ENERGY STORAGE APPARATUS

An energy storage apparatus includes: an energy storage device; and a first spacer and a second spacer that sandwich the energy storage device. The first spacer includes: a first body portion facing the energy storage device; a first wall portion protruding from the first body portion toward the second spacer along the energy storage device; and a first protruding portion protruding from the first wall portion. The second spacer includes: a second body portion acing the energy storage device; a second wall portion protruding from the second body portion toward the first wall portion along the energy storage device; and a second protruding portion protruding from the second wall portion. The first protruding portion includes a spaced-apart portion where a distance between the first protruding portion and the second protruding portion is larger than a distance between the first wall portion and the second wall portion.

TECHNICAL FIELD

The present invention relates to an energy storage apparatus which includes an energy storage device and two spacers that sandwich the energy storage device.

BACKGROUND ART

Conventionally, there has been popularly known an energy storage apparatus which includes an energy storage device and two spacers that sandwich the energy storage device. In Patent Document 1, there is disclosed an energy storage apparatus where energy storage devices and spacers are alternately stacked. The spacer has facing surfaces that face the energy storage devices disposed adjacently to the spacer, side surfaces, and leg portions that protrude from the side surfaces and support the spacer.

PRIOR ART DOCUMENT

Patent Document

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In the above-mentioned conventional energy storage apparatus, there is a concern that the energy storage device and an external conductive member may be electrically conductive with each other.

It is an object of the present invention to provide an energy storage apparatus capable of preventing an energy storage device and an external conductive member from becoming conductive with each other.

Means for Solving the Problems

An energy storage apparatus according to one aspect of the present invention is an energy storage apparatus which includes: an energy storage device; and a first spacer and a second spacer that sandwich the energy storage device in a first direction, wherein the first spacer includes: a first body portion facing the energy storage device in the first direction; a first wall portion protruding from the first body portion toward the second spacer along the energy storage device; and a first protruding portion protruding from the first wall portion in a second direction that intersects with the first direction, the second spacer includes: a second body portion facing the energy storage device in the first direction; a second wall portion protruding from the second body portion toward the first wall portion along the energy storage device; and a second protruding portion protruding from the second wall portion in the second direction, wherein the first protruding portion includes a spaced-apart portion where a distance between the first protruding portion and the second protruding portion is larger than a distance between the first wall portion and the second wall portion in the first direction.

The present invention can be realized not only as such an energy storage apparatus but also as a spacer (a first spacer, a second spacer).

Advantages of the Invention

According to the energy storage apparatus of the present invention, it is possible to prevent the energy storage device and the external conductive member from becoming conductive with each other.

MODE FOR CARRYING OUT THE INVENTION

In the above-mentioned conventional energy storage apparatus, there is a concern that the energy storage device and an external conductive member may be electrically conductive with each other. In the energy storage apparatus disclosed in Patent Document 1, each of the spacers that are alternately arranged with the energy storage devices has a leg portion, and the leg portions of the respective spacers are arranged in the arrangement direction of the energy storage devices and the spacers. In view of the above, the inventors of the present application have found out that when a gap formed between the legs of two spacers that sandwich the energy storage device is small, there is a concern that a liquid such as water produced by dew condensation or the like intrudes into the gap from above the gap or the liquid creeps up through the gap from below so that the liquid is accumulated in the gap. When the liquid is accumulated in the gap, there is a concern that the energy storage devices and an external conductive member (such as a metal plate on which the energy storage apparatus is mounted) become conductive with each other through the liquid.

It is an object of the present invention to provide an energy storage apparatus capable of preventing an energy storage device and an external conductive member from becoming conductive with each other.

An energy storage apparatus according to one aspect of the present invention is an energy storage apparatus which includes: an energy storage device; and a first spacer and a second spacer that sandwich the energy storage device in a first direction, wherein the first spacer includes: a first body portion facing the energy storage device in the first direction; a first wall portion protruding from the first body portion toward the second spacer along the energy storage device; and

a first protruding portion protruding from the first wall portion in a second direction that intersects with the first direction, the second spacer includes: a second body portion facing the energy storage device in the first direction; a second wall portion protruding from the second body portion toward the first wall portion along the energy storage device; and a second protruding portion protruding from the second wall portion in the second direction, wherein the first protruding portion includes a spaced-apart portion where a distance between the first protruding portion and the second protruding portion is larger than a distance between the first wall portion and the second wall portion in the first direction.

With such a configuration, in the energy storage apparatus, the first spacer includes the first wall portion protruding toward the second spacer along the energy storage device and the first protruding portion protruding from the first wall portion. The second spacer includes the second wall portion protruding toward the first wall portion along the energy storage device, and the second protruding portion protruding from the second wall portion. The first protruding portion includes the spaced-apart portion where the distance between the first protruding portion and the second protruding portion is larger than the distance between the first wall portion and the second wall portion. In this manner, the first protruding portion and the second protruding portion are formed on the first spacer and the second spacer, and the spaced-apart portion of the first protruding portion is formed such that the distance between the first protruding portion and the second protruding portion is larger than the distance between the first wall portion and the second wall portion. As a result, when a liquid such as water enters between the first protruding portion and the second protruding portion from above, the liquid easily falls at the position of the spaced-apart portion. On the other hand, it is difficult for a liquid such as water from below to creep up at the position of the spaced-apart portion and hence, it is difficult for the liquid to be accumulated between the first protruding portion and the second protruding portion. Accordingly, it is possible to prevent the liquid from being accumulated between the first protruding portion and the second protruding portion and hence, it is possible to prevent the energy storage device and an external conductive member (such as a metal plate on which the energy storage apparatus is mounted) from becoming conductive with each other.

The spaced-apart portion may include a first inclined surface that is inclined in a direction that the first inclined surface is disposed away from the second protruding portion as the first inclined surface is disposed away from the first wall portion.

In such a configuration, the spaced-apart portion of the first protruding portion of the first spacer includes the first inclined surface that is inclined in the direction that the first inclined surface is disposed away from the second protruding portion of the second spacer as the first inclined surface is disposed away from the first wall portion. By forming the first inclined surface on the spaced-apart portion of the first protruding portion in this manner, a liquid such as water is more likely to fall at the position of the spaced-apart portion. On the other hand, it is difficult for a liquid such as water from below to creep up at the position of the spaced-apart portion. As a result, a liquid is less likely to be accumulated between the first protruding portion and the second protruding portion and hence, it is possible to more effectively prevent the energy storage device and an external conductive member from being conductive with each other.

The second protruding portion may include a second inclined surface that is inclined in a direction that the second inclined surface is disposed away from the spaced-apart portion as the second inclined surface is disposed away from the second wall portion.

In such a configuration, the second protruding portion of the second spacer includes the second inclined surface that is inclined in the direction that the second inclined surface is disposed away from the spaced-apart portion of the first protruding portion of the first spacer as the second inclined surface is disposed away from the second wall portion. By forming the second inclined surface on the second protruding portion in this manner, a liquid such as water is more likely to fall at the position of the spaced-apart portion of the first protruding portion. On the other hand, it is more difficult for a liquid such as water from below to creep up at the position of the spaced-apart portion. As a result, a liquid is less likely to be accumulated between the first protruding portion and the second protruding portion and hence, it is possible to more effectively prevent the energy storage device and an external conductive member from being conductive with each other.

The first protruding portion may include a third inclined surface on a surface thereof opposite to the second protruding portion, wherein the third inclined surface is inclined in a direction that the third inclined surface approaches the second protruding portion as the third inclined surface is disposed away from the first wall portion.

In such a configuration, the first protruding portion of the first spacer includes the third inclined surface which is inclined in a direction that the third inclined surface approaches the second protruding portion as the third inclined surface is disposed away from the first wall portion on the surface of first protruding portion of the first spacer opposite to the second protruding portion of the second spacer. In this manner, by forming the third inclined surface on the surface of the first protruding portion on the side opposite to the second protruding portion, also on the side of the first protruding portion opposite to the second protruding portion, a liquid such as water from above is likely to fall. On the other hand, it is difficult for a liquid such as water from below to creep up. As a result, the liquid is less likely to be accumulated even on the side of the first protruding portion opposite to the second protruding portion and hence, it is possible to prevent the energy storage device and the external conductive member from becoming conductive with each other.

The spaced-apart portion may include a recessed portion that is recessed in a direction away from the second protruding portion.

In such a configuration, the spaced-apart portion of the first protruding portion of the first spacer includes the recessed portion recessed in the direction away from the second protruding portion of the second spacer. By forming the recessed portion in the spaced-apart portion of the first protruding portion in this manner, a liquid such as water is more likely to fall at the position of the spaced-apart portion. On the other hand, it is more difficult for a liquid such as water from below to creep up at the position of the spaced-apart portion. As a result, a liquid is less likely to be accumulated between the first protruding portion and the second protruding portion and hence, it is possible to more effectively prevent the energy storage device and an external conductive member from being conductive with each other.

Assuming that a distance between the first protruding portion and the second protruding portion in the first direction at the spaced-apart portion is set as a, a length of the spaced-apart portion in a third direction that intersects with the first direction and the second direction is set as b, a length of the spaced-apart portion in the second direction is set as h, a surface tension when a liquid that is disposed between the first protruding portion and the second protruding portion is brought into contact with air is set as σ, a contact angle between a wall surface of the spaced-apart portion and the liquid is set as θ, density of the liquid is set as ρ, and gravitational acceleration is set as g, the distance a between the first protruding portion and the second protruding portion in the first direction at the spaced-apart portion may satisfy a following formula.

The inventors of the present application have found out that, when the distance between the first protruding portion and the second protruding portion at the spaced-apart portion satisfies the above formula, even when a liquid such as water creeps up between the first protruding portion and the second protruding portion, the liquid does not creep up above the spaced-apart portion. As a result, it is possible to prevent the energy storage device and the external conductive member from becoming conductive with each other.

Hereinafter, energy storage apparatuses according to an exemplary embodiment (and modifications of the present exemplary embodiment) of the present invention are described with reference to drawings. The present exemplary embodiment described hereinafter describes a comprehensive or specific example of an energy storage apparatus. In the following exemplary embodiment, numerical values, shapes, materials, constitutional elements, arrangement positions and connection modes of the constitutional elements, manufacturing steps, the order of the manufacturing steps, and the like are provided as examples, and are not intended to limit the present invention. The respective drawings are schematic views, and the sizes and the like are not necessarily strictly illustrated. In the respective drawings, identical or substantially identical constitutional elements are given the same symbols.

In the following description and drawings, an arrangement direction along which a plurality of energy storage devices, a plurality of spacers and two end members are arranged, a direction along which long-side surfaces of a container of an energy storage device face each other, or a thickness direction of the container is defined as an X-axis direction. A direction along which a pair of electrode terminals (on a positive electrode side and a negative electrode side) of one energy storage device are arranged, a direction along which short-side surfaces of a container of the energy storage device face each other, or a direction along which two side members are arranged is defined as a Y-axis direction. A direction along which a container body and a lid of the energy storage device are arranged or a vertical direction is defined as a Z-axis direction. These X axis direction, Y axis direction, and Z axis direction are directions that intersect with each other (orthogonal to each other in this exemplary embodiment).

In the description made hereinafter, an X-axis plus direction indicates an arrow direction of the X axis, and an X-axis minus direction indicates a direction opposite to the X-axis plus direction. The same goes for the Y axis direction and the Z axis direction. In the following description, there may be a case where the X-axis direction is also referred to as a first direction, the Z-axis direction or the Z-axis minus direction is also referred to as a second direction, and the Y-axis direction is referred to as a third direction. Expressions indicating the relative directions or the relative postures such as “parallel” or “orthogonal” also include cases where such directions or postures are not considered as such directions or such postures in a strict meaning of the terms. A state where two directions are orthogonal to each other means not only a state where these two directions are completely orthogonal to each other but also a state where these two directions are substantially orthogonal to each other, that is, a state where these two directions are orthogonal to each other with slight difference of about a few percent.

Exemplary Embodiment

[1 Overall Description of Energy Storage Apparatus10]

First, the overall description of the energy storage apparatus10according to the present exemplary embodiment will be made.FIG. 1is a perspective view illustrating an external appearance of the energy storage apparatus10according to the present exemplary embodiment.FIG. 2is an exploded perspective view of the energy storage apparatus10according to the present exemplary embodiment illustrating respective constitutional elements when the energy storage apparatus10is disassembled.

The energy storage apparatus10is an apparatus in which electricity is charged from the outside and from which electricity is discharged to the outside. In the present exemplary embodiment, the energy storage apparatus10has an approximately rectangular parallelepiped shape. The energy storage apparatus10is a battery module (assembled battery) used in an electricity storage application, a power source application, or the like. To be more specific, the energy storage apparatus10is used as a battery or the like for driving a mobile body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agriculture machine, a construction machine, or a railway vehicle for an electric railway, or is used as a battery for starting an engine of the mobile body. As the above-mentioned automobile, an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a gasoline automobile are exemplified. As the above-mentioned railway vehicle for an electric railway, an electric train, a monorail, and a linear motor car are exemplified. The energy storage apparatus10can also be used as a stationary battery or the like used as a home-use battery, a generator, or the like.

As illustrated inFIG. 1andFIG. 2, the energy storage apparatus10includes: a plurality of (twenty in the present exemplary embodiment) energy storage devices100; a plurality of (twenty-one in the present exemplary embodiment) spacers200; two (a pair of) end members300; and two (a pair of) side members400. The energy storage apparatus10may include: an exterior body (a module case) that houses these plurality of energy storage devices100; bus bars that electrically connect the energy storage devices100to each other; a bus bar frame (a bus bar plate) that performs positioning of the bus bars; and electrical equipment such as a circuit board or a relay that monitors a charging state or a discharging state of the energy storage devices100. However, the illustration of these constitutional elements is omitted, and the detailed description of these constitutional elements is also omitted.

The energy storage device100is a secondary battery (single battery) that can charge electricity and discharge electricity. More specifically, the energy storage device100is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. The energy storage device100has a flat rectangular parallelepiped shape (prismatic shape), and is disposed adjacently to the spacers200. That is, the plurality of respective energy storage devices100and the plurality of respective spacers200are arranged in the X axis direction in a state where the energy storage devices100and the spacers200are alternately arranged. In the present exemplary embodiment, twenty energy storage devices100each are arranged between spacers200disposed adjacently to each other out of twenty-one spacers200. The detailed configuration of the energy storage device100is described later.

The number of energy storage devices100is not limited to twenty, and may be one or plural other than twenty. The connection mode of the energy storage devices100is not in particular limited. All of energy storage devices100may be connected in series, or any of the energy storage devices100may be connected in parallel. The shape of the energy storage device100is not in particular limited to a rectangular parallelepiped shape. Other than the rectangular parallelepiped shape, the energy storage device100may have any shape such as a polygonal columnar shape, a circular columnar shape, an elliptical columnar shape, or an oblong circular columnar shape. Further, the energy storage device100may be a laminate-type energy storage device. The energy storage device100is not limited to a nonaqueous electrolyte secondary battery. The energy storage device100may be a secondary battery other than the nonaqueous electrolyte secondary battery, or may be a capacitor. The energy storage device100is not necessarily a secondary battery, and may be a primary battery that allows a user to use stored electricity even when the user does not charge the battery. Further, the energy storage device100may be a battery that uses a solid electrolyte.

The spacer200is a rectangular plate-shaped spacer. The spacer200is arranged on a side (the X-axis plus direction or the X-axis minus direction) of the energy storage device100. The spacer200electrically insulates the energy storage device100from other members, and prevents the swelling of the energy storage device100. The spacer200is formed of an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), a polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene/perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyether sulfone (PES), an ABS resin, or a composite material of the above-mentioned materials. The spacer200may be made of a material other than a resin provided that the spacer200has electric insulation property. The spacer200may be made of ceramic, a mica plate formed using a dammer material formed by stacking and joining mica flakes, or the like. It may not always be the case where all of the plurality of spacers200are made of the same material.

The spacer200includes a plurality of (nineteen in the present exemplary embodiment) intermediate spacers201and two (a pair of) end spacers202. The intermediate spacer201is a rectangular and flat spacer. The intermediate spacer201is sandwiched between two energy storage devices100disposed adjacently to each other and provides electrical insulation between two energy storage devices100. The end spacer202is a rectangular and flat spacer. The end spacer202is arranged in a state where the end spacer202is sandwiched between the energy storage device100disposed at the end portion among the plurality of energy storage devices100and the end member300. The end spacer202provides electrical insulation between the energy storage device100and the end member300. The detailed description of the configuration of the spacers200(the intermediate spacer201and the end spacer202) will be made later.

In the present exemplary embodiment, twenty energy storage devices100and nineteen (nineteen pieces of) intermediate spacers201are arranged alternately adjacently to each other in the X-axis direction. However, in a case where the number of energy storage devices100is other than twenty, the number of intermediate spacers201is also appropriately changed corresponding to the number of energy storage devices100. When the number of energy storage devices100is one, the intermediate spacer201is not arranged, and two (a pair of) end spacers202that sandwich the one energy storage device100are arranged.

The end members300and the side members400are restraining members that press (restrain) the energy storage devices100from the outside in the arrangement direction (the X axis direction) of the plurality of energy storage devices100. That is, the end members300and the side members400press (restrain) each energy storage device100included in the plurality of energy storage devices100from both sides of each energy device100in the arrangement direction of the plurality of energy storage devices100by sandwiching the plurality of energy storage devices100from both sides in the arrangement direction. From a viewpoint of ensuring a strength of the end members300and a strength of the side members400, the end members300and the side members400are made of a metal-made material such as aluminum, an aluminum alloy, stainless steel, iron, or a plated steel plate. The material of the end member300and the material of the side member400are not in particular limited. For example, the end member300and the side member400may be made of material having a high strength and electric insulation property. Alternatively, insulation treatment may be applied to the end member300and the side member400.

More specifically, the end members300are end plates (sandwiching members) having a flat block shape, which are disposed on both sides of the plurality of energy storage devices100and the plurality of spacers200from both sides in the X axis direction, and sandwich the plurality of energy storage devices100and the plurality of spacers200in the X axis direction, and hold the plurality of energy storage devices100and the plurality of spacers200. The end member300may be an end plate having a plate shape or the like in place of an end plate having a block shape.

The side members400are each a long and flat side plate (restraining bar) whose both end portions are attached to the end members300. The side members400restrain the plurality of energy storage devices100and the plurality of spacers200. That is, the side members400are disposed in an extending manner in the X axis direction in a state where the side members400stride over the plurality of energy storage devices100and the plurality of spacers200. The side members400impart a restraining force to the plurality of energy storage devices100and the like in the arrangement direction (X axis direction) of the plurality of energy storage devices100and the like. In the present exemplary embodiment, the pair of side members400is disposed on both sides of a set of the plurality of energy storage devices100and the like in the Y axis direction. The pair of respective side members400is mounted on the end portions in the Y axis direction of the pair of end members300at both end portions of the side members400in the X axis direction. With such a configuration, the pair of side members400restrains the plurality of energy storage devices100and the like by sandwiching the plurality of energy storage devices100and the like from both sides in the X axis direction and from both sides in the Y axis direction. The side member400may be formed of a member having a block shape, a rod shape, or the like in place of a side plate having a plate shape.

[2 Description of Configuration of Energy Storage Device100]

Next, the configuration of the energy storage device100is described in detail. All the energy storage devices100included in the energy storage apparatus10have the same configuration. Accordingly, the configuration of one energy storage device100will be described in detail below.FIG. 3is a perspective view illustrating an external appearance of the energy storage device100according to the present exemplary embodiment.

As illustrated inFIG. 3, the energy storage device100includes: a container110; and a pair of electrode terminals120(the electrode terminal120on a positive electrode side and the electrode terminal120on a negative electrode side). In the container110, an electrode assembly, a pair of current collectors (a current collector on a positive electrode side and a current collector on a negative electrode side), an electrolyte solution (nonaqueous electrolyte), and the like are housed. However, these constitutional elements are not illustrated in the drawing. A kind of the electrolyte solution is not in particular limited provided that the performance of the energy storage device100is not impaired, and various kinds of electrolyte solutions can be selected. Spacers may be disposed on sides or the like of the current collector, and an insulating sheet that covers an outer surface of the container110may be disposed.

The container110is a container having a rectangular parallelepiped shape (prismatic shape). The container110includes: a container body111in which an opening is formed; and a lid body112that closes the opening of the container body111. The container body111is a bottomed rectangular cylindrical member that forms a body portion of the container110. The container body111has: two long side surface portions111aon side surfaces of the container body111on both sides in the X axis direction; two short side surface portions111bon side surfaces of the container body111on both sides in the Y axis direction; and a bottom surface portion111con the Z-axis minus direction side.

The long side surface portions111aare rectangular and flat surface portions forming long side surfaces of the container110. In other words, the long side surface portions111aare surface portions disposed adjacent to the bottom surface portion111cand the short side surface portions111b, and each long side surface portion111ahas a larger area than each short side surface portion111b. The short side surface portion111bis a rectangular and flat surface portion forming the short side surface of the container110. In other words, the short side surface portions111bare surface portions disposed adjacent to the bottom surface portion111cand the long side surface portions111a, and each short side surface portion111bhas a smaller area than each long side surface portion111a. The bottom surface portion111cis a rectangular and flat surface portion forming the bottom surface of the container110.

The lid body112is a plate-shaped member having a rectangular shape that forms a lid portion of the container110. The lid body112is disposed on the Z-axis plus direction side of the container body111. On the lid body112, a gas release valve112athat releases a pressure in the container110when such a pressure is increased, a solution filling portion112bthrough which the container110is filled with an electrolyte solution, and the like are also mounted.

With such a configuration, the container110has the structure where the inside of the container110is sealed. Such sealed structure is obtained by housing the electrode assembly and the like in the container body111and, thereafter, by joining the container body111and the lid body112to each other by welding or the like. The material of the container110(the container body111and the lid body112) is not in particular limited. However, for example, it is preferable that the container110be made of metal that is weldable (joinable) such as stainless steel, aluminum, an aluminum alloy, iron, or a plated steel plate.

The electrode terminals120are terminals (a positive electrode terminal and a negative electrode terminal) of the energy storage device100disposed on the lid body112of the container110. The electrode terminals120are electrically connected to a positive electrode plate and a negative electrode plate of the electrode assembly via current collectors. That is, the electrode terminals120are members that are made of metal and are provided for discharging electricity stored in the electrode assembly to a space outside the energy storage device100, and for charging electricity into a space in the energy storage device100to store electricity in the electrode assembly. The electrode terminals120are made of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

The electrode assembly is an energy storage element (power generating element) formed by stacking a positive electrode plate, a negative electrode plate, and a separator to each other. The positive electrode plate that the electrode assembly includes is formed such that a positive active material layer is formed on a positive electrode substrate layer that is an elongated strip-shaped current collecting foil made of metal such as aluminum or an aluminum alloy. The negative electrode plate is formed such that a negative active material layer is formed on a negative electrode substrate layer that is an elongated strip-shaped current collecting foil made of metal such as copper or a copper alloy. As a positive active material used for forming the positive active material layer and a negative active material used for forming the negative active material layer, known materials can be appropriately used provided that these materials can occlude and discharge lithium ions.

The current collectors (the positive electrode current collector and the negative electrode current collector) are members having conductivity and are electrically connected to the electrode terminals120and the electrode assembly. The positive electrode current collector is made of aluminum, an aluminum alloy or the like substantially in the same manner as the positive electrode substrate layer of the positive electrode plate. The negative electrode current collector is made of copper, a copper alloy, or the like substantially in the same manner as the negative electrode substrate layer of the negative electrode plate. Between the lid body112and the electrode terminals120and the current collectors, a gasket is disposed. The gasket is an insulating member provided for ensuring electrical insulation and gas tightness between the lid body112and the electrode terminal120and the current collector.

[3 Description of Configuration of Spacer200]

[3.1 Description of Configuration of Intermediate Spacer201]

Next, the configuration of the spacer200(the intermediate spacer201and the end spacer202) will be described in detail. First, the configuration of the intermediate spacer201will be described. All intermediate spacers201included in the energy storage apparatus10have substantially the same configuration. Accordingly, the configuration of one intermediate spacer201will be described in detail below.FIG. 4is a perspective view illustrating the configuration of the intermediate spacer201according to the present exemplary embodiment. Specifically, (a) inFIG. 4is an enlarged perspective view illustrating the intermediate spacer201illustrated inFIG. 2, and (b) inFIG. 4is a perspective view illustrating the configuration of the intermediate spacer201in (a) inFIG. 4when viewed from below (Z-axis minus direction).

As illustrated inFIG. 4, the intermediate spacer201includes: a spacer body portion210; spacer side wall portions220; a spacer bottom wall portion230; and spacer protruding portions240. The spacer body portion210is a portion having a rectangular shape and a flat plate shape, and forms a body of the intermediate spacer201. The spacer body portion210is disposed parallel to an YZ plane. In the present exemplary embodiment, the spacer body portion210is arranged so as to face the energy storage device100in the X-axis direction (first direction). That is, the spacer body portion210is arranged on an X-axis plus direction side or in an X-axis minus direction side of the energy storage device100in a state where the spacer body portion210covers an entire surface of the long side surface portion111aof the container110of the energy storage device100(seeFIG. 5).

The spacer side wall portions220are portions having a rectangular shape and a flat plate shape, protruding from the spacer body portion210in the X-axis direction, and extending in the Z-axis direction. The spacer side wall portions220are arranged parallel to the XZ plane. Specifically, the spacer side wall portions220protrude toward both sides in the X-axis direction at both ends from both end portions of the spacer body portion210in the Y-axis direction and extend in the Z-axis direction. In the present exemplary embodiment, the spacer side wall portions220are arranged along the short side surface portions111bof the container110of the energy storage device100on both sides of the energy storage device100in the Y-axis direction. Specifically, the spacer side wall portion220is arranged so as to face the energy storage device100in the Y-axis direction in a state where the spacer side wall portion220covers approximately half of the short side surface portion111bof the container110of the energy storage device100on the X-axis plus direction side or the X-axis minus direction side (seeFIG. 5).

The spacer bottom wall portion230is a portion having a rectangular shape and a flat plate-shape, protruding from the spacer body portion210in the X-axis direction, and extending in the Y-axis direction. The spacer bottom wall portion230is arranged parallel to the XY plane. Specifically, the spacer bottom wall portion230protrudes toward both sides in the X axis direction from the end portion of the spacer body portion210on the Z-axis minus direction side and extend portions in the Y axis direction. In the present exemplary embodiment, the spacer bottom wall portion230is arranged along the bottom surface portion111cof the container110of the energy storage device100on the Z-axis minus direction side of the energy storage device100. Specifically, the spacer bottom wall portion230is arranged so as to face the energy storage device100in the Z-axis direction in a state where the spacer bottom wall portion230covers approximately half of the bottom surface portion111cof the container110of the energy storage device100on the X-axis plus direction side or on the X-axis minus direction side (seeFIG. 5).

The spacer protruding portions240are arranged so as to protrude from the spacer side wall portions220in the Z-axis minus direction. Specifically, the spacer protruding portions240protrude in the Z-axis minus direction from both end portions in the Y-axis direction of the spacer bottom wall portion230and extend in the Y-axis direction. The spacer protruding portion240has: an inclined surface241on the surface on the X-axis plus direction side; and an inclined surface242on the surface on the X-axis minus direction side. The inclined surface241is a flat inclined surface that inclines in the X-axis minus direction as the inclined surface241extends portions in the Z-axis minus direction (the remoter the inclined surface241from the spacer side wall portion220and the spacer bottom wall portion230). The inclined surface242is a flat inclined surface that inclines in the X-axis plus direction as the inclined surface242extends portions in the Z-axis minus direction (the remoter the inclined surface242from the spacer side wall portion220and the spacer bottom wall portion230).

The inclined surface241is formed with recessed portions243that are recessed in the X-axis minus direction. The recessed portions243are recessed portions each having a rectangular shape when viewed from the X-axis direction, and two recessed portions243are formed on one inclined surface241. In the same manner, the inclined surface242is also formed with two rectangular recessed portions244(seeFIG. 5) that are recessed in the X-axis plus direction. The recessed portion243formed on the inclined surface241and the recessed portion244formed on the inclined surface242may be connected to each other by a through hole which is formed in the spacer protruding portion240in a penetrating manner in the X-axis direction.

[3.2 Description of Positional Relationship Between Two Intermediate Spacers201]

Next, the positional relationship between two intermediate spacers201will be described.FIG. 5is a side view illustrating the positional relationship between two intermediate spacers201according to the present exemplary embodiment. Specifically,FIG. 5is a view of the configuration where the energy storage device100is sandwiched between two intermediate spacers201when viewed from the Y-axis minus direction.

As illustrated inFIG. 5, two intermediate spacers201are arranged on both sides of the energy storage device100in the X-axis direction. The intermediate spacer201arranged on the X-axis minus direction side of the energy storage device100is also referred to as a first spacer200a, and the intermediate spacer201arranged on the X-axis plus direction side of the energy storage device100is also referred to as a second spacer200b. That is, the first spacer200aand the second spacer200bare arranged so as to sandwich the energy storage device100in the X-axis direction (first direction).

The spacer body portion210, the spacer side wall portions220, the spacer bottom wall portion230and the spacer protruding portions240of the first spacer200aare also referred to as a first body portion210a, first side wall portions220a, a first bottom wall portion230aand first protruding portions240a. The first side wall portion220ais one example of the first wall portion. The spacer body portion210, the spacer side wall portions220, the spacer bottom wall portion230and the spacer protruding portions240of the second spacer200bare also referred to as a second body portion210b, second side wall portions220b, a second bottom wall portion230band second protruding portions240b. The second side wall portion220bis one example of the second wall portion. The inclined surface241of the first protruding portion240ais also referred to as a first inclined surface241a, the inclined surface242of the second protruding portion240bis also referred to as a second inclined surface242b, and the inclined surface242of the first protruding portion240ais referred to as a third inclined surface242a, and the inclined surface241of the second protruding portion240bis also referred to as a fourth inclined surface241b.

In such a configuration, the first body portion210aof the first spacer200ais arranged so as to face the energy storage device100in the X-axis direction (first direction). That is, the first body portion210ais arranged so as to face the long side surface portion111aof the container110of the energy storage device100on the X-axis minus direction side.

The first side wall portions220a(first wall portions) and the first bottom wall portion230aof the first spacer200aare arranged so as to protrude from the first body portion210atoward the second spacer200balong the energy storage device100. That is, with respect to the first side wall portions220aand the first bottom wall portion230a, parts of these portions on the X-axis plus direction side are arranged to protrude from the first body portion210atoward the second side wall portions220band the second bottom wall portion230bof the second spacer200b(toward the X-axis plus direction). With respect to the first side wall portions220aand the first bottom wall portion230a, parts of these portions on the X-axis minus direction side are arranged so as to protrude from the first body portion210atoward a side opposite to the second side wall portions220band the second bottom wall portion230bof the second spacer200b(toward the X-axis minus direction).

The second body portion210bof the second spacer200bis arranged so as to face the energy storage device100in the X-axis direction (first direction). That is, the second body portion210bis arranged so as to face the long side surface portion111aof the container110of the energy storage device100on the X-axis plus direction side.

The second side wall portions220b(second wall portions) and the second bottom wall portion230bof the second spacer200bare arranged so as to protrude from the second body portion210btoward the first spacer200aalong the energy storage device100. That is, with respect to the second side wall portions220band the second bottom wall portion230b, parts of these portions on the X-axis minus direction side are arranged so as to protrude from the second body portion210btoward the first side wall portions220aand the first bottom wall portion230aof the first spacer200a(toward the X-axis minus direction). With respect to the second side wall portions220band the second bottom wall portion230b, parts of these portions on the X-axis plus direction side are arranged so as to protrude from the second body portion210btoward a side opposite to the first side wall portions220aand the first bottom wall portion230aof the first spacer200a(toward the X-axis plus direction).

In this manner, each of the first spacer200aand the second spacer200bis formed so as to cover the entire surface of one long side surface portion111a, substantially halves of both short side surface portions111b, and a substantially half of the bottom surface portion111cof the container110of the energy storage device100. With such a configuration, the first spacer200aand the second spacer200bthat sandwich the energy storage device100cover substantially the entire surfaces of both long side surface portions111a, both short side surface portions111b, and the bottom surface portion111cof the energy storage device100.

The first protruding portions240aof the first spacer200aare arranged so as to protrude from the first side wall portion220ain the Z-axis minus direction (the second direction intersecting with the first direction). In the same manner, the second protruding portions240bof the second spacer200bare arranged so as to protrude from the second side wall portions220bin the Z-axis minus direction (second direction).

The first protruding portion240ahas a spaced-apart portion250awhere a distance between the first protruding portion240aand the second protruding portion240bis larger than a distance between the first side wall portion220aand the second side wall portion220bin the X-axis direction (first direction). In the present exemplary embodiment, the first side wall portion220aand the second side wall portion220bare disposed close to each other in a state where a substantially uniform slight gap is formed over the entire length in the Z-axis direction such that the first side wall portion220aand the second side wall portion220bcover substantially the entire surface of the short side surface portion111bof the container110of the energy storage device100. The first side wall portion220aand the second side wall portion220bmay be arranged such that the first side wall portion220aand the second side wall portion220bare partially or wholly brought into contact with each other. The first protruding portion240aand the second protruding portion240bare formed such that a distance between the first protruding portion240aand the second protruding portion240bis gradually expanded in the Z-axis minus direction from the first side wall portion220aand the second side wall portion220b. With such a configuration, as a whole, the distance between the first protruding portion240aand the second protruding portion240bis larger than the distance between the first side wall portion220aand the second side wall portion220b. That is, the entirety of the first protruding portion240aforms the spaced-apart portion250a.

The distance between the first protruding portion240aand the second protruding portion240bis a distance between an end edge of the first protruding portion240aon the X-axis plus direction side and an end edge of the second protruding portion240bon the X-axis minus direction side (that is, a length of a line segment parallel to the X-axis direction which connects both end edges). The same applies to the distance between the protruding portions (or spaced-apart portions) described hereinafter.

Accordingly, the spaced-apart portion250a(the first protruding portion240a) has a first inclined surface241athat is inclined in a direction that the first inclined surface241ais disposed away from the second protruding portion240b(a distance between the first inclined surface241aand the second protruding portion240bis increased) as the first inclined surface241ais disposed away from the first side wall portion220a. The spaced-apart portion250a(the first protruding portion240a) has the third inclined surface242aon a surface thereof opposite to the second protruding portion240b. The third inclined surface242ais inclined in a direction that the third inclined surface242aapproaches the second protruding portion240bas the third inclined surface242ais disposed away from the first side wall portion220a. The spaced-apart portion250a(the first protruding portion240a) has a recessed portion243recessed in a direction away from the second protruding portion240b, and has a recessed portion244recessed in a direction approaching the second protruding portion240b.

Also with respect to the second protruding portion240b, in the same manner, in the X-axis direction (the first direction), the second protruding portion240bhas a spaced-apart portion250bwhere the distance between the second protruding portion240band the first protruding portion240ais larger than the distance between the first side wall portion220aand the second side wall portion220b. The entirety of the second protruding portion240balso forms the spaced-apart portion250b.

Accordingly, the spaced-apart portion250b(the second protruding portion240b) has a second inclined surface242bthat is inclined in a direction that the second inclined surface242bis disposed away from the spaced-apart portion250a(a distance between the second inclined surface242band the spaced-apart portion250ais increased) as the second inclined surface242bis disposed away from the second side wall portion220b. The spaced-apart portion250b(the second protruding portion240b) has the fourth inclined surface241bon a surface thereof on a side opposite to the spaced-apart portion250awhere the fourth inclined surface241bis inclined in a direction that the fourth inclined surface241bapproaches the spaced-apart portion250aas the fourth inclined surface241bis disposed away from the second side wall portion220b. The spaced-apart portion250b(the second protruding portion240b) has the recessed portion244recessed in the direction away from the spaced-apart portion250a, and the recessed portion243recessed in the direction approaching the spaced-apart portion250a.

When the distance (gap) between the first side wall portion220aand the second side wall portion220bis not uniform over the Z-axis direction, as the distance between the first side wall portion220aand the second side wall portion220bdescribed above, the distance at the position closest to the first protruding portion240aand the second protruding portion240bcan be adopted. That is, it is sufficient that the distance between the spaced-apart portion250aand the spaced-apart portion250bbe larger than the distance (gap) between the first side wall portion220aand the second side wall portion220bat the position closest to the first protruding portion240aand the second protruding portion240b. The spaced-apart portions described hereinafter are also defined in the same manner.

[3.3 Explanation of Configuration of End Spacer202and Positional Relationship with Intermediate Spacer201]

Next, the configuration of the end spacer202and the positional relationship between the intermediate spacer201and the end spacer202will be described.FIG. 6is a side view illustrating the configuration of the end spacer202according to the present exemplary embodiment and the positional relationship between the intermediate spacer201and the end spacer202. Specifically,FIG. 6is a view of a configuration in which the energy storage device100is sandwiched between the intermediate spacer201and the end spacer202when viewed from the Y-axis minus direction.

As illustrated inFIG. 6, in the same manner as the intermediate spacer201, the end spacer202has: a spacer body portion210; a spacer side wall portion220; a spacer bottom wall portion230; and a spacer protruding portion240. The end spacer202is arranged in place of the second spacer200binFIG. 5. Accordingly, the end spacer202is also referred to as a second spacer200c. That is, the first spacer200aand the second spacer200care arranged so as to sandwich the energy storage device100in the X-axis direction (first direction). Accordingly, the spacer body portion210, the spacer side wall portions220, the spacer bottom wall portion230and the spacer protruding portions240of the second spacer200care also referred to as a second body portion210c, second side wall portions220c, a second bottom wall portion230cand second protruding portions240c. The second side wall portion220cis an example of the second wall portion.

The second body portion210chas substantially the same configuration as the second body portion210bof the second spacer200bdescribed above. The second side wall portions220cand the second bottom wall portion230chave substantially the same configuration as the parts of the second side wall portions220band the second bottom wall portion230bof the second spacer200bon the X-axis minus direction side.

The second protruding portion240cis arranged so as to protrude from the second side wall portion220cin the Z-axis minus direction (second direction). Specifically, in the same manner as the second protruding portion240bof the second spacer200bdescribed above, the second protruding portion240cprotrudes in the Z-axis minus direction from both end portions of the second bottom wall portion230cin the Y-axis direction, and extend in the Y-axis direction. Unlike the second protruding portion240b, the second protruding portion240cis a protruding portion having a rectangular shape as viewed from the Y-axis direction where the second protruding portion240chas a smaller width in the X-axis direction than the second side wall portion220c. That is, the second protruding portion240chas a side surface241cparallel to the YZ plane on the surface on the X-axis plus direction side, and has a side surface242cparallel to the YZ plane on the surface on the X-axis minus direction side. The side surface242cis formed with a rectangular recessed portion245that is recessed in the X-axis plus direction (direction away from the spaced-apart portion250a). The second protruding portion240cmay be formed with a through hole that penetrates the second protruding portion240cin the X-axis direction in place of the recessed portion245.

In such a configuration, the second protruding portion240chas the spaced-apart portion250cwhere the distance between the second protruding portion240cand the first protruding portion240ais larger than the distance between the first side wall portion220aand the second side wall portion220cin the X-axis direction (first direction). That is, the entirety of the second protruding portion240cforms the spaced-apart portion250c. The spaced-apart portion250chas a shape recessed from the second side wall portion220cin the X-axis plus direction. Accordingly, it is safe to say that the spaced-apart portion250chas a recessed portion recessed in the direction away from the spaced-apart portion250a.

[3.4 Description of Distance Between Spaced-Apart Portions Disposed Adjacent to Each Other]

Next, the description is made with respect to the distance between the spaced-apart portions (spaced-apart portion250aand the spaced-apart portion250bor250c) of the protruding portions disposed adjacent to each other (first protruding portion240aand second protruding portion240bor240c).FIG. 14is a view illustrating the distance between the spaced-apart portions of the spacer protruding portions240in the two spacers200that sandwich the energy storage device100. InFIG. 14, as an example, a case is illustrated where a profile of the space between the spaced-apart portions when the space is projected from the Y-axis direction is a rectangular shape (rectangle) (a case illustrated inFIG. 7described later).

A height (a liquid column height) h′ of a liquid (water or the like) that creeps up between the spaced-apart portions of the protruding portions disposed adjacent to each other due to a capillary phenomenon is determined based on a balance between a length of an interface between wall surfaces of the spaced-apart portions with which the liquid is brought into contact, a force Fythat acts in the vertical direction due to a surface tension σ, and gravity W that acts on the liquid column. That is, assuming that the lengths b of the spaced-apart portions in the Y-axis direction (seeFIG. 14) are equal, the smaller an area of the profile of the space between the spaced-apart portions when the space is projected in the Y-axis direction, the higher the liquid column height h′ becomes.

In other words, this implies that, assuming that the profile has the same shape, the smaller the distance a between the spaced-apart portions (seeFIG. 14), the larger the liquid column height h′ becomes. Alternatively, this implies that assuming that the distance a between the spaced-apart portions is the same, the liquid column height h′ is gradually decreased in order that the liquid column height h′ is the largest when the profile is a triangle (a′=0) as illustrated inFIG. 5. Then, the liquid column height h′ when the profile is a trapezoid (a>a′) illustrated inFIG. 8described later follows. Then, the liquid column height h′ when the profile is a rectangular shape (a=a′) illustrated inFIG. 7described later follows. In the drawing, symbol a′ indicates a distance between upper end portions of the spaced-apart portions (seeFIG. 14). That is, assuming that a length (height) h of the spaced-apart portion in the Z-axis direction (seeFIG. 14) is the same, by studying the case where the profile is a triangle, it is considered that the liquid column height h′ becomes maximum. Accordingly, assuming the distance a between the spaced-apart portions as a base of the triangle, when the spaced-apart portions are spaced apart from each other more than a, the relationship between the height h of the spaced-apart portion and the liquid column height h′ becomes h>h′ and hence, theoretically, there is no possibility that creeping liquid (water or the like) reaches the spacer bottom wall portion230of the spacer.

However, when the profile is a triangle or a trapezoid, a length of an interface changes according to a liquid column height and hence, the calculation is complicated. Accordingly, the case is studied by assuming the distance a between the spaced-apart portions at the base of the triangle as the length of the interface. This study of the case is equal to the study of the case where the profile is assumed as a rectangle. However, a force Fythat acts in the vertical direction is proportional to the length of the interface and hence, the force Fycan be estimated to the maximum by studying the case where the profile is a rectangle. When the profile is a triangle or a trapezoid, a wall surface of the spaced-apart portion is not vertical and forms an inclined surface. However, a force Fythat acts in the vertical direction becomes maximum when the profile is a rectangle where the wall surface is vertical. Accordingly, by studying the case where the profile is a rectangle, the force Fycan be estimated to the maximum. That is, by studying the case where the profile is a rectangle, the calculation of a force Fythat acts in the vertical direction can be estimated to the maximum. On the other hand, the gravity W that acts on a liquid column becomes minimum when the profile is a triangle. Accordingly, by studying both cases, the liquid column height h′ can be estimated to the maximum.

Next, the steps of calculating the distance a between the spaced-apart portions in the X-axis direction will be described. A force that acts between a liquid surface to which a liquid such as water generated in the energy storage apparatus10due to dew condensation or the like creeps up and a wall surface that forms the spaced-apart portion is determined based on a length of an interface between the liquid surface and the wall surface and a surface tension. The study of a force Fythat acts in the vertical direction may be made based on the case where the profile is a rectangle when the space between the spaced-apart portions is projected in the Y-axis direction. Accordingly, a following formula is established.

In Formula 2, a is a distance between the spaced-apart portions in the X-axis direction, b is a length of the spaced-apart portion in the Y-axis direction, and σ is a surface tension when a liquid (water or the like) that creeps up between the spaced-apart portions is brought into contact with air, θ is a contact angle between a wall surface of the spaced-apart portion and the liquid.

Although there are no wall surfaces at both end portions of a space between the spaced-apart portions in the Y-axis direction, a higher liquid column height h′ can be estimated by studying a case where the space between the spaced-apart portions is a closed space by assuming that there exist wall surfaces which are contiguous with the wall surfaces of the spaced-apart portions. In this case, the distance a between the spaced-apart portions in the X-axis direction can be studied under the maximum condition.

On the other hand, the gravity W that acts on a liquid column between the spaced-apart portions is determined based on a volume and density of a liquid (water or the like) that creeps up between the spaced-apart portions and the gravitational acceleration. The gravity can be studied preferably in the case where the profile when the space between the spaced-apart portions is projected from the Y-axis direction is a triangle. Accordingly, assuming that the length (height) h of the spaced-apart portion in the Z-axis direction and the height (liquid column height) h′ of a liquid (water, or the like) that creeps up between the spaced-apart portions are equal, the following Formula 3 is established.

In Formula 3, g is the gravitational acceleration, and p is the density of a liquid (water or the like) that creeps up between the spaced-apart portions.

Because the force Fyand the gravity W balance each other, the following Formula 4 is established.

By transforming this Formula 4, the following Formula 5 is obtained.

That is, the following Formula 6 is derived.

That is, it is desirable that the above-mentioned formulae are satisfied in the case where, the distance between the first protruding portion of the first spacer and the second protruding portion of the second spacer in the X-axis direction (first direction) at the spaced-apart portion is set as a, the length of the spaced-apart portion in the Y-axis direction (the third direction that intersects with the first direction and the second direction) is set as b, the length (height) of the spaced-apart portion in the Z-axis direction (second direction) is set as h, a surface tension when a liquid (water or the like) that is disposed between the first protruding portion and the second protruding portion is brought into contact with air is set as σ, a contact angle between a wall surface of the spaced-apart portion and the liquid is set as θ, the density of the liquid is set as ρ, and the gravitational acceleration is set as g. As a result, the relationship between the length (height) h of the spaced-apart portion in the Z-axis direction (second direction) and the height (liquid column height) h′ of the liquid (water or the like) that creeps up between the spaced-apart portions never fails to become h>h′. Accordingly, theoretically, there is no possibility that a creeping liquid (water or the like) reaches the spacer bottom wall portion230.

[4 Description of Advantageous Effects]

As described above, according to the energy storage apparatus10according to the present exemplary embodiment of the present invention, the first spacer200aincludes the first side wall portion220a(first wall portion) protruding toward the second spacer200balong the energy storage device100and the first protruding portion240aprotruding from the first side wall portion220a. The second spacer200bincludes the second side wall portion220b(second wall portion) protruding toward the first side wall portion220aalong the energy storage device100, and the second protruding portion240bprotruding from the second side wall portion220b. The first protruding portion240aincludes the spaced-apart portion250awhere the distance between the first protruding portion240aand the second protruding portion240bis larger than the distance between the first side wall portion220aand the second side wall portion220b. In this manner, the first protruding portion240aand the second protruding portion240bare formed on the first spacer200aand the second spacer200b, and the spaced-apart portion250aof the first protruding portion240ais formed such that the distance between the first protruding portion240aand the second protruding portion240bis larger than the distance between the first side wall portion220aand the second side wall portion220b. As a result, when a liquid such as water enters between the first protruding portion240aand the second protruding portion240bfrom above, the liquid easily falls at the position of the spaced-apart portion250a. On the other hand, it is difficult for a liquid such as water from below to creep up at the position of the spaced-apart portion250aand hence, it is difficult for the liquid to be accumulated between the first protruding portion240aand the second protruding portion240b. Accordingly, it is possible to prevent the liquid from being accumulated between the first protruding portion240aand the second protruding portion240band hence, it is possible to prevent the energy storage device100and an external conductive member (such as a metal plate on which the energy storage apparatus10is mounted) from becoming conductive with each other. As a result, the electrical insulation performance (insulation resistance performance and withstand voltage performance) can be improved. The same applies to the spaced-apart portion250b.

The spaced-apart portion250aof the first protruding portion240aof the first spacer200aincludes the first inclined surface241athat is inclined in the direction that the first inclined surface241ais disposed away from the second protruding portion240bof the second spacer200bas the first inclined surface241ais disposed away from the first side wall portion220a. By forming the first inclined surface241aon the spaced-apart portion250aof the first protruding portion240ain this manner, a liquid such as water is more likely to fall at the position of the spaced-apart portion250a. On the other hand, it is difficult for a liquid such as water from below to creep up at the position of the spaced-apart portion250a. As a result, a liquid is less likely to be accumulated between the first protruding portion240aand the second protruding portion240band hence, it is possible to more effectively prevent the energy storage device100and an external conductive member from being conductive with each other.

The second protruding portion240bof the second spacer200bincludes the second inclined surface242bthat is inclined in the direction that the second inclined surface242bis disposed away from the spaced-apart portion250aof the first protruding portion240aof the first spacer200aas the second inclined surface242bis disposed away from the second side wall portion220b. By forming the second inclined surface242bon the second protruding portion240bin this manner, a liquid such as water is more likely to fall at the position of the spaced-apart portion250aof the first protruding portion240a. On the other hand, it is more difficult for a liquid such as water from below to creep up at the position of the spaced-apart portion250a. As a result, a liquid is less likely to be accumulated between the first protruding portion240aand the second protruding portion240band hence, it is possible to more effectively prevent the energy storage device100and an external conductive member from being conductive with each other.

The first protruding portion240aof the first spacer200aincludes the third inclined surface242awhich is inclined in the direction that the first protruding portion240aapproaches the second protruding portion240bas the third inclined surface242ais disposed away from the first side wall portion220aon the surface of the first spacer200aopposite to the second protruding portion240bof the second spacer200b. In this manner, by forming the third inclined surface242aon the surface of the first protruding portion240aon the side opposite to the second protruding portion240b, also on the side of the first protruding portion240aopposite to the second protruding portion240b, a liquid such as water from above is likely to fall. On the other hand, it is difficult for a liquid such as water from below to creep up. As a result, the liquid is less likely to be accumulated even on the side of the first protruding portion240aopposite to the second protruding portion240band hence, it is possible to prevent the energy storage device100and the external conductive member from becoming conductive with each other. The same applies to the fourth inclined surface241bof the second protruding portion240bof the second spacer200b.

The spaced-apart portion250aof the first protruding portion240aof the first spacer200aincludes the recessed portion243recessed in the direction away from the second protruding portion240bof the second spacer200b. By forming the recessed portion243in the spaced-apart portion250aof the first protruding portion240ain this manner, a liquid such as water is more likely to fall at the position of the spaced-apart portion250a. On the other hand, it is more difficult for a liquid such as water from below to creep up at the position of the spaced-apart portion250a. As a result, a liquid is less likely to be accumulated between the first protruding portion240aand the second protruding portion240band hence, it is possible to more effectively prevent the energy storage device100and an external conductive member from being conductive with each other. The same applies to the recessed portion244of the spaced-apart portion250aand the recessed portions243and244of the spaced-apart portion250b.

The inventors of the present application have found out that, in a case where the distance between the first protruding portion240aand the second protruding portion240bat the spaced-apart portion250asatisfies the above-mentioned formula, even when a liquid such as water creeps up between the first protruding portion240aand the second protruding portion240b, the liquid does not creep up above the spaced-apart portion250a. As a result, it is possible to prevent the energy storage device100and the external conductive member from becoming conductive with each other.

The above-mentioned advantageous effects on the first spacer200aand the second spacer200bcan be applied to the first spacer200aand the second spacer200cin the same manner.

[5 Description of Modifications]

Next, a modification 1 of the above-mentioned exemplary embodiment will be described.FIG. 7is a side view illustrating the configuration of two spacers200(first spacer200dand second spacer200e) that sandwich an energy storage device100according to the modification 1 of the present exemplary embodiment. Specifically,FIG. 7is a view corresponding to a portion ofFIG. 5orFIG. 6on a minus direction side of a Z axis.

As illustrated inFIG. 7, a first spacer200daccording to the present modification includes a first protruding portion240d(a spaced-apart portion250d) in place of the first protruding portion240a(the spaced-apart portion250a) of the first spacer200ain the above-mentioned exemplary embodiment. A second spacer200eaccording to the present modification includes a second protruding portion240e(a spaced-apart portion250e) in place of the second protruding portion240bor240c(the spaced-apart portion250bor250c) of the second spacer200bor200cin the above-mentioned exemplary embodiment. Other configurations are substantially the same as the corresponding configurations in the above-mentioned exemplary embodiment and hence, the detailed description of other configurations will be omitted.

A width of a first protruding portion240d(spaced-apart portion250d) in an X-axis direction is smaller than a width of a first side wall portion220din the same manner as the second protruding portion240c(spaced-apart portion250c) of the second spacer200cin the above-mentioned exemplary embodiment. The first protruding portion240d(spaced-apart portion250d) is a rectangular protruding portion when viewed in a Y-axis direction. That is, the first protruding portion240dhas a side surface241dparallel to a YZ plane on a surface of the first protruding portion240don an X-axis plus direction, and also has a side surface242dparallel to the YZ plane on a surface of the first protruding portion240don an X-axis minus direction. In the same manner, a second protruding portion240e(a spaced-apart portion250e) is a protruding portion having rectangular shape when viewed from the Y-axis direction. A width of the second protruding portion240e(a spaced-apart portion250e) in the X-axis direction is smaller than a width of the second side wall portion220ein the X-axis direction. The second protruding portion240e(a spaced-apart portion250e) has side surfaces241eand242eon both surfaces in the X-axis direction parallel to the YZ plane.

The first protruding portion240d(the spaced-apart portion250d) has a shape recessed from the first side wall portion220din the X-axis minus direction. Accordingly, it is also safe to say that the first protruding portion240d(the spaced-apart portion250d) is recessed in the direction away from the second protruding portion240e(the spaced-apart portion250e). The same applies to the second protruding portion240e(the spaced-apart portion250e).

As described above, the energy storage apparatus according to the present modification acquires substantially the same effect as the energy storage apparatus according to the modification as described above. In particular, in this modification, a distance between the spaced-apart portion250dand the spaced-apart portion250eis set to a constant value without being narrowed over the entire length in the Z-axis direction. As a result, it is possible to further prevent a liquid such as water from being accumulated between the first protruding portion240dand the second protruding portion240e. Accordingly, it is possible to further prevent the energy storage device100and the external conductive member from being conductive from each other. By setting a distance between the spaced-apart portion250dand the spaced-apart portion250eto a fixed value, even when the distance between the spaced-apart portion250dand the spaced-apart portion250eis set smaller than a maximum distance between the spaced-apart portion250aand the spaced-apart portion250bin the above-mentioned exemplary embodiment, it is possible to prevent a liquid such as water from being accumulated between the spaced-apart portion250dand the spaced-apart portion250e.

Next, a modification 2 of the above-mentioned exemplary embodiment will be described.FIG. 8is a side view illustrating the configuration of two spacers200(a first spacer200fand a second spacer200g) that sandwich an energy storage device100according to the modification 2 of the present exemplary embodiment. Specifically,FIG. 8is a view corresponding to the portion disposed on a Z-axis minus direction side inFIG. 5orFIG. 6.

As illustrated inFIG. 8, the first spacer200faccording to the present modification has a first protruding portion240f(a spaced-apart portion2500, and the second spacer200ghas a second protruding portion240g(a spaced-apart portion250g). Other configurations are substantially the same as the corresponding configurations in the above-mentioned exemplary embodiment and hence, the detailed description of other configurations will be omitted.

A width of the first protruding portion240f(the spaced-apart portion2500in the X-axis direction is set smaller than the width of the first protruding portion240a(the spaced-apart portion250a) of the first spacer200ain the above-mentioned exemplary embodiment in the X-axis direction. That is, the spaced-apart portion250fhas: a first inclined surface241fthat is inclined in a direction that the first inclined surface241fis disposed away from the second protruding portion240gas the first inclined surface241fis disposed away from the first side wall portion220f; and a third inclined surface242fthat is inclined in a direction that the third inclined surface242fapproaches the second protruding portion240gas the third inclined surface242fis disposed away from the first side wall portion220f. A distance between the first inclined surface241fand the third inclined surface242fis smaller than the distance between the first inclined surface241aand the third inclined surface242aof the spaced-apart portion250ain the above-mentioned exemplary embodiment. The same applies to the second inclined surface242gand a fourth inclined surface241gof the second protruding portion240g(the spaced-apart portion250g).

As described above, the energy storage apparatus according to the present modification acquires substantially the same effect as the energy storage apparatus according to the modification as described above. In particular, in this modification, the maximum distance between the spaced-apart portion250fand the spaced-apart portion250gcan be increased. As a result, it is possible to further prevent a liquid such as water from being accumulated between the first protruding portion240fand the second protruding portion240g. Accordingly, it is possible to further prevent the energy storage device100and an external conductive member from becoming conductive to each other.

Next, a modification 3 of the above-mentioned exemplary embodiment will be described.FIG. 9is a side view illustrating the configuration of two spacers200(a first spacer200hand a second spacer200i) that sandwich an energy storage device100according to the modification 3 of the present exemplary embodiment. Specifically,FIG. 9is a view corresponding to a portion illustrated on a Z-axis minus direction side inFIG. 5orFIG. 6.

As illustrated inFIG. 9, in this modification, the first spacer200hhas a first protruding portion240h(a spaced-apart portion250h), and the second spacer200ihas a second protruding portion240i(a spaced-apart portion250i). Other configurations are substantially the same as the corresponding configurations in the above-mentioned exemplary embodiment and hence, the detailed description of other configurations will be omitted.

The first protruding portion240h(the spaced-apart portion250h) has a curved surface that is recessed while being curved in the X-axis minus direction on a surface of the first protruding portion240hon an X-axis plus direction side, and has a curved surface that is recessed while being curved in the X-axis plus direction on a surface of the first protruding portion240hon an X-axis minus direction side. That is, the spaced-apart portion250hhas: a first inclined surface241hhaving a curved shape that is inclined while being curved in a direction away from the second protruding portion240ias the first inclined surface241his disposed away from the first side wall portion220h; and a third inclined surface242hhaving a curved shape that is inclined while being curved in a direction approaching the second protruding portion240ias the third inclined surface242his disposed away from the first side wall portion220h. The same applies to a second inclined surface242iand a fourth inclined surface241iof the second protruding portion240i(the spaced-apart portion250i).

The first protruding portion240h(the spaced-apart portion250h) has a shape recessed in the X-axis minus direction from the first side wall portion220h. Accordingly, it is safe to say that the first protruding portion240hhas a recessed portion recessed toward a direction away from the second protruding portion240i(the spaced-apart portion250i). The same applies to the second protruding portion240i(the spaced-apart portion250i).

As described above, the energy storage apparatus according to the present modification acquires substantially the same effect as the energy storage apparatus according to the modification as described above. In particular, a distance between the spaced-apart portion250hand the spaced-apart portion250iis sharply increased. Accordingly, it is possible to more effectively prevent a liquid such as water from being accumulated between the first protruding portion240fand the second protruding portion240g. As a result, it is possible to further prevent the energy storage device100and an external conductive member from becoming conductive to each other.

Next, a modification 4 of the above-mentioned exemplary embodiment will be described.FIG. 10is a side view illustrating the configuration of two spacers200(a first spacer200jand a second spacer200k) that sandwich an energy storage device100according to the modification 4 of the present exemplary embodiment. Specifically,FIG. 10is a view corresponding to a portion inFIG. 5orFIG. 6on a Z-axis minus direction side.

As illustrated inFIG. 10, the first spacer200jin this modification has a first protruding portion240j(a spaced-apart portion250j), and a second spacer200khas a second protruding portion240k(a spaced-apart portion250k). Other configurations are substantially the same as the corresponding configurations in the above-mentioned exemplary embodiment and hence, the detailed description of other configurations will be omitted.

The first protruding portion240j(the spaced-apart portion250j) has a first inclined surface241jsubstantially equal to the first inclined surface241aof the first protruding portion240ain the above-mentioned exemplary embodiment. On the other hand, the first protruding portion240jhas a side surface242jwhich is parallel to a YZ plane instead of an inclined surface on a surface of the first protruding portion240jon an X-axis minus direction side. The same applies to a fourth inclined surface241kand a side surface242kof the second protruding portion240k(spaced-apart portion250k).

As described above, the energy storage apparatus according to the present modification acquires substantially the same effect as the energy storage apparatus according to the modification as described above. In particular, in this modification, it is sufficient to form the inclined surface on only one surface of the spaced-apart portion250jand the spaced-apart portion250k. Accordingly, the first protruding portion240jand the second protruding portion240kcan be easily formed.

Next, a modification 5 of the above-mentioned exemplary embodiment will be described.FIG. 11is a side view illustrating the configuration of two spacers200(a first spacer200land a second spacer200m) that sandwich an energy storage device100according to the modification 5 of the present exemplary embodiment. Specifically,FIG. 11is a view corresponding to a portion inFIG. 5orFIG. 6on a Z-axis minus direction side.

As illustrated inFIG. 11, in this modification, the first spacer200lhas a first protruding portion240l(a spaced-apart portion250l), and the second spacer200mhas a second protruding portion240m(a spaced-apart portion250m). Other configurations are substantially the same as the corresponding configurations in the above-mentioned exemplary embodiment and hence, the detailed description of other configurations will be omitted.

The first protruding portion240l(the spaced-apart portion250l) has a first inclined surface241lthat is substantially equal to the first inclined surface241ain the above-mentioned exemplary embodiment on a surface of the first protruding portion240lon an X-axis plus direction side. On the other hand, the first protruding portion240lhas a third inclined surface242lthat is inclined in a direction opposite to the inclined surface of the third inclined surface242aon a surface of the first protruding portion240lon an X-axis minus direction side. The same applies to a fourth inclined surface241mand a second inclined surface242mof the second protruding portion240m(the spaced-apart portion250m).

As described above, the energy storage apparatus according to the present modification acquires substantially the same effect as the energy storage apparatus according to the modification as described above. In particular, in this modification, one surface of the spaced-apart portion250land the spaced-apart portion250mis inclined in the direction opposite to the corresponding one side of the spaced-apart portion250land the spaced-apart portion250min the above-mentioned exemplary embodiment. As described above, as the shape of the spaced-apart portion, various profiles can be taken.

Next, a modification 6 of the above-mentioned exemplary embodiment will be described.FIG. 12is a top plan view illustrating the configuration of two spacers200(a first spacer200nand a second spacer200o) that sandwich an energy storage device100according to the modification 6 of the present exemplary embodiment. Specifically,FIG. 12is a plan view illustrating the configuration in a case where a state that the energy storage device100is sandwiched by two spacers200(the first spacer200nand the second spacer200o) is viewed from an upper side (a Z-axis plus direction).

As illustrated inFIG. 12, in the present modification, the first spacer200nhas a first protruding portion240n(a spaced-apart portion250n) in place of the first protruding portion240a(the spaced-apart portion250a) of the first spacer200ain the above-mentioned exemplary embodiment. In the present modification, the second spacer200ohas a second protruding portion240o(a spaced-apart portion250o) in place of the second protruding portion240bor240c(the spaced-apart portion250bor250c) of the second spacer200bor200cin the above-mentioned exemplary embodiment. Other configurations are substantially the same as the corresponding configurations in the above-mentioned exemplary embodiment and hence, the detailed description of other configurations will be omitted.

The first protruding portion240nis a protruding portion that protrudes in a Y-axis direction from a first side wall portion220n. Two first protruding portions240nare disposed corresponding to two first side wall portions220n. That is, the first protruding portion240nthat protrudes in a Y-axis plus direction is disposed with respect to the first side wall portion220nin a Y-axis plus direction, and the first protruding portion240nthat protrudes in a Y-axis minus direction is disposed with respect to the first side wall portion220non a Y-axis minus direction. Also with respect to the second protruding portion240o, in the same manner, the second protruding portion240othat protrudes in the Y-axis plus direction is disposed with respect to the second side wall portion220oin the Y-axis plus direction, and the second protruding portion240othat protrudes in the Y-axis minus direction is disposed with respect to the second side wall portion220oin the Y-axis minus direction. As described above, in this modification, the Y-axis direction, the Y-axis plus direction, or the Y-axis minus direction is an example of the second direction, and the Z-axis direction is an example of the third direction.

In the same manner as the above-mentioned exemplary embodiment, the first protruding portion240nhas a first inclined surface241non a surface of the first protruding portion240non an X-axis plus direction side in a state where the first inclined surface241nis inclined in a direction that the first inclined surface241nis disposed away from the second protruding portion240oas the first inclined surface241nis disposed away from the first side wall portion220n. On a surface of the first protruding portion240non an X-axis minus direction side, a third inclined surface242nis formed in a state where the third inclined surface242nis inclined in a direction that the third inclined surface242napproaches the second protruding portion240oas the third inclined surface242nis disposed away from the first side wall portion220n. In the same manner, on a surface of the second protruding portion240oon an X-axis minus direction side, a second inclined surface242ois formed in a state where the second inclined surface242ois inclined in a direction that the second inclined surface242ois disposed away from the first protruding portion240nas the second inclined surface242ois disposed away from the second side wall portion220o. On a surface of the second protruding portion240oon an X-axis plus direction side, a fourth inclined surface2410is formed in a state where the fourth inclined surface2410is inclined in a direction that the fourth inclined surface2410approaches the first protruding portion240nas the fourth inclined surface2410is disposed away from the second side wall portion220o.

With such a configuration, the first protruding portion240nhas a portion (a spaced-apart portion250n) where a distance between the first protruding portion240nand the second protruding portion240oin the X-axis direction is larger than a distance between the first side wall portion220nand the second side wall portion220oin the X-axis direction. The second protruding portion240ohas a portion (a spaced-apart portion250o) where a distance between the first protruding portion240nand the second protruding portion240oin the X-axis direction is larger than a distance between the first side wall portion220nand the second side wall portion220oin the X-axis direction.

As described above, the energy storage apparatus according to the present modification acquires substantially the same effect as the energy storage apparatus according to the modification as described above. In particular, in this modification, the first protruding portion240nand the second protruding portion240oprotrude in the Y-axis direction. Accordingly, even when a conductive member such as a metal plate is disposed on a side (the Y-axis direction) of the energy storage device100, it is possible to prevent the energy storage device100and the conductive member from becoming conductive to each other.

In this modification, various modifications such as the above-mentioned modifications 1 to 5 can be adopted. The first protruding portion240nand the second protruding portion240omay be provided to only one side of the first spacer200nand the second spacer200oin the Y-axis direction.

The energy storage apparatuses according to the present exemplary embodiment and the modifications of the present exemplary embodiment have been described heretofore. However, the present invention is not limited to the above-described exemplary embodiment and modifications. That is, the present exemplary embodiment and the modifications of the present exemplary embodiment are illustrative in all aspects, and are not limitative. The present invention includes all alterations which fall within the scope of claims or are considered equivalent to the present invention.

In the above-described exemplary embodiment and the modifications of the present exemplary embodiment, the first side wall portion of the first spacer is adopted as an example of the first wall portion, and the second side wall portion of the second spacer is adopted as an example of the second wall portion. However, the first bottom wall portion of the first spacer may be adopted as an example of the first wall portion, and the second bottom wall portion of the second spacer may be adopted as an example of the second wall portion. That is, the first bottom wall portion protrudes from the first body portion of the first spacer toward the second spacer along the energy storage device100, and the second bottom wall portion protrudes from the second body portion of the second spacer toward the first bottom wall portion along the energy storage device100. The first protruding portion of the first spacer protrudes from the first bottom wall portion in the Z-axis minus direction (the second direction), and the second protruding portion of the second spacer protrudes from the second bottom wall portion in the Z-axis minus direction (the second direction). The first protruding portion has the spaced-apart portion where the distance between the first protruding portion and the second protruding portion in the X-axis direction (first direction) is larger than the distance between the first bottom wall portion and the second bottom wall portion.

In the above-described exemplary embodiment and the modifications of the present exemplary embodiment, the entirety of the first protruding portion of the first spacer forms the spaced-apart portion. However, it is sufficient that at least a part of the first protruding portion has the spaced-apart portion. That is, it is sufficient that the first protruding portion has, at least at a part of the first protruding portion, the spaced-apart portion where the distance between the first protruding portion and the second protruding portion is larger than the distance between the first side wall portion220aand the second side wall portion220b. The same applies to the second protruding portion of the second spacer.

In the above-described exemplary embodiment and the modifications of the present exemplary embodiment, the first spacer and the second spacer which sandwich the energy storage device100cover substantially the entire surface of both long side surface portions111a, both short side surface portions111band the bottom surface portion111cof the energy storage device100. However, it is sufficient that the first spacer and the second spacer cover only a part of the long side surface portions111a, the short side surface portions111b, and the bottom surface portion111cwithout covering the entire surface of the long side surface portion111a, the short side surface portions111band the bottom surface portion111c.

In the above-mentioned exemplary embodiment and the modifications of the present exemplary embodiment, the description has been made on the premise that all spacers200have the above-mentioned configuration. However, some spacers200may not have the above-mentioned configuration.

In the above-mentioned exemplary embodiment and the modifications of the present exemplary embodiment, the description has been made with respect to the case where the energy storage device100and the spacer200are restrained by the end members300and the side members400. However, neither the end members300nor the side members400may be disposed in the energy storage apparatus, and the energy storage devices100and the spacers200may be housed in an exterior body (a module case).

In the above-mentioned exemplary embodiment and the modifications of the present exemplary embodiment, the plurality of energy storage apparatuses10may be stacked in the Z-axis direction.FIG. 13is a perspective view illustrating the configuration when the energy storage apparatuses10according to the modification 7 of the present exemplary embodiment are stacked in the vertical direction. Specifically,FIG. 13illustrates the configuration of a module where three energy storage apparatuses10are stacked in the vertical direction. As described above, the technique of the present invention is also effective to the module where the plurality of energy storage apparatuses10are stacked in the vertical direction. In the illustration of the energy storage apparatus10, bus bars, bus bar frames and a cover member (an upper lid) and the like are omitted.

The configurations which are formed by arbitrarily combining the respective constitutional elements which the above-mentioned exemplary embodiment and the above-mentioned modifications include also fall within the scope of the present invention.

The present invention can be realized not only as such an energy storage apparatus but also as the spacers200(the first spacer, the second spacer).

INDUSTRIAL APPLICABILITY

The present invention is applicable to an energy storage apparatus or the like that includes energy storage devices such as lithium ion secondary batteries.

DESCRIPTION OF REFERENCE SIGNS

10: energy storage apparatus100: energy storage device110: container111: container body111a: long side surface portion111b: short side surface portion111c: bottom surface portion200: spacer200a,200d,200f,200h,200j,2001,200n: first spacer200b,200c,200e,200g,200i,200k,200m,2000: second spacer201: intermediate spacer202: end spacer210: spacer body portion210a: first body portion210b,210c: second body portion220: spacer side wall portion220a,220d,220f,220h,220j,2201,220n: first side wall portion220b,220c,220e,220g,220i,220k,220m,220o: second side wall portion230: spacer bottom wall portion230a: first bottom wall portion230b,230c: second bottom wall portion240: spacer protruding portion240a,240d,240f,240h,240j,2401,240n: first protruding portion240b,240c,240e,240g,240i,240k,240m,240o: second protruding portion241,242: inclined surface241a,241f,241h,241j,2411,241n: first inclined surface241b,241g,241i,241k,241m,241o: fourth inclined surface241c,241d,241e,242c,242d,242e,242j,242k: side surface242a,242f,242h,2421,242n: third inclined surface242b,242g,242i,242m,242o: second inclined surface243,244,245: recessed portion250a,250b,250c,250d,250e,250f,250g,250h,250i,250j,250k,250l,250m,250n,250o: spaced-apart portion