WO2012136872A2

WO2012136872A2 - Distributed, hyrbird energy storage system

Info

Publication number: WO2012136872A2
Application number: PCT/ES2012/070233
Authority: WO
Inventors: Eugenio DOMÍNGUEZ AMARILLO; Antonio Jesús GUILLÉN LÓPEZ; Oliver MARTÍNEZ VITORIANO
Original assignee: Windinertia Technologies, S. L.
Priority date: 2011-04-04
Filing date: 2012-04-04
Publication date: 2012-10-11
Also published as: ES2405538B1; WO2012136872A3; ES2405538R1; ES2405538A2

Abstract

The invention relates to a distributed, hybrid energy storage system having high energy and power densities in order to allow the distribution of energy within the system, between different electric power micro-networks and with the electrical grid. According to the invention, the distributed, hybrid energy storage system allows consumption peaks to be managed adequately, power balances to be performed and the demand curve to be smoothed, as well as allowing voltage dips to be compensated, so that electric power can be managed in an efficient and reliable manner.

Description

HYBRID AND DISTRIBUTED ENERGY STORAGE SYSTEM- DESCRIPTION OBJECT OF THE INVENTION

The present invention aims at a hybrid and distributed energy storage system that has high energy and power densities to allow the distribution of energy within the system itself, between different micro-networks of electrical energy and with the electrical network itself, where The hybrid and distributed energy storage system allows the proper management of consumption peaks, power balances and a flattening of the demand curve, as well as the compensation of voltage dips, all for managing energy Electric efficiently and reliably.

BACKGROUND OF THE INVENTION

The integration of storage systems and / or power generation centers within the conventional electrical system leads to the formation of small electrical systems called electrical micro networks. These are governed by the same guidelines as conventional systems, and their greater or lesser integration depends on the global electrical system. A fundamental pillar in this energy management is the ability to store energy, allowing to decouple the power generation and consumption curves. On the other hand, in-situ power generation, distributed generation, favors obtaining a more efficient global electricity network (by not having to distribute energy over long distances) reliable and robust.

Currently, there are different energy storage technologies, which allow a relatively rapid conversion of stored energy into useful electricity. Among them are electrochemical batteries and supercapacitors.

An electrochemical battery is an electric accumulator element that stores electrical energy through electrochemical processes. It does not produce electricity itself, but releases what it has previously stored during charging. The main virtue of electrochemical batteries is the higher energy density (kwh / kg) they have compared to many other electrical storage devices. However, in order to safeguard their useful life, loading and unloading cycles must be performed at low speed, so that the power density is generally low. In addition, the yield is not very high and the heavy metals that form it are highly toxic.

Supercapacitors are electrical energy storage devices in the form of electrostatic charges, using pairs of conductive plates separated by a dielectric medium.

On a functional level, supercapacitors can be charged and unloaded in short periods of time, which gives a high power of loading and unloading, and makes them especially appropriate to respond to the needs of electricity consumption peaks or short-term supply interruptions. In addition, they allow a very high number of loading and unloading cycles without affecting their useful life. However, they have a low energy storage density.

The operation of the current electricity network is based on the balance of generation and consumption, as there is no energy storage capacity. This requires that the generation adapt to the demand curve, and during the hours of low consumption, it causes the disconnection of power generation centers, resulting in the loss of power generation capacity, especially of a renewable nature. The managing bodies of the electricity market act as a regulator of the energy generated based on an estimate of daily consumption, often resulting in the loss of generation points of a renewable nature due to its rapid dynamics and ease of disconnection causing considerable energy losses. On the other hand, any mismatch between generation and consumption, such as demand spikes or failures in the generation or electrical infrastructure, can cause damage to the power grid and the elements connected to it.

The hybrid and distributed energy storage system of the present invention is capable of storing the energy that is currently wasted providing greater stability and reliability against mismatches between the generation and consumption of the electricity grid. DESCRIPTION OF THE INVENTION

The present invention relates to a hybrid and distributed energy storage system that has a high capacity to solve the problem described above in the background section. This system, due to its own storage nature, allows energy management to be carried out, generating electricity generation and consumption to some extent, and that without its existence would not be possible. This leads to the promotion of flattening the demand curve, and greater integration of renewable energies within the local scope of a micro network.

When distributed, the system entails improvements in the integration and structural needs of the storage system. A scaled design allows the reduction of its volume, which also implies a reduction in its weight and cost, implying a greater penetration of technology and therefore greater storage capacities. This last one favors that the user of the technology approaches the project of energetic storage with a smaller investment.

The hybrid and distributed energy storage system comprises at least one hybrid storage subsystem that is controlled through a coordination and management subsystem or central operator, thereby obtaining a large-capacity global storage system, but without requiring large infrastructure for your shelter, expensive and on the other hand of great maintenance needs. On the other hand, the distribution of storage points allows a greater integration of renewable energy, since its installation can be carried out in a more localized way and with better adaptation to specific needs. All this makes the hybrid and distributed energy storage system, from the point of view of the electrical system, act as a primary consumer / generator. For its part, the hybrid storage subsystem comprises at least one supercapacitor and a battery that allow the system to have high energy and power densities. It is precisely the high power density that brings new features to the storage system of the present invention. On the one hand, it allows greater manageability of energy, allowing to provide or absorb large power peaks in very short periods of time (seconds or milliseconds). The technology responsible for this feature is supercapacitors, which prevent premature aging of the installation and storage technologies with lower power density, such as batteries. In addition, controlling the transfer and absorption of energy by supercapacitors can prevent batteries from performing unnecessary charge and discharge cycles. All this helps to extend their useful life.

This great capacity to absorb or yield high amounts of energy in short periods of time, allows to perform the damping or elimination of a phenomenon of great impact on electrical systems, power peaks, which in addition to deteriorating the system force have it oversized or with contracted powers greater than the nominal.

Addressing the problem of voltage gaps is another virtue of the system of the present invention. There has been talk of the flattening of the demand curve and the elimination of peaks, two of the operations of energy dispatching or distribution of energy. There is a third, power balance, which is also possible to carry out with the hybrid and distributed storage system of the present invention due to the ability to transfer or absorb reactive energy by the supercapacitors.

In this way, the hybrid and distributed storage system of the present invention can cope with large energy variations of rapid dynamics, thanks to supercapacitors, and provide energy continuously or for long periods of time thanks to the batteries.

The coordination and management subsystem between the different hybrid storage subsystems and / or among other distributed storage systems allows the sum of them to make a whole of greater energy storage capacity. Although the control is specific to each of the hybrid storage subsystems, the management of the entire system is the responsibility of the coordination and management subsystem. Under this idea, two new concepts arise in the coordination of the hybrid storage system and distributed by the coordination and management subsystem, which are, "Energy to share" or "energy to share" and "Energy to use" or "energy to use". The first refers to the amount of energy existing in the hybrid storage system and distributed to be able to be shared between the different hybrid storage subsystems that make up, or even with the electricity grid itself. The second refers to the energy that each of the hybrid storage subsystems possesses to ensure the supply of on-site consumption. Each hybrid storage subsystem comprises, in addition to at least one battery and a supercapacitor of those described above, one or more power converters, in addition to a communication subsystem with the coordination and management subsystem. The connection between these elements can be made through different configurations and technologies.

The batteries, preferably electrochemical, provide high energy storage capacity. However, they have a low load and discharge power, as well as a high response time. In addition, the realization of the loading and unloading cycles, and even more the failure to carry them out according to the manufacturer's instructions, shorten their useful life, so the number of cycles must be minimized and performed true to their characteristic curve. The responsibility for this to happen, partly lies with the presence of supercapacitors in the storage system and partly with control algorithms implemented in the power converters.

Supercapacitors provide low energy storage capacity, but with a high power density, which results in extremely low response times, of the order of seconds or milliseconds. In addition, due to their nature the loading and unloading cycles they support are very high, of the order of one million.

Therefore, the joint operation of electrochemical batteries and supercapacitors, in this invention, is complementary. The supercapacitors will allow to act before energetic changes of fast dynamics, and the batteries will be able to contribute energy during long periods of time.

The power converters transform the output current of the supercapacitors and electrochemical batteries (direct current), into injectable intensity to the power grid (alternating current). These power converters also transform in the reverse direction, absorbing energy from the power grid and transforming it to the appropriate voltage and current values for the recharge of batteries and supercapacitors. Additionally, power converters are communicated with the coordination and management subsystem.

The coordination and management subsystem, being connected to the power converters of all hybrid storage subsystems, receives information on the energy status of each hybrid storage subsystem and the generation and consumption centers of the power grid. This evaluates the general state of the hybrid and distributed energy storage system, the micro network generated with said system and the electricity network; and sends operating instructions to each power converter. It also monitors other characteristic parameters of the system and the power grid.

In summary, the invention relates to a hybrid and distributed energy storage system comprising

· At least one hybrid storage subsystem that includes:

or at least one battery and at least one supercapacitor to cope with fast dynamic energy variations while simultaneously providing energy,

or at least one power converter arranged between the battery and / or the supercapacitor and the mains, and

• a coordination and management subsystem to receive information on the energy status of each hybrid storage subsystem and the electrical network and manage the energy needs of the system, being connected to each power converter through a communication subsystem.

Among the possible applications of the hybrid and distributed energy storage system, on a non-limiting basis, are:

• Generation of electric micro-networks, with high manageability of electric energy, providing reliability and robustness to the electrical system.

· Creation of large-scale storage systems, based on the union of multiple distributed storage systems, which allow typical energy dispatching operations to be carried out.

• Generation of self-sufficient isolated micro networks.

• Integrative renewable energy systems. • Integration into the electrical infrastructure services derived from the needs created in the field of electromobility. Greater number of simultaneous recharges and greater number of fast recharging points.

• Voltage gap compensation system.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical implementation thereof, a set of drawings is attached as an integral part of said description. where, for illustrative and non-limiting purposes, the following has been represented:

An example of a hybrid and distributed energy storage system of the present invention comprising three hybrid storage subsystems is depicted in Figure 1.

PREFERRED EMBODIMENT OF THE INVENTION

In the preferred embodiment shown in Figure 1, the hybrid and distributed energy storage system comprises a set of hybrid storage subsystems, comprising an electrochemical battery (1), a set of supercapacitors (2), a first power converter ( 3) at the output of the electrochemical battery (1), a second power converter (4) at the output of the supercapacitor assembly (2), and a third power converter (5) that connects the output of the first and second converters of power (3, 4) with the power grid (6).

The hybrid and distributed energy storage system also comprises a coordination and management subsystem (7) and a communication subsystem (8) between each power converter (3, 4, 5) and the coordination and management subsystem (7).

Example 1

It is assumed a system of single-family homes, 15 units, where in each of them it is intended to carry out a photovoltaic installation, according to their needs. To favor the use of said energy, and provide greater electrical autonomy to each Housing is intended to install a distributed hybrid storage system (a storage system per home).

Each hybrid storage subsystem comprises one or more electrochemical batteries (1) of lithium-ion, a set of supercapacitors (2) and three power converters (3, 4, 5), with the following example configuration:

• Lithium-ion electrochemical batteries (1) that are connected to a first power converter (3), which raises the output voltage of the same to 400 Vdc.

• The supercapacitor assembly (2) is connected to a second power converter (4), which raises the output voltage of the same to 400 Vdc.

• The outputs of the first (3) and second (4) power converters mentioned in the previous two points are connected to a third power converter (5). This third power converter (5) transforms the input current to be injectable in the power grid (6) (220 Vac).

• The three power converters (3, 4, 5) mentioned can work both ways, that is, they are bidirectional, allowing two types of operations:

o Discharge of energy from electrochemical batteries (1) and supercapacitors (2) and current injection into the mains (6). o Extraction of power from the mains (6) and energy recharge of electrochemical batteries (1) and supercapacitors (2).

The power converters (3, 4, 5) communicate with a coordination and management subsystem (7), via PLC interface and protocol, or some kind of wireless communication. The coordination and management subsystem (7) consists of a calculation processing system, where appropriate control algorithms have been implemented for the overall coordination of the hybrid and distributed energy storage system. The coordination and management subsystem receives real-time information on the status and operation of each power converter (3, 4, 5) and the generation and consumption centers, evaluates the general state of the hybrid and distributed energy storage system of the microred or subsystem of hybrid storage and the electrical network (6), as well as the existing load in each house and sends operating instructions to each power converter (3, 4, 5). This example of the application of the distributed hybrid storage system gives the microred generated high versatility when carrying out the energy management of the system. When integrating an additional energy generating system of a renewable nature, it is important to keep in mind the hybrid adjective, because thanks to this the absorption of high generation peaks can be carried out for short periods of time. On the other hand, the fact that it is distributed, as in the previous section, allows the global energy storage potentially available to each home to be much greater than the capacity it has installed.

A clear example of this, can be given during a holiday period, where a number of considerable neighbors are absent from your home. In that case, their generation and energy systems could be used by neighbors who remain in their homes, increasing the autonomy characteristic of the network.

Example 2

The hybrid and distributed energy storage system is installed in the different charging points of electric vehicles, with extra power generation.

For example, several charging points can be located in a large car park whose roof houses an extended photovoltaic installation.

Specifically, for each charging point a hybrid storage subsystem is connected, comprising an electrochemical battery (1), a set of supercapacitors (2) and three power converters (3, 4, 5), with the following configuration:

• Electrochemical battery (1) lithium-ion that are connected to a first power converter (3), which raises the output voltage of the same to 400 Vdc.

• The outputs of the first (3) and second (4) power converters mentioned in the previous two points are connected to a third power converter (5). This third power converter (5) transforms the input current to be injectable in the mains (6) (220 Vac), or depending on whether the recharging service is performed in DC or AC, the corresponding converter will be connected of power (3, 4, 5). • The three power converters (3, 4, 5) mentioned can work both ways, that is, they are bidirectional, allowing two types of operations:

Each power converter (3, 4, 5) of each hybrid storage subsystem communicates with a coordination and management subsystem (7), via radio frequency connection and industrial communication protocol. The coordination and management subsystem (7) consists of a calculation processor system, where appropriate control algorithms have been implemented for the overall coordination of the distributed hybrid energy storage system. The coordination and management subsystem (7) receives real-time information on the status and operation of each power converter (3, 4, 5) and the generation and consumption centers, evaluates the general state of the hybrid energy storage system and distributed and the power grid (6) and sends operating instructions to each power converter (3, 4, 5).

This example of the application of the hybrid and distributed energy storage system allows fast recharging of electric vehicles without absorbing excessive power from the electricity network (6), allowing on the other hand to increase the number of simultaneous recharges, whether fast or standard. The coordination and management subsystem will allow the charging points to exchange energy with each other (each hybrid storage subsystem will have an amount of energy available for sharing and another amount of energy for use at the charging point in question), and even with the electrical network (6), allowing greater flexibility in the operation of the system. In this case, in addition, due to the large number of charge and discharge cycles that the storage system will suffer, the useful life of the batteries (1) can be increased to a greater extent with proper management of the charge and discharge of the supercapacitors ( 2) (whose useful life is estimated in millions of cycles). In other exemplary embodiments, the hybrid and distributed energy storage system may comprise several coordination and management subsystems (7) coordinated with each other, regardless of the organizational hierarchy establish between the different coordination and management subsystems (7), since in this case one of these coordination and management subsystems (7) would coordinate the rest.

Claims

R E I V I N D I C A C I O N E S

^/ \ - Hybrid and distributed energy storage system characterized by comprising

«At least one hybrid storage subsystem that includes:

or at least one battery (1) and at least one supercapacitor (2) to cope with energy dynamics of rapid dynamics as well as to provide energy continuously,

or at least one power converter (3, 4, 5) disposed between the battery (1) and / or the supercapacitor (2) and the power grid (6), and

• at least one coordination and management subsystem (7) to receive information on the energy status of each hybrid storage subsystem and the electrical network (6) and manage the energy needs of the system, being connected to each power converter (3, 4, 5) through a communication subsystem (8).

2. - Hybrid and distributed energy storage system according to claim 1 characterized in that each hybrid storage subsystem comprises a first power converter (3) at the output of the battery (1) and a second power converter (4) at the output of the supercapacitor (2).

3. - Hybrid and distributed energy storage system according to claim 2 characterized in that it comprises a third power converter (5) that connects the output of the first and second power converters (3, 4) with the power grid (6).

4. - Hybrid and distributed energy storage system according to any of the preceding claims characterized in that the power converters (3, 4, 5) are bidirectional to carry out both

or the discharge of energy from the batteries (1) and the supercapacitors (2) and the injection of current in the mains (6), such as

or the extraction of power from the mains (6) and the energy recharge of the batteries (1) and the supercapacitors (2).

5. - Hybrid and distributed energy storage system according to any of the preceding claims characterized in that it comprises several coordination and management subsystems (7) coordinated with each other.

6. Hybrid and distributed energy storage system according to any of the preceding claims characterized in that it also comprises a renewable energy integrator system.

7. Hybrid and distributed energy storage system according to any of the preceding claims characterized in that it also comprises any other energy storage system.