Solid-state battery

Abstract

This solid-state battery (1) comprises a power generation element (20) in which a positive electrode current collector (11), a positive electrode layer (12), a solid electrolyte layer (13) containing a solid electrolyte, a negative electrode layer (14), and a negative electrode current collector (15) are laminated in this order in the Z direction, wherein: the positive electrode current collector (11) and the negative electrode current collector (12) are extended in a direction away from the power generation element (20); an insulating part (16), which is disposed between the positive electrode current collector (11) and the negative electrode current collector (12) and surrounds the positive electrode layer (12), the solid electrolyte layer (13), and the negative electrode layer (14) of the power generation element (20), is provided; the insulating part (16) has a first insulating part (17) which includes a first section (171) that covers a surface orthogonal to the positive electrode current collector (11) in the Z direction and a second section (172) that rises in the Z direction from the first section (171) and covers an outer peripheral side-surface (121) of the positive electrode layer (12) along the Z direction, and a second insulating part (18) which is disposed between the positive electrode current collector (11) and the negative electrode current collector (15) and covers the surface of the power generation element (20) that is not covered by the first insulating part (17), and the first insulating part (17); and when a direction which is orthogonal to the Z direction and approaches or separates from the power generation element (20) is defined as a second direction, the width (LI1) of the first section (171) along the second direction is greater than the width (LI2) of the second section (172) along the second direction.

Description

solid state battery

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

[0002] In a conventional solid-state battery in which a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector are stacked in a predetermined stacking direction, a sealing layer is provided to surround the periphery of the solid electrolyte layer and seal the gap between the positive electrode current collector and the negative electrode current collector (see, for example, Patent Document 1). In Patent Document 1, the positive electrode layer and the negative electrode layer face each other in the stacking direction between the positive electrode current collector and the negative electrode current collector, with the solid electrolyte layer interposed therebetween, and the solid electrolyte layer is filled around the periphery of the positive electrode layer and the negative electrode layer. The periphery of the solid electrolyte layer has a side surface along the stacking direction, and a sealing layer is provided to cover the side surface.

[0003] International Publication No. 2020 / 137388

[0004] However, in the solid-state battery of Patent Document 1, the adhesive surface between the solid electrolyte layer and the sealing layer is small. Therefore, there is a risk that the solid-state battery may be subjected to vibration or impact, resulting in delamination between the solid-state electrolyte layer and the sealing layer. If delamination occurs between the solid-state electrolyte layer and the sealing layer, a space is formed between the solid-state electrolyte layer and the sealing layer. When a confining pressure is applied to the solid-state battery along the stacking direction, pressure may be concentrated in the space, causing the solid-state electrolyte layer to fracture, and the fractured area may cause a short circuit between the positive electrode layer and the negative electrode layer.

[0005] An object of the present invention is to provide a solid-state battery that suppresses breakage of the solid electrolyte layer.

[0006] A solid-state battery according to one embodiment of the present invention includes a power generating element including a positive electrode current collector, a positive electrode layer, a solid electrolyte layer containing a solid electrolyte, a negative electrode layer, and a negative electrode current collector stacked in this order in a first direction. The positive electrode current collector and the negative electrode current collector extend in a direction away from the power generating element. An insulating portion is disposed between the positive electrode current collector and the negative electrode current collector and surrounds the positive electrode layer, the solid electrolyte layer, and the negative electrode layer of the power generating element. The insulating portion includes a first insulating portion and a second insulating portion. The first insulating portion includes a first portion covering a surface of the positive electrode current collector perpendicular to the first direction, and a second portion rising from the first portion in the first direction and covering an outer peripheral side surface of the positive electrode layer along the first direction. The second insulating portion is disposed between the positive electrode current collector and the negative electrode current collector and covers the first insulating portion and the surface of the power generating element not covered by the first insulating portion. A direction perpendicular to the first direction and moving toward and away from the power-generating element is defined as a second direction, and the length in the second direction from the surface of the part that contacts the positive electrode layer to the outer peripheral side surface of the part is greater than the length in the second direction from the surface of the second part that contacts the positive electrode layer to the outer peripheral side surface of the second part.

[0007] With this configuration, the contact area between the first insulating portion and the second insulating portion is increased, and even when the solid-state battery is subjected to vibration or impact, the first insulating portion and the second insulating portion are less likely to peel off, thereby suppressing the inconvenience of the solid electrolyte layer breaking due to the generation of a space caused by peeling.

[0008] 1 is a cross-sectional view showing a schematic configuration of a solid-state battery according to a first embodiment; 2 is a plan view of a main part of a battery according to the first embodiment; 3 is a cross-sectional view of the main part of a battery taken along line A-A in FIG. 2; 4 is a cross-sectional view of a main part of a battery according to a second embodiment; 5 is a cross-sectional view of a main part of a battery according to a third embodiment; 6 is a cross-sectional view of a main part of a battery according to a fourth embodiment;

[0009] First Embodiment A solid-state battery according to a first embodiment of the present disclosure will be described below. FIG. 1 is a cross-sectional view schematically illustrating the overall configuration of a solid-state battery according to this embodiment. As shown in FIG. 1, the solid-state battery 1 according to this embodiment includes a battery main part 2, an electrode tab 3, and an exterior material 4. The battery main part 2 and the electrode tab 3 are electrically connected. The exterior material 4 accommodates the battery main part 2 and the electrode tab 3, with a portion of the electrode tab 3 extending (exposed) to the outside. The electrode tab 3 includes a positive electrode tab 3A and a negative electrode tab 3B. The direction from the positive electrode tab 3A toward the negative electrode tab 3B is defined as the X direction.

[0010] FIG. 2 is a plan view of the battery main part 2 of FIG. 1 , and FIG. 3 is a cross-sectional view of the battery main part 2 taken along line A-A in FIG. 2 , particularly an enlarged view of the vicinity of the outer periphery of the battery main part 2. Note that in FIG. 2 , the solid electrolyte layer 13, the negative electrode layer 14, the negative electrode current collector 15, and the second insulating part 18 constituting the insulating part 16 are omitted from illustration in order to facilitate understanding of the shape of the first insulating part 17 constituting the insulating part 16 and its positional relationship with the positive electrode layer 12. As shown in FIG. 3 , the battery main part 2 includes a positive electrode current collector 11, a positive electrode layer 12, the solid electrolyte layer 13, the negative electrode layer 14, the negative electrode current collector 15, and the insulating part 16. The positive electrode current collector 11, the positive electrode layer 12, the solid electrolyte layer 13, the negative electrode layer 14, and the negative electrode current collector 15 are stacked in a Z direction (first direction) perpendicular to the X direction. The direction perpendicular to the X and Z directions is the Y direction. In the battery main part 2, the positive electrode current collector 11, the positive electrode layer 12, the solid electrolyte layer 13, the negative electrode layer 14, and the negative electrode current collector 15 are referred to as a power generating element 20.

[0011] The positive electrode current collector 11 is formed in a rectangular shape using a metal foil such as SUS (Steel Use Stainless Steel), aluminum, nickel, iron, stainless steel, titanium, or copper. A positive electrode layer 12 is laminated on each of the +Z side surface and the −Z side surface of the positive electrode current collector 11. The positive electrode current collector 11 is connected to a positive electrode tab 3A. Note that, for ease of understanding, FIG. 3 shows only the positive electrode layer 12 laminated on the +Z side surface of the positive electrode current collector 11.

[0012] The positive electrode layer 12 is made of a positive electrode active material. The positive electrode layer 12 contains, for example, a positive electrode active material, a sulfide solid electrolyte, a conductive additive, a binder, and xylene. The positive electrode active material is, for example, LiMn ２ O ４ , LiCoO ２ , LiNiO ２ , Li(Ni-Mn-Co)O ２ Examples of such materials include lithium-transition metal composite oxides, lithium-transition metal phosphate compounds, and lithium-transition metal sulfate compounds, in which a portion of these transition metals has been substituted with other elements. While an example in which the positive electrode layer 12 uses a lithium compound is shown here, batteries using other metals may also be used. The positive electrode layer 12 is formed, for example, by weighing out predetermined amounts of the above materials, mixing them to prepare a slurry, and applying and drying the prepared slurry on the positive electrode current collector 11.

[0013] As shown in FIG. 2 , the positive electrode layer 12 is formed in a rectangular shape in a plan view seen from the Z direction, and the rectangular outer peripheral edge (the outer peripheral side surface 121 of the positive electrode layer 12) is located inside the outer peripheral edge of the positive electrode current collector 11. In other words, the positive electrode layer 12 is laminated on a part of the positive electrode current collector 11. Furthermore, as will be described in detail later, a first insulating portion 17 constituting the insulating portion 16 is disposed on the outer peripheral portion of the positive electrode layer 12 when seen from the Z direction. In this embodiment, an end face 172B of the first insulating portion 17 on the solid electrolyte layer 13 side is parallel to the XY plane and is flush with an end face 122 of the positive electrode layer 12 on the solid electrolyte layer 13 side.

[0014] The solid electrolyte layer 13 is formed in a rectangular shape in a plan view seen from the Z direction, and is disposed so as to cover the positive electrode layer 12 and a portion of the second insulating portion 18. The solid electrolyte layer 13 contains a solid electrolyte as a main component. For example, the solid electrolyte is produced by weighing out predetermined amounts of a sulfide solid electrolyte, a binder, and xylene, mixing these to prepare a slurry, and applying the slurry to one side of an SUS foil and drying it. Note that the solid electrolyte layer 13 only needs to contain an inorganic solid electrolyte as a main component, and may further contain a liquid electrolyte, a polymer electrolyte, or a gel electrolyte.

[0015] The anode layer 14 is laminated on the solid electrolyte layer 13. The anode layer 14 is configured to have the same size as the cathode layer 12 when viewed from the Z direction, and is disposed so as to overlap the cathode layer 12 with the solid electrolyte layer 13 interposed therebetween. The anode layer 14 is formed, for example, by weighing out predetermined amounts of carbon black and a conductive metal as anode active materials, a binder, and NMP (N-methylpyrrolidone), mixing these to form a slurry, and applying the slurry to the anode current collector 15 and drying the slurry. The anode layer 14 may be provided only in a region overlapping with the cathode layer 12 when viewed from the Z direction, or may be provided so as to cover the entire end surface of the cathode layer 12 and the solid electrolyte layer 13 on the anode layer 14 side.

[0016] Like the positive electrode current collector 11, the negative electrode current collector 15 is formed into a rectangular shape using a metal foil such as SUS, aluminum, nickel, iron, stainless steel, titanium, or copper. A negative electrode layer 14 is laminated on each of the +Z side surface and the −Z side surface of the negative electrode current collector 15. The negative electrode current collector 15 is connected to the negative electrode tab 3B. Note that, for ease of understanding, FIG. 3 shows only the positive electrode layer 12 laminated on the +Z side surface of the positive electrode current collector 11.

[0017] The power generating element 20 is formed by stacking and pressing a plurality of the above-described positive electrode current collectors 11, positive electrode layers 12, solid electrolyte layers 13, negative electrode layers 14, and negative electrode current collectors 15. For example, solid electrolyte layers 13 formed on SUS foil are placed on the top and bottom (±Z sides) of a positive electrode current collector 11 coated on both sides with a positive electrode layer 12, and isostatic pressing is performed under predetermined pressure and temperature conditions to transfer the solid electrolyte layer 13 to the positive electrode layer 12. This forms a laminate in which the solid electrolyte layer 13, positive electrode layer 12, positive electrode current collector 11, positive electrode layer 12, and solid electrolyte layer 13 are stacked in this order. Thereafter, anode current collectors 15 coated with anode layers 14 are placed on the top and bottom (±Z sides) of the laminate so that the anode layers 14 face the solid electrolyte layer 13, and isostatic pressing is performed under predetermined pressure and temperature conditions. By repeating the above steps, a power generating element 20 is formed, in which a plurality of stacks of the positive electrode current collector 11, the positive electrode layer 12, the solid electrolyte layer 13, the negative electrode layer 14, and the negative electrode current collector 15 are stacked.

[0018] Next, the insulating portion 16 will be described. As shown in FIG. 3 , the outer peripheral side surface 121 of the positive electrode layer 12, the outer peripheral side surface 131 of the solid electrolyte layer 13, and the outer peripheral side surface 141 of the negative electrode layer 14 are located inside the outer peripheral edges of the positive electrode current collector 11 and the negative electrode current collector 15. In other words, the positive electrode current collector 11 and the negative electrode current collector 15 extend in a direction away from the power generating element 20. The insulating portion 16 is provided between the positive electrode current collector 11 and the negative electrode current collector 15 to surround the positive electrode layer 12, the solid electrolyte layer 13, and the negative electrode layer 14 of the power generating element 20. As shown in FIG. 3 , the insulating portion 16 includes a first insulating portion 17 and a second insulating portion 18.

[0019] The first insulating portion 17 is provided on the positive electrode current collector 11, and when viewed from the Z direction, surrounds the positive electrode layer 12 and covers the outer peripheral side surface 121 of the positive electrode layer 12. The first insulating portion 17 is made of an insulating material having an electrical resistivity at least equivalent to that of the solid electrolyte layer 13, for example, a composite of insulating particles and a binder. The first insulating portion 17 may also be made of the same material as the solid electrolyte layer 13. In this case, the solid electrolyte layer 13 and the first insulating portion 17 may be formed simultaneously. That is, the first insulating portion 17 can be formed on SUS foil at the same time as the solid electrolyte layer 13, and then isostatically pressed to tightly bond the first insulating portion 17 to the positive electrode current collector 11 and the positive electrode layer 12 together with the solid electrolyte layer 13.

[0020] More specifically, the first insulating portion 17 includes a first portion 171 and a second portion 172. The first portion 171 is joined to the surface of the positive electrode current collector 11 (at least one of the +Z side surface and the −Z side surface) and to the positive electrode current collector 11 side of the outer peripheral side surface 121 of the positive electrode layer 12. The second portion 172 rises from the positive electrode layer 12 side of the first portion 171 along the outer peripheral side surface 121 of the positive electrode layer 12 and covers and is joined to the outer peripheral side surface 121 of the positive electrode layer 12. As described above, the end face 172B of the second portion 172 opposite to the positive electrode current collector 11 is configured to be flush with the end face 122 of the positive electrode layer 12 opposite to the positive electrode current collector 11. In this embodiment, as shown in FIG. 3 , the solid electrolyte layer 13 is provided so as to entirely cover the end face 122 of the positive electrode layer 12 and the end face 172B of the second portion 172.

[0021] In this embodiment, the width of the first portion 171 in a second direction perpendicular to the Z direction (first direction in the present disclosure) and away from the positive electrode layer 12 is defined as L Ｉ１ (the length from the outer peripheral side surface 171A of the first portion 171 to the outer peripheral side surface 121 of the positive electrode layer 12), and the width in a second direction perpendicular to the Z direction of the second portion 172 and away from the positive electrode layer 12 is L Ｉ２ (the length from the outer peripheral side surface 172A of the second portion 172 to the outer peripheral side surface 121 of the positive electrode layer 12), L Ｉ１ >L Ｉ２ For example, for the first insulating portion 17 disposed on the ±X side of the positive electrode layer 12, the second direction is the X direction, as shown in FIG. 3. On the other hand, for the first insulating portion 17 disposed on the ±Y side of the positive electrode layer 12, the second direction is the Y direction. As shown in FIG. 2, in this case as well, L Ｉ１ >L Ｉ２ This becomes:

[0022] In this embodiment, when viewed from the Z direction, the first insulating portion 17 is provided to surround the positive electrode layer 12 as shown in FIG. 2. Therefore, the width of the positive electrode layer 12 in the X direction is defined as L ＡＸ , the total width of the first part 171 of the first insulating part 17 in the X direction is L ＩＸ１ , the total width of the second portion 172 in the X direction is L ＩＸ２ Then, L ＡＸ <L ＩＸ２ <L ＩＸ１ The same applies to the width in the Y direction. The width of the positive electrode layer 12 in the Y direction is L ＡＹ , the total width of the first part 171 of the first insulating part 17 in the Y direction is L ＩＹ１ , the total width of the second portion 172 in the Y direction is L ＩＹ２ Then, L ＡＹ <L ＩＹ２ <L ＩＹ１ That is, when a direction perpendicular to the Z direction (first direction) and along the outer peripheral side surface 121 of the positive electrode layer 12 is defined as a third direction, the third direction is the Y direction with respect to the first insulating portion 17 disposed on the ±X side of the positive electrode layer 12, and the L ＡＹ <L ＩＹ２ <L ＩＹ１ Furthermore, with respect to the first insulating portion 17 disposed on the ±Y side of the positive electrode layer 12, the third direction is the X direction, and L ＡＸ <LＩＸ２ <L ＩＸ１ Meet the following.

[0023] The second insulating portion 18 is filled between the positive electrode current collector 11 and the negative electrode current collector 15 and is provided to cover the first insulating portion 17 and portions of the power generating element 20 that are not covered by the first insulating portion 17. For example, as shown in FIG. 3 , the second insulating portion 18 is bonded to the positive electrode current collector 11, the outer peripheral side surface 171A of the first portion 171 of the first insulating portion 17, the upper surface 171B of the first portion 171 opposite the positive electrode current collector 11, the outer peripheral side surface 172A of the second portion 172, the outer peripheral side surface 131 of the solid electrolyte layer 13, a portion of the end surface 132 of the solid electrolyte layer 13 where the negative electrode layer 14 is not provided, the outer peripheral side surface 141 of the negative electrode layer 14, and the negative electrode current collector 15. The second insulating portion 18 can be made of, for example, an insulating thermosetting resin. In this case, the second insulating portion 18 can be formed by filling the gaps in the power generating element 20 formed as described above with a liquid second insulating portion 18, vacuum degassing, and heating to harden the resin.

[0024] In this embodiment, as described above, the second insulating part 18 is in contact with multiple surfaces of the first insulating part 17. Therefore, compared to a case in which only the inner peripheral surface parallel to the Z direction of a rectangular cylindrical (frame-shaped) insulator is joined to the power-generating element 20, as shown in Patent Document 1, for example, the contact area with the first insulating part 17 and the power-generating element 20 is larger, resulting in higher bonding strength. Therefore, even when vibration, impact, pressure, or the like is applied to the solid-state battery 1, spaces are less likely to be generated between the first insulating part 17 and the second insulating part 18 and between the power-generating element 20 and the first insulating part 17.

[0025] [Effects of the Present Embodiment] The solid state battery 1 of the present embodiment includes a power generating element 20 including a stack of a positive electrode current collector 11, a positive electrode layer 12, a solid electrolyte layer 13, a negative electrode layer 14, and a negative electrode current collector 15. The positive electrode current collector 11 and the negative electrode current collector 15 extend in a direction away from the power generating element 20, and an insulating portion 16 is provided between the positive electrode current collector 11 and the negative electrode current collector 15 to surround the positive electrode layer 12, the solid electrolyte layer 13, and the negative electrode layer 14 of the power generating element 20. The insulating portion 16 includes a first insulating portion 17 and a second insulating portion 18. The first insulating portion 17 includes a first portion 171 that covers a surface (XY plane) of the positive electrode current collector 11 that is perpendicular to the Z direction, and a second portion 172 that rises from the first portion 171 in the Z direction and covers an outer peripheral side surface 121 of the positive electrode layer 12 that is aligned in the Z direction. The second insulating portion 18 is disposed between the positive electrode current collector 11 and the negative electrode current collector 15, and covers the surface of the power generating element 20 that is not covered by the first insulating portion 17, as well as the first insulating portion 17. The first insulating portion 17 has a width L Ｉ１ is the width L of the second portion 172 in the direction away from the positive electrode layer 12 Ｉ２ is greater than.

[0026] In this configuration, the contact area between the first insulating portion 17 and the second insulating portion 18 and the contact area between the first insulating portion 17 and the power-generating element 20 are larger than in the case of, for example, Patent Document 1, in which only the inner circumferential surface of the frame-shaped insulator parallel to the Z direction is bonded to the power-generating element. This increases the bonding strength between the first insulating portion 17 and the second insulating portion 18 and between the first insulating portion 17 and the power-generating element 20. Therefore, even if vibration or impact is applied, spaces are less likely to form between the first insulating portion 17 and the second insulating portion 18 or between the first insulating portion 17 and the power-generating element 20. Therefore, even if a confining pressure is applied to the solid-state battery 1, the solid electrolyte layer 13 is less likely to break, and short circuits due to breakage of the solid electrolyte layer 13 are less likely to occur. This reduces performance degradation of the solid-state battery 1.

[0027] In the solid-state battery 1 of this embodiment, the total width L of the second portion 172 of the first insulating portion 17 in the X direction ＩＸ２ is the width L of the positive electrode layer 12 in the X direction ＡＸ The overall width L of the second portion 172 in the Y direction is larger than ＩＹ２ is the width L of the positive electrode layer 12 in the Y direction ＡＹTherefore, when the second portion 172 protrudes outward from the positive electrode layer 12, the contact area between the second portion 172 of the first insulating portion 17 and the second insulating portion 18 increases, and the bonding strength can be increased.

[0028] In the solid-state battery 1 of this embodiment, the overall width L in the X direction of the first part 171 of the first insulating part 17 ＩＸ１ is the width L of the positive electrode layer 12 in the X direction ＡＸ The total width L of the first portion 171 in the Y direction is larger than ＩＹ１ is the width L of the positive electrode layer 12 in the Y direction ＡＹ Therefore, the first portion 171 protrudes outward from the positive electrode layer 12, in particular, protrudes further than the second portion 172 surrounding the outer peripheral side surface 121 of the positive electrode layer 12, thereby increasing the contact area between the first portion 171 of the first insulating portion 17 and the second insulating portion 18 and increasing the bonding strength.

[0029] Second Embodiment Next, a second embodiment will be described. In the first embodiment, as shown in Fig. 3 , the solid electrolyte layer 13 is disposed so as to entirely cover the end face 122 of the positive electrode layer 12 and the end face 172B of the second portion 172 of the first insulating portion 17. In contrast, the second embodiment differs from the first embodiment in that the solid electrolyte layer 13 entirely covers the end face 122 of the positive electrode layer 12 and only a portion of the end face 172B of the second portion 172.

[0030] 4 is a cross-sectional view of the main battery portion 2 of the solid-state battery according to the second embodiment. In this embodiment, as shown in FIG. 4 , the solid electrolyte layer 13 is provided to cover an inner region 172C of the end face of the second portion 172 that surrounds the positive electrode layer 12 and the entire end face 122 of the positive electrode layer 12. Therefore, an outer region 172D of the end face of the second portion 172 is not in contact with the solid electrolyte layer 13 but is in contact with the second insulating portion 18.

[0031] [Effects of the Present Embodiment] In the solid-state battery of the present embodiment, the solid electrolyte layer 13 is laminated from the positive electrode layer 12 to a portion of the second portion 172 of the first insulating portion 17. The second insulating portion 18 is joined to an outer region 172D, which is a portion of the negative electrode-side end face of the second portion 172 where the solid electrolyte layer 13 is not laminated. That is, in the present embodiment, a step is formed between the outer region 172D of the second portion 172 and the outer peripheral side surface 131 of the solid electrolyte layer 13, and the second insulating portion 18 contacts the step so as to fill the step. Therefore, the contact area between the first insulating portion 17 and the second insulating portion 18 is increased compared to a case where no step is provided, and thus the bonding strength between the first insulating portion 17 and the second insulating portion 18 is also increased. Therefore, when the solid-state battery is subjected to vibration or impact, the generation of a space between the first insulating portion 17 and the second insulating portion 18 can be more effectively suppressed.

[0032] Third Embodiment Next, a third embodiment will be described. In the first embodiment, the outer peripheral side surface 171A of the first part 171 of the first insulating part 17 and the outer peripheral side surface 172A of the second part 172 are surfaces that are substantially aligned along the Z direction. However, this is not limiting. FIG. 5 is a cross-sectional view of a battery main part 2 in a solid-state battery according to the third embodiment. In the solid-state battery shown in FIG. 5, the outer peripheral side surface 171A of the first part 171 of the first insulating part 17 is an inclined surface that slopes toward the positive electrode current collector 11 as it becomes farther away from the positive electrode layer 12. Similarly, the outer peripheral side surface 172A of the second part 172 of the first insulating part 17 is an inclined surface that slopes toward the positive electrode current collector 11 as it becomes farther away from the positive electrode layer 12.

[0033] [Effects of the Present Embodiment] In the solid-state battery of the present embodiment, the outer peripheral side surface 172A of the second portion 172 of the first insulating portion 17 is an inclined surface that slopes toward the positive electrode current collector 11 with increasing distance from the positive electrode layer 12. Similarly, the outer peripheral side surface 171A of the first portion 171 of the first insulating portion 17 is an inclined surface that slopes toward the positive electrode current collector 11 with increasing distance from the positive electrode layer 12. As a result, in the present embodiment, the outer peripheral side surfaces 171A, 172A can disperse forces due to vibrations or impacts applied in the Z direction and in directions perpendicular to the Z direction. For example, similar to the first embodiment, the first insulating portion 17 is formed in a rectangular shape surrounding the positive electrode layer 12 in a plan view seen from the Z direction. The outer peripheral side surfaces 171A, 172A, which are parallel to the Y direction when viewed from the Z direction, disperse forces applied from the Z direction or the X direction in the Z direction and the X direction. Furthermore, the outer peripheral side surfaces 171A and 172A, which are parallel to the X direction when viewed from the Z direction, disperse the force applied from the Z direction or the Y direction into the Z direction and the Y direction, thereby suppressing peeling between the first insulating portion 17 and the second insulating portion 18 due to vibration or impact.

[0034] [Fourth Embodiment] Next, a fourth embodiment will be described. In this embodiment, the surface structure of the first insulating portion 17 is different from that of the solid-state battery 1 of the first embodiment. FIG. 6 is a cross-sectional view of a battery main portion 2 of a solid-state battery of the fourth embodiment. In this embodiment, at least the upper surface 171B of the first portion 171 of the first insulating portion 17 opposite the positive electrode current collector 11 is formed as an uneven surface. To form the uneven surface, for example, a constituent material of the first insulating portion 17 may be selected so as to increase the porosity of the first insulating portion 17. After the first insulating portion 17 is formed, the upper surface 171B may be processed into an uneven surface by performing a surface treatment such as blasting. Alternatively, after the first insulating portion 17 is formed, a processing treatment such as etching may be performed to process the upper surface 171B into an uneven surface.

[0035] [Effects of the Present Embodiment] In the solid-state battery of the present embodiment, at least the surface of the first insulating portion 17 that is bonded to the second insulating portion 18, for example, the upper surface 171B of the first portion 171, is an uneven surface. In such a solid-state battery of the present embodiment, the contact area between the upper surface 171B of the first insulating portion 17 and the second insulating portion 18 is increased, thereby improving the bonding strength between the first insulating portion 17 and the second insulating portion 18. Therefore, even when vibration or impact is applied to the solid-state battery, peeling between the first insulating portion 17 and the second insulating portion 18 can be suppressed, and the inconvenience of a space being formed between the first insulating portion 17 and the second insulating portion 18 can be suppressed.

[0036] Fifth Embodiment Next, a fifth embodiment will be described. In the first embodiment, as shown in Fig. 3 , the second insulating portion 18 is joined to the solid electrolyte layer 13, the negative electrode layer 14, and the first insulating portion 17 in surface contact with them. However, the present invention is not limited to this. The second insulating portion 18 may be joined to the solid electrolyte layer 13, the negative electrode layer 14, and the first insulating portion 17 by penetrating into a portion of the surface thereof.

[0037] FIG. 7 is a cross-sectional view of the battery main portion 2 of a solid-state battery according to a fifth embodiment. As described above, the second insulating portion 18 of this embodiment is made of, for example, an insulating thermosetting resin material. When using such a second insulating portion 18, a liquid resin material is filled between the positive electrode current collector 11 and the negative electrode current collector 15, penetrates the first insulating portion 17, the solid electrolyte layer 13, and the negative electrode layer 14, and is then cured by a heating process. As described above, the first insulating portion 17 and the solid electrolyte layer 13 can be made of the same material, for example, a mixture of a sulfide solid electrolyte (insulating particles) and a binder. In this case, the porosity of the first insulating portion 17 and the solid electrolyte layer 13 increases, allowing the liquid second insulating portion 18 to penetrate the first insulating portion 17 and the solid electrolyte layer 13. In FIG. 7, the penetrated portions 13A and 17A of the second insulating portion 18 into the first insulating portion 17 and the solid electrolyte layer 13 are indicated by dark shaded areas.

[0038] The same applies to the negative electrode layer 14. As described above, the negative electrode layer 14 is formed by mixing carbon black and a conductive metal as negative electrode active materials, a binder, and NMP, and has a high porosity. Therefore, the porosity of the negative electrode layer 14 is increased, and the liquid second insulating portion 18 permeates into the negative electrode layer 14. In Figure 7, the permeation portion 14A of the second insulating portion 18 into the negative electrode layer 14 is indicated by a dark shaded area.

[0039] Furthermore, in this embodiment, the anode layer 14 has a larger porosity than the solid electrolyte layer 13 and the first insulating portion 17. Therefore, the penetration depth W1 of the second insulating portion 18 into the anode layer 14 is larger than the penetration depth W2 of the second insulating portion 18 into the solid electrolyte layer 13 and the first insulating portion 17. Here, the penetration depth W1 refers to the length from the outer peripheral side surface 141 of the anode layer 14 to which the second insulating portion 18 has penetrated. Similarly, the penetration depth W2 refers to the length from the outer peripheral side surface 131 of the solid electrolyte layer 13 to which the second insulating portion 18 has penetrated, and the length from the surface of the first insulating portion 17 (the outer peripheral side surface 171A of the first portion 171, the upper surface 171B of the first portion 171, and the outer peripheral side surface 172A of the second portion 172). In general, the anode layer 14 has a smaller thickness in the Z direction than the cathode layer 12 and the solid electrolyte layer 13. Therefore, the contact area of ​​second insulating portion 18 with negative electrode layer 14 is smaller than the contact area of ​​second insulating portion 18 with other components. However, in the present embodiment, as described above, by making the penetration depth W1 of second insulating portion 18 into negative electrode layer 14 larger than the penetration depth W2 of second insulating portion 18 into first insulating portion 17 and solid electrolyte layer 13, it is possible to increase the bonding strength.

[0040] In this embodiment, similarly to the first embodiment, the solid electrolyte layer 13 is configured to cover the entire end face 122 of the positive electrode layer 12 and the end face 172B of the second portion 172 of the first insulating portion 17, but as in the second embodiment, it may be configured to cover the end face 122 of the positive electrode layer 12 and the outer region 172D of the end face of the second portion 172. In this case, the second insulating portion 18 is configured to penetrate from the outer region 172D of the end face of the second portion 172 by a penetration depth W2.

[0041] [Effects of the Present Embodiment] In the solid state battery of the present embodiment, the solid electrolyte layer 13 and the first insulating portion 17 are made of a composite of insulating particles and a binder, which forms voids in the first insulating portion 17 and allows the second insulating portion 18 to penetrate into the voids, thereby firmly bonding the solid electrolyte layer 13 and the second insulating portion 18, and thereby firmly bonding the first insulating portion 17 and the second insulating portion 18.

[0042] The negative electrode layer 14 is also made of a composite of a conductive metal, carbon, and a binder, which creates voids in the negative electrode layer 14, allowing the second insulating portion 18 to penetrate into the voids, thereby firmly bonding the negative electrode layer 14 and the second insulating portion 18 together.

[0043] The porosity of the anode layer 14 is greater than the porosity of the solid electrolyte layer 13 and the first insulating portion 17. As a result, the penetration depth W1 of the second insulating portion 18 in the anode layer 14 is greater than the penetration depth W2 of the second insulating portion 18 in the solid electrolyte layer 13 and the first insulating portion 17. Therefore, even if the anode layer 14 has a smaller thickness in the Z direction than the solid electrolyte layer 13 and the positive electrode layer 12, the bonding strength between the anode layer 14 and the second insulating portion 18 can be increased, and peeling due to vibration or impact can be suppressed.

[0044] [Modifications] The present invention is not limited to the above-described embodiment, and includes the following modifications within the scope of achieving the object of the present invention.

[0045] [Modification 1] In the third embodiment, the first insulating portion 17 has been illustrated as having both the outer peripheral side surface 171A of the first portion 171 and the outer peripheral side surface 172A of the second portion 172 as inclined surfaces, but is not limited thereto. For example, only one of the outer peripheral side surface 171A of the first portion 171 and the outer peripheral side surface 172A of the second portion 172 may be an inclined surface.

[0046] [Variation 2] In the fourth embodiment, an example was shown in which the upper surface 171B of the first part 171 of the first insulating part 17 is an uneven surface, but this is not limited to this. By providing an uneven surface on the surface of the first insulating part 17 that contacts the second insulating part 18, the bonding strength with the second insulating part 18 can be improved. For example, an uneven surface may also be provided on the outer peripheral side surface 171A of the first part 171 and the outer peripheral side surface 172A of the second part 172. Furthermore, a configuration in which the outer peripheral side surface 131 of the solid electrolyte layer 13 is an uneven surface or a configuration in which the outer peripheral side surface 141 of the negative electrode layer 14 is an uneven surface may also be used.

[0047] [Variation 3] In the fifth embodiment, an example was shown in which the porosities of the solid electrolyte layer 13, the first insulating portion 17, and the anode layer 14 are set so that the penetration depth W1 of the second insulating portion 18 in the anode layer 14 is larger than the penetration depth W2 of the second insulating portion 18 in the first insulating portion 17 and the solid electrolyte layer 13. However, the present invention is not limited to this. In other words, as long as the second insulating portion 18 penetrates into the anode layer 14 to an extent that sufficient bonding strength is obtained between the anode layer 14 and the second insulating portion 18, a configuration in which W1 < W2 may be used. In this case, the porosity of the anode layer 14 may be smaller than the porosity of the solid electrolyte layer 13 and the first insulating portion 17.

[0048] [Variation 4] The configuration of the first or second embodiment may be combined with the third to fifth embodiments. That is, the second insulating portion 18 may be joined to the solid electrolyte layer 13, the negative electrode layer 14, and the first insulating portion 17 by combining at least two of the following configurations: a configuration in which the outer peripheral side surfaces 171A, 172A of the first insulating portion 17 are inclined surfaces; a configuration in which the surface of the first insulating portion 17 that contacts the second insulating portion 18 is roughened to form an uneven surface; and a configuration in which the second insulating portion 18 is joined by penetrating the solid electrolyte layer 13, the negative electrode layer 14, and the first insulating portion 17. This allows the second insulating portion 18 to be joined to the first insulating portion 17 more firmly.

[0049] 1...Solid-state battery, 2...Battery main part, 3...Electrode tab, 3A...Positive electrode tab, 3B...Anode tab, 4...Sheathing material, 11...Positive electrode current collector, 12...Positive electrode layer, 13...Solid electrolyte layer, 13A...Portion of second insulating part permeated into solid electrolyte layer, 14...Anode layer, 14A...Portion of second insulating part permeated into negative electrode layer, 15...Anode current collector, 16...Insulating part, 17...First insulating part, 17A...Portion of second insulating part permeated into first insulating part, 18...Second insulating part, 20...Emitting part Electric element, 121...outer peripheral side surface of positive electrode layer, 122...end surface of positive electrode layer, 131...outer peripheral side surface of solid electrolyte layer, 132...end surface of solid electrolyte layer, 141...outer peripheral side surface of negative electrode layer, 171...first part, 171A...outer peripheral side surface of first part, 171B...top surface of first part, 172...second part, 172A...outer peripheral side surface of second part, 172B...end surface of second part, 172C...inner region at end surface of second part, 172D...outer region at end surface of second part.

Claims

1. A solid-state battery including a power generating element formed by stacking a positive electrode current collector, a positive electrode layer, a solid electrolyte layer containing a solid electrolyte, a negative electrode layer, and a negative electrode current collector in this order in a first direction, wherein the positive electrode current collector and the negative electrode current collector extend in a direction away from the power generating element, and an insulating part is disposed between the positive electrode current collector and the negative electrode current collector and surrounds the positive electrode layer, the solid electrolyte layer, and the negative electrode layer of the power generating element, the insulating part having: a first insulating part including a first part covering a surface of the positive electrode current collector perpendicular to the first direction, and a second part rising from the first part in the first direction and covering an outer peripheral side surface of the positive electrode layer along the first direction; and a second insulating part disposed between the positive electrode current collector and the negative electrode current collector and covering a surface of the power generating element not covered by the first insulating part and the first insulating part. a second direction is a direction orthogonal to the first direction and moving toward and away from the power-generating element, and the length in the second direction from a surface of the first part that contacts the positive electrode layer to an outer peripheral side surface of the first part is greater than the length in the second direction from a surface of the second part that contacts the positive electrode layer to an outer peripheral side surface of the second part.

2. The solid-state battery according to claim 1, wherein the second portion of the first insulating portion has an inclined surface that slopes toward the positive electrode current collector with increasing distance from the positive electrode layer.

3. The solid-state battery according to claim 1, wherein the solid electrolyte layer is laminated from the positive electrode layer to a portion of the second section, and the second insulating section is joined to a portion of the end face of the second section facing the negative electrode layer where the solid electrolyte layer is not laminated.

4. The solid-state battery according to claim 1, wherein a direction perpendicular to the first direction and along the outer peripheral side surface of the positive electrode layer is defined as a third direction, and the width of the second portion in the third direction is greater than the width of the positive electrode layer in the third direction.

5. The solid-state battery according to claim 1, wherein a direction perpendicular to the first direction and along the outer peripheral side surface of the positive electrode layer is defined as a third direction, and the width of the portion in the third direction is greater than the width of the positive electrode layer in the third direction.

6. The solid-state battery according to claim 1, wherein the outer periphery of the portion of the first insulating section is provided with an inclined surface that slopes toward the positive electrode current collector with increasing distance from the positive electrode layer.

7. The solid-state battery according to claim 1, wherein at least the surface of the first insulating part that is bonded to the second insulating part is an uneven surface.

8. The solid-state battery according to claim 1, wherein the first insulating portion is composed of a composite of insulating particles and a binder.

9. The solid-state battery according to claim 1, wherein the negative electrode layer is composed of a composite of a conductive metal, carbon, and a binder.

10. The solid-state battery according to claim 1, wherein the porosity of the negative electrode layer is greater than the porosity of the solid electrolyte layer and the porosity of the first insulating portion.

Images