JP6851058B2 - Film exterior battery - Google Patents

Description

The present invention relates to a film exterior battery having an exterior film as an exterior body.

In recent years, with the widespread use of various mobile devices such as mobile phones, notebook-type and tablet-type personal computers, it is strongly desired to reduce the weight and thickness of the secondary battery used as a power source for the mobile device. Therefore, as a secondary battery, a film exterior battery using a metal film or a laminated film obtained by laminating a metal thin film and a heat-sealing resin film as an exterior body is increasing instead of the conventional metal can.

Generally, a film exterior battery has a structure in which a sheet-shaped positive electrode and a negative electrode are laminated or wound with a separator in between, and are sealed inside an exterior film which is an exterior body together with an electrolytic solution. External terminals (positive electrode terminal and negative electrode terminal) connected to the positive electrode and the negative electrode are drawn out from the exterior film via the electrode extraction tab.

By the way, it is known that when a secondary battery is overcharged or discharged beyond the standard value or exposed to a high temperature environment, gas is generated by electrolysis or thermal decomposition of the electrolytic solution and the internal pressure rises. Has been done. As the film exterior battery, as described above, an exterior film such as a metal film or a laminated film having flexibility and flexibility is used for the exterior body. Therefore, when the internal pressure rises due to the generation of gas, the exterior film expands, and in the worst case, it may burst. At this time, depending on the rupture location, the ejected gas may adversely affect the surrounding electric circuit, substrate, etc. Therefore, in the film exterior battery, the direction intended before the rupture occurs (for example, the electric circuit, substrate, etc.). It is desirable to release (vent) the gas in a direction that does not exist.

A configuration in which the film exterior battery is provided with a vent mechanism (open valve) is proposed in Patent Documents 1 to 4, for example.
In Patent Documents 1 and 2, two non-heat-sealed portions that are not heat-sealed and communicate with the inside are provided on one side of the outer periphery of the film exterior battery sealed by heat-sealing, and the two non-bonded portions are provided. A configuration is described in which a heat-sealed portion (fixed portion) having a through hole provided between the fused portions is arranged. Further, Patent Document 2 describes a configuration in which a through hole is provided in the vicinity of external terminals (positive electrode terminal and negative electrode terminal) drawn from two opposite sides of the outer periphery of the film exterior battery.

Patent Document 3 has a configuration in which a vent portion in which exterior films are fixed to each other is provided inside a fixed portion (heat-sealed portion) on the outer periphery of the film exterior battery, and a through hole is provided in the vent portion. Has been described.
In the film exterior battery described in Patent Document 1-3, when the film exterior battery expands due to an increase in internal pressure, a portion of the heat-sealed exterior film having a through hole is first peeled off to provide a venting mechanism. Acts as an (open valve).

In Patent Document 4, a safety valve member that softens and melts when the battery temperature rises is provided on one side of the outer periphery of the film exterior battery, and the safety valve member deforms and opens when the battery temperature rises with the generation of gas to externalize the gas. It is stated that it will be discharged to.

Although the film exterior battery is not configured to have a vent mechanism, Patent Document 5 states that the path passing through the main surfaces of the front and back surfaces of the film exterior battery is constrained by a band-shaped restraining member to generate an exterior film due to gas generation. It is described that the position of the fixed portion that cleaves when the film is expanded can be controlled.

Japanese Unexamined Patent Publication No. 2005-203262 Japanese Unexamined Patent Publication No. 2010-238860 Japanese Unexamined Patent Publication No. 2011-1987742 Japanese Patent No. 4622019 Japanese Unexamined Patent Publication No. 2013-004260

In the film exterior batteries described in Patent Documents 1 and 2 described above, since it is necessary to provide a fixing portion in which the exterior film is heat-sealed so as to cover the periphery of the non-fused portion communicating with the inside, a through hole is provided. The vent mechanism including the vent mechanism has a shape protruding from the outer circumference. Therefore, the configurations described in Patent Documents 1 and 2 may be difficult to adopt in electrical equipment that requires more miniaturization.

On the other hand, the film exterior batteries described in Patent Documents 3 and 4 are described in Patent Documents 1 and 2 because they have a configuration in which a through hole and a safety valve member that softens and melts when the battery temperature rises are provided in the fixed portion of the outer peripheral portion. It is not necessary to provide a protruding portion as in the case of the above configuration. Further, the film exterior battery described in Patent Document 5 is not provided with a through hole which is a vent mechanism, a safety valve member, or the like. Therefore, the film exterior battery described in Patent Document 3-5 can be downsized as compared with the configurations described in Patent Documents 1 and 2.

However, in the configurations described in Patent Documents 3 and 4, the through hole and the safety valve member may not operate reliably as a vent mechanism depending on their positions. Further, the film exterior battery described in Patent Document 5 can control the opening position when the exterior film is expanded to some extent, but cannot reliably open the film at the intended position.

The present invention has been made to solve the problems of the background technology as described above, and provides a film exterior battery capable of more reliably releasing gas at a intended position during expansion while enabling miniaturization. The purpose is to provide.

In order to achieve the above object, the film exterior battery of the present invention
The battery body with the exterior film as the exterior body and
Two external terminals consisting of a positive electrode terminal and a negative electrode terminal drawn from one short side of the battery body, respectively,
A band-shaped fixing band that restrains the battery body in a direction parallel to the short side so as to divide the long side of the battery body,
Have,
The fixed band has a width required for the short side of the battery body to be the long side of the region divided by the fixed band.
Wherein said outer film provided on the outer periphery of the cell body to the short side of the battery body of the fixing portions for sealing, release valve for releasing the gas generated within the battery body is provided et al is,
The release valve is provided between the external terminals, and is provided at a second fixing portion including a through hole, which is provided inside the first fixing portion which is the fixing portion provided on the outer periphery of the battery body. It is configured.

According to the present invention, it is possible to obtain a film exterior battery capable of more reliably releasing gas at a intended position during expansion while enabling miniaturization.

It is a top view which shows one structural example of the film exterior battery of 1st Embodiment. It is a top view which shows one structural example of the film exterior battery of 2nd Embodiment. It is a top view which shows one structural example of the film exterior battery of 3rd Embodiment. It is a top view which shows one structural example of the film exterior battery of 4th Embodiment. It is a top view which shows one structural example of the film exterior battery of 5th Embodiment. It is a top view which shows one structural example of the film exterior battery of 6th Embodiment. It is a top view which shows one structural example of the film exterior battery of 7th Embodiment. It is a top view which shows one structural example of the open valve suitable for the film exterior battery of this invention. It is a top view which shows the other structural example of the open valve suitable for the film exterior battery of this invention.

Next, the present invention will be described with reference to the drawings.

(First Embodiment)
FIG. 1 is a plan view showing a configuration example of the film exterior battery of the first embodiment.
As shown in FIG. 1, the film exterior battery of the first embodiment includes a battery main body 1 and two external terminals 2 including a positive electrode terminal and a negative electrode terminal, and the external terminal 2 is one of the battery main bodies 1. It is a configuration drawn from each short side.

In the battery body 1, a sheet-shaped positive electrode and a negative electrode (not shown) are laminated or wound with a separator (not shown) in between, and are sealed together with an electrolytic solution inside an exterior film 11 which is an exterior body. It is a composition. The outer circumference of the battery body 1 is sealed by heat-sealing two exterior films 11 to each other, and the vent mechanism is formed on one long side of the heat-sealed portion (fixed portion 12). An open valve 13 is provided. The release valve 13 is formed, for example, by providing a through hole in the fixing portion 12. The through hole may be provided only in one of the exterior films 11. FIG. 1 shows a configuration example in which the release valve 13 is provided at the substantially central portion of one long side of the battery body 1, but the position of the release valve 13 does not have to be at the substantially central portion and is from the central portion. It may be in a misaligned position.

In such a configuration, when the film exterior battery shown in FIG. 1 is excessively charged or discharged, or when gas is generated inside the battery body 1 due to a temporary high temperature, etc., the battery body 1 is described above. The exterior film 11 of the above expands.

Here, in the film exterior battery shown in FIG. 1, when the battery body 1 is expanded, it expands at a substantially central portion of the long side of the battery body 1 until the cross-sectional shape parallel to the short side becomes a perfect circle. That is, when the battery body 1 is expanded, the amount of expansion depends on the length of the short side. At this time, on the outer circumference of the battery body 1, a strong peeling stress is generated on the exterior film 11 on the long side side rather than the short side side, and the strongest pulling is particularly strong at the substantially central portion of the long side where the cross-sectional shape becomes a perfect circle. Peeling stress is generated. Therefore, if the release valve 13 is provided on the long side of the battery body 1, the release valve 13 is peeled off at a relatively low internal pressure when the battery body 1 expands, and gas is released. In particular, if the release valve 13 is provided at substantially the center of the long side of the battery body 1, gas can be released from the release valve 13 at a lower internal pressure. The internal pressure of the battery body 1 from which the release valve 13 is peeled off and the gas is released is hereinafter referred to as "open pressure".

According to the film exterior battery of the present embodiment, since the release valve 13 is provided at the fixing portion 12 on the outer periphery of the battery body 1, it is necessary to provide a protruding portion as in the configuration described in Patent Documents 1 and 2 described above. There is no. Therefore, while enabling miniaturization, it is possible to more reliably release the gas at the position where the release valve 13 is provided, that is, at the intended position during expansion.

(Second Embodiment)
FIG. 2 is a plan view showing a configuration example of the film exterior battery of the second embodiment.
As shown in FIG. 2, the film exterior battery of the second embodiment has one short side of the fixed portion 12 on the outer periphery of the battery body 1 sealed by heat fusion or the like (external terminal 2 in FIG. 2). An open valve 13 is provided between the two. Further, the film exterior battery of the second embodiment includes a band-shaped fixing band 3 that restrains the battery body 1 in a direction parallel to the short side so as to divide the long side of the battery body 1 into two. It is a configuration. The fixed band 3 is set to a width required for the short side of the battery body 1 to be the long side of the region divided by the fixed band 3. For the fixing band 3, for example, a heat-resistant synthetic resin band or a metal band may be used. Since other configurations are the same as those of the film exterior battery of the first embodiment shown in FIG. 1, the description thereof will be omitted.

As described above, in the film exterior battery of the first embodiment, when the battery body 1 is expanded, until the cross-sectional shape parallel to the short side becomes a perfect circle at the substantially central portion of the long side of the battery body 1. Inflate. Generally, the film exterior battery is used by being housed in a required housing. Therefore, when the housing is made of a plastic synthetic resin or the like, when the film exterior battery expands, the housing is expanded accordingly. It may be damaged.

Therefore, in the second embodiment, as shown in FIG. 2, the battery body is restrained by using the band-shaped fixing band 3 to suppress the expansion amount of the battery body. At this time, since the short side of the battery body 1 is a long side for the region divided by the fixed band 3, the short side of the battery body 1 can be treated as a pseudo long side. Therefore, in the second embodiment, the release valve 13 is provided on the short side of the battery body 1 (between the external terminals 2 in the example shown in FIG. 2).

When the battery body 1 is restrained by the fixed band 3, the amount of expansion of the battery body 1 is suppressed when the battery body 1 expands. Therefore, the peeling stress on the exterior film 11 is compared with that of the film exterior battery of the first embodiment. Decreases. Therefore, the film exterior battery of the second embodiment has a slightly higher opening pressure (difficult to empty) than the film exterior battery of the first embodiment. According to the experiment of the applicant, it has been confirmed that the film exterior battery of the second embodiment has an open pressure increase of about 10% as compared with the film exterior battery of the first embodiment.
Therefore, the configuration shown in the second embodiment can be adopted when it is desired to set the gas discharge direction to the short side side of the battery body 1 or when it is necessary to protect the housing when the film exterior battery expands. Good.

According to the second embodiment, the same effect as that of the first embodiment can be obtained, and the housing for accommodating the film exterior battery can be prevented from being damaged due to the expansion of the film exterior battery.

(Third Embodiment)
FIG. 3 is a plan view showing a configuration example of the film exterior battery of the third embodiment.
As shown in FIG. 3, the film exterior battery of the third embodiment has an open valve in the vicinity of the extraction portion of one of the two external terminals 2 in the fixing portion 12 on the outer periphery of the battery body 1. 13 is provided. Since other configurations are the same as those of the film exterior battery of the second embodiment shown in FIG. 2, the description thereof will be omitted.

The film exterior battery of the third embodiment as shown in FIG. 3 can also obtain the same effect as the film exterior battery of the second embodiment.

As described above, in the film exterior battery, if the release valve 13 is provided at substantially the center of the long side of the battery body 1, gas can be discharged from the release valve at a lower internal pressure. Therefore, the film exterior battery of the third embodiment has a higher opening pressure than the film exterior battery of the second embodiment in which the release valve 13 is provided at substantially the center of the short side of the battery body 1.

However, according to the experiment of the applicant, the amount of increase in the opening pressure of the film exterior battery shown in FIG. 3 is small (about 30%) with respect to the opening pressure of the film exterior battery shown in FIG. Even if 13 is not located in the substantially central portion of the short side of the battery body 1, it does not pose a big problem in practical use.

(Fourth Embodiment)
FIG. 4 is a plan view showing a configuration example of the film exterior battery of the fourth embodiment.
As shown in FIG. 4, the film exterior battery of the fourth embodiment has a configuration in which an release valve 13 is provided in a substantially central portion of the other short side having no external terminal 2 in the fixing portion 12 on the outer periphery of the battery body 1. Is. Since other configurations are the same as those of the film exterior battery of the second embodiment shown in FIG. 2, the description thereof will be omitted.

The film exterior battery of the fourth embodiment as shown in FIG. 4 can also obtain the same effect as the film exterior battery of the second embodiment.

(Fifth Embodiment)
FIG. 5 is a plan view showing a configuration example of the film exterior battery of the fifth embodiment.
As shown in FIG. 5, in the film exterior battery of the fifth embodiment, an open valve 13 is provided on one long side of one of the fixing portions 12 on the outer periphery of the battery body 1 to divide the short side of the battery body 1. As described above, the battery body 1 is configured to have a band-shaped fixing band that restrains the battery body 1 in a direction parallel to its long side.

The film exterior battery of the fifth embodiment as shown in FIG. 5 can also obtain the same effect as the film exterior battery of the second embodiment.

In the film exterior battery of the fifth embodiment, as shown in FIG. 5, the fixed band 3 restrains the long side direction of the battery body 1, so that the film exterior of the second to fourth embodiments is shown. The fixed band 3 is longer than the battery. Therefore, the cost of the fixed band 3 increases as compared with the second to fourth embodiments.

Further, in the film exterior battery of the fifth embodiment, the length of the short side of the region divided by the fixed band 3 is shorter than that of the film exterior battery shown in the second to fourth embodiments. .. As described above, in the film exterior battery, when the battery body 1 is expanded, the amount of expansion depends on the length of the short side. Therefore, the shorter the length of the short side with respect to the long side, the smaller the amount of expansion, and the longer side The peeling stress acting on the exterior films 11 on the side is reduced. That is, as shown in FIG. 5, when the length in the short side direction of the region divided by the fixed band 3 is A and the length in the long side direction is B, the smaller the value of A / B is, the more the opening pressure is. Will be higher. Therefore, the film exterior battery of the fifth embodiment has a higher opening pressure than the film exterior battery shown in the second to fourth embodiments.

Therefore, the configuration shown in the fifth embodiment is adopted when it is necessary to set the gas discharge direction to the long side side of the battery body 1 and it is necessary to protect the housing when the film exterior battery is expanded. do it.

(Sixth Embodiment)
FIG. 6 is a plan view showing a configuration example of the film exterior battery of the sixth embodiment.
As shown in FIG. 6, the film exterior battery of the sixth embodiment is a battery in which an open valve is provided on one short side (between the external terminals 2 in FIG. 6) of the fixed portions 12 on the outer periphery of the battery body 1. The battery main body 1 is restrained by using two band-shaped fixing bands 3 in a direction parallel to the short side thereof so as to divide the long side of the main body 1 into three parts. The number of the fixed bands 3 is not limited to two, and may be three or more.

The film exterior battery of the sixth embodiment as shown in FIG. 6 can also obtain the same effect as the film exterior battery of the second embodiment.

Since the film exterior battery of the sixth embodiment uses a plurality of fixed bands 3, the cost of the fixed bands 3 increases as compared with the second to fourth embodiments.

Further, by restraining the battery body 1 with a plurality of fixed bands 3, as shown in FIG. 6, in the region including the release valve 13 divided by the fixed bands 3, the film of the fifth embodiment. As with the external battery, the A / B value becomes smaller. Therefore, the film exterior battery of the sixth embodiment has a higher opening pressure than the film exterior battery shown in the second to fourth embodiments.

Therefore, in the configuration shown in the sixth embodiment, for example, the long side of the battery body 1 is long, and in one fixed band 3, the short side of the battery body 1 is divided by the fixed band 3. It may be adopted when it does not become the long side of.

(7th Embodiment)
FIG. 7 is a plan view showing a configuration example of the film exterior battery of the seventh embodiment.
As shown in FIG. 7, in the film exterior battery of the seventh embodiment, the width of the fixing band 3 for restraining the battery body 1 is fixed to be provided in the film exterior battery shown in the second to sixth embodiments. The configuration is wider than the width of the band 3. FIG. 7 shows an example using a fixed band 3 having a width approximately twice that of the fixed band 3 of the second embodiment shown in FIG. Since other configurations are the same as those of the film exterior battery of the second embodiment shown in FIG. 2, the description thereof will be omitted.

The film exterior battery of the seventh embodiment as shown in FIG. 7 can also obtain the same effect as the film exterior battery of the second embodiment.

Since the film exterior battery of the seventh embodiment uses the wide fixed band 3, the cost of the fixed band 3 increases as compared with the second to fourth embodiments.
Further, by restraining the battery body 1 with the wide fixed band 3, as shown in FIG. 7, in the region including the release valve 13 divided by the fixed band 3, the fifth and sixth implementations are performed. The A / B value becomes smaller as in the case of the film exterior battery of the above form. Therefore, the film exterior battery of the seventh embodiment has a higher opening pressure than the film exterior battery shown in the second to fourth embodiments.

Therefore, in the configuration shown in the seventh embodiment, for example, the long side of the battery body 1 is long and the short side of the battery body 1 in the narrow fixed band 3 is the same as in the sixth embodiment. May be adopted when is not the long side of the region divided by the fixed band 3.

(8th Embodiment)
In the eighth embodiment, a shape of an open valve capable of releasing gas at a lower internal pressure of the battery body 1 is proposed. The shape of the open valve shown in the eighth embodiment can be applied to any of the film exterior batteries shown in the first to seventh embodiments.
FIG. 8A is a plan view showing a configuration example of an open valve suitable for the film exterior battery of the present invention, and FIG. 8B is a plan view showing another configuration example of the open valve suitable for the film exterior battery of the present invention. .. 8A and 8B show an example in which an open valve is provided on the short side side (between the external terminals 2) of the battery body 1.

The release valve 13A shown in FIG. 8A is further provided with a fixing portion (second fixing portion) 12B serving as the release valve 13A inside the fixing portion (first fixing portion) 12A on the outer periphery of the battery body 1, and the second The fixing portion 12B is provided with a through hole. The width of the second fixing portion 12B in the short side direction of the battery body 1 is set to a value slightly larger than the diameter of the through hole.

In such a configuration, when the battery body 1 is expanded, peeling stress acts from three directions of the second fixing portion 12B that does not come into contact with the first fixing portion 12A. Therefore, the opening valve 13A is peeled off at a lower internal pressure than the opening valve 13 having a through hole in the first fixing portion 12A, and gas is released. The width of the second fixing portion 12B has an effect that the opening valve 13A is more easily peeled off when the width is closer to the diameter of the through hole.

The release valve 13B shown in FIG. 8B is provided with a fixing portion (second fixing portion) 12B serving as the release valve 13B inside the fixing portion (first fixing portion) 12A on the outer periphery of the battery body 1, and the second fixing portion is provided. The structure is such that a through hole is provided in the portion 12B. Further, in the release valve 13B shown in FIG. 8B, a concave portion is provided in the first fixing portion 12A, and a second fixing portion 12B is provided in the recess of the concave portion. The recessed width of the concave portion is longer than the width of the second fixing portion 12B.

In such a configuration, when the battery body 1 is expanded, peeling stress acts from three directions of the second fixing portion 12B that does not come into contact with the first fixing portion 12A, similarly to the opening valve 13A shown in FIG. 8A. .. Further, in the open valve 13B shown in FIG. 8B, the peeling stress acting on the second fixing portion 12B from the direction parallel to the first fixing portion 12A becomes stronger. Therefore, the opening valve 13B is peeled off at a lower internal pressure than the opening valve 13 having a through hole in the first fixing portion 12A, and gas is released.

As described above, in the film exterior battery, the positive electrode and the negative electrode (not shown) and the external terminal 2 enclosed in the exterior film 11 are connected via electrode lead-out tabs, respectively. Since the space between these two electrode extraction tabs is usually not effectively utilized, an open valve (second fixing portion) is provided between the external terminals 2 (between the electrode extraction tabs) as shown in FIGS. 8A and 8B. ) Even if 13A and B are provided, it is not necessary to change the size of the entire film exterior battery. In the first to eighth embodiments, two external terminals 2 are drawn out from one short side of the battery body 1, respectively, but two external terminals 2 are drawn from one long side of the battery body 1. The same applies to the configuration in which each of the terminals 2 is pulled out.

On the other hand, when the release valves 13A and B are provided on the long side and the short side of the battery body 1 without the external terminal 2, the second fixing portion 12B is provided inside the fixing portion (first fixing portion) 12A on the outer periphery of the battery body 1. Therefore, it is necessary to lengthen the length of the long side or the short side of the film exterior battery according to the size of the second fixing portion 12B.
Therefore, the shapes of the open valves 13A and B shown in the eighth embodiment can be applied to the film exterior batteries shown in the first, third to fifth embodiments, but between the external terminals 2. It is more preferable to apply it to the film exterior battery shown in the second, sixth and seventh embodiments in which the release valve is provided.

1 Battery body 2 External terminal 3 Fixed band 11 Exterior film 12 Fixed part 12A First fixed part 12B Second fixed part 13, 13A, 13B Open valve

Claims (4)

The battery body with the exterior film as the exterior body and
Two external terminals consisting of a positive electrode terminal and a negative electrode terminal drawn from one short side of the battery body, respectively,
A band-shaped fixing band that restrains the battery body in a direction parallel to the short side so as to divide the long side of the battery body,
Have,
The fixed band has a width required for the short side of the battery body to be the long side of the region divided by the fixed band.
An open valve for releasing the gas generated in the battery body is provided on the short side of the battery body among the fixing portions for sealing the exterior film provided on the outer periphery of the battery body.
The release valve is provided between the external terminals, and is provided at a second fixing portion including a through hole, which is provided inside the first fixing portion which is the fixing portion provided on the outer periphery of the battery body. Constructed film exterior battery. The open valve, film covered battery according to claim 1 positioned at a substantially central portion of the side to which the relief valve is provided. The film exterior battery according to claim 1 or 2 , wherein the release valve is formed of a through hole formed in the exterior film of at least one of the fixing portions. The first fixing portion is provided with a concave portion.
The second fixing portion is provided in the recess of the concave portion, and the second fixing portion is provided.
The film exterior battery according to claim 1 , wherein the concave width of the concave portion is longer than the width of the second fixing portion.

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