JP5592291B2 - Sealed battery and safety valve - Google Patents

Description

  The present invention relates to a sealed battery having a non-returnable safety valve that releases abnormal internal pressure, and a non-returnable safety valve suitable for use in the sealed battery.

  As is well known, various secondary batteries have been proposed as power sources for portable electronic devices and as power sources for electric vehicles and hybrid vehicles. Among such secondary batteries, particularly sealed batteries, a safety valve that operates so as to be cleaved when the internal pressure of the battery case exceeds a predetermined pressure to reduce the internal pressure, so-called non-recovery Often, a safety valve of the type is provided. Such a safety valve functions to discharge gas inside the case by operating in response to an abnormal increase in internal pressure due to gas generated by a chemical reaction of the power generation element. Conventionally, as such a non-returnable safety valve used for a sealed battery, a safety valve described in Patent Document 1 is known.

  In the safety valve described in Patent Document 1, a thin groove having a predetermined shape suitable for cleavage is formed on a valve body made of a stainless steel plate of a predetermined material. And the material yield strength of the said stainless steel plate, the plate | board thickness of a groove part, etc. are determined so that the said groove | channel may open | release in response to the internal pressure of a battery reaching a set value.

JP-A-8-158016

  Like the safety valve described in Patent Document 1, by specifying the material yield strength of the stainless steel plate that will be the valve body, the thickness, shape, etc. of the groove, the accuracy of the pressure at which the safety valve operates, that is, the accuracy of the operating pressure is increased. Will be able to. However, in recent years, with the diversification of battery case materials, the materials used for safety valves have also diversified, such as metal and resin. There is a need for techniques that can be maintained or improved. Moreover, as long as the battery is not only a secondary battery but also a primary battery, as long as it is a sealed battery, it is still necessary to release an abnormal internal pressure. As a result, the accuracy of the operating pressure of such a safety valve is not changed. Maintenance or improvement of this is also a technical issue common to sealed batteries.

  The present invention has been made in view of such circumstances, and its purpose is a sealed battery that can appropriately operate a non-returnable safety valve in response to an abnormal increase in internal pressure as a battery, And providing a non-returnable safety valve suitable for use in the sealed battery.

A sealed battery that solves the above problem is a sealed battery that includes a non-returnable safety valve that releases internal pressure by cleavage, and the safety valve includes a first thin-walled portion formed as a groove in a partition plate; Each of the first thin portions has a second thin portion formed as a polygonal annular groove having a curved corner portion in a manner located on at least two opposite sides of the first thin portion. In the thickness direction of the partition plate, the first thin wall portion and the second thin wall portion are such that the thickness center position of the first thin wall portion is more than the thickness center position of the second thin wall portion. Is located on the inner side of the battery, and the first thin portion is surrounded by the second thin portion and extends to the vicinity of the corner portion of the second thin portion, Having an end that ends in a curved line in the plane direction of the partition plate, Some of the curve forming the corner portion of the curve second thin portion at the end of the first thin portion and is summarized in that which is formed as part of concentric circles.

  According to such a configuration, the second thin wall where the bending point of the first thin-walled portion which is in the partition plate and bends and tears outward by internal pressure is the center of rotation of the partition plate in the external direction. With respect to the bending point of the part, it is provided on the inner side of the battery with respect to the turning direction (cleavage direction). In this way, in the thickness direction of the partition plate, since the bending point of the first thin portion is inside the bending point of the second thin portion, the safety valve is pressed outward by the internal pressure, and the first When the thin portion is about to move outward, a force that is pushed open (compressed) from the first thin portion side is applied to the second thin portion. At this time, if the rigidity of the safety valve is maintained, a force that opposes the pressing force in the external direction applied to the safety valve from the second thin portion side is generated, and the countering force against the pressing force in the external direction is generated. A force is generated, and the movement of the first thin portion toward the outside is suppressed. For this reason, the first thin-walled portion is restrained from moving outwardly until the internal pressure exceeds the opposing force, and hardly deforms and does not cause strain due to fatigue. Does not cleave.

  On the other hand, when the internal pressure increases, due to deformation of the safety valve or the like, the pressing force in the external direction becomes larger than the opposing force, and as a result, in the thickness direction of the partition plate, the first thin portion is It moves to the outside side rather than the thin part of 2. When the first thin part moved to the outside side is greatly bent and deformed, and the tension (force to be torn) due to the internal pressure is applied, the strain becomes large, and the first thin part is not moved to the outside side. Compared to, it becomes easier to cleave.

  Thus, the first thin-walled portion is arranged on the outside side so that the magnitude of strain generated in the first thin-walled portion is reduced in the region where the safety valve is not operated, but is increased in the region where the safety valve is operated. It can be adjusted according to whether or not to move to. That is, by moving the first thin part to the outside in an area where the safety valve is to be operated due to an abnormal internal pressure, the distortion generated in the first thin part is suddenly increased and the safety valve operates. / The area where the inactivation is ambiguous is reduced, and the safety valve can be operated with high accuracy.

  For example, a nickel metal hydride battery varies in internal pressure even during normal use. For this reason, with such a structure, depending on the temperature range and aging during normal use of the nickel-metal hydride battery, the change that occurs in the first thin part is made less than the fatigue strength at which fatigue does not accumulate, and at abnormal pressure, the pressure is reduced to that pressure. It becomes possible to provide a nickel-metal hydride battery with a safety valve adjusted to break upon reaction.

  In addition, since the strain generated in the first thin portion is adjusted by the first thin portion and the second thin portion, adjustment is preferably made so that it can operate suitably as a safety valve regardless of the material of the partition plate. Can do.

  Furthermore, since the safety valve has a structure in which a thin portion is formed on the partition plate, the number of parts is smaller than that of a resettable safety valve, the yield during assembly is good, and the cost can be reduced.

  According to such a configuration, the entire safety valve is easily deformed by the second thin portion, and the adjustment of the pressure for moving the first thin portion toward the outside is facilitated. Regardless of the rigidity of the partition plate, the safety valve can be adjusted to bend and deform according to the internal pressure by adjusting the thickness of the second thin portion. As a result, the safety valve of the sealed battery can be suitably operated regardless of its material.

  According to such a configuration, since the thickness between the first thin portion and the second thin portion in the corner portion becomes uniform, when the first thin portion is moved outward, the same corner is provided. Since the force that bends the part becomes stable, the operation of the safety valve becomes more stable.

Preferably, the first thin portion is formed on the outside of the battery side of the partition plate, said second thin portion, that is formed in the battery inside side of the partition plate.

  According to such a configuration, since the first thin portion is provided on the inner side with respect to the second thin portion, the bending point of the first thin portion is directed outward of the bending point. It becomes easy to provide the second thin-walled portion on the inner side with respect to the bending point of the second thin-walled portion.

Preferably, the partition plate that is integrally formed in the case of the sealed battery.
According to such a configuration, since the safety valve is integrally formed in the case of the sealed battery, the number of parts can be further reduced, the yield at the time of assembly can be improved, and the cost can be reduced.

Preferably, the partition plate ing from the resin plate.
According to such a structure, the safety valve which has a suitable operating characteristic can be provided also in the resin-made sealed battery case. In addition, since the thickness of the portion other than the first thin portion and the second thin portion can be increased, the permeation of gas can be suppressed as compared with a film-like safety valve as a whole. It becomes like this. For example, in the case of a nickel metal hydride battery, the permeation of hydrogen is suppressed, so that the characteristics as a battery can be suitably maintained.

A safety valve that solves the above-described problem is a safety valve that releases pressure inside a container by cleavage, and includes a first thin portion formed as a groove in a partition plate, and at least two opposite sides of the first thin portion. And a second thin portion formed as a polygonal annular groove having a curved corner portion in the partition plate, and the first thin portion and the second thin portion. Means that, in the thickness direction of the partition plate, the thickness center position of the first thin portion is located closer to the inside of the container than the thickness center position of the second thin portion , and the first thin portion The part is surrounded by the second thin part and extends to the vicinity of the corner part of the second thin part and ends in a curved shape in the plane direction of the partition plate And a curve at an end of the first thin portion and the second A portion of the curve forming the corner portion of the thin portion is to subject matter that is formed as part of concentric circles.

  According to such a configuration, the second thin wall where the bending point of the first thin-walled portion which is in the partition plate and bends and tears outward by internal pressure is the center of rotation of the partition plate in the external direction. With respect to the bending point of the part, it is provided on the inner side of the battery with respect to the turning direction (cleavage direction). In this way, in the thickness direction of the partition plate, since the bending point of the first thin portion is inside the bending point of the second thin portion, the safety valve is pressed outward by the internal pressure, and the first When the thin portion is about to move outward, a force that is pushed open (compressed) from the first thin portion side is applied to the second thin portion. At this time, if the rigidity of the safety valve is maintained, a force that opposes the pressing force in the external direction applied to the safety valve from the second thin portion side is generated, and the countering force against the pressing force in the external direction is generated. A force is generated, and the movement of the first thin portion toward the outside is suppressed. For this reason, the first thin-walled portion is restrained from moving outwards until the internal pressure exceeds the opposing force, and is hardly deformed and does not cause strain due to fatigue. Does not occur.

  On the other hand, when the internal pressure increases, due to deformation of the safety valve or the like, the pressing force in the external direction becomes larger than the opposing force, and as a result, in the thickness direction of the partition plate, the first thin portion is It moves to the outside side rather than the thin part of 2. When the first thin part moved to the outside side is greatly bent and deformed, and the tension (force to be torn) due to the internal pressure is applied, the strain becomes large, and the first thin part is not moved to the outside side. Compared to, it becomes easier to cleave.

  Thus, the first thin-walled portion is arranged on the outside side so that the magnitude of strain generated in the first thin-walled portion is reduced in the region where the safety valve is not operated, but is increased in the region where the safety valve is operated. It can be adjusted according to whether or not to move to. That is, by moving the first thin part to the outside in an area where the safety valve is to be operated due to an abnormal internal pressure, the distortion generated in the first thin part is suddenly increased and the safety valve operates. / The area where the inactivation is ambiguous is reduced, and the safety valve can be operated with high accuracy.

  In addition, since the strain generated in the first thin portion is adjusted by the first thin portion and the second thin portion, adjustment is preferably made so that it can operate suitably as a safety valve regardless of the material of the partition plate. Can do.

  Furthermore, since the safety valve has a structure in which a thin portion is formed on the partition plate, the number of parts is smaller than that of a resettable safety valve, the yield during assembly is good, and the cost can be reduced.

  According to a sealed battery having a non-returnable safety valve according to the present invention and a non-returnable safety valve suitable for use in the sealed battery, the internal pressure of a container such as a sealed battery becomes abnormal. In such a case, the safety valve can be appropriately operated in response to the abnormal pressure.

BRIEF DESCRIPTION OF THE DRAWINGS About one Embodiment of the battery module which actualized the sealed battery which has a safety valve of this invention, (a) is a top view which shows the planar structure, (b) is a side view which shows the side structure. It is a figure shown about the cover part of the battery module of the embodiment, (a) is a plan view showing the planar structure, (b) is a side view showing the side structure, (c) is a back view showing the back structure. . It is an enlarged view which shows the structure of the safety valve provided in the cover part of the battery module of the embodiment, (a) is a front view showing the surface structure, (b) is a back view showing the back structure, (c) is The partial enlarged view of the corner part of (b). It is an end view which shows the end surface structure of the safety valve of the embodiment, (a) is an end view which shows the end surface structure in the 4a-4a line of Fig.3 (a), (b) is 4b-4b of Fig.3 (a). The end view which shows the end surface structure in a line. It is the model which shows the operation example of the safety valve of the same embodiment according to the end face structure which is shown in Figure 4 (a), (a) is the figure which shows the state before the deformation, (b) shows the state which started the deformation. The figure which shows, (c) is a figure which shows the state exceeding the yield point, (d) is the figure which shows the state opened by the fracture | rupture. The figure of the graph which shows the distortion which arises in the 1st thin part by the internal pressure concerning the 1st thin part of the safety valve of the embodiment. (A)-(d) The top view which shows the planar structure of other embodiment about the planar structure of the 2nd thin part of the safety valve employ | adopted as the sealed battery of this invention. (A)-(d) The top view which shows the planar structure of other embodiment about the planar structure of the 1st thin part of the safety valve employ | adopted as the sealed battery of this invention. (A)-(d) The end elevation which shows the end surface structure of other embodiment about the end surface structure of the safety valve employ | adopted as the sealed battery of this invention. (A)-(c) The end elevation which shows the end surface structure of other embodiment about the end surface structure of the groove | channel which forms the thin part of the safety valve employ | adopted for the sealed battery of this invention.

Hereinafter, a sealed battery having a non-returnable safety valve according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, the battery module is configured by electrically connecting a plurality of (for example, six) unit cells 14 as sealed batteries in series to obtain a required power capacity. The battery module has a structure in which a plurality of unit cells 14 each having a rectangular parallelepiped shape are arranged such that a short side surface corresponding to the side surface of the unit cell 14 having the largest surface area (long side surface) is opposed to each other. That is, this battery module is configured by connecting six unit cells 14 made of, for example, nickel hydride storage batteries.

  The battery module is made of resin, and includes a resin integrated battery case 10 having an upper opening, and a resin lid body 20 that seals the upper opening of the integrated battery case 10. The integrated battery case 10 is provided with six battery cases that contain power generation elements such as a positive electrode plate, a negative electrode plate, a separator, a current collector plate, and an electrolyte, and an upper surface opening of the integrated battery case 10 is provided. By sealing with the lid 20, the battery cases are partitioned in a non-communication state. That is, each of the six battery cases partitioned in the non-communication state constitutes the unit cell 14. The power generation element in each battery case generates a gas such as hydrogen or oxygen by a chemical reaction caused by charging / discharging of the unit cell 14 or absorbs it on the contrary. For this reason, when an excessive chemical reaction or the like occurs, there is a possibility that gas is excessively generated by the reaction.

  External terminals 12 and 13 are provided on both side surfaces in the longitudinal direction of the battery module, respectively. Since the unit cells 14 are connected in series between the external terminal 12 and the external terminal 13, the total output of the six unit cells 14 is taken out from these external terminals 12 and 13.

The battery module lid 20 is provided with a sensor mounting hole 22 for mounting a sensor for detecting the internal temperature of the battery module.
Moreover, as shown in FIGS. 2 (a) and 2 (b), the battery module lid 20 includes a surface 20a corresponding to the upper surface of the battery module and a battery 20 as shown in FIGS. 2 (b) and 2 (c). And a back surface 20b joined to the integrated battery case 10 of the module. The back surface 20 b of the lid body 20 is partitioned into six battery case lid portions 23 so as to correspond to the respective battery cases of the unit cells 14 formed in the integrated battery case 10. In the present embodiment, the sensor mounting hole 22 is formed in one battery case lid part 23, and safety valves 40 are provided in all the battery case cover parts 23, respectively. The safety valve 40 is cleaved when the internal pressure of the corresponding battery case is not more than the pressure resistance of the battery module (battery case) and becomes an abnormal pressure that exceeds the internal pressure during normal use. The abnormal pressure in the battery case is released. As a result, when the internal pressure of each battery cell 14 sealed by the lid 20 becomes abnormal pressure, the safety valve 40 is cleaved and the abnormal pressure is released, and the internal pressure is reduced to that of the battery case. Exceeding the breakdown voltage is prevented.

  As shown in FIG. 3A, the safety valve 40 has a valve body 41 as a plate-shaped partition plate that partitions the inside and the outside of the unit cell 14. In the present embodiment, the valve body 41 is formed as a resin plate because it is integrally formed with the resin lid body 20. The valve body 41 has a valve outer surface 41a on the outer side of the battery module, that is, on the surface 20a side of the lid body 20, and a first concave groove 42 as a linear groove is formed on the valve outer surface 41a. ing. The first concave groove 42 is formed as a shape composed of two lines intersecting the central portion in the longitudinal direction, and has a curved end at each longitudinal end portion, that is, both side surfaces of the concave groove. It has a curved end portion 42r to be connected. The safety valve 40 has a valve outer surface 41a divided into four compartments 44a to 44d by a first concave groove 42, and the first concave groove 42 between the compartments 44a to 44d. A first thin portion 42 a corresponding to the bottom of 42 is formed.

  As shown in FIG. 3 (b), the safety valve 40 has a valve inner surface 41b on the inner side of the valve body 41, that is, on the back surface 20b side of the lid body 20, and a linear groove on the valve inner surface 41b. The second concave groove 43 is formed. The second concave groove 43 is formed as a rectangular and annular groove, and has a curved corner portion that connects two sides connected by the same corner portion to the four corner portions of the rectangular shape by a curved line. 43r is formed. Moreover, since the 2nd groove 43 is arrange | positioned so that the perimeter of the 1st groove 42 formed in the valve outer surface 41a may be enclosed, the 1st groove 42 and the 2nd groove 43, Do not cross. An extremely thin portion or hole that may be formed by the intersection of the first groove 42 and the second groove 43 because the first groove 42 and the second groove 43 do not intersect. Is not formed. The valve inner surface 41b of the safety valve 40 is divided into an inner peripheral section 45a and an outer peripheral section 45b by the second concave groove 43, and the inner peripheral section 45a and the outer peripheral section are divided by the second concave groove 43. A second thin portion 43a corresponding to the bottom of the second concave groove 43 is formed between the second concave groove 43 and the second thin groove 43. That is, the four sections 44a to 44d formed on the valve outer surface 41a are arranged in the inner peripheral section 45a of the valve inner surface 41b.

  As shown in FIG. 3 (c), the end portion 42r of the first concave groove 42 is an arc whose center is a center point C whose curved surface is set at the end portion 42r of the first concave groove 42. Is formed. Further, the curved surface of the corner portion 43r of the second groove 43 is also formed as an arc centered on the center point C. That is, the curved surface of the terminal end portion 42r of the first concave groove 42 and the curved surface of the corner portion 43r of the second concave groove 43 are formed as a circular arc as a part of a concentric circle. As a result, as shown in FIG. 4B, the safety valve 40 of the groove portion 41c formed between the terminal portion 42r of the first groove 42 and the corner portion 43r of the second groove 43 is provided. The thickness D1 with respect to the planar direction is uniform. Therefore, when the first and second concave grooves 42 and 43 are bent and the valve body 41, that is, the four sections 44a to 44d are moved outward, the force required for bending the inter-groove portion 41c is stabilized. Thus, the bending of the first and second concave grooves 42 and 43 is more stable, and the operation as the safety valve 40 can be stabilized.

  As a result, as shown in FIG. 4A, when a pressure is applied to the valve inner surface 41b from the inside to the outside, the safety valve 40 is thickened in the valve body 41 by the applied pressure. Therefore, stress concentrates on the first thin portion 42a and the second thin portion 43a, particularly the first thin portion 42a, which have low rigidity. The first thin portion 42a has a theoretical bending point L1 at which the first thin portion 42a bends at a substantially central position between the valve inner surface 41b and the bottom surface of the first concave groove 42. Thus, the second thin portion 43a has a theoretical bending point L2 at which the second thin portion 43a bends at a substantially central position between the valve outer surface 41a and the bottom surface of the second concave groove 43. Will have. In addition, since the bending point L1 is disposed on the inner side of the battery than the bending point L2, an offset D2 as a separation distance with respect to the external direction is provided between the bending point L1 and the bending point L2. Note that the bending point L1 and the bending point L2 may not necessarily be substantially at the center of the thickness depending on the shape and material (for example, composite material) of the first thin part 42a and the second thin part 43a. Even in such a case, if the bending point L1 and the bending point L2 move in the same direction from the center position of the thickness, an appropriate offset is provided between the bending point L1 and the bending point L2. That is, if an appropriate offset is provided at the thickness center position, the theoretical bending point L1 at which the first thin portion 42a bends naturally and the theoretical bending point L2 at which the second thin portion 43a bends. Is also provided with an appropriate offset.

  By providing the offset D2 between the bending point L1 and the bending point L2, when the bending point L1 is going to move to the outside direction, the bending point L1 has a bending point along with the force to move to the outside direction. A force is also applied to push the bending point L2 supporting L1 movably in the horizontal direction of the valve body 41. The force that pushes the bending point L2 tries to move the bending point L1 toward the outside of the valve body 41 while the valve body 41 is not bent and the rigidity of the valve body 41 is maintained. The bending point L1 is not moved because a counter force that opposes the force to be generated occurs. On the other hand, if the rigidity of the valve body 41 is not maintained due to the first thin portion 42a or the second thin portion 43a being bent by a force that pushes the bending point L2, the valve body 41 has a bending point. Since the opposing force that opposes the force to move L1 in the external direction is not generated, the bending point L1 is moved in the external direction. Thus, by providing the offset D2, a yield point where only the strain increases without increasing the counterforce is generated in the counterforce-strain curve (see FIG. 6 described later). As a result, when the internal pressure is in the normal use range and does not exceed the yield point, the safety valve is not operated. On the other hand, only when the internal pressure is abnormal pressure and exceeds the yield point, the safety valve is reliably operated. The pressure at the yield point is considered to be the pressure when the bending point L1 and the bending point L2 are at the same height (no offset).

  Next, the operation of the safety valve 40 of the present embodiment will be described with reference to FIGS. FIG. 5 is a simplified illustration of FIG. 4A for the sake of explanation. Further, in FIG. 5, for the convenience of explanation, it is assumed that changes such as bending do not occur on the outer periphery of the second concave groove 43 regardless of the internal pressure of the battery case being any of the pressures P1 to P4.

  The relationship between the magnitudes of the pressures P1 to P4 shown in FIGS. 5A to 5D is shown in a graph 50 in FIG. The graph 50 is provided with a line 51 indicating a relationship in which strain occurs in the first thin portion 42a according to the internal pressure of the battery. As shown in the graph 50, the pressure P1 is a pressure when there is almost no difference from the atmospheric pressure, and the pressure P2 is larger than the pressure P1 and slightly exceeds the normal use region to reach the yield point α1 of the valve body 41. Pressure. Further, the pressure P3 is a pressure at the yield point α1 of the valve body 41 that is higher than the pressure P2, and is an abnormally increased pressure before reaching the battery case destruction region, and the pressure P4 is an abnormally increased pressure. This is the pressure at which the strain becomes the maximum value α2 in the region P3 and the safety valve 40 is cleaved.

As shown in FIG. 5A, when the internal pressure is a pressure P1 close to atmospheric pressure, no special change occurs in the safety valve 40. Therefore, the bending point L1 of the first thin portion 42a and the bending point L1 are the same. The reference position L3 is arranged at the same position with respect to the external direction. For this reason, the distance with respect to the pressurizing direction between the bending point L2 of the second thin portion 43a and the reference position L3 is the same distance as the offset D2. In such a case, the first thin portion 42a and the second thin portion 43a are not greatly bent, so that fatigue does not accumulate there, so that the first thin portion 42a and the second thin portion 43a are not cleaved by fatigue.

  As shown in FIG. 5B, when the internal pressure is the pressure P2 that does not bring the safety valve 40 to the yield point, the valve inner surface 41b of the safety valve 40 is pressurized, and a force is applied to the valve body 41 in the outward direction. At this time, the amount of movement of the second thin portion 43a connected to the outer periphery that does not move is small, and the amount of movement of the central portion of the inner peripheral section 45a, in particular, the first thin portion 42a having low rigidity is the largest. . However, since the valve body 41 opposes the pressing force of the pressure P2 by the counter force generated so as to counter the pressing force of the pressure P2, the first thin portion 42a cannot move greatly in the outward direction. . For this reason, even if the bending point L1 of the first thin portion 42a moves slightly in the pressurizing direction from the reference position L3 of the bending point L1, the bending point of the second thin portion 43a serving as a yield point. Since only L2 is passed, the first thin portion 42a is always given a counter force in the opposite direction to the force in the external direction. As a result, the first thin portion 42a and the second thin portion 43a are not greatly bent outwardly enough to pass the yield point due to the pressure P2, and the generated strain is reduced, and almost no fatigue is accumulated in the member. It will not be cleaved due to fatigue because it will not be or will be a little if accumulated.

  As shown in FIG. 5C, when the internal pressure is the pressure P3 at which the safety valve 40 exceeds the yield point, the valve inner surface 41b of the safety valve 40 is pressurized and a large force is applied to the valve body 41 in the outward direction. Also at this time, the amount of movement of the central portion of the inner peripheral section 45a, in particular, the first thin portion 42a having low rigidity becomes the largest. By the way, when the first thin portion 42a tries to move outward due to the pressing force based on the pressure P3, it receives a counter force from the valve body 41 in the internal direction. Since the force exceeds the counter force, the valve body 41 exceeds the yield point, that is, the bending point L1 passes the bending point L2 in the outside direction, and the first thin portion 42a is greatly bent as it moves greatly in the outside direction. In addition, the first thin portion 42a that has moved beyond the bending point L2 hardly generates a counter force or the like from the valve body 41 in the inner direction, and the first thin portion 42a is pulled (teared) to the left or right. Power will be granted. As described above, in particular, the first thin portion 42a is greatly bent outward and the tension is applied, so that fatigue is accumulated, and the bending point L1 does not exceed the bending point L2. Compared to the above, it becomes a state where it is easy to cleave. In the present embodiment, the second thin portion 43a is also bent, but since the bending angle is smaller than that of the first thin portion 42a, the first thin portion 42a that accumulates more fatigue is cleaved. Yes. Further, the second thin portion 43a is formed so that the valve body 41 that has received the internal pressure is suitably deformed, that is, each section 44a to 44d is centered on the second thin portion 43a and the first thin portion 42a side. Can be moved outward.

  As shown in FIG. 5D, when the internal pressure is the pressure P4 at which the first thin portion 42a is cleaved, the valve inner surface 41b of the safety valve 40 is pressurized, and the first thin portion 42a is directed outward. Along with the force (pressing force), a tension (tear) to the left and right is also applied, and fatigue is accumulated rapidly. When the accumulated fatigue exceeds the limit, the first thin portion 42a is cleaved and the internal gas is discharged as exhaust gas, thereby releasing the internal pressure. Thereby, the internal pressure does not exceed the pressure resistance of the battery case because the internal pressure P4 is lowered (does not reach the battery case destruction region).

Moreover, it is preferable that the thickness D1 of the inter-groove portion 41c is thin. Specifically, the thickness is preferably thinner than the thickness of the partition plate (D3 in FIG. 4A). When the thickness D1 of the inter-groove portion 41c is large, the rise at the yield point in FIG. 6 becomes small, so that the safety valve 40 is not operated in the normal use range, but it is difficult to adjust the safety valve 40 to operate at the abnormal pressure. Because. In FIG. 4B, the thickness of the first thin portion 42a, the thickness of the second thin portion 43a, and the thickness D1 of the inter-groove portion 41c are substantially equal. Thus, it is more preferable that the thickness D1 of the inter-groove portion 41c is the same as or less than that of the first thin portion 42a or the second thin portion 43a because the above effect is remarkably exhibited.

  In the present embodiment, since the first concave groove 42 has a shape in which two linear grooves intersect at the center, the first thin portion 42a also has a shape that intersects at the center. The thin portion 42a is cleaved. By specifying the cleavage point in this way, it becomes easy to adjust the operating pressure at which the cleavage occurs.

As described above, according to the battery terminal of the present embodiment, the effects listed below can be obtained.
(1) The second thin wall portion in which the bending point L1 of the first thin wall portion 42a which is in the valve body 41 and bends and tears outward by internal pressure is the center of rotation of the valve body 41 in the external direction. With respect to the bending point L2 of 43a, it comes to be provided in the inside of the cell 14 with respect to the turning direction (cleavage direction). Thus, since the bending point L1 of the first thin part 42a is located inside the second thin part 43a than the bending point L2, the safety valve 40 is pressed outward by the internal pressure, and the first thin part 42a. When moving toward the outside, a force that is pushed open (compressed) from the first thin portion 42a side is applied to the second thin portion 43a. At this time, if the rigidity of the safety valve 40 is maintained, a force that opposes the pressing force in the external direction applied to the safety valve 40 from the second thin portion 43a side is generated, and the outside of the first thin portion 42a. A counter force that opposes the pressing force in the direction is generated, and the movement of the first thin portion 42a in the external direction is suppressed. For this reason, the first thin-walled portion 42a is restrained from moving outward until the pressing force exceeds the opposing force, hardly deforms, and is not strained by fatigue. Therefore, the first thin-walled portion 42a is not deformed. No cleavage occurs.

  On the other hand, when the internal pressure is increased, the safety valve 40 is deformed, and when the pressing force in the external direction is greater than the opposing force, the first thin portion 42a becomes the second thin wall. It moves to the outside from the part 43a. The first thin portion 42a moved to the outside side is greatly bent and deformed, and a strain (force to be torn) due to internal pressure is applied to the first thin portion 42a. Compared to, it becomes easier to cleave.

  As a result, the first thin-walled portion 42a is externally reduced so that the magnitude of the strain generated in the first thin-walled portion 42a is reduced in the region where the safety valve 40 is not operated, but is increased in the region where the safety valve 40 is operated. It can be adjusted depending on whether or not it moves to the side. That is, the thickness and positional relationship of the first and second thin portions 42a and 43a are adjusted so that the first thin portion 42a is moved to the outside in an area where the safety valve 40 is to be operated due to an abnormal internal pressure. As a result, the distortion generated in the first thin portion 42a is suddenly greatly increased, the area where the operation / non-operation of the safety valve 40 is ambiguous is reduced, and the safety valve 40 can be operated with high accuracy. Become.

  The nickel metal hydride battery has a variation in internal pressure even during normal use. For this reason, with such a structure, depending on the temperature range and aging during normal use of the nickel metal hydride battery, the change that occurs in the first thin portion 42a is reduced below the fatigue strength at which fatigue does not accumulate, and the pressure at the time of abnormal pressure The safety valve 40 adjusted to break in response to the above can be provided in the nickel metal hydride battery.

(2) Since the first thin-walled portion 42a and the second thin-walled portion 43a adjust the strain generated in the first thin-walled portion 42a, it operates suitably as the safety valve 40 regardless of the material of the valve body 41 and the like. Can be adjusted to. Further, since the safety valve 40 has a structure in which a thin portion is formed on the valve body 41, the number of parts is smaller than that of a resettable safety valve, the yield during assembly is good, and the cost can be reduced.

  (3) Since the first thin portion 42a is configured in a linear shape branched into a plurality, the pressure at which the first thin portion moves toward the outside is adjusted, that is, the first thin portion The degree of freedom in adjusting the distortion generated in the portion 42a to a characteristic that suddenly rises is improved.

  (4) By providing the second thin portion 43a as an annular groove, the entire safety valve 40 is easily deformed by the second thin portion 43a, and the first thin portion 42a is moved outward. It is easy to adjust the pressure to be applied. Regardless of the rigidity of the valve body 41, the safety valve 40 can be adjusted to bend and deform according to the internal pressure by adjusting the thickness of the second thin portion 43a. As a result, the safety valve 40 of the sealed battery can be suitably operated regardless of its material.

  (5) Since the thickness between the first thin portion 42a and the second thin portion 43a in the corner portion 43r is uniform, the corner portion is moved when the first thin portion 42a is moved outward. Since the force that bends 43r becomes stable, the operation of the safety valve 40 becomes more stable.

  (6) Since the first concave groove 42 is formed on the valve outer surface 41a and the second concave groove 43 is formed on the valve inner surface 41b, the first thin portion 42a is located on the inner side with respect to the second thin portion 43a. It is easy to provide the bending point L1 of the first thin portion 42a on the inner side with respect to the bending point L2 of the second thin portion 43a, which is the turning center of the first thin portion 42a in the outward direction. Become.

(7) Since the safety valve 40 is integrally formed with the case of the sealed battery, the number of parts can be further reduced, the yield in assembling can be improved, and the cost can be reduced.
(8) The safety valve 40 having suitable operating characteristics is also provided for the resin battery module. In addition, since the thickness of the portion other than the first thin portion 42a and the second thin portion 43a can be increased, gas such as hydrogen and oxygen can be used as compared with a film-like safety valve as a whole. Transmission can be suppressed. Thereby, if it is a nickel metal hydride battery, since the permeation | transmission of hydrogen comes to be suppressed, the characteristic as a battery can be suitably maintained now.

(Other embodiments)
In addition, the said embodiment can also be implemented with the following aspects.
In the above embodiment, the case where the second concave groove 43 is a linear groove having a rectangular ring shape is illustrated. However, the present invention is not limited to this, and the second groove may be a polygonal shape or any other shape as long as the second groove is positioned at least on two opposite sides of the first groove in the partition plate plane direction (the direction parallel to the plane of FIG. 3). Any shape such as a circle or a plurality of lines may be used. For example, as shown in FIGS. 7A to 7D, the second concave groove may be a pair of parallel linear grooves 60, or a pair of parallel straight lines and two connecting them. It may be a linear groove 61 made of a curve, a circular linear groove 62, or an elliptical linear groove 63. This increases the degree of freedom in designing the safety valve.

In the above embodiment, the case where the first concave groove 42 is a linear groove in which two lines intersect at the center is illustrated. However, the present invention is not limited to this, and the first groove may have any shape as long as at least the side in the longitudinal direction is surrounded by the second groove. For example, as shown in FIG. 8 (a), the first groove has a linear shape in which two lines intersect at the center and the angle formed by them is greatly different from the above embodiment. The groove 70 may be used. Also,
As shown in FIGS. 8B to 8D, the first concave groove may be a linear groove 71 whose both ends are branched in two, or both ends are branched in three. It may be a linear groove 72 or a single linear groove 73. This increases the degree of freedom in designing the safety valve.

  Adjusting the pressure at which the first thin portion moves in the external direction when the groove (first thin portion) is configured in a linear shape branched into a plurality of grooves, such as the grooves 71 and 72; That is, the degree of freedom in adjusting the distortion generated in the first thin portion to a characteristic that suddenly rises is improved.

  In the above embodiment, the case where the first concave groove 42 is formed on the valve outer surface 41a and the second concave groove 43 is formed on the valve inner surface 41b is illustrated. However, the present invention is not limited to this, and the first groove and the second groove may be formed on the valve outer surface or the valve inner surface as long as the bending point L1 can be arranged on the inner side of the bending point L2. May be. This increases the degree of freedom in designing the safety valve.

  For example, as shown to Fig.9 (a), you may provide both the 1st ditch | groove 80 and the 2nd ditch | groove 81 shallower than it in the valve | bulb outer surface. Accordingly, the first thin portion 80a corresponding to the first concave groove 80 is thinner than the second thin portion 81a corresponding to the second concave groove 81, and therefore the bending point L1 of the first thin portion 80a. Can be arranged on the inner side of the bending point L2 of the second thin portion 81a.

  Further, as shown in FIG. 9B, both the first groove 82 and the second groove 83 deeper than the first groove 82 may be provided on the valve inner surface. Accordingly, the first thin portion 82a corresponding to the first concave groove 82 is thicker than the second thin portion 83a corresponding to the second concave groove 83, and therefore the bending point L1 of the first thin portion 82a. Can be arranged on the inner side of the bending point L2 of the second thin portion 83a.

  Further, as shown in FIG. 9C, the first concave groove 84 is provided on the outer surface of the valve, the second concave groove 85 is provided on the inner surface of the valve, and the first thin portion corresponding to the first concave groove 84 is provided. A groove for further thinning 84a may be formed on the valve inner surface side, and a groove for further thinning the second thin portion 85a corresponding to the second concave groove 85 may be formed on the valve outer surface side. Thereby, since the 1st thin part 84a corresponding to the 1st ditch | groove 84 is formed inside the 2nd thin part 85a corresponding to the 2nd ditch | groove 85, the 1st thin part 84a is formed. The bending point L1 can be disposed more inside than the bending point L2 of the second thin portion 85a.

  Further, as shown in FIG. 9D, as in the above embodiment, the first concave groove 42 is provided on the valve outer surface, the second concave groove 43 is provided on the valve inner surface, and the first concave groove 42 and Another groove 86 may be formed on the valve outer surface between the second concave groove 83. Thereby, the rigidity of the valve body can be adjusted.

  In the above embodiment, the case where the groove shape forming the first groove 42 and the second groove 43 has a substantially rectangular cross-sectional shape is illustrated. However, the present invention is not limited to this, and the groove shape of the first or second groove may be any shape as long as the first thin portion and the second thin portion can be formed in an appropriate shape. May be. For example, as shown in FIGS. 10A to 10C, the groove shape of the first and second concave grooves may be a rectangular groove 90 or a tapered shape. The groove 91 may be a groove 92 including a circular shape at least partially, or may be a shape in which at least two of these shapes are combined or shared. This increases the degree of freedom in designing the safety valve.

In the above embodiment, the case where the outer periphery of the second groove 43 does not bend regardless of the internal pressure of the battery case P1 to P4 in FIG. 5 is not limited to this. The outer periphery may be bent according to the pressure. If the safety valve can be set so that the valve body deforms beyond the yield point when the internal pressure during normal use is exceeded, the outer peripheral section, the inner peripheral section, the first and Any part of the valve body, such as the thin-walled portion 2, may be deformed. This increases the degree of freedom in designing the safety valve.

  In the above embodiment, the battery module is made of resin, that is, the case where the integrated battery case 10 and the lid body 20 are made of resin. However, the present invention is not limited thereto, and the integrated battery case and the lid body are made of resin such as metal. It may be formed of other materials. Thereby, the kind of battery module which has a safety valve can be expanded now.

  In the above embodiment, the case where the material of the safety valve 40 and the material of the lid 20 are the same is illustrated. However, the present invention is not limited to this, and the material of the safety valve and the material of the lid may be different. In this case, different materials may be integrally formed, or a safety valve may be attached to the lid. This increases the degree of freedom in designing the safety valve.

  In the above-described embodiment, the case where the safety valve 40 is integrally formed with the lid 20 is illustrated, but the present invention is not limited thereto, and the safety valve may be separately formed and attached to the lid. This also increases the degree of freedom in designing the safety valve.

  In the above embodiment, the case where a safety valve is provided for each unit cell 14 has been illustrated. However, the present invention is not limited thereto, and in the battery module, when the battery case of each unit cell is communicated, the safety valve is communicated. Only one may be provided for the battery case. Moreover, in a battery module composed of a plurality of non-communication single cells, such a safety valve may be provided only in a part of the single cells. This increases the degree of freedom in designing the safety valve in the sealed battery.

  -In the said embodiment, the battery module comprised by electrically connecting the six cell 14 directly was illustrated. However, the present invention is not limited to this, and the number of single cells constituting the battery module may be less than six, or conversely, may be more than six. Thereby, the kind of battery module etc. in which a safety valve is adopted are expanded.

  In the above embodiment, the case where a safety valve is provided in a battery module in which a plurality of unit cells 14 are connected is illustrated, but the present invention is not limited thereto, and the safety valve is a battery module composed of only one unit cell or a unit cell other than a battery module. It can also be provided in the battery case. Thereby, the kind of battery to which the safety valve is applied can be expanded to various batteries.

  -In the above-mentioned embodiment, although illustrated about the case where it is a battery module consisting of a nickel metal hydride battery, as a battery, such as a battery module, it is a secondary battery (storage battery), such as a nickel cadmium battery and a lithium ion battery. There may be. Thereby, the application range of this battery terminal and a battery using the same is expanded.

In the above embodiment, the case where the battery is a secondary battery has been illustrated, but the present invention is not limited thereto, and the battery may be a primary battery.
In the above embodiment, the case where the safety valve 40 is used for a sealed battery is illustrated, but the present invention is not limited thereto, and such a safety valve is a sealed type in which the internal pressure may be abnormally increased according to the sealed battery. It can also be used for containers. Thereby, the adoption possibility of such a safety valve is increased.

  DESCRIPTION OF SYMBOLS 10 ... Integrated battery case 12, 13 ... External terminal, 14 ... Single cell, 20 ... Lid body, 20a ... Front surface, 20b ... Back surface, 22 ... Sensor mounting hole, 23 ... Battery case cover part, 40 ... Safety valve, 41 ... Valve body, 41a ... valve outer surface, 41b ... valve inner surface, 41c ... inter-groove part, 42 ... first groove, 42a ... first thin part, 42r ... terminal part, 43 ... second groove, 43a ... 2nd thin part, 43r ... corner part, 44a-44d ... division, 45a ... inner periphery part division, 45b ... outer periphery part division, C ... center point, D2 ... offset, L1, L2 ... bending point, L3 ... reference position .

Claims (5)

A sealed battery with a non-returnable safety valve that releases internal pressure by cleavage,
The safety valve has a first thin-walled portion formed as a groove in the partition plate, and a polygon having curved corner portions on the partition plate in an aspect located at least on two opposite sides of the first thin-walled portion. Each having a second thin portion formed as an annular groove of
In the thickness direction of the partition plate, the first thin-walled portion and the second thin-walled portion are such that the thickness center position of the first thin-walled portion is greater than the thickness center position of the second thin-walled portion. Located inside the battery ,
The first thin-walled portion is surrounded by the second thin-walled portion, and extends to the vicinity of the corner portion of the second thin-walled portion, and is curved in the plane direction of the partition plate Having an end that terminates in
A sealed battery characterized in that a curve at an end of the first thin part and a part of a curve forming a corner part of the second thin part are formed as a part of a concentric circle . The first thin portion is formed on the battery outside of the partition plate,
The sealed battery according to claim 1, wherein the second thin portion is formed on a battery inner side of the partition plate. The partition plate is sealed battery according to claim 1 or 2 are integrally formed on the case of the sealed battery. The sealed battery according to any one of claims 1 to 3, wherein the partition plate is made of a resin plate. A safety valve that releases the pressure inside the container by cleaving;
A first thin-walled portion formed as a groove in the partition plate, and a polygonal annular groove having curved corner portions in the partition plate in an aspect located on at least two opposite sides of the first thin-walled portion Each having a second thin-walled portion formed as
In the thickness direction of the partition plate, the first thin-walled portion and the second thin-walled portion are such that the thickness center position of the first thin-walled portion is greater than the thickness center position of the second thin-walled portion. located inside of the container
,
The first thin-walled portion is surrounded by the second thin-walled portion, and extends to the vicinity of the corner portion of the second thin-walled portion, and is curved in the plane direction of the partition plate Having an end that terminates in
A safety valve , wherein a curve at an end of the first thin portion and a part of a curve forming a corner portion of the second thin portion are formed as a part of a concentric circle .

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