Sealed storage battery and manufacturing method for the same

Abstract

To provide a high-quality sealed storage battery and a manufacturing method for the same that can reduce defects in a welded portion between an injection port and a plug body to improve the sealing properties of a battery case by preventing an electrolyte from adhering to a back side of a case wall having the injection port.SOLUTION: A sealed storage battery 10 includes a battery case 1 and an electrode body 2 accommodated in the battery case. A case wall portion 12 constituting the battery case has an inlet 121 for injecting electrolyte 5 into the battery case and a plug body 122 for sealing the inlet by welding. Between the case wall portion and the electrode body, a shielding film 7 is provided to shield a back surface 12b of the case wall portion from the electrolyte injected from the injection port adhering to the back surface. The shielding film has a nozzle insertion port 7P through which an electrolyte injection nozzle 6 is inserted into a position opposite the injection port.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a sealed storage battery and a manufacturing method thereof. [Background technology]

[0002] For example, Patent Document 1 discloses a lithium ion secondary battery having an insulating film interposed between an electrode body and a case body of a battery case, with an upper end portion located on the case lid side inclined toward the electrode body. An injection port for injecting an electrolyte (non-aqueous electrolyte) is formed in the case lid of this lithium ion secondary battery (sealed storage battery), and after the electrode body is housed in the battery case, an injection nozzle for the electrolyte is inserted into the battery case from the injection port, and the electrolyte is discharged from an outlet formed on the side of the tip of the injection nozzle, thereby injecting a required amount of electrolyte into the battery case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-95836 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the insulating film of Patent Document 1 has an upper end open toward the case lid, there is a possibility that the electrolyte discharged from the discharge port of the injection nozzle may splash and adhere to the back side of the case lid. Usually, after the electrolyte is injected, the injection port is sealed by welding the plug, so if the electrolyte adheres to the back side of the case lid, the electrolyte is vaporized by the welding heat, and the pressure inside the battery case increases. Therefore, there is a problem that the gas inside the battery case penetrates into the molten metal formed at the boundary between the injection port and the plug, causing defects such as pinholes in the welded part, which reduces the sealing property inside the battery case.

[0005] The present disclosed technology has been made in consideration of such problems, and has an objective of providing a high-quality sealed storage battery and a manufacturing method thereof that can prevent electrolyte from adhering to the back side of the case wall having an injection port, reduce defects in the weld between the injection port and the plug, and improve the sealing performance of the battery case. [Means for solving the problem]

[0006] (1) One aspect of the disclosed technology for solving the above problems is a sealed storage battery comprising: a battery case; and an electrode body contained within the battery case; one case wall constituting the battery case has an injection port for injecting an electrolyte into the battery case and a plug body for sealing the injection port by welding; and between the one case wall and the electrode body, a shielding film is provided for preventing the electrolyte injected from the injection port from adhering to a back surface side of the one case wall; and the shielding film has a nozzle insertion port formed in a position opposite the injection port, through which an injection nozzle for the electrolyte is inserted.

[0007] (2) In the sealed storage battery described in (1), it is preferable that an insulating film is provided between the electrode body and another case wall portion constituting the battery case, and the shielding film is extended from one end of the insulating film and connected to the other end.

[0008] (3) In the sealed storage battery described in (1), it is preferable that the one case wall portion is provided with a safety valve formed so as to be able to open in response to an increase in pressure inside the battery case, and the shielding film is provided with a slit groove at a position opposite the safety valve which is broken when the safety valve opens.

[0009] (4) In the sealed storage battery described in any one of (1) to (3), it is preferable that the shielding film is formed of a material having a thermal conductivity lower than the thermal conductivity of the one case wall portion having the injection port.

[0010] (5) Another aspect of the disclosed technique for solving the above problems is a method for manufacturing a sealed storage battery comprising: a battery case; and an electrode body accommodated in the battery case; one case wall constituting the battery case has an injection port for injecting an electrolyte into the battery case and a plug body that seals the injection port by welding; a shielding film is provided between the one case wall and the electrode body, the shielding film being provided with a shielding film that prevents the electrolyte injected from the injection port from adhering to a back surface side of the one case wall; and a nozzle insertion port is formed in the shielding film at a position opposite to the injection port, through which an injection nozzle for the electrolyte is inserted; and after the electrode body is accommodated in the battery case, an electrolyte injection step of injecting the electrolyte into the battery case from the injection nozzle inserted into a gap between the shielding film and the electrode body from the injection port; and a plug welding step of welding the injection port and the plug body after the electrolyte injection step.

[0011] (6) In the manufacturing method of the sealed storage battery described in (5), it is preferable that an insulating film is interposed between the electrode body and another case wall portion constituting the battery case, and the shielding film is extended from one end of the insulating film and connected to the other end.

[0012] (7) In the method for manufacturing a sealed storage battery described in (5), it is preferable that the one case wall portion is provided with a safety valve formed so as to be able to open in response to an increase in pressure inside the battery case, and the shielding film is provided with a slit groove at a position opposite the safety valve, which is broken when the safety valve is opened.

[0013] (8) In the method for manufacturing a sealed storage battery described in any one of (5) to (7), it is preferable that the shielding film is formed of a material having a thermal conductivity lower than the thermal conductivity of the one case wall portion having the injection port. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view of a sealed storage battery according to one aspect of the present embodiment. [Diagram 2]2 is a schematic perspective view showing a state in the middle of winding the positive electrode body and the negative electrode body of the electrode assembly shown in FIG. 1, with a separator sandwiched between them. FIG. [Diagram 3] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 4] 2 is a cross-sectional view of FIG. 1 shown in FIG. [Diagram 5] FIG. 2 is a development view of the shielding film and insulating film shown in FIG. [Figure 6] FIG. 2 is a flowchart showing a method for manufacturing the sealed storage battery shown in FIG. [Figure 7] 7 is a schematic cross-sectional view taken along line CC in FIG. 4, illustrating a state in which an electrolyte is being injected into the battery case in the electrolyte injection step shown in FIG. 6. [Figure 8] 7 is a schematic cross-sectional view taken along the CC cross section shown in FIG. 4, illustrating a state in which the boundary between the injection port and the plug is being welded in the plug welding step shown in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Description of this sealed battery> Next, the configuration of a sealed storage battery according to one aspect of an embodiment of the disclosed technology will be described in detail with reference to the drawings. Fig. 1 shows a schematic cross-sectional view of a sealed storage battery according to one aspect of the present embodiment. Fig. 2 shows a schematic perspective view of a state in the middle of winding in which the positive electrode body and the negative electrode body of the electrode body shown in Fig. 1 are stacked with a separator sandwiched therebetween and wound. Fig. 3 shows an AA cross-sectional view shown in Fig. 1. Fig. 4 shows a BB cross-sectional view shown in Fig. 1. Fig. 5 shows a development view of the shielding film and the insulating film shown in Fig. 1.

[0016] As shown in Figs. 1 to 5, the sealed storage battery 10 includes a battery case 1, an electrode assembly 2, a current collecting terminal 4, and an electrolyte 5. One of the case walls 12 constituting the battery case 1 includes an inlet 121 for injecting the electrolyte 5 into the battery case 1, and a plug 122 for sealing the inlet 121 by welding. Here, the battery case 1 includes a case body 11 in the form of a bottomed rectangular cylinder having a rectangular opening 111, and a long, flat sealing body 12 for sealing the opening 111. The sealing body 12 corresponds to the one of the case walls 12. The case body 11 corresponds to the other case walls 11 (11A, 11B, 11C, 11D, 11E). The battery case 1 is made of, for example, aluminum or an aluminum alloy. The battery case 1 is not limited to the above form as long as the inside of the battery case 1 is airtight.

[0017] The electrode body 2 is housed in the battery case 1, with the positive electrode body 21 and the negative electrode body 22 stacked with a separator 23 sandwiched therebetween. The positive electrode body 21 and the negative electrode body 22 have active material-coated portions 212 and 222 in which the active materials KT1 and KT2 are coated on the electrode foils 21K and 22K, respectively, and active material-uncoated portions 211 and 221 in which the active materials KT1 and KT2 are not coated on one ends 21K1 and 22K1 of the electrode foils 21K and 22K.

[0018] The active material non-coated portion 211 of the positive electrode body 21 and the active material non-coated portion 221 of the negative electrode body 22 are disposed so as to face each other in the longitudinal direction (X direction) of the sealing body (one case wall portion) 12. The active material coated portions 212, 222 are formed on the other end portions 21K2, 22K2 and intermediate portions 21K3, 22K3 of the electrode foils 21K, 22K. Here, the electrode body 2 is formed by stacking the positive electrode body 21 and the negative electrode body 22 with the separator 23 sandwiched therebetween and winding them in a flat shape, but the sheet-like positive electrode body 21 and the negative electrode body 22 may also be stacked in a planar shape with the separator 23 sandwiched therebetween.

[0019] For example, in a lithium ion secondary battery, which is an example of the sealed storage battery 10, the electrode foil 21K of the positive electrode body 21 is made of, for example, aluminum foil, and the active material KT1 applied thereto is, for example, lithium transition metal oxide (LiNi 1 / 3 Co 1 / 3Mn 1 / 3 For example, a copper foil may be used as the electrode foil 22K of the negative electrode body 22, and for example, graphite, hard carbon, soft carbon, etc. may be used as the active material KT2 to be applied thereto. For example, a porous sheet of polypropylene resin, polyethylene resin, etc. may be used as the separator 23. For the electrolyte, a known non-aqueous electrolyte may be used.

[0020] The current collecting terminal 4 has a positive current collecting terminal 4A and a negative current collecting terminal 4B. The positive current collecting terminal 4A is made of aluminum, for example, and the negative current collecting terminal 4B is made of copper, for example. The positive and negative current collecting terminals 4 (4A, 4B) each have a base portion 41, a base adjacent portion 42, and a lead portion 43 that are integrally formed. Here, the base portion 41 is joined to the back side of both ends 12R in the longitudinal direction (X direction) of the sealing body (one case wall portion) 12 with the insulating member 3 interposed therebetween, but this is not necessarily limited to this. For example, the base portion 41 may be joined to the back side of both ends in the longitudinal direction (X direction) of the case main body (other case wall portion) 11 with the insulating member 3 interposed therebetween.

[0021] Moreover, the base adjacent portion 42 is adjacent to the base portion 41 and abuts against the insulating member 3. Here, the lead portion 43 is bent from the base adjacent portion 42 toward the bottom of the case (Z direction) at the position of the lead upper end portion 43a located above the case. The electrode foils 21K, 22K of the active material non-coated portions 211, 221 of the electrode body 2 are welded and joined to the lead lower end portion 43b located below the case of the lead portion 43 in an overlapping state (foil collected state), and are electrically connected.

[0022] The base portion 41 is connected to an external connection portion 45 located on the surface side of the sealing body (one case wall portion) 12 by, for example, a crimping pin 46 or the like. An insulating member 3 also serving as a sealant is interposed between the crimping pin 46 and the external connection portion 45 and the sealing body (one case wall portion) 12. For example, polyphenylene sulfide (PPS) resin can be used as the insulating member 3. When a plurality of sealed storage batteries 10 are connected, a bus bar (not shown) for connection is connected to the external connection portion 45. The external connection portion 45 may be formed integrally with the base portion 41. In this case, the sealing body (one case wall portion) 12, the external connection portion 45, and the base portion 41 may be insert-molded into the insulating member 3.

[0023] In addition, between the sealing body (one case wall part) 12 located above the battery case 1 and the upper end part 24 of the electrode body 2, there is provided a shielding film 7 that prevents the electrolyte 5 injected from the injection port 121 from adhering to the back surface 12b side of the sealing body (one case wall part) 12. The shielding film 7 has a nozzle insertion opening 7P formed at a position opposite the injection port 121, through which an injection nozzle 6 for the electrolyte 5 is inserted.

[0024] Here, the shielding film 7 is formed of a resin film such as polypropylene resin, but is not necessarily limited to a resin film. In addition, the nozzle insertion opening 7P is preferably formed in a circular shape with an inner diameter equal to or larger than the inner diameter of the injection opening 121. This is to absorb the positional deviation of the shielding film 7 relative to the battery case 1. The nozzle insertion opening 7P does not necessarily have to be limited to a circular shape, and may be, for example, an oval or elliptical shape that is long in a direction perpendicular to the electrolyte discharge direction (X direction) of the injection nozzle 6. In this case, since the gap with the injection nozzle 6 is wide in the major axis direction, the injection nozzle 6 is unlikely to interfere with the shielding film 7, and since the gap with the injection nozzle 6 is narrow in the minor axis direction, the electrolyte 5 is unlikely to splash from the gap to the back surface 12b side of the sealing body (one case wall part) 12.

[0025] This shielding film 7 can prevent the electrolyte 5 from adhering to the back surface 12b of the sealing body (one case wall part) 12 even if the electrolyte 5 adheres to the shielding film 7 when the electrolyte 5 is injected into the battery case 1. Therefore, even if the sealing body (one case wall part) 12 is heated by the welding heat for welding the injection port 121 and the plug 122, the electrolyte 5 adhered to the shielding film 7 hardly increases in temperature and is not easily vaporized. As a result, the pressure inside the battery case 1 is not easily increased, so that the gas inside the battery case 1 can be prevented from penetrating the welded part 123 between the injection port 121 and the plug 122, which causes defects such as pinholes. Therefore, a high-quality sealed storage battery 10 that can improve the sealing property inside the battery case 1 can be provided.

[0026] Moreover, the sealed storage battery 10 preferably includes an insulating film 8 interposed between the electrode body 2 and another case wall 11 constituting the battery case 1, and the shielding film 7 extends from one end 84 of the insulating film 8 and is connected to the other end 85. Here, the other case wall 11 corresponds to a pair of long side wall portions 11A, 11B, a pair of short side wall portions 11C, 11D, and a bottom wall portion 11E of the case body 11. The insulating film 8 is formed as a bottomed rectangular cylinder surrounding each side surface and the bottom surface of the electrode body 2, and the shielding film 7 is formed as a shield having a convex cross section protruding toward the back surface 12b of the sealing body (one case wall portion) 12.

[0027] By connecting the shielding film 7 to the insulating film 8, the shielding film 7 can be stably attached between the sealing body (one case wall part) 12 and the electrode body 2, and the shielding performance of the shielding film 7 can be improved. In addition, the shielding film 7 is formed as a shielding body with a convex cross section protruding toward the back surface 12b side of the sealing body (one case wall part) 12, so that it is difficult to droop toward the electrode body 2 side. Therefore, the shielding film 7 can more reliably prevent the electrolyte 5 discharged from the discharge port 61 formed in the side wall of the injection nozzle 6 from scattering toward the back surface 12b side of the sealing body (one case wall part) 12. As a result, the electrolyte 5 can be suppressed from adhering to the back surface 12b side of the sealing body (one case wall part) 12.

[0028] Here, as shown in the development view of FIG. 5, the shielding film 7 and the insulating film 8 are formed from a single film material. The insulating film 8 includes a long side film 81, a short side film 83, and a bottom film 82, which face a pair of long side wall portions 11A and 11B, a pair of short side wall portions 11C and 11D, and a bottom wall portion 11E of the case body 11. The insulating film 8 has mountain fold lines Q1, Q3, Q4, and Q5, and a valley fold line Q2. The insulating film 8 is folded along each of the fold lines Q1, Q2, Q3, Q4, and Q5 to form a bottomed rectangular tube that surrounds the electrode body 2. Here, the short side film 83 is two-ply, and the short side films 83 are connected to each other at appropriate positions by heat welding or the like.

[0029] The shielding film 7 has an overlapping portion 72 that extends from one end 84 extending in the longitudinal direction of one long side film 81 and is connected in a double-layered manner to the other end 85 extending in the longitudinal direction of the other long side film 81. The other end 85 of the long side film 81 is connected to the overlapping portion 72 by, for example, thermal welding. A nozzle insertion port 7P is formed in the shielding portion 71 of the shielding film 7 at a position opposite the injection port 121. Here, the shielding film 7 and the insulating film 8 are formed from a single film material, but the shielding film 7 and the insulating film 8 may be formed from separate film materials.

[0030] It is preferable that the shielding film 7 shields substantially the entire back surface 12b side of the sealing body (one case wall part) 12, except for the terminal joint parts where the positive and negative current collecting terminals 4 (4A, 4B) are joined. This is to avoid the possibility that the electrolyte 5 attached to both longitudinal ends 12R of the sealing body (one case wall part) 12 may move to the periphery of the injection port 121 and be vaporized due to, for example, shaking or vibration during transportation. Here, the shielding film 7 is extended to both longitudinal ends 12R of the sealing body (one case wall part) 12, and notches 73 are formed along the base parts 41 and base adjacent parts 42 of the current collecting terminals 4 at both longitudinal ends of the shielding film 7.

[0031] In addition, in the present sealed storage battery 10, the sealing body (one case wall part) 12 is provided with a safety valve 124 formed so as to be able to open in response to an increase in pressure inside the battery case 1, and the shielding film 7 is preferably provided with a slit groove 7M at a position opposite the safety valve 124, which is broken when the safety valve 124 is opened. The safety valve 124 is a known safety valve formed integrally with the sealing body (one case wall part) 12, but may be formed separately. The slit groove 7M is preferably formed so as not to penetrate the shielding film 7 in the plate thickness direction, but may penetrate the shielding film 7 in the plate thickness direction in the form of perforations, for example. By providing the shielding film 7 with the slit groove 7M which is broken when the safety valve 124 is opened, it is possible to smoothly release gas when the safety valve 124 is activated while suppressing adhesion of the electrolyte 5 to the back surface 12b side of the sealing body (one case wall part) 12. Also, the slit groove 7M may be formed such that the slit groove 7M1 in the longitudinal direction (X direction) and the slit groove 7M2 in the lateral direction (Y direction) intersect in a substantially H-shape, for example. This is because the opening area of ​​the slit groove 7M increases when it is broken, allowing gas to be released more efficiently.

[0032] In addition, in the present sealed storage battery 10, the shielding film 7 is preferably formed of a material having a thermal conductivity lower than that of the sealing body (one case wall part) 12. In this case, even if the shielding film 7 is in contact with the sealing body (one case wall part) 12, the electrolyte 5 attached to the shielding film 7 is unlikely to be heated and the electrolyte 5 is unlikely to be vaporized even if the sealing body (one case wall part) 12 is heated by the welding heat for welding the injection port 121 and the plug 122. Therefore, the pressure inside the battery case 1 is unlikely to increase, and it is possible to further prevent the gas inside the battery case 1 from entering the welded part 123 between the injection port 121 and the plug 122 and causing defects such as pinholes.

[0033] <Manufacturing method of this sealed storage battery> Next, a method for manufacturing a sealed storage battery according to another embodiment of the disclosed technique will be described in detail with reference to the drawings. Fig. 6 shows a flow chart illustrating a method for manufacturing the sealed storage battery shown in Fig. 1. Fig. 7 shows a schematic cross-sectional view along CC in Fig. 4, illustrating a state in which an electrolyte is injected into a battery case in an electrolyte injection step shown in Fig. 6. Fig. 8 shows a schematic cross-sectional view along CC in Fig. 4, illustrating a state in which a boundary between an injection port and a plug is welded in a plug welding step shown in Fig. 6.

[0034] The manufacturing method of the present sealed storage battery 10 includes an electrolyte injection step S1 and a plug welding step S2, as shown in Fig. 6. The electrolyte injection step S1 is a step of injecting electrolyte 5 into the battery case 1 from an injection nozzle 6 inserted into a gap between the shielding film 7 and the electrode body 2 through an injection port 121 after the electrode body 2 is housed in the battery case 1, as shown in Fig. 7, and the plug welding step S2 is a step of welding the injection port 121 and the plug 122 together after the electrolyte injection step S1, as shown in Fig. 8.

[0035] Here, the present sealed storage battery 10 includes a battery case 1 and an electrode body 2 housed in the battery case 1, a sealing body (one case wall) 12 constituting the battery case 1 includes an injection port 121 for injecting an electrolyte 5 into the battery case 1 and a plug 122 for sealing the injection port 121 by welding, and a shielding film 7 for blocking the electrolyte 5 injected from the injection port 121 from adhering to the back surface 12b side of the sealing body (one case wall) 12 is provided between the sealing body (one case wall) 12 and the electrode body 2, and a nozzle insertion port 7P for inserting an injection nozzle 6 for the electrolyte 5 is formed in the shielding film 7 at a position opposite the injection port 121. The technical contents of the present sealed storage battery 10 have already been described in detail, so they will not be described here.

[0036] As shown in FIG. 7, a circular outlet 61 for discharging the electrolyte 5 into the gap between the shielding film 7 and the electrode body 2 is opened in the side wall of the injection nozzle 6 in the longitudinal direction (X direction) of the sealing body (one case wall part) 12. The electrolyte 5 is radially scattered from the outlet 61 in the longitudinal direction (X direction) of the sealing body (one case wall part) 12. The relationship between the position and hole diameter of the outlet 61 of the injection nozzle 6 and the size of the nozzle insertion hole 7P is set so that the electrolyte 5 scattered radially does not scatter from the nozzle insertion hole 7P of the shielding film 7 to the back surface 12b side of the sealing body (one case wall part) 12. The injection nozzle 6 is connected to a supply device (not shown) for the electrolyte 5. In the electrolyte injection process S1, a required amount of electrolyte 5 supplied from the supply device is injected into the battery case 1 from the injection nozzle 6 inserted into the gap between the shielding film 7 and the electrode body 2 from the injection hole 121.

[0037] As shown in FIG. 8, the injection port 121 has a large-diameter plug joint hole 121a that is joined to the plug 122 and a small-diameter nozzle insertion hole 121c through which the injection nozzle 6 is inserted, which are formed in a stepped shape. Between the plug joint hole 121a and the nozzle insertion hole 121c, an annular flange portion 121b that abuts against the back surface of the plug 122 is formed. In the plug welding step S2, after the electrolyte injection step S1, the plug 122 is inserted into the plug joint hole 121a of the injection port 121, and the inner circumference of the plug joint hole 121a and the outer circumference of the plug 122 are butt-welded to form a welded portion 123 over the entire boundary between the injection port 121 and the plug 122. Note that the welding method for the butt welding is preferably, for example, a laser welding method in which a laser beam 91 from a fiber laser welder 9 is irradiated from the surface 12a side of the sealing body (one case wall portion) 12. This is because the amount of heat input to the sealing body (first case wall portion) 12 is small, and welding can be performed in a short time.

[0038] According to the manufacturing method of the sealed storage battery 10, when the electrolyte 5 is injected into the battery case 1 in the electrolyte injection step S1, the shielding film 7 can prevent the electrolyte 5 from adhering to the back surface 12b side of the sealing body (one case wall part) 12. Therefore, even if the sealing body (one case wall part) 12 is heated in the plug welding step S2 for welding the injection port 121 and the plug 122 after the electrolyte injection step S1, the electrolyte 5 is unlikely to evaporate. As a result, the pressure inside the battery case 1 is unlikely to increase, so that the gas inside the battery case 1 can be prevented from entering the welded part 123 between the injection port 121 and the plug 122, which can prevent defects such as pinholes from occurring. Therefore, a manufacturing method of a high-quality sealed storage battery 10 capable of improving the sealing property inside the battery case 1 can be provided.

[0039] In addition, in the manufacturing method of the present sealed storage battery 10, it is preferable that the insulating film 8 is interposed between the electrode body 2 and another case wall 11 constituting the battery case 1, and the shielding film 7 is extended from one end 84 of the insulating film 8 and connected to the other end 85. Here, the other case wall 11 corresponds to a pair of long side wall portions 11A, 11B, a pair of short side wall portions 11C, 11D, and a bottom wall portion 11E of the case body 11. The insulating film 8 is formed as a bottomed rectangular cylinder surrounding each side surface and the bottom surface of the electrode body 2, and the shielding film 7 is formed as a shielding body with a convex curved cross section that protrudes toward the back surface 12b side of the sealing body (one case wall portion) 12.

[0040] In this case, by connecting the shielding film 7 to the insulating film 8, the shielding film 7 can be stably attached between the sealing body (one case wall part) 12 and the electrode body 2, and the shielding performance of the shielding film 7 can be improved. In addition, since the shielding film 7 is formed as a shielding body with a convex curved cross section protruding toward the back surface 12b side of the sealing body (one case wall part) 12, it is difficult to droop toward the electrode body 2 side. Therefore, the shielding film 7 can more reliably prevent the electrolyte 5 discharged from the discharge port 61 formed on the side wall of the injection nozzle 6 from scattering toward the back surface 12b side of the sealing body (one case wall part) 12. As a result, the electrolyte 5 can be stably prevented from adhering to the back surface 12b side of the sealing body (one case wall part) 12.

[0041] In addition, in the manufacturing method of the sealed storage battery 10, the sealing body (one case wall part) 12 is provided with a safety valve 124 formed so as to be able to open as the pressure inside the battery case 1 rises, and the shielding film 7 is preferably provided with a slit groove 7M at a position opposite the safety valve 124, which is broken when the safety valve 124 is opened. The slit groove 7M is preferably formed so as not to penetrate the shielding film 7 in the plate thickness direction, but may penetrate the shielding film 7 in the plate thickness direction in the form of perforations, for example. In this case, by providing the shielding film 7 with the slit groove 7M which is broken when the safety valve 124 is opened, in the electrolyte injection step S1, it is possible to smoothly release gas when the safety valve 124 is activated while suppressing adhesion of the electrolyte 5 to the back surface 12b side of the sealing body (one case wall part) 12. Note that the slit groove 7M may be formed, for example, so that the slit groove 7M1 in the longitudinal direction (X direction) and the slit groove 7M2 in the lateral direction (Y direction) intersect in a substantially H-shape. This is because the opening area of ​​the slit groove 7M increases when it is broken, allowing gas to be released more efficiently.

[0042] In addition, in the manufacturing method of the present sealed storage battery 10, the shielding film 7 is preferably formed of a material having a thermal conductivity lower than that of the sealing body (one case wall part) 12. In this case, even if the shielding film 7 is in contact with the sealing body (one case wall part) 12 in the plug welding step S2, the electrolyte 5 attached to the shielding film 7 is unlikely to be heated and the electrolyte 5 is unlikely to be vaporized even if the sealing body (one case wall part) 12 is heated by the welding heat for welding the injection port 121 and the plug 122. Therefore, the pressure inside the battery case 1 is unlikely to increase, and it is possible to further prevent the gas inside the battery case 1 from entering the welded part 123 between the injection port 121 and the plug 122 and causing defects such as pinholes.

[0043] <Modification> The above-described embodiment is merely an example and does not limit the disclosed technology in any way. Therefore, the disclosed technology can be improved or modified in various ways without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0044] 1 Battery case 2 Electrode body 5 Electrolyte 6 Injection nozzle 7. Shielding film 7P Nozzle insertion hole 7M slit groove 8. Insulating film 10. Sealed batteries 11 Other case walls, case body 12 First case wall, sealing body 84 One end 85 Other end 12b Back 121 Inlet 122 Plug body 124 Safety valve S1 Electrolyte injection process S2 plug welding process

Claims

1. A battery case; An electrode assembly housed in the battery case, one case wall portion constituting the battery case has an injection port for injecting an electrolyte into the battery case and a plug for sealing the injection port by welding, a shielding film is provided between the one case wall and the electrode body to prevent the electrolyte injected from the injection port from adhering to a back surface side of the one case wall; The shielding film has a nozzle insertion hole formed at a position opposite to the injection hole, through which an injection nozzle for the electrolyte is inserted. Sealed storage battery.

2. 2. The sealed storage battery according to claim 1, an insulating film interposed between the electrode body and another case wall portion constituting the battery case, The shielding film is extended from one end of the insulating film and connected to the other end. Sealed storage battery.

3. 2. The sealed storage battery according to claim 1, the one case wall portion is provided with a safety valve formed to be able to open in response to an increase in pressure inside the battery case, The shielding film has a slit groove at a position opposite to the safety valve, the slit groove being broken when the safety valve is opened. Sealed storage battery.

4. The sealed storage battery according to any one of claims 1 to 3, The shielding film is formed of a material having a thermal conductivity lower than that of the first case wall portion. Sealed storage battery.

5. A battery case; An electrode assembly housed in the battery case, one case wall constituting the battery case has an injection port for injecting an electrolyte into the battery case and a plug for sealing the injection port by welding; a shielding film is provided between the one case wall and the electrode body to prevent the electrolyte injected from the injection port from adhering to a back surface side of the one case wall; a nozzle insertion hole through which an injection nozzle for the electrolyte is inserted is formed in the shielding film at a position opposite to the injection hole; an electrolyte injection step of injecting the electrolyte into the battery case from the injection nozzle inserted into a gap between the shielding film and the electrode body through the injection port after the electrode body is housed in the battery case; and a plug welding step of welding the injection port and the plug after the electrolyte injection step. A method for manufacturing a sealed storage battery.

6. The method for producing a sealed storage battery according to claim 5, an insulating film interposed between the electrode body and another case wall portion constituting the battery case, The shielding film is extended from one end of the insulating film and connected to the other end. A method for manufacturing a sealed storage battery.

7. 6. The sealed storage battery according to claim 5, the one case wall portion is provided with a safety valve formed to be able to open in response to an increase in pressure inside the battery case, The shielding film has a slit groove at a position opposite to the safety valve, the slit groove being broken when the safety valve is opened. A method for manufacturing a sealed storage battery.

8. The method for producing a sealed storage battery according to any one of claims 5 to 7, The shielding film is formed of a material having a thermal conductivity lower than that of the first case wall portion. A method for manufacturing a sealed storage battery.

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