Power storage module

Abstract

A power storage module (10) comprises: at least one power storage device (20); a case (40) in which the at least one power storage device (20) is housed; a cooling liquid (50) which is within the case (40) and in which the at least one power storage device (20) is immersed; and a duct (60) that exhausts gas within the case (40) and collects the cooling liquid (50) contained in the gas. The path of the duct (60) extends in a spiral shape. A wall (62) of the duct (60) also extends in a spiral shape.

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, and the path of the duct extends in a spiral shape.

[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 electricity storage module as an example of an embodiment; Fig. 2 is a side cross-sectional view showing an electricity storage device as an example of an embodiment; Fig. 3 is a perspective view showing the inside of a duct as an example of an embodiment; Fig. 4 is a schematic cross-sectional view showing a duct in another example of an embodiment; Fig. 5 is a schematic cross-sectional view showing the operation of a duct as an 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. 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. Examples of the thermoplastic resin 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. Examples of the thermoplastic resin 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 at the upper end of the side 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 side surface of the case 40. Note that the duct 60 of the present disclosure may be provided on the top surface of the case 40. The duct of the present disclosure may also be located inside the case 40. Details of the duct 60 will be described later.

[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 strip-shaped positive electrode 21 and a strip-shaped negative electrode 22 wound together with a strip-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 sandwich the sealing body 26 in the axial direction 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 an abnormality in the power storage device 20. An abnormality in the power storage device 20 includes a thermal runaway of the power storage device 20. Note that the coolant 50 may turn into mist not only during thermal runaway or a cell abnormality. During thermal runaway of 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. Furthermore, during thermal runaway of the power storage device 20, the coolant 50 turns into 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 during thermal runaway of the power storage device 20 includes the coolant 50 that has vaporized in a high-temperature, high-pressure environment when the power storage device 20 becomes hot, the coolant 50 has turned into 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] The duct 60 includes a spirally formed passage 61, a spirally formed wall 62, and a side plate 63 that covers one or the other axial end of the spiral passage 61 formed by the wall 62, each of which will be described in detail later. Note that a portion of the other end of the passage 61 formed by the wall 62 may be covered by the side, top, or bottom surface of the case 40.

[0031] As described above, the path 61 is formed in a spiral shape. The inlet 61A of the path 61 (the exhaust inlet of the duct 60) is formed on the outside of the spiral, for example, at the outermost periphery. The outlet 61B of the path 61 (the exhaust outlet of the duct 60) is formed on the inside of the spiral, for example, at the center of the spiral, as an opening in a side plate 63 (described later).

[0032] With the above configuration, gas exhausted from case 40 is exhausted from inlet 61A formed at the outermost periphery of the spiral toward outlet 61B formed in the center. Note that the duct of the present disclosure may be configured so that gas exhausted from case 40 is exhausted from inlet formed at the center of the spiral toward outlet formed at the outermost periphery.

[0033] The path 61 allows the gas exhausted from the case 40 to pass in a spiral shape. This allows the coolant mist 50 contained in the gas to be forced toward the outer periphery by centrifugal force and pass through. As a result, the coolant mist 50 is separated from the gas and can be condensed on the outer periphery of the path 61.

[0034] The inlet 61A may be formed to face downward in the vertical direction. The inlet 61A is connected to an opening 40A formed at the upper end of the side surface of the case 40. 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 through 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. Note that in the power storage module of the present disclosure, a duct may be arranged such that the path of the duct extends in a direction perpendicular to the vertical direction.

[0035] As described above, the wall 62 is formed in a spiral shape. More specifically, the wall 62 is continuously formed so that the radius of curvature gradually decreases from the inlet 61A toward the outlet 61B. A slit 62A that penetrates (is cut out from) the wall 62 in the thickness direction is formed in a portion of the wall 62 that separates the exhaust upstream side and the exhaust downstream side of the passage 61 (a portion that separates two regions of the passage that are sandwiched along the radial direction of the duct 60). In other words, the slit 62A is not formed in the portion of the wall 62 that separates the passage 61 from the outside.

[0036] The slits 62A are formed to connect the exhaust upstream side and the exhaust downstream side of the path 61. The slits 62A are formed perpendicular to the exhaust direction. There are no particular limitations on the number, formation position, opening width, etc. of the slits 62A, but forming the slits 62A prevents a decrease in the strength of the wall 62. From the perspective of collecting the mist, it is preferable that the slits 62A are provided in a region where the wall 62 extends in a curved manner, for example, in order to easily generate centrifugal force on the mist.

[0037] The slit 62A allows the coolant 50 that has condensed on the outer periphery of the path 61 to be returned to the upstream side of the exhaust gas. As a result, the evaporated coolant 50 on the upstream side of the exhaust gas can be cooled and liquefied into mist by the condensed coolant 50 that has been returned to the upstream side of the exhaust gas.

[0038] Furthermore, the condensed cooling liquid 50 returned to the upstream side of the exhaust gas captures the mist-like cooling liquid 50 on the upstream side of the exhaust gas, and the condensed cooling liquid 50 returned to the upstream side of the exhaust gas and the mist-like cooling liquid 50 on the upstream side of the exhaust gas further condense. As a result, the mist-like cooling liquid 50 on the upstream side of the exhaust gas can be collected.

[0039] As described above, the side plate 63 covers one or the other side of the path 61 formed by the wall 62 in the direction in which the wall 62 stands (the axial direction of the vortex). As described above, the outlet 61B of the path 61 is opened in the center of the side plate 63.

[0040] [Another embodiment (duct)] A duct 70 as another example of the embodiment will be described with reference to FIG.

[0041] The duct 70 has a spirally formed passage 71, a spirally formed wall 72, and a side plate covering one side of the passage 71 formed by the wall 72, each of which will be described in detail later. A slit 72A is formed in a portion of the wall 72 that separates the exhaust upstream side and the exhaust downstream side of the passage 71.

[0042] In the duct 70, the path 71 and the wall 72 may include a straight portion. The slit 72A may be formed in the straight portion of the wall 72. The action and effects of the duct 70 are similar to those of the duct 60 described above, and therefore will not be described here.

[0043] The function of the duct 60 will be described with reference to FIG.

[0044] As described above, when thermal runaway occurs in power storage device 20, gas inside case 40 is exhausted to duct 60 and passes through spiral path 61. At this time, centrifugal force causes coolant mist 50 contained in the gas to pass near the outer periphery of path 61. As a result, coolant mist 50 is separated from the gas and condenses on the outer periphery of path 61.

[0045] The coolant 50 that has condensed on the outer periphery of the path 61 passes through the slit 62A and returns to the upstream side of the exhaust gas. The condensed coolant 50 that has returned to the upstream side of the exhaust gas cools the vaporized coolant 50 on the upstream side of the exhaust gas and liquefies into mist.

[0046] Furthermore, the condensed coolant 50 returned to the upstream side of the exhaust gas captures the mist-like coolant 50 on the upstream side of the exhaust gas, and the condensed coolant 50 returned to the upstream side of the exhaust gas and the mist-like coolant 50 on the upstream side of the exhaust gas further condense. The condensed coolant 50 near the inlet 61A drips into the case 40 by gravity and is collected.

[0047] [Summary] The present disclosure is further described by the following embodiments. Configuration 1: An electricity storage module comprising: at least one electricity storage device; a case that houses the at least one electricity storage device; a coolant that immerses the at least one electricity 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 extends in a spiral shape. Configuration 2: The electricity storage module according to Configuration 1, wherein a wall of the duct extends in a spiral shape. Configuration 3: The electricity storage module according to Configuration 2, wherein a slit is formed in a separation section of the wall that is located between an exhaust upstream region and an exhaust downstream region of the path. Configuration 4: The electricity storage module according to Configuration 3, wherein the slit is formed in a curved, extending portion of the separation section. Configuration 5: The power storage module according to any one of configurations 1 to 3, wherein the exhaust outlet of the duct is provided in an area on the inner periphery of the path.Configuration 6: The power storage module according to any one of configurations 1 to 3, wherein the exhaust inlet of the duct is provided in an area on the outer periphery of the path.Configuration 7: The power storage module according to configuration 6, wherein the exhaust inlet faces downward in the vertical direction.

[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] 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 (exhaust inlet), 61B Outlet (exhaust outlet), 62 Wall, 62A Slit, 63 Side plate, 70 Duct, 71 Path, 72 Wall, 72A Slit?

Claims

1. An electricity storage module comprising: at least one electricity storage device; a case that houses the at least one electricity storage device; a coolant that immerses the at least one electricity 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 extends in a spiral shape.

2. The energy storage module according to claim 1, wherein the wall of the duct extends in a spiral shape.

3. The energy storage module according to claim 2, wherein a slit is formed in the wall in a separating section between the exhaust upstream region and the exhaust downstream region of the path.

4. The energy storage module according to claim 3, wherein the slit is formed in a curved and extended portion of the isolation section.

5. An electric storage module according to any one of claims 1 to 3, wherein the exhaust outlet of the duct is provided in an area on the inner periphery of the path.

6. An electric storage module according to any one of claims 1 to 3, wherein the exhaust inlet of the duct is provided in an area on the outer periphery of the path.

7. The energy storage module according to claim 6, wherein the exhaust inlet faces downward in the vertical direction.

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