Electrochemical Energy Storage Devices

Abstract

The present invention relates to an electrochemical energy storage device comprising a plurality of electrochemical cells (15) in a storage space in a housing (3), the electrochemical energy storage device (1) comprising a first duct extending parallel to the top or bottom of the housing (3) and one or more heat transfer members (17) arranged in a space (19) between the electrochemical cells (15), at least one of the heat transfer members (17) protruding into the first duct (21).

Description

[Technical field]

[0001] The present invention relates to an electrochemical energy storage device comprising a plurality of electrochemical cells within a housing, each electrochemical cell comprising an anode space and a cathode space separated by a solid electrolyte. [Background technology]

[0002] Electrochemical energy storage devices are also commonly called batteries or accumulators. In particular, rechargeable batteries or rechargeable accumulators allow electrical energy to be stored and used. To store large amounts of electrical energy, correspondingly powerful rechargeable batteries are required. For this purpose, it is possible to use batteries based on molten sodium and sulfur, for example. To achieve the corresponding capacity, electrochemical energy storage devices generally use several electrically interconnected electrochemical cells. Such electrochemical cells operating on a molten alkali metal as anode and a cathode reactant (generally sulfur) are described, for example, in WO-A 2017 / 102697. Here, the molten alkali metal and the cathode reactant are separated by a solid electrolyte that allows the passage of cations. At the cathode, a reaction takes place between the alkali metal and the cathode reactant. If sodium is used as the alkali metal and sulfur is used as the cathode reactant, this is, for example, a reaction of sodium with sulfur, forming sodium polysulfide. To charge the electrochemical energy storage device, application of electrical energy causes the sodium polysulfide to decompose back into sodium and sulfur at the electrodes.

[0003] The individual electrochemical cells are generally stacked in a "battery pack" or, alternatively, arranged parallel to one another in a housing. However, such an arrangement has the disadvantage that uniform temperature control of the individual cells is difficult. The throughflow of the heat transfer medium, especially if it flows perpendicular to the orientation of the electrochemical cells, causes a temperature increase of said heat transfer medium due to the absorption of heat by the heat transfer medium from the individual cells, with an increase in the distance traveled by the flowing heat transfer medium, thus reducing the cooling and accelerating the deterioration of the electrochemical cells. However, this is detrimental to the operation of the electrochemical energy storage device. In particular, there is a risk of damage to the individual electrochemical cells if the temperature increase is too great. This damages the solid electrolyte, which can lead to uncontrollable reactions, which can lead to fires that are difficult to control in electrochemical energy storage devices.

[0004] Corresponding energy storage devices comprising sodium-sulfur batteries are described, for example, in JP-A 2000-297989 or US-B 7,955,725.

[0005] Providing uniform temperature control is a challenge for known electrochemical energy storage devices. To achieve uniform temperature control, WO-A 2019 / 206864 proposes an electrochemical energy storage device in which at least one electrochemical cell is accommodated in a suspended manner in a support structure. However, arranging the electrochemical cells in a suspended manner as described in WO-A 2019 / 206864 requires a complex design. Furthermore, accommodating the electrochemical cells in a suspended manner has the disadvantage that the density at which the electrochemical cells can be loaded is limited.

[0006] To control the temperature of a sodium-sulfur battery, it is known, for example from EP-A 0 044 753 or US 5,158,841, to provide the battery with tubes running parallel to the battery cells and through which a heat transfer medium flows. US-A 2018 / 0062225 and US-A 2021 / 0075076 each describe the use of cooling fins in contact with the individual cells to control the temperature. Due to the necessary distributors and collectors, cooling tubes through which a heat transfer medium, for example air, flows are technically complex to realize. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide an electrochemical energy storage device which allows controlling the temperature of the electrochemical cells with little technical effort and which allows sufficient heat transfer. [Means for solving the problem]

[0008] This object is achieved by an electrochemical energy storage device comprising a plurality of electrochemical cells in a storage space in a housing, the electrochemical energy storage device comprising a first duct extending parallel to the top or bottom of the housing and one or more heat transfer members arranged in the space between the electrochemical cells, at least one of the heat transfer members protruding into the first duct.

[0009] By arranging the electrochemical cells and the heat transfer members preferably in a parallel arrangement, the distance between the electrochemical cells and the heat transfer members can be minimized, optimizing the heat transfer, and this arrangement also allows for a uniform temperature throughout the electrochemical energy storage device.

[0010] The heat transfer member may be any type of heat transfer member, for example an electric element such as a Peltier element or an electric heating element. Particularly preferably, however, a heat transfer member having the shape of a plate, a solid rod or a hollow pipe is used. In this case, heat is transferred from the electrochemical cell to the heat transfer member and, in the heat transfer member, by thermal conduction, to at least one end of the heat transfer member and to a first duct through which a heat transfer medium, in particular air, can flow. Besides air, the heat transfer medium may be, for example, thermal oil or nitrogen. Particularly preferably, however, the heat transfer medium is air.

[0011] The shape of the heat transfer member is arbitrary. Preferably, the heat transfer member is a plate, a solid rod or a pipe having any cross-sectional shape, such as a circle, an ellipse, or a polygon having any number of sides, preferably 3 to 8 sides. Particularly preferably, the heat transfer member is a plate, a solid rod or a pipe having a circular cross-sectional shape.

[0012] In order to achieve sufficient heating or cooling of the electrochemical cells, when the heat transfer member is pipe-shaped, the ratio of the number of electrochemical cells to the number of heat transfer members is in the range of 4:1 to 1:10, more preferably the ratio of the number of electrochemical cells to the number of heat transfer members is in the range of 2:1 to 1:1, in particular 1:1. Thus, the ratio of the number of electrochemical cells to the number of heat transfer members depends on the size and shape of the electrochemical cells and the size and shape of the heat transfer member.

[0013] Preferably, the electrochemical cells are arranged to form a square lattice in a plan view, and the heat transfer members are arranged at the centers of the unit cells of the square lattice, and more preferably, the heat transfer members are in contact with four of the cells constituting the unit cell.

[0014] Regardless of the arrangement of the electrochemical cells and the heat transfer member, each heat transfer member may be arranged such that the distance between the heat transfer member and each of its neighboring electrochemical cells is the same. In this case, the heat transfer member is located in the center of the space between the electrochemical cells. If the electrochemical cells are not in contact with the heat transfer member, it is also possible for the distance between the heat transfer member and the neighboring electrochemical cells to be different. If the distance between the heat transfer member and the neighboring electrochemical cells is different, the heat transfer member is arranged off-center. However, preferably, the heat transfer member is arranged centrally.

[0015] When the heat transfer member is in the form of a plate, it is preferred that the electrochemical cells are arranged in rows and the heat transfer member is positioned between the rows of electrochemical cells.

[0016] Besides using a heat transfer element in the form of a pipe or a heat transfer element in the form of a plate, it is further possible to use heat transfer elements of different shapes, for example a heat transfer element in the form of a pipe inside the electrochemical energy storage device and a heat transfer element in the form of a plate arranged close to the wall of the housing and running parallel to the wall of the housing. In the case of a heat transfer element in the form of a plate arranged parallel to the wall of the housing, it is further possible to arrange the heat transfer element in the space between the outermost electrochemical cell and the wall of the housing.

[0017] The electrochemical cells preferably each comprise a compartment for an anodic material and a compartment for a cathodic material, the compartments for the anodic material and the compartments for the cathodic material being separated by a solid electrolyte.

[0018] The anode material used in the electrochemical cell is preferably liquid at the operating temperature of the electrochemical cell and is the reactant supplied to the anode side during discharge. The anode material is preferably electrically conductive. Preferred anode materials are alkali metals such as lithium, sodium or potassium. Particularly preferred is the anode material sodium or potassium, especially sodium.

[0019] The cathode material is a reactant that is liquid at the operating temperature of the electrochemical cell and that electrochemically reacts with the anode material. The cathode material conventionally forms a salt by chemical reaction with the anode material. Suitable cathode materials are, for example, sulfur and polysulfides. Also suitable as cathode materials are mixtures of sodium chloride with a group 8 transition metal, for example iron, nickel or cobalt, and a liquid-molten electrolyte, such as NaAlCl4.

[0020] Other suitable cathode materials in combination with alkali metals as anode materials are, for example, oxides of nitrogen (NO or NO2), halogens such as chlorine, iodine or bromine, metal halides such as NiCl2 or FeCl3, metalloid halides such as SiCl4 or Si2Cl6. It is also possible to use solid salts that can change the redox potential. An example of such a salt is NaFePO4.

[0021] However, particularly preferably the cathode material is sulfur or a polysulfide.

[0022] The electrochemical energy storage device preferably comprises electrochemical cells having a diameter to length ratio in the range of 1:2 to 1:100, more preferably in the range of 1:3 to 1:70, especially in the range of 1:4 to 1:50.

[0023] The cross-section of the electrochemical cell may be of any shape, although a cylindrical cross-section is particularly preferred.

[0024] In the context of the present invention, when the term "diameter" is used for a non-cylindrical shape, this term means

number

[0025] The number of cells used in the electrochemical energy storage device depends on the size of the electrochemical cell. Particularly preferably, the electrochemical cells used in the electrochemical energy storage device are sodium-sulfur cells. Such sodium-sulfur cells are usually cylindrical and have a diameter in the range of 6 to 20 cm and a length in the range of 50 to 200 cm. Corresponding sodium-sulfur cells are known to the person skilled in the art and are described, for example, in WO-A2017 / 102697.

[0026] To achieve sufficient heat transfer from the electrochemical cell to the heat transfer member, the heat transfer member and the electrochemical cell may be in contact, or the electrochemical cell and the heat transfer member may not be in contact, or only a portion of the electrochemical cell and the heat transfer member may be in contact.

[0027] The space between the heat transfer member and the electrochemical cell may be filled with a liquid or solid material, regardless of whether the electrochemical cell is in contact with the heat transfer member or not. If the space is filled with a solid material, it is particularly preferred that the solid material is a particulate material, in particular a powdery material. The average particle size of the particles of the particulate material is preferably in the range of 0.1-2 mm, more preferably in the range of 0.5-1 mm. The solid material used to fill the space between the electrochemical cell and the heat transfer member is preferably any inorganic solid material that is stable at the operating temperature, such as sand, glass, metal or ceramic. A particularly preferred material is sand. Filling the space between the electrochemical cell and the heat transfer member has the additional advantage that the heat transfer from the electrochemical cell to the heat transfer member is improved.

[0028] The use of a solid material to fill the space between the electrochemical cells and the heat transfer member has the additional effect that the position of the electrochemical cells is stable and the electrochemical cells are fixed. Even if the electrochemical energy storage device moves, the electrochemical cells stay in their position and do not bounce against each other, which may result in damage to the electrochemical cells. Therefore, it is particularly preferred to use a solid material to fill the space between the electrochemical cells and the heat transfer member. The use of sand as a solid material to fill the space between the electrochemical cells has the additional advantage that the solid material acts as a fire extinguishing agent in case the electrochemical cells are damaged.

[0029] Typically, the electrochemical cells generate heat during operation. This heat is dissipated by the heat transfer member, which in this case acts as a cooling element. In addition, part of the heat is dissipated to the surroundings through the outer wall of the electrochemical energy storage device. Due to the additional heat dissipation to the surroundings, the electrochemical cells closer to the wall of the electrochemical energy storage device will be cooler than the electrochemical cells closer to the center of the electrochemical energy storage device due to the uniform cooling of all the electrochemical cells. Therefore, in order to uniformize the temperature of all the electrochemical cells, it is necessary to dissipate more heat from the electrochemical cells located closer to the center of the electrochemical energy storage device than from the electrochemical cells located closer to the wall. This can be achieved, for example, by designing the heat transfer member such that the surface area of ​​the outer heat transfer member located closer to the wall of the housing is smaller than the surface area of ​​the inner heat transfer member located in the center of the housing, or such that the volumetric flow rate of the heat transfer medium through the heat transfer member located closer to the wall of the housing is smaller than the volumetric flow rate of the heat transfer medium through the heat transfer member located in the center of the housing. Preferably, the heat transfer members are designed such that the ratio of the surface area of ​​the outer heat transfer member to the surface area of ​​the inner heat transfer member is in the range of 0.1 to 1.

[0030] If the heat transfer member is a plate extending from one wall of the housing to the opposite wall of the housing, the wall thickness of the plate can be varied to achieve a uniform temperature in the adjacent electrochemical cells. For such a uniformization of the temperature in the electrochemical cells, it is particularly preferred that the walls of the plate closer to the wall of the housing are thicker. Furthermore, in order to achieve a uniformization of the temperature of the electrochemical cells, it is also possible to provide separate plates with a larger distance between the opposing walls of the plate in the central area of ​​the housing of the electrochemical energy storage device and a smaller distance between the walls closer to the wall of the housing.

[0031] It is also possible to provide heat transfer members in more than two different sizes, for example three, four or even more different sizes. The number of different sizes depends on the number of electrochemical cells and the arrangement of the cells. For example, more than two different sizes may be advantageous if it is not possible to achieve an essentially uniform temperature within the housing.

[0032] According to the invention, the electrochemical energy storage device comprises a first duct running parallel to the top or bottom of the housing and into which the heat transfer member projects, this design enhances the heat transfer from the heat transfer member to the heat transfer medium, preferably air, flowing through the first duct.

[0033] Furthermore, the electrochemical energy device may also comprise a second duct located at the bottom of the housing if the first duct is located at the top of the housing, or at the top of the housing if the first duct is located at the bottom of the housing.

[0034] If the electrochemical energy device comprises an additional second duct, the heat transfer member is preferably connected to the second duct or extends into the second duct.

[0035] In particular, to initiate charging or discharging of the electrochemical energy device, it may be necessary to heat the electrochemical energy device, and preferably a heater is located near the wall of the housing at the bottom below the cells, above the cells, or a combination thereof. If a bottom heater is used, it is further preferred that the lower end of the heat transfer member terminates above the bottom heater.

[0036] To facilitate the installation of the electrochemical energy device, the housing preferably comprises a box with an opening and a lid for closing the opening. It is further preferred that the box and the lid have thermal insulation properties, in particular to reduce the heat transferred to the surroundings during heating of the electrochemical cell. For this purpose, the box and the lid can be equipped with a thermal insulation material attached to the outside of the box or to the inside of the wall of the box. The thermal insulation material can be any thermal insulation material known to the person skilled in the art, such as mineral wool, glass wool or other inorganic microporous thermal insulation material.

[0037] Preferably, the first duct is located above the electrochemical cell, between the box and the lid, which allows easy assembly of the electrochemical cell and also allows easy access to the first duct, for example for maintenance purposes.

[0038] At least one heat transfer element protrudes into the first duct for transferring heat to the medium flowing through the first duct. Particularly preferably, all heat transfer elements have the same length, whereby all heat transfer elements protrude into the first duct.

[0039] When the heat transfer member protrudes into the first duct, the heat transfer member protruding into the first duct may be in contact with a surface of the first duct opposite the storage space in the extension direction of the heat transfer member.

[0040] In order to improve heat transfer, it is preferable that the electrochemical energy storage device further includes a first intake fan capable of supplying air from the outside to the first duct, and the first duct includes a first intake port through which air is supplied from the first intake fan, a first internal space through which heat is transferred from the heat transfer member to the air supplied from the first intake port, and a first exhaust port through which the air that has passed through the first internal space is discharged to the outside.

[0041] In particular, when a second duct is provided at the bottom of the electrochemical energy storage device, the electrochemical energy storage device further includes a second intake fan capable of supplying air from the outside to the second duct, and the second duct includes a second intake port to which air is supplied from the second intake fan, a second internal space to which air is supplied from the second intake port, a second internal space in which the bottom heater is disposed so as to be interposed between the second internal space and the range in which the heat transfer member is disposed in the accommodation space, and a second exhaust port through which the air that has passed through the second internal space is exhausted to the outside. In this case, the air flowing through the second duct transfers heat to the second duct, and the air that has exited the second duct dissipates this heat to the surroundings by the air flowing through the second duct, thereby improving the cooling of the electrochemical cells.

[0042] Typically, heat is dissipated to the surroundings by the walls of the housing of the electrochemical energy storage device, so that electrochemical cells closer to the walls of the housing require less cooling than electrochemical cells in the centre of the housing, and the inner heat transfer member closer to the centre of the housing and the outer heat transfer member closer to the walls of the housing can project into different fluid circuits within the first duct.

[0043] In addition to providing only two fluid circuits, it is also possible to provide more than two fluid circuits, which allows each fluid circuit to be operated with different parameters, thus allowing for more specific setting of the heat transfer parameters in the electrochemical energy storage device.

[0044] If the first duct and / or the second duct comprise several closed fluid circuits, each fluid circuit may comprise at least one external heat exchanger connected to an inlet to a sub-duct of the first duct and / or the second duct, in order to control the temperature. If the fluid circuits are open fluid circuits, the first duct and / or the second duct may each be connected to at least one blower and, if further heating is required, heating elements may also be provided between and / or at the heat transfer members, the first duct and / or at the inlet to the first duct.

[0045] For sufficient heat transfer, the heat transfer member is preferably made of a material having good heat conduction properties. Suitable materials for the heat transfer member may be made of one or more metals selected from the group consisting of aluminum, copper, steel, and alloys containing at least one of these metals. [Brief description of the drawings]

[0046] Exemplary embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

[0047] In the figure, [Figure 1] FIG. 1 shows an electrochemical energy storage device having a temperature control circuit shown diagrammatically. [Diagram 2] FIG. 1 is a schematic cross-sectional view of an electrochemical energy storage device. [Diagram 3] FIG. 3 is a plan view of the electrochemical energy storage device according to FIG. 2. [Figure 4] 11A-11C show different arrangements of the upper end of the heat transfer member. [Diagram 5] 11A-11C show different arrangements of the upper end of the heat transfer member. [Figure 6] 11A-11C show different arrangements of the upper end of the heat transfer member. [Figure 7] FIG. 2 is a top view of an electrochemical cell of an electrochemical energy storage device and a heat transfer member which is a plate. [Figure 8] FIG. 2 is a top view of an electrochemical cell of an electrochemical energy storage device and a heat transfer member, which in a first embodiment is a pipe. [Figure 9] FIG. 2 is a top view of an electrochemical cell of an electrochemical energy storage device and a heat transfer member, which in a second embodiment is a pipe. [Figure 10] FIG. 1 shows a triangular lattice electrochemical cell arrangement. [Figure 11] FIG. 13 is a diagram showing temperature distribution as a result of a simulation calculation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] Detailed Description of the Drawings FIG. 1 shows an electrochemical energy storage device with a temperature control circuit, shown diagrammatically.

[0049] The electrochemical energy storage device 1 comprises a housing 3 enclosing the electrochemical cells and the heat transfer members. In order to improve the energy efficiency of the electrochemical energy storage device 1, it is preferred that the housing 3 is embodied in an insulated manner. Here, the insulation can be applied to the inside, or to the individual housing walls, or to the outside. Alternatively, it is also possible for the housing 3 to be manufactured from an insulating material. By way of example, the housing 3 can be manufactured from a metal sheet, in particular a steel sheet, insulated on the inside or outside. In this case, any desired insulating material known to the person skilled in the art can be used for the insulation. Alternatively, it is also possible to manufacture the housing from a mineral material, such as masonry. However, the advantage of a housing 3 made of steel sheet is that in this case a transportable electrochemical energy storage device 1 can be provided, whereas an electrochemical energy storage device 1 at a fixed location can also be surrounded by a housing 3 of bricks.

[0050] The housing has an inlet 5 and an outlet 7 for the heat transfer medium. The heat transfer medium may flow from top to bottom as shown here or alternatively from bottom to top. Preferably, the inlet is connected to a distributor by which the heat transfer medium is distributed to heat transfer members running parallel to the electrochemical cells in the housing 3. To remove the heat transfer medium from the electrochemical energy storage device 1, the heat transfer members are connected to a collector which is connected to the outlet 7. As an alternative to the embodiment shown in FIG. 1 with the distributor above the electrochemical cells and the collector below the electrochemical cells, both the distributor and the collector can be located above or below the electrochemical cells, preferably above the electrochemical cells.

[0051] If it is intended to provide at least two fluid circuits for the heat transfer medium, each fluid circuit comprises an inlet 5 and an outlet 7 connected to the heat transfer members of the respective fluid circuit.

[0052] To control the temperature, the heat transfer medium removed from the housing 3 via the outlet 7 then passes through a heat exchanger 9, a heating device 11 and a delivery device 13 and is then reintroduced into the housing 3 via the inlet 5. In this case, the heat exchanger 9, the heating device 11 and the delivery device 13 are preferably arranged in a channel, which can be embodied as a pipe or as a channel with any other cross section, for example a rectangular channel.

[0053] The heat exchanger 9 is used to cool the heat transfer medium, especially when the heat transfer medium is used to cool an electrochemical cell, for example in the case of an alkali metal-sulfur cell, as is necessary during the charging and discharging process. During this process, the heat transfer medium in the heat exchanger 9 gives up heat to another heat transfer medium, where for example water or any other desired conventional heat transfer medium, for example thermal oil, can be used as the heat transfer medium.

[0054] If it is necessary to supply heat for the operation of the electrochemical cell or for the start-up of the electrochemical cell, a heating device 11 is provided. In the heating device 11, a heat transfer medium is heated. Here, the heating can be achieved directly or indirectly, indirect heating is achieved, for example, by using a heat medium which releases heat to the heat transfer medium in order to control the temperature of the electrochemical cell. However, here it is only possible to use a heat medium which is stable at a temperature higher than the temperature to which the heat transfer medium for heating the electrochemical cell is to be heated. Suitable heat media are, for example, molten salts. It is therefore preferable to use a heating device in which the heat transfer medium is heated electrically or inductively or by burning a fuel.

[0055] As an alternative to the embodiment shown here with a heat exchanger 9 for cooling and a separate heating device 11, it is also possible to use just one heat exchanger used for both heating and cooling. For this purpose, the temperature of the heat transfer medium can be changed either for heating or for cooling, or a combined unit is used which includes cooling by the heat transfer medium and also an electric heating element for heating, whereby the heat transfer medium can be heated when necessary to control the temperature of the electrochemical cell.

[0056] The delivery device 13 depends on the heat transfer medium used. For the preferred fluids used, the delivery device 13 is, for example, a pump. The delivery device 13 is sized to allow a sufficient amount of heat transfer medium to pass through the heat transfer member to control the temperature of the electrochemical cell.

[0057] In addition to the embodiment shown in FIG. 1 with a closed fluid circuit for the heat transfer medium, it is also possible to provide an open circuit. Such an open circuit is preferably used when the heat transfer medium is air. In this case, the ambient air is fed into the housing 3 through the inlet 5 and discharged from the housing through the outlet 7. In contrast to the embodiment shown here, the air is blown out to the surroundings from the outlet. To feed the air through the electrochemical energy storage device, a delivery device 13, in particular a blower, is connected to the inlet 5 and / or to the outlet 7. For the purpose of additional heating, it is possible to provide a heating device 11 at the inlet, heating the air sucked in by the blower. Alternatively, it is possible to arrange the heater in the distributor or in the heat transfer element through which the air flows. It is also possible to arrange the heating device between the electrochemical cell and the heat transfer element.

[0058] 2 and 3 are a cross-sectional view and a plan view of an electrochemical energy storage device, respectively, having a heat transfer member through which heat is transferred by thermal conduction.

[0059] The electrochemical energy storage device 1 comprises a battery pack 41 consisting of a number of single electrochemical cells 15. The electrochemical cells 15 are arranged in a housing 3 comprising a box 43, preferably having the shape of a rectangular parallelepiped and enclosing a space 19 in which the electrochemical cells 15 are arranged. The box 24 has an opening 45, which is closed by a lid 47. As can be seen in figure 2, the lid 47 preferably comprises a rim 49 that extends downwards and surrounds the upper part of the box 43. The size of the lid 47 is such that a first duct is formed between the box 43 and the lid 47.

[0060] Besides the battery pack 41, the box 43 comprises a second duct 23 below the electrochemical cells 15 and heat transfer members 17 arranged between the electrochemical cells 15. The spaces 19 not filled with the electrochemical cells 15 and the heat transfer members 17 are preferably filled with a solid or liquid medium, in particular a solid particulate medium, for example sand such as vermiculite or quartz sand. In particular the liquid or solid medium is used to reduce the influence of the surroundings in case of a fault, such as a breakage of a single electrochemical cell 15, abnormal heating or leakage of active material.

[0061] To connect the electrochemical cells 15 to form the battery pack 41, each electrochemical cell has a negative terminal 51 that protrudes from the center of the upper end of the electrochemical cell 15 when attached to the housing 3, and a positive terminal 53 that protrudes from the periphery of the electrochemical cell 15. In the battery pack 41, one positive terminal 53 and one negative terminal 51 arranged adjacent to each other are electrically connected by a connection terminal 55, thereby forming a string in which a plurality of electrochemical cells 15 are connected in series. A part of the connection terminal 55 is shown in FIG. 3. In the battery pack 41, a plurality of strings are connected in parallel to form a block, and a plurality of blocks are connected in series.

[0062] The box 43 is placed and fixed on a base 57 that supports the box 43 facing downward. The box 43 is preferably composed of an outer metal plate 59 facing outward, an inner metal plate 61 facing inward, and a heat insulating material 63 having electrical insulation properties filled between the outer plate 59 and the inner plate 61.

[0063] The lid 47 is preferably removably attached to the box 43, placed on the box 43 when the electrochemical energy storage device 1 is in use, and removed from the box 43 when the battery pack 41 is inserted or removed.

[0064] The lid 3 is preferably constructed of an outer metal plate 65 facing outward, an inner metal plate 67 facing inward, and a heat insulating material 69 filled between the outer plate 65 and the inner plate 67.

[0065] Preferably, the heat insulating materials 63, 69 are used in the atmospheric environment, and the box 43 and the lid 47 have an atmospheric heat insulating structure. More preferably, the outer plate 59 and the inner plate 61 are provided in a shape and arrangement such that they do not come into contact with each other via the heat insulating material 63, and the outer plate 65 and the inner plate 67 are also provided in a shape and arrangement such that they do not come into contact with each other via the heat insulating material 69. For example, a configuration is adopted in which a space is provided between the outer plate 59 and the inner plate 61, and between the outer plate 65 and the inner plate 67, thereby ensuring electrical insulation in addition to heat insulation.

[0066] By configuring the box 43 and the lid 57 as described above, a gap 71 is formed between the outer plate 59 and the inner plate 61, and a gap 73 is formed between the outer plate 65 and the inner plate 67. When air is present inside the box 43 and the lid 47 and is heated and expands during use, the air flows out to the outside through the gaps 71, 73. As a result, deformation of the box 43 and the lid 47 due to thermal expansion of the air is suppressed.

[0067] Alternatively, the box 43 and / or the lid 47 may have a vacuum insulation structure by employing vacuum insulation panels as the insulation materials 63, 69. In this case, the inner panels 61, 67 and the outer panels 59, 65 are firmly connected.

[0068] In order to form the first duct 21 between the box 43 and the lid 47, a heat insulating cushioning material 75 is preferably disposed at the open end portion of the box 43 where the gap 71 is formed. The first duct 21 is formed on the cushioning material 75 and extends between the outer plate 59 of the box 43 and the inner plate 67 of the lid 47.

[0069] The first and second ducts 21, 23 are respectively provided with a first fan 77 and a second fan 79, which may be electric intake fans. The first fan 77 and the second fan 79 are provided to supply outside air to the first duct 21 and the second duct 23, respectively. The operation of the first and second fans 77, 79 may be controlled by a fan control unit.

[0070] In addition, side heaters 81 may be provided on the surfaces of the inner plates 61 on both sides of the box 43. Furthermore, a bottom heater 83 may be provided on the upper surface 85 of the second duct 23.

[0071] The upper surface of the bottom heater 83 is horizontal, and the battery pack 41 is disposed on the upper surface of the bottom heater 83. More specifically, a plate- or sheet-shaped insulator 87 such as mica is interposed between the bottom heater 83 and the battery pack 41, thereby ensuring insulation between the bottom heater 83 and the battery pack 41.

[0072] The side heater 81 and the bottom heater 83 are preferably electric heaters for heating the inside of the box 43. Typically, the side heater 81 and the bottom heater 83 are used to maintain the inside of the box 43 at an operating temperature so as to maintain the active material of each electrochemical cell 15 of the battery pack 41 in a molten state when the electrochemical energy storage device 1 is in a standby state in which the battery pack 41 is not charged or discharged. The operation of the side heater 81 and the bottom heater 83 is controlled by a heater control unit.

[0073] A rod-shaped heat transfer member 17 is provided to dissipate heat generated in the single electrochemical cell 15 during operation to the outside of the space 19. The embodiment shown in Figures 2 and 3 has a heat transfer member for transferring heat by thermal conduction, and the heat transfer member 17 is made of a material having high thermal conductivity, typically a metal having high thermal conductivity. Preferably, aluminum is used as the material of the heat transfer member 17. However, aluminum, steel, copper or some alloys of these metals may also be used.

[0074] As can be seen from Fig. 3, the electrochemical cells 15 are circular in plan view. If the heat transfer member operates by thermal conduction of the material of the heat transfer member, it is further preferred that each electrochemical cell 15 is in contact with an adjacent electrochemical cell 15. The electrochemical cells are preferably arranged in a rectangular grid, and the heat transfer member 17 is disposed in a space surrounded by four electrochemical cells 15. Since adjacent electrochemical cells 15 are in contact with each other, the center-to-center distance between two adjacent electrochemical cells 15 corresponds to the diameter of one electrochemical cell 15. The heat transfer member is disposed at the intersection of the diagonals of the rectangular grid.

[0075] The heat transfer members 17 also preferably have a circular cross-sectional area and are positioned in the space surrounded by the electrochemical cells 15 such that the longitudinal axes of the electrochemical cells 15 and the heat transfer member 17 extend parallel and such that the heat transfer members 17 are in contact with all of the electrochemical cells 15 surrounding each heat transfer member 17.

[0076] However, when the heat transfer member is designed as shown in FIG. 3, the heat transfer member 15 is in line contact with the surrounding electrochemical cells 15 (point contact in the cross-sectional view shown in FIG. 3). From the viewpoint of improving heat transfer performance, the cross-sectional shape perpendicular to the longitudinal direction of the heat transfer member 17 may be determined so that the heat transfer member 17 and the electrochemical cells 15 are in surface contact. For example, all or most of the space between the electrochemical cells 15 may be the region in which the heat transfer member 17 is disposed, and the heat transfer member 17 has a cross-sectional shape corresponding to the cross-sectional shape of this region. In such a case, the side surface of the heat transfer member 17 comes into contact with the side surface of the electrochemical cells 15 widely, and high heat transfer performance is obtained.

[0077] It is further possible that the heat transfer member 17 and the electrochemical cell 15 are not in contact if adequate heat transfer can be obtained otherwise. In this case, heat is transferred from the electrochemical cell 15 to the heat transfer member 17 by heat transfer via a medium in the space between the electrochemical cell 15 and the heat transfer member 17.

[0078] In addition to having a circular cross section, the heat transfer member 17 may have other shapes, such as a rectangular prism, a triangular prism, or a shape having irregularities on the side along the length to increase the surface area, so long as it can be placed in the space between the electrochemical cells 15. Furthermore, it is also possible to place multiple heat transfer members 17 in each space between the electrochemical cells 15.

[0079] The heat transfer member 17 may be in the shape of a hollow pipe or a solid rod as long as good heat transfer performance is ensured. The shape of a hollow pipe is advantageous not only in terms of cost but also in that sand can be filled inside. More specifically, in order to reduce the inside of the box 43 equipped with a certain amount of electrochemical cells 15, it is necessary to fill the inside of the box 43 with a predetermined amount of sand. The type of sand filled in the space 19 may be the same as the type of sand filled in the pipe-shaped heat transfer member 17, or may be different. Furthermore, in one electrochemical energy storage device 1, the pipe-shaped heat transfer member 17 and the rod-shaped heat transfer member 17 may coexist.

[0080] When the heat transfer member 17 has a pipe shape, both ends of the heat transfer member 17 may be independently closed or open, or both ends may be independently provided with detachable covers.

[0081] 3, the heat transfer member 17 may be disposed only in the spaces between the electrochemical cells 15 near the center of the battery pack 41, and the heat transfer member 17 may be omitted in the spaces between the electrochemical cells 15 near the wall of the box 43. This is possible because heat is more easily released to the outside near the wall of the box 43 than near the center of the box 43.

[0082] 2, a lower end 89 of each heat transfer member 17 is in contact with the insulator 87. Meanwhile, an upper end 91 of the heat transfer member 17 is arranged so as to at least partially protrude into the first duct 21. Preferably, the upper end 91 of the heat transfer member 17 is arranged so as to be close to the inner plate 67 of the lid 47 forming the upper surface of the first duct 21, in particular so as to be in contact with the upper surface of the first duct 21.

[0083] To control the electrochemical cell, it is preferable to provide a controller that controls the operation of each part. The controller can be configured with a general-purpose or dedicated computer having a CPU, ROM, RAM, etc., and functions as a controller by executing an operation program stored in a predetermined storage medium built into the computer or externally connected thereto. The controller mainly includes a battery operation control unit and a temperature control unit as virtual components realized by executing the operation program.

[0084] The battery operation control unit controls the charging and discharging operations of the electrochemical energy storage device 1 in the battery pack 41, the power supplying operations and the power receiving operations between the electrochemical energy storage device 1 and the outside, and the like.

[0085] The temperature control unit controls the temperature (particularly the temperature of the space 19) inside the electrochemical energy storage device 1 during operation (charging / discharging) and standby of the electrochemical energy storage device 1 based on an output signal (temperature signal) from a temperature sensor provided at a predetermined position of the box 43. The temperature control unit includes a fan control unit that controls the operation of the first fan 77 and the second fan 79, and a heater control unit that controls the operation of the side heater 81 and the bottom heater 83.

[0086] During operation of the electrochemical energy storage device 1, charging / discharging operations in the battery pack 41, and power supplying and receiving operations between the battery pack 41 and the outside are performed under the control of the battery operation control unit, and at this time, the fan control unit appropriately operates the first fan 77 and the second fan 79 to blow low-temperature air from the outside into the first duct 21 and the second duct 23 to maintain the operating temperature inside the electrochemical energy storage device 1. In this way, charging / discharging operations and power supplying / receiving operations are performed while the operating temperature is maintained.

[0087] On the other hand, during standby, the electrochemical energy storage device is maintained at an operating temperature mainly by turning on / off the electrical current to the side heater 81 and the bottom heater 83 based on the output signal from the temperature sensor by the heater control unit.

[0088] During operation, heat of reaction is generated in each electrochemical cell 15. The heat of reaction is transferred to the surroundings of each electrochemical cell 15 and then transferred to the heat transfer member 17, which has a higher thermal conductivity than the medium filling the space 19. The heat transferred from the electrochemical cells 15 to the heat transfer member 17 is indicated by arrows 93 in FIG. 2.

[0089] As indicated by arrows 95 , 97 , heat transferred to the heat transfer member 17 travels rapidly to the upper end 91 and lower end 89 of the heat transfer member 17 .

[0090] During operation of the electrochemical energy storage device, by operating the first fan 77, outside air 99 having a lower temperature than the temperature inside the box 43 is introduced into the first duct 21. The air flows through the first duct 21 as shown by the arrow 101. The air flowing through the first duct 21 absorbs the heat generated by the electrochemical cells 15 by cooling the lower surface of the first duct 21. Furthermore, the upper end 91 of the heat transfer member 17 is cooled by the air flowing through the first duct 21. The air thus heated is discharged to the surroundings as shown by the arrow 103.

[0091] If a second fan 79 is also present, it is operated during operation of the electrochemical energy storage device 1 and introduces outside air 105 into the second channel 23. The air flows through the second channel 23 as indicated by arrow 107, thereby cooling the upper surface of the second duct 23 and thus the space 19 containing the battery pack 41 and the lower end 89 of the heat transfer member 17. Heat transfer from the space 19 to the air flowing through the second duct 23 is possible even if an insulator 87 and a bottom heater 83 are provided between the electrochemical cells 15 and the heat transfer member 17, which are not operational during normal operation of the electrochemical energy storage device 1, due to the high temperature difference between the electrochemical cells 15 and the outside air during operation.

[0092] In order to further improve the heat transfer from the heat transfer element 17 to the air flowing through the second duct 23, it is also possible to design the heat transfer element 17 so that its lower end 89 protrudes into the second duct 21.

[0093] A further advantage of the heat transfer member 17 is that even when the electrochemical energy storage device 1 is on standby, when the battery pack 41 is heated by the side heater 81 and the bottom heater 83, heat from the bottom heater 83 is transferred to the electrochemical cell 15 by heat transfer via the heat transfer member 17, thereby maintaining the temperature of the electrochemical cell 15 more efficiently.

[0094] According to the invention, at least one heat transfer element protrudes into the first duct. Further heat transfer elements can be arranged as shown in figures 4 to 6.

[0095] The arrangement shown in Figure 4 corresponds to the arrangement in Figure 2, in which all heat transfer members 17 protrude into the first duct 21 and are cooled by air flowing around the upper ends 91 of the heat transfer members 17 protruding into the first duct 21, thereby ensuring heat dissipation during operation.

[0096] However, even if at least one of the heat transfer members 17 does not protrude into the first duct 21, sufficient heat dissipation by the heat transfer member 17 can be realized. As shown in FIG. 5, the heat transfer member can have a length such that the upper end of the heat transfer member 17 contacts the lower surface of the first duct 21. In this embodiment, no through hole is required on the lower surface of the first duct 21 to guide the heat transfer member 17. In this embodiment, heat is transferred from the upper end of the heat transfer member 17 to the lower surface of the first duct 21, and from the lower surface of the first duct 21 to the air flowing through the first duct.

[0097] It may even be sufficient if the upper end of at least one heat transfer member 17 ends at a distance d below the lower surface of the first duct 21, as shown in Fig. 6. In this case, the heat is transferred to the lower surface of the first duct 21 by a medium between the upper end of the heat transfer member 17 and the lower surface of the first duct 21, and then from the lower surface of the first duct 21 to the air flowing through the first duct 21. If the heat transfer member 17 has a length as shown in Figs. 55 and 6, it is also possible to manufacture the upper duct 21 without providing a through hole for the heat transfer member 17.

[0098] For example, considering that the temperature near the center of the electrochemical energy storage device 1 tends to be higher than the temperature at the outer periphery, the heat transfer member 17 near the center of the electrochemical energy storage device may protrude into the first duct 21, but may not protrude into the first duct 21 at the outer periphery.

[0099] Alternatively or additionally, it is also possible to provide a solid heat transfer member 17 near the center of the electrochemical energy storage device 1 and a pipe-shaped heat transfer member 17 at the outer periphery, and / or to provide a heat transfer member 17 having a larger cross-sectional area near the center of the electrochemical energy storage device and a smaller cross-sectional area when located at the outer periphery.

[0100] In this way, by selectively using heat transfer members 17 having different cooling capacities depending on the location depending on the required cooling performance, the temperature distribution throughout the electrochemical energy storage device 1 can be made uniform.

[0101] When the heat transfer member 17 penetrates the first duct 21, at least one heat dissipation fin may be attached to a portion of the heat transfer member 17 that protrudes into the first duct 21. In this case, heat dissipation from the heat transfer member 17 in the first duct 21 is further promoted.

[0102] The heat transfer member 17 used in the electrochemical energy storage device can have any suitable cross-sectional shape, examples of possible shapes are shown in Figures 7 to 9.

[0103] FIG. 7 is a top view of an electrochemical cell and a heat transfer member of an electrochemical energy storage device, where the heat transfer member is a plate.

[0104] When the heat transfer member 17 is in the form of a plate as shown in FIG. 7, the electrochemical cells 15 are arranged in rows and the heat transfer member 17 is disposed between the rows of electrochemical cells 15 .

[0105] 8 and 9 show an embodiment in which the heat transfer member 17 is a pipe or a rod. To achieve sufficient heat transfer from the electrochemical cells 15 to the heat transfer member 17, the electrochemical cells 15 are arranged around the heat transfer member 17. In addition to arranging four electrochemical cells 15 around one heat transfer member 17, any other number of electrochemical cells 15 around one heat transfer member 17 is also possible, for example 3, 5, 6 or 8 electrochemical cells 15. The number of electrochemical cells 15 arranged around one heat transfer member 17 depends, inter alia, on the diameters of the heat transfer member 17 and the electrochemical cells 15. The larger the diameter of the electrochemical cells 15 and the smaller the diameter of the heat transfer member 17, the fewer the number of electrochemical cells 15 that can be arranged around the heat transfer member 17 without creating too large a space for satisfactory heat transfer.

[0106] The embodiments shown in Figures 8 and 9 differ in the cross-sectional shape of the heat transfer member 17. In the embodiment shown in Figure 8, the heat transfer member 17 has a circular cross-sectional shape, and in the embodiment shown in Figure 9, the heat transfer member 17 has a square cross-sectional shape.

[0107] 8 and 9, the heat transfer member 17 may have other shapes, for example an oval or a polygon with any number of sides, but particularly preferably the heat transfer member 17 has a circular cross-sectional shape as shown in FIG.

[0108] If the heat transfer members 17 are pipes, it is possible to use pipes with different cross-sectional shapes and / or different diameters in one electrochemical energy storage device. However, it is particularly preferred that all heat transfer members 17 have the same shape. Different diameters may be preferred if the amount of heat that needs to be dissipated by the heat transfer members or that needs to be supplied by the heat transfer members is different at different locations in the electrochemical energy storage device 1. In this case, a larger diameter is preferred in areas of the electrochemical energy storage device where a larger amount of heat is generated, in order to remove a larger amount of heat. Thus, a larger diameter is preferred in areas where a larger amount of heat is required, in order to supply a larger amount of heat.

[0109] In the embodiment shown above, the electrochemical cells 15 are arranged adjacent to each other in a rectangular grid, however, the arrangement of the electrochemical cells 15 is not limited thereto.

[0110] For example, the electrochemical cells can be arranged in close packing, as shown in a plan view in Fig. 10. In this case, electrochemical cells having a circular cross-sectional shape are arranged in an equilateral triangular lattice. The heat transfer member 17 is arranged so as to contact three electrochemical cells 15.

[0111] However, in addition to the rectangular and triangular grids shown, the electrochemical cells may be arranged in other grid configurations. example A simulation experiment was conducted to evaluate the effect of the presence or absence of a heat transfer member 17 that transfers heat by thermal conduction of a solid material, and the positional relationship between the heat transfer member 17 and the first duct 21, on the temperature characteristics during discharge of the electrochemical energy storage element.

[0112] In the case of Examples 1 to 3, 25 single electrochemical cells 15 having a diameter of about 100 mm and a length of 500 mm were arranged adjacent to each other in a 5×5 grid in the storage space 19 of a box 43 closed by a lid 47 made of stainless steel (SUH409L, thermal conductivity 27 W / m*K), as shown in FIG. 2 and FIG. 3. A hollow pipe-shaped heat transfer member 17 having an outer radius of 38 mm and an inner radius of 32 mm was arranged in 16 spaces thus formed. The remaining storage space 19 was filled with sand. In Examples 1 to 3, only the arrangement of the heat transfer member 17 was different from each other. It should be noted that each electrochemical cell 15 was capable of continuous discharge for 4 hours at an output of 280 W / DC.

[0113] In the first embodiment, as shown in FIG. 4, the heat transfer member 17 enters the first duct 21, and the upper end portion 91 is in contact with the upper surface of the first duct 21.

[0114] In the second embodiment, the heat transfer member 15 does not pass through the first duct 21, and the upper end 91 of the heat transfer member 17 contacts the lower surface of the first duct 21 as shown in FIG.

[0115] According to the third embodiment, as shown in FIG. 6, the upper end 91 of the heat transfer member 17 is spaced from the lower surface of the first duct 21 by a distance d=5 mm.

[0116] For comparison, an electrochemical energy storage device was used in which the electrochemical cell was arranged similarly to Examples 1 to 3, but did not include a heat transfer member.

[0117] For these examples and comparative examples, a simulation was performed on the temperature distribution at three different height positions of the electrochemical cell 15, namely, the "upper portion", "middle portion", and "lower portion", when discharging was performed at a target temperature of 305° C. The "upper portion", "middle portion", and "lower portion" were set at positions 400 mm, 250 mm, and 20 mm from the bottom surface of the electrochemical cell 15, respectively.

[0118] 11 is a diagram showing temperature distributions in the "upper part," "middle part," and "lower part" of Examples 1 to 3 and Comparative Example obtained by simulation, and the maximum temperature in the temperature distribution. As shown in the lower part of the figure, in each temperature distribution, a battery pack 41 consisting of 25 electrochemical cells 15 is placed in a storage space 19 surrounded by a box 43. However, the heat transfer member 17 is not shown.

[0119] In addition, the darker the color, the higher the temperature in the portion of the battery pack 41 that occupies the center of the accommodation space 19. The white circle indicates the position of the highest temperature.

[0120] From FIG. 11, it can be seen that the temperature tends to be highest approximately at the center and at a certain height position of each electrochemical cell.

[0121] Furthermore, in the comparative example in which the heat transfer member 17 is not provided, the maximum temperature exceeds 400° C. regardless of the height position, whereas in the first to third embodiments in which the heat transfer member 17 is provided, the maximum temperature is suppressed to 340° C. or less. These results show that providing the heat transfer member 17 is effective in dissipating heat during discharge of the electrochemical energy storage device.

[0122] In particular, in Example 1 in which the heat transfer member 17 penetrates into the first duct 21, although the maximum temperature in the "middle part" slightly exceeded 300°C, the temperature was generally below 300°C regardless of the height position, and was below the target temperature of 305°C. Furthermore, the temperature difference within the surface was small. This shows that the configuration of the first embodiment is extremely effective in dissipating heat during discharge of the electrochemical energy storage device.

[0123] On the other hand, in Examples 2 and 3, the maximum temperature was higher than in Example 1, exceeding the target temperature of 305°C, but the temperature difference from the comparative example was significant. In Examples 2 and 3, the temperature of the "bottom" tended to be lower than that of the "top" and "middle", and in the "top" and "middle" parts, the temperature difference between the center and the periphery was relatively significant. From these results, it can be seen that the configurations of Examples 2 and 3 are also somewhat effective in dissipating heat during discharge of the module battery. [Explanation of symbols]

[0124] 1. Electrochemical Energy Storage Devices 3. Housing 5 Inlet for temperature control medium 7 Outlet for temperature control medium 9 Heat exchanger 11 Heating device 13 Delivery device 15 Electrochemical Cell 17 Heat transfer materials 19 Space (filled with a solid or liquid medium) 21 First Duct 23 Second Duct 25 Blinds 27 Inner Pipe 29 Inner Pipe 31 Closed End 33 Gap 35 1st wall 37 Second wall 39 Space 41 Battery Pack 43 boxes 45 Opening 47 Lid 49 Rims 51 Negative terminal 53 Positive terminal 55 Connection terminal 57 Base 59 Outer plate 61 Inner plate 63 Insulation 65 Outer plate 67 Inner plate 69 Insulation 71 Gap 73 Gap 75 Thermal insulation cushioning material 77 No. 1 Fan 79 Second Fan 81 Side heater 83 Bottom Heater 85 Upper surface of second duct 23 87 Insulators 89 Lower end of heat transfer member 17 91 Upper end of heat transfer member 17 93 Heat transferred from a thermoelectrochemical cell to a heat transfer member 95 Heat transferred to the upper end 91 97 Heat transferred to the lower end 89 99 Outside Air 101 Air flow passing through first duct 21 103 Release air to the surroundings 105 Outside Air 107 Air flow through second duct 23

Claims

1. An electrochemical energy storage device comprising a plurality of electrochemical cells (15) in an accommodation space within a housing (3), wherein the electrochemical energy storage device (1) comprises a first duct extending parallel to the upper or bottom part of the housing (3), and one or more heat transfer members (17) disposed in a space (19) between the electrochemical cells (15), and at least one of the heat transfer members (17) protrudes into the first duct (21). An electrochemical energy storage device.

2. The electrochemical energy storage device according to claim 1, wherein the space (19) surrounding the electrochemical cell (15) and the heat transfer member (17) is filled with a liquid or solid material.

3. The electrochemical energy storage device according to claim 2, wherein the solid material is preferably a granular material selected from sand, metal, ceramic or glass.

4. The electrochemical energy storage device according to any one of claims 1 to 3, wherein the heat transfer member (17) is a plate, a solid rod having an arbitrary cross-sectional shape, or a pipe having an arbitrary cross-sectional shape.

5. The heat transfer member (17) is a pipe or rod having an arbitrary cross-sectional shape, and the ratio of the number of the electrochemical cells (15) to the number of the heat transfer members (17) is in the range of 1:4 to 10:

1. The electrochemical energy storage device according to any one of claims 1 to 3.

6. The surface area of the outer heat transfer member (17) disposed near the wall of the housing (3) is smaller than the surface area of the inner heat transfer member (17) disposed at the center of the housing (3). The electrochemical energy storage device according to any one of claims 1 to 3.

7. The ratio of the surface area of the outer heat transfer member (17) to the surface area of the inner heat transfer member (17) is in the range of 0.1 to 1. The electrochemical energy storage device according to any one of claims 1 to 3.

8. The electrochemical energy storage device according to any one of claims 1 to 3, further comprising a second duct disposed at the upper or bottom part of the housing.

9. The electrochemical energy storage device according to claim 8, wherein the electrochemical energy storage device comprises the second duct at the bottom, and a bottom heater is disposed on the second duct. **Claim 10**: The electrochemical energy storage device further comprises a second intake fan capable of supplying air to the second duct from the outside, the second duct including a second intake port through which air is supplied from the second intake fan, a second internal space to which air is supplied from the second intake port, the second internal space being arranged such that the bottom heater is interposed between the second internal space and the arrangement range of the heat transfer member in the accommodation space, and a second exhaust port through which air that has passed through the second internal space is discharged to the outside. The electrochemical energy storage device according to claim 9. **Claim 11** The housing includes a box having heat insulation performance, and the box has an opening closed by a lid having heat insulation performance. The electrochemical energy storage device according to any one of claims 1 to 3. **Claim 12** The first duct is arranged between the box and the lid above the electrochemical cell. The electrochemical energy storage device according to claim 11. **Claim 13** The heat transfer member protruding into the first duct is in contact with the surface of the first duct on the opposite side of the accommodation space in the extending direction of the heat transfer member. The electrochemical energy storage device according to any one of claims 1 to 3. **Claim 14** The electrochemical energy storage device further comprises a first intake fan capable of supplying air to the first duct from the outside, the first duct including a first intake port through which air is supplied from the first intake fan, a first internal space that enables heat to be transferred from the heat transfer member to the air supplied from the first intake port, and a first exhaust port through which air that has passed through the first internal space is discharged to the outside. The electrochemical energy storage device according to any one of claims 1 to 3. **Claim 15**: The heat transfer member is made of one or more metals selected from the group consisting of aluminum, copper, steel, and alloys containing at least one of these metals. The electrochemical energy storage device according to any one of claims 1 to 3. **Claim 16** The electrochemical cells are arranged to form a square lattice in plan view, and the heat transfer members are respectively arranged at the center positions of the unit cells of the square lattice. The electrochemical energy storage device according to any one of claims 1 to 3. **Claim 17** The heat transfer member is in contact with each of the four cells constituting the unit cell among the plurality of cells. The electrochemical energy storage device according to claim 16.

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