Power storage system

Abstract

To provide a power storage system with improved assemblability and maintainability.SOLUTION: A power storage system 10 includes a housing 11, a bank in which a plurality of power storage elements L are connected in series, and a protection unit 100 that protects the plurality of power storage elements L from abnormality, wherein the plurality of banks are housed in the housing 11, and the plurality of protection units 100 provided for each of the plurality of banks are removably housed in the housing 11, and are arranged side by side in a lateral direction in the housing 11.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a power storage system. [Background technology]

[0002] Patent Document 1 discloses a container-type electricity storage unit in which a plurality of electricity storage modules are supported on a battery panel placed inside the container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6455282 Summary of the Invention [Problem to be solved by the invention]

[0004] In the field of industrial energy storage systems, a configuration in which multiple energy storage elements are connected in series to generate high voltages ranging from several hundred volts [V] to over 1000 V is called a bank. In Patent Document 1, a single control device placed inside a container controls the charging and discharging of multiple banks.

[0005] The need for energy storage systems is increasing to expand the use of renewable energy and promote energy management. There is a need to reduce the total cost of energy storage systems, including assembly and maintenance costs.

[0006] One embodiment of the present invention provides an energy storage system (ESS) with improved assembly and maintenance properties. [Means for solving the problem]

[0007] A storage system according to one aspect of the present invention comprises a housing, a bank formed by connecting a plurality of storage elements in series, and a protection unit that opens and closes the power line of the bank, wherein the plurality of banks are housed in the housing, and the plurality of protection units provided for each of the plurality of banks are each removably housed in the housing. [Effects of the Invention]

[0008] According to the above aspect, it is possible to provide a power storage system with improved assembly and maintenance properties. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a power storage system. [Figure 2] FIG. 2 is a block diagram showing the electrical configuration of the power storage system. [Figure 3] FIG. [Figure 4] FIG. 2 is a block diagram showing the electrical configuration of the protection unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] An outline of the embodiment will be described below.

[0011] (1) The energy storage system includes a housing, a bank formed by connecting a plurality of energy storage elements in series, and a protection unit that opens and closes the power line of the bank, wherein the plurality of banks are housed in the housing, and the plurality of protection units provided for each of the plurality of banks are each removably housed in the housing.

[0012] In this specification, the "energy storage element" may be an energy storage cell, or may be an energy storage module in which a plurality of energy storage cells are connected in series and / or in parallel. The power storage element may be a lithium ion battery, but is not limited to this, and may be another secondary battery that can be charged and discharged, or a capacitor.

[0013] The protection units provided in each bank to open and close the power lines of each bank are smaller and lighter than a single (large) protection device that opens and closes the power lines of multiple banks (see Figure 3). Using a small and lightweight protection unit makes it easier to house the protection unit in the housing, improving the assembly of the energy storage system. In addition, because each small and lightweight protection unit is removable, it is possible to replace only the protection unit that needs replacement, improving the maintainability of the energy storage system. By changing the number of series-connected energy storage elements, energy storage systems can be offered as products for voltages above 1000V or below 1000V. The protection units provided for each bank as described above are highly versatile and can be applied to multiple types of products with different voltage ranges. This allows for mass production benefits such as reduced costs and easier parts procurement.

[0014] (2) In the energy storage system of (1) above, the plurality of energy storage elements constituting each bank may be arranged vertically in the housing, the protection unit of each bank may be arranged above or below each bank, and the plurality of protection units may be arranged horizontally in the housing.

[0015] Energy storage systems may be assembled on-site, or assembled in a factory and transported to the installation site. In either case, multiple energy storage elements are connected to form high-voltage (e.g., around 1000V) electrical equipment, so to improve safety, it is desirable for energy storage systems to have an easy-to-understand design that prevents workers from making wiring mistakes. As in the above configuration, by arranging the multiple storage elements that make up each bank vertically and arranging the multiple protection units horizontally above or below those banks, it becomes easier for workers to intuitively understand the wiring work during assembly. By placing the protection unit for each bank above or below the bank, the wiring (e.g., wire harness) connecting the bank and protection unit can be shortened. This makes it easier to route the wiring. Also, during maintenance, it is easy for workers to understand the correspondence between the banks and protection units.

[0016] (3) In the power storage system of (1) or (2) above, each of the plurality of protection units may be configured to be applicable to a high-voltage product among a plurality of types of power storage system products having different voltage ranges. The protection units applied to high-voltage products (e.g., 1200V) in the product lineup have sufficient voltage resistance, so they can also be applied to low-voltage products (e.g., 600V), making them highly versatile. Such protection units bring about mass production benefits such as cost reduction and improved parts procurement. (4) In the energy storage system of (2) above, the protection unit may have a lateral dimension corresponding to the lateral dimension of the energy storage elements that make up each bank. "Corresponding" may mean that the dimensions are approximately the same, or may mean that the dimension is the sum of the lateral dimension of the energy storage element and the lateral dimension of the clearance between the banks.

[0017] By setting the horizontal dimension (width dimension) of the protection unit to such a value, when each bank is formed by arranging energy storage elements in a vertical row, multiple protection units can be arranged horizontally in the limited space within the housing above or below multiple banks.

[0018] (5) In any of the energy storage systems (1) to (4) above, each protection unit may have a support member having a front panel, positive and negative terminals provided on the front panel and to which the plurality of energy storage elements constituting the bank are electrically connected, and external positive and negative terminals provided on the front panel and to which an external circuit (main circuit, other bank) is electrically connected. In this specification, the term "terminal" includes a connector. The positive terminal, the negative terminal, and the external positive terminal and the external negative terminal are preferably configured as connectors, and the conductive parts are preferably not exposed to the outside.

[0019] By providing the positive terminal, negative terminal, external positive terminal, and external negative terminal on the front panel, workers can easily access these terminals even when the protection unit is stored in the housing, making wiring work easier during assembly and maintenance.

[0020] (6) In any of the energy storage systems (1) to (5) above, each protection unit may have an opening / closing part supported by the support member that opens and closes at least one of the power line between the positive terminal and the external positive terminal and the power line between the negative terminal and the external negative terminal.

[0021] By supporting the opening / closing section on the support member in advance, workers can implement the power line opening / closing function (protection function for the energy storage system) simply by wiring to the terminals on the front panel during assembly, improving the assembly ease of the energy storage system.

[0022] (7) In any one of the above-described power storage systems (1) to (6), each protection unit may include a management unit supported by the support member and configured to acquire a current flowing through the power line.

[0023] By having the support member support the management unit (e.g., battery management unit (BMU)) of each bank, there is no need for a dedicated member for supporting or storing the management unit. In addition, the assembly of the power storage system is improved.

[0024] (8) In the power storage system of (7) above, the switching unit may have a circuit breaker that can be opened and closed by an electric signal from the management unit. The circuit breaker may be a magnetic contactor or a relay.

[0025] By supporting the circuit breaker on the support member in advance and setting it to open and close in response to an electrical signal from the management unit, workers can implement the power line opening and closing function simply by wiring the terminals on the front panel during assembly, improving the assembly efficiency of the energy storage system. In applications such as absorbing fluctuations in renewable energy, multiple energy storage systems housed in containers or buildings are used. If the circuit breakers are of the manually closed type (such as molded case circuit breakers (MCCB)), workers must enter the container or building at the start of operation (when power is first applied), access each of the multiple energy storage systems, and manually close the circuit breakers of the multiple protection units within each energy storage system. In contrast, using circuit breakers that can be opened and closed by electrical signals from a management unit eliminates the need for workers to operate each protection unit, significantly simplifying the work required at the start of operation.

[0026] (9) In the power storage system of (8), the switching unit may include a fuse connected in series to the circuit breaker. A minimum breaking current of the fuse may be smaller than a maximum breaking current of the circuit breaker.

[0027] The switching unit has a fuse connected in series to the circuit breaker, so that the power line can be reliably cut off even when a large current is flowing. The minimum interrupting current of a fuse means the current required for the fuse to interrupt. The maximum interrupting current of a circuit breaker means the maximum current that the circuit breaker can interrupt. If a circuit breaker attempts to interrupt a current that exceeds its maximum interrupting current, an arc will occur between the circuit breaker contacts, making it unable to interrupt the current and potentially damaging the circuit breaker. By providing a fuse with a minimum breaking current smaller than the maximum breaking current of the circuit breaker, in the event of an abnormal event such as an external short circuit, the fuse can be melted first, and then the circuit breaker can open the current line. This configuration allows the power line to be opened (interrupted) with high reliability.

[0028] (10) A protection unit includes a support member having a front panel, a positive terminal and a negative terminal provided on the front panel and electrically connected to a storage element, an external positive terminal and an external negative terminal provided on the front panel and electrically connected to an external circuit, and a switching unit supported by the support member and configured to open and close at least one of a power line between the positive terminal and the external positive terminal and a power line between the negative terminal and the external negative terminal. The switching unit has a circuit breaker that can be opened and closed by an electric signal.

[0029] By using a circuit breaker that can be opened and closed by an electrical signal, workers do not need to operate each protection unit one by one, which significantly simplifies assembly and maintenance work.

[0030] (11) In the protection unit of (10) above, the front panel may further include a service plug that is provided between the middle storage elements of a bank formed by connecting a plurality of the storage elements in series and that opens and closes the power line of the bank.

[0031] By opening the service plug (cutting off the power line), even a 1200V energy storage system can be reduced to 750V or less, thereby improving safety during assembly and maintenance of the energy storage system. (12) The protection unit of (10) or (11) above may be configured to be applicable to a high-voltage product among a plurality of types of power storage system products with different voltage ranges.

[0032] Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0033] As shown in Fig. 1, the energy storage system 10 has a metal battery panel 11 as a housing, and a plurality of energy storage modules L are housed in the battery panel 11 as energy storage elements. The plurality of energy storage modules L are configured into a plurality of groups (banks) by wiring (not shown). The battery panel 11 shown in Fig. 1 houses three banks, each made up of energy storage modules L arranged in two vertical rows.

[0034] In the example of Fig. 1, each bank is configured by electrically connecting in series two vertical rows of a total of 18 energy storage modules L. The number of energy storage modules constituting each bank can be selected arbitrarily. For example, a bank may be configured by one and a half vertical rows of energy storage modules L or one vertical row of energy storage modules L.

[0035] The battery panel 11 has an opening / closing door on the front, and is provided with a plurality of plates (shelf plates) spaced apart vertically inside. Although not shown, an exhaust port is provided on the back wall of the battery panel 11. The housing is not limited to a battery panel 11 having such an opening / closing door (front wall), but may be a shelf with a plurality of plates spaced apart vertically so that the power storage module L can be seen from the front of the housing.

[0036] The power storage module L may be configured by connecting a plurality of power storage cells (for example, lithium ion battery cells) in series and / or parallel. The power storage cells may be square cells (prismatic cells), cylindrical cells, or laminated cells (pouch cells). The power storage module L has an elongated shape (for example, a rectangular parallelepiped shape) extending from the front surface of the battery panel 11 toward the rear wall. The power storage module L is inserted between the shelf plates from the front surface of the battery panel 11.

[0037] A protection unit 100 is disposed above each bank (for example, on the top shelf inside the battery panel 11). In the example of FIG. 1 where three banks are housed in the battery panel 11, three protection units 100 are disposed side by side inside the battery panel 11. Each protection unit 100 has an elongated shape that extends from the front face of the battery panel 11 toward the rear wall.

[0038] Although not shown, a connector or terminal is provided on the front surface of each storage module L for electrical connection with an adjacent storage module L or protection unit 100 in the vertical direction. Because the corresponding protection unit 100 is arranged directly above the bank, the wiring (e.g., wire harness) connecting the bank (the uppermost storage module L) and the protection unit 100 can be shortened, making it easier to manage the wiring. Furthermore, during assembly and maintenance, workers can easily understand the correspondence between the bank and the protection unit 100.

[0039] The energy storage system 10 of this embodiment can be provided as a product for different voltage ranges by changing the number of energy storage modules L that make up one bank. For example, as shown in FIG. 1 , a 1200V energy storage system 10 can be provided by connecting two vertical rows of energy storage modules L in series to form one bank and storing three banks in the battery panel 11. In the example of FIG. 1 , the dimensions of the battery panel 11 are set so that the battery storage space is almost full when three banks made up of two vertical rows of energy storage modules L are stored. Three corresponding protection units 100 are removably stored in the battery panel 11 above the three stored banks.

[0040] Although not shown, if a single, integrated (large) protection device that protects all three banks is to be housed in the battery panel 11, the assembly work becomes cumbersome because such a protection device is large and heavy. In particular, if the protection device is to be housed in the upper part of the battery panel 11, the burden on the worker is heavy. In comparison with such cases, the three protection units 100 provided for each bank as shown in Figure 1 are each small and lightweight, and can be easily stored above the battery panel 11. Furthermore, because each protection unit 100 is detachable, it is possible to replace only the protection unit 100 that needs to be replaced.

[0041] Although not shown, by reducing the number of storage modules L that make up a bank, it is possible to provide products in different voltage ranges such as 600V, 750V, and 900V. For example, in the case of a 600V energy storage system 10, one bank is formed by connecting energy storage modules L in series in one vertical row. To improve the energy density of the energy storage system 10, six banks are housed in the battery panel 11. In this case, six corresponding protection units 100 are housed in the battery panel 11 above the six housed banks, and each protection unit 100 is removably housed in the battery panel 11.

[0042] The protection unit 100, which is applied to the highest voltage product (1200V) in the product lineup, has sufficient voltage resistance and is therefore also applicable to products in the low voltage range (for example, 600V), making it highly versatile. Such protection unit 100 can be applied to multiple types of products in different voltage ranges, resulting in mass production benefits such as cost reduction and improved parts procurement.

[0043] Furthermore, the protection unit 100 as shown in FIG. 1 is smaller and lighter than an integrated (large) protection device, and therefore can be produced by a small number of workers and is easy to produce. Integrated protection devices must be manufactured separately for 1200V products (where three banks are housed in the battery panel 11) and 600V products (where six banks are housed in the battery panel 11). It is necessary to stock multiple types of protection devices of different sizes on the production line. In contrast, the protection unit 100 in Figure 1 can be applied to products of different voltage ranges with the same specifications, making it easy to handle on the production line and easy to stock. Therefore, the protection unit 100 contributes to reducing the production cost of the power storage system 10.

[0044] As described above, when one bank is formed by connecting a row of energy storage modules L in series in the vertical direction, six banks and six protection units 100 are housed in the battery panel 11. The horizontal dimension (width dimension) of each protection unit 100 is set to correspond to the width dimension of the energy storage modules L of each bank. For example, the width dimension of the protection unit 100 is set to a value calculated from the following formula. Protection unit width dimension ≦ (Module width dimension + Bank clearance width dimension) By setting the width dimension of the protection unit to such a value, when each bank is formed by arranging the energy storage elements in a vertical row, six protection units 100 can be arranged horizontally in the limited space within the housing above or below the bank.

[0045] FIG. 2 shows the electrical configuration of the energy storage system 10. The protection unit 100 is not shown in FIG. 2. The energy storage modules L are connected in series to form a bank. As described above, in this embodiment, three banks are housed in one battery panel. The energy storage system 10 has a hierarchical structure of banks and domains in which a plurality of banks are connected in parallel. The power line of each bank is connected to a main circuit line (for example, a bus bar capable of carrying a large current) not shown.

[0046] In the example of FIG. 2, one management unit 1 is provided for each bank and one for each domain. When distinguishing between the management unit 1 provided in a bank and the management unit 1 provided in a domain, the former will be referred to as management unit 1B and the latter as management unit 1D. The management unit 1B provided in each bank communicates with a control board (Cell Management Unit) L1 with a communication function built into the power storage module L in the bank via serial communication via a communication line 119. The management unit 1B acquires status data (measurement data, such as cell voltage and module voltage) of the power storage cells inside the power storage module L. The management unit 1B also acquires temperature data measured in the power storage module L and current data measured for each bank. The management unit 1B may perform management processes such as detecting abnormalities in the communication state.

[0047] The management unit 1D provided in the domain can communicate with the management unit 1B of the bank via a communication bus 120. The communication bus 120 is, for example, a CAN bus. Alternatively, the communication bus 120 may be a LAN cable or a communication medium compatible with ECHONET / ECHONET Lite (registered trademark).

[0048] The management unit 1D of the domain may aggregate the status data acquired by the management units 1B of the bank. A communication device 4 is connected to the management unit 1D of the domain. The communication device 4 transmits the status data acquired from each management unit 1B via the management unit 1D.

[0049] The communication device 4 may be a terminal device (measurement monitor) that communicates with the management unit 1 to receive information about the power storage elements, or may be an ECHONET / ECHONETLite compatible controller. The communication device 4 may be an independent device, such as a router-type communication device, or may be a network card-type device (network interface card).

[0050] The communication device 4 receives an instruction from an external device (for example, a terminal of an operator) and can cause each management unit 1B to open or close an electromagnetic contactor, which will be described later.

[0051] As shown in Fig. 3, the protection unit 100 has a support member 101 having a front panel 101a. In the protection unit 100 of this embodiment, the front panel 101a and a bottom panel 101b extending in a direction perpendicular to the front panel 101a (from the front surface of the battery panel 11 toward the rear wall) are integrally formed from sheet metal. The management unit 1B is supported on the bottom panel 101b. No panel is provided above the opposite side of the bottom panel 101b, thereby reducing the weight of the protection unit 100.

[0052] A positive terminal connector 102 and a negative terminal connector 103 are provided on the surface of the front panel 101a, to which the positive power line and negative power line of the storage modules L that make up the bank are respectively connected. The positive terminal connector 102 has a resin-molded positive terminal, and the negative terminal connector 103 has a resin-molded negative terminal. An external terminal connector 105 to which a main circuit line (not shown) is electrically connected is provided on the surface of the front panel 101a. The main circuit line is an example of an external circuit of the protection unit 100. The main circuit line may be a bus bar disposed inside the battery panel 11. The external terminal connector 105 has an external positive terminal and an external negative terminal molded with resin.

[0053] The positive terminal connector 102, the negative terminal connector 103, and the external terminal connector 105 have no exposed conductive parts, allowing workers to perform wiring work safely. The external terminal connector 105 has a different shape from the positive terminal connector 102 and the negative terminal connector 103, which prevents incorrect wiring.

[0054] An intermediate terminal connector 104 is provided on the surface of the front panel 101a. The intermediate terminal connector 104 is connected to a power line between two intermediate power storage modules L that form a bank. The intermediate terminal connector 104 has an intermediate terminal molded with resin. The intermediate terminal connector 104 has a different shape from the positive terminal connector 102, the negative terminal connector 103, and the external terminal connector 105, which prevents incorrect wiring. In addition, a service plug 106 is provided on the surface of the front panel 101a.

[0055] Two CAN communication connectors 107 are provided on the surface of the front panel 101a. Furthermore, on the surface of the front panel 101a, a receiving communication connector 108a and a transmitting communication connector 108b are provided for serial communication with the control board L1 of each power storage module L in the bank.

[0056] A handle 101c is provided on the surface of the front panel 101a. When assembling the power storage system 10, a worker supports the lower panel 101b from below and holds the handle 101c to place the protection unit 100 on the top shelf shown in FIG. 1, and the upper side of the protection unit 100 is covered by the upper wall of the battery panel 11. In the state shown in FIG. 1, the worker can access the front panel 101a of the protection unit 100. The worker electrically connects the bank and the protection unit 100, and the main circuit line and the protection unit 100, via the positive terminal connector 102, the negative terminal connector 103, the external terminal connector 105, and the intermediate terminal connector 104. Since no conductive parts such as terminal blocks are exposed on the surface of front panel 101a, workers can safely perform wiring work.

[0057] By having the support member 101 support the management unit 1B, there is no need for a dedicated member for supporting or storing the management unit 1B. By storing the protection unit 100 in the battery panel 11, the installation of the management unit 1B is completed, improving the ease of assembly of the electricity storage system 10.

[0058] Figure 4 shows the electrical configuration of the protection unit 100. The lower panel 101b of the support member 101 is provided with an opening / closing unit that opens and closes the positive power line between the positive terminal connector 102 and the external terminal connector 105. The lower panel 101b also is provided with an opening / closing unit that opens and closes the negative power line between the negative terminal connector 103 and the external terminal connector 105, and a current sensor 117 (e.g., a Hall sensor) that detects the current flowing through the negative power line. In Figure 4, the symbol S denotes a signal line.

[0059] The switching section is composed of an electromagnetic contactor 110 that can be opened or closed by an electric signal from the management unit 1B, and a fuse 112 connected in series to the electromagnetic contactor 110. The electric signal from the management unit 1B is given to each electromagnetic contactor 110 via an LED board 115. The open / closed state of the electromagnetic contactors 110, i.e., the current-carrying state of the bank, cannot be directly seen from the front as shown in Fig. 1. Therefore, when both electromagnetic contactors 110 are closed (on), an LED 119 provided on the front panel 101a lights up to indicate to the outside that the bank is in a current-carrying state.

[0060] By supporting such an opening / closing section in advance on the support member 101, the worker can implement the power line opening / closing function (protection function for the energy storage system 10) during assembly simply by wiring to the terminal connector on the front panel 101a.

[0061] In this embodiment, electromagnetic contactors 110 that can be opened and closed by an electric signal from the management unit 1B are used. By giving an ON command to the communication device 4 (see FIG. 2) from an operator's terminal (PC or tablet), all of the electromagnetic contactors 110 in the power storage system 10 can be turned ON. If a manually closed MCCB is used as the switching part, an operator needs to operate each protection unit 100 one by one when starting operation of the energy storage system 10. When a large number of energy storage systems 10 are installed, this operation becomes very cumbersome. According to this embodiment, the operation when starting operation (or when starting power supply after maintenance) is significantly simplified.

[0062] The minimum breaking current of the fuse 112 shown in FIG. 4 is set to be smaller than the maximum breaking current of the electromagnetic contactor 110. By providing a fuse 112 whose minimum breaking current is smaller than the maximum breaking current of the electromagnetic contactor 110, when an abnormal event such as an external short circuit occurs, it becomes possible to first melt the fuse 112 and then open the current line using the electromagnetic contactor 110. With this configuration, the power line can be turned off (shut off) with high reliability.

[0063] As shown in Fig. 4, a service plug 106 is provided on the front panel 106. The service plug 106 is disposed between two power storage modules L in the middle of a bank made up of multiple power storage modules L, and opens and closes the power line of the bank. Although Fig. 4 shows the service plug 106 in an off state, the service plug 106 is on when the power storage system 10 is in operation.

[0064] By turning off the service plug 106 (cutting off the power line), even a 1200V power storage system can be reduced to 750V or less, thereby improving safety during assembly and maintenance of the power storage system. The LED 119 provided on the front panel 101a may be configured to light up when both the electromagnetic contactors 110 and the service plug 106 are closed (turned on).

[0065] The present invention is not limited to the above-described embodiments. Instead of the power storage module L, a long power storage cell extending from the front surface to the back surface of the battery panel 11 (housing) may be housed in the housing as the power storage element. The opening and closing section may be provided on the front or rear surface of the front panel of the support member. The opening and closing section is not limited to one that can be opened and closed by an electrical signal from the management unit. [Explanation of symbols]

[0066] L Energy storage module (energy storage element) 10 Energy storage system 11 Battery panel (casing) 100 Protection Units

Claims

1. The housing and a bank configured by connecting a plurality of storage elements in series; a protection unit that protects the plurality of storage elements from abnormalities, a plurality of the banks are housed in the housing and connected in parallel within the housing, and the plurality of power storage elements constituting each bank are arranged side by side in a vertical direction within the housing; a plurality of the protection units provided for each of the plurality of banks are removably housed in the housing, the protection unit of each bank is disposed above or below the corresponding bank, and the plurality of protection units are disposed side by side in the housing; the lateral dimension of each protection unit housed in the housing corresponds to the lateral dimension of each storage element housed in the housing; Energy storage system.

2. Three or more of the banks are housed in the housing, the storage elements arranged side by side in the vertical direction in the housing to form one bank and the storage elements arranged side by side in the vertical direction in the housing to form another bank face each other in the horizontal direction across an inter-bank clearance, The power storage system according to claim 1 .

3. Three or more of the protection units are housed in the housing, and one protection unit faces another protection unit across a clearance in the lateral direction. The power storage system according to claim 2 .

4. Each of the protection units has a display unit on its front surface that indicates the power supply status of the corresponding bank. The power storage system according to claim 3 .

5. the energy storage element has an elongated shape extending from the front surface to the rear surface of the housing, the housing is made of metal and has a plurality of plates spaced apart in a vertical direction; The plurality of plates support the plurality of energy storage elements from below across the front and rear surfaces of the housing. The power storage system according to claim 2 .

6. The housing has an opening / closing door on its front surface and an exhaust port on its rear surface. The power storage system according to claim 5 .

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