WO2016084411A1

WO2016084411A1 - Battery

Info

Publication number: WO2016084411A1
Application number: PCT/JP2015/065413
Authority: WO
Inventors: 暁宏茂出木
Original assignee: Ｎｅｃエナジーデバイス株式会社
Priority date: 2014-11-27
Filing date: 2015-05-28
Publication date: 2016-06-02
Also published as: JP2016103377A; JP6511694B6; JP6511694B2

Abstract

One of two first separators (130) covers a first surface of a cathode electrode (110), and the other covers a second surface of the cathode electrode (110). In addition, these two first separators (130) are bonded with each other. The first separators (130) have a melting point of a first temperature. Second separators (140) are positioned on opposite sides of the cathode electrode (110), with the first separators (130) being interposed therebetween, respectively. The second separators (140) have a melting point of a second temperature that is higher than the first temperature. Bonding layers (132) are formed by melting the first separators (130). The first separators (130) and the second separators (140) are bonded with each other by means of the bonding layers (132).

Description

battery

The present invention relates to a battery.

In a battery, a cathode electrode, a separator, and an anode electrode may be stacked. For example, Patent Literature 1 and Patent Literature 2 describe that a cathode electrode or an anode electrode is sandwiched between two separators. Specifically, in Patent Document 1, a thermoplastic resin is provided between two separators. In this case, the thermoplastic resin is melted by heating the separator. And two separators are mutually affixed through this thermoplastic resin.

Furthermore, in Patent Document 3, there is a method for suppressing the shrinkage of the first separator even when the temperature of the battery rises when the cathode electrode is positioned between the two first separators bonded to each other. Are listed. Specifically, in Patent Document 3, a second separator is provided between each first separator and the anode electrode. The second separator has a lower melting point than the first separator. Patent Document 3 describes that in this case, the first separator is prevented from shrinking even when the temperature of the battery rises.

Japanese Patent Laid-Open No. 61-80752 JP 2007-287724 A JP 2012-151036 A

As described above, in a battery, a cathode electrode or an anode electrode may be positioned between two separators bonded to each other. In order to increase the heat resistance between the cathode electrode and the anode electrode in a battery having such a structure, it is desirable to provide a high melting point separator between the cathode electrode and the anode electrode. The inventor examined a structure for providing a high melting point separator between the cathode electrode and the anode electrode.

An object of the present invention is to provide a separator having a high melting point between a cathode electrode and an anode electrode with a novel structure in a battery having a cathode electrode or an anode electrode between two separators bonded to each other.

According to the present invention,
A first electrode having a first surface and having a second surface opposite the first surface;
Two first separators, one covering the first surface, the other covering the second surface, the one and the other being bonded together, and the melting point being the first temperature;
A second separator located on the opposite side of the first electrode through the one and having a second temperature higher than the first temperature.
A first adhesive layer formed by melting a part of the one, and bonding the one and the second separator together;
A battery is provided.

According to the present invention, in a battery having a cathode electrode or an anode electrode between two separators bonded to each other, a high-melting separator can be provided between the cathode electrode and the anode electrode with a novel structure.

The above-described object and other objects, features, and advantages will be further clarified by a preferred embodiment described below and the following drawings attached thereto.

It is a top view which shows the structure of the battery which concerns on 1st Embodiment. FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. FIG. 3 is an exploded perspective view illustrating a configuration of a unit cell illustrated in FIG. 2. (A) is a plan view showing a configuration of a laminate including the cathode electrode shown in FIG. 3, and (b) is an AA ′ sectional view of (a). It is the figure which expanded the area | region enclosed with the broken line (alpha) of FIG.4 (b). It is a figure which shows the 1st modification of FIG. It is a figure which shows the 2nd modification of FIG. It is a figure which shows the 3rd modification of FIG. It is a figure which shows the 4th modification of FIG. It is a figure which shows an example of the manufacturing method of the laminated body shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

(First embodiment)
FIG. 1 is a plan view showing the configuration of the battery according to the first embodiment. FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG. The battery includes a laminate 10, a cathode tab 20, an anode tab 30, a cover member 40, and an electrolytic solution 50.

The cover member 40 includes covers 42 and 44 that face each other. The planar shape of the cover member 40 is a rectangle having a long side and a short side. The

covers

42 and 44 have a sealing region 46 positioned along each side of the cover member 40. The

covers

42 and 44 are bonded to each other in the sealing region 46. Thereby, the area | region pinched | interposed by the

covers

42 and 44 is sealed from an external area | region. The

covers

42 and 44 are formed using, for example, an aluminum film.

The laminate 10 and the electrolytic solution 50 are located in a space sealed by the cover member 40. The stacked body 10 includes a plurality of unit cells 100 (details will be described later with reference to FIG. 3) stacked on each other. The electrolytic solution 50 is a nonaqueous electrolytic solution. Specifically, the electrolytic solution 50 contains a lithium salt and an organic solvent.

Lithium salt described above, for _{_{_{example, LiClO 4, LiBF 6, LiPF}}} 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB (C 2 H ₅ ) ₄ , CF ₃ SO ₃ Li, CH ₃ SO ₃ Li, LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, or lithium of a lower fatty acid carboxylate.

Examples of the organic solvent include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), and vinylene carbonate (VC). Carbonates such as γ-butyrolactone and γ-valerolactone; ethers such as trimethoxymethane, 1,2-dimethoxyethane, diethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran; sulfoxides such as dimethyl sulfoxide Oxolanes such as 1,3-dioxolane and 4-methyl-1,3-dioxolane; nitrogen-containing solvents such as acetonitrile, nitromethane, formamide, and dimethylformamide; Organic acid esters such as ethyl acetate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate and ethyl propionate; esters such as phosphate triesters; diglymes; triglymes; sulfolanes such as sulfolane and methylsulfolane; Oxazolidinones such as 3-methyl-2-oxazolidinone; sultone such as 1,3-propane sultone, 1,4-butane sultone, and naphtha sultone. The organic solvent mentioned above may contain only 1 type of these, or may contain 2 or more types of these.

In the example shown in FIG. 1, the cathode tab 20 and the anode tab 30 protrude outward from the same short side of the cover member 40 in plan view. Further, the cathode tab 20 and the anode tab 30 are located on opposite sides along this side. Thereby, the short circuit of the cathode tab 20 and the anode tab 30 can be prevented. The cathode tab 20 and the anode tab 30 are electrically connected to the unit cell 100 via a cathode lead 200 and an anode lead 300 (described later with reference to FIG. 3), respectively.

FIG. 3 is an exploded perspective view showing the configuration of the unit cell 100 shown in FIG. As shown in the figure, the unit cell 100 includes a cathode electrode 110, an anode electrode 120, a first separator 130, a second separator 140, a cathode lead 200, and an anode lead 300. The cathode lead 200 is electrically connected to the cathode electrode 110. Similarly, the anode lead 300 is electrically connected to the anode electrode 120.

In the example shown in the figure, the anode electrode 120, the second separator 140, the first separator 130, the cathode electrode 110, the first separator 130, and the second separator 140 are laminated in this order. Specifically, as will be described later with reference to FIG. 4, the cathode electrode 110 is positioned between the two first separators 130 bonded to each other. Further, a second separator 140 is bonded to the first separator 130 that covers one surface of the cathode electrode 110. Further, a second separator 140 is bonded to the first separator 130 that covers the other surface of the cathode electrode 110.

In the example shown in this figure, in the laminate 10 shown in FIG. 2, the anode electrode 120, the second separator 140, the first separator 130, the cathode electrode 110, the first separator 130, and the second separator 140 are repeated in this order. Will be stacked. In this case, when the cathode electrode 110 and the anode electrode 120 are removed from the laminated body 10, the second separator 140, the first separator 130, the first separator 130, and the second separator 140 are repeatedly laminated in this order. In this case, uneven distribution of the first separator 130 and the second separator 140 can be prevented.

In the example shown in the figure, both the first separator 130 and the second separator 140 have the same planar shape. The cathode electrode 110 is included inside the first separator 130 and the second separator 140 in plan view. A part of the cathode lead 200 protrudes outside a region overlapping the first separator 130 and the second separator 140. Furthermore, the anode electrode 120 is included inside the first separator 130 and the second separator 140 in plan view. A part of the anode lead 300 protrudes outside a region overlapping with the first separator 130 and the second separator 140.

In the example shown in the figure, the cathode electrode 110 is included inside the anode electrode 120 in plan view. In this case, even if the arrangement of the cathode electrode 110 is slightly shifted, the area of the region where the cathode electrode 110 and the anode electrode 120 overlap each other is prevented from changing.

The cathode electrode 110 contains a cathode active material. Specifically, the cathode active material is a composite oxide of lithium and a transition metal such as lithium nickel composite oxide, lithium cobalt composite oxide, lithium manganese composite oxide, and lithium-manganese-nickel composite oxide. Transition metal sulfides such as TiS ₂ , FeS, and MoS ₂ ; transition metal oxides such as MnO, V ₂ O ₅ , V ₆ O ₁₃ , and TiO ₂ , or olivine-type lithium phosphate. The anode electrode 120 contains an anode active material. Specifically, the anode active material is, for example, carbon materials such as artificial graphite, natural graphite, amorphous carbon, diamond-like carbon, fullerene, carbon nanotube, and carbon nanohorn; lithium metal material; alloy such as silicon and tin A system material; an oxide system material such as Nb ₂ O ₅ and TiO ₂ ; or a composite thereof. The cathode lead 200 and the anode lead 300 are formed using a metal (for example, copper or aluminum).

FIG. 4A is a plan view showing a configuration of a laminate including the cathode electrode 110 shown in FIG. FIG. 4B is a cross-sectional view taken along the line AA ′ of FIG. FIG. 5 is an enlarged view of a region surrounded by a broken line α in FIG.

As shown in FIGS. 4B and 5, the first separator 130 and the second separator 140 that are adjacent to each other are bonded to each other via an adhesive layer 132. Further, the two first separators 130 sandwiching the cathode electrode 110 are also bonded to each other via the adhesive layer 132. The adhesive layer 132 is an adhesive layer formed by melting the first separator 130. Specifically, the melting point of the first separator 130 is the first temperature. On the other hand, the 2nd separator 140 is 2nd temperature whose melting | fusing point is higher than 1st temperature. As will be described in detail later, the adhesive layer 132 heats the second separator 140 from the opposite side of the first separator 130 via the second separator 140 to a third temperature that is equal to or higher than the first temperature and lower than the second temperature. It is formed by pressing the second separator 140 against the first separator 130.

In the example shown in FIGS. 4B and 5, the cathode electrode 110 is covered with the second separator 140 on both the first surface and the second surface facing each other in the thickness direction. Thereby, the cathode electrode 110 comes to face the anode electrode 120 (FIG. 3) with the second separator 140 interposed therebetween. As described above, the second separator 140 has a high melting point. For this reason, the heat resistance between the cathode electrode 110 and the anode electrode 120 can be made high.

1st temperature is the temperature of 120 to 250 degreeC, for example. On the other hand, 2nd temperature is temperature of 270 degreeC or more and 400 degrees C or less, for example. Furthermore, the 1st separator 130 is formed using the porous resin, for example, is formed using polypropylene or polyethylene. On the other hand, the 2nd separator 140 is formed using porous resin, for example, is formed using polyamide or polyimide.

In the example shown in FIG. 4A, the planar shape of the first separator 130 and the second separator 140 is a rectangle having a long side and a short side. In the example shown in this drawing, the cathode lead 200 protrudes from one side of the short side of the first separator 130 and the second separator 140. The adhesive layer 132 is disposed on three sides other than the side from which the cathode lead 200 protrudes. In the example shown in FIG. 5A, a plurality of adhesive layers 132 are arranged in a line along each side in a plan view.

FIG. 6 is a diagram showing a first modification of FIG. As shown to this figure (a), the contact bonding layer 132 may be arrange | positioned at 4 sides of the 1st separator 130 and the 2nd separator 140. FIG. And in the example shown to this figure (a), the some contact bonding layer 132 is arrange | positioned in a line along each edge | side of the 1st separator 130 and the 2nd separator 140. FIG. In the example shown in FIG. 4A, the adhesive layer 132 is not formed in a region overlapping the cathode lead 200 in plan view.

FIG. 7 is a diagram showing a second modification of FIG. As shown to this figure (a), the contact bonding layer 132 may be arrange | positioned only at 2 sides of the 1st separator 130 and the 2nd separator 140. FIG. Specifically, in the example shown in FIG. 5A, the adhesive layer 132 is disposed on the short side facing the short side from which the cathode lead 200 protrudes, and is disposed on one of the remaining two sides. Has been. A plurality of adhesive layers 132 are arranged in a line along each side.

FIG. 8 is a diagram showing a third modification of FIG. As shown to this figure (a), the contact bonding layer 132 may be continuously formed along each edge | side of the 1st separator 130 and the 2nd separator 140. FIG. Further, in the example shown in FIG. 5A, the adhesive layers 132 continuously formed along each side are connected to each other. Further, in the example shown in FIG. 5A, one end of the adhesive layer 132 formed along the long side reaches the short side from which the cathode lead 200 protrudes.

FIG. 9 is a diagram showing a fourth modification of FIG. In the example shown in FIG. 5B, the first separator 130 is formed integrally with a first portion that covers one surface of the cathode electrode 110 and a second portion that covers the other surface of the cathode electrode 110. The first separator 130 is folded back from the first part to the second part. Similarly, the second separator 140 is opposite to the cathode electrode 110 via the first part located on the opposite side of the cathode electrode 110 via the first part of the first separator 130 and the second part of the first separator 130. The part located in the side is formed integrally. The second separator 140 is folded from the first part to the second part.

FIG. 10 is a diagram showing an example of a method for manufacturing the laminate shown in FIG. First, as shown to this figure (a), the 2nd separator 140, the 1st separator 130, the cathode electrode 110, the 1st separator 130, and the 2nd separator 140 are laminated | stacked in this order. Next, as shown in FIG. 4B, the press 600 is pressed against the second separator 140 located in the uppermost layer of the laminate. The tip of the press 600 is heated to a third temperature that is not lower than the first temperature and lower than the second temperature. In this case, the second separator 140 in contact with the press 600 does not melt. On the other hand, the heat (third temperature) at the tip of the press 600 is transmitted to the back of the laminate. As a result, the portion of the first separator 130 where the second separator 140 is pressed melts. As a result, an adhesive layer 132 (FIG. 4) is formed between the first separator 130 and the second separator 140 that are adjacent to each other and between the two first separators 130 that sandwich the cathode electrode 110. When the first temperature is T1 [° C.], the third temperature is, for example, a temperature of (T1 + 5) ° C. or more and (T1 + 50) ° C. or less. More specifically, the third temperature is, for example, a temperature of 125 ° C. or higher and 300 ° C. or lower.

In the example shown in this figure, any adhesive layer 132 (for example, the adhesive layer 132 between the two first separators 130 sandwiching the cathode electrode 110 and the uppermost layer) positioned in a region overlapping the press 600 in plan view. The adhesive layer 132) between the second separator 140 and the first separator 130 covering one surface of the cathode electrode 110 is also formed almost simultaneously. These adhesive layers 132 overlap each other in plan view.

As mentioned above, according to this embodiment, the 1st separator 130 with low melting | fusing point and the 2nd separator 140 with high melting | fusing point are bonded together. In this case, the first separator 130 and the second separator 140 can be bonded to each other through the adhesive layer 132 formed by melting the first separator 130. One surface of the cathode electrode 110 is covered with the first separator 130 and the second separator 140. In this case, the anode electrode 120 located on the opposite side of the cathode electrode 110 via the second separator 140 faces the cathode electrode 110 via the second separator 140. Thereby, the heat resistance between the cathode electrode 110 and the anode electrode 120 can be made high.

As described above, the embodiments of the present invention have been described with reference to the drawings. However, these are exemplifications of the present invention, and various configurations other than the above can be adopted.

This application claims priority based on Japanese Patent Application No. 2014-240552 filed on November 27, 2014, the entire disclosure of which is incorporated herein.

Claims

A first electrode having a first surface and having a second surface opposite the first surface;
Two first separators, one covering the first surface, the other covering the second surface, the one and the other being bonded together, and the melting point being the first temperature;
A second separator located on the opposite side of the first electrode through the one and having a second temperature higher than the first temperature.
A first adhesive layer formed by melting a part of the one, and bonding the one and the second separator together;
A battery comprising:
The battery according to claim 1.
A third separator located on the opposite side of the first electrode through the other, the melting point being the second temperature;
A second adhesive layer formed by melting the other part of the other, and bonding the other and the third separator to each other;
A battery comprising:
The battery according to claim 2, wherein
The two first separators are formed using different separators,
The battery in which the second separator and the third separator are formed using different separators.
The battery according to claim 2, wherein
The two first separators are
Is formed as one piece,
Folded from the one to the other,
The second separator and the third separator are:
Is formed as one piece,
A battery folded from one of the second separator and the third separator to the other.
The battery according to any one of claims 2 to 4,
The battery in which the first adhesive layer and the second adhesive layer overlap each other in plan view.