Secondary battery

Abstract

To provide a secondary battery having an electrode structure with a high energy density and a high adhesion to an electrode layer and a collector.SOLUTION: A secondary battery 1 includes: an electrolyte layer 2; and a first electrode structure 3 and a second electrode structure 4. The first electrode structure 3 has a first collector 5 and a pair of first electrode layers 6. The first collector 5 has a through-hole formation region 7 and the through-hole formation region includes an active material filling region 12. The active material filling region 12 is a region where a through-hole is filled with an active material so that the pair of first electrode layers 6 continue to each other.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a secondary battery.

Background Art

[0002] A secondary battery having an electrolyte layer and a pair of electrode structures (a positive electrode and a negative electrode) provided so as to sandwich the electrolyte layer in the thickness direction is known. Each electrode structure is provided with an electrode layer containing an active material and a current collector. One problem in such a secondary battery is to improve the energy density.

[0003] Techniques for improving the energy density are disclosed, for example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2020-181705). Patent Document 1 discloses "a secondary battery electrode having a plurality of metal porous plates stacked in the thickness direction and an electrode mixture filled in voids constituting the metal porous plates, wherein adjacent metal porous plates are press-bonded to each other."

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the description of Patent Document 1, a high energy density can be obtained. However, the higher the energy density, the better. Therefore, a further improvement in energy density is required. Further, usually, as described above, each electrode structure is provided with an electrode layer and a current collector. It is preferable that the adhesion between the electrode layer and the current collector is high. An electrode structure having a high energy density is required in which the active material and the current collector are firmly adhered to each other.

[0006] Accordingly, an object of the present invention is to provide a secondary battery having an electrode structure with a high energy density and a high adhesion between the electrode layer and the current collector.

Means for Solving the Problems

[0007] In one aspect, a secondary battery according to the present invention includes an electrolyte layer, and a first electrode structure and a second electrode structure arranged so as to sandwich the electrolyte layer. The first electrode structure has a first current collector and a pair of first electrode layers provided so as to sandwich the first current collector. The first current collector has a through-hole forming region in which a group of through-holes is formed. In at least a part of the through-hole forming region, the through-holes are filled with an active material so that the pair of first electrode layers are continuous.

Effects of the Invention

[0008] According to the present invention, there is provided a secondary battery having an electrode structure with a high energy density and a high adhesion between the electrode layer and the current collector.

Brief Description of the Drawings

[0009]

Figure 1

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Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0011] (1) First Embodiment FIG. 1 is a schematic cross-sectional view showing a secondary battery 1 according to the first embodiment.

[0012] In this embodiment, a case where the secondary battery 1 is an all-solid-state battery will be described as an example. In this specification, the "all-solid-state battery" is a secondary battery in which the electrolyte layer, the positive electrode layer, and the negative electrode layer are all substantially solid. However, each layer only needs to be "substantially" solid, and a small amount of liquid substance may be used even if it is a small amount.

[0013] As shown in FIG. 1, the secondary battery 1 has an electrolyte layer 2, a first electrode structure 3, and a second electrode structure 4. These are laminated along the lamination direction. The electrolyte layer 2 is sandwiched between the first electrode structure 3 and the second electrode structure 4 in the lamination direction.

[0014] Note that FIG. 1 shows a laminated structure including a plurality (two) of units (unit 18-1 and 18-2). And each unit 18 has a laminated structure composed of an electrolyte layer 2, a first electrode structure 3, and a second electrode structure 4. The first electrode structure 3 is common to one unit 18-1 and the other unit 18-2. Thus, the secondary battery 1 may include a plurality of units 18. However, the unit 18 included in the secondary battery 1 may be single.

[0015] The electrolyte layer 2 is a solid layer. The electrolyte layer 2 may be composed of a material that functions as an electrolyte layer in the secondary battery 1. The electrolyte layer 2 includes, for example, a resin binder and a solid electrolyte dispersed in the resin binder. The solid electrolyte includes, for example, a sulfide solid electrolyte. The thickness of the electrolyte layer 2 is, for example, 5 to 100 μm.

[0016] The first electrode structure 3 and the second electrode structure 4 are each a layer including an electrode layer and a current collector. One of the first electrode structure 3 and the second electrode structure 4 is a positive electrode structure, and the other is a negative electrode structure.

[0017] In the secondary battery 1 according to the present embodiment, ions (typically lithium ions) are conducted between the first electrode structure 3 and the second electrode structure 4 through the electrolyte layer 2 during charge and discharge. Specifically, during charging, the ions are conducted from the positive electrode side to the negative electrode side. During discharging, the ions are conducted from the negative electrode side to the positive electrode side.

[0018] Here, in the present embodiment, the configuration of the first electrode structure 3 is devised. This point will be described in detail below.

[0019] The first electrode structure 3 has a first current collector 5 and a pair of first electrode layers (6-1 and 6-2). The pair of first electrode layers (6-1 and 6-2) are provided so as to sandwich the first current collector 5 in the stacking direction. In other words, each of the first electrode layers (6-1 and 6-2) is sandwiched between the first current collector 5 and the electrolyte layer 2.

[0020] The first electrode layers (6-1 and 6-2) are layers containing an active material.

[0021] The first current collector 5 is provided for current collection. The first current collector 5 is in a sheet shape. A through-hole forming region 7 is provided in the first current collector 5. The through-hole forming region 7 is a region where a group of through-holes is provided. The group of through-holes has at least one through-hole. Preferably, the group of through-holes has a plurality of through-holes.

[0022] The through-hole forming region 7 has an active material filling region 12. The active material filling region 12 is a region that coincides with a pair of first electrode layers (6-1 and 6-2) when viewed along the stacking direction. In the active material filling region 12, the through-holes are filled with an active material. That is, in the active material filling region 12, the aperture diameter of each through-hole is larger than the particle diameter of the active material. And the particles of the active material are filled in each through-hole. Thereby, the pair of first electrode layers (6-1 and 6-2) are connected (linked) by the active material filling region 12.

[0023] The above is the outline of this embodiment. According to the above-described configuration, the pair of first electrode layers (6-1 and 6-2) are connected via the through-holes provided in the first current collector 5. Therefore, the first current collector 5 and the first electrode layers (6-1 and 6-2) are firmly adhered. When the adhesion between the current collector and the electrode layer is small, the first electrode structure 3 may deteriorate due to expansion and contraction during charge and discharge. On the other hand, according to this embodiment, since the first current collector 5 and the first electrode layers (6-1 and 6-2) are firmly adhered, deterioration of the first electrode structure 3 accompanying charge and discharge is suppressed.

[0024] Also, according to this embodiment, the first current collector 5 is sandwiched between a pair of first electrode layers (6-1 and 6-2). That is, the first current collector 5 does not exist over the entire first electrode structure 3 in the thickness direction, but exists only in a part in the thickness direction. In other words, the thickness of the first current collector 5 is thinner than the thickness of the entire first electrode structure 3. Such a configuration is advantageous from the viewpoint of energy density. In the first electrode structure 3, the higher the amount of the active material, the higher the energy density. If the first current collector 5 exists over the entire first electrode structure 3 in the thickness direction, the amount of the active material existing in the first electrode structure 3 will decrease due to the presence of the first current collector 5. When the amount of the active material is small, the energy density decreases. On the other hand, according to this embodiment, since the first current collector 5 is thin, the amount of the active material included in the first electrode structure 3 can be ensured. Thereby, a high energy density can be realized.

[0025] In the example shown in FIG. 1, the first current collector 5 has a surplus region 19. The surplus region 19 is a region located outside a pair of first electrode layers (6-1 and 6-2) when viewed along the stacking direction. That is, the surplus region 19 is a region protruding from the pair of first electrode layers (6-1 and 6-2). A pore region 13 and a dense region 11 are provided in the surplus region 19. The pore region 13 is a part of the through-hole forming region 7 and is a region where the through-hole is not filled. That is, the pore region 13 is a region where the through-hole is formed but the through-hole is a pore. On the other hand, the dense region 11 is a region where no through-hole is provided. In the example shown in FIG. 1, the dense region 11 is provided outside the pore region 13 when viewed along the stacking direction.

[0026] According to the configuration as described above, since the pore region 13 and the dense region 11 are provided in the surplus region 19, the stress generated in the first current collector 5 can be released. For example, during the manufacture of the secondary battery 1, the laminate including the first electrode structure 3 may be pressed. Stress may be generated in the first current collector 5 during pressing. Also, during charge and discharge, the first electrode structure 3 may expand and contract. Stress may also be generated in the first current collector 5 during expansion and contraction. Due to the stress, the first current collector 5 may be damaged. In contrast, according to the present embodiment, since the pore region 13 and the dense region 11 are provided in the surplus region 19, the stress can be released. Thereby, the damage of the first current collector 5 due to the stress is prevented. Also, the first current collector 5 can easily follow the expansion and contraction due to charge and discharge.

[0027] Note that the shape of each through-hole 10 is not particularly limited. In the example shown in FIG. 1, each through-hole extends linearly along the stacking direction, but it does not necessarily have to extend linearly. On the other hand, FIG. 2 is a plan view showing an example of a preferable shape of each through-hole 10. As shown in FIG. 2, when viewed along the stacking direction, each through-hole 10 is preferably circular. If the through-hole 10 is circular, stress does not concentrate on the edge portion of the through-hole. As a result, breakage of the first current collector 5 due to stress concentration can be prevented. Consequently, it is possible to prevent the first electrode structure 3 from collapsing.

[0028] Subsequently, referring to FIG. 3, the positional relationship between the pair of first electrode layers (6-1 and 6-2) and the first current collector 5 will be described. FIG. 3 is a plan view showing an example of the first electrode structure 3. In the example shown in FIG. 3, when viewed along the stacking direction, the outer shape of the pair of first electrode layers (6-1 and 6-2) has corners. These corners are located on the through-holes included in the through-hole group. According to such a configuration, the pair of first electrode layers (6-1 and 6-2) are continuous with each other via the through-holes at the edges (corners). As a result, the adhesion between the pair of first electrode layers (6-1 and 6-2) and the first current collector 5 is further enhanced.

[0029] In a more preferable aspect, as shown in FIG. 3, the "sides" of the outer shape of the pair of first electrode layers (6-1 and 6-2) cross the through-holes when viewed along the stacking direction. According to such a configuration, since the pair of first electrode layers (6-1 and 6-2) are continuous via the through-holes at the outer peripheral ends, the adhesion between the pair of first electrode layers (6-1 and 6-2) and the first current collector 5 is further enhanced.

[0030] As described above, the first electrode structure 3 may be on the positive electrode side or the negative electrode side. In a preferred embodiment, the first electrode structure 3 is a structure on the positive electrode side. That is, it is preferable that the pair of first electrode layers (6-1 and 6-2) are positive electrode layers containing a positive electrode active material. The positive electrode layer is formed of, for example, a material containing a resin binder and a positive electrode active material dispersed in the resin binder. As the positive electrode active material, for example, a lithium metal composite oxide or the like is used. The thickness of each positive electrode layer (the first electrode layer 6-1 and the first electrode layer 6-2) is, for example, 10 to 1000 μm, preferably 30 to 500 μm.

[0031] Subsequently, returning to FIG. 1, the second electrode structure 4 will be described. The configuration of the second electrode structure 4 is not particularly limited. In the example shown in FIG. 1, the second electrode structure 4 has a second current collector 8 and a pair of second electrode layers (9-1 and 9-2).

[0032] Each second electrode layer (9-1 and 9-2) can be, for example, a layer containing an active material.

[0033] On the other hand, when the second electrode structure 4 is a structure on the negative electrode side, each second electrode layer (9-1 and 9-2) may be a negative electrode intermediate layer. The negative electrode intermediate layer is a layer provided to protect the electrolyte layer 2 in a lithium deposition type all-solid-state battery. A lithium deposition type all-solid-state battery is an all-solid-state battery configured such that metallic lithium is deposited between the electrolyte layer 2 and the negative electrode current collector during charging. In such a battery, the metallic lithium deposited during charging functions as a negative electrode active material. Here, if metallic lithium is deposited in contact with the electrolyte layer 2, the electrolyte layer 2 may be damaged. Therefore, a negative electrode intermediate layer is provided between the electrolyte layer 2 and the negative electrode current collector. The negative electrode intermediate layer is realized by, for example, a layer containing silver particles and carbon particles. During charging, metallic lithium is deposited as a negative electrode active material between the negative electrode intermediate layer and the negative electrode current collector. On the other hand, during discharging, the metallic lithium present in the negative electrode conducts to the positive electrode side. Therefore, in the discharged state, there may be almost no metallic lithium as a negative electrode active material.

[0034] (2) Second Embodiment Next, a second embodiment will be described. Regarding the points where the same configuration as that of the first embodiment can be adopted, detailed description will be omitted. FIG. 4 is a schematic cross-sectional view showing a secondary battery 1 according to the second embodiment.

[0035] In this embodiment, the configuration of the electrolyte layer 2 is changed from that of the first embodiment. Specifically, the side surfaces of the pair of first electrode layers (6-1 and 6-2) are covered by the electrolyte layer 2. Along with this, a part of the first current collector 5 is also filled with the electrolyte.

[0036] Specifically, as shown in FIG. 4, the electrolyte layer 2 has a central portion (2-1 and 2-4), a first side surface portion (2-2), and a second side surface portion (2-3). The central portion (2-1 and 2-4) is a portion sandwiched between the first electrode structure 3 and the second electrode structure 4 in the stacking direction. In other words, the central portion (2-1 and 2-4) is a portion that covers the upper surfaces of the respective first electrode layers (6-1 and 6-2). The first side surface portion 2-2 is a portion that covers the side surface of one first electrode layer 6-1. The second side surface portion 2-3 is a portion that covers the other first electrode layer 6-2.

[0037] The first side surface portion 2-2 and the second side surface portion 2-3 are continuous through a through hole provided in the first current collector 5. Specifically, in the first current collector 5, an electrolyte filling region 14 is provided in a through hole forming region 7. The electrolyte filling region 14 is a region provided outside the active material filling region 12 and is a region that overlaps with the first side surface portion 2-2 and the second side surface portion 2-3. In the electrolyte filling region 14, the through hole is filled with the electrolyte. As a result, the first side surface portion 2-2 and the second side surface portion 2-3 are continuous. Note that the pore region 13 is provided outside the electrolyte filling region 14.

[0038] According to this embodiment, since the side surfaces of the pair of first electrode layers 6-1 are covered by the electrolyte layer 2, a short circuit between the first electrode structure 3 and the second electrode structure 4 is prevented. In addition, since the first side surface portion 2-2 and the second side surface portion 2-3 are continuous through the through hole, the adhesion between the first current collector 5 and the electrolyte layer 2 is enhanced. Thereby, the strength of the first electrode structure 3 is further improved.

[0039] (3) Third Embodiment Subsequently, the third embodiment will be described. Regarding points where the same configuration as the above-described embodiment can be adopted, detailed description will be omitted. FIG. 5 is a schematic cross-sectional view showing the secondary battery 1 according to the third embodiment.

[0040] In this embodiment, an electron conduction layer 15 is provided between the surface of the first current collector 5 and the pair of first electrode layers (6-1 and 6-2).

[0041] The electron conduction layer 15 is a layer through which electrons can conduct. The electron conduction layer 15 is formed of a material different from that of the pair of first electrode layers (6-1 and 6-2) and the first current collector 5. By using the electron conduction layer 15, the interfacial resistance between the first current collector 5 and the pair of first electrode layers (6-1 and 6-2) can be reduced, and the characteristics as a battery can be improved. The electron conduction layer 15 is preferably composed of a material that enhances the adhesion between the pair of first electrode layers (6-1 and 6-2) and the first current collector 5. The electron conduction layer 15 is preferably thinner than each of the first electrode layers (6-1 and 6-2). The electron conduction layer 15 can be realized, for example, by a carbon layer. The thickness of the electron conduction layer 15 is, for example, 0.3 to 5.0 μm, preferably 0.5 to 3.0 μm.

[0042] (Modification) Next, a modification of this embodiment will be described. FIG. 6 is a schematic cross-sectional view showing a secondary battery 1 according to a modification of the third embodiment. As shown in FIG. 6, in this modification, the electron conductive layer 15 is formed not only on the surface of the first current collector 5 but also on the inner surface of the through-hole. That is, the electron conductive layer 15 covers the side wall of the through-hole. According to such a configuration, the interfacial resistance between the first current collector 5 and the pair of first electrode layers (6-1 and 6-2) can be further reduced, and the characteristics of the battery can be further improved.

[0043] (4) Fourth Embodiment Next, the fourth embodiment will be described. Regarding the points where the same configuration as the above-described embodiments can be adopted, detailed description will be omitted. FIG. 7 is a schematic cross-sectional view showing a secondary battery 1 according to the fourth embodiment.

[0044] As shown in FIG. 7, in this embodiment, in the first current collector 5, a resin filling region 16 is provided in the surplus region 19. The resin filling region 16 is a part of the through-hole forming region 7 and is a region filled with a stress-relieving resin in the through-hole. Note that the void region 13 (see FIG. 1) in the first embodiment is not provided. In other words, in this embodiment, instead of the void region 13 in the first embodiment, a resin filling region 16 is provided.

[0045] The stress-relieving resin may be any resin that can relieve the stress of the first current collector 5. For example, an elastomeric resin can be used as the stress-relieving resin. For example, an acrylic resin, a silicone resin, or the like can be used as the stress-relieving resin.

[0046] According to this embodiment, the presence of the resin filling region 16 can relieve the deformation of the first current collector 5 due to stress. As described above, stress may be generated in the first current collector 5 due to pressing or the like during manufacturing. Alternatively, for example, stress may be generated in the first current collector 5 due to expansion and contraction accompanying charge and discharge. As a result, stress may occur in the first current collector 5 and cause deformation. On the other hand, according to this embodiment, since the stress is relieved by the resin filling region 16, the deformation of the first current collector 5 is suppressed. Also, with respect to expansion and contraction due to charge and discharge, the first current collector 5 can more easily follow.

[0047] (5) Fifth Embodiment Next, the fifth embodiment will be described. Regarding points where the same configurations as those of the above-described embodiments can be adopted, detailed descriptions will be omitted. FIG. 8 is a schematic cross-sectional view showing the secondary battery 1 according to the fifth embodiment.

[0048] In this embodiment, the configuration of the second electrode structure 4 is devised. Specifically, the second current collector 8 has a porous structure.

[0049] According to this embodiment, since the second current collector 8 has a porous structure, the flexibility of the second current collector 8 is improved. The secondary battery 1 may expand and contract accompanying charge and discharge. Since the second current collector 8 has high flexibility, the second current collector 8 can more easily follow the expansion and contraction. Thereby, breakage of the secondary battery 1 due to expansion and contraction is prevented.

[0050] (6) Sixth Embodiment Next, the sixth embodiment will be described. Regarding points where the same configurations as those of the above-described embodiments can be adopted, detailed descriptions will be omitted. FIG. 9 is a schematic cross-sectional view showing the secondary battery 1 according to the sixth embodiment.

[0051] This embodiment can also be said to be a modification of the fifth embodiment. In this embodiment, the configuration of the second electrode structure 4 is further improved. The second current collector 8 has a porous structure, similar to the fifth embodiment. Also, the second current collector 8 is sandwiched between a pair of second electrode layers (9-1 and 9-2). The pair of second electrode layers (9-1 and 9-2) are each an anode intermediate layer (17-1 and 17-2). That is, in the secondary battery 1 according to this embodiment, lithium is deposited between the pair of anode intermediate layers (17-1 and 17-2) and the electrolyte layer 2 during charging. Here, the inner surface of the pores in the second current collector 8 is coated with the same material as the constituent material of the anode intermediate layer (17-1 and 17-2).

[0052] According to the configuration of this embodiment, during charging, the location where metallic lithium is deposited can be controlled within the pores in the porous structure. Thereby, deposition of metallic lithium on unnecessary portions can be prevented. As a result, short circuit due to lithium dendrites can be prevented.

[0053] (7) Seventh Embodiment Next, the seventh embodiment will be described. Regarding points where the same configuration as the previously described embodiments can be adopted, detailed description will be omitted. FIG. 10 is a schematic cross-sectional view showing the secondary battery 1 according to the seventh embodiment.

[0054] This embodiment can also be said to be a modification of the sixth embodiment. In this embodiment, the anode intermediate layer 17 exists only on the inner surface of the pores of the second current collector 8. There is no anode intermediate layer on both surfaces of the second current collector 8.

[0055] According to the configuration of this embodiment, similar to the sixth embodiment, the location where metallic lithium is deposited during charging can be controlled. In addition, since there is no anode intermediate layer on both surfaces of the second current collector 8, the thickness of the secondary battery 1 can be reduced. Thereby, the energy density can be further improved.

[0056] As described above, the present invention has been explained using the first to seventh embodiments. It should be noted that these embodiments and modifications are not independent of each other, and it is also possible to use them in combination within a non - conflicting range.

[0057] Hereinafter, representative embodiments of the present invention and their effects are summarized as an appendix.

[0058] (Appendix 1) A secondary battery comprising an electrolyte layer 2, and a first electrode structure 3 and a second electrode structure 4 arranged so as to sandwich the electrolyte layer. The first electrode structure 3 has a first current collector 5 and a pair of first electrode layers (6 - 1 to 6 - 2) provided so as to sandwich the first current collector 5 and containing an active material. The first current collector 5 has a through - hole forming region 7 in which a group of through - holes each having at least one through - hole is formed. The through - hole forming region 7 includes an active material filling region 12. The active material filling region 12 is a region that coincides with the pair of first electrode layers (6 - 1 to 6 - 2) when viewed along the stacking direction, and is a region in which the through - holes are filled with the active material so that the pair of first electrode layers are continuous with each other.

[0059] According to the above configuration, since the pair of first electrode layers (6 - 1 to 6 - 2) are connected via the through - holes, the pair of first electrode layers (6 - 1 to 6 - 2) and the first current collector 5 are firmly adhered. Also, since the thickness of the first current collector 5 is smaller than the thickness of the first electrode structure 3, the amount of active material can be ensured and the energy density is improved.

[0060] (Appendix 2) The secondary battery according to Appendix 1, wherein the first current collector 5 has a surplus region 19 which is a region outside the pair of first electrode layers when viewed along the stacking direction. The surplus region 19 is a part of the through - hole forming region 7 and has a void region 13 which is a region where the through - holes are not filled and a dense region 11 which is a region where no through - holes are provided.

[0061] According to the above configuration, since the surplus region of the first current collector is provided with a void region and a dense region, the stress generated in the first current collector 5 is relaxed.

[0062] (Appendix 3) The secondary battery according to Appendix 1 or 2, wherein the electrolyte layer 2 has a central portion 2-1 sandwiched between the first electrode structure 3 and the second electrode structure 4 in the stacking direction, a first side portion 2-2 covering one side surface of the pair of first electrode layers, and a second side portion 2-3 covering the other side surface of the pair of first electrode layers. The through-hole forming region 7 further has an electrolyte filling region 14 provided outside the active material filling region 12 and overlapping with the first side portion 2-2 and the second side portion 2-3. In the electrolyte filling region 14, the through-hole is filled with an electrolyte so that the first side portion 2-2 and the second side portion 2-3 are continuous. Secondary battery.

[0063] According to the above configuration, the adhesion between the electrolyte layer 2 and the first current collector 5 is improved, so that the strength of the first electrode structure 3 can be increased.

[0064] (Appendix 4) The secondary battery according to Appendix 1 or 2, wherein the first current collector 5 has a surplus region 19 which is a region outside the pair of first electrode layers when viewed along the stacking direction. The surplus region 19 is a part of the through-hole forming region 7 and has a resin filling region 16 which is a region where the through-hole is filled with a stress relaxation resin. Secondary battery.

[0065] According to the above configuration, the stress generated in the first current collector 5 is relaxed by the resin filling region 16.

[0066] (Appendix 5) The secondary battery according to any one of Appendices 1 to 4, wherein the through-hole is circular when viewed along the stacking direction. Secondary battery.

[0067] According to the above configuration, it is possible to prevent stress from concentrating on the first current collector 5 at the edge portion of the through-hole, and more reliably suppress the deterioration of the first current collector 5.

[0068] (Appendix 6) The secondary battery according to any one of Supplementary Notes 1 to 5, wherein when viewed along the stacking direction, the outer shapes of the pair of first electrode layers have corners, and the corners are located on the through holes.

[0069] According to the above configuration, the pair of first electrode layers are continuous through the through holes at the corners. As a result, the adhesion between the pair of first electrode layers and the first current collector 5 is further enhanced.

[0070] (Supplementary Note 7) The secondary battery according to any one of Supplementary Notes 1 to 6, wherein the first electrode structure 3 further has an electron conductive layer 15 provided between the surface of the first current collector and the pair of first electrode layers.

[0071] According to the above configuration, the interfacial resistance between the first current collector and the pair of first electrode layers is reduced, and the characteristics of the battery are improved.

[0072] (Supplementary Note 8) The secondary battery according to Supplementary Note 7, wherein the electron conductive layer 15 further covers the side walls of the through holes.

[0073] According to the above configuration, the interfacial resistance between the first current collector and the pair of first electrode layers is further reduced, and the characteristics of the battery are further improved.

[0074] (Supplementary Note 9) The secondary battery according to any one of Supplementary Notes 1 to 8, wherein the first electrode structure 3 is a positive electrode, the second electrode structure 4 is a negative electrode, the second electrode structure 4 has a second current collector 8 that is a negative electrode current collector, and the second current collector 8 has a porous structure.

[0075] According to the above configuration, the flexibility of the second current collector 8 can be enhanced.

[0076] (Supplementary Note 10) The secondary battery according to Supplementary Note 9, wherein the second electrode structure 4 further has a pair of negative electrode intermediate layers (17-1, 17-2) provided so as to sandwich the second current collector 8, and the secondary battery 1 is configured such that lithium is deposited between the pair of negative electrode intermediate layers (17-1, 17-2) and the second current collector 8 during charging, and the inner surface of the pores of the second current collector 8 is coated with the same material as the constituent materials (17-1, 17-2) of the pair of negative electrode intermediate layers.

[0077] According to the above configuration, the location where lithium is deposited can be controlled, and short circuit due to lithium dendrites can be prevented.

[0078] (Supplementary Note 11) The secondary battery according to Supplementary Note 9, wherein the inner surface of the pores of the second current collector 8 is covered by the negative electrode intermediate layer 17, and the secondary battery 1 is configured such that lithium is deposited between the negative electrode intermediate layer 17 and the second current collector 8 during charging, and the negative electrode intermediate layer 17 is not provided on both surfaces of the second current collector 8 in the stacking direction.

[0079] According to the above configuration, the location where lithium is deposited can be controlled, and short circuit due to lithium dendrites can be prevented.

Explanation of Reference Numerals

[0080] 1... secondary battery, 2... electrolyte layer, 2-1... central part, 2-2... first side face part, 2-3... second side face part, 2-4... central part, 3... first electrode structure, 4... second electrode structure, 5... first current collector, 6-1~6-2... first electrode layer, 7... through-hole forming region, 8... second current collector, 9-1~9-2... second electrode layer, 10... through-hole, 11... dense region, 12... active material filling region, 13... pore region, 14... electrolyte filling region, 15... electron conduction layer, 16... resin filling region, 17-1~17-2... negative electrode intermediate layer, 18-1~18-2... unit, 19... surplus region

Claims

1. An electrolyte layer, A first electrode structure and a second electrode structure arranged so as to sandwich the electrolyte layer, comprising The first electrode structure is A first current collector, A pair of first electrode layers provided so as to sandwich the first current collector and containing an active material, having The first current collector has a through-hole forming region in which a group of through-holes each having at least one through-hole is formed, The through-hole forming region includes an active material filling region, The active material filling region is a region that coincides with the pair of first electrode layers when viewed along the stacking direction, and is a region in which the through-holes are filled with the active material so that the pair of first electrode layers are continuous with each other. A secondary battery.

2. The secondary battery according to claim 1, The first current collector has a surplus region that is a region outside the pair of first electrode layers when viewed along the stacking direction, The surplus region is a part of the through-hole forming region and has a pore region that is a region where the through-holes are not filled and a dense region that is a region where the through-holes are not provided. A secondary battery.

3. The secondary battery according to claim 1 or 2, The electrolyte layer has a central portion that is a portion sandwiched between the first electrode structure and the second electrode structure in the stacking direction, a first side portion that covers one side surface of the pair of first electrode layers, and a second side portion that covers the other side surface of the pair of first electrode layers, and the through-hole forming region further has an electrolyte filling region that is a region provided outside the active material filling region and overlaps with the first side portion and the second side portion. ​ In the electrolyte filling region, the through hole is filled with an electrolyte such that the first side surface and the second side surface are continuous. Secondary battery.

4. The secondary battery according to claim 1, The first current collector has a surplus region which is a region outside the pair of first electrode layers when viewed along the stacking direction. The surplus region, is a part of the through hole forming region and has a resin filling region which is a region where the through hole is filled with a stress relaxation resin. Secondary battery.

5. The secondary battery according to claim 1 or 2, When viewed along the stacking direction, the through hole is circular. Secondary battery.

6. The secondary battery according to claim 1 or 2, When viewed along the stacking direction, the outer shape of the pair of first electrode layers has corners. The corners are located on the through hole. Secondary battery.

7. The secondary battery according to claim 1 or 2, The first electrode structure further has an electron conduction layer provided between the surface of the first current collector and the pair of first electrode layers. Secondary battery.

8. The secondary battery according to claim 7, The electron conduction layer further covers the side wall of the through hole. Secondary battery.

9. The secondary battery according to claim 1 or 2, The first electrode structure is a positive electrode, The second electrode structure is a negative electrode, The second electrode structure has a second current collector which is a negative electrode current collector. The second current collector has a porous structure. Secondary battery.

10. The secondary battery according to claim 9, wherein the second electrode structure further has a pair of negative electrode intermediate layers provided so as to sandwich the second current collector, and the secondary battery is configured such that lithium is deposited between the pair of negative electrode intermediate layers and the second current collector during charging, and an inner surface of pores of the second current collector is coated with the same material as a constituent material of the pair of negative electrode intermediate layers. Secondary battery.

11. The secondary battery according to claim 9, wherein an inner surface of pores of the second current collector is coated with a negative electrode intermediate layer, and the secondary battery is configured such that lithium is deposited between the negative electrode intermediate layer and the second current collector during charging, and the negative electrode intermediate layer is not provided on both surfaces of the second current collector in the stacking direction. Secondary battery.

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