JP2013214456A - Power storage device, secondary battery, power storage device manufacturing method, and power storage device electrode manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device and a secondary battery which can improve current collection efficiency and can also improve output density and energy density.SOLUTION: A secondary battery electrode 10 included in the electrode body of a power storage device (secondary battery) includes an active material layer 12 having a coating of active material applied to at least one face of a metal-made collector plate 11. The collector plate 11 includes an active material non-coated portion 13 on one end side in the breadth direction thereof, which is formed along the whole region of the active material layer 12. The active material layer 12 is provided with a metal mesh 14 smaller in thickness than the active material layer 12 itself, part of which at least is disposed inside the active material layer 12. The metal mesh 14 has a plurality of polygonal openings 14a formed therein, in one of which at least the line width of corner portions is narrower than twice the line width of linear portions of the opening 14a.

Description

  The present invention relates to a power storage device, a secondary battery, a method for manufacturing a power storage device, and a method for manufacturing a power storage device electrode.

  Secondary batteries are widely used as a power source because they can be recharged and used repeatedly. In recent years, there has been a demand for reduction in the use of fossil fuels (restriction of carbon dioxide emissions). Secondary batteries used for main and auxiliary power sources such as electric vehicles and hybrid vehicles are charged and discharged with large currents and secondary batteries. Increased capacity of batteries is required.

  2. Description of the Related Art Secondary batteries such as nickel metal hydride secondary batteries and lithium ion secondary batteries use an active material coated (supported) on a current collector plate made of metal foil as an electrode. Further, by increasing the amount of the active material applied to the current collector plate, the output of the secondary battery (a value obtained by multiplying the discharge current by the discharge voltage) can be increased. As a configuration for increasing the amount of active material applied (supported) on the current collector plate, it has been proposed to apply the active material to a so-called punching metal in which a large number of holes are formed in a metal foil. Further, it has been proposed to use an expanded metal for the current collector plate as a hydrogen storage electrode (see Patent Document 1). Expanded metal is a thin flat plate provided with a large number of cuts that reach the back in a line parallel to each other, and the thin flat plate is expanded in a direction perpendicular to the cut direction to form a large number of rhomboid openings. As a result, as shown in FIG. 13, in the expanded metal 51, the line portion 53 surrounding one opening 52 has a line width W1 corresponding to the corner of the rhombus that is equal to the line width W2 of the other portion. Doubled. In Patent Document 1, a hydrogen storage electrode manufactured by press-bonding a sheet obtained by kneading a hydrogen storage alloy powder together with a binder to a metal current collector plate having a rhomboid opening and made of expanded metal is disclosed. Proposed.

Japanese Patent No. 2529023

  In general, an electrode is formed with an active material non-applied portion (tab portion) that joins a current collecting terminal to one end side in the width direction of the current collector plate, and the active material is applied to a region excluding the active material non-applied portion. Thus, an active material layer is formed. In the secondary battery using the electrode having such a configuration, electricity generated in the active material layer is output through the current collecting terminal. However, since the conductivity of the active material is small compared to the conductivity of the metal foil, when punching metal or metal mesh is used as the current collector plate, the area of the large conductivity portion is reduced, and the secondary battery discharges. Sometimes, current cannot flow in a state where the current density is large toward the active material non-coated portion, and the current collection efficiency is deteriorated. As a result, the output density of the secondary battery, that is, the output per unit volume or the unit weight of the secondary battery is reduced.

  In the expanded metal, methods for adjusting the aperture ratio of the opening include changing the line width and changing the pitch. However, in order to change the pitch with expanded metal, it is necessary to make a new blade mold, which requires a great deal of cost. In addition, the pitch that can be processed with expanded metal is limited, and it is difficult to create a fine mesh. Furthermore, in the expanded metal, the shape of the opening is limited to a rhombus, and the line width W1 of the portion corresponding to each corner is twice the line width W2 of the other portion, so the opening ratio is reduced accordingly. In addition, it is difficult for the punching metal to adjust the aperture ratio and simultaneously adjust both the aperture ratio and the size of the opening.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a power storage device and a secondary battery in which current collection efficiency can be improved and both output density and energy density can be improved. It is to provide. Another object is to provide a method for manufacturing the power storage device and a method for manufacturing an electrode for the power storage device.

In order to achieve the above object, an invention according to claim 1 is a power storage device including an electrode body having an electrode having an active material layer in which an active material is coated on a surface of a metal current collector plate. And
A metal mesh having a thickness smaller than that of the active material layer is provided in a state where at least a part is disposed in the active material layer, and the metal mesh has a plurality of polygonal openings, and at least, The line width of each corner portion of one opening is smaller than twice the line width of the straight portion of the opening. Here, “a state in which at least a part is disposed in the active material layer” means a state in which one side of the metal mesh is exposed from the active material layer, or a state in which the entire metal mesh is embedded in the active material layer. The state in which the entire metal mesh is embedded in the active material layer includes a state in which the metal mesh is in contact with the current collector plate and a state in which the metal mesh is not in contact with the current collector plate. The state in contact with the current collector plate includes an integrated state.

  In the present invention, the current collector plate constituting the electrode is not made of punching metal or metal mesh, and the current collector plate itself has no opening. Therefore, in a secondary battery using the electrode of the present invention as a positive electrode and a negative electrode, a current can flow in the current collector in a state where the current density is large toward the active material non-coated portion when the secondary battery is discharged. The current collection efficiency is improved as compared with the case where the current collecting plate is made of a punching metal or a metal mesh. In addition, a metal mesh having a thickness smaller than that of the active material layer is provided in a state where at least a part is disposed in the active material layer, so that electricity generated in the active material is conducted to the current collector plate through the metal mesh. Is done. As a result, the output density of the power storage device is greater than when no metal mesh is present. Therefore, current collection efficiency can be improved, and both improvement in output density and energy density of the power storage device can be achieved. In addition, a plurality of polygonal openings are formed in the metal mesh, and at least the line width of each corner of one opening is smaller than twice the line width of the straight line of the opening. Therefore, current collection efficiency is further improved as compared with the case where expanded metal is used as a metal mesh.

  According to a second aspect of the present invention, in the first aspect of the present invention, the metal mesh has a belt-like portion where the opening is not formed at least at the end of the current collector plate on the side where the current collector terminal is joined. Have. When the metal mesh is thin, for example, 30 μm or less, wrinkles may occur when handling the metal mesh. However, in the present invention, since the metal mesh has a band-shaped portion where no opening is formed at the end of the current collector plate on the side where the current collector terminal is joined, the metal mesh is flat due to the presence of the band-shaped portion. Are easily held. In addition, since the band-shaped portion is formed on the side where the current collector terminal is joined, the electric power generated in the active material layer in a state where the electrode is used in the power storage device, compared to the case where the band-shaped portion is formed on the opposite side. Is efficiently collected on the electrode terminals.

  The invention according to claim 3 is the invention according to claim 1 or claim 2, wherein the current collector plate is not applied with an active material on a surface where the active material is applied. And the active material non-applied portion is provided along the entire area of the side on which the current collecting terminal is joined, and the metal mesh has an opening ratio of the opening portion of the active material non-active portion. The position closer to the application part is formed smaller than the position farther away. Here, the “active material non-application portion” means a portion where a current collecting terminal for electrically connecting the electrode and the electrode terminal of the power storage device is joined.

  When discharging in the power storage device, the current flows in a state where the current density increases as the electrode is closer to the portion where the electrode is bonded to the electrode terminal of the power storage device (for example, the portion bonded to the current collecting terminal). In this invention, the current collector plate is formed with an active material non-applied portion where the active material is not applied on the surface where the active material is applied, and the current collector terminal is joined to the active material non-applied portion. The metal mesh is formed so that the opening ratio of the opening portion is closer to the position closer to the active material non-applied portion than the distant position. Therefore, the electrode has a lower electrical resistance per unit area near the portion where the electrode is joined to the electrode terminal of the power storage device, so that the current collection efficiency is further improved. In addition, since the active material non-applied portion is provided along the entire area of the active material layer, the degree of freedom of the junction position of the current collecting terminal is increased.

  The invention according to claim 4 is the invention according to claim 3, wherein the opening of the metal mesh is located farther from the opening where the size of the opening is close to the active material non-application portion. The opening is formed smaller than the opening. In this invention, the size of the opening is smaller than the opening existing at a position closer to the active material non-applied portion than the opening existing at a far position. Therefore, the electrode has a lower electrical resistance per unit area near the portion where the electrode is joined to the electrode terminal of the power storage device, so that the current collection efficiency is further improved.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the current collecting plate is not coated with an active material on the surface on which the active material is coated. The active material non-applied portion is formed, the active material non-applied portion is provided as a tab portion, and the metal mesh is formed such that the opening ratio of the opening portion is closer to the tab portion than the far position. Has been. Therefore, in this invention, compared with the case where the metal mesh in which the aperture ratio of the opening part was formed constant is used, current collection efficiency improves.

  The invention according to claim 6 is the invention according to claim 5, wherein the metal mesh is present in a position where the size of the opening is closer to the tab portion and the opening is farther away. It is formed smaller than the opening. Therefore, in this invention, compared with the case where the metal mesh in which the magnitude | size of the opening part was formed constant is used, current collection efficiency improves.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the metal mesh is manufactured by etching a metal sheet. In this invention, since the metal mesh is formed by etching, the mesh shape and the size of the opening can be freely set as compared with the metal mesh formed of expanded metal or punching metal.

  The invention according to claim 8 is the method for manufacturing the power storage device according to any one of claims 1 to 7. And the electrode manufacturing process which manufactures the said electrode dries the active material apply | coated on the said current collector plate while apply | coating the said slurry-form or paste-form active material to the at least single side | surface of the said current collector plate, An active material layer forming step of forming an active material layer, wherein in the active material layer forming step, at least a part of a metal mesh having an opening formed by etching in the active material applied on the current collector plate The active material is dried in the disposed state to form the active material layer.

  In the active material layer forming step, when a part of the metal mesh is placed in the active material coated on the current collector plate, the active material is placed in a state where the metal mesh is placed on the current collector plate. Even if it apply | coats on a current collecting plate, you may arrange | position at least one part of a metal mesh in the active material apply | coated on the current collecting plate. The power storage device manufactured by the method of the present invention has the effect of the power storage device according to any one of claims 1 to 7 because the opening has a metal mesh formed by etching. .

  The invention according to claim 9 is a method of manufacturing an electrode for a power storage device having an active material layer in which an active material is applied on at least one side of a metal current collector plate, the surface of the current collector plate being After the active material layer is formed by applying the slurry or paste active material, a metal mesh is placed on the surface of the active material layer when the active material layer is soft, and the metal is A magnetic force was applied to the mesh from the side opposite to the side on which the metal mesh of the current collector plate was placed, and the metal mesh was drawn into the slurry or paste active material layer by the magnetic force. Thereafter, a step of drying the active material layer is provided. In the method for manufacturing an electrode for a power storage device according to the present invention, the embedding state of the metal mesh in the active material layer can be adjusted by adjusting the softness of the active material layer and the magnitude of the magnetic force applied to the metal mesh.

  A tenth aspect of the present invention is a secondary battery including the configuration of the power storage device according to any one of the first to seventh aspects. Therefore, the secondary battery of the present invention has the same effect as the power storage device according to any one of claims 1 to 7.

  According to the invention described in claims 1 to 8 and claim 10, there is provided a power storage device or a secondary battery capable of improving current collection efficiency and achieving both improvement in output density and improvement in energy density. be able to. According to invention of Claim 9, the electrode for electrical storage apparatuses suitable for the said electrical storage apparatus can be provided.

The 1st Embodiment is shown, (a) is a schematic plan view of the electrode for secondary batteries, (b) is the sectional view on the AA line of (a). (A) is a top view of a metal mesh, (b) is the elements on larger scale of (a), (c) is the elements on larger scale of (b). (A) is a schematic perspective view of the electrode body of the state which developed a part of positive electrode, a negative electrode, and a separator, (b) is a schematic cross section of a secondary battery. The schematic cross section of the electrode for secondary batteries of a 2nd embodiment. (A), (b), (c) is a schematic cross section for demonstrating the manufacturing method of the electrode for secondary batteries. The schematic plan view of the electrode for secondary batteries of 3rd Embodiment. The schematic cross section of a secondary battery. (A) is the elements on larger scale of the opening part of the metal mesh of another embodiment, (b) is the elements on larger scale of (a). The partial schematic diagram of the metal mesh of another embodiment. The schematic diagram which shows the relationship between the active material non-application part of another embodiment, and the opening part of a metal mesh. (A), (b) is a schematic cross section of the electrode for secondary batteries of another embodiment. The schematic perspective view of the electrode body of another embodiment. The elements on larger scale of the metal mesh of a prior art.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1A and 1B, the secondary battery electrode 10 as the power storage device electrode includes an active material layer 12 in which an active material is applied to at least one surface of a metal current collector plate 11. Have. In this embodiment, the active material is applied to both surfaces, and the active material layer 12 is formed on both surfaces of the current collector plate 11 as shown in FIG. The current collector plate 11 is formed of, for example, a strip-shaped copper foil. When the secondary battery is a lithium ion battery, an aluminum foil is used for the current collector plate 11 for the positive electrode, and the current collector plate 11 for the negative electrode is used. Copper foil is used.

  The active material varies depending on the type of secondary battery such as a nickel metal hydride battery and a lithium ion battery. Further, when the electrode body is formed even in the same type of secondary battery, it is different from what is applied to the positive electrode current collector plate 11 serving as the positive electrode and the negative electrode current collector plate 11 serving as the negative electrode.

  The current collector plate 11 is formed with an active material non-applied portion 13 where no active material is applied on the surface where the active material is applied, and the active material non-applied portion 13 is joined to a current collector terminal. In FIG. 1A, it is provided along the entire region of the upper end side. The active material layer 12 is provided with a metal mesh 14 that is thinner than the active material layer 12 in a state in which at least a part thereof is disposed in the active material layer 12. In this embodiment, the entire metal mesh 14 is embedded in the active material layer 12, and one side of the metal mesh 14 is provided integrally with the current collector plate 11.

  A plurality of polygonal openings 14a are formed in the metal mesh, and at least the line width Wc of each corner of one opening 14a is narrower than twice the line width W of the straight part of the opening 14a. In this embodiment, the metal mesh 14 is formed with regular polygons having the same size, and in this embodiment, regular hexagonal openings 14a. That is, the opening 14a is formed so that the shape of the inner peripheral surface of each corner is the same. However, as shown in FIG. 2A, an opening having a shape in which a part of the regular polygon is removed also exists in the peripheral portion of the metal mesh 14. As shown in FIG. 2C, the line width Wc of the corner portion of the opening 14a is the angle between the inner corner of the corner portion and the virtual intersection of the two straight line outlines corresponding to the corner. Distance.

  The metal mesh 14 has a belt-like portion 14b where the opening portion 14a is not formed at least at the end portion of the current collector plate 11 on the side where the current collecting terminals are joined. The metal mesh 14 is formed of the same material as the current collector plate 11, and when the secondary battery is a lithium ion battery, an aluminum foil is used for the metal mesh 14 used for the current collector plate 11 for the positive electrode. A copper foil is used for the metal mesh 14 used for the current collector plate 11.

  The width and length of the metal foil forming the metal mesh 14 are set corresponding to the size of the secondary battery in which the secondary battery electrode is used. For example, the metal mesh 14 has a thickness of 30 to 40 μm, and the size of the opening 14 a is such that the distance D between two opposite sides of the regular hexagon is about 800 μm, as shown in FIG. The width (line width W) is formed to be several tens of μm or less (for example, 20 μm). Moreover, the strip | belt-shaped part 14b is formed in width about several mm. In the case of a lithium ion battery, lithium easily precipitates when the width of each side of the opening 14a of the metal mesh 14 is increased. Therefore, the width and the size of the opening 14a are set in consideration thereof. 1A and 1B, the secondary battery electrode 10 includes a current collector plate 11, an active material layer 12, an active material non-applied portion 13, a metal mesh 14, an opening portion 14a, and a strip portion 14b. It is schematically represented by ignoring the size ratio. In particular, in order to make the opening portion 14a easy to understand, the opening portion 14a is shown larger than other portions.

  The metal mesh 14 is manufactured by etching. A known etching method is used for the etching, and it is manufactured by immersing in an etching solution in a state where a resist pattern is formed on a strip-shaped metal foil (metal sheet) as a material of the metal mesh 14. In the metal mesh 14 manufactured by etching, unlike the expanded metal, the line width Wc of each corner portion of one opening portion 14a is never twice the line width W of the other portion (straight line portion). Therefore, compared with the case where the metal mesh 14 is formed with expanded metal, the aperture ratio can be earned effectively. When the opening 14a is a regular polygon, if the angle of the corner is larger than a right angle, the unetched portion hardly remains and the aperture ratio can be more effectively earned.

  Further, when the metal mesh 14 is manufactured by etching, unlike the case where the metal mesh 14 is manufactured by an expanded metal, the mesh shape, that is, the shape of the opening 14a can be freely designed. Further, since the resist is produced by printing, once the plate is made, it can be used many times, and the cost of the plate becomes relatively low. In addition, when forming a resist pattern on a metal foil, a fine mesh (small mesh of the opening 14a) is produced by printing so as to have a desired resist pattern pitch using a negative mask of the same pattern. Can do.

Next, the manufacturing method of the electrode 10 for secondary batteries comprised as mentioned above is demonstrated.
In the method for manufacturing the secondary battery electrode 10, first, the current collector plate 11 is formed of a strip-shaped metal foil, and the metal mesh 14 formed of the strip-shaped metal foil is joined to the current collector plate 11. The joining is performed by welding, for example. The joining of the metal mesh 14 to the current collector plate 11 may be performed simultaneously on both surfaces of the current collector plate 11 or sequentially on each side. Next, an active material is applied to the current collector plate 11 to which the metal mesh 14 is bonded. The application process of the active material is the same as that of the prior art. For example, the active material layer is formed by supplying the paste active material directly from the active material supply unit to the region where the metal mesh 14 on the current collector plate 11 is bonded. 12 is formed. Alternatively, the active material layer 12 is formed by supplying the paste-like active material from the active material supply unit onto the transfer roller, and then transferring (supplying) the paste active material onto the current collecting plate 11 from the transfer roller. The application of the active material may be performed after the application to one side of the current collector plate 11 is finished, after the active material layer 12 is dried, or may be applied to the other side, or may be performed simultaneously on both sides.

  The secondary battery electrode 10 manufactured as described above becomes the secondary battery electrode 10p for the positive electrode or the secondary battery electrode 10n for the negative electrode depending on the applied active material. As shown in FIG. 3A, a positive electrode secondary battery electrode 10p having a positive electrode active material layer 12a coated with a positive electrode active material, and a negative electrode active material coated with a negative electrode active material. The negative electrode secondary battery electrode 10n having the material layer 12b is wound into a long cylindrical shape with the strip-shaped separator 15 interposed therebetween, whereby a wound electrode body 20 is formed. At this time, the secondary battery electrode 10p for the positive electrode and the secondary battery electrode 10n for the negative electrode have the active material non-applied part 13a for the positive electrode and the active material non-applied part 13b for the negative electrode wound around the electrode body 20. It is arranged and wound in a state located on the opposite side in the axial direction.

  As shown in FIG. 3B, the electrode body 20 includes a positive electrode current collecting terminal 21 and a negative electrode current collecting terminal 22 on the positive electrode active material non-applied part 13a and the negative electrode active material non-applied part 13b. Each is joined by welding and accommodated in a battery case (battery) 23, and a secondary battery 30 as a power storage device is configured together with the electrolytic solution 24. The positive current collector terminal 21 and the negative current collector terminal 22 are fixed to the positive terminal 31 and the negative terminal 32 of the secondary battery 30, respectively.

  The manufacturing method of the secondary battery 30 is different from the conventional manufacturing method in part of the electrode manufacturing process for manufacturing the electrode. In the electrode manufacturing process, a slurry-like or paste-like active material is applied to at least one surface of the current collector plate 11, and the active material applied on the current collector plate 11 is dried to form an active material layer 12. A layer forming step; In the active material layer forming step, the active material is dried in a state where at least a part of the metal mesh 14 having the openings 14a formed by etching is disposed in the active material applied on the current collector plate 11. Layer 12 is formed. In the active material layer forming step, the active material is applied and dried on the current collector plate 11 to which the metal mesh 14 is bonded, and an electrode in which at least a part of the metal mesh 14 is disposed in the active material is formed. .

Although the secondary battery 30 is used for various purposes, for example, it is also used in a state where it is mounted on a vehicle.
Next, the operation of the secondary battery 30 configured as described above will be described.

  When the secondary battery 30 is discharged (output), a current is taken out from the positive electrode current collecting terminal 21 of the positive electrode for secondary battery 10p. The current generated in the active material layer 12 flows in the thickness direction of the active material layer 12 toward the current collector plate 11, and then flows through the current collector plate 11 toward the portion where the positive electrode current collector terminal 21 is joined. The conductivity of the active material is smaller than the conductivity of the metal foil. Therefore, when the active material layer 12 is thickened by increasing the amount of the active material applied to increase the capacity of the secondary battery 30, when punching metal or a metal mesh is used as the current collector plate 11, the conductivity is reduced. The area of the large portion is reduced, current cannot flow in a state where the current density is large toward the active material non-applied portion 13 when the secondary battery 30 is discharged, and current collection efficiency deteriorates. As a result, the output density of the secondary battery 30, that is, the output per unit volume or the output per unit weight of the secondary battery 30 decreases.

  However, in this embodiment, the current collector plate 11 constituting the secondary battery electrode 10 is not composed of a punching metal or a metal mesh, and the current collector plate 11 itself has no opening 14a. Therefore, in the secondary battery 30 using the secondary battery electrode 10 as the positive electrode and the negative electrode, the current collector plate 11 has a large current density toward the active material non-coated portion 13 when the secondary battery 30 is discharged. A current can flow, and the current collection efficiency is improved as compared with the case where the current collecting plate 11 is made of a punching metal or a metal mesh. Further, since the metal mesh 14 having a thickness smaller than that of the active material layer 12 is provided in a state where at least a part is disposed in the active material layer 12, electricity generated in the active material is collected via the metal mesh 14. Conducted to the electric plate 11. As a result, the output density of the secondary battery 30 is greater than when the metal mesh 14 is not present.

According to this embodiment, the following effects can be obtained.
(1) The secondary battery electrode 10 has an active material layer 12 coated with an active material on at least one surface of a metal current collector plate 11, and a metal mesh 14 having a thickness smaller than that of the active material layer 12. , At least a portion of the active material layer 12 is provided. Therefore, the secondary battery 30 using the electrode body 20 using the positive electrode and the negative electrode of the configuration of the secondary battery electrode 10 has improved current collection efficiency compared to the configuration in which the metal mesh 14 is not present, and the secondary battery. 30 power density and energy density can be improved. The metal mesh 14 is formed with a plurality of polygonal openings 14a. At least the line width Wc of each corner of one opening 14a is twice the line width W of the straight part of the opening 14a. narrow. Therefore, the current collection efficiency is further improved as compared with the case where expanded metal is used as the metal mesh 14.

  (2) An active material layer 12 is formed on both sides of the current collector plate 11, and a metal mesh 14 is embedded in each active material layer 12. Therefore, compared with the case where the current collector plate 11 provided with the active material layer 12 and the metal mesh 14 on one side is used, the output density of the secondary battery 30 is further improved and the energy density is further improved.

  (3) The metal mesh 14 is embedded in the active material layer 12 in a state of being integrally joined to the current collector plate 11. Therefore, after the current flowing in the active material layer 12 reaches the metal mesh 14, it can flow from the metal mesh 14 to the current collector 11 without flowing through the active material layer 12. The current collection efficiency is further improved as compared with the configuration embedded in a state away from 11.

  (4) The metal mesh 14 is manufactured by etching. Therefore, the mesh shape and size can be freely formed. Further, unlike the metal mesh 14 formed of expanded metal, the width of the portion corresponding to the corner portion of the opening 14a is not twice that of the other portions. Therefore, compared with the case where the metal mesh 14 is formed with expanded metal, the aperture ratio can be earned effectively. In addition, the manufacturing cost can be reduced as compared with the case where the metal mesh 14 is manufactured using expanded metal.

(5) The metal mesh 14 is formed so that the shape of the inner peripheral surface of each corner portion of one opening 14a is the same. Therefore, for example, manufacturing by etching becomes easy.
(6) Since the opening 14a is formed in a regular hexagonal shape, the angle of each corner is larger than 90 degrees, an unetched portion is unlikely to occur, and the shape of the opening 14a is rectangular or equilateral triangular. Compared with the case where it is formed, the aperture ratio can be earned more effectively.

  (7) The metal mesh 14 has a belt-like portion 14b where the opening portion 14a is not formed at least on the side where the current collecting terminal of the current collecting plate 11 is joined, that is, on the end portion on the active material non-application portion 13 side. When the metal mesh 14 is thin, for example, 30 μm or less, wrinkles may occur when the metal mesh 14 is handled. However, since the band-like part 14b in which the opening part 14a is not formed is formed in the metal mesh 14, the presence of the band-like part 14b makes it easier for the metal mesh 14 to be held in a flat state and suppresses wrinkles. Can do. In addition, since the belt-like portion 14b is formed on the active material non-applied portion 13 side to which the current collector terminal is joined, the secondary battery electrode 10 is provided in a second state as compared with the case where the belt-like portion 14b is formed on the opposite side. In a state where the secondary battery 30 is used, electricity generated in the active material layer 12 is efficiently collected at the electrode terminals.

  (8) The active material non-applied portion 13 is provided along the entire region on the side where the current collecting terminals are joined. Therefore, unlike the case where the active material non-applied portion 13 is provided along a partial region of the active material layer 12 like a so-called tab portion, there is no need to remove a part of the active material non-applied portion 13. Become.

  (9) The secondary battery 30 is active on at least one surface of the secondary battery including the electrode body 20 using the positive electrode and the negative electrode having the configuration of the secondary battery electrode 10, that is, the metal current collector plate 11. This is a secondary battery including an electrode body 20 having an electrode having a structure having an active material layer 12 coated with a substance. Therefore, compared with the secondary battery using the electrode which uses a metal mesh or punching metal as a current collecting plate, the improvement of an output density and the improvement of an energy density can be made compatible. Moreover, the effect of the electrode 10 for secondary batteries mentioned above can be acquired.

  (10) The vehicle is equipped with the secondary battery 30. Therefore, the effect of the secondary battery can be obtained. Moreover, since the secondary battery 30 can achieve both an improvement in output density and an improvement in energy density, the output of the drive unit of the vehicle can be increased.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. In this embodiment, the structure and manufacturing method of the secondary battery electrode 10 are greatly different from those of the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The material of the metal mesh 14 used for the secondary battery electrode 10 of this embodiment needs to have a property of being attracted by magnetic force, and for example, nickel is used. In addition, when the active material is applied in the form of a slurry or paste on the current collector plate 11 and then a magnetic force is applied to the metal mesh 14 with the metal mesh 14 placed on the active material layer 12, The mesh 14 is configured to be able to maintain a soft state in which the mesh 14 can enter the active material layer 12.

  As shown in FIG. 4, an active material layer 12 is formed on both sides of a current collector plate 11 constituting the secondary battery electrode 10, and an active material non-applied portion 13 is formed on one end side in the width direction and on the left end side in FIG. Is provided along the entire area of the active material layer 12. The active material layer 12 is provided with a metal mesh 14 that is thinner than the active material layer 12 in an embedded state. The metal mesh 14 is provided in a state where the surface is not exposed from the active material layer 12 and the surface facing the current collector plate 11 is embedded in the active material layer 12 so as not to contact the current collector plate 11.

Next, a method for manufacturing the secondary battery electrode 10 configured as described above will be described with reference to FIGS. 5 (a), 5 (b), and 5 (c).
As shown in FIG. 5A, a metal mesh 14 is placed on the active material layer 12 in a state where the active material layer 12 is formed by applying a slurry-like or paste-like active material on one surface of the current collector plate 11. Put. In this state, the active material layer 12 cannot penetrate into the active material layer 12 due to its own weight, but if the metal mesh 14 is pressed from above or a magnetic force is applied to the metal mesh 14, The metal mesh 14 is soft enough to enter the active material layer 12.

  Next, when an electromagnet (not shown) is arranged below the current collector plate 11 and a magnetic force is applied to the metal mesh 14 for a predetermined time, the metal mesh 14 enters the active material layer 12 as shown in FIG. Then, the active material layer 12 moves to an intermediate portion in the thickness direction. After the active material layer 12 is dried in this state, a slurry-like or paste-like active material is applied to the opposite surface of the current collector plate 11 to form the active material layer 12 in FIG. As shown, a metal mesh 14 is placed on the active material layer 12. In this state, when a magnetic force is applied to the metal mesh 14 located on the soft active material layer 12 from the lower side of the current collector plate 11 as described above, the metal mesh 14 enters the active material layer 12. Then, the active material layer 12 moves to an intermediate portion in the thickness direction. When the active material layer 12 is dried in that state, the secondary battery electrode 10 in the state shown in FIG. 4 is manufactured.

According to the secondary battery electrode 10 of the second embodiment, the following effects are obtained in addition to the same effects as the first embodiment (1), (2), and (4) to (6). be able to.
(11) In the method of manufacturing the secondary battery electrode 10 according to this embodiment, the active material layer 12 is formed by applying a slurry-like or paste-like active material to the surface of the current collector plate 11 and then forming the active material layer 12. In the soft state, the metal mesh 14 is placed on the surface of the active material layer 12. In this state, a magnetic force is applied to the metal mesh 14 from the side opposite to the side on which the metal mesh 14 is placed on the current collector plate 11 to place the metal mesh 14 in the slurry-like or paste-like active material layer 12. After drawing in by magnetic force, the process of drying the active material layer 12 is provided. Therefore, the embedding state of the metal mesh 14 in the active material layer 12 can be adjusted by adjusting the softness of the active material layer 12 and the magnitude of the magnetic force applied to the metal mesh 14.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. In this embodiment, the electrode 10 for the secondary battery is not configured to be suitable for the wound electrode body 20, but is configured to be suitable for a laminated electrode body, and the opening 14 a of the metal mesh 14. This is largely different from the first embodiment in that the opening 14a existing near the active material non-applied portion 13 is smaller than the opening 14a existing farther away. Further, the metal mesh 14 is formed such that the opening ratio of the opening 14a is closer to the position closer to the active material non-applied portion 13 than the position farther away. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the secondary battery electrode 10 has a tab portion as an active material non-applied portion near one end in the longitudinal direction (the left-right direction in FIG. 6) of the rectangular current collector plate 11 made of metal. 16 is protrudingly formed. In the metal mesh 14 embedded in the active material layer 12, the shape of the opening 14 a is not a regular hexagonal shape but a rectangular shape (in this embodiment, a regular square shape). In addition, the metal mesh 14 is not formed with all the openings 14a having the same size, but as shown in FIG. 14a is formed smaller than the opening 14a existing at a far position. The line width of the straight portion of the metal mesh 14 is formed to be constant, and the opening ratio of the opening portion 14a is formed smaller at a position closer to the active material non-applied portion 13 than at a far position.

  The secondary battery electrode 10 configured as described above becomes the secondary battery electrode 10p for the positive electrode or the secondary battery electrode 10n for the negative electrode depending on the applied active material. A plurality of positive electrode electrodes 10p for positive electrodes and a plurality of negative electrode electrodes 10n for negative electrodes are alternately stacked with a separator 15 in between to form a stacked electrode body 20. As shown in FIG. 7, the positive electrode secondary battery electrode 10 p and the negative electrode secondary battery electrode 10 n have the positive electrode tab portion 17 p and the negative electrode tab portion 17 n on the same side of the electrode body 20. Are disposed so as to protrude from each other.

  Then, as shown in FIG. 7, the positive electrode current collector terminal 21 and the negative electrode current collector terminal 22 are joined to the electrode body 20 by welding to the positive electrode tab portion 17p and the negative electrode tab portion 17n, respectively. The battery case (battery) 23 is housed, and the secondary battery 30 is configured together with the electrolyte solution 24. The positive current collector terminal 21 and the negative current collector terminal 22 are fixed to the positive terminal 31 and the negative terminal 32 of the secondary battery 30, respectively.

  When discharging is performed by the secondary battery 30, the current flows in a state where the current density increases as the electrode is closer to the part where the electrode is joined to the electrode terminal of the secondary battery 30 (for example, the part joined to the current collecting terminal). In this embodiment, the size of the opening portion 14a of the metal mesh 14 is smaller than the opening portion 14a present in a position farther away from the opening portion 14a present in the position closer to the active material non-applied portion (tab portion 16). Since the opening ratio of the opening 14a is smaller at the position closer to the active material non-applied portion 13 than the position far from it, it can cope with an increase in the amount of current flowing through the metal mesh 14. Electric efficiency is further improved. Moreover, since the active material non-application part is provided as the tab part 16, the active material non-application part is provided along the whole region of the active material layer 12, and the size of the opening part 14a of the metal mesh 14 is large. The current collection efficiency is further improved as compared to the case where the opening 14a existing near the active material non-applied portion is formed smaller than the opening 14a existing farther away.

The embodiment is not limited to the above, and may be embodied as follows, for example.
○ When the metal mesh 14 is manufactured by etching, the shape of the opening 14a can be freely changed, unlike the case of forming with expanded metal, and is not limited to a regular hexagon or a rectangle, but a triangle, a pentagon, or a heptagon It may be a polygon. However, when the angle of the corner of the opening 14a becomes a right angle, as shown in FIGS. 8A and 8B, the unetched portion 14c tends to remain in the corner, and the angle of the corner is smaller than 90 degrees. The unetched portion 14c is likely to remain. Therefore, when the shape of the opening 14a is a polygon, the angle of the corner is preferably larger than 90 degrees. A metal mesh 14 having a regular square opening 14a shown in FIG. 8A is formed by forming a distance D between two sides of the opening 14a of about 800 μm and a width of each side of about 20 μm. The unetched portion 14c remained. In this case, as shown in FIG. 8B, the line width Wc of the corner portion of the opening 14a is the distance between the opposing outlines of the unetched portion of the corner portion.

The shape of the opening 14a is not limited to a polygon, and may be another shape formed only by a curve or a shape formed by a curve and a straight line.
The metal mesh 14 is not limited to one in which the shape of the inner peripheral surface of each corner portion of one opening portion 14a is the same.

  ○ The openings 14a may have different shapes. For example, by changing a part of a pattern in which a plurality of regular hexagons are continuous, as shown in FIG. 9, regular hexagonal openings 14a, octagonal openings 14a, and rectangular openings 14a are mixed. You may do it.

  ○ When the belt-like portion 14b is provided on the metal mesh 14, the belt-like portion 14b is not only applied on the side where the current collecting terminal of the current collector plate 11 is connected, that is, on the active material non-applying portion 13 side, but also on the active material non-applied In the case of the secondary battery electrode 10 for the laminated electrode body 20, the strip 14b is provided in a frame shape along the periphery of the secondary battery electrode 10. May be. Moreover, you may provide the strip | belt-shaped part 14b only in one place on the opposite side to the active material non-application part 13. FIG.

  A metal mesh 14 may be used that does not have the band-like part 14b at any end part. However, when the metal mesh 14 is embedded in the active material layer 12 by the method as in the second embodiment, the active material layer in which the metal mesh 14 is softer in a state in which the metal mesh 14 has better flatness is provided. This is preferable because it can penetrate into the layer 12 and is easily embedded in a desired position.

  Even when the active material non-applied portion 13 is provided on the current collector plate 11 along the entire area of the active material layer, as shown in FIG. 10, an opening portion is formed as the metal mesh 14 embedded in the active material layer 12. An opening 14a having a size of 14a closer to the active material non-applied portion 13 than the opening 14a existing at a farther position may be used. Also in this case, the current collection efficiency is further improved as compared with the case where the metal mesh 14 having a constant size of the opening 14a, that is, the aperture ratio does not change.

  The metal mesh 14 constituting the secondary battery electrode 10 is not limited to a configuration in which at least a part is disposed in the active material layer 12, and is entirely embedded (arranged) in the active material layer 12. As shown to Fig.11 (a), the structure embedded at the active material layer 12 in the state which the surface exposes may be sufficient. Also in this case, the current collection efficiency is improved as compared with the case where the metal mesh 14 is not provided. Although the metal mesh 14 shown in FIG. 11A does not have the belt-like portion 14b, the metal mesh 14 having the belt-like portion 14b may be used.

  O As shown in FIG.11 (b), you may apply to the thing in which the active material layer 12 was formed only in the single side | surface of the current collecting plate 11. FIG. Even when the active material layer 12 is formed only on one surface of the current collector plate 11, the metal mesh 14 is embedded (arranged) in a state where the metal mesh 14 is in contact with or integrated with the current collector plate 11 or the metal mesh 14. May be a position away from the current collector plate 11 and the surface of the active material layer 12. The metal mesh 14 shown in FIG. 11B also does not have the belt-like portion 14b, but the metal mesh 14 having the belt-like portion 14b may be used.

  ○ As shown in FIG. 12, the wound electrode body 20 is applied to a structure in which a positive electrode tab portion 17p and a negative electrode tab portion 17n are projected on the same side of the electrode body 20. May be. In this case, a plurality of positive electrode tabs 17p are integrally formed on the same side in the winding axis direction and wound on the positive electrode for secondary battery 10p. The tab portions 17p are formed at predetermined intervals overlapping each other in the radial direction with respect to the winding axis. Similarly, the negative electrode for a secondary battery 10n has a plurality of negative electrode tabs 17n formed at predetermined intervals.

  The method for manufacturing the secondary battery electrode 10 in which the metal mesh 14 is embedded (arranged) in the active material layer 12 is not limited to the method of the first embodiment or the second embodiment. For example, depending on the type of binder (for example, binder) of the active material, the metal mesh 14 joins a method disclosed in Patent Document 1, that is, a sheet formed by kneading the active material together with the binder and preforming. It may be manufactured by pressure bonding to the current collector plate 11. Further, when the metal mesh 14 is embedded in the active material layer 12 in a soft state, instead of applying a magnetic force to the metal mesh 14, the metal mesh 14 is mechanically pressed from above the metal mesh 14 to a desired position. The active material layer 12 may be penetrated.

  ○ When manufacturing the secondary battery electrode 10 by applying a magnetic force to the metal mesh 14 so that the metal mesh 14 enters a predetermined position in the slurry-like or paste-like active material layer 12, the metal mesh 14 is etched. For example, a metal mesh 14 formed of expanded metal may be used.

  The power storage device is not limited to the secondary battery 30 and may be a capacitor such as an electric double layer capacitor or a lithium ion capacitor.

  W, Wc: Line width, 10, 10n, 10p ... Secondary battery electrode, 11 ... Current collector plate, 12 ... Active material layer, 13 ... Active material non-application part, 14 ... Metal mesh, 14a ... Opening part, 14b ... strip-shaped part, 16, 17n, 17p ... tab part, 20 ... electrode body, 30 ... secondary battery as a power storage device.

Claims (10)

A power storage device comprising an electrode body having an electrode having a structure having an active material layer coated with an active material on at least one side of a metal current collector plate,
A metal mesh having a thickness smaller than that of the active material layer is provided in a state where at least a part is disposed in the active material layer, and the metal mesh has a plurality of polygonal openings, and at least, The power storage device, wherein a line width of each corner portion of one opening is narrower than twice a line width of a straight portion of the opening.   2. The power storage device according to claim 1, wherein the metal mesh has a belt-like portion where the opening is not formed at least at an end portion of the current collector plate on a side where a current collecting terminal is joined.   The current collector plate is formed with an active material non-applied portion where the active material is not applied on the surface where the active material is applied, and the active material non-applied portion is on the side where the current collector terminal is joined The metal mesh is formed so that the opening ratio of the opening portion is smaller at a position closer to the active material non-applied portion than at a position farther away. 2. The power storage device according to 2.   4. The metal mesh according to claim 3, wherein the size of the opening is formed to be smaller than the opening that exists at a position farther away from the opening that is present at a position closer to the active material non-applied portion. Power storage device.   The current collector plate has an active material non-applied portion where no active material is applied on a surface where the active material is applied, and the active material non-applied portion is provided as a tab portion, and the metal mesh 5. The power storage device according to claim 1, wherein the aperture ratio of the opening is formed smaller at a position closer to the tab portion than at a far position.   The power storage device according to claim 5, wherein the metal mesh is formed so that the size of the opening is smaller than the opening that exists at a position farther away from the opening that is present at a position closer to the tab portion.   The power storage device according to any one of claims 1 to 6, wherein the metal mesh is manufactured by etching a metal sheet. A method of manufacturing a power storage device including an electrode body having an electrode having a structure having an active material layer coated with an active material on at least one surface of a metal current collector plate,
In the electrode manufacturing process for manufacturing the electrode, the active material applied in a slurry or paste form is applied to at least one surface of the current collector plate, and the active material applied on the current collector plate is dried. An active material layer forming step of forming a layer, wherein in the active material layer forming step, at least a part of a metal mesh having openings formed by etching is disposed in the active material applied on the current collector plate. The method for manufacturing a power storage device is characterized in that the active material is dried to form the active material layer.   A method of manufacturing an electrode for a power storage device having an active material layer coated with an active material on at least one surface of a metal current collector plate, wherein the active material is in a slurry or paste form on the surface of the current collector plate After forming the active material layer by applying a metal mesh on the surface of the active material layer when the active material layer is soft, the current collector plate with respect to the metal mesh in that state A magnetic force is applied from the side opposite to the side on which the metal mesh is placed, and the metal mesh is drawn into the slurry-like or paste-like active material layer by the magnetic force, and then the active material layer is dried. A method for manufacturing an electrode for a power storage device, comprising a step.   The secondary battery provided with the structure of the electrical storage apparatus of any one of Claims 1-7.