Solid state battery

Abstract

The present disclosure provides a solid-state battery suitable for improving volume energy density and suitable for large-current discharge applications. A solid-state battery (100) according to the present disclosure comprises: a ceramic package (10) that includes a package body (20) and a lid body (30); a battery element (40) that includes a first electrode (41), a solid electrolyte layer (43), and a second electrode (42), and is accommodated in the ceramic package (10) such that the first electrode (41), the solid electrolyte layer (43), and the second electrode (42) are arranged in the stated order from the lid-body (30) side toward the inner bottom surface (20b) of the package body (20); and a current collection member (60) that includes a locking part (60k) locked to the package body (20), is disposed along a side surface (41p) of the first electrode (41) so as to surround the first electrode (41), and is electrically connected to the first electrode (41).

Description

solid state battery

[0001] The present disclosure relates to solid-state batteries.

[0002] The use of ceramic packages as containers for solid-state batteries has been considered. The advantages of using ceramic packages include high airtightness inside the ceramic package, the ability to surface-mount the solid-state battery on a circuit board together with electronic components, and the ability to impart high heat resistance to the solid-state battery.

[0003] Patent Document 1 describes an electrochemical element including a conductive plate disposed between a power generating element and a lid member, in which an elastic engaging portion of the conductive plate is inserted into an insertion hole of a recessed container.

[0004] Patent Document 2 discloses a stacked-type all-solid-state secondary battery. The stacked-type all-solid-state secondary battery includes a stacked body including a positive electrode, a negative electrode, and a solid electrolyte layer. External electrodes are provided on two end faces of the stacked body, respectively.

[0005] International Publication No. 2024 / 034601 International Publication No. 2020 / 184652

[0006] The electrochemical element described in Patent Document 1 requires a conductive plate disposed on the upper surface of the power generating element. In this case, a sufficiently large space is required between the power generating element and the lid, making it difficult to increase the volumetric energy density of the electrochemical element.

[0007] In the stacked-type all-solid-state secondary battery described in Patent Document 2, the contact area between the external electrodes and the current collector is small, making the stacked-type all-solid-state secondary battery described in Patent Document 2 unsuitable for applications requiring large current discharge.

[0008] The present disclosure provides a solid-state battery suitable for improving volumetric energy density and for use in large-current discharge applications.

[0009] The present disclosure provides a solid-state battery comprising: a ceramic package including a package body and a lid; a battery element including a first electrode, a solid electrolyte layer, and a second electrode, the battery element being housed in the ceramic package such that the first electrode, the solid electrolyte layer, and the second electrode are arranged in this order from the lid side toward the inner bottom surface of the package body; and a current collecting member including a locking portion locked to the package body, disposed along a side surface of the first electrode so as to surround the first electrode, and electrically connected to the first electrode.

[0010] According to the present disclosure, it is possible to provide a solid-state battery that is suitable for improving volumetric energy density and for use in large current discharge applications.

[0011] FIG. 1 is a cross-sectional view of a solid state battery according to embodiment 1. FIG. 2 is a plan view of the solid state battery according to embodiment 1 with the lid removed. FIG. 3 is a perspective view of a package body. FIG. 4A is a plan view of a current collecting member according to a modified example. FIG. 4B is a plan view of a current collecting member according to another modified example. FIG. 4C is a plan view of a current collecting member according to yet another modified example. FIG. 5A is a cross-sectional view of a battery element according to a modified example. FIG. 5B is a cross-sectional view showing a state in which a current collecting member is attached to the battery element shown in FIG. 5A. FIG. 6 is a cross-sectional view of a solid state battery according to embodiment 2. FIG. 7 is a plan view of the solid state battery according to embodiment 2 with the lid removed.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.

[0013] (Embodiment 1) Fig. 1 is a cross-sectional view taken along line II of a solid-state battery 100 according to Embodiment 1. The solid-state battery 100 includes a ceramic package 10, a battery element 40, and a current collecting member 60. The ceramic package 10 includes a cavity CA. The battery element 40 is disposed in the cavity CA. The current collecting member 60 is a member for electrically connecting the ceramic package 10 and the battery element 40. The solid-state battery 100 can be surface-mounted on a circuit board by soldering.

[0014] The ceramic package 10 includes a package body 20 and a lid 30. The package body 20 is a concave member having a cavity CA formed therein. The lid 30 is bonded to the package body 20 so as to seal the cavity CA.

[0015] The ceramic package 10 has a rectangular shape, typically a square shape, in a plan view. However, the shape of the ceramic package 10 is not particularly limited and may be, for example, a circular shape in a plan view. The cavity CA has a circular shape in a plan view. However, the shape of the cavity CA is not particularly limited and may be, for example, a rectangular shape, typically a square shape in a plan view.

[0016] The package body 20 is made of a ceramic material such as alumina ceramic or aluminum nitride ceramic. The lid 30 is made of a metal material with a low thermal expansion coefficient such as Kovar. The lid 30 may also be made of an insulating material such as ceramic.

[0017] The battery element 40 includes a first electrode 41, a solid electrolyte layer 43, and a second electrode 42. The first electrode 41, the solid electrolyte layer 43, and the second electrode 42 are stacked in this order. The stacking direction of the first electrode 41, the solid electrolyte layer 43, and the second electrode 42 coincides with the depth direction of the cavity CA. The battery element 40 is housed in the ceramic package 10 so that the first electrode 41, the solid electrolyte layer 43, and the second electrode 42 are arranged in this order from the lid 30 side toward the inner bottom surface 20b of the package body 20. The first electrode 41 has a polarity opposite to that of the second electrode 42. The first electrode 41 is a positive electrode or a negative electrode. The second electrode 42 is a negative electrode or a positive electrode.

[0018] Fig. 2 is a plan view of the solid-state battery 100 with the lid 30 removed. Fig. 3 is a perspective view of the package body 20.

[0019] 2, the battery element 40 has a circular shape in a plan view. However, the shape of the battery element 40 is not particularly limited, and may be, for example, rectangular in a plan view.

[0020] In this embodiment, the battery element 40 has a single cell structure including only one layer each of the first electrode 41, the solid electrolyte layer 43, and the second electrode 42. However, the battery element 40 may include a plurality of first electrodes 41, a plurality of solid electrolyte layers 43, and a plurality of second electrodes 42.

[0021] The first electrode 41 has a side surface 41p and an upper surface 41q. The side surface 41p is a surface (peripheral surface) located at an end of the first electrode 41 in a direction perpendicular to the stacking direction of the first electrode 41, the solid electrolyte layer 43, and the second electrode 42. The side surface 41p faces the inner side surface 20p of the package body 20. The upper surface 41q is a surface located at an end of the first electrode 41 in the stacking direction. The upper surface 41q faces the lid 30.

[0022] The current collecting member 60 includes a locking portion 60k that is locked to the package body 20, and is disposed along the side surface 41p of the first electrode 41 so as to surround the first electrode 41. In this way, the current collecting member 60 is electrically connected to the first electrode 41 of the battery element 40.

[0023] According to the solid-state battery 100 of this embodiment, power is extracted from the side surface 41p of the first electrode 41 of the battery element 40. Therefore, the structure of the solid-state battery 100 of this embodiment is suitable for improving the volumetric energy density of the solid-state battery 100 by increasing the thickness of the battery element 40 in the depth direction of the cavity CA of the ceramic package 10. Furthermore, the distance of the power supply path from the side surface 41p of the first electrode 41 of the battery element 40 to an external circuit board is shorter than the distance of the power supply path from the upper surface of the first electrode 41 of the battery element 40 to the external circuit board. Therefore, the solid-state battery 100 of this embodiment is likely to produce a large-current pulse output. In other words, the solid-state battery 100 of this embodiment is suitable for applications requiring large-current discharge.

[0024] The current collecting member 60 may be a plate-shaped member made of a metal material such as copper or nickel. The ratio R of the length of the connection surface between the first electrode 41 and the current collecting member 60 along the circumferential direction of the battery element 40 to the total circumferential length of the first electrode 41 along the circumferential direction of the battery element 40 is 60% or more. The ratio R may be 80% or more. In other words, most of the annular side surface 41p of the battery element 40 is in electrical contact with the current collecting member 60. This configuration is advantageous for the solid-state battery 100 to produce a large-current pulse output. The upper limit of the ratio R is not particularly limited and may be 100% or 90%.

[0025] 2, in this embodiment, the current collecting member 60 further includes a plurality of (two) locking portions 60k and a main body portion 60m. The locking portions 60k are located at both ends of the main body portion 60m. The main body portion 60m is located between the locking portions 60k. The current collecting member 60 contacts the first electrode 41 of the battery element 40 at the main body portion 60m.

[0026] In this embodiment, the current collecting member 60 is in contact only with the side surface 41p of the first electrode 41. In other words, the current collecting member 60 is not in contact with the upper surface 41q of the first electrode 41. This configuration is suitable for increasing the thickness of the battery element 40 and thereby improving the volumetric energy density of the solid-state battery 100.

[0027] In this embodiment, the current collecting member 60 has an annular or curved shape that surrounds the battery element 40. This configuration can improve the reliability of electrical contact between the current collecting member 60 and the first electrode 41. Note that the "annular shape" does not necessarily mean that the current collecting member 60 is in contact with the entire periphery of the battery element 40. For example, a C-shape or a U-shape is also included in the annular shape.

[0028] The width W of the current collecting member 60 in the thickness direction of the battery element 40 is less than the thickness of the first electrode 41. With this structure, it is possible to prevent electrical contact between the first electrode 41 and the second electrode 42 via the current collecting member 60. However, the width W of the current collecting member 60 may be equal to the thickness of the first electrode 41 or may be greater than the thickness of the first electrode 41.

[0029] The package body 20 includes a recess 22 and an internal terminal 24. The recess 22 is a portion for receiving the locking portion 60k of the current collecting member 60. The internal terminal 24 is provided so as to be exposed in the recess 22. The locking portion 60k of the current collecting member 60 is electrically connected to the internal terminal 24 in the recess 22. With this configuration, the first electrode 41 of the battery element 40 can be electrically connected to an external circuit board via the package body 20 and the current collecting member 60.

[0030] The sidewall 21 of the package body 20 includes a first portion 21a and a second portion 21b. The sidewall 21 is a frame-shaped portion surrounding the cavity CA in a plan view. The second portion 21b is thicker than the first portion 21a. The locking portion 60k of the current collecting member 60 is locked to the second portion 21b of the sidewall 21. That is, recesses 22 are provided in the second portion 21b. In this embodiment, the second portion 21b is a portion at each of the four corners. The first portion 21a is a portion located between the corners. This configuration prevents the strength of the ceramic package 10 from being insufficient due to the recesses 22. This is advantageous for improving the volumetric energy density of the solid-state battery 100. Note that in the plan view shown in FIG. 2 , the thickness of the sidewall 21 refers to the thickness in the radial direction of a circle centered on the center of gravity G of the cavity CA.

[0031] The package body 20 further includes via conductors 28a and external terminals 29a. The external terminals 29a are provided on the external bottom surface of the package body 20. The via conductors 28a extend through the package body 20 in the depth direction of the cavity CA to connect the internal terminals 24 and the external terminals 29a. The external terminals 29a are connected to the circuit board via solder. The external terminals 29a may be provided at multiple locations (for example, two locations) on the external bottom surface of the package body 20.

[0032] The package body 20 further includes a bottom terminal 25. The bottom terminal 25 is provided on the inner bottom surface 20b of the package body 20 so as to be in electrical contact with the second electrode 42. With this configuration, the second electrode 42 of the battery element 40 can be electrically connected to an external circuit board via the package body 20.

[0033] The package body 20 further includes via conductors 28b and external terminals 29b. The external terminals 29b are provided on the outer bottom surface of the package body 20. The via conductors 28b penetrate the bottom of the package body 20 to connect the bottom terminals 25 and the external terminals 29b. The external terminals 29b are connected to the circuit board via solder. The external terminals 29b may be provided at multiple locations (for example, two locations) on the outer bottom surface of the package body 20.

[0034] In this embodiment, the current collection path of the second electrode 42 of the battery element 40 is only the lower surface 42r of the second electrode 42. The side surface 42p of the second electrode 42 faces or contacts the inner side surface 20p of the package body 20. This configuration simplifies the electrical connection between an external circuit board and the second electrode 42 of the battery element 40.

[0035] The internal terminals 24, the bottom terminals 25, the via conductors 28a, 28b, the external terminals 29a, and the external terminals 29b are made of metal materials such as W, Mo, Cu, Ag, a Cu alloy, an Ag alloy, etc. The surfaces of the internal terminals 24, the bottom terminals 25, the external terminals 29a, and the external terminals 29b are plated with Ni and Au.

[0036] In this embodiment, a gap SH exists between the inner side surface 20p of the package body 20 and the battery element 40. Specifically, the gap SH exists between the inner side surface 20p of the package body 20 and the side surface of the battery element 40 at a position where the current collecting member 60 is not provided. With this configuration, the gap SH absorbs changes in the volume of the battery element 40 that occur with an increase in the ambient temperature of the solid-state battery 100 and / or changes in the volume of the battery element 40 that occur with charging and discharging of the battery element 40. This prevents large stresses from being applied to the ceramic package 10. As a result, the ceramic package 10 can be prevented from cracking. This is advantageous for reducing the thickness of the side wall portion 21 of the package body 20 and improving the volumetric energy density of the solid-state battery 100.

[0037] The package body 20 includes a current-carrying circuit for extracting power from the battery element 40 to the outside. In this embodiment, the current-carrying circuit is made up of the internal terminal 24, the bottom terminal 25, the via conductors 28a, 28b, the external terminals 29a, and the external terminals 29b. All of these elements may be located below the upper surface 41q of the first electrode 41.

[0038] For example, in the electrochemical element described in Patent Document 1, a conductive plate is disposed on the upper surface of a power generating element. The elastic locking portion of the conductive plate is inserted into an insertion hole in a recessed container. The connection portion between the elastic locking portion of the conductive plate and the conductor portion of the recessed container is partially located above the upper surface of the power generating element. With this configuration, when the conductive plate is pushed upward as the power generating element expands, a large moment may be applied to the recessed container by the conductive plate. Therefore, it is not easy to reduce the thickness of the recessed container to improve the volumetric energy density.

[0039] In contrast, according to the present embodiment, the entire current-carrying circuit of the package body 20 is located below the upper surface 41q of the first electrode 41. The connection portion between the current-carrying circuit and the current collecting member 60 is also located below the upper surface 41q of the first electrode 41. In this case, even if the battery element 40 expands, the moment applied from the current collecting member 60 to the package body 20 is smaller than in the structure of Patent Document 1. This prevents large stress from being applied to the ceramic package 10. As a result, the ceramic package 10 can be prevented from cracking. This is advantageous for reducing the thickness of the side wall portion 21 of the package body 20 and improving the volumetric energy density of the solid-state battery 100.

[0040] The thickness of the current collecting member 60 in the direction perpendicular to the stacking direction of the battery element 40 is equal to the dimension of the gap SH between the side surface of the battery element 40 and the inner side surface 20p of the package body 20 at a position where the current collecting member 60 is not present. In other words, the battery element 40 is fixed to the package body 20 via the current collecting member 60. With this configuration, the battery element 40 can be fixed to the package body 20 without using any other members.

[0041] The solid-state battery 100 further includes an insulating member 32 disposed between the lid body 30 and the first electrode 41. The insulating member 32 prevents contact between the battery element 40 and the lid body 30. In this embodiment, the insulating member 32 contacts both the lid body 30 and the battery element 40. In this case, the insulating member 32 functions to fix the battery element 40 to the ceramic package 10.

[0042] The Shore A hardness of the insulating member 32 is, for example, 80 or less. With this configuration, the insulating member 32 can absorb dimensional changes of the battery element 40 in the stacking direction. The lower limit of the Shore A hardness of the insulating member 32 is not particularly limited, and is, for example, 15. "Shore A hardness" refers to a value measured using a Type A durometer specified in Japanese Industrial Standards (JIS) K6253 (2012). If the thickness of the insulating member 32 is thinner than the specified thickness of the test specimen, a test specimen made of the same material as the insulating member 32 can be used for measurement.

[0043] The insulating member 32 can be made of a resin material such as urethane resin, fluororesin, silicone resin, polypropylene resin, polyethylene resin, etc. The insulating member 32 may have rubber elasticity.

[0044] The insulating member 32 may be omitted. In that case, only a space exists between the lid body 30 and the battery element 40.

[0045] In the battery element 40, when the first electrode 41 is a positive electrode, the first electrode 41 includes materials such as a positive electrode active material, a conductive material, a solid electrolyte, a binder, etc. When the second electrode 42 is a negative electrode, the second electrode 42 includes materials such as a negative electrode active material, a conductive material, a solid electrolyte, a binder, etc.

[0046] The positive electrode active material may be a material capable of absorbing and releasing metal ions, such as lithium ions. Examples of the positive electrode active material include lithium-containing transition metal oxides, lithium-containing transition metal phosphates, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal oxysulfides, and transition metal oxynitrides. Examples of the lithium-containing transition metal oxides include lithium cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, and lithium nickel manganese oxide. Examples of the lithium-containing transition metal phosphates include lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, and lithium nickel phosphate.

[0047] The negative electrode active material may be a material capable of absorbing and releasing metal ions such as lithium ions. Examples of the negative electrode active material include carbon materials and materials capable of forming alloys with metal ions. Examples of the carbon material include graphite. Examples of materials capable of forming alloys with lithium include silicon, silicon-containing oxides, tin, zinc alloys, bismuth, and germanium. One or more of these negative electrode active materials may be used alone or in combination.

[0048] Examples of conductive materials include carbon materials, conductive polymer compounds, etc. Examples of carbon materials include carbon black, graphite, acetylene black, carbon nanotubes, carbon nanofibers, graphene, fullerene, and graphite oxide. Examples of conductive polymer compounds include polyaniline, polypyrrole, and polythiophene.

[0049] Examples of binders include polymeric materials such as polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, polytetrafluoroethylene, carboxymethyl cellulose, polyacrylic acid, styrene-butadiene copolymer rubber, polypropylene, polyethylene, and polyimide.

[0050] Examples of the solid electrolyte include a halide solid electrolyte, a sulfide solid electrolyte, an oxide solid electrolyte, a polymer solid electrolyte, and a complex hydride solid electrolyte.

[0051] The solid electrolyte layer 43 is disposed between the first electrode 41 and the second electrode 42. Examples of the solid electrolyte contained in the solid electrolyte layer 43 include a halide solid electrolyte, a sulfide solid electrolyte, an oxide solid electrolyte, a polymer solid electrolyte, and a complex hydride solid electrolyte.

[0052] The first electrode 41 preferably includes an active material that expands during charging of the solid-state battery 100. Examples of such active materials include lithium cobalt oxide, lithium nickel cobalt manganese oxide having a nickel, cobalt, and manganese molar ratio of 2:7:1, and lithium nickel cobalt manganese oxide having a nickel, cobalt, and manganese molar ratio of 3:6:1. These active materials may contain small amounts of heterogeneous elements as long as the volume change during charging does not result in contraction. Among these, lithium cobalt oxide is preferable. This configuration can utilize the expansion of the first electrode 41 to strengthen the electrical connection between the first electrode 41 and the current collecting member 60. Furthermore, the expansion of the first electrode 41 can eliminate the gap between the current collecting member 60 and the inner side surface 20p of the package body 20. As a result, the battery element 40 can be fixed to the package body 20.

[0053] In this embodiment, the battery element 40 does not have a metal current collector. The first electrode 41 may be a compact of the positive electrode composite itself. The second electrode 42 may be a compact of the negative electrode composite itself. The solid electrolyte layer 43 may be a compact of the electrolyte composite itself. In the solid battery 100, the first electrode 41 is in direct contact with the current collecting member 60. The second electrode 42 is in direct contact with the bottom terminal 25. This configuration can improve the volumetric energy density of the solid battery 100. However, the first electrode 41 may have a metal current collector, and the second electrode 42 may have a metal current collector.

[0054] FIG. 4A is a plan view of a current collecting member 64 according to a modified example. FIG. 4B is a plan view of a current collecting member 66 according to another modified example. FIG. 4C is a plan view of a current collecting member 68 according to yet another modified example. In the modified example shown in FIG. 4A, the current collecting member 64 is divided into two portions 64c. Each of the two portions 64c includes a locking portion 60k. In the modified example shown in FIG. 4B, the current collecting member 66 is divided into four portions 66c. Each of the four portions 66c includes a locking portion 60k. In the modified example shown in FIG. 4C, the current collecting member 68 includes a completely annular main body portion 60m. With the current collecting member 68, the ratio R of the length of the connection surface between the first electrode 41 and the current collecting member 68 along the circumferential direction of the battery element 40 to the total circumferential length of the first electrode 41 along the circumferential direction of the battery element 40 can reach 100%. These current collecting members 64, 66 and 68 can be used in place of the current collecting member 60 shown in FIGS.

[0055] 5A is a cross-sectional view of a battery element 44 according to a modified example. In the battery element 44, a part or all of the side surface 42p of the second electrode 42 is covered with a solid electrolyte. In the battery element 44, the solid electrolyte layer 43 includes a first portion 43a and a second portion 43b. The first portion 43a is a portion located between the first electrode 41 and the second electrode 42. The second portion 43b is a portion covering the side surface 42p of the second electrode 42. This configuration is advantageous in preventing electrical contact between the first electrode 41 and the second electrode 42 via the current collecting member 60.

[0056] FIG. 5B is a cross-sectional view showing the state in which the current collecting member 60 is attached to the battery element 44 shown in FIG. 5A . In the example shown in FIG. 5B , the width W of the current collecting member 60 in the stacking direction of the battery element 44 is greater than the thickness W1 of the first electrode 41. This configuration is advantageous in increasing the area of ​​the connection surface between the first electrode 41 and the current collecting member 60. On the other hand, if the width W of the current collecting member 60 is large, there is a concern that the current collecting member 60 may come into contact with the second electrode 42. However, according to this modification, the side surface 42p of the second electrode 42 is covered with the second portion 43b made of a solid electrolyte. Therefore, even if the width W of the current collecting member 60 is large, electrical contact between the current collecting member 60 and the second electrode 42 is prevented.

[0057] (Embodiment 2) Fig. 6 is a cross-sectional view of a solid state battery 200 according to embodiment 2. Fig. 7 is a plan view of the solid state battery 200 according to embodiment 2 with the lid 30 removed.

[0058] The solid-state battery 200 further includes a current collecting member 70. Similar to the current collecting member 60 (first current collecting member) described in the first embodiment, the current collecting member 70 (second current collecting member) is a member for electrically connecting the ceramic package 10 and the battery element 40. The current collecting member 70 includes a locking portion 70k that is locked to the package body 20, and is disposed along the side surface 42p of the second electrode 42 so as to surround the second electrode 42. In this way, the current collecting member 70 is electrically connected to the second electrode 42 of the battery element 40.

[0059] The package body 20 includes a recess 23 and an internal terminal 26. The recess 23 is a portion for receiving the locking portion 70k of the current collecting member 70. The internal terminal 26 is provided so as to be exposed in the recess 23. The locking portion 70k of the current collecting member 70 is electrically connected to the internal terminal 26 in the recess 23. With this configuration, the second electrode 42 of the battery element 40 can be electrically connected to an external circuit board via the package body 20 and the current collecting member 70.

[0060] The locking portion 70k of the current collecting member 70 is locked to the second portion 21b of the side wall portion 21. That is, the second portion 21b is provided with a recess 23. The recess 23 is located diagonally from the recess 22.

[0061] In the package body 20, the via conductor 28b extends in the depth direction of the cavity CA through the package body 20 so as to connect the internal terminal 26 and the external terminal 29b. The external terminal 29b is connected to the circuit board via solder.

[0062] As described above, the configuration of the current collecting member 70 is the same as the configuration of the current collecting member 60 described in the first embodiment, except that the current collecting member 70 is attached to the second electrode 42. Therefore, the description of the current collecting member 60 can be applied to the current collecting member 70. The current collecting member 70 may be a component common to the current collecting member 60.

[0063] In this embodiment, the second electrode 42 is connected to an external circuit board only through the current collecting member 70. That is, according to this embodiment, the bottom terminal 25 described in the first embodiment can be omitted. However, the bottom terminal 25 may be provided on the package body 20.

[0064] In this embodiment, the thickness of the current collecting member 70 in the direction perpendicular to the stacking direction of the battery element 40 is equal to the dimension of the gap SH between the side surface of the battery element 40 and the inner side surface 20p of the package body 20 at a position where the current collecting member 70 is not present. In other words, the battery element 40 is fixed to the package body 20 via the current collecting member 70. In other words, according to this embodiment, the battery element 40 is fixed to the package body 20 via the current collecting member 60 and the current collecting member 70. With this configuration, the battery element 40 can be fixed to the package body 20 more reliably.

[0065] (Other Embodiments) (Additional Notes) The above description of the embodiments discloses the following techniques.

[0066] (Technology 1) A solid-state battery comprising: a ceramic package including a package body and a lid; a battery element including a first electrode, a solid electrolyte layer, and a second electrode, the battery element being housed in the ceramic package such that the first electrode, the solid electrolyte layer, and the second electrode are arranged in this order from the lid side toward the inner bottom surface of the package body; and a current collecting member including a locking portion locked to the package body, disposed along a side surface of the first electrode so as to surround the first electrode, and electrically connected to the first electrode.

[0067] According to the present disclosure, it is possible to provide a solid-state battery that is suitable for improving volumetric energy density and for use in large current discharge applications.

[0068] (Technology 2) The solid-state battery according to Technology 1, wherein a ratio of a length of a connection surface between the first electrode and the current collecting member along the circumferential direction of the battery element to an entire circumferential length of the first electrode along the circumferential direction of the battery element is 80% or more. Such a configuration is advantageous for the solid-state battery to produce a large current pulse output.

[0069] (Technology 3) The solid-state battery according to Technology 1 or 2, wherein the current collecting member is in contact with only the side surface of the first electrode. Such a configuration is suitable for increasing the volumetric energy density of the solid-state battery by increasing the thickness of the battery element.

[0070] (Technology 4) The solid-state battery according to any one of Technologies 1 to 3, wherein the current collecting member has an annular shape surrounding the battery element. With this configuration, it is possible to improve the reliability of electrical contact between the current collecting member and the first electrode.

[0071] (Technology 5) The solid-state battery according to any one of Technologies 1 to 4, wherein the package body includes a recess for receiving the locking portion of the current collecting member and an internal terminal exposed in the recess, and the locking portion of the current collecting member is electrically connected to the internal terminal in the recess. With this configuration, a first electrode of the battery element can be electrically connected to an external circuit board via the package body and the current collecting member.

[0072] (Technology 6) The solid-state battery according to any one of Technologies 1 to 5, wherein the side wall portion of the package body includes a first portion and a second portion thicker than the first portion, and the locking portion of the current collecting member is locked to the second portion of the side wall portion. With this configuration, it is possible to avoid a decrease in strength of the ceramic package due to a recess.

[0073] (Technology 7) The solid-state battery according to any one of Technologies 1 to 6, wherein a gap exists between the inner side surface of the package body and the battery element. With this configuration, a change in volume of the battery element due to an increase in the ambient temperature of the solid-state battery and / or a change in volume of the battery element due to charging and discharging of the battery element is absorbed by the gap SH.

[0074] (Technology 8) The solid-state battery according to any one of Technologies 1 to 7, wherein the current collection path of the second electrode is only on the underside of the second electrode. With this configuration, it is possible to simplify the electrical connection between an external circuit board and the second electrode of the battery element.

[0075] (Technology 9) The solid-state battery according to any one of Technologies 1 to 8, wherein the package body includes a current-carrying circuit for extracting power from the battery element to the outside, and the current-carrying circuit is entirely located below an upper surface of the first electrode. With this configuration, it is possible to avoid application of large stress to the ceramic package.

[0076] (Technology 10) The solid-state battery according to any one of Technologies 1 to 9, wherein the package body includes a bottom terminal provided on the inner bottom surface so as to be in electrical contact with the second electrode. With this configuration, the second electrode of the battery element can be electrically connected to an external circuit board via the package body.

[0077] (Technology 11) The solid-state battery according to any one of Technologies 1 to 10, further comprising an insulating member disposed between the lid and the first electrode. The insulating member can prevent contact between the battery element and the lid.

[0078] (Technology 12) The solid state battery according to Technology 11, wherein the insulating member has a Shore A hardness of not more than 80. With this configuration, the insulating member can absorb dimensional changes of the battery elements in the stacking direction.

[0079] (Technology 13) The solid-state battery according to any one of Technologies 1 to 12, wherein the first electrode includes an active material that expands when the solid-state battery is charged. With this configuration, the expansion of the first electrode can be utilized to strengthen the electrical connection between the first electrode and the current collecting member.

[0080] (Technology 14) The solid-state battery according to Technology 13, wherein the active material includes lithium cobalt oxide. With this configuration, the expansion of the first electrode can be utilized to strengthen the electrical connection between the first electrode and the current collecting member.

[0081] (Technology 15) The solid-state battery according to any one of Technologies 1 to 14, wherein a part or all of a side surface of the second electrode is covered with a solid electrolyte. Such a configuration is advantageous in preventing electrical contact between the first electrode and the second electrode via the current collecting member.

[0082] The techniques of the present disclosure are useful in solid-state batteries.

[0083] 10 Ceramic package 20 Package body 20b Inner bottom surface 20p Inner side surface 21 Side wall portion 21a First portion 21b Second portion 22, 23 Recess 24, 26 Internal terminal 25 Bottom terminal 28a, 28b Via conductor 29a, 29b External terminal 30 Lid 32 Insulating member 40, 44 Battery element 41 First electrode 41p, 42p Side surface 41q Top surface 42 Second electrode 42r Bottom surface 43 Solid electrolyte layer 43a First portion 43b Second portion 60, 64, 66, 68, 70 Current collecting member 64c, 66c Portion 60k, 70k Locking portion 60m Main body 100, 200 Solid-state battery CA Cavity SH Gap G center of gravity

Claims

1. A solid-state battery comprising: a ceramic package including a package body and a lid; a battery element including a first electrode, a solid electrolyte layer, and a second electrode, the battery element being housed in the ceramic package such that the first electrode, the solid electrolyte layer, and the second electrode are arranged in this order from the lid side toward the inner bottom surface of the package body; and a current collecting member including a locking portion locked to the package body, disposed along a side surface of the first electrode so as to surround the first electrode, and electrically connected to the first electrode.

2. The solid-state battery according to claim 1, wherein the ratio of the length of the connection surface between the first electrode and the current collecting member along the circumferential direction of the battery element to the total circumferential length of the first electrode along the circumferential direction of the battery element is 80% or more.

3. The solid-state battery according to claim 1, wherein the current collecting member is in contact only with the side surface of the first electrode.

4. The solid-state battery according to claim 1, wherein the current collecting member has an annular shape surrounding the battery element.

5. The solid-state battery according to claim 1, wherein the package body includes a recess for receiving the locking portion of the current collecting member and an internal terminal exposed in the recess, and the locking portion of the current collecting member is electrically connected to the internal terminal in the recess.

6. The solid-state battery according to claim 1, wherein the side wall of the package body includes a first portion and a second portion that is thicker than the first portion, and the locking portion of the current collecting member is locked to the second portion of the side wall.

7. The solid-state battery according to claim 1, wherein a gap exists between the inner side surface of the package body and the battery element.

8. The solid-state battery according to claim 1, wherein the current collection path of the second electrode is only on the lower surface of the second electrode.

9. The solid-state battery according to claim 1, wherein the package body includes a current-carrying circuit for extracting power from the battery element to the outside, and the current-carrying circuit is entirely located below the upper surface of the first electrode.

10. The solid-state battery according to claim 1, wherein the package body includes a bottom terminal provided on the inner bottom surface so as to be in electrical contact with the second electrode.

11. The solid-state battery according to claim 1, further comprising an insulating member disposed between the lid and the first electrode.

12. The solid-state battery according to claim 11, wherein the insulating member has a Shore A hardness of 80 or less.

13. The solid-state battery according to claim 1, wherein the first electrode includes an active material that expands when the solid-state battery is charged.

14. The solid-state battery according to claim 13, wherein the active material comprises lithium cobalt oxide.

15. The solid-state battery according to claim 1, wherein a part or all of the side surface of the second electrode is covered with a solid electrolyte.

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