Patent Application
20200358127
The present invention relates to a power supply device in which a plurality of battery cells is stacked to form a battery stack, and a heat conduction plate is disposed in a thermally coupled state with the battery stack via end plates disposed at both ends of the battery stack, and a vehicle and power storage device including the power supply device.
A typical power supply device includes a battery stack including a plurality of prismatic battery cells, a pair of end plates disposed on both end surfaces of the battery stack, and a bind bar coupling the pair of end plates. In this power supply device, the battery stack including the plurality of prismatic battery cells can be assembled by restraining the battery stack with the end plates and the bind bar. Furthermore, a power supply device having a structure in which a cooling plate is disposed in a thermally coupled state on the surface of the battery stack to provide forcible cooling in order to efficiently cool the plurality of battery cells constituting the battery stack has been developed. (See PTL 1)
PTL 1: Unexamined Japanese Patent Publication No. 2015-220117
In a power supply device that cools battery cells with a cooling plate, for example, the cooling plate is fixed to a battery stack via a plurality of bolts. However, in the power supply device having this structure, the bolts that fix the cooling plate can be loosened with time. When the bolts are loosened, there is a possibility that the thermal coupling state between the cooling plate and the battery stack will deteriorate and the cooling efficiency of the battery cells will decrease. Further, loosening of the bolts causes noise due to vibration, and when they are removed, it causes various failures, which is not preferable, and it is earnestly desired to minimize it.
The present invention has been developed for the purpose of solving the above drawbacks, and an important object of the present invention is to provide a technique capable of preventing loosening of bolts over a long period of time and maintaining an ideal thermal coupling state between a cooling plate and a battery stack in a structure in which the cooling plate is fixed to the battery stack through the bolts.
A power supply device according to an aspect of the present invention includes a battery stack formed by stacking a plurality of battery cells, a pair of end plates disposed at both ends of the battery stack in a stacking direction, a bind bar having both ends coupled to the pair of end plates and restraining the plurality of battery cells in the stacking direction, and a cooling plate disposed on a surface of the battery stack in a thermally coupled state and made of metal different from metal of the bind bar, and fixes the cooling plate to the battery stack via a plurality of bolts disposed in a longitudinal direction of the battery stack. In the power supply device, length (L) of a fixed region formed by fixing the bind bar to the cooling plate with the plurality of bolts is set to less than or equal to 70% of total length (T) of the bind bar, and a non-fixed region that is not fixed to the cooling plate via the bolts is provided at an end of the bind bar.
Further, an electric vehicle including the power supply device including the configuration elements of the above aspect includes the power supply device, a motor for traveling supplied with electric power from the power supply device, a vehicle body equipped with the power supply device and the motor, and a wheel driven by the motor to cause the vehicle body to travel.
Further, a power storage device including the power supply device including the configuration elements of the above aspect includes the power supply device and a power supply controller that controls charging and discharging of the power supply device, in which the power supply controller enables charging of the battery cells with electric power from outside, and controls charging to be performed on the battery cells.
The present invention is capable of fixing a cooling plate to a battery stack in an ideal state via a plurality of bolts, furthermore preventing loosening of the bolts over a long period of time, and maintaining an ideal thermal coupling state between the cooling plate and the battery stack with a power supply device having a simple structure. This is because the above power supply device fixes a binding bar, which has both ends coupled to a pair of end plates that restrain the battery stack in the stacking direction, to the cooling plate with a plurality of bolts, and the cooling plate is disposed on the surface of the battery stack, and length (L) of the fixing region formed by fixing the bind bar to the cooling plate with the plurality of bolts is less than or equal to 70% of total length (T) of the bind bar, and at the end of the bind bar, a non-fixed region that is not fixed to the cooling plate via the bolts is provided.
First, one point of interest of the present invention will be described. A high-power power supply device mounted on a vehicle such as a hybrid vehicle or an electric vehicle has a large charging and discharging current and is used under various external conditions, and therefore the battery temperature fluctuates significantly. In particular, the temperature rise of the battery limits the range of current that can be charged and discharged, shortens the life, and impairs safety. Therefore, a power supply device with a structure that forcibly cools the battery with a cooling plate has been developed.
In the conventional power supply device, as shown in
The bolts can be disposed side by side in a longitudinal direction of the bent portion and can fix the elongated bent portion to the cooling plate. With this fixing structure, the cooling plate can be disposed on the bottom surface of the battery stack with the plurality of bolts in a preferable thermal coupling state. However, when the power supply device having this structure is used for a long period of time in a temperature environment that fluctuates significantly, the bind bar and the cooling plate relatively move, generating an adverse effect that the bolts loosen. When the bolts loosen, the thermal coupling state between the cooling plate and the battery stack deteriorates, and the cooling efficiency of each battery cell by the cooling plate is reduced, and furthermore the loosening of the bolts causes noise due to vibration and removal causes various failures. In particular, when the cooling plate and the bind bar are made of different metals, the relative movement between the bind bar and the cooling plate, which causes loosening of the bolts, occurs due to the difference in thermal expansion coefficient between the respective materials. For example, since the bind bar requires extremely strong tensile strength, high-tensile steel or stainless steel plate is used for the bind bar. On the other hand, since the cooling plate requires excellent heat conduction characteristics, aluminum or an aluminum alloy is used for the cooling plate. The bind bar and the cooling plate are required to have different characteristics, and a metal optimal for each application is selected, and they are made of different metals. Since the power supply device mounted on the electric vehicle is used in an extremely wide temperature range, the bind bar and the cooling plate expand and contract with respect to each other due to temperature changes. Since the amounts of expansion and contraction of the bind bar and the cooling plate made of different metals with respect to temperature are different from each other, the bind bar and the cooling plate are relatively displaced each time expansion and contraction due to temperature change occur, which causes loosening of the bolts. For this reason, the power supply device that fixes the cooling plate to the bind bar with the bolts can bring the cooling plate and the battery stack into an ideal thermally coupled state immediately after the manufacturing, but when it is used over a long period of time, loosening of the bolts generates various adverse effects such as deterioration of the thermal coupling state between the cooling plate and the battery stack.
Therefore, in the power supply device having the structure in which the cooling plate is thermally coupled to the battery stack to effect cooling, it is important to consider a structure that prevents loosening of the bolts for fixing the cooling plate to the battery stack for a long period of time, and can maintain the cooling plate and the battery stack in an ideal thermally coupled state.
The power supply device according to an aspect of the present invention may be specified by the following configuration. The power supply device includes battery stack 2 formed by stacking a plurality of battery cells 1, a pair of end plates 3 disposed at both ends of battery stack 2 in a stacking direction, bind bar 4 having both ends coupled to the pair of end plates 3 and restraining the plurality of battery cells 1 in the stacking direction, and cooling plate 9 disposed on a surface of battery stack 2 in a thermally coupled state and made of a metal different from that of bind bar 4, and fixes cooling plate 9 to battery stack 2 via a plurality of bolts 5 disposed in a longitudinal direction of battery stack 2. In the power supply device, a length (L) of fixed region 21 formed by fixing bind bar 4 to cooling plate 9 with the plurality of bolts 5 is set to less than or equal to 70% of a total length (T) of bind bar 4, and non-fixed region 22 that is not fixed to cooling plate 9 via bolts 5 is provided at an end of bind bar 4.
The above power supply device fixes the bind bar to the cooling plate via the plurality of bolts. However, by limiting the length (L) of the fixed region where the bolts are fixed to the cooling plate to be narrow, at a fixed part of the bolts, it is possible to reduce the relative amount of expansion and contraction between the bind bar and the cooling plate due to temperature changes.
By the way, when a number of bolts for fixing the bind bar to the cooling plate is reduced, for example, only the central portion of the bind bar and the cooling plate is fixed by one bolt, it is necessary to use a thick and strong bolt to achieve sufficient coupling strength. In the power supply device that fixes the bind bar to the cooling plate with the thick bolt, the bolt becomes bulky and has a large outer shape, and furthermore because the thick bolt is screwed or penetrated into the cooling plate, a refrigerant passage provided in the cooling plate becomes narrow so that it becomes impossible to uniformly cool the entire cooling plate.
On the other hand, in the above power supply device, since the bind bar is fixed to the cooling plate via the plurality of bolts disposed in the fixed region, sufficient coupling strength can be achieved even when the individual bolts are made thin. In this way, in the power supply device that fixes the bind bar to the cooling plate with the thin bolts, each bolt is prevented from becoming bulky and can have a small outer shape, and furthermore because the bolt is thin, a refrigerant passage provided in the cooling plate is prevented from becoming narrow so that it is possible to achieve a feature that can uniformly cool the entire cooling plate.
In the power supply device, it is preferable that bind bar 4 be iron or iron alloy and cooling plate 9 be aluminum or aluminum alloy. Further, it is preferable that cooling plate 9 have a total length (R) of 30 cm or more.
Further, the power supply device may be configured such that bind bar 4 has bent portion 4b fixed to the surface of cooling plate 9 and bind bar 4 is fixed to cooling plate 9 via bolts 5 penetrating bent portion 4b.
Furthermore, the power supply device may be configured such that bent portion 4b is disposed on an outer surface of cooling plate 9 and bent portion 4b is fixed to the outer surface of cooling plate 9.
Furthermore, the power supply device may be configured such that bent portion 4b is disposed between cooling plate 9 and battery stack 2 and bent portion 4b is fixed to a surface of cooling plate 9 facing battery stack 2.
Furthermore, in the power supply device, it is preferable that three or more bolts 5 be disposed in fixed region 21. Bolts 5 may be configured to be screwed and fixed in female screw holes 9a provided in cooling plate 9. Alternatively, it may be configured such that nut 6 is screwed into bolt 5 and cooling plate 9 is sandwiched between bolt 5 and nut 6 to fix bind bar 4 to cooling plate 9.
Furthermore, the power supply device may be configured such that cooling plate 9 has flange portions 9Y on both sides extending along a longitudinal direction and battery stack 2 is fitted on an inner side of flange portions 9Y.
Moreover, the power supply device may be configured such that heat conduction sheet 32 is disposed between battery stack 2 and cooling plate 9.
Hereinafter, an exemplary embodiment of the present invention will be described with reference to the drawings. However, an exemplary embodiment described below is an example for embodying the technical idea of the present invention, and the present invention is not limited to the following. Further, in the present specification, members indicated in the claims are not limited to the members of the exemplary embodiment. In particular, the dimensions, materials, shapes, and the relative arrangements of the constituent members described in the exemplary embodiment are not intended to limit the scope of the present invention thereto unless otherwise specified, and are merely illustrative examples. Nothing more. The sizes and positional relationships of members shown in the drawings may be exaggerated for clarity of description. Further, in the following description, the same names and reference numerals indicate the same or similar members, and detailed description will be appropriately omitted. Further, each element constituting the present invention may be configured such that a plurality of elements is configured by the same member and one member also serves as a plurality of elements, or conversely, the function of one member can be shared and achieved by a plurality of members. Also, the content described in some of examples and exemplary embodiments may be applicable to other examples and exemplary embodiments.
Power supply device 100 shown in
As shown in
In battery cell 1, an electrode body (not shown) is housed in metal battery case 10 having a prismatic outer shape and battery case 10 is filled with an electrolyte solution. Battery case 10 made of a metal case can be manufactured from aluminum or an aluminum alloy. Battery case 10 includes exterior can 10A formed by pressing a metal sheet into a cylindrical shape having a closed bottom and sealing plate 10B that hermetically closes an opening of exterior can 10A. Sealing plate 10B is a flat metal sheet and has an outer shape that is the same as the shape of the opening of exterior can 10A. Sealing plate 10B is laser-welded and fixed to an outer peripheral edge of exterior can 10A to hermetically close the opening of exterior can 10A. Sealing plate 10B fixed to exterior can 10A has positive and negative electrode terminals 13 fixed at both ends, and gas exhaust port 12 is provided in the middle of positive and negative electrode terminals 13. Inside gas exhaust port 12, exhaust valve 11 that opens at a predetermined internal pressure is provided. In battery stack 2 shown in
The plurality of battery cells 1 stacked on each other is connected in series and/or in parallel by connecting positive and negative electrode terminals 13. Power supply device 100 connects positive and negative electrode terminals 13 of adjacent battery cells 1 to each other in series and/or in parallel via a bus bar (not shown). The power supply device in which adjacent battery cells are connected in series to each other can increase the output voltage to increase the output, and can connect the adjacent battery cells in parallel to increase the charging and discharging current.
In battery stack 2 shown in
As shown in
As described above, in battery cell 1 which is stacked by being insulated by spacer 7, the exterior can be made of metal such as aluminum. However, in the battery stack, it is not necessarily required to interpose the spacer between the battery cells. This is because the spacer can be unnecessary when adjacent battery cells are insulated from each other by a method in which the exterior can of the battery cell is formed of an insulating material, or the outer circumference of the exterior can of the battery cell is covered with an insulating sheet, an insulating coating or the like, or the like. Further, in the battery stack without the spacer between the battery cells, the battery cells can be cooled by adopting a system that directly cools the battery cells using a cooling medium or the like without adopting an air-cooled system that cools the battery cells by forcibly flowing cooling air between the battery cells.
End plate 3 is coupled to bind bar 4, disposes battery stack 2 on both end surfaces, and holds battery cells 1 in the stacking direction. End plate 3 is fixed to bind bar 4 and fixes each battery cell 1 of battery stack 2. The outer shape of end plate 3 is almost equal to or slightly larger than the outer shape of battery cell 1, and it is a prismatic plate material with bind bars 4 fixed to the outer circumferential surfaces of both sides so as to have the strength that suppresses movement of the cells even when battery stack 2 is vibrated or impacted. End plate 3 is generally made of metal such as aluminum or aluminum alloy. However, although not shown, the end plate may have a structure in which a metal sheet is stacked on plastic, or may be a fiber-reinforced resin molded plate in which reinforcing fibers are embedded entirely.
End plate 3 is in close contact with the surface of battery cell 1 in a surface contact state directly or via a spacer to fix battery cell 1. In the assembly process, in power supply device 100, end plates 3 are disposed at both ends of battery stack 2, end plates 3 at both ends are pressed by a pressing machine (not shown), and bind bars 4 are inserted. After end plates 3 are fixed to bind bars 4, the pressurization state of the pressing machine is released.
Cooling plate 9 cools battery cells 1 with a cooling liquid circulating inside. In order to efficiently conduct the heat energy of battery cells 1 to the cooling liquid, cooling plate 9 is made of a metal sheet such as aluminum or aluminum alloy having excellent heat conduction characteristics. Cooling plate 9 includes circulation path 31 for the cooling liquid provided therein. Circulation path 31 is coupled to cooling mechanism 30 to cool cooling plate 9. In power supply device 100 of
Cooling plate 9 is fixed in a close contact state to the surface of battery stack 2 via bind bar 4. In power supply device 100 of
Cooling plate 9 is fixed to bind bar 4 and fixed to battery stack 2 in a thermally coupled state. Bind bar 4 shown in the schematic cross-sectional views of
In power supply device 100 of
In power supply device 200 of
Both ends of bind bar 4 are fixed to end plates 3 to restrain battery cells 1 of battery stack 2 in the stacking direction. At the time of vibration and impact, bind bar 4 is subject to strong tensile force by the load from battery stack 2. Bind bar 4 is made of high-tensile steel or stainless steel plate so as to withstand the load of battery stack 2. Cooling plate 9 requires excellent heat conduction characteristics, and bind bar 4 requires characteristics for withstanding the strong tensile force. Therefore, cooling plate 9 and bind bar 4 are made of different metals. Cooling plate 9 and bind bar 4 made of different metals have different amounts of expansion and contraction with respect to temperature changes. For example, the thermal expansion coefficient of aluminum is about twice that of steel. Therefore, the amount of expansion and contraction with respect to temperature changes of cooling plate 9 made of aluminum is twice that of bind bar 4 made of high-tensile steel. When different metals having different amounts of expansion and contraction with respect to temperature are coupled, a relative displacement occurs between the different metals due to temperature changes. The displacement between the different metals due to temperature changes occurs at the coupling portion between bind bar 4 and cooling plate 9. In the structure in which bind bar 4 and cooling plate 9 made of different metals are fixed by bolts 5, bind bar 4 and cooling plate 9 relatively move due to temperature changes, which causes bolts 5 to loosen. In particular, since the power supply device is used in an extremely wide pressing range, the relative movement with respect to temperature changes is large, which causes bolts 5 to loosen.
In order to fix bind bar 4 to cooling plate 9 with the plurality of bolts 5 and prevent bolts 5 from loosening, length (L) of fixed region 21 where bolts 5 fix bind bar 4 to cooling plate 9 is less than or equal to 70% of total length (T) of bind bar 4, and non-fixed regions 22 where bolts 5 do not fix bind bar 4 are provided at an end of bind bar 4. In power supply devices 100, 200 of
Fixed region 21 with respect to total length (T) of bind bar 4 can be reduced in length (L) to reduce loosening of bolts 5 due to temperature changes. Further, fixed region 21 can be made long so that bind bar 4 can be fixed to cooling plate 9 more securely. Further, the loosening of bolts 5 due to temperature changes also changes depending on total length (R) of cooling plate 9, that is, total length (T) of bind bar 4. Therefore, length (L) of fixed region 21 with respect to total length (T) of bind bar 4 is set to an optimum value in consideration of total length (T) of bind bar 4. In power supply devices 100, 200, length (L) of fixed region 21 is set to less than or equal to 70% of total length (T) of bind bar 4 or total length (R) of cooling plate 9. However, in the power supply device in which the total length of cooling plate 9 or bind bar 4 is 30 cm or more, length (L) of fixed region 21 with respect to total length (T) of bind bar 4 is limited to, for example, less than or equal to 60%, preferably less than or equal to 50%, more preferably less than or equal to 40% in consideration of the loosening of bolts 5 due to temperature changes and the strength for fixing bind bar 4 to cooling plate 9.
In power supply devices 100, 200 of
In power supply devices 300, 400 shown in the schematic cross-sectional views of
Cooling plate 9 described above can integrally include flange portions 9Y by die-casting or extrusion-molding aluminum. However, flange portions 9Y can be provided as separate members by fixing flange portions 9Y to main body 9X. Although the power supply devices of the above-described exemplary embodiment are configured to include cooling plate 9 that cools battery cells 1 with the cooling liquid that circulates inside, in the present invention, the cooling plate is not necessarily configured to circulate the cooling liquid inside the plate. Specifically, the cooling plate may be a heat conduction plate formed by molding a material having a high heat transfer property such as aluminum. In the case of this configuration, the battery cells can be cooled by utilizing the heat transfer property of the plate, and since it is not necessary to circulate a cooling liquid or the like, the configuration can be simplified. These may be selected according to the required cooling performance.
Power supply devices 100, 300 of
(1) A predetermined number of battery cells 1 are stacked in the thickness direction of battery cells 1 with spacers 7 interposed therebetween to form battery stack 2.
(2) End plates 3 are disposed at both ends of battery stack 2, and a pair of end plates 3 are pressed and held from both sides by a pressing machine (not shown). Further, cooling plate 9 is disposed on the bottom surface of battery stack 2 with heat conduction sheet 32 interposed therebetween. In power supply device 300 of
(3) While pressing battery stack 2 with end plates 3, bind bar 4 is coupled and fixed to the pair of end plates 3, and bind bar 4 is fixed to cooling plate 9. Bind bar 4 has fixing piece 4a provided at both ends fixed to the outer surface of end plate 3 via fixing screws 8. Further, bind bar 4 is fixed to the outer surface of cooling plate 9 by screwing bolts 5 penetrating bent portion 4b provided at the lower end into female screw holes 9a of cooling plate 9.
In this state, battery stack 2 is held by the pair of end plates 3 held at predetermined intervals by bind bar 4, and fixed to cooling plate 9 via bolts 5.
(4) On both sides of battery stack 2, opposing electrode terminals 13 of battery cells 1 adjacent to each other are coupled by a bus bar (not shown). The bus bar is fixed to electrode terminals 13 and connects battery cells 1 in series, or in series and in parallel. The bus bar is fixed to electrode terminals 13 by welding or screwing to electrode terminals 13.
Further, power supply devices 200, 400 of
(1) A predetermined number of battery cells 1 are stacked in the thickness direction of battery cells 1 with spacers 7 interposed therebetween to form battery stack 2.
(2) End plates 3 are disposed at both ends of battery stack 2, the pair of end plates 3 are pressed from both sides by a pressing machine (not shown) to press battery stack 2 with a predetermined pressure with end plates 3 so as to hold battery cells 1 in a compressed state.
(3) Battery stack 2 is fixed by coupling bind bar 4 to the pair of end plates 3 in a compressed state by end plates 3. Bind bar 4 has fixing piece 4a provided at both ends fixed to the outer surface of end plate 3 via fixing screws 8.
In this state, battery stack 2 is held via the pair of end plates 3 held at predetermined intervals by bind bar 4.
(4) Bent portion 4b of bind bar 4 is fixed to cooling plate 9. Bent portion 4b is disposed between cooling plate 9 and battery stack 2, and is fixed to the surface of cooling plate 9 facing battery stack 2. In bind bar 4, bolts 5 penetrating bent portion 4b are inserted into through-holes 9b of cooling plate 9, and nuts 6 are screwed onto bolts 5, so that cooling plate 9 is sandwiched and fixed between bolts 5 and nuts 6. At this time, heat conduction sheet 32 is interposed between battery stack 2 and cooling plate 9. In power supply device 400 of
(5) On both sides of battery stack 2, opposing electrode terminals 13 of battery cells 1 adjacent to each other are coupled by a bus bar (not shown). The bus bar is fixed to electrode terminals 13 and connects battery cells 1 in series, or in series and in parallel. The bus bar is fixed to electrode terminals 13 by welding or screwing to electrode terminals 13.
The power supply devices described above are optimum for a power supply device for a vehicle that supplies power to a motor that drives an electric vehicle. As an electric vehicle equipped with the power supply device, an electric vehicle such as a hybrid vehicle or a plug-in hybrid vehicle that runs on both an engine and a motor, or an electric vehicle that runs only on a motor can be used, and the power supply device is used as a power source for these electric vehicles.
Further,
Furthermore, the present invention does not limit the application of the power supply device to a power supply device mounted on an electric vehicle, and can be used as a power supply device for a power storage apparatus that stores natural energy such as solar power generation and wind power generation, and can be used for all applications that store large electric power, such as a power supply device for a power storage device that stores electric power at midnight. The present invention can also be used, for example, as a power source for households and factories, for a power supply system that is charged with sunlight, midnight power, or the like, and discharges when necessary, a power source for street lights that charges sunlight during the day and discharges at night, or a backup power source for driving traffic signals that is driven at the time of power failure. Such an example is shown in
In power storage device 80 shown in
Therefore, power storage device 80 has a charge mode and a discharge mode. Load LD and charging power source CP are connected to power storage device 80 via discharge switch DS and charge switch CS, respectively. ON/OFF of discharge switch DS and charge switch CS is switched by power supply controller 84 of power storage device 80. In the charge mode, power supply controller 84 turns on charge switch CS and turns off discharge switch DS to permit charging from charging power source CP to power storage device 80. In addition, when charging is completed and the battery is fully charged, or when the capacity of a predetermined value or more is charged and in response to a request from load LD, power supply controller 84 turns off charge switch CS and turns on discharge switch DS to switch the mode to the charge mode to permit discharging from power storage device 80 to load LD. If necessary, charge switch CS may be turned on and discharge switch DS may be turned on to supply load LD with power and charge power storage device 80 simultaneously.
Load LD driven by power storage apparatus 80 is connected to power storage device 80 via discharge switch DS. In the discharge mode of the power storage apparatus 80, power supply controller 84 turns on discharge switch DS to connect to load LD and drives load LD with the power from power storage device 80. As discharge switch DS, a switching element such as a field effect transistor (FET) can be used. ON/OFF of discharge switch DS is controlled by power supply controller 84 of power storage device 80. Further, power supply controller 84 includes a communication interface for communicating with external devices.
In the example of
Each power supply device 100 includes a signal terminal and a power source terminal. The signal terminal includes input and output terminal DI, abnormality output terminal DA, and connection terminal DO. Input and output terminal DI is a terminal for inputting and outputting a signal from other power supply device 100 or power supply controller 84, and connection terminal DO is a terminal for inputting and outputting a signal to and from other power supply device 100. Further, abnormality output terminal DA is a terminal for outputting the abnormality of power supply device 100 to the outside. Further, the power source terminal is a terminal for connecting power supply devices 100 to each other in series and in parallel. Further, power source units 82 are connected to output line OL via parallel connection switch 85 and are connected in parallel with each other.
The power supply device according to the present invention, and an electric vehicle and a power storage device including the same can be suitably used as a power supply device for a plug-in hybrid electric vehicle and a hybrid electric vehicle that can switch between EV driving mode and HEV driving mode, an electric vehicle, or the like. A backup power source that can be appropriately used for applications including a backup power supply device that can be mounted on a computer server rack, a backup power supply device for wireless base stations of, for example, cellular phones, a power storage device combined with a solar battery, such as a power storage power source for homes and factories or a power source for street lights, and a backup power source for traffic lights.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-010948 | Jan 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/043384 | 11/26/2018 | WO | 00 |
