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DE-102024132651-A1 - Stationary energy storage system

DE102024132651A1DE 102024132651 A1DE102024132651 A1DE 102024132651A1DE-102024132651-A1

Abstract

A stationary energy storage system (1) is described. This energy storage system (1) comprises a battery rack (2) with a plurality of cells and a load terminal (10) to which a load (16) is connected, at least in the intended operating state. Furthermore, the energy storage system (1) comprises an AC/DC converter (14) connected between a grid connection (12) and the load terminal (10) for providing operating energy at the load terminal (10), and a DC/DC converter (6) connected between the battery rack (2) and the load terminal (10) for providing operating energy at the load terminal (10). The energy storage system (1) also comprises switching means (8) by means of which the AC/DC converter (14) and the DC/DC converter (6) can be reversibly connected to the load terminal (10). The switching means (8) are designed to automatically connect the DC/DC converter (6) to the load connection (10) in a power-free state on one AC/DC converter side, independently of any power supply via the AC/DC converter side.

Inventors

  • Sanghoon Kim

Assignees

  • POWERCO SE

Dates

Publication Date
20260513
Application Date
20241108

Claims (10)

  1. Stationary energy storage system (1) comprising: - a battery rack (2) with a plurality of cells, - a load terminal (10) to which a load (16) is connected at least in the intended operating state, - an AC/DC converter (14) connected between a mains connection (12) and the load terminal (10) for providing operating energy at the load terminal (10), - a DC/DC converter (6) connected between the battery rack (2) and the load terminal (10) for providing operating energy at the load terminal (10), - switching means (8) by means of which the AC/DC converter (14) and the DC/DC converter (6) can be reversibly connected to the load terminal (10), wherein the switching means (8) are configured to automatically connect the DC/DC converter (6) to the load terminal (10) independently of an energy supply via the AC/DC converter side when there is no energy supply on one side of the AC/DC converter. connect.
  2. Stationary energy storage system (1) according to Claim 1 , wherein the AC/DC converter (14) is configured to provide operating energy at a higher operating voltage value than the DC/DC converter (6).
  3. Stationary energy storage system (1) according to Claim 2 , wherein the switching means (8) comprise passive components (20, 24) which are designed such that, based on the larger operating voltage value when the operating energy is provided by the AC/DC converter (14), the injection of operating energy by the DC/DC converter (6) to the load terminal (10) is blocked or at least reduced.
  4. Stationary energy storage system (1) according to Claim 3 , wherein the passive components are formed by at least two, in particular identical, diodes (20, 24) which are each connected between the AC/DC converter (14) and a connection point (22) to the load connection (10) or between the DC/DC converter (6) and the connection point (22).
  5. Stationary energy storage system (1) according to Claim 1 , wherein the switching means (8) comprise a single pole dual throw relay (30) having a first input (32) and a second input (34), an output (36) and an actuator (38), wherein in a normal state the first input (32) is always connected to the output (36), wherein the actuator (38) is configured to connect the output (36) to the second input (14) in an active state when the operating energy is supplied by the AC/DC converter (14), wherein the load terminal (10) is connected to the output (36), the DC/DC converter (6) to the first input (32) and the AC/DC converter (14) to the second input (34).
  6. Stationary energy storage system (1) according to Claim 5 , wherein the actuator (38) is connected to the AC/DC converter side for power supply.
  7. Stationary energy storage system (1) according to Claim 1 , wherein the circuit means (8) comprise a diode (50) connected between the AC/DC converter (14) and the load terminal (10) and a transistor, in particular a field-effect transistor, preferably an N-channel FET (52), connected between the DC/DC converter (6) and the load terminal (10).
  8. Stationary energy storage system (1) according to Claim 7 , wherein a gate driver (54) is connected for the gate connection of the transistor (52) on a DC/DC converter side of the transistor (52).
  9. Stationary energy storage system (1) according to Claim 7 or 8 , wherein a monitoring circuit (56) for the operating energy provided by the AC/DC converter (14) is arranged on a DC/DC converter side of the transistor (52), wherein the monitoring circuit (56) is configured to cause the transistor (52) to be switched on for the operating energy provided by the DC/DC converter (6).
  10. Stationary energy storage system (1) according to one of the Claims 5 until 9 , wherein at least one capacitor (40) is connected between the circuit means (8) and the load connection (10) for the short-term power supply during a switching operation of the circuit means (8).

Description

The invention relates to a stationary energy storage system, which in particular comprises a battery rack. Stationary energy storage systems, also known as ESS (energy storage systems), are known for storing energy. However, they differ from conventional battery systems, such as those used in private households for storing energy generated by photovoltaics. ESS systems typically include associated operating units such as air conditioning systems, particularly cooling systems (e.g., HVAC) for extremely low operating temperatures in the range of -10 to -40 degrees Celsius, especially -20 to -30 degrees Celsius, battery management systems, and sometimes also fire extinguishing and/or fire suppression systems. Under normal operating conditions, these operating units are usually powered by energy supplied via a grid connection, i.e., from an external power grid (utility network). This allows for energy savings within the ESS system. "Stationary" here does not mean completely immobile. Systems are also known that are housed in a container-like enclosure and can therefore be set up and used, for example, at construction sites. "Stationary" in this context means that a connection to the power grid is required, and the ESS (Energy Supply System) cannot be used completely arbitrarily or even in a mobile manner. However, such energy storage systems (ESS) are also interesting if they can continue operating in the event of a power outage. For this purpose, ESSs conventionally include an auxiliary or emergency power supply (UPS for "uninterruptible power supply"). This typically comprises a number of battery cells to bridge a short power outage. The longer the required bridging period, the more expensive such UPS systems become. Disadvantages of a UPS include the usually limited lifespan of the internal battery cells (especially since they must always be kept at a near-full charge level), as well as the required installation space and weight. The invention is based on the objective of improving a stationary energy storage system. This problem is solved according to the invention by a stationary energy storage system with the features of claim 1. Advantageous and partly inventive embodiments and further developments of the invention are set out in the dependent claims and the following description. The stationary energy storage system (ESS) comprises a battery rack, which in turn contains a plurality of (preferably secondary) cells (in particular, a large number of these subdivided into separate battery modules). Furthermore, the ESS has a load terminal to which, at least in its intended operating state, a load (consumer) is connected. The ESS also includes an AC/DC converter (rectifier) connected between a grid connection and the load terminal to provide operating power at the load terminal, and a DC/DC converter (voltage-direction converter) connected between the battery rack and the load terminal to provide operating power at the load terminal. Finally, the ESS includes switching means by which the AC/DC converter and the DC/DC converter (in particular, each) can be reversibly connected to the load terminal. These switching devices are designed to automatically connect the DC/DC converter to the load connection via the AC/DC converter side, independently of any energy supply, when there is no energy supplied to the AC/DC converter side (i.e., in particular at the mains connection or at least on the output side to the AC/DC converter). Preferably, the ESS does not include an uninterruptible power supply (UPS) module for the additional power supply of auxiliary modules that are connected to the load terminal as consumers, at least during the intended operation of the ESS. Such auxiliary modules include, for example, HVAC (heating, ventilation and air conditioning), a battery management system (BMS), a fire suppression system, and/or the like. The use of the switching devices described above advantageously enables automatic switching from external power supply (provision of operating energy) to "internal" power supply, even in cases where the external power supply unexpectedly fails, for example, in the event of a power outage in the grid to which the ESS is connected via its mains connection. This allows for near-autonomous operation, particularly of the ESS's additional modules, which are otherwise operated with externally supplied power in conventional ESS systems. For example, cooling can be maintained via the HVAC system or a separate cooling unit. In a suitable design, the AC/DC converter is configured to provide operating energy at a higher operating voltage than the DC/DC converter under normal operating conditions. For example, the "mains-side" operating voltage provided by the AC/DC converter is 27 V, while the "battery-side" operating voltage provided by the DC/DC converter is 24 or 25 V. According to a preferred embodiment, the switching means are configured to conduct the operating energy from the AC/DC conve