All-solid-state battery

Abstract

An all-solid-state battery (1A) comprises a collector foil assembly (20A) that includes a plurality of collector foils that electrically connect an electrode stack (10) and a tab lead (30A). The collector foil assembly (20A) comprises a stacked portion (24) in which a plurality of collector foils are stacked so that adjacent collector foils are in contact with each other, and an interposed portion (23) that is formed from a plurality of collector foils extending from the electrode stack (10) toward the stacked portion (24). The stacked portion (24) includes a curved portion (242) that is formed by bending the plurality of collector foils.

Description

all solid state battery

[0001] The present invention relates to an all-solid-state battery.

[0002] BACKGROUND ART A battery is known that includes a battery element formed by stacking a plurality of unit battery elements, a tab extending from the battery element, and a lead joined to the tab (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2001-256960

[0004] In all-solid-state batteries using a metallic lithium negative electrode, the amount of expansion of the all-solid-state battery during charging and discharging is very large, and therefore, in the above-mentioned conventional technology, the tab cannot follow the expansion of the all-solid-state battery, resulting in breakage of the tab.

[0005] The problem to be solved by the present invention is to provide an all-solid-state battery capable of suppressing damage to a current collecting foil, and a method for manufacturing the same.

[0006] The present invention solves the above problem by providing a curved portion formed by curving multiple current collecting foils in a laminated portion in which multiple current collecting foils are stacked so that adjacent current collecting foils come into contact with each other.

[0007] According to the present invention, damage to the current collecting foil can be suppressed.

[0008] FIG. 1 is a plan view showing an all-solid-state battery according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 . FIG. 3 is a cross-sectional view showing an electrode laminate according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a method for producing a current collector foil assembly according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view showing a portion of an all-solid-state battery according to a second embodiment of the present invention. FIG. 6 is a cross-sectional view showing a portion of an all-solid-state battery according to a third embodiment of the present invention. FIG. 7 is a cross-sectional view showing a method for producing a current collector foil assembly according to the third embodiment of the present invention. FIG. 8 is a cross-sectional view showing a current collector foil assembly and a tab lead according to a fourth embodiment of the present invention. FIG. 9 is a cross-sectional view showing a portion of an all-solid-state battery according to a fifth embodiment of the present invention.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0010] Fig. 1 is a plan view showing an all-solid-state battery 1A in the first embodiment. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a cross-sectional view showing an electrode stack 10 in the first embodiment, illustrating a cross section corresponding to the cross section shown in Fig. 2.

[0011] As shown in FIGS. 1 and 2 , the all-solid-state battery 1A in this embodiment includes a plurality of electrode laminates 10, a pair of current collector foil assemblies 20A, 20B, a pair of tab leads 30A, 30B, and an exterior body 40.

[0012] A plurality of electrode laminates 10 are stacked along the Z direction in the figure via positive electrode current collector foils 21 or negative electrode current collector foils 25. As shown in Fig. 3, each electrode laminate 10 includes a positive electrode layer 11, a negative electrode layer 12, and a solid electrolyte layer 13, and these layers are stacked along the Z direction in the figure.

[0013] The positive electrode layer 11 contains at least a positive electrode active material capable of absorbing and releasing an alkali metal such as lithium (Li), sodium (Na), or potassium (K), and is not particularly limited, but preferably contains a positive electrode active material containing sulfur. The sulfur-containing positive electrode active material may be any material that utilizes a sulfur oxidation-reduction reaction to release alkali metal ions such as lithium ions during charging and absorb the alkali metal ions during discharging. The type of sulfur-containing positive electrode active material is not particularly limited, but particles or thin films of elemental sulfur (S), organic sulfur compounds, or inorganic sulfur compounds can be used.

[0014] The organic sulfur compound is not particularly limited, but examples thereof include disulfide compounds, sulfur-modified polyacrylonitrile, sulfur-modified polyisoprene, rubeanic acid (dithiooxamide), polycarbon sulfide, etc. The inorganic sulfur compound is not particularly limited, but examples thereof include S-carbon composite, TiS ２ , TiS ３ , TiS ４ , NiS, NiS ２ , CuS, FeS ２ , Li ２ S, MoS ２ , MoS ３The positive electrode active material may be one that does not contain sulfur.

[0015] The negative electrode layer 12 is made of lithium metal. This negative electrode layer 12 is made of lithium metal deposited on the main surface of the negative electrode current collector foil 25. The volume of this negative electrode layer 12 increases as lithium metal is deposited during charging of the all-solid-state battery 1A, but decreases as the lithium metal disappears (moves toward the positive electrode layer 11) during discharging.

[0016] The solid electrolyte layer 13 is provided between the positive electrode layer 11 and the negative electrode layer 12. The solid electrolyte layer 13 is made of, for example, a sulfide solid electrolyte or an oxide solid electrolyte. Although not particularly limited, it is preferable to use a sulfide solid electrolyte as the material for the solid electrolyte layer 13. As the sulfide solid electrolyte, for example, LiI-Li ２ S-SiS ２ , LiI-Li ２ S-P ２ O ５ , LiI-Li ３ P.O. ４ -P ２ S ５ , Li ２ S-P ２ S ５ , LiI-Li ３ P.S. ４ , LiI-LiBr-Li ３ P.S. ４ , Li ３ P.S. ４ , Li ２ S-P ２ S ５ , Li ２ S-P ２ S ５ - LiI, Li ２ S-P ２ S ５ -Li ２ O, Li ２ S-P ２ S ５ -Li ２ O-LiI, Li ２ S-SiS ２ , Li ２ S-SiS ２ - LiI, Li ２S-SiS ２ - LiBr, Li ２ S-SiS ２ -LiCl, Li ２ S-SiS ２ -B ２ S ３ - LiI, Li ２ S-SiS ２ -P ２ S ５ - LiI, Li ２ S-B ２ S ３ , Li ２ S-P ２ S ５ -Z ｍ S ｎ (where m and n are positive numbers, and Z is Ge, Zn, or Ga), Li ２ S-GeS ２ , Li ２ S-SiS ２ -Li ３ P.O. ４ , Li ２ S-SiS ２ -Li ｘ MO ｙ (where x and y are positive numbers, and M is any of P, Si, Ge, B, Al, Ga, and In). ２ S-P ２ S ５ " The statement Li ２ S and P ２ S ５ The same applies to the other descriptions above. Alternatively, sulfide glass or the like may be used as the sulfide solid electrolyte.

[0017] As the oxide solid electrolyte, for example, a compound having a NASICON structure can be used. Examples of the compound having a NASICON structure include compounds represented by the general formula Li １＋ｘ Al ｘ Ge ２－ｘ (P.O. ４ ) ３ (0≦x≦2) (LAGP), a compound represented by the general formula Li １＋ｘ Al ｘ Ti ２－ｘ(P.O. ４ ) ３ (0≦x≦2) (LATP) and the like can be used. In addition, other oxide solid electrolytes include LiLaTiO (for example, Li ０．３４ La ０．５１ TiO ３ ), LiPON (e.g., Li ２．９ P.O. ３．３ N ０．４６ ), LiLaZrO (e.g., Li ７ La ３ Zr ２ O １２ ) etc. can be used.

[0018] Since the current collector foil assembly 20A and the current collector foil assembly 20B have substantially the same configuration, the current collector foil assembly 20A will be mainly described here.

[0019] As shown in FIG. 2 , the current collector foil assembly 20A is composed of a plurality of positive current collector foils 21. The positive current collector foils 21 are conductive foil-shaped members and are made of, for example, a metal, although not limited thereto. Examples of metals that can be used include aluminum, nickel, iron, stainless steel, titanium, and copper. Alternatively, a clad material of nickel and aluminum, or a clad material of copper and aluminum may be used. Alternatively, the positive current collector foils 21 may be made of a conductive resin. Examples of such resins include resins in which a conductive filler is added to a non-conductive polymer material.

[0020] The positive electrode current collector foil 21 contacts the positive electrode layer 11 (see FIG. 3) of the electrode laminate 10 and is joined to the tab lead 30A, thereby electrically connecting the electrode laminate 10 to the tab lead 30A.

[0021] As shown in Fig. 2, the current collector foil assembly 20A includes a contact portion 22, an intervening portion 23, and a laminated portion 24. The contact portion 22 is interposed between a pair of electrode laminates 10 and is in contact with the positive electrode layer 11 (see Fig. 3) of the electrode laminate 10. As shown in Fig. 2, in this embodiment, the contact portion 22 extends substantially parallel to the main surfaces (upper and lower surfaces) of the electrode laminate 10.

[0022] The interposed portion 23 is connected to the contact portion 22 and extends from the electrode stack 10 toward the stack portion 24. In Fig. 2, in the interposed portion 23, each positive current collector foil 21 has a parallel portion that extends parallel to the side surface of the electrode stack 10 (Z direction in the figure), but this is not limiting. The extension direction of the positive current collector foil 21 in the interposed portion 23 changes according to the expansion and contraction of the electrode stack 10 that accompanies charge and discharge.

[0023] The laminated portion 24 is connected to the interposed portion 23 and extends from the interposed portion 23 toward the tab lead 30A. The laminated portion 24 is a portion where a plurality of positive current collector foils 21 are stacked so that adjacent positive current collector foils 21 are in contact with each other. In this embodiment, the plurality of positive current collector foils 21 are stacked so that adjacent positive current collector foils 21 are in contact with each other in the stacking direction of the electrode stack 10 (the Z direction in the figure). As will be described in detail later, such a laminated portion 24 can be formed by pressing the plurality of stacked positive current collector foils 21 from above and below (the ±Z directions).

[0024] The laminated portion 24 includes a first end portion 241, a curved portion 242, a second end portion 243, and a joint portion 244. The first end portion 241 is connected to one end of the curved portion 242 in the extension direction (X direction in the figure) of the positive current collector foil 21 in the laminated portion 24. The first end portion 241 extends linearly from the interposed portion 23 along the −X direction in the figure.

[0025] The curved portion 242 is connected to the first end portion 241. The curved portion 242 is formed by bending the plurality of positive current collector foils 21. Although not particularly limited, the plurality of positive current collector foils 21 are not joined to each other at the curved portion 242.

[0026] In this embodiment, the curved portion 242 is curved so as to protrude in a first direction (the +Z direction in the figure). Note that the curved portion 242 may be curved so as to protrude in a second direction (the -Z direction in the figure), which is the opposite direction to the first direction. Alternatively, the protruding direction may be inclined with respect to the Z direction.

[0027] Furthermore, the curved portion 242 in this embodiment does not face the main surfaces (upper surface 31 and lower surface 32) of the tab lead 30A. This curved portion 242 is formed in the current collector foil assembly 20A between the tab lead 30A and the electrode stack 10, and is not in contact with the tab lead 30A.

[0028] A second end 243 is connected to the other end of the curved portion 242. The second end 243 extends in a direction (the X direction in the figure) that is substantially parallel to the first end 241. In this embodiment, the second end 243 extends linearly from the other end of the curved portion 242 in the −X direction in the figure.

[0029] A joint portion 244 is connected to the second end portion 243. The joint portion 244 is in contact with the main surface of the tab lead 30A and is joined to the main surface of the tab lead 30A. The joint portion 244 and the tab lead 30A may be joined by, for example, spot welding.

[0030] The tab lead 30A is a conductive plate-shaped member. In this embodiment, the tab lead 30A is provided at a position corresponding to approximately the center of the electrode stack 10 in the stacking direction of the electrode stack 10. In other words, the tab lead 30A is located at approximately the center of the all-solid-state battery 1A in the stacking direction.

[0031] The tab lead 30A is made of, for example, a metal or a conductive resin. Although not particularly limited, the tab lead 30A may be made of the same material as the positive electrode current collector foil 21.

[0032] 1 and 2 , the current collector foil assembly 20B is made up of a plurality of negative electrode current collector foils 25. The negative electrode current collector foils 25 are conductive foil-shaped members. The material constituting the negative electrode current collector foils 25 can be the same as the material constituting the positive electrode current collector foil 21. Note that the material constituting the negative electrode current collector foils 25 may be different from the material constituting the positive electrode current collector foil 21.

[0033] As described above, the current collector foil assembly 20B in this embodiment has substantially the same configuration as the current collector foil assembly 20A. That is, the current collector foil assembly 20B in this embodiment includes a contact portion interposed between the electrode stacks 10, an interposed portion interposed between the tab lead 30B and the electrode stack 10, and a laminate portion including the curved portion and the like as described above.

[0034] However, the current collector foil assembly 20B may have a different configuration from the current collector foil assembly 20A. Alternatively, the current collector foil assembly 20B may have the configuration of the current collector foil assembly 20A in this embodiment as shown in Fig. 2, and the current collector foil assembly 20A may not have the configuration of this embodiment as shown in Fig. 2.

[0035] The tab lead 30B is made of, for example, a metal or a conductive resin, similar to the tab lead 30A. Although not particularly limited, the tab lead 30B may be made of the same material as the negative electrode current collector foil 25.

[0036] The exterior body 40 houses a plurality of electrode stacks 10 and a pair of current collector foil assemblies 20A, 20B. The pair of tab leads 30A, 30B extend from the interior of the exterior body 40 to the exterior of the exterior body 40. Although not particularly limited, the exterior body 40 can be produced by bonding the outer peripheries of two laminate films together by thermocompression bonding or the like.

[0037] In the all-solid-state battery 1A according to the present embodiment as described above, the laminated portion 24 of the current collector foil assemblies 20A, 20B is provided with a curved portion 242. This allows the excess length of the positive and negative current collector foils 21, 25 to be increased without being restricted by the distance between the electrode laminate 10 and the tab leads 30A, 30B. Therefore, when the electrode laminate 10 expands due to charging, the curved portion 242 extends, thereby reducing the tensile load applied to the positive and negative current collector foils 21, 25 and suppressing breakage of the positive and negative current collector foils 21, 25.

[0038] Furthermore, by providing the curved portion 242 in the laminated portion 24, the strength of the curved portion 242 of this embodiment against a tensile load can be improved compared to when a portion where no current collector foil is laminated is curved as in Patent Document 1. Therefore, damage to the positive and negative current collector foils 21, 25 can be further suppressed.

[0039] Furthermore, when a sulfide-based solid electrolyte is used as the solid electrolyte, residual water vapor or the like in the cell reacts with the electrolyte and deteriorates it, so the pressure inside the cell is reduced (evacuated) to prevent residual water vapor or the like. At this time, the tab leads may be pulled into the cell. In contrast, in the all-solid-state battery 1A of this embodiment, the tab leads are in close contact with each other at the curved portion 242, so pulling in of the tab leads can be prevented.

[0040] Furthermore, as in Patent Document 1, if the tab leads are arranged at the ends in the stacking direction and the joints are arranged at those ends, the current collector foil farthest from the ends is susceptible to damage due to the influence of the expansion of all of the electrode stack 10. On the other hand, in this embodiment, the tab leads 30A, 30B are arranged at approximately the center in the stacking direction of the all-solid-state battery 1A, and therefore the stacking portion 24 is also arranged at approximately the center in the stacking direction. This makes it possible to reduce the tensile load applied to the positive and negative current collector foils 21, 25 located near the ends in the stacking direction, thereby suppressing damage to the positive and negative current collector foils 21, 25.

[0041] Here, an example of a method for producing the above-described current collector foil assembly 20A when producing the all-solid-state battery 1A will be described with reference to Fig. 4. Fig. 4 is a cross-sectional view showing a method for producing the current collector foil assembly 20A in the first embodiment. Note that, in this embodiment, a form in which the curved portion 242 is formed using a pressing jig 100 in the step of joining the tab lead 30A and the positive electrode current collector foil 21 is described, but the present invention is not limited to this. The curved portion 242 may be formed in a step separate from the joining step.

[0042] 4 , first, a plurality of electrode stacks 10 are stacked via a plurality of positive and negative electrode current collector foils 21, 25. Then, a plurality of positive electrode current collector foils 21 extending from the electrode stack 10 are clamped and fixed by a pressing jig 100. In this embodiment, the plurality of positive electrode current collector foils 21 are clamped by the pressing jig 100 at positions corresponding to approximately the center of the electrode stack 10 in the stacking direction of the electrode stack 10.

[0043] The pressing jig 100 includes a pair of upper and lower pressing members 101 and 102. The pressing member 101 has a pressing surface 101a that presses the positive current collector foil 21 from above, and this pressing surface 101a includes a concavely curved surface that corresponds to the upper surface of the curved portion 242. Similarly, the pressing member 102 has a pressing surface 102a that presses the positive current collector foil 21 from below, and this pressing surface 101a includes a convexly curved surface that corresponds to the lower surface of the curved portion 242. When the multiple positive current collector foils 21 are pressed by these pressing surfaces 101a and 102a, the shapes of the pressing surfaces 101a and 102b are transferred to the multiple positive current collector foils 21, thereby forming the curved portion 242 and the first and second end portions 241 and 243.

[0044] Furthermore, the pressing member 101 has a pressing surface 101b that presses the positive current collector foil 21 from the left side, and similarly, the pressing member 102 has a pressing surface 102b that presses the positive current collector foil 21 from the left side. These pressing surfaces 101b, 102b are surfaces that are approximately parallel to the side surfaces of the electrode stack 10. In the forming process of this embodiment, the pressing members 101, 102 press the positive current collector foil 21 toward the side surfaces of the electrode stack 10, thereby forming parallel portions in the interposed portions 23 that extend approximately parallel to the side surfaces of the electrode stack 10.

[0045] In this way, by forming parallel portions in the interposition portion 23, the excess length of the positive and negative electrode current collector foils 21, 25 can be increased without being restricted by the gap between the electrode stack 10 and the tab leads 30A, 30B, and therefore breakage of the positive and negative electrode current collector foils 21, 25 can be suppressed.

[0046] After the multiple positive current collector foils 21 are fixed using the holding jig 100, they are bonded using a bonding device 200. The bonding device 200 in this embodiment is, but is not limited to, an ultrasonic welding device. The bonding device 200 includes a horn 201 and an anvil 202. In the bonding process in this embodiment, the horn 201 and the anvil 202 clamp and pressurize the tips of the multiple positive current collector foils 21 and the tab leads 30A, and ultrasonic waves are generated from the horn 201 to weld the tips of the multiple positive current collector foils 21 and the tab leads 30A together. This forms a bonded portion 244. In this manner, the current collector foil assembly 20A is fabricated. Although not specifically shown, the current collector foil assembly 20B can also be formed using this method. After this bonding process, the electrode stack 10 is housed in the exterior body 40, thereby fabricating the all-solid-state battery 1A.

[0047] As described above, by producing the collector foil assembly 20A using the clamping jig 100 used in the joining process, the curved portion 242 and the first and second end portions 241, 243 can be formed simultaneously with the joint portion 244, thereby shortening the takt time.

[0048] In the first embodiment, one curved portion 242 is provided, but this is not limiting. As shown in Fig. 5, the curved portion 242 may be provided with a plurality of curved portions 242a, 242b. Fig. 5 is a cross-sectional view showing a portion of an all-solid-state battery 1B according to a second embodiment.

[0049] The curved portion 242 in the second embodiment includes a first curved portion 242a and a second curved portion 242b. Similar to the first embodiment, the first curved portion 242a is curved so as to protrude in a first direction (the +Z direction in the figure). On the other hand, the second curved portion 242b is curved so as to protrude in a second direction (the -Z direction in the figure). Note that the second curved portion 242b may also be curved so as to protrude in the first direction.

[0050] In this way, by providing a plurality of curved portions 242a, 242b, the excess length of the positive and negative current collector foils 21, 25 can be further increased, and therefore breakage of the positive and negative current collector foils 21, 25 can be further suppressed.

[0051] Furthermore, if the extra length is significantly increased by one curved portion 242, the size of the curved portion 242 increases, but by providing multiple curved portions 242 a, 242 b, the size of each of the curved portions 242 a, 242 b can be set small, thereby suppressing an increase in the size of the all-solid-state battery 1B.

[0052] Furthermore, the multiple curved portions 242 a, 242 b function as springs when the all-solid-state battery 1B contracts, and can prevent the positive and negative electrode current collector foils 21, 25 from bending due to the restoring force (tensile force) of the multiple curved portions 242 a, 242 b.

[0053] Furthermore, by providing the curved portions 242 a, 242 b that are curved so as to protrude in opposite directions to each other, the space for forming excess length is increased, and the excess length of the positive and negative electrode current collector foils 21, 25 can be increased without being restricted by the gap between the electrode stack 10 and the tab lead 30A. Therefore, even in a thicker all-solid-state battery, the tensile load on the positive and negative electrode current collector foils 21, 25 during expansion can be reduced, and damage to the positive and negative electrode current collector foils 21, 25 can be suppressed.

[0054] In the second embodiment, the curved portions 242 a, 242 b are aligned along the extension direction of the positive electrode current collector foil 21, but this is not limited thereto. As shown in Fig. 6, the curved portions 242 a, 242 b may be aligned along the stacking direction. Fig. 6 is a cross-sectional view showing a portion of an all-solid-state battery 1C according to a third embodiment.

[0055] In the curved portion 242 according to the third embodiment, the first curved portion 242 a and the second curved portion 242 b are aligned in the stacking direction, i.e., the first curved portion 242 a overlaps with the second curved portion 242 b when viewed from the stacking direction.

[0056] In the third embodiment, the first curved portion 242a is formed by some of the positive current collector foils 21, and the second curved portion 242b is formed by the remaining positive current collector foils 21. Therefore, the curved portion 242 is divided in the stacking direction by a gap 242c formed between the first curved portion 242a and the second curved portion 242b.

[0057] By providing such curved portions 242, it is possible to reduce the curvature of the positive current collector foil 21 inside the first and second curved portions 242a, 242b, thereby suppressing plastic deformation of the positive current collector foil 21. Therefore, it is possible to increase the protrusion amount of the first and second curved portions 242a, 242b without being limited by the gap between the electrode stack 10 and the tab lead 30A, and therefore it is possible to increase the excess length that can be provided to the positive current collector foil 21.

[0058] Here, an example of a method for producing the above-described current collector foil assembly 20A when producing the all-solid-state battery 1C will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view showing a method for producing the current collector foil assembly 20A in the third embodiment.

[0059] 7 , the pressing jig 100 includes a pair of upper and lower pressing members 101, 102, as well as a core 103. The core 103 is positioned between the pressing members 101, 102 and is inserted between the positive current collector foils 21 in the stacking direction. The core 103 divides the plurality of positive current collector foils 21 into upper and lower halves, thereby forming the first and second curved portions 242 a, 242 b as described above.

[0060] In the second and third embodiments, the curvatures of the curved portions 242 a, 242 b are the same, but the curvatures of the curved portions 242 a, 242 b may be different as shown in Fig. 8. The curved portions 242 a, 242 b may be formed to be aligned along the stacking direction.

[0061] 8 is a cross-sectional view showing a current collector foil assembly 20A and a tab lead 30A according to the fourth embodiment. As shown in FIG. 8, the curved portion 242 according to the fourth embodiment includes two first curved portions 242a. １ , 242a ２ In this embodiment, the first curved portion 242a includes a first curved portion 242b. １ , the second curved portion 242b, and the first curved portion 242a ２ and are arranged in this order from the electrode stack 10 side toward the tab lead 30A side.

[0062] Each curved portion 242a １, 242b, 242a ２ The curvature of the first curved portion 242a increases as it approaches the electrode stack 10. １ Curvature R ａ１ is the curvature R of the second curved portion 242b ｂ and the curvature R of the second curved portion 242b is smaller than ｂ is the first curved portion 242a ２ Curvature R ａ２ is smaller than (R ａ１ <R ｂ <R ａ２ ).

[0063] The greater the curvature of the curved portion, the greater the bending rigidity of the curved portion, making it more difficult for the curved portion to deform in the bending direction of the positive current collector foil 21. When the electrode laminate 10 expands, because the positive current collector foil 21 is joined to the tab lead 30A, the portion closer to the tab lead 30A experiences less bending deformation, while the portion closer to the electrode laminate 10 experiences greater bending displacement. Therefore, by reducing the bending rigidity of the portion of the positive current collector foil 21 close to the electrode laminate 10, the portion of the positive current collector foil 21 near the electrode laminate 10 can more easily follow the expansion of the electrode laminate 10, thereby further suppressing damage to the positive current collector foil 21.

[0064] In the fourth embodiment, a plurality of curved portions 242a １ , 242b, 242a ２ The curvature of the curved portions varies along the extension direction of the positive current collector foil 21, but as shown in FIG. 9 , multiple curved portions may vary along the width direction of the positive current collector foil 21 (the Y direction in the drawing).

[0065] 9A and 9B are cross-sectional views showing a portion of an all-solid-state battery 1D according to the fifth embodiment. Fig. 9A is a cross-section taken along line IXA-IXA in Figs. 9B and 9C, and shows a cross-section taken along the width direction of the laminated portion 24. Fig. 9B is a cross-section taken along line IXB-IXB in Fig. 9A, and Fig. 9C is a cross-section taken along line IXC-IXC in Fig. 9A.

[0066] As shown in FIGS. 9A to 9C, the laminated portion 24 in the fifth embodiment has a first curved portion 242a at approximately the center in the width direction. １On the other hand, at the edge in the width direction, the first curved portion 242a ２ , 242a ３ , 242a ４ It has the following characteristics.

[0067] In the fifth embodiment, each curved portion 242a １ ~242a ４ The curvature of the first curved portion 242a increases toward the edge in the width direction of the positive current collector foil 21. １ Curvature R １ is the first curved portion 242a ２ , 242a ３ , 242a ４ The curvature R of each ２ , R ３ , R ４ is smaller than (R １ <R ２ , R ３ , R ４ ).

[0068] The pressure inside the exterior body 40 is generally negative, and therefore, due to this negative pressure and atmospheric pressure, a force that crushes the all-solid-state battery 1D acts from the outside of the all-solid-state battery 1D. As shown in FIG. 9A, around the stacked portion 24, a force P １ On the other hand, near the edge of the laminated portion 24, a force P ２ and a force P from an oblique direction ３ Therefore, a large force is applied to the edge of the laminated portion 24. In contrast, in the laminated portion 24 of the fifth embodiment, the curved portion 242a ２ , 242a ３ , 242a ４ By increasing the curvature of the laminated portion 24, the rigidity of the edge of the laminated portion 24 can be improved, and damage to the edge of the laminated portion 24 can be suppressed.

[0069] In the second to fifth embodiments, the current collector foil assembly 20B may have a configuration similar to that of the current collector foil assembly 20A.

[0070] DESCRIPTION OF SYMBOLS 1A to 1D... All-solid-state battery 10... Electrode laminate 11... Positive electrode layer 12... Negative electrode layer 13... Solid electrolyte layer 20A, 20B... Current collector foil assembly 21... Positive electrode current collector foil 22... Contact portion 23... Interposition portion 24... Laminated portion 241... First end portion 242... Curved portion 242a... First curved portion 242b... Second curved portion 243... Second end portion 244... Joint portion 25... Negative electrode current collector foil 30A, 30B... Tab lead 40... Exterior body

Claims

1. An all-solid-state battery comprising: an electrode laminate formed by laminating a solid electrolyte layer and an electrode including a metallic lithium negative electrode; an exterior housing that houses the electrode laminate; a tab lead extending from the inside of the exterior housing to the outside of the exterior housing; and a current collecting foil assembly including a plurality of current collecting foils that electrically connect the electrode laminate and the tab lead, wherein the current collecting foil assembly comprises a laminate portion in which the plurality of current collecting foils are laminated so that adjacent current collecting foils are in contact with each other, and an intervening portion made up of the plurality of current collecting foils extending from the electrode laminate toward the laminate portion, and the laminate portion includes a curved portion formed by curving the plurality of current collecting foils.

2. An all-solid-state battery according to claim 1, wherein the laminated portion includes a plurality of the curved portions.

3. An all-solid-state battery according to claim 2, wherein the plurality of curved portions include first curved portions that curve so as to protrude in a first direction along the stacking direction of the solid electrolyte layer and the electrodes, and second curved portions that curve so as to protrude in a second direction that is the opposite direction to the first direction.

4. An all-solid-state battery according to claim 3, wherein the first curved portion overlaps the second curved portion when viewed from the stacking direction, and the curved portions are divided in the stacking direction by a gap formed between the first curved portion and the second curved portion.

5. An all-solid-state battery according to claim 2, wherein the plurality of curved portions are arranged from the electrode stack side toward the tab lead side, and the curvature of each of the curved portions decreases with increasing proximity to the electrode stack.

6. An all-solid-state battery according to claim 2, wherein the plurality of curved portions are arranged along the width direction of the current collector foil, and the curvature of each curved portion increases as it approaches an edge of the current collector foil in the width direction.

7. An all-solid-state battery according to any one of claims 1 to 6, wherein the laminated portion contacts a main surface of the tab lead and further includes a joining portion joined to the main surface of the tab lead, and the curved portion does not face the main surface of the tab lead.

8. An all-solid-state battery according to any one of claims 1 to 7, wherein the laminated portion includes a first end connected to one end of the curved portion in the extension direction of the current collecting foil, and a second end connected to the other end of the curved portion in the extension direction of the current collecting foil, and the first end extends substantially parallel to the second end.

9. A method for manufacturing an all-solid-state battery, comprising bending a plurality of overlapping current collecting foils with a pressing jig, thereby forming a curved portion in a stack of the plurality of current collecting foils so that adjacent current collecting foils come into contact with each other.

10. A method for manufacturing an all-solid-state battery according to claim 9, wherein the pressing jig comprises a pair of pressing members that sandwich the plurality of current collecting foils, the pair of pressing members each including a pressing surface that presses the plurality of current collecting foils, and the pressing surfaces include curved surfaces that have a shape corresponding to the curved portion.

11. A method for manufacturing an all-solid-state battery according to claim 9 or 10, comprising a joining step of forming a joint in the laminated portion by joining the plurality of current collecting foils to a tab lead using a joining device, wherein the joining step includes forming the joint while the plurality of current collecting foils are held by the pressing jig.

12. A method for manufacturing an all-solid-state battery according to any one of claims 9 to 11, wherein the plurality of current collecting foils extend from the side surfaces of an electrode laminate in which a solid electrolyte layer and an electrode are laminated, and the pressing jig presses the plurality of current collecting foils against the side surfaces of the electrode laminate, thereby forming parallel portions in the plurality of current collecting foils that are approximately parallel to the side surfaces of the electrode laminate.

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