JP2015064971A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack which allows for enhancement of positioning accuracy by holding a square secondary battery reliably, while suppressing expansion of a battery container.SOLUTION: In a battery pack 200 in which a plurality of square secondary batteries 100 with a flat box type battery container 2 are stacked in the thickness direction (X direction) with a spacer 103 interposed therebetween, the spacer 103 has a first abutting part 120 abutting against the width direction end region R1 of the wide side face 1b of the battery container 2, and a second abutting part 121 abutting against the width direction intermediate region R2 of the wide side face 1b. With regard to the interval of the spacers 103, 103 arranged on both sides of the square secondary batteries 100 in the thickness direction (X direction) to face each other, the interval D2 of the second abutting parts 121, 121 is wider than the interval D1 of the first abutting parts 120, 120.

Description

  The present invention relates to an assembled battery in which a plurality of rectangular secondary batteries are stacked with a spacer interposed therebetween, for example.

  Conventionally, in the field of rechargeable secondary batteries, aqueous batteries such as lead batteries, nickel-cadmium batteries, and nickel-hydrogen batteries have been mainstream. However, as electric appliances become smaller and lighter, lithium ion secondary batteries having a high energy density have attracted attention, and their research, development, and commercialization are rapidly progressing.

  In addition, from the perspective of global warming and depleted fuel, electric vehicles (EV) and hybrid electric vehicles (HEV) that use electric motors to assist a part of the drive have been developed by each automobile manufacturer. Secondary batteries have come to be demanded. As a power source that meets such requirements, high-voltage non-aqueous lithium ion secondary batteries have attracted attention. In particular, prismatic lithium ion secondary batteries have excellent volumetric efficiency when packed into packs, and therefore, there is an increasing expectation for the development of prismatic lithium ion secondary batteries for HEVs or EVs.

  In high current applications such as for HEV or EV, heat generation of the battery is inevitable and the battery needs to be cooled. Generally, a gap is provided between each battery of an assembled battery configured by electrically connecting a plurality of batteries in series and / or in parallel, and cooling of the battery is performed by flowing a cooling medium such as air through the gap. Is going. Moreover, as for each battery which comprises an assembled battery, an electrode material accommodated in a battery container may expand | swell with charge, and a battery container may expand | swell.

  As an assembled battery capable of suppressing the expansion of the battery container, the secondary battery is restrained in a state in which the side surface (pressed surface) of the maximum area among the outer surfaces of each secondary battery is partially compressed. A secondary battery assembly is disclosed (see Patent Document 1 below).

  The secondary battery assembly described in Patent Document 1 suppresses deterioration of the secondary battery by uniformly maintaining the surface pressure of the pressed surface in a secondary battery used at a high rate that repeatedly charges and discharges a large current. And has a contact member and a restraining member as means for solving the problem. The contact member has a plurality of discrete contact portions that contact the pressed surface. The contact portion is formed so as to protrude from the connecting portion toward the pressed surface, and corresponds to a central portion in the winding axis direction of the wound electrode body, and a central region between both offset regions The shape or arrangement itself presses the surface to be pressed more weakly. Specifically, it is described that the contact member is curved so that the top surface contacting the surface to be compressed is concave in the center, and the compression force to the surface to be compressed varies depending on the location in the surface. . On the other hand, it is described that the arrangement of each member is determined so that the contact member does not contact the end portion of the unit cell case and does not press the end portion of the case.

International Publication No. 2011/158341

  In the secondary battery assembly described in Patent Document 1, expansion of the pressed surface is suppressed by the contact member pressing the pressed surface of the unit cell, but the end of the case of the unit cell is not fixed. However, there is a problem in positioning of the unit cell such that the unit cell can be easily moved by vibration when mounted on the vehicle.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an assembled battery that can reliably hold a square secondary battery to improve positioning accuracy and can suppress expansion of a battery container. And

  In order to achieve the above object, the assembled battery of the present invention is an assembled battery in which a plurality of prismatic secondary batteries each having a flat box-type battery container are stacked with a spacer interposed in the thickness direction. A first abutting portion that abuts against a width direction end region of the wide side surface of the battery container; and a second abutting portion that abuts against a width direction intermediate region of the wide side surface; The interval between the spacers arranged opposite to each other in the thickness direction of the secondary battery is characterized in that the interval between the second contact portions is wider than the interval between the first contact portions.

  According to the assembled battery of the present invention, the widthwise end region of the wide side surface of the battery container of the square secondary battery is securely held between the first contact portions of the spacer, and the widthwise intermediate region of the wide side surface. Can be held between the second contact portions, and the expansion of the wide side surface can be suppressed. Further, since the interval between the second contact portions is wider than the interval between the first contact portions, the expansion of the wide side surface is allowed in a range where the battery performance does not deteriorate, and the second contact portion is allowed. The load applied to the intermediate region in the width direction of the wide side surface can be reduced by the contact portion, and an appropriate load can be applied to the wide side surface to prevent a decrease in battery performance.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

The external appearance perspective view of a square secondary battery. 1 is an external perspective view of a prismatic secondary battery module according to Embodiment 1 of the present invention. The perspective view of the square secondary battery and cell holder of the square secondary battery module shown in FIG. The disassembled perspective view of the square secondary battery and cell holder shown in FIG. Sectional drawing which shows the relationship between the spacer of a cell holder shown in FIG. 2, and a square secondary battery. Sectional drawing which shows the relationship between the spacer of a cell holder shown in FIG. 2, and a square secondary battery. The schematic diagram which shows the relationship between the wide side surface of the battery container of the square secondary battery in the square secondary battery module which concerns on Embodiment 2 of this invention, and the 1st contact part of a spacer. The schematic diagram which shows the relationship between the wide side surface of the battery container of the square secondary battery in the square secondary battery module which concerns on Embodiment 3 of this invention, and the 1st contact part of a spacer.

[Embodiment 1]
Hereinafter, Embodiment 1 of the assembled battery of this invention is demonstrated with reference to drawings.

(Square secondary battery)
First, an embodiment of a square secondary battery provided in the assembled battery of the present invention will be described. FIG. 1 is an external perspective view of a prismatic secondary battery 100 of the present embodiment.

  As shown in FIG. 1, the square secondary battery 100 includes a flat box type battery container 2 including a battery can 1 and a battery lid 6. Although not shown in the figure, in the battery container 2, an electrode group produced by winding positive and negative electrodes laminated around a separator as an insulator around a winding axis is housed and arranged.

  The battery can 1 and the battery lid 6 are made of a metal material such as aluminum or an aluminum alloy. The battery can 1 is formed in a flat rectangular box shape with one end opened by, for example, deep drawing a metal material. The battery can 1 is formed in a bottomed cylindrical rectangular parallelepiped shape, and includes a rectangular bottom surface 1d, a pair of wide side surfaces 1b adjacent to each of a pair of long sides of the bottom surface 1d, and a pair of short sides of the bottom surface 1d. And a pair of narrow side surfaces 1c adjacent to each other. An electrode group is accommodated in the battery can 1, and the winding axis direction of the electrode group is parallel to the bottom surface 1 d and the wide side surface 1 b of the battery can 1.

  The battery lid 6 has a rectangular flat plate shape, and is laser-welded to the battery can 1 so as to close the opening of the battery can 1. That is, the battery lid 6 seals the opening of the battery can 1. Further, the battery lid 6 is provided with a positive electrode terminal 51 and a negative electrode terminal 61 which are a pair of electrode terminals via insulators 22 and 24, thereby forming a lid assembly. In addition to the positive electrode terminal 51 and the negative electrode terminal 61, the battery lid 6 has a gas discharge valve 10 that is opened when the pressure in the battery container 2 rises above a predetermined value and discharges the gas in the battery container 2; A liquid injection port 9 for injecting an electrolytic solution into the battery container 2 is disposed.

  The positive electrode terminal 51 and the negative electrode terminal 61 are arranged at positions separated from each other on one side and the other side in the longitudinal direction of the battery lid 6. The positive electrode terminal 51 and the negative electrode terminal 61 include external terminals 52 and 62 arranged outside the battery cover 6 and connection terminals 53 and 63 penetrating the battery cover 6 and having one end electrically connected to the external terminals 52 and 62. Have. The positive external terminal 52 and the connection terminal 53 are made of an aluminum alloy, and the negative external terminal 62 and the connection terminal 63 are made of a copper alloy. Bolts 52a and 62a for fastening the bus bar protrude from the external terminals 52 and 62. The positive electrode terminal 51 is connected to an exposed portion of the positive electrode metal foil provided at one end of the electrode group in the winding axis direction via the external terminal 52, the connection terminal 53, and a current collector plate (not shown) in the battery container 2. The negative electrode terminal 61 is connected to the negative electrode metal foil exposed portion provided at the other end in the winding axis direction of the electrode group via the external terminal 62, the connection terminal 63, and a current collector plate (not shown) in the battery container 2. .

  The gas discharge valve 10 provided in the battery lid 6 is formed by partially thinning the battery lid 6 by press working. A thin member may be attached to the opening of the battery lid 6 by laser welding or the like, and the thin portion of the thin member may be used as a gas discharge valve. The gas discharge valve 10 is heated when the square secondary battery 100 generates heat due to an abnormality such as overcharging, gas is generated in the battery container 2, and the pressure in the battery container 2 increases to reach a predetermined pressure. Thus, the gas inside the battery container 2 is discharged to reduce the internal pressure. Further, the liquid injection port 9 provided in the battery lid 6 is sealed by welding the liquid injection plug 11 after injecting the electrolytic solution.

(Battery)
FIG. 2 is a perspective view showing a prismatic secondary battery module 200 that is an assembled battery of the present embodiment in which a plurality of prismatic secondary batteries 100 are combined. In the following, an orthogonal coordinate system is used in which the thickness direction of the rectangular secondary battery 100, the width direction of the wide side surface 1b, and the height direction of the wide side surface 1b when the module 200 is manufactured are X, Y, and Z directions, respectively. I will explain.

  The module 200 includes a plurality of prismatic secondary batteries 100 stacked in the thickness direction (X direction) of the prismatic secondary battery 100 and a cell holder 91 that holds the prismatic secondary batteries 100 in a stacked state. . The cell holder 91 can be made of, for example, a resin material such as glass epoxy resin, polypropylene, or polybutylene terephthalate resin, or a metal material such as aluminum, copper, or stainless steel.

  The cell holder 91 includes a plurality of intermediate cell holders 92 and a pair of end cell holders 93. Intermediate cell holder 92 is interposed between prismatic secondary batteries 100 adjacent to each other. The end cell holders 93 are arranged at both ends in the stacking direction of the plurality of prismatic secondary batteries 100 stacked in the thickness direction via the intermediate cell holder 92, and the prismatic secondary battery 100 is interposed between the opposing intermediate cell holders 92. Hold. The end cell holder 93 has a configuration in which the intermediate cell holder 92 is roughly divided in half by a plane parallel to the wide side surface 1 b of the prismatic secondary battery 100. Therefore, in the following description, the configuration of the intermediate cell holder 92 will be described in detail, and the description of the configuration of the end cell holder 93 will be omitted as appropriate.

  FIG. 3 is a perspective view showing an assembled state of the pair of intermediate cell holders 92 and 92 and the prismatic secondary battery 100. 4 is a perspective view showing an exploded state of the intermediate cell holders 92 and 92 and the prismatic secondary battery 100 of FIG.

  The intermediate cell holder 92 includes a pair of side plates 111, 111 facing the narrow side surfaces 1 c, 1 c on both sides in the width direction (Y direction) of the battery can 1 of the square secondary battery 100, and a bottom plate facing the bottom surface 1 d of the battery can 1. 112. As shown in FIG. 2, the intermediate cell holder 92 is disposed between the two rectangular secondary batteries 100, 100, so that it passes through the middle of the two rectangular secondary batteries 100, 100 and the wide side surface 1 b of the battery can 1. Have a plane-symmetric shape on a plane parallel to the surface. That is, the side plate 111 and the bottom plate 112 of the intermediate cell holder 92 are connected to the battery can 1 with respect to the narrow side surfaces 1c and 1c and the bottom surfaces 1d and 1d of the two rectangular secondary batteries 100 and 100 disposed on both sides of the intermediate cell holder 92. It faces about half of the thickness direction.

  The pair of side plates 111, 111 are opposed to each other at both ends in the width direction (Y direction) of the wide side surface 1 b of the battery can 1, i.e., the width direction of the square secondary battery 100, and are each half the thickness of the prismatic secondary battery 100. Is extended in the thickness direction (X direction) of the prismatic secondary battery 100. The bottom plate 12 has a width that reaches half of the thickness of the rectangular secondary battery 100 at the lower end in the direction perpendicular to the bottom surface 1d of the battery can 1, that is, the height direction (Z direction) of the wide side surface 1b of the battery can 1. Extending in the thickness direction of the prismatic secondary battery 100, the lower end portions of the pair of side plates 111 are connected. In addition, the pair of opposed intermediate cell holders 92 and 92 disposed on both sides in the thickness direction of the square secondary battery 100 are arranged such that the end portions of the side plates 111 and 111 and the bottom plates 112 and 112 face each other or have a slight gap. By being held open, a space for holding the prismatic secondary battery 100 is formed between them.

  A pair of side plates 111 and 111 facing in the width direction of the wide side surface 1b of the battery can 1 are connected by a plurality of spacers 101, 102, and 103 extending in the width direction of the wide side surface 1b. More specifically, the pair of side plates 111, 111 includes a lower end spacer 101 that connects these lower ends, an upper end spacer 102 that connects these upper ends, and a plurality of intermediate portions that connect these intermediate portions. The spacer 103 is connected. The lower end spacer 101 is connected to the bottom plate 112 at the lower end. The upper end spacer corresponding to the dimension in the Z direction from the upper end bent portion to the lower end of the battery lid 6 among the upper and lower bent portions of the electrode group wound in a flat shape built in the battery can 1. The width in the Z direction of 102 is wider than other spacers. The interval between the lower end spacer 101 and the intermediate spacer 103 and the interval between the upper end spacer 102 and the intermediate spacer 103 are smaller than the interval between the intermediate spacers 103. Each spacer 101, 102, 103 is disposed between two adjacent square secondary batteries 100, 100.

  The side plate 111 has a first opening 111a and a second opening 111b. The first opening 111 a is formed at a position between the lower end spacer 101 and the intermediate spacer 103 and a position between the upper end spacer 102 and the intermediate spacer 103 in the Z direction. The second opening 111b is formed at a position between the intermediate spacers 103 in the Z direction. The first opening 111a and the second opening 111b have the same opening width in the X direction. The opening height in the Z direction of each opening 111a, 111b is larger in the second opening 111b than in the first opening 111a, corresponding to the spacing between the spacers 101, 102, 103. .

  The spacers 101, 102, and 103 are spaced apart from each other in the Z direction, and thereby a plurality of slits extending in the width direction (Y direction) along the wide side surface 1 b of the battery can 1 of the rectangular secondary battery 100. 114 and 115 are formed. The width in the Z direction is relatively small between the lower end spacer 101 and the intermediate spacer 103 and between the upper end spacer 102 and the intermediate spacer 103 corresponding to the distance between the spacers 101, 102, and 103. A narrow first slit 114 is formed. In addition, a second slit 115 having a relatively wide width in the Z direction is formed between the intermediate spacers 103. The first slit 114 communicates with the first opening 111a of the pair of side plates 111, and the second slit 115 communicates with the second opening 111b of the pair of side plates 111. Thereby, a cooling medium is allowed to pass through the slits 114 and 115 so that the wide side surface 1b of the battery can 1 of the rectangular secondary battery 100 can be cooled.

  By interposing the intermediate cell holder 92 having the above configuration, a plurality of prismatic secondary batteries 100 are stacked in the thickness direction, and the end cell holder 93 is disposed outside the prismatic secondary battery 100 at both ends in the stacking direction. A prismatic secondary battery module (assembled battery) 200 is obtained in which a plurality of prismatic secondary batteries 100 are stacked in the thickness direction with spacers 101, 102, and 103 interposed therebetween.

(Spacer)
Next, the intermediate portion spacer 103 provided in the intermediate cell holder 92 and the end cell holder 93 will be described in detail. FIG. 5 is a cross-sectional view showing the relationship between the spacers 103 of the cell holders 92 and 93 and the prismatic secondary battery 100 before the prismatic secondary battery module 200 shown in FIG. 2 is assembled. 6 is a cross-sectional view showing the relationship between the spacers 103 of the cell holders 92 and 93 and the prismatic secondary battery 100 after the prismatic secondary battery module 200 shown in FIG. 2 is assembled.

  As described above, the spacer 103 extends along the width direction (Y direction) of the wide side surface 1b of the battery can 1 constituting the battery case 2 of the rectangular secondary battery 100, and is provided at both ends in the extending direction. The first contact portion 120 and the second contact portion 121 provided between the first contact portions 120 are provided. The first contact portion 120 contacts the width direction end region R1 of the wide side surface 1b of the battery can 1, and the second contact portion 121 contacts the width direction intermediate region R2 of the wide side surface 1b.

  As shown in FIG. 6, the interval between the spacers 103 and 103 arranged opposite to each other in the thickness direction (X direction) of the square secondary battery 100 is larger than the interval D1 between the first contact portions 120 and 120. The distance D2 between the second contact portions 121 and 121 is widened. That is, in the spacer 103, the thickness T 1 of the first contact portion 120 is larger than the thickness T 2 of the second contact portion 121 in the thickness direction of the rectangular secondary battery 100. Accordingly, a step is formed between the first contact portion 120 and the second contact portion 121.

  In addition, the spacers 103 and 103 disposed opposite to each other in the thickness direction of the prismatic secondary battery 100 are such that the surfaces of the first contact portions 120 and 120 and the second contact portions 121 and 121 that face each other are the same. Parallel flat surfaces. In the present embodiment, the first contact portion 120 and the second contact portion 121 are parallel to the width direction and the height direction of the rectangular secondary battery 100, that is, the YZ plane, and the rectangular secondary battery 100. Is perpendicular to the thickness direction, that is, the X direction.

  When the prismatic secondary battery 100 is charged, the electrode group accommodated in the battery container 2 has the largest thickness at the portion facing the central portion of the wide side surface 1b of the battery can 1 mainly due to the expansion of the negative electrode material. Thus, the prismatic secondary battery 100 expands in a convex shape in the thickness direction. Further, gas is generated in the battery container 2 due to a chemical reaction or the like during charging of the square secondary battery 100, and the pressure inside the battery container 2 increases.

  Thereby, as shown in FIG. 5, the battery can 1 has expanded into a convex shape in which the thickness of the central portion of the wide side surface 1b is the largest. In the prismatic secondary battery 100, when the state where the battery can 1 expands in this way, not only may the internal resistance increase and the battery characteristics deteriorate, but also the welded portion of the battery can 1 and the battery lid 6 and the like. There is a risk that the reliability of the system will be lowered. However, if the wide side surface 1b is pressed with an excessive load in order to suppress the expansion of the battery can 1, the battery characteristics of the prismatic secondary battery 100 may be deteriorated. In particular, since the electrode group in the battery can 1 is expanded, the thickness of the battery can 1 in the width direction intermediate region R2 of the wide side surface 1b is the same as the thickness of the battery can 1 in the width direction end region R1. When compressed, an excessive load may be applied to the electrode group.

  Therefore, the prismatic secondary battery module 200 of this embodiment holds the prismatic secondary battery 100 by the cell holders 92 and 93 including the spacer 103, and the prismatic secondary battery 100 is interposed with the spacer 103 in the thickness direction. Laminated. As described above, the spacer 103 includes the first contact portion 120 that contacts the end region R1 in the width direction of the wide side surface 1b of the battery can 1 constituting the battery case 2, and the intermediate region in the width direction of the wide side surface 1b. And a second abutting portion 121 that abuts on R2. Further, in the spacer 103, the thickness of the first contact portion 120 is larger than the thickness of the second contact portion 121 in the thickness direction of the rectangular secondary battery 100. As a result, the distance between the spacers 103 and 103 disposed opposite to each other in the thickness direction of the prismatic secondary battery 100 is greater than the distance D1 between the first contact parts 120 and 120. The distance D2 between 121 is widened.

  Therefore, as shown in FIG. 6, when the prismatic secondary battery 100 is held between the intermediate cell holders 92 and 92 or between the end cell holder 93 and the intermediate cell holder 92 and a load is applied in the thickness direction, the battery can The width direction end region R1 which is less likely to expand than the one width direction intermediate region R2 and has a small thickness is reliably held between the first contact portions 120, 120 facing each other with a relatively narrow distance D1. Thereby, the square secondary battery 100 is held in a state of being reliably positioned in the cell holder 91 shown in FIG. 2, and is reliably prevented from being moved or displaced due to, for example, vibration in the vehicle.

  The intermediate region R2 in the width direction of the wide side surface 1b of the battery can 1 has low rigidity, but the end region R1 in the width direction close to the narrow side surface 1c has relatively high rigidity. Therefore, in order to hold the battery so as to withstand a load such as vibration, the end region R1 in the width direction of the battery can 1 between the first contact portions 120 and 120 facing each other with a relatively small distance D1 as described above. It is effective to apply a relatively high load to the width direction end region R <b> 1 with little deformation of the battery can 1 by the first contact portion 120. Since there is a space in which no electrode group exists in the width direction end region R1 of the wide side surface 1b, no load is applied to the wound group even if a load is applied to the width direction end region R1.

  On the other hand, the intermediate region R2 in the width direction of the wide side surface 1b of the battery can 1 is compressed between the second contact portions 121 and 121 facing each other at a relatively wide distance D2 in the thickness direction of the rectangular secondary battery 100. Thereby, expansion | swelling of the wide side surface 1b of the battery can 1 can be suppressed effectively. In addition, the expansion of the battery can 1 does not deteriorate the battery characteristics of the rectangular secondary battery 100 so that the thickness in the width direction intermediate region R2 of the battery can 1 is thicker than the thickness of the width direction end region R1. Can be tolerated. Therefore, it is possible to apply an appropriate load while avoiding an excessive load being applied to the width direction intermediate region R2 of the wide side surface 1b and the electrode group in the battery can 1 by the spacer 103. It should be noted that by determining an appropriate load range for the wide side surface 1b of the battery can 1 by a charge / discharge experiment or the like of the square secondary battery 100 in advance, the second contact portions 121 and 121 are set to be within the load range. The interval D2 between them can be adjusted.

  Further, as described above, in the prismatic secondary battery module 200 according to the present embodiment, the spacers 103 and 103 disposed opposite to each other in the thickness direction of the prismatic secondary battery 100 are the first abutting portions facing each other. The surfaces of 120 and 120 and the second contact portions 121 and 121 are flat surfaces parallel to each other. Thereby, compared with the case where the 1st contact part 120,120 is made into the inclined surface which follows the expansion | swelling shape of the battery can 1, the wide side surface 1b of the battery can 1 by the 1st contact part 120,120. A large load is applied to the vicinity of the boundary with the width direction end region R1, particularly the width direction intermediate region R2, and the prismatic secondary battery 100 can be more securely held by the cell holder 91. Moreover, it becomes possible to make the shape of the center part of the wide side surface 1b of the battery can 1 expanded in a convex shape closer to a flatter shape.

  As described above, according to the prismatic secondary battery module 200 that is the assembled battery of the present embodiment, the prismatic secondary battery 100 is reliably held to improve positioning accuracy, and the battery can constituting the battery container 2 1 expansion can be suppressed.

[Embodiment 2]
Next, Embodiment 2 of the assembled battery of the present invention will be described with reference to FIGS. FIG. 7 is a side view of the prismatic secondary battery 100 showing the positional relationship between the first contact portions 120 a, 120 c, 120 c, 120 b of the four spacers 103 of the present embodiment and the wide side surface 1 b of the battery can 1. .

  The prismatic secondary battery module 201 which is an assembled battery according to the present embodiment includes at least one of the plurality of spacers 103 adjacent in the height direction (Z direction) of the wide side surface 1b of the battery can 1 of the prismatic secondary battery 100. As described above, the length of the first contact portion 120c along the width direction (Y direction) of the wide side surface 1b is different from the length of the first contact portions 120a and 120b of the other spacers 103 in the same direction. This is different from the prismatic secondary battery module 200 of the first embodiment. About the other point, since the square secondary battery module 201 of this embodiment and the square secondary battery module 200 of Embodiment 1 are the same, the same code | symbol is attached | subjected to the same part and description is abbreviate | omitted.

  As shown in FIG. 7, in the present embodiment, the plurality of spacers 103 adjacent in the height direction of the wide side surface 1b of the battery can 1 include first contact portions 120a, 120b, The lengths La, Lb, and Lc of 120c are gradually increased from the center in the height direction of the wide side surface 1b toward the end.

  In the first embodiment, the first contact portion 120 that contacts the width direction end region R1 of the wide side surface 1b of the prismatic secondary battery 100 is 4 in the height direction (vertical direction) of the wide side surface 1b of the battery can 1. In the book, the length along the width direction of the wide side surface 1b was the same. However, in this embodiment, the lengths La and Lb of the contact portions 120a and 120b of the uppermost spacer 103 and the lowermost spacer 103 are equal to the length of the contact portion 120c of the spacer 103 located in the middle in the vertical direction. It is longer than Lc. That is, the first contact portion 120a of the intermediate spacer 103 positioned on the uppermost side in the height direction of the wide side surface 1b and the first contact portion 120b of the intermediate spacer 103 positioned on the lowermost side are in the height direction. Are in contact with the wide side surface 1b of the battery can 1 longer than the first contact portions 120c and 120c of the two intermediate spacers 103 and 103 located in the middle of the two.

  As described above, the battery can 1 constituting the battery case 2 of the square secondary battery 100 expands so that the thickness of the central portion of the wide side surface 1b is the largest. Correspondingly, in the rectangular secondary battery module 201 of the present embodiment, the length Lc of the first contact portion 120c of the spacer 103 located in the middle in the height direction of the wide side surface 1b of the battery can 1 is It is shorter than the lengths La and Lb of the first contact portions 120a and 120b of the upper and lower intermediate spacers 103. As a result, expansion at the intermediate portion in the height direction of the wide side surface 1b can be further allowed, the load applied to the electrode group in the battery can 1 can be further reduced, and the first contact between the upper and lower spacers 103 can be reduced. The width direction end region R1 of the battery can 1 can be reliably held by the contact portions 120a and 120b.

  As described above, according to the prismatic secondary battery module 201 that is the assembled battery according to the present embodiment, the prismatic secondary battery 100 is securely held to improve positioning accuracy, and the battery can constituting the battery container 2 1 expansion can be suppressed.

[Embodiment 3]
In the prismatic secondary battery modules 200 and 201 of the first and second embodiments described above, a space exists between the plurality of spacers 103 in order to flow a cooling medium such as cooling air. However, a plurality of intermediate spacers 103 may be integrally connected in the height direction of the wide side surface 1 b of the battery can 1 without providing a space between the plurality of intermediate spacers 103. An embodiment of such a prismatic secondary battery module is shown in FIG.

  FIG. 8 is a view corresponding to FIG. 7 of the second embodiment, showing the relationship between the first contact portion 120d of the intermediate spacer 103P of the prismatic secondary battery module of the present embodiment and the wide side surface 1b of the battery can 1. It is.

  As shown in the figure, the spacer 103P is provided continuously from the upper end to the lower end of the wide side surface 1b of the battery can 1, and is located at the intermediate portion in the height direction excluding the height direction end of the wide side surface 1b of the battery can 1. Mostly, it is provided in a plate shape facing the wide side surface 1b. The upper end and the lower end of the intermediate spacer 103P in the height direction of the wide side surface 1b may be connected to the upper end spacer 102 and the lower end spacer 101.

  As described above, the first contact portion 120d of the spacer 103P is continuous above and below in the height direction of the wide side surface 1b, so that the area that holds the battery can 1 more than the spacer 103 of the first and second embodiments. Becomes larger. Therefore, the prismatic secondary battery 100 can be reliably positioned by holding the prismatic secondary battery 100 more reliably and withstanding a higher load such as vibration.

  The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

2 Battery container 1b Wide side surface 100 Square secondary battery 103 Intermediate spacer (spacer)
103P Spacer (spacer)
120 1st contact part 121 2nd contact part 200 Rectangular secondary battery module (assembled battery)
D1 Interval between first contact portions D2 Intervals between second contact portions La, Lb, Lc Length of first contact portion R1 Width direction end region R2 Width direction intermediate region T1 First contact Contact portion thickness T2 Second contact portion thickness X Square secondary battery thickness direction Y Wide side width direction Z Wide side surface height direction

Claims (6)

A battery pack in which a plurality of rectangular secondary batteries in which an electrode group in which positive and negative electrodes are wound is accommodated and arranged in a flat box type battery container are stacked with a spacer interposed in the thickness direction,
The spacer includes a first contact portion that contacts a width direction end region of the wide side surface of the battery container, and a second contact portion that contacts a width direction intermediate region of the wide side surface,
The interval between the spacers arranged opposite to each other in the thickness direction of the prismatic secondary battery is wider between the second contact portions than the interval between the first contact portions. Assembled battery.   2. The set according to claim 1, wherein the spacer has a thickness of the first contact portion that is greater than a thickness of the second contact portion in a thickness direction of the rectangular secondary battery. battery. A plurality of the spacers are provided in the height direction of the wide side surface,
3. The assembled battery according to claim 2, wherein at least one of the plurality of spacers is different from the other spacers in length of the first contact portion along the width direction of the wide side surface.   In the plurality of spacers adjacent to each other in the height direction of the wide side surface, the length of the first abutting portion along the width direction of the wide side surface is changed from the center portion in the height direction of the wide side surface to the end portion. The assembled battery according to claim 3, wherein the battery pack gradually becomes longer toward the battery pack.   The assembled battery according to claim 2, wherein the spacer is provided continuously from the upper end to the lower end of the wide side surface.   The spacers arranged opposite to each other in the thickness direction of the prismatic secondary battery are such that the surfaces of the first contact portion and the second contact portion facing each other are flat surfaces parallel to each other. The assembled battery according to any one of claims 1 to 5, characterized in that:

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