The present invention relates to a power storage device.
Conventionally, power storage devices are known as power sources for various electronic devices. For example, Patent Document 1 describes that a laminate in which electrode materials and separator materials are alternately laminated is sealed by thermocompression bonding with a laminator.
In a power storage device as described in Patent Document 1, the laminate is pressure bonded and sealed with the laminator. Therefore, it is necessary to form at a peripheral edge part of the laminate, a sealing part which has upper and lower laminate films sealed by pressure bonding. This may cause an energy density per unit area of the power storage device to be reduced.
A main object of the present invention is to provide a power storage device having a high energy density per unit area.
A power storage device according to the present invention includes a device body and a package. The device body includes a negative electrode, a positive electrode, and a separator. The separator is between the negative electrode and the positive electrode. The package has a shape corresponding to a shape of the device body and accommodates the device body therein. The package includes a first laminate film, a second laminate film, and a sealing material. The first laminate film is on a first side in a laminating direction of the device body. The second laminate film is on a second side in the laminating direction of the device body opposite the first side. The sealing material connects the first laminate film and the second laminate film on a side surface of the device body.
According to the present invention, the power storage device with the high energy density per unit area can be provided.
Hereinafter, examples of preferred embodiments which implement the present invention will be described. However, the following embodiments are illustrative only. The present invention is not limited to the following embodiments.
Moreover, in each of the drawings referred to in the embodiments and the like, members which substantially have the same function shall be referred to with the same reference symbol. The drawings referred to in the embodiments and the like are schematically described. A dimensional ratio of an object drawn in the drawings may be different from a ratio of dimensions of an actual object.
The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio and the like of the object should be determined in consideration of the following description.
The power storage device 1 shown in
As shown in
As shown in
As shown in
The package 3 includes a first laminate film 31 and a second laminate film 32.
The first and second laminate films 31 and 32 are not particularly limited as long as at least one main surface thereof is an insulating film. For example, the first and second laminate films 31 and 32 can respectively be constituted of a first resin layer positioned on a side of the device body 2, a metal foil provided on the first resin layer, and a second resin layer provided on the metal foil. The first resin layer can be made of, for example, a resin such as polypropylene. The metal foil is a member for reducing oxygen permeability and moisture permeability of the laminate film. The metal foil can be made of, for example, an aluminum foil or stainless steel foil. The second resin layer can be made of, for example, a resin such as polyethylene terephthalate (PET) or nylon (registered trademark). Note that the first and second laminate films 31 and 32 may be constituted of, for example, a laminate of the first resin layer and the metal foil.
The device body 2 is sealed with the first and second laminate films 31 and 32. The first laminate film 31 is positioned on one side in the laminating direction of the device body 2. On the other hand, the second laminate film 32 is positioned on the other side in the laminating direction of the device body 2. The first and second laminate films 31 and 32 have a larger area than the device body 2.
As shown in
The sealing material 4 is preferably made of insulating material having low oxygen permeability and moisture permeability. The sealing material 4 may be made of, for example, a resin such as polypropylene. Further, the sealing material 4 may be constituted of, for example, a laminate of first and second resin layers and a metal layer provided between the first resin layer and the second resin layer. In this case, the first and second resin layers can be made of, for example, polypropylene. The metal layer may be made of, for example, aluminum or stainless steel.
In the present embodiment, as shown in
Among the side surface of the device body 2, on the portion of the side surface from which the negative electrode terminal Ila and the positive electrode terminal 12a are not drawn, a peripheral edge part of the first laminate film 31 and a peripheral edge part of the second laminate film 32 are respectively connected to the sealing material 4. Specifically, in the present embodiment, the peripheral edge part of the first laminate film 31 and the peripheral edge part of the second laminate film 32 are respectively bonded to the sealing material 4.
Usually, in the power storage device as described in Patent Document 1, when the device body is sealed with the first and second laminate films, the device body is sealed by being sandwiched and pressure bonded by the first and second laminate films having a larger area than the device body. For this reason, a sealing part is required in which the first and second laminate films overlap without interposing the device body. Therefore, there exists a problem that the energy density per unit area of the power storage device is reduced.
In the power storage device 1, the sealing material 4 for connecting the first laminate film 31 and the second laminate film 32 is provided on the side surface of the device body 2. For this reason, the sealing part of the package 3 can be made small. Therefore, the power storage device 1 in plan view can be reduced in area. Therefore, the energy density per unit area of the power storage device 1 can be increased.
Further, in the power storage device 1, each of the first and second laminate films 31 and 32, and the sealing material 4 are bonded. Accordingly, on the side surface of the device body 2, a portion where the first and second laminate films 31 and 32 are connected are securely sealed by the sealing material 4, so that an electrolyte and the like are difficult to leak, and moisture, oxygen and the like are less likely to enter into the package 3.
From the viewpoint of further downsizing the power storage device 1, as shown in
From the same viewpoint, the sealing material 4 is preferably plate-shaped, sheet-shaped, or film-shaped.
In the power storage device 1, an end surface of the bent part of the first laminate film 31 and an end surface of the bent part of the second laminate film 32 are in contact with each other. Therefore, the sealing material 4 is covered with the bent parts, and the sealing material 4 is not substantially exposed. Therefore, the oxygen permeability and moisture permeability of a portion where the sealing material 4 is arranged are lower.
As shown in
Incidentally, when the adjacent bent parts of the laminate film are provided with a cut or notch, it is expected that oxygen and moisture easily enter into the power storage device from this cut or notched portion. However, in the power storage device 1 of the present embodiment, the sealing material 4 is provided across the cut or notch between the adjacent bent parts of the laminate films 31 and 32. Therefore, the entry of oxygen and moisture into the power storage device 1 can be effectively suppressed.
Hereinafter, other examples of preferred embodiments of the present invention are described. In the following description, members having substantially the same functions as those in the first embodiment are referred to with the same reference numerals, and description thereof is omitted.
In the first embodiment, the example has been described in which the power storage device 1 has a rectangular shape in plan view. However, the present invention is not limited to this configuration. In the present invention, the shape of the power storage device is appropriately determined depending on an arrangement space of the power storage device. For example, as shown in
As shown in
As shown in
In the power storage devices 1c and 1d, as in the first embodiment, the sealing material 4 is provided on an outer peripheral surface of the device body 2, and the sealing material 4 is also provided on an inner peripheral surface thereof. Similarly to the outer peripheral surface of the device body 2, the first laminate film 31 and the second laminate film 32 are connected to each other on the inner peripheral surface by the sealing material 4. Specifically, the first and second laminate films 31 and 32 have at least one cuts 31a and 32a, and have bent parts that are bent along the inner peripheral surface. The sealing material 4 connects the first laminate film 31 and the second laminate film 32, and is provided across the cuts 31a and 32a. With this configuration, also in the power storage devices 1c and 1d having the through holes, the energy density per unit area of the power storage devices 1c and 1d can be increased as in the first to third embodiments. In addition, the entry of oxygen and moisture into the power storage devices 1c and 1d can be effectively suppressed.
(First to Third Modifications)
In the first to fifth embodiments, the example has been described in which both the first and second laminate films 31 and 32 are bent and the end surfaces of both of the laminate films 31 and 32 are in contact with each other. However, the present invention is not limited to this configuration.
For example, as shown in
For example, as shown in
For example, as shown in
(Other Modifications)
In the embodiments and the modifications described above, the example has been described in which the sealing material 4 is provided on the side surface of the device body 2. However, the present invention is not limited to this configuration. For example, the sealing material 4 may be provided so as to cover at least a part of the main surface in addition to the side surface, or may be provided so as to cover the device body 2.
A power storage device according to the present invention includes a device body, a package, and a sealing material. The device body includes a negative electrode, a positive electrode, and a separator. The separator is provided between the negative electrode and the positive electrode. The package has a shape corresponding to a shape of the device body. The package accommodates the device body. The package includes a first laminate film, and a second laminate film. The first laminate film is provided on one side in a laminating direction of the device body. The second laminate film is provided on the other side in the laminating direction of the device body. The sealing material connects the first laminate film and the second laminate film on a side surface of the device body.
In the power storage device of the present invention, the sealing material that connects the first laminate film and the second laminate film is provided on the side surface of the device body. Accordingly, the sealing part of the package can be made small. Therefore, the power storage device in plan view can be reduced in area, and the energy density per unit area of the power storage device can be increased.
It is preferable that the sealing material and each of the first and second laminate films be bonded together. In this case, on the side surface of the device body, the portions where the first and second laminate films are connected are securely sealed by the sealing material, so that the electrolyte and the like are difficult to leak, and moisture, oxygen and the like are less likely to enter into the package.
It is preferable that at least one of the first and second laminate films have a bent part that is bent along the side surface of the device body, and the bent part be connected to the sealing material. In this case, the power storage device can be further downsized.
The device body may have a corner part at an intersection of two adjacent side surfaces. In that case, it is preferable that at least one of the first and second laminate films have the cut or notch positioned on the corner part, and the sealing material be provided across the cut or notch. According to this configuration, it is possible to effectively prevent oxygen and moisture from entering the inside of the power storage device.
The inner angle of the corner part may be larger than 90°.
The device body may have a through hole penetrating in the laminating direction, and the corner part may be provided in the through hole.
The device body may have a curved side surface. In that case, at least one of the first and second laminate films may have the cut or notch positioned on the curved side surface, and the sealing material may be provided across the cut or notch.
The device body may have a through hole penetrating in the laminating direction, and the curved side surface may be in the through hole.
Number | Date | Country | Kind |
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2017-166481 | Aug 2017 | JP | national |
The present application is a continuation of International application No. PCT/JP2018/030959, filed Aug. 22, 2018, which claims priority to Japanese Patent Application No. 2017-166481, filed Aug. 31, 2017, the entire contents of each of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2018/030959 | Aug 2018 | US |
Child | 16781210 | US |