Battery cell and electrode

Abstract

To suppress the damage of an element of a battery cell, such as an electrode, a separator, or an exterior material.SOLUTION: A positive electrode 100 includes a positive electrode current collector 110 having a pair of a first side 110a and a second side 110b, which face each other, and another pair of a third side 110c and a fourth side 110d, which face each other, and a positive electrode tab 112 extracted from the fourth side 110d of the positive electrode current collector 110. A first notch 114a is provided in at least one corner part between the pair of the first side 110a and the second side 110b and another pair of the third side 110c and the fourth side 110d of the positive electrode current collector 110. The first notch 114a and the first side 110a form a corner part that is substantially right angled.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a battery cell and an electrode. [Background technology]

[0002] In recent years, various types of battery cells have been developed. Each battery cell includes electrodes including a positive electrode and a negative electrode.

[0003] Patent Documents 1 and 2 describe battery cells in which the corners of the electrodes are cut out.

[0004] Patent Document 3 describes a battery cell in which the corners of the electrodes are chamfered.

[0005] Patent Document 4 describes a battery cell, in which the corners of the electrodes have arc-shaped contours. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2-56856 [Patent Document 2] Japanese Patent Application Publication No. 10-270014 [Patent Document 3] International Publication No. 2013 / 031938 [Patent Document 4] Japanese Patent Application Laid-Open No. 2001-160397 Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, the trend toward higher energy density has led to the development of thicker battery cells. In the case of thicker cells, interference between the electrode corners and the exterior material becomes more pronounced, which can damage battery cell elements such as the electrodes, separators, and exterior material.

[0008] One example of an object of the present invention is to suppress damage to battery cell elements such as electrodes, separators, exterior materials, etc. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0009] One aspect of the present invention is as follows. 1. An electrode including a current collector including a pair of opposing sides and another pair of opposing sides, and a tab drawn out from one of the other pair of sides of the current collector; a notch is provided in at least one corner portion between the pair of sides and the other pair of sides of the current collector, The at least one notch and at least one of the pair of sides form a substantially right-angled corner of the battery cell. 2. The electrode further includes an insulating material covering the pair of sides and another corner between the other pair of sides of the current collector, 1. The battery cell according to 1, wherein the notch is not provided in the other corners. 3. The electrodes include a positive electrode and a negative electrode; 3. The battery cell according to claim 1, wherein the notch is provided at the corners of the positive electrode and the negative electrode that are located on the same side with respect to the center of the positive electrode or the negative electrode. 4. A current collector having a pair of sides facing each other and another pair of sides facing each other; a tab drawn out from one of the other pair of sides of the current collector; Equipped with a notch is provided in at least one corner portion between the pair of sides and the other pair of sides of the current collector, The at least one notch and at least one of the pair of sides form a substantially right-angled corner. [Effects of the Invention]

[0010] According to the above-described aspects of the present invention, damage to battery cell elements such as electrodes, separators, and exterior materials can be suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a plan view of a battery cell according to the embodiment. [Figure 2] FIG. 2 is a diagram showing a part of the cross section AA of FIG. [Figure 3] 4 is an enlarged plan view of a first notch of a positive electrode current collector according to an embodiment and a third notch of a negative electrode current collector according to an embodiment. FIG. [Figure 4] 3A to 3C are diagrams illustrating a method for manufacturing a positive electrode according to an embodiment. [Figure 5] 10A and 10B are diagrams for explaining the relationship between notches and cut lines according to the embodiment. [Figure 6] 10A and 10B are diagrams for explaining the relationship between notches and cut lines in a comparative example. [Figure 7] FIG. 6 is a diagram showing a modification of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and descriptions thereof will be omitted as appropriate.

[0013] Fig. 1 is a plan view of a battery cell 10 according to an embodiment of the present invention, and Fig. 2 is a view showing a portion of the cross section taken along line AA in Fig. 1.

[0014] For the purpose of explanation, the X, Y, and Z directions are shown in each figure. The X direction is parallel to the longitudinal direction of the battery cell 10. The Y direction is perpendicular to the X direction. The Y direction is parallel to the lateral direction of the battery cell 10. The Z direction is perpendicular to both the X and Y directions. The Z direction is parallel to the height direction of the battery cell 10. However, the relationship between the X, Y, Z directions, longitudinal direction, lateral direction, and height direction of the battery cell 10 is not limited to this example. In FIG. 1, a white circle with a black dot indicating the Z direction indicates that the arrow indicating the Z direction is pointing from the back of the page to the front. In FIG. 2, a white circle with an X indicating the Y direction indicates that the arrow indicating the Y direction is pointing from the front of the page to the back.

[0015] Hereinafter, as needed, the side indicated by the arrow indicating the X direction will be referred to as the +X side, and the side opposite the side indicated by the arrow indicating the X direction will be referred to as the -X side. Hereinafter, as needed, the side indicated by the arrow indicating the Y direction will be referred to as the +Y side, and the side opposite the side indicated by the arrow indicating the Y direction will be referred to as the -Y side. Hereinafter, as needed, the side indicated by the arrow indicating the Z direction will be referred to as the +Z side, and the side opposite the side indicated by the arrow indicating the Z direction will be referred to as the -Z side.

[0016] As shown in FIGS. 1 and 2, a battery cell 10 includes a positive electrode 100, a negative electrode 200, a separator 300, an exterior material 400, a positive electrode lead 510, and a negative electrode lead 520. As shown in FIG. 2, the positive electrode 100 includes a positive electrode current collector 110, a positive electrode tab 112, two layers of positive electrode active material 120, and two layers of insulating material 130. As shown in FIG. 2, the negative electrode 200 includes a negative electrode current collector 210, a negative electrode tab 212, and two layers of negative electrode active material 220. In this embodiment, a plurality of positive electrodes 100 and a plurality of negative electrodes 200 are alternately stacked in the Z direction. As shown in FIG. 2, a separator 300 is located between the positive electrodes 100 and the negative electrodes 200 adjacent to each other in the Z direction.

[0017] The positive electrode current collector 110 is, for example, a metal foil containing at least one of aluminum and an aluminum alloy. The positive electrode current collector 110 has a generally sheet-like shape that is generally perpendicular to the Z direction. As shown in FIG. 1, the positive electrode current collector 110 has a generally rectangular shape having a first side 110a, a second side 110b, a third side 110c, and a fourth side 110d. The first side 110a and the second side 110b face each other in the Y direction and extend in the X direction. The third side 110c and the fourth side 110d face each other in the X direction and extend in the Y direction. When viewed from the Z direction, the first side 110a, the second side 110b, the third side 110c, and the fourth side 110d are located on the +Y side, the -Y side, the +X side, and the -X side, respectively, of the center of the positive electrode current collector 110. As shown in FIG. 1, a positive electrode tab 112 is drawn out from the fourth side 110d. The positive electrode current collector 110 and the positive electrode tab 112 are integral with each other.

[0018] As shown in Fig. 2, two layers of positive electrode active material 120 are located on both sides in the Z direction of the positive electrode current collector 110. Each positive electrode active material 120 contains, for example, a lithium transition metal oxide. As shown in Figs. 1 and 2, both sides in the Z direction of the positive electrode tab 112 are not covered with the positive electrode active material 120.

[0019] The negative electrode current collector 210 is, for example, a metal foil containing at least one of copper and a copper alloy. The negative electrode current collector 210 has a generally sheet-like shape that is generally perpendicular to the Z direction. As shown in FIG. 1, the negative electrode current collector 210 has a generally rectangular shape having a fifth side 210a, a sixth side 210b, a seventh side 210c, and an eighth side 210d. The fifth side 210a and the sixth side 210b face each other in the Y direction and extend in the X direction. The seventh side 210c and the eighth side 210d face each other in the X direction and extend in the Y direction. When viewed from the Z direction, the fifth side 210a, the sixth side 210b, the seventh side 210c, and the eighth side 210d are located on the +Y side, the -Y side, the +X side, and the -X side, respectively, of the center of the negative electrode current collector 210. As shown in FIG. 1, the negative electrode tab 212 is drawn out from the seventh side 210c. The negative electrode current collector 210 and the negative electrode tab 212 are integral with each other.

[0020] 2, two layers of anode active material 220 are located on both sides in the Z direction of the anode current collector 210. Each anode active material 220 contains, for example, a carbon material or a silicon material. As shown in FIGS. 1 and 2, both sides of the anode tab 212 in the Z direction are not covered with the anode active material 220.

[0021] The separator 300 contains, for example, a resin. The separator 300 has a generally sheet-like shape that is generally perpendicular to the Z direction. In this embodiment, each of the multiple separators 300 is located between a positive electrode 100 and a negative electrode 200 that are adjacent to each other in the Z direction. However, the shape of the separator 300 is not limited to this example. For example, when viewed from the X direction, the separator 300 may have a zigzag shape that covers one end of the positive electrode 100 on the +Y side and the −Y side and covers the other end of the negative electrode 200 on the +Y side and the −Y side.

[0022] As shown in FIG. 2, two layers of insulating material 130 are located on both sides of the positive electrode current collector 110 in the Z direction. Each insulating material 130 contains, for example, insulating particles or resin. Each insulating material 130 is located on the −X side relative to the −X side end of each positive electrode active material 120. The −X side end of each positive electrode active material 120 and the +X side end of each insulating material 130 are in contact with each other. As shown in FIGS. 1 and 2, each insulating material 130 and the −X side end of the negative electrode 200 at least partially overlap in the Z direction. Therefore, the insulating material 130 can prevent contact and short-circuiting between the positive electrode current collector 110 and the negative electrode current collector 210.

[0023] The exterior material 400 is, for example, a laminate film. The exterior material 400 includes, for example, aluminum foil and a resin film. The exterior material 400 forms a storage space that contains a laminate including a plurality of positive electrodes 100, a plurality of negative electrodes 200, and a plurality of separators 300 stacked in the Z direction, and an electrolyte solution not shown in FIGS. 1 and 2. The shape of the exterior material 400 is not particularly limited. For example, the exterior material 400 may include one exterior material that defines a recess that forms a portion on the -Z side of the storage space, and another exterior material that defines a recess that forms a portion on the +Z side of the storage space.

[0024] The -X side end of the positive electrode lead 510 is drawn out from the -X side end of the exterior material 400. The +X side end of the positive electrode lead 510 and the -X side end of the positive electrode tab 112 are joined to each other and electrically connected to each other. The +X side end of the negative electrode lead 520 is drawn out from the +X side end of the exterior material 400. The -X side end of the negative electrode lead 520 and the +X side end of the negative electrode tab 212 are joined to each other and electrically connected to each other.

[0025] In the embodiment, the battery cell 10 is a battery cell containing an electrolyte solution. However, the battery cell 10 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to the separator 300. An all-solid-state battery does not contain an electrolyte solution. Hereinafter, unless otherwise specified, the battery cell 10 will be described as a battery cell containing an electrolyte solution.

[0026] 1, when viewed from the Z direction, the fifth side 210a, the sixth side 210b, and the seventh side 210c of the negative electrode current collector 210 are located outside the first side 110a, the second side 110b, and the third side 110c of the positive electrode current collector 110 with respect to the center of the positive electrode current collector 110 or the negative electrode current collector 210, respectively. As shown in FIG. 1, when viewed from the Z direction, the fourth side 110d of the positive electrode current collector 110 is located outside the eighth side 210d of the negative electrode current collector 210 with respect to the center of the positive electrode current collector 110 or the negative electrode current collector 210. Even if the negative electrode 200 expands due to charging of the battery cell 10 and the eighth edge 210d of the negative electrode current collector 210 moves toward the −X side, the eighth edge 210d of the negative electrode current collector 210 can be prevented from protruding outward from the fourth edge 110d of the positive electrode current collector 110 with respect to the center of the positive electrode current collector 110 or the negative electrode current collector 210. Therefore, a short circuit between the positive electrode tab 112 and the negative electrode current collector 210 can be suppressed compared to when the eighth edge 210d of the negative electrode current collector 210 protrudes outward from the fourth edge 110d of the positive electrode current collector 110 with respect to the center of the positive electrode current collector 110 or the negative electrode current collector 210.

[0027] 1, a first notch 114a is provided in a corner between the first side 110a and the third side 110c of the positive electrode current collector 110. Therefore, compared to a case where the first notch 114a is not provided, interference between the corner between the first side 110a and the third side 110c of the positive electrode current collector 110 and the periphery of the corner of the exterior material 400 can be suppressed.

[0028] 1, a second notch 114b is provided at the corner between the second side 110b and the third side 110c of the positive electrode current collector 110. Therefore, compared to a case where the second notch 114b is not provided, interference between the corner between the second side 110b and the third side 110c of the positive electrode current collector 110 and the periphery of the corner of the exterior material 400 can be suppressed.

[0029] As shown in FIG. 1, no notch is provided at the corner between the first side 110a and the fourth side 110d of the positive electrode current collector 110. Therefore, the corner between the first side 110a and the fourth side 110d of the positive electrode current collector 110 forms a substantially right angle. As shown in FIG. 1, the corner between the first side 110a and the fourth side 110d of the positive electrode current collector 110 is covered with an insulating material 130. Furthermore, as shown in FIG. 2, the thickness of each insulating material 130 in the Z direction is thinner than the thickness of each positive electrode active material 120 in the Z direction. Therefore, even if no notch is provided at the corner between the first side 110a and the fourth side 110d of the positive electrode current collector 110, interference between the corner between the first side 110a and the fourth side 110d of the positive electrode current collector 110 and the periphery of the corner of the exterior material 400 can be suppressed. Furthermore, since no notch is provided at the corner between the first side 110a and the fourth side 110d of the positive electrode current collector 110, the capacity of the positive electrode 100 can be increased.

[0030] As shown in FIG. 1, no notch is provided at the corner between the second side 110b and the fourth side 110d of the positive electrode current collector 110. Therefore, the corner between the second side 110b and the fourth side 110d of the positive electrode current collector 110 forms a substantially right angle. As shown in FIG. 1, the corner between the second side 110b and the fourth side 110d of the positive electrode current collector 110 is covered with an insulating material 130. Furthermore, as shown in FIG. 2, the thickness of each insulating material 130 in the Z direction is thinner than the thickness of each positive electrode active material 120 in the Z direction. Therefore, even if no notch is provided at the corner between the second side 110b and the fourth side 110d of the positive electrode current collector 110, interference between the corner between the second side 110b and the fourth side 110d of the positive electrode current collector 110 and the periphery of the corner of the exterior material 400 can be suppressed. Furthermore, since no notch is provided at the corner between the second side 110b and the fourth side 110d of the positive electrode current collector 110, the capacity of the positive electrode 100 can be increased.

[0031] In the embodiment, when viewed from the Z direction, the center of the positive electrode current collector 110 may be offset toward the +X side with respect to the center of the storage space formed by the exterior material 400. By offsetting the center of the positive electrode current collector 110 toward the +X side with respect to the center of the storage space formed by the exterior material 400, the fourth edge 110d can be spaced apart from the end of the storage space on the -X side formed by the exterior material 400. This makes it possible to more easily suppress interference between the two corners on the -X side of the positive electrode current collector 110 and the peripheries of these two corners of the exterior material 400.

[0032] 1, a third notch 214a is provided in a corner between the fifth side 210a and the seventh side 210c of the negative electrode current collector 210. Therefore, compared to when the third notch 214a is not provided, interference between the corner between the fifth side 210a and the seventh side 210c of the negative electrode current collector 210 and the periphery of the corner of the exterior material 400 can be suppressed. Furthermore, in the example shown in FIG. 1, the first notch 114a and the third notch 214a are provided in corners of the positive electrode current collector 110 and the negative electrode current collector 210 on the same side, that is, on the +X side and the +Y side with respect to the center of the positive electrode current collector 110 or the negative electrode current collector 210, when viewed from the Z direction. Therefore, compared to when only one of the first notch 114a and the third notch 214a is provided, the shapes of the positive electrode current collector 110 and the negative electrode current collector 210 can be made similar, and damage to elements of the battery cell 10 such as the positive electrode 100, the negative electrode 200, the separator 300, and the exterior material 400 can be suppressed.

[0033] 1, a fourth notch 214b is provided in a corner between the sixth side 210b and the seventh side 210c of the negative electrode current collector 210. Therefore, compared to a case where the fourth notch 214b is not provided, interference between the corner between the sixth side 210b and the seventh side 210c of the negative electrode current collector 210 and the periphery of the corner of the exterior material 400 can be suppressed. Furthermore, in the example shown in FIG. 1, the second notch 114b and the fourth notch 214b are provided in corners of the positive electrode current collector 110 and the negative electrode current collector 210 on the same side, that is, on the +X side and the −Y side with respect to the center of the positive electrode current collector 110 or the negative electrode current collector 210, when viewed from the Z direction. Therefore, compared to when only one of the second notch 114b and the fourth notch 214b is provided, the shapes of the positive electrode current collector 110 and the negative electrode current collector 210 can be made similar, and damage to elements of the battery cell 10 such as the positive electrode 100, the negative electrode 200, the separator 300, and the exterior material 400 can be suppressed.

[0034] As shown in FIG. 1 , no notch is provided at the corner between the fifth side 210a and the eighth side 210d of the negative electrode current collector 210. Therefore, the corner between the fifth side 210a and the eighth side 210d of the negative electrode current collector 210 forms a substantially right angle. As shown in FIG. 1 , when viewed from the Z direction, the eighth side 210d of the negative electrode current collector 210 is located more inward than the fourth side 110d of the positive electrode current collector 110 with respect to the center of the positive electrode current collector 110 or the negative electrode current collector 210. Therefore, even if no notch is provided at the corner between the fifth side 210a and the eighth side 210d of the negative electrode current collector 210, interference between the corner between the fifth side 210a and the eighth side 210d of the negative electrode current collector 210 and the periphery of the corner of the exterior material 400 can be suppressed.

[0035] As shown in FIG. 1 , no notch is provided at the corner between the sixth side 210b and the eighth side 210d of the negative electrode current collector 210. Therefore, the corner between the sixth side 210b and the eighth side 210d of the negative electrode current collector 210 forms a substantially right angle. As shown in FIG. 1 , when viewed from the Z direction, the eighth side 210d of the negative electrode current collector 210 is located more inward than the fourth side 110d of the positive electrode current collector 110 with respect to the center of the positive electrode current collector 110 or the negative electrode current collector 210. Therefore, even if no notch is provided at the corner between the sixth side 210b and the eighth side 210d of the negative electrode current collector 210, interference between the corner between the sixth side 210b and the eighth side 210d of the negative electrode current collector 210 and the periphery of the corner of the exterior material 400 can be suppressed.

[0036] The number and positions of the notches provided at the corners of each electrode are not limited to the example shown in FIG. 1 . For example, the positive electrode current collector 110 may be provided with only one of the first notch 114a and the second notch 114b. A notch may also be provided in at least one of the two corners on the −X side of the positive electrode current collector 110. The negative electrode current collector 210 may be provided with only one of the third notch 214a and the fourth notch 214b. A notch may also be provided in at least one of the two corners on the −X side of the negative electrode current collector 210. A notch may also be provided in only one of the positive electrode current collector 110 and the negative electrode current collector 210.

[0037] FIG. 3 is an enlarged plan view of the first notch 114a of the positive electrode current collector 110 according to the embodiment and the third notch 214a of the negative electrode current collector 210 according to the embodiment.

[0038] 3, the first notch 114a includes a first notch side 114a1 and a second notch side 114a2. The first notch side 114a1 and the third side 110c intersect obliquely with each other, with an obtuse-angled corner formed between the +X side end of the first notch side 114a1 and the +Y side end of the third side 110c. The second notch side 114a2 and the first side 110a intersect approximately perpendicularly with each other, with an obtuse-angled corner formed between the +Y side end of the second notch side 114a2 and the +X side end of the first side 110a.

[0039] 3, the third notch 214a includes a third notch side 214a1 and a fourth notch side 214a2. The third notch side 214a1 and the seventh side 210c intersect obliquely with each other, with an obtuse-angled corner formed between the +X side end of the third notch side 214a1 and the +Y side end of the seventh side 210c. The fourth notch side 214a2 and the fifth side 210a intersect approximately perpendicularly with each other, with an obtuse-angled corner formed between the +Y side end of the fourth notch side 214a2 and the +X side end of the fifth side 210a.

[0040] In the embodiment, the shape of the second notch 114b is approximately symmetrical to the shape of the first notch 114a when viewed from the Z direction. In the embodiment, the shape of the fourth notch 214b is approximately symmetrical to the shape of the third notch 214a when viewed from the Z direction.

[0041] Fig. 4 is a diagram illustrating a method for manufacturing the positive electrode 100 according to the embodiment. Fig. 5 is a diagram illustrating the relationship between the notch 114 and the cutoff line L according to the embodiment. Fig. 6 is a diagram illustrating the relationship between the notch 114 and the cutoff line L in a comparative example. The matters described for the method for manufacturing the positive electrode 100 using Figs. 4 and 5 can also be applied to the method for manufacturing the negative electrode 200.

[0042] In the example shown in FIG. 4, multiple positive electrodes 100 are cut out from a positive electrode sheet 100A. As shown in FIG. 4, the positive electrode sheet 100A includes a positive electrode current collector sheet 110A, multiple positive electrode tabs 112, positive electrode active material 120, and insulating material 130. As shown in FIG. 4, the multiple positive electrode tabs 112 are pulled out from the −X side edge of the positive electrode current collector sheet 110A and are arranged at approximately equal intervals in the Y direction. As in the example shown in FIG. 2, the positive electrode active material 120 is located on both sides of the positive electrode current collector sheet 110A in the Z direction. As shown in FIG. 4, the insulating material 130 is located at the end of the −X side of the positive electrode current collector sheet 110A. As in the example shown in FIG. 2, the insulating material 130 is located on both sides of the positive electrode current collector sheet 110A in the Z direction. As shown in FIG. 4, multiple notches 114 are provided on the +X side edge of the positive electrode current collector sheet 110A. As shown in Fig. 4, the multiple notches 114 are arranged at approximately equal intervals in the Y direction. As shown in Fig. 5, when viewed from the Z direction, the notches 114 have an approximately isosceles trapezoidal shape with a pair of bases that are approximately parallel to the Y direction. The width of the notches 114 in the Y direction narrows toward the -X side. Each notch 114 is formed by, for example, punching.

[0043] In the example shown in FIG. 4, first, a portion of the rolled positive electrode sheet 100A is pulled out toward the -Y side. Next, the pulled-out portion of the positive electrode sheet 100A is cut out along the cutout line L. The cutout line L extends in the X direction and passes through the notch 114. By cutting out the positive electrode 100 along the cutout line L, a portion of the notch 114 at a corner on the +X side and +Y side of the positive electrode 100 located on the -Y side of the cutout line L becomes a first notch 114a, and another portion of the notch 114 at a corner on the +X side and -Y side of the positive electrode 100 located on the +Y side of the cutout line L becomes a second notch 114b. 3 and 4, the -Y side edge of the notch 114 is the first notch edge 114a1, a portion of the -X side edge of the notch 114 is the second notch edge 114a2, and the portion of the positive electrode sheet 100A through which the cut line L passes is the first edge 110a. As shown in FIG. 5, the -X side edge of the notch 114 is a substantially straight line that is substantially parallel to the Y direction. Therefore, as shown in FIG. 3, the second notch edge 114a2 and the first edge 110a form a substantially right-angled corner.

[0044] The perforation line L is designed to pass through approximately the center of the notch 114 in the Y direction, as in the first perforation line L1 shown in Fig. 5. However, in reality, the perforation line L may pass through a portion of the notch 114 that is shifted in the Y direction from approximately the center of the Y direction, as in the second perforation line L2 shown in Fig. 5. In the example shown in Fig. 5, the second perforation line L2 is shifted toward the +Y side with respect to the first perforation line L1. However, the second perforation line L2 may also be shifted toward the -Y side with respect to the first perforation line L1.

[0045] The comparative example shown in Fig. 6 is similar to the example shown in Fig. 5 except that, when viewed from the Z direction, the notch 114 has a substantially isosceles triangular shape with a base substantially parallel to the Y direction. The width of the notch 114 in the Y direction according to the comparative example narrows toward the -X side. In the comparative example shown in Fig. 6, the cut line L is also designed to pass through substantially the center of the notch 114 in the Y direction, as with the first cut line L1 shown in Fig. 6. However, in reality, the cut line L may pass through a portion of the notch 114 that is shifted in the Y direction from substantially the center in the Y direction, as with the second cut line L2 shown in Fig. 6.

[0046] In the comparative example shown in FIG. 6 , when the positive electrode sheet 100A is cut along the second cut line L2, an acute-angled edge is formed between the +Y side of the notch 114 and the side formed along the second cut line L2 in the positive electrode 100 located on the −Y side of the second cut line L2. However, when an acute-angled edge is formed in the positive electrode 100, it may be difficult to prevent damage to the components of the battery cell 10, such as the positive electrode 100, the negative electrode 200, the separator 300, and the exterior material 400. In contrast, in the embodiment shown in FIG. 5 , even when the positive electrode sheet 100A is cut along the second cut line L2, no edge corresponding to the acute-angled edge in the comparative example shown in FIG. 6 is formed in either the positive electrode 100 located on the +Y side of the second cut line L2 or the positive electrode 100 located on the −Y side of the second cut line L2. Therefore, in the embodiment shown in FIG. 5, damage to the elements of the battery cell 10, such as the positive electrode 100, negative electrode 200, separator 300, and exterior material 400, can be suppressed compared to the comparative example shown in FIG.

[0047] FIG. 7 is a diagram showing a modification of FIG.

[0048] As shown in Fig. 7, the notch 114 does not have to be a substantially isosceles trapezoid when viewed from the Z direction. In the example shown in Fig. 7, both sides of the notch 114 in the X direction are curved toward the center of the notch 114 in the X direction when viewed from the Z direction.

[0049] 7, the −X side of the notch 114 also has a substantially linear shape that is substantially parallel to the Y direction. Therefore, even when the positive electrode sheet 100A is cut along the second cut line L2, no edge corresponding to the acute-angled edge in the comparative example shown in FIG. 6 is formed in either the positive electrode 100 located on the +Y side of the second cut line L2 or the positive electrode 100 located on the −Y side of the second cut line L2. Therefore, in the modified example shown in FIG. 7, damage to elements of the battery cell 10, such as the positive electrode 100, negative electrode 200, separator 300, and exterior material 400, can be reduced compared to the comparative example shown in FIG. 6.

[0050] The shape of the notch 114 is not limited to the shapes shown in FIGS. 5 and 7. The -X side edge of the notch 114 is not particularly limited as long as the -X side edge of the notch 114 and the cutting line L form a substantially right-angled corner. The term "substantially right angle" does not necessarily mean a strict right angle, but may also deviate from a strict right angle as long as the intended purpose is achieved by the right angle. FIGS. 5 and 7 have been used to describe the notch in the positive electrode 100. However, the matters described regarding the notch in the positive electrode 100 using FIGS. 5 and 7 can also be applied to the notch in the negative electrode 200.

[0051] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted. [Explanation of symbols]

[0052] 10 Battery cell, 100 Positive electrode, 100A Positive electrode sheet, 110 Positive electrode current collector, 110A Positive electrode current collector sheet, 110a First side, 110b Second side, 110c Third side, 110d Fourth side, 112 Positive electrode tab, 114 Notch, 114a First notch, 114a1 First notch side, 114a2 Second notch side, 114b Second notch, 120 Positive electrode active material, 130 Insulating material, 200 Negative electrode, 210 Negative electrode current collector, 210a Fifth side, 210b Sixth side, 210c Seventh side, 210d Eighth side, 212 Negative electrode tab, 214a Third notch, 214a1 Third notch side, 214a2 Fourth notch edge, 214b fourth notch, 220 negative electrode active material, 300 separator, 400 exterior material, 510 positive electrode lead, 520 negative electrode lead, L cutting line, L1 first cutting line, L2 second cutting line

Claims

1. an electrode including a current collector including a pair of sides facing each other and another pair of sides facing each other, and a tab drawn out from one of the other pair of sides of the current collector; a notch is provided in at least one corner portion between the pair of sides and the other pair of sides of the current collector, The at least one notch and at least one of the pair of sides form a substantially right-angled corner.

2. the electrode further includes an insulating material covering the pair of sides and another corner between the other pair of sides of the current collector, The battery cell according to claim 1 , wherein the notch is not provided in the other corner portion.

3. The electrodes include a positive electrode and a negative electrode, The battery cell according to claim 1 , wherein the notch is provided at the corners of the positive electrode and the negative electrode that are located on the same side with respect to the center of the positive electrode or the negative electrode.

4. a current collector having a pair of sides facing each other and another pair of sides facing each other; a tab drawn out from one of the other pair of sides of the current collector; Equipped with a notch is provided in at least one corner portion between the pair of sides and the other pair of sides of the current collector, The at least one notch and at least one of the pair of sides form a substantially right-angled corner.

Images