JP2020123447A - Lead-acid battery - Google Patents

Abstract

To provide a lead acid battery of which the lifetime is prolonged by making a separator hard to be destroyed even if an external stress is received from a deformed positive electrode plate.SOLUTION: An collector ear 11 and a protrusion 12 which protrudes lower than the collector ear 11, are formed at an upper edge of a positive electrode plate 10. A separator 30 includes: a base part 31; multiple main ribs 32 which protrude from a surface of the base part 31 opposed to the positive electrode plate 10 and are brought into contact with the positive electrode plate 10; and multiple small ribs 33 which protrude from the surface of the base part 31 opposed to the positive electrode plate 10 and protrude lower than the main ribs 32. The main ribs 32 are formed in a central part 30a of the surface of the base part 31 opposed to the positive electrode plate 10 in a lateral width direction, and the small ribs 33 are formed in an end portion 30b of the surface of the base part 31 opposed to the positive electrode plate 10 in the lateral width direction. Among the main ribs 32, the main rib 32 which is disposed closest to the end portion in the lateral width direction is positioned on a portion of the base part 31 opposed to the protrusion 12.SELECTED DRAWING: Figure 4

Description

The present invention relates to lead acid batteries.

The lead acid battery has a problem that a short circuit occurs due to the breakage of the separator and the life is shortened. The main causes of separator breakage are oxidative deterioration and external stress.
First, oxidative deterioration will be described. The separator may be broken due to oxidative deterioration due to contact with the positive electrode plate. Therefore, in order to suppress direct contact between the surface of the separator and the positive electrode plate, a technique of providing ribs on the surface of the separator is widely adopted.

Next, the external stress will be described. The separator may be broken by external stress received from the deformed positive electrode plate. The positive electrode plate extends due to oxidation, but when the end portion of the positive electrode plate bends toward the separator, the end portion of the positive electrode plate strongly presses the surface of the separator. More specifically, since the rib is provided on the surface of the separator, the end of the positive electrode plate strongly presses the rib on the surface of the separator. If the warp or elongation of the positive electrode plate further progresses in such a state, the surface of the separator is pulled together with the ribs, so that the separator having a relatively low strength cannot follow the elongation due to the tension and is torn like a tear.

JP-A-3-149748

An object of the present invention is to provide a lead storage battery in which the separator is not easily broken even when external stress is applied from the deformed positive electrode plate and which has a long life.

A lead-acid battery according to an aspect of the present invention is a lead-acid battery that includes a positive electrode plate and a negative electrode plate, and a positive electrode plate including a plurality of electrode plates alternately stacked with a separator interposed therebetween. , A current collecting ear protruding upward, and a protruding portion protruding upward of the positive electrode plate and having a protruding height lower than that of the current collecting ear are formed at intervals in the lateral width direction of the separator. Is a film-shaped base portion, a plurality of main ribs protruding from the surface of the base portion facing the positive electrode plate and contacting the positive electrode plate, and protruding from the surface of the base portion facing the positive electrode plate and having a lower protrusion height than the main ribs. A plurality of small ribs, the main rib is formed in a continuous linear shape along the vertical direction of the separator, and is formed in the central portion in the lateral width direction of the separator of the surface of the base portion facing the positive electrode plate. The small rib is formed in a continuous linear shape along the vertical direction of the separator, and is formed at the end of the separator in the lateral width direction of the surface of the base portion facing the positive electrode plate, and the small rib is formed. The widthwise end is the widthwise end whose distance from the protruding portion is smaller than the distance from the current collecting ear, and is the main rib that is arranged closest to the widthwise end of the main rib. The gist is that the rib is located on a portion of the base portion facing the protrusion.

The lead storage battery according to the present invention has a long service life because the separator is not easily broken even when external stress is applied from the deformed positive electrode plate.

It is a fragmentary sectional view explaining the structure of the lead acid battery which concerns on 1st embodiment of this invention. It is a figure explaining the board|substrate used for a positive electrode plate. It is a figure explaining the connection body sheet for manufacturing the board|substrate of FIG. It is a figure which shows the structure of the principal part of the electrode plate group which the lead acid battery of FIG. 1 has. 6 is a diagram showing a structure of a main part of an electrode plate group included in the lead storage battery of Example 2. FIG. It is a figure which shows the structure of the principal part of the electrode plate group which the lead acid battery of Example 3 has. It is a figure which shows the structure of the principal part of the electrode plate group which the lead acid battery of Example 4 has. It is a figure which shows the structure of the principal part of the electrode plate group which the lead acid battery of Example 5 has. It is a figure which shows the structure of the principal part of the electrode plate group which the lead acid battery of a prior art example has. 5 is a diagram showing a structure of a main part of an electrode plate group included in the lead storage battery of Comparative Example 1. FIG. 7 is a diagram showing a structure of a main part of an electrode plate group included in a lead storage battery of Comparative Example 2. FIG. 8 is a diagram showing a structure of a main part of an electrode plate group included in a lead storage battery of Comparative Example 3. FIG. 11 is a diagram showing a structure of a main part of an electrode plate group included in the lead storage battery of Comparative Example 4. FIG. 9 is a diagram showing a structure of a main part of an electrode plate group included in a lead storage battery of Comparative Example 5. FIG. 9 is a diagram showing a structure of a main part of an electrode plate group included in a lead storage battery of Comparative Example 6. FIG. It is a graph which shows the result of the life test of each lead acid battery. It is a figure explaining the structure of the separator which the lead acid battery which concerns on 2nd embodiment of this invention has. It is a figure explaining the structure of the separator which the lead acid battery which concerns on 3rd embodiment of this invention has.

An embodiment of the present invention will be described. The embodiment described below is an example of the present invention, and the present invention is not limited to this embodiment. Further, various changes or improvements can be added to the present embodiment, and a mode in which such changes or improvements are added can also be included in the present invention.

[First embodiment]
The structure of the lead storage battery according to the first embodiment of the present invention will be described in detail with reference to FIG. The lead storage battery according to the first embodiment includes an electrode plate group 1 in which a plurality of positive electrode plates 10 and negative electrode plates 20 are alternately stacked with a separator 30 in between. The electrode plate group 1 is housed in the battery case 41 together with an electrolytic solution (not shown) so that the stacking direction is along the horizontal direction (that is, the plate surfaces of the positive electrode plate 10 and the negative electrode plate 20 are along the vertical direction). And is immersed in the electrolytic solution in the battery case 41.

In the positive electrode plate 10, for example, while filling the positive electrode active material containing lead dioxide into the openings of the plate-shaped grid body made of a lead alloy, both surfaces of the plate grid made of the lead alloy are coated with lead dioxide. An active material layer (denoted by reference numeral 10a in FIG. 4) made of the contained positive electrode active material is formed. The negative electrode plate 20 is, for example, filled with metal lead on both plate surfaces of a plate-shaped grid body made of a lead alloy while filling an opening of the plate-shaped grid body made of a lead alloy with a negative electrode active material containing metal lead. An active material layer (denoted by reference numeral 20a in FIG. 4) made of the contained negative electrode active material is formed. The plate-shaped lattice bodies that are the substrates of the positive electrode plate 10 and the negative electrode plate 20 can be manufactured by a casting method, a punching method (punching method), or an expanding method. The separator 30 is, for example, a porous film body made of resin, glass, or the like. The planar shapes of the positive electrode plate 10, the negative electrode plate 20, and the separator 30 may be rectangular, for example.

At the upper edge portion of the positive electrode plate 10 (the substrate) (that is, the upper edge portion of the edge portion of the positive electrode plate 10), a current collector projecting upward of the positive electrode plate 10 (upward in FIG. 1). The ears 11 are formed, and at the upper edge portion of the negative electrode plate 20, there is formed a current collecting ear 21 that protrudes upward (upward in FIG. 1) of the negative electrode plate 20. The current collecting ears 11 of each positive electrode plate 10 are connected by a positive electrode strap 13, and the current collecting ears 21 of each negative electrode plate 20 are connected by a negative electrode strap 23. Further, the positive electrode strap 13 is connected to one end of the positive electrode terminal 15, the negative electrode strap 23 is connected to one end of the negative electrode terminal 25, and the other end of the positive electrode terminal 15 and the other end of the negative electrode terminal 25 are connected to the opening of the battery case 41. It penetrates through the lid 43 that closes the part, and is exposed to the outside of the case body of the lead storage battery including the battery case 41 and the lid 43.

Further, as shown in FIG. 2, at the upper edge portion of the positive electrode plate 10 (substrate), a protruding portion 12 protruding upward of the positive electrode plate 10 and having a protruding height lower than that of the current collecting ear 11 is provided. With respect to the current collecting ears 11 of 10, the width direction of the separator 30 (the front-back direction with respect to the paper surface in FIGS. 1 and 2B, and the left-right direction in FIG. 2A). , May be simply referred to as “width direction”). Similar to the positive electrode plate 10, the protruding portion 12 may be formed on the upper edge portion of the negative electrode plate 20, but may not be formed.

An example of the protruding portion 12 is an uncut portion that is produced when the plate-shaped lattice body that is the substrate of the positive electrode plate 10 is manufactured. The method of manufacturing the plate-like lattice body and the uncut portion will be described in detail with reference to FIGS. In the case of manufacturing a plate-shaped lattice body by a punching method, first, a lead alloy rolling plate is punched to manufacture a connected body sheet 100 in which a plurality of plate-shaped lattice bodies are connected, and then the connected body sheet 100 is cut. To obtain a plate lattice.

An example of the connected body sheet 100 is shown in FIG. FIG. 3 is a plan view of a connected body sheet 100 in which six plate-shaped lattice bodies are connected. The connected body sheet 100 of FIG. 3 has the following configuration. That is, the upper edge portions of the two plate-like lattices are connected by the two connecting portions 11a, which are the portions to be the current collecting ears 11, and further, the three side-by-side connected portions are arranged side by side. By connecting, the connected sheet 100 of FIG. 3 is formed.

When the connecting sheet 100 shown in FIG. 3 is cut using a cutter or the like, the end portion of the connecting portion 11a and the side edge portion of the plate-like lattice body are separated into six plate-like lattice bodies. At this time, when the connecting portion 11a is cut, the two plate-like lattices are connected so that the collector ears 11 are formed in each of the plate-like lattices obtained by cutting. Regarding the connecting portion 11a, the ends on different sides are cut.

When cutting the connecting portion 11a, it is ideal to cut along the boundary between the connecting portion 11a and the upper edge of the plate-like lattice so that no uncut portion is left. In order to surely prevent the upper edge portion of the lattice-like body from being scratched, it is preferable to cut the connecting portion 11a with a cutting margin. As a result, the uncut portion remains at the upper edge of the plate-like lattice. The protruding height from the upper edge of the uncut portion is not particularly limited, but can be, for example, 1 mm or more and 3 mm or less.

The type of cutting instrument used for cutting the connecting portion 11a is not particularly limited, but a cutter such as a rotary cutter can be used, for example. The shape of the protruding tip of the uncut portion (projecting portion 12) also depends on the shape of the blade of the cutter and the cutting method. For example, in the case of cutting using a rotary cutter, the blade is brought into contact with one surface of the connecting portion 11a to start cutting, and the blade is bited toward the other surface of the connecting portion 11a. The projecting height from the upper edge of the uncut portion is different between the one surface side that bites into the root of the blade and the other surface side that reaches only the blade tip. That is, as shown in FIG. 2B, the shape of the protruding tip of the uncut portion (protruding portion 12) is such that the surface of the other surface is more than the surface of the other surface (left side in FIG. 2B). The side (the right side in FIG. 2B) has a shape in which the protruding height from the upper edge of the uncut portion is higher.

As shown in FIG. 4, the separator 30 includes a film-shaped base portion 31, a plurality of main ribs 32 protruding from a surface of the base portion 31 facing the positive electrode plate 10 and in contact with the positive electrode plate 10, and a positive electrode plate of the base portion 31. And a plurality of small ribs 33 protruding from the surface facing 10 and having a lower protruding height than the main rib 32. The small rib 33 does not contact the positive electrode plate 10 when the positive electrode plate 10 is not deformed or when the positive electrode plate 10 is slightly deformed.

The main rib 32 is formed in a continuous linear shape along the vertical direction of the separator 30, and is formed on the central portion 30 a in the lateral width direction of the separator 30 on the surface of the base portion 31 facing the positive electrode plate 10.
The small ribs 33 are linearly formed along the vertical direction of the separator 30 and are formed on the end portion 30b in the lateral width direction of the separator 30 on the surface of the base portion 31 facing the positive electrode plate 10. The lateral width direction end portion 30b in which the small rib 33 is formed is one of the two lateral width direction end portions 30b and 30b that are positioned with the lateral width direction central portion 30a interposed therebetween, and the protruding portion 12 is longer than the distance from the current collecting ear 11. It is the lateral width direction end portion 30b having a smaller distance from.

A main rib 32 is formed at the lateral width direction end 30b whose distance from the current collecting ear 11 is smaller than the distance from the protrusion 12, but a small rib 33 is formed instead of the main rib 32. It may have been done. That is, the separator 30 may have a form in which the lateral width direction central portion 30a where the main rib 32 is formed is sandwiched between the lateral width direction end portions 30b and 30b where the small rib 33 is formed.

In addition, the base portion 31 of the separator 30 has two lateral width direction end portions 30b, but in the following, the lateral width direction in which the distance to the protruding portion 12 is smaller than the distance to the current collecting ear 11 is the lateral width direction. The end portion 30b (the end portion 30b on the right side in FIG. 4) may also be referred to as a “protruding portion-side end portion”, and the lateral width of the smaller distance from the current collecting ear 11 than the distance from the protruding portion 12 is. The direction end portion 30b (the end portion 30b on the left side in FIG. 4) may be referred to as a “current collecting ear end portion”. Similarly, in the lateral width direction, the side (the right side in FIG. 4) having a smaller distance to the protruding portion 12 than the distance to the current collecting ear 11 is referred to as the “protruding portion-side end portion side” and the protruding portion 12. The side closer to the current collecting ear 11 than the distance (left side in FIG. 4) may be referred to as the “end side closer to the current collecting ear”.

In the lead storage battery according to the first embodiment as described above, among the main ribs 32, the main rib 32 disposed closest to the end portion in the lateral width direction is the portion of the base portion 31 that faces the protruding portion 12. Located on top (see FIG. 4). In other words, the boundary line B between the lateral width direction central portion 30a where the main rib 32 is formed and the lateral width direction end portion 30b where the small rib 33 is formed is the portion of the base portion 31 that faces the protruding portion 12. Located on top of. In addition, the above-mentioned “end portion in the width direction” is the end portion side in the width direction in which the distance to the protruding portion 12 is smaller than the distance to the current collecting ear 11, that is, the end portion closer to the protruding portion. On the side.

With such a configuration, the lead storage battery according to the first embodiment has a long service life in which the separator 30 is less likely to be broken even when an external stress is applied from the deformed positive electrode plate 10. Therefore, the lead storage battery according to the first embodiment is suitable, for example, as a power source mounted on a vehicle and activating an internal combustion engine of the vehicle. Further, the lead storage battery according to the first embodiment is suitable for use in a high temperature environment. Furthermore, the lead storage battery according to the first embodiment is not only used as a power source for starting an internal combustion engine of a vehicle, but also an electric vehicle, an electric forklift truck, an electric bus, an electric motorcycle, an electric scooter, a small electric moped, a golf cart, It can also be used as a power source for electric locomotives. Furthermore, the lead storage battery according to the present embodiment can be used as a lighting power source and a standby power source. Alternatively, it can be used as a power storage device for electric energy generated by solar power generation, wind power generation, or the like.

The above-mentioned effects of the lead storage battery according to the first embodiment will be described in detail below. When the positive electrode plate 10 is oxidized, the end portion of the positive electrode plate 10 may extend toward the separator 30 so as to bend, and the end portion of the positive electrode plate 10 may strongly press the surface of the separator 30. At this time, if a main rib 32 having a high protruding height is formed on a portion of the surface of the separator 30 where the end portion of the positive electrode plate 10 faces, the end portion of the positive electrode plate 10 will have the main rib on the surface of the separator 30. Squeeze 32 strongly. When the warp or extension of the positive electrode plate 10 further progresses in such a state, the surface of the separator 30 is pulled together with the main ribs 32, so that the separator 30 having a relatively weak strength cannot follow the extension due to the tension and is torn like a tear. It will be.

However, in the lead-acid battery according to the first embodiment, the small rib 33 having a low protruding height is formed at the portion of the surface of the separator 30 where the end of the positive electrode plate 10 faces, and thus the deformed positive electrode plate is formed. Even if the end of 10 contacts the small rib 33, the pressing of the separator 30 by the end of the positive electrode plate 10 is suppressed. Therefore, in the lead storage battery according to the first embodiment, the separator 30 is less likely to be broken and has a long life.

The warp or extension of the end portion of the positive electrode plate 10 becomes larger starting from the uncut portion, and the warp or extension of the portion located on the end side in the lateral width direction than the uncut portion is greater. When the uncut portion does not exist, the warp and the elongation of the end portion of the positive electrode plate 10 become smaller than when the uncut portion does exist. Further, even if the current collecting ears 11 are present, the warp and extension of the end portion of the positive electrode plate 10 do not increase.

According to the study by the present inventors, it has been found that this is due to the shape of the protruding tip of the uncut portion (projecting portion 12). That is, as shown in FIG. 2B, the shape of the protruding tip of the uncut portion (projecting portion 12) is closer to the other surface side than to the one surface side from the upper edge portion of the uncut portion. If the protrusion height is high, a difference occurs in the amount of corrosion and stress distribution (for example, stress distribution due to elongation) on both surface sides. Therefore, it is considered that the end portion of the positive electrode plate 10 bends toward the other surface side where the protrusion height is high, and the warp bend and the extension of the end side portion in the lateral width direction become larger than the uncut portion.

Therefore, if the lateral width direction position of the boundary line B between the lateral width direction central portion 30a where the main rib 32 is formed and the lateral width direction end portion 30b where the small rib 33 is formed is set with reference to the uncut portion. Since the small ribs 33 can be formed at appropriate positions, it is possible to easily and surely design the lead storage battery in which the separator 30 is not easily broken and has a long life.
The projecting height of the small rib 33 is not particularly limited as long as the projecting height is lower than that of the main rib 32, but the projecting height is 25% or more and 75% or less of the projecting height of the main rib 32. Is preferable, and it is more preferable that the protrusion height is 45% or more and 65% or less.

Further, the shape of the protruding tip of the small rib 33 is not particularly limited, and the cross-sectional shape of the protruding tip when the small rib 33 is cut along a plane orthogonal to the vertical direction of the separator 30 is, for example, a triangle, a rectangle, It may be a polygon such as a trapezoid or a pentagon, but it is preferable that the projecting tip has no corner. That is, it is preferable that the protruding end of the small rib 33 has a rounded and smooth shape, and the sectional shape of the protruding end when the small rib 33 is cut along a plane orthogonal to the vertical direction of the separator 30 is, for example, a semicircle. The semi-elliptical shape is preferable.

The shape of the separator 30 is not particularly limited, and may be a bag shape capable of accommodating the positive electrode plate 10 or the negative electrode plate 20, or a positive electrode plate 10 or the negative electrode may be formed by bending a film-like material into a U shape. The plate 20 may be in a sandwichable state, or may be in the form of a film in which the positive electrode plate 10 or the negative electrode plate 20 can be sandwiched by a plurality of plates. The electrode plate accommodated inside the bag-shaped separator 30 may be either the positive electrode plate 10 or the negative electrode plate 20, but the form in which the negative electrode plate 20 is accommodated is more effective in suppressing breakage of the separator 30.

Further, the composition of the electrolytic solution is not particularly limited, and a general electrolytic solution used for a lead storage battery can be applied without any problem. In order to make the lead storage battery excellent in charge acceptance, the electrolytic solution preferably contains aluminum ions, and the content of aluminum ions in the electrolytic solution is 0.01 mol/L or more. It is preferable that However, if the content of aluminum ions in the electrolytic solution is high, it becomes difficult for gas to be discharged to the outside from the electrode plate group 1. Therefore, the content of aluminum ions in the electrolytic solution should be 0.3 mol/L or less. Is preferred.
Further, the electrolytic solution may contain sodium ions. The content of sodium ions in the electrolytic solution can be 0.002 mol/L or more and 0.05 mol/L or less.

Example of First Embodiment
Hereinafter, the present invention will be described more specifically by showing Examples and Comparative Examples.
(Example 1)
The lead acid battery of Example 1 has the same configuration as the lead acid battery shown in FIGS. 1 and 4. The method for manufacturing the lead acid battery of Example 1 will be described below.

First, lead powder, water, dilute sulfuric acid, and short fibers were mixed to produce a positive electrode paste. Next, a rolled plate of calcium lead alloy was punched out to manufacture a connected body sheet 100 in which six plate-shaped lattice bodies were connected as shown in FIG. Then, after filling the positive electrode paste into the openings of the plate-like lattice of the connected body sheet 100, the connected body sheet was cut with a rotary cutter to obtain six positive electrode filled plates.

The size of the plate-like lattice is a rectangular plate having a length of 110 mm, a width of 100 mm, and a thickness of 1.0 mm. A current collecting ear 11 having a width of 10 mm is formed on the upper edge portion of the plate-like lattice. The lateral widthwise position where the current collecting ears 11 are formed at the upper edge of the plate-shaped lattice is the same as the side edge closer to the current collecting ears 11 of both side edges (vertical frames) of the plate-shaped lattice. This is the position where the distance in the widthwise direction from the center of the hearing aid 11 is 33 mm. The projecting height from the upper edge of the current collecting ear 11 was set to a design median value of 17 mm and a tolerance during cutting of ±1 mm.

Further, an uncut portion 12 having a width of 10 mm is formed on the upper edge portion of the plate-like lattice. The lateral width direction position where the uncut portion 12 is formed in the upper edge portion of the plate-shaped grid is cut from the side edge of the plate-shaped grid that is farther from the current collecting ear 11 among both side edges (vertical frame). This is the position where the lateral widthwise distance from the center of the remaining portion 12 is 33 mm. The protrusion height from the upper edge of the uncut portion 12 is set to 1 mm or more and 3 mm or less so as not to scratch the upper edge of the plate-like lattice when the connector sheet 100 is cut.
The positive electrode-filled plate thus obtained was aged and dried by a conventional method to obtain a positive electrode aged plate.
The plate lattice for the negative electrode plate was produced by a continuous casting method. Then, after filling the negative electrode paste in the openings of the plate-like lattice, it was aged and dried by a conventional method to obtain a negative electrode aged plate.

The separator 30 is made of porous synthetic resin and has a film-shaped base portion 31 having a thickness of 0.2 mm, a plurality of main ribs 32 protruding from the surface of the base portion 31 and having a protrusion height of 0.5 mm, and a base. A plurality of small ribs 33 protruding from the surface of the portion 31 and having a protruding height of 0.2 mm. Further, the separator 30 is formed by folding a film-like material having a width of 110 mm and a length of 231 mm so that the surface on the side where the main ribs 32 and the small ribs 33 are formed faces outward, and sealing the both side edges with a bag. It is molded into a shape.

The protruding tip of the small rib 33 has a rounded shape without corners. In addition, the plurality of small ribs 33 are formed on the surface of the base portion 31 facing the positive electrode plate 10 at the end portion 30b closer to the protruding portion of the separator 30 (the distance from the uncut portion 12 than the distance from the collector ear 11). Are formed side by side at intervals of 0.5 mm on the entire lateral width direction end 30b) having a smaller width. That is, the plurality of small ribs 33 are formed side by side at 0.5 mm intervals in a portion between the side edge portion of the separator 30 and a boundary line B described later. Further, the plurality of main ribs 32 are arranged at intervals of 5 mm over the central portion 30a in the lateral width direction of the separator 30 (that is, the portion where the small ribs 33 are not formed) on the surface of the base portion 31 facing the positive electrode plate 10. They are formed side by side.

Of the main ribs 32, the end portion in the lateral width direction (the end portion side closer to the protruding portion, that is, the end portion side in the lateral width direction having a smaller distance to the uncut portion 12 than to the collector ear 11). The main rib 32 arranged in () is located on a portion of the base portion 31 facing the uncut portion 12. That is, the boundary line B between the center portion 30 a in the widthwise direction in which the main rib 32 is formed and the end portion 30 b in the widthwise direction in which the small rib 33 is formed (end portion 30 b near the protrusion) is the base line 31 of the base portion 31. It is located on the portion facing the uncut portion 12. In addition, the main rib 32 disposed on the end side closest to the protruding portion of the main rib 32 is located near the center in the lateral width direction of the portion of the base portion 31 facing the uncut portion 12.

A plurality of the above-mentioned positive electrode aged plate and the above-mentioned negative electrode aged plate were alternately laminated via the separator 30 to manufacture the electrode plate group 1. In this example, 6 positive electrode aged plates and 7 negative electrode aged plates were used. At that time, one negative electrode aging plate is housed inside the bag-shaped separator 30, and the separator 30 is sandwiched between two positive electrode aging plates, so that the main ribs 32 and the small ribs 33 of the separator 30 become the positive electrode aging plate. I made them face each other.
Then, the electrode plate group 1 was housed in the battery case 41 and adjusted with a spacer so that the group pressure was about 5 to 10 kPa, and a lead storage battery having a voltage of 2 V was assembled. Then, the lead acid battery of Example 1 was obtained by injecting the electrolytic solution into the battery case 41 and performing chemical conversion by a conventional method. Note that the positive electrode aged plate and the negative electrode aged plate become the positive electrode plate 10 and the negative electrode plate 20 by the aging.

(Example 2)
FIG. 5 shows a main part of the electrode plate group 1 included in the lead storage battery of Example 2. Except that the main rib 32 arranged closest to the protruding end of the main rib 32 is located closest to the protruding end of the base portion 31 facing the uncut portion 12. Since it is exactly the same as in Example 1, other explanations are omitted.

(Example 3)
FIG. 6 shows a main part of the electrode plate group 1 included in the lead storage battery of Example 3. Except that the main rib 32 arranged closest to the protruding end of the main rib 32 is located closest to the current collecting ear end of the portion of the base 31 facing the uncut portion 12. Since it is exactly the same as in Example 1, other explanations are omitted.

(Example 4)
FIG. 7 shows a main part of the electrode plate group 1 included in the lead acid battery of Example 4. The cross-sectional shape of the protruding tip when the small rib 33 is cut along a plane orthogonal to the vertical direction of the separator 30 is the same as that of the first embodiment except that the protruding tip has a rectangular shape instead of a semicircular shape and has a corner portion. , And other explanations are omitted.

(Example 5)
FIG. 8 shows a main part of the electrode plate group 1 included in the lead storage battery of Example 5. The cross-sectional shape of the protruding tip when the small rib 33 is cut in a plane orthogonal to the vertical direction of the separator 30 is exactly the same as in Example 1 except that it has a triangular shape instead of a semicircular shape and has a corner. , And other explanations are omitted.

(Conventional example)
FIG. 9 shows a main part of the electrode plate group 1 included in the conventional lead-acid battery. Except for the fact that only the main ribs 32 are formed on the surface of the base portion 31 facing the positive electrode plate 10 and the small ribs are not formed, this is exactly the same as in Example 1, and therefore other explanations are omitted.

(Comparative Example 1)
FIG. 10 shows a main part of the electrode plate group 1 included in the lead storage battery of Comparative Example 1. Except for the fact that only the small rib 33 is formed on the surface of the base portion 31 facing the positive electrode plate 10 and the main rib 32 is not formed, it is exactly the same as in the first embodiment, so other explanations are omitted. ..

(Comparative example 2)
FIG. 11 shows a main part of the electrode plate group 1 included in the lead storage battery of Comparative Example 2. The main rib 32 is the same as that of the first embodiment except that the main rib 32, which is arranged closest to the end of the main rib 32 facing the protruding portion, is located in a portion of the base portion 31 that faces the current collecting ear 11. , And other explanations are omitted.

(Comparative example 3)
FIG. 12 shows a main part of the electrode plate group 1 included in the lead storage battery of Comparative Example 3. The main rib 32, which is arranged on the end portion side closest to the protruding portion of the main rib 32, is located in the lateral width direction between the portion of the base portion 31 facing the current collecting ear 11 and the portion of the base rib 31 facing the uncut portion 12. The third embodiment is exactly the same as the first embodiment except that it is located at, so the other description will be omitted.

(Comparative example 4)
FIG. 13 shows a main part of the electrode plate group 1 included in the lead storage battery of Comparative Example 4. The embodiment except that the main rib 32 arranged on the most proximate end side of the main rib 32 is located on the most prominent end side of the portion of the base 31 facing the positive electrode plate 10. Since it is exactly the same as 1, the other description will be omitted. As shown in FIG. 13, the small rib 33 is not formed in the portion of the base portion 31 facing the positive electrode plate 10, and the end portion of the base portion 31 closer to the protrusion than the portion facing the positive electrode plate 10 is. The small rib 33 is formed only on the side

(Comparative example 5)
FIG. 14 shows a main part of the electrode plate group 1 included in the lead storage battery of Comparative Example 5. Since the small ribs are not formed on the end portion 30b of the separator 30 close to the protruding portion, and only the main rib 32 is formed on the base portion 31, it is exactly the same as the first embodiment. Is omitted.

(Comparative example 6)
FIG. 15 shows a main part of the electrode plate group 1 included in the lead storage battery of Comparative Example 6. The main rib 32, which is arranged on the end portion side closest to the protruding portion of the main rib 32, is located in the lateral width direction between the portion of the base portion 31 facing the current collecting ear 11 and the portion of the base rib 31 facing the uncut portion 12. It is exactly the same as the first embodiment except that it is located at. Further, as compared with Comparative Example 3, the position in the lateral width direction where the main rib 32 disposed on the end portion side closest to the protruding portion of the main rib 32 is located is closer to the uncut portion 12. Since there is no difference other than this, the other description will be omitted.

A life test was performed on these lead storage batteries by a method similar to the light load life test defined in JIS D5301. The detailed method of the life test will be described below.
In a 75° C. atmosphere, the lead storage battery is discharged at 25 A for 2 minutes and then charged at 14.8 V (maximum current 25 A) for 10 minutes. Such a process is defined as one cycle, and this cycle is repeated 480 times. Then, each time one cycle is completed, the lead storage battery is left in an atmosphere of 25° C. for 56 hours, after which it is continuously discharged at 280 A for 5 seconds, and the voltage at the 5th second discharge is measured. When the discharge voltage at the 5th second discharge drops to 7.2 V while repeating the above cycle 480 times, it is determined that the life has been reached, and the number of cycles up to that point is defined as the number of life cycles.

Since the water content in the electrolytic solution decreases during the life test, the lead acid battery should be supplemented with purified water as appropriate. In addition, the life test is carried out for two lead storage batteries per type of lead storage battery, one lead storage battery is tested until it reaches the end of its life, and then a disassembly survey is conducted. A disassembly survey was conducted after continuing the test up to the life cycle number of the lead acid battery of the example. If the lead-acid battery had a shorter life than the conventional lead-acid battery, the disassembly survey was performed as it was.

The result of the life test is shown in the graph of FIG. The numerical value of the life cycle number in the graph of FIG. 16 is shown as a relative value when the life cycle number of the conventional example is 100.
From the graph of FIG. 16, it can be seen that the lead storage batteries of Examples 1 to 3 have a longer life than the lead storage batteries of the conventional example and Comparative Examples 1 to 6.

Moreover, when the lead-acid batteries of Examples 1 to 3 were disassembled and examined at the same number of cycles as the life cycle of the conventional example, all of Examples 1 to 3 and the conventional example showed elongation of the positive electrode plate. In particular, the portion from the uncut portion to the end portion of the positive electrode plate near the protruding portion (hereinafter referred to as “the end portion of the positive electrode plate”) was largely curved. In the conventional lead-acid battery, the edge of the positive electrode plate that is stretched and warped presses the main rib of the separator to pull it, causing the separator to rupture and a short circuit.

On the other hand, in the lead-acid batteries of Examples 1 to 3, there is a margin in the amount of bending of the positive electrode plate until the separator is pressed by the difference in the protruding heights of the main rib and the small rib. In the comparison, no breakage of the separator occurred and no short circuit was observed. Further, the end of the bent positive electrode plate was in contact with the small rib, but there was no evidence that the separator was strongly pulled.

The lead storage batteries of Comparative Examples 1 to 3 have shorter life than the lead storage batteries of the conventional example. When the disassembly survey was performed at the end of the life, the lead storage battery of Comparative Example 1 was confirmed to be broken and short-circuited due to the oxidation deterioration of the separator. It is considered that this is because the main ribs are not provided and only the small ribs are provided, so that the distance between the positive electrode plate and the base portion of the separator is short, and the oxidative atmosphere around the positive electrode plate is likely to cause oxidative deterioration.

Regarding the lead storage batteries of Comparative Examples 2 and 3, the separator in the portion where the small ribs were formed was oxidatively deteriorated, which caused a short life. This is because although the lead storage batteries of Comparative Examples 2 and 3 have the main ribs, the range in which the main ribs are formed is narrow, and the area between the base portion of the separator and the positive electrode plate in the portion where the small ribs are formed is small. It is considered that the effect of suppressing the oxidative deterioration is small because it is difficult to maintain the proper distance.

The lead acid battery of Comparative Example 6 had a slightly longer life than the lead acid battery of the conventional example. When the lead storage battery of Comparative Example 6 was disassembled and examined at the same number of cycles as the life cycle of the conventional example, the positive electrode plate was warped to the same extent as the lead storage battery of the conventional example. Since a small rib was formed in the portion of the portion facing the end of the positive electrode plate, the separator was not pressed against the end of the positive electrode plate and did not break. However, the range in which the main ribs are formed is narrow, and the distance between the base portion of the separator and the positive electrode plate in the portion in which the small ribs are formed is difficult to maintain at an appropriate distance. Although not as good as that of a lead storage battery, oxidative deterioration of the surface of the separator proceeded.

The lead acid battery of Comparative Example 4 had a slightly longer life than the lead acid battery of the conventional example. When the lead storage battery of Comparative Example 4 was disassembled and examined at the same number of cycles as the life cycle of the conventional example, the bent positive electrode plate pressed the main rib of the separator, as in the lead storage battery of the conventional example. Was confirmed. However, unlike the lead-acid battery of the conventional example, it is the small rib that comes into contact with the end of the positive electrode plate with the largest amount of warpage, so the pressure acting on the separator becomes relatively weak, and the time until the separator breaks It is probable that the delay was delayed.

The lead storage batteries of Examples 4 and 5 had a slightly shorter life than the lead storage batteries of Examples 1 to 3, but had a longer life than the lead storage batteries of the conventional example. When the lead storage batteries of Examples 4 and 5 were dismantled and examined at the same number of cycles as the life cycle of the conventional example, similar to the lead storage batteries of Examples 1 to 3, the main ribs and the small ribs protruded. Due to the difference in height, there is a margin in the amount of bending of the positive electrode plate until the separator is pressed. Therefore, the edge of the positive electrode plate did not press the small rib, and the separator did not break.

However, the edge of the bent positive electrode plate was caught by the small rib, and the separator was started to be pulled. On the other hand, in the lead-acid batteries of Examples 1 to 3, the edge of the bent positive electrode plate was in contact with the small rib but was not caught. It is considered that, in the lead storage batteries of Examples 1 to 3, since the shape of the protruding tip of the small rib did not have a corner, the edge of the end of the positive electrode plate was hard to be caught by the small rib. It is considered that this was the cause of the difference in life between Examples 1 to 3 and Examples 4 and 5.

The lead acid battery of Comparative Example 5 had a slightly shorter life than the lead acid battery of the conventional example. When the lead storage battery of Comparative Example 5 was disassembled for the number of life cycles, it was found that the base portion of the separator was oxidatively deteriorated and broken. It is considered that this is because a small rib is not formed in a portion of the base portion of the separator that faces the end portion of the positive electrode plate, and thus the base portion of the separator and the end portion of the positive electrode plate are likely to come into contact with each other. For example, when the separator fluctuates due to the convection of the electrolytic solution or the flow of gas, the chances of the base portion of the separator and the end portion of the positive electrode plate contacting each other increase, and thus the separator is more likely to be oxidized and deteriorated than the lead storage battery of the conventional example.

[Second embodiment]
The structure of the lead storage battery according to the second embodiment of the present invention will be described in detail with reference to FIG. 17A is a plan view of a separator included in the lead storage battery according to the second embodiment, FIG. 17B is a view of the X arrow of FIG. 17A, and FIG. 17C is a Y arrow of FIG. It is a perspective view. Since the structure of the lead storage battery according to the second embodiment is almost the same as that of the lead storage battery according to the first embodiment, description of the same parts will be omitted and only different parts will be described.

As shown in (a) of FIG. 17, a plurality of small ribs 33 are formed side by side over the entire widthwise end portions 30b, 30b of the separator 30 on the surface of the base portion 31 facing the positive electrode plate 10. There is. In addition, as shown in FIG. 17A, a plurality of main ribs 32 are formed side by side on the entire central portion 30a in the lateral width direction of the separator 30 on the surface of the base portion 31 facing the positive electrode plate 10. There is. Then, as shown in FIG. 17A, the main ribs 32 adjacent to each other are smaller than the distance in the lateral width direction between the adjacent small ribs 33 (hereinafter, sometimes referred to as “pitch of the small ribs”). The distance in the lateral width direction (hereinafter, also referred to as “main rib pitch”) is formed to be larger.

The larger the main rib pitch is, the easier the electrolyte is to move vertically. Further, as the pitch of the small ribs is smaller, the separator 30 is less likely to bend, and thus the positive electrode plate 10 and the base portion 31 of the separator 30 are less likely to come into contact with each other. However, vertical movement of the electrolytic solution is less likely to occur. In order to make the separator 30 hard to bend, the smaller the pitch of the small ribs, the more preferable, and the smaller the thickness of the positive electrode plate 10 and the negative electrode plate 20 is.

Further, when the pitch of the small ribs and the pitch of the main ribs are as described above, even when the four corners of the positive electrode plate 10 are curved toward the separator 30 and the positive electrode plate 10 is deformed into a bowl shape, It is possible to prevent the four corners of the positive electrode plate 10 from pressing the small ribs 33 and tearing the base portion 31 of the separator 30.

In addition, in the lead storage battery according to the second embodiment, all the small ribs 33 adjacent to each other have the same distance in the horizontal width direction, but among the small ribs 33 formed at the end portions 30b in the horizontal width direction, the horizontal width direction. The small ribs 33 arranged on the center side of the and the small ribs 33 arranged on the outer edge side in the lateral width direction may have different lateral distances between the adjacent small ribs 33. When the distance of the small rib 33 on the outer edge side in the lateral width direction is made smaller than the distance of the small rib 33 on the center side in the lateral width direction, even if the four corners of the positive electrode plate 10 press the small rib 33, The base portion 31 is less likely to be torn.

Further, the protrusion height of the main rib 32 may be constant over the entire vertical direction of the separator 30, but may not be constant. For example, as shown in FIG. 17B, the main rib 32 may have a shape in which the central portion of the separator 30 in the vertical direction is high and both end portions of the separator 30 in the vertical direction are low. As shown in (b) of FIG. 17, if the shape of the protruding tip of the main rib 32 in the X arrow view is a shape along the positive electrode plate 10 that is deformed into a bowl shape, the deformed positive electrode plate 10 causes the main rib 32 to move. It can suppress being pressed.

Further, the protrusion heights of the main ribs 32 may be the same for all the main ribs 32, but may not be the same. For example, as shown in (c) of FIG. 17, among the plurality of main ribs 32, the main rib 32 disposed on the center side in the lateral width direction of the separator 30 has a high protruding height and the end portion in the lateral width direction of the separator 30. The main rib 32 disposed on the side may have a low protruding height. As shown in (c) of FIG. 17, if the protruding height of each main rib 32 is set along the positive electrode plate 10 deformed like a bowl, the deformed positive electrode plate 10 presses the main rib 32. Can be suppressed. Note that, in the Y arrow view, the shape of the line connecting the protruding tips of the plurality of main ribs 32 may be trapezoidal as shown in (c) of FIG. 17, but may be an ellipse, a quadratic curve, a hyperbola, or the like. It may be curved.

Further, the small ribs 33 may be formed on both end portions 30b, 30b in the lateral width direction of the separator 30, as shown in FIGS. It may be formed on only one of 30b. When formed on only one side, the lateral width direction end portion 30b where the small rib 33 is formed has a smaller distance from the uncut portion 12 than the distance from the collector ear 11 to the lateral width direction end portion 30b( That is, the end portion near the protrusion).

[Third embodiment]
The structure of the lead storage battery according to the third embodiment of the present invention will be described in detail with reference to FIG. FIG. 18 is a plan view of a separator included in the lead storage battery according to the third embodiment. Since the structure of the lead storage battery according to the third embodiment is almost the same as that of the lead storage battery according to the first embodiment, description of the same parts will be omitted and only different parts will be described.

In the lead storage battery according to the first and second embodiments, the small rib 33 has a linear shape that is continuous along the vertical direction of the separator 30, but in the lead storage battery according to the third embodiment, an ellipse, It has a curved shape such as a quadratic curve or a hyperbola. More specifically, as shown in FIG. 18, of the small ribs 33, the portions formed at the corners of the base portion 31 at positions diagonal to the current collecting ears 11 are arranged in the vertical direction of the separator 30. It has a linear shape that intersects and is continuous along the direction toward the corner.

With such a configuration, after the four corners of the positive electrode plate 10 are curved toward the separator 30 and the positive electrode plate 10 is deformed into a bowl shape and contacts the small rib 33, the four corners of the curved positive electrode plate 10 are Even if the positive electrode plate is deformed in the returning direction (that is, even if it is deformed in a direction approaching a flat plate), the direction in which the corner of the positive electrode plate 10 is deformed and the direction in which the small ribs 33 are continuous are substantially the same. The corners of 10 are unlikely to be caught by the small rib 33. Therefore, it is possible to prevent the corner portion of the positive electrode plate 10 from pressing the small rib 33 and tearing the base portion 31 of the separator 30.

Since the corners of the four corners of the positive electrode plate 10 that are diagonal to the current collecting ears 11 are most easily deformed, the corners of the base portion 31 of the small ribs 33 that are at least diagonal to the current collecting ears 11 are the most deformable. The portion formed in the portion is preferably curved as described above, but as shown in FIG. 18, the other three corners may also be curved.

The small rib 33 may have a curved shape as shown in FIG. 18, but the portion formed at the corner of the base portion 31 at a position diagonal to the current collecting ear 11 has a separator 30. It may have a linear shape as long as it has a linear shape that intersects with the vertical direction and is continuous along the direction toward the corner.
Further, when the small ribs 33 are curved, the center of curvature of the small ribs 33 is located on a straight line connecting the current collecting ears 11 and the corners of the base portion 31 at positions diagonal to the current collecting ears 11. It is preferable.

Furthermore, it is preferable that the center of curvature of the positive electrode plate 10 (that is, the apex of the convex surface of the positive electrode plate 10 that has been transformed into a bowl shape) be located below the center of the separator 30. With such a configuration, it can be said that the degree of curvature of the upper side portion of the separator 30 that is the outlet of gas bubbles of the gas in the up-down direction is small, so that the gas is unlikely to stay in the electrode plate group 1.

That is, if the degree of curvature of the portion above the center of the positive electrode plate 10 in the up-down direction, which is the outlet when gas bubbles are discharged to the outside from the electrode plate group 1, is small, the gas is in the electrode plate group 1. Since it does not easily stay inside and is easily discharged, an increase in internal resistance of the lead storage battery is suppressed. If the flatness of the upper part of the positive electrode plate 10 after the formation in the vertical direction is 4.0 mm or less, the effect of suppressing an increase in the internal resistance of the lead storage battery is achieved.

In the lead-acid batteries according to the first, second, and third embodiments, the small rib 33 is formed at the lateral width direction end of the separator 30 on the surface of the base portion 31 facing the positive electrode plate 10. Small vertical ribs 33 that are continuous along the vertical direction of the separator 30 may be formed on the vertical end portions of the separator 30 on the surface of the separator 31 that faces the positive electrode plate 10. When not only the warp in the width direction but also the warp in the vertical direction occurs in the positive electrode plate 10 (that is, when the positive electrode plate 10 is curved in a bowl shape), the separator 30 on the surface of the base portion 31 facing the positive electrode plate 10 is separated. If the small ribs 33 are also formed on the upper and lower ends, it is possible to prevent the positive electrode plate 10 from pressing the small ribs 33 and tearing the base portion 31 of the separator 30.

DESCRIPTION OF SYMBOLS 1 Electrode plate group 10 Positive electrode plate 11 Current collecting ear 12 Projection part 20 Negative electrode plate 30 Separator 30a Horizontal width direction central part 30b Horizontal width direction end part (end part near projection part, current collecting ear end part)
31 Base part 32 Main rib 33 Small rib

Claims (4)

A lead storage battery comprising a positive electrode plate and a negative electrode plate, wherein a plurality of electrode plates are alternately laminated via a separator,
On the upper edge portion of the positive electrode plate, a current collecting ear protruding upward of the positive electrode plate, and a protruding portion protruding upward of the positive electrode plate and having a protruding height lower than that of the current collecting ear, Formed at intervals in the width direction of the separator,
The separator is a film-shaped base portion, a plurality of main ribs protruding from a surface of the base portion facing the positive electrode plate and in contact with the positive electrode plate, and a plurality of main ribs protruding from a surface of the base portion facing the positive electrode plate. A plurality of small ribs having a lower protruding height than the ribs,
The main rib is formed in a continuous linear shape along the vertical direction of the separator, and is formed in the central portion in the lateral width direction of the separator on the surface of the base portion facing the positive electrode plate,
The small rib is formed in a lateral width direction end portion of the separator on the surface of the base portion facing the positive electrode plate in a continuous linear shape along the vertical direction of the separator. The widthwise end portion in which is formed is a widthwise end portion whose distance from the protruding portion is smaller than the distance from the current collecting ear,
A lead storage battery in which the main rib disposed on the end portion side in the lateral width direction of the main ribs is located above a portion of the base portion facing the protrusion. The lead storage battery according to claim 1, wherein the protruding tip of the small rib does not have a corner. Of the small ribs formed at the lateral width direction ends, the small ribs arranged on the center side in the lateral width direction and the small ribs arranged on the outer edge side in the lateral width direction are adjacent to each other. The distance between the ribs in the lateral width direction is different, and the distance of the small rib on the outer edge side in the lateral width direction is smaller than the distance of the small rib on the center side in the lateral width direction. Item 2. The lead acid battery according to item 2. Of the small ribs, a portion formed at a corner of the base portion at a position diagonal to the current collecting ear is along a direction that intersects with the vertical direction of the separator and goes to the corner. The lead storage battery according to claim 1, wherein the lead storage battery has a continuous linear shape.

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