JP2014143001A - Secondary battery and external terminal of secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably couple a bus bar and an external terminal without causing unsymmetrical contact even when re-coupled.SOLUTION: A secondary battery 100 has an external terminal (cathode external terminal 137), and also has a coupling member (cathode bolt 139) for coupling a bus bar 2 and an external terminal by sandwiching the same between an engaging member (nut 9) and a head part 139b attached to a shaft part 139c. The external terminal is provided, on the head part 139b side in a peripheral part 137e of an open hole 137c, with a seating part (lower-side convex part 50) abutting on the head part of the coupling member. The seating part protrudes toward the head part 139b than is a circumferential part (general part 70) surrounding the seating part, and an outer circumferential edge 50b of a contact surface 50a, abutting on the head part 139b, of the seating part (lower-side convex part 50) is located inside of an outer circumferential edge 139bb of the head part 139b, the head part 139b being in contact with the external terminal at only the contact surface 50a of the seating part.

Description

  The present invention relates to a secondary battery and an external terminal of the secondary battery. Specifically, the present invention relates to the structure of the fastening portion with the bus bar in the external terminal of the secondary battery.

  In recent years, secondary batteries such as lithium ion secondary batteries have been used in various fields such as electronic devices such as mobile phones and personal computers, vehicles such as hybrid cars and electric cars. In particular, a lithium ion secondary battery has a high energy density and is suitable for mounting in various devices.

  As such a secondary battery, the following Patent Document 1 discloses an electrode body, a battery case that houses the electrode body, an electrode body connection terminal (terminal 71 of Document 1) that penetrates the battery case, and a battery case. A secondary battery is disclosed that includes an electrode terminal member that has an external terminal (metal terminal 41 of Document 1) that is located outside and is connected to an electrode body connection terminal, and a fastening member (bolt 31 of Document 1). The external terminal of the secondary battery has a Z-shape (crank shape) composed of a fixed portion (fixed piece 41a of Reference 1), a connecting portion (connection piece 41b of Reference 1) and an external connection portion (Terminal piece 41c of Reference 1). The electrode body connection terminal is inserted into the fixed portion, and the male thread portion of the fastening member is inserted into the external connection portion.

  On the positive electrode side, the electrode body connection terminal is used to mechanically couple the electrode body connection terminal and the external terminal by caulking deformation of a portion of the electrode body connection terminal located outside the battery case, so that the battery case The external terminal is fixed to. On the other hand, on the negative electrode side, the electrode body connection terminal is used to mechanically couple the electrode body connection terminal and the external terminal by caulking deformation of the electrode body connection terminal located outside the battery case. The external terminal is fixed to.

  When a plurality of such secondary batteries are used to make an assembled battery, the external terminal on the positive side of one secondary battery (positive external terminal) and the external terminal on the negative side of another secondary battery (external negative electrode) These are connected by interposing a bus bar between them. Specifically, a fastening member (bolt) and a nut having a male screw part (shaft part), a positive external terminal (positive external terminal) and a bus bar, or a bus bar and a negative external terminal (negative external terminal) Conclude.

JP 2009-301874 A

  However, the technique described in Patent Document 1 has room for improvement in the following points. That is, as shown in FIG. 12, when the external terminal 210 and the bus bar 220 are fastened using a fastening member (bolt) 230 having a male screw part (shaft part) 231 and a nut 240, the bolt 230 is fastened with high torque. Then, the head 232 of the bolt 230 is reduced to the external terminal 210, and the recess 250 may be formed on the surface of the external terminal 210 on the head 232 side of the bolt 230. The formation of such a depression 250 in the external terminal 210 is also referred to as buckling of the fastening seating surface of the external terminal 210.

  Note that if the external terminal and the bus bar are loosely connected, the electrical resistance increases. Therefore, when the external terminal and the bus bar are fastened using bolts and nuts, the bolts are fastened with a high torque (for example, a torque of about 10 N).

  By the way, in the assembled battery in which such a fastening is performed, when a malfunction occurs in one battery constituting the assembled battery, only the malfunctioning battery may be replaced. In that case, unfasten the bolt and nut, remove the bus bar from the bolt, and replace the battery. The fastening of the bolt and nut is released for the battery in which the failure has occurred and the battery adjacent to the battery. Thereafter, the replaced battery and the battery adjacent to the battery are fastened again via the bus bar.

  Here, as described above, a recess may be formed in the external terminal during the initial fastening. Therefore, the bolt head may not fit snugly in this recess when refastened. That is, as shown in FIG. 12, the bolt 230 may deviate from the previous fastening position, and the head 232 of the bolt 230 may not fit into the recess 250. In other words, only one side of the head 232 (the right side in FIG. 12) is in contact with the outer peripheral portion 211 of the recess 250 in the external terminal 210 (a state in which one side of the head 232 rides on the outer peripheral portion 232 of the recess 250). It may become. In this specification, this state is referred to as a piece-by-piece, and a piece-of-piece is called a piece-by-piece.

  If the bolt is tightened in such a contact state, the head of the bolt cannot contact the external terminal with a sufficient area. For this reason, the external terminal and the bus bar cannot be fastened sufficiently, resulting in poor fastening.

  As a method of preventing such a contact state, it is conceivable to insert a washer on the bolt head side. However, since the external terminal is fixed to the battery case by caulking deformation of the electrode body connecting terminal, the bolt shaft cannot be removed from the external terminal. Therefore, a new washer cannot be fitted to the bolt when re-fastened. Therefore, a technique for preventing the bolt from hitting one piece without using a washer was expected. If it is not possible to prevent such contact, a battery that assumes re-fastening of the bus bar will have to refrain from tightening with high torque, which reduces the reliability of fastening between the external terminal and the bus bar. End up. Alternatively, instead of tightening with high torque on the premise that re-fastening is not performed, it is necessary to give up battery replacement for each battery unit constituting the assembled battery.

  The present invention has been made in view of the above circumstances. That is, the problem is to provide a secondary battery and an external terminal of the secondary battery that can satisfactorily fasten the bus bar and the external terminal without causing a single contact even when refastened. Objective.

  The secondary battery of the present invention, which has been made for the purpose of solving this problem, is a secondary battery that is connected to another secondary battery by a bus bar and constitutes an assembled battery, and contains an electrode body and an electrode body. Battery case, electrode body connection terminal connected to the positive electrode or negative electrode of the electrode body in the battery case, and external terminal arranged outside the battery case and electrically connected to the electrode body connection terminal , Including a shaft portion inserted through a through hole formed in the external terminal and a through hole formed in the bus bar, and a head having a diameter larger than that of the shaft portion, and is attached to the shaft portion A fastening member that fastens the bus bar and the external terminal by clamping the bus bar and the external terminal between the engaging member and the head. The external terminal is provided with a seating portion in contact with the head on the head side at the periphery of the through-hole, and the seating portion protrudes toward the head from the surrounding portion surrounding the seating portion. The outer peripheral edge of the contact surface with the head is located inside the outer peripheral edge of the head, and the head is in contact with the external terminal only by the contact surface of the seating portion.

  In the secondary battery of the present invention, the external terminal includes a seating portion protruding toward the head of the fastening member, and the outer peripheral edge of the contact surface with the head in the seating portion is more than the outer peripheral edge of the head. , Located inside. Furthermore, the head of the fastening member is not in contact with the external terminal at a place other than the contact surface of the external terminal. Therefore, when the fastening member is tightened, the surface pressure applied to the external terminal by the head due to the axial force of the fastening member is uniformly received only by the contact surface of the seating portion. Therefore, even if the contact surface of the external terminal is pushed by the head and the seating portion is uniformly compressed, the head does not decrease relative to the external terminal. That is, the external terminal is not formed with a recess along the outer periphery of the head. Therefore, it is possible to prevent the occurrence of the above-described troubles at the time of re-fastening (that is, the trouble that the head comes into contact with the external terminal when the fastening member is shifted to a fastening position different from that at the first fastening time). That is, even during re-fastening, the head of the fastening member and the external terminal can be brought into contact with each other with a sufficient area, so that good fastening can be performed. Therefore, even when the fastening is performed on the premise that the bus bar and the external terminal are re-fastened, the bus bar can be fastened with high torque without worrying about deformation of the external terminal (formation of the depression).

Here, in the secondary battery of the present invention, the external terminal is an annular head having a bottom surface that is recessed along the plate thickness direction from the contact surface of the seating portion on the inner periphery of the seating portion at the periphery of the through hole. It is desirable to have a part-side recess.
Depending on circumstances such as processing accuracy at the time of manufacturing the fastening member, the base portion of the shaft portion in the head portion of the fastening member may slightly protrude in the standing direction of the shaft portion. In that case, when the fastening member is tightened, the protruding portion of the base portion of the shaft portion may be reduced to the external terminal. Therefore, if configured as described above, such a situation can be prevented.

Further, in the secondary battery of the present invention, the external terminal includes a contact portion that contacts the bus bar on the side where the bus bar is arranged at the peripheral portion of the through hole, and the contact portion is more busbar than the surrounding portion surrounding the contact portion. The outer peripheral edge of the contact surface with the bus bar at the contact portion is located inside the outer edge of the bus bar, and the external terminal is in contact with the bus bar only at the contact surface of the contact portion. desirable.
With this configuration, when the fastening member is tightened, the surface pressure applied to the external terminal by the bus bar due to the axial force of the fastening member is uniformly received only by the contact surface of the contact portion (contact portion side contact surface). Will be. Therefore, even if the contact surface of the external terminal (contact surface on the contact portion side) is pushed by the bus bar and the contact portion is uniformly compressed, the bus bar does not decrease with respect to the external terminal. That is, the external terminal is not formed with a recess along the outer edge of the bus bar. Therefore, it is possible to prevent the occurrence of a problem that the bus bar rides on the external terminal when the bus bar is shifted to a position different from that at the time of the initial fastening at the time of re-fastening. That is, even at the time of re-fastening, the bus bar and the external terminal can be brought into contact with each other with a sufficient area, so that good fastening can be performed. Therefore, even when the fastening is performed on the premise that the bus bar and the external terminal are re-fastened, the fastening can be performed with high torque without worrying about the deformation of the external terminal due to the pushing of the bus bar.

In the secondary battery of the present invention, the external terminal is on the annular bus bar side having a bottom surface that is recessed along the plate thickness direction from the contact surface of the contact portion inside the contact portion at the periphery of the through hole. It is desirable to have a recess.
Depending on the bus bar, the peripheral edge of the through hole for inserting the shaft portion of the fastening member may be raised in a cylindrical shape toward the external terminal, for example, by burring. In this case, when the fastening member is tightened, the cylindrical portion around the through hole may be reduced to the external terminal. Therefore, if configured as described above, such a situation can be prevented.

In the secondary battery of the present invention, the external terminal includes a first terminal portion connected to the electrode body connection terminal and a second terminal portion connected to the bus bar, and the seating portion includes the second terminal portion. The contact surface of the seating portion can be configured to protrude to the head side from the surface of the second terminal portion on the head side excluding the seating portion.
With this configuration, when providing the seating portion that protrudes toward the head of the fastening member, it is not necessary to reduce the thickness of the external terminal, so that the conduction resistance is not increased and the rigidity is maintained. Can do.

In the secondary battery of the present invention, an annular head-side groove is provided on the head side of the external terminal as a peripheral portion surrounding the seating portion. It is good also as a structure located inside the outer periphery of a head side groove part while being located in the outer side of an inner periphery.
If comprised in this way, the seating part which protruded toward the head of a fastening member can be provided by simple process rather than providing with the structure mentioned above.

In the secondary battery of the present invention, the external terminal includes a first terminal portion connected to the electrode body connection terminal and a second terminal portion connected to the bus bar, and the contact portion includes the second terminal portion. The contact surface of the contact portion may be configured to protrude to the bus bar side from the surface of the second terminal portion excluding the contact portion on the bus bar side.
If comprised in this way, when providing the contact part which protrudes toward the bus-bar, since it is not necessary to make the board | plate thickness of an external terminal thin, a conduction | electrical_connection resistance is not increased and rigidity can be maintained.

Further, in the secondary battery of the present invention, an annular bus bar side groove is provided on the bus bar side of the external terminal as a peripheral portion surrounding the contact portion, and the inner diameter of the bus bar side groove is smaller than the width of the bus bar. The outer diameter may be larger than the width of the bus bar.
If comprised in this way, the contact part which protruded toward the bus-bar can be provided by simple process rather than providing with the structure mentioned above.

Moreover, in the secondary battery of this invention, it is desirable that the outer periphery of the contact surface of a contact part is located inside the outer periphery of an engaging member.
With this configuration, when the fastening member is tightened, the contact pressure applied to the external terminal by the engagement member via the bus bar by the axial force of the fastening member is the contact surface of the contact portion (contact portion side contact surface). ) Can be received evenly, so that it is possible to prevent the external terminal from forming a recess along the outer periphery of the nut.

  The present invention also provides an external terminal of a secondary battery that is fixed by being pressed against the bus bar as the fastening member is tightened, and includes a through hole through which the shaft portion of the fastening member is inserted, and a peripheral portion of the through hole. And a seating portion that contacts the head of the fastening member, and the seating portion protrudes toward the head from the periphery of the seating portion, and the outer peripheral edge of the contact surface with respect to the head is It is located inside the outer peripheral edge of the head portion that contacts the seating portion, and extends to the external terminal of the secondary battery, which is not in contact with the head portion except at the seating portion.

  According to the present invention, it is possible to satisfactorily fasten the bus bar and the external terminal without causing a single contact even when refastening.

It is a perspective view of the assembled battery formed by connecting a plurality of secondary batteries according to the first embodiment. It is sectional drawing which shows the secondary battery of 1st Embodiment. It is a disassembled perspective view of the cover member with which the secondary battery is provided. It is sectional drawing which shows the fastening of the external terminal and bus bar in the secondary battery. It is a bottom view of the external terminal which shows the positional relationship of the external terminal with which the secondary battery is equipped, and a volt | bolt. It is a top view of the external terminal which shows the positional relationship of the external terminal with which the secondary battery is equipped, a bus bar, and an external terminal and a nut. It is sectional drawing which shows the fastening of the external terminal and bus bar in the secondary battery of 2nd Embodiment. It is a bottom view of the external terminal with which the secondary battery is provided. It is sectional drawing which shows the fastening of the external terminal and bus bar in the secondary battery of 3rd Embodiment. It is a bottom view of the external terminal which shows the positional relationship of the external terminal with which the secondary battery is equipped, and a volt | bolt. It is a top view of the external terminal which shows the positional relationship of the external terminal with which the secondary battery is equipped, a bus bar, and an external terminal and a nut. It is sectional drawing which shows the fastening of the external terminal and bus bar in the conventional secondary battery.

(First embodiment)
Hereinafter, embodiments of the secondary battery of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an assembled battery 1 configured by connecting a plurality of secondary batteries 100 (hereinafter also simply referred to as “battery 100”) of the present embodiment. FIG. 2 is a cross-sectional view showing the secondary battery 100 of this embodiment. The assembled battery 1 shown in FIG. 1 is mounted on a vehicle such as a hybrid car or an electric vehicle as part or all of a power source. Moreover, this assembled battery 1 can also be mounted on battery-operated equipment other than vehicles. In this specification, unless otherwise specified, the top, bottom, left, and right refer to FIG. 2, and the front side of the page in FIG. 2 is the front and the back side of the page is the back.

  As shown in FIG. 1, the assembled battery 1 includes 50 batteries 100, 100, bus bars 2, 2 that connect the batteries 100 in series, and plate-like members 3 that are alternately stacked with the batteries 100. And two end plates (first end plate 4 and second end plate 5) disposed on both ends of the stacking direction DL with the battery 100 and the plate-like member 3 interposed therebetween. The assembled battery 1 includes a nut (engagement) that fastens the bus bar 2 and the positive external terminal 137 (described later) or the negative external terminal 147 (described later) together with the positive bolt 139 (described later) or the negative bolt 149 (described later) of the battery 100. 9). In the assembled battery 1, a plurality of batteries 100, 100 arranged in a line in the stacking direction DL are accommodated in the assembled battery case 6.

  Among them, the first end plate 4 and the second end plate 5 which are made of metal and have a rectangular plate shape are arranged on both ends in the stacking direction DL of the plurality of batteries 100, 100, and press each battery 100, 100, These dimensional changes in the stacking direction DL are suppressed. In addition, the plate-like member 3 made of an insulating resin includes a plurality of rectangular strip-shaped recesses 3 </ b> G extending along the longitudinal direction of the battery 100 on the surface in contact with the battery 100. A plurality of rectangular gaps through which air can flow are formed between the battery 100 and the plate-like member 3 by the recesses 3G, and cooling the battery 100 by supplying cooling air to the gaps. Is possible.

  Further, the flat bus bar 2 made of pure copper (C1100) has through holes 2H (see FIG. 4) on both ends thereof. These through holes 2H are for inserting a positive electrode bolt 139 (described later) or a negative electrode bolt 149 (described later) of the batteries 100 when the batteries 100 are connected to each other. The assembled battery 1 of this embodiment is a form in which a plurality of batteries 100, 100 are connected in series. One bus bar 2 has one through hole 2H having a positive electrode bolt 139 and the other through hole 2H having a negative electrode. Bolts 149 are respectively inserted (see FIG. 1).

  As shown in FIG. 2, the battery 100 constituting the assembled battery 1 is a lithium ion secondary battery including an electrode body 150 and a battery case 110 that accommodates the electrode body 150. The battery 100 is connected to the positive electrode plate 151 of the electrode body 150 in the battery case 110, and has a positive electrode extending member (positive electrode side electrode body connection terminal) 130 that penetrates the battery case 110 and extends to the outside. A positive external terminal 137 disposed outside the battery case 110. The positive electrode extension member 130 and the positive electrode external terminal 137 constitute a positive electrode terminal member (corresponding to an electrode terminal member) 30.

  In addition, the battery 100 is connected to the negative electrode plate 156 of the electrode body 150 in the battery case 110, and a negative electrode extending member (electrode body connection terminal on the negative electrode side) 140 that extends through the battery case 110 to the outside, A negative electrode external terminal 147 disposed outside the battery case 110. The negative electrode extension member 140 and the negative electrode external terminal 147 constitute a negative electrode terminal member (corresponding to an electrode terminal member) 40.

  The battery 100 further includes a positive bolt (corresponding to a fastening member, also referred to as a positive fastening member) 139 that is located outside the battery case 110 and is electrically connected (can be connected) to the positive external terminal 137, a negative electrode And a negative electrode bolt (corresponding to a fastening member, also referred to as a negative electrode fastening member) 149 that is electrically connected (can be connected) to the external terminal 147. The battery 100 further includes a first insulating member 170 interposed between the positive electrode extending member 130 or the negative electrode extending member 140 and the battery case 110, and a second insulating member 180 disposed on the battery case 110.

  The battery case 110 includes a rectangular box-shaped case main body 111 having an opening 111d and a plate-shaped lid member 113 that closes the opening 111d of the case main body 111. The case body 111 and the lid member 113 are integrated by welding.

  The lid member 113 has a rectangular plate shape, and circular through holes 113h and 113k penetrating the lid member 113 are formed at both ends in the longitudinal direction (left and right direction in FIG. 2). In addition, a safety valve 113j is provided at the center of the lid member 113 in the longitudinal direction. The safety valve 113j is formed integrally with the lid member 113 and forms a part of the lid member 113.

  A liquid injection port 113n for injecting an electrolyte (not shown) into the battery case 110 is formed between the safety valve 113j and the through hole 113k of the lid member 113. The liquid inlet 113n is sealed with a liquid stopper 113m.

  The electrode body 150 is a flat wound electrode body that is wound in a flat shape via a separator 159 between a strip-like positive electrode plate 151 and a negative electrode plate 156. Among these, the positive electrode plate 151 has a strip-like positive electrode foil 152 made of pure aluminum, and a positive electrode active material layer (not shown) disposed on a part of the surface of the positive electrode foil 152. On the other hand, the negative electrode plate 156 includes a strip-shaped negative electrode foil 157 made of pure copper and a negative electrode active material layer (not shown) disposed on a part of the surface of the negative electrode foil 157.

  The first insulating member 170 made of an insulating resin electrically insulates the positive electrode extending member 130 and the battery case 110 (lid member 113) or the negative electrode extending member 140 and the battery case 110 (lid member 113). To do. The first insulating member 170 includes an upper surface 131f (described later) of the pedestal portion 131 of the positive electrode extending member 130, or an upper surface 141f (described later) of the pedestal portion 141 of the negative electrode extending member 140, and a battery case 110 (lid And the member 113) are elastically compressed in the thickness direction of the member (up and down direction in FIG. 2). Therefore, the through holes 113h and 113k of the lid member 113 are sealed.

  The second insulating member 180 made of an insulating resin electrically insulates the positive electrode external terminal 137 and the positive electrode bolt 139 or the negative electrode external terminal 147 and the negative electrode bolt 149 from the battery case 110 (lid member 113).

  The positive electrode bolt 139 is a metal hexagon bolt, and has a hexagonal head 139b and a cylindrical shaft portion 139c in plan view as shown in FIG. The shaft portion 139c is a screw shaft 139d whose surface is screwed. The head 139b is held non-rotatably by the second insulating member 180 in a state where the shaft portion 139c of the positive electrode bolt 139 is inserted into a through hole 137c of the positive electrode external terminal 137 described later (see FIGS. 2 and 3). ). In the assembled battery 1 according to the present embodiment, the positive external terminal 137 and the bus bar 2 are inserted into the screw shaft 139d of the positive bolt 139, and the nut 9 described above is further screwed together. The bus bar 2 is fastened.

  Similarly to the positive electrode bolt 139, the negative electrode bolt 149 is also a metal hexagon bolt, and has a hexagonal head portion 149b and a cylindrical shaft portion 149c in plan view. In FIG. 3, the positive-side member is shown without parentheses, and the negative-side member is shown with parentheses. The shaft portion 149c is a screw shaft 149d having a surface threaded. The head 149b is non-rotatably held by the second insulating member 180 in a state where the shaft portion 149c of the negative electrode bolt 149 is inserted into a through hole 147c of the negative electrode external terminal 147 described later (see FIGS. 2 and 3). ). In the assembled battery 1 according to the present embodiment, the negative electrode external terminal 147 and the bus bar 2 are inserted into the screw shaft 149d of the negative electrode bolt 149, and the nut 9 described above is further screwed. The bus bar 2 is fastened.

  As shown in FIGS. 2 and 3, the positive electrode extension member 130 is made of pure aluminum (A1050-H24 material), and includes a pedestal portion 131, a shaft portion 132, a positive electrode connection portion 134, and a positive electrode caulking portion 133. ing. Of these, the pedestal 131 has a rectangular plate shape and is positioned inside the battery case 110. The shaft portion 132 has a cylindrical shape protruding from the upper surface 131 f of the pedestal portion 131 and is inserted into the through hole 113 h of the lid member 113 forming the battery case 110. The positive caulking portion 133 is a portion connected to the upper end of the shaft portion 132 and is caulked (deformed so as to expand in diameter) to have a disk shape, and is electrically and mechanically connected to a positive electrode external terminal 137 described later. Connected to. The positive electrode connection portion 134 is welded to the positive electrode plate 151 (positive electrode foil 152) of the electrode body 150 in a form extending from the lower surface 131b of the pedestal portion 131 to the bottom surface 110b side of the battery case 110.

  In addition, the positive electrode caulking part 133 before caulking deformation has a cylindrical shape (see FIG. 3). When the battery is manufactured, the first insulating member 170, the lid member 113, the second insulating member 180, and the positive electrode external terminal 137 are inserted in this order together with the shaft portion 132 (see FIG. 3), and the tip portion (positive electrode crimping portion) 133) is protruded to the outside of the battery case 110 from the positive external terminal 137. Then, the positive electrode crimping portion 133 is expanded in diameter so as to be expanded and plastically deformed, and the positive electrode external terminal 137 is crimped and fixed to the lid member 113 via the second insulating member 180 (see FIG. 2).

  On the other hand, the negative electrode extension member 140 is made of pure copper (C1100-1 / 2H material), and has a pedestal portion 141, a shaft portion 142, a negative electrode connection portion 144, and a negative electrode caulking portion 143, similar to the positive electrode extension member 130. doing. Of these, the pedestal portion 141 has a rectangular plate shape and is located inside the battery case 110. The shaft portion 142 has a cylindrical shape protruding from the upper surface 141 f of the pedestal portion 141 and is inserted through the through hole 113 k of the lid member 113. The negative electrode caulking portion 143 is a portion connected to the upper end of the shaft portion 142, and is caulked (deformed so as to expand in diameter) to form a disk shape, and is electrically and mechanically connected to a negative electrode external terminal 147 described later. Connected to. The negative electrode connecting portion 144 is welded to the negative electrode plate 156 (negative electrode foil 157) of the electrode body 150 in a form extending from the lower surface 141b of the pedestal portion 141 toward the bottom surface 110b of the battery case 110.

  In addition, the negative electrode crimping part 143 before caulking deformation also has a cylindrical shape like the positive electrode side (see FIG. 3). When the battery is manufactured, the first insulating member 170, the cover member 113, the second insulating member 180, and the negative electrode external terminal 147 are inserted in this order together with the shaft portion 142 (see FIG. 3), and the tip portion (negative electrode crimping portion) 143) is protruded to the outside of the battery case 110 from the negative external terminal 147. Then, the negative electrode crimping portion 143 is expanded in diameter so as to be expanded and plastically deformed, and the negative electrode external terminal 147 is crimped and fixed to the lid member 113 via the second insulating member 180 (see FIG. 2).

  The positive electrode external terminal 137 is formed by forming a plate material made of an Al—Mg aluminum alloy (A5052-H38 material) into a substantially Z shape (crank shape) in a side view. The positive external terminal 137 includes a fixed portion (corresponding to the first terminal portion) 137f fixed by the positive electrode crimping portion 133, a connecting portion (corresponding to the second terminal portion) 137g connected to the positive electrode bolt 139, and a fixed portion. It has the connection part 137h which connects 137f and the connection part 137g. A through hole 137c is formed through the connecting portion 137g, and the shaft portion 139c of the positive electrode bolt 139 described above is inserted into the through hole 137c. Further, the fixing portion 137f is also formed with a through hole 137b penetrating therethrough, and the shaft portion 132 of the positive electrode extending member 130 is inserted into the through hole 137b.

  On the other hand, the negative electrode external terminal 147 is formed by forming a plate made of the same pure copper (C1100-1 / 2H material) as the negative electrode extending member 140 into a substantially Z shape (crank shape) in a side view. The negative external terminal 147 includes a fixed portion (corresponding to the first terminal portion) 147f fixed by the negative electrode crimping portion 143, a connecting portion (corresponding to the second terminal portion) 147g connected to the negative electrode bolt 149, and a fixed portion. It has the connection part 147h which connects 147f and the connection part 147g. The connecting portion 147g is formed with a through hole 147c passing through the connecting portion 147g, and the shaft portion 149c of the negative electrode bolt 149 is inserted into the through hole 147c. Further, the fixing portion 147f is also formed with a through hole 147b penetrating therethrough, and the shaft portion 142 of the negative electrode extending member 140 is inserted into the through hole 147b.

  Next, a characteristic configuration of the present invention will be described with reference to FIGS. Since the positive electrode side and the negative electrode side have the same configuration (because the positive electrode external terminal 137 and the negative electrode external terminal 147 have the same configuration), only the positive electrode side (positive electrode external terminal 137) will be described below. Description of the negative electrode external terminal 147) is omitted.

  As shown in FIGS. 4 and 5, the positive external terminal 137 is a lower convex portion (corresponding to a seating portion) protruding downward on the lower surface side of the peripheral portion 137 e of the through hole 137 c provided in the connection portion 137 g. 50. That is, the lower convex portion 50 protrudes toward the head 139b of the positive electrode bolt 139. In other words, the lower convex portion 50 protrudes in the direction of increasing the plate thickness along the plate thickness direction of the positive electrode external terminal 137.

  The lower convex portion 50 has an annular shape surrounding the through hole 137c, and is formed by pressing, forging, or the like. The lower surface 50a of the lower convex part 50 is a plane along a horizontal plane, and the lower surface (surface on the head 139b side) 70a of the general part 70 excluding the lower convex part 50 and the upper convex part 60 described later in the connection part 137g. Is located below. The lower surface 50a of the lower convex portion 50 is a contact surface (sitting portion side contact surface) that comes into contact with the surface 139ba (upper surface, head side contact surface in FIG. 4) of the head 139b of the positive bolt 139. The outer diameter D1 (see FIG. 4) of the lower surface (the seating portion side contact surface) 50a of the lower convex portion 50 is smaller than the outer diameter φ1 (see FIG. 4) of the head 139b of the positive bolt 139. That is, the outer peripheral edge 50b of the lower surface 50a of the lower convex part 50 is located inside the outer peripheral edge 139bb of the head 139b of the positive electrode bolt 139 (see FIG. 5). In other words, the area of the lower surface 50a of the lower convex portion 50 is smaller than the area of the upper surface 139ba of the head 139b of the positive electrode bolt 139. The outer peripheral edge portion 50c of the lower convex portion 50 has a tapered shape inclined downward from the outside toward the inside as seen in the radial direction of the through hole 137c (see FIG. 4). In the present specification, unless otherwise specified, the inside and the outside are when the direction of expanding the diameter from the center as viewed in the radial direction of the through hole 137c of the positive electrode external terminal 137 is outward and the opposite is inward. Means inside and outside.

  Thus, in this embodiment, when the positive electrode external terminal 137 and the bus bar 2 are inserted into the shaft portion 139c of the positive electrode bolt 139 and the nut 9 is attached and the positive electrode bolt 139 is tightened, the head 139b Only the contact surface 50 a of the convex portion 50 is in contact with the positive external terminal 137. The axial force due to this tightening is uniformly applied to the contact surface 50 a of the lower convex portion 50. Therefore, even when tightened with high torque (for example, about 10 N), the lower convex portion 50 is deformed by being slightly compressed along the plate thickness direction (however, the compression width is uniform along the plate thickness direction). However, the head 139b does not decrease into the positive external terminal 137. That is, parts other than the lower convex part 50 are not deformed. Therefore, even if it is necessary to re-fasten the bus bar 2 at the time of replacement of one battery 100 constituting the assembled battery 1, the one-side contact as shown in FIG. 12 does not occur. Therefore, the bus bar 2 and the positive electrode external terminal 137 can be connected well.

  4 and 6, the positive electrode external terminal 137 has an upper convex portion (corresponding to a contact portion) 60 protruding upward on the upper surface side of the peripheral edge portion 137e of the through hole 137c. . That is, the upper protrusion 60 protrudes toward the bus bar 2. In other words, the upper convex portion 60 protrudes in the direction of increasing the plate thickness along the plate thickness direction of the positive electrode external terminal 137.

  The upper convex portion 60 has a shape obtained by vertically inverting the lower convex portion 50. That is, the upper convex portion 60 has an annular shape surrounding the through hole 137c. The upper convex portion 60 is formed by pressing or forging. The upper surface 60a of the upper convex portion 60 is a plane along the horizontal plane, and is higher than the upper surface (surface on the bus bar 2 side) 70b of the general portion 70 excluding the upper convex portion 60 and the lower convex portion 50 in the connecting portion 137g. Is located. The upper surface 60a of the upper convex portion 60 is a contact surface (contact portion side contact surface) that comes into contact with the surface 2a of the bus bar 2 (the lower surface in FIG. 4, the bus bar side contact surface). The outer diameter D2 (see FIG. 4) of the upper surface (contact portion side contact surface) 60a of the upper convex portion 60 is smaller than the width dimension W (see FIG. 4) of the bus bar 2. That is, the outer peripheral edge 60b of the upper surface 60a of the upper convex part 60 is located inside the outer edge 2b of the bus bar 2 (see FIG. 6).

  Further, the outer diameter D2 (see FIG. 4) of the upper surface (contact portion side contact surface) 60a of the upper convex portion 60 is smaller than the outer diameter φ2 of the nut 9 (see FIG. 4). That is, the outer peripheral edge 60b of the upper surface 60a of the upper convex part 60 is located inside the outer peripheral edge 9a of the nut 9 (see FIG. 6).

  In the present embodiment, the outer diameter D2 (see FIG. 4) of the upper surface (contact portion side contact surface) 60a of the upper convex portion 60 is the outer diameter D1 of the lower surface (seat portion side contact surface) 50a of the lower convex portion 50 (see FIG. 4). (See FIG. 4). Further, the outer peripheral edge portion 60c of the upper convex portion 60 has a tapered shape inclined upward from the outside toward the inside as seen in the radial direction of the through hole 137c (see FIG. 4).

  Thus, in this embodiment, when the positive electrode external terminal 137 and the bus bar 2 are inserted into the shaft portion 139c of the positive electrode bolt 139 and the nut 9 is attached and the positive electrode bolt 139 is tightened, the bus bar 2 Only the contact surface 60 (contact portion side contact surface) 60a contacts the positive external terminal 137. The pressing force of the bus bar 2 against the positive external terminal 137 by the axial force during tightening is uniformly applied to the contact surface (contact portion side contact surface) 60a of the upper convex portion 60. Therefore, even when tightened with a high torque (for example, about 10 N), the upper convex portion 60 is deformed by being somewhat compressed along the plate thickness direction (however, the compression width is uniform along the plate thickness direction). Even if it exists, the bus bar 2 does not decrease into the positive electrode external terminal 137. That is, parts other than the upper convex part 60 are not deformed. Therefore, even when it is necessary to re-fasten the bus bar 2 such as when replacing one battery 100 constituting the assembled battery 1, the fastening due to the bus bar 2 being shifted to a position different from that at the first fastening time. It is possible to prevent a defect (fastening failure due to insufficient surface contact with a sufficient area).

  Further, since the outer diameter D2 (see FIG. 4) of the upper surface (contact portion side contact surface) 60a of the upper convex portion 60 is smaller than the outer diameter φ2 (see FIG. 4) of the nut 9, the nut force is determined by the axial force at the time of fastening. The force with which 9 presses the positive electrode external terminal 137 via the bus bar 2 is also uniformly applied to the contact surface (contact portion side contact surface) 60 a of the upper convex portion 60. Therefore, it is possible to prevent a fastening failure at the time of re-fastening for the same reason as described above.

  As described above, the secondary battery 100 of the present embodiment includes the positive electrode external terminal 137 and the shaft inserted into the through hole 137c formed in the positive electrode external terminal 137 and the through hole 2H formed in the bus bar 2. The bus bar 2 and the positive external terminal 137 are sandwiched between a nut 9 (engagement member) attached to the shaft portion 139c and the head portion 139b, which includes a portion 139c and a head portion 139b having a larger diameter than the shaft portion 139c. By being fastened, a positive bolt 139 (fastening member) for fastening the bus bar 2 and the positive external terminal 137 is provided. The positive external terminal 137 includes a lower convex portion 50 (sitting portion) that comes into contact with the head portion 139b on the side of the head portion 137b in the peripheral edge portion 137e of the through hole 137c, and the lower convex portion 50 is provided with the lower convex portion. It protrudes toward the head 139b rather than the surrounding part (general part 70) surrounding the part 50. In other words, the head 139b side of the peripheral portion 137e of the through hole 137c of the positive electrode external terminal 137 protrudes toward the head 139b from the peripheral portion (general portion 70), and the head 139b contacts at the time of fastening. It becomes the lower side convex part 50 to do. The outer peripheral edge 50b of the contact surface 50a with the head 139b in the lower convex part 50 is located inside the outer peripheral edge 139bb of the head 139b, and the head 139b is lower than the positive external terminal 137. It contacts only with the contact surface 50a of the side convex part 50. FIG. In other words, the outer peripheral edge 50b of the contact surface (seat portion side contact surface) 50a with the head 139b in the lower convex portion 50 is the contact surface (head side contact surface) with the lower convex portion 50 in the head 139b. The outer peripheral edge 139bb of the head 139b (the outer peripheral edge 139bb of the head-side contact surface 139ba) is not in contact with any part of the positive electrode external terminal 137.

  Therefore, when the positive bolt 139 (fastening member) is tightened, the surface pressure applied to the positive external terminal 137 by the head 139b by the axial force of the positive bolt 139 is the contact surface of the lower convex portion 50 (sitting portion). It will be received uniformly only by 50a. Therefore, even if the contact surface 50a of the positive external terminal 137 is pushed by the head 139b and the lower convex portion 50 is uniformly compressed, the head 139b is reduced with respect to the positive external terminal 137. There is no. That is, the positive electrode external terminal 137 is not formed with a recess along the outer peripheral edge 139bb of the head 139b. Therefore, it is possible to prevent the occurrence of a problem that the head 139b comes into contact with the positive external terminal 137 when the positive bolt 139 is shifted to a different fastening position from that at the first fastening. That is, even during re-fastening, the head 139b of the positive bolt 139 and the positive external terminal 137 can be brought into contact with each other with a sufficient area, so that good fastening can be performed. Therefore, even when the fastening is performed on the premise that the bus bar 2 and the positive electrode external terminal 137 are re-fastened, the tightening is performed with high torque without worrying about plastic deformation (depression formation) of the positive electrode external terminal 137. be able to.

  Further, in the secondary battery 100 of the present embodiment, the positive external terminal 137 includes an upper convex portion 60 (contact portion) that comes into contact with the bus bar 2 on the side where the bus bar 2 is arranged at the peripheral edge portion 137e of the through hole 137c. The convex part 60 protrudes toward the bus bar 2 from the peripheral part (general part 70) surrounding the upper convex part 60. In other words, the bus bar 2 side of the peripheral edge portion 137e of the through hole 137c of the positive electrode external terminal 137 protrudes toward the bus bar 2 from the peripheral portion (general portion 70), and the upper protrusion that the bus bar 2 contacts at the time of fastening. Part 60. The outer peripheral edge 60b of the contact surface 60a of the upper convex portion 60 with the bus bar 2 is located inside the outer edge 2b of the bus bar 2, and the bus bar 2 contacts the positive external terminal 137 with the upper convex portion 60. It is in contact only with the surface 60a. In other words, the outer peripheral edge 60b of the contact surface (contact portion side contact surface) 60a with the bus bar 2 in the upper convex portion 60 is the outer edge 2b of the contact surface (bus bar side contact surface) 2a with the upper convex portion 60 in the bus bar 2. The outer edge 2b of the bus bar 2 (the outer edge 2b of the bus bar side contact surface 2a) is not in contact with any part of the positive external terminal 137.

  Therefore, when the positive electrode bolt 139 (fastening member) is tightened, the surface pressure that the bus bar 2 applies to the positive electrode external terminal 137 by the axial force of the positive electrode bolt 139 is the contact surface of the upper convex portion 60 (the contact portion side contact surface). ) Only 60a can be received uniformly. Therefore, even if the contact surface (contact portion side contact surface) 60a of the positive external terminal 137 is pushed by the bus bar 2 and the upper convex portion 60 is uniformly compressed, the bus bar 2 with respect to the positive external terminal 137 may be compressed. Will not decrease. That is, the positive electrode external terminal 137 is not formed with a recess along the outer edge 2b of the bus bar 2. Therefore, it is possible to prevent the occurrence of a problem that the bus bar 2 rides on the positive electrode external terminal 137 when the bus bar 2 is shifted to a position different from that at the time of the initial fastening at the time of re-fastening. That is, even at the time of re-fastening, the bus bar 2 and the positive external terminal 137 can be brought into contact with each other with a sufficient area, so that good fastening can be performed. Therefore, even when the fastening is performed on the premise that the bus bar 2 and the positive electrode external terminal 137 are re-fastened, the tightening is performed with high torque without worrying about the plastic deformation of the positive electrode external terminal 137 due to the pushing of the bus bar 2. be able to.

  Moreover, in the secondary battery 100 of this embodiment, the outer peripheral edge 60b of the contact surface 60a of the upper convex part 60 (contact part) is located inside the outer peripheral edge 9a of the nut 9 (engagement member). Therefore, when the positive bolt 139 (fastening member) is tightened, the surface pressure that the nut 9 applies to the positive external terminal 137 via the bus bar 2 by the axial force of the positive bolt 139 is the contact surface 60a of the upper convex portion 60. Therefore, it is possible to prevent the positive electrode external terminal 137 from forming a recess along the outer peripheral edge 9 a of the nut 9.

(Second Embodiment)
In the second embodiment, as shown in FIGS. 7 and 8, the peripheral edge portion 137 e of the through hole 137 c of the positive electrode external terminal 137 is inside the lower convex portion 50 (inside when viewed in the radial direction of the through hole 137 c). ), A lower annular recess (corresponding to a head-side recess) 56 surrounding the through-hole 137c is formed. Further, in the peripheral edge portion 137e of the through hole 137c of the positive electrode external terminal 137, on the inner side of the upper convex portion 60 (inside when viewed in the radial direction of the through hole 137c), an upper annular concave portion (busbar side) surrounding the through hole 137c. 66 (corresponding to a concave portion) is formed. Since the other points are the same as those of the first embodiment, the same reference numerals are given and the description thereof is omitted.

  The bottom surface 56 a of the lower annular recess 56 is located above the contact surface 50 a of the lower projection 50. In other words, the bottom surface 56 a of the lower annular recess 56 is recessed along the thickness direction with respect to the contact surface 50 a of the lower protrusion 50. The bottom surface 56 a is at the same height as the lower surface 70 a of the general portion 70 outside the lower convex portion 50. A side surface 56b of the lower annular recess 56 connects the contact surface 50a and the bottom surface 56a. The side surface 56b is a tapered surface inclined upward from the outside to the inside.

  The outer diameter of the lower annular recess 56, that is, the inner diameter d1 (see FIG. 7) of the lower projection 50 is larger than the diameter D3 (see FIG. 7) of the shaft portion 139c of the positive bolt 139. Accordingly, even when there is an upward protruding portion at the base portion of the shaft portion 139c of the head portion 139b of the positive electrode bolt 139, the protruding portion is prevented from biting into the positive external terminal 137 (reduction). be able to. The protruding portion is formed on the positive electrode bolt 139 when the manufacturing accuracy of the positive electrode bolt 139 is poor, such as cutting, forging, and rolling. The lower annular recess 56 takes into account this.

  On the other hand, the upper annular recess 66 has a shape obtained by vertically inverting the lower annular recess 56. The bottom surface 66 a of the upper annular recess 66 is located below the contact surface 60 a of the upper projection 60. In other words, the bottom surface 66 a of the upper annular recess 66 is recessed along the plate thickness direction with respect to the contact surface 60 a of the upper protrusion 60. The bottom surface 66 a is at the same height as the top surface 70 b of the general portion 70 outside the upper convex portion 60. A side surface 66b of the upper annular recess 66 connects the contact surface 60a and the bottom surface 66a. The side surface 66b is a tapered surface inclined downward from the outside to the inside.

  The outer diameter of the upper annular recess 66, that is, the inner diameter d2 (see FIG. 7) of the upper convex portion 60 is the same as the inner diameter d1 (see FIG. 7) of the lower convex portion 50, and the shaft portion 139c of the positive bolt 139 It is larger than the diameter D3 (see FIG. 7). Thereby, even when there is a cylindrical portion protruding downward at the periphery of the through hole 2H of the bus bar 2 (when the periphery of the through hole 2H of the bus bar 2 is standing downward), the cylindrical portion Can be prevented from biting (decreasing) into the positive electrode external terminal 137. The cylindrical portion is formed on the bus bar 2 when, for example, the through hole 2H is burring processed for the purpose of securing the strength of the bus bar 2. The upper annular recess 66 is designed to take account of this.

  In the second embodiment, as shown in FIG. 7, the diameter d4 of the through hole 2H of the bus bar 2 is smaller than the diameter d3 of the through hole 137c of the positive external terminal 137. This is to prevent the bus bar 2 from being greatly deviated from the contact surface 60a of the upper projection 60 during re-fastening.

(Third embodiment)
In the third embodiment, as shown in FIGS. 9 and 10, a seating portion 85 is provided on the lower surface side of the peripheral edge portion 137 e of the through hole 137 c of the positive electrode external terminal 137, and the seating portion 85 is provided on the outer periphery of the seating portion 85. A lower annular groove portion (corresponding to the head-side groove portion) 80 is formed. In other words, by forming the lower annular groove portion 80 on the lower surface side of the positive electrode connecting portion 137g, the seat portion 85 is formed inside the lower annular groove portion 80. As shown in FIGS. 9 and 11, the contact portion 95 is provided on the upper surface side of the peripheral edge portion 137 e of the through hole 137 c of the positive electrode external terminal 137, and the upper annular shape surrounding the contact portion 95 around the outer periphery of the contact portion 95. A groove 90 is formed. By forming the upper annular groove portion 90 on the upper surface side of the positive electrode connecting portion 137g, the contact portion 95 is formed inside the upper annular groove portion 90. Since the other points are the same as those of the first embodiment, the same reference numerals are given and the description thereof is omitted.

  As shown in FIGS. 9 and 10, the surface 85 a (the lower surface in FIG. 9) of the seating portion 85 is at the same height as the lower surface 70 a of the general portion 70 outside the lower annular groove portion 80. The front surface (lower surface) 85a is a contact surface (a seating portion side contact surface) that comes into contact with the head 139b of the positive electrode bolt 139.

  The bottom surface 80 a of the lower annular groove portion 80 is located above the contact surface 85 a of the seating portion 85. The inner surface 80b of the lower annular groove 80 connects the contact surface 85a and the bottom surface 80a, and the outer surface 80c of the lower annular groove 80 connects the lower surface 70a and the bottom surface 80a of the general portion 70.

  As shown in FIG. 9, the inner diameter d <b> 5 of the lower annular groove 80 is smaller than the outer diameter φ <b> 1 of the head 139 b of the positive electrode bolt 139. Further, the outer diameter D4 of the lower annular groove 80 is larger than the outer diameter φ1 of the head 139b of the positive bolt 139. In other words, as shown in FIG. 10, the outer peripheral edge 139bb of the head 139b of the positive bolt 139 is located outside the inner peripheral edge 80d of the lower annular groove 80 and inside the outer peripheral edge 80e of the lower annular groove 80. Is located.

  For this reason, when the positive electrode bolt 139 is tightened, the head 139b comes into contact with the positive electrode external terminal 137 only at the contact surface (seat portion side contact surface) 85a of the seat portion 85. The axial force due to this tightening is uniformly applied to the contact surface 85a of the seating portion 85. Therefore, even when tightened with a high torque (for example, about 10 N), the seating portion 85 is slightly compressed and deformed along the plate thickness direction (however, the compression width is uniform along the plate thickness direction). However, the head 139b does not decrease into the positive external terminal 137. That is, parts other than the seating part 85 are not deformed. Therefore, even if it is necessary to re-fasten the bus bar 2 at the time of replacement of one battery 100 constituting the assembled battery 1, the one-side contact as shown in FIG. 12 does not occur. Therefore, the bus bar 2 and the positive electrode external terminal 137 can be connected well.

  On the other hand, as shown in FIGS. 9 and 11, the surface 95 a (upper surface in FIG. 9) of the contact portion 95 is flush with the upper surface 70 b of the general portion 70 outside the upper annular groove portion (corresponding to the bus bar side groove portion) 90. It is in. This surface (upper surface) 95 a is a contact surface (contact portion side contact surface) that comes into contact with the bus bar 2.

  The bottom surface 90 a of the upper annular groove portion 90 is located below the contact surface 95 a of the contact portion 95. An inner side surface 90b of the upper annular groove portion 90 connects the contact surface 95a and the bottom surface 90a, and an outer surface 90c of the upper annular groove portion 90 connects the upper surface 70b and the bottom surface 90a of the general portion 70.

  As shown in FIG. 9, the inner diameter d6 of the upper annular groove portion 90 is the same as the inner diameter d5 of the lower annular groove portion 80, and is smaller than the width dimension W of the bus bar 2 and the outer diameter φ2 of the nut 9. Further, the outer diameter D5 of the upper annular groove portion 90 is the same as the outer diameter D4 of the lower annular groove portion 80, and is larger than the width dimension W of the bus bar 2 and the outer diameter φ2 of the nut 9. Therefore, as shown in FIG. 11, the outer peripheral edge 9 a of the nut 9 is located outside the inner peripheral edge 90 d of the upper annular groove portion 90 and inside the outer peripheral edge 90 e of the upper annular groove portion 90.

  For this reason, when the positive electrode bolt 139 is tightened, the bus bar 2 comes into contact with the positive electrode external terminal 137 only at the contact surface (contact surface side contact surface) 95a of the contact portion 95. The pressing force of the bus bar 2 against the positive external terminal 137 by the axial force at the time of tightening is uniformly applied to the contact surface (contact portion side contact surface) 95a of the contact portion 95. Therefore, even when tightened with a high torque (for example, about 10 N), the contact portion 95 is deformed by being somewhat compressed along the plate thickness direction (however, the compression width is uniform along the plate thickness direction). However, the bus bar 2 does not decrease into the positive electrode external terminal 137. That is, parts other than the contact part 95 are not deformed. Therefore, even when it is necessary to re-fasten the bus bar 2 such as when replacing one battery 100 constituting the assembled battery 1, the fastening due to the bus bar 2 being shifted to a position different from that at the first fastening time. It is possible to prevent a defect (fastening failure due to insufficient surface contact with a sufficient area).

  Further, the force by which the nut 9 presses the positive electrode external terminal 137 through the bus bar 2 by the axial force at the time of fastening is also uniformly applied to the contact surface (contact portion side contact surface) 95a. Therefore, it is possible to prevent a fastening failure at the time of re-fastening for the same reason as described above.

  In the third embodiment, the lower annular recess 56 (see FIG. 7) and the upper annular recess 66 (see FIG. 7) of the second embodiment may be provided. In such a configuration, in addition to the effects of the third embodiment, the effects of the second embodiment can be achieved.

  In the third embodiment, by providing the lower annular groove 80 (head side groove) and the upper annular groove 90 (bus bar side groove), the seat 85 that protrudes from the periphery toward the head 139b, A contact portion 95 protruding toward the bus bar 2 was provided. Therefore, there is an advantage that the processing of the positive external terminal 137 is easier than providing the lower convex portion 50 and the upper convex portion 60 as in the first embodiment. However, as the positive external terminal 137 is cut inward in the thickness direction, the area of the vertical cross section of the positive external terminal 137 that conducts when energized is reduced, the electrical resistance is increased, and the positive external terminal 137 is increased. The strength of will also decrease. Therefore, the first embodiment is a more preferable form than the third embodiment.

(Other changes)
In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. For example, in the above embodiment, Z-shaped (crank-shaped) terminals are shown as the positive external terminal 137 and the negative external terminal 147. However, for example, a flat or L-shaped terminal can be used. Moreover, although the example which used what has the same shape as the positive electrode external terminal 137 and the negative electrode external terminal 147 was shown in the said embodiment, you may use a terminal with a mutually different shape.

  Moreover, in the said embodiment, although comprised without putting a washer in the head 139b side of the positive electrode bolt 139 (fastening member), you may put a washer. When a washer is inserted on the head 139b side, the "head" including the washer is meant. Therefore, the outer diameter of the washer becomes the outer diameter of the head. Of course, a flanged bolt in which the washer and the head are integrated may be used. In this case, the outer diameter of the flange becomes the outer diameter of the head. Further, the shape of the head of the fastening member is not limited to a hexagon, but may be other shapes such as a square or a circle. That is, although the hexagon bolt was used as the fastening member, any fastening member may be used as long as the bus bar 2 is pressed against and fixed to the positive external terminal 137 as the fastening member is tightened. In other words, any fastening member that clamps the positive external terminal 137 and the bus bar 2 with an axial force may be used. For example, the fastening member may be constituted by a female screw and a fixing nut attached to one end of the female screw. In this case, a nut 9 is attached to the other end of the female screw.

  In the above embodiment, the positive bolt 139 is inserted from below the positive external terminal 137 and the nut 9 is tightened from above. However, the positive bolt 139 may be inserted downward. Of course, depending on the shape of the positive electrode external terminal 137, the positive electrode bolt 139 may be inserted along the left-right direction.

  In the above embodiment, the positive bolt 139 is disposed on the positive external terminal 137 side and the nut 9 is disposed on the bus bar 2 side. However, the nut 9 is disposed on the positive external terminal 137 side and the positive bolt 139 is disposed on the bus bar 2 side. It may be arranged. In such a configuration, there is a possibility that the nut 9 may be reduced to the positive electrode external terminal 137. However, such a decrease can be prevented by the presence of the lower convex portion 50 (sitting portion).

  In the above embodiment, the external terminals 137 and 147 having the lower convex portion 50 and the upper convex portion 60 are used on both the negative electrode side and the positive electrode side, but either the positive electrode external terminal 137 or the negative electrode external terminal 147 is used. Only the thing with the lower side convex part 50 and the upper side convex part 60 may be used. In the above embodiment, since the negative electrode side is made of copper and the positive electrode side is made of aluminum which is softer than copper, the positive electrode external terminal 137 is more likely to be depressed (see reference numeral 250 in FIG. 12). For this reason, it is desirable to provide the lower protrusion 50 and the upper protrusion 60 on the positive electrode external terminal 137. Further, it is not always necessary to provide both the lower convex portion 50 and the upper convex portion 60 on the external terminals 137 and 147, and only the lower convex portion 50 may be provided. Whether to provide the upper convex portion 60 may be determined in consideration of the shape, plate thickness, material, and the like of the bus bar 2. When providing both the lower convex part 50 and the upper convex part 60, the area of the contact surface 50a of the lower convex part 50 and the area of the contact surface 60a of the upper convex part 60 may differ. The area of the bottom surface 56a of the lower annular recess 56 and the area of the bottom surface 66a of the upper annular recess 66 shown in the second embodiment, the area of the bottom surface 80a of the lower annular groove 80 shown in the third embodiment, and the upper side thereof. The area of the bottom surface 90a of the annular groove 90 may also be different.

  Moreover, in the said embodiment, as an electrode terminal member (the positive electrode terminal member 30, the negative electrode terminal member 40), the positive electrode external terminal 137 (negative electrode external terminal 147) and the positive electrode extension member 130 (negative electrode extension member 140) are separate bodies. Some are used, but one may be used. In this case, the portion exposed to the outside of the battery case 110 corresponds to an external terminal. That is, the electrode terminal members (the positive electrode terminal member 30 and the negative electrode terminal member 40) may have any configuration as long as the electric power from the electrode body 150 can be output to the outside.

  In the above embodiment, the lithium secondary battery 100 is exemplified as the battery 100. However, the technical idea of the present invention can be applied to other types of secondary batteries such as a nickel metal hydride battery and a nickel cadmium battery. .

  In the first embodiment, the general portion 70 corresponds to the peripheral portion of the seating portion and the peripheral portion of the contact portion. In the third embodiment, the lower annular groove portion 80 corresponds to the peripheral portion of the seating portion, and the upper annular groove portion 90 corresponds to the peripheral portion of the contact portion.

DESCRIPTION OF SYMBOLS 1 ... Battery pack 2 ... Bus bar 2b ... Outer edge 2H of bus bar ... Through-hole 9 ... Nut (engaging member)
9a ... outer peripheral edge 30 of the nut ... positive electrode terminal member (electrode terminal member)
40 ... Negative electrode terminal member (electrode terminal member)
50 ... Lower convex part (sitting part)
50a: Contact surface 50b of the lower convex portion ... Outer peripheral edge 56 ... Lower annular concave portion (head side concave portion)
56a ... Bottom surface 60 of the lower annular recess ... Upper projection (contact part)
60a: Contact surface 60b of the upper convex portion ... Outer peripheral edge 66 ... Upper annular concave portion (bus bar side concave portion)
66a ... bottom 70 of upper annular recess ... general part 70a ... lower surface (surface on the head side)
70b ... Upper surface (surface on the bus bar side)
80: Lower annular groove (head-side groove)
80d ... Inner peripheral edge 80e ... Outer peripheral edge 85 ... Seating portion 85a ... Contact surface 90 of the seating portion ... Upper annular groove (busbar side groove)
90d ... Inner peripheral edge 90e ... Outer peripheral edge 95 ... Contact part 95a ... Contact surface 100 of the contact part ... Secondary battery 110 ... Battery case 130 ... Positive electrode extension member (electrode body connection terminal)
137 ... Positive electrode external terminal 137c ... Through hole 137e ... Peripheral edge 137f of the through hole ... Fixed portion (first terminal portion)
137g ... Connection part (second terminal part)
139: Positive bolt (fastening member)
139b ... head 139bb ... outer periphery 139c of head ... shaft 140 ... negative electrode extension member (electrode body connection terminal)
147 ... Negative electrode external terminal 149 ... Negative electrode bolt (fastening member)
150 ... Electrode body 151 ... Positive electrode plate (positive electrode)
156 ... Negative electrode plate (negative electrode)

Claims (10)

A secondary battery that is connected to another secondary battery by a bus bar to form an assembled battery,
An electrode body;
A battery case containing the electrode body;
An electrode body connection terminal connected to the positive electrode or the negative electrode of the electrode body in the battery case, and an external terminal disposed outside the battery case and electrically connected to the electrode body connection terminal; An electrode terminal member comprising:
A shaft portion inserted through a through hole formed in the external terminal and a through hole formed in the bus bar; and an engagement member attached to the shaft portion, the head portion having a larger diameter than the shaft portion; A fastening member that fastens the bus bar and the external terminal by clamping the bus bar and the external terminal between the head and the head; and
The external terminal is provided with a seating portion in contact with the head on the side of the head at the periphery of the through-hole,
The seating part protrudes toward the head from the surrounding part surrounding the seating part,
The outer peripheral edge of the contact surface with the head in the seating portion is located inside the outer peripheral edge of the head,
The secondary battery according to claim 1, wherein the head is in contact with the external terminal only at the contact surface of the seating portion. The secondary battery according to claim 1,
The external terminal is provided with an annular head-side recess having a bottom surface that is recessed along the plate thickness direction from the contact surface of the seating portion inside the seating portion at the periphery of the through hole. A secondary battery characterized by that. A secondary battery according to claim 1 or claim 2,
The external terminal includes a contact portion in contact with the bus bar on a side where the bus bar is arranged at a peripheral portion of the through hole,
The contact portion protrudes toward the bus bar from the surrounding portion surrounding the contact portion,
The outer peripheral edge of the contact surface with the bus bar in the contact portion is located inside the outer edge of the bus bar,
The secondary battery is characterized in that the external terminal is in contact with the bus bar only at the contact surface of the contact portion. The secondary battery according to claim 3,
The external terminal is provided with an annular bus bar-side recess having a bottom surface that is recessed along the plate thickness direction from the contact surface of the contact portion inside the contact portion at the periphery of the through hole. A secondary battery characterized by. A secondary battery according to any one of claims 1 to 4,
The external terminal includes a first terminal portion connected to the electrode body connection terminal, and a second terminal portion connected to the bus bar,
The seating portion is provided on the second terminal portion,
The contact surface of the said seating part protrudes in the said head side rather than the surface of the said head side except the said seating part in the said 2nd terminal part, The secondary battery characterized by the above-mentioned. A secondary battery according to any one of claims 1 to 4,
On the head side of the external terminal, an annular head-side groove is provided as a peripheral part surrounding the seating part,
The outer peripheral edge of the head is positioned outside the inner peripheral edge of the head-side groove and is positioned inside the outer peripheral edge of the head-side groove. A secondary battery according to claim 3 or claim 4, wherein
The external terminal includes a first terminal portion connected to the electrode body connection terminal, and a second terminal portion connected to the bus bar,
The contact portion is provided on the second terminal portion;
The secondary battery is characterized in that a contact surface of the contact portion protrudes closer to the bus bar side than a surface of the second terminal portion on the bus bar side excluding the contact portion. A secondary battery according to claim 3 or claim 4, wherein
On the bus bar side of the external terminal, an annular bus bar side groove is provided as a peripheral portion surrounding the contact portion,
The secondary battery, wherein the bus bar side groove has an inner diameter smaller than a width dimension of the bus bar and an outer diameter larger than the width dimension of the bus bar. A secondary battery according to claim 3, claim 4, claim 7 or claim 8,
The secondary battery according to claim 1, wherein an outer peripheral edge of the contact surface of the contact portion is positioned inside an outer peripheral edge of the engaging member. An external terminal of a secondary battery that is fixed by being pressed against the bus bar as the fastening member is tightened,
A through hole through which the shaft portion of the fastening member is inserted;
A seating portion provided at a peripheral portion of the through-hole and in contact with a head portion of the fastening member;
The seating part is
Protrudes from the periphery of the seating portion toward the head,
The outer peripheral edge of the contact surface with respect to the head is located inside the outer peripheral edge of the head in contact with the seat;
An external terminal of a secondary battery, wherein the external terminal is not in contact with the head at a place other than the seating portion.

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