Solid-state battery and method for manufacturing a solid-state battery

Abstract

To realize high-quality solid-state batteries. [Solution] The solid-state battery includes an electrolyte layer and a positive electrode layer or a negative electrode layer provided on one side thereof. As the positive electrode layer or negative electrode layer, an electrode layer 80 including a linear portion 81 and a coating layer 82 is used. At least one linear portion 81 is provided on one side of the electrolyte layer so as to extend along that surface. The coating layer 82 is provided so as to cover the side of the electrolyte layer on which the linear portion 81 is provided. The linear portion 81 and the coating layer 82 contain a positive electrode active material if the electrode layer 80 is a positive electrode layer, and a negative electrode active material if the electrode layer 80 is a negative electrode layer. Surface irregularities caused by the saddle phenomenon are suppressed and an electrode layer 80 with sufficient uniformity in film thickness is obtained.

Description

Technical Field

[0001] The present invention relates to a solid battery and a method for manufacturing the same.

Background Art

[0002] There is known a solid battery provided with an electrode in which columnar bodies of an electrode active material in contact with a current collector and columnar bodies of an electrode solid electrolyte in contact with a separator are alternately adjacent to each other and arranged in a direction intersecting the plane of the separator between the separator of the solid electrolyte and the current collector (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there is known a solid battery having a configuration in which an electrode layer of a positive electrode or a negative electrode is provided on an electrolyte layer with a predetermined film thickness. In such a solid battery, if the uniformity of the film thickness of the electrode layer provided on the electrolyte layer is not sufficient, there are cases where high-quality solid batteries cannot be obtained, such as a decrease in battery performance.

[0005] On one aspect, an object of the present invention is to realize a high-quality solid battery.

Means for Solving the Problems

[0007] In another embodiment, a method for manufacturing a solid-state battery as described above is provided. [Effects of the Invention]

[0008] On one hand, this makes it possible to create high-quality solid-state batteries. [Brief explanation of the drawing]

[0009] [Figure 1] This is a diagram illustrating an example of a solid-state battery. [Figure 2] This diagram illustrates an example of the configuration of layer components in a solid-state battery. [Figure 3] This figure illustrates an example of electrode layer formation using the screen printing method. [Figure 4] This figure illustrates an example of a method for forming an electrode layer according to the first embodiment. [Figure 5] This figure illustrates an example of an electrode layer according to the first embodiment. [Figure 6] This figure illustrates an example of the configuration of an electrode layer according to the first embodiment. [Figure 7] This figure illustrates an example of a method for forming an electrode layer according to the second embodiment. [Figure 8] This figure illustrates an example of an electrode layer according to the second embodiment. [Figure 9] This figure illustrates a first example of the arrangement of electrode layers in a solid-state battery according to the third embodiment. [Figure 10] This figure illustrates a second example of the arrangement of the electrode layers of a solid-state battery according to the third embodiment. [Modes for carrying out the invention]

[0010] Figure 1 illustrates an example of a solid-state battery. Figure 1(A) schematically shows a perspective view of the main parts of an example solid-state battery. Figures 1(B) and 1(C) schematically show cross-sectional views of the main parts of an example solid-state battery, respectively. Figure 1(B) is a schematic cross-sectional view taken along line L1 in Figure 1(A). Figure 1(C) is a schematic cross-sectional view taken along line L2 in Figure 1(A).

[0011] The solid-state battery 1 shown in Figures 1(A) to 1(C) is an example of a lithium-ion battery. The solid-state battery 1 includes a battery body 10, external connection terminals 20 and 30. As shown in Figures 1(B) and 1(C), the battery body 10 includes a power generation element 14 inside, which has an electrode layer, a positive electrode layer 11 and a negative electrode layer 12, and an electrolyte layer 13 provided at least between them. The positive electrode layer 11, negative electrode layer 12 and electrolyte layer 13 of the power generation element 14 are stacked in a predetermined order in a first direction D1. The positive electrode layer 11 and the negative electrode layer 12 are stacked in the first direction D1 such that they partially overlap via the electrolyte layer 13.

[0012] For convenience, we will use a solid-state battery 1 containing two positive electrode layers 11 and two negative electrode layers 12 as an example. However, the number of positive electrode layers 11 and negative electrode layers 12 is not limited to this example, as long as the positive electrode layers 11 and negative electrode layers 12 are stacked in the first direction D1 via an electrolyte layer 13. Furthermore, the bottom and top layers of the power generation element 14 may be the positive electrode layer 11, the negative electrode layer 12, or the electrolyte layer 13, respectively.

[0013] The battery body 10 further includes an insulating cover layer 15 that covers a predetermined portion of the power generation element 14. As shown in FIGS. 1(B) and 1(C), the cover layer 15 covers the upper and lower surfaces of the power generation element 14 that face both sides in the first direction D1, respectively. As shown in FIG. 1(B), the cover layer 15 further covers the end surface of the positive electrode layer 11 facing one side in the second direction D2 orthogonal to the first direction D1 (and the third direction D3) of the power generation element 14 and the end surface of the negative electrode layer 12 facing the other side in the second direction D2. As shown in FIG. 1(C), the cover layer 15 further covers the end surfaces of the positive electrode layer 11, the end surface of the negative electrode layer 12, and the end surface of the electrolyte layer 13 that face both sides in the third direction D3 orthogonal to the first direction D1 (and the second direction D2) of the power generation element 14. <00,00087> As shown in FIG. 1(B), the battery body 10 has a positive electrode lead-out surface 10a where the end surface of the positive electrode layer 11 is exposed and a negative electrode lead-out surface 10b where the end surface of the negative electrode layer 12 is exposed on both sides in the second direction D2, respectively. External connection terminals 20 and external connection terminals 30 are provided on the positive electrode lead-out surface 10a and the negative electrode lead-out surface 10b of the battery body 10, respectively. The external connection terminal 20 is connected to the end surface of the positive electrode layer 11 exposed on the positive electrode lead-out surface 10a and functions as the positive electrode terminal of the solid-state battery 1. The external connection terminal 30 is connected to the end surface of the negative electrode layer 12 exposed on the negative electrode lead-out surface 10b and functions as the negative electrode terminal of the solid-state battery 1.

[0015] Incidentally, one or both of the positive electrode layer 11 and the negative electrode layer 12 are also referred to as "electrode layers". One of the positive electrode layer 11 and the negative electrode layer 12 is also referred to as the "first electrode layer", and the other is also referred to as the "second electrode layer". Also, one of the one electrolyte layer 13 adjacent to the positive electrode layer 11 and the other electrolyte layer 13 adjacent to the negative electrode layer 12 is also referred to as the "first electrolyte layer", and the other is also referred to as the "second electrolyte layer".

[0016] Here, the power generation element 14, the cover layer 15, the external connection terminal 20, and the external connection terminal 30 of the solid-state battery 1 having the above configuration will be further described. The electrolyte layer 13 of the power generation element 14 contains a solid electrolyte. For the solid electrolyte of the electrolyte layer 13, for example, an oxide solid electrolyte is used. As the oxide solid electrolyte of the electrolyte layer 13, for example, LAGP, which is one type of NASICON (Na super ionic conductor) type (also referred to as "NASICON type") oxide solid electrolyte, is used. LAGP is an oxide solid electrolyte represented by the general formula Li 1+x Al x Ge 2-x (PO4)3 (0 < x ≤ 1). In addition, a sulfide solid electrolyte such as Li2S (lithium sulfide)-P2S5 (diphosphorus pentasulfide) may be used as the solid electrolyte of the electrolyte layer 13.

[0017] The positive electrode layer 11 of the power generation element 14 contains a positive electrode active material, a conductive assistant, and a solid electrolyte. For the solid electrolyte of the positive electrode layer 11, an oxide solid electrolyte or a sulfide solid electrolyte, for example, the same kind of material as the solid electrolyte used in the electrolyte layer 13, is used. For the positive electrode active material of the positive electrode layer 11, for example, Li2CoP2O7 (lithium cobalt pyrophosphate, also referred to as "LCPO") etc. are used. For the conductive assistant of the positive electrode layer 11, for example, carbon materials such as carbon fiber, carbon black, graphite, graphene, carbon nanotubes, and conductive materials such as iron silicide are used.

[0018] The negative electrode layer 12 of the power generation element 14 contains a negative electrode active material, a conductive assistant, and a solid electrolyte. For the solid electrolyte of the negative electrode layer 12, an oxide solid electrolyte or a sulfide solid electrolyte, for example, the same kind of material as the solid electrolyte used in the electrolyte layer 13, is used. For the negative electrode active material of the negative electrode layer 12, for example, TiO2 (titanium oxide), Nb2O5 (niobium pentoxide) etc. are used. In addition, Li3V2(PO4)3 (lithium vanadium phosphate), Li4Ti5O 12 (lithium titanate) etc. may be used as the negative electrode active material of the negative electrode layer 12. For the conductive assistant of the negative electrode layer 12, for example, carbon materials such as carbon fiber, carbon black, graphite, graphene, carbon nanotubes, and conductive materials such as iron silicide are used.

[0019] In the solid-state battery 1, during charging, lithium ions are conducted from the positive electrode layer 11 to the negative electrode layer 12 via the electrolyte layer 13 and taken up, and during discharging, lithium ions are conducted from the negative electrode layer 12 to the positive electrode layer 11 via the electrolyte layer 13 and taken up. In the solid-state battery 1, charging and discharging operations are realized by this lithium ion conduction.

[0020] Various insulating materials with insulating properties are used for the cover layer 15. The insulating properties of the insulating material used in the cover layer 15 refer to properties that have no or sufficiently low influence on lithium ion conduction and electron conduction in the power generation element 14. For example, the cover layer 15 uses an insulating material with a lower electron conductivity than the positive electrode layer 11 and the negative electrode layer 12. It is preferable that the cover layer 15 be made of a material with low permeability to moisture and gases and good sealing properties. In particular, it is preferable to use a material for the cover layer 15 that has a coefficient of linear expansion similar to that of each layer constituting the power generation element 14, or that has good adhesion to each of those layers. As the insulating material for the cover layer 15, glass, ceramics, solid electrolytes, etc., can be used.

[0021] External connection terminals 20 are connected to the end face of the positive electrode layer 11 exposed from the cover layer 15 on the positive electrode lead surface 10a of the battery body 10. External connection terminals 30 are connected to the end face of the negative electrode layer 12 exposed from the cover layer 15 on the negative electrode lead surface 10b of the battery body 10. External connection terminals 20 and 30 are formed by applying a paste containing conductive components, such as metallic materials like Ag (silver), Cu (copper), and Ni (nickel), or carbon materials like carbon fiber and carbon particles, to the positive electrode lead surface 10a and negative electrode lead surface 10b, respectively, and then performing heat treatment such as drying, hardening, or baking. External connection terminals 20 and 30 may also be formed by depositing various metallic materials such as Ni and Sn (tin) on the positive electrode lead surface 10a and negative electrode lead surface 10b, or on the surface of the layer formed by the application of the paste and heat treatment, using sputtering or plating methods.

[0022] Next, the manufacturing method of the solid-state battery 1 will be explained with reference to Figure 2 below and Figure 1 above. Figure 2 illustrates an example of the configuration of layer components in a solid-state battery. Figures 2(A) to 2(E) schematically show perspective views of the main parts of an example of layer components.

[0023] In the manufacturing of the solid-state battery 1 described above, for example, each layer component as shown in Figures 2(A) to 2(E) is formed. For the formation of each layer component, pastes for the electrolyte layer 13, the positive electrode layer 11, the negative electrode layer 12, and the cover layer 15 are prepared, respectively. For the positive electrode layer 11, a paste containing a positive electrode active material, a solid electrolyte, a conductive additive, a binder, a plasticizer, a dispersant, and a diluent is prepared. For the negative electrode layer 12, a paste containing a negative electrode active material, a solid electrolyte, a conductive additive, a binder, a plasticizer, a dispersant, and a diluent is prepared. For the electrolyte layer 13, a paste containing a solid electrolyte, as well as a binder, a plasticizer, a dispersant, and a diluent is prepared. For the cover layer 15, for example, a paste containing glass or ceramic or a solid electrolyte, as well as a binder, a plasticizer, a dispersant, and a diluent is prepared.

[0024] The paste for the cover layer 15 is applied to a support such as a polyethylene terephthalate (PET) film using a printing method or the like, to form a layer part 40 having the configuration shown in Figure 2(A), i.e., a layer part 40 that will become the cover layer 15.

[0025] The paste for the positive electrode layer 11 and the paste for the cover layer 15 provided on the outside are applied to a support using a printing method or the like, forming a layer part 41 having the configuration shown in Figure 2(B), that is, a layer part 41 including the positive electrode layer 11 and the cover layer 15 on its outside.

[0026] The paste for the electrolyte layer 13 and the paste for the cover layer 15 provided on the outside are applied to the support using a printing method or the like, forming a layer part 42 having the configuration shown in Figure 2(C), that is, a layer part 42 including the electrolyte layer 13 and the cover layer 15 on the outside.

[0027] The paste for the negative electrode layer 12 and the paste for the cover layer 15 provided on the outside are applied to the support using a printing method or the like, forming a layer part 43 having the configuration shown in Figure 2(D), that is, a layer part 43 including the negative electrode layer 12 and the cover layer 15 on the outside.

[0028] The paste for the electrolyte layer 13 and the paste for the cover layer 15 provided on the outside are applied to a support using a printing method or the like, forming a layer part 44 having the configuration shown in Figure 2(E), that is, a layer part 44 including the electrolyte layer 13 and the cover layer 15 on the outside.

[0029] Furthermore, the layer part 41 (Figure 2(B)), which includes the positive electrode layer 11 and the outer cover layer 15, may be formed using a PET film as a support. Alternatively, the layer part 41 (Figure 2(B)) may be formed by using a layer part 42 (Figure 2(C)), which includes the electrolyte layer 13 and the outer cover layer 15, as a support, and applying a paste for the positive electrode layer 11 and a paste for the outer cover layer 15 on top of it.

[0030] Furthermore, the layer part 43 (Figure 2(D)), which includes the negative electrode layer 12 and the outer cover layer 15, may be formed using a PET film as a support. Alternatively, the layer part 43 (Figure 2(D)) may be formed by using a layer part 44 (Figure 2(E)), which includes the electrolyte layer 13 and the outer cover layer 15, as a support, and applying a paste for the negative electrode layer 12 and a paste for the outer cover layer 15 on top of it.

[0031] The formed layer parts 40-44 are stacked in a first direction D1 in a predetermined stacking order as shown in Figures 1(B) and 1(C), and are thermocompressed under predetermined temperature and pressure conditions. This forms a battery body 10 comprising a power generation element 14 including a positive electrode layer 11, a negative electrode layer 12, and an electrolyte layer 13, and a cover layer 15 that covers a predetermined part of it.

[0032] Figure 1(B) schematically shows the cross-section corresponding to the position of the center line C1 along the second direction D2 when the layer parts 40-44 shown in Figures 2(A) to 2(E) are stacked in the first direction D1 in a predetermined stacking order with their respective center lines C1 and C2 aligned. Figure 1(C) schematically shows the cross-section corresponding to the position of the center line C2 along the third direction D3 when the layer parts 40-44 shown in Figures 2(A) to 2(E) are stacked in the first direction D1 in a predetermined stacking order with their respective center lines C1 and C2 aligned.

[0033] The battery body 10 may be cut after lamination and heat-sealing as described above to obtain the structure shown in Figures 1(B) and 1(C). In this case, cutting after lamination and heat-sealing may result in a structure having a positive electrode lead surface 10a where one end surface of the positive electrode layer 11 is exposed and a negative electrode lead surface 10b where one end surface of the negative electrode layer 12 is exposed, as shown in Figure 1(B). At this time, the layer parts 41-44 are not limited to the forms shown in Figures 2(B) to 2(E), but may also be in a form in which a cover layer 15 is provided so as to surround the entire outer circumference of each of the positive electrode layer 11, electrolyte layer 13, and negative electrode layer 12, and when they are cut after lamination and heat-sealing, they may be formed into a structure as shown in Figure 1(B), that is, a structure having a positive electrode lead surface 10a where one end surface of the positive electrode layer 11 is exposed and a negative electrode lead surface 10b where one end surface of the negative electrode layer 12 is exposed.

[0034] After lamination and heat-compression bonding (and further cutting if cutting is performed), the battery body 10 is degreased of organic components such as binders by heat treatment under predetermined conditions, and further fired by heat treatment under predetermined conditions to burn off solid electrolytes and other components contained inside. As a result, a battery body 10 having the configuration shown in Figures 1(B) and 1(C) above is manufactured.

[0035] External connection terminals 20 and 30 are formed on the positive electrode lead surface 10a and the negative electrode lead surface 10b of the battery body 10, respectively, as shown in Figures 1(A) and 1(B). For example, the external connection terminals 20 and 30 are formed by applying a paste containing a conductive material such as Ag to the positive electrode lead surface 10a and the negative electrode lead surface 10b of the battery body 10, baking or hardening them by heat treatment under predetermined conditions, and then plating the surface with Ni and Sn.

[0036] Through the process described above, a solid-state battery 1 having the configuration shown in Figures 1(A), 1(B), and 1(C) is manufactured. Here, we will further describe the formation of the positive electrode layer 11 and the negative electrode layer 12 used as electrode layers for the solid-state battery 1.

[0037] Electrode layers such as the positive electrode layer 11 and the negative electrode layer 12 are formed, for example, using a screen printing method. Figure 3 illustrates an example of electrode layer formation using screen printing. Figure 3(A) schematically shows a cross-sectional view of the main parts of an example of the support and screen preparation process. Figure 3(B) schematically shows a cross-sectional view of the main parts of an example of the electrode layer printing process. Figure 3(C) schematically shows a cross-sectional view of the main parts of an example of the screen removal process, specifically an example of an electrode layer screen-printed on a support. Figure 3(D) schematically shows a plan view of the main parts of an example of an electrode layer screen-printed on a support.

[0038] First, a support 50 and a screen 60 are prepared as shown in Figure 3(A). The support 50 can be a PET film as described above, or a predetermined layer part (the electrolyte layer 13 of layer part 42 when a positive electrode layer 11 is formed on it, or the electrolyte layer 13 of layer part 44 when a negative electrode layer 12 is formed on it).

[0039] After the support 50 and screen 60 are prepared, the screen 60 is placed on the surface 50a of the support 50, which is the printing surface, as shown in Figure 3(B). Then, as shown in Figure 3(B), the printed material 100a, which will become the electrode layer 100 as described later and will be used as the positive electrode layer 11 or the negative electrode layer 12, i.e., the paste for the electrode layer 100, is applied to the surface 50a of the support 50 through the screen 60 using the squeegee 70.

[0040] Subsequently, as shown in Figure 3(C), the screen 60 is removed. As a result, as shown in Figures 3(C) and 3(D), the printed material 100a is printed on the area on the surface 50a of the support 50 corresponding to the screen 60. This printed material 100a forms an electrode layer 100 which is used as the positive electrode layer 11 or the negative electrode layer 12.

[0041] When an electrode layer 100 (printed material 100a) is formed using such a screen printing method, the formed electrode layer 100 may have a thicker outer film than the inner film due to the so-called saddle effect, as shown in Figures 3(C) and 3(D). That is, the electrode layer 100 formed using the screen printing method may have a relatively thin inner recess 101 and a relatively thick outer convex portion 102. Note that in Figure 3(D), the boundary between the recess 101 and the convex portion 102 of the electrode layer 100 is shown schematically for the sake of explanation and is not necessarily limited to the illustrated position.

[0042] For example, an electrode layer 100 having such a recess 101 and a protrusion 102 is used as a positive electrode layer 11 or a negative electrode layer 12, and a layer part (layer part 41 or 43) containing it is formed according to the example of the manufacturing method described above, and this is stacked with other layer parts (layer parts 42 and 44) ​​to manufacture a solid-state battery 1. However, the following may occur in a solid-state battery 1 manufactured in this way.

[0043] In other words, when an electrode layer 100 having recesses 101 and protrusions 102 and lacking sufficient uniformity of film thickness is formed as the positive electrode layer 11 or the negative electrode layer 12, an in-plane distribution occurs in the amount of active material, i.e., the amount of positive electrode active material or the amount of negative electrode active material. That is, the amount of active material contained in the recesses 101, which have a relatively thin film thickness, is relatively small, and the amount of active material contained in the protrusions 102, which have a relatively thick film thickness, is relatively large. If the uniformity of the amount of active material is insufficient in this way, during the charging and discharging operation of the solid-state battery 1 which includes the electrode layer 100 as the positive electrode layer 11 or the negative electrode layer 12, variations occur in the in-plane utilization rate of the electrode layer 100, which may lead to locally accelerated deterioration of the recesses 101, potentially resulting in a decrease in the battery performance and lifespan of the solid-state battery 1.

[0044] In addition, for example, when the solid-state battery 1 is charged, lithium ions are taken in from the positive electrode layer 11 to the negative electrode layer 12, causing the negative electrode layer 12 to expand. If an electrode layer 100 having recesses 101 and protrusions 102 is formed as such a negative electrode layer 12, insufficient uniformity of its film thickness and active material content can cause an in-plane distribution in the amount of expansion, potentially leading to cracks or rupture of the solid-state battery 1.

[0045] Furthermore, in a solid-state battery 1 in which the stacked layer parts include one or more layers of layer parts 41 or layer parts 43 that contain an electrode layer 100 as a positive electrode layer 11 or a negative electrode layer 12, there is a risk that its shape stability will decrease. Specifically, the height difference caused by the recesses 101 and protrusions 102 of the electrode layer 100 contained inside the battery body 10 as a positive electrode layer 11 or a negative electrode layer 12 may accumulate, build up, or remain on the outer surface (upper and lower surfaces) of the battery body 10 as a result of the stacking of the electrode layer 100, which may reduce the flatness of the outer surface of the solid-state battery 1 and reduce its shape stability.

[0046] Thus, in a solid-state battery 1, if the thickness of the positive electrode layer 11 and the negative electrode layer 12 is not sufficiently uniform, it may result in a decrease in battery performance, a reduction in lifespan, the occurrence of cracks and ruptures, and a decrease in shape stability, making it impossible to obtain a high-quality solid-state battery 1.

[0047] Therefore, by adopting the configuration shown below as an embodiment, we realize an electrode layer with excellent uniformity of film thickness, and a high-quality solid-state battery 1 equipped with such an electrode layer. [First Embodiment] Figure 4 illustrates an example of an electrode layer formation method according to the first embodiment. Figure 4(A) schematically shows a plan view of the main part of an example of the linear part formation process. Figure 4(B) schematically shows a plan view of the main part of an example of the coating layer formation process. Figure 5 also illustrates an example of an electrode layer according to the first embodiment. Figure 5 schematically shows a cross-sectional view of the main part of an example of an electrode layer. Figure 5 is a schematic cross-sectional view of the VV section of Figure 4(B).

[0048] First, as shown in Figure 4(A), at least one linear portion 81 extending along the surface 50a is formed on the surface 50a of the support 50 using a screen printing method. Here, as an example, a configuration is shown in which four linear portions 81 extending parallel in a second direction D2 are formed side by side in a third direction D3. The support 50 on which the linear portions 81 are formed can be a PET film as described above, or a predetermined layer part (the electrolyte layer 13 of layer part 42 when a positive electrode layer 11 is formed on it, or the electrolyte layer 13 of layer part 44 when a negative electrode layer 12 is formed on it).

[0049] To form the linear portion 81, an electrode layer paste for electrode layers 80, specifically a paste for positive electrode layer 11 or negative electrode layer 12, is used to form an electrode layer 80 that includes the linear portion 81 and is used as a positive electrode layer 11 or a negative electrode layer 12, as described later.

[0050] Following the example of the screen printing method described above, a predetermined screen corresponding to the linear portion 81 to be formed is placed on the surface 50a of the support 50, and a predetermined paste for the electrode layer 80 is applied to the surface 50a of the support 50 through the screen using a squeegee. After that, the screen is removed. For example, the applied paste for the electrode layer 80 may be heat-treated in a predetermined atmosphere under predetermined temperature and time conditions, and dried. In this way, linear portions 81, such as those shown in Figure 4(A), or four parallel linear portions 81, are formed on the surface 50a of the support 50.

[0051] The formed linear portion 81 contains an active material. When the paste for the positive electrode layer 11 is used as the paste for the electrode layer 80 during screen printing of the linear portion 81, the formed linear portion 81 contains a positive electrode active material. When the paste for the negative electrode layer 12 is used as the paste for the electrode layer 80 during screen printing of the linear portion 81, the formed linear portion 81 contains a negative electrode active material.

[0052] After the linear portion 81 is formed, a covering layer 82 is formed to cover the linear portion 81 provided on the surface 50a of the support 50, as shown in Figure 4(B). Here, as an example, a covering layer 82 is formed to cover four parallel linear portions 81.

[0053] For forming the coating layer 82, an electrode layer paste for electrode layers 80, specifically a paste for positive electrode layers 11 or negative electrode layers 12, is used to form an electrode layer 80 that includes the linear portion 81 and the coating layer 82, as described later, and is used as either a positive electrode layer 11 or a negative electrode layer 12. Here, if the paste for positive electrode layers 11 is used to form the linear portion 81, the paste for positive electrode layers 11 is also used to form the coating layer 82. If the paste for negative electrode layers 12 is used to form the linear portion 81, the paste for negative electrode layers 12 is also used to form the coating layer 82.

[0054] Following the example of the screen printing method described above, a predetermined screen corresponding to the coating layer 82 to be formed is placed on the surface 50a of the support 50 on which the linear portions 81 are formed, and a predetermined paste for the electrode layer 80 is applied to the surface 50a of the support 50 through the screen using a squeegee. After that, the screen is removed. For example, the applied paste for the electrode layer 80 may be heat-treated in a predetermined atmosphere under predetermined temperature and time conditions, and dried. In this way, a coating layer 82, as shown in Figure 4(B), is formed on the surface 50a of the support 50 on which the linear portions 81 are formed, for example, a coating layer 82 that covers four parallel linear portions 81.

[0055] Furthermore, the heat treatment drying of the paste for the electrode layer 80 may be performed each time after coating to form the linear portion 81 and the coating layer 82, respectively, or it may be omitted after coating to form the linear portion 81 and performed all at once after coating to form the coating layer 82.

[0056] The formed coating layer 82 contains the same active material as the linear portion 81. When the paste for the positive electrode layer 11 is used as the paste for the electrode layer 80 during screen printing of the linear portion 81 and the subsequent coating layer 82, both the formed linear portion 81 and the formed coating layer 82 contain the positive electrode active material. When the paste for the negative electrode layer 12 is used as the paste for the electrode layer 80 during screen printing of the linear portion 81 and the subsequent coating layer 82, both the formed linear portion 81 and the formed coating layer 82 contain the negative electrode active material.

[0057] Figure 5 shows an example of a cross-sectional structure in which multiple linear portions 81 are formed on the surface 50a of the support 50, and a covering layer 82 is formed to cover them. Figure 5 is a schematic representation of the VV cross-section of Figure 4(B).

[0058] As shown in Figure 5, a plurality of linear portions 81 are formed side by side on the surface 50a of the support 50. Each formed linear portion 81 may have a curved surface 81a that bulges in an arc shape toward the opposite side of the support 50 when viewed in cross-section in a direction perpendicular to the direction in which it extends (the front or depth direction of the paper in Figure 5), as shown in Figure 5. Screen printing of the linear portions 81 may be performed so as to form such a curved surface 81a. Further, a coating layer 82 is formed on the surface 50a of the support 50 on which the plurality of linear portions 81 are formed, so as to cover the plurality of linear portions 81. The plurality of linear portions 81 and the coating layer 82 covering them form an electrode layer 80 that functions as the positive electrode layer 11 or the negative electrode layer 12 of the solid battery 1.

[0059] In an electrode layer 80 including such linear portions 81 and coating layers 82, the linear portions 81 suppress the occurrence of the saddle phenomenon when forming the coating layers 82. Therefore, the formation of irregularities on the surface of the electrode layer 80 due to the saddle phenomenon, or the formation of relatively large irregularities, is suppressed. As a result, an electrode layer 80 with sufficient uniformity in film thickness is realized.

[0060] As an example, in the electrode layer 100 formed by screen printing as shown in Figures 3(A) to 3(D), a height difference of approximately 8 μm occurred between the recessed portion 101 and the convex portion 102. In contrast, in the electrode layer 80 formed by screen printing as shown in Figures 4(A), 4(B), and 5, even when irregularities occurred on the surface of the coating layer 82 covering the linear portion 81, the height difference was suppressed to approximately 3 μm. It was confirmed that by using a method of forming the linear portion 81 and then forming the coating layer 82 to cover it, an electrode layer 80 with sufficient uniformity in film thickness can be realized.

[0061] The electrode layer 80 described above is used for one or both of the positive electrode layer 11 and the negative electrode layer 12 of the solid-state battery 1. For example, the electrode layer 80 including the linear portion 81 and the coating layer 82 is used as the positive electrode layer 11, and a cover layer 15 is formed on the outside thereon using a paste for the cover layer 15, thereby forming the layer part 41 of the solid-state battery 1 as shown in Figures 1(B), 1(C), and 2(B). Alternatively, the electrode layer 80 including the linear portion 81 and the coating layer 82 is used as the negative electrode layer 12, and a cover layer 15 is formed on the outside thereon using a paste for the cover layer 15, thereby forming the layer part 43 of the solid-state battery 1 as shown in Figures 1(B), 1(C), and 2(D). Then, as shown in Figures 1(B) and 1(C) above, layer parts 40, 42, 41, 44, 43, 42, 41, 44, 43, and 40 are stacked in the first direction D1 from bottom to top, and a solid battery 1 is manufactured.

[0062] For example, in the solid-state battery 1 shown in Figures 1(B) and 1(C) above, when the electrode layer 80 is used for the positive electrode layer 11, a linear portion 81 containing positive electrode active material is provided on the surface 13a side of the lower electrolyte layer 13, extending along the surface 13a, and a coating layer 82 containing positive electrode active material is provided so as to cover the surface 13a of the electrolyte layer 13 on which the linear portion 81 is provided, thereby forming the positive electrode layer 11. When the electrode layer 80 is used for the negative electrode layer 12, an upper electrolyte layer 13 is provided on the surface 11a side of the positive electrode layer 11, a linear portion 81 containing negative electrode active material is provided on the surface 13a side of the upper electrolyte layer 13, extending along the surface 13a, and a coating layer 82 containing negative electrode active material is provided so as to cover the surface 13a of the electrolyte layer 13 on which the linear portion 81 is provided, thereby forming the negative electrode layer 12. An upper electrolyte layer 13 is provided on the surface 12a side of the negative electrode layer 12, and a linear portion 81 containing positive electrode active material is provided on the surface 13a side of the upper electrolyte layer 13, extending along the surface 13a, and a coating layer 82 containing positive electrode active material is provided so as to cover the surface 13a of the electrolyte layer 13 on which the linear portion 81 is provided, thereby forming the positive electrode layer 11. For example, a solid-state battery 1 is manufactured to include such a repeating structure of electrolyte layer 13, positive electrode layer 11, electrolyte layer 13 and negative electrode layer 12.

[0063] For convenience, a solid-state battery 1 containing two positive electrode layers 11 and two negative electrode layers 12 is used as an example here. However, the number of layers of each of the positive electrode layers 11 and negative electrode layers 12 is not limited to this example, as long as the positive electrode layers 11 and negative electrode layers 12 are stacked in a first direction D1 via an electrolyte layer 13. An electrode layer 80 containing the linear portion 81 and coating layer 82 as described above can be used as one or more positive electrode layers 11 included in the solid-state battery 1. An electrode layer 80 containing the linear portion 81 and coating layer 82 as described above can be used as one or more negative electrode layers 12 included in the solid-state battery 1.

[0064] Furthermore, if the solid battery 1 contains multiple electrolyte layers 13, one electrolyte layer 13 is also referred to as the "first electrolyte layer," and its surface 13a is also referred to as the "first surface." The linear portion 81 and the coating layer 82 provided on the surface 13a side of the one electrolyte layer 13 are also referred to as the "first linear portion" and the "first coating layer," respectively, and the electrode layer 80 (positive electrode layer 11 or negative electrode layer 12) containing them is also referred to as the "first electrode layer." The active material (positive electrode active material or negative electrode active material) contained in the linear portion 81 and the coating layer 82 of the electrode layer 80 is also referred to as the "first polarity" "first active material."

[0065] The electrode layer 80 provided on the side of surface 13a of one electrolyte layer 13, on the side opposite to the first electrolyte layer 13 (surface 11a or surface 12a), is also called the "second surface," the other electrolyte layer 13 provided on that side is also called the "second electrolyte layer," and its surface 13a is also called the "third surface." The linear portion 81 and coating layer 82 provided on the side of surface 13a of the other electrolyte layer 13 are also called the "second linear portion" and the "second coating layer," respectively, and the electrode layer 80 (negative electrode layer 12 or positive electrode layer 11) including them is also called the "second electrode layer." The active material (negative electrode active material or positive electrode active material) contained in the linear portion 81 and coating layer 82 of the electrode layer 80 is also called the "second polarity" "second active material."

[0066] In the solid-state battery 1 shown in Figures 1(B) and 1(C) above, the positive electrode layer 11 or negative electrode layer 12 uses an electrode layer 80 as described above, that is, an electrode layer 80 including a linear portion 81 and a coating layer 82, having sufficient uniformity in terms of film thickness.

[0067] By using an electrode layer 80 with sufficient uniformity in film thickness as the positive electrode layer 11 or the negative electrode layer 12, in-plane distribution of the amount of positive electrode active material or negative electrode active material is suppressed. As a result, variations in the in-plane utilization rate of the positive electrode layer 11 or the negative electrode layer 12 using the electrode layer 80 are suppressed, and a decrease in the battery performance and lifespan of the solid-state battery 1 is suppressed.

[0068] Furthermore, when an electrode layer 80 having sufficient uniformity in film thickness is used as the negative electrode layer 12, the in-plane distribution of expansion of the negative electrode layer 12 during charging of the solid-state battery 1 is suppressed, thereby suppressing cracks and ruptures of the solid-state battery 1.

[0069] Furthermore, by using an electrode layer 80 with sufficient uniformity in film thickness as the positive electrode layer 11 or the negative electrode layer 12, the occurrence of irregularities on the outer surface (upper and lower surfaces) of the battery body 10 is suppressed, thereby suppressing a decrease in the shape stability of the solid battery 1.

[0070] As an example, in a solid-state battery 1 using electrode layers 100 formed by screen printing as shown in Figures 3(A) to 3(D) above as the positive electrode layer 11 and the negative electrode layer 12, the central part of the upper and lower surfaces of the battery body 10 was concave compared to the outer periphery. In contrast, in a solid-state battery 1 using electrode layers 80 formed by screen printing as shown in Figures 4(A), 4(B), and 5 above as the positive electrode layer 11 and the negative electrode layer 12, the height difference between the central part and the outer periphery of the upper and lower surfaces of the battery body 10 was reduced, and the upper and lower surfaces of the battery body 10 became closer to a flat shape.

[0071] Therefore, by using an electrode layer 80 with sufficient uniformity in film thickness as the positive electrode layer 11 or the negative electrode layer 12, a high-quality solid-state battery 1 is realized in which a decrease in battery performance, a decrease in lifespan, the occurrence of cracks and ruptures, and a decrease in shape stability are suppressed.

[0072] Further details will be provided regarding the electrode layer 80 used as the positive electrode layer 11 or the negative electrode layer 12 of the solid-state battery 1. Figure 6 illustrates an example of the configuration of an electrode layer according to the first embodiment. Figure 6(A) schematically shows a cross-sectional view of the main part of the electrode layer where the saddle phenomenon occurs. Figure 6(B) schematically shows a cross-sectional view of the main part of the electrode layer including the linear portion and the coating layer.

[0073] In the electrode layer 100 where the saddle phenomenon occurs, as shown in Figure 6(A), a recess 101 and a protrusion 102 on its outer side are formed. For example, the saddle phenomenon occurs such that the protrusion 102 is formed in a range of about 0.1 mm to 1 mm from the edge 103 of such an electrode layer 100. Now, let's consider the protrusion 102 of the electrode layer 100 where the saddle phenomenon has occurred as a semicircle 104 with radius R (shown as a dotted line in Figure 6(A)).

[0074] In this case, in the electrode layer 80 including the linear portion 81 and the coating layer 82 as shown in Figure 6(B), in order to make the film thickness uniform, it is desirable to set the width W1 of the linear portion 81 in the third direction D3 to a range of R or more and 3 × R or less (R ≤ W1 ≤ 3 × R). If R > W1, the linear portion 81 is small and the saddle phenomenon when forming the coating layer 82 cannot be sufficiently suppressed, and there is a possibility that a recess will be formed on the surface of the coating layer 82. If W1 > 3 × R, the linear portion 81 is large and there is a possibility that a convex portion will be formed on the surface of the coating layer 82.

[0075] Furthermore, in the electrode layer 80 including the linear portion 81 and the coating layer 82 as shown in Figure 6(B), in order to make the film thickness uniform, it is desirable that the width W2 between the edge 82a of the coating layer 82 and the linear portion 81 closest to it in the third direction D3 be in the range of R or more and 2×R or less (R≦W2≦2×R). In the range R>W2, the distance between the edge 82a and the linear portion 81 closest to it is small, and the linear portion 81 acts as a base for the edge of the coating layer 82, potentially causing the edge of the coating layer 82 to become thicker and forming a convex portion. In the range W2>2×R, the distance between the edge 82a and the linear portion 81 closest to it is large, potentially causing the film thickness at the edge of the coating layer 82 to become thinner and forming a concave portion.

[0076] In the above description, the example given for the plurality of linear portions 81 of the electrode layer 80 arranged in the third direction D3 is a plurality of linear portions 81 that are spaced apart from each other at a certain interval. In addition, the electrode layer 80 may include a plurality of linear portions 81 arranged in the third direction D3 that are spaced apart at different intervals, or a plurality of linear portions 81 that are adjacent to each other so as to be in contact with each other.

[0077] Furthermore, in the above description, the plurality of linear portions 81 arranged in the third direction D3 of the electrode layer 80 were exemplified as a plurality of parallel linear portions 81 extending linearly in the second direction D2. In addition, the electrode layer 80 may include a plurality of non-parallel linear portions 81 as a plurality of linear portions 81 arranged in the third direction D3, or it may include one or more linear portions 81 having a partially or entirely curved shape.

[0078] [Second Embodiment] Figure 7 illustrates an example of an electrode layer formation method according to the second embodiment. Figure 7(A) schematically shows a plan view of the main part of an example of the base layer formation process. Figure 7(B) schematically shows a plan view of the main part of an example of the linear part formation process. Figure 7(C) schematically shows a plan view of the main part of an example of the coating layer formation process. Figure 8 also illustrates an example of an electrode layer according to the second embodiment. Figure 8 schematically shows a cross-sectional view of the main part of an example of an electrode layer. Figure 8 is a schematic cross-sectional view of section VIII-VIII in Figure 7(C).

[0079] In this example, first, as shown in Figure 7(A), a base layer 83 is formed on the surface 50a of the support 50 using a screen printing method. The support 50 on which the base layer 83 is formed can be a PET film as described above, or a predetermined layer part (the electrolyte layer 13 of layer part 42 when a positive electrode layer 11 is formed on top of it, or the electrolyte layer 13 of layer part 44 when a negative electrode layer 12 is formed on top of it).

[0080] For forming the base layer 83, a paste for electrode layer 80A, i.e., a paste for positive electrode layer 11 or negative electrode layer 12, is used to form an electrode layer 80A that includes the base layer 83 and is used as either a positive electrode layer 11 or a negative electrode layer 12.

[0081] Following the example of the screen printing method described above, a predetermined screen corresponding to the base layer 83 to be formed is placed on the surface 50a of the support 50, and paste for the electrode layer 80A is applied to the surface 50a of the support 50 through the screen using a squeegee. After that, the screen is removed. For example, the applied paste for the electrode layer 80A may be heat-treated in a predetermined atmosphere under predetermined temperature and time conditions, and dried. In this way, a base layer 83 as shown in Figure 7(A) is formed on the surface 50a of the support 50.

[0082] The formed base layer 83 contains the active material. When the paste for the positive electrode layer 11 is used as the paste for the electrode layer 80A during screen printing of the base layer 83, the formed base layer 83 contains the positive electrode active material. When the paste for the negative electrode layer 12 is used as the paste for the electrode layer 80A during screen printing of the base layer 83, the formed base layer 83 contains the negative electrode active material.

[0083] The underlayer 83 formed on the surface 50a of the support 50 by screen printing undergoes a saddle phenomenon, which creates an inner recess 83a and an outer convex portion 83b. In Figure 7(A), the boundary between the recess 83a and the convex portion 83b of the underlayer 83 is shown schematically for the sake of explanation and is not necessarily limited to the illustrated position. The same applies to Figures 7(B) and 7(C).

[0084] After the formation of the base layer 83 having the recess 83a and the protrusion 83b, as shown in Figure 7(B), at least one linear portion 81 extending along the upper surface of the recess 83a or the surface 50a of the support 50 is formed on the recess 83a of the base layer 83 using a screen printing method. Here, as an example, a configuration is shown in which four linear portions 81 extending parallel in a second direction D2 are formed side by side in a third direction D3.

[0085] To form the linear portion 81, an electrode layer 80A paste is used to form an electrode layer 80A that includes a base layer 83 and the linear portion 81, which is used as a positive electrode layer 11 or a negative electrode layer 12, i.e., a paste for a positive electrode layer 11 or a paste for a negative electrode layer 12. Here, if the paste for a positive electrode layer 11 is used to form the base layer 83, the paste for a positive electrode layer 11 is also used to form the linear portion 81. If the paste for a negative electrode layer 12 is used to form the base layer 83, the paste for a negative electrode layer 12 is also used to form the linear portion 81.

[0086] Following the example of the screen printing method described above, a predetermined screen corresponding to the linear portion 81 to be formed is placed on the recess 83a of the base layer 83, and paste for the electrode layer 80A is applied to the recess 83a of the base layer 83 through the screen using a squeegee. After that, the screen is removed. For example, the applied paste for the electrode layer 80A may be heat-treated in a predetermined atmosphere under predetermined temperature and time conditions, and dried. In this way, linear portions 81, such as those shown in Figure 7(B), or four parallel linear portions 81, are formed on the recess 83a of the base layer 83.

[0087] The formed linear portion 81 contains the same active material as the base layer 83. When the paste for the positive electrode layer 11 is used as the paste for the electrode layer 80A during screen printing of the base layer 83 and the subsequent screen printing of the linear portion 81, both the formed base layer 83 and the linear portion 81 contain the positive electrode active material. When the paste for the negative electrode layer 12 is used as the paste for the electrode layer 80A during screen printing of the base layer 83 and the subsequent screen printing of the linear portion 81, both the formed base layer 83 and the linear portion 81 contain the negative electrode active material.

[0088] After the linear portion 81 is formed, as shown in Figure 7(C), a covering layer 82 is formed to cover the base layer 83 and the linear portion 81 provided on its recess 83a. Here, as an example, a covering layer 82 is formed to cover the base layer 83 and the four parallel linear portions 81 provided on its recess 83a.

[0089] For the formation of the coating layer 82, an electrode layer 80A paste, specifically a paste for the positive electrode layer 11 or a paste for the negative electrode layer 12, is used to form an electrode layer 80A that includes a base layer 83, a linear portion 81, and a coating layer 82, as described later, and is used as either a positive electrode layer 11 or a negative electrode layer 12. Here, if the paste for the positive electrode layer 11 is used to form the base layer 83 and the linear portion 81, the paste for the positive electrode layer 11 is also used to form the coating layer 82. If the paste for the negative electrode layer 12 is used to form the base layer 83 and the linear portion 81, the paste for the negative electrode layer 12 is also used to form the coating layer 82.

[0090] Following the example of the screen printing method described above, a predetermined screen corresponding to the coating layer 82 to be formed is placed on the base layer 83 on which the linear portions 81 are formed, and paste for the electrode layer 80A is applied to the base layer 83 through the screen using a squeegee. After that, the screen is removed. For example, the applied paste for the electrode layer 80A may be heat-treated in a predetermined atmosphere under predetermined temperature and time conditions, and dried. In this way, a coating layer 82 as shown in Figure 7(C) is formed on the base layer 83 on which the linear portions 81 are formed, for example, a coating layer 82 that covers the base layer 83 and the four parallel linear portions 81 provided in its recess 83a.

[0091] Furthermore, the heat treatment drying of the paste for the electrode layer 80A may be performed each time after coating to form the base layer 83, the linear portion 81, and the coating layer 82, respectively, or it may be omitted after coating to form the base layer 83 and the linear portion 81, and performed all at once after coating to form the coating layer 82.

[0092] The formed coating layer 82 contains the same active material as the base layer 83 and the linear portion 81. When the paste for the positive electrode layer 11 is used as the paste for the electrode layer 80A during screen printing of the base layer 83 and the linear portion 81, and subsequently the coating layer 82, the positive electrode active material is included in all of the formed base layer 83, the linear portion 81, and the coating layer 82. When the paste for the negative electrode layer 12 is used as the paste for the electrode layer 80A during screen printing of the base layer 83 and the linear portion 81, and subsequently the coating layer 82, the negative electrode active material is included in all of the formed base layer 83, the linear portion 81, and the coating layer 82.

[0093] Figure 8 shows an example of a cross-sectional structure in which a base layer 83 is formed on the surface 50a of the support 50, a plurality of linear portions 81 are formed in the recesses 83a, and a covering layer 82 is formed to cover them. Figure 8 is a schematic representation of the VIII-VIII cross-section in Figure 7(C).

[0094] As shown in Figure 8, a base layer 83 having a recess 83a and an outer protrusion 83b is formed on the surface 50a of the support 50. A plurality of linear portions 81 are formed side by side on the recess 83a of the base layer 83. Each formed linear portion 81 may have a curved surface 81a that bulges in an arc shape toward the opposite side from the support 50, as shown in Figure 8. A coating layer 82 is further formed on the base layer 83 on which the plurality of linear portions 81 are formed, so as to cover the base layer 83 and the plurality of linear portions 81. The base layer 83, the plurality of linear portions 81 and the coating layer 82 covering them form an electrode layer 80A that functions as the positive electrode layer 11 or the negative electrode layer 12 of the solid-state battery 1.

[0095] In the electrode layer 80A, which includes a base layer 83, a linear portion 81, and a coating layer 82, even when a recess 83a is formed in the base layer 83 due to the saddle phenomenon, the linear portion 81 is formed in the recess 83a, and the coating layer 82 is formed to cover the base layer 83 and the linear portion 81. As a result, in the electrode layer 80A, the linear portion 81 suppresses the occurrence of the saddle phenomenon when forming the coating layer 82, and the unevenness formed in the base layer 83 due to the saddle phenomenon when forming the base layer 83 is suppressed from being reflected on the surface of the coating layer 82. Therefore, the formation of unevenness on the surface of the electrode layer 80A, or the formation of relatively large unevenness, is suppressed. As a result, an electrode layer 80A with sufficient uniformity in film thickness is realized.

[0096] The electrode layer 80A described above is used for one or both of the positive electrode layer 11 and the negative electrode layer 12 of the solid-state battery 1. For example, the electrode layer 80A, including the base layer 83, the linear portion 81 and the coating layer 82, is used as the positive electrode layer 11, and a cover layer 15 is formed on the outside thereon using a paste for the cover layer 15, thereby forming the layer part 41 of the solid-state battery 1 as shown in Figures 1(B), 1(C), and 2(B). Alternatively, the electrode layer 80A, including the base layer 83, the linear portion 81 and the coating layer 82, is used as the negative electrode layer 12, and a cover layer 15 is formed on the outside thereon using a paste for the cover layer 15, thereby forming the layer part 43 of the solid-state battery 1 as shown in Figures 1(B), 1(C), and 2(D). Then, as shown in Figures 1(B) and 1(C) above, layer parts 40, 42, 41, 44, 43, 42, 41, 44, 43, and 40 are stacked in the first direction D1 from bottom to top, and a solid battery 1 is manufactured.

[0097] For example, in the solid-state battery 1 shown in Figures 1(B) and 1(C) above, when the electrode layer 80A is used for the positive electrode layer 11, a base layer 83 containing positive electrode active material is provided on the surface 13a side of the lower electrolyte layer 13, a linear portion 81 containing positive electrode active material is provided in the recess 83a, and a coating layer 82 containing positive electrode active material is provided so as to cover the base layer 83 on which the linear portion 81 is provided, thereby forming the positive electrode layer 11. When the electrode layer 80 is used for the negative electrode layer 12, an upper electrolyte layer 13 is provided on the surface 11a side of the positive electrode layer 11, a base layer 83 containing negative electrode active material is provided on the surface 13a side of the upper electrolyte layer 13, a linear portion 81 containing negative electrode active material is provided in the recess 83a, and a coating layer 82 containing negative electrode active material is provided so as to cover the base layer 83 on which the linear portion 81 is provided, thereby forming the negative electrode layer 12. An upper electrolyte layer 13 is provided on the surface 12a side of the negative electrode layer 12, and a base layer 83 containing positive electrode active material is provided on the surface 13a side of the upper electrolyte layer 13, and a linear portion 81 containing positive electrode active material is provided in the recess 83a of the base layer 83, and a coating layer 82 containing positive electrode active material is provided so as to cover the base layer 83 on which the linear portion 81 is provided, thereby forming the positive electrode layer 11. For example, a solid-state battery 1 is manufactured to include such a repeating structure of electrolyte layer 13, positive electrode layer 11, electrolyte layer 13 and negative electrode layer 12.

[0098] The number of layers in the positive electrode layer 11 and the negative electrode layer 12 is not limited to this example. As one or more positive electrode layers 11 included in the solid-state battery 1, an electrode layer 80A including the base layer 83, linear portion 81 and coating layer 82 as described above can be used. As one or more negative electrode layers 12 included in the solid-state battery 1, an electrode layer 80A including the base layer 83, linear portion 81 and coating layer 82 as described above can be used.

[0099] Furthermore, if the solid-state battery 1 contains multiple electrolyte layers 13, one electrolyte layer 13 is also referred to as the "first electrolyte layer," and its surface 13a is also referred to as the "first surface." The base layer 83, linear portion 81, and coating layer 82 provided on the surface 13a side of the one electrolyte layer 13 are also referred to as the "first base layer," "first linear portion," and "first coating layer," respectively, and the electrode layer 80A (positive electrode layer 11 or negative electrode layer 12) containing them is also referred to as the "first electrode layer." The active material (positive electrode active material or negative electrode active material) contained in the base layer 83, linear portion 81, and coating layer 82 of the electrode layer 80A is also referred to as the "first active material" of the "first polarity."

[0100] The electrode layer 80A provided on the side of surface 13a of one electrolyte layer 13, on the side opposite to the first electrolyte layer 13 (surface 11a or surface 12a), is also called the "second surface," the other electrolyte layer 13 provided on that side is also called the "second electrolyte layer," and its surface 13a is also called the "third surface." The base layer 83, linear portion 81, and coating layer 82 provided on the side of surface 13a of the other electrolyte layer 13 are also called the "second base layer," "second linear portion," and "second coating layer," respectively, and the electrode layer 80A (negative electrode layer 12 or positive electrode layer 11) including them is also called the "second electrode layer." The active material (negative electrode active material or positive electrode active material) contained in the base layer 83, linear portion 81, and coating layer 82 of the electrode layer 80A is also called the "second polarity" "second active material."

[0101] In the solid-state battery 1 shown in Figures 1(B) and 1(C) above, by using an electrode layer 80A having sufficient uniformity in film thickness as the positive electrode layer 11 or negative electrode layer 12, in-plane distribution of the amount of positive electrode active material or negative electrode active material is suppressed. As a result, variations in the in-plane utilization rate of the positive electrode layer 11 or negative electrode layer 12 using the electrode layer 80A are suppressed, and a decrease in the battery performance and lifespan of the solid-state battery 1 is suppressed.

[0102] Furthermore, when an electrode layer 80A having sufficient uniformity in film thickness is used as the negative electrode layer 12, the in-plane distribution of expansion of the negative electrode layer 12 during charging of the solid-state battery 1 is suppressed, thereby suppressing cracks and ruptures of the solid-state battery 1.

[0103] Furthermore, by using an electrode layer 80A with sufficient uniformity in film thickness as the positive electrode layer 11 or the negative electrode layer 12, the occurrence of irregularities on the outer surface (upper and lower surfaces) of the battery body 10 is suppressed, thereby suppressing a decrease in the shape stability of the solid battery 1.

[0104] Therefore, by using an electrode layer 80A with sufficient uniformity in film thickness as the positive electrode layer 11 or the negative electrode layer 12, a high-quality solid-state battery 1 is realized in which a decrease in battery performance, a decrease in lifespan, the occurrence of cracks and ruptures, and a decrease in shape stability are suppressed.

[0105] Furthermore, the electrode layer 80A may include multiple linear portions 81 arranged in the third direction D3 that are spaced at a constant interval from each other, multiple linear portions 81 that are spaced at different intervals from each other, or multiple linear portions 81 that are adjacent to each other so that they touch. In addition, the electrode layer 80A may include multiple parallel linear portions 81, multiple non-parallel linear portions 81, or one or more linear portions 81 that have a partially or entirely curved shape.

[0106] [Third Embodiment] Here, a configuration example of a solid-state battery 1 in which the electrode layer 80 described above is used as the positive electrode layer 11 and the negative electrode layer 12 will be described as a third embodiment.

[0107] Figure 9 illustrates a first example of the arrangement of electrode layers in a solid-state battery according to the third embodiment. Figure 9(A) schematically shows a plan view of the main part of an example of a layer component including a positive electrode layer. Figure 9(B) schematically shows a plan view of the main part of an example of a layer component including a negative electrode layer.

[0108] The layer part 41 shown in Figure 9(A) includes a positive electrode layer 11 and a cover layer 15 provided on the outside of it. As the positive electrode layer 11 of such a layer part 41, for example, an electrode layer 80 is provided as shown in Figure 9(A), that is, an electrode layer 80 including three linear portions 81 extending in the second direction D2 and a covering layer 82 covering them.

[0109] The layer part 43 shown in Figure 9(B) includes a negative electrode layer 12 and a cover layer 15 provided on its outside. As the negative electrode layer 12 of such a layer part 43, for example, an electrode layer 80 is provided as shown in Figure 9(B), that is, an electrode layer 80 including three linear portions 81 extending in the second direction D2 and a covering layer 82 covering them.

[0110] The layer part 41 shown in Figure 9(A) and the layer part 43 shown in Figure 9(B) are stacked via a layer part 42 or layer part 44, which includes an electrolyte layer 13 and a cover layer 15 provided on the outside of it, according to the example above, to realize a solid-state battery 1 (Figure 1).

[0111] The layer part 41 shown in Figure 9(A) and the layer part 43 shown in Figure 9(B) are configured such that, when stacked with their respective centerlines C1 and C2 aligned, the linear portions 81 of the electrode layers 80 used as the positive electrode layer 11 and the negative electrode layer 12 overlap in a plan view. As a result, the positive electrode layer 11 and the negative electrode layer 12, which have sufficient uniformity in film thickness, are stacked via the electrolyte layer 13, and irregularities on the outer surface of the battery body 10 formed by the stacking are suppressed, resulting in a solid-state battery 1 with excellent shape stability.

[0112] Furthermore, the number of linear portions 81 included in the positive electrode layer 11 of layer part 41 and the number of linear portions 81 included in the negative electrode layer 12 of layer part 43 are not limited to the examples shown in Figures 9(A) and 9(B). In addition, both the positive electrode layer 11 and the negative electrode layer 12 can be provided with an odd number of linear portions 81, or they can be provided with an even number of linear portions 81.

[0113] Figures 9(A) and 9(B) show an example in which the electrode layer 80 described in the first embodiment is used as the positive electrode layer 11 and the negative electrode layer 12. In addition, when using the electrode layer 80A described in the second embodiment, a configuration can be adopted in which the linear portions 81 of the positive electrode layer 11 and the negative electrode layer 12 overlap each other in a plan view.

[0114] Figure 10 is a diagram illustrating a second example of the electrode layer arrangement of a solid-state battery according to the third embodiment. Figure 10(A) schematically shows a plan view of the main part of an example of a layer component including a positive electrode layer. Figure 10(B) schematically shows a plan view of the main part of an example of a layer component including a negative electrode layer.

[0115] The layer part 41 shown in Figure 10(A) includes a positive electrode layer 11 and a cover layer 15 provided on the outside of it. As the positive electrode layer 11 of such a layer part 41, for example, an electrode layer 80 is provided as shown in Figure 10(A), that is, an electrode layer 80 including three linear portions 81 extending in the second direction D2 and a covering layer 82 covering them.

[0116] The layer part 43 shown in Figure 10(B) includes a negative electrode layer 12 and a cover layer 15 provided on its outside. As the negative electrode layer 12 of such a layer part 43, for example, an electrode layer 80 is provided as shown in Figure 10(B), that is, an electrode layer 80 including four linear portions 81 extending in the second direction D2 and a covering layer 82 covering them.

[0117] The layer part 41 shown in Figure 10(A) and the layer part 43 shown in Figure 10(B) are stacked via a layer part 42 or layer part 44, which includes an electrolyte layer 13 and a cover layer 15 provided on the outside of it, according to the example above, to realize a solid-state battery 1 (Figure 1).

[0118] The layer part 41 shown in Figure 10(A) and the layer part 43 shown in Figure 10(B) are configured such that, when stacked with their respective centerlines C1 and C2 aligned, the linear portions 81 of the electrode layers 80 used as the positive electrode layer 11 and the negative electrode layer 12 are arranged alternately in a plan view. As a result, the positive electrode layer 11 and the negative electrode layer 12, which have sufficient uniformity in film thickness, are stacked via the electrolyte layer 13, and irregularities on the outer surface of the battery body 10 formed thereby are suppressed, resulting in a solid-state battery 1 with excellent shape stability.

[0119] Furthermore, with respect to the electrode layers 80 used as the positive electrode layer 11 and the negative electrode layer 12, even if there are irregularities on the surface of the coating layer 82 corresponding to each linear portion 81, the arrangement of each linear portion 81 in a plan view prevents the recesses and protrusions of the positive electrode layer 11 and the negative electrode layer 12 from overlapping. Therefore, when the positive electrode layer 11 and the negative electrode layer 12 are laminated via the electrolyte layer 13, the irregularities of the positive electrode layer 11 and the negative electrode layer 12 tend to cancel each other out, preventing irregularities from forming on the outer surface of the battery body 10, and resulting in a solid-state battery 1 with excellent shape stability.

[0120] Furthermore, the number of linear portions 81 included in the positive electrode layer 11 of layer part 41, and the number of linear portions 81 included in the negative electrode layer 12 of layer part 43, are not limited to the examples shown in Figures 10(A) and 10(B). Also, for example, an odd number of linear portions 81 can be provided in the positive electrode layer 11 and an even number of linear portions 81 in the negative electrode layer 12. Alternatively, an even number of linear portions 81 can be provided in the positive electrode layer 11 and an odd number of linear portions 81 in the negative electrode layer 12.

[0121] Figures 10(A) and 10(B) show an example in which the electrode layer 80 described in the first embodiment is used as the positive electrode layer 11 and the negative electrode layer 12. In addition, when using the electrode layer 80A described in the second embodiment, a configuration can be adopted in which the linear portions 81 of the positive electrode layer 11 and the negative electrode layer 12 are arranged alternately in a plan view. [Explanation of Symbols]

[0122] 1 solid state battery 10 Battery Unit 10a Positive electrode lead side 10b Negative electrode lead surface 11a, 12a, 13a, 50a sides 11 Positive electrode layer 12 Negative electrode layer 13 Electrolyte layer 14 Power generation elements 15. Cover layer 20, 30 External connection terminals 40, 41, 42, 43, 44 layer parts 50 Support 60 screens 70 squeegee 80, 80A, 100 electrode layers 81 Linear part 81a Curved surface 82 Covering layer 82a, 103 end 83 Base layer 83a, 101 recess 83b, 102 convex part 100a Printed materials 104 Semicircle C1, C2 center line D1 1st direction D2 2nd direction D3 Third direction R radius W1, W2 width

Claims

1. The first electrolyte layer, A first electrode layer provided on the first surface side of the first electrolyte layer, Includes, The first electrode layer is The first electrolyte layer is provided on the first surface side and comprises at least one first linear portion extending along the first surface, A first coating layer covering the first surface side of the first electrolyte layer on which the first linear portion is provided, Includes, A solid-state battery in which the first linear portion and the first coating layer contain a first active material of first polarity.

2. The solid battery according to claim 1, wherein the first linear portion has a curved surface that bulges in an arc shape toward the side opposite to the first electrolyte layer when viewed in cross-section in a direction perpendicular to the direction in which the first linear portion extends.

3. The first electrode layer further includes a first underlayer provided on the first surface side of the first electrolyte layer, having a recess and a protrusion provided on the outside of the recess. The first sublayer contains the first active material, The first linear portion is provided in the recess, The solid battery according to claim 1, wherein the first coating layer covers the first underlayer in which the first linear portion is provided in the recess.

4. The solid battery according to claim 1, comprising a plurality of the first linear portions, wherein the plurality of the first linear portions are arranged in a row.

5. A second electrolyte layer is provided on the second surface side of the first electrode layer opposite to the first electrolyte layer side, A second electrode layer provided on the third surface side of the second electrolyte layer opposite to the first electrode layer side, It further includes, The aforementioned second electrode layer is The second electrolyte layer has at least one second linear portion provided on the third surface side and extending along the third surface, A second coating layer covering the third surface side of the second electrolyte layer on which the second linear portion is provided, Includes, The second linear portion and the second coating layer contain a second active material of second polarity, The solid-state battery according to claim 1, wherein, in a plan view, the first linear portion and the second linear portion are arranged alternately.

6. The process of forming the first electrolyte layer, A step of forming a first electrode layer on the first surface side of the first electrolyte layer, Includes, The step of forming the aforementioned first electrode layer is: The process involves forming at least one first linear portion extending along the first surface on the first surface side of the first electrolyte layer, A step of forming a first coating layer that covers the first surface side of the first electrolyte layer on which the first linear portion is formed, Includes, A method for manufacturing a solid battery, wherein the first linear portion and the first coating layer contain a first active material of first polarity.

Images