JP2015185346A - Power storage device and friction build-up method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a contact area between an electrode terminal and a bus bar.SOLUTION: A secondary battery includes an electrode assembly 24 housed in a case 21, and an electrode terminal 31 sending/receiving electricity to and from the electrode assembly 24. The electrode terminal 31 has a plate-like base part 32. A cylindrical pole column part 33 erects from the center of the base part 32. A bus bar is fixed to a front-end surface 36 of the pole column part 33. The front-end surface 36 is subjected to friction build-up with tin, and thereby a build-up layer 51 is formed.

Description

  The present invention relates to a power storage device having an electrode terminal and a friction build-up method.

  A power storage device such as a secondary battery is provided with an electrode terminal for fixing the bus bar. In Patent Document 1, secondary batteries are connected by a bus bar to constitute a battery module.

JP2013-168321A

Incidentally, in order to reduce the contact resistance between the electrode terminal and the bus bar, it is desired to increase the contact area between the electrode terminal and the bus bar.
An object of the present invention is to provide a power storage device and a friction build-up method that can increase the contact area between an electrode terminal and a bus bar.

  A power storage device that solves the above-described problem is a power storage device that includes a metal electrode terminal to which a bus bar is fixed, and the contact surface of the electrode terminal that contacts the bus bar is rubbed by a metal that is softer than the electrode terminal. It has been overlaid.

According to this, by applying friction build-up with a softer metal than the electrode terminal, the bus bar and the electrode terminal are easily brought into close contact with each other, and the contact area between the bus bar and the electrode terminal is increased.
About the said electrical storage apparatus, it is preferable that the said electrode terminal has a recessed part dented from the said contact surface, and has an inclined surface in the surrounding surface of the recessed part which connects the said contact surface and the bottom of the said recessed part.

  According to this, when the friction build-up is performed, the adhesive force with the soft metal becomes higher toward the end of the recess. Since the soft metal provided on the electrode terminal by friction build-up is easy to peel off from the end of the recess, it is possible to suppress the peeling of the soft metal by increasing the adhesion with the soft metal at the end of the recess. it can.

In the power storage device, it is preferable that the bottom surface of the recess and the inclined surface are rough surfaces.
According to this, a soft metal becomes difficult to peel by the anchor effect.
A friction build-up method that solves the above problem is a power storage device by pressing a metal build-up material that is softer than the electrode terminal against a contact surface of a metal electrode terminal that contacts a bus bar while causing friction at the interface. In this method, the dimension between the outer edges of the surface contacting the contact surface of the cladding material is longer than the dimension between the outer edges of the contact surface. .

According to this, since friction build-up can be performed while pressing the build-up material on the entire contact surface, friction build-up can be performed in a short time.
The friction build-up method for solving the above-mentioned problem is that the metal storage electrode device is moved by pressing a metal build-up material softer than the electrode terminal along the contact surface with which the bus bar contacts the metal electrode terminal. A friction build-up method for performing friction build-up on an electrode terminal, wherein the electrode terminal has an insertion hole that is opened in the contact surface and into which a fixture for fixing the bus bar to the electrode terminal is inserted, The dimension between the outer edges of the surface contacting the contact surface of the build-up material is longer than the dimension between the opening edge of the insertion hole and the outer edge of the contact surface, and between the outer edges of the contact surface Shorter than dimensions.

  According to this, the magnitude | size of the build-up material should just be more than the dimension between the opening edge of an insertion hole, and the outer edge of a contact surface, and does not need to be longer than the dimension between the outer edges of a contact surface. For this reason, a build-up material can be made small and the wire supply of a build-up material is attained.

  According to the present invention, the contact area between the electrode terminal and the bus bar can be increased.

The perspective view which fractures | ruptures and shows a part of battery module of embodiment. The perspective view which fractures | ruptures and shows a part of secondary battery of embodiment. Sectional drawing which expands and shows the electrode terminal of the secondary battery of embodiment. Schematic which shows the friction build-up apparatus of embodiment. (A) is a top view which shows the contact surface of the electrode terminal of embodiment, (b) is a top view which shows the end surface of the cladding material of embodiment. The figure which shows the relationship between the electrode terminal of embodiment and the build-up material. The figure which shows the relationship between the electrode terminal of a modification, and build-up material.

Hereinafter, an embodiment of the power storage device will be described.
As shown in FIG. 1, the battery module 10 includes a plurality of secondary batteries 20. Adjacent secondary batteries 20 are connected by a bus bar 11. The bus bar 11 is fixed to the secondary battery 20 with screws 12.

  As shown in FIG. 2, the secondary battery 20 as a power storage device includes a case 21 that forms the outer shape thereof. The case 21 includes a rectangular cylindrical case main body 22 and a rectangular flat plate-like lid body 23 that closes the opening of the case main body 22. The secondary battery 20 includes an electrode assembly 24 housed in a case 21 and an electrode terminal 31 that exchanges electricity with the electrode assembly 24. Two electrode terminals 31 are provided, and are arranged at intervals in the longitudinal direction of the lid body 23. The electrode terminal 31 is a positive electrode terminal and a negative electrode terminal.

  As shown in FIG. 3, the electrode terminal 31 has a plate-like base portion 32. From the center of the base 32, a cylindrical pole column 33 is erected. The pole portion 33 and the base portion 32 are integral and are both made of copper. The pole portion 33 has a male screw portion 34 on the outer peripheral surface. The base portion 32 is located in the case 21, and the pole column portion 33 projects out of the case 21. More specifically, the pole portion 33 projects through the through hole 25 provided in the lid 23 and protrudes outside the case 21, and the nut 35 is screwed into the pole column portion 33 protruding outside the case 21. By joining, it is fixed to the case 21. A cylindrical insulating member 27 is provided between the inner peripheral surface of the through hole 25 and the outer peripheral surface of the pole column portion 33.

  When the base 32 side is the base end and the side opposite to the base 32 is the front end in the axial direction of the polar column portion 33, the polar column portion 33 opens to the distal end surface 36 and extends from the distal end surface 36 toward the base portion 32. An insertion hole 37 is provided. The insertion hole 37 is located on the base end side of the pole column portion 33 with respect to the hexagonal engagement hole 38 that opens in the distal end surface 36 of the pole column portion 33, and communicates with the engagement hole 38. A screw hole 39 is formed. The screw hole 39 has a female screw on the inner peripheral surface. The engagement hole 38 is a hole into which a hexagonal columnar jig is inserted so that the pole column portion 33 and the nut 35 do not rotate when the nut 35 is screwed into the pole column portion 33.

  A concave portion 40 is formed on the distal end surface 36 of the polar column portion 33. The recess 40 extends in an annular shape so as to surround the insertion hole 37. The cross-sectional shape of the recess 40 (the cross-sectional shape in a direction orthogonal to the direction in which the recess 40 extends) is a trapezoid whose bottom 41 is the short side. That is, the peripheral surface connecting the tip surface 36 and the bottom 41 of the recess 40 is an inclined surface 42. The inclination angle θ of the inclined surface 42 is set to 20 degrees to 30 degrees. In addition, the recess 40 has a rough surface with a bottom 41 surface and an inclined surface 42. The rough surface is a lathe formed when the recess 40 is formed by a lathe or a shot blast.

  The tip end surface 36 of the pole portion 33 is friction-filled with tin over the entire surface. As a result, the pole portion 33 has the tin build-up layer 51 over the entire front end surface 36. The overlay layer 51 is also filled in the recess 40.

  When the bus bar 11 is fixed to the secondary battery 20, the bus bar 11 and the tip surface 36 of the pole column 33 are brought into surface contact via the built-up layer 51, and the screw 12 penetrating the bus bar 11 is screwed into the screw hole 39. Match. That is, the contact surface with which the bus bar 11 comes into contact is the tip surface 36 of the pole column portion 33. The bus bar 11 is a plate-like connecting member that can be brought into surface contact with the electrode terminal 31, and is a rectangular flat plate-like connecting member that connects the secondary batteries 20 or a U-shaped flat plate that is attached to the tip of the harness. This includes a metal connection fitting.

Next, a friction build-up method for applying friction build-up to the electrode terminal 31 will be described.
As shown in FIG. 4, a friction build-up device 61 is used when applying friction build-up to the electrode terminal 31.

  The friction build-up device 61 is provided with a table 62 for fixing the electrode terminal 31 and a chuck 64 for fixing the build-up material 63 facing each other. The chuck 64 can be rotated by a motor. Further, the chuck 64 is movable so as to approach and separate from the table 62. When performing friction build-up, the electrode terminal 31 is fixed to the table 62 and the build-up material 63 is fixed to the chuck 64.

  As shown in FIGS. 5A, 5 </ b> B, and 6, the build-up material 63 is tin and has a cylindrical shape. The dimension between the outer edges of the end face of the build-up material 63 is not less than the dimension between the outer edges of the tip face 36 of the electrode terminal 31. In addition, the dimension between the outer edges of each surface is a dimension of the line segment L which passes along the center O in each surface. That is, when the surface is circular, the diameter of the surface is the dimension between the outer edges.

  In the present embodiment, the diameter of the end surface of the build-up material 63 is equal to or larger than the diameter of the front end surface 36 of the electrode terminal 31, and the end surface of the build-up material 63 can cover the entire front end surface 36 of the electrode terminal 31. It has become.

  Then, by rotating the chuck 64, the build-up material 63 is integrally rotated, and by bringing the chuck 64 close to the electrode terminal 31, the build-up material 63 is brought close to the distal end surface 36 of the electrode terminal 31. Go. When the tip surface 36 of the electrode terminal 31 and the end surface of the build-up material 63 come into contact with each other, frictional heat is generated at the interface between the electrode terminal 31 and the build-up material 63 due to the rotation of the build-up material 63. When 63 is pressed against the distal end surface 36 of the electrode terminal 31, a part of the build-up material 63 is plastically pressed against the distal end surface 36 of the electrode terminal 31. At this time, the overlaying material 63 is also filled in the recess 40 of the electrode terminal 31, whereby the overlaying layer 51 is formed on the distal end surface 36 of the electrode terminal 31. Therefore, the surface in contact with the contact surface of the buildup material 63 is the end surface of the buildup material 63.

  When the concave portion 40 is filled with tin, the end of the concave portion 40 has a higher degree of adhesion with tin (the built-up layer 51). Due to the inclined surface 42 of the recess 40, the distance from the build-up material 63 increases as the distance from the end of the recess 40 approaches the bottom 41. For this reason, the pressure to the build-up material 63 increases as the end of the concave portion 40 that is closer to the build-up material 63, and the degree of adhesion with tin increases.

Next, the effect | action of the secondary battery 20 of this embodiment is demonstrated.
When the secondary batteries 20 or between the secondary battery 20 and the load are connected by the bus bar 11, the bus bar 11 is brought into surface contact with the tip surface 36 of the electrode terminal 31 and the screw 12 is screwed into the screw hole 39. At this time, the frictional cladding is applied to the tip surface 36 of the electrode terminal 31 with tin. Tin is a softer metal than copper. That is, the built-up layer 51 is softer than the electrode terminal 31, and compared with the case where the bus bar 11 is fixed to the electrode terminal 31 that is not subjected to friction build-up by tin, the bus bar 11 and the electrode terminal are deformed by the deformation of tin. 31 easily adheres, and the contact area increases.

  Further, in order to provide a metal layer softer than the electrode terminal 31, such as tin, on the tip surface 36 of the electrode terminal 31, the tip surface 36 of the electrode terminal 31 was brought into contact with the molten metal and adhered to the tip surface 36. It is also conceivable to harden the metal. In this case, when the electrode terminal 31 is in contact with the molten metal surface in a tilted state, the thickness of the metal layer after curing may not be constant. In this case, when the bus bar 11 is fixed, the metal layer and the bus bar 11 may not be sufficiently in surface contact, or the contact area may be reduced by attaching the bus bar 11 at an angle.

  As in this embodiment, when the build-up material 63 is pressure-bonded to the tip surface 36 of the electrode terminal 31 at a constant speed by friction build-up, the build-up layer 51 with little thickness deviation can be obtained and melted. The contact area between the bus bar 11 and the electrode terminal 31 can be increased compared to the case where the metal layer is formed by curing the metal.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) The frictional build-up is applied to the tip surface 36 of the electrode terminal 31 with tin. For this reason, when the bus bar 11 is fixed, the build-up layer 51 and the bus bar 11 are easily in close contact with each other, and the contact area between the electrode terminal 31 and the bus bar 11 can be increased. In particular, by providing tin by friction build-up, the build-up layer 51 is less uneven in thickness, and the contact area between the bus bar 11 and the build-up layer 51 can be increased.

  (2) Since the recess 40 has the inclined surface 42, the end of the recess 40 is closer to the tip surface 36. Although the build-up layer 51 is peeled off from the end, the end of the recessed portion 40 is closer to the tip surface 36, so that the pressure when pressing the build-up material 63 is increased toward the end of the recessed portion 40. For this reason, the build-up material 63 filled in the concave portion 40 has a higher adhesion force toward the end of the concave portion 40, and can suppress peeling of the built-up layer 51.

(3) In the recess 40, the surface of the bottom 41 and the inclined surface 42 are rough, the overlay layer 51 is filled into fine irregularities, and the bonding strength of the overlay layer 51 is improved by the anchor effect.
(4) The dimension between the outer edges of the end face of the build-up material 63 is equal to or greater than the dimension between the outer edges of the tip face 36. For this reason, friction build-up can be performed simultaneously on the entire front end surface 36, and the build-up layer 51 can be provided in a short time.

In addition, you may change embodiment as follows.
As shown in FIGS. 5A and 7, the dimension between the outer edges of the end surface of the build-up material 71 is not less than the dimension L2 between the opening edge of the insertion hole 37 and the outer edge of the tip surface 36 of the electrode terminal 31. And may be shorter than the dimension between the outer edges of the tip surface 36 of the electrode terminal 31. In this case, a built-up layer is formed on the distal end surface 36 by moving (revolving) around the insertion hole 37, that is, along the distal end surface 36 while rotating (rotating) the built-up material 71. In this case, since the dimension between the outer edges of the end surface of the cladding material 71 can be shorter than the dimension between the outer edges of the tip surface 36 of the electrode terminal 31, the cladding material 71 having a small diameter can be used. Wire supply becomes possible.

  The electrode terminal 31 may be other than copper, for example, aluminum. Further, the overlay layer 51 may be other than tin as long as it is a soft metal from the electrode terminal 31. For example, when the electrode terminal 31 is copper, it may be aluminum.

The surface of the bottom 41 and the inclined surface 42 of the recess 40 need not be rough.
The electric storage device may be an electric double layer capacitor.
In addition to the cladding material 63, the electrode terminal 31 (table 62) may be rotated in the direction opposite to the rotation direction of the cladding material 63 when applying the friction cladding.

  DESCRIPTION OF SYMBOLS 11 ... Bus bar, 20 ... Secondary battery, 31 ... Electrode terminal, 36 ... Tip surface, 37 ... Insertion hole, 40 ... Recess, 41 ... Bottom, 42 ... Inclined surface, 51 ... Overlay layer, 63, 71 ... Overlay Wood.

Claims (5)

A power storage device including a metal electrode terminal to which a bus bar is fixed,
A power storage device in which a contact surface of the electrode terminal with which the bus bar comes into contact is subjected to friction build-up with a softer metal than the electrode terminal. The electrode terminal has a recess recessed from the contact surface,
The power storage device according to claim 1, wherein an inclined surface is provided on a peripheral surface of the concave portion that connects the contact surface and the bottom of the concave portion.   The power storage device according to claim 2, wherein the bottom surface and the inclined surface of the recess are rough surfaces. Friction that applies friction build-up to the electrode terminal of the power storage device by pressing a metal overlay material softer than the electrode terminal against the contact surface of the metal electrode terminal that contacts the bus bar while causing friction at the interface. A build-up method,
The friction build-up method, wherein a dimension between outer edges of a surface of the build-up material that is in contact with the contact surface is longer than a dimension between outer edges of the contact surface. Friction build-up for applying friction build-up to the electrode terminal of the power storage device by moving while pressing a metal build-up material softer than the electrode terminal along the contact surface of the metal electrode terminal with which the bus bar contacts A method,
The electrode terminal has an insertion hole that is opened in the contact surface and into which a fixture for fixing the bus bar to the electrode terminal is inserted;
The dimension between the outer edges of the surface contacting the contact surface of the build-up material is longer than the dimension between the opening edge of the insertion hole and the outer edge of the contact surface, and between the outer edges of the contact surface Friction build-up method that is shorter than the dimension.