JPH0582158A - Sealed rectangular alkaline storage battery - Google Patents

Abstract

PURPOSE:To provide a sealed rectangular alkaline storage battery having a stable battery performance for long-period charge and discharge cycles with which decrease of an electrolyte content inside a separator by swelling of a positive pole with the charge and discharge cycles can be covered. CONSTITUTION:Spacers 8 having a water retentivity, an expansion property, and alkaline are disposed at two positions between an inner cell of a battery jar 1 and an electrode group 9 of a sealed rectangular alkaline storage battery, so the spacers 8 also act as reservoirs for electrolyte, and that swelling of positive pole plates 5 is absorbed by its expansion property. Decrease of an electrolyte content inside separators 7 by swelling of the positive pole plates 5 occuring after a long-period repetition of charge and discharge cycles can thus be covered, and a stable battery performance can be achieved through the long-period charge and discharge cycles. There shall preferably be a relational expression of TPX0.2XS/2<=TS<=TPX0.5XS/2 satisfied among a spacer thickness TSmm, a positive pole plate initial thickness TPmm, and the number S of positive pole plates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed prismatic alkaline storage battery, and more particularly, it covers a decrease in the electrolytic solution content in a separator due to the swelling of the positive electrode associated with a charge / discharge cycle and provides stable battery performance in a long-term charge / discharge cycle. The present invention relates to a sealed prismatic alkaline storage battery.

[0002]

2. Description of the Related Art As a conventional sealed alkaline storage battery, there are three types: a cylindrical type in which an electrode plate and a separator are spirally wound, a flat type in which a pellet active material is used, and a square type in which an electrode plate and a separator are laminated. It is divided into

Among them, the sealed prismatic alkaline storage battery has been mainly used in recent years mainly for small-sized headphone stereos from the viewpoint of effective use of space, which is a problem of the cylindrical shape. In addition, a large-capacity closed prismatic battery has been developed for an electric vehicle, and has an advantage that it has excellent low temperature characteristics and high rate discharge characteristics, which are features of alkaline storage batteries.

[0004]

In recent years, as the capacity and energy density of batteries have increased, high-porosity substrates and electrode plates with high packing density have been used. The swelling after the passage tended to be remarkable. As a result, the electrolytic solution in the separator is moved to the positive electrode side, and there is a problem that the battery performance is deteriorated due to the decrease in the electrolytic solution content.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a sealed prismatic alkaline storage battery having stable battery performance even in a long-term charge / discharge cycle.

[0006]

[Means for Solving the Problem] To solve this problem
The sealed prismatic alkaline storage battery of the present invention comprises a plurality of positive and negative electrode plates.
Have a structure in which
In sealed prismatic alkaline storage battery,
Water retention, stretchability, and alkali resistance with the group
Two spacers are arranged. Moreover, this
Pacer thickness T _Smm and the initial thickness T of the positive electrode plate_Pmm, and positive electrode
The number of plates S is T_P× 0.2 × S / 2 ≦ T_S≤T_PIt is preferable that the relational expression x0.5xS / 2 is satisfied.

[0007]

[Function] By arranging a spacer having water retention, stretchability, and alkali resistance between the inner wall of the battery of the closed prismatic alkaline storage battery and the electrode group, this spacer serves as a reservoir for the electrolytic solution, In addition, its elasticity serves to absorb the swelling of the positive electrode plate. Therefore, it is possible to cover the decrease in the content of the electrolytic solution in the separator due to the swelling of the positive electrode, which is observed after a long-term charge / discharge cycle, and to bring out stable battery performance in the long-term charge / discharge cycle.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sealed prismatic alkaline storage battery according to an embodiment of the present invention will be described below with reference to the drawings.

As a nickel electrode for the positive electrode, a unit weight of 650
Nickel hydroxide powder as an active material and metallic cobalt powder were mixed with water into a foamed nickel porous body of g / m ² to form a paste, and the mixture was filled with a dry material, dipped in a fluororesin dispersion after being pressurized by drying. A dried electrode plate was used. The electrode plate had a width of 142 mm, a length of 153 mm, and an average thickness of 0.7 mm.

The negative electrode is made of the same foamed nickel porous body as the positive electrode, and is MmNi _3.55 Mn _0.4 Al having 400 meshes.
_The one filled with a hydrogen storage alloy having a composition of _0.3 Co _0.75 (Mm is a mesh metal) was used. The filling was performed in a paste form using a solution in which 0.4 wt% of polyvinyl alcohol was dissolved. The width and length of the electrode plate were the same as those of the positive electrode, and the thickness was 0.6 mm on average.

Next, 6 pieces of the above-mentioned paste-like nickel positive electrode and 7 pieces of hydrogen-absorbing alloy negative electrode were combined and alternately laminated on a separator via a polyamide non-woven fabric having a thickness of 0.3 mm to form an electrode group. Further, a polypropylene spacer having water retention, stretchability and alkali resistance was arranged between this electrode group and the inner wall of the polypropylene battery case to form a closed prismatic battery having a nominal capacity of 120 Ah. The thickness of the spacer was 0.63 mm calculated from the swelling ratio of 30% of the positive electrode after 1000 cycles, and it was arranged at two positions on both sides of the electrode group.

In FIG. 1, the inner wall of the battery case 1, the nickel positive electrode 5 and the hydrogen storage alloy negative electrode 6 are respectively separated by a separator 7
A spacer 8 is provided between the electrode group 9 and a plurality of electrode groups 9 which are alternately laminated with the spacer 8 interposed therebetween. Reference numeral 4 is a lead whose one end is connected to the nickel positive electrode 5 or the hydrogen storage alloy negative electrode 6, and the other end is connected to the positive or negative pole column 3 provided on the battery case lid 2 that seals the upper part of the battery case 1. There is.

The electrolytic solution used was a caustic potash aqueous solution having a specific gravity of 1.30, in which 5 g / 1 of lithium hydroxide was dissolved.

A battery having two spacers 8 provided between the inner wall of the battery case 1 and the electrode group 9 was provided as A, and a battery having one spacer 8 provided as a comparison was not provided at all as B. Let the battery be C.

These batteries were charged at a current of 0.1 C for 15 hours and then discharged at a current of 0.2 C until the battery voltage became 1.0 V, which was repeated 1000 times to examine the change in battery capacity. The result is shown in FIG.

From FIG. 2, the battery A of the embodiment is the comparative battery B,
Long-term charge / discharge cycle characteristics are superior to C. From this result, water retention, stretchability, and
By arranging a spacer having alkali resistance, the decrease in the electrolytic solution content in the separator due to the swelling of the positive electrode that occurs after a long-term charge / discharge cycle has been covered, and as a result, the battery characteristics during a long-term charge / discharge cycle are stabilized. It became clear to let. It was also clarified that it is more effective to provide the spacer between the inner wall of the battery case and the electrode group at two locations on both sides rather than at one location on one side.

In this embodiment, the thickness of the spacer is calculated as the positive electrode swelling rate of 30%, but the swelling rate is 20 to 50.
Even if calculated from the range of%, that is, the thickness T of the spacer
_S mm, the positive electrode plate initial thickness T _P mm, and the number of positive electrode plates S satisfy the relational expression of T _P × 0.2 × S / 2 ≦ T _S ≦ T _P × 0.5 × S / 2. , A similar effect is obtained. Although the nickel-hydrogen storage battery is used in this embodiment, the same effect can be obtained by using other sealed prismatic alkaline storage batteries (nickel-cadmium storage battery, nickel-zinc storage battery).

[0018]

As is apparent from the above description of the embodiments, according to the sealed prismatic alkaline storage battery of the present invention, a spacer having water retention, stretchability and alkali resistance between the inner wall of the battery case and the electrode group. By disposing, the decrease in the electrolytic solution content in the separator due to the swelling of the positive electrode that occurs after the long-term charge / discharge cycle has passed can be stabilized and the battery characteristics during the long-term charge / discharge cycle can be stabilized.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a sealed prismatic alkaline storage battery according to an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the number of charge / discharge cycles and the battery capacity of the sealed prismatic alkaline storage batteries of one example and the comparative example of the present invention.

[Explanation of symbols]

 1 Battery Case 5 Nickel Positive Electrode 6 Hydrogen Storage Alloy Negative Electrode 7 Separator 8 Spacer 9 Electrode Group

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hajime Sari 1006 Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A sealed prismatic alkaline storage battery having a plurality of positive electrode plates and a plurality of negative electrode plates, which are alternately laminated with separators in between, wherein water retention, elasticity, and elasticity are provided between the inner wall of the battery case and the electrode group. And 2 spacers with alkali resistance
A sealed prismatic alkaline storage battery with a structure that is placed in one place. 2. The spacer thickness T _S mm, the positive electrode plate initial thickness T _P mm, and the number of positive electrode plates S are: T _P × 0.2 × S / 2 ≦ T _S ≦ T _P × 0.5 × The sealed prismatic alkaline storage battery according to claim 1, wherein the relational expression S / 2 is satisfied.