JP2015069716A - Safety valve of sealed battery - Google Patents

Abstract

To provide a safety valve for a sealed battery capable of stably securing an opening area at the time of breakage. A safety valve 4 of a sealed battery is provided on a lid 3 that closes an opening of a container that accommodates an electrode body. The safety valve 4 includes a thin portion 40 formed with a thickness smaller than the thickness of the general portion 31 of the lid 3, a linear groove portion 41 formed linearly in the thin portion 40, and a thin portion 40. In the pair of V-shaped groove portions 42 that are branched into two from the both ends 411 of the linear groove portion 41 and spread in a V shape, and in the thin-walled portion 40, a straight line is formed from the pair of tip portions 421 of the V-shaped groove portion 42. A pair of extended groove portions 43 formed to extend to the outer side opposite to the central side where the groove portions 41 are located are provided. [Selection] Figure 2

Description

  The present invention relates to a safety valve for a sealed battery provided in a lid that closes an opening of a container that accommodates an electrode body.

  In a sealed battery such as a lithium ion battery, a safety valve that opens when the internal pressure inside the sealed battery increases is provided in order to prevent the sealed battery from bursting in the event of an abnormality. As the structure of this safety valve, a thin part with a reduced thickness is provided in the lid that closes the opening of the container of the sealed battery, and stress concentration occurs in the thin part when the internal pressure rises and breaks. A material in which a fracture groove is formed is often used.

For example, in the sealed battery of Patent Document 1, a safety valve that is opened when the internal pressure of the case rises above a predetermined level is formed in a part of the case. The thin wall portion constituting the safety valve is formed with a fracture groove for releasing the internal pressure when the safety valve is operated. The breaking groove part is formed by a central straight groove part and a pair of side groove parts connected to the central straight groove part.
Further, for example, in the sealing plate and the sealed battery of Patent Document 2, a valve having a curved portion is formed in the plate portion that closes the opening of the container, and the curved portion is arranged on both sides of the valve over the entire length. It is described that the groove is formed in the state of being formed. In this sealed battery, the stress applied from the outside is relieved by the deformation of the curved portion of the valve, and the stress is prevented from concentrating in the groove.

JP 2010-282851 A Japanese Patent No. 3943063

  However, in the safety valve shown in the above-mentioned Patent Documents 1 and 2, etc., in which the central groove portion and the break groove portion composed of a pair of side groove portions are formed, the area of each thin portion located on both sides of the central straight groove portion is It is larger than the area of each thin part located outside the pair of side grooves. The thin wall portions located on both sides of the central straight groove portion are susceptible to a force due to internal pressure when the safety valve is operated, while the thin valve portions located outside the pair of side groove portions are operated with the safety valve. Less susceptible to internal pressure when For this reason, when the safety valve is activated (when broken), the portions of the thin portions located outside the pair of side groove portions are difficult to open, and the opening area for releasing the internal pressure of the battery may be reduced.

  The present invention has been made in view of such a background, and has been obtained in an attempt to provide a safety valve for a sealed battery that can stably secure an opening area at the time of breakage.

One aspect of the present invention is a safety valve for a sealed battery provided in a lid that closes an opening of a container that houses an electrode body,
A thin-walled portion formed by reducing the thickness from the thickness of the general portion of the lid,
In the thin-walled portion, a linear groove portion formed linearly,
In the thin portion, a pair of V-shaped groove portions formed by branching from the both ends of the linear groove portion into two and spreading in a V shape,
The thin-walled portion includes a pair of extended groove portions formed by extending from a pair of tip portions of the V-shaped groove portion to an outer side opposite to a central side where the linear groove portion is located. The feature is in the safety valve of the sealed battery.

The sealed battery safety valve has a pair of extended groove portions formed by extending from a pair of tip portions of the V-shaped groove portion in a thin-walled portion formed with a linear groove portion and a pair of V-shaped groove portions. . The pair of extending groove portions are formed to extend to the outer side opposite to the central side where the linear groove portion is located.
When the internal pressure of the sealed battery rises and the safety valve operates (breaks), the thin portion (hereinafter referred to as the first portion of the thin portion) located on both sides of the linear groove has a large area. Therefore, it is easy to apply force due to internal pressure. Therefore, it is considered that when the linear groove portion, the pair of V-shaped groove portions, and the extended groove portions are broken, the first portion of the thin portion is easily opened.

On the other hand, the portion of the thin portion including the triangular portion formed by the V-shaped groove portion (hereinafter referred to as the second portion of the thin portion) has a smaller area than the first portion of the thin portion, so that a force due to internal pressure is applied. Hateful. Thus, when each V-shaped groove portion breaks, the pair of extended groove portions formed extending from each V-shaped groove portion also breaks, thereby increasing the amount of opening of the second portion of the thin portion.
In this way, in addition to the first portion of the thin portion, the second portion of the thin portion is also easily opened, so that the first portion and the second portion of the thin portion are opened and the safety valve is opened. Sometimes, an opening area for releasing the internal pressure of the sealed battery can be stably secured.

  Therefore, according to the sealed battery safety valve, the opening area at the time of breakage can be stably secured.

The perspective view which shows the sealed battery concerning an Example. The top view which shows the safety valve in which the linear groove part, the V-shaped groove part, and the extension groove part concerning the Example were formed. Sectional drawing which shows the safety valve in which the linear groove part, the V-shaped groove part, and the extension groove part concerning the Example were formed. The top view which shows the state which the safety valve act | operated (breaking) concerning an Example. Sectional drawing which shows the state which the safety valve concerning the Example act | operates and the 1st part and 2nd part of a thin part opened. The top view which shows the safety valve in which the auxiliary | assistant groove part was formed other than the linear groove part, the V-shaped groove part, and the extension groove part concerning an Example. The top view which shows the safety valve by which the bending part was formed in the front-end | tip part of the V-shaped groove part concerning an Example.

A preferred embodiment of the above-described sealed battery safety valve will be described.
In the sealed battery safety valve, the pair of tip portions of the V-shaped groove may be bent outwardly perpendicular to the linear groove.
In this case, since the length of the tip portion bent outward is short, the same effect as that of the V-shaped groove portion having the tip portion not bent can be obtained.

Moreover, the said thin part is formed in square shape, and the said linear groove part and the said extension groove part may be formed along a pair of parallel side part mutually parallel of the said thin part.
In this case, when the safety valve is operated, the first portion of the thin portion located on both sides of the linear groove portion can be opened along the pair of parallel sides of the thin portion. Thereby, the opening amount of the 1st part of a thin part can be ensured easily.

Moreover, the said linear groove part, the said V-shaped groove part, and the said extension groove part may be formed in the outer surface of the said cover body.
In this case, the structure of the safety valve is simple, and both the first part of the thin part located on both sides of the linear groove part and the second part of the thin part including the triangular part by the V-shaped groove part are provided. However, it can be easily opened.

Hereinafter, embodiments of a safety valve for a sealed battery will be described with reference to the drawings.
As shown in FIG. 1, the safety valve 4 of the sealed battery 1 of this example is provided on the lid 3 that closes the opening 21 of the container 2 that houses the electrode body 22. As shown in FIGS. 2 and 3, the safety valve 4 includes a thin portion 40 that is formed with a thickness smaller than the thickness of the general portion 31 of the lid 3, and a linear shape that is linearly formed in the thin portion 40. In the groove portion 41 and the thin-walled portion 40, a pair of V-shaped groove portions 42 formed by branching from the both ends 411 of the linear groove portion 41 into two and expanding in a V-shape, and in the thin-walled portion 40, the V-shaped groove portion 42 A pair of extended groove portions 43 are formed to extend from the pair of tip portions 421 to the outer side opposite to the central side where the linear groove portion 41 is located.

Hereinafter, the safety valve 4 of the sealed battery 1 of this example will be described in detail with reference to FIGS.
As shown in FIG. 1, the sealed battery 1 of the present example is a lithium ion secondary battery as a storage battery, and an electrode body 22, an electrolytic solution, and a container 2 formed of an aluminum material, a stainless material, or the like. The positive side and negative side internal terminals 23 are arranged. The internal terminal 23 is joined to the electrode body 22 and is provided in a state where the lid body 3 is insulated. The lid 3 is made of an aluminum material, a stainless material, or the like. The lid 3 is provided with an external terminal 24 that is electrically connected to the internal terminal 23 and forms a plus-side electrode and a minus-side electrode in an insulated state from the lid 3.

  The safety valve 4 operates when the internal pressure (internal pressure) of the sealed battery 1 rises above a specified value due to some abnormality, and releases the internal pressure of the sealed battery 1. The safety valve 4 is formed in the center portion of the lid 3, and the external terminals 24 are provided on both sides of the safety valve 4 in the lid 3. Arrangement holes 32 are formed in the lid 3 at positions where the plus-side external terminals 24 are arranged and positions where the minus-side external terminals 24 are arranged. The container 2 is formed in a rectangular parallelepiped shape, and the lid body 3 is formed in a shape along the square shape formed in the opening 21 of the container 2. Further, the plus-side internal terminal 23 and the minus-side internal terminal 23 are arranged at positions separated from each other in the lid 3.

As shown in FIGS. 1 and 2, the lid 3 has a rectangular shape that is long in the direction in which the pair of external terminals 24 are arranged. The thin portion 40 constituting the safety valve 4 is formed in a quadrangular shape by a pair of parallel side portions 45 parallel to each other and a pair of orthogonal side portions 46 orthogonal to the pair of parallel side portions 45. The pair of parallel side portions 45 of the thin wall portion 40 is formed along the long side portion 311 of the quadrangular lid 3.
Four corners 47 of the rectangular thin portion 40 are formed in an R shape. In the thin portion 40, a pair of parallel side portions 45 are formed longer than a pair of orthogonal side portions 46, and the pair of parallel side portions 45 are arranged in parallel with the long side portion 311 of the lid 3. The linear grooves 41, the V-shaped grooves 42, and the extended grooves 43 are formed on the outer surface 301 of the lid 3.

  In addition, although illustration is abbreviate | omitted, a pair of orthogonal side part 46 of the thin part 40 can also be formed in the curved shape which swells outside besides forming in linear form. Further, the pair of parallel side portions 45 and the orthogonal side portions 46 of the thin portion 40 can be formed to bulge outward so that the entire thin portion 40 has an elliptical shape.

The linear groove 41 is formed in parallel to the pair of parallel sides 45 at the center position between the pair of parallel sides 45 in the thin portion 40. Each V-shaped groove portion 42 is formed by a branched portion 420 that branches into two from both end portions 411 of the linear groove portion 41. Each extended groove portion 43 extends from each branch portion 420 and is formed to the vicinity of the R-shaped corner portion 47 of the thin portion 40.
Each extension groove 43 is formed in parallel with the pair of parallel sides 45 in the vicinity of the pair of parallel sides 45 in the thin portion 40. As shown in FIG. 3, the linear groove portion 41, each V-shaped groove portion 42, and each extended groove portion 43 are formed in a V-shaped cross section with a pair of inclined surfaces. The depth of the linear groove part 41, each V-shaped groove part 42, and each extension groove part 43 is constant. The bottoms of the linear groove portions 41, the V-shaped groove portions 42, and the extended groove portions 43 may be formed in a flat shape or a curved shape.

  The first portion 401 of the thin portion 40 located on both sides of the linear groove portion 41 is formed in a trapezoidal shape surrounded by the linear groove portion 41, each V-shaped groove portion 42, and each parallel side portion 45. Further, the second portion 402 of the thin portion 40 including the triangular portion by the V-shaped groove portion 42 is a triangular shape with a straight portion surrounded by each V-shaped groove portion 42, each extended groove portion 43 and each orthogonal side portion 46. Is formed. The distal end portion 431 of each extension groove portion 43 is located at a starting point when the second portion 402 of the thin portion 40 is bent when the safety valve 4 is broken and opened.

Next, the effect of the safety valve 4 of this example will be described.
When the internal pressure of the sealed battery 1 rises abnormally for some reason and the safety valve 4 operates (breaks), the first portion 401 of the thin-walled portion 40 has a large area, so that a force due to the internal pressure is easily applied. Therefore, when the linear groove part 41, a pair of V-shaped groove part 42, and each extension groove part 43 fracture | rupture, it is thought that the 1st part 401 of the thin part 40 opens easily. At this time, the first portion 401 opens to the outside of the lid 3 by 90 ° or more along the parallel side portion 45. Here, FIGS. 4 and 5 show a state in which the safety valve 4 is activated to form the opening hole 400.

  On the other hand, since the second portion 402 of the thin portion 40 has a smaller area than the first portion 401 of the thin portion 40, it is difficult to apply a force due to internal pressure. Therefore, when each V-shaped groove portion 42 breaks, the pair of extended groove portions 43 formed by extending from each V-shaped groove portion 42 also breaks, thereby increasing the amount of opening of the second portion 402 of the thin portion 40. can do. At this time, the second portion 402 opens to the outside of the lid 3 by 90 ° or more along the orthogonal side portion 46.

Thus, in addition to the first portion 401 of the thin portion 40, the second portion 402 of the thin portion 40 is also easily opened, so that the first portion 401 and the second portion 402 of the thin portion 40 are When opened and the safety valve 4 is opened, the opening area X for releasing the internal pressure of the sealed battery 1 can be stably secured (see FIG. 4).
Therefore, according to the safety valve 4 of the sealed battery 1 of the present example, the opening area at the time of breakage can be stably secured.

Further, when the safety valve 4 is actuated, in order to make the second portion 402 of the thin wall portion 40 easier to open, the following device can be devised.
Specifically, as shown in FIG. 6, in the thin-walled portion 40, a pair of auxiliary groove portions 44 are formed linearly between the two tip portions 431 of the extension groove portion 43 so as to be orthogonal to the linear groove portion 41. can do. The pair of auxiliary groove portions 44 can be formed in the vicinity of the pair of orthogonal side portions 46 of the thin portion 40 and in parallel with the pair of orthogonal side portions 46. Further, the pair of auxiliary groove portions 44 are portions that serve as starting points for bending when the second portion 40 of the thin portion 40 is opened. The pair of auxiliary groove portions 44 are shallower than the depth of the linear groove portion 41, the pair of V-shaped groove portions 42, and the extended groove portions 43 so as not to break when the second portion 40 of the thin-walled portion 40 is opened. It can be formed in depth.

  Further, as shown in FIG. 7, a bent portion 422 that is bent outwardly perpendicular to the linear groove portion 41 can be formed at the tip portion 421 of the V-shaped groove portion 42. The extension groove 43 can also be formed extending from the bent portion 422. In this case, since the length of the bent portion 422 is short, it is possible to obtain the same effect as when the extended groove portion 43 is formed from the tip portion 421 that does not have the bent portion 422.

DESCRIPTION OF SYMBOLS 1 Sealed battery 2 Container 21 Opening part 22 Electrode body 3 Cover body 301 Outer surface 31 General part 4 Safety valve 40 Thin part 401 1st part 402 2nd part 41 Linear groove part 42 V-shaped groove part 43 Extension groove part

Claims (4)

A safety valve for a sealed battery provided in a lid that closes an opening of a container that houses an electrode body,
A thin-walled portion formed by reducing the thickness from the thickness of the general portion of the lid,
In the thin-walled portion, a linear groove portion formed linearly,
In the thin portion, a pair of V-shaped groove portions formed by branching from the both ends of the linear groove portion into two and spreading in a V shape,
The thin-walled portion includes a pair of extended groove portions formed by extending from a pair of tip portions of the V-shaped groove portion to an outer side opposite to a central side where the linear groove portion is located. Features a sealed battery safety valve.   2. The safety valve for a sealed battery according to claim 1, wherein a pair of tip portions of the V-shaped groove are bent outwardly perpendicular to the linear groove. The thin portion is formed in a quadrangular shape,
3. The safety valve for a sealed battery according to claim 1, wherein the linear groove portion and the extended groove portion are formed along a pair of parallel sides of the thin portion that are parallel to each other.   The said linear groove part, the said V-shaped groove part, and the said extension groove part are formed in the outer surface of the said cover body, The safety valve of the sealed battery as described in any one of Claims 1-3 characterized by the above-mentioned.

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