JPH10284037A - Sealed type storage battery provided with safety valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly exhaust gas and safely use without anxiety by eliminating a clogging caused by thermally fused materials of a safety valve opened. SOLUTION: A sealed type accumulator is provided with a sealing plate 1 in which a safety valve 2 opening when internal pressure of a battery case becomes higher than set pressure is incorporated. The sealing plate 1 is constituted of a body plate 1A and an electrode cap 1B which close the opening part of a sheath-can. In the sealing plate 1, a valve element 4 for closing a valve hole 1a opened in the body plate 1A is incorporated. The valve element 4 closes the valve hole 1a when internal pressure of a battery is lower than set pressure and opens the valve hole 1a when internal pressure of the battery becomes higher than set pressure. The electrode cap 1B is provided with a thin line part 11 which is broken by gas of abnormal pressure and an exhaust port 3 exhausting gas which is flowed in by passing the valve hole 1a. The exhaust port 3 is provided by being connected with the thin line part 11. By making these exhaust port 3 and thin line part 11 as cut-off parts, the electrode cap 1B is broken.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed storage battery having a safety valve that opens when the internal pressure of a battery rises abnormally to prevent the battery from being damaged.

[0002]

2. Description of the Related Art A sealed storage battery such as an alkaline storage battery has a safety valve provided on a sealing plate for closing an opening of an outer can.
The safety valve is opened when gas is generated inside the battery and the internal pressure rises abnormally, releasing the gas inside the battery to the outside of the battery case and preventing the battery case from bursting due to the internal pressure. I do. If the safety valve is not provided, when the internal pressure rises abnormally, the sealing portion that hermetically closes the opening of the outer can will burst. This is because the strength of the sealing part is weaker than other parts. When the sealing plate of the battery case is damaged by being pushed by the high-pressure gas, the impact may be considerably large as compared with the case where the sealing plate is pushed by the liquid. Since liquid is not compressible, the pressure can be rapidly reduced by discharging a very small amount, but since gas is compressible, the pressure does not immediately decrease even if a small amount is discharged,
This is because a high pressure continuously acts on the sealing portion to cause breakage.

When the sealed storage battery is used in an abnormal state, the internal pressure may temporarily increase. For example, when the battery is discharged with a large current or overcharged, gas is generated inside the battery case, and the internal pressure of the battery may increase. At this time, it is necessary to open the safety valve and discharge gas. When the battery internal pressure drops to a normal value, the safety valve is closed. When the safety valve is closed, the sealed storage battery is ready for reuse. When the safety valve is opened, a small amount of gas is discharged, and the battery performance is slightly reduced, but is restored to a state where it can be reused. Since the sealed type secondary battery can be charged and used repeatedly, it has a structure in which the safety valve can be used by self-returning even after operation.

A self-returning safety valve presses the surface of a valve body against a valve hole with a rubber-like elastic body or a spring. When the internal pressure of the battery case increases, the valve body is pushed by the pressure to open the valve. A spring or rubber-like elastic body is used to close the valve body. The rubber-like elastic body has a feature that it can be manufactured at a lower cost than a spring. Also, the operation does not become unstable due to rust like a spring.

A safety valve in which a valve body is brought into close contact with a valve hole by the elasticity of a rubber-like elastic body is described in, for example, Japanese Utility Model Laid-Open No. 7-18351. The safety valve described in this publication is built in a sealing plate 1 of a battery case as shown in FIG. The safety valve 2 has a rubber-like elastic body valve 4 built in an electrode cap 1 </ b> B of the sealing plate 1. The valve body 4 is compressed and sandwiched between the main body plate portion 1A of the sealing plate 1 and the electrode cap 1B, and the valve hole 1 opened in the main body plate portion 1A is provided.
a is elastically pressed into contact with the upper surface of a. Safety valve 2 of this structure
Opens the valve 4 by pushing up the valve 4 with the internal pressure of the battery acting on the valve 4 via the valve hole 1a. When the pressure acting on the valve hole 1a is low, the valve body 4 is in a closed state in which the valve body 4 is in close contact with the upper surface of the valve hole 1a with a rubber-like elastic body. When the pressure of the valve hole 1a becomes higher than the set pressure, the internal pressure acting on the valve hole 1a becomes stronger than the force of the rubber-like elastic body pressing the valve body 4 against the valve hole 1a.
The valve element 4 opens apart from the valve hole 1a. Therefore, the safety valve 2 can be opened and closed by the internal pressure of the battery case.

FIG. 2 shows a conventional safety valve which cannot be reused once it is opened. In the safety valve 2 of this figure, a thin plate 9 is sandwiched between a main body plate portion 1A and an electrode cap 1B, which constitute a sealing plate 1. The thin plate 9 is deformed by the internal pressure of the battery case 5. The thin plate 9 is greatly deformed as the internal pressure of the battery case 5 increases. The greatly deformed thin plate 9 is cut by a cutting blade 10 provided on the inner surface of the electrode cap 1B. In the safety valve 2 having this structure, when the internal pressure of the battery case 5 becomes abnormally high, the thin plate 9 is broken by the cutting blade 10, and the gas in the battery case 5 is released to the outside.

[0007]

As long as the safety valve 2 shown in FIGS. 1 and 2 operates reliably, the battery case 5 will not be damaged even if the battery internal pressure rises abnormally. However, the safety valve 2 shown in FIG.
Since the gas is discharged from the discharge port 3 of the electrode cap 1B to the outside, if the discharge port 3 is clogged, the gas cannot be discharged smoothly. When the sealed storage battery is used in an abnormal state and the internal pressure is increased, the inside of the battery may be overheated and a hot melt such as an organic polymer substance contained in the battery may be ejected. When this hot melt passes through the outlet 3 of the electrode cap 1B from the valve hole 1a of the sealing plate 1, it is cooled and clogged in the outlet 3 of the electrode cap 1B, so that the gas discharging ability may be reduced. is there.

The safety valve 2 shown in FIG. 2 is provided with a ring-shaped thin portion 15 on the inner surface of the electrode cap 1B in order to prevent this adverse effect. The thin portion 15 damages the electrode cap 1B when the discharge port 3 is clogged and the internal pressure of the electrode cap 1B increases. When the thin portion 15 is broken,
Since the electrode cap 1B is largely opened, the gas that has passed through the valve hole 1a can be quickly discharged.

However, the safety valve 2 having the structure shown in FIG.
It is extremely difficult to adjust the pressure at which the thin portion 15 is broken. This is because the rupture pressure varies greatly depending on the thickness of the thin portion 15. If the thin portion 15 is too thin, this portion is easily damaged, and the strength of the electrode cap 1B is significantly reduced. In order to avoid this evil,
When the thickness 5 is increased, the discharge port 3 of the electrode cap 1B is clogged, and even if the internal pressure becomes abnormally high, the thin portion 15 is not broken, and the gas cannot be discharged smoothly.

[0010] It is important for the safety valve to quickly discharge gas to prevent damage to the battery case even when used in an extremely severe environment in which a large amount of gas is generated in the battery case. The discharge port may be clogged with a hot melt or the like, and the battery case may be damaged even though the safety valve is open.
Even if the safety valve opens, the amount of gas generated in the battery
When the gas discharge capacity of the opened safety valve is exceeded, the internal pressure of the battery gradually increases, and the battery case may be damaged. Therefore, when the internal pressure of the battery becomes abnormally high, it is important for the safety valve to be able to smoothly discharge the gas inside by preventing the discharge port from being clogged with a hot melt or the like.

The present invention has been developed with the object of realizing this fact. An important object of the present invention is to eliminate clogging of a safety valve which has been opened due to a hot melt or the like and to expedite gas supply. It is an object of the present invention to provide a sealed storage battery provided with a safety valve that can be used safely and safely.

[0012]

In the sealed storage battery of the present invention, a safety valve 2 is built in a sealing plate 1. Safety valve 2
Opens when the internal pressure of the battery case 5 becomes higher than the set pressure, and discharges the gas in the battery case 5. The sealing plate 1 incorporating the safety valve 2 includes a main body plate portion 1A for closing an opening of the outer can 7, and an electrode cap 1B fixed to an upper surface of the main body plate portion 1A. A valve body 4 is provided between the electrode cap 1B and the main body plate 1A. The valve body 4 is disposed at a position to close the valve hole 1a opened in the main body plate portion 1A. This valve body 4
Closes the valve hole 1a when the internal pressure of the battery is lower than the set pressure, and opens the valve hole 1a when the internal pressure of the battery becomes higher than the set pressure.

Further, the electrode cap 1B has a discharge port 3 for discharging gas from the electrode cap 1B.
B is provided. Also, the electrode cap 1B
Has passed through the valve hole 1a in order to break the electrode cap 1B when the discharge port 3 provided in the electrode cap 1B is closed with the hot melt and the internal pressure of the electrode cap 1B becomes abnormally high. A thin line portion 11 which is broken by a gas having an abnormal pressure is provided.

Furthermore, in the sealed storage battery of the present invention, the outlet 3 is provided in the electrode cap 1B in connection with the thin line portion 11. When the safety valve 2 opens, the gas in the battery case 5 flows into the electrode cap 1B from the valve hole 1a,
Moreover, when the gas cannot be quickly discharged from the discharge port 3, the thin line portion 11 is broken. Since the outlet 3 is opened by being connected to the thin line portion 11, the electrode cap 1B of the sealed storage battery of the present invention breaks the electrode cap 1B by separating the outlet 3 from the thin line portion 11.

Further, in the sealed storage battery according to a second aspect of the present invention, the electrode cap 1B is provided with a cylindrical peripheral wall portion 14 which rises perpendicularly to the main body plate portion 1A. The thin wall portion 11 and the discharge port 3 are connected to each other and provided in a circumferential shape on the peripheral wall portion 14. That is, the outlet 3 and the thin line portion 11 are provided on the peripheral wall portion 14 in a circumferential shape so that the adjacent outlets 3 are connected by the thin line portion 11.

In the sealed storage battery according to a third aspect of the present invention, the valve body 4 incorporated in the electrode cap 1B is made of a rubber-like elastic body. The rubber-like elastic valve body 4 is pressed by the electrode cap 1B, and is elastically pressed against the upper surface of the valve hole 1a to be pressed into the valve hole 1a.
a is closed.

Further, in the sealed storage battery according to a fourth aspect of the present invention, the valve element 4 is constituted by a thin plate 9. In order to break the thin plate 9, a cutting blade 10 is provided on the inner surface of the electrode cap 1B. The cutting blade 10 contacts the deformable thin plate 9 and breaks it. In the safety valve 2, when the internal pressure of the battery case 5 becomes abnormally high, the thin plate 9 is deformed and broken by the cutting blade 10, the valve hole 1a is opened, and the gas in the battery case 5 is discharged.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below illustrate a sealed storage battery for embodying the technical idea of the present invention, and the present invention does not specify the sealed storage battery as follows.

Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “ In the column of “means”.
However, the members described in the claims are not limited to the members of the embodiments.

The sealed storage battery shown in FIG. 3 is a cylindrical nickel-cadmium battery, in which an electrode body 6 is placed in a battery case 5 and filled with an electrolyte (not shown). The battery case 5 hermetically closes the opening of the outer can 7 with the sealing plate 1. The outer can 7 is manufactured by pressing a metal plate such as an iron plate into a cylindrical shape with a bottom, that is, a bottomed cylindrical shape. The outer can 7 made of an iron plate has its surface plated with nickel or the like after the press working or before the press working.

Although the sealed storage battery shown in the figure is a nickel-cadmium battery, the present invention does not specify a sealed storage battery as a nickel-cadmium battery. The sealed storage battery may be, for example, a nickel-metal hydride battery or a lithium ion secondary battery. In a sealed storage battery that is a nickel-cadmium battery, the negative electrode of the electrode body 6 is connected to the outer can 7,
The positive electrode is electrically connected to the sealing plate 1.

The outer can 7 is formed in a bottomed cylindrical shape or a fixed-angle cylindrical shape. The outer can 7 is airtightly closed by fixing the sealing plate 1 by caulking the opening. Sealing plate 1
Sandwiches the insulating packing 8 between the outer cans 7. The insulating packing 8 electrically insulates the outer can 7 from the sealing plate 1 and prevents gas leakage therebetween.

FIG. 4 is a sectional view of a sealing plate of the sealed storage battery,
FIG. 5 is a sectional view showing a state in which the safety valve is opened and the electrode cap is broken. The sealing plate 1 shown in these figures includes a safety valve 2 that opens when the internal pressure of the battery case becomes higher than a set pressure.

The safety valve 2 is built in the sealing plate 1. The sealing plate 1 in which the safety valve 2 is incorporated has an electrode cap 1B fixed to the upper surface of the main body plate portion 1A by spot welding. The electrode cap 1B has a central portion protruding upward, and the main body plate portion 1A has a central portion protruding downward.
The valve body 4 of the safety valve 2 is built in between the valve body 1A and the main body plate 1A. The body plate portion 1A has a valve hole 1a opened at the center. On the outer peripheral edge of the valve hole 1a, a ridge 12 for sealing the valve body 4 in an airtight manner is provided. In the valve hole 1 a having the ridge 12, the leading edge of the ridge 12 is linearly adhered to the lower surface of the valve element 4. Therefore, there is a feature that gas leakage from the closed safety valve 2 can be effectively prevented.

The valve body 4 is a rubber-like elastic body. The hardness of the valve body 4 which is a rubber-like elastic body is adjusted to an optimum value in consideration of the valve opening pressure of the safety valve 2 and the size of the valve hole 1a. When a flexible rubber-like elastic body is used for the valve body 4, the pressure at which the safety valve 2 opens is reduced. Conversely, when a rubbery elastic body having high hardness is used for the valve body 4, the pressure at which the safety valve 2 opens is increased. Further, even if the hardness of the valve element 4 is the same, when the inner diameter of the valve hole 1a increases, the pressure at which the safety valve 2 opens increases. This is because the force with which the valve element 4 is pressed by the internal pressure of the valve hole 1a is proportional to the product of the internal pressure and the opening area of the valve hole 1a.

The valve opening pressure of the safety valve 2 at which the valve element 4 is separated from the valve hole 1a is set to, for example, 1 to 2 MPa. The valve opening pressure of the safety valve 2 is set to a pressure sufficiently lower than the pressure at which the battery case 5 bursts. The size of the valve hole 1a depends on the size of the battery, but is, for example, about 3.5 mm for a C-cell.

The electrode cap 1B has a portion protruding upward, that is, a cylindrical peripheral wall portion 14 standing upright with respect to the main body plate portion 1A. The peripheral wall portion 14 has four discharge ports 3 opened. Each of the four discharge ports 3 is formed in an elongated rectangular shape extending in a circumferential direction on a cylindrical peripheral wall portion 14. Further, the adjacent outlets 3 are connected so that the outlets 3 are connected, and a thin line portion 11 is provided on the inner surface of the peripheral wall portion 14 of the electrode cap 1B. As shown in the cross-sectional view of FIG. 6, the thin line portion 11 is provided with a groove 13 provided inside the electrode cap 1B. The thin line portion 11 is provided on the inner surface of the peripheral wall portion 14 of the electrode cap 1B so as to extend in the circumferential direction. When the discharge port 3 of the electrode cap 1B is clogged, the thin line portion 11 is broken and opens the inside of the electrode cap 1B. Therefore, the thin line portion 11 is set at a pressure sufficiently lower than the pressure at which the battery case bursts.

When the pressure in the battery case of the battery is lower than the set pressure, the safety valve 2 having this structure is kept in a closed state as shown in FIG. The valve body 4 is the main body plate 1
This is because the valve hole 1a is closed by being pressed against A. When the internal pressure of the battery rises, the gas pressure acting on the valve hole 1a pushes up the valve body 4 to open the valve hole 1a and open the valve. In this state, gas in the battery passes through the valve hole 1a of the main body plate portion 1A and the outlet 3 of the electrode cap 1B and is discharged out of the battery.

When the valve body 4 is opened, a hot melt or the like is injected into the electrode cap 1B from the valve hole 1a and clogs the discharge port 3, and the internal pressure of the electrode cap 1B becomes abnormally high. When the internal pressure of the electrode cap 1B becomes abnormally high,
As shown in FIG. 5, the thin line portion 11 of the electrode cap 1B is broken by the internal pressure. In this state, the electrode cap 1B is opened widely, and the gas passing through the valve hole 1a is quickly discharged to the outside. Therefore, the internal pressure of the battery case is reduced.

In the sealed storage battery having the above structure, the valve element 4 of the safety valve 2 is made of a rubber-like elastic body. However, the valve element of the safety valve does not necessarily need to be made of rubber-like elastic material,
For example, although not shown, a structure in which the plate-shaped valve body is pressed against the upper surface of the valve hole by a spring built in the electrode cap may be employed. As described above, the safety valve that closes the valve hole with the rubber-like elastic body or the spring is closed when the internal pressure of the battery case decreases. Therefore, when the internal pressure of the battery case decreases normally, the battery case can be reused as a normal battery.

FIG. 7 shows a sealing plate 1 incorporating a safety valve 2 which does not close once the valve is opened. In the sealing plate 1 in this figure, a thin plate 9 is sandwiched between a main body plate portion 1A and an electrode cap 1B. The thin plate 9 closes the valve hole 1a without being damaged. On the inner surface of the electrode cap 1B, a cutting blade 10 for breaking the thin plate 9 is provided to protrude downward. Further, an outlet 3 and a thin line portion 11 are provided on the inner surface of the electrode cap 1B, similarly to the above-described safety valve 2 shown in FIG.

When the pressure in the battery case of the battery is lower than the set pressure, the safety valve 2 of this structure is kept closed as shown in FIG. This is because the valve element 4 closes the valve hole 1a. When the internal pressure of the battery rises, the gas pressure acting on the valve hole 1a pushes up the valve body 4, and the valve body 4
Is broken by contact with In this state, the valve hole 1a is opened and the valve is opened. In this state, gas in the battery passes through the valve hole 1a of the main body plate portion 1A and the outlet 3 of the electrode cap 1B and is discharged out of the battery.

When the valve body 4 is opened, a hot melt or the like is injected into the electrode cap 1B from the valve hole 1a and clogs the discharge port 3, and the internal pressure of the electrode cap 1B becomes abnormally high. When the internal pressure of the electrode cap 1B becomes abnormally high,
Similar to the electrode cap 1B shown in FIG. 5, the thin line portion 11 of the electrode cap 1B is broken by the internal pressure. In this state, the electrode cap 1B is opened widely, and the gas passing through the valve hole 1a is quickly discharged to the outside. Therefore, the internal pressure of the battery case is reduced.

[0034]

The sealed storage battery provided with the safety valve according to the present invention has a feature that the safety valve is reliably opened to minimize clogging caused by hot melt and the like, and that gas can be quickly discharged and used safely. There is. That is, the sealed storage battery of the present invention is configured such that the electrode cap of the sealing plate is provided with a thin line portion which is broken by abnormal gas pressure passing through the valve hole, and discharges gas flowing into the electrode cap through the valve hole. This is because the discharge port is opened while the discharge port is connected to the thin line portion. The electrode cap connecting the thin line portion with the discharge port can shorten the entire length of the thin line portion and open the electrode cap largely at the thin line portion to be destroyed. If the length of the thin line portion is long, it is extremely difficult to accurately control the pressure at which the thin line portion breaks. However, in the sealed storage battery of the present invention, since the thin line portion of the electrode cap is connected at the outlet, the total length of the thin line portion is short, and the battery can be reliably broken by an abnormal internal pressure of the electrode cap. In particular, in the sealed storage battery of the present invention, the entire length of the thin line portion is shortened at the outlet for discharging the gas in the electrode cap. In the sealed storage battery having this structure, the outlet is used for both the function of discharging gas from the electrode cap and the function of reliably destroying the electrode cap. For this reason, the sealed storage battery of the present invention realizes a feature that the gas passing through the valve hole can be reliably discharged from the electrode cap with a simple structure.

In particular, in the sealed storage battery of the present invention, since the electrode cap is reliably broken to discharge gas,
Even if the discharge port is closed by a hot melt or the like, there is a feature that gas can be reliably released from the electrode cap and used extremely safely.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a safety valve built into a sealing plate of a conventional sealed storage battery.

FIG. 2 is a cross-sectional view of a safety valve incorporated in a sealing plate of another conventional sealed storage battery.

FIG. 3 is a partially sectional side view of a sealed storage battery provided with a safety valve according to an embodiment of the present invention.

FIG. 4 is a partial cross-sectional side view of a sealing plate of the sealed storage battery shown in FIG. 3;

5 is a partial cross-sectional side view showing a state in which the safety valve of the sealing plate shown in FIG. 4 is opened and the electrode cap is broken.

FIG. 6 is an enlarged sectional view showing a thin line portion provided on the electrode cap of the sealing plate shown in FIG. 4;

FIG. 7 is a cross-sectional view of a sealing plate of a sealed storage battery according to another embodiment of the present invention.

[Explanation of symbols]

1. Sealing plate 1A: Main body plate 1
B ... Electrode cap 1a ... Valve hole 2 ... Safety valve 3 ... Discharge port 4 ... Valve 5 ... Battery case 6 ... Electrode body 7 ... Outer can 8 ... Insulating packing 9 ... Thin plate 10 ... Cutting blade 11 ... Thin line part 12 ... Convex Article 13: Groove 14: Peripheral wall 15: Thin part

Claims (4)

[Claims] 1. A sealing plate (1) containing a safety valve (2) that opens when the internal pressure of a battery case (5) becomes higher than a set pressure, and a sealing plate (1) containing a safety valve (2) is provided. A body plate (1A) for closing the opening of the outer can (7), and this body plate
It consists of an electrode cap (1B) fixed on the upper surface of (1A), and between the electrode cap (1B) of the sealing plate (1) and the main body plate (1A), the main body plate (1A). Open valve hole (1
A valve body (4) that closes a) is built in, and the valve body (4) closes the valve hole (1a) when the internal pressure of the battery is lower than the set pressure, and the internal pressure of the battery becomes higher than the set pressure. Higher, the valve hole (1a)
The electrode cap (1B) further includes a thin line portion (11) that is broken by an abnormal pressure gas passing through the valve hole (1a), and a valve hole.
(1a) In a sealed storage battery equipped with a safety valve provided with a discharge port (3) for discharging gas flowing into the electrode cap (1B) through the electrode cap (1B), the electrode cap (1B) has a thin line portion ( An outlet (3) is provided in connection with (11), and the gas of abnormal pressure that has passed through the valve hole (1a) is separated from the outlet (3) by the thin line portion (11). A sealed storage battery provided with a safety valve, which is configured to break (1B). 2. An electrode cap (1B) is attached to a main body plate (1).
A) has a cylindrical peripheral wall (14) rising vertically with respect to the thin wall part (11) and the discharge port (3).
The sealed storage battery provided with the safety valve according to claim 1, which is connected to each other and provided in a circumferential shape. 3. The hermetic seal provided with the safety valve according to claim 1, wherein the valve body (4) is a rubber-like elastic body, and the valve body (4) presses against the upper surface of the valve hole (1a) to close the valve hole (1a). Type storage battery. 4. A cutting blade, wherein the valve body (4) is a thin plate (9), and the thin plate (9) breaks when deformed by gas passing through the valve hole (1a).
The sealed storage battery provided with the safety valve according to claim 1, wherein (10) is provided on an inner surface of the electrode cap (1B).