JP2009187772A - Manufacturing method of electrode foil for nonaqueous electrolyte battery, and manufacturing method of electrode plate for nonaqueous electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of electrode foil for a nonaqueous electrolyte battery in which generation of a film consisting of fluoride and oxide on the surface of the metal foil is prevented and resistance generated between the active material layer and the metal foil is made small. <P>SOLUTION: This is the manufacturing method of electrode foil 20 for nonaqueous electrolyte battery having the metal foil and a coated layer 40 which is arranged on the foil surfaces 31, 32 of the metal foil and in which carbon particle parts 42 having graphite structure are dispersed in scattered spot-like on an amorphous carbon film 41, and comprises a coated layer forming process in which, using a target 110 consisting of porous carbon in which a great number of pores BH are dispersed on the surface and inside, amorphous carbon film is grown on the foil surface of the metal foil using a sputter method and the carbon particle parts are dispersedly arranged to form the coating layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a non-aqueous electrolyte battery electrode foil and a method for producing a non-aqueous electrolyte battery electrode body using the electrode foil.

  In recent years, with the spread of portable electronic devices such as mobile phones, notebook computers, and video camcorders and vehicles such as hybrid electric vehicles, the demand for batteries used for these driving power sources is increasing. An example of such a battery is a non-aqueous electrolyte battery having a high energy density. This non-aqueous electrolyte battery has a structure in which a power generation element in which a positive electrode and a negative electrode are laminated or wound through a separator impregnated with a non-aqueous electrolyte is contained in a battery case.

By the way, at the time of manufacture or charge / discharge of this nonaqueous electrolyte battery, the electrode foil (for example, aluminum foil or copper foil) constituting the positive electrode or the negative electrode reacts with the nonaqueous electrolyte solution, for example, fluoride. A film of oxide or the like is formed on the surface of the electrode foil. Then, the resistance between the electrode foil and the active material layer disposed on the surface increases, so that the internal resistance of the nonaqueous electrolyte battery may increase.
Thus, for example, Patent Document 1 proposes a non-aqueous electrolyte battery current collector (metal foil) in which a composition layer containing a conductive additive and an active material is disposed on the surface of a current collector (metal foil). .

JP 2006-286344 A

  However, in the non-aqueous electrolyte battery current collector (metal foil) of Patent Document 1, the resistance between the metal foil and the composition layer can be reduced by the conductive assistant, but this conductive assistant is an active material. Moreover, since it is arrange | positioned on metal foil, it cannot prevent that nonaqueous electrolyte solution contacts metal foil. For this reason, there exists a possibility that films | membranes, such as a fluoride and an oxide, may generate | occur | produce on metal foil with a non-aqueous electrolyte. Since the film | membrane produced | generated in this way becomes a resistor in conduction | electrical_connection between metal foil and a composition layer, there exists a possibility of reducing the electroconductivity between both.

  The present invention has been made in view of the current situation, and prevents the formation of a film made of fluoride or oxide on the surface of the metal foil, and reduces the resistance generated between the active material layer and the metal foil. It aims at providing the manufacturing method of the electrode foil for nonaqueous electrolyte batteries. Moreover, it aims at providing the manufacturing method of the electrode body for nonaqueous electrolyte batteries using such an electrode foil.

  And the solution means is a metal foil and a coating layer disposed on the foil surface of the metal foil, in which the particulate carbon particle parts having a graphite structure are dispersed in a dispersed manner in an amorphous carbon film, and The electrode foil for a non-aqueous electrolyte battery comprising a plurality of pores dispersed on the surface and inside, and using a target made of porous carbon having a graphite structure, by the sputtering method, Production of an electrode foil for a nonaqueous electrolyte battery comprising a coating layer forming step of growing the amorphous carbon film on the foil surface of the metal foil and dispersing and arranging the carbon particle portions to form the coating layer Is the method.

  The method for producing an electrode foil for a nonaqueous electrolyte battery of the present invention includes a coating layer forming step of forming a coating layer by sputtering using a target made of porous carbon. When a voltage is applied to the target porous carbon, the electric field formed around the porous carbon concentrates around the vacancies opening on the surface, and, for example, ions such as argon ions are formed around the carbon around the vacancies. Easy to collide with. Then, in addition to releasing carbon atoms from the target, many droplets of carbon particles that maintain the crystalline state of graphite are released, and these deposit on the foil surface of the metal foil. Thus, on the metal foil, in addition to the amorphous carbon film in which carbon atoms are deposited and grown, a coating layer in which the carbon particle portions are dispersed and arranged in the form of scattered dots is formed.

  Among these coating layers, the amorphous carbon film functions as a corrosion-resistant film that suppresses oxidation or corrosion of the foil surface of the metal foil. Further, since the carbon particle portion is made of carbon having a graphite structure, it has higher conductivity than the amorphous carbon film, and the conductivity of the coating layer can be improved. Thus, the formation of a film of oxide or fluoride on the surface of the metal foil is prevented, and an increase in resistance generated between the active material layer and the metal foil is suppressed, and conversely, the conduction between the two is carbon particles. An electrode foil for a nonaqueous electrolyte battery that is more favorable for the part can be produced.

The amorphous carbon film refers to an amorphous carbon film in which carbon bonded through sp2 hybrid orbitals and carbon bonded through sp3 hybrid orbitals are mixed.
Examples of the sputtering method include a bipolar sputtering method, a tripolar (or quadrupolar) sputtering method, a magnetron sputtering method, a high frequency sputtering method, and a bias sputtering method.

  In addition, as porous carbon, for example, carbon particles having a particle diameter of about 1 to 5 mm and styrene particles are mixed at a volume ratio of carbon particles: styrene particles = 2: 1 and then fired to obtain a crystal structure of a graphite structure. The part which the part which it has disperse | distributed and formed is mentioned.

  Furthermore, in the method for producing an electrode foil for a non-aqueous electrolyte battery described above, the carbon particle part is a graphite particle part made of graphite, and in the coating layer forming step, the porous carbon is made of porous graphite made of graphite. A method for producing a non-aqueous electrolyte battery electrode foil is preferred.

  In the method for producing an electrode foil for a non-aqueous electrolyte battery according to the present invention, porous graphite made of graphite is used as porous carbon. Therefore, a large number of graphite particle droplets released from porous graphite are deposited on the metal foil. A coating layer in which the graphite particle portions are dispersed in the form of scattered dots is formed. Among the above-described carbon particle parts, the graphite particle part made of graphite has good conductivity, and therefore can reliably improve the conductivity of the coating layer.

  As porous graphite, for example, carbon particles having a particle diameter of about 1 to 5 mm and styrene particles are mixed at a volume ratio of carbon particles: styrene particles = 2: 1, and then fired at a firing temperature of 2000 to 2500 ° C. And graphite containing a large number of pores.

  Further, another solution is a metal foil and a coating layer disposed on the foil surface of the metal foil, in which particulate carbon particle parts having a graphite structure are dispersed in a dispersed manner in an amorphous carbon film. A non-aqueous electrolyte battery electrode foil, and an active material layer comprising an active material and supported on the coating layer, and a method for producing a non-aqueous electrolyte battery electrode body, the surface and The amorphous carbon film is grown on the foil surface of the metal foil by sputtering using a target made of porous carbon having a graphite structure while containing a large number of pores therein, and the carbon A nonaqueous electrolyte comprising: a coating layer forming step of dispersing and arranging the particle parts to form the coating layer; and a supporting step of supporting the active material layer on the coating layer It is a manufacturing method of the pond electrode body.

  The method for producing an electrode body for a nonaqueous electrolyte battery according to the present invention includes a coating layer forming step and a supporting step. Of these, in the coating layer formation process, in addition to the amorphous carbon film on which carbon atoms are deposited and grown, a coating layer in which carbon particle portions having a graphite structure are dispersed and arranged on the metal foil is formed. To do. For this reason, resistance generated between the electrode foil and the active material layer supported in the supporting step is low, and conduction is improved. Therefore, a nonaqueous electrolyte battery having a low internal resistance can be produced by using this electrode body for a nonaqueous electrolyte battery.

  Furthermore, in the above-described method for producing an electrode body for a water electrolyte battery, the carbon particle portion is a graphite particle portion made of graphite, and in the coating layer forming step, porous graphite made of graphite is added to the porous carbon. A method for producing an electrode body for a water electrolyte battery to be used is preferable.

  In the method for producing an electrode body for a water electrolyte battery according to the present invention, porous graphite made of graphite is used as porous carbon. Therefore, a large number of graphite particle droplets released from porous graphite are deposited on the metal foil. A coating layer in which the particle parts are dispersed in the form of scattered dots is formed. Among the above-described carbon particle parts, the graphite particle part made of graphite has good conductivity, and therefore can reliably improve the conductivity of the coating layer.

(Embodiment)
Next, embodiments of the present invention will be described with reference to the drawings.
First, the positive electrode plate 10 according to the present embodiment will be described. FIG. 1 is a perspective view of the positive electrode plate 10, and FIG. 2 is a partially enlarged sectional view of the positive electrode plate 10 (A portion in FIG. 1).
The positive electrode plate 10 according to the present embodiment is used for a lithium ion secondary battery (not shown) having a non-aqueous electrolyte.

  As shown in FIG. 1, the positive electrode plate 10 has a long strip shape extending in the longitudinal direction DA, and the first positive electrode active material layer 51 is formed on both surfaces of the positive electrode foil 20 when viewed in the laminating direction DL. And the 2nd positive electrode active material layer 52 is laminated | stacked and arrange | positioned. Specifically, the first positive electrode active material layer 51 and the second positive electrode active material layer 52 are disposed on the first electrode foil main surface 21 and the second electrode foil main surface 22 of the positive electrode foil 20.

Among these, the first positive electrode active material layer 51 and the second positive electrode active material layer 52 are both a positive electrode active material X made of LiNiO ₂ , acetylene black (AB, not shown), polytetrafluoroethylene (PTFE, not shown). And carboxymethylcellulose (CMC, not shown). The weight ratio in the positive electrode active material layers 51 and 52 was set to positive electrode active material X: AB: PTFE: CMC = 100: 10: 3: 1.

  Further, as shown in FIG. 3, the positive electrode foil 20 is in the form of a long strip extending in the longitudinal direction DA, and on the both sides of the foil body 30 made of aluminum as viewed in the thickness direction (stacking direction DL), A covering layer 40 that covers the foil body 30 is laminated. Specifically, the coating layer 40 is disposed on the first foil surface 31 and the second foil surface 32 of the foil body 30, respectively.

  Of these, the coating layer 40 is composed of an amorphous carbon film 41 covering the foil surfaces 31 and 32 and a particulate graphite particle portion 42 made of graphite dispersed in a scattered manner in the amorphous carbon film 41 (FIG. 4). Among these, the amorphous carbon film 41 functions as a corrosion-resistant film that suppresses oxidation and corrosion of the foil surfaces 31 and 32 of the foil body 30. That is, even if this positive electrode foil 20 is in contact with the electrolyte used in, for example, a lithium ion secondary battery, the amorphous carbon film 41 covers the foil surfaces 31 and 32 of the foil main body 30. It is possible to prevent the formation of a film of oxide or fluoride.

  However, the amorphous carbon film 41 is an amorphous carbon film, and for example, is often less conductive than allotrope graphite. Therefore, in the present embodiment, a large number of graphite particle portions 42 made of graphite are dispersed in the amorphous carbon film 41 to reliably improve the conductivity of the coating layer 40. That is, the electrical conductivity between the foil body 30 and the positive electrode active material layers 51 and 52 through the coating layer 40 is increased.

As shown in FIG. 2, the positive electrode plate 10 of the present embodiment includes the above-described coating layer 40 between the first positive electrode active material layer 51 and the first electrode foil main surface 21 and the second positive electrode active material layer. 52 and the second electrode foil main surface 22. Therefore, the resistance generated between the positive electrode foil 20 and the positive electrode active material layers 51 and 52 is low.
Thus, if the positive electrode plate 10 is used for a lithium ion secondary battery, the secondary battery can be a secondary battery having a low internal resistance.

Next, a method for manufacturing the positive electrode plate 10 according to the present embodiment will be described with reference to the drawings.
First, in FIG. 5A, a schematic diagram of a bipolar sputtering apparatus 100 responsible for the coating layer forming step of the positive electrode foil 20 in the method for manufacturing the positive electrode plate 10 is shown. The bipolar sputtering apparatus 100 includes an unwinding portion 101, a winding portion 102, a target 110, an anode terminal 131, a cathode terminal 132, a power supply device 150, a plurality of auxiliary rollers 140, A conduction auxiliary roller 140N is provided.

Among these, the vacuum container 120 can exhaust the inside of a container to a vacuum with the vacuum exhaust pump which is not illustrated. Thereafter, the vacuum container 120 is filled with a small amount of argon gas.
The foil body 30 is unwound from the unwinding unit 101 in the vacuum device 120, moved in the longitudinal direction DA by the plurality of auxiliary rollers 140 and the conduction auxiliary roller 140 </ b> N, and is wound by the winding unit 102. Among these, the conduction auxiliary roller 140N is made of metal and can be electrically connected to the foil body 30 (see FIG. 5). Since the positive electrode terminal 131 of the power supply device 150 is electrically connected to the conduction assisting roller 140N, when a voltage is applied using the power supply device 150, the entire foil body 30 becomes a positive potential.

The target 110 is made of porous graphite containing a large number of holes BH dispersed on the surface and inside. This porous graphite was obtained by mixing carbon particles having a particle diameter of about 1 to 5 mm and styrene particles at a volume ratio of carbon particles: styrene particles = 2: 1, and then firing at a firing temperature of 2000 to 2500 ° C. Is.
When such porous graphite is used for the target 110 and connected to the cathode terminal 132 and a voltage is applied by the power supply device 150, the electric field concentrates at the periphery of the hole BH opening on the surface of the target 110, and argon ions Tends to collide with the graphite around the pores BH, and in addition to the carbon atoms CA, many droplets of graphite particles CD that maintain the crystalline state of graphite are emitted from the target 110.

  In the bipolar sputtering apparatus 100 of this embodiment, a voltage is applied using the power supply apparatus 150. Then, the foil main body 30 is charged with a positive charge and the target 110 is charged with a negative charge. On the first foil surface 31 (or the second foil surface 32) of the foil main body 30, the above-described carbon atoms CA and droplets CD are described. Are deposited to form the coating layer 40. In this coating layer 40, the droplet CD becomes the graphite particle part 42 as it is.

  After the coating layer 40 is formed on the first foil surface 31 (or the second foil surface 32) of the foil body 30, the coating layer 40 is similarly formed on the second foil surface 32 of the foil body 30. Thus, the positive electrode foil 20 in which the covering layer 40 is laminated on the both foil surfaces 31 and 32 of the foil body 30 is produced.

Next, a supporting process using the coating apparatus 200 in the method for manufacturing the positive electrode plate 10 will be described.
As shown in FIG. 6, the coating apparatus 200 includes an unwinding unit 201, a die 210, a drying furnace 220, a winding unit 202, and a plurality of auxiliary rollers 240.
Among them, the die 210 includes a metal paste holding unit 211 that holds the active material paste AP therein, and the active material paste AP held in the paste holding unit 211 as a first electrode foil main layer of the positive electrode foil 20. It has a discharge port 212 for continuously discharging the active material paste AP toward the surface 21 or the second electrode foil main surface 22.
The discharge port 212 is slit-shaped, and the active material paste AP is strip-shaped on the foil main surface (the first electrode foil main surface 21 or the second electrode foil main surface 22) of the positive electrode foil 20 moving in the longitudinal direction DA. It opens in parallel to the width direction (depth direction in FIG. 6) of the positive electrode foil 20 so as to be discharged.

The active material paste AP held by the die 210 includes, in addition to the positive electrode active material X made of LiNiO ₂ , acetylene black (AB, not shown), polytetrafluoroethylene (PTFE, not shown), and carboxymethyl cellulose (CMC, shown). Is a fluid obtained by dispersing and kneading in ion exchange water AQ. Further, as described above, the weight ratio of the positive electrode active materials X, AB, PTFE and CMC contained in the active material paste AP is the positive electrode active material X: AB: PTFE: CMC = 100: 10: 3: 1. .

In the drying furnace 220, hot air is sent toward the active material paste AP applied to the positive electrode foil 20. Thus, the active material paste AP applied to the positive electrode foil 20 is gradually dried while moving in the drying furnace 220, and when passing through the drying furnace 220, the active material paste AP is completely dried. That is, all the water (ion exchange water AQ) in the active material paste AP evaporates.
The strip-shaped positive electrode foil 20 is moved in the longitudinal direction DA by the plurality of auxiliary rollers 240.

  In this coating apparatus 200, first, the belt-like positive electrode foil 20 wound around the unwinding portion 201 is moved in the longitudinal direction DA, and the first electrode foil main surface 21 of the positive electrode foil 20 is activated by the die 210. The substance paste AP is applied. Thereafter, the active material paste AP is dried together with the positive electrode foil 20 in the drying furnace 220, and the single-side supported electrode foil 20K in which the uncompressed active material layer (not shown) is supported on the first electrode foil main surface 21 is wound. It winds up around the take-up section 202 once.

  Next, using this coating apparatus 200 again, the active material paste AP is applied also to the second electrode foil main surface 22 of the positive electrode foil 20 in the above-described single-side supported electrode foil 20K. Then, this active material paste AP is completely dried in a drying furnace 220. Thus, the positive electrode plate 10B before pressing, in which the uncompressed positive electrode active material layer (not shown) is laminated on both the electrode foil main surfaces 21 and 22 of the positive electrode foil 20, is manufactured.

Next, FIG. 7 shows a press cutting process using the press device 300 in the supporting process of the method for manufacturing the positive electrode plate 10.
The press device 300 includes an unwinding unit 301, a press roller 310, a winding unit 302, a cutting blade 330, and a plurality of auxiliary rollers 320. And in this press apparatus 300, the above-mentioned positive electrode plate 10 compressed in the thickness direction is obtained by passing the above-mentioned positive electrode plate 10B before pressing from the unwinding part 301 between the two press rollers 310. Can do. Thereafter, the center is cut by the cutting blade 330 and divided into two, and the positive electrode plate 10 is wound by the two winding portions 302. Thus, the positive electrode plate 10 was manufactured (see FIGS. 1 and 2).

In the positive electrode foil 20 and the positive electrode plate 10 described above, the amorphous carbon film 41 in the coating layer 40 is a corrosion-resistant film that suppresses oxidation and corrosion of the foil surfaces 31 and 32 of the foil body 30. Function. Moreover, since the graphite particle part 42 consists of graphite, it has high electroconductivity compared with the amorphous carbon film 41, and can improve the electroconductivity of the coating layer 40 reliably. Specifically, in the positive electrode foil 20, the conductivity between the foil body 30 and the positive electrode active material layers 51 and 52 through the coating layer 40 can be improved. Thus, by using the positive electrode foil 20, a film such as an oxide or fluoride is prevented from being formed on the foil surfaces 31 and 32 of the foil body 30, and the positive electrode active material layers 51 and 52 and the foil body 30 are separated from each other. The positive electrode plate 10 having a low resistance generated therebetween can be manufactured.
Moreover, the lithium ion secondary battery with low internal resistance can be manufactured by using the positive electrode plate 10 using this positive electrode foil 20.

In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, in the embodiment, the positive electrode foil 20 is supported on the positive electrode foil 20 to form the positive electrode plate 10, but the present invention may be applied to a negative electrode plate in which the negative electrode active material layer is supported on the electrode foil. In that case, as the negative electrode active material layer, for example, a negative electrode active material made of graphite, a binder, a conductive agent, etc. are mixed. What formed the coating layer is mentioned.
Moreover, although the positive electrode active material X in the positive electrode active material layer was LiNiO ₂ , for example, LiCoO ₂ , LiMn ₂ O ₄ , LiFeO ₂ , Li ₅ FeO ₄ , Li ₂ MnO ₃ , LiFePO ₄ , LiV ₂ O ₄ , A mixture thereof may also be used. Furthermore, although the material of the metal foil is aluminum, for example, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, antimony, or the like may be used.

In the coating layer forming step, a bipolar sputtering method using a bipolar sputtering apparatus is used as the sputtering method. However, for example, a tripolar (or quadrupolar) sputtering method, a magnetron sputtering method, a high frequency sputtering method, or a bias sputtering method may be used.
Furthermore, porous graphite made entirely of graphite was used as the target 110 in the coating layer forming step. However, even if the whole is not graphite, the target 110 is made of porous carbon containing a large number of pores dispersed on the surface and inside, and partly containing a portion having a crystal structure of graphite structure. In addition to the carbon film 41, a coating layer in which carbon particles having a graphite structure are dispersed may be formed instead of the graphite particle portion 42.

It is a perspective view of the positive electrode plate concerning an embodiment. It is a partial expanded end view (A section of Drawing 1) of a positive electrode board concerning an embodiment. It is a perspective view of the positive electrode foil concerning embodiment. It is a partial expanded end view (B section of Drawing 3) of positive electrode foil concerning an embodiment. It is explanatory drawing of the coating layer formation process of embodiment, (a) is a schematic diagram of a bipolar sputtering apparatus, (b) is the elements on larger scale of a target. It is explanatory drawing of a coating process among the support processes of embodiment. It is explanatory drawing of a press cutting process among the holding processes of embodiment.

Explanation of symbols

10 Positive electrode plate (electrode body for non-aqueous electrolyte battery)
20 Positive electrode foil (electrode foil for non-aqueous electrolyte battery)
30 Foil body (metal foil)
31 First foil surface (foil surface)
32 Second foil surface (foil surface)
40 Coating Layer 41 Amorphous Carbon Film 42 Graphite Particle Part 51 First Cathode Active Material Layer 52 Second Cathode Active Material Layer 110 Target BH Hole X Cathode Active Material (Active Material)

Claims (4)

Metal foil,
An electrode foil for a non-aqueous electrolyte battery, comprising: a coating layer disposed on a foil surface of the metal foil, and a particulate carbon particle portion having a graphite structure dispersed in an amorphous carbon film in a scattered manner A manufacturing method comprising:
The amorphous carbon film is grown on the surface of the metal foil by a sputtering method using a target made of porous carbon having a graphite structure and including a large number of pores dispersed on the surface and inside. The manufacturing method of the electrode foil for nonaqueous electrolyte batteries provided with the coating layer formation process which disperse | distributes and arrange | positions the said carbon particle part and forms the said coating layer. It is a manufacturing method of the electrode foil for nonaqueous electrolyte batteries according to claim 1,
The carbon particle part is a graphite particle part made of graphite,
In the coating layer forming step,
The manufacturing method of the electrode foil for nonaqueous electrolyte batteries which uses the porous graphite which consists of graphite for the said porous carbon. A non-aqueous electrolyte battery comprising: a metal foil; and a coating layer disposed on the surface of the metal foil, wherein the amorphous carbon film has particulate carbon particle portions having a graphite structure dispersed in a scattered manner. Electrode foil, and
A method for producing an electrode body for a non-aqueous electrolyte battery comprising an active material and an active material layer carried on the coating layer,
The amorphous carbon film is grown on the surface of the metal foil by a sputtering method using a target made of porous carbon having a graphite structure and including a large number of pores dispersed on the surface and inside. A coating layer forming step of dispersing and arranging the carbon particle parts to form the coating layer;
A method for producing an electrode body for a nonaqueous electrolyte battery, comprising: a supporting step for supporting the active material layer on the coating layer. It is a manufacturing method of the electrode object for nonaqueous electrolyte batteries according to claim 1,
The carbon particle part is a graphite particle part made of graphite,
In the coating layer forming step,
The manufacturing method of the electrode body for nonaqueous electrolyte batteries which uses the porous graphite which consists of graphite for the said porous carbon.

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