JP2009164011A - Method of manufacturing electrode for lithium secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for a lithium secondary battery having high productivity and excellent cycle characteristics. <P>SOLUTION: A vacuum evaporator 100 includes a chamber 1, a vacuum pump 2, an evaporation source 3 and a vapor deposition region 20. The method includes a step (A), wherein there is arranged a collector 4 having a plurality of protrusions on its surface in the vapor deposition region and a first active material layer is formed by supplying a first evaporation material on the collector from the evaporation source along a direction inclined to a normal line N of the collector, and a step (B), wherein there is arranged a collector, on which the first active material layer is formed, in the vapor deposition region, and a second active material layer is formed by supplying a second evaporation material on the collector from the evaporation source along a direction inclined to a normal line of the collector. In the step (A), a product of a vacuum degree P<SB>1</SB>Pascal of the chamber and the minimum distance L<SB>(1)min</SB>meter of the surface of the collector and the evaporation source is ≥0.01, and in the step (B), a product of a vacuum degree P<SB>2</SB>Pascal of the chamber and the minimum distance L<SB>(2)max</SB>meter of the surface of the collector and the evaporation source is less than 0.01. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing an electrode for a lithium secondary battery.

  In recent years, the miniaturization and multi-functionalization of portable devices have progressed, and accordingly, the capacity of a battery as a power source for portable devices has been demanded. Lithium ion secondary batteries are attracting attention as secondary batteries that can satisfy this requirement.

In lithium secondary batteries currently on the market, a lithium-containing composite oxide such as LiCoO ₂ is used for the positive electrode, and carbon is used for the negative electrode. When carbon is used as the negative electrode active material, the maximum value (theoretical capacity) per volume of lithium ion absorption and release is 372 mAh / g. On the other hand, in order to increase the capacity of the lithium ion secondary battery, it has been proposed to use silicon (Si) having a theoretical capacity of 4200 mAh / g as a negative electrode active material having a theoretical capacity higher than that of carbon. Numerous materials and negative electrode structures using such materials have been studied.

  However, a material containing silicon expands and contracts greatly when inserting and extracting lithium ions. Therefore, in the negative electrode having a structure in which an active material layer using a material containing silicon is formed on a current collector such as a metal foil, the current collector hardly expands or contracts with respect to the active material layer having a large volume change. If charging / discharging is repeated, the active material layer may peel from the current collector and may not contribute to charging / discharging. Further, when such a negative electrode is used in a wound battery, the current collector extends beyond the elastic deformation region due to the expansion of the negative electrode active material, and as a result, electrode deformation such as the negative electrode plate being bent can occur. There is also sex. The separation of the active material layer and the electrode deformation are factors that deteriorate the charge / discharge cycle characteristics.

  In order to suppress the peeling of the active material layer and the deformation of the electrode due to the expansion and contraction of the negative electrode active material, a plurality of active material bodies are arranged at intervals on the surface of the sheet-like current collector. A configuration has been proposed in which a space for relaxing the expansion stress of a substance is provided.

  For example, Patent Document 1 discloses an active material layer composed of a plurality of columnar active material bodies on the surface of a current collector by depositing a negative electrode active material from an oblique direction with respect to the normal direction of the current collector (oblique deposition). Is disclosed. According to the method of Patent Document 1, it is possible to secure a gap for the active material to expand between adjacent active material bodies by a shadowing effect described later. Patent Document 1 also discloses a configuration of a roll-to-roll vapor deposition apparatus used for forming an active material body.

  Here, the reason why a plurality of active material bodies are formed by oblique deposition will be described. When the vapor deposition material is incident obliquely on the current collector having irregularities on the surface, each convex portion on the surface of the current collector forms a shadow area that is not irradiated with the vapor deposition material. For this reason, when oblique vapor deposition is performed, the vapor deposition material is easily deposited on each convex portion of the current collector, and the active material body grows in a columnar shape on each convex portion. When the active material body grows, the active material body itself also forms a shadow on the current collector, so that the surface of the current collector becomes a shadow of the active material body that grows in the form of protrusions and columns, and no vapor deposition material is deposited. A region is formed (shadowing effect). As a result, an active material layer having a structure in which a plurality of active material bodies are arranged at intervals can be obtained. Note that the interval between the active material bodies can be adjusted by the deposition direction and the size of the surface irregularities of the current collector.

  However, in the negative electrode of Patent Document 1, since a plurality of active material bodies are formed on the current collector at intervals, the contact area between each active material body and the current collector is small. In addition, since the expansion coefficient of the current collector and the active material body differs depending on the material, the adhesion strength between the active material layer made of the active material body and the current collector cannot be sufficiently secured, and the current collector is not. There is a possibility that peeling of the active material layer from the surface of the electric conductor cannot be sufficiently suppressed.

  As means for overcoming this problem, Patent Document 2 includes a material similar to the material of the active material layer between the active material layer composed of a plurality of active material bodies and the current collector, and the surface of the current collector It is proposed to provide a layer with a high coverage with respect to. According to the configuration proposed in Patent Document 2, since the adhesion between the active material layer and the current collector can be greatly improved, peeling of the active material layer can be suppressed and charge / discharge cycle characteristics can be improved.

  In addition, it is difficult to form a layer with a high coverage as described in Patent Document 2 using the same oblique deposition as the active material layer formed thereon. In oblique vapor deposition, the shadowing effect is generated by the vapor deposition direction and unevenness of the current collector surface, and the vapor deposition material is selectively deposited on the convex part of the current collector, so that the coverage on the current collector surface is sufficiently increased. It is because it is not possible.

  Therefore, Patent Document 2 proposes to perform the vapor deposition step twice by changing the vapor deposition direction as a method of manufacturing the negative electrode as described above. Specifically, after vapor deposition is performed from the normal direction of the current collector to form a high coverage layer on the current collector, a plurality of active material bodies are formed on the obtained layer by oblique vapor deposition. (Hereinafter referred to as “first method”).

As another method, it is also described that a layer with a high coverage and an active material layer are formed in the same vapor deposition apparatus. In this method, a region (active material layer forming zone) where a deposition material (for example, Si particles) is incident on the current collector surface from an oblique direction in the chamber and the Si particles are indirectly collected by collision with gas particles. The vapor deposition apparatus provided with the area | region (layer formation zone) supplied to the electrical-conductor surface is used. First, the current collector is disposed in the layer formation zone, and a layer having a high coverage is formed on the current collector surface. Thereafter, the current collector is moved to the active material layer forming zone, and a plurality of active material bodies are formed on the surface of the current collector on which the layer having a high coverage is formed (hereinafter referred to as “second method”). .
JP-A-2005-196970 International Publication No. 2007/094311 Pamphlet

  According to the first method described in Patent Document 2, in order to perform at least two vapor deposition steps having different vapor deposition directions, it is necessary to separately prepare an apparatus used in each vapor deposition step. Therefore, the manufacturing cost increases, and the manufacturing process becomes complicated, so that the manufacturing efficiency may be reduced.

  Further, according to the second method described in Patent Document 2, it is possible to accurately control the composition and thickness of a layer with a high coverage, or to form a layer that reliably covers substantially the entire surface of the current collector. It can be difficult. Therefore, there is a possibility that the adhesion between the active material layer and the current collector cannot be effectively improved.

  Thus, conventionally, an electrode for a lithium secondary battery having a structure in which the adhesion between the active material layer and the current collector is enhanced while securing a space for relaxing the expansion stress of the active material has been achieved. It was difficult to manufacture by an excellent process.

  This invention is made | formed in view of the said situation, The objective is to manufacture the electrode for lithium secondary batteries excellent in charging / discharging cycling characteristics, ensuring high productivity.

The method for producing an electrode for a lithium secondary battery of the present invention includes a chamber, a vacuum pump for exhausting the chamber, an evaporation source installed in the chamber and evaporating the first and second evaporation materials, A method for producing an electrode for a lithium secondary battery using a vacuum vapor deposition apparatus comprising a vapor deposition region formed in a region where evaporated first and second vapor deposition materials reach, wherein (A) a plurality of electrodes are formed on a surface. A current collector having a convex portion is arranged in the vapor deposition region, and the first vapor deposition material is supplied from the evaporation source onto the current collector along a direction inclined with respect to a normal direction of the current collector. Forming a first active material layer, and (B) arranging the current collector on which the first active material layer is formed in the vapor deposition region (20), and from the evaporation source, On the current collector along a direction inclined with respect to the normal direction, the first Comprising a step of forming a second active material layer by supplying the vapor deposition material. In the step (A), the product of the vacuum degree P ₁ Pascal of the chamber and the minimum distance L _{(1) min} meter between the surface of the current collector and the evaporation source is 0.01 or more, In (B), the product of the degree of vacuum P ₂ Pascal of the chamber (1) and the maximum distance L _{(2) max} meters between the surface of the current collector and the evaporation source is less than 0.01.

  According to the present invention, the same vacuum deposition apparatus is used to adjust the product of the degree of vacuum (Pa) in the chamber of the vacuum deposition apparatus and the distance (m) from the evaporation source to the current collector surface. A first active material layer having a high coverage with respect to the surface of the electric body and a second active material layer including more space for expansion of the active material can be formed. Therefore, it is possible to efficiently manufacture an electrode for a lithium secondary battery in which separation of the active material from the current collector surface and deformation of the electrode due to repeated charge and discharge are suppressed.

  Further, according to the method of the present invention, the first and second active material layers are formed in the same chamber, so that the manufacturing cost and the number of manufacturing steps can be reduced. Furthermore, since the composition and thickness of the first active material layer can be controlled separately from the second active material layer, the adhesion strength between the first and second active material layers and the current collector can be effectively increased. .

  According to the manufacturing method of the present invention, a first active material layer having a high coverage and a second active material layer having a space for expanding the active material are continuously formed using a vapor deposition apparatus for performing oblique vapor deposition. Can be formed. Therefore, an electrode for a lithium secondary battery in which separation of the active material from the current collector due to repeated charge / discharge can be efficiently produced. Moreover, since it is not necessary to use separate vapor deposition apparatuses to form the first and second active material layers, the manufacturing process and manufacturing cost can be reduced.

  By applying the present invention, an electrode in which separation of the active material due to repeated charge / discharge is suppressed can be obtained, and thus a lithium secondary battery excellent in charge / discharge cycle characteristics can be provided.

  First, the outline of the manufacturing method of the electrode for lithium secondary batteries (henceforth only an "electrode") by this invention is demonstrated.

  In the manufacturing method according to the present invention, the first active material layer and the second active material layer are formed in this order on a current collector having a plurality of convex portions on the surface using a vacuum deposition apparatus. The first and second active material layers are both formed by oblique vapor deposition. “Inclined vapor deposition” is a method of forming a vapor deposition film on a current collector by supplying a vapor deposition material to the current collector surface from a direction (vapor deposition direction) inclined with respect to the normal direction of the current collector. Say. In the manufacturing method according to the present invention, when the first and second active material layers are formed, the degree of vacuum (Pa) in the chamber of the vacuum deposition apparatus and the distance (m) from the evaporation source to the current collector surface It is characterized by adjusting the product of. Thereby, it is possible to control the incident direction of the vapor deposition particles with respect to the current collector surface.

  In the present specification, the “vacuum degree (Pa)” means a gas pressure in the chamber. The “distance from the evaporation source to the current collector surface” refers to the distance between the center of the upper surface (evaporation surface) of the vapor deposition material held by the evaporation source and the current collector surface (hereinafter referred to as “evaporation distance”). ). The “incidence direction of vapor deposition particles” refers to the traveling direction of vapor deposition particles evaporated from the vapor deposition source immediately before reaching the current collector surface. Therefore, when the vapor deposition particles reach the current collector surface without colliding with other particles, the incident direction of the vapor deposition particles is determined by the arrangement of the vapor deposition region and the evaporation source in the chamber (deposition direction). ).

  In the step of forming the first active material layer, the product of the degree of vacuum and the deposition distance described above is set to 0.01 or more. If this product is 0.01 or more, as will be described later, a part of the vapor deposition particles evaporated from the evaporation source collides with other gas molecules in the chamber and scatters before reaching the current collector surface. . Therefore, the directivity in the incident direction of the vapor deposition particles is lowered, and the vapor deposition particles are incident on the current collector surface from a wider angle regardless of the vapor deposition direction. As a result, vapor deposition particles are deposited also in a region of the current collector surface where the convex portions are not formed, so that a first active material layer having high coverage is formed on the current collector surface.

  On the other hand, in the step of forming the second active material layer, the product of the degree of vacuum and the vapor deposition distance is less than 0.01. If this product is less than 0.01, the vapor deposition particles hardly collide with other gas molecules in the chamber, and there is a high possibility of reaching the current collector surface along the vapor deposition direction. That is, vapor deposition is performed with high directivity in the incident direction of the vapor deposition particles. Therefore, the vapor deposition particles are selectively deposited on each convex portion on the surface of the current collector and grow in a columnar shape. In this specification, the columnar body formed on each convex part by diagonal vapor deposition is called an "active material body." Between adjacent active material bodies, voids for relaxing the expansion stress of the active material bodies are formed by the shadowing effect described above. In this way, a second active material layer including a plurality of active material bodies and voids formed between adjacent active material bodies is obtained.

  The product may be adjusted by changing the degree of vacuum (gas pressure) in the chamber. For example, when the first active material layer is formed, a gas such as oxygen is introduced into the chamber to increase the gas pressure in the chamber, and when the second active material layer is formed, the gas is introduced into the chamber. The amount of gas may be reduced or the introduction of gas into the chamber may be stopped to lower the gas pressure in the chamber.

  Thus, according to the present invention, the first active material layer is formed by performing vapor deposition with low directivity using the vacuum vapor deposition apparatus for performing oblique vapor deposition, and subsequently performing vapor deposition with high directivity. A second active material layer can be formed. As a result, a first active material layer with high coverage is formed on the current collector, and a second active material layer having voids for relaxing expansion stress is formed on the first active material layer. It becomes possible. Therefore, an electrode having a structure excellent in charge / discharge cycle characteristics can be efficiently manufactured without increasing manufacturing costs and manufacturing steps.

  Note that the vapor deposition material used when forming the first active material layer and the vapor deposition material used when forming the second active material layer may be the same or different. When the same vapor deposition material is used, the difference in expansion coefficient between the first and second active material layers during occlusion of lithium ions can be suppressed, so that the adhesion between these active material layers can be enhanced. It is also advantageous because the first and second active material layers can be formed using a single vapor deposition source.

  In order to increase the capacity of the lithium ion secondary battery, it is preferable that at least one of the vapor deposition materials used when forming the first and second active material layers contains silicon (Si). More preferably, each of these vapor deposition materials contains silicon. Thereby, the capacity | capacitance of a lithium ion secondary battery can be raised more effectively.

  Next, by adjusting the product of the degree of vacuum (Pa) in the chamber of the vacuum vapor deposition apparatus and the distance (m) from the evaporation source to the current collector surface, the deposition position of the vapor deposition material with respect to the current collector surface is directed. The reason why sex can be controlled will be explained. Here, a case where an Si source is used as the evaporation source and oxygen gas is introduced into the chamber in order to adjust the degree of vacuum in the chamber will be described as an example.

The radius r _{Si of} Si atoms evaporated from the evaporation source is 0.21 nm (Van der Waals radius), and the radius r _{O2 of} oxygen molecules is 0.148 nm. Note that the value of the radius r _O2 of the oxygen molecule is a value (WJ Moore; Physical Chemistry 4th Edition, Tokyo Kagaku Dojin) calculated from data such as gas viscosity using a hard sphere model. If it is assumed that there is no collision between evaporated Si atoms and the presence of gas molecules other than oxygen in the chamber is ignored, the mean free path λ _{Si of} Si atoms determined by the collision between Si atoms and oxygen molecules m)
λ _Si = 1 / [π × (r _Si + r _O2 ) ² × (1 + v _O2 ² / v _Si ² ) ^1/2 × n _O2 ] (Formula 1)
It becomes. Here, v _O2 is the average velocity of oxygen molecules (m / s), v _Si is the average velocity of Si atoms (m / s), and n _O2 is the density of oxygen molecules (number / m ³ ). v _O2 and v _Si can be calculated from the Maxwell-Boltzmann distribution law, assuming that the temperature T _{O2 of the} oxygen molecule is 300K and the temperature T _{Si of the} Si atom is 2300K.
v _O2 ≈ 450 (Formula 2)
v _Si ≒ 1300 (Formula 3)
It becomes. From the equation of state of the ideal gas, n _O2 is n _O2 = P _O2 / (k × T _O2 ) (Formula 4)
Sought by. Here, P _O2 is the oxygen partial pressure (Pa), and k is the Boltzmann constant (1.38 × 10 ²³ J / K).

When the relationship between λ _Si and P _O2 is obtained from (Equation 1) to (Equation 4) described above,
λ _Si × P _O2 ≒ 0.01 (Formula 5)
It becomes. A graph showing this relationship is shown in FIG.

When the deposition distance L (m) is equal to or greater than the mean free path λ _Si (L ≧ λ _Si ), that is, L × P _O2 ≧ 0.01 (Formula 6)
Is satisfied, the probability that Si atoms evaporated from the evaporation source collide with oxygen molecules before reaching the current collector surface becomes 1/2 or more. Therefore, among the evaporated Si atoms, the proportion of Si atoms whose traveling direction changes before entering the current collector is increased.

On the other hand, when the deposition distance L (m) is less than the mean free path λ _Si (L <λ _Si ), that is, L × P _O2 <0.01 (Formula 7)
Is satisfied, the ratio of Si atoms that reach the current collector surface without colliding with oxygen molecules among Si atoms evaporated from the evaporation source increases. Therefore, most of the evaporated Si atoms are incident on the current collector surface from a predetermined deposition direction (a direction inclined with respect to the normal direction of the current collector), and selectively on the convex portions of the current collector. accumulate.

In the relationship shown in the above (Expression 6) and (Expression 7), if the residual gas pressure other than oxygen is sufficiently small, collisions between molecules of those residual gases and Si atoms are negligible. The behavior of atoms can be regarded as almost the same regardless of the presence or absence of residual gas. Therefore, the degree of vacuum P in the chamber can be regarded as being equal to the oxygen partial pressure P _O2 (P≈P _O2 ). In this case, (Equation 6) and (Equation 7) are as follows.
L × P ≧ 0.01 (Formula 6 ′)
L × P <0.01 (Formula 7 ′)
In the present invention, since the first active material layer is formed under the condition that satisfies the above (formula 6 ′), in calculation, about 1/2 or more of the evaporated Si atoms are scattered, and the direction is different from the deposition direction. Will enter the surface of the current collector. As a result, some of the Si atoms are incident on the current collector surface from an angle at which no shadowing effect occurs, and are also deposited in a region of the current collector surface where no protrusion is formed. In this way, a first active material layer having a large contact area with the current collector surface and excellent adhesion can be obtained. In addition, since the Si atoms that have reached the current collector surface without scattering are selectively deposited on the convex portions of the current collector due to the shadowing effect, in many cases, the thickness of the first active material layer is: It becomes larger on the convex portion of the current collector surface than on the region where the convex portion is not formed. Preferably, the first active material layer is formed under the condition that the product of the deposition distance L and the degree of vacuum in the chamber is 0.02 or more. Thereby, more Si atoms are scattered and the traveling direction thereof is changed, so that the first active material layer having high adhesion can be more reliably formed. In addition, since the thickness difference between the portion of the first active material layer located on the convex portion of the current collector surface and the portion located on the region where the convex portion is not formed can be suppressed, Adhesiveness with a current collector can be enhanced while suppressing the maximum thickness of one active material layer.

  Further, since the second active material layer is formed under the condition satisfying the above (formula 7 ′), in calculation, about 1/2 or more of the evaporated Si atoms are in the first active material along the predetermined deposition direction. Incident on the surface of the layer. Here, the first active material layer has unevenness due to the surface unevenness of the current collector. As described above, when the first active material layer is thick on the convex portion of the current collector, the first active material layer has irregularities having a level difference larger than the surface irregularity of the current collector. Therefore, Si atoms incident on the current collector surface from the vapor deposition direction are selectively deposited on the convex portions of the current collector through the first active material layer due to the shadowing effect. As a result, a plurality of columnar active material bodies are formed on the first active material layer. Preferably, the second active material layer is formed under the condition that the product of the deposition distance L and the degree of vacuum in the chamber is less than 0.005. Thereby, the expansion space of an active material body can be ensured more reliably.

  In the above description, the case where oxygen gas is introduced into the chamber has been described as an example, but substantially the same even when another gas (for example, a gas that does not react with a deposition material such as argon) is introduced instead of the oxygen gas. Deposition conditions are calculated. Therefore, the range of the product of the degree of vacuum (Pa) and the deposition distance (m) when forming the first and second active material layers is constant regardless of the type of gas introduced into the chamber. Similarly, the product range is constant even when a vapor deposition material other than Si is used.

(Embodiment)
Hereinafter, embodiments will be described by taking as an example a method for producing a negative electrode for a lithium secondary battery. In this embodiment, using a roll-to-roll vacuum deposition apparatus, a first active material layer having a high covering property on a current collector and a second active material layer composed of a plurality of active material bodies are arranged in this order. Form.

  First, an example of a vacuum deposition apparatus used in the present embodiment will be described with reference to the drawings.

<Configuration of vacuum evaporation system>
FIG. 2 is a cross-sectional view schematically showing a vapor deposition apparatus according to an embodiment of the present invention.

  The vapor deposition apparatus 100 is provided outside the chamber 1, the exhaust pump 2 for exhausting the chamber 1, and the gas introduction for introducing a gas such as oxygen gas into the chamber 1 from the outside of the chamber 1 (not shown). A tube. Inside the chamber 1, there are an evaporation source 3 for evaporating the vapor deposition raw material 12, a transport unit for transporting a sheet-like substrate (current collector) 4, and the current collector 4 and the evaporation source 3 to be transported. There are provided masks 10 a and 10 b which are arranged in between and shield the vapor deposition material 12 evaporated from the evaporation source 3, and a gas nozzle 11 which is connected to the gas introduction pipe and supplies gas to the chamber 1.

  The evaporation source 3 includes, for example, a container such as a crucible for storing the vapor deposition material 12 and a heating device (not shown) for evaporating the vapor deposition material 12, and the vapor deposition material 12 and the container are appropriately detachable. Yes. As the heating device, for example, a resistance heating device, an induction heating device, an electron beam heating device, or the like can be used. When performing vapor deposition, the vapor deposition raw material 12 accommodated in the crucible is heated by the heating device, evaporates from the upper surface (evaporation source) 12 s, and is supplied to the surface of the current collector 4.

  The transport unit includes first and second rolls 5 and 9 that can wind and hold the current collector 4 and a guide unit that guides the current collector 4. The guide unit includes transport rollers 6 a and 6 b and first and second can rolls 7 and 8, thereby defining a transport path of the current collector 4.

  In the present embodiment, any one of the first and second rolls 5 and 9 feeds out the current collector 4, and the guide unit guides the fed current collector 4 along the transport path, The other of the second rolls 5 and 9 winds up the current collector 4. The wound current collector 4 is further fed out by the other roll as necessary, and is transported in the reverse direction along the transport path. Thus, the 1st and 2nd rolls 5 and 9 in this embodiment can function as a winding roll and a winding roll depending on a conveyance direction. Moreover, since the frequency | count that the electrical power collector 4 passes the vapor deposition area | region 20 can be adjusted by repeating inversion of a conveyance direction, the vapor deposition process of a desired frequency | count can be implemented continuously.

  The first scan roll 7 and the second scan roll 8 are arranged so that the surface of the current collector 4 conveyed between these rolls 7 and 8 faces the evaporation surface 12s. Therefore, the area 20 excluding the area located between the first scan roll 7 and the second scan roll 8 in the transport path of the current collector 4 and shielded by the masks 10a and 10b is an “evaporation area”. It becomes. The gas nozzle 11 is disposed so as to supply gas to the surface of the current collector 4 that travels in the vapor deposition region 20.

In the present embodiment, the vapor deposition material evaporated from the evaporation surface 12s is incident on the current collector 4 from a direction (vapor deposition direction) inclined with respect to the normal direction of the current collector 4 traveling in the vapor deposition region 20. First and second scan rolls 7 and 8 and masks 10a and 10b are arranged. In this specification, an angle formed by a straight line connecting the current collector 4 traveling in the vapor deposition region 20 and the evaporation surface 12 s and the normal direction N of the current collector 4 at that time is referred to as a “vapor deposition angle”. Therefore, in the illustrated example, the vapor deposition angle is minimized at the end 20x on the first scan roll side of the vapor deposition region 20, and the vapor deposition angle is maximized at the end 20y on the second scan roll side. In this specification, the minimum value of the vapor deposition angle in the vapor deposition region 20 is referred to as the minimum vapor deposition angle θ _min , and the maximum value of the vapor deposition angle is referred to as the maximum vapor deposition angle θ _max . Here, the minimum deposition angle θ _min in the deposition region 20 is set to 20 ° or more, and the maximum deposition angle θ _{max is set} to 85 ° or less. In addition, it is preferable that minimum vapor deposition angle (theta) _min is 45 degrees or more, More preferably, it is 60 degrees or more. Thereby, the space | gap required for expansion stress relaxation of the deposited active material is securable.

  The first and second rolls 5 and 9, the transport rollers 6a and 6b, and the first and second scan rolls 7 and 8 have, for example, a cylindrical shape having a length of 600 mm, and the length direction thereof (that is, transport) (The width direction of the current collector 4) is arranged in the chamber so as to be parallel to each other. In FIG. 2, only a cross section parallel to these cylindrical bottom surfaces is shown. The evaporation source 3 may be configured such that, for example, the evaporation surface 12s of the vapor deposition raw material 12 has a sufficient length (for example, 600 mm or more) parallel to the width direction of the current collector 4 conveyed by the conveyance unit. Good. Thereby, substantially uniform vapor deposition can be performed in the width direction of the current collector 4. The evaporation source 3 may be composed of a plurality of crucibles arranged along the width direction of the current collector 4 to be conveyed. Further, the gas nozzle 11 is also a pipe extending along the width direction (direction perpendicular to the cross section shown in FIG. 2) of the current collector 4 to be conveyed, for jetting gas to the vapor deposition region 20 on the side surface thereof. A plurality of exit ports may be provided.

<Method for producing electrode>
Hereinafter, an example of a method for producing the electrode of the present embodiment will be described with reference to FIGS. 3A to 3E and FIG. 2 described above. 3A to 3E are schematic process cross-sectional views for explaining a method for manufacturing an electrode according to this embodiment.

  First, as shown in FIG. 3A, the current collector 4 having a plurality of convex portions 42 on the surface is formed by forming a regular uneven pattern on the surface of the metal foil by the following method. On a copper foil using a negative mask on which a negative photoresist is applied on a rolled copper foil (made of Japanese foil) having a thickness of 18 μm and a rhombus pattern having a diagonal length of 10 μm × 20 μm is arranged. The resist film was exposed and developed. Copper particles were deposited in the formed grooves by an electrolytic method. Thereafter, the resist was removed to obtain a current collector having a recess and a protruding region (10 × 20 μm rhombus) partitioned by the recess. As the metal foil, for example, a copper foil having a roughened surface may be used, and a commercially available metal foil (uneven foil) having a large surface roughness can also be used.

  Next, the current collector 4 is wound around the first roll 5 of the vacuum vapor deposition apparatus 100 shown in FIG. Further, a Si source is used as the evaporation source 3. Further, the gas nozzle 11 is connected to an oxygen cylinder (not shown) disposed outside the chamber 1 through a mass flow meter.

Thereafter, the first active material layer is formed. First, the chamber 1 is evacuated by the vacuum pump 2. The evaporation source is irradiated with an electron beam, and the electron beam power is set to a predetermined value. Oxygen gas is introduced into the chamber ₁ to adjust the inside of the chamber 1 to a predetermined degree of vacuum P ₁ . Vacuum P _1, the distance between the arranged the collector 4 of the surface deposition region 20 and the evaporation surface 12s (the deposition distance) When L _1, with a range satisfying P ₁ × L ₁ ≧ 0.01 Selected.

The degree of vacuum P ₁ of the chamber ₁ is measured using a vacuum gauge (not shown) installed inside the chamber 1. In addition, since the above relationship is obtained in consideration of the mean free path of Si atoms, the “vacuum degree P ₁ ” in the above relationship is precisely between the evaporation surface 12 s in the chamber 1 and the vapor deposition region 20. It is the degree of vacuum (gas pressure) measured by arranging a vacuum gauge. However, when the gas pressure in the chamber 1 is sufficiently low (for example, 10 ⁻¹ Pa or less), the gas pressure inside the chamber 1 becomes substantially uniform, so that the measurement value hardly changes depending on the position of the vacuum gauge in the chamber 1. it is conceivable that. Therefore, the position of the vacuum gauge is not particularly limited. For example, the vacuum gauge P ₁ in the chamber 1 may be measured by installing a vacuum gauge on the side wall of the chamber 1.

In the present embodiment, the vapor deposition distance L ₁ connects a point on the surface of the current collector 4 disposed in the vapor deposition region 20 and the center of the evaporation surface 12 s in a cross section perpendicular to the width direction of the current collector 4. Refers to the length of the line segment. Therefore, the deposition distance L ₁ varies depending on the position in the deposition region 20. It is in order to satisfy the relationship described above regardless of the position in the deposition region 20, the minimum value of the deposition distance L ₁ at (minimum evaporation distance) L _{(1) min} and the product of the degree of vacuum P ₁ is 0.01 or more (P ₁ × L _{(1) min} ≧ 0.01). In the illustrated example, the distance L _min between the portion 20x of the vapor deposition region 20 closest to the evaporation surface 12s and the evaporation surface 12s is the minimum vapor deposition distance L _{(1) min} .

  Subsequently, the current collector 4 is unwound from the first roll 5 and guided to the vapor deposition region 20 by the transport roller 6a and the first scan roll 10a. The Si atoms evaporated from the evaporation source 3 are supplied to the current collector 4 traveling in the vapor deposition region 20.

  At this time, as shown in FIG. 3B, a part of Si atoms supplied from the direction D inclined with respect to the normal direction of the current collector 4 reaches the surface of the current collector 4. It collides with oxygen gas and other Si atoms, and its traveling direction changes. Accordingly, some of the Si atoms enter the current collector 4 from a direction different from the vapor deposition direction D.

  As a result, as shown in FIG. 3C, some Si atoms whose traveling direction has changed are incident not only on the convex portions 42 of the current collector 4 but also on the regions where the convex portions 42 are not formed. Reacts with oxygen to form silicon oxide (reactive vapor deposition). On the other hand, Si atoms that have reached the current collector 4 along the vapor deposition direction D are incident only on the convex portions 42 of the current collector 4 due to the shadowing effect, and react with oxygen to form silicon oxide. In this way, the first active material layer 45 made of silicon oxide is obtained. In the illustrated example, the portion 45a located on the convex portion 42 of the current collector 4 in the obtained first active material layer 45 is thicker than the portion 45b located on the region where the convex portion 42 is not formed. Become.

  The current collector 4 after the first active material layer 45 is formed is transported to the second roll 9 by the second scan roll 8 and the transport roller 6 b and is taken up by the second roll 9.

Next, a second active material layer is formed. First, it suppresses the flow rate of oxygen gas to be introduced into the chamber 1, or by stopping the introduction of oxygen gas, to adjust the chamber 1 to a predetermined vacuum level P _2. Vacuum P _2, the distance between the arranged the collector 4 of the surface deposition region 20 and the evaporation surface 12s (the deposition distance) When L _2, in a range satisfying P ₁ × L ₂ <0.01 Selected. In this embodiment, the vapor deposition distance L ₂ when forming the second active material layer is the same as the vapor deposition distance L ₁ when forming the first active material layer. To satisfy the relationships described above regardless of the position in the deposition region 20, the maximum value (maximum deposition distance) of the deposition distance L ₂ L ₍₂₎ the product of the _max and the degree of vacuum P ₂ is any smaller than 0.01 (P ₂ × L _{(2) max} <0.01). In the illustrated example, the distance L _max between the evaporation surface 12s and the portion 20y farthest from the evaporation surface 12s in the evaporation region 20 is the minimum evaporation distance L _{(2) max} .

  Next, the current collector 4 is unwound from the second roll 9 and guided to the vapor deposition region 20 by the transport roller 6b and the second scan roll 10b. The Si atoms evaporated from the evaporation source 3 are supplied to the current collector 4 traveling in the vapor deposition region 20.

At this time, as shown in FIG. 3D, Si atoms are supplied from the direction D inclined with respect to the normal direction of the current collector 4. As described above, under the condition of P ₁ × L ₂ <0.01, the probability that the Si atoms collide with the oxygen gas before reaching the surface of the current collector 4 is low. Along the deposition direction D, the first active material layer 45 selectively enters the portion 45 a located on the convex portion 42 of the current collector 4.

  As a result, as shown in FIG. 3E, an active material body 47 made of silicon or silicon oxide is formed on each convex portion 42 of the current collector 4 via the first active material layer 45. . Each active material body 47 grows in a direction inclined with respect to the normal line direction of the current collector 4 due to the vapor deposition direction D, whereby the second active material layer 48 composed of a plurality of active material bodies 47. Is obtained. A space 47 ′ for expanding the active material body 47 is formed between the adjacent active material bodies 47.

  The current collector 4 after the second active material layer 48 is formed is transported by the first scan roll 10 a and the transport roller 6 a and wound up by the first roll 5. In this way, the electrode 200 having the first and second active material layers 45 and 48 on the current collector 4 is obtained.

  According to the above method, the first active material layer 45 and the second active material layer 48 can be formed using the same vapor deposition region 20. Therefore, the electrode 200 can be efficiently produced using a simpler and smaller vapor deposition apparatus, which is advantageous.

  The first active material layer 45 is preferably a continuous film (so-called solid film) that covers substantially the entire surface of the current collector 4. This is because the coverage of the surface of the current collector 4 is increased, and the adhesion between the current collector 4 and the first active material layer 45 can be further increased.

The thickness H ₁ of the first active material layer 45 is preferably not less than 0.1 μm and not more than 10 μm, for example. If it is 0.1 micrometer or more, peeling from the electrical power collector 4 of an active material can be suppressed effectively. On the other hand, if the thickness exceeds 10 μm, the current collector 4 may be deformed by the expansion of the first active material layer 45. The “thickness H _{1 of} the first active material layer 45” here is from the upper surface or vertex of the convex portion 42 of the current collector 4 to the upper surface of the first active material layer 45 as shown in FIG. Of the current collector 4 along the normal direction N.

The thickness H ₂ of the second active material layer 48 is preferably not less than 5 μm and not more than 20 μm, for example. If it is 5 μm or more, a sufficient capacity can be secured. On the other hand, if the thickness H ₂ exceeds 20 μm, the aspect ratio of the active material body 47 becomes large, and the active material body 47 is likely to be broken or the like, which may cause deterioration of characteristics. . The “thickness H _{2 of} the second active material layer 47” here is the current collector 4 from the upper surface of the first active material layer 45 to the upper surface of the active material body 47 as shown in FIG. The distance along the normal direction N of

  In the above method, the current collector 4 passes through the vapor deposition region 20 twice, but may pass through the vapor deposition region 20 three times or more by reversing the transport direction of the current collector 4. For example, in the second active material layer forming step, the vacuum evaporation apparatus 100 is operated so that the current collector 4 passes through the vapor deposition region 20 twice or more to form a second active material layer having a laminated structure. Good. Alternatively, a plurality of vapor deposition regions having different vapor deposition directions may be provided in the chamber 1. In this case, the second active material layer composed of a plurality of active material bodies grown in a zigzag shape can be formed by performing a plurality of stages of oblique vapor deposition while switching the vapor deposition direction. Specific vapor deposition conditions for forming such an active material body are described in, for example, pamphlet of International Publication No. 2007/086411 by the present applicant.

Further, the degree of vacuum P ₁ and P ₂ is controlled by adjusting the flow rate of oxygen gas introduced into the chamber 1, but instead of introducing argon gas that does not react with the vapor deposition material (for example, Si). Good. Alternatively, both oxygen gas and argon gas may be introduced. The vapor deposition material 12 is not limited to Si, and instead, elements such as Ge and Sn that occlude and release lithium may be used. In the above method, the same vapor deposition material (Si) 12 is used to form the first and second active material layers 45 and 48, but different vapor deposition materials may be used.

Further, in the above method, since the first active material layer 45 and the second active material layer 48 are formed using the same vapor deposition region 20, when the first and second active material layers 45, 48 are formed. The vapor deposition distances L ₁ and L ₂ are the same, but they may be different from each other. For example, the deposition distances L ₁ and L ₂ may be adjusted by changing the position of the deposition source 3.

  The configuration of the vacuum deposition apparatus used in the present embodiment is not limited to the configuration of the vacuum deposition apparatus 100 described above, but is preferably a deposition apparatus capable of continuous processing such as a roll-to-roll system from the viewpoint of mass productivity.

  Further, the cross-sectional shapes of the first active material layer 45 and the second active material layer 48 are not limited to the shapes illustrated in FIG. The first active material layer 45 has a higher coverage than at least the second active material layer 48, and the second active material layer 48 has at least more voids than the first active material layer 45 to relieve expansion stress. If it has, the effect by this invention can be acquired.

The electrode produced by the method of the present embodiment can be applied to both a negative electrode and a positive electrode of a lithium secondary battery, but is preferably used as a negative electrode for a lithium secondary battery. In this case, lithium-containing transition metal oxides such as lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), and lithium manganate (LiMn ₂ O ₄ ) can be used as the positive electrode active material.

(Examples and Comparative Examples)
Since the electrodes of the examples and comparative examples and the electrodes using the electrodes were manufactured and the characteristics were evaluated, the methods and results will be described.

<Method for producing electrode>
(I) Example First, copper plating was performed so that a rhombus pattern was placed on a rolled copper foil (manufactured by Japanese foil) having a thickness of 18 μm, thereby obtaining a current collector used in the example. 4A and 4B are a schematic cross-sectional view and a top view, respectively, of the current collector in the example. As shown in the drawing, each convex portion 42 has a rectangular column shape (height: 10 μm) whose upper surface is a rhombus (diagonal length: 10 μm × 20 μm). Further, assuming that the direction along the shorter diagonal of the rhombus is the “X direction” and the direction along the longer diagonal is the “Y direction”, the rows in which the convex portions 42 are arranged at a pitch P _X of 22 μm in the X direction. And an example in which this row was translated in the X direction by 1/2 of the pitch P _X were alternately arranged at a pitch P _Y of 55 μm along the Y direction.

Next, using the vacuum vapor deposition apparatus 100 shown in FIG. 2, the first and second active material layers were formed by the same method as described above with reference to FIGS. As an evaporation source, simple silicon having a purity of 99.9999% (manufactured by Kojundo Chemical Laboratory Co., Ltd.) was used. Further, the vapor deposition angle θ is 70 °, the minimum value L _min of the distance between the evaporation surface and the current collector disposed in the vapor deposition region (vapor deposition distance) is 0.7 m, and the maximum value L _max is 0.9 m. The vapor deposition region and the evaporation source were arranged so as to be.

Subsequently, oxygen gas was introduced into the chamber at a flow rate of 215 sccm, and the degree of vacuum P ₁ in the chamber was set to 3 × 10 ⁻² . In this state, the Si particles evaporated by the evaporation source are supplied to the surface of the current collector that runs in the vapor deposition region, thereby forming a compound (silicon oxide) containing silicon and oxygen on the current collector. A first active material layer was formed (first active material layer forming step). The electron beam power applied to the evaporation source was 11 kW, and the deposition time was 8 minutes.

Thereafter, the introduction of oxygen gas into the chamber was stopped, and the degree of vacuum P ₂ in the chamber was set to 3 × 10 ⁻³ . In this state, the second active material layer made of silicon was formed on the first active material layer by supplying Si particles evaporated by the evaporation source to the surface of the current collector running in the vapor deposition region ( Second active material layer forming step). The electron beam power applied to the evaporation source was 11 kW, and the deposition time was 16 minutes.

  Thus, the electrode of the example was obtained. The obtained electrode was embedded and polished in an epoxy resin, and the cross section was observed with a scanning electron microscope (SEM).

  FIG. 5 is a diagram showing a cross-sectional SEM image of the electrode of the example. From FIG. 5, the first active material layer 45 is a continuous film that covers the entire surface of the current collector 4, and the second active material layer 48 is a plurality of layers arranged on the first active material layer 45 at intervals. It can be seen that it is composed of the active material body 47. The thickness of the first active material layer 45 was 6 μm, and the thickness of the second active material layer 48 was 11 μm.

(Ii) Comparative Example 1
An electrode of Comparative Example 1 was produced by the same method and conditions as in the Examples, except that the first active material layer was not formed. The cross section of the obtained electrode was observed by the same method as in the example.

  6 is a cross-sectional SEM image of the electrode of Comparative Example 1. FIG. As shown in FIG. 6, the electrode of Comparative Example 1 had the current collector 4 and a plurality of active material bodies 52 arranged on each convex portion 42 of the current collector 4. Moreover, it was confirmed that Si atoms were not deposited between the adjacent convex parts 42 among the surfaces of the current collector 4. The thickness of the second active material layer 53 composed of the plurality of active material bodies 52 was 12 μm.

(Iii) Comparative Example 2
The electrode of Comparative Example 2 was produced by forming the first and second active material layers on the current collector in the same manner as in the example using the same current collector as in the example. However, in Comparative Example 2, the oxygen flow rate when forming the first active material layer was 43 sccm, and the degree of vacuum P ₁ was 7 × 10 ⁻³ Pa. Therefore, the product of the degree of vacuum and the deposition distance when forming the first active material layer was less than 0.01. The other conditions for forming the first active material layer and the conditions for forming the second active material layer were the same as those in the example. The cross section of the obtained electrode was observed by the same method as in the example.

  FIG. 7 is a schematic cross-sectional view of the electrode of Comparative Example 2. As shown in FIG. 7, the first active material layer 56 is composed of active material bodies 55 disposed on the respective convex portions 42 of the current collector 4, and the second active material layer 58 is composed of each active material body 55. It was found to be composed of the active material member 57 arranged on the top. In the step of forming the first active material layer 56, since the product is less than 0.01, collision between Si atoms and oxygen hardly occurs, and as a result, a convex portion of the surface of the current collector 4 is caused by the shadowing effect. It is considered that Si atoms were not deposited on the region where 42 was not formed. The thickness of the first active material layer 56 of Comparative Example 2 was 5 μm, and the thickness of the second active material layer 58 was 10 μm.

  Table 1 summarizes the manufacturing conditions of the electrodes of the examples and comparative examples described above and the measurement results of the thickness of each active material layer.

<Production of sample battery>
The electrodes of Examples and Comparative Examples 1 and 2 obtained by the above method were punched into a circle having a diameter of 12.5 mm to form an electrode for a sample battery. Next, each of the obtained sample battery electrodes was used to produce a sample battery.

  FIG. 8 is a cross-sectional view schematically showing a sample battery manufactured using the electrodes of Examples and Comparative Examples 1 and 2. The sample battery includes an electrode 31 for the sample battery described above, a counter electrode (metal lithium) 33 facing the electrode 31, and a separator 32 that is interposed between the counter electrode 33 and the electrode 31 and contains an electrolyte that conducts lithium ions. Have A metal disc 34 for collecting current from the electrode 31 is provided on the surface of the electrode 31 that is not opposed to the counter electrode 33, and between the metal disc 34 and the bottom surface of the coin-type battery case 36. Is provided with a disc spring 35 for pressurizing the electrode 31. The electrode 31 and the counter electrode 33 are housed in a coin-type battery case 36 together with the separator 33 and the electrolyte, and are sealed by a sealing plate 37 having a gasket 38. Further, the battery case 36 and the sealing plate 35 are electrically connected to the electrode 31 and the counter electrode 33, respectively, and also function as positive and negative terminals.

In this example and comparative example, a lithium metal foil having a thickness of 300 μm (made by Honjo Chemical) was used as the counter electrode 33, and a polyethylene microporous film (made by Asahi Kasei) having a thickness of 20 μm was used as the separator 32. A coin-type sample battery (diameter: 20 mm, thickness 1.6 mm) was produced. As the electrolytic solution, a solution obtained by dissolving 1 mol / L of lithium hexafluorophosphate (LiPF ₆ ) in a 1: 1 (volume ratio) mixed solvent of ethylene carbonate and diethyl carbonate was used. The impregnation with the electrolytic solution was performed by immersing the separator 32 and the electrode 31 in the electrolytic solution for 10 seconds.

<Evaluation method and result of sample battery>
Then, the charge / discharge cycle test of the sample battery of an Example, the comparative example 1, and the comparative example 2 was done.

In the charge / discharge cycle test, each sample battery is stored in a constant temperature bath at 20 ° C., charged at a constant current of 1 mA / cm ² until the battery voltage reaches 1.5 V, and then 1 mA / cm until 0.0 V. ^The cycle of discharging at a constant current of ² was repeated 10 times. The ratio of the discharge capacity at the 10th cycle with respect to the discharge capacity at the 1st cycle was determined and used as “capacity maintenance ratio (%)”. After the charge / discharge cycle test, each sample battery was disassembled and the state of the active material of the electrode was observed.

  Table 2 shows the measurement results of the capacity retention ratio and the state of the active material after the charge / discharge cycle test.

  From the results shown in Table 2, it was found that the battery sample of the example maintained a capacity of 90% or more even after 10 cycles and had excellent charge / discharge cycle characteristics. In the electrode of the example, it is considered that the adhesion between the second active material layer and the current collector is enhanced by the first active material layer, and as a result, the active material is effectively prevented from falling off the current collector. It is done. More specifically, since the first active material layer has a high coverage with respect to the current collector and the contact area with the current collector is large, the adhesion strength between the first active material layer and the current collector is large. . In addition, since the first and second active material layers are formed using the same vapor deposition material (Si), the difference in the expansion coefficient associated with the occlusion of lithium ions in these active material layers is kept small. Therefore, even if charging / discharging is repeated, each active material body which comprises a 2nd active material layer does not fall easily from a 1st active material layer.

  On the other hand, it turned out that the capacity | capacitance of the battery sample of the comparative example 1 and the comparative example 2 falls significantly by a charging / discharging cycle. In Comparative Example 1, since the contact area between each active material body constituting the second active material layer and the current collector is small and the expansion rates of the active material body and the current collector are greatly different, charging / discharging It is considered that the active material body is easily detached from the current collector by repeating the above. Further, in Comparative Example 2, it is considered that the first active material layer having sufficient coverage was not formed, and as a result, the effect of suppressing the falling off of the active material was hardly obtained.

  In addition, in the battery sample used for the evaluation of the cycle characteristics, each electrode of the example and the comparative example is a positive electrode, and metallic lithium is a negative electrode, but a battery sample having each electrode of the example and the comparative example as a negative electrode is prepared. Even if the charge test is performed, the same result as above can be obtained.

  The method for producing an electrode for a lithium secondary battery according to the present invention is applied to an electrode using an active material having a large volume change due to insertion and extraction of lithium ions, for example, a negative electrode for a lithium secondary battery using silicon or silicon oxide as an active material. When applied, it is advantageous because the charge / discharge cycle characteristics can be greatly improved while securing a high capacity.

  The present invention can be applied to various lithium secondary batteries such as a coin type, a cylindrical type, a flat type, and a square type. Since these lithium secondary batteries have excellent charge / discharge cycle characteristics, they can be widely used in portable information terminals such as PCs, mobile phones, and PDAs, and audiovisual equipment such as video recorders and memory audio players.

It is a graph which shows the relationship between the oxygen partial pressure in a chamber, and the mean free path of a silicon atom. It is typical sectional drawing which shows an example of the vacuum evaporation system used by embodiment of this invention. (A) to (e) are process cross-sectional views for explaining an electrode manufacturing method according to an embodiment of the present invention. (A) And (b) is sectional drawing and a top view of a current collector used in an example, respectively. It is a figure which shows the scanning electron microscope image of the electrode cross section of an Example. 6 is a view showing a scanning electron microscope image of an electrode cross section of Comparative Example 1. FIG. 6 is a cross-sectional view schematically showing an electrode of Comparative Example 2. FIG. It is sectional drawing which shows typically the structure of the sample battery produced using the electrode of an Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chamber 2 Vacuum pump 3 Evaporation source 4 Current collector 5 1st roll 6a, 6b Conveyance roll 7 1st can roll 8 2nd can roll 9 2nd roll 10a, 10b Mask 11 Gas nozzle 12 Vapor deposition material 12s Evaporation surface 31 Sample battery electrode 32 Separator 33 Counter electrode (lithium metal foil)
34 Metal Disc 35 Disc Spring 36 Coin Type Battery Case 37 Sealing Plate 38 Gasket 42 Protrusion 45 First Active Material Layer 47 Active Material Body 48 Second Active Material Layer 100 Vacuum Deposition Device 200 Electrode

Claims (9)

A chamber, a vacuum pump for evacuating the chamber, an evaporation source installed in the chamber for evaporating the first and second evaporation materials, and an area where the evaporated first and second evaporation materials reach A method for producing an electrode for a lithium secondary battery using a vacuum vapor deposition device comprising a vapor deposition region formed on
(A) A current collector having a plurality of convex portions on the surface is disposed in the vapor deposition region, and is disposed on the current collector along a direction inclined with respect to a normal direction of the current collector from the evaporation source. Supplying the first vapor deposition material to form a first active material layer;
(B) A current collector on which the first active material layer is formed is disposed in the vapor deposition region, and the current collector is along a direction inclined from the evaporation source with respect to a normal direction of the current collector. Supplying the second vapor deposition material thereon to form a second active material layer,
In the step (A), the product of the vacuum degree P ₁ Pascal of the chamber and the minimum distance L _{(1) min} meter between the surface of the current collector and the evaporation source is 0.01 or more,
In the step (B), the product of the vacuum degree P ₂ Pascal of the chamber and the maximum distance L _{(2) max} meter between the current collector surface and the evaporation source is less than 0.01 lithium secondary Manufacturing method of battery electrode.   In the step (B), the second vapor deposition material is deposited on the respective convex portions of the current collector through the first active material layer, so that an interval is formed on the first active material layer. 2. The method for producing an electrode for a lithium secondary battery according to claim 1, which is a step of forming a plurality of arranged active material bodies and thereby forming a second active material layer composed of the plurality of active material bodies. The method for manufacturing an electrode for a lithium secondary battery according to claim 1, wherein P ₁ is larger than P ₂ .   The method for manufacturing an electrode for a lithium secondary battery according to claim 1, wherein at least one of the first active material layer and the second active material layer contains silicon.   The method for manufacturing an electrode for a lithium secondary battery according to claim 1, wherein the first vapor deposition material and the second vapor deposition material contain silicon.   The method for manufacturing an electrode for a lithium secondary battery according to claim 1, wherein the first vapor deposition material and the second vapor deposition material are the same.   The method for producing an electrode for a lithium secondary battery according to claim 1, wherein the step (A) includes a step of introducing oxygen into the chamber.   2. The method of manufacturing an electrode for a lithium secondary battery according to claim 1, wherein the step (A) includes a step of introducing a gas that does not react with the first vapor deposition material into the vacuum chamber.   The method for producing an electrode for a lithium secondary battery according to claim 8, wherein the gas contains argon.

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