JP2013101877A - Electrode for secondary battery, method for manufacturing electrode for secondary battery, secondary battery and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode for a secondary battery, capable of reducing time required for impregnating an electrolyte into an active material layer in manufacturing a secondary battery.SOLUTION: An electrode 10 for a secondary battery comprises an electrode having an active material layer 12 including an active material coated on at least one side of a metal collector plate 11. The active material layer 12 is formed on both sides of the collector plate 11 in two layers, respectively. A surface layer 15 as the active material layer on the most surface side is not coated on the whole surface of an inner layer 13, but a plurality of grooves 16, at least each one end of which reaches an outer peripheral end of the surface layer 15, are formed in the surface layer. The surface layer 15 is intermittently coated, and each of the grooves 16 extends in a direction orthogonal to the longitudinal direction of the collector plate 11 and both ends thereof reach the outer peripheral end of the surface layer 15.

Description

  The present invention relates to a secondary battery electrode, a method for manufacturing a secondary battery electrode, a secondary battery, and a vehicle.

  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 metal current collector plate 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.

  The basic configuration of the secondary battery is a stacked state in which a strip-shaped separator is sandwiched between a positive electrode current collector plate and a negative electrode current collector plate coated (supported) with an active material on a metal current collector plate A power generation element (electrode assembly) is configured, and the power generation element is accommodated in the battery case together with the electrolyte. The secondary battery manufacturing process includes a step of impregnating an electrolyte into an active material applied to a current collector plate constituting a power generation element housed in a battery case. Takes a long time and productivity decreases.

  As a method for improving the impregnation property of the electrolytic solution, as shown in FIG. 5, between the pair of grooving rollers 50 and 51 having the grooving protrusions 50a and 51a, for collecting current made of a long strip of copper foil. A method has been proposed in which a groove 55 is formed in the positive electrode active material layers 53 on both sides by passing a positive electrode plate hoop material 54 in which the positive electrode active material layers 53 are formed on both sides of the core material 52 (see Patent Document 1). .

JP 2010-186737 A

  However, since the groove part 55 formed by the method of Patent Document 1 is formed by compressing the positive electrode active material layer 53, the positive electrode active material layer 53 of the groove part 55 has a high density and inhibits impregnation of the electrolytic solution.

  The present invention has been made in view of the above-described problems, and its purpose is to reduce the time required for impregnating the active material layer with the electrolytic solution when manufacturing a secondary battery. It is providing the battery electrode, the manufacturing method of the electrode for secondary batteries, a secondary battery, and the vehicle carrying the secondary battery.

  To achieve the above object, the invention according to claim 1 is an electrode for a secondary battery comprising an electrode having an active material layer coated with an active material on at least one surface of a metal current collector plate, The active material layer is applied in multiple layers on at least one surface of the current collector plate, and the active material layer on the most surface side has a plurality of grooves that reach at least one end to the outer peripheral edge of the active material layer on the most surface side. Has been.

  When the active material layer applied to the current collector plate is impregnated with the electrolytic solution, the time required for the impregnation becomes longer as the thickness of the active material layer is the same. When the thickness of the active material layer is reduced by compressing the active material layer, the density increases as the thickness is reduced, so that the effect of shortening the time required for impregnation is low. However, in this invention, the active material layer applied to at least one surface of the current collector plate is composed of a plurality of layers, and the active material layer on the most surface side is a groove that reaches at least one end to the outer peripheral edge of the active material layer on the most surface side. Are formed, and the groove is formed without compressing the active material layer. Therefore, the portion where the groove is formed is more quickly impregnated with the electrolyte than the other portion. Further, since the electrolyte solution is impregnated not only from the surface but also from the groove portion in the portion where the groove is not formed, the impregnation of the electrolyte solution is accelerated. Accordingly, it is possible to reduce the time required for impregnating the active material layer with the electrolytic solution when manufacturing the secondary battery.

  According to a second aspect of the present invention, in the first aspect of the present invention, the active material layer is applied to both surfaces of the current collector plate. If the amount of active material applied to one electrode plate is the same, the thickness of the active material layer formed on both sides of the electrode plate is halved compared to the case where it is formed on one side, When manufacturing the secondary battery, it is possible to shorten the time required for impregnating the active material layer with the electrolytic solution.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the active material layer on the most surface side is applied intermittently. Here, “intermittently applied” means that there is not one active material layer that constitutes the active material layer on the most surface side, and a plurality of parts are independent at intervals in the longitudinal direction of the current collector plate. Means it exists. In this invention, since the active material layer on the most surface side is applied intermittently, the active material layer on the most surface side has a groove where at least one end reaches the outer peripheral end of the active material layer on the most surface side. It becomes a state. In general, in a secondary battery, an electrode is accommodated in a battery case in a state of being stacked in a plurality of layers with a separator interposed therebetween, and an electrolytic solution impregnates an active material layer of the electrode from between the electrode and the separator. At this time, if there is a groove having at least one end reaching the outermost edge of the active material layer on the most surface side, the electrolytic solution is likely to enter the groove and impregnation into the active material layer becomes faster.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the current collector plate has a shape extending in one direction, and the groove is a length of the current collector plate. It extends in a direction orthogonal to the direction, and both ends reach the outer peripheral end of the outermost active material layer. In the present invention, the application of the active material using a roller is facilitated as compared with the groove formed with the groove inclined with respect to the longitudinal direction of the current collector plate.

  Invention of Claim 5 is a secondary battery using the electrode for secondary batteries as described in any one of Claims 1-4. The effect of the secondary battery electrode according to any one of claims 1 to 4 is obtained in the secondary battery of the present invention.

The invention described in claim 6 is a vehicle on which the secondary battery according to claim 5 is mounted. Therefore, the vehicle of the present invention can achieve the effect of the secondary battery according to claim 5.
The invention according to claim 7 is a method for producing an electrode for a secondary battery comprising an electrode having an active material layer coated with an active material on at least one surface of a metal current collector plate, wherein the application of the active material In the process, the current collecting plate is applied in a plurality of times so that there are a plurality of active material layers, and the active material layer on the most surface side is applied intermittently. Accordingly, the active material layer on the most surface side has a groove reaching the outer peripheral edge of the active material layer on the most surface side, and the time required for impregnating the electrolyte into the active material layer when the secondary battery is manufactured. An electrode for a secondary battery that can be shortened can be easily manufactured.

  The invention according to claim 8 is the invention according to claim 7, wherein the application of the active material layer on the most surface side is performed using a transfer roller. When the active material is applied to the current collector plate, the active material paste is applied directly on the current collector plate or on the active material layer applied to the current collector plate. It is difficult to apply intermittently. However, in the present invention, since the active material of the active material layer on the most surface side is applied using a transfer roller, the active material is easily and intermittently applied at a desired interval even when the current collector plate moves. be able to.

  According to the first to fourth aspects of the present invention, there is provided a secondary battery electrode capable of shortening the time required for impregnating the active material layer with the electrolyte when manufacturing the secondary battery. be able to. According to invention of Claim 5, the secondary battery from which the effect of the said electrode for secondary batteries is acquired can be provided. According to invention of Claim 6, the vehicle from which the effect of the said secondary battery is acquired can be provided. According to invention of Claim 7 and Claim 8, when manufacturing a secondary battery, the manufacturing method of the electrode for secondary batteries which can aim at shortening of the time which impregnation of the electrolyte solution to an active material layer is aimed at Can be provided.

(A) is a schematic plan view of an electrode, (b) is a schematic side view. (A) is a schematic diagram which shows the coating method of the active material using a transfer roller, (b) is a schematic diagram which shows the coating method of a surface layer. The graph which shows the relationship between electrolyte solution impregnation time and electrode resistance. (A), (b) is a schematic top view of the electrode of another embodiment, (c) is a schematic diagram which shows the shape of the groove | channel of another embodiment. The perspective view of a prior art.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIGS. 1A and 1B, the secondary battery electrode 10 is composed of an electrode having an active material layer 12 in which an active material is applied to at least one surface of a metal current collector plate 11. In this embodiment, the current collector plate 11 is formed of, for example, a strip-shaped copper foil, and the active material layer 12 is applied to both sides of the current collector plate 11 in a plurality of layers. In this embodiment, the active material layer 12 is formed in two layers, and the inner layer 13 is applied to the entire surface of the current collector plate 11 excluding the constant width active material non-applied portion 14 existing on both sides in the width direction. . The surface layer 15 as the active material layer on the most surface side is not applied to the entire surface of the inner layer 13, but a plurality of grooves 16 reaching at least one end to the outer peripheral end of the surface layer 15 are formed. The active material constituting the inner layer 13 and the active material constituting the surface layer 15 are the same.

  In this embodiment, the surface layer 15 is applied intermittently. The current collector plate 11 has a shape extending long in one direction, the groove 16 extends in a direction perpendicular to the longitudinal direction of the current collector plate 11, and both ends reach the outer peripheral end of the surface layer 15. That is, on the inner layer 13, a plurality of surface layers 15 exist independently at intervals in the longitudinal direction of the current collector plate 11. The interval L between the grooves 16 is, for example, greater than the width of the inner layer 13.

  The active material varies depending on the type of secondary battery such as a nickel metal hydride battery and a lithium ion battery. Further, even if the same type of secondary battery is applied to the positive electrode, it is different from that applied to the negative electrode.

Next, the manufacturing method of the electrode 10 for secondary batteries comprised as mentioned above is demonstrated.
As a method for manufacturing the secondary battery electrode 10, the application process of the active material is different from the conventional process, and the other processes are basically the same, and thus the description thereof is omitted. The active material application process includes an inner layer application process for forming the inner layer 13 and a surface layer application process for forming the surface layer 15, and the inner layer application process is performed in the same manner as before. And the surface layer 15 is apply | coated by the surface layer application | coating process on the inner layer 13 of the current collecting plate 11 with which the inner layer 13 formed by the inner layer application | coating process was apply | coated.

  In the surface layer application step, the surface layer 15 is intermittently applied using a transfer roller. As shown in FIG. 2, the coating apparatus using the transfer roller is provided with a transfer roller 21 and a nip roller 22 facing each other, and the transfer roller 21 is moved by a driving device (not shown) so as to be able to approach and separate from the nip roller 22. It has come to be. Below the transfer roller 21 and the nip roller 22, a guide roller 23 for guiding the belt-shaped current collector plate 11 is provided. The current collecting plate 11 coated with the inner layer 13 is supplied from a current collecting plate supply roller (not shown), and after passing between the transfer roller 21 and the nip roller 22 via the guide roller 23, the guide roller (not shown). And is wound around a winding roller (not shown). In addition to the guide roller, a tension adjusting mechanism (not shown) is provided on the moving path of the current collector plate 11. In the vicinity of the transfer roller 21, an active material supply unit 24 that supplies a paste-like active material onto the transfer roller 21 is provided so as to be movable integrally with the transfer roller 21.

  The active material supplied to the transfer roller 21 from the active material supply unit 24 is transferred onto the current collector plate 11 nipped by the transfer roller 21 and the nip roller 22 at the transfer position where the transfer roller 21 approaches the nip roller 22. In addition, when the transfer roller 21 is located at a position where the nip of the current collector plate 11 is released away from the nip roller 22, the active material on the transfer roller 21 is not transferred onto the current collector plate 11. The active material supply unit 24 can be switched between a state where the active material can be supplied onto the transfer roller 21 and a state where supply is stopped by a mechanism (not shown). Then, by controlling the approach and separation of the transfer roller 21 to and from the nip roller 22 and the supply and stop of the active material from the active material supply unit 24 to the transfer roller 21, as shown in FIG. An active material layer 12 having an arbitrary length can be applied on the electric plate 11.

  Then, with the active material being supplied from the active material supply unit 24 at regular intervals, the transfer roller 21 repeatedly approaches and separates from the nip roller 22 at a predetermined timing, as shown in FIG. Further, the active material is intermittently applied as the surface layer 15 on the current collector plate 11 on which the inner layer 13 (not shown) is formed in the inner layer application step. The current collector plate 11 on which the active material is applied on one side and the surface layer 15 is formed on one side is wound around a winding roller. Then, the current collector plate 11 having the surface layer 15 formed on one side is formed with the current collector plate 11 having the surface layer 15 formed on both sides by applying the active material to the opposite surface in the same manner as described above. . In FIG. 2B, the interval between the adjacent surface layers 15 is shown wider than the length of the surface layer 15 in order to make it easy to understand that the surface layers 15 are applied at equal intervals.

Next, the operation of the secondary battery electrode 10 configured as described above will be described.
The basic configuration of the secondary battery is a belt-like shape between the positive electrode secondary battery electrode 10 and the negative electrode secondary battery electrode 10 in which an active material is applied (supported) to a metal current collector plate 11. The power generation element (electrode assembly) is configured in a stacked state with the separator interposed therebetween, and the power generation element is housed in the battery case together with the electrolytic solution. The manufacturing process of the secondary battery includes a step of impregnating the active material layer 12 applied to the current collector plate 11 constituting the power generation element housed in the battery case with an electrolyte solution. If the thickness is too thick, it takes time to impregnate and the productivity becomes poor.

  When the active material layer 12 applied to the current collector plate 11 is impregnated with the electrolytic solution, the time required for the impregnation becomes longer as the thickness of the active material layer 12 is the same. When the thickness of the active material layer 12 is reduced by compressing the active material layer 12, the density is increased as much as the thickness is reduced, so that the effect of shortening the time required for impregnation is low. However, in the secondary battery electrode 10 of this embodiment, the active material layer 12 applied to both surfaces of the current collector plate 11 is composed of a plurality of layers, and at least one end of the surface layer 15 reaches the outer peripheral end of the surface layer 15. Since a plurality of grooves 16 are formed, the portion where the grooves 16 are formed is more quickly impregnated with the electrolyte than the other portions. Further, since the electrolytic solution is impregnated not only from the surface but also from the portion of the groove 16 in the portion where the groove 16 is not formed, the impregnation of the electrolytic solution is accelerated.

  In order to confirm the effect of the groove 16 on the impregnation property of the electrolytic solution to the active material layer 12 constituting the secondary battery electrode 10, the surface layer 15 was intermittently formed on the inner layer 13 of the current collector plate 11. Secondary battery electrode (Example) and secondary battery electrode in which one active material layer 12 having the total thickness of the inner layer 13 and the surface layer 15 is formed on the current collector plate 11 as a comparative example. Formed. For the secondary battery electrodes of the example and the comparative example, the relationship between the electrolyte impregnation time and the electrode resistance was examined. The results are shown in FIG. In FIG. 3, the vertical axis represents electrode resistance, and the horizontal axis represents immersion time.

  The electrode resistance is in the order of kΩ (kiloohm) at the time of starting the impregnation of the electrolyte for the secondary battery electrode. Stabilization, that is, almost constant value. Confirmation that the electrolytic solution is impregnated in the entire active material layer 12 is performed by stabilizing the electrode resistance on the order of mΩ. As shown in FIG. 3, the electrode for the secondary battery of the example had a higher rate of decrease in electrode resistance than the electrode for the secondary battery of the comparative example, and the time required for stabilization was shortened. Compared with the comparative example, in the example, it was stabilized in about ¼ time.

Although the secondary battery using the secondary battery electrode 10 having the above-described configuration is used for various purposes, for example, it is also used in a state where it is mounted on a vehicle.
According to this embodiment, the following effects can be obtained.

  (1) The secondary battery electrode 10 includes an electrode having an active material layer 12 in which an active material is applied to at least one surface of a metal current collector plate 11, and the active material layer 12 is at least one surface of the current collector plate 11. A plurality of grooves 16 reaching at least one end to the outer peripheral end of the surface layer 15 are formed in the active material layer (surface layer 15) on the most surface side. Therefore, the impregnation with the electrolytic solution is accelerated compared to the case where the groove 16 is formed by compressing the active material layer 12. Therefore, it is possible to reduce the time required for impregnating the active material layer 12 with the electrolyte when manufacturing the secondary battery.

  (2) The active material layer 12 is applied to both surfaces of the current collector plate 11. When the amount of active material applied to one current collector plate 11 is the same, the thickness of the active material layer 12 formed on both sides of the current collector plate 11 is larger than that formed on one side. Thus, the time required for impregnating the active material layer 12 with the electrolytic solution can be reduced when the secondary battery is manufactured.

  (3) Since the surface layer 15 is intermittently applied, the surface layer 15 is in a state in which there are grooves 16 whose both ends reach the outer peripheral end of the surface layer 15. Therefore, compared with the case where a groove whose one end reaches the outer peripheral end of the surface layer 15 is formed, the electrolytic solution easily enters the groove 16 and the active material layer 12 is impregnated faster.

  (4) The current collector plate 11 has a shape extending long in one direction, the groove 16 extends in a direction perpendicular to the longitudinal direction of the current collector plate 11, and both ends reach the outer peripheral end of the surface layer 15. Therefore, the application of the active material using a roller becomes easier as compared with the groove 16 formed in a state inclined with respect to the longitudinal direction of the current collector plate 11.

  (5) The manufacturing method of the electrode for secondary batteries is an application process of the active material with respect to the electrode for secondary batteries which consists of an electrode which has the active material layer 12 with which the active material was apply | coated to the at least single side | surface of the metal current collecting plates 11. In FIG. 2, the active material layer 12 is applied in a plurality of times so that the active material layer 12 becomes a plurality of layers, and the active material layer (surface layer 15) on the most surface side is applied intermittently. Therefore, as the surface layer 15, there are grooves 16 whose both ends reach the outer peripheral end of the surface layer 15, and it is possible to easily manufacture the secondary battery electrode 10 capable of shortening the time required for impregnation with the electrolytic solution. it can.

  (6) The surface layer 15 is applied using the transfer roller 21. When the active material is applied to the current collector plate 11, the current collector plate 11 moves in a method in which the active material paste is directly applied onto the current collector plate 11 or the active material layer 12 applied to the current collector plate 11. It is difficult to apply intermittently at desired intervals in the state. However, since the surface layer 15 is applied using the transfer roller 21, the active material layer 12 can be easily and intermittently applied at a desired interval even when the current collecting plate 11 is moved.

(7) The secondary battery using the secondary battery electrode 10 configured as described above can obtain the effects of the secondary battery electrode 10.
(8) When the secondary battery is mounted on a vehicle and used, the vehicle can obtain the effects of the secondary battery.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The active material layer 12 may be formed only on one side, not on both sides of the current collector plate 11. That is, the active material layer 12 only needs to be formed on at least one surface of the current collector plate 11.

  The grooves 16 are not limited to those extending in the direction orthogonal to the longitudinal direction of the current collector plate 11, and for example, as shown in FIG. 4A, the grooves 16 extending in the direction inclined with respect to the longitudinal direction of the current collector plate 11 are provided. A surface layer 15 may be applied to form.

  The surface layer 15 may be applied on the inner layer 13 with a width narrower than that of the inner layer 13, as shown in FIG. 4B, instead of being applied with the same width as the inner layer 13. . In this case, the impregnation with the electrolytic solution is performed earlier.

The interval L between adjacent grooves 16, that is, the length of the surface layer 15 is not constant, and there may be portions with different intervals L.
The surface layer 15 is not limited to a state in which there are a plurality of grooves 16 whose both ends reach the outer peripheral end of the surface layer 15, and a plurality of grooves 16 whose at least one end reaches the outer peripheral end of the surface layer 15 are formed. For example, as shown in FIG. 4 (c), adjacent surface layers 15 are formed in a state where one end in the width direction continues through the continuous portion 15 a, and the groove 16 has both ends extending to the outer peripheral end portion of the surface layer 15. The structure which one end reaches to the outer periphery edge part of the surface layer 15 may be sufficient instead of the structure which reaches | attains.

The secondary battery electrode 10 is not limited to the configuration in which the active material non-applied portions 14 are provided on both sides in the width direction of the current collector plate 11, but may be configured in one side in the width direction.
In the case where the surface layer 15 is intermittently formed by intermittently applying the active material paste on the inner layer 13 applied on the current collector plate 11, instead of applying using the transfer roller 21, the active material You may make it supply the paste of an active material directly on the inner layer 13 from the supply part 24. FIG. Alternatively, the active material paste may be directly supplied onto the inner layer 13 by a nozzle jet ink jet method or a coating method.

  The active material layer 12 formed on the current collector plate 11 may be a plurality of layers, and two or more inner layers 13 may exist inside the surface layer 15. Further, when two or more inner layers 13 are present, the widths of all the inner layers 13 are not the same and the width of the inner layer 13 closer to the surface layer 15 may be narrow.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery electrode, 11 ... Current collector plate, 12 ... Active material layer, 15 ... Surface layer as active material layer on the most surface side, 16 ... Groove, 21 ... Transfer roller.

Claims (8)

  An electrode for a secondary battery comprising an electrode having an active material layer coated with an active material on at least one side of a metal current collector plate, wherein the active material layer is applied to a plurality of layers on at least one side of the current collector plate An electrode for a secondary battery, wherein the active material layer on the outermost surface is formed with a plurality of grooves that reach at least one end to the outer peripheral end of the active material layer on the outermost surface.   The secondary battery electrode according to claim 1, wherein the active material layer is applied to both surfaces of the current collector plate.   The electrode for a secondary battery according to claim 1, wherein the active material layer on the most surface side is intermittently applied. The current collector plate has a shape extending long in one direction,
4. The secondary battery according to claim 1, wherein the groove extends in a direction orthogonal to the longitudinal direction of the current collector plate, and both ends reach the outer peripheral end of the outermost active material layer. Electrode.   The secondary battery using the electrode for secondary batteries as described in any one of Claims 1-4.   A vehicle equipped with the secondary battery according to claim 5.   A method for producing an electrode for a secondary battery comprising an electrode 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 applied to the current collector plate in the active material application step. A method for producing an electrode for a secondary battery, wherein the material layer is applied in a plurality of times so as to form a plurality of layers, and the active material layer on the most surface side is applied intermittently.   The method for manufacturing an electrode for a secondary battery according to claim 7, wherein the application of the active material layer on the most surface side is performed using a transfer roller.