JPH06196139A - Explosion-proof type sealed battery - Google Patents

Abstract

PURPOSE:To open a safety valve after current is shut off. CONSTITUTION:The safety valve of a sealed battery is provided with a conductive valve body 2 which is deformed when the pressure in the battery is increased, and an elastic thin plate 2A, which is broken to open the valve when a predetermined level of pressure is attained. The elastic thin plate 2A is pressed and broken by the gas in the battery that passes the valve body 2. The valve body 2 is connected to an intermediate connection body under a condition that the opening part of an outer packaging can 10 is closed. When the inner pressure of the battery is increased, the valve body 2 is separated from the intermediate connection body, and a part of the valve body 2 is broken, and the elastic thin plate 2A is pressed and broken by the gas in the battery that passes the broken opening part, The gas does not pass the valve body until the valve body is broken. The elastic thin plate is broken by the gas in an electrode, which penetrates the broken valve body. A safety valve is thus opened after current is shut off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an explosion-proof sealed battery, and more particularly to an explosion-proof sealed battery in which a safety valve is opened after the current is cut off when the internal pressure of the battery rises.

[0002]

2. Description of the Related Art A sealed battery may have an abnormal increase in internal pressure depending on use conditions. For example, the internal pressure of a lithium ion secondary battery rises abnormally when overcharged. Also,
There is a property that the internal pressure rises even when a short circuit occurs and an excessive current flows. When the internal pressure rises abnormally and the outer can of the battery ruptures, the electrical equipment that houses the battery may be damaged. Further, if a corrosive gas or an electrolyte leaks from the ruptured outer can, this also has a harmful effect of corroding electrical equipment. In order to avoid this drawback, the explosion-proof sealed battery is provided with a mechanism for preventing an abnormal rise in internal pressure. An abnormal rise in internal pressure when overcharged can be prevented by shutting off the current inside the battery. This is because when the electric current is cut off, a chemical reaction does not occur inside the battery.

Explosion-proof sealed batteries that realize such a thing are disclosed in JP-A-2-112151 and JP-A-2-2.
No. 88063. The sealed batteries described in these publications are equipped with the sealing body 1 having the structure shown in FIGS. 1 to 3. The sealing body 1 includes a valve body 2 that connects a lead wire 4 and a stopper 3 provided between the lead wire 4 and the valve body 2. The lead wire 4 and the valve body 2 are
The valve bodies 2 are connected with a strength that allows them to separate when deformed by an abnormal pressure. The valve body 2 is electrically connected to the cap 6, and the cap 6 is connected to the lead wire 4 via the valve body 2. The stopper 3 is provided to forcibly separate the valve body 2 from the lead wire 4 when the internal pressure of the battery rises abnormally. In other words, the stopper 3 prevents the lead wire 4 from moving together with the valve body 2 when the valve body 2 is deformed by an abnormal pressure, and disconnects the connection between the valve body 2 and the lead wire 4. Is. Therefore, the stopper 3 has the through hole 5, and the gas passing through the through hole 5 presses the inner surface of the valve body 2 to deform it.

The sealed battery having this structure performs the following operation to prevent an abnormal increase in internal pressure. Normal state in which the internal pressure of the battery does not rise abnormally In this state, the valve body 2 is connected to the lead wire 4.
This is because the valve body 2 is not deformed by the internal pressure of the battery. The battery cap 6 is connected to the power generation element 7 via the valve body 2 and the lead wire 4 and is in a state capable of conducting electricity. State where internal pressure of battery rises higher than set pressure When internal pressure of battery rises, valve body 2 is pushed up by the pressure as shown in FIG. The stopper 3 prevents the lead wire 4 from rising. Therefore, the lead wire 4 is in a fixed position, only the valve body 2 is lifted, and the valve body 2 is separated from the lead wire 4. When the valve body 2 is separated from the lead wire 4, the current is cut off inside the battery. When this happens,
The electric current stops flowing to the battery, and the chemical reaction inside the battery stops. Therefore, the rise in internal pressure is limited. When the internal pressure rises even when the current is cut off When the internal pressure of the battery further rises, as shown in FIG. 3, the deformation amount of the valve body 2 further increases and a part of the valve body 2 is destroyed. The destroyed valve body 2 exhausts the gas in the battery. The gas that has passed through the valve body 2 is exhausted to the outside of the battery through the gas vent hole 8 of the cap 6.

[0005]

In the explosion-proof sealed battery having the above structure, when the internal pressure rises, the valve body is broken and the gas inside the battery is exhausted. It is difficult to accurately control the breaking pressure in the structure in which the part is broken by the internal pressure. A part of the valve body is thinned by providing a V groove so that the valve body is easily broken by the internal pressure. The thickness of the valve body is adjusted by the depth of the V groove, and the breaking pressure is adjusted by the thickness of the valve body. However, in the structure in which the V groove is provided to control the remaining film pressure of the valve body, a slight change in the depth of the V groove greatly changes the film pressure of the valve body. This is because the film thickness is considerably thin. With this structure, an extremely high-precision processing technique is required in order to uniformly adjust the film thickness at the broken portion of the valve body. If the processing accuracy is lowered, the film thickness at the fractured portion varies, and the fracture pressure fluctuates. Therefore, with this structure, the explosion-proof sealed battery whose valve body is broken has a drawback that it is difficult to mass-produce inexpensively and to control the breaking pressure uniformly.

As shown in FIG. 4, this drawback can be eliminated by stacking the flexible thin plate 2A on the valve body 2 and closely contacting the flexible thin plate 2A. The flexible thin plate 2A is designed to break when a constant pressure is applied. The explosion-proof sealed battery of this structure cuts off the current by disconnecting the valve body 2,
Break A to prevent the internal pressure from rising. Flexible thin plate 2A
Is designed to have a material and a film thickness that can be broken at a constant pressure, so that it has an advantage that the breaking pressure can be accurate.

However, in the battery having this structure, the flexible thin plate may be broken before the current is cut off. This is because it is difficult to accurately control the strength of welding the valve body to the intermediate connecting body. If the connection strength between the valve body and the intermediate connection body is too strong, even if the internal pressure of the battery rises considerably,
The valve body does not separate from the intermediate connector. Therefore, the flexible thin plate may be broken and the safety valve may be opened before the valve body is separated from the intermediate connector. This condition is by no means desirable. This is because when the flexible thin plate breaks, the internal pressure of the battery drops, so that the valve body cannot be separated from the intermediate connector after that, and the battery current cannot be cut off. The internal pressure of the battery that separates the valve body from the intermediate connector needs to be lower than the pressure at which the flexible thin plate breaks. This is because when the internal pressure of the battery rises even if the current is cut off, the flexible thin plate is broken to prevent the internal pressure from rising.

In order to connect the valve body to the intermediate connecting body so that the valve body is disconnected when a constant pressure is applied, extremely high precision processing technology is required. This is because the connection strength is adjusted by the strength with which the valve body is welded to the intermediate connection body.
The variation in connection strength changes the operating pressure of the valve body, that is, the pressure at which the valve body is disconnected from the intermediate connection body. If the connection strength of the valve body is weak, the valve body easily comes off the intermediate connection body. Therefore, when the internal pressure of the battery is low, the current is cut off and the battery cannot be reused. On the other hand, if the connection strength is too strong, the valve body cannot be separated from the intermediate connection body even if the internal pressure of the battery rises to the set pressure, and the internal pressure of the battery is significantly increased. The connection strength between the valve body and the intermediate connection body is controlled by the strength of welding the valve body to the intermediate connection body. Be in trouble,
When a part of the valve body is melted and connected, the metal is heated to a high temperature in the welded part, the physical properties and the shape are changed, and the weld strength varies. Therefore, it is considerably difficult to make the connection strength between the valve body and the intermediate connection body uniform.

The present invention provides an explosion-proof sealed battery capable of preventing an increase in internal pressure by shutting off the current and then opening the safety valve without being affected by the connection strength between the valve body and the intermediate connection body. It was developed for the purpose.

[0010]

The sealed battery of the present invention has the following constitution in order to achieve the above-mentioned object. The sealed battery has a built-in safety valve that opens when a predetermined pressure is reached and releases the gas in the battery. The safety valve includes a conductive valve body 2 that deforms as the pressure in the battery rises, and a flexible thin plate 2A that breaks and opens at a predetermined pressure. The gas in the battery that has passed through the valve body 2 presses the flexible thin plate 2A and breaks it, so that the safety valve is opened.

The valve body 2 is connected to the intermediate connecting body connected to the power generating element 7 in a state where the opening of the outer can 10 is closed. That is, in the normal state, the valve element 2 is connected to the intermediate connector without breaking. The intermediate connector is
It is the lead wire 4 connected to the power generation element 7, or the intermediate plate 9 connected to the lead wire 4. When the internal pressure of the battery rises, the valve body 2 is separated from the intermediate connection body and a part thereof is broken. An opening is formed in the broken portion of the valve body 2. The gas in the battery passes through the broken opening to allow the flexible thin plate 2
Press A to break.

[0012]

The function of the explosion-proof sealed battery of the present invention is not such that the valve body is provided with a gas hole unlike the conventional battery. In a normal use state, the valve body is sealed without opening the gas hole. The valve body having the closed structure is broken and opened when the internal pressure of the battery rises and the valve body is separated from the intermediate connection body. Gas in the battery passes through this opening to press and break the flexible thin plate 2A.

The sealed battery of FIGS. 5-7, which illustrates a preferred embodiment of the present invention, interrupts current in the following conditions. Normal state in which the internal pressure of the battery does not rise In this state, the valve body 2 is connected to the intermediate plate 9. Therefore, the battery cap 6 is connected to the power generating element 7 via the valve body 2 and the intermediate plate 9 to be in an energized state. In this state, the valve body 2 hermetically closes the opening of the outer can 10. State in which the internal pressure of the battery is higher than the set pressure When the internal pressure of the battery is increased, the valve body 2 is pushed up by the pressure and the connection portion with the intermediate plate 9 is disconnected, as shown in FIG. The valve element 2 separated from the intermediate plate 9 is fractured at the connecting portion with the intermediate plate 9 or is fractured in the vicinity thereof. The valve body 2 separated from the intermediate plate 9 blocks the electric current. When the internal pressure rises even when the current is shut off When the internal pressure of the battery rises further, as shown in FIG. Break. The broken flexible thin plate 2A is
The gas in the battery is exhausted with the safety valve opened. That is, the gas passing through the valve body 2 is exhausted to the outside of the battery through the gas vent hole 8 of the cap 6. In this way, in the explosion-proof sealed battery, the valve body 2
When the pressure further rises after opening a part of it, the flexible thin plate 2A is broken to prevent the internal pressure from rising and the outer can 10 is prevented from bursting.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. However, the examples shown below exemplify a sealed battery for embodying the technical idea of the present invention,
The sealed battery of the present invention includes the types of components, types, materials,
The shape, structure, and arrangement are not specified below.
The sealed battery of the present invention can be modified in various ways within the scope of the claims.

Further, in this specification, for easy understanding of the claims, the numbers corresponding to the members shown in the embodiments are referred to as "claims column", "action column", and "action column". It is added to the members shown in the section of "Means for Solving the Problems". However, the members shown in the claims are
It is by no means specific to the members of the examples.

The explosion-proof sealed battery shown in FIG. 5 to FIG. 7 closes the outer can 10, the power generating element 7 made of + and − electrode plates housed in the outer can 10, and the opening of the outer can 10. And a sealing body 1 equipped with a safety valve. The outer can 10 has a cylindrical shape with a closed bottom, and the sealing body 1 is caulked and fixed to the opening at the upper end.

The sealing body 1 is caulked and fixed to the outer can 10 via an insulating packing 11 to hermetically close the outer can 10. The sealing body 1 cuts off the current when the internal pressure of the battery rises. After the electric current is cut off, the internal gas is exhausted when the internal pressure further rises.

In order to realize this, the sealing body 1 is
The cap 6, the valve body 2, and the intermediate connection body are provided. The intermediate connecting body connects the valve body 2 to the power generating element 7, and the battery shown in the figure comprises the intermediate connecting body with the intermediate plate 9 and the lead wire 4. Since the cap 6, the valve body 2, and the intermediate plate 9 are required to have electrical conductivity, they are manufactured by pressing a metal plate. In the sealing body 1 having this structure, the cap 6 serves as a + electrode. The cap 6 includes the valve body 2, the intermediate plate 9, and the lead wire 4.
It is connected to the + electrode plate which is the power generation element 7 via. The cap 6, the valve body 2, and the intermediate plate 9 are cut into a disc shape. The peripheral edge of the intermediate plate 9, which is a metal plate, is bent upward, and is crimped to sandwich the valve body 2 and the cap 6 to connect the three metal plates. Although the cap 6 and the valve body 2 are in direct contact with each other, the insulating packing 12 is sandwiched between the valve body 2 and the intermediate plate 9.

The cap 6 is pressed into a convex shape at the center,
The gas vent hole 8 is opened. The valve element 2 is a rupture disk that reverses the convex portion upward when pressure is applied, as shown in FIG. The valve body 2 of the rupture disc has a curved portion projecting downward in the central portion. The lower end of the curved portion is spot-welded or ultrasonic-welded and spot-welded to the upper surface of the intermediate plate 9. When the internal pressure of the battery increases, the curved portion of the valve body 2 that is a rupture disk is inverted and deformed upward as shown in FIG. When the bending portion is reversed, the valve body 2 is separated from the intermediate plate 9.

Further, in the state shown in FIG. 5, the valve body 2 seals the upper end opening of the outer can 10 so that the gas in the battery does not pass upward. That is, in the valve body 2, the gas hole is not opened in the state of being connected to the intermediate plate 9, and the upper portion of the intermediate plate 9 is hermetically sealed to close the safety valve.
The valve body 2 is designed to have such strength that the valve body 2 is deformed by the internal pressure of the battery and is partially cut to open in a state of being separated from the intermediate plate 9, as shown in FIG. 6.

FIG. 10 shows a state in which the valve element 2 connected to the intermediate plate 9 in the state shown in FIG. 9 is separated from the intermediate plate 9. The valve body 2 is broken, leaving a portion welded to the intermediate plate 9. The valve body 2 is provided with a ring-shaped groove along the outer periphery of the welded portion. The groove has an effect of identifying a breakage position of the valve body 2 separated from the intermediate plate 9 and further facilitating the breakage of the valve body 2.

The valve body 2 welded to the intermediate plate 9 in a normal state.
Is shown in FIG. The valve body 2 shown in this figure is the valve body 2
The thickness d and the welding area B1 with the intermediate plate 9 determine the welding strength. If the valve body 2 is thick and the welding area B1 is large,
The strength with which the valve body 2 is welded to the intermediate plate 9 increases. Therefore, the pressure at which the valve body 2 is separated from the intermediate plate 9 becomes high. With this structure, the area B1 where the valve body 2 is welded to the intermediate plate 9
It is difficult to make the area small and to adjust the area accurately. This is because the radius of curvature of the curved portion of the valve element 2 is large and the intermediate plate 9 is in contact with the tangential direction.

FIG. 12 shows a specific example in which the welding area between the valve body 2 and the intermediate plate 9 can be reduced. The intermediate plate 9 shown in this figure has a conical minimal projection 16 at the portion welded to the valve body 2.
Is provided. The minimum protrusion 16 has a radius of curvature (θ
By adjusting 1), the welding area of the valve body 2 welded to the tip can be adjusted. By reducing the radius of curvature (θ2) as shown in FIG. 13, the welding area between the valve body 2 and the intermediate plate 9 can be reduced. On the contrary, if the radius of curvature of the tip of the minimal protrusion 16 is increased, the welding area can be increased. In order to provide the minimal protrusions 16 on the intermediate plate 9, as shown in FIG.
Is pushed up by the protrusion 22 of the press die. When the intermediate plate 9 is pressed by the tip, the protrusion 22 of the press die can be sandwiched between the protrusion 22 and the female die 23 and press-formed to have an accurate radius of curvature, as shown in FIG.

When a thin metal plate is used for the valve body 2, as shown in FIG. 15, the intermediate plate 9 can be concavely formed along the curved portion of the valve body 2 to increase the welding area. . In this case, welding is performed with the curved portion of the valve body 2 fitted in the recess of the intermediate plate 9. With this structure, the area of the press-formed concave portion of the intermediate plate 9 can be adjusted to specify the welding area between the valve body 2 and the intermediate plate 9.

Further, as shown in FIG. 16, a minimum protrusion 19 is provided at the lower end of the curved portion of the valve body 2 to allow the intermediate plate 9 and the valve body 2 to be in contact with each other.
It is also possible to reduce the welded area with. In the valve body 2 having this shape, the welding area between the valve body 2 and the intermediate plate 9 can be specified by adjusting the radius of curvature of the tip of the minimal protrusion 19. Minimal projection 19
If the radius of curvature of is reduced, the welding area between the valve body 2 and the intermediate plate 9 is reduced.

Furthermore, as shown in FIG. 17, the valve body 2
It is also possible to reduce the welding area between the valve body 2 and the intermediate plate 9 by providing the minimal protrusions 16 and 19 on both the curved portion and the intermediate plate 9.

As described above, in the safety valve in which the valve body and the intermediate plate 9 are provided with the minimal protrusions and the welding area between the valve body and the intermediate plate 9 is adjusted to be small, the valve body is formed by the minimal protrusions. It is possible to accurately adjust the pressure in the battery to be separated from the valve body, and to make the valve body thicker without increasing the pressure in the battery to disconnect the valve body from the intermediate plate 9 by reducing the curvature radius of the minimal protrusion. .

The valve body having the above structure has a flexible thin plate which is ruptured at a constant pressure laminated on the upper surface. The flexible sheet is
After the valve body is separated from the intermediate plate and broken, and when the internal pressure of the battery further rises, the valve body is broken and the safety valve is opened. The flexible thin plate is airtightly adhered to the upper surface of the valve body while airtightly closing the upper surface of the valve body. When a part of the valve body is broken, the flexible thin plate is pressed by the gas passing through the valve body. The flexible thin plate pressed by the gas breaks at a constant pressure. When the valve body and the flexible thin plate are broken, the gas in the battery passes through the valve body and the flexible thin plate and is exhausted to the outside of the battery. That is, the safety valve of the sealing body is opened. As the flexible thin plate, one that breaks when the pressure exceeds a set value can be used. Furthermore, the flexible lamellae are preferably designed such that the breaking strength decreases with increasing temperature. This is for reliably breaking the flexible thin plate when the battery temperature rises due to overcharge.

As the flexible thin plate 2A having this characteristic, as shown in FIG. 5, a laminated plate in which a plastic film 2b is laminated on a metal thin film 2a is used. For the metal thin film 2a, a corrosion-resistant metal foil such as titanium, stainless steel, or aluminum can be used. Aluminum is most suitable for these metal thin films 2a. This is because it is inexpensive, easy to make into a thin film, and has an optimum strength. When aluminum is used for the metal thin film 2a, the thickness of the metal thin film 2a is usually 10 μm to 30 μm.
It is designed to be 0 μm, preferably 15 μm to 50 μm. For the plastic film 2b, a thermoplastic synthetic resin such as polyethylene or polypropylene can be used. The thickness of the plastic film 2b is usually designed to be in the range of 10 μm to 500 μm, preferably 20 μm to 100 μm. The flexible thin plate 2A having this structure can be manufactured by coating the surface of the metal thin film 2a with plastic. Alternatively, the metal thin film 2a and the plastic film 2b can be manufactured by adhering them with an adhesive. The simplest flexible thin plate 2A is a two-layer laminated plate in which a plastic film 2b is laminated on one surface of a metal thin film 2a. However, a plastic film 2b laminated on both sides of the metal thin film 2a, or a plastic film 2b
It is also possible to use a laminate in which the metal thin films 2a are laminated on both surfaces of the above, or a laminate plate in which a plurality of metal thin films 2a and plastic films 2b are laminated.

The flexible thin plate 2A of the battery shown in FIG. 5 is airtightly welded to the upper surface of the valve body 2 with the plastic film 2b on the lower surface. The flexible thin plate 2A is a polyswitch (hereinafter referred to as PTC) sandwiched between the cap 6 and the valve body 2.
It is cut into a disk shape smaller than 20. A ring-shaped PTC 20 is sandwiched between the cap 6 and the valve body 2,
A flexible thin plate 2A is arranged inside C20. PTC
Reference numeral 20 electrically connects the valve body 2 and the cap 6. P
The resistance of TC20 increases rapidly when the temperature rises,
Reduce the battery current.

However, although not shown, a flexible thin plate may be sandwiched between the cap and the valve body. However, in this case, a conductive metal foil is used for the flexible thin plate, or the cap and the valve body are spot-welded through the flexible thin plate or electrically connected at the outer periphery.

The intermediate plate 9 penetrates through the intermediate plate 9 and the gas permeation hole 1
4 is open. The gas transmission holes 14 allow the gas to pass through the intermediate plate 9.
The valve body 2 is deformed by the internal pressure of the battery. The lead wire 4 is connected to the lower surface of the intermediate plate 9. Lead wire 4
Connects the intermediate plate 9 to the power generating element 7. That is, FIG.
The sealing body 1 shown in FIG. 1 includes a cap 6, a valve body 2, and an intermediate plate 9
And the lead wire 4 are connected to the power generation element 7.

In the sealing body 1 shown in FIGS. 5 to 8, the intermediate plate 9 is caulked to fix the valve body 2 and the cap 6 to each other. In the sealing body 1 shown in FIG. 18, an insulating plate 21 is sandwiched between the valve body 2 and the intermediate plate 9. The insulating plate 21 is provided with a ring groove at the center of its upper surface, and the valve body 2 is fitted therein. This structure has a feature that the valve body 2 can be accurately positioned. Further, the insulating plate 21 is made of heat-resistant plastic. The sealing body 1 using the insulating plate 21 made of heat-resistant plastic has a feature that when the valve body 2 is welded to the intermediate plate 9, it can be prevented from being melted by heat during welding.

Further, the sealing body 1 shown in FIG.
The central part of the is protruded downward in a columnar shape, and a metal foil is airtightly welded to the lower end to seal it. Aluminum foil can be used as the metal foil. The metal foil is welded to the upper surface of the minimal protrusion 16 of the intermediate plate 9. In the valve body 2 having this structure, the diameter (D) of the columnar portion and the radius of curvature of the upper end of the minimal protrusion 16 can be adjusted to adjust the pressure for interrupting the current. When the diameter (D) of the columnar portion is increased and the radius of curvature of the minimal projection 16 is reduced, the pressure for separating the metal foil from the intermediate plate 9 becomes low. This is because when the diameter of the columnar portion is increased, the pressure receiving area is increased and the metal foil is easily deformed, and by reducing the radius of curvature of the minimal protrusion 16, the strength of welding the metal foil to the intermediate plate 9 is weakened. Because it will be.

Further, the pressure at which the valve body 2 is separated from the intermediate plate 9 can be adjusted by a ring 17 provided between the valve body 2 and the cap 6, as shown by the broken line in FIG.
The ring 17 elastically presses the upper surface of the valve body 2 to press the valve body 2 against the intermediate plate 9. When the inner diameter of the ring 17 is reduced and the pressing force of the valve body 2 is increased, the valve body 2 is less likely to be deformed, the pressure of the battery that separates the valve body 2 from the intermediate plate 9 is increased, and the set pressure for cutting off the current is increased. Get higher For the ring 17, a cylinder or a coil spring that elastically deforms is used.

The sealing body 1 shown in FIGS. 5 to 8 having the cap 6, the valve body 2 and the intermediate plate 9 can be assembled in the following steps. The valve body 2 is set on the intermediate plate 9 whose peripheral edge is bent upward through an insulating packing. The center of the valve body 2 is welded to the intermediate plate 9. A flexible thin plate 2A is welded to the upper surface of the valve body 2. The PTC 20 is placed on the outer periphery of the valve body 2, and the cap 6 is placed on the PTC 20. The peripheral edge of the intermediate plate 9 is bent, and with the intermediate plate 9, the peripheral edges of the valve body 2, the PTC 20 and the cap 6 are caulked and fixed via the insulating packing 12.

Further, the sealing body in which the ring is interposed between the valve body and the cap is such that the insulating packing, the valve body, the PTC, the ring and the cap are laminated in this order on the upper surface of the intermediate plate, and the peripheral edge of the intermediate plate is After bending, the valve body, the PTC, and the cap are caulked and fixed through the insulating packing.

In the above embodiments, the intermediate plate and the lead wire are used for the intermediate connector. However, the sealed battery of the present invention,
The intermediate connecting body does not necessarily have to be the intermediate plate and the lead wire. The valve body can be directly connected to the lead wire without using the intermediate plate. In this case, when the valve body is deformed by the internal pressure of the electrode, the strength of the lead wire does not deform together with the valve body, or the lead wire is held by another member so as not to deform.

[0039]

EFFECTS OF THE INVENTION The explosion-proof sealed battery of the present invention is characterized in that it prevents the harmful effect of the safety valve opening before shutting off the current, and shuts off the current first and then opens the safety valve. Furthermore, the feature that the valve opening pressure of the safety valve can be accurately controlled can be realized. That is, the explosion-proof sealed battery of the present invention is provided with a flexible thin plate laminated on the valve body of the safety valve, and the valve body is separated from the intermediate connecting body without providing a gas hole in the valve body. This is because the part is designed to be broken. That is, in the explosion-proof sealed battery of the present invention, the valve body has a sealed structure and the flexible thin plates are laminated. The valve body has a closed structure until it is separated from the intermediate connector and a part thereof is broken. In other words, the valve body retains the sealed structure until it is disconnected from the intermediate connection body and interrupts the electric current. Therefore, the pressure of the battery does not act on the flexible thin plate until the valve body is broken. The flexible thin plate on which the internal pressure of the battery does not act does not break even if the internal pressure of the battery rises abnormally. The flexible thin plate is pressed by the internal pressure of the battery and ruptures after the valve body is separated from the intermediate connecting body and partly ruptures. The explosion-proof sealed battery of the present invention which performs this operation, when the internal pressure of the battery rises, the current is first interrupted,
After that, the safety valve is opened. The malfunction of opening the safety valve before shutting off the current is prevented.

Further, in the explosion-proof sealed battery of the present invention, since the flexible thin plate that breaks due to the internal pressure of the battery is a member separate from the valve body, the breaking pressure of the flexible thin plate can be made accurate.
In addition, since the valve opening pressure of the safety valve is not adjusted by methods such as providing a V-groove on the valve body, highly accurate machining technology is not required, and an explosion-proof sealed battery for the safety valve that can open accurately at the set pressure is inexpensive. It also realizes the feature of mass production.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a sealing body portion of a conventional explosion-proof sealed battery.

FIG. 2 is a cross-sectional view showing a state in which the internal pressure of the battery rises and the current is cut off in the sealing body portion of the sealed battery shown in FIG.

FIG. 3 is a cross-sectional view showing a sealing body portion of the sealed battery shown in FIG. 1, showing a state in which the internal pressure of the battery is further increased and a safety valve is opened.

FIG. 4 is a sectional view showing a sealing body portion of the improved sealed battery.

FIG. 5 is a cross-sectional view showing a state where the explosion-proof sealed battery of the present invention has a sealing body portion and the internal pressure of the battery is low.

6 is a cross-sectional view showing a state where the internal pressure of the battery is increased and the current is cut off, which is a sealing body portion of the sealed battery shown in FIG.

FIG. 7 is a cross-sectional view showing the sealing body portion of the sealed battery shown in FIG. 5, showing a state in which the internal pressure of the battery is further increased and the safety valve is opened.

8 is a cross-sectional view showing a sealing body portion of the sealed battery shown in FIG. 5, showing a state in which the internal pressure of the battery is further increased and the safety valve is opened.

FIG. 9 is an enlarged sectional view of a portion where the valve body is welded to an intermediate plate that is an intermediate connecting body.

FIG. 10 is a cross-sectional view showing a state in which the valve body shown in FIG. 9 is broken and separated from the intermediate plate.

FIG. 11 is an enlarged sectional view of a portion where the valve body is welded to the intermediate plate.

FIG. 12 is a cross-sectional view showing a specific example of a welded portion between a valve body and an intermediate plate.

FIG. 13 is a cross-sectional view showing a specific example of a welded portion between a valve body and an intermediate plate.

FIG. 14 is a cross-sectional view showing a pressed state in which a minimal protrusion is provided on the intermediate plate.

FIG. 15 is a cross-sectional view showing an example in which a valve body is welded to an intermediate plate having a curved portion.

FIG. 16 is a cross-sectional view showing a state in which a valve body with minimal protrusions is welded to an intermediate plate.

FIG. 17 is a cross-sectional view showing a state in which a valve body having a minimal protrusion and an intermediate plate having a minimal protrusion are welded to each other.

FIG. 18 is a cross-sectional view of a sealing body in which an intermediate plate and a valve body are sandwiched via an insulating plate.

FIG. 19 is a sectional view of a sealing body using a valve body with a metal foil.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sealing body 2 ... Valve body 2A ... Flexible thin plate 2a ... Metal thin film 2b ... Plastic film 3 ... Stopper 4 ... Lead wire 5 ... Through hole 6 ... Cap 7 ... Power generating element 8 ... Gas vent hole 9 ... Intermediate plate 10 ... Exterior can 11 ... Insulating packing 12 ... Insulating packing 13 ... Notch 14 ... Gas permeable hole 15 ... Broken connector 16 ... Minimal ridge 17 ... Ring 18 ... Gas hole 19 ... Minimal ridge 20 ... PTC 21 ... Insulation plate 22 ... Convex 23 ... Female mold

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuro Moriwaki 2-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Toru Ametsumi 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (1)

[Claims] 1. A safety valve that opens when a predetermined pressure is reached to release the gas in the battery is built in, and the safety valve has a conductive valve element (2) that is deformed as the pressure in the battery rises, and a predetermined valve. It is equipped with a flexible thin plate (2A) that breaks and opens the valve when the pressure reaches, and is configured so that the gas in the battery that has passed through the valve body (2) presses the flexible thin plate (2A) and breaks. In the explosion-proof sealed battery, the valve element is closed when the opening of the outer can (10) is closed.
It is connected to the intermediate connector connected to (7), and when the internal pressure of the battery rises, it is separated from the intermediate connector and a part is broken, and the gas inside the battery can pass through the broken opening. An explosion-proof sealed battery, characterized in that the flexible thin plate (2A) is pressed and broken.