JPH08315797A - Safety device of battery - Google Patents

Abstract

PURPOSE: To put electric continuity cutting-off pressure in a prescribed narrow range in the first place, put partition wall rupturing pressure in a prescribed small range in the second place, and reduce manufacturing cost of a product in the third place. CONSTITUTION: In a safety device of a battery which is provided with a conductive partition wall 21 to shield an opening of a battery vessel 1 and a conductive contact conductor 22 which is fixed to the vessel 1 on the central part vicinity inside of the partition wall 21 and electrically continues with an internal electrode, and in which cutoff of electric continuity between the partition wall 1 and the contact conductor 22 and a rupture of the partition wall 21 are caused by the increase in internal pressure, the contact conductor 22 has a contact point projection 22d which projects so as to be opposed to the partition wall 21 and is electrically continued by contacting with this, and also has a rupturing edge part 29 opposed to an outside surface of the partition wall 21. As an effect, in the first place, the joining area is regulated by the contact point projection 22d, and electric continuity cutting-off pressure becomes constant. In the second place, partition wall rupturing pressure is also made constant by the edge part 29. In the third place, since a part shape is simple and assembling is easy, cost is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for preventing a battery from bursting, and more specifically, a container sealed even when the internal pressure of the battery abnormally rises due to a circuit short circuit, overcharge, overheat, or the like. The present invention relates to a battery safety device that prevents a battery with a battery from bursting and thus protects the safety of the device containing the battery and the person carrying it.

[0002]

2. Description of the Related Art As a conventional battery safety device, there is one disclosed in, for example, Japanese Patent Laid-Open No. 288063. In the battery equipped with the safety device of the publication, the upper opening of the case is shielded by a conductive partition (“safety valve” in the publication), and the partition is welded to the lead plate and is attached to one electrode of the battery through the lead plate. There is continuity. The lead plate is fixed to the case, and when the internal pressure of the battery rises, the lead plate is separated from the partition wall or the lead plate is broken and the energization from the partition wall to the electrode (usually the positive electrode) is cut off. If the pressure continues to rise after that, a crack is formed in the groove (thin portion) formed in the partition wall, and the internal pressure is released before the burst pressure of the battery container is reached.

[0003]

In the safety device of the above publication, the partition walls are stacked on the lead plate or the welding plate in upper and lower two layers and the joint surfaces of the both are welded, and the lead plate or the welding plate peels off when the power is cut off or It has a structure that breaks. It should be noted that the partition wall that is displaced by the internal pressure must be completely separated from the welding plate (or lead plate) in order to reliably cut off energization.Therefore, the partition wall may break before the lead plate or welding plate is peeled or damaged. The rise in internal pressure must not end. For this reason, the partition wall needs to have strength enough to withstand the stress at the time of peeling or breakage. On the other hand, the partition wall is also required to have a function of avoiding further increase in internal pressure by being damaged by the subsequent increase in internal pressure.

However, in the above-mentioned prior art, if the partition wall is made thicker or a high-strength material is used to provide the partition wall with a strength to withstand the stress at the time of peeling or breakage, the rigidity of the partition wall increases and the internal pressure increases. The resistance force against the displacement of the partition wall against the rise is increased, which reduces the force applied to the welded portion, and as a result, the welded portion is not separated or damaged despite a large increase in the internal pressure. In addition, if the partition wall is thickened or a high-strength material is used as described above, and the partition wall is provided with strength to withstand the stress at the time of peeling or damage, further increase in internal pressure after the peeling or damage of the welded portion is achieved. This makes it difficult for the partition to be displaced or damaged.

On the contrary, for example, the partition wall and the welding plate (or lead plate) may be formed by thinning the partition wall or adopting a low-strength material.
If the separation of the lead plate and the weld plate is facilitated, the partition wall will break when the lead plate or the welded plate is peeled off or damaged. Further, since the above-mentioned partition wall has a three-dimensional shape on the welding surface, that is, the current-carrying portion, it is not easy to manufacture and join, and there is a problem that the operating pressure varies widely.

In summary, the battery safety device according to the above-mentioned prior art has the following three problems to be solved. First, since it is difficult to adjust the pressure at which conduction and interruption between the lead plate and the partition wall occur, and there is a large variation between products, it is difficult to keep the conduction and interruption pressure within a predetermined narrow range. This is also due to the fact that in the manufacturing process of the protrusions that become the contact points of the partition walls, the drawing precision does not provide the processing accuracy.

Secondly, since the means for releasing the internal pressure by breaking the partition wall is formed by making a crack in the groove (thin portion) formed in the partition wall, the breaking pressure cannot be set constant. It was difficult. That is, since the breaking pressure depends on a slight difference in the wall thickness and surface shape of the groove, there is a large variation between products, and it is difficult to keep the breaking pressure within a predetermined narrow range.

Thirdly, a part having a complicated shape such as an intermediate fitting body having a fitting groove formed on the inner peripheral surface thereof, and a partition wall (safety valve) having a circular groove and a linear groove formed on a press work. was there. Therefore, there is also a problem that the cost cannot be manufactured at a low cost when the cost of parts and the cost of assembly and processing are added together. The battery safety device of the present invention has been made in view of the above problems, and has the following three problems to be solved.

That is, firstly, the conduction breaking pressure can be kept within a predetermined narrow range, secondly, the breaking pressure of the partition wall can be kept within a predetermined narrow range, and thirdly, the manufacturing cost of the product can be reduced. It is to be.

[0010]

According to a first aspect of the present invention, there is provided a battery safety device including a conductive partition wall that shields an opening of a container containing a battery electrode and an electrolytic solution, and a central portion of the partition wall. A conductive contact conductor that is fixed to the container and is electrically connected to the electrode while being located inside, and blocking the conduction between the partition wall and the contact conductor and breaking the partition wall of the container. In the battery safety device generated by the displacement of the partition wall due to the increase in the internal pressure, the contact conductor has a contact protrusion that projects toward the inner side surface of the partition wall and contacts the wall surface to conduct electricity.

Here, the type of battery may be any type of battery as long as it has a sealed container containing a chemical substance having an electromotive force, and it does not matter whether it is a primary battery or a secondary battery. . When the conductive partition walls and the contact conductors are both members on the positive electrode side of the battery, it is suitable to use aluminum, aluminum alloy, nickel, nickel alloy, stainless steel, or the like.

According to a second structure of the present invention, further, in the first structure, it is fixed directly or indirectly to the container and faces at least a predetermined distance near the central portion of the outer surface of the partition wall. It is characterized by having one breaking blade. Here, a supporting member for supporting the blade portion with respect to the container may be provided, and in that case, the supporting member needs an opening or a gap for allowing the internal pressure to escape to the outside air.

A third structure of the present invention is characterized in that, in the first structure or the second structure, the contact protrusion has a joining plane formed at the top portion in parallel with the inner side surface of the partition wall. . Here, it is also possible to adopt a configuration in which the contact protrusion is formed in a right cylindrical shape for the purpose of precisely making the area of the bonding plane.

According to a fourth structure of the present invention, in any one of the first to third structures, the contact conductor and the partition wall are
Welding, brazing, soldering at the top of the contact protrusion,
It is characterized in that they are joined to each other by either means of welding or fusion welding. According to a fifth aspect of the present invention, in any one of the first to third aspects, the contact conductor and the partition wall are biased by a spring elastic force of the partition wall and are in contact with each other with a pressing force. Characterize.

According to a sixth aspect of the present invention, in addition to the fifth aspect, the electrical conductivity and the acid resistance are provided on at least one surface of the top of the contact protrusion and the contact portion inside the partition wall with which the top contacts. It is characterized in that a conductor layer having excellent chemical resistance and corrosion resistance is formed. Here, as the material for forming the conductor layer, gold, gold alloy, platinum, platinum alloy, silver, silver alloy, copper, copper alloy and other metals or alloys can be used.

A seventh structure of the present invention is the above first to sixth structures.
The configuration is further characterized in that an electrolyte solution absorber held directly or indirectly in the container is provided outside the partition wall. Here, as the material of the electrolytic solution absorber, a material suitable for the property of the liquid (electrolytic solution or the like) that may leak from the battery is used. For example, various sponges, porous paper materials (blotting paper, etc.), and polymeric water absorbing materials (used in sanitary products, diapers, etc.) can be used.

[0017]

In the first structure of the present invention, the only parts related to the conduction and interruption are the contact conductor and the partition wall,
Since the contact conductors are brought into contact with the partition wall by the contact protrusions protruding from the contact conductor, the joint area at the contact portion is limited. Therefore,
According to this configuration, since the area of the joint is constant, the value of the internal pressure (conduction interruption pressure) at which the contact conductor and the partition are separated from each other and conduction is lost falls within a substantially constant limited range. There is an effect. In addition, since the shape of the component parts is simple, the cost of parts and the assembly and processing cost can be reduced, and the manufacturing cost of the product can be reduced.

In the second structure of the present invention, since the partition wall displaced by the increase of the internal pressure has the breaking blade portion for opening the breaking hole,
The pressure at which the incision of the rupture starts is determined by the displacement of the partition wall, which has a precise correlation with the internal pressure (more correctly, the differential pressure of the internal pressure with respect to the external pressure). Therefore, according to this configuration, when the contact conductor and the partition are separated from each other and the internal pressure further rises beyond the conduction cutoff pressure at which conduction is lost, the internal pressure can be reliably released by opening the breakage in the partition. . Then, there is an effect that the partition wall rupture pressure at that time can be contained within a certain range relatively accurately.

In the third structure of the present invention, the contact projection has the bonding plane at the top thereof and is bonded to the partition here, so that the bonding area is completely limited to a constant value. Therefore, according to this configuration, there is an effect that the dispersion of the bonding strength is reduced regardless of which bonding means is used and the conduction breaking pressure can be set extremely accurately (within a predetermined narrow range).

In a fourth structure of the present invention, the joining means is
Since it is any one of welding, brazing, soldering, welding, and fusion welding, the required conduction between the contact conductor and the partition wall is reliably ensured. Therefore, according to the present configuration, there is an effect that defective products due to a conduction defect between the contact conductor and the partition wall are not generated. Furthermore, if properly managed, products with consistent bonding strength and no variations can be supplied.

Therefore, according to this configuration, the quality of the product is made constant, the defective product rate is reduced, and as a result, the manufacturing cost of the product can be further reduced. In the fifth configuration of the present invention, since the contact conductor and the partition are in contact with each other due to the spring elastic force of the partition, the two are separated from each other and lose conduction due to a precise internal pressure value as in the spring scale. Therefore, according to this configuration, there is an effect that the conduction cutoff pressure can be precisely controlled.

In the sixth structure of the present invention, since a conductive layer that is resistant to oxidation and has good conduction is formed on the surface of the contact (or the joining plane), conduction at the contact becomes more reliable and oxidation or oxidation is prevented. Conduction failure due to corrosion etc. is less likely to occur. Therefore, according to this structure, there is an effect that it is possible to provide a more reliable product while maintaining a precise conduction / breaking pressure as in the fifth structure.

In the seventh configuration of the present invention, the electrolytic solution absorber is provided inside the battery container (or lid or outer lid) outside the partition wall. Therefore, when a breakage occurs in the partition wall and the internal pressure escapes,
Even when a liquid such as an electrolytic solution or powder is mixed and blown out into the gas, it does not leak to the outside of the battery by being absorbed by the electrolytic solution absorber or filtered. Therefore, according to this configuration, even if the internal pressure is abnormally increased and a gas vent rupture occurs in the partition wall due to the operation of the safety device, it is possible to prevent the contents such as the electrolyte from leaking out and damaging the surrounding devices. Has the effect of

[0024]

【Example】

[Example 1: Welding to partition wall at joint plane on contact protrusion top of contact conductor] (Structure of Example 1) The structure of the battery safety device as Example 1 of the present invention is mainly as shown in FIG. A conductive partition wall 21 for blocking the opening of the battery container 1, and this partition wall 2
1. A contact conductor 22 joined to the center of 1 from the inside, and a partition wall 21.
And a cutting blade portion 29 protruding from the outer side with respect to the outer side surface of the. That is, the battery safety device according to the present embodiment is incorporated in a battery having a substantially cylindrical rotationally symmetrical outer shape as a part of the lid 2 forming one pole (usually the positive electrode) of the battery.

First, the structure of the battery will be briefly described. In addition, the upper and lower sides in the description of the embodiments are defined by the upper and lower sides in the reference drawings. This battery has a bottomed cylindrical container 1 having good conductivity and constituting a negative electrode terminal,
The container 1 includes a lid 2 for sealing the upper opening of the container 1, an electrode assembly 3 and an electrolytic solution (not shown) housed in the container 1. The electrode assembly 3 is a separator (see FIG. 2) made of a porous film, which is a round rod-shaped current collector rod 31 on the positive electrode side that is erected along the axis, a sheet-shaped positive electrode (not shown) and a negative electrode (not shown). (Not shown), and a spirally wound electrode portion (not shown) wound in a spiral shape, and is immersed in the electrolytic solution. The collector rod 31 is electrically connected to the positive electrode.

Next, the lid 2 incorporating the safety device of this embodiment will be described. The lid 2 is provided with an outer lid 20 that serves as an external positive electrode terminal, a partition wall 21 that is located inside the outer lid 20 and is stacked vertically, and a partition wall 21 that is located inside the partition wall 21 and stacked vertically. Contact conductor 22 and insulating material 23, 24, 26
And an outer peripheral frame 27 made of a thin plate metal for integrating the above-mentioned members, a breaking blade portion 29, and an insulating material 25.

The outer peripheral frame 27 is formed by molding a thin metal plate having good conductivity, and has an upper wheel plate portion 27a, a cylindrical portion 27b extending axially downward from the outer periphery of the upper wheel plate portion 27a, and a cylinder. Lower wheel plate portion 27 extending radially inward from the lower end of the portion 27b
It consists of c and. The outer peripheral frame member 27 is welded to the inner peripheral surface of the container 1 in the vicinity of the upper end opening of the container 1 at the cylindrical portion 27b, and is welded and hermetically fixed.

The outer lid 20 is made of aluminum alloy or the like and has a thick disk shape. The outer lid 20 has a stepped portion on its outer peripheral portion, so that the central portion thereof projects upward from the outer peripheral portion. The outer lid 20 has a fitting hole into which a breaking blade portion 29, which will be described later, is fitted and inserted, and several (at least one) internal pressure release holes 20a around the outer lid 20.

The partition wall 21 is made of a thin circular plate made of an aluminum alloy and having a thickness of about 0.2 mm. The upper surface of the outer peripheral portion of the partition wall 21 is pressed against the lower surface of the outer peripheral portion of the outer lid 20 to be in close contact therewith. are doing. The contact conductor 22 is a highly rigid, substantially circular disk-shaped conductive member made of an aluminum alloy, and a contact protrusion 22d protruding upward in the axial direction is formed in a central portion 22a thereof. As shown in FIG. 2, the contact protrusion 22d has a shape in which a cone is horizontally cut in the middle, and a horizontal joint plane 22e corresponding to a predetermined joint area is formed on the top of the cone. There is. Further, between the central portion 22a and the outer peripheral portion 22b of the contact conductor 22, a proper number of openings 22c that communicate with each other in the vertical direction are formed. An end of a lead 32 is welded to a part of the lower surface of the contact conductor 22, and the contact conductor 22 is connected to the collector rod 31 through the lead 32.
Is electrically connected to

As shown in FIG. 3, the partition wall 21 and the contact conductor 22 are spot-welded at the joint surface between the lower surface of the partition wall 21 and the joint plane 22e, and both are conductive only in this portion, and other conductive paths are formed. There is no. The outer peripheral portion of each of the outer lid 20, the partition wall 21, and the contact conductor 22 is provided with a cylindrical insulating material 24 with a hollow bottom and an insulating material 23 having a wheel plate shape.
It is clamped by the upper and lower wheel plate portions 27a and 27c of No. 7. The ring-shaped insulating material 26 is attached to the outer peripheral portion of the partition wall 21 and the contact conductor 22.
It is sandwiched between the outer peripheral portion 22b and the outer peripheral portion 22b to electrically isolate and insulate them. Further, the ring-shaped insulating material 25 is used for the outer peripheral frame 27.
The lower wheel plate portion 2c is joined to the lower surface of the lower wheel plate portion 27c.
The lower surface of 7c is electrically insulated.

The breaking blade portion 29 is a member made of a good conductive metal (for example, stainless steel) having a substantially thick disk shape, and is fitted and fixed in a fitting hole in the central portion of the outer lid 20. Of course, the outer lid 20 and the breaking blade portion 29 may be joined by welding or the like, they may be integrally formed, or the breaking blade portion 29 may be joined to the lower surface of the outer lid 20 having no fitting hole in the center. It is possible. The breaking blade portion 29 has a plurality of downward cutting blade protrusions 29 a on the lower surface of the outer peripheral portion thereof, and these serve as blade portions for breaking the partition wall 21. The horizontal cross-sectional shape of the cutting blade projection 29a may be an appropriate shape such as a T-shape, a dogleg shape, a circumferential shape or a semicircular shape, as well as a single-character shape like a cutting knife.

In the battery described above, the blade portion 29 and the outer lid 20 forming the positive electrode of the battery have the partition wall 21 and the contact conductor 2.
2 and a lead 32, which is connected to the positive electrode inside the battery. (Operation of Embodiment 1) The operation of the battery safety device of this embodiment configured as described above when the internal pressure of the battery rises will be described below.

First, when the internal pressure of the battery is within the normal range, the partition wall 21 does not receive a large internal pressure. Therefore, as shown in FIG. 1 again, the partition wall 21 and the contact conductor are welded to each other on the entire welding plane 22e. 22 is in conduction, and the battery has normal conduction. Next, when the internal pressure of the battery rises, as shown in FIG. 4, the plate-shaped partition wall 21 is urged upward by the internal pressure, and this force separates the welded portion between the partition wall 21 and the contact conductor 22. As a result, the partition wall 21 is plastically deformed to be convex upward, and the energization is cut off. When the energization is cut off, the rise in the internal pressure due to a short circuit or overcharge is eliminated, so that the power is cut off and eventually the battery is stopped to prevent the battery from bursting.

Here, the peel strength of the welded portion between the partition wall 21 and the contact conductor 22 is suppressed to less than the breaking strength of the partition wall 21. (On the contrary, the peeling strength of the welded portion depends on the partition wall 21.
When the breaking strength is higher than the breaking strength, the partition wall 21 breaks around the welded portion and a breakage occurs to release the internal pressure, but the conduction is not always interrupted. Therefore, although it is possible to adopt such a configuration, it is not preferable because heat generation and gas generation due to short circuit or overcharge do not stop as long as there is conduction. However, if the internal pressure rises due to overheating, etc., the internal pressure may continue to rise even if the power supply is cut off. When the internal pressure still rises in this way, as shown in FIG. 5, the partition wall 21 expanded and displaced outward (upper side in the figure).
However, it presses itself against the downward cutting blade protrusion 29a of the breaking blade portion 29, and the break B is formed in the partition wall 21. When the partition wall 21 ruptures to generate the rupture B, the internal gas is ejected from there and is further discharged to the outside air through the internal pressure discharge hole 20a of the outer lid 20. In this manner, the partition wall 21 is broken by the breaking blade portion 29 against an abnormal increase in the internal pressure that continues even after the power supply is cut off.
By letting the gas at the internal pressure escape to the outside of the battery, the battery is prevented from bursting.

(Manufacturing Method of Embodiment 1) The lid 2 including the battery safety device of this embodiment described above is manufactured, for example, by the following assembly process (see FIG. 1 again). First, the partition wall 21
The insulating material 26 is sandwiched between the contact conductor 22 and the contact conductor 22, and the central portion of the partition wall 21 and the joint plane 22e of the contact conductor 22 are
Welded by spot welding to form a septum semi-assembly.

Next, the outer lid 2 to which the breaking blade 29 is fixed
0 and the partition wall 21 are overlapped with each other and fitted into the outer peripheral frame body 27 with the insulating materials 23 and 24 interposed therebetween. Here, the inner peripheral edge of the upper wheel plate portion 27a of the outer peripheral frame body 27 is initially opened to the outside (upper side in FIG. 1), so that the partition wall semi-assembly can be fitted easily. After fitting, the upper wheel plate portion 27a is crimped to the regular position shown in FIG. Further, the insulating material 25 is bonded to the outer peripheral frame body 27 in advance.

In this way, the lid 2 is assembled.
One end of a ribbon-shaped lead 32 is connected to the contact conductor 22. The other end of the lead 32 is connected to the positive electrode in advance. After connecting to the contact conductor 22, the lead is folded and the lid 2 is fitted into the container 1, and the lid 2 is welded to the container 1 to complete the assembly. The lead may be omitted by simply bringing the contact conductor 22 and the collector rod 31 into contact with each other to electrically connect them and also electrically connecting the positive electrode and the collector rod 31 to each other. However, the assembly process and the battery structure itself are not the characteristic parts of this embodiment. Therefore, the battery structure may be a laminated structure other than the spiral structure, and various known modifications can be adopted.

(Effect of Embodiment 1) As described in detail above,
The battery safety device of this embodiment has the following three effects. First, when a force is applied to the partition wall 21 due to an increase in the internal pressure, the contact protrusions 2 of the contact conductor 22 before the partition wall 21 is broken.
The welded portion of the 2d joining plane 22e is separated, and the partition wall 2
The conduction between 1 and the contact conductor 22 is cut off. In this way, the welded portion between the partition wall 21 and the contact conductor 22 is limited to the area of the joint plane 22e, so that the joint strength becomes constant and no variation occurs between products.

Therefore, the conduction cutoff pressure is set with extremely high accuracy, and there is an effect that there is no variation between products. Secondly, since the blade portion 29 for breaking that comes into contact with the partition wall 21 displaced by the increase in the internal pressure after the interruption of energization and breaks this is provided, not only depends on the breaking strength of the partition wall 21, but also the accurate internal pressure value is used. The partition wall can be broken.

Therefore, the partition breaking pressure is set with extremely high accuracy, and there is an effect that there is no variation between products. Thirdly, since the partition wall 21 is made of a flat plate and the other members (parts) have a relatively simple shape, the cost of parts is low. The dimensional accuracy is required only for the plate thickness of the partition wall 21 and the area of the joint plane 22e of the contact conductor 22. However, both of them have the same accuracy as that of a normal component, and therefore, particularly precise work is not required. Similarly, manufacturing including assembly and welding is easy, and the number of manufacturing steps is reduced.

Therefore, there is an effect that the manufacturing cost of the product can be reduced. (Modification of First Embodiment) In the first embodiment described above, the partition wall 21 is used.
The peel strength of the welded portion between the contact conductor 22 and the contact conductor 22 is suppressed to be less than the breaking strength of the partition wall 21, and if it is the reverse, there is a possibility that conduction may not be interrupted, which is inconvenient.

Therefore, if the breaking strength of the partition wall 21 is uncertain, the back side (outer side surface) of the partition wall 21 may be reinforced by lining it. The reinforcing material of the lining is formed of a disk made of the same material as the partition wall 21, and is firmly fixed to the center portion of the partition wall 21 by welding. The diameter of the disk is larger than the diameter of the joining plane surface 22 and is suppressed so as not to interfere with the cutting of the breaking blade portion 29.

In this way, it does not hinder the expansion and displacement of the partition 21 to the outside, and the breaking strength of the partition 21 can be reinforced. As a result, the welded portion of the partition wall 21 is joined to the joint plane 22.
When peeling from e, there is no fear that the partition wall 21 will be broken. [Embodiment 2: The partition wall is in contact with the contact conductor by the elastic force of the spring and is equipped with the electrolytic solution absorber] In the above-described Embodiment 1, once the welding between the partition wall 21 and the contact conductor 22 is separated, a short circuit occurs.
Even if the cause of the internal pressure rise such as overcharging or overheating was eliminated, the conduction did not recover again. Further, when the partition wall 21 is ruptured due to the further increase in internal pressure, the battery contents such as the electrolytic solution may leak and damage the peripheral devices.

Therefore, as an example of the battery safety device of the present invention in which these points are taken into consideration, Example 2 will be illustrated below. As shown in FIG. 6, the battery safety device of the present embodiment has almost the same configuration as that of the first embodiment, and is different only in the following two points. (Joining of the contact conductor of Example 2 and its partition wall) That is, the first difference is that the contact protrusion 22 of the contact conductor 22 'is formed.
d ′ is formed so as to project higher than the first embodiment by a predetermined dimension. Also, the joining plane 2 at the tip
A conductor layer (not shown) of gold foil is formed on 2e. Further, unlike the first embodiment, the contact conductor 22 ′ is not welded to the partition wall 21 and the partition wall 21e is formed at the joint plane 22e.
Just abut.

When the contact conductor 22 'and the partition wall 21 are assembled as a safety device, as shown in FIG. 6, the partition wall 21 is pushed up at the center by the contact protrusion 22d' and elastically deforms upward. . As a result, the spring elasticity of the partition wall 21 urges the contact conductor 22 'and the partition wall 21 into contact with each other with a pressing force sandwiching the conductor layer of the gold foil. Kindoma is excellent in oxidation resistance and corrosion resistance, and is excellent in electric conductivity, soft and easy to be familiar, so that the conduction between the contact conductor 22 ′ and the partition wall 21 is surely maintained.

The above is the case where the internal pressure is equal to or lower than the predetermined value (conduction breaking pressure). When the battery internal pressure exceeds a predetermined value, the partition wall 21 elastically deforms and slightly separates from the joint plane 22e, and the electrical connection between the contact conductor 22 'and the partition wall 21 is cut off. Therefore, if the internal pressure rises due to a short circuit or overcharge of the circuit, it is possible to prevent further troubles due to the interruption of conduction.

Here, the conduction breaking pressure of a predetermined value can be adjusted by the height of the contact protrusion 22d '. Further, since the continuity is maintained by the spring elastic force of the partition wall 21, the pressure for separating the contact, that is, the conduction breaking pressure can be set more precisely than in the first embodiment in which the contact was maintained by the welding force. Therefore, there is an effect that it is possible to further reduce the variation in the conduction cutoff pressure between products.

Further, since conduction is obtained not by welding but by contact by spring elastic force, there is a characteristic that even if the conduction pressure is once exceeded and the conduction is interrupted, the conduction can be resumed if the internal pressure decreases. is there. Therefore, if the cause of the internal pressure rise such as short circuit, overcharge or overheat is eliminated, it is difficult to exert sufficient battery performance, but there is an effect that it can be used for the time being. If no spare battery is prepared, this effect will greatly benefit the user.

When the internal pressure rises above the partition rupture pressure and the partition 21 is deformed until a rupture occurs, the partition 21 has already entered the plastic deformation region, and therefore the conduction is not restored again. (When gas is generated until the internal pressure rises so much, the battery has already lost its function,
Normally, even after the cause of the increase in internal pressure is removed, a normal battery action cannot be expected. (Second Embodiment Electrolytic Solution Absorber) The second difference is that the battery safety device of the present embodiment has the electrolytic solution absorber 28 outside the partition wall 21 inside the lid 2.

That is, a washer-shaped (hollow disk-shaped) absorber 28 made of a sponge material is adhered to the back surface of the outer lid 20. The absorber 28 covers and closes the inside of the internal pressure discharge hole 20a, but since the material of the absorber 28 is porous and has air permeability, the function of the internal pressure discharge hole 20a is not impaired. In the present embodiment as well, similarly to the first embodiment, when the internal pressure rises abnormally to reach the partition wall breaking pressure, the partition wall 21 is ruptured.
Even if a liquid such as an electrolytic solution, a solid matter, a powder, or the like should be ejected from the breakage of the partition wall 21, the absorber 28 prevents the absorber 28 from absorbing or filtering them and leaking them. . As a result, only the gas that has generated the internal pressure is discharged from the internal pressure discharge hole 20a, and other liquids or solids do not leak to the outside of the battery, and there is no concern that the surroundings of the battery may be polluted and the device may malfunction. Absent.

If the gas generated inside the battery is toxic, there is also a means for charging the absorbent 28 with an absorbent such as activated carbon so that the absorbent does not leak outside. (Effect of Embodiment 2) As described in detail above, according to the battery safety device of Embodiment 2, in addition to the effect of Embodiment 1,
There are effects such that the conduction cutoff pressure can be precisely set, regeneration is possible after the conduction cutoff, and the electrolytic solution is not leaked.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a battery safety device according to a first embodiment.

FIG. 2 is a perspective view showing the shape of a contact conductor according to the first embodiment.

FIG. 3 is a partial cross-sectional view showing a joined state of the contact conductor and the partition wall according to the first embodiment.

FIG. 4 is a cross-sectional view showing a power-off state of the battery safety device according to the first embodiment.

FIG. 5 is a cross-sectional view showing a damaged state of the partition wall of the battery safety device according to the first embodiment.

FIG. 6 is a cross-sectional view showing a configuration of a battery safety device according to a second embodiment.

[Explanation of symbols]

1: Container 2: Lid 20: Outer Lid 20a: Internal Pressure Discharge Hole 21: Partition Wall 22, 22 ': Contact Conductor 22a: Central Part 22
b: outer peripheral portion 22c: opening 22d, 22d ': contact protrusion 22
e: Joining plane 23, 24, 25, 26: Insulating material 27: Peripheral frame 28: Electrolyte solution absorber 29: Breaking blade 29a:
Cutting edge protrusion

Claims (7)

[Claims] 1. A conductive partition wall which shields an opening of a container for containing a battery electrode and an electrolytic solution, and a conductive partition wall located inside a central portion of the partition wall and fixed to the container and capable of conducting to the electrode. A battery safety device comprising a conductive contact conductor to be connected, wherein interruption of conduction between the partition wall and the contact conductor and breakage of the partition wall occur due to displacement of the partition wall due to increase in internal pressure of the container, The safety device for a battery, wherein the contact conductor has a contact protrusion that projects toward the inner surface of the partition wall and comes into contact with the wall surface to conduct electricity. 2. At least one breaking blade portion fixed directly or indirectly to the container and facing the central portion of the outer surface of the partition wall with a predetermined gap therebetween. The battery safety device according to claim 1. 3. The battery safety device according to claim 1, wherein the contact protrusion has a joining plane formed on the top of the contact protrusion in parallel with the inner surface of the partition wall. 4. The contact conductor and the partition wall are joined together at the top of the contact protrusion by any one of welding, brazing, soldering, welding, and fusion welding. The battery safety device according to any one of 1 to 3. 5. The battery safety according to claim 1, wherein the contact conductor and the partition wall are biased by a spring elastic force of the partition wall and are in contact with each other with a pressing force. apparatus. 6. A conductor layer having excellent electrical conductivity, oxidation resistance and corrosion resistance is formed on at least one surface of the top of the contact protrusion and the contact portion inside the partition wall with which the top contacts. The battery safety device according to claim 5, which is provided. 7. The electrolytic solution absorber, which is directly or indirectly held in the container, is provided outside the partition wall.
The battery safety device according to any one of to 6.