JPH05242883A - Secondary battery - Google Patents

Abstract

PURPOSE:To provide a maintenance-free secondary battery, without falling-off of a battery active material, excellent in electric over discharge durability, capable of preferably charging and discharging even at high current density. CONSTITUTION:Sulfate slurry is carried in a grid current collector consisting of lead-antimony holding lead-tin alloy felts as a positive electrode 2 and a negative electrode 3. Lead wool having a fiber diameter of 10mum or less is used as a current collecting material, thus constituting a battery. Consequently, it is possible to obtain a secondary battery remarkably excellent in durability against electric over charge and reverse discharge, capable of preferably electric charging and discharging even at high current density, having a long lifetime, and free from maintenance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery, and more particularly to a long-life secondary battery which can greatly reduce the maintenance work.

[0002]

2. Description of the Related Art Conventionally, lead-acid batteries have been known as inexpensive secondary batteries, and nickel-cadmium batteries, nickel-hydrogen batteries, etc. have been known as secondary batteries which are expensive but have few limitations in terms of durability and use. ing. Lead-acid batteries are overwhelmingly advantageous in price compared to other secondary batteries and are used as the mainstream of industrial batteries, including relatively large batteries, and their demand is still strong. is there.

However, the above conventional lead-acid battery has a serious problem that it cannot be recharged because the battery active material drops off when deeply discharged. Further, there are problems such as sulfation (sulfuric acid) due to over-discharge, corrosion of the positive electrode grid in a discharged state, generation of gas, etc., and maintenance work has been extremely complicated. Further, a conventional secondary battery, for example, a secondary battery using a lead fiber assembly as a current collector has a current collector surface area larger than that of a battery using a carbon fiber current collector because the fiber diameter is larger than 100 μm. For example, when the apparent current density is about 10 mA / cm ^{2, the} charge and discharge characteristics are good and the active material utilization rate is good.
If it is increased to about 00 mA / cm ² , there is a problem that good charge / discharge cannot be performed and a sufficient utilization ratio of the active material cannot be obtained. Such problems have hardly been solved yet, and this is the cause of stopping the expansion of applications of lead acid batteries. On the other hand, nickel-cadmium batteries, nickel-hydrogen batteries and the like are excellent in durability and the like, but there is a problem that the manufacturing cost becomes high.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to prevent the active material of the battery from falling off.
It is an object of the present invention to provide a maintenance-free, inexpensive secondary battery having excellent over-discharge durability and a long-life secondary battery capable of excellent charge / discharge even at a high current density.

[0005]

In order to achieve the above object, the first invention of the present application is a secondary battery using a fibrous conductive material made of lead or a lead alloy as a current collector,
The fibrous conductive material carries a battery active material, at least a part of which is a solid material.

[0006]

[Function] In a secondary battery using a fibrous conductive material made of lead or a lead alloy as a current collector, the fibrous conductive material carries or wraps a battery active material, at least a part of which is present as a solid material. As a result, the fibrous conductive material having a large surface area per unit volume is brought into contact with the active material which is a fine solid material, so that the effective contact area is increased and the active material is prevented from falling off. At the same time, the battery reaction will proceed promptly.

In the present invention, a fibrous conductive material made of lead or a lead alloy is used as the current collector. As the current collector, a noble metal-based current collector may be used from the viewpoint of positive electrode durability, but a lead-based current collector is used from the viewpoint of oxygen and hydrogen overvoltage, that is, gas is less likely to be generated.
Examples of the lead alloy include lead-antimony alloy, lead-calcium alloy, lead-tin alloy and the like.

In the present invention, examples of the battery active material, at least a part of which exists as a solid, include solid or slurry-like sulfuric acid-acidic lead compounds and vanadium compounds. Such a battery active material is usually used for the positive electrode and the negative electrode, but can be used only for the positive electrode. A second invention of the present application is a secondary battery using a fibrous conductive material made of lead or a lead alloy as a current collector, wherein the fiber diameter of the fibrous conductive material is 10 μm or less. Regarding secondary batteries.

In a secondary battery using a fibrous conductive substance made of lead or a lead alloy as a current collector, by setting the fiber diameter of the fibrous conductive substance to 10 μm or less,
Since the surface area of the current collector is increased, the charge / discharge current density can be increased not only when the electrolytic solution is circulated but also when it is stationary. In the present invention, as the fibrous conductive material made of lead or lead alloy, for example, lead wool, lead alloy wool, etc. are used, and the fiber diameter thereof is 10 μm or less, preferably 7 to 10 μm.

In the present invention, it is also possible to carry a battery active material, at least a part of which is a solid, on a fibrous conductive material having a fiber diameter of 10 μm or less. This makes it possible to obtain a secondary battery having excellent over-discharge characteristics and capable of performing excellent charge / discharge even at a high current density.

[0011]

EXAMPLES Next, the first invention of the present application will be described in more detail with reference to Examples. FIG. 1 is an explanatory diagram of a secondary battery showing an embodiment of the present invention. This battery comprises a positive electrode 1 and a negative electrode 2 made of lead felt carrying solid lead sulfate as a battery active material 4, a diaphragm 3 made of a glass mat disposed between the positive electrode 1 and the negative electrode 2, and the positive electrode. 1 and a lead lead wire 5 connected to the negative electrode 2 mainly.

In such a secondary battery, a charge / discharge cycle test is performed in which about 10 N-sulfuric acid is used as an electrolytic solution and the discharge end voltage is set to -1 V with a reverse polarity by starting from a completely discharged state of 100% lead sulfate. I went. Figure 2 shows a part of the result
Shown in. In the figure, it can be seen that the secondary battery has excellent discharge durability, with no reduction in battery capacity and life even after repeated charging and discharging several tens of times. Also, the same characteristics were exhibited even when the polarity was reversed.

According to this embodiment, no decrease in capacity due to charging / discharging is observed, and a large number of battery packs can be stacked via a bipolar partition plate to provide a high performance battery stack. The stacked battery configured in this way has the same SOC (depth of charge) between the individual cells due to repeated irregular charging and discharging, and even if there is a single cell that falls into an over-discharged state, the original state is restored. Returning to is easy. Therefore, by using the battery of the present embodiment, a large battery of bipolar stacking can be easily assembled, and by creating a large secondary battery with high input / output voltage, a new market for lead acid batteries can be created. It can also be developed.

Next, specific examples of the present invention will be described. Example 1 In the secondary battery having the configuration shown in FIG. 1, lead sulfate slurry (sulfate acidity) was applied to a lead grid current collector made of lead-antimony holding a lead-tin alloy felt having an average wire diameter of 70 μm as a positive electrode and a negative electrode. Each of the supported ones was used, and a cell mat was formed using a glass mat as a diaphragm, and a constant current charge / discharge cycle test was performed using about 10 N-sulfuric acid as an electrolytic solution to confirm overdischarge durability. Results are shown in FIG.

In FIG. 3, it can be seen that there is no tendency for the performance to deteriorate even when discharged to 0V. Further, even when reverse charging was performed, charging / discharging could be continued with the opposite polarity. Example 2 A single cell having the same configuration as in Example 1 except that the negative electrode was a lead oxide-supporting lead grid was subjected to a charge-discharge cycle test with a discharge end voltage of up to 1 V. No abnormalities such as decrease in capacity were observed.

Comparative Example 1 A charge / discharge test was performed at a discharge end voltage of 1 V in the same manner as in Example 1 except that both the positive electrode and the negative electrode were lead oxide-supported lead grids. After 20 cycles, it had almost no capacity. Example 3 A unit cell having the same configuration as in Example 1 was used, and the average wire diameter was 70 μm.
When a charge-discharge test (50 cycles) with a discharge end voltage of 0 V was performed on this laminated battery by using the above-described lead-antimony alloy felt, the laminated battery was laminated as shown in FIG. No abnormality was observed.

Example 4 A lead metal felt having an average wire diameter of 70 μm carrying vanadium sulfate (tetravalent vanadium) slurry as a positive electrode and a lead metal felt carrying vanadium sulfate (trivalent vanadium) slurry as a negative electrode were separated by a diaphragm. As a result, a battery was constructed using each of the cation exchange membranes, and a 50-cycle charge / discharge test was conducted with the discharge end voltage set to 0 V as in Example 1. No abnormality was found in cell resistance, battery capacity, or the like. ..

Example 5 A charge / discharge test was conducted in the same manner as in Example 1 except that a nickel hydroxide-supporting lead-antimony alloy felt was used as the positive electrode and an iron hydroxide-supporting lead-antimony alloy felt was used as the negative electrode. Good charging / discharging with a Coulomb efficiency of 98% or more could be performed.

Table 1 shows the structures of the batteries of Examples 1 to 5 and Comparative Example 1, charge / discharge conditions and the results thereof.

[0020]

[Table 1]

From Table 1, according to this embodiment in which the positive electrode and the negative electrode, or only the positive electrode, carries the battery active material, at least a part of which is solid, good charging and discharging can be performed without lowering the battery capacity. I can see that I was able to do it. Next, the second invention of the present application will be described in more detail with reference to Examples.
FIG. 5 is a partially exploded view showing the structure of the laminated secondary battery showing one embodiment of the present invention. In the figure, there is shown a unit cell in which a positive electrode 21 and a negative electrode 22 made of lead wool having a fiber diameter of 10 μm, which are respectively loaded in spacers 25, are laminated with a diaphragm 23 interposed therebetween. This unit cell includes a bipolar electrode partition plate 24. A plurality of layers are stacked through. Reference numeral 26 denotes a terminal plate, and the terminal plate 26 is provided with an inlet 27 and an outlet 29 for the positive electrode liquid, and an inlet 28 and an outlet 30 for the negative electrode liquid, respectively.

According to this embodiment, since the surface area of the electrode is increased by using the fibrous conductive substance having a fiber diameter of 10 μm or less as the electrode material, good charge / discharge can be performed even at a high current density. Next, specific examples of the present invention will be described. Example 6 An electrode plate made of lead wool having a fiber diameter of 10 μm and having a length of 100 mm, a width of 10 mm and a thickness of 5 mm was used as a positive electrode and a negative electrode, a lead sheet was used as a current collector, and an ion exchange membrane was used as a diaphragm. Current collector / positive electrode / diaphragm / negative electrode /
A battery consisting of a holding plate and a current collecting plate is formed, and 1.5 M vanadium (4 valences, 3 valences) of 2.5 M is used as the positive and negative electrode liquid
When a charge / discharge test was conducted using an acidic sulfuric acid solution and flowing this electrode solution at 3 ml / min and a current density of 100 mA / cm ² , the voltage efficiency was 93% and the Coulombic efficiency was 100%.

Example 7 A charge / discharge test was conducted in the same manner as in Example 6 except that the electrode liquid was kept stationary. As a result, the voltage efficiency was 85% and the Coulomb efficiency was 100%. Example 8 A charge / discharge test was conducted in the same manner as in Example 6 except that the current density was 50 mA / cm ² and the electrode solution was kept stationary. The voltage efficiency was 91% and the clone efficiency was 100%. ..

Comparative Example 2 A battery was constructed in the same manner as in Example 6 except that a lead felt having a fiber diameter of 100 μm or more was used as the positive electrode and the negative electrode. A voltage efficiency was 88.
%, The cloning efficiency was 99%. Comparative Example 3 A battery was constructed in the same manner as in Example 6 except that carbon felt having a fiber diameter of 150 to 170 μm was used as the positive electrode and the negative electrode, and a charge / discharge test was conducted. The voltage efficiency was 87%. The Coulombic efficiency was 98%, and some gas was generated from the negative electrode.

Table 2 shows the battery configurations, charging / discharging conditions and results of Examples 6-8 and Comparative Examples 2-3.

[0026]

[Table 2]

From Table 2, in the present example using lead wool having a fiber diameter of 10 μm as a current collector, the current density was 100 mA /
Even in cm ² , the Coulomb efficiency is 100%,
It can be seen that good charge and discharge could be performed.

[0028]

According to the first invention of the present application, there is provided a maintenance-free secondary battery having excellent durability against over-discharge and reverse charging, and having a long life from small size to large size. As with conventional lead-acid batteries, it can be obtained at low cost. In addition, the bipolar laminated battery in which the secondary battery of the present invention is laminated is destroyed even if there is a battery in which the charging / discharging depth varies among the individual batteries and the discharge voltage becomes equal to or lower than the allowable discharge voltage in the conventional battery during discharging. Therefore, the secondary battery has a very good life characteristic.

According to the second invention of the present application, by setting the fiber diameter of the fibrous conductive material as the current collector to 10 μm or less, the electrode area increases, so that good charge and discharge can be performed even at a high current density. It is possible to obtain a long-life secondary battery that can be used.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a secondary battery that is an embodiment of the present invention.

FIG. 2 is a diagram showing results of a charge / discharge test in one example of the present invention.

FIG. 3 is a diagram showing a result of a charge / discharge test in a specific example of the present invention.

FIG. 4 is an explanatory diagram showing the configuration of a bipolar electrode stack battery that is an embodiment of the present invention.

FIG. 5 is a partially exploded view showing the configuration of a laminated battery showing an example of the present invention.

[Explanation of symbols]

1 ... Positive electrode, 2 ... Negative electrode, 3 ... Diaphragm, 4 ... Battery active material, 5 ...
Lead lead wire, 11 ... Positive electrode side lead alloy felt, 12 ... Negative electrode side current collecting carrier material, 13 ... Positive electrode active material, 14 ... Negative electrode active material,
15 ... Bipolar plate (multipolar partition plate), 16 ... Diaphragm (separator), 17 ... Terminal plate, 21 ... Lead wool positive electrode, 22 ...
Lead wool negative electrode, 23 ... diaphragm, 24 ... bipolar partition plate, 25 ...
Spacer, 26 ... Terminal plate, 27 ... Positive electrode liquid inlet, 28 ... Negative electrode liquid inlet, 29 ... Positive electrode liquid outlet, 30 ... Negative electrode liquid outlet.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Zenji Kamio 1 Yawata Kaigan Dori, Ichihara City, Chiba Mitsui Engineering & Shipbuilding Co., Ltd. Chiba Works (72) Keiichi Watanabe 1 Hachiman Kaido Dori, Ichihara, Chiba Mitsui Engineering & Ships Co., Ltd. Company Chiba Office

Claims (2)

[Claims] 1. A secondary battery using a fibrous conductive material made of lead or a lead alloy as a current collector, wherein the fibrous conductive material carries a battery active material, at least a part of which is a solid material. Characteristic secondary battery. 2. A secondary battery using a fibrous conductive material made of lead or a lead alloy as a current collector, wherein the fibrous conductive material has a fiber diameter of 10 μm or less.