Energy storage unit

Abstract

The present invention can provide a power storage unit capable of inhibiting the expansion of a power storage element while allowing the structure to be simplified and made compact.　A power storage unit 10 comprises: a power storage pack 16 including a power storage element 12 and a holding case 14 for holding the power storage element 12; a housing 18 that accommodates the power storage pack 16; and a flat metal fitting 22 that is disposed in the housing 18 and is secured to the housing 18, the flat metal fitting 22 facing a mounting surface 20 of the power storage pack 16, which is made of metal, with the power storage pack 16 being interposed between the mounting surface and the flat metal fitting. The mounting surface 20 and the flat metal fitting 22 constitute a pressing member 60 that inhibits expansion of the power storage element 12.

Description

[Technical Field]

[0001] The present disclosure relates to an electricity storage unit. [Background technology]

[0002] Patent Document 1 discloses an electricity storage unit to be mounted on electrically powered automobiles such as electric vehicles and hybrid vehicles. In this electricity storage unit, an electricity storage pack, in which a plurality of electricity storage elements, such as lithium ion capacitors and lithium ion secondary batteries, are held in a synthetic resin holding case, is housed in a metal housing together with a printed circuit board and the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-100308 Summary of the Invention [Problem to be solved by the invention]

[0004] The energy storage unit of Patent Document 1 employs a pressure member attached to surround the holding case of the energy storage pack in order to suppress expansion of the energy storage element when gas is generated inside the energy storage element and internal pressure increases. However, since a specially configured pressure member is placed around the holding case in order to suppress expansion of the energy storage element, the structure becomes complicated and the energy storage unit becomes larger. Therefore, further improvements are needed.

[0005] Therefore, an object of the present invention is to provide an electricity storage unit that can suppress expansion of the electricity storage elements while enabling a simplified and compact structure. [Means for solving the problem]

[0006] The energy storage unit of the present disclosure includes an energy storage pack including an energy storage element and a holding case that holds the energy storage element; a control board connected to the energy storage pack; a housing that houses the energy storage pack and the control board; and a flat metal fitting that is arranged opposite a metal mounting surface of the housing for the energy storage pack with the energy storage pack interposed therebetween and is fixed to the housing, and the mounting surface and the flat metal fitting form a pressure member that suppresses expansion of the energy storage element. the holding case of the electricity storage pack has a pack-side elastic contact portion that elastically contacts the flat metal fitting, and the pack-side elastic contact portion is configured by an elastic tongue piece that is provided integrally with the holding case on the flat metal fitting side of the holding case. It is something that exists. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide an electricity storage unit that can suppress expansion of electricity storage elements while enabling a simplified and miniaturized structure. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an electricity storage unit according to the first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the electricity storage unit shown in FIG. [Figure 3] FIG. 3 is an enlarged perspective view of an electricity storage pack that constitutes the electricity storage unit shown in FIG. [Figure 4] 4 is a perspective view showing the overlapping portion of the flat metal fitting and the holding case that constitute the electricity storage unit shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a perspective view showing a flat metal fitting constituting the electricity storage unit according to the second embodiment, showing a state in which a separate spring member is attached. [Figure 7] FIG. 7 is a diagram showing the flat metal plate shown in FIG. 6 in a state before a separate spring member is attached. [Figure 8] FIG. 8 is a perspective view showing a main part of a holding case that constitutes the electricity storage unit according to the third embodiment. [Figure 9]FIG. 9 is a plan view showing the state in which the main part of the holding case and the flat metal fitting shown in FIG. 8 are superimposed on each other. [Figure 10] FIG. 10 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 11 is a perspective view showing a main part of a holding case that constitutes the electricity storage unit according to the fourth embodiment. [Figure 12] FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. [Figure 13] FIG. 13 is a perspective view showing a main part of a holding case that constitutes the electricity storage unit according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Description of Embodiments of the Present Disclosure> First, embodiments of the present disclosure will be listed and described. The power storage unit of the present disclosure includes: (1) An electric storage pack including an electric storage element and a holding case for holding the electric storage element; a control board connected to the electric storage pack; a housing for accommodating the electric storage pack and the control board; and a flat metal fitting disposed opposite a metal mounting surface of the housing for the electric storage pack with the electric storage pack interposed therebetween and fixed to the housing, wherein the mounting surface and the flat metal fitting constitute a pressure member for suppressing expansion of the electric storage element. The holding case of the electricity storage pack has a pack-side elastic contact portion that is in elastic contact with the flat metal plate. The pack-side elastic contact portion is configured by an elastic tongue piece that is provided integrally with the holding case on the flat metal fitting side of the holding case. It is something that exists.

[0010] According to this structure, a pressure member that suppresses expansion of the energy storage elements is configured by utilizing the mounting surface of the housing on which the energy storage pack is placed, through cooperation between the flat metal fitting that is disposed opposite the mounting surface via the energy storage pack and fixed to the housing, and the mounting surface. Therefore, unlike conventional structures, a dedicated pressure member is not required, and the pressure member can be configured using existing parts. Moreover, because it is sufficient to simply fix the flat metal fitting that is disposed opposite the mounting surface with the energy storage pack sandwiched between them to the housing, a complex structure for assembling a special pressure member to the holding case is also unnecessary. As a result, it is possible to provide an energy storage unit that can suppress expansion of the energy storage elements while achieving a simplified and compact structure.

[0011] Since the pressure member suppresses the expansion of the energy storage element, the flat metal fittings need only be configured to abut against the holding case of the energy storage pack at least when the energy storage element expands, but may also include a portion that abuts against the holding case before the energy storage element expands.

[0012] (2) The flat metal fitting preferably has a metal fitting-side elastic contact portion that elastically contacts the electricity storage pack. Elastic deformation of the metal fitting-side elastic contact portion provided on the flat metal fitting advantageously absorbs tolerances between the opposing surfaces of the mounting surface of the casing and the flat metal fitting and between the electricity storage pack, thereby improving the ease of assembling the pressing member to the electricity storage pack using the mounting surface and the flat metal fitting.

[0013] (3) It is preferable that the metal fitting-side elastic contact portion is configured by a spring piece formed by cutting and bending a part of the flat metal fitting toward the electricity storage pack. The metal fitting-side elastic contact portion can be formed integrally with the flat metal fitting, which improves manufacturability and reduces costs.

[0014] (4) It is preferable that the fitting-side elastic contact portion be configured by a separate spring member attached to the flat fitting. Because the fitting-side elastic contact portion can be configured by a separate spring member attached to the flat fitting, it can be formed with a high degree of design freedom, making it easy to achieve the required spring properties.

[0015] (5) It is preferable that the holding case of the electricity storage pack has a pack-side elastic contact portion that elastically contacts the flat metal fitting. Elastic deformation of the pack-side elastic contact portion provided on the holding case advantageously absorbs tolerances between the opposing surfaces of the mounting surface of the casing and the flat metal fitting and between the electricity storage pack, thereby improving the ease of assembling the pressing member to the electricity storage pack using the mounting surface and the flat metal fitting.

[0016] (6) It is preferable that the pack-side elastic contact portion be configured by an elastic tongue piece provided integrally with the holding case on the flat metal fitting side of the holding case. The pack-side elastic contact portion can be formed integrally with the holding case, which improves manufacturability and reduces costs.

[0017] (7) It is preferable that the pack-side elastic contact portion is configured by a separate spring member attached to the holding case. Because the pack-side elastic contact portion can be configured by a separate spring member attached to the holding case, the pack-side elastic contact portion can be formed with a high degree of design freedom, making it easy to achieve the required spring properties.

[0018] (8) The electricity storage pack is preferably provided with a guide surface that guides the metal fitting-side resilient contact portion into a predetermined position. By providing the electricity storage pack with a guide surface that guides the metal fitting-side resilient contact portion into a predetermined position, the guide surface can easily guide the metal fitting-side resilient contact portion into the predetermined position even if it is deviated from the predetermined position when, for example, the flat metal fitting is placed on the electricity storage pack before being fixed to the housing. As a result, the flat metal fitting can be easily positioned with respect to the electricity storage pack and the housing, improving the ease of assembly of the flat metal fitting and ultimately the manufacturability of the electricity storage unit.

[0019] <Details of the embodiment of the present disclosure> Specific examples of the energy storage unit of the present disclosure will be described below with reference to the drawings. Note that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0020] <Embodiment 1> An electric power storage unit 10 according to a first embodiment of the present disclosure will be described below with reference to FIGS. 1 to 5. The electric power storage unit 10 according to this embodiment is used as a backup electric power storage unit or power supply unit for multiple functions of systems such as steer-by-wire (SBW), brakes, electric power steering (EPS), and autonomous driving in the event of a power failure in, for example, an electric vehicle or hybrid vehicle, and is a relatively high-capacity electric power storage unit. Note that although the electric power storage unit 10 can be placed in any orientation, the following description will be given using the up-down, left-right, and front-to-back directions shown in FIG. 1. Furthermore, in the following description, when multiple identical components are used, only some of the components may be designated by reference numerals, and the reference numerals may be omitted for other components.

[0021] <Energy storage unit 10> As also shown in Figures 2 and 3, the energy storage unit 10 comprises an energy storage pack 16 including an energy storage element 12 and a holding case 14 that holds the energy storage element 12, a housing 18 that houses the energy storage pack 16, and a flat metal fitting 22 that is arranged opposite a metal mounting surface 20 of the housing 18 for the energy storage pack 16 with the energy storage pack 16 interposed therebetween and that is fixed to the housing 18.

[0022] In addition to the electricity storage pack 16 and the flat metal fitting 22, the housing 18 also accommodates a control board 24 that is electrically connected to the electricity storage pack 16 via an appropriate connector, terminal, etc., and a connector 26 that is electrically connected to the control board 24. The connector 26 is exposed at the front opening of the housing 18, and a connector of a counterpart device (not shown) is electrically connected to the connector 26, thereby electrically connecting the electricity storage unit 10 to the counterpart device. A connector cover 28 is provided at the front opening of the housing 18 to prevent water from entering the interior of the housing 18.

[0023] <Energy Storage Pack 16> Although a conventionally known capacitor or the like may be used as the energy storage element 12, in the first embodiment, as shown in Fig. 3, a substantially flat-plate-shaped energy storage element 12 is used. The energy storage element 12 is held by a holder 30. The holder 30 is made of insulating synthetic resin. The outer shape of the holder 30 is substantially rectangular, with the front-to-rear dimension being larger than the left-to-right dimension.

[0024] In the first embodiment, three energy storage elements 12 are provided in an energy storage pack 16. The energy storage elements 12 are arranged spaced apart from one another in the vertical direction, and the energy storage elements 12 (first energy storage element 12a, second energy storage element 12b, and third energy storage element 12c from the top) are held by holders 30 (first holder 30a, second holder 30b, and third holder 30c from the top). Each holder 30 (first to third holders 30a to 30c) has engagement claws 32 and / or engagement frames 34 on its outer circumferential surface, and the first to third holders 30a to 30c, which hold the first to third energy storage elements 12a to 12c, are stacked in the vertical direction as shown in FIGS. 2 and 3 and are releasably assembled by the engagement claws 32 and the engagement frames 34. In addition, appropriate insulating structures are provided between the upper and lower storage elements 12 and on the underside of the lowest third storage element 12c, so that there is no electrical conduction between storage elements 12 arranged opposite each other in the vertical direction and between third storage element 12c and housing 18 (lower case 40 described later) on which storage pack 16 is placed.

[0025] Case lid 36 is superimposed on and assembled to the uppermost first holder 30a from above. Case lid 36 is formed from an insulating synthetic resin and has a generally rectangular flat plate shape with an outer shape generally identical to that of each of the holders 30 (first to third holders 30a to 30c). Engagement claws 32 are provided on the outer circumferential surface of case lid 36, and engage with engagement frame 34 of first holder 30a, thereby releasably assembling case lid 36 and first holder 30a. By assembling case lid 36 to first holder 30a from above in this manner, first energy storage element 12a held in first holder 30a is covered from above by insulating case lid 36, preventing electrical conduction between first energy storage element 12a and flat plate fitting 22 that faces it in the vertical direction, as described below. Therefore, in embodiment 1, the holding case 14 that holds each storage element 12 (first to third storage elements 12a to 12c) in the storage pack 16 is configured to include each holder 30 (first to third holders 30a to 30c) and a case lid portion 36.

[0026] In addition, a portion that protrudes outward in the left-right direction is formed in the middle of the front-to-rear direction of the case lid portion 36, with a predetermined front-to-rear dimension, and the upper surface of this portion that protrudes outward in the left-to-right direction forms a contact surface 38 against which the metal fitting side elastic contact portion 54 of the flat plate metal fitting 22, which will be described later, elastically abuts.

[0027] In addition, each storage element 12 (first to third storage elements 12a to 12c) is electrically connected to a bus bar having, for example, terminals protruding upward, and these terminals are directly or indirectly connected to a control board 24 located above the storage pack 16 through each holder 30 and / or case lid portion 36 located above, so as to be electrically conductive.

[0028] <Case 18> The housing 18 is composed of a generally box-shaped lower case 40 that opens upward and an generally box-shaped upper case 42 that opens downward. That is, the upper case 42 is placed on top of the lower case 40 so as to cover the upper opening of the lower case 40, and the lower case 40 and the upper case 42 are fixed to each other to form the housing 18. In the first embodiment, both the lower case 40 and the upper case 42 are made of metal.

[0029] Specifically, the lower case 40 has a substantially rectangular bottom wall 44 and a lower peripheral wall 46 that protrudes upward from the outer periphery of the bottom wall 44. The upper case 42 has a substantially rectangular upper bottom wall 48 and an upper peripheral wall 50 that protrudes downward from the outer periphery of the upper bottom wall 48. The electricity storage pack 16 is placed on the bottom wall 44 of the lower case 40 so that the electricity storage pack 16 is housed within the lower case 40, and the upper surface of the bottom wall 44 of the lower case 40 is the placement surface 20 on which the electricity storage pack 16 is placed.

[0030] <Flat metal fittings 22> The flat metal fitting 22 has a substantially square shape in a plan view, and is made of metal such as iron (including alloys) or aluminum (including alloys). The outer peripheral edge of the flat metal fitting 22 is bent upward to improve rigidity.

[0031] Approximately rectangular through-windows 52 that penetrate in the plate thickness direction (up and down direction) are provided on both left and right sides of the flat plate fitting 22. Each through-window 52 is formed in the middle part of the flat plate fitting 22 in the front-to-rear direction, with predetermined front-to-rear and left-to-right dimensions.

[0032] <Metal fitting side elastic contact part 54> A metal fitting-side resilient contact portion 54 that curves downward and protrudes outward in the left-right direction is provided on the inner peripheral surface of each through-window 52 on the inside in the left-right direction. Each metal fitting-side resilient contact portion 54 has a smaller front-to-rear dimension than each through-window 52, ​​and spaces (gaps) are provided on three sides around each metal fitting-side resilient contact portion 54 (both front-to-rear directions and outward in the left-to-right directions). This allows each metal fitting-side resilient contact portion 54 to elastically deform in the thickness direction. In the first embodiment, each metal fitting-side resilient contact portion 54 is formed by a spring piece formed by cutting and raising a portion of the flat metal fitting 22 downward, i.e., toward the electricity storage pack 16 as described below.

[0033] Bolt insertion holes 56 are formed in the four corners of the periphery of the flat plate metal fitting 22, and bolts 58 that are inserted into the bolt insertion holes 56 are fastened to the lower peripheral wall portion 46 of the lower case 40 of the housing 18. In this way, the flat plate metal fitting 22 is fixed from above to the upper opening of the lower case 40 that houses the electricity storage pack 16, so as to cover the electricity storage pack 16. As a result, the flat plate metal fitting 22 and the case lid portion 36 that constitutes the upper end portion of the electricity storage pack 16 face each other in the vertical direction, and each metal fitting-side elastic contact portion 54 that protrudes downward from the flat plate metal fitting 22 is in elastic contact with each abutment surface 38 of the case lid portion 36. The state in which the flat plate metal fitting 22 and the case lid portion 36 face each other in the vertical direction, and each metal fitting-side elastic contact portion 54 is in elastic contact with each abutment surface 38, is shown in Figures 4 and 5.

[0034] That is, when the flat metal fitting 22 is fixed to the upper opening of the lower case 40 with the bolts 58, the metal fitting-side resilient contact portions 54 are pressed against the respective abutment surfaces 38, and the metal fitting-side resilient contact portions 54 are elastically deformed upward. The state of the metal fitting-side resilient contact portions 54 before elastic deformation is shown by the two-dot chain line in Fig. 5. The elastic restoring force of each of these metal fitting-side resilient contact portions 54 presses each of the metal fitting-side resilient contact portions 54 against the respective abutment surfaces 38, and the case lid 36, and therefore the electricity storage pack 16, are urged downward. As a result, the electricity storage pack 16 is sandwiched in the vertical direction between the flat metal fitting 22 and the upper surface (mounting surface 20) of the bottom wall portion 44 of the lower case 40 of the housing 18.

[0035] <Pressure member 60> As will be described later, when each of the energy storage elements 12 (first to third energy storage elements 12a to 12c) expands, a left-right intermediate portion of the case lid 36 bulges upward and comes into contact with a left-right intermediate portion of the flat plate fitting 22. As a result, an expansion suppressing portion 59 is formed by the left-right intermediate portion of the flat plate fitting 22 (between the left-right direction of each fitting-side elastic contact portion 54, 54), and the mounting surface 20 and the flat plate fitting 22 (particularly the expansion suppressing portion 59) form a pressure member 60 that suppresses expansion of each of the energy storage elements 12 (first to third energy storage elements 12a to 12c). Note that, as also shown in FIG. 5 , before each of the energy storage elements 12 (first to third energy storage elements 12a to 12c) expands, the left-right intermediate portion of the flat plate fitting 22 (expansion suppressing portion 59) and the left-right intermediate portion of the case lid 36 are spaced apart from each other in the up-down direction.

[0036] <Assembly process of the power storage unit 10> Next, a specific example of the process of assembling the electricity storage unit 10 will be described. Note that the process of assembling the electricity storage unit 10 is not limited to the following description.

[0037] First, each energy storage element 12 (first to third energy storage elements 12a to 12c) is housed in a corresponding holder (first to third holders 30a to 30c), and first to third holders 30a to 30c are then stacked vertically with an appropriate insulating structure interposed between them. Furthermore, case lid 36 is stacked from above on first holder 30a holding first energy storage element 12a and assembled. This completes energy storage pack 16.

[0038] The electricity storage pack 16 is placed on the upper surface (mounting surface 20) of the bottom wall portion 44 of the lower case 40, and the electricity storage pack 16 is accommodated in the lower case 40. Thereafter, the flat metal fitting 22 is placed over the electricity storage pack 16 from above, and the flat metal fitting 22 is fixed to the lower case 40 with bolts 58. As a result, the metal fitting-side elastic contact portions 54 are pressed against the abutment surfaces 38 of the case lid 36, and the metal fitting-side elastic contact portions 54 are elastically deformed upward. As a result, the electricity storage pack 16 is sandwiched between the mounting surface 20 and the flat metal fitting 22 in the vertical direction.

[0039] The control board 24 is then placed over the flat metal fitting 22 from above and fixed with bolts 62 so as to cover the upper opening of the lower case 40, and terminals protruding upward from the electricity storage pack 16 are electrically connected to the control board 24. Furthermore, with the connectors 26 electrically connected to the control board 24, the connectors 26 are fixed to the lower case 40. The connectors 26 may be mounted on the control board 24 in advance, or the control board 24 and the connectors 26 may be fixed integrally to the lower case 40. The connector cover 28 is then placed over the lower case 40 so as to cover the connectors 26. With the electricity storage pack 16, flat metal fitting 22, control board 24, connectors 26, and connector cover 28 fixed to the lower case 40 in this manner, the upper case 42 is placed over the lower case 40 from above and fixed thereto. This completes the electricity storage unit 10.

[0040] In the energy storage unit 10 of the first embodiment manufactured as described above, the energy storage packs 16 are sandwiched vertically between the mounting surface 20 of the lower case 40 that constitutes the housing 18 and the flat metal fittings 22 that are fixed to the lower case 40. In particular, if gas is generated inside each energy storage element 12, for example, each energy storage element 12 is likely to expand vertically, i.e., in the plate thickness direction, because it has a substantially flat plate shape. However, because the lower case 40 and the flat metal fittings 22 that sandwich the energy storage packs 16 on both the top and bottom sides are made of metal and have sufficient rigidity, the left-right intermediate portions (expansion suppressing portions 59) of the mounting surface 20 and the flat metal fittings 22 act as pressure members 60, thereby suppressing the expansion of each energy storage element 12. Furthermore, since the lower case 40 (mounting surface 20) constituting the housing 18 of the energy storage unit 10 and the flat metal fitting 22 fixed to the lower case 40 and positioned inside the housing 18 are used as the pressure member 60, no pressure member with a complex structure is required, and the energy storage unit 10 is prevented from becoming larger.

[0041] The flat metal fitting 22 has metal fitting-side resilient contact portions 54 that resiliently contact the electricity storage pack 16. The elastic deformation of the metal fitting-side resilient contact portions 54 absorbs the tolerances of the various components, improving ease of assembly. The metal fitting-side resilient contact portions 54 also urge the electricity storage pack 16 downward, ensuring stable accommodation within the lower case 40 without rattle. In particular, in the first embodiment, the electricity storage pack 16 is configured by assembling the holders 30 (first to third holders 30a to 30c) that hold the energy storage elements 12 (first to third energy storage elements 12a to 12c) and the case lid 36. Therefore, rattle between the case lid 36 and the first holder 30a and between the holders 30 can be prevented by the case lid 36 being pressed from above by the metal fitting-side resilient contact portions 54.

[0042] In the first embodiment, each metal fitting-side resilient contact portion 54 is configured by a spring piece formed by cutting and raising a portion of the flat metal fitting 22 downward, toward the electricity storage pack 16. This allows each metal fitting-side resilient contact portion 54 to be formed integrally with the flat metal fitting 22, and allows each metal fitting-side resilient contact portion 54 to be formed easily and inexpensively, which in turn improves the manufacturability of the electricity storage unit 10 and reduces costs.

[0043] <Embodiment 2> Next, an energy storage unit according to a second embodiment of the present disclosure will be described using Figures 6 and 7. In the second embodiment, the only difference from the energy storage unit 10 of the first embodiment is the shape of the flat metal fitting 72 having the metal fitting-side elastic contact portion 70, and therefore other parts are not shown in the drawings. In the following description, members and parts that are substantially the same as those in the previous embodiment are given the same reference numerals in the drawings, and detailed description thereof will be omitted.

[0044] <Metal fitting side elastic contact portion 70> In the first embodiment, each fitting-side resilient contact portion 54 was formed integrally with the flat plate fitting 22, but in the second embodiment, each fitting-side resilient contact portion 70 is configured from a spring member separate from the flat plate fitting 72, and each fitting-side resilient contact portion 70 is attached to the flat plate fitting 72. In the second embodiment, the fitting-side resilient contact portions 70 are attached to two locations spaced apart in the front-to-rear direction on both the left and right sides of the flat plate fitting 72, but because each fitting-side resilient contact portion 70 has the same shape, only one fitting-side resilient contact portion 70 will be described.

[0045] The fitting-side resilient contact portion 70 can be formed, for example, by bending a substantially rectangular piece of metal using press working or the like, and extends in the left-right direction as a whole. One end of the fitting-side resilient contact portion 70 is provided with a curved portion 74 that essentially functions as a spring, and this curved portion 74 is curved so that it is convex downward. A flat portion 76 that extends parallel to the flat plate fitting 72 is provided continuously with the curved portion 74, and the other end of the fitting-side resilient contact portion 70 is provided with a vertical portion 78 that extends in a direction perpendicular to the flat plate fitting 72. A substantially rectangular engagement hole 80 that extends in the front-rear direction is provided in the vertical portion 78 and penetrates it in the left-right direction.

[0046] <Flat metal fittings 72> In the flat metal fitting 72, a through window 82 having a front-to-rear dimension that allows the fitting-side resilient contact portion 70 to be inserted is formed at the attachment location of the flat metal fitting 72, penetrating in the plate thickness direction (up-down direction) with a predetermined left-to-right dimension. This through window 82 is partitioned in the left-to-right intermediate portion by a partition portion 84 that extends in the front-to-rear direction, dividing it into a first window portion 86 on the inside in the left-to-right direction and a second window portion 88 on the outside in the left-to-right direction. An engagement protrusion 90 that protrudes outward in the left-to-right direction into the first window portion 86 is provided on the inside inner peripheral surface of the through window 82 in the left-to-right direction (i.e., the inside inner peripheral surface of the first window portion 86 in the left-to-right direction).

[0047] When attaching the above-described fitting-side resilient contact portion 70 to the flat fitting 72, the fitting-side resilient contact portion 70 is inserted into the second window portion 88 of the through-window 82 from the curved portion 74 side, which is one end of the fitting-side resilient contact portion 70, and in this inserted state is rotated relative to the flat fitting 72 about a rotation axis extending in the front-to-rear direction so that the flat portion 76 of the fitting-side resilient contact portion 70 and the partition portion 84 of the through-window 82 are parallel to each other. The fitting-side resilient contact portion 70 is then pressed from above into the flat fitting 72 so that the flat portion 76 and the partition portion 84 overlap, thereby engaging the engaging protrusion 90 with the engaging hole 80. As a result, the engaging protrusion 90 fits into the engaging hole 80 and the flat portion 76 is supported on the partition portion 84, so that the fitting-side resilient contact portion 70 is stably attached to the flat fitting 72. When the fitting-side resilient contact portion 70 is attached to the flat metal fitting 72, the curved portion 74 is arranged in a downwardly convex manner below the flat metal fitting 72. After the fitting-side resilient contact portion 70 is attached to the flat metal fitting 72 as described above, it may be fixed even more firmly by welding, adhesive, or the like.

[0048] In the second embodiment as well, the flat metal fittings 72 having the metal fitting-side resilient contact portions 70 are fixed to the case lid 36 of the electricity storage pack 16 so as to face each other in the up-down direction, so that the curved portions 74 of the metal fitting-side resilient contact portions 70 are pressed against the contact surfaces 38 of the case lid 36. This makes it possible to achieve the same effects as in the first embodiment. In particular, by forming the metal fitting-side resilient contact portions 70 separately from the flat metal fittings 72, it is possible to appropriately change the material and shape of the metal fitting-side resilient contact portions 70 in accordance with the required spring properties, and it is also possible to more stably achieve the tolerance absorption effect and rattle prevention effect of the electricity storage pack 16 by the metal fitting-side resilient contact portions 70.

[0049] <Embodiment 3> Next, an energy storage unit according to a third embodiment of the present disclosure will be described with reference to Figures 8 to 10. In the third embodiment, the only difference from the energy storage unit 10 of the first embodiment is the shape of the case lid 100 that constitutes the energy storage pack 16, and therefore other parts are not shown in the drawings. As in the first embodiment, for example, a holder 30 (first holder 30a) that holds an energy storage element 12 (first energy storage element 12a) can be attached to this case lid 100 from below, and a flat metal fitting 22 having the same shape as in the first embodiment can be arranged from above in a state where they face each other in the vertical direction.

[0050] <Guide surface 102> In the third embodiment, guide surfaces 102 that gradually slope downward outward in the left-right direction are provided on both left and right sides of the middle portion of the case lid 100 in the front-rear direction. In addition, inclined surfaces 104 that slope gradually outward in the front-rear direction as they rise are provided on both front-rear sides of each of these guide surfaces 102. These inclined surfaces 104 are also inclined outward in the front-rear direction as they extend outward in the left-right direction, and the minimum facing distance between the inclined surfaces 104 that face each other in the front-rear direction (i.e., the facing distance in the front-rear direction at the inner end of the inclined surfaces 104 in the left-right direction) is approximately equal to or slightly larger than the front-rear dimension of each metal fitting-side elastic contact portion 54 of the flat plate fitting 22. Figures 9 and 10 show a state in which the case lid 100 and the flat plate fitting 22 shaped in this way face each other in the top-bottom direction, and each metal fitting-side elastic contact portion 54 of the flat plate fitting 22 and the case lid 100 are in elastic contact. The state of each metal fitting side elastic contact portion 54 before elastic deformation is also shown by the two-dot chain line in FIG.

[0051] By providing guide surfaces 102 on both the left and right sides of the case lid 100, in the third embodiment, the metal fitting-side resilient contact portions 54 and the guide surfaces 102 come into contact with each other before the flat plate fitting 22 is fixed to the lower case 40 with the bolts 58. Then, by fixing the flat plate fitting 22 to the upper opening of the lower case 40 with the bolts 58 in the same manner as in the first embodiment, in the third embodiment, as shown in Fig. 10 , the metal fitting-side resilient contact portions 54 are pressed against the guide surfaces 102 and are elastically deformed upward. The elastic restoring force of each of these metal fitting-side resilient contact portions 54 presses each metal fitting-side resilient contact portion 54 against the guide surfaces 102, and the case lid 100, and therefore the electricity storage pack 16, is urged downward.

[0052] The energy storage unit of embodiment 3 having such a case lid 100 can also achieve the same effects as the energy storage unit 10 of embodiment 1. In particular, in embodiment 3, guide surfaces 102 are provided on both left and right sides of the case lid 100 so that when the flat plate fitting 22 is placed on the case lid 100 (before the flat plate fitting 22 is fixed with the bolts 58), the metal fitting-side resilient contact portions 54 and the guide surfaces 102 come into contact with each other in the left and right direction. As a result, the metal fitting-side resilient contact portions 54 are guided by the guide surfaces 102, and the flat plate fitting 22 is held in a specified position in the left and right direction relative to the case lid 100. Furthermore, on both front-rear sides of each guide surface 102, inclined surfaces 104 are provided that gradually incline outward in the front-rear direction as they extend upward, and these inclined surfaces 104 also guide and hold the metal fitting-side resilient contact portions 54 in a specified position in the front-rear direction. In other words, when assembling the flat plate fitting 22, by placing the flat plate fitting 22 on the case lid portion 100, each fitting side elastic contact portion 54 of the flat plate fitting 22 is guided by each guide surface 102 and each inclined surface 104 into a predetermined concave position formed on the case lid portion 100, and the flat plate fitting 22 is held in a positioned state on the case lid portion 100, thereby improving assembly ease.

[0053] <Embodiment 4> Next, an energy storage unit according to a fourth embodiment of the present disclosure will be described with reference to Figures 11 and 12. In the fourth embodiment, the shape of the case lid 110 that constitutes the holding case for the energy storage pack is different from that of the energy storage unit 10 of the first embodiment, but the basic structure is the same, and therefore other parts are not shown in the drawings. For example, as in the first embodiment, a holder 30 (first holder 30a) that holds an energy storage element 12 (first energy storage element 12a) can be assembled to this case lid 110 from below, and a flat metal fitting 112 (shown by a two-dot chain line in Figure 12) can be arranged from above in a state where they face each other in the vertical direction, as in the first embodiment.

[0054] In the first to third embodiments, the flat metal fittings 22, 72 have metal fitting-side elastic contact portions 54, 70 that elastically contact the case lid portion 36, 100 that constitutes the electricity storage pack 16. However, in the fourth embodiment, the case lid portion 110 that constitutes the electricity storage pack has a pack-side elastic contact portion 114 that elastically contacts the flat metal fitting 112. In particular, in the fourth embodiment, the pack-side elastic contact portion 114 is formed by a spring member that is separate from the case lid portion 110 of the holding case, and this pack-side elastic contact portion 114 is attached to the case lid portion 110. Furthermore, in the fourth embodiment, the pair of pack-side elastic contact portions 114, 114 are provided spaced apart from each other in the front-to-rear direction. Note that in Fig. 11, the front pack-side elastic contact portion 114 is shown in a state before being assembled to the case lid portion 110, and the rear pack-side elastic contact portion 114 is shown in a state assembled to the case lid portion 110.

[0055] The case lid 110 is provided with a substantially rectangular through-window 116 in the left-right central portion at the attachment position of each pack-side elastic contact portion 114. That is, a pair of through-windows 116, 116 spaced apart in the front-rear direction are provided in the case lid 110 and penetrate the case lid 110 in the thickness direction (up-down direction). A partition 118 extending in the front-rear direction is provided in the left-right central portion of each through-window 116, and this partition 118 divides each through-window 116 into a pair of insertion holes 120, 120 spaced apart in the left-right direction. The partition 118 protrudes above the top surface of the case lid 110, and this upward-protruding partition 118 is provided with a pair of engaging protrusions 122, 122 protruding on both left-right sides. Furthermore, a pair of engaging grooves 124, 124 extending in the front-rear direction are provided at both left-right ends of the case lid 110 at the formation position of each through-window 116. Each of these through windows 116 and each of the engagement grooves 124 are formed to have approximately the same dimensions in the front-rear direction.

[0056] <Flat Plate Metal Fitting 112> The flat plate fitting 112 of embodiment 4 is not provided with a fitting-side elastic contact portion and may, for example, be in the shape of a substantially flat plate overall. Approximately rectangular openings 126 are provided in the left-right center of the flat plate fitting 112, spaced apart from each other in the front-rear direction, to avoid interference with the partition portion 118 and a connecting portion 130 (described later). Note that in embodiment 4, for example, the flat plate fitting 112 is provided with expansion suppressing portions 127 on both left and right sides of the opening 126, and portions of the case lid portion 110 on both left and right sides of the through-windows 116 (described later) that bulge upward as the energy storage elements 12 expand come into contact with the expansion suppressing portions 127 via curved portions 128 of the pack-side elastic contact portions 114 (described later), thereby suppressing the expansion of the energy storage elements 12.

[0057] <Pack side elastic contact portion 114> The front and rear pack-side resilient contact portions 114, 114 have the same shape, and therefore only one of the pack-side resilient contact portions 114 will be described below. The pack-side resilient contact portion 114 can be formed, for example, by bending a substantially rectangular metal piece by press working or the like, and extends in the left-right direction as a whole. Curved portions 128, which essentially function as springs, are provided on both sides of the pack-side resilient contact portion 114 in the longitudinal direction (left-right direction), and each curved portion 128 is curved so as to be convex upward. The curved portions 128 on both sides are connected by a connecting portion 130, which is generally trough-shaped and opens downward so as to cover the partition portion 118 from above. The lower left and right ends of the connecting portion 130 are connected to the curved portions 128 on both sides by bent portions 132. Furthermore, engagement holes 134 that engage with the engagement protrusions 122 are provided in the left and right wall portions that constitute the connecting portion 130. Furthermore, at the end (both ends in the left and right direction) of each curved portion 128 opposite to the side connected to the connecting portion 130, an engaging claw 136 is provided that protrudes downward.

[0058] When attaching the pack-side elastic contact portion 114 to the case lid 110, as shown in Fig. 11 , the pack-side elastic contact portion 114 and the case lid 110 are positioned opposite each other in the vertical direction so that the connecting portion 130 covers the partition portion 118 from above. In this state, by pushing the pack-side elastic contact portion 114 from above, the bent portions 132, which are connecting portions between the curved portions 128 and the connecting portion 130, are inserted into the pair of insertion holes 120, 120 in the center in the horizontal direction, and the engaging claws 136 are inserted into the pair of engaging grooves 124, 124 at both ends in the horizontal direction. Furthermore, the connecting portion 130 is placed over the partition portion 118 from above, and the engaging protrusions 122 are engaged with the engaging holes 134. As a result, in addition to the recessed and projecting fit between the engaging protrusions 122 and the engaging holes 134, the engaging claws 136 are inserted into the engaging grooves 124, effectively preventing misalignment of the pack-side elastic contact portion 114 in the left-right direction relative to the case lid 110, and the pack-side elastic contact portion 114 is stably attached to the case lid 110. When the pack-side elastic contact portion 114 is attached to the case lid 110, each curved portion 128 is arranged so as to convex upward. After the pack-side elastic contact portion 114 is attached to the case lid 110 as described above, it may be further firmly fixed by welding, adhesive, or the like.

[0059] 12 , with the case lid 110 having the pack-side elastic contact portions 114 attached in this manner, the flat plate metal fitting 112 and the case lid 110 are brought into vertical opposition while the partition portion 118 and the connecting portion 130 are inserted into the opening 126. This causes the flat plate metal fitting 112 and the curved portions 128 to overlap in the vertical direction. From this state, by fixing the flat plate metal fitting 112 to the upper opening of the lower case 40 with the bolts 58, the curved portions 128 are pressed from below against the flat plate metal fitting 112 and come into elastic contact. As a result, the curved portions 128 elastically deform downward, and the elastic restoring force of this elastic deformation urges the case lid 110, i.e., the electricity storage pack, downward, in a direction away from the flat plate metal fitting 112.

[0060] The energy storage unit of embodiment 4 having such a case lid 110 can also achieve the same effects as the energy storage unit 10 of embodiment 1. In particular, by forming each pack side resilient contact portion 114 separately from the case lid portion 110, it is possible to appropriately change the material, shape, etc. of each pack side resilient contact portion 114 in accordance with the required spring properties, and for example, it is also possible to form each pack side resilient contact portion 114 from metal. This allows each pack side resilient contact portion 114 to more stably achieve the tolerance absorption effect, the effect of preventing rattle in the energy storage pack, etc.

[0061] <Embodiment 5> Next, an electricity storage unit according to a fifth embodiment of the present disclosure will be described with reference to Fig. 13. In the fifth embodiment, the shape of the case lid 140 constituting the holding case of the electricity storage pack is different from that of the electricity storage unit 10 of the first embodiment, but since the basic structure is the same, other parts are not shown in the drawings. In the fourth embodiment, the pack-side elastic contact portion 114 was attached to the case lid 110 as a separate body, but in the fifth embodiment, the pack-side elastic contact portion 142 is provided integrally with the case lid 110.

[0062] In embodiment 5, the pack side elastic contact portion 142 is provided at two locations spaced apart in the front-to-back direction on both the left and right sides of the case lid portion 140, but since each pack side elastic contact portion 142 has the same shape, only one pack side elastic contact portion 142 will be described.

[0063] <Pack side elastic contact portion 142> A substantially rectangular through-window 144 is provided at a predetermined position in the case lid 140, penetrating it in the thickness direction (vertical direction). The inner peripheral surface of the through-window 144, located on the outer side in the left-right direction, is provided with a pack-side resilient contact portion 142 that curves upward to form a convex shape and protrudes inward in the left-right direction. The pack-side resilient contact portion 142 has smaller front-rear and left-right dimensions than the through-window 144, and spaces (gaps) are provided on three sides (both front-rear directions and inner left-right directions) around the pack-side resilient contact portion 142. This allows the pack-side resilient contact portion 142 to resiliently deform in the thickness direction. In the fifth embodiment, the pack-side resilient contact portion 142 is configured as a resilient tongue piece integrally provided on the upper side of the case lid 140, i.e., on the flat metal plate side (not shown). The flat metal plate in the fifth embodiment may be a substantially flat plate-like member as a whole, similar to the flat metal plate 112 in the fourth embodiment, and the opening 126 in the fourth embodiment may not be provided.

[0064] In the fifth embodiment as well, the flat metal fittings are fixed to face each other in the vertical direction relative to the case lid 140 having the pack side resilient contact portions 142, so that the pack side resilient contact portions 142 are pressed against the flat metal fittings. This can achieve the same effects as in the fourth embodiment. In particular, in the fifth embodiment, the pack side resilient contact portions 142 are formed integrally with the case lid 140, so that the pack side resilient contact portions 142 can be formed easily and inexpensively, which in turn improves the manufacturability of the electricity storage unit and reduces costs.

[0065] <Modification> Although the first to fifth embodiments have been described above as specific examples of the present disclosure, the present disclosure is not limited to these specific descriptions. Modifications, improvements, etc., within the scope of achieving the object of the present disclosure, are included in the present disclosure. For example, the following modifications of the embodiments are also included in the technical scope of the present disclosure.

[0066] (1) In the above embodiment, both the upper case 42 and the lower case 40 constituting the metal housing 18 are made of metal. However, for example, the upper case may be made of synthetic resin. Furthermore, it is sufficient that at least the bottom wall portion of the lower case, including the mounting surface constituting the pressure member, is made of metal. This makes it possible to suppress the expansion of the energy storage device, which expands mainly in the vertical direction. That is, the peripheral wall portion of the lower case may be made of synthetic resin, and the lower case may be made of a composite material of metal and synthetic resin. However, if the energy storage device is expected to expand in the left-right or front-back directions, for example, it is preferable that the peripheral wall portion is also made of metal, and the entire lower case be made of metal.

[0067] (2) In the second embodiment, the separate fitting-side elastic contact portions 70 were assembled from above to the flat fitting 72 and secured by recess-and-projection fitting engagement. However, the separate fitting-side elastic contact portions may be secured to the flat fitting by welding or adhesive. In this case, the flat fitting need not be provided with a through-window for assembling the fitting-side elastic contact portions. Similarly, in the fourth embodiment, the separate pack-side elastic contact portions 114 were assembled from above to the case lid 110, but they may be secured by welding or adhesive.

[0068] (3) The shapes of the fitting-side resilient contact portions provided on the flat fittings and the pack-side resilient contact portions provided on the holding case (case lid) are not limited. For example, in the first embodiment, each fitting-side resilient contact portion 54 protrudes outward in the left-right direction from the inner circumferential surface on the inside of each through window 52 in the left-right direction. However, each fitting-side resilient contact portion may protrude inward in the left-right direction from the inner circumferential surface on the outside of each through window. Similarly, in the second embodiment, the curved portion 74 of each fitting-side resilient contact portion 70 may be provided on the inner side in the left-right direction, and in the fifth embodiment, each pack-side resilient contact portion 142 may protrude outward in the left-right direction from the inner circumferential surface on the inside of each through window 144 in the left-right direction. Furthermore, in the third embodiment, each fitting-side resilient contact portion 54 may protrude inward in the left-right direction, and the position of the guide surface that contacts the fitting-side resilient contact portion and guides the flat fitting 22 to a specified position may be changed depending on the protruding direction of the fitting-side resilient contact portion, etc. In the above embodiment, both the metal fitting side elastic contact portion and the pack side elastic contact portion protrude and extend in the left-right direction, but they may also protrude and extend in the front-to-rear direction instead of or in addition to the left-to-right direction.

[0069] (4) In the above-described embodiment, a plurality of metal fitting side elastic contact portions 54, 70 or a plurality of pack side elastic contact portions 114, 142 are provided, respectively. However, the above-described embodiment is merely an example, and the number of metal fitting side elastic contact portions or pack side elastic contact portions may be one, or a number of metal fitting side elastic contact portions or pack side elastic contact portions different from that in the above-described embodiment may be provided.

[0070] (5) At least two of the above-described embodiments 1 to 5 may be combined and employed. For example, an integral fitting-side elastic contact portion as in embodiment 1 may be provided on one side of the flat metal fitting in the left-right direction, or a separate fitting-side elastic contact portion as in embodiment 2 may be attached to the other side of the left-right direction. Similarly, a separate pack-side elastic contact portion as in embodiment 4 may be attached to one side of the case lid in the front-rear direction, or an integral pack-side elastic contact portion as in embodiment 5 may be provided on the other side of the front-rear direction. Furthermore, when pack-side elastic contact portions 114, 142 are provided on the case lid portions 110, 140 as in embodiments 4 and 5, a guide surface that guides the flat metal fitting to a specified position may be provided on the underside of the flat metal fitting so as to come into contact with the pack-side elastic contact portion. Furthermore, for example, the fitting-side elastic contact portion and the pack-side elastic contact portion may be combined and employed. For example, a fitting-side elastic contact portion may be provided on one side of the flat metal fitting in the left-right direction, and a pack-side elastic contact portion may be provided on the other side of the holding case (case lid) in the left-right direction.

[0071] (6) When a separate metal fitting side elastic contact portion or pack side elastic contact portion is provided on the flat metal fitting or the holding case (case lid portion), it is not limited to a metal piece (leaf spring) having a curved portion as in the above embodiment, but may also be, for example, a coil spring.

[0072] (7) In the first embodiment, before the expansion of each energy storage element 12 (first to third energy storage elements 12a to 12c), the expansion suppression portion 59, which is the left-right intermediate portion of the flat metal fitting 22, and the left-right intermediate portion of the case lid portion 36 were spaced apart in the vertical direction. However, before the expansion of the energy storage element, the left-right intermediate portion of the flat metal fitting (expansion suppression portion) and the left-right intermediate portion of the case lid portion may be in contact with each other in the vertical direction.

[0073] (8) The specific shape of the energy storage pack is not limited as long as it includes energy storage elements and a holding case that holds the energy storage elements. For example, the number of energy storage elements is not limited, and the number may be one, two, four, or more. The holders that hold the energy storage elements may be provided in a number corresponding to the number of energy storage elements and may be stacked and assembled as in the above embodiment, or may be, for example, a single box-like shape that houses all of the energy storage elements.

[0074] (9) In the energy storage unit of the present disclosure, the specific structure of the housing that houses the energy storage pack is not limited, and for example, the structure for fastening the flat metal fitting to the housing (lower case) for the energy storage pack is not limited. For example, the flat metal fitting may be fastened to the upper case that constitutes the housing. [Explanation of symbols]

[0075] 10. Energy storage unit (embodiment 1) 12 Energy storage element 12a first storage element 12b second storage element 12c Third storage element 14 Holding case 16 Energy Storage Pack 18. Cabinet 20 Placement surface 22 Flat metal fittings 24 Control board 26 Connectors 28 Connector cover 30 Holder 30a First holder 30b Second holder 30c 3rd holder 32 Engagement claw 34 Engagement frame body 36 Case lid 38 Contact surface 40 Lower case 42 Upper Case 44 Bottom wall 46 Lower peripheral wall 48 Upper bottom wall 50 Upper peripheral wall 52 Through window 54 Metal fitting side elastic contact part 56 Bolt insertion hole 58 volts 59 Expansion suppression section 60 Pressure member 62 volts 70 Metal fitting side elastic contact portion (embodiment 2) 72 Flat metal fittings 74 Curved section 76 Flat area 78 Vertical section 80 Engagement hole 82 Through window 84 Partition 86 First window 88 Second window 90 Engagement protrusion 100 Case lid (Embodiment 3) 102 Guide surface 104 Slope 110 Case lid (Embodiment 4) 112 Flat metal fittings 114 Pack side elastic contact part 116 Through window 118 Partition 120 Insertion hole 122 Engagement protrusion 124 Engagement groove 126 Opening 127 Expansion suppression section 128 curved section 130 Connection section 132 Bent section 134 Engagement hole 136 Engagement claw 140 Case lid (embodiment 5) 142 Pack side elastic contact part 144 Through window

Claims

1. an electricity storage pack including an electricity storage element and a holding case that holds the electricity storage element; a control board connected to the electricity storage pack; a housing that houses the electricity storage pack and the control board; a flat metal fitting that is disposed to face a metal mounting surface of the housing for the electricity storage pack with the electricity storage pack interposed therebetween and is fixed to the housing, the mounting surface and the flat metal fitting constitute a pressure member that suppresses expansion of the energy storage elements, the holding case of the electricity storage pack has a pack-side elastic contact portion that is in elastic contact with the flat metal plate, the pack-side elastic contact portion is configured by an elastic tongue piece that is provided integrally with the holding case on the flat metal fitting side of the holding case.

2. The electricity storage unit according to claim 1 , wherein the flat metal fitting has a metal fitting-side elastic contact portion that elastically contacts the electricity storage pack.

3. The electricity storage unit according to claim 2 , wherein the metal fitting-side elastic contact portion is formed of a spring piece formed by cutting and bending a part of the flat metal fitting toward the electricity storage pack.

4. The electricity storage unit according to claim 2 , wherein the metal fitting-side elastic contact portion is formed by a separate spring member attached to the flat metal fitting.

5. The electricity storage unit according to claim 2 , wherein the electricity storage pack is provided with a guide surface that guides the metal fitting side elastic contact portion into a specified position.

Images