Inspection Device and Manufacturing Method for Thin Film Batteries

Abstract

The present invention provides an inspection device for a thin-film battery that can detect defective sealing portions of a heat-sealed portion. According to the present invention, there can be provided an inspection device (200) for a thin-film battery (100) including an electrode body and a film outer package body that houses the electrode body therein and has a heat-sealed portion at a peripheral edge. The inspection device (200) includes: a temperature measurement device (210) that measures the temperature distribution of the heat-sealed portion; and a first determination unit (241) that controls the temperature measurement device within a predetermined time after the heat-sealed portion is formed in the film outer package body, and determines the presence or absence of a defective sealing portion based on the measured temperature distribution.

Description

Technical Field

[0001] The present invention relates to an inspection device and a manufacturing method for thin-film batteries. Background Art

[0002] Conventionally, there has been known a thin-film battery in which an electrode body and an electrolytic solution are housed inside a thin-film exterior member (hereinafter referred to as a film exterior body), and the periphery is heat-sealed to be hermetically sealed. In such a thin-film battery, there is a concern that the electrolytic solution may leak if there is a portion with poor airtightness. Therefore, the airtightness is generally inspected before shipment. For example, Patent Document 1 describes that the airtightness is inspected by placing the thin-film battery in a sealed container and comparing the undulating shape of the surface of the thin-film battery before and after reducing the pressure inside the closed container.

[0003] Patent Document 1: International Publication No. 2011 / 158878

[0004] According to the research of the present inventors, during heat sealing, if there is insufficient heating caused by poor heating or biting of foreign matter, etc., sometimes the sealing width becomes locally narrow, etc., and local defects (sealing defective portions) occur in the heat-sealed portion. In such a thin-film battery, the sealing defective portion is likely to crack, and there may be a situation where the withstand voltage strength is insufficient during use. In the technique of Patent Document 1, although the airtightness can be inspected, the sealing defective portion of the heat-sealed portion cannot be detected. Therefore, there is a concern that the withstand voltage strengths of thin-film batteries are inconsistent. Summary of the Invention

[0005] The present invention has been completed in view of the above circumstances, and an object thereof is to provide an inspection device for a thin-film battery capable of detecting a sealing defective portion of a heat-sealed portion, and a manufacturing method for a thin-film battery having a stable withstand voltage strength.

[0006] According to the present invention, there is provided an inspection device for a thin-film battery including an electrode body and a film exterior body that houses the electrode body inside and has a heat-sealed portion at the periphery. The inspection device includes: a temperature measurement device that measures the temperature distribution of the heat-sealed portion; and a first determination unit that controls the temperature measurement device within a predetermined time after the heat-sealed portion is formed in the film exterior body, and determines the presence or absence of a sealing defective portion based on the measured temperature distribution.

[0007] According to the above inspection device, it is possible to highly accurately detect the location of the sealing defective portion, that is, the presence or absence of local defects such as a locally narrowed sealing width. Thereby, it is possible to provide a thin-film battery having a stable withstand voltage strength.

[0008] In a preferred embodiment of the inspection device disclosed herein, it further includes: a thickness measuring device that measures the thickness distribution of the heat-sealed portion; and a second determination unit that, after the heat-sealed portion is formed in the film outer package, controls the thickness measuring device and determines the presence or absence of a sealing defect portion based on the measured thickness distribution. According to the above structure, the sealing defect portion of the heat-sealed portion can be confirmed three-dimensionally, and the sealing defect portion of the heat-sealed portion can be detected with higher accuracy.

[0009] In a preferred embodiment of the inspection device disclosed herein, the thin-film battery includes: a terminal having one end electrically connected to the electrode body inside the film outer package and the other end extending and protruding outside the film outer package; and a sealing adhesive film provided on the surface of the terminal facing the film outer package and fused to the film outer package. The heat-sealed portion includes: a first sealing portion formed by heat-sealing the film outer package and the sealing adhesive film; and a second sealing portion formed by heat-sealing the film outer packages to each other. The first determination unit is configured to determine the first sealing portion and the second sealing portion according to different determination criteria. In the first sealing portion and the second sealing portion, for example, the heating set temperature of the heat seal and the temperature change over time (cooling method) after heat sealing can be different. For example, when the terminal is made of metal, the first sealing portion can be a portion that cools more easily than the second sealing portion. By making the determination criteria for the first sealing portion and the second sealing portion different from each other, the sealing defect portion can be detected with high accuracy.

[0010] In a preferred embodiment of the inspection device disclosed herein, the first determination unit is configured to at least measure the temperature distribution of the first sealing portion. In the first sealing portion, since a sealing adhesive film is sandwiched between the terminal and the film outer package, sealing defects may sometimes occur more easily than in the second sealing portion. However, according to the above structure, the sealing defect portion in the first sealing portion can be detected with high accuracy.

[0011] In a preferred embodiment of the inspection device disclosed herein, the first determination unit is configured to obtain the temperature distribution after the first time and the temperature distribution after the second time, which is longer than the first time, within the specified time, calculate the temperature change per unit time, and determine the presence or absence of the sealing defect portion based on the temperature change amount. By performing the quality determination based on the temperature change amount (ΔT) over time, the sealing defect portion can be detected with high accuracy.

[0012] In addition, according to the present invention, there is provided a method for manufacturing a thin-film battery, including a step of inspecting the heat-sealed portion using any of the inspection devices disclosed herein after the heat-sealed portion is formed.

[0013] According to the above manufacturing method, a thin-film battery with excellent airtightness, durability, and stable pressure resistance can be manufactured. Description of the Drawings

[0014] Figure 1 It schematically shows a partial cross-sectional top view of a thin-film battery according to an embodiment.

[0015] Figure 2 It is a schematic diagram showing the structure of an inspection device according to an embodiment.

[0016] Figure 3 It is a flowchart showing a manufacturing method according to an embodiment.

[0017] Description of the Reference Numerals:

[0018] 10... film outer package; 16... heat seal part; 17... first seal part; 18... second seal part; 20... electrode body; 40... sealant film; 100... thin-film battery; 200... inspection device; 210... temperature measurement device; 220... thickness measurement device; 230... display device; 240... control device; 241... first determination part; 242... second determination part; 243... notification part. Detailed Embodiments

[0019] Hereinafter, preferred embodiments of the technology disclosed herein will be described with appropriate reference to the drawings. Among them, matters required for implementation other than those specifically mentioned in this specification (such as the inspection device and manufacturing method of the thin-film battery) (such as the general structure and construction process of the thin-film battery) can be grasped as design matters of those skilled in the art based on the prior art. The technology disclosed herein can be implemented based on the content disclosed in this specification and the common general knowledge in the art. In addition, in the following drawings, components and parts that perform the same function are labeled with the same reference numerals, and repeated descriptions may sometimes be omitted or simplified.

[0020] In this specification, the "thin-film battery" refers to the entire battery having a structure in which an electrode body is housed inside a film (sheet)-shaped outer package member. In addition, in this specification, the "battery" is a term referring to the entire power storage device capable of extracting electric energy, and is a concept including primary batteries and secondary batteries. In addition, in this specification, the "secondary battery" is a term referring to the entire power storage device capable of repeated charging and discharging, and is a concept including so-called storage batteries (chemical batteries) such as lithium-ion secondary batteries and nickel-metal hydride batteries and capacitors (physical batteries) such as electric double layer capacitors.

[0021] <Thin-Film Battery 100>

[0022] First, the thin-film battery 100 to be inspected will be described. Figure 1is a schematic partial cross-sectional top view showing a thin-film battery 100. The thin-film battery 100 includes an outer package 10, an electrode body 20, a positive terminal 32, a negative terminal 34, and an electrolytic solution (not shown). Here, the thin-film battery 100 is a lithium-ion secondary battery. The positive terminal 32 and the negative terminal 34 are examples of terminals. In addition, in the following description, it is assumed that the reference numerals X, Y, and Z in the drawings represent the short-side direction, the long-side direction orthogonal to the short-side direction, and the thickness direction of the thin-film battery 100, respectively. The long-side direction is an example of the direction in which the positive terminal 32 and the negative terminal 34 extend and protrude. However, these are merely directions for convenience of explanation and do not limit the configuration of the thin-film battery 100 in any way.

[0023] The outer package 10 is a container for housing the electrode body 20 and the electrolytic solution. Here, in order to enable heat sealing, at least the inner surface (the surface facing the electrode body 20) of the outer package 10 is formed of a resin layer. The resin layer is formed of a thermoplastic resin such as a polyolefin resin or a polyester resin, for example. As the polyolefin resin, for example, polyethylene (PE), polypropylene (PP), acid-modified polyolefin resins such as maleic anhydride-modified polypropylene, and maleic anhydride polyester can be cited. Here, the outer package 10 is a so-called laminated film. The laminated film can be of the same structure as that used in a conventionally known laminated battery, for example, and is not particularly limited. The outer package 10 is configured to include a first resin layer, a metal layer, and a second resin layer laminated in that order from the side closer to the electrode body 20.

[0024] Here, the outer package 10 is formed into a bag shape by overlapping two rectangular films and sealing the periphery. As Figure 1 shown by the double-dashed line, a heat-sealed portion 16 is formed at the periphery of the outer package 10 (here, the four sides surrounding the electrode body 20). The electrode body 20 and the electrolytic solution are hermetically sealed inside the outer package 10 by the heat-sealed portion 16.

[0025] Here, the heat-sealed portion 16 is formed in a ring shape along the outer edge of the outer package 10. The heat-sealed portion 16 is composed of a first sealed portion 17 and a second sealed portion 18. The first sealed portion 17 is a portion where the outer package 10 and a sealing adhesive film 40 described later are heat-sealed. Here, the first sealed portion 17 is formed in a strip shape at both end portions in the long-side direction Y of the outer package 10. Specifically, the first sealed portion 17 is formed at the edge portion on the side where the positive terminal 32 extends and protrudes (the right side in the long-side direction Y) of the outer package 10 and at the edge portion on the side where the negative terminal 34 extends and protrudes (the left side in the long-side direction Y) of the outer package 10, respectively. However, when the positive terminal 32 and the negative terminal 34 extend and protrude from one end portion in the long-side direction Y together, the first sealed portion 17 may be formed only at one end portion in the long-side direction Y. The first sealed portion 17 is formed with a predetermined sealing width (the vertical length from the inner edge to the outer edge).

[0026] The second sealing portion 18 is the portion of the heat-sealing portion 16 other than the first sealing portion 17. The second sealing portion 18 is the portion where the opposed film exterior bodies 10 are heat-sealed to each other. Here, the second sealing portion 18 is formed in a strip shape at least at both end portions in the short-side direction X of the film exterior body 10. However, for example, when using a folded film or a cylindrical film, etc., the second sealing portion 18 may not be formed at one or both end portions in the short-side direction X. The second sealing portion 18 is formed with a specified sealing width (the vertical length from the inner edge to the outer edge). The sealing width of the second sealing portion 18 may be the same as or different from that of the first sealing portion 17.

[0027] The structure of the electrode body 20 may be the same as that of a conventionally well-known battery and is not particularly limited. The electrode body 20 includes a sheet-like positive electrode (positive electrode sheet) and a sheet-like negative electrode (negative electrode sheet). As Figure 1 shown here, the electrode body 20 is a laminated electrode body in which a square (typically rectangular) positive electrode sheet and a square (typically rectangular) negative electrode sheet are laminated in an insulating state. However, the electrode body 20 may also be a wound electrode body in which a strip-shaped positive electrode sheet and a strip-shaped negative electrode sheet are laminated in an insulating state and wound along the length direction. Typically, the positive electrode has a positive electrode current collector and a positive electrode active material layer (not shown) fixed on the positive electrode current collector and containing a positive electrode active material. Typically, the negative electrode has a negative electrode current collector and a negative electrode active material layer (not shown) fixed on the negative electrode current collector and containing a negative electrode active material.

[0028] As Figure 1 shown, the electrode body 20 has a portion (positive electrode current collector exposed portion) 22 where the positive electrode active material layer is not formed at one end portion in the long-side direction Y ( Figure 1 the right end portion). The positive electrode current collector exposed portion 22 is joined to the positive electrode terminal 32. The electrode body 20 has a portion (negative electrode current collector exposed portion) 24 where the negative electrode active material layer is not formed at the other end portion in the long-side direction Y ( Figure 1 the left end portion). Here, in the long-side direction Y, the negative electrode current collector exposed portion 24 is disposed on the opposite side of the positive electrode current collector exposed portion 22. The negative electrode current collector exposed portion 24 is joined to the negative electrode terminal 34.

[0029] The electrolyte may be the same as that of a conventionally well-known battery and is not particularly limited. The electrolyte is, for example, a non-aqueous electrolyte containing a non-aqueous solvent and a salt complex. The non-aqueous solvent includes, for example, carbonates. The salt complex is, for example, a fluorine-containing lithium salt such as lithium hexafluorophosphate (LiPF6). However, the electrolyte may be integrated with the electrode body 20 in a solid state (solid electrolyte).

[0030] The positive electrode terminal 32 is a plate-shaped metal component. The positive electrode terminal 32 is disposed at one end portion in the long-side direction Y (Figure 1 the right end portion). One end of the positive terminal 32 is electrically connected to the positive current collector exposed portion 22 inside the film outer package 10. The other end of the positive terminal 32 extends and protrudes to the outside of the film outer package 10.

[0031] As Figure 1 shown, a sealing adhesive film 40 is integrated with a part of the surface of the positive terminal 32 on the side facing the film outer package 10. Typically, the sealing adhesive film 40 is fused to the surface of the positive terminal 32 on the side facing the film outer package 10. However, the sealing adhesive film 40 can also be pasted on the positive terminal 32 using an adhesive or the like. The sealing adhesive film 40 is provided along the edge of the side of the film outer package 10 where the positive terminal 32 extends and protrudes ( Figure 1 the right side). The sealing adhesive film 40 extends along the short side direction X. One end of the sealing adhesive film 40 ( Figure 1 the right end portion) protrudes from the film outer package 10.

[0032] The sealing adhesive film 40 covers the positive terminal 32 in such a manner that the positive current collector exposed portion 22 does not directly contact the film outer package 10. The sealing adhesive film 40 is fused (e.g., heat-fused) to the opposing film outer package 10. Thus, as Figure 1 shown, at the edge of the side of the film outer package 10 where the positive terminal 32 extends and protrudes (the right side in the long side direction Y), the sealing adhesive film 40 is sandwiched between the positive terminal 32 and the film outer package 10, and a heat-sealed portion 16 is formed.

[0033] Typically, the sealing adhesive film 40 is made of a resin material. The sealing adhesive film 40 can be made of a resin material that is resistant to the electrolyte used and melts at a temperature similar to that of the resin layer (e.g., the first resin layer) of the film outer package 10. The sealing adhesive film 40 can exhibit appropriate adhesiveness to both the film outer package 10 and the positive terminal 32. As the resin material constituting the sealing adhesive film 40, for example, a thermoplastic resin exemplified as the material for the resin layer constituting the film outer package 10 can be cited. The sealing adhesive film 40 can also be a polyolefin film.

[0034] The negative terminal 34 is a plate-shaped metal component. The negative terminal 34 is disposed at the other end of the long side direction Y ( Figure 1 the left end portion). In the long side direction Y, the negative terminal 34 is disposed on the opposite side of the positive terminal 32. However, the positive terminal 32 and the negative terminal 34 can also extend and protrude from the same-direction end of the film outer package 10, for example, one end of the long side direction Y. One end of the negative terminal 34 is electrically connected to the negative current collector exposed portion 24 inside the film outer package 10. The negative terminal 34 extends along the long side direction Y. The other end of the negative terminal 34 extends and protrudes to the outside of the film outer package 10.

[0035] AsFigure 1 As shown, similar to the positive terminal 32, a sealing film 40 is integrally formed on a part of the surface of the negative terminal 34 on the side facing the outer film package 10. The sealing film 40 is fused (e.g., heat-fused) to the opposing outer film package 10. Thus, as Figure 1 shown, on the edge portion of the outer film package 10 on the side where the negative terminal 34 extends and protrudes (the left side in the longitudinal direction Y), the sealing film 40 is sandwiched between the negative terminal 34 and the outer film package 10, and a heat-sealed portion 16 is formed.

[0036] <Inspection Device 200>

[0037] Next, an inspection device 200 for the thin-film battery 100 will be described. Figure 2 FIG. is a schematic diagram showing the structure of the inspection device 200. The inspection device 200 is a device for detecting defective sealing portions (local defects) in a specified detection range of the heat-sealed portion 16 of the thin-film battery 100 after heat-sealing. Figure 2 The inspection device 200 shown in FIG. includes a temperature measurement device 210, a thickness measurement device 220, a display device 230, and a control device 240. However, in other embodiments, the thickness measurement device 220 and / or the display device 230 can also be omitted. Hereinafter, each component will be described.

[0038] The temperature measurement device 210 is a device for measuring the temperature distribution of the heat-sealed portion 16. Here, the temperature measurement device 210 is disposed above the thin-film battery 100. The temperature measurement device 210 is, for example, a thermal imaging camera that visualizes the distribution of the surface temperature of the thin-film battery 100. Here, the temperature measurement device 210 photographs the thin-film battery 100 from above and measures the temperature distribution of all parts of the heat-sealed portion 16. However, the photographing range of the heat-sealed portion 16 can also be only the first sealing portion 17 or the second sealing portion 18. Preferably, the temperature measurement device 210 is configured to be able to measure at least the temperature of the first sealing portion 17. The temperature measurement device 210 is electrically connected to the control device 240 and is controlled by the control device 240. The temperature distribution (typically image data, such as a thermogram photographed by a thermal imaging camera) measured by the temperature measurement device 210 is input to the control device 240.

[0039] The thickness measurement device 220 is a device that measures the thickness distribution of the heat-sealed portion 16. The thickness measurement device 220 is, for example, a non-contact sensor. Here, the thickness measurement device 220 is an optical length measurement sensor having a light-emitting unit 221 and a light-receiving unit 222 that are opposed to each other in the thickness direction Z. A gap is provided between the light-emitting unit 221 and the light-receiving unit 222 so as to accommodate at least a part of the heat-sealed portion 16 of the thin-film battery 100. In the thickness measurement device 220, light is irradiated from the light-emitting unit 221 to the light-receiving unit 222. The light-emitting unit 221 is electrically connected to the control device 240 and is controlled by the control device 240. The value of the received light amount is input from the light-receiving unit 222 to the control device 240 and converted into thickness.

[0040] The display device 230 is a device that displays information related to the thin-film battery 100 and the heat-sealed portion 16. The display device 230 is, for example, a liquid crystal display or an organic EL display. The display device 230 can be configured to display whether the thin-film battery 100 is a good product or a defective product. The display device 230 can be configured to display, for example, the temperature distribution measured by the temperature measurement device 210 (for example, a thermal image captured by a thermal imaging camera) together with a temperature chart showing the correspondence between color and temperature. The display device 230 can be configured to display the thickness distribution measured by the thickness measurement device 220.

[0041] The control device 240 includes a first determination unit 241, a second determination unit 242, and a notification unit 243. Among them, in other embodiments, the second determination unit 242 and / or the notification unit 243 can also be omitted. The first determination unit 241 is a control unit that determines the presence or absence of a sealing defective portion based on the temperature distribution of the heat-sealed portion 16. The second determination unit 242 is a control unit that determines the presence or absence of a sealing defective portion based on the thickness distribution of the heat-sealed portion 16.

[0042] The notification unit 243 is a control unit that displays whether the thin-film battery 100 is a good product or a defective product on the display device 230 based on the determination results of the first determination unit 241 and / or the second determination unit 242. Specifically, in the case where there is no sealing defective portion, the notification unit 243 displays that the thin-film battery 100 is a good product, and in the case where there is a sealing defective portion, the notification unit 243 displays that the thin-film battery 100 is a defective product. The notification unit 243 can be configured to display the determination results of the first determination unit 241 and / or the second determination unit 242, the obtained temperature distribution, and / or the thickness distribution on the display device 230 without change.

[0043] The control device 240 includes, for example: a central processing unit (CPU), which executes commands of a control program; a ROM (read only memory), which stores the program executed by the CPU; a RAM (random access memory), which is used as a working area for expanding the program; and a recording device such as a memory, which stores the above program and various data. Each part of the control device 240 can be constituted by software or by hardware. The control device 240 is configured to be communicably connected to the temperature measuring device 210, the thickness measuring device 220, and the display device 230 respectively to control them.

[0044] <Manufacturing Method of Thin Film Battery 100>

[0045] Next, the manufacturing method of the thin film battery 100 will be described. Figure 3 It is a flowchart showing an example of the manufacturing method. Figure 3 The manufacturing method includes a sealing process (step S10) and an inspection process (step S20). The inspection process (step S20) is an example of an inspection method of the thin film battery 100 using the inspection device 200. The inspection process (step S20) includes a temperature measurement process (step S21), a first determination process (step S22), a thickness measurement process (step S24), a second determination process (step S25), and a display process (steps S23, S26, S27). However, in other embodiments, some of them (for example, steps S24 and S25) can be omitted. In addition, the thickness measurement process and the second determination process can be performed before the temperature measurement process and the first determination process. And other processes can be included at any stage.

[0046] First, in step S10, a heat seal portion 16 (a first seal portion 17 and a second seal portion 18) is formed on the film outer package 10. For example, an electrode body 20 impregnated with an electrolyte is sandwiched between a pair of laminated films, and the periphery of the laminated film is heat-sealed. For example, heat sealing can be performed by using a heating rod heated to a specified processing temperature to heat-seal the resin layer. The processing temperature can be different between the first seal portion 17 and the second seal portion 18. Through heat sealing, the electrode body 20 is housed inside the film outer package 10, and the film outer package 10 is sealed by the heat seal portion 16. Then, it proceeds to step S20.

[0047] Among them, the operations from the sealing process (step S10) to the inspection process (step S20) can be performed manually or by automatic control of the control device 240. In this case, for example, as long as a conveying mechanism such as a conventionally known conveying arm or a conveying belt is used, such as Figure 2It is sufficient to convey the thin-film battery 100 to the vicinity of the inspection device 200 as indicated by the arrow in the figure.

[0048] Next, in step S20, the inspection device 200 is used to inspect the heat-sealed portion 16 of the thin-film battery 100 to be inspected. Specifically, first, in the temperature measurement process (step S21), the first determination unit 241 obtains the temperature distribution of the heat-sealed portion 16. For example, when this process is executed by the automatic control of the control device 240, the first determination unit 241 controls the conveyance mechanism to move the thin-film battery 100 directly below the temperature measurement device 210. After the heat-sealed portion 16 is formed in step S10, the first determination unit 241 controls the temperature measurement device 210 within a prescribed time to obtain the temperature distribution of the heat-sealed portion 16 (specifically, the first sealing portion 17 and / or the second sealing portion 18). The prescribed time is the time during which the heat-sealed portion 16 is maintained in a warm state. Here, the first determination unit 241 drives the temperature measurement device 210 once within the prescribed time and obtains the temperature distribution of the heat-sealed portion 16 after the first time has elapsed.

[0049] Here, the temperature distribution is data indicating the relationship between the position in plan view and the measured temperature over the entire circumference of the annularly formed heat-sealed portion 16. However, it may also be data indicating the relationship between the position in plan view and the measured temperature only for the strip-shaped first sealing portion 17, or may be data indicating the relationship between the position in plan view and the measured temperature only for the second sealing portion 18. The temperature distribution can be, for example, a group of groups each composed of three values: the coordinate in the short-side direction X, the coordinate in the long-side direction Y, and the measured temperature, for each imaging portion obtained by dividing the imaging range at equal intervals in the short-side direction X and the long-side direction Y. Then, the process proceeds to step S22.

[0050] Next, in the first determination process (step S22), the first determination unit 241 determines the presence or absence of a sealing defect portion based on the temperature distribution obtained in step S21. The determination of the presence or absence of a sealing defect portion can be performed, for example, by comparing the measured temperature of each imaging portion with a temperature threshold value preset as a determination reference. For example, the temperature threshold value is set based on the heating set temperature of the heating rod used in heat sealing, the elapsed time since step S10, the physical properties of the film outer package 10 and / or the sealing adhesive film 40 (for example, the melting temperature of the resin layer), etc., and is stored in the first determination unit 241. Typically, the temperature threshold values are different between the first sealing portion 17 and the second sealing portion 18. For example, the temperature threshold value of the first sealing portion 17 can be set based on the melting temperature of the film outer package 10 and the sealing adhesive film 40, the material of the positive terminal 32 and / or the negative terminal 34, etc. For example, the temperature threshold value of the second sealing portion 18 can be set based on the melting temperature between the film outer packages 10.

[0051] If insufficient heating such as heating failure or foreign matter biting occurs in the heat-sealing part 16, the temperature of the heat-sealing part 16 locally decreases. When the measured temperatures of all the imaging parts are equal to or higher than the temperature threshold, the first determination unit 241 determines that there is no defective sealing part (S22: Yes). Here, when all the measured temperatures are equal to or higher than the temperature threshold in the data indicating the relationship between the positions around the entire circumference of the heat-sealing part 16 and the measured temperatures, the first determination unit 241 determines that there is no defective sealing part (S22: Yes). Note that, for example, when only the temperature distribution of the first sealing part 17 or the second sealing part 18 is obtained in the temperature measurement process (step S21), etc., the first determination unit 241 may also determine that there is no defective sealing part when all the measured temperatures are equal to or higher than the temperature threshold in the data indicating the relationship between the positions of the first sealing part 17 or the second sealing part 18 and the measured temperatures. Then, the process proceeds to step S24.

[0052] On the other hand, when the measured temperature of at least one imaging part is lower than the temperature threshold, the first determination unit 241 determines that there is a defective sealing part (S22: No). Here, when the measured temperature is lower than the temperature threshold even at one position in the data indicating the relationship between the positions around the entire circumference of the heat-sealing part 16 and the measured temperatures, the first determination unit 241 also determines that there is a defective sealing part (S22: No). Note that, for example, when only the temperature distribution of the first sealing part 17 or the second sealing part 18 is obtained in the temperature measurement process (step S21), etc., the first determination unit 241 may also determine that there is a defective sealing part when the measured temperature is lower than the temperature threshold even at one position in the data indicating the relationship between the positions of the first sealing part 17 or the second sealing part 18 and the measured temperatures. Then, the process proceeds to step S23. In the display process (step S23), the notification unit 243 displays on the display device 230 that the thin-film battery 100 to be inspected is a defective product. Then, the control ends.

[0053] Next, in the thickness measurement process (step S24), the second determination unit 242 obtains the thickness distribution of the heat-sealed portion 16 (specifically, the first sealing portion 17 and / or the second sealing portion 18). For example, when this process is executed by the automatic control of the control device 240, the second determination unit 242 moves the thin-film battery 100 within a specified measurement range, and controls the thickness measurement device 220 to emit light from the light-emitting unit 221 and receive the value of the light reception amount from the light-receiving unit 222. In the second determination unit 242, the thickness distribution is generated based on the light reception amount. The thickness distribution is, for example, data showing the relationship between the position in plan view and the measured thickness over the entire circumference of the annular heat-sealed portion 16. It should be noted that it may also be data showing the relationship between the position in plan view and the measured thickness only for the first sealing portion 17 formed in a strip shape, or it may be data showing the relationship between the position in plan view and the measured thickness only for the second sealing portion 18. The thickness distribution can be configured, for example, as a group in which the coordinates in the short side direction X and / or the long side direction Y of the measurement range are associated with the measured thickness. Then, the process proceeds to step S25.

[0054] Next, in the second determination process (step S25), the second determination unit 242 determines the presence or absence of a sealing defect portion based on the thickness distribution obtained in step S24. For example, the presence or absence of a sealing defect portion can be determined by comparing the measured thickness with a reference thickness range preset as a determination criterion. For example, the reference thickness range is set based on the thickness of the film package 10, the sealing adhesive film 40, the positive terminal 32, and / or the negative terminal 34, and is stored in the second determination unit 242. Typically, the reference thickness range is different between the first sealing portion 17 and the second sealing portion 18.

[0055] For example, if there are wrinkles in the film package 10 or the sealing adhesive film 40 is distorted during heat sealing, the thickness of the heat-sealed portion 16 will be locally thinned or thickened. When the measured thickness is within the reference thickness range, the second determination unit 242 determines that there is no sealing defect portion (S25: Yes). For example, when the measured thickness is within the reference thickness range in the data showing the relationship between the position over the entire circumference of the heat-sealed portion 16 and the measured thickness, the second determination unit 242 determines that there is no sealing defect portion (S25: Yes). It should be noted that, for example, when the thickness distribution of only the first sealing portion 17 or the second sealing portion 18 is obtained in the thickness measurement process (step S24), etc., when the measured thickness is within the reference thickness range in the data showing the relationship between the position of the first sealing portion 17 or the second sealing portion 18 and the measured thickness, the second determination unit 242 determines that there is no sealing defect portion (S25: Yes). Then, the process proceeds to step S26. In the display process (step S26), the notification unit 243 displays on the display device 230 that the thin-film battery 100 to be inspected is a non-defective product. Then the control ends.

[0056] On the other hand, when the measured thickness at at least one part is outside the reference thickness range, the second determination unit 242 determines that there is a defective sealing part (S25: No). For example, when, in the data showing the relationship between the position around the entire circumference of the heat-sealing part 16 and the measured thickness, the measured thickness is outside the reference thickness range at even one part, the second determination unit 242 also determines that there is a defective sealing part (S25: No). It should be noted that, for example, when only the thickness distribution of the first sealing part 17 or the second sealing part 18 is obtained in the thickness measurement process (step S24), etc., when the measured thickness is outside the reference thickness range at even one part in the data showing the relationship between the position of the first sealing part 17 or the second sealing part 18 and the measured thickness, the second determination unit 242 also determines that there is a defective sealing part (S25: No). Then, it proceeds to step S27. In the display process (step S27), the notification unit 243 displays on the display device 230 that the thin-film battery 100 to be inspected is a defective product. Then the control ends.

[0057] As described above, according to the inspection device 200, it is possible to detect with high precision the presence or absence of defective sealing parts of the heat-sealing part 16. In addition, according to the above manufacturing method, it is possible to manufacture a thin-film battery 100 with stable withstand voltage strength.

[0058] As described above, specific examples of the present invention have been described in detail, but these are merely examples and do not limit the technical solution. The technology described in the technical solution includes technologies obtained by various deformations and changes to the above-described specific examples.

[0059] In the above-described embodiment, the first determination unit 241 is configured to drive the temperature measurement device 210 once within a specified time and obtain the temperature distribution after the first time. However, it is not limited thereto. The first determination unit 241 may also drive the temperature measurement device 210 two or more times within a specified time and photograph the transient change of the temperature multiple times. The first determination unit 241 may obtain the temperature distribution after the first time and the temperature distribution after a second time longer than the first time within a specified time. In this case, for each photographing unit, the first determination unit 241 may obtain the difference in time based on the comparison between the temperature distribution after the second time and the temperature distribution after the first time, thereby calculating the temperature change amount (ΔT) per unit time and generating the distribution of the temperature change amount. In the first determination unit 241, the determination of the presence or absence of defective sealing parts may be performed by comparing the temperature change amount with a temperature change amount threshold preset as a determination reference for each photographing unit.

Claims

1. An inspection device for a thin-film battery, which is provided with an electrode body and a film outer package that houses the electrode body therein and has a heat-sealed portion at its periphery. The inspection device is characterized by comprising: a temperature measurement device that measures the temperature distribution of the heat-sealed portion; and a first determination unit that, after the heat-sealed portion is formed in the film outer package, controls the temperature measurement device within a specified time and determines the presence or absence of a sealing defect portion based on the measured temperature distribution. The first determination unit is configured to obtain the temperature distribution after a first time and the temperature distribution after a second time that is longer than the first time within the specified time, calculate the temperature change amount per unit time, and determine the presence or absence of the sealing defect portion based on the temperature change amount.

2. The inspection device according to claim 1, wherein It further comprises: a thickness measurement device that measures the thickness distribution of the heat-sealed portion; and a second determination unit that, after the heat-sealed portion is formed in the film outer package, controls the thickness measurement device and determines the presence or absence of a sealing defect portion based on the measured thickness distribution.

3. The inspection device according to claim 1 or 2, characterized in that the thin-film battery comprises: a terminal, one end of which is electrically connected to the electrode body inside the film outer package and the other end of which extends and protrudes to the outside of the film outer package; and a sealing adhesive film provided on the surface of the terminal facing the film outer package and fused to the film outer package. The heat-sealed portion has: a first sealing portion formed by heat-sealing the film outer package and the sealing adhesive film; and a second sealing portion formed by heat-sealing the film outer packages to each other. The first determination unit is configured to determine the first sealing portion and the second sealing portion according to different determination criteria.

4. The inspection device according to claim 3, characterized in that the first determination unit is configured to at least measure the temperature distribution of the first sealing portion.

5. A method for manufacturing a thin-film battery, characterized in that it includes a step of using the inspection device according to any one of claims 1 to 4 to inspect the heat-sealed portion after the heat-sealed portion is formed.

Images