Sealed battery

Abstract

The utility model provides a sealed battery, which can be used for checking the air tightness of the sealed battery without checking the sealing of gas in advance when the sealed battery is manufactured. The sealed battery is provided with a plurality of sealing mechanisms for sealing the sealed battery, and an inspection hole for inspecting the airtightness of the internal space, the inspection hole communicating from the outside of the sealed battery with an internal space in which any one of the plurality of sealing mechanisms is in contact with the sealed battery.

Description

Technical Field

[0001] The present disclosure relates to a sealed battery. Background Art

[0002] Patent Document 1 describes a method for testing the airtightness of sealed batteries and related technologies. In the technology described in Patent Document 1, a sealed battery is manufactured by sandwiching a sealing material having a recessed portion between a lid and a container within a sealed container for testing the gas atmosphere. The test gas within the sealed container is then removed, and the airtightness is determined by whether the test gas accumulated in the recessed portion leaks.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-026569

[0004] However, the technology described in Patent Document 1 requires that a test gas be sealed in advance when manufacturing a sealed battery, which takes considerable time in the manufacturing process. Utility Model Content

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a sealed battery capable of inspecting the airtightness of the sealed battery without previously sealing a test gas during manufacture of the sealed battery.

[0006] The sealed battery of the present disclosure includes: a plurality of sealing mechanisms for sealing the sealed battery; and an inspection hole communicating from the outside of the sealed battery to an internal space connected to any one of the plurality of sealing mechanisms, for inspecting the airtightness of the internal space.

[0007] Furthermore, the sealed battery may further include a member for sealing the inspection hole after the inspection.

[0008] According to the present disclosure, it is possible to provide a sealed battery capable of inspecting the airtightness of the sealed battery without previously sealing a test gas during manufacture of the sealed battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a flowchart for explaining an example of a secondary battery manufacturing method including a secondary battery inspection method according to an embodiment.

[0010] Figure 2 It is a schematic cross-sectional view showing an example of a component group in a part of the secondary battery according to the embodiment.

[0011] Figure 3 Yes Figure 1 A schematic cross-sectional view of an example of a secondary battery to be inspected during manufacturing in the secondary battery manufacturing method.

[0012] Figure 4 Yes Figure 1 A schematic cross-sectional view of an example of a secondary battery inspection method.

[0013] Figure 5 Yes Figure 1 A schematic cross-sectional view of another example of a secondary battery inspection method.

[0014] Figure 6 It is a schematic diagram for explaining a secondary battery inspection method of a comparative example. DETAILED DESCRIPTION

[0015] The present invention will be described below by way of its embodiments, but the present invention is not limited to the following embodiments. In addition, not all the configurations described in the embodiments are essential as means for solving the problems.

[0016] use Figures 1 to 5 The sealed battery inspection method and an example of the sealed battery according to this embodiment will be described. The following description assumes that the sealed battery is a secondary battery, but the same is applicable to primary batteries.

[0017] Figure 1 This is a flowchart for explaining an example of a secondary battery manufacturing method (hereinafter referred to as the present manufacturing method) including the secondary battery inspection method according to the present embodiment. Figure 2 It is a schematic cross-sectional view showing an example of a component group in a part of the secondary battery according to the embodiment. Figure 3 1 is a schematic cross-sectional view showing an example of a secondary battery to be inspected during production in the present production method.

[0018] Figure 4 and Figure 5 Each of them is a schematic cross-sectional view showing one example and another example of the inspection step in the present manufacturing method.

[0019] In this manufacturing method, first, the components of the secondary battery of this embodiment (hereinafter referred to as the present battery) are stacked (step S1). Among the components constituting the present battery, the secondary battery components may include Figure 2 Component group 10a is illustrated in FIG.

[0020] The component group 10a includes a polarity terminal 11 of one of the negative electrode and the positive electrode in the secondary battery. The polarity terminal 11 is as shown in FIG. Figure 2As shown, it can be composed of a bottom portion and a lead-out portion extending therefrom, and the shape of the lead-out portion can be, for example, cylindrical. Component assembly 10a further includes a sealing material 12, a cover 13, a gasket 14, sealing materials 15 and 16, and an external terminal 17. Sealing materials 12, 15, 16, gasket 14, and external terminal 17 can have, for example, an annular shape. The outer periphery of gasket 14 can have a thick portion that covers the periphery of external terminal 17. Furthermore, the present battery can employ the same structure for the other electrode (not shown), but can also have a shape different from that of the aforementioned one electrode.

[0021] The sealing material 12 is disposed between the cover 13 and the bottom surface of the polarity terminal 11 to seal the cover 13 and the polarity terminal 11 . Hereinafter, the sealing mechanism including the sealing material 12 is referred to as a first sealing mechanism.

[0022] The cover 13 is a cover for the container body that houses the electrode body in the battery. Figure 2 The electrode assembly and the container are not shown in the figure. The external terminal 17 is electrically connected to the polarity terminal 11 and is used to connect the battery to an external load.

[0023] The sealing material 15 is disposed between the lower surface of the gasket 14 and the upper surface of the cover 13 and is a component that seals the gasket 14 and the cover 13. The sealing material 16 is disposed between the upper surface of the gasket 14 and the lower surface of the external terminal 17 and is a component that seals the gasket 14 and the external terminal 17. The sealing material 15, the gasket 14, and the sealing material 16 are components that seal the cover 13 and the external terminal 17. The sealing mechanism formed by these components will be referred to as the second sealing mechanism below. In this way, the present battery has a first and a second sealing mechanism that seals the components that constitute the present battery. In other words, the present battery has a dual mechanism that seals the interior of the secondary battery.

[0024] In step S1, press Figure 2 The order shown is as Figure 3 That is, in step S1, the component assembly 10a is stacked so that the bottom surface of the polarity terminal 11 and the external terminal 17 sandwich the cover 13 and the gasket 14 stacked thereon. Furthermore, the first and second sealing mechanisms described above are provided during stacking.

[0025] Then, in order to achieve the sealing of the first and second sealing mechanisms, in this manufacturing method, the component group 10a stacked in step S1 is fixed by riveting (step S2), and the lead-out portion of the polarity terminal 11 is welded to the external terminal 17 by laser welding or the like (step S3). Figure 3 The secondary battery 10b is shown.

[0026] The caulking process of step S2 can be performed, for example, by pressing the upper surface of the polarity terminal 11 with a member having a protrusion (not shown). By this pressing, a concave portion 11k having a shape corresponding to the protrusion is formed on the upper surface of the polarity terminal 11. Figure 3 In the figure, the polarity terminal 11 after riveting is shown as polarity terminal 11b. In addition, the position of welding in step S3 can be set to Figure 3 The position shown in the middle welded portion 18. By the above-mentioned caulking process and welding process, the airtightness of the portion other than the inspection holes 14h and 17h described later can be improved.

[0027] After riveting and welding component assembly 10a, secondary battery 10b forms an internal space 19 surrounded by polarity terminal 11, sealing material 12, cover 13, gasket 14, sealing materials 15 and 16, and external terminal 17. Internal space 19 is the space formed between the first and second sealing mechanisms connecting the other components. In other words, internal space 19 is a space that is in contact with both the first and second sealing mechanisms.

[0028] The secondary battery 10b is the inspection object. However, in this embodiment, in order to inspect the airtightness of the internal space 19, an inspection hole 14h and an inspection hole 17h are formed on the gasket 14 and the external terminal 17, respectively. The inspection hole 14h and the inspection hole 17h are formed at positions that are connected to each other. The method for forming the inspection holes 14h and 17h is not limited. The inspection holes 14h and 17h are examples of inspection holes used to inspect the airtightness of the internal space 19, and are connected from the outside of the secondary battery 10b that is the inspection object to the internal space 19 connected to either the first or second sealing mechanism. The inspection holes 14h and 17h can also be called connecting holes.

[0029] Thus, in this manufacturing method, the secondary battery 10b is manufactured so as to include the first and second sealing mechanisms for sealing the battery and the inspection holes 14h and 17h.

[0030] After step S3, the sealed area is inspected for leaks (step S4). The sealed area refers to internal space 19. In step S4, gas is supplied from inspection hole 17h or from outside of secondary battery 20b to inspect the airtightness of internal space 19. In either case, the inspection gas flow path is formed by inspection holes 14h, 17h, and internal space 19. In the following example, the inspection gas is helium, but other gases may also be used.

[0031] like Figure 4 As shown, the inspection in step S4 is performed by housing the secondary battery 10b to be inspected, which has been manufactured as described above, in a container 20A. The container 20A has a gas supply port 22A for supplying helium to the inspection hole 17h and a detection port 23A.

[0032] The gas supply port 22A is not connected to the internal space 21A formed by the inner wall of the container 20A and the outside of the secondary battery 10b, but is formed to supply helium only from the inspection hole 17h. Helium is supplied to the internal space 19 from such a gas supply port 22A, and the internal space 19 is filled with helium. The detection port 23A is connected to the internal space 21A, and by pre-decompressing the outside of the container 20A, when helium leaks from at least one of the first and second sealing mechanisms, the helium is caused to flow to the outside of the container 20A. A sensor (not shown) for detecting helium is provided on the inner wall of the detection port 23A or the outside of the container 20A. In addition, the decompression is a decompression that can perform such detection in a short time and is not necessary for the inspection. The above-mentioned sensor can be a sensor that measures the amount of helium leaked to the outside. For example, when the leakage exceeds a specified amount, it can be detected as a helium leak. In addition, although in Figure 4 Although not shown in the figure, in order to prevent the sensor from directly detecting the helium supplied from the gas supply port 22A, a space is provided between the gas supply port 22A and the detection port 23A.

[0033] Alternatively, the check in step S4 can also be performed as follows Figure 5 The secondary battery 10b is housed in a container 20B as shown in FIG. The container 20B has a gas supply port 22B for supplying helium to an internal space 21B formed by the inner wall of the container 20B and the outer side of the secondary battery 10b, and a detection port 23B.

[0034] The gas supply port 22B is connected to the internal space 21B, but a detection port 23B is formed to prevent helium from flowing in through the inspection hole 17h. Helium is supplied to the internal space 21B from the gas supply port 22B, and the internal space 21B is filled with helium. The detection port 23B is not connected to the internal space 21B, and the outside of the container 20B is depressurized in advance. When helium flows into the internal space 19 from at least one of the first and second sealing mechanisms, the helium is caused to flow to the outside of the container 20B from the inspection holes 14h and 17h. The inner wall of the detection port 23B or the outside of the container 20B is in contact with the inner wall of the detection port 23B or the outside of the container 20B. Figure 4 The same as described above, it is equipped with a sensor for detecting helium. Figure 5 Although not shown in the figure, in order to prevent the sensor from directly detecting the helium supplied from the gas supply port 22B, a space is provided between the gas supply port 22B and the detection port 23B.

[0035] according to Figure 4 and Figure 5 Any of the inspection methods shown, for example, as indicated by bold arrows in the drawings, can detect the leakage of helium when there is an error in any of the sealing mechanisms and helium passes therethrough, thereby reliably detecting defective products.

[0036] Finally, the manufacturing process is completed by sealing the inspection holes (step S5). The sealing in step S5 can be performed by, for example, pressing a member slightly larger than the inspection holes 14h and 17h, welding as needed, or inserting an airtight resin and curing it, etc., as long as the sealing method can be used.

[0037] In other words, this battery only needs to have a component that seals the inspection hole after inspection. In other words, this battery for commercial distribution can be a battery in which the inspection holes 14h and 17h of the secondary battery 10b being inspected are sealed with a component (not shown). Thus, in step S1, the battery is stacked and assembled without this component, and then sealed with this component after inspection. Alternatively, this component may simply seal the inspection hole 14h of the gasket 14 or the inspection hole 17h of the external terminal 17.

[0038] The battery manufactured in this way has high airtightness because it has a double sealing mechanism. In fact, in recent years, there have been higher requirements for the service life of batteries and their use in more severe environments, and this battery is manufactured to meet these requirements. For example, when an elastomer such as rubber is used as a sealing member used in a sealing mechanism, in order to ensure the sealing of the battery, the cross-sectional area and length of the sealing member affect the sealing performance. In order to double the sealing performance without changing the material, the sealing length needs to be doubled. However, there are dimensional constraints on the battery cell in the thickness direction, and it is difficult to ensure the sealing length, especially in batteries with small capacity. In contrast, in this battery, since the sealing mechanism is doubled as described above, it is guaranteed to be manufactured to meet the performance requirements mentioned above.

[0039] Furthermore, the secondary battery inspection method of this embodiment enables the airtightness inspection of secondary batteries during manufacturing, without the need for pre-sealing of test gas. Furthermore, airtightness inspection is essential for verifying the integrity of the sealing mechanism. In particular, this inspection ensures reliable and easy inspection even when there are two seals, as in the illustrated sealing mechanism.

[0040] Of course, even if the secondary battery 10b has three or more sealing mechanisms, the sealing status of all of the sealing mechanisms can be reliably and easily inspected. The inspection hole can be any hole that communicates from the outside of the secondary battery with the internal space that is connected to any of the multiple sealing mechanisms and is used to inspect the airtightness of the internal space.

[0041] Regarding the effect of the above-mentioned secondary battery inspection method, Figure 6 The comparison of the comparative examples shown will be described. Figure 6Schematic diagram for explaining a secondary battery inspection method of a comparative example. In the secondary battery inspection method of the comparative example, the inspection method for a secondary battery having only a single sealing mechanism is directly applied to a secondary battery having a dual sealing mechanism.

[0042] Comparative example secondary battery 50 includes a gasket 54 without inspection hole 14h, replacing gasket 14 in secondary battery 10b, and an external terminal 57 without inspection hole 17h, replacing external terminal 17 in secondary battery 10b. Furthermore, comparative example container 60 is sealed with circumferential contacts 64u on the upper surface of lid 13 of secondary battery 50 to form an internal space 61u, and with circumferential contacts 64d on the lower surface of lid 13 to form an internal space 61d. Container 60 also includes a gas supply port 62 for supplying helium to fill internal space 61u or both internal spaces 61u and 61d, and a detection port 63 equipped with a sensor for detecting helium.

[0043] However, in the comparative example, Figure 6 As indicated by the bold arrow, a normal inspection result is obtained when the first sealing mechanism formed by gasket 54 and sealing materials 15 and 16 is defective and allows helium to pass through, while the second sealing mechanism formed by sealing material 12 is sound and prevents helium from passing through. Conversely, in the comparative example, a normal inspection result is also obtained when the first sealing mechanism is sound and the second sealing mechanism is defective. In other words, in the comparative example secondary battery 50, a normal inspection result is obtained in all these cases, resulting in the outflow of defective products.

[0044] In order to verify the effect of this manufacturing method on such a comparative example, a cover assembly was made by integrating the positive terminal, the negative terminal, the sealing material and the cover. Then, a secondary battery having inspection holes 14h and 17h like this battery and a secondary battery not having inspection holes 14h and 17h like the secondary battery 50 involved in the comparative example were made. Here, as the sealing materials 12, 15, and 16 used in the first and second sealing mechanisms, a flat ring made of vinylidene fluoride fluororubber with an outer diameter of φ7, an inner diameter of φ4, and a thickness of 1mm was used. In addition, the volume of the internal space 19 was adjusted to 12mm 3 In addition, for verification purposes, cracks were placed on the flat ring of the first sealing mechanism to simulate a faulty product.

[0045] exist Figure 4 In the inspection method shown, after degassing under reduced pressure, helium is filled into the internal space 19 from the inspection hole 17h at 0.1 MPa. Figure 5 In the inspection method shown, after the cover assembly is degassed under reduced pressure, the internal space 21B is filled with helium and the pressure is reduced to 0.1 MPa through the inspection hole 17h. The pressure reduction is performed using a vacuum pump set to 0.001 MPa.

[0046] As a result, in Figure 4 In the inspection method shown, the internal space 19 is filled with helium, and the inspection result at the inspection port 23A is a failure (NG). Figure 5 In the inspection method shown, if the pressure in internal space 19 is reduced through inspection holes 14h and 17h, helium leaks, resulting in a poor (NG) test result at inspection port 23B. On the other hand, in the comparative example, internal space 19 is filled with helium, but even if the pressure in internal space 19 is reduced through inspection port 63, helium does not leak into internal space 61d, resulting in a good (OK) test result at inspection port 63.

[0047] As mentioned above, it was confirmed that Figure 4 and Figure 5 In any of the inspection methods, the soundness of each of the first and second sealing mechanisms can be reliably and easily inspected, thereby preventing the outflow of defective products as in the comparative example.

[0048] In addition, the present invention is not limited to the above-mentioned embodiment and can be appropriately changed within the scope of the main purpose. For example, in the above-mentioned embodiment, only one example is given for the shape of each component constituting the sealed battery, but any shape that can realize the function of each component can be used, and the material of each component can also be used as long as it can realize the function of the component. In addition, the component group described in the above-mentioned embodiment is only an example of a component group that constitutes multiple sealing structures in a sealed battery. Some of these components can be formed in an integrated manner, or some of these components can be formed using multiple components.

Claims

1. A sealed battery, characterized in that: have: A plurality of sealing mechanisms for sealing the sealed battery; and An inspection hole communicates from the outside of the sealed battery to an internal space where any one of the plurality of sealing mechanisms is connected, and is used to inspect the airtightness of the internal space.

2. The sealed battery according to claim 1, wherein A member for sealing the inspection hole after the inspection is performed is provided.

Images