KR20150105200A - Insulating film for sealing tab and electrochemical device - Google Patents

Abstract

An insulating film (1) for sealing a tab comprises at least a base resin layer (2) composed of a resin composition containing 70 mass% to 99 mass% of acid-modified polypropylene, and 1 mass% to 30 mass% of a thermoplastic elastomer, wherein a fusing point of the resin composition is above 155°C, and MFR of the resin composition is below 10g/10 minutes. Accordingly, provided is an insulating film for sealing a tap, capable of sufficiently maintaining a sealing state through an insulating film for sealing a tap in the case of elevating the internal pressure by comprising the same.

Description

TECHNICAL FIELD [0001] The present invention relates to an insulating film for tap sealing and an electrochemical device,

The present invention relates to an insulating film for tap sealing used in an electrochemical device such as a lithium ion secondary battery and an electric double layer capacitor, and an electrochemical device constructed using the insulating film.

In the present specification, the term " MFR " means MFR (melt flow rate) measured under the conditions of a temperature of 230 DEG C and a load of 2.16 kg in accordance with JIS K7210-1999.

In the present specification, the term "melting point" refers to a melting point measured at a heating rate of 10 ° C / minute using a differential scanning calorimeter in accordance with JIS K7121-1987 "Method of measuring transition temperature of plastic" Peak temperature (melting point).

A laminate type electrochemical device used as a thin type battery is a laminate type electrochemical device used as a thin type battery in which a power generation element including an electrode and an electrolyte is received in a wrapping wrap film and a part of a lead terminal connected to the power generation element is drawn out to the outside, (Heat seal) of the power generation element is enclosed with the power generation element.

The pair of lead terminals in the electrochemical device may be formed by piercing the inner surface layer of the cover film during the heat seal and coming into contact with the metal foil in the intermediate layer to be short-circuited.

Therefore, in order to prevent such short-circuiting, a position corresponding to the seal portion of the cover film at the lead terminal is covered with a sealing insulating film. More specifically, it has been proposed to cover portions of the positive electrode lead terminal and the negative electrode lead terminal corresponding to the seal portion with a sealing film of a thermally adhesive synthetic resin having an insulating property in advance (see Patent Documents 1 to 4).

Japanese Patent Application Laid-Open No. 2008-192451 Japanese Patent Application Laid-Open No. 2003-007265 Japanese Patent Application Laid-Open No. 2010-245000 Japanese Patent Application Laid-Open No. 2009-224218

However, in a lithium ion secondary battery or the like, gas is liable to be generated in the battery main body when overcharged or overcharged, and therefore, the gas gradually accumulates in the inner space covered with the casing and the inner pressure inside the casing is increased have. However, in the above-described conventional sealing insulating film, when the internal pressure is increased as described above, the seal portion of the lead terminal is not necessarily sufficiently sealed.

The present invention has been made in view of such a technical background, and an object of the present invention is to provide an insulating film for tap sealing and an electrochemical device which can sufficiently maintain the sealed state through the sealing insulating film even when the internal pressure is increased.

In order to achieve the above object, the present invention provides the following means.

[1] A resin composition comprising at least a base resin layer composed of a resin composition containing 70% by mass to 99% by mass of an acid denaturing polypropylene and 1% by mass to 30% by mass of a thermoplastic elastomer,

Wherein the melting point of the resin composition is 155 占 폚 or higher and the MFR of the resin composition is 10 g / 10 minutes or less.

[2] A resin composition comprising a resin composition comprising 70% by mass to 99% by mass of a first resin component comprising an acid-modified polypropylene and an acid-unmodified polypropylene, and 1% by mass to 30% by mass of a thermoplastic elastomer At least a resin layer,

Wherein the melting point of the resin composition is 155 占 폚 or higher and the MFR of the resin composition is 10 g / 10 minutes or less.

[3] The insulating film has a structure in which an outer resin layer is laminated on a surface facing the jacket material in the base resin layer, and an inner resin layer is laminated on a tab-side surface in the base resin layer, The insulating film for tap sealing according to the above 1 or 2, wherein the inner resin layer contains an acid-modified polypropylene and / or an acid-unmodified polypropylene, and the inner resin layer contains an acid-modified polypropylene.

[4] The method according to any one of [1] to [4], wherein the outer resin layer has a melting point of 130 ° C. to 140 ° C. and the inner resin layer has a melting point of 130 ° C. to 140 ° C.,

The insulating film for tap sealing according to item 3, wherein the melting point of the base resin layer is 25 占 폚 or more higher than the melting point of the outer resin layer and 25 占 폚 or more higher than the melting point of the inner resin layer.

[5] The insulating film for tap sealing according to the above 4, wherein the melting point of the base resin layer is 25 ° C to 45 ° C higher than the melting point of the outer resin layer and 25 ° C to 45 ° C higher than the melting point of the inner resin layer.

[6] The insulating film has a structure in which an outer resin layer is laminated on a side of a casing material side in the base resin layer, and an inner resin layer is laminated on a side of a tab side of the base resin layer,

Wherein the outer resin layer comprises a resin composition having a melting point of less than 155 占 폚 containing 70% by mass to 99% by mass of an acid-modified polypropylene and 1% by mass to 30% by mass of a thermoplastic elastomer,

Wherein the inner resin layer comprises a resin composition containing 70% by mass to 99% by mass of an acid-modified polypropylene and 1% by mass to 30% by mass of a thermoplastic elastomer and having a melting point of less than 155 ° C Insulation film for tap sealing.

[7] The insulating film has a structure in which an outer resin layer is laminated on the side of the casing material in the base resin layer, and an inner resin layer is laminated on the side of the tab resin in the base resin layer,

Wherein the outer resin layer contains a first resin component comprising 70% by mass to 99% by mass of a first resin component comprising acid-modified polypropylene and an acid-unmodified polypropylene, and 1% by mass to 30% by mass of a thermoplastic elastomer Lt; RTI ID = 0.0 > 155 C, < / RTI &

Wherein the inner resin layer contains a first resin component comprising 70% by mass to 99% by mass of a first resin component comprising an acid-modified polypropylene and an acid-unmodified polypropylene, and 1% by mass to 30% by mass of a thermoplastic elastomer The insulating film for tap sealing according to the above 1 or 2, which is made of a resin composition having a temperature of less than 155 占 폚.

[8] The insulating film for tap sealing according to any one of items 1 to 7, wherein the thermoplastic elastomer has a melting point of 80 ° C. or less and the MFR of the thermoplastic elastomer is 5 g / 10 min or less.

[9] The insulating film for tap-sealing according to any one of items 1 to 8, wherein the thermoplastic elastomer is one or two kinds of resins selected from the group consisting of ethylene-propylene rubber and ethylene-propylene-butene rubber.

[10] An electrochemical device comprising the insulating film for tap-sealing according to any one of the items 1 to 9.

[11]

An electrochemical device accommodated in the casing,

Wherein an inner end portion of the tab is electrically connected to the electrochemical device and an outer end portion of the tab is disposed outside the case,

Characterized in that the seal portion of the casing is joined to both surfaces of the tab in a state in which both surfaces of the tab are sandwiched by the seal portion of the casing using the tap sealing insulating film described in any one of the items 1 to 9, Lt; / RTI >

The invention of [1] includes a base resin layer composed of a resin composition containing 70% by mass to 99% by mass of an acid-modified polypropylene and 1% by mass to 30% by mass of a thermoplastic elastomer, The resin layer contains an acid-modified polypropylene at a content ratio within the specific range described above, thereby securing an adhesive force (an adhesive force to the metal tab and an adhesive strength to the exterior material), and a thermoplastic elastomer Thus, even when stress is concentrated on the thermoplastic elastomer component when a force is applied to the tab-sealing insulating film due to an increase in internal pressure, cohesion failure in the base resin layer can be prevented from occurring, A satisfactory sealing state through the film can be sufficiently maintained.

Further, since the melting point of the base resin layer is 155 占 폚 or higher, the base resin layer is hardly crushed at the time of the actual bonding, thereby ensuring sufficient insulating property. In addition, since the MFR of the resin composition is 10 g / 10 min or less, the base resin layer is hardly crushed at the time of the actual bonding, and more sufficient insulating property can be secured.

In the invention of [2], a resin comprising 70% by mass to 99% by mass of a first resin component composed of an acid-modified polypropylene and an acid-unmodified polypropylene, and 1% by mass to 30% by mass of a thermoplastic elastomer (The adhesive force to the metal tab and the adhesive force to the casing) can be ensured by containing the first resin component at the content ratio of the above-mentioned specific range, and In addition, even when stress is concentrated on the thermoplastic elastomer component when a force is applied to the tab-sealing insulating film due to a rise in internal pressure or the like due to the inclusion of the thermoplastic elastomer in the content range of the specific range, It is possible to prevent the occurrence of cohesive failure, and it is possible to sufficiently maintain a good sealing state through the tap-sealing insulating film .

Further, since the melting point of the base resin layer is 155 占 폚 or higher, the base resin layer is hardly collapsed at the time of the actual bonding, thereby ensuring sufficient insulating property. In addition, since the MFR of the resin composition is 10 g / 10 min or less, the base resin layer is hardly crushed at the time of the actual bonding, and more sufficient insulating property can be secured.

In the invention of [3], since the outer resin layer laminated on the face side of the base resin layer contains the acid-modified polypropylene and / or the polypropylene which is not modified with an acid, And the inner resin layer laminated on the tab-side surface of the base resin layer contains the acid-modified polypropylene, so that the inner resin layer is sufficiently thermally adhered to the metal tab . In this configuration, since the base resin layer of the intermediate layer has a melting point of 155 캜 or higher, the base resin layer is hardly crushed at the time of the actual bonding, thereby ensuring sufficient insulating property.

In the invention of [4], the outer resin layer has a melting point of 130 ° C to 140 ° C, the melting point of the inner resin layer is 130 ° C to 140 ° C, the melting point of the base resin layer is 25 ° C or more higher than the melting point of the outer resin layer , And a melting point of the inner resin layer is 25 DEG C or more higher than the melting point of the inner resin layer, sufficient seal bonding strength can be ensured and sufficient insulation can be ensured (sufficient sealability and sufficient insulation can be ensured) .

In the invention of [5], the melting point of the base resin layer is 25 占 폚 to 45 占 폚 higher than the melting point of the outer resin layer and is higher than the melting point of the inner resin layer by 25 占 폚 to 45 占 폚, , There is an advantage that more sufficient properties (sealing property) and more sufficient insulating property can be secured.

In the inventions of [6] and [7], the outer resin layer laminated on the face side of the base resin layer is composed of 70% by mass to 99% by mass of the acid denatured polypropylene and 1% by mass to 30% by mass of the thermoplastic elastomer %, And the inner resin layer laminated on the tab-side surface of the base resin layer is a resin composition having a melting point of less than 155 DEG C, Is a composition comprising a resin composition having a melting point of less than 155 캜 and containing 70% by mass to 99% by mass of modified polypropylene and 1% by mass to 30% by mass of thermoplastic elastomer, Sufficient heat bonding can be performed. Further, since all of the base resin layer, the outer resin layer and the inner resin layer contains 1 mass% to 30 mass% of the thermoplastic elastomer, flexibility is imparted to the entirety of the insulating tap film, Whitening) can be reduced.

In the invention of [8], since the melting point of the thermoplastic elastomer is 80 ° C or less, the adhesion to the metal tab can be further improved. In addition, since the MFR of the thermoplastic elastomer is 5 g / 10 min or less, the thermoplastic elastomer among the acid-modified polypropylene (or the first resin component) in the base resin layer has an independent spherical shape (Dispersed phase) of a spherical dispersed phase is formed. Thus, there is an advantage that a sufficient yarn strength can be ensured even in an incompatible resin composition.

In the invention of [9], since the thermoplastic elastomer is one or two kinds of resins selected from the group consisting of ethylene-propylene rubber and ethylene-propylene-butene rubber, The stress can be sufficiently absorbed by the thermoplastic elastomer component even if a force is applied to the base resin layer so that the occurrence of cohesive failure in the base resin layer can be prevented and thereby a good sealing state through the tap- It can be maintained sufficiently.

In the inventions (electrochemical devices) of [10] and [11], even when stress is concentrated on the thermoplastic elastomer component when a force is applied to the tab-sealing insulating film due to an increase in internal pressure or the like, The occurrence of cohesive failure can be prevented, and a satisfactory sealed state can be sufficiently maintained through the insulating film for tap sealing. Further, since the melting point of the base resin layer of the tap-sealing insulating film is 155 占 폚 or higher, the base resin layer is hardly crushed at the time of the actual bonding, thereby ensuring sufficient insulating property. In addition, since the base resin layer of the tap-sealing insulating film has an MFR of 10 g / 10 min or less, the base resin layer is hardly crushed at the time of the actual bonding, and more sufficient insulating property can be secured.

1 is a cross-sectional view showing an embodiment of an insulation film for tap sealing according to the present invention.
Fig. 2 is a perspective view showing a state in which an electrochemical element is accommodated in a casing material processed into a bag shape; Fig.
Fig. 3 is a cross-sectional view (cross-sectional view at the actual part) showing one embodiment of an electrochemical device constructed using the tap-sealing insulating film according to the present invention. Fig.
4 is a graph showing an SD curve in the actual strength measurement of the tap-sealing insulation film obtained in Example 1. Fig.
5 is a graph showing an SD curve in the actual strength measurement of the tap-sealing insulation film obtained in Comparative Example 1. Fig.

The tap-sealing insulation film (1) according to the present invention comprises a base resin layer (1) comprising a resin composition containing 70% by mass to 99% by mass of an acid-modified polypropylene and 1% by mass to 30% by mass of a thermoplastic elastomer 2), wherein the melting point of the resin composition is 155 占 폚 or higher and the MFR of the resin composition is 10 g / 10 min or less.

The insulating film for tap sealing (1) according to the present invention comprises 70% by mass to 99% by mass of a first resin component comprising an acid-modified polypropylene and an acid-unmodified polypropylene, 1% by mass of a thermoplastic elastomer, To 30% by mass of the resin composition, wherein the melting point of the resin composition is 155 占 폚 or higher and the MFR of the resin composition is 10 g / 10 minutes or less.

In the present invention, it is preferable that the base resin layer (2) contains 70% by mass to 99% by mass of the acid-modified polypropylene or 70% by mass of the first resin component comprising polypropylene which is not modified with the acid- % To 99% by mass of the thermoplastic elastomer composition, it is possible to secure the adhesive force (the adhesive force to the metal tab and the adhesive strength to the casing) and to contain the thermoplastic elastomer in an amount of 1% by mass to 30% Even when stress is concentrated on the thermoplastic elastomer component dispersed in the acid-modified polypropylene or in the first resin component when a force is applied to the tab-sealing insulating film due to an increase in internal pressure or the like, It is possible to prevent the occurrence of cohesive failure in the case where the tab-sealing insulating film 1 is used.

In the present invention, usually, the thermoplastic elastomer forms a phase-separated structure in the acid-modified polypropylene, or the thermoplastic elastomer forms a phase-separated structure in the first resin component, It is possible to minimize the propagation of the stress in succession to the thermoplastic elastomer phase of the phase separation structure when the stress is concentrated on the thermoplastic elastomer component in the base resin layer 2, It is possible to sufficiently prevent the occurrence of cohesive failure of the sealing insulating film 1 and to provide the sealing insulating film 1 having a stable sealing strength.

Further, in the phase separation structure, thermoplastic elastomer phases are phase-separated in a substantially plate-like shape, and it is possible to suppress the propagation of the stress successively between the thermoplastic elastomer phases of the substantially plate- It is presumed that the occurrence of cohesive failure can be prevented. It is considered that the thermoplastic elastomer image in the substantially plate-like shape is diffused in a substantially parallel shape on the surface of the sealing insulating film 1.

Further, since the melting point of the resin composition (base resin layer (2)) is not less than 155 占 폚, the base resin layer (2) is not liable to collapse at the time of actual bonding, thereby ensuring sufficient insulating property. The melting point of the resin composition (base resin layer (2)) is preferably in the range of 155 占 폚 to 175 占 폚.

Further, since the MFR of the resin composition (base resin layer (2)) is 10 g / 10 min or less, the base resin layer (2) is hardly collapsed at the time of the actual bonding, and more sufficient insulating property can be ensured. The MFR of the resin composition (base resin layer (2)) is preferably in the range of 0.2 g / 10 min to 10 g / 10 min. When it is 0.2 g / 10 min or more, the realness can be improved. In particular, the MFR of the resin composition (base resin layer (2)) is particularly preferably in the range of 0.5 g / 10 min to 7 g / 10 min.

When the content of the thermoplastic elastomer in the base resin layer exceeds 30% by mass, when a force is applied to the tab-sealing insulating film due to an increase in internal pressure or the like, a satisfactory sealing state is ensured through the tap- I can not. If the content of the thermoplastic elastomer in the base resin layer is less than 1 mass%, the effect due to the thermoplastic elastomer component can not be sufficiently obtained. Therefore, a force is applied to the tab-sealing insulating film The adhesiveness to the tap metal is lowered when the tape is sealed and a satisfactory sealed state can not be ensured through the tap sealing insulating film. The content of the thermoplastic elastomer in the base resin layer (2) is preferably in the range of 5 mass% to 25 mass%.

The tab-sealing insulating film 1 according to the present invention has a structure including at least the base resin layer 2 of the specific constitution described above and a constitution comprising only the base resin layer 2 of the specific constitution (base resin layer 2 ) Or a laminated structure in which a resin layer is laminated on at least one of the surfaces of the base resin layer 2 having the specific structure.

1 and 3, the outer resin layer 3 is laminated on the surface of the base resin layer 2 on the side of the casing member 23, and the base resin layer 2 , The inner resin layer 4 is laminated on the surface of the tab 21 (22) side of the outer resin layer 3, and the outer resin layer 3 is formed of the "acid denatured polypropylene" and / Polypropylene ", and the inner resin layer (4) contains an acid-modified polypropylene.

The melting point of the outer resin layer is 130 占 폚 to 140 占 폚 and the melting point of the inner resin layer is 130 占 폚 to 140 占 폚 and the melting point of the base resin layer 2 is 25 占° C. or more and higher than the melting point of the inner resin layer 4 by 25 ° C. or more, a sufficient seal strength can be ensured and sufficient insulation can be ensured (ie, sufficient physical properties and sufficient insulating properties Can be achieved.

The melting point of the base resin layer 2 is preferably 25 占 폚 to 45 占 폚 higher than the melting point of the outer resin layer 3 and 25 占 폚 to 45 占 폚 higher than the melting point of the inner resin layer 4, When the melting point difference of both is 45 占 폚 or less, it is possible to secure more sufficient properties (sealing property) and more sufficient insulating property.

Alternatively, as the lamination structure, the following structure may be adopted. That is, as shown in Figs. 1 and 3, the outer resin layer 3 is laminated on the surface of the base resin layer 2 on the side of the facing material 23, and the tabs Wherein the outer resin layer (3) is composed of 70% by mass to 99% by mass of the acid-modified polypropylene and 1% by mass of the thermoplastic elastomer Wherein the inner resin layer (4) comprises 70% by mass to 99% by mass of an acid-modified polypropylene and 1% by mass of a thermoplastic elastomer, wherein the inner resin layer (4) By mass to 30% by mass, and a melting point of less than 155 占 폚.

Alternatively, as shown in Figs. 1 and 3, the outer resin layer 3 is laminated on the surface of the base resin layer 2 on the side of the facing material 23, and the outer resin layer 3 is laminated on the surface of the base resin layer 2 The inner resin layer 4 is laminated on the surface on the side of the tabs 21 and 22 so that the outer resin layer 3 is composed of an acid-modified polypropylene and an acid- Wherein the inner resin layer (4) comprises a resin composition having a melting point of less than 155 캜 and containing 70% by mass to 99% by mass of the first resin component and 1% by mass to 30% by mass of the thermoplastic elastomer, Acid-modified polypropylene " and " acid-unmodified polypropylene ", and a thermoplastic elastomer in an amount of 1 to 30% by mass, and a melting point of less than 155 캜 Of the resin composition.

In the present invention, the acid-modified polypropylene is not particularly limited, and examples thereof include carboxylic acid-modified polypropylene and the like. Examples of the carboxylic acid-modified polypropylene include, but are not limited to, maleic acid-modified polypropylene, maleic anhydride-modified polypropylene, anhydride-modified itaconic acid polypropylene, itaconic acid- modified polypropylene, acrylic acid- Polypropylene, fumaric acid-modified polypropylene, and citraconic acid-modified polypropylene. Among them, at least one acid-modified polypropylene selected from the group consisting of maleic acid-modified polypropylene, maleic anhydride-modified polypropylene and acrylic acid-modified polypropylene is preferably used as the acid-modified polypropylene.

The thermoplastic elastomer is not particularly limited, and examples thereof include olefin thermoplastic elastomer, styrene elastomer, hydrogenated styrene elastomer and the like.

Examples of the olefinic thermoplastic elastomer include, but are not limited to, ethylene -? - olefin copolymers and the like. Examples of the? -Olefin include propylene, 1-butene, 1-hexane and the like.

Examples of the styrene-based elastomer and the hydrogenated styrene-based elastomer include, but not limited to, styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, styrene- Butylene-styrene hydrogenated copolymer, styrene-ethylene-propylene-styrene hydrogenated copolymer, and the like.

Among them, as the thermoplastic elastomer, it is preferable to use one or two kinds of thermoplastic elastomers selected from the group consisting of ethylene-propylene rubber (EPR) and ethylene-propylene-butene rubber (EPBR). As the EPBR, for example, ethylene-propylene-1-butene rubber can be exemplified.

The melting point of the thermoplastic elastomer is preferably 80 캜 or lower. The use of a thermoplastic elastomer having a melting point of 80 占 폚 or less has an advantage in that the adhesiveness to the tab surface can be sufficiently secured at the time of heat sealing.

The MFR of the thermoplastic elastomer is preferably 5 g / 10 min or less. By using the thermoplastic elastomer having MFR of 5 g / 10 min or less, the thermoplastic elastomer among the acid-modified polypropylene (or the first resin component) in the base resin layer 2 is independent of the size of about 0.3 탆 to about 15 탆 So that a spherical dispersed phase is formed. Thus, there is an advantage that a sufficient yarn strength can be ensured even in an emergency resin composition.

The "acid-unmodified polypropylene" is not particularly limited, but one or two resins selected from the group consisting of homopolypropylene and random polypropylene (ethylene-propylene random copolymer) are used desirable. The propylene content in the ethylene-propylene random copolymer is preferably in the range of 85 mass% to 99 mass%.

The content of the acid-modified polypropylene in the first resin component (the first resin component composed of the acid-modified polypropylene and the acid-unmodified polypropylene) is preferably set in the range of 1% by mass to 99% by mass . Among them, the content of the acid-modified polypropylene in the first resin component is more preferably set in the range of 1% by mass to 50% by mass, and in this case, the cost can be reduced, which is economical.

In the present invention, the thickness of the base resin layer 2 is preferably set to 20 to 70 mu m. The thickness of the outer resin layer 3 is preferably set to 15 to 40 mu m. Further, it is preferable that the thickness of the inner resin layer 4 is set to 15 탆 to 40 탆.

The thickness of the tap-sealing insulating film 1 of the present invention is preferably set to be 50 mu m to 150 mu m.

An embodiment of an electrochemical device 20 constructed using the insulating film 1 for tap sealing according to the present invention is shown in Fig. The electrochemical device 20 includes an electrochemical device, electrode tabs 21 and 22, an insulating film 1 for tap sealing, and a sheath 23.

An example of the manufacturing sequence of the electrochemical device 20 will be described. First, as shown in Fig. 2, the casing (outer film) 23, 23 cut out into two rectangular pieces in a rectangular shape are bonded to each other by heat-welding the three surrounding sides 23a, 23b, Thereby forming bag-like objects.

As shown in Fig. 2, the tab-sealing insulating films 1 and 1 are fused in the state of being sandwiched between both surfaces of the positive electrode tab 21 at portions corresponding to the seal portions 23d, (1, 1) is fitted in a state in which the tab-sealing insulating film (1, 1) is sandwiched in a portion corresponding to the seal portion (23d) These tabs 21 and 22 are joined and fixed to the electrochemical device by welding. The positive electrode tab 21 is made of, for example, a metal conductor such as aluminum or titanium. The negative electrode tab 22 is made of, for example, a metal conductor such as copper, nickel, or nickel-plated copper. The electrochemical device is constituted by stacking a positive electrode and a negative electrode through an electrolyte portion. As the tab material (the material of the tabs 21 and 22), it is preferable to use a rolled hard foil or a plate. The tabs 21 and 22 may be subjected to an undercut treatment in order to sufficiently prevent the corrosion of the metal surfaces constituting the tabs 21 and 22 and the adhesion with the insulating film 1 for tap sealing. For example, in the case of a chromate treatment, an aqueous solution of any one of the following 1) to 3) is applied to the surface of the metal material subjected to the degreasing treatment and then dried.

1) An aqueous solution comprising a mixture of phosphoric acid, chromic acid and a fluoride metal salt

2) an aqueous solution comprising a mixture of phosphoric acid, chromic acid and fluoride nonmetal salts

3) An aqueous solution comprising at least one resin selected from the group consisting of an acrylic resin, a chitosan derivative resin and a phenol resin, and a mixture of phosphoric acid, chromic acid (or chromium (III) salt) and a fluoride metal salt.

Next, an electrochemical device to which the tabs 21 and 22 are connected is accommodated in the bag-shaped object. Subsequently, with the seal portions 23d and 23d of the bag-shaped object, the tabs 21 and 22 are fitted through the tab-sealing insulating films 1 and 1, and the whole area of the seal portions 23d and 23d (See Figs. 2 and 3). Thereby, an electrochemical device (battery or the like) 20 in which the electrochemical device is housed in an enclosure (outer film) 23, 23 is fabricated. In this electrochemical device 20, the tip end portion 21b of the positive electrode tab 21 and the tip end portion 22b of the negative electrode tab 22 are led to the outside of the casing member 23 (see FIG. 2).

Further, the electrochemical device 20 of the present invention is not particularly limited as it is obtained by the above-described production method.

Example

Next, a specific embodiment of the present invention will be described, but the present invention is not limited to these embodiments.

<Materials>

(Resin composition (A))

, 60 parts by mass of maleic anhydride-modified polypropylene resin (grafted maleic anhydride amount 0.2% by mass) and 40 parts by mass of ethylene-propylene rubber (EPR, "TAHMA P-0480" available from Mitsui Chemicals) By melt-kneading the resin composition at a resin temperature of 100 占 폚. The MFR of the resin composition (A) is 1.3 g / 10 min, and the melting point of the resin composition (A) is 168 deg.

(Resin composition (B))

85 parts by mass of maleic anhydride-modified polypropylene resin (grafted maleic anhydride content: 0.2% by mass) and 15 parts by mass of ethylene-propylene rubber (EPR) were melted and kneaded at a resin temperature of 230 ° C by a twin-screw extruder. The MFR of the resin composition (B) is 6 g / 10 min, and the melting point of the resin composition (B) is 168 deg.

(Resin composition (C))

, 70 parts by mass of maleic anhydride-modified polypropylene resin (grafted maleic anhydride content: 0.2% by mass) and 30 parts by mass of ethylene-propylene rubber (EPR) were melted and kneaded at a resin temperature of 230 ° C by a twin-screw extruder. The MFR of the resin composition (C) is 3.5 g / 10 min, and the melting point of the resin composition (C) is 168 deg.

(Resin composition (D))

, 10 parts by mass of a maleic anhydride-modified polypropylene resin (grafted maleic anhydride content: 0.3% by mass), 89 parts by mass of a homopolypropylene resin (MFR: 0.4 g / 10 minutes), and 1 part by mass of ethylene-propylene rubber (EPR) And melting and kneading at a resin temperature of 230 캜. The MFR of the resin composition (D) is 0.5 g / 10 min, and the melting point of the resin composition (D) is 165 캜.

(Resin composition (E))

, 15 parts by mass of a maleic anhydride-modified polypropylene resin (grafted maleic anhydride content: 0.3% by mass), 83 parts by mass of a homopolypropylene resin (MFR: 0.4 g / 10 minutes) and 2 parts by mass of ethylene-propylene rubber (EPR) And melting and kneading at a resin temperature of 230 캜. The MFR of the resin composition (E) is 0.5 g / 10 min, and the melting point of the resin composition (E) is 163 캜.

(Resin composition (F))

75 parts by mass of maleic anhydride-modified polypropylene resin (grafted maleic anhydride content: 0.2% by mass) and 25 parts by mass of ethylene-propylene rubber (EPR) were melted and kneaded at a resin temperature of 230 ° C by a twin-screw extruder. The MFR of the resin composition (F) is 3.2 g / 10 min, and the melting point of the resin composition (F) is 134 캜.

(Resin (G))

Maleic anhydride-modified polypropylene resin (grafted maleic anhydride amount: 0.2 mass%). The MFR of the resin (G) is 3.5 g / 10 min, and the melting point of the resin (G) is 134 캜.

(Resin (H))

Random polypropylene resin (ethylene-propylene random copolymer; propylene content: 4% by mass). The MFR of the resin (H) is 3 g / 10 min, and the melting point of the resin (H) is 140 캜.

The term "MFR" means MFR (melt flow rate) measured under conditions of a temperature of 230 ° C. and a load of 2.16 kg in accordance with JIS K7210-1999.

The "melting point" was measured using a DSC (differential scanning calorimeter) (model DSC-60A) manufactured by Shimadzu Corporation under the "method of measuring the transition temperature of plastic" according to JIS K7121-1987, (Melting point) determined by a DSC curve obtained by measuring the melting point (melting point).

<Example 1>

The resin composition (B) was extruded from an extruder to obtain an 80 m-thick tap-sealing insulating film.

<Practical Example 2>

The resin composition (C) was extruded from an extruder to obtain an 80 m-thick tap-sealing insulating film.

&Lt; Example 3 >

The resin composition (D) was extruded from an extruder to obtain an 80 m-thick tap-sealing insulating film.

<Example 4>

The resin composition (E) was extruded from an extruder to obtain an 80 m-thick tap-sealing insulating film.

<Comparative Example 1>

The resin composition (A) was extruded from an extruder to obtain an 80 m-thick tap-sealing insulating film.

[Table 1]

&Lt; Example 5 >

An outer resin layer 3 made of a resin composition (F) having a thickness of 30 占 퐉 is laminated on one surface of a 40 占 퐉 -thick base resin layer 2 made of the resin composition (B) (1) having a structure in which an inner resin layer (4) having a thickness of 30 mu m and made of a resin composition (F) is laminated on the other surface of the substrate It was obtained by inflation molding method.

&Lt; Example 6 >

An outer resin layer 3 made of a resin composition (F) and having a thickness of 30 占 퐉 is laminated on one surface of a 40 占 퐉 -thick base resin layer 2 made of the resin composition (C) (1) having a structure in which an inner resin layer (4) having a thickness of 30 mu m made of the resin composition (F) is laminated on the other surface of the laminate is subjected to coextrusion inflation molding .

&Lt; Example 7 >

An outer resin layer 3 made of a resin composition (F) having a thickness of 30 占 퐉 is laminated on one surface of a 40 占 퐉 -thick base resin layer 2 made of the resin composition (D) (1) having a structure in which an inner resin layer (4) having a thickness of 30 mu m made of the resin composition (F) is laminated on the other surface of the laminate is subjected to coextrusion inflation molding .

&Lt; Example 8 >

An outer resin layer 3 made of a resin composition (F) and having a thickness of 30 占 퐉 is laminated on one side of a base resin layer 2 having a thickness of 40 占 퐉 made of the resin composition (E) (1) having a structure in which an inner resin layer (4) having a thickness of 30 mu m made of the resin composition (F) is laminated on the other surface of the laminate is subjected to coextrusion inflation molding .

<Comparative Example 2>

An outer resin layer 3 made of a resin composition (F) having a thickness of 30 占 퐉 is laminated on one surface of a 40 占 퐉 -thick base resin layer 2 made of the resin composition (A) (1) having a structure in which an inner resin layer (4) having a thickness of 30 mu m made of the resin composition (F) is laminated on the other surface of the laminate is subjected to coextrusion inflation molding .

[Table 2]

&Lt; Example 9 &

An outer resin layer 3 made of resin G and having a thickness of 30 mu m is laminated on one surface of a base resin layer 2 having a thickness of 40 mu m made of the resin composition (C) And an inner resin layer 4 made of a resin G and having a thickness of 30 mu m laminated on the other surface was obtained by a coextrusion inflation molding method.

&Lt; Example 10 &

An outer resin layer 3 made of resin H and having a thickness of 30 占 퐉 is laminated on one surface of a 40 占 퐉 -thick base resin layer 2 made of the resin composition (B) And an inner resin layer 4 made of a resin G and having a thickness of 30 mu m laminated on the other surface was obtained by a coextrusion inflation molding method.

[Table 3]

Each tap-sealing insulating film obtained as described above was evaluated based on the following evaluation method. The results are shown in Tables 1 to 3.

&Lt; Evaluation method of sealing performance by actual strength measurement >

The surface of the inner resin layer of the obtained tap-sealing insulating film was overlaid on the surface of the tab lead material (tab), and the surface of the inner layer of the casing was overlaid on the surface of the outer resin layer of the insulating film, (Tap) / tap-sealing insulating film / jacket were actually joined to each other by heating with a heating furnace to obtain a seal joint. The exterior material was obtained by dry laminating a biaxially stretched polyamide film having a thickness of 25 占 퐉 on one side of an aluminum foil having a thickness of 40 占 퐉, (Unstretched) polypropylene film (inner layer). The tab lead material (tab) was plated with a nickel plating having a thickness of 0.3 mm, a width of 60 mm and a length of 50 mm on a copper foil with a thickness of 2 탆, and further with an aqueous solution containing chitosan resin, chromium fluoride and phosphoric acid .

Next, the bonded body was cut in the longitudinal direction to cut out a specimen having a width of 15 mm and a length of 150 mm. Next, in accordance with JIS Z0238-1998, the outer surface of the test piece and the insulating tape for tap sealing are checked together with a check portion on the upper side of the stroograph of Toyo Precision Machinery Co., Ltd., and the tab lead material is checked , And the peel strength was measured when the tape was peeled 180 degrees at a tensile speed of 10 mm / min. The peel strength was determined as the actual strength (N / 15 mm width) between the tab lead material and the tap sealing insulating film. (Seal-Strength) -D ((Seal-Strength)) where the ordinate is the actual strength (N / 15 mm width) and the abscissa is the elongation (displacement of breakage of the tap sealing insulation film; Distance) curve was recorded. From this SD curve, the sealing performance (sealing strength) of the insulating film for tap-sealing was evaluated based on the following criteria.

(Criteria)

?: The SD curve shows no decrease in the actual strength after the first yield point (yield point) and an actual strength of 50 (N / 15 mm width) or more after the first yield point The resultant was regarded as acceptable)

&Quot; DELTA &quot;: In the S-D curve, after the first yield point, a substantial decrease in the actual strength was observed. However, after the first yield point, the actual strength of 50 (N /

&Quot; X &quot;: In the S-D curve, a substantial drop in the actual strength is recognized after the first yield point, and the actual strength is less than 50 (N / 15 mm width) after the first yield point.

&Lt; Evaluation method of sealing performance by observation of separation interface >

The color of the peeling interface after the above 180-degree peeling test was visually examined, and the peeling position (peeling position) at which the peeling interface was peeled was observed by SEM (scanning electron microscope) The sealing performance (sealing strength) of the tab-sealing insulating film was evaluated based on the criteria. In the color of the peeling interface, the white part indicates that cohesion failure occurs in the layer, and the gray part indicates that cohesive failure occurs at the interface between the resin layer and the resin layer.

(Criteria)

The peeling position is the interface between the base resin layer and the outer resin layer or the interface between the base resin layer and the inner resin layer (cohesive failure in the vicinity of the resin layer) (This &quot; O &quot; evaluation was judged to be acceptable)

X: The color of the peeling interface is white on the whole, and the peeling position is not within the resin layers (the interface between the resin layers) but within the base resin layer (cohesive failure occurs inside the base resin layer).

As is apparent from Tables 1 to 3, the tap-sealing insulating films of Examples 1 to 10 of the present invention are excellent in sealing strength, and even when the internal pressure in an electrochemical device such as a battery is increased, A satisfactory sealed state through the insulating film can be sufficiently maintained.

On the other hand, in Comparative Example 1, since the content of the thermoplastic elastomer in the resin composition exceeds 30% by mass, the sealing strength is inferior to the sealing strength, and when the internal pressure in an electrochemical device such as a battery is increased, A satisfactory sealed state through the sealing insulating film can not be sufficiently maintained. In Comparative Example 2, the content of the thermoplastic elastomer in the base resin layer exceeds 30% by mass. Therefore, the sealing strength is inferior to the sealing strength, and when the internal pressure in an electrochemical device such as a battery is increased, A satisfactory sealed state through the sealing insulating film can not be sufficiently maintained.

The tap-sealing insulation film according to the present invention is suitably used as an insulation film for tap-sealing an electrochemical device such as a battery or a capacitor.

This application is a continuation of Japanese Patent Application No. 2014-43461, filed on March 6, 2014, which is incorporated herein by reference in its entirety.

The terms and explanations used here are used for explaining the embodiments of the present invention, and the present invention is not limited thereto. The present invention permits any design change, provided it is within the scope of the claims, without departing from the spirit thereof.

1: Insulation film for tap sealing
2: Base resin layer
3: outer resin layer
4: Inner resin layer
20: electrochemical device
21: positive electrode tab
22: Negative electrode tab
23: Outer material

Claims (11)

A base resin layer comprising a resin composition containing 70% by mass to 99% by mass of an acid-modified polypropylene and 1% by mass to 30% by mass of a thermoplastic elastomer,
Wherein the melting point of the resin composition is 155 占 폚 or higher and the MFR of the resin composition is 10 g / 10 minutes or less. A base resin layer composed of a resin composition comprising 70% by mass to 99% by mass of a first resin component comprising an acid-modified polypropylene and an acid-unmodified polypropylene, and 1% by mass to 30% by mass of a thermoplastic elastomer At least,
Wherein the melting point of the resin composition is 155 占 폚 or higher and the MFR of the resin composition is 10 g / 10 minutes or less. 3. The method according to claim 1 or 2,
Wherein the insulating film has a structure in which an outer resin layer is laminated on a surface facing the jacket in the base resin layer and an inner resin layer is laminated on a surface in a tab side of the base resin layer, Modified polypropylene and / or an acid-modified polypropylene, wherein the inner resin layer contains an acid-modified polypropylene. The method of claim 3,
Wherein the melting point of the outer resin layer is from 130 캜 to 140 캜, the melting point of the inner resin layer is from 130 캜 to 140 캜,
Wherein the melting point of the base resin layer is 25 占 폚 or more higher than the melting point of the outer resin layer and 25 占 폚 or more higher than the melting point of the inner resin layer. 5. The method of claim 4,
Wherein the melting point of the base resin layer is 25 占 폚 to 45 占 폚 higher than the melting point of the outer resin layer and 25 占 폚 to 45 占 폚 higher than the melting point of the inner resin layer. 3. The method according to claim 1 or 2,
Wherein the insulating film has a structure in which an outer resin layer is laminated on the side of the casing material in the base resin layer and an inner resin layer is laminated on the side of the tab resin in the base resin layer,
Wherein the outer resin layer comprises a resin composition having a melting point of less than 155 占 폚 containing 70% by mass to 99% by mass of an acid-modified polypropylene and 1% by mass to 30% by mass of a thermoplastic elastomer,
Characterized in that the inner resin layer is made of a resin composition having a melting point of less than 155 캜 and containing 70% by mass to 99% by mass of acid-modified polypropylene and 1% by mass to 30% by mass of thermoplastic elastomer Insulation film. 3. The method according to claim 1 or 2,
Wherein the insulating film has a structure in which an outer resin layer is laminated on the side of the casing material in the base resin layer and an inner resin layer is laminated on the side of the tab resin in the base resin layer,
Wherein the outer resin layer contains a first resin component comprising 70% by mass to 99% by mass of a first resin component comprising acid-modified polypropylene and an acid-unmodified polypropylene, and 1% by mass to 30% by mass of a thermoplastic elastomer Lt; RTI ID = 0.0 &gt; 155 C, &lt; / RTI &
Wherein the inner resin layer has a melting point comprising 70% by mass to 99% by mass of a first resin component composed of an acid-modified polypropylene and an acid-unmodified polypropylene, and 1% by mass to 30% by mass of a thermoplastic elastomer Lt; RTI ID = 0.0 &gt; 155 C. &Lt; / RTI &gt; 8. The method according to any one of claims 1 to 7,
Wherein the melting point of the thermoplastic elastomer is 80 占 폚 or less and the MFR of the thermoplastic elastomer is 5 g / 10 min or less. 9. The method according to any one of claims 1 to 8,
Wherein the thermoplastic elastomer is one or two kinds of resins selected from the group consisting of ethylene-propylene rubber and ethylene-propylene-butene rubber. An electrochemical device comprising the insulating film for tap sealing according to any one of claims 1 to 9. [0030]
An electrochemical device accommodated in the casing,
An inner end portion electrically connected to the electrochemical device, and an outer end portion provided on the outer side of the casing,
The seal portion of the casing is bonded to both surfaces of the tab in a state in which both surfaces of the tab are sandwiched by the seal portion of the casing through the tab-sealing insulating film according to any one of Claims 1 to 9 &Lt; / RTI &gt;

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