Energy storage unit and energy storage system

Abstract

The present invention relates to an electricity storage unit and an electricity storage system that can efficiently recover low power. [Solution] In the energy storage system 1, there is provided an energy storage unit 30 configured to be connectable to at least one power generation device 10 that generates electricity using renewable energy and to a power transmission line 20, the energy storage unit having a diode 31 arranged on an electrical path EP from the power generation device to the power transmission line, and a power storage section 32 connected between the diode and the power transmission line, with the diode arranged so that the power generation device side is the anode and the power transmission line side is the cathode.

Description

[Technical Field]

[0001] The present invention relates to an electricity storage unit and an electricity storage system. [Background technology]

[0002] Conventionally, DC power generated by a solar power generation facility is converted into AC power by a PCS (Power Conditioning System) and supplied to a power grid (see Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-201453 Summary of the Invention [Problem to be solved by the invention]

[0004] However, general PCSs do not operate at low power (below 500W), but operate at high power (over 500W), and there is a problem that the amount of power generated by the solar power generation equipment is low during cloudy or rainy days, and the PCS does not operate, resulting in wasted power. On the other hand, if the performance of the PCS is improved, it will be possible to operate at low power, but this results in a problem of poor cost-effectiveness.

[0005] The present invention relates to an electricity storage unit and an electricity storage system that can efficiently recover low power. [Means for solving the problem]

[0006] The energy storage unit of the present invention is configured to be connectable to at least one power generation device that generates electricity using renewable energy and to a power transmission line, and the energy storage unit has a diode arranged on an electrical path from the power generation device to the power transmission line, and a power storage unit connected between the diode and the power transmission line, and the diode is arranged so that the power generation device side is the anode and the power transmission line side is the cathode.

[0007] In the energy storage unit according to the present invention, the diode may be a first diode, and the energy storage unit may have a second diode arranged downstream of the first diode and the energy storage unit on the electrical path, and the second diode may be arranged so that the power generation device side serves as an anode and the power transmission line side serves as a cathode.

[0008] In the power storage unit of the present invention, the power storage section may be at least one capacitor.

[0009] In the power storage unit of the present invention, the power storage section may be at least one secondary battery module.

[0010] In the energy storage unit of the present invention, the secondary battery module may have a plurality of secondary battery cells arranged in series, each secondary battery cell having a positive electrode and a negative electrode arranged opposite the positive electrode, the positive electrode and the negative electrode being made of a capacitive resin, and at least some of the secondary battery cells being arranged at intervals from each other and configured to function as a capacitor.

[0011] In the power storage unit of the present invention, the power storage unit may be a first power storage unit and may include a second power storage unit connected to the power transmission line.

[0012] The energy storage system of the present invention is an energy storage system including at least one power generation device that generates electricity using renewable energy, a power transmission line, and an energy storage unit configured to be connectable to the power generation device and the power transmission line, wherein the energy storage unit has a diode arranged on an electrical path from the power generation device to the power transmission line, and a storage unit connected between the diode and the power transmission line, and the diode is arranged so that the power generation device side is the anode and the power transmission line side is the cathode. [Effects of the Invention]

[0013] According to the power storage unit and the power storage system of the present invention, it is possible to efficiently recover low power. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating a power storage system according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram showing a secondary battery module according to an embodiment of the present invention; [Figure 3] FIG. 3(a) is a diagram showing an equivalent circuit in which a plurality of secondary battery cells are arranged in series, and FIG. 3(b) is a diagram showing a portion that functions as a capacitor. [Figure 4] 1 is a schematic diagram illustrating a secondary battery cell according to an embodiment of the present invention. [Figure 5] FIG. 2 is a schematic diagram showing a switch mechanism according to the present embodiment. [Figure 6] FIG. 2 is a diagram showing the flow of current during charging. [Figure 7] FIG. 2 is a diagram showing a current flow when power is supplied. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments for carrying out the present invention will be described below with reference to the drawings. Note that the following embodiments do not limit the inventions according to the claims, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. Furthermore, in the present embodiments, the scale and dimensions of each component may be exaggerated, and some components may be omitted.

[0016] [Overall configuration of the energy storage system] As shown in FIG. 1, the power storage system 1 includes at least one power generation device 10 that generates power using renewable energy, a power transmission line 20, and a power storage unit 30 that is connectable to the power generation device 10 and the power transmission line 20.

[0017] [Configuration of power generation equipment] The power generation device 10 is not particularly limited as long as it is a power generation device capable of generating electricity using renewable energy, and any power generation device can be used, for example, a solar power generation device, a wind power generator, a hydroelectric power generator, a biomass power generator, a geothermal power generator, etc. However, the effects of the present invention can be particularly enjoyed when a power generation device whose power generation amount is affected by the environment, such as a solar power generation device or a wind power generator, is used. In this embodiment, a solar power generation device is used as the power generation device 10. Note that, since a known power generation device can be used for the power generation device 10, detailed description thereof will be omitted.

[0018] [Power line configuration] The power transmission line 20 is configured to be able to transmit DC power generated by the power generation device 10 and supplied by the power storage unit 30, or DC power (AC / DC converted power) supplied from a power plant (not shown), to a predetermined substation. Note that a known power transmission line can be used for the power transmission line 20, and therefore a detailed description thereof will be omitted.

[0019] [Configuration of the energy storage unit] As shown in FIG. 1, the energy storage unit 30 includes a first diode 31 arranged on an electrical path EP extending from the power generation device 10 to the transmission line 20, a first energy storage unit 32 connected between the first diode 31 and the transmission line 20, a second diode 33 arranged downstream of the first diode 31 and the first energy storage unit 32 on the electrical path EP, and a second energy storage unit 34 connected to the transmission line 20.

[0020] The first diode 31 and the second diode 33 are arranged on the electrical path EP such that the power generation device 10 side serves as the anode and the power transmission line 20 side serves as the cathode. In other words, the first diode 31 is configured to allow current to flow from the power generation device 10 toward the power transmission line 20 and to block current to flow from the power transmission line 20 toward the power generation device 10. On the other hand, the second diode 33 is configured to allow current to flow from the power generation device 10 and the first power storage unit 32 toward the power transmission line 20 and to block current to flow from the power transmission line 20 toward the power generation device 10 and the first power storage unit 32.

[0021] From the viewpoint of preventing reverse current to the power generation device 10, it is preferable that the number of first diodes 31 provided be the same as the number of power generation devices 10. The number of second diodes 33 provided may be the same as the number of first diodes 31, or only one may be provided. The first diodes 31 and the second diodes 33 may be the same or different.

[0022] Known diodes can be used for the first diode 31 and the second diode 33, and detailed description thereof will be omitted.

[0023] The first power storage unit 32 and the second power storage unit 34 may each be at least one capacitor as shown in Fig. 1, or may each be at least one secondary battery module M as shown in Figs. 2 and 3. Furthermore, a mixture of capacitors and secondary battery modules M may also be used. Note that as known capacitors can be used as the capacitors, detailed description thereof will be omitted.

[0024] 2 and 3, the secondary battery module M preferably includes a plurality of secondary battery cells 100 arranged in series, and an exterior body 200 that houses the plurality of secondary battery cells 100. The exterior body 200 is not particularly limited, and a body that has conventionally been used in the field of secondary battery modules can be used, so a detailed description thereof will be omitted.

[0025] [Configuration of secondary battery cells] As shown in Figures 3 and 4, the secondary battery cell 100 includes a positive electrode 110, a negative electrode 120 arranged opposite the positive electrode 110, and a separator 130 arranged between the positive electrode 110 and the negative electrode 120, and is formed into a sheet shape having a laminated structure as a whole.

[0026] The positive electrode 110 has a positive electrode current collector 110a and a positive electrode active material layer 110b disposed between the positive electrode current collector 110a and the separator .

[0027] The positive electrode current collector 110a is made of any of various conductive resins and has conductivity and capacitance. The planar shape of the positive electrode current collector 110a is not particularly limited, and any shape such as a square, rectangular, or circular shape can be adopted.

[0028] The positive electrode active material layer 110b contains a positive electrode active material. The positive electrode active material is not particularly limited as long as it is a material that can absorb and release alkali metal ions such as lithium ions and sodium ions, and alkaline earth metal ions such as magnesium ions, and various arbitrary materials can be used.

[0029] The positive electrode active material may be coated with any of various polymer compounds. When the positive electrode active material is not coated with a polymer compound, the positive electrode active material layer 110b may contain an electrolytic solution in which any of various electrolytes are dissolved in any of various solvents. The positive electrode active material layer 110b may contain any of various conductive additives. When the positive electrode active material is coated with a polymer compound, the conductive additive may coat the positive electrode active material together with the polymer compound. When the positive electrode active material is not coated with a polymer compound, the positive electrode active material layer 110b may contain any of various binders.

[0030] The negative electrode 120 has a negative electrode current collector 120a and a negative electrode active material layer 120b disposed between the negative electrode current collector 120a and the separator .

[0031] The negative electrode current collector 120a is made of any of various conductive resins and has conductivity and capacitance. The planar shape of the negative electrode current collector 120a is not particularly limited and may be any shape such as a square, rectangular, or circular shape, but is preferably the same shape as the positive electrode current collector 110a.

[0032] The negative electrode active material layer 120b contains any of various negative electrode active materials. The negative electrode active material may be coated with the polymer compound described above, similar to the positive electrode active material. The negative electrode active material layer 120b may contain the electrolyte, conductive additive, and binder described above, similar to the positive electrode active material layer 110b.

[0033] The separator 130 is formed in a sheet shape. The planar shape of the separator 130 is not particularly limited, and any shape such as a square, rectangular, or circular shape can be adopted. The separator 130 may have a single-layer structure or a multi-layer structure. The separator 130 is not particularly limited as long as it is capable of transferring charge carriers, and various arbitrary separators can be used.

[0034] The secondary battery cell 100 may include a frame (not shown) for sealing the positive electrode active material layer 110b and the negative electrode active material layer 120b. Specifically, the frame may be disposed between the peripheral edge of the positive electrode current collector 110a and the peripheral edge of the negative electrode current collector 120a, and the separator 130 may be disposed midway along the axial direction of the frame. This allows the positive electrode current collector 110a, the separator 130, and the frame to seal the positive electrode active material layer 110b, and the negative electrode current collector 120a, the separator 130, and the frame to seal the negative electrode active material layer 120b. Note that a frame may be provided for each of the positive electrode active material layer 110b and the negative electrode active material layer 120b.

[0035] The secondary battery cells 100 having the above configuration are arranged at intervals from one another as shown in FIGS. 2 and 3 and are configured to function as a capacitor C. Specifically, the secondary battery cells 100 are arranged at intervals from one another such that adjacent positive electrode current collectors 110a and negative electrode current collectors 120a are arranged at intervals from one another, except for the positive electrode current collector 110a of the uppermost secondary battery cell 100 and the negative electrode current collector 120a of the lowermost secondary battery cell 100. The adjacent positive electrode current collectors 110a and negative electrode current collectors 120a are each configured to function as a capacitor C. As a result, electric charge is accumulated in the positive electrode current collector 11a and the negative electrode current collector 12a functioning as the capacitor C, and thus charging beyond the rated charging capacity of the secondary battery module M is possible.

[0036] Examples of methods for arranging the secondary battery cells 100 at intervals from each other include a method of providing a frame member between the peripheral edge of adjacent positive electrode current collector 110a and the peripheral edge of adjacent negative electrode current collector 120a, and a method of interposing a switching element such as an organic transistor between adjacent positive electrode current collector 110a and negative electrode current collector 120a (a method of sandwiching a switching element between the positive electrode current collector 110a and the negative electrode current collector 120a).

[0037] In this embodiment, all of the secondary battery cells 100 are described as being arranged at intervals from each other, but this is not limited to this, and it is sufficient that at least some of the secondary battery cells 100 are arranged at intervals from each other.

[0038] [Switch mechanism configuration] The secondary battery module M also includes a switch mechanism 300 capable of switching between charging and discharging by the capacitor C. The switch mechanism 300 may be a relay mechanism capable of switching between energization and de-energization between the secondary battery cells 100, a switching element, or the like. From the viewpoint of increasing the charge capacity of the secondary battery module M, it is preferable to use an element having a capacitance component (capacitor component) as the switching element, and for example, an organic transistor may be used. When a switching element is used as the switch mechanism 300, it may be disposed between the adjacent positive electrode current collector 110a and negative electrode current collector 120a, as shown in FIG. 5.

[0039] The secondary battery module M is configured to perform a discharging operation by the capacitor C by turning on the switch mechanism 300, and to perform a charging operation by the capacitor C by turning off the switch mechanism 300. In addition, the secondary battery module M is configured to perform a charging operation and a discharging operation by the secondary battery module M by turning on the switch mechanism 300.

[0040] [Charge and discharge operation of secondary battery module] When charging the secondary battery module M, the switch mechanism 300 is turned ON. In this state, when electricity flows through the secondary battery module M, electrons move from the positive electrode active material layer 110b of the positive electrode 110 and reach the negative electrode active material layer 120b of the negative electrode 120. In addition, positively charged alkali metal ions and alkaline earth metal ions reach the negative electrode active material layer 120b of the negative electrode 120 from the positive electrode active material layer 110b of the positive electrode 110. When all of the alkali metal ions and alkaline earth metal ions present in the positive electrode active material layer 110b reach the negative electrode active material layer 120b, charging to the rated charge capacity is completed.

[0041] Furthermore, when the switch mechanism 300 is turned OFF, electric charges are accumulated in the positive electrode current collector 110a and the negative electrode current collector 120a, which function as capacitors C. This allows charging beyond the rated charging capacity of the secondary battery module M.

[0042] When discharging the secondary battery module M, the switch mechanism 300 is turned ON. This causes the alkali metal ions and alkaline earth metal ions occluded in the negative electrode active material layer 120b of the negative electrode 120 to move from the negative electrode active material layer 120b toward the positive electrode active material layer 110b of the positive electrode 110. Also, electrons move from the negative electrode active material layer 120b of the negative electrode 120, pass through the load, and reach the positive electrode active material layer 110b of the positive electrode 110. This causes energy to be consumed (electricity to be used) in the load.

[0043] Furthermore, the charges stored in the positive electrode current collector 110a and the negative electrode current collector 120a, which function as capacitors C, are released, and energy is consumed (electricity is used) in the load.

[0044] [Electricity storage method and power supply method] Next, a method for storing electricity and a method for supplying electricity using the electricity storage system 1 will be described with reference to Fig. 6 and Fig. 7. In Fig. 6 and Fig. 7, the flow of current is indicated by arrows.

[0045] [Electricity storage method] When the electricity generated by the power generation device 10 is at a lower voltage than the electricity flowing through the power transmission line 20, as shown in FIG. 6, the electricity does not flow from the power generation device 10 to the power transmission line 20, but flows to the first power storage unit 32 and is stored in the first power storage unit 32.

[0046] [Power supply method] When the electricity generated by the power generation device 10 has a higher voltage than the electricity flowing through the power transmission line 20, the electricity flows from the power generation device 10 to the power transmission line 20 as shown in Fig. 7. Similarly, when the electricity stored in the first power storage unit 32 has a higher voltage than the electricity flowing through the power transmission line 20, the electricity flows from the first power storage unit 32 to the power transmission line 20 as shown in Fig. 7.

[0047] When surplus power is generated in the power transmission line 20, the surplus electricity flowing through the power transmission line 20 flows to the second power storage unit 34 and is stored in the second power storage unit 34, as shown in FIG.

[0048] [Advantages of the power storage system according to this embodiment] The energy storage unit 30 according to this embodiment is configured to be connectable to at least one power generation device 10 that generates electricity using renewable energy and to a power transmission line 20. The energy storage unit 30 has a diode 31 arranged on an electrical path EP from the power generation device 10 to the power transmission line 20, and an energy storage section 32 connected between the diode 31 and the power transmission line 20. The diode 31 is arranged so that the power generation device 10 side is the anode and the power transmission line 20 side is the cathode.

[0049] With the energy storage unit 30 having such a configuration, when the amount of power generated by the power generation device 10 is low, power is stored in the energy storage section 32, and when the amount of power generated by the power generation device 10 is high, the power stored in the energy storage section 32 can be supplied to the power transmission line 20 in addition to the power generated by the power generation device 10. In this way, the energy storage unit 30 according to this embodiment has the advantage of being able to efficiently recover low power. Furthermore, in the energy storage unit 30 according to this embodiment, the diode 31 is arranged so that the anode is on the power generation device 10 side and the cathode is on the power transmission line 20 side, which has the advantage of being able to prevent backflow to the power generation device 10.

[0050] In the energy storage unit 30 according to this embodiment, the diode 31 is a first diode 31, and the energy storage unit 30 has a second diode 33 arranged downstream of the first diode 31 and the energy storage unit 32 on the electrical path EP, with the second diode 33 arranged such that the power generation device 10 side serves as the anode and the power transmission line 20 side serves as the cathode. The energy storage unit 30 having such a configuration has the advantage that backflow to the energy storage unit 32 can be prevented, since the second diode 33 is arranged such that the power generation device 10 side serves as the anode and the power transmission line 20 side serves as the cathode.

[0051] In the power storage unit 30 according to this embodiment, the power storage section 32 is at least one capacitor or at least one secondary battery module M. The power storage unit 30 having such a configuration has the advantage of being easy to install as equipment.

[0052] In the energy storage unit 30 according to this embodiment, the secondary battery module M has a plurality of secondary battery cells 100 arranged in series, and each secondary battery cell 100 has a positive electrode 110 and a negative electrode 120 arranged opposite the positive electrode 110, the positive electrode 110 and the negative electrode 120 being made of a capacitive resin, and at least some of the secondary battery cells 100 are arranged at intervals from each other and are configured to function as capacitors C. The energy storage unit 30 having such a configuration has the advantage that the secondary battery cells 100 function as capacitors C, allowing charging beyond the rated charging capacity of the secondary battery module M.

[0053] In the power storage unit 30 according to this embodiment, the power storage unit 32 is a first power storage unit 32, and includes a second power storage unit 34 connected to the power transmission line 20. The power storage unit 30 having such a configuration has the advantage that surplus power on the power transmission line 20 can be stored in the second power storage unit 34.

[0054] [Variations] The power storage unit and the power storage system according to the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the technical concept of the present invention.

[0055] In the above-described embodiment, the power storage unit 30 has been described as including the second diode 33, but is not limited to this, and may be configured without the second diode 33.

[0056] In the above-described embodiment, the first power storage unit 32 and the second power storage unit 34 are described as being a capacitor, a secondary battery module M, or both, respectively, but are not limited to this and may be other known power storage devices.

[0057] In the above-described embodiment, the positive electrode 110 and the negative electrode 120 are described as being made of conductive resin, but are not limited to this and may be made of metal material or other resin material.

[0058] It is clear from the claims that the above-mentioned modifications are included within the scope of the present invention. [Explanation of symbols]

[0059] 1: Energy storage system 10: Power generation equipment 20: Power lines 30: Energy storage unit 31: First diode 32: First power storage unit 33: Second diode 34: Second storage unit 100: Secondary battery cell 110: Positive electrode 110a: Positive electrode current collector 110b: Positive electrode active material layer 120: Negative electrode 120a: Negative electrode current collector 120b: Negative electrode active material layer 130: Separator 200: Exterior body 300: Switch mechanism C: Capacitor EP: Electrical path M: Secondary battery module

Claims

1. A power storage unit configured to be connectable to at least one power generation device that generates power using renewable energy and to a power transmission line, The power storage unit is a diode disposed on an electrical path from the power generation device to the power transmission line; a power storage unit connected between the diode and the power transmission line; and The diode is arranged so that the power generation device side serves as an anode and the power transmission line side serves as a cathode, The power storage unit is at least one capacitor and is configured to store the electricity generated by the power generation device when the electricity generated by the power generation device has a lower voltage than the electricity flowing through the power transmission line. Energy storage unit.

2. A power storage unit configured to be connectable to at least one power generation device that generates power using renewable energy and to a power transmission line, The power storage unit is a diode disposed on an electrical path from the power generation device to the power transmission line; a power storage unit connected between the diode and the power transmission line; and The diode is arranged so that the power generation device side serves as an anode and the power transmission line side serves as a cathode, the power storage unit is at least one secondary battery module, the secondary battery module has a plurality of secondary battery cells arranged in series, The secondary battery cell has a positive electrode and a negative electrode disposed opposite the positive electrode, the positive electrode and the negative electrode have capacitive properties, At least some of the secondary battery cells are spaced apart from one another and configured to function as capacitors. Energy storage unit.

3. the diode is a first diode, the power storage unit includes a second diode disposed downstream of the first diode and the power storage unit on the electrical path; The second diode is arranged so that the power generation device side serves as the anode and the power transmission line side serves as the cathode. The power storage unit according to claim 1 or 2.

4. the power storage unit is a first power storage unit, a second power storage unit connected to the power transmission line; The power storage unit according to claim 1 or 2.

5. A power storage system including at least one power generation device that generates power using renewable energy, a power transmission line, and a power storage unit that is connectable to the power generation device and the power transmission line, The power storage unit is a diode disposed on an electrical path from the power generation device to the power transmission line; a power storage unit connected between the diode and the power transmission line; and The diode is arranged so that the power generation device side serves as an anode and the power transmission line side serves as a cathode, The power storage unit is at least one capacitor and is configured to store the electricity generated by the power generation device when the electricity generated by the power generation device has a lower voltage than the electricity flowing through the power transmission line. Energy storage system.

6. A power storage system comprising at least one power generation device that generates power using renewable energy, a power transmission line, and a power storage unit that is connectable to the power generation device and the power transmission line, The power storage unit is a diode disposed on an electrical path from the power generation device to the power transmission line; a power storage unit connected between the diode and the power transmission line; and The diode is arranged so that the power generation device side serves as an anode and the power transmission line side serves as a cathode, the power storage unit is at least one secondary battery module, the secondary battery module has a plurality of secondary battery cells arranged in series, The secondary battery cell has a positive electrode and a negative electrode disposed opposite the positive electrode, the positive electrode and the negative electrode have capacitive properties, At least some of the secondary battery cells are spaced apart from one another and configured to function as capacitors. Energy storage system.

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