WO2013054593A1 - Sheet-shaped electrode fabrication method, sheet-shaped electrode, and lithium-ion secondary battery - Google Patents

Abstract

The purpose of the invention is to fabricate a sheet-shaped electrode (1) by cutting an elongated electrode substrate (30) having an electrode mixture layer (35) intermittently formed on at least one surface of a collector, the sheet-shaped electrode comprising a substantially rectangular electrode portion (20) on which the electrode mixture layer is formed and a tab portion (27) including a region in which the electrode mixture layer is not formed. A method for fabricating the sheet-shaped electrode includes: a step of forming the tab portion of the sheet-shaped electrode and a first side (21) from which the tab portion projects by using a first cutting blade (41) having a cuttable width (W41) wider than the width of the electrode substrate; and a step of forming a second side (22) facing the first side of the sheet-shaped electrode by using a second cutting blade (42) having a cuttable width (W42) wider than the width of the electrode substrate. This makes it possible to efficiently fabricate sheet-shaped electrodes having different sizes at low cost by using the same cutting blades.

Description

Sheet electrode manufacturing method, sheet electrode, and lithium ion secondary battery

The present invention relates to a method for manufacturing a sheet-like electrode. Moreover, this invention relates to the lithium ion secondary battery provided with the sheet-like electrode manufactured using the said manufacturing method, and the said sheet-like electrode.

Non-aqueous electrolyte batteries represented by lithium ion secondary batteries are widely used as power sources for portable devices such as mobile phones and notebook personal computers because of their high energy density. With higher performance of portable devices, further increase in capacity of lithium ion secondary batteries is being promoted. In order to further improve the energy density, a laminated lithium ion sheathed with a flexible laminate sheet in which a metal foil such as an aluminum foil is used as a core material and a heat-fusible resin film is laminated as an adhesive layer on its inner surface Secondary batteries are often used.

As an electrode laminated body incorporated in a laminated lithium ion secondary battery, for example, a sheet-like positive electrode housed in a bag-like separator and a sheet-like negative electrode are alternately stacked (Patent Document 1). And a separator in which a separator is folded in a zigzag manner, and sheet-like positive electrodes and sheet-like negative electrodes are alternately stacked via separators (see Patent Document 2).

The sheet-like electrodes of the positive electrode and the negative electrode used in these electrode laminates are generally a rectangular electrode portion in which an electrode mixture layer containing an active material is applied to a metal foil as a current collector, and the rectangular shape. And a tab portion that protrudes from one side of the electrode portion and is not coated with an electrode mixture layer. In such a sheet-like electrode, an electrode base material in which an electrode mixture layer is intermittently applied to a strip-shaped current collector is punched at once with a die having a cutting blade shape that matches the shape of the desired sheet-like electrode. (See Patent Document 3).

JP 7-302616 A WO 06/120959 pamphlet JP 2002-231230 A

Generally, a laminate-type lithium ion secondary battery has an advantage that it is excellent in the degree of freedom of size change according to the shape of the device in which it is built. However, in order to change the size of the sheet-like electrode incorporated in the lithium ion secondary battery, a mold for punching the sheet-like electrode is prepared in advance for each size of the sheet-like electrode, and production is attempted. It is necessary to exchange the mold every time the size of the sheet electrode to be changed. This leads to an increase in cost due to creation and storage of various types of molds, and a reduction in work efficiency and productivity due to mold replacement. This problem becomes more serious as the number of types of sheet electrode sizes increases. Therefore, it is actually difficult to produce a variety of sheet-like electrodes.

The present invention solves the above-described conventional problems, and can use the same cutting blade to efficiently manufacture sheet-shaped electrodes having different sizes at low cost, and a universal sheet-shaped electrode manufacturing method. The purpose is to provide. Another object of the present invention is to provide an inexpensive sheet electrode and a lithium ion secondary battery.

In the method for producing a sheet-like electrode according to the present invention, a long electrode base material in which an electrode mixture layer containing an active material is intermittently formed on at least one surface of a belt-like current collector in the longitudinal direction of the current collector. A sheet-like shape having a substantially rectangular electrode portion that is cut and formed with the electrode mixture layer, and a tab portion that includes a region that protrudes from one side of the electrode portion and is not formed with the electrode mixture layer An electrode is manufactured. The manufacturing method includes the step of forming the tab portion of the sheet-like electrode and the first side from which the tab portion protrudes using a first cutting blade having a cuttable width longer than the width of the electrode base material. Forming a second side opposite to the first side of the sheet-like electrode using a second cutting blade having a cuttable width longer than the width of the electrode base material.

The sheet-like electrode of the present invention is produced using the above-described method for producing a sheet-like electrode.

The lithium ion secondary battery of the present invention includes the sheet-like electrode.

According to the present invention, the electrode substrate is cut using the first cutting blade and the second cutting blade having a cuttable width longer than the width of the electrode substrate. Accordingly, by appropriately changing the positions of the first cutting blade and the second cutting blade in the width direction and the longitudinal direction with respect to the electrode substrate, sheet-like electrodes having different sizes using the same first cutting blade and second cutting blade can be obtained. Can be manufactured. As a result, many types of sheet-like electrodes having different sizes can be efficiently manufactured at low cost.

Furthermore, according to the present invention, an inexpensive sheet electrode and a lithium ion secondary battery can be realized.

FIG. 1 is a plan view of a sheet-like electrode according to Embodiment 1 of the present invention. FIG. 2 is a plan view of an electrode base material for manufacturing the sheet electrode according to the first embodiment of the present invention. FIG. 3 is a plan view showing a cutting position by the first cutting blade and the second cutting blade with respect to the electrode base material in the sheet-like electrode manufacturing method according to Embodiment 1 of the present invention. FIG. 4A is a plan view of an electrode substrate piece obtained by cutting an electrode substrate with a first cutting blade and a second cutting blade in the method for manufacturing a sheet-like electrode according to Embodiment 1 of the present invention. FIG. 4B is an enlarged plan view of a first corner portion of the sheet-like electrode formed by the sheet-like electrode manufacturing method according to Embodiment 1 of the present invention. FIG. 5 is a plan view of a sheet-like electrode according to Embodiment 2 of the present invention. FIG. 6 is a plan view of a first electrode base material piece obtained by cutting an electrode base material with a first cutting blade and a second cutting blade in the sheet-like electrode manufacturing method according to Embodiment 2 of the present invention. is there. FIG. 7 is a plan view of a second electrode substrate piece obtained by cutting an electrode substrate with first to fourth cutting blades in the method for producing a sheet-like electrode according to Embodiment 2 of the present invention. FIG. 8 is a perspective plan view showing a schematic configuration of a lithium ion secondary battery according to Embodiment 3 of the present invention. FIG. 9 is a perspective view showing a configuration of an electrode laminate constituting the lithium ion secondary battery according to Embodiment 3 of the present invention. FIG. 10A is a perspective view showing a pancake of an electrode substrate for a negative electrode used in Examples 1 and 2 of the present invention. FIG. 10B is a plan view of a part of the electrode substrate for a negative electrode shown in FIG. 10A. FIG. 11 is a plan view of a first electrode substrate piece for negative electrode obtained by cutting an electrode substrate for negative electrode at a constant pitch with a first cutting blade for negative electrode in Examples 1 and 2 of the present invention. is there. FIG. 12 is a plan view of a second electrode substrate piece for negative electrode obtained by cutting a first electrode substrate piece for negative electrode with a second cutting blade in Examples 1 and 2 of the present invention. FIG. 13 is a plan view of a negative electrode sheet electrode obtained in Examples 1 and 2 of the present invention. 14A, 14B, and 14C are partially enlarged plan views of the portions 14A, 14B, and 14C of FIG. FIG. 15A is a perspective view showing a pancake of an electrode base material for a positive electrode used in Examples 1 and 2 of the present invention. FIG. 15B is a plan view of a part of the electrode substrate for a positive electrode shown in FIG. 15A. FIG. 16 is a plan view of the first electrode substrate piece for positive electrode obtained by cutting the electrode substrate for positive electrode at a constant pitch with the first cutting blade for positive electrode in Examples 1 and 2 of the present invention. is there. FIG. 17 is a plan view of a second electrode substrate piece for a positive electrode obtained by cutting a first electrode substrate piece for a positive electrode with a second cutting blade in Examples 1 and 2 of the present invention. FIG. 18 is a plan view of a positive electrode sheet electrode obtained in Examples 1 and 2 of the present invention. 19A, 19B, and 19C are partially enlarged plan views of the portions 19A, 19B, and 19C of FIG. FIG. 20A is a plan view showing the cutting blade shape of the first cutting blade for a negative electrode used in Examples 1 and 2 of the present invention. FIG. 20B is a plan view showing the cutting blade shape of the second cutting blade for negative electrode and positive electrode used in Examples 1 and 2 of the present invention. FIG. 20C is a plan view showing the cutting blade shape of the first cutting blade for positive electrode used in Examples 1 and 2 of the present invention. FIGS. 21A to 21D are plan views showing the cutting blade shapes of the corner cutting blades used in Examples 1 and 2 of the present invention. FIG. 22 is a plan view of the electrode laminate obtained in Examples 1 and 2 of the present invention.

In the method for producing a sheet-like electrode according to the present invention, a long electrode base material in which an electrode mixture layer containing an active material is intermittently formed on at least one surface of a belt-like current collector in the longitudinal direction of the current collector. A sheet-like shape having a substantially rectangular electrode portion that is cut and formed with the electrode mixture layer, and a tab portion that includes a region that protrudes from one side of the electrode portion and is not formed with the electrode mixture layer An electrode is manufactured. The manufacturing method includes the step of forming the tab portion of the sheet-like electrode and the first side from which the tab portion protrudes using a first cutting blade having a cuttable width longer than the width of the electrode base material. Forming a second side opposite to the first side of the sheet-like electrode using a second cutting blade having a cuttable width longer than the width of the electrode base material.

It is preferable that the manufacturing method of the present invention further includes a step of adjusting the positions of the first cutting blade in the longitudinal direction and the width direction of the electrode base material. Thereby, the sheet-like electrode from which the width | variety of a tab part and the length of a sheet-like electrode can differ can be manufactured using the same 1st cutting blade.

The manufacturing method of the present invention may further include a step of adjusting the position of the second cutting blade in the longitudinal direction of the electrode base material. Thereby, the sheet-like electrode from which length differs can be manufactured using the same 2nd cutting blade.

The width of the electrode substrate is preferably the same as the width of the sheet-like electrode. Thereby, since the process of cutting the side of the electrode base material so as to match the desired width of the sheet-like electrode is not required, the manufacturing process of the sheet-like electrode can be simplified.

In the manufacturing method of the present invention, at least one of the four corners of the sheet-like electrode is formed in an arc shape using an arc-shaped corner cutting blade different from the first cutting blade and the second cutting blade. It is preferable to further include a step. Thereby, at least one of the four corners of the sheet-like electrode can be formed in an arc shape. Furthermore, even if the size of the sheet-like electrode is different, each of the four corners can be formed in an arc shape by using the same corner cutting blade.

It is preferable that the central angle of the arc formed at at least one of the four corners of the sheet-like electrode is less than 90 °. Thereby, the positioning accuracy of the corner cutting blade can be relaxed.

The arc length of the corner cutting blade is preferably longer than the arc length of the arc formed at the corner of the sheet-like electrode by the corner cutting blade. Thereby, the positioning accuracy of the corner cutting blade can be relaxed.

It is preferable that the sheet electrode is a negative electrode sheet electrode. In general, the negative electrode sheet electrode is larger than the positive electrode sheet electrode. Therefore, by forming at least one of the four corners of the negative electrode sheet electrode in an arc shape, the handleability of the electrode laminate in which the negative electrode sheet electrode and the positive electrode sheet electrode are stacked via the separator is remarkable. To improve.

It is preferable that the manufacturing method of the present invention further includes a step of adjusting the position of the corner cutting blade in the first side direction and the direction orthogonal thereto. Thereby, each of the four corners of the sheet-like electrode having different four corner positions (that is, different sizes) can be formed in an arc shape using the same corner cutting blade.

In the manufacturing method of the present invention, at least one of the pair of side edges excluding the first side and the second side of the sheet-like electrode is separated from the first cutting blade and the second cutting blade. It is preferable to further include a step of forming using three cutting blades. Thereby, the sheet-like electrode from which a width | variety differs can be easily manufactured from the same electrode base material.

It is preferable that a cuttable width of the third cutting blade is longer than the length of at least one of the pair of side edges. Thereby, the sheet-like electrode from which length differs can be manufactured using the same 3rd cutting blade.

It is preferable that the manufacturing method of the present invention further includes a step of adjusting the position of the third cutting blade in the first side direction. Thereby, the sheet-like electrode from which width differs can be manufactured using the same 3rd cutting blade.

One of the pair of side edges is formed using the third cutting blade, and the other is a fourth cutting blade different from the first cutting blade, the second cutting blade, and the third cutting blade. It is preferable to use and cut. This further increases the number of types of sheet-like electrodes that can be manufactured from the same electrode substrate.

Hereinafter, the present invention will be described in detail while showing preferred embodiments. However, it goes without saying that the present invention is not limited to the following embodiments. For convenience of explanation, the drawings referred to in the following description show only the main members necessary for explaining the present invention in a simplified manner among the constituent members of the embodiment of the present invention. Therefore, the present invention can include arbitrary components not shown in the following drawings. In addition, the dimensions of the members in the following drawings do not faithfully represent the actual dimensions of the constituent members and the dimensional ratios of the members.

(Embodiment 1)
FIG. 1 is a plan view of a sheet-like electrode 1 according to Embodiment 1 of the present invention. The sheet-like electrode 1 includes a substantially rectangular electrode part 20 in which an electrode mixture layer containing an active material is formed on one or both sides of a current collector made of metal foil or the like, and a tab protruding from one side of the electrode part 20 Part 27. The electrode mixture layer is not formed on the entire tab part 27 or at least a part of the front end side (the side opposite to the electrode part 20), and the current collector is exposed. In FIG. 1, a large number of dots are attached to the region where the electrode mixture layer is formed.

The sheet electrode 1 can be used for both the positive electrode and the negative electrode. However, according to the polarity of the sheet-like electrode 1, the position of the tab part 27, the dimension of the sheet-like electrode 1, the material of a collector or an electrode mixture layer, etc. are changed suitably.

For convenience of the following description, of the four sides surrounding the substantially rectangular electrode portion 20, the side on which the tab portion 27 is formed is the first side 21, the side facing the first side 21 is the second side 22, Two opposite sides other than the first side 21 and the second side 22 are referred to as a first side 23 and a second side 24. In this example, the tab portion 27 is formed along the second side 24. The first side 21 and the second side 22 are parallel to each other, and the first side 23 and the second side 24 are parallel to each other. The first side 21 and the second side 22 are orthogonal to the first side 23 and the second side 24. Of the two ends of the first side 23, the corner at the end on the first side 21 side is the first corner 25 a, the corner at the end on the second side 22 is the second corner 25 b, and the second side 24. Of these two ends, the corner at the end on the second side 22 side is called the third corner portion 25c, and the corner at the end on the first side 21 side is called the fourth corner portion 25d. In the example of FIG. 1, the fourth corner portion 25 d is located on the tab portion 27. The edges of the first to fourth corner portions 25a to 25d are formed in an arc shape.

In FIG. 1, the tab portion 27 is formed along the second side 24 at the end on the second side 24 side of the first side 21, but on the first side at the end on the first side 23 side. It may be formed along the side 23, or may be formed at a position on the first side 21 away from both the first side 23 and the second side 24. In FIG. 1, the tab portion 27 is formed on the short side of the substantially shaped electrode portion 20, but may be formed on the long side.

The direction in which the first side edge 23 and the second side edge 24 face each other (the left-right direction in FIG. 1) is referred to as the “width direction”, and the direction in which the first edge 21 and the second edge 22 face each other (up and down in FIG. Direction) is called “longitudinal direction”. The “longitudinal direction” of the sheet-like electrode 1 is a convenient name for the “width direction”, and the “longitudinal direction” of the sheet-like electrode 1 does not mean the “major axis direction” of the sheet-like electrode 1. Absent.

Next, a method for manufacturing the sheet-like electrode 1 shown in FIG. 1 will be described.

First, a long electrode substrate 30 as shown in FIG. 2 is prepared. The electrode substrate 30 includes a strip-shaped current collector extending in the vertical direction of the paper surface of FIG. In FIG. 2, the area | region which attached | subjected the dot is the electrode area | region 35 which formed the electrode mixture layer containing an active material in the single side | surface or both surfaces of the collector as a base material. The area | region which has not attached | subjected the dot is the non-electrode area | region 37 where the electrode mixture layer was not formed but the electrical power collector was exposed. The electrode regions 35 and the non-electrode regions 37 are regularly and alternately arranged at a constant pitch in the longitudinal direction of the current collector (up and down direction on the paper surface of FIG. 2). When the electrode regions 35 are formed on both surfaces of the current collector, the positions of the electrode region 35 and the non-electrode region 37 are the same on both surfaces. The width W30 of the electrode base material 30 (the dimension in the left-right direction of the electrode base material 30 in FIG. 2) is the same as the width W1 (see FIG. 1) of the sheet-like electrode 1 to be manufactured. There is no restriction | limiting in particular in the preparation methods of the electrode base material 30. FIG. For example, the material of the electrode mixture layer can be transferred and formed on the surface of a traveling belt-like current collector using a printing roll.

Next, as shown in FIG. 3, the electrode base material 30 is cut along the broken lines 41 and 42 so as to cross the width direction.

The broken line 41 indicates the first cutting blade (more precisely, the cutting blade shape of the first cutting blade). The first cutting blade 41 has the same stepped shape as the outline of the tab portion 27 of the sheet-like electrode 1 shown in FIG. 1 and the first side 21 from which the tab portion 27 protrudes. As can be easily understood from FIG. 3, the dimension of the first cutting blade 41 in the width direction of the electrode base material 30 (that is, the cuttable width of the first cutting blade 41) W41 is larger than the width W30 of the electrode base material 30. Big enough.

The broken line 42 indicates a second cutting blade independent of the first cutting blade (more precisely, the cutting blade shape of the second cutting blade). The second cutting blade 42 has a linear shape parallel to the width direction of the electrode substrate 30. As can be easily understood from FIG. 3, the dimension of the second cutting blade 42 in the width direction of the electrode base material 30 (that is, the severable width of the second cutting blade 42) W42 is larger than the width W30 of the electrode base material 30. Big enough.

For example, the electrode substrate 30 is first cut using the first cutting blade 41 while intermittently unwinding the long electrode substrate 30 wound on a roll. Next, the electrode substrate 30 is cut using the second cutting blade 42. On the contrary, after cutting using the second cutting blade 42, the first cutting blade 41 may be used for cutting. Or you may cut | disconnect using the 1st cutting blade 41 and the 2nd cutting blade 42 simultaneously.

1st cutting blade 41 and 2nd cutting blade 42 can be attached to the member (henceforth "elevating member") which raises / lowers a punching apparatus, for example. The 1st cutting blade 41 and the 2nd cutting blade 42 may be attached to the same raising / lowering member, and may be attached to two different raising / lowering members, respectively. The cutting positions of the first cutting blade 41 and the second cutting blade 42 can be changed by changing the mounting positions of the first cutting blade 41 and the second cutting blade 42 with respect to the lifting member.

The positions of the first cutting blade 41 in the width direction (left and right direction in FIG. 3) and the longitudinal direction (up and down direction in FIG. 3) with respect to the electrode substrate 30 are set according to the size of the sheet-like electrode 1 to be formed. Is done. For example, the position of the first cutting blade 41 in the width direction can be set in consideration of the width W27 (see FIG. 1) of the tab portion 27 to be formed. The cutting position in the longitudinal direction of the first cutting blade 41 can be set in consideration of the relationship between the boundary position between the electrode region 35 and the non-electrode region 37 and the tab portion 27 to be formed.

The position of the second cutting blade 42 in the longitudinal direction (vertical direction in FIG. 3) with respect to the electrode substrate 30 is set according to the size of the sheet electrode 1 to be formed. Specifically, the length of the second cutting blade 42 is set such that the cutting position of the first cutting blade 41 and the cutting position of the second cutting blade 42 coincide with the longitudinal dimension of the sheet-like electrode 1 to be formed. The cutting position in the direction can be set.

FIG. 4A is a plan view of the electrode substrate piece 31 obtained by cutting the long electrode substrate 30 with the first cutting blade 41 and the second cutting blade 42 shown in FIG. As shown in FIG. 4A, the four corners of the electrode base piece 31 are cut off along broken lines 46a, 46b, 46c, and 46d. Broken lines 46a, 46b, 46c and 46d indicate the first to fourth corner cutting blades (more precisely, the cutting blade shapes of the first to fourth corner cutting blades) in order. The first corner cutting blade 46a, the second corner cutting blade 46b, the third corner cutting blade 46c, and the fourth corner cutting blade 46d are independent from each other.

The first to fourth corner cutting blades 46a to 46d have arc shapes having the same curvature as the arcs formed in the first to fourth corner portions 25a to 25d shown in FIG. As can be easily understood from FIG. 4A, the arc lengths of the arcs of the first to fourth corner cutting blades 46a to 46d (that is, the cutable lengths of the first to fourth corner cutting blades 46a to 46d) are as shown in FIG. It is sufficiently longer than the arc length of the arc formed in the first to fourth corner portions 25a to 25d shown in FIG. The central angle of the arcs of the first to fourth corner cutting blades 46a to 46d is preferably as large as possible within a range of 90 ° or less.

The order of cutting using the first to fourth corner cutting blades 46a to 46d is arbitrary. These four cutting blades 46a to 46d may be cut using one by one in order, or two or more (of course, all four) may be used simultaneously for cutting.

The first to fourth corner cutting blades 46a to 46d can be attached to elevating members of a punching device, for example. The first to fourth corner cutting blades 46a to 46d may be attached to the same elevating member, or may be separately attached to two or more different elevating members. By changing the mounting positions of the first to fourth corner cutting blades 46a to 46d with respect to the elevating member, the cutting positions by the first to fourth corner cutting blades 46a to 46d can be changed. Specifically, the positions of the first to fourth corner cutting blades 46a to 46d in the width direction (left and right direction in FIG. 3) and the longitudinal direction (up and down direction in FIG. 3) are the sheet-like electrodes to be formed. 1 can be set according to the size of 1 (that is, the positions of the first to fourth corners 25a to 25d).

Thus, the sheet electrode 1 shown in FIG. 1 is obtained.

As described above, in the manufacturing method of the sheet-like electrode 1 according to the first embodiment, the first cutting blade 41 and the second cutting blade 42 having a cuttable width longer than the width W30 of the long electrode substrate 30 are used. Then, the electrode base material 30 is cut so as to cross the width direction, and the tab portion 27, the first side 21, and the second side 22 are formed. Therefore, even when the width W30 of the electrode base material 30, that is, the width W1 of the sheet-like electrode 1 to be finally obtained is changed, the width W30 (or the width W1) is cut by the first cutting blade 41. If it is not larger than the possible width W41 and the cuttable width W42 of the second cutting blade 42, it is not necessary to replace the first cutting blade 41 and the second cutting blade 42, and the same first cutting blade 41 and second cutting blade 42 are used. Can be used to cut.

When the width W27 (see FIG. 1) of the tab portion 27 of the sheet-like electrode 1 is changed, the relative position in the width direction of the first cutting blade 41 with respect to the electrode base material 30 may be changed. Moreover, when changing the length L20 (refer FIG. 1) of the electrode part 20 of the sheet-like electrode 1, relative to the longitudinal direction of the 1st cutting blade 41 and / or the 2nd cutting blade 42 with respect to the electrode base material 30. FIG. What is necessary is just to change a position.

End edges of the first to fourth corner portions 25a to 25d are formed in an arc shape by using first to fourth corner cutting blades 46a to 46d that are independent from the first cutting blade 41 and the second cutting blade 42. . Therefore, even if the relative position of the first cutting blade 41 and / or the second cutting blade 42 with respect to the electrode base material 30 is changed in accordance with the size change of the sheet-like electrode 1 to be manufactured, the first to second It is not necessary to replace the four corner cutting blades 46a to 46d, and the relative positions of the first to fourth corner cutting blades 46a to 46d with respect to the electrode base piece 31 may be changed.

FIG. 4B is an enlarged plan view of the first corner 25a of the sheet-like electrode 1 obtained by the manufacturing method of the first embodiment. An arc 26 is formed in the first corner 25a using only a part of the first corner cutting blade 46a. Therefore, the central angle θ of the circular arc 26 defined by both ends 26a and 26b of the circular arc 26 and the center 26c of the circular arc 26 is generally less than 90 °. In addition, the tangent lines 27 a and 27 b of the arc 26 at both ends 26 a and 26 b of the arc 26 generally do not coincide with the first side 21 and the first side 23. By forming such an arc 26 in the first corner 25a using the first corner cutting blade 46a, the relative positioning accuracy of the first corner cutting blade 46a with respect to the electrode substrate piece 31 can be relaxed. . In FIG. 4B, the first corner 25a has been described, but the same applies to the second to fourth corners 25b to 25d.

Therefore, according to the first embodiment, the sheet-like electrodes 1 having different sizes can be obtained without replacing the first cutting blade 41, the second cutting blade 42, and the first to fourth corner cutting blades 46a to 46d. Manufacture can be performed simply by changing the cutting position. Therefore, many types of sheet-like electrodes 1 having different sizes can be manufactured efficiently and at low cost.

In the above-described manufacturing method, the first and fourth corner cutting blades 46a to 46d are cut after the first and second cutting blades 41 and 42, but the order of these cuttings is not limited to this. For example, after the first cutting blade 41 is cut, the first and fourth corner cutting blades 46a and 46d are cut, and after the second cutting blade 42 is cut, the second and third corner cutting blades 46b and 46c are cut. You may go. Alternatively, the cutting with the first to fourth corner cutting blades 46a to 46d may be performed before the cutting with the first cutting blade 41 and the second cutting blade 42.

Also, some or all of the cutting by the first to fourth corner cutting blades 46a to 46d can be omitted. One of the reasons for forming the first to fourth corner portions 25a to 25d in an arc shape is that the corner portion of the sheet-like electrode 1 is caught by other members in the manufacturing process of the lithium ion secondary battery, so that the yield and The purpose is to prevent the productivity from decreasing. In general, the positive electrode sheet electrode is smaller than the negative electrode sheet electrode. Therefore, the possibility that the corner of the sheet electrode is caught by another member is higher in the negative electrode sheet than in the positive electrode sheet. Therefore, the cutting by the first to fourth corner cutting blades 46a to 46d can be omitted for the positive electrode sheet-like electrode and performed only for the negative electrode sheet-like electrode. Thereby, the manufacturing man-hour of the sheet-like electrode for positive electrodes can be decreased. Alternatively, as in Examples 1 and 2 to be described later, it is possible to omit forming the fourth corner portion 25d on the tab portion 27 in an arc shape.

The configurations of the first cutting blade 41, the second cutting blade 42, and the first to fourth corner cutting blades 46a to 46d are arbitrary. For example, a shearing blade (such as a punching blade or scissors) that cuts the object to be cut between the two objects by sandwiching the object to be cut (electrode base material 30 and electrode base material piece 31). It may be a Thomson blade or a similar one that cuts by pressing a blade arranged on one side of the workpiece against the workpiece, or any other than these A cutting blade may be used.

The relative positioning of the object to be cut (the electrode base material 30, the electrode base material piece 31) and the cutting blade may move only one of the object to be cut and the cutting blade, or may move both. Good.

(Embodiment 2)
In Embodiment 1, the sheet-like electrode 1 having the same width as this was manufactured using the electrode base material 30 having the width W30 (see FIG. 2). On the other hand, in this Embodiment 2, the sheet-like electrode 2 narrower than the electrode base material 30 is manufactured.

In the following description, the same elements as those shown in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Hereinafter, the second embodiment will be described with a focus on differences from the first embodiment.

FIG. 5 is a plan view of the sheet-like electrode 2 according to the second embodiment of the present invention. This sheet-like electrode 2 differs from the sheet-like electrode 1 of the first embodiment in that it has a width W2 that is narrower than the width W1 of the sheet-like electrode 1 of the first embodiment. Except for this, the sheet electrode 2 of the second embodiment is the same as the sheet electrode 1 of the first embodiment.

A method for manufacturing the sheet-like electrode 5 shown in FIG. 5 will be described.

First, similarly to the first embodiment, a long electrode substrate 30 shown in FIG. 2 is prepared. The width W30 of the electrode substrate 30 is larger than the width W2 (see FIG. 5) of the sheet-like electrode 2 to be manufactured.

Next, similarly to the first embodiment, the electrode substrate 30 is cut across the width direction using the first cutting blade 41 and the second cutting blade 42 (see FIG. 3), and the first shown in FIG. The electrode substrate piece 31a is obtained.

The both sides of the first electrode base piece 31a are cut off along the broken lines 43 and 44 as shown in FIG.

The broken line 43 indicates the third cutting blade (more precisely, the cutting blade shape of the third cutting blade), and the broken line 44 indicates the fourth cutting blade (more precisely, the cutting blade shape of the fourth cutting blade). Show. The third cutting blade 43 and the fourth cutting blade 44 are independent from each other. The 3rd cutting blade 43 and the 4th cutting blade 44 are the longitudinal directions of the 1st electrode base-material piece 31a (namely, the up-down direction of the paper surface of FIG. 6. This is the longitudinal direction of the electrode base material 30 shown in FIG. And a straight line shape parallel to. As can be easily understood from FIG. 6, the dimension (cuttable width) W43 of the third cutting blade 43 in the longitudinal direction of the first electrode base piece 31a and the dimension (cuttable width) of the fourth cutting blade 44 in the same direction. W44 is sufficiently longer than the length L23 of the first side 23 and the length L24 (see FIG. 5) of the second side 24 of the sheet electrode 2 to be manufactured.

The 3rd cutting blade 43 and the 4th cutting blade 44 can be attached to the raising / lowering member of a punching apparatus, for example. The 3rd cutting blade 43 and the 4th cutting blade 44 may be attached to the same raising / lowering member, and may be attached to two different raising / lowering members, respectively. The cutting position by the third cutting blade 43 and the fourth cutting blade 44 can be changed by changing the attachment position of the third cutting blade 43 and the fourth cutting blade 44 to the lifting member.

The positions of the third cutting blade 43 and the fourth cutting blade 44 in the width direction (left and right direction in FIG. 6) with respect to the first electrode substrate piece 31a are set according to the size of the sheet electrode 1 to be formed. . For example, the cutting position in the width direction of the fourth cutting blade 44 can be set so that the tab portion 27 having a desired width W27 (see FIG. 5) can be obtained. In addition, the cutting position in the width direction of the third cutting blade 43 and the fourth cutting blade 44 is such that the interval between the cutting position of the third cutting blade 43 and the cutting position of the fourth cutting blade 44 is to be formed. It can be set to match the width W2 of 2.

The order of the cutting by the third cutting blade 43 and the cutting by the fourth cutting blade 44 is arbitrary. The cutting with the third cutting blade 43 and the cutting with the fourth cutting blade 44 can be performed simultaneously.

FIG. 7 is a plan view of the second electrode substrate piece 31b obtained by cutting the first electrode substrate piece 31a with the third cutting blade 43 and the fourth cutting blade 44 shown in FIG. The four corners of the second electrode base material piece 31b are the same as described in FIG. 4A of the first embodiment, and the first corner cutting blade 46a, the second corner cutting blade 46b, and the third corner shown by broken lines in FIG. Cut off with the cutting blade 46c and the fourth corner cutting blade 46d.

Thus, the sheet electrode 2 shown in FIG. 5 is obtained.

As described above, in the manufacturing method of the sheet-like electrode 2 according to the second embodiment, in addition to the manufacturing method of the sheet-like electrode 1 according to the first embodiment, the both sides of the first electrode base material piece 31a are connected to the third cutting blade 43. And a step of forming the first side edge 23 and the second side edge 24 by cutting off with the fourth cutting blade 44. Therefore, even if the width W2 of the sheet-like electrode 2 to be finally obtained is smaller than the width W30 of the electrode base piece 30, a cutting process by the third cutting blade 43 and the fourth cutting blade 44 is added. Except for the above, it is not necessary to replace the first and second cutting blades 41 and 42 and the first to fourth corner cutting blades 46a to 46d used in the first embodiment. It can be used as well.

When changing the width W2 of the sheet-like electrode 2, the cutting position in the width direction of the third cutting blade 43 and the fourth cutting blade 44 may be changed. Moreover, when changing the width W27 (refer FIG. 5, FIG. 6) of the tab part 27 of the sheet-like electrode 2, if the position of the width direction of the 1st cutting blade 41 and / or the 4th cutting blade 44 is changed. Good.

Even when the length L23 of the first side 23 and the length L24 of the second side 24 of the sheet-like electrode 2 to be finally obtained are changed, the length L23 of the first side 23 is If it is not larger than the cuttable width W43 of the third cutting blade 43, it is not necessary to replace the third cutting blade 43, and the length L24 of the second side 24 is larger than the cuttable width W44 of the fourth cutting blade 44. Otherwise, it is not necessary to replace the fourth cutting blade 44. Accordingly, the same third cutting blade 43 and fourth cutting blade 44 can be used for cutting.

Other than the above, as described in the first embodiment, the cutting positions of the first cutting blade 41, the second cutting blade 42, and the first to fourth corner cutting blades 46a to 46d are changed according to the size of the sheet-like electrode 2. do it.

Therefore, according to the second embodiment, the sheet-like electrodes 2 having different sizes can be cut without replacing the first to fourth cutting blades 41 to 44 and the first to fourth corner cutting blades 46a to 46d. It can be manufactured simply by changing the position. Therefore, many types of sheet-like electrodes 2 having different sizes can be efficiently manufactured at low cost.

Further, unlike Embodiment 1, in Embodiment 2, since the electrode substrate 30 wider than the width W2 of the sheet electrode 2 can be used to manufacture the sheet electrode 2, the width of the sheet electrode can be used. There is no need to manufacture the electrode substrate 30 according to the above. This is also advantageous for efficient and low-cost production of various types of sheet-like electrodes having different sizes.

In the above-described manufacturing method, the third cutting blade 43 and the fourth cutting blade 44 that are independent from each other are used, but either one of the cutting blades may be omitted. That is, even when only the third cutting blade 43 (or the fourth cutting blade 44) is used and moved in the width direction, both the first and second side edges 23 and 24 of the sheet-like electrode 2 are formed. Good.

Moreover, in the manufacturing method mentioned above, in order to obtain the sheet-like electrode 2 having the width W2, the cutting with the third cutting blade 43 and the cutting with the fourth cutting blade 44 were performed. Cutting can be omitted. That is, one of the both sides in the width direction of the long electrode substrate 30 shown in FIG. 2 can be set as one of the first and second sides 23 and 24 of the sheet-like electrode 2. . Thereby, the manufacturing process of the sheet-like electrode 2 can be simplified.

In the manufacturing method described above, cutting with the first and second cutting blades 41 and 42, cutting with the third and fourth cutting blades 43 and 44, and cutting with the first to fourth corner cutting blades 46a to 46d were performed in this order. However, the order of these cuts is not limited to this. For example, after cutting with the third and fourth cutting blades 43 and 44, the cutting with the first and second cutting blades 41 and 42 may be performed. Alternatively, the cutting with the first to fourth corner cutting blades 46a to 46d may be performed first. Further, the first and second cutting blades 41 and 42 are first cut, and then the third and fourth corner cutting blades 46a and 46b are cut after the third cutting blade 43, and the fourth cutting is performed. After the cutting of the blade 44, cutting by the third and fourth corner cutting blades 46c and 46d may be performed. In addition to these, the cutting order by each cutting blade can be rearranged arbitrarily.

The configurations of the third and fourth cutting blades 43 and 44 are arbitrary, and in the same way as the first and second cutting blades 41 and 42 and the first to fourth corner cutting blades 46a to 46d described in the first embodiment, shearing is performed. Known cutting blades such as blades and Thomson blades can be used.

The relative positioning of the workpiece (electrode substrate 30, first and second electrode substrate pieces 31a, 31b) and the cutting blade may be such that only one of the workpiece and the cutting blade is moved. , You may move both.

The second embodiment is the same as the first embodiment except for the above. The description of the first embodiment is applied to the second embodiment as it is or after being appropriately changed.

(Embodiment 3)
In the third embodiment, a laminated lithium ion secondary battery provided with the sheet electrode of the present invention will be described.

FIG. 8 is a perspective plan view showing a schematic configuration of a lithium ion secondary battery 60 according to Embodiment 3 of the present invention.

In FIG. 8, 61p is a positive electrode, 61n is a negative electrode, and these positive electrode 61p and negative electrode 61n are the sheet-like electrodes of the present invention manufactured according to the method described in the first or second embodiment. . As described in the first and second embodiments, the positive electrode 61p and the negative electrode 61n include a substantially rectangular electrode portion and a tab portion protruding from one side of the electrode portion. 62p is a tab portion of the positive electrode 61p, and 62n is a tab portion of the negative electrode 61n. 63p is a positive electrode lead body, 63n is a negative electrode lead body, 64p is a positive electrode terminal, and 64n is a negative electrode terminal. One end of the positive electrode lead body 63p is connected to the positive electrode tab portion 62p, and the other end is connected to the positive electrode terminal 64p. One end of the negative electrode lead body 63n is connected to the negative electrode tab portion 62n, and the other end is connected to the negative electrode terminal 64n. 66 is a separator disposed between the positive electrode 61p and the negative electrode 61n, and 68 is a laminate sheet (exterior material) of the lithium ion secondary battery 60. A region 69 along the outer peripheral edge of the laminate sheet 68 is a heat seal portion where the front and back laminate sheets 68 are heat-sealed.

The positive electrode 61p has, for example, a structure in which a layer (positive electrode mixture layer) made of a positive electrode mixture containing a positive electrode active material, a conductive additive, a binder and the like is formed on one side or both sides of the current collector.

A positive electrode active material consists of an active material which can occlude / release lithium ion. Such a positive electrode active material includes, for example, lithium having a layered structure represented by Li _{1 + x} MO ₂ (−0.1 <x <0.1, M: Co, Ni, Mn, Al, Mg, etc.) Transition metal oxide, LiMn ₂ O ₄ , lithium manganese oxide having a spinel structure in which part of the element is replaced with another element, and olivine type represented by LiMPO ₄ (M: Co, Ni, Mn, Fe, etc.) It preferably consists of any one of compounds.

Lithium-containing transition metal oxide of the above layered structure, for _{example, LiCoO 2, LiNi 1-x} Co xy Al y O 2 (0.1 ≦ x ≦ 0.3,0.01 ≦ y ≦ 0.2), And an oxide containing at least Co, Ni and Mn (LiMn _1/3 Ni _1/3 Co _1/3 O ₂ , LiMn _5/12 Ni _5/12 Co _1/6 O ₂ , LiNi _3/5 Mn _1/5 Co _1/5 O ₂ or LiNi _0.5 Co _0.2 Mn _0.3 ) is preferable.

The current collector of the positive electrode 61p is preferably made of, for example, an aluminum foil or an aluminum alloy foil. The thickness of the current collector varies depending on the size and capacity of the battery, but is preferably 0.01 to 0.02 mm, for example.

The positive electrode 61p is manufactured by the following method. A positive electrode mixture containing the above-described positive electrode active material, a conductive additive such as graphite, acetylene black, carbon black, and fibrous carbon, and a binder such as polyvinylidene fluoride (PVDF) is used as N-methyl-2-pyrrolidone. A paste-like or slurry-like composition uniformly dispersed using a solvent such as (NMP) is prepared (the binder may be dissolved in the solvent). This composition is intermittently applied onto a strip-shaped current collector and dried, and the thickness of the positive electrode mixture layer is adjusted by pressing as necessary. The long positive electrode substrate (electrode substrate) thus obtained is cut into a predetermined shape by the method of Embodiments 1 and 2 described above to obtain the positive electrode 61p.

The thickness of the positive electrode mixture layer in the positive electrode 61p is preferably 30 to 100 μm per side. In addition, the content of each component in the positive electrode mixture layer is preferably positive electrode active material: 90 to 98% by mass, conductive assistant: 1 to 5% by mass, and binder: 1 to 5% by mass.

The positive electrode lead body 63p is preferably made of aluminum or an aluminum alloy. The thickness of the positive electrode lead body 63p is preferably 20 to 300 μm.

The material of the positive electrode terminal 64p is determined from the viewpoint of facilitating connection with a device using the battery 60. For example, aluminum or an aluminum alloy can be used.

The thickness of the positive electrode terminal 64p is preferably 50 to 300 μm. When the thickness of the positive electrode terminal 64p is 50 μm or more, the positive electrode terminal 64p can be prevented from being cut during welding of the positive electrode terminal 64p, and the positive electrode terminal 64p can be prevented from being broken by being pulled and bent. Moreover, when the thickness of the positive electrode terminal 64p is 300 μm or less, it is possible to prevent a gap from being generated between the positive electrode terminal 64p and the laminate sheet 68 in the heat seal portion 69 of the laminate sheet 68.

In order to increase the adhesive strength between the positive electrode terminal 64p and the laminate sheet 68, a resin adhesive layer (for example, the laminate sheet 68) is provided in advance in a region that is expected to be located in the heat seal portion 69 of the positive electrode terminal 64p. An adhesive layer made of the same kind of resin as the heat-fusible resin layer may be provided.

The connection method between the positive electrode tab portion 62p and the positive electrode lead body 63p and the connection method between the positive electrode lead body 63p and the positive electrode terminal 64p are, for example, resistance welding, ultrasonic welding, laser welding, caulking, adhesion by a conductive adhesive. Various methods can be employed. Among these, ultrasonic welding is preferable.

The negative electrode 61n has, for example, a structure in which a layer containing a negative electrode active material capable of inserting and extracting lithium ions (negative electrode mixture layer) is formed on one side or both sides of a current collector.

Negative electrode active materials include graphite, pyrolytic carbons, cokes, glassy carbons, fired organic polymer compounds, mesocarbon microbeads (MCMB), and carbon that can occlude and release lithium ions such as carbon fibers. It is preferable that it consists of 1 type, or 2 or more types of mixtures of system material.

Alternatively, the negative electrode active material may be an element such as Si, Sn, Ge, Bi, Sb, or In, an alloy of Si, Sn, Ge, Bi, Sb, or In, a lithium-containing nitride, or a lithium metal such as lithium oxide. It is preferably made of any of a compound (LiTi ₃ O ₁₂ or the like) that can be charged and discharged at a near low voltage, lithium metal, and a lithium / aluminum alloy.

As the current collector of the negative electrode 61n, copper foil is suitable. The thickness of the current collector varies depending on the size or capacity of the battery, but is preferably 0.005 to 0.02 mm, for example.

The negative electrode 61n is manufactured by the following method. The negative electrode active material described above, a binder (such as a mixed binder of rubber binder such as PVDF or styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC)), and graphite, acetylene black, carbon black, etc. A paste-like or slurry-like composition in which a negative electrode mixture containing a conductive aid or the like is uniformly dispersed using a solvent such as NMP or water is prepared (the binder may be dissolved in the solvent). . A long negative electrode base material (electrode base material) obtained by intermittently applying this composition onto a strip-shaped current collector is cut into a predetermined shape by the method of Embodiments 1 and 2, and the negative electrode is obtained. 61n are obtained. You may adjust the thickness or density of a negative mix layer by press processing as needed.

The thickness of the negative electrode mixture layer in the negative electrode 61n is preferably 30 to 100 μm per side. The content of each component in the negative electrode mixture layer is preferably negative electrode active material: 90 to 98% by mass and binder: 1 to 5% by mass. In the case where a conductive assistant is used, the content of the conductive assistant in the negative electrode mixture layer is preferably 1 to 5% by mass.

The negative electrode lead body 63n is preferably made of copper. The thickness of the negative electrode lead body 63n is preferably 20 to 300 μm.

The material of the negative electrode terminal 64n is determined from the viewpoint of facilitating connection with a device using the battery 60. For example, nickel, nickel-plated copper, nickel-copper clad, and the like can be used.

The thickness of the negative electrode terminal 64n is preferably 50 to 300 μm, like the positive electrode terminal 64p. When the thickness of the negative electrode terminal 64n is 50 μm or more, the negative electrode terminal 64n can be prevented from being cut during welding of the negative electrode terminal 64n, and the negative electrode terminal 64n can be prevented from being broken by being pulled and bent. Moreover, when the thickness of the negative electrode terminal 64n is 300 μm or less, it is possible to prevent a gap from being generated between the negative electrode terminal 64n and the laminate sheet 68 in the heat seal portion 69 of the laminate sheet 68.

In order to increase the adhesive strength between the negative electrode terminal 64n and the laminate sheet 68, a resin adhesive layer (for example, the laminate sheet 68) is provided in advance in a region that is planned to be located in the heat seal portion 69 of the negative electrode terminal 64n. An adhesive layer made of the same kind of resin as the heat-fusible resin layer may be provided.

The connection method between the negative electrode tab 62n and the negative electrode lead body 63n, and the connection method between the negative electrode lead body 63n and the negative electrode terminal 64n are, for example, resistance welding, ultrasonic welding, laser welding, caulking, and adhesion using a conductive adhesive. Various methods can be employed. Among these, ultrasonic welding is preferable.

The separator 66 includes a porous film that separates the positive electrode 61p and the negative electrode 61n and transmits lithium ions. The separator 66 preferably has a safety mechanism (shutdown characteristic) that melts and closes the hole when the battery 60 abnormally generates heat and reaches a high temperature (for example, 100 to 140 ° C.). From such a viewpoint, the porous film is preferably made of a thermoplastic resin having a melting point of about 80 to 140 ° C., and specifically, preferably made of a polyolefin polymer such as polypropylene or polyethylene. The thickness of the porous film is not particularly limited, but is preferably 10 to 50 μm.

The separator 66 may be formed by coating a plate-like inorganic fine particle layer on the porous film. Thereby, the thermal contraction of the separator 66 at the time of abnormal heat generation can be suppressed, and safety can be improved.

Alternatively, the separator 66 may have a laminated structure of the porous film and the heat-resistant porous substrate. As the heat resistant porous substrate, for example, a fibrous material having a heat resistant temperature of 150 ° C. or higher can be used. The fibrous material may be formed of at least one material selected from the group consisting of cellulose and its modified products, polyolefin, polyethylene terephthalate, polybutylene terephthalate, polypropylene, polyester, polyacrylonitrile, aramid, polyamideimide, and polyimide. it can. Specifically, it is preferably made of a nonwoven fabric made of the above materials.

“Heat resistance” of a porous substrate means that substantial dimensional change due to softening or the like does not occur. Specifically, is the upper limit temperature (heat resistant temperature) at which the rate of shrinkage (shrinkage ratio) with respect to the length of the porous substrate at room temperature maintained at 5% or less is sufficiently higher than the shutdown temperature of the separator? The heat resistance is evaluated based on the result. In order to increase the safety of the laminated battery after shutdown, it is desirable that the porous substrate has a heat resistance higher by 20 ° C. than the shutdown temperature. More specifically, the heat resistance temperature of the porous substrate is 150 ° C. It is preferable that the temperature is higher than or equal to ° C, and more preferable that the temperature is higher than or equal to 180 ° C.

As the electrolytic solution, for example, a solution (nonaqueous electrolytic solution) in which a solute such as LiPF ₆ or LiBF ₄ is dissolved in a high dielectric constant solvent or an organic solvent can be used. As the high dielectric constant solvent, any of ethylene carbonate (EC), propylene carbonate (PC), and γ-butyrolactone (BL) can be used. As the organic solvent, a low viscosity solvent such as linear dimethyl carbonate (DMC), diethyl carbonate (DEC), or methyl ethyl carbonate (EMC) can be used.

As the solvent for the electrolytic solution, it is preferable to use a mixed solvent of the above-described high dielectric constant solvent and low viscosity solvent. Alternatively, PVDF, a rubber-based material, an alicyclic epoxy, a material having an oxetane-based three-dimensional crosslinked structure, and the like may be mixed and solidified into the above-described solution to form a polymer electrolyte.

The separator 66 is interposed between the positive electrode 61p and the negative electrode 61n, and the positive electrode 61p and the negative electrode 61n are alternately stacked to form an electrode laminate.

The method for producing the electrode laminate is not particularly limited. For example, as shown in FIG. 9, the separator 66 is folded zigzag by alternately repeating a mountain fold and a valley fold at regular intervals, and the positive electrode 61p is sandwiched between each surface of the separator 66 from each side. The negative electrode 61n is sandwiched between the other surface side and each valley fold. At this time, the positive electrode tab portion 62p and the negative electrode tab portion 62n protrude outside from the same side of the separator 66. Alternatively, a plurality of rectangular bags formed by the separators 66 and the positive electrodes 61p inserted into the respective bags made of the separators 66 may be alternately stacked with the negative electrodes 61n.

The positive electrode lead body 63p is connected to the positive electrode tab portions 62p of the plurality of positive electrode electrodes 61p protruding from the electrode laminate thus obtained, and the positive electrode terminal 64p is connected to the positive electrode lead body 63p. Similarly, the negative electrode lead body 63n is connected to the negative electrode tab portions 62n of the plurality of negative electrode electrodes 61n protruding from the electrode laminate, and the negative electrode terminal 64n is connected to the negative electrode lead body 63n.

Two substantially rectangular laminate sheets 68 are arranged above and below the electrode laminate thus obtained, and two laminate sheets 68 are formed along three sides excluding the sides where the positive electrode terminal 64p and the negative electrode terminal 64n are formed. The laminate sheet 68 is formed into a bag shape by heat sealing. Rather than using two laminate sheets, one rectangular laminate sheet is folded and overlapped so as to sandwich the electrode laminate, and the laminated sheet 68 is heat-sealed along two sides and laminated sheet 68 may be formed in a bag shape. Thereafter, an electrolytic solution is injected into the bag of the laminate sheet 68. Finally, the laminate sheet 68 is heat-sealed together with a part of the positive and negative electrode lead bodies 63p and 63n and a part of the positive and negative electrode terminals 64p and 64n along the non-heat-bonded side. An ion secondary battery 60 is obtained.

The configuration of the laminate sheet 68 is not particularly limited, and for example, a known laminate sheet that is used as an exterior material of a laminated lithium ion secondary battery can be used. For example, a multilayer sheet in which a modified polyolefin layer is laminated as a heat-fusible resin layer on one side of a base layer made of aluminum can be used.

The above lithium ion secondary battery 60 is merely an example, and the lithium ion secondary battery using the positive electrode sheet electrode and the negative electrode sheet electrode of the present invention is not limited to the above. For example, the positive electrode sheet electrode and the negative electrode sheet electrode of the present invention can be applied to a known lithium ion secondary battery.

In the above example, the positive terminal 64p and the negative terminal 64n are drawn from the same short side of the substantially rectangular laminate sheet 68, but may be drawn from different sides.

In the above, an example of a laminated lithium ion secondary battery has been described. However, the sheet-like electrode of the present invention can be used for a lithium ion secondary battery other than the laminated type.

(Examples 1 and 2)
Laminated lithium ion secondary batteries according to Examples 1 and 2 having different dimensions only were manufactured as follows.

<Manufacture of sheet electrode for negative electrode>
A sheet-like electrode for the negative electrode was produced as follows.

A long length in which electrode regions and non-electrode regions are alternately formed by intermittently applying an electrode mixture containing a negative electrode active material at a constant pitch to corresponding regions on both sides of a strip-shaped current collector made of copper foil An electrode substrate 30n for the negative electrode was prepared. FIG. 10A is a perspective view of a pancake around which the electrode substrate 30n is wound, and FIG. 10B is a plan view of a part of the electrode substrate 30n for the negative electrode. The width W30n of the electrode substrate 30n according to Examples 1 and 2, the length L35n of the electrode substrate 30n in the longitudinal direction of the electrode region 35n where the negative electrode mixture layer is formed, and the length of the electrode substrate 30n of the non-electrode region 37n Each value of the direction length L37n is also shown in FIG. 10B. Example 1 and Example 2 differ only in the width W30n of the electrode base material 30n.

10A and 10B, the electrode substrate 30n was cut at a constant pitch along the broken line 41n in FIG. 10B while intermittently unwinding the long electrode substrate 30n shown in FIG. 10B from the pancake. A broken line 41n indicates the first cutting blade for the negative electrode, and the shape of the cutting blade is shown in FIG. 20A. As shown in FIG. 20A, the first cutting blade 41n had a stepped cutting blade shape. Each value of the level difference Hn of the first cutting blade 41n and the cuttable width W41n is also shown in FIG. 20A. In Examples 1 and 2, the same first cutting blade 41n was used. The first cutting blade 41n was fixed to the lifting member of the punching device. The relative position in the width direction of the first cutting blade 41n with respect to the electrode substrate 30n is the width W27n of the tab portion 27n of the negative electrode sheet electrode of Examples 1 and 2 to be finally obtained (FIG. 11, which will be described later). (See FIG. 13). Since the width W27n is different between the first embodiment and the second embodiment, the mounting position of the first cutting blade 41n with respect to the lifting member is changed between the first embodiment and the second embodiment.

FIG. 11 is a plan view of the first electrode substrate piece 31n-1 for negative electrode obtained by cutting the electrode substrate 30n for negative electrode with the first cutting blade 41n for negative electrode at a pitch Pn. The dimensions of each part are also shown in FIG. Example 1 and Example 2 differ in the width W27n of the tab portion.

The first electrode substrate piece 31n-1 was cut along the broken line 42 shown in FIG. The broken line 42 indicates the second cutting blade, and the shape of the cutting blade is shown in FIG. 20B. As shown in FIG. 20B, the second cutting blade 42 had a linear cutting blade shape. The value of the cuttable width W42 of the second cutting blade 42 is also shown in FIG. 20B. In Examples 1 and 2, the same second cutting blade 42 was used. The second cutting blade 42n was fixed to the lifting member of the punching device. The position of the second cutting blade 42 in the longitudinal direction relative to the first electrode substrate piece 31n-1 is the length L20n of the electrode portion 20n of the negative electrode sheet electrode of Examples 1 and 2 to be finally obtained (described later) (See FIG. 13). Since the length L20n is different between the first embodiment and the second embodiment, the mounting position of the second cutting blade 42n with respect to the lifting member is changed between the first embodiment and the second embodiment.

FIG. 12 is a plan view of the second electrode substrate piece 31n-2 for negative electrode obtained by cutting the first electrode substrate piece 31n-1 for negative electrode with the second cutting blade 42. FIG.

Next, the three corners 125n-a, 125n-b, and 125n-c of the electrode region 35n of the second electrode substrate piece 31n-2 shown in FIG. 12 (the portion that will later become the electrode portion 20n) are represented by broken lines 146a, 146b, It cut off into circular arc shape along 146c. Dashed lines 146a, 146b, and 146c indicate corner cutting blades used for cutting the corners 125n-a, 125n-b, and 125n-c, and the shapes of the cutting blades are shown in FIGS. 21A, 21B, and 21C. Each of the corner cutting blades 146a, 146b, and 146c had an arc shape with a radius R of 20 mm and a central angle θc of 90 degrees. In Examples 1 and 2, the same corner cutting blades 146a, 146b, and 146c were used. The corner cutting blades 146a, 146b, 146c were fixed to the same lifting member of the punching device. The mounting positions of the corner cutting blades 146a, 146b, and 146c with respect to the lifting member are changed between the first and second embodiments in accordance with the positions of the corners 125n-a, 125n-b, and 125n-c.

Thus, a negative electrode sheet electrode (negative electrode) 1n shown in FIG. 13 was obtained. The dimension of each part of the sheet-like electrode 1n of Examples 1 and 2 is shown together in FIG.

14A, 14B, and 14C are enlarged plan views of the portions 14A, 14B, and 14C of FIG. 13 including the three corner portions 125n-a, 125n-b, and 125n-c of the electrode portion 20n. The width direction dimension Wa of the arc defined by the central angle θa of the arcs 126n-a, 126n-b, 126n-c formed at the corners 125n-a, 125n-b, 125n-c, and both ends of the arc. The values of the longitudinal dimension La are also shown in FIGS. 14A, 14B, and 14C. These are the same in Example 1 and Example 2.

In the above-described Example 1 and Example 2, the dimensions of the prepared sheet-like electrode 1n are different from each other. However, the first cutting blade 41n, the second cutting blade 42, and the corner cutting blades 146a, 146b, and 146c used in the process of manufacturing the sheet electrode 1n of Example 1 and the sheet electrode 1n of Example 2 are the same. there were. As described above, in the first and second embodiments, the same cutting blade is used, and the size of the first and second embodiments is different only by changing the mounting position of the cutting blade with respect to the lifting member according to the size of the sheet-like electrode 1n. The sheet-like electrode 1n was able to be manufactured.

<Manufacture of sheet-like electrode for positive electrode>
A sheet-like electrode for a positive electrode was produced as follows.

A long length in which electrode regions and non-electrode regions are alternately formed by intermittently applying an electrode mixture containing a positive electrode active material at a constant pitch to corresponding regions on both sides of a strip-shaped current collector made of aluminum foil An electrode substrate 30p for the positive electrode was prepared. FIG. 15A is a perspective view of a pancake around which the electrode substrate 30p is wound, and FIG. 15B is a plan view of a part of the electrode substrate 30p for positive electrode. The width W30p of the electrode base material 30p according to Examples 1 and 2, the length L35p in the longitudinal direction of the electrode base material 30p in the electrode region 35p on which the positive electrode mixture layer is formed, and the length of the electrode base material 30p in the non-electrode region 37n Each value of the direction length L37p is also shown in FIG. 15B. Example 1 and Example 2 differ only in the width W30p of the electrode base material 30p.

The electrode substrate 30p was cut at a constant pitch along the broken line 41p in FIG. 15B while intermittently unwinding the long electrode substrate 30p shown in FIGS. 15A and 15B from the pancake. The broken line 41p shows the first cutting blade for the positive electrode, and the shape of the cutting blade is shown in FIG. 20C. As shown in FIG. 20C, the first cutting blade 41p had a stepped cutting blade shape. Each value of the level difference Hp of the first cutting blade 41p and the cuttable width W41p is also shown in FIG. 20C. In Examples 1 and 2, the same first cutting blade 41p was used. The 1st cutting blade 41p was fixed to the raising / lowering member of the punching apparatus. The relative position in the width direction of the first cutting blade 41p with respect to the electrode substrate 30p is the width W27p of the tab portion 27p of the positive electrode sheet-like electrode of Examples 1 and 2 to be finally obtained (FIG. (See FIG. 18). Since the width W27p is different between the first embodiment and the second embodiment, the mounting position of the first cutting blade 41p with respect to the lifting member is changed between the first embodiment and the second embodiment.

FIG. 16 is a plan view of the first electrode substrate piece 31p-1 for positive electrode obtained by cutting the electrode substrate 30p for positive electrode with the first cutting blade 41p for positive electrode at the pitch Pp. The dimensions of each part are also shown in FIG. Example 1 and Example 2 differ in the tab portion width W27p.

The first electrode substrate piece 31p-1 was cut along the broken line 42 shown in FIG. The broken line 42 indicates the second cutting blade, and the shape of the cutting blade is shown in FIG. 20B. In Examples 1 and 2, the same second cutting blade 42 was used. The second cutting blade 42 is the same as the second cutting blade 42 (see FIG. 11) used when cutting the first electrode substrate piece 31n-1 for negative electrode. The 2nd cutting blade 42p was fixed to the raising / lowering member of the punching apparatus. The position of the second cutting blade 42 in the longitudinal direction relative to the first electrode substrate piece 31p-1 is the length L20p of the electrode portion 20p of the positive electrode sheet-like electrode of Examples 1 and 2 to be finally obtained (described later). (See FIG. 18). Since the length L20p is different between the first embodiment and the second embodiment, the mounting position of the second cutting blade 42p with respect to the lifting member is changed between the first embodiment and the second embodiment.

FIG. 17 is a plan view of the second electrode substrate piece 31p-2 for positive electrode obtained by cutting the first electrode substrate piece 31p-1 for positive electrode with the second cutting blade 42. FIG.

Next, the three corners 125p-b, 125p-c, and 125p-d of the electrode region 35p (the portion that will later become the electrode portion 20p) of the second electrode substrate piece 31p-2 shown in FIG. 17 are represented by broken lines 146b, 146c, It cut off into circular arc shape along 146d. Dashed lines 146b, 146c, and 146d indicate corner cutting blades used for cutting the corners 125p-b, 125p-c, and 125p-d, and the cutting blade shapes are shown in FIGS. 21B, 21C, and 21D. Each of the corner cutting blades 146b, 146c, and 146d had an arc shape with a radius R of 20 mm and a central angle θc of 90 degrees. In Examples 1 and 2, the same corner cutting blades 146b, 146c, and 146d were used. The corner cutting blades 146b and 146c are the same as the corner cutting blades 146b and 146c (see FIG. 12) used when cutting the corner portions 125n-b and 125n-c of the second electrode base material piece 31n-2 for negative electrode. It is. The corner cutting blades 146b, 146c, and 146d were fixed to the same lifting member of the punching device. The mounting positions of the corner cutting blades 146b, 146c, and 146d with respect to the lifting member are changed between the first and second embodiments in accordance with the positions of the corners 125p-b, 125p-c, and 125p-d.

Thus, a positive electrode sheet electrode (positive electrode) 1p shown in FIG. 18 was obtained. The dimension of each part of the sheet-like electrode 1p of Examples 1 and 2 is shown together in FIG.

19A, 19B, and 19C are enlarged plan views of portions 19A, 19B, and 19C of FIG. 18 including the three corners 125p-b, 125p-c, and 125p-d of the electrode portion 20p. The width direction dimension Wa of the arc defined by the central angle θa of the arcs 126p-b, 126p-c, 126p-d formed at the corners 125p-b, 125p-c, 125p-d and both ends of the arc. The values of the longitudinal dimension La are also shown in FIGS. 19A, 19B, and 19C. These are the same in Example 1 and Example 2.

In the above-described Example 1 and Example 2, the dimensions of the prepared sheet-like electrode 1p are different from each other. However, the first cutting blade 41p, the second cutting blade 42, and the corner cutting blades 146b, 146c, and 146d used in the process of manufacturing the sheet-like electrode 1p of Example 1 and the sheet-like electrode 1p of Example 2 are the same. there were. As described above, in the first and second embodiments, the same cutting blade is used, and the size of the first and second embodiments is different only by changing the mounting position of the cutting blade with respect to the lifting member according to the size of the sheet-like electrode 1p. The sheet-like electrode 1p was able to be manufactured.

<Manufacture of laminated lithium ion secondary batteries>
As described with reference to FIG. 9, the negative electrode sheet-like electrode 1n is sandwiched in each valley folded portion on one surface side of the separator 66 folded in a zigzag shape, and the above positive electrode is disposed in each valley folded portion on the other surface side. An electrode laminate 70 shown in FIG. 22 was obtained by sandwiching the sheet-like electrode 1p. In FIG. 22, reference numeral 72 denotes a tape for fixing each of the four sides of the electrode laminate 70.

The negative electrode terminal and the positive electrode terminal were connected to the negative electrode tab portion 27n and the positive electrode tab portion 27p of the electrode laminate 70 by a known method. Next, the electrode laminate 70 was housed in a bag-like laminate sheet together with the electrolytic solution and sealed to obtain laminated lithium ion secondary batteries of Examples 1 and 2.

As described above, it was possible to manufacture sheet-like electrodes having different sizes using the same cutting blades in Example 1 and Example 2.

Furthermore, in the first and second embodiments, the second cutting blade 42 and the corner cutting blades 146b and 146c can be used in common in the manufacture of the negative electrode sheet electrode 1n and the positive electrode sheet electrode 1p. Therefore, the number of types of cutting blades can be reduced.

The embodiments and examples described above are intended to clarify the technical contents of the present invention, and the present invention is not construed as being limited to such specific examples. Various modifications can be made within the spirit and scope of the present invention, and the present invention should be interpreted broadly.

The application field of the present invention is not particularly limited, and can be particularly preferably used in the field of secondary batteries in which sheet-like positive electrodes and sheet-like negative electrodes are alternately arranged via separators. In particular, it is suitable for secondary batteries that require various sizes.

DESCRIPTION OF SYMBOLS 1, 2 Sheet-like electrode 20 Electrode part 21 First side 22 of electrode part Second side 23 of electrode part First side edge 24 of electrode part Second side edge 25a, 25b, 25c, 25d of electrode part Corner portion 26 Arc 27 formed by corner cutting blades Tab portion 30 Electrode substrate 35 Electrode region 37 Non-electrode region 41 First cutting blade 42 Second cutting blade 43 Third cutting blade 44 Fourth cutting blades 46a, 46b, 46c , 46d Corner cutting blade 60 Lithium ion secondary battery 61p Positive electrode (sheet electrode for positive electrode)
61n Negative electrode (sheet electrode for negative electrode)
62p Tab portion of positive electrode 62n Tab portion of negative electrode 66 Separator 68 Exterior material (laminate sheet)

Claims (16)

1. An electrode mixture layer containing an active material is formed by cutting a long electrode base material formed intermittently in the longitudinal direction of the current collector on at least one surface of a strip-shaped current collector to form the electrode mixture layer A substantially rectangular electrode part, and a method of manufacturing a sheet-like electrode provided with a tab part including a region protruding from one side of the electrode part and not including the electrode mixture layer,
   Forming the tab portion of the sheet-like electrode and the first side from which the tab portion protrudes using a first cutting blade having a cuttable width longer than the width of the electrode substrate;
   Forming a second side opposite to the first side of the sheet-like electrode using a second cutting blade having a cutable width longer than the width of the electrode base material. Manufacturing method of the electrode.
2. The method for producing a sheet-like electrode according to claim 1, further comprising a step of adjusting the positions of the first cutting blade in the longitudinal direction and the width direction of the electrode base material.
3. The method for producing a sheet-like electrode according to claim 1 or 2, further comprising a step of adjusting the position of the second cutting blade in the longitudinal direction of the electrode base material.
4. The method for producing a sheet-like electrode according to any one of claims 1 to 3, wherein the width of the electrode substrate is the same as the width of the sheet-like electrode.
5. The method further comprises the step of forming at least one of the four corners of the sheet-like electrode in an arc shape using an arc-shaped corner cutting blade different from the first cutting blade and the second cutting blade. The manufacturing method of the sheet-like electrode in any one of.
6. The method for producing a sheet-like electrode according to claim 5, wherein a central angle of an arc formed at at least one of the four corners of the sheet-like electrode is less than 90 °.
7. The method for producing a sheet-like electrode according to claim 5 or 6, wherein an arc length of the corner cutting blade is longer than an arc length of an arc formed at a corner of the sheet-like electrode by the corner cutting blade.
8. The method for producing a sheet electrode according to any one of claims 5 to 7, wherein the sheet electrode is a sheet electrode for a negative electrode.
9. The method for producing a sheet-like electrode according to any one of claims 5 to 8, further comprising a step of adjusting a position of the corner cutting blade in the first side direction and a direction orthogonal thereto.
10. Forming at least one of the pair of side edges excluding the first side and the second side of the sheet-like electrode using a third cutting blade different from the first cutting blade and the second cutting blade; The method for producing a sheet-like electrode according to any one of claims 1 to 9, further comprising:
11. The sheet-like electrode manufacturing method according to claim 10, wherein a cuttable width of the third cutting blade is longer than the length of the at least one of the pair of side edges.
12. The method for producing a sheet-like electrode according to claim 10 or 11, further comprising a step of adjusting the position of the third cutting blade in the first side direction.
13. One of the pair of side edges is formed using the third cutting blade, and the other is a fourth cutting blade different from the first cutting blade, the second cutting blade, and the third cutting blade. The method for producing a sheet-like electrode according to any one of claims 10 to 12, wherein the method is used for cutting.
14. A sheet electrode manufactured using the method for manufacturing a sheet electrode according to any one of claims 1 to 13.
15. A lithium ion secondary battery comprising the sheet-like electrode according to claim 14.
16. The lithium ion secondary battery according to claim 15, which is a laminate type.

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