JP2012181978A - Nonaqueous electrolyte battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery achieving high power generation efficiency while using an electrode comprising a thick electrode mixture layer.SOLUTION: The nonaqueous electrolyte battery is made by sealing an exterior body containing an electrode body in which a separator intervenes between a positive electrode and a negative electrode, and a nonaqueous electrolyte. The positive electrode and the negative electrode each comprise an electrode mixture layer containing an active material on one side or both sides of a collector, at least the electrode mixture layer on one side of at least one of the positive electrode and the negative electrode has a thickness of 100 μm or larger and comprises a plurality of grooves having an opening on the surface opposite to the collector, the grooves have a width L1 in the range of 100 to 800 μm, and the grooves adjacent to each other have a pitch L2 in the range of 2 to 5 mm.

Description

  The present invention relates to a non-aqueous electrolyte battery with high power generation efficiency. The present invention includes a non-aqueous electrolyte primary battery and a non-aqueous electrolyte secondary battery. In this specification, the non-aqueous electrolyte secondary battery, which is a particularly main form of the present invention, is mainly described. Explained.

  Non-aqueous electrolyte batteries, such as secondary batteries, that have been widely used for power supply applications such as portable electronic devices, have a positive electrode having a positive electrode mixture layer on one side or both sides of the current collector, A laminated electrode body in which a negative electrode having a negative electrode mixture layer on one side or both sides is overlapped via a separator, and a wound electrode body in which this is wound in a spiral shape together with a non-aqueous electrolyte In general, those having a structure enclosed in an outer package such as a battery can or a laminate film outer package are generally used.

  In the nonaqueous electrolyte battery, the electrode mixture layer such as the positive electrode mixture layer and the negative electrode mixture layer is usually about 100 μm in thickness, but for the purpose of increasing the capacity of the nonaqueous electrolyte battery, It has also been studied to form a non-aqueous electrolyte battery using an electrode having a thicker electrode mixture layer than before.

  At the time of manufacturing the nonaqueous electrolyte battery, for example, the nonaqueous electrolyte is injected into the exterior body in which the electrode body having the above-described form is loaded. At this time, the non-aqueous electrolyte soaks into the electrode mixture layer from the surface of the electrode mixture layer opposite to the current collector, but when the electrode mixture layer is relatively thin as in the prior art, the electrode As the non-aqueous electrolyte penetrates well throughout the thickness direction of the mixture layer, almost the entire active material (positive electrode active material or negative electrode active material) present in the electrode mixture layer can contribute to power generation. .

  However, when the electrode mixture layer is thickened to, for example, 100 μm or more, the thickness direction of the electrode mixture layer is increased even if the nonaqueous electrolyte soaks into the electrode mixture layer from the surface opposite to the current collector of the electrode mixture layer. There is a problem that the non-aqueous electrolyte does not spread over the entire surface, and, for example, an active material existing in a region close to the current collector cannot participate in power generation, and the capacity as expected cannot be extracted.

  On the other hand, there is also a proposal of a technique for improving the permeability of the nonaqueous electrolytic solution into the electrode mixture layer. For example, Patent Document 1 discloses non-aqueous electrolysis in an active material layer by forming a cross lattice-shaped groove having a specified width, pitch, and depth on the surface of an active material layer (electrode mixture layer). A non-aqueous electrolyte battery having an electrode with enhanced liquid permeability is shown.

JP 2007-31328 A

  According to the technique described in Patent Document 1, the permeability of the nonaqueous electrolytic solution into the electrode mixture layer can be improved satisfactorily. However, the demand for higher capacity in the current non-aqueous electrolyte battery is increasing more than ever, and when the electrode mixture layer is made thicker to meet this demand, it is described in Patent Document 1. It is also anticipated that this technique may not be able to cope with this, and in this respect, the technique described in Patent Document 1 still leaves room for improvement.

  This invention is made | formed in view of the said situation, The objective is to provide a nonaqueous electrolyte battery with high electric power generation efficiency, using the electrode with a thick electrode mixture layer.

  The non-aqueous electrolyte battery of the present invention that can achieve the above object is formed by sealing an electrode body formed with a separator interposed between a positive electrode and a negative electrode, and an exterior body that contains the non-aqueous electrolyte. The positive electrode and the negative electrode have an electrode mixture layer containing an active material on one side or both sides of a current collector, and at least one of the positive electrode and the negative electrode, The electrode mixture layer present on at least one surface has a thickness of 100 μm or more and has a plurality of grooves having openings on the surface opposite to the current collector, and the width L1 of the grooves is It is 100-800 micrometers, The pitch L2 of the said adjacent groove parts is 2-5 mm, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, a nonaqueous electrolyte battery with high electric power generation efficiency can be provided, using an electrode with a thick electrode mixture layer.

It is a perspective view showing typically an example of the electrode concerning the nonaqueous electrolyte battery of the present invention. FIG. 2 is a partially enlarged view illustrating an example of a cross section taken along line AA in FIG. 1. It is a partially expanded view showing the other example of the AA line cross section of FIG. FIG. 2 is a perspective view schematically illustrating an example of the other surface (back surface) of the electrode in FIG. 1. FIG. 5 is a partially enlarged view illustrating an example of a cross section taken along line AA in FIG. 4. It is a longitudinal cross-sectional view showing an example of the nonaqueous electrolyte battery of this invention to a schematic diagram.

  The nonaqueous electrolyte battery of the present invention includes a positive electrode having an electrode mixture layer (that is, a positive electrode mixture layer) containing an active material (positive electrode active material) on one side or both sides of a current collector, And a negative electrode having an electrode mixture layer (that is, a negative electrode mixture layer) containing an active material (negative electrode active material) or the like on one side or one side.

  When at least one of the negative electrode and the positive electrode according to the non-aqueous electrolyte battery of the present invention has an electrode mixture layer only on one side, the electrode mixture layer has electrode mixture layers on both sides. In this case, at least one of the electrode mixture layers has a plurality of grooves having a thickness of 100 μm or more and having openings at least on the surface opposite to the current collector.

  The schematic diagram showing an example of the electrode which concerns on the nonaqueous electrolyte battery of this invention which has the said several groove part in an electrode mixture layer in FIG. 1 and FIG. 2 is shown. FIG. 1 is a perspective view of the electrode 10, and FIG. 2 is a partially enlarged view of a cross section taken along the line AA of the electrode 10 of FIG. 1.

  The electrode 10 shown in FIGS. 1 and 2 has an electrode mixture layer (positive electrode mixture layer or negative electrode mixture) containing an active material (positive electrode active material or negative electrode active material), a conductive auxiliary agent, etc. on both surfaces of the current collector 30. Agent layers) 20 and 21, and the electrode mixture layers 20 and 21 are provided with groove portions 20 a and 21 a having openings on the surface opposite to the current collector 30.

  When manufacturing a nonaqueous electrolyte battery, when the nonaqueous electrolyte is injected into the exterior body in which the electrode body configured using the electrode 10 is loaded, the nonaqueous electrolyte becomes an electrode mixture layer of the electrode 10 through the grooves 20a and 21a. Good spread throughout 20 and 21. Therefore, since the thickness of the electrode mixture layers 20 and 21 is 100 μm or more, the active material present in the vicinity of the current collector, which is usually insufficient for non-aqueous electrolyte and hardly contributes to the battery reaction, It can be well involved in battery reactions. Therefore, the non-aqueous electrolyte battery of the present invention having such an electrode has high power generation efficiency.

  FIG. 3 is a partially enlarged view schematically showing another example of a cross section taken along line AA of the electrode 10 of FIG. FIG. 3 shows that the cross-sectional shape in the width direction of the groove portions 20a and 21b provided in the electrode mixture layers 20 and 21 of the electrode 10 is on the surface of the electrode mixture layers 20 and 21 opposite to the current collector 30. It is an example of a trapezoid whose width increases as it goes.

  The cross-sectional shape in the width direction of the groove is not particularly limited, and may be, for example, a rectangular shape (including a square shape) as shown in FIG. 2 or a trapezoidal shape as shown in FIG. Alternatively, it may be a triangular shape having a base on the current collector side surface of the electrode mixture layer, or a polygonal shape such as a pentagonal shape or a hexagonal shape having one side on the current collector side surface of the electrode mixture layer. Among these, the amount of active material in the vicinity of the current collector of the electrode mixture layer can be increased, and the permeability of the non-aqueous electrolyte can be enhanced by capillary action even at a location closer to the current collector. A trapezoidal shape as shown is more preferable.

  From the viewpoint of increasing the capacity of the battery, the electrode mixture layer having a groove has a thickness (if there is an electrode mixture layer on both sides of the current collector, the thickness per side. About the thickness of the electrode mixture layer The same shall apply hereinafter) is 100 μm or more, preferably 120 μm or more. However, if the electrode mixture layer is too thick, for example, the conductivity in the vicinity of the surface on the side opposite to the current collector is lowered, and the effect of increasing the capacity of the battery may be reduced. Therefore, the thickness of the electrode mixture layer having a groove is preferably 200 μm or less, and more preferably 180 μm or less.

  If the width L1 of the groove provided in the electrode mixture layer is too small, the non-aqueous electrolyte does not easily enter the groove due to its surface tension, and the above-described effect due to the provision of the groove is reduced. There is a fear. Therefore, from the viewpoint of avoiding such a problem and ensuring the above-described effect by providing the groove part satisfactorily, the width L1 of the groove part is 100 μm or more and preferably 200 μm or more.

  On the other hand, if the groove width L1 is too large, the amount of the active material in the electrode mixture layer is reduced and the capacity of the battery cannot be improved. Therefore, L1 is 800 μm or less and 500 μm or less. Is preferred.

  In addition, as shown in FIG.2 and FIG.3, the width L1 of the groove part by this invention means the width | variety of the opening part of the groove part in the surface on the opposite side to the electrical power collector of an electrode mixture layer. Then, the width L1 of the groove portion is divided into 10 equal lengths of the entire length of the groove portion to measure the width, and in each divided portion, the width at the central portion in the direction in which the groove portion extends is measured, and these average values are obtained. Desired.

  In addition, in the plurality of groove portions provided in the electrode mixture layer, if the pitch L2 between adjacent groove portions is too short, the number of groove portions to be formed increases, and the amount of active material in the electrode mixture layer decreases. In other words, the amount of the active material that falls off from the electrode mixture layer increases, and the amount of the active material that can contribute to the battery reaction decreases, so that the capacity of the battery cannot be improved. Therefore, from the viewpoint of avoiding such a problem and improving the capacity of the battery, the pitch L2 between adjacent grooves is 2 mm or more, and preferably 3 mm or more.

  On the other hand, if the pitch L2 between the adjacent groove portions is too long, the amount of the non-aqueous electrolyte that permeates into the vicinity of the current collector of the electrode mixture layer is reduced, and the above-described effect due to the provision of the groove portions is reduced. Therefore, the pitch L2 between adjacent groove portions is 5 mm or less, and preferably 4.5 mm or less.

  The pitch L2 between adjacent grooves in the present invention, as shown in FIG. 2 and FIG. 3, is determined from one end of the opening of the groove on the surface opposite to the current collector of the electrode mixture layer. And the distance to the end on the same side of the opening of the adjacent groove. The pitch L2 between the adjacent groove portions is obtained by dividing the entire length of the two groove portions to be measured into 10 equal lengths, and measuring the pitch at the central portion in the extending direction of the groove portions in each divided portion. These are obtained as an average value.

  The depth of the groove is 70% or more of the thickness of the electrode mixture layer from the viewpoint of allowing the non-aqueous electrolyte to better penetrate into the active material present in the vicinity of the current collector of the electrode mixture layer. It is preferable that it is 100% (that is, it is particularly preferable that the groove reaches the current collector).

  In the non-aqueous electrolyte battery of the present invention, the groove satisfying the L1 and L2 is necessarily formed in the electrode mixture layer having a thickness of 100 μm or more. However, for the electrode mixture layer having a thickness of less than 100 μm, the L1 And a groove satisfying L2 may or may not be formed. For example, when only one of the positive electrode and the negative electrode has an electrode mixture layer with a thickness of 100 μm or more, and the other electrode has an electrode mixture layer with a thickness of less than 100 μm In the electrode mixture layer of the other electrode, a groove satisfying the L1 and L2 may or may not be formed. In addition, at least one of the positive electrode and the negative electrode has electrode mixture layers on both sides of the current collector, and the electrode mixture layer on one side has a thickness of 100 μm or more, and the electrode mixture layer on the other side. When the thickness of the electrode mixture layer is less than 100 μm, the electrode mixture layer on the other surface may or may not be formed with a groove that satisfies the L1 and L2.

  Further, when the electrode mixture layer is provided on both surfaces of the current collector and the groove portions satisfying the L1 and L2 are provided on both of them, the groove portion formed on the electrode mixture layer on one side and the electrode mixture layer on the other surface In the cross section of the electrode, for example, both of the grooves may be provided at positions corresponding to each other (here, “the two are provided at corresponding positions” means, for example, in FIG. In the cross section of the electrode shown, it means that the groove formed in the lower electrode mixture layer is located directly below the groove formed in the upper electrode mixture layer. In the specification, other modes such as those shown in FIGS. 2 and 3 are referred to as “provided in positions where they do not correspond”.

  Moreover, it is more preferable that the groove part formed in the electrode mixture layer on one side and the groove part formed in the electrode mixture layer on the other side are provided at positions where they do not correspond. For example, as described above, it is particularly preferable that the bottom of the groove reaches the current collector. However, when such a groove is formed, the surface of the current collector is scratched, and the current collector of the part is collected. Body strength may be reduced. In this case, if the groove formed on the electrode mixture layer on one side and the groove formed on the electrode mixture layer on the other side are provided at positions corresponding to each other, scratches on both sides of the current collector correspond to each other. By forming in the location to do, a part with very small thickness will arise locally in a collector, and there exists a possibility that it may be easy to tear at this part. However, when the groove portion formed in the electrode mixture layer on one side and the groove portion formed in the electrode mixture layer on the other surface are provided at positions that do not correspond to each other, The occurrence of this problem can be suppressed.

  In order to provide the groove part formed in the electrode mixture layer on one side and the groove part formed in the electrode mixture layer on the other side at positions where they do not correspond, for example, as shown in FIG. 2 and FIG. The groove part formed in the electrode mixture layer is formed at a position corresponding to the space between adjacent groove parts in the electrode mixture layer on one side, and the direction of the groove part formed on one side (the direction in which the groove part extends; the same applies hereinafter). ) And the direction of the groove formed on the other surface can be adopted.

  4 is a perspective view schematically showing an example of the other surface (back surface) of the electrode 10 shown in FIG. 1, and FIG. 5 is a partially enlarged view of the cross section along line AA of the electrode 10 in FIG. As shown in FIGS. 4 and 5, the plurality of groove portions 21a formed on the other surface of the electrode 10 are arranged so as to intersect with the plurality of groove portions 20a formed on one surface of the electrode 10 shown in FIG. By forming (therefore, the groove portion of the lower electrode mixture layer 21 is not observed in the cross section shown in FIG. 5 corresponding to the cross section taken along the line AA of FIG. 4), and the groove portion relating to the electrode mixture layer on one side, The groove part which concerns on the electrode mixture layer of an other surface can be provided in the position where both do not respond | correspond.

  1 and 4 show the electrode 10 having the linear groove portions 20a and 21a in a plan view, the groove portions may be linear in a plan view as described above. It may be bent or curved. However, from the viewpoint of facilitating the productivity of the electrode, it is more preferable that the groove is linear in a plan view.

  Moreover, there is no restriction | limiting in particular about the arrangement | sequence of the some groove part provided in an electrode mixture layer, as shown in FIG. 1, you may arrange | position substantially parallel (including parallel) mutually, and arrange in other forms You may do it. However, when a plurality of groove portions intersect, the active material may fall off from the edge of the intersecting portion, and the amount of active material that can contribute to the battery reaction may be reduced. Therefore, the groove portions should not intersect each other. Is preferred.

  For the positive electrode according to the nonaqueous electrolyte battery of the present invention, one having a positive electrode mixture layer containing a positive electrode active material, a conductive additive, a binder and the like is used on one side or both sides of a current collector.

Examples of the positive electrode active material include lithium-containing transition metal oxides represented by Li _{1 + x} MO ₂ (−0.1 <x <0.1, M: Co, Ni, Mn, etc.); LiMn ₂ O ₄ LiMn oxide: LiMn _x M _(1-x) O _{2 in} which part of Mn of LiMn ₂ O ₄ is substituted with another element; olivine type LiMPO ₄ (M: Co, Ni, Mn, Fe); LiMn _{0. 5} Ni _0.5 O ₂ ; Li _{(1 + a)} Mn _x Ni _y Co _(1-xy) O ₂ (−0.1 <a <0.1, 0 <x <0.5, 0 <y <0.5); and the like.

  Examples of the binder related to the positive electrode mixture layer include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), and polyvinylpyrrolidone (PVP).

  Examples of the conductive auxiliary agent related to the positive electrode mixture layer include acetylene black; ketjen black; carbon blacks such as channel black, furnace black, lamp black, and thermal black; carbon materials such as carbon fiber; Conductive fibers such as metal fibers; carbon fluoride; metal powders such as copper and nickel; organic conductive materials such as polyphenylene derivatives; and the like can be used.

  For the positive electrode, for example, a positive electrode mixture containing a positive electrode active material, a conductive additive and a binder is dispersed in a solvent (an organic solvent such as NMP or water) to form a positive electrode mixture-containing composition (paste, slurry, etc.). The positive electrode mixture-containing composition can be prepared, applied to one side or both sides of the current collector, dried, and subjected to a press treatment as necessary.

  Alternatively, a molded body may be formed using the positive electrode mixture, and a part or all of one side of the molded body may be bonded to the positive electrode current collector to form a positive electrode. Bonding of the positive electrode mixture molded body and the positive electrode current collector can be performed by press treatment or the like.

  As the current collector of the positive electrode, a metal foil such as aluminum or aluminum alloy, a punching metal, a net, an expanded metal, or the like can be used, but an aluminum foil is usually preferably used. The thickness of the positive electrode current collector is preferably 10 to 30 μm.

  The composition of the positive electrode mixture layer is, for example, 80.0 to 99.8% by mass of the positive electrode active material, 0.1 to 10% by mass of the conductive additive, and 0.1 to 10% by mass of the binder. It is preferable.

The filling density of the positive electrode active material in the positive electrode mixture layer is preferably 2.0 g / cm ³ or more, more preferably 2.4 g / cm ³ or more, from the viewpoint of further increasing the capacity of the battery. preferable. However, if the packing density of the positive electrode active material in the positive electrode mixture layer is too high, the density of the positive electrode mixture layer itself becomes too high, and the nonaqueous electrolyte solution may not easily penetrate into the positive electrode mixture layer. filling density of the positive electrode active material in the positive electrode mixture layer is more preferably is preferably 4.6 g / cm ³ or less, 4.0 g / cm ³ or less.

  The packing density of the positive electrode active material in the positive electrode mixture layer referred to in this specification is a value measured by the following method. The positive electrode is cut into a predetermined area, the mass is measured using an electronic balance with a minimum scale of 0.1 mg, the mass of the positive electrode mixture layer is obtained by subtracting the mass of the current collector, and the positive electrode in the positive electrode mixture layer is obtained. Multiplying the mass ratio of the active material, the mass of the positive electrode active material in the positive electrode mixture layer is calculated. On the other hand, the total thickness of the positive electrode was measured at 10 points with a micrometer having a minimum scale of 1 μm, and the volume of the positive electrode mixture layer was calculated from the average value obtained by subtracting the thickness of the current collector from these measured values and the area. To do. Then, the packing density of the positive electrode active material in the positive electrode mixture layer is calculated by dividing the mass of the positive electrode active material in the positive electrode mixture layer by the volume.

  The negative electrode according to the non-aqueous electrolyte battery of the present invention has a configuration in which a negative electrode mixture layer containing a negative electrode active material, a binder, and a conductive auxiliary agent as necessary is provided on one or both sides of a current collector. Things are used.

  Examples of the negative electrode active material include graphite materials such as natural graphite (flaky graphite), artificial graphite, and expanded graphite; graphitizable carbonaceous materials such as coke obtained by calcining pitch; furfuryl alcohol resin ( Carbon materials such as non-graphitizable carbonaceous materials such as amorphous carbon obtained by low-temperature firing of PFA), polyparaphenylene (PPP), and phenol resins. In addition to the carbon material, lithium or a lithium-containing compound can also be used as the negative electrode active material. Examples of the lithium-containing compound include lithium alloys such as Li—Al, and alloys containing elements that can be alloyed with lithium such as Si and Sn. Furthermore, oxide-based materials such as Sn oxide and Si oxide can also be used.

  As the binder for the negative electrode mixture layer, the same binders as those exemplified above as those that can be used for the positive electrode mixture layer can be used. Moreover, when making a negative electrode mixture layer contain a conductive support agent, the same thing as the various conductive support agents illustrated previously as what can be used for a positive mix layer can be used for the conductive support agent.

  For the negative electrode, for example, a negative electrode active material, a binder, and a negative electrode mixture containing a conductive auxiliary agent, if necessary, are dispersed in a solvent [an organic solvent such as N-methyl-2-pyrrolidone (NMP) or water]. Preparing a negative electrode mixture-containing composition (paste, slurry, etc.), applying the negative electrode mixture-containing composition to one or both surfaces of the current collector and drying, and subjecting to a press treatment as necessary Can be manufactured.

  Alternatively, a molded body may be formed using the negative electrode mixture, and a part or all of one side of the molded body may be bonded to the negative electrode current collector to form a positive electrode. Bonding of the negative electrode mixture molded body and the negative electrode current collector can be performed by press treatment or the like.

  For the current collector of the negative electrode, foil made of copper, copper alloy, nickel, nickel alloy, punching metal, net, expanded metal, or the like can be used, but copper foil is usually used. The thickness of the negative electrode current collector is preferably, for example, 5 to 30 μm.

  As a composition of a negative mix layer, it is preferable that a negative electrode active material shall be 80.0-99.8 mass%, for example, and a binder shall be 0.1-10 mass%. Moreover, when making a negative mix layer contain a conductive support agent, it is preferable that the quantity of the conductive support agent in a negative mix layer shall be 0.1-10 mass%.

From the viewpoint of further increasing the capacity of the battery, the packing density of the negative electrode active material in the negative electrode mixture layer (the packing density measured by the same method as the packing density of the positive electrode active material in the positive electrode mixture layer) is 1 it is preferably .5g / cm ³ or more, and more preferably 1.7 g / cm ³ or more. However, if the packing density of the negative electrode active material in the negative electrode mixture layer is too high, the density of the negative electrode mixture layer itself becomes too high, and the nonaqueous electrolyte may not easily penetrate into the negative electrode mixture layer. The density of the negative electrode mixture layer is preferably 3.0 g / cm ³ or less, and more preferably 2.8 g / cm ³ or less.

  In order to form the groove in the positive electrode mixture layer related to the positive electrode or the negative electrode mixture layer related to the negative electrode, for example, a method of roll pressing the electrode with a roll having protrusions on the surface can be adopted. The width L1 of the groove part, the pitch L2 between adjacent groove parts, and the depth of the groove part can be controlled by adjusting the width of the protrusion on the roll surface, the pitch between adjacent protrusions, and the height of the protrusion, respectively. . In addition, the shape and cross-sectional shape of the groove in plan view can be controlled by selecting the shape of the protrusion on the roll surface. Moreover, each said parameter regarding a groove part is controllable also by adjusting the element similar to a roll press by a flat press.

  In the nonaqueous electrolyte battery of the present invention, the positive electrode and the negative electrode are laminated electrode bodies laminated via separators, or wound electrodes formed by winding spirally after being laminated via separators. Used as a body.

  The separator preferably has a property (that is, a shutdown function) in which pores are blocked at 80 ° C. or higher (more preferably 100 ° C. or higher) and 170 ° C. or lower (more preferably 150 ° C. or lower). A separator used in a secondary battery or the like, for example, a microporous membrane made of polyolefin such as polyethylene (PE) or polypropylene (PP) can be used. The microporous film constituting the separator may be, for example, one using only PE or one using PP, or a laminate of a PE microporous film and a PP microporous film. There may be. The thickness of the separator is preferably 10 to 30 μm, for example.

  The non-aqueous electrolyte battery of the present invention is, for example, loaded with an electrode body having a laminated structure or a wound structure in the exterior body, and injecting the non-aqueous electrolyte solution into the exterior body to immerse the electrode body in the non-aqueous electrolyte solution Then, it is manufactured by sealing the opening of the exterior body. As the exterior body, it is possible to use a tubular exterior body (such as a rectangular tube or a cylindrical body) made of steel, aluminum, or aluminum alloy, or an exterior body composed of a laminated film on which metal is deposited.

  As the non-aqueous electrolyte, a solution prepared by dissolving an inorganic ion salt in the following non-aqueous solvent can be used.

  Examples of the solvent include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), γ-butyrolactone (γ-BL ), 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, dimethyl sulfoxide (DMSO), 1,3-dioxolane, formamide, dimethylformamide (DMF), dioxolane, acetonitrile, nitromethane, Methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative Aprotic organic solvents such as conductors, diethyl ether, and 1,3-propane sultone can be used alone or as a mixed solvent in which two or more are mixed.

The inorganic ion salt according to the non-aqueous electrolyte solution, for _{example, LiClO 4, LiPF 6, LiBF} 4, LiAsF 6, LiSbF 6, LiCF 3 SO 3, LiCF 3 CO 2, Li 2 C 2 F 4 (SO 3) 2 LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiC _n F _{2n + 1} SO 3 (n ≧ 2), LiN (RfOSO ₂ ) ₂ [where Rf is a fluoroalkyl group] There may be mentioned at least one selected. The concentration of these lithium salts in the electrolytic solution is preferably 0.6 to 1.8 mol / l, and more preferably 0.9 to 1.6 mol / l.

  In addition, vinylene carbonates, 1,3-propane sultone, diphenyl disulfide, cyclohexyl benzene, biphenyl are used for the purpose of further improving the battery safety, charge / discharge cycleability, and high-temperature storage properties of these non-aqueous electrolytes. Additives such as fluorobenzene and t-butylbenzene can also be added as appropriate.

  So far, the case where the nonaqueous electrolyte battery of the present invention is a secondary battery has been mainly described, but as described above, the nonaqueous electrolyte battery of the present invention can also take the form of a primary battery, for example, The positive electrode active material and the negative electrode active material may be appropriately selected from those used in conventionally known nonaqueous electrolyte primary batteries. In the case where the nonaqueous electrolyte battery of the present invention is a primary battery, configurations other than the positive electrode active material and the negative electrode active material can be the same as those described so far.

  The non-aqueous electrolyte battery of the present invention has a high capacity and can exhibit high power generation efficiency even when discharged with a large current. Therefore, particularly in the case of a secondary battery, it can be used as a power source for electric tools, hybrid cars, etc. In addition to being suitable for applications requiring discharge with a large current, it can be preferably used for the same applications as various applications in which conventionally known nonaqueous electrolyte batteries are used.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

Example 1
<Preparation of positive electrode>
An appropriate amount of NMP was added to a positive electrode mixture composed of lithium spinel manganate as a positive electrode active material: 93% by mass, PVDF as a binder: 3.4% by mass, and acetylene black as a conductive auxiliary agent: 3.6% by mass. The slurry was added and mixed well to prepare a positive electrode mixture-containing slurry.

The positive electrode mixture-containing slurry was applied to the surface of a current collector made of an aluminum foil having a thickness of 10 μm, and dried to form positive electrode mixture layers on both surfaces of the current collector. Thereafter, this was subjected to a press treatment using a roll press machine having a roll having a protrusion having a width of 400 μm, a pitch of 1.5 mm and a height of 140 μm on the surface, and the positive electrode mixture layers on both sides of the current collector were Grooves were formed on the surface. The formed groove portion has the cross-sectional shape shown in FIG. 2, the width L1 is 350 μm, the pitch L2 is 3 mm, and the depth is 100% of the thickness of the positive electrode mixture layer (the groove portion reaches the current collector surface). Met. The positive electrode mixture layer after the press treatment had a thickness of 150 μm per side of the current collector and a density of 2.4 g / cm ³ .

<Production of negative electrode>
Appropriate amount for negative electrode mixture composed of artificial graphite as negative electrode active material: 48.9% by mass and natural graphite: 48.9% by mass, and binder as CMC: 1.2% by mass and SBR: 1.0% by mass Was added and mixed well to prepare a negative electrode mixture-containing slurry.

The negative electrode mixture-containing slurry was applied to the surface of a current collector made of a copper foil having a thickness of 7 μm and dried to form negative electrode mixture layers on both sides of the current collector. Then, this was subjected to a press treatment using a roll press machine having a roll having a protrusion having a width of 1.5 μm, a pitch of 3 mm, and a height of 140 μm on the surface, and the negative electrode mixture layers on both sides of the current collector Grooves were formed on the surface. The cross-sectional shape of the formed groove portion and the positional relationship between the groove portion on one side and the other surface of the current collector are the shape and positional relationship shown in FIG. 2, the width L1 is 350 μm, the pitch L2 is 3 mm, and the depth is the negative electrode It was 100% of the thickness of the mixture layer (the groove portion reached the current collector surface). The negative electrode mixture layer after the press treatment had a thickness of 150 μm per side of the current collector and a density of 1.5 g / cm ³ .

<Battery assembly>
The positive electrode and the negative electrode were superposed through a PE microporous membrane separator (thickness: 18 μm), and further wound in a spiral shape to form a wound electrode body. This electrode body is put into a cylindrical battery case (outer can) having a diameter width of Φ18.3 mm and a height of 65 mm, and a non-aqueous electrolyte (ethylene carbonate and diethyl carbonate mixed at a volume ratio of 30:70 in a solvent containing LiPF ₆₎ Was dissolved at a concentration of 1 mol / l).

  After injecting the nonaqueous electrolyte, the battery case was sealed to produce a nonaqueous electrolyte battery (nonaqueous electrolyte secondary battery) having the structure shown in FIG.

  Here, the battery shown in FIG. 6 will be described. In the nonaqueous electrolyte battery shown in FIG. 6, the positive electrode 101 and the negative electrode 102 are spirally wound via the separator 103, and the nonaqueous electrode is used as an electrode body having a winding structure. It is accommodated in the battery case 105 together with the electrolytic solution 104. Note that in FIG. 6, the current collector used for manufacturing the positive electrode 101 and the negative electrode 102 is not illustrated in order to avoid complication.

  The battery case 105 is made of stainless steel, and an insulator 106 made of PP is disposed on the bottom of the battery case 105 prior to the insertion of the wound electrode body. The sealing plate 107 is made of aluminum and has a disk shape. A thin portion 107a is provided at the center of the sealing plate 107, and a pressure introduction port 107b for allowing the internal pressure of the battery to act on the explosion-proof valve 109 around the thin portion 107a. As a hole. And the protrusion part 109a of the explosion-proof valve 109 is welded to the upper surface of this thin part 107a, and the welding part 111 is comprised. The thin-walled portion 107a provided on the sealing plate 107, the protruding portion 109a of the explosion-proof valve 109, etc., only show a cut surface for easy understanding on the drawing, and the contour behind the cut surface is The illustration is omitted. In addition, the welded portion 111 of the thin-walled portion 107a of the sealing plate 107 and the protruding portion 109a of the explosion-proof valve 109 is also shown in an exaggerated state for the sake of easy understanding on the drawing.

  The terminal plate 108 is made of rolled steel, has a nickel-plated surface, and has a hat shape with a peripheral edge portion. The terminal plate 108 is provided with a gas discharge port 108a. The explosion-proof valve 109 is made of aluminum and has a disk shape, and a projection 109a having a tip portion is provided on the power generation element side (lower side in FIG. 6) at the center thereof, and a thin portion 109b is provided. As described above, the lower surface of the protruding portion 109a is welded to the upper surface of the thin portion 107a of the sealing plate 107 to constitute the welded portion 111. The insulating packing 110 is made of PP and has an annular shape. The insulating packing 110 is disposed at the upper portion of the peripheral edge of the sealing plate 107, and the explosion-proof valve 109 is disposed on the upper portion thereof, and insulates the sealing plate 107 and the explosion-proof valve 109. The gap between the two is sealed so that the non-aqueous electrolyte does not leak between the two. The annular gasket 112 is made of PP, the lead body 113 is made of aluminum, the sealing plate 107 and the positive electrode 101 are connected to each other, an insulator 114 is disposed on the upper part of the wound electrode body, the negative electrode 102 and the battery case The bottom of 105 is connected by a lead body 115 made of nickel.

  In this battery, the thin-walled portion 107a of the sealing plate 107 and the protruding portion 109a of the explosion-proof valve 109 are in contact with each other at the welded portion 111, the peripheral portion of the explosion-proof valve 109 and the peripheral portion of the terminal plate 108 are in contact with each other. Since the positive electrode 101 and the terminal plate 108 are connected to the sealing plate 107 by the positive lead body 113, the positive electrode 101 and the terminal plate 108 are electrically connected by the lead body 113, the sealing plate 107, the explosion-proof valve 109, and their welded portions 111. Connection is obtained and functions normally as an electrical circuit.

  When an abnormal situation occurs in the battery, such as exposure of the battery to a high temperature, gas is generated inside the battery and the internal pressure of the battery increases, the internal pressure increases, so that the central portion of the explosion-proof valve 109 moves in the internal pressure direction ( In FIG. 6, the thin-walled portion 107 a is deformed in the upper direction), and the thin-walled portion 107 a integrated with the welded portion 111 is applied to break the thin-walled portion 107 a or the protruding portion 109 a of the explosion-proof valve 109. After the welded portion 111 between the sealing plate 107 and the thin portion 107a of the sealing plate 107 is peeled off, the thin portion 109b provided on the explosion-proof valve 109 is cleaved and gas is discharged from the gas discharge port 108a of the terminal plate 108 to the outside of the battery. Designed to prevent battery rupture.

Comparative Example 1
The press treatment of the positive electrode and the negative electrode was carried out in the same manner as in Example 1 except that a roll press machine equipped with a roll having no protrusions on the surface was used and no groove was formed in the positive electrode mixture layer and the negative electrode mixture layer. Thus, a non-aqueous electrolyte battery (non-aqueous electrolyte secondary battery) was produced.

Comparative Example 2
The positive electrode and the negative electrode were treated in the same manner as in Example 1 except that a roll press machine having a roll having a protrusion having a width of 400 μm, a pitch of 1.5 mm, and a height of 140 μm was used for the press treatment of the positive electrode and the negative electrode. Produced. This positive electrode is the same as the positive electrode produced in Example 1 except that the pitch L2 of the grooves formed in the positive electrode mixture layer is 1.5 mm, and this negative electrode is formed in the negative electrode mixture layer. The negative electrode produced in Example 1 is the same as the negative electrode except that the pitch L2 of the groove is 1.5 mm.

  A nonaqueous electrolyte battery (nonaqueous electrolyte secondary battery) was produced in the same manner as in Example 1 except that the positive electrode and the negative electrode were used.

  For the non-aqueous electrolyte batteries of Example 1 and Comparative Examples 1 and 2, constant current charging at a current value of 1 C until the voltage reached 4.2 V, followed by constant current charging at a voltage of 4.2 V— Constant voltage charging (total charging time: 1.5 hours) was performed. Thereafter, each battery is discharged at a predetermined current value (1.0 C, 1.8 C, 2.0 C, 2.5 C and 5 C) until the voltage becomes 2.5 V, and the discharge capacity at each discharge current value. (Discharge capacity per mass of battery) was measured. These results are shown in Table 1.

  As shown in Table 1, the non-aqueous electrolyte battery of Example 1 using a positive electrode having a groove with a proper configuration in the positive electrode mixture layer and a negative electrode having a groove with a proper configuration in the negative electrode mixture layer was discharged. When the current value at the time is increased, the discharge capacity is higher than the battery of Comparative Example 1 using the positive electrode having the positive electrode mixture layer having no groove and the negative electrode having the negative electrode mixture layer having no groove, It can be seen that the power generation efficiency is high even when discharging with a large current.

  The battery of Comparative Example 2 uses a positive electrode with a narrow pitch L2 of grooves formed in the positive electrode mixture layer and a negative electrode with a narrow pitch L2 of grooves formed in the negative electrode mixture layer. Compared to a battery, the capacity decreases as the current value during discharge increases. This is thought to be because the number of the groove portions formed in the positive electrode mixture layer and the negative electrode mixture layer is increased by narrowing the pitch of the groove portions, so that the amount of the active material in these mixture layers is reduced. .

DESCRIPTION OF SYMBOLS 10 Electrode 20,21 Electrode mixture layer 20a, 21a Groove part 30 Current collector 101 Positive electrode 102 Negative electrode 103 Separator

Claims (5)

A non-aqueous electrolyte battery configured by sealing an electrode body formed with a separator interposed between a positive electrode and a negative electrode, and an exterior body containing a non-aqueous electrolyte solution,
The positive electrode and the negative electrode have an electrode mixture layer containing an active material on one side or both sides of a current collector,
The electrode mixture layer present on at least one surface of at least one of the positive electrode and the negative electrode has a thickness of 100 μm or more and a plurality of grooves having openings on the surface opposite to the current collector Have
The groove portion has a width L1 of 100 to 800 μm,
The non-aqueous electrolyte battery, wherein a pitch L2 between the adjacent groove portions is 2 to 5 mm.   2. The non-transparent structure according to claim 1, wherein the plurality of groove portions of the electrode mixture layer have a trapezoidal shape in which a cross-sectional shape in a width direction increases in width toward a surface opposite to the current collector of the electrode mixture layer. Water electrolyte battery. The non-aqueous electrolyte battery according to claim 1, wherein a filling density of the active material in the electrode mixture layer of the negative electrode is 1.5 to 3.0 g / cm ³ . The nonaqueous electrolyte battery according to any one of claims 1 to ³ , wherein a packing density of the active material in the electrode mixture layer of the positive electrode is 2.0 to 4.6 g / cm ³ .   The nonaqueous electrolyte battery according to claim 1, wherein the separator has a thickness of 20 μm or less.

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