JP2015065066A - Assembly structure of a plurality of square type power storage devices - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an assembly structure of a plurality of square type power storage devices in which a bus bar and an electrode terminal can be connected in an excellent state from electrical and mechanical point of views.SOLUTION: Electrode terminals protruding from a body part of a secondary battery are connected by a bus bar 30 and are coupled to the electrode terminals protruding from the body part of another secondary battery. The electrode terminals 22, 23 have grooves 63, 64 opened to the surface in contact with the bus bar 30. The bus bar 30 has projections 33, 34 which are formed on the surface 31a in contact with the electrode terminals 22, 23 and inserted into the grooves 63, 64. The projections 33, 34 have irregularities 35 on the surface of a portion in contact with the inner surface of the grooves 63, 64.

Description

  The present invention relates to an assembly structure of a plurality of prismatic power storage devices.

  A technique is known in which one end of a bus bar is fastened to the electrode terminal of one secondary battery and the other end of the bus bar is fastened to the electrode terminal of the other secondary battery in order to electrically connect the secondary batteries with the bus bar. (For example, Patent Document 1).

JP 2012-28061 A

  If the electrical connection between the bus bar and electrode terminals is poor in the assembly of multiple prismatic power storage devices, there is energy loss due to an increase in electrical resistance, and the energy of the secondary battery can be efficiently transmitted to a load such as a motor. Can not. In addition, there is a demand to connect the bus bar and the electrode terminal in a mechanically good state.

  The objective of this invention is providing the assembly | attachment structure of the some square-shaped electrical storage apparatus which can connect a bus-bar and an electrode terminal in an electrical and mechanical favorable state.

  The assembly structure of a plurality of rectangular power storage devices that solves the above problem is that the electrode terminal protruding from the main body of the rectangular power storage device is connected by a bus bar and protrudes from the main body of another rectangular power storage device The electrode terminal has a groove opening on the contact surface with the bus bar, and the bus bar is formed on the contact surface with the electrode terminal and is inserted into the groove The gist is that the projection has irregularities on the surface of the portion that contacts the inner surface of the groove.

  According to this, the electrode terminal has a groove opening on the contact surface with the bus bar, and the protrusion of the bus bar having irregularities on the surface in contact with the inner surface of the groove is inserted into the groove of the electrode terminal. Therefore, the contact area between the bus bar and the electrode terminal can be increased to reduce the connection resistance and mechanically firmly connect. As a result, the bus bar and the electrode terminal can be connected in an electrically and mechanically good state.

In the assembly structure of the plurality of prismatic power storage devices, the unevenness may be wedge-shaped.
According to this, it is possible to prevent the protrusion of the bus bar from coming out of the groove of the electrode terminal.
In the assembly structure of the plurality of prismatic power storage devices, the protrusion may have a rectangular cross-sectional shape, and a longitudinal direction thereof may be an extending direction of the bus bar.

  According to this, it becomes easy to align the bus bar.

  According to the present invention, the bus bar and the electrode terminal can be connected in an electrically and mechanically good state.

(A) is a top view which shows typically the assembled battery of embodiment, (b) is a schematic right view of an assembled battery, (c) is a schematic front view of an assembled battery. (A) is a top view which shows an electrode terminal part typically, (b) is a schematic cross section in the AA of (a). The exploded sectional view showing typically an electrode terminal portion. The disassembled perspective view which shows an electrode terminal part typically. (A) is a top view which shows a bus bar typically, (b) is a front view which shows a bus bar typically (A arrow directional view of (a)). (A) is a top view which shows an electrode terminal typically, (b) is a front view which shows an electrode terminal typically (A arrow directional view of (a)).

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
In the drawings, the horizontal plane is defined by the orthogonal X and Y directions, and the vertical direction is defined by the Z direction.

  As shown in FIG. 1, the assembled battery 10 includes a battery module 20 configured by arranging a plurality of secondary batteries C1 to C9, a flat bus bar 30 that electrically connects the secondary batteries, and a bolt. 40, 41. Each of the secondary batteries C1 to C9 is a lithium ion secondary battery. Moreover, each secondary battery C1-C9 is a square-type secondary battery, and the main-body part 21 of the secondary batteries C1-C9 has comprised the thin square box type. The main body 21 is configured by winding a plate-like positive electrode and a plate-like negative electrode with a separator inside a battery case (can). The main body portions 21 of the secondary batteries C1 to C9 are arranged side by side in the Y direction, and the main body portions 21 of the adjacent secondary batteries are fixed with their side surfaces in contact with each other.

  In each of the secondary batteries C <b> 1 to C <b> 9, a positive electrode terminal 22 and a negative electrode terminal 23 protrude upward from the upper surface of the main body 21. In FIG. 1, the secondary battery C <b> 1 has a positive electrode terminal 22 disposed on the left side and a negative electrode terminal 23 disposed on the right side of the main body 21. In the secondary battery C2, a negative electrode terminal 23 is arranged on the left side of the main body 21, and a positive electrode terminal 22 is arranged on the right side. Hereinafter, the secondary battery C3 has a positive electrode terminal 22 on the left side of the main body 21, the negative electrode terminal 23 on the right, and the secondary battery C4 has a negative electrode terminal 23 on the left of the main body 21. The positive electrode terminal 22 is disposed on the left side of the main body 21 of the secondary battery C5, and the negative electrode terminal 23 is disposed on the right side of the main body 21. The secondary battery C6 has a negative electrode terminal 23 on the left side of the main body 21 and a positive electrode terminal 22 on the right, and the secondary battery C7 has a positive electrode terminal 22 on the right and a negative electrode terminal 22 on the right. The electrode terminal 23 is arranged. The secondary battery C8 has a negative electrode terminal 23 on the left side of the main body 21 and a positive electrode terminal 22 on the right, and the secondary battery C9 has a positive electrode terminal 22 on the right and a negative electrode terminal 22 on the right. The electrode terminal 23 is arranged.

The secondary batteries C <b> 1 to C <b> 9 are arranged in a state where a pedestal (nut) 24 penetrates the electrode terminals 22 and 23 on the upper surface of the main body 21.
The bus bar 30 extends in the Y direction. The bus bar 30 is fastened to the electrode terminals 22 and 23 of the adjacent secondary batteries. That is, on one end side of the bus bar 30, the bolt 40 penetrates the bus bar 30 from the upper side of the bus bar 30 and is screwed into the electrode terminal 22, and the bus bar 30 is fastened to the electrode terminal 22 of the secondary battery. On the other end side of the bus bar 30, a bolt 41 penetrates the bus bar 30 from the upper side of the bus bar 30 and is screwed into the electrode terminal 23, and the bus bar 30 is fastened to the electrode terminal 23 of the secondary battery by the bolt 41.

  In this way, the electrode terminals protruding from the main body of the prismatic secondary battery (for example, the secondary battery C1) as the prismatic power storage device are connected by the bus bar 30 and are used as other prismatic power storage devices. It is connected to an electrode terminal protruding from the main body of a secondary battery (for example, secondary battery C2). Thereby, the secondary batteries C1 to C9 are connected in series.

The structure of the connection portion between the bus bar 30 and the electrode terminals 22 and 23 will be described in detail with reference to FIGS.
As shown in FIG. 5, the bus bar 30 is made of a copper strip in which the main body 31 extends linearly, and circular through holes 32 are formed at both ends in the Y direction which is the long side direction. In FIG. 5 and the like, only one end portion of the bus bar 30 is illustrated for convenience, but the other end portion has the same configuration. Bolts 40 and 41 pass through the through hole 32. In this way, both ends of the bus bar 30 are connected to the electrode terminals 22 and 23.

As shown in FIG. 2, in the secondary batteries C <b> 1 to C <b> 9, a through hole 51 is formed in the top plate 50 of the main body portion 21.
The electrode terminals 22 and 23 made of copper or aluminum have the same configuration. As shown in FIG. 6, the main body portion 60 of the electrode terminals 22 and 23 has a columnar shape standing upright, and has a flange portion 61 at the lower end. As shown in FIG. 2, the main body portion 60 of the electrode terminals 22 and 23 protrudes upward from the top plate 50 through the through hole 51 of the top plate 50 from the inside of the main body portion 21 of the secondary batteries C1 to C9. An insulating resin collar 52 and a sealing material 53 are disposed between the outer peripheral surface of the main body 60 of the electrode terminals 22 and 23 and the through hole 51 of the top plate 50, and the electrode terminals 22, 23 and the top plate 50 are insulated. The outer peripheral surface of the main body 60 of the electrode terminals 22 and 23 is formed with a male screw, and a base (nut) 24 is screwed into a portion of the main body 60 of the electrode terminals 22 and 23 that protrudes upward from the top plate 50. . The electrode terminals 22 and 23 are fastened and fixed to the top plate 50 by the pedestal (nut) 24. The upper portions of the body portions 60 of the electrode terminals 22 and 23 protrude upward from the pedestal (nut) 24. A bus bar 30 is disposed on the upper surface of the main body 60 of the electrode terminals 22 and 23.

  As shown in FIG. 3, the upper surface of the main body portion 60 of the electrode terminals 22 and 23 is a contact surface 60a with the bus bar 30, and a female screw hole 62 opened to the upper surface (contact surface 60a) is formed at the center of the contact surface 60a. The female screw hole 62 is formed to extend downward. As shown in FIGS. 2 and 3, screw portions 43 of bolts 40 and 41 that penetrate the bus bar 30 are screwed into the female screw holes 62.

  As shown in FIG. 6, grooves 63 and 64 are formed on the upper surface of the main body portion 60 of the electrode terminals 22 and 23, that is, on the contact surface 60 a with the bus bar 30. As shown in FIG. 6B, each of the grooves 63 and 64 has an opening on the upper surface of the main body portion 60 of the electrode terminals 22 and 23 and has a predetermined depth, and a pair of parallel inner side surface 66a and bottom surface 66b. have. As shown in FIG. 6A, each of the grooves 63 and 64 extends linearly in the Y direction. Both grooves 63 and 64 are formed with the female screw hole 62 sandwiched in the Y direction passing through the center of the female screw hole 62.

  As shown in FIGS. 3 and 5, the lower surface of the main body 31 of the bus bar 30 is a contact surface 31a with the electrode terminals 22 and 23, and the protrusion 33 corresponding to the grooves 63 and 64 of the electrode terminal is formed on the contact surface 31a. , 34 are formed. Each of the protrusions 33 and 34 has a rectangular cross-sectional shape, and the longitudinal direction thereof is the extending direction of the bus bar 30. That is, as shown in FIG. 5A, each protrusion 33, 34 sandwiches the through hole 32 in the Y direction that passes through the center of the through hole 32 linearly in the Y direction that is the extending direction of the bus bar 30. It is formed with. The protrusion 33 is inserted into the groove 63 and the protrusion 34 is inserted into the groove 64.

  As shown in FIG. 5B, the protrusion 33 extends downward, and has projections and depressions 35 on the surface in the X direction, that is, on the surface in contact with the inner surface 66 a of the groove 63. . Similarly, the protrusion 34 extends downward, and has an unevenness 35 on the surface in the X direction, that is, the surface of the portion that contacts the inner side surface 66 a of the groove 64. Each unevenness 35 has a wedge shape. That is, the horizontal surface 35a that protrudes in the horizontal direction and the inclined surface 35b that extends obliquely downward from the tip of the horizontal surface 35a are repeated. In FIG. 5 etc., it has a three-stage structure having three horizontal surfaces 35a and three inclined surfaces 35b.

  The protrusions 33 and 34 on the bus bar 30 are, for example, processed (formed) in advance as separate bodies and attached (integrated) to the main body 31. Thereby, the bus bar 30 having the protrusions 33 and 34 can be manufactured.

  As shown in FIGS. 2, 3, and 4, the protrusion 33 of the bus bar 30 is press-fitted into the groove 63 of the main body 60 of the electrode terminals 22 and 23 and the bus bar 30 is inserted into the groove 64 of the main body 60 of the electrode terminals 22 and 23. The protrusion 34 is press-fitted. Thereby, the inner surface 66a in the groove 63 of the main body 60 of the electrode terminals 22 and 23 and the unevenness 35 of the protrusion 33 of the bus bar 30 are in close contact with each other. Similarly, the inner surface 66a of the groove 64 of the main body 60 of the electrode terminals 22 and 23 and the unevenness 35 of the protrusion 34 of the bus bar 30 are in close contact.

  Further, as shown in FIG. 2A, the protrusions 33 and 34 extend in the Y direction in which current flows, that is, the direction connecting the electrode terminals 22 and 23. Further, the grooves 63 and 64 of the electrode terminals 22 and 23 are positioned so as to correspond to the protrusions 33 and 34, and the direction is determined when the bus bar 30 is placed on the electrode terminals 22 and 23.

Next, a connection method between the secondary batteries, that is, an assembly process of the bus bar 30 to the electrode terminals 22 and 23 of the secondary battery will be described.
As shown in FIG. 3, the electrode terminals 22, 23 and the top plate 50 are insulated from each other by the insulating resin collar 52 and the sealing material 53, and project upward from the top plate 50 in the main body 60 of the electrode terminals 22, 23. A base (nut) 24 is screwed into the part, and the electrode terminals 22 and 23 are fastened to the top plate 50 by the base (nut) 24.

  Then, the bus bar 30 is disposed on the upper surface of the main body 60 of the electrode terminals 22 and 23. At this time, the protrusion 33 of the bus bar 30 is press-fitted into the groove 63 of the main body 60 of the electrode terminals 22 and 23 and the protrusion 34 of the bus bar 30 is press-fitted into the groove 64 of the main body 60 of the electrode terminals 22 and 23.

Subsequently, the screw portions 43 of the bolts 40 and 41 are screwed into the female screw holes 62 of the main body portions 60 of the electrode terminals 22 and 23 through the through holes 32 of the bus bar 30.
Here, when the bus bar 30 is placed on the electrode terminals 22 and 23 and fastened with the bolts 40 and 41, the protrusions 33 and 34 are in the direction in which the bus bar 30 extends as shown in FIG. Grooves 63 and 64 are provided in the electrode terminals 22 and 23 so as to extend in the direction and correspond to the protrusions 33 and 34. Thus, the orientation of the bus bar 30 is determined when the bus bar 30 is placed on the electrode terminals 22 and 23, and the assembly is easy. Thereafter, the bus bar 30 is aligned with the position of the through hole 32 of the bus bar 30 and the position of the female screw hole 62 of the electrode terminals 22 and 23. Is moved in the Y direction.

  Further, the electrode terminals 22 and 23 are plastically deformed so that the projections 33 of the bus bar 30 are press-fitted into the grooves 63 of the main body portion 60 of the electrode terminals 22 and 23 and the bus bars 30 are inserted into the grooves 64 of the main body portion 60 of the electrode terminals 22 and 23. The projection 34 is press-fitted. Therefore, the inner side surface 66a of the groove 63 of the main body portion 60 of the electrode terminals 22 and 23 and the unevenness 35 of the protrusion 33 of the bus bar 30 are in close contact, and the inner side surface 66a of the groove 64 of the main body portion 60 of the electrode terminals 22 and 23 and the bus bar. The projections and recesses 30 of the projections 30 are in close contact with each other, and the contact area increases and is difficult to come off.

Next, the operation will be described.
The electrode terminals 22 and 23 are provided with grooves 63 and 64, and the bus bar 30 is provided with projections 33 and 34 corresponding thereto. At that time, the protrusions 33 and 34 are not easily removed (not easily loosened) after being inserted into the surface of the projections 33 and 34 by making the protrusions 35 and 34 into a wedge shape. Further, contact is made at two places between the lower surface of the bus bar 30 and the upper surfaces of the electrode terminals 22 and 23 and between the protrusions 33 and 34 of the bus bar 30 and the inner side surfaces 66a of the grooves 63 and 64 of the electrode terminals 22 and 23. doing. Therefore, the contact area between the lower surface of the bus bar 30 and the upper surfaces of the electrode terminals 22 and 23 and the contact between the protrusions 33 and 34 of the bus bar 30 and the inner surfaces 66a of the grooves 63 and 64 of the electrode terminals 22 and 23 are further increased. The area can be added and the contact area can be increased. As the contact area increases, the electrical resistance can be reduced.

  In addition, the protrusions 33 and 34 are aligned in a straight line, and each protrusion 33 and 34 extends in the extending direction of the bus bar 30 (the direction connecting the positive and negative electrode terminals). On the other hand, grooves 63 and 64 are formed in the electrode terminals 22 and 23 so as to correspond to the protrusions 33 and 34. Therefore, the protrusions 33 and 34 can be fitted into the grooves 63 and 64 only by placing the bus bar 30 straight, and the bolts 40 and 41 can be inserted thereafter, so that the assembly is easy. In other words, the direction is determined when the bus bar 30 is placed on the electrode terminals 22 and 23, and the extension direction of the bus bar 30 may be adjusted to the female screw hole 62, so that the dimensional tolerance can be relaxed and the manufacture is facilitated.

The structure of the connection portion between the bus bar 30 and the electrode terminals 22 and 23 is compared with Patent Document 1.
In Patent Document 1, the bus bar is bolted to the electrode terminal, and the cylindrical connecting portion of the bus bar is pressed against the tapered surface of the electrode terminal to deform the cylindrical connecting portion so that an inward stress is always applied. Yes. Therefore, when the bolt that tightens the bus bar is tightened, if the bolt is loosened, the taper surface (inclined surface) of the electrode terminal causes a force in the direction in which the cylindrical connection portion of the bus bar is detached from the taper surface of the electrode terminal. In addition, contact resistance tends to increase.

  On the other hand, in the present embodiment, since the irregularities 35 on the surfaces of the protrusions 33 and 34 of the bus bar 30 are inserted into the grooves 63 and 64 of the electrode terminals 22 and 23, the bus bar 30 is tightened even if the bolts 40 and 41 for fastening the bus bar are loosened. As long as the unevenness 35 on the surface of the projections 33 and 34 does not move, the contact resistance does not change. Therefore, it is difficult to pull out the bus bar by mechanically giving resistance while increasing the contact area electrically. Thus, by reducing the contact resistance R, a large current can be passed to the load connected to the assembled battery. That is, since V = RI, by decreasing the R value, the V value is constant, so that the I value can be increased, and the output can be increased because the output depends on the current.

As described above, according to the embodiment, the following effects can be obtained.
(1) As an assembled structure of the secondary batteries C1 to C9 as a plurality of rectangular power storage devices, the electrode terminals 22 and 23 have grooves 63 and 64 that open to the contact surface 60a with the bus bar 30. On the other hand, the bus bar 30 has protrusions 33 and 34 that are formed on the contact surface 31 a with the electrode terminals 22 and 23 and are inserted into the grooves 63 and 64, and the protrusions 33 and 34 are on the inner surface 66 a of the grooves 63 and 64. Concavities and convexities 35 are provided on the surface of the contacting portion. Therefore, the contact area between the bus bar 30 and the electrode terminals 22 and 23 can be increased to reduce the connection resistance and mechanically firmly connect. As a result, the bus bar 30 and the electrode terminals 22 and 23 can be electrically and mechanically connected in a good state.

  (2) Since the irregularities 35 have a wedge shape, the projections 33 and 34 can be inserted into the grooves 63 and 64 and are not easily removed. Therefore, the protrusions 33 and 34 of the bus bar 30 can be made difficult to come off from the grooves 63 and 64 of the electrode terminals 22 and 23.

(3) Since the protrusions 33 and 34 have a rectangular cross-sectional shape and the longitudinal direction thereof is the extending direction of the bus bar 30, the bus bar 30 can be easily aligned.
The embodiment is not limited to the above, and may be embodied as follows, for example.

  The irregularities 35 on the surfaces of the protrusions 33 and 34 are wedge-shaped, but instead, the surfaces of the protrusions 33 and 34 may be formed into rough surfaces. That is, the surface of the protrusion may be surface-treated to make the surface roughness of the protrusion larger than the upper surface of the electrode terminal (the surface of the protrusion is rough). Also in this case, the rough surface makes it difficult to slip mechanically. More specifically, the surface of the protrusion is roughened by shot blasting or the like in a state where the dimensional tolerances of the protrusion are matched so that the protrusion and the groove are inserted exactly. Thereby, it becomes difficult to slip due to unevenness on the surface.

・ Two protrusions are provided, but this is not a limitation. There may be one protrusion or three or more protrusions.
Although the bus bar is screw-fastened to the electrode terminal, the present invention is not limited to this, and may be fastened with a rivet, for example.

  DESCRIPTION OF SYMBOLS 21 ... Main-body part, 22, 23 ... Electrode terminal, 30 ... Bus bar, 31a ... Contact surface, 33, 34 ... Projection, 35 ... Unevenness, 60a ... Contact surface, 63, 64 ... Groove, 66a ... Inner side surface, C1-C9 ... secondary battery.

Claims (3)

An electrode terminal protruding from the main body portion of the rectangular power storage device is an assembly structure of a plurality of square power storage devices connected by a bus bar and connected to the electrode terminal protruding from the main body portion of another square power storage device. ,
The electrode terminal has a groove that opens in a contact surface with the bus bar,
The bus bar has a protrusion formed on a contact surface with the electrode terminal and inserted into the groove,
An assembly structure of a plurality of prismatic power storage devices, wherein the protrusion has irregularities on the surface of the portion that contacts the inner surface of the groove.   The assembled structure of a plurality of rectangular power storage devices according to claim 1, wherein the unevenness has a wedge shape.   The assembly structure of a plurality of prismatic power storage devices according to claim 1, wherein the protrusion has a rectangular cross-sectional shape, and a longitudinal direction thereof is an extending direction of the bus bar.