JP2014229564A - Power storage device module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device module in which the contact resistance of both positive electrode terminal and negative electrode terminal with a conductive member can be prevented from increasing, while using a conductive member composed of an aluminum-based metal material.SOLUTION: A battery pack 71 is constituted by connecting the positive electrode terminal 41 and the negative electrode terminal 42 of different secondary batteries 10 with a conductive member 60. The conductive member 60 includes a body 62 made of an aluminum alloy, and has an insertion part 60a penetrating the body 62, and a plating layer 63 formed entirely on the surface of the body 62. The pole 45 of the positive electrode terminal 41 and the conductive member 60 are connected by welding, and the pole 46 of the negative electrode terminal 42 and the conductive member 60 are connected by screwing a fastening member 61 inserted into the insertion part 60a of the conductive member 60 to the female screw part 49a of the negative electrode terminal 42.

Description

  The present invention relates to a power storage device module configured by connecting positive electrode terminals and negative electrode terminals of different power storage devices with a conductive member.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a power storage device module that stores power supplied to an electric motor serving as a prime mover. The power storage device module is configured by electrically connecting electrode terminals of a plurality of secondary batteries with a conductive member for a secondary battery as a power storage device. As a connection method, a structure in which both electrode terminals are screw terminals and a conducting member is fastened with a nut is generally used. In addition, a structure in which one end of the conductive member is fixed to the secondary battery by welding is proposed, for example, one of the positive electrode and the negative electrode terminal is a screw terminal, and the other electrode terminal is a block-shaped terminal, There is a method in which the conducting member is fastened to the screw terminal with a nut and the conducting member is welded to the block-like terminal and connected (for example, see Patent Document 1).

JP 2009-87721 A

  By the way, there is a secondary battery in which the electrode terminal of the positive electrode is made of aluminum and the electrode terminal of the negative electrode is made of copper. In such a secondary battery, when the electrode terminal of the positive electrode is exposed to the atmosphere, an oxide film is easily formed on the surface thereof. In the structure in which the oxide film has low conductivity and the conducting member is fastened with a nut, when such an oxide film is interposed between the electrode terminal and the conducting member, the contact resistance between the electrode terminal and the conducting member increases. . Therefore, the positive electrode terminal is a block-like terminal as in Patent Document 1, the negative electrode terminal is a screw terminal, the conductive member is made of aluminum, and the positive electrode terminal and the conductive member are welded, An increase in contact resistance due to an oxide film on the electrode terminal side of the positive electrode can be suppressed. However, an oxide film is easily formed on the surface of the conductive member made of aluminum, the oxide film is interposed between the electrode terminal of the negative electrode and the conductive member, and the contact resistance between the electrode terminal and the conductive member of the negative electrode is low. It will increase.

  The present invention provides a power storage device module that can prevent an increase in contact resistance between a positive electrode terminal and a negative electrode terminal with a conductive member while using a conductive member made of an aluminum-based metal material. is there.

  In order to solve the above problems, the power storage device module according to claim 1 includes a positive electrode terminal made of an aluminum-based metal material and a negative electrode terminal made of a copper-based metal material, and the positive electrode terminal and the negative electrode A power storage device comprising a plurality of power storage devices in which electrode pole portions provided in electrode terminals protrude from the wall portion of the case, and the positive electrode terminal and the negative electrode terminal of different power storage devices connected by a conductive member In the module, the conducting member includes a main body made of an aluminum-based metal material, and has an insertion portion that penetrates the main body, and at least around the insertion portion on the surface of the main body and the electrode of the negative electrode terminal The contact portion with the column portion has a plating layer, and at least the negative electrode terminal has a screw portion in the pole column portion, and the pole column portion of the positive electrode terminal Is connected by welding to the serial conduction member, said pole portion of the negative electrode terminal and the conductive member is summarized in that connected by screwing the fastening member to the threaded portion.

  According to this, when the positive electrode terminal of the aluminum-based metal material is exposed to the atmosphere, an oxide film is easily formed on the surface, but the pole column portion of the positive electrode terminal and the conductive member are connected by welding. Therefore, the oxide film disappears due to the heat of welding. For this reason, an oxide film is not interposed between the pole part of the welded positive electrode terminal and the conducting member, and the contact resistance between the positive electrode terminal and the conducting member is not increased by the oxide film. Moreover, since the pole part of the positive electrode terminal and the conducting member are the same kind of metal (aluminum metal), welding can be performed easily and reliably.

  On the other hand, in the conductive member, a portion where the plating layer is provided on the surface of the main body is prevented from forming an oxide film by the plating layer. For this reason, when the pole column part of the negative electrode terminal and the conducting member are fastened and connected by a fastening member, no oxide film is interposed between the pole column part of the negative electrode terminal and the contact part of the conducting member, The contact resistance between the negative electrode terminal and the conducting member is not increased by the oxide film.

The aluminum-based metal material includes pure aluminum and an aluminum alloy, and the copper-based metal material includes copper and a copper alloy.
Moreover, about an electrical storage apparatus module, it is preferable that the said conduction | electrical_connection member has a plating layer in the whole surface of the said main body.

According to this, for example, in the main body of the conducting member, the plating layer can be easily formed as compared with the case where the plating layer is formed only in the contact portion with the polar column portion of the negative electrode terminal.
In the power storage device module, the power storage device is a secondary battery.

  ADVANTAGE OF THE INVENTION According to this invention, it can prevent that both the positive electrode terminal and the negative electrode terminal increase the contact resistance with a conduction member, using the conduction member which consists of an aluminum-type metal material.

The disassembled perspective view which shows a battery pack. The perspective view which shows a battery pack. FIG. 3 is a cross-sectional view taken along a line 3-3 in FIG. 2 showing a fastening state between the conductive member and the negative electrode terminal. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2 showing a state in which the conductive member and the positive electrode terminal are welded. (A) And (b) is a perspective view which shows another example of the plating layer in a conduction member.

Hereinafter, an embodiment in which a power storage device module is embodied in a battery pack will be described with reference to FIGS.
As shown in FIG. 1 and FIG. 2, the battery pack 71 is configured by arranging a plurality of secondary batteries 10 as power storage devices in parallel and connecting different secondary batteries 10 in series with a conductive member 60.

  As shown in FIGS. 1, 3, and 4, the secondary battery 10 includes a metal case 12, and an electrode assembly 20 and an electrolytic solution 18 are accommodated in the case 12. The case 12 includes a rectangular parallelepiped case main body 13 having an opening 13 d and a rectangular flat plate-shaped lid 14 that closes the opening 13 d of the case main body 13. The case body 13 and the lid 14 are both made of metal (for example, stainless steel or aluminum alloy), and the case body 13 and the lid 14 are joined by laser welding. Further, the secondary battery 10 of the present embodiment is a square battery whose outer periphery forms a square shape, and is a lithium ion battery that uses a non-aqueous electrolyte as the electrolyte 18.

  The electrode assembly 20 has a laminated structure in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated, and a separator is interposed between the two electrodes. The electrode assembly 20 includes a positive electrode tab group 31 in which positive electrode current collecting tabs 31a included in a plurality of positive electrode electrodes are stacked, and a negative electrode tab group 32 in which negative electrode current collector tabs 32a included in the plurality of negative electrode electrodes are stacked. At least the outermost positive electrode current collecting tab 31 a of the positive electrode tab group 31 is welded to the positive electrode conductive member 33, and at least the outermost negative electrode current collecting tab 32 a of the negative electrode tab group 32 is welded to the negative electrode conductive member 37. .

  As shown in FIGS. 3 and 4, the positive electrode conductive member 33 is welded with a positive electrode terminal 41 made of an aluminum alloy as an aluminum-based metal material, and the negative electrode conductive member 37 is bonded as a copper-based metal material. A copper negative electrode terminal 42 is welded. The positive electrode terminal 41 and the negative electrode terminal 42 exchange electricity with the electrode assembly 20. The positive electrode terminal 41 has a base 43 having a square plate shape, and the negative electrode terminal 42 has a base 44 having a square plate shape. Cylindrical polar column portions 45 and 46 are erected from the center of the base portions 43 and 44 of the positive electrode terminal 41 and the negative electrode terminal 42, and male screw portions 45 a and 46 a are provided on the outer peripheral surfaces of the polar column portions 45 and 46. Have. In addition, when the surface located at the tip in the projecting direction from the lid 14 in each of the pole columns 45 and 46 is an annular tip surface 45f and 46f, the pole column portions 45 and 46 are separated from the tip surfaces 45f and 46f. Female screw holes 48 and 49 that are recessed in a circular hole shape along the axial direction of the pole columns 45 and 46 are provided. The pole portions 45 and 46 have female screw portions 48 a and 49 a as screw portions on the inner peripheral surfaces of the female screw holes 48 and 49.

  In the bases 43 and 44, the surfaces facing the inner surface 14a of the lid 14 are the seating surfaces 43a and 44a, and the surfaces opposite to the seating surfaces 43a and 44a in the thickness direction of the bases 43 and 44 are the assembly side end surfaces 43b and 44b. And A resin terminal cover 50 is attached to the base portions 43 and 44. The terminal cover 50 includes a lid-side insulating plate 51 disposed between the seating surfaces 43 a and 44 a of the base portions 43 and 44 and the inner surface 14 a of the lid 14. The lid-side insulating plate 51 has an insertion portion 51a into which the pole column portions 45 and 46 are inserted. The lid-side insulating plate 51 includes a case-side insulating plate 52 that extends in a direction away from the lid 14 from the side edge of the lid-side insulating plate 51. The case side insulating plate 52 has a rectangular plate shape and extends perpendicularly to the lid side insulating plate 51. In the case-side insulating plate 52, an assembly-side insulating plate 53 extends in the same direction as the lid-side insulating plate 51 and extends along the assembly-side end surfaces 43 b and 44 b at the tip of the case-side insulating plate 52. Yes. The case side insulating plate 52 is formed in a rectangular plate shape.

  The pole column portions 45 and 46 are inserted into the insertion portion 51 a of the lid side insulating plate 51, and the lid side insulating plate 51 surrounds almost the entire circumference of the pole column portions 46 and 46. The lid-side insulating plate 51 is supported on the seating surfaces 43 a and 44 a of the base portions 43 and 44. On the seating surfaces 43 a and 44 a of the base portions 43 and 44, an O-ring 56 is provided so as to surround the pole column portions 45 and 46. The assembly-side insulating plate 53 is disposed closer to the electrode assembly 20 than the assembly-side end faces 43b, 44b of the base portions 43, 44. The assembly-side insulating plate 53 is interposed between the base portions 43 and 44 and the electrode assembly 20.

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

  The pole portions 45 and 46 protrude (expose) the outside of the case 12 through the through hole 14b of the lid 14. Therefore, in this embodiment, the lid 14 constitutes the wall portion of the case 12. The inner peripheral surface of the through-hole 14 b of the lid 14 and the outer peripheral surfaces of the pole columns 45 and 46 are insulated by the insulating member 19. The insulating member 19 includes a tubular portion 24 and a flange portion 25 provided at one end edge in the axial direction of the tubular portion 24. The cylindrical portion 24 is interposed between the inner peripheral surface of the through hole 14 b and the outer peripheral surfaces of the pole column portions 45 and 46. The flange portion 25 is locked around the through hole 14 b on the outer surface 14 c of the lid 14.

  A nut 55 is screwed into the male screw portions 45a, 46a of the pole columns 45, 46. The flange portion 25 of the insulating member 19 is clamped between the outer surface 14 c of the lid 14 and the nut 55, and the nut 55 and the lid 14 are insulated by the flange portion 25. Further, the flange portion 25, the lid 14, the O-ring 56, and the lid-side insulating plate 51 are narrowed between the nut 55 and the base portions 43 and 44, and the positive electrode terminal 41 and the negative electrode terminal 42 are fastened to the lid 14. Has been. In this fastened state, the O-ring 56 is in close contact with the inner surface 14a of the lid 14 and the seating surfaces 43a and 44a of the base portions 43 and 44, and seals the periphery of the through hole 14b.

  As shown in FIG. 1 and FIG. 2, a plurality of secondary batteries 10 have a positive electrode terminal 41, a negative electrode terminal 42 of another adjacent secondary battery 10, and another secondary battery 10 adjacent to a negative electrode terminal 42. A battery pack 71 is constituted by a plurality of secondary batteries 10 connected in series to the positive electrode terminal 41 of the secondary battery 10 via a conducting member 60.

  As shown in FIGS. 1, 3, and 4, the conductive member 60 that electrically connects the secondary batteries 10 includes a main body 62 made of an aluminum alloy as an aluminum-based metal material, and a rectangular main body 62. The plating layer 63 covering the entire surface of the plating layer 63 is made of tin. Tin may also form an oxide film on the surface, but the tin oxide film is easily cracked and easily cracked or peeled off during fastening operations, etc., and has little effect on contact resistance. The conducting member 60 has an insertion portion 60 a penetrating the main body 62 in the thickness direction on one end side in the longitudinal direction, and the periphery and the inner peripheral surface of the insertion portion 60 a of the surface of the main body 62 are covered with the plating layer 63. Yes.

  As shown in FIG. 3, in the battery pack 71, the conducting member 60 is fastened by a fastening member 61 to the pole column portion 46 of the negative electrode terminal 42. The fastening member 61 includes a fastening male screw portion 61a that is screwed into the female screw portion 49a, and a head portion 61b at one end in the axial direction of the fastening male screw portion 61a.

  In the negative electrode terminal 42, one end side in the longitudinal direction (on the insertion portion 60 a side) of the conducting member 60 is supported on the distal end surface 46 f of the pole column portion 46 in a state where the insertion portion 60 a communicates with the female screw hole 49. The fastening male screw portion 61 a of the fastening member 61 inserted through the insertion portion 60 a is screwed into the female screw portion 49 a of the female screw hole 49. The conduction member 60 is sandwiched between the head portion 61 b of the fastening member 61 and the distal end surface 46 f of the pole column portion 46. On the surface of the main body 62, an annular portion around the insertion portion 60 a and facing the tip surface 46 f of the pole column portion 46 is in surface contact with the tip surface 46 f through the plating layer 63, and the negative electrode terminal 42. And the conductive member 60 are electrically connected. Therefore, in the main body 62 of the conducting member 60, a portion surrounding the insertion portion 60 a in an annular shape is the contact portion S.

  As shown in FIG. 4, in the positive electrode terminal 41, the other end side in the longitudinal direction of the conducting member 60 is joined to the distal end surface 45 f of the polar column portion 45 by welding, and welding is performed between the polar column portion 45 and the conducting member 60. Part Y is formed. When welding the positive electrode terminal 41 and the conducting member 60, the plating layer 63 is melted by the heat of welding, the main body 62 and the pole column 45 are joined, and the positive electrode terminal 41 and the conducting member 60 are electrically connected. Connected.

Next, the operation of the battery pack 71 will be described.
The pole portion 45 of the positive electrode terminal 41 and the conducting member 60 are connected by a welded portion Y. Further, the pole portion 46 of the negative electrode terminal 42 and the conducting member 60 are connected by fastening with a fastening member 61.

According to the above embodiment, the following effects can be obtained.
(1) The main body 62 of the conducting member 60 is made of an aluminum alloy, and the pole column 45 of the positive electrode terminal 41 and the conducting member 60 are connected by welding. For this reason, even if an oxide film is formed on the surface of the main body 62, the oxide film and the plating layer 63 disappear due to heat during welding, and even if the conductive member 60 and the positive electrode terminal 41 are made of an aluminum alloy, the positive electrode An oxide film is not interposed between the pole column 45 of the electrode terminal 41 and the conductive member 60, and an increase in contact resistance due to the oxide film can be eliminated.

  On the other hand, in the conductive member 60, a plating layer 63 is provided on the contact portion S in the main body 62, and an oxide film is prevented from being formed on the contact portion S by the plating layer 63. For this reason, an oxide film is not interposed between the pole column part 46 of the negative electrode terminal 42 and the contact part S of the main body 62, and an increase in contact resistance due to the oxide film can be eliminated. Therefore, while using the conductive member 60 made of aluminum alloy, the contact resistance between the positive electrode terminal 41 and the negative electrode terminal 42 with the conductive member 60 does not increase, and the output reduction of the battery pack 71 can be prevented. .

  (2) Since an oxide film is formed on the positive electrode terminal 41 made of aluminum alloy, in order not to intervene between the conductive member 60 and the front end surface 45f of the pole column 45, the pole column 45 It is conceivable to partially provide a plating layer on the front end face 45f. However, in order to partially provide a plating layer, a process such as masking is required in addition to the process of plating itself, which is not preferable because the cost increases. Although it is conceivable to provide a plating layer on the entire surface of the positive electrode terminal 41, if the plating layer contacts the electrolytic solution 18 in the case 12, the electrolytic solution 18 is affected, which is not preferable. In the present embodiment, the positive electrode terminal 41 is not provided with a plating layer, and the conductive member 60 is provided with a plating layer 63. The conducting member 60 has a rectangular plate shape and is provided outside the case 12. For this reason, while preventing the oxide film from being formed by using the plating layer 63, the manufacturing cost is suppressed and the electrolytic solution 18 is not affected.

  (3) The conducting member 60 and the negative electrode terminal 42 are fastened by the fastening member 61. For this reason, it is not necessary to weld the conducting member 60 made of aluminum alloy and the negative electrode terminal 42 made of copper, and the conducting member 60 and the negative electrode terminal 42 can be reliably electrically connected.

  (4) In the conductive member 60, the plating layer 63 is provided on the entire surface of the main body 62. For this reason, compared with the case where the plating layer 63 is provided only in the contact portion S with the pole column portion 46 of the negative electrode terminal 42 in the main body 62 of the conduction member 60, the plating layer 63 can be easily provided and the conduction layer 60 is provided. The manufacturing cost of the member 60 can be suppressed.

  (5) The plating layer 63 is made of tin and can be provided at a low cost. Further, since tin is a metal that is as soft as solder, when the conducting member 60 is pressed against the distal end surface 46f of the pole column portion 46 with the head 61b of the fastening member 61, it is easy to become familiar with the distal end surface 46f. The tip surface 45f can be reliably brought into contact with.

In addition, you may change the said embodiment as follows.
As shown in FIG. 5A, in the main body 62 of the conducting member 60, the plating layer 63 may be provided only on the contact portion S with the tip end face 46f of the polar column portion 46 in the negative electrode terminal 42.

Further, as shown in FIG. 5B, a plating layer 63 may be provided in the main body 62 of the conducting member 60 except for a portion that can be a welded portion Y with the tip surface 45 f of the positive electrode terminal 41.
In the embodiment, the conduction member 60 is supported on the tip surface 46f of the pole column portion 46 in the negative electrode terminal 42, and the fastening member 61 inserted through the insertion portion 60a is screwed into the female screw portion 49a of the pole column portion 46. The fastening method of the negative electrode terminal 42 and the conducting member 60 is not limited to this.

  A support nut is screwed into the male thread portion 46a of the negative electrode terminal 42, and the negative electrode terminal 42 and the support nut are electrically connected. In this case, the support nut constitutes a part of the pole column portion 46. Moreover, the diameter of the insertion portion 60a of the conducting member 60 is increased so that the pole column portion 46 can be inserted. And while inserting the pole part 46 in the insertion part 60a of the conduction member 60, the conduction member 60 is supported on a support nut. Furthermore, a fastening nut as a fastening member is screwed into the male screw portion 46a of the pole column portion 46, the conduction member 60 is sandwiched between the support nut and the fastening nut, the conduction member 60 is fastened to the negative electrode terminal 42, and the electric Connect.

  In this case, in the conductive member 60, the plating layer 63 is provided around the insertion portion 60a and in a contact portion that contacts the support nut. Further, the male screw portion 46a of the pole column portion 46 constitutes a screw portion.

In the positive electrode terminal 41, the female screw hole 48 and the female screw part 48a may be omitted.
The plating layer 63 may be formed of nickel instead of tin.
In the embodiment, the wall portion of the case 12 is embodied as the lid 14, but the side wall or bottom wall of the case body 13 is used as the wall portion of the case 12, and the pole column portions 45 and 46 are protruded from the side wall or bottom wall. May be.

In the electrode assembly 20, the positive electrode current collection tab 31a and the negative electrode current collection tab 32a are good also as a structure which protrudes from the different end surface of the electrode assembly 20, respectively.
The secondary battery 10 is not limited to a lithium ion secondary battery, and may be another secondary battery such as a nickel hydrogen secondary battery or a nickel cadmium secondary battery.

(Circle) the secondary battery 10 does not require electrolyte solution, for example, the separator may be formed with the polymer electrolyte.
The power storage device is not limited to the secondary battery 10 and may be, for example, an electric double layer capacitor or a lithium ion capacitor.

  The electrode assembly 20 does not include the positive electrode conductive member 33 and the negative electrode conductive member 37, the positive electrode tab group 31 is directly welded to the positive electrode terminal 41, and the negative electrode tab group 32 is directly welded to the negative electrode terminal 42. Also good.

  The conducting member 60 is not limited to the one that conducts the secondary batteries 10 in the battery pack 71. For example, the conducting member may be a terminal disposed at the tip of the wiring of the external device, and the same effect can be obtained even in this case.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) The electrical storage device module in which the conducting member has a plating layer only in a contact portion of the surface of the main body with the polar column portion of the negative electrode terminal.

(B) The electrical storage device module in which the conducting member has a plating layer on all of the surface of the main body except the welded portion with the positive electrode terminal.
(C) The screw portion is a female screw portion that is recessed from a distal end surface of the pole column portion in the protruding direction from the wall portion, and the fastening member is inserted into the insertion hole of the conductive member, and the female screw portion A power storage device module screwed into the battery.

  DESCRIPTION OF SYMBOLS S ... Contact part, 10 ... Secondary battery as a power storage device, 12 ... Case, 14 ... Lid as wall part, 41 ... Positive electrode terminal, 42 ... Negative electrode terminal, 45, 46 ... Polar pole part, 49a ... Screw Female thread portion as a portion, 60 ... a conducting member, 60a ... an insertion portion, 61 ... a fastening member, 62 ... a main body, 63 ... a plating layer, 71 ... a battery pack as a power storage device module.

Claims (3)

A plurality of power storage devices, each having a positive electrode terminal made of an aluminum-based metal material and a negative electrode terminal made of a copper-based metal material, in which a pole column provided in the positive electrode terminal and the negative electrode terminal protrudes from a wall portion of the case. And a power storage device module configured by connecting the positive electrode terminal and the negative electrode terminal of different power storage devices with a conductive member,
The conducting member includes a main body made of an aluminum-based metal material, has an insertion portion that penetrates the main body, and is in contact with at least the insertion portion on the surface of the main body and the pole column portion of the negative electrode terminal. Has a plating layer on the part,
At least the negative electrode terminal has a threaded portion in the polar column portion,
The pole column portion of the positive electrode terminal and the conducting member are connected by welding, and the pole column portion of the negative electrode terminal and the conducting member are connected by screwing a fastening member to the screw portion. A power storage device module.   The power storage device module according to claim 1, wherein the conductive member has a plating layer on the entire surface of the main body.   The power storage device module according to claim 1, wherein the power storage device is a secondary battery.