Power storage system

Abstract

To avoid inconvenience when connecting an extension battery unit to a DC / DC converter by parallel connection to a main battery unit connected to a power conversion management device via the DC / DC converter.SOLUTION: An additional battery unit 40 connected to a main DC / DC converter 24 connected to a power conversion management device 22 in parallel with a main battery unit 30 is connected to the main DC / DC converter 24 via a low-output DC / DC converter 44.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power storage system, and more particularly to a power storage system including a battery unit connected to a power conversion management device via a DC / DC converter. [Background technology]

[0002] Conventionally, as this type of power storage system, a system has been proposed in which a power conversion management device (power conditioner) is expanded by connecting a plurality of storage battery units, each having a built-in DC / DC converter, in series (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-103909 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned power storage system does not take into consideration the possibility of connecting an expansion battery unit to a DC / DC converter in parallel with a main battery unit connected to a power conversion management device via a DC / DC converter.

[0005] The main purpose of the energy storage system disclosed herein is to avoid the inconvenience of connecting an expansion battery unit to a DC / DC converter in parallel with a main battery unit connected to a power conversion management device via a DC / DC converter. [Means for solving the problem]

[0006] The power storage system of the present disclosure employs the following measures to achieve the above-mentioned main object.

[0007] The power storage system of the present disclosure includes: A power storage system comprising: a power conversion management device connected to a three-phase AC wiring; a main DC / DC converter connected to the power conversion management device; and a main battery unit connected to the main DC / DC converter, an expansion battery unit connected in parallel to the main battery unit to the main DC / DC converter is connected to the main DC / DC converter via a low-output DC / DC converter; It is characterized by:

[0008] In the energy storage system disclosed herein, expansion battery units connected in parallel to the main battery unit are connected to the main DC / DC converter via a low-output DC / DC converter. This allows the voltage of the expansion battery units to be adjusted to match the voltage of the main battery unit, eliminating the need to modify the control or circuitry of the main DC / DC converter. As a result, it is possible to avoid the inconvenience of connecting expansion battery units to a DC / DC converter in parallel with a main battery unit connected to a power conversion management device via a DC / DC converter.

[0009] In the energy storage system of the present disclosure, the main battery unit may be connected to the main DC / DC converter via the low-power DC / DC converter. This allows the voltages of the main battery unit and the expansion battery units to be set as desired. In this case, the main battery unit may be integrated with the low-power DC / DC converter, and the expansion battery units may also be integrated with the low-power DC / DC converter. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing an outline of the configuration of a power storage system 20 according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, a mode (embodiment) for carrying out the present disclosure will be described. Fig. 1 is a configuration diagram showing an outline of the configuration of a power storage system 20 as one embodiment of the present disclosure. The power storage system 20 of the embodiment is a stationary battery system for general household use, and as shown in the figure, includes a main circuit 21, a main battery unit 30, and a plurality of expansion battery units 40.

[0012] The main circuit 40 has a power conversion management device 22 connected to three-phase AC wiring such as a three-phase AC power supply 26, and a main DC / DC converter 24 that adjusts the voltage. The power conversion management device 22 is mainly composed of an inverter and a filter, and is also connected to a solar power generation device 28, etc. The main DC / DC converter 24 is configured as a well-known bidirectional DC / DC converter, and is equipped with connection wiring 25 so that in addition to the main battery unit 30, multiple expansion battery units 40 can be connected in parallel.

[0013] The main battery unit 30 is configured by integrating a main battery 32, which is composed of a secondary battery such as a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and a low-output DC / DC converter 34, which is connected to the main battery 32 and also to the main DC / DC converter 24.

[0014] The multiple expansion battery units 40 are connected to the main DC / DC converter 24 via connecting wiring 25 so as to be in parallel with the main battery units 30. Like the main battery units 30, they are integrally configured with expansion batteries 42, which are made up of secondary batteries such as lithium-ion secondary batteries or nickel-metal hydride secondary batteries, and a low-output DC / DC converter 44, which is connected to the expansion batteries 42 and the main DC / DC converter 24.

[0015] Because the main battery unit 30 and multiple expansion battery units 40 are each connected to the main DC / DC converter 24 via low-output DC / DC converters 34, 44, even if the battery voltages differ, the low-output DC / DC converters 34, 44 can provide the same voltage for supplying and receiving power to the main DC / DC converter 24. As a result, there is no need to change the control of the main DC / DC converter 24 or modify the main circuit 21 each time an expansion battery unit 40 is added. Furthermore, even if a battery with a low battery voltage is added as an expansion battery unit 40, the voltage is increased by the low-output DC / DC converter 44 before being connected to the main DC / DC converter 24, so there is no need to design the main DC / DC converter 24 to be able to withstand large currents.

[0016] In the power storage system 20 of this embodiment, the main battery unit 30 is composed of a main battery 32 and a low-power DC / DC converter 34, and the expansion battery unit 40 is composed of an expansion battery 42 and a low-power DC / DC converter 44. However, while the expansion battery unit 40 is composed of an expansion battery 42 and a low-power DC / DC converter 44, the main battery unit 30 may not have the low-power DC / DC converter 34.

[0017] In the power storage system 20 of this embodiment, the main battery unit 30 is an integrated unit of a main battery 32 and a low-power DC / DC converter 34, and the expansion battery unit 40 is an integrated unit of an expansion battery 42 and a low-power DC / DC converter 44. However, the main battery 32 and the low-power DC / DC converter 34 may be separate units, and the expansion battery 42 and the low-power DC / DC converter 44 may also be separate units.

[0018] The correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problems" section will be explained below. In the embodiment, the power conversion management device 22 corresponds to the "power conversion management device," the main DC / DC converter 24 corresponds to the "main DC / DC converter," the main battery unit 30 corresponds to the "main battery unit," the expansion battery unit 40 corresponds to the "expansion battery unit," and the low-power DC / DC converter 44 corresponds to the "low-power DC / DC converter."

[0019] The correspondence between the main elements of the embodiments and the main elements of the invention described in the "Means for Solving the Problem" section does not limit the elements of the invention described in the "Means for Solving the Problem" section, since the embodiments are examples for specifically explaining the mode for implementing the invention described in the "Means for Solving the Problem" section. In other words, the interpretation of the invention described in the "Means for Solving the Problem" section should be based on the description in that section, and the embodiments are merely specific examples of the invention described in the "Means for Solving the Problem" section.

[0020] The present disclosure has been described above using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be embodied in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0021] The present disclosure is applicable to industries such as the manufacturing of power storage systems. [Explanation of symbols]

[0022] 20 Energy storage system, 21 Main circuit, 22 Power conversion management device, 24 Main DC / DC converter, 25 Connection wiring, 26 Three-phase AC power supply 28 Solar power generation device, 30 Main battery unit, 32 Main battery, 34 Low-output DC / DC converter, 40 Expansion battery unit, 42 Expansion battery, 44 Low-output DC / DC converter.

Claims

[Claim 1] A power storage system comprising: a power conversion management device connected to a three-phase AC wiring; a main DC / DC converter connected to the power conversion management device; and a main battery unit connected to the main DC / DC converter, an expansion battery unit connected in parallel to the main battery unit to the main DC / DC converter is connected to the main DC / DC converter via a low-output DC / DC converter; A power storage system characterized by:

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