JP5508768B2 - Sealed battery - Google Patents

Description

  The present invention relates to a sealed battery, and more particularly, to a sealed battery including an electrode group, a bottomed container, a lid, and a current collecting component, and the container and the lid also serve as terminals having different polarities.

  In a conventional cylindrical battery representing a sealed battery, an electrode group in which a positive electrode and a negative electrode are wound through a separator is housed in a bottomed cylindrical container. One of the positive electrode and the negative electrode is connected to the container, and the other is connected to the lid. The opening of the container is sealed and sealed with a lid through an electrically insulating gasket (packing). In the seal portion, generally, a narrowing process is performed on the opening side of the container, and a gasket made of rubber or plastic resin is arranged on the opening side (upper side when the container is stood) from the constricted portion inside the container. A lid is arranged on the upper side of the gasket, and the opening end of the container is bent inward, that is, the lid is caulked and fixed to the container, and the container is sealed.

  In such a cylindrical battery, since the container and the lid body also serve as terminals having different polarities, electrical insulation between the container and the lid body is ensured by the gasket. Further, in order to ensure electrical insulation between the electrode group housed in the container and the container, a technique of a cylindrical battery in which an insulating tape is wound on the electrode group is disclosed (for example, a patent) Reference 1).

JP 11-339768 A

  However, in a general cylindrical battery, a plurality of strip-shaped tabs are led out from a positive electrode and a negative electrode, respectively, and the tabs are connected to a container or a lid, respectively. For this reason, when the cylindrical battery receives an unexpected external force due to excessive vibration or impact, the tab of the positive electrode or the negative electrode may be cut. Also, the detached tab may move within the battery. In particular, when the tab connected to the lid is cut, even if the insulating tape is wound on the electrode group as in Patent Document 1, depending on the position, the tab may be attached to the container that also serves as a terminal having a different polarity from the lid. May come into contact. Therefore, it is important to ensure electrical insulation even when an unexpected external force is applied, in order to improve battery reliability as well as ensuring battery performance.

  In view of the above-described case, an object of the present invention is to provide a sealed battery that can ensure electrical insulation between different electrodes and improve battery reliability.

In order to solve the above-mentioned problems, the present invention includes an electrode group in which positive and negative electrodes are wound via a separator, the electrode group is accommodated, and a constricted portion protruding in the center direction is formed on the opening side, A bottomed container that also serves as one of the terminals of the positive and negative electrodes, and a lid that is caulked and fixed to the opening side from the constricted portion of the container via an electrically insulating gasket, and also serves as the other terminal of the positive and negative electrodes; , it is opposed to an end face of the cover side of the electrode group, and a bonded collector parts plurality of the tip outer peripheral surface of the tab which is derived from the other of the positive and negative electrode, the current collector The component has a diameter smaller than the diameter of the electrode group, and is arranged such that the outer peripheral surface is located on the center side of the constricted portion of the container, and the outer periphery of the electrode group on the lid side Around a plurality of tabs joined to the outer peripheral surface of the current collecting component An electrically insulating film is arranged so as to cover, and the end of the film on the lid side is located on the lid side beyond the constricted portion of the container, and the film is disposed on the outer periphery of the electrode group. The sealed battery is characterized in that only the portion positioned is fixed to the electrode group, and the end on the lid side is arranged to have a diameter smaller than the diameter of the electrode group .

In the present invention, since the lid side end of the electrically insulating film disposed on the outer periphery of the electrode group on the lid side is located on the lid side beyond the constricted portion of the container, the diameter is smaller than the diameter of the electrode group. Even if the tab joined to the current collecting component arranged so that the outer peripheral surface is located on the center side of the constricted portion of the container is cut by unexpected external force, the container serving as a terminal of different polarity and the cut tab The portion of the electrically insulating film located on the outer periphery of the electrode group is fixed to the electrode group, and the end on the lid side is arranged to have a diameter smaller than the diameter of the electrode group. Therefore, even if an unexpected external force is applied, it is held between the container and the tab or current collecting part without moving, ensuring electrical insulation between different poles and improving battery reliability. Can do.

In this case, it is possible to determine the end of the cover side of the full Irumu the position of the surface and non-contact of the electrode group side of the lid. The container may also serve as the negative electrode terminal, and the lid may also serve as the positive electrode terminal.

According to the present invention, since the end on the lid side of the electrically insulating film disposed on the outer periphery on the lid side of the electrode group is located on the lid side beyond the constricted portion of the container, the diameter is smaller than the diameter of the electrode group. Even if the tab joined to the current collector parts arranged so that the outer peripheral surface is located on the center side from the constricted part of the container is cut by unexpected external force, it was cut from the container that also serves as a terminal of different polarity Arrangement is made so that contact with the tab is prevented, and only the portion of the electrically insulating film located on the outer periphery of the electrode group is fixed to the electrode group, and the end on the lid side is smaller in diameter than the electrode group. since it was, because it is held between the container and the tab and collector parts without unexpected external force moves also act, improved battery reliability to ensure electrical insulation between different poles The effect that it can be made can be acquired.

It is sectional drawing which shows typically the cylindrical lithium ion secondary battery of embodiment to which this invention is applied. The positive electrode plate and negative electrode plate which comprise the cylindrical lithium ion secondary battery of embodiment are shown typically, (A) is a top view of a positive electrode plate, (B) is sectional drawing of a positive electrode plate, (C) is a negative electrode plate (D) is sectional drawing of a negative electrode plate. It is a fragmentary sectional view which expands a part by the side of the positive electrode of the cylindrical lithium ion secondary battery of embodiment, and shows arrangement | positioning of an insulating tape. It is a fragmentary sectional view which expands a part by the side of the negative electrode of the cylindrical lithium ion secondary battery of embodiment, and shows arrangement | positioning of an insulating tape. FIG. 3 is a partial cross-sectional view showing the connection form between the battery lid and electrode group of the cylindrical lithium ion secondary battery of Example 1 and the arrangement of the insulating film. 3 is a partial cross-sectional view showing the positional relationship between the outermost peripheral positive electrode tab and the insulating tape in the cylindrical lithium ion secondary battery of Example 1. FIG. FIG. 3 is a partial cross-sectional view schematically showing a moving range when an outermost peripheral positive electrode tab in the cylindrical lithium ion secondary battery of Example 1 is cut. 3 is a partial cross-sectional view showing a lower limit position of an end position of an insulating tape in the cylindrical lithium ion secondary battery of Example 1. FIG. 3 is a partial cross-sectional view schematically showing a moving range of an insulating tape in a cylindrical lithium ion secondary battery of Example 1. FIG. 3 is a partial cross-sectional view showing an upper limit position of an end position of an insulating tape in the cylindrical lithium ion secondary battery of Example 1. FIG. 4 is a partial cross-sectional view showing a positional relationship between an outermost peripheral positive electrode tab and an insulating tape in a cylindrical lithium ion secondary battery of Example 2. FIG. 6 is a partial cross-sectional view schematically showing a moving range when an outermost peripheral positive electrode tab in a cylindrical lithium ion secondary battery of Example 2 is cut. FIG. 4 is a partial cross-sectional view schematically showing a positional relationship and a dimensional relationship between an outermost peripheral positive electrode tab and an insulating tape in a cylindrical lithium ion secondary battery of Example 2. FIG. It is a fragmentary sectional view which shows arrangement | positioning of the insulating tape in the conventional cylindrical lithium ion secondary battery. It is a fragmentary sectional view which shows typically the state which contacted the battery container when the positive electrode tab of the cylindrical lithium ion secondary battery of FIG. 14 was cut | disconnected by unexpected external force. It is a fragmentary sectional view which shows arrangement | positioning of the insulating tape in another aspect of the conventional cylindrical lithium ion secondary battery. It is a fragmentary sectional view which shows arrangement | positioning of the insulating tape and gasket in another aspect of the conventional cylindrical lithium ion secondary battery.

  Embodiments of a cylindrical lithium ion secondary battery to which the present invention is applied will be described below with reference to the drawings.

(Constitution)
As shown in FIG. 1, a cylindrical lithium ion secondary battery 20 of the present embodiment includes a battery container 1 made of metal and having a bottomed cylindrical shape. The battery container 1 accommodates an electrode group 8 in which a positive electrode plate (positive electrode) and a negative electrode plate (negative electrode) are arranged via a separator.

  In the electrode group 8, the positive electrode plate and the negative electrode plate are wound through a microporous separator made of polyethylene or the like so that the two electrode plates do not directly contact each other. A tubular shaft core 7 made of resin is used at the winding center. That is, in the electrode group 8, the positive electrode plate and the negative electrode plate are wound around the shaft core 7 in a spiral shape through the separator. The positive electrode tab (tongue piece) 9c derived from the positive electrode plate and the negative electrode tab (tongue piece) 10c derived from the negative electrode plate are wound so as to protrude in opposite directions from both ends in the width direction of the separator, respectively. It is arranged on both end surfaces of the electrode group 8 opposite to each other.

  On the upper side of the electrode group 8, an annular positive electrode current collecting component 5 for collecting the electric potential from the positive electrode plate substantially on the extension line of the shaft core 7 is opposed to one end (battery cover side) end surface of the electrode group 8. Are arranged to be. As shown in FIG. 3, the positive electrode current collecting component 5 has a cylindrical portion 5a protruding on the opposite side of the electrode group 8 on the outer edge portion of the annular flat plate, and a cylindrical portion 5b protruding on the electrode group 8 side in the center portion. doing. The outer diameter of the positive electrode current collector 5 is formed smaller than the outer diameter of the electrode group 8. As shown in FIG. 1, the positive electrode current collecting component 5 is fixed to the upper end portion of the shaft core 7 by fitting. That is, the cylindrical portion 5 b is fitted in the tubular portion of the shaft core 7. On the outer peripheral surface of the cylindrical portion 5a, the tip portions of all the positive electrode tabs 9c are gathered and joined by ultrasonic welding or the like. A disc-shaped battery lid serving as a positive electrode external terminal is disposed above the positive electrode current collecting component 5.

  The battery lid is composed of a plurality of parts including a part having a safety valve (valve mechanism). In other words, the battery lid includes a metal disc-like upper lid 3 and a metal disc-like upper lid case 4. The outer periphery of the upper lid 3 is fixed by caulking at the outer periphery of the upper lid case 4. The upper lid 3 has a cylindrical protrusion protruding upward at the center, and an opening is formed on the upper surface of the protrusion. A gas discharge valve (hereinafter referred to as a discharge valve) is formed at the center of the upper lid case 4 to release the internal pressure when the battery internal pressure rises during an abnormality. One end of the positive electrode lead 14 is bonded to the upper part of the positive electrode current collecting component 5, and the other end of the positive electrode lead 14 is bonded to the lower surface of the upper lid case 4. For this reason, the positive electrode plate constituting the electrode group 8 and the upper lid 3 constituting the battery lid are electrically connected via the positive electrode current collecting component 5, the positive electrode lead 14 and the upper lid case 4.

  The battery lid is caulked and fixed to the opening of the battery container 1 via the gasket 2. For the gasket 2, for example, a resin material such as polypropylene or a material having electrical insulation properties such as a rubber material is used. The gasket 2 plays a role of electrically insulating the battery container 1 and the battery lid. As shown in FIG. 1, the battery container 1 is subjected to a constricting process from the open end to the container bottom surface, and a constricted portion is formed. In the constricted portion, the battery case 1 protrudes toward the inner side (center side), and a depression is formed on the outer periphery of the battery case 1 over the entire circumference. The constricted portion is formed to face the outer peripheral surface of the cylindrical portion 5 a of the positive electrode current collector component 5. In other words, the positive electrode current collector component 5 is arranged so that the outer peripheral surface of the cylindrical portion 5a is positioned closer to the battery center than the protruding end of the constricted portion. The gasket 2 is disposed on the inner side of the battery container 1 and above the constricted portion (opening end side). The battery lid is disposed on the upper side of the gasket 2. The opening end of the battery case 1 and a part of the gasket 2 are bent inward (inside down) so as to be along the peripheral edge (the upper surface) of the battery cover, and the battery cover is caulked and fixed to the battery case 1. At this time, the gasket 2 is bent in a U-shaped cross section so as to cover both sides of the peripheral edge of the battery lid.

  On the other hand, a negative electrode current collecting component 6 for collecting a potential from the negative electrode plate is disposed below the electrode group 8 so as to face the other end (bottom side of the container) end face of the electrode group 8. As shown in FIG. 4, the negative electrode current collector component 6 has a cylindrical portion 6 a that protrudes on the outer edge of the annular flat plate on the side opposite to the electrode group 8 (inner bottom side of the battery container 1). The lower end portion of the shaft core 7 is fixed to the inner peripheral surface of the negative electrode current collector component 6 by fitting. In other words, the negative electrode current collector component 6 is externally attached to the lower end portion of the shaft core 7. On the outer peripheral surface of the cylindrical portion 6a, the tip portions of all the negative electrode tabs 10c are gathered and joined by ultrasonic welding or the like. The lower part of the negative electrode current collector component 6 is joined to the inner bottom portion of the battery container 1 serving also as a negative electrode external terminal via a negative electrode lead 15 by welding. Therefore, the negative electrode plate constituting the electrode group 8 and the battery container 1 are electrically connected via the negative electrode current collector 6 and the negative electrode lead 15. In other words, in the lithium ion secondary battery 20, the battery lid also serves as the positive external terminal and the battery container 1 also serves as the negative external terminal, and the battery lid and the battery container 1 constitute external terminals having different polarities. Yes.

  Between the electrode group 8 and the battery case 1, an insulating tape (electrical insulating film) 12 is disposed on the battery lid side, that is, the positive electrode side, and an insulating tape (electrical insulating film) 13 is disposed on the inner bottom side, that is, the negative electrode side. ing. The insulating tapes 12 and 13 are respectively wound on both end sides of the electrode group 8, and both are made of a material such as polyimide having electrical insulating properties. The insulating tape 12 keeps electrical insulation between the battery container 1 and the positive current collecting component 5 and the positive electrode tab 9c, and the insulating tape 13 between the battery container 1 and the negative current collecting component 6 and the negative electrode tab 10c. Is blocked.

  As shown in FIG. 3, the insulating tape 12 is disposed so as to cover the positive electrode tab 9 c bonded to the positive electrode current collector component 5 from the end portion of the electrode group 8 on the battery lid side. At the end of the electrode group 8 on the battery lid side, the insulating tape 12 is bonded to a separator located on the outermost periphery of the electrode group 8 with, for example, an adhesive such as hexamethacrylate. That is, the insulating tape 12 and the separator overlap at the end of the electrode group 8 on the battery lid side. The insulating tape 12 is disposed without bonding a portion located on the battery lid side from one end face of the electrode group 8. In other words, only the portion of the insulating tape 12 located on the outer periphery of the electrode group 8 is fixed to the electrode group 8. Since the outer diameter of the positive electrode current collecting component 5 is smaller than the outer diameter of the electrode group 8, the positive electrode tab derived from the outer peripheral side of the electrode group 8 (outside the position of the outer peripheral surface of the cylindrical portion 5 a of the positive electrode current collecting component 5). 9c is joined to the positive electrode current collecting component 5 so as to be inclined. For this reason, in the insulating tape 12 arranged so as to cover the positive electrode tab 9c, the portion located closer to the battery lid than the electrode group 8, that is, the non-adhered portion is arranged so that the diameter becomes smaller toward the battery lid. . That is, the end of the insulating tape 12 on the battery lid side is smaller in diameter than the outer diameter of the electrode group 8.

  Further, the end of the insulating tape 12 on the upper lid case 4 side is located between the protruding end of the constricted portion of the battery case 1 and the upper lid case 4. That is, the end of the insulating tape 12 on the battery lid side is located on the battery lid side beyond the protruding end of the constricted portion. The end position of the insulating tape 12 is determined at a position not in contact with the lower surface of the upper lid case 4 constituting the battery lid. This means that the end position of the insulating tape 12 can be adjusted by using the upper surface (end surface on the battery lid side) position 5d of the cylindrical portion 5a of the positive electrode current collecting component 5 as a reference. That is, among the many positive electrode tabs 9c, the calculation is performed with the setting that the outermost peripheral positive electrode tab 9d located at the outermost periphery is the longest. The lower limit position of the insulating tape 12 is set so that the outermost peripheral positive electrode tab 9d is not brought into contact with the inner surface of the battery container 1 even if the outer peripheral positive electrode tab 9d is cut at the connection end 9e indicating the end position connected to the positive electrode current collector component 5. Further, the position of the contact portion 2 a between the gasket 2 and the battery container 1 is set to the upper limit position of the insulating tape 12. This is because, since the gasket 2 and the battery container 1 constitute a battery sealing portion, if the insulating tape 12 is bitten by this portion, the sealing performance is affected.

  On the other hand, as shown in FIG. 4, the insulating tape 13 is arranged so as to cover the negative electrode tab 10 c joined to the negative electrode current collector component 6 from the end of the electrode group 8 on the inner bottom side of the container. At the end of the electrode group 8 on the inner bottom side of the container, the insulating tape 13 is bonded to a separator located on the outermost periphery of the electrode group 8. That is, the insulating tape 13 and the separator overlap each other at the end of the electrode group 8 on the inner bottom side of the container. The insulating tape 13 is disposed without bonding a portion located on the inner bottom side of the container from the other end face of the electrode group 8. In other words, only the portion of the insulating tape 13 located on the outer periphery of the electrode group 8 is fixed to the electrode group 8. The insulating tape 13 is adjusted so that the end position on the inner bottom side of the container is positioned near the inner bottom surface. In this example, since the battery container 1 also serves as the negative electrode external terminal and has the same polarity as the negative electrode current collector component 6 and the negative electrode tab 10c arranged on the inner bottom side of the container, the insulating tape is used like the above-described battery lid side. 13 end positions need not be set.

  As shown in FIGS. 2A and 2B, the positive electrode plate 9 constituting the electrode group 8 has an aluminum foil 9a as a positive electrode current collector. The positive electrode mixture 9b is applied substantially evenly on both surfaces of the aluminum foil 9a. An uncoated portion of the positive electrode mixture 9b is formed on the side edge on one side in the longitudinal direction of the aluminum foil 9a. The non-coated portion is cut out in a comb shape, and a large number of positive electrode tabs 9c are formed in the remaining portion of the cutout.

  On the other hand, as shown in FIGS. 2C and 2D, the negative electrode plate 10 has a copper foil 10a as a negative electrode current collector. On both surfaces of the copper foil 10a, the negative electrode mixture 10b is applied substantially evenly. A non-coated portion of the negative electrode mixture 10b is formed on the side edge on one side in the longitudinal direction of the copper foil 10a, similarly to the positive electrode plate 9, and a large number of negative electrode tabs 10c are formed.

  In addition, a nonaqueous electrolytic solution is injected into the battery container 1. As the non-aqueous electrolyte, a solution obtained by dissolving a lithium salt such as lithium hexafluorophosphate in a mixed organic solvent such as ethyl carbonate and dimethyl carbonate at a concentration of about 1 M / L (mol / liter) is used. . In the obtained lithium ion secondary battery 20, the battery lid is caulked and fixed to the opening of the battery container 7 so that the inside is sealed.

(Battery assembly)
In assembling the lithium ion secondary battery 20, first, the produced positive electrode plate 9 and negative electrode plate 10 are wound around the shaft core 7 through a separator to produce the electrode group 8. The positive electrode plate 9 and the negative electrode plate 10 are wound so that the positive electrode mixture 9b and the negative electrode mixture 10b are appropriately opposed to each other and the positive electrode tab 9c and the negative electrode tab 10c are positioned in opposite directions. After the positive electrode tab 9c and the negative electrode tab 10c arranged on both end faces of the produced electrode group 8 are welded to the positive electrode current collector component 5 and the negative electrode current collector component 6, respectively, the positive electrode current collector component 5 side and the negative electrode of the electrode group 8 The insulating tape 12 and the insulating tape 13 are wound around the current collecting component 6 side. After the electrode group 8 is inserted into the battery container 1 with the negative electrode current collector component 6 facing the bottom side, a welding electrode is inserted into the hollow portion of the tubular shaft core 7 and is welded to the negative electrode current collector component 6 in advance. The negative electrode lead 15 was joined to the inner bottom portion of the battery container 1 by resistance welding.

  The bottom end of the battery container 1 is slightly constricted from the opening end, and the other end of the positive electrode lead 14, which has been welded at one end to the positive electrode current collecting component 5 in advance, is joined to the lower surface of the battery lid (upper cover case 4) by welding. To do. After injecting a non-aqueous electrolyte into the battery container 1 and infiltrating the electrode group 8 into the non-aqueous electrolyte, the gasket 2 is disposed on the container opening side of the constricted portion inside the battery, and the upper side of the gasket 2 And a battery lid to which the positive electrode lead 14 is bonded. The opening end of the battery case 1 is bent and deformed inward, and the battery lid is caulked and fixed to the opening of the battery case 1 to complete the assembly of the lithium ion secondary battery 20.

  Next, an example of the cylindrical lithium ion secondary battery 20 produced according to the present embodiment will be given and the adjustment of the end position of the insulating tape 12 will be described in detail.

Example 1
As shown in FIG. 5, in the lithium ion secondary battery 20 of Example 1, the end position of the insulating tape 12 on the upper lid case 4 side is the end protruding from the inside of the constricted portion of the battery container 1 and the upper lid case 4. It adjusted so that it might be located between.

  As shown in FIG. 6, the outer diameter d1 of the positive electrode current collecting component 5 is φ28.06 mm, and the distance rd between the lead-out position of the outermost positive electrode tab 9d and the battery center is 19.2 mm. The distance h1 from the end position of the separator to the lower surface of the annular flat plate portion of the positive electrode current collector component 5 is 1.5 mm, and the height h2 of the cylindrical portion 5a of the positive electrode current collector component 5 is 5 mm. Further, the distance h3 from the end position of the separator to the lead-out end (root) 9f of the outermost peripheral positive electrode tab 9d is 4 mm, and the upper surface position 5d of the positive electrode current collector component 5 to the positive electrode current collector component 5 of the outermost peripheral positive electrode tab 9d. The distance h4 to the connection end 9e is 2.2 mm. Assuming that the outermost peripheral positive electrode tab 9d is arranged in the form shown in FIG. 6, the maximum length L is calculated to be 6.4 mm.

  As shown in FIG. 7, when the outermost peripheral positive electrode tab 9d is cut at the connection end 9e, it is assumed that the outermost positive electrode tab 9d has a circular motion around the lead-out end 9f, and the trajectory at the front end of the outermost peripheral positive electrode tab 9d has its maximum length. Draw as a circle with L as the radius. Further, the track of the tip of the insulating tape 12 is drawn as a circle centering on the contact portion 12a with the end position of the separator. Of the intersection points of the two circles, the position of the upper intersection point is set to the lower limit position of the tip 12b of the insulating tape 12. At the time of manufacturing the battery, as shown in FIG. 8, in the process of attaching the insulating tape 12 to the electrode group 8, the position shifted by 0.15 mm toward the electrode group 8 with respect to the upper surface position 5d of the positive electrode current collecting component 5 is set as the lower limit position. As you squeeze.

  The upper limit position of the tip 12b of the insulating tape 12 is set as follows. As shown in FIG. 9, the distal end portion of the insulating tape 12 is deformed along the constricted portion of the battery container 1. When the tip 12b is deformed beyond the position of the contact portion 2a between the gasket 2 and the battery case 1, the insulating tape 12 may be caught between the gasket 2 and the battery case 1 when the battery cover is fixed by caulking. There is. If the insulating tape 12 is bitten, battery sealing properties will be affected. In order to avoid this, the position of the contact portion 2a is set to the upper limit position of the tip 12b. At the time of manufacturing the battery, as shown in FIG. 10, in the step of attaching the insulating tape 12 to the electrode group 8, the position shifted by 0.85 mm toward the battery lid with respect to the upper surface position 5 d of the positive electrode current collecting component 5 is set as the upper limit position. Squeeze. That is, the insulating tape 12 is squeezed from the end of the electrode group 8, and the end position is in the range of 0.15 mm on the electrode group 8 side and 0.85 mm on the battery lid side with reference to the upper surface position 5d of the positive electrode current collector component 5. It is beaten so that it is located inside.

(Example 2)
In the lithium ion secondary battery 20 of Example 2, as in Example 1, the end position of the insulating tape 12 on the upper lid case 4 side is between the protruding end of the constricted part of the battery container 1 and the upper lid case 4. Adjusted to position. In Example 2, the outer diameter d1 of the positive electrode current collector component 5, the distance rd between the lead-out position of the positive electrode outermost peripheral tab 9d and the battery center, the distance from the end position of the separator to the lower surface of the annular portion of the positive electrode current collector component 5 h1, height h2 of the positive electrode current collector component 5, distance h3 from the end position of the separator to the lead-out end 9f of the outermost peripheral positive electrode tab 9d, positive electrode current collector of the outermost positive electrode tab 9d from the upper surface position 5d of the positive electrode current collector component 5 The distance h4 to the connection end 9e with respect to the component 5 was set to be the same as in Example 1.

  As shown in FIG. 11, when the bulging portion 9h is formed on the outermost peripheral positive electrode tab 9d, depending on the bulging length x, even if the upper limit position is set as in the first embodiment, the tip of the insulating tape 12 There is a possibility that the outermost peripheral positive electrode tab 9d contacts the battery container 1 beyond the position 12b. For this reason, it is necessary to limit the bulge length x of the bulge portion 9h to prevent the outermost peripheral positive electrode tab 9d from contacting the battery container 1 beyond the tip 12b.

  As shown in FIG. 12, when the outermost peripheral positive electrode tab 9d is cut at the connection end 9e, the outermost peripheral positive electrode tab 9d moves toward the tip 12b of the insulating tape 12 and becomes linear. In this case, the length to the front end 12b of the insulating tape 12 is determined as the upper limit value of the bulge length x of the bulge portion 9h.

  As shown in FIG. 13, the outer diameter d2 of the electrode group 8 is set to φ38.6 mm, and the inner diameter d3 of the battery container 1 is set to φ39 mm. In this case, the distance between the connection end 9e of the outermost peripheral positive electrode tab 9d to the positive electrode current collecting component 5 and the tip 12b of the insulating tape 12 is j, the distance between the lead-out end 9f and the tip 12b is k, and the lead-out end 9f to the connection end 9e. Is defined as the upper limit value, the bulge length x obtained by the equation x = (j + k−1) / 2. In this example, since the distance j is 2.69 mm, the distance k is 5.38 mm, and the distance l is 5.97 mm, the bulge length x of the bulge portion 9h is calculated to be 1.09 mm. It is determined as the upper limit value of the bulge length x. In other words, by limiting the bulge length x to the upper limit value or less, it is possible to prevent the outermost peripheral positive electrode tab 9d from contacting the battery container 1 beyond the tip 12b.

(Action etc.)
Next, the operation and the like of the cylindrical lithium ion secondary battery 20 of the present embodiment will be described focusing on the operation of the insulating tape 12.

  In the conventional cylindrical lithium ion secondary battery, as shown in FIG. 16, the electrode group 8 is accommodated in a bottomed cylindrical battery container 1, and the battery lid formed by the upper lid 3 and the upper lid case 4 is the container opening. It is caulked and fixed to the part via a gasket 2. A positive electrode tab 9 c led out from a positive electrode plate constituting the electrode group 8 is connected to the positive electrode current collector component 5, and the positive electrode current collector component 5 and the upper lid case 4 are connected by a positive electrode lead 14. Since the battery lid also serves as the positive electrode external terminal, it forms a different polarity from the battery container 1 that also serves as the negative electrode external terminal. For this reason, in order to ensure electrical insulation between the electrode group 8 and the battery container 1, the insulating tape 12 is wound on the battery lid side of the electrode group 8. However, the outer diameter of the positive electrode current collecting component 5 is large, and the outer peripheral surface of the cylindrical portion 5 a is located near the outer peripheral surface of the electrode group 8. For this reason, since the cylindrical portion 5 a is located below the constricted portion of the battery case 1, the insulating tape 12 is arranged between the positive electrode current collector component 5 and the battery case 1 while maintaining the same diameter as the electrode group 8. ing. On the other hand, as shown in FIG. 17, when the outer diameter of the positive electrode current collecting component 5 is made smaller than the outer diameter of the electrode group 8, the lower end of the gasket 2 is extended to the electrode group 8 side. Electrical insulation between the poles is maintained. However, in these cylindrical lithium ion secondary batteries, the space formed between the battery lid and the positive electrode current collecting component 5 becomes large, and therefore the electrode group 8 with respect to the height (length) of the battery container 1. Is limited to a small height, which is a cause of lowering volume energy density, especially volumetric power density.

  From this point of view, when the distance between the battery lid and the positive electrode current collector component 5 is reduced, the protruding end of the constricted portion of the battery container 1 faces the outer peripheral surface of the positive electrode current collector component 5 as shown in FIG. Will be located. In this case, the insulating tape 12 is disposed so as to cover the leading end side of the positive electrode tab 9 c from the end of the electrode group 8. However, as shown in FIG. 15, since the position of the insulating tape 12 is not determined, the positive electrode tab 9c (particularly, the positive electrode tab located on the outermost periphery) is cut by an unexpected external force such as vibration or impact. There is a possibility that the cut positive electrode tab 9c may come into contact with the battery container 1 having a different polarity. Moreover, when the lower end part of the gasket 2 is extended to the electrode group 8 side, the gasket 2 may come into contact with the positive electrode tab 9c and be cut. Accordingly, not only the battery performance but also the battery reliability is impaired. The present embodiment is a cylindrical lithium ion secondary battery that can solve these problems.

  In this embodiment, the insulating tape 12 is wound around so as to cover the periphery of the positive electrode tab 9 c from the end of the electrode group 8. The insulating tape 12 is located between the protruding end of the constricted portion of the battery case 1 and the upper lid case 4 with respect to the upper surface position 5d of the cylindrical portion 5a of the positive electrode current collector component 5 at the end position on the upper lid case 4 side. Have been adjusted so that. For this reason, even if the positive electrode tab 9c, especially the outermost peripheral positive electrode tab 9d is cut by an unexpected external force due to vibration or impact, the insulating tape 12 makes contact with the cut positive electrode tab 9c with the battery container 1 serving also as the negative electrode external terminal. Hindered (see Example 1). Further, even if the outermost peripheral positive electrode tab 9d is connected in a bulging state, contact with the battery container 1 is hindered (see Example 2). Therefore, electrical insulation between the positive electrode tab 9c and the battery container 1 can be ensured, and battery reliability can be improved.

  Moreover, in this embodiment, only the part located in the outer periphery of the electrode group 8 of the insulating tape 12 is adhere | attached on the separator. For this reason, even if an unexpected external force acts, the insulating tape 12 does not move, but is held between the battery container 1 and the positive electrode tab 9c or the positive electrode current collector component 5. Thereby, the electrical insulation between different poles is securable. In addition, the insulating tape 12 is arranged without being bonded on the battery lid side from the one end face of the electrode group 8. For this reason, since damage to the insulating tape 12 itself due to vibration, impact, or the like is suppressed, a function of ensuring insulation can be achieved.

  Furthermore, in the present embodiment, the end position of the insulating tape 12 is determined based on the upper surface position 5 d on the battery lid side in the cylindrical portion 5 a of the positive electrode current collector component 5. Therefore, when the insulating tape 12 is rubbed against the electrode group 8, the end position on the battery lid side can be easily adjusted, and the position between the protruding end portion of the constricted portion of the battery container 1 and the upper lid case 4 can be adjusted. Can be made. The insulating tape 12 is wound so that the end on the battery lid side has a diameter smaller than the outer diameter of the electrode group 8. For this reason, even if the protruding end portion of the constricted portion of the battery container 1 is positioned so as to face the outer peripheral surface of the cylindrical portion 5a of the positive electrode current collector component 5, the end of the insulating tape 12 is positioned closer to the battery lid than the constricted portion. Can be made. Further, the end of the insulating tape 12 on the battery lid side is adjusted to a position that is not in contact with the lower surface of the battery lid (upper lid case 4). For this reason, since the opening is formed at the end of the insulating tape 12, for example, even if the battery internal pressure rises at the time of gas generation such as when the battery is abnormal, the discharge valve formed in the upper lid case 4 is reliably operated. be able to.

  Furthermore, in this embodiment, the positive electrode current collector component 5 and the negative electrode current collector component 6 are each formed in a disc shape having a cylindrical portion 5a and a cylindrical portion 6a, and a plurality of outer peripheral surfaces of the cylindrical portions 5a and 6a are respectively provided. The positive electrode tab 9c and the negative electrode tab 10c are joined. For this reason, a conductive path can be ensured even if a part of the positive and negative electrode tabs is cut. Further, since the area of the conductive path is ensured by joining the plurality of positive and negative electrode tabs, the internal resistance can be reduced.

  In the present embodiment, the battery container 1 serves as the negative electrode external terminal, and the battery cover serves as the positive electrode external terminal. However, the present invention is not limited to this, and the battery container 1 includes the positive electrode external terminal, The battery lid can also serve as the negative electrode external terminal. In this case, the insulating tape on the inner bottom side of the battery container 1 may be determined based on the surface position of the cylindrical portion of the current collecting component as described above.

  In the present embodiment, an example in which the insulating tape 12 is wound around the battery lid and the insulating tape 13 is wound around the inner bottom of the container around the electrode group 8 is shown, but the present invention is not limited to this. . As described above, when the battery lid also serves as the positive electrode external terminal and the battery container 1 also serves as the negative electrode external terminal, it is only necessary to provide an insulating tape on at least the battery lid side. Of course, an insulating tape may be arranged over the entire outer peripheral surface of the electrode group. In the present embodiment, an insulating tape made of polyimide or the like has been exemplified, but the present invention is not limited to this, and any material film having electrical insulation may be used. Of course, the width and thickness of the film, tape, etc. are not limited.

  Furthermore, in this embodiment, although the example which accommodates the electrode group 8 in the cylindrical battery container 1 was shown, this invention is not restrict | limited to this. For example, the positive and negative electrode plates can be wound in a flat shape and accommodated in a flat battery container. In this case, the cross-sectional shape of the battery container can be an ellipse or an ellipse. Even in such a battery container, the battery lid can be caulked and fixed by constricting the opening side.

  Furthermore, in the present embodiment, the example in which the insulating tape 12 is wound and disposed on the battery lid side is shown, but the present invention is not limited to this. For example, you may make it cover the member which shape | molded the film in the funnel shape so that it may reduce in diameter toward the battery cover side from the edge part of the electrode group 8. FIG. In this way, the insulating member can be easily arranged at the time of battery assembly, and since the opening on the battery lid side is formed uniformly by forming it in a funnel shape, gas is discharged when the battery internal pressure rises abnormally. A route can be secured. Further, the insulating tape 12 is wound in a cylindrical shape having the same diameter as the outer diameter of the electrode group 8 and the electrode group 8 is accommodated in the battery container 1. You may make it the diameter of an edge part shrink.

  Furthermore, in the present embodiment, the lithium ion secondary battery is exemplified, but the present invention is not limited to this, and can be applied to a sealed battery in which a battery lid is caulked and fixed to a bottomed battery container. it can. Moreover, it does not restrict | limit to the component of a positive electrode active material, a negative electrode active material, a nonaqueous electrolyte solution, etc., It cannot be overemphasized that the component normally used for a lithium ion secondary battery may be used.

  Since the present invention provides a sealed battery that can ensure electrical insulation between different poles and improve battery reliability, it contributes to the manufacture and sale of sealed batteries. Have potential.

1 Battery container (bottomed container)
2 Gasket 3 Upper lid (part of lid)
4 Upper lid case (part of lid)
5 Positive Current Collector 6 Negative Current Collector 8 Electrode Group 9 Positive Plate (Positive)
9c Positive electrode tab 10 Negative electrode plate (negative electrode)
10c Negative electrode tab 12 Insulation tape (electrical insulation film)
13 Insulation tape (electrical insulation film)
20 Cylindrical lithium ion secondary battery (sealed battery)

Claims (3)

An electrode group in which positive and negative electrodes are wound through a separator;
The electrode group is housed, a constricted portion protruding in the center direction is formed on the opening side, and a bottomed container that also serves as one of the positive and negative electrodes,
A lid that is caulked and fixed to the opening side from the constricted portion of the container via an electrically insulating gasket, and also serves as the other terminal of the positive and negative electrodes,
A current collector component disposed opposite to the end face on the lid side of the electrode group, wherein the tip portions of a plurality of tabs led out from the other of the positive and negative electrodes are joined to the outer peripheral surface;
With
The current collecting component has a diameter smaller than the diameter of the electrode group, and is arranged so that the outer peripheral surface is located on the center side from the constricted portion of the container,
An electrical insulating film is arranged on the outer periphery of the electrode group on the lid side so as to cover the periphery of the plurality of tabs joined to the outer peripheral surface of the current collector component, and the end of the film on the lid side Located on the lid side beyond the constricted portion of the container,
The film is arranged such that only the portion located on the outer periphery of the electrode group is fixed to the electrode group, and the end on the lid side is arranged to have a diameter smaller than the diameter of the electrode group. A sealed battery.   2. The sealed battery according to claim 1, wherein an end of the lid side of the film is defined at a position that is not in contact with a surface of the lid on the electrode group side.   The sealed battery according to claim 1, wherein the container also serves as a terminal for the negative electrode, and the lid also serves as a terminal for the positive electrode.

Images