JP2007250537A - Electrode plate for non-aqueous electrolyte secondary battery, and non-aqueous secondary battery using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for non-aqueous electrolyte secondary battery which uses a high capacity active material, and can achieve reduction of stress at both ends in width direction of the current collector at the time of expansion and contraction by storage of lithium ions without remarkable deterioration of capacity, and to provide a non-aqueous electrolyte secondary battery using the same. <P>SOLUTION: The electrode plate 20 for non-aqueous electrolyte secondary battery comprises a current collector 22 and an electrode active material layer 24 including an electrode active material capable of storage and release of lithium ions. The electrode active material layer 24 is composed of a first active material layer 21 formed at the center of the current collector 22 and a second active material layer 23 formed at the both end parts in width direction of the current collector 22. The thickness of the second active material layer 23 is larger by more than 0% and 50% or less than that of the first active material layer 21. A non-aqueous electrolyte secondary battery using this is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a nonaqueous electrolyte secondary battery electrode plate having a current collector and an electrode active material layer formed on the surface of the current collector, and a nonaqueous electrolyte secondary battery using the same.

  In recent years, electrode materials containing elements such as Si (silicon) and Sn (tin) have attracted attention as electrode active materials (hereinafter also referred to as active materials) for increasing the capacity of non-aqueous electrolyte secondary batteries. For example, the theoretical discharge capacity of Si is about 4199 mAh / g, which is about 11 times the theoretical discharge capacity of graphite.

  However, these active materials undergo a large change in structure when they absorb lithium ions and expand. As a result, the active material particles are cracked or the active material layer is peeled off from the current collector, resulting in a decrease in electronic conductivity between the active material and the current collector, resulting in a decrease in battery characteristics such as cycle characteristics. To do.

  Therefore, although the discharge capacity is slightly reduced, attempts have been made to reduce expansion and contraction by using Si, Sn oxides, nitrides, or oxynitrides.

  In addition, it has been proposed that an active material layer is provided with an expansion space in advance when lithium ions are stored.

  For example, Patent Document 1 discloses a non-aqueous electrolyte secondary in which a thin film made of a metal alloyed with Li or an alloy containing this metal is formed on a current collector made of a material that is not alloyed with lithium (Li). A battery electrode plate (hereinafter also referred to as an electrode plate) is disclosed. In this conventional example, an uneven electrode active material layer is selectively formed in a predetermined pattern on a current collector, and a photoresist method and a plating technique are applied to the formation of the uneven electrode material layer. . Furthermore, the content which avoids destruction of an active material is disclosed by the space | gap between the active materials formed in columnar shape absorbing the volume expansion of an active material. In addition, a non-aqueous electrolyte secondary that is made to face a positive electrode active material through a separator in the same manner as a conventional battery, using an electrode including an active material layer that is formed in a concavo-convex pattern on a current collector A battery is disclosed.

Patent Document 2 includes a plated layer at both ends in the width direction of the current collector to prevent cracking of the plated electrode layer during repeated charging / discharging cycles and winding in a Li alloy plating type electrode. No configuration is disclosed.
JP 2004-127561 A JP-A-8-130005

  However, the electrode plate having the configuration described in Patent Document 1 has a large stress acting on the current collector because the particles constituting the active material layer significantly expand and contract during charge and discharge, and the width direction of the current collector is large. Breaking is likely to occur at the ends. In addition, when the portion where the active material layer is not formed is provided at both end portions in the width direction of the current collector as in the electrode having the configuration described in Patent Document 2, the capacity is greatly reduced. The current collector material in the exposed portion of the current collector is likely to be scraped, and fine powder is generated in the battery assembly process, which may cause variations in battery performance.

The present invention solves the above-mentioned conventional problems, and is able to remarkably reduce stress at both ends in the width direction of the current collector foil during expansion and contraction using a high-capacity active material and occlusion of lithium ions. It aims at providing the electrode plate for nonaqueous electrolyte secondary batteries which can be implement | achieved without capacity reduction, and a nonaqueous electrolyte secondary battery using the same.

In order to solve the conventional problems, an electrode plate for a non-aqueous electrolyte secondary battery according to the present invention includes a current collector and an electrode active material capable of inserting and extracting lithium ions formed on the current collector. An electrode active material layer comprising:
The electrode active material layer includes a first active material layer formed at the center of the current collector and a second active material layer formed at both ends in the width direction of the current collector and thinner than the first active material layer. It is characterized by comprising an active material layer.

  In the electrode plate of the present invention, the thickness of the second active material layer is 0% or more and 50% or less of the thickness of the first active material layer. Further, the electrode active material layer is a layer produced by a vapor phase method.

  When the electrode plate for a non-aqueous electrolyte secondary battery having this configuration is used, it is possible to reduce the stress on both ends in the width direction of the current collector, so that the current collector is prevented from being broken. I can do it.

The battery of the present invention includes a positive electrode plate containing a positive electrode active material capable of occluding and releasing lithium ions, a negative electrode plate made of the electrode plate for a nonaqueous electrolyte secondary battery of the present invention, and a separator. A battery comprising an electrode plate group and an electrolyte having lithium ion conductivity,
The electrode plate group is formed by winding or folding a positive electrode plate and an electrode plate in the length direction via a separator.

  The non-aqueous electrolyte secondary battery having this configuration can be a high-capacity and highly reliable non-aqueous electrolyte secondary battery by using a highly reliable non-aqueous electrolyte secondary battery electrode plate.

  According to the electrode plate for a non-aqueous electrolyte secondary battery and the non-aqueous electrolyte secondary battery using the same according to the present invention, a current collector end using a high-capacity active material and during expansion and contraction of the active material due to occlusion of lithium ions By reducing the stress on the part, it is possible to prevent the current collector from being broken. As a result, a battery with high capacity and high reliability can be obtained.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment)
FIG. 1 is a schematic plan view of an electrode plate according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view showing a cross-sectional structure taken along line AA ′ in FIG. 1 and 2, the same reference numerals are used for the same components. 1 and 2, the electrode plate 20 has a current collector 22 and an electrode active material layer 24 formed on the surface of the current collector 22. As shown in FIG. 2, the electrode active material layer 24 may be formed on both surfaces of the current collector 22, or the electrode active material layer 24 may be formed only on one surface of the current collector 22. The electrode active material layer 24 is formed at the first active material layer 21 formed at the center of the current collector 22 and at both ends in the width direction of the current collector 22, and is thinner than the first active material layer. A second active material layer 23. The second active material layer 23 is formed with a predetermined width W at both ends in the width direction of the current collector 22.

Furthermore, the thickness of the second active material layer 23 is greater than 0% and equal to or less than 50% with respect to the thickness of the first active material layer 21. Here, the first active material layer 21 formed in the central portion of the current collector 22 is an active material layer that is opposed to the positive electrode plate during battery construction and is involved in charge and discharge, and has a generally uniform thickness. Is formed. Further, both end portions of the current collector 22 in the width direction have a certain area as shown in FIG. 1 and do not mean end cross sections of the current collector 22.

  In the conventional electrode plate, the electrode active material layer is provided almost uniformly up to the end of the current collector, or as shown in Patent Document 2 described above, the electrodes are formed at both ends in the width direction of the current collector. A region where no active material layer was formed was provided.

  In the conventional electrode plate in which the electrode active material layer is provided almost uniformly up to the end in the width direction of the current collector, the stress accompanying the expansion and contraction of the electrode active material layer due to charge / discharge is near the center of the current collector. It occurs to the same extent at the end in the width direction. On the other hand, the practical mechanical strength of the current collector is defined by the tensile strength of the current collector material near the center of the current collector, but is practical mechanical strength at the widthwise end of the current collector. Is defined by the tear strength of the current collector material. For example, when Cu foil is used as the current collector material, a minute scratch may occur on the cut surface of the current collector in the electrode slit process during the battery manufacturing process, and the microscopic damage may occur during expansion / contraction due to charge / discharge. The current collector based on the crack portion tends to break.

  On the other hand, in the electrode plate 20 of the present invention, the thickness of the electrode active material layer (second active material layer 23) at the end in the width direction of the current collector 22 is the same as that of the electrode active material layer (first in the width direction). Therefore, the stress on the current collector 22 due to expansion and contraction due to charge / discharge can be reduced. Therefore, even when charging / discharging is repeated, breakage of the current collector 22 and the electrode plate 20 with the current collector end as a base point can be prevented.

  On the other hand, in order to prevent cracking of the electrode active material layer itself, as disclosed in Patent Document 2, it is disclosed that regions where no electrode active material layer is formed are provided at both ends in the width direction of the current collector. In the case of Patent Document 2, there is a large difference in stress applied to the current collector in the current collector end region where the electrode active material layer is not formed at all and the electrode active material layer formation region. Current collector damage is likely to occur at the boundary between the two regions. In addition, if there is no electrode active material layer on the electrode plate at a position opposite to the positive electrode plate, lithium deposition occurs remarkably and the reliability of the battery is lowered. Therefore, the alignment of the positive electrode plate and the electrode plate is high. Accuracy is required and productivity is reduced. Furthermore, the current collector foil is exposed in the region where the electrode active material layer at both ends in the width direction of the current collector is not formed, and the current collector is exposed when slitting or winding the electrode plate in the battery manufacturing process. There is a high possibility that the part will be in sliding contact with the process equipment. Therefore, fine powder made of the current collector material may be generated by scraping or dropping off the surface of the current collector 22. Such a fine powder of the metal material becomes a factor of lowering the battery reliability.

  On the other hand, in the configuration of the electrode plate 20 of the present invention, the second active material layer 23 is formed up to the end of the current collector 22 in the width direction. The difference in stress applied to the current collector 22 between the formation region of the first active material layer 22 is small. Therefore, even if charging / discharging is repeated, the current collector 22 is hardly damaged at the boundary between the two regions. Further, since the second active material layer 23 is formed up to the end in the width direction of the current collector 22, lithium deposition is slight even when the positive electrode plate is misaligned. Reduced reliability can be prevented. Further, since the current collector 22 is covered with the second active material layer 23 up to the end in the width direction, the material of the current collector 22 is hardly scraped even after handling in the battery manufacturing process, and the generation of metal fines is generated. It is possible to prevent a decrease in battery reliability due to.

The width W of the region where the second active material layer 23 is formed in the width direction of the current collector 22 is preferably 1 mm or more and 10 mm or less. If this width W is less than 1 mm, the effect of preventing breakage at the end of the current collector is small, and it is desirable for the width W not to exceed 10 mm in order to obtain a battery with a high energy density. The width W is normally constant over the entire length of the electrode plate 20, but need not be constant as long as the effect of the present invention is not impaired. Further, the width of the second active material layer 23 formed at one end of the current collector 22 may be the same as the width of the second active material layer 23 formed at the other end. May be.

  The active material contained in the electrode active material layer 24 (the first active material layer 21 and the second active material layer 23) is not particularly limited as long as it reacts electrochemically with lithium. Silicon simple substance, silicon alloy, compound containing silicon and oxygen, compound containing silicon and nitrogen, simple substance of tin, tin alloy, compound containing tin and oxygen, which has relatively high reactivity with lithium and can be expected to have a high capacity And at least one selected from the group consisting of compounds containing tin and nitrogen. It is because the improvement degree by this invention becomes remarkable.

  The thickness of the first active material layer 21 at the center of the current collector 22 varies depending on the performance of the battery to be manufactured, but is generally in the range of 3 to 40 μm. When the thickness of the first active material layer 21 is less than 3 μm, the proportion of the active material in the entire battery decreases, and the energy density of the battery decreases. Further, when the thickness of the first active material layer 21 exceeds 40 μm, the active material layer tends to be peeled off, or the current collector 22 and the first active material layer due to expansion / contraction of the active material layer during charge / discharge. The stress at the interface with the material layer 21 is increased, and even when the configuration of the present invention is used, the current collector is easily deformed.

  From the viewpoint of reactivity with lithium, the active material is preferably amorphous or low crystalline. The term “low crystallinity” as used herein refers to a region where the crystal grain size is 50 nm or less. Note that the grain size of the crystal grains is calculated by the Scherrer equation from the half-value width of the peak with the highest intensity in the diffraction image obtained by X-ray diffraction analysis. Amorphous means having a broad peak in the range of 2θ = 15 to 40 ° in a diffraction image obtained by X-ray diffraction analysis.

  A metal foil containing copper, nickel, or the like can be used for the current collector 22. The thickness of the current collector 22 is preferably 4 to 30 μm, more preferably 5 to 10 μm, from the viewpoints of strength, volumetric efficiency as a battery, and ease of handling. The surface of the current collector 22 may be smooth, but in order to increase the adhesion strength with the electrode active material layer 24, there may be unevenness of about Ra = 0.1 to 4 μm. The unevenness on the surface of the current collector also has the effect of forming voids between the particles constituting the electrode active material layer 24. From the viewpoints of adhesive force, cost, etc., Ra = 0.4 to 2.5 μm is more preferable.

  The electrode plate 20 in the present embodiment can be manufactured by the following method, for example. 3 and 4 are schematic views illustrating an example of a manufacturing apparatus for configuring the electrode plate 20 in the present embodiment, and FIG. 4 is a schematic perspective view illustrating an example of a shield moving mechanism described later. In FIG. 3, the inside of the vacuum chamber 2 is exhausted by the exhaust pump 1. The current collector 22 unwound from the unwinding roll 8 in the vacuum chamber 2 travels along the peripheral surfaces of the transport roller 5 and the cylindrical first can 6 and the second can 7, It is wound up. The current collector 22 used here is a sheet-like foil made of copper, nickel or the like. In the active material application source 9, silicon or tin is put in a crucible or the like. The active material application source 9 is heated by a heating device (not shown) such as an electron beam, and silicon or tin evaporates.

When the current collector 22 is exposed to silicon, tin, or the like flying from the active material application source 9 in the state along the first can 6 in the opening of the shielding plate 10, silicon or tin is deposited on the current collector 22. A first active material layer 21 (not shown) is formed. Next, when the current collector 22 is exposed to silicon, tin, or the like flying from the active material application source 9 in a state along the second can 7, the first active material layer of silicon or tin is also formed on the other surface. 21 (not shown) is formed. At this time, a linear shield 41 that is close to the first can 6 and the second can 7 and is parallel to the traveling direction of the current collector 22.
However, it is installed in multiple strips at a predetermined distance from the current collector 22 and the active material layer. Part of the active material flying from the evaporation source is prevented from adhering to the current collector 22 by the linear shield 41. Therefore, the second active material layer 23 can be formed by reducing the thickness of the active material layer formed on the current collector 22 at a position facing the linear shield 41. Note that a part of the linear shield 41 may be in contact with the current collector 22 or the active material layer to the extent that the formation of the second active material layer 23 is not affected.

  As the amount of active material deposited on the linear current collector 41 increases, the area where the active material layer becomes thinner spreads. Therefore, when performing film formation for a long time, it is desirable to move the linear shield 41 by the shield moving mechanism. This shield moving mechanism may be a system such as a shield moving mechanism 42B that moves the linear shield 41 between the delivery reel 44 and the collection reel 45, or a shield that circulates the linear shield 41. A system like the moving mechanism 42A may be used. When the shield moving mechanism has the delivery reel 44 and the recovery reel 45 as in the shield moving mechanism 42B, a new linear shield 41 is always provided, so that the active material at the opposing portion by the linear shield 41 is provided. The degree of layer thickness reduction is constant. In addition, when the shield moving mechanism is a cyclic system like the shield moving mechanism 42A, as shown in FIG. 4, an active material attached to the linear shield 41 is provided by providing a highly bent portion 43 in the middle. Most of the material is dropped off, whereby the active material layer thickness reduction degree of the opposing portion by the linear shield 41 can be made constant.

  As the linear shield 41, a linear long body made of a heat-resistant resin such as a metal wire such as stainless steel, a metal band, or polyimide can be used. The diameter or width of the linear shield 41 varies depending on the width of the second active material layer 23 to be manufactured and the shape of the battery to be manufactured, but the width W of the second active material layer 23 is set at the time of a slit described later. It suffices to have a width that can be secured.

  After the electrode active material layer 24 is formed on the current collector 22, a slit is formed for the battery manufacturing process. The slit is made at a position facing the linear shield 41, that is, along the second active material layer 23. As a result, the electrode plate 20 having the second active material layer 23 can be formed at both ends in the width direction of the current collector 22.

  The formation state of the second active material layer 23 includes the thickness, diameter and width of the linear shield 41, the distance between the linear shield 41 and the current collector 22, the active material application source 9 and the current collector 22. The width and thickness of the second active material layer 23 can be adjusted depending on the distance of the distance. The linear shield 41 and the current collector 22 may be partially in contact with each other, and the distance between them is preferably about 0 to 80 mm in order to limit the width of the second active material layer 23. The distance between the linear shield 41 and the current collector 22 is not more than four times the diameter or width of the linear shield 41. The second active material layer 23 is provided by the effect of the linear shield 41. Desirable above. The distance between the active material application source 9 and the current collector 22 is preferably about 100 to 600 mm in the case of using a vapor phase method such as a vacuum evaporation method from the viewpoint of film thickness distribution and material utilization efficiency.

  When forming an active material layer of a compound containing silicon and oxygen, a compound containing silicon and nitrogen, a compound containing tin and oxygen, or a compound containing tin and nitrogen, oxygen gas or nitrogen gas is used as a gas. The electrode plate 20 of the present invention can be obtained by introducing silicon through the introduction tube 11 and evaporating silicon or tin from the active material application source 9 in these gas atmospheres or in the ionized atmosphere thereof. In the case of ionizing a gas, application of a high frequency, use of an ion gun, etc. are effective for improving gas reactivity.

  The manufacturing method of the electrode active material layer 24 having the configuration of the present invention is not particularly limited as long as the structure of the present invention can be obtained, but a vapor phase method (dry process, such as a vapor deposition method, a sputtering method, a CVD method). ) Is preferably used. When the vapor phase method is used as in the manufacturing method described above, control of the formation thickness, width, formation position, and the like of the electrode active material layer 24 (the first active material layer 21 and the second active material layer 23) can be controlled. This is because it is easier than other methods.

The electrode plate 20 obtained by such a method includes a positive electrode plate containing a commonly used positive electrode active material such as LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , a separator made of a microporous film, etc. A nonaqueous electrolyte secondary battery can be produced by using lithium phosphate or the like together with an electrolyte having lithium ion conductivity having a generally known composition in which cyclic carbonates such as ethylene carbonate and propylene carbonate are dissolved.

  Further, the electrode of the present invention can be applied to various shapes of nonaqueous electrolyte secondary batteries, and the shape and sealing form of the battery are not particularly limited, but the present invention is particularly a folding type or wound type secondary battery. It is effective against. When applied to a wound nonaqueous electrolyte secondary battery, it is preferable to have the following configuration. This will be described with reference to the drawings.

  FIG. 5 is a schematic cross-sectional view of a wound nonaqueous electrolyte secondary battery of the present invention. In FIG. 5, the positive electrode 31 and the strip-shaped electrode plate 20 of the present invention are wound together with a strip-shaped separator 33 arranged between them and wider than the bipolar plates to form a plate group 32. . A positive electrode lead 34 made of aluminum or the like is connected to the positive electrode 31, and one end thereof is connected to a sealing plate 39 in which an insulating packing 40 made of polypropylene or the like is arranged on the periphery. An electrode lead 35 made of copper or the like is connected to the electrode plate 20, and one end thereof is connected to a battery can 38 that accommodates the electrode plate group 32. For example, a part of the second active material layer 23 is peeled off to expose the current collector 22, and the electrode lead 35 is electrically connected thereto by welding or the like. Alternatively, a slightly exposed portion may be formed in the current collector 22 in advance, and the electrode lead 35 may be connected thereto. An upper insulating ring 36 and a lower insulating ring 37 are arranged above and below the electrode plate group 32, respectively. The electrode plate group 32 is impregnated with the above-described electrolyte (not shown) having lithium ion conductivity. The opening of the battery can 38 is closed with a sealing plate 39.

  Here, the thickness of the second active material layer 23 formed at the both ends in the width direction on the current collector 22 formed as the electrode plate 20 is the first thickness formed at the central portion on the current collector 22. One active material layer 21 has a region exceeding 0% and not more than 50% with respect to the thickness. Thereby, even if the electrode active material layer 24 due to charging / discharging repeatedly expands and contracts, it is possible to prevent breakage with the end of the current collector 22 as a base point. Note that the thickness of the second active material layer 23 is not necessarily greater than 0% and not more than 50% with respect to the thickness of the first active material layer 21 over the entire length of the electrode plate 20. For the reasons described above, deviating from the above range only for a part of the electrode plate does not impair the gist of the present invention.

  In the following, the present invention will be explained by specific examples.

Example 1
Furukawa Circuit Foil Co., Ltd. roughened copper foil (thickness 35 microns, first surface Ra = 2 microns, second surface Ra = 1 microns) current collector on the first surface An electrode active material layer was formed by a vacuum vapor deposition method to produce an electrode. After evacuating the vacuum chamber to 0.005 Pa, the electrode active material layer is evaporated by heating silicon in an oxygen-introducing atmosphere (flow rate 30 sccm) using a 270 degree deflection electron gun manufactured by JEOL Ltd., This was done by depositing on a current collector. The first active material layer is formed by being deposited on the current collector at a deposition rate of 20 nm / second so that the thickness of the second active material layer is about 25% of the thickness of the first active material layer. The position of the shielding part was adjusted to about 20 mm from the current collector. The electrode material layer has a repeating structure in which the first active material layer is formed in the width direction of the current collector for about 58 mm and then the second active material layer is formed about 2 mm. Next, it cut | disconnects using the razor blade along the centerline vicinity of the 2nd active material layer, the 1st active material layer formed in the center part of an electrical power collector, and the edge part of the width direction of an electrical power collector The electrode which consists of the 2nd active material layer formed in this was obtained. In SEM observation of the polished cross section, the thickness of the second active material layer was 5 microns, and the thickness of the first active material layer was 20 microns.

  The prepared electrode (60 mm wide, 4 m long) was pressed at a tension of 1.2 kg and a bending angle of 160 degrees (obtuse angle) so that the active material layer was in contact with the height direction corner of the quartz quadrangular prism, and the speed was 2 m / Ran in minutes. The angle at which the electrode slid in the quartz quadrangular column after running the electrode for 1 m was observed with an optical microscope. FIG. 6 shows the result. In FIG. 6, the white part is the surface of the quartz quadrangular prism, and the black part is the space. As shown in FIG. 6, the surface of the quartz square column near the corner where the electrode slid was hardly contaminated due to the fine powder peeling off from the electrode (FIG. 6). In addition, on the surface of the active material layer on the electrode, the sliding trace generated by sliding with the corner of the quartz quadrangular column could not be visually confirmed.

(Comparative Example 1)
An electrode active material layer was formed on the same current collector as in Example 1 by vacuum vapor deposition to produce an electrode. The electrode active material layer was formed by evaporating silicon in an oxygen-introduced atmosphere and depositing it on the current collector using the same method and conditions as in Example 1. In addition, the electrode active material layer is formed in the central portion of the current collector, and a region where the active material layer is not formed is provided by masking in advance with another tape-shaped copper foil in the length direction of the current collector. . The electrode material layer has a repetitive structure in which the first active material layer continues for about 58 mm in the width direction of the current collector, and then the active material layer is not formed, and the exposed portion of the copper foil is formed about 2 mm. did. Next, cut both ends along the length direction of the exposed portion of the copper foil with a razor blade to expose the copper foil without forming the second active material layer at both ends of the current collector in the width direction. An electrode (60 mm wide, 4 m long) was obtained. From the SEM observation of the polished cross section, the thickness of the first active material layer was 20 microns.

  The produced electrode was made to face a quartz prism in the same arrangement as in Example 1, and slid at a speed of 2 m / min with a tension of 200 g / cm in the width direction. After traveling for 1 m, the corner of the quartz quadrangular column where the electrode slid was observed with an optical microscope in the same manner as in Example 1. In FIG. 7, the white portion is the surface of the quartz quadrangular prism, and the black portion is the space. As shown in FIG. 7, the copper powder peeled off from the current collector was observed as white dots on the surface of the quartz square column near the corner where the electrode slid. On the other hand, on the surface of the exposed portion of the copper foil of the electrode, sliding traces generated by sliding with the corners of the quartz quadrangular prism were visually confirmed.

  An electrode plate for a non-aqueous electrolyte secondary battery according to the present invention and a non-aqueous electrolyte secondary battery using the same are assembled even if a high-capacity active material is used and a current collector having a rough surface is used. Since the current collector can be less worn and the reliability of the battery is improved, it is useful as a nonaqueous electrolyte secondary battery electrode and a nonaqueous electrolyte secondary battery using the same.

  In addition, an electrochemical capacitor that has improved energy density by changing the active material of one electrode of the electric double layer capacitor from carbon black to graphite and changing the electrolyte to a non-aqueous electrolyte containing lithium ions has been studied. ing. By using the electrode plate of the present invention instead of the graphite electrode of such an electrochemical capacitor, the reliability of the electrochemical capacitor can be improved.

Schematic plan view of an electrode plate in an embodiment of the present invention Schematic sectional view of an electrode plate in an embodiment of the present invention Schematic which shows an example of the manufacturing apparatus in embodiment of this invention The schematic perspective view which shows an example of the shield moving mechanism in embodiment of this invention Schematic sectional view of a wound nonaqueous electrolyte secondary battery in an embodiment of the present invention Surface micrograph of a stone prism in an embodiment of the present invention Surface micrograph of stone prism in comparative example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust pump 2 Vacuum tank 3 Winding roll 5 Conveyance roller 6 1st can 7 2nd can 8 Unwinding roll 9 Active material provision source 10 Shielding plate 11 Gas introduction pipe 20 Electrode plate 21 1st active material layer 22 Current collection Body 23 Second active material layer 24 Electrode active material layer 31 Positive electrode plate 32 Electrode plate group 33 Separator 34 Positive electrode lead 35 Electrode lead 36 Upper insulating ring 37 Lower insulating ring 38 Battery can 39 Sealing plate 40 Insulating packing 41 Linear shield 42A, 42B Shield moving mechanism 43 High bending portion 44 Delivery reel 45 Collection reel

Claims (4)

An electrode plate for a nonaqueous electrolyte secondary battery, comprising: a current collector; and an electrode active material layer containing an electrode active material capable of inserting and extracting lithium ions formed on the current collector,
The electrode active material layer is formed at a first active material layer formed at the center of the current collector and at both ends in the width direction of the current collector, and is thinner than the first active material layer. An electrode plate for a non-aqueous electrolyte secondary battery, comprising: 2 active material layers.   2. The nonaqueous electrolyte secondary battery according to claim 1, wherein the thickness of the second active material layer is 0% or more and 50% or less of the thickness of the first active material layer. Electrode plate.   The electrode plate for a nonaqueous electrolyte secondary battery according to claim 1, wherein the negative electrode material layer is a layer produced by a vapor phase method. An electrode plate group comprising a positive electrode plate containing a positive electrode active material capable of inserting and extracting lithium ions, a negative electrode plate comprising the electrode plate for a non-aqueous electrolyte secondary battery according to claim 1, and a separator. When,
A non-aqueous electrolyte secondary battery comprising a lithium ion conductive electrolyte, wherein the electrode plate group includes a length of the positive electrode plate and the electrode plate for the non-aqueous electrolyte secondary battery through the separator. A non-aqueous electrolyte secondary battery characterized by being wound or folded in a direction.

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