KR102631758B1 - Adhesive films and batteries for metal terminals - Google Patents

Abstract

An adhesive film for metal terminals that has high adhesion to packaging materials and metal terminals and also has excellent electrolyte resistance is provided. An adhesive film for metal terminals interposed between a metal terminal electrically connected to an electrode of a battery element and a packaging material that seals the battery element, wherein the adhesive film for a metal terminal has at least one layer of polypropylene. layer and at least one acid-modified polypropylene layer, wherein the acid-modified polypropylene layer constitutes a surface layer on at least one side of the adhesive film for metal terminals, and the poly When the propylene layer is observed in cross section through an electron micrograph, a sea-island structure is observed, and when the total thickness of the acid-modified polypropylene layer is set to 1, the total thickness of the polypropylene layer is 0.7 or more and 3.5 or less. Adhesive films for metal terminals within the range.

Description

Adhesive films and batteries for metal terminals

The present invention relates to adhesive films for metal terminals and batteries.

Conventionally, various types of batteries have been developed, but in all batteries, packaging materials are an essential member to seal battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been widely used as battery packaging, but in recent years, with the increased performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., various shapes are required for batteries, and there is a demand for thinner and lighter batteries. It is becoming. However, metal packaging materials that have been widely used in the past have the disadvantage of being difficult to keep up with the diversification of shapes and further limiting weight reduction.

Therefore, in recent years, a film-type laminate in which a base layer/adhesive layer/barrier layer/heat-sealable resin layer is sequentially laminated has been proposed as a packaging material that is easy to process into various shapes and can realize thinner and lighter weight. When using such a film-type packaging material, the heat-sealable resin layers located in the innermost layer of the packaging material are opposed to each other, and the peripheral portion of the packaging material is heat-sealed with a heat seal, thereby sealing the battery element with the packaging material. do.

A metal terminal protrudes from the heat seal portion of the packaging material, and the battery element sealed by the packaging material is electrically connected to the outside by a metal terminal electrically connected to an electrode of the battery element. That is, among the portions where the packaging material is heat-sealed, the portion where the metal terminal is present is heat-sealed with the metal terminal sandwiched between the heat-sealable resin layer. Since the metal terminal and the heat-sealable resin layer are made of different materials, adhesion is likely to decrease at the interface between the metal terminal and the heat-sealable resin layer.

For this reason, an adhesive film is sometimes disposed between the metal terminal and the heat-sealable resin layer for the purpose of improving their adhesion.

Japanese Patent Publication No. 2015-79638

In addition to high adhesion to the packaging material and the metal terminal, such an adhesive film is also required to have excellent resistance to the electrolyte solution sealed by the packaging material.

Under these circumstances, the main purpose of the present invention is to provide an adhesive film for metal terminals that has high adhesion to packaging materials and metal terminals and also has excellent electrolyte resistance. Additionally, the present invention also aims to provide a battery using the adhesive film for metal terminals.

The present inventors conducted intensive studies to solve the above problems. As a result, it is an adhesive film for metal terminals that is interposed between a metal terminal electrically connected to the electrode of a battery element and a packaging material that seals the battery element, and the adhesive film for a metal terminal has at least one layer of poly. It is composed of a laminate including a propylene layer and at least one acid-modified polypropylene layer, wherein the acid-modified polypropylene layer constitutes a surface layer on at least one side of the adhesive film for metal terminals, and When the polypropylene layer is observed in cross section through an electron micrograph, a sea-island structure is observed, and when the total thickness of the acid-modified polypropylene layer is set to 1, the total thickness of the polypropylene layer is in the range of 0.7 to 3.5. It was found that the adhesive film for metal terminals inside has high adhesion to the packaging material and metal terminals and is also excellent in electrolyte resistance. The present invention was completed through further examination based on this knowledge.

That is, the present invention provides the invention in the aspects shown below.

Item 1. An adhesive film for metal terminals interposed between a metal terminal electrically connected to an electrode of a battery element and a packaging material that seals the battery element,

The adhesive film for metal terminals is composed of a laminate including at least one polypropylene layer and at least one acid-modified polypropylene layer,

The acid-modified polypropylene layer constitutes a surface layer on at least one side of the adhesive film for metal terminals,

When the polypropylene layer is observed in cross section through an electron microscope photograph, a sea-island structure is observed,

An adhesive film for metal terminals wherein, when the total thickness of the acid-modified polypropylene layers is set to 1, the total thickness of the polypropylene layers is within the range of 0.7 to 3.5.

Item 2. The adhesive film for metal terminals according to Item 1, wherein the polypropylene layer contains block polypropylene.

Item 3. The adhesive film for metal terminals according to Item 1 or 2, wherein the polypropylene layer is made of unstretched polypropylene.

Item 4. Items 1 to 3, wherein the polypropylene layer has a lamination structure in which a layer made of random polypropylene, a layer made of block polypropylene, and a layer made of random polypropylene are laminated in this order. The adhesive film for metal terminals according to any one of the above.

Item 5. Adhesiveness for metal terminals according to any one of Items 1 to 4, wherein a melting peak is observed in the range of 150°C or more and 165°C or less when the adhesive film for metal terminals is measured with a differential scanning calorimeter. film.

Item 6. The adhesive film for metal terminals according to any one of Items 1 to 5, wherein the adhesive film for metal terminals has a thickness residual ratio of 50% or more, as measured by the following measurement method.

An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.

Measure the thickness A (μm) of the adhesive film for metal terminals.

The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.

Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.

The thickness B (μm) of the heated and pressurized portion of the laminate is measured.

The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.

Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100

Item 7. The adhesive film for metal terminals according to any one of items 1 to 6, wherein the adhesive film for metal terminals has a heat shrinkage rate in the flow direction of 70 to 90%.

Clause 8. The packaging material is composed of a laminate comprising at least a base layer, a barrier layer, and a heat-sealable resin layer in this order,

The adhesive film for metal terminals according to any one of items 1 to 7, wherein the adhesive film for metal terminals is interposed between the heat-sealable resin layer and the metal terminal.

Item 9. At least a battery element having a positive electrode, a negative electrode, and an electrolyte, a packaging material for sealing the battery element, and a metal terminal electrically connected to each of the positive electrode and the negative electrode and protruding outside of the packaging material. It is a battery provided with,

A battery comprising the adhesive film for metal terminals according to any one of items 1 to 8 interposed between the metal terminal and the packaging material.

Item 10. Use of a laminate comprising at least one polypropylene layer and at least one acid-modified polypropylene layer,

The acid-modified polypropylene layer constitutes a surface layer on at least one side of the adhesive film for metal terminals,

When the polypropylene layer is observed in cross section through an electron microscope photograph, a sea-island structure is observed,

When the total thickness of the acid-modified polypropylene layer is 1, the total thickness of the polypropylene layer is within the range of 0.7 to 3.5,

Use of the laminate as an adhesive film for metal terminals, which is interposed between a metal terminal electrically connected to an electrode of a battery element and a packaging material that seals the battery element.

According to the present invention, it is possible to provide an adhesive film for metal terminals that has high adhesion to packaging materials and metal terminals and also has excellent electrolyte resistance. Furthermore, according to the present invention, a battery using the adhesive film for metal terminals can be provided.

1 is a schematic plan view of the battery of the present invention.
FIG. 2 is a schematic cross-sectional view taken along line A-A' in FIG. 1.
FIG. 3 is a schematic cross-sectional view taken along line B-B' in FIG. 1.
Figure 4 is a schematic cross-sectional view of the adhesive film for metal terminals of the present invention.
Figure 5 is a schematic cross-sectional view of the adhesive film for metal terminals of the present invention.
Figure 6 is a schematic cross-sectional view of the packaging material used in the battery of the present invention.
Figure 7 is a schematic diagram for explaining the method of measuring seal strength in an example.
Figure 8 is a schematic diagram for explaining the method of measuring seal strength in an example.
Figure 9 is a schematic diagram for explaining the method of measuring seal strength in an example.
Fig. 10 is a schematic diagram for explaining the method of measuring seal strength in an example.
Figure 11 is “Polymer Micro Photo Collection: Macromolecules as Seen with the Eyes 1. Shape and Function of Molecular Assembly” (Editor: Polymer Society, Publisher: Itaru Yamamoto, Publisher: Baifukan Co., Ltd., May 30, 1986 This is a transmission electron microscope photo (scale bar is 5 μm) indicated as “C” on page 29 of the first edition.

The adhesive film for metal terminals of the present invention is an adhesive film for metal terminals interposed between a metal terminal electrically connected to the electrode of a battery element and a packaging material that seals the battery element, and has adhesive properties for metal terminals. The film is composed of a laminate including at least one polypropylene layer and at least one acid-modified polypropylene layer, and the acid-modified polypropylene layer is on at least one side of the adhesive film for metal terminals. It constitutes the surface layer of, and the polypropylene layer has a sea-island structure when the cross-section is observed through an electron micrograph, and when the total thickness of the acid-modified polypropylene layer is set to 1, the total thickness of the polypropylene layer is A, it is characterized by being within the range of 0.7 or more and 3.5 or less. Hereinafter, the adhesive film for metal terminals of the present invention and the battery of the present invention using the same will be described in detail.

In addition, in this specification, the numerical range indicated by “to” means “not less than” and “not more than”. For example, the notation 2 to 15 mm means 2 mm or more and 15 mm or less.

1. Adhesive film for metal terminals

The adhesive film for metal terminals of the present invention is interposed between a metal terminal electrically connected to an electrode of a battery element and a packaging material that seals the battery element. Specifically, as shown, for example, in FIGS. 1 to 3, the adhesive film for metal terminals 1 of the present invention includes a metal terminal 2 electrically connected to the electrode of the battery element 4, It is sandwiched between packaging materials 3 that seal the battery element 4. In addition, the metal terminal 2 protrudes to the outside of the packaging material 3 and is heat-sealed at the peripheral portion 3a of the packaging material 3 via the metal terminal adhesive film 1, It is sandwiched and supported in the packaging material (3). Additionally, in the present invention, the heat when heat sealing the packaging material is usually in the range of about 160 to 220°C, and the pressure is usually in the range of about 0.5 to 2.0 MPa.

The adhesive film for metal terminals (1) of the present invention is provided to increase the adhesion between the metal terminal (2) and the packaging material (3). As the adhesion between the metal terminal 2 and the packaging material 3 increases, the sealing performance of the battery element 4 improves. As described above, when heat sealing the battery element 4, the metal terminal 2 electrically connected to the electrode of the battery element 4 is made to protrude to the outside of the packaging material 3, so that the battery element is sealed. do. At this time, the metal terminal 2 formed of metal and the heat-sealable resin layer 34 (a layer formed of heat-sealable resin such as polyolefin) located in the innermost layer of the packaging material 3 are made of different materials. Since the adhesive film is not used, the sealing performance of the battery element is likely to be lowered at the interface between the metal terminal 2 and the heat-sealable resin layer 34. Moreover, even when an adhesive film is used, if the electrolyte solution resistance of the adhesive film is low, the sealing performance of the battery element is likely to be low.

For example, as shown in FIGS. 4 and 5, the adhesive film for metal terminals 1 of the present invention includes at least one layer of polypropylene layer 11 and at least one layer of acid-modified polypropylene layer 12. ), the acid-modified polypropylene layer 12 constitutes the surface layer of at least one side of the adhesive film for metal terminal 1, and the polypropylene layer 11 has a cross-section. When observed with an electron micrograph, a sea-island structure is observed, and when the total thickness of the acid-modified polypropylene layer 12 is set to 1, the total thickness of the polypropylene layer 11 is in the range of 0.7 to 3.5. It is set to mine. As a result, the adhesive film for metal terminals 1 of the present invention has high adhesion to the packaging material and the metal terminal and also has excellent electrolyte resistance, so that the sealing property of the battery element can be effectively improved.

From the viewpoint of further improving the electrolyte resistance while increasing adhesion to the packaging material and the metal terminal, the total thickness of the acid-modified polypropylene layer 12 is assumed to be 1. The thickness is preferably within the range of about 0.75 to 3.2, more preferably within the range of about 0.8 to 2.0.

In the adhesive film for metal terminals 1 of the present invention, the acid-modified polypropylene layer 12 constitutes the surface layer on at least one side of the adhesive film for metal terminals. The acid-modified polypropylene layer 12 made of acid-modified polypropylene has excellent adhesion to metal materials compared to the polypropylene layer 11 made of polypropylene. For this reason, the acid-modified polypropylene layer 12 is positioned on the metal terminal 2 side, and the adhesive film for metal terminals 1 of the present invention is placed between the metal terminal 2 and the packaging material 3. By arranging this, the sealability of the battery element can be effectively improved.

The adhesive film for metal terminals 1 of the present invention may include at least one polypropylene layer 11 and an acid-modified polypropylene layer 12 each. A preferred lamination configuration of the adhesive film 1 for a metal terminal of the present invention is, for example, as shown in FIG. 4, a configuration in which a polypropylene layer 11 and an acid-modified polypropylene layer 12 are laminated one layer at a time. , for example, as shown in FIG. 5 , a structure in which one acid-modified polypropylene layer 12 is laminated on both sides of the polypropylene layer 11, etc. In addition, as will be described later, in the one-layer polypropylene layer 11, a plurality of layers made of the same or different polypropylene are laminated in succession, and the plurality of layers constitute the one-layer polypropylene layer 11. You can do it. Similarly, in the one-layer acid-modified polypropylene layer 12, a plurality of layers made of the same or different acid-modified polypropylene are laminated in succession, and the plurality of layers form one layer of acid-modified polypropylene layer 12. You may configure it.

Specific examples of a preferable lamination structure of the adhesive film for metal terminals 1 of the present invention include a two-layer structure of acid-modified polypropylene layer 12/polypropylene layer 11; A three-layer structure in which acid-modified polypropylene layer 12/polypropylene layer 11/acid-modified polypropylene layer 12 are laminated in this order; A five-layer structure in which acid-modified polypropylene layer 12/polypropylene layer 11/acid-modified polypropylene layer 12/polypropylene layer 11/acid-modified polypropylene layer 12 are laminated in this order, etc. Among these, a two-layer structure of acid-modified polypropylene layer 12/polypropylene layer 11; A three-layer structure in which the acid-modified polypropylene layer 12/polypropylene layer 11/acid-modified polypropylene layer 12 is laminated in this order is more preferable.

It is preferable that all layers of the adhesive film for metal terminals (1) of the present invention are made of polyolefin. More specifically, the adhesive film for metal terminals 1 of the present invention is preferably comprised only of the acid-modified polypropylene layer 12 and the polypropylene layer 11, and other than that comprised of polyolefin. An embodiment further comprising a polyolefin layer is also preferable. Specific examples of polyolefin constituting the polyolefin layer include polyethylene, acid-modified polyethylene, and the like. In acid-modified polyethylene, the component for acid-modifying ethylene is not particularly limited, but examples include unsaturated carboxylic acids and their anhydrides used for acid-modification as exemplified in the acid-modified polypropylene layer 12 described later. You can.

The thickness of the adhesive film for metal terminals 1 of the present invention is not particularly limited, but is preferably 40 to 40 from the viewpoint of further improving the electrolyte resistance while increasing adhesion to the packaging material and the metal terminal. About 200 μm, more preferably about 55 to 150 μm, and even more preferably about 60 to 110 μm.

In addition, from the viewpoint of further improving the electrolyte solution resistance while further increasing the adhesion to the packaging material and the metal terminal, when the adhesive film (1) for a metal terminal of the present invention is measured with a differential scanning calorimeter, the temperature is 150 to 150%. It is preferable that the melting peak is observed in the range of 165°C.

Also, from the same viewpoint, the adhesive film for metal terminals 1 of the present invention preferably has a thickness residual ratio of the adhesive film for metal terminals measured by the following measurement method of about 50% or more, and is about 55%. It is preferable that it is % or more, and it is preferable that it is about 60% or more. Regarding the upper limit of the thickness residual ratio, it is preferably about 90% or less, preferably about 85% or less, and preferably about 80% or less. The range of the thickness residual ratio is preferably about 55 to 90%, about 55 to 85%, about 55 to 80%, about 60 to 90%, about 60 to 85%, and about 60 to 80%. . By using the adhesive film for metal terminals (1) with a residual ratio of 50% or more, short circuiting between the barrier layer contained in the packaging material and the metal terminal can be effectively suppressed, and further, the adhesive film for metal terminals and the packaging material can be effectively suppressed. It becomes possible to further increase adhesion. Additionally, by using the adhesive film 1 for metal terminals with a residual ratio of 90% or less, the shape of the step of the metal terminal can be suitably followed and the ends of the metal terminal can be suitably covered.

(Measurement of thickness residual rate of adhesive film for metal terminal)

Prepare an aluminum plate (pure aluminum type, JIS H4160-1994 A1N30H-O) with a thickness of 100 μm and an adhesive film for metal terminals. Measure the thickness A (μm) of the adhesive film for metal terminals with a micro gauge. The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate. At this time, the acid-modified polypropylene layer of the adhesive film for metal terminals is placed in contact with the aluminum plate. Prepare two metal plates that are longer than the length of the aluminum plate and have a width of 7 mm, and cover the entire surface of the adhesive film for metal terminals. From the top and bottom of the aluminum plate and the adhesive film for metal terminals, the temperature is 190°C and the surface pressure is 1.27. Heating and pressurization are performed under the conditions of MPa and 3 seconds to obtain a laminate of an aluminum plate and an adhesive film for metal terminals. The thickness B (μm) of the heated and pressurized portion of the laminate is measured with a micro gauge. The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.

Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100

In addition, the longitudinal direction is the direction of the long side corresponding to the long side when viewed in the plane of the object, and the width direction is the direction of the short side corresponding to the short side when viewed in the plane of the object. When the size of the length direction and the width direction are the same (square), either the length direction or the width direction may be used.

In addition, in measuring the residual ratio, depending on the area of the adhesive film for metal terminals, the measurement may be performed by applying a pressing load so that the surface pressure is 1.27 MPa. Specifically, it can be converted by the equation [pressing load by the metal plate (N)]/[area pressing the adhesive film for metal terminals (mm ² )] = surface pressure (MPa). Additionally, the load N applied by the metal plate can be adjusted by the diameter of the cylinder or air pressure that adjusts the pressure of the metal plate.

In measuring the thickness residual ratio of the adhesive film for metal terminals described above, if the measurement is performed under the conditions of a temperature of 190°C, a surface pressure of 1.27 MPa, and a time of 3 seconds, the length and width of the adhesive film for metal terminals and the aluminum plate are limited. Although this is not possible, for example, if measurement is possible with an adhesive film for metal terminals of 70 mm in length and 5 mm in width (a method such as cutting may be used), the adhesive film for metal terminals of this size and an aluminum plate can be used to measure the length. Using a film measuring 60 mm and 25 mm in width, the thickness residual ratio of the adhesive film for metal terminals can be appropriately measured. In addition, [the area where the adhesive film for metal terminals is pressed (mm ² )] is the area of the part where the aluminum plate and the adhesive film for metal terminals overlap, for example, the adhesive films for metal terminals of these sizes and In the case of using an aluminum plate, the area is 60 mm x 5 mm. Additionally, the thickness of the aluminum plate does not substantially change due to heating and pressurization when obtaining the laminate of the aluminum plate and the adhesive film for metal terminals. Even if the sizes of the adhesive films for metal terminals to be measured are different, if the above measurement can be performed, there is no need to change the size of the aluminum plate.

The melt mass flow rate (MFR) of the entire adhesive film for metal terminals (1) of the present invention is not particularly limited, but from the viewpoint of further improving the electrolyte resistance while increasing the adhesion with the packaging material and the metal terminal. , preferably about 1 to 15, more preferably about 2 to 12, and even more preferably about 3 to 10. The melt mass flow rate (MFR) of the entire adhesive film for metal terminals (1) was measured using a melt indexer at a measurement temperature of 230°C and a load of 2.16 kg using a method based on JIS K7210:2014. It is a value.

In addition, the lower limit of the heat shrinkage rate (%) in the flow direction (MD) of the adhesive film for metal terminals 1 of the present invention is preferably about 70% or more, more preferably about 75% or more, and even more preferably Preferably it is about 80% or more, and the upper limit is preferably about 95% or less, more preferably about 92% or less, and even more preferably about 90% or less. In addition, the range of the heat shrinkage rate (%) is preferably about 70 to 95%, about 70 to 92%, about 70 to 90%, about 75 to 95%, about 75 to 92%, and about 75 to 90%. , about 80 to 95%, about 80 to 92%, and about 80 to 90%. The measuring method of the heat shrinkage rate (%) is as follows.

(Method for measuring heat shrinkage (%))

The adhesive film for metal terminals is cut to a size of 50 mm in length (MD) x 4 mm in width (TD) and used as a test piece. Next, measure the length M (mm) of the test piece with a metal ruler. Next, the longitudinal end of the test piece is fixed to the metal mesh with tape, and the test piece is hung from the metal mesh. In this state, after placing it in an oven heated to 190°C for 120 seconds, the test piece is taken out from each metal mesh and cooled naturally in a room temperature (25°C) environment. Next, measure the length N (mm) of the test piece naturally cooled to room temperature with a metal ruler. The heat shrinkage rate of the adhesive film for metal terminals is calculated using the formula below.

Heat shrinkage rate (%) = (length N/length M) x 100

Additionally, when sealing a battery element, when the adhesive film for metal terminals is heat-sealed in a state sandwiched between the metal terminal and the packaging material, the metal terminal is sealed by pressure from the metal plate used for heat sealing. There are parts where the adhesive film does not change dimensions and parts where pressure is not applied and shrinks due to the distance from the metal plate. At this time, if heat shrinks appropriately toward the part to which pressure is applied, even to the part where pressure is not applied, the thickness of the part to which pressure is applied can be effectively prevented from becoming too thin. On the other hand, when the heat shrinkage of the adhesive film for metal terminals is too large, the adhesive film 1 for metal terminals is installed on the metal terminals, and the adhesive film for metal terminals is used in the preheating step before being applied to the heat seal. There is a risk that the positional relationship between the metal terminal and the adhesive film for metal terminal may be misaligned due to movement due to this heat shrinkage. For this reason, it is preferable that the adhesive film for metal terminals 1 of the present invention has an appropriate heat shrinkage rate. In addition, as an appropriate heat shrinkage rate of the adhesive film for metal terminals 1 of the present invention, for example, the lower limit of the heat shrinkage rate (%) in the flow direction (MD) described above is 70% or more.

(polypropylene layer (11))

In the present invention, the polypropylene layer 11 is a layer made of polypropylene. Additionally, a sea-island structure is observed when the polypropylene layer 11 is observed in cross section through an electron micrograph. Observing a sea-island structure in the cross section of the polypropylene layer 11 means that a sea portion and an island portion are observed, for example, as in the electron micrograph shown in FIG. 11. Figure 11 is “Polymer Micro Photo Collection: Macromolecules as Seen with the Eyes 1. Shape and Function of Molecular Assembly” (Editor: Polymer Society, Publisher: Itaru Yamamoto, Publisher: Baifukan Co., Ltd., May 30, 1986 This is a transmission electron micrograph (scale bar is 5 μm) shown as “C” on page 29 of the first edition. The sea-island structure in the cross section of the polypropylene layer 11 can be confirmed by staining the cross section of the polypropylene layer with osmium tetroxide (OsO ₄ ) and observing an electron micrograph, as shown in FIG. 11 . Additionally, in Figure 11, the sea portion is brighter than the island portion, but depending on the measurement method and conditions, the ocean portion may appear darker than the island portion. In any case, if the sea portion and the island portion can be distinguished, the ratio of the area of the island portion in the chart structure can be measured.

In the sea-island structure of the polypropylene layer 11, the ratio of the area of the island portion is not particularly limited, but is preferable from the viewpoint of further improving the electrolyte resistance while increasing adhesion to the packaging material and the metal terminal. Typically, it is about 10 to 50%, more preferably about 20 to 40%. The method for measuring the ratio of the area of the island portion in the sea-island structure of the polypropylene layer 11 is as follows. Additionally, when the ratio of the area of the island portion is 2% or less, it is evaluated that it does not substantially have a sea-island structure.

(Method of measuring the ratio of the area of the island portion in the chart structure)

The adhesive film for metal terminals is embedded in a thermosetting epoxy resin and cured. A commercially available rotary microtome (UC6 manufactured by LEICA) and a diamond knife were used to produce a cross section in the desired direction (cross section along TD), and then a cross section was prepared at -70°C using a cryomicrotome using liquid nitrogen. do it Each embedding resin is stained with ruthenium tetroxide overnight. Since polypropylene expands when dyed, the expanded portion is trimmed with a microtome, and the portion further cut to a thickness of about 100 nm and about 1 to 2 μm is observed as follows. The stained cross section was observed with a field emission scanning electron microscope (e.g., S-4800 TYPE1 manufactured by Hitachi High-Technologies, measurement conditions: 3kV 20mA High WD6mm detector (Upper)) and images (magnification: 10000x) were obtained. acquire. Next, using image processing software that can binarize the image (for example, image analysis software WinROOF (Ver7.4) manufactured by Mitani Shoji), the island portion and the sea portion of the chart structure are divided into two parts for the image. Denaturation is performed to obtain the ratio of the area occupied by the island portion (total area of the island portion/area of the measurement range of the image). For specific image processing conditions, for example, the conditions described in the examples are adopted.

When a cross-section of the polypropylene layer 11 is observed with an electron micrograph, if a sea-island structure is observed, the cold resistance strength increases while maintaining the excellent heat resistance of the adhesive film for metal terminals. Additionally, adhesion to packaging materials and metal terminals increases, and electrolyte resistance also improves.

Additionally, in the present invention, the polypropylene layer 11 is preferably made of unstretched polypropylene. The fact that the polypropylene layer 11 is made of unstretched polypropylene and not made of stretched polypropylene can be confirmed by analyzing the polypropylene layer 11 using an X-ray diffraction method. Specifically, when measuring the wide-angle The ratio of the intensity of the peak corresponding to the 110 side (peak intensity of the 040 side/peak intensity of the 110 side) is within the range of 0.5 to 1.5, and the polypropylene layer composed of stretched polypropylene falls outside this range. do. That is, in the present invention, the polypropylene layer 11, when measuring wide-angle It is made of polypropylene whose peak intensity ratio (peak intensity of the 040 side/peak intensity of the 110 side) is in the range of 0.5 to 1.5.

Additionally, the peak corresponding to the 110 plane appears around 2θ = 14°, and the peak corresponding to the 040 plane appears around 2θ = 17°. The measurement conditions by wide-angle Soller (aperture angle of light-receiving parallel slit): 5.0 deg, 2θ/θ: 2 to 40 deg, step is 0.04 deg.

In addition, the fact that the polypropylene layer 11 is composed of unstretched polypropylene and not stretched polypropylene can be confirmed by analyzing the polypropylene layer 11 using Raman spectroscopy. Specifically, when the polypropylene layer is analyzed by Raman spectroscopy, the crystalline peak intensity height "A" is expressed as approximately 809 cm ^-1 and the amorphous peak intensity height "B" is expressed as approximately 842 cm ^-1 When the ratio (A/B) is 1.6 or less, it can be confirmed that the polypropylene layer 11 is made of unstretched polypropylene. The measurement conditions are laser wavelength 633nm, grid 600gr/mm, confocal hole 100㎛, microscope lens 10x, exposure time 15sec, number of integrations 1, and a cross section parallel to the MD (Machine Direction) of the polypropylene layer 11. For , the Raman spectrum was measured so that the MD and the incident laser polarization plane were parallel. In addition, the straight line connecting 710 cm ^-1 and 925 cm ^-1 was used as the baseline. As for the analysis conditions, the peak heights at 809 cm ^-1 and 842 cm ^-1 when baseline correction was performed were calculated as peak intensity. In addition, the crystalline peak intensity height "A" expressed above at about 809 cm ^-1 is a peak attributed to the combination mode of main chain CC stretching and CH3 deflection vibration. In addition, the height "B" of the amorphous peak intensity expressed at about 842 cm ^-1 is a peak attributed to the CH3 variable angle vibration mode.

In the present invention, the method for confirming the MD of the polypropylene layer 11 is as follows. For the cross section in the longitudinal direction of the polypropylene layer 11, the angle is changed by 10 degrees from the direction parallel to the cross section in the longitudinal direction, and each cross section up to the direction perpendicular to the cross section in the longitudinal direction (a total of 10 cross sections) , respectively, by observing them with electron micrographs to confirm their structure. Next, the shape of each island is observed in each cross section. For the shape of each island, the straight line distance connecting the leftmost end in a direction perpendicular to the thickness direction of the polypropylene layer 11 and the rightmost end in the vertical direction is referred to as diameter y. In each cross section, the average of the top 20 diameters y, which is the island shape, is calculated in descending order of diameter y. The direction parallel to the cross section in which the average of the diameter y, which is the shape of the island, is largest is determined to be MD.

The polypropylene contained in the polypropylene layer 11 is preferably homopolypropylene, a block copolymer of polypropylene (e.g., a block copolymer of propylene and ethylene), and a random copolymer of polypropylene (e.g., , random copolymers of propylene and ethylene) and other crystalline or amorphous polypropylenes. Compositions in which the polypropylene layer 11 has the above-mentioned sea-island structure include, for example, a composition in which the polypropylene layer 11 contains a block copolymer of polypropylene, a random copolymer of a block copolymer of polypropylene and a polypropylene. A composition containing a composition, a composition containing homo polypropylene, random polypropylene, and polyethylene components, etc. Among these, it is more preferable that the polypropylene layer 11 contains block polypropylene, and it is still more preferable that it is comprised of block polypropylene. Additionally, the proportion of propylene contained in block polypropylene is preferably about 10 to 90% by mass, and more preferably about 30 to 80% by mass.

In the adhesive film for metal terminals 1 of the present invention, the polypropylene layer 11 may be one layer or two or more layers. In addition, in the one-layer polypropylene layer 11, a plurality of layers made of the same or different polypropylene may be successively laminated, and the plurality of layers may constitute the one-layer polypropylene layer 11. The polypropylene layer 11 preferably includes a layer made of block polypropylene.

As a preferred form of the one-layer polypropylene layer 11, it is preferable that it is a laminate of a layer made of random polypropylene and a layer made of block polypropylene, and in particular, a layer made of random polypropylene and a layer made of block polypropylene. It is preferable to have a laminated structure (three-layer structure) in which a layer made of propylene and a layer made of random polypropylene are laminated in this order.

In addition, in the present invention, when a plurality of layers made of polypropylene are laminated in succession, these layers are collectively referred to as one polypropylene layer 11. Similarly, when a plurality of layers made of acid-modified polypropylene are laminated in succession, these layers are collectively referred to as one acid-modified polypropylene layer 12.

The thickness of the first-layer polypropylene layer 11 is not particularly limited as long as the total thickness of the polypropylene layer 11 is within the range of 0.7 to 3.5 when the total thickness of the acid-modified polypropylene layer 12 is 1. However, from the viewpoint of further improving the electrolyte solution resistance while increasing adhesion to the packaging material and the metal terminal, the thickness is preferably about 15 to 80 μm, and more preferably about 20 to 70 μm. In addition, although the details are not clear, if the thickness of the acid-modified polypropylene layer is too large, cohesive failure of the acid-modified polypropylene layer is likely to occur, and the adhesion of the adhesive film for metal terminals tends to tend to decrease. .

From the viewpoint of further improving the electrolyte resistance while further increasing the adhesion to the packaging material and the metal terminal, in the adhesive film for metal terminals 1, the polypropylene layer 11 is an adhesive film for metal terminals ( 1) It is preferable that it occupies about 40% or more of the thickness, and it is more preferable that it occupies about 45% or more, and as an upper limit, the polypropylene layer 11 accounts for about 85% of the thickness of the adhesive film for metal terminal 1. It is preferable that it occupies less than about 80%, and more preferably it occupies about 80% or less. A preferable range of the thickness of the polypropylene layer 11 that accounts for the thickness of the adhesive film for metal terminals 1 includes approximately 40 to 85% and approximately 45 to 80%.

The melting peak temperature of the polypropylene layer 11 is not particularly limited, but is preferably about 140 to 165° C. from the viewpoint of further improving the electrolyte resistance while increasing adhesion to the packaging material and the metal terminal. More preferably, it is around 150 to 160°C. In addition, in the present invention, the melting peak temperature of the polypropylene layer 11 is a value measured using a differential scanning calorimeter (DSC), and the temperature increase rate is 10°C/min and the temperature measurement range is -50 to 200°C. and is measured using an aluminum pan as a sample pan.

(Acid modified polypropylene layer (12))

In the present invention, the acid-modified polypropylene layer 12 is a layer made of acid-modified polypropylene. Also for the acid-modified polypropylene layer 12, it is preferable that a sea-island structure is observed when the cross section is observed with an electron micrograph. Additionally, the confirmation method for the island-in-sea structure in the acid-modified polypropylene layer 12 is the same as the confirmation method in the polypropylene layer 11 described above.

In the sea-island structure of the acid-modified polypropylene layer 12, the ratio of the area of the island portion is not particularly limited, but from the viewpoint of further improving the electrolyte resistance while increasing the adhesion to the packaging material and the metal terminal. , preferably about 10 to 50%, more preferably about 20 to 40%. The method for measuring the ratio of the area of the island portion in the sea-island structure of the acid-modified polypropylene layer 12 is the polypropylene layer 11 described above, except that the measurement target is the acid-modified polypropylene layer 12. It is the same as the measurement method in . Additionally, when the ratio of the area of the island portion is 2% or less, it is evaluated that it does not substantially have a sea-island structure.

The acid-modified polypropylene is not particularly limited as long as it is acid-modified polypropylene, but preferably includes polypropylene graft-modified with an unsaturated carboxylic acid or its anhydride. Examples of unsaturated carboxylic acids or their anhydrides used for acid modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride.

The acid-modified polypropylene is preferably homopolypropylene, block copolymer of polypropylene (e.g., block copolymer of propylene and ethylene), and random copolymer of polypropylene (e.g., random copolymer of propylene and ethylene). crystalline or amorphous polypropylene such as copolymer). Among these, it is preferable that it contains a block copolymer of polypropylene (block polypropylene) or a random copolymer of polypropylene (random polypropylene). In addition, the fact that the acid-modified polypropylene layer 12 is a layer made of acid-modified polypropylene can be analyzed by infrared spectroscopy, gas chromatography-mass spectrometry, etc., and the analysis method is not particularly limited. For example, when maleic anhydride modified polypropylene is measured using infrared spectroscopy, peaks derived from maleic anhydride are detected around wavenumber 1760cm ^-1 and wavenumber 1780cm ^-1 . However, if the degree of acid denaturation is low, the peak becomes small and may not be detected. In that case, it can be analyzed using nuclear magnetic resonance spectroscopy.

In the adhesive film for metal terminals 1 of the present invention, the acid-modified polypropylene layer 12 may be one layer or two or more layers. In addition, in the one-layer acid-modified polypropylene layer 12, a plurality of layers made of the same or different acid-modified polypropylene are laminated in succession, and the plurality of layers form one layer of acid-modified polypropylene layer 12. You may configure it.

A preferable form of the first acid-modified polypropylene layer 12 includes a layer made of maleic anhydride-modified polypropylene.

The thickness of the acid-modified polypropylene layer 12 of the first layer is particularly high if the total thickness of the polypropylene layers 11 when the total thickness of the acid-modified polypropylene layer 12 is 1 is within the range of 0.7 to 3.5. Although not limited, from the viewpoint of further improving the electrolyte solution resistance while increasing adhesion to the packaging material and the metal terminal, the upper limit is preferably about 10 μm or more, more preferably about 15 μm or more. is preferably about 40 μm or less, more preferably about 35 μm or less, and even more preferably about 30 μm or less.

The melting peak temperature of the acid-modified polypropylene layer 12 is not particularly limited, but is preferably 130 to 165°C from the viewpoint of further improving electrolyte resistance while increasing adhesion to packaging materials and metal terminals. degree, more preferably about 140 to 160°C. In addition, in the present invention, the melting peak temperature of the acid-modified polypropylene layer 12 is a value measured similarly to the method of measuring the melting peak temperature of the polypropylene layer 11.

From the viewpoint of improving the sealing strength while suppressing distortion during heat sealing of the adhesive film for metal terminals, in the adhesive film for metal terminals 1 of the present invention, the softening point and acid modification of the polypropylene layer 11 As an absolute value of the difference in softening point of the polypropylene layer 12, the upper limit is preferably about 40°C or less, more preferably about 30°C or less, and even more preferably about 20°C or less, and the lower limit is preferably about 20°C or less. Preferably, it is about 0°C or higher, more preferably about 5°C or higher, and even more preferably about 10°C or higher. The softening points of the polypropylene layer 11 and the acid-modified polypropylene layer 12 are values measured as follows.

(Method for measuring softening point)

Using a scanning thermal microscope (NanoTA manufactured by Anasys), the cantilever model of the thermal probe is EX-AN2-200, and the values are measured under the condition of a temperature increase rate of 5°C/s. In addition, the softening point was set to the peak top temperature.

The adhesive film for metal terminals 1 of the present invention may contain various additives, such as a lubricant, an antioxidant, an ultraviolet absorber, and a light stabilizer, as needed. Additionally, depending on the type and content of the additive, the adhesive film for metal terminal 1 may be discolored.

The content of the lubricant contained in the entire adhesive film 1 for metal terminals is preferably about 0 to 2000 ppm.

(Measurement of lubricant amount)

The content of the lubricant contained in the entire adhesive film for metal terminals 1 is a value measured using a gas chromatograph-mass spectrometer (GC-MS). Specifically, the additives in the adhesive film for metal terminals are extracted into methanol in boiling refluxed methanol, and the obtained methanol extract is analyzed by GC-MS to measure the amount of lubricant contained in the entire adhesive film for metal terminals. do.

The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bis amides, and unsaturated fatty acid bis amides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, and N-stearyl erucic acid amide. there is. Additionally, specific examples of methylol amide include methylol stearic acid amide. Specific examples of saturated fatty acid bis amides include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, and hexamethylene. Bisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, etc. Specific examples of unsaturated fatty acid bis amides include ethylenebis oleic acid amide, ethylenebis erucic acid amide, hexamethylenebis oleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, etc. I can hear it. Specific examples of fatty acid ester amides include stearamideethyl stearate. In addition, specific examples of aromatic bis amides include m-xylylene bis stearic acid amide, m-xylylene bis hydroxystearic acid amide, and N,N'-distearyl isophthalic acid amide. One type of lubricant may be used individually, or two or more types may be used in combination.

Additionally, the adhesive film for metal terminals 1 of the present invention may contain a filler as needed. Since the adhesive film for metal terminals 1 contains a filler, the filler functions as a spacer, making short circuiting between the metal terminal 2 and the barrier layer 33 of the packaging material 3 more effective. It becomes possible to suppress The particle size of the filler is in the range of about 0.1 to 35 μm, preferably about 5.0 to 30 μm, and more preferably about 10 to 25 μm. In addition, when adding a filler to the adhesive film for metal terminals 1, it is preferably included in the polypropylene layer 11 and/or the acid-modified polypropylene layer 12, and the content of the filler is the polypropylene layer. (11) and 100 parts by mass of the resin component forming the acid-modified polypropylene layer 12, respectively, may be about 5 to 30 parts by mass, more preferably about 10 to 20 parts by mass.

As a filler, both inorganic and organic types can be used. Inorganic fillers include, for example, carbon (carbon, graphite), silica, aluminum oxide, barium titanate, iron oxide, silicon carbide, zirconium oxide, zirconium silicate, magnesium oxide, titanium oxide, calcium aluminate, calcium hydroxide, and aluminum hydroxide. , magnesium hydroxide, calcium carbonate, etc. In addition, organic fillers include, for example, fluorine resins, phenol resins, urea resins, epoxy resins, acrylic resins, benzoguanamine-formaldehyde condensates, melamine-formaldehyde condensates, polymethyl methacrylate cross-linked products, and polyethylene cross-linked products. Water, etc. may be mentioned. From the viewpoint of shape stability, rigidity, and content resistance, aluminum oxide, silica, fluororesin, acrylic resin, and benzoguanamine-formaldehyde condensate are preferable, and among these, spherical aluminum oxide and silica are more preferable. As a method of mixing the filler with the resin component forming the polypropylene layer 11 and/or the acid-modified polypropylene layer 12, the two are melt-blended in advance using a Banbury mixer or the like, and the master batch is mixed at a predetermined mixing ratio. method, direct mixing method with the resin component, etc. can be adopted.

In addition, each of the adhesive films 1 for metal terminals may contain a pigment as needed. As the pigment, various inorganic pigments can be used. As a specific example of the pigment, carbon (carbon, graphite) exemplified as the filler above can be preferably exemplified. Carbon (carbon, graphite) is a material generally used inside batteries, and there is no risk of leaching into the electrolyte solution. In addition, a sufficient coloring effect can be obtained with an addition amount that does not significantly impair adhesion, and the apparent melt viscosity of the added resin can be increased since it does not melt due to heat. Additionally, the pressurized portion can be prevented from becoming thin during heat bonding (sealing), thereby preventing a decrease in seal strength.

When adding a pigment to the adhesive film for metal terminals 1, it is preferably contained in the polypropylene layer 11 and/or the acid-modified polypropylene layer 12, and the amount added is, for example, the particle size is about When 0.03 μm carbon black is used, the amount is about 0.05 to 0.3 parts by mass, preferably 0.1 to 0.2 parts, respectively, with respect to 100 parts by mass of the resin component forming the polypropylene layer 11 and the acid-modified polypropylene layer 12. The mass portion can be mentioned. By adding a pigment to the adhesive film 1 for metal terminals, the presence or absence of the adhesive film 1 for metal terminals can be detected by a sensor or inspected by eye. In addition, when adding a filler and a pigment to the polypropylene layer 11 and/or the acid-modified polypropylene layer 12, the filler and the pigment are added to the same polypropylene layer 11 and/or the acid-modified polypropylene layer 12. may be added, but from the viewpoint of not impairing the heat sealability of the adhesive film for metal terminal 1, it is better to add the filler and pigment separately to the polypropylene layer 11 and the acid-modified polypropylene layer 12. desirable.

The adhesive film for metal terminals (1) of the present invention can be manufactured by laminating at least one layer of polypropylene layer and at least one layer of acid-modified polypropylene layer. The method of laminating at least one polypropylene layer and at least one acid-modified polypropylene layer is not particularly limited, and can be performed, for example, by using a thermal lamination method, a sandwich lamination method, or an extrusion lamination method.

The method of interposing the adhesive film for metal terminal 1 between the metal terminal 2 and the packaging material 3 is not particularly limited, and for example, as shown in FIGS. 1 to 3, the metal terminal 2 ) may be wrapped around the metal terminal 2 with the adhesive film 1 for metal terminals in the portion held by the packaging material 3. In addition, although not shown, in the portion where the metal terminal 2 is sandwiched by the packaging material 3, the adhesive film for metal terminal 1 crosses the two metal terminals 2, so that the metal terminal It may be placed on both sides of (2).

[Metal terminal (2)]

The adhesive film for metal terminals (1) of the present invention is used by interposing it between the metal terminal (2) and the packaging material (3). The metal terminal 2 (tab) is a member electrically connected to the electrode (positive or negative electrode) of the battery element 4 and is made of a metal material. The metal material constituting the metal terminal 2 is not particularly limited, and examples include aluminum, nickel, and copper. For example, the metal terminal 2 connected to the positive electrode of a lithium ion battery is usually made of aluminum or the like. Additionally, the metal terminal connected to the negative electrode of the lithium ion battery is usually made of copper, nickel, etc.

The surface of the metal terminal 2 is preferably subjected to chemical conversion treatment from the viewpoint of improving electrolyte resistance. For example, when the metal terminal 2 is formed of aluminum, specific examples of chemical treatment include known methods of forming an acid-resistant film of a phosphate, chromate, fluoride, or triazinethiol compound. Among methods for forming an acid-resistant film, phosphoric acid chromate treatment using a material composed of three components: a phenol resin, a chromium(III) fluoride compound, and phosphoric acid is suitable.

The size of the metal terminal 2 may be set appropriately depending on the size of the battery used, etc. The thickness of the metal terminal 2 is preferably about 50 to 1000 μm, more preferably about 70 to 800 μm. Additionally, the length of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm. Additionally, the width of the metal terminal 2 is preferably about 1 to 200 mm, more preferably about 3 to 150 mm.

[Packaging material (3)]

As the packaging material 3, one may have a laminated structure consisting of a laminated body having at least a base material layer 31, a barrier layer 33, and a heat-sealable resin layer 34 in this order. In Figure 6, as an example of the cross-sectional structure of the packaging material 3, the base layer 31, adhesive layer 32, barrier layer 33, adhesive layer 35, and heat-sealable resin layer 34 are in this order. It shows how they are stacked as shown. The adhesive layer 32 is a layer provided as needed for the purpose of improving the adhesion between the base material layer 31 and the barrier layer 33. Additionally, the adhesive layer 35 is a layer provided as needed for the purpose of improving the adhesion between the barrier layer 33 and the heat-sealable resin layer 34.

In the packaging material 3, the base material layer 31 is the outermost layer, and the heat-sealable resin layer 34 is the innermost layer. When assembling the battery, the heat-sealable resin layers 34 located on the periphery of the battery element 4 are brought into contact with each other and thermally welded, thereby sealing the battery element 4. 1 to 3 show a battery 10 using an embossed type packaging material 3 formed by embossing or the like, but the packaging material 3 may be an unmolded pouch type. Additionally, pouch types include three-way seal, four-way seal, and pillow type, but any type may be used.

[Base layer (31)]

In the packaging material 3, the base material layer 31 is a layer that functions as a base material for the packaging material and is a layer that forms the outermost layer.

The material forming the base layer 31 is not particularly limited as long as it has insulating properties. Materials forming the base layer 31 include, for example, polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluorine resin, polyurethane, silicon resin, phenol resin, polyetherimide, polyimide, and mixtures thereof. or copolymers.

The thickness of the base material layer 31 is, for example, about 10 to 50 μm, preferably about 15 to 30 μm.

[Adhesive layer (32)]

In the packaging material 3, the adhesive layer 32 is a layer disposed on the base material layer 31 as needed in order to provide adhesiveness to the base material layer 31. That is, the adhesive layer 32 is provided between the base material layer 31 and the barrier layer 33 as needed.

The adhesive layer 32 is formed of an adhesive capable of bonding the base material layer 31 and the barrier layer 33. The adhesive used to form the adhesive layer 32 may be a two-liquid curing type adhesive or may be a one-liquid curing type adhesive. Additionally, the adhesive used to form the adhesive layer 32 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melt type, or a heat pressure type.

The thickness of the adhesive layer 32 is, for example, about 2 to 50 μm, preferably about 3 to 25 μm.

[Barrier layer (33)]

In the packaging material, the barrier layer 33 is a layer that has the function of preventing water vapor, oxygen, light, etc. from entering the battery, in addition to improving the strength of the battery packaging material. Specific examples of the metal constituting the barrier layer 33 include aluminum, stainless steel, and titanium, and aluminum is preferred. The barrier layer 33 can be formed of, for example, metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, or a film provided with these vapor deposition films, and is preferably formed of metal foil, and aluminum alloy foil. It is more preferable to form by . From the viewpoint of preventing wrinkles and pinholes from occurring in the barrier layer 33 during the manufacture of battery packaging materials, the barrier layer may be made of, for example, annealed aluminum (JIS H4160:1994 A8021H-O, JIS H4160 :1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O), etc. It is more preferable to form it with soft aluminum alloy foil.

The thickness of the barrier layer 33 is not particularly limited as long as it functions as a barrier layer for water vapor, etc., but can be, for example, about 10 to 50 μm, preferably about 10 to 40 μm.

[Adhesive layer (35)]

In the packaging material 3, the adhesive layer 35 is provided between the barrier layer 33 and the heat-sealable resin layer 34 as necessary in order to firmly adhere the heat-sealable resin layer 34. This is the prepared floor.

The adhesive layer 35 is formed of an adhesive capable of bonding the barrier layer 33 and the heat-sealable resin layer 34. The composition of the adhesive used to form the adhesive layer is not particularly limited, but examples include a resin composition containing acid-modified polyolefin. Examples of the acid-modified polyolefin include those similar to those described for the acid-modified polypropylene layer 12. In addition, polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene may be acid-modified with an unsaturated carboxylic acid or anhydride thereof (for example, those exemplified in the acid-modified polypropylene layer 12). It can be exemplified.

The thickness of the adhesive layer 35 is, for example, about 1 to 40 μm, preferably about 2 to 30 μm.

[Heat-sealable resin layer (34)]

In the packaging material 3, the heat-sealable resin layer 34 corresponds to the innermost layer and is a layer that seals the battery element by heat-sealing the heat-sealable resin layers to each other during battery assembly.

The resin component used in the heat-sealable resin layer 34 is not particularly limited as long as it can be heat-sealed, but examples include polyolefin and acid-modified polyolefin.

Examples of the polyolefin include the same polyethylene as exemplified in the polypropylene layer 11, and polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene. In addition, examples of the acid-modified polyolefin include those similar to those described for the adhesive layer 35.

In addition, the thickness of the heat-sealable resin layer 34 is not particularly limited, but is preferably about 2 to 2000 μm, more preferably about 5 to 1000 μm, and even more preferably about 10 to 500 μm. there is.

2. Battery (10)

The battery 10 of the present invention includes at least a battery element 4 provided with a positive electrode, a negative electrode, and an electrolyte, a packaging material 3 for sealing the battery element 4, and electrically connected to each of the positive electrode and the negative electrode. and is provided with a metal terminal 2 protruding outside the packaging material 3. The battery 10 of the present invention is characterized in that the adhesive film 1 for metal terminals of the present invention is interposed between the metal terminal 2 and the packaging material 3.

Specifically, the battery element 4, which includes at least a positive electrode, a negative electrode, and an electrolyte, is prepared by packaging material 3 in a state in which metal terminals 2 connected to each of the positive electrode and negative electrode protrude outward. The adhesive film for metal terminals 1 is interposed between the metal terminals 2 and the heat-sealable resin layer 34, and the flange portion of the packaging material (heat-sealable resin layer ( 34) is an area in contact with each other, and is covered to form the peripheral portion 3a of the packaging material, and the heat-sealable resin layers 34 of the flange portion are heat-sealed to each other to seal the packaging material 3. A used battery 10 is provided. In addition, when using the packaging material 3 to accommodate the battery element 4, the heat-sealable resin layer 34 of the packaging material 3 is used so that it is on the inside (the surface in contact with the battery element 4). do.

The battery of the present invention may be either a primary battery or a secondary battery, but is preferably a secondary battery. The type of secondary battery is not particularly limited, and includes, for example, lithium ion batteries, lithium ion polymer batteries, lead storage batteries, nickel/hydrogen storage batteries, nickel/cadmium storage batteries, nickel/iron storage batteries, nickel/zinc storage batteries, silver oxide storage batteries, etc. Examples include zinc storage batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are preferred.

In addition, when measuring the thickness of the packaging material, metal terminal, and adhesive film for metal terminals that make up the battery, the portion where the packaging material, adhesive film for metal terminal, and metal terminal are laminated, the desired thickness of the packaging material is Examples of the thickness include about 10 to 65 ㎛, examples of the thickness of the metal terminal include about 50 to 1000 ㎛, and examples of a preferable thickness of the adhesive film for metal terminals include about 30 to 80 ㎛. The sum of the thickness and the preferable thickness of the adhesive film for metal terminals is approximately 40 to 145 μm.

Example

The present invention will be described in detail below by showing examples and comparative examples. However, the present invention is not limited to the examples.

In the examples and comparative examples, measurement of melting peak temperature, measurement of heat shrinkage, measurement of seal strength, measurement of thickness residual ratio, measurement of electrolyte resistance and area ratio of island portion in sea-island structure were evaluated as follows. It was done like this. Each result is shown in Table 1.

(Measurement of melting peak temperature)

Adhesive films for metal terminals were measured using differential scanning calorimetry (DSC). As the device, “DSC-60 Plus” manufactured by Shimadzu Seisakusho was used. In addition, the measurement conditions were that the temperature increase rate was 10°C/min, the temperature measurement range was -50 to 200°C, and an aluminum pan was used as a sample pan.

(Measurement of heat shrinkage rate)

The adhesive film for metal terminals was cut into a size of 50 mm in length (MD) x 4 mm in width (TD) to use as a test piece. Next, the length M (mm) of the test piece was measured with a metal ruler. Next, the longitudinal end of the test piece was fixed to a metal mesh with tape, and the test piece was hung from the metal mesh to hang. In this state, after being placed in an oven heated to 190°C for 120 seconds, the test pieces were taken out by metal mesh and naturally cooled in a room temperature (25°C) environment. Next, the length N (mm) of the test piece naturally cooled to room temperature was measured with a metal ruler. The heat shrinkage rate of the adhesive film for metal terminals was calculated using the following equation.

Heat shrinkage rate (%) = (length N/length M) x 100

(Measurement of seal strength)

As shown in the schematic diagram of FIG. 7, the packaging material 3 was cut into a size of 150 mm in length (MD) x 60 mm in width (TD). Additionally, the adhesive film for metal terminals 1 was cut into a size of 75 mm in length (MD) x 60 mm in width (TD). Additionally, a metal terminal 2 (aluminum plate, length 60 mm, width 25 mm, thickness 0.1 mm) was prepared. Next, as shown in the schematic diagram of FIG. 8, the packaging material 3 was folded in half in the longitudinal direction at the position of the center P of MD with the heat-sealable resin layer on the inside. Next, the adhesive film for metal terminals 1 and the metal terminal 2 (aluminum plate, length 60 mm, width 25 mm, thickness 0.1 mm) are overlapped, and the packaging material is folded in half as shown in the schematic diagram of FIG. 8. It was inserted between (3). At this time, the acid-modified polypropylene layer of the adhesive film for metal terminals 1 was placed in contact with the metal terminal 2. A cross-sectional view seen from the side is shown in Figure 8b. In this state, as shown in the schematic diagram of FIG. 9A, heat sealing is performed from both sides of the packaging material 3 under the conditions of a seal width of 7.0 mm, a seal temperature of 190°C, a surface pressure of 1.0 MPa, and a sealing time of 3 seconds, and the laminate is formed. got it In the heat sealed portion S in Figure 9, the direction of the seal width corresponds to the MD of the packaging material. Next, the width of the heat-sealed portion S (TD of the packaging material) was set to 15 mm, and a sample was cut out from the laminate at the position of the double-dashed line in the schematic diagram of FIG. 9B. The packaging material 3 of the obtained sample and the adhesive film 1 for metal terminals were spaced apart in a 180° direction to the position of the heat-sealed portion S. A cross-sectional view of the sample in this state viewed from the side is shown in Fig. 9C. Next, the seal strength (N/15 mm) was measured using a tensile tester (AG-Xplus manufactured by Shimadzu Seisakusho) under the conditions of a speed of 300 mm/min, a distance between chucks of 50 mm, and a T-shaped peeling method. . At this time, as shown in FIG. 10, in the laminate in which packaging material 3/adhesive film for metal terminal 1/metal terminal 2/packaging material 3 are laminated in that order, “metal terminal Pinch the portion of “adhesive film (1)/metal terminal (2)/packaging material (3)” with the lower chuck, and pinch the packaging material (3) spaced in a 180° direction with the upper chuck, then pack. The material (3) and the adhesive film for metal terminal (1) were peeled and the seal strength was measured.

(Evaluation of electrolyte resistance)

The adhesive film for metal terminals was cut to a size of 15 mm (MD) x 100 mm (TD) to use as a test piece. Next, the test piece was immersed in an electrolyte solution (1M LiPF ₆ solution (ethylene carbonate:dimethyl carbonate:diethyl carbonate = 1:1:1, volume ratio)) and incubated in an oven at 85°C for 24 hours. It was stored. Next, the test piece was taken out, washed with water, and then visually observed. The case in which the interlayers of the test piece were not separated was designated as “A”, and the case in which the interlayers of the test specimen were separated was designated as “C”.

(Measurement of thickness residual rate of adhesive film for metal terminal)

An aluminum plate (pure aluminum, JIS H4160-1994 A1N30H-O) with a length of 60 mm, a width of 25 mm, and a thickness of 100 μm, and the adhesive film for the metal terminal with a length of 70 mm and a width of 5 mm were prepared. Next, the thickness A (μm) of the adhesive film for metal terminals was measured with a micro gauge. Next, the longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal were aligned, and the adhesive film for a metal terminal was overlapped on the center portion of the aluminum plate. Next, prepare two metal plates with a width of 7 mm that are longer than the length of the aluminum plate, and cover the entire surface of the adhesive film for metal terminals, from the top and bottom of the adhesive film for metal terminals, at a temperature of 190°C. , heating and pressurization were performed under the conditions of a surface pressure of 1.27 MPa and a time of 3 seconds to obtain a laminate of an aluminum plate and an adhesive film for metal terminals. Next, the thickness B (μm) of the heated and pressurized portion of the laminate was measured using a micro gauge. The thickness survival rate of the adhesive film for metal terminals was calculated using the following equation. At this time, the thickness B is the sum of one location at the center of the laminate and two locations 10 mm from both ends in the longitudinal direction of the laminate (both ends of the portion where the aluminum plate and the adhesive film for metal terminal are laminated) toward the center. It was taken as the average value of 3 locations.

Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100

<Method for measuring the ratio of the area of the island portion in the chart structure>

The adhesive film for metal terminals was embedded in a thermosetting epoxy resin and cured. A commercially available rotary microtome (UC6 manufactured by LEICA) and a diamond knife were used to produce a cross section in the desired direction (cross section along TD), and then a cross section was prepared at -70°C using a cryomicrotome using liquid nitrogen. It was done. Each embedding resin was stained with ruthenium tetroxide overnight. Since polypropylene expands when dyed, the expanded portion was trimmed with a microtome, and the portion cut to a thickness of about 100 nm and further about 1 to 2 μm was observed as follows. The stained cross section is observed with a field emission scanning electron microscope (e.g., S-4800 TYPE1 manufactured by Hitachi High-Technologies, measurement conditions: 3kV 20mA High WD6mm detector (Upper)) and images are obtained (magnification: 10,000x). acquired. Next, using image processing software that can binarize the image (for example, image analysis software WinROOF (Ver7.4) manufactured by Mitani Shoji), the island portion and the sea portion of the chart structure are divided into two parts for the image. By denaturing, the ratio of the area occupied by the island portion (total area of the island portion/area of the measurement range of the image) was obtained. The specific image processing conditions are as follows. In addition, in this measurement, the island portion is the sea portion. Because it was dyed more, the island part was observed to be brighter than the sea part.

[Image processing conditions]

3x3pix averaging

Binaryization: Automatic binaryization

Isolated point removal: Removes an object or background consisting of 1 pixel.

Delete: Delete particles by obtaining shape characteristic values or density characteristic values (an area of ^0.005㎛2 is recognized as noise)

<Manufacture of adhesive film for metal terminal>

(Example 1)

As the polypropylene layer, a three-layer unstretched polypropylene film (CPP, total) in which random polypropylene layer (6㎛)/block polypropylene layer (38㎛)/random polypropylene layer (6㎛) are laminated in that order. Thickness 50㎛, melting peak temperature 155℃) was prepared. Next, maleic anhydride-modified polypropylene was extruded and laminated on both sides of the unstretched polypropylene film by a lamination method, respectively, acid-modified polypropylene layer (25 ㎛) / polypropylene layer (50 ㎛) / acid-modified. An adhesive film for metal terminals in which polypropylene layers (25㎛) were sequentially laminated was manufactured. The heat shrinkage rate of the obtained adhesive film for metal terminals was measured, and it showed a high value of 83.0%.

(Example 2)

As the polypropylene layer, a three-layer unstretched polypropylene film (CPP, total) in which random polypropylene layer (8㎛)/block polypropylene layer (44㎛)/random polypropylene layer (8㎛) are laminated in that order. Thickness 60㎛, melting peak temperature 155℃) was prepared. Next, maleic anhydride-modified polypropylene was extruded and laminated on both sides of the unstretched polypropylene film by a lamination method, respectively, acid-modified polypropylene layer (20 ㎛) / polypropylene layer (60 ㎛) / acid-modified. An adhesive film for metal terminals in which polypropylene layers (20㎛) were sequentially laminated was manufactured. The heat shrinkage rate of the obtained adhesive film for metal terminals was measured, and it showed a high value of 81.3%.

(Example 3)

As the polypropylene layer, a three-layer unstretched polypropylene film (CPP, total) in which random polypropylene layer (6㎛)/block polypropylene layer (38㎛)/random polypropylene layer (6㎛) are laminated in that order. Thickness 50㎛, melting peak temperature 155℃) was prepared. Next, maleic anhydride-modified polypropylene is extruded and laminated on one side of the unstretched polypropylene film by a lamination method, and a metal terminal is formed with the acid-modified polypropylene layer (16 ㎛)/polypropylene layer (50 ㎛) laminated. An adhesive film was prepared. The heat shrinkage rate of the obtained adhesive film for metal terminals was measured and found to be as high as 80.1%.

(Example 4)

As the polypropylene layer, a three-layer unstretched polypropylene film (CPP, total) in which random polypropylene layer (4㎛)/block polypropylene layer (22㎛)/random polypropylene layer (4㎛) are laminated in that order. Thickness 30㎛, melting peak temperature 155℃) was prepared. Next, maleic anhydride-modified polypropylene is extruded and laminated on one side of the unstretched polypropylene film by a lamination method, and a metal terminal is formed with the acid-modified polypropylene layer (36 ㎛)/polypropylene layer (30 ㎛) laminated. An adhesive film was prepared. The heat shrinkage rate of the obtained adhesive film for metal terminals was measured, and it showed a high value of 88.1%.

(Example 5)

As the polypropylene layer, a three-layer unstretched polypropylene film (CPP, total) in which random polypropylene layer (4㎛)/block polypropylene layer (22㎛)/random polypropylene layer (4㎛) are laminated in that order. Thickness 30㎛, melting peak temperature 155℃) was prepared. Next, maleic anhydride-modified polypropylene was extruded and laminated on both sides of the unstretched polypropylene film by a lamination method, respectively, acid-modified polypropylene layer (18 ㎛) / polypropylene layer (30 ㎛) / acid-modified. An adhesive film for metal terminals in which polypropylene layers (18㎛) were sequentially laminated was manufactured. The heat shrinkage rate of the obtained adhesive film for metal terminals was measured, and it showed a high value of 88.1%.

(Example 6)

As a polypropylene layer, an unstretched polypropylene film (CPP, total thickness of 60 μm, melting peak temperature of 159°C) with a block polypropylene layer (60 μm) was prepared. Next, maleic anhydride-modified polypropylene was extruded and laminated on both sides of the unstretched polypropylene film by a lamination method, respectively, acid-modified polypropylene layer (20 ㎛) / polypropylene layer (60 ㎛) / acid-modified. An adhesive film for metal terminals in which polypropylene layers (20㎛) were sequentially laminated was manufactured. The heat shrinkage rate of the obtained adhesive film for metal terminals was measured and found to be as high as 81.7%.

(Example 7)

As the polypropylene layer, a three-layer unstretched polypropylene film (CPP, total) in which random polypropylene layer (4㎛)/block polypropylene layer (22㎛)/random polypropylene layer (4㎛) are laminated in that order. Thickness 30㎛, melting peak temperature 155℃) was prepared. Next, maleic anhydride-modified polypropylene is extruded and laminated on both sides of the unstretched polypropylene film by a lamination method, and acid-modified polypropylene layer (16 ㎛) / polypropylene layer (30 ㎛) / acid-modified polypropylene (16㎛) laminated adhesive film for metal terminals was manufactured. The heat shrinkage rate of the obtained adhesive film for metal terminals was measured, and it showed a high value of 88.7%.

(Comparative Example 1)

As the polypropylene layer, a three-layer unstretched polypropylene film (CPP, total) in which random polypropylene layer (4㎛)/block polypropylene layer (22㎛)/random polypropylene layer (4㎛) are laminated in that order. Thickness 30㎛, melting peak temperature 155℃) was prepared. Next, maleic anhydride-modified polypropylene was extruded and laminated on both sides of the unstretched polypropylene film, respectively, by a lamination method, and acid-modified polypropylene layer (35 ㎛)/polypropylene layer (30 ㎛)/acid-modified An adhesive film for metal terminals in which polypropylene layers (35㎛) were sequentially laminated was manufactured.

(Comparative Example 2)

As the polypropylene layer, a three-layer unstretched polypropylene film (CPP, total) in which random polypropylene layer (3㎛)/block polypropylene layer (3㎛)/random polypropylene layer (19㎛) are laminated in that order. Thickness 25㎛, melting peak temperature 155℃) was prepared. Next, maleic anhydride-modified polypropylene is extruded and laminated on one side of the unstretched polypropylene film by a lamination method, and a metal terminal is formed with the acid-modified polypropylene layer (41 ㎛) and the polypropylene layer (25 ㎛) laminated. An adhesive film was prepared.

(Comparative Example 3)

As a polypropylene layer, a stretched polypropylene film (OPP, homopolypropylene, thickness 50 μm, melting peak temperature 165°C) was prepared. Next, maleic anhydride-modified polypropylene is extruded and laminated on both sides of the stretched polypropylene film, respectively, by a lamination method, and acid-modified polypropylene layer (25 ㎛) / polypropylene layer (50 ㎛) / acid-modified poly An adhesive film for metal terminals in which propylene layers (25㎛) were sequentially laminated was manufactured.

When cross-sections of the unstretched polypropylene layers used in Examples 1 to 5 and Comparative Examples 1 and 2 were stained with ruthenium tetroxide (RuO ₄ ) and observed through scanning electron micrographs, a sea-island structure was observed. On the other hand, when the stretched polypropylene layer used in Comparative Example 3 was observed in the same manner, no sea-island structure was observed.

(Manufacture of packaging materials)

An aluminum foil (40 μm thick) was prepared on both sides by chemical conversion treatment (phosphoric acid chromate treatment) with a chemical treatment liquid consisting of three components: phenol resin, chromium fluoride (trivalent) compound, and phosphoric acid. Next, one side of this aluminum foil and a biaxially stretched nylon film (thickness 25 μm) were laminated through a urethane-based adhesive. Next, the other side of the aluminum foil and an unstretched polypropylene film (30 μm thick) were sandwich laminated with acid-modified polypropylene resin (15 μm thick, polypropylene graft-modified with unsaturated carboxylic acid), Heating to a temperature above the softening point of the acid-modified polypropylene resin with hot air, biaxially stretched nylon film (25㎛) / aluminum foil (thickness 40㎛) / acid-modified polypropylene resin (thickness 15㎛) / unstretched polypropylene film. (15㎛) sequentially laminated packaging material was manufactured. Using the obtained packaging material, the above-described seal strength measurements were performed.

In Table 1, PP means polypropylene and PPa means acid-modified polypropylene.

As shown in Table 1, it is composed of a laminate including at least one polypropylene layer and at least one acid-modified polypropylene layer, and the acid-modified polypropylene layer is at least one layer of the adhesive film for metal terminals. It constitutes the surface layer on one side, and the polypropylene layer has a sea-island structure when the cross-section is observed with a scanning electron microscope photograph, and when the total thickness of the acid-modified polypropylene layer is assumed to be 1, the polypropylene layer The adhesive films for metal terminals of Examples 1 to 5, in which the total thickness of the layers is within the range of 0.7 to 3.5, all have high sealing strength (i.e., adhesion) with the packaging material and the metal terminal, and are also excellent in electrolyte solution resistance. You can see that it does. On the other hand, the metals of Comparative Examples 1 and 2 have the polypropylene layer having the above-described sea-island structure, but the total thickness of the acid-modified polypropylene layer is outside the range of 0.7 to 3.5 when the total thickness of the acid-modified polypropylene layer is 1. The adhesive film for terminals had poor adhesion to packaging materials and metal terminals. In addition, although it satisfies the range, the adhesive film for metal terminals of Comparative Example 3, which does not have the above-described sea-island structure in the polypropylene layer, is inferior in adhesion to the packaging material and metal terminal and in electrolyte resistance. there was. In addition, in Examples 1 to 7, when the island area was measured by binarization for the sea-island structure of the polypropylene layer, all of them had a large value of 28.0% or more, and also for the acid-modified polypropylene layer. , it had a large value of more than 24.5%. On the other hand, in Comparative Example 3, when the island area was measured by binarization for the sea-island structure of the polypropylene layer, the ratio of the area was a very low value of 1.57%, and it did not substantially have a sea-island structure. It has been confirmed that this is not the case.

1: Adhesive film for metal terminals
2: Metal terminal
3: Packaging materials
3a: Periphery of packaging material
4: Battery element
10: battery
11: Polypropylene layer
12: Acid-modified polypropylene layer
31: base layer
32: adhesive layer
33: barrier layer
34: Heat-sealable resin layer
35: Adhesive layer
P: center
S: Heat sealed part

Claims (35)

An adhesive film for metal terminals interposed between a metal terminal electrically connected to an electrode of a battery element and a packaging material that seals the battery element,
The adhesive film for metal terminals is composed of a laminate including at least one polypropylene layer and at least one acid-modified polypropylene layer,
The acid-modified polypropylene layer constitutes a surface layer on at least one side of the adhesive film for metal terminals,
When the polypropylene layer or the acid-modified polypropylene layer is observed in cross section using an electron micrograph, a sea-island structure is observed,
In the sea-island structure of the polypropylene layer or the acid-modified polypropylene layer, the ratio of the area of the island portion is 20% or more and 50% or less,
An adhesive film for metal terminals wherein, when the total thickness of the acid-modified polypropylene layers is set to 1, the total thickness of the polypropylene layers is within the range of 0.7 to 3.5. According to paragraph 1,
The polypropylene layer is an adhesive film for metal terminals containing block polypropylene. According to claim 1 or 2,
An adhesive film for metal terminals, wherein the polypropylene layer is made of unstretched polypropylene. According to claim 1 or 2,
The polypropylene layer is an adhesive film for metal terminals in which a layer made of random polypropylene, a layer made of block polypropylene, and a layer made of random polypropylene are laminated in this order. According to paragraph 3,
The polypropylene layer is an adhesive film for metal terminals in which a layer made of random polypropylene, a layer made of block polypropylene, and a layer made of random polypropylene are laminated in this order. According to claim 1 or 2,
An adhesive film for metal terminals in which a melting peak is observed in the range of 150°C or higher and 165°C or lower when the adhesive film for metal terminals is measured with a differential scanning calorimeter. According to paragraph 3,
An adhesive film for metal terminals in which a melting peak is observed in the range of 150°C or higher and 165°C or lower when the adhesive film for metal terminals is measured with a differential scanning calorimeter. According to paragraph 4,
An adhesive film for metal terminals in which a melting peak is observed in the range of 150°C or higher and 165°C or lower when the adhesive film for metal terminals is measured with a differential scanning calorimeter. According to clause 5,
An adhesive film for metal terminals in which a melting peak is observed in the range of 150°C or higher and 165°C or lower when the adhesive film for metal terminals is measured with a differential scanning calorimeter. According to claim 1 or 2,
An adhesive film for metal terminals, wherein the thickness residual ratio of the adhesive film for metal terminals measured by the following measurement method is 50% or more and 90% or less.
An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.
Measure the thickness A (μm) of the adhesive film for metal terminals.
The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.
Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.
The thickness B (μm) of the heated and pressurized portion of the laminate is measured.
The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.
Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100 According to paragraph 3,
An adhesive film for metal terminals, wherein the thickness residual ratio of the adhesive film for metal terminals, measured by the following measurement method, is 50% or more and 90% or less.
An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.
Measure the thickness A (μm) of the adhesive film for metal terminals.
The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.
Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.
The thickness B (μm) of the heated and pressurized portion of the laminate is measured.
The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.
Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100 According to paragraph 4,
An adhesive film for metal terminals, wherein the thickness residual ratio of the adhesive film for metal terminals, measured by the following measurement method, is 50% or more and 90% or less.
An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.
Measure the thickness A (μm) of the adhesive film for metal terminals.
The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.
Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.
The thickness B (μm) of the heated and pressurized portion of the laminate is measured.
The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.
Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100 According to clause 5,
An adhesive film for metal terminals, wherein the thickness residual ratio of the adhesive film for metal terminals, measured by the following measurement method, is 50% or more and 90% or less.
An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.
Measure the thickness A (μm) of the adhesive film for metal terminals.
The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.
Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.
The thickness B (μm) of the heated and pressurized portion of the laminate is measured.
The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.
Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100 According to clause 6,
An adhesive film for metal terminals, wherein the thickness residual ratio of the adhesive film for metal terminals, measured by the following measurement method, is 50% or more and 90% or less.
An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.
Measure the thickness A (μm) of the adhesive film for metal terminals.
The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.
Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.
The thickness B (μm) of the heated and pressurized portion of the laminate is measured.
The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.
Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100 In clause 7,
An adhesive film for metal terminals, wherein the thickness residual ratio of the adhesive film for metal terminals measured by the following measurement method is 50% or more and 90% or less.
An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.
Measure the thickness A (μm) of the adhesive film for metal terminals.
The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.
Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.
The thickness B (μm) of the heated and pressurized portion of the laminate is measured.
The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.
Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100 According to clause 8,
An adhesive film for metal terminals, wherein the thickness residual ratio of the adhesive film for metal terminals, measured by the following measurement method, is 50% or more and 90% or less.
An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.
Measure the thickness A (μm) of the adhesive film for metal terminals.
The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.
Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.
The thickness B (μm) of the heated and pressurized portion of the laminate is measured.
The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.
Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100 According to clause 9,
An adhesive film for metal terminals, wherein the thickness residual ratio of the adhesive film for metal terminals, measured by the following measurement method, is 50% or more and 90% or less.
An aluminum plate with a thickness of 100 μm and the adhesive film for the metal terminal are prepared.
Measure the thickness A (μm) of the adhesive film for metal terminals.
The longitudinal direction and the width direction of the aluminum plate and the adhesive film for a metal terminal are aligned, and the adhesive film for a metal terminal is overlapped on the center portion of the aluminum plate.
Prepare two metal plates with a width of 7 mm longer than the length of the aluminum plate, cover the entire surface of the adhesive film for metal terminals, and apply a temperature of 190 degrees from the top and bottom of the aluminum plate and the adhesive film for metal terminals. Heating and pressurization are performed on the metal plate under conditions of ℃, surface pressure of 1.27 MPa, and time of 3 seconds to obtain a laminate of the aluminum plate and the adhesive film for metal terminals.
The thickness B (μm) of the heated and pressurized portion of the laminate is measured.
The thickness survival rate of the adhesive film for metal terminals is calculated using the following equation.
Thickness residual rate of adhesive film for metal terminal (%) = (thickness B - 100) / thickness A × 100 According to claim 1 or 2,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to paragraph 3,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to paragraph 4,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 5,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 6,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. In clause 7,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 8,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 9,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 10,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 11,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 12,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 13,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 14,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 15,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 16,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to clause 17,
The adhesive film for metal terminals has a heat shrinkage rate of 70 to 90% in the flow direction of the adhesive film for metal terminals. According to claim 1 or 2,
The packaging material is constructed from a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order,
An adhesive film for a metal terminal, wherein the adhesive film for a metal terminal is interposed between the heat-sealable resin layer and the metal terminal. At least, a battery element having a positive electrode, a negative electrode, and an electrolyte, a packaging material for sealing the battery element, and a metal terminal electrically connected to each of the positive electrode and the negative electrode and protruding to the outside of the packaging material. It is battery,
A battery comprising the adhesive film for metal terminals according to claim 1 or 2 interposed between the metal terminal and the packaging material.