JP2009199973A - Collector for nonaqueous secondary battery, electrode plate for nonaqueous secondary battery using the same, and nonaqueous secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a collector of an electrode plate for a nonaqueous secondary battery capable of securing strength of the collector necessary for manufacturing of the electrode plate and effectively supporting an electrode active material on a projected section at high sticking force since the projected section having a specific arrangement pattern is formed on the surface of the collector by making a processing roller having recessed sections pass through twice or more. <P>SOLUTION: In the collector for the nonaqueous secondary battery wherein at least a positive electrode active material or a negative electrode active material is held on a beltlike metal foil, a plurality of projected sections 2 are formed on at least one surface of the collector 1B made of metal foil, and fine projections 3 as surface treated sections for enhancing the sticking force with the electrode active material are formed on the surface of the tip of the projected section 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a non-aqueous secondary battery typified by a lithium ion battery, and more particularly to a current collector for a non-aqueous secondary battery, a non-aqueous secondary battery electrode plate using the same, and a non-aqueous secondary battery. It is.

In recent years, lithium secondary batteries, which are widely used as power sources for portable electronic devices, use a carbonaceous material capable of occluding and releasing lithium for the negative electrode and a composite oxidation of transition metal such as LiCoO ₂ and lithium for the positive electrode. As a result, a lithium secondary battery having a high potential and a high discharge capacity is realized. However, with the recent multi-functionalization of electronic devices and communication devices, it is desired to improve the characteristic deterioration accompanying the charge / discharge cycle of the lithium secondary battery. In general, as an electrode plate that is a power generation element of a lithium secondary battery, a positive electrode active material or a negative electrode active material, a binder as a binder, and a mixture paint in which a conductive material is kneaded and dispersed in a dispersion medium as required. Is applied to one or both sides of the current collector, dried and pressed.

  Here, as one of the causes of characteristic deterioration accompanying the charge / discharge cycle, there is a decrease in the binding force between the positive electrode active material mixture layer or the negative electrode active material mixture layer applied on the current collector and the current collector. This is because the binding force at the interface of the current collector is weakened due to expansion and contraction of the electrode plate accompanying charging and discharging, and the positive electrode active material mixture layer or the negative electrode active material mixture layer falls off.

  Therefore, as a means for increasing the binding force between the positive electrode active material mixture layer or the negative electrode active material mixture layer and the current collector, there is a method of increasing the contact area of the current collector interface, which is generally collected by electrolysis. The surface of the current collector is roughened by a method of etching the surface of the current collector or a method of depositing a constituent metal on the surface by electrodeposition. As another method for roughening the surface of the current collector as described above, for example, a method of forming fine irregularities on the surface by causing fine particles to collide with the surface of a rolled copper foil, which is a material to be processed, at high speed has been proposed. (For example, refer to Patent Document 1).

  In addition, a method has been proposed in which a metal foil is irradiated with laser light to form irregularities having a surface roughness of 0.5 to 10 μm with an average roughness of 10 points (see, for example, Patent Document 2).

  Although there are different purposes, various methods for forming irregularities on the surface of the current collector are known. For example, as shown in FIG. 7, the output density can be increased without reducing the thickness of the electrode active material mixture layer. For the purpose of obtaining an improved lithium secondary battery, a current collector 71 made of metal foil is sandwiched between a pair of guide rollers 72 and 73 so that the surface thereof is uneven, and the surface area per unit area is increased to increase the electrode activity. A method of increasing the contact area between the material mixture layer and the current collector has been proposed (see, for example, Patent Document 3).

  Further, for the purpose of obtaining a current collector for a lithium secondary battery excellent in the supportability and electrical conductivity of the electrode active material, one side of the metal foil as shown in FIGS. A method has been proposed in which the opposite surface protrudes when the surface is depressed and the irregularities regularly dispersed on the plane of the metal foil are formed (for example, see Patent Document 4).

  Furthermore, for the purpose of obtaining a lithium secondary battery with little variation in capacity, output, etc., excellent output characteristics, low cost and long life, embossing as shown in FIGS. There has been proposed a method of forming a portion and filling the concave portion with an electrode active material so that the surface of the convex portion is exposed or an electrode active material is attached (see, for example, Patent Document 5).

On the other hand, as another method for producing an electrode plate that is a power generation element of a lithium secondary battery, a method of forming a thin film of an electrode active material on a current collector by an electrolytic plating method, a vacuum deposition method, or the like is known. . Also in this method, it is important to obtain a battery having a stable binding force between the current collector and the electrode active material. For example, the electrode for a lithium secondary battery having a large discharge capacity and excellent charge / discharge cycle characteristics. For the purpose of obtaining a plate, a value of (surface roughness Ra of electrode active material thin film) − (surface roughness Ra of current collector) is 0.1 μm or less on a current collector made of a metal that does not alloy with lithium. Has been proposed (for example, see Patent Document 6).
JP 2002-79466 A JP 2003-258182 A JP-A-8-195202 Japanese Patent Laid-Open No. 2002-270186 JP-A-2005-32642 JP 2002-279972 A

  However, the larger the discharge capacity, the greater the expansion and contraction of the electrode plate that accompanies charging / discharging, and the need for a binding force at the interface of the current collector. In the above-mentioned prior art patent documents, if the surface of the metal foil is a concave, the opposite back surface is inevitably a convex, and the metal foil is prevented from wavy, wrinkled, warped and the like when forming the irregularities. It had the problem that it was difficult.

  Moreover, in the prior art of patent document 2 mentioned above, a metal foil is irradiated with a laser to locally heat and evaporate the metal to form a recess, and the irradiation is continuously performed on the entire surface of the metal foil. Although it is possible to form uneven portions, it is difficult to prevent undulations, wrinkles and warpage on the metal foil due to local heat applied above the metal melting point because the laser is scanned on the line, Further, when laser processing is performed on a metal foil having a thickness of 20 μm or less, such as a current collector of a lithium secondary battery, there may be a problem that holes are formed in the metal foil due to variations in laser output.

  Moreover, in the prior arts of Patent Document 3 and Patent Document 4 described above, if the surface of the metal foil is a recess, the opposite back surface is inevitably a convex portion, and the corrugated metal foil is formed when the uneven portion is formed. It is difficult to prevent the occurrence of wrinkles, warps and the like.

  Moreover, in the prior art of the above-mentioned patent document 5, since the uneven | corrugated | grooved part is formed in the punching metal of 20% or less of aperture ratio by embossing, the intensity | strength of a collector falls and it may cause the malfunction which an electrode plate cuts. .

  Further, in the above-described prior art disclosed in Patent Document 6, (surface roughness Ra of electrode active material mixture layer) − (surface roughness Ra of current collector) on a current collector made of a metal that is not alloyed with lithium. By setting the value to 0.1 μm or less, the binding force between the current collector and the electrode active material mixture layer is stabilized, but in a metal in which the expansion coefficient of the electrode active material mixture layer increases when lithium intercalates. In this case, the binding force between the current collector and the electrode active material mixture layer becomes weak, wrinkles are generated on the electrode plate, and the charge / discharge cycle characteristics may be deteriorated.

  The present invention has been made in view of the above problems, and ensures the binding force between the current collector for producing the electrode plate and the electrode active material mixture layer, and efficiently uses the electrode active material on the convex portions. It is an object of the present invention to provide a non-aqueous secondary battery current collector that can be well supported, a non-aqueous secondary battery electrode plate using the same, and a non-aqueous secondary battery.

  In order to solve the above-described conventional problems, the current collector for a non-aqueous secondary battery of the present invention is a current collector for a non-aqueous secondary battery in which at least a positive electrode active material or a negative electrode active material is supported on a strip-shaped metal foil. The metal foil is characterized in that a large number of convex portions are provided on at least one surface of the metal foil, and a surface treatment portion for increasing the binding force with the electrode active material is provided on the tip surface of the convex portion. .

  According to the current collector for a non-aqueous secondary battery of the present invention, since a large number of convex portions are provided, it is rich in flexibility and prevents waviness, wrinkles and warpage due to processing of the metal foil, and at the same time, By providing a surface treatment part that increases the binding force with the electrode active material on the tip surface of the convex part, it is possible to secure the binding force between the current collector and the electrode active material mixture layer and to prevent the electrode active material from falling off. And a highly reliable non-aqueous secondary battery can be obtained.

  In the first invention of the present invention, there is provided a current collector for a non-aqueous secondary battery in which at least a positive electrode active material or a negative electrode active material is supported on a strip-shaped metal foil, and a large number of current collectors are provided on at least one surface of the metal foil. In addition, the electrode active material of the electrode plate is highly resistant to bending stress such as winding by providing a surface treatment portion that increases the binding force with the active material on the tip surface of the convex portion. It is possible to provide a safe and high-quality non-aqueous secondary battery current collector that does not fall out of the battery.

  In the second invention of the present invention, since the surface treatment portion of the convex portion is a fine protrusion, the anchor effect acts on the binding between the current collector and the electrode active material mixture layer, and the non-sticking force is high. A current collector for an aqueous secondary battery can be provided.

  In the third invention of the present invention, the fine protrusions of the surface treatment part of the protrusions are regular protrusions, so that the binding force between the current collector and the electrode active material mixture layer is made uniform. Therefore, it is possible to provide a current collector for a non-aqueous secondary battery with stable quality.

  In the fourth invention of the present invention, even if a force that peels or drops the electrode active material mixture layer works by the fact that the fine protrusions of the surface treatment part of the protrusions are irregular protrusions, It is possible to provide a non-aqueous secondary battery current collector with good binding properties that can stop the propagation of force in the middle.

  In the fifth invention of the present invention, the fine protrusions of the surface treatment part of the convex part have a height of 1 to 5 μm, thereby increasing the binding area between the current collector and the electrode active material mixture layer. It is possible to provide a current collector for a non-aqueous secondary battery that can increase the adhesion and suppress the electrode active material from falling off.

  In the sixth aspect of the present invention, the fine protrusions of the surface treatment portion of the convex portion have a pitch of 1 to 5 μm, so that a large number of fine protrusions can be formed on the entire front surface of the convex portion. It is possible to provide a current collector for a non-aqueous secondary battery having a high anchor effect.

  In a seventh aspect of the present invention, there is provided a method for producing a current collector for a non-aqueous secondary battery in which at least a positive electrode active material or a negative electrode active material is supported on a strip-shaped metal foil, wherein at least one of the current collectors A plurality of convex portions formed on the surface of the surface and a surface treatment portion formed on the tip surface of the convex portion to increase the binding force with the electrode active material are passed between the pair of rollers formed with the concave portions twice or more. By forming it, it becomes possible to easily form a convex portion having a predetermined dimension and a surface treatment portion that enhances the binding force with the electrode active material on the tip surface of the convex portion.

In the eighth aspect of the present invention, the surface treatment portion is formed by the concave portions of the pair of rollers that pass through the first time, and the convex portion is formed by the concave portion of the pair of rollers that passes through the second time. It is possible to form a fine protrusion of the surface treatment on the tip surface portion of the convex portion of the current collector that has passed through.

  In the ninth aspect of the present invention, by using a roller in which the concave portion is formed by any one of laser processing, etching processing, dry etching processing, and blast processing, the height is 1 to 5 μm and the pitch is 1 to 5 μm. Fine protrusions can be formed on the roller surface.

  In the tenth invention of the present invention, a large number of convex portions are formed on at least one surface of the strip-shaped metal foil, and a surface treatment portion that increases the binding force with the electrode active material is formed on the tip surface of the convex portion. The electrode plate for a non-aqueous secondary battery in which at least a positive electrode active material or a negative electrode active material is supported on a current collector for a non-aqueous secondary battery makes the positive electrode active material or the negative electrode active material have excellent binding properties. Thus, it is possible to provide an electrode plate in which the positive electrode active material or the negative electrode active material does not fall off even when the electrode active material mixture layer expands or contracts repeatedly during winding or charging / discharging.

  In the eleventh aspect of the present invention, a large number of convex portions are formed on at least one surface of the band-shaped metal foil, and a surface treatment portion that increases the binding force with the electrode active material is formed on the tip surface of the convex portion. A non-aqueous electrode group constituted by winding or laminating an electrode plate carrying at least a positive electrode active material or a negative electrode active material and a counter electrode plate on a current collector for a non-aqueous secondary battery via a separator By being enclosed in the battery case together with the electrolytic solution, a highly reliable non-aqueous secondary battery can be provided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram of a current collector for a non-aqueous secondary battery in an embodiment of the present invention. FIG. 1A shows a fine surface treatment portion provided with a large number of convex portions 2 on the surface of a current collector 1B made of a metal foil and increasing the binding force with the electrode active material on the tip surface of the convex portion 2. It is the figure which provided the protrusion part 3 regularly. The protrusions 2 are arranged in a line at a pitch P1 at equal intervals in the width direction of the current collector 1B made of metal foil, and the row units L1 are arranged at equal intervals at a pitch P2 in the longitudinal direction of the current collector 1B made of metal foil. However, the present invention is not limited to this, and the interval for shifting the row unit L1 can be arbitrarily changed.

  At this time, a large number of convex portions 2 are formed on the surface of the current collector 1 </ b> B made of metal foil, and a regular fine treatment is a surface treatment portion that increases the binding force with the electrode active material on the tip surface of the convex portion 2. The height of the protrusions 3 is preferably 1 to 5 μm and the pitch is preferably 1 to 5 μm. If the height is 1 μm or less, the contact area between the current collector and the electrode active material cannot be increased so much that the binding force cannot be improved. If the height is 5 μm or more, the depth of the recess on the roller surface is 5 μm or more. When a laser is used, if the beam is focused small, the depth of focus becomes shallow, so the depth of the recess on the roller surface is deeply processed. This is because it is difficult.

  Also, if the pitch is 1 μm or less, the regular fine protrusions 3 cannot be realized unless they are very small, and the regular fine protrusions 3 themselves are weak in strength and difficult to maintain the shape, and the pitch is 5 μm or more. If it is increased, the contact area between the current collector 1B made of metal foil and the electrode active material cannot be increased so much and the binding force cannot be improved. In order to increase the binding force, it is necessary to repeat the projections of the regular fine projections 3 with a large distance between the projections, and the result is that the height is 1 to 5 μm and the pitch is 1 to 5 μm. Met. In addition, since the fine protrusions 3 are regularly arranged as in this time, the binding force between the current collector 1B made of metal foil and the electrode active material mixture layer can be made uniform, and the quality is stabilized. I was able to.

FIG. 1B shows a fine surface treatment portion provided with a large number of convex portions 2 on the surface of a current collector 1B made of a metal foil, and increasing the binding force with the electrode active material on the tip surface of the convex portion 2. It is the figure which provided the protrusion 4 irregularly. The convex portions 2 are arranged in a line at a pitch P3 at equal intervals in the width direction of the current collector 1B made of metal foil, and the row units L2 are arranged at equal intervals in the longitudinal direction of the current collector 1 made of metal foil at a pitch P4. However, although the line unit L2 is shifted by a half interval, the present invention is not limited to this, and the interval for shifting the line unit L2 can be arbitrarily changed.

  At this time, a large number of convex portions 2 are formed on the surface of the current collector 1B made of metal foil, and the surface of the convex portion 2 is irregularly fine that is a surface treatment portion that increases the binding force with the electrode active material. The height of the protrusion 4 is preferably 1 to 5 μm. When etching, dry etching, or blasting is used, the entire processed surface is roughened, and it is difficult to control only the height and pitch, and the processing states are irregularly arranged. Therefore, if the height is 1 μm or less, the contact area between the current collector 1 made of metal foil and the electrode active material cannot be increased so much that the binding force cannot be improved. On the other hand, if the height is as large as 5 μm or more, the strength of the irregular fine protrusions 4 itself becomes weak at a portion where the processing interval is fine, and it becomes difficult to maintain the shape.

  In order to increase the binding force, it is necessary to repeat the protrusions and protrusions of the irregular fine protrusions 4 at irregular intervals and repeatedly, and for that purpose, a height of 1 to 5 μm is a very good result. there were. Moreover, even if the irregular fine protrusions 4 are arranged like this time, even if the force for peeling or dropping the current collector 1B made of metal foil and the electrode active material mixture layer works, the fine protrusions 4 However, because of the irregularity, the propagation of force could be stopped in the middle, and the current collector 1B made of metal foil could be made because of its good binding property.

  As a method of manufacturing the current collector 1B made of these metal foils, first, a surface treatment portion that increases the binding force of the current collector of the electrode plate for a non-aqueous secondary battery to the electrode active material is formed into a regular fine protrusion. As a processing roller for forming the portion 3, a concave portion 6 is formed on the surface of the metallic processing roller 5 shown in FIG. 2 (a) by laser processing as shown in FIG. 2 (b). . The recesses 6 are arranged in a line at equal intervals with a pitch P5 as row units L3 in the longitudinal direction of the processing roller 5 in FIG. 2A, and the row units L3 are arranged in the circumferential direction of the processing roller 5. Were sequentially arranged at a pitch P6 of the respective recesses 6 arranged in a row. In the embodiment of the present invention, an embodiment in which the above-described row unit L3 is shifted by a half interval is disclosed, but the present invention is not limited to this, and the interval by which the row unit L3 is shifted is disclosed. Can be set arbitrarily.

  Further, as a processing roller for forming the surface treatment portion for enhancing the binding force between the current collector and the electrode active material with the irregular fine protrusions 4, the metal processing shown in FIG. As shown in FIG. 2C, the concave portions 7 could be irregularly formed on the surface of the roller 5 using an etching process, a dry etching process, a blast process, or the like in addition to the laser process.

  As a processing roller used for forming a large number of convex portions 2 on at least one surface of the current collector, laser processing is performed on the surface of the metallic convex portion processing roller 8 as shown in FIG. The concave portion 9 was formed as shown in FIG. The concave portions 9 are arranged in a line at equal intervals with a pitch P9 as the row unit L5 in the longitudinal direction of the convex portion processing roller 8 of FIG. The concave portions 9 arranged in the circumferential direction were sequentially arranged at a pitch P10. In the embodiment of the present invention, an embodiment in which the above-described row unit L5 is shifted by a half interval is disclosed, but the present invention is not limited to this, and the interval by which the row unit L5 is shifted is disclosed. Can be set arbitrarily.

A large number of convex portions 2 are formed on the current collector of the electrode plate for the non-aqueous secondary battery, and the surface treatment portion that increases the binding force with the electrode active material is formed on the tip surface of the convex portion 2. As shown in FIG. 5, a concave portion for forming regular fine protrusions 3 which are surface-treated portions that enhance the binding force with the electrode active material is applied as shown in FIG. The current collector 1 made of a metal foil was passed through the gap between the upper roller 15 for processing and the lower roller 25 for processing, which was a pair of rollers, to form the current collector 1A made of the metal foil over the entire surface.

  At this time, when the regular recesses 6 are formed on the surfaces of the processing upper roller 15 and the processing lower roller 25 as shown in FIG. 2B, the current collector 1A made of a metal foil has the structure shown in FIG. As shown in FIG. 3A, the current collector surface 1A is formed on the entire surface, which is formed of regular fine protrusions 3 which are surface-treated portions that enhance the binding force with the electrode active material and metal foil of the surface-treated portions. It became. The regular minute protrusions 3 are arranged in a line at a pitch P7 at equal intervals in the width direction of the current collector, and the row units L4 are arranged at equal intervals in the longitudinal direction of the current collector at a pitch P8. Although the unit L4 is shifted by a half interval, the present invention is not limited to this, and the interval by which the row unit L4 is shifted can be arbitrarily changed.

  Similarly, in order to form the surface treatment portion with the irregular fine protrusions 4, the irregularities as shown in FIG. 2C are formed on the surfaces of the processing upper roller 15 and the processing lower roller 25 shown in FIG. When the regular recesses 7 are formed, the current collector 1A made of a metal foil has an irregular fine protrusion that is a surface treatment portion that increases the binding force with the electrode active material on the surface as shown in FIG. The collector surface 1A made of the metal foil of the portion 4 and the surface treatment portion was formed on the entire surface.

  As described above, after forming the regular fine protrusions 3 that are the surface treatment portions that enhance the binding force of the current collector 1A made of the metal foil shown in FIG. A regular fine protrusion that is a surface treatment portion that enhances the binding force between the electrode active material and the gap between the convex processing upper roller 18 and the convex processing lower roller 28 that are a pair of rollers provided with a plurality of concave portions. The surface treatment part which forms the convex part 2 of arbitrary shapes when the collector 1A which consists of metal foil which formed the part 3 passes, and raises the binding force with an electrode active material on the front-end | tip surface of the convex part 2 It was possible to produce a current collector 1B made of a metal foil forming regular fine protrusions 3.

  The surface of the current collector 1B made of metal foil has a binding force with the electrode active material on the tip surface of the protrusion 2 as shown in FIG. In this state, the regular fine protrusions 3 that are surface treatment portions that improve the surface are regularly formed. In addition, the regular fine protrusions 3 which are the surface treatment portions originally formed on the entire surface of the current collector remain only at the tip surface of the convex portion 2, and the surface portion of the current collector 1B made of another metal foil is convex. The part processing upper roller 18 and the convex part processing lower roller 28 are crushed and disappear.

  This is because, when passing through the convex processing upper roller 18 and the convex processing lower roller 28 that form a large number of convex portions 2 in the second time shown in FIG. The shape of the regular fine protrusions 3 that are the surface treatment portions remains, but the portions other than the concave portions of the roller are pressed by the rollers, and the regular fine protrusions 3 that are the surface treatment portions are crushed. It is. In addition, as a method of forming the convex part 2 on the surface of the current collector and forming the surface treatment part that increases the binding force with the electrode active material on the tip surface of the convex part 2, the method described above is limited. Instead, for example, the current collector 1 made of metal foil may be sandwiched between the upper mold and the lower mold by using a mold or the like instead of the roller, and may be compressed.

As described above, at least the positive electrode active material on the current collector 1 </ b> B made of the metal foil in which the regular fine protrusions 3 that are the surface treatment portions that enhance the binding force with the electrode active material are formed on the tip surface of the protrusions 2. As a means for supporting the material or the negative electrode active material, there is a method in which a paint containing these electrode active materials is applied to the current collector 1B made of a metal foil, and this book using the electrode plate for a non-aqueous secondary battery As the nonaqueous secondary battery of the invention, for example, as shown in FIG. 6, a positive electrode plate 64 using a composite lithium oxide as an electrode active material and a negative electrode plate 66 using a material capable of holding lithium as an electrode active material are separators. An electrode group 63 wound in a spiral shape via 68 was produced. Next, the electrode group 63 is accommodated in the bottomed cylindrical battery case 60 together with the insulating plate 69, the negative electrode lead 67 led out from the lower part of the electrode group 63 is connected to the bottom of the battery case 60, and then the electrode group The positive electrode lead 65 led out from the upper part of 63 is connected to the sealing plate 61, and a predetermined amount of an electrolyte solution (not shown) made of a non-aqueous solvent is injected into the battery case 60. A sealing plate 61 with 62 attached to the periphery can be inserted, and the opening of the battery case 60 can be bent inward and caulked and sealed.

  As the positive electrode plate 64, a positive electrode active material, a conductive material, and a binder are placed in an appropriate dispersion medium, and mixed and dispersed by a dispersing machine such as a planetary mixer to increase the binding force with the electrode active material. A certain positive fine protrusion 3 is kneaded by adjusting the viscosity to be optimum for application to the current collector 1B made of a metal foil formed on the tip surface of the protrusion 2, thereby preparing a positive electrode mixture paint.

  As the positive electrode active material at this time, for example, lithium cobaltate and modified products thereof (such as lithium cobaltate in which aluminum or magnesium is dissolved), lithium nickelate and modified products thereof (partially nickel is substituted with cobalt) Composite oxides such as lithium manganate and modified products thereof.

  As a material type of the conductive material at this time, for example, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, and various graphites may be used alone or in combination.

  As the binder for the positive electrode at this time, for example, polyvinylidene fluoride (PVdF), a modified polyvinylidene fluoride, polytetrafluoroethylene (PTFE), a rubber particle binder having an acrylate unit, and the like can be used. At this time, an acrylate monomer or an acrylate oligomer into which a reactive functional group is introduced can be mixed in the binder.

  The positive electrode mixture paint prepared as described above is applied onto an aluminum foil using a die coater, then dried and then compressed to a predetermined thickness by a press to obtain a positive electrode plate.

  The negative electrode plate 66 is a rule that is a surface treatment unit that puts a negative electrode active material and a binder in an appropriate dispersion medium, and mixes and disperses the mixture with a dispersing machine such as a planetary mixer to increase the binding force with the electrode active material. The negative viscosity paint is prepared by adjusting the viscosity to be optimal for application to the current collector 1B made of a metal foil in which the fine protrusions 3 are formed on the tip surface of the protrusions 2.

  As the negative electrode active material at this time, various natural graphites and artificial graphites, silicon-based composite materials such as silicide, and various alloy composition materials can be used.

  Various binders such as PVdF and modified products thereof can be used as the negative electrode binder at this time. From the viewpoint of improving lithium ion acceptability, styrene-butadiene copolymer rubber particles (SBR) and modified products thereof are used. In addition, it can be said that it is more preferable to use a cellulosic resin including carboxymethyl cellulose (CMC) or the like in combination or to add a small amount.

  A negative electrode plate is obtained by applying the negative electrode mixture paint produced as described above onto a copper foil using a die coater, and then compressing to a predetermined thickness with a press after drying.

Further, at least the positive electrode on the current collector 1B made of the metal foil in which the regular fine protrusions 3 that are the surface treatment portions that enhance the binding force with the electrode active material as described above are formed on the tip surface of the protrusions 2. As another means for supporting the active material or the negative electrode active material, a vacuum process in which these electrode active materials can be selectively supported on specific parts of the current collector can be used. It is more preferable to form a column shape mainly on the convex portion 2. This is because the regular fine protrusions 3 which are surface-treated portions that enhance the binding force with the electrode active material are formed on the tip surface of the convex portions 2, so that the uneven portions of the surface-treated portions have a contact area. The anchor effect is increased and an electrode active material thin film can be formed on the upper surface of the convex portion 2 with high accuracy and the lithium ion is occluded by forming the electrode active material thin film in a columnar shape. This is because the effect of relaxing the volume expansion of the thin film can be expected.

  A thin film of an electrode active material is formed on a current collector 1B made of a metal foil in which regular fine protrusions 3 that are surface treatment portions that enhance the binding force with the electrode active material are formed on the tip surface of the protrusions 2. The means is not particularly limited as long as it is a vacuum process, but a dry process such as an evaporation method, a sputtering method, or a CVD method can be used.

  As the electrode active material at this time, for example, Si, Sn, Ge, Al or an alloy thereof, an oxide such as SiOx or SnOx, SiSx, SnS, or the like can be used as the negative electrode active material. It is preferable that Further, a thin film of the electrode active material is deposited on the current collector 1B made of a metal foil in which regular fine protrusions 3 that are surface treatment portions that enhance the binding force with the electrode active material are formed on the tip surface of the protrusions 2. The thickness varies depending on the required characteristics of the non-aqueous secondary battery to be manufactured, but is preferably in the range of 5 to 30 μm, more preferably in the range of 10 to 25 μm.

  The separator 68 is not particularly limited as long as it can withstand the use range of the non-aqueous secondary battery, but a microporous film of an olefin resin such as polyethylene or polypropylene may be used singly or in combination. It is general and preferred as an embodiment. The thickness of the separator is not particularly limited, but may be 10 to 25 μm.

Moreover, for the electrolytic solution, it is possible to use various lithium compounds such as LiPF ₆ and LiBF ₄ as an electrolyte salt. Further, ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (MEC) can be used alone or in combination as a solvent. It is also preferable to use vinylene carbonate (VC), cyclohexylbenzene (CHB), or a modified product thereof in order to form a good film on the positive electrode plate or the negative electrode plate, or to ensure stability during overcharge. Note that the surface treatment portion for forming the convex portion 2 on the surface of the current collector and increasing the binding force with the electrode active material on the tip surface of the convex portion 2 is not limited to the above-described method. Even when the surface treatment portion is formed by porous etching, dry etching, or blasting, it is possible to increase the binding force with the electrode active material.

  FIG. 2A shows the processing roller 5 shown in FIG. 2 (a) as a roll for forming a surface-treated portion with a regular fine protrusion 3 that enhances the binding force with an electrode active material having a height of 3 μm and a pitch of 3 μm. As shown in b), the circular recesses 6 having the same shape are arranged on the surface of the pair of upper and lower rollers by laser processing so as to be arranged in a specific pattern at the current collector width direction pitch P5 and the current collector longitudinal direction pitch P6. . Next, as a roller for forming the convex portion 2, the convex portion processing roller 8 in FIG. 4 (a) has a current collector width direction pitch P9 as shown in FIG. 4 (b), and the current collector longitudinal pitch P10 is 20 μm. A substantially circular recess 9 having the same shape was applied to the surfaces of a pair of upper and lower rollers in a specific pattern. As shown in FIG. 5, the two types of upper and lower pairs of rollers shown in FIG. 2 (a) are arranged on the upper side of the processing roller 5 with a fine processing pitch, and then the convex processing roller 8 shown in FIG. Was placed downstream.

A copper foil having a thickness of 20 μm was used as the current collector 1 made of a metal foil, and the copper foil was sequentially passed while pressing between a pair of upper and lower rollers. The copper foil current collector 1A that has passed the first time passes between the upper processing roller 15 and the lower processing roller 25 while being pressed, so that the surface has a height as shown in FIG. Regular fine protrusions 3 are formed which are surface-treated portions that increase the binding force with an electrode active material having a pitch of 3 μm and a pitch of 3 μm. Next, the surface of the copper foil current collector 1 </ b> B is shown in FIG. 1 (a) by continuously passing through the second portion between the convex processing upper roller 18 and the convex processing lower roller 28 while being pressurized. Thus, a current collector 1B made of copper foil having a total thickness of 28 μm in which regular fine protrusions 3 that are surface-treated portions that enhance the binding force with the electrode active material were formed on the tip surface of the protrusions 2 was prepared.

Next, silicon having a purity of 99.9999% is used as a target, and a regular fine protrusion is a surface treatment portion that increases the binding force with the electrode active material on the tip surface of the convex portion 2 by a vapor deposition apparatus equipped with an electron beam heating means. Deposition was carried out while introducing oxygen of 99.7% purity on both sides of the copper foil current collector 1B shown in FIG. 1 (a) in which the portion 3 was formed, and SiO _0.5 having a thickness of 10 μm was formed on the convex portion. After forming, the negative electrode plate was produced by slitting to a specified width.

The copper foil current collector 1B formed with such an array of convex portions 2 has the substantially elliptical convex portions 2 arranged in the width direction of the current collector 1B. When the negative electrode active material is vapor-deposited in the longitudinal direction, it can be efficiently attached onto the convex portion 2 and the electrode active material having a height of 3 μm and a pitch of 3 μm on the tip surface of the convex portion 2 Since it has regular fine protrusions 3 which are surface treatment portions that enhance the binding force, a negative electrode active material layer is deposited on a copper foil current collector 1B to produce a negative electrode plate, or When slitting to a predetermined width, the fixing area of the copper foil current collector 1B and SiO _0.5 was increased, and the fixing power was high, and the negative electrode active material layer could be prevented from falling off. In order to increase the binding force, it is necessary to repeat the protrusions of the regular fine protrusions 3 with a large distance between the protrusions, and the result is that the height is 3 μm and the pitch is 3 μm.

  Below, the height and pitch of the regular fine protrusions 3 which are surface treatment portions for increasing the binding force with the electrode active material on the tip surface of the convex portion 2 are 0.5 μm, 1 μm, 3 μm, 5 μm, 8 μm, 10 μm. The peel strength between the copper foil current collector 1B and the electrode active material of the sample electrode plate produced by varying the amount of the electrode active material after 100 cycles of charge / discharge of the sample coin cell produced using this sample electrode plate 1B Indicate the presence or absence of peeling.

As shown in (Table 1), an electrode plate having a height and a pitch of 1 μm to 5 μm exhibits a peel strength of 25 kgf / cm ² or more, and a sample coin cell is produced and peeling of the electrode active material after 100 cycles of charge / discharge occurs. It was confirmed that a regular fine protrusion 3 was formed as a surface treatment portion for enhancing the binding force with an electrode active material having a height of 3 μm and a pitch of 3 μm. As shown in FIG. 2 (c), the processing roller 5 as a roll having a surface treatment portion for increasing the binding force with the electrode active material having a pitch of 1-5 μm and a pitch of 1-5 μm is shown in FIG. 2 (c). The surface of the pair of upper and lower rollers was blasted so that the concave portions 7 were irregularly arranged in the longitudinal direction of the current collector.

Next, as a roller for forming the convex portion, the convex portion processing roller 8 shown in FIG. 4A has a current collector width direction pitch P9 as shown in FIG. 4B, and the current collector longitudinal direction pitch P10 is all 20 μm. The substantially circular recesses 9 having the same shape are formed in a specific pattern on the surface of a pair of upper and lower rollers, and these two types of upper and lower pair of rollers are processed as shown in FIG. 4 (a), the convex processing roller 8 having a large processing pitch is disposed downstream, and the surface of the processed copper foil is placed on the tip surface of the convex portion as shown in FIG. 1 (b). A similar result was obtained even when a 28 μm thick copper foil current collector 1B having irregular fine protrusions 4 which are surface-treated portions that enhance the binding force with the substance was produced.

  An embodiment of a non-aqueous secondary battery using the electrode plate for a non-aqueous secondary battery of the present invention will be described below. First, 100 parts by weight of lithium cobaltate in which a part of cobalt is substituted with nickel and manganese as the positive electrode active material, 2 parts by weight of acetylene black as the conductive material with respect to 100 parts by weight of the electrode active material, and polyfluoride as the binder After preparing a positive electrode mixture paint by stirring and kneading vinylidene with 2 parts by weight of 100 parts by weight of an electrode active material together with an appropriate amount of N-methyl-2-pyrrolidone in a double-arm kneader. The positive electrode mixture paint is applied on both sides of the aluminum foil of the current collector and dried, then pressed to a total thickness of 126 μm, and slitted to the width specified by the cylindrical lithium ion secondary battery shown in FIG. A positive electrode plate 64 was produced.

Next, a copper foil current collector was prepared in the same manner as in Example 1, and a vapor deposition apparatus equipped with electron beam heating means using 99.9999% purity silicon as the negative electrode active material, as in Example 1. Then, vapor deposition was performed while introducing oxygen having a purity of 99.7% on both sides of the copper foil current collector 1 on which the convex portion 2 having a height of 8 μm shown in FIG. 1A was formed, and a film was formed on the convex portion 2. After forming SiO _0.5 with a thickness of 10 μm in a columnar shape, slitting was performed to a width defined by the cylindrical lithium ion secondary battery shown in FIG.

  Further, as shown in FIG. 6, an electrode group 63 in which a positive electrode plate 64 and a negative electrode plate 66 are spirally wound through a separator 68 is manufactured, and then the electrode group 63 is used as a bottomed cylindrical battery case 60. Is connected to the bottom of the battery case 60, and then the positive lead 65 led out from the upper part of the electrode group 63 is connected to the sealing plate 61. After injecting a predetermined amount of an electrolyte solution (not shown) made of a non-aqueous solvent into the battery case 60, a sealing plate 61 with a sealing gasket 62 attached to the periphery is inserted into the opening of the battery case 60, and the battery case 60 is inserted. The non-aqueous secondary battery was produced by bending the opening of the inside and crimping it inward.

  After producing the spirally wound electrode group 63 in the non-aqueous secondary battery, the electrode group 63 was disassembled and observed. As a result, both the positive electrode plate 64 and the negative electrode plate 66 were broken, the electrode active material layer was dropped, etc. No defects were found. Furthermore, this non-aqueous secondary battery was charged and discharged for 300 cycles. However, when the non-aqueous secondary battery and the electrode group 63 were disassembled after 300 cycles with no cycle deterioration, defects such as lithium deposition and electrode active material layer dropping were recognized. I couldn't.

  This is because the electrode active material is formed on the upper surface where the regular fine protrusions 3 are formed on the surface of the tip of the convex portion 2 to increase the binding force with the electrode active material having a height of 3 μm and a pitch of 3 μm. The contact area between the copper foil current collector 1B and the electrode active material is increased by forming the thin film in a columnar shape, and the expansion of the thin film of the electrode active material when lithium is occluded and of the electrode active material when lithium is released It is considered that good battery characteristics were maintained with a decisive force comparable to the volume change due to the shrinkage of the thin film.

In addition, instead of the regular fine protrusions 3 which are surface treatment portions that increase the binding force with the electrode active material having a height of 3 μm and a pitch of 3 μm on the tip surface of the convex portion 2, as shown in FIG. A collection of copper foils on which irregular fine protrusions 4 are formed on the tip surface of the protrusions 2, which are surface-treated portions that increase the binding force with an electrode active material having a height of 1 to 5 μm and a pitch of 1 to 5 μm. After the electric conductor 1B was produced and the negative electrode plate was produced by the method described above, the same result was obtained even if a non-aqueous secondary battery was produced and charged and discharged for 300 cycles as shown in FIG. . As described above, the contact area between the copper foil current collector 1B and the electrode active material is increased by the surface treatment portion that increases the binding force with the electrode active material having a height of 1 to 5 μm and a pitch of 1 to 5 μm. This is thought to be due to increased wearing power.

  As described above, the electrode plate for a non-aqueous secondary battery according to the present invention has the convex portion 2 formed on the surface of the current collector 1B made of metal, the height of 1-5 μm on the tip surface of the convex portion 2, and the pitch. By forming the regular fine protrusions 3 or the irregular fine protrusions 4 which are surface treatment parts that enhance the binding force with the electrode active material of 1 to 5 μm, the current collector 1B made of metal foil and In the post-process such as the step of supporting the electrode active material on the convex part 2 of the current collector 1B made of metal foil and the slit processing to a predetermined width after the anchor effect is increased in the binding with the electrode active material mixture layer Can also prevent the electrode active material from falling off. Furthermore, the regular protrusion 3 which is a surface treatment part which raises the binding force with the electrode active material whose height is 1-5 micrometers and a pitch is 1-5 micrometers on the front-end | tip surface of the convex part 2 of the collector 1B which consists of metal foils. Or, since the irregular fine protrusions 4 are formed, the adhesion between the current collector 1B made of metal foil and the electrode active material formed as a thin film can be increased, which is considered to be very effective.

  The current collector and electrode plate used in the non-aqueous secondary battery according to the present invention ensure the strength of the current collector for producing the electrode plate, and on the tip surface of the convex portion formed on the current collector. By forming a surface treatment portion that increases the binding force with an electrode active material having a height of 1 to 5 μm and a pitch of 1 to 5 μm, the electrode active material can be efficiently and highly loaded, and reliable. Since a high non-aqueous secondary battery can be obtained, it is useful as a portable power source or the like that is desired to have a higher capacity as the electronic device and communication device become multifunctional.

(A) The perspective view which shows the principal part of the electrical power collector which formed the surface treatment part in the front end surface of the convex part which concerns on embodiment of this invention with the regular fine protrusion, (b) Implementation of this invention The perspective view which shows the principal part of the electrical power collector which formed the surface treatment part in the front surface of the convex part which concerns on a form with the irregular fine protrusion. (A) The perspective view which shows the processing roller which forms the surface treatment part which concerns on embodiment of this invention, (b) The surface of the processing roller which forms the regular surface treatment part which concerns on embodiment of this invention The enlarged perspective view of the principal part which shows the surface of the processing roller which forms the irregular surface treatment part which concerns on embodiment of this invention, (c) (A) The perspective view which shows the surface of the principal part of the electrical power collector which gave the surface treatment part which concerns on embodiment of this invention with the regular fine protrusion, (b) The surface which concerns on embodiment of this invention The perspective view which shows the surface of the principal part of the electrical power collector which gave the process part with the irregular fine protrusion (A) The perspective view which shows the processing roller which forms the convex part which concerns on embodiment of this invention, (b) Of the principal part which shows the surface of the processing roller which forms the convex part concerning embodiment of this invention Enlarged perspective view The perspective view which shows the roller process to the electrical power collector which concerns on embodiment of this invention 1 is a partially cutaway perspective view of a cylindrical secondary battery according to an embodiment of the present invention. Sectional drawing which shows the state of uneven | corrugated processing to the electrical power collector in a prior art example (A) Perspective view of metal foil having corrugated plate-like irregularities in conventional example, (b) Perspective view of metal foil having pyramidal irregularities in the conventional example, (c) Conventional example The perspective view which looked at the metal foil which has a pyramid-shaped unevenness | corrugation part in from the bottom, (d) The perspective view which looked at another metal foil which has a pyramid-shaped unevenness | corrugation part in the same prior art example, (e) The said prior art example The perspective view which looked at another metal foil which has a pyramid-shaped uneven part in from the bottom (A) Sectional view of current collector showing state filled with electrode active material mixture in conventional example, (b) Sectional view of current collector showing another state filled with electrode active material mixture in the conventional example (C) Sectional drawing of the electrical power collector which shows another state with which the electrode active material mixture in the same prior art example was filled

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Current collector 1A Current collector which consists of metal foils 1B Current collector which consists of metal foils 2 Convex part 3 Regular fine protrusion 4 Irregular fine protrusion 5 Processing roller 6 Concave part 7 Concave part 8 Convex part Processing roller 9 Concave 15 Processing upper roller 18 Convex processing upper roller 25 Processing lower roller 28 Convex processing lower roller 60 Battery case 61 Sealing plate 62 Sealing gasket 63 Electrode group 64 Positive electrode plate 65 Positive electrode lead 66 Negative electrode plate 67 Negative electrode lead 68 Separator 69 Insulating plate P1, P3, P5, P7, P9 Pitch of projections in width direction P2, P4, P6, P8, P10 Pitch of projections in longitudinal direction L1, L2, L3, L4, L5 Line unit in the width direction of the electric body

Claims (11)

  A current collector for a non-aqueous secondary battery supporting at least a positive electrode active material or a negative electrode active material on a band-shaped metal foil, provided with a plurality of protrusions on at least one surface of the metal foil, and A current collector for a non-aqueous secondary battery, wherein a surface treatment portion for increasing the binding force with an active material is provided on the tip surface of the convex portion.   The current collector for a non-aqueous secondary battery according to claim 1, wherein the surface treatment portion is a fine protrusion.   The current collector for a non-aqueous secondary battery according to claim 1, wherein the fine protrusions of the surface treatment part are regular protrusions.   The current collector for a non-aqueous secondary battery according to claim 1, wherein the fine protrusions of the surface treatment part are irregular protrusions.   The current collector for a non-aqueous secondary battery according to claim 1, wherein the height of the fine protrusions of the surface treatment portion is 1 to 5 μm.   The current collector for a non-aqueous secondary battery according to claim 1, wherein the pitch of the fine protrusions of the surface treatment portion is 1 to 5 μm.   A method for producing a current collector for a non-aqueous secondary battery in which at least a positive electrode active material or a negative electrode active material is supported on a band-shaped metal foil, wherein a plurality of protrusions are formed on at least one surface of the current collector; The non-aqueous system is characterized in that the surface treatment part formed to increase the binding force with the active material on the tip surface of the convex part is formed by passing between the pair of rollers having the concave part twice or more. A method for producing a current collector for a secondary battery.   The non-aqueous system according to claim 7, wherein a surface treatment portion is formed by the concave portions of the pair of rollers that pass through the first time, and a convex portion is formed by the concave portions of the pair of rollers that pass through the second time. A method for producing a current collector for a secondary battery.   8. The method of manufacturing a non-aqueous secondary battery according to claim 7, wherein a roller in which the concave portion is formed by any one of laser processing, etching processing, dry etching processing, and blast processing is used.   An electrode plate for a non-aqueous secondary battery, wherein at least a positive electrode active material or a negative electrode active material is supported on the non-aqueous secondary battery current collector according to any one of claims 1 to 6.   The electrode plate which becomes a counter electrode with the electrode plate for non-aqueous secondary batteries which carry | supported at least the positive electrode active material or the negative electrode active material on the collector for non-aqueous secondary batteries as described in any one of Claims 1-6 A non-aqueous secondary battery comprising a battery case in which an electrode group formed by winding or laminating a battery with a separator is enclosed together with an electrolytic solution.

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