JP2014179196A - Connection structure of secondary battery and secondary battery device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery connection structure which allows for easy and reliable connection of the electrode terminal of a battery, and to provide a secondary battery device including the same.SOLUTION: A battery connection structure for connecting an electrode terminal having a joint surface provided with an engaging recess includes a planar connection 42 arranged on the joint surface of the electrode terminal, a planar conductive member 40 having an engaging protrusion protruding from the connection and engaging with the engaging recess 28 of the electrode terminal, and a first insertion opening 52 formed to penetrate the connection near the engaging protrusion and facing the engaging recess, and formed of a conductive material and a holding member 62 engaging with the connection and electrode terminal. The holding member has a press protrusion 62b which is pushed into the engaging recess of the electrode terminal through the first insertion opening of the connection, and pressing the engaging protrusion against the inner surface of the engaging recess, and an engagement end 62c which engages with the side edge of the electrode terminal.

Description

  Embodiments described herein relate generally to a connection structure for connecting electrode terminals of a secondary battery, and a secondary battery device including the connection structure.

  In recent years, secondary batteries have been widely used as power sources for electric vehicles, hybrid electric vehicles, electric bicycles, or electric devices. For example, a lithium ion secondary battery, which is a non-aqueous secondary battery, has attracted attention as a power source for electric vehicles and the like because of its high output and high energy density. In order to further increase the capacity and output, a plurality of secondary batteries are arranged side by side in a case, and an assembled battery or a secondary battery device in which these secondary batteries are connected in series or in parallel is used. It has been.

  In a battery pack, each secondary battery (hereinafter referred to as a battery cell) has a positive electrode terminal and a negative electrode terminal. Among the plurality of battery cells, for example, the electrode terminals of two adjacent battery cells are bus bars. The conductive members are connected to each other. In this case, the bus bar is positioned with respect to the electrode terminal, and is connected and fixed to the electrode terminal by bolt bonding or laser welding.

JP 2009-87721 A

  In assembling the assembled battery, when the bus bar is connected to the battery cell by bolting, the number of work steps increases, and it is necessary to securely connect the electrode terminal without damaging the electrode terminal due to the tightening torque. In the case of welding, large-scale equipment is required, and when welding fails, repair is difficult, which can be a factor of reducing manufacturing yield.

  The present invention has been made in view of the above points, and its object is to provide a battery connection structure capable of easily and reliably connecting electrode terminals of a secondary battery, and a secondary battery device including the same. Is to provide.

  According to the embodiment, the battery connection structure of the secondary battery device is a battery connection structure that is connected to an electrode terminal that is provided in a battery cell and has a joint surface in which an engagement recess is formed. A plate-like connecting portion disposed on the joining surface, an engaging convex portion protruding from the connecting portion and engaging in an engaging recess of the electrode terminal, and penetrating the connecting portion in the vicinity of the engaging convex portion A plate-shaped conductive member formed of a conductive material, and a holding member having a spring force that engages with the connection portion and the electrode terminal. A pressing projection that is pushed into the engagement recess of the electrode terminal through the first insertion opening of the connection portion and presses the engagement projection against the inner surface of the engagement recess; and a side edge of the electrode terminal And a holding member having an engaging end portion engaged with the holding member.

FIG. 1 is a perspective view showing a secondary battery device according to the first embodiment. FIG. 2 is an exploded perspective view showing an electrode terminal portion of a battery cell and a bus bar in the secondary battery device. FIG. 3 is an exploded perspective view showing electrode terminals, bus bars, and leaf spring members of battery cells that constitute the battery connection structure of the secondary battery device. FIG. 4 is a cross-sectional view showing an electrode terminal of the battery cell. FIG. 5 is a perspective view showing the back side of the bus bar. FIG. 6 is a perspective view showing an engaging convex portion of the bus bar. FIG. 7 is a perspective view showing a state in which the bus bar and the leaf spring member are connected to electrode terminals. FIG. 8 is a cross-sectional view of the connecting portion along line AA in FIG. 7. FIG. 9 is an exploded perspective view showing an electrode terminal of the battery cell and a bus bar for fixing welding. FIG. 10 is a perspective view showing an electrode terminal of the battery cell and a bus bar for fixing welding. FIG. 11 is an exploded perspective view showing a battery connection structure of the secondary battery device according to the second embodiment. FIG. 12 is an exploded perspective view showing electrode terminals and bus bars having cross-shaped engaging recesses according to a modification in the secondary battery device according to the second embodiment. FIG. 13 is a perspective view showing the back side of the bus bar. FIG. 14 is an enlarged perspective view showing an engagement convex portion of the bus bar. FIG. 15 is a perspective view showing a state in which a bus bar and a leaf spring member are connected to electrode terminals of battery cells in the second embodiment. 16 is a cross-sectional view of the connecting portion along line BB in FIG.

Hereinafter, a secondary battery device having a battery connection structure according to an embodiment will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a perspective view schematically showing the secondary battery device according to the first embodiment. As shown in FIG. 1, the secondary battery device 10 includes, for example, a rectangular box-shaped case 16 and a plurality of, for example, five battery cells (two) arranged in the case with a predetermined gap therebetween. Secondary battery cell) 12 and a control circuit board (not shown) that monitors and controls the voltage, temperature, etc. of each battery cell, and is configured as an assembled battery (battery module). The electrode terminals of adjacent battery cells 12 are electrically connected by a bus bar 40 as a conductive member.

  As shown in FIG. 1, the case 16 includes a rectangular box-shaped case main body 26 having a bottom wall and an open top surface, and a rectangular plate that is fitted to the upper end edge of the case main body 26 and covers the top opening of the case main body. And a top cover (not shown) that is detachably attached to the upper case. The case body 26 and the upper case 27 are each formed of a synthetic resin having an insulating property, for example, a thermoplastic resin such as a polycarbonate (PC) or polyphenylene ether (PPE).

  2 is an exploded perspective view showing the electrode terminal portion and the bus bar of the battery cell 12, FIG. 3 is a side view showing the electrode terminal, the bus bar, and the leaf spring member of the battery cell constituting the battery connection structure, and FIG. It is sectional drawing of the electrode terminal part of a cell. As shown in FIGS. 1 to 4, each battery cell 12 is configured as a thin non-aqueous secondary battery such as a lithium ion battery, for example. The battery cell 12 includes a flat rectangular box-shaped outer container 18 made of aluminum or the like, and an electrode body 20 housed in the outer container 18 together with a nonaqueous electrolytic solution. The outer container 18 has a container main body 18a having an open upper end and a rectangular plate-shaped lid 18b welded to the container main body 18a to close the opening of the container main body, and the inside is formed airtight. The electrode body 20 is formed in a flat rectangular shape by, for example, winding a positive electrode plate and a negative electrode plate in a spiral shape with a separator interposed therebetween, and further compressing in a radial direction.

  The positive electrode terminal 22 and the negative electrode terminal 23 which are electrode terminals are provided at both ends in the longitudinal direction of the lid body 18b, and are exposed on the lid body 18b. The positive electrode terminal 22 and the negative electrode terminal 23 are electrically connected to the positive electrode and the negative electrode of the electrode body 20, respectively. A pressure release valve 24 that functions as a gas exhaust mechanism is formed at the center of the lid 18b. When gas is generated in the outer casing 18 due to an abnormal mode or the like of the battery cell 12 and the internal pressure in the outer casing rises to a predetermined value or more, the pressure release valve 24 is opened, and the inner pressure is lowered to rupture the outer casing 18. To prevent such problems.

  As shown in FIGS. 2 to 4, the positive electrode terminal 22 and the negative electrode terminal 23 of the battery cell 12 are, for example, bases 22 a and 23 a formed in a rectangular shape, and columnar connection terminals extending from the bottom center of the base. 22b and 23b, and columnar connection terminals 22b protruding outward from the upper surface. The base and the connection terminal are integrally formed of a conductive metal such as aluminum or copper. The bases 22a and 22b are placed on the lid 18b via the insulating sheets 21a and 21b, respectively. The connection terminal 22b extends through the lid 18b into the exterior container 18 and is connected to the electrode body 20. ing.

  The bases 22a and 23a of the electrode terminals are fixed on the lid 18b so that the longitudinal direction thereof coincides with the longitudinal direction of the lid 18b. The upper surfaces of the bases 22a and 23a form flat rectangular joint surfaces 24a and 24b. In the present embodiment, two engagement recesses 28 are formed in the bases 22a and 23a, and these engagement recesses 28 open to the joint surfaces 24a and 24b. The engagement recess 28 is formed in, for example, an elongated rectangular shape, and extends in a direction perpendicular to the longitudinal direction of the lid 18b. Further, the two engagement recesses 28 are spaced from each other in the longitudinal direction of the lid 18b, and are located at both ends of the bases 22a and 23a in the longitudinal direction. Furthermore, the notch 30 is formed in the longitudinal direction both ends of the bases 22a and 23a, ie, the lower part of the side edge of each short side.

  As shown in FIG. 1 and FIG. 2, in the case 16, the plurality of battery cells 12 are stored in a line with the main surfaces of the outer container 18 facing each other with a predetermined gap. In the present embodiment, the two adjacent battery cells 12 are arranged in a state where they are inverted by 180 degrees so that the positions of the positive electrode terminal 22 and the negative electrode terminal 23 are reversed. That is, the five battery cells 12 are arranged so that the positive electrode terminals 22 and the negative electrode terminals 23 are alternately arranged in two rows along the arrangement direction.

  The upper case 27 is attached to the case main body 26 by covering the case main body 26 in which the battery cells 12 are accommodated from above. As a result, a rectangular box-shaped case 16 is formed as a whole. The upper case 27 has a rectangular plate-like ceiling wall 30 having substantially the same size as the bottom wall of the case body 26. The ceiling wall 30 faces the bottom wall of the case body 26 in parallel and covers the upper portions of the plurality of battery cells 12. The ceiling wall 30 has a plurality of openings 32 and a plurality of exhaust holes 34 through which the positive terminal 22 and the negative terminal 23 of the battery cell 12 are inserted.

  The battery cell 12 accommodated in the case body 26 is in contact with the inner surface of the ceiling wall 30 of the upper case 27, so that the upper end position, in particular, the height positions of the electrode terminals 22 and 23 are determined. The positive terminal 22 and the negative terminal 23 of each battery cell 12 are located in the corresponding openings 32 of the ceiling wall 30. The pressure release valve 24 of each battery cell 12 faces the exhaust hole 34 of the ceiling wall 30.

  As shown in FIGS. 1 and 2, the plurality of battery cells 12 are connected in series by a plurality of bus bars 40. In addition, a bus bar 41 is connected to an electronic cell located at one end of the electronic cell group and a battery cell located at the other end to constitute an output terminal.

  As shown in FIGS. 1 to 3, the bus bar 40 constituting the battery connection structure includes a pair of flat rectangular connection portions 42 and a connection portion 44 that connects the pair of connection portions 42 to each other. It is integrally formed of a conductive material, for example, a metal plate such as aluminum, aluminum alloy, copper, copper alloy, or nickel alloy.

  The pair of connection portions 42 are located at a predetermined interval from each other and aligned in the same plane. The connecting portion 44 that connects the pair of connecting portions 42 is formed by being bent into a substantially U shape, and can be elastically deformed along a longitudinal direction (pitch direction) connecting the pair of connecting portions 42. By the elastic deformation of the connecting portion 44, the interval between the connecting portions 42 can be adjusted to some extent according to the tolerance described later.

  As shown in FIGS. 2 and 3, each connection portion 42 is formed in a rectangular plate shape having a size larger than the joint surface of the positive electrode and negative electrode terminals 22 and 23. The connection portion 42 has a circular probe passage hole 50 formed in the center thereof, a pair of first insertion openings 52 formed through both sides of the probe passage hole, and a pair formed outside the first insertion opening. The second insertion opening 54 is provided. The first insertion opening 52 and the second insertion opening 54 are each formed in, for example, an elongated rectangular shape, and extend in parallel to each other and along the longitudinal direction of the bus bar 40. The pair of first insertion openings 52 are formed at positions and intervals that can face the pair of engagement recesses 28 of the electrode terminal, respectively. The pair of second insertion openings 54 are provided at positions that can face the side edges of the electrode terminals.

  As shown in FIG. 5 and FIG. 6, each connection portion 42 of the bus bar 40 integrally has a pair of engaging convex portions 56 projecting from the back surface thereof. The engaging convex portion 56 is formed in, for example, an elongated rectangular plate shape, and protrudes substantially perpendicularly to the back surface of the connecting portion 42. Further, the pair of engaging convex portions 56 are respectively located in the vicinity of the first insertion opening 52 on both sides of the probe through hole 50, and extend in parallel to each other and along the longitudinal direction of the bus bar 40. Further, the pair of engaging convex portions 56 are provided so as to be able to engage with the engaging recesses 28 of the electrode terminals. Each engagement convex portion 56 is formed to have a length slightly shorter than the engagement recess 28 of the electrode terminal and a thickness (width) equal to or less than half of the width of the engagement recess 28. The protrusion height of each engagement convex portion 56 is formed slightly smaller than the depth of the engagement recess 28. Further, the distance between the pair of engaging convex portions 56 is formed to be substantially equal to the distance between the pair of engaging recesses 28 of the electrode terminal.

  Further, a plurality of engagement protrusions 60 are provided on the side surface extending perpendicularly to the connection portion 42 of each engagement convex portion 56, particularly on the side surface facing in parallel with the other engagement convex portion 56. Yes. These engagement protrusions 60 are, for example, elongated ribs, each extending linearly in a direction substantially perpendicular to the back surface of the connection portion 42 and provided side by side in the longitudinal direction of the engagement protrusion 56. ing. The cross-sectional shape of each rib is formed in, for example, a triangle, a trapezoid, or a semicircle. The engaging protrusion 60 is not limited to the rib shape, and may be a plurality of dot-shaped or island-shaped protrusions.

  As shown in FIGS. 1 to 3, one leaf spring member 62 as a holding member constituting a part of the battery connection structure is provided for one connection portion 42 of the bus bar 40. The leaf spring member 62 is fitted to the connection portion 42 of the bus bar 40 from above, and acts so as to maintain the connection state of the connection portion 42 with respect to the positive electrode and the negative electrode terminals 22 and 23. The leaf spring member 62 is formed by bending an elongated strip-like leaf spring, and is formed by bending a flat flat portion 62a located in the center in the longitudinal direction and a U-shape or V-shape, respectively, on both sides of the flat portion 62a. A pair of pressing convex portions 62b positioned and a pair of engaging end portions 62c bent in an arc shape in the same direction as the pressing convex portions 62b are integrally provided. Further, the width of the leaf spring is formed slightly smaller than the length of the first and second insertion openings 52 and 54 of the bus bar 40.

  The pair of pressing protrusions 62b protrude in the same direction, and are formed at an interval substantially equal to the interval between the pair of first insertion openings 52 formed in the connection portion 42 of the bus bar 40, respectively. Thereby, a pair of press convex part 62b is formed so that engagement with the pair of 1st insertion opening 52 of the connection part 42 and the engagement recess 28 of an electrode terminal is possible, and it can push in.

The pair of engagement end portions 62 c are formed at a distance substantially equal to the distance between the pair of second insertion openings 54 of the connection portion 42. Accordingly, the pair of engaging end portions 62c are formed so as to be able to be inserted into the pair of second insertion openings 54 of the connection portion 42 and to be engaged with the notch 30 of the electrode terminal.
In addition, the leaf | plate spring member 62 should just be able to press and hold | maintain the connection part 42 stably, and can also be formed not only with a metal but with insulating materials, such as a synthetic resin. Moreover, the holding member should just have a spring force, and may be formed not only with a leaf | plate spring but with the other material which has a spring force.

  As shown in FIGS. 1 and 2, the bus bar 41 constituting the positive and negative output terminals includes a rectangular plate-like connecting portion 42 and a plate-like output terminal 63 extending from the connecting portion 42 in a crank shape. And is integrally formed of a conductive material such as aluminum, an aluminum alloy, copper, a copper alloy, or a nickel alloy. A screw hole is formed in the output terminal 63 so that a bolt can be screwed in. The connection part 42 is configured similarly to the connection part 42 of the bus bar 40 described above. Further, the leaf spring member 62 similar to the leaf spring member 62 described above is put on the connection portion 42 of the bus bar 41 from above and is fitted.

  The connection structure having the bus bars 40 and 41 and the leaf spring member 62 configured as described above is connected to the positive terminal 22 and the negative terminal 23 of the battery cell 12 as follows. First, after storing and arranging the five battery cells 12 in the case body 26, the upper case 27 is covered and fixed to the case body 26. Next, as shown in FIGS. 2 and 3, the pair of connection portions 42 of the bus bar 40 are aligned with the positive terminal 22 and the negative terminal 23 of the two adjacent battery cells 12. The connecting portions 42 are respectively disposed on the joining surfaces 24a and 24b of the positive electrode terminal 22 and the negative electrode terminal 23, and the pair of engaging convex portions 56 are pushed into the pair of engaging concave portions 28 of the electrode terminals from above. When the interval between the positive electrode terminal 22 and the negative electrode terminal 23 is slightly deviated due to tolerance or the like, the connecting portion 44 of the bus bar 40 extends or contracts in the longitudinal direction, and the tolerance can be absorbed.

  As shown in FIGS. 7 and 8, the engaging convex portion 56 is pushed into the engaging recess 28 until the lower surface of the connecting portion 42 comes into contact with the joining surfaces 24 a and 24 b of the electrode terminals. By pushing, the engagement protrusions 60 of the respective engagement protrusions 56 slide on the inner surfaces of the engagement recesses 28 and come into close contact with the positive electrode terminal 22 or the negative electrode terminal 23. In the present embodiment, the connection portion 42 is attached to the electrode terminal so that the electrode terminal is sandwiched between the two engagement convex portions 56. Thereby, the connection part 42 fits in the positive electrode terminal 22 or the negative electrode terminal 23, and is mechanically and electrically connected to these electrode terminals. When the engaging protrusion 56 is pushed into the engaging recess 28, the engaging protrusion 60 may be slid while scraping the inner surface of the engaging recess 28, or the engaging protrusion 60 is engaged. You may make it slide, being crushed by the inner surface of a recess.

  Since the engaging convex portions 56 of the connecting portion 42 are formed in a plate shape protruding substantially perpendicularly from the lower surface of the connecting portion 42, when the connecting portion 42 is pressed against the electrode terminals, the pair of engaging convex portions 56 are The engaging protrusions 60 are pressed against the electrode terminals by the elastic force that is elastically deformed in the directions away from each other and the generated elastic force. The pushing load and the resistance value of the connecting portion 42 change depending on the number and width of the engaging protrusions (ribs) 60. The number of ribs can be adjusted according to the required specifications. When the number of the engagement protrusions (ribs) 60 is reduced, the pushing load is reduced and the resistance value is increased.

  As described above, it is desirable that the bus bar 40 be made of a metal material that is softer than the positive electrode and the negative electrode terminals 22 and 23 in order to make the engagement protrusion 60 relatively easy to be crushed. For example, the positive and negative terminals 22 and 23 are made of A3000 series aluminum or A5000 series (A5052) aluminum, and the bus bars 40 and 41 are made of A1000 series aluminum.

After fitting the bus bar connection portion 42 to the positive electrode and the negative electrode terminals 22 and 23 as described above, the leaf spring member 62 is placed on the connection portion 42 of the bus bar 40 from above as shown in FIGS. Fit into the part. At this time, the pair of pressing projections 62 b of the leaf spring member 62 are pushed into the pair of engagement recesses 28 of the electrode terminal through the pair of first insertion openings 52 of the connection portion 42. At the same time, both engagement end portions 62 c of the leaf spring member 62 are pushed through the pair of second insertion openings 54 of the connection portion 42. When the leaf spring member 62 is pushed in until it comes into contact with the upper surface of the connection portion 42, the leading edge of each engagement end portion 62c engages with the notch 30 of the electrode terminal, and the leaf spring member 62 is locked in the pushing position. . The pressing convex portion 62b pushed into the engaging recess 28 is pressed against the inner surface of the engaging recess 28 and the side surface of the engaging convex portion 56, and presses the engaging convex portion 56 from the side to the electrode terminal. , Hold in close contact with the electrode terminal.
In this way, the contact force between the positive or negative electrode terminals 22 and 23 and the bus bar 40 is maintained by attaching the leaf spring member 62 having a spring force to the connecting portion 42 of the bus bar 40 and the positive or negative electrode terminals 22 and 23. Then, the engagement protrusion 60 of the engagement protrusion 56 can be pressed against the inner surface of the recess of the electrode terminal to prevent an increase in electrical resistance. At the same time, it is possible to prevent the bus bar 40 from coming off.
With the above battery connection structure, the electrode terminals 22 and 23 of two adjacent battery cells 12 can be electrically connected to each other.

  Similarly to the bus bar 40, the bus bar 41 constituting the output terminal is fitted into the connecting surface of the positive terminal 22 (or the negative terminal 23) by pressing the connecting part 42 from above, and then the leaf spring member 62 is connected to the connecting part 42. The contact force between the connection terminals 22b and 23b and the bus bar 41 is maintained by fitting from above and locking the connection portion. As a result, the bus bar 41 is electrically and mechanically connected to one electrode terminal 22 (or 23) of the battery cell 12.

  According to the secondary battery device having the battery connection structure configured as described above, the battery cell can be obtained by a simple operation of simply pressing the connection portion 42 and the leaf spring member 62 of the bus bar 40 onto the electrode terminal of the battery cell 12. They can be electrically connected. Thereby, it is not necessary to use bolting or welding of the bus bar, the number of assembling steps can be reduced, and a large facility is not required. Unlike bolt tightening, the tightening torque does not act on the connection terminals, and the battery cells can be connected only by mounting the bus bar and the leaf spring member. Further, unlike the connection by welding, failure due to welding does not occur, and only the bus bar or the leaf spring member needs to be replaced, so that the manufacturing yield is improved.

In the electrical connection using the contact bus bar, even if the connection is electrically stable, there is a possibility that the resistance increases due to a change in time and an environment. According to the secondary battery device according to the present embodiment, the connection portion 42 is pressed by the leaf spring member 62 and pressed against the electrode terminal, thereby preventing stress relaxation and increase in electric resistance. Further, when engaging with the positive and negative terminals 22 and 23, the engaging protrusion 60 of the bus bar 40 comes in contact with the inner surfaces of the engaging recesses of the positive and negative terminals 22 and 23, and at the same time, the engaging protrusion 60 is crushed. Thus, the base material of the connection part 42 is firmly connected to the electrode terminal. Furthermore, the contact force can be maintained by the engagement protrusion 60 being pushed against the inner surface of the engagement recess 28 of the electrode terminal by the leaf spring member 62. Since there is no air layer between the engagement protrusion 60 and the electrode terminals 22 and 23, there is no fear of corrosion such as oxidation, and an increase in resistance due to a change with time or an environment can be prevented.
From the above, a battery connection structure capable of easily and reliably connecting the electrode terminals of the secondary battery, and a secondary battery device including the battery connection structure are obtained. Thereby, a secondary battery device with improved assemblability can be obtained. Furthermore, the protrusion height of the bus bar and the leaf spring member can be reduced with respect to the upper surface (lid 18b) of the battery cell 12. Thereby, it becomes possible to reduce the height dimension of the whole secondary battery apparatus.

  As shown in FIGS. 9 and 10, as in this embodiment, the electrode terminals (the positive terminal 22 and the negative terminal 23) have flat joint surfaces 24 a and 24 b between the pair of engaging recesses 28. In this case, a general welded bus bar 70 can be welded to the joining surfaces 24a and 24b of the electrode terminals. Therefore, the fitting type bus bar or the welded type bus bar according to this embodiment described above can be selected and used for electrical connection between the battery cells.

  Next, a battery connection structure of a secondary battery device according to another embodiment will be described. In other embodiments described below, the same parts as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

(Second Embodiment)
Next, the secondary battery device according to the second embodiment will be described. FIG. 11 is a perspective view showing an arrangement relationship of electrode terminals, bus bars, and leaf spring members of a battery cell in the secondary battery device according to the second embodiment, and FIG. 12 shows a battery cell having electrode terminals according to a modification, and FIG. 13 is an exploded perspective view showing the bus bar, and FIG. 13 is a perspective view showing the back side of the bus bar.

  As shown in FIG. 11, according to the second embodiment, the positive electrode terminal 22 and the negative electrode terminal 23 of the battery cell 12 are one engagement formed at the center of the joint surfaces 24a and 24b of the bases 22a and 23a. A recess 28 is provided. The engagement recess 28 is formed in, for example, an elongated rectangular shape, and extends in a direction orthogonal to the longitudinal direction of the lid 18b of the battery cell 12. Further, notches 30 (shown in FIG. 16) are formed at both ends in the longitudinal direction of the bases 22a and 23b, that is, at the lower portions of the side edges on the respective short sides.

  The engagement recess 28 of the electrode terminal may be formed so as to extend in the longitudinal direction of the lid 18b of the battery cell 12, or as shown in FIG. 12, the direction orthogonal to the longitudinal direction of the lid 18b. The first engagement recess 28a extending in the direction and the second engagement recess extending in the longitudinal direction of the lid 18b may be a cross-shaped engagement recess that intersects at the center.

  As shown in FIGS. 11 to 13, a bus bar 40 as a conductive member constituting the battery connection structure includes a pair of flat rectangular connection portions 42, a connection portion 44 that connects the pair of connection portions 42 to each other, And is integrally formed of a conductive material, for example, a metal plate such as aluminum, aluminum alloy, copper, copper alloy, or nickel alloy.

  The pair of connection portions 42 are located at a predetermined interval from each other and aligned in the same plane. The connecting portion 44 that connects the pair of connecting portions 42 is formed by being bent into a substantially U shape, and can be elastically deformed along a longitudinal direction (pitch direction) connecting the pair of connecting portions 42. By the elastic deformation of the connecting portion 44, the interval between the connecting portions 42 can be adjusted to some extent according to the tolerance described later.

  Each connecting portion 42 is formed in a rectangular plate shape having dimensions larger than the joint surfaces 24 a and 24 b of the positive and negative terminals 22 and 23. The connecting portion 42 has a first insertion opening 52 formed through the central portion thereof, and a pair of second insertion openings 54 formed through both sides of the first insertion opening. The first insertion opening 52 is formed in, for example, an elongated rectangular shape and extends along the longitudinal direction of the bus bar 40. Further, the first insertion opening 52 is formed at a position that can face the engagement recess 28 of the electrode terminal. Each of the second insertion openings 54 is formed in a rectangular shape and opens at the side edge of the connection portion 42. The pair of second insertion openings 54 are respectively provided at positions that can face both side edges of the electrode terminal.

  As shown in FIG. 13 and FIG. 14, each connection portion 42 of the bus bar 40 integrally has a pair of engaging convex portions 56 projecting from the back surface thereof. The engaging convex portion 56 is formed in, for example, an elongated rectangular plate shape, and protrudes substantially perpendicularly to the back surface of the connecting portion 42. The pair of engaging convex portions 56 are positioned along the pair of long sides of the first insertion opening 52, face each other in parallel with the first insertion opening 52 interposed therebetween, and the length of the bus bar 40. It extends along the direction. In addition, the pair of engaging convex portions 56 are provided so as to be able to engage with the engaging recess 28 of the electrode terminal. Each engagement protrusion 56 is formed to have a length slightly shorter than the engagement recess 28 of the electrode terminal and a thickness (width) smaller than half of the width of the engagement recess 28. The protrusion height of each engagement convex portion 56 is formed slightly smaller than the depth of the engagement recess 28.

  A plurality of engaging protrusions 60 project from a side surface extending perpendicularly to the connection portion 42 of each engaging convex portion 56, particularly on the side surface opposite to the other engaging convex portion 56. These engagement protrusions 60 are, for example, elongated ribs, each extending linearly in a direction substantially perpendicular to the back surface of the connection portion 42 and provided side by side in the longitudinal direction of the engagement protrusion 56. ing. The cross-sectional shape of each rib is formed in, for example, a triangle, a trapezoid, or a semicircle. The engaging protrusion 60 is not limited to the rib shape, and may be a plurality of dot-shaped or island-shaped protrusions.

  As shown in FIG. 11, one leaf spring member 62 constituting a part of the battery connection structure is provided for one connection portion 42 of the bus bar 40. The leaf spring member 62 is fitted to the connection portion 42 of the bus bar 40 from above, and acts so as to maintain the connection state of the connection portion 42 with respect to the positive electrode and the negative electrode terminals 22 and 23. The leaf spring member 62 is formed by bending an elongated strip-like leaf spring. The leaf spring member 62 includes a pressing protrusion 62b formed by bending the longitudinal center of the leaf spring into a U shape or a V shape, a flat portion 62a extending on both sides of the pressing protrusion, and a pressing protrusion 62b. And a pair of engagement end portions 62c bent in an arc shape in the same direction. Further, the width of the leaf spring is formed slightly smaller than the length of the first and second insertion openings 52 and 54 of the bus bar 40.

The pressing convex portion 62b is formed so as to be engageable with the first insertion opening 52 of the connecting portion 42 and the engaging recess 28 of the electrode terminal and to be able to be pushed. The pair of engagement end portions 62 c are formed at a distance substantially equal to the distance between the pair of second insertion openings 54 of the connection portion 42. Thus, the pair of engaging end portions 62c are formed so as to be able to be inserted into the second insertion openings 54 of the connection portion 42 and to be engaged with the notches 30 of the electrode terminals.
In addition, the leaf | plate spring member 62 should just be able to press and hold | maintain the connection part 42 stably, and can also be formed not only with a metal but with insulating materials, such as a synthetic resin.

  The connection structure having the bus bar 40 and the leaf spring member 62 configured as described above is connected to the positive terminal 22 and the negative terminal 23 of the battery cell 12 as follows. First, after storing and arranging the five battery cells 12 in the case body 26, the upper case 27 is covered and fixed to the case body 26. Next, as shown in FIG. 11, the pair of connection portions 42 of the bus bar 40 are aligned with the positive electrode terminal 22 and the negative electrode terminal 23 of the two adjacent battery cells 12. The connecting portions 42 are respectively disposed on the joining surfaces 24a and 24b of the positive electrode terminal 22 and the negative electrode terminal 23, and the pair of engaging convex portions 56 are pushed into the engaging recesses 28 of the electrode terminals from above. When the interval between the positive electrode terminal 22 and the negative electrode terminal 23 is slightly deviated due to tolerance or the like, the connecting portion 44 of the bus bar 40 extends or contracts in the longitudinal direction, and the tolerance can be absorbed.

  As shown in FIG. 12, when using an electrode terminal having an engagement recess 28b extending along the longitudinal direction of the lid 18b, the battery cells are arranged so that the side surfaces thereof face each other. Also good. In this case, the bus bar 40 is arranged so that the longitudinal direction thereof coincides with the longitudinal direction of the lid 18b of the battery cell 12, and the pair of connection portions 42 are connected to the positive terminal 22 and the negative terminal of two adjacent battery cells 12. Align with 23. Then, the pair of engaging convex portions 56 are pushed into the engaging recess 28 of the electrode terminal from above.

  As shown in FIGS. 15 and 16, the engaging protrusion 56 is pushed into the engaging recess 28 until the lower surface of the connecting portion 42 comes into contact with the joining surfaces 24 a and 24 b of the electrode terminals. By pushing in, the engagement protrusions 60 of the respective engagement protrusions 56 slide on the inner surface of the engagement recess 28, and are crushed while scraping the inner surface, and are in close contact with the positive electrode terminal 22 or the negative electrode terminal 23. In the present embodiment, the connecting portion 42 is attached to the electrode terminal so that the two engaging convex portions 56 are pressed against two opposing inner surfaces of the engaging recess 28. Thereby, the connection part 42 fits in the positive electrode terminal 22 or the negative electrode terminal 23, and is mechanically and electrically connected to these electrode terminals.

  Since the engaging convex portions 56 of the connecting portion 42 are formed in a plate shape protruding substantially perpendicularly from the lower surface of the connecting portion 42, when the connecting portion 42 is pressed against the electrode terminals, the pair of engaging convex portions 56 are It is elastically deformed in the direction approaching each other, and the engaging protrusion 60 is pressed against the inner surface of the engaging recess 28 by the generated elastic force. The pushing load and the resistance value of the connecting portion 42 change depending on the number and width of the engaging protrusions (ribs) 60. The number of ribs can be adjusted according to the required specifications. When the number of the engagement protrusions (ribs) 60 is reduced, the pushing load is reduced and the resistance value is increased.

  Note that the bus bar 40 is preferably made of a metal material that is softer than the positive electrode and the negative electrode terminals 22 and 23 in order to make the engagement protrusion 60 relatively easy to be crushed. For example, the positive and negative terminals 22 and 23 are made of A3000 series aluminum, and the bus bars 40 and 41 are made of A1000 series aluminum.

After fitting the bus bar connection portion 42 with the positive electrode and the negative electrode terminals 22 and 23 as described above, the leaf spring member 62 is placed over the connection portion 42 of the bus bar 40 from above as shown in FIGS. Fit into the part. At this time, the pressing convex portion 62 b of the leaf spring member 62 is pushed into the engaging recess 28 of the electrode terminal through the first insertion opening 52 of the connecting portion 42. At the same time, both engagement end portions 62 c of the leaf spring member 62 are pushed through the pair of second insertion openings 54 of the connection portion 42. When the leaf spring member 62 is pushed in until it comes into contact with the upper surface of the connection portion 42, the leading edge of each engagement end portion 62c engages with the notch 30 of the electrode terminal, and the leaf spring member 62 is locked in the pushing position. . Further, the pressing projection 62 b pushed into the engagement recess 28 is pushed between the pair of engagement projections 56. Thereby, the pressing convex part 62b press-contacts the side surface of a pair of engaging convex part 56, presses each engaging convex part 56 to an electrode terminal, and hold | maintains the state contact | adhered to the electrode terminal.
In this way, the contact force between the positive or negative electrode terminals 22 and 23 and the bus bar 40 is maintained by attaching the leaf spring member 62 having a spring force to the connecting portion 42 of the bus bar 40 and the positive or negative electrode terminals 22 and 23. Then, the engagement protrusion 60 of the engagement protrusion 56 can be pressed against the inner surface of the engagement recess of the electrode terminal to prevent an increase in electrical resistance. At the same time, it is possible to prevent the bus bar 40 from coming off.
With the above battery connection structure, the electrode terminals 22 and 23 of two adjacent battery cells 12 can be electrically and mechanically connected.

  A connection portion of a bus bar (not shown) constituting the output terminal is configured in the same manner as the connection portion of the bus bar 40 described above. In the second embodiment, the other configuration of the secondary battery device is the same as that of the secondary battery device according to the first embodiment described above.

  According to the secondary battery device having the battery connection structure configured as described above, the battery cell can be obtained by a simple operation of simply pressing the connection portion 42 and the leaf spring member 62 of the bus bar 40 onto the electrode terminal of the battery cell 12. They can be electrically connected. Thereby, it is not necessary to use bolting or welding of the bus bar, the number of assembling steps can be reduced, and a large facility is not required. Unlike bolt tightening, the tightening torque does not act on the connection terminals, and the battery cells can be connected only by mounting the bus bar and the leaf spring member. Further, unlike the connection by welding, failure due to welding does not occur, and only the bus bar or the leaf spring member needs to be replaced, so that the manufacturing yield is improved.

According to the secondary battery device according to the present embodiment, the connection portion 42 is pressed by the leaf spring member 62 and pressed against the electrode terminal, thereby preventing stress relaxation and increase in electric resistance. Further, when engaging with the positive and negative terminals 22 and 23, the engaging protrusion 60 of the bus bar 40 comes in contact with the inner surfaces of the engaging recesses of the positive and negative terminals 22 and 23, and at the same time, the engaging protrusion 60 is crushed. Thus, the base material of the connection part 42 is firmly connected to the electrode terminal. Furthermore, the contact force can be maintained by the engagement protrusion 60 being pushed against the inner surface of the engagement recess 28 of the electrode terminal by the leaf spring member 62. Since there is no air layer between the engagement protrusion 60 and the electrode terminals 22 and 23, there is no fear of corrosion such as oxidation, and an increase in resistance due to a change with time or an environment can be prevented.
From the above, a battery connection structure capable of easily and reliably connecting the electrode terminals of the secondary battery, and a secondary battery device including the battery connection structure are obtained. Thereby, a secondary battery device with improved assemblability can be obtained.

  Further, according to the second embodiment, the leaf spring member can press the two engagement protrusions with one pressing protrusion, and the shape and configuration of the leaf spring member can be simplified. Become. Further, the arrangement direction of the battery cells and the connection direction of the bus bars can be changed according to the direction of the engagement recess provided in the electrode terminal.

Note that the present invention is not limited to the above-described embodiment or modification as it is, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
For example, in the first embodiment described above, the connection portion of the bus bar has a configuration including a pair of first insertion openings and a pair of engagement protrusions. However, the configuration is not limited thereto, and at least one first insertion opening and It is good also as a structure which has one engagement convex part. In this case, the leaf | plate spring member should just have one press convex part.

  The number of secondary battery cells constituting the battery cell group, the shape of the case, the structure, and the like are not limited to the above-described embodiment, and can be appropriately changed as necessary. The bus bar is configured to have a pair of connection portions, but is not limited thereto, and has three or more connection portions and three or more leaf spring members, and is configured to connect three or more electrode terminals. May be.

  The battery cell is not limited to a non-aqueous secondary battery, and various batteries such as an aqueous electrolyte secondary battery or a battery of lead, nickel cadmium, nickel, lithium, lithium air, alkali, or the like can be applied.

10 ... Secondary battery device, 12 ... Battery cell, 16 ... Case, 18 ... Exterior container,
18a ... container body, 18b ... lid, 22 ... positive electrode terminal, 23 ... negative electrode terminal,
22a, 23a ... base, 22b, 23b ... connection terminal, 28 ... engagement recess,
40 ... Bus bar, 41 ... Bus bar (output terminal), 42 ... Connector, 44 ... Connector,
52 ... 1st insertion opening, 54 ... 2nd insertion opening, 60 ... Engagement protrusion, 62 ... Leaf spring member,
62b: Pressing convex portion, 62c: Engaging end portion

Claims (9)

A battery connection structure for connecting an electrode terminal provided in a battery cell and having a joint surface formed with an engagement recess,
A plate-like connecting portion disposed on the joint surface of the electrode terminal, an engaging convex portion protruding from the connecting portion and engaging in an engaging recess of the electrode terminal, and in the vicinity of the engaging convex portion A first insertion opening formed through the connecting portion and facing the engagement recess, and a plate-like conductive member formed of a conductive material;
A holding member having a spring force for engaging with the connection portion and the electrode terminal, wherein the holding protrusion is pushed into the engagement recess of the electrode terminal through the first insertion opening of the connection portion, and the engagement convex portion is moved into the engagement recess. A battery connection structure comprising: a pressing member that presses against the inner surface of the portion; and a holding member that has an engaging end that engages with a side edge of the electrode terminal.   The engaging convex portion of the connecting portion protrudes substantially perpendicularly to the lower surface of the connecting portion, has a side surface facing the inner surface of the engaging recess, protrudes from the side surface, and protrudes from the inner surface of the engaging recess. The battery connection structure according to claim 1, wherein the battery connection structure integrally has a plurality of engaging protrusions that come into contact with each other.   The battery connection structure according to claim 2, wherein the engagement protrusion has a plurality of ribs extending from the vicinity of the base end of the engagement protrusion to a free end.   The connection portion has a second insertion opening facing a side edge portion of the electrode terminal, and an engagement end portion of the holding member engages with a side edge of the electrode terminal through the second insertion opening. Item 4. The battery connection structure according to any one of Items 1 to 3. The electrode terminal of the battery cell has two engagement recesses formed on the joint surface and extending in parallel with a distance from each other,
The connection portion protrudes from the lower surface of the connection portion in the vicinity of the two first insertion openings that respectively face the two engagement recesses, and in the vicinity of the first insertion opening, and the two engagement recesses of the electrode terminal Two engaging projections engaged in the station,
The holding member has two pressing projections that are pushed into the two engagement recesses of the electrode terminal through the first insertion openings of the connection portions and press the engagement projections against the inner surfaces of the engagement recesses. The battery connection structure according to claim 1, wherein the battery connection structure is provided. The connection portion has two engagement protrusions that protrude from the lower surface of the connection portion in the vicinity of the first insertion opening and engage with the engagement recesses of the electrode terminals, respectively. The portions are provided to face each other with the first insertion opening interposed therebetween,
The pressing projection of the holding member is pushed into the engagement recess of the electrode terminal through the first insertion opening, and is pushed between the two engagement projections so that the two engagement projections are pushed into the engagement recess. The battery connection structure according to any one of claims 1 to 4, wherein the battery connection structure is pressed against an inner surface of the place.   The conductive member integrally includes two connection portions each having the same configuration as the connection portion, and a connecting portion that connects the two connection portions to each other, and the two connection portions are in the same plane. The battery connection structure according to claim 1, wherein the battery connection structures are arranged side by side.   The battery connection structure according to claim 1, wherein the holding member is formed of a leaf spring. A plurality of battery cells arranged side by side, each having an electrode terminal having a joint surface formed with an engagement recess;
A case for accommodating the plurality of battery cells;
A battery connection structure for electrically connecting the electrode terminals of the plurality of battery cells,
The battery connection structure includes a plate-like connection portion disposed on a joint surface of the electrode terminal, an engagement convex portion protruding from the connection portion and engaging in an engagement recess of the electrode terminal, and the engagement A plate-like conductive member made of a conductive material, and having an insertion opening formed through the connection portion in the vicinity of the convex portion and facing the engagement recess;
A holding member plate having a spring force that engages with the connection portion and the electrode terminal, and is pushed into the engagement recess of the electrode terminal through the insertion opening of the connection portion, and the engagement convex portion is moved into the engagement recess. A secondary battery device comprising: a pressing member that presses against the inner surface of the electrode member; and a holding member that has an engaging end that engages with a side edge of the electrode terminal.

Images