JP2016119156A - Power storage element and power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize a power storage element which has a case body and a lid welded by a laser while stably securing high joining strength between the case body and lid and thereby to minimize a power storage device which modularizes a plurality of power storage elements.SOLUTION: A power storage element 1 comprises: a case body 3 which has a wall part 32 whose tip constitute a peripheral edge of an opening 3a and houses an electrode body 10 inside; and a lid 4 which closes the opening 3a of the case body 3. The lid 4 comprises: a lid body 64 which covers the tip of the wall part 32 of the case body 3; and an engagement part 65 which is positioned inside the lid body 64 in a thickness direction of the lid body, and engages the wall part 32. A weld zone 70 is formed from an outer surface of the lid body 64 to a boundary surface between the lid 4 and wall part 32 to be positioned inside an outer surface 52 of the wall part 32.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a power storage element including a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, and a power storage device in which a plurality of power storage elements are modularized.

  In general, a power storage element including a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery includes an exterior body that houses an electrode body. The exterior body may be composed of a metal case body and a metal lid that closes the opening of the case body. In this type of power storage element, the lid may be welded to the periphery of the opening by laser irradiation in a state where the opening of the case body is closed.

  Patent Document 1 discloses an example of a power storage element in which a peripheral edge portion of a lid is laser welded to an upper end portion of a case body. In the electric storage element of Patent Document 1, a stepped cutout is formed in the lower surface peripheral portion of the lid, so that the peripheral portion of the lid is a thin portion. The thin portion is fillet welded to the upper end portion of the case body by being irradiated with laser from above while being partially placed on the upper end surface of the case body. According to the electric storage element of Patent Document 1, the upper end of the case main body is engaged with the notch on the lower surface of the lid during welding, thereby preventing the position shift and dropout of the lid.

JP 2011-181215 A

  However, when the end portion of the lid is joined to the upper end portion of the case body by fillet welding as in the power storage element of Patent Document 1, if the amount of material penetration is increased, the melted material moves outward in the width direction of the case body. By dripping and solidifying, a bead is formed so as to protrude from the side surface of the case main body, and there is a problem that the size of the storage element increases by the amount of protrusion of the bead. In particular, in a power storage device in which a plurality of power storage elements are overlapped to form a module, a bead is interposed between adjacent power storage elements, so that an interval between the power storage elements is widened, which prevents downsizing of the power storage device.

  Therefore, an object of the present invention is to minimize the power storage element in which the lid is laser welded to the case body, and thus to minimize the power storage device in which a plurality of power storage elements are modularized.

  The present invention includes a case main body including a wall portion whose tip constitutes the periphery of the opening, and an electrode body accommodated therein, and a lid that closes the opening of the case main body, the lid of the case main body A lid main body that covers the tip of the wall portion; and an engaging portion that is positioned on the inner side in the thickness direction of the lid main body with respect to the lid main body and engages with the wall portion, and the lid from the outer surface of the lid main body A storage element is provided in which a welded portion is formed so as to be located on an inner side of an outer surface of the wall portion over an interface between the wall portion and the wall portion.

  The welded part is formed from the outer surface of the lid body that covers the tip of the wall part of the case body to the interface between the lid and the wall part, so that the melted material is in the wall thickness direction while ensuring a sufficient amount of penetration during welding. The drooping to the outside is suppressed. Thereby, it is prevented that a bead protruding from the outer surface of the wall portion is formed, and the size of the case body can be minimized.

  In addition, the present invention provides a power storage device including a plurality of the above power storage elements, wherein the plurality of power storage elements are overlapped in the thickness direction of the wall portion.

  Since each power storage element constituting the power storage device prevents the bead from protruding from the outer surface of the wall as described above, a plurality of power storage elements are overlapped so that the interval between adjacent power storage elements is minimized. be able to. This minimizes the power storage device.

  ADVANTAGE OF THE INVENTION According to this invention, the increase in size by the protrusion of a bead to the circumference | surroundings of a case main body can be prevented in the electrical storage element by which a lid | cover is welded to a case main body, and the electrical storage apparatus with which the said multiple electrical storage elements were piled up.

1 is a perspective view of a nonaqueous electrolyte secondary battery according to a first embodiment of the present invention. The longitudinal cross-sectional view of the nonaqueous electrolyte secondary battery of FIG. The side view of the assembled battery provided with two or more nonaqueous electrolyte secondary batteries of FIG. The side view of the modification of an assembled battery. The VV sectional view taken on the line of FIG. The enlarged view of the part VI of FIG. The perspective view which looked at the lid | cover from the inner surface side. The perspective view of the lid concerning a modification. Sectional drawing similar to FIG. 5 of the nonaqueous electrolyte secondary battery which concerns on 2nd Embodiment. The enlarged view of the part X of FIG. Sectional drawing similar to FIG. 5 of the nonaqueous electrolyte secondary battery which concerns on 3rd Embodiment. The enlarged view of the part XII of FIG. The longitudinal cross-sectional view of a part of the battery outer body according to the first comparative example. The enlarged view of the part XIV of FIG. The longitudinal cross-sectional view of a part of the battery outer body according to the second comparative example. The enlarged view of the part XVI of FIG.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. In the following description, terms indicating specific directions and positions (for example, terms including “up”, “down”, “side”, “end”) are used as necessary. Is for facilitating understanding of the invention with reference to the drawings, and the technical scope of the present invention is not limited by the meaning of these terms. Further, the following description is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

[First Embodiment]
1 and 2 show a lithium ion secondary battery (hereinafter simply referred to as “battery”) 1 according to a first embodiment of the present invention.

  As shown in FIGS. 1 and 2, the battery 1 includes a substantially rectangular parallelepiped exterior body 2, for example. The exterior body 2 contains an electrode body 10 and an electrolytic solution (not shown). The exterior body 2 includes a case body 3 having an opening 3 a at the upper end and a lid 4 that closes the opening 3 a of the case body 3.

  The case body 3 includes a rectangular plate-shaped bottom wall portion 31, a pair of long side wall portions 32 rising from the long side of the bottom wall portion 31, and a pair of short side wall portions 33 rising from the short side of the bottom wall portion 31. The upper ends of the pair of long side wall portions 32 and the pair of short side wall portions 33 define an opening 3 a of the case body 3. The lid 4 has a generally rectangular plate shape. The lid 4 is provided with a safety valve 8 for discharging the gas in the exterior body 2 and a liquid stopper 9 for closing the liquid injection port.

  The case main body 3 and the lid 4 constituting the exterior body 2 are made of metal such as aluminum or aluminum alloy. However, the material of the case body 3 and the lid 4 is not particularly limited as long as it is a metal, and may be different from each other. A more specific configuration of the exterior body 2 will be described later.

  As shown in FIG. 2, the lid 4 includes negative and positive external terminals 14 and 15, and negative and positive current collectors 20 and 21 that electrically connect the electrode body 10 and the external terminals 14 and 15. It is fixed.

  The negative external terminal 14 is disposed on one end side (left side in FIG. 2) of the lid 4, and the positive external terminal 15 is disposed on the other end side (right side in FIG. 2) of the lid 4. The negative external terminal 14 is caulked and fixed to the upper surface of the lid 4 via the upper packing 16 by, for example, a rivet (not shown) separate from the negative external terminal 14. The positive external terminal 15 is caulked and fixed to the upper surface of the lid 4 via the upper packing 16 by, for example, a rivet portion integrated with the positive external terminal 15.

  The electrode body 10 is a wound body in which a positive electrode sheet, a negative electrode sheet, and a separator interposed between the two electrode sheets are overlapped and wound in an elliptical shape around a winding axis. . A negative electrode lead portion 11d electrically connected to the negative electrode sheet is provided at one end (the left end in FIG. 2) of the electrode body 10 in the direction in which the winding axis extends, and the positive electrode sheet is provided at the other end. An electrically conductive positive electrode lead portion 12d is provided.

  Each of the negative electrode and positive electrode current collectors 20 and 21 has base portions 20a and 21a fixed to the lower surface of the lid 4, and a pair of leg portions 20b and 21b extending downward from the base portions 20a and 21a. The base portion 20 a of the negative electrode current collector 20 is crimped and fixed to the lower surface of the lid 4 via the lower packing 18 by, for example, the above-described rivets so as to be electrically connected to the negative electrode external terminal 14. The base portion 21 a of the positive electrode current collector 21 is crimped and fixed to the lower surface of the lid 4 via the lower packing 18 by, for example, the above-described rivet portion so as to be electrically connected to the positive electrode external terminal 15.

  The leg portion 20 b of the negative electrode current collector 20 is electrically and mechanically connected to the negative electrode lead portion 11 d of the electrode body 10. Specifically, for example, the negative electrode lead portion 11d of the electrode body 10 is sandwiched between the pair of leg portions 20b of the negative electrode current collector 20, and the pair of leg portions 20b is sandwiched between the C-shaped clips 26. By performing ultrasonic welding, the leg portion 20b of the negative electrode current collector 20 and the negative electrode lead portion 11d of the electrode body 10 are connected.

  Similarly, the leg portion 21 b of the positive electrode current collector 21 is electrically and mechanically connected to the positive electrode lead portion 12 d of the electrode body 10. Specifically, for example, the positive electrode lead portion 12 d of the electrode body 10 is sandwiched between the pair of leg portions 21 b of the positive electrode current collector 21, and the pair of leg portions 21 b is sandwiched between the C-shaped clips 26. By performing ultrasonic welding, the leg portion 21b of the positive electrode current collector 21 and the positive electrode lead portion 12d of the electrode body 10 are joined.

  In the present embodiment, the negative electrode external terminal 14 is made of aluminum or an aluminum alloy, the rivet for fixing the negative electrode external terminal 14 and the negative electrode current collector 20 to the lid 4, and the negative electrode current collector 20 is copper or a copper alloy. It is made. The positive external terminal 15 and the positive electrode current collector 21 are made of aluminum or an aluminum alloy.

  As described above, the negative electrode and positive electrode current collectors 20 and 21 are fixed to the lid 4, and the electrode body 10 is joined to the negative electrode and positive electrode current collectors 20 and 21. It is suspended and supported by the lid 4 via the electric body 20 and the positive electrode current collector 21.

  In addition, the whole structure of the battery 1 demonstrated above is only an example, and the structure of the battery 1 other than the structure of the exterior body 2 mentioned later can be changed arbitrarily.

[Configuration of assembled battery]
FIG. 3 is a side view schematically showing an assembled battery 80 including a plurality of the batteries 1 described above. As shown in FIG. 3, the assembled battery 80 is a power storage device in which a plurality of the above batteries 1 are stacked in a predetermined stacking direction X to be modularized. The stacking direction X is a direction parallel to the wall thickness direction of the long side wall portion 32 (see FIG. 1) of the case body 3.

  Among the plurality of batteries 1 stacked as described above, for example, a resin end plate 82 is stacked on the outer side of the battery 1 disposed on the outermost side on both sides in the stacking direction X. The stacked body composed of the plurality of batteries 1 and the pair of end plates 82 stacked in this way is sandwiched from both sides in the stacking direction X by both ends of a plurality of restraining bands 84 made of metal, for example. Both ends of each restraint band 84 are fixed to the end plate 82 by bolts, for example. Thereby, the plurality of batteries 1 are held in a stacked state. The external terminals 14 and 15 of the plurality of batteries 1 are electrically connected via a connection member such as a bus bar 86.

  However, the configuration of the assembled battery 80 illustrated in FIG. 3 is merely an example, and various modifications can be made to the configuration of the assembled battery. For example, in the assembled battery 30 shown in FIG. 3, the long side wall portions 32 of the adjacent batteries 1 are overlapped, but the short side wall portions 33 of the adjacent batteries 1 may be overlapped.

  FIG. 4 is a side view schematically showing the assembled battery 90 according to the modification. In the assembled battery 90 shown in FIG. 4, a plurality of batteries 1 are stacked such that a spacer 98 is interposed between adjacent batteries 1. The other configuration of the assembled battery 90 is the same as that of the assembled battery 80 shown in FIG. 3, and the plurality of batteries 1 constituting the assembled battery 90 are stacked using the end plate 82 and the restraining band 84 via the spacer 98. Held in a state.

  According to the assembled battery 90 shown in FIG. 4, the spacers 98 interposed between the adjacent batteries 1 can reliably achieve insulation between the batteries 1 and can position the plurality of batteries 1 relative to each other.

[Exterior body]
Hereinafter, a more specific configuration of the outer package 2 of the battery 1 will be described.

  As shown in FIGS. 1 and 2, the lid 4 is welded to the peripheral portion of the opening 3 a in the case body 3, that is, the upper end portion of the long side wall portion 32 and the upper end portion of the short side wall portion 33. The joint portion between the long side wall portion 32 and the lid 4 and the joint portion between the short side wall portion 33 and the lid 4 have the same joint structure.

  With reference to FIGS. 5 to 7, the structure of the joint portion between the case body 3 and the lid 4 and the peripheral portion thereof will be described. 5 is a cross-sectional view showing a part of the battery 1 in the VV line cross section of FIG. 1, FIG. 6 is an enlarged view of a part VI of FIG. 5, and FIG. It is the perspective view seen from the side.

  In the following, the joint between the long side wall 32 and the lid 4 of the case main body 3 illustrated in FIGS. 5 and 6 will be described, and the joint between the short side wall 33 and the lid 4 will not be illustrated or described. To do. In the following description, the long side wall portion 32 is also simply referred to as “wall portion 32”.

  As shown in FIG. 5, each wall portion 32 includes an inner surface 51 that faces the electrode body 10 accommodated in the exterior body 2, and an outer surface 52 that is located on the opposite side of the inner surface 51. The inner surface 51 and the outer surface 52 of the wall portion 32 are disposed substantially parallel to the thickness direction of the lid 4. The wall portion 32 includes an upper surface 53 that straddles the upper end of the inner surface 51 and the upper end of the outer surface 52. The upper surface 53 is a part constituting the periphery of the opening 3a (see FIG. 2) of the case body 3. The upper surface 53 is adjacent to the inner surface 51 and the outer surface 52 through corners at substantially right angles, and is disposed substantially parallel to the thickness direction of the wall portion 32.

  As shown in FIGS. 5 to 7, the lid 4 includes an inner surface 61 that faces the electrode body 10 accommodated in the exterior body 2, and an outer surface 62 that is located on the opposite side of the inner surface 61. The inner surface 61 and the outer surface 62 of the lid 4 are disposed substantially parallel to the thickness direction of the wall portion 32. A cutout portion 63 having an L-shaped cross section, for example, is provided at a corner portion on the inner surface 61 side in the peripheral edge portion of the lid 4.

  The lid 4 includes a lid main body 64 that is an upper portion of the notch 63 in the lid 4 and an inner fitting portion 65 that is located on the inner side in the wall thickness direction of the notch 63 in the lid 4. The lid body 64 includes a substantially rectangular peripheral edge portion 64a. The inner fitting portion 65 is provided so as to protrude downward from a portion surrounded by the peripheral edge portion 64 a of the lid main body 64.

  The lid 4 has a posture in which the inner fitting portion 65 is positioned on the inner side in the lid thickness direction than the lid body 64, and the case body 3 has a peripheral portion 64 a supported by the upper surface 53 of the wall portion 32. It is attached to the upper end. Thereby, the inner fitting part 65 is arrange | positioned so that it may fit inside the case main body 3. FIG.

  As shown in FIG. 6, the lower surface 66 of the peripheral edge portion 64 a of the lid body 64 is configured by a surface substantially parallel to the inner surface 61 and the outer surface 62 of the lid 4, and is disposed substantially parallel to the thickness direction of the wall portion 32. ing. The peripheral edge portion 64 a of the lid body 64 covers the entire upper surface 53 of the wall portion 32. As a result, the lower surface 66 of the peripheral edge portion 64 a is supported by the wall portion 32 in a state of being in contact with the substantially entire surface of the upper surface 53 of the wall portion 32.

  The peripheral edge portion 64 a of the lid 4 is supported over the entire circumference by the upper surfaces of the pair of long side wall portions 32 and the pair of short side wall portions 33. Thereby, when the lid 4 is welded to the case body 3, the entire peripheral edge portion 64 a of the lid 4 can be temporarily placed on the upper surface 53 of the wall portion 32.

  The inner fitting portion 65 is engaged with the inner surface 51 of the wall portion 32 in a state of protruding into the case main body 3 from the opening 3a (see FIG. 2). The outer peripheral surface 68 of the inner fitting portion 65 is configured by a surface substantially parallel to the lid thickness direction, and is disposed substantially parallel to the inner surface 51 of the wall portion 32. Thereby, the inner fitting part 65 is engaged with the wall part 32 so that the outer peripheral surface 68 and the inner surface 51 of the wall part 32 face each other in a substantially parallel state. By engaging the wall portion 32 of the case body 3 and the inner fitting portion 65 of the lid 4, the lid 4 can be positioned with respect to the case body 3, whereby the lid 4 is dropped into the case body 3. Can be prevented.

  The outer peripheral surface 67 of the lid main body 64 is configured by a surface substantially parallel to the thickness direction of the lid 4, and is arranged so as to be continuous with the outer surface 52 of the wall portion 32. That is, the lid 4 is disposed so as not to protrude outward from the outer surface 52 of the wall portion 32 in the wall thickness direction.

  As described above, since various components such as the external terminals 14 and 15, the current collectors 20 and 21, and the electrode body 10 are assembled to the lid 4, the lid 4 is required to have higher rigidity than the case body 3. Is done. In order to meet this requirement, the thickness D2 of the thick portion of the lid 4, that is, the portion where the inner fitting portion 65 is provided is larger than the thickness D1 of the wall portion 32 of the case body 3. For example, the thickness D1 of the wall part 32 is 0.5 mm or more and less than 1.0 mm, and the thickness D2 of the lid 4 is 1.0 mm or more and less than 2.0 mm.

  The lid 4 is welded to the upper end portion of the wall portion 32 of the case body 3 by laser irradiation from the outside in the thickness direction. Specifically, laser is irradiated from above toward the outer surface 62 of the lid body 64 along a direction parallel to the thickness direction of the lid 4, so that the welded portion 70 extends in the thickness direction of the lid 4. It is formed. The welded portion 70 is formed so as to be located on the inner side of the outer surface 52 of the wall portion 32 from the outer surface 62 of the lid main body 64 to the interface between the lid 4 and the wall portion 32.

  It is preferable that the welding part 70 is formed so that the interface of the outer peripheral surface 68 of the inner fitting part 65 of the cover 4 and the inner surface 51 of the wall part 32 which are arrange | positioned substantially parallel to the cover thickness direction may be included. In this case, the area of the interface between the lid 4 and the wall portion 32 included in the welded portion 70 can be increased, and thereby the bonding strength between the lid 4 and the wall portion 32 can be increased.

  With the configuration of the exterior body 2 described above, the battery and the assembled battery according to the first embodiment exhibit various functions and effects. Hereinafter, the operational effects of the first embodiment will be described in comparison with the battery 801 according to the first comparative example shown in FIGS. 13 and 14 and the battery 901 according to the second comparative example shown in FIGS. 15 and 16. .

  FIG. 13 is a longitudinal sectional view similar to FIG. 5 showing a part of the exterior body 802 of the battery 801 according to the first comparative example, and FIG. 14 is an enlarged view of the partial XIV shown in FIG.

  As shown in FIG. 13, also in the battery 801 according to the first comparative example, the exterior body 802 includes a case main body 803 and a lid 804. The wall portion 830 of the case main body 803 includes a wall main body 840 and a protruding portion 843 that protrudes upward from the upper end of the wall main body 840. A support surface portion 842 that supports the end portion of the lid 804 is formed at the upper end of the wall portion main body 840.

  As shown in FIG. 14, in the battery 801 according to the first comparative example, the outer surface 805 of the lid 804 protrudes from above to form a welded portion 870 including the interface between the lid 804 and the protruding portion 843 of the wall portion 830. When laser irradiation is performed toward the boundary portion with the upper surface 844 of the portion 843, a gap or a minute step is generated in the boundary portion, so that it becomes difficult to stabilize the focal length of the laser irradiation. The penetration depth tends to be unstable. Therefore, at the time of welding, a laser enters the case main body 803 or a melted material hangs outward in the wall thickness direction, thereby forming a bead 872 that protrudes outward in the wall thickness direction from the outer surface 852 of the wall portion 830. It becomes easy. When such a bead 872 is formed, the size of the case main body 803 and consequently the size of the battery 801 are increased by the amount of protrusion R of the bead 872 in the wall thickness direction.

  Further, when assembling the assembled battery as shown in FIG. 3 by stacking a plurality of the batteries 801 according to the first comparative example, the beads 872 are interposed between the adjacent batteries 801 and between the battery 801 and the end plate 82. As a result, the dimension L1 of the assembled battery increases in the stacking direction X.

  Similarly, when an assembled battery as shown in FIG. 4 is assembled by stacking a plurality of batteries 801 according to the first comparative example, beads are placed between the battery 801 and the spacer 98 and between the battery 801 and the end plate 82. By interposing 872, the dimension L2 of the assembled battery increases in the stacking direction X.

  Further, in the first comparative example, it is conceivable to suppress the increase in the size of the assembled battery by making the shapes of the spacer 98 and the end plate 82 such that interference with the beads 872 is avoided. In this case, special processing of the spacer 98 and the end plate 82 is required.

  On the other hand, in the first embodiment, the laser beam is irradiated toward the outer surface 62 of the flat lid 4 at the time of welding, so that the melted material droops outward in the wall thickness direction while ensuring a sufficient amount of penetration. It is suppressed. As a result, the formation of a bead that protrudes from the outer surface 52 of the wall portion 32 is prevented, and the dimension of the case main body 3 and thus the dimension of the battery 1 can be minimized in the wall thickness direction.

  Further, there is an advantage that the focal length can be easily stabilized by irradiating the laser toward the outer surface 62 of the flat lid 4. When the distance from the outer surface 62 of the lid 4 in the thickness direction of the lid 4 to the deepest part of the welded portion 70 is defined as the penetration depth D3 of the welded portion 70, the focal length of laser irradiation is stabilized as described above, The penetration depth D3 of the welded portion 70 is also stable, and thus high joint strength can be obtained stably.

  Furthermore, since the penetration depth D3 of the welded portion 70 is stabilized, there is an advantage that laser penetration into the case main body 3 is suppressed during welding, thereby preventing degradation of the performance of the electrode body 10 due to laser irradiation. can do.

  Further, according to the first embodiment, in each battery 1, the lid 4 and the bead are prevented from protruding from the outer surface 52 of the wall portion 32, so that the assembled battery 80, as shown in FIG. 3 or 4, When assembling 90, the spacing between adjacent batteries 1, between batteries 1 and end plate 82, and between battery 1 and spacer 98 can be minimized. As a result, the assembled batteries 80 and 90 are minimized in the stacking direction X.

  Further, according to the first embodiment, the formation of the bead 872 as in the first comparative example is prevented, so that special processing for avoiding interference with the bead 872 in the manufacture of the assembled batteries 80 and 90 is performed. Need not be applied to the end plate 82 and the spacer 98.

  In the first embodiment, since the lid 4 covers the entire upper surface 53 of the wall portion 32, the width of the portion that supports the lid 4 in the wall portion 32 is increased compared to the first comparative example. It is possible to reliably prevent the lid 4 temporarily placed on the upper surface 53 of the wall portion 32 from falling off. Furthermore, according to the first embodiment, since it is not necessary to perform special processing for engagement with the lid 4 on the upper end portion of the wall portion 32, ready-made products can be used as the case body 3, or the case body 3 is easy to manufacture.

  FIG. 15 is a longitudinal sectional view similar to FIG. 5 showing a part of the exterior body 902 of the battery 901 according to the second comparative example, and FIG. 16 is an enlarged view of a portion XVI shown in FIG.

  As shown in FIG. 15, also in the battery 901 according to the second comparative example, the exterior body 902 includes a case main body 903 and a lid 904. In the battery 901 according to the second comparative example, the lid 904 includes a lid body 906 having a peripheral edge portion 906a that covers the upper surface 952 of the wall portion 940 of the case body 903, and an inner surface 951 of the wall portion 940 that protrudes downward from the lid body 906. And an inner fitting portion 907 that engages with.

  As shown in FIG. 16, also in the battery 901 according to the second comparative example, the thickness S1 of the wall portion 940 is smaller than the thickness S2 of the lid 904, as in the first embodiment. Further, unlike the first embodiment, welding of the lid 904 and the wall portion 940 is performed by laser irradiation from the side. Thereby, a welded portion 970 including an interface between the peripheral edge portion 906a of the lid 904 and the upper surface 952 of the wall portion 940 is formed. The penetration depth S3 of the welded portion 970 formed in this manner is at most the same as the thickness S1 of the wall portion 940, and it is difficult to form the welded portion 970 deeper than the wall thickness S1.

  On the other hand, as shown in FIGS. 5 and 6, in the first embodiment, laser irradiation is performed along the thickness direction of the lid 4, which is thicker than the wall portion 32. It is easy to ensure a large depth D3. Thereby, the penetration depth D3 is larger than the thickness D1 of the wall portion 32. For this reason, the bonding strength between the case body 3 and the lid 4 can be increased.

  In the first embodiment, the example in which the notch 63 of the lid 4 has an L-shaped cross section and the lower surface 66 of the peripheral edge 64a of the lid 4 is disposed substantially parallel to the wall thickness direction has been described. The shape of the lower surface 66 of the peripheral edge portion 64 a can be changed as appropriate according to the shape of the upper surface 53 of the wall portion 32.

  Further, in the first embodiment, as illustrated in FIG. 7, the example in which the inner fitting portion 65 of the lid 4 is a rectangular plate shape has been described. However, like the lid 104 according to the modification illustrated in FIG. Instead of the inner fitting portion 65 having a rectangular shape, a rectangular frame-like inner fitting portion 165 may be provided. In this case, the same effect can be obtained.

[Second Embodiment]
The configuration of the exterior body 202 of the battery 201 according to the second embodiment, in particular, the configuration of the joint portion between the case main body 203 and the lid 204 that configures the exterior body 202 will be described with reference to FIGS. 9 and 10.

  In the second embodiment, the configuration of the battery 201 other than the exterior body 202 is the same as that of the battery 1 according to the first embodiment. In the description of the second embodiment, the same components as those of the first embodiment are not described, and the same reference numerals as those of the first embodiment are given in FIGS. 9 and 10.

  Further, in the description of the second embodiment, the joint portion between the long side wall portion 232 and the lid 204 of the case main body 203 illustrated in FIGS. 9 and 10 will be described, and the joint portion between the short side wall portion and the lid 204 will be described. Illustration and description are omitted. In the following description, the long side wall portion 232 is also simply referred to as “wall portion 232”.

  As shown in FIG. 9, each wall portion 232 includes an inner surface 251 facing the electrode body 10 accommodated in the exterior body 202, and an outer surface 252 located on the opposite side of the inner surface 251. The inner surface 251 and the outer surface 252 of the wall portion 232 are disposed substantially parallel to the thickness direction of the lid 204. On the inner surface 251 at the upper end of the wall 232, for example, a notch 241 having an L-shaped cross section is formed.

  The wall portion 232 includes a wall portion main body 240 including a lower portion than the notch portion 241 in the wall portion 232. The inner portion in the wall thickness direction at the upper end of the wall portion main body 240 is a support surface portion 242 that supports the lid 204. The support surface portion 242 is configured by a surface substantially parallel to the wall thickness direction.

  The wall portion 232 includes a protruding portion 243 located on the outer side in the wall thickness direction than the notch portion 241 in the wall portion 232. The protrusion 243 has a wall thickness smaller than that of the wall main body 240 and is provided so as to protrude upward from the upper end of the wall main body 240. The upper end of the protrusion 243 constitutes the periphery of the opening of the case body 203.

  As shown in FIG. 10, the protruding portion 243 includes an inner surface 253 that is located on the outer side of the inner surface 251 of the wall main body 240. The inner surface 253 of the projecting portion 243 is adjacent to the support surface portion 242 via a substantially right-angled corner, and is disposed substantially parallel to the thickness direction of the lid 204. Moreover, the protrusion part 243 is provided with the upper surface 254 which adjoins the inner surface 253 and the outer surface 252 through a substantially right-angled corner, respectively. The upper surface 254 of the protrusion 243 is disposed substantially parallel to the wall thickness direction.

  As shown in FIG. 9, the lid 204 includes an inner surface 261 facing the electrode body 10 accommodated in the exterior body 202, and an outer surface 262 located on the opposite side of the inner surface 261. The inner surface 261 and the outer surface 262 of the lid 204 are disposed substantially parallel to the thickness direction of the wall portion 232. A cutout portion 263 having an L-shaped cross section, for example, is provided at a corner portion on the inner surface 261 side at the peripheral edge portion of the lid 204.

  The lid 204 includes a lid main body 264 that is an upper portion of the notch 263 in the lid 204 and an inner fitting portion 265 that is located on the inner side in the wall thickness direction of the notch 263 in the lid 204. The lid body 264 includes a substantially rectangular peripheral edge 264a. The inner fitting portion 265 is provided so as to protrude downward from a portion surrounded by the peripheral edge portion 264 a in the lid main body 264. In addition, although the inner side fitting part 265 is comprised by the plate-shaped part like the inner side fitting part 65 shown in FIG. 7, even if it is a frame-like part like the inner side fitting part 165 shown in FIG. Good.

  The lid 204 is attached to the upper end portion of the case main body 203 so that the inner fitting portion 265 is positioned on the inner side of the lid main body 264 in the lid thickness direction. Thereby, the inner fitting part 265 is arrange | positioned so that it may fit inside the case main body 203. FIG.

  As shown in FIG. 10, the lower surface 266 of the peripheral edge portion 264a of the lid body 264 is configured by a surface substantially parallel to the inner surface 261 and the outer surface 262 of the lid 204, and is disposed substantially parallel to the wall thickness direction. The lower surface 266 of the peripheral edge portion 264 a of the lid main body 264 is disposed substantially parallel to the upper surface 254 of the protruding portion 243 of the wall portion 232 and covers the entire upper surface 254. The inner surface 261 of the lid 204, that is, the lower surface 261 of the inner fitting portion 265 is disposed substantially parallel to the support surface portion 242 of the wall portion 232 and covers the entire support surface portion 242. The lid 204 is supported by the wall portion 232 in contact with substantially the entire upper surface 254 of the wall portion 232 and substantially the entire support surface portion 242.

  The lid 204 is supported over the entire circumference by the pair of long side wall portions 232 and the pair of short side wall portions. Thereby, when the lid 204 is welded to the case body 203, the entire peripheral edge of the lid 204 can be temporarily placed on the wall portion 232.

  The inner fitting portion 265 of the lid 204 is engaged with the inner surface 253 of the protruding portion 243 of the wall portion 232 in a state of protruding into the case main body 203 from the opening of the case main body 203. The outer peripheral surface 268 of the inner fitting portion 265 is a surface that is substantially parallel to the lid thickness direction, and is disposed substantially parallel to the inner surface 253 of the protruding portion 243 of the wall portion 232. Thereby, the inner fitting part 265 is engaged with the notch part 241 of the wall part 232 so that the outer peripheral surface 268 and the inner surface 253 of the protrusion part 243 face each other in a state of being arranged substantially parallel to each other. . By engaging the notch portion 241 of the wall portion 232 and the inner fitting portion 265 of the lid 204, the lid 204 can be positioned with respect to the case main body 203, whereby the lid 204 is dropped into the case main body 203. Can be prevented.

  The outer peripheral surface 267 of the lid main body 264 is configured by a surface substantially parallel to the thickness direction of the lid 204, and is arranged so as to be continuous with the outer surface 252 of the wall portion 232. That is, the lid 204 is disposed so as not to protrude outward in the wall thickness direction from the outer surface 252 of the wall portion 232.

  The thickness E2 of the thick portion of the lid 204, that is, the portion where the inner fitting portion 265 is provided, is larger than the thick portion of the wall portion 232 of the case main body 203, that is, the thickness E1 of the wall main body 240. For example, the thickness E1 of the wall portion 232 is 0.5 mm or more and less than 1.0 mm, and the thickness E2 of the lid 204 is 1.0 mm or more and less than 2.0 mm.

  The lid 204 is welded to the upper end portion of the wall portion 232 of the case main body 203 by laser irradiation from the outside in the thickness direction. Specifically, laser is irradiated from above toward the outer surface 262 of the lid body 264 along a direction parallel to the thickness direction of the lid 204, so that the welded portion 270 extends in the thickness direction of the lid 204. It is formed. The welded portion 270 is formed so as to be located on the inner side of the outer surface 252 of the wall portion 232 from the outer surface 262 of the lid main body 264 to the interface between the lid 204 and the wall portion 232.

  The welded portion 270 may be formed so as to include an interface between the outer peripheral surface 268 of the inner fitting portion 265 of the lid 204 and the inner surface 253 of the protruding portion 243 of the wall portion 232 that are disposed substantially parallel to the lid thickness direction. preferable. In this case, the area of the interface between the lid 204 and the wall portion 232 included in the welded portion 270 can be increased, and thereby the bonding strength between the lid 204 and the wall portion 232 can be increased.

  With the configuration of the exterior body 202 described above, the battery and the assembled battery according to the second embodiment exhibit various functions and effects. Hereinafter, the effects of the second embodiment are compared with the battery 801 according to the first comparative example (see FIGS. 13 and 14) and the battery 901 according to the second comparative example (see FIGS. 15 and 16). While explaining.

  In the second embodiment, in contrast to the first comparative example in which laser is irradiated toward the boundary portion between the lid 804 and the protruding portion 843 of the wall portion 830 at the time of welding, toward the outer surface 262 of the flat lid 204. Since the laser is irradiated, it is possible to prevent the molten material from drooping outward in the wall thickness direction while securing a sufficient amount of penetration. This prevents the formation of a bead that protrudes from the outer surface 252 of the wall portion 232, thereby minimizing the dimensions of the case main body 203 and hence the battery 201 in the wall thickness direction.

  Further, there is an advantage that the focal length can be easily stabilized by irradiating the laser toward the outer surface 262 of the flat lid 204. When the distance from the outer surface 262 of the lid 204 to the deepest portion of the welded portion 270 in the thickness direction of the lid 204 is defined as the penetration depth E3 of the welded portion 270, the focal length of the laser irradiation is stabilized as described above, The penetration depth E3 of the welded portion 270 is also stable, whereby a high joint strength can be obtained stably.

  Further, according to the second embodiment, in each battery 201, the lid 204 and the bead are prevented from protruding from the outer surface 252 of the wall portion 232, whereby the assembled battery 80, as shown in FIG. When assembling 90, the spacing between adjacent batteries 201, between battery 201 and end plate 82, and between battery 201 and spacer 98 can be minimized. As a result, the assembled batteries 80 and 90 are minimized in the stacking direction X.

  Further, according to the second embodiment, the formation of the bead 872 as in the first comparative example is prevented, so that special processing for avoiding interference with the bead 872 in the manufacture of the assembled batteries 80 and 90 is performed. Need not be applied to the end plate 82 and the spacer 98.

  In the second embodiment, the lid 204 covers the entire upper surface 254 and the support surface portion 242 of the wall portion 232, so that the width of the portion that supports the lid 204 in the wall portion 232 is larger than that of the first comparative example. Since it is enlarged, it is possible to reliably prevent the lid 204 temporarily placed on the wall portion 232 from falling off.

  Furthermore, in the second embodiment, in contrast to the second comparative example in which laser irradiation is performed along the wall thickness direction during welding, laser irradiation is performed along the thickness direction of the lid 204 that is thicker than the wall portion 232. Therefore, it is easy to ensure a large penetration depth E3 of the welded portion 270. Thereby, the penetration depth E3 is larger than the thickness E1 of the wall portion 232. Therefore, the bonding strength between the case main body 203 and the lid 204 can be increased.

  FIG. 10 shows an example in which the deepest portion of the welded portion 270 is positioned above the support surface portion 242, but the welded portion 270 has a deepest portion as indicated by a two-dot chain line 278. You may form so that it may be located below the support surface part 242. In this case, the welded portion 270 supports the inner surface 261 of the lid 204 and the wall portion 232 in addition to the interface between the outer peripheral surface 268 of the inner fitting portion 265 of the lid 204 and the inner surface 253 of the protruding portion 243 of the wall portion 232. Since the interface with the surface portion 242 is included, the bonding strength between the case main body 203 and the lid 204 can be increased.

  Further, as shown in FIG. 16, in the battery 901 according to the second comparative example, the opening peripheral portion of the case body 903 is moved outward in the wall thickness direction due to the expansion of the electrode body (not shown) accommodated in the exterior body 902. When pushed out, the gap between the inner surface 951 of the wall portion 940 and the outer peripheral surface 908 of the inner fitting portion 907 of the lid 904 may expand. Therefore, the laser irradiated from the side during welding easily enters the case main body 903 through the gap between the outer peripheral surface 908 of the inner fitting portion 907 and the inner surface 951 of the wall portion 940.

  On the other hand, in the second embodiment, even if the peripheral edge of the opening of the case body 203 is pushed outward in the wall thickness direction due to the expansion of the electrode body 10, the support surface portion 242 of the wall portion 232 and the inner surface 261 of the lid 204 Since the gap does not widen, it is difficult for the laser irradiated during welding to pass through the gap. Thereby, the penetration | invasion of the laser into the case main body 203 is suppressed, and the bad influence to the performance of the electrode body 10 by a laser can be prevented.

  In the second embodiment, the cutout portion 241 of the wall portion 232 and the cutout portion 263 of the lid 204 are L-shaped in cross section, and the support surface portion 242 of the wall portion 232 and the lower surface 266 of the peripheral edge portion 264a of the lid 204 are in the wall thickness direction. However, the shapes of the notches 241, 263, the support surface 242 of the wall 232, and the lower surface 266 of the peripheral edge 264a of the lid 204 are the same as the shape of the inner surface 261 of the lid 204 and the wall. The shape can be appropriately changed according to the shape of the upper surface 254 of the protruding portion 243 of 232.

[Third Embodiment]
With reference to FIGS. 11 and 12, the configuration of the exterior body 302 of the battery 301 according to the third embodiment, in particular, the configuration of the joint between the case main body 303 and the lid 304 constituting the exterior body 302 will be described.

  In the third embodiment, the configuration of the battery 301 other than the exterior body 302 is the same as that of the battery 1 according to the first embodiment. In the description of the third embodiment, the same components as those in the first embodiment are not described, and the same reference numerals as those in the first embodiment are given in FIGS. 11 and 12.

  Further, in the description of the third embodiment, the joint portion between the long side wall portion 332 and the lid 304 of the case main body 303 illustrated in FIGS. 11 and 12 will be described, and the joint portion between the short side wall portion and the lid 304 will be described. Illustration and description are omitted. In the following description, the long side wall portion 332 is also simply referred to as “wall portion 332”.

  As shown in FIG. 11, each wall portion 332 includes an inner surface 351 that faces the electrode body 10 accommodated in the exterior body 302, and an outer surface 352 that is located on the opposite side of the inner surface 351. The inner surface 351 and the outer surface 352 of the wall portion 332 are disposed substantially parallel to the thickness direction of the lid 304. On the outer surface 352 at the upper end of the wall portion 332, for example, a cutout portion 341 having an L-shaped cross section is formed.

  The wall portion 332 includes a wall portion main body 340 including a lower portion than the notch portion 341 in the wall portion 332. The outer portion in the wall thickness direction at the upper end of the wall body 340 is a support surface portion 342 that supports the lid 304. The support surface portion 342 is configured by a surface substantially parallel to the wall thickness direction.

  The wall portion 332 includes a protruding portion 343 that is located on the inner side in the wall thickness direction than the notch portion 341 in the wall portion 332. The protruding portion 343 has a wall thickness smaller than that of the wall portion main body 340 and is provided so as to protrude upward from the upper end of the wall portion main body 340. The upper end of the protrusion 343 constitutes the periphery of the opening of the case body 303.

  As shown in FIG. 12, the protruding portion 343 includes an outer surface 353 located on the inner side of the outer surface 352 of the wall portion main body 340. The outer surface 353 of the projecting portion 343 is adjacent to the support surface portion 342 via a substantially right-angled corner, and is disposed substantially parallel to the thickness direction of the lid 304. The protrusion 343 includes an upper surface 354 that is adjacent to the inner surface 351 and the outer surface 353 via corners that are substantially perpendicular to each other. An upper surface 354 of the protruding portion 343 is disposed substantially parallel to the wall thickness direction.

  As shown in FIG. 11, the lid 304 includes an inner surface 361 facing the electrode body 10 accommodated in the exterior body 302, and an outer surface 362 located on the opposite side of the inner surface 361. The inner surface 361 and the outer surface 362 of the lid 304 are disposed substantially parallel to the thickness direction of the wall portion 332.

  The lid 304 includes a rectangular plate-like lid main body 363 disposed above the upper end of the wall portion 332, and a rectangular frame-shaped outer fitting portion 364 that projects downward from the peripheral edge of the lid main body 363. . The lid 304 is attached to the upper end portion of the case main body 303 so that the outer fitting portion 364 is positioned on the inner side of the lid main body 363 in the lid thickness direction. Accordingly, the outer fitting portion 364 is disposed so as to be fitted to the outside of the case main body 303, specifically, the outside of the protruding portion 343 of the wall portion 332.

  As shown in FIG. 12, the outer peripheral surface 367 of the lid 304 is a flat surface that continues from the lid body 363 to the outer fitting portion 364. The outer peripheral surface 367 of the lid 304 is configured by a plane substantially parallel to the lid thickness direction, and is arranged so as to be continuous on the same plane as the outer surface 352 of the wall portion 332. That is, the lid 304 is disposed so as not to protrude outward in the wall thickness direction from the outer surface 352 of the wall portion 332.

  The outer fitting portion 364 of the lid 304 is configured by a rectangular section having a wall thickness smaller than that of the wall main body 340. The outer fitting portion 364 includes an inner surface 368 that faces the outer surface 353 of the protruding portion 343 of the wall portion 340, and a lower surface 369 that is adjacent to the inner surface 368 through a substantially right-angled corner. The inner surface 368 of the outer fitting portion 364 is a surface that is substantially parallel to the lid thickness direction, is disposed substantially parallel to the outer surface 353 of the protrusion 343, and covers substantially the entire outer surface 353 from the outside in the wall thickness direction. The lower surface 369 of the outer fitting portion 364 is a surface substantially parallel to the inner surface 361 and the outer surface 362 of the lid 304, and is disposed substantially parallel to the support surface portion 342 of the wall portion 332. Covering. As described above, the outer fitting portion 364 is engaged with the wall portion 332 in a state of being located outside the case main body 303.

  The peripheral edge portion of the lower surface 361 of the lid body 363 covers the entire upper surface 354 of the protruding portion 343 of the wall portion 332 from the upper side. As a result, the lid 304 is supported by the wall portion 332 in a state of being in contact with substantially the entire upper surface 354 of the wall portion 332 and substantially the entire supporting surface portion 342.

  The lid 304 is supported over the entire circumference by the pair of long side wall portions 332 and the pair of short side wall portions. Thereby, when the lid 304 is welded to the case main body 303, the entire peripheral edge portion of the lid 304 can be temporarily placed on the wall portion 332. By this temporary placement, the outer fitting portion 364 of the lid 304 is fitted to the opening peripheral edge portion of the case main body 303 from the outside. Accordingly, the lid 304 can be accurately positioned with respect to the case main body 303, and the lid 304 can be reliably prevented from falling into the case main body 303.

  The thickness F2 of the lid main body 363 of the lid 304 is larger than the thickness F1 of the wall main body 340 of the wall portion 332 of the case main body 303. For example, the thickness F1 of the wall portion 332 is 0.5 mm or more and less than 1.0 mm, and the thickness F2 of the lid 304 is 1.0 mm or more and less than 2.0 mm.

  The lid 304 is welded to the upper end portion of the wall portion 332 of the case main body 303 by laser irradiation from the outside in the thickness direction. Specifically, laser is irradiated from above toward the outer surface 362 of the lid main body 363 along a direction parallel to the thickness direction of the lid 304, so that the welded portion 370 extends in the thickness direction of the lid 304. It is formed. The welded portion 370 is formed so as to be located on the inner side of the outer surface 352 of the wall portion 332 from the outer surface 362 of the lid body 363 to the interface between the lid 304 and the wall portion 332.

  The welded portion 370 may be formed so as to include an interface between the inner surface 368 of the outer fitting portion 364 of the lid 304 and the outer surface 353 of the protruding portion 343 of the wall portion 332 arranged substantially parallel to the lid thickness direction. preferable. In this case, the area of the interface between the lid 304 and the wall portion 332 included in the welded portion 370 can be increased, and thereby the bonding strength between the lid 304 and the wall portion 332 can be increased.

  With the configuration of the exterior body 302 described above, the battery and the assembled battery according to the third embodiment have various functions and effects. Hereinafter, the effects of the third embodiment are compared with the battery 801 according to the first comparative example (see FIGS. 13 and 14) and the battery 901 according to the second comparative example (see FIGS. 15 and 16). While explaining.

  In the third embodiment, in contrast to the first comparative example in which laser is irradiated toward the boundary portion between the lid 804 and the protruding portion 843 of the wall portion 830 at the time of welding, toward the outer surface 362 of the flat lid 304. Since the laser is irradiated, it is possible to prevent the molten material from drooping outward in the wall thickness direction while securing a sufficient amount of penetration. This prevents the formation of a bead that protrudes from the outer surface 352 of the wall portion 332, thereby minimizing the dimensions of the case main body 303 and hence the battery 301 in the wall thickness direction.

  Further, there is an advantage that the focal length can be easily stabilized by irradiating the laser toward the outer surface 362 of the flat lid 304. When the distance from the outer surface 362 of the lid 304 in the thickness direction of the lid 304 to the deepest portion of the welded portion 370 is defined as the penetration depth F3 of the welded portion 370, the focal length of the laser irradiation is stabilized as described above, The penetration depth F3 of the welded portion 370 is also stable, whereby a high joint strength can be obtained stably.

  Furthermore, according to the third embodiment, in each battery 301, the protrusion of the lid 304 and the bead from the outer surface 352 of the wall portion 332 is prevented, whereby the assembled battery 80, as shown in FIG. When assembling 90, the spacing between adjacent batteries 301, between batteries 301 and end plate 82, and between batteries 301 and spacer 98 can be minimized. As a result, the assembled batteries 80 and 90 are minimized in the stacking direction X.

  Further, according to the third embodiment, the formation of the bead 872 as in the first comparative example is prevented, so that special processing for avoiding interference with the bead 872 in the manufacture of the assembled batteries 80 and 90 is performed. Need not be applied to the end plate 82 and the spacer 98.

  Furthermore, in the third embodiment, in contrast to the second comparative example in which laser irradiation is performed along the wall thickness direction during welding, laser irradiation is performed along the thickness direction of the lid 304 that is thicker than the wall portion 332. Therefore, it is easy to ensure a large penetration depth F3 of the welded portion 370. Thereby, the penetration depth F3 is larger than the thickness F1 of the wall portion 332. Therefore, the bonding strength between the case main body 303 and the lid 304 can be increased.

  FIG. 12 shows an example in which the deepest portion of the welded portion 370 is positioned above the support surface portion 342, but the welded portion 370 has a deepest portion as indicated by a two-dot chain line 378. You may form so that it may be located below the support surface part 342. FIG. In this case, in addition to the interface between the inner surface 368 of the outer fitting portion 364 of the lid 304 and the outer surface 353 of the protruding portion 343 of the wall portion 332, the welded portion 370 includes a lower surface 369 of the outer fitting portion 364 of the lid 304. Since the interface between the wall portion 332 and the support surface portion 342 is included, the bonding strength between the case main body 303 and the lid 304 can be increased.

  Further, as shown in FIG. 16, in the battery 901 according to the second comparative example, the opening peripheral portion of the case body 903 is moved outward in the wall thickness direction due to the expansion of the electrode body (not shown) accommodated in the exterior body 902. When pushed out, the gap between the inner surface 951 of the wall portion 940 and the outer peripheral surface 908 of the inner fitting portion 907 of the lid 904 may expand. Therefore, the laser irradiated from the side during welding easily enters the case main body 903 through the gap between the outer peripheral surface 908 of the inner fitting portion 907 and the inner surface 951 of the wall portion 940.

  On the other hand, in the third embodiment, since the outer fitting portion 364 of the lid 304 restricts the movement of the wall portion 332 to the outside, even if the electrode body 10 expands, the opening peripheral edge of the case body 303 It is suppressed that the part is pushed outward in the wall thickness direction. Therefore, a gap is prevented from being generated between the upper surface 354 of the wall portion 332 and the inner surface 361 of the lid 304, and the laser irradiated during welding is prevented from entering the case body 303 through the gap. The

  In the third embodiment, an example in which the cutout portion 341 of the wall portion 332 has an L-shaped cross section and the outer fitting portion 364 of the lid 304 has a rectangular cross section has been described, but the cutout portion 341 and the outer fitting portion 364 are described. The shape can be appropriately changed according to the mutual shape.

  While the present invention has been described with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments.

  For example, in the first to third embodiments described above, the example in which the outer peripheral surface of the lid is disposed on the same surface as the outer surface of the wall portion of the case main body has been described, but the outer peripheral surface of the lid is more than the outer surface of the wall portion. You may arrange | position inside a wall thickness direction.

  In the first to third embodiments, the example in which the bonding structure between the long side wall portion and the lid of the case body is the same as the bonding structure between the short side wall portion and the lid has been described. May be different from each other.

  Furthermore, in said 1st-3rd embodiment, although the electrical storage element which concerns on this invention was demonstrated to the lithium ion secondary battery as an example, this invention is a secondary battery other than a lithium ion secondary battery, a primary battery, It can be applied to various power storage elements including capacitors.

1 Battery (storage element)
2 Exterior body 3 Case body 3a Opening 4 Lid 10 Electrode body 14 Negative electrode external terminal 15 Positive electrode external terminal 16 Upper packing 18 Lower packing 20 Negative electrode current collector 21 Positive electrode current collector 31 Bottom wall portion 32 Long side wall portion 33 Short side wall portion 51 Inner surface of the wall portion 52 Outer surface of the wall portion 53 Upper surface of the wall portion 61 Inner surface of the lid 62 Outer surface of the lid 64 Lid body 64a Peripheral portion of the lid body 65 Inner fitting portion (engagement portion)
66 Lower surface of peripheral edge of lid main body 67 Outer peripheral surface of lid main body 68 Outer peripheral surface of inner fitting portion 70 Welded portion 80, 90 Battery pack (power storage device)
82 End plate 84 Restraint band 86 Bus bar 98 Spacer 104 Lid 165 Inner fitting part (engagement part)
201 Battery (electric storage element)
202 exterior body 203 case body 204 lid 232 wall portion 240 wall portion body 241 cutout portion 242 support surface portion 243 projection portion 251 inner surface of wall portion 252 outer surface of wall portion 253 inner surface of projection portion 254 upper surface of projection portion 261 inner surface of lid 262 lid Outer surface 263 Notch portion 264 Cover body 264a Peripheral edge 265 of cover body Inner fitting section (engagement section)
266 The lower surface of the peripheral part of the lid body 267 The outer peripheral surface of the lid main body 268 The outer peripheral surface of the inner fitting part 270 Welding part 301 Battery (power storage element)
302 exterior body 303 case main body 304 lid 332 wall portion 340 wall main body 341 notch 342 support surface portion 343 projecting portion 351 inner surface of wall portion 352 outer surface of wall portion 353 outer surface of projecting portion 354 upper surface of projecting portion 361 inner surface of lid 362 lid External surface 363 Lid body 364 Outer fitting part (engagement part)
367 Outer peripheral surface of lid 368 Inner surface of outer fitting portion 369 Lower surface of outer fitting portion 370 Welded portion

Claims (7)

A case main body including a wall portion whose tip constitutes the periphery of the opening, and an electrode body accommodated therein;
A lid for closing the opening of the case body,
The lid includes a lid body that covers the tip of the wall portion of the case body, and an engaging portion that is positioned on the inner side in the thickness direction of the lid body than the lid body and engages with the wall portion,
A power storage element, wherein a welded portion is formed so as to be located on an inner side of an outer surface of the wall portion from an outer surface of the lid body to an interface between the lid and the wall portion.   The electric storage element according to claim 1, wherein the engaging portion of the lid is engaged with the wall portion in a state of protruding from the opening into the case main body.   The electric storage element according to claim 2, wherein the engaging portion of the lid is engaged with an inner surface of the wall portion. A notch is formed on the inner surface of the tip of the wall,
The electric storage element according to claim 2, wherein the engaging portion of the lid is engaged with the cutout portion.   The power storage element according to claim 1, wherein the engaging portion of the lid is engaged with the wall portion in a state of being located outside the case main body.   6. The power storage device according to claim 1, wherein a depth of the welded portion in a thickness direction of the lid main body is larger than a wall thickness of the wall portion. A plurality of power storage elements according to any one of claims 1 to 6,
The power storage device, wherein the plurality of power storage elements are overlapped in a thickness direction of the wall portion.

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