Electric power storage module

Abstract

An electric power storage module (10) is provided with: at least one electric power storage device (20); a case (40) in which said at least one electric power storage device (20) is accommodated; a cooling liquid (50) for immersing therein said at least one electric power storage device (20) inside the case (40); and a recovery mechanism (60) for recovering the cooling liquid (50) contained in gas discharged from the case (40). The recovery mechanism (60) has: an exhaust pipe (61) through which gas is discharged; and a filter (62) that is provided to the exhaust pipe (61) and collects the cooling liquid (50) contained in the gas.

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 a recovery mechanism that recovers 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] 1 is a side cross-sectional view showing an example of an electric storage module according to an embodiment; FIG. 2 is a side cross-sectional view showing an example of an electric storage device according to an embodiment; FIG. 3 is a side cross-sectional view showing a recovery mechanism 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. 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 a recovery mechanism 60 that recovers the cooling liquid 50 contained in the gas exhausted from 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 thereof include polyethylene, polypropylene, polyamide, and ABS.

[0014] A positive current collector plate 33 is disposed on the upper surface of the upper holder 31. The positive current collector plate 33 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 33 is immersed in the coolant 50 inside the case 40. The positive current collector plate 33 is formed from a metal plate having electrical conductivity.

[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 polyethylene, polypropylene, polyamide, ABS, etc. are used.

[0016] A negative current collector 34 is disposed on the lower surface of the lower holder 32. 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 in the power storage module of the present disclosure, the positive current collector 33 and the negative current collector 34 may be disposed 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, the recovery mechanism 60 recovers the coolant 50 contained in the gas discharged from the case 40 when an abnormality occurs in the power storage device 20. The recovery mechanism 60 is provided on one end side of the upper side of the case 40. The recovery mechanism 60 will be described in detail 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, 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 power storage device of the present disclosure is not limited to a cylindrical outer can 25, and may be a rectangular outer can or a pouch-shaped outer can.

[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 safety valve activation 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 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.

[0025] [Recovery Mechanism] A recovery mechanism 60 as an example of an embodiment will be described with reference to FIG.

[0026] As described above, the recovery mechanism 60 recovers the coolant 50 contained in the gas exhausted from the case 40. One example of a cause of this gas generation is heat generation in the power storage device 20 during an abnormality. However, heat generation in components other than the power storage device 20 may also be the cause. An abnormality in the power storage device 20 includes thermal runaway of the power storage device 20. As will be described in detail later, the recovery mechanism 60 can reduce white smoke contained in the gas exhausted from the case 40 during thermal runaway of the power storage device 20.

[0027] Here, the gas discharged from the case 40 when the power storage device 20 experiences thermal runaway includes coolant 50 that has evaporated in a high-temperature, high-pressure environment when the power storage device 20 reaches a high temperature, coolant 50 that has turned into a mist (atomized liquid) in a high-temperature, high-pressure environment, and other gases. When coolant 50 in a mist state is discharged from the case 40, it may be discharged in the form of white smoke.

[0028] Although details will be described later, the recovery 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.

[0029] Furthermore, as will be described in detail later, the recovery mechanism 60 can collect the mist-like coolant 50 contained in the gas exhausted from the case 40 during thermal runaway of the power storage device 20, thereby minimizing the loss of the coolant 50 filled inside the case 40. As a result, the power storage module 10 can improve its ability to prevent fire from spreading and fire from leaking from the power storage device 20. This can improve the reliability of the power storage module 10.

[0030] The recovery mechanism 60 has an exhaust pipe 61 that exhausts gas from the case 40 when the power storage device 20 experiences thermal runaway, a filter 62 that is provided in the exhaust pipe 61 and that collects the coolant mist 50 contained in the gas, and a recovery pipe 63 that recovers the coolant 50 collected by the filter 62 into the case 40. The recovery mechanism 60, which will be described in detail later, can recover the coolant mist 50 contained in the gas that is exhausted from the case 40 when the power storage device 20 experiences thermal runaway, and can exhaust other gases to the outside of the case 40.

[0031] The exhaust pipe 61 exhausts gas that is exhausted from the case 40 when thermal runaway occurs in the power storage device 20. The exhaust pipe 61 is provided obliquely upward from one end of the top surface of the case 40. Note that the exhaust pipe 61 may also be provided horizontally from the side surface of the case 40.

[0032] A pressure release valve may be provided between the exhaust pipe 61 and the case 40. The pressure release valve may be any valve that opens when the pressure inside the case 40 is equal to or greater than a set pressure value. The pressure release valve allows gas to be exhausted from the exhaust pipe 61 only when the pressure inside the case 40 becomes high pressure during thermal runaway of the power storage device 20. The pressure release valve may be, for example, a membrane that can exhaust only gas. The pressure release valve may be, for example, a waterproof, breathable membrane.

[0033] Filter 62 is provided in exhaust pipe 61 and collects coolant mist 50 contained in the gas exhausted by exhaust pipe 61. More specifically, filter 62 is provided on the tip side of exhaust pipe 61. Filter 62 also exhausts gas other than coolant mist 50 contained in the gas to the outside. Filter 62 has a rotary collector 64 that can rotate around an axis in the exhaust direction, and a filter case 65 that houses rotary collector 64.

[0034] The rotating collector 64 has a rotating shaft 66 arranged along the exhaust direction, a fan 67 that rotates around the exhaust direction of the gas to collect the mist-like coolant 50 contained in the gas, and a turbine propeller 68 that is provided upstream of the fan 67 in the exhaust direction and rotates integrally with the rotating shaft 66 and fan 67.

[0035] As described above, the rotating shaft 66 is disposed inside the filter case 65 along the exhaust direction. Spherical ball portions 66A are formed on both ends of the rotating shaft 66, and abut against recesses inside the filter case 65. The ball portions 66A can reduce friction when the rotating shaft 66 rotates.

[0036] The fan 67 rotates around the exhaust direction of the gas to collect the mist of cooling liquid 50 contained in the gas. The fan 67 has blades 67A arranged radially from the rotation shaft 66 when viewed from the exhaust direction.

[0037] With the above configuration, gas flows through the filter 62 and collides with the blades 67A of the turbine propeller 68, which will be described in detail later, and the colliding coolant 50 flows along the blades 67A to the outer periphery of the fan 67 due to the centrifugal force of the rotating fan 67, and the coolant 50 that has flowed to the outer periphery of the fan 67 flows down due to gravity along the inner periphery of the filter case 65 toward the recovery pipe 63. In this way, the mist-like coolant 50 contained in the gas can be collected.

[0038] As described above, the turbine propeller 68 is provided upstream of the fan 67 in the exhaust direction and rotates integrally with the rotary shaft 66 and the fan 67. The turbine propeller 68 can rotate integrally with the fan 67 by utilizing the fluid force of the gas. This allows the fan 67 to rotate by the fluid force of the gas. The turbine propeller 68 has turbine blades as a row of rotating blades that receive the flow of gas and rotate.

[0039] The recovery pipe 63 recovers the coolant 50 captured by the filter 62 into the case 40. The recovery pipe 63 connects the lower end of the side peripheral surface of the filter case 65 of the filter 62 to the upper part of one side surface of the case 40. A check valve 69 is provided in the recovery pipe 63.

[0040] Check valve 69 is provided in recovery pipe 63 and prevents flow from case 40 to filter 62. Check valve 69 can prevent gas inside case 40 from being exhausted from case 40 toward filter 62 even if the inside of case 40 becomes highly pressurized during thermal runaway of power storage device 20. This can prevent coolant 50 collected by filter 62 from flowing backward through recovery pipe 63.

[0041] Summary The present disclosure is further described by the following embodiments.

[0042] 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 a recovery mechanism that recovers the coolant contained in gas exhausted from the case.

[0043] Configuration 2: The energy storage module according to configuration 1, wherein the recovery mechanism includes an exhaust pipe that exhausts the gas, and a filter that is provided in the exhaust pipe and that collects the coolant contained in the gas.

[0044] Configuration 3: The electric storage module according to configuration 2, wherein the filter includes a fan that rotates around the exhaust direction of the gas and collects the coolant.

[0045] Configuration 4: The energy storage module according to configuration 3, wherein the filter is provided upstream of the fan in the exhaust direction, and further includes a turbine propeller that rotates integrally with the fan.

[0046] Configuration 5: The electric storage module according to any one of Configurations 2 to 4, wherein the recovery mechanism has a recovery pipe that recovers the coolant captured by the filter into the case.

[0047] Configuration 6: The energy storage module according to Configuration 5, wherein the recovery pipe is provided with a check valve that prevents flow from the case to the filter.

[0048] 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.

[0049] 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 portion 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 plate 34 Negative electrode current collector plate 40 Case 50 Coolant 60 Recovery mechanism 61 Exhaust pipe 62 Filter 63 Recovery pipe 64 Rotating collector 65 Filter case 66 Rotating shaft 66A Ball portion 67 Fan 67A Blade 68 Turbine propeller 69 Check 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 a recovery mechanism that recovers the coolant contained in gas exhausted from the case.

2. An electric storage module according to claim 1, wherein the recovery mechanism comprises: an exhaust pipe for exhausting the gas; and a filter provided in the exhaust pipe for collecting the coolant contained in the gas.

3. An electric storage module according to claim 2, wherein the filter has a fan that rotates around the exhaust direction of the gas and collects the coolant.

4. An energy storage module according to claim 3, wherein the filter further comprises a turbine propeller that is provided upstream of the fan in the exhaust direction and rotates integrally with the fan.

5. An electric storage module according to any one of claims 2 to 4, wherein the recovery mechanism has a recovery pipe that recovers the coolant captured by the filter into the case.

6. An electricity storage module according to claim 5, wherein the recovery pipe is provided with a check valve that prevents flow from the case to the filter.

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