JP2002324536A - Sealed cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed cell which can respond a small changes of an internal pressure of a package. SOLUTION: A safety valve 30 of the sealed cell 10 is provided with an oval-shaped communicating hole 31 to communicate a metal resin composite film 21 to a thickness direction and an oval-shaped lid member 32 to shut the communicating hole 31 and to be fused on the surface of the metal resin composite film 21 as it is laminated, the communicating hole 31 is arranged at least on a side face along a horizontal direction in a housing portion 23, and the lid member 32 operates prior to fusion spaces 24, 25 and 26 when the internal pressure of the package for the cell reaches more than a regulated value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed battery,
In particular, the present invention relates to a sealed battery in which a power generation element is housed in a housing portion of the sealed battery package and a margin for fusion is provided on a periphery of the sealed battery package.

[0002]

2. Description of the Related Art In recent years, with the great progress of electronic technology, portable electronic devices for general users have been reduced in size and weight. Since the demand for smaller and lighter batteries is increasing, sealed batteries are often used. In general, a sealed battery is one in which a power generating element including a metal foil serving as a negative electrode and a positive electrode is formed via a separator, and the power generating element is housed and sealed in a metal battery case formed in a square shape or the like. .

When the power generating element is housed and sealed in such a battery case, the power generating element is housed in a bottomed rectangular cylindrical battery case body, and then a negative electrode lead and a positive electrode lead attached to the power generating element are joined. The opening of the battery case main body is closed by the lid member, and the opening edge of the battery case main body and the peripheral edge of the lid member are joined by welding or the like.

[0004] The sealed battery is provided with a safety valve. When the internal pressure of the battery case body rises excessively due to overcharging or the like, the safety valve prevents a part of the battery case body from breaking due to the internal pressure, thereby preventing the battery case body from expanding and bursting.

[0005]

In recent years, as a portable electronic device, a sealed battery in which a power generation element is housed in a sealed battery package formed of a metal-resin composite film is frequently used. However, in such a sealed battery, when the internal pressure of the sealed battery package changes minutely, the sealed battery package may expand and press on the portable electronic device. It requires a safety valve that operates with changes in internal pressure. That is,
When the internal pressure of the sealed battery package changes minutely, such a safety valve of the sealed battery operates in response to the change before the sealed battery package starts to expand. More reliably prevent the package from expanding and bursting. For this reason, there has been a demand for the practical use of a safety valve that responds to minute changes in the internal pressure of a sealed battery package.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a sealed battery capable of responding to a minute change in the internal pressure of a sealed battery package.

[0007]

SUMMARY OF THE INVENTION The present invention provides a separator,
A flat power generating element having a negative electrode and a positive electrode, a sealed battery package for housing and sealing the power generating element in a housing formed in a metal-resin composite film, and the sealed battery so as to surround the power generating element And a safety valve provided on the sealed battery package so as to be activated when the internal pressure of the housing reaches a certain level or more. It is a sealed battery.

By the way, the force F applied to the metal-resin composite film when the internal pressure of the housing reaches a certain level or more is derived from the following equation based on the area S and the change ΔP in the internal pressure. F = ΔP × S

That is, in the sealed battery, it is advantageous to set the area S large for the safety valve that operates in response to the minute internal pressure change ΔP in the housing. Therefore, according to the present invention, as described in claim 1, the safety valve includes a through hole that penetrates the metal-resin composite film in a thickness direction, a through-hole closed, and a surface of the metal-resin composite film. A lid member fused so as to be stacked, wherein the through-hole is provided on at least one surface along the flat direction in the housing portion, and the internal pressure of the sealed battery package has reached a certain value or more. It is characterized in that the lid member is sometimes operable earlier than the fusion allowance.

Here, as a structure for operating the cover member earlier than the fusion allowance, for example, at least a part of the width dimension of the cover member fusion allowance for fusing the metal resin composite film and the cover member is set. A structure in which the peel strength is intentionally reduced by setting the width smaller than the width of the fusion allowance, or a structure in which the position corresponding to the through hole in the lid member is substantially thinned can be adopted.

In the thus-configured sealed battery, a through-hole is formed in the metal-resin composite film, and the through-hole is closed with a lid member to constitute a safety valve. When the temperature exceeds a certain level, it is activated earlier than the fusion allowance. In this manner, the safety valve can operate in response to a minute change in the internal pressure, so that the housing can be reliably prevented from expanding due to the internal pressure of the sealed battery package.

Further, in the present invention, at least a part of the width of the cover member fusing margin for fusing the metal-resin composite film to the cover member has a width dimension as described in claim 2.
It is characterized in that it is set smaller than the width dimension of the fusion allowance. Since the width of at least a part of the lid member fusion allowance is set smaller than the width of the fusion allowance, when the internal pressure of the sealed battery package reaches a certain level or more, the safety valve is provided earlier than the fusion allowance. It can be operated reliably.

Further, in the present invention, as described in claim 3, the position corresponding to the through hole in the lid member is substantially thinned. Therefore, when the internal pressure of the package for a sealed battery reaches a certain level or more, the portion thinned earlier than the fusion allowance is displaced upward by the internal pressure and breaks. For this reason, it is possible to prevent the internal pressure of the sealed battery package from being released and prevent the housing portion from expanding.

Further, in the present invention, as described in claim 4, a concave portion is provided on a surface of the lid member. Therefore, when the internal pressure of the sealed battery package reaches a certain level or more, the recessed portion is formed earlier than the fusion allowance, and the thinned portion is displaced upward by the internal pressure and breaks. For this reason, it is possible to prevent the internal pressure of the sealed battery package from being released and prevent the housing portion from expanding. In addition, by providing the concave portion on the surface of the lid member, a thinned portion can be easily formed, so that the cost can be reduced.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. In each of the embodiments described below, the members and the like already described in FIG. 1 are denoted by the same reference numerals or corresponding reference numerals in the drawings to simplify or omit the description.

As shown in FIG. 1, a sealed battery 10 according to a first embodiment of the present invention includes a negative electrode and a metal foil serving as a positive electrode via a separator, and includes a positive terminal 12 and a negative terminal 13. Power generating element 11 having a flattened shape, and a housing 23 formed of the power generating element 11 in a metal-resin composite film 21.
Sealed battery package 20 housed and sealed in
A welding allowance 24, 25, 26 having a predetermined width dimension W1 provided on the periphery of the sealed battery package 20 so as to surround the battery pack 11, and an operation when the internal pressure of the housing portion 23 reaches a certain level or more. A safety valve 30 provided in the sealed battery package 20.

A power generation element is provided by the sealed battery package 20.
When accommodating and sealing the housing 11, a hollow (housing 23) corresponding to the shape of the power generating element 11 is formed in advance in the center of the metal-resin composite film 21 having a rectangular shape. After the power generation element 11 is arranged in the center, the metal-resin composite film 21 is bent at the center 22 and overlapped, and the power-generation element 11 is sandwiched between the metal-resin composite films 21. Next, the heat-fusible resin layers are fused together while heating the three sides of the superposed metal-resin composite film 21 to form fusion margins 24, 25, and 26.

As shown in FIG. 2, the metal-resin composite film 21 includes, as an example, a metal foil core 21A made of aluminum foil;
A fusible resin layer 21B made of resin along the front surface of the metal foil core 21A and a fusible resin layer 21C made of resin along the back surface of the metal core 21A are laminated. Is often used.

As shown in FIG. 1, the safety valve 30 has an elliptical through hole 31 penetrating the metal-resin composite film 21 in the thickness direction.
And an oval lid member 32 that is fused so as to be stacked on the surface of the metal-resin composite film 21 while closing the through-hole 31, and the through-hole 31 is at least along the flat direction in the accommodation portion 23. The lid member 32 is provided on one side, and is configured such that when the internal pressure of the sealed battery package 20 reaches a certain level or more, the lid member 32 operates before the fusion allowances 24, 25, and 26.

As shown in FIG. 2, the lid member 32 includes, as an example, a metal foil core 32A made of aluminum and a metal foil core 32A.
Adhesive Resin Layer with Resin Metal Adhesion Along Surface
What laminated | stacked 32B and the resin-fusible resin layer 32C which has resin adhesiveness made of resin along the back surface of the metal foil core material 32A is often used. The metal foil core material 32A, the fusible resin layer 32B and the fusible resin layer 32C are made of the same material as the metal foil core material 21A, the fusible resin layer 32B and the fusible resin layer 21C, respectively.

As shown in FIGS. 2 and 3, the safety valve 30
The cover member fusion margin 33 (the mesh-like region in FIG. 3) for fusing the metal-resin composite film 21 and the cover member 32 is
32A, a portion 33 of the lid member fusion allowance 33
The width W2 of A is set smaller than the widths W3 and W4 of the other lid member fusion margins 33B and 33C. further,
The width W3 and W4 of the lid member fusion allowance 33B and 33C are the fusion allowance 2
4, 25 and 26 are set smaller than the width dimension W1.
The widths W3 and W4 of the cover member fusion margins 33B and 33C may be the same.

Therefore, when the internal pressure of the accommodating portion 23 of the sealed battery package 20 reaches a certain level or more, the safety valve 30 is surely operated before the fusion allowances 24, 25 and 26 of the metal-resin composite film 21. be able to. For this reason, it becomes possible to operate the safety valve 30 in response to a minute change in the internal pressure in the housing portion 23. With the internal pressure of the sealed battery package 20
Can reliably be prevented from expanding. Therefore, the accommodation section 23
Can prevent the electronic device from being adversely affected by the expansion of the electronic device.
In particular, since the lid member fusion margin 33 is along the peripheral edge 32A of the lid member 32, the internal pressure of the sealed battery package 20 also acts between the lid member 32 and the vicinity of the peripheral edge 31A of the through hole 31. That is, when the internal pressure of the sealed battery package 20 is received in a large area of the lid member 32, the safety valve 30 operates in response to a minute internal pressure change in the housing portion 23.

Here, the force applied to the lid member 32 is represented by F,
Assuming that the area of 31 is S and the change in internal pressure is ΔP, F = ΔP ×
S. Therefore, in order to operate the safety valve 30 in response to the small internal pressure change ΔP in the housing portion 23, it is advantageous to set the area S of the through hole 31 large. Therefore, the through hole 31, that is, the safety valve 30 is connected to the sealed battery package 20.
It is difficult to form the safety valve 30 on the upper surface (first embodiment) or the lower surface of the sealed battery package 20.

Some sealed batteries use a flexible metal-resin composite film as an outer package. In such a sealed battery, the metal-resin composite film expands due to a weak internal pressure. For this reason, this sealed battery
Although a safety valve that operates at a low internal pressure is required, the safety valve of the present invention can satisfy the requirement.

It is to be noted that the safety valve 30 is provided with a sealed battery package.
Another reason for forming the upper surface (first embodiment) or the lower surface of the package 20 is that there is a fusion allowance on the side surface of the sealed battery package 20, and this fusion allowance is folded along the side surface. In this case, it is difficult to operate the safety valve 30. In addition, since the side surface of the sealed battery package 20 is narrow, providing the safety valve 30 on the side surface requires accuracy during processing, but the accuracy is required during processing because the upper and lower surfaces of the sealed battery package 20 are wide. And not. For this reason, manufacture of a sealed battery becomes easy.

Further, as shown in FIG. 2, a lid member 32 is laminated on the surface of the metal-resin composite film 21 so that the lid member 32 projects from the metal-resin composite film 21 to form a convex step. Therefore, as shown in FIG. 4A, normally, the sealed battery package 20 is in a state where only the lid member 32 is in contact with the inner wall 36 of the electronic device body 35, and the sealed battery package 20 is A gap is formed between the electronic device main body 35 and the inner wall 36. For this reason, if the safety valve 30 does not operate even if the internal pressure rise of the sealed battery package 20 reaches a certain level or more, as shown in FIG. The sealed battery package 20 expands until the space between itself and the inner wall 36 is filled.

Therefore, according to the sealed battery 10, even if the safety valve 30 does not operate, the sealed battery package 20 does not press the entire inner wall 36 of the electronic device body 35, and Countermeasures to prevent adverse effects are being duplicated. On the other hand, in the conventional sealed battery, when the housing portion expands due to the internal pressure, the entire housing portion presses the inner wall 36 of the electronic device main body 35, which may adversely affect the electronic device.

By the way, if the expansion of the sealed battery package 20 in the vertical direction is suppressed, the sealed battery package 20 may expand to the side, but the fusion margin is folded along the side. If so, the fusion allowance serves as a cushioning material, so that it is possible to prevent the electronic device from being adversely affected.

Next, second to fourth embodiments of the sealed battery will be described with reference to FIGS. As shown in FIGS. 5 and 6, in a sealed battery 40 according to the second embodiment of the present invention, a safety valve 41 is formed by a through hole 31 and a lid member 42, and a surface 42 A of the lid member 42 (that is, a lid 42). Member 42
Are formed in the fusible resin layer).

By providing the concave portion 43 on the surface 42A of the lid member 42, the position corresponding to the through hole 31 in the lid member 42 is substantially equal to the thin film portion 44 having a thickness t2 smaller than the thickness t1 of the lid member 42.
(See FIG. 6). By providing the concave portion 43 on the surface 42A of the lid member 42, the thin film portion 44 can be easily formed, so that the cost can be reduced.

According to the sealed battery 40 of the second embodiment, the same effect as the sealed battery 10 of the first embodiment can be obtained. In addition, as shown in FIG.
Even if the surface 42A of the lid member 42 is in close contact with the inner wall 36 of the electronic device 35, the recess 43 secures a gap with the inner wall 36 of the electronic device main body 35. When the internal pressure (indicated by an arrow) reaches a certain level or more, the thin film portion 44 is displaced upward by the internal pressure and breaks as shown in FIG. 7B. For this reason, it is possible to prevent the internal pressure of the storage section 23 from being released and the storage section 23 from expanding.

As a modification of the second embodiment, it is conceivable to provide a concave portion on the back surface of the lid member 42. By molding the periphery of the concave portion larger than the periphery of the through-hole, the width dimension of the lid member fusion margin is set smaller than the width dimension W1 of the fusion margins 24, 25, 26 (see FIG. 1). Thereby, the same effect as in the first embodiment can be obtained.

As shown in FIG. 8, the sealed battery 50 according to the third embodiment of the present invention is different from the first embodiment in that the metal member composite film 21 and the cover member 32 are replaced with the cover member fusion allowance 33 of the first embodiment. Is set to a constant width dimension W5, and the width dimension W5 of the lid member fusion margin 53 is set to the width dimension W of the fusion margins 24, 25, 26.
1 (see FIG. 1). Third
The same effect as in the first embodiment can be obtained also in the sealed battery 50 of the embodiment.

The sealed battery according to the first embodiment described above.
10 is a cover member fusion allowance 33 (the mesh-like area in FIG. 3) is a cover member.
Although provided along the periphery 32A of 32, the present invention
As in the sealed battery 60 of the fourth embodiment shown in FIG. 7, the lid member fusion allowance 63 may be provided near the peripheral edge 31A of the through hole 31. According to such a sealed battery 60, the same effects as in the first embodiment can be obtained, and the molten resin extruded from the lid member fusion allowance 63 is not exposed to the outside, so that good appearance can be obtained. .

In the above-described embodiment, an example in which the lid members 32 and 42 are formed in an elliptical shape has been described. However, the present invention is not limited to this. For example, the lid member may be formed in a rectangular shape, and further in a circular shape. It may be formed. Further, in the second embodiment, an example was described in which the thin film portion 44 was substantially formed by providing the concave portion 43 on the surface 42A (fusible resin layer) of the lid member 42. However, the present invention is not limited to this. Similar effects can be obtained by forming slits on both surfaces (fusible resin layer) of the front and back surfaces of the member. The slit may be formed only on one surface (fusible resin layer) on the front surface or the back surface of the lid member.

In addition, in the above-described embodiment, an example has been described in which the through-hole 31 is provided on at least one surface of the housing portion 23 along the flat direction, but the present invention is not limited to this.
May be provided on both sides. Furthermore, the present invention is not limited to each of the above-described embodiments, and can be appropriately modified and improved. The power generating element, the positive electrode terminal, the negative electrode terminal, and the sealed battery illustrated in each of the above-described embodiments. The material, shape, dimensions, form, number, location, thickness, and the like of the package for use and the metal-resin composite film are arbitrary and are not limited as long as the present invention can be achieved.

[0037]

As described above, according to the present invention, as described in claim 1, a through-hole is opened in the metal-resin composite film, and the through-hole is closed with a lid member to constitute a safety valve. When the internal pressure of the sealed battery package reaches a certain level or more, the safety valve is operated earlier than the fusion allowance. As described above, the safety valve can be operated in response to a minute change in the internal pressure, so that the housing can be reliably prevented from being expanded by the internal pressure of the sealed battery package. Therefore, it is possible to prevent the electronic device from being adversely affected by the expansion of the housing portion.

Further, according to the present invention, as described in claim 2, at least a part of the width of the cover member fusing margin is set smaller than the width of the fusing margin. When the internal pressure of the package reaches a certain level or more, the safety valve can be reliably operated earlier than the fusion allowance. Therefore, the safety valve can be operated in response to a minute change in the internal pressure.

According to the present invention, the position corresponding to the through hole in the lid member is substantially reduced in thickness. For this reason, when the internal pressure of the sealed battery package reaches a certain level or more, the portion thinned earlier than the fusion allowance shifts upward due to the internal pressure and breaks. For this reason, it is possible to prevent the internal pressure from escaping due to the release of the internal pressure,
The electronic device can be prevented from being adversely affected.

Further, according to the present invention, as described in claim 4, a concave portion is provided on the surface of the lid member. Therefore, when the internal pressure of the sealed battery package reaches a certain level or more,
By forming the concave portion earlier than the fusion allowance, the thinned portion is displaced upward by internal pressure and breaks. For this reason, it is possible to prevent the internal pressure from being released, thereby preventing the housing portion from expanding, thereby preventing the electronic device from being adversely affected. By providing the concave portion on the surface of the lid member, a thinned portion can be easily formed, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a sealed battery according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a plan view showing a main part of the first embodiment according to the present invention.

FIG. 4 is a cross-sectional view illustrating the operation of the first embodiment according to the present invention.

FIG. 5 is an exploded perspective view showing a second embodiment of the sealed battery according to the present invention.

FIG. 6 is a sectional view showing a main part of a second embodiment according to the present invention.

FIG. 7 is a sectional view showing the operation of the second embodiment according to the present invention.

FIG. 8 is a sectional view showing a third embodiment of the sealed battery according to the present invention.

FIG. 9 is a sectional view showing a fourth embodiment of the sealed battery according to the present invention.

[Explanation of symbols]

 10, 40, 50, 60 Sealed battery 11 Power generation element 20 Package for sealed battery 21 Metal-resin composite film 23 Housing 24, 25, 26 Fusing allowance 30, 41 Safety valve 31 Through hole 32, 42 Cover member 33 Cover member Fusion margin 33A At least a part of lid fusion margin 42A Surface of lid 43 Concavity

Claims (4)

[Claims] 1. A flat power generating element having a separator, a negative electrode and a positive electrode, a sealed battery package for housing and sealing the power generating element in a housing formed in a metal-resin composite film, A fusion allowance having a predetermined width dimension provided on a peripheral edge of the sealed battery package so as to surround the package, and provided on the sealed battery package so as to operate when the internal pressure of the housing reaches a certain level or more. A sealed valve provided with a safety valve, wherein the safety valve has a through hole penetrating the metal-resin composite film in the thickness direction, and closes the through-hole and is laminated on the surface of the metal-resin composite film. The through hole is provided on at least one surface along the flat direction of the housing portion, and A sealed battery, wherein the lid member is operable before the fusion allowance when the internal pressure reaches a certain level or more. 2. A width dimension of at least a part of a margin for fusing a lid member for fusing the metal-resin composite film and the lid member is set to be smaller than a width dimension of the fusion margin. The sealed battery according to claim 1. 3. The sealed battery according to claim 1, wherein a position of the cover member corresponding to the through hole is substantially thinned. 4. The sealed battery according to claim 3, wherein a concave portion is provided on a surface of the lid member.