JP5289164B2 - Surface spring and safety valve using the same - Google Patents

Description

  The present invention relates to a planar spring and a safety valve using the same, and includes a secondary battery such as a lithium secondary battery and a nickel hydride secondary battery, a capacitor such as an aluminum electrolytic capacitor and an electric double layer capacitor, and an electric quantity memory. The present invention relates to an element used for an electrochemical element such as a sensor, and in particular, only a by-product gas out of various gases generated in the container during the normal use of the electrochemical element, the container internal pressure exceeds the set pressure. The present invention relates to a planar spring used for instantly dissipating electrolyte solution outside the container while leaving the electrolyte in the container, and a self-returning type safety valve using the same.

  Conventionally, explosion-proof safety valves have been mainly used for secondary batteries and capacitors. As shown in FIG. 9 of Patent Document 7, in the case of an aluminum electrolytic capacitor or an electric double layer capacitor, the structure of a typical explosion-proof safety valve is that a bottom step 123 of an aluminum metal case 121 is subjected to a cross stepping process 124 and the like. The case thickness is made thinner than this part, and when the safety limit is reached, the stepped portion is destroyed.

  As conventional explosion-proof safety devices for batteries, for example, one using a stainless steel plate (see Patent Document 1) and one using a nickel foil plate (see Patent Document 2) are disclosed. In the large stationary sealed lead-acid battery described in Patent Document 2, a catalyst plug is used to prevent corrosion due to acid fog in the periphery of the battery, and hydrogen gas and oxygen gas generated during charging and discharging are converted into water using a catalyst. To prevent the gas pressure inside the battery from rising.

  In addition, a structure using a porous membrane having open cells produced by stretching a fluororesin (PTFE) film is disclosed (see Patent Document 3).

  Further, a structure having a self-returning pressure adjusting function is disclosed (Patent Document 4, Patent Document 5, Patent Document 6, and Patent Document 7). In FIG. 1 of Patent Document 6, a ball valve 20 and a ball valve 21 are pressed and urged toward the gas inlet 10A in a valve chamber 10B (gas passage portion) having a gas inlet 10A (gas diffusion port). A structure provided with a spring body 21 is disclosed. Further, FIG. 8 of Patent Document 7 shows that the internal pressure of the battery container is damaged at a predetermined pressure and degassed for the purpose of preventing an accident caused by the explosion of the battery when it is abnormally high due to heating or overcurrent. A structure for performing is also disclosed.

JP 59-79965 A JP-A-10-172529 JP-A-5-159765 JP-A-8-259854 Japanese Patent Laid-Open No. 11-14015 JP 11-339746 A JP 2004-221129 A

  However, the method of providing the stepped portion on the aluminum metal case described above is low in cost, but it is considered that the pressure at the time of breakage varies greatly and the reliability is poor.

  In the safety valve using the metal foil strip according to Patent Document 1, explosion is prevented when the safety valve is operated, but electrochemical elements such as batteries and capacitors are euthanized and cannot be used thereafter.

  Moreover, although the catalyst plug according to Patent Document 2 is safe, it is expensive and large in shape, and requires more volume than a small battery with only the catalyst plug. Therefore, it cannot be applied to a small electrochemical device.

Furthermore, the fluororesin porous film according to Patent Document 3 has problems in terms of mechanical strength, reliability, and yield, and not only gas but also electrolyte is ejected simultaneously when gas escapes during normal use. Had a problem to do. In addition, this structure has many problems in practical use, such as difficulty in homogenizing the porosity, liquid loss, poor yield, and incomplete H ₂ O impermeability.

In the structures described in Patent Documents 4 to 7, the coil spring has a large aspect ratio, is difficult to reduce in size, and requires a relatively large space for mounting. Also compared to 15~20kgf / cm ² about a coil spring for high pressure, in the case of a coil spring for low pressure of about 3~10kgf / cm ² has poor spring precision, it is difficult to lower pressure drive. For this reason, a self-recovery type safety valve that is small, can operate at a low pressure of ^{2 to 5} kgf / cm ² , and has a fast response speed has not been put into practical use for an aluminum can body such as an electric double layer capacitor. Is the current situation.

  The safety valve described in Patent Document 7 is a gas permeable safety valve, but the gas permeation amount of the gas permeable safety valve film is small, so that it can be applied to a large electrochemical element (large electric double layer capacitor). Remains a challenge.

  Further, in recent years, as electronic devices such as mobile phones, personal computers, and PDAs are miniaturized, these electrochemical elements have been miniaturized. In addition, the heat resistance characteristics during solder reflow during manufacturing and the environmental conditions for use of portable devices are becoming stricter, and the gas generation problem of electrochemical elements used for these is becoming more serious.

  In addition, with the commercialization of HEV vehicles (hybrid cars), HEV vehicles are used in cold regions, and large-capacity electric double layer capacitors that are used in combination with nickel metal hydride batteries are in practical use as a countermeasure for low temperatures in HEV vehicles. It has become. For these electrochemical elements, a temperature cycle test of +60 to −30 ° C. is required, and countermeasures against gas generation are urgently needed.

  In addition, in FY2007, Toyota Motor Corporation and Daihatsu Kogyo Co., Ltd. have put into practical use electric double layer capacitors for engines and catalyst assist from the application of Brake by wire. In addition, Ricoh Co., Ltd. has put a large electric double layer capacitor into practical use for a commercial high-speed copier. For such large-sized and high-current applications, a large aluminum can is used for the can body, so it is expected to be lighter and more compact, low-pressure drive, small aspect ratio, compact, and instantaneous gas dissipation There is an urgent need to develop a self-recoverable safety valve.

  In consideration of the above facts, the present invention is extremely reliable and can be operated at a low pressure. Among various gases generated in the container during normal use, only the by-product gas is used, and the internal pressure of the container exceeds the set pressure. A safety valve that can instantaneously dissipate out of the container and can self-recover after gas dissipation, and can be applied to ultra-small to large-sized electrochemical devices, and a surface shape used for the safety valve The object is to provide a spring.

The invention according to claim 1 (planar spring) includes a base portion formed in a planar shape and a frame shape, and a load receiving portion that is elastically supported via a plurality of spring element portions on the inner side in the surface direction of the base portion. A rupture portion that is provided at at least one of the base, the spring element portion, and the load receiving portion, and that ruptures when a load of a predetermined level or more is applied to the load receiving portion. Yes.

  In the planar spring according to claim 1, a base portion formed in a planar shape and a frame shape, and a load receiving portion elastically supported via a plurality of spring element portions on the inner side in the surface direction of the base portion. Since it has an integrated structure, when a load is input to the load receiving part, the load receiving part is instantaneously and elastically displaced with respect to the base part, and when the load disappears, the original state is restored. To do.

  Therefore, by applying this planar spring to a safety valve, it is extremely reliable and can be operated at low pressure. Among various gases generated in the target container during normal use, only the by-product gas is set as the container internal pressure. When the pressure exceeds the pressure, the gas evacuation port is opened to dissipate instantaneously outside the container, and the gas evacuation port can be closed by self-return after gas evacuation. A safety valve that can also be applied to chemical elements can be obtained.

In addition , when a predetermined load or more is applied to the load receiving portion, a rupture portion provided in at least one of the base portion, the spring element portion, and the load receiving portion is ruptured. Therefore, by applying this planar spring to the safety valve, when an excessive pressure is generated in the target container, the pressure can be instantaneously dissipated.

According to a second aspect of the invention, the planar spring according to claim 1, the outer dimensions of the base and X, displacement of the load receiving portion at one thickness direction of the base portion by elastic deformation of the spring element unit If the possible dimension is Y, the aspect ratio (Y / X) is 0.1 to 0.5.

In the planar spring according to claim 2, when the outer dimension of the base is X and the displaceable dimension of the load receiving part in one of the bases in the thickness direction due to elastic deformation of the spring element part is Y, the aspect ratio (Y Since / X) is 0.1 to 0.5, the response accuracy of the displacement of the load receiving portion at the time of load input can be increased while downsizing the planar spring.

According to a third aspect of the present invention, in the planar spring according to the first or second aspect, the planar spring includes a Ni electroformed metal, a Ni-based alloy electroformed alloy, a Cu electroformed metal, a Cu-based spring. An electroformed alloy of an alloy, or a Pd—Ni alloy, a Pd—Co alloy, or a Pd—Ni—Co ternary alloy, which is made of an electroformed alloy containing 10 to 90% of Pd.

The planar spring according to claim 3 , wherein the planar spring is an electroformed metal of Ni, an electroformed alloy of an Ni-based alloy, an electroformed metal of Cu, an electroformed alloy of a Cu-based alloy, or a Pd-Ni alloy, Since it is made of a Pd—Co alloy or a Pd / Ni / Co ternary alloy and containing 10 to 90% of Pd, the spring characteristics, corrosion resistance, and reliability can be improved.

According to a fourth aspect of the present invention, in the planar spring according to any one of the first to third aspects, the thickness of the planar spring is 1 to 100 μm.

In the safety valve according to the fourth aspect, since the thickness of the planar spring is 1 to 100 μm, the manufacturing cost can be suppressed while ensuring the mechanical strength.

An invention (safety valve) according to claim 5 includes the planar spring according to any one of claims 1 to 4 and a valve body that is pressed and urged by the planar spring to the gas diffusion hole. Have.

According to a fifth aspect of the present invention , the safety valve includes the planar spring according to any one of the first to fourth aspects, and a valve body that is pressed and urged to the gas diffusion hole by the planar spring. Therefore, pressure regulation during normal use of the container to which the safety valve is attached can be performed by appropriately elastically deforming the planar spring. In a planar spring having a rupture portion, when a load exceeding a predetermined value is applied to the load receiving member of the planar spring, the rupture portion may rupture, thereby dissipating the pressure in the container. it can.

The invention of claim 6 (electrochemical element) has the safety valve of claim 5 .

The electrochemical element according to claim 6 has the safety valve according to claim 5 , so that only by-product gas out of various gases generated in the container of the electrochemical element during normal use is stored in the container. When the internal pressure exceeds the set pressure, it can be instantaneously dissipated out of the container. When a planar spring having a rupture portion is used for the safety valve, when an excessive pressure is generated in the container, the rupture portion may be ruptured to dissipate the pressure instantly. it can. For this reason, the reliability and safety | security of an electrochemical element can be improved.

  As described above, according to the planar spring of the first aspect of the present invention, it is extremely reliable, can be operated at a low pressure, and is a by-product of various gases generated in the container during normal use. It is possible to obtain a safety valve that can instantaneously dissipate only gas when the internal pressure of the container exceeds the set pressure, and that can be applied to ultra small to large electrochemical devices. The excellent effect of being able to be obtained is obtained.

According to the planar spring of the second aspect, it is possible to obtain an excellent effect that the response accuracy of the displacement of the load receiving portion at the time of load input can be increased while the planar spring is downsized.

According to the planar spring of the third aspect, it is possible to obtain an excellent effect that the spring characteristics, corrosion resistance, and reliability can be improved.

According to the safety valve of the fourth aspect , it is possible to obtain an excellent effect that the manufacturing cost can be suppressed while ensuring the mechanical strength.

According to the safety valve of Claim 5 , the outstanding effect that the pressure regulation at the time of normal use of the container with which the safety valve was attached can be performed.

According to the electrochemical element of the sixth aspect , it is possible to obtain an excellent effect that the durability and safety of the electrochemical element can be improved.

1 and 2 relate to a first configuration example of a planar spring, and FIG. 1 is a front view showing the planar spring. It is a side view which shows the amount of displacement of a load receiving part with respect to the external dimension of a planar spring. It is a front view which shows the planar spring which concerns on a 2nd structural example. It is a front view which shows the planar spring which concerns on a 3rd structural example. It is a front view which shows the planar spring which concerns on a 4th structural example. It is a principal part enlarged view which shows the structure of a rupture part. It is a front view which shows the planar spring which concerns on a 5th structural example. It is a principal part enlarged view which shows the structure of a rupture part. It is a front view which shows the planar spring which concerns on a 6th structural example. It is a principal part enlarged view which shows the structure of a rupture part. It is a front view which shows the planar spring which concerns on a 7th structural example. It is a front view which shows the planar spring which concerns on the 8th structural example. It is a front view which shows the planar spring which concerns on the 9th structural example. It is a front view which shows the planar spring which concerns on a 10th structural example. It is a front view which shows the planar spring which concerns on the 11th structural example. It is a diagram which shows the relationship between the thickness of a planar spring, and a response working pressure. It is a front view which shows the planar spring which concerns on the 12th structural example. It is a front view which shows the planar spring which concerns on the 13th structural example. It is a front view which shows the planar spring which concerns on the 14th structural example. It is a front view which shows the planar spring which concerns on the 15th structural example. It is a front view which shows the planar spring which concerns on the 16th structural example. It is the diagram and table | surface which show the relationship between the stress and distortion of various electroformed metals. It is a schematic diagram which shows the pattern and electroformed metal which were controlled by the resist in photoelectroforming. It is an expansion perspective view which shows the width dimension and thickness dimension of the spring element part manufactured by electroforming. It is sectional drawing which shows the safety valve attached to the valve seat of the can of an electrochemical element. It is an expanded sectional view showing a disc spring.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Surface spring]
(First configuration example)
In FIG. 1, the planar spring 1 according to the first configuration example integrally includes a base portion 20 and a load receiving portion 22.

  The base portion 20 is formed in a planar shape and a frame shape, for example, an annular shape and a planar shape. The outer shape of the base 20 is not limited to a circle, but may be a polygon or an ellipse.

  The load receiving portion 22 is elastically supported via a plurality of spring element portions 26 on the inner side in the surface direction of the base portion 20. Specifically, the load receiving part 22 is located in the center part of the base 20, for example. A through hole 22A is formed in the center of the load receiving portion 22 so that a valve body 42 (FIG. 25) of a safety valve 40 (to be described later) is fitted. Thereby, the load receiving part 22 has an annular shape. In the planar spring 1, a region that is not any of the base portion 20, the load receiving portion 22, and the spring element portion 26 is a hole portion 30.

  The spring element portions 26 extend in the radial direction of the base portion 20 so as to connect the outer peripheral edge of the load receiving portion 22 and the inner peripheral edge of the base portion 20, and are arranged at six locations in the circumferential direction of the base portion 20. In other words, the spring element portions 26 are evenly arranged at intervals of 60 °. Each spring element portion 26 is formed in a sine wave shape having an amplitude in a surface direction of the base portion 20 and a direction orthogonal to the radial direction of the base portion 20, for example.

  At least one portion of the base 20, the spring element portion 26, and the load receiving portion 22 is provided with a rupture portion 28 that ruptures when a load of a predetermined level or more is applied to the load receiving portion 22. In the first configuration example, for example, a rupture portion 28 is provided in the load receiving portion 22. The rupture portion 28 is configured as a constricted portion that is locally narrowed, and is formed at, for example, two locations in the circumferential direction of the load receiving portion 22. Note that the structure of the rupture portion 28 is appropriately changed according to the pressure of the applied product (electrochemical element or the like) and the rupture response speed as in a second configuration example to a sixteenth configuration example described later.

  As shown in FIG. 2, in the planar spring 1, the outer dimension (outer diameter) of the base portion 20 is X, and the displacement of the load receiving portion 22 on one side in the thickness direction of the base portion 20 due to elastic deformation of the spring element portion 26. When the possible dimension is Y, the aspect ratio (Y / X) is 0.1 to 0.5. Here, the reason why the lower limit value of the aspect ratio is set to 0.1 is that if it is less than this value, the response accuracy when the load receiving portion 22 is displaced at the time of the load receiving portion 22 becomes poor. Moreover, the reason why the upper limit of the aspect ratio is set to 0.5 is that when this value is exceeded, the shape of the planar spring 1 becomes large. Therefore, by setting the aspect ratio in this way, it is possible to increase the response accuracy of the displacement of the load receiving portion 22 at the time of load input while downsizing the planar spring 1. In FIG. 2, the displacement direction of the load receiving portion 22 is above the thickness direction of the base portion 20, but can be similarly displaced downward.

  The thickness Z of the planar spring 1 is 1 to 100 μm. Here, the reason why the lower limit value of the thickness Z is set to 1 μm is that if it is less than this value, it becomes difficult to ensure the mechanical strength of the planar spring 1. The reason why the upper limit value is set to 100 μm is that when this value is exceeded, the manufacturing cost of the planar spring 1 increases. Therefore, by setting the thickness Z of the planar spring 1 in this way, the manufacturing cost can be suppressed while ensuring the mechanical strength of the planar spring 1. The validity of the thickness Z range will be described again in an eleventh configuration example described later.

  In consideration of securing spring characteristics, corrosion resistance and reliability, the planar spring 1 is, for example, an electroformed metal of Ni, an electroformed alloy of a Ni-based alloy, an electroformed metal of Cu, an electroformed alloy of a Cu-based alloy, or A Pd—Ni alloy, a Pd—Co alloy, or a Pd / Ni / Co ternary alloy, which is made of an electroformed alloy containing 10 to 90% of Pd. In addition to this, it is also possible to add magnetic elements such as Mo, Nb, Fe, and Mn. The manufacturing method of the planar spring 1 will be described in detail later. Note that the material of the planar spring 1 is not limited to metal, and any material may be used as long as it has a spring property. For example, it may be a polymer material having spring properties or ceramics.

(Second configuration example)
In FIG. 3, in the planar spring 2 according to the second configuration example, the rupture portions 28 are formed at six locations in the circumferential direction of the load receiving portion 22. The spring element portions 26 are also arranged at six locations in the circumferential direction of the base portion 20, and rupture portions 28 are formed between the adjacent spring element portions 26. Since other parts are the same as those in the first configuration example, the same parts are denoted by the same reference numerals in the drawings, and the description thereof is omitted.

(Third configuration example)
In FIG. 4, in the planar spring 3 according to the third configuration example, a notch 22 </ b> B opened to the outer periphery of the load receiving portion 22, for example, between the adjacent spring element portions 26 is 6 in the circumferential direction of the load receiving portion 22. It is formed in the place. The spring element portions 26 are also arranged at six locations in the circumferential direction of the base portion 20, and notches 22B are formed between the adjacent spring element portions 26, respectively. The notch 22 </ b> B is partially wider in the circumferential direction of the load receiving portion 22, and the constricted portion formed in the load receiving portion 22 thereby becomes a rupture portion 28. Other parts are the same as those in the first configuration example.

(Fourth configuration example)
In FIG. 5, in the planar spring 4 according to the fourth configuration example, a through hole 22 </ b> A is provided in the center of the load receiving portion 22, and a notch 22 </ b> B that opens to the outer periphery of the load receiving portion 22 includes the load receiving portion 22. It is formed on both sides of the spring element portion 26 in the circumferential direction of the portion 22. As shown in FIG. 6, a pair of the notches 22 </ b> B is formed on both sides of the spring element portion 26 in the circumferential direction of the load receiving portion 22, and extends so as to approach each other toward the center side of the load receiving portion 22. Terminated. As a result, the constricted portion formed in the load receiving portion 22 is a rupture portion 28. Other parts are the same as those in the first configuration example.

(Fifth configuration example)
In FIG. 7, in the planar spring 5 according to the fifth configuration example, notches 20 </ b> B that open to the inner periphery of the base portion 20 are formed on both sides of the spring element portion 26 in the circumferential direction of the base portion 20. As shown in FIG. 8, a pair of notches 20B are formed on both sides of the spring element portion 26 in the circumferential direction of the base portion 20, and extend so as to approach each other toward the radially outer side of the base portion 20 and terminate. ing. As a result, the constricted portion formed in the base portion 20 is a rupture portion 28. Other parts are the same as those in the first configuration example.

(Sixth configuration example)
9 and 10, in the planar spring 6 according to the sixth configuration example, the rupture portion 28 is provided in the spring element portion 26. The rupture portion 28 is formed in a notch shape, for example, on the outer peripheral side of the curved portion in the sinusoidal spring element portion 26. Other parts are the same as those in the first configuration example.

(Seventh configuration example)
In FIG. 11, in the planar spring 7 according to the seventh configuration example, the spring element portion 26 has a circumferential portion 26 </ b> A that is concentric around the center portion of the load receiving portion 22, the load receiving portion 22, and each circumferential direction. The base portion 20 is configured to have a radial portion 26 </ b> B that extends in the radial direction of the base portion 20 and is arranged at eight locations in the circumferential direction of the base portion 20 so as to connect the portion 26 </ b> A and the base portion 20. Each radial direction part 26B is arrange | positioned equally at 45 degree intervals. Other parts are the same as those in the first configuration example.

(Eighth configuration example)
As shown in FIG. 12, the planar spring 8 according to the eighth configuration example is different from the planar spring 7 according to the seventh configuration example in that the radial direction portion 26 </ b> B in the spring element portion 26 is changed to 4 in the circumferential direction of the base portion 20. It is arranged at the place. The radial direction portions 26B are evenly arranged at 45 ° intervals. Other parts are the same as in the seventh configuration example.

(Ninth configuration example)
As shown in FIG. 13, in the planar spring 9 according to the ninth configuration example, in the planar spring 8 according to the eighth configuration example, the circumferential phase of the concentric hole portion 30 is one in the radial direction. Every other 45 °. Accordingly, the radial direction part 26 </ b> B is intermittently arranged in the radial direction of the base part 20.

(10th configuration example)
In FIG. 14, in the planar spring 10 according to the tenth configuration example, the spring element portion 26 is configured by alternately forming the radial direction portion 26 </ b> B and the circumferential direction portion 26 </ b> A. The spring element portions 26 are provided at four locations in the circumferential direction of the base portion 20. By configuring the spring element portion 26 in this manner, the length of the spring element portion 26 is ensured more, the sensitivity to the load input to the load receiving portion 22 is increased, and the thickness of the base portion 20 is increased. The displaceable dimension Y (FIG. 2) of the load receiving portion 22 can be set larger. Other parts are the same as those in the first configuration example.

(Eleventh configuration example)
As shown in FIG. 15, the planar spring 11 according to the eleventh configuration example is the planar spring 10 according to the tenth configuration example, in which the spring element portions 26 are provided at eight locations in the circumferential direction of the base portion 20. It is.

  Here, an alloy having Ni of 40% and Pd of 60% is used as a material, and a planar spring 11 having the dimensions shown in FIG. 15 is manufactured by electroforming. Since the test was conducted on the relationship, the results will be described. The test results are as shown in Table 1 and FIG. According to this test, it can be seen that by setting the thickness of the planar spring 11 in the range of 1 to 100 μm, the relationship between the thickness and the response operating pressure becomes linear, and excellent spring characteristics can be obtained.

(Twelfth configuration example)
In FIG. 17, in the planar spring 12 according to the twelfth configuration example, the spring element portions 26 alternately form the radial direction portions 26 </ b> B and the circumferential direction portions 26 </ b> A and are adjacent to each other in the radial direction of the base portion 20. An annular portion 26C connected to the radial direction portion 26B is formed between 26A. The spring element portion 26 is provided at eight locations in the circumferential direction of the base portion 20. Other parts are the same as those in the first configuration example.

(13th configuration example)
18, in the planar spring 13 according to the thirteenth configuration example, each spring element portion 26 is formed in a trapezoidal polygonal line shape. Two sets of the spring element portions 26 form one set, and eight sets are provided in the circumferential direction of the base portion 20. The pair of spring element portions 26 are substantially line symmetric with respect to the radial direction of the base portion 20 as a central axis. Other parts are the same as those in the first configuration example.

(14th configuration example)
As shown in FIG. 19, the planar spring 14 according to the first configuration example is obtained by providing ten sets of spring element portions 26 in the circumferential direction of the base portion 20 in the planar spring 13 according to the thirteenth configuration example. .

(15th configuration example)
In FIG. 20, in the planar spring 15 according to the configuration example, each spring element portion 26 is formed in a polygonal line shape having a circumferential direction portion 26A and a radial direction portion 26B. Two sets of the spring element portions 26 form one set, and eight sets are provided in the circumferential direction of the base portion 20. The pair of spring element portions 26 are substantially line symmetric with respect to the radial direction of the base portion 20 as a central axis. A substantially cross-shaped hole 30 is formed between the pair of spring element portions 26. A substantially H-shaped hole 30 is formed between two adjacent sets of spring element portions 26. Other parts are the same as those in the first configuration example.

(16th configuration example)
As shown in FIG. 21, the planar spring 16 according to the first configuration example is the planar spring 1 according to the first configuration example, and sinusoidal spring element portions 26 are provided at 18 locations in the circumferential direction of the base portion 20. It has been. Except for the point that the through hole 22A is not formed in the load receiving portion 22, the other configuration is the same as that of the first configuration example.

(Other configuration examples)
The configuration of the planar spring is not limited to the above-described first configuration example to the sixteenth configuration example, and the configuration can be appropriately changed according to the application and use conditions.

  In the seventh configuration example to the sixteenth configuration example, the load receiving portion 22 may be provided with a shape corresponding to the through hole 22A in the first configuration example. It is also possible to appropriately combine the rupture portions 28 according to the first configuration example to the sixth configuration example with the seventh configuration example to the sixteenth configuration example.

  In each of the above configuration examples, the shape of the planar spring is a planar shape, but is not limited thereto, and may include an uneven surface, an arc surface, or the like. In particular, as in the seventh to sixteenth configuration examples, when the through hole 22A is not provided in the load receiving portion 22, a concave surface corresponding to a valve body 42 (FIG. 25) described later may be provided. Moreover, it is good also as a structure which does not provide the rupture part 28. FIG.

[Manufacturing method of planar spring]
The manufacturing method of the planar springs 1-16 which concern on this embodiment is described. In this embodiment, as a method for producing a planar spring, it is easily considered to punch a planar spring sheet with a mold, but for an electrochemical element that requires precise operation at a low pressure, a spring material by rolling is not suitable. Accuracy cannot be obtained. In this embodiment, it produces by an electroforming method.

The most important part of this embodiment is a planar spring, and the required elements of this part are three-dimensionally small and have to fully exhibit mechanical functions. Therefore, specifically, stability of mechanical properties, high accuracy of shape and dimensions, and chemical stability such as corrosion resistance are required. A conventional coil spring of about 15 to 20 kgf / cm ² is not suitable for a spring that is particularly small in pressure and finely controlled due to the stability of the strength of the spring and variations in the accuracy of the thickness of the coil spring. It is. In such a background, there is a demand for a spring that senses and reacts to a very delicate pressure, particularly a small and quick and accurate response to a minute pressure of about 3 to 10 kgf / cm ² .

  A conventional structure like a coil spring cannot be reduced in size, and is incapable of physical properties, such as being inferior in functions such as transmitting minute strength with delicate motion. As a method for solving this problem, it is most suitable to manufacture a planar spring by electroforming. The electroforming technique is a technique for depositing a metal material by electrolysis, and the thickness of the material can be accurately controlled by electrolysis time. Therefore, the electroforming technique is a technique that allows various types of thicknesses to be manufactured easily and in large quantities. The types of metal materials manufactured by electroforming technology are almost all applicable to metals that can be electrolyzed other than chromium due to stress problems, and there are many types including metal alloys and amorphous metals.

  The characteristics of electroformed metal also have beneficial properties different from general metal materials. In general metal materials, since they are manufactured by melting and rolling processes, there are generally impurities and gas entrainment at the grain boundaries. For this reason, strictly speaking, the materials made from rolled materials vary in physical properties, and these are used as spring materials. Especially for small springs and other functions that detect minute and subtle forces. It is unsuitable. This is particularly a problem with small coil spring components.

  On the other hand, a metal material by electroforming is different from a general metal material, and there are no impurities or gas pits between metal particles. If necessary, alloys and amorphous metals can be easily produced by electroforming as described above. In each case, the electrocast metal is selected in consideration of the physical properties of the material, and the physical and chemical properties of the same metal can be controlled.

  An example is shown in FIG. This graph shows that mechanical properties can be changed by electrolysis conditions, alloy composition, and organic additives in the electrolyte. And it has been confirmed that this property is stable. As described above, the reliability of the electroformed material is extremely high, and a material having optimum physical properties as a spring material can be selected. In particular, the palladium nickel (Ni—Pd) alloy, the palladium cobalt (Pd—Co) alloy, the palladium nickel cobalt (Pd—Ni—Co) ternary alloy and the like listed here are the most desirable materials for the microspring. In particular, it is an optimal metal material for the material as the planar spring of this embodiment and for miniaturization in production.

  In order to make the shape of the spring that operates delicately, the metal material must be formed into, for example, a planar spring shape according to the present embodiment. For this purpose, photolithography is generally used. As this method, a method known as so-called photoelectroforming in which electroforming technology and photolithography are combined is used. As shown in FIG. 23, patterning for preventing electrodeposition with a photoresist 34 is performed in advance on a planar conductor substrate 32 to be electrodeposited by an electroforming method, and then a desired metal 36 is formed by electroforming. A surface with the required shape and springiness as in the various configuration examples described above, using a metal material with the required thickness by electrodeposition and peeling when it reaches the required thickness. A shaped spring can be obtained. The size and shape produced by photoelectroforming does not spread to the side if the thickness of the photoresist 34 is sufficient, and there is no side etching phenomenon that occurs when it is manufactured by an etching method compared with the electroforming method. Therefore, it is possible to maintain extremely accurate dimensions. Of course, the shape of the planar spring according to the present embodiment can be achieved by machining such as pressing, but in that case, it is necessary to take care not to affect the spring characteristics and physical properties due to processing stress due to pressing.

  The performance of a sheet spring made of this photoelectroforming is determined by the mechanical properties of the sheet spring by the selection of the electroformed metal material, and the planar shape and material thickness of the sheet spring are substantially different. For example, it controls the performance and function represented by the strength of the spring element portion 26 in FIG. A spring-shaped cross-sectional area and the like are finally designed and determined. The strength of the planar spring of this embodiment is that the planar spring needs to be a delicately controlled spring, so that it is important that the above manufacturing process can be easily controlled, and photoelectroforming is an optimal manufacturing method. It is a technique.

  As shown in FIG. 24, the substantial cross-sectional dimension of the spring that affects the strength of the spring, that is, the cross-sectional area of the spring is calculated by multiplying the width dimension and the thickness dimension of the spring element portion 26. However, the width dimension can be accurately controlled by using a photolithographic technique as a processing technique, and the thickness dimension can be controlled extremely accurately because it is determined by the time of electrolysis, and each is accurate to the micron order. . Therefore, the sheet spring of this embodiment with extremely high accuracy can be manufactured. As a result, a planar spring capable of changing a minute pressure into a subtle variation factor can be produced by photoelectroforming.

[safety valve]
In FIG. 25, a safety valve 40 is a self-returning safety valve, and is attached to a valve seat 50 around a gas diffusion hole 46 in a can body 48 of an electrochemical element 44, for example. The safety valve 40 includes, for example, a planar spring 7 (FIG. 11) according to a seventh configuration example, and a valve body 42 that is pressed and urged by the planar spring 7 to a gas diffusion hole (pressure release port). ing. The planar spring 7 is set so as to function accurately even at a fine pressure of 3 to 5 kgf / cm ² . The load receiving portion 22 of the planar spring 7 is formed in a spherical shape corresponding to the valve body 42 which is, for example, a spherical body.

  The shape of the valve body 42 is not limited to a sphere but may be a planar shape or the like, but a corrugated waveform is provided on the surface so that gas can be easily diffused at a contact portion with the gas diffusion hole 46. It is desirable to form it. Moreover, the valve body 42 is comprised with the elastic body. For the material, chemical-resistant plastics such as SBR (styrene butadiene rubber), EPDM (ethylene propylene diene rubber), butyl rubber, fluorine rubber, acrylic rubber, etc., which have been put into practical use so far, may be used. Is possible.

  The valve body 42 is not limited to an elastic body, and may be a rigid body. In that case, it is desirable to arrange an elastic body for improving the sealing performance at the contact portion of the gas diffusing hole 46 with the valve body 42. Further, the valve body 42 may be configured by coating an elastic body on the surface of a rigid body.

  A ring-shaped gasket 52 having an inner diameter larger than that of the valve body 42 is fitted into the concave valve seat 50. The valve body 42 is configured to have a larger diameter than the gas diffusion hole 46 and is disposed so as to close the gas diffusion hole 46. On the gasket 52, the base portion 20 of the planar spring 7 is placed, and the load receiving portion 22 is disposed so as to cover the valve body 42. The planar spring 7 is fixed by a disc spring 54 fitted into the valve seat 50. As shown in FIG. 26, the disc spring 54 is configured in an annular shape having the same size as the base portion 20 of the planar spring 7 so as not to interfere with the load receiving portion 22 of the planar spring 7. On the outer periphery, a plurality of protrusions 56 are bent obliquely upward. The disc spring 54 is fitted to the wall portion of the valve seat 50 at the projection 56.

  In this safety valve 40, during normal use, the planar spring 7 is elastically deformed according to the amount of gas generated in the can body 48 of the electrochemical element 44, so that the valve body 42 moves up and down, and the electrochemical element 44. The pressure in the can 48 can be regulated within the setting. Further, when an abnormality occurs, a large amount of gas is generated in the can body 48, and when an excessive pressure is generated in the can body 48, a rupture portion (not shown) in the planar spring 7 is ruptured. Can open the gas diffusing hole 46 to instantaneously dissipate the pressure. Thereby, the explosion of the electrochemical element 44 can be prevented.

  As described above, the safety valve 40 according to the present embodiment is extremely reliable, can be operated at a low pressure, and only the by-product gas out of various gases generated in the container during normal use is used. Can be instantly dissipated out of the container, and can be applied to ultra small to large electrochemical devices. Further, when an excessive pressure is generated in the target container, the pressure can be instantaneously dissipated.

[Electrochemical element]
In general, an electric double layer capacitor composed of a medium to large-sized bottomed aluminum can of 50 to 1900 F / can is used in industrial equipment such as an automobile, a copying machine, and a robot. In the aluminum can body, a polarizable electrode mainly composed of a pair of activated carbons is housed together with an organic electrolyte solution via a separator. And an electric double layer capacitor is comprised by providing the sealing body equipped with the self-returning type safety valve using the planar spring which concerns on this embodiment in the opening part of this bottomed aluminum can body.

  According to this configuration, when the internal pressure of the electric double layer capacitor reaches a predetermined pressure, the self-recovery safety valve composed of a planar spring is instantaneously operated, and the gas generated inside is diffused to the outside. It is possible to return the internal gas pressure to normal.

  In addition, as described above, the safety valve according to the present embodiment operates at a lower internal gas pressure than the conventional one, has a high response speed, and can be reduced in thickness and size. In addition, by producing a planar spring by electroforming, it is possible to obtain a highly accurate planar spring and to mass-produce the planar spring at a low price. Therefore, the planar spring and the safety valve according to the present embodiment can contribute to demands for weight efficiency, space efficiency, and cost reduction, such as industrial copying machines, robots, and automobiles. Industrial value is extremely large.

(Test example)
The characteristics of the safety valve 40 according to this embodiment were confirmed using an electric double layer capacitor. The electric double layer capacitor is composed of activated carbon as a polarizable electrode, a slurry prepared with acetylene black and an aqueous SRB binder, and coated on a 20 μm Al current collector to a dry thickness of 20 μm. This was dried and stored in a 500 mm Al can having an inner diameter of 35 mm. As an electrolytic solution, an organic electrolytic solution composed of a solute having a concentration of 1 mol / L (liter) of propylene carbonate (PC) as a solvent and tetraethylammonium tetrafluoroborate (TEABF4) was used. In Example 1 and Example 2, the self-returning safety valve 40 according to the present embodiment shown in FIG. 25 was used, and in the conventional examples 1 and 2, a coil-type self-recovering safety valve was used.

  As a test, first, an endurance test of 1000 hours was performed by applying 3.0 V at 70 ° C. where gas generation was large and an accelerated life test was possible. Further, as an abnormal use condition in which a large amount of gas was generated in the electrochemical device, a durability test was conducted at 70 ° C. and 3.3 V for 100 hours. Table 2 shows a comparison of the durability characteristics of the electrochemical elements of the electric double layer capacitor according to each example and each conventional example.

  First, as a result of a 3.0 V application test at 70 ° C. in which gas generation is large and an accelerated life test is possible, the conventional example 1 has a large capacity change rate and an increase in internal resistance. The liquid leakage was severe. However, in Example 1, there was no abnormality in particular. In addition, since gas generation was steadily dissipated outside the can body, there was no swelling of the can body or leakage of the electrolyte solution, and there were no abnormalities in the characteristics, indicating excellent characteristics.

  On the other hand, as an abnormal use condition, as a result of an endurance test at 70 ° C. and 3.3 V for 100 hours, in Conventional Example 2, an explosion occurred after 63 hours and the can body was damaged. However, in Example 2, since abnormal gas generated gas was steadily diffused outside the can body, no abnormality of the can body was observed even after 100 hours had elapsed, and the subsequent test could be continued.

  In the test example, an example of an electric double layer capacitor using an organic electrolyte was shown. Here, the effects of other application examples of the electrochemical element will be described as a general theory.

(For nickel metal hydride batteries)
In the case of a nickel metal hydride battery, there is a risk of battery explosion, especially because the generation of hydrogen gas deteriorates the cycle characteristics of the battery or is weak in heat resistance at 50 ° C. or higher. Conventional coil springs having a response pressure of 8 to 20 kgf / cm ² are commercially available. The response speed with this spring pressure is 150 to 800 msec / time. The planar spring according to the present embodiment can be driven at a slight pressure of ^{3 to 5} kgf / cm ² , so that the response speed can be 20 to 100 msec / time.

For this reason, when the safety valve is opened, the inflow of external air is reduced, and the influence of CO ₂ and H ₂ O from the outside air can be significantly reduced.

(Lithium ion battery)
Since the lithium ion battery uses an organic solvent such as ethyl methyl carbonate (EMC) and LiPF6 (lithium hexafluorophosphate) salt as the solute, as in the case of the electric double layer capacitor, H The influence of ₂ O is great. However, in the safety valve according to the present embodiment, the response pressure of the planar spring is low and the response speed is fast. Therefore, the valve can be opened and closed in a very short time, and is extremely effective for a lithium ion battery.

DESCRIPTION OF SYMBOLS 1 Surface spring 2 Surface spring 3 Surface spring 4 Surface spring 5 Surface spring 6 Surface spring 7 Surface spring 8 Surface spring 9 Surface spring 10 Surface spring 12 Surface spring 13 Surface spring 14 Surface Shape spring 15 Planar spring 16 Planar spring 20 Base 22 Load receiving portion 26 Spring element portion 28 Collapsed portion 40 Safety valve 42 Valve element 44 Electrochemical element 46 Gas diffusion hole X Base size Y Displaceable dimension

Claims (6)

A base formed in a planar and frame shape;
A load receiving portion elastically supported via a plurality of spring element portions on the inner side in the surface direction of the base portion;
A rupture portion provided at at least one of the base, the spring element portion, and the load receiving portion, and ruptured when a predetermined load or more is applied to the load receiving portion;
A planar spring integrally having When the outer dimension of the base is X, and the displaceable dimension of the load receiving part on one side in the thickness direction of the base due to elastic deformation of the spring element part is Y,
The planar spring according to claim 1 , wherein the aspect ratio (Y / X) is 0.1 to 0.5. The planar spring is made of Ni electroformed metal, Ni alloy electroformed alloy, Cu electroformed metal, Cu alloy electroformed alloy, Pd-Ni alloy, Pd-Co alloy or Pd-Ni-Co. The planar spring according to claim 1 or 2 , which is a ternary alloy and is made of an electroformed alloy containing 10 to 90% of Pd. The thickness of the said planar spring is 1-100 micrometers, The planar spring of any one of Claims 1-3 . A planar spring according to any one of claims 1 to 4 ,
A valve body that is pressed and biased to the gas diffusion hole by the planar spring;
Having a safety valve. An electrochemical element having the safety valve according to claim 5 .

Images