Power storage module

Abstract

The present invention is provided with: a case (40) in which at least one power storage device (20) is accommodated; a cooling liquid (50) in which at least one power storage device (20) is immersed in the case (40); and a duct (60) for exhausting gas in the case (40) and collecting the cooling liquid (50) contained in the gas. A path (61) of the duct (60) has a curved portion (62) at least in part, and a collecting member (63) that collects the cooling liquid (50) is provided in a region on the outer peripheral side of the curved portion (62) inside the duct (60).

Description

Energy storage module

[0001] The present disclosure relates to an energy storage module.

[0002] The power storage module is used as a power source having at least one power storage device. The power storage module may include at least one power storage device, a case that houses the at least one power storage device, and a coolant that immerses the at least one power storage device in the case (see, for example, Patent Document 1).

[0003] Patent No. 6256439

[0004] There is a demand for further improvements in the reliability of energy storage modules.

[0005] The energy storage module according to the present disclosure comprises at least one energy storage device, a case in which the at least one energy storage device is housed, a coolant in which the at least one energy storage device is immersed within the case, and a duct that exhausts gas within the case and collects the coolant contained in the gas, wherein the path of the duct has at least a curved portion, and a collection member that collects the coolant is provided in the area inside the duct on the outer periphery of the curved portion.

[0006] According to the energy storage module of the present disclosure, reliability can be improved.

[0007] 1 is a side cross-sectional view of an electric storage module according to an embodiment; FIG. 2 is a side cross-sectional view of an electric storage device according to an embodiment; FIG. 3 is a perspective view of a duct according to an embodiment;

[0008] An example of an embodiment of the present disclosure will be described in detail below. In the following description, specific shapes, materials, directions, numerical values, etc. are examples for facilitating understanding of the present disclosure, and can be appropriately changed according to the application, purpose, specifications, etc.

[0009] [Overall Configuration of Energy Storage Module] An energy storage module 10 as an example of an embodiment will be described with reference to FIG.

[0010] The power storage module 10 is mounted on an electric vehicle as a power source for the motor that drives the electric vehicle. Note that the power storage module of the present disclosure is not limited to being mounted on an electric vehicle, and may be used as a power source for motor-driven electric devices such as power tools, power-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. Furthermore, the use of the power storage module of the present disclosure is not limited, and may be used as a power source for various electric devices used indoors and outdoors, such as vacuum cleaners, radios, lighting devices, digital cameras, and video cameras.

[0011] The power storage module 10 includes at least one power storage device 20 (multiple in this embodiment), a case 40 that houses the at least one power storage device 20, a coolant 50 that immerses the at least one power storage device 20 inside the case 40, and a duct 60 that exhausts gas inside the case 40 and collects the coolant 50 contained in the gas. Note that the power storage module of the present disclosure may include only one power storage device 20.

[0012] The multiple power storage devices 20 may be packed as densely as possible within the power storage module 10 while taking safety into consideration, and adjacent power storage devices 20 may be arranged substantially close to each other. For example, the power storage devices 20 may be arranged such that six power storage devices 20 surround one power storage device 20 in a plan view (or arranged in a staggered pattern). Furthermore, the multiple power storage devices 20 may be arranged such that the power storage devices 20 closest to the four sides are arranged. Details of the power storage devices 20 will be described later.

[0013] The upper side of the power storage device 20 is held by an upper holder 31. The upper holder 31 is made of, for example, a thermoplastic resin. Thermoplastic resins are broadly classified into general-purpose plastics and engineering plastics, and examples of such resins include polycarbonate, polyethylene, polypropylene, polyamide, and ABS.

[0014] A positive current collector 33 is disposed on the upper surface of the upper holder 31. The positive current collector 33 connects positive terminals serving as first electrode terminals of the power storage device 20, which will be described later. The positive current collector 33 is immersed in the coolant 50 inside the case 40. The positive current collector 33 is formed from a conductive metal plate.

[0015] The lower side of the power storage device 20 is held by a lower holder 32. The lower holder 32 is made of, for example, a thermoplastic resin. Thermoplastic resins are broadly classified into general-purpose plastics and engineering plastics, and examples of such resins include polycarbonate, polyethylene, polypropylene, polyamide, and ABS.

[0016] A negative current collector 34 is disposed on the lower surface of the lower holder 32. The negative current collector 34 connects negative terminals serving as second electrode terminals of the power storage device 20, which will be described later. The negative current collector 34 is immersed in the coolant 50 inside the case 40. The negative current collector 34 is formed from a conductive metal plate.

[0017] In the electricity storage module of the present disclosure, for example, the positive electrode current collector plate 33 and the negative electrode current collector plate 34 may be arranged together at one end of the electricity storage device 20 .

[0018] As described above, the case 40 houses at least one power storage device 20. The case 40 is made of a metal such as aluminum or resin, and is formed into a substantially rectangular parallelepiped shape. The case 40 can protect the power storage device 20 housed in the case 40 from dust and water. An opening 40A is formed in the top surface of the case 40 to exhaust gas from inside the case 40. The opening 40A communicates with an inlet 61A of a path 61 of a duct 60, the details of which will be described later.

[0019] As described above, at least one power storage device 20 is immersed in the coolant 50 within the case 40. In the power storage module 10, the power storage device 20 can be cooled by the coolant 50. This can improve the reliability of the power storage module 10. The coolant 50 has insulating properties. This can prevent current leakage from one power storage device 20 to another power storage device 20 via the coolant 50. The coolant 50 may be, for example, insulating oil, transformer oil, silicone oil, or a fluorine-based inert liquid such as hydrofluoroether.

[0020] The duct 60 exhausts the gas inside the case 40 and collects the coolant 50 contained in the gas. The duct 60 is provided on the top surface of the case 40. The duct 60 of the present disclosure may also be provided on the side surface of the case 40. Details of the duct 60 will be described later. In the power storage module of the present disclosure, a duct may be provided inside the case as long as it is electrically connected to the space inside the case that houses the power storage device.

[0021] [Power Storage Device] The power storage device 20 as an example of an embodiment will be described with reference to FIG.

[0022] In this embodiment, a cylindrical lithium-ion secondary battery is used as the power storage device 20, but a nickel-metal hydride battery, a capacitor, or the like may also be used. The power storage device 20 includes an electrode group 24, for example, a band-shaped positive electrode 21 and a band-shaped negative electrode 22 wound together with a band-shaped separator 23 interposed therebetween; a cylindrical outer can 25 that houses the electrode group 24 together with an electrolyte; a sealing member 26 that insulates and seals an opening provided at one axial end of the outer can 25; a foil-shaped positive electrode tab 27 that electrically connects the positive electrode 21 to the sealing member 26; and a negative electrode tab 28 that electrically connects the negative electrode 22 to the outer can 25. An insulating gasket 29 may be disposed between the outer periphery of the sealing member 26 and the inner circumferential surface of the opening of the outer can 25. Note that the outer casing of the power storage device of the present disclosure may be a rectangular outer can or a pouch-shaped outer casing.

[0023] An annular groove 25A is formed on the outer peripheral surface of the outer can 25, on the opening side. This groove 25A is formed as an annular protrusion on the inner peripheral surface of the outer can 25. The gasket 29 and sealing body 26 are disposed on this annular protrusion within the outer can 25. Furthermore, the opening end of the outer can 25 is crimped so as to bend toward the inside of the outer can 25, with the gasket 29 disposed on the inner peripheral side. The crimped opening end and the protrusion axially sandwich the sealing body 26 via the gasket 29, thereby sealing the opening of the outer can 25.

[0024] The sealing body 26 is provided with a current interrupter (CID) or a safety valve that ruptures when the pressure inside the outer can 25 reaches or exceeds the operating pressure. An insulating plate 30 is provided between the electrode group 24 and the bottom surface 25B of the outer can 25 or between the electrode group 24 and the protrusion (groove 25A) to insulate the electrode group 24 from the outer can 25. The positive electrode tab 27 extends through a through-hole formed in the insulating plate 30. The negative electrode tab 28 may extend through a through-hole formed in the insulating plate 30 or may extend around the insulating plate 30.

[0025] In the energy storage device 20, a positive electrode terminal as a first electrode terminal is provided on the top surface of the sealing body 26, and a negative electrode terminal as a second electrode terminal is provided on the bottom surface 25B of the outer can 25. A positive electrode lead of a positive electrode current collector 33 is joined by welding to the top surface of the sealing body 26, which is the positive electrode terminal as the first electrode terminal. A negative electrode lead of a negative electrode current collector 34 is joined by welding to the bottom surface 25B of the outer can 25, which is the negative electrode terminal as the second electrode terminal.

[0026] [Duct] A duct 60 as an example of an embodiment will be described with reference to FIG.

[0027] As described above, the duct 60 exhausts the gas inside the case 40 and collects the coolant 50 contained in the gas. As will be described in detail later, the duct 60 can reduce white smoke contained in the gas exhausted from the case 40.

[0028] Here, when gas including white smoke is exhausted from the case 40 of the power storage module 10, this includes the occurrence of an abnormality in the power storage device 20. The occurrence of an abnormality in the power storage device 20 includes the occurrence of thermal runaway in the power storage device 20. When the power storage device 20 is experiencing thermal runaway, the power storage device 20 reaches a high temperature, and the coolant 50 vaporizes in a high-temperature, high-pressure environment and is exhausted from the case 40. When the power storage device 20 is experiencing thermal runaway, the coolant 50 becomes mist (atomized liquid) in a high-temperature, high-pressure environment and is exhausted from the case 40 as white smoke. In other words, the gas inside the case 40 when the power storage device 20 is experiencing thermal runaway includes the coolant 50 that has vaporized in a high-temperature, high-pressure environment when the power storage device 20 reaches a high temperature, the coolant 50 that has become mist (white smoke) in a high-temperature, high-pressure environment, and other gases.

[0029] As will be described in detail later, duct 60 can collect coolant 50 that has turned into mist (white smoke) contained in the gas exhausted from case 40 during thermal runaway of power storage device 20, thereby reducing the amount of coolant 50 mist contained in the gas. This can reduce the amount of white smoke contained in the gas. As a result, the reliability of power storage module 10 can be improved.

[0030] As an example, the path 61 of the duct 60 is formed in a spiral shape. In other words, the path 61 of the duct 60 has at least a partial curved portion 62. The curved portion 62 of the path 61 allows the gas exhausted from the case 40 to pass through while being bent, as will be described in detail later. This allows the coolant mist 50 contained in the gas to be forced to pass by being attracted to the outer periphery of the curved portion 62 by centrifugal force.

[0031] The spiral diameter, number of spiral turns, and spiral gap of the duct path of the present disclosure are not particularly limited. Furthermore, the duct path of the present disclosure is not limited to the spiral shape described above. The duct path of the present disclosure may have at least a partial curved portion. The duct path of the present disclosure may have a shape that is curved by, for example, one full turn or half a full turn. In the present disclosure, the duct path may extend along a predetermined plane.

[0032] The spiral duct may have a hollow portion extending along the winding axis, and a heat dissipation means may be provided in the hollow portion. By thermally connecting the heat dissipation means to the inner peripheral surface of the duct, the duct can be cooled while preventing the overall size of the duct from increasing. The heat dissipation means may be a heat dissipation fin or a cooling pipe through which a refrigerant flows. The heat dissipation means may also be an inlet pipe for a coolant.

[0033] The path 61 of the duct 60 extends upward from the inlet 61A to the outlet 61B. The inlet 61A is connected to an opening 40A formed at the upper end of the side surface of the case 40. The outlet 61B is connected to the outside. Note that the path of the duct of the present disclosure may extend downward, horizontally, or obliquely.

[0034] A collection member 63 that collects the coolant 50 is provided in the region of the inner space of the duct 60 on the outer periphery of the curved section 62. As will be described in detail below, the collection member 63 can collect the mist of coolant 50 that passes through the curved section 62 and is forced toward the outer periphery by centrifugal force. This can reduce white smoke contained in the gas. As a result, the reliability of the energy storage module 10 can be improved. Note that in the duct of the present disclosure, a collection member may also be provided in the region on the inner periphery of the curved section. Also, a collection member need not be provided in the region on the inner periphery of the curved section.

[0035] The capture member 63 is a mesh-like member made of resin, metal, or ceramic. In a cross-sectional view perpendicular to the path 61 of the duct 60, the capture member 63 is formed along the inside of the duct 60 at an angle of 180° to the outer periphery of the curved portion 62. Note that the capture member of the present disclosure may be formed along the inside of the duct at an angle of 120° or 210° to the outer periphery of the curved portion. For example, in a cross-sectional view perpendicular to the path of the duct, the capture member may be formed along the inside of the duct at an angle of 120° or 210° to the outer periphery of the curved portion.

[0036] An inlet 61A of the path 61 of the duct 60 is inclined upward. As a result, as will be described in detail later, a portion of the coolant 50 collected in the path 61 is recovered into the case 40 from the inlet 61A. As a result, loss of the coolant 50 contained in the gas can be minimized. This ensures the function of preventing fire from spreading and fire leakage in the power storage device 20 in the power storage module 10.

[0037] As described above, when thermal runaway occurs in the power storage device 20, the gas inside the case 40 is exhausted to the duct 60 and passes through the spiral path 61. At this time, centrifugal force causes the mist of coolant 50 contained in the gas to pass near the outer periphery of the path 61. The coolant 50 that has condensed in the region on the outer periphery of the path 61 is collected by the collection member 63.

[0038] This reduces the amount of white smoke contained in the gas, thereby improving the reliability of the energy storage module 10. Furthermore, by recovering a portion of the coolant 50 contained in the gas, loss of the coolant 50 can be minimized. This ensures the function of preventing fire from spreading and fire leakage in the energy storage device 20 in the energy storage module 10.

[0039] In the duct of the present disclosure, a heat dissipation section may be formed on the outer periphery of the curved section. This heat dissipation section may be roughened to improve heat dissipation performance compared to the remaining section, or a heat dissipation means with a predetermined heat capacity may be thermally connected to the outer periphery of the curved section. When a heat dissipation means is used, the heat dissipation means may be cylindrical so that the duct is housed within its hollow section. This configuration can promote liquefaction of gas flowing through the curved section on the outer periphery.

[0040] [Summary] The present disclosure is further described by the following embodiments. Configuration 1: An energy storage module comprising: at least one energy storage device; a case that houses the at least one energy storage device; a coolant in which the at least one energy storage device is immersed within the case; and a duct that exhausts gas within the case and collects the coolant contained in the gas, wherein the path of the duct has at least a partial curved section, and a collection member that collects the coolant is provided in an area inside the duct that is on the outer periphery of the curved section. Configuration 2: The energy storage module according to Configuration 1, wherein the path of the duct is formed in a spiral shape. Configuration 3: The energy storage module according to Configuration 1 or 2, wherein the path of the duct is formed upward. Configuration 4: The energy storage module according to Configuration 3, wherein an inlet of the duct is inclined upward. Configuration 5: The energy storage module according to configuration 1, wherein a heat dissipation section is provided outside the duct on an outer circumferential side of the curved section. Configuration 6: The energy storage module according to configuration 2, wherein a heat dissipation means is disposed in a hollow portion of the spiral duct, and the heat dissipation means and the duct are thermally connected.

[0041] It should be noted that the present disclosure is not limited to the above-described embodiments and their variations, and it goes without saying that various modifications and improvements are possible within the scope of the matters described in the claims of the present application.

[0042] REFERENCE SIGNS LIST 10 Energy storage module, 20 Energy storage device, 21 Positive electrode, 22 Negative electrode, 23 Separator, 24 Electrode group, 25 Outer can, 25A Groove, 25B Bottom surface, 26 Sealing body, 27 Positive electrode tab, 28 Negative electrode tab, 29 Gasket, 30 Insulating plate, 31 Upper holder, 32 Lower holder, 33 Positive electrode current collector, 34 Negative electrode current collector, 40 Case, 50 Coolant, 60 Duct, 61 Path, 61A Inlet, 61B Outlet, 62 Curved portion, 63 Collection member

Claims

1. An energy storage module comprising: at least one energy storage device; a case that houses the at least one energy storage device; a coolant that immerses the at least one energy storage device within the case; and a duct that exhausts gas within the case and collects the coolant contained in the gas, wherein the path of the duct has at least a curved portion, and a collection member that collects the coolant is provided inside the duct in an area on the outer periphery of the curved portion.

2. The energy storage module according to claim 1, wherein the path of the duct is formed in a spiral shape.

3. The energy storage module according to claim 1 or 2, wherein the path of the duct is formed in an upward direction.

4. The energy storage module according to claim 3, wherein the inlet of the duct is inclined upward.

5. The energy storage module according to claim 1, wherein a heat dissipation section is provided on the outer periphery of the curved section outside the duct.

6. An electricity storage module according to claim 2, wherein a heat dissipation means is disposed in the hollow portion of the spiral duct, and the heat dissipation means and the duct are thermally connected.

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