JP2005166620A - Electrode plate for storage battery and open type alkaline storage battery using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent peeling and falling off of an active material from the end part of an electrode plate in which a paste-like active material is filled and coated on a porous sheet. <P>SOLUTION: In coating the end part consisting of the surface periphery and edge of an electrode plate formed by filling and coating paste-like active material on a porous sheet 2 and cut in a desired shape, by an adhesive such as a hot-melt adhesive or a resin, the edge side is coated thicker than the electrode plate surface side of the periphery part, thereby, peeling or falling off of the active material can be prevented, and the life of the storage battery using this can be improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a storage battery electrode plate obtained by filling a porous sheet with an active material and an open-type alkaline storage battery using the same.

  An electrode plate for a storage battery, for example, an electrode plate for a nickel / cadmium alkaline storage battery, is used by filling a metal porous sheet such as nickel with a paste-like active material and cutting it into a desired size. At this time, in order to prevent a short circuit due to metallic burrs at the end of the electrode plate, particularly at the cut end, it is known to coat the end with a resin or the like (Patent Document 1).

JP-A-5-190200

  However, like the paste-type cadmium negative electrode plate used in nickel-cadmium alkaline storage batteries, the electrode plate, which has a structure in which a porous active material is simply coated and filled with a porous sheet, has a low strength, and the active material from the porous sheet is reduced. Because it is easy to peel off and drop off, the electrode plate with adhesive or resin applied and fixed does not cause much problem with sealed storage batteries that generate less gas from the negative electrode during normal use, but when used for open storage batteries, Since relatively intense gas generation occurs from the negative electrode plate at the end of charging, the active material peels off or falls off from the porous sheet during use.

  In order to solve the above-mentioned problems, the present inventor has intensively studied, and as a result, the resin thickness covered by these coated electrode plates is the same at the end portion, that is, the end plate side and the electrode plate surface side which is the electrode edge. Focusing on the coating, the problem is solved by thickly applying the end surface side, which is a cut surface, to the electrode plate surface side when the adhesive or resin is applied and fixed.

  According to the present invention, it is possible to prevent the active material from peeling off or dropping off from the electrode plate by applying an adhesive or resin thicker on the end surface side with respect to the electrode plate surface side, thereby improving the durability of the electrode plate. In this way, the battery life can be improved.

  In the present invention, a long porous sheet such as a nickel punching sheet is coated and filled with a paste-like active material, and after this is formed or cut into an electrode plate of a desired size without being formed, it is bonded to the end. Agent and resin are applied and fixed, and the end face is thickly applied to the surface of the electrode plate. As a method, the end of the electrode plate of the desired size is dipped in an adhesive or melted resin, and then pulled up so that a large amount of adhesive or resin is clumped at the end of the electrode plate. Adhere to. After that, the adhesive or resin adhered does not solidify, and excess adhesive and resin are removed through the slit. At that time, the edge of the electrode plate, that is, the slit on the electrode surface side is narrow, and the end side is wide. By doing so, it is possible to apply the coating thickness thicker at the end side with respect to the electrode plate surface side, and then the applied adhesive or resin is dried and solidified. The coated electrode plate is shown in FIG. 1 is an application part such as an adhesive, 2 is a porous sheet, 3 is an active material filled and applied on both sides of the porous sheet, a is a coating thickness on the electrode plate surface side, b is a coating thickness on the electrode plate end surface side, c represents the coating width on the electrode plate surface side.

  A hot melt adhesive mainly composed of polypropylene is applied to the end of the paste type cadmium negative electrode plate cut to a predetermined size, and the coating thicknesses on the electrode plate surface side are 0.01 mm, 0.05 mm and 0.10 mm, respectively. The cut end face side coating thickness was applied to 0.5 mm. And the coating width of the electrode plate surface side was applied to 0.5 mm, 1 mm, 3 mm, 5 mm and 7 mm, and a negative electrode plate of a to g shown in Table 1 was prepared, and each of the prepared negative electrode plates was sintered. An open nickel-cadmium alkaline storage battery was fabricated in combination with a nickel positive electrode plate. These storage batteries were designated as A to G, respectively.

Comparative example

  Next, as a comparative example, a hot melt adhesive mainly composed of polypropylene is similarly applied to the end portion of the paste type cadmium negative electrode plate, and is applied to the thickness of 0.5 mm only on the cut end surface without applying it to the electrode plate surface side. The same coating thickness of 0.05 mm each on the electrode plate surface side and the cut end surface side, the electrode plate surface side application width of 1 mm, and the electrode plate surface side and the cut end surface side at all Three types of those that were not applied were prepared. They are shown in Table 1 as h to j. Each of the produced negative electrode plates was combined with a sintered nickel positive electrode plate to produce an open nickel / cadmium alkaline storage battery in the same manner as in the above example. These storage batteries were designated H to J, respectively.

  Each paste-type cadmium negative electrode plate produced in the above-mentioned Examples and Comparative Examples was charged to −1.65 V (vs. nickel plate) using a nickel plate as a counter electrode in an aqueous KOH solution at an environmental temperature of 25 ° C. , Charging / discharging until 1.5 V (vs. nickel plate) was repeated 50 times, and the presence or absence of peeling or dropping of the active material was observed. The results and the number of drops are shown in Table 1.

  As is clear from Table 1, the negative electrode plates a, b, c, d, f and g, which are the products of the present invention, were charged and discharged 50 times, but did not drop off. Moreover, although the negative electrode plate e which is the product of the present invention dropped off after 45 times, it was better than the comparative product, and the effect of preventing peeling and dropping was improved.

  Next, an electrode plate group obtained by laminating each paste type cadmium negative electrode plate prepared in Examples and Comparative Examples via a sintered nickel positive electrode plate and a separator is housed in a battery case, and an open nickel cadmium having a nominal capacity of 40 Ah. An alkaline storage battery was produced, and the number of times until each battery was reached at the environmental temperature of 25 ° C. until it was charged and discharged at a discharge depth of 60% was measured. The charge / discharge was performed at a current of 0.25 CA, the charge amount was 1.4 times the discharge amount, the life was when it was reduced to 60% of the rated capacity, and the capacity was confirmed every 50 times. The results are shown in Table 2.

  As is apparent from Table 2, all of the products of the present invention obtained good results, and in particular, those having an application width of 1 mm or more on the electrode plate surface side excluding the battery E were many times and had a long life.

  Furthermore, each storage battery was prepared using a negative electrode plate with various coating widths on the electrode plate surface side, and this was sustained when charged at 0.1 CA for 15 hours and discharged to 1 V at 1 CA at an environmental temperature of 25 ° C. The time was measured, and the capacity retention rate for the storage battery to which no adhesive was applied was determined. The results are shown in FIG.

  The capacity retention rate decreased as the coating width on the electrode plate surface side increased. The reason for this is thought to be that the application width is reduced because the reaction area between the active material and the electrolytic solution is reduced due to the wide application width. From this result, the electrode plate surface side coating width is preferably 5 mm or less.

  Furthermore, as a result of various experiments, the coating thickness on the end face side is preferably 0.1 mm or more, and increasing the coating thickness on the electrode surface side increases the dimension in the thickness direction of the electrode plate group formed by laminating the electrode plates. Therefore, the thickness is preferably 0.01 to 0.05 mm.

Partial view of electrode plate for storage battery applied to end The figure which shows the application | coating width | variety and capacity | capacitance maintenance factor of an electrode plate surface side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Application | coating part 2 Porous sheet 3 Active material a Electrode surface side application thickness b Electrode end surface side application thickness c Electrode surface side application width

Claims (4)

  In an electrode plate for a storage battery in which an adhesive or resin is applied and fixed to an end portion of an electrode plate obtained by filling and applying an active material to a porous sheet, the electrode plate at the end portion of the electrode plate is coated with the adhesive or resin to be applied and fixed. An electrode plate for a storage battery, wherein the end face side is thicker than the front side.   2. The electrode plate for a storage battery according to claim 1, wherein the thickness of the adhesive or resin applied and fixed is 0.01 mm 0.05 mm on the electrode plate surface side and 0.1 mm on the end surface side.   3. The electrode plate for a storage battery according to claim 1, wherein the coating width on the surface side of the electrode plate to which the adhesive or resin is applied and fixed is set to 1 mm to 5 mm.   An open-type alkaline storage battery using the storage battery electrode plate according to claim 1.

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