Energy storage cell

Abstract

An energy storage cell comprises: an electrode body in which a foil element is wound to surround a winding axis; and a housing in which the electrode body is accommodated, wherein: the foil element comprises an electrode foil and a separator; the electrode foil comprises a current collector plate and an electrode composite material layer produced on the current collector plate; the electrode foil comprises a slot section extending in the direction of the winding axis in which the electrode composite material layer is not produced; a plurality of slot sections are produced in a direction in which the electrode foil extends; and a distance between the slot sections on an inside of the winding is smaller than a distance between the slot sections on an outside of the winding.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to an energy storage cell. 2. Description of related technology

[0002] Japanese patent application JP 2001-6749A discloses a lithium secondary battery with a wound internal electrode body in which a cathode metal foil body and an anode metal foil body are configured with a separator between them. The internal electrode body is manufactured such that a cathode foil, a separator, and an anode foil are wound together. SUMMARY OF THE INVENTION

[0003] The electrode body of the lithium secondary battery, configured as described above, is manufactured such that each foil is wound.

[0004] For example, the winding radius on the central winding side of the electrode body is small. Therefore, the winding radius of a cathode composite material layer of a cathode foil is also small on the central winding side, and consequently, the cathode composite material layer peels off or develops a crack. The same problem occurs with an anode composite material layer of an anode foil.

[0005] The present invention was made with regard to the above problem, and the object of the present invention is to provide a power storage cell that prevents the generation of a crack or the like in an electrode composite material layer. [1] A power storage cell comprising: an electrode body in which a foil element is wound in such a way that it surrounds a winding axis; and a housing in which the electrode body is housed, wherein: the foil element comprises an electrode foil and a separator; the electrode foil comprises a current collector plate and an electrode composite material layer produced on the current collector plate; the electrode foil includes a groove section extending in the direction of the winding axis in which the electrode composite material layer is not produced; a large number of groove sections are produced in one direction in which the electrode foil extends; and a distance between the slot sections on the inside of a winding is smaller than a distance between the slot sections on the outside of a winding. [2] The energy storage cell according to [1], wherein: the electrode body comprises a start-end section of a wound body of the electrode body and an end-end section of the wound body of the electrode body; and The distances between the groove sections increase from the beginning-end section to the end-end section. [3] The energy storage cell according to [1] or [2], wherein a slot width of the slot sections on the inside of the winding is smaller than a slot width of the slot section on the outside of the winding. [4] The energy storage cell according to one of [1] to [3], wherein: The electrode foil comprises a cathode foil and an anode foil; the cathode foil comprises a cathode current collector plate and a cathode composite material layer produced on the cathode current collector plate; the cathode foil includes a cathode groove section extending in the direction of the winding axis, in which the cathode composite material layer is not manufactured; the anode foil comprises an anode current collector plate and an anode composite material layer produced on the anode current collector plate; the anode foil includes an anode groove section extending in the direction of the winding axis in which the anode composite material layer is not manufactured; and The cathode slot section and the anode slot section are manufactured in such a way that they face each other. [5] The energy storage cell according to [4], wherein a slot width of the anode slot section is smaller than a slot width of the opposite cathode slot section.

[0006] With the energy storage cell of the present invention, it is possible to prevent the formation of a crack or the like in an electrode composite material layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The features and advantages as well as the technical and economic significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same reference numerals denote the same elements, showing: Fig. 1 a sectional view showing a power storage cell 1 according to an embodiment; Fig. 2 a perspective view that schematically shows an electrode body 10; Fig. 3 a top view showing a cathode foil 22; Fig. 4 a top view showing an anode foil 24; Fig. 5 an extended top view showing a state in which a foil element 20 is extended and in which foils are arranged; and Fig. Figure 6 shows a sectional view showing the cathode foil 22, the anode foil 24, a separator 21 and a separator 23. Fig. 5 shows. DETAILED DESCRIPTION OF EXECUTION FORMS

[0008] One embodiment of the present invention is described in detail below with reference to the drawings. In the drawings, identical or corresponding sections are identified by identical reference numerals, and descriptions thereof are not repeated.

[0009] Fig. Figure 1 is a sectional view showing a power storage cell 1 according to the embodiment. The power storage cell 1 comprises a cylindrical electrode body 10, which is manufactured to surround a winding axis O, a housing 11, a cathode current collector element 12, an anode current collector element 13, insulating elements 14, 15 and a cathode terminal 16.

[0010] In Fig. 1 and others, “Z” denotes a direction in which the winding axis O extends. “Z1” denotes one direction of the Z-direction. “Z2” denotes the other direction of the Z-direction. “R” denotes a radial direction of the electrode body 10.

[0011] The housing 11 comprises an upper plate 17, a lower plate 18, and a circumferential wall 19. The housing 11 is made of a metal material. The upper plate 17 is positioned at one end of the housing 11, and the lower plate 18 is positioned at the other end of the housing 11. The circumferential wall 19 is arranged between the upper plate 17 and the lower plate 18.

[0012] A through-hole 7 is formed in the upper plate 17. The insulating element 14 is arranged on an outer surface of the upper plate 17, and a through-hole is formed in the insulating element 14.

[0013] The insulating element 15 comprises an upper plate part 2 and a circumferential wall 3, which is provided on an outer circumferential edge of the upper plate part 2. The upper plate part 2 is arranged on an inner surface of the upper plate 17. The circumferential wall 3 is arranged on an inner circumferential surface of the circumferential wall 19. A through-hole is formed in the upper plate 17.

[0014] The cathode terminal 16 comprises a flat plate 50 and a shaft 51. The flat plate 50 is arranged on the insulating element 14. The shaft 51 is connected to the flat plate 50 and is manufactured to extend in the Z2 direction. The shaft 51 is inserted into the housing 11 through the through-hole 7 formed in the insulating element 14 and a through-hole formed in the insulating element 15.

[0015] The cathode current collector element 12 is arranged on a Z2-direction side of the insulating element 15. The cathode current collector element 12 has a plate shape, and a lower end section of the shaft 51 is welded to an upper surface of the cathode current collector element 12. For example, the cathode current collector element 12 is made of aluminum or a similar material.

[0016] The anode current collector element 13 is arranged on an inner surface of the lower plate 18. The anode current collector element 13 has a plate shape and is made of a metallic material such as copper.

[0017] The electrode body 10 is arranged between the cathode current collector element 12 and the anode current collector element 13 in the housing 11.

[0018] The electrode body 10 comprises a first end section 5, which is positioned on a Z1 direction side, and the cathode current collector element 12 is arranged on the first end section 5. The electrode body 10 comprises a second end section 6, which is positioned on a Z2 direction side, and the anode current collector element 13 is arranged on the second end section 6. The electrode body 10 has a hollow shape and a hollow section 43 is formed therein. The hollow section 43 is formed at a position that passes through the winding axis O.

[0019] Fig. Figure 2 is a perspective view schematically showing the electrode body 10. The electrode body 10 comprises a foil element 20, which is manufactured to surround the winding axis O. “D” denotes a direction in which the foil element 20 extends within the electrode body 10 in a wound state.

[0020] The foil element 20 is manufactured such that it is long in the winding direction D of the electrode body 10. The foil element 20 comprises a separator 21, a cathode foil 22, a separator 23 and an anode foil 24.

[0021] Fig. Figure 3 is a top view showing a cathode foil 22. The one in Fig. Figure 3 shows the cathode foil 22 in a state where it has been disassembled and unfolded from a state in which it was wound into the electrode body 10. The cathode foil 22 comprises long sides 30, 31 and short sides 32, 33. The long sides 30, 31 extend in an L1 direction, in which the cathode foil 22 extends. The L1 direction corresponds to the winding direction D in the wound state of the electrode body 10. The long side 30 is positioned at the first end section 5 of the electrode body 10 in the wound state, and the long side 31 is positioned at the second end section 6 of the electrode body 10 in the wound state.

[0022] The cathode foil 22 comprises a cathode current collector plate 25 and a cathode composite material layer 26. For example, the cathode current collector plate 25 is made of a metal material such as aluminum or an aluminum alloy.

[0023] The cathode composite material layer 26 contains an active cathode material, a binder, and other components. Examples of the active cathode material include LiCoO2, LiNo2, and LiMn2O4. The thickness of the cathode composite material layer 26 is, for example, 0.1 µm or more and 1000 µm or less.

[0024] The cathode composite material layer 26 can be produced on both the front and back sides of the cathode current collector plate 25, or on only one surface. The cathode foil 22 includes a cathode groove section 27 extending in the direction of the winding axis O, in which the cathode composite material layer 26 is not produced. A plurality of cathode groove sections 27 are produced in the direction in which the cathode foil 22 extends. The cathode composite material layer 26 is subdivided by the plurality of cathode groove sections 27. If the cathode composite material layer 26 is produced on both the front and back sides of the cathode current collector plate 25, the cathode groove section 27 can be produced on both cathode composite material layers 26, on the front and back sides, or on only one surface.If the cathode slot section 27 is produced on a surface, it is preferred that the surface is produced on a side that will become a winding outer side.

[0025] Fig. Figure 4 is a top view showing an anode foil 24. The in Fig. The anode foil 24 shown in Figure 4 is in a state in which it has been disassembled and unfolded from a state in which it was wound into the electrode body 10. The anode foil 24 comprises long sides 36, 37 and short sides 38, 39. The long sides 36, 37 extend in an L2 direction in which the anode foil 24 extends. The L2 direction corresponds to the winding direction D in the wound state of the electrode body 10. The long side 36 is positioned at the first end section 5 of the electrode body 10 in the wound state, and the long side 37 is positioned at the second end section 6 of the electrode body 10 in the wound state.

[0026] The anode foil 24 comprises an anode current collector plate 34 and an anode composite material layer 35. For example, the anode current collector plate 34 contains a metal material such as copper.

[0027] The anode composite material layer 35 contains an active anode material, a binder, and other components. Examples of active anode materials include graphite. The thickness of the anode composite material layer 35 is, for example, 0.1 µm or more and 1000 µm or less.

[0028] The anode composite material layer 35 can be produced on either the front or back side of the anode current collector plate 34, or on only one surface. The anode foil 24 includes an anode groove section 40 extending in the direction of the winding axis O, in which the anode composite material layer 35 is not produced. A plurality of anode groove sections 40 are produced in the direction in which the anode foil 24 extends. The anode composite material layer 35 is subdivided by the plurality of anode groove sections 40. If the anode composite material layer 35 is produced on both the front and back sides of the anode current collector plate 34, the anode groove section 40 can be produced on both anode composite material layers 35, on the front and back sides, or on only one surface.If the anode slot section 40 is produced on a surface, it is preferred that the surface is produced on a side that will become a winding outer side.

[0029] In Fig. 1 the anode composite material layer 35 is manufactured such that the length of the anode composite material layer 35 is longer than the length of the cathode composite material layer 26 in the Z direction.

[0030] Fig. Figure 5 is an expanded top view showing the state in which the foil element 20 is expanded and the foils are arranged. The foil element 20 is produced by placing the separator 23 on the anode foil 24, the cathode foil 22 on the separator 23, and the separator 21 on the cathode foil 22. The positions of the anode foil 24 and the cathode foil 22 can be interchanged.

[0031] Separator 21 and separator 23 are manufactured in an elongated shape. Separator 21 comprises long sides 70, 71 and short sides 72, 73. Separator 23 comprises long sides 75, 76 and short sides 77, 78.

[0032] In Fig. 5 The electrode body 10 comprises an electrode composite material layer 45, and the electrode composite material layer 45 comprises the cathode composite material layer 26 and the anode composite material layer 35. The electrode body 10 comprises a start-end section S of a wound body of the electrode body 10 and an end-end section E of the wound body of the electrode body 10.

[0033] In the Fig. In the example shown, short side 33 and short side 39 are positioned at the start-end section S. Short side 32 and short side 38 are positioned at the end-end section E. Short side 33 and short side 39 can differ from each other in the winding direction D. In this case, the start-end section S is a side that, in the wound state, is closer to the winding axis O. Similarly, if short side 32 and short side 38 differ from each other in the winding direction D, the end-end section E is a side that is farther from the winding axis O. In the example shown in Fig. In the example shown in Figure 5, the short sides 73, 78 of the separators 21, 23 are also positioned at the start-end section S, and the short sides 72, 73 are also positioned at the end-end section E. However, the separators 21, 23 can be manufactured such that they are longer in the winding direction D than the cathode foil 22 and the anode foil 24.

[0034] Fig. Figure 6 is a sectional view showing the cathode foil 22, the anode foil 24, the separator 21 and the separator 23. Fig. Figure 5 shows the cathode current collector plate 25 comprising a main surface 80 and a main surface 81. The cathode composite material layers 26 comprise a single-sided cathode composite material layer 82 produced on the main surface 80 and a single-sided cathode composite material layer 83 produced on the main surface 81.

[0035] The anode current collector plate 34 comprises a main surface 84 and a main surface 85. The anode composite material layers 35 comprise a single-sided anode composite material layer 86 produced on the main surface 84, and a single-sided anode composite material layer 87 produced on the main surface 85.

[0036] In the Fig. In the example shown in Figure 6, the start-end section S is positioned on the inside of the winding of the wound body on the right-hand side, and the end-end section E is positioned on the outside of the winding of the wound body on the left-hand side. The distances between the slot sections on the inside of the winding, i.e., the right-hand side in Figure 6, are shown in Figure 6. Fig. 6, are smaller than the distances between the slot sections on the outer side of the winding, i.e., the left side in Fig. 6. In Fig. In diagram 6, the inner side of the winding is labeled D1 and the outer side is labeled D2. The inner and outer sides of the winding are only examples and are limited to these.

[0037] The electrode body 10 is manufactured such that it surrounds the winding axis O from the start-end section S. Therefore, in the wound state, the curvature on the inside of the winding is greater than the curvature on the outside of the winding in the electrode body 10, so that the bending stress is higher on the inside of the winding.

[0038] Therefore, there is a risk of a crack forming in the electrode composite material layer 45 on the inside of the winding. However, in the energy storage cell 1 according to the embodiment, the electrode foil contains a plurality of slot sections in which the electrode composite material layer 45 is not produced. The distances between the slot sections on the inside of the winding are smaller than the distances between the slot sections on the outside of the winding. Therefore, the formation of a crack or the like in the electrode composite material layer 45 is prevented.

[0039] In the cathode foil 22, which is in Fig. As shown in Figure 6, the distances W1, W2, W3 between the cathode slot sections 27 on the inner side of the winding are smaller than the distances W4, W5, W6 between the cathode slot sections 27 on the outer side of the winding. In the anode foil 24, the distances X1, X2, X3 between the anode slot sections 40 on the inner side of the winding are smaller than the distances X4, X5, X6 between the anode slot sections 40 on the outer side of the winding.

[0040] It is preferred that the distance between the slot sections increases from the initial end section S to the final end section E. If slot sections are provided on the electrode composite material layer 45, the amount of active material contained in the electrode composite material layer 45 becomes small, and therefore the capacitance decreases. Therefore, the slot sections are not evenly distributed on the electrode composite material layer 45, and a larger number of slot sections are provided on the inside of the winding, where the bending stress is high, thus limiting the decrease in capacitance.

[0041] In the cathode foil 22, which is in Fig. As shown in Figure 6, it is preferred that the distance between the cathode slot sections 27 is W1 < W2 < W3 < W4 < W5 < W6. In the anode foil 24, it is preferred that the distance between the anode slot sections 40 is X1 < X2 < X3 < X4 < X5 < X6.

[0042] It is preferred that the slot widths of the slot sections on the inside of the winding are smaller than the slot widths of the slot sections on the outside of the winding. This is because it is possible to sufficiently prevent the formation of a crack or the like in the electrode composite material layer 45 on the inside of the winding, where the bending stress is high, even if the slot widths of the slot sections are small. Furthermore, this is because it is possible to adequately protect the area of ​​the sections in which the electrode composite material layer 45 is produced while the slot sections are in place.

[0043] At the in Fig. In the cathode foil 22 shown in Figure 6, it is preferred that the slot widths Y1, Y2, Y3, Y4 of the cathode slot sections 27 on the inside of the winding are smaller than the slot widths Y5, Y6, Y7 of the cathode slot sections 27 on the outside of the winding. In the anode foil 24, it is preferred that the slot widths Z1, Z2, Z3, Z4 of the anode slot sections 40 on the inside of the winding are smaller than the slot widths Z5, Z6, Z7 of the anode slot sections 40 on the outside of the winding.

[0044] It is preferred that the groove width of the groove section increases from the initial end section S to the final end section E. This is because the bending stress is higher in a section that is closer to the initial end section S.

[0045] In the cathode foil 22, which is in Fig. As shown in Figure 6, it is preferred that Y1 < Y2 < Y3 < Y4 < Y5 < Y6 < Y7 is satisfied as the slot width of the cathode slot section 27. In the anode foil 24, it is preferred that Z1 < Z2 < Z3 < Z4 < Z5 < Z6 < Z7 is satisfied as the slot width of the anode slot section 40.

[0046] It is preferred that the cathode groove sections 27 and the anode groove sections 40 are manufactured such that they face each other. If the anode groove sections 40 are located on the anode foil 24, there is a risk that the proportion of the cathode foil sections 22 facing the anode groove sections 40 will increase, leading to lithium deposition. Therefore, by manufacturing the cathode groove sections 27 and the anode groove sections 40 such that they face each other, the proportion of the cathode foil sections 22 facing the anode groove sections 40 is reduced, and thus lithium deposition can be limited.

[0047] In this case, it is preferred that the slot width of the anode slot section 40 is smaller than the slot width of the cathode slot section 27 opposite it. This further restricts lithium deposition.

[0048] In Fig. 6 is preferably Y1 > Z1, preferably Y2 > Z2, preferably Y3 > Z3, preferably Y4 > Z4, preferably Y5 > Z5, preferably Y6 > Z6 and preferably Y7 > Z7.

[0049] It should be understood that the embodiment disclosed herein is in every respect exemplary and not limiting. It is intended that the present invention is demonstrated by the claims, and all modifications within meanings and scopes equivalent to the claims are included. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2001 - 6 749 A

[0002]

Claims

[1] Power storage cell, comprising: an electrode body in which a foil element is wound so as to surround a winding axis; and a housing in which the electrode body is housed, wherein: the film element comprises an electrode film and a separator; the electrode foil comprises a current collector plate and an electrode composite material layer formed on the current collector plate; the electrode foil comprises a groove portion extending in the direction of the winding axis, in which the electrode composite material layer is not produced; a plurality of groove portions are formed in a direction in which the electrode foil extends; and a distance between the slot sections on an inner side of a winding is smaller than a distance between the slot sections on an outer side of a winding. [2] A power storage cell according to claim 1, wherein: the electrode body comprises a starting end portion of a wound body of the electrode body and a final end portion of the wound body of the electrode body; and the distances between the groove sections increase from the start-end section to the end-end section. [3] The power storage cell according to claim 1, wherein a groove width of the groove sections on the winding inner side is smaller than a groove width of the groove section on the winding outer side. [4] A power storage cell according to any one of claims 1 to 3, wherein: the electrode foil comprises a cathode foil and an anode foil; the cathode foil comprises a cathode current collector plate and a cathode composite material layer formed on the cathode current collector plate; the cathode foil comprises a cathode groove portion extending in the direction of the winding axis, in which the cathode composite material layer is not formed; the anode foil comprises an anode current collector plate and an anode composite material layer formed on the anode current collector plate; the anode foil comprises an anode groove section extending in the direction of the winding axis, in which the anode composite material layer is not produced; and the cathode groove portion and the anode groove portion are made to face each other. [5] The power storage cell according to claim 4, wherein a groove width of the anode groove portion is smaller than a groove width of the opposite cathode groove portion.

Images