JP2014179197A - Connection structure of secondary battery and secondary battery device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery connection structure capable of connecting the electrode terminal of a battery easily and reliably, and to provide a secondary battery device including the same.SOLUTION: A battery connection structure for interconnecting the electrode terminals of a plurality of battery cells 12 having a columnar electrode terminal 22b, respectively, includes a conductive member 40 formed of a conductive material and having a cylindrical connection 42 to be fitted over the outer peripheral surface of the electrode terminal, and a holding member 52 being fitted to the connection from the outside, and pressing the connection against the outer peripheral surface of the electrode terminal.

Description

  Embodiments described herein relate generally to a connection structure that connects output 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 for connecting the columnar electrode terminals provided in the battery cell has a cylindrical connection portion fitted to the outer peripheral surface of the electrode terminal, and is a conductive member formed of a conductive material. And a holding member that is fitted to the connection portion from the outside and presses the connection portion against the outer peripheral surface of the electrode terminal.

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 and a bus bar of a battery cell of the secondary battery device. FIG. 3 is a side view showing an arrangement relationship before connection of electrode terminals, bus bars, and holder caps of battery cells constituting the connection structure of the secondary battery device. FIG. 4 is a cross-sectional view and a bottom view of the connecting portion of the bus bar. FIG. 5 is a cross-sectional view and a bottom view of the holder cap. FIG. 6 is a cross-sectional view showing a state where the bus bar and the holder cap are connected to electrode terminals. FIG. 7 is a side view showing the connection structure of the secondary battery device according to the second embodiment. FIG. 8 is a cross-sectional view showing a state in which a bus bar and a holder cap are connected to electrode terminals in the second embodiment. FIG. 9 is a side view showing the connection structure of the secondary battery device according to the third embodiment. FIG. 10 is a cross-sectional view showing a state where a bus bar and a holder cap are connected to electrode terminals in the third embodiment.

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 28 are each formed of a synthetic resin having insulation properties, for example, a thermoplastic resin such as polycarbonate (PC) or polyphenylene ether (PPE).

  FIG. 2 is an exploded perspective view showing the electrode terminal portion and the bus bar of the battery cell 12, and FIG. 3 is a side view showing the arrangement relationship before connection of the electrode terminal, bus bar, and holder cap of the battery cell. As shown in FIGS. 1 to 3, 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.

  A positive electrode terminal 22 and a negative electrode terminal 23, which are electrode terminals, are provided at both ends in the longitudinal direction of the lid body 18b and project from 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.

  The positive electrode terminal 22 and the negative electrode terminal 23 of the battery cell 12 include, for example, bases 22a and 23a formed in a stepped rectangular shape, and columnar connection terminals 22b and 23b protruding outward from the upper surface of the base. ing. The base and the connection terminal are integrally formed of a conductive metal such as aluminum or copper. Alternatively, the base and the connection terminal may be formed of other metals and the surface may be plated with gold.

  The connection terminals 22b and 23a are formed in a columnar shape, for example, and extend substantially perpendicular to the lid 18b. Further, a locking engagement groove 25 is formed over the entire circumference at the base end side of the connection terminals 22b and 23b, that is, at the end on the base 22a and 23a side. In addition, the engagement groove | channel 25 should just be formed in the position which the lock claw of the holder cap mentioned later at least can engage, not only the perimeter. The connection terminals 22b and 23b are not limited to a cylindrical shape, and may have other column shapes such as a polygonal column shape and an elliptic column shape.

  As shown in FIG. 1, in the case 16, the plurality of battery cells 12 are stored in a line with the main surfaces of the outer casing 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 28 is covered with the case main body 26 in which the battery cells 12 are accommodated from above, and is attached to the case main body 26. As a result, a rectangular box-shaped case 16 is formed as a whole. The upper case 28 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 28, whereby the upper end position, particularly 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.

4A is a cross-sectional view of the connection portion of the bus bars 40 and 41, and FIG. 4B is a bottom view of the connection portion.
As shown in FIG. 1 to FIG. 3, the bus bar 40 includes a pair of bottomed cylindrical connection portions 42 and a rod-shaped connection portion 44 that connects the pair of connection portions 42 to each other. For example, it is integrally formed of aluminum, aluminum alloy, copper, copper alloy, nickel alloy or the like.

  The pair of connection portions 42 are located at a predetermined distance from each other and the bottom walls are arranged in substantially the same plane. Further, the pair of connection portions 42 are arranged substantially parallel to each other, and the respective lower end openings face the same direction. The bottom wall portions of the pair of connecting portions 42 are connected by a connecting portion 44. The connecting portion 44 is formed to be elastically deformable, and the interval between the connecting portions 42 can be adjusted to some extent according to a tolerance described later.

  As shown in FIGS. 2 to 4, each connecting portion 42 is formed in a bottomed cylindrical shape, here, in a cylindrical shape, a bottom wall 42 a connected to the connecting portion 44, a cylindrical portion, and an open free end. ,have. The connection portion 42 includes a plurality of slits 48 extending from the vicinity of the bottom wall to the free end, and a plurality of engagement protrusions, for example, elongated ribs 50, protruding from the inner peripheral surface.

  The slits 48 extend linearly along the axial direction of the connecting portion 42 and are formed at a predetermined interval along the circumferential direction of the connecting portion 42. Each slit 48 is not limited to the direction parallel to the axis of the connecting portion 42, and may extend obliquely with respect to the axis, or may extend in a curved manner.

  The rib 50 extends linearly along the axial direction of the connecting portion 42. The rib 50 extends from the bottom wall 42 a of the connection portion 42 to the free end of the connection portion 42. The plurality of ribs 50 are provided with at least one rib 50 between two adjacent slits 48. The cross-sectional shape of each rib 50 is formed in, for example, a triangle, a trapezoid, or a semicircle. The lower end of each rib 50, that is, the end located on the free end side of the connecting portion 42 is cut obliquely so that it can be easily fitted to the connecting terminals 22b and 23b. The engagement protrusion is not limited to the rib shape, and may be a plurality of dot-like or island-like protrusions.

  The connection part 42 is formed so as to be engageable with the connection terminals 22 b and 23 b of the battery cell 12. That is, the inner diameter of the cylindrical portion of the connection portion 42 is formed slightly larger than the outer diameter of the connection terminals 22b and 23b. Further, the inner diameter of the connection portion 42 including the protruding height of the rib 50 is formed slightly smaller than the outer diameter of the connection terminals 22b and 23b. By pushing the connection portion 42 around the connection terminals 22b and 23b from the free end (lower end) side, the rib 50 slides on the outer peripheral surface of the connection terminal and is crushed while scraping the outer peripheral surface. It closely adheres to the outer peripheral surfaces of 22b and 23b. Further, in the connection portion 42, the portion located between the adjacent slits 48 is pushed by the connection terminals 22b and 23b and slightly elastically deforms radially outward, and the rib 50 is connected to the connection terminals 22b, 23b by its own elastic force. Press against 23b. Thereby, the connection part 42 fits into the connection terminals 22b and 23b, and is mechanically and electrically connected to the connection terminals.

  Note that the connecting portion 42 is not limited to a cylindrical shape, and may have another cylindrical shape such as a polygonal cylindrical shape or an elliptical cylindrical shape according to the shape of the connection terminal. Further, as described above, in order to make the rib 50 relatively easy to be crushed, it is desirable that the bus bar 40 be made of a metal material softer than the connection terminals 22b and 23b. For example, the connection terminals 22b and 23b are made of A3000 series aluminum or A5000 series (A5052) aluminum, and the bus bar 40 is made of A1000 series aluminum.

  FIG. 5A is a sectional view of a holder cap (spring cap) as a holding member constituting a part of the connection structure, and FIG. 5B is a bottom view of the holder cap. As shown in FIGS. 2, 3, and 5, the holder cap 52 is fitted to the outside of the connection portion 42 of the bus bar 40 and acts to maintain the connection state of the connection portion 42 to the connection terminals 22 b and 23 b. To do. The holder cap 52 is formed, for example, in a cylindrical shape with a bottom, and has a bottom wall 52a, a cylindrical portion, and an open free end. Further, the holder cap 52 has a bottom wall 52a and a part of the cylindrical portion cut along the axial direction to form an opening 54 through which the connecting portion 44 of the bus bar 40 can be inserted.

  The holder cap 52 has a plurality of slits 58 extending from the vicinity of the bottom wall 52a to the free end, and a lock claw 60 protruding from the inner peripheral surface of the free end toward the central axis. The slits 58 extend linearly along the axial direction of the holder cap 52 and are formed at a predetermined interval along the circumferential direction of the holder cap. The interval between the slits 48 is formed so as to substantially coincide with the interval between the slits 48 formed in the connection portion 42 of the bus bar 40. The slit 58 is not limited to the direction parallel to the axis of the connecting portion 42, and may extend obliquely with respect to the axis, or may extend in a curved manner.

  The inner diameter of the holder cap 52 is slightly larger than the outer diameter of the connection portion 42. Thereby, the holder cap 52 can be put on the connection part 42 from above, and can be fitted to the connection part 42 from the outside. The holder cap 52 only needs to be able to stably press and hold the connection portion 42, and is not limited to metal, and can be formed of an insulating material such as synthetic resin. When the holder cap 52 is formed of synthetic resin, the slit 58 may be omitted.

  As shown in FIGS. 1 and 2, the bus bar 41 constituting the positive and negative output terminals includes a bottomed cylindrical connecting portion 42 and a plate-like output terminal extending from the connecting portion 42 in a crank shape. 62, 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 62, and a bolt can be screwed in. In addition, the connection part 42 is comprised similarly to the connection part of the bus bar 40 mentioned above. Further, the connecting portion 42 of the bus bar 41 is fitted with a holder cap 52 similar to the above-described holder cap 52 from above.

  The connection structure having the bus bars 40 and 41 and the holder cap 52 configured as described above is connected to the electrode terminals 22 and 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 28 is covered and fixed to the case body 26. Next, as shown in FIGS. 2 and 3, the bus bar 40 is aligned with the connection terminals 22 b and 23 b of the two adjacent battery cells 12. The connection portions 42 are coaxially arranged above the connection terminals 22b and 23b, respectively, and the two connection portions 42 are pushed into the connection terminals 22b and 23b from above. When the interval between the connection terminals 22b and 23b is slightly deviated due to tolerance or the like, the connecting portion 44 of the bus bar 40 expands or contracts in the longitudinal direction, and the tolerance can be absorbed.

  As shown in FIG. 6, the connecting portion 42 is fitted from the free end (lower end) side to the outer periphery of the connecting terminals 22b and 23b, and the free end of the connecting portion 42 comes to the upper end of the engaging groove 25 of the connecting terminals 22b and 23b. Until the connecting portion 42 is pushed into the connecting terminal. By pushing, the rib 50 slides on the outer peripheral surfaces of the connection terminals 22b and 23b, is crushed while scraping the outer peripheral surface, and is in close contact with the outer peripheral surfaces of the connection terminals 22b and 23b. Thereby, the connection part 42 fits into the connection terminals 22b and 23b, and is mechanically and electrically connected to the connection terminals.

  Since the region between the slits 48 of the connection portion 42 has a wing shape with ribs 50, when it is pushed over the connection terminals 22b and 23b, it is elastically deformed in the radial direction, and the generated elastic force causes ribs. 50 is pressed against the connection terminals 22b and 23b. The pushing load and the resistance value of the connecting portion 42 change depending on the number and width of the ribs 50. The number of ribs can be adjusted according to the required specifications. When the number of ribs 50 is reduced, the indentation load is reduced and the resistance value is increased.

After fitting the connecting portion 42 to the connecting terminals 22b and 23b, as shown in FIGS. 3 and 6, the holder cap 52 is put on the connecting portion 42 of the bus bar 40 from above and fitted to the connecting portion. At this time, the holder cap 52 is oriented so that the connecting portion 44 of the bus bar 40 matches the opening 54 of the holder cap 52, and the holder cap is put on the connecting portion 42. Accordingly, the connecting portion 44 is located in the opening 54 of the holder cap 52, and the holder cap can be attached to the outside of the connecting portion 42. When the holder cap 52 is further pushed in until the free end of the holder cap 52 abuts on the electrode terminal, the lock claw 60 engages with the engagement groove 25 of the connection terminals 22b and 23b, and locks the holder cap 52 in the push-in position. Thereby, the holder cap 52 presses the connection part 42 from the outer peripheral side, and holds the connection terminal 22 in close contact with the connection terminals 22b and 23b. At the same time, the holder cap 52 presses the connection portion 42 from above and prevents the connection portion 42 from coming off from the connection terminals 22b and 23c.
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 connection terminal 22 b or 23 b of the electrode terminal 22 (or 23) by pushing the connection part 42 from above, and then the holder cap 52 is connected to the connection part 42. The contact force between the connection terminals 22b and 23b and the bus bar 41 is maintained by covering the top and locking to the connection terminal. 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 cells can be electrically connected with each other by a simple operation of simply fitting the connection portion 42 of the bus bar 40 to the connection terminal of the battery cell 12. Can be 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 holder cap. Further, unlike the case of connecting by welding, failure due to welding does not occur, and only the bus bar or the holder cap needs to be replaced, so that the manufacturing yield is improved. In addition, when the connection terminals 22b and 23b are formed in a columnar shape and the connection portion 42 of the valve is formed in a cylindrical shape, the connection portion 42 is 360 degrees around the central axis of the connection terminal in any orientation. The connection terminals 22b and 23b can be connected and attached. Therefore, even when the adjacent battery cells 12 are arranged slightly shifted in the width direction, the bus bar 40 can be easily connected to the adjacent connection terminals 22b and 23b.

In the electrical connection by contact type, even if the connection is electrically stable, there is a possibility that the resistance increases due to a change in time and an environmental change. The secondary battery device according to the present embodiment has a structure that prevents stress relaxation and increase in electrical resistance by pressing the connection portion 42 with the holder cap 52 and pressing it against the connection terminal. Further, when engaging with the connection terminals 22b and 23b, the rib 50 of the bus bar 40 comes in contact with the outer peripheral surface of the connection terminals 22b and 23b, and at the same time, the rib 50 is scraped, so that the base material of the connection portion 42 is firmly secured. Conducts to the connection terminal. Furthermore, the wing portion of the connection portion 42, that is, the portion between the slits 48, and the rib 50 are pushed toward the outer peripheral surface side of the connection terminal by the holder cap 52, thereby maintaining the contact force. Since there is no air layer between the rib 50 and the connection terminals 22b and 23b, there is no fear of corrosion such as oxidation, and resistance increase due to time change and environmental change 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.

  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. 7 is a side view showing a positional relationship before connection of electrode terminals, bus bars, and holder caps of battery cells in the secondary battery device according to the second embodiment, and FIG. It is sectional drawing which shows the state in which the holder cap was connected to the electrode terminal.

  As shown in FIGS. 7 and 8, according to the second embodiment, the connection terminals 22 b and 23 b of the electrode terminals 22 and 23 are formed in a cylindrical shape, and further, the extending end peripheral surface is tapered. An inclined surface, that is, a tapered surface 27 is formed. In addition, the base end portion peripheral surfaces of the connection terminals 22b and 23b on the bases 22a and 23a side are formed in a tapered surface 29 that tapers toward the base. An engagement groove 25 is formed by the tapered surface 29. In the second embodiment, the other configuration of the secondary battery device is the same as that of the first embodiment described above.

  As shown in FIG. 6, when the connection portion 42 of the bus bar 40 is fitted to the connection terminals 22b and 23b from above, the ribs 50 of the connection portion 42 slide on the outer peripheral surfaces of the connection terminals 22b and 23b, The contact terminals 22b and 23b are crushed while being scraped, and are brought into close contact with the outer peripheral surfaces and the tapered surfaces 27 of the connection terminals 22b and 23b. Thereby, the connection part 42 fits into the connection terminals 22b and 23b, and is mechanically and electrically connected to the connection terminals. Further, the connection portion 42 is fitted with a holder cap 52, and the connection portion 42 is pressed toward the connection terminal by the holder cap, and the connection state of the connection portion 42 is maintained. Further, the holder cap 52 is locked in the pushing position by the lock claw 60 to prevent the connection portion 42 from coming off and poor connection.

  According to the second embodiment, by providing the tapered surface 27 on the connection terminals 22b and 23b, the rib 50 comes into contact with the tapered surface, and the contact area between the connection terminal and the rib increases. Thereby, a connection terminal and a connection part can be electrically connected more reliably, and the increase in electrical resistance can be prevented. In addition, also in 2nd Embodiment, the effect similar to 1st Embodiment mentioned above can be acquired.

(Third embodiment)
Next, a secondary battery device according to a third embodiment will be described. FIG. 9 is a side view showing an arrangement relationship before connection of electrode terminals, bus bars, and holder caps of battery cells in the secondary battery device according to the third embodiment, and FIG. It is sectional drawing which shows the state in which the holder cap was connected to the electrode terminal.

  As shown in FIGS. 9 and 10, according to the third embodiment, a recess, for example, a circular recess 31 is formed in the bases 22a and 23a of the electrode terminals 22 and 23, and the bottom of the recess is formed. The cylindrical connection terminals 22b and 23b are erected. The heights of the connection terminals 22b and 23b are set to be substantially the same as the depth of the recess 31, and the extension ends of the connection terminals are located on substantially the same plane as the surfaces of the bases 22a and 23a. Further, the periphery of the connection terminals 22b and 23b is surrounded by an annular recess 31. In the third embodiment, the other configuration of the secondary battery device is the same as that of the first embodiment described above, and the same reference numerals are given to the same portions, and detailed description thereof is omitted. .

  As shown in FIG. 10, when the connecting portion 42 of the bus bar 40 is fitted to the connecting terminals 22b and 23b from above, the rib 50 of the connecting portion 42 slides on the outer peripheral surfaces of the connecting terminals 22b and 23b, Is crushed while scraping off, and is in close contact with the outer peripheral surfaces of the connection terminals 22b and 23b. Further, the end portion on the free end side of the connecting portion 42 is located in the recess 31 of the electrode terminal. Thereby, the connection part 42 fits into the connection terminals 22b and 23b, and is mechanically and electrically connected to the connection terminals. Further, the connecting portion 42 is fitted with the holder cap 52, and is pushed into the electrode terminal side to engage the lock claw 60 with the engaging groove of the connecting terminal. At this time, the free end (lower end) of the holder cap 52 is located in the recess 31 of the electrode terminal. The connection part 42 is pressed toward the connection terminals 22b and 23b by the holder cap 52, and the connection state of the connection part 42 is maintained. Further, the holder cap 52 is locked in the pushing position by the lock claw 60 to prevent the connection part 42 from coming off and poor connection.

  According to the third embodiment, with respect to the upper surface (lid 18b) of the battery cell 12, the protruding heights of the connection terminals 22b and 23b and the protruding heights of the valve and the holder cap connected to the connection terminals Can be lowered. Thereby, the height dimension of the whole battery module can be reduced. In addition, also in 3rd Embodiment, the effect similar to 1st Embodiment mentioned above can be acquired.

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, the shape of the connection portion of the bus bar and the electrode terminal is not limited to the cylindrical shape or the columnar shape, and may be other shapes. That is, the connection portion and the connection terminal of the electrode terminal may be in a shape that can be engaged with each other. 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 connecting portions, but is not limited thereto, and has three or more connecting portions and three or more holder caps, and is configured to connect three or more electrode terminals. Also good.

  Further, 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, 25 ... engagement groove,
27 ... Taper surface, 31 ... Recess, 40 ... Bus bar, 41 ... Bus bar (output terminal),
42 ... connecting portion, 44 ... connecting portion, 48 ... slit, 50 ... rib,
52 ... Holder cap (holding member), 58 ... Slit, 60 ... Lock claw

Claims (10)

A battery connection structure for connecting columnar electrode terminals provided in a battery cell,
It has a cylindrical connection portion that fits on the outer peripheral surface of the electrode terminal, and is fitted from the outside to the conductive member formed of a conductive material, and the connection portion is connected to the outer peripheral surface of the electrode terminal. A battery connection structure comprising: a holding member to be pressed.   The connection portion includes a slit extending from the vicinity of the proximal end of the connection portion to a free end, and an engagement protrusion that protrudes from the inner peripheral surface of the connection portion and contacts the outer peripheral surface of the electrode terminal. The battery connection structure according to claim 1.   The battery connection structure according to claim 2, wherein each of the engagement protrusions has a plurality of ribs extending from the vicinity of the proximal end of the connection portion to a free end.   4. The battery connection structure according to claim 3, wherein the plurality of ribs extend along an axial direction of the connection portion and are provided at intervals in a circumferential direction of the connection portion. The connecting portion has a plurality of slits provided at intervals in the circumferential direction,
The battery connection structure according to claim 4, wherein the engagement protrusion is provided in a region between the slits in the connection portion.   6. The conductive member according to claim 1, wherein the conductive member integrally includes the two connecting portions positioned with a gap therebetween and a connecting portion that connects the two connecting portions to each other. Battery connection structure.   The battery connection structure according to any one of claims 1 to 6, wherein the holding member has a bottomed cylindrical shape and is fitted on an outer periphery of the connection portion so as to cover the connection portion from above.   The battery connection structure according to claim 7, wherein the electrode terminal has an engagement groove formed on a peripheral surface, and the holding member has a lock claw that engages with the engagement groove.   9. The battery connection structure according to claim 1, wherein the electrode terminal has a tapered surface provided on an outer periphery of an extended end, and the connection portion abuts on the tapered surface. A plurality of battery cells each having a columnar electrode terminal and arranged side by side;
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 has a cylindrical connection portion that fits to the outer peripheral surface of the electrode terminal, and is fitted from the outside to the conductive member formed of a conductive material, and the connection portion is connected to the connection portion. A secondary battery device comprising: a holding member that presses against an outer peripheral surface of the electrode terminal.

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