JP6677107B2 - Power storage device - Google Patents

Description

  The present invention relates to a power storage device having an insulating cover.

  2. Description of the Related Art A vehicle such as an EV (Electric Vehicle) and a PHV (Plug in Hybrid) is equipped with a secondary battery as a power storage device that stores power supplied to a traveling motor. Generally, a secondary battery includes a case for housing an electrode assembly, and the electrode assembly is housed in the case. Then, power is taken out of the secondary battery through electrode terminals connected to the positive electrode and the negative electrode of the electrode assembly via a conductive member.

Examples of the electrode assembly include a stacked electrode assembly in which a plurality of positive electrodes and a plurality of negative electrodes are stacked with a separator interposed therebetween.
In general, a metal case made of aluminum or the like, which has excellent durability, is often used for a case of a secondary battery. An insulating film is disposed between the electrode assembly and the case to insulate the metal case from the electrode assembly.

  In the power storage device disclosed in Patent Literature 1, the positive electrode and the negative electrode current collecting member (conductive member) are connected to the current collecting group (tab group) with the positive electrode current collecting member (conductive member) so as to face the electrode assembly. A current collecting member and a negative electrode current collecting member are provided. In the case, an insulating cover having a U-shaped cross section is provided between the positive electrode current collecting member and the negative electrode current collecting member and the terminal wall (lid member) of the case, and separates the opposing surface from the lid member. ing.

Re-publication WO2013 / 157433

  By the way, as one of the methods for manufacturing a secondary battery, a lid terminal assembly in which an electrode terminal is fixed to a lid member, and a conductive member is joined to the electrode terminal, and the lid member, the electrode terminal and the conductive member are unitized. There is a method of assembling in advance. In this method, after joining the conductive member of the lid terminal assembly and the tab group of the electrode assembly, the electrode assembly is inserted into the case member, and the lid member is fixed to the case member.

  In this method, after joining the electrode terminals to the conductive member, it is impossible to mount an insulating cover having a U-shaped cross section as disclosed in Patent Document 1, and to insulate the outermost layer of the tab group from the case. In addition, the insulating film must be disposed not only in the active material layer of the electrode assembly but also in the position of the tab group. Therefore, in a secondary battery manufactured using the lid terminal assembly, in order to insulate the outermost layer of the tab group from the case, an insulating cover having a U-shaped cross section is attached before joining the electrode terminal to the conductive member. Therefore, reduction of the assembly process is required.

  An object of the present invention is to provide a power storage device that can easily insulate a tab group and a case.

  The power storage device for solving the above problems has an electrode assembly in which sheet-like positive and negative electrodes are alternately stacked in an insulated state, and a tab having a shape protruding from a part of one side of the electrode. A tab group stacked with the same polarity, a case member for accommodating the electrode assembly and the tab group, and a case having a lid member for closing an opening of the case member; and a case fixed to the lid member, A pair of electrode terminals each having a base protruding from the lid member toward the electrode assembly; and a pair of conductive members disposed between the lid member and an end face of the electrode assembly facing the lid member. A holder that insulates the lid member from the base of the electrode terminal; and a first wall insulation that insulates one of the conductive member and the lid member when a direction in which the electrodes are stacked is a stacking direction. Part, the stacking direction of the tab group of both poles A first insulating cover having a first tab insulating portion for insulating one end side and the case member, and a first locking claw for locking to the one conductive member or the holder; and the other conductive member and the lid. A second wall insulating portion that insulates the member, a second tab insulating portion that insulates the other end of the tab group of both poles in the stacking direction and the case member, and a second tab that is engaged with the other conductive member or the holder. And a second insulating cover having two locking claws.

  According to this, in one of the methods for manufacturing a power storage device, an electrode terminal is fixed to a lid member, a conductive member is joined to the electrode terminal, and a lid terminal assembly is manufactured in advance, and then a tab group is formed on the conductive member. After joining and integrating the lid terminal assembly and the electrode assembly, there is a method of housing the electrode assembly in a case member.

  In this method, after the lid terminal assembly is manufactured, the first wall insulating portion of the first insulating cover is inserted between the lid member and one of the conductive members from one end side in the stacking direction, and the second insulating cover is formed. The second wall insulating portion of the cover is inserted between the lid member and the other conductive member from the other end in the stacking direction. Then, the pair of insulating covers is assembled to the lid terminal assembly. And, by the engagement of the engagement claws with the conductive member or the holder, it is possible to prevent the two insulating covers from moving in the direction away from each other along the stacking direction in the electrode assembly.

  In the power storage device, the lid member and one conductive member are insulated by the first wall insulating portion, and the lid member and the other conductive member are insulated by the second wall insulating portion. Further, the outermost layer on one end side in the stacking direction of the tab group of both poles is insulated from the case member by the first tab insulating portion, and the outermost layer on the other end side in the stacking direction of the tab group of both poles is connected to the case member by the second tab insulating portion. Insulated. Therefore, even in the case of a power storage device manufactured by mounting an insulating cover after assembling the lid terminal assembly, the outermost layer of the tab group can be insulated from the case member without increasing the number of steps for the insulation. Can be insulated.

  Further, regarding the power storage device, when a direction in which the pair of conductive members are arranged is a juxtaposed direction, and a facing surface of the conductive member facing the juxtaposed direction is a distal end surface of each conductive member, the first insulating cover is And a contact surface that contacts the distal end surface of one of the conductive members, and the second insulating cover may include a contact surface that contacts the distal end surface of the other conductive member.

  According to this, the conductive member is fixed to the lid member and cannot be moved. By bringing the contact surface of each insulating cover into contact with the front end surface of the conductive member, it is possible to suppress the movement of each insulating cover in the juxtaposition direction. The movement of each insulating cover in the stacking direction can be suppressed by locking the locking claws. Therefore, the movement of each insulating cover in both the laminating direction and the juxtaposed direction can be suppressed by the contact between the distal end surface of the conductive member and the contact surface of the insulating cover and the locking of the locking claw.

  In the power storage device, the first insulating cover includes a first terminal insulating portion that insulates the base joined to one conductive member from the electrode assembly, and the second insulating cover includes the other terminal. A second terminal insulating part for insulating the base joined to the conductive member from the electrode assembly may be provided.

  According to this, by attaching the first insulating cover to the electrode assembly, not only the one conductive member and the tab group of both electrodes but also the one electrode terminal can be insulated from the electrode assembly. Further, by attaching the second insulating cover to the electrode assembly, not only the other conductive member and the tab group of both electrodes but also the other electrode terminal can be insulated from the electrode assembly.

  The power storage device is a secondary battery.

  According to the present invention, the tab group and the case can be easily insulated.

FIG. 2 is an exploded perspective view showing the secondary battery of the embodiment. FIG. 1 is a perspective view showing a secondary battery according to an embodiment. The perspective view showing the state where the 1st insulating cover and the 2nd insulating cover were assembled. The perspective view which shows a lid terminal assembly. The top view which shows a lid terminal assembly. The perspective view which mounts a 1st insulating cover and a 2nd insulating cover to a lid terminal assembly. FIG. 7 is a sectional view taken along line 7-7 of FIG. 2. The top view which shows another example.

Hereinafter, an embodiment in which a power storage device is embodied as a secondary battery will be described with reference to FIGS. 1 to 7.
As shown in FIG. 1 or 2, the secondary battery 10 as a power storage device includes a case 11, and the case 11 houses an electrode assembly 12. The case 11 includes a square box-shaped case member 14 and a rectangular flat lid member 15 for closing the opening 14a of the case member 14. Note that the secondary battery 10 of the present embodiment is a lithium ion battery.

  The electrode assembly 12 includes a plurality of sheet-like positive electrodes 21 and a plurality of sheet-like negative electrodes 31. The positive electrode 21 and the negative electrode 31 have different polarities. Although not shown in detail, the positive electrode 21 has a positive metal foil (aluminum foil in this embodiment) and positive electrode active material layers present on both surfaces of the positive metal foil. The negative electrode 31 has a negative electrode metal foil (a copper foil in the present embodiment) and negative electrode active material layers present on both surfaces of the negative electrode metal foil. The electrode assembly 12 is of a laminated type in which a plurality of positive electrodes 21 and a plurality of negative electrodes 31 are layered with a separator 24 interposed therebetween for insulating them. The direction in which the positive electrode 21 and the negative electrode 31 are stacked is defined as the stacking direction of the electrode assembly 12.

  The positive electrode 21 has a tab 25 having a shape protruding from a part of one side 21 a of the positive electrode 21. The negative electrode 31 has a tab 35 having a shape protruding from a part of one side 31 a of the negative electrode 31. The plurality of positive electrode tabs 25 and the plurality of negative electrode tabs 35 are provided at positions where the positive electrode tab 25 and the negative electrode tab 35 do not overlap in a state where the positive electrode electrode 21 and the negative electrode electrode 31 are stacked. .

  The electrode assembly 12 includes a tab-side end surface 12b as an end surface. The tab-side end face 12b is formed by collecting one side 21a of the positive electrode 21, one side 31a of the negative electrode 31, and one side of the separator 24. The respective positive electrodes 21 constituting the electrode assembly 12 are stacked such that the respective tabs 25 are arranged in a row along the stacking direction. Similarly, the negative electrodes 31 constituting the electrode assembly 12 are stacked such that the tabs 35 are arranged in rows along the stacking direction.

  The secondary battery 10 has a positive electrode tab group 36 protruding from the tab side end surface 12b. The tab group 36 gathers all the positive electrode tabs 25 to one end side of the electrode assembly 12 in the laminating direction. It is configured. In addition, the secondary battery 10 has a negative electrode tab group 36 protruding from the tab side end surface 12b, and the tab group 36 gathers all the negative electrode tabs 35 to one end side of the electrode assembly 12 in the stacking direction. , Stacked.

  In the secondary battery 10, the inner surface 15 d of the lid member 15 of the case 11 faces the tab groups 36 accommodated in the case 11 and the tab-side end surface 12 b of the electrode assembly 12. The direction connecting the inner surface 15d of the lid member 15 and the tab-side end surface 12b of the electrode assembly 12 at the shortest distance is defined as the facing direction Z.

  A positive electrode conductive member 51 for electrically connecting the electrode assembly 12 and a positive electrode terminal structure 16 described later is joined to the positive electrode tab group 36. Further, a negative electrode conductive member 52 for electrically connecting the electrode assembly 12 and a negative electrode terminal structure 17 described below is joined to the negative electrode tab group 36. A positive electrode conductive member 51 and a negative electrode conductive member 52 are arranged between the inner surface 15d of the lid member 15 and the tab side end surface 12b of the electrode assembly 12. The direction in which the positive electrode conductive member 51 and the negative electrode conductive member 52 are juxtaposed along the tab side end surface 12b is referred to as juxtaposition direction X.

  The positive electrode conductive member 51 includes a plate-shaped electrode joining portion 51a joined to the tab group 36 at one end in the longitudinal direction. In addition, the positive electrode conductive member 51 includes a flat plate-shaped terminal connecting portion 51b connected to a positive electrode extraction terminal 60 described later on the other end side in the longitudinal direction, and the electrode connecting portion 51a and the terminal connecting portion 51b are continuously formed in the longitudinal direction. I have.

  The negative electrode conductive member 52 includes a flat plate-shaped electrode bonding portion 52a electrically connected to the tab group 36 at one end in the longitudinal direction. Further, the negative electrode conductive member 52 includes a terminal connection portion 52b electrically connected to a negative electrode lead terminal 61 described later on the other end side in the longitudinal direction, and the electrode connection portion 52a and the terminal connection portion 52b are continuously formed in the longitudinal direction. I have. The electrode joining portion 52a has a shape in which the dimension along the shorter direction of the negative electrode conductive member 52 is smaller than that of the terminal connecting portion 52b, and is smaller than the size along the shorter direction of the lid member 15.

  Next, the positive terminal structure 16 and the negative terminal structure 17 will be described. Since the positive electrode terminal structure 16 and the negative electrode terminal structure 17 have basically the same configuration except for a current cutoff mechanism, common members will be described using the same member numbers.

  First, the configuration of the lid member 15 for providing the positive electrode terminal structure 16 and the negative electrode terminal structure 17 will be described. The cover member 15 has an outer surface 15c facing the outside of the case 11 and an inner surface 15d facing the inside of the case 11, and the thickness direction is defined as a direction connecting the outer surface 15c and the inner surface 15d at the shortest distance in the cover member 15. The lid member 15 has insertion holes 15e at both ends in the longitudinal direction. Each insertion hole 15e penetrates the lid member 15 in the thickness direction.

  Each of the positive electrode terminal structure 16 and the negative electrode terminal structure 17 includes an outer insulating member 57 disposed on the outer surface 15 c of the lid member 15. The outer insulating member 57 insulates the external connection terminal 66 and the positive electrode lead terminal 60 of the positive electrode from the lid member 15, and insulates the external connection terminal 66 and the negative electrode lead terminal 61 of the negative electrode from the lid member 15. The outer insulating member 57 is made of a synthetic resin. The outer insulating member 57 has a rectangular shape when viewed from the outer surface 15c of the lid member 15. The direction connecting the front surface 57c and the back surface 57a of the outer insulating member 57 is defined as a thickness direction.

  The outer insulating member 57 includes a detent part 58 near one end in the longitudinal direction. The detent portion 58 has a rectangular shape recessed from the front surface 57c to the rear surface 57a. The outer insulating member 57 has an insertion hole 57d near the other end in the longitudinal direction. The insertion hole 57d is located at a position coinciding with the insertion hole 15e of the lid member 15.

  The positive terminal structure 16 and the negative terminal structure 17 each include an external connection terminal 66 disposed outside the lid member 15, and the external connection terminal 66 electrically connects the secondary batteries 10 outside the lid member 15. Bus bar to be fixed. The external connection terminal 66 is made of metal. The external connection terminal 66 has a prismatic bolt head 67, a shaft 68 protruding from one end surface of the bolt head 67 along the axial direction of the external connection terminal 66, and another end surface of the bolt head 67. And an engagement projection 69 having a shape protruding from the projection. A bus bar fastening nut can be screwed into the shaft portion 68.

  The engaging projection 69 has a square shape when viewed in the axial direction. The square shape formed by connecting the four outer surfaces of the engagement projection 69 is similar to the square shape formed by connecting the four inner surfaces of the rotation preventing portion 58 of the outer insulating member 57. The engagement projection 69 of the external connection terminal 66 is inserted into the rotation preventing portion 58 of the outer insulating member 57. The four outer surfaces of the engaging projection 69 contact and lock the four inner surfaces of the rotation preventing portion 58. Due to this contact, the movement of the external connection terminal 66 in the direction along the surface 57c of the outer insulating member 57 is suppressed, and in particular, the rotation on the surface 57c of the outer insulating member 57 is suppressed.

  The positive electrode terminal structure 16 includes a positive electrode lead terminal 60 serving as an electrode terminal electrically connected to the positive electrode tab group 36 of the electrode assembly 12 via the positive electrode conductive member 51. The negative electrode terminal structure 17 includes a negative electrode lead terminal 61 as an electrode terminal electrically connected to the negative electrode tab group 36 of the electrode assembly 12 via the negative electrode conductive member 52.

  The positive electrode lead-out terminal 60 includes a connection shaft portion 60a that is electrically connected to a terminal connection member 44 described later, a base 60b that is electrically connected to the terminal connection portion 51b of the positive electrode conductive member 51, and a protrusion from the base 60b. And a caulking portion (not shown) formed continuously in the axial direction. The terminal connecting member 44 includes a connecting piece 46 connected to the external connection terminal 66 at one end in the longitudinal direction, and a fixing piece 47 at the other end in the longitudinal direction. The terminal connection member 44 includes a through hole 46a penetrating the connection piece 46 in the thickness direction, and the shaft portion 68 of the external connection terminal 66 is inserted into the through hole 46a. In addition, the terminal connection member 44 includes an insertion hole 47a that penetrates the fixing piece 47 in the thickness direction.

  The base 60b of the positive electrode lead-out terminal 60 is disposed so as to protrude into the case 11 from the inner surface 15d of the lid member 15, and the connecting shaft 60a is provided with an insertion hole 40a of the holder 40, an insertion hole 15e of the lid member 15, It penetrates through the insertion hole 57d of the outer insulating member 57 and the insertion hole 47a of the terminal connection member 44. The caulking portion penetrates the positive electrode conductive member 51 and protrudes toward the electrode assembly 12. The caulked portion is caulked and is in contact with the terminal connection portion 51b.

  The positive electrode terminal structure 16 has an O-ring 73, through which the connecting shaft portion 60a of the positive electrode lead-out terminal 60 is inserted and supported by the base 60b. The positive electrode terminal structure 16 has the above-described holder 40 into which the connecting shaft portion 60a is inserted. The dimension of the holder 40 along the lateral direction of the lid member 15 is larger than the dimension of the positive electrode conductive member 51 also along the lateral direction. For this reason, the holder 40 protrudes from the positive electrode conductive member 51 along the lateral direction of the lid member 15.

  An O-ring 73 supported by the terminal connection portion 51b is disposed inside the holder 40. The connecting shaft portion 60a penetrating the insertion hole 47a of the terminal connecting member 44 and the caulking portion penetrating the terminal connecting portion 51b are caulked in the axial direction, so that the positive electrode conductive member is formed by the connecting shaft portion 60a and the caulking portion. The fixing piece 47 of the holder 51, the lid 40, the outer insulating member 57, and the terminal connecting member 44 is sandwiched. By this sandwiching, the positive electrode lead-out terminal 60 is fixed to the lid member 15. The O-ring 73 is in close contact with the inner surface 15 d of the cover member 15 around the insertion hole 15 e and seals the insertion hole 15 e of the cover member 15.

  As shown in FIG. 2, the distal end of the connecting shaft 60 a of the positive electrode lead-out terminal 60 is locked on the surface of the fixing piece 47 of the terminal connecting member 44, and the positive electrode lead-out terminal 60 is connected to the terminal by this locking. The connection member 44 is electrically connected. The base 60b of the positive electrode lead terminal 60 contacts the terminal connection part 51b of the positive electrode conductive member 51, and the positive electrode lead terminal 60 and the positive electrode conductive member 51 are electrically connected by this contact.

  As shown in FIG. 1, in the negative electrode terminal structure 17, the negative electrode lead-out terminal 61 is electrically connected to the connection shaft portion 62 electrically connected to the negative terminal connection member 44 and the terminal connection portion 52 b of the negative electrode conductive member 52. And a base 63 which is connected in a continuous manner in the axial direction. The connection shaft portion 62 of the negative electrode lead-out terminal 61 is inserted through the insertion hole 40 a of the holder 40, the insertion hole 15 e of the lid member 15, the insertion hole 57 d of the outer insulating member 57, and the insertion hole 47 a of the terminal connection member 44.

  The base 63 of the negative electrode lead-out terminal 61 has a square plate shape. The base 63 is larger in size than the base 60b on the positive electrode side. The outer shape of the base 63 is a square shape when the negative electrode lead-out terminal 61 is viewed from the axial direction. The negative electrode terminal structure 17 has an O-ring 73, through which the connecting shaft 62 is inserted and supported by the base 63. The negative electrode terminal structure 17 has a cylindrical holder 40 into which the connection shaft 62 is inserted. An O-ring 73 supported by the base 63 is arranged inside the holder 40. The holder 40 is interposed between the lid member 15 and the base 63 of the negative electrode lead-out terminal 61, regulates contact between the lid member 15 and the base 63, and insulates the lid member 15 from the negative electrode lead-out terminal 61. I do. The negative electrode holder 40 covers the outer peripheral surface of the base 63 and insulates the negative electrode lead-out terminal 61 from the case 11.

  As shown in FIG. 2, in the negative electrode terminal structure 17, the distal end portion of the connection shaft portion 62 that penetrates the insertion hole 47 a of the terminal connection member 44 is caulked in the axial direction, so that the connection shaft portion 62 and the base portion 63 form. , Holder 40, lid member 15, outer insulating member 57, and terminal connecting member 44 are sandwiched. By this sandwiching, the negative electrode lead-out terminal 61 is fixed to the lid member 15. The O-ring 73 is in close contact with the inner surface 15 d of the cover member 15 around the insertion hole 15 e and seals the insertion hole 15 e of the cover member 15.

  Further, the distal end of the connecting shaft portion 62 of the negative electrode lead-out terminal 61 is locked to the surface of the fixing piece 47 of the terminal connecting member 44, and this locking allows the negative electrode lead-out terminal 61 and the terminal connecting member 44 to be electrically connected. It is connected.

  The secondary battery 10 includes a current cutoff mechanism 80 integrated with the negative electrode lead-out terminal 61 which is one electrode terminal. The current interrupting mechanism 80 is disposed inside the case 11. When the internal pressure of the case 11 reaches a predetermined set pressure, the current interrupting mechanism 80 electrically connects the electrode assembly 12 and the negative electrode lead-out terminal 61. Cut off the current in the path.

Next, the insulating cover in the case 11 will be described.
As shown in FIG. 7, the secondary battery 10 includes a first insulating cover 81 mounted from one end of the electrode assembly 12 in the stacking direction, and a second insulating cover 81 mounted from the other end of the electrode assembly 12 in the stacking direction. And an insulating cover 91. In each of the insulating covers 81 and 91, a direction along the direction X in which the positive electrode conductive members 51 and the negative electrode conductive members 52 are arranged is defined as a longitudinal direction, and a direction along the outer surface of each of the insulating covers 81 and 91 and orthogonal to the longitudinal direction is defined. Short direction.

  As shown in FIG. 1 or FIG. 5, the first insulating cover 81 includes a first wall insulating portion 82. The first wall insulating portion 82 of the first insulating cover 81 is interposed between the electrode joining portion 51a of the positive electrode conductive member 51 as one conductive member and the cover member 15 to insulate both. When viewed from the outer surface 15c of the lid member 15, the first wall insulating portion 82 has a shape that covers substantially the entire surface of the electrode joining portion 51a. The first insulating cover 81 includes a first tab insulating portion 83 having a shape protruding from one long edge of the first wall insulating portion 82 toward the electrode assembly 12. The first tab insulating portion 83 has an elongated plate shape. The first tab insulating portion 83 of the first insulating cover 81 has a dimension capable of covering the tab group 36 of both electrodes from the outside in the stacking direction.

  The first tab insulating portion 83 of the first insulating cover 81 is disposed at one end of the electrode assembly 12 in the stacking direction, and covers one end of the tab group 36 of both electrodes in the stacking direction from outside. The first tab insulating portion 83 is disposed between the outermost layer tabs 25 and 35 located at one end side in the stacking direction of the tab group 36 of both poles in the stacking direction, and a portion of the case member 14 opposed to one end of the tab group 36. To insulate the tab group 36 of both poles and the case member 14 from each other.

  The first insulating cover 81 includes an integral connecting portion 84 at one end in the short direction. The first insulating cover 81 includes a first terminal insulating portion 85 integrated with the connecting portion 84. The connecting portion 84 separates the first wall insulating portion 82 and the first terminal insulating portion 85 in the facing direction Z in a side view along the longitudinal direction.

  Therefore, the first wall insulating portion 82 and the first terminal insulating portion 85 are separated in the facing direction Z in a side view along the longitudinal direction. The first terminal insulating portion 85 has a quadrangular shape in plan view when viewed from the outer surface 15c of the lid member 15. The planar size of the first terminal insulating portion 85 is larger than the planar size of the crimped portion of the positive electrode lead-out terminal 60, and the entire crimped portion can be covered from the electrode assembly 12 side.

  The first terminal insulating portion 85 includes a ridge portion 85c at portions along three sides. In a side view along the longitudinal direction, the first wall insulating portion 82 and the ridge portion 85c are located at positions facing each other in the facing direction Z. Therefore, the first insulating cover 81 includes the first gap 85d between the first wall insulating portion 82 and the first terminal insulating portion 85 which face each other in a side view.

  The dimension of the first gap 85d along the facing direction Z is larger than the thickness of the positive electrode conductive member 51, and the positive electrode conductive member 51 is inserted into the first gap 85d. The first insulating cover 81 includes a first locking claw 85 a protruding from the ridge 85 c of the first terminal insulating portion 85. The first locking claw 85a of the first terminal insulating portion 85 projects from the ridge portion 85c toward the first wall insulating portion 82 from the first terminal insulating portion 85 in a side view. The dimension between the connecting portion 84 of the first insulating cover 81 along the transverse direction and the opposing surface of the first locking claw 85a is longer than the dimension of the holder 40 along the transverse direction. When the terminal connection portion 51b enters the first gap 85d, the connection portion 84 contacts one of the edges of the holder 40, and the first locking claw contacts the other edge. 85a is locked.

  As shown in FIG. 4, the first insulating cover 81 includes a first restricting portion 87 protruding in a lateral direction from an inner surface of the first tab insulating portion 83. The first restricting portion 87 has a rectangular shape when viewed from the outer surface of the lid member 15. In the first restricting portion 87, a contact surface 87 a extending in the lateral direction of the first insulating cover 81 is in contact with the front end surface 51 c of the positive electrode conductive member 51. The tip end surface 51c of the positive electrode conductive member 51 is an end surface of the electrode bonding portion 51a facing the electrode bonding portion 52a of the negative electrode conductive member 52 in the juxtaposition direction X, and is linear in the stacking direction of the electrode assembly 12. It is a surface extending in a shape.

  As shown in FIG. 1, FIG. 3, or FIG. 5, the second insulating cover 91 includes a second wall insulating portion 92. The second wall insulating portion 92 of the second insulating cover 91 is interposed between the electrode joining portion 52a and the lid member 15 to insulate both. As viewed from the outer surface 15c of the lid member 15, the second wall insulating portion 92 has a shape that covers substantially the entire surface of the electrode joining portion 52a. The second insulating cover 91 includes a second tab insulating portion 93 having a shape protruding from one long edge of the second wall insulating portion 92 toward the electrode assembly 12. The second tab insulating portion 93 is in the shape of an elongated plate. The second tab insulating portion 93 of the second insulating cover 91 has a size capable of covering the tab group 36 of both poles.

  The second tab insulating portion 93 of the second insulating cover 91 is disposed at the other end of the electrode assembly 12 in the stacking direction, and covers the tab group 36 of both electrodes from the other end in the stacking direction. The second tab insulating portion 93 includes tabs 25 and 35 of the outer layer located on the other end side in the stacking direction of the tab group 36 of both poles in the stacking direction, and a portion facing the other end of the tab group 36 in the case member 14. To insulate the tab group 36 of both poles and the case member 14 from each other.

  The second insulating cover 91 includes an integral connecting portion 94 at one end in the longitudinal direction and one end in the short direction of the second wall insulating portion 92. The second insulating cover 91 includes a second terminal insulating portion 96 integrated with the connecting portion 94.

  The second terminal insulating portion 96 has a quadrangular shape in plan view when viewed from the outer surface 15c of the lid member 15. The planar size of the second terminal insulating portion 96 is substantially the same as the planar size of the base 63 of the negative electrode lead-out terminal 61 and the current interrupting mechanism 80, and the current interrupting mechanism 80 can be covered from the electrode assembly 12 side. The second terminal insulating portion 96 includes a ridge 96c along three sides.

  The second insulating cover 91 includes a second gap 96e between the second wall insulating portion 92 and the ridge 96c in the facing direction Z. The dimension of the second gap 96e along the facing direction Z is larger than the thickness of the negative electrode conductive member 52, and the negative electrode joining portion 52a is inserted into the second gap 96e.

  In the second terminal insulating portion 96, the connecting portion 94 is located at one end of the ridge portion 96c, and the second engaging claw 96a is located at the other end of the second insulating cover 91 in the short-side direction of the second insulating cover 91. Exists. The second locking claw 96a of the second terminal insulating portion 96 protrudes from the ridge portion 96c toward the second wall insulating portion 92 from the second terminal insulating portion 96 in a side view. The dimension between the connecting portion 94 of the second insulating cover 91 along the transverse direction and the opposing surface of the second locking claw 96a is slightly longer than the dimension of the terminal connecting portion 52b along the transverse direction. Then, in a state where the electrode bonding portion 52a enters the second gap 96e, the connecting portion 94 abuts on one of the edges of the terminal connecting portion 52b facing the short direction of the second insulating cover 91, and A second locking claw 96a is locked to the other edge.

  The second insulating cover 91 includes a second restricting portion 97 protruding in a lateral direction from an inner surface of the second tab insulating portion 93. The second restricting portion 97 has a rectangular shape when viewed from the outer surface of the lid member 15. The contact surface 97 a of the second regulating portion 97, which extends in the lateral direction of the second insulating cover 91, contacts the distal end surface 52 c of the negative electrode conductive member 52. The tip end face 52c of the negative electrode conductive member 52 is an end face of the electrode bonding part 52a facing the electrode bonding part 51a of the positive electrode conductive member 51 in the juxtaposition direction X, and is linear in the stacking direction of the electrode assembly 12. It is a surface extending in a shape.

Next, a method of manufacturing the secondary battery 10 will be described together with its operation.
It is assumed that the negative electrode lead-out terminal 61, the current interrupting mechanism 80, and the negative electrode conductive member 52 are integrated in advance.

  First, as shown in FIG. 1, the outer insulating member 57 is arranged on the outer surface 15c of the lid member 15. The engaging projection 69 of the external connection terminal 66 is inserted into the rotation preventing portion 58 of the outer insulating member 57. Next, the shaft portion 68 of the external connection terminal 66 is inserted into the through hole 46a of the terminal connection member 44.

  Next, on the positive electrode side, the O-ring 73 and the holder 40 are arranged on the inner surface 15d side of the lid member 15. Then, the connecting shaft portion 62 of the positive electrode lead-out terminal 60 is inserted into the insertion hole 40a of the holder 40, the O-ring 73, the insertion hole 15e of the lid member 15, the insertion hole 57d of the outer insulating member 57, and the insertion hole 47a of the terminal connection member 44. Insert Then, by the caulking portion of the positive electrode lead-out terminal 60 and the caulking of the connecting shaft portion 60a, the positive electrode conductive member 51, the holder 40, the O-ring 73, the lid member 15 are provided between the caulking portion and the end of the connecting shaft portion 60a. The outer insulating member 57 and the terminal connecting member 44 are integrated.

  On the negative electrode side, the O-ring 73 and the holder 40 are arranged on the inner surface 15d side of the lid member 15, and the insertion hole 40a of the holder 40, the O-ring 73, the insertion hole 15e of the lid member 15, the insertion hole 57d of the outer insulating member 57, and The connection shaft 62 of the negative electrode lead-out terminal 61 is inserted into the insertion hole 47 a of the terminal connection member 44. Then, the holder 40, the O-ring 73, the lid member 15, the outer insulating member 57, and the terminal connecting member 44 are integrally formed between the base 63 and the distal end of the connecting shaft 62 by caulking the connecting shaft 62. And the current interruption mechanism 80 is also integrated.

  Then, as shown in FIG. 6, the positive electrode terminal structure 16 and the negative electrode terminal structure 17 are formed on the lid member 15, and the lid terminal assembly 20 is formed. A gap exists between the lid member 15 and the electrode joints 51a and 52a.

  The positive electrode tab group 36 of the electrode assembly 12 is joined to the electrode joining portion 51a of the positive electrode conductive member 51 by laser welding, and the negative electrode tab group 36 is joined to the electrode joining portion 52a of the negative electrode conductive member 52 by laser welding. Joined by welding. Then, the lid terminal assembly 20 and the electrode assembly 12 are integrated. Next, the tab group 36 is bent.

  Then, the first wall insulating portion 82 of the first insulating cover 81 is inserted between the lid member 15 and the electrode joining portion 51a from one end in the stacking direction, and the positive electrode conductive member 51 is inserted into the first gap 85d. As described above, the first insulating cover 81 is slid.

  On the positive electrode side, the first locking claw 85 a of the first terminal insulating portion 85 is locked to the edge of the holder 40. As a result, the first insulating cover 81 is integrally assembled with the positive electrode conductive member 51, and the electrode joining portion 51a is insulated from the lid member 15 by the first wall insulating portion 82. At the same time, one end side in the stacking direction of the tab group 36 of both electrodes is insulated from the side wall of the case 11 by the first tab insulating portion 83. Also, the first terminal insulating portion 85 insulates the swaged portion of the positive electrode lead-out terminal 60 from the electrode assembly 12 side.

  In addition, the second wall insulating portion 92 of the second insulating cover 91 is inserted between the lid member 15 and the electrode joining portion 52a from the other end in the stacking direction, and the negative electrode conductive member 52 is inserted into the second gap 96e. The second insulating cover 91 is slid so as to be inserted.

  Then, on the negative electrode side, the second locking claw 96a of the second terminal insulating portion 96 is locked to the edge of the terminal connecting portion 52b. As a result, the second insulating cover 91 is integrally assembled with the negative electrode conductive member 52, and the electrode joining portion 52 a is insulated from the lid member 15 by the second wall insulating portion 92. At the same time, the other end face in the stacking direction of the tab group 36 of both poles is insulated from the side wall of the case 11 by the second tab insulating part 93. Further, the second terminal insulating portion 96 insulates the current interrupting mechanism 80 from the electrode assembly 12 side.

  As a result, as shown in FIG. 7, the first insulating cover 81 and the second insulating cover 91 are assembled to the electrode assembly 12, and the electrode joints 51a and 52a are connected to the first and second wall insulating parts 82. , 92 are insulated from the lid member 15. At the same time, one end of the tab group 36 of both poles in the stacking direction is insulated from the side wall of the case 11 by the first tab insulating part 83, and the other end of the tab group 36 of both poles in the stacking direction is formed by the second tab insulating part 93. The state is insulated from the side wall.

  As shown in FIG. 5, the contact surface 87 a of the first restricting portion 87 of the first insulating cover 81 contacts the distal end surface 51 c of the positive electrode conductive member 51. Due to this contact, the movement of the first insulating cover 81 in the juxtaposition direction X is suppressed. In addition, the contact surface 97 a of the second regulating portion 97 of the second insulating cover 91 contacts the distal end surface 52 c of the negative electrode conductive member 52. Due to this contact, the movement of the second insulating cover 91 in the juxtaposition direction X is suppressed.

  After the first insulating cover 81 and the second insulating cover 91 are attached to the lid terminal assembly 20, the electrode assembly 12 is inserted into the case member 14 from the opening 14a of the case member 14. Thereafter, when the lid member 15 is joined to the open end of the case member 14, the secondary battery 10 is assembled.

According to the above embodiment, the following effects can be obtained.
(1) Regarding the manufacture of the secondary battery 10, the lid terminal assembly 20 is manufactured in advance, and the tab groups 36 are joined to the electrode joining portions 51 a and 52 a of the lid terminal assembly 20, respectively. There is a method of manufacturing the secondary battery 10 by housing the electrode assembly 12 in the case member 14 in a state where the components are integrated. In this manufacturing method, the first insulating cover 81 and the second insulating cover 91 are provided between the lid member 15 and the electrode joints 51a, 52a after the lid terminal assembly 20 is manufactured. And inserted.

  For this reason, in the secondary battery 10, with respect to the tab group 36 of both electrodes of the electrode assembly 12, one end side in the stacking direction can be insulated from the case member 14 by the first tab insulating portion 83 of the first insulating cover 81. The other end in the direction can be insulated from the case member 14 by the second tab insulating portion 93 of the second insulating cover 91. Therefore, even in the secondary battery 10 manufactured by attaching the insulating covers 81 and 91 to the lid terminal assembly 20, the tab group 36 of both electrodes can be easily insulated from the case 11 from both ends in the stacking direction. . Therefore, the tab group 36 of both poles can be insulated from the case member 14 only by attaching the insulating covers 81 and 91, so that the number of steps for the insulation need not be increased.

  (2) The first insulating cover 81 includes a first locking claw 85a that locks to the holder 40, and the second insulating cover 91 locks to the terminal connection portion 52b of the negative electrode conductive member 52. A stop claw 96a is provided. The holder 40 and the negative electrode conductive member 52 are assembled to the lid terminal assembly 20 and are fixed to the lid member 15. By locking the locking claws 85a and 96a to the fixed holder 40 and the negative electrode conductive member 52, the movement of each of the insulating covers 81 and 91 in the direction opposite to the insertion direction can be suppressed.

  (3) The first insulating cover 81 has a contact surface 87 a that contacts the distal end surface 51 c of the positive electrode conductive member 51, and the second insulating cover 91 has a contact surface that contacts the distal end surface 52 c of the negative electrode conductive member 52. The surface 97a is provided. The contact between the contact surfaces 87a, 97a and the tip surfaces 51c, 52c can suppress the movement of the insulating covers 81, 91 in the juxtaposition direction X. The movement of the insulating covers 81 and 91 in the stacking direction can be suppressed by the locking of the locking claws 85a and 96a. Accordingly, the stacking direction and the juxtaposition are provided by the contact between the distal end surfaces 51c, 52c of the conductive members 51, 52 and the contact surfaces 87a, 97a of the insulating covers 81, 91 and the locking of the locking claws 85a, 96a. The movement of each of the insulating covers 81 and 91 in both directions can be suppressed, and the insulating state can be maintained.

  (4) When the first insulating cover 81 is attached to the electrode assembly 12, the swaged portion of the positive electrode lead-out terminal 60 can be insulated from the electrode assembly 12 by the first terminal insulating portion 85. When the second insulating cover 91 is attached to the electrode assembly 12, the current interruption mechanism 80 including the negative electrode lead-out terminal 61 can be insulated from the electrode assembly 12 by the second terminal insulating portion 96. Therefore, by mounting the insulating covers 81 and 91, not only the conductive members 51 and 52 and the tab group 36 but also the lead terminals 60 and 61 can be insulated from the electrode assembly 12.

  (5) Each of the wall insulating portions 82 and 92 of each of the insulating covers 81 and 91 has a size that insulates only the electrode joining portions 51a and 52a from the lid member 15. For example, the material cost of the insulating covers 81 and 91 can be reduced as compared with the case where each of the wall insulating portions 82 and 92 extends in the entire longitudinal direction of each of the insulating covers 81 and 91.

The above embodiment may be modified as follows.
As shown in FIG. 8, the first locking claw 85 a of the first insulating cover 81 may be locked to the terminal connection portion 51 b of the positive electrode conductive member 51. Further, the second locking claws 96 a of the second insulating cover 91 may be locked to the holder 40.

In the first insulating cover 81, a locking claw that locks to the positive electrode conductive member 51 may be provided in addition to the first locking claw 85a that locks to the holder 40.
In the second insulating cover 91, a locking claw that locks to the holder 40 may be provided in addition to the second locking claw 96a that locks to the negative electrode conductive member 52.

The first terminal insulating portion 85 of the first insulating cover 81 may not be provided, and the second terminal insulating portion 96 of the second insulating cover 91 may not be provided.
The contact surface 87a of the first insulating cover 81 may not be provided, and the contact surface 97a of the second insulating cover 91 may not be provided.

  The electrode terminals need not be connected to the external connection terminals 66 via the terminal connection members 44 like the positive electrode extraction terminals 60 and the negative electrode extraction terminals 61, and may be connected to the positive electrode conductive members 51 and the negative electrode conductive members 52. It may be directly connected.

The power storage device can also be applied to a secondary battery having the current cutoff mechanism 80 integrated with the positive electrode extraction terminal 60.
The power storage device can also be applied to a secondary battery that does not include the current cutoff mechanism 80. In this case, the second insulating portion covers the bases of the bipolar electrode terminals from the electrode assembly 12 side.

  The electrode terminals need not be connected to the external connection terminals 66 via the terminal connection members 44 like the positive electrode extraction terminals 60 and the negative electrode extraction terminals 61, and may be connected to the positive electrode conductive members 51 and the negative electrode conductive members 52. It may be directly connected.

The power storage device can be applied to a power storage device other than a secondary battery, such as a capacitor.
The positive electrode 21 and the negative electrode 31 may have a structure in which an active material layer exists on one surface of a metal foil.

  The secondary battery 10 may be a lithium ion secondary battery or another secondary battery. In short, any material may be used as long as ions move between the positive electrode active material and the negative electrode active material and transfer charges.

Next, technical ideas that can be grasped from the above embodiment and other examples will be additionally described below.
(1) The electrode terminal is fixed to the lid member, the conductive member is bonded to the base of the electrode terminal, and the lid terminal assembly 20 is manufactured. Then, the tab group is bonded to the conductive member. And a power storage device in which the first insulating cover and the second insulating cover are mounted on the lid terminal assembly after the lid terminal assembly and the electrode assembly are integrated.

  DESCRIPTION OF SYMBOLS 10 ... Rechargeable battery as a power storage device, 11 ... Case, 12 ... Electrode assembly, 12b ... Tab side end surface as an end surface, 14 ... Case member, 14a ... Opening, 15 ... Lid member, 21 ... Positive electrode, 21a ... one side, 25, 35 ... tab, 31 ... negative electrode, 31a ... one side, 36 ... tab group, 40 ... holder, 51 ... positive electrode conductive member, 52 ... negative electrode conductive member, 51c, 52c ... tip surface, 60 ... electrode terminal Positive electrode extraction terminal, 60b, 63 ... base, 61 ... negative electrode extraction terminal as an electrode terminal, 81 ... first insulating cover, 82 ... first wall insulating part, 83 ... first tab insulating part, 85 ... first Terminal insulating portion, 85a: first locking claw, 87a, 97a: contact surface, 91: second insulating cover, 92: second wall insulating portion, 93: second tab insulating portion, 96: second terminal insulating Part, 96a: second locking claw.

Claims (4)

An electrode assembly in which sheet-like positive and negative electrodes are alternately stacked in an insulated state,
A tab group in which tabs having a shape protruding from a part of one side of the electrode are stacked with the same polarity,
A case member that houses the electrode assembly and the tab group, and a case that has a lid member that closes an opening of the case member;
A pair of electrode terminals having a base fixed to the lid member and protruding from the lid member toward the electrode assembly;
The lid member, a pair of conductive members disposed between the end surface of the electrode assembly facing the lid member,
A holder for insulating the lid member and the base of the electrode terminal,
When the direction in which the electrodes are stacked is the stacking direction,
A first wall insulating portion that insulates one conductive member and the lid member, a first tab insulating portion that insulates one end side of the tab group of both poles in the stacking direction and the case member, and the one conductive member or A first insulating cover having a first locking claw for locking to the holder;
A second wall insulating portion that insulates the other conductive member from the lid member; a second tab insulating portion that insulates the other end of the tab group of both poles in the stacking direction from the case member; and the other conductive member Or a second insulating cover having a second locking claw that is locked to the holder.   When the direction in which the pair of conductive members are arranged is a juxtaposed direction, and the opposing surface of the conductive member facing the juxtaposed direction is a tip end surface of each conductive member, the first insulating cover is one of the conductive members. 2. The power storage device according to claim 1, further comprising: a contact surface that comes into contact with the front end surface, and wherein the second insulating cover includes a contact surface that comes into contact with the front end surface of the other conductive member.   The first insulating cover includes a first terminal insulating portion that insulates the base joined to one conductive member from the electrode assembly, and the second insulating cover is joined to the other conductive member. The power storage device according to claim 1, further comprising a second terminal insulating unit that insulates the base from the electrode assembly.   The power storage device according to any one of claims 1 to 3, wherein the power storage device is a secondary battery.