Electronic device manufacturing method and leak inspection device

Abstract

Provided is an electronic device manufacturing method with which the airtightness of a case can be easily evaluated. The electronic device manufacturing method is a method for manufacturing an electronic device having a sealed case, and comprises: a sealing step (step S1) of sealing the case under a reduced-pressure environment; a measurement step (steps S2, S4) of measuring a displacement amount of a predetermined measurement surface of the sealed case; and an evaluation step (steps S3, S5) of evaluating airtightness of the case on the basis of the measured displacement amount.

Description

Manufacturing method of electronic device and leak inspection device

[0001] The present invention relates to a manufacturing method and a leak detection apparatus for an electronic device.

[0002] Various electronic devices have been disclosed in the past, such as electrochemical elements in which a power generating element and the like are housed in an internal space formed by a recessed container and a lid covering the opening of the recessed container. For example, Japanese Patent Application Laid-Open No. 2010-56067 discloses a coin-type lithium secondary battery that includes a battery element as a power generating element, a metal case, a metal sealing plate, and a gasket that insulates the metal case from the metal sealing plate.

[0003] Some contents of electronic devices react with moisture in the air and their characteristics deteriorate. Therefore, the container (case) of the electronic device may be required to be highly airtight. International Publication No. 2014 / 7215 discloses an all-solid-state secondary battery including a battery body composed of a solid electrolyte, a positive electrode, and a negative electrode. This all-solid-state secondary battery is characterized in that it includes a resin part including at least two or more resin layers surrounding the battery body, and at least one of the resin layers in the resin part has a lower water absorption rate than the other resin layers.

[0004] Although not related to electronic devices, Japanese Patent Application Laid-Open No. 2014-85246 discloses an internal pressure inspection device and an internal pressure inspection method for a sealed container in which a body and a lid are connected by a joint, and the device and method determine whether the internal pressure is good or bad by measuring the deformation of the lid due to the internal pressure of the sealed container using a laser displacement sensor.

[0005] JP 2010-56067 A International Publication No. 2014 / 7215 JP 2014-85246 A

[0006] One possible method for testing the airtightness of an electronic device case is the immersion method (bombing method) specified in JIS Z 2331 (helium leak test method). In this test method, the electronic device is first placed in a chamber, which is evacuated, and then filled with helium to create a pressurized helium atmosphere. If the airtightness of the electronic device case is insufficient, helium will enter the case. The electronic device is then moved to another chamber, which is then evacuated, and the airtightness of the case can be determined based on whether helium is detected.

[0007] While this inspection method using a helium detector can evaluate the airtightness of a case with high accuracy, it takes a long time to perform the work and is therefore not suitable for, for example, full inspection of products before shipping.

[0008] An object of the present invention is to provide a method for manufacturing an electronic device that can easily evaluate the airtightness of a case. Another object of the present invention is to provide a leak testing device that can easily evaluate the airtightness of a case.

[0009] A method for manufacturing an electronic device according to one embodiment of the present invention is a method for manufacturing an electronic device having a sealed case, and includes a sealing step of sealing the case in a reduced pressure environment, a measurement step of measuring the amount of displacement of a predetermined measurement surface of the sealed case, and an evaluation step of evaluating the airtightness of the case based on the measured amount of displacement.

[0010] A leak testing device according to one embodiment of the present invention is a leak testing device for evaluating the airtightness of a case of an electronic device having a sealed case, and includes a measuring device that measures the amount of displacement of a predetermined measurement surface of the electronic device, and a control device that controls the measuring device, wherein the control device receives the amount of displacement measured from the measuring device and evaluates the airtightness of the case based on the measured amount of displacement.

[0011] According to the present invention, the airtightness of a case can be easily evaluated.

[0012] FIG. 1 is a flow diagram of a method for manufacturing an electronic device according to one embodiment of the present invention. FIG. 2 is a perspective view schematically showing the configuration of a battery as an example of an electronic device. FIG. 3 is an exploded perspective view of the battery of FIG. 2. FIG. 4 is a diagram for explaining an overview of a method for evaluating airtightness in this embodiment. FIG. 5 is a flow diagram of a method for manufacturing an electronic device according to another embodiment of the present invention. FIG. 6 is a diagram schematically showing the functional configuration of a leak inspection device according to one embodiment of the present invention. FIG. 7 is a scatter plot showing the relationship between the difference in recess volume immediately after sealing and the recess volume 7 days after sealing, and the amount of He leakage. FIG. 8 is a scatter plot showing the relationship between the recess volume 7 days after sealing and the amount of He leakage.

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated. The dimensional ratios between the components shown in each drawing do not necessarily represent the actual dimensional ratios.

[0014] [Electronic Device Manufacturing Method] Figure 1 is a flow diagram of an electronic device manufacturing method according to one embodiment of the present invention. This manufacturing method is a method for manufacturing an electronic device having a sealed case. This manufacturing method includes a sealing step (step S1) of sealing the case under a reduced pressure environment, a post-sealing measurement step (step S2) of measuring the amount of displacement of a predetermined measurement surface of the sealed case, a post-sealing evaluation step (step S3) of evaluating the airtightness of the case based on the amount of displacement measured in the post-sealing measurement step, a post-exposure measurement step (step S4) of measuring the amount of displacement of the measurement surface measured in the post-sealing measurement step after a predetermined time has elapsed since the post-sealing measurement step, and a post-exposure evaluation step (step S5) of evaluating the airtightness of the case based on the amount of displacement measured in the post-sealing measurement step and the amount of displacement measured in the post-exposure measurement step. The post-sealing evaluation step (step S3) is performed between the post-sealing measurement step (step S2) and the post-exposure measurement step (step S4), and the post-exposure evaluation step (step S5) is performed after the post-exposure measurement step (step S4).

[0015] [Electronic Device] The electronic device produced by the present invention is an electronic device having a sealed case. Examples of the electronic device include discrete devices, semiconductors, sensors, integrated circuits, resistors, condensers, coils, batteries, and capacitors. The electronic device is preferably an electrochemical element such as a lithium ion battery, a lithium ion capacitor, or an electric double layer capacitor.

[0016] The following describes an example of manufacturing the battery 1 shown in Figures 2 and 3. Figure 2 is a perspective view schematically showing the configuration of the battery 1, which is an example of an electronic device, and Figure 3 is an exploded perspective view of the battery 1. The battery 1 includes a case 10 and a power-generating element 20. The case 10 has a container 11 and a lid 12. The container 11 has a recess 111 (Figure 3) for disposing the power-generating element 20 therein, and the lid 12 is configured to cover the opening of the recess 111.

[0017] The container 11 is made of a material such as ceramics. The container 11 may be made of any material that can ensure a predetermined airtightness, such as metal, resin, or glass. If the container 11 is made of a conductive material such as metal, an insulator or the like may be disposed between the container 11 and the power generating element 20.

[0018] The material of the lid member 12 is, for example, metal. Like the container 11, the lid member 12 may be made of any material that can ensure a predetermined airtightness, and may be made of ceramics, resin, glass, or the like. It is preferable that the lid member 12 be elastically deformable. Therefore, the material of the lid member 12 is preferably metal or resin, and particularly preferably metal.

[0019] 3, the power generating element 20 is a laminate including 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, the battery 1 is a so-called all-solid-state battery. There are no particular limitations on the types of the positive electrode layer 21, the negative electrode layer 22, and the solid electrolyte layer 23, and any known material can be used as each of the materials.

[0020] 2 and other drawings, the battery 1 may also include terminals for extracting current, lead members for connecting the terminals to the power-generating element 20, and fixing members (spacers) for fixing the power-generating element 20. The battery 1 may employ any known configuration for these members.

[0021] [Sealing Step] First, the power generating element 20 is housed in the case 10, and the case 10 is sealed in a reduced pressure environment (sealing step (step S1)). Specifically, the power generating element 20 is placed in the recess 111 of the container 11, and then the opening of the recess 111 is covered with the lid member 12 to secure the container 11 and the lid member 12 together. The container 11 and the lid member 12 are secured together so that the case 10 is hermetically sealed. In the example shown in FIG. 2 etc., the container 11 and the lid member 12 are secured together by seam welding a metal seal ring 112 ( FIG. 3 ) formed around the recess 111 ( FIG. 3 ) to the lid member 12.

[0022] In this embodiment, the sealing step (step S1) is performed in a reduced pressure environment, i.e., an evacuated environment. Sealing in a reduced pressure environment can be performed, for example, by a seam welding device equipped with a vacuum chamber. The degree of vacuum during sealing is not particularly limited, but may be, for example, 10 －１ Pa or less, preferably 10 －２ Pa or less.

[0023] The airtightness of the case 10 is evaluated through steps S2 to S5 below. Before describing each step in detail, an overview of this evaluation method will be given with reference to FIG.

[0024] Since the case 10 is sealed in a reduced pressure environment, the pressure inside the case 10 is lower than atmospheric pressure immediately after sealing. Therefore, when the case 10 is returned to an atmospheric pressure environment, the lid member 12 is pressed by the atmosphere and deformed, becoming concave toward the inside (see the "standard" column in FIG. 4, the "good product" column (He leak amount is 10 －１０ P.A.M. ３ / s). If the airtightness of the case 10 is very poor, for example, if there is a large defective joint at the joint between the container 11 and the lid 12, the air will flow into the inside of the case 10 from this place, and the pressure difference between the inside and outside of the case 10 will disappear. Therefore, the lid 12 will not have a concave shape, or the size of the concave will be smaller than that of a good product (see the "Standard" column in Figure 4, "Large Leakage Amount" (He leak amount is 10 －３ P.A.M. ３ See the line (approximately / s).

[0025] Even if there is a defective joint at the joint between the container 11 and the lid material 12, if the size of the defective joint is small and the amount of air inflow is small, the pressure difference between the inside and outside of the case 10 is maintained for a while after sealing, so the size of the dent in the lid material 12 will be about the same as that of a good product (see the "standard" column in Figure 4, "small leakage amount" (He leakage amount is 10 －９ P.A.M. ３ / s) and "medium leakage amount" (He leakage amount is 10 －５ P.A.M. ３ / s). Even in this case, if there is an air inflow, the pressure difference will gradually decrease over time, and the size of the depression will gradually decrease. In this case, the greater the amount of air inflow, the greater the amount of change in the size of the depression (the rate at which the size of the depression decreases) (see the "After 7 days" column, "Small leak" and "Medium leak" rows in Figure 4). However, if the amount of air inflow becomes greater than a certain level, the pressure difference will disappear at an early stage, and the amount of change in the size of the depression will again become smaller (see the "After 7 days" column, "Large leak" row in Figure 4).

[0026] In this way, by evaluating the size of the dent in the lid material 12 and the amount of change in the size of the dent after a predetermined time has passed, it is possible to evaluate the airtightness of the case 10. Each of steps S2 to S5 will be described in detail below.

[0027] [Post-sealing measurement step] The displacement of a predetermined measurement surface of the sealed case is measured (step S2). For example, in the case of the battery 1 shown in Fig. 2, the surface of the lid material 12 of the case 10 is used as the measurement surface, and the size of the depression in the lid material 12 can be used as the displacement.

[0028] The "amount of displacement" is a value (index) representing the magnitude of deformation of the measurement surface. In the post-sealing evaluation process (step S3) described below, this "amount of displacement" is compared with a predetermined threshold value to evaluate the airtightness of the case. The "amount of displacement" may be any amount that is correlated with the magnitude of deformation of the case, as long as it is the same amount as that used to determine the threshold value. For example, the "amount of displacement" may be the amount of deformation from the reference surface at the center of the in-plane direction of the measurement surface when there is no recess (the depth of the recess at the center position). Alternatively, the "amount of displacement" may be the amount of greatest deformation from the reference surface (the maximum depth of the recess).

[0029] The "amount of displacement" may also be the volume of the recessed portion of the measurement surface. Specifically, the measurement surface without a recess can be used as the reference surface, and the volume of the area enclosed by the reference surface and the measurement surface after recession can be used as the "amount of displacement." By using the volume of the recessed portion of the measurement surface as the "amount of displacement," information over a wide range of the measurement surface is reflected in the "amount of displacement," thereby reducing the variation in measurement results. The volume of the recessed portion of the measurement surface can be determined, for example, by measuring the three-dimensional shape of the measurement surface using an optical displacement meter. The reference surface may be, for example, a plane passing through the four corners of the measurement surface or a plane passing through the periphery, or the reference surface may be determined using the least squares method. The reference surface may also be a surface measured in a vacuum state (before opening to the atmosphere) after vacuum sealing.

[0030] The post-sealing measurement step (step S2) may be performed some time after the sealing step (step S1) (for example, after another inspection step), but it is preferable to perform it as soon as possible after the sealing step (step S1).

[0031] [Post-sealing evaluation step] The airtightness of the case is evaluated based on the displacement amount (hereinafter referred to as the "first displacement amount") measured in the post-sealing measurement step (step S2) (post-sealing evaluation step (step S3)). For example, the first displacement amount is compared with a predetermined threshold value, and if the first displacement amount is less than the threshold value, the airtightness of the case is evaluated as poor.

[0032] For example, the threshold value can be determined based on a relationship between the first displacement amount and the airtightness of the case of a plurality of electronic devices (the same electronic devices as the electronic device to be manufactured) that has been previously investigated. Specifically, the first displacement amount is measured for the plurality of electronic devices by the same measurement as in the post-sealing measurement process, and the airtightness of these electronic devices is evaluated by an immersion method (bombing method) or the like, thereby obtaining the relationship between the first displacement amount and the airtightness of the case. Based on this relationship, the first displacement amount at which the leakage amount is equal to or greater than a predetermined amount can be determined as the threshold value.

[0033] An electronic device whose case is evaluated as having poor airtightness in the post-sealing evaluation step (step S3) may be determined to be a defective product at this point and excluded from the subsequent steps (steps S4 and S5). Alternatively, the post-sealing evaluation step (step S3) may not determine whether the electronic device is a good product or a defective product, and the determination may be made in the post-exposure evaluation step (step S5) described below. If the post-exposure evaluation step (step S5) determines whether the electronic device is a good product or a defective product, the post-sealing evaluation step (step S3) may be omitted.

[0034] [Measurement step after leaving] After a predetermined time has elapsed since the measurement step after sealing (step S2), the displacement amount of the same measurement surface as that measured in the measurement step after sealing is measured (measurement step after leaving (step S4)). That is, after a predetermined time has elapsed since the measurement step after sealing (step S2), the same measurement as in the measurement step after sealing (step S2) is performed again. The surface to be measured is the same surface as the measurement surface measured in the measurement step after sealing, and the same "displacement amount" as that measured in the measurement step after sealing (the depth of the recess at the center position, the maximum depth of the recess, or the volume of the recessed portion of the measurement surface, etc.) is measured.

[0035] The longer the time between the post-sealing measurement step and the post-leaving measurement step (hereinafter referred to as the "measurement interval"), the more accurately the airtightness of the case can be evaluated. On the other hand, if the measurement interval is too long, the lead time increases and productivity decreases. The lower limit of the measurement interval depends on the dimensions of the case, the allowable amount of leakage, etc., but is preferably one day, more preferably three days, and even more preferably five days. The upper limit of the measurement interval is, for example, one month, preferably two weeks.

[0036] [Post-storage evaluation process] The airtightness of the case is evaluated based on the displacement amount (first displacement amount) measured in the post-sealing measurement process (step S2) and the displacement amount (hereinafter referred to as the "second displacement amount") measured in the post-storage measurement process (step S4) (post-storage evaluation process (step S5)).

[0037] As explained in Figure 4, even if there is a poor joint, if the amount of air inflow is small, the pressure difference between the inside and outside of the case will be maintained for a while after sealing, so the displacement of the measurement surface will be about the same as that of a good product. By performing the post-exposure measurement step (step S5) a predetermined time after the post-sealing measurement step (step S2), it is possible to detect minute leaks that were difficult to detect in the post-sealing measurement step.

[0038] In the post-exposure evaluation step (step S5), it is preferable to evaluate the airtightness of the case based on the difference between the first displacement amount and the second displacement amount. It is also possible to evaluate the airtightness of the case based solely on the absolute value of the second displacement amount. However, the absolute values ​​of the first displacement amount and the second displacement amount may contain errors, such as dimensional tolerances of the container 11 and the lid material 12, or the inclination of the lid material 12 when welding the container 11 and the lid material 12. Because this error is common to both the first displacement amount and the second displacement amount, it can be canceled out by taking the difference between the first displacement amount and the second displacement amount. Therefore, the airtightness of the case can be evaluated more accurately by using the difference between the first displacement amount and the second displacement amount, rather than by evaluating solely on the absolute value of the second displacement amount.

[0039] A possible method for evaluating the airtightness of the case based on the difference between the first displacement amount and the second displacement amount is, for example, to compare the difference between the first displacement amount and the second displacement amount with a predetermined threshold, and evaluate the case as having poor airtightness if the difference is equal to or greater than the threshold. As in the case of the post-sealing evaluation step (step S3), this threshold can be determined based on a relationship between the difference and the airtightness of the case, which is investigated in advance for multiple electronic devices (the same electronic devices as the electronic device to be manufactured).

[0040] As described with reference to FIG. 4 , the difference between the first displacement amount and the second displacement amount (the rate at which the size of the recess decreases) typically increases as the amount of air inflow (leakage amount) increases, but decreases again once the amount of air inflow exceeds a certain level. Therefore, the airtightness of the case may not be determined solely based on the difference between the first displacement amount and the second displacement amount. Therefore, the airtightness of the case may be evaluated by taking into account at least one of the absolute value of the first displacement amount and the absolute value of the second displacement amount in addition to the difference between the first displacement amount and the second displacement amount. By taking into account at least one of the absolute value of the first displacement amount and the absolute value of the second displacement amount, it is possible to detect defective products with a large amount of air inflow ("large leakage amount" in FIG. 4 ) that cannot be detected by evaluation based on the difference.

[0041] That is, in the post-exposure evaluation process (step S5), only products whose difference between the first displacement amount and the second displacement amount is less than a predetermined threshold and whose absolute value of the first displacement amount and / or the absolute value of the second displacement amount is greater than the predetermined threshold may be determined to be good products.

[0042] In addition, if products determined to be defective in the post-sealing evaluation process (step S3) have been excluded from subsequent evaluation, i.e., if products whose absolute value of the first displacement amount is less than a predetermined threshold have already been excluded, the second evaluation process (step S5) may evaluate the airtightness of the case based only on the difference between the first displacement amount and the second displacement amount.

[0043] [Advantages of this embodiment] The method for manufacturing an electronic device according to one embodiment of the present invention has been described above. According to this embodiment, the airtightness of a case can be easily evaluated.

[0044] As described above, it is preferable to measure the displacement of a predetermined measurement surface of the case by performing a post-sealing measurement step (step S2) and a post-leaving measurement step (step S4) and determining the difference between the first displacement amount and the second displacement amount. The airtightness of the case can be evaluated more accurately by evaluating the difference between the first displacement amount and the second displacement amount. However, as shown in FIG. 5, for example, it is also possible to perform the displacement measurement only once (measurement step (step S2)). ＊ )), and evaluate the airtightness of the case based on the absolute value of the measured displacement (evaluation step (step S3 ＊ )) is also possible. When the displacement is measured only once, it is preferable to measure it one day or more after sealing the case, more preferably three days or more, and even more preferably five days or more. The upper limit of the time between sealing the case and measurement is preferably one month, more preferably two weeks.

[0045] Although the above description has been given of the case where battery 1 ( FIG. 2 ), which is an all-solid-state battery, is manufactured as an example of an electronic device, the electronic device to be manufactured is not limited to an all-solid-state battery. The electronic device to be manufactured may be any electronic device having a sealed case. The electronic device is preferably an electrochemical element having a power-generating element. The above-described method for manufacturing an electronic device is suitable when the electronic device to be manufactured is an all-solid-state battery having a solid electrolyte, and is particularly suitable when the electronic device has a sulfide-based solid electrolyte.

[0046] In the above description, the case 10 is composed of a container 11 and a lid 12, and the lid 12 is used as the measurement surface. However, the configuration of the case of the electronic device is not limited to this. In the above-described method for manufacturing an electronic device, the case is sealed, and at least a portion of the case has a part that elastically deforms in response to the pressure difference between the inside and outside of the case. For example, a portion of the case may be made thinner than other portions, and this portion may be used as the measurement surface. It is preferable that the measurement surface be flat.

[0047] In other words, the method for manufacturing an electronic device is a method for manufacturing an electronic device having a sealed case, and it only needs to include a sealing step of sealing the case in a reduced pressure environment, a measurement step of measuring the amount of displacement of a predetermined measurement surface of the sealed case, and an evaluation step of evaluating the airtightness of the case based on the measured amount of displacement.

[0048] 6 is a diagram schematically illustrating the functional configuration of a leak inspection device 5 according to one embodiment of the present invention. The leak inspection device 5 is a leak inspection device that evaluates the airtightness of the case of an electronic device that has a sealed case, and includes a measuring device 51, a work transfer device 52, and a control device 53.

[0049] The measuring device 51 is a device that measures the amount of displacement of a predetermined measurement surface of the case of the electronic device, and is, for example, an optical displacement meter.

[0050] The workpiece transfer device 52 is a device that moves the electronic device to be measured to a position suitable for measurement by the measuring device 51. The workpiece transfer device 52 is, for example, a robot arm.

[0051] The control device 53 includes an arithmetic device 531 and a storage device 532. The arithmetic device 531 executes a program stored in the storage device 532. The control device 53 controls the measuring device 51 and the workpiece transfer device 52 in accordance with this program. The control device 53 also receives measurement results from the measuring device 51 and evaluates the airtightness of the case of the electronic device 1 based on the measurement results.

[0052] Next, the operation of the leak testing device 5 will be described. First, a tray 61 containing a large number (e.g., several hundred) of electronic devices 1 to be tested is placed near the work transfer device 52. The tray 61 may be placed manually or mechanically. The work transfer device 52 picks up the electronic devices 1 placed on the tray 61 one by one and moves them to a position suitable for measurement by the measuring device 51. The measuring device 51 measures the amount of displacement of a predetermined measurement surface of the case of the electronic device 1 and transmits the measurement results to the control device 53. The control device 53 receives the amount of displacement of the measurement surface from the measuring device 51 and evaluates the airtightness of the case of the electronic device 1 based on the amount of displacement. After the measurement by the measuring device 51 is completed, the work transfer device 52 returns the electronic device 1 to its original position on the tray 61. These operations are repeated for all electronic devices 1 placed on the tray 61.

[0053] The measurement of the displacement amount by the measuring device 51 is similar to that described in the post-encapsulation measuring step (step S2) and the post-exposure measuring step (step S4) in the method of manufacturing the electronic device shown in FIG.

[0054] The evaluation of airtightness by the control device 53 is similar to that described in the post-sealing evaluation step (step S3) and the post-exposure evaluation step (step S5) in the electronic device manufacturing method of Fig. 1. The control device 53, for example, compares the amount of displacement measured by the measuring device 51 with a threshold value that has been determined in advance and stored in the storage device 532, and evaluates the airtightness of the case as poor if the measured amount of displacement is less than the threshold value.

[0055] The leak test device 5 may further include a sorting mechanism that sorts the electronic devices 1 according to the evaluation results by the control device 53. For example, if the airtightness of the case of the electronic device 1 is evaluated as poor, the work transfer device 52 may move the electronic device 1 to a separately provided NG discharge tray 62 instead of returning it to the tray 61. In this example, the work transfer device 52 also functions as the sorting mechanism, but the sorting mechanism may be a device separate from the work transfer device 52.

[0056] The control device 53 may store an identifier for identifying the electronic device 1 and the displacement amount measured by the measuring device 51 in association with each other in the storage device 532. This allows steps S2 to S5 of the method for manufacturing the electronic device shown in FIG. 1 to be performed semi-automatically, as will be described next.

[0057] First, the electronic device 1 after the sealing step (step S1) is placed in a tray 61 and placed near the work transfer device 52, and an inspection is performed using the leak inspection device 5. The control device 53 associates the identifier of the measured electronic device 1 with the displacement amount measured by the measuring device 51 and stores the association information in the storage device 532. After a predetermined time has elapsed, the tray 61 is placed near the work transfer device 52 again, and an inspection is performed using the leak inspection device 5. The control device 53 can obtain the displacement amount measured previously from the storage device 532 based on the identifier of the electronic device 1. Therefore, the control device 53 can evaluate the airtightness of the case based on the displacement amount (corresponding to the first displacement amount) that is the result of the previous measurement and the displacement amount (corresponding to the second displacement amount) that is the result of the current measurement.

[0058] The leak test device 5 according to one embodiment of the present invention has been described above. According to this embodiment, the airtightness of a case can be easily evaluated.

[0059] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0060] Several sealed all-solid-state batteries were manufactured, and the relationship between the size of the recess in the case (lid) and airtightness was investigated. This all-solid-state battery included a case and a power-generating element. The case consisted of a ceramic recessed container and a metal (Kovar) lid covering the opening of the recessed container, and was sealed (seam-welded) under a reduced pressure environment. The outer dimensions of the case were 10.5 mm x 10.5 mm x 4.0 mm, and the thickness of the lid was 100 μm.

[0061] The size of the depression in the lid material was measured immediately after sealing and 7 days after sealing. Specifically, the three-dimensional shape of the lid material was measured by area designation using a white light interference 3D displacement meter "WI-5000" manufactured by Keyence Corporation, and the volume of the depression (hereinafter referred to as "depression volume") was measured. The "depression volume" was calculated by summing the height information of the measurement points (each 40 μm × 40 μm) for approximately 49,000 points, and the plane obtained by the least squares method from the height data within the designated area was used as the reference plane.

[0062] The He leakage amount of this all-solid-state battery was measured by the immersion method (bombing method) specified in JIS Z 2331 (helium leakage test method). Figure 7 shows the relationship between the difference (hereinafter referred to as "ΔV") between the recess volume immediately after sealing and the recess volume 7 days after sealing and the He leakage amount. Figure 8 shows the relationship between the recess volume 7 days after sealing and the He leakage amount.

[0063] From FIG. 7, it can be seen that ΔV is, for example, 0.05 mm ３ The following all-solid-state batteries have a He leakage rate of 10 －１０ P.A.M. ３ / s, and the He leak amount is 10 －５ P.A.M. ３ 8, it can be seen that the He leakage amount is 10 －１０ P.A.M. ３ / s, the recess volume after 7 days from sealing was 0.30 mm ３ Therefore, for example, when ΔV is 0.05 mm or more, ３ and the recess volume after 7 days is 0.30 mm or less. ３ The all-solid-state battery having the above value can be determined as a non-defective product. ３ )) and Figure 8 (dent volume after 7 days (mm ３ By using both methods, it is possible to accurately distinguish between non-defective products.

[0064] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention.

Claims

1. A method for manufacturing an electronic device having a sealed case, comprising: a sealing step of sealing the case in a reduced pressure environment; a measurement step of measuring the amount of displacement of a predetermined measurement surface of the sealed case; and an evaluation step of evaluating the airtightness of the case based on the measured amount of displacement.

2. The method for manufacturing an electronic device according to claim 1, wherein the measurement process includes a post-sealing measurement process and a post-leaving measurement process for measuring the amount of displacement of the measurement surface measured in the post-sealing measurement process a predetermined time after the post-sealing measurement process.

3. The method for manufacturing an electronic device as described in claim 2, wherein the evaluation process includes a post-exposure evaluation process carried out after the post-exposure measurement process, and in the post-exposure evaluation process, the airtightness of the case is evaluated based on the amount of displacement measured in the post-sealing measurement process and the amount of displacement measured in the post-exposure measurement process.

4. The method for manufacturing an electronic device as described in claim 3, wherein in the post-exposure evaluation process, the airtightness of the case is evaluated based on the difference between the amount of displacement measured in the post-sealing measurement process and the amount of displacement measured in the post-exposure measurement process.

5. The method for manufacturing an electronic device described in claim 4, wherein in the post-exposure evaluation process, in addition to the difference between the amount of displacement measured in the post-sealing measurement process and the amount of displacement measured in the post-exposure measurement process, the airtightness of the case is evaluated based on at least one of the absolute value of the amount of displacement measured in the post-sealing measurement process and the absolute value of the amount of displacement measured in the post-exposure measurement process.

6. The method for manufacturing an electronic device described in claim 3, wherein the evaluation process further includes a post-sealing evaluation process that is performed after the post-sealing measurement process and before the post-leaving evaluation process, and in the post-sealing evaluation process, the airtightness of the case is evaluated based on the amount of displacement measured in the post-sealing measurement process.

7. The method for manufacturing an electronic device according to claim 1, wherein the measuring step is carried out one day or more after the sealing step, and the evaluation step evaluates the airtightness of the case based on the absolute value of the displacement measured in the measuring step.

8. The method for manufacturing an electronic device according to any one of claims 1 to 7, wherein the amount of displacement is the volume of a recessed portion of the measurement surface.

9. The method for manufacturing an electronic device according to any one of claims 1 to 7, wherein the measurement surface is a metal.

10. The method for producing an electronic device according to any one of claims 1 to 7, wherein the electronic device is an electrochemical element equipped with a power generating element.

11. The method for producing an electronic device according to any one of claims 1 to 7, wherein the electronic device is an all-solid-state battery.

12. A leak testing apparatus for evaluating the airtightness of an electronic device having a sealed case, comprising: a measuring device for measuring an amount of displacement of a specified measurement surface of the electronic device; and a control device for controlling the measuring device, wherein the control device receives the amount of displacement measured from the measuring device and evaluates the airtightness of the case based on the measured amount of displacement.

13. The leak inspection apparatus according to claim 12, further comprising a workpiece transfer device that moves the electronic device to a position suitable for measurement by the measuring apparatus.

14. The leak test apparatus according to claim 12, further comprising a sorting mechanism that sorts the electronic devices according to the evaluation result by the control device.

15. A leak testing device as described in any one of claims 12 to 14, wherein the control device has a storage device that stores an identifier for identifying the electronic device and an amount of displacement measured by the measuring device in association with each other, and the control device obtains past measurement results from the storage device using the identifier of the electronic device, and evaluates the airtightness of the case based on the amount of displacement that is the past measurement result and the amount of displacement that is the current measurement result.

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