JP6791326B2 - Lead-acid battery - Google Patents

Description

The present invention relates to a lead storage battery.

Lead-acid batteries are widely used for industrial and consumer purposes due to their reliability and low price, and there is a particularly large demand for lead-acid batteries for automobiles (so-called batteries).

In recent years, as an effort to protect the environment and improve fuel efficiency, the development of an idling stop start (hereinafter abbreviated as ISS) vehicle that stops the engine when the vehicle is stopped and restarts when the vehicle is started has been accelerated. The lead-acid battery mounted on the ISS vehicle frequently starts and stops the engine, so that the number of large current discharges increases at the time of starting, and it is necessary to supply electric power to the electrical components while the vehicle is stopped, which increases the discharge load. The vehicle is charged by the alternator, but because it is powered by the engine, it stops when the vehicle is stopped. Due to these ISS-specific usage conditions, the lead-acid battery is used in a state where it is not completely charged, that is, in a partially charged state (PSOC: Partial State Of Charge).

When a lead-acid battery is used in the PSOC state, a problem that does not occur in the conventional fully charged state occurs. It is known that this is a so-called ear thinning phenomenon in which the current collecting portion (ear portion) of the negative electrode lattice is discharged and the thickness of the current collecting portion is reduced. When the ear thinning phenomenon occurs, the resistance of the current collector increases, the charge / discharge characteristics of the lead-acid battery deteriorate, and the cycle life performance deteriorates.

In Patent Document 1, a lead-tin alloy layer is provided on the surface of the selvage portion of the negative electrode lattice, and the negative electrode active material after being fully charged contains 0.25 to 0.75% by mass of carbon. A technique for suppressing thinning is disclosed.

Republished WO 2010/032782

The negative electrode plate is produced by filling a negative electrode lattice with an active material paste. The active material paste is prepared by mixing an organic additive, carbon, and barium sulfate with lead powder, adding water and dilute sulfuric acid, and kneading. Carbon or carbon material is added as a conductive auxiliary agent.

Normally, in a lead storage battery, carbon is contained in an amount of 0.1 to 0.3% by mass with respect to the negative electrode active material after being fully charged. When the amount of carbon is increased by 0.5% by mass or more, the active material paste becomes hard, it becomes difficult to fill the negative electrode lattice, filling defects occur, and the yield decreases.

In order to make the active material paste have an appropriate hardness, there is a method of increasing the amount of water added during the kneading to increase the amount of water. However, in the negative electrode plate having an increased amount of paste water, the active material shrinks due to the water being removed in the aging and drying steps after filling, and the surface of the negative electrode plate is cracked. In such a state, the active material will fall off in the subsequent battery assembly process. Therefore, it is not preferable to increase the amount of water in the paste.

An object of the present invention is to alleviate ear thinning in the negative electrode current collector without changing the paste specifications.

Therefore, the present invention has the following configuration in order to solve the above problems.

The first invention is in a lead-acid battery in which a group of electrode plates in which positive electrode plates and negative electrode plates are alternately laminated via a separator is housed in an electric tank, the total surface area of the positive electrode plates is S, and the volume of the electrode plates is V. When S / V is 3.95 cm ^-1 or more, and when the amount of active material of the positive electrode plate is X and the amount of active material of the negative electrode plate is Y, X / Y is 1.35 or more. And.

The second invention, in the first invention, has an S / V of 4.2 cm ^-1 or more and an X / Y of 1.45 or more.

According to the present invention, it is possible to alleviate the thinning of the ears of the negative electrode current collector without changing the paste specifications, and it is possible to obtain a lead storage battery having excellent cycle life characteristics.

It is a figure which shows the electrode plate group of this invention. It is a figure which shows the expanded lattice body. It is a figure which shows the positive electrode plate. It is a figure which shows the microporous polyethylene sheet. It is a figure which puts the negative electrode plate in a bag separator. It is a figure which shows the electric tank. It is a figure which shows the battery.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(Lattice body)
As the lattice body, the expanded lattice body 1 shown in FIG. 2 was used, which was expanded by making a cut in a lead-calcium-tin alloy sheet. The dimensions excluding the current collector 2 are 145 mm in width, 115 mm in height and 1.5 mm in thickness for the positive electrode, and 145 mm in width, 115 mm in height and 1.3 mm in thickness for the negative electrode. The current collector 2 is also called an ear portion.

(Positive plate)
Lead powder with a degree of oxidation of 70% prepared by the ball mill method is kneaded with water and dilute sulfuric acid, and a slurry obtained by mixing and reacting lead tan with a degree of lead conversion of 90% with dilute sulfuric acid to prepare an active material paste. .. The active material paste is filled in the expanded lattice body 1 for a positive electrode, and after aging and drying by a conventional method, the positive electrode plate 3 shown in FIG. 3 is obtained. In FIG. 2, the portion filled with the active material paste is the filling portion 4.

(Negative electrode plate)
Carbon powder, lignin powder, and barium compound powder are added and mixed as additives to the lead powder having an oxidation degree of 70% produced by the ball mill method. Subsequently, water and dilute sulfuric acid are added and kneaded to prepare an active material paste. The active material paste is filled in the expanded lattice for the negative electrode, and aged and dried by a conventional method to obtain a negative electrode plate.

(Bag separator)
FIG. 4 shows a microporous polyethylene sheet 6. Ribs 7 of a separator are provided on one side of the polyethylene sheet 6 in the longitudinal direction, the thickness of the base portion of the polyethylene sheet 6 is 0.2 mm, and the total thickness including the ribs 7 is 0.8 mm. The polyethylene sheet 6 is cut into a length of 235 mm and a width of 152 mm and folded in half. Subsequently, both side portions are mechanically sealed or heat welded, and processed into a bag separator 8 as shown in FIG.

(Strap formation and electrode plate group)
As shown in FIG. 5, the negative electrode plate 5 is put in the bag separator 8, and 7 positive electrode plates and 8 negative electrode plates wrapped in the bag separator are alternately laminated. The current collecting portions 2 of the positive electrode and the negative electrode are welded by the cast-on-strap method to form the welded portion shown in FIG. 1, that is, the strap 9, and the electrode plate group 10 is obtained.
As the alloy composition of the strap 9, a lead-antimony alloy or a lead-tin alloy can be used.

(Electric tank)
FIG. 6 shows a polypropylene battery case 11. The electric tank 11 is divided into 6 sections by a partition wall 12, and a cell chamber 13 is provided. The electrode plate group 10 is also called a cell, which has a battery capacity of only 2V. In order to drive an electric component for an automobile by stepping up or lowering a DC voltage of 12V, six electrode plate groups 10 are connected in series to make 2V × 6 = 12V. Therefore, six cell chambers 13 are required.
A plurality of ribs 14 are provided on both sides of the partition wall 12 of the electric tank 11 and on the inner wall surfaces of both end surfaces of the electric tank 11 in the height direction of the electric tank 11. The rib 14 has a role of appropriately pressurizing the electrode plate group.

(Battery production)
The electrode plate group 10 is inserted into the cell chamber 13 of the electric tank 11, and the straps 9 of the adjacent electrode plate groups are welded through partition wall welding. A polypropylene lid 15 is heat-welded to the battery case 11 to produce the battery 16 shown in FIG. 7. In the electrode plate group 10 housed in the cell chambers at both ends shown in FIG. 7, a polar column having a columnar portion attached to the strap 9 is formed. This is for connecting to the positive electrode terminal 17A and the negative electrode terminal 17B projecting from the lid 15.

Subsequently, dilute sulfuric acid, which is an electrolytic solution, is injected from the injection port 18 corresponding to the cell chamber 13 of the lid 15 and energized at an ambient temperature of 40 ° C. and a current of 25 A for 20 hours to form an electric tank. After chemical conversion of the battery case, the electrolyte level was adjusted to produce an 80D23 type battery specified by JISD5301.

(Total surface area of positive electrode plate, volume of electrode plate group)
The total surface area of the positive electrode plate 3 is the surface area of a cell, which is the smallest unit of a lead storage battery, that is, a portion of the electrode plate group 10 housed in the cell chamber 13 that is involved in power generation of the positive electrode plate 3. It is a total. In FIG. 3, the number of positive electrode plates constituting the electrode plate group 10 is added to the total surface area of the front and back surfaces of each positive electrode plate excluding the current collecting portion 2 and the unfilled portion of the active material paste. It is multiplied.
That is, the total surface area S of the positive electrode plate per electrode plate group 10 is given by (Equation 1) from FIG. In the present invention, [cm ² ] is used as the unit of S.
S = (filling part width x filling part height) x 2 x number of positive electrode plates ... (Equation 1)
The volume of the electrode plate group 10 is a portion of each part of the electrode plate group housed in one cell, which is the smallest unit of the lead-acid battery, which does not include the current collector 2 and the strap 9, and is the electrode plate of the bag separator 8. It is an apparent volume calculated from the external dimensions including the height of the protruding portion not in contact with the surface and the ribs 7 on both end faces of the electrode plate group 10.

That is, the volume V of the electrode plate group 10 is given by (Equation 2) from FIG. In the present invention, [cm ³ ] is used as the unit of V.
V = electrode plate group width x electrode plate group thickness x electrode plate group height ... (Equation 2)

(Amount of active substance)
The amount of active material is the total amount of active material after chemical conversion of the electric tank, and is a value obtained by subtracting the total mass of the lattice body from the total mass of the plates.

That is, the amount of positive electrode active material is obtained by multiplying the amount of active material of one positive electrode plate 3 by the number of positive electrode plates constituting the electrode plate group 10. The amount of negative electrode active material is obtained by multiplying the amount of active material of one negative electrode plate 4 by the number of negative electrode plates constituting the electrode plate group 10.

(Evaluation test)
The following test is carried out on the battery in an environment of 25 ° C.
(A) Constant current discharge at a current of 59 A for 59 seconds.
(B) Constant current discharge for 1 second at a current of 300 A.
(C) Constant current / constant voltage charging for 1 minute at a constant current of 14.0 V and a limit current of 100 A.
(D) Charging and discharging are repeated with (a) to (c) as one cycle.
The battery life is determined when the current for the first second in (a) becomes 7.2 V or less.

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

(Example 1)
In the 80D23 type battery, the S / V was manufactured as follows.
From (Equation 1), S = (14.5 × 11) × 2 × 7 = 2233 [cm ² ]
From (Equation 2), V = 14.5 × 3.36 × 11.6 = 565 [cm ³ ]
Therefore, the S / V is 3.95 cm ^-1 .
X / Y was prepared to be 1.35.

(Example 2)
In Example 1, a battery having an S / V of 3.95 cm ^-1 and an X / Y of 1.4 was produced.

(Example 3)
In Example 1, a battery having an S / V of 3.95 cm ^-1 and an X / Y of 1.45 was produced.

(Example 4)
In Example 1, a battery having an S / V of 3.95 cm ^-1 and an X / Y of 1.47 was produced.

(Example 5)
In Example 1, a battery having an S / V of 4.1 cm ^-1 and an X / Y of 1.35 was produced.

(Example 6)
In Example 1, a battery having an S / V of 4.1 cm ^-1 and an X / Y of 1.4 was produced.

(Example 7)
In Example 1, a battery having an S / V of 4.1 cm ^-1 and an X / Y of 1.45 was produced.

(Example 8)
In Example 1, a battery having an S / V of 4.1 cm ^-1 and an X / Y of 1.47 was produced.

(Example 9)
In Example 1, a battery having an S / V of 4.2 cm ^-1 and an X / Y of 1.35 was produced.

(Example 10)
In Example 1, a battery having an S / V of 4.2 cm ^-1 and an X / Y of 1.4 was produced.

(Example 11)
In Example 1, a battery having an S / V of 4.2 cm ^-1 and an X / Y of 1.45 was produced.

(Example 12)
In Example 1, a battery having an S / V of 4.2 cm ^-1 and an X / Y of 1.47 was produced.

(Example 13)
In Example 1, a battery having an S / V of 4.3 cm ^-1 and an X / Y of 1.35 was produced.

(Example 14)
In Example 1, a battery having an S / V of 4.3 cm ^-1 and an X / Y of 1.4 was produced.

(Example 15)
In Example 1, a battery having an S / V of 4.3 cm ^-1 and an X / Y of 1.45 was produced.

(Example 16)
In Example 1, a battery having an S / V of 4.3 cm ^-1 and an X / Y of 1.47 was produced.

(Comparative Example 1)
In Example 1, a battery having an S / V of 3.95 cm ^-1 and an X / Y of 1.33 was produced.

(Comparative Example 2)
In Example 1, a battery having an S / V of 4.1 cm ^-1 and an X / Y of 1.33 was produced.

(Comparative Example 3)
In Example 1, a battery having an S / V of 4.2 cm ^-1 and an X / Y of 1.33 was produced.

(Comparative Example 4)
In Example 1, a battery having an S / V of 4.3 cm ^-1 and an X / Y of 1.33 was produced.

(Comparative Example 5)
In Example 1, a battery having an S / V of 3.9 cm ^-1 and an X / Y of 1.35 was produced.

(Comparative Example 6)
In Example 1, a battery having an S / V of 3.9 cm ^-1 and an X / Y of 1.4 was produced.

(Comparative Example 7)
In Example 1, a battery having an S / V of 3.9 cm ^-1 and an X / Y of 1.45 was produced.

(Comparative Example 8)
In Example 1, a battery having an S / V of 3.9 cm ^-1 and an X / Y of 1.47 was produced.

(Comparative Example 9)
In Example 1, a battery having an S / V of 3.9 cm ^-1 and an X / Y of 1.33 was produced.

Table 1 shows the results of the number of cycles when the life test of these lead-acid batteries was performed.

It can be seen that Examples 1 to 16 using the present invention have an excellent number of life cycles. When each battery was disassembled at the number of life cycles of Comparative Example 9 in order to verify the life mode, the thickness of the current collecting portion (ear portion) was the thinnest in Comparative Example 9 and the thickest in Examples 11, 12, 15, and 16. It was thick. From this, it can be said that in this embodiment, the ear thinning of the negative electrode current collector can be alleviated and the cycle life characteristic is improved.

Although it is not clear, it is considered that the reason for these is that the ratio (S / V) of the total surface area of the positive electrode plate to the volume of the electrode plate group is 3.95 cm ^-1 or more, which moderates the increase in overvoltage during charging. .. Further, it is considered that the ratio of the positive electrode active material to the negative electrode active material (X / Y) is 1.35 or more, so that lead sulfate produced in the negative electrode ear portion is completely reduced to metallic lead. In particular, it is considered that the resistance decreases and the overvoltage decreases further as the surface area of the positive electrode plate increases, so that the S / V is preferably 4.2 cm ^-1 or more. Further, it is considered that the negative electrode is reduced at a sufficiently low potential by increasing the amount of active material of the positive electrode, and therefore, it is preferable that the X / Y is 1.45 or more.

Although the upper limit is not specified in the present invention, the upper limit of S / V is preferably 5.2 cm ^-1 and the upper limit of X / Y is preferably 1.6 for practical use of the lead storage battery.

Although the upper limit of S / V is not specified in the present invention, the upper limit is preferably 5.2 cm- ¹ for practical use of the lead storage battery.

In the above embodiment, the thickness of the electrode plate was adjusted to change the S / V, but the S / V could also be changed by changing the thickness of the expanding lattice body 1, the base thickness of the polyethylene sheet 6, and the height of the rib 7. You can change it.

1. 1. Expanded lattice, 2. Current collector, 3. Positive electrode plate, 4. Filling part, 5. Negative electrode plate, 6. Polyethylene sheet, 7. Rib, 8. Bag separator, 9. Strap, 10. Plate group, 11. Electric tank, 12. Septum, 13. Cell room, 14. Rib, 15. Lid, 16. Battery, 17A. Positive electrode terminal, 17B. Negative electrode terminal, 18. Injection port.

Claims (2)

In a lead-acid battery in which a group of electrode plates in which positive electrode plates and negative electrode plates are alternately laminated via a separator is stored in an electric tank, when the total surface area of the positive electrode plates is S and the volume of the electrode plates is V, S / V is less 3.95Cm ^-1 or 5.2 cm ^-1, and an active material of the positive electrode plate X, when the amount of active material of the negative electrode plate was Y, X / Y is 1.35 or more A lead-acid battery characterized by being. The lead storage battery according to claim 1, wherein the S / V is 4.2 cm ^-1 or more and the X / Y is 1.45 or more.