Energy storage apparatus

An energy storage apparatus including: an energy storage device; an outer covering; electric equipment disposed in the outer covering; and a housing part which houses the electric equipment, wherein a drain passage, which is disposed in a region covered by the electric equipment and through which water is discharged to outside of the region, is formed on a lower wall surface below the electric equipment in the housing part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese patent applications No. 2015-186042, filed on Sep. 18, 2015, and No. 2015-186051, filed on Sep. 18, 2015, which are incorporated by reference.

FIELD

The present invention relates to an energy storage apparatus provided with an energy storage device and an outer covering.

BACKGROUND

Conventionally, there has been known an energy storage apparatus which houses a plurality of energy storage devices therein. In an outer covering, electric equipment such as a printed circuit board which performs an electric control of the energy storage apparatus is also housed (see JP-2015-11956A, for example).

During the use of an energy storage apparatus, due to a difference in temperature between the inside and outside of an outer covering, there may be a case where dew condensation occurs in the outer covering. In this case, there is a possibility that the condensed dew touches electric equipment and short-circuiting of the electric equipment occurs.

SUMMARY

An object of the present invention to provide an energy storage apparatus which can suppress short-circuiting of electric equipment caused by condensed dew generated in an outer covering.

According to an aspect of the present invention, there is provided an energy storage apparatus which includes: an energy storage device; an outer covering; electric equipment disposed in the outer covering; and a housing part which houses the electric equipment, wherein a drain passage, which is disposed in a region covered by the electric equipment and through which water is discharged to outside of the region, is formed on a wall surface below the electric equipment in the housing part.

DESCRIPTION OF EMBODIMENTS

According to an aspect of the present invention, there is provided an energy storage apparatus which includes: an energy storage device; an outer covering; electric equipment disposed in the outer covering; and a housing part which houses the electric equipment, wherein a drain passage, which is disposed in a region covered by the electric equipment and through which water is discharged to outside of the region, is formed on a wall surface below the electric equipment in the housing part.

With such a configuration, the drain passage through which water is discharged to the outside of the region covered by the electric equipment is formed on the wall surface below the electric equipment in the housing part and hence, it is possible to suppress accumulation of condensed dew on a lower side of the electric equipment. Accordingly, it is possible to suppress short-circuiting of the electric equipment caused by dew condensation.

The drain passage may have a first inclined surface which is gradually lowered as the drain passage extends toward a drain port of the drain passage.

With such a configuration, the drain passage has the first inclined surface which is gradually lowered as the drain passage extends toward the drain port. Accordingly, drain water can be guided to the drain port by the first inclined surface with certainty.

A conductive member may be disposed at a position away from an area vertically below the drain port in a horizontal direction.

With such a configuration, the conductive member is disposed at the position away from the area vertically below the drain port in the horizontal direction and hence, drain water can be prevented from falling onto the conductive member. Accordingly, it is possible to prevent short-circuiting of the energy storage apparatus per se by drain water.

A second inclined surface, which is lowered as the second inclined surface extends toward the first inclined surface, may be formed in the region.

With such a configuration, the second inclined surface which is lowered as the second inclined surface extends toward the first inclined surface of the drain passage is formed in the region covered by the electric equipment. Accordingly, the dew condensation generated in the region can be guided to the first inclined surface by the second inclined surface.

An elongated projecting portion or a groove portion may be formed on the second inclined surface along an inclination direction.

With such a configuration, the elongated projecting portion is formed on the second inclined surface along the inclination direction. Accordingly, the condensed dew can be easily merged as liquid droplets and, at the same time, the liquid droplets can be guided to the first inclined surface by the projecting portion.

The electric equipment may be disposed in a spaced-apart manner from the wall surface.

With such a configuration, the electric equipment is disposed in a spaced-apart manner from the wall surface which is disposed below the electric equipment. Accordingly, it is possible to prevent the electric equipment from being brought into contact with the condensed dew generated on the wall surface.

The wall surface may be a hydrophobic surface.

With such a configuration, the wall surface disposed below the electric equipment is a hydrophobic surface. Accordingly, it is possible to accelerate the flow of condensed dew generated on the wall surface.

According to one aspect of the present invention, there is provided an energy storage apparatus which includes: an energy storage device; an outer covering; electric equipment disposed in the outer covering; and a housing part which houses the electric equipment, wherein a first inclined portion which is disposed in a region which covers the electric equipment and is disposed closer to the electric equipment as the first inclined portion approaches an edge of the region is formed on an upper wall surface of the housing part above the electric equipment.

With such a configuration, the first inclined portion which is disposed closer to the electric equipment as the first inclined portion approaches the edge of the region is formed on the region of an upper wall surface of the housing part which covers the electric equipment. Accordingly, it is possible to guide the condensed dew to a desired position using the first inclined portion as a guide. Accordingly, it is possible to suppress falling of condensed dew on the electric equipment and hence, short-circuiting of the electric equipment can be suppressed.

The first inclined portion is continuously formed from the region to an outer region disposed adjacently to the region, and an outer region side of the first inclined portion may be set lower than a region side of the first inclined portion.

With such a configuration, the first inclined portion is continuously formed to the outer region and hence, it is possible to guide the condensed dew to the outside of the electric equipment. Accordingly, it is possible to suppress falling of condensed dew on the electric equipment more effectively.

The first inclined portion is a projecting portion which projects toward an electric equipment side from the upper wall surface, and the projecting portion may be formed in an elongated manner along the upper wall surface.

With such a configuration, the first inclined portion is formed of the elongated projecting portion. Accordingly, compared to a case where the upper wall surface is simply inclined, condensed dew is minimally fallen and hence, condensed dew can be easily merged as liquid droplets.

The first inclined portion may be formed of a plurality of first inclined portions which are disposed at intervals.

With such a configuration, the plurality of first inclined portions are disposed at intervals. Accordingly, the condensed dew can be guided in a wide range.

A second inclined portion which is disposed closer to the electric equipment as the second inclined portion extends toward the first inclined portion may be formed on the upper wall surface.

With such a configuration, the second inclined portion which is disposed closer to the electric equipment as the second inclined portion extends toward the first inclined portion is formed on the upper wall surface. Accordingly, the condensed dew can be guided to the first inclined portion by the second inclined portion. Therefore, the condensed dew can be easily guided to the first inclined portion.

The first inclined portion may be formed of an inclined surface formed by inclining at least a portion of the upper wall surface.

With such a configuration, the first inclined surface is formed of the inclined surface. Accordingly, it is possible to guide the condensed dew to a desired position with the simple configuration.

The upper wall surface may be a hydrophilic surface.

With such a configuration, the upper wall surface is a hydrophilic surface. Accordingly, it is possible to suppress falling of the condensed dew generated on the upper wall surface.

According to the energy storage apparatus of the present invention, it is possible to suppress the short-circuiting of the electric equipment caused by condensed dew which is generated in the outer covering.

Hereinafter, an energy storage apparatus according to an embodiment of the present invention is described with reference to drawings. The embodiment described hereinafter is one preferred specific example of the present invention. In the embodiment described hereinafter, numerical values, shapes, materials, constitutional elements, the arrangement positions and connection states of the constitutional elements and the like are merely examples, and these are not intended to limit the present invention. Further, out of the constitutional elements in the embodiment described hereinafter, the constitutional elements which are not described in independent claims describing an uppermost concept are described as arbitrary constitutional elements. In the respective drawings, the respective constitutional elements are not described strictly accurately in size or the like.

Embodiment

First, a configuration of an energy storage apparatus1is described.

FIG. 1is a perspective view showing an external appearance of an energy storage apparatus1according to an embodiment of the present invention.FIG. 2is an exploded perspective view showing constitutional elements of the energy storage apparatus1.

In these drawings, the Z axis direction is indicated as the vertical direction, and the description is made hereinafter using the Z axis direction as the vertical direction. However, there may be also a case where the Z axis direction is not the vertical direction depending on a mode of use. Accordingly, the Z axis direction is not limited to the vertical direction. The same goes for drawings which are referenced hereinafter.

The energy storage apparatus1is an apparatus which can charge electricity from the outside of the energy storage apparatus1therein or can discharge electricity to the outside of the energy storage apparatus1. For example, the energy storage apparatus1may be a battery module used for power storage application, power source application or the like. It is preferable that the energy storage apparatus1according to this embodiment be used as a starting battery for a mobile body such as an automobile or a two-wheeled vehicle. There may be a case where the energy storage apparatus1is installed in a hood of a mobile body or in a trunk in a state where an outer covering10is exposed to the outside. The energy storage apparatus1may be used in a single form (single body) without being connected with other energy storage apparatus (battery module). For example, with respect to a mobile body (truck or the like) which requires a large power consumption at the time of starting, there may be a case where a plurality of energy storage apparatuses1are connected to each other in series. In this case, the plurality of energy storage apparatuses1are not used in an integrated manner but used in a single form (single body) respectively. That is, the energy storage apparatus1of this embodiment may differ from a so-called battery pack where a plurality of energy storage apparatuses are housed in a case and are integrated with each other.

As shown inFIG. 1andFIG. 2, the energy storage apparatus1includes: an outer covering10formed of a first outer covering11and a second outer covering12; and an energy storage unit20, a holder30, bus bars41,42, thermistors50and the like which are housed in the outer covering10.

The outer covering10is a container (module case) having a rectangular shape (box shape) which forms an outer covering of the energy storage apparatus1. Only a part of the outer covering10is communicated with the outside so that the energy storage apparatus1is used substantially in a sealed state (almost in a sealed state). The outer covering10is disposed outside the energy storage unit20, the holder30, the bus bars41,42and the thermistors50and allows the energy storage unit20and the like to be disposed at predetermined positions in the outer covering10thus protecting the energy storage unit20and the like from an impact or the like. For example, the outer covering10is made of an insulating resin material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), a polyphenylene sulfide resin (PPS), polybutylene terephthalate (PBT) or an ABS resin. The outer covering10prevents the energy storage unit20and the like from coming into contact with a metal member or the like disposed outside the outer covering10.

The outer covering10includes: the first outer covering11forming a lid body of the outer covering10; and the second outer covering12forming a body of the outer covering10. The first outer covering11is a cover member having a flat rectangular shape which closes an opening of the second outer covering12. A positive electrode external terminal13and a negative electrode external terminal14are mounted on the first outer covering11. The energy storage apparatus1charges electricity from the outside therein or discharges electricity to the outside through the positive electrode external terminal13and the negative electrode external terminal14. The second outer covering12is a bottomed rectangular cylindrical case having the opening. The second outer covering12houses the energy storage unit20, the holder30, the bus bars41,42, the thermistors50and the like.

The first outer covering11and the second outer covering12may be made of the same material, or may be made of different materials.

The detailed configuration of the first outer covering11is described later.

The energy storage unit20includes a plurality of energy storage devices100(twelve energy storage devices100in this embodiment) and a plurality of bus bars200, and is electrically connected to the positive electrode external terminal13and the negative electrode external terminal14formed on the first outer covering11. A positive electrode terminal of any one of the plurality of energy storage devices100is electrically connected to the positive electrode external terminal13through the bus bar200. A negative electrode terminal of any one of the plurality of energy storage devices100is electrically connected to the negative electrode external terminal14through the bus bar200.

The energy storage unit20is disposed in the second outer covering12such that the plurality of energy storage devices100are arranged in a row in the X axis direction in a state where each energy storage device100is mounted vertically (in a state where a positive electrode terminal and a negative electrode terminal are directed upward). The energy storage unit20is housed in the outer covering10while being covered by the first outer covering11from above. The detailed description of the configuration of the energy storage unit20is made later.

The holder30is a member which holds the bus bars41,42, can provide insulation between the bus bars41,42and other members, and can perform positional regulation of the bus bars41,42. The holder30positions the bus bars41,42with respect to the bus bars200in the energy storage unit20, and the positive electrode external terminal13and the negative electrode external terminal14.

The holder30is disposed on an upper side of the energy storage unit20(a plus side in the Z axis direction), and is positioned with respect to the energy storage unit20. The holder30is positioned by disposing the bus bars41,42on the holder30. The first outer covering11is disposed on the holder30. With such a configuration, the bus bars41,42are positioned with respect to the bus bars200disposed in the energy storage unit20, and the positive electrode external terminal13and the negative electrode external terminal14which are mounted on the first outer covering11.

The holder30also has a function of holding the thermistors50. That is, by mounting the thermistors50on the holder30, the thermistors50are positioned with respect to the energy storage devices100, and are fixed in a state where the thermistors50are pressed to the energy storage devices100.

Although the holder30is made of an insulating resin material such as PC, PP, PE, PPS, PBT or an ABS resin, the holder30may be made of any material as long as a material has an insulating property.

The bus bars41,42electrically connect the bus bars200in the energy storage unit20and the positive electrode external terminal13and the negative electrode external terminal14mounted on the first outer covering11to each other. That is, the bus bar41is a conductive member which electrically connects the bus bars200disposed on one end in the energy storage unit20and the positive electrode external terminal13to each other, and the bus bar42is a conductive member which electrically connects the bus bars200disposed on the other end in the energy storage unit20and the negative electrode external terminal14to each other.

The bus bars41,42are made of copper, for example, as conductive members. However, a material for forming the bus bars41,42is not particularly limited. The bus bars41,42may be made of the same material, or may be made of different materials.

The thermistors50are temperature sensors mounted on the holder30with respect to the energy storage devices100. The thermistors50are fixed to the energy storage devices100, and measure temperatures of the energy storage devices100. In this embodiment, two thermistors50are disposed with respect to two energy storage devices100.

Next, the configuration of the energy storage unit20is described in detail.

FIG. 3is an exploded perspective view showing constitutional elements of the energy storage unit20.

As shown inFIG. 3, the energy storage unit20includes: the plurality of energy storage devices100; the plurality of bus bars200; a plurality of spacers300(a plurality of spacers310and a pair of spacers320); a pair of sandwiching members400; a plurality of binding members500; a bus bar frame600; and a heat insulating plate700.

The energy storage device100is a secondary battery (battery) which can charge or discharge electricity. To be more specific, the energy storage device100is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. The energy storage device100has a flat rectangular shape, and is disposed adjacently to the spacer310. That is, the plurality of energy storage devices100and the plurality of respective spacers310are arranged in a row in the X axis direction such that the energy storage device100and the spacer310are alternately arranged. In this embodiment, twelve energy storage devices100and eleven spacers310are arranged such that the energy storage device100and the spacer310are alternately arranged. The energy storage device100is not limited to a nonaqueous electrolyte secondary battery, and may be a secondary battery other than a nonaqueous electrolyte secondary battery, or may be a capacitor.

The energy storage device100includes a container110, a positive electrode terminal120and a negative electrode terminal130. An electrode assembly (power generating element), current collectors (a positive electrode current collector and a negative electrode current collector) and the like are disposed in the container110, and a liquid such as an electrolyte solution (non-aqueous electrolyte) is sealed in the container110. However, the detailed description of such a configuration is omitted.

The container110is formed of a bottomed container body made of metal and having a rectangular cylindrical shape; and a metal-made lid portion which closes an opening of the container body. The container110is configured such that the inside of the container110can be hermetically sealed by joining the lid portion and the container body to each other by welding or the like after the electrode assembly and the like are housed in the container110. The container110is a rectangular parallelepiped container having a lid portion disposed on a plus side in the Z axis direction, long side surfaces disposed on side surfaces of the container on both sides in the X axis direction, short side surfaces disposed on side surfaces of the container on both sides in the Y axis direction, and a bottom surface disposed on a minus side in the Z axis direction. Although a material for forming the container110is not particularly limited, it is preferable that the container110be made of weldable metal such as stainless steel, aluminum or an aluminum alloy.

The positive electrode terminal120is an electrode terminal electrically connected to a positive electrode of an electrode assembly through a positive electrode current collector. The negative electrode terminal130is an electrode terminal electrically connected to a negative electrode of an electrode assembly through a negative electrode current collector. Both the positive electrode terminal120and the negative electrode terminal130are mounted on the lid portion of the container110. The positive electrode terminal120and the negative electrode terminal130are metal-made electrode terminals through which electricity stored in the electrode assembly is discharged to a space outside the energy storage device100, and through which electricity is introduced into a space inside the energy storage device100for storing the electricity in the electrode assembly. In this embodiment, the energy storage devices100are disposed in a state where the positive electrode terminals120and the negative electrode terminals130are directed upward.

The bus bars200are bus bars which are electrically connected to the plurality of respective energy storage devices100housed in the energy storage unit20. That is, the bus bars200are conductive members electrically connected to the respective electrode terminals which the plurality of energy storage devices100include. The bus bars200electrically connect either one of positive and negative electrode terminals of one energy storage device100to the corresponding electrode terminal of another energy storage device100disposed adjacently to one energy storage device. The bus bars200are disposed on surfaces of the respective electrode terminals which the plurality of energy storage devices100include, and are connected (joined) to the electrode terminals.

In this embodiment, five bus bars200are disposed. Twelve energy storage devices100are configured such that four sets of energy storage devices100each of which is formed by connecting three energy storage devices100in parallel to each other are connected in series by five bus bars200. The bus bars200disposed at end portions of the energy storage unit20are connected to the above-mentioned bus bars41,42respectively. With such a configuration, the energy storage devices100are electrically connected to the positive electrode external terminal13and the negative electrode external terminal14.

The bus bars200are made of aluminum, for example, as conductive members. However, a material for forming the bus bar200is not particularly limited. All bus bars200may be made of the same material, or some of the bus bars200may be made of different materials.

The spacers300are formed of the plurality of spacers310and the pair of spacers320, and are made of an insulating resin such as PC, PP, PE, PPS, PBT or an ABS resin. The spacers310and320may be made of any material as long as the material has an insulating property and, further, all of spacers310and320may be made of the same material, or some of the spacers310and320may be made of different materials respectively.

The spacer310is a plate-like member which is disposed on a side of the energy storage device100(on the plus side or the minus side in the X axis direction) so as to provide insulation between the energy storage device100and other members. The spacer310is arranged between two energy storage devices100adjacent to each other so as to provide insulation between two energy storage devices100. In this embodiment, twelve energy storage devices100and eleven spacers310are arranged in a row such that the spacer310is disposed between two energy storage devices100adjacent to each other.

The spacer310is formed to cover an approximately half of a front surface side or a back surface side of the energy storage device100(an approximately half of the front surface side or the back surface side when the energy storage device100is divided in two in the X axis direction). That is, a recessed portion is formed on both the front surface side and the back surface side (both surfaces in the X axis direction) respectively, and an approximately half of the energy storage device100is inserted into each recessed portion. With such a configuration, the spacers310disposed on sides of the energy storage device100cover the most part of the energy storage device100. Accordingly, an insulating property between the energy storage devices100and other conductive members can be enhanced by the spacers310.

The spacer320is a plate-like member which is disposed between the sandwiching member400described later and the outer covering10, and provides insulation between the sandwiching member400and the outer covering10. The spacer320also has a function as a buffer member which protects the energy storage unit20when an impact is applied to the outer covering10from the outside. The pair of spacers320is disposed between the pair of sandwiching members400and the outer covering10respectively such that the pair of spacers320sandwiches the pair of sandwiching members400from both sides. The pair of spacers320insulates the energy storage devices100and the like disposed in the energy storage unit20and also protects the energy storage devices100and the like from an impact from the outside.

The sandwiching members400and the binding members500are members which press the energy storage devices100from the outside in the stacking direction of the electrode assembly of the energy storage device100. The sandwiching members400and the binding members500sandwich the plurality of energy storage devices100from both sides in the stacking direction thus pressing each energy storage device100included in the plurality of respective energy storage devices100from both sides. The stacking direction of the electrode assembly of the energy storage devices100means the direction that positive electrodes, negative electrodes and separators of the electrode assembly are stacked, and is equal to the direction (X axis direction) that the plurality of energy storage devices100are arranged in a row. The plurality of energy storage devices100are arranged in a row in the stacking direction.

The sandwiching members400are flat plate-like members (end plates) disposed on both sides of a unit formed of the plurality of energy storage devices100in the X axis direction. The sandwiching members400hold the plurality of energy storage devices100and the plurality of spacers310by sandwiching the unit formed of the plurality of energy storage devices100and the plurality of spacers310from both sides in the arrangement direction (X axis direction) of the plurality of energy storage devices100and the plurality of spacers310. From a viewpoint of strength, the sandwiching members400are respectively formed of a member made of metal (conductive) such as stainless steel or aluminum. However, the material for forming the sandwiching members400is not limited to such metal materials, and the sandwiching members400may be formed of an insulating member having high strength, for example.

The binding member500is an elongated flat-plate-like member (binding bar) which has both ends thereof mounted on the sandwiching members400, and binds the plurality of energy storage devices100to each other. The binding member500is disposed so as to straddle over the plurality of energy storage devices100and the plurality of spacers310thus applying a binding force to the plurality of energy storage devices100and plurality of spacers310in the arrangement direction (X axis direction) thereof.

In this embodiment, two binding members500are disposed on both sides (both sides in the Y axis direction) of the unit formed of the plurality of energy storage devices100, and two binding members500bind the plurality of energy storage devices100to each other by sandwiching the plurality of energy storage devices100from both sides. In the same manner as the sandwiching members400, the binding members500are preferably made of metal such as stainless steel or aluminum. However, the binding members500may be made of a material other than metal.

The bus bar frame600is a member which can provide insulation between the bus bars200and other members, and can regulate the positions of the bus bars200. Particularly, the bus bar frame600performs the positioning of the bus bars200with respect to the plurality of energy storage devices100disposed in the energy storage unit20.

The bus bar frame600is disposed on an upper side of the plurality of energy storage devices100(a plus side in the Z axis direction), and is positioned with respect to the plurality of energy storage devices100. The bus bars200are placed on an upper side of the bus bar frame600and are positioned. With such a configuration, the bus bars200are positioned with respect to the plurality of energy storage devices100, and are joined to electrode terminals which the plurality of energy storage devices100respectively include. Although the bus bar frame600is made of an insulating resin material such as PC, PP, PE, PPS, PBT or an ABS resin, for example, the bus bar frame600may be made of any material as long as the material has an insulating property.

The heat insulating plate700is a plate-like member having a heat insulating property which is disposed in a flow passage of an exhaust discharged from safety valves of the energy storage devices100. To be more specific, the heat insulating plate700is disposed above the bus bar frame600to be positioned above the safety valves of the energy storage devices100. When an abnormal state occurs such as a case where a gas is discharged from the safety valve of the energy storage device100, the heat insulating plate700protects electric equipment such as a printed circuit board disposed above the energy storage unit20from heat of the gas. In this embodiment, the heat insulating plate700is made of a metal material having low thermal conductivity such as stainless steel. However, a material for forming the heat insulating plate700is not limited to such a metal material, and the heat insulating material700may be made of a resin such as PPS or PBT which is reinforced by glass fibers or ceramics, for example, as long as the material has a high heat resistance and a low thermal conductivity.

In the energy storage apparatus1having the above-mentioned configuration, the configuration of the first outer covering11is described in detail.

FIG. 4is an exploded perspective view showing a schematic configuration of the first outer covering11. InFIG. 1andFIG. 2, the first outer covering11is schematically shown. However, inFIG. 4, the first outer covering11is shown in more detail.

As shown inFIG. 4, the first outer covering11includes a lid body80and a cover body90in a separable manner. The lid body80closes an opening of the second outer covering12, and the cover body90covers a portion of the lid body80.

The lid body80is formed as an integral body using the above-mentioned insulating resin material, and includes a top plate portion81and an edge portion82.

The top plate portion81is a portion facing the opening of the second outer covering12. The top plate portion81includes an exposed portion83which is not covered by the cover body90, and a covered portion84which is covered by the cover body90.

The exposed portion83is formed into an approximately flat shape, and the positive electrode external terminal13and the negative electrode external terminal14are disposed on the exposed portion83. A wall portion85is formed on the covered portion84in a standing manner at a boundary between the covered portion84and the exposed portion83. Electric equipment such as a printed circuit board99and relays (not shown in the drawing), and wirings (not shown in the drawing) for connecting such electric equipment and the energy storage devices100in the energy storage unit20to each other are disposed in a region inside the wall portion85. A plurality of openings84afor guiding the wirings toward the second outer covering12side are formed in a bottom portion of the covered portion84.

On the printed circuit board99, a control circuit is mounted. The control circuit acquires, monitors and controls various kinds of information such as a charging state and a discharging state of the energy storage devices100, a voltage value, a current value, and a temperature of the energy storage device100. Further, the control circuit controls ON and OFF of the relays and performs communication with other equipment. InFIG. 4, only a connector99awhich is a part of the control circuit is shown.

Various kinds of electric equipment disposed on an inner side of the covered portion84are covered by the cover body90and hence, such electric equipment are protected from an impact or the like and, at the same time, it is possible to prevent the electric equipment from coming into contact with external metal members and the like.

In the covered portion84, assume a region where the printed circuit board99is disposed as a circuit board installation region840. The circuit board installation region840is disposed on one end portion of the covered portion84on a plus side in the X axis direction. The printed circuit board99is disposed in the circuit board installation region840in a horizontal state (in parallel to the XY plane), and is housed in the first outer covering11by being covered by the cover body90. That is, the first outer covering11is a housing part which houses the printed circuit board99therein.

The circuit board installation region840adopts the drain structure. However, the detail of the drain structure is described later.

The edge portion82extends downward from a peripheral edge of the top plate portion81over the whole circumference of the top plate portion81, and overlaps with a peripheral edge of the opening of the second outer covering12from the outside. A portion where the edge portion82and the second outer covering12are made to overlap with each other adopts the well-known watertight structure so that it is possible to prevent the intrusion of water into the second outer covering12from the outside.

FIG. 5is a perspective view showing the schematic configuration of the cover body90as viewed from below.

As shown inFIG. 4andFIG. 5, the cover body90is formed as an integral body using the above-mentioned insulating resin material. The cover body90has a shape which corresponds to an outer shape of the covered portion84as viewed in a top plan view, and includes the top plate portion91and the edge portion92.

The top plate portion91is a portion which faces the covered portion84of the lid body80. A recessed portion93which extends along the Y axis direction is formed on the center of an upper surface of the top plate portion91, and portions of the upper surface of the top plate portion91other than the recessed portion93are formed into an approximately flat shape.

As shown inFIG. 5, on a lower surface of the top plate portion91other than the recessed portion93, a grid portion95which projects downward in a grid array is formed. In a facing region950which faces the circuit board installation region840and an outer region960which is disposed adjacently to the facing region95on the lower surface of the top plate portion91, the condensation countermeasure structure is adopted by the grid portion95which corresponds to such regions. The detailed condensation countermeasure structure is described later. Assume a portion of the lower surface of the top plate portion91which covers the printed circuit board99disposed in the circuit board installation region840from above as an upper wall surface911.

The edge portion92extends downward from a peripheral edge of the top plate portion91over the whole circumference thereof, and overlaps with the wall portion85of the lid body80from the outside. A portion where the edge portion92and the wall portion85of the lid body80are made to overlap with each other adopts the well-known watertight structure so that it is possible to prevent the intrusion of water into the covered portion84from the outside.

Next, the drain structure provided to the circuit board installation region840of the lid body80is described.

FIG. 6is a top plan view showing a schematic configuration of the circuit board installation region840.FIG. 7is a cross-sectional view of the first outer covering11taken along a YZ plane which includes a line VII-VII inFIG. 6.FIG. 8is a cross-sectional view of the first outer covering11taken along a ZX plane which includes a line VIII-VIII inFIG. 6. InFIG. 6, an outer shape of the printed circuit board99is indicated by a double dashed chain line.

As shown inFIG. 6toFIG. 8, the circuit board installation region840is a region covered by the printed circuit board99, and is a wall surface disposed below the printed circuit board99. The circuit board installation region840has, as viewed in a top plan view, substantially the same rectangular shape as the printed circuit board99. On four corners of the circuit board installation region840, a circuit board holding portion841for holding the printed circuit board99is formed respectively. Each circuit board holding portion841is formed of a cylindrical projection, and a threaded hole is formed in the circuit board holding portion841.

Out of four circuit board holding portions841, in the vicinity of two circuit board holding portions841disposed on a plus side in the Y axis direction, two positioning portions842for positioning the printed circuit board99are disposed. The positioning portion842is formed of a columnar-shaped body843which projects from the circuit board installation region840; and a columnar-shaped positioning projection844which projects from an upper surface of the body843. An upper surface of the body843of the positioning portion842and an upper surface of the circuit board holding portion841are made coplanar with each other so that the printed circuit board99mounted on the upper surfaces of the body843and the upper surface of the circuit board holding portion841can be held flatly. The upper surface of the body843of the positioning portion842and the upper surface of the circuit board holding portion841are positioned above the wall surface which forms the circuit board installation region840and hence, the printed circuit board99and the circuit board installation region840are disposed in a spaced-apart manner from each other. As shown inFIG. 4, in the printed circuit board99, a through hole991which communicates with the threaded hole formed in the circuit board holding portion841is formed at four corners of the printed circuit board99. By making screws threadedly engage with the threaded holes of the circuit board holding portion841through the through holes991, the printed circuit board99is fixed in the circuit board installation region840. Through holes992into which positioning projections844are inserted are formed in the printed circuit board99. In mounting the printed circuit board99on the circuit board installation region840, the printed circuit board99can be positioned on the XY plane by inserting the positioning projections844into the through holes992.

As shown inFIG. 6, a screw mounting recessed portion845in which a fixing screw (not shown in the drawing) for fixing the heat insulating plate700is disposed is formed on the circuit board installation region840. A through hole846is formed in a bottom surface of the screw mounting recessed portion845, and a fixing screw is made to pass through the through hole846and is threadedly engaged with the threaded hole formed in the heat insulating plate700.

As shown inFIG. 6toFIG. 8, in the circuit board installation region840, a drain passage850for discharging water to the outside of the region is formed. That is, the drain passage850is formed directly below the printed circuit board99in the vertical direction. The drain passage850includes a groove portion851and guide portions852which guide water to the groove portion851.

The groove portion851is a drain groove for discharging water, and extends along the Y axis direction at the center portion of the circuit board installation region840in the X axis direction. A drain port853is formed in both end portions and a center portion of the groove portion851in an extending direction of the groove portion851. The drain ports853are through holes which are formed in a penetrating manner in the vertical direction (Z axis direction), and discharge water which reaches the drain ports853to the outside of the circuit board installation region840.

As shown inFIG. 6, the bus bar41(indicated by a broken line inFIG. 6) disposed below the first outer covering11is disposed at a position horizontally away from an area vertically below the drain port853. With such a configuration, water discharged from the drain port853is suppressed from falling onto the bus bar41. It is preferable that the conductive members other than the bus bar41be also disposed at positions horizontally away from the area vertically below the drain port853. Since it is sufficient that water from the drain port853is prevented from falling onto the conductive member, it is sufficient that the conductive members are not disposed directly below the drain ports853. When the conductive member is disposed vertically below the drain port853, a member which interrupts water may be interposed between the drain port853and the conductive member.

As shown inFIG. 7, the bottom surface856of the groove portion851forms a first inclined surface which is gradually lowered as the bottom surface856extends toward the drain ports853. The bottom surface856disposed between the drain port853on one end of the groove portion851and the drain port853at the center of the groove portion851and the bottom surface856disposed between the drain port853on the other end of the groove portion851and the drain port853at the center of the groove portion851have substantially the same shape. Accordingly, the description is made only with respect to the shape of one bottom surface856.

One bottom surface856is inclined in a mountain-like shape with a center portion thereof in the extending direction formed as a boundary. Accordingly, it is possible to guide water accumulated in the groove portion851to both of the drain port853on one end portion side and the drain port853at the center portion.

The bottom surface856of the groove portion851may be formed into an inclined surface which is continuously inclined at the same angle as a whole. The bottom surface of the groove portion851may be formed into a curved surface. When a drainability is considered not so significant, the bottom surface856of the groove portion851may be formed of a horizontal surface.

As shown inFIG. 6toFIG. 8, the pair of guide portions852is disposed to be opposite to each other with the groove portion851sandwiched therebetween in the X axis direction. Each of the pair of guide portions852has substantially the same shape and hence, in this embodiment, the description is made by exemplifying one guide portion852, and with respect to the other guide portion852, only portions which make the other guide portion852differ from one guide portion852are described later.

One guide portion852includes an inclined surface857(second inclined surface) which is lowered as the inclined surface857extends toward the groove portion851, that is, toward the bottom surface856(first inclined surface). Although the inclined surface857is a flat surface inclined with respect to the X axis direction, the inclined surface857may be a curved surface. A plurality of draining ribs858are arranged in a row at intervals on the inclined surface857in the Y axis direction. The draining rib858is an elongated projection which extends along an inclination direction of the inclined surface857continuously from one end portion to the other end portion of the inclined surface857in the X axis direction. An upper surface of the draining rib858is parallel to the XY plane. A projection amount of the draining rib858from the inclined surface857is gradually increased as the draining rib858extends toward the groove portion851.

A screw mounting recessed portion845is formed on the other guide portion852. A peripheral edge of the screw mounting recessed portion845is raised more upward than the inclined surface857. With such a configuration, water which flows on the inclined surface857minimally enters the screw mounting recessed portion845.

A wall surface which forms the circuit board installation region840is formed of a hydrophobic surface. In forming the lid body80using the above-mentioned insulating resin material, by applying well-known hydrophobic treatment to the wall surface which forms the circuit board installation region840, the wall surface is a hydrophobic surface. Surfaces of respective parts disposed on the circuit board installation region840may be formed into a hydrophobic surface respectively. Further, the whole surface of the covered portion84of the lid body80may be formed into a hydrophobic surface.

Next, the operation of the drain structure provided to the circuit board installation region840of the lid body80is described.

During the use of the energy storage apparatus1, there may be a case where dew condensation occurs in the outer covering10because of difference in temperature between the inside and the outside of the outer covering10. For example, assume that dew condensation occurs in the circuit board installation region840of the lid body80. Condensed dew generated on the inclined surface857is gradually guided to the groove portion851due to the inclination of the inclined surface857. At this stage of operation, the wall surface on which the circuit board installation region840is formed is a hydrophobic surface and hence, the condensed dew is smoothly guided to the groove portion851.

There may be also a case where condensed dew generated in the vicinity of the draining rib858is brought into contact with the draining rib858so that the condensed dew is merged with other condensed dew to be liquid droplets. When condensed dews are merged to form liquid droplets, the own weight of merged condensed dews is increased. The draining rib858can also be a passage for guiding the liquid droplets to the groove portion851. Accordingly, condensed dews can be more smoothly guided to the groove portion851.

The condensed dew (water) guided to the groove portion851is guided to the respective drain ports853due to the inclination of the bottom surface856of the groove portion851, and is discharged to the outside of the lid body80from the drain ports853.

Next, the condensation countermeasure structure provided to the grid portion95of the cover body90is described.

As shown inFIG. 5,FIG. 7andFIG. 8, the grid portion95includes a plurality of plate-like first wall bodies951which extend along the Y axis direction, and a plurality of plate-like second wall bodies952which extend in the X axis direction. The plurality of first wall bodies951and the plurality of second wall bodies952intersect with each other respectively and hence, the grid portion95has a grid array as viewed from the Z axis direction. In the grid portion95having such a configuration, the condensation countermeasure structure is applied to portions of the grid portion95which are disposed in the facing region950and the outer region960of the top plate portion91respectively.

The facing region950is a region which faces the circuit board installation region840as viewed in a plan view, that is, a region which faces the printed circuit board99. The outer region960is an annular region which surrounds the facing region950as viewed in a plan view and is disposed adjacently to the facing region950. A region obtained by combining the outer region960and the facing region950is referred to as a condensation countermeasure region970.

In regions other than the condensation countermeasure region970in the grid portion95, the first wall bodies951and the second wall bodies952are formed substantially at the same height as a whole. However, in such regions other than the condensation countermeasure region970, there are portions where the height of the wall bodies is not fixed partially. The mounting positions and the heights of the first wall bodies951and the second wall bodies952are decided by a height of an article (for example, electric equipment or the like) to be housed in the first outer covering11.

As shown inFIG. 7, the plurality of first wall bodies951in the condensation countermeasure region970are projecting portions each of which projects toward the printed circuit board99side (a minus side in the Z axis direction) from the upper wall surface911, and are formed continuously in an elongated manner in the Y axis direction along the upper wall surface911. The plurality of first wall bodies951in the condensation countermeasure region970are arranged in a row at predetermined intervals in the X axis direction. The plurality of first wall bodies951in the condensation countermeasure region970form first inclined portions each of which becomes highest at a center portion thereof in the Y axis direction so that the first inclined portion is away from the printed circuit board99, and is gradually lowered as the first inclined portion extends toward an edge of the condensation countermeasure region970so that the first inclined portion approaches the printed circuit board99. In the first wall body951which forms the first inclined portion, a projection amount from the upper wall surface911becomes minimum at the center portion thereof in the Y axis direction, and is gradually increased as the first wall portion951extends toward the edge of the condensation countermeasure region970. A lower end surface of the first wall body951which forms the first inclined portion is a flat surface which is inclined such that the lower end surface is gradually lowered as the first wall body951extends from the center portion thereof to the edge of the facing region950. As described above, the first wall body951which forms the first inclined portion is formed continuously from the facing region950to the outer regions960, and an outer region960side of the first wall body951is lower than the facing region950side of the first wall body951.

In this embodiment, the case is exemplified where the lower end surface of the first wall body951which forms the first inclined portion is a flat surface. However, the lower end surface may be a curved surface.

As shown inFIG. 7andFIG. 8, the plurality of second wall bodies952in the condensation countermeasure region970are projecting portions each of which projects toward the printed circuit board99side (a minus side in the Z axis direction) from the upper wall surface911, and extend in the X axis direction along the upper wall surface911. The plurality of second wall bodies952in the condensation countermeasure region970are disposed between the plurality of first wall bodies951, and are arranged in a row at predetermined intervals in the Y axis direction. The plurality of second wall bodies952in the condensation countermeasure region970form the second inclined portions each of which is gradually lowered as the second inclined portion extends toward the first inclined portions. A lower end surface of the second wall body952which forms the second inclined portion is a curved surface which becomes highest at the center portion thereof in the X axis direction so that the second wall body952is away from the printed circuit board99at the center portion thereof between the first wall bodies951adjacent to each other, and is gradually lowered as the lower end surface extends toward the first wall bodies951so that the second wall body952approaches the printed circuit board99. The lower end surface of the second wall body952which forms the second inclined portion is a concave curved surface which is recessed upward. With respect to the second wall body952which forms the second inclined portion, a projection amount from the upper wall surface911becomes minimum at a center portion of the second wall body952between the first wall bodies951adjacent to each other, and is gradually increased as the second wall body952extends toward the first wall body951.

The case is exemplified where the lower end surface of the second wall body952is a concave surface, the lower end surface may be an inclined flat surface. In this embodiment, however, a lower end surface of a second wall body952adisposed on the most plus side in the X axis direction is a flat inclined surface which is gradually lowered as the lower end surface extends from one first wall body951which is disposed on a minus side in the X axis direction out of the first wall bodies951adjacent to each other to the other first wall body951.

The plurality of second wall bodies952are formed to have a height (projection amount) which corresponds to a height (projection amount) of the corresponding first wall bodies951respectively. That is, a lower end surface of the second wall body952which is disposed at a higher portion of the first wall bodies951is disposed at a higher position, and a lower end surface of the second wall body952which is disposed at a lower portion of the first wall bodies951is disposed at a lower position. To describe the above-mentioned configuration in more detail with reference toFIG. 7, a lower end surface of the second wall body952awhich corresponds to a highest portion of the first wall body951is higher than the lower end surfaces of other second wall bodies952. On the other hand, a lower end surface of a second wall body952bwhich corresponds to a lowest portion of the first wall body951is lower than the lower end surfaces of other second wall bodies952.

The upper wall surface911which forms the condensation countermeasure region970is a hydrophilic surface. In forming the cover body90using the above-mentioned insulating resin material, by applying well-known hydrophilic treatment to the upper wall surface911which forms the condensation countermeasure region970, the upper wall surface911is a hydrophilic surface. Surfaces of respective parts disposed on the upper wall surface911which form the condensation countermeasure regions970may be formed into a hydrophilic surface respectively. The whole lower surface of the cover body90including the grid portion95may be formed into a hydrophilic surface.

Next, the operation of the condensation countermeasure structure provided to the condensation countermeasure region970of the cover body90is described.

During the use of the energy storage apparatus1, there may be a case where dew condensation occurs in the outer covering10because of difference in temperature between the inside and the outside of the outer covering10. For example, assume that dew condensation occurs in the condensation countermeasure region970of the cover body90. Condensed dew generated on the upper wall surface911reaches the second wall bodies952and the first wall bodies951. Further, condensed dew generated on the second wall bodies952which form the second inclined portions and condensed dew which reaches the second wall bodies952from the upper wall surface911are guided to the first wall bodies951due to the inclination of the lower end surfaces of the second wall bodies952. Condensed dew generated on the first wall bodies951and condensed dew which reaches the first wall bodies951from the second wall bodies952or the upper wall surface911are gradually guided to the outer region960due to the inclination of the lower end surfaces of the first wall bodies951which form the first inclined portions and fall. In this embodiment, the outer region960horizontally projects from the printed circuit board99over the whole circumference and hence, it is possible to suppress the fallen condensed dew from being brought into contact with the printed circuit board99. The fallen condensed dew is discharged to the outside of the lid body80from the drain ports853by the drain structure of the lid body80.

As has been described above, in the energy storage apparatus1according to the embodiment of the present invention, in the circuit board installation region840on the wall surface below the printed circuit board99, the drain passage850for discharging condensed dew to the outside of the circuit board installation region840is formed and hence, it is possible to suppress the condensed dew from accumulating in the circuit board installation region840. Accordingly, it is possible to suppress short-circuiting of the printed circuit board99caused by the condensed dew.

The bottom surface856of the drain passage850is the first inclined surface which is gradually lowered as the first inclined surface extends toward the drain port853and hence, drain water can be guided to the drain ports853with certainty.

The bus bar41is disposed at the position away from the area vertically below the drain port853in the horizontal direction and hence, drain water can be prevented from falling on the bus bar41. Accordingly, it is possible to prevent short-circuiting of the energy storage apparatus1per se caused by drain water.

The inclined surface857(second inclined surface) which is lowered as the inclined surface857extends toward the bottom surface856of the drain passage850is formed in the circuit board installation region840which faces the printed circuit board99. Accordingly, the dew condensation generated in the circuit board installation region840can be guided to the groove portion851by the inclined surface857.

The draining ribs858each of which is elongated along the inclination direction are formed on the inclined surface857and hence, the condensed dew can be easily collected as liquid droplets and, at the same time, the liquid droplets can be guided to the groove portion851of the drain passage850by the draining ribs858.

In this embodiment, the description is made by exemplifying the case where the draining ribs858which project from the inclined surface857are formed on the inclined surface857. However, a groove portion which is elongated along the inclination direction may be formed on the inclined surface857in place of forming the draining ribs858. Also in this case, it is possible to acquire advantageous effect substantially equal to the advantageous effects as which the draining ribs858can acquire.

The printed circuit board99is disposed in a spaced-apart manner from the wall surface which forms the circuit board installation region840and hence, it is possible to prevent the printed circuit board99from being brought into contact with the condensed dew generated on the circuit board installation region840.

The wall surface which forms the circuit board installation region840is a hydrophobic surface and hence, it is possible to accelerate the flow of condensed dew generated on the wall surface.

The first wall bodies951which form the first inclined portions are formed on the region of the upper wall surface911of the outer covering11which covers the printed circuit board99and hence, it is possible to guide the condensed dew to a desired position using the first wall bodies951as a guide. Accordingly, it is possible to suppress falling of condensed dew onto the printed circuit board99and hence, short-circuiting of the printed circuit board99can be suppressed.

The first wall bodies951which form the first inclined portions are continuously formed to the outer region960and hence, it is possible to guide the condensed dew to the outside of the printed circuit board99. Accordingly, it is possible to suppress falling of condensed dew onto the printed circuit board99more effectively.

The first wall bodies951which form the first inclined portions are formed of the elongated projecting portions. Accordingly, compared to a case where the upper wall surface is simply inclined, condensed dew is minimally fallen and hence, condensed dew can be easily merged as liquid droplets.

The plurality of first wall bodies951which form the first inclined portions are disposed at intervals. Accordingly, the condensed dew can be guided in a wide range.

There are provided the second inclined portions (second wall bodies952) which are gradually lowered as the second inclined portions extend toward the first wall bodies951which form the first inclined portions. Accordingly, the condensed dew can be guided to the first wall bodies951by the second wall bodies952whereby the condensed dew can be easily guided to the first wall bodies951.

The upper wall surface911is a hydrophilic surface and hence, it is possible to suppress falling of the condensed dew generated on the upper wall surface911.

Next, a modification 1 of the above-mentioned embodiment is described. In the above-mentioned embodiment, the case is described where, in the grid portion95, the first wall bodies951in the condensation countermeasure region970form the first inclined portions. However, the first inclined portion may have any shape as long as the first inclined portion is gradually lowered as the first inclined portion extends toward the edge of the condensation countermeasure region970.

Hereinafter, a case where the first inclined portion is a flat surface is described with reference toFIG. 9andFIG. 10. In the description made hereinafter, parts identical with the parts of the above-mentioned embodiment are given the same symbols and their repeated description is omitted.

FIG. 9is a cross-sectional view of a first outer covering11A according to the modification 1, and is a view which corresponds toFIG. 7.FIG. 10is a cross-sectional view of the first outer covering11A according to the modification 1, and is a view which corresponds toFIG. 8.

As shown inFIG. 9andFIG. 10, an upper wall surface911awhich forms a condensation countermeasure region970A of a cover body90A of the first outer covering11A is an inclined surface as a whole. That is, the upper wall surface911aforms a first inclined portion which is gradually lowered as the upper wall surface911aextends toward an edge of the condensation countermeasure region970A. To be more specific, the upper wall surface911ahas an inclination gradually lowered toward a minus side in the Y axis direction as viewed in a direction shown inFIG. 7, and has an inclination gradually lowered toward a plus side in the X axis direction as viewed in a direction shown inFIG. 8.

As described above, the upper wall surface911awhich is an inclined surface forms the first inclined portion and hence, it is possible to guide condensed dew to a desired position with the simple configuration.

The first inclined portion may not be formed of the inclined surface which forms the whole upper wall surface911abut may be formed of an inclined surface formed by inclining at least a portion of the upper wall surface. The first inclined portion may be a curved surface.

Although the energy storage apparatuses according to the embodiment of the present invention and the modifications of the embodiment have been described heretofore, the present invention is not limited to the above-mentioned embodiment and the modification of the embodiment. The embodiment and the modification of the embodiment disclosed in this specification are only for an exemplifying purpose in all aspects and are not limited. The scope of the present invention is not designated by the above-mentioned description but is designated by Claims, and it is intended that all modifications which fall within the meaning and the scope equivalent to Claims are also included in the scope of the present invention. The configurations which are made by arbitrarily combining the respective constitutional elements which the above-mentioned embodiment and the modification of the embodiment include are also included in the scope of the present invention.

For example, in the above-mentioned embodiment and the modification of the embodiment, the case has been exemplified where the drain structure is applied to the circuit board installation region840of the lid body80. However, the drain structure may be applied to a region of the lid body80other than the circuit board installation region840or to the whole lid body80. Particularly, from a viewpoint of suppressing short-circuiting, it is preferable to apply the drain structure to a region where electric equipment other than the printed circuit board99is mounted.

In the above-mentioned embodiment and the modification of the embodiment, the case has been exemplified where the condensation countermeasure structure is applied to the condensation countermeasure region970of the cover body90. However, the condensation countermeasure structure may be applied to a region of the cover body90other than the condensation countermeasure region970or to the whole grid portion95of the cover body90. Particularly, from a viewpoint of suppressing short-circuiting, it is preferable to apply the condensation countermeasure structure to a region which covers electric equipment other than the printed circuit board99.

In the above-mentioned embodiment and the modification of the embodiment, the case has been described where the drain structure and the condensation countermeasure structure are applied to the printed circuit board99which is one of electric equipment. However, at least one of the drain structure and the condensation countermeasure structure may be also applied to other electric equipment such as a relay incorporated in the outer covering10.

In the above-mentioned embodiment, the first outer covering11is exemplified as the housing part for housing the printed circuit board99therein. However, the housing part is not limited to the first outer covering11as long as the housing part can house the printed circuit board99in the outer covering11. For example, in a case where a dedicated casing for housing the printed circuit board99therein is disposed in the outer covering11, the casing may be used as the housing part.

The present invention is applicable to an energy storage apparatus provided with energy storage devices and an outer covering.