JP2009087707A - Cell terminal structure, connection structure between cell terminals, and cell terminal manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to easily carry out laser butt welding between an end face of a cell terminal and a protruded face of an outer package can and jointing of a connecting bar between cell terminals, as well as improve its joint reliability. <P>SOLUTION: The cell terminal 14 is made by forming at least one terminal in a rectangular parallelepiped block, and jointing it with one face of an outer package can 12 forming a box-like cell. The connecting structure between the cell terminals connects between a plurality of cell terminals 14 with a connecting bar 18 with holes formed larger than tips of the cell terminals 14. Further, in the cell terminal manufacturing method, at least one terminal is formed in a block, and in forming cell terminals in the outer package can by connecting the terminals to the outer package can of the box-like cell, a cap body of the outer package can and the terminals are jointed, then, a lead plate housed in the outer package can and the cap body are jointed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cell terminal structure of a box-shaped cell of a secondary battery, a connection structure between cell terminals, and a cell terminal manufacturing method.

  In general, in a secondary battery cell using a plurality of box-shaped cells, a terminal is provided in the box-shaped cell, and for connection with other secondary battery cells, a battery pack is formed by connecting the cell terminals with connection conductors. ing. For example, as a battery pack installed in an electric / electronic device designed and manufactured to be small and light in consideration of portability and portability, the built-in electric circuit generates heat or the ambient temperature of the battery cell rises due to overcharging. However, there is one that can suitably prevent a fire due to the evaporation gas of the electrolytic solution (see, for example, Patent Document 1).

Also, as applied to battery box devices for electric vehicles, a breaker device consisting of a breaker that cuts off the driving power supply is housed in the battery box, and the battery voltage check of the electric vehicle battery box device alone, the operation of the breaker In some cases, performance can be confirmed and mounting and maintenance on a vehicle can be performed efficiently (for example, see Patent Document 2).
Japanese Patent No. 3014293 Japanese Patent No. 3350189

  However, in the conventional case, when attaching the cell terminal of the battery cell to the cell outer can, the cell terminal is attached to the cell outer can by laser butt welding, but a laser leaks on the outer can side and a hole is opened in the outer can. There is. Further, when connecting the battery cells, the cell terminals are connected by a connection bar, but an extra force may be applied to the cell terminals or a crack may be generated during laser butt welding.

  An object of the present invention is to provide a cell terminal structure and a cell in which laser butt welding between the end surface of the cell terminal and the protruding surface of the outer can and the connection bar between the cell terminals can be easily performed and the bonding reliability can be improved. It is to provide an inter-terminal connection structure and a cell terminal manufacturing method.

  The invention relating to the cell terminal structure of the present invention is characterized in that at least one terminal is formed of a substantially rectangular parallelepiped block and joined to one surface of an outer can forming a box-shaped cell. The inter-cell terminal connection structure of the present invention is characterized in that the terminals of a plurality of cells are connected by a connection bar in which a hole larger than the tip shape of the terminal of the cell terminal structure is formed. Furthermore, in the cell terminal manufacturing method of the present invention, at least one terminal is formed as a block, and the formed terminal is connected to an outer can of a box-shaped cell to form a cell terminal on the outer can. And a terminal, and thereafter, a lead plate and a cap body housed in the outer can are joined.

  ADVANTAGE OF THE INVENTION According to this invention, the laser butt welding between the end surface of a cell terminal and the projection surface of an exterior can and the joining of the connection bar between cell terminals can be performed easily, and joining reliability can be improved.

  FIG. 1 is a configuration diagram of a cell terminal structure according to an embodiment of the present invention. FIG. 1 (a) is a side view of the cell terminal structure viewed from the side of the battery cell, and FIG. 1 (b) is an upper surface of the battery cell. FIG. 1C is an enlarged view of the cell terminal structure viewed from the side surface of the battery cell.

  As shown in FIG. 1A, a cap body 13 is provided on the top of the outer can 12 of the battery cell 11, and a pair of positive and negative cell terminals 14 is provided on the cap body 13. The cell terminal 14 is formed of a substantially rectangular parallelepiped block, and is joined to one surface of the cap body 13 of the outer can 12 that forms a box-shaped cell. The cell terminal 14 has a wide surface that contacts the surface of the cap body 13 of the outer can 12, and is formed into a convex rectangular parallelepiped that gradually narrows toward the tip. In FIG. 1, the cell terminals 14 are shown in which rectangular parallelepiped blocks are stacked in three stages.

  That is, as shown in FIGS. 1B and 1C, the cell terminal 14 is formed by stacking rectangular parallelepiped blocks in three stages. The cap body 13 of the outer can 12 is provided with a convex protrusion 15 at a position facing the end face of the lowermost block forming the cell terminal 14. This facilitates the mounting of the cell terminal 14 to the cap body 13. The concave portion 16 in FIG. 1C is a concave portion generated by press working when the convex protrusion 15 is formed on the cap body 13.

  The cell terminal 14 is joined to the cap body 13 by laser butt welding. That is, in a state where the cell terminal 14 is locked by the convex protrusion 15 of the cap body 13, the contact surface of the lowermost block convex protrusion 15 of the cell terminal 14 is laser-welded. Thereby, the laser welding part 17 is formed.

  In this way, since the end face of the cell terminal 14 and the surface of the convex protrusion 15 of the outer can 12 are formed at opposite positions, butt welding by a laser is facilitated and the joining reliability is increased. In addition, since the cell terminal 14 is formed into a narrow convex rectangular parallelepiped stepwise toward the tip, the laser can be prevented from leaking to the cap body 13 side of the outer can 12 when performing laser butt welding. It is possible to avoid an influence such as a hole being formed in the 12 cap bodies 13. Further, the butt joint between the cell terminal 14 and the cap body 13 of the outer can 12 is facilitated.

  FIG. 2 is a configuration diagram of a connection structure between cell terminals according to an embodiment of the present invention. FIG. 2A is a top view of the cell terminal connection structure as viewed from the top surface of the battery cell, and FIG. FIG. 1C is a side view of the cell terminal connection structure viewed from the side of the battery cell.

  When connecting a plurality of battery cells 11, a plurality of cell terminals 14 are connected by a connection bar 18. FIG. 2A shows a case where two cell terminals 14 are connected by a connection bar 18. A hole 19 larger than the tip shape of the cell terminal 14 is formed in the connection bar 18, and a block at the tip portion of the cell terminal 14 is inserted into the hole 19. Since the hole 19 larger than the tip shape of the cell terminal 14 is formed, a fixing error of the plurality of cell terminals 14 can be absorbed when the plurality of cell terminals 14 are joined. Further, since the cell terminal 14 is formed into a narrow convex rectangular parallelepiped stepwise toward the tip, the cell terminal 14 protruding from the outer can 12 of the battery cell 11 can be enlarged, and the connection bar 18 between the cell terminals is joined. Easy to do.

  Next, as shown in FIG. 2B, the connection bar 18 is formed by bending a substantially central portion into a convex shape. Thereby, the rigidity of the connection bar 18 for connecting the inter-cell terminals is softened, and the force applied to the cell terminals 14 can be reduced. In addition, the connection bar 18 and the cell terminal 14 are joined by continuous wave laser welding between the cell terminal 14 and the connection bar 18. Thereby, in joining between the cell terminal 14 and the cap body 13 of the outer can 12, and between the cell terminal 14 and the connection bar 18, when these materials are pure aluminum such as A1050 and aluminum alloy such as A3003 and A5052. , And pure aluminum such as A1050 and an aluminum alloy such as A3003 and A5052 can be joined without cracking.

  Next, the cell terminal manufacturing method according to the embodiment of the present invention will be described. FIG. 3 is an explanatory view showing an example of a cell terminal structure manufactured by using the cell terminal manufacturing method of the present invention. FIG. 3 (a) is a side view of an example of the cell terminal structure, and FIG. It is detail drawing of A1 part of 3 (a). The cap body 13 is provided with a pair of positive and negative cell terminals 14a and 14b. A1 portion is a positive cell terminal 14a. The cell terminals 14a and 14b are joined to the cap body 13 by laser butt welding, respectively. At that time, the negative cell terminal 14 b is joined to the cap body 13 via the insulator 20. This is to prevent the positive cell terminal 14 a and the negative cell terminal 14 b from being short-circuited via the cap body 13.

  Then, the lead plate 21 is laser butt welded to the cap body 13. Also in this case, the lead plate 21 is joined to the cap body 13 via the insulator 20 on the negative electrode side. The lead plate 20 is a member for connecting the cell terminals 14a and 14b to a conductor housed in the outer can of the battery cell.

  As shown in FIG. 3 (b), the cell terminal 14a of the positive electrode is formed into a convex rectangular parallelepiped having a wide surface side in contact with the surface side of the cap body 13 and gradually narrowing toward the tip. In FIG.3 (b), the cell terminal 14a has shown the thing of a rectangular parallelepiped block piled up in three steps. Then, the lowermost block of the cell terminal 14a is inserted into the recess provided in the cap body 13, and the cell terminal 14a is attached to the cap body 13 and laser-welded in this state.

  Thereby, the ligament of the cap body 13 can be secured, positioning in two directions can be facilitated, and the joining reliability at the time of fixing can be improved. Laser welding can be used for continuous oscillation or pulse oscillation.

  FIG. 4 is an explanatory view showing another example of the cell terminal structure manufactured by using the cell terminal manufacturing method of the present invention, FIG. 4 (a) is a side view of another example of the cell terminal structure, and FIG. FIG. 4B is a detailed view of a portion A2 in FIG. The difference from the example shown in FIG. 3 is that when the cell terminal 14 is mounted on the cap body 13, a convex protrusion 15 is provided on the cap body 13 instead of the concave portion of the cap body 13. That is, the cell terminal 14 is attached to the convex protrusion 15 provided on the cap body 13 in the same manner as shown in FIGS. Reference numeral 16 denotes a concave portion generated when the convex protrusion 15 is pressed.

  Also in this case, the cap body 13 and the cell terminal 14 are joined, and then the lead plate 21 and the cap body 13 housed in the outer can are joined by laser welding.

  Here, the cell terminal 14 is made of, for example, an aluminum alloy (No. A3000) or pure aluminum Al (No. A1000) material, and the lead plate 21 is made of pure aluminum Al (No. A1000) material. Thereby, the electrical conductivity and manufacturability of the cell terminal 14 can be improved.

  FIG. 5 is an explanatory diagram of laser welding of the cell terminal structure shown in FIG. First, the cell terminals 14a and 14b are joined to the cap body 13 in advance by laser welding. Then, as shown in FIG. 5A, the cell terminals 14a and 14b are set downward and set on the welding jig 22. The welding jig 22 holds the tip portions of the cell terminals 14 a and 14 b and a part of the cap body 13 with a spring 24 via a cooling plate 23. Further, a cooling plate (for example, a copper plate) 23 is set on a part of the cap body 13 as necessary.

  In this state, the laser beam 26 is irradiated from the nozzle 25, and laser welding is performed from the opposite side (lead plate 21 side) of the laser welding portion 17a between the cell terminal 14 and the cap body 13 as shown in FIG. Then, the lead plate 21 is joined to the cap body 13. Then, as shown in FIG. 5 (c), the laser welded portion 17b from the lead plate 21 side and the laser welded portion 17a from the cell terminal 14 side face each other, as shown in FIG. 5 (d). Then, laser welding is performed until the laser welded portion 17b from the lead plate 21 side and the laser welded portion 17a from the cell terminal 14 side are integrated.

That is, the lead plate 21 and the cell terminal 14 are joined by a laser welding with a penetration depth of 1.0 to 1.9 mm. In this case, for example, the laser welding conditions are set as follows.
Laser output: 700W to 2000W
Welding speed: 700 mm / min to 3000 mm / min Shielding gas flow rate: 10 to 100 l / min Laser irradiation spot diameter: 0.05 mm to 0.3 mm
Laser incident angle: ± 30 ° from the surface
Thereby, the laser welding part 17 which makes the penetration depth to the total plate thickness of the lead plate 21 and the cap body 13 can be formed.

  In the above description, the cap body 13 and the cell terminal 14 are previously joined by laser welding, and then the cap body 13 and the lead plate 21 are joined by laser welding. The plate 21 and the cap body 13 may be joined at a time by laser welding. In this case, the three members of the cell terminal 14, the lead plate 21, and the cap body 13 can be fixed by laser welding in one step.

  FIG. 6 is an explanatory diagram of laser welding of the cell terminal structure shown in FIG. Also in this case, as in the case of FIG. 5, the cell terminals 14a and 14b are joined to the cap body 13 by laser welding in advance, and the cell terminals 14a and 14b are directed downward as shown in FIG. Set on welding jig 22.

  The difference from the case of FIG. 5 is that the concave portion 16 is formed by press working when the convex protrusion 15 is formed on the cap body 13. Since this concave portion 16 is present, it is impossible to perform laser welding by facing the cell terminal 14 and the cap body 13 from the opposite side of the laser welded portion 17a (lead plate 21 side), so that the position is shifted from the position of the laser welded portion 17a. Laser welding is performed on the position, and the lead plate 21 is joined to the cap body 13. Therefore, unlike the case of FIG. 5, the laser welded portion 17a and the laser welded portion 17b are not integrated.

  According to the embodiment of the present invention, since the cell terminal 14 is formed by a substantially rectangular parallelepiped block and joined to one surface of the cap body 13 of the outer can 12, the cell terminal 14 protruding from the outer can 12 can be enlarged, and the cell terminal The connection bars 18 between the 14 can be easily joined. In addition, since the protrusions and recesses to be attached to the end face of the cell terminal 14 and the surface of the outer can 12 are provided, the cell terminal 14 can be attached to the outer can 12 with high accuracy, and butt welding with a laser is facilitated and the joining reliability is increased. Therefore, when performing laser butt welding, it is possible to avoid the influence of a laser leaking on the outer can side and a hole opening in the outer can.

  Moreover, since pure aluminum, such as A1050, and aluminum alloys, such as A3003 and A5052, are used as the material for the cell terminal, the outer can, and the connection bar, it is possible to join these without cracking.

The block diagram of the cell terminal structure concerning embodiment of this invention. The block diagram of the connection structure between cell terminals concerning embodiment of this invention. Explanatory drawing which shows an example of the cell terminal structure manufactured using the cell terminal manufacturing method of this invention. Explanatory drawing which shows another example of the cell terminal structure manufactured using the cell terminal manufacturing method of this invention. Explanatory drawing of the laser welding of the cell terminal structure shown in FIG. Explanatory drawing of the laser welding of the cell terminal structure shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Battery cell, 12 ... Exterior can, 13 ... Cap body, 14 ... Cell terminal, 15 ... Convex protrusion, 16 ... Recessed part, 17 ... Laser welding part, 18 ... Connection bar, 19 ... Hole, 20 ... Insulator, 21 ... Lead plate, 22 ... Welding jig, 23 ... Cooling plate, 24 ... Spring, 25 ... Nozzle, 26 ... Laser beam

Claims (12)

  A cell terminal structure in which at least one terminal is formed of a substantially rectangular parallelepiped block and joined to one surface of an outer can forming a box-shaped cell.   The cell terminal structure according to claim 1, wherein a convex protrusion is provided on one surface of the outer can so as to face an end surface forming the terminal.   2. The cell terminal structure according to claim 1, wherein a surface side of the terminal that contacts the box-shaped cell surface side is formed into a convex rectangular parallelepiped that is wide and gradually narrows toward the tip.   The cell terminal structure according to any one of claims 1 to 3, wherein the terminal and the outer can are joined by continuous-wave laser welding.   A cell characterized in that the terminals of a plurality of cells are connected by a connection bar in which a hole larger than the tip shape of the terminal of the cell terminal structure according to any one of claims 1 to 4 is formed. Terminal connection structure.   The inter-cell terminal connection structure according to claim 4, wherein a substantially central portion of the connection bar is bent and formed into a convex shape.   The cell terminal connection structure according to claim 5 or 6, wherein the terminal and the connection bar are joined by continuous wave laser welding.   In the cell terminal manufacturing method in which at least one terminal is formed as a block, and the formed terminal is connected to an outer can of a box-shaped cell to form a cell terminal on the outer can, the cap body and the terminal of the outer can A cell terminal manufacturing method comprising: joining, and thereafter joining the lead plate and the cap body housed in the outer can.   9. The cell terminal according to claim 8, wherein the terminal is made of an aluminum alloy (A3000) or pure aluminum Al (A1000), and the lead plate is made of a pure aluminum Al (A1000) material. Production method.   The cell terminal manufacturing method according to claim 8, wherein a concave portion is provided on one surface of the outer can so as to face an end surface forming the terminal.   The method of manufacturing a cell terminal according to claim 8, wherein the terminal, the lead plate, and the cap body are joined by laser welding at a time.   The cell terminal manufacturing method according to claim 8, wherein the lead plate and the terminal are joined by laser welding, and a penetration depth is 1.0 to 1.9 mm.

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