JP2012178271A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of reducing the weight of a battery pack composed of connecting two or more secondary batteries.SOLUTION: A battery pack 10 includes two or more batteries 30 each of which includes a case in which an electrode body is stored, and a cathode terminal 50 and an anode terminal 60 arranged on the same side 31a of the case and electrically connected to the electrode body. At least two electrodes 30 connected in series are arranged so that the side 31a to which the cathode terminal 50 of one battery 30 is attached and the side 31a to which the anode terminal 60 of the other battery 30 is attached are opposed to each other.

Description

  The present invention relates to an assembled battery in which two or more secondary batteries are connected.

  Generally, in a battery pack in which a plurality of secondary batteries are connected, one positive terminal and the other negative terminal of adjacent secondary batteries are connected in series by a bus bar. On the other hand, for the purpose of reducing the number of parts, a configuration is known in which terminals of adjacent batteries are connected without using a bus bar (see Patent Document 1).

  This configuration includes a flat battery in which an interconnect portion to be directly connected to a terminal of an adjacent battery is formed integrally with a positive terminal or a negative terminal. The interconnecting portion has one end connected to a terminal protruding from the side surface of the flat battery casing, and the other end extending in a direction perpendicular to the protruding direction of the terminal. The plurality of flat batteries are arranged on the same plane so that the side surfaces provided with the terminals face the same direction. Then, an interconnecting portion that is formed at a terminal of one flat battery of two adjacent flat batteries and extends toward a terminal of the other flat battery is connected to the other terminal, thereby adjacent 2 Two flat batteries are connected in series.

JP 2005-332627 A

  In the conventional structure described above, the flat battery is arranged so that the side surface provided with the terminals faces the same direction. That is, in the two adjacent flat batteries, the side surfaces provided with the terminals are arranged on the same plane. And both were connected in series via the interconnection part extended between the terminals of two adjacent flat batteries. Therefore, the conventional assembled battery has room for improvement in reducing the weight of the assembled battery.

  This invention is made | formed in view of such a subject, The objective is to provide the technique which can aim at the weight reduction of the assembled battery in which two or more secondary batteries are connected.

  One embodiment of the present invention is an assembled battery. The assembled battery includes two or more secondary batteries each having a casing in which an electrode body is accommodated, and a positive terminal and a negative terminal that are provided on the same side surface of the casing and are electrically connected to the electrode body. The at least two secondary batteries connected in series are arranged such that the side surface provided with the positive electrode terminal of one secondary battery faces the side surface provided with the negative electrode terminal of the other secondary battery. It is characterized by.

  According to this aspect, the positive electrode terminal of one secondary battery and the negative electrode terminal of the other secondary battery are connected as compared with the conventional structure in which the battery is arranged so that the side surface provided with the terminal faces the same direction. The length of the terminal connecting member to be performed can be shortened. Alternatively, the terminal connection member can be omitted. Therefore, the weight reduction of the assembled battery formed by connecting two or more secondary batteries can be achieved.

  In the above-described embodiment, the secondary battery may have a flat shape having two main surfaces, and the side surface may be a surface connected to the two main surfaces.

  In any one of the aspects described above, at least two secondary batteries may be arranged on the same plane. Alternatively, the at least two secondary batteries may be refracted around an axis passing through the connection portion between the positive electrode terminal and the negative electrode terminal and the housing of the two secondary batteries.

  In any one of the above-described embodiments, the other secondary battery disposed above the main surface of at least one of the two secondary batteries, the other secondary battery, and the positive terminal of the one secondary battery And a terminal connecting member for connecting the negative terminals and the negative terminals in parallel.

  In the aspect described above, a first battery layer in which a plurality of secondary batteries are connected in series, and a plurality of secondary batteries disposed above the main surface of each secondary battery in the first battery layer are connected in series. A plurality of terminal connections for connecting in parallel the positive terminals and the negative terminals of the second battery layer, each secondary battery of the first battery layer, and each secondary battery of the second battery layer corresponding to each secondary battery. A terminal connection member for connecting terminals serving as one terminal in each of the series connection of the first battery layer and the series connection of the second battery layer, and connecting the terminals serving as the other terminal At least one of the terminal connection members may have a larger cross-sectional area in a direction perpendicular to a straight line passing through the terminals connected by the terminal connection member than other terminal connection members.

  In any one of the aspects described above, the positive electrode terminal and the negative electrode terminal may face each other and be detachably connected. Further, in any of the above-described aspects, the positive electrode terminal and the negative electrode terminal face each other and are connected so as to be rotatable about an axis passing through the connection portion between the positive electrode terminal and the negative electrode terminal and the housing of the two secondary batteries. May be. Further, in any of the above-described aspects, the positive electrode terminal and the negative electrode terminal may face each other and be in direct contact with each other.

  In any of the above-described aspects, the assembled battery may be mounted on an automobile.

  According to the present invention, it is possible to reduce the weight of an assembled battery in which two or more secondary batteries are connected.

FIG. 1A is a plan view showing a schematic structure of the assembled battery according to the embodiment. FIG. 1B is a perspective view showing a schematic structure of the assembled battery according to the embodiment. It is sectional drawing which shows schematic structure of a battery. It is a perspective view which shows schematic structure of the refractive part vicinity of an assembled battery. It is a perspective view which shows schematic structure of the assembled battery with which the refractive part and the plane part were combined. FIG. 5A shows a schematic structure of an assembled battery having a first battery layer and a second battery layer composed of a plurality of batteries connected in series, and batteries of each battery layer are connected in parallel between the layers. FIG. FIG. 5B is a plan view showing a schematic structure of the first battery layer. FIG. 5C is a plan view showing a schematic structure of the second battery layer. FIG. 6A is a plan view showing a schematic structure of a part of a conventional assembled battery having a structure in which a plurality of batteries are connected in series and in parallel. FIG. 6B is a circuit diagram illustrating a circuit configuration of the assembled battery illustrated in FIG. FIG. 6C is a side view showing a partial schematic structure of the assembled battery according to Embodiment 1 having a structure in which a plurality of batteries are connected in series and in parallel. FIG. 6D is a circuit diagram illustrating a circuit configuration of the assembled battery illustrated in FIG. FIG. 7A and FIG. 7B are perspective views showing a schematic structure of a metal surface fastener as an example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  FIG. 1A is a plan view showing a schematic structure of the assembled battery according to the embodiment. FIG. 1B is a perspective view showing a schematic structure of the assembled battery according to the embodiment. As shown in FIGS. 1A and 1B, the assembled battery 10 includes two or more batteries 30 having a positive electrode terminal 50 and a negative electrode terminal 60. In the present embodiment, a total of six batteries 30 a to 30 f are connected in series to form the assembled battery 10. Hereinafter, the batteries 30a to 30f are collectively referred to as the battery 30 as appropriate. Note that the number of the batteries 30 is not particularly limited.

  FIG. 2 is a cross-sectional view showing a schematic structure of the battery. FIG. 2 corresponds to a cross-sectional view along a plane passing through the line AA in FIG. The battery 30 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery, and an electrode body 32 in which positive and negative electrodes are wound in a spiral shape in an outer can (housing) 31 includes an outer can 31. It is accommodated transversely to the can axis direction. The opening of the outer can 31 is sealed by a sealing plate 33 constituting the side surface 31 a of the outer can 31. The sealing plate 33 is provided with a positive electrode terminal 50 and a negative electrode terminal 60 that protrude outward from the battery 30. The sealing plate 33 is formed with a gas discharge valve (not shown). The exterior can 31 is impregnated with a nonaqueous electrolyte.

  The positive electrode terminal 50 has a substantially columnar shape, and is fitted into the positive electrode opening 33 a of the sealing plate 33 with the gasket 34 in contact with the side surface. The positive electrode terminal 50 is connected to the positive electrode tab member 53 on the battery inner side of the sealing plate 33. At the end of the positive electrode terminal 50 on the inside of the battery, a recess 51 is provided such that a side wall is formed along the positive electrode opening 33a. The positive electrode terminal 50 is fixed to the positive electrode tab member 53 by caulking so that the edge portion of the recess 51 is widened. A convex portion 50a extending in the circumferential direction is formed on the side surface of the end portion of the positive electrode terminal 50 protruding outward from the battery. Accordingly, the positive terminal 50 has a male terminal structure.

  An insulating plate 35 is provided between the positive electrode tab member 53 and the battery inner surface of the sealing plate 33. The insulating plate 35 and the gasket 34 are in contact with each other at the positive electrode opening 33a. Thereby, the positive electrode tab member 53 and the positive electrode terminal 50 are insulated from the sealing plate 33. The positive electrode tab member 53 is connected to the positive electrode current collector plate group 32 a protruding from one end face of the electrode body 32. The positive electrode current collector plate group 32 a is a bundle of a plurality of positive electrode current collector plates protruding from one end face of the electrode body 32.

  The negative electrode terminal 60 has a substantially columnar shape, and is fitted into the negative electrode opening 33 b of the sealing plate 33 with the gasket 34 in contact with the side surface. The negative electrode terminal 60 is connected to the negative electrode tab member 62 inside the sealing plate 33 on the battery side. A recess 61 is formed at the end of the negative electrode terminal 60 so that a side wall is formed along the negative electrode opening 33b. The negative electrode terminal 60 is fixed to the negative electrode tab member 62 by caulking so that the edge portion of the recess 61 is widened. At the end of the negative electrode terminal 60 protruding outward from the battery, a bowl-shaped space 60a is formed along the shape of the battery outer side end of the positive electrode terminal 50. Therefore, the negative electrode terminal 60 has a female terminal structure.

  An insulating plate 35 is provided between the negative electrode tab member 62 and the battery inner surface of the sealing plate 33. The insulating plate 35 and the gasket 34 are in contact with each other at the negative electrode opening 33b. Thereby, the negative electrode tab member 62 and the negative electrode terminal 60 are insulated from the sealing plate 33. The negative electrode tab member 62 is connected to the negative electrode current collector plate group 32 b protruding from the other end face of the electrode body 32. The negative electrode current collector plate group 32 b is a bundle of a plurality of negative electrode current collector plates protruding from the other end face of the electrode body 32.

  In the assembled battery 10, at least two batteries 30 connected in series have a side surface 31 a provided with the positive electrode terminal 50 of one battery 30 and a side surface 31 a provided with the negative electrode terminal 60 of the other battery 30 face each other. Has been placed. As described above, the side surface 31a provided with the positive electrode terminal 50 of one battery 30 and the side surface 31a provided with the negative electrode terminal 60 of the other battery 30 are arranged to face each other, so that the side surfaces 31a face the same direction. Compared to the conventional structure, the length of the terminal connection member interposed between the positive electrode terminal 50 and the negative electrode terminal 60 such as the above-described interconnection portion can be shortened. Therefore, the weight of the assembled battery 10 can be reduced.

  In the present embodiment, as shown in FIGS. 1A and 1B, in the batteries 30a and 30b connected in series, the region in the vicinity of the negative electrode terminal 60 on the side surface 31a of the battery 30a and the side surface 31a of the battery 30b. The region in the vicinity of the positive electrode terminal 50 is disposed so as to be opposed. Further, in the batteries 30b and 30c connected in series, a region in the vicinity of the negative electrode terminal 60 on the side surface 31a of the battery 30b and a region in the vicinity of the positive electrode terminal 50 on the side surface 31a of the battery 30c are arranged to face each other. Further, in the batteries 30c and 30d connected in series, a region in the vicinity of the negative electrode terminal 60 on the side surface 31a of the battery 30c and a region in the vicinity of the positive electrode terminal 50 on the side surface 31a of the battery 30d are disposed to face each other. In addition, in the batteries 30d and 30e connected in series, a region near the negative electrode terminal 60 on the side surface 31a of the battery 30d and a region near the positive electrode terminal 50 on the side surface 31a of the battery 30e are arranged to face each other. In addition, in the batteries 30e and 30f connected in series, a region in the vicinity of the negative electrode terminal 60 on the side surface 31a of the battery 30e and a region in the vicinity of the positive electrode terminal 50 on the side surface 31a of the battery 30f are disposed to face each other.

  Furthermore, in this embodiment, the negative electrode terminal 60 of the battery 30a and the positive electrode terminal 50 of the battery 30b, the negative electrode terminal 60 of the battery 30b and the positive electrode terminal 50 of the battery 30c, the negative electrode terminal 60 of the battery 30c and the positive electrode terminal 50 of the battery 30d, the battery The negative terminal 60 of 30d and the positive terminal 50 of the battery 30e, and the negative terminal 60 of the battery 30e and the positive terminal 50 of the battery 30f are opposed to each other. Therefore, the length of the terminal connection member can be further shortened. Therefore, further weight reduction of the assembled battery 10 is possible.

  In the present embodiment, the positive electrode terminal 50 and the negative electrode terminal 60 are connected by accommodating the end including the convex portion 50 a of the positive electrode terminal 50 in the flange-shaped space 60 a of the negative electrode terminal 60. Specifically, the side wall forming the bowl-shaped space 60a of the negative electrode terminal 60 can be elastically deformed. When the end of the positive electrode terminal 50 and the end of the negative electrode terminal 60 are pressed against each other, the side wall of the bowl-shaped space 60a Is expanded by the convex portion 50a, and the end portion of the positive electrode terminal 50 is accommodated in the bowl-shaped space 60a. The positive electrode terminal 50 and the negative electrode terminal 60 can be rotated relative to each other around the central axis, with the central axes overlapping with each other while being connected to each other. Further, when a force in a direction away from each other is applied to the positive electrode terminal 50 and the negative electrode terminal 60 in a state where the positive electrode terminal 50 and the negative electrode terminal 60 are connected, the side walls forming the bowl-shaped space 60a are spread outward by the convex portions 50a. Thus, the end portion of the positive electrode terminal 50 exits from the bowl-shaped space 60 a of the negative electrode terminal 60.

  That is, the positive electrode terminal 50 and the negative electrode terminal 60 are in direct contact with each other without using the above-described bus bar or interconnecting portion. Therefore, further weight reduction of the assembled battery 10 is possible. The positive terminal 50 and the negative terminal 60 are detachably connected. Therefore, the battery 30 can be easily attached to and detached from the assembled battery 10. Thereby, the maintenance of the assembled battery 10 including attachment / detachment or replacement of each battery 30 can be easily performed.

  The positive terminal 50 ′ of the battery 30a serving as one end of the series connection of the plurality of batteries 30 and the negative terminal 60 ′ of the battery 30f serving as the other end are connected to an external load via a wiring routed to the outside. (Both not shown) can be connected.

  Battery 30 has a flat shape with two main surfaces. The positive terminal 50 and the negative terminal 60 are provided on the same side surface 31a connected to the two main surfaces. Thus, since the battery 30 is a flat battery and the side surfaces 31a provided with the terminals are arranged to face each other and the batteries 30 are connected in series, the overall shape of the assembled battery 10 is a planar shape. Therefore, the assembled battery 10 according to the present embodiment can be accommodated in a space having a small height. For example, the assembled battery 10 can be suitably mounted on an automobile in which it is easy to secure a space in the plane direction as a space for housing the battery but it is difficult to secure a space in the height direction.

  In addition, at least two batteries 30 connected in series are arranged on the same plane. By arranging the two batteries 30 on the same plane, it is possible to easily realize a space design with little dead space in the accommodation space of the two batteries 30. Therefore, the dead space in the accommodation space of the assembled battery 10 can be reduced. In the present embodiment, the battery 30a and the battery 30b, the battery 30b and the battery 30c, the battery 30c and the battery 30d, the battery 30d and the battery 30e, the battery 30e and the battery 30f are arranged on the same plane. That is, all the batteries 30 are arranged on the same plane. Therefore, it is possible to easily realize a space design that minimizes the dead space in the accommodation space of the assembled battery 10.

  FIG. 3 is a perspective view showing a schematic structure in the vicinity of the refracting portion of the assembled battery. FIG. 4 is a perspective view showing a schematic structure of an assembled battery in which a refracting portion and a flat portion are combined. As described above, the substantially columnar positive electrode terminal 50 and the negative electrode terminal 60 overlap with each other in the state where they are connected to each other, and are rotatable around the center axis. That is, the positive electrode terminal 50 and the negative electrode terminal 60 are connected so as to be rotatable about an axis X passing through the connecting portion 70 between the positive electrode terminal 50 and the negative electrode terminal 60 and the outer can 31 of the two batteries 30. The axis X is an axis that overlaps the central axis of each of the positive electrode terminal 50 and the negative electrode terminal 60. Therefore, the assembled battery 10 can take various shapes by rotating the battery 30 about the axis X. Thereby, the mounting arrangement of the assembled battery 10 can be set more freely.

  For example, as shown in FIG. 3, the assembled battery 10 can be provided with a refracting portion 12 by refracting the two batteries 30 b and 30 c around the axis X of the batteries 30 b and 30 c. The angle of the refracting portion 12 can be freely set.

  For example, as shown in FIG. 4, in the assembled battery 10, the batteries 30d, 30e, and 30f are arranged on a plane, the batteries 30a and 30b are arranged on another plane, and the battery 30b and the battery 30c are 90 ° from each other. The battery 30c and the battery 30d are refracted, and a structure in which the battery 30d is refracted by 90 °, that is, a structure that is folded back by the battery 30c can be obtained.

  Further, the assembled battery 10 according to the present embodiment includes another battery 30 disposed above the main surface of at least one of the two batteries 30 connected in series, the other battery 30, and one battery. A bus bar 80 (terminal connecting member) for connecting the 30 positive terminals 50 and the negative terminals 60 in parallel can be further provided.

  FIG. 5A shows a schematic structure of an assembled battery having a first battery layer and a second battery layer composed of a plurality of batteries connected in series, and batteries of each battery layer are connected in parallel between the layers. FIG. FIG. 5B is a plan view showing a schematic structure of the first battery layer. FIG. 5C is a plan view showing a schematic structure of the second battery layer. In FIG. 5A, the batteries 30b, 30d, and 30f and the other batteries 30h, 30j, and 30l disposed above the main surfaces of the batteries 30b, 30d, and 30f are indicated by broken lines.

  In the present embodiment, as shown in FIGS. 5A, 5B, and 5C, the battery 30g is arranged in a direction perpendicular to the main surface of the battery 30a (above the main surface). . The main surfaces of the battery 30a and the battery 30g are opposed to each other. Similarly, the battery 30h is above the main surface of the battery 30b, the battery 30i is above the main surface of the battery 30c, the battery 30j is above the main surface of the battery 30d, the battery 30k is above the main surface of the battery 30e, and the battery 30f. Batteries 30l are arranged above the main surface. Thereby, the 1st battery layer 14 which consists of batteries 30a-30f and the 2nd battery layer 16 which consists of batteries 30g-30l are formed. The number of battery layers is not particularly limited, and may be three or more.

  The batteries 30g to 30l have the same shape as the batteries 30a to 30f. The arrangement of the batteries 30g to 30l is the same as that of the batteries 30a to 30f. That is, the side surface of the battery 30g on which the negative electrode terminal 60 is provided and the side surface of the battery 30h on which the positive electrode terminal 50 is provided are opposed to each other. Further, the side surface of the battery 30h provided with the negative electrode terminal 60 and the side surface of the battery 30i provided with the positive electrode terminal 50, the side surface of the battery 30i provided with the negative electrode terminal 60 and the side surface of the battery 30j provided with the positive electrode terminal 50, The side surface of the battery 30j on which the negative electrode terminal 60 is provided, the side surface on which the positive electrode terminal 50 of the battery 30k is provided, the side surface on which the negative electrode terminal 60 of the battery 30k is provided, and the side surface on which the positive electrode terminal 50 of the battery 30l is provided. Opposed.

  Between the negative terminal 60 of the battery 30a and the positive terminal 50 of the battery 30b, between the negative terminal 60 of the battery 30b and the positive terminal 50 of the battery 30c, and between the negative terminal 60 of the battery 30c and the positive terminal 50 of the battery 30d. Between the negative terminal 60 of the battery 30d and the positive terminal 50 of the battery 30e and between the negative terminal 60 of the battery 30e and the positive terminal 50 of the battery 30f, one end of the strip-shaped bus bar 80 is disposed. Has been. The tip of the positive terminal 50 ′ of the battery 30a and the tip of the negative terminal 60 ′ of the battery 30f are thicker than the bus bar 80 disposed between the terminals of each battery (the cross-sectional area in the direction perpendicular to the longitudinal direction is larger). One end of the (large) bus bar 80 'is arranged.

  The other end of the bus bar 80 disposed between the negative terminal 60 of the battery 30a and the positive terminal 50 of the battery 30b is disposed between the negative terminal 60 of the battery 30g and the positive terminal 50 of the battery 30h. Has been. Between the negative terminal 60 of the battery 30h and the positive terminal 50 of the battery 30i, the other end of the bus bar 80 disposed between the negative terminal 60 of the battery 30b and the positive terminal 50 of the battery 30c is disposed. . Between the negative terminal 60 of the battery 30i and the positive terminal 50 of the battery 30j, the other end portion of the bus bar 80 disposed between the negative terminal 60 of the battery 30c and the positive terminal 50 of the battery 30d is disposed. . Between the negative terminal 60 of the battery 30j and the positive terminal 50 of the battery 30k, the other end portion of the bus bar 80 disposed between the negative terminal 60 of the battery 30d and the positive terminal 50 of the battery 30e is disposed. . Between the negative terminal 60 of the battery 30k and the positive terminal 50 of the battery 301, the other end of the bus bar 80 disposed between the negative terminal 60 of the battery 30e and the positive terminal 50 of the battery 30f is disposed. Yes.

  The other end of the bus bar 80 ′ disposed at the tip of the positive terminal 50 ′ of the battery 30 a is disposed at the tip of the positive terminal 50 ′ of the battery 30 g serving as one terminal in the second battery layer 16. Yes. The other end of the bus bar 80 ′ disposed at the tip of the negative electrode terminal 60 ′ of the battery 30f is arranged at the tip of the negative electrode terminal 60 ′ of the battery 30l serving as the other terminal in the second battery layer 16. Yes.

  The bus bar 80 has a male terminal portion 82 having the same shape as the tip portion of the positive electrode terminal 50 on the first main surface at both ends, and has the same shape as the tip portion of the negative electrode terminal 60 on the second main surface at both ends. Female terminal portion 84. The bus bar 80 ′ disposed at the tip of the positive terminal 50 ′ of the battery 30 a and the battery 30 g has a female terminal 84 on one main surface of both ends. The bus bar 80 ′ disposed at the tip of the negative electrode terminal 60 ′ of the battery 30 f and the battery 30 l has a male terminal portion 82 on one main surface at both ends. When the battery layers are three or more layers, the male terminal portions 82 and the female terminal portions 84 corresponding to the number of layers are provided along the longitudinal direction of the bus bars 80 and 80 '. In addition, the bus bar 80 ′ has a connecting portion 86 that extends perpendicularly to the longitudinal direction at a substantially intermediate position in the longitudinal direction and to which external wiring is connected.

  The negative terminals 60 of the batteries 30 a to 30 e are detachably and rotatably connected to a male terminal portion 82 provided on the first main surface at one end of the bus bar 80. Further, the positive terminals 50 of the batteries 30 b to 30 f are detachably and rotatably connected to a female terminal 84 provided on the second main surface of one end of the bus bar 80. Therefore, in the batteries 30 a to 30 f, one positive terminal 50 and the other negative terminal 60 of the two batteries 30 connected in series are connected in series via one end of the bus bar 80.

  Further, the negative terminals 60 of the batteries 30 g to 30 k are detachably and rotatably connected to a male terminal portion 82 provided on the first main surface of the other end of the bus bar 80. Further, the positive terminals 50 of the batteries 30 h to 30 l are detachably and rotatably connected to a female terminal 84 provided on the second main surface of the other end of the bus bar 80. Therefore, in the batteries 30 g to 30 l, one positive terminal 50 and the other negative terminal 60 of the two batteries 30 connected in series are connected in series via the other end of the bus bar 80.

  Furthermore, the positive terminal 50 'of the battery 30a and the battery 30g is detachably and rotatably connected to a female terminal 84 provided at one or the other end of the bus bar 80'. Further, the negative terminal 60 'of the battery 30f and the battery 30l is detachably and rotatably connected to a male terminal 82 provided at one or the other end of the bus bar 80'.

  The battery 30 of the first battery layer 14 and the battery 30 of the second battery layer 16 are connected in parallel by such connection of the bus bars 80, 80 ′. Specifically, the positive terminals 50 ′ and negative electrodes 60 of the batteries 30a and 30g, the positive terminals 50 and negative terminals 60 of the batteries 30b and 30h, the positive terminals 50 and negative electrodes of the batteries 30c and 30i, and the negative electrodes. The terminals 60, the positive terminals 50 of the batteries 30d and 30j and the negative terminals 60, the positive terminals 50 of the batteries 30e and 30k and the negative terminals 60, the positive terminals 50 of the batteries 30f and 30l, and the negative terminals 60 'Is connected in parallel by bus bars 80 and 80', respectively.

  FIG. 6A is a plan view showing a schematic structure of a part of a conventional assembled battery having a structure in which a plurality of batteries are connected in series and in parallel. FIG. 6B is a circuit diagram illustrating a circuit configuration of the assembled battery illustrated in FIG. FIG. 6C is a side view showing a partial schematic structure of the assembled battery according to Embodiment 1 having a structure in which a plurality of batteries are connected in series and in parallel. FIG. 6D is a circuit diagram illustrating a circuit configuration of the assembled battery illustrated in FIG.

  As shown in FIGS. 6 (A) and 6 (B), the conventional assembled battery 10 has a plurality of units composed of a plurality of batteries 30 connected in parallel, and the plurality of units are connected in series. Have Specifically, the plurality of batteries 30 are arranged in parallel at predetermined intervals so that the longitudinal directions of the batteries 30 are substantially parallel in a plan view. The positive electrode terminal 50 and the negative electrode terminal 60 of each battery 30 are directed upward. Then, the positive terminals 50 and the negative terminals 60 of the three adjacent batteries 30 are connected by the bus bar 80 to form a unit composed of the three batteries 30. The bus bar 80 is fixed to the positive terminal 50 and the negative terminal 60 with screws.

  Then, the bus bar 80 that connects the positive terminals 50 of one unit in the two adjacent units and the bus bar 80 that connects the negative terminals 60 of the other unit are connected, and the two adjacent units are connected in series. Has been. In the conventional assembled battery 10 shown in FIG. 6A, the bus bar 80 that connects the positive terminals 50 of one unit and the bus bar 80 that connects the negative terminals 60 of the other unit are formed integrally. It consists of one bus bar 80. Therefore, the positive terminals 50 of the three batteries 30 constituting one unit and the negative terminals 60 of the three batteries 30 constituting the other unit are connected to this one bus bar. The number of batteries 30 constituting each unit is not limited to three.

  On the other hand, as shown in FIG. 6C and FIG. 6D, the assembled battery 10 according to the present embodiment includes a first battery layer 14, a second battery layer 16, and a second battery layer composed of a plurality of batteries connected in series. Three battery layers 18 are provided, and batteries 30 of each battery layer are connected in parallel between the layers. The structure in which the batteries 30 are connected in series in each battery layer and the structure in which the batteries in each battery layer are connected in parallel between the battery layers are as described above.

In the conventional battery pack 10, since the units in which the plurality of batteries 30 are connected in parallel are connected in series, the current is concentrated in the portion connecting the units of the bus bar 80. Therefore, heat (RI ² ) corresponding to the resistance R of the bus bar 80 is generated, and there is a possibility that a power loss that cannot be ignored occurs. On the other hand, in the assembled battery 10 according to the first embodiment, the batteries 30 of the battery layers are connected in parallel between the layers. Therefore, if the batteries 30 are homogeneous and there is no potential difference between the batteries, the batteries 30 are connected between the battery layers. In theory, no current flows through the bus bars 80 connected in parallel.

  Actually, since there is often a potential difference between the batteries 30, the bus bar 80 has a current that is equal to the potential between the two batteries 30 connected in parallel. However, this current is extremely smaller than the current flowing through the bus bar 80 in the conventional structure. Therefore, the power loss due to the current passing through the bus bar 80 can be reduced. Moreover, the bus bar 80 can be made thin.

  As shown in FIGS. 5 (A) to 5 (C), a bus bar 80 for connecting in parallel a positive electrode terminal 50 ′ serving as one end of the series connection of the battery layers and a negative electrode terminal 60 ′ serving as the other end. 'Is thicker than the other bus bars 80 because the currents flowing through the battery layers gather. That is, the bus bar 80 ′ is connected by the bus bar 80 ′ and has a cross-sectional area perpendicular to the direction in which adjacent terminals are arranged (cross-sectional area in a direction perpendicular to a straight line passing through the adjacent terminals) as compared to other bus bars 80. large.

  Thus, according to the assembled battery 10 according to the present embodiment, the bus bar 80 ′ connecting the positive electrode terminal 50 ′ and the negative electrode terminal 60 ′ can be made relatively thick and the other bus bars 80 can be made relatively thin. Therefore, reduction of power loss in the assembled battery 10 and weight reduction of the assembled battery 10 can be achieved. If at least one of the bus bars 80 ′ is thicker than the other bus bars 80, the power loss can be reduced as compared with the conventional assembled battery 10.

  In addition, the connection structure of the positive electrode terminal 50 and the negative electrode terminal 60 is not limited to the structure mentioned above. For example, as a detachable connection configuration of the positive electrode terminal 50 and the negative electrode terminal 60, a configuration in which ends of the positive electrode terminal 50 and the negative electrode terminal 60 are connected using a metal surface fastener.

  FIG. 7A and FIG. 7B are perspective views showing a schematic structure of a metal surface fastener as an example. As the metal surface fastener, for example, as shown in FIGS. 7A and 7B, a hook-loop fastener type can be used. The metal surface fastener includes, for example, a hook member 90A fixed to the upper surface of the positive electrode terminal 50 by welding or the like, and a loop member 90B fixed to the upper surface of the negative electrode terminal 60 by welding or the like. The hook member 90A has a plurality of hooks arranged in a matrix on the surface thereof, and the loop member 90B has a plurality of loops arranged in a matrix on the surface thereof. When the upper surface of the positive electrode terminal 50 and the upper surface of the negative electrode terminal 60 are pressed together, the hook of the hook member 90A is hooked on the loop of the loop member 90B, so that the positive electrode terminal 50 and the negative electrode terminal 60 are detachably connected. .

  As described above, in the assembled battery 10 according to the present embodiment, in at least two batteries 30 connected in series, the side surface 31 a provided with the positive terminal 50 of one battery 30 and the negative terminal 60 of the other battery 30. Are arranged so as to face the side surface 31a. Therefore, the length of the terminal connection member interposed between the positive electrode terminal 50 and the negative electrode terminal 60 is shorter than that in the conventional structure in which the battery 30 is arranged so that the side surfaces provided with the terminals face the same direction. can do. Furthermore, the positive electrode terminal 50 and the negative electrode terminal 60 can be directly connected without using a terminal connecting member. Therefore, the weight of the assembled battery 10 can be reduced. Moreover, the manufacturing cost of the assembled battery 10 can be reduced by shortening or omitting the terminal connection member, and an increase in electrical resistance in the terminal connection member can be reduced or avoided.

  The present invention is not limited to the above-described embodiment, and various modifications such as design changes can be added based on the knowledge of those skilled in the art. The embodiment to which such a modification is added is also the present embodiment. It can be included in the scope of the invention.

  10 battery packs, 12 refraction parts, 30, 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h, 30i, 30j batteries, 31 outer can, 31a side surface, 32 electrode body, 50, 50 ′ positive terminal, 60 , 60 ′ negative terminal, 70 connection, X axis.

Claims (10)

Comprising two or more secondary batteries having a housing in which the electrode body is housed, and a positive electrode terminal and a negative electrode terminal which are provided on the same side surface of the housing and are electrically connected to the electrode body;
The at least two secondary batteries connected in series are arranged so that the side surface provided with the positive electrode terminal of one secondary battery faces the side surface provided with the negative electrode terminal of the other secondary battery. A battery pack featuring the features. The secondary battery has a flat shape with two main surfaces,
The assembled battery according to claim 1, wherein the side surface is a surface connected to the two main surfaces.   The assembled battery according to claim 1 or 2, wherein the at least two secondary batteries are arranged on the same plane.   3. The assembled battery according to claim 1, wherein the at least two secondary batteries are refracted around an axis passing through a connection portion between the positive electrode terminal and the negative electrode terminal and a housing of the two secondary batteries. Another secondary battery disposed above the main surface of at least one of the two secondary batteries;
A terminal connecting member for connecting in parallel the positive terminals and negative terminals of the other secondary battery and the one secondary battery;
The assembled battery according to any one of claims 1 to 4, further comprising: A first battery layer in which a plurality of the secondary batteries are connected in series;
A second battery layer in which a plurality of the secondary batteries arranged above the main surface of each secondary battery of the first battery layer are connected in series;
A plurality of terminal connecting members for connecting in parallel the positive terminals and the negative terminals of the secondary batteries of the first battery layer and the secondary batteries of the second battery layer corresponding to the respective secondary batteries;
With
In each of the first battery layer series connection and the second battery layer series connection, the terminal connection member for connecting terminals serving as one terminal, and the terminal connection for connecting terminals serving as the other terminal. The group according to any one of claims 1 to 5, wherein at least one of the members has a cross-sectional area in a direction perpendicular to a straight line passing through a terminal connected by the terminal connection member, as compared with other terminal connection members. battery.   The assembled battery according to claim 1, wherein the positive electrode terminal and the negative electrode terminal face each other and are detachably connected.   2. The positive electrode terminal and the negative electrode terminal face each other and are connected so as to be rotatable about an axis passing through a connection portion between the positive electrode terminal and the negative electrode terminal and a housing of the two secondary batteries. The assembled battery according to any one of 1 to 7.   The assembled battery according to claim 1, wherein the positive electrode terminal and the negative electrode terminal face each other and are in direct contact with each other.   The assembled battery according to any one of claims 1 to 9, which is mounted on an automobile.

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