JPWO2019097575A1 - Lead-acid battery - Google Patents

Abstract

In one aspect, the present invention includes a battery case having a cell chamber and an open upper surface, an electrode group and an electrolytic solution housed in the cell chamber, and a lid for closing the opening. A lead-acid battery having a plurality of negative electrodes and a plurality of positive electrodes, and the plurality of negative electrodes are connected by a strap formed of an alloy containing Pb and Sn.

Description

The present invention relates to a lead storage battery.

In recent years, various fuel efficiency improvement measures have been studied for automobiles in order to prevent air pollution or global warming. Vehicles with fuel efficiency improvement measures include, for example, micro vehicles such as idling stop system vehicles (hereinafter, also referred to as "ISS vehicles") that reduce the operating time of the engine, and power generation control vehicles that reduce the power generation of the alternator by the power of the engine. Hybrid vehicles are being considered.

In the ISS vehicle and the micro-hybrid vehicle, a large current charge of the lead storage battery is repeated by regenerative charging or the like for a short time. When high-current charging is repeated, electrolysis of water in the electrolytic solution is likely to occur, and oxygen gas and hydrogen gas are generated accordingly, which may increase the pressure in the lead-acid battery. On the other hand, an exhaust plug may be provided on the lid of the lead-acid battery in order to release the pressure. In this case, since the mist of the electrolytic solution is also discharged to the outside of the battery through the exhaust plug, the amount of the electrolytic solution is reduced, and it is necessary to replenish the reduced amount of the electrolytic solution for maintenance. However, since it is desirable that the lead-acid battery is maintenance-free, it is required to suppress the decrease (reduction) of the electrolytic solution.

As a means for suppressing liquid reduction, for example, as disclosed in Patent Document 1, an exhaust chamber is provided inside the lid of the lead storage battery, and the mist of the generated electrolytic solution is retained in the exhaust chamber to be liquefied and liquefied. It is known that the electrolyte is refluxed into the battery.

Japanese Unexamined Patent Publication No. 2005-166318

However, the liquid reduction cannot always be sufficiently suppressed only by the means disclosed in Patent Document 1. Therefore, an object of the present invention is to provide a lead storage battery which is excellent in suppressing liquid reduction.

In one embodiment, the present invention includes a battery case having a cell chamber and an open upper surface, an electrode group and an electrolytic solution housed in the cell chamber, and a lid for closing the opening. A lead-acid battery having a plurality of negative electrodes and a plurality of positive electrodes, and the plurality of negative electrodes are connected by a strap formed of an alloy containing Pb and Sn.

The lid includes a first lid portion, a second lid portion provided on the first lid portion, and an exhaust chamber formed between the first lid portion and the second lid portion. The bottom wall of the first lid portion that separates the exhaust chamber and the cell chamber may be provided with a reflux hole for refluxing the electrolytic solution into the cell chamber.

The negative electrode may contain a resin having a structural unit derived from a phenolic compound. The structural unit may include a structural unit derived from a bisphenol compound. The structural unit may include a structural unit derived from lignin.

The negative electrode may contain a carbon material. The carbon material may contain carbon black.

According to the present invention, it is possible to provide a lead storage battery which is excellent in suppressing liquid reduction.

It is a perspective view which shows the whole structure of the lead storage battery which concerns on one Embodiment. It is a perspective view which shows the electric tank of the lead storage battery shown in FIG. It is a top view of the 1st lid part of the lead storage battery shown in FIG. It is a bottom view of the 2nd lid part of the lead storage battery shown in FIG. It is sectional drawing along the VV line of FIG. It is a perspective view of the electrode plate group of the lead storage battery shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail.

FIG. 1 is a perspective view showing the overall configuration of the lead storage battery of one embodiment. As shown in FIG. 1, in one embodiment, the lead-acid battery 1 is a liquid lead-acid battery including an electric tank 2 having an open upper surface and a lid 3 for closing the opening of the electric tank 2.

FIG. 2 is a perspective view showing the battery case 2 of the lead-acid battery 1 shown in FIG. As shown in FIG. 2, the electric tank 2 has, for example, a hollow rectangular parallelepiped shape. The bottom surface of the electric tank 2 is rectangular, and substantially the entire upper surface of the electric tank 2 is open. The battery case 2 is made of polypropylene, for example. In the present specification, the direction along the long side and the direction along the short side of the bottom surface of the electric tank 2 are the longitudinal direction and the lateral direction of the electric tank 2, respectively.

The inside of the electric tank 2 is divided into 6 sections by, for example, 5 partition walls 21 provided substantially parallel to the lateral side of the electric tank 2. As a result, the first to sixth cell chambers 22a to 22f (hereinafter, collectively referred to as "cell chamber 22") arranged along the longitudinal direction of the electric tank 2 are formed inside the electric tank 2. Has been done. Each of the cell chambers 22 houses an electrode group (electrode plate group, details will be described later).

Each electrode group is also called a cell, and its electromotive force is, for example, 2V. Since a lead-acid battery for an automobile is driven by boosting or stepping down a DC voltage of 12V, for example, six electrode groups housed in each of the six cell chambers 22 are connected in series to form 2V × 6. It has an electromotive force of 12V. The number of cell chambers 22 is not limited to six. It is appropriately selected according to the application of the lead storage battery 1.

As shown in FIG. 2, both side surfaces of the partition wall 21 (planes substantially parallel to the lateral direction of the battery case 2) and the inner surface of the pair of side walls 23 substantially parallel to the partition wall 21 of the battery case 2 are formed on the battery case. A plurality of ribs (rib portions) 24 extending in the height direction (direction perpendicular to the opening surface) of 2 may be provided. That is, both side surfaces of the partition wall 21 and the inner surfaces of the side wall 23 may each have a flat portion 25 and a plurality of ribs 24 protruding from the flat portion 25 and extending in the height direction of the electric tank 2. The rib 24 has a function of appropriately pressurizing (compressing) the electrode group inserted into the cell chamber 22 in the electrode stacking direction.

As shown in FIG. 1, the lid 3 has a double lid structure composed of a first lid portion 4 and a second lid portion 5, and includes the first lid portion 4 and the second lid portion 5. A plurality of exhaust chambers D1 to D6 are formed between them. That is, the lid 3 has a first lid portion 4, a second lid portion 5, and an exhaust chamber formed between the first lid portion 4 and the second lid portion 5. The lid 3 has a substantially rectangular shape in a plan view, and one end and the other end in the longitudinal direction of the lid 3 are attached to one end and the other end in the longitudinal direction of the battery case 2 in each direction along the four sides of the rectangle. The lid 3 is provided on the electric tank 2 in a state in which one end and the other end in the lateral direction of the lid 3 are aligned with each other and the one end and the other end in the lateral direction of the electric tank 2 are aligned with each other. The lid 3 (first lid portion 4 and second lid portion 5) is made of, for example, polypropylene.

The lid 3 is formed with a hollow protruding portion 6 projecting upward from the upper surface of the first lid portion 4 in a region of the upper surface of the first lid portion 4 where the second lid portion 5 is not provided. ing. An indicator mounting hole 7 is formed in a part of the protruding portion 6. The indicator mounting hole 7 is used for mounting an indicator (not shown) that displays the liquid level of the electrolytic solution in the battery case. In the present embodiment, an indicator mounting hole 7 is provided above the cell chamber of one of the cell chambers provided in the battery case 2, and an indicator indicating the liquid level of the electrolytic solution in the cell chamber is provided. It can be mounted in the indicator mounting hole 7. In the present embodiment, the liquid level of the electrolytic solution in another cell chamber is estimated by displaying the liquid level of the electrolytic solution in one cell chamber on the indicator.

The lid 3 is formed with a negative electrode terminal 8 and a positive electrode terminal 9 in a region of the upper surface of the first lid portion 4 where the second lid portion 5 is not provided. The negative electrode terminal 8 and the positive electrode terminal 9 are connected to a group of electrode plates housed in the battery case 2 via a negative electrode column and a positive electrode column.

Hereinafter, the details of the lid 3 will be described with reference to FIGS. 3 to 5. FIG. 3 is a plan view of the first lid portion, and FIG. 4 is a bottom view of the second lid portion. FIG. 5 is a cross-sectional view taken along the line VV of FIG. 3, and is a cross-sectional view of the lid 3 in a state where the first lid portion 4 and the second lid portion 5 are welded together.

As shown in FIG. 3, the first lid portion 4 has a substantially rectangular shape in a plan view, and a second lid portion 5 is arranged on a part of the first lid portion 4. The exhaust chamber component 400 is formed. The exhaust chamber component 400 has one end 400a and the other end 400b in the longitudinal direction positioned closer to one end 4a and the other end 4b in the longitudinal direction of the first lid 4, respectively, and one end 400c in the lateral direction is the first. The lid 4 is located near the center of the lid 4 in the lateral direction, and the other end 400d in the lateral direction is located near the other end 4d of the first lid 4 in the lateral direction (the lateral direction of the battery case). It is formed in a state of being. A peripheral wall portion 40 extending along the outer peripheral edge thereof is formed on the upper surface of the exhaust chamber constituent portion 400, and a first lid side recess is formed inside the peripheral wall portion 40. In the example shown in FIG. 3, in order to increase the width dimension (length in the lateral direction) of the portion closer to one end 4a and the other end 4b in the longitudinal direction of the exhaust chamber component 400, the exhaust chamber component 400 Projecting portions 401 and 402 are formed so as to project to one end side in the lateral direction from the portion closer to the center in the longitudinal direction of the above.

As shown in FIG. 4, the second lid portion 5 has the same contour shape as the exhaust chamber constituent portion 400, and the exhaust chamber configuration is formed on one end 5a side and the other end 5b side in the longitudinal direction, respectively. Similar to the protrusions 401 and 402 at both ends of the portion 400, the protrusions 501 and 502 protruding in the lateral direction are formed. Further, as shown in FIG. 4, a peripheral wall portion 50 extending along the outer peripheral edge thereof is also formed on the lower surface of the second lid portion 5, and a second lid side concave portion is formed inside the peripheral wall portion 50. ing. In the example shown in FIG. 4, an outer wall portion 51 that surrounds the outside of the peripheral wall portion 50 is formed on the lower surface of the second lid portion 5.

The second lid portion 5 is provided on the exhaust chamber constituent portion 400, and the first lid portion 4 and the second lid portion 5 are joined by heat welding. Specifically, in the second lid portion 5, one end 5a and the other end 5b in the longitudinal direction of the second lid portion 5 are made to coincide with the one end 4a and the other end 4b in the longitudinal direction of the first lid portion 4, respectively. , One end 5c and the other end 5d in the lateral direction of the second lid portion 5 are aligned with the lateral end 400c and the other end 400d of the exhaust chamber constituent portion of the first lid portion 4, respectively. It is arranged on the component 400. Further, the exhaust chamber constituent portion 400 and the second lid portion 5 are joined in a state where the peripheral wall portion 40 and the peripheral wall portion 50 are combined, and the first lid portion side recess and the second lid portion side are joined. A space for forming an exhaust chamber is formed between the exhaust chamber constituent portion 400 of the first lid portion 4 and the second lid portion 5 by the recess.

In the space between the exhaust chamber constituent portion 400 of the first lid portion 4 and the second lid portion 5, the first to sixth cell chambers 22a to 22f are located on the first to sixth cell chambers 22a to 22f, respectively. Exhaust chambers D1 to D6 of No. 6 are formed (see FIGS. 3 and 4). These exhaust chambers have a predetermined pattern of first partition wall portions formed inside the exhaust chamber constituent portion 400 of the first lid portion 4 and the peripheral wall portion 50 of the second lid portion 5 with a predetermined plate thickness. It is formed by joining 42 and 52 to each other. The exhaust chambers D1 to D6 have a function of retaining the mist of the electrolytic solution generated from each cell chamber 22 in the electric tank 2 inside and refluxing the electrolytic solution liquefied in the exhaust chamber into each cell chamber 22. ..

In the present embodiment, a part of the first exhaust chamber D1 and the sixth exhaust chamber D6 arranged at both ends is provided with a first partition portion provided in the first lid portion 4 and the second lid portion 5. By partitioning by the second partition walls 42a and 52a formed in a part of 42 and 52, one end 400a side and the other end 400b side of the exhaust chamber component 400 of the first lid 4 in the longitudinal direction, and the other end 400b side, and Centralized exhaust chambers E1 and E2 are formed on one end 5a side and the other end 5b side of the second lid portion 5 in the longitudinal direction, respectively.

Each exhaust chamber is a pair of inner side surfaces Sa and Sb in the longitudinal direction facing each other in a state facing the longitudinal direction of the first lid portion 4, and a pair facing each other in a state facing the lateral side of the first lid portion 4. It has inner side surfaces Sc and Sd in the lateral direction, and four corner portions C1 to C4 are formed in each exhaust chamber. In the present specification, for convenience of explanation, among the four inner side surfaces Sa to Sd of each exhaust chamber, the inner side surfaces Sa and Sb facing the longitudinal direction of the first lid portion 4 are referred to as longitudinal inner surfaces, and the first The inner side surfaces Sc and Sd of the lid portion 4 of 1 facing the lateral side are referred to as the lateral side surfaces in the lateral direction.

In the three exhaust chambers D1 to D3 arranged closer to one end 4a in the longitudinal direction of the first lid portion 4, the first lid portion 4 of the pair of inner side surfaces in the longitudinal direction of the first lid portion 4 The longitudinal inner surface located on one end 4a side in the longitudinal direction is one longitudinal inner surface Sa, and the longitudinal inner surface located on the other end 4b side of the first lid 4 in the longitudinal direction is the other longitudinal direction. The inner surface is Sb. Further, in the other three exhaust chambers D4 to D6 arranged near the other end 4b in the longitudinal direction of the first lid portion 4, among the pair of inner surfaces in the longitudinal direction, the longitudinal length of the first lid portion 4 The longitudinal inner surface located on the other end 4b side of the direction is defined as one longitudinal inner surface Sa, and the longitudinal inner surface located on the longitudinal end 4a side of the first lid 4 is the other longitudinal inner surface. It is Sb.

The exhaust chambers D1 to D6 are formed in a substantially square shape in a plan view, but the first exhaust chambers D1 and the sixth exhaust chambers D6 arranged at both ends in the longitudinal direction of the first lid portion 4 are respectively. Since the centralized exhaust chambers E1 and E2 are formed in a part of the above, one of the inner side surfaces Sa in the longitudinal direction has a deformed shape.

As described above, the exhaust chambers D1 to D6 and the centralized exhaust chambers E1 and E2 are formed between the exhaust chamber constituent portion 400 of the first lid portion 4 and the second lid portion 5, and further. As will be described later, various fluid passages for connecting the exhaust chambers D1 to D6 to the centralized exhaust chambers E1 and E2 are formed. These fluid passages are composed of first partition wall portions 42, 52 provided on the first lid portion 4 and the second lid portion 5, respectively, and joined to each other. In the following description, the first is mainly the first. The configuration of the fluid passage provided between the first lid portion 4 and the second lid portion 5 will be described with reference to FIG. 3 showing the lid portion 4. The patterns of the wall portions provided on the first lid portion and the second lid portion to form the exhaust chamber, the fluid passage, and the like are in a mirror image relationship with each other.

As shown in FIG. 3, a first longitudinal fluid passage L1 and a second longitudinal fluid passage L2 are connected between the exhaust chamber component 400 of the first lid 4 and the second lid 5. And the first short-direction fluid passage W1a and the second short-direction fluid passage W1b are formed.

The first longitudinal fluid passage L1 is on the other end 400d side of the exhaust chamber component 400 in the lateral direction, and the outside of the exhaust chambers D1 to D6 (between the exhaust chambers D1 to D6 and the peripheral wall portion 40) is the exhaust chamber. It is provided so as to extend linearly along the longitudinal direction of the component 400. On one end side and the other end side in the longitudinal direction of the first longitudinal fluid passage L1, width dimensions (length in the lateral direction) are provided at positions corresponding to the protrusions 401 and 402 of the exhaust chamber component 400, respectively. The enlarged enlarged portions L11 and L12 are formed. The end portions of the enlarged portions L11 and L12 of the first longitudinal fluid passage L1 are formed between the first exhaust chamber D1 and the sixth exhaust chamber D6 and the peripheral wall portion 40, respectively. Through 44, it is connected to the centralized exhaust chambers E1 and E2.

The second longitudinal fluid passage L2 is linear at one end 400c side of the exhaust chamber component 400 in the lateral direction and outside the exhaust chambers D1 to D6 (between the exhaust chambers D1 to D6 and the peripheral wall portion 40). It is provided so as to extend. The first lateral fluid passage W1a and the second lateral fluid passage W1b are adjacent to each other between the second and third exhaust chambers D2 and D3 and the fourth and fifth exhaust chambers D4 and D5, respectively. The space is provided so as to extend in the lateral direction of the exhaust chamber component 400, and connects between the first longitudinal fluid passage L1 and the second longitudinal fluid passage L2.

The second longitudinal fluid passage L2 is divided into a first portion L2a and a second portion L2b by a partition wall portion 45 provided at the central portion in the longitudinal direction of the exhaust chamber constituent portion 400. The first longitudinal fluid passage L1 passes through the first lateral fluid passage W1a and the second lateral fluid passage W1b, and the first portion L2a and the second portion of the second longitudinal fluid passage L2. They are connected to L2b respectively.

As shown in FIG. 3, the exhaust chambers D1 to D6 are injected with an electrolytic solution that penetrates the bottom wall of each exhaust chamber that partitions between each exhaust chamber and the corresponding cell chambers 22a to 22f. A reflux hole h having a size that also serves as a hole is provided. The return hole h is formed between one longitudinal inner surface Sa of each exhaust chamber and one lateral inner surface Sc of each exhaust chamber located on the second longitudinal fluid passage L2 side. It is located near the corner portion C1 of No. 1, and only one is provided in each exhaust chamber. The exhaust chambers D1 to D6 are connected to the first to sixth cell chambers 22a to 22f through the reflux holes h provided in the respective bottom wall portions.

In each of the exhaust chambers of the first lid portion 4 and the second lid portion 5, fluid passage forming wall portions 46 and 56 extending along the other longitudinal inner surface Sb of each exhaust chamber are provided. A third lateral fluid passage W2 extending in the lateral direction of the exhaust chamber constituent portion 400 is formed between the fluid passage forming wall portions 46 and 56 and the longitudinal inner side surface Sb. One end of the third lateral fluid passage W2 opens into the fourth corner portion C4 at a diagonal position of the first corner portion C1, and the other end opens into the second longitudinal fluid passage L2. doing.

In each of the exhaust chambers of the first lid portion 4 and the second lid portion 5, a fluid passage forming wall is provided near the opening at one end of the third lateral fluid passage W2 (near the fourth corner portion C4). The first barrier portions 47 and 57 integrated with the portions 46 and 56 are provided. The first barrier portions 47, 57 project from the fluid passage forming wall portions 46, 56 toward one longitudinal inner surface Sa side of each exhaust chamber, and terminate at a position in front of the one longitudinal inner surface Sa. doing. The first barrier portions 47 and 57 are provided in a state of being integrated with the first lid portion 4 and the second lid portion 5. An electrolytic solution accommodating space A is formed between the first barrier portions 47 and 57 and one of the inner side surfaces Sc in the lateral direction. The terminal positions of the tips of the first barrier portions 47 and 57 are set so that at least a part of the reflux holes h is located in the electrolytic solution accommodating space A.

In each of the exhaust chambers of the first lid portion 4 and the second lid portion 5, one of the longitudinal facing surfaces Sc of each exhaust chamber is located closer to the first barrier portions 47 and 57 than the return hole h. Second barrier portions 48, 58 are provided so as to project from the side and extend toward the fluid passage forming wall portions 46, 56 in the electrolytic solution accommodating space A. The barrier portions 48 and 58 are integrally provided with the first lid portion 4 and the second lid portion 5. The second barrier portions 48 and 58 are inclined toward the second corner portion C2 formed between the other longitudinal inner surface Sb and the one lateral inner surface Sc of each exhaust chamber. It is provided. The tips of the second barrier portions 48 and 58 are terminated at a position in front of the fluid passage forming wall portions 46 and 56.

In each of the exhaust chambers of the first lid portion 4 and the second lid portion 5, a second barrier portion 48 is provided from a position in front of the tips of the first barrier portions 47 and 57 along the lateral direction of the exhaust chamber. A first protruding wall portion 47a, 57a projecting toward the 58th side and terminating at a position in front of the second barrier portions 48, 58 is further provided. In each exhaust chamber, a position protruding from the position in front of the tips of the second barrier portions 48 and 58 toward the inner side surface Sc side in the lateral direction of each exhaust chamber and in front of the inner side surface Sc in the lateral direction. Second protruding wall portions 48a and 58a terminated by are further provided. The first protruding wall portions 47a, 57a and the second protruding wall portions 48a, 58a are integrally provided with the first lid portion 4 and the second lid portion 5.

In the first lid portion 4, the upper surface of the bottom wall portion of each exhaust chamber is gradually lowered from the vicinity of the opening at one end of the third lateral fluid passage W2 toward the reflux hole h. Is sloped. The bottom surface of the first longitudinal fluid passage L1 gradually becomes lower toward the portion where the first and second lateral fluid passages W1a and W1b and the first longitudinal fluid passage L1 meet. It is sloped to go. The bottom surfaces of the first and second lateral fluid passages W1a and W1b are inclined so as to gradually decrease from the first longitudinal fluid passage L1 side toward the second longitudinal fluid passage L2 side. It is attached. The bottom surface of the second longitudinal fluid passage L2 is inclined so as to gradually decrease toward the opening at the other end of the third lateral fluid passage W2 provided in each exhaust chamber. There is. In FIG. 3, the inclination of each of the above parts is indicated by an arrow. Each arrow indicates that the front end side is lower than the rear end side. With such a configuration, the mist of the electrolytic solution discharged from the reflux holes h in each exhaust chamber into each exhaust chamber is collected by the first barrier portions 47, 57, the second barrier portions 48, 58, and the first protruding wall. After touching and liquefying 47a, 57a and the second protruding walls 48a, 58a, it is possible to return to the return hole h of each exhaust chamber along the bottom surface of each exhaust chamber.

As shown in FIG. 4, exhaust ports 65 for opening the centralized exhaust chambers E1 and E2 to the outside are formed at one end and the other end of the second lid portion 5 in the longitudinal direction. Explosion-proof filters 66 are housed in the centralized exhaust chambers E1 and E2. The exhaust gas that has flowed into each centralized exhaust chamber through the first longitudinal fluid passage L1 is discharged to the outside through the explosion-proof filter 66 and the exhaust port 65.

A liquid injection port 60 is formed in the second lid portion 5. The liquid injection port 60 is provided at a position consistent with the return hole h in each exhaust chamber. A screw for attaching a stopper is formed on the inner circumference of the liquid injection port 60.

As shown in FIG. 5, the lid 3 is provided with a welded portion 405 and a positioning rib 406. When the lid 3 is attached to the electric tank 2, the welded portion 405 is welded to the upper end of the partition wall that divides the cell chambers in the electric tank, and forms a wall portion that separates the cell chambers together with the partition wall on the electric tank side. To do. Further, the positioning rib 406 engages with the side surface of the upper end of the partition wall between the cell chambers on the battery case side when the welding portion 405 is welded to the upper end of the partition wall between the cell chambers of the battery chamber 2, and the welding portion A positioning rib for positioning the 405 with respect to the partition wall on the battery case side.

In the above embodiment, the second lid portion 5 is provided with a liquid injection hole, but the second lid portion 5 is not provided with a liquid injection hole, and after the electrolytic solution is injected, the first lid portion 4 is provided. And the second lid portion 5 may be welded together.

In the above embodiment, of the pair of inner side surfaces Sc and Sd in the lateral direction of each exhaust chamber, Sc is defined as the inner surface in one lateral direction and Sd is defined as the inner surface in the other lateral direction, but Sd and Sc. May be one side in the short direction and the other side in the short direction. Similarly, Sb may be one longitudinal inner surface and Sa may be the other longitudinal inner surface.

In the above embodiment, the return hole h is composed of an aggregate of a plurality of holes, but the return hole h may be composed of a single hole. The return hole h may also have a function as a ventilation hole by making the return hole h larger or increasing the number of holes forming the return hole h.

In the above embodiment, the first protruding wall portions 47a, 57a and the second protruding wall portions 48a, 58a are provided, but the first protruding wall portions 47a, 57a and the second protruding wall portions 47a, 57a. It is not necessary to provide the wall portions 48a and 58a.

Subsequently, a group of electrodes housed in each of the cell chambers 22 will be described. FIG. 6 is a perspective view showing the electrode group. As shown in FIG. 6, the electrode group 10 includes a plate-shaped negative electrode (negative electrode plate) 11, a plate-shaped positive electrode (positive electrode plate) 12, and a separator 13 arranged between the negative electrode 11 and the positive electrode 12. It has. The negative electrode 11 includes a negative electrode current collector (negative electrode lattice body) 14 and a negative electrode active material 15 held by the negative electrode current collector 14. The positive electrode 12 includes a positive electrode current collector (positive electrode lattice body) 16 and a positive electrode active material 17 held by the positive electrode current collector 16. In this specification, the negative electrode after chemical conversion excluding the negative electrode current collector is defined as "negative electrode active material", and the positive electrode after chemical conversion excluding the positive electrode current collector is defined as "positive electrode active material". ..

The electrode group 10 has a structure in which a plurality of negative electrodes 11 and 12 are alternately laminated in a direction substantially parallel to the opening surface of the battery case 2 via a separator 13. That is, the electrode group 10 is housed in each of the cell chambers 22 so that the main surfaces of the negative electrode 11 and the positive electrode 12 extend in the direction perpendicular to the opening surface of the battery case 2.

In the electrode group 10, the ears 11a of each negative electrode current collector 14 in the plurality of negative electrodes 11 are connected (for example, collective welding) by a strap (negative electrode side strap) 18. Similarly, the ears 12a of each of the positive electrode current collectors 16 in the plurality of positive electrodes 12 are connected (for example, collective welding) by a strap (positive electrode side strap) 19. The negative electrode side strap 18 and the positive electrode side strap 19 are connected to the negative electrode terminal 8 and the positive electrode terminal 9 via the negative electrode column and the positive electrode column, respectively.

The separator 13 is formed in a bag shape, for example, and houses the negative electrode 11. The separator 13 is made of, for example, polyethylene (PE), polypropylene (PP), or the like. The separator 13 may have inorganic particles such as SiO ₂ and Al ₂ O ₃ adhered to a woven fabric, a non-woven fabric, a porous film, or the like formed of these materials.

The negative electrode current collector 14 and the positive electrode current collector 16 are each made of a lead alloy. The lead alloy may be an alloy containing Sn, Ca, Sb, Se, Ag, Bi and the like in addition to Pb, and specifically, for example, an alloy containing Pb, Sn and Ca (Pb-Sn). -Ca-based alloy) may be used.

The negative electrode active material 15 contains at least Pb (elemental substance) as a Pb component, and may further contain a Pb component (for example, PbSO ₄ ) other than Pb and an additive, if necessary. The negative electrode active material 15 preferably contains porous spongy lead (Spongy Lead) as a Pb component.

The content of the Pb component may be 90% by mass or more or 95% by mass or more, and may be 99% by mass or less or 98% by mass or less, based on the total mass of the negative electrode active material.

From the viewpoint of further suppressing liquid reduction, the negative electrode active material 15 preferably further contains a resin having a structural unit derived from a phenolic compound (hereinafter, also referred to as “phenolic resin”) as an additive. That is, the negative electrode 11 preferably further contains a resin having a structural unit derived from a phenolic compound in the negative electrode active material 15. The phenolic resin preferably further has a sulfonic acid group (sulfo group) or a sulfonic acid base. In this case, the sulfonic acid group or the sulfonic acid base may be contained in the structural unit derived from the phenolic compound, or may be contained in the structural unit different from the structural unit derived from the phenolic compound. Good.

The content of the phenolic resin may be 0.01% by mass or more, 0.05% by mass or more or 0.1% by mass or more, based on the total mass of the negative electrode active material, and is 2% by mass or less and 1% by mass. It may be% or less or 0.5% by mass or less.

The structural unit derived from the phenolic compound preferably contains the structural unit derived from the bisphenol compound from the viewpoint of particularly suppressing the liquid reduction, and from the viewpoint of achieving both the suppression of the liquid reduction and the excellent DCA performance. It preferably comprises a structural unit derived from lignin. That is, the phenol-based resin is a bisphenol-based resin containing a sulfonic acid group or a sulfonic acid base (hereinafter, also referred to as "bisphenol-based resin") from the viewpoint of particularly suppressing liquid reduction, and is excellent in suppressing liquid reduction and DCA. From the viewpoint of achieving both performance, lignin sulfonic acid or a salt thereof (hereinafter, also referred to as "lignin sulfonic acid (salt)") is preferable.

The bisphenol resin has a structural unit derived from the bisphenol compound as a structural unit derived from the phenol compound. The bisphenol resin is, for example, (a) a bisphenol compound (hereinafter, also referred to as “(a) component”) and (b) a compound having a sulfonic acid group (sulfo group) (hereinafter, also referred to as “(b) component”). In the reaction of and, it can be obtained by substituting the hydrogen atom of the sulfonic acid group with, for example, a metal atom, if necessary. In the reaction of the component (a) and the component (b), at least one selected from the group consisting of (c) formaldehyde and a formaldehyde derivative (hereinafter, also referred to as “component (c)”) may be further reacted.

Examples of the component (a) include 2,2-bis (4-hydroxyphenyl) propane (hereinafter, also referred to as “bisphenol A”), bis (4-hydroxyphenyl) methane, and 1,1-bis (4-hydroxyphenyl). ) Etan, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) butane, bis ( 4-Hydroxyphenyl) diphenylmethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, and bis (4-hydroxyphenyl) Examples include sulfone (hereinafter, also referred to as "bisphenol S"). As the component (a), one type can be used alone or two or more types can be used in combination. The component (a) is preferably bisphenol A from the viewpoint of further excellent charge acceptability, and preferably bisphenol S from the viewpoint of further excellent discharge characteristics.

As the component (a), it is preferable to use bisphenol A and bisphenol S in combination from the viewpoint of improving charge acceptability, discharge characteristics and cycle characteristics in a well-balanced manner. In this case, the content of bisphenol A in the reaction for obtaining the bisphenol resin is preferably based on the total amount of bisphenol A and bisphenol S from the viewpoint of improving charge acceptability, discharge characteristics and cycle characteristics in a well-balanced manner. It is 70 mol% or more, more preferably 75 mol% or more, still more preferably 80 mol% or more. The content of bisphenol A is preferably 99 mol% or less, more preferably 98 mol% or less, based on the total amount of bisphenol A and bisphenol S, from the viewpoint of improving charge acceptability, discharge characteristics and cycle characteristics in a well-balanced manner. , More preferably 97 mol% or less.

The component (b) may be a compound having an amino group and a sulfonic acid group. Examples of the compound having an amino group and a sulfonic acid group include 4-aminobenzenesulfonic acid (also known as sulfanilic acid), aminoethylsulfonic acid (also known as taurine), and 5-amino-1-naphthalenesulfonic acid (also known as laurentic acid). ).

As the component (b), one type can be used alone or two or more types can be used in combination. The component (b) is preferably 4-aminobenzenesulfonic acid from the viewpoint of further improving charge acceptability.

The content of the component (b) in the reaction for obtaining the bisphenol resin is preferably 0.5 mol or more, more preferably 0. Mol, with respect to 1 mol of the component (a) from the viewpoint of further improving the discharge characteristics. It is 6 mol or more, more preferably 0.7 mol or more, and particularly preferably 0.8 mol or more. The content of the component (b) is preferably 2.0 mol or less, more preferably 1.5 mol or less, and further, with respect to 1 mol of the component (a), from the viewpoint of further improving the discharge characteristics and cycle characteristics. It is preferably 1.3 mol or less, particularly preferably 1.0 mol or less.

As the formaldehyde as the component (c), formaldehyde in formalin (for example, an aqueous solution of 37% by mass of formaldehyde) may be used. Examples of formaldehyde derivatives include paraformaldehyde, hexamethylenetetramine and trioxane. As the component (c), one type can be used alone or two or more types can be used in combination. Formaldehyde and formaldehyde derivative may be used in combination as the component (c).

The component (c) is preferably a formaldehyde derivative, more preferably paraformaldehyde, from the viewpoint that excellent cycle characteristics can be easily obtained. Paraformaldehyde has, for example, a structure represented by the following formula (1).
HO (CH ₂ O) _n1 H ... (1)
In the formula (1), n1 represents an integer of 2 to 100.

The formaldehyde-equivalent amount of the component (c) in the reaction for obtaining the bisphenol resin is preferably 2 mol or more with respect to 1 mol of the component (a) from the viewpoint of improving the reactivity of the component (b). It is more preferably 2.2 mol or more, still more preferably 2.4 mol or more. The formaldehyde-equivalent amount of the component (c) is obtained by the reaction of the components (a), (b) and (c), and the structural unit having a benzoxazine ring can be easily reduced. With respect to 1 mol, it is preferably 3.5 mol or less, more preferably 3.2 mol or less, still more preferably 3 mol or less, particularly preferably less than 2.8 mol, and extremely preferably 2.5 mol or less.

The bisphenol resin preferably has at least one of a structural unit represented by the following formula (I) and a structural unit represented by the following formula (II).

In formula (I), X ¹ represents a divalent group, Y ¹ represents a divalent aromatic hydrocarbon group, an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and R ¹¹ , R ¹² and R ¹³ independently represents a metal atom or a hydrogen atom, n11 represents an integer of 1 to 300, and n12 represents an integer of 1 to 3. The hydrogen atom directly bonded to the carbon atom constituting the benzene ring may be substituted with an alkyl group having 1 to 5 carbon atoms.

In formula (II), X ² represents a divalent group, Y ² represents a divalent aromatic hydrocarbon group, an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, and R ²¹ , R ²² and R ²³ independently represents a metal atom or a hydrogen atom, n21 represents an integer of 1 to 300, and n 22 represents an integer of 1 to 3. The hydrogen atom directly bonded to the carbon atom constituting the benzene ring may be substituted with an alkyl group having 1 to 5 carbon atoms.

The ratio of the structural unit represented by the formula (I) and the structural unit represented by the formula (II) is not particularly limited and may change depending on the synthesis conditions and the like. As the bisphenol resin, a resin having only one of the structural unit represented by the formula (I) and the structural unit represented by the formula (II) may be used.

Examples of X ¹ and X ² include an alkylidene group (for example, a methylidene group, an ethylidene group, an isopropylidene group and a sec-butylidene group), a cycloalkylidene group (for example, a cyclohexylidene group), and a phenylalkylidene group (for example, a diphenylmethylidene group and a phenyl group). Organic groups such as ethylidene group; sulfonyl group and the like can be mentioned. The X ¹ and ^{X 2,} isopropylidene group _{(-C (CH 3) 2 -} ) from the viewpoint of further excellent charge acceptability are preferred, from further excellent in view discharge characteristics sulfonyl group (-SO ₂ -) preferable. X ¹ and X ² may be substituted with a halogen atom such as a fluorine atom. When X ¹ or X ² is a cycloalkylidene group, the hydrocarbon ring may be substituted with an alkyl group or the like.

The divalent aromatic hydrocarbon group represented by Y ¹ or Y ² includes, for example, a phenylene group and a naphthylene group, and the divalent aliphatic hydrocarbon group includes, for example, an ethylene group and a trimethylene group, and a divalent alicyclic group. Examples of the type hydrocarbon group include a cyclohexylidene group. Y ¹ and Y ² are preferably a phenylene group or a naphthylene group from the viewpoint of further excellent charge acceptability. The divalent aromatic hydrocarbon group, aliphatic hydrocarbon group or alicyclic hydrocarbon group represented by Y ¹ and Y ² may be substituted with halogen atoms such as fluorine atoms, respectively.

The metal atom represented by R ¹¹ , R ¹² , R ¹³ , R ²¹ , R ²² or R ²³ is, for example, a sodium atom, a potassium atom, a magnesium atom or a calcium atom.

The bisphenol resin may have, for example, structural units represented by the following formulas (III) to (VI). It is presumed that the reason why the structural units represented by the formulas (III) to (VI) are generated is that the formaldehyde component undergoes an addition reaction to the benzene ring of the component (a).

X ³ , X ⁴ , X ⁵ and X ⁶ are synonymous with X ¹ and X ² , respectively, and R ³¹ , R ³² , R ³³ , R ⁴¹ , R ⁴² , R ⁴³ , R ⁵¹ , R ⁵² , R ^{61, respectively.} And R ⁶² are independently synonymous with R ²¹ , R ²² and R ²³ , respectively, n31, n41, n51 and n61 are independently synonymous with n11 and n21, respectively, and n32 and n42 are independently synonymous with n12, respectively. And n22 are synonymous with. The hydrogen atom directly bonded to the carbon atom constituting the benzene ring may be substituted with an alkyl group having 1 to 5 carbon atoms.

The weight average molecular weight of the bisphenol resin is preferably 20,000 or more, more preferably 30,000 or more, still more preferably 40,000 or more, and particularly preferably 50,000 or more, from the viewpoint of further improving the cycle characteristics. The weight average molecular weight of the bisphenol resin is preferably 80,000 or less, more preferably 70,000 or less, still more preferably 60,000 or less, from the viewpoint of further improving the cycle characteristics. From these viewpoints, the weight average molecular weight of the bisphenol resin is preferably 20000 to 80,000, more preferably 30,000 to 70,000, still more preferably 40,000 to 60,000, and particularly preferably 50,000 to 60,000.

The weight average molecular weight of the bisphenol resin can be measured, for example, by gel permeation chromatography (hereinafter referred to as "GPC") under the following conditions.
(GPC condition)
Equipment: High Performance Liquid Chromatograph LC-2200 Plus (manufactured by JASCO Corporation)
Pump: PU-2080
Differential refractometer: RI-2031
Detector: Ultraviolet-visible absorptiometer UV-2075 (λ: 254 nm)
Column oven: CO-2065
Columns: TSKgel SuperAW (4000), TSKgel SuperAW (3000), TSKgel SuperAW (2500) (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Eluent: Methanol solution containing LiBr (10 mM) and triethylamine (200 mM) Flow velocity: 0.6 mL / min Molecular weight Standard sample: Polyethylene glycol (Molecular weight: 1.10 x 10 ⁶ , 5.80 x 10 ⁵ , 2.55 × 10 ⁵ , 1.46 × 10 ⁵ , 1.01 × 10 ⁵ , 4.49 × 10 ⁴ , 2.70 × 10 ⁴ , 2.10 × 10 ⁴ ; manufactured by Toso Co., Ltd., diethylene glycol (molecular weight: 1) .06 × 10 ² ; manufactured by Kishida Chemical Co., Ltd.), dibutyl hydroxytoluene (molecular weight: 2.20 × 10 ² ; manufactured by Kishida Chemical Co., Ltd.)

The method for producing a bisphenol-based resin includes, for example, a resin manufacturing process for obtaining a bisphenol-based resin by reacting the component (a), the component (b), and the component (c). The bisphenol resin can be obtained, for example, by reacting the component (a), the component (b) and the component (c) in a reaction solvent. The reaction solvent is preferably water (for example, ion-exchanged water). In this step, an organic solvent, a catalyst, an additive, or the like may be used to accelerate the reaction.

In the resin manufacturing process, from the viewpoint of further improving the cycle characteristics, the blending amount of the component (b) is 0.5 to 2.0 mol with respect to 1 mol of the component (a), and the blending of the component (c) It is preferable that the amount is 2 to 3.5 mol in terms of formaldehyde with respect to 1 mol of the component (a), and the blending amount of the component (b) is 0.5 to 2.0 per mol of the component (a). It is more preferable that the amount of the component (c) is 2 to 2.5 mol in terms of formaldehyde with respect to 1 mol of the component (a). The preferable blending amount of the component (b) and the component (c) is in the above-mentioned range for each of the blending amounts of the component (b) and the component (c).

The bisphenol resin is preferably obtained by reacting the component (a), the component (b) and the component (c) under basic conditions (alkaline conditions) from the viewpoint that a sufficient amount of the bisphenol resin can be easily obtained. .. In order to adjust to the basic condition, a basic compound may be used. Examples of the basic compound include potassium hydroxide and potassium carbonate. As the basic compound, one type can be used alone or two or more types can be used in combination. The basic compound is preferably potassium hydroxide from the viewpoint of excellent reactivity.

When the reaction solution at the time of reaction is neutral (pH = 7), the reaction for producing a bisphenol resin may be difficult to proceed, and when the reaction solution is acidic (pH <7), a side reaction (for example, benzo) A reaction to form a structural unit having an oxazine ring) may proceed. Therefore, the pH of the reaction solution at the time of the reaction is preferably alkaline (more than 7), more preferably 7. from the viewpoint of easily suppressing the progress of the side reaction while proceeding with the formation reaction of the bisphenol resin. It is 1 or more, more preferably 7.2 or more. The pH of the reaction solution is preferably 12 or less, more preferably 10 or less, still more preferably 9 or less, from the viewpoint of suppressing the progress of hydrolysis of the group derived from the component (b) in the bisphenol resin. The pH of the reaction solution can be measured, for example, with a twin pH meter AS-212 manufactured by HORIBA, Ltd. pH is defined as pH at 25 ° C.

Since it is easy to adjust the pH as described above, the blending amount of the strong basic compound is preferably 1.01 mol or more, more preferably 1.02 mol or more, still more preferably 1.02 mol or more, based on 1 mol of the component (b). Is 1.03 mol or more. From the same viewpoint, the blending amount of the strong basic compound is preferably 1.1 mol or less, more preferably 1.08 mol or less, still more preferably 1.07 mol or less, based on 1 mol of the component (b). is there. Examples of the strong basic compound include potassium hydroxide and potassium carbonate.

In the synthesis reaction of the bisphenol resin, it is sufficient that the component (a), the component (b) and the component (c) react to obtain the bisphenol resin. For example, the component (a), the component (b) and the component (c) The components may be reacted at the same time, or the remaining one component may be reacted after reacting two components of the component (a), the component (b) and the component (c).

The synthetic reaction of the bisphenol resin is preferably carried out in two steps as follows. In the first-stage reaction, for example, the component (b), the solvent (water, etc.) and the basic compound are charged and then stirred, and the hydrogen atom of the sulfo group in the component (b) is replaced with a metal atom such as a potassium atom. (B) Obtain a metal salt such as the potassium salt of the component. This makes it easy to suppress side reactions in the condensation reaction described later. The temperature of the reaction system is preferably 0 ° C. or higher, more preferably 25 ° C. or higher, from the viewpoint of excellent solubility of the component (b) in a solvent (water or the like). The temperature of the reaction system is preferably 80 ° C. or lower, more preferably 70 ° C. or lower, still more preferably 65 ° C. or lower, from the viewpoint of easily suppressing side reactions. The reaction time is, for example, 30 minutes.

In the reaction of the second step, for example, a bisphenol resin is obtained by adding the component (a) and the component (c) to the reaction product obtained in the first step and causing a condensation reaction. The temperature of the reaction system is preferably 75 ° C. or higher, more preferably 85, from the viewpoint of excellent reactivity of the components (a), (b) and (c), and reduction of side reaction products. ° C. or higher, more preferably 92 ° C. or higher. The temperature of the reaction system is preferably 100 ° C. or lower, more preferably 98 ° C. or lower, still more preferably 96 ° C. or lower, from the viewpoint of easily suppressing side reactions. The reaction time is, for example, 5 to 20 hours.

The content of the bisphenol resin may be 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more based on the total mass of the negative electrode active material, and may be 2% by mass or less and 1% by mass. It may be% or less or 0.5% by mass or less.

The lignin sulfonic acid (salt) is lignin sulfonic acid or a salt thereof in which a part of the lignin decomposition product is sulfonated. The lignin sulfonic acid (salt) has a structural unit derived from lignin as a structural unit derived from a phenolic compound, and also has a sulfonic acid group or a sulfonic acid base. The lignin sulfonic acid (salt) has, for example, a structure in which a sulfonic acid group or a sulfonic acid base is bonded to a carbon atom at the α-position adjacent to a phenylene group. The salt of lignin sulfonic acid may be, for example, a sodium salt, a potassium salt, a magnesium salt or a calcium salt.

Ligno sulfonic acid (salt) can be obtained, for example, by neutralizing the black liquor remaining after cooking wood chips to remove cellulose with sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, or the like. Can be done.

The weight average molecular weight of the lignin sulfonic acid (salt) is preferably 3000 or more from the viewpoint of suppressing elution of the lignin sulfonic acid (salt) from the electrode into the electrolytic solution in the lead storage battery and obtaining more excellent cycle characteristics. It is more preferably 7,000 or more, still more preferably 8,000 or more. The weight average molecular weight of lignin sulfonic acid (salt) is preferably 70,000 or less, more preferably 50,000 or less, still more preferably 40,000 or less, particularly preferably 30,000 or less, and extremely preferably 20,000, from the viewpoint of excellent dispersibility of the electrode active material. It is as follows. From these viewpoints, the weight average molecular weight of lignin sulfonic acid (salt) is preferably 3000 to 70000, more preferably 3000 to 50000, still more preferably 3000 to 40,000, particularly preferably 70000 to 30000, and extremely preferably 800 to 20000. Is. The weight average molecular weight of lignin sulfonic acid (salt) can be measured by the same method as the weight average molecular weight of bisphenol resin.

The content of lignin sulfonic acid (salt) may be 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more, based on the total mass of the negative electrode active material, and is 2% by mass or less. It may be 1% by mass or less or 0.5% by mass or less.

The negative electrode active material 15 may further contain a carbon material as an additive. That is, the negative electrode 11 may further contain a carbon material in the negative electrode active material 15. The carbon material may contain, for example, carbon black, graphite, etc., and preferably contains carbon black from the viewpoint of further suppressing liquid reduction. Examples of carbon black include furnace black, channel black, acetylene black, thermal black and Ketjen black.

The content of the carbon material may be 0.1% by mass or more, 0.5% by mass or more, 1.0% by mass or more, or 1.5% by mass or more based on the total mass of the negative electrode active material. It may be 5.5% by mass or less, 3.0% by mass or less, 2.5% by mass or less, or 2.0% by mass or less.

The negative electrode active material 15 may further contain barium sulfate, reinforcing short fibers and the like as additives. That is, the negative electrode 11 may further contain barium sulfate, reinforcing short fibers, and the like in the negative electrode active material 15. Examples of the reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers and the like. The content of barium sulfate may be, for example, 0.5% by mass or more and 3.0% by mass or less based on the total mass of the negative electrode active material. The content of the reinforcing short fibers may be, for example, 0.05% by mass or more and 0.3% by mass or less based on the total mass of the negative electrode active material.

The positive electrode active material 17 contains at least PbO ₂ as a Pb component, and may further contain a Pb component (for example, PbSO ₄ ) other than PbO ₂ and an additive, if necessary.

The content of the Pb component may be 90% by mass or more or 95% by mass or more, and may be 99% by mass or less or 98% by mass or less, based on the total mass of the positive electrode active material.

Examples of the additive include carbon materials (excluding carbon fibers) and reinforcing short fibers (acrylic fibers, polyethylene fibers, polypropylene fibers, polyethylene terephthalate fibers, etc.). Examples of the carbon material include carbon black and graphite. Examples of carbon black include furnace black, channel black, acetylene black, thermal black and Ketjen black.

The negative electrode side strap 18 for connecting the negative electrodes 11 to each other is formed of an alloy containing Pb and Sn (hereinafter referred to as “Pb—Sn-based alloy”) from the viewpoint of suppressing liquid reduction. The content of Pb is 85% by mass or more, 90% by mass or more, 92% by mass or more, 95% by mass or more, 98% by mass or more, or 99% by mass or more, based on the total mass of the Pb—Sn alloy. You can.

The Sn content is preferably 1% by mass or more, more preferably 2% by mass or more, and further, based on the total mass of the Pb—Sn alloy, from the viewpoint of improving the strength of the alloy and suppressing corrosion of the alloy. It is preferably 5% by mass or more. The Sn content is preferably 15% by mass or less, more preferably 10% by mass or less, still more preferably 8% by mass or less, based on the total mass of the Pb—Sn alloy, from the viewpoint of further suppressing liquid reduction. is there.

The Pb—Sn-based alloy may further contain other components such as As and Se in addition to Pb and Sn. The content (total amount) of the other components may be 0.1% by mass or more and may be 1% by mass or less based on the total mass of the Pb—Sn alloy.

The positive electrode side strap 19 connecting the positive electrodes 12 to each other may be formed of a Pb—Sn based alloy like the negative electrode side strap 18, and may be formed of a lead alloy other than the Pb—Sn based alloy. The positive electrode side strap 19 is preferably formed of the same alloy as the negative electrode side strap 18.

The lead-acid battery 1 described above is suitably used as a lead-acid battery for an idling stop system vehicle or a micro-hybrid vehicle. That is, one embodiment of the present invention is an application of the lead-acid battery 1 described above to an idling stop system vehicle or an application to a micro-hybrid vehicle.

The lead-acid battery 1 described above is manufactured by, for example, a manufacturing method including an electrode manufacturing step of obtaining electrodes (negative electrode and positive electrode) and an assembly step of assembling constituent members including the electrodes to obtain the lead-acid battery 1.

In the electrode manufacturing process, for example, the negative electrode current collector 14 holds the negative electrode active material paste, and then matures and dries to obtain an unmodified negative electrode 11, and the positive electrode current collector 16 holds the positive electrode active material paste. After that, the unmodified positive electrode 12 is obtained by aging and drying under the above-mentioned conditions.

The negative electrode active material paste contains, for example, lead powder, additives, solvent (eg water or organic solvent) and sulfuric acid (eg dilute sulfuric acid). The negative electrode active material paste is obtained, for example, by mixing a lead powder and an additive to obtain a mixture, and then adding a solvent and sulfuric acid to the mixture and kneading the mixture.

The positive electrode active material paste contains, for example, lead powder, additives added as needed, solvent (eg water or organic solvent) and sulfuric acid (eg dilute sulfuric acid). The positive electrode active material paste may further contain lead tan (Pb ₃ O ₄ ) from the viewpoint of shortening the chemical conversion time.

The lead powder is, for example, lead powder produced by a ball mill type lead powder maker or a barton pot type lead powder maker (in a ball mill type lead powder maker, a mixture of powder of the main component PbO and scaly metal lead). ).

The aging may be carried out in an atmosphere having a temperature of 35 to 85 ° C. and a humidity of 50 to 98 RH% for 15 to 60 hours. Drying may be carried out at a temperature of 45-80 ° C. for 15-30 hours.

In the assembly step, for example, the obtained negative electrode plate and positive electrode plate are laminated via the separator 13 and the current collecting portions of electrodes having the same polarity are welded with a strap to obtain an electrode group. This group of electrodes is arranged in an electric tank to produce an unchemical lead-acid battery. Next, dilute sulfuric acid is put into a non-chemical lead-acid battery, and a direct current is applied to form an electric tank. Subsequently, the lead storage battery 1 can be obtained by adjusting the specific gravity (20 ° C.) of the sulfuric acid after chemical conversion to an appropriate specific gravity of the electrolytic solution. The specific gravity (20 ° C.) of sulfuric acid used for chemical conversion may be 1.15 to 1.25. The specific gravity (20 ° C.) of sulfuric acid after chemical conversion is preferably 1.25 to 1.33, more preferably 1.26 to 1.30. The chemical conversion conditions and the specific gravity of sulfuric acid can be adjusted according to the size of the electrode. The chemical conversion treatment may be carried out in the assembly process or in the electrode manufacturing process (tank chemical conversion).

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following examples.

<Example 1>
(Preparation of electric tank)
An electric tank was prepared, which consisted of a box body with an open upper surface and whose inside was divided into six cell chambers by a partition wall.

(Preparation of positive electrode)
To the lead powder, 0.25% by mass of acrylic fiber (based on the total mass of lead powder) was added as a reinforcing short fiber and mixed dry. Next, 3% by mass of water and 30% by mass of dilute sulfuric acid (specific gravity 1.55) were added to the obtained mixture containing lead powder and kneaded for 1 hour to prepare a positive electrode active material paste. In the preparation of the positive electrode active material paste, dilute sulfuric acid (specific gravity 1.55) was added stepwise in order to avoid a rapid temperature rise. The blending amounts of water and dilute sulfuric acid are based on the total mass of lead powder and reinforcing short fibers.

An expand-type current collector produced by expanding a rolled sheet made of a lead alloy was filled with a positive electrode active material paste and then aged in an atmosphere of a temperature of 50 ° C. and a humidity of 98% for 24 hours. Then, it was dried at a temperature of 50 degreeC for 16 hours to prepare a positive electrode having an unmodified positive electrode active material.

(Preparation of negative electrode)
Lead powder was used as a raw material for the negative electrode active material. A mixture of sodium lignin sulfonate (manufactured by Nippon Paper Industries, Ltd., trade name: Vanillex N) and furnace black (manufactured by Cabot Corporation, trade name: Balkan XC) was added to lead powder and then dry-mixed. Next, water was added and then kneaded. Subsequently, dilute sulfuric acid having a specific gravity of 1.280 was added little by little and kneaded to prepare a negative electrode active material paste. The contents of sodium lignin sulfonate and furnace black were blended so as to be 0.2% by mass based on the total mass of the negative electrode active material after chemical conversion.

This negative electrode active material paste was filled in an expandable current collector produced by expanding a rolled sheet made of a lead alloy, and then aged in an atmosphere of a temperature of 50 ° C. and a humidity of 98% for 24 hours. Then, it was dried to prepare a negative electrode having an unmodified negative electrode active material.

(Battery assembly)
An unchemical negative electrode was inserted into a bag-shaped polyethylene separator. Next, five unchemical positive electrodes and six unchemical negative electrodes inserted into the bag-shaped separator were alternately laminated. Subsequently, the ears of electrodes having the same polarity were welded to each other by a cast-on-strap (COS) method to prepare a group of electrode plates. A Pb—Sn alloy (Pb content: 98% by mass, Sn content: 2% by mass) was used for the strap on the negative electrode side.

Six groups of these electrode plates were prepared and inserted into an electric tank to assemble an EN standard 12V cell battery (rank performance: 370, size: LN2). At this time, as the lid, a lid having an exhaust chamber of the above-described embodiment shown in FIGS. 3 to 5 was used. Then, a sulfuric acid solution having a specific gravity of 1.230 was injected, and chemical conversion was carried out at 10.4 A at a constant current for 20 hours. The specific gravity of the electrolytic solution (sulfuric acid solution) after chemical conversion was adjusted to 1.28 (20 ° C.).

<Example 2>
A lead-acid battery was produced in the same manner as in Example 1 except that scaly graphite (manufactured by Nippon Graphite Industry Co., Ltd., trade name: ACB) was used instead of furnace black in the production of the negative electrode. The content of scaly graphite was blended so as to be 1.5% by mass based on the total mass of the negative electrode active material after chemical conversion.

<Example 3>
Example 1 except that a bisphenol resin (condensate of bisphenol, aminobenzenesulfonic acid and formaldehyde, manufactured by Nippon Paper Co., Ltd., trade name: Vispers P215) was used in the production of the negative electrode instead of sodium lignin sulfonate. A lead storage battery was produced in the same manner as above. The content of the bisphenol resin was blended so as to be 0.2% by mass based on the total mass of the negative electrode active material after chemical conversion.

<Example 4>
In the production of the negative electrode, a lead storage battery was produced in the same manner as in Example 2 except that the same type and amount of bisphenol resin as in Example 3 was used instead of sodium lignin sulfonate.

<Comparative example 1>
Lead in the same manner as in Example 4 except that a Pb-Sb alloy (Pb content: 98% by mass, Sb content :: 2% by mass) was used instead of the Pb—Sn alloy for the negative electrode side strap. A storage battery was manufactured.

<Characteristic evaluation>
In the following, the lead-acid batteries of Examples and Comparative Examples were evaluated for liquid reduction suppression and DCA performance. The results are shown in Table 1. The evaluation of each performance was performed by making a relative evaluation with the measurement result of Comparative Example 1 as 100.

(Suppression of liquid reduction)
At an ambient temperature (water tank temperature) of 60 ° C., constant voltage overcharging was performed at 14.4 V for 42 days. The mass of the lead-acid battery before and after this charging was measured, and the suppression of liquid reduction was evaluated by comparing the mass difference (the amount of liquid reduction due to overcharging (liquid reduction amount)). It can be said that the smaller the amount of liquid reduction, the better the suppression of liquid reduction.

(DCA performance)
DCA performance evaluation was performed by an evaluation method according to the Dynamic Charge Evaluation (DCA) test described in BS EN50342-6: 2015, which is an EN standard. The average current value during charging standardized by the conversion formula is compared, and it can be said that the larger the average current value, the better the DCA performance.

1 ... lead-acid battery, 2 ... electric tank, 3 ... lid, 4 ... first lid, 5 ... second lid, 10 ... electrode group, 11 ... negative electrode, 12 ... positive electrode, 22 ... cell chamber, 400 ... Exhaust chamber components, D1, D2, D3, D4, D5, D6 ... Exhaust chamber, h ... Circulation hole.

Claims (7)

An electric tank with a cell chamber and an open top surface,
The electrode group and the electrolytic solution housed in the cell chamber,
With a lid that closes the opening,
A lead-acid battery in which the electrode group has a plurality of negative electrodes and a plurality of positive electrodes, and the plurality of negative electrodes are connected to each other by a strap formed of an alloy containing Pb and Sn. The lid is an exhaust gas formed between a first lid portion, a second lid portion provided on the first lid portion, and the first lid portion and the second lid portion. With a room,
The lead-acid battery according to claim 1, wherein the bottom wall of the first lid portion that separates the exhaust chamber and the cell chamber is provided with a reflux hole for refluxing the electrolytic solution into the cell chamber. The lead-acid battery according to claim 1 or 2, wherein the negative electrode contains a resin having a structural unit derived from a phenolic compound. The lead-acid battery according to claim 3, wherein the structural unit includes a structural unit derived from a bisphenol compound. The lead-acid battery according to claim 3, wherein the structural unit includes a structural unit derived from lignin. The lead-acid battery according to any one of claims 1 to 5, wherein the negative electrode contains a carbon material. The lead-acid battery according to claim 6, wherein the carbon material contains carbon black.