JP2012174414A - Nonaqueous electrolyte battery and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-capacity nonaqueous electrolyte battery having excellent productivity and also to provide a method of manufacturing the nonaqueous electrolyte battery.SOLUTION: In one embodiment, the nonaqueous electrolyte battery 1 is provided which includes a positive electrode 11, a negative electrode 12, a separator 13 and a nonaqueous electrolyte. The positive electrode 11 includes a positive electrode current collector 11a and an active material layer 11b formed on the positive electrode current collector 11a. The negative electrode 12 includes a negative electrode current collector 12a and an active material layer 12b formed on the negative electrode current collector 12a. The active material layer of at least one of the positive electrode 11 and the negative electrode 12 has a roughened surface. On the roughened surface, the maximum height of a convex part from the average height of a concave part and the convex part is in a range of 5% or more and 30% or less of the average thickness of the active material layer having the roughened surface.

Description

  Embodiments described herein relate generally to a nonaqueous electrolyte battery and a method for manufacturing the same.

  In order to increase the capacity of the nonaqueous electrolyte secondary battery, it is necessary to increase the amount of the active material. Attempts have been made to compress the electrodes in order to increase the amount of active material while maintaining predetermined battery dimensions. By compressing the electrode, the density of the active material layer is increased, whereby the amount of the active material can be increased. However, as the density of the active material layer increases, the voids in the active material layer decrease. Therefore, there is a problem that the electrolytic solution is not easily absorbed by the active material layer, and the productivity of the battery is reduced.

JP 2001-93520 A JP 11-167922 A Japanese Patent Laid-Open No. 9-22699

  An object of the present invention is to provide a high-capacity nonaqueous electrolyte battery excellent in productivity and a method for producing the same.

  According to the embodiment, a nonaqueous electrolyte battery including a positive electrode, a negative electrode, a separator, and a nonaqueous electrolyte is provided. The positive electrode includes a positive electrode current collector and an active material layer formed on the positive electrode current collector. The negative electrode includes a negative electrode current collector and an active material layer formed on the negative electrode current collector. The active material layer of at least one of the positive electrode and the negative electrode has a roughened surface. In the roughened surface, the maximum height of the convex portion from the average height of the concave and convex portions is 5% or more and 30% or less of the average thickness of the active material layer having the roughened surface. Is within the range.

The perspective view which shows the external appearance of the nonaqueous electrolyte battery of embodiment. The expansion | deployment perspective view of the battery of FIG. The expansion | deployment perspective view of the electrode group with which the battery of FIG. 1 is equipped. The enlarged schematic diagram of the surface of the roughened active material layer. The schematic diagram of the brush cleaner used for surface treatment.

  Each embodiment will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is an external view of a square nonaqueous electrolyte battery 1. FIG. 2 is a developed perspective view of the nonaqueous electrolyte battery 1 of FIG. As shown in FIG. 2, the nonaqueous electrolyte battery 1 includes a flat electrode group 2.

  The electrode group 2 is accommodated in the outer can 3. A lid 4 is attached to the opening of the outer can 3, thereby sealing the outer can 3. The lid 4 includes a positive electrode terminal 5 and a negative electrode terminal 6. The positive electrode terminal 5 is attached to the lid 4 via an insulating gasket 9 by, for example, caulking. The negative electrode terminal 6 is attached to the lid 4 via an insulating gasket 10 by, for example, caulking.

  Inside the outer can 3, a positive electrode lead 7 and a negative electrode lead 8 are provided. Each of the positive electrode lead 7 and the negative electrode lead 8 includes a connection plate having a through-hole, and a strip-shaped current collecting portion that branches off from the connection plate and extends downward. The positive electrode lead 7 is fixed to the lid 4 by fixing the positive electrode terminal 5 to the through hole thereof by caulking. Thereby, the positive electrode terminal 5 and the positive electrode lead 7 are electrically connected. The negative electrode lead 8 is fixed to the lid 4 by caulking and fixing the negative electrode terminal 6 to the through hole. Thereby, the negative electrode terminal 6 and the negative electrode lead 8 are electrically connected.

  FIG. 3 is a developed perspective view of the electrode group 2. The electrode group 2 has a configuration in which a positive electrode 11 and a negative electrode 12 are stacked via a separator 13 and wound into a flat shape.

  The positive electrode 11 includes a positive electrode current collector 11a and a positive electrode active material layer 11b. The positive electrode active material layer 11b is formed on one side or both sides of the positive electrode current collector 11a. The positive electrode active material layer 11 b is formed leaving an end parallel to the longitudinal direction of the positive electrode 11. Thereby, the non-coating part which the positive electrode electrical power collector 11a exposed is left in the edge part parallel to the longitudinal direction of a positive electrode. This non-coated part is used as the positive electrode current collecting tab 11c. The positive electrode current collecting tab 11c may be formed at both ends of the positive electrode, but is preferably formed only at one end.

  The negative electrode 12 includes a negative electrode current collector 12a and a negative electrode active material layer 12b. The negative electrode active material layer 12b is formed on one side or both sides of the negative electrode current collector 12a. The negative electrode active material layer 12 b is formed leaving an end parallel to the longitudinal direction of the negative electrode 12. Thereby, the non-coating part which the negative electrode collector 12a exposed is left in the edge part parallel to the longitudinal direction of a negative electrode. This non-coated portion is used as the negative electrode current collecting tab 12c. The negative electrode current collecting tab 12c may be formed at both ends of the negative electrode, but is preferably formed only at one end.

  The positive electrode 11 and the negative electrode 12 are arranged such that the positive electrode current collecting tab 11c protrudes from the separator 13 in the winding axis direction of the electrode group, and the negative electrode current collecting tab 12c protrudes from the separator 13 in the opposite direction. The 12 positions are overlapped and wound. Thereby, as shown in FIG. 2, the electrode group 2 has a positive current collecting tab 11c wound spirally from one end face and a negative current collecting tab wound spirally from the other end face. 12c protrudes. The electrode group 2 is covered with an insulating tape 14 as shown in FIG. 2 in order to wind the electrode group 2 and insulate the electrode group 2 and the outer can 3 from each other.

  As shown in FIG. 2, the positive electrode current collecting tab 11 c is joined to the positive electrode lead 7. Thereby, the positive electrode 11, the positive electrode lead 7, and the positive electrode terminal 5 are electrically connected. Similarly, the negative electrode current collecting tab 12 c is joined to the negative electrode lead 8. Thereby, the negative electrode 12, the negative electrode lead 8, and the negative electrode terminal 6 are electrically connected. The joining of the positive and negative current collecting tabs 11c and 12c and the positive and negative electrode leads 7 and 8 can be performed by, for example, ultrasonic welding.

  The electrode group 2 in which the positive and negative electrode leads 7 and 8 and the positive and negative electrode current collecting tabs 11 c and 12 c are joined, and the electrolytic solution are accommodated in the outer can 3. The lid 4 is sealed by being joined to the opening of the outer can 3. The joining can be performed, for example, by seam welding using a laser.

  The outer can 3 and the lid 4 may be formed of a metal such as aluminum, aluminum alloy, iron, and stainless steel, respectively. The outer can 3 and the lid 4 may be formed of different types of metal, but are preferably formed of the same type of metal.

  The positive electrode current collector 11a is preferably formed from an aluminum foil or an aluminum alloy foil containing one or more elements selected from the group consisting of Mg, Ti, Zn, Mn, Fe, Cu, and Si. The negative electrode current collector 12a is preferably formed from an aluminum foil, an aluminum alloy foil containing one or more elements selected from the group consisting of Mg, Ti, Zn, Mn, Fe, Cu and Si, or a copper foil. .

  In the present embodiment, at least one of the positive electrode active material layer 11b and the negative electrode active material layer 12b has a roughened surface. In the roughened surface, the maximum height of the convex portion from the average height of the concave and convex portions is in the range of 5 to 30% of the average thickness of the active material layer having the roughened surface. Is within.

  FIG. 4 is an enlarged schematic view of the cross section of the roughened surface. As shown in FIG. 4, a plurality of minute grooves are formed on the roughened surface. This groove is composed of a mountain-shaped convex portion and a valley-shaped concave portion, and a portion higher than the reference surface 16 is referred to as a convex portion, and a lower portion is referred to as a concave portion. The reference surface 16 is the average height of the convex portions and the concave portions, and is determined so that the total area of the convex portions and the total area of the concave portions are equal. The length from the reference surface 16 to the apex of the convex portion is referred to as the height of the convex portion, and the height 17 of the highest convex portion is the maximum height (Rp) of the convex portion.

  In the present embodiment, the roughened surface has a maximum height (Rp) of the convex portion within the range of 5% to 30% of the average thickness of the active material layer having the roughened surface. It is.

  According to this embodiment, the surface of the active material layer is roughened to form a plurality of grooves, whereby the liquid absorbability of the electrolytic solution can be improved. Therefore, mass productivity can be improved in battery manufacture.

  The surface roughness increases as the maximum height (Rp) of the convex portion increases. By making the maximum height (Rp) of the convex part 5% or more of the average thickness of the active material layer, the effect of improving the liquid absorbency can be obtained. On the other hand, by setting the maximum height (Rp) of the convex portion to 30% or less of the average thickness of the active material layer, it is possible to reduce the risk of an internal short circuit penetrating the separator.

  The plurality of grooves formed on the roughened surface of the active material layer are not limited to this, but are formed in the same direction on the surface of the active material. In addition, the plurality of grooves are preferably on the entire surface of the active material.

  Note that since the active material layer is formed on the current collector, the roughened surface is a surface positioned opposite to the current collector side.

  Furthermore, it is preferable that the maximum height of the convex portion is 50% or less of the average thickness of the separator. By being 50% or less of the average thickness of the separator, even if the positions of the highest convex portions on the surface of the positive electrode active material layer and the surface of the negative electrode active material layer coincide, the convex portion penetrates the separator and is internally short-circuited. Can be prevented.

  Furthermore, the current collector on which the active material layer having a roughened surface is formed preferably has a thickness in the range of 10 μm to 30 μm. By making the thickness 10 μm or more, the current collector can be prevented from being broken. Moreover, the energy density of a battery can be improved by making thickness into 30 micrometers or less.

  The positive electrode active material layer 11b contains a positive electrode active material. As the positive electrode active material, oxides, sulfides, and polymers that can occlude and release lithium can be used. Active materials such as lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, and lithium iron phosphate are more preferable because a high positive electrode potential can be obtained.

The negative electrode active material layer 12b contains a negative electrode active material. As the negative electrode active material, metal oxides, metal sulfides, metal nitrides, and alloys that can occlude and release lithium can be used. An oxide having a lithium ion storage / release potential of no less than 0.4 V relative to the lithium metal potential is preferably used. When an oxide having such a lithium ion storage / release potential is used, an alloy reaction between aluminum or an aluminum alloy and lithium can be suppressed. Therefore, the negative electrode current collector and the member related to the negative electrode can be formed of aluminum or an aluminum alloy. Examples of such oxides include lithium titanium composite oxides such as titanium oxide and lithium titanate, tungsten oxide, amorphous tin oxide, tin silicon oxide, and silicon oxide. In particular, lithium titanium composite oxide is preferable. Note that the upper limit of the lithium ion storage potential of an oxide having a lithium ion storage potential of 0.4 V (vs. Li / Li ⁺ ) or more is not limited to this, but is preferably 2 V.

  Separator 13 may be a microporous membrane, woven or non-woven fabric, or a combination thereof. The separator 13 may be formed of a material selected from the group consisting of polyethylene, polypropylene, ethylene-propylene copolymer, and ethylene-butene copolymer.

  The electrolytic solution may be a non-aqueous electrolytic solution prepared by dissolving an electrolyte (for example, a lithium salt) in a non-aqueous solvent.

Examples of the non-aqueous solvent include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), γ-butyrolactone (γ -BL), sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran and the like. These solvents may be used alone or as a mixture of two or more solvents.
Examples of electrolytes include lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), trifluorometa Examples thereof include lithium salts such as lithium sulfonate (LiCF ₃ SO ₃ ). The electrolyte may be used alone or in combination of two or more. The amount of electrolyte dissolved in the non-aqueous solvent is preferably in the range of 0.2 mol / L to 3 mol / L.

  According to the present embodiment described above, it is possible to improve the liquid absorption of the active material layer even in a battery with a high capacity, and to provide a high capacity non-aqueous electrolyte battery with excellent productivity. it can.

(Second Embodiment)
Next, a method for manufacturing the nonaqueous electrolyte battery according to the first embodiment will be described. The manufacturing method includes forming an active material layer on a positive electrode current collector to produce a positive electrode, forming an active material layer on a negative electrode current collector to produce a negative electrode, and forming the positive electrode and the negative electrode The surface of the active material layer of at least one electrode is brushed with a fiber bundle to roughen the surface, and the positive electrode and the negative electrode are laminated via a separator to produce an electrode group. Including. Here, in the roughening, the maximum height (Rp) of the convex part from the average height of the concave part and the convex part is 5% or more and 30% or less of the average thickness of the roughened active material layer. Done to be within range.

  At least one of the positive electrode and the negative electrode constituting the electrode group may be processed according to this embodiment, but both electrodes are preferably processed according to this embodiment.

  First, a positive electrode manufacturing slurry and a negative electrode manufacturing slurry are prepared. The slurry is prepared by suspending an active material for a positive electrode or a negative electrode, a conductive agent, and a binder in a solvent.

  Examples of the positive electrode active material and the negative electrode active material are as described in the first embodiment.

  The conductive agent is used to suppress contact resistance between the active material and the current collector. As the conductive agent, for example, a carbonaceous material such as acetylene black, carbon black, and graphite can be used.

  The binder is used to bind the active material and the conductive agent. For example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), and fluorine-based rubber can be used as the binder.

  The compounding ratio of the positive electrode active material, the conductive agent, and the binder in the positive electrode manufacturing slurry is 80 wt% to 95 wt% for the positive electrode active material, 3 wt% to 18 wt% for the conductive agent, and the binder is It is preferable to be in the range of 2 wt% or more and 17 wt% or less. When the conductive agent is contained in an amount of 3% by weight or more, the above-described effects can be obtained. By including the conductive agent in a range of 18% by weight or less, the decomposition of the nonaqueous electrolyte on the surface of the conductive agent under high temperature storage can be reduced. it can. When the binder is contained in an amount of 2% by weight or more, sufficient electrode strength can be obtained, and when it is contained in the range of 17% by weight or less, the amount of the insulator can be reduced and the internal resistance can be reduced.

  The mixing ratio of the negative electrode active material, the conductive agent and the binder in the slurry for producing the negative electrode is such that the negative electrode active material is 70% by weight to 96% by weight, the conductive agent is 2% by weight to 28% by weight, and the binder is It is preferable to be in the range of 2 wt% or more and 28 wt% or less. By containing 2% by weight or more of the conductive agent, the current collecting performance of the negative electrode layer can be improved, and the large current characteristics of the battery can be improved. In addition, when the binder is contained in an amount of 2% by weight or more, the binding property between the negative electrode layer and the negative electrode current collector can be improved, and the cycle characteristics can be improved. On the other hand, from the viewpoint of increasing the capacity, it is preferable that the conductive agent and the binder are included in a range of 28% by weight or less.

  For example, N-methylethylpyrrolidone can be used as a solvent for preparing the slurry. The mixing ratio of the total weight of the active material, conductive agent and binder to the weight of the solvent is preferably in the range of 50:50 to 80:20.

  Next, the positive electrode manufacturing slurry is applied onto the positive electrode current collector and dried to form a positive electrode active material layer. Moreover, the slurry for negative electrode manufacture is apply | coated on a negative electrode electrical power collector, and it dries, and forms a negative electrode active material layer. In each of the positive and negative electrodes, the active material layer may be formed only on one side or both sides of the current collector. The slurry is applied leaving a portion corresponding to the end parallel to the longitudinal direction of the electrode. Thereby, the non-coating part which the electrical power collector exposed is obtained. This non-coated part is used as a current collecting tab. The non-coated portion may be formed at both ends of the electrode, but is preferably formed only at one end. Next, if necessary, the electrode is cut into a strip shape.

  Next, the strip-shaped electrode is subjected to a rolling process to compress the active material layer. The rolling process can be performed, for example, by loading the electrode with a roller using a roller press device.

  Next, in at least one of the positive electrode and the negative electrode, the surface of the active material layer is brushed with a fiber bundle to roughen the surface. By brushing with a fiber bundle, the surface of the active material layer can be slightly scraped to form a plurality of minute grooves.

  The brushing can be performed using, for example, a brush cleaner as shown in FIG. The brush cleaner 18 illustrated in FIG. 5 includes a brush 19, an exterior 20 that surrounds the brush, and a suction device 21. The brush 19 has a configuration in which the fiber bundle 23 is fixed to the rotating shaft 22. The suction device 21 is provided above the brush 19.

  The brush cleaner 18 is disposed so that the tip of the fiber bundle 23 is in contact with the surface of the active material layer of the electrode 24. For example, the surface of the active material layer can be brushed by moving the electrode 24 in a certain direction and rotating the brush 19 in a direction opposite to the moving direction of the electrode 24 while fixing the brush cleaner 18. The active material scraped from the surface of the active material layer by brushing is sucked by the suction device 21.

  By brushing the surface of the active material layer using such a brush cleaner 18, a plurality of minute grooves in a certain direction are formed on the surface of the active material layer, and the surface can be roughened.

  The brush cleaner 18 is not limited to this, but preferably has a width comparable to the width of the electrode 24 to be processed.

  In the roughening, the maximum height (Rp) of the convex portion from the average height of the concave and convex portions is in the range of 5% to 30% of the average thickness of the roughened active material layer. To be done. For example, by adjusting the contact strength between the fiber bundle 23 and the active material layer surface, the material of the fibers of the fiber bundle 23, the average diameter of the fibers, the rotation speed of the brush 19, and the like, the maximum height (Rp) of the convex portion is set. Can be adjusted.

  Further, the roughening is preferably performed so that the maximum height of the convex portion is 50% or less of the average thickness of the separator. When the maximum height of the convex portion is 50% or less of the average thickness of the separator, the convex portion can be formed even if the positions of the highest convex portions of the positive electrode active material layer surface and the negative electrode active material layer surface are the same. It is possible to prevent an internal short circuit from being caused through the separator.

  Further, the fibers of the fiber bundle 23 are formed of a flexible material that is excellent in impact resistance and wear resistance and does not apply an unnecessary load to the electrode because the fibers come into contact with the active material layer to roughen the surface. Of these, nylon resin fibers are preferably used. In particular, fibers made of nylon resin such as 6,6-nylon, 6-nylon, and 612-nylon are preferably used.

  Moreover, it is preferable that the average diameter of a fiber exists in the range of 0.1 mm-0.3 mm. When the average diameter is 0.1 mm or more and 0.3 mm or less, a groove having an appropriate width can be formed on the surface of the active material.

  In addition, the roughening of the surface of the active material layer according to the present embodiment can achieve a greater effect by being performed on the active material layer whose surface is smoothed by a rolling process.

  Next, the roughened belt-like electrode is laminated with a counter electrode through a separator to manufacture an electrode group. That is, when the roughened strip-shaped electrode is a positive electrode, it is laminated with the negative electrode, and when the roughened strip-shaped electrode is a negative electrode, it is laminated with the positive electrode. Note that, as described above, both the positive electrode and the negative electrode are preferably subjected to a roughening treatment.

  A wound electrode group can be manufactured by laminating and winding a belt-like positive electrode and a negative electrode with a separator interposed therebetween. Or a laminated electrode can be manufactured by cut | disconnecting a strip | belt-shaped positive electrode and a negative electrode to a desired magnitude | size, and piled up in a stack form on both sides of a separator.

  The electrode group 2 produced as described above is accommodated in the outer can 3, and the lid 4 is joined to the opening of the outer can 3. The joining can be performed, for example, by seam welding using a laser. Next, the electrolytic solution is injected into the outer can 3 from the injection port 15 provided in the lid 4 and then sealed.

  According to the above method, the liquid absorbency of the electrolytic solution is improved, and a high-capacity nonaqueous electrolyte battery can be manufactured with high productivity.

  In the above description, a battery using a non-aqueous electrolyte is used as an example, but this embodiment is also applied to a battery using a solid electrolyte or a polymer electrolyte instead of the non-aqueous electrolyte.

  Hereinafter, embodiments of the present invention will be described in detail.

Example 1
A positive electrode slurry was prepared using lithium cobalt oxide as a positive electrode active material. This slurry was applied to both sides of an aluminum foil (thickness: 15 μm) and dried to produce a positive electrode.

  A slurry for preparing a negative electrode was prepared using lithium titanate as a negative electrode active material. This slurry was applied on both sides of an aluminum foil (thickness: 15 μm) and dried to prepare a negative electrode.

  Each of the produced positive electrode and negative electrode was cut with a slitter so that the overall width was 100 mm, the current collecting tab (non-coated portion) width was 10 mm, and the active material layer width was 90 mm, A positive electrode and a negative electrode were obtained.

  Next, the belt-like positive electrode and negative electrode were pressed to a predetermined density using a roller press.

  Next, each of the belt-like positive electrode and the negative electrode was brushed using a brush cleaner. The brush cleaner fibers were 6,6-nylon and had an average diameter of 0.2 mm.

  The maximum heights (Rp) of the convex portions on the surfaces of the positive electrode and negative electrode active material layers after brushing were 9.04 μm and 8.99 μm, respectively.

  The positive electrode and the negative electrode were stacked with a separator having a thickness of 20 μm interposed therebetween, and wound to produce a cylindrical electrode group. This was hot-pressed at about 80 ° C. and molded into a flat shape. Furthermore, it fixed with the insulating tape and produced the wound electrode group.

  Positive and negative electrode terminals and positive and negative electrode leads were fixed to the lid, respectively. The positive and negative electrode current collecting tabs of the wound electrode group were joined to the positive and negative electrode leads by laser welding. The wound electrode group fixed to the lid was housed in a metal outer can, and the lid and the outer can were joined by laser welding. A non-aqueous electrolyte solution was injected from the injection port, a sealing plug was inserted, and it was sealed by laser welding. As a result, a 20 Ah non-aqueous electrolyte secondary battery was produced.

(Example 2)
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the maximum height (Rp) of the convex portions on the surface of the active material layer of the positive electrode and the negative electrode was changed to the values shown in Table 1.

(Comparative example)
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the positive electrode and negative electrode active material layers were not subjected to the brushing treatment.

(Measurement of liquid absorption time)
In the step of injecting the non-aqueous electrolyte when manufacturing the battery, the liquid absorption time until the non-aqueous electrolyte completely penetrated was measured. The test was performed with 100 batteries for each of Examples 1 and 2 and the comparative example. Each battery was injected with 30 g of a non-aqueous electrolyte. The results are shown in Table 1.

(Insulation inspection)
In order to confirm the occurrence of an internal short circuit, an insulation test was performed after measuring the liquid absorption time. When the internal resistance was 10 kΩ or more, it was determined to be insulating, and when it did not exceed 10 kΩ, it was determined to be conductive. Table 1 shows the ratio of batteries determined to be conductive among the tested batteries as the conductivity.

(result)
As is clear from Table 1, the batteries of Examples 1 and 2 completed the liquid absorption in 3 to 4 hours. On the other hand, the battery of the comparative example required 13 hours to complete the liquid absorption. Therefore, it was shown that the battery in which the surface of the active material layer is roughened according to the present embodiment has a significantly reduced liquid absorption time.

  As a result of the insulation test, 9% of the batteries of Example 2 were conductive, but all of the batteries of Example 1 were insulated. Therefore, when the maximum height of the convex part on the surface of the active material layer is 50% or less of the average thickness of the separator, it was shown that the insulating property is high.

(Charge / discharge test)
A charge / discharge test was performed using the batteries of Examples 1 and 2 and the comparative example. Charging / discharging 1000 cycles was performed at 1 C, and the capacity retention rate after 1000 cycles was calculated. The results are shown in Table 2. Note that Example 2 was tested using a battery that was confirmed to be non-conductive in an insulation test.

  Both the batteries of Examples 1 and 2 exhibited almost the same capacity retention rate as the comparative example. Therefore, it was shown that even if the surface of the active material layer was brushed to form minute grooves, the cycle characteristics were not affected.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Nonaqueous electrolyte battery, 2 ... Electrode group, 3 ... Outer can, 4 ... Cover, 5 ... Positive electrode terminal, 6 ... Negative electrode terminal, 7 ... Positive electrode lead, 8 ... Negative electrode lead, 9, 10 ... Insulating gasket, 11 ... Positive electrode, 11a ... Positive electrode current collector, 11b ... Positive electrode active material layer, 11c ... Positive electrode current collector tab, 12 ... Negative electrode, 12a ... Negative electrode current collector, 12b ... Negative electrode active material layer, 12c ... Negative electrode current collector tab, 13 ... Separator, 14 ... insulating tape, 15 ... injection port, 16 ... reference surface, 17 ... maximum height of convex part, 18 ... brush cleaner, 19 ... brush, 22 ... rotating shaft, 23 ... fiber bundle.

Claims (8)

A positive electrode comprising a positive electrode current collector and an active material layer formed on the positive electrode current collector;
A negative electrode comprising a negative electrode current collector and an active material layer formed on the negative electrode current collector;
A separator;
A non-aqueous electrolyte,
Including
The active material layer of at least one of the positive electrode and the negative electrode has a roughened surface,
In the roughened surface, the maximum height of the convex portion from the average height of the concave and convex portions is 5% or more and 30% or less of the average thickness of the active material layer having the roughened surface. A nonaqueous electrolyte battery characterized by being in the range of   The non-aqueous electrolyte battery according to claim 1, wherein the maximum height of the convex portion is 50% or less of the average thickness of the separator.   The nonaqueous electrolyte battery according to claim 2, wherein the positive electrode current collector and the negative electrode current collector have a thickness in a range of 10 μm to 30 μm. The active material layer of the negative electrode contains a lithium titanium composite oxide having a lithium ion storage potential of 0.4 V (vs. Li / Li ⁺ ) or more as an active material. Non-aqueous electrolyte battery. Forming a positive electrode by forming an active material layer on a positive electrode current collector;
Forming an active material layer on a negative electrode current collector to produce a negative electrode;
Brushing the surface of the active material layer of at least one of the positive electrode and the negative electrode with a fiber bundle to roughen the surface;
Laminating the positive electrode and the negative electrode via a separator to produce an electrode group,
The roughening is such that the maximum height of the convex portion from the average height of the concave and convex portions is in the range of 5% to 30% of the average thickness of the roughened active material layer. A method for producing a non-aqueous electrolyte battery, which is performed.   The method for producing a nonaqueous electrolyte battery according to claim 5, wherein the roughening is performed so that a maximum height of the convex portion is 50% or less of an average thickness of the separator.   The manufacturing method according to claim 6, wherein the active material layer whose surface is roughened has been subjected to a rolling treatment.   The method according to claim 6 or 7, wherein the fibers of the fiber bundle are made of nylon resin, and the average diameter of the fibers is in the range of 0.1 mm to 0.3 mm.

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