JP6103225B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device in which an electrode terminal is fixed to a wall portion of a case through fastening of a fastening member such as a nut.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover.

  As the secondary battery, one described in Patent Document 1 is known. The electrode terminal of the secondary battery has a pole column portion provided with a collar portion protruding in the circumferential direction at one end. The pole column portion is attached to the case in a state of being inserted into the insertion hole of the case and the tip of the pole column portion protruding to the outside of the case.

  An insulating member made of an electrically insulating material (for example, polypropylene) is attached to the insertion hole of the case. The insulating member has an insertion portion extending between the inner surface of the insertion hole of the case and the outer surface of the pole column portion, and a flange portion protruding from the insertion portion and extending along the outer surface of the case. In this secondary battery, the fastening member for fixing the electrode terminal is fastened and fixed to the pole column portion from the outside of the case in a state where the flange portion of the insulating member is sandwiched between the outer surface of the case. Thereby, the flange part of an insulating member functions as a member for electrically insulating between a case and a fastening member.

  Moreover, in the thing of patent document 1, in order to ensure the electrical insulation between such a case and a fastening member, while the flange part of an insulating member becomes a shape extended to the outer edge of the said fastening member, the same The peripheral wall portion has a shape protruding from the flange portion and extending along the peripheral wall of the fastening member.

  In addition, as a prior art document concerning this invention, the following patent documents 2 other than the said patent document 1 are mentioned.

JP 2009-48967 A JP 2002-304973 A

  Here, in the secondary battery, in order to improve the airtightness of the case, the case may be welded after various parts such as electrode terminals and an electrode assembly are attached to the wall portion of the case. Although the secondary battery described in Patent Document 1 is used to increase the insulation performance between the case and the fastening member, the insulating member is formed in a shape that covers the periphery of the fastening member. The outer edge of the case tends to be close to the welded part in the case. As a result, when the case is welded at the time of manufacturing the secondary battery, the insulating member has a structure that is easily affected by the heat caused by the welding, and in some cases, the insulating member may be thermally deformed. This is not preferable because it causes a decrease in insulation performance due to the insulating member and a decrease in fastening force due to the fastening member.

  This invention was made paying attention to the problem which exists in the said prior art, The objective is suppressing the thermal deformation of the insulation member resulting from the welding process of a case, maintaining the insulation performance by an insulation member. An object of the present invention is to provide a power storage device that can be used.

Hereinafter, a power storage device for achieving the above-described object has an insertion hole that communicates the inside and the outside, a case having a welded welded portion, and a pole column, and one end of the pole column is When supported by the said case both in a state where the other end of the pole portion is inserted into the insertion hole, an electrode terminal projected out of the casing, a fastening member that is fastened to the pole portion An insertion portion extending between the inner surface of the insertion hole and the outer surface of the pole post portion, and extending along the outer surface of the case protruding from the insertion portion and sandwiched between the outer surface of the case and the fastening member And an insulating member having a peripheral wall portion protruding from the flange portion and covering a part of the peripheral wall of the fastening member, wherein the insulating member is opposed to the outer surface of the case The outer part whose surface is far from the insertion hole Ri has a step portion of the stepped shape close inner portion into the insertion hole is projected, only the projecting portion projecting on the outer surface of the case in the stepped portion is in contact with the outer surface of the casing, inside the casing The case and the electrode are arranged at the periphery of the insertion hole, and are formed of a seal member having a shape extending over the entire circumference of the pole column portion and a material harder than the seal member, and extending in the periphery of the seal member. An interposing member interposed between the flange of the terminal, and a portion where the protruding portion is in contact with the case in the direction in which the fastening member is fastened is arranged with the seal member It overlaps with the whole outer edge of a part, and the said interposed member overlaps with at least one part of the part which is contacting the said case .

  In the power storage device, the fastening member is fastened and fixed to the pole column in a state where the protruding portion of the step portion of the flange portion of the insulating member, that is, the portion close to the insertion hole is sandwiched between the case and the fastening member. . Thereby, since the outer part far from the said insertion hole of an insulating member becomes a structure which does not contact a case, the outer edge of the contact part which a case and a flange part are contacting can be made into the position near the said insertion hole. Therefore, it becomes possible to place the contact portion of the flange portion of the insulating member with the case far from the welded portion of the case, and the insulating member is less susceptible to the heat effect caused by the case welding process. Thus, thermal deformation of the insulating member can be suppressed. In addition, although the outer portion of the insulating member does not contact the case, the portion other than the protruding portion of the flange portion of the insulating member and the peripheral wall portion protruding from the flange portion provide a space between the fastening member and the case. Since it can block over a wide range, high insulation performance can also be obtained by the insulating member. As described above, according to the power storage device, it is possible to suppress thermal deformation of the insulating member due to welding of the case while maintaining the insulating performance of the insulating member.

  According to the power storage device, through the fastening and fixing of the fastening member to the pole column portion, the entire peripheral portion of the insertion hole in which the seal member is disposed inside the case is formed by the protruding portion of the flange portion of the insulating member. It can be pressed from the fastening direction. Thereby, the fastening force which generate | occur | produces by the fastening fixation of a fastening member can be made to act appropriately on the space in which a sealing member is installed. Therefore, the sealing function by the sealing member can be properly exhibited.

  In the power storage device, when the fastening member is fastened and fixed, the outer edge of the protruding portion of the flange portion of the insulating member is supported by the sandwiching portion that sandwiches the interposed member in the case. Accordingly, the gap between the case and the flange of the electrode terminal in the portion on the pole column side from the interposition member in the case, in other words, the length in the fastening direction of the space where the seal member is installed is the same. It becomes possible to determine with high precision by the interposed member interposed in the gap. According to the power storage device, since the sealing member made of a relatively soft forming material can be disposed in an installation space accurately defined by the interposed member made of a hard forming material, the deformation amount of the sealing member can be reduced. It is possible to properly manage the seal function of the seal member.

In the power storage device, the flange portion can be formed in a stepped cylindrical shape.
According to the power storage device, since the insulating member has a simple shape, the insulating member can be easily manufactured. And since it is not necessary to consider the position of the circumferential direction of an insulating member at the time of attachment to the insertion hole of a case, the attachment operation | work can be performed easily.

Further, in the power storage device, the flange portion includes a first region formed in a step shape in which an inner portion close to the insertion portion protrudes to an outer surface side of the case from an outer portion far from the insertion portion, and the insertion portion And a second region that is not formed in a stepped shape that protrudes toward the outer surface side of the case from an outer portion far from the insertion portion, and the first region is more welded than the second region. It is preferable that it is arrange | positioned adjacent to .
According to the above power storage device, since the portion of the flange portion that is close to the welded portion of the case is likely to have a high temperature during the welding process, it can be formed in a stepped shape, and thus the thermal deformation of the insulating member can be accurately suppressed. Can do. Moreover, since the flange portion is far from the welded portion of the case, the portion having a relatively low temperature during the welding process is not formed in a step shape. This makes it possible to increase the contact area of the flange portion with the case compared to the case where the entire circumference of the flange portion is formed in a stepped shape, and the fastening member is fastened to the pole column portion accordingly. Since the force can be increased, the electrode terminal can be firmly fixed to the case.
Further, in the above power storage device, the flange portion has a cylindrical shape in which an inner portion close to the insertion portion protrudes toward an outer surface side of the case from an outer portion far from the insertion portion, and a protruding portion protruding toward the outer surface side of the case A plurality of wall portions extending in the radial direction of the insertion portion from the outer peripheral surface of the insertion portion.
Further, in the above power storage device, the flange portion has a cylindrical shape in which an inner portion close to the insertion portion protrudes to the outer surface side of the case from an outer portion far from the insertion portion, and protrudes to the outer surface side of the case The thickness in the axial direction decreases from the portion toward the outer edge of the flange portion.

  The power storage device can be applied to a secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal deformation of the insulation member resulting from the welding process of a case can be suppressed, maintaining the insulation performance by an insulation member.

The disassembled perspective view which shows the secondary battery of one Embodiment. The perspective view which shows the external appearance of a secondary battery. The perspective view which shows the component of an electrode assembly. Sectional drawing which shows the pole column part periphery of an electrode terminal. The insulating member (a) bottom view, (b) side view. Sectional drawing which expands and shows the periphery of an insulating member. (A) Bottom view of insulating member of other embodiment, (b) Side surface sectional view along line 7b-7b in (a) of the insulating member. (A) Bottom view of insulating member of other embodiment, (b) Side cross-sectional view along line 8b-8b in (a) of the insulating member. (A) Bottom view of insulating member of other embodiment, (b) Side cross-sectional view along line 9b-9b in (a) of the insulating member. Sectional drawing which shows the periphery of the insulating member of other embodiment.

Hereinafter, an embodiment in which the power storage device is embodied as a secondary battery will be described.
As shown in FIG. 1 or 2, in the secondary battery 10, an electrode assembly 20 is accommodated in a metal case 12. The case 12 includes a rectangular parallelepiped case main body 13 having an opening 13 d and a rectangular flat plate-shaped lid 14 that closes the opening 13 d of the case main body 13. The case main body 13 and the lid 14 are both made of metal (for example, stainless steel or aluminum). ing. The case body 13 includes a rectangular bottom plate 13a, a short side wall 13b erected from a pair of opposed short side edges of the bottom plate 13a, and a long side wall 13c erected from a pair of long side edges of the bottom plate 13a. With. The lid 14 has a pair of insertion holes 14b arranged in parallel at a predetermined interval. Further, the secondary battery 10 of the present embodiment is a prismatic battery whose outer periphery forms a square shape. Further, the secondary battery 10 of the present embodiment is a lithium ion battery.

  As shown in FIG. 3, the electrode assembly 20 includes a positive electrode 21 and a negative electrode 22, and a laminated body having a layer shape with a separator 23 interposed between the positive electrode 21 and the negative electrode 22. Has been. The positive electrode 21 includes a rectangular metal foil for positive electrode (in this embodiment, an aluminum foil) 21a, and a positive electrode active material layer 21b formed on both surfaces of the metal foil for positive electrode 21a. The negative electrode 22 includes a rectangular negative electrode metal foil (copper foil in the present embodiment) 22a and negative electrode active material layers 22b formed on both surfaces of the negative electrode metal foil 22a.

  A positive electrode current collecting tab 31 formed by extending the positive electrode metal foil 21 a is provided in a part of one side direction (long side direction) of the positive electrode 21. The positive electrode current collecting tab 31 is formed in the same position and in the same shape in each positive electrode 21 constituting the electrode assembly 20. A part of one side direction (long side direction) of the negative electrode 22 is provided with a negative electrode current collecting tab 32 formed by extending the negative electrode metal foil 22a. The negative electrode current collecting tab 32 is formed in the same position and in the same shape in each negative electrode 22 constituting the electrode assembly 20.

  The positive electrodes 21 constituting the electrode assembly 20 are stacked such that the respective positive electrode current collecting tabs 31 are arranged in a line along the stacking direction. Similarly, the negative electrode 22 constituting the electrode assembly 20 is laminated so that the respective negative electrode current collecting tabs 32 are arranged in a row along the lamination direction so as not to overlap the positive electrode current collecting tabs 31. . The plurality of positive electrode current collecting tabs 31 are collected in a range from one end to the other end of the electrode assembly 20 in the stacking direction. Similarly, the plurality of negative electrode current collecting tabs 32 are collected in a range from one end to the other end in the stacking direction of the electrode assembly 20.

  As shown in FIG. 1, the electrode assembly 20 includes a positive electrode tab group 45 formed by collecting positive electrode current collecting tabs 31. The positive electrode tab group 45 is welded to the positive electrode conductive member 33. The electrode assembly 20 includes a negative electrode tab group 46 formed by collecting the negative electrode current collecting tabs 32. The negative electrode tab group 46 is welded to the negative electrode conductive member 37.

  As shown in FIG. 1 or FIG. 4, the positive electrode conductive member 33 and the negative electrode conductive member 37 have a terminal connection portion 34 having a square plate shape. In the terminal connecting portion 34, a surface to which a positive electrode terminal 41 or a negative electrode terminal 42 as an electrode terminal described later is welded is a first surface 34a, and a surface opposite to the first surface 34a is a second surface 34b. The positive electrode conductive member 33 and the negative electrode conductive member 37 have a rising portion 35 that rises from the second surface 34 b toward the first surface 34 a, and tab welding that extends from the rising portion 35 in a direction away from the terminal connection portion 34. A portion 36 is provided. The tab weld 36 is a rectangular plate.

  The positive electrode terminal 41 is welded to the terminal connection portion 34 of the positive electrode conductive member 33, and the negative electrode terminal 42 is welded to the terminal connection portion 34 of the negative electrode conductive member 37. The positive electrode terminal 41 and the negative electrode terminal 42 each have a flange portion 43 having an octagonal plate shape, and the planar shape of the flange portion 43 is substantially the same as the planar shape of the first surface 34 a in each terminal connection portion 34. In the flange portion 43, a surface facing the inner surface 14a of the lid 14 is a seat surface 43a, and a surface opposite to the seat surface 43a in the thickness direction of the flange portion 43 is an assembly side end surface 43b.

  A cylindrical pole post 44 is erected from the center of the flange 43, and a seating surface 43 a surrounds the pole post 44. The pole portion 44 has a male screw 44a on the outer peripheral surface and a female screw 44b as a screw groove on the inner peripheral surface. The male screw 44a and the female screw 44b are reverse screws.

  A terminal cover 50 made of a synthetic resin (for example, polyphenylene sulfide [PPS] or polypropylene [PP]) is attached to the collar portion 43. The terminal cover 50 includes a lid-side insulating plate 51 that is disposed between the seat surface 43 a of the flange portion 43 and the inner surface 14 a of the lid 14. The lid-side insulating plate 51 has an insertion portion 51a into which the pole column portion 44 is inserted, and the inner peripheral edge of the lid-side insulating plate 51 is arcuate. The lid-side insulating plate 51 has a cut-out communication portion 51b that opens the insertion portion 51a to one side of the lid-side insulation plate 51. The lid-side insulation plate 51 is flat by the insertion portion 51a and the communication portion 51b. It has a U-shape. The lid-side insulating plate 51 has, on its inner edge, a protruding portion 51c that faces the communication portion 51b and protrudes toward the communication portion 51b.

  The lid-side insulating plate 51 includes a case-side insulating plate 52 at an edge located on the opposite side to the communicating portion 51b with the insertion portion 51a interposed therebetween, and the case-side insulating plate 52 is separated from the lid 14. Extends in the direction. The case side insulating plate 52 has a rectangular plate shape and extends perpendicularly to the lid side insulating plate 51. In the case-side insulating plate 52, an assembly-side insulating plate 53 extends in the same direction as the lid-side insulating plate 51 and along the assembly-side end surface 43 b at the distal end on the side away from the lid 14. The case side insulating plate 52 is formed in a rectangular plate shape. The terminal cover 50 configured as described above is attached to the positive terminal 41 and the negative terminal 42 from the side of the short side wall 13b of the case body 13.

  The pole column portion 44 is inserted into the insertion portion 51 a of the lid side insulating plate 51, and the lid side insulating plate 51 surrounds almost the entire circumference of the pole column portion 44. The lid-side insulating plate 51 is supported on the seating surface 43 a of the flange portion 43. On the seating surface 43 a of the flange portion 43, a synthetic rubber O-ring 56 as a sealing member is provided so as to surround the entire circumference of the pole column portion 44. The O-ring 56 is disposed in the insertion portion 51 a of the lid-side insulating plate 51, and substantially entirely surrounded by the lid-side insulating plate 51. That is, the O-ring 56 is surrounded by the inner peripheral edge of the lid-side insulating plate 51 except for the portion facing the communication portion 51b. The assembly-side insulating plate 53 is disposed closer to the electrode assembly 20 than the assembly-side end surface 43b of the flange 43, and extends along the assembly-side end surface 43b opposite to the seating surface 43a. The assembly-side insulating plate 53 is interposed between the flange 43 and the electrode assembly 20.

  The lid 14, the positive terminal 41, and the negative terminal 42 are electrically insulated by the lid-side insulating plate 51 in the terminal cover 50. In addition, the case main body 13 is electrically insulated from the positive terminal 41 and the negative terminal 42 by the case-side insulating plate 52. Further, the assembly side insulating plate 53 electrically insulates the electrode assembly 20 from the positive terminal 41 and the negative terminal 42.

  The tip of the pole post 44 inserted into the insertion part 51a of the lid-side insulating plate 51 protrudes outside the case 12 from an insertion hole 14b provided in the lid 14 so as to communicate the inside and outside of the case 12 ( Exposed). The flange portions 43 of the positive electrode terminal 41 and the negative electrode terminal 42 are provided at one end located inside the case main body 13 among both ends of the pole column portion 44. Moreover, the collar part 43 is set so that the cross-sectional area parallel to the lid | cover 14 is larger than the opening area of the penetration hole 14b. For this reason, the collar part 43 cannot be pulled out from the insertion hole 14 b inside the case main body 13. The inner peripheral surface of the insertion hole 14 b of the lid 14 and the outer peripheral surface of the pole column portion 44 are insulated by the insulating member 19.

  The insulating member 19 includes a cylindrical portion 24 as a cylindrical insertion portion, an annular flange portion 25 extending radially outward from one axial end of the cylindrical portion 24, and the flange portion 25. And a cylindrical peripheral wall portion 26 protruding in the axial direction from the outer edge of the outer peripheral edge. In this insulating member 19, the tubular portion 24 extends between the inner peripheral surface of the insertion hole 14 b and the outer peripheral surface of the pole column portion 44, and the flange portion 25 extends along the outer surface 14 c of the lid 14 of the case 12. The lid 14 is provided so as to extend. A nut 55 as a fastening member is screwed to the male screw 44 a of the pole column portion 44, and the nut 55 is attached (fastened and fixed) to the pole column portion 44.

  In the secondary battery 10, the cylindrical portion 24 interposed between the inner peripheral surface of the insertion hole 14 b of the lid 14 and the outer peripheral surface of the pole column portion 44 is sandwiched between the nut 55 and the lid 14. The nut 55 and the lid 14 are insulated by the flange portion 25 and the peripheral wall portion 26 extending along the peripheral wall of the nut 55. Further, the nut 55 is screwed into the male screw 44 a of the pole post 44, so that the flange 25, the lid 14, the lid-side insulating plate 51, and the O-ring are provided between the nut 55 and the flange 43 of the pole post 44. The pole post 44 is fastened and fixed to the lid 14 in a state where 56 is tightly pressed. The O-ring 56 in the fastened state is in close contact with the inner surface 14a of the lid 14 and the seating surface 43a of the flange portion 43 in a compressed state to seal the periphery of the insertion hole 14b.

Next, the insulating member 19 will be described in detail.
The insulating member 19 has a stepped portion 27 on a facing surface 25 a that faces the outer surface 14 c of the lid 14 in the flange portion 25.

  As shown in FIG. 5, the stepped portion 27 of the insulating member 19 has a stepped cylindrical shape, and a stepped shape in which an inner portion 28 close to the tubular portion 24 protrudes from an outer portion 29 far from the tubular portion 24. It is.

  As shown in FIG. 4 or FIG. 6, in the secondary battery 10, only the inner portion 28 that protrudes toward the outer surface 14 c of the lid 14 in the stepped portion 27 is in contact with the outer surface 14 c. Specifically, the opposing surface 25a of the insulating member 19 has a stepped shape in which the inner portion 28 near the insertion hole 14b protrudes compared to the outer portion 29 far from the insertion hole 14b of the lid 14 in the stepped portion 27. Only the inner portion 28 of the outer portion 29 and the inner portion 28 is in contact with the outer surface 14 c of the lid 14.

  Further, as shown in FIG. 6, the contact portion A in contact with the lid 14 in the inner portion 28 of the flange portion 25 of the insulating member 19 in the direction (vertical direction in the drawing) in which the nut 55 is screwed (fastened). However, it overlaps the entire outer edge of the portion where the O-ring 56 is disposed. Further, in the screwing direction (fastening direction) of the nut 55, the contact portion A of the flange portion 25 is over the part of the contact portion B where the lid-side insulating plate 51 of the terminal cover 50 is in contact with the lid 14. Wrapping. Further, in the screwing direction of the nut 55, the outer end of the contact portion C where the nut 55 is in contact with the flange portion 25 of the insulating member 19 and the outer end of the contact portion A of the flange portion 25 are Match.

Next, the operation of the secondary battery 10 will be described.
In the secondary battery 10, only the inner portion 28 (that is, only the portion close to the insertion hole 14 b of the lid 14) of the inner portion 28 and the outer portion 29 of the stepped portion 27 of the flange portion 25 is the same as the lid 14 and the nut 55. The nut 55 is fastened and fixed to the pole post 44 while being sandwiched between the two. As a result, since the outer portion 29 far from the insertion hole 14b on the facing surface 25a of the insulating member 19 does not come into contact with the lid 14, a secondary battery including a flat-plate-shaped flange portion that does not have the stepped portion 27; In comparison, the outer edge of the contact portion A where the lid 14 and the flange portion 25 are in contact is at a position close to the insertion hole 14b. Therefore, the temperature of the contact portion A at the time of welding can be lowered by the extent that the distance between the welded portion 15 of the case 12 and the contact portion A of the insulating member 19 is increased.

  For example, as in the secondary battery described in Patent Document 2, in order to suppress thermal deformation of the insulating member, a part of the lid of the case (a part between the welded portion and the electrode terminal) is thinned and welded. It may be possible to make it difficult to transfer heat from the portion to the insulating member. Such a structure is not preferable because the strength of the case is reduced.

  In the secondary battery 10, in the screwing direction of the nut 55, the outer peripheral end of the contact portion C of the nut 55 and the outer peripheral end of the contact portion A of the flange portion 25 coincide with each other. As a result, the portion that can reliably transmit the fastening force of the nut 55 to the lid 14 while suppressing unnecessary deformation of the flange portion 25 due to the pressing of the nut 55 can be maximized. Can be suitably performed.

According to the above embodiment, the following effects can be obtained.
(1) The opposing surface 25a of the flange portion 25 facing the outer surface 14c of the lid 14 is a stepped step in which an inner portion 28 near the insertion hole 14b of the lid 14 protrudes from an outer portion 29 far from the insertion hole 14b. A portion 27 is provided. Only the inner portion 28 of the stepped portion 27 is in contact with the outer surface 14 c of the lid 14. Therefore, the temperature of the outer edge portion of the contact portion A at the time of welding, that is, the portion closest to the welded portion, can be lowered by an amount corresponding to the distance between the welded portion 15 of the case 12 and the contact portion A of the insulating member 19 being increased. It is possible to suppress thermal deformation of the insulating member 19 due to welding. Moreover, although the outer portion 29 of the flange portion 25 of the insulating member 19 does not contact the lid 14 of the case 12, the outer portion 29 and the peripheral wall portion 26 allow a wide range between the nut 55 and the lid 14. Since it can block, high insulation performance can also be obtained by the insulating member 19. As described above, according to the secondary battery 10, it is possible to suppress thermal deformation of the insulating member 19 due to welding of the case 12 while maintaining high insulation performance by the insulating member 19.

  (2) In the screwing direction of the nut 55, the contact portion A of the insulating member 19 is made of a material harder than the O-ring 56 in a state where it overlaps the entire outer edge of the arrangement portion where the O-ring 56 is disposed. A part of the contact portion B of the terminal cover 50 is also overlapped. Thereby, when the nut 55 is fastened and fixed, the outer edge of the inner portion 28 of the flange portion 25 of the insulating member 19 holds the cover-side insulating plate 51 of the terminal cover 50 of the cover 14 of the case 12 (the above-mentioned holding portion) Supported by the contact part B). Therefore, the space between the lid 14 of the case 12 and the flange 43 of the electrode terminal in the portion closer to the pole column 44 than the lid-side insulating plate 51 in the case 12, in other words, the screw in the space where the O-ring 56 is installed. The length in the mating direction can be accurately determined by the lid-side insulating plate 51 interposed in the same gap. Therefore, since the O-ring 56 made of a relatively soft forming material can be disposed in the installation space precisely defined by the lid-side insulating plate 51 of the terminal cover 50 made of a hard forming material, The amount of deformation can be properly managed, and the sealing function by the O-ring 56 can be properly exhibited.

  (3) The flange portion 25 of the insulating member 19 is formed in a stepped cylindrical shape. Thereby, since the insulating member 19 becomes a simple shape, the insulating member 19 can be manufactured easily. Moreover, since it is not necessary to consider the circumferential position of the insulating member 19 when attaching the case 12 to the insertion hole 14b, the attaching operation can be easily performed.

The above embodiment may be modified as follows.
In the outer portion 29 far from the cylindrical portion 24 on the facing surface 25 a of the flange portion 25, the stepped portion 27 may not be provided over the entire circumference of the cylindrical portion 24. As an example of such an insulating member, as shown in FIGS. 7A and 7B, the insulating member 70 is a portion of the outer portion 72 of the flange portion 71 close to the welded portion 15 of the case 12 (the upper portion in FIG. 7A). , The left portion and the lower portion) have a stepped portion 73 having a step shape, while the portion far from the welded portion 15 of the case 12 (the right portion in FIG. 5A) does not have a stepped portion. By adopting such an insulating member 70, a portion of the flange portion 71 that is close to the welded portion 15 of the case 12 and is likely to have a high temperature during welding can be formed into a stepped shape. Can be accurately suppressed. Moreover, since the portion of the flange portion 71 is far from the welded portion 15 of the case 12, the portion having a relatively low temperature during the welding process does not have a step shape. Therefore, the contact area of the flange portion 71 with the lid 14 can be increased as compared with the stepped shape of the entire circumference of the flange portion 71, and the fastening force of the nut 55 is the same under that amount. The contact surface pressure per unit area can be reduced. Thereby, the fastening force by the nut 55 can be increased, so that the electrode terminal can be firmly fixed to the case 12.

In the screwing direction of the nut 55, the contact portion A (FIG. 6) of the insulating member 19 and the entire contact portion B of the terminal cover 50 may overlap.
The shape of the inner portion 28 of the flange portion 25 is not limited to a cylindrical shape, and may be an arbitrary shape such as a shape in which the outer shape of the cross section in the radial direction of the cylindrical portion 24 is a polygonal shape. Thereby, the shape of the insulating member can be set with a high degree of freedom. Therefore, by appropriately determining the shape, the outer edge of the contact portion A of the insulating member 19 is kept away from the welded portion 15 of the case 12 to suppress thermal deformation of the insulating member 19, and the lid 14 of the insulating member 19 By increasing the contact area, it is possible to suitably achieve both fastening and fixing with the nut 55 appropriately. As shown in FIGS. 8A and 8B as an example of such an insulating member, the insulating member 80 has a cylindrical portion 83 of the inner portion 82 of the flange portion 81 close to the tubular portion 24. Further, the portion of the inner portion 82 of the insulating member 80 far from the cylindrical portion 24 has a plurality of wall portions 84 extending in the radial direction of the cylindrical portion 24 starting from the outer peripheral surface of the portion 83.

  As shown in FIGS. 9A and 9B, the outer portion 92 of the flange portion 91 of the insulating member 90 has a shape in which the thickness in the axial direction becomes thinner toward the outer edge of the flange portion 91. It is good. Thereby, since the distance between the lid 14 and the flange portion 91 can be increased as the temperature of the outer surface 14c of the lid 14 increases, an excessive temperature rise in each part of the insulating member 90 can be accurately suppressed. . In addition, since the flange portion 91 can be made thicker at a portion closer to the insertion hole 14b where the temperature of the outer surface 14c of the lid 14 becomes lower, a decrease in strength of the insulating member 90 can also be suppressed.

  As shown in FIG. 10, if the contact portion AA of the flange portion 25 overlaps a part of the contact portion B of the terminal cover 50 in the screwing direction of the nut 55, the outer peripheral side of the contact portion AA The end portion may be positioned closer to the cylindrical portion 24 than the end portion on the outer peripheral side of the contact portion CC of the nut 55.

  ○ When the nut 55 is fastened and fixed, if the material for forming the O-ring 56 is a hard material to the extent that the installation space for the O-ring 56 can be secured, the contact portion A of the flange portion 25 is It does not have to overlap with the contact portion B, and the contact portion A only needs to overlap the entire outer edge of the arrangement portion where the O-ring 56 is disposed. According to such a secondary battery, the entire portion where the O-ring 56 is disposed between the case 12 and the electrode terminal is fixed to the flange portion 25 of the insulating member 19 through fastening and fixing of the nut 55 to the pole column portion 44. The inner portion 28 and the cylindrical portion 24 can be pressed from the screwing direction of the nut 55. Accordingly, the fastening force generated by fastening and fixing the nut 55 can be appropriately applied to the installation space of the O-ring 56, so that the sealing function by the O-ring 56 can be properly exhibited.

  In the above embodiment, the collar portion 43 is formed on the positive electrode terminal 41 and the negative electrode terminal 42, but the collar portion 43 is not necessarily essential. For example, the lower end of the pole column portion of the positive electrode terminal may be directly fixed to the positive electrode conductive member by welding or the like. In this case, the O-ring is sandwiched between the lid and the conductive member, and a rising portion is not formed on the conductive member in order to secure a gap between the O-ring and the lid.

  The insulating member 19 of the above embodiment is not limited to the secondary battery 10 in which the nut 55 is screwed into the pole column portion 44 in order to fasten and fix the electrode terminal to the case 12, but is a caulking member on the pole column portion of the electrode terminal The present invention can also be applied to a secondary battery that is caulked and fixed.

  The connection structure between the positive electrode current collecting tab 31 and the positive electrode conductive member 33 and between the negative electrode current collecting tab 32 and the negative electrode conductive member 37 is not limited to the structure described above. For example, after the positive electrode current collecting tabs 31 are collected and the positive electrode tab group 45 is electrically connected between the tabs, only the outermost positive electrode current collecting tab 31 may be connected to the positive electrode conductive member 33. . Similarly, on the negative electrode side, the negative electrode current collecting tabs 32 are collected to form a negative electrode tab group 46 in which the tabs are electrically connected, and then only the outermost negative electrode current collecting tab 32 is connected to the negative electrode conductive member 37. May be. The structure is not particularly limited as long as the positive electrode conductive member or the negative electrode conductive member and each positive electrode current collector tab or each negative electrode current collector tab are electrically connected.

  O Although the lid side insulating plate 51 of the said embodiment is made into U shape in planar view, it is not specifically limited to this shape. For example, when the lid-side insulating plate is separated from the case-side insulating plate and assembled separately, the lid-side insulating plate may have a shape with a through hole.

  Not only the O-ring 56 made of synthetic rubber, but also a seal member of any material and shape as long as it is a seal member capable of sealing between the electrode terminal and the lid 14 around the entire circumference of the pole column portion 44 Can be provided.

The number of the positive electrode 21 and the negative electrode 22 which comprise the electrode assembly 20 may be changed suitably.
The electrode assembly 20 is a winding type configured by interposing a strip-shaped separator 23 between a strip-shaped positive electrode 21 and a negative electrode 22 and winding them around a winding axis in a spiral manner. Also good.

The case 12 may be formed in a columnar shape or an elliptical columnar shape.
The power storage device may be embodied as a nickel hydride secondary battery or an electric double layer capacitor.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 12 ... Case, 14 ... Cover, 14b ... Insertion hole, 14c ... Outer surface, 15 ... Welding part, 19, 70, 80, 90 ... Insulating member, 24 ... Tube as insertion part 25, 71, 81, 91 ... flange portion, 25a ... opposing surface, 26 ... peripheral wall portion, 27, 73 ... step portion, 28, 82 ... inner portion, 29, 72, 92 ... outer portion, 41 ... electrode Positive terminal as a terminal, 42... Negative terminal as an electrode terminal, 43 .. collar part, 44... Pole column part, 44 a... Male screw, 50... Terminal cover as an interposed member, 55. O-ring as.

Claims (6)

An insertion hole communicating the inside and the outside, and a case having a welded welded portion;
Has a pole portion, both the one end of the pole column portion is supported by the said case, while inserting the other end of the pole section to the insertion hole, the electrode terminal projected out of the casing When,
A fastening member fastened and fixed to the pole post;
An insertion portion extending between the inner surface of the insertion hole and the outer surface of the pole column portion, and protruding from the insertion portion and extending along the outer surface of the case, and is sandwiched between the outer surface of the case and the fastening member An insulating member having a flange portion and an insulating member that protrudes from the flange portion and covers a part of the peripheral wall of the fastening member.
The insulating member has a stepped portion having a stepped shape in which an opposing surface facing the outer surface of the case protrudes from an outer portion far from the insertion hole and an inner portion closer to the insertion hole, and the outer surface of the case at the stepped portion Only the protruding part protruding to the side is in contact with the outer surface of the case ,
A seal member arranged at the periphery of the insertion hole in the case and extending over the entire circumference of the pole column;
It is made of a material harder than the seal member, and has an interposed member interposed between the case and the flange of the electrode terminal in a shape extending around the seal member,
In the direction in which the fastening member is fastened, the portion where the protruding portion is in contact with the case overlaps the entire outer edge of the portion where the seal member is disposed, and the interposed member is in the case. A power storage device that overlaps at least a part of a contact portion . The power storage device according to claim 1, wherein the flange portion is formed in a stepped cylindrical shape.   The flange portion includes a first region formed in a step shape in which an inner portion near the insertion portion protrudes to an outer surface side of the case from an outer portion far from the insertion portion, and an inner portion close to the insertion portion is inserted. A second region that is not formed in a stepped shape that protrudes to the outer surface side of the case from an outer portion far from the portion,
  The power storage device according to claim 1, wherein the first region is disposed closer to the welded portion than the second region.   The flange portion has a cylindrical shape in which an inner portion close to the insertion portion protrudes to the outer surface side of the case from an outer portion far from the insertion portion, and starts from an outer peripheral surface of the protruding portion protruding to the outer surface side of the case. The power storage device according to claim 1, further comprising a plurality of wall portions extending in a radial direction of the insertion portion.   The flange portion has a cylindrical shape in which an inner portion close to the insertion portion protrudes to the outer surface side of the case from an outer portion far from the insertion portion, and an outer edge of the flange portion from a protrusion portion protruding to the outer surface side of the case The power storage device according to claim 1, wherein the thickness in the axial direction becomes thinner as it goes toward.   The power storage device according to any one of claims 1 to 5, wherein the power storage device is a secondary battery.