JP2005071964A - Alkaline accumulator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrict the generation of an internal short circuit in an alkaline accumulator in which a substrate exposing portion composed of a three-dimensional porous material is provided on one of long side edges of a rectangular electrode plate formed by providing an active material on a metallic substrate composed of three-dimensional porous material, the substrate exposing portion projects at the edge of a group of electrode plates and a current collection terminal is connected to the edge of the substrate. <P>SOLUTION: A rectangular substrate non-compressed portion 3 having one side which is a long side of the rectangle is provided on an exposing portion of a substrate composed of three-dimensional porous material, and a belt-shaped substrate compressed portion 4 is provided between the substrate non-compressed portion and the boundary of an active material non-filled portion and an active material filled portion 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an alkaline storage battery suitable for large current discharge used as a power source for an electric tool, an electric bicycle, a hybrid electric vehicle (HEV) or the like.

  A sealed alkaline storage battery using a negative electrode mainly composed of a hydrogen storage alloy has been expanded in use from the viewpoint of having excellent charge / discharge characteristics and excellent environmental conservation. Among them, attention has been paid as a power source for electric tools and electric bicycles and a power source for HEV power, and a great demand is expected. These applications generally require a large output. Therefore, a battery applied to the above-described use is required to have excellent high rate discharge characteristics.

  The positive electrode plate and the negative electrode plate used in these batteries are made thin to make the working area of the electrode plate as large as possible. Specifically, a rectangular positive electrode plate and a negative electrode plate having a reduced thickness and an increased working area are stacked with a separator interposed therebetween, and the stacked body is swirled as shown in FIG. Or a stacked electrode plate group shown in FIG. 5 in which a plurality of positive and negative electrode plates are alternately stacked with a separator interposed therebetween.

  As the structure of the electrode plate group, a structure generally called a tabless system is adopted. In the wound electrode plate group shown in FIG. 3, one long side end portion 18 of the positive electrode plate protrudes from one wound end surface (upper side, 11B in the drawing) of the electrode plate group 11. The positive electrode plate (not shown because it is hidden) is obtained by supporting an active material mainly composed of nickel hydroxide on a three-dimensional porous substrate such as nickel foam. The end portion 18 of the positive electrode plate is not filled with an active material and the substrate is exposed (this portion is referred to as an active material non-filled region or a substrate exposed region, but is hereinafter referred to as a substrate exposed region). . A disc-shaped positive current collecting terminal 22 is joined to the end face of the substrate at the exposed portion of the substrate. The joining is usually joined by resistance welding. A positive electrode lead side 23 for connecting the current collector terminal and a positive electrode terminal (not shown) is joined to the upper surface of the positive electrode current collector terminal 22.

One long side end portion 17 of the negative electrode plate 11 protrudes from the other winding end surface (lower side, 11A in the figure) of the electrode plate group. The negative electrode plate 12 is obtained by supporting an active material such as a hydrogen storage alloy or cadmium on a three-dimensional porous body such as a perforated steel sheet having a large number of holes formed in a nickel plated steel sheet or foamed nickel. The end portion of the negative electrode plate 11 is not filled with an active material and the substrate is exposed (this portion is hereinafter referred to as a substrate exposed region). A disc-shaped negative electrode current collecting terminal 20 is bonded to the end face of the substrate at the exposed portion of the substrate. This joining is usually joined by resistance welding. The negative electrode current collecting terminal 20 is joined to a metal battery case (not shown) that also serves as a negative electrode terminal.
In addition to the simple donut-shaped metal disk shown in 22 of FIG. 3 and FIG. 4A, the current collector terminals of the positive electrode and the negative electrode, and 22 shown in FIG. A protruding piece {20A in FIG. 3; 26 in FIG. 4 (B)} is provided for assisting welding of the substrate end face of the negative electrode plate, or a notch {in FIG. 4 (B) is used to reduce reactive current during welding. 25} can also be provided.

  As shown in FIG. 5, in the laminated electrode plate group 31, one long side end portion 32 of the positive electrode plate (not shown because it is hidden) protrudes from one laminated end surface (on the left side in the drawing), The long side end portion 34 of one of the negative electrode plates 33 is protruded on the opposite end face of the laminate (the right hand back side in the figure). As in the case of the wound-type electrode plate group, the protruding long-side end portion 32 of the positive electrode and the long-side end portion 34 of the negative electrode plate are both substrate exposed regions, and each substrate end face is made of a rectangular nickel plate. The positive current collecting terminal 36 and the negative current collecting terminal 37 are joined. The joint is usually joined by resistance welding as in the case of the wound electrode group. In the figure, reference numeral 35 denotes a separator inserted between the positive electrode plate and the negative electrode plate.

  The most widely used method of joining the current collecting terminal and the end face of the substrate is joining by series spot welding. Taking the case where the positive electrode current collector terminal 22 is bonded to the substrate of the positive electrode plate as an example, the positive electrode current collector terminal 22 is placed on the end surface of the substrate exposed portion 3 of the positive electrode plate 1 as shown in FIG. The terminal 41 of the welding machine is brought into contact with the upper surface of the current collecting terminal 22. Then, the current collector terminal 22 is pressed against the end surface of the substrate so that the current collector terminal 22 is in close contact with the end surface of the substrate exposed portion 3, and a welding current is applied to join the two. FIG. 6 is a diagram schematically showing a cross section of the positive electrode plate 1. The positive electrode plate is an active material filling region 2 in which a substrate made of foamed nickel is filled with an active material and a substrate exposed on one long side of the positive electrode plate. It consists of region 3. Since the substrate exposed region 3 is soft, it is deformed in the process of joining the current collecting terminals 22 as shown in FIG. 7, and the deformed portion penetrates the separator 13 or the active material falls off due to the deformation. There was a possibility that the active material mass penetrating the separator 13 might cause a short circuit in the electrode plate group. In addition, 12 of FIG. 7 shows a negative electrode plate.

  In the process of bringing the current collecting terminal plate into close contact with the end surface of the substrate, a pressing force is applied to the end surface of the substrate. Since the porous substrate is inherently soft, when the pressing force is applied, the active material unfilled portion of the substrate is deformed and swells in the thickness direction of the electrode plate, and the thickness of the substrate of the active material unfilled portion becomes the thickness of the electrode plate. It is not uncommon to exceed. In addition, the deformation of the substrate may cause the active material filling portion in contact with the active material non-filling portion and dropping of the active material. As described above, when the thickness of the substrate exceeds the thickness of the electrode plate or the active material falls off, a part of the metal porous body or the lump of the active material constituting the substrate penetrates the separator to cause an internal short circuit. There was a risk of it happening.

In order to eliminate the fear, a method has been proposed in which the substrate is compressed by applying a force in the same direction as the pressing force applied to the end portion of the substrate in advance to increase the mechanical strength of the compressed portion of the substrate. (See Patent Document 1)
However, in this method, when the substrate end portion is compressed, pressure is applied to the active material filling portion and the substrate exposed portion and the active material filling portion. However, there is a drawback that the thickness of the substrate increases at the boundary between the thickness of the substrate and the thickness of the substrate becomes larger than the thickness of the electrode plate, and the active material cannot be prevented from falling off.

In order to compensate for the lack of hardness of the substrate in the active material non-filled portion, as shown in FIG. 8, the active material non-filled portion (substrate exposed portion) 3 provided in a rectangular shape at the long side end of the electrode plate. Is compressed in the thickness direction of the electrode plate, and a metal foil hoop 5 having a width substantially equal to that of the non-filled portion of the active material and having a thickness of 0.1 to 0.5 mm is bonded to the compressed substrate. An electrode plate configuration has been proposed. (See Patent Document 2)
JP, 56-86459, A (page 3, Example 3) However, in order to make this electrode plate composition, a metal foil hoop is required and a joining (welding) process is also required. In addition, although the hardness of the substrate in the active material non-filled portion of the substrate is increased and deformation of the substrate in the portion is suppressed, it reaches the active material filled portion without weakening the pressing force. However, there was a drawback that a sufficient effect could not be obtained.

  The present invention has been made in view of the above-described problems of the prior art, and the current collector terminal is bonded to the end surface of the substrate in the exposed portion of the substrate without causing deformation at the end of the substrate or dropping of the active material from the substrate. It is something that makes it possible to do.

  In order to solve the above-described problem, the alkaline storage battery according to the present invention includes an electrode plate group in which a rectangular positive electrode plate and a negative electrode plate are stacked via a separator, and at least one of the positive electrode plate and the negative electrode plate. Is an active material supported on a metal substrate made of a three-dimensional porous body, and one long side end of the positive electrode plate is connected to one end surface of the electrode plate group and the end surface of the electrode plate group. A long-side end portion of the negative electrode plate is protruded from the opposing end surface, and a rectangular active material non-filling portion having the long side as one side is provided at the long-side end portions of the positive electrode plate and the negative electrode plate to form the long side. In an alkaline storage battery in which a metal current collector terminal plate is joined to end faces of a positive electrode plate and a negative electrode substrate, a rectangular substrate uncompressed portion having the long side as one side is formed on the substrate made of the three-dimensional porous body. The substrate non-compressed part, the active material non-filling part and the active material filling part Providing a substrate compression portion of the strip between the boundaries.

  In this invention, it is preferable to arrange | position so that the said board | substrate uncompressed part may not oppose a counter electrode. By adopting the configuration of the electrode plate group as the configuration, in the step of attaching the current collecting terminal to the end surface of the substrate, the non-compressed region of the substrate is deformed by the pressing force applied to the end surface of the substrate when the current collecting terminal is joined, and the thickness thereof Even if the thickness of the electrode plate is exceeded, the possibility that the substrate penetrates the separator and contacts the counter electrode can be eliminated.

  In the present invention, the width (short side length) of the non-compressed portion of the substrate is preferably 0.2 mm or more and 1.5 mm or less, and more preferably 0.5 mm or more and 1.2 mm or less. . By setting the width (short side length) of the uncompressed portion of the substrate to 1.5 mm or less, the step of attaching the current collecting terminal to the end surface of the substrate is performed by the pressing force applied to the end surface of the substrate during the current collecting terminal joining. Even if the non-compressed portion is deformed, the thickness of the substrate of the portion can be prevented from exceeding the thickness of the electrode plate. When a pressing force is applied to the non-compressed region of the substrate, the substrate is deformed and absorbs the pressing force. By setting the width (short side length) of the substrate non-compressed region to 0.5 mm or more, the pressing force can be prevented from reaching the substrate compressed region following the substrate non-compressed region.

In the alkaline storage battery according to the present invention, the compression ratio of the band-shaped region is preferably 10 to 60%, and more preferably 20 to 40%. By setting the compression rate to 10% or more, the hardness of the substrate in the compressed portion of the substrate can be increased, and even when a pressing force is applied to the region, it can withstand and prevent deformation. In addition, when the substrate is compressed, the hardness increases, and the substrate is strong against pressing but weak against bending. If the compression ratio exceeds 60%, the substrate is likely to be broken at the compressed portion of the substrate, such being undesirable. Note that the compression ratio here refers to the cross-sectional area before compression (W ₂ × T ₁ ) of the cross-sectional area of the substrate of the compressed portion after compression (the portion provided with a plurality of points in FIG. 1A). Say ratio.

  In the alkaline storage battery according to the present invention, the width of the substrate compression portion is preferably 0.2 to 1.2 mm, and more preferably 0.4 to 1.0 mm. The substrate compression portion has a large hardness and suppresses the active material from dropping due to deformation (swelling) of the substrate. If the width of the substrate compression portion is less than 0.2 mm, the effect of preventing the pressing force from being transmitted to the active material filling region is small. Also. If the width of the substrate compression portion exceeds 1.2 mm, the substrate is likely to be broken at the substrate compression portion, which is not preferable.

  According to claim 1 of the present invention, in an alkaline storage battery comprising an electrode plate formed by joining a current collecting terminal to an end face of a substrate comprising a substrate from a three-dimensional porous body, the deformation of the substrate and the active material It is possible to provide an alkaline storage battery that suppresses dropping and has no risk of an internal short circuit.

  According to claims 2 to 5 of the present invention, it is possible to provide an alkaline storage battery in which the effect of the invention according to claim 1 is further enhanced.

  In the alkaline storage battery according to the present invention, the substrate of at least one of the positive electrode plate and the negative electrode plate is a three-dimensional porous material, specifically, a sponge-like porous material such as foamed nickel or a number of nickel fibers. It is a felt-like (matte) metal porous body that is entangled and sintered.

  In the alkaline storage battery according to the present invention, a band-like region of the substrate between an end portion in contact with the long side of the electrode plate of the active material non-filled portion and a boundary between the active material non-filled portion and the active material filled portion. And the apparent density of the substrate in the compressed portion is made higher than the apparent density of the substrate in the non-compressed portion provided at the end of the active material unfilled portion in contact with the long side.

An example of the electrode plate of the alkaline storage battery according to the present invention is shown in FIG. 1A is a partial cross-sectional view of the electrode plate, and FIG. 1B is a partial plan view of the electrode plate. In FIG. 1, 2 is an active material filling portion of the electrode plate 1, and 3 is a substrate uncompressed portion of the substrate exposed portion. Reference numeral 4 denotes a substrate compression portion of the substrate exposed portion. The substrate compression portion 4 is formed by compressing a substrate exposed portion with a predetermined compression rate by pressing it using a mold, and is formed in a band shape between the substrate non-compressed portion and the active material filling portion 2. Provide. The cross-sectional shape of the substrate compression portion is not particularly limited. For example, in addition to the shape shown in FIG. 1 (a), for example, as shown in FIG. 2 (a), (b), and (c). Various shapes such as a shape can be used. However, as described above, the compression ratio of the compressed portion of the substrate is preferably 10 to 60%, and the width W ₂ is preferably 0.2 to 1.5 mm.

  By setting the substrate in such a configuration, the hardness of the compressed portion provided in a band shape in the active material non-filled portion of the substrate is increased. Therefore, when the current collector terminal plate is brought into close contact with the end surface of the substrate, deformation occurs in the non-compressed portion provided in the portion in contact with the long side of the substrate. There is no possibility that the thickness of the electrode exceeds the thickness of the electrode plate. Further, the pressing force is absorbed by the deformation of the substrate in the non-compressed region, and the pressing force transmitted to the compressed region of the substrate is weakened. Further, since the hardness of the substrate is increased by the compression as described above, the substrate in the compression region does not reach due to the pressing force. Furthermore, the active material-filled portion of the substrate is not deformed, and there is no possibility of the active material falling off.

  Hereinafter, a cylindrical nickel-metal hydride storage battery having a wound electrode group will be taken as an example, and the details of the present invention will be described based on the examples. The shape and the like of the present invention are not limited to the examples shown below.

(Example 1)
A predetermined amount of a carboxymethyl cellulose (CMC) aqueous solution with a predetermined concentration was added to and kneaded with an active material powder having an average particle diameter of 10 μm, on which a coating layer made of cobalt oxyhydroxide was formed on the surface of high-density nickel hydroxide in which zinc and cobalt were dissolved. The positive electrode paste was filled into a foamed nickel substrate having a thickness of 1.3 mm and a basis weight of 420 g / m ² , dried, and then rolled to a thickness of 0.5 mm. A positive electrode original plate was obtained. The original plate was cut into a rectangle having a long side of 650 mm and a short side of 50 mm, an active material having a width of 1.5 mm was removed on one long side, and an exposed portion of the substrate was provided at the end (filling of the positive plate active material) The length of the short side of the part was 48.5 mm). The positive electrode plate has a height of 50 mm, a length of 650 mm, a thickness of 0.5 mm, and a capacity of 8 Ah.

A portion of the positive electrode plate that is in contact with the active material filling portion is pressed and compressed into a band shape, and the substrate exposed portion has a cross-sectional shape shown in FIG. 1 (a), with a width (W ₂ ) of 0.7 mm, A substrate compression portion having a compression rate of 40% and a substrate thickness T ₂ of 0.3 mm at the compressed neck portion was provided.

  The negative electrode plate has a thickness of 0.06 mm and a diameter of 1 mm, mainly composed of a hydrogen storage alloy powder having an average particle size of 40 μm, a binder composed of a predetermined amount of polytetrafluoroethylene powder, and an aqueous solution of carboxymethyl cellulose. Is applied to a nickel-plated punched steel substrate having an aperture ratio of 40%. The length of the short side of the active material filling portion is 48.5 mm, and the length of the long side is The thickness is 720 mm, the thickness is 0.33 mm, and the capacity is 14 Ah. Similarly to the positive electrode, the negative electrode was provided with a substrate exposed portion having a width of 1.5 mm at the end of the long side (the length of the short side of the negative electrode plate was 48.5 + 1.5 = 50 mm).

  The strip-like positive electrode plate and negative electrode plate were wound through a nonwoven fabric as a separator to form a cylindrical electrode plate group having a diameter of 30 mmφ and a height of 51.5 mm. When producing the electrode plate group, the positive electrode plate and the negative electrode plate are shifted by 1.5 mm in the width direction so that the active material filling portions of the positive electrode plate and the negative electrode plate overlap, and the active material filling portions of the positive electrode plate and the negative electrode plate overlap each other. Then, the substrate is wound in a state where the substrate uncompressed portion of the positive electrode plate is laminated so as not to overlap the negative electrode plate. It protruded from the other winding end face of the plate group.

  The substrate end surface of the positive electrode plate projected from one winding end surface of the electrode plate group is made of a nickel plate having an outer diameter of 29.5 mmφ, an inner diameter of 4 mmφ, and a thickness of 0.2 mm, as shown in FIG. In this way, a disk-shaped positive current collector extending in four directions from the center to the outside and having a notch 25 with a width of 1.5 mm (but not having a convex piece 26) is placed and joined by series spot welding. did. There were 16 welding points, 4 on each side of the notch. Further, a current collecting terminal that was the same as the positive electrode current collecting terminal was prepared except that a circular hole was not provided at the center, and the current collecting terminal was joined to the end face of the negative electrode substrate in the same manner as in the case of the positive electrode.

  The positive electrode current collecting terminal and the positive electrode lead plate were joined by welding, and connected to a battery lid that also served as the positive electrode plate and the positive electrode terminal. Moreover, the center part of the negative electrode current collection terminal was joined to the inner bottom face of the battery case also serving as the negative electrode current collection terminal by welding. Next, 10.7 ml of an electrolyte mainly composed of an aqueous potassium hydroxide solution was injected and sealed by a known method to obtain a D size cylindrical battery. This battery is referred to as Example 1.

(Example 2 to Example 4)
In Example 1, the compression ratio of the compressed portion of the positive electrode substrate is 20% {T ₂ shown in FIG. 1 (a) is 0.4 mm}, 60% (T ₂ is 0.2 mm), 10% (T ₂ is 0.45 mm), and the rest of the configuration was the same as in Example 1. The batteries are referred to as Example 2, Example 3, and Example 4, respectively.

(Examples 5 to 8)
In Example 1, the width (W ₁ ) of the non-compressed portion of the positive electrode substrate and the width W ₂ of the compressed portion of the positive substrate without changing the length of the short side of the active material filling portion were 0.4 mm, 1 The thickness was set to 0.0 mm, 0.2 mm, and 1.2 mm so that the active material filling portions of the positive electrode plate and the negative electrode plate overlapped. The rest of the configuration was the same as in Example 1. The batteries are referred to as Example 5, Example 6, Example 7, and Example 8, respectively.

(Example 9 to Example 12)
In Example 1, the width W ₁ of the non-compressed portion of the positive electrode substrate was set to 0.2 mm and 0 mm without changing the width (W ₂ ) of the compressed portion of the positive substrate and the length of the short side of the active material filling portion, respectively. The layers were laminated so that the active material filling portions of the positive electrode plate and the negative electrode plate overlap each other. The rest of the configuration was the same as in Example 1. The batteries are referred to as Example 9, Example 10, Example 11, and Example 12, respectively.

(Comparative Example 1)
In Example 1, the positive electrode substrate was not provided with a compression portion. The rest of the configuration was the same as in Example 1. This battery is referred to as Comparative Example 1.

(Comparative Example 2)
In Example 6, the substrate non-compressed portion was not provided between one long side of the positive electrode substrate and the compressed portion. Otherwise, the configuration was the same as in Example 6.

(Chemical formation)
Fifty batteries according to Examples 1 to 11 and Comparative Examples 1 and 2 were prepared and left at room temperature for 24 hours after battery assembly, and then formed at an ambient temperature of 20 ° C. The first charge was charged at 1/30 ItA for 30 hours, and then charged at 1/10 ItA for 6 hours. After the first charge, the battery was discharged at 1/5 ItA with a final voltage of 1.0V. From the 2nd cycle to the 10th cycle, after charging for 6 hours at 1/10 ItA, charging / discharging was repeated at 1/5 ItA with a final voltage of 1.0 V and a discharge of 1 cycle. During the chemical conversion step, the battery voltage was monitored for all the batteries to check for the occurrence of abnormalities.

(Dismantling survey)
After the chemical conversion is completed, all the batteries are disassembled, and the positive electrode substrate is deformed (curved or swollen and the thickness of the substrate exceeds the thickness of the electrode plate and the positive electrode substrate is broken). The presence or absence of the falling off of the active material of the positive electrode plate was examined.

  Table 1 shows the occurrence of abnormal battery voltage during the formation and the results of the dismantling investigation after the formation.

表１に示したように、比較例１で６個、比較例２で３個電池電圧異常品が認められた。これら電池電圧異常品は、初回の充電で電圧が規定値にまで上昇しなかったので、途中で充電を打ち切り解体調査に回した。解体調査の結果比較例１の電圧異常品６個全てに正極基板の膨れと活物質の脱落が観察され、変形した正極基板または脱落した活物質塊の何れかがセパレータを貫通して内部短絡を起こしたものと推定された。また、比較例２では電圧異常が認められた３個の電池全てに、正極基板の極度（９０度ないしそれを超える角度に折れている）の首折れおよび活物質の脱落が認められ、比較例１と同様、変形した正極基板または脱落した活物質塊の何れかがセパレータを貫通して内部短絡を起こしたものと推定された。比較例１では基板露出部分に基板圧縮部分を設けなかったために基板の変形（膨れや湾曲）が発生したものと考えられる。また、比較例２では、基板露出部分の長辺と基板圧縮部分の間に基板非圧縮部分を設けなかったために、集電端子を接合する時に基板に加わる押圧力を吸収できずに基板圧縮部分に首折れが発生したものと考えられる。

As shown in Table 1, 6 battery voltage abnormal products were found in Comparative Example 1 and 3 battery samples in Comparative Example 2. Since the voltage did not rise to the specified value in the first charge, these battery voltage abnormal products were discontinued during charging and sent for dismantling investigation. As a result of the dismantling investigation, swelling of the positive electrode substrate and falling off of the active material were observed in all six voltage abnormal products of Comparative Example 1, and either the deformed positive electrode substrate or the dropped active material lump penetrated the separator and caused an internal short circuit. Presumed to have occurred. Further, in Comparative Example 2, all of the three batteries in which voltage abnormality was observed showed that the positive electrode substrate was severely broken (folded at an angle of 90 degrees or more) and the active material was dropped. As in Example 1, it was estimated that either the deformed positive electrode substrate or the dropped active material mass penetrated the separator and caused an internal short circuit. In Comparative Example 1, it is considered that the substrate was deformed (swelled or curved) because the substrate compression portion was not provided in the substrate exposed portion. Further, in Comparative Example 2, since the substrate non-compressed portion was not provided between the long side of the substrate exposed portion and the substrate compressed portion, the pressing force applied to the substrate when the current collecting terminal was joined could not be absorbed and the substrate compressed portion It is probable that a neck break occurred.

  In addition, as a result of disassembling and investigating the total number of batteries, in Comparative Example 1, 10 positive electrode substrates were deformed among those in which no voltage abnormality was observed, and active material loss occurred 3 were recognized. In the case of Comparative Example 2 as well, six samples in which the positive electrode substrate was deformed and one sample in which the active material was removed were observed.

On the other hand, in the example batteries, no abnormal voltage product was observed in all the batteries. However, 3 in Example 3, 2 in Example 8 and Example 9, and slight neck bending (bending) were recognized in the positive electrode substrate. In the case of Example 3, the compression ratio of the substrate compression portion is as high as 60%, and in the case of Example 8, the width W ₂ of the substrate compression portion is as large as 1.2 mm, so that the substrate compression portion is bent. is there. In Example 9, since the width W1 of the non-compressed portion of the substrate was as small as 0.2 mm, the pressing force when welding the substrate to the current collecting terminal could not be absorbed, and the compressed portion of the substrate was bent. Is. However, in these batteries, since the degree of deformation was slight, the internal short circuit was not reached.

  In Example 4, two pieces were used, in Example 12, four pieces, and the degree was lighter than that of Comparative Example 1, but swelling and bending were observed in the positive electrode substrate. In Example 12, since the width of the non-compressed portion of the substrate is as large as 1.5 mm, the uncompressed portion of the substrate is swollen or curved. In addition, two pieces in Example 4 and one piece in Examples 7 and 9 were observed to drop out of the fine active material. In the case of the battery of the example, the substrate was deformed, or the active material was dropped. In either case, the degree was less than that of the comparative example, and the non-compressed portion of the positive electrode plate was the negative electrode plate. It is thought that the short circuit did not occur because it did not overlap. On the other hand, in Example 1, Example 2, Example 5, Example 6, Example 10, and Example 11, no deformation of the positive electrode substrate and dropout of the active material were observed.

From the above results, it is provided with an electrode plate group in which a rectangular positive electrode plate and a negative electrode plate are laminated via a separator, and at least one of the positive electrode plate and the negative electrode plate is a metal substrate made of a three-dimensional porous body. An active material is supported on one end face of the positive electrode plate group on one end face of the electrode plate group, and an end face of the negative electrode plate on the end face facing the end face of the electrode plate group. Protruding, providing a rectangular active material non-filling portion with the long side as one side at the end of the long side of the positive electrode plate and the negative electrode plate, and making metal on the end surfaces of the positive electrode plate and the negative electrode plate forming the long side In the alkaline storage battery to which the current collector terminal plate is bonded, as in the battery according to the present invention, the substrate made of the three-dimensional porous body is provided with a rectangular substrate uncompressed portion having the long side as one side, A band-like base is formed between the uncompressed portion of the substrate and the boundary between the active material unfilled portion and the active material filled portion. By providing the compression part can fall off suppression of deformation and the active material of the substrate, it has been found that it is possible to prevent the occurrence of internal short circuit.
When a three-dimensional porous substrate is provided Further, in order to prevent deformation of the substrate and dropping of the active material, the compression ratio of the compressed portion of the substrate is preferably 10 to 60%, more preferably 20 to 40%. More preferably, the width W ₂ of the compressed portion of the substrate is preferably 0.2 to 1.2 mm, more preferably 0.4 to 1.0 mm, It has been found that the width W _{1 of the} compressed portion is preferably 0.2 to 1.5 mm, and more preferably 0.5 to 1.2 mm.

  As described above, the nickel hydride storage battery having the wound electrode plate has been described in detail, but the present invention is not limited to this, and the storage battery having the stacked electrode plate group shown in FIG. Applicable. Moreover, it is applicable also to alkaline storage batteries other than nickel hydride storage batteries, such as a nickel cadmium storage battery. In the above-described embodiments, the positive electrode plate is provided with a three-dimensional porous substrate. However, when the negative electrode plate is provided with a three-dimensional porous substrate, or both the positive electrode plate and the negative electrode plate are three-dimensional porous substrates. It is also effective when provided with. In the present invention, as shown in FIG. 1 (a), the substrate compression portion and the active material filling portion may be in contact with each other, or in FIGS. 2 (a), (b) and (c). As shown, a substrate uncompressed portion may exist between the substrate compressed portion and the active material filled portion.

It is the fragmentary sectional view and partial plan view of the electrode plate for alkaline storage batteries which concerns on this invention. It is a fragmentary sectional view of the electrode plate for alkaline storage batteries concerning the present invention. It is explanatory drawing which shows one structural example of the winding type | formula electrode group of an alkaline storage battery. It is a perspective view which shows one example of the current collection terminal applied to the winding type electrode group of an alkaline storage battery. It is a perspective view which shows 1 structural example of the laminated type electrode group of an alkaline storage battery. It is a fragmentary sectional view showing an example of the conventional electrode plate. It is a schematic diagram which shows the process of joining a current collection terminal to the board | substrate end surface of an electrode plate. It is a fragmentary sectional view showing an example of the conventional electrode plate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode plate 2 Active material filling part 3 Substrate uncompressed part 4 Substrate compression part 11 Winding type electrode plate group 11A 11B Winding end surface of winding type electrode plate group 17 18 It protrudes on the winding end surface of winding type electrode plate group Collected substrate end 20 22 Current collector terminal of wound electrode group 32 34 Substrate end projected on end surface of stacked electrode group 36 37 Current collector terminal of stacked electrode group

Claims (5)

An electrode plate group in which a rectangular positive electrode plate and a negative electrode plate are stacked via a separator is provided, and at least one of the positive electrode plate and the negative electrode plate carries an active material on a metal substrate made of a three-dimensional porous body. The positive electrode plate has one long side end portion of the positive electrode plate protruding from one end surface of the electrode plate group, and the long side end portion of the negative electrode plate protruded from the end surface facing the end surface of the electrode plate group. In addition, a rectangular substrate exposed portion having the long side as one side is provided at the end of the long side of the negative electrode plate, and a metal current collector terminal plate is bonded to the end surface of the positive electrode plate and the negative plate substrate forming the long side In the alkaline storage battery, the substrate made of the three-dimensional porous body is provided with a rectangular substrate uncompressed portion having the long side as one side, and the substrate uncompressed portion, the substrate exposed portion, and the active material filling portion Alkaline storage battery characterized in that a band-like substrate compression portion is provided between the boundaries The alkaline storage battery according to claim 1, further comprising an electrode plate group disposed so that the substrate non-compressed portion does not face the counter electrode. 2. The alkaline storage battery according to claim 1, wherein a width (length of a short side) of the non-compressed portion of the substrate is 0.2 to 1.5 mm. 2. The alkaline storage battery according to claim 1, wherein the compression ratio of the substrate compression portion is 10 to 60%. 2. The alkaline storage battery according to claim 1, wherein the width of the substrate compression portion is 0.2 to 1.2 mm.

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