Electronic device, cover for electronic device, and method for testing the airtightness of electronic device

Abstract

This invention provides an electronic device that allows for easy evaluation of the airtightness of a case, even if the case design changes. [Solution] The case 10 includes a container 11 having an opening and a plate-shaped lid 12 covering the opening, and a component 20 housed in a space sealed by the container 11 and the lid 12, wherein a window portion 121 is formed in the bottom of the container 11 or the lid 12, and the window portion 121 is thinner than the thickness of the bottom of the container or the lid excluding that portion.

Description

Technical Field

[0001] The present invention relates to an electronic device, a lid of the electronic device, and a method for inspecting the airtightness of the electronic device.

Background Art

[0002] Conventionally, various electronic devices such as electrochemical elements in which a power generation element or the like is housed in an internal space formed by a concave container and a lid covering the opening of the concave container have been disclosed. For example, International Publication No. 2022 / 030424 discloses a battery package including an insulating substrate having a recess, a frame portion surrounding the recess, and a lid closing the frame portion.

[0003] Some of the contents of electronic devices react with moisture in the air and deteriorate in characteristics. Therefore, high airtightness may be required for the containers of electronic devices. International Publication No. 2014 / 7215 discloses an all-solid-state secondary battery including a battery element body composed of a solid electrolyte, a positive electrode, and a negative electrode. This all-solid-state secondary battery includes a resin portion including at least two or more resin layers around the battery element body, and at least one of the resin layers of this resin portion is a layer having a lower water absorption rate than the other resin layers.

[0004] Although not related to electronic devices, Japanese Unexamined Patent Application Publication No. 2014-85246 discloses an internal pressure inspection device and an internal pressure inspection method for a sealed container that determines the quality of the internal pressure by measuring the deformation of the lid portion due to the internal pressure of the sealed container using a laser displacement sensor in a sealed container in which a body portion and a lid portion are connected by a connecting portion.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[0006] One possible method for testing the airtightness of an electronic device case is to use the immersion method (bombing method) specified in JIS Z 2331 (Helium Leakage Test Method). In this test method, the electronic device is first placed in a chamber, the chamber is evacuated, and then helium is filled into the chamber to create a pressurized helium atmosphere. If the airtightness of the electronic device case is insufficient at this time, helium will enter the case. The airtightness of the case can then be determined by whether or not helium is detected when the electronic device is moved to another chamber and this chamber is evacuated.

[0007] While this inspection method using a helium detector can accurately evaluate the airtightness of a case, it is time-consuming and therefore unsuitable for, for example, 100% inspection before product shipment.

[0008] The applicant has developed a method for manufacturing an electronic device that allows for easy evaluation of the airtightness of a case, and has filed a patent application for this manufacturing method (PCT / JP2024 / 032876). This method for manufacturing an electronic device comprises a sealing step of sealing a case under a reduced pressure environment, a measurement step of measuring the displacement of a predetermined measuring surface of the sealed case, and an evaluation step of evaluating the airtightness of the case based on the measured displacement.

[0009] When a case is sealed under reduced pressure, the internal pressure becomes lower than atmospheric pressure. Therefore, when the case is returned to an atmospheric pressure environment, it deforms due to the pressure of the air, resulting in an inward-facing concave shape. If the airtightness of the case is poor, air will flow into the case, eliminating the pressure difference between the inside and outside of the case, resulting in no concave shape or a smaller concave shape compared to a good case. In this way, the airtightness of a case can be easily evaluated based on the amount of displacement (size of the concave shape) of the case.

[0010] More specifically, it is conceivable to measure the displacement of a predetermined measuring surface immediately after sealing and at a predetermined time after sealing, and to distinguish between good and defective products based on the absolute value of the displacement at each point in time and the change in the displacement between the two points in time (the rate at which the displacement decreases). When performing this distinction, it is preferable to obtain data in advance from a large number of samples including good and defective products to determine the relationship between the displacement and the amount of leakage, and to establish standards for quality control. On the other hand, even if the pressure inside the case is the same, the manner in which the case deforms will differ depending on the material, shape, size, etc. of the case. Therefore, it is necessary to re-obtain the above data each time the material, shape, size, etc. of the case change.

[0011] The object of the present invention is to provide an electronic device, a lid for the electronic device, and a method for testing the airtightness of an electronic device that can easily evaluate the airtightness of a case even if the case design changes. [Means for solving the problem]

[0012] An electronic device according to one embodiment of the present invention comprises a case including a container having an opening and a plate-shaped lid covering the opening, and a component housed in a space sealed by the container and the lid, wherein a window portion is formed in the bottom of the container or the lid, the window portion being thinner than the thickness of the portion of the container or the lid excluding that portion.

[0013] The cover of an electronic device according to one embodiment of the present invention is the cover of the electronic device described above.

[0014] An airtightness testing method for an electronic device according to one embodiment of the present invention is an airtightness testing method for testing the airtightness of the above-mentioned electronic device, comprising the steps of: measuring the displacement of the window portion; and evaluating the airtightness of the case of the electronic device based on the displacement of the window portion. [Effects of the Invention]

[0015] According to the present invention, even if the design of the case changes, the airtightness of the case can be easily evaluated.

Brief Description of the Drawings

[0016] [Figure 1] Figure 1 is a perspective view schematically showing the configuration of a battery, which is an example of an electronic device according to the first embodiment of the present invention. [Figure 2] Figure 2 is an exploded perspective view of the battery in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of the lid along the line III-III in Figure 2. [Figure 4] Figure 4 is a cross-sectional view of a modified example of the lid. [Figure 5] Figure 5 is a cross-sectional view of another modified example of the lid. [Figure 6] Figure 6 is a cross-sectional view of the lid along the line VI-VI in Figure 1. [Figure 7] Figure 7 is a flowchart of an airtightness inspection method for inspecting the airtightness of the battery in Figure 1. [Figure 8] Figure 8 is a view showing an example of a battery provided with cases having different shapes and sizes. [Figure 9] Figure 9 is an exploded perspective view schematically showing the configuration of a battery according to a modified example. [Figure 10] Figure 10 is a perspective view of the battery in Figure 9 as seen from the bottom side. [Figure 11] Figure 11 is a cross-sectional view along the line XI-XI in Figure 10. [Figure 12] Figure 12 is a cross-sectional view of the lid included in an electronic device according to the second embodiment of the present invention, and is a cross-sectional view when there is no pressure difference between the front and back surfaces. [Figure 13] Figure 13 is a cross-sectional view of the lid included in an electronic device according to the second embodiment of the present invention, and is a cross-sectional view when there is a pressure difference between the front and back surfaces. [Figure 14] Figure 14 is a view schematically showing a situation where a compressive stress is generated inside a member in the case of an intermediate shape between Figure 12 and Figure 13.

Modes for Carrying Out the Invention

[0017] The embodiments of the present invention will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated. The dimensional ratios between the constituent members shown in each drawing do not necessarily represent the actual dimensional ratios.

[0018] [First Embodiment] [Electronic devices] An electronic device according to the first embodiment of the present invention is an electronic device comprising a case and components housed in the case. Examples of electronic devices include discrete components, semiconductors, sensors, integrated circuits, resistors, capacitors, coils, batteries, and capacitors. Among the electronic devices according to this embodiment, those in which the components housed inside are power generation elements are particularly preferred. Specific examples of such electronic devices include electrochemical elements such as lithium-ion batteries, lithium-ion capacitors, and electric double-layer capacitors.

[0019] The following explanation uses the example of an electronic device being a battery. Figure 1 is a schematic perspective view showing the configuration of a battery 1, which is an example of an electronic device. Figure 2 is an exploded perspective view of the battery 1. The battery 1 comprises a case 10 and a power generation element (component) 20. The case 10 has a container 11 with an opening 11a (Figure 2) and a plate-shaped lid 12 that covers the opening 11a. The power generation element 20 is housed in a space sealed by the container 11 and the lid 12.

[0020] The material of the container 11 is, for example, ceramic. The material of the lid 12 is, for example, metal. The container 11 and the lid 12 are fixed together by welding a metal seal ring 115 (Figure 2) formed around the opening 11a of the ceramic container 11 to the metal lid 12. With this configuration, even if the main body portion of the container 11 (the portion other than the seal ring 115) is non-metallic (ceramic), the container 11 and the lid 12 can be fixed together by welding.

[0021] This configuration is just one example, and any method of fixing the container 11 and the lid 12 can be used as long as it can create an airtight seal inside. Furthermore, the materials of the container 11 and the lid 12 are not limited to the above combination (container 11 is ceramic, lid 12 is metal).

[0022] The container 11 can be any material that can ensure a predetermined level of airtightness, and may be made of metal, resin, glass, or the like. If the material of the container 11 is a conductor such as metal, an insulator or the like may be placed between the container 11 and the power generation element 20. However, from the viewpoint of airtightness and insulation, it is preferable to use ceramic for the container 11.

[0023] The lid 12, like the container 11, only needs to be able to ensure a predetermined level of airtightness, and may be made of ceramic, resin, glass, or the like. It is preferable that the lid 12 is elastically deformable. For this reason, the material of the lid 12 is preferably metal or resin, particularly preferably metal, and especially preferably Fe-Ni alloy or Fe-Ni-Co alloy, which have a small difference in thermal expansion coefficient with ceramic.

[0024] It is preferable that the container 11 has higher rigidity than the lid 12. For example, it is preferable that the container 11 is made of a material with a higher Young's modulus than the lid 12. Alternatively, it is preferable that the thickness of the walls and bottom of the container 11 is greater than the thickness of the lid 12. As will be described later, it is preferable that the container 11 hardly deforms when the pressure inside the space sealed by the container 11 and the lid 12 is reduced to less than atmospheric pressure.

[0025] As shown in Figure 2, the power generation element 20 is a laminate comprising a positive electrode layer 21, a negative electrode layer 22, and a solid electrolyte layer 23 disposed between the positive electrode layer 21 and the negative electrode layer 22. In other words, this battery 1 is a so-called all-solid-state battery. The types of the positive electrode layer 21, the negative electrode layer 22, and the solid electrolyte layer 23 are not particularly limited, and any known material can be used as the material for each.

[0026] Although not shown in Figure 1, the battery 1 may also include terminals for drawing current, lead members for connecting the terminals to the power generation element 20, and fixing members (spacers) for fixing the power generation element 20. The battery 1 can adopt any known configuration for these components.

[0027] Battery 1 is assembled in a reduced-pressure environment, i.e., a vacuum-evacuated environment. Specifically, it is manufactured by performing a sealing process in which the container 11 and the lid 12 are fixed together with the power generation element 20 placed inside the container 11 under reduced-pressure conditions. Therefore, in Battery 1, the pressure inside the space sealed by the container 11 and the lid 12 (hereinafter referred to as the "internal space") is lower than atmospheric pressure. Sealing under reduced-pressure conditions can be performed, for example, by a seam welding apparatus equipped with a vacuum chamber. The degree of vacuum during sealing is not particularly limited, but for example, 10 -1 Pa or less, preferably 10 -2 The vacuum level should be less than or equal to Pa. It is preferable to keep the vacuum level as consistent as possible each time during sealing.

[0028] The internal pressure of the interior space is not limited to this, but for example, 10 -1 Pa or less, preferably 10 -2 It is below Pa.

[0029] [12 Lid Shapes] Figure 3 is a cross-sectional view of the lid 12 along the line III-III in Figure 2, and is an enlarged cross-sectional view showing the vicinity of the window portion 121, which will be described later. Figure 3 illustrates the case where the pressure applied to the front and back surfaces of the lid 12 is the same. In other words, Figure 3 shows the shape of the lid 12 before the battery 1 is assembled.

[0030] The lid 12 has a plate-like shape. The lid 12 is preferably flat, but may also have a gently curved shape. Except for the window portion 121 described below, the lid 12 is preferably of a generally uniform thickness.

[0031] The lid 12 has a window portion 121 formed in it, which is thinner than the thickness of the lid 12 excluding the window portion 121. Hereinafter, the portion of the lid 12 other than the window portion 121 will be referred to as the remaining portion 122.

[0032] The window portion 121 and the remaining portion 122 may be made of different materials, but it is preferable that they be made of the same material. In other words, it is preferable that the lid 12, including the window portion 121, be made of a single material.

[0033] As shown in Figure 3, the window portion 121 is preferably planar in shape when the pressure applied to its front and back surfaces is the same. More specifically, the window portion 121 is preferably on the same plane as the remaining portion 122 (more precisely, the front and back surfaces of the window portion 121 are on the same plane as or inside the front and back surfaces of the remaining portion 122) and is parallel to the remaining portion 122 when the pressure applied to its front and back surfaces is the same.

[0034] Figure 3 illustrates a case where the lid 12 has a recess formed on the side opposite to the side facing the container 11 (i.e., the side opposite to the internal space side), thereby forming a window portion 121 that is thinner than the remaining portion 122. This configuration is illustrative, and the lid may also be configured such that, for example, as shown in Figure 4, lid 12A has a recess formed on the side facing the container 11 (i.e., the side facing the internal space), thereby forming a window portion 121A that is thinner than the remaining portion 122A. Alternatively, the lid may be configured such that, as shown in Figure 5, lid 12B has recesses formed on both the front and back surfaces, thereby forming a window portion 121B that is thinner than the remaining portion 122B. With the configurations of lid 12 (Figure 3) and lid 12B (Figure 5), the window portion (window portion 121 or window portion 121B) can be easily seen from the outside. On the other hand, when the lid 12A (Figure 4) is configured, the window portion (window portion 121A) can be made less conspicuous, which is an advantage.

[0035] In all cases shown in Figures 3 to 5, it is preferable that the thickness t of the window portion (window portion 121, 121A, or 121B) is constant. If there is variation in the thickness t of the window portion, the measurement error of the "displacement amount" described later will increase.

[0036] Figure 6 is a cross-sectional view of the lid 12 along the line VI-VI in Figure 1, showing an enlarged view of the vicinity of the window portion 121. Unlike Figure 3, Figure 6 is a cross-sectional view showing the shape of the lid 12 in the assembled state of the battery 1.

[0037] As previously described, in battery 1, the internal pressure is lower than atmospheric pressure. Therefore, when battery 1 is placed in an atmospheric pressure environment, the lid 12 is subjected to a load in the direction toward the internal space. At this time, since the thickness of the window portion 121 is thinner than the thickness of the remaining portion 122, the window portion 121 deforms more than the remaining portion 122.

[0038] When the battery 1 is assembled, that is, when the pressure inside the internal space is less than the pressure outside the internal space, the window portion 121 takes on a recessed shape toward the internal space. More specifically, as shown in Figure 6, the window portion 121 takes on a recessed shape such that the amount of displacement toward the internal space increases as you approach the center of the window portion 121 in the in-plane direction of the lid 12 (in other words, as you move away from the remaining portion 122).

[0039] [Method for testing the airtightness of electronic devices] Next, using the case of inspecting the airtightness of battery 1 as an example, a method for inspecting the airtightness of an electronic device according to one embodiment of the present invention will be described. Figure 7 is a flowchart of the airtightness inspection method for inspecting the airtightness of battery 1. This airtightness inspection method comprises a step of measuring the displacement of the window portion 121 (step S1) and a step of evaluating the airtightness of case 10 (Figure 1) based on the displacement of the window portion 121 (step S2).

[0040] First, the displacement of the window portion 121 is measured (step S1). This measurement may be performed immediately after assembling the battery 1 (immediately after sealing the opening 11a of the container 11), or it may be performed after a predetermined period of time has elapsed since assembling the battery 1. It is preferable to perform this measurement at multiple points in time, and it is also preferable to record the displacement at each point in time.

[0041] As previously described, since battery 1 is assembled in a reduced-pressure environment, immediately after sealing, the pressure inside the internal space is lower than atmospheric pressure. When battery 1 is returned to an atmospheric pressure environment, the window portion 121 receives a load in the direction toward the internal space and deforms into a concave shape toward the internal space (shape shown in Figure 6).

[0042] The "displacement amount" is a value (index) that represents the magnitude of deformation of the window portion 121. The "displacement amount" can be any amount that correlates with the magnitude of deformation of the window portion 121. For example, the "displacement amount" can be the amount of deformation from the reference shape at the center of the window portion 121 in the in-plane direction (depth of the indentation at the center position), with the shape of the window portion 121 before deformation (shape in Figure 3) as the reference shape. Alternatively, the "displacement amount" may be the amount of deformation that is greatest from the reference plane (maximum depth of the indentation).

[0043] The "displacement amount" may also be defined as the volume of the recessed portion of the window 121. Specifically, the shape of the window 121 before deformation can be used as the reference shape, and the volume of the area enclosed by the reference shape and the recessed window 121 can be defined as the "displacement amount." By defining the volume of the recessed portion of the window 121 as the "displacement amount," information from a wide range of the measurement surface is reflected in the "displacement amount," thus reducing the variability of the measurement results. The volume of the recessed portion of the window 121 can be determined, for example, by measuring the three-dimensional shape of the window 121 using an optical displacement meter. As an optical displacement meter, for example, the white light interferometry 3D displacement meter "WI-5000" manufactured by Keyence Corporation can be used.

[0044] Furthermore, instead of using the shape of the window portion 121 before deformation as the reference shape when determining the "amount of displacement," a plane passing through the four corners or periphery of the window portion 121, or a plane passing through the four corners or periphery of the lid 12, may be used as the reference shape. Alternatively, the three-dimensional shape of the part of the lid 12 other than the window portion 121 (i.e., the remaining portion 122) may be measured using an optical displacement meter, and the plane that conforms to the shape of the remaining portion 122 may be determined by the least squares method or the like and used as the reference shape. When determining the reference shape based on the shape of the remaining portion 122, it is preferable that the thickness of the remaining portion 122 is constant, as variations in the thickness of the remaining portion 122 may increase the measurement error of the amount of displacement. Also, from the viewpoint of suppressing the effects of variations in the thickness of the window portion 121 and the remaining portion 122, it is preferable to use a plane passing through the four corners of the window portion 121 as the reference shape.

[0045] Next, the airtightness of the case 10 is evaluated based on the displacement of the window portion 121 (step S2). As previously described, immediately after sealing, the window portion 121 takes on a recessed shape toward the internal space (shape shown in Figure 6). On the other hand, if the airtightness of the case 10 is very poor, for example, if there is a large faulty joint at the joint between the container 11 and the lid 12, air will flow into the case 10 from this point, and the pressure difference between the inside and outside of the case 10 will disappear. As a result, the window portion 121 will not take on a recessed shape toward the internal space, or the size of the recess (displacement) will be smaller compared to a good product.

[0046] Even if there is a faulty joint between the container 11 and the lid 12, if the fault is small and the amount of air inflow is small, the pressure difference between the inside and outside of the case 10 will be maintained for a while after sealing, so the displacement of the window 121 will be about the same as that of a good product. Even in this case, if there is air inflow, the pressure difference will gradually decrease over time, so the displacement will gradually decrease. Usually, the larger the amount of air inflow, the greater the change in displacement (the rate at which the displacement decreases). However, if the amount of air inflow becomes large enough, the pressure difference will disappear at an early stage, so the change in displacement will become small again.

[0047] In this way, the airtightness of Case 10 can be evaluated by evaluating the absolute value of the displacement of the window portion 121 and the change in the displacement. It is preferable to evaluate the airtightness of Case 10 by combining evaluation based on the absolute value of the displacement and evaluation based on the change in the displacement.

[0048] When evaluating the airtightness of case 10, it is preferable to obtain data in advance from a large number of samples, including good and defective products, to determine the relationship between displacement and leakage, and to establish standards for quality control. For example, the displacement of the window portion 121 may be measured for a large number of samples, and the airtightness of case 10 of these samples may be quantitatively measured by the immersion method (bombing method), and the relationship between the displacement of the window portion 121 and the airtightness of case 10 may be obtained. Based on this relationship, for example, a threshold value for the absolute value of the displacement or the change in the displacement when the absolute value of the leakage exceeds a predetermined amount may be determined to distinguish between good and defective products.

[0049] [Effects of this embodiment, etc.] According to the configuration of battery 1, the airtightness of case 10 can be easily evaluated by measuring the displacement of window portion 121.

[0050] As described above, when evaluating the airtightness of case 10, it is preferable to obtain data in advance from a large number of samples, including good and defective products, to determine the relationship between displacement and leakage, and to establish standards for quality control. On the other hand, even if the internal pressure of case 10 is the same, the manner in which case 10 deforms will differ depending on the material, shape, size, etc. of the case. Therefore, it is necessary to obtain the above data again each time the material, shape, size, etc. of the case change.

[0051] In the configuration of battery 1, a window portion 121 is formed in the lid 12, which is a thinner portion than the remaining portion 122. With this configuration, if the material, shape, and size of the window portion 121 are kept constant, the airtightness of cases 10 of various materials, shapes, and sizes can be evaluated using the relationship between the displacement amount of the window portion 121 (absolute value of the displacement amount and / or change in the displacement amount) and the amount of leak, etc., measured once. In other words, if the material, shape, and size of the window portion 121 are kept constant, and the degree of vacuum during sealing is kept constant each time, the airtightness of the case 10 can be evaluated based on the relationship between the displacement amount of the window portion 121 and the amount of leak, etc., measured once, even if the material, shape, size, etc., of the container 11 and the lid 12 (remaining portion 122) are changed.

[0052] For example, as shown in Figures 8(a) to (d), even if the shape and size of the container 11 and the lid 12 are changed, the airtightness of the case 10 can be evaluated using the same criteria as long as the material, shape, and size of the window portion 121 remain constant.

[0053] However, if the shape or size of the container 11 and lid 12 is changed, or if the vacuum equipment is updated, it is preferable to check whether the displacement of the window portion 121 is the same before and after the change.

[0054] Furthermore, the portion of the lid 12 excluding the window portion 121 (the remaining portion 122) also deforms to some extent due to the pressure difference between the inside and outside of the internal space. The effect of the deformation of the remaining portion 122 can be corrected, for example, by measuring the three-dimensional shape of the remaining portion 122 with an optical displacement meter, determining a plane that conforms to the shape of the remaining portion 122 using the least squares method or the like as a reference shape, and then determining the displacement of the window portion 121 from this reference plane. When determining the reference shape, if there is variation in the thickness of the remaining portion 122, the measurement error may increase, so it is preferable that the thickness of the remaining portion 122 is constant. Alternatively, the deformation of the remaining portion 122 can be less affected by the deformation of the remaining portion 122 by determining the displacement using a plane passing through the four corners of the window portion 121 as the reference shape. However, it is preferable that the deformation of the remaining portion 122 be small, and more preferably that it be negligible compared to the deformation of the window portion 121.

[0055] The thickness t of the window portion 121 (see Figure 3) is preferably 0.05 to 0.15 mm. The thinner the thickness t, the greater the displacement, making it easier to test for airtightness. On the other hand, if the thickness t is too thin, it becomes difficult to process. Also, if the thickness t is too thin, the displacement may become too large, causing it to come into contact with internal components, compress them, or cause malfunctions in the circuit. The lower limit of the thickness t is more preferably 0.06 mm. The upper limit of the thickness t is more preferably 0.10 mm. Note that the thickness t of the window portion 121 is the average thickness of the window portion 121.

[0056] The thickness T of the portion of the lid 12 excluding the window portion 121 (the remaining portion 122) (see Figure 3) is preferably 0.05 to 1.00 mm. As described above, it is preferable that the remaining portion 122 is not easily deformed by the pressure difference between the inside and outside of the internal space, and therefore a certain degree of thickness T is preferable. On the other hand, if the thickness T is too large, welding defects may occur depending on the structure of the case 10. Also, if the thickness T is too large, the internal space (capacity) may decrease depending on the structure of the case 10. The lower limit of the thickness T is more preferably 0.10 mm, even more preferably 0.20 mm, and even more preferably 0.30 mm. The upper limit of the thickness T is more preferably 0.80 mm, even more preferably 0.60 mm, and even more preferably 0.40 mm. The thickness T of the remaining portion 122 is the average thickness of the remaining portion 122.

[0057] The thickness t is preferably 5 to 70% of the thickness T. The lower limit of the thickness t is more preferably 10% of the thickness T, and even more preferably 20%. The upper limit of the thickness t is more preferably 50% of the thickness T, and even more preferably 40%.

[0058] The area of ​​the window section 121 is preferably 9 to 225 mm². 2 If the area of ​​the window portion 121 is too large, it will not be possible to provide the window portion 121 in the small lid 12. On the other hand, if the area of ​​the window portion 121 is too small, the amount of deformation will be small, making it difficult to test for airtightness. The lower limit of the area of ​​the window portion 121 is preferably 36 mm.2 The upper limit of the area of ​​the window portion 121 is more preferably 100 mm². 2 That is the case.

[0059] Figures 1, 2, and 8 illustrate the case where the planar shape of the window section 121 is rectangular, but the window section 121 may have any planar shape. However, in order to ensure that the load is applied uniformly, it is preferable that the planar shape of the window section 121 be a highly symmetrical shape (square or circular). For example, if the planar shape of the window section 121 is square, the dimensions of the window section 121 may be 3 mm × 3 mm to 15 mm × 15 mm.

[0060] The area of ​​the window portion 121 is preferably 50% or less of the area of ​​the lid 12. The lower limit of the area of ​​the window portion 121 is not particularly limited, but may be, for example, 1%, 5%, or 10% of the area of ​​the lid 12. The upper limit of the area of ​​the window portion 121 is preferably 40% of the area of ​​the lid 12.

[0061] The above describes battery 1, the lid 12 of the battery 1 case 10, and the method for testing the airtightness of battery 1. In the above description, battery 1, which is an all-solid-state battery, was described as an example of an electronic device, but the above configuration is also applicable to electronic devices other than batteries. The electronic device according to this embodiment comprises a case including a container having an opening and a plate-shaped lid that covers the opening, and a component housed in a space sealed by the container and the lid, wherein the lid has a window portion formed therein, which is a portion thinner than the thickness of the lid excluding that portion (window portion). According to this embodiment, the airtightness of the case can be easily evaluated even if the design of the case changes.

[0062] The electronic device according to this embodiment is preferably an electrochemical element equipped with a power generation element. The electronic device according to this embodiment is suitable when the electronic device is equipped with a solid electrolyte, and is particularly suitable when it is equipped with a sulfide-based solid electrolyte.

[0063] The above description describes the case in which a window portion 121 is formed on the lid 12, but instead, the window portion may be formed on the bottom of the container 11. That is, the electronic device according to this embodiment may include a case that includes a container having an opening and a plate-shaped lid that covers the opening, and a component housed in a space sealed by the container and the lid, wherein a window portion is formed on the bottom of the container, and the window portion is a portion that is thinner than the thickness of the bottom of the container excluding that portion (the window portion).

[0064] Figure 9 is an exploded perspective view schematically showing the configuration of battery 1D according to a modification of this embodiment. Like battery 1 (Figure 1), battery 1D also comprises a case 10 and a power generation element 20. The case 10 has a container 11 having an opening 11a and a plate-shaped lid 12 that covers the opening 11a. The lid 12 may have hermetic terminals. The power generation element 20 is housed in a space sealed by the container 11 and the lid 12. In battery 1D, for example, the inner circumference of the opening 11a of the container 11 and the outer circumference of the lid 12 are sealed by laser welding.

[0065] The container 11 of battery 1D has a plate-shaped bottom 11b. Figure 10 is a perspective view of battery 1D seen from the bottom 11b side, and Figure 11 is a cross-sectional view along the line XI-XI in Figure 10. In battery 1D, a window portion 111 is formed in the bottom 11b of the container 11, which is thinner than the portion 112 of the bottom 11b of the container 11 excluding that portion. With this configuration, as in the case of battery 1 (Figure 1), the airtightness of the case can be easily evaluated even if the case design changes.

[0066] In other words, the electronic device according to this embodiment comprises a case including a container having an opening and a plate-shaped lid covering the opening, and a component housed in a space sealed by the container and the lid, wherein a window portion is formed on the bottom of the container or the lid, and the window portion is thinner than the thickness of the portion of the container or lid excluding the window portion.

[0067] [Second Embodiment] The electronic device according to the second embodiment of the present invention differs from the electronic device according to the first embodiment (battery 1 (Figure 1, etc.)) in the configuration of the cover. The battery device according to this embodiment is equipped with a cover 13 shown in Figures 12 and 13 instead of the cover 12 of battery 1. The cover 13 also has a window portion 131, which is thinner than the thickness of the part of the cover 13 excluding that portion (window portion 131), similar to the case of the cover 12. Figure 12 is a schematic cross-sectional view showing the shape of the cover 13 when the magnitude of the pressure applied to the front and back surfaces of the window portion 131 is the same, and Figure 13 is a schematic cross-sectional view showing the shape of the cover 13 when the pressure inside the internal space is smaller than the pressure outside the internal space, and there is a pressure difference of a predetermined magnitude or more.

[0068] When the magnitude of the pressure applied to the front and back surfaces of the window portion 131 is the same, the window portion 131 has a shape that bulges toward one side of the front and back surfaces, as shown in Figure 12. More specifically, the window portion 131 has a shape that bulges such that the amount of displacement increases as it approaches the center of the window portion 131 in the in-plane direction of the lid 13. In the electronic device according to this embodiment, the lid 13 is positioned so that the bulging side of the window portion 131 is on the outside of the space (internal space) sealed by the container (not shown) and the lid 13.

[0069] When the pressure inside the internal space is less than the pressure outside the internal space, and the pressure difference is greater than a predetermined amount, the window portion 131 deforms under pressure from the pressure outside the internal space (atmospheric pressure), and as shown in Figure 13, it takes on a concave shape toward the inside of the internal space. More specifically, the window portion 131 becomes concave in such a way that the amount of displacement toward the internal space increases as it approaches the center of the window portion 131 in the in-plane direction of the lid 13.

[0070] When the pressure difference between the inside and outside of the internal space decreases from the state in which the window portion 131 is in the shape shown in Figure 13 to below a predetermined value, the window portion 131 deforms back to the shape shown in Figure 12. Here, in an intermediate shape between Figure 12 and Figure 13 (for example, the shape shown in Figure 14), compressive stress is generated inside the window portion 131, so the window portion 131 will attempt to deform into either the shape shown in Figure 12 or Figure 13. Therefore, the window portion 131 takes the shape shown in Figure 13 when the pressure difference between the inside and outside of the internal space is greater than or equal to a predetermined value, and takes the shape shown in Figure 12 when the pressure difference between the inside and outside of the internal space is less than a predetermined value.

[0071] In other words, if the window portion 131 has the shape shown in Figure 13, the airtightness of the case is good, and the pressure difference between the inside and outside of the internal space is maintained at or above a predetermined size. On the other hand, if the window portion 131 has the shape shown in Figure 12, the airtightness of the case is poor, and the pressure difference between the inside and outside of the internal space is below a predetermined size. Thus, according to this embodiment, the airtightness of the case can be evaluated based on the shape of the window portion 131.

[0072] When the magnitude of the pressure applied to the front and back surfaces of the window portion 131 is the same, the protrusion amount h of the window portion 131 is preferably 0.01 mm or more. Here, "protrusion amount h" is the dimension along the thickness direction of the window portion 131 between the peripheral edge of the window portion 131 (the part in contact with the remaining portion 132) and the part of the window portion 131 that protrudes the most. Increasing the protrusion amount h makes the condition of the window portion 131 easier to see. The lower limit of the protrusion amount h is more preferably 0.03 mm or more, and even more preferably 0.06 mm. The upper limit of the protrusion amount h is, for example, 1.0 mm, and preferably 0.5 mm.

[0073] The electronic device according to the second embodiment of the present invention has been described above. With this embodiment as well, the airtightness of the case can be easily evaluated regardless of the case design. In the above description, the case in which a window portion 131 is formed on the lid 13 was described, but instead, a window portion similar to the window portion 131 may be formed on the bottom of the container 11.

[0074] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the invention. [Explanation of Symbols]

[0075] 1 Battery (electronic device), 10 Case, 11 Container, 111 Window section, 112 Remaining parts, 115 Seal ring, 12,13 Lid, 121,131 Window section, 122,132 Remaining parts, 20 Power generation element (component), 21 Positive electrode layer, 22 Negative electrode layer, 23 Solid electrolyte layer

Claims

1. A case including a container having an opening and a plate-shaped lid that covers the opening, The container comprises a component housed in a space sealed by the container and the lid, An electronic device having a window portion formed in the bottom of the container or the lid, which is thinner than the thickness of the portion of the container or the lid excluding that portion.

2. The electronic device according to claim 1, wherein the pressure inside the space is less than atmospheric pressure.

3. The electronic device according to claim 1, wherein the window portion has a planar shape when the pressure applied to the front and back surfaces is the same, and has a recessed shape toward the inside of the space when the pressure inside the space is less than the pressure outside the space.

4. The electronic device according to claim 1, wherein the window portion has a shape that bulges outward from the space when the pressure applied to the front and back surfaces is the same magnitude, and has a shape that recesses inward from the space when the pressure inside the space is less than the pressure outside the space and there is a pressure difference of a predetermined magnitude or more.

5. The electronic device according to claim 1, wherein the window portion is recessed such that, when the pressure inside the space is less than the pressure outside the space, the amount of displacement toward the space increases as it approaches the center of the window portion in the in-plane direction of the lid.

6. The electronic device according to any one of claims 1 to 5, wherein the thickness of the window portion is 0.05 to 0.15 mm.

7. The electronic device according to any one of claims 1 to 5, wherein the thickness of the bottom of the container or the portion of the lid excluding the window portion is 0.05 to 1.00 mm.

8. The electronic device according to any one of claims 1 to 5, wherein the thickness of the window portion is 5 to 70% of the thickness of the bottom of the container or the portion of the lid excluding the window portion.

9. The area of ​​the aforementioned window portion is 9 to 225 mm² ２ The electronic device according to any one of claims 1 to 5.

10. The electronic device according to any one of claims 1 to 5, wherein the area of ​​the window portion is 50% or less of the area of ​​the bottom of the container or the lid.

11. The window portion is formed in the lid, The electronic device according to any one of claims 1 to 5, wherein the cover, including the window portion, is made of a single material.

12. The electronic device according to claim 11, wherein the container is made of ceramic and the lid is made of metal.

13. The electronic device according to claim 12, wherein the cover is made of an Fe-Ni alloy or an Fe-Ni-Co alloy.

14. The electronic device according to any one of claims 1 to 5, wherein the electronic device is an electrochemical element.

15. The electronic device according to any one of claims 1 to 5, wherein the window portion is formed in the lid.

16. A cover for an electronic device according to claim 15.

17. A method for testing the airtightness of an electronic device according to any one of claims 1 to 5, A step of measuring the displacement of the window portion, A method for testing the airtightness of an electronic device, comprising the step of evaluating the airtightness of the case of the electronic device based on the amount of displacement of the window portion.

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