Power storage unit

Abstract

This power storage unit includes: a housing; and a power storage cell housed in the housing. The housing includes a case having an opening; and a lid fixed to the case so as to close the opening. The housing includes a storage space and a discharge path which are sandwiched between the lid and the edge of the opening of the case. The storage space has an annular shape surrounding the opening. The discharge path connects the storage space and the outside of the housing.

Description

Energy storage unit

[0001] The present disclosure relates to a power storage unit, and more particularly to a power storage unit including a power storage cell.

[0002] Patent Document 1 discloses an energy storage unit including a cylindrical case with a bottom, energy storage cells housed in the case, and a lid that closes the opening of the case. This energy storage unit employs a structure in which at least a portion of the lid fits into the case when the lid is fixed to the case, thereby preventing foreign matter from entering the case.

[0003] International Publication No. 2016 / 110886

[0004] An energy storage unit according to one aspect of the present disclosure includes a housing and energy storage cells housed in the housing. The housing includes a case having an opening and a lid fixed to the case so as to close the opening. The housing has a storage space and a discharge path sandwiched between an edge of the opening of the case and the lid. The storage space is annular and surrounds the opening. The discharge path connects the storage space to the outside of the housing.

[0005] According to one aspect of the present disclosure, it is possible to prevent water from entering the electricity storage unit through the gap between the lid and the case of the electricity storage unit.

[0006] FIG. 1 is a perspective view of the energy storage unit of the first embodiment. FIG. 2 is an exploded perspective view of the energy storage unit of the first embodiment. FIG. 3 is a front view of the energy storage unit of the first embodiment. FIG. 4 is a front view of the energy storage unit of the first embodiment with a lid removed. FIG. 5 is a rear view of the lid provided on the energy storage unit of the first embodiment. FIG. 6 is a side view of a portion of the energy storage unit of the first embodiment. FIG. 7 is a bottom view of a portion of the energy storage unit of the first embodiment. FIG. 8 is a plan view of a portion of the energy storage unit of the first embodiment. FIG. 9 is a cross-sectional view taken along line A-A in FIG. 3. FIG. 10 is a cross-sectional view taken along line B-B in FIG. 3. FIG. 11 is a front view of the energy storage unit of the second embodiment with a lid removed.

[0007] Although improvements have been made to the waterproofing of the energy storage unit as disclosed in Patent Document 1, in environments where strict waterproofing is required, it is necessary to further prevent water from entering through the gap between the case and the lid of the energy storage unit.

[0008] The present disclosure provides an electricity storage unit that can prevent water from entering the electricity storage unit through a gap between a lid and a case.

[0009] Hereinafter, embodiments of the energy storage unit 9 of the present disclosure will be described with reference to the accompanying drawings. All of the drawings referred to in the following embodiments are schematic diagrams. Therefore, the ratios of the sizes and thicknesses of the components in the drawings do not necessarily reflect the actual dimensional ratios. Furthermore, the materials, values, etc. described in the embodiments are merely preferred examples and are not intended to be limiting.

[0010] 1. Overview An energy storage unit 9 of this embodiment includes a housing 100 and energy storage cells 3 housed in the housing 100. The housing 100 includes a case 1 having an opening 10 and a lid 5 fixed to the case 1 so as to close the opening 10. The housing 100 has a storage space 71 and a discharge path 72 sandwiched between an edge 16 of the opening 10 of the case 1 and the lid 5. The storage space 71 is annular and surrounds the opening 10. The discharge path 72 connects the storage space 71 to the outside of the housing 100.

[0011] According to the embodiment, even if water attempts to enter the housing 100 through a gap between the case 1 and the lid 5 in the housing 100, the water is stored in the storage space 71, and the water in the storage space 71 can be discharged to the outside of the housing 100 through the discharge path 72. Therefore, water can be prevented from entering the electricity storage unit 9 through a gap between the lid 5 and the case 1 in the electricity storage unit 9.

[0012] 2. First Embodiment (1) Overall Configuration The power storage unit 9 of the first embodiment is used in various electronic devices, electrical devices, industrial devices, automobiles, etc., and is configured to assist power, back up power, etc. When the power storage unit 9 of the first embodiment is mounted on an automobile, for example, it can charge the power storage cells 3 (described later) provided in the power storage unit 9 with power supplied from the automobile battery.

[0013] As shown in Figures 1 and 2, the energy storage unit 9 includes a box-shaped case 1 having an opening 10, a holder 2 housed inside the case 1, at least one energy storage cell 3 held by the holder 2, a circuit board 4 connected to the holder 2, a lid 5 that closes the opening 10 of the case 1, and at least one fixing member 8 that fixes the lid 5 to the case 1.

[0014] In the first embodiment, a plurality of storage cells 3 are held in the holder 2. The lid 5 is fixed to the case 1 with a plurality of fixing members 8. More specifically, after the holder 2 holding five storage cells 3, the circuit board 4, and the lid 5 are joined together, the holder 2 holding the five storage cells 3 and the circuit board 4 are housed in the case 1, and the opening 10 of the case 1 is covered with the lid 5. The lid 5 is fixed to the case 1 with four fixing members 8. Hereinafter, the state in which the lid 5 is fixed to the case 1 will be referred to as the "lid fixed state."

[0015] (2) Housing The housing 100 has a rectangular parallelepiped shape. Note that a rectangular parallelepiped shape refers to a shape that can be regarded as a rectangular parallelepiped overall, and may have slight distortions, protrusions, irregularities, rounded vertices, rounded sides, etc.

[0016] The surface of the outer surface of the housing 100 facing the lid 5 will hereinafter be referred to as the first surface 181 or the front surface 181. The front surface 181 is rectangular. A rectangular shape refers to a shape that can be considered rectangular overall, and may have slight distortions, protrusions, irregularities, rounded vertices, etc. The front surface 181 is also the outer surface (front surface 511) of the lid 5. That is, the front surface 511 of the lid 5 is rectangular. The front surface 181 has a shape that is long in one direction, i.e., has two long sides and two short sides. The surface of the outer surface of the housing 100 that is along one of the two long sides of the front surface 181 will hereinafter be referred to as the second surface 182 or the installation surface 182, and the surface opposite the installation surface 182, i.e., the surface along the other of the two long sides of the front surface 181, will hereinafter be referred to as the third surface 183 or the top surface 183. The surfaces of the outer surface of the housing 100 that are along the two short sides of the front surface 181 will hereinafter also be referred to as fourth surfaces 184 or side surfaces 184. The surfaces of the outer surface of the housing 100 opposite the front surface 181 will hereinafter also be referred to as fifth surfaces 185 or rear surfaces 185. The outer surfaces of the housing 100 other than the front surface 181 are also outer surfaces of the case 1. That is, the installation surface 182, top surface 183, two side surfaces 184, and rear surface 185 of the outer surface of the housing 100 are also the installation surface 182, top surface 183, two side surfaces 184, and rear surface 185 of the outer surface of the case 1, respectively. Note that the names of the front surface 181, installation surface 182, top surface 183, side surfaces 184, and rear surface 185 are for convenience, and the orientation of the power storage unit 9 when the power storage unit 9 is in use is not limited by these names.

[0017] (3) Case The case 1 is a cylindrical container with a bottom and an opening 10. The case 1 of the first embodiment is rectangular. The outer periphery of the opening 10 is rectangular with rounded corners. The outer periphery of the opening 10 is elongated in one direction, i.e., has two long sides and two short sides. The surface of the outer surface of the case 1 that is aligned along one of the two long sides of the outer periphery of the opening 10 is the installation surface 182, and the surface opposite the installation surface 182, i.e., the surface along the other of the two long sides of the opening 10, is the top surface 183. The surfaces of the outer surface of the case 1 that are aligned along each of the two short sides of the opening 10 are the side surfaces 184. The surface of the outer surface of the case 1 that is opposite the opening 10 is the rear surface 185.

[0018] The case 1 is made of, for example, a resin material such as polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS).

[0019] Each of the two side surfaces 184 of the case 1 has a plurality of cylindrical mounting bosses 19 extending in the direction in which the installation surface 182 and the top surface 183 are aligned. A nut (not shown) is embedded in each mounting boss 19.

[0020] The edge 16 of the opening 10 of the case 1 is formed in a concave shape so as to be able to accommodate a portion of the lid 5 (more specifically, the outer peripheral edge 59 of the lid 5 (see FIG. 5 )). The opening 10 of the case 1 is formed in a rectangular shape with rounded corners. The edge 16 that surrounds the entire periphery of the opening 10 is also formed in a rectangular shape with rounded corners, similar to the opening 10.

[0021] The edge portion 16 includes a first rib 11 positioned to surround the entire opening 10, an outer edge portion 14 located outside the first rib 11, and a second rib 12 located on the outer peripheral edge of the outer edge portion 14 and positioned to surround the entire opening 10 and the first rib 11.

[0022] As shown in Fig. 4 and other figures, the first rib 11 is located at the innermost position of the edge portion 16 and is provided along the edge of the opening 10. In the first embodiment, the first rib 11 forms the edge of the opening 10. The first rib 11 is formed in a rectangular ring shape with rounded corners. The height H1 (see Fig. 10) of the first rib 11 is uniform around the entire circumference.

[0023] The second rib 12 is located at the outermost position of the edge portion 16 and is spaced apart from the first rib 11. The second rib 12 surrounds the opening 10, the first rib 11, and a storage space 71 (described later). The second rib 12 includes dividing ribs 120 located along each of the four sides of the opening 10. The dividing ribs 120 are adjacent to each other at a distance at a corner 141 of the edge portion 16. That is, the second rib 12 is divided at the corner 141 of the edge portion 16. This divided portion of the second rib 12 is referred to as the dividing portion 121, and the dividing portion 121 is also considered a component of the second rib 12. That is, the second rib 12 includes the dividing portion 121 located at the corner 141 of the edge portion 16, and the second rib 12 is locally divided at the dividing portion 121. The height H2 (see FIG. 10) of the second rib 12 is uniform over the entire circumference except for the dividing portion 121.

[0024] The outer edge portion 14 has a rectangular ring shape. The outer edge portion 14 is lower than the first rib 11 and the second rib 12. In other words, the first rib 11 and the second rib 12 are higher than the outer edge portion 14.

[0025] The height H1 of the first rib 11 and the height H2 of the second rib 12 are protrusion dimensions in the direction toward the lid 5 with respect to the case 1 (which can also be said to be the direction toward the opening 10 or the front surface 181 with respect to the rear surface 185) based on a specific portion. The specific portion that serves as the height reference is, for example, the outer edge 14 of the case 1. Note that the specific portion may be any portion that is included in the housing 100 and whose relative position with respect to each of the first rib 11 and the second rib 12 does not change.

[0026] The height H1 of the first rib 11 is equal to or greater than the height H2 of the second rib 12. In the first embodiment, the height H1 of the first rib 11 and the height H2 of the second rib 12 are the same. Alternatively, for example, the height H1 of the first rib 11 may be 3.0 mm and the height H2 of the second rib 12 may be 2.5 mm, so that the first rib 11 is 0.5 mm higher than the second rib 12.

[0027] The edge 16 includes at least one hole 140 through which the fixing member 8 passes. More specifically, a hole 140 is provided at each of the four corners 141 of the outer edge 14.

[0028] The outer edge portion 14 has a storage groove 711 for forming the storage space 71 (see FIG. 4 , etc.). The storage groove 711 has a rectangular shape with rounded corners. The storage groove 711 surrounds the opening 10 and the first rib 11 at a position between the first rib 11 and the second rib 12. In other words, the second rib 12 surrounds the first rib 11 and the storage groove 711 (storage space 71).

[0029] The storage groove 711 is located immediately outside the first rib 11. In other words, there is no gap between the storage groove 711 and the first rib 11. A surface 712 on the opening 10 side of the inner surface of the storage groove 711 and a surface 111 on the opposite side of the opening 10 of the outer surface of the first rib 11 are continuous and aligned flat. There is a gap between the storage groove 711 and the second rib 12. The portion of the outer edge 14 between the storage groove 711 and the second rib 12 is flat, and this portion is aligned flat with the surface of the corner 141. Note that when the outer edge 14 serves as the reference for the heights of the first rib 11 and the second rib 12, the position of the outer edge 14 is the position of the flat portion.

[0030] The edge portion 16 has at least one discharge groove 721 for forming the discharge path 72 on the outer edge portion 14 (see FIG. 4 , etc.). For example, the discharge groove 721 is formed in at least one of the four corners 141. In the first embodiment, two discharge grooves 721 are formed in each of the four corners 141. In each corner 141, the two discharge grooves 721 are positioned to sandwich the hole 140 therebetween. The angle formed by the extension directions of the two discharge grooves 721 that sandwich the hole 140 is approximately a right angle. In other words, the edge portion 16 has a total of eight discharge grooves 721. The eight discharge grooves 721 include discharge grooves 721 extending from the discharge grooves 721 toward the top surface 183 at each of the two corners 141 on both sides of the top surface 183, discharge grooves 721 extending from the discharge grooves 721 toward the side surfaces 184 at each of the two corners 141 on both sides of each side surface 184, and discharge grooves 721 extending from the discharge grooves 721 toward the installation surface 182 at each of the two corners 141 on both sides of the installation surface 182.

[0031] (4) Holder The holder 2 is made of a resin material, such as polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS).

[0032] 4, the holder 2 has five holding portions 21 arranged in one direction to hold the five storage cells 3 arranged parallel to one another. Each holding portion 21 is recessed with a semicircular cross section so that half of a corresponding storage cell 3 fits into it.

[0033] Each holding portion 21 is provided with multiple pairs of claw portions 24. In the first embodiment, each holding portion 21 is provided with three pairs of claw portions 24. Each pair of claw portions 24 elastically clamps the storage cell 3, thereby holding the storage cell 3 in the holding portion 21.

[0034] (5) Storage Cell The storage cell 3 is, for example, an electric double layer capacitor, but may be another type of capacitor such as a lithium ion capacitor.

[0035] The energy storage cell 3 includes an elongated, bottomed, cylindrical container 31 that houses device elements (not shown) and an electrolyte, a sealing body 32 that seals the opening 10 of the container 31, and a positive electrode lead 33 and a negative electrode lead 34 that are drawn out from the sealing body 32. The positive electrode lead 33 is electrically connected to the positive electrode of the device element in the container 31, and the negative electrode lead 34 is electrically connected to the negative electrode of the device element in the container 31.

[0036] (6) Circuit Board The circuit board 4 has a rectangular outer shape. The holder 2 is attached to one surface 41 in the thickness direction of the circuit board 4. When the circuit board 4 and the holder 2 are housed in the case 1 in a predetermined position, the upper part of the circuit board 4 protrudes above the holder 2, and the lower part of the holder 2 protrudes below the circuit board 4.

[0037] The circuit board 4 is provided with pattern wiring for electrically connecting the plurality of storage cells 3 mounted on the holder 2. The positive electrode lead 33 and the negative electrode lead 34 of each storage cell 3 are electrically connected to the pattern arrangement of the circuit board 4 by, for example, soldering.

[0038] The circuit board 4 is further provided with a charging circuit that can charge each storage cell 3 with power supplied from an external power supply source such as a battery. A heat sink 45 for dissipating heat from electrical components such as FETs included in the charging circuit to the outside is attached to one surface 41 of the circuit board 4. The heat sink 45 is attached to a portion of the circuit board 4 that protrudes above the holder 2 when the case 1 is in a predetermined position.

[0039] (7) Lid The lid 5 is made of a resin material, such as polybutylene terephthalate (PBT) or polyphenylene sulfide (PPS).

[0040] The lid 5 is plate-shaped and rectangular. Specifically, the lid 5 has a plate-shaped and rectangular main body 51. The main body 51 includes a front surface 511 and a back surface 512 that face opposite each other in the thickness direction of the main body 51 (see FIGS. 3 and 5). The front surface 511 of the lid 5 faces the side opposite to the side on which the case 1 is located when the lid is fixed. The back surface 512 of the lid 5 faces the side on which the case 1 is located when the lid is fixed. The front surface 511 of the lid 5 is also the front surface 181 (first surface 181) of the housing 100.

[0041] The main body portion 51 includes at least one through-hole 50 through which the fixing member 8 passes. In the first embodiment, each of the four corners of the main body portion 51 has a through-hole 50.

[0042] An inner lid portion 53 that is raised higher than the surrounding area (i.e., outer peripheral edge portion 59, which will be described later) is provided on the back surface 512 of the main body portion 51. The inner lid portion 53 has a shape that corresponds to the shape of the opening 10 of the case 1. In other words, the inner lid portion 53 has a rectangular shape with rounded corners. When the lid 5 is attached to the case 1, the inner lid portion 53 enters the inside of the case 1 through the opening 10 of the case 1.

[0043] The connector 58 includes a housing 581 that is integral with the lid 5, and a plurality of terminals 582 (see FIG. 3). When the lid is fixed, the housing 581 has a rectangular box shape that protrudes toward the side opposite to the side on which the case 1 is located and is open toward the side opposite to the side on which the case 1 is located.

[0044] The multiple terminals 582 are embedded in the bottom of the housing 581 (i.e., part of the main body 51) by, for example, insert molding so as to be aligned in one direction. A first end of each terminal 582 is housed inside the housing 581. A second end of each terminal 582, opposite to the first end, protrudes from the inner lid portion 53 of the lid 5.

[0045] In the first embodiment, the housing 581 of the connector 58 is made of a resin material and is integrally formed with the main body 51 of the lid 5, so there is no structural boundary between the housing 581 and the main body 51 of the lid 5. This prevents liquids such as water from entering.

[0046] Each terminal 582 of the connector 58 of the lid 5 is electrically connected to the pattern wiring of the circuit board 4. This electrically connects the five storage cells 3 to the plurality of terminals 582 that output power from these storage cells 3. In addition, a charging circuit provided on the circuit board 4 is electrically connected to the plurality of terminals 582 that supply external power to this charging circuit.

[0047] 5 , the main body 51 has an outer peripheral edge 59 on the back surface 512, which is positioned further outward than the inner lid portion 53. The outer peripheral edge 59 has a shape that is recessed more than the inner lid portion 53 on the back surface 512 of the lid 5.

[0048] The outer peripheral edge portion 59 includes a recess 54 located outside the inner lid portion 53 and a portion 52 located further outside than the recess 54 .

[0049] The recess 54 is located between the portion 52 of the lid 5 and the inner lid portion 53. The recess 54 is a recessed groove formed in a rectangular ring shape with rounded corners so as to surround the entire circumference of the inner lid portion 53. On the back surface 512 of the main body 51, the inner lid portion 53 protrudes from the inner edge of the bottom surface of the ring-shaped recess 54 (see Figures 9 and 10). The outer portion 52 protrudes from the outer edge of the bottom surface of the recess 54. With the bottom surface of the recess 54 as the base, the inner lid portion 53 protrudes more than the outer portion 52.

[0050] The outer portion 52 of the outer peripheral edge 59 of the lid 5 includes the four corners of the lid 5. That is, the outer portion 52 of the lid 5 includes four through holes 50 through which the fixing members 8 are passed.

[0051] The outer portion 52 of the outer peripheral edge 59 of the lid 5 has a fitting recess 55 on each of the four sides (see FIG. 5). Each fitting recess 55 is formed on each side except for the corners of the lid 5. The fitting recess 55 has a shape such that each side is recessed inward (toward the opening 10) except for the corners.

[0052] (8) Fixing Members The four fixing members 8 are passed through the four through holes 50 of the lid 5, respectively. When the lid 5 is in a position to cover the opening 10 of the case 1, the four through holes 50 of the lid 5 correspond one-to-one to the four holes 140 of the case 1. Of the four holes 140 of the case 1, two holes 140 with cylindrical protrusions 143 around their peripheries communicate with two of the four through holes 50 of the lid 5 that have larger diameters than the others. The protrusions 143 of the two through holes 50 fit into the corresponding larger-diameter through holes 50. This allows the lid 5 to be accurately positioned relative to the case 1.

[0053] The four fixing members 8 are inserted through the four through holes 50 in the lid 5 into the four holes 140 provided in the outer edge 14 of the case 1, thereby fixing the lid 5 in a position that blocks the opening 10 in the case 1.

[0054] In the first embodiment, the fixing member 8 is a fixing screw 8A including a cylindrical threaded portion 81 having a male thread on its outer peripheral surface and a head portion 82 integrally formed at the end of the threaded portion 81 (see FIG. 2 ). The threaded portion 81 of the fixing screw 8A is inserted into a hole 140 in the outer edge portion 14 of the case 1 through a through hole 50 in the lid 5. A female thread is provided on the inner peripheral surface of the hole 140 in the case 1, and the threaded portion 81 of the fixing screw 8A engages with the hole 140, thereby fastening the fixing screw 8A to the hole 140. The head portion 82 of the fixing screw 8A is pressed against the front surface 511 of the lid 5 at the outer portion 52 of the lid 5. In the first embodiment, no female thread is provided on the inner peripheral surface of the through hole 50 in the lid 5, but it is also possible to provide a female thread on the inner peripheral surface of the through hole 50 in the lid 5 that engages with the threaded portion 81 of the fixing screw 8A.

[0055] (9) Lid Fixed State As shown in Fig. 9, in the lid fixed state, the outer portion 52 of the lid 5 fits into the recessed portion formed between the first rib 11 and the second rib 12 of the case 1. The outer portion 52 of the lid 5 is located outward from the first rib 11 and inward from the second rib 12. The outer portion 52 of the lid 5 presses against the recessed portion of the case 1 with pressure. More specifically, the outer portion 52 of the lid 5 comes into surface contact with pressure against the outer edge portion 14 provided between the first rib 11 and the second rib 12 of the case 1. The surface of the outer portion 52 of the lid 5 that contacts the outer edge portion 14 is flat.

[0056] The surface of outer portion 52 of lid 5 entirely closes opening 10 of storage groove 711 at outer edge 14. This closes the space inside storage groove 711, and this space inside storage groove 711 forms storage space 71. As a result, housing 100 has storage space 71 sandwiched between edge 16 of opening 10 of case 1 and lid 5. Storage space 71 is a rectangular ring shape that surrounds opening 10.

[0057] The surface of outer portion 52 of lid 5 also entirely closes opening 10 of discharge groove 721 at outer edge 14. As a result, the space inside discharge groove 721 forms discharge path 72. As a result, housing 100 has discharge path 72 sandwiched between edge 16 of opening 10 of case 1 and lid 5. Discharge path 72 connects storage space 71 to the outside of housing 100.

[0058] In the first embodiment, the edge 16 of the case 1 has two discharge grooves 721 at each corner 141 of the outer edge 14 (see FIG. 4 ). Therefore, the housing 100 has discharge channels 72 at positions corresponding to the corners 181A of the rectangular front face 181. In the first embodiment, the edge 16 of the case 1 has two discharge grooves 721 at each of the four corners 141 of the outer edge 14. Therefore, the housing 100 has two discharge channels 72 at positions corresponding to the four corners 181A of the rectangular front face 181. In other words, the housing 100 has eight discharge channels 72. The angles formed by the directions in which the two discharge grooves 721 extend at positions corresponding to the corners 181A of the front face 181 are approximately right angles. The eight discharge paths 72 include discharge paths 72 that extend from the storage space 71 toward the upper surface 183 at positions corresponding to each of the two corners 181A on the upper surface 183 side and open at the upper surface 183. The eight discharge paths 72 also include discharge paths 72 that extend from the storage space 71 toward the side surface 184 at positions corresponding to each of the two corners 181A on each of the side surfaces 184 and open at the side surfaces 184. The eight discharge paths 72 also include discharge paths 72 that extend from the storage space 71 toward the installation surface 182 at positions corresponding to each of the two corners 181A on the installation surface 182 side and open at the installation surface 182 (see FIGS. 4, 6, 7, and 8).

[0059] In the first embodiment, the minimum area of ​​the cross section perpendicular to the direction in which the discharge passage 72 extends is smaller than the minimum area of ​​the cross section perpendicular to the direction in which the storage space 71 extends.

[0060] In the lid fixed state, the first rib 11 surrounds the opening 10 inside the storage space 71, and the second rib 12 surrounds the opening 10, the first rib 11, and the storage space 71. In the lid fixed state, a portion 52 located outside the recess 54 in the outer peripheral edge 59 of the lid 5 is inserted between the first rib 11 and the second rib 12.

[0061] The second rib 12 is arranged to surround the outer periphery of the lid 5 along the outer peripheral edge 521 of the outer portion 52 of the lid 5. There is a one-to-one correspondence between the four dividing ribs 120 of the second rib 12 and the four fitting recesses 55 in the outer portion 52 of the lid 5. When the lid is fixed, each dividing rib 120 fits into the corresponding fitting recess 55.

[0062] The end 521 of the lid 5 is the outermost end of the lid 5 and is the end closest to the second rib 12. In the lid fixed state, the outer peripheral surface of the end 521 of the lid 5 faces the second rib 12.

[0063] In the lid fixed state, the height H1 of the first rib 11 of the case 1 is equal to or greater than the height H5 of the end 521 of the lid 5. Furthermore, the height H2 of the second rib 12 of the case 1 is equal to or greater than the height H5 of the end 521 of the lid 5. In other words, the height H5 of the end 521 of the lid 5 is the height of the outer circumferential surface of the end 521. In the first embodiment, the first rib 11 of the case 1 is higher than the end 521 of the lid 5, and the second rib 12 of the case 1 is higher than the end 521 of the lid 5. The height H5 of the end 521 of the lid 5 may be the same as the height H2 of the second rib 12.

[0064] (10) Method for Manufacturing the Energy Storage Unit 9 The method for manufacturing the energy storage unit 9 according to the first embodiment includes an accommodating step and a fixing step.

[0065] In the accommodation step, the holder 2 holding at least one storage cell 3 is accommodated in the case 1 having an opening 10 through the opening 10. More specifically, the holder 2 holding five storage cells 3, the circuit board 4, and the lid 5 are integrated together, and then the holder 2 holding the five storage cells 3 and the circuit board 4 are accommodated in the case 1 through the opening 10. The opening 10 of the case 1 is closed with the lid 5.

[0066] In the fixing process, with the opening 10 of the case 1 closed by the lid 5, the lid 5 is fixed to the case 1 using four fixing members 8. At this time, the annular outer portion 52 included in the lid 5 fits between the annular first rib 11 and the annular second rib 12 included in the case 1. The outer portion 52 of the lid 5 comes into surface contact with the outer edge portion 14 of the case 1, which is provided with holes 140 for fastening the fixing members 8, due to pressure generated by fastening the fixing members 8. The annular first rib 11 included in the case 1 fits into an annular recess 54 formed inside the outer portion 52 included in the lid 5.

[0067] (11) Effects of the Embodiments In the energy storage unit 9 of the first embodiment, as described below, the intrusion of liquids such as water into the energy storage unit 9 from between the case 1 and the lid 5 in the housing 100 is effectively prevented.

[0068] First, height H2 of second rib 12 is equal to or greater than height H5 of end 521 of portion 52 of lid 5. This prevents liquid from seeping into the gap between outermost portion 52 of lid 5 and second rib 12 located on the outermost periphery of case 1. Even if liquid seeps into the gap, portion 52 of lid 5 and outer edge 14 of case 1 are in surface contact with pressure, so the liquid is prevented from seeping inward through the gap.

[0069] Furthermore, the housing 100 has a storage space 71 and a drain path 72 sandwiched between the edge 16 of the opening 10 of the case 1 and the lid 5, the storage space 71 being annular and surrounding the opening 10, and the drain path 72 connecting the storage space 71 to the outside of the housing 100. Therefore, even if a liquid such as water seeps into the space between the case 1 and the lid 5 of the housing 100, the liquid reaches the storage space 71 before reaching the opening 10 and is stored in the storage space 71. The liquid in the storage space 71 can be drained to the outside of the housing 100 through the drain path 72. This makes it difficult for the liquid to reach the opening 10, and the liquid is prevented from seeping into the electricity storage unit 9.

[0070] It is preferable that the liquid stored in the storage space 71 flows preferentially to the discharge path 72 rather than from the storage space 71 to between the case 1 and the lid 5 on the opening 10 side, that is, between the outer surface of the first rib 11 and the inner surface of the recess 54. For this reason, it is preferable that the clearance from the storage space 71 between the case 1 and the lid 5 on the opening 10 side and the dimensions of the discharge path 72 are appropriately adjusted.

[0071] Because the minimum area of ​​the cross section perpendicular to the direction in which the discharge path 72 extends is smaller than the minimum area of ​​the cross section perpendicular to the direction in which the storage space 71 extends, liquid is less likely to seep into the discharge path 72 from outside the housing 100. Even if liquid does seep into the discharge path 72 from outside the housing 100, the amount of liquid that seeps in is small relative to the size of the storage space 71, and therefore the liquid can be sufficiently stored in the storage space 71. This can further suppress the liquid from seeping into the electricity storage unit 9.

[0072] The liquid in the storage space 71 tends to accumulate in a position within the storage space 71 that corresponds to the corner 181A of the front surface 181. For example, if the power storage unit 9 is placed in an orientation in which the installation surface 182 faces downward, and the power storage unit 9 is tilted slightly, the liquid in the storage space 71 tends to accumulate in a position that corresponds to the corner 181A on the installation surface 182 side. However, because the discharge path 72 is located in a position that corresponds to the corner 181A of the front surface 181, the liquid that has accumulated in the storage space 71 can be discharged from the discharge path 72 to the outside of the housing 100. This can further suppress the intrusion of liquid into the power storage unit 9.

[0073] Furthermore, the presence of the first rib 11 further inward from the storage space 71 prevents the liquid from seeping into the opening 10 of the case 1. In particular, in the first embodiment, the height H1 of the first rib 11 is equal to or greater than the height H2 of the second rib 12, so the liquid can overflow beyond the second rib 12 and outside before it passes beyond the first rib 11 and seeps into the case 1. This can further prevent the liquid from seeping into the electricity storage unit 9.

[0074] Furthermore, the surface 712 on the opening 10 side of the inner surface of the storage space 71 and the surface 111 on the opposite side from the opening 10 of the outer surface of the first rib 11 are continuous and evenly aligned. Therefore, in order for the liquid accumulated in the storage space 71 to exceed the first rib 11, it must overcome the surface on the opening 10 side of the inner surface of the storage space 71 and the surface 111 on the opposite side from the opening 10 of the outer surface of the first rib 11, which lengthens the path the liquid must travel. This effectively prevents the liquid accumulated in the storage space 71 from moving toward the opening 10. This can further prevent the liquid from seeping into the electricity storage unit 9.

[0075] Furthermore, the second rib 12 is disposed to surround the outer periphery of the lid 5. However, even if liquid adheres to the front surface 181 of the housing 100, the second rib 12 is locally separated at the separating portion 121. Therefore, the liquid easily flows out of the front surface 511 of the lid 5 (the front surface 181 of the housing) through the separating portion 121. This can prevent liquid adhering to the lid 5 from seeping in between the second rib 12 and the outer periphery of the lid 5. This can further prevent liquid from seeping into the power storage unit 9. Furthermore, liquid adhering to the lid 5 easily collects at the corners 181A of the front surface 181. For example, if the power storage unit 9 is placed with the installation surface 182 facing downward and the power storage unit 9 is tilted slightly, the liquid adhering to the front surface 181 easily collects at the corners 181A on the installation surface 182 side. However, particularly in the first embodiment, the second rib 12 is separated by the separating portion 121 at the corner portion 181A of the front surface 181, and therefore the liquid adhering to the front surface 181 can easily flow out from the separating portion 121 to the outside of the front surface 181. This can further suppress the intrusion of the liquid into the electricity storage unit 9.

[0076] The power storage unit 9 is mounted inside a mobile object such as an automobile. In this case, for example, the power storage unit 9 is placed on a substrate or the like with the installation surface 182 facing downward. In this state, fixing members such as screws or bolts are inserted into the mounting bosses 19, and the power storage unit 9 is fixed to the substrate or the like by the fixing members.

[0077] However, the orientation of the power storage unit 9 when it is used is not limited to the above. For example, the power storage unit 9 may be used in an orientation in which the front surface 181 faces upward, or in an orientation in which the front surface 181 faces downward.

[0078] According to the first embodiment, the intrusion of liquid into the case 1 can be prevented without placing a gasket between the lid 5 and the case 1, which contributes to simplifying the configuration of the storage unit 9 and also contributes to reducing the labor required to assemble the storage unit 9.

[0079] 3. Second Embodiment The second embodiment has the same configuration as the first embodiment except for the configuration of the discharge groove 721 and the discharge path 72. In the following, the description of the same configuration as the first embodiment will be omitted as appropriate.

[0080] In the second embodiment, as described below, the discharge path 72 does not open to the third surface 183 (upper surface 183).

[0081] As in the first embodiment, the edge portion 16 of the case 1 has discharge grooves 721 at the outer edge portion 14 to form the discharge path 72. In the second embodiment, of the four corners 141 of the outer edge portion 14, discharge grooves 721 are formed only at two corners 141 on the installation surface 182 side. Two discharge grooves 721 are formed at each of these two corners 141. At each of these two corners 141, the two discharge grooves 721 are positioned to sandwich a hole 140 therebetween. The angle formed by the extension directions of the two discharge grooves 721 that sandwich the hole 140 is approximately a right angle. In other words, the edge portion 16 has a total of four discharge grooves 721. The four discharge grooves 721 include a discharge groove 721 extending from the discharge groove 721 toward the side surface 184 at the corner 141 on the installation surface 182 side of the two corners 141 on each side surface 184, and a discharge groove 721 extending from the discharge groove 721 toward the installation surface 182 at each of the two corners 141 on the installation surface 182 side (see Figure 11).

[0082] In the lid fixed state, the housing 100 has discharge channels 72 at positions corresponding to two of the four corners 181A of the rectangular front surface 181 that are on the installation surface 182 side. That is, the housing 100 has four discharge channels 72. The angles formed by the extension directions of the two discharge grooves 721 at the positions corresponding to each of the two corners 181A are approximately right angles. The four discharge channels 72 include discharge channels 72 that extend from the storage space 71 toward the side surface 184 at positions corresponding to the corners 181A on the installation surface 182 side of the two corners 181A on each side surface 184, and discharge channels 72 that extend from the storage space 71 toward the installation surface 182 at positions corresponding to each of the two corners 181A on the installation surface 182 side.

[0083] In the second embodiment, as in the first embodiment, the intrusion of liquid such as water into the power storage unit 9 from between the case 1 and the lid 5 in the housing 100 is effectively prevented.

[0084] Furthermore, as described above, in the second embodiment, the drain path 72 does not open on the third surface 183 (top surface 183). Therefore, even if the third surface 183 is frequently exposed to liquid such as water, liquid is unlikely to infiltrate into the drain path 72. For example, when the power storage unit 9 is placed with the installation surface 182 facing downward and the top surface 183 facing upward, even if liquid falls onto the power storage unit 9 from above and adheres to the top surface 183 of the power storage unit 9, the liquid is unlikely to infiltrate into the drain path 72. Therefore, when the power storage unit 9 is used such that the third surface 183 is placed in a position that is frequently exposed to liquid such as water, the infiltration of liquid into the power storage unit 9 can be further suppressed.

[0085] Furthermore, in the second embodiment, the drain channel 72 does not open on the side surface 184 at a position corresponding to the corner 181A on the top surface 183 side, out of the two corners 181A of each side surface 184. Therefore, even if liquid adhering to the top surface 183 flows onto the side surface 184, the liquid is less likely to seep into the drain channel 72. This can further prevent the liquid from seeping into the electricity storage unit 9.

[0086] Furthermore, in the second embodiment, as described above, the housing 100 has the drain channels 72 at positions corresponding to the two corners 181A on the installation surface 182 side. Therefore, liquid in the storage space 71 can be easily drained through the drain channels 72. For example, when the power storage unit 9 is placed with the installation surface 182 facing downward, the liquid in the storage space 71 tends to accumulate unevenly on the installation surface 182 side. Furthermore, when the power storage unit 9 is slightly tilted, the liquid in the storage space 71 tends to accumulate at positions corresponding to the corners 181A on the installation surface 182 side. However, when the drain channels 72 are provided at positions corresponding to the two corners 181A on the installation surface 182 side, the liquid accumulated in the storage space 71 can be easily drained through the drain channels 72 to the outside of the housing 100. Therefore, the infiltration of liquid into the power storage unit 9 can be further suppressed.

[0087] 4. Modifications The above-described first and second embodiments are merely a part of various embodiments of the present disclosure. The above-described first and second embodiments can be modified in various ways depending on the design, etc., as in the modifications listed below, as long as the object of the present disclosure can be achieved. In the following description of the modifications, detailed description of configurations similar to those of the above-described first and second embodiments will be omitted.

[0088] In the first and second embodiments, the storage space 71 is defined by the annular storage groove 711 of the case 1, but the storage space 71 is not limited to the configuration in the first and second embodiments as long as it is sandwiched between the edge 16 of the opening 10 of the case 1 and the lid 5 and has an annular shape surrounding the opening 10. For example, the case 1 may not have the storage groove 711, and the lid 5 may have an annular groove similar to the storage groove 711, and this groove may define the storage space 71. The case 1 may have the storage groove 711, and the lid 5 may also have an annular groove, and the storage space 71 may be defined by the storage groove 711 of the case 1 and the annular groove of the lid 5.

[0089] In the first and second embodiments, the drainage channel is formed by a drainage groove in the case 1, and the drainage channel opens on any of the top surface 183, the installation surface 182, and the side surface 184. However, the drainage channel is not limited to the configurations in the first and second embodiments as long as it is sandwiched between the edge 16 of the opening 10 in the case 1 and the lid 5 and connects the storage space 71 to the outside of the housing 100. For example, the case 1 may not have a drainage groove, and the lid 5 may have a groove similar to the drainage groove, and this groove may form the drainage channel. The case 1 may have a drainage groove, and the lid 5 may also have a similar groove, and the drainage channel may be formed by the drainage groove of the case 1 and the groove of the lid 5.

[0090] Furthermore, the shapes of the housing 100, the opening 10, and the lid 5 are not limited to those of the first and second embodiments, and the housing 100, the opening 10, and the lid 5 may have any suitable shapes. The number and positions of the drainage channels in the housing 100 are not limited to those of the first and second embodiments, and the housing 100 may have any suitable number of drainage channels at any suitable positions sandwiched between the edge 16 of the opening 10 in the case 1 and the lid 5.

[0091] In the first and second embodiments, the case 1 has the first rib 11 and the second rib 12, but the case 1 does not have to have one or both of the first rib 11 and the second rib 12. When the case 1 has the first rib 11 and the second rib 12, the height H1 of the first rib 11 may be less than the height H2 of the second rib 12.

[0092] In the first and second embodiments described above, the second rib 12 of the case 1 is locally divided, but the configuration of the second rib 12 is not limited to this. In other words, the second rib 12 may surround the opening 10 and the first rib 11 of the case 1 over the entire periphery without being divided.

[0093] In the first and second embodiments described above, the outer portion 52 of the lid 5 is in contact with the outer edge 14 of the case 1, but it is also possible to position the two 52, 14, for example, with a small gap between them, so that the two 52, 14 are not in contact with each other.

[0094] In the first and second embodiments described above, fixing screws 8A are used as the fixing members 8, but the type of fixing member 8 is not limited to this. Bolts can also be used as the fixing members 8. In this case, it is preferable to provide nuts on the outer edge 14 of the case 1 to fasten the bolts to. Rivets can also be used as the fixing members 8. Any type of rivet can be used as the rivet, as long as it can be inserted into the hole 140 in the case 1 and hook onto the case 1.

[0095] Furthermore, in the first and second embodiments described above, the lid 5 and the housing 581 of the connector 58 are integrally formed, but this is not limiting, and the lid 5 and the housing 581 of the connector 58 may be provided separately. In this case, it is preferable to join the lid 5 and the housing 581, which are provided separately from each other, by an appropriate means.

[0096] Also, instead of providing the first rib 11 and the second rib 12 on the case 1, two types of ribs may be provided on the lid 5 for the purpose of preventing liquid from entering.

[0097] [Aspects] As is apparent from the above embodiment, the present disclosure includes the following aspects.

[0098] The energy storage unit (9) of the first aspect includes a housing (100) and an energy storage cell (3) housed in the housing (100). The housing (100) includes a case (1) having an opening (10) and a lid (5) fixed to the case (1) so as to close the opening (10). The housing (100) has a storage space (71) and a discharge path (72) sandwiched between an edge (16) of the opening (10) of the case (1) and the lid (5). The storage space (71) is annular and surrounds the opening (10). The discharge path (72) connects the storage space (71) to the outside of the housing (100).

[0099] According to this embodiment, even if liquid attempts to enter the housing (100) from between the case (1) and the lid (5) of the housing (100), the liquid is stored in the storage space (71) and can be discharged from the storage space (71) to the outside of the housing (100) through the discharge path (72). Therefore, the liquid can be prevented from entering the electricity storage unit (9) from between the lid (5) and the case (1) of the electricity storage unit (9).

[0100] In the second aspect, the minimum area of ​​the cross section perpendicular to the direction in which the discharge passage (72) extends is smaller than the minimum area of ​​the cross section perpendicular to the direction in which the storage space (71) extends.

[0101] According to this embodiment, even if liquid seeps into the discharge path (72) from outside the housing (100), the amount of the liquid that seeps in is small relative to the size of the storage space (71), and therefore the liquid can be sufficiently stored in the storage space (71). This can further suppress the liquid from seeping into the electricity storage unit (9).

[0102] In the third aspect, the housing (100) of the first or second aspect has a rectangular surface (first surface (181)) on the side closer to the lid (5). The discharge path 72 is located at a position corresponding to a corner (181A) of the rectangular surface (first surface (181)).

[0103] According to this embodiment, liquid that has accumulated in the storage space (71) at a position corresponding to the corner portion (181A) can be easily discharged through the discharge path (72).

[0104] In a fourth aspect, in any one of the first to third aspects, the housing (100) has a first surface (181) that is a rectangular surface located closer to the lid (5), a second surface (182) along one side of the first surface (181), and a third surface (183) opposite the second surface (182). The discharge channel (72) is not open on the second surface (182).

[0105] According to this embodiment, even if the third surface (183) is frequently exposed to liquid, the liquid is less likely to infiltrate into the discharge path (72).

[0106] In a fifth aspect, in any one of the first to fourth aspects, the edge portion (16) of the case (1) has a first rib (11) that surrounds the opening (10) inside the storage space (71) and a second rib (12) that surrounds the opening (10), the first rib (11), and the storage space (71). The height (H1) of the first rib (11) is equal to or greater than the height (H2) of the second rib (12). The lid (5) has a portion (52) that fits between the first rib (11) and the second rib (12) when the lid (5) is fixed to the case (1).

[0107] According to this aspect, the presence of the first rib (11) and the second rib (12) of the case (1) can further prevent liquids such as water from entering the case (1).

[0108] In the sixth aspect, in the fifth aspect, the surface (712) on the inner surface of the storage space (71) closer to the opening (10) and the surface (111) on the outer surface of the first rib (11) opposite the opening (10) are continuous and flat.

[0109] According to this embodiment, the first rib (11) can effectively prevent the liquid in the storage space (71) from moving toward the opening (10).

[0110] In the seventh aspect, in the fifth or sixth aspect, the second rib (12) is arranged so as to surround the outer periphery of the lid (5) and is locally divided.

[0111] According to this aspect, liquid adhering to the lid (5) can flow out from the portion where the second rib (12) is separated, and therefore the liquid is less likely to remain on the lid (5), which can further prevent liquid from entering the electricity storage unit (9) through the gap between the lid (5) and the case (1).

[0112] In an eighth aspect, in any one of the first to seventh aspects, a connector (58) is further provided which includes a housing (581) integral with the lid (5) and a terminal (583) electrically connected to the storage cell (3).

[0113] According to this aspect, there is no structural boundary between the housing (581) of the connector (58) and the lid (5), so that liquid is more effectively prevented from penetrating into the case (1).

[0114] REFERENCE SIGNS LIST 1 Case 10 Opening 100 Housing 11 First rib 12 Second rib 16 Edge 181 First surface (front surface) 181A Corner of first surface 182 Second surface (installation surface) 183 Third surface (top surface) 184 Fourth surface (side surface) 3 Energy storage cell 5 Lid 52 Part 58 Connector 581 Housing 71 Storage space 72 Discharge path 9 Energy storage unit H1 Height of first rib H2 Height of second rib

Claims

1. An energy storage unit comprising: a housing; and energy storage cells housed in the housing; the housing comprising: a case having an opening; and a lid fixed to the case so as to close the opening; the housing having a storage space and a discharge path sandwiched between an edge of the opening of the case and the lid; the storage space being annular and surrounding the opening; and the discharge path connecting the storage space to the outside of the housing.

2. The electricity storage unit according to claim 1, wherein the minimum area of ​​a cross section perpendicular to the direction in which the discharge passage extends is smaller than the minimum area of ​​a cross section perpendicular to the direction in which the storage space extends.

3. The energy storage unit according to claim 1, wherein the housing has a rectangular surface on a side closer to the lid, and the discharge channel is located at a position corresponding to a corner of the rectangular surface.

4. The energy storage unit according to claim 1, wherein the housing has a first surface which is a rectangular surface located closer to the lid, a second surface along one side of the first surface, and a third surface opposite the second surface, and the discharge path does not open on the third surface.

5. The energy storage unit according to claim 1, wherein the edge of the case has a first rib that surrounds the opening inside the storage space, and a second rib that surrounds the opening, the first rib, and the storage space, the protruding height of the first rib is equal to or greater than the protruding height of the second rib, and the lid has a portion that fits between the first rib and the second rib when the lid is fixed to the case.

6. The electricity storage unit according to claim 5, wherein a surface of the inner surface of the storage space that is closer to the opening and a surface of the outer surface of the first rib that is opposite to the opening are continuous and flat.

7. The energy storage unit according to claim 5, wherein the second rib is arranged so as to surround the outer periphery of the lid and is locally divided.

8. The energy storage unit according to claim 1, further comprising a connector having a housing integral with the lid and a terminal electrically connected to the energy storage cell.

Images