JP2011187270A - Method of manufacturing electrode for lithium secondary battery, and manufacturing method of lithium secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that when a collector is broken in pressing and forming a lithium battery electrode in which a porus sheet is used as the collector, and an auxiliary base material is used, a volume ratio of active material decreases and volume energy density also decreases. <P>SOLUTION: An expanded metal 100 having a mesh width of a long direction 101 and a short direction 102 is used as the collector, and mixture containing the active material is press-fitted in a mesh opening from a direction at 45°or less with respect to the short direction 102. Alternatively, an electrode precursor with the mixture containing the active material filled in the expanded metal 100 is rolled from a direction at 45°or less with respect to the short direction 102. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing an electrode for a lithium secondary battery using an expanded metal as a current collector, and a method for producing a lithium secondary battery using the electrode.

  A lithium secondary battery, which is a typical secondary battery, has a high energy density and excellent cycle characteristics. Lithium secondary batteries having such characteristics are mainly used as power sources for portable electrical devices.

  The shape of the lithium secondary battery is mainly cylindrical or rectangular, and batteries of various sizes are manufactured according to the application. In a commercially available cylindrical battery, a film in which a mixture containing a battery active material (hereinafter referred to as an active material layer) is applied to a metal foil as a current collector, and an active material layer is formed on the surface of the metal foil. A shaped electrode is used. A cylindrical battery is configured by winding the positive electrode and the negative electrode thus formed through a porous separator. As the rectangular battery, there are a battery in which a film-like electrode similar to the above is wound in an elliptical shape and stored in a rectangular case, and a battery in which strip-shaped electrodes are stacked. A wound battery is excellent in manufacturability, and a stacked battery is excellent in volume energy density.

  The electrode area can be increased by using the film-like electrode described above. Further, the lithium ion diffusion distance can be shortened by reducing the thickness of the active material layer. Thus, by devising the electrode structure, the wound battery can be charged and discharged at a high rate. Since the winding of the film-like electrode is relatively easy, there are many known examples regarding the winding type battery structure (for example, see Patent Document 1).

  However, it is also known that the above-mentioned film-like electrodes also have drawbacks, and methods for improving them have also been proposed. For example, when the filling amount of the active material is increased using a metal foil as a current collector, it is necessary to increase the thickness of the active material layer. In such an electrode configuration, the active material is likely to be peeled off with charge / discharge. In order to suppress such a phenomenon, the blending amount of the binder in the active material layer must be increased. However, as a result, there is a problem that the utilization factor of the active material is lowered and the energy density is lowered.

  As a solution to this problem, it has been proposed to use an aluminum porous sheet as a current collector. In addition, it is said that by using an electrode using this porous sheet, it is possible to solve an insufficient strength of the electrode when producing a battery having a laminated structure, which is one of the problems of the sheet-like electrode (for example, patent document) 2).

  However, when a porous sheet is used as a current collector, there is also a problem that when pressure molding is performed in order to improve the volume energy density, the electrode is extended, and the metal fibers of the current collector are cut off so as not to function. In order to solve this problem, means has been proposed in which a metal substrate is joined to a porous sheet to increase the strength and suppress the elongation (see, for example, Patent Document 3).

  In addition, in order to improve the current collection efficiency, there is a lead-acid battery in which the active material is kneaded into the gaps of the expanded metal mesh using expanded metal whose short direction is the longitudinal direction of the electrode and inclined from the short direction as the current collector. It is disclosed (for example, see Patent Document 4).

JP-A-5-74488 JP-A-6-196170 JP-A-9-161806 International Publication No. 94/15375

  In the said conventional structure, by joining a metal base material to a porous sheet, the elongation at the time of pressure molding can be suppressed, and it can suppress that a metal fiber etc. cut. However, the volume ratio of the current collector that does not contribute to the charge / discharge capacity increases as much as the metal base material is added. For this reason, there is a problem that the effect of increasing the volume energy density, which is one of the advantages of using the porous sheet, is offset.

  Moreover, when an expanded metal is used for the current collector of the lithium secondary battery, the ionic conductivity of the electrolyte is significantly different from a lead storage battery using a sulfuric acid aqueous solution as an electrolyte. Therefore, it has been necessary to stretch the unidirectional strand of the expanded metal (the mesh portion forming the sides of the rhombic opening) by increasing the compressibility of the electrode layer and decreasing the porosity.

  The present invention solves such a conventional problem, and reduces the volume energy density due to the additional base material while increasing the volume energy density without causing the current collector to break even during pressure molding. It aims at providing the manufacturing method of the electrode which is not made to do.

  In order to solve the above conventional problems, in the present invention, an expanded metal having a mesh width in the long direction and the short direction is used as the current collector of the battery electrode. Then, a mixture containing the active material is inserted into the mesh opening from a direction within 45 ° with respect to the short direction (press-fit). Alternatively, the expanded metal is passed between two rolls rotating in an opposite direction from a direction within 45 ° with respect to the short direction of the electrode precursor filled with the mixture containing the active material in the expanded metal. Metal processing (rolling).

  According to the present invention, it is possible to control the direction of elongation of the current collector, and it is possible to suppress the current collector from being cut without adding a base material.

  According to the manufacturing method of the present invention, the volume energy density is not reduced by the additional base material, and the electrode for the lithium secondary battery having the increased volume energy density is produced without causing the problem that the current collector is cut. be able to. Moreover, a lithium secondary battery with a large volumetric energy density can be manufactured using the electrode produced in this way.

Schematic sectional view of a lithium secondary battery in an embodiment of the present invention An overhead view of an expanded metal used as an electrode current collector in an embodiment of the present invention Expanded view of expanded metal shown in FIG. The schematic side view which shows the structure of the apparatus which press-fits the mixture containing an active material to the electrical power collector for electrodes in embodiment of this invention 4 is a schematic top view showing the main part of the apparatus shown in FIG. The schematic side view which shows the structure of the apparatus which rolls the electrode precursor in embodiment of this invention Schematic top view showing the main part of the apparatus shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the contents described below as long as it is based on the basic characteristics described in this specification.

  FIG. 1 is a schematic cross-sectional view of a lithium secondary battery according to an embodiment of the present invention. Hereinafter, the manufacturing procedure of the cylindrical battery 30 will be described with reference to FIG.

  The battery 30 includes an electrode group 4 including a positive electrode 1 that is a first electrode, a negative electrode 2 that is a second electrode having a polarity opposite to that of the positive electrode 1, and a separator 3. A positive electrode lead 8 made of, for example, aluminum is connected to the positive electrode 1, and a negative electrode lead 9 made of, for example, copper is connected to the negative electrode 2. The positive electrode 1 and the negative electrode 2 are opposed to each other with the separator 3 interposed therebetween, and the electrode group 4 is formed by winding them.

  Then, the insulating plates 10A and 10B are mounted on the upper and lower sides of the electrode group 4, and the electrode group 4 is inserted into the case 5 in this state. The other end of the positive electrode lead 8 is welded to the sealing plate 6, and the other end of the negative electrode lead 9 is welded to the bottom of the case 5. Further, a nonaqueous electrolyte (not shown) that conducts lithium ions is injected into the case 5 so that the electrode group 4 contains the nonaqueous electrolyte. Thereafter, the open end of the case 5 is caulked against the positive electrode cap 16, the PTC element 18, the current interrupting member 19, and the sealing plate 6 through the gasket 7. The positive electrode cap 16 constitutes a positive electrode terminal, and the case 5 functions as a negative electrode terminal. In this way, the battery 30 can be manufactured.

The positive electrode 1 includes a current collector 1A and a positive electrode layer 1B containing a positive electrode active material. The positive electrode layer 1B contains a positive electrode active material. The positive electrode active material is not particularly limited as long as it is a material capable of electrochemically inserting and extracting lithium. For example LiMO _2: or a compound having a layered structure represented by (M a transition _metal), LiM _{2 O} 4: the use of (M a transition metal) and _Li 4 compound having a spinel structure represented by _Ti 5 _{O 12,} etc. Can do. More specifically, LiCoO ₂ , LiNiO ₂ , Li ₂ MnO ₄ or a lithium-containing composite oxide such as a mixture or composite compound thereof can be used.

  Further, the positive electrode layer 1B may further include a conductive agent and a binder. The conductive agent improves the electrical conductivity of the positive electrode layer 1B, and the binder is used to suppress peeling of the active material from the current collector 1A. As the conductive agent, for example, natural graphite or artificial graphite graphite, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, and other carbon blacks can be used. As the binder, for example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), polyethylene, polypropylene, aramid resin, polyamide, polyimide, or the like can be used.

The negative electrode 2 includes a current collector 11 and a negative electrode layer 15. As the active material of the negative electrode layer 15, a carbon material such as graphite can be used. Further, materials such as silicon (Si), tin (Sn), and alloys and oxides thereof that can electrochemically insert and desorb lithium and have a theoretical capacity density exceeding 833 mAh / cm ³ are used. It can also be used. In addition, the negative electrode layer 15 may further include a conductive agent and a binder similarly to the positive electrode layer 1B. The current collectors 1A and 11 are drawn in a uniform sheet shape, but are composed of expanded metal as will be described later.

  The separator 3 can be a microporous film or non-woven fabric of polyolefin such as polyethylene or polypropylene. The separator 3 is not essential, and the positive electrode 1 and the negative electrode 2 need not be in direct contact. For example, a porous layer containing an oxide powder such as magnesium oxide and a binder may be formed on the surface of the positive electrode 1 or the negative electrode 2. Good. Moreover, you may use such a porous layer and the separator 3 together.

As the non-aqueous electrolyte, a non-aqueous electrolyte solution in which a solute is dissolved in an organic solvent, or a so-called polymer electrolyte layer containing these and non-fluidized with a polymer can be applied. As the solute of the non-aqueous electrolyte, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAlCl ₄ , LiSbF ₆ , LiSCN, LiCF ₃ SO ₃ , LiN (CF ₃ CO ₂ ), LiN (CF ₃ SO ₂ ) _2, etc. should be used. Can do. Examples of the organic solvent that can be used include ethylene carbonate (EC), propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate (DMC), diethyl carbonate, and ethyl methyl carbonate (EMC).

  Next, the current collectors 1A and 11 of the positive electrode 1 and the negative electrode 2 will be described with reference to FIGS. FIG. 2 is an overhead view of an expanded metal that is a current collector for an electrode according to an embodiment of the present invention, and FIG. 3 is an enlarged view of the expanded metal shown in FIG.

  The expanded metal 100 has a diamond-shaped opening 200. The longer diagonal direction of the rhombus is referred to as a long direction 101, and the shorter diagonal direction is referred to as a short direction 102. Further, as shown in FIG. 3, a thin mesh portion forming a rhombus side is called a strand 203, and a thick portion where the mesh intersects is called a bond 206.

  In the present embodiment, the expanded metal 100 having the mesh width in the long direction 101 and the mesh width in the short direction 102 is used as the current collectors 1A and 11 as described above. Then, the mixture containing the active material is pressed into the mesh opening 200 from the direction 103 within 45 ° with respect to the short direction 102. Alternatively, the electrode precursor formed by filling the mesh opening 200 with the mixture containing the active material is rolled from the direction 103 within 45 ° with respect to the short direction 102.

  Hereinafter, the effect of regulating the direction of press-fitting and rolling will be described. The case where the mixture containing the active material is pressed into the expanded metal 100 along the short direction 102 in FIG. 2 and the case where the mixture containing the active material is pressed into the expanded metal 100 along the long direction 101 are shown in FIG. Conditions are set for the metal 100 to have a similar elongation. In this case, the elongation rate of the strands 203 in the expanded metal 100 is smaller in the case of press-fitting along the short direction 102 than in the case of press-fitting along the long direction 101. Therefore, if the elongation rate until the strand 203 is broken is the same, the expanded metal 100 can allow a larger elongation if it is press-fitted along the short direction 102. Therefore, it is possible to press-fit the mixture with a larger pressure by press-fitting along the short direction 102, and the volume energy density of the electrode can be improved. This is the same even if the case where the electrode precursor is rolled along the short direction 102 and the case where the electrode precursor is rolled along the long direction 101 are compared.

  The optimum press-fitting or rolling direction for exhibiting the above-described effect is the short direction 102. However, if the metal is pressed and rolled from a direction slightly deviated from the short direction 102, the expanded metal 100 can hold the mixture containing the active material from a plurality of directions. Therefore, peeling of the mixture can be suppressed. In this manner, the press-fitting or rolling direction can be changed according to the desired electrode state. The direction of press-fitting or rolling can be determined because the width 205 of the strand 203 of the expanded metal 100 is different on each side.

  As a result of the examination, by setting the direction of press-fitting or rolling to a direction 103 within 45 ° from the short direction 102, the energy density can be effectively improved by rolling and press-fitting without causing the strand 203 to break. It became clear that it was possible. Therefore, it is preferable to press-fit the mixture into the mesh from the direction exceeding 0 ° and 45 ° or less with respect to the short direction 102, or rolling the electrode precursor.

  The material of the expanded metal 100 is not particularly limited as long as it is a material that is chemically stable in a potential range used as a lithium secondary battery and has good electrical conductivity. For example, the current collector 1A of the positive electrode 1 can be made of aluminum, an alloy mainly containing aluminum, stainless steel, titanium, or the like. For the current collector 11 of the negative electrode 2, nickel or an alloy mainly containing nickel, copper, an alloy mainly containing copper, or stainless steel can be used. More preferably, aluminum or a metal mainly composed of copper is preferable from the viewpoint of the elongation rate until cutting occurs. Among them, aluminum is more preferable as a material for the current collector 1A because it forms a film on the surface and has a withstand voltage of 4.5 V based on the oxidation-reduction potential of lithium.

  In addition, it is preferable that the contact resistance between the active material and the expanded metal 100 is reduced by being pressed into contact with the surface of the expanded metal 100 without being deformed during pressure molding. From such a viewpoint, it is preferable to use an oxide having high mechanical strength as the active material.

  The method of press-fitting and rolling is not limited as long as the positive electrode layer 1B and the negative electrode layer 15 can be pressure-molded. However, plane pressurization tends to cause elongation other than in the pressurizing direction, and the effect of the present invention is reduced. For this reason, it is preferable to perform press-fitting and rolling with a roller having a pressurizing function capable of preferentially causing elongation in the intended direction. At this time, it is more preferable to have a mechanism for generating tension in the length direction so as to preferentially extend in the length direction.

  Hereinafter, an example of the press-fitting and rolling method using a roller will be described with reference to FIGS. FIG. 4 is a schematic side view showing a configuration of an apparatus for press-fitting a mixture containing an active material into an electrode current collector in an embodiment of the present invention, and FIG. 5 is a schematic top view showing a main part of the apparatus shown in FIG. It is. FIG. 6 is a schematic side view showing the configuration of the apparatus for rolling the electrode precursor in the embodiment of the present invention, and FIG. 7 is a schematic top view showing the main part of the apparatus shown in FIG.

  First, the press-fitting device will be described. As shown in FIG. 4, the press-fitting device includes an unwinding reel 51, forming rollers 52 and 53, and a press-fitting roller 54. A hoop of expanded metal 100 is wound around the unwinding reel 51. A mixture 55 containing an active material is supplied to the gap between the forming rollers 52 and 53 and above the gap. The expanded metal 100 is supplied from the unwinding reel 51 between the forming roller 53 and the press-fitting roller 54.

  When the forming roller 53 is rotated in this state, the mixture 55 is formed as a sheet 56 and is sent along the forming roller 53 to the gap with the press-fitting roller 54. When the press-fitting roller 54 is rotated in the opposite direction with respect to the forming roller 53, the sheet 56 is press-fitted into the expanded metal 100 sent from the unwinding reel 51. At this time, as shown in FIG. 5, the press-fitting direction 103 is within 45 ° with respect to the short direction 102 of the expanded metal 100. More preferably, it exceeds 0 °.

  In the apparatus shown in FIG. 4, the sheet 56 is once formed and then press-fitted into the expanded metal 100, but the present invention is not limited to this. For example, the expanded metal 100 may be supplied together with the mixture 55 to the gap between the forming roller 52 and the forming roller 53 by controlling the supply amount of the mixture 55 per unit time. In this way, the mixture 55 can be pressed into the expanded metal 100.

  Next, the rolling device will be described. As shown in FIG. 6, the rolling apparatus has a take-up reel 61 and rolling rollers 62 and 63. The unwinding reel 61 is wound with a hoop of an electrode precursor 80 in which a mixture containing an active material is press-fitted into the expanded metal 100 in advance. At this time, the filling method and the press-fitting degree of the mixture are not particularly limited. The expanded metal 100 may be press-fitted to some extent with the apparatus shown in FIGS. 4 and 5. Alternatively, the mixture may be prepared in the form of a paste, and the expanded metal 100 may be dipped or coated, filled, and dried to be used as the electrode precursor 80.

  The electrode precursor 80 is supplied between the rolling rollers 62 and 63. In this state, when the rolling rollers 62 and 63 are rotated in opposite directions, the electrode precursor 80 is rolled. At this time, as shown in FIG. 7, the rolling direction 103 is within 45 ° with respect to the short direction 102 of the expanded metal 100. More preferably, it exceeds 0 °.

  In the above description, the case where the expanded metal 100 is used for the current collectors 1A and 11 for both the positive electrode 1 and the negative electrode 2 has been described. However, the present invention is not limited to this. Only one of the positive electrode 1 and the negative electrode 2 may have such a structure.

  Moreover, the case where the rhombus opening 200 was provided as the expanded metal 100 was demonstrated. In addition to this, an expanded metal provided with a turtle shell-shaped opening in which the bond 206 is long along the long direction 101 may be used for at least one of the current collectors 1 </ b> A and 11. However, the expanded metal provided with the turtle shell-shaped opening has a smaller allowable range of elongation. Therefore, it is preferable to use the expanded metal 100 provided with the diamond-shaped opening 200 as shown in FIGS.

  In order to change the angle of the short direction 102 with respect to the longitudinal direction of the hoop of the expanded metal 100, for example, a method disclosed in International Publication No. 94/15375 can be applied. That is, a metal sheet material is used as the material of the expanded metal 100. And opening 200 is formed using the die set comprised by the die provided inclining with respect to the feed direction of a sheet material, and the cutter which meshes with this die.

  Moreover, although the cylindrical lithium secondary battery was demonstrated to the example as a battery, it cannot be overemphasized that it is not restricted to this. The present invention may be applied to a prismatic battery. In that case, the battery may be applied to a wound battery or a stacked battery.

(Example)
Hereafter, the effect of this Embodiment is demonstrated using the example in rolling. The mixture containing the active material was prepared by the following procedure. 90 g of Li ₄ Ti ₅ O ₁₂ powder (manufactured by Titanium Industry), 10 g of acetylene black, 5.2 g of polytetrafluoroethylene (manufactured by Daikin Industries) and 10 g of water are mixed in a kneading machine (a kneading machine made by Tokushu Kika Kogyo Co., Ltd., HiVISMIX). For 60 minutes to prepare a mixture containing a pasty active material.

  The expanded metal 100 used as the current collector 1A of the positive electrode 1 is made of aluminum. The thickness 204 shown in FIG. 3 is 0.1 mm, the width 205 of the strand 203 is 0.2 mm, the center distance 201 in the long direction is 3.0 mm, and the center distance 202 in the short direction is 1.1 mm.

  Next, the expanded metal 100 was placed on a polyethylene terephthalate (PET) film, and the mixture 55 was applied using an aluminum squeegee to produce an electrode precursor 80 of the positive electrode 1.

  Next, the electrode precursor 80 was dried together with the PET film under reduced pressure at 160 ° C. for 12 hours, and then the PET film was peeled off from the electrode precursor 80. The thickness of the electrode precursor 80 at this time was 900 μm, and the porosity calculated from the volume and weight and the true density of each material was approximately 60%.

  The produced electrode precursor 80 has a direction along the short direction 102 (0 ° direction), an angle direction of 5 °, 15 °, 30 °, 45 °, 60 ° with respect to the short direction 102, and a long length. Two sheets were cut out in a direction along the direction 101 (90 ° direction) so as to have a length of 10 cm and a width of 5 cm.

  The cut electrode precursor 80 was rolled five times at a roller gap of 500 μm and 300 μm with a roll press machine (manufactured by Sunk Metal, hydraulic pressurizing force 3 tons, roller rotation speed 3 rpm). Among positive electrodes rolled with a gap of 500 μm, samples of 0 ° direction, 5 ° direction, 15 ° direction, 30 ° direction, 45 ° direction, 60 ° direction, and 90 ° direction were respectively sample A, B, C, D, Samples of 0 ° direction, 5 ° direction, 15 ° direction, 30 ° direction, 45 ° direction, 60 ° direction, and 90 ° direction among the positive electrodes rolled with a gap of 300 μm as E, F, and G are each sample H , I, J, K, L, M, N. Table 1 shows the rolling conditions of each sample and whether or not the expanded metal 100 is broken.

  The thickness of the positive electrode after rolling was approximately the same as the roll gap, although there was some variation. Sample A to Sample G after rolling with a roll gap of 500 μm produced an elongation of about 4% in the length direction, and almost no elongation in the width direction was observed. When the porosity is calculated from the weight, thickness, and true density and elongation of each material, it is about 40%.

  On the other hand, Sample H to Sample L after rolling with a roll gap of 300 μm produced about 25% elongation in the length direction and about 3% in the width direction. When the porosity is calculated from the weight, thickness, and true density and elongation of each material, it is about 20%.

  In the case of Sample N (90 ° direction), the positive electrode breakage was clearly observed after the roll press, and hence the elongation and porosity could not be calculated. In order to observe whether or not the expanded metal 100 was cut in other samples, the positive electrode layer 1B was removed as follows. First, the positive electrodes of Sample A to Sample M were cut into a square with a side of 2 cm and immersed in N-methyl-2-pyrrolidone (NMP) for 12 hours. Thereafter, by applying ultrasonic waves, the positive electrode layer 1B was removed without damaging the expanded metal 100.

  As a result, in Sample A to Sample L, no breakage of expanded metal 100 could be confirmed, but in Sample M, breakage was observed at several locations.

  Samples A to G have a low compressibility, and the porosity is about 40% as described above. For this reason, the expanded metal 100 did not stretch greatly and did not break. In particular, when the samples F and G are compared with the samples M and N, the influence on the expansion of the expanded metal 100 due to the difference in the compressibility is remarkable. In order to increase the volume energy density as an electrode, it is necessary to increase the compressibility. Further, in the case of lithium using a nonaqueous electrolyte, it is necessary to increase the compressibility in order to reduce the resistance in the electrode. Therefore, in this Embodiment, it rolls from the direction within 45 degrees with respect to the short direction 102, and raises the compression rate of the positive electrode layer 1B. In that case, a high energy density is securable by making the porosity of an electrode layer less than 40%.

  Although not shown in the data, rolling was performed using the same material as Sample A to Sample E with a roller gap of 250 μm, and in any sample, there was a case where the cut of the positive electrode was observed after roll pressing. Furthermore, the sheet was rolled with an aluminum expanded metal having a thickness 204 of 0.03 mm to 0.1 mm and a width 203 of the strand 203 of 0.13 mm to 0.22 mm, with a roller gap of 250 μm as described above. In all samples, the positive electrode was observed to be cut after the roll press. Therefore, when producing a positive electrode using an aluminum expanded metal, it is preferable to keep the porosity of an electrode layer up to 20%.

  As described above, the porosity of the electrode layer is 20% or more and less than 40%. At this time, the expanded metal 100 extends from 4% to 25%.

  According to the manufacturing method of the present invention, the volume energy density is not reduced by the additional base material, and an electrode for a lithium secondary battery that exhibits only the effect of increasing the volume energy density by pressure molding can be produced. . Therefore, the volume energy density of the lithium secondary battery using the electrode manufactured by this method can be increased. Therefore, it is useful industrially.

DESCRIPTION OF SYMBOLS 1 Positive electrode 1A, 11 Current collector 1B Positive electrode layer 2 Negative electrode 3 Separator 4 Electrode group 5 Case 6 Sealing plate 7 Gasket 8 Positive electrode lead 9 Negative electrode lead 10A, 10B Insulating plate 15 Negative electrode layer 16 Positive electrode cap 18 PTC element 19 Current interruption member 30 Battery 51, 61 Unwinding reel 52, 53 Forming roller 54 Press-in roller 55 Mixture 56 Sheet 62, 63 Rolling roller 80 Electrode precursor 100 Expand metal 101 Long direction 102 Short direction 103 Direction 200 Opening 201 Center of long direction Distance 202 Distance between centers in the short direction 203 Strand 204 Plate thickness 205 Width 206 Bond

Claims (10)

Preparing a mixture comprising an active material;
An expanded metal having a mesh width in the long direction and a mesh width in the short direction is used as a current collector, and the mixture prepared from a direction within 45 ° with respect to the short direction of the current collector is the current collector And a step of press-fitting into the mesh opening. 2. The method for producing an electrode for a lithium secondary battery according to claim 1, wherein the mixture is press-fitted into the mesh from a direction of more than 0 ° and not more than 45 ° with respect to the short direction of the current collector. 2. The method for producing an electrode for a lithium secondary battery according to claim 1, wherein the active material is a positive electrode active material, and a material of the current collector is a metal mainly composed of aluminum. The active material is represented by a chemical formula of a compound having a layered structure represented by a chemical formula of LiMO ₂ (M: transition metal) or LiM ₂ O ₄ (M: a transition metal or a part of the transition metal is substituted by Li). The method for producing an electrode for a lithium secondary battery according to claim 1, wherein the compound has a spinel structure. Forming an electrode precursor by filling an expanded metal having a mesh width in the long direction and a mesh width in the short direction as a current collector, and filling the mixture of the current material into the mesh of the current collector; ,
Rolling the electrode precursor formed from a direction within 45 ° with respect to the short direction of the current collector, and a method for producing an electrode for a lithium secondary battery. 6. The method for producing an electrode for a lithium secondary battery according to claim 5, wherein the electrode precursor is rolled from a direction exceeding 0 ° and not more than 45 ° with respect to the short direction of the current collector. 6. The method for producing an electrode for a lithium secondary battery according to claim 5, wherein the active material is a positive electrode active material, and the material of the current collector is a metal mainly composed of aluminum. The active material is represented by a chemical formula of a compound having a layered structure represented by a chemical formula of LiMO ₂ (M: transition metal) or LiM ₂ O ₄ (M: a transition metal or a part of the transition metal is substituted by Li). 6. The method for producing an electrode for a lithium secondary battery according to claim 5, wherein the compound has a spinel structure. Forming an electrode group by opposing a first electrode and a second electrode having a polarity different from that of the first electrode;
Including a non-aqueous electrolyte in the electrode group, and
Each of the first electrode and the second electrode includes an active material capable of electrochemically inserting and removing lithium,
At least one of the first electrode and the second electrode is:
Preparing a mixture comprising an active material;
An expanded metal having a different mesh width in the long direction and a short mesh direction is used as a current collector, and the mixture prepared from a direction within 45 ° with respect to the short direction of the current collector is the current collector A method of manufacturing a lithium secondary battery, comprising: press-fitting into the mesh. Forming an electrode group by opposing a first electrode and a second electrode having a polarity different from that of the first electrode;
Including a non-aqueous electrolyte in the electrode group, and
Each of the first electrode and the second electrode includes an active material capable of electrochemically inserting and removing lithium,
At least one of the first electrode and the second electrode is:
Forming an electrode precursor by filling an expanded metal having a different mesh width in the long direction and a mesh width in the short direction as a current collector, and filling the mesh of the current collector with a mixture containing the active material; ,
Rolling the electrode precursor formed from a direction within 45 ° with respect to the short direction of the current collector. A method for producing a lithium secondary battery, comprising:

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