JP2017033667A - Manufacturing method of electrode sheet, and manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an electrode sheet by which the electrode sheet can be easily split from a belt-like mother sheet by utilizing a laser light.SOLUTION: The present invention relates to a manufacturing method of electrode sheets 8 and 9 with which an active material layer 3 containing an active material is formed on at least one region of a metal foil 2. According to the method, a belt-like mother sheet 1 is prepared which includes coating regions 1d and 1e where the active material layer 3 is formed on the belt-like metal foil 2, and exposed regions 1a, 1b and 1c in which the metal foil 2 is exposed. The mother sheet 1 is irradiated with a laser light along shapes of the electrode sheets 8 and 9. The exposed regions 1a, 1b and 1c are cut by the laser light and in the coating regions 1d and 1e, a notch 6 that does not penetrate in a thickness direction is formed by the laser light. A force is mechanically applied to the mother sheet 1, the mother sheet 1 is ruptured in a portion where the notch 6 is formed, and the electrode sheets 8 and 9 are split from the mother sheet 1.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for manufacturing an electrode sheet in which an active material layer containing an active material is formed on a metal foil. For example, the electrode sheet is a positive electrode sheet or a negative electrode sheet such as a lithium ion battery, and the positive electrode sheet and the negative electrode sheet are alternately stacked and inserted into the case.

  Secondary batteries such as lithium ion batteries or capacitors are widely used because they can be charged. For example, a secondary battery has positive electrode sheets and negative electrode sheets that are alternately stacked, and a sheet-like separator is interposed between the positive electrode sheet and the negative electrode sheet to avoid contact between them. The manufacturing method of a positive electrode sheet and a negative electrode sheet is disclosed by patent document 1, for example. According to this document, a strip-shaped metal foil is sequentially fed out and a paste-like active material mixture is applied onto the metal foil. The active material mixture is dried to form an active material layer on the metal foil to obtain a band-shaped mother sheet, and the mother sheet is wound around a roller. In the next step, the mother sheet is irradiated with laser light while being fed out of the roller, and the negative electrode sheet or the positive electrode sheet is separated from the mother sheet.

  The mother sheet has a coating region in which an active material layer is formed on a metal foil and an exposed region in which the metal foil is exposed without having an active material layer. Since the exposed region does not have an active material layer, the energy intensity of the laser beam necessary for cutting the exposed region is lower than the energy strength necessary for cutting the coating region. For this reason, if the energy intensity of the laser beam is increased to such an extent that both the exposed region and the coated region can be cut, the exposed region may melt the metal foil more than necessary, and the molten metal may remain in a lump. In order to avoid this, in Patent Document 1, the energy intensity of laser light is controlled for each region. That is, when cutting the exposed region, the energy intensity of the laser beam is lowered to avoid leaving a lump of metal. When cutting the coating region, the energy intensity of the laser beam is increased to such an extent that the coating region can be cut.

JP2012-221912A

  Therefore, in the conventional manufacturing method, the process of dividing the electrode sheet from the belt-shaped mother sheet has been complicated. Therefore, there is a need in the art for an electrode sheet manufacturing method that can easily divide an electrode sheet from a belt-shaped mother sheet using a laser beam.

  One embodiment of the present invention is a method for producing an electrode sheet in which an active material layer containing an active material is formed on at least one region of a metal foil. In this method, a belt-shaped mother sheet having a coating region where an active material layer is formed on a belt-shaped metal foil and an exposed region where the metal foil is exposed is prepared. The mother sheet is irradiated with laser light along the shape of the electrode sheet. The exposed area is cut by laser light, and a cut that does not penetrate through the coating area in the thickness direction is formed by the laser light. The electrode sheet is divided from the mother sheet by breaking the mother sheet at the portion where the notch is formed by applying mechanical force to the mother sheet.

  As described above, the coating region has an active material layer on the metal foil, and thus has a larger heat capacity than the exposed region. Therefore, the energy intensity of the laser beam necessary for cutting the coating region is higher than the energy intensity of the laser beam necessary for cutting the exposed region. On the other hand, in this method, a cut is formed in the coating region without cutting the coating region. Therefore, the energy intensity of the laser light applied to the coating area can be made lower than the energy intensity necessary for cutting the coating area. For example, the coating region is irradiated with laser light having a low energy intensity enough to cut the exposed region to form a cut in the coating region.

  As a result, there is no need to greatly change the energy intensity of the laser light in the exposed region and the coating region, and for example, the same can be achieved. Therefore, adjustment of the energy intensity of the laser beam becomes easy or unnecessary. Alternatively, it is not necessary to prepare each laser oscillator that transmits laser beams having different energy intensities. For example, the above manufacturing method can be performed by one laser oscillator. On the other hand, the coating region can be broken by a mechanical force in which a portion having a cut is smaller than other regions. Therefore, the coating region can be broken with a relatively small force by using the notch. Thus, the electrode sheet can be easily divided from the mother sheet.

  An electrode sheet manufacturing apparatus according to another embodiment of the present invention includes a conveying device, a laser processing machine, and a dividing device. The conveying device conveys a band-shaped mother sheet having a coating area where an active material layer is formed on a band-shaped metal foil and an exposed area where the metal foil is exposed. The laser processing machine irradiates the mother sheet on the transport device with laser light along the shape of the electrode sheet, cuts the exposed area with the laser light, and forms a cut that does not penetrate the coating area in the thickness direction with the laser light. To do. The dividing device breaks the mother sheet and divides the electrode sheet from the mother sheet at a portion where the cut is formed by mechanically applying force to the mother sheet.

  Therefore, the energy intensity of the laser light applied to the coating area can be made lower than the energy intensity necessary for cutting the coating area. For example, the coating region is irradiated with laser light having a low energy intensity enough to cut the exposed region to form a cut in the coating region. As a result, there is no need to greatly change the energy intensity of the laser light in the exposed region and the coating region, and for example, the same can be achieved. Then, the coating region is broken with a relatively small force by using a cut. Thus, the electrode sheet can be easily divided from the mother sheet.

It is a disassembled perspective view of a lithium ion battery. It is a flowchart of the manufacturing method of a lithium ion battery. It is a schematic side view of a coating drying apparatus. It is a schematic side view of the dividing device which divides a counter sheet from a mother sheet. It is a perspective view of a mother sheet passing through a laser beam machine and a laser beam machine. It is a top view of the mother sheet showing before and after laser processing. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. It is sectional drawing of the mother sheet | seat in the other form corresponding to FIG. It is sectional drawing of the mother sheet | seat in the other form corresponding to FIG. It is a schematic perspective view of the dividing device which divides a counter sheet from a mother sheet. It is a schematic plan view of a second dividing device that divides a counter sheet into first and second electrode sheets and a stocker that accommodates the stacked electrode sheets. It is a side view of the 2nd division | segmentation apparatus which divides | segments a counter sheet | seat into the 1st and 2nd electrode sheet | seat. It is a side view of the 2nd division | segmentation apparatus which divides | segments a counter sheet | seat into the 1st and 2nd electrode sheet | seat. It is a side view of the 2nd division | segmentation apparatus which divides | segments a counter sheet | seat into the 1st and 2nd electrode sheet | seat. It is a side view for showing a mode that an electrode sheet is laminated. It is a schematic side view of the division | segmentation apparatus in another form. It is a top view of the 2nd division | segmentation apparatus in the other form which divides | segments a counter sheet | seat into the 1st and 2nd electrode sheet | seat. It is a top view of the 2nd division | segmentation apparatus in the other form which divides | segments a counter sheet | seat into 1st and 2nd electrode sheets. It is a perspective view of the mother sheet which passes the laser beam machine in other forms, and this laser beam machine. It is a partial top view of the mother sheet | seat in another form. It is a partial top view of the mother sheet | seat in another form. It is a partial top view of the mother sheet | seat in another form.

  One embodiment of the present invention will be described with reference to the drawings. The power storage device shown in FIG. 1 is, for example, a lithium ion battery 10 and is used as a battery for automobiles, computers, portable electronic devices, and the like. The lithium ion battery 10 includes an electrode assembly 11 accommodated in a case 15 and an electrolyte (electrolytic solution).

  As shown in FIG. 1, the case 15 includes a bottomed rectangular parallelepiped case body 16 and a flat lid 17 that closes an opening of the case body 16. Both the case body 16 and the lid 17 are made of metal, for example, stainless steel or aluminum. In order to extract electric power from the electrode assembly 11 accommodated in the case 15, a positive terminal 19 and a negative terminal 18 that penetrate the cover 17 are attached to the cover 17.

  As shown in FIG. 1, the electrode assembly 11 includes positive electrode sheets (electrode sheets) 13 and negative electrode sheets (electrode sheets) 12 that are alternately stacked. A sheet-like separator 14 is provided between the positive electrode sheet 13 and the negative electrode sheet 12 to prevent the positive electrode sheet 13 and the negative electrode sheet 12 from coming into contact with each other. The negative electrode sheet 12 has a metal foil and an active material layer formed on both surfaces of the metal foil. The metal foil is, for example, a copper foil, and has a shape including a rectangular main body 12a and a tab 12b extending from an end edge of the main body 12a. An active material layer for the negative electrode is provided over substantially the entire area of both surfaces of the metal foil of the main body 12a. The tab 12b is not provided with an active material layer, and the metal foil is exposed. As shown in FIG. 1, the tabs 12b of the negative electrode sheet 12 are overlapped with each other and connected to each other by welding or the like. The tab 12 b is connected to one end of the negative electrode terminal 18 located in the case 15.

  The positive electrode sheet 13 also has an active material layer formed on both surfaces of the metal foil and the metal foil. The metal foil is, for example, an aluminum foil, and has a shape including a rectangular main body portion 13a and a tab 13b extending from an end edge of the main body portion 13a. An active material layer for a positive electrode is provided over substantially the entire area of both surfaces of the metal foil of the main body portion 13a. The tab 13b is not provided with an active material layer, and the metal foil is exposed. As shown in FIG. 1, the tabs 13b of the positive electrode sheet 13 are overlapped and connected by welding or the like. The tab 13 b is connected to one end of the positive terminal 19 located in the case 15.

  As shown in FIG. 1, the separator 14 is positioned between the main body portion 13 a of the positive electrode sheet 13 and the main body portion 12 a of the negative electrode sheet 12, thereby preventing the positive electrode sheet 13 and the negative electrode sheet 12 from contacting each other. The separator 14 is a polymer film, for example, a polyolefin-based microporous polymer film. Therefore, the separator 14 holds the electrolyte in the pores and allows lithium ions to move between the positive electrode sheet 13 and the negative electrode sheet 12.

  Next, a method for producing the negative electrode sheet (electrode sheet) 12 will be described. The manufacturing method of the negative electrode sheet 12 has a kneading step S1 as shown in FIG. In the kneading step S1, an active material mixture is prepared by mixing an active material, a binder, and a solvent for forming an active material layer. You may mix a conductive support agent and a thickener in an active material mixture as needed. The active material is a carbon material such as coke, for example. The binder is, for example, a resin material such as a fluorine resin and a rubber emulsion. The solvent is water, an organic solvent, or the like. The active material mixture is mixed in a kneading machine at a predetermined rotational speed for a predetermined time to become a slurry or a paste.

  Next, the coating process S2, the drying process S3, and the pressing process S4 shown in FIG. 2 are performed using the coating drying apparatus 20 shown in FIG. The coating / drying apparatus 20 includes a feeder 21 having a roller 21a. The feeder 21 supplies the strip-shaped metal foil 2 wound around the roller 21a as the roller 21a rotates. The coating drying apparatus 20 includes a coating machine 22 that coats the active material mixture onto the metal foil 2, a dryer 23 that dries the active material mixture, and a press machine 24 that pressurizes the active material layer.

  The coating machine 22 shown in FIG. 3 has first and second slit dies 22a and 22b on both sides of the metal foil 2 in the thickness direction. In other words, the metal foil 2 passes between the first and second slit dies 22a and 22b. The first and second slit dies 22a and 22b have a discharge port for discharging the active material mixture, and continuously apply the active material mixture onto the metal foil 2 from the discharge port (coating step S2). .

  For example, as shown in FIGS. 5 and 6, two rows of active material layers 3 are formed on each surface of the metal foil 2. The active material layers 3 in each row extend on the metal foil 2 over substantially the entire length in the longitudinal direction, and have substantially the same width over the entire length. The coating machine 22 in this case includes two first slit dies 22a arranged in the horizontal direction and two second slit dies 22b arranged in the horizontal direction. Thus, the metal foil 2 has two rows of coating regions 1d and 1e where the active material layers 3 and 4 are formed, and three rows where the metal foil 2 is exposed without the active material layers 3 and 4. Exposed areas 1a, 1b and 1c are formed.

  As shown in FIG. 3, the dryer 23 has a passage through which the metal foil 2 penetrates and a warm air generator that generates wind at a predetermined temperature. A warm air machine is provided in the thickness direction of the metal foil 2, and a solvent is evaporated from the active material mixture coated on both surfaces of the metal foil 2 (drying process S3). Thereby, the active material layers 3 and 4 formed from the active material mixture are formed on the surface of the metal foil 2.

  As shown in FIG. 3, the press machine 24 includes press rollers 24 a provided on both sides in the thickness direction of the metal foil 2. The metal foil 2 passes between the two press rollers 24a, and the active material layers 3 and 4 are sandwiched and pressed by the press roller 24a (press step S4). As a result, the active material layers 3 and 4 are compressed to have a predetermined thickness, and the density of the active material layers 3 and 4 is increased. Thereby, the mother sheet 1 is formed.

  Thereafter, the mother sheet 1 is wound around the winder 26 while receiving tension from the tension applying device 25 as shown in FIG. The tension applying machine 25 has a plurality of rollers 25 a to 25 d arranged in a distributed manner in the longitudinal direction of the metal foil 2, and the rollers 25 a to 25 d are also dispersed in the thickness direction of the metal foil 2. Accordingly, the mother sheet 1 receives tension from the rollers 25a and 25d by passing through the suspended rollers 25a and 25d. This prevents the mother sheet 1 from being wrinkled. The winder 26 includes a roller 26 a that winds up the mother sheet 1, and the metal foil 2 is discharged from the feeder 21 when the roller 26 a winds the mother sheet 1.

  As described above, the belt-shaped mother sheet 1 is formed by using the coating and drying apparatus 20 shown in FIG. As shown in FIGS. 5 and 6, the mother sheet 1 has a strip-shaped metal foil 2 and active material layers 3 and 4 formed on both surfaces of the metal foil 2. The mother sheet 1 has coating areas 1d and 1e having the active material layers 3 and 4, and exposed areas 1a, 1b and 1c where the metal foil 2 is exposed without the coating areas 1d and 1e. In the coating regions 1 d and 1 e, active material layers 3 and 4 are formed on both surfaces of the metal foil 2. The coating areas 1d, 1e and the exposed areas 1a, 1b, 1c are continuously formed in the longitudinal direction over the entire length of the metal foil 2.

  The mother sheet 1 has, for example, two rows of coating regions 1d and 1e and three rows of exposed regions 1a, 1b, and 1c as shown in FIGS. The width of the coating regions 1d and 1e corresponds to a size including the main body portions 8a and 9a of the two electrode sheets 8 and 9 (for example, the negative electrode sheet 12). The exposed region 1a and the exposed region 1c extend along the edge in the width direction of the mother sheet 1 and have a width corresponding to the length of the tabs 8b and 9b. The exposed region 1b located between the coating regions 1d and 1e also has a width corresponding to the length of the tabs 8b and 9b, and both the tab 8b and the tab 9b are arranged at predetermined intervals in the longitudinal direction as will be described later. .

  The mother sheet 1 wound on the winder 26 in FIG. 3 is put into a decompression chamber (not shown). In the decompression chamber, an environment having a pressure lower than the atmospheric pressure and a temperature higher than the atmospheric temperature is formed. Therefore, the solvent remaining in the coating regions 1d and 1e is volatilized in the decompression chamber, and the binder is cured (reduced pressure drying step S5).

  Thereafter, as shown in FIG. 4, the mother sheet 1 wound around the roller 31 a is set in the laser processing machine 35. As shown in FIG. 5, the laser processing machine 35 includes a first conveying device 32 that conveys the mother sheet 1 and a scanner 37 that emits laser light toward the mother sheet 1. The first transport device 32 includes a pair of rollers 32a and a belt 32b stretched around the rollers 32a. The mother sheet 1 is installed on the belt 32b, and the mother sheet 1 is conveyed and pulled out while receiving a predetermined tension from the roller 31a.

  As shown in FIG. 5, the scanner 37 is mounted on the base 36 and is positioned above the first transport device 32. The base 36 includes a column 36a that stands on both the left and right sides of the first transfer device 32, and a beam 36b that straddles the upper portion of the column 36a. Two scanners 37 are attached to the beam 36b, and each scanner 37 is positioned above the coating areas 1d and 1e. A laser oscillator 38 that oscillates laser light is connected to each scanner 37. The scanner 37 and the laser oscillator 38 are connected to a controller 39 that controls them.

  The laser oscillator 38 oscillates a pulsed laser beam, for example. The wavelength of the pulse wave is, for example, 1000 to 1100 nm, the frequency is 200 kHz, the output is 25 W, and can be changed within a predetermined range. The laser oscillator 38 oscillates laser light having a predetermined frequency and a predetermined output for a predetermined time based on a command signal from the controller 39.

  The scanner 37 irradiates a predetermined position of the mother sheet 1 with laser light by controlling the irradiation direction of the laser light. For example, the scanner 37 includes two mirrors, two drive devices that three-dimensionally change the angle of each mirror, and a condenser lens. The angle of each mirror is changed by each driving device, the pulse wave laser beam is reflected by two mirrors, and the laser beam is condensed by a condenser lens. In the controller 39 or the scanner 37, the change pattern and speed of the mirror angle by the driving device are stored in advance for each transport speed. Therefore, the scanner 37 emits laser light based on a command signal from the controller 39, and the laser light is emitted to the mother sheet 1 so as to correspond to the outer peripheral shape of the electrode sheets 8 and 9.

  The controller 39 includes, for example, a memory such as a CPU [Central Processing Unit], a ROM [Read Only Memory], and a RAM [Random Access Memory], an input / output circuit, and the like. The controller 39 may be incorporated as one function of the control device for the electrode production line, or may be a control device dedicated to the laser processing machine 35. The controller 39 receives speed information for the first conveying device 32 to convey the mother sheet 1. For example, a rotary encoder is provided on the roller 31 a of the supply machine 31, the conveyance speed is calculated based on a detection signal from the rotary encoder, and the speed information is input to the controller 39. When conveyance of the mother sheet 1 is started, the laser oscillator 38 oscillates laser light based on a signal from the controller 39. The scanner 37 adjusts the irradiation direction of the laser light according to the conveyance speed.

  As shown in FIG. 7, the laser light melts the metal foil 2 in the exposed region 1a and cuts the exposed region 1a. In the coating region 1d, a cut 6 is formed by laser light as shown in FIG. For example, the energy intensity of the laser beam is strong enough to melt the metal foil 2 and the active material layer 3 formed on one side surface of the metal foil 2, but not to melt the active material layer 4 formed on the other side surface. Adjusted. Therefore, the active material layer 4 formed on the other side surface of the metal foil 2 is not melted by the laser beam, and at least a part of the active material layer 4 in the thickness direction remains. Accordingly, a cut (groove) 6 that is not cut in the thickness direction by the laser beam is formed in the coating region 1d.

  The notch 6 may have a depth shown in FIG. 7 or may have a depth shown in FIGS. The cut 6 c shown in FIG. 8 penetrates the active material layer 3 formed on one side surface of the metal foil 2 and melts at least a part of the metal foil 2. On the other hand, the active material layer 4 formed on the other side surface of the metal foil 2 is not melted by the laser beam. The notch 6d shown in FIG. 9 melts at least a part of the active material layer 3 formed on one side surface of the metal foil 2. On the other hand, the active material layer 4 formed on the metal foil 2 and the other side surface of the metal foil 2 is not melted by the laser beam. None of the notches 6 shown in FIGS. 7, 8, and 9 penetrates the coating region 1d in the thickness direction.

  The energy intensity of the laser light may be controlled so as to be different between the case where it is irradiated to the exposed region 1a and the case where it is irradiated to the coating region 1d, or may be controlled so as to be substantially the same. When the energy intensity of the laser beam is substantially the same regardless of the region, the laser oscillator 38 can be easily controlled. For example, it is not necessary to change the frequency of the laser oscillator 38 in the exposed region 1a and the coating region 1d. Or the scanning speed of the laser beam by the scanner 37 can be made substantially the same in the exposure area | region 1a and the coating area | region 1d. This eliminates the need to change the scanning speed of the laser beam by the scanner 37.

  When the mother sheet 1 is laser processed, the mother sheet 1 is moved by a predetermined amount by the conveying device 32 based on a command signal from the controller 39 and stopped as shown in FIG. Next, a laser is emitted from the laser oscillator 38 based on a command signal from the controller 39 shown in FIG. 5, and the irradiation direction of the laser light by the scanner 37 is controlled. Thereby, the laser beam is irradiated onto the mother sheet 1 along the shape of the electrode sheets 8 and 9.

  As shown in FIG. 6, the laser light applied to the exposed areas 1a, 1b, 1c cuts the exposed areas 1a, 1b, 1c. On the other hand, the laser light applied to the coating regions 1d and 1e forms a cut 6 in the coating regions 1d and 1e. In the exposed regions 1a, 1b and 1c, the laser beam is irradiated along the first cutting lines 5a and 5c along the shape of the tabs 8b and 9b and the second cutting lines 5b and 5d along the edges of the main body portions 8a and 9a. Is done. Specifically, the second cutting line 5b extends along the edge of the main body 8a, 9a where the tabs 8b, 9b are provided, or along the boundary line between the exposed regions 1a, 1b, 1c and the coating regions 1d, 1e. Extend.

  As shown in FIGS. 5 and 6, in the coating regions 1d and 1e, a first cut (first cut line) 6a and a second cut (second cut line) 6b are formed by laser light. The first cut 6 a extends in the longitudinal direction at the approximate center in the width direction of the mother sheet 1. Thereby, the 1st notch 6a is extended along the boundary line of the main-body parts 8a and 9a of the electrode sheets 8 and 9 adjacent to the width direction. The second cut 6b crosses the mother sheet 1 in the width direction. Thereby, the 2nd notch 6b is extended along the boundary line of the main-body parts 8a and 9a of the electrode sheets 8 and 9 adjacent to a longitudinal direction.

  As shown in FIG. 6, the mother sheet 1 is irradiated with laser light so that four electrode sheets 8 and 9 are formed side by side in the width direction. The coating regions 1d and 1e are irradiated with laser light so that the two electrode sheets 8 and 9 are adjacent to each other in the width direction and the plurality of electrode sheets 8 and 9 are adjacent to each other in the longitudinal direction. Thus, the first cut 6a extends in the longitudinal direction at the center in the width direction of the coating regions 1d and 1e. The second cut 6b crosses the coating areas 1d and 1e in the width direction. The plurality of second cuts 6b are formed with a predetermined interval in the longitudinal direction.

  As shown in FIGS. 5 and 6, the exposed regions 1a, 1b, and 1c are irradiated with laser light so that the tabs 8b and 9b are arranged at predetermined intervals in the longitudinal direction. The exposed region 1b located between the coating regions 1d and 1e is irradiated with laser light so that the tabs 8b and 9b are alternately arranged in the longitudinal direction. Therefore, the width of the exposed region 1b has a length corresponding to one of the tabs 8b and 9b, and is narrower than the combined length of the two tabs 8b and 9b. Thereby, the area of the part discarded after dividing the electrode sheets 8 and 9 from the mother sheet 1 can be reduced. In order to prevent the tabs 8b and 9b from overlapping in the exposed region 1b, the electrode sheets 8 and 9 formed in the coating region 1d and the electrode sheets 8 and 9 formed in the coating region 1e are positioned in the longitudinal direction. It's off. For example, the misalignment has a length wider than the width of the tabs 8b and 9b.

  The mother sheet 1 subjected to laser processing is conveyed from the conveying device 32 to the second conveying device 33 as shown in FIGS. A dividing device 34 for dividing the counter sheet 7 from the mother sheet 1 is formed between the conveying device 32 and the second conveying device 33. The second transport device 33 is a belt conveyor and has a belt 33b stretched between rollers 33a. The belt 33 b of the second transport device 33 is set at a position lower than the belt 32 b of the transport device 32. Therefore, when the mother sheet 1 moves from the belt 32b to the belt 33b, the tip of the mother sheet 1 that has passed the belt 32b is pulled downward by its own weight. Therefore, a mechanical force is applied to the mother sheet 1, the force concentrates on the second cut 6b that is easier to break than other regions, and the mother sheet 1 is divided at the second cut 6b. Thus, the counter sheet 7 is divided or split from the mother sheet 1.

  As shown in FIGS. 4 and 10, the second transfer device 33 has a higher transfer speed than the transfer device 32. Therefore, when the leading edge of the mother sheet 1 comes into contact with the second conveying device 33, the leading edge of the mother sheet 1 is pulled by the belt 33 b of the second conveying device 33. Therefore, a mechanical force is applied to the mother sheet 1, the mother sheet 1 is divided at the second cut 6b, and the counter sheet 7 is divided from the mother sheet 1. Since the second conveying device 33 has a higher conveying speed than the conveying device 32, the counter sheet 7 divided from the mother sheet 1 is arranged on the belt 33b with a gap.

  As shown in FIG. 10, when the counter sheet 7 is divided from the mother sheet 1, portions other than the tabs 8b, 9b of the exposed regions 1a, 1b, 1c remain. As shown in FIG. 4, the remaining portion passes between the conveying devices 32 and 33 and is collected in a collection box 28 or the like installed below the conveying devices 32 and 33.

  As shown in FIG. 10, the counter sheet 7 is continuously divided from the mother sheet 1. As described above, both side edges of the counter sheet 7 are located in the exposed regions 1 a, 1 b, 1 c, and both side edges are cut by the laser processing machine 35. The boundary between the counter sheets 7 is located in the coating areas 1d and 1e, and a cut (groove) 6 is formed by the laser processing machine 35 at the boundary. The portion having the cut 6 is broken by applying a force to the mother sheet 1 by the dividing device 34. Thereby, the counter sheet 7 is divided from the mother sheet 1. The counter sheet 7 includes two electrode sheets 8 and 9, and the two electrode sheets 8 and 9 are connected via the second notch 6 b.

  As shown in FIG. 10, the counter sheet 7 is divided from the mother sheet 1, and the counter sheet 7 is aligned in two rows on the second conveying device 33. The counter sheet 7 is transported by the second transport device 33. For example, one row of the counter sheets 7 is transferred to the third transport device 30 shown in FIG. Accordingly, the counter sheet 7, that is, the electrode sheets 8 and 9 are conveyed in a connected state. Therefore, compared with the case where the electrode sheets 8 and 9 are divided and conveyed individually, the electrode sheets 8 and 9 can be easily conveyed.

  As shown in FIG. 11, the counter sheet 7 moves from the third conveying device 30 to the second dividing device 40. The second dividing device 40 includes a table 41 and two bars 42 installed on the table 41. The counter sheet 7 is positioned on the two bars 42 by moving from the third conveying device 30 to the table 41. The two bars 42 are substantially parallel to the second cut 6 b, and one bar 42 is located below one electrode sheet 8 and the other bar 42 is located below the other electrode sheet 9.

  As shown in FIG. 12, the intermediate plate 43 is installed above the first cut 6a. The intermediate plate 43 is carried by a robot or the like, for example, and is erected along the first cut 6a. As shown in FIGS. 13 and 14, the bar 42 is moved upward by a robot or the like. As a result, the electrode sheets 8 and 9 rise up with the first notch 6a facing down. When the electrode sheets 8 and 9 are raised, mechanical stress concentrates on the first cut 6a that is easier to break than the other portions, and the counter sheet 7 is broken at the first cut 6a.

  As shown in FIGS. 12 to 14, when the electrode sheets 8 and 9 are erected, the intermediate plate 43 hits the second cut 6 b, and mechanical force is applied to the first cut 6 a using the intermediate plate 43. Alternatively, when the electrode sheets 8 and 9 are erected, the counter sheet 7 is divided at the first cut 6a only by its own weight. After the electrode sheets 8 and 9 are erected, the bar 42 is moved above the electrode sheets 8 and 9 to retract the bar 42 from the electrode sheets 8 and 9. An intermediate plate 43 is located between the standing electrode sheets 8 and 9.

  As shown in FIG. 11, the facing sheet 7 has a symmetrical shape with the first cut 6 a as the center. The counter sheet 7 has tabs 8b and 9b at symmetrical positions around the first cut 6a. Therefore, the counter sheet 7 is bent so that the electrode sheets 8 and 9 face each other, so that the first sheet 6 is broken at the first cut 6a and the tabs 8b and 9b face each other. Therefore, the tabs 8b and 9b are overlapped in the thickness direction.

  As shown in FIG. 15, another intermediate plate 43 is prepared on the outer surfaces of the electrode sheets 8 and 9 erected, for example, using a short axis robot. The other intermediate plate 43 faces the electrode sheet 9 in an upright state, and pushes the electrode sheets 8 and 9 toward the stopper 44 by a short-axis robot or the like. As a result, the electrode sheets 8 and 9 move from the first position to the second position, and stand on the stopper 44 at the second position. Subsequently, as shown in FIG. 11, the other counter sheet 7 is moved to the first position, and the electrode sheets 8 and 9 are divided from the counter sheet 7 to stand. Then, the standing electrode sheets 8 and 9 are moved toward the second position so as to overlap the electrode sheets 8 and 9 that have been moved to the second position first. Accordingly, the electrode sheets 8 and 9 are stacked in the thickness direction, and the intermediate plate 43 is positioned between the electrode sheets 8 and 9.

  As shown in FIG. 11, when the number of stacked electrode sheets 8 and 9 reaches a predetermined number, the moving device 53 moves the electrode sheets 8 and 9 and the intermediate plate 43 to the stocker 50. For example, a predetermined number of electrode sheets 8 and 9 are moved to the stocker 50 by controlling the short axis robot and the moving device 53 by a controller (not shown). The stocker 50 has a partition 51 and a storage portion 52 between the partitions 51. The electrode sheets 8 and 9 are stored in the storage portion 52, and the electrode sheets 8 and 9 are conveyed together with the partition 51. Instead of the partition 51, a box or the like for receiving the electrode sheets 8 and 9 may be used.

  As described above, the electrode sheets 8 and 9 divided from the mother sheet 1 are, for example, the negative electrode sheet 12. The plurality of negative electrode sheets 12 are stacked and accommodated in the stocker 50. The positive electrode sheet 13 is also formed from the positive electrode mother sheet 1 in the same manner as the negative electrode sheet 12.

  That is, in the kneading step S1, the electrode material for the positive electrode is mixed by a kneader. The electrode material includes at least an active material, a binder, and a solvent, and includes a conductive additive and a thickener as necessary. The active material is, for example, metallic lithium such as lithium cobaltate, lithium manganate, lithium nickelate, or lithium titanate. As the binder, the solvent, the conductive additive, and the thickener, the same materials as those of the negative electrode described above can be used.

  Next, the coating process S2, the drying process S3, and the pressing process S4 are performed using the coating drying apparatus 20 shown in FIG. In the coating step S2, the metal foil 2 for positive electrode is supplied from the roller 21a. The metal foil 2 of the positive electrode is, for example, an aluminum foil. In the drying step S <b> 3, the solvent is evaporated from the active material mixture coated on the metal foil 2 using the dryer 23. Thereby, the active material layers 3 and 4 formed from the active material mixture are formed on both surfaces of the metal foil 2. In the pressing step S4, the active material layers 3 and 4 are pressurized using the pressing machine 24 shown in FIG. Thereby, the base sheet 1 for positive electrodes is formed. Thereafter, the mother sheet 1 is wound around the winder 26 while being tensioned by the tensioner 25.

  The positive electrode mother sheet 1 is also put into the vacuum chamber in the vacuum drying step S5. In the decompression chamber, the pressure is lower than the atmospheric pressure and the temperature is raised above the atmospheric temperature. As a result, the solvent in the coating areas 1d and 1e is volatilized and the binder is cured. The positive electrode mother sheet 1 is also subjected to laser processing in the same manner as the negative electrode mother sheet 1 using the laser processing machine 35 shown in FIG. 5 (laser processing step S6).

  The exposed regions 1a, 1b, 1c are cut in the thickness direction at the first cutting lines 5a, 5c and the second cutting lines 5b, 5d. The first cutting lines 5a and 5c extend along the outer peripheries of the tabs 8b and 9b of the electrode sheets 8 and 9, respectively. The second cutting lines 5b and 5d extend along the edges of the main body portions 8a and 9a having the tabs 8b and 9b. A first cut 6a and a second cut 6b are formed in the coating regions 1d and 1e. The first cut 6 a extends in the longitudinal direction so as to extend between the electrode sheets 8 and 9 adjacent in the width direction of the mother sheet 1. The second cut 6b extends in the width direction so as to extend between the electrode sheets 8 and 9 adjacent in the longitudinal direction.

  Next, as shown in FIG. 10, the counter sheet 7 is formed from the positive electrode mother sheet 1 using the dividing device 34. The dividing device 34 applies a mechanical force to the second cuts 6b by using the weight of the mother sheet 1. Thereby, the mother sheet 1 is cut at the second cut 6b, and the counter sheet 7 is divided from the mother sheet 1 (dividing step S7). Next, the counter sheet 7 is conveyed using the second conveying device 33 and the third conveying device 30 (conveying step S8). Therefore, the electrode sheets 8 and 9 are conveyed integrally as a counter sheet 7 in a state of being connected by the second cut 6b.

  Next, as shown in FIG. 11, a mechanical force is applied to the positive pair sheet 7 by the second dividing device 40, and the pair sheet 7 is cut at the first cut 6a. Thus, the electrode sheets 8 and 9 are divided from the counter sheet 7 (dividing step S9). Next, as shown in FIG. 15, the positive electrode sheets 8 and 9 are moved up together with the intermediate plate 43 toward the stopper 44. Similarly, the electrode sheets 8 and 9 are divided from the other counter sheet 7, and the electrode sheets 8 and 9 from the other counter sheet 7 are overlapped on the electrode sheets 8 and 9 that have been previously stood on the stopper 44. When the number of the stacked electrode sheets 8 and 9 reaches a predetermined amount, the electrode sheets 8 and 9 are moved to the stocker 50 (stacking step S10).

  As described above, the plurality of negative electrode sheets 12 (electrode sheets 8 and 9) are stacked with the intermediate plate 43 therebetween. The plurality of positive electrode sheets 13 (electrode sheets 8 and 9) are also stacked with the intermediate plate 43 therebetween. The edge of the positive electrode sheet 13 is inserted between the negative electrode sheets 12 using the gap formed by the intermediate plate 43. Similarly, the edge of the separator 14 is inserted between the negative electrode sheet 12 and the positive electrode sheet 13. Then, while removing the intermediate plate 43, the two separators 14 and the positive electrode sheet 13 positioned between the two separators are inserted between the negative electrode sheets 12.

  As shown in FIG. 1, the tab 12b of the negative electrode sheet 12 and the tab 13b of the positive electrode sheet 13 are both located at one end edge (upper edge) in FIG. The negative tab 12b is positioned in one region in the width direction (for example, the left region in FIG. 1), and the positive tab 13b is positioned in another region in the width direction (for example, the right region in FIG. 1). The negative tabs 12b are connected to each other, and the positive tabs 13b are connected to each other. Thereby, the electrode assembly 11 shown in FIG. 1 is formed. The tab 12 b is connected to one end of the negative electrode terminal 18, the tab 13 b is connected to one end of the positive electrode terminal 19, and the electrode assembly 11 is inserted into the case 15. Then, the electrode assembly 11 and the electrolyte are sealed in the case 15 (case sealing step S11). Thereby, the lithium ion battery 10 which is one of the power storage devices is formed.

  As described above, the present embodiment relates to a method for manufacturing electrode sheets 8 and 9 in which an active material layer 3 containing an active material is formed on at least one region of a metal foil 2 as shown in FIGS. In this method, a strip-shaped base sheet 1 having coating regions 1d and 1e in which active material layers 3 and 4 are formed on a strip-shaped metal foil 2 and exposed regions 1a, 1b and 1c in which the metal foil 2 is exposed is obtained. prepare. The mother sheet 1 is irradiated with laser light along the shape of the electrode sheets 8 and 9. The exposed regions 1a, 1b, and 1c are cut by the laser beam, and the notches 6 that do not penetrate in the thickness direction are formed in the coating regions 1d and 1e by the laser beam. The base sheet 1 is broken at a portion where the notch 6 is formed by mechanically applying force to the base sheet 1 to divide the electrode sheets 8 and 9 from the base sheet 1.

  As described above, since the coating regions 1d and 1e have the active material layers 3 and 4 on the metal foil 2, they have a larger heat capacity than the exposed regions 1a, 1b and 1c. Therefore, the energy intensity of the laser beam necessary for cutting the coating regions 1d, 1e is higher than the energy intensity of the laser beam necessary for cutting the exposed regions 1a, 1b, 1c. On the other hand, in this method, the notch 6 is formed in the coating regions 1d and 1e without cutting the coating regions 1d and 1e. Therefore, the energy intensity of the laser light applied to the coating areas 1d and 1e can be made lower than the energy intensity necessary for cutting the coating areas 1d and 1e. For example, the application regions 1d and 1e are irradiated with laser light having a low energy intensity to cut the exposed regions 1a, 1b, and 1c to form the cuts 6 in the application regions 1d and 1e.

  As a result, it is not necessary to largely change the energy intensity of the laser light in the exposed regions 1a, 1b, 1c and the coating regions 1d, 1e, and for example, they can be the same. Therefore, adjustment of the energy intensity of the laser beam becomes easy or unnecessary. Alternatively, it is not necessary to prepare each laser oscillator 38 that transmits laser beams having different energy intensities. For example, the above-described manufacturing method can be achieved with one laser oscillator 38. On the other hand, in the coating regions 1d and 1e, the portion having the cut 6 can be broken by a mechanical force smaller than the other regions. Therefore, the coating areas 1d and 1e can be broken with a relatively small force by using the notch 6. Thereby, the electrode sheets 8 and 9 can be easily divided from the mother sheet 1.

  As shown in FIG. 5, the mother sheet 1 is adjacent to the first exposed region 1a adjacent to the first end 1g of the coating region 1d and the second end 1h of the coating region 1d opposite to the first end 1g. A second exposed region 1b is provided. The first electrode sheet 8 including the first tab 8b formed from the first exposed region 1a and the second electrode sheet 9 including the second tab 9b formed from the second exposed region 1b are adjacent to each other. The mother sheet 1 is irradiated with laser light along the shapes of the sheet 8 and the second electrode sheet 9. The first electrode sheet 8 and the second electrode sheet 9 have body portions 8a and 9a, respectively, in the coating region 1d. The first electrode sheet 8 and the second electrode at a place different from the first notch 6a in the coating region 1d and the first notch 6a along the boundary between the main body portions 8a and 9a of the first electrode sheet 8 and the second electrode sheet 9. A second notch 6b is formed along the shape of the main body portions 8a, 9a of the sheet 9. Mechanical force is applied to the mother sheet 1 to break the mother sheet 1 at the second cut 6b, and the counter sheet 7 including the first electrode sheet 8 and the second electrode sheet 9 connected by the first cut 6a is used as the mother sheet. The sheet 1 is divided. The counter sheet 7 is conveyed. A mechanical force is applied to the counter sheet 7 to break the counter sheet 7 at the first notch 6 a to divide the counter sheet 7 into a first electrode sheet 8 and a second electrode sheet 9.

  Therefore, in the above-described manufacturing method, the counter sheet 7 is divided from the mother sheet 1, and the first electrode sheet 8 and the second electrode sheet 9 are integrally conveyed as the counter sheet 7. Therefore, the 1st electrode sheet 8 and the 2nd electrode sheet 9 can be conveyed to the following process more simply than the case where the 1st electrode sheet 8 and the 2nd electrode sheet 9 are conveyed separately. Alternatively, since the first electrode sheet 8 and the second electrode sheet 9 are divided after being conveyed as the counter sheet 7, the relative positions of the first electrode sheet 8 and the second electrode sheet 9 are accurately or easily determined at the time of division. obtain.

  As shown in FIG. 11, in the manufacturing method, the first tab 8b and the second tab 8b are formed so as to be symmetrical with respect to the first cut 6a. The facing sheet 7 is bent at the first notch 6a so that the first tab 8b and the second tab 8b face each other. Then, the counter sheet is broken at the first notch 6a to divide the counter sheet 7 into a first electrode sheet 8 and a second electrode sheet 9, and the first tab 8b and the second tab 9b face each other and the first electrode The sheet 8 and the second electrode sheet 9 face each other.

  Therefore, since the first electrode sheet 8 and the second electrode sheet 9 are formed from the counter sheet 7, they have the same polarity, for example, both positive or negative polarity. As shown in FIG. 1, the electrode sheets 8 and 9 having the same polarity are stacked so that the tabs 8 b and 9 b are overlapped with each other, and are connected to electrode terminals that penetrate the lid 17 of the case 15, for example, one end of the positive terminal 19 and the negative terminal 18. Is done. Conventionally, the electrode sheets 8 and 9 having the same polarity have a step of overlapping while aligning the directions so that the tabs 8b and 9b overlap. In this method, the first electrode sheet 8 and the second electrode sheet 9 are divided by one step of bending the counter sheet 7, and the first tab 8b and the second tab 9b are overlapped. Therefore, the counter sheet 7 can be divided and the tabs 8b and 9b can be overlapped in one process.

  As shown in FIGS. 12 and 14, in the manufacturing method, both sides of the counter sheet 7 which are symmetrical with respect to the first cut 6a are lifted. Thereby, the counter sheet 7 is broken at the portion having the first cuts 6 a to divide the counter sheet 7 into the first electrode sheet 8 and the second electrode sheet 9. Then, the first electrode sheet 8 and the second electrode sheet 9 are erected with the edge corresponding to the first notch 6a as the lower side. Accordingly, since the electrode sheets 8 and 9 are erected, they can be easily moved as compared with the case where the electrode sheets 8 and 9 are stacked in the thickness direction in a collapsed state. For example, the positive electrode sheet 13 and the negative electrode sheet 12 can be stacked alternately easily or in a short time.

  As shown in FIGS. 12 to 15, in the manufacturing method, the upright first electrode sheet 8 and second electrode sheet 9 are pushed in the thickness direction to move from the first position to the second position and rest on the stopper 44. Similarly, the second pair sheet 7 is moved to the first position to lift both sides of the second pair sheet 7. As a result, the second pair sheet 7 is broken at the first cut 6a, divided into two electrode sheets 8, 9 and moved up to the second position, and the electrode sheet 8, moved to the second position first, 9, the electrode sheets 8 and 9 of the second pair sheet 7 are overlapped.

  Accordingly, the electrode sheets 8 and 9 are moved upright and overlapped in the thickness direction. Therefore, a conventionally required process, for example, a process of changing the height, such as lifting the electrode sheets 8 and 9 in a collapsed state and placing them on the other electrode sheets 8 and 9, becomes unnecessary. In contrast, in this method, the electrode sheets 8 and 9 can be stacked in the thickness direction without changing the height of the electrode sheets 8 and 9. That is, the electrode sheets 8 and 9 can be stacked in the thickness direction in an upright state without lifting the electrode sheets 8 and 9.

  As shown in FIG. 12, in this method, the intermediate plate 43 is set at a position corresponding to the first cut 6a. The intermediate plate 43 is positioned between the first electrode sheet 8 and the second electrode sheet 9 by bending the counter sheet 7 at the first cut 6 a. A third electrode sheet is inserted between the first electrode sheet 8 and the second electrode sheet 9 while removing the intermediate plate 43 from between the first electrode sheet 8 and the second electrode sheet 9. For example, the positive electrode sheet 13 is inserted between the negative electrode sheets 12, or the negative electrode sheet 12 is inserted between the positive electrode sheets 13.

  Therefore, since the first electrode sheet 8 and the second electrode sheet 9 are formed from the same counter sheet 7, they have the same polarity, for example, both positive or negative polarity. The intermediate plate 43 is located between the first electrode sheet 8 and the second electrode sheet 9 and forms a space for inserting the third electrode sheet. Therefore, by using the intermediate plate 43, for example, the positive electrode sheet 13 can be inserted between the negative electrode sheets 12.

  As shown in FIG. 6, the exposed region 1b is located between the two rows of coating regions 1d and 1e. In the exposed region 1b, tabs 9b and tabs 8b are alternately arranged in the longitudinal direction. The tab 9b is a tab of the electrode sheet 9 formed from the coating region 1d, and the tab 8b is a tab of the electrode sheet 8 formed from the other coating region 1e. Therefore, compared to the case where the width of the exposed region 1b is increased so that the tabs 8b and 9b are arranged in the width direction, the discarded area is reduced. Thus, material costs can be reduced.

  As shown in FIG. 5, the first cut 6a and the second cut 6b are formed in the mother sheet 1 by laser processing. The portion having the second cut 6b of the mother sheet 1 is broken by receiving a force in the dividing device 34 shown in FIG. The portion having the first cut 6a of the mother sheet 1 (counter sheet 7) is broken by receiving a force in the second dividing device 40 shown in FIG. 12 and receiving a force larger than the other portions. That is, the mother sheet 1 is divided into electrode sheets 8 and 9 in three stages.

  As shown in FIG. 5, the laser beam machine 35 irradiates the exposed areas 1a, 1b, 1c and the coating areas 1d, 1e with laser light having substantially the same energy intensity. At this time, the energy intensity of the laser beam is set to such a level that the coating regions 1d and 1e are not cut, that is, a cut is formed in the coating regions 1d and 1e. Accordingly, it is possible to avoid problems caused by irradiating the exposed regions 1a, 1b, and 1c with laser light having a high energy intensity so that the coating regions 1d and 1e are cut. That is, the amount of the metal foil 2 in which the exposed regions 1a, 1b, and 1c are melted by the laser light increases, and the problem that the melted metal foil remains in a lump can be reduced.

  As shown in FIG. 5, the laser beam machine 35 irradiates the exposed areas 1a, 1b, 1c and the coating areas 1d, 1e with laser light having substantially the same energy intensity. Therefore, complicated control of changing the energy intensity of the laser beam in the exposed regions 1a, 1b, 1c and the coating regions 1d, 1e is not necessary. Alternatively, it is not necessary to prepare a plurality of laser oscillators 38 that transmit each energy intensity in order to transmit laser beams having different energy intensity. Thereby, the laser processing machine 35 can be made inexpensive.

  As shown in FIGS. 5 and 10, the manufacturing apparatus for the electrode sheets 8 and 9 includes a conveying device 32, a laser processing machine 35, and a dividing device 34. The conveying device 32 conveys the belt-shaped mother sheet 1 having the coating regions 1d and 1e where the active material layer 3 is formed on the belt-shaped metal foil 2 and the exposed regions 1a, 1b and 1c where the metal foil 2 is exposed. To do. The laser processing machine 35 irradiates the mother sheet 1 on the conveying device 32 with laser light along the shape of the electrode sheets 8, 9, cuts the exposed areas 1 a, 1 b, 1 c with the laser light, and coats with the laser light. Cuts 6 that do not penetrate in the thickness direction are formed in the work areas 1d and 1e. The dividing device 34 breaks the mother sheet 1 and divides the electrode sheets 8 and 9 from the mother sheet 1 at a portion where a cut is formed by mechanically applying force to the mother sheet 1.

  As shown in FIGS. 4 and 10, the dividing device 34 includes a second transport device 33 that is positioned downstream of the transport device 32 and positioned below the transport device 32. A force is mechanically applied to the mother sheet 1 using gravity received when the leading edge of the mother sheet 1 falls from the conveying device 32 to the second conveying device 33. Therefore, the dividing device 34 is configured to use gravity by the conveying device 32 and the second conveying device 33 having different heights. Therefore, the dividing device 34 can be configured relatively easily.

  As shown in FIGS. 4 and 10, the dividing device 34 includes a second transport device 33 that is located downstream of the transport device 32 and has a transport speed higher than that of the transport device 32. When the leading edge of the mother sheet 1 reaches the second conveying device 33 from the conveying device 32, the second conveying device 33 mechanically applies a force to the mother sheet 1 by pulling the leading edge of the mother sheet 1. Therefore, the dividing device 34 uses the transport device 32 and the second transport device 33 having different transport speeds. Therefore, it is possible to make the dividing device 34 have a relatively small configuration, for example, a small configuration in the vertical direction.

  Although the embodiments of the present invention have been described with reference to the above structure, it will be apparent to those skilled in the art that many alternations, modifications, and changes can be made without departing from the scope of the present invention. Accordingly, aspects of the invention may include all alterations, modifications, and changes that do not depart from the spirit and scope of the appended claims. For example, the form of the present invention is not limited to the special structure, and can be modified as follows.

  In the method described above, the dividing sheet 34 shown in FIGS. 4 and 10 is used to break the mother sheet 1 at the second cut 6b and divide the counter sheet 7 from the mother sheet 1. Instead of this, the mother sheet 1 may be broken at the second cut 6b using the dividing device 60 shown in FIG. The dividing device 60 illustrated in FIG. 16 includes a transport device that is arranged continuously with the transport device 32. The conveying device has, for example, a roller 60a and a belt 60b stretched between the rollers 60a. The belt 60 b of the dividing device 60 is installed at substantially the same height as the belt 32 b of the transport device 32. The dividing device 60 can be transported at a speed higher than that of the transport device 32. For example, the speed of the belt 60b is faster than that of the belt 32b. Therefore, when the leading edge of the mother sheet 1 moves from the conveying device 32 to the dividing device 60, the leading edge of the mother sheet 1 is pulled with respect to other portions. As a result, the mother sheet 1 receives mechanical force and breaks at the second notch 6 b, and the counter sheet 7 is divided from the mother sheet 1.

  In the above method, the counter sheet 7 is broken at the first notch 6a using the second dividing device 40 shown in FIGS. Instead, by using the dividing device 61 shown in FIG. 17 or the dividing device 70 shown in FIG. 18, the counter sheet 7 is broken at the first cut 6 a, and the electrode sheets 8 and 9 are divided from the counter sheet 7. May be. A dividing device 61 shown in FIG. 17 includes a first belt 61a having a width for conveying the counter sheet 7 and two second belts 61b and 61c branched from the downstream end of the first belt 61a. The second belts 61b and 61c extend from the first belt 61a while being spaced apart from each other in the horizontal direction.

  As shown in FIG. 17, the counter sheet 7 is conveyed from the first belt 61a to the second belts 61b and 61c. When the counter sheet 7 reaches the second belts 61b and 61c, the first electrode sheet 8 is pulled by the second belt 61b, and the second electrode sheet 9 is pulled by the second belt 61c. Accordingly, the counter sheet 7 is pulled so that the electrode sheets 8 and 9 are separated in the horizontal direction. Thus, the counter sheet 7 receives mechanical force and breaks at the first notch 6 a, and the counter sheet 7 is divided into electrode sheets 8 and 9.

  The belt 61a of the dividing device 61 shown in FIG. 17 has a plurality of strings extending in the longitudinal direction, and the plurality of strings are arranged in the width direction. A bundle of strings positioned on one end side of the belt 61a is arranged to extend from the belt 61a along the belt 61b. The bundle of strings positioned on the other end side of the belt 61a is arranged so as to extend along the other belt 61c from the belt 61a. Thus, the bundle of two strings is gathered together in the first half and separated from each other in the second half.

  The dividing device 61 shown in FIG. 17 may have a plurality of rollers instead of the belts 61a, 61b, 61c. The rollers are oriented such that the rotation shaft extends in the width direction of the belts 61a, 61b, 61c, and are arranged along the longitudinal direction of the belts 61a, 61b, 61c. That is, the counter sheet 7 is conveyed by a plurality of first rollers arranged in parallel with the longitudinal direction of the belt 61a. The plurality of second rollers arranged in parallel with the longitudinal direction of the belt 61b and the plurality of third rollers arranged in parallel with the longitudinal direction of the belt 61c are separated from each other. Therefore, the counter sheet 7 is pulled by the second roller and the third roller so that the electrode sheets 8 and 9 are separated from each other. Thus, the counter sheet 7 is divided into electrode sheets 8 and 9.

  18 includes a first belt 70a having a width for transporting the counter sheet 7, two second belts 70b and 70c branched from the downstream end of the first belt 70a, and a second belt. It has the 3rd belt 70d located in the downstream part where 70b and 70c merge. The second belts 70b and 70c extend from the first belt 70a while being spaced apart from each other in the vertical direction, and then extend toward the third belt 70d while being close to each other in the vertical direction.

  The upper second belt 70b includes an inclined belt 70e extending obliquely upward from one end in the width direction of the first belt 70a, a horizontal belt 70f extending horizontally from the tip of the inclined belt 70e, and the horizontal belt 70f. An inclined belt 70g extending downward from the tip is provided. The tip of the inclined belt 70g is adjacent to one end of the third belt 70d in the width direction. The lower second belt 70c includes an inclined belt 70h extending obliquely downward from the other widthwise end of the first belt 70a, a horizontal belt 70i extending horizontally from the tip of the inclined belt 70h, and a horizontal belt. An inclined belt 70j extending upward from the tip of 70i is provided. The tip of the inclined belt 70j is adjacent to the other end in the width direction of the third belt 70d.

  As shown in FIG. 18, the counter sheet 7 is conveyed from the first belt 70a to the second belts 70b and 70c. When the counter sheet 7 reaches the second belts 70b and 70c, the first electrode sheet 8 is pulled by the second belt 70b, and the second electrode sheet 9 is pulled by the second belt 70c. Accordingly, the counter sheet 7 is pulled so that the electrode sheets 8 and 9 are separated in the vertical direction. Thus, the counter sheet 7 receives mechanical force and breaks at the first notch 6 a, and the counter sheet 7 is divided into electrode sheets 8 and 9.

  18 may have a plurality of rollers instead of the belts 70a, 70b, 70c, and 70d. The rollers are oriented such that the rotation shaft extends in the width direction of the belts 70a, 70b, 70c, 70d, and are arranged along the longitudinal direction of the belts 70a, 70b, 70c, 70d.

  The electrode sheet manufacturing apparatus may have a laser processing machine 71 shown in FIG. 19 instead of the laser processing machine 35 shown in FIG. A laser processing machine 71 shown in FIG. 19 includes a first conveying device 32 and a laser head 73 that irradiates laser light toward the mother sheet 1. The laser head 73 is attached to the XY axis robot 72 and moves in the XY axis direction. For example, the XY axis robot 72 supports an X axis member 72 a that supports the laser head 73 so as to be movable in the X direction that is the width direction of the mother sheet 1, and an X axis member 72 a in the Y direction that is the longitudinal direction of the mother sheet 1. Has a Y-axis member 72b that movably supports it.

  As shown in FIG. 19, an assist gas supply device 76 for supplying an assist gas is connected to the laser head 73. Further, the laser head 73 is connected to a laser oscillator 74 that supplies a laser beam through a fiber cable. The laser oscillator 74 is connected to the controller 75, and the oscillation state of the laser beam is controlled by the function generator of the controller 75. Laser light supplied by the laser oscillator 74 is, for example, YAG laser light or CO2 laser light. The controller 75 is also connected to the XY axis robot 72 and moves the laser head 73 in accordance with a stored program.

  As shown in FIG. 19, the laser head 73 collects and irradiates the laser light supplied from the laser oscillator 74 and emits an assist gas. The laser light melts the metal foil 2 in the exposed region 1a and blows off the melted metal foil 2 by the assist gas sprayed coaxially with the beam. Thereby, the exposed region 1a is cut by the laser beam. In the coating region 1d, a cut 6 is formed by laser light. For example, the laser beam melts the metal foil 2 and the active material layer 3 formed on one side surface of the metal foil 2 and blows off with an assist gas. On the other hand, the active material layer 4 formed on the other side surface of the metal foil 2 is not melted by the laser beam, and at least one part in the thickness direction remains. Accordingly, a cut (groove) 6 that is not cut in the thickness direction by the laser beam is formed in the coating region 1d.

  A laser oscillator 38 shown in FIG. 5 oscillates a pulsed laser beam. Alternatively or in addition, the laser oscillator 38 may oscillate continuous wave laser light. The wavelength of the continuous wave laser beam is 1000 to 1100 nm, for example, and the output is 500 W.

  As shown in FIG. 6, the mother sheet 1 has two rows of coating regions 1d and 1e and three rows of exposed regions 1a, 1b, and 1c. Then, two electrode sheets 8 and 9 arranged in the width direction from the coating regions 1d and 1e in each row are formed. Instead of the mother sheet 1 shown in FIG. 6, the electrode sheets 8 and 9 may be divided from the mother sheet 62 shown in FIG. 20, the mother sheet 63 shown in FIG. 21, and the mother sheet 64 shown in FIG.

  As shown in FIG. 20, the mother sheet 62 has a row of coating regions 62b extending in the longitudinal direction and a row of exposed regions 62a extending in the longitudinal direction. The electrode sheet 65 formed from the mother sheet 62 has a rectangular main body portion 65a formed from the coating region 62b and a tab 65b protruding from the edge of the main body portion 65a. When the mother sheet 62 is laser processed by the laser processing machine 35 shown in FIG. 5 or the like, both the exposed region 62a and the coating region 62b are irradiated with laser light.

  As shown in FIG. 20, in the exposed region 62a, laser light is irradiated along a first cutting line 62c along the outer periphery of the tab 65b and a second cutting line 62d along the edge of the main body 65a having the tab 65b. . The exposed region 62a is cut at the first cutting line 62c and the second cutting line 62d by the laser light. In the coating region 62b, laser light is irradiated along the side edge of the main body portion 65a of the electrode sheet 65, and a cut 62e is formed. Then, by applying force to the mother sheet 62 using the dividing device 34 and the like of FIG. 10, the mother sheet 62 is broken at the notch 62e. Thereby, the electrode sheet 65 can be divided from the mother sheet 62.

  As shown in FIG. 21, the mother sheet 63 alternately has two rows of coating regions 63b and 63d extending in the longitudinal direction and two rows of exposed regions 63a and 63c extending in the longitudinal direction. Two rows of electrode sheets 66 and 67 are divided from the mother sheet 63. The electrode sheet 66 has a rectangular main body 66a formed from the coating region 63b, and a tab 66b formed from the exposed region 63a protruding from the edge of the main body 66a. The electrode sheet 67 has a rectangular main body portion 67a formed from the coating region 63d, and a tab 67b that protrudes from the edge of the main body portion 67a and is formed from the exposed region 63c. When the mother sheet 63 is laser processed by the laser processing machine 35 shown in FIG. 5 or the like, both the exposed regions 63a and 63c and the coating regions 63b and 63d are irradiated with laser light.

  As shown in FIG. 21, in the exposed regions 63a and 63c, the first cutting lines 63e and 63h along the outer peripheries of the tabs 66b and 67b and the second cutting lines along the edges of the main body portions 66a and 67a having the tabs 66b and 67b. Laser light is irradiated along the third cutting line 63k along the edge of the main body 66a opposite to the second cutting line 63f and 63f, 63i. As a result, the exposed regions 63a and 63c are cut at the first cutting lines 63e and 63h and the second cutting lines 63f and 63i. In the coating regions 63b and 63d, laser light is irradiated along the side edges of the main body portions 66a and 67a of the electrode sheets 66 and 67 to form cuts 63g and 63j. Then, a force is applied to the mother sheet 63 using the dividing device 34 shown in FIG. 10 to cut the mother sheet 63 at the cuts 63g and 63j. Thereby, the electrode sheets 66 and 67 can be divided from the mother sheet 63.

  As shown in FIG. 22, the mother sheet 64 has a row of coating regions 64b extending in the longitudinal direction and exposed regions 64a and 64c located on both sides in the width direction of the coating region 64b. The width of the coating region 64b is wide enough to form two electrode sheets 68 and 69 in the width direction. The electrode sheet 68 has a rectangular main body 68a formed from the coating region 64b, and a tab 68b that protrudes from the edge of the main body 68a and is formed from the exposed region 64a. The electrode sheet 69 has a rectangular main body 69a formed from the coating region 64b and a tab 69b formed from the exposed region 64c protruding from the edge of the main body 69a. When the mother sheet 64 is laser processed by the laser processing machine 35 shown in FIG. 5 or the like, both the exposed regions 64a and 64c and the coating region 64b are irradiated with laser light.

  As shown in FIG. 22, in the exposed regions 64a and 64c, the first cutting lines 64d and 64f along the outer peripheries of the tabs 68b and 69b and the second cutting lines along the edges of the main body portions 68a and 69a having the tabs 68b and 69b. Laser light is irradiated along 64e and 64g. As a result, the exposed regions 64a and 64c are cut at the first cutting lines 64d and 64f and the second cutting lines 64e and 64g. In the coating region 64b, the laser beam is irradiated so as to extend between the main body portions 68a and 69a of the electrode sheets 68 and 69, and a first cut 64i extending in the longitudinal direction is formed. Further, in the coating region 64b, laser light is irradiated along the space between the main body portions 68a of the electrode sheets 68 aligned in the longitudinal direction and between the main body portions 69a of the electrode sheets 69 aligned in the longitudinal direction, and the second extending in the width direction. A cut 64h is formed.

  The mother sheet 64 receives a force using the dividing device 34 and the like of FIG. 10 and breaks at the second cut 64h. Thus, the counter sheet including the electrode sheets 68 and 69 connected to each other is divided from the mother sheet 64. The counter sheet receives a force using the second dividing device 40 shown in FIG. 12 and the like, and breaks the counter sheet at the first notch 64i. Thus, the electrode sheets 68 and 69 are divided from the counter sheet.

  The separator 14 shown in FIG. 1 has substantially the same rectangular shape as the main body 12 a of the negative electrode sheet 12 or the main body 13 a of the positive electrode sheet 13. Instead of this, the separator may have a bag shape surrounding the positive electrode sheet 13. Or a separator is strip | belt shape and is folded in zigzag shape by the predetermined space | interval in a longitudinal direction. And the negative electrode sheet | seat 12 and the positive electrode sheet | seat 13 may be inserted alternately between the layers of the several separator formed by folding.

  As shown in FIGS. 11 and 15, the negative electrode sheets (electrode sheets 8 and 9) are stacked with the intermediate plate 43 therebetween. A positive electrode sheet (electrode sheets 8 and 9) and a separator are inserted separately into the gap between the electrode sheets 8 and 9 formed by the intermediate plate 43. Instead of this, the positive electrode sheet may be inserted into a bag-shaped separator in advance, and the positive electrode sheet and the separator may be inserted as a unit between the negative electrode sheet.

  As shown in FIG. 5, the laser beam is applied to the mother sheet 1 along the entire circumference of the electrode sheets 8 and 9. Alternatively, the laser beam may be irradiated at least at a part of the outer periphery of the electrode sheets 8 and 9, for example, at a predetermined interval. In this case, an unirradiated portion is formed on the outer periphery of the electrode sheets 8 and 9. Cutting lines or notches are located on both sides of the unirradiated part. Therefore, when the mother sheet 1 receives a force, the unirradiated portion can receive a relatively large force as compared with other portions. Accordingly, the unirradiated portion can be broken by the mechanical force applied to divide the notch 6. As a result, the counter sheet 7 can be separated from the mother sheet 1 or the electrode sheets 8 and 9 can be separated from the counter sheet 7.

  As shown in FIG. 12, the counter sheet 7 may be broken at the first notch 6 a by pressing the intermediate plate 43 against the corresponding region of the notch 6 a and using the intermediate plate 43. Instead of this, the counter sheet 7 may be broken at the first cut 6a without pressing the intermediate plate 43 against the corresponding region of the cut 6a, that is, without using the intermediate plate 43.

  As shown in FIGS. 12 and 13, both ends of the counter sheet 7 are lifted by bars 42, the counter sheet 7 is divided into electrode sheets 8 and 9, and the electrode sheets 8 and 9 are erected. That is, the electrode sheets 8 and 9 are rotated by approximately 90 degrees. Instead, one end of the counter sheet 7 may be lifted by the bar 42, the counter sheet 7 may be divided into electrode sheets 8 and 9, and the electrode sheet 9 may be stacked on the electrode sheet 8. That is, one of the electrode sheets 8 and 9 may be rotated 180 degrees with respect to the other, and the electrode sheets 8 and 9 may be stacked in the thickness direction in a collapsed state. In this case, the electrode sheets 8 and 9 may be lifted separately or integrally and moved onto the other electrode sheets 8 and 9, and the collapsed electrode sheets 8 and 9 may be stacked in the thickness direction.

  As shown in FIG. 7, the mother sheet 1 has active material layers 3 and 4 on both surfaces of the metal foil 2. Instead of this, the mother sheet 1 may have the active material layers 3 and 4 only on one side of the metal foil 2.

  The electrode sheets 8 and 9 described above are used as parts of a lithium ion battery that is one of the power storage devices. Alternatively, the electrode sheets 8 and 9 may be used as other power storage devices, for example, other secondary batteries, primary batteries, or capacitors.

1, 62, 63, 64 Base sheets 1a, 1b, 1c, 62a, 63a, 63c, 64a, 64c Exposed areas 1d, 1e, 62b, 63b, 63d, 64b Coating area 2 Metal foil 3, 4 Active material layer 5 , 65, 66, 67 Electrode sheets 5a, 5b, 5c, 5d, 62c, 62d, 63e, 63f, 63h, 63i, 64d, 64e, 64g Cutting line 6, 6a, 6b, 6c, 6d, 62e, 63g, 63j 64h, 64i Cut 7 Pair sheet 8, 9, 68, 69 Electrode sheet 8b, 9b, 12b, 13b, 65b, 66b, 67b, 68b, 69b Tab 8a, 9a, 12a, 13a, 65a, 66a, 67a, 68a, 69a Main body 10 Lithium ion battery 11 Electrode assembly 12 Negative electrode sheet 13 Positive electrode sheet 14 Separator 15 Case 16 Case main body 1 Lid 18 Negative electrode terminal 19 Positive electrode terminal 20 Coating / drying device 21 Supply machine 22 Coating machine 22a, 22b Slit die 23 Drying machine 24 Press machine 25 Tension applying machine 26 Winding machine 28 Collection box 29 Assist gas supply devices 30, 32, 33 Conveying device 34, 40, 60, 61, 70 Dividing device 35, 71 Laser processing machine 37 Scanner 38, 74 Laser oscillator 39, 75 Controller 41 Table 42 Bar 43 Intermediate plate 44 Stopper 50 Stocker 52 Housing part 53 Moving device 76 Assist gas supply device

Claims (9)

A method for producing an electrode sheet in which an active material layer containing an active material is formed on at least one region of a metal foil,
Preparing a strip-shaped mother sheet having a coating region where the active material layer is formed on a strip-shaped metal foil and an exposed region where the metal foil is exposed;
Irradiating the mother sheet with laser light along the shape of the electrode sheet, cutting the exposed region with the laser light, and forming a cut not penetrating in the coating region in the thickness direction with the laser light,
The manufacturing method of the electrode sheet which fractures | ruptures the said mother sheet | seat and divides | segments the said electrode sheet | seat from the said mother sheet | seat in the part in which the said mechanical sheet was mechanically applied and the said notch was formed. It is a manufacturing method of the electrode sheet according to claim 1,
The mother sheet has a first exposed region adjacent to the first end of the coating region, and a second exposed region adjacent to the second end of the coating region opposite to the first end,
The first electrode sheet including the first tab formed from the first exposed region and the second electrode sheet including the second tab formed from the second exposed region are adjacent to each other. The mother sheet is irradiated with laser light along the shape of the second electrode sheet, and the first electrode sheet and the second electrode sheet each have a main body portion in the coating region, and the first electrode sheet and the first electrode sheet A first notch along the boundary of the main body portion of the two-electrode sheet, and a first shape along the shape of the main body portion of the first electrode sheet and the second electrode sheet at a location different from the first notch in the coating region. Forming two cuts,
Applying mechanical force to the mother sheet to break the mother sheet at the second cut, and the counter sheet including the first electrode sheet and the second electrode sheet connected by the first cut to the mother sheet Split from the sheet,
Conveying the counter sheet,
A method for producing an electrode sheet, wherein mechanical force is applied to the counter sheet to break the counter sheet at the first cut and divide the counter sheet into the first electrode sheet and the second electrode sheet. It is a manufacturing method of the electrode sheet according to claim 2,
Forming the first tab and the second tab to be symmetrical with respect to the first cut;
The counter sheet is bent at the first cut so that the first tab and the second tab face each other, the counter sheet is broken at the first cut, and the counter sheet is formed with the first electrode sheet. A method for producing an electrode sheet that is divided into the second electrode sheets, and wherein the first tab and the second tab face each other and the first electrode sheet and the second electrode sheet face each other. It is a manufacturing method of the electrode sheet according to claim 3,
Lifting both sides of the counter sheet that is symmetric with respect to the first cut and breaking the counter sheet at the first cut to divide the counter sheet into the first electrode sheet and the second electrode sheet However, the manufacturing method of the electrode sheet which raises the said 1st electrode sheet and the said 2nd electrode sheet by making the edge corresponding to a said 1st notch into a lower side. It is a manufacturing method of the electrode sheet according to claim 4,
Push the upright first electrode sheet and the second electrode sheet in the thickness direction to move from the first position to the second position and stand on the stopper,
Similarly, the second pair sheet is moved to the first position to lift both sides of the second pair sheet, the second pair sheet is broken at the first notch, divided into two electrode sheets and raised. Then, the electrode sheet is moved to the second position, and the electrode sheet of the second pair sheet is overlaid on the electrode sheet previously moved to the second position. It is a manufacturing method of the electrode sheet according to any one of claims 3 to 5,
Set the intermediate plate at a position corresponding to the first cut,
By bending the counter sheet at the first cut, the intermediate plate is positioned between the first electrode sheet and the second electrode sheet,
A method for producing an electrode sheet, wherein a third electrode sheet is inserted between the first electrode sheet and the second electrode sheet while removing the intermediate plate from between the first electrode sheet and the second electrode sheet. An electrode sheet manufacturing apparatus for manufacturing an electrode sheet in which an active material layer containing an active material is formed on at least one region of a metal foil,
A transport device for transporting a belt-shaped mother sheet having a coating region where the active material layer is formed on a strip-shaped metal foil and an exposed region where the metal foil is exposed;
A laser beam is irradiated along the shape of the electrode sheet on the mother sheet on the conveying device, the exposed region is cut by the laser beam, and the laser beam does not penetrate the coating region in the thickness direction. A laser processing machine to form
An apparatus for manufacturing an electrode sheet, comprising: a dividing device that breaks the mother sheet and divides the electrode sheet from the mother sheet at a portion where the cut is formed by mechanically applying force to the mother sheet. The electrode sheet manufacturing apparatus according to claim 7,
The dividing device includes a second conveying device positioned downstream of the conveying device and below the conveying device, and when the leading edge of the mother sheet falls from the conveying device to the second conveying device. An apparatus for manufacturing an electrode sheet that mechanically applies force to the mother sheet by using gravity. The electrode sheet manufacturing apparatus according to claim 7 or 8,
The dividing device has a second conveying device that is located downstream of the conveying device and has a conveying speed faster than the conveying device, and when the leading edge of the mother sheet reaches the second conveying device from the conveying device The manufacturing apparatus for electrode sheets which mechanically applies force to the mother sheet by the second conveying device pulling the tip of the mother sheet.

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