JP2018006138A - Electrode for power storage device, and power storage device employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode for a power storage device capable of reducing damage to be generated in a peripheral member even in the case where the vicinity of an apex of an electrode that is a rectangular sheet is abutted with the peripheral member, and a power storage device employing the same.SOLUTION: An electrode 10 for power storage device is a rectangular sheet and comprises end sides 11-14. A notch 20 is provided in an apex 15 of the end sides 11 and 12 at least, and a notch side 22 connected with each of the end side 11 and the end side 12 at a first connection point 24 and a second connection point 26 is included. When a line that is orthogonal to a bisector of an internal angle is defined as a straight line β at the first connection point 24, a projection part 30 surrounded by the straight line β and the notch line 22 or surrounded by the straight line β, the notch side 22 and the end side 12 is formed. A section 40 which is included in the notch side 22 and becomes an outer edge of the projection part 30 includes a curved line or a corner having an internal angle that is larger than the internal angle of the first connection point 24.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to an electrode for a power storage device and a power storage device using the same.

  As an electrode used for a power storage device, for example, an electrode in which an electrode mixture layer containing an electrode active material is formed on both surfaces of a current collector is known. Such an electrode can be produced by cutting a long current collector (electrode sheet) having an electrode mixture layer on the surface into predetermined dimensions according to the unit electrode to be produced.

  Patent Document 1 discloses an electrode sheet in which an electrode active material is applied to one side or both sides of a current collector sheet, and one side and the other side of the upper and lower sides of the electrode sheet have a width of a unit electrode plate. The first notch portion and the second notch portion are formed at corresponding intervals, and the second notch portion is smaller in size than the lower end cut side and has an upper end cut side for a cutting margin. A sheet and an electrode plate formed by cutting the electrode sheet are described.

Patent Application Publication No. 2015-528639

  When producing an electrode that is a rectangular sheet by cutting the electrode sheet, a sharp protrusion may be formed at the apex of the cut surface and the notch provided in the electrode in the vicinity of the apex of the rectangular sheet of the electrode. is there. Then, when the battery manufactured using the electrode is transported or used, the protrusion formed on the electrode when the electrode and the peripheral member of the electrode such as the separator and the electrode body cover come into contact with each other by an external force or the like. Therefore, it is considered that a strong stress is applied to the peripheral member, and the peripheral member is damaged, so that the performance of the power storage device may be deteriorated. Therefore, there is a demand for an electrode for a power storage device that can reduce damage to the peripheral member even when the vicinity of the apex of the electrode that is a rectangular sheet comes into contact with the peripheral member.

  The electrode for a power storage device according to the present disclosure is a rectangular sheet, and the rectangular sheet includes a first end side and a second end side orthogonal to the first end side, A notch is provided at the apex of the first end and the second end, and is formed by the notch, and each of the first end and the second end is connected to the first connection point and When there is a notched side connected at the second connection point, the bisector of the inner angle at the first connection point is a straight line α, and the line orthogonal to the straight line α at the first connection point is a straight line β The straight line β intersects the notch side to form a raised portion surrounded by the straight line β and the notch side, or surrounded by the straight line β, the notch side, and the second end side. The section that is included in the notch side and that is the outer edge of the raised portion has a curved line. Or characterized in that it has a corner portion having a larger interior angle than the interior angle of the first connection point.

  According to the electrode for the power storage device according to the present disclosure, even when the vicinity of the vertex of the electrode that is a rectangular sheet and the peripheral member abut, the raised portion formed in the notch provided at the vertex of the electrode By damaging the stress on the peripheral member, damage to the peripheral member can be reduced.

It is a figure which shows the electrode which is an example of embodiment. It is a figure which shows the notch provided in the electrode which is an example of embodiment. It is a figure which shows the notch provided in the electrode which is another example of embodiment. It is a figure which shows the notch provided in the electrode which is another example of embodiment. It is a figure which shows an example of the manufacture example of the electrode of embodiment. It is a figure which shows another example of the manufacture example of the electrode of embodiment. It is a figure which shows the notch | incision provided in the electrode sheet shown in FIG. It is a schematic diagram which shows the electrode assembly which is an example of embodiment.

  In a method for manufacturing an electrode used in a power storage device, a step of cutting a long and strip-shaped electrode sheet having an electrode mixture layer provided on the surface thereof according to the shape and dimensions of a unit electrode is generally performed. When cutting an electrode sheet, the technique which forms a notch part in the space | interval corresponding to the edge of a unit electrode in at least one of the edge | side of the longitudinal direction of an electrode sheet is known. By cutting so as to pass through the cut-out portion formed in this way, the cut-out single electrode plate is chamfered at the corners, and the formation of a sharp end can be suppressed. Therefore, electrochemical deterioration as a power storage device can be suppressed.

  In Patent Document 1, even if the electrode sheet is cut with a deviation from the design cutting line by providing an upper edge cut edge as a cutting margin at the notch portion of the electrode sheet, the upper edge cut edge passes through the upper edge cut edge. It is described that when cut, a projecting portion is not formed, and a unit electrode corresponding to the initial design shape can be manufactured. However, as shown in FIG. 1b of Patent Document 1, even if the cut is made by passing through the upper edge cut edge of the notch portion, a sharp protrusion is formed at the intersection of the cut surface and the notch portion. In this case, after manufacturing the power storage device, there is a possibility of damaging the member when receiving an external force and contacting a peripheral member.

  As a result of providing a notch portion having a specific shape at the apex of a rectangular electrode, the electrode for a power storage device according to the present disclosure has a peripheral member even if a protruding portion is formed by cutting the electrode sheet. It has been found that damage to peripheral members can be reduced by providing a raised portion having a function of buffering stress due to contact with the vicinity of the apex.

  Hereinafter, an example of an embodiment of the present disclosure will be described in detail with reference to the drawings. The power storage device electrode according to the present disclosure is not limited to the embodiments described below. Since the drawings referred to in the description of the embodiments are schematically described, the dimensional ratios of the components drawn in the drawings should be determined in consideration of the following description.

  FIG. 1 shows an example of an electrode for a power storage device (also simply referred to as “electrode”) 10 of the present embodiment. FIG. 1 shows the overall structure of the electrode 10.

  The electrode 10 is a sheet formed in a rectangular shape. The rectangular sheet has a first edge (edge 11), a second edge (edge 12), a third edge (edge 13), and a fourth edge (edge 14). Any one of the end side 11 and the end side 13 and either the end side 12 or the end side 14 intersect each other.

  Vertex 15 where end side 11 and end side 12 intersect, vertex 16 where end side 12 and end side 13 intersect, vertex 17 where end side 13 and end side 14 intersect, and end side 14 and end side Each of the vertices 18 intersecting with 11 is provided with a notch 20. Note that vertices 15 to 18 shown in the drawing are virtual points. The electrode 10 of the present embodiment may have a plurality of cutout portions 20, but is not limited thereto, and the function of the present embodiment can be achieved as long as it has at least one cutout portion 20. Can be obtained. It is preferable that the electrode 10 of this embodiment has the notch part 20 in all the vertexes of a rectangular sheet.

  The electrode 10 includes an electrode tab 50 protruding from one end side (for example, the end side 14 in FIG. 1) of the rectangular sheet. The electrode tab 50 is provided to be electrically connected to the outside of the battery.

  In this specification, the term “rectangular shape” for the electrode 10 may be a rectangular shape as a whole. For example, the notch portion 20 provided at the vertex 15 to the vertex 18 and the electrode tab provided at the end side 14. Used to include those having 50.

  FIG. 2 is an enlarged view of the vicinity of the vertex 15 where the end side 11 and the end side 12 intersect in the electrode 10 shown in FIG. A broken line in FIG. 2 is an extension line of the end side 11 and the end side 12, and the notch 20 is a region where the vertex 15 is notched. An outer edge portion of the electrode 10 formed by the notch 20 is defined as a notch side 22. The notch side 22 forms a boundary between the electrode 10 and the notch part 20, one end is connected to the end side 11 at the first connection point 24, and the other end is set to the end side 12 and the second connection point 26. Connecting.

  The straight line α and the straight line β are virtual lines. The straight line α is a bisector of the internal angle φ formed by the end side 11 and the cut-out side 22 at the first connection point 24. The straight line β is orthogonal to the straight line α at the first connection point 24. The vertex 15 is also a virtual point.

  The inner angle φ of the first connection point 24 varies depending on the shape of the notch 20. The cut-out side 22 has one end portion that is a first connection point 24 and has a straight portion 28 that is orthogonal to the first end side 11, that is, the internal angle φ of the first connection point 24 is 90 °. It is preferable. In the other unit electrode 62 separated by cutting the electrode sheet, the internal angle φ of the point facing the first connection point is also 90 °, both internal angles φ are not acute angles, and the stress applied to the peripheral members is minimized. Because it can.

  The shape of the notch 20 in the electrode 10 of this embodiment is formed so that the straight line β intersects the notch side 22. Therefore, a part of the electrode 10 is divided by the straight line β. In the present embodiment, a region surrounded by the straight line β and the notch side 22, or a region surrounded by the straight line β, the notch side 22, and the second end side 12, which is a region divided by the straight line β of the electrode 10. , A raised portion 30.

  In the electrode 10 shown in FIG. 2, the straight line β intersects with the notch side 22 at the intersection point 32 and intersects with the end side 12 at the intersection point 34. The region is surrounded by the side 22 and the second end side 12.

  In another example of the electrode 10 of the present embodiment shown in FIG. 3, the straight line β intersects the cut-out side 22 at two points of the intersection point 36 and the intersection point 38. The region is surrounded by the cut-out side 22.

  The section 40 is a portion that forms the outer edge of the raised portion 30 excluding the straight line β, and is included in either the notch side 22 or the end side 12. The section 40 has a curved line or a corner having an inner angle θ larger than the inner angle φ of the first connection point 24. The section 40 may be composed of only a straight line, may be composed of only a curved line, or may be composed of a combination of a straight line and a curved line.

  When the electrode 10 abuts on another member at the first connection point 24, the stress between the first connection point 24 and the other member is maximum when the abutting direction is a direction along the straight line α. Become. In the electrode 10 of the present embodiment, at the apex 15 where the notch 20 is provided, there is a raised portion 30 formed outside the straight line β that passes through the first connection point 24 and is orthogonal to the straight line α. The raised portion 30 functions as a buffer portion of the first connection point 24 and disperses the stress applied to the first connection point. Therefore, the raised portion 30 does not have the raised portion 30 and is formed at a right angle or an acute angle formed at the first connection point. Compared with the case where stress is applied to the portion, it is considered that the possibility of damage to the peripheral member and the degree of damage to be generated can be significantly reduced.

  The section 40 has at least a first section 41 included in the cut-out side 22 and may have a second section 42 included in the end side 12 in some cases. As shown in FIG. 2, when the straight line β intersects with the end side 12, the section 40 has the second section 42, but as shown in FIG. 3, the straight line β intersects only with the notch side 22 and the end side If it does not cross 12, the section 40 does not have the second section 42. In addition, since the 2nd area 42 is contained in the end side 12, it is comprised by the straight line.

  In another example of the electrode 10 of this embodiment shown in FIG. 4, the straight line β intersects each of the cut-out side 22 and the end side 12 at the intersection point 32 and the intersection point 34, and the first section 41 (the intersection point 32 and the second connection). (Between point 26) is composed of only a curve.

  The electrode 10 of the present embodiment may have a plurality of raised portions 30 depending on the shape of the cutout portion 20. The electrode 10 includes, for example, one or a plurality of ridges 30 surrounded by a straight line β and a notch side 22, and one ridge 30 surrounded by a straight line β, the notch side 22, and the second end side 12. You may have.

  The corners of the section 40 include, for example, the corners of the first section 41 in FIGS. 2 and 3 and the corners constituted by the cut-out side 22 and the end side 12 at the second connection point 26. Is mentioned. When the section 40 has a corner, from the viewpoint of buffering stress on the peripheral member, the inner angle θ (θ1 and θ2 in FIG. 2 and θ1 in FIG. 3) of the corner is at least the inner angle φ of the first connection point 24. It is preferably larger, more preferably 100 ° or more, and further preferably 120 ° or more.

  When the section 40 includes a curve, from the viewpoint of buffering stress on the peripheral member, when the section 40 has a convex portion that protrudes toward the outside of the electrode 10, the curvature radius of the convex portion may be 0.1 mm or more. preferable. For example, it is preferable that the curve included in the section 40 has an arc line portion that is convex toward the outside of the electrode 10, and as a specific example, as illustrated in FIG. 4, over the entire length of the first section 41, A mode in which a gentle arc line portion that protrudes toward the outside of the electrode 10 is formed.

  Further, the section 40 does not have a corner portion whose inner angle θ is an acute angle (less than 90 °), and has a convex portion that protrudes toward the outside of the electrode 10 and has a curvature radius of 0.1 mm or less. Preferably not. This is because the function of buffering stress on the peripheral member may be reduced.

  The first section 41 is preferably configured by a curve or has a corner portion having an inner angle θ larger than the inner angle φ of the first connection point 24. In particular, when the peripheral member and the cut-out side 22 are in surface contact, it is possible to suppress contact under the condition that the stress applied from the first connection point 24 is maximized, and damage to the peripheral member can be reduced. It is.

  When the straight line β intersects the end side 12 and the raised portion 30 is an area surrounded by the straight line β, the cut-out side 22 and the end side 12, one end of the first section 41 is the second connection point. It is preferable to have a straight portion 44 that is 26 and include a curve or a corner portion having an inner angle θ larger than the inner angle φ of the first connection point 24. Since the raised portion 30 is widely provided and the raised portion 30 has a plurality of corners, even if the angle with which the peripheral member abuts is wide, the stress applied to the peripheral member by the first connection point 24 The function of buffering can be exhibited, and the possibility of damage to peripheral members can be further reduced. Furthermore, as will be described later, it is possible to improve the accuracy when the notch 20 is notched. In addition, when the shape of the notch side 22 connected to the second connection point 26 is a curve, the maximum value of the inner angle between the tangent of each part of the curve and the end side 12 is set as the inner angle of the second connection point 26. To do.

  FIG. 2 is a specific example of the preferred embodiment described above, and the raised portion 30 shown in FIG. 2 has an intersection point 32 and a second connection point 26 that are closest to the first connection point 24 among the intersection points of the straight line β and the notch side 22. And a second corner provided at the second connection point 26. Thus, when the protruding part 30 has a some corner | angular part, since it is excellent by the function which buffers the stress to a peripheral member, it is preferable.

  Although the specific example of the dimension of the notch part 20 is described, the notch part 20 which the electrode 10 of this embodiment can have is not limited to the following specific examples.

  In the cutout portion 20, the length from the vertex 15 to the first connection point 24 can be, for example, 5% or more and 30% or less with respect to the length of the end side 11. Moreover, the length from the vertex 15 to the 1st connection point 24 can be 5 mm or more and 20 mm or less, for example.

  In the cutout portion 20, the length from the vertex 15 to the second connection point 26 can be, for example, 2% or more and 20% or less with respect to the length of the end side 12. The length from the vertex 15 to the second connection point 26 can be, for example, 2 mm or more and 10 mm or less. The length from the vertex 15 to the second connection point 26 is preferably shorter than the length from the vertex 15 to the first connection point 24. For example, the length from the vertex 15 to the first connection point 24 is 60. % Or less is more preferable.

  As described above, it is preferable that the cut-out side 22 has the first connection point 24 at one end and the straight portion 28 orthogonal to the first end 11. The length of the straight line portion 28 differs depending on how much a cutting margin is provided in the design when the electrode sheet 60 is cut into the shape of the predetermined unit electrode 62, but is, for example, 0.5 mm or more and 2.5 mm or less. be able to.

  In the notch 20, the section from the end of the straight line portion 28 opposite to the first connection point 24 to the second connection point 26 can buffer the stress applied to the peripheral member provided by the first connection point 24. Thus, it is preferable that the raised portion 30 has a certain height and has a shape that is not sharper than the inner angle φ of the first connection point 24.

  For example, as shown in FIGS. 2 and 3, in the notch portion 20, the straight portion 28 passes through the end portion of the straight portion 28 opposite to the first connection point 24, and is orthogonal to the straight portion 28. A longer straight portion 46 may be formed. The cut-out side 22 may include a straight portion 44 having the second connection point 26 as one end, as shown in FIGS. 2 and 3, and as shown in FIG. A curve (for example, an arc line portion) having the connection point 26 as one end portion may be included.

  When the section 40 has a corner, the notch side 22 may have a straight portion between the apex of the corner and the second connection point 26. Further, when the section 40 has a curve, the notch side 22 may have a straight line portion between an end portion close to the second connection point and both ends of the curve. When the peripheral member comes into contact with the straight portions provided in these regions, the peripheral member is likely to be in line contact with the raised portion 30 instead of being in point contact when the raised portion 30 and the peripheral member are in contact with each other. Therefore, it is possible to make it difficult to cause contact at the first connection point 24 that may be caused by, for example, turning of the peripheral member or the electrode 10 after the peripheral member contacts the raised portion 30 once.

  In the electrode 10 of the present embodiment, the number of places where the possibility of damage to the peripheral members is increased. Therefore, in addition to the apex 15 of the end side 11 and the end side 12, in addition to the apex 15 of the end side 13 and the end side 12 However, it is preferable that the notch 20 is provided. In this case, the shape of the notch 20 provided at the vertex 15 and the shape of the notch 20 provided at the vertex 16 are axisymmetric with each other.

  As shown in FIG. 1, the electrode 10 of the present embodiment is particularly preferably provided with cutout portions 20 at four corners of a rectangular sheet. This is because the function of buffering stress can be imparted to all of the apex portions of the rectangular sheet that are likely to damage the peripheral member when coming into contact with the peripheral member. In this case, it is preferable that the shapes of the notches 20 sharing one end side are symmetrical with each other. In addition, the electrode 10 of this embodiment is not limited to the one provided with the four notches 20, and the notch 20 has at least one apex portion (for example, the apex 15 of the end side 11 and the end side 12. ) Is effective in reducing damage to peripheral members.

  An example of manufacturing the electrode 10 of the present embodiment will be described with reference to FIG. A band-shaped current collector is prepared, and a slurry in which an electrode active material and a dispersion medium are mixed is applied to at least one surface thereof, and dried to form an electrode mixture layer. Next, by pressing the formed electrode mixture layer, as shown in FIG. 5A, a strip-shaped electrode sheet having a rectangular region (a mixture layer region 74) in which the electrode mixture layer is formed. 60 is obtained.

  The composite material layer region 74 in the electrode sheet 60 includes one side 70 along the longitudinal direction, and extends in the longitudinal direction. The electrode sheet 60 further includes a current collector exposed region 76 that extends in the longitudinal direction including the other side 68 along the longitudinal direction. In the current collector exposed region 76, the electrode mixture layer is not formed, and the surface of the current collector is exposed. The electrode sheet 60 shown in FIG. 5A has a configuration in which unit electrodes 62 delimited by virtual cutting lines 66 are arranged in a line.

  In the current collector exposed region 76 of the electrode sheet 60, a punching line 78 as shown in FIG. By cutting along the punching line 78, the electrode sheet 60 in which one electrode tab 50 is provided for each unit electrode 62 on the side 72 along the longitudinal direction of the composite material layer region 74 can be produced. (FIG. 5B).

  Next, as shown in FIG. 5B, a cut for forming a cut 64 at a position where the virtual cutting line 66 intersects the side 70 and the side 72 along the longitudinal direction of the composite material layer region 74. Virtualize line 80. By cutting along the cut line 80, cuts 64 can be formed on the side 70 and the side 72 of the composite material layer region 74 (FIG. 5C). The formed cuts 64 are formed at both ends of the virtual cutting line 66 and are provided at intervals corresponding to the width of the unit electrode 62.

  The electrode sheet 60 in which the cuts 64 are formed is cut along a virtual cutting line 66 so that the cutout portions 20 shown in FIG. 2 are formed at the four corners of the rectangular sheet in FIG. The electrode 10 shown can be made. In addition, by appropriately changing the shape of the virtual cut line 80 when forming the cut 64, the electrode 10 in which the cutout portions 20 shown in FIG. 3 or FIG. 4 are formed at the four corners of the rectangular sheet is produced. be able to.

  In the production of the electrode 10, as a means used for cutting the composite material layer region 74 or the current collector exposed region 76 in the electrode sheet 60, a known cutting means can be used in electrode production, for example, a die press, a cutter, a laser Etc.

  The other example of manufacture of the electrode 10 of this embodiment is shown. In the electrode sheet 90 shown to Fig.6 (a), the compound material layer area | region 74 and the electrical power collector exposure area | region 76 are formed along with the longitudinal direction alternately. Both the mixture layer region 74 and the current collector exposed region 76 are formed over the entire width of the electrode sheet 60 in the short direction. The electrode sheet 90 has a configuration in which unit electrodes 62 divided by virtual cutting lines 66 are arranged in a line.

  The position of the virtual cutting line 66 in the electrode sheet 90 may be determined according to the shape of the electrode 10 to be produced, and is not particularly limited. As shown in FIG. 6, when the electrode sheet 90 has a structure for producing the electrode 10 in which the electrode tab 50 extends from only one side in the short direction, the virtual cutting line 66 is a mixture layer. It is preferably in the vicinity of the boundary line between the region 74 and the current collector exposed region 76. This is because a wide range of electrode mixture layers can be provided in the electrode 10 and less material is discarded.

  As shown in FIG. 6A, a cut line 80a for forming a cut 64a is formed at a position where the virtual cutting line 66 intersects with the side 68 and the side 70 along the longitudinal direction of the electrode sheet 90. Be virtual. In addition, a cut line 80b for forming the cut 64b is hypothesized at a vertex where the cut line 80a is not hypothesized among the vertices of the rectangular mixture layer region 74. By cutting along the cut lines 80a and 80b, cuts 64a and 64b can be formed on the side 68 and the side 70 of the electrode sheet 90 (FIG. 6B).

  By cutting the electrode sheet 90 in which the cuts 64 are formed along a virtual cutting line 66, a substantially rectangular unit electrode 62 having the structure shown in FIG. 6C can be produced. Next, in the unit electrode 62, a punching line 82 as shown in FIG. By cutting along the punching line 82, the electrode having the tab 20 at the four corners of the rectangular sheet and the electrode tab 50 extending from the end side 14 along the short direction of the electrode sheet 90 is provided. 10 can be manufactured (FIG. 6D).

  FIG. 7 shows an enlarged view of the vicinity of the notch 64 in the electrode sheet 60 shown in FIG. The shape of the notch 64 is formed so that the notch 20 appears in the electrode 10 by cutting the electrode sheet 60.

  The notch 64 preferably has a shape formed by joining the shape of the notch 20 specifically described above and a shape symmetrical to the notch 20 at a side corresponding to the extension line of the end side 11. By providing the electrode sheet 60 with the cut 64 having such a shape in advance, as shown in FIG. 1, there are notches 20 at both ends of the edge 12, and the number of places where the stress on the peripheral member can be buffered is increased. This is because the electrode 10 can be easily manufactured.

  Although the specific example of the shape of the notch 64 is described, the shape of the notch 64 is not limited to the following specific examples.

  The depth D1 of the cuts 64, that is, the maximum length along the cut line 66 of the cuts 64 can be, for example, 5% or more and 30% or less with respect to the width of the electrode sheet 60 in the short direction. Moreover, the depth D1 of the notch 64 can be 5 mm or more and 20 mm or less, for example. As an example, the depth D1 may be 5.6 mm.

  The width W1 of the cut 64, that is, the length at which the cut 64 is provided on the side 70 of the electrode sheet 60 is, for example, the length of the unit electrode 62 along the side 70 of the electrode sheet 60 (the length of the end 12 of the electrode 10). 2) or more and 20% or less. Moreover, the width W1 of the notch 64 can be 2 mm or more and 10 mm or less, for example. As an example, the length W1 may be 5.8 mm.

  As shown in FIG. 7, the notch 64 preferably has a straight portion 92 that is orthogonal to the cutting line 66 at the connection portion with the cutting line 66. Since the notch 64 has the straight portion 92, formation of sharp protrusions can be prevented even when the electrode sheet 60 is cut out of the cutting line 66 in the cutting process. The length W2 of the straight line portion 92 varies depending on the cutting margin in the cutting process, that is, the degree of deviation between the cutting line 66 and the actual cutting surface, but is 1.0 mm or more and 5.0 mm or less, for example. be able to. As an example, the length W2 may be 1.8 mm.

  As shown in FIG. 7, the notch 64 preferably has a rectangular region including the straight portion 92. In the rectangular region, the protruding portion 30 is formed in the manufactured electrode 10 by increasing the length D2 of the linear portion 96 orthogonal to the linear portion 92 with respect to the length W2 of the linear portion 92. The The length D2 of the straight line portion 96 can be, for example, 100% or more and 400% or less with respect to the length W2 of the straight line portion 92. Further, the length D2 of the linear portion 96 can be set to 1 mm or more and 20 mm or less. As an example, the length D2 may be 3.6 mm.

  Further, in a rectangular region, chamfering with a radius of curvature of about 0.2 mm may be performed at a corner portion that is an intersection of the straight portion 92 and the straight portion 96. Chamfering with a radius of curvature of about 0.2 mm may also be performed at a corner portion that is an intersection of the straight line portion 94 and the straight line portion 96. In particular, by performing chamfering at the intersection between the straight line portion 94 and the straight line portion 96, damage during contact with the peripheral member can be further buffered, and deterioration during charging and discharging as a power storage device can be suppressed. .

  The notch 64 is preferably formed so as to have a straight line portion 94 that becomes a straight line portion 44 having the second connection point 26 as one end portion in the cutout portion 20 of the electrode 10 to be manufactured. Since the notch 64 has the straight portion 94, even when the notch 64 is cut in the short direction of the electrode sheet 60 with respect to the design in the step of forming the notch 64, the straight portion 94 in the formed notch 64 is cut. This is because the angle formed between the electrode sheet 60 and the side 70 of the electrode sheet 60 is not changed, so that the accuracy of cutting in the process of forming the notch 64 can be remarkably improved, and the quality and reliability of the manufactured electrode 10 can be improved. . The straight part 94 is more preferable when the angle formed with the side 70 of the electrode sheet 60 is an angle of 100 ° to 160 °.

  In addition, although an example of the invention of the present disclosure has been described so far using the electrode 10, the positive electrode 110 and the negative electrode 120 facing each other in the electrode assembly 100 are the same as those in the negative electrode 120 in order to suppress deterioration of charge / discharge characteristics. The area of the surface facing the positive electrode 110 may be larger than the area of the surface facing the negative electrode 120 of the positive electrode 110. In this case, the notch 20 can be formed with the same size in both the positive electrode 110 and the negative electrode 120 even if the respective areas are different. Further, the notch 20 may have different dimensions between the positive electrode 110 and the negative electrode 120.

  The notches 64 in the electrode sheet 60 may be formed using a known means. For example, the electrode sheet 60 using a die press may be punched out, and the electrode sheet 60 is cut using a laser or the like. May be.

  The method for producing the electrode 10 of the present embodiment is not limited to the method using the electrode sheet 60 shown in FIG. 5 or the electrode sheet 90 shown in FIG. 6, and the order of cutting the electrode sheet 60 and the like is as described above. It is not limited. For example, in order to produce the electrode 10 of this embodiment, the electrode sheet 60 in which the unit electrodes 62 are arranged in two or more rows in parallel can also be used. In another example, the electrode 10 of the present embodiment is manufactured by cutting the electrode sheet 60 not provided with the notches 64 to produce the electrode 10 and then forming the cutout portion 20 by a known means. You can also Further, the structure of the electrode 10 of the present embodiment is not limited to the structure shown in FIG. 1 and FIG.

  It describes about the material etc. which comprise the electrode 10. FIG. The materials for the current collector and the electrode mixture layer may be selected depending on the power storage device to be manufactured. For example, when the power storage device is a lithium ion secondary battery, a metal foil such as aluminum, copper, stainless steel, or nickel, and a film in which the metal is disposed on a surface layer can be used as the current collector. For the positive electrode current collector, a metal that is stable in the potential range of the positive electrode such as aluminum is preferably used, and for the negative electrode current collector, a metal that is stable in the potential range of the negative electrode such as copper is preferably used.

  The electrode mixture layer preferably includes an electrode active material and further includes a binder. As the positive electrode active material, for example, a lithium-containing composite oxide is used. Examples of suitable lithium-containing composite oxides include nickel-cobalt-manganese and nickel-cobalt-aluminum lithium-containing composite oxides. The negative electrode active material is not particularly limited as long as it can reversibly occlude and release lithium ions. For example, carbon materials such as natural graphite and artificial graphite, metals such as Si and Sn, and metals that form an alloy with lithium, and Further, alloys of these metals and composite oxides can be used. In the electrode 10, the electrode mixture layer is preferably formed on both surfaces of the current collector.

  FIG. 8 shows an example of an electrode assembly 100 manufactured using the electrode 10 (at least one of the positive electrode 110 and the negative electrode 120) according to this embodiment. Electrode assembly 100 includes a positive electrode 110, a negative electrode 120, and a separator 130 disposed between positive electrode 110 and negative electrode 120. The number of positive electrodes 110 and negative electrodes 120 in the electrode assembly 100 is not particularly limited. The electrode 10 according to the present embodiment can be used as at least one of the positive electrode 110 and the negative electrode 120.

  In the electrode assembly 100, a positive electrode tab 112 is provided at one end of one side of a rectangular region where the positive electrode mixture layer is formed in the positive electrode 110, and a rectangular region where the negative electrode mixture layer is formed in the negative electrode 120. The negative electrode tab 122 is provided at an end portion of the side different from the end portion where the positive electrode tab 112 is provided.

  When the power storage device is a battery, the battery includes an exterior body and a power generation element accommodated in the exterior body. A suitable example of the battery is a lithium ion secondary battery. The power generation element includes, for example, the electrode assembly 100 and a nonaqueous electrolyte. Examples of the structure of the exterior body include an exterior body that has a bottomed rectangular tube shape and whose opening is sealed by a sealing plate.

  The battery manufacturing method according to the present embodiment will be described specifically by taking the case of using a bottomed rectangular tube-shaped exterior body as an example. The sealing plate has a positive terminal mounting hole and a negative terminal mounting hole. An insulating member and a positive electrode current collector are arranged around the positive electrode terminal mounting hole and inside the battery. Also, an insulating member is disposed around the positive terminal mounting hole and outside the battery. Then, a positive electrode terminal is inserted from the outside of the battery into the through holes provided in both the insulating member and the positive electrode current collector, and the tip of the positive electrode terminal is caulked and fixed to the positive electrode current collector. In addition, it is preferable to weld the crimping part of a positive electrode terminal to a positive electrode collector.

  An insulating member and a negative electrode current collector are disposed around the negative electrode terminal mounting hole and inside the battery. Also, an insulating member is disposed around the negative electrode terminal mounting hole and outside the battery. Then, the negative electrode terminal is inserted from the outside of the battery into the through holes provided in both the insulating member and the negative electrode current collector, and the tip of the negative electrode terminal is caulked and fixed to the negative electrode current collector. In addition, it is preferable to weld the caulking portion of the negative electrode terminal to the negative electrode current collector.

  The stacked positive electrode tab portions of the electrode assembly 100 are welded to the positive electrode current collector, and the stacked negative electrode tab portions of the electrode assembly 100 are welded to the negative electrode current collector. As the welding connection, resistance welding, laser welding, ultrasonic welding, or the like can be used.

  The electrode assembly 100 covered with the insulating sheet is inserted into a bottomed rectangular tube-shaped exterior body. Thereafter, the exterior body and the sealing plate are connected by welding to seal the opening of the exterior body. Thereafter, a nonaqueous electrolytic solution containing an electrolyte and a solvent is injected from an electrolytic solution injection hole provided on the sealing plate. Thereafter, the electrolyte injection hole is sealed with a sealing plug.

  The sealing plate is provided with a gas discharge valve that breaks when the internal pressure of the battery becomes a predetermined value or more and discharges the internal gas of the battery to the outside. Note that a current interruption mechanism can be provided in the conductive path between the positive electrode 110 and the positive electrode terminal or in the conductive path between the negative electrode 120 and the negative electrode terminal. The current interrupting mechanism is preferably one that operates when the internal pressure of the battery becomes a predetermined value or more and cuts the conductive path. Note that the operating pressure of the current interrupt mechanism is set lower than the operating pressure of the gas discharge valve.

  The structure of the exterior body in the case where the power storage device using the electrode 10 of the present embodiment is a battery is not limited to the above-mentioned bottomed rectangular tube-shaped exterior can, and is composed of, for example, a laminate film or the like. It may be.

  The power storage device in which the electrode 10 of the present embodiment is used is not limited to a lithium ion secondary battery, and includes, for example, secondary batteries other than lithium ion secondary batteries and capacitors such as electric double layer capacitors. To do. The power storage device according to the present embodiment includes a power storage device in which the power storage device electrode 10 of the present embodiment is included in at least one of a positive electrode and a negative electrode of a secondary battery, and a power storage device electrode 10 of the present embodiment. Examples include capacitors included in the polarizable electrode.

10 Electrode for power storage device (electrode) 11, 12, 13, 14 End side, 15, 16, 17, 18 Vertex, 20 Notch, 22 Notch side, 24 First connection point, 26 Second connection point, 28, 44, 46, 92, 94, 96 Straight part, 30 Raised part, 32, 34, 36, 38 Intersection, 40 section, 41 1st section, 42 2nd section, 50 electrode tab, 60, 90 electrode sheet, 62 Unit electrode, 64, 64a, 64b notch, 66 cutting line, 68, 70, 72 sides, 74 mixed material layer area, 76 current collector exposed area, 78, 82 punching line, 80, 80a, 80b notching line, 100 Electrode assembly, 110 positive electrode, 112 positive electrode tab, 120 negative electrode, 122 negative electrode tab, 130 separator.

Claims (9)

A rectangular sheet,
The rectangular sheet has a first end side and a second end side intersecting the first end side,
Notches are provided at least at the vertices of the first end side and the second end side,
The cutout portion is formed with a cutout side connected to each of the first end side and the second end side at the first connection point and the second connection point,
When the bisector of the inner angle at the first connection point is a straight line α, and the line perpendicular to the straight line α at the first connection point is a straight line β, the straight line β intersects the notch side, Forming a ridge surrounded by the straight line β and the cut-out side or by the straight line β, the cut-out side and the second end side;
The section included in the cutout side and serving as the outer edge of the raised portion has a curved line, or has a corner having an inner angle larger than the inner angle of the first connection point.
Electrode for power storage device.   The electrode for a power storage device according to claim 1, wherein an inner angle of the first connection point is 90 °.   The electrode for an electrical storage device according to claim 1 or 2, wherein all the inner angles of the corner portions are less than 180 °.   The power storage device according to any one of claims 1 to 3, wherein the section includes the corner portion, and the cut-out side includes a straight portion between a vertex of the corner portion and the second connection point. electrode.   The section has a curve, and the cut-out side has a straight line portion between an end portion close to the second connection point and both ends of the curve, and the second connection point. An electrode for a power storage device according to any one of the above.   The electrode for an electrical storage device according to any one of claims 1 to 5, wherein an electrode tab is provided on a fourth end side facing the second end side.   The shape of the notch provided at the apex of the first end side and the second end side at the apex of the third end side and the second end side facing the first end side The electrode for electrical storage apparatuses as described in any one of Claims 1-6 in which the 2nd notch part which has a line symmetrical shape is provided.   The power storage device according to claim 1, wherein an internal angle of the second connection point configured by the second end side and the cut-out side is larger than an internal angle of the first connection point. Electrode. The electrical storage apparatus in which the electrode for electrical storage apparatuses as described in any one of Claims 1-8 is contained in at least one among a positive electrode and a negative electrode.

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