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Packaging material for flat electrochemical cell

A packaging material and electrochemical technology, applied in packaging, wrapping paper, sealing materials, etc., can solve problems such as peeling, loss of battery function, and rupture of hot-melt adhesive resin layers

Active Publication Date: 2008-10-01
DAI NIPPON PRINTING CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] However, on the inner fold line of the peripheral sealing portion 10b, that is, the curved portion 10c, since the innermost layer of the outer package 10, that is, the hot-melt adhesive resin layer, has been melted once and crystallized during heat sealing, it is easy to bend. break
Moreover, when this fracture occurs, the electrolyte inside the outer package 10 will come into contact with the metal foil constituting the outer package 10, causing the metal foil to be energized, resulting in a significant drop in the output of the lithium ion battery and loss of battery function.
[0011] In addition, in the embossing process of forming the outer packaging body 10 by press molding, when a metal having excellent ductility such as aluminum is used on the metal foil constituting the outer packaging body 10, the innermost layer of the outer packaging body 10 The extension of the hot-melt adhesive resin layer cannot catch up with the extension of the aluminum, and the aluminum and the hot-melt adhesive resin layer may peel off, resulting in cracks on the hot-melt adhesive resin layer
Moreover, the battery packaging material shown in JP-A-2005-56729 does not completely solve the above-mentioned problems.
[0012] In addition, in addition to housing the lithium ion battery main body 2 in the outer packaging body 10, the same problem also occurs when a capacitor or an electric double layer capacitor is sealed.

Method used

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  • Packaging material for flat electrochemical cell
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  • Packaging material for flat electrochemical cell

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0086] The functions and effects of the present invention will be specifically described below using examples. In Example 1, when a propylene-based elastomer resin was mixed into a polypropylene layer constituting a hot-melt adhesive resin layer, the insulation of the sealed portion after heat sealing was evaluated.

[0087] In addition, the propylene-based elastomer resin used in this example was Notiio (registered trademark) PN-2070 manufactured by Mitsui Chemicals, Ltd. The propylene-based elastomer resin contained 71 mol% of constituent units derived from propylene, and contained constituent units derived from ethylene and constituent units derived from 1-butene as constituent units other than the constituent units derived from propylene. Moreover, its physical properties are that Shore A hardness (ASTM D2240) is 75; melting point is 138°C; density (ASTM D1505) is 867kg / m 3 ; glass transition temperature (Tg) is -29°C; haze is 7%; melt flow rate (MFR, ASTM D1238) is 7.0 g...

Embodiment 2

[0099] In Example 2, when a propylene-based elastomer resin was mixed with a polypropylene layer constituting a hot-melt adhesive resin layer, the limit formability thereof was evaluated.

[0100] First, the same thing as the packaging material for electrochemical cells of Comparative Example 1 obtained in Example 1 and Inventions 1 to 4 was prepared, and cut into a square of 80×120 mm. Then each sample is put into a forming metal mold (male type) corresponding to a forming metal mold (female type) with a diameter of 30 mm × 50 mm, and it is formed into a single-side embossed outer packaging body with a depth of 7.0 mm. The main body of the lithium-ion battery was enclosed in the final outer packaging body, and the electrolyte solution was put into it to seal it with a sealing width of 5 mm.

[0101]Next, put the positive terminal in the electrolyte, install the tip of the negative terminal so that it reaches the aluminum foil of the outer package, apply a voltage of 25V, 100V...

Embodiment 3

[0103] In Example 3, the sealing strength when a propylene-based elastomer resin was mixed with a polypropylene layer constituting a hot-melt adhesive resin layer was evaluated.

[0104] First, the same thing as the packing material for electrochemical cells of the comparative example obtained in Example 1 and Inventions 1-4 was prepared, and it cut into the sheet|seat of 60 mm (MD direction) x 60 mm (TD direction). Next, the sheet was folded in half in the TD direction, and the opposite sides were heat-sealed with a width of 7 mm to make a bag-shaped outer package with an opening in one direction. The surface pressure was 1.0 MPa and the sealing time was 3.0 The opening part is heat-sealed under the condition of seconds. At this time, samples were produced by changing the sealing temperature to conditions of 150°C, 170°C, 190°C, and 210°C.

[0105] Then, the heat-sealed portion on the above-mentioned opening portion of these samples is cut into a thin rectangular shape with ...

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Abstract

In a packaging material for electrochemical cell, a thermally adhesive resin layer is configured of a resin having a propylene based elastomer resin in a propylene based resin. This propylene based elastomer resin is a copolymer composed of a constitutional unit derived from propylene and a constitutional unit derived from an alpha-olefin having from 2 to 20 carbon atoms; when the total sum of the constitutional unit derived from propylene and the constitutional unit derived from an alpha-olefin is defined as 100% by mole, contains 50% by mole or more of the constitutional unit derived from propylene; and is satisfied with (a) a Shore A hardness (ASTM D2240) of from 65 to 90, (b) a melting point of from 130 DEG C to 170 DEG C, (c) a density (ASTM D1505) of from 860 to 875 kg / m3 and (d) a glass transition temperature as measured by DSC of from -25 DEG C to -35 DEG C.

Description

technical field [0001] The present invention relates to a packaging material for flat electrochemical cells having stable sealing properties, insulating properties, and formability. Background technique [0002] Lithium-ion batteries, also called lithium secondary batteries, have liquid, gel or polymer electrolytes, and contain positive and negative active materials made of polymers. In this lithium ion battery, lithium atoms (Li) in the positive electrode active material, that is, lithium transition metal oxides, become lithium ions (Li) during charging. + ) into the carbon layer of the negative electrode (intercalation), lithium ions (Li + ) from the carbon layer (deintercalation) and move to the positive electrode, and become the original lithium compound for charge and discharge reactions. Compared with nickel-cadmium batteries and nickel-hydrogen batteries, the battery has a higher output voltage and lower energy density. High, and there will be no apparent discharge ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/02B32B15/00B32B15/08B65D65/40B65D30/02B32B15/085H01G11/00H01G11/78
CPCY02E60/12Y02E60/13H01M50/124H01M50/119H01M50/121H01M50/133H01M50/134H01M50/183H01M50/581
Inventor 山下孝典奥下正隆秋田裕久保谷裕
Owner DAI NIPPON PRINTING CO LTD
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