JP6511694B6 - battery - Google Patents

Description

  The present invention relates to a battery.

  In a battery, a cathode electrode, a separator, and an anode electrode may be laminated. For example, Patent Document 1 and Patent Document 2 disclose 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. The two separators are attached to each other via the thermoplastic resin.

  Furthermore, in Patent Document 3, there is a method of suppressing shrinkage of the first separators even when the temperature of the battery rises when the cathode electrode is positioned between the two first separators bonded to each other. Have been described. Specifically, in Patent Document 3, a second separator is provided between each first separator and the anode electrode. The second separator has a melting point lower than that of the first separator. Patent Document 3 describes that in this case, contraction of the first separator is suppressed even if the temperature of the battery rises.

Japanese Patent Application 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 novel separator having a high melting point between a cathode electrode and an anode electrode in a battery having a cathode electrode or an anode electrode between two separators bonded to each other.

According to the invention
A first electrode having a first surface and having a second surface which is a surface opposite to the first surface;
Covering the first surface, and the melting point is first of the first separator is a first temperature,
A second first separator which covers the second surface and is bonded to the first first separator, and the melting point is the first temperature;
Located opposite the first electrode through the first of the first separator, the melting point is rather higher than the first temperature, a second separator is a second temperature of 270 ° C. or higher 400 ° C. or less ,
Is formed by melting the part of the first of the first separator, a first adhesive layer bonding the first first separator and the second separator with each other,
The first electrode is different in polarity from the first electrode, has a third surface, and has a fourth surface which is a surface opposite to the third surface, and the third surface is through the second separator. A second electrode overlapping the first electrode so as to face the first surface of the first electrode;
Equipped with
A battery is provided , wherein the first first separator and the second separator do not overlap with the first adhesive layer but include portions that overlap each other and are not bonded to each other .

  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 point separator can be provided between the cathode electrode and the anode electrode in a novel structure.

It is a top view which shows the structure of the battery which concerns on 1st Embodiment. It is an AA 'cross section figure of FIG. It is a disassembled perspective view which shows the structure of the unit cell shown in FIG. (A) is a top view which shows the structure of the laminated body containing the cathode electrode shown in FIG. 3, (b) is an AA 'cross section figure 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 components are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

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 A-A 'of FIG. The battery includes a laminate 10, a cathode tab 20, an anode tab 30, a cover member 40, and an electrolyte 50.

  The cover member 40 includes covers 42 and 44 facing 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 sealing regions 46 located along the sides of the cover member 40. The covers 42 and 44 are bonded to each other in the sealing area 46. Thus, the area sandwiched by the covers 42 and 44 is sealed from the outside area. The covers 42 and 44 are formed using, for example, an aluminum film.

  The laminate 10 and the electrolytic solution 50 are located in the 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 one on another. The electrolytic solution 50 is a non-aqueous 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 lower fatty acid carboxylate.

  Examples of the above-mentioned 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); lactones 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; methyl formate Organic acid esters such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate and ethyl propionate; esters such as phosphoric acid triester; diglymes; triglymes; sulfolanes such as sulfolane and methyl sulfolane; 3 Oxazolidinones such as methyl-2-oxazolidinone; and sultones such as 1,3-propane sultone, 1,4-butane sultone, and naphtha sultone. The above-mentioned organic solvent may contain only one of these, or may contain two or more of these.

  In the example shown in FIG. 1, the cathode tab 20 and the anode tab 30 project outward from the same short side of the cover member 40 in plan view. Furthermore, the cathode tab 20 and the anode tab 30 are opposite to each other along this side. Thereby, a short circuit between 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 through the cathode lead 200 and the 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 drawing, 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 stacked in this order. Specifically, as described later with reference to FIG. 4, the cathode electrode 110 is located between the two first separators 130 attached to each other. Furthermore, the second separator 140 is attached to the first separator 130 covering one surface of the cathode electrode 110. Furthermore, the second separator 140 is bonded to the first separator 130 covering 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. It will be stacked. In this case, when the cathode electrode 110 and the anode electrode 120 are removed from the laminate 10, the second separator 140, the first separator 130, the first separator 130, and the second separator 140 are repeatedly stacked 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 to this figure, the 1st separator 130 and the 2nd separator 140 all have the same planar shape. The cathode electrode 110 is included inside the first separator 130 and the second separator 140 in a plan view. A part of the cathode lead 200 protrudes outside the area 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 a plan view. A part of the anode lead 300 protrudes outside the region overlapping the first separator 130 and the second separator 140.

  In the example shown in the drawing, 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 deviated, the change in the area of the region where the cathode electrode 110 and the anode electrode 120 overlap with each other is prevented.

The cathode electrode 110 contains a cathode active material. Specifically, the cathode active material is, for example, a complex oxide of lithium and a transition metal, such as a lithium nickel complex oxide, a lithium cobalt complex oxide, a lithium manganese complex oxide, and a lithium-manganese-nickel complex 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 phosphorus oxide. The anode electrode 120 contains an anode active material. Specifically, the anode active material is, for example, artificial graphite, natural graphite, amorphous carbon, diamond-like carbon, fullerene, carbon nanotubes, carbon materials such as carbon nanohorns; lithium metal materials; alloys such as silicon and tin Base materials; oxide base materials such as Nb ₂ O ₅ and TiO ₂ ; or a composite of these. The cathode lead 200 and the anode lead 300 are formed using metal (for example, copper or aluminum).

  FIG. 4A is a plan view showing the configuration of a laminate including the cathode electrode 110 shown in FIG. FIG.4 (b) is an AA 'cross section figure of Fig.4 (a). FIG. 5 is an enlarged view of a region surrounded by a broken line α in FIG. 4 (b).

  As shown in FIG. 4B and FIG. 5, the first separator 130 and the second separator 140 adjacent to each other are bonded to each other via the adhesive layer 132. Furthermore, 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. In detail, the melting point of the first separator 130 is a first temperature. On the other hand, the second separator 140 has a second temperature whose melting point is higher than the first temperature. And as the details will be described 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 which is the first temperature or more and less than the second temperature. It is formed by pressing the second separator 140 against the first separator 130.

  In the example shown in FIG. 4B and FIG. 5, in the cathode electrode 110, both the first surface and the second surface facing each other in the thickness direction are covered by the second separator 140. Thus, the cathode electrode 110 faces 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. Therefore, the heat resistance between the cathode electrode 110 and the anode electrode 120 can be made high.

  The first temperature is, for example, a temperature of 120 ° C. or more and 250 ° C. or less. On the other hand, the second temperature is, for example, a temperature of 270 ° C. or more and 400 ° C. or less. Furthermore, the first separator 130 is formed using a porous resin, and is formed using, for example, polypropylene or polyethylene. On the other hand, the second separator 140 is formed using a porous resin, and is formed using, for example, polyamide or polyimide.

  In the example shown to Fig.4 (a), the planar shape of the 1st separator 130 and the 2nd separator 140 is a rectangle which has a long side and a short side. In the example shown in the 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 where the cathode lead 200 protrudes. In the example shown to this figure (a), in planar view, the some contact bonding layer 132 is arrange | positioned in 1 row along each edge.

  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 four sides of the 1st separator 130 and the 2nd separator 140. As shown in FIG. And in the example shown to this figure (a), the some contact bonding layer 132 is arrange | positioned in 1 row along each edge of the 1st separator 130 and the 2nd separator 140. As shown in FIG. In the example shown in FIG. 6A, the adhesive layer 132 is not formed in a region overlapping the cathode lead 200 in a 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 on 2 sides of the 1st separator 130 and the 2nd separator 140. As shown in FIG. Specifically, in the example shown in FIG. 6A, the adhesive layer 132 is disposed on the short side opposite to the short side where the cathode lead 200 protrudes, and is disposed on one of the remaining two sides. It is done. 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 of the 1st separator 130 and the 2nd separator 140. As shown in FIG. Furthermore, in the example shown to this figure (a), the contact bonding layer 132 continuously formed along each edge is mutually connected. Furthermore, in the example shown in FIG. 6A, one end of the adhesive layer 132 formed along the long side reaches the short side where the cathode lead 200 protrudes.

  FIG. 9 is a view showing a fourth modification of FIG. In the example shown in FIG. 6B, in the first separator 130, a first portion covering one surface of the cathode electrode 110 and a second portion covering the other surface of the cathode electrode 110 are integrally formed. The first separator 130 is folded back from the first portion to the second portion. Similarly, the second separator 140 may have a first portion opposite to the cathode electrode 110 through the first portion of the first separator 130 and an opposite portion of the cathode electrode 110 through the second portion of the first separator 130. The part located on the side is formed integrally. The second separator 140 is folded back from the first portion to the second portion.

  FIG. 10 is a view showing an example of a method of 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. Subsequently, as shown to this figure (b), the press 600 is pressed on the 2nd separator 140 located in the top layer of this laminated body. The tip of the press 600 is heated to a third temperature which is equal to or higher 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 this laminate. As a result, in the first separator 130, the portion on which the second separator 140 is pressed melts. Thus, the adhesive layer 132 (FIG. 4) is formed between the first separator 130 and the second separator 140 adjacent to each other and between the two first separators 130 sandwiching 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 more and 300 ° C. or less.

  In the example shown in the 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) located 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 substantially simultaneously. And these adhesion layers 132 will mutually overlap in planar view.

  As described above, according to the present embodiment, the first separator 130 having a low melting point and the second separator 140 having a high melting point are attached to each other. 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. Then, one surface of the cathode electrode 110 is covered by 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.

Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than the above can also be adopted.
Hereinafter, an example of a reference form is added.
1. A first electrode having a first surface and having a second surface which is a surface opposite to the first surface;
Two first separators, one covering the first surface, the other covering the second surface, the one and the other being bonded to each other, and the melting point being the first temperature;
A second separator located on the opposite side of the first electrode via the one, and having a second temperature, the melting point being higher than the first temperature;
A first adhesive layer formed by melting the one part, and bonding the one and the second separator to each other;
Battery.
2. 1. In the battery described in
A third separator located opposite to the first electrode via the other, and having a melting point of the second temperature;
A second adhesive layer formed by melting the other part, and bonding the other and the third separator to each other;
Battery.
3. 2. In the battery described in
The two first separators are formed using different separators,
The battery in which the said 2nd separator and the said 3rd separator are formed using a mutually different separator.
4. 2. In the battery described in
The two first separators are
It is formed as one,
Folded back from the one side to the other side,
The second separator and the third separator are
It is formed as one,
The battery folded over from one side to the other side of the second separator and the third separator.
5. 2. ~ 4. In the battery described in any one of
A battery in which the first adhesive layer and the second adhesive layer overlap each other in plan view.

DESCRIPTION OF SYMBOLS 10 laminated body 20 cathode tab 30 anode tab 40 cover member 42 cover 46 cover 46 sealing area 50 electrolyte solution 100 unit cell 110 cathode electrode 130 anode electrode 130 first separator 132 adhesive layer 140 second separator 200 cathode lead 300 anode lead 600 press

Claims (5)

A first electrode having a first surface and having a second surface which is a surface opposite to the first surface;
Covering the first surface, and the melting point is first of the first separator is a first temperature,
A second first separator which covers the second surface and is bonded to the first first separator, and the melting point is the first temperature;
Located opposite the first electrode through the first of the first separator, the melting point is rather higher than the first temperature, a second separator is a second temperature of 270 ° C. or higher 400 ° C. or less ,
Is formed by melting the part of the first of the first separator, a first adhesive layer bonding the first first separator and the second separator with each other,
The first electrode is different in polarity from the first electrode, has a third surface, and has a fourth surface which is a surface opposite to the third surface, and the third surface is through the second separator. A second electrode overlapping the first electrode so as to face the first surface of the first electrode;
Equipped with
The battery according to claim 1, wherein the first first separator and the second separator do not overlap with the first adhesive layer but include portions that overlap each other and are not bonded to each other . In the battery according to claim 1,
A third separator located on the opposite side of the first electrode via the second first separator , and having a melting point of the second temperature;
Is formed by melting a portion of the second of the first separator, and a second adhesive layer for bonding the second of the first separator and the third separator to each other,
Equipped with
The battery according to claim 1, wherein the second first separator and the third separator do not overlap with the second adhesive layer but include portions that overlap each other and are not bonded to each other . In the battery according to claim 2,
The first first separator and the second first separator are formed using different separators,
The battery in which the said 2nd separator and the said 3rd separator are formed using a mutually different separator. In the battery according to claim 2,
The first first separator and the second first separator are
It is formed as one,
The first and the first folded toward the separator and the hand or al the other side of the second of the first separator,
The second separator and the third separator are
It is formed as one,
The battery folded over from one side to the other side of the second separator and the third separator. In the battery according to any one of claims 2 to 4,
A battery in which the first adhesive layer and the second adhesive layer overlap each other in plan view.

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