JP7555006B2 - Power storage device - Google Patents

Description

This disclosure relates to an electricity storage device.

Conventionally, power storage devices having a structure in which multiple battery modules are housed in a rack are widely known. Power storage devices are installed in homes, stores, offices, factories, public facilities, etc., and store electricity generated by, for example, solar cells. Power storage devices are also used as emergency power sources in the event of a power outage. Power storage devices are often installed outdoors, and power storage devices installed outdoors are provided with a cover that covers the rack to protect the battery modules from rainwater, etc. (see, for example, Patent Documents 1 and 2).

JP 2012-74421 A JP 2017-5027 A

However, if an abnormality occurs in a cell that constitutes a battery module, high-pressure gas may be discharged from the battery module. In addition, if an electric storage device is submerged due to river flooding, high tides, tsunamis, etc., hydrogen may be generated by electrolysis of water, and the electrical equipment of the electric storage device may become an ignition source, leading to an explosion. In an electric storage device that is provided with a cover that covers the rack, if gas is generated inside the cover and the internal pressure rises, it is expected that the cover will be blown off. The purpose of the present disclosure is to provide an electric storage device that can smoothly discharge gas inside the cover when such an abnormality occurs.

The energy storage device according to one aspect of the present disclosure includes a battery module, a rack that houses the battery module, and a cover that covers the rack. The cover is provided with an exhaust valve that opens outward without coming off the cover to release pressure when the pressure inside the cover exceeds a predetermined threshold.

According to the electricity storage device of the present disclosure, even if an abnormality occurs in which gas is generated inside the cover and the internal pressure rises, the gas inside the cover can be smoothly discharged. According to the electricity storage device of the present disclosure, the gas is discharged by opening the exhaust valve portion outward, so it is possible to prevent the cover from being blown off.

1 is a front perspective view of an electric storage device according to an embodiment; 1 is an exploded perspective view of a power storage device according to an embodiment, as viewed from the rear; FIG. 2 is an exploded perspective view of a cover according to an embodiment; 2 is a perspective view illustrating a state in which a second side cover and a top cover are removed from the power storage device according to the embodiment; FIG. 1 is a perspective view illustrating a state in which an exhaust valve portion of an electricity storage device according to an embodiment is open outward;

The following describes in detail an example of an embodiment of a power storage device with reference to the drawings. The embodiment described below is merely an example, and the present disclosure is not limited to the embodiment described below. In addition, it is anticipated from the beginning that multiple embodiments and their modified examples described below may be selectively combined.

Figure 1 is a front perspective view of an energy storage device 10 according to an embodiment. Figure 2 is an exploded rear perspective view of the energy storage device 10. As shown in Figures 1 and 2, the energy storage device 10 includes a battery module 11, a rack 20 that houses the battery module 11, and a cover 30 that covers the rack 20. The energy storage device 10 generally includes a plurality of battery modules 11. In this embodiment, two battery modules 11 are arranged side by side in two tiers, and a total of four battery modules 11 are housed in the rack 20.

For ease of explanation, in this specification, when the energy storage device 10 is installed, the direction along the vertical direction is referred to as the "up-down direction", the horizontal direction perpendicular to the up-down direction in which the battery modules 11 are lined up is referred to as the "horizontal direction", and the direction perpendicular to the up-down direction and the horizontal direction is referred to as the "front-rear direction". In addition, the side of the wiring cover 35 described below is referred to as the "rear", and the opposite side is referred to as the "front".

The energy storage device 10 further includes a control unit 40 housed in the rack 20 and a unit cover 41 that covers the control unit 40. The control unit 40 is composed of electronic devices such as a microcomputer including a processor, memory, input/output interface, etc., a circuit board, fuses, and breakers, and has the function of monitoring the state of the battery module 11. The control unit 40 may detect abnormalities in the battery module 11 based on information from a voltage sensor, a current sensor, a temperature sensor, etc. installed in the battery module 11, and may also calculate the state of charge (SOC) of the battery module 11.

The control unit 40 is housed higher on the rack 20 than the battery modules 11, and is surrounded by a unit cover 41. The unit cover 41 covers the top of the control unit 40 to protect it from condensation water and to prevent tools and the like from coming into contact with the control unit 40 during installation, maintenance, and the like. The unit cover 41, for example, prevents condensation water from dripping onto the control unit 40 and suppresses the occurrence of condensation on the control unit 40.

The energy storage device 10 is installed, for example, in a house. The energy storage device 10 may be installed indoors, but is generally installed outdoors on a concrete foundation. As described above, the energy storage device 10 includes a cover 30 that covers the rack 20, and is configured to prevent rainwater and the like from entering the rack 20 that houses the battery module 11 and the control unit 40. Note that the facility in which the energy storage device 10 is installed is not limited to a house, and may be a public facility such as a school, library, or hospital, a store, an office, a factory, or a power generation facility such as a solar power plant.

The energy storage device 10 is connected to a power source and electrical equipment via, for example, a power conditioner (hereinafter referred to as "power conditioner"). When the energy storage device 10 is installed in a house, examples of electrical equipment include lighting, water heaters, air conditioners, televisions, personal computers, and refrigerators. The electrical equipment is generally connected to the power conditioner via a distribution board. The distribution board is also connected to a commercial power system. One example of a power source is a solar power generation device. The power conditioner, for example, supplies power generated by the solar power generation device to the energy storage device 10, converts the DC power of the energy storage device 10 to AC power and supplies it to the distribution board, and controls the charging and discharging of the energy storage device 10.

The appearance of the energy storage device 10 depends mainly on the shape of the cover 30, and is generally a roughly rectangular parallelepiped. The energy storage device 10 has a rectangular parallelepiped appearance with, for example, the vertical length > the front-to-rear length > the horizontal length. In this embodiment, a box-shaped cover 30 with an open bottom is fixed to the bottom plate 24 of the rack 20. Gaskets may be installed in the gaps in the cover 30, etc., and a sheet may be placed on the inner surface of the cover 30 to deal with condensation water.

Below, each component of the energy storage device 10 will be described in detail, particularly the exhaust valve portion 36 of the cover 30 and the related configuration, with reference to Figures 3 to 5 as appropriate in addition to Figures 1 and 2.

[Battery module]
The battery module 11 has a rectangular parallelepiped appearance with the length in the front-rear direction > the length in the up-down direction > the length in the lateral direction. The battery module 11 includes a battery holder 12 that houses a plurality of unit cells. The type of unit cell is not particularly limited, but a suitable example is a lithium ion battery. The shape of the unit cell is also not particularly limited, but in this embodiment, a cylindrical battery is used. The battery holder 12 is formed with a plurality of cylindrical storage sections that house the cylindrical batteries.

Connector sections 13 are provided on the front and rear of the battery module 11 to which wiring (not shown) is connected. For example, each battery module 11 is connected in series with the other adjacent battery modules 11 via wiring. The wiring also extends above the rack 20 and is connected to the control unit 40, and is pulled out from the rear of the energy storage device 10 to the outside and connected to the power conditioner. Space is provided between the front and rear of the battery module 11 and the cover 30 for routing the wiring.

The battery module 11 has a frame 14 that is attached to the outside of the battery holder 12. The battery module 11 is fixed to the rack 20 using module fixing brackets 27 that connect the frame 14 to the vertical frame 22 of the rack 20. The module fixing brackets 27 are provided, for example, at the front and rear of the battery module 11, and connect the battery modules 11 arranged in the horizontal direction to each other and fix the two battery modules 11 to the rack 20. In this embodiment, as described above, a total of four battery modules 11 are arranged in two stages.

[rack]
The rack 20 includes an inner frame 21 including vertical frames 22 and horizontal frames 23, and a bottom plate 24 that constitutes the bottom surface of the rack 20. The rack 20 also includes a shelf plate 25 for supporting the upper battery module 11, and a shelf plate 26 for supporting the control unit 40. The bottom plate 24 and the shelf plates 25, 26 are plate-like members that are rectangular in plan view. The rack 20 is generally made of steel plate, and has a structure in which a total of four vertical frames 22 are erected, one at each of the four corners of the bottom plate 24, and the vertical frames 22 are connected to each other by a plurality of horizontal frames 23 that extend along the horizontal direction and the front-rear direction.

A cover 30 with an open bottom is placed over the rack 20 and secured in place using screws or the like. In this embodiment, the lower end of the cover 30 is secured to the bottom plate 24 with screws. When replacing the battery modules 11 or the like, the cover 30 is removed, but the cover 30 can be removed as a unit by removing the screws fastened to the bottom plate 24 and pulling the cover 30 upward, allowing for easy maintenance.

It is also preferable that legs 28 are attached to the bottom plate 24 of the rack 20. The legs 28 are attached, for example, one each to the front and rear of the bottom plate 24, and are placed and fixed on a concrete foundation. The legs 28 form a gap between the foundation and the bottom plate 24, and raise the bottom of the rack 20. This makes it difficult for the battery modules 11 to become flooded. Since the legs 28 are easily exposed to water, they may be made of a steel plate that is more corrosion-resistant than the inner frame 21. The legs 28 are formed, for example, by bending a steel plate.

[cover]
FIG. 3 is an exploded perspective view of the cover 30, and the exhaust valve portion 36 is hatched with dots. As shown in FIGS. 1 to 3, the cover 30 includes a side cover 31 that covers the side of the rack 20, and a top cover 34 that covers the top of the rack 20. The cover 30 has a structure in which one opening of the side cover 31 formed in a square tube shape is closed by the top cover 34 that is rectangular in plan view, and is generally made of a metal plate such as a steel plate. The top cover 34 is, for example, screwed to the upper end of the side cover 31, and may be removed from the side cover 31 during maintenance. An opening for pulling out wiring is formed on the rear surface of the side cover 31, and a wiring cover 35 is fixed to cover the opening.

The cover 30 is placed over the rack 20 from above to cover the entire rack 20 and prevent the intrusion of rainwater, dust, etc. into the rack 20. In order to reduce the size of the energy storage device 10, the side cover 31 is designed to be small enough to accommodate the rack 20, and for example, the side cover 31 is placed close to the side of the battery module 11. To ensure space for wiring, inside the energy storage device 10, which is inside the cover 30, there is a larger space in front and behind the battery module 11 than on the sides.

The side cover 31 includes a first side cover 32 that covers three sides of the rack 20, and a second side cover 33 that is fixed to the first side cover 32 and formed in a flat plate shape. The first side cover 32 and the second side cover 33, for example, have the same vertical length. The first side cover 32 is formed by bending a metal plate so as to cover the entire front, rear, and left side of the sides of the rack 20, and to cover a portion of the front and rear sides of the right side.

The second side cover 33 is formed in a flat plate shape so as to cover the portion of the right side of the rack 20 that is not covered by the first side cover 32. The second side cover 33 has, for example, a rectangular shape in a side view, and is longer in the up-down direction than in the front-rear direction of the energy storage device 10. Here, flat plate shape means that the overall shape is a generally flat plate, and for example, most of the second side cover 33 (80% or more) is formed flat. In this embodiment, the upper end of the side cover 31 is recessed inward to form a groove shape. By forming such a groove, it becomes difficult for rainwater, etc. to penetrate.

The cover 30 is provided with an exhaust valve section 36 that opens outward to release pressure without coming off the cover 30 when the pressure inside the cover 30 exceeds a predetermined threshold. By providing the exhaust valve section 36, even if an abnormality occurs such as gas being generated inside the cover 30 and the internal pressure rising, the gas inside the cover 30 can be smoothly discharged, and the cover 30 can be prevented from being blown off. In this embodiment, since the top cover 34 is screwed to the upper end of the side cover 31, the predetermined threshold at which the exhaust valve section 36 opens is set to a value at least lower than the pressure at which the top cover 34 is blown off. When the pressure inside the cover 30 does not exceed the predetermined threshold, the exhaust valve section 36 functions as a normal cover that prevents the intrusion of rainwater, etc.

The exhaust valve section 36 is preferably provided on the side cover 31. If the exhaust valve section 36 is provided on the side cover 31, the power storage device 10 can be placed near a wall so that the exhaust valve section 36 faces the wall. In this case, it is possible to prevent gas released from the exhaust valve section 36 from hitting a person directly. The exhaust valve section 36 may be provided on multiple surfaces of the cover 30, but from the viewpoint of regulating the exhaust direction of gas, it is preferable that the exhaust valve section 36 be provided on one surface of the side cover 31. In this embodiment, one exhaust valve section 36 is provided only on the second side cover 33, which is one surface of the side cover 31.

The second side cover 33 has a fixing part with the first side cover 32 at a part spaced a predetermined distance downward from its upper end, and the part from the upper end of the second side cover 33 to the fixing part forms an exhaust valve part 36 that opens outward with the fixing part as a fulcrum. The second side cover 33 is formed in a flat plate shape, and therefore has a smaller bending rigidity than the first side cover 32, which is formed to cover three sides of the rack 20. The part located on the upper end side of the second side cover 33 from the fixing part is not fixed anywhere, and is not covered by the rib 39 of the top cover 34, which will be described later. Therefore, the upper part of the second side cover 33 opens outward with the fixing part as a fulcrum when the pressure inside the cover 30 rises.

As described above, the fixing portion of the first side cover 32 and the second side cover 33 is formed at a portion spaced a predetermined length downward from the upper end of the second side cover 33. The longer this predetermined length is, the larger the exhaust valve portion 36 becomes, and generally the easier it is for the exhaust valve portion 36 to open; however, the length is limited to a certain extent in consideration of the strength of the cover 30, etc. One suitable example of the predetermined length is 5% to 50% of the vertical length of the second side cover 33, and more preferably 10% to 30%.

The second side cover 33 overlaps the outside of the first side cover 32 at both ends in the width direction, and is fixed to the first side cover 32 by fastening rivets 37 to the overlapping portions. In this case, the portion (fixed portion) to which the rivet 37 is fastened that is closest to the upper end of the second side cover 33 becomes the fulcrum when the exhaust valve portion 36 opens. Note that, although the fixed portion is formed by the rivet 37 in the example shown in FIG. 3, the configuration of the fixed portion is not limited to this, and it may be formed by using a screw instead of the rivet 37, or by welding.

The fixing parts that serve as fulcrums when the exhaust valve part 36 opens are preferably formed at approximately the same height on both sides in the width direction of the second side cover 33. Here, approximately the same height does not only mean the exact same height, but also includes the case where the fixing parts are considered to be substantially the same height, such as when the inclination of the line connecting the fixing parts with respect to a line parallel to the front-rear direction of the energy storage device 10 is within 5°. In this case, rivets 37 are fastened to both ends in the width direction of the second side cover 33 so as to be aligned along the front-rear direction. Fastening the rivets 37 in this way to align the height of the fulcrums makes it easier for the exhaust valve part 36 to open.

The top cover 34 has a top plate 38 that covers the top of the rack 20, and ribs 39 that are erected on the periphery of the top plate 38, extend downward, and are positioned on the outside of the first side cover 32. The formation of the ribs 39 increases the rigidity of the top cover 34, and the positioning of the ribs 39 to cover the outside of the upper end of the first side cover 32 also increases the load-bearing capacity of the first side cover 32. The ribs 39 are formed, for example, to a length sufficient to cover the entire groove-shaped portion formed on the upper end of the first side cover 32.

On the other hand, the ribs 39 are not formed in the portions that overlap with the second side cover 33, or are shorter in length than the other portions, and are formed so as not to cover the outside of the second side cover 33. By arranging the ribs 39 in this way so as not to interfere with the second side cover 33, the ribs 39 do not get in the way when the exhaust valve portion 36 opens. Also, the portions of the top cover 34 where the ribs 39 are not formed, or the portions that are shorter in length than the other portions, have lower rigidity than the portions where the ribs 39 are longer, and are preferentially deformed when the pressure inside the cover 30 increases.

Figure 4 is a perspective view showing the state in which the second side cover 33 and the top cover 34 of the energy storage device 10 have been removed. As shown in Figure 4, an opening 42 facing the exhaust valve portion 36 is formed in the unit cover 41 that covers the control unit 40. The opening 42 is preferably formed on the side of the unit cover 41 at a position facing the exhaust valve portion 36. The opening 42 is, for example, smaller than the exhaust valve portion 36 and is formed in a range facing the exhaust valve portion 36.

The opening 42 of the unit cover 41 has the function of restricting the direction in which the gas is blown out. For example, if the storage device 10 is submerged in water, hydrogen is generated by electrolysis of water, and the electronic devices of the control unit 40, such as a breaker, may become an ignition source and lead to an explosion. At this time, since the control unit 40 is surrounded by the unit cover 41, the blast blows out from the only open opening 42. The blast released from the opening 42 then opens the exhaust valve portion 36 opposite the opening 42 outward, and is discharged to the outside of the storage device 10. By forming the opening 42 in the unit cover 41 that covers the control unit 40, which may be an ignition source, the direction in which the gas is blown out can be restricted, and the gas can be discharged smoothly.

Figure 5 is a perspective view showing the exhaust valve portion 36 open outward. As shown in Figure 5, according to the power storage device 10 having the above configuration, when an abnormality occurs such as gas generation in the cover 30 causing an increase in internal pressure, the exhaust valve portion 36 opens outward, and the gas inside the cover 30 can be smoothly discharged. The exhaust valve portion 36 does not come off the first side cover 32 because it opens by rotating outward about the fixed portion with the first side cover 32 to which the rivet 37 is fastened as a fulcrum. Also, in the example shown in Figure 5, the shortened portion of the rib 39 of the top cover 34 is deformed so as to be convex outward, widening the opening of the cover 30 formed by the opening of the exhaust valve portion 36.

As described above, the energy storage device 10 having the above configuration can smoothly discharge gas from inside the cover 30, preventing the cover 30 from being blown off.

The above embodiment may be appropriately modified in design without impairing the purpose of the present disclosure. For example, in the above embodiment, the side cover 31 composed of the first side cover 32 and the second side cover 33 is illustrated, but the side cover may be composed of four metal plates, and the exhaust valve portion may be formed in one of them. In addition, in order to make the exhaust valve portion 36 easier to open, for example, a linear groove or crease line may be formed so as to connect the rivets 37 (fixing portion) fastened to both ends in the width direction of the second side cover 33. In this case, the exhaust valve portion 36 becomes easier to open so as to rotate around the groove or crease line as a rotation axis. In addition, the top cover 34 may not be formed with the rib 39, and for example, a thin-walled portion may be formed near the exhaust valve portion 36 of the top plate 38 to reduce the rigidity near the exhaust valve portion 36.

10 Energy storage device, 11 Battery module, 12 Battery holder, 13 Connector section, 14 Frame, 20 Rack, 21 Inner frame, 22 Vertical frame, 23 Horizontal frame, 24 Bottom plate, 25, 26 Shelf, 27 Module fixing bracket, 28 Legs, 30 Cover, 31 Side cover, 32 First side cover, 33 Second side cover, 34 Top cover, 35 Wiring cover, 36 Exhaust valve section, 37 Rivet, 38 Top plate, 39 Rib, 40 Control unit, 41 Unit cover, 42 Opening

Claims (4)

A battery module;
A rack that houses the battery module;
A cover for covering the rack;
Equipped with
The cover is provided with an exhaust valve portion that opens outwardly without coming off the cover to release pressure when the pressure inside the cover exceeds a predetermined threshold value ,
the cover includes a first side cover that covers the front, rear, left side, and part of the front and rear sides of the right side of the rack, and a second side cover that is formed in a flat plate shape so as to cover a part of the right side of the rack that is not covered by the first side cover, and has a side cover that covers the side of the rack;
a fixing portion for fixing to the first side cover is provided at a portion of the second side cover that is a predetermined distance downward from an upper end of the second side cover, and the portion of the second side cover from the upper end to the fixing portion forms the exhaust valve portion that opens outward with the fixing portion as a fulcrum . The power storage device according to claim 1 , wherein the cover further includes a top cover that covers an upper portion of the rack. A battery module;
A rack that houses the battery module;
A cover for covering the rack;
Equipped with
The cover is provided with an exhaust valve portion that opens outwardly without coming off the cover to release pressure when the pressure inside the cover exceeds a predetermined threshold value,
The cover includes a first side cover that covers three sides of the rack and a second side cover formed in a flat plate shape, the side cover covering the side of the rack, and a top cover that covers an upper part of the rack,
a fixing portion for fixing to the first side cover is provided at a portion of the second side cover that is spaced downward from an upper end of the second side cover by a predetermined distance, and a portion of the second side cover from the upper end to the fixing portion constitutes the exhaust valve portion that opens outward with the fixing portion as a fulcrum;
the top cover has a top plate that covers an upper portion of the rack, and a rib that is erected on a periphery of the top plate, extends downward, and is disposed on the outer side of the first side cover;
the rib is not formed in a portion overlapping with the second side cover, or is shorter in length than other portions and is formed so as not to cover an outer side of the second side cover . A battery module;
A rack that houses the battery module;
A cover for covering the rack;
A control unit accommodated in the rack;
A unit cover for covering the control unit;
Equipped with
The cover is provided with an exhaust valve portion that opens outwardly without coming off the cover to release pressure when the pressure inside the cover exceeds a predetermined threshold value,
The unit cover has an opening facing the exhaust valve portion.

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