Electricity storage module

Abstract

An electricity storage module (10) comprises: at least one electricity storage device (20); a case (40) in which the at least one electricity storage device (20) is housed; a coolant (50) into which the at least one electricity storage device (20) is immersed inside the case (40); and an exhaust mechanism (60) that is disposed inside of the coolant (50) and cools and collects the coolant (50) contained in gas exhausted from the case (40). The exhaust mechanism (60) has: a cooling / collection section (61) that is disposed on the bottom surface of the case (40) and cools and collects the coolant (50) contained in the gas; an inlet pipe (62) that connects the cooling collection section (61) and an upper part inside the case (40); and an outlet pipe (63) that connects the cooling / collection section (61) and the outside of the case (40).

Description

Energy storage module

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

[0002] An electric storage module is used as a power source having a plurality of electric storage devices. The electric storage module may include a plurality of electric storage devices, a case for accommodating the plurality of electric storage devices, and a coolant for immersing the plurality of electric storage devices within 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 is characterized by comprising 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 an exhaust mechanism disposed within the coolant and which cools and collects the coolant contained in gas exhausted from the case.

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

[0007] Fig. 1 is a side cross-sectional view showing an electric storage module as an example of an embodiment; Fig. 2 is a side cross-sectional view showing an electric storage device as an example of an embodiment; Fig. 3 is a schematic view showing an exhaust mechanism as an example of an embodiment; Fig. 4 is a schematic view showing an exhaust mechanism as another example of an embodiment; Fig. 5 is a schematic view showing an exhaust mechanism as another example of an embodiment; Fig. 6 is a schematic view showing an exhaust mechanism as another example of 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. However, 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 energy storage module 10 includes a plurality of (at least one) energy storage devices 20, a case 40 in which the plurality of energy storage devices 20 are housed, a cooling liquid 50 in which the plurality of energy storage devices 20 are immersed inside the case 40, and an exhaust mechanism 60 that is disposed in the cooling liquid 50 and cools and collects the cooling liquid 50 contained in the gas inside the case 40.

[0012] The multiple power storage devices 20 may be packed as densely as possible within the power storage module 10, taking safety into consideration, and may be arranged so that adjacent power storage devices 20 are 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). Alternatively, the multiple power storage devices 20 may be arranged so that the power storage devices 20 closest to the four sides are arranged. Details of the power storage device 20 will be described later. Note that the power storage module of the present disclosure may include only one power storage device 20.

[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 plate 32 is disposed on the upper surface of the upper holder 31. The positive current collector plate 32 is a member that connects positive terminals serving as first electrode terminals of the power storage device 20, which will be described later. The positive current collector plate 32 is immersed in the coolant 50 inside the case 40. The positive current collector plate 32 is formed from a conductive metal plate.

[0015] The lower side of the power storage device 20 is held by a lower holder 33. The lower holder 33 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 33. The negative current collector 34 is a member that 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 of a conductive metal plate. Note that both the positive current collector 32 and the negative current collector 34 may be connected to the power storage device 20 in a state where they are both arranged together at one end of the power storage device 20.

[0017] As described above, the case 40 houses a plurality of power storage devices 20. The case 40 is made of a metal such as aluminum or a resin, and is formed into a substantially rectangular parallelepiped shape. The case 40 can protect the power storage devices 20 housed therein from dust and water.

[0018] As described above, the coolant 50 immerses the plurality of power storage devices 20 inside the case 40. In the power storage module 10, the coolant 50 can cool the power storage devices 20. 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.

[0019] As described above, exhaust mechanism 60 is disposed inside case 40, and cools and collects coolant 50 contained in gas exhausted from case 40 in the event of an abnormality in power storage device 20. Details of exhaust mechanism 60 will be described later.

[0020] [Power Storage Device] The power storage device 20 as an example of an embodiment will be described with reference to FIG.

[0021] In this embodiment, the power storage device 20 is a cylindrical lithium-ion secondary battery, but may also be a nickel-metal hydride battery, a capacitor, or the like. 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 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 is not limited to the cylindrical outer can 25. A rectangular outer can or a pouch-shaped outer casing may also be used.

[0022] 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 sandwich the sealing body 26 in the axial direction via the gasket 29, thereby sealing the opening of the outer can 25.

[0023] 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.

[0024] 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 32 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.

[0025] [Exhaust Mechanism] An exhaust mechanism 60 as an example of an embodiment will be described with reference to Fig. 3. In Fig. 3, for ease of understanding, the top surface of the case 40 is shown open, and the upper holder 31, the positive electrode current collector plate 32, and the coolant 50 are omitted.

[0026] As described above, the exhaust mechanism 60 is disposed inside the case 40, and cools and collects the coolant 50 contained in the gas exhausted from the case 40, for example, when an abnormality occurs in the power storage device 20. As will be described in detail later, the exhaust mechanism 60 can reduce white smoke contained in the gas when the power storage device 20 experiences thermal runaway. Note that the cause of the gas heating does not necessarily have to be an abnormality (temperature rise) in the power storage device 20. The gas heating may also be due to the coolant 50 being heated by some other factor.

[0027] Here, abnormalities in the power storage device 20 include thermal runaway of the power storage device 20. When thermal runaway occurs in the power storage device 20, the power storage device 20 becomes hot, and the coolant 50 vaporizes in a high-temperature, high-pressure environment and is exhausted from the case 40. When thermal runaway occurs in the power storage device 20, the coolant 50 becomes mist-like (atomized liquid) in a high-temperature, high-pressure environment and is exhausted from the case 40.

[0028] In other words, the gas in the case 40 when the storage device 20 experiences thermal runaway includes the coolant 50 that evaporates when the storage device 20 reaches a high temperature under a high-temperature and high-pressure environment, the coolant 50 that turns into a mist (atomized liquid) that resembles white smoke under a high-temperature and high-pressure environment, and other gases.

[0029] As will be described in detail later, the exhaust mechanism 60 can reduce the amount of coolant mist 50 contained in the gas exhausted from the case 40 by collecting the coolant mist 50 contained in the gas when the power storage device 20 experiences thermal runaway. This can reduce white smoke contained in the gas, thereby improving the reliability of the power storage module 10.

[0030] The exhaust mechanism 60 is arranged on the bottom surface of the case 40 and has a cooling collection section 61 that cools and collects the cooling liquid 50 contained in the gas, an inlet pipe 62 that connects the upper part of the interior of the case 40 to the cooling collection section 61, and an outlet pipe 63 that connects the cooling collection section 61 to the outside above the case 40.

[0031] The cooling collection unit 61, which will be described in detail later, cools and liquefies the vaporized coolant 50 contained in the gas during thermal runaway of the power storage device 20, and collects the mist-like coolant 50 contained in the gas. The cooling collection unit 61 is formed as a serpentine pipe on the bottom surface of the case 40.

[0032] Since the cooling collection part 61 is disposed on the bottom surface of the case 40, it is reliably immersed in the coolant 50 even if the liquid level of the coolant 50 drops, for example, during thermal runaway of the power storage device 20. This allows the vaporized coolant 50 passing through the cooling collection part 61 to be cooled and liquefied. Note that when the vaporized coolant 50 is cooled, it may turn into mist-like coolant 50.

[0033] As described above, the cooling collection unit 61 is formed as a serpentine pipe on the bottom surface of the case 40. In the cooling collection unit 61, the cooling liquid mist 50 is made to detour and travel a long distance, thereby increasing the number of times the cooling liquid mist 50 collides with the wall surfaces of the pipe, causing the cooling liquid mist 50 to condense. This allows the cooling liquid mist 50 to be collected in the cooling collection unit 61. Note that the cooling liquid mist 50 contained in the gas also includes cooling of vaporized cooling liquid 50 that has become cooling cooling liquid mist 50.

[0034] As described above, inlet pipe 62 connects the upper end of the interior of case 40 to cooling collector 61. In the event of thermal runaway of power storage device 20, inlet pipe 62 exhausts gas from case 40 to cooling collector 61. A pressure release valve 64 is provided at the upper end of inlet pipe 62.

[0035] The pressure release valve 64 is provided in the inlet pipe 62 and opens when the pressure inside the case 40 is equal to or higher than a set pressure value. The pressure release valve 64 allows gas to be exhausted from the inlet pipe 62 only when high pressure is generated inside the case 40 during thermal runaway of the power storage device 20. The pressure release valve 64 may be, for example, a valve that can exhaust only gas. The pressure release valve 64 may be, for example, a waterproof, breathable membrane.

[0036] As described above, outlet pipe 63 connects cooling collection unit 61 to the outside above case 40. When power storage device 20 experiences thermal runaway, outlet pipe 63 exhausts coolant 50 and other gases collected in cooling collection unit 61 to the outside of case 40.

[0037] Another embodiment of the exhaust mechanism 70 will be described with reference to Fig. 4. Note that in Fig. 4, for ease of understanding, the top surface of the housing of the cooling collector 71 is shown open. In the following, like reference numerals will be used to designate components common to the above-described energy storage module 10, and description thereof will be omitted.

[0038] The exhaust mechanism 70, which will be described in detail later, is disposed on the bottom surface of the case 40 and includes a cooling collector 71 that cools and collects the coolant 50 contained in the gas, an inlet pipe 72 that connects the upper end of the interior of the case 40 to the cooling collector 71, and an outlet pipe 73 that connects the cooling collector 71 to the outside of the case 40. A pressure release valve is provided at the upper end of the inlet pipe 72.

[0039] As will be described in detail later, when thermal runaway occurs in the storage device 20, the cooling and collecting unit 71 cools and liquefies the vaporized coolant 50 contained in the gas, and collects the mist-like coolant 50 contained in the gas.

[0040] Since the cooling collection part 71 is disposed on the bottom surface of the case 40, it is reliably immersed in the cooling liquid 50 even if the liquid level of the cooling liquid 50 drops, for example, during thermal runaway of the power storage device 20. This allows the vaporized cooling liquid 50 passing through the cooling collection part 71 to be cooled and vaporized.

[0041] The cooling collection unit 71 is formed as a plate-shaped housing on the bottom surface of the case 40. A serpentine path is formed inside the housing. In the cooling collection unit 71, the cooling liquid mist 50 is caused to detour and travel a long distance, thereby increasing the number of times the cooling liquid mist 50 collides with wall surfaces and causing the cooling liquid mist 50 to condense. This allows the cooling liquid mist 50 to be collected in the cooling collection unit 71.

[0042] An exhaust mechanism 80, which is another example of an embodiment, will be described using Fig. 5. Note that in Fig. 4, for ease of understanding, the top surface of the housing of the cooling collector 81 is shown open. In the following, like reference numerals will be used to designate components common to the above-described energy storage module 10, and description thereof will be omitted.

[0043] The exhaust mechanism 80, which will be described in detail later, is arranged on the bottom surface of the case 40 and includes a cooling collector 81 that cools and collects the coolant 50 contained in the gas, an inlet pipe 82 that connects the upper end of the interior of the case 40 to the cooling collector 81, and an outlet pipe 83 that connects the cooling collector 81 to the outside of the case 40. A pressure release valve is provided at the upper end of the inlet pipe 82.

[0044] The cooling and collecting section 81, as will be described in detail later, cools and liquefies the vaporized coolant 50 contained in the gas when the storage device 20 experiences thermal runaway, and collects the mist-like coolant 50 contained in the gas.

[0045] Since the cooling collection part 81 is disposed on the bottom surface of the case 40, it is reliably immersed in the cooling liquid 50 even if the liquid level of the cooling liquid 50 drops, for example, during thermal runaway of the power storage device 20. This allows the vaporized cooling liquid 50 passing through the cooling collection part 81 to be cooled and vaporized.

[0046] Furthermore, the cooling collection unit 81 is formed as a plate-shaped housing on the bottom surface of the case 40. A plurality of cylinders 85 (or a plurality of protrusions) are formed inside the housing. In the cooling collection unit 81, the mist of the cooling liquid 50 is caused to collide with the cylinders 85, thereby condensing the mist of the cooling liquid 50. This allows the cooling liquid 50 to be collected in the cooling collection unit 81.

[0047] An exhaust mechanism 90 as another example of the embodiment will be described with reference to Fig. 6. Note that, in the following, the same reference numerals will be used to designate the same members as those in the above-described power storage module 10, and the description thereof will be omitted.

[0048] The exhaust mechanism 90, which will be described in detail later, is arranged on the bottom surface of the case 40 and has a cooling collection section 91 that cools and collects the coolant 50 contained in the gas, an inlet duct 92 that connects the upper end of the interior of the case 40 to the cooling collection section 91, and an outlet duct 93 that connects the cooling collection section 91 to the outside of the case 40. A pressure release valve 94 is provided at the upper end of the inlet duct 92.

[0049] The cooling and collecting unit 91, which will be described in detail later, cools and liquefies the vaporized coolant 50 contained in the gas when the storage device 20 experiences thermal runaway, and collects the mist-like coolant 50 contained in the gas.

[0050] Since the cooling collection part 91 is adjacent to and below the coolant 50, it is reliably immersed in the coolant 50 even if the liquid level of the coolant 50 drops, for example, during thermal runaway of the power storage device 20. This allows the vaporized coolant 50 passing through the cooling collection part 91 to be cooled and vaporized.

[0051] The cooling collection unit 91 is formed as a meandering duct or a duct with cylinders or protrusions that cause the mist to collide within the flow path. In the cooling collection unit 91, the cooling liquid mist 50 is caused to detour and travel a long distance, thereby increasing the number of times that the cooling liquid mist 50 collides with the wall surfaces of the duct, causing the cooling liquid mist 50 to condense. This allows the cooling liquid mist 50 to be collected in the cooling collection unit 91.

[0052] Summary The present disclosure is further described by the following embodiments.

[0053] 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 that immerses the at least one energy storage device within the case; and an exhaust mechanism that is disposed within the coolant and cools and collects the coolant contained in gas exhausted from the case.

[0054] Configuration 2: The energy storage module according to Configuration 1, wherein the exhaust mechanism includes a cooling and collecting unit disposed on the bottom surface of the case, which cools and collects the coolant contained in the gas, an inlet pipe connecting an upper portion of the case with the cooling and collecting unit, and an outlet pipe connecting the cooling and collecting unit with the outside of the case.

[0055] Configuration 3: The electric storage module according to configuration 2, wherein the cooling collector is formed as a serpentine pipe.

[0056] Configuration 4: The energy storage module according to Configuration 2, wherein the cooling collector is formed as a plate-shaped housing, and a meandering path is formed within the housing.

[0057] Configuration 5: The energy storage module according to Configuration 2, wherein the cooling collector is formed as a plate-shaped housing, and a plurality of pillars or protrusions are provided inside the housing.

[0058] Configuration 6: The energy storage module according to any one of configurations 2 to 5, wherein the inlet pipe is provided with a pressure relief valve that vents air when the pressure in the case is equal to or greater than a predetermined pressure.

[0059] Configuration 7: The energy storage module according to configuration 1, wherein the exhaust mechanism includes a cooling and collecting unit disposed on the bottom surface of the case, which cools and collects the coolant contained in the gas, an inlet duct connecting an upper portion of the case with the cooling and collecting unit, and an outlet duct connecting the cooling and collecting unit with the outside of the case, and the cooling and collecting unit is formed as a serpentine duct.

[0060] Configuration 8: The energy storage module according to Configuration 1, wherein the exhaust mechanism includes a cooling and collecting unit disposed on the bottom surface of the case, which cools and collects the coolant contained in the gas, an inlet duct connecting an upper portion of the case with the cooling and collecting unit, and an outlet duct connecting the cooling and collecting unit with the outside of the case, and the cooling and collecting unit is formed as a duct provided with a plurality of pillars or protrusions.

[0061] 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.

[0062] 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 Positive electrode current collector plate 33 Lower holder 34 Negative electrode current collector plate 40 Case 50 Coolant 60 Exhaust mechanism 61 Cooling collection section 62 Inlet pipe 63 Outlet pipe 64 Pressure release valve 70 Exhaust mechanism 71 Cooling collection section 72 Inlet pipe 73 Outlet pipe 80 Exhaust mechanism 81 Cooling collection section 82 Inlet pipe 83 Outlet pipe 85 Cylinder 90 Exhaust mechanism 91 Cooling collection section 92 Inlet duct 93 Outlet duct 94 Pressure relief valve

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 an exhaust mechanism that is disposed within the coolant and cools and collects the coolant contained in gas exhausted from the case.

2. An energy storage module according to claim 1, wherein the exhaust mechanism comprises: a cooling and collecting section disposed on the bottom surface of the case for cooling and collecting the cooling liquid contained in the gas; an inlet pipe connecting the upper part of the case to the cooling and collecting section; and an outlet pipe connecting the cooling and collecting section to the outside of the case.

3. The electric storage module according to claim 2, wherein the cooling collector is formed as a serpentine pipe.

4. An electric storage module according to claim 2, wherein the cooling collector is formed as a plate-shaped housing, and a meandering path is formed within the housing.

5. An electric storage module according to claim 2, wherein the cooling collector is formed as a plate-shaped housing, and a plurality of pillars or protrusions are provided inside the housing.

6. An electricity storage module according to any one of claims 2 to 5, wherein the inlet pipe is provided with a pressure release valve that releases air when the pressure in the case is equal to or greater than a predetermined pressure.

7. An energy storage module according to claim 1, wherein the exhaust mechanism comprises: a cooling and collecting section disposed on the bottom surface of the case for cooling and collecting the cooling liquid contained in the gas; an inlet duct connecting the upper part of the case with the cooling and collecting section; and an outlet duct connecting the cooling and collecting section with the outside of the case, wherein the cooling and collecting section is formed as a serpentine duct.

8. An energy storage module according to claim 1, wherein the exhaust mechanism comprises: a cooling and collecting section disposed on the bottom surface of the case for cooling and collecting the cooling liquid contained in the gas; an inlet duct connecting the upper part of the case with the cooling and collecting section; and an outlet duct connecting the cooling and collecting section with the outside of the case; and the cooling and collecting section is formed as a duct provided with a plurality of pillars or protrusions.

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