JP3426840B2 - Pressure cutoff sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure cutoff sensor used for ensuring the safety of rechargeable rechargeable storage batteries such as secondary batteries.

[0002]

2. Description of the Related Art If a storage battery of this type is further charged, or if it is charged with a current larger than a specified current, an abnormality occurs in the storage battery and gas is generated in the storage battery. The pressure and temperature inside the storage battery rise, the storage battery expands, and the electrolyte leaks out due to cracks, which may adversely affect the device in which the storage battery is incorporated. Further, even if it has not been achieved so far, if the storage battery is continuously used in such a state, the expansion of the storage battery described above may progress, cracks or ruptures may occur, and the storage battery in which the abnormality occurs promptly. You need to stop using it.

Therefore, conventionally, safety measures have been taken for this type of storage battery, such as a type in which the storage battery is provided with a safety valve that opens when the pressure in the storage battery rises and exhausts the gas in the storage battery, and its temperature rise. For example, there is a type in which a means is provided outside the storage battery to detect and prevent current from flowing in an electric circuit connected to the storage battery.

An example of a conventional pressure cutoff sensor is shown in FIG.
1 will be described. FIG. 11 is an explanatory diagram showing a schematic configuration of a conventional pressure cutoff sensor.

As shown in FIG. 11, the conventional pressure cutoff sensor includes a metallic safety valve 43 which is deformed as the battery internal pressure rises, and a lead 45 which is connected to a central protrusion 43a provided on the safety valve 43. The reed stripper plate 46 is interposed between the safety valve 43 and the reed 45, and the insulating plate 47 that insulates the safety valve 43 and the reed stripper plate 46 from each other. The safety valve 43 is incorporated inside the storage battery 40, and at that time, the safety valve 43 is a battery case 4 having a cylindrical body with a bottom.
1 is caulked together with the battery lid 44 through the insulating gasket 42, and is fixed so as to close the open end of the battery case 41. The battery lid 44 also serves as a positive electrode terminal of the storage battery 40 and has a hole 44a formed therein, and the battery case 41 also serves as a negative electrode terminal of the storage battery 40. Insulation plate 47
Has an integrated forehead 47c, and the forehead 4
The insulating plate 47 is attached below the safety valve 43 by 7c. The lead stripper plate 46 is attached immediately below the insulating plate 47 by being fitted into a groove provided in the forehead portion 47c. The central protruding portion 43a is an insulating plate 47.
47a and 46 communicating with the lead stripper plate 46
The lead 45 is inserted into a and the lead 45 is connected to the tip thereof.

Inside the battery case 41, a winding core 48,
A power generation unit 49 configured by winding a positive electrode and a negative electrode around the winding core 48 is housed, and the negative electrode of the power generation unit 49 and the battery case 41 are connected via a lead 50. The inside of the battery case 41 is filled with an electrolytic solution (not shown).

In such a conventional pressure cutoff sensor, when the pressure inside the storage battery 40 rises due to an abnormal chemical change in the power generation element, the raised pressure acts on the safety valve 43, so that the safety valve 43 is lifted and the reed stripper is used. The plate 46 peels or breaks the conductive path connecting the central protrusion 43a and the lead 45. Then, when the pressure further increases and reaches a predetermined pressure, the thin portion of the safety valve 43 is broken, and the gas with increased pressure inside the battery case 41 is released to the outside through the hole 44a of the battery lid 44.

[0008]

However, in the above-mentioned prior art, the lead stripper plate 46 for breaking the conductive path connecting the central projection 43 of the safety valve 43 and the lead 45 is provided below the safety valve 43. Since it is disposed inside the storage battery 40, it is necessary to take care so that the arc does not fly when the conductive path is broken. As a result,
There is a problem in that the degree of freedom in design is small due to restrictions on the shape and material of the safety valve 43.

[0009]

SUMMARY OF THE INVENTION According to the present invention, an operating member fixed in a battery case in a hermetically sealed state is provided with a pressure sensitive portion that is displaced outward due to an increase in pressure inside the battery, and an external electrode is provided outside the operating member. A breaking member having a conductive path is arranged. By disposing the breaking member on the outside of the actuating member in this way, even if the arc should fly at the time of breaking the breaking member, there is no risk of ignition of the gas inside the storage battery,
It is possible to provide a highly safe pressure cutoff sensor.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the pressure cutoff sensor of the present invention, an external electrode which is one of the electrodes of a battery is fixed in a hermetically sealed state inside a battery case via an insulator, and is displaced outward by an increase in pressure inside the battery. A conductive actuation member having a pressure-sensitive portion, and a conductive path located outside the actuation member when fixed to the battery case, having one end connected to the external electrode and the other end connected to the actuation member. And a breaking member that is broken by the displacement of the pressure-sensitive portion and interrupts the conductive path.

Further, the pressure cutoff sensor of the present invention has an external electrode which is one of the electrodes of the battery, and a pressure sensitive portion which is fixed in the battery case in a sealed state and is displaced outward due to an increase in the pressure inside the battery. A member, a conductive support located outside the actuating member when fixed to the battery case, having an electric path to the inside of the battery, an insulating holding member supporting the external electrode, and the external electrode. A breaking member that has a conductive path connecting between the supports and that is broken by the displacement of the pressure-sensitive portion and interrupts the conductive path is provided. In this case, the actuating member has only to have a function of breaking the breaking member by displacement, and conductivity is not always necessary.
The degree of freedom of the shape and material of the operating member is expanded, and the structure is simple.

The conductive paths may be directly connected to the external electrodes, but a PTC may be provided between the conductive paths and the external electrodes.
By disposing the element, the current can be reduced when the temperature becomes abnormally high, and the safety against heat can be improved.

If an opening is provided in the external electrode and a pressure sensitive portion and a safety valve are provided in the actuating member, the mechanism can be simplified and the cost can be reduced by using the explosion-proof mechanism in an emergency. In particular, if the safety valve also serves as the pressure sensitive portion, it becomes easy to simultaneously manage the pressure at which the breaking member operates and the pressure at which the safety valve operates.

If the external electrode is provided with a protrusion projecting outward and the breaking member is housed in the protrusion, space can be saved and the capacity of the entire storage battery can be increased.

If a portion softened by heat treatment is formed on the actuating member and the portion surrounded by the softened portion is the pressure sensitive portion, an actuating member that is displaced in response to a change in internal pressure quickly is provided. realizable.

When the battery case is the other electrode of the battery and the conductive path of the breaking member connects between the external electrode and the support, a conductive lid is fixed to the open end of the electrode case. If a first packing is provided between the lid and the support and seals the two, the insulation between the external electrode and the lid, which have opposite polarities, can be secured, and the inside of the storage battery is kept airtight. be able to.

Further, by disposing a second packing which is located between the support and the operating member and seals between them, the operating member can be made of a conductive material and the inside of the storage battery is airtight. In particular, the first and second packings can be integrated into a second
When the packing of (1) is folded back and positioned between the support and the operating member, the assembling workability is improved.

[0018]

EXAMPLES Examples will be described with reference to the drawings.
1 is a longitudinal sectional view of a pressure cutoff sensor according to a first embodiment of the present invention, and FIG. 2 is an exploded perspective view of the pressure cutoff sensor.

In FIGS. 1 and 2, reference numeral 1 denotes a pressure cutoff sensor, which is a gasket 2, leads 3, 4a, 4b, actuator 5, packing 6, cutoff element 7, cutoff element holder. 8, PTC
Element (positive temperature coefficient thermisto
r) 9 and external electrodes 10 are mainly included.

The gasket 2 is made of an insulative PP (polypropylene) material, and is composed of a cylindrical portion 2b having an open top surface and a bottom plate portion 2a. The center of the bottom plate portion 2a is a battery when mounted on a storage battery. A round hole portion 2c communicating with the inside and a cutout portion 2d that is cut outward from the peripheral edge of the round hole portion 2c and leads 3 to the lower side (inside the battery) are provided. An actuator 5 is mounted inside the gasket 2.

The actuator 5 is made of a conductive aluminum material and is formed into a substantially disk shape as a whole. The outer peripheral portion of the actuator 5 is a flange portion 5a which is closely adhered to the bottom plate portion 2a of the gasket 2 and a central portion thereof. A safety valve portion 5b which is formed to bulge upward in a conical shape having a flat head and has a recess 5c for a safety valve on the flat surface, and a shut-off element projectingly provided at the center of the flat surface of the head of the safety valve portion 5b. It is composed of a breaking projection 5d. The lead 3 is welded to the lower surface of the flange portion 5a of the actuator 5, and the lead 4b is welded to the upper surface of the flange portion 5a.
The safety valve portion 5b has a safety valve concave portion 5c to function as a safety valve, and also has a shut-off element breaking projection 5d.
It also functions as a pressure-sensitive part. A packing 6 is mounted on the actuator 5.

The packing 6 is made of an insulating rubber material,
It is formed in a substantially disc shape as a whole. The packing 6 has an annular projection 6a formed on the outer peripheral edge thereof, a round hole 6b formed in the center, an annular projection 6c formed on the periphery of the round hole 6b, and a round hole. A notch 6d for leading the lead 4 formed by notching from the edge of 6b;
It is composed of a bottom plate portion 6e. A blocking element 7 is arranged above the round hole 6b of the packing 6.

The blocking element 7 is a substrate 7a made of an insulating ceramic or resin, and a blocking circuit 7 formed by printing on the upper surface of the substrate 7a or adhering a metal foil.
b, and leads 4 are provided at both ends of the breaking electric circuit 7b.
a and 4b are connected to each other and these leads 4
a and 4b are fixed to the substrate 7a. One lead 4a is arranged on the bottom plate portion 6e of the packing 6 and connected to the lower surface of the PTC element 9. Therefore, the lead 4a is sandwiched on the bottom plate portion 6e of the packing 6 and the PTC element 9 is inserted. Are arranged. Also, the other lead 4
b is routed from the notch 6d of the packing 6 to the lower surface side of the bottom plate 6e of the packing 6, that is, the upper surface of the flange 5a of the actuator 5, and as described above, the lead 4b.
And the flange portion 5a of the actuator 5 are welded together.

The PTC element 9 is formed in a disc shape and has a round hole 9a formed in the center thereof. This PTC element 9 acts so that its conduction resistance value increases and the current decreases when the temperature rises. For example, the conduction resistance value in the steady state is set to 20 mΩ and the current control temperature is set to +120 degrees. There is.

The blocking element holder 8 is made of a thermoplastic resin, and has an upper plate portion 8a, a pair of leg portions 8b and 8b extending downward from both ends of the upper plate portion 8a, and inner surfaces of the pair of leg portions 8b and 8b. Of the holding elements 8c, 8c, which are provided so as to project toward the upper surface of the blocking element 7 and support the blocking element 7 when the blocking element 7 is pushed from below. A gap is formed between the upper plate portion 8a of the blocking element holder 8 and the upper surface of the blocking element 7 so that the blocking element 7 can be bent. The blocking element holder 8 is in the round hole 9a of the PTC element 9, and the lower end surface of one foot portion 8b of the blocking element holder 8 is arranged on one lead 4a and the other foot portion 8b. The lower end surface of 8b is arranged on the bottom plate portion 6e of the packing 6.

The external electrode 10 serves as a positive electrode of the storage battery when the pressure cutoff sensor 1 is incorporated into the storage battery, and is made of nickel, stainless steel or the like. The external electrode 10 includes a flange 10a on the outer periphery, a bulge 10b in the center, and a plurality of safety valve openings 10c, 1 formed on the inclined side surfaces of the bulge 10b.
0c ... Then, the external electrode 10
1, the lead 3, 4a, 4b, the actuator 5, the packing 6, the blocking element 7, the blocking element holder 8 and the PTC element 9 are assembled in the gasket 2, and further covered from above and sandwiched, as shown in FIG. On the gasket 2
The upper part of the cylindrical part 2b is fixed by caulking the inside. In the state of FIG. 1, the pressure cutoff sensor 1 is assembled and completed. The above-described crimping of the pressure cutoff sensor 1 of FIG. 1 is a tentative crimping, and the pressure cutoff sensor 1 is assembled into a storage battery as shown in FIG. it can.

FIG. 3 is an explanatory view showing a schematic structure of the pressure cutoff sensor 1 assembled as described above, which is incorporated in a storage battery 40 such as a lithium ion secondary battery or a nickel hydrogen secondary battery.

In FIG. 3, reference numeral 41 denotes a bottomed cylindrical battery case having an open upper end. This battery case 41 serves as an external negative electrode of the storage battery 40, and an opening edge of the upper end thereof serves as a caulking portion 41a. Has been done. Reference numeral 48 is a winding core, 49 is a power generation unit configured by winding a positive electrode and a negative electrode around the winding core 48, and 50 is a negative electrode of the power generation unit 49 and an external negative electrode (battery case).
41 is a lead for connecting with 41. The power generation unit 49 incorporates a positive electrode made of lithium cobalt oxide, a negative electrode made of carbon, and a separator for preventing a short circuit between the positive electrode and the negative electrode, and the negative electrode is provided so as to face the positive electrode with the separator interposed therebetween. . Further, the inside of the battery case 41 is filled with an electrolytic solution (not shown).

Next, a method of incorporating the pressure cutoff sensor 1 into the storage battery 40 will be described. Before assembly, battery case 41
The caulking portion 41a has a cylindrical shape as shown by the alternate long and short dash line in FIG. The pressure cutoff sensor 1 shown in FIG. 1 is inserted into the battery case 41 from above. In this state,
As described above, the cylindrical portion 2b of the gasket 2 of the pressure cutoff sensor 1 is in the temporarily crimped state. And the battery case 4
The cylindrical portion 2b of the gasket 2 is crimped inside together with the crimping portion 41a of No. 1 to perform main crimping. In this way, FIG.
As shown by the solid line in FIG.
By caulking the cylindrical portion 2b of the gasket 2 over the entire circumference, the pressure cutoff sensor 1 is reliably incorporated into the storage battery 40 and sealed.

Next, the operation when the first embodiment is used in the lithium ion secondary battery, that is, in the use state of FIG. 3, will be described. During charging, the current in the pressure cutoff sensor 1 is sequentially supplied from the external electrode (positive electrode) 10.
The PTC element 9, the lead 4a, the breaking electric path 7b of the breaking element 7, the lead 4b, and the actuator 5 flow to the lead 3. That is, the current flows from the external electrode 10 to the PTC element 9 and the lead 4a, and the breaking electric circuit 7b on the upper surface of the breaking element 7 connected to the lead 4a.
Through the lead 4b connected to the breaking electric path 7b, and further led from the lead 4b to the actuator 5 and the lead 3. At this time, even if charging is completed, if current continues to flow and overcharging is further performed, or if charging is performed with a current larger than the specified current, the storage battery 4
0 occurs and the pressure and temperature inside the storage battery 40 rise.

When the pressure in the storage battery 40 rises, it is transmitted to the pressure cutoff sensor 1 as an external pressure. Then, as shown in FIG. 3, this external pressure bends the safety valve portion 5b of the actuator 5 upward through the round hole portion 2c of the gasket 2 and deforms the safety valve portion 5b of the actuator 5 for breaking the shut-off element at the center. The protrusion 5d is the blocking element 7
Push the middle part of the upward. Both ends of the blocking element 7 are provided with holding projections 8c, 8 of the blocking element holder 8.
Since it is supported by c, when the pressure in the storage battery 40 further rises and reaches a certain pressure, the substrate 7a of the shut-off element 7 is fixed to the shut-off element breaking projection 5d of the actuator 5. It is further deformed by receiving pressure, and the blocking element 7 is the upper plate portion 8 of the blocking element holder 8.
It is pushed into the gap below and cracks. Due to the breakage of the breaking element 7, the breaking electric path 7 of the breaking element 7
When b is disconnected and the electrical connection between the leads 4a and 4b is cut off, the pressure cutoff sensor 1 cuts off the current flowing between the external electrode 10 and the positive electrode of the power generation section 49, and stops further charging. At the same time, this lithium-ion secondary battery is put into a state in which it cannot function as a storage battery.

Further, when the pressure in the storage battery 40 further rises, the safety valve recess 5c of the safety valve portion 5b of the actuator 5 is broken, and the gas in the storage battery 40 becomes the safety valve recess 5c.
The external electrode 10 through the pressure cut-off sensor 1
Are discharged from the safety valve openings 10c, 10c. For example, the operating pressure of the pressure cutoff sensor 1 is operated in the range of 4 to 10 atmospheres, and the safety valve operating pressure is operated in the range of 10 to 20 atmospheres.

When the temperature inside the storage battery 40 becomes abnormally high, the conduction resistance value of the PTC element 9 increases and the current value decreases.

In the first embodiment thus constructed, the safety valve portion 5b is fixed to the battery case 41 to seal the inside of the storage battery 40 and is displaced outward due to an increase in pressure inside the storage battery 40. Conductive actuator 5 having (pressure sensitive portion) and external electrode 10 serving as a positive electrode of storage battery 40
And a conductive path 7b located outside the actuator 5 when fixed to the battery case 41, one end of which is connected to the external electrode 10 and the other end of which is connected to the actuator 5. Since the breaking element 7 that breaks and blocks the conductive path 7b is provided, safety can be improved, and even if an inflammable gas is generated due to an internal abnormality, the broken part of the conductive path 7b is Storage battery 40
Since it is on the outside, there is no fear of ignition even if the arc flies when the breaking element 7 breaks.

Further, in the first embodiment, the conductive path 7
Since the PTC element 9 is provided between the electric path between b and the external electrode 10, the current can be reduced when the temperature becomes abnormally high, and the safety against heat can be improved.

Further, in the first embodiment, the external electrode 10 has the opening 10c and the actuator 5 has the safety valve portion 5b (safety valve). Therefore, the mechanism also functions as an explosion-proof mechanism in an emergency. Can be simplified and cost can be reduced.

Further, in the first embodiment, since the safety valve portion 5b has the functions of both the pressure sensing portion and the safety valve,
The reliability can be further improved, and the pressure at which the shut-off element 7 is activated (broken) and the safety valve portion 5b are activated by combining the functions of both the pressure sensing portion and the safety valve (the safety valve recess). It becomes easier to manage the pressure and the pressure at which 5c breaks.

Further, in the first embodiment, the external electrode 10 is provided with the bulging portion 10b projecting outward, and the blocking element 7 is housed in the bulging portion 10b, so that the space can be saved. The capacity of the storage battery 40 as a whole can be increased.

FIG. 4 is a plan view showing a pressure cutoff sensor according to a second embodiment of the present invention, FIG. 5 is a vertical sectional view of the pressure cutoff sensor, FIG. 6 is a bottom view of the pressure cutoff sensor, and FIG. 1 is an exploded perspective view of the pressure cutoff sensor, FIG. 8 is a cross-sectional view taken along the line AA of FIG. 4, and FIG. 9 is a cross-sectional view taken along the line BB of FIG.
0 is a cross-sectional view taken along the line CC of FIG.

4 to 10, reference numeral 21 denotes a pressure cutoff sensor, and the pressure cutoff sensor 21 has a substantially rectangular overall shape, and has an actuator 22, a cutoff element 23, a lead 24, and a support. Body 25, packing 26, lid 27, holding case 28 and external electrode 2
It is mainly composed of 9.

The actuator 22 is made of a conductive aluminum material like the actuator 5 in the first embodiment, and is formed in a substantially rectangular shape as a whole. The actuator 22 has a ridge 22a formed on its outer peripheral edge.
And a flat plate-shaped flange portion 22b, and this flange portion 22
An annular recess 22c formed by a thin portion having a substantially elliptical shape in the center of b, and a safety valve portion 22d in the annular recess 22c.
And a breaking projection 22e for breaking the shut-off element 23 protruding from the center of the safety valve portion 22d. The outer peripheral portion of the safety valve portion 22d (the area surrounded by the broken line in FIG. 7) is partially heat-treated to soften its hardness, thereby improving the diaphragm characteristics. As a heat treatment method, heat may be directly applied to the portion of the safety valve portion 22d to be softened, ultrasonic waves may be applied to the portion, or Joule heat due to resistance may be applied, and the heat treatment temperature is 200 to 500 ° C. 3 to 10 seconds.

The shut-off element 23 has a substantially strip shape, and like the shut-off element 7 in the first embodiment, a substrate 23a made of an insulating ceramic or resin and a print molding on the upper surface side of the substrate 23a. Cut-off circuit 23
b and. Leads 24a and 24b are respectively connected to both ends of the breaking electric circuit 23b in the longitudinal direction.

The support 25 is made of a conductive aluminum material, and is formed by integrally raising a support surface portion 25b having a substantially rectangular opening 25a in the center and an outer peripheral portion of the opening 25a. Upper ridge 2
5c and the lower protrusion 2 formed by integrally lowering downward so as to surround the outer peripheral portion of the support surface portion 25b.
5d and a terminal portion 25e having a substantially U shape. The upper protrusion 25c is provided with two protrusions 25f on the longitudinal side and one protrusion 25f on the lateral side. On the other hand, similarly, for the lower protrusion 25d, two are provided on each of the longitudinal sides and one is provided on each of the lateral sides.
Two caulking projections 25g are formed. Terminal part 25
Notches 25h are formed at both ends of the U-shape of "e", and the notches 25h cause the caulking projection 25g.
The terminal portion 25e is connected to both ends of the lower protrusion 25d in the longitudinal direction so as to avoid. As shown in FIGS. 5, 7 and 8, the terminal portion 25e is finally bent at a substantially right angle. In addition, a lead connecting portion 25i is provided at one end in the longitudinal direction of the opening 25a, and one lead 24b is connected to the lead connecting portion 25i.

The packing 26 is made of synthetic resin such as ethylene propylene copolymer (EPDM) or rubber material having insulation and elasticity, and is an upper packing that seals between the support 25 and the lid 27. Part 26a and support 25
And a lower packing portion 26b that seals between the actuator 22 and the actuator 22. Upper packing part 2
6a is an opening for inserting a rectangular flat plate portion 26c having a size substantially covering both end portions of the terminal portion 25e, and an upper protrusion 25c of the support body 25 formed at a substantially central portion of the flat plate portion 26c. 26d and an upper protrusion 26e formed by integrally rising upward so as to surround the outer peripheral portion of the opening 26d. Lower packing part 26b
Is integrally connected to the upper packing portion 26a through three connecting portions 26f that are spaced apart, and the outer shape thereof is sized to fit into the lower protrusion 25d, and the central portion is Has a rectangular opening 26g.
Pressing projections 26h for pressing both ends of the blocking element 23 are provided on both sides of the opening 26g in the lateral direction. On the lower surface of the lower packing part 26b, a pressing projection 26i for pressing the connection part between the breaking element 23 and the leads 24a, 24b is provided in a protruding manner.

The lid 27 is formed of a conductive metal plate such as a stainless material, and the upper packing portion 2 of the packing 26.
6a has a size enough to cover the top of the 6a, and an opening 27a through which the upper protrusion 26e is inserted is formed at a substantially central portion thereof.
An annular protrusion 27b is formed on the outer peripheral portion so as to protrude upward.

The holding case 28 is made of an insulating resin such as polyacetal, and is sized to fit in the protrusion 27b of the lid 27. From the opening 27 a of the lid 27 to the opening 2 of the support body 25, in the substantially central portion of the lower surface of the holding case 28.
A pair of leg portions 28a are inserted so as to project into the 5a. The holding case 28 above the pair of legs 28a has a pedestal portion 28b holding an external electrode 29.
Are integrally formed. The holding case 28 also has
An opening 28c into which a connecting portion 29b of an external electrode 29, which will be described later, is inserted, and a slit 28d into which the caulking claw 29c of the external electrode 29 and the six protrusions 25f of the support body 25 are respectively inserted are provided.

Like the external electrode 10 in the first embodiment, the external electrode 29 serves as a positive electrode of the storage battery 40 when the pressure cutoff sensor 21 is incorporated in the storage battery 40 (see FIG. 5), and is made of nickel or stainless steel. Made of wood.
The external electrode 29 includes a substantially rectangular main body portion 29a and a connecting portion 29 that is bent stepwise from one side edge of the main body portion 29a.
b, an end edge from which the connecting portion 29b extends, and a pair of caulking claws 29c formed so as to hang down from the end edge opposite to the end edge.

Pressure cutoff sensor 2 according to the second embodiment
In the first example, first, the blocking element 23 to which the leads 24a and 24b are connected is arranged in the support 25, and then the packing 26 is placed so that the upper packing portion 26a covers the flat plate portion 26c of the support 25. . And packing 2
The lower packing portion 26b of No. 6 is bent downward from the connecting portion 26f, and the lower packing portion 26b is positioned below the support 25. At this time, each connecting part 2
If the caulking projection 25g of the support 25 is passed through the gap between the 6f, it can be folded small from the connecting portion 26f. Next, after the actuator 22 is positioned so as to be applied to the lower packing portion 26b, the caulking protrusion 2
By caulking 5 g, the outer peripheral edge of the actuator 22 is pressure-bonded to the lower packing portion 26.

On the other hand, the pedestal portion 28b of the holding case 28 holds the external electrode 29, the connecting portion 29b of the external electrode 29 is inserted into the opening 28c of the holding case 28, and the caulking claw 29c is inserted into the slit 28d. As a result, the connecting portion 29b of the external electrode 29 can be connected to the lead 24a. Then, after placing the lid 27 on the upper packing portion 26a of the packing 26, the holding case 28 to which the external electrode 29 is attached is fitted into the protrusion 27b of the lid 27. The lid 27 and the holding case 28 are fixed by fixing the protrusion 25f of the support 25 to the slit 28d of the holding case 28.
It is done by caulking after inserting into.

The pressure cutoff sensor 21 assembled in this way is similar to the first embodiment in that the lithium ion 2
It is used by being incorporated into a storage battery 40 such as a secondary battery or a nickel hydrogen secondary battery. At that time, as shown in FIG. 5, in the pressure cutoff sensor 21, the outer peripheral edge of the lid 27 is caulked to the upper open end of the battery case 41, so that the storage battery 4 is discharged.
0 is installed, the lid 27 and the battery case 41 are
It is an external negative electrode of 0.

Next, the operation when the second embodiment is used in the lithium ion secondary battery will be described. During charging, the current in the pressure cutoff sensor 21 is sequentially read from the external electrode (positive electrode) 29. 24a, the breaking electric circuit 23b of the breaking element 23, the lead 24b and the support 25, and is led to the terminal portion 25e. When the storage battery 40 to which the pressure cutoff sensor 21 is attached is overcharged or an abnormality occurs and the pressure or temperature in the storage battery 40 rises, the safety valve portion 22d of the actuator 22 bends upward and is broken. The projection 22e is a blocking element 23
To break the disconnecting electric circuit 23b to disconnect the lead 24
The connection between a and 24b is cut off. Further, when the pressure further rises, the actuator 22 is driven as in the first embodiment.
The safety valve portion 22d of the external electrode 10 is ruptured and passes through the pressure cutoff sensor 21, and the safety valve openings 10c, 10c ...
Emitted from.

In the second embodiment constructed as described above, the actuator 22 has only the function of sensing the pressure in the storage battery 40, and it is not necessary to form a conductive path. Therefore, the structure is simplified. It is also possible to use a material other than metal. In addition, by packing 26, the space between the actuator 22 and the support 25 and the support 2
5 and the lid 27 are reliably insulated, and the inside can be kept airtight. Moreover, since the packing 26 interposed between the two is positioned by bending from the connecting portion 26f, only one packing is required, and the number of parts can be reduced.

Further, in the second embodiment, since the safety valve portion 22d of the actuator 22 is softened by the partial heat treatment, the safety valve portion 22d extends from the annular recess 22c.
It is possible to surely displace the portion up to the outer peripheral portion of the, but it is possible to secure sufficient strength for breaking the blocking element 23 in the other protrusions 22a, the flange portion 22b or the breaking projection 22e. Therefore, it is possible to satisfy the contradictory characteristics of good diaphragm characteristics and sufficient strength at the same time.

Although the holding case 28 is arranged outside the lid 27 in the second embodiment, this holding case 2
8 is disposed on the lower surface of the support 25, and the external electrodes 29 are provided on the support 25, the packing 26, and the openings 25a of the lid 27,
You may make it project outside from 26d and 27a. In addition, a PTC element can be arranged between the external electrode 29 and the blocking element 23, if necessary.

[0055]

The present invention is carried out in the form as described above, and has the following effects.

An external electrode which is one of the electrodes of the battery, and a conductive actuating member having a pressure sensitive portion which is fixed in the battery case in a hermetically sealed state via an insulator and is displaced outward due to an increase in pressure inside the battery. , Located outside the actuation member when fixed to the battery case, has a conductive path having one end connected to the external electrode and the other end connected to the actuation member, and broken by displacement of the pressure-sensitive portion By providing the breaking member for breaking the conductive path, even if the arc should fly at the time of breaking the breaking member, the gas inside the storage battery will not be ignited by the arc, so that the safety is high. An interruption sensor can be provided.

Further, an external electrode which is one of the electrodes of the battery, an operating member which is fixed in a hermetically sealed state inside the battery case and has a pressure sensitive portion which is displaced outward due to an increase in pressure inside the battery, and fixed to the battery case. Then, a conductive support located outside the operating member and having an electric path to the inside of the battery, an insulating holding member for holding the external electrode, and a conductive connection between the external electrode and the support. By having a breaking member that has a path and is broken by the displacement of the pressure-sensitive portion and interrupts the conductive path, the actuating member has only the function of breaking the breaking member by displacement, and is not necessarily conductive. Is not necessary, the degree of freedom of the shape and material of the operating member is increased, and the structure is simplified.

Further, by disposing the PTC element between the electric path between the conductive path and the external electrode, the current can be reduced when the temperature becomes abnormally high, and the safety against heat can be improved.

If an opening is provided in the external electrode and a pressure sensitive portion and a safety valve are provided in the actuating member, the mechanism can be simplified and the cost can be reduced by using the explosion-proof mechanism in an emergency. In particular, if the safety valve also serves as the pressure sensitive portion, it becomes easy to simultaneously manage the pressure at which the breaking member operates and the pressure at which the safety valve operates.

If the external electrode is provided with a protrusion projecting outward and the breaking member is housed in the protrusion, space can be saved and the capacity of the storage battery as a whole can be increased.

If a portion softened by heat treatment is formed on the actuating member and the portion surrounded by the softened portion is used as the pressure sensitive portion, an actuating member that displaces in response to a change in internal pressure quickly is provided. realizable.

When the battery case is the other electrode of the battery and the conductive path of the breaking member connects between the external electrode and the support, a conductive lid is fixed to the open end of the electrode case. If a first packing is provided between the lid and the support and seals the two, the insulation between the external electrode and the lid, which have opposite polarities, can be secured, and the inside of the storage battery is kept airtight. be able to.

Further, by disposing a second packing located between the support and the actuating member and hermetically sealing them, the actuating member can be made of a conductive material and the inside of the storage battery is airtight. In particular, the first and second packings can be integrated into a second
When the packing of (1) is folded back and positioned between the support and the operating member, the assembling workability is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a pressure cutoff sensor according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the pressure cutoff sensor.

FIG. 3 is an explanatory diagram showing a schematic configuration in a state in which the pressure cutoff sensor is used in a lithium ion secondary battery.

FIG. 4 is a plan view of a pressure cutoff sensor according to a second embodiment of the present invention.

FIG. 5 is a vertical sectional view of the pressure cutoff sensor.

FIG. 6 is a bottom view of the pressure cutoff sensor.

FIG. 7 is an exploded perspective view of the pressure cutoff sensor.

8 is a cross-sectional view taken along the line AA of FIG.

9 is a cross-sectional view taken along the line BB of FIG.

10 is a cross-sectional view taken along the line CC of FIG.

FIG. 11 is an explanatory diagram showing a schematic configuration of a conventional pressure cutoff sensor.

[Explanation of symbols]

1,21 Pressure cutoff sensor 5,22 actuator 5b, 22d Safety valve section 5c Safety valve recess 7,23 Blocking element 7b, 23b Breaking circuit 9 PTC element 10, 29 External electrode 10b bulge 10c opening 24 leads 25 support 26 packing 26a Upper packing part 26b Lower packing part 27 Lid 27a opening 28 holding case 40 storage battery 41 battery case

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01M 2/34 H01M 10/42-10/48

Claims (10)

(57) [Claims] 1. An electrically conductive operation having an external electrode which is one of electrodes of a battery and a pressure-sensitive portion which is fixed in a battery case in a hermetically sealed state via an insulator and is displaced outward due to an increase in pressure inside the battery. A member and a conductive path located outside the actuation member when fixed to the battery case, having one end connected to the external electrode and the other end connected to the actuation member; And a breaking member that breaks the conductive path to break the conductive path. 2. An external electrode which is one of electrodes of a battery, an operating member which is fixed in a sealed state in the battery case, and has a pressure sensitive portion which is displaced outward due to an increase in pressure inside the battery, and fixed to the battery case. When located at a position outside the actuating member, a conductive support having an electric path to the inside of the battery, an insulating holding member for holding the external electrode, and a conductive connection between the external electrode and the support. Have a road,
And a breaking member that breaks due to displacement of the pressure-sensitive portion and breaks the conductive path. 3. The pressure cutoff sensor according to claim 1 or 2, wherein a PTC element is provided between the conductive path and the external electrode. 4. The pressure cutoff sensor according to claim 1, wherein the external electrode has an opening, and the operating member has a safety valve. 5. The pressure cutoff sensor according to claim 4, wherein the safety valve also serves as a pressure sensitive portion of the operating member. 6. The pressure cutoff sensor according to claim 1, wherein the external electrode has a protrusion protruding outward, and the breaking member is housed in the protrusion. . 7. The pressure cutoff according to claim 1, wherein a portion softened by heat treatment is formed on the actuating member, and a portion surrounded by the softened portion serves as the pressure sensitive portion. Sensor. 8. The conductive lid body according to claim 2, wherein the battery case is the other electrode of the battery, and is fixed to an open end of the battery case and has an opening through which the external electrode projects. A pressure cutoff sensor comprising: a first packing which is located between the lid and the support and seals between the two. 9. The operating member according to claim 8, wherein the actuating member is made of a conductive material, and is provided with a second packing that is located between the support and the actuating member and seals between the two. Pressure cutoff sensor. 10. The pressure according to claim 9, wherein the first packing and the second packing are integrated, and the second packing is folded back to be positioned between the support and the actuating member. Cutoff sensor.