JPH0562707A - Stacked type nickel-hydrogen battery - Google Patents

Abstract

PURPOSE:To increase energy density larger than conventional device by improving a group constitution. CONSTITUTION:Positive electrodes, consisted mainly of a nickel oxide, and negative electrodes, consisted mainly of a hydrogen storage alloy, are alternately stacked, electrode plates at both sides of the group are designed to be negative electrodes. The capacity of the negative electrodes at both sides of the group is designed to range from 44 to 55%. The energy density of a battery can be increased than conventional ones by this constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated nickel-hydrogen storage battery used in applications requiring large capacity such as electric vehicles.

[0002]

2. Description of the Related Art Lead batteries and alkaline batteries are widely used as storage batteries for various power sources. Among them, small batteries have been used for various portable devices and large batteries have been used for industrial purposes because they can be expected to have high reliability and can be made compact and lightweight.

As the positive electrode of this alkaline storage battery, although an air electrode, a silver oxide electrode and the like are partially taken up, a nickel electrode is used in most cases. The characteristics of this nickel electrode have improved from the pocket type to the sintered type, and it has become possible to seal the battery and expand its applications.

On the other hand, as the negative electrode, in addition to cadmium, zinc, iron, hydrogen, etc. are targeted, but at present, the cadmium electrode is mainly used. However, in recent years, a hydrogen storage alloy electrode capable of reversibly storing and releasing hydrogen has attracted attention,
Many proposals have been made for manufacturing methods. This hydrogen storage alloy electrode has a theoretical capacity density larger than that of a cadmium electrode, and does not have the deformation like a zinc electrode or the formation of dendrites. Therefore, it has a long life, no pollution, and a high energy density negative electrode for alkaline storage batteries. Is expected as.

A nickel-hydrogen storage battery using such a hydrogen-absorbing alloy electrode as a negative electrode has already been put into practical use in a cylindrical sealed type, but its use is limited to portable electronic devices and the like because of its small battery capacity. .. Stacked type batteries are attracting attention for those requiring a larger capacity, such as those for electric vehicles.

[0006]

However, even though such a conventional laminated hydrogen storage alloy electrode has a large theoretical capacity density, a laminated nickel-hydrogen storage battery using it as a negative electrode is currently used as a hydrogen storage alloy electrode. The energy density expected from the theoretical capacity density of is not obtained.

The present invention solves such a problem, and an object thereof is to provide a laminated nickel-hydrogen battery having a larger energy density than before by improving the group structure.

[0008]

In order to solve such a problem, the present invention provides a positive electrode containing nickel hydroxide as a main component,
Laminated nickel having a negative electrode mainly composed of a hydrogen storage alloy, a separator and an electrolytic solution, and having a group structure in which the positive electrode plates and the negative electrode plates are alternately laminated, and the electrode plates at both ends of the group are negative electrode plates. -In a hydrogen storage battery, the capacity of each of the negative plates at both ends of the group is 45 to 55% of the capacity of the other negative plates.
It was made to be.

The negative electrode plate is an electrode plate using foamed nickel as a core, and the negative electrode plates at both ends of the group have the same electrode plate area as other negative electrode plates and the electrode plate thickness is 45 to 55%. It was done like this.

Further, the negative electrode plates other than both ends of the group are electrode plates using foamed nickel as a core, and the negative electrode plates at both ends of the group are sintered type or paste coated type electrode plates. Is.

[0011]

In the laminated nickel-hydrogen storage battery of the present invention, the capacity of each of the negative electrode plates at both ends of the group is about 1/2 of the capacity of the other negative electrode plates, so that the weight of the negative electrode plates at both ends of the group is reduced. The thickness of the electrode plate can be reduced. Therefore, the laminated nickel-hydrogen storage battery of the present invention can have a higher energy density than the conventional battery.

[0012]

EXAMPLE A laminated nickel-metal alloy according to an example of the present invention will be described below.
The hydrogen storage battery will be described.

A foamed nickel plate having a length of 90 mm and a width of 72 mm filled with a paste prepared by mixing nickel hydroxide powder and metallic cobalt powder with water is used as a positive electrode plate.
A negative electrode plate was prepared by filling a paste in which mNi _3.55 Mn _0.4 Al _0.3 Co _0.75 was mixed with a 3 wt% polyvinyl alcohol aqueous solution. A 0.15 mm-thick polyamide nonwoven fabric was used as the separator, and an aqueous potassium hydroxide solution having a specific gravity of 1.30 was used as the electrolyte.

First, an example of the laminated nickel-hydrogen storage battery of the present invention will be described. 10 positive plates, 11 negative plates
The negative electrode plate is one of the other negative electrode plates.
In order to make the capacity of 2, both positive and negative electrodes were considered to be 10, and the thicknesses of the positive electrode plate and the negative electrode plate were determined so that the thickness of the electrode plate group was 95% of the width of the battery case. And the positive electrode plate is 0.87m thick
The negative electrode plate was pressed to m to a thickness of 0.72 mm, and each of the electrode plates was inserted into a separator having a bag shape. Also,
A negative electrode plate in which the filling amount of the hydrogen storage alloy was ½ of the capacity of the negative electrode plate was pressed to a thickness of 0.36 mm and inserted into a bag-shaped separator. 10 such positive electrode plates,
Nine negative electrode plates having a thickness of 0.72 mm and two negative electrode plates having a thickness of 0.36 mm were alternately laminated so that both ends were negative electrode plates having a thickness of 0.36 mm. Width of this plate group is 30mm
3 mm), length 83 mm, height 125 mm
After adding 4.9 ml of electrolyte, the structure was sealed. The battery weight was 783.4 g.

Next, as a comparative example, 10 positive plates and 11 negative plates were used, and the thickness of the electrode plate group was 95% of the width of the battery case.
The thicknesses of the positive electrode plate and the negative electrode plate were determined so that The positive electrode plate has a thickness of 0.81 mm and the negative electrode plate has a thickness of 0.68 mm.
Then, each electrode plate was inserted into a separator formed in a bag shape. Ten such positive plates and one negative plate 1
One sheet was positively and negatively stacked alternately so that both ends were negative electrode plates. Insert this plate group into a battery case of the same size as above,
After adding 0.2 ml of electrolyte, a closed structure was obtained. The battery weight in this case was 776.0 g.

These batteries were subjected to 1 at 3 A in an atmosphere of 20 ° C.
The battery was charged for 5 hours, left for 1 hour, and then discharged at 6 A to 1.0V. Then, after aging at 45 ° C. for 48 hours, the battery was charged again at 3 ° C. for 15 hours in an atmosphere of 20 ° C., left for 1 hour and then discharged at 6 A to 1.0 V. The discharge capacities of this second cycle were compared. The battery of the comparative example was 32.6 Ah, while the battery of the present invention was 34.8 Ah. Comparing the energy densities, the battery of the comparative example had a weight energy density of 50.4 Wh / kg and the volume energy density of 134.5 Wh / l, but the batteries of the present invention had 53.3 Wh / kg and 143.5 Wh, respectively. The weight energy density was increased by 5.8% and the volumetric energy density was increased by 6.7%.

In the case of a laminated type group structure, since only one side of the negative electrode plates at both ends of the group faces the positive electrode plate, it is considered that 1/2 of the active material does not participate in charge / discharge. Therefore, the capacity does not decrease even if the capacity of the negative electrode plates at both ends of the group is set to 1/2 of the capacity of the other negative electrode plates. If the capacity of the negative electrode plate is halved, the weight of the electrode plate is reduced and the weight energy density is increased. Further, since the thickness of the electrode plate can be made small, the battery case can be made thin and the volumetric energy density also becomes large.

In this example, the battery of the present invention was compared with the battery of the comparative example by using the same size battery case, but the battery of the present invention has a higher energy density for the same reason as described above. ..

In this embodiment, an example in which the capacity of the negative electrode plates at both ends is set to 1/2 of that of the other negative electrode plates has been described.
Similar effects were obtained even with a negative electrode capacity of 45 to 55%.

Further, even if the negative electrode plates at both ends of the group are formed by sintering type electrode plates or paste coating type electrode plates, the electrode plate weight can be reduced and the energy density can be increased.

[0021]

In the laminated nickel-metal hydride storage battery of the present invention, the capacity of the negative electrode plates at both ends of the group is 45 times that of the other negative electrode plates.
Since it is ˜55%, it is possible to reduce the weight of the negative electrode plates on both ends of the group and to reduce the thickness of the electrode plates. Therefore, the laminated nickel-hydrogen storage battery of the present invention can have a higher energy density than conventional batteries.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tadao Kimura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yoshinori Toyoguchi, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A positive electrode mainly composed of nickel hydroxide, a negative electrode mainly composed of hydrogen storage alloy, a separator separating the positive electrode and the negative electrode, and an electrolytic solution, wherein the positive electrode plate and the negative electrode plate are alternated. A laminated nickel-hydrogen storage battery in which the electrode plates at both ends of the group are negative electrode plates, and the capacity of the negative electrode plates at both ends of the group is 45 to 45% of that of other negative electrode plates. 55% stacked nickel-metal hydride storage battery. 2. The negative electrode plate is an electrode plate using foamed nickel as a core, and the negative electrode plates at both ends of the group have the same electrode plate area as the other negative electrode plates and the electrode plate thickness is 45 to 55%. The stacked nickel-hydrogen storage battery according to claim 1. 3. A negative electrode plate other than both ends of the group is an electrode plate using foamed nickel as a core, and negative electrode plates at both ends of the group are sintering type or paste coating type electrode plates. Stacked nickel-hydrogen storage battery.