JP3498374B2 - Method for producing current collector for lead-acid battery and positive electrode plate for lead-acid battery - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current collector for a lead storage battery and a method for manufacturing a positive electrode plate for a lead storage battery.

[0002]

2. Description of the Related Art A general current collector used for a lead-acid battery such as a sealed lead-acid battery is formed of a grid body made of Pb or Pb alloy. In the paste type lead-acid battery plate, the active material paste is filled on the surface of the current collector to form an active material layer. When this type of lead-acid battery is used as a distributed type emergency power source and trickle charge is applied to the sealed lead-acid battery, the current collector of the positive electrode plate reacts with the electrolytic solution to form a current collector. Corrosion occurs along the grain boundaries of the alloy. In particular, when a lead alloy containing Ca (hereinafter referred to as Pb-Ca alloy, etc.) such as Pb-Ca alloy is used as a lattice, the crystal grains are likely to become fine and the grain interface increases, so that the current collection is increased. The body is easily corroded. When such corrosion progresses, the current collector of the positive electrode plate greatly expands and the active material falls off, and the battery reaches the end of its service life early. So we made collectors using various alloys,
It was studied to improve the corrosion resistance of the current collector. However, even in this case, the adhesion between the current collector and the active material layer is reduced, the self-discharge or the amount of reduced liquid is increased, the current collector strength is reduced, and the current collector productivity is reduced. There was a problem of doing. Therefore, J. Electrochem. Soc. V
ol. 139 (1992), BaPb
It has been proposed to form a lead acid salt film composed of a complex oxide such as O ₃ or SrPbO _{3 on} the surface of the current collector. Since such lead acid salt has high acid resistance and corrosion resistance, it is possible to prevent corrosion of the current collector. Conventionally, a film made of lead acid salt has been formed on the surface of the current collector as follows.
First, a current collector such as a lattice made of Pb or a Pb alloy and a conductor (counter electrode) such as lead are immersed in a dilute sulfuric acid solution. Then, the positive electrode terminal of the power source is connected to the current collector, the negative electrode terminal of the power source is connected to the conductor (counter electrode), and an electric current is passed to anodize the current collector, whereby PbO ₂ is formed on the surface of the current collector. To form a film. Then, add a hydroxide salt such as Ba (OH) ₂ to P
After coating on the bO ₂ film, PbO is baked at high temperature.
By reacting ₂ with a hydroxide salt, BaP is formed on the entire surface of the current collector.
A film of a double oxide such as bO ₃ was formed.

[0003]

The film thus formed is entirely formed on the surface of the current collector. However, this coating has uneven thickness and cannot completely cover the surface of the current collector. Therefore, a part where the particle interface is not covered with this film is generated. In particular, since the corrosion progresses along the grain interface, the corrosion resistance is significantly reduced when the film is not reliably formed on the grain interface of the current collector.

Further, such a double oxide film has poor adhesion to the active material layer, and when a film is formed on the entire surface of the current collector as in the conventional current collector, the current collector and the active material layer are not formed. There is a problem that the adhesiveness with the material layer is reduced and the active material falls off from the current collector.

An object of the present invention is to provide a current collector for a lead storage battery, which can prevent the active material from falling off from the current collector and can surely suppress the corrosion of the crystal grain interface.

Another object of the present invention is to provide a method for easily producing a positive electrode plate for a lead storage battery, which can prevent the active material from falling off from the current collector and can surely suppress the corrosion of the crystal grain interface. Especially.

[0007]

Means for Solving the Problems The present invention is directed to a lead-acid battery current collector made of lead or lead alloy, only on the crystal grain boundaries of the surface of the current collector R _x M _y O _z ( R and M form a complex oxide film composed of a metal element and x, y, and z are positive integers. The mixed _{oxide, R x Pb y O z (} R
Is preferably a metal salt, and x, y, and z are positive integers). Further, as the lead acid salt, a perovskite-type lead acid salt made of RPbO ₃ (R is a positive integer) is preferable.
Perovskite type lead oxide has a stable crystal structure and thus has high corrosion resistance.

In order to manufacture a positive electrode plate for a lead storage battery in which a lead acid salt is formed only on the crystal grain interface of the current collector, first, a current collector material made of a lead alloy containing the metal element R is heated and collected. After the metal element R is segregated at the crystal grain interface of the current collector material to form a current collector, an active material layer containing PbO ₂ as a main component is formed on the current collector. The term “segregation” used herein means that the concentration of the metal element R in the crystal grain interface portion becomes high. When the current collector material is heated and cooled, the concentration of the metal element R at the crystal grain interface increases. Then, the current collector on which the active material layer is formed is heated, and the metallic element R and PbO _{2 on} the surface of the current collector are heated.
By reacting the door, forming R _x Pb _y O _z (R represents a metal element, x, y, z are positive integers) only on the crystal grain boundaries of the surface of the current collector a coating of lead acid salt comprising To do. By doing so, the lead acid salt can be easily and reliably formed only on the crystal grain interface of the current collector.

Further, for a lead-acid battery current collector made of a lead alloy containing a metal having acid resistance and oxidation resistance, even if the metal is segregated at the crystal grain interface of the current collector, the Can suppress corrosion.

[0010]

According to the present invention, R _x M _y O _z (R and M are metallic elements, x, y, and
z is a positive integer) When a film of multiple oxides is formed,
Corrosion of crystal grain interfaces can be reliably suppressed. In addition, since the active material layer is directly formed on the current collector except the crystal grain interface on the current collector, the active material layer is formed in close contact with the current collector. Therefore, it is possible to prevent the active material from falling off from the current collector as in the conventional case.

[0011]

【Example】

(Example 1) A positive electrode plate using the current collector of this example was manufactured as follows. First, Pb-0.06 wt% Ca-
A current collector material composed of a lattice was produced by casting using 0.04 wt% Sr alloy as a raw material. Next, this collector material 1
By heating at 70 ° C. for 16 hours, strontium (Sr) was segregated at the crystal grain interface of the current collector material to prepare a current collector for a lead storage battery. The preferable heating temperature is 150 to 200 ° C., and the preferable heating time is 15 to 20 hours. Then, the active material paste was filled in the current collector by a usual method, and then matured and dried to form an active material layer containing PbO ₂ as a main component on the current collector. Next, after the formation of the active material layer, the current collector is dried at 220 ° C. for 16 hours, and PbO _{2 on} the surface of the current collector reacts with Sr on the crystal grain interface to crystallize the surface of the current collector. 0.8 μm thick Sr only on the grain interface
A perovskite-type lead salt film made of PbO ₃ was formed to complete the positive electrode plate. The preferred heating temperature for drying is 200 to 250 ° C., and the preferred heating time is 15 to 250 ° C.
20 hours. The preferable thickness of the SrPbO ₃ film is 0.5 to 3 μm. The positive electrode plate of the present embodiment has a structure in which an active material layer 2 is formed on the surface 1a of a current collector 1 as shown in FIG. The current collector 1 is made of an alloy in which crystal particles 3 are accumulated. Strontium (Sr) is segregated at the mutual interface 3a of the crystal grains 3 ..., and the coating 4 of SrPbO ₃ is formed only on the crystal grain interface 3a of the surface 1a of the current collector 1.

(Embodiment 2) A positive electrode plate using the current collector of this embodiment has Pb-0.0 instead of Pb-Ca-Sr alloy.
A current collector material was made from a 6 wt% Ca-0.2 wt% Ba alloy as a raw material, and the others were made in the same manner as in Example 1. The thickness was formed on the crystal grain interface on the surface of the current collector. 2μ
A perovskite-type lead acid salt film made of m 2 BaPbO ₃ is formed. In this example, the preferable temperature for heating the current collector material is 150 to 200 ° C., and the preferable heating time is 15 to 20 hours. The preferred heating temperature for drying the current collector having the active material layer formed thereon after completion of chemical conversion is 180 to 250 ° C., and the preferred heating time is 15 to 20 hours. The preferable thickness of the BaPbO ₃ coating is 0.5 to 3 μm.

(Embodiment 3) A positive electrode plate using the current collector of this embodiment is made of a Pb-Ca-Sn alloy collector material.
The active material layer is formed on a current collector in which Sn is segregated at the crystal grain interface by heating at 50 to 200 ° C. for 15 to 20 hours. In this current collector, Sn is segregated at the crystal grain interface, but no lead salt film is formed.

(Conventional Example 1) The positive electrode plate using the current collector of this conventional example is a positive electrode plate in which an active material layer is simply formed on a current collector material. This positive electrode plate did not segregate strontium (Sr) at the crystal grain interface of the current collector, and did not form a lead acid salt film on the crystal grain interface on the surface of the current collector. I made it in the same way.

(Conventional Example 2) A positive electrode plate using the current collector of the present conventional example is a positive electrode plate in which an active material layer is formed on a current collector having a 20 μm thick SrPbO ₃ film formed on the entire surface.
To prepare the current collector of this conventional example, first, the same current collector material as in Example 1 and a lead conductor (counter electrode) were immersed in a dilute sulfuric acid solution. Then, connect the positive electrode terminal of the power supply to the current collector material,
The negative electrode terminal of the power source is connected to the electric conductor (counter electrode), and a current is passed to anodize the current collector, whereby P
A film of bO ₂ was formed. Next, Sr (OH) ₂ is added to Pb
PbO ₂ after being applied on the O ₂ film and baked at high temperature
Reacts with Sr (OH) ₂ to form S on the entire surface of the current collector.
It was completed by forming a film of rPbO ₃ .

Next, the positive electrode plates of Examples 1 to 3 and Conventional Examples 1 and 2 were combined with ordinary paste type negative electrode plates, respectively,
Four of each of the 2.65 Ah-12V sealed lead-acid batteries were made. And using each battery, charging voltage 13.65V,
A constant voltage overcharge trickle life test was performed at an ambient voltage of 71 ° C. FIG. 2 shows the measurement result. From this figure, it can be seen that the battery using the positive electrode plate of Example 1 has a service life extended to about 1.5 times that of the battery using the positive electrode plate of Conventional Example 1. When the batteries using the positive electrode plates of Example 1 and Conventional Example 1 that had reached the end of their life were disassembled, there was almost no softening of the positive electrode active material, and it was confirmed that the active material fell off due to the extension of the current collector. . Further, in all the batteries, the extension and corrosion of the current collector were about the same. From this, it can be seen that the positive electrode plate of Example 1 has a current collector corrosion rate of about 1/1.
It can be seen that it is 5 times slower, or about 2/3 times slower. Also, from this figure, it can be seen that the battery using the positive electrode plate of Example 2 has a life that is approximately 1.2 times as long as that of the battery using the positive electrode plate of Conventional Example 1.

In each of the above embodiments, an example of forming a film of BaPbO ₃ and SrPbO ₃ was shown.
O _3, Sr ₂ SnO _4, may be formed a film of another double oxide such as Ca ₂ PbO _4. To form a film of BaSnO ₃ on the crystal grain interface on the surface of the current collector, first, a lead alloy containing Ba and Sn is heated to form B on the crystal grain interface.
A and Sn are segregated to prepare a current collector. Then, an active material layer is formed on the current collector and then heated. Sn becomes SnO ₂ at the stage of forming an active material, and this SnO ₂ reacts with Ba to become BaSnO ₃ .

In each of the above examples, Sr or Ba segregated at the crystal grain interface was reacted with PbO ₂ to form a lead salt film on the crystal grain interface on the surface of the current collector. Even if a metal such as Sr or Ba is segregated at the crystal grain interface without forming a lead acid salt film, the effect of preventing corrosion can be obtained.

The structure of some of the inventions described in the specification will be shown below.

(1) A current collector material composed of a lattice made of a Pb-Ca-Sn alloy as a raw material is heated at 150 to 200 ° C for 15
After heating for 20 hours, Sn is added to the crystal grain interface of the current collector material.
A method for producing a current collector for a lead storage battery, characterized in that:

(2) A current collector material composed of a lattice made of a Pb-Ca-Sr alloy as a raw material is used at 150 to 200 ° C. for 15 minutes.
~ 20 hours heating, S in the crystal grain interface of the current collector material
After segregating r to form a current collector, the current collector is filled with an active material paste, aged and dried to form Pb on the current collector.
An active material layer containing O ₂ as a main component is formed, and the current collector on which the active material layer is formed is heated at 200 to 250 ° C. for 15 to 20 hours after completion of chemical conversion to obtain PbO _{2 on the} surface portion of the current collector. And Sr on the crystal grain interface are reacted to form a perovskite-type lead acid salt film of SrPbO ₃ having a thickness of 0.5 to ₃ μm on the crystal grain interface on the surface of the current collector. Manufacturing method of positive electrode plate for lead acid battery. (3) A current collector material composed of a lattice made of a Pb-Ca-Ba alloy as a raw material is heated at 150 to 200 ° C for 15 to 20 hours to segregate Ba at the crystal grain interface of the current collector material to collect the material. After forming the current collector, the current collector was filled with an active material paste, aged and dried to form an active material layer containing PbO ₂ as a main component on the current collector, and the active material layer was formed. After the formation of the current collector, the current collector is heated at 180 to 250 ° C. for 15 to 20 hours to cause PbO _{2 on} the surface of the current collector to react with Ba on the interface of the crystal particles to form an interface of the crystal particles on the surface of the current collector. A method for manufacturing a positive electrode plate for a lead storage battery, which comprises forming a perovskite-type lead salt film made of BaPbO ₃ having a thickness of 0.5 to ₃ μm on the positive electrode plate.

[0022]

According to the present invention, R _x M _y O _z (R and M are metallic elements, only on the crystal grain interface on the surface of the current collector,
Since a complex oxide film composed of (x, y, z is a positive integer) is formed, it is possible to prevent the active material from falling off from the current collector, and it is possible to reliably suppress the corrosion of the crystal grain interface. Therefore, the battery life during trickle charging (trickle use) can be extended.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a positive electrode plate of this example.

FIG. 2 is a diagram showing constant voltage overcharge trickle life performance of the battery used in the test.

[Explanation of symbols]

1 Current Collector 2 Active Material Layer 3 Crystal Particle 3a Crystal Particle Interface 4 SrPbO ₃ Film

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 60-77358 (JP, A) JP 2-152165 (JP, A) JP 3-116657 (JP, A) JP 61- 224271 (JP, A) Tokuyo HEI 4-505072 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01M 4/20 H01M 4/66

Claims (5)

(57) [Claims] 1. A lead or lead-acid battery current collector made of lead alloy, only on the crystal grain boundaries of the surface of the current collector R _x M _y O
_{A current} collector for a lead storage battery, wherein a film of a double oxide composed of _z (R and M are metal elements, x, y, and z are positive integers) is formed. 2. The lead oxide as claimed in claim 1, wherein the double oxide is R _x Pb _y O _z (R is a metal element, and x, y, and z are positive integers). Current collector for lead acid battery. 3. The current collector for a lead storage battery according to claim 2, wherein the lead acid salt is a perovskite-type lead acid salt made of RPbO ₃ (R is a metal element). 4. A current collector material made of a lead alloy containing a metal element R is heated to segregate the metal element R at the crystal grain interface of the current collector material to form a current collector. An active material layer containing PbO ₂ as a main component is formed on the current collector, and the current collector on which the active material layer is formed is heated to generate the metal element R and PbO on the surface of the current collector. ₂ and reacts with R _x P only on the crystal grain interface on the surface of the current collector.
b _y O _z (R represents a metal element, x, y, z are positive integers) process for producing a positive electrode plate for a lead storage battery, which comprises forming a coating of lead acid salt comprising. 5. A lead storage battery current collector made of a lead alloy containing a metal having acid resistance and oxidation resistance, wherein the metal is segregated at a crystal grain interface of the current collector. Current collector for storage battery.