JPH04144058A - Sealed storage battery - Google Patents

Abstract

PURPOSE:To maintain securely a valve portion in closed condition for an extended period of time by securing a first permanent magnet to one of paired safety valve components while securing either a permanent magnet, magnetic body, or a metallic piece which causes attractive force to the first permanent magnet. CONSTITUTION:An electrode cluster 10 is arranged in a battery case 14 and its lug portion is extended outside. The case 14 is constituted by heat-welding the circumferences of plastic bodies 15, 16 of a laminate structure containing a magnetic layer 19 while leaving a portion 17 not welded. The portion 17 not welded constitutes a valve portion. Each of the plastic bodies 15, 16 is formed by laminating a plastic material layer 18, a magnetic body layer 19, and a plastic layer 20. The magnetic body layer 19 makes the plastic layers 15, 16 attract each other in the direction of their thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sealed storage battery, and particularly to improvements in a thin sealed storage battery.

(Prior art) Thin sealed storage batteries, which are used for portable devices, portable power sources, emergency power sources, etc., are made by joining two film-like or sheet-like synthetic resin bodies together by heat welding or the like. In conventional batteries, a group of electrode plates is placed in a battery case, where an unjoined part is formed around the joint of two synthetic resin bodies, or a small hole is formed in one of the two synthetic resin bodies. In either method, the valve is closed when the two safety valve components of the two synthetic resin bodies that make up the safety valve are in contact, and when they are apart. is the valve open state. However, when the valve is opened and closed repeatedly over a long period of time, the synthetic resin body undergoes a bending called creep deformation, and the safety valve section does not return to the closed state, resulting in poor airtightness.

When poor airtightness occurs, a problem arises in that external oxygen enters the battery and oxidizes the cathode plate.

Therefore, in order to prevent creep deformation as much as possible, Japanese Patent Application Laid-Open Nos. 62-133665 and 63-1
A battery as shown in Japanese Patent No. 74265 was proposed.

Figure 1 shows a schematic diagram of a sealed lead-acid battery disclosed in Japanese Patent Application Laid-Open No. 133665/1982. In this figure, in order to show the internal structure of the battery, of the two joined synthetic resin bodies, the synthetic resin body located on the front side in the drawing is depicted as being transparent.

In the battery disclosed in this publication, two plates of the electrode plate group 1 are made to face each other in parallel with no gap between them to form a safety valve part. A synthetic resin reinforcing material 5 is pasted onto at least one synthetic resin body 2 so as to cross the gas discharge path of the unwelded portion 3. This synthetic resin reinforcing material 5 increases the mechanical strength of the safety valve constituent portion of the synthetic resin body 2 constituting the safety valve portion, thereby suppressing the occurrence of creep deformation.

It shows. In this battery, the electrode plate group 1 is arranged between two synthetic resin bodies 2, the peripheral parts of the electrode plate group 1 are joined, and one (
A small hole 6 is formed in the synthetic resin body 2 (front) to constitute a safety valve part. The peripheral portion of the small hole 6 is discontinuously joined to the other synthetic resin body 2 to form a discontinuous welded portion 7, and this discontinuous welded portion 7 suppresses the occurrence of creep deformation.

[Problems to be Solved by the Invention] However, as in the former case, even if the safety valve component of the synthetic resin body is reinforced with the synthetic resin reinforcing material 5, the valve opening pressure of this type of battery is quite high, so As the period passes, creep deformation also occurs in the synthetic resin reinforcing material 5,
It was not possible to completely prevent airtightness caused by creep deformation.

In the latter case, since the discontinuous welded portion 7 is formed around the small hole 6, large deformation of the safety valve component can be prevented for a certain period of time. However, if the valve operation is repeated over a long period of time, creep deformation occurs in the safety valve component surrounded by the discontinuous weld portion 7, as in the conventional case. Therefore, even if the discontinuous welded portion 7 was provided, it was not possible to suppress the occurrence of creep deformation and prevent the occurrence of airtightness.

An object of the present invention is to provide a sealed storage battery that can reliably close a safety valve and prevent airtightness from occurring even when creep deformation occurs due to repeated valve operations over a long period of time. It is in.

Another object of the present invention is to provide a sealed storage battery in which the long-term reliability of the safety valve part can be improved and the moisture permeability and oxygen permeability of the battery case can be reduced.

[Means for Solving the Problems] In the sealed storage battery to be improved by the present invention, a group of electrode plates is arranged in a battery case formed by joining the peripheries of two sheet-like or film-like synthetic resin bodies. has been done. The safety valve portion is constructed by forming an unjoined portion at the joint portion around the two synthetic resin bodies or by forming a small hole in one of the two synthetic resin bodies.

In the invention according to claim 1, in this type of sealed storage battery, a first permanent magnet is fixed to one of a pair of safety valve component parts that constitute at least the safety valve part of the two synthetic resin bodies,
On the other hand, a second permanent magnet that generates an attractive force with the first permanent magnet or a magnetic body or a metal body that is attracted by the magnetic force of the first permanent magnet is fixed.

Here, the shapes of the first and second permanent magnets, the magnetic body, and the metal body and the state in which they are attached to the synthetic resin body are arbitrary. Claim 2
In the invention described in section 1, when the synthetic resin body has a laminate structure formed by laminating a plurality of sheet-like or film-like synthetic resin material layers, the first permanent magnet, the second permanent magnet, the magnetic The body or metal body is placed between a plurality of layers of synthetic resin material.

In the third aspect of the invention, the synthetic resin body has a laminate structure in which a magnetic layer is arranged between a plurality of sheet-like or film-like synthetic resin material layers. The magnetic layer of at least one synthetic resin body is magnetized so as to attract the other synthetic resin body.

[Function] When the internal pressure of the battery rises, the pair of safety valve constituent parts of the two synthetic resin bodies that make up the safety valve part separate and the safety valve part opens, and when the internal pressure of the battery falls below a certain pressure, the elastic limit range of the battery case is reached. Inside, contact between the pair of safety valve components is restored again. Opening of the safety valve.

Due to repeated valve closing, creep deformation occurs in the pair of safety valve components of the synthetic resin body that constitutes the safety valve section.

According to the invention of claim 1, the first permanent magnet is fixed to one of the pair of safety valve components, and the second permanent magnet or the second permanent magnet that exerts an attractive force between it and the first permanent magnet is fixed to the other of the pair of safety valve components. If a magnetic or metal object that is attracted by the magnetic force of the permanent magnet 1 is fixed, even if creep deformation occurs in the safety valve components, the pair of safety valve components will be attracted to each other by the magnetic force of the permanent magnet after the valve is opened. They make contact and the valve becomes closed. Therefore, it is possible to reliably prevent airtightness from occurring due to creep deformation.

According to the invention of claim 2, a synthetic resin body having a laminate structure is used, and the first permanent magnet, the second permanent magnet, the magnetic body, or the metal body are made of a plurality of synthetic resin materials constituting the synthetic resin body. If placed between the layers, the first permanent magnet etc. can be reliably fixed to the synthetic resin body.

Further, according to the invention of claim 3, a synthetic resin body having a laminar foot structure in which a magnetic layer is arranged between a plurality of sheet-like or film-like synthetic resin material layers is used, and at least one synthetic resin body When the magnetic material layer is magnetized so as to attract the other synthetic resin material, as in the invention of claim 1,
It is possible to prevent the occurrence of airtightness in the safety valve section, and the following effects occur. In other words, since the magnetic material layer, which has lower moisture permeability and oxygen permeability than the synthetic resin material layer, surrounds the electrode plate group, it prevents moisture in the electrolyte from permeating from the battery case to the outside, and also prevents electricity from entering from the outside. It is possible to prevent oxygen from entering the tank and improve battery characteristics.

Furthermore, the long-term reliability of the safety valve is maintained even without the need for reinforcing materials to prevent deformation of the battery case material or the placement of discontinuous joints in the battery case, making it possible to reduce these parts and the number of man-hours required for their arrangement. , productivity will also improve.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of the main parts of an embodiment of the sealed storage battery of the present invention, and the synthetic resin body located at the front in the drawing is shown transparently to show the internal structure. FIG. 2 is a sectional view taken along the line ■--■ in FIG.

In these figures, 1o is the electrode group, and the electrode group 10
A separator 13 is arranged between a cathode plate 11 and an anode plate 12. The electrode plate group 1o is housed in the battery case 14 so that the ears of the electrode plates are exposed to the outside. The battery case 14 includes a part of the periphery of the laminated synthetic resin bodies 15 and 16 containing the magnetic material [19] that is not welded (unbonded part).
They are joined by heat welding so that 17 remains. This unwelded portion 17 constitutes a safety valve portion.

The synthetic resin bodies 15 and 16 each have a synthetic resin material layer 18 (made of polyethylene terephthalate) from the outer surface side.
In this example, the thickness is 12 μm) (hereinafter referred to as "rPET layer"), and the magnetic material 1'1g19 (3 μm) made of new KStA.
, a synthetic resin material layer 20 made of unstretched polypropylene (
It has a laminate structure in which 62 μm thick) (hereinafter referred to as rcPPJif) are laminated. Note that the PET layer 18
The magnetic layer 19 and the CPP layer 20 may be bonded by thermal welding or may be bonded using an adhesive.

The new KSE used in this example is a ferromagnetic material with a
00 Oersted (Oe) (=1.51 and 106A
/m), a coercive force of 800i:Oe) is obtained. In this embodiment, the magnetic layer 19 of the synthetic resin bodies 15 and 16 is laminated in a rectangular manner. is slightly higher, but this is due to the thickness of the magnetic layer.

It can be adjusted as appropriate by changing the magnetic material, magnetization conditions, and length of the unwelded portion 17.

In this embodiment, the magnetized magnetic layers 19 of the synthetic resin bodies 15 and 16 constitute first and second permanent magnets. In the above embodiment, the synthetic resin bodies 15 and 16
Permanent magnets are placed on both sides, but only one synthetic resin body is equipped with a permanent magnet, and the other synthetic resin body is equipped with a magnetic material (such as a paramagnetic material) or a metal material that is attracted by the magnetic force of the permanent magnet. (for example, iron) may be provided.

In order to confirm the effects of the above-mentioned embodiment, in the prior art injection molding, the synthetic resin reinforcing material was provided only on one synthetic resin body. Conventional product B is a sealed to lead-acid battery shown in FIG. These conventional battery containers have a PE7 layer (thickness 12μm), a polyvinylidene chloride layer (thickness 15μm), and a CPP layer (thickness 62μm).
A synthetic resin body having a laminate structure formed by laminating m) was used. The batteries used in the test were 2V-0, 6Ah batteries, and 10 of each were subjected to a valve opening/closing cycle test, and the average value of the 10 batteries was plotted.

In the valve opening/closing cycle test, a hole is made at the bottom of the battery and a glass tube is connected to it, and N2 gas is introduced into and out of the battery cell through this glass tube at a flow rate of 30 mA/min, increasing and decreasing the pressure repeatedly. The changes in valve opening pressure and airtightness were investigated for each cycle.

After about 500 cycles, the valve opening pressure became O and a leakage failure occurred (the point where the leakage failure occurred is indicated by the symbol N).
Invention will try to solve this problem first! ! $! As explained in detail in the title, the creep deformation that occurred in the synthetic resin body had progressed to the extent that the valve could no longer be closed, so 17 was placed, so it had higher rigidity than conventional products A and B, and as a result, the initial valve opening was delayed. The pressure is at its highest. And, no significant decrease in valve opening pressure is seen until k, 800 cycles ago. After around 800 cycles, the valve opening pressure decreases significantly.

This means that the synthetic resin material layers (18 and 20) open the valve.

This is because as the valve is repeatedly closed, it begins to weaken and creep deformation occurs in the synthetic resin material layer. In the battery of the present invention, even in such a case, since the magnetized magnetic bodies 119 in the synthetic resin bodies 15 and 16 attract each other, the valve operation is performed by the magnetic force of the magnetic body N19.

As the cycle progresses further, the synthetic resin material layer (1 day and 20
), the valve action is almost eliminated, and the valve opening pressure is approximately 30 mm.
The valve opening pressure of Hg remained constant thereafter. This approximately 30a+m
The valve opening pressure of Hg is the valve opening pressure obtained by the magnetic force of the magnetized magnetometer. Regarding the battery tube of this example, 50
A valve opening/closing cycle test was conducted up to 00 cycles, but no seal failure was observed.

In the above embodiment, in order to provide a permanent magnet in at least one synthetic resin body, a magnetic layer is placed entirely between the synthetic resin material layers of the laminated synthetic resin body. The setting and size of the permanent magnets are arbitrary as long as they do not occur. Therefore, in the present invention, the first permanent magnet is fixed to one of the pair of safety valve component parts constituting at least the safety valve part of the two synthetic resin bodies, and an attractive force is applied between the first permanent magnet and the other part. It is sufficient to fix a magnetic body or a metal body that is attracted by the generated magnetic force of the second permanent magnet or the first permanent magnet.

It should be noted that a small portion of the synthetic resin body (in the type of battery shown in Tomoyasu Figure 5, this is the part located in a predetermined range surrounding the small hole 6). It may be fixed using an agent.

[Effects of the Invention] According to the invention of claim 1, a first permanent magnet is fixed to one of a pair of safety valve components, and a second permanent magnet that generates an attractive force between the first permanent magnet and the other first permanent magnet is fixed to one of a pair of safety valve components. Since the permanent magnet or the magnetic body or metal body that is attracted by the magnetic force of the first permanent magnet is fixed, even if creep deformation occurs in the safety valve component, after the valve is opened, the pair of safety valve components will be fixed by the magnetic force of the permanent magnet. The parts can be brought into contact with each other and a closed state can always be formed. Therefore, according to the present invention, it is possible to reliably prevent airtightness from occurring due to creep deformation.

According to the invention of claim 2, a synthetic resin body having a laminate structure is used, and the first permanent magnet, the second permanent magnet, the magnetic body or the metal body are made of a plurality of synthetic resin sheets constituting the synthetic resin body. When placed between the material layers, there is an advantage that the first permanent magnet etc. can be reliably fixed to the synthetic resin body.

According to the third aspect of the invention, a synthetic resin body having a laminate structure in which a magnetic layer is arranged between a plurality of sheet-like or film-like synthetic resin material layers is used, and at least one of the synthetic resin bodies Since the magnetic material layer is magnetized so as to attract the other synthetic resin material, there is an advantage that the occurrence of airtightness in the safety valve section can be reliably prevented, similar to the invention of claim 1. In addition, since the magnetic material layer, which has lower moisture permeability and oxygen permeability than synthetic resin materials, surrounds the electrode plate group, it is possible to prevent moisture in the electrolyte from permeating from the tank to the outside. It is possible to prevent oxygen from entering the battery case, thereby improving battery characteristics.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a schematic configuration of a sealed storage battery according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 shows the results of a valve opening/closing cycle test. 4 is a diagram showing a schematic configuration of an example of a conventional sealed lead-acid battery, and FIG. 5 is a diagram showing a schematic configuration of another conventional sealed lead-acid battery. 4...Battery container, 18°0...Synthetic resin material layer,...Magnetic layer.

Claims (3)

[Claims] (1) A group of electrode plates is arranged in a battery case formed by joining the periphery of two sheet-like or film-like synthetic resin bodies, and the above-mentioned 2
A sealed storage battery in which a safety valve part is formed by forming an unjoined part at the joint part around two synthetic resin bodies or by forming a small hole in one of the two synthetic resin bodies, A first permanent magnet is fixed to one of a pair of safety valve component parts constituting at least the safety valve part of the synthetic resin body, and a second permanent magnet that generates an attractive force between the other part and the first permanent magnet. Alternatively, a sealed storage battery characterized in that a magnetic body or a metal body attracted by the magnetic force of the first permanent magnet is fixed. (2) The synthetic resin body has a laminate structure formed by laminating a plurality of sheet-like or film-like synthetic resin material layers, and the first permanent magnet, the second permanent magnet,
2. The sealed storage battery according to claim 1, wherein a magnetic body or a metal body is arranged between the plurality of synthetic resin material layers. (3) A group of electrode plates is placed in a battery case made by welding the peripheries of two sheet-like or film-like synthetic resin bodies with some unwelded parts left, and a safety valve is placed in the unwelded parts. In the sealed storage battery, the synthetic resin body has a laminate structure in which a magnetic layer is arranged between a plurality of sheet-like or film-like synthetic resin material layers, and at least A sealed storage battery characterized in that the magnetic layer of one synthetic resin body is magnetized so as to attract the other synthetic resin body.