CN211700412U

CN211700412U - Lead-acid battery

Info

Publication number: CN211700412U
Application number: CN201921870612.0U
Authority: CN
Inventors: 荻野由涼
Original assignee: Furukawa Battery Co Ltd
Current assignee: Furukawa Battery Co Ltd
Priority date: 2019-01-29
Filing date: 2019-11-01
Publication date: 2020-10-16
Anticipated expiration: 2029-11-01
Also published as: JP7053512B2; JP2020123447A

Abstract

The invention provides a lead storage battery with long service life and a separator which is not easy to damage even if external stress is received by a deformed positive plate. A current collecting lug part (11) and a protrusion part (12) having a lower protrusion height than the current collecting lug part (11) are formed on the upper edge part of the positive electrode plate (10). The partition (30) has a base (31); the positive electrode plate is provided with a plurality of main ribs (32) that protrude from the surface of the base (31) that faces the positive electrode plate (10) and that contact the positive electrode plate (10), and a plurality of small ribs (33) that protrude from the surface of the base (31) that faces the positive electrode plate (10) and that protrude at a height lower than that of the main ribs (32). The main rib (32) is formed at the widthwise central portion (30a) of the surface of the base (31) facing the positive electrode plate (10), and the small rib (33) is formed at the widthwise end portion (30b) of the surface of the base (31) facing the positive electrode plate (10). Of the main ribs (32), the main rib (32) disposed on the end side closest to the lateral width direction is located on the portion of the base (31) that faces the protrusion (12).

Description

Lead-acid battery

Technical Field

The present invention relates to a lead storage battery.

Background

Lead-acid batteries have a problem that a separator is broken to cause a short circuit and thereby shorten their life. As a main cause of the separator breakage, there are oxidative deterioration and external stress.

First, the oxidative deterioration will be described. The separator may be damaged by oxidation degradation 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 a rib on the surface of the separator is widely used.

Next, the external stress will be described. The separator may be damaged by external stress received from the deformed positive electrode plate. However, when the end of the positive electrode plate extends so as to be warped toward the separator, the end of the positive electrode plate strongly presses the surface of the separator. 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. When the warping and stretching of the positive electrode plate further progress in such a state, the surface of the separator is stretched by each rib, and therefore the separator having relatively low strength cannot follow the stretching due to the stretching, and is broken to be broken.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 3-149748

Disclosure of Invention

Technical problem to be solved by the invention

The invention provides a lead storage battery with long service life and a separator which is not easy to damage even if external stress is received by a deformed positive electrode plate.

Means for solving the problems

A lead-acid battery according to an aspect of the present invention includes an electrode group formed by alternately laminating a plurality of positive electrode plates and negative electrode plates with separators interposed therebetween, wherein a current collecting lug portion 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 lug portion are formed at an upper edge portion of the positive electrode plate with a space therebetween along a lateral width direction of the separator, and the separator includes: a film-like base; a plurality of main ribs protruding from a surface of the base portion facing the positive electrode plate and contacting the positive electrode plate; and a plurality of small ribs protruding from a surface of the base portion facing the positive electrode plate and having a protruding height lower than that of the main rib, the main rib having a linear shape continuous in a vertical direction of the separator, and is formed in a widthwise central portion of the separator on a surface of the base portion facing the positive electrode plate, the small rib portion being formed in a linear shape continuous in a vertical direction of the separator, and a transverse width direction end portion of the separator formed on a surface of the base portion facing the positive electrode plate, the transverse width direction end portion having the small rib portion formed thereon, a lateral width direction end portion having a smaller distance from the protruding portion than the current collecting lug portion, the main rib portion disposed on the end portion side closest to the lateral width direction among the main rib portions is located on a portion of the base portion facing the protruding portion.

Effects of the invention

The lead storage battery according to the present invention has a long life and is less likely to break the separator even when external stress is applied to the deformed positive electrode plate.

Drawings

Fig. 1 is a partial cross-sectional view illustrating the structure of a lead-acid battery according to a first embodiment of the present invention.

Fig. 2 is a diagram illustrating a substrate used for the positive electrode plate.

Fig. 3 is a view for explaining a connected sheet for manufacturing the substrate of fig. 2.

Fig. 4 is a diagram showing a structure of a main part of the electrode plate group included in the lead-acid battery of fig. 1.

Fig. 5 is a diagram showing the structure of the main part of the electrode plate group included in the lead-acid battery of example 2.

Fig. 6 is a diagram showing the structure of the main part of the electrode plate group included in the lead-acid battery of example 3.

Fig. 7 is a diagram showing the structure of the main part of the electrode plate group included in the lead-acid battery of example 4.

Fig. 8 is a diagram showing the structure of the main part of the electrode plate group included in the lead-acid battery of 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 a conventional example.

Fig. 10 is a diagram showing the structure of a main part of an electrode plate group included in the lead-acid battery of comparative example 1.

Fig. 11 is a diagram showing the structure of a main part of an electrode plate group included in the lead-acid battery of comparative example 2.

Fig. 12 is a diagram showing the structure of a main part of an electrode plate group included in the lead-acid battery of comparative example 3.

Fig. 13 is a diagram showing the structure of a main part of the electrode plate group included in the lead-acid battery of comparative example 4.

Fig. 14 is a diagram showing the structure of a main part of an electrode plate group included in the lead-acid battery of comparative example 5.

Fig. 15 is a diagram showing the structure of a main part of an electrode group included in the lead-acid battery of comparative example 6.

Fig. 16 is a graph showing the results of a life test of each lead-acid battery.

Fig. 17 is a diagram illustrating a structure of a separator included in a lead-acid battery according to a second embodiment of the present invention.

Fig. 18 is a diagram illustrating a structure of a separator included in a lead-acid battery according to a third embodiment of the present invention.

Detailed Description

An embodiment of the present invention will be explained. The embodiments described below are merely examples of the present invention, and the present invention is not limited to the embodiments. Various changes and improvements can be made to the present embodiment, and embodiments to which such changes and improvements are made are also included in the present invention.

[ first embodiment ]

The structure of a lead-acid battery according to a first embodiment of the present invention will be described in detail with reference to fig. 1. The lead-acid battery according to the first embodiment includes an electrode group 1 formed by alternately laminating a plurality of positive electrode plates 10 and negative electrode plates 20 with separators 30 interposed therebetween. The electrode group 1 is accommodated in an electrolyte solution not shown and a battery case 41 so that the lamination direction thereof 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 the battery case 41 is impregnated with the electrolyte solution.

The positive electrode plate 10 is formed by, for example, filling an opening of a plate-shaped lattice body made of a lead alloy with a positive electrode active material containing lead dioxide, and forming active material layers (shown by reference numeral 10a in fig. 4) made of the positive electrode active material containing lead dioxide on both plate surfaces of the plate-shaped lattice body made of the lead alloy. The negative electrode plate 20 is formed by, for example, filling an opening of a plate-shaped lattice body made of a lead alloy with a negative electrode active material containing metallic lead, and forming active material layers (shown by reference numeral 20a in fig. 4) made of the negative electrode active material containing metallic lead on both plate surfaces of the plate-shaped lattice body made of the lead alloy. The plate-shaped lattice bodies serving as the substrates of the positive electrode plate 10 and the negative electrode plate 20 can be manufactured by casting, punching (punching), or spreading. The separator 30 is a porous film body made of, for example, resin, glass, or the like. The planar shapes of positive electrode plate 10, negative electrode plate 20, and separator 30 are, for example, rectangular.

A current collecting lug 11 protruding upward (upward in fig. 1) of the positive electrode plate 10 is formed at an upper edge portion of the positive electrode plate 10 (substrate) (i.e., an edge portion located on the upper side of an edge portion of the positive electrode plate 10), and a current collecting lug 21 protruding upward (upward in fig. 1) of the negative electrode plate 20 is formed at an upper edge portion of the negative electrode plate 20. The current collecting lug portions 11 of the positive electrode plates 10 are connected by positive electrode tabs 13, and the current collecting lug portions 21 of the negative electrode plates 20 are connected by negative electrode tabs 23. The positive electrode tab 13 is connected to one end of the positive electrode terminal 15, the negative electrode tab 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 penetrate the lid 43 that closes the opening of the battery case 41 and are exposed to the outside of the case of the lead acid battery constituted by the battery case 41 and the lid 43.

As shown in fig. 2, the projecting portion 12 projecting upward of the positive electrode plate 10 and having a lower projecting height than the current collecting lug portion 11 is formed at the upper edge portion of the positive electrode plate 10 (substrate) at an interval in the lateral width direction of the separator 30 with respect to the current collecting lug portion 11 of the positive electrode plate 10 (in fig. 1 and 2 (b), the front-rear direction with respect to the paper surface, and the left-right direction in fig. 2 (a) — hereinafter, sometimes referred to simply as the "lateral width direction"). The projecting portion 12 may be formed on the upper edge portion of the negative electrode plate 20 in the same manner as the positive electrode plate 10, or the projecting portion 12 may not be formed.

Examples of the protruding portion 12 include a cut-out portion generated when manufacturing a plate-shaped lattice body as a substrate of the positive electrode plate 10. The method of manufacturing the plate-like lattice body and the cut-away portion will be described in detail with reference to fig. 2 and 3. In the case of producing a plate-shaped lattice body by the die cutting method, a rolled sheet of a lead alloy is first die-cut to produce a connected sheet 100 in which a plurality of plate-shaped lattice bodies are connected, and then the connected sheet 100 is cut to obtain a plate-shaped lattice body.

An example of the connected sheet 100 is shown in fig. 3. Fig. 3 is a plan view of the connected body sheet 100 to which six plate-like lattice bodies are connected. The connected sheet 100 of fig. 3 has the following configuration. That is, the upper edges of the two plate-like lattice bodies are connected to each other by two connecting portions 11a serving as portions of the current collecting lugs 11, and three of the connecting portions are arranged and the side edges are connected to each other, thereby forming the connected body sheet 100 shown in fig. 3.

When the connected body sheet 100 of fig. 3 is cut with a cutter or the like, the end of the connecting portion 11a and the side edge of the plate-like lattice body are cut to form six plate-like lattice bodies. At this time, when the connecting portions 11a are cut, in order to form the current collecting lug portions 11 on the plate-shaped lattices obtained by cutting, the end portions on different sides are cut with respect to the two connecting portions 11a connecting the two plate-shaped lattices.

It is preferable to cut the coupling portion 11a along the boundary between the coupling portion 11a and the upper edge portion of the plate-like lattice body so as not to generate a cut-away portion when cutting the coupling portion 11a, but it is preferable to cut the coupling portion 11a by providing a cutting amount so as to surely avoid damage to the upper edge portion of the plate-like lattice body at the time of cutting. As a result, a cut portion remains at the upper edge of the plate-like lattice body. The protruding height from the upper edge of the cut-away portion is not particularly limited, but is, for example, 1mm or more and 3mm or less.

The type of cutting tool used for cutting the connection portion 11a is not particularly limited, but a tool such as a rotary cutter can be used. The shape of the protruding tip of the cutting margin (protruding portion 12) is also controlled depending on the shape of the blade of the cutter and the cutting method. For example, if cutting is performed using a rotary cutter, the cutting is started by bringing the blade into contact with one surface of the coupling portion 11a, and the blade is engaged with the other surface of the coupling portion 11a, but the protruding height from the upper edge of the cutting margin portion is different between the surface of the one surface into which the root of the blade is engaged and the surface of the other surface to which only the cutting edge can reach. That is, as shown in fig. 2 b, the protruding tip of the cutout portion (protruding portion 12) has a shape having a higher protruding height from the upper edge of the cutout portion than the one surface side (left side in fig. 2 b), and the other surface side (right side in fig. 2 b).

As shown in fig. 4, the separator 30 has: a film-like base 31; a plurality of main ribs 32 protruding from a surface of base 31 facing positive electrode plate 10 and contacting positive electrode plate 10; and a plurality of small ribs 33 protruding from the surface of base 31 facing positive electrode plate 10 and having a height lower than that of main ribs 32. The small ribs 33 do not contact the positive electrode plate 10 in a state where the positive electrode plate 10 is not deformed or a state where the deformation of the positive electrode plate 10 is small.

The main rib 32 is formed in a linear shape continuous in the vertical direction of the separator 30, and is formed in the widthwise central portion 30a of the separator 30 on the surface of the base 31 facing the positive electrode plate 10.

The small rib 33 is formed in a linear shape continuous in the vertical direction of the separator 30, and is formed at the lateral end 30b of the separator 30 on the surface of the base 31 facing the positive electrode plate 10. The widthwise end 30b on which the small rib 33 is formed is the widthwise end 30b which is located at the position separated from the widthwise central portion 30a and which is located at the smaller distance from the protruding portion 12 than the distance from the current collecting lug 11, out of the two widthwise ends 30b, 30 b.

The main rib 32 is formed at the lateral end 30b that is located at a smaller distance from the current collecting ear 11 than the protrusion 12, but a small rib 33 may be formed instead of the main rib 32. That is, the separator 30 may have: the widthwise central portion 30a formed with the main rib 32 is sandwiched between the widthwise

opposite end portions

30b, 30b formed with the small rib 33.

Note that, although two widthwise end portions 30b are present at the base portion 31 of the separator 30, hereinafter, the one widthwise end portion 30b (the right end portion 30b in fig. 4) having a smaller distance from the projecting portion 12 than the distance from the current collecting lug 11 is referred to as a "projecting portion offset end portion", and the one widthwise end portion 30b (the left end portion 30b in fig. 4) having a smaller distance from the current collecting lug 11 than the distance from the projecting portion 12 is referred to as a "current collecting offset end portion". Similarly, the side (the right side in fig. 4) having a smaller distance from the projecting portion 12 than the distance from the current collecting lug 11 in the lateral width direction is referred to as "projecting portion offset end portion side", and the side (the left side in fig. 4) having a smaller distance from the current collecting lug 11 than the distance from the projecting portion 12 is referred to as "current collecting lug offset end portion side".

In the lead-acid battery according to the first embodiment as described above, the main rib 32 disposed on the end portion side closest to the lateral width direction among the main ribs 32 is positioned on the portion of the base portion 31 that faces the protruding portion 12 (see fig. 4). In other words, a boundary line B between the widthwise central portion 30a where the main rib 32 is formed and the widthwise end portion 30B where the small rib 33 is formed is located above a portion of the base portion 31 facing the protruding portion 12. The "end portion side in the lateral direction" means the end portion side in the lateral direction having a smaller distance from the protruding portion 12 than the distance from the current collecting lug 11, that is, the protruding portion offset end portion side.

With this configuration, the lead-acid battery according to the first embodiment is less likely to break and has a long life even when the external stress is applied to the deformed positive electrode plate 10. Thus, the lead acid battery according to the first embodiment is preferably mounted on a vehicle, for example, and used as a power source for starting an internal combustion engine of the vehicle. The lead-acid battery according to the first embodiment is preferably used in a high-temperature environment. The lead-acid battery according to the first embodiment can be used not only for a power source for starting an internal combustion engine of a vehicle, but also as a power source for an electric vehicle, an electric forklift, an electric bus, an electric bicycle, an electric motorcycle, a small electric scooter, a golf cart, an electric motorcycle, or the like. The lead-acid battery according to the present embodiment can also be used as a lighting power source or a backup power source. Or as an electric energy storage device for electric energy generated by solar power generation, wind power generation, or the like.

The operational effects of the lead-acid battery according to the first embodiment will be described in detail below. When the positive electrode plate 10 is oxidized, the end of the positive electrode plate 10 may extend to be warped toward the separator 30, and the end of the positive electrode plate 10 may strongly press the surface of the separator 30. At this time, when the main rib 32 having a high protruding height is formed on the portion of the surface of the separator 30 facing the end of the positive electrode plate 10, the end of the positive electrode plate 10 strongly presses the main rib 32 on the surface of the separator 30. When the warpage and elongation of the positive electrode plate 10 further progress in such a state, the surface of the separator 30 is stretched by each main rib 32, and therefore the separator 30 having relatively weak strength cannot follow the elongation due to the stretching and is broken.

However, in the lead-acid battery according to the first embodiment, the small ribs 33 having a low projecting height are formed in the portions of the surface of the separator 30 that face the ends of the positive electrode plate 10, and therefore even if the deformed ends of the positive electrode plate 10 contact the small ribs 33, the pressing of the separator 30 by the ends of the positive electrode plate 10 can be suppressed. Therefore, the lead acid battery according to the first embodiment has a long life and the separator 30 is less likely to be damaged.

The warpage and extension of the end of the positive electrode plate 10 increase from the cutout, and the warpage and extension of the portion located on the end side in the lateral width direction from the cutout are large. When the cut-off portion is not present, the warpage and extension of the end portion of the positive electrode plate 10 become smaller as compared with the case where the cut-off portion is present. Even if the current collecting lug 11 is present, the warping and extension of the end of the positive electrode plate 10 do not increase.

According to the study of the present inventors, it was found that this is caused by the shape of the protruding tip of the cut-away portion (protruding portion 12). That is, as shown in fig. 2 (b), when the protruding tip of the cutout portion (protruding portion 12) has a shape in which the protruding height from the upper edge portion of the cutout portion is higher on the other surface side than on the one surface side, a difference occurs in the amount of corrosion and the stress distribution (for example, distribution of tensile stress) on both surface sides. Therefore, it is conceivable that the end of the positive electrode plate 10 is warped toward the other surface side having a high projecting height, and the portion on the end side in the lateral width direction of the cutout portion is warped and extended more largely.

Accordingly, if the widthwise position of the boundary line B between the widthwise central portion 30a where the main rib 32 is formed and the widthwise end portion 30B where the small rib 33 is formed is set with respect to the cut-away portion, the small rib 33 can be formed at an appropriate position, and therefore, a lead acid battery having a long life and a separator 30 that is not easily broken can be easily and reliably designed.

The protruding height of the small rib 33 is not particularly limited if it is lower than the protruding height of the main rib 32, but the protruding height is preferably 25% to 75% of the protruding height of the main rib 32, and more preferably 45% to 65%.

The shape of the projecting tip of each small rib 33 is not particularly limited, and the cross-sectional shape of the projecting tip when the small rib 33 is cut along a plane orthogonal to the vertical direction of the separator 30 may be a polygon such as a triangle, a rectangle, a trapezoid, or a pentagon, but preferably the projecting tip does not have a corner. That is, the protruding distal end of the small rib portion 33 preferably has a rounded smooth shape, and the cross-sectional shape of the protruding distal end when the small rib portion 33 is cut along a plane orthogonal to the vertical direction of the separator 30 is preferably, for example, a semicircular shape or a semi-elliptical shape.

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, a state in which the positive electrode plate 10 or the negative electrode plate 20 is sandwiched by bending a film-like material into a U-shape, or a film shape in which the positive electrode plate 10 or the negative electrode plate 20 is sandwiched by a plurality of members. The electrode plate housed inside the bag-shaped separator 30 may be either the positive electrode plate 10 or the negative electrode plate 20, but the effect of suppressing breakage of the separator 30 is further enhanced by the manner in which the negative electrode plate 20 is housed.

The composition of the electrolyte is not particularly limited, and a general electrolyte used in a lead-acid battery can be applied without any problem. In order to improve the charge acceptance of the lead-acid battery, it is preferable that the electrolyte contains aluminum ions, and the content of the aluminum ions in the electrolyte is preferably 0.01 mol/L or more. However, when the content of aluminum ions in the electrolytic solution is high, the gas is not easily discharged from the electrode plate group 1 to the outside, and therefore the content of aluminum ions in the electrolytic solution is preferably 0.3 mol/L or less.

The electrolyte may contain sodium ions. The content of sodium ions in the electrolyte solution can be set to 0.002 mol/L or more and 0.05 mol/L or less.

[ example of the first embodiment ]

The present invention will be described in more detail below with reference to examples and comparative examples.

(example 1)

The lead-acid battery of example 1 has the same structure as the lead-acid battery shown in fig. 1 and 4. The method for manufacturing the lead-acid battery of example 1 is explained below.

First, lead powder, water, dilute sulfuric acid, and short fibers are mixed to produce a positive electrode paste. Next, the rolled sheet of the calcium-based lead alloy was punched to produce a connected sheet 100 in which six sheet-like lattice bodies were connected as shown in fig. 3. Then, the positive electrode paste was filled into the openings of the plate-like lattice body of the connected sheet 100, and the connected sheet was cut with a rotary cutter, thereby obtaining six positive electrode filling plates.

The plate-shaped lattice body is in the shape of a rectangular plate with the vertical length of 110mm, the transverse width of 100mm and the thickness of 1.0 mm. A current collecting lug part 11 having a width of 10mm is formed on the upper edge of the plate-like lattice body. The position in the lateral width direction of the current collecting lug part 11 formed at the upper edge part of the plate-like lattice body is such that the distance in the lateral width direction between the side edge part of one of both side edge parts (vertical frames) of the plate-like lattice body which is close to the current collecting lug part 11 and the center of the current collecting lug part 11 is 33 mm. The projected height of the current collecting lug part 11 from the upper edge part was set to 17mm as the design center value, and the tolerance during cutting was set to ± 1 mm.

Further, a cut-away portion 12 having a width of 10mm is formed at the upper edge portion of the plate-like lattice body. The transverse width direction position where the cut-away portion 12 is formed at the upper edge portion of the plate-like lattice body is a position where the transverse width direction distance between the side edge portion of one of the both side edge portions (vertical frames) of the plate-like lattice body which is far from the current collecting lug portion 11 and the center of the cut-away portion 12 is 33 mm. The protruding height of the cut-away portion 12 from the upper edge portion is set to be 1mm to 3mm so as not to damage the upper edge portion of the plate-like lattice body when the connected sheet 100 is cut.

The positive electrode filled sheet thus obtained was cured and dried by a conventional method, to obtain a positive electrode cured sheet.

The plate-like lattice body for the negative electrode plate is produced by a continuous casting method. Then, the negative electrode paste is filled into the openings of the plate-like lattice body, and then cured and dried by a conventional method to obtain a negative electrode cured plate.

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

The protruding tip of each small rib 33 has a rounded shape without a corner. Further, a plurality of small ribs 33 are formed in a row at intervals of 0.5mm over the entire projecting portion offset end portion 30b (the lateral width direction end portion 30b having a smaller distance from the cutout portion 12 than the distance from the current collecting lug 11) of the separator 30 on the surface of the base portion 31 facing the positive electrode plate 10. That is, the small ribs 33 are formed at intervals of 0.5mm in the portion between the side edge of the separator 30 and the boundary line B described later. Further, a plurality of main ribs 32 are formed at 5mm intervals in line over the entire widthwise central portion 30a (i.e., the portion where the small ribs 33 are not formed) of the separator 30 on the surface of the base 31 facing the positive electrode plate 10.

Of the main ribs 32, the main rib 32 disposed on the end side closest to the lateral width direction (the lateral width direction end side where the distance from the cutout 12 is smaller than the distance from the current collecting lug 11, that is, the protrusion offset end side) is located on the portion of the base portion 31 facing the cutout 12. That is, a boundary line B between the widthwise central portion 30a where the main rib 32 is formed and the widthwise end portion 30B (the projecting portion offset end portion 30B) where the small rib 33 is formed is located above a portion of the base portion 31 that faces the cut-away portion 12. In addition, the main rib 32 disposed on the most projecting portion offset end side out of the main ribs 32 is located in the vicinity of the widthwise center of the portion of the base portion 31 opposed to the cutout portion 12.

A plurality of the positive electrode aging plates and the negative electrode aging plates are alternately laminated with the separators 30 interposed therebetween, thereby manufacturing the electrode plate assembly 1. In this example, six positive electrode aging plates and seven negative electrode aging plates were used. At this time, one negative-electrode matured plate is accommodated inside the bag-shaped separator 30, and the main rib 32 and the small rib 33 of the separator 30 are opposed to the positive-electrode matured plate with the two positive-electrode matured plates interposed therebetween.

Then, the electrode plate group 1 is accommodated in the battery case 41, and the gasket is adjusted so that the assembly pressure is 5 to 10kPa, thereby assembling the lead acid battery having a voltage of 2V. Next, an electrolyte was injected into the battery case 41, and chemical conversion was performed by a conventional method to obtain a lead-acid battery of example 1. The positive electrode cured sheet and the negative electrode cured sheet are converted into the positive electrode plate 10 and the negative electrode plate 20 by chemical conversion.

(example 2)

Fig. 5 shows a main part of a plate group 1 included in a lead-acid battery according to example 2. The present embodiment is completely the same as embodiment 1 except that the main rib 32 disposed on the most projecting portion offset end side of the main rib 32 is located on the most projecting portion offset end side of the portion of the base portion 31 opposed to the cutout portion 12, and therefore, other descriptions are omitted.

(example 3)

Fig. 6 shows a main part of a plate group 1 included in a lead-acid battery according to example 3. The present embodiment is completely the same as embodiment 1 except that the main rib 32 disposed on the most projecting portion offset end portion side of the main rib 32 is located on the most lug portion offset end portion side of the portion of the base portion 31 opposed to the cutout portion 12, and therefore, other descriptions are omitted.

(example 4)

Fig. 7 shows a main part of a plate group 1 included in a lead-acid battery according to example 4. The present invention is completely the same as example 1 except that the cross-sectional shape of the protruding tip when the small rib 33 is cut by a plane orthogonal to the vertical direction of the separator 30 is not semicircular but rectangular, and has a corner, and therefore, the other explanation is omitted.

(example 5)

Fig. 8 shows a main part of a plate group 1 included in a lead-acid battery according to example 5. The present invention is completely the same as example 1 except that the cross-sectional shape of the protruding tip when the small rib 33 is cut by a plane orthogonal to the vertical direction of the separator 30 is not semicircular but triangular, and has a corner, and therefore, the other explanation is omitted.

(former example)

Fig. 9 shows a main part of a plate group 1 included in a lead-acid battery of a conventional example. The present invention is completely the same as example 1 except that only the main rib 32 is formed on the surface of the base 31 facing the positive electrode plate 10, and the small rib is not formed, and therefore, the description thereof is omitted.

Comparative example 1

Fig. 10 shows a main part of an electrode plate group 1 included in a lead-acid battery of comparative example 1. The present invention is completely the same as in example 1 except that only the small ribs 33 are formed on the surface of the base 31 facing the positive electrode plate 10, and the main ribs 32 are not formed, and therefore, the description thereof is omitted.

Comparative example 2

Fig. 11 shows a main part of the electrode plate group 1 included in the lead-acid battery of comparative example 2. The present embodiment is completely the same as embodiment 1 except that the main rib 32 disposed at the most projecting portion offset end side of the main rib 32 is located at a portion of the base portion 31 facing the current collecting ear portion 11, and therefore, other descriptions are omitted.

Comparative example 3

Fig. 12 shows a main part of the electrode plate group 1 included in the lead-acid battery of comparative example 3. The present embodiment is completely the same as embodiment 1 except that the main rib 32 disposed on the most projecting portion offset end side of the main rib 32 is located at the position in the lateral width direction between the portion of the base portion 31 facing the current collecting ear portion 11 and the portion facing the cutout portion 12, and therefore, the other description is omitted.

Comparative example 4

Fig. 13 shows a main part of the electrode plate group 1 included in the lead-acid battery of comparative example 4. The present embodiment is completely the same as embodiment 1 except that the main rib 32 disposed on the most projecting portion offset end side of the main rib 32 is located on the most projecting portion offset end side of the portion of the base 31 facing the positive electrode plate 10, and therefore, the description thereof is omitted. As shown in fig. 13, the small ribs 33 are not formed in the portion of the base 31 facing the positive electrode plate 10, and the small ribs 33 are formed only on the projecting portion offset end side with respect to the portion of the base 31 facing the positive electrode plate 10.

Comparative example 5

Fig. 14 shows a main part of the electrode plate group 1 included in the lead-acid battery of comparative example 5. The present invention is completely the same as in embodiment 1 except that no small rib is formed on the projecting portion offset end portion 30b of the separator 30, and only the main rib 32 is formed on the base portion 31, and therefore, the other description is omitted.

Comparative example 6

Fig. 15 shows a main part of the electrode plate group 1 included in the lead-acid battery of comparative example 6. The present embodiment is exactly the same as embodiment 1, except that the main rib 32 on the most projecting portion offset end portion side of the main rib 32 is located at a position in the lateral width direction between a portion of the base portion 31 facing the current collecting ear portion 11 and a portion facing the cutout portion 12. Further, as compared with comparative example 3, the main rib 32 disposed on the most projecting portion offset end portion side among the main ribs 32 is located at a position in the lateral width direction closer to the cut-away portion 12. Other points are not different from each other, and therefore, other descriptions are omitted.

These lead-acid batteries were subjected to a life test by a method similar to the light load life test defined in JIS D5301. The method for testing the lifetime will be described in detail below.

The lead storage battery was discharged at 25A for 2 minutes under an atmosphere of 75 ℃ and charging at 14.8V (maximum current 25A) was continued for 10 minutes. Such a process is set as one cycle, and the cycle is repeated 480 times. Then, at the end of each cycle, the lead-acid battery was left at 25 ℃ for 56 hours, and after the left, continuous discharge was carried out at 280A for 5 seconds, and the voltage at the 5 th second of discharge was measured. While the cycle was repeated 480 times, if the discharge voltage discharged for the 5 th second decreased to 7.2V, it was determined that the life was reached, and the number of cycles up to this point was taken as the number of life cycles.

In the life test, the amount of water in the electrolyte was reduced, and therefore purified water was appropriately supplied to the lead-acid battery. Further, the lead storage battery of type 1 was subjected to a life test on two lead storage batteries, a disintegration test was performed on one lead storage battery after the test was continued until the life was reached, and a disintegration test was performed on the other lead storage battery after the test was continued until the number of life cycles of the lead storage battery of the conventional example. When the life of the lead-acid battery is shorter than that of the lead-acid battery of the conventional example, the disassembly test is directly performed.

The results of the life test are shown in the graph of fig. 16. The numerical value of the number of life cycles in the graph of fig. 16 is represented by a relative value when the number of life cycles of the conventional example is 100.

As is apparent from the graph of fig. 16, the lead-acid batteries of examples 1 to 3 have a longer life than the lead-acid batteries of the conventional examples and comparative examples 1 to 6.

In the lead-acid batteries of examples 1 to 3, after the cycle number of the lead-acid batteries was checked to be the same as the cycle number of the conventional example, the lead-acid batteries of examples 1 to 3 and the conventional example were subjected to the physical examination, and in particular, portions from the cut-off portions to the projecting portion offset end portions of the positive electrode plate (hereinafter referred to as "end portions of the positive electrode plate") were largely warped. In the lead-acid battery of the conventional example, the end portion of the extended and warped positive electrode plate presses and stretches the main rib portion of the separator, and the separator is broken and short-circuited.

In contrast, in the lead-acid batteries of examples 1 to 3, the amount of warpage of the positive electrode plate until the separator is pressed is greater than the difference in the protrusion heights of the main ribs and the small ribs, and therefore, the separator is not damaged and no short circuit is observed in comparison in the same cycle number. Further, the end of the warped positive electrode plate was in contact with the small rib, but there was no sign that the separator was strongly stretched.

The lead-acid batteries of comparative examples 1 to 3 have shorter lives than those of the conventional lead-acid batteries. When the disintegration test was performed at the time point of the end of life, damage or short circuit due to oxidation deterioration of the separator was confirmed in the lead-acid battery of comparative example 1. This is presumably because the distance between the positive electrode plate and the base portion of the separator is close to each other and oxidation deterioration is likely to occur due to the oxidizing atmosphere around the positive electrode plate because the main rib is not provided and only the small rib is provided.

In the lead-acid batteries of comparative examples 2 and 3, the separator in the portion where the bead was formed was oxidized and deteriorated, which caused a short life. It is considered that the lead-acid batteries of comparative examples 2 and 3 have the main rib, but the range in which the main rib is formed is narrow, and the distance between the base of the separator and the positive electrode plate in the portion in which the small rib is formed is difficult to maintain an appropriate distance, and therefore the effect of suppressing the oxidation degradation is small.

The lead-acid battery of comparative example 6 has a slightly longer life than the lead-acid battery of the conventional example. In the lead-acid battery of comparative example 6, after the disintegration test was performed with the same number of cycles of life as in the conventional example, the positive electrode plate was warped to the same extent as in the lead-acid battery of the conventional example, but the separator was not pressed by the end of the positive electrode plate and was not broken because the small rib portion was formed at the portion of the base portion of the separator facing the end of the positive electrode plate. However, since the range in which the main ribs are formed is narrow and it is difficult to maintain an appropriate distance between the base of the separator and the positive electrode plate in the portion in which the small ribs are formed, the oxidation degradation of the surface of the separator progresses, although this is less severe than the lead-acid batteries of comparative examples 2 and 3.

The lead-acid battery of comparative example 4 has a slightly longer life than the lead-acid battery of the conventional example. In the lead-acid battery of comparative example 4, after the body check was performed with the same cycle number as the cycle number of the conventional example, the main rib portion of the positive electrode plate pressing separator was confirmed to be warped in the same manner as the lead-acid battery of the conventional example. However, unlike the lead-acid battery of the conventional example, since the small rib portion abuts against the end portion of the positive electrode plate having the largest amount of warpage, it is considered that the pressing force acting on the separator is relatively weak, and the time until the separator is broken can be slightly delayed.

The lead-acid batteries of examples 4 and 5 have a slightly shorter life than the lead-acid batteries of examples 1 to 3, but have a longer life than the lead-acid batteries of the conventional examples. In the lead-acid batteries of examples 4 and 5, after the physical examination was performed with the same number of cycles as the number of life cycles of the conventional example, similarly to the lead-acid batteries of examples 1 to 3, the amount of warpage of the positive electrode plate until the separator was pressed was increased by the difference between the protrusion heights of the main ribs and the small ribs, and therefore the small ribs were not pressed by the end of the positive electrode plate, and the separator was not damaged.

However, the edge of the end of the warped positive electrode plate is pulled by the small rib, and the separator starts to be pulled. On the other hand, in the lead-acid batteries of examples 1 to 3, the edge of the end of the warped positive electrode plate was not pulled, though it was in contact with the small rib. This is considered to be because in the lead-acid batteries of examples 1 to 3, since the protruding tips of the small ribs have a shape without corners, the edge of the end of the positive electrode plate is less likely to be pulled by the small ribs, which is considered to be a cause of the difference in life span between examples 1 to 3 and examples 4 and 5.

The lead-acid battery of comparative example 5 has a slightly shorter life than the lead-acid battery of the conventional example. In the lead-acid battery of comparative example 5, after the cycle number of the lead-acid battery was examined by the cycle number, the oxidation deterioration of the base portion of the separator progressed, and no breakage occurred. This is presumably because the small rib is not formed in the portion of the base portion of the separator that faces the end portion of the positive electrode plate, and therefore the base portion of the separator and the end portion of the positive electrode plate are less likely to come into contact with each other. For example, when the separator swings due to convection of the electrolyte or flow of gas, the base of the separator and the end of the positive electrode plate are more likely to come into contact with each other, and therefore, oxidation degradation of the separator is less likely to progress as compared with the lead storage battery of the conventional example.

[ second embodiment ]

The structure of a lead-acid battery according to a second embodiment of the present invention will be described in detail with reference to fig. 17. Fig. 17 (a) is a plan view of a separator included in the lead-acid battery according to the second embodiment, (b) is an X-direction view of (a), and (c) is a Y-direction view of (a). The lead-acid battery according to the second embodiment has substantially the same structure as the lead-acid battery according to the first embodiment, and therefore, descriptions of the same portions will be omitted, and only different portions will be described.

As shown in fig. 17 (a), a plurality of small ribs 33 are formed in a row over the entire width-direction both

end portions

30b, 30b of the separator 30 on the surface of the base portion 31 facing the positive electrode plate 10. As shown in fig. 17 (a), the plurality of main ribs 32 are formed in a row over the entire widthwise central portion 30a of the separator 30 on the surface of the base 31 facing the positive electrode plate 10. As shown in fig. 17 (a), one of the lateral distances between adjacent main rib portions 32 (hereinafter, referred to as "main rib pitch") is formed larger than the lateral distance between adjacent small rib portions 33 (hereinafter, referred to as "small rib pitch").

The larger the pitch of the main rib, the more likely the electrolyte moves up and down. Further, the separator 30 is less likely to bend as the pitch of the small ribs decreases, and therefore contact between the positive electrode plate 10 and the base 31 of the separator 30 is less likely to occur. However, the up-and-down movement of the electrolyte is not easily generated. Since separator 30 is less likely to bend, the smaller the pitch of the small ribs is, the better, and the smaller the thickness of positive electrode plate 10 and negative electrode plate 20 is.

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

In the lead-acid battery according to the second embodiment, the lateral distances between the adjacent small rib portions 33 are all the same, but the lateral distances between the adjacent small rib portions 33 may be different between the small rib portion 33 disposed on the center side in the lateral direction and the small rib portions 33 disposed on the outer edge side in the lateral direction, among the small rib portions 33 formed at the lateral end 30 b. When one of the distances of the small ribs 33 on the outer edge side in the lateral width direction is smaller than the distance of the small rib 33 on the central side in the lateral width direction, the base portion 31 of the separator 30 is less likely to be torn even if the four corners of the positive electrode plate 10 press the small ribs 33.

The protrusion height of the main rib 32 may be constant across the entire separator 30 in the vertical direction, but may not be constant. For example, as shown in fig. 17 (b), the main rib 32 may have a shape in which the center in the vertical direction of the separator 30 is high and the both ends in the vertical direction of the separator 30 are low. As shown in fig. 17 (b), if the shape of the protruding tip of main rib 32 in the X-direction view is made to follow the shape of positive electrode plate 10 deformed into a bowl shape, main rib 32 can be prevented from being pressed by deformed positive electrode plate 10.

The protrusion height of the main rib 32 may be the same for all the main ribs 32, but may be different. For example, as shown in fig. 17 (c), of the plurality of main ribs 32, the main rib 32 disposed on the center side in the lateral width direction of the separator 30 may have a high protrusion height, and the main rib 32 disposed on the end side in the lateral width direction of the separator 30 may have a low protrusion height. As shown in fig. 17 (c), if the protrusion height of each main rib 32 is set so as to extend along positive electrode plate 10 deformed into a bowl shape, main rib 32 can be prevented from being pressed by positive electrode plate 10 after deformation. The line connecting the projecting tips of the plurality of main ribs 32 may have a trapezoidal shape as shown in fig. 17 (c) in the Y-direction view, but may have a curved shape such as an ellipse, a quadratic curve, or a hyperbola.

As shown in fig. 17 (a) and (c), the small ribs 33 may be formed on both the

ends

30b and 30b of the separator 30 in the lateral direction, but may be formed only on one of the

ends

30b and 30b of the separator 30 in the lateral direction. When the tab is formed only on one side, the lateral end 30b on which the small rib 33 is formed is the lateral end 30b (i.e., the protruding portion offset end) that is closer to the cutout portion 12 than the current collecting ear 11.

[ third embodiment ]

The structure of a lead-acid battery according to a third embodiment of the present invention will be described in detail with reference to fig. 18. Fig. 18 is a plan view of a separator included in the lead-acid battery according to the third embodiment. The lead-acid battery according to the third embodiment has substantially the same structure as the lead-acid battery according to the first embodiment, and therefore, descriptions of the same portions will be omitted, and only different portions will be described.

In the lead-acid battery according to the first and second embodiments, the small ribs 33 are linear and continuous along the vertical direction of the separator 30, but in the lead-acid battery according to the third embodiment, they are curved such as an ellipse, a quadratic curve, and a hyperbola. Specifically, as shown in fig. 18, the portions of the small ribs 33 formed at the corner portions of the base portion 31 at the positions diagonal to the current collecting ears 11 intersect with the vertical direction of the separator 30 and are continuous in the direction toward the corner portions.

With this configuration, even if the four corners of the positive electrode plate 10 after bending are deformed in the direction of the return direction (i.e., even if the four corners of the positive electrode plate 10 after bending are deformed in the direction approaching the flat plate shape) after the four corners of the positive electrode plate 10 are bent toward the separators 30 and the positive electrode plate 10 is deformed in the bowl shape and brought into contact with the small ribs 33, the direction in which the corner portions of the positive electrode plate 10 are deformed is substantially the same as the direction in which the small ribs 33 are continuous, and therefore the corner portions of the positive electrode plate 10 are less likely. Therefore, the corner portions of the positive electrode plate 10 can be prevented from pressing the small ribs 33 and tearing the base 31 of the separator 30.

Since the corner portions at the positions diagonal to the current collecting lug part 11 of the four corners of the positive electrode plate 10 are most easily deformed, at least the portion of the small rib part 33 formed at the corner portion of the base part 31 at the position diagonal to the current collecting lug part 11 is preferably curved as described above, and as shown in fig. 18, the other three corner portions may be similarly curved.

The small rib 33 may be curved as shown in fig. 18, but may be linear if the portion of the corner portion of the base portion 31 formed at a position diagonal to the current collecting ear portion 11 intersects the vertical direction of the separator 30 and is continuous in the direction toward the corner portion.

When the small rib 33 is curved, the center of curvature of the small rib 33 is preferably located on a straight line connecting the current collecting ear 11 and a corner of the base 31 located diagonally thereto.

Further, the center of curvature of positive electrode plate 10 (i.e., the apex of the convex surface of positive electrode plate 10 deformed into a bowl shape) is preferably located below the center of separator 30. With such a configuration, it can be said that the degree of curvature of the upper side portion is smaller than the vertical center of the separator 30, which is an outlet for bubbles of gas, and therefore gas is less likely to accumulate in the electrode group 1.

That is, if the degree of curvature of the portion of the outlet, which is the outlet when the gas bubbles are discharged from the electrode group 1 to the outside, is smaller than the upper side portion of the center in the vertical direction of the positive electrode plate 10, the gas is less likely to remain in the electrode group 1 and is easily discharged, and therefore, the increase in the internal resistance of the lead-acid battery can be suppressed. If the flatness of the portion of the positive electrode plate 10 after chemical conversion above the center in the vertical direction is 4.0mm or less, the effect of suppressing the increase in internal resistance of the lead-acid battery is obtained.

In the lead-acid battery according to the first, second, and third embodiments, the small ribs 33 are formed at the ends in the lateral width direction of the separator 30 on the surface of the base 31 facing the positive electrode plate 10, but the small ribs 33 may be formed in a linear shape that continues in the vertical direction of the separator 30 also at the ends in the vertical direction of the separator 30 on the surface of the base 31 facing the positive electrode plate 10. When the positive electrode plate 10 is warped not only in the lateral width direction but also in the vertical direction (that is, when the positive electrode plate 10 is curved in a bowl shape), the small ribs 33 are formed also at the vertical direction end portions of the separator 30 on the surface of the base 31 facing the positive electrode plate 10, and thus the base 31 of the separator 30 can be further prevented from being torn by the positive electrode plate 10 pressing the small ribs 33.

Description of the reference numerals

1: pole plate group

10: positive plate

11: current collecting lug part

12: projection part

20: negative plate

30: partition board

30 a: central part in transverse width direction

30 b: transverse width direction end (lug offset end, current collecting lug offset end)

31: base part

32: main rib part

33: small rib part

Claims

1. A lead-acid battery comprising an electrode group formed by alternately laminating a plurality of positive electrode plates and a plurality of negative electrode plates with separators interposed therebetween,

the lead-acid battery is characterized in that,

a current collecting lug portion protruding upward of the positive electrode plate and a projecting portion protruding upward of the positive electrode plate and having a lower protruding height than the current collecting lug portion are formed at an upper edge portion of the positive electrode plate with a space therebetween along a lateral width direction of the separator,

the separator has: a film-like base; a plurality of main ribs protruding from a surface of the base portion facing the positive electrode plate and contacting the positive electrode plate; and a plurality of small ribs protruding from a surface of the base portion facing the positive electrode plate and having a protruding height lower than that of the main ribs,

the main rib is formed in a linear shape continuous in a vertical direction of the separator, and is formed at a widthwise central portion of the separator on a surface of the base portion facing the positive electrode plate,

the small rib is formed in a linear shape continuous in a vertical direction of the separator, at a lateral width direction end of the separator on a surface of the base portion facing the positive electrode plate, the lateral width direction end at which the small rib is formed being a lateral width direction end having a smaller distance from the protruding portion than a distance from the current collecting ear portion,

the main rib portion disposed on the end portion side closest to the lateral width direction among the main rib portions is located on a portion of the base portion facing the protruding portion.

2. The lead-acid battery according to claim 1,

the protruding tip of the small rib has no corner.

3. The lead-acid battery according to claim 2,

the cross-sectional shape of the protruding tip when the small rib portion is cut along a plane orthogonal to the vertical direction of the separator is a semicircular shape or a semi-elliptical shape.

4. The lead-acid battery according to claim 1,

the protruding height of the protruding portion from the upper edge of the positive electrode plate is 1mm to 3 mm.

5. The lead-acid battery according to claim 1,

the protruding height of the protruding portion from the upper edge of the positive electrode plate is different between the surface side of one of the positive electrode plate and the surface side of the other of the positive electrode plate.

6. The lead-acid battery according to claim 1,

the small rib is formed on both the lateral width direction end portion, which is smaller in distance from the protruding portion than the distance from the current collecting ear portion, and the lateral width direction end portion, which is smaller in distance from the current collecting ear portion than the distance from the protruding portion.

7. The lead-acid battery according to claim 1,

the protruding height of the small rib is 25% to 75% of the protruding height of the main rib.

8. The lead-acid battery according to claim 1,

the main rib has a height of projection such that a central portion of the partition plate in the vertical direction is higher than both end portions of the partition plate in the vertical direction.

9. The lead-acid battery according to claim 1,

the protrusion height of the main rib portion arranged on the center side in the lateral width direction of the separator among the plurality of main rib portions is higher than the protrusion height of the main rib portion arranged on the end side in the lateral width direction of the separator.

10. The lead-acid battery according to claim 1,

in the small rib portions formed at the small rib portions at the widthwise end portions and disposed on the widthwise center side, the small rib portions adjacent to each other are different in the widthwise distance from each other, and the small rib portions on the widthwise outer edge side are smaller in the distance from each other than the small rib portions on the widthwise center side.

11. The lead-acid battery according to claim 1,

the portion of the small rib formed at the corner of the base portion at a position diagonal to the current collecting lug portion intersects with the vertical direction of the separator and is continuous in a direction toward the corner.

12. The lead-acid battery according to claim 11,

the small rib is formed at a corner of the base at a position diagonal to the current collecting lug and has a curved or linear shape.

13. The lead-acid battery according to claim 11,

the small rib portion has a curved portion formed at a corner portion of the base portion at a position diagonal to the current collecting ear portion, and a center of curvature of the small rib portion is located on a straight line connecting the current collecting ear portion and the corner portion of the base portion at a position diagonal to the current collecting ear portion.

14. The lead storage battery according to any one of claims 1 to 13,

the positive electrode plate is curved at four corners thereof toward the separator and is deformed into a bowl shape, and a vertex of a convex surface of the positive electrode plate, which is deformed into the bowl shape, is located below a center of the separator.