JP2013105674A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the electrical resistance of a secondary battery and a bus bar while enhancing the workability of bus bar attachment work.SOLUTION: A bus bar 50 connecting the terminals 61, 71 of the external positive electrode and the negative electrode of a secondary battery 1 has a substantially flat and planar base 51, and a plurality of heat radiation fins 52 standing substantially perpendicularly to the base 51. An attachment part 51a having a pair of through holes 53 is formed in the base 51, and the heat radiation fin 52 is not formed in the attachment part 51a. The terminals 61, 71 of the external positive electrode and the negative electrode having a bolt structure penetrate the through holes 53, and the bus bar 50 is fastened to a battery cover 3 by means of nuts 57.

Description

  The present invention relates to an assembled battery in which positive and negative terminals of each secondary battery are connected by a bus bar.

An assembled battery is known in which a plurality of prismatic secondary batteries such as lithium ion secondary batteries are connected to each other by a bus bar. In recent years, such an assembled battery has attracted attention as a power supply device for electric vehicles and hybrid electric vehicles.
The assembled battery charges and discharges a large current and generates a large amount of heat, and the temperature rises to a high temperature. For this reason, it is necessary to cool.

  A method using a heat sink is known as a cooling means. A structure is known in which heat dissipation fins are provided on bus bars that electrically connect secondary batteries to each other in order to reduce costs and improve assembly efficiency (for example, Patent Document 1, FIGS. 1-3, 27th). See paragraph). The assembled battery described in this document uses a bus bar in which a metal plate is bent and three peaks and two valleys are alternately formed. This bus bar is placed between the positive and negative terminals of adjacent secondary batteries formed in a plate shape. This document does not describe the mounting structure between the bus bar and the positive and negative terminals.

Japanese Patent Laid-Open No. 2005-100840

  In the assembled battery described in the above-mentioned patent document, the entire bus bar is composed of plate-shaped heat radiation fins. The plate-shaped heat radiation fin has a small plate thickness and a small contact area with the positive and negative electrode terminals. Therefore, the electrical resistance between the bus bar and the secondary battery is increased. Moreover, although there is no mention regarding the attachment structure of a bus bar, since the attachment part for fixation is not formed in the bus bar, attachment work is difficult.

  In the assembled battery of the present invention, a power generation element including a positive electrode and a negative electrode is accommodated in a battery container constituted by a battery lid and a battery can, and a positive electrode terminal and a negative electrode connected to the positive electrode and the negative electrode, respectively. A plurality of secondary batteries provided with terminals protruding from the inside of the battery lid, and a bus bar connecting the positive terminal and the negative terminal of each secondary battery, the bus bar being disposed substantially parallel to the upper surface of the battery lid And a plurality of heat dissipating fins provided substantially perpendicular to the mounting portion.

  According to the assembled battery of the present invention, the bus bar has the attachment portion and the heat radiation fin provided substantially perpendicular to the attachment portion, and the contact portion increases the contact area between the positive electrode and the negative electrode terminal. be able to. For this reason, the electrical resistance between a bus bar and a secondary battery can be reduced. In addition, since the attachment portion is disposed substantially parallel to the upper surface of the battery lid, the bus bar can be attached while visually recognizing the attachment portion from above the battery lid, so that the efficiency of the attachment operation is improved.

The external appearance perspective view as one Embodiment of the secondary battery used for the assembled battery which concerns on this invention. FIG. 2 is an exploded perspective view of the secondary battery shown in FIG. 1. The expanded sectional view cut | disconnected along the III-III line of FIG. The perspective view of the state which showed one Embodiment of the electric power generation element incorporated in a secondary battery, and expand | deployed one part. The external appearance perspective view of one Embodiment of the assembled battery by this invention. (A) is a top view of the assembled battery illustrated in FIG. 5, (b) is a front view of the assembled battery illustrated in FIG. FIG. 6 is an enlarged perspective view of the bus bar illustrated in FIG. 5. (A) is a top view of the bus bar illustrated in FIG. 7, (b) is a side view of the bus bar illustrated in FIG. The external appearance perspective view of Embodiment 2 of the assembled battery by this invention. (A) is a top view of the assembled battery shown in FIG. 9, (b) is a front view of the assembled battery shown in FIG. The external appearance perspective view of the bus-bar as Embodiment 3 used for the assembled battery of this invention. The external appearance perspective view of the bus bar as Embodiment 4 used for the assembled battery of this invention. The external appearance perspective view of the bus-bar as Embodiment 5 used for the assembled battery of this invention. The external appearance perspective view as other embodiment of the secondary battery used for the assembled battery of this invention. The expansion perspective view of the bus-bar as Embodiment 6 used for the assembled battery comprised using the secondary battery illustrated in FIG. (A) is a top view of the bus bar illustrated in FIG. 15, (b) is a side view of the bus bar illustrated in FIG.

-Embodiment 1-
Hereinafter, an embodiment of an assembled battery according to the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view showing an embodiment of a lithium ion prismatic secondary battery as a unit battery constituting the assembled battery of the present invention, and FIG. 2 is an exploded view of the secondary battery shown in FIG. It is a perspective view.
The secondary battery 1 includes a power generation element 40 housed in a thin, substantially rectangular parallelepiped battery container composed of a battery lid 3 and a battery can 4, and is configured by injecting a nonaqueous electrolyte solution (not shown). ing. The battery lid 3 and the battery can 4 are made of aluminum, for example.

  A positive electrode current collector plate 21, a negative electrode current collector plate 31, and the like are integrally assembled to the battery lid 3 to constitute a battery lid unit 10. The positive electrode current collector plate 21 and the negative electrode current collector plate 31 of the battery lid unit 10 are respectively applied to, for example, ultrasonic waves on the positive electrode metal foil 41a (see FIG. 4) or the negative electrode current collector foil 42a (see FIG. 4) of the power generation element 40. It is joined by welding and integrated as a battery lid / power generation unit.

  The battery can 4 is formed in a thin box shape having an opening 4a on the battery lid 3 side. The power generation element 40 is housed in the battery can 4 in a state of being a battery lid / power generation unit. The power generation element 40 may be stored in the battery can 4 after being stored in an insulating sheet (not shown).

FIG. 4 is an external perspective view in a state where the winding end side of the power generation element 40 is developed.
The power generation element 40 is formed by winding a positive electrode 41 and a negative electrode 42 in a flat shape around a shaft core (not shown) with first and second separators 43 and 44 interposed therebetween.
The positive electrode 41 has a positive electrode mixture layer 41b formed on both front and back surfaces of a positive electrode metal foil 41a made of, for example, aluminum foil. The positive electrode mixture layer 41b is formed by coating the positive electrode metal foil 41a with the positive electrode mixture so that a positive electrode mixture untreated portion 41c where the positive electrode metal foil 41a is exposed is formed on one side edge of the positive electrode metal foil 41a. Formed.
The negative electrode 42 is obtained by, for example, coating a negative electrode mixture layer 42b on both front and back surfaces of a negative electrode metal foil 42a made of copper foil or the like. In the negative electrode mixture layer 42b, a negative electrode mixture untreated portion 42c in which the negative electrode metal foil 42a is exposed is formed on the other side edge that is a side edge opposite to the side edge where the positive electrode mixture untreated portion 41c is disposed. Thus, the negative electrode metal foil 42a is formed by applying a negative electrode mixture.

The positive electrode mixture layer 41b is composed of 10 parts by weight of PVDF as a conductive material and 10 parts by weight of PVDF with respect to 100 parts by weight of lithium manganate (chemical formula LiMn ₂ O ₄ ) as a positive electrode active material. And NMP as a dispersion solvent is added and kneaded. This positive electrode mixture is applied to both surfaces of an aluminum foil having a thickness of 20 μm, leaving the positive electrode mixture untreated portions 41c. Thereafter, drying, pressing, and cutting are performed to obtain a positive electrode 41 having a thickness of 90 μm (total of both front and back surfaces) of the positive electrode active material application portion not including the aluminum foil.

  In the negative electrode mixture layer 42b, 10 parts by weight of polyvinylidene fluoride (hereinafter referred to as PVDF) is added as a binder to 100 parts by weight of amorphous carbon powder as a negative electrode active material, and a dispersion solvent is added thereto. N-methyl pyrrolidone (hereinafter referred to as NMP) is added and kneaded. This negative electrode mixture is applied to both sides of a 10 μm thick copper foil leaving the negative electrode mixture untreated portions 42c. Thereafter, drying, pressing, and cutting are performed to obtain a negative electrode 42 having a thickness of 70 μm (total on both front and back surfaces) of the negative electrode active material coating portion not including the copper foil.

  In order to form the power generation element 40, the winding start side end of the negative electrode 42 is respectively connected to the positive electrode 41 between the first and second separators 43 and 44, the tip of which is welded to a shaft core (not shown). It is arranged and wound so as to be located inside the winding start side end. In this case, the positive electrode mixture untreated portion 41c and the negative electrode mixture untreated portion 42c are arranged so as to be located on the side edges on the opposite side in the width direction (direction orthogonal to the winding direction). The width of the negative electrode mixture layer 42b is formed wider than the width of the positive electrode mixture layer 41b. Moreover, the width | variety of the 1st separator 43 is set as the dimension which exposes the positive mix untreated part 41c of the positive electrode 41 to the exterior in the one side edge side. The width of the second separator 44 is such that the negative electrode mixture untreated portion 42c of the negative electrode 42 is exposed to the outside on the other side edge side.

  Thus, the power generation element 40 is formed in a state where the positive electrode mixture untreated portion 41c of the positive electrode metal foil 41a is exposed to the outside and the negative electrode mixture untreated portion 42c of the negative electrode metal foil 42a is exposed to the outside. ing.

  The battery lid 3 is provided with a non-aqueous electrolyte injection port, and this injection port is sealed by an injection plug 15 after the electrolyte solution is injected. The liquid injection stopper 15 is joined to the peripheral edge of the liquid injection opening of the battery lid 3 by, for example, laser welding. In addition, a safety valve 16 is formed substantially at the center in the longitudinal direction of the battery lid 3. The safety valve 16 is for releasing the gas generated inside the battery due to overcharge or the like to the outside of the battery cell. The safety valve 16 is formed such that a groove is formed by locally thinning the battery lid 3, and the groove portion is easily cleaved.

In the non-aqueous electrolyte, lithium hexafluorophosphate (LiPF ₆ ) is dissolved at a concentration of 1 mol / liter in a mixed solution in which ethylene carbonate and dimethyl carbonate are mixed at a volume ratio of 1: 2. Can be used.

  In the above, although PVDF was illustrated as a binder, polytetrafluoroethylene (PTFE), polyethylene, polystyrene, polybutadiene, butyl rubber, nitrile rubber, styrene / butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, various latexes, acrylonitrile Polymers such as vinyl fluoride, vinylidene fluoride, propylene fluoride, and chloroprene fluoride, and mixtures thereof may be used.

In addition to the above, as the non-aqueous electrolyte, a non-aqueous electrolyte obtained by using a general lithium salt as an electrolyte and dissolving it in an organic solvent may be used. The solvent is not particularly limited. For example, as the electrolyte, LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, or a mixture thereof can be used. Examples of the organic solvent include propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, Diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propiontonyl, etc., or a mixed solvent of two or more of these may be used, and the mixing ratio is not limited.

FIG. 3 is an enlarged cross-sectional view taken along line III-III in FIG.
The peripheral portion 3a of the battery lid 3 is thin (see FIG. 4), and the peripheral portion 3a is joined to the peripheral portion of the opening 4a of the battery can 4 and, for example, joined to the battery can 4 by laser welding. A battery container having a sealed structure is formed with respect to the outside.
On the positive electrode side, a terminal structure in which an external positive electrode terminal (positive electrode terminal) 61, a positive electrode connection terminal 62, a positive electrode terminal plate 63, an insulating plate 64, a gasket 65, and a positive electrode current collector plate 21 are mounted on the battery lid 3 is configured. ing.
The external positive electrode terminal 61, the positive electrode connection terminal 62, the positive electrode terminal plate 63, and the positive electrode current collector plate 21 are formed of a conductive member such as aluminum.

  Openings 63 a and 63 b are formed in the positive terminal plate 63. The external positive terminal 61 has a bolt structure having a terminal portion 61a and a base portion 61b, and a male screw (male screw portion) is formed on the outer periphery of the terminal portion 61a. The terminal portion 61 a of the external positive terminal 61 is inserted through the opening 63 a of the positive terminal plate 63. The base portion 61 b of the external positive terminal 61 is accommodated in the step portion 64 a of the insulating plate 64, and is sandwiched between the positive terminal plate 63 and the step portion 3 b of the battery cover 3 via the step portion 64 a of the insulating plate 64. ing.

  The gasket 65 is formed in a stepped ring shape having an opening 65a. The gasket 65 is inserted through the opening 3c of the battery lid. The positive electrode connection terminal 62 is formed in a stepped columnar shape having a large-diameter lower cylindrical portion 62a and a small-diameter upper cylindrical portion 62b. In the positive electrode connection terminal 62, the upper cylindrical portion 62 b is inserted into the opening 65 a of the gasket 65 and the opening 63 b of the positive electrode terminal plate 63. The positive electrode terminal plate 63 is caulked by the upper cylindrical portion 62 b of the positive electrode connection terminal 62, and is fixed to the battery lid 3 together with the positive electrode terminal plate 63.

The positive terminal structure is formed as follows.
First, the opening 64 b of the insulating plate 64 is aligned with the opening 3 c of the battery lid 3, and the step 64 a of the insulating plate 64 is accommodated in the step 3 b of the battery lid 3. Next, the base portion 61 b of the external positive electrode terminal 61 is accommodated in the step portion 64 a of the insulating plate 64. Next, the opening 63 a of the positive terminal plate 63 is fitted into the terminal 61 a of the external positive terminal 61, and the opening 63 b is aligned with the opening 3 c of the battery lid 3. Next, the gasket 65 is inserted through the opening 3 c of the battery lid 3 and the opening 64 b of the insulating plate 64. In this step, the gasket 65 may first be inserted into the opening 3c of the battery lid 3, and then the insulating plate 64 may be assembled.

On the other hand, the positive electrode current collector plate 21 is connected in advance to the positive electrode current collector plate 21 by fitting the opening 21c thereof to the lower cylinder portion 62a of the positive electrode connection terminal 62 and crimping the end surface of the lower cylinder portion 62a. The terminal 62 is fixed by caulking.
Then, the upper cylindrical portion 62b of the positive electrode connecting terminal 62 is inserted into the opening 65a of the gasket 65 and the opening 63b of the positive electrode terminal plate 63, and the upper cylindrical portion 62b is pressure-bonded so that the positive electrode terminal plate 63 and the positive electrode connecting terminal 62 are Is fixed to the battery lid 3 by caulking.

In the above description, the positive electrode current collector 21 and the positive electrode connection terminal 62 are fixed in advance by caulking. However, the positive electrode terminal plate 63 and the positive electrode current collector plate 21 are simultaneously crimped to the positive electrode connection terminal 62 in a state where the positive electrode connection terminal 62 is inserted into the opening 65 a of the gasket 65 and the opening 63 b of the positive electrode terminal plate 63. You may do it.
Thereby, the positive electrode terminal plate 63, the external positive electrode terminal 61, the insulating plate 64, the gasket 65, the positive electrode connection terminal 62, and the positive electrode current collector plate 21 are fixed to the battery cover 3 and integrated.

On the negative electrode side, a terminal having an external negative electrode terminal (negative electrode terminal) 71, a negative electrode connection terminal 72, a negative electrode terminal plate 73, an insulating plate 64, a gasket (not shown) and a negative electrode current collector plate 31 attached to the battery lid 3. The structure is structured.
The external negative electrode terminal 71, the negative electrode connection terminal 72, the negative electrode terminal plate 73, and the negative electrode current collector plate 31 are formed of a conductive member such as copper. Similarly to the external positive terminal 61, the external negative terminal 71 has a bolt structure having a terminal part and a base part, and a male screw (male thread part) is formed on the outer periphery of the terminal part. The negative electrode current collecting plate 31 is the same as the positive electrode current collecting plate 21 except that the material is different and the shape is bilaterally symmetric. The external negative electrode terminal 71, the negative electrode connection terminal 72, and the negative electrode terminal plate 73 are the same as the corresponding positive-side members, except that the materials are different. Moreover, the negative electrode side insulating plate 64 and the gasket are the same members as the positive electrode side.

  The terminal structure on the negative electrode side is the same as the terminal structure on the positive electrode side except for the above, and the assembly method is also the same.

5 is an external perspective view showing an embodiment of the assembled battery according to the present invention, FIG. 6 (a) is a plan view of the assembled battery shown in FIG. 5, and FIG. 6 (b) is FIG. 2 is a front view of the assembled battery illustrated in FIG.
The assembled battery 100 is configured by arranging a plurality of the secondary batteries 1 described above as one embodiment in close contact with each other in the thickness direction. The secondary batteries 1 are arranged alternately opposite to each other so that the external positive electrode terminal 61 and the external negative electrode terminal 71 face each other.

  The external positive electrode terminal 61 and the external negative electrode terminal 71 of the adjacent secondary battery 1 are electrically connected by the bus bar 50, and the whole secondary battery 1 is connected in series. The external positive electrode terminal 61 of the secondary battery 1 disposed on one end side of the plurality of secondary batteries 1 and the external negative terminal 71 of the secondary battery 1 disposed on the other end side are connected to an external device by a connection member (not shown). Then, a discharge current is supplied from the assembled battery 100.

7 is an enlarged perspective view of the bus bar shown in FIG. 5, FIG. 8 (a) is a plan view of the bus bar shown in FIG. 7, and FIG. 8 (b) is a bus bar shown in FIG. FIG.
The bus bar 50 is integrally formed with a rectangular flat plate-like base portion 51 and a plurality of heat-dissipating fins 52 erected perpendicularly to the base portion 51. The bus bar 50 is made of copper, for example, by a casting method.

The base portion 51 is formed with a pair of circular through holes 53 into which the terminal portion 61a of the external positive terminal 61 or the terminal portion 72a of the external negative terminal 71 is inserted. A region of the base portion 51 where the pair of through holes 53 are formed is a mounting portion 51a over a predetermined width, and the heat radiation fin 52 is not formed in the region of the mounting portion 51a. That is, at least a heat radiation fin 52 is not formed on a straight region connecting the outer diameters (outer peripheral edges) of the circles of the pair of through holes 53.
Each of the plurality of heat radiation fins 52 has a plate shape extending in parallel with a straight line connecting the centers of the pair of through holes 53, and is formed to have the same length as the length of the base portion 51.

As shown in FIG. 6A, each bus bar 50 has an external positive electrode terminal of one secondary battery 1 adjacent to the through hole 53 of the base portion 51 with the heat radiation fin 52 positioned inside. 61 and the external negative terminal 71 of the other secondary battery 1 are inserted. And in this state, it fastens to the battery cover 3 of the secondary battery 1 with the nut 57 screwed together with the terminal part 61a of the external positive electrode terminal 61 and the terminal part 71a of the negative electrode external terminal 71.
The bus bar 50 is fixed to the battery lid 3 and has a size that does not overlap the safety valve 16. When the mist-like gas is ejected from the secondary battery 1, a discharge pipe (not shown) for leading the gas is attached to the safety valve 16. The bus bar 50 has a shape, size, and mounting position relationship that do not interfere with the mounting of the discharge pipe.

The bus bar 50 has a base portion 51 that is parallel to the upper surface 3a of the battery lid 3, and an attachment portion 51a that does not have the fins 52 standing up is provided on one side edge of the base portion 51 for heat dissipation. It has a structure. For this reason, the attaching part 51a can be visually recognized from the upper side of the battery cover 3, and the operation | work which fastens the bus-bar 50 to the battery cover 3 using the nut 57 can be performed easily. In addition, since the heat dissipating fins 52 are not erected on the mounting portion 51a, there is no obstacle to the fastener, and the fastening work by the nut 57 can be performed efficiently.
Further, the bus bar 50 has a flat base portion 51, and the entire lower surface is in contact with the upper surface 3a of the battery lid 3, so that the contact area is increased and the electrical resistance with the secondary battery 1 is reduced. be able to.

  As is clear with reference to FIG. 5, the heat dissipating fins 52 of each bus bar 50 extend in parallel with the arrangement direction of the secondary batteries 1. For this reason, by causing a cooling medium such as air to flow in parallel with the arrangement direction of the secondary batteries 1, the heat generated in the secondary batteries 1 is efficiently released from the heat radiation fins 52, and the secondary battery 1 is removed. Can be cooled.

  As shown in FIG. 6B, the heat dissipating fins 52 provided on the bus bar 50 are fixed to the battery lid 3, and the upper ends 52a thereof are external positive and external negative terminal 61, It is preferable that the terminal portions 61a and 71a of the 71 have substantially the same height as the upper end portions 61c and 71c, in other words, substantially the same plane. Thereby, the cooling effect by the fins 52 for heat dissipation can be made sufficient, and the physique of the assembled battery 100 can be prevented from becoming large.

Embodiment 2
9 is an external perspective view of Embodiment 2 of the assembled battery according to the present invention, FIG. 10 (a) is a plan view of the assembled battery illustrated in FIG. 9, and FIG. 10 (b) is FIG. 2 is a front view of the assembled battery illustrated in FIG.
The assembled battery 100A shown as Embodiment 2 is attached to the battery cover 3 of the secondary battery 1A with the bus bar 50A having the heat dissipating fins 52 arranged on the side surface side of the secondary battery 1A.
That is, in each secondary battery 1 </ b> A, the terminals 61 and 71 of the external positive electrode and the external negative electrode are attached to the battery lid 3 in the vicinity of the central portion and the safety valve 16. Each bus bar 50A is inserted through the pair of through holes 53 provided in the attachment portion 51 into the terminals 61 and 71 of the external positive electrode and the external negative electrode provided on the center side of the battery cover 3, and the nut 57 It is fixed by.

Accordingly, the heat dissipating fins 52 of each bus bar 50A are disposed on the side surface side of the secondary battery 1A.
Also in the second embodiment, the bus bar 50 </ b> A is attached so as not to overlap the safety valve 16.
Other configurations are the same as those of the first embodiment, and the corresponding members are denoted by the same reference numerals and description thereof is omitted.
The bus bar 50A in the second embodiment is the same as the bus bar 50 in the first embodiment, and can be shared by rotating the direction by 180 ° C.
The assembled battery 100A of the second embodiment also has the same effect as the assembled battery 100 of the first embodiment.

Embodiment 3
FIG. 11 is an external perspective view of a bus bar as a third embodiment used in the assembled battery of the present invention. The bus bar 50B of the third embodiment can be applied to the secondary batteries 1 and 1A constituting the assembled batteries 100 and 100A shown in the first and second embodiments.
In the bus bar 50 </ b> B, each heat radiation fin 52 a extends substantially perpendicular to a straight line connecting the centers of the pair of through holes 53.

As in the case of the first and second embodiments, the bus bar 50B is inserted into the pair of through holes 53 into the terminals 61 and 71 of the external positive electrode and the external negative electrode and fastened to the battery lid 3 by the nut 57. In this state, the heat dissipating fins 52a of the bus bars 50B are arranged in a direction perpendicular to the arrangement direction of the secondary batteries 1 and 1A.
Therefore, by causing a cooling medium such as air to flow in a direction perpendicular to the direction in which the secondary batteries 1 and 1A are arranged, the heat generated in the secondary batteries 1 and 1A is efficiently released from the heat radiation fins 52a. The secondary batteries 1 and 1A can be cooled.
The other structure of the bus bar 50B is the same as that of the bus bars 50 and 50A of the first and second embodiments, and the corresponding parts are denoted by the same reference numerals and description thereof is omitted.

-Embodiment 4-
FIG. 12 is an external perspective view of a bus bar as a fourth embodiment used in the assembled battery of the present invention. The bus bar 50C of the fourth embodiment can be applied to the secondary batteries 1 and 1A constituting the assembled batteries 100 and 100A shown in the first and second embodiments.
In the bus bar 50C, the heat radiation fins 52b are not formed in a plate shape but in a columnar shape, and are arranged in a matrix outside the region of the mounting portion 51a of the base portion 51.
In the assembled battery configured by connecting the secondary batteries 1 and 1A using such a bus bar 50C, a cooling medium such as air flows in a direction parallel to or perpendicular to the arrangement direction of the secondary batteries 1 and 1A. Even if it is a case, or it is a case where it flows in the diagonal direction with respect to the arrangement direction of the secondary batteries 1 and 1A, the heat generated in the secondary batteries 1 and 1A is efficiently transmitted from the heat radiation fins 52b. The secondary battery 1, 1 </ b> A can be cooled.
The other structure of the bus bar 50C is the same as that of the bus bars 50, 50A, and 50B of the first to third embodiments, and the corresponding portions are denoted by the same reference numerals and description thereof is omitted.

-Embodiment 5-
FIG. 13 is an external perspective view of a bus bar as Embodiment 4 used in the assembled battery of the present invention. The bus bar 50D of the fifth embodiment can be applied to the secondary batteries 1 and 1A constituting the assembled batteries 100 and 100A shown in the first and second embodiments.
In the bus bar 50D, similarly to the bus bar 50C shown in the fourth embodiment, the heat dissipating fins 52b are not formed in a plate shape but in a column shape. The difference from the fourth embodiment is that, in the bus bar 50C, the heat dissipating fins 52b are arranged in a grid pattern, whereas in the bus bar 50D of the fifth embodiment, the heat dissipating fins 52c are shifted by half a pitch every other row. It is a point arranged in.

  Even in the assembled battery in which the secondary batteries 1 and 1A are connected using such a bus bar 50D, the same effect as that obtained when the bus bar 50C is used is produced.

Embodiment 6
14-16 is a figure for demonstrating Embodiment 6 of the assembled battery of this invention, FIG. 14 is an external appearance perspective view as other embodiment of the secondary battery used for the assembled battery of this invention. FIG. 15 is an enlarged perspective view of a bus bar used in the assembled battery configured using the secondary battery illustrated in FIG. 14. FIG. 16A is a plan view of the bus bar shown in FIG. 15, and FIG. 16B is a side view of the bus bar shown in FIG.
In the secondary battery 1B illustrated in FIG. 14, the terminals 61A and 71A of the external positive electrode and the external negative electrode do not have a bolt structure, but have a simple rectangular parallelepiped shape. The terminals 61A and 71A of the external positive electrode and the external negative electrode are fixed to the battery cover 3 via an insulating plate 64A attached to an opening provided in the battery cover 3 of the secondary battery 1B.

The terminals 61A and 71A of the external positive electrode and the external negative electrode have flat upper end surfaces 66 and 76, respectively, and the heights of the upper end surfaces 66 and 76 from the upper surface 3a of the battery lid 3 are the same.
A safety valve 16 </ b> A is provided at the center of the battery lid 3. The safety valve 16A is different in shape from the safety valve 16 in the first embodiment, but has the same function. In addition, a liquid injection plug 15A is provided between the safety valve 16A of the battery lid 3 and the external negative electrode terminal 71A.
In addition, “+” indicating a positive electrode is marked on the outer side of the external positive electrode terminal 61A of the battery lid 3, and “−” indicating a negative electrode is marked on the outer side of the negative electrode external terminal 71A.

In the bus bar 50E, no through hole is provided in the attachment portion 55a of the base portion 55, and the attachment portion 55a is a simple flat plate portion. Other structures are the same as those of the bus bar 50 shown in the first embodiment.
The bus bar 50E mounts the mounting portion 55a of the base portion 55 on the upper end surfaces 66 and 76 of the external positive and negative terminals 61A and 71A, and for example, external positive and negative electrodes by a welding method such as ultrasonic welding or arc welding. Are joined to the terminals 61A and 71A.

  When the bus bar 50E is joined to the external positive and negative terminals 61A and 71A, the mounting portion 55a of the bus bar 50E is disposed in parallel with the upper surface 3a of the battery lid 3, and the heat dissipating fins are disposed on the mounting portion 55a. 52 is not provided. For this reason, since it can join from the upper direction of the battery cover 3 visually recognizing the attachment part 55a, workability | operativity improves.

Thus, the assembled battery of this invention can be comprised using the secondary battery 1B in which the terminal 61A, 71A of an external positive electrode and a negative electrode does not have a volt | bolt structure.
15 and 16, the bus bar 50 </ b> E is illustrated as having the heat dissipating fins 52 similar to the bus bar 50 illustrated in FIGS. 7 and 8 as the first embodiment. However, the bus bars 50A to 50D shown in the second to fifth embodiments are also applicable to the secondary battery 1B illustrated in FIG. 14 if the through hole 53 is not provided in the mounting portion 51a of the base portion 51. Is possible.

  As described above, in the battery pack according to the embodiment of the present invention, the bus bars 50 and 50A to 50E are provided with the mounting portions 51a and 55a and the heat radiation fins 52 and 52a provided substantially perpendicular to the mounting portions 51a and 55a. 52c, and the attachment portions 51a and 55a can increase the contact area with the terminals 61, 66, 71, and 76 of the external positive electrode and the external negative electrode. For this reason, the electrical resistance between the bus bars 0, 50A to 50E and the secondary batteries 1, 1A, 1B can be reduced.

  The material of the bus bars 50, 50A to 50E is not limited to copper, and nickel plating may be applied to the copper surface. In addition to copper, nickel, aluminum, stainless steel, or the like can be used. Further, a clad material obtained by diffusion bonding of different metals may be used.

  In each embodiment, six secondary batteries 1, 1A, and 1B constituting the assembled battery are illustrated, but the number of secondary batteries 1, 1A, and 1B is not limited at all.

  In the above embodiment, the secondary batteries 1, 1 </ b> A, and 1 </ b> B are exemplified as a structure in which the front surface and the back surface are in close contact. However, the secondary batteries 1, 1 </ b> A, 1 </ b> B may be arranged to be spaced apart from each other so that the cooling medium flows between the secondary batteries 1, 1 </ b> A, 1 </ b> B.

  In the said embodiment, the case of the lithium ion secondary battery was demonstrated. However, the present invention can also be applied to a secondary battery using a water-soluble electrolyte such as a nickel metal hydride battery, a nickel cadmium battery, or a lead storage battery.

  In addition, the present invention can be applied in various modifications within the scope of the invention. In short, a bus bar having a plurality of heat dissipating fins is provided with a mounting portion parallel to the upper surface of the battery cover. Any device may be used as long as the external positive terminal and the external negative terminal of the secondary battery are connected by the mounting portion.

DESCRIPTION OF SYMBOLS 1, 1A, 1B Secondary battery 3 Battery cover 3a Upper surface 4 Battery can 21 Positive electrode current collecting plate 31 Negative electrode current collecting plate 40 Power generation element 41 Positive electrode 42 Negative electrode 50, 50A-50E Bus bar 51, 55 Base part 51a, 55a Installation Portions 52, 52a to 52c Fins for heat dissipation 52a Upper end 53 Through-hole 61, 61A External positive terminal (positive terminal)
61c, 71c Upper end portion 66, 76 Upper end surface 71, 71A External negative terminal (negative terminal)

Claims (11)

A power generation element including a positive electrode and a negative electrode is accommodated in a battery container constituted by a battery lid and a battery can, and a positive electrode terminal and a negative electrode terminal connected to the positive electrode and the negative electrode, respectively, are inside the battery lid. A plurality of secondary batteries provided protruding from the outside,
A bus bar connecting the positive electrode and the negative electrode terminal of each of the secondary batteries,
The bus bar includes a flat mounting portion disposed substantially parallel to the upper surface of the battery lid, and a plurality of heat dissipating fins provided substantially perpendicular to the mounting portion.   2. The assembled battery according to claim 1, wherein the positive electrode terminal and the negative electrode terminal have a male screw portion, the bus bar has a through-hole through which the male screw portion is inserted, and the bus bar has The assembled battery, wherein the through hole is inserted into the male screw portion of the positive electrode terminal and the negative electrode terminal, and is fixed to the positive electrode terminal or the negative electrode terminal by a nut.   3. The assembled battery according to claim 2, wherein an upper end of each of the heat dissipating fins of the bus bar is formed at a height that forms substantially the same plane as the upper end portions of the positive electrode terminal and the negative electrode terminal. Assembled battery.   2. The assembled battery according to claim 1, wherein the positive electrode terminal and the negative electrode terminal have upper end surfaces that are substantially parallel to an upper surface of the battery lid, and the bus bars are connected to the attachment portion by welding. An assembled battery, which is joined to the upper end surface of the terminal.   5. The assembled battery according to claim 1, wherein each bus bar connects an outer peripheral edge of the through hole through which the positive terminal is inserted and an outer peripheral edge of the through hole through which the negative terminal is inserted. A battery assembly comprising a flat portion region corresponding to a straight region, wherein the heat dissipating fins are not provided in the flat portion region.   6. The assembled battery according to claim 1, wherein the plurality of heat dissipating fins of each bus bar have a plate-like shape extending in parallel to each other. 7.   The assembled battery according to claim 6, wherein the plurality of heat dissipating fins of each bus bar extend in parallel to a direction orthogonal to a straight line connecting the positive electrode terminal and the negative electrode terminal provided on each battery lid. An assembled battery characterized by being released.   8. The assembled battery according to claim 7, wherein the mounting portion of each bus bar is disposed outside a region between the positive electrode terminal and the negative electrode terminal provided on the battery lid. Assembled battery.   The assembled battery according to claim 7, wherein the mounting portion of each bus bar is disposed in a region between the positive terminal and the negative terminal provided on the battery cover. battery.   7. The assembled battery according to claim 6, wherein the plurality of heat dissipating fins of each bus bar are extended in parallel with a straight line connecting the positive electrode terminal and the negative electrode terminal provided on each battery cover. A battery pack featuring the features.   6. The assembled battery according to claim 1, wherein the plurality of heat dissipating fins of each bus bar are each formed in a columnar shape.

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