JP2010040295A - Battery device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery device capable of increasing the force of binding stacked battery cells. <P>SOLUTION: A battery pack 1 includes a stack 30 having the battery cells stacked in the direction of DR1, a pair of end plates 20 arranged at both ends of the stack 30 in the stacking direction, and binding bands 10 for fastening the end plates 20 to each other. The binding bands 10 each have a band plate portion extending in the direction of the DR1, and bent portions bent at both ends of the band plate portion perpendicularly to the direction of the DR1. On opposite faces 23 of the end plates 20 opposite to the stack 30, the bent portions are fixed to the end plates 20. When the battery cells thrust the end plates 20, the binding bands 10 are deformed. The deformed binding bands 10 protrudingly deflect the end plates 20 to the sides of the opposite faces 23 to suppress the deformation of the battery cells. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power storage device, and more particularly, to a power storage device configured by stacking power storage cells in one stacking direction.

  The power storage device includes a battery pack including a single battery cell, a battery pack including a stacked body in which a plurality of battery cells are stacked, and a plurality of battery modules in which a plurality of battery cells are integrally fixed. There is a battery pack. A battery pack in which battery modules including a plurality of battery cells are stacked can extract a large current or a high voltage.

  In recent years, an electric vehicle using an electric motor as a drive source and a so-called hybrid electric vehicle combining an electric motor and another drive source have been put into practical use. A battery pack provided with a battery module is mounted on such an automobile, for example. As the battery cell for storing the battery, for example, a secondary battery that can be repeatedly charged and discharged, such as a nickel-cadmium battery, a nickel-hydrogen battery, or a lithium ion battery, is used.

  When the battery pack is used, the battery cell expands due to an increase in internal pressure. In a battery module in which a plurality of battery cells are integrated, it is necessary to prevent the battery module from being damaged at the boundary between the battery cells due to the expansion of the battery cells, and the battery performance from being deteriorated. Since it is necessary to suppress the deformation of the battery cell in order to prevent the deterioration of the battery performance, in a battery pack including a plurality of battery modules, a plurality of battery modules are integrated using a restraining member. For example, a plurality of battery modules are stacked to form a stacked body, and end plates arranged on both sides of the stacked body are fixed with, for example, round bars as restraining members, and the battery modules are sandwiched between the end plates to be integrated. It has become.

  In such a battery pack, when the battery cell is expanded, a large force is applied to the joint portion between the round bar and the end plate in the stacking direction of the battery modules. Alternatively, a large force is applied to the round bar itself. Therefore, in order to improve the strength of the round bar, it is necessary to make the diameter of the round bar considerably large. As a result, the round bar becomes thick and the height of the battery pack is high.

In order to avoid this problem, conventionally, a battery pack in which a plurality of battery modules are integrated using a plate-like restraining member has been proposed (see, for example, Patent Document 1 or Patent Document 2).
JP 2001-68081 A JP 2008-16259 A

  In the battery pack using the plate-like restraining member proposed in Patent Documents 1 and 2, the battery pack is restrained by the tensile stress generated in the restraining member. Therefore, in order to increase the restraining force on the battery module, it is necessary to increase the rigidity of the restraining member itself as in the case where the round bar is used as the restraining member. In order to increase the rigidity of the restraining member, it is conceivable to increase the thickness and width of the plate-like restraining member. However, from the viewpoint of weight reduction of the battery pack and the manufacturing cost, such thickness or width is large. A restraining member is undesirable.

  Therefore, a main object of the present invention is to provide a power storage device that can increase the binding force of stacked battery cells.

  A power storage device according to the present invention includes a stacked body in which power storage cells are stacked in one stacking direction, a pair of end plates disposed at both ends in the stacking direction of the stacked body, and a restraining member that fastens the end plates. Prepare. The restraining member has a strip-shaped plate portion extending in the stacking direction and bent portions bent at right angles to the stacking direction at both ends of the strip-shaped plate portion. The bent portion is fixed to the end plate on the facing surface of the end plate facing the laminate. When the electricity storage cell presses the end plate, the restraining member is deformed, and the deformed restraining member deflects the end plate convexly toward the facing surface, thereby suppressing the deformation of the electricity storage cell.

  Preferably, in the power storage device, the belt-like plate portion is disposed in parallel to the side surface of the stacked body. The bent portion is bent in a direction away from the laminate with respect to the belt-like plate portion.

  Preferably, an even number of restraining members are provided at positions facing one side surface of the laminate. The strip-shaped plate portion is disposed perpendicular to one side surface. The bent portion is bent with respect to the belt-like plate portion in a direction away from a center line that extends in the stacking direction and bisects one side surface.

  Preferably, an even number of restraining members are provided at positions facing one side surface of the laminate. The strip-shaped plate portion includes a parallel surface provided parallel to one side surface and a vertical surface provided perpendicular to the one side surface, and a cross-sectional shape L-shaped in which the parallel surface and the vertical surface are combined. Is formed. The bent portion is bent in a direction away from the laminate with respect to the parallel plane, and is bent in a direction away from the center line extending in the stacking direction and dividing one side surface into two with respect to the vertical plane. ing.

  According to the power storage device of the present invention, when the power storage cell presses the end plate due to an increase in the internal pressure of the power storage cell, the pair of end plates move away from each other. Along with the displacement of the end plate, the bending portion of the restraining member fixed to the end plate is deformed. At this time, the end plate receives a bending moment due to the load acting on the end plate from the bending portion, and the end plate bends convexly toward the facing surface facing the laminate. Due to the bending of the end plate, a force in a direction to suppress the deformation of the storage cell is applied to the stacked body from the end plate. Therefore, since the deformation amount of the power storage cell is suppressed, it is possible to prevent the stacked body from being damaged, and to prevent the performance of the power storage device from deteriorating.

  Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  In the embodiments described below, each component is not necessarily essential for the present invention unless otherwise specified. In the following embodiments, when referring to the number, amount, etc., unless otherwise specified, the above number is an example, and the scope of the present invention is not necessarily limited to the number, amount, etc.

(Embodiment 1)
FIG. 1 is a perspective view illustrating a configuration of the power storage device of the first embodiment. FIG. 2 is a perspective view illustrating the shape of the restraining member. FIG. 3 is a diagram of the power storage device shown in FIG. 1 as viewed from the direction of arrow III. FIG. 4 is a diagram of the power storage device shown in FIG. 1 as viewed from the direction of arrow IV. With reference to FIGS. 1-4, the electrical storage apparatus of Embodiment 1 of this invention is demonstrated.

  The battery pack 1 as the power storage device of the first embodiment is mounted on a hybrid vehicle using an internal combustion engine such as a gasoline engine or a diesel engine and a chargeable / dischargeable secondary battery as power sources. The battery pack 1 is arranged such that, for example, in the space provided in the lower body of the rear seat of the vehicle, the longitudinal direction thereof is the vehicle width direction. The battery pack is housed inside a battery case, which is a container for storing battery electrodes and electrolyte. The battery case is preferably made of a resin from the viewpoint of chemical resistance and insulation, but may be made of metal.

  The battery pack 1 includes a stacked body 30 in which a plurality of battery modules 31 are integrally stacked in the thickness direction. The plurality of battery modules 31 are stacked in the DR1 direction, which is the thickness direction of the battery module 31, as one stacking direction. A positioning portion is provided on a combination surface where the battery modules 31 stacked in the thickness direction are combined with other adjacent battery modules 31. A pair of battery modules 31 abutted against each other by this positioning portion are positioned with respect to each other in the height direction and the width direction, and the arrangement posture of the battery modules 31 is aligned.

  The battery module 31 of the first embodiment is a rectangular battery module that is integrated in a state in which battery cells as a plurality of storage cells are arranged to form a flat plate shape. The stacked body 30 includes a plurality of battery cells stacked in the DR1 direction. The battery cell which comprises the battery module 31 contains a lithium ion battery. The battery cell is made of, for example, plastic and is formed in a flat rectangular parallelepiped box shape, and accommodates an electrolyte and an electrode plate constituting the secondary battery, respectively. The inside of the battery module 31 is separated by an internal partition, and the battery cells are accommodated in the separated rooms.

  The plurality of battery modules 31 are electrically connected to each other by a bus bar (not shown). All the battery cells included in the battery pack 1 are electrically connected in series, and a high voltage output is possible. Each battery module 31 is clamped by a battery holder (not shown) as a frame member that electrically insulates the battery modules 31 adjacent in the DR1 direction. The battery holder may be formed from a resin material that is an insulating material such as polypropylene or a polymer of polypropylene, or may be formed from a metal whose surface is coated with a resin that is an insulating material.

  The battery pack 1 includes a pair of end plates 20 disposed at both ends in the DR1 direction, which is the stacking direction of the stacked body 30 of the battery module 31. The end plate 20 of Embodiment 1 has a rectangular plate-like portion similar to the shape of the battery module 31 so that the facing surface 23 facing the battery module 31 is in close contact with the entire surface of the battery module 31. The end plate 20 is disposed so as to sandwich the stacked body 30 in which the battery modules 31 are stacked from both sides in the DR1 direction, which is the stacking direction. The end plate 20 is disposed at both ends of the stacked body 30.

  On the upper edge 21a of the rectangular plate-like portion of the end plate 20, a pair of projecting portions 22a projecting upward in a semicircular shape is provided at an appropriate interval. In addition, a pair of projecting portions 22b projecting downward in a semicircular shape is provided on the lower edge 21b of the rectangular plate-shaped portion of the end plate 20 at an appropriate interval. The end plate 20 is made of an arbitrary material such as a metal or a resin material.

  The battery pack 1 includes a restraining band 10 as a restraining member. The restraint band 10 is formed in a plate shape. The restraint band 10 is formed to have a longitudinal direction. The restraint band 10 is disposed so that the longitudinal direction extends in the DR1 direction, which is the stacking direction of the battery modules 31. The pair of end plates 20 is supported by the longitudinal restraint bands 10 arranged on both sides of the battery module 31 so that the battery module 31 between them is pressed in the DR1 direction, that is, a preload is applied. Are interconnected. The restraining band 10 is disposed so as to fasten the pair of end plates 20 to each other.

  A pair of protrusions 22 a formed on the upper edge 21 a of each end plate 20 disposed at both ends of the battery pack 1 is a side surface 32 that is one of the side surfaces of the stacked body 30 abutted against the end plate 20. Each projecting upward. Further, the pair of protruding portions 22 b formed on the lower edge 21 b of each end plate 20 protrudes downward from the side surface 35 that is one of the side surfaces of the stacked body 30. Here, the side surface of the stacked body 30 refers to the surface of the stacked body 30 formed by arranging the side surfaces of the plate-shaped battery modules 31 side by side. In the case of the rectangular parallelepiped laminated body 30 shown in FIGS. 1, 3, and 4, the side surfaces of the laminated body 30 are the four surfaces of the laminated body 30 excluding the two surfaces facing the end plate 20, 33, 34, and 35 are shown.

  Between the projecting portions 22 a and 22 b facing each other in each end plate 20, a restraining member, that is, a restraining band 10 that is parallel to the stacking direction of the battery modules 31 is spanned. The restraint band 10 is fixed to the end plate 20 by bolts 28 and nuts 29 as fastening members. The restraint band 10 is disposed so as to restrain the battery module 31 in the stacking direction. The plurality of battery modules 31 are integrally held by the restraining band 10 to form the battery pack 1.

  As shown in FIG. 2 in an enlarged manner, the restraining band 10 includes a flat belt-like plate portion 11 extending in the DR1 direction, and a bent portion 12 bent in the DR2 direction orthogonal to the DR1 direction at both ends of the belt-like plate portion 11. And have. The restraining band 10 is bent at both ends to form a bent portion 12. The bent portion 12 is bent at a right angle to the DR1 direction. A hole 13 is formed in the bent portion 12. A bolt 28 is installed through the hole 13 and fastened to the end plate 20 using a nut 29, whereby the restraining band 10 is fixed to the end plate 20. The bending portions 12 of the restraining band 10 including bending are fixed to the pair of end plates 20 on the respective facing surfaces 23.

  Bolts 28 are respectively inserted into the holes 13 formed in the bent portions 12 formed at both ends of the restraining band 10 and the through holes formed in the projecting portions 22a and 22b of the end plates 20, respectively. The nuts 29 are screwed into the end portions of the nuts. Thereby, a pair of end plate 20 is connected by each restraint band 10, and the battery module 31 between these pair of end plates 20 is press-contacted mutually by the predetermined preload.

  The pair of end plates 20 are moved in a direction approaching each other when the nuts 29 are tightened at the bent portions 12 formed at the respective end portions of the respective restraining bands 10, and are stacked. 31 is pressed in the thickness direction so as to be in close contact with each other. The plurality of battery modules 31 are integrally fixed in a state where pressure in the thickness direction is applied to each other.

  Hereinafter, the behavior of the restraining band 10 when the internal pressure of the battery cell increases will be described. FIG. 5 is a schematic cross-sectional view exaggeratingly showing a state in which the restraint band is fixed between the pair of end plates. As described with reference to FIGS. 1 to 4, the bending portion 12 of the restraining band 10 includes the bolt 28 and the nut 29 on the facing surface 23 where the pair of end plates 20 faces the stacked body 30 of the battery module 31. Used to be fixed to the end plate 20. In FIG. 5 and FIGS. 6 to 11 described later, the stacked body 30 of the battery module 31 is not shown for simplification.

  FIG. 6 is a schematic diagram showing the pressing force applied to the end plate when the internal pressure of the battery cell increases. In any battery cell included in any battery module 31 in the laminate 30, the internal pressure of the battery cell increases due to, for example, generation of hydrogen gas inside the battery cell, and the battery cell particularly in the thickness direction. There is a risk of expansion in (DR1 direction).

  When any one of the battery cells expands in the DR1 direction, the battery cell presses the end plate 20, and a pressing force F1 is applied from the stacked body 30 toward the end plate 20, as indicated by an arrow in FIG. By the action of the pressing force F1, the pair of end plates 20 move away from each other along the DR1 direction. The end plate 20 moves outward by the pressing force F <b> 1 that the battery cell presses the end plate 20. That is, the end plate 20 receives a load applied from the battery cell when the internal pressure of the battery cell increases, and is displaced in a direction from the facing surface 23 facing the battery cell toward the back surface 24 opposite to the facing surface 23. .

  At this time, when the pressing force F1 is applied from the battery cell, the end plate 20 is bent, but the rigidity of the end plate 20 is sufficiently high so that the amount of deflection is kept small relative to the displacement amount of the end plate 20. It is done. When the battery cell presses the end plate 20, the amount of deformation generated in the end plate 20 is small, and the end plate 20 moves in the DR1 direction while maintaining the shape before the load is applied.

  Since the pair of end plates 20 move away from each other and the interval between the end plates 20 increases, the restraining band 10 is pulled and deformed. At this time, both of the two bent portions 12 at both ends of the restraint band 10 are fixed to the end plate 20 on the facing surfaces 23 which are inner surfaces facing each other of the pair of end plates 20. The bending portion 12 of the restraining band 10 fixed to the end plate 20 moves so as to follow the end plate 20 and elastically deforms as shown in FIG.

  FIG. 7 is an enlarged schematic view showing the vicinity of the bent portion of the restraining band when the internal pressure of the battery cell increases. As shown in FIG. 7, the bending portion 12 includes a fastening portion 12a that is a portion fastened to the bolt 28 and fixed to the end plate 20, and an outer end portion 12b that is closer to the end portion of the restraining band 10 than the fastening portion 12a. The connecting portion 12c is closer to the belt-like plate portion 11 than the fastening portion 12a.

  When the pressing force F1 is applied from the battery cell to the end plate 20, the restraining band 10 is elastically deformed as shown in FIG. In the fastening portion 12 a, the bending portion 12 is fixed to the end plate 20, and the bending portion 12 is bent and deformed so that the connecting portion 12 c is separated from the facing surface 23 of the end plate 20 by the displacement of the end plate 20. At this time, a repulsive force F2 is applied from the outer end 12b toward the end plate 20, as indicated by an arrow in FIG.

  Due to the action of the repulsive force, the end plate 20 receives a bending moment M in a direction indicated by a curved arrow in FIG. Due to the action of the bending moment M, the end plate 20 is bent and deformed so that the opposing surface 23 side has a convex shape and the back surface 24 side has a concave shape. Since the end plate 20 is deformed so that the opposing surface 23 protrudes, and the distance between the pair of end plates 20 is reduced, the stacked body 30 of the battery modules 31 from the end plate 20 is indicated by an arrow in FIG. Restraint force F3 acts. FIG. 8 is a schematic diagram showing a state where the end plate is bent and deformed. Since the restraining force F3 acts on the laminated body 30 from the end plate 20, a force opposite to the pressing force F1 that the battery cell shown in FIG. 6 presses the end plate 20 is applied from the end plate 20 to the battery cell. become. That is, since the restraining force F3 acts in the direction that cancels the pressing force F1, deformation of the battery cells included in the battery module 31 is suppressed.

  Here, the thickness and the width of the restraint band 10 are adjusted so that the restraint band 10 has sufficient strength to be elastically deformed when the pressing force F1 is applied and to apply the repulsive force F2 to the end plate 20. The restraint band 10 may be formed of any material as long as it is an elastic material that can be elastically deformed to generate the repulsive force F2 when the pressing force F1 is applied to the end plate 20, for example, It can be formed of a metal plate.

  As described above, the restraint band 10 according to the first embodiment includes the belt-like plate portion 11 extending in the DR1 direction that is the lamination direction of the laminated body 30 of the battery module 31, and the both ends of the belt-like plate portion 11 orthogonal to the DR1 direction. The bent portion 12 is bent in the DR2 direction. The bent portion 12 is fixed to the end plate 20 on the facing surface 23 where the end plate 20 faces the stacked body 30. When the battery cell included in the battery module 31 presses the end plate 20, the restraint band 10 is deformed, and the deformed restraint band 10 bends the end plate 20 toward the opposing surface 23, thereby deforming the battery cell. Suppress.

  In this way, when the battery cell applies the pressing force F1 to the end plate 20 due to an increase in the internal pressure of the battery cell, the pair of end plates 20 move away from each other. As the end plate 20 is displaced, the bending portion 12 of the restraining band 10 fixed to the end plate 20 is deformed. At this time, the end plate 20 receives a bending moment M by the repulsive force F <b> 2 acting on the end plate 20 from the bending portion 12, and the end plate 20 is bent convexly toward the facing surface 23 facing the laminate 30.

  Due to the bending of the end plate 20, a restraining force F <b> 3 in a direction that suppresses deformation of the battery cell is applied to the stacked body 30 from the end plate 20. When the internal pressure of the battery cell rises, a restraining force F3 in a direction that restricts the swelling of the battery cell is applied from the end plate 20 to the stacked body 30 of the battery module 31. Thereby, even if the internal pressure of any battery cell included in any battery module 31 increases, the expansion of the battery cell is suppressed. Therefore, since the deformation amount of the battery cell is suppressed and the battery cell can be restrained, the battery module 31 is prevented from being damaged at the boundary between the battery cells and the stacked body 30 is prevented from being damaged. Can be avoided.

  In the conventional battery pack structure in which a round bar or a plate-like member is used as the restraining member, the restraining force of the battery pack is increased by increasing the rigidity of the restraining member itself. On the other hand, in the battery pack 1 of the present embodiment, in addition to the rigidity of the restraint band 10 itself, the repulsive force F2 that acts on the end plate 20 when the restraint band 10 is elastically deformed is used as the laminate 30 of the battery modules 31. It can be used by converting into a restraining force F3. Accordingly, even when the plate thickness or width of the restraining band 10 is reduced to reduce the rigidity of the restraining band 10 itself as compared with the conventional restraining member, the same restraining force can be obtained. Weight reduction and manufacturing cost reduction can be achieved. Or when it is set as the restraint band 10 which has plate | board thickness and width | variety equivalent to the conventional restraint member, the restraint force of the battery pack 1 can be increased compared with the conventional restraint member.

  Even if the restraint band 10 has the strip-shaped plate portion 11 and the bent portion 12 bent at a right angle with respect to the strip-shaped plate portion 11, the bent portion 12 may be attached to the end plate 20 depending on the bending direction of the bent portion 12. The repulsive force F2 acting on the force cannot be converted into the restraining force F3. That is, when the repulsive force F2 is applied to the end plate 20 at a position closer to the center portion of the facing surface 23 of the end plate 20 with respect to the fastening portion 12a where the bent portion 12 is fixed to the end plate 20, The end plate 20 receives a bending moment opposite to the bending moment M shown in FIG. The end plate 20 that has received a bending moment opposite to the bending moment M bends in the opposite direction to the bending shape shown in FIG. 8, and in this case, the binding force F3 is not applied to the stacked body 30 of the battery module 31. On the contrary, the binding force of is reduced.

  Therefore, in the restraint band 10 according to the first embodiment, the belt-like plate portion 11 is arranged in parallel to the side surface 32 of the laminated body 30, and the bent portion 12 is separated from the laminated body 30 with respect to the belt-like plate portion 11. It is bent in the direction. In this way, the repulsive force F2 can be applied to the end plate 20 at a position farther from the center portion of the facing surface 23 than the fastening portion 12a, so that the restraining force F3 is reliably applied to the stacked body 30. be able to. In addition, the belt-like plate portion 11 can be disposed close to the laminated body 30, which is desirable because the overall shape of the battery pack 1 can be reduced in size.

  In the battery pack 1, since the battery remaining capacity of the battery cells included in each battery module 31 is not constant and varies, the internal pressure of all the battery cells does not rise uniformly and expand. Therefore, the protrusions 22a and 22b formed on the end plate 20 are formed with the mutual distance in the width direction of the end plate 20 orthogonal to the DR1 direction as much as possible, and the protrusions 22a and 22b are formed in the end plate 20. The upper edge 21a or the lower edge 21b is preferably formed in the vicinity of the end.

  Even if any one battery cell expands by forming the protrusions 22a and 22b at a large interval, the end plate 20 restrained by the restraining band 10 expands the battery cell. Is surely suppressed. For this reason, it is possible to reliably prevent the battery performance from being deteriorated and the battery case from being destroyed due to the expansion amount of the battery cell exceeding the allowable value.

(Embodiment 2)
FIG. 9 is a perspective view showing a schematic configuration of the power storage device of the second embodiment. FIG. 10 is a schematic cross-sectional view exaggeratingly showing a state in which the restraint band of the second embodiment is fixed between a pair of end plates. As shown in FIGS. 9 and 10, the second embodiment differs from the first embodiment in the arrangement of the band-shaped plate portion 11 of the restraining band 10.

  Specifically, the restraint band 10 is disposed at a position facing the side surfaces 32 and 35 shown in FIGS. 1 and 4, which is one side surface of the stacked body 30 of the battery module 31. Two restraining bands 10 are provided at a position facing the side surface 32, and two restraining bands 10 are provided at a position facing the side surface 35. The strip-shaped plate portion 11 is disposed perpendicular to the side surfaces 32 and 35 of the stacked body 30. The strip-shaped plate portion 11 extends in the DR1 direction, which is the stacking direction of the stacked body 30. The bent portion 12 is bent at right angles to the DR1 direction so as to be along the DR3 direction orthogonal to the DR1 direction.

  A virtual center line CL that bisects the side surfaces 32 and 35 of the stacked body 30 is indicated by a one-dot chain line in FIG. The center line CL is a straight line extending in the DR1 direction that bisects the surface area of the side surface 32 or the side surface 35. As shown in FIGS. 9 and 10, the bent portion 12 is bent with respect to the strip-shaped plate portion 11 in a direction away from the center line CL.

  FIG. 11 is a schematic cross-sectional view showing deformation of the restraining band when the internal pressure of the battery cell of Embodiment 2 increases. As shown in FIG. 11, as in the first embodiment, when the internal pressure of the battery cell rises and the pressing force F1 is applied to the end plate 20, a repulsive force F2 is generated along with the deformation of the restraining band 10. The end plate 20 receives a bending moment M due to the action of the repulsive force F <b> 2, and bends convexly toward the facing surface 23 facing the laminate 30. Due to this bending, a restraining force in the direction opposite to the pressing force F <b> 1 acts on the stacked body 30 from the end plate 20, and a force in a direction that restricts the swelling of the battery cells is applied to the stacked body 30. Therefore, since the deformation amount of the battery cell is suppressed and the battery cell can be restrained, the battery module 31 can be prevented from being damaged at the boundary between the battery cells, and the battery performance can be prevented from being lowered. .

  When the bending direction of the bending portion 12 with respect to the belt-like plate portion 11 is aligned in one direction, even if the repulsive force F2 of the restraining band 10 acts on the end plate 20, the bending moment in the direction shown in FIG. M may not work. That is, if the position where the outer end portion 12b applies a repulsive force to the end plate 20 is not a position farther from the center portion of the facing surface 23 with respect to the fastening portion 12a, the bending moment M shown in FIG. 11 is not generated. The end plate 20 may bend in a direction different from the direction in which the binding force is applied to the stacked body 30.

  Therefore, in the second embodiment, the bent portion 12 is formed in a direction away from the center line CL with respect to the belt-like plate portion 11 arranged perpendicular to the side surfaces 32 and 35 of the stacked body 30. In this way, the repulsive force F2 can be applied to the end plate 20 at a position farther from the center portion of the facing surface 23 than the fastening portion 12a, so that the bending moment M acts on the end plate 20 with certainty. A restraining force F3 can be applied to the stacked body 30. In addition, by providing an even number of restraining bands 10 per side surface of the laminate 30, a uniform bending moment M can be applied to the end plate 20.

(Embodiment 3)
FIG. 12 is a perspective view showing a schematic configuration of the power storage device of the third embodiment. As shown in FIG. 12, the restraint band 10 of Embodiment 3 is arranged at a position facing one of the side surfaces 32 and 35 shown in FIGS. 1 and 4, which is one side surface of the stacked body 30 of the battery module 31. Yes. Two restraining bands 10 are provided at a position facing the side surface 32, and two restraining bands 10 are provided at a position facing the side surface 35.

  The strip-shaped plate portion 11 extends in the DR1 direction, which is the stacking direction of the stacked body 30. The strip-shaped plate portion 11 includes a parallel surface 11 a provided parallel to the side surfaces 32 and 35 of the stacked body 30 and a vertical surface 11 b provided perpendicular to the side surfaces 32 and 35 of the stacked body 30. The band-shaped plate portion 11 is formed by combining a parallel surface 11a and a vertical surface 11b so that a cross-sectional shape perpendicular to the DR1 direction that is the stacking direction of the stacked body 30 is an L-shape.

  The bent portion 12 is bent at right angles to the extending direction of the strip-shaped plate portion 11 at both ends of the strip-shaped plate portion 11. The bent portion 12 is fixed to the end plate 20 on the facing surface 23 of the end plate 20. The bent portion 12 is bent in a direction away from the stacked body 30 with respect to the parallel surface 11a. The bent portion 12 is bent in a direction away from the center line CL described in the second embodiment with respect to the vertical surface 11b.

  Also in the battery pack having the configuration of the third embodiment described above, when the internal pressure of the battery cell rises and an outward pressing force is applied to the end plate 20, the repulsive force F2 is accompanied by the deformation of the restraining band 10. Is generated, and the end plate 20 receives a bending moment M by the action of the repulsive force F <b> 2, and bends in a convex manner toward the facing surface 23 facing the laminate 30. Due to this bending, a restraining force in the direction opposite to the pressing force F <b> 1 acts on the stacked body 30 from the end plate 20, and a force in a direction that restricts the swelling of the battery cells is applied to the stacked body 30. Therefore, since the deformation amount of the battery cell is suppressed and the battery cell can be restrained, the battery module 31 can be prevented from being damaged at the boundary between the battery cells, and the battery performance can be prevented from being lowered. .

  In the description of the first to third embodiments, the battery cell is a lithium ion battery, but is not limited to this form, and the present invention can be applied to a battery module including any battery cell. For example, the battery cell may include a nickel-cadmium battery or a nickel-hydrogen battery. Further, the power storage device is not limited to this form, and may have a function of storing electricity. For example, the power storage device may include a capacitor.

  Further, the present invention is not limited to a rectangular flat battery module, and the present invention can be applied to a battery pack including a battery module having an arbitrary shape. For example, the present invention may be applied to a battery pack in which a cylindrical stacked body in which disk-shaped battery modules are stacked is sandwiched between a pair of end plates.

  In the above description, the hybrid vehicle that drives the internal combustion engine at the fuel efficiency optimum operating point has been described as an example. However, the present invention is not limited to this mode, and the fuel cell uses a fuel cell and a secondary battery as driving sources. The power storage device of the present invention can also be applied to a hybrid vehicle (FCHV: Fuel Cell Hybrid Vehicle) or an electric vehicle (EV: Electric Vehicle). Furthermore, the present invention is not limited to a power storage device mounted on an automobile, and can be applied to a power storage device in which arbitrary power storage modules are stacked.

  Although the embodiment of the present invention has been described as above, the embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a perspective view illustrating a configuration of a power storage device according to a first embodiment. It is a perspective view explaining the shape of a restraint member. It is the figure which looked at the electrical storage apparatus shown in FIG. 1 from the arrow III direction. It is the figure which looked at the electrical storage apparatus shown in FIG. 1 from the arrow IV direction. It is a cross-sectional schematic diagram which exaggerates and shows the state by which the restraint band is being fixed between a pair of end plates. It is a schematic diagram which shows the load added to an end plate when the internal pressure of a battery cell rises. It is a schematic diagram which expands and shows the bending part vicinity of a restraint band when the internal pressure of a battery cell rises. It is a schematic diagram which shows the state which the end plate bent and deformed. FIG. 6 is a perspective view illustrating a schematic configuration of a power storage device according to a second embodiment. It is a cross-sectional schematic diagram which exaggerates and shows the state where the restraint band of Embodiment 2 is being fixed between a pair of end plates. FIG. 6 is a schematic cross-sectional view showing deformation of a restraint band when the internal pressure of the battery cell of Embodiment 2 rises. FIG. 10 is a perspective view illustrating a schematic configuration of a power storage device according to a third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Battery pack, 10 Restraint band, 11 Strip | belt-shaped board part, 11a Parallel surface, 11b Vertical surface, 12 Bending part, 12a Fastening part, 12b Outer edge part, 12c Connection part, 13 Hole part, 20 End plate, 21a Upper edge, 21b Lower side edge, 22a, 22b Protruding part, 23 Opposing surface, 24 Back surface, 28 Bolt, 29 Nut, 30 Stack, 31 Battery module, 32, 33, 34, 35 Side surface.

Claims (4)

A stacked body in which storage cells are stacked in one stacking direction;
A pair of end plates disposed at both ends of the stack in the stacking direction;
A restraining member for fastening the end plates together,
The restraining member has a strip-shaped plate portion extending in the stacking direction, and bent portions bent at right angles to the stacking direction at both ends of the strip-shaped plate portion,
In the facing surface facing the laminate of the end plate, the bent portion is fixed to the end plate,
When the electricity storage cell presses the end plate, the restraint member is deformed, and the deformed restraint member suppresses deformation of the electricity storage cell by flexing the end plate convexly toward the facing surface. apparatus. The strip-shaped plate portion is disposed in parallel to the side surface of the laminate,
The power storage device according to claim 1, wherein the bent portion is bent in a direction away from the stacked body with respect to the strip-shaped plate portion. An even number of the restraining members are provided at positions facing one side surface of the laminate,
The belt-shaped plate portion is disposed perpendicular to the one side surface,
2. The power storage device according to claim 1, wherein the bent portion is bent in a direction away from a center line that extends in the stacking direction and bisects the one side surface with respect to the belt-shaped plate portion. An even number of the restraining members are provided at positions facing one side surface of the laminate,
The strip-shaped plate portion includes a parallel surface provided parallel to the one side surface and a vertical surface provided perpendicular to the one side surface, and the parallel surface and the vertical surface are combined. It is formed in a cross-sectional L shape,
The bent portion is bent in a direction away from the stacked body with respect to the parallel surface, and extends in the stacking direction with respect to the vertical surface, and from a center line that bisects the one side surface. The power storage device according to claim 1, wherein the power storage device is bent in a separating direction.

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