on the upper and lower surfaces surrounding the periphery of the through-hole or any one surface and the inner wall surface of the through-hole, An insulating seal layer is formed using an insulating sealant made of a composite mainly composed of a fluororesin and a binder having heat resistance and electrolyte resistance, and then the upper and lower surfaces of the lid plate including the surface of the insulating seal layer and After integrally forming an insulating packing layer made of a synthetic resin having leg insertion holes for terminal rivets on the inner wall surface of the through hole by injection molding or the like,
The terminal rivet leg is inserted into the leg insertion hole, and the tip is fastened and fixed with an appropriate pressing force to form a sealing plate with insulating terminals.

As described above, the present invention also provides an insulating seal layer formed mainly of a fluororesin and a binder around the perimeter of the through hole of the lid plate, and then integrally forms an insulating packing on the upper and lower surfaces of the lid plate and the inner wall surface of the through hole. A layer is formed, and a terminal rivet is inserted into the insulating packing layer, and the terminal rivet is inserted and fastened and fixed. The periphery of the plate is welded to the open end of the battery container,
A sealed alkaline battery is formed by sealing.

According to the above method, the insulating sealing layer provided in advance on the lid plate can withstand the pressure injection of the molten resin during the molding of the packing resin, so that the insulating packing layer is integrally formed on the upper and lower surfaces of the lid plate by injection molding or the like. In addition, the problem of the above is solved, and by eliminating the fitting gap generated in the insulating seal layer and the insulating packing portion, it is possible to produce an insulated terminal having a stable airtightness and a conventional method of manufacturing a sealing plate with an insulated terminal. The process is simplified as compared with, and the production becomes easy.

Also, by using the sealing plate by this method,
In the process of welding the edge of the lid plate to the opening end of the battery container, it is possible to suppress the occurrence of poor welding due to the deformation of the lid plate, and the insulating seal layer is made water-repellent by the synergistic effect of the main component fluororesin and the binder. , Heat resistance, improvement of electrolyte resistance and flexibility, adhesion to the metal surface of the cover plate is ensured, and wetting of the metal surface around the through hole of the cover plate by the electrolyte is suppressed. In addition, the sealed alkaline battery provided with a sealing plate with an insulating terminal excellent in liquid leakage resistance can be prevented from leaking out of the electrolytic solution due to the electric capillary action, and in combination with the stabilization of the airtightness of the insulating terminal portion. can get.

As described above, the present invention relates to a sealing plate with an insulating terminal applied to a small square (including a square thin shape and a rectangular shape), an oval shape and a small-diameter cylindrical battery, and a sealing plate using the same. The present invention is directed to a shape-type alkaline battery. Here, a rectangular battery and a sealing plate thereof will be described as an example with reference to the drawings.

<1> Manufacturing Method of Sealing Plate Each of the drawings shown in FIGS. 1-1 to 1-5 shows a side cross section of one side of the sealing plate.
2 is a diagram illustrating an assembling process of the sealing plate with insulating terminals of FIG.

Example 1 In FIG. 1, 1-1-2 indicates a rectangular / metallic cover plate constituting a sealing plate, which is formed by pressing a nickel-plated steel plate or a stainless steel plate into a dish with a flat peripheral edge by pressing. Thus, a through hole 2a for fixing an insulating terminal (described later) is provided at the center. Next, as shown in 1-2, a fluororesin powder and a heat-resistant and alkali-resistant electrolytic solution binder are applied to the upper and lower surfaces surrounding the periphery of the through hole 2a of the lid plate 2 and the inner wall surface 2b of the through hole. As a main component, an insulating sealant dispersed in a solvent and prepared in a liquid or paste form is applied, dried, and heated (described later in detail) to form an insulating seal layer 3. When the use condition of the battery to which this sealing plate is applied is to be used for a long time in an environment including high temperature and high humidity, as in the example of the above-mentioned 1-2, the insulating sealing layer 3 is formed on the periphery of the through hole of the lid plate. It is desirable to form on the upper and lower surfaces surrounding. However, if the operating environment conditions of the battery are relatively mild, a practically sufficient effect can be obtained even if the formation range of the insulating sealing layer 3 is set to only one of the peripheries of the through hole of the lid plate.

Next, a resin molding die (not shown) having a cavity of a predetermined shape to which an insert molding method (common name; for example, a method of integrally molding a resin cover around a metal shaft) is applied. After the lid plate 2 provided with the insulating seal layer 3 is loaded, the polyamide resin (nylon 66) melted by setting the cylinder temperature of the injection molding machine equipped with the mold to 290 to 300 ° C. is injected. 700-1000k
g / cm ² , with a molding cycle of 20 to 30 seconds, and pressurized and molded into the mold, and as shown in 1-3, the upper surface 4a of the lid plate 2 including the surface of the insulating seal layer 3 , The lower wall 4b and the inner wall surface 4c of the through hole 2a excluding the rivet leg insertion hole 4d,
An insulating packing layer 4 is formed.

Subsequently, as shown in 1-4, the rivet leg 5a of the terminal rivet 5 molded using nickel-plated steel or the like is inserted into the rivet leg insertion hole 4d provided in the insulating packing layer 4.
(At this time, the inner peripheral edge of the insertion hole 4d, the rivet leg 5a
If necessary, a conventional sealing agent such as asphalt is applied to the outer periphery of the insulating packing 4) and inserted as shown by the arrow A in the drawing to protrude from the lower surface of the insulating packing 4, and a rivet hole 7a is formed at the protruding tip. The provided lead washer 7 for connecting the positive electrode lead is fitted as shown by the arrow B in the drawing, and then the tip of the rivet leg 5a is caulked using a crimping die so that the cover plate 2 is not deformed such as warpage. Depending on the applied pressure,
By crimping as shown by arrow C in FIG. 5, the terminal rivet 5 is fastened and fixed to the insulating packing layer 4 and the cover plate 2 to form the insulating terminal 6 and the sealing plate 1 with the insulating terminal is obtained.

Next, a method for forming the insulating seal layer 3 will be described. First, an example in which the above-mentioned liquid or paste-like insulating sealant is used will be described.

The insulating sealant is a one-part or two-part thermosetting resin (uncured) such as a fluororesin powder and an epoxy resin as a binder. The main component is the one with the addition of a thermoplastic resin, and the one with a small amount of a dispersed filler added as necessary.
A liquid or a paste prepared by adding an appropriate amount of a solvent in accordance with the application method is used. In the above, as the fluororesin, polytetrafluoroethylene resin (PTF
E), ethylene tetrafluoride / propylene hexafluoride copolymer resin (FEP) and ethylene tetrafluoride / perfluoroalkyl vinyl ether copolymer resin (PFA) are applicable (Note;
These fluororesins alone have a weak binding force to a metal surface and cannot be used as a sealant), the melting temperature of the resin forming the insulating packing is high (about 270 ° C or higher), or the water repellency of the insulating seal layer is large. In this case, it is preferable to use a tetrafluoroethylene resin. Approximately 30 μm
The following powders are used, but those having a particle size of about 0.5 to 10 μm are preferable from the viewpoint of coating properties and water repellency. As described above, when the insulating packing is formed by injection molding or the like, the insulating seal layer 2 is heated by contacting with the hot-melt resin as described above, but one molding cycle (typically within 10 to 60 seconds) ), It is necessary to prevent the insulating seal layer 3 from melting and diffusing (into the resin) or peeling. In the insulating seal layer 3 of the present invention, the combined use of the fluororesin powder improves the heat resistance and the electrolyte resistance (mainly the alkali resistance) of the binder as compared with the case where the binder is used alone, but the selection is an important factor. Becomes From such a viewpoint, in order to secure the adhesive force (adhesive strength) when heated, an alkali-resistant thermosetting resin (for example, epoxy resin, a modified resin thereof, or a composite with another resin) is used as a binder. Object) is mainly used. As for the case where an epoxy resin is used as the binder, bisphenol A type epoxy, novolak type epoxy, cycloaliphatic epoxy and the like can be used as the resin component, but in terms of preparation of sealant, coating workability, etc. Bisphenol A type is easy to use.
In addition, in order to obtain a material having good heat resistance and adhesiveness, the combination with a curing agent should be performed at a curing temperature of 120 ° C. or higher, preferably about 150 ° C.
It is preferable to use one having a temperature of 200 ° C. In order to improve the kneading workability and coating property of the main agent, a small amount of a dispersion auxiliary filler such as alumina, calcium carbonate, calcium silicate or the like may be added as needed (about 15% by weight or less of the total of the main agent). Next, the above specific example will be described.

Example 1A Using a one-pack type epoxy resin as a binder,
Hexamethylenetetramine, imidazole derivatives, dicyandiamide, and the like are added in advance as a latent curing agent, and the curing reaction is performed by heating, so that the coating workability is good.

An appropriate amount of a solvent such as toluene, xylene, or methyl isobutyl ketone was added to the above mixture, and the mixture was kneaded to prepare a paste-like (low-viscosity) insulating sealant. This is applied to a predetermined surface of the periphery of the through hole 2a of the cover plate 2 by a method such as stamping or roll transfer and dried to form a coating film having a thickness of about 30 μm, and then placed in a heating furnace at 170 to 200 ° C. For 5 to 30 minutes to cure the epoxy resin and form the insulating seal layer 3. Although the obtained insulating seal layer 3 achieves its purpose as it is, it is further baked in a firing furnace at 280 to 300 ° C. for 2 to 5 minutes, whereby the fluororesin powder layer on the surface of the insulating seal layer is sintered, It is desirable to add this baking step because the water repellency and the oxidation resistance excellent in the period can be imparted (the same applies to the examples described later). The cover plate 2 provided with the insulating seal layer 3 of the embodiment to which the baking step is added is provided with polypropylene used as an insulating packing material,
Using a resin material such as polyamide, polyacetal (copolymer), and changing the cylinder temperature to 240-320 ° C,
When an insulating packing was formed and assembled as a sealing plate, no abnormality occurred in the insulating sealing layer.

Example 1B An example is shown in which a two-pack type epoxy resin is used as a binder. As the curing agent, a high-temperature curing type such as an acid anhydride or an aromatic polyamine is used, and a curing treatment is performed at 150 to 180 ° C. The compounding is performed according to the compounding table of the solid component in Example 1A. If the fluororesin powder is divided into the resin and the curing agent and then kneaded, it is easy to mix uniformly during the two-liquid mixing. For the viscosity adjustment, the above-mentioned solvent is used,
If the addition amount is large, a reactive diluent (low molecular weight epoxy compound) such as diglycidyl ether can be used as a solid component during the curing reaction, which causes troubles such as air bubbles during coating and drying. Effective for reduction. Further, if a plurality of resin-based composites are used as the resin component instead of the epoxy alone as described above, the heat resistance or the adhesion can be further improved. For example, a compound such as epoxy and bismaleimide can be used for resin molding at an injection molding temperature higher than that of the above example without lowering the adhesion.

Example 1C A high-melting-point, alkali-resistant thermoplastic resin such as polyethersulfone (PES) or polyetheramide powder was mixed with the above-mentioned thermosetting resin such as the epoxy resin or a composite thereof as a binder. The total compounding amount is the equivalent amount of the epoxy resin in the solid composition table of Example 1A, and the ratio between the thermosetting resin and the thermoplastic resin is 1: 0.2 to 1 (parts by weight). ). When the thermoplastic resin is used in combination as described above, when the firing step shown in Example 1A is performed, the adhesive strength between the fluororesin and the lid plate is increased, and an insulating seal layer having good adhesion can be formed. .

Example 2 In the method of manufacturing the sealing plate of Example 1 described with reference to FIG. 1, an example in which an ultraviolet-curable epoxy resin is used as a binder of the insulating sealant forming the 1-2 insulating seal layer 3 will be described. Show. Bisphenol A diglycidyl ether to which an ultraviolet cationic initiator (for example, an allyldiazonium salt of complex halide) is added, or epoxy acrylate obtained by reacting acrylic acid with bisphenol epoxy is used as a one-part epoxy resin of Example 1A. If used in place of resin, an insulating sealant is applied to the lid plate (after drying if a solvent is included), and cured in about 10 to 30 seconds by irradiating ultraviolet rays through various UV lamp tunnels Can be performed. When the use environment conditions of the battery to be applied are relatively mild, the object of the insulating seal layer can be achieved even with only the above-described curing treatment, so that by applying this method, the processing time can be shortened and continuous processing by mechanization can be achieved. Processing becomes possible.

Example 3 In the process of the sealing plate manufacturing method shown in FIG. 1, the method of forming the insulating sealing layer 3 was changed to the method of applying the liquid insulating sealing agent shown in 1-2 (see Example 1), As shown in FIG. 2A-1, the sheet-shaped insulating sealant is formed into a predetermined thin film ring-shaped insulating sealant piece 31 having a hole 31a corresponding to the through hole 2a of the lid plate, After being stacked so as to surround the periphery of the through hole 2a of the cover plate 2 and pressurized in the stacking direction as shown by the arrow D in the drawing, or while being pressurized by using a hot press mold, it is heated to 180 to 200 ° C. The insulating sealant piece 31 is cured and brought into close contact with the lid plate, and as shown in 2A-2 and 2B, the insulating seal layer 3 is formed on one or both sides of the lid plate. The insulating sealant piece 31 is made of a high viscosity bisphenol A or cycloaliphatic epoxy resin as shown in the above-described embodiment, or a combination of a semi-solid epoxy resin and a latent curing agent as a binder. The mixture is kneaded with a fluororesin powder, a filler, etc., kneaded, and then formed into a seal by extrusion or the like, and then into a thin film ring of a predetermined shape by punching or the like, as described above. Before the treatment, a slight tackiness is generated by pressurization, so that it can be easily temporarily adhered to a predetermined surface of the lid plate 2. According to the method described above, the insulating seal layer 3 having a uniform thickness can be easily formed even on a narrow surface.

Embodiment 4 FIG. 4 shows a side cross section of another embodiment of the present invention having a different terminal configuration, that is, a sealing plate 101 with an explosion-proof insulated terminal provided with a safety valve at a terminal portion. Example 1
(Assembling process diagram of the sealing plate in FIG. 1)
After providing an insulating film sealing layer 3 on a predetermined surface of the periphery of the through hole 2a of the cover plate 2, and then forming an insulating packing layer 4 having rivet leg insertion holes 4d, as shown in FIG. Terminal rivet 5 with hollow rivet legs 51a provided
1, a rivet leg 51a is inserted into the rivet leg insertion hole 4d (see FIG. 1) and protrudes from the lower surface of the insulating packing layer 4, and a lead washer 7 for connecting a positive electrode lead is provided as shown in FIG. After the fitting, as described above, the tip of the rivet leg 51a is tightened and fixed by caulking. Next, an elastic valve body 53 made of synthetic rubber or the like is always closed in an empty room formed by the head of the terminal rivet 51 provided with the valve port 51b and the metal cap terminal 52. In this manner, the cap collar 52a is fixed to the terminal rivet head by welding or the like to form a return-type safety valve, and is mainly applied to a sealed-diameter alkaline storage battery. In addition, as an explosion-proof device, a non-return type, in which a thin portion is provided in a part of the cover plate (not shown) in the example of FIG. 1 and the thin portion is torn and exhausted when the pressure in the battery becomes excessive, is used. It may be a thing.

Embodiment 5 FIGS. 1-6 and 1-7 in FIG. 1 show one example of an assembling process of a sealing plate 11 of another example in which the shape of the insulating packing layer is partially different from that of the embodiment 1. FIG. That is, an L-shaped lead plate 17 having a rivet hole 17a and a long tip is used for connection with the electrode plate group, insulation between the lead plate and the battery container, and the electrode plate group and the cover plate 2 are provided. This shows an example of a case where an insulating pedestal 15 is separately provided to prevent a short circuit of the electrode plate group by being interposed therebetween. 1-
As shown in FIG. 6, the insulating packing layer 14 has a shorter extension length on the lower surface side 14b of the cover plate 2, but as shown in 1-7, the rivet leg 5a is caulked and fastened. In this case, the sealing effect mainly occurs in the portion corresponding to the corners of the upper and lower surfaces of the inner peripheral edge of the through hole 2a of the cover plate 2. Therefore, if the length of the lower surface side 14b is as shown in the drawing, and if there is a length corresponding to the vicinity of the tip of the caulked portion of the rivet leg 5a, airtightness can be ensured, so that the same leak-proofing as in the first embodiment. A liquid effect can be obtained.

<2> Embodiment of Battery FIG. 3 shows a cross section of a main part of one side of one embodiment of a sealed rectangular alkaline battery sealed with a sealing plate with insulating terminals obtained by the method of the present invention. It is a thing. 8
Is a bottomed, square cylindrical battery container made of nickel-plated steel, in which a positive electrode active material powder such as manganese dioxide, silver oxide, etc. is coated using a mesh or a porous sheet of nickel or the like as a base material. After coating the plate, and zinc oxide powder, a zinc negative electrode plate that has been porous metallized by electrolytic reduction or the like, a plurality of sheets are alternately stacked via a separator such as a polyamide nonwoven fabric or a polyolefin microporous sheet,
An electrode group of an alkaline primary battery impregnated with a predetermined amount of an alkali zincate electrolyte, or a nickel porous substrate, was charged with nickel hydroxide as a positive electrode active material and cadmium hydroxide as a negative electrode active material, and subjected to a chemical conversion treatment. A positive electrode plate and a negative electrode plate or a negative electrode plate filled with a hydrogen storage alloy powder are combined, stacked as described above via a separator, and an alkaline storage battery electrode group impregnated with an alkaline electrolyte is generated. It is housed as element 9 and its negative electrode lead is connected to battery case 8. As the sealing plate 1 with insulating terminals for sealing the battery container 8, the sealing plate shown in Example 1 of the manufacturing method of the sealing plate is used. That is, in FIG. 3, reference numeral 2 denotes a cover plate made of nickel-plated steel, and as shown in FIG.
The insulating seal layer 3 mainly composed of the fluororesin powder and the one-pack type epoxy resin (binder) described in the above Example 1A is formed on the periphery of. Insulating packing layers integrally formed on the upper and lower surfaces of the cover plate, 5 is a terminal rivet made of nickel-plated steel, 7 is a lead washer made of a thin nickel plate, and is formed by caulking a rivet leg 5a of the terminal rivet. ,
As shown, cover plate 2, insulating seal layer 3, insulating packing layer 4,
The terminal rivets 5 are integrally fastened to form an insulating terminal 6. After welding the positive electrode lead 9a of the power generating element 9 to the tip of the lead washer 7 of the sealing plate,
The sealing plate 1 is fitted into the opening end of the battery container 8, and the joint between the peripheral edge of the lid plate 2 and the opening end of the battery container 8 is irradiated with a laser beam to perform seam welding, thereby forming a welded portion 10 to form a battery. The container was sealed. In the above, the sealed alkaline storage battery is often required to have an explosion-proof function. In that case, instead of the sealing plate 1 shown in FIG. 3, the explosion-proof insulating terminal of the fourth embodiment shown in FIG. It can be similarly sealed using the sealing plate 101.

In the present invention, as described in the above embodiment, a composite mainly composed of a fluororesin (powder) and a heat-resistant and electrolyte-resistant binder is used as the insulating sealant. For measures to improve the water repellency, separately use an insulating seal layer made of fluororesin alone using a binder that does not contain a binder, such as an aqueous dispersion in which fluororesin is dispersed in water with a small amount of a surfactant. Although a method of forming the same (Reference Example 1) was also examined, there were problems in the sealing plate assembling step and the physical properties of the sealing layer, which were insufficient. That is, a thin layer formed from an aqueous dispersion is 200
In the case of drying by heating at about ℃ or less, the water repellency is insufficient because a large amount of surfactant remains, and it is necessary to bake at about 300 to 360 ° C for several tens minutes to remove the surfactant. ,
Problems such as surface oxidation and thermal deformation of the cover plate are likely to occur. In addition, the formed sealing layer, including the fired one, has a high melting point (327 ° C. for PTFE), but begins to soften at a relatively low temperature (from about 200 ° C.), and has a surface of nickel or its nickel. Adhesion with a cover plate made of a thin metal plate such as an alloy or stainless steel is small, and when the insulating packing layer 4 is formed by injection molding, the insulating packing layer 4 is lifted or peeled off from the cover plate surface under the influence of heating and flow pressure. The sealing layer and the cover plate become incompletely adhered due to the occurrence or partial pressurization when the terminal rivet 5 is caulked and fastened. However, there is a problem that it is difficult to stably prevent it. In addition, in the case of a thin layer of a fluororesin alone, PTFE and the like tend to cause many pinholes and the effect of the seal layer tends to decrease.

Next, a description will be given of the state of occurrence of assembly failure and assembly workability when a sealing plate with insulating terminals is manufactured by the above-described manufacturing method of the present invention and the method of the conventional example.
The components such as the lid plate and the terminal rivet which constitute the sealing plate are of the same specifications, and the upper surface of the lid plate shown in 5-2 in FIG. 5 (upper side perspective view) is rectangular (short side S). , Long side L, and the example shown in FIGS. 3 and 1 corresponds to the short side cross section)
In order to apply to the prismatic battery of (5), use a nickel-plated steel plate with a short shape like 5-1-2, (S) 7 mm × (L) 15 mm, thickness 0.4 mm, and the terminal rivet 5 2mm diameter
Was used. As for the manufacturing method and structure, the method of the first embodiment (the method of forming the insulating seal layer 3 is the same as that of the embodiment 1A) is applied to the present invention, and the conventional example is shown in FIG.
As shown in 1,7-2, put the insulating packing up and down
A method of dividing and separately molding and using the same was applied, and a seal paint mainly composed of bron asphalt was applied as a seal film 87 (FIG. 7-1). As a result of producing 10,000 pieces each once and repeating this five times, in the conventional example, the upper and lower insulating packings 83 and 84 are incorporated into the cover plate.
Alternatively, when the legs of the terminal rivet are inserted into the insulating packing, defects such as deformation of the insulating packing caused by misalignment occur at an average of 3.5%, and the cover plate in the terminal rivet caulking step is tightened. In the long side direction (see L in FIG. 5A), warpage deformation failure occurs on average 0.3%, and other process defects such as missing lead washers are 0.03%.
In total, more than 3.8% of assembly failures occurred. On the other hand, the defect in the assembling process according to the manufacturing method of the present invention is as follows.
%, A total of 0.048%, which was reduced to about 1/80 of that of the conventional example. Further, according to the manufacturing method of the present invention, the manufacturing cost (man-hours) of the sealing plate can be reduced by about 20% compared to the conventional example because the process is simplified as compared with the conventional method. did it. Next, using the sealing plate with the insulating film terminal of the present invention and the conventional example manufactured as described above, and the sealing plate of the reference example (see below) manufactured by another measure different from the manufacturing method of the present invention as described above, A square sealed alkaline storage battery containing the alkaline storage battery electrode group was constructed. Next, these batteries were subjected to a liquid leakage test at an insulating terminal portion using an environmental test tank. The test batteries were sealed using the following six types of sealing plates for comparison. No. 1 is according to the present invention described above, and No. 2 is according to Reference Example 1 described in the description of the embodiment, and a fluorine resin aqueous dispersion was used in place of the insulating sealant used in the present invention, Painted on board,
After drying, heat treatment is performed at about 290 ° C. for 5 minutes to form the insulating seal layer 3. No. 3 is obtained by omitting the insulating sealing layer 3 when manufacturing the sealing plate of the present invention (Reference Example 2). As described above, a rising portion is provided on the periphery of the through hole of the lid plate (Reference Example 3). No. 5 is the above-mentioned conventional example, and No. 6 is the sealing plate configuration of the conventional example of No. 5, except that the sealing film 87 shown in 7-1 is omitted (reference example of the conventional example). . Each of the sealing plates was assembled by applying the same sealing agent as that applied to the insulating packing of the No. 5 conventional sealing plate to the outer periphery of the leg portion of the terminal rivet, followed by drying. The environmental test was performed under the following two conditions.

A. Heat cycle test The above 24h is repeated as one cycle.

B. High-temperature and high-humidity storage test Leave in a test tank at 70 ° C and 90-95% humidity.

The test was started in a fully charged state with 300 test batteries each. After that, supplementary charging was performed every 10 to 15 days, and the test was continued.
Table 1 shows the results of the test (the rate of liquid leakage from the insulating terminal portion).

As shown in the liquid leakage rate in Table 1, No. 1 according to the present invention is No. 5 of the conventional sealing plate, that is, a blown asphalt-based sealing film as described above on the surface of the insulating packing divided into two parts. It can be seen that it has the same or higher resistance to liquid leakage as compared with the one formed with. In addition, in order to improve the sealing property of the insulating terminal portion, the insulating sealing layer is provided as described above. However, this is omitted. Reference Example 2 of No. 3, Reference Example 3 of No. 4,
From the comparison with No. 5 and No. 6 in the conventional example, it can be seen that there is an effect equal to or more than that of the seal film used in the conventional example. In addition, comparison with the result of Reference Example 1 of No. 2 in which the insulating seal layer was formed of the fluororesin alone shows the importance of the method of forming the insulating seal layer. Note that the insulating seal layer 3 in the present invention must be made of a material having sufficient insulating properties. The reason is that the above-described insulating seal layer 3 is provided as a means for imparting electrical insulation and water repellency to the metal surface around the through hole 2a of the lid plate.
The surface of the perimeter of the through hole is also prevented from swelling (creep) by the electrolytic solution due to the electric capillary action, thereby preventing leakage of the electrolytic solution from the contact surface between the cover plate 2 and the insulating packing layer 4. This is because, when the insulating property of the insulating seal layer is reduced, the above-described suppression effect is reduced. As described above, the present invention in which the insulating seal layer is closely adhered to the periphery of the through hole,
Compared to a conventional example in which a sealing film is provided on the surface of an insulating packing, even in a mass-produced product, the effect of suppressing liquid wetting at the periphery of the through hole can be stably obtained. This was also confirmed from the results of disassembly observation of the insulated terminal portion of the liquid leak test product (product No. 1 of the present invention, No. 5 of the prior art) shown in Table 1 after the test was completed.

In the present invention, as described above, the insulating seal layer 3 is provided using an insulating sealant composed of a composite mainly composed of a fluororesin and a binder having heat resistance and electrolytic solution resistance (alkali resistance). In order to solve the problem in the insulated terminal assembling process of the method of fitting and using the insulating molding of the split molding described as the conventional example, a hot-melted resin such as injection molding is used as a method of configuring the insulating packing. hand,
This is to cope with a decrease in the leakage resistance of the insulating terminal portion which occurs when the method of integrally molding the upper and lower surfaces of the cover plate 2 is employed. It has been found that the composite has a large synergistic effect, such as high adhesive strength, heat-resistant adhesive strength, resistance to electrolytic solution, and water repellency. Although partially shown in the above liquid leakage test results, when the above-mentioned fluororesin or the binder is used alone, when the insulating packing layer is molded, or when the insulated terminal assembly is deteriorated, It cannot be applied because of insufficient liquid leakage resistance.

In addition, the same improvement effect was obtained in the other examples which were not shown in the results of assembling the sealing plate and the results of the battery leakage test according to the above example.

Effect of the Invention As described above, according to the present invention, after providing an insulating seal layer of a composite mainly composed of a fluororesin and a binder on the periphery of the through hole of the cover plate, including the periphery of the through hole of the cover plate By manufacturing a sealing plate with insulating terminals by using an insulating packing layer integrally formed on the upper and lower surfaces, there is no deterioration of the insulating sealing layer due to heating during resin molding, The fact that no gap is formed between the insulating packing layer and the insulating packing layer makes it possible to easily produce a sealing plate having good airtightness of the insulating terminal portion and stable quality. Further, according to the manufacturing method of the present invention, since the deformation of the cover plate is eliminated, welding with the opening end of the electrical terminal container can be reliably and easily performed, and
A sealed alkaline battery having excellent airtightness and liquid leakage resistance can be obtained.

[Brief description of the drawings]

1, 2, 3, 4 and 5 show an embodiment of the present invention, and FIGS. 1-1 to 1-5 show steps of assembling a sealing plate with insulating terminals of the present invention. 1 is a sectional side view of one side of a sealing plate, FIGS. 1-6 and 1-7 are side sectional views showing another embodiment, and FIG. 2 is a side sectional view showing an insulating seal layer provided by another embodiment. FIG. 3 is a fragmentary sectional view of a rectangular sealed alkaline battery sealed with a sealing plate with insulating terminals according to the method of the present invention. FIG. 4 is a side sectional view showing a sealing plate with explosion-proof insulating terminals according to the present invention. Fig. 5 is a perspective view of the appearance of the test battery for liquid leakage test and the lid plate used for the same, Fig. 6 is a sectional side view of the sealing plate for comparative study, and Figs. It is a sectional side view which shows the structure of the attached sealing plate and divided insulating packing. 1,11: sealing plate with insulating terminals, 2: lid plate, 2a: through hole, 3: insulating sealing layer, 31, insulating sealing agent piece, 4, 14
... Insulating packing layer, 4d, 14d ... Rivet leg insertion hole, 5, 51 ... Terminal rivet, 5a, 51a ... Rivet leg,
51b …… Valve, 52 …… Cap terminal, 53 …… Valve, 6,16,
61 ... Insulated terminal, 7 ... Lead washer, 17 ... Lead plate, 8 ... Battery container, 9 ... Power generation element, 10 ... Welded part, 101 ... Sealing plate with explosion-proof insulating terminal.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Hamada 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-52-145731 (JP, A) JP-A-55-55 100651 (JP, A) JP-A-64-642 (JP, A) JP-A-49-6137 (JP, U) JP-A-2-36163 (JP, U) JP-A-60-174057 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) H01M 2/04-2/08 H01M 2/30

Claims (4)

(57) [Claims] 1. A fluororesin and a heat-resistant / electrolyte-resistant solution are provided on both upper and lower surfaces or any one surface of the metal cover plate 2 provided with the through-hole 2a and surrounding the periphery of the through-hole 2a and on the inner wall surface of the through-hole 2a. An insulating seal layer 3 mainly made of a binder having a property is provided. Then, the upper and lower surfaces of the cover plate 2 including the surface of the insulating seal layer 3 and the inner wall surface of the through hole 2a are integrally formed of synthetic resin or the like. The insulating packing layer 4 is formed by an insert molding method, and the insulating packing layer 4 is inserted into a rivet leg insertion hole 4d.
Then, terminal rivets 5 are inserted into the rivet leg insertion holes 4d.
A method for producing a sealing plate with an insulating terminal for a sealed alkaline storage battery in which an insulating terminal 6 is formed, wherein the rivet leg 5a is inserted and the tip of the leg 5a is fastened and fixed. 2. A liquid or paste-like insulating sealant prepared by dispersing in a solvent using a fluororesin powder and a binder mainly composed of an uncured thermosetting resin as a main component,
It is applied on a predetermined surface surrounding the periphery of the through hole 2a of the lid plate 2 and dried, and then the lid plate coated with the insulating sealing agent is heated to cure the thermosetting resin in the binder. The method for producing a sealing plate with insulating terminals for a sealed alkaline storage battery according to claim 1, wherein the insulating sealing layer 3 is formed. 3. An insulating sealant piece 31 formed into a thin film ring shape using a binder made of a powder of a fluororesin and an uncured thermosetting resin as a main component, and a peripheral portion of the through hole 2a of the lid plate 2. 2. The insulating sealing layer 3 is formed by stacking on a predetermined surface surrounding the insulating sealing agent piece, and then heating the insulating sealing agent piece 31 while pressing or pressing the insulating sealing agent piece 31 in the stacking direction. Of sealing plates with insulating terminals for sealed alkaline storage batteries. 4. A metal battery container 8 containing a power generating element 9.
And a sealing plate 1 with an insulating terminal. The sealing plate 1 has a metal cover plate 2 provided with a through hole 2 a and an insulating terminal 6, and the periphery of the cover plate 2 is The insulating terminal 6 seals the battery container welded to the open end. The insulating terminal 6 includes a terminal rivet 5 having a rivet leg 5a, an insulating packing layer 4 having a rivet leg insertion hole 4b, and an insulating seal. The rivet terminal 5 has a rivet leg 5a inserted into the rivet leg insertion hole 4d and is fixedly fastened. The insulating packing layer 4 is provided with an insulating seal layer 3. The upper and lower surfaces of the cover plate and the inner wall surface of the through hole 2a are integrally formed by an insert molding method. The insulating seal layer 3 mainly includes a fluororesin and a binder around the periphery of the through hole 2a of the cover plate. Sealed alkaline battery formed by an insulating sealant.