Electric power storage module

Abstract

An electric power storage module (110) comprises: at least one electric power storage device (120); a case (140) in which the at least one electric power storage device (120) is accommodated; an exhaust pipe (160) that exhausts gas in the case (140) from the case (140); and a filter mechanism (170) that is provided to the exhaust pipe (160) and collects a cooling liquid (150) contained in the gas. The filter mechanism (170) has a first filter (171) and a second filter (172), and the pressure loss of the first filter (171) is greater than the pressure loss of the second filter (172).

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 at least one electric storage device. The electric storage module may have at least one electric storage device, a case for accommodating the at least one electric storage device, and a coolant in the case for immersing the at least one electric storage device (see, for example, Patent Document 1).

[0003] Patent No. 61256439

[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, an exhaust section that exhausts gas inside the case from the case, and a filter mechanism provided in the exhaust section and through which the gas passes, wherein the filter mechanism has a first filter and a second filter, and the pressure loss of the first filter is greater than the pressure loss of the second filter.

[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 energy storage module as an example of a first embodiment; FIG. 2 is a side cross-sectional view showing an energy storage device as an example of the first embodiment; FIG. 3 is a schematic view showing a filter mechanism as an example of the first embodiment; FIG. 4 is a schematic view showing the operation of the filter mechanism in an initial stage; FIG. 5 is a schematic view showing the operation of the filter mechanism in a convergence stage; FIG. 6 is a side cross-sectional view showing an energy storage module as an example of a second embodiment; FIG. 7 is a side cross-sectional view showing an energy storage device as an example of the second embodiment; FIG. 8 is a schematic view showing the operation of the filter mechanism in an initial stage; FIG. 9 is a schematic view showing the operation of the filter mechanism in a convergence stage; FIG. 10 is a side cross-sectional view showing an energy storage module as an example of a third embodiment; FIG. 11 is a side cross-sectional view showing an energy storage device as an example of the third embodiment; FIG. 12 is a schematic view showing the filter mechanism as an example of the third embodiment; FIG. 13 is a schematic view showing the operation of the filter mechanism in an initial stage; FIG. 14 is a schematic view showing the operation of the filter mechanism in a convergence stage;

[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 Power Storage Module (First Embodiment)] A power storage module 110 as an example of a first embodiment will be described with reference to FIG.

[0010] The power storage module 110 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 110 includes at least one power storage device 120 (multiple in this embodiment), a case 140 that houses the at least one power storage device 120, a coolant 150 in which the at least one power storage device 120 is immersed within the case 140, an exhaust pipe 160 as an exhaust section that exhausts gas within the case 140 from the case 140, and a filter mechanism 170 that is provided in the exhaust pipe 160 and collects the coolant 150, electrolyte, etc. contained in the gas. Note that the power storage module of the present disclosure may include only one power storage device 120.

[0012] The multiple power storage devices 120 may be packed as densely as possible within the power storage module 110 while taking safety into consideration, and adjacent power storage devices 120 may be arranged in close proximity to each other. For example, the power storage devices 120 may be arranged such that six power storage devices 120 surround one power storage device 120 in a plan view (or arranged in a staggered pattern). Furthermore, the multiple power storage devices 120 may be arranged such that the power storage devices 120 closest to each other are located on all four sides. Details of the power storage devices 120 will be described later.

[0013] The upper side of the power storage device 120 is held by an upper holder 131. The upper holder 131 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 133 is disposed on the upper surface of the upper holder 131. The positive current collector 133 connects positive terminals serving as first electrode terminals of the power storage device 120, which will be described later. Note that the amount of the coolant 150 and the positional relationship between the positive current collector 133 and the coolant 150 are not limited to this. The positive current collector 133 is immersed in the coolant 150 inside the case 140. The positive current collector 133 is formed from a conductive metal plate.

[0015] The lower side of the power storage device 120 is held by a lower holder 132. The lower holder 132 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 134 is disposed on the lower surface of the lower holder 132. The negative current collector 134 connects negative terminals serving as second electrode terminals of the power storage device 120, which will be described later. Note that the amount of coolant 150 and the positional relationship between the negative current collector 134 and the coolant 150 are not limited to the above. The negative current collector 134 is immersed in the coolant 150 within the case 140. The negative current collector 134 is formed from a conductive metal plate.

[0017] In the power storage module of the present disclosure, for example, the positive electrode current collector plate 133 and the negative electrode current collector plate 134 may be arranged together at one end of the power storage device 120 .

[0018] As described above, case 140 houses at least one power storage device 120. Case 140 is made of a metal such as aluminum or resin, and is formed into a substantially rectangular parallelepiped shape. Case 140 can protect power storage device 120 housed therein from dust and water.

[0019] As described above, the coolant 150 immerses at least one power storage device 120 within the case 140. In the power storage module 110, the coolant 150 can cool the power storage device 120. This improves the reliability of the power storage module 110. The coolant 150 has insulating properties. This prevents the power storage device 120 from leaking current to other power storage devices 120 via the coolant 150. The coolant 150 may be, for example, insulating oil, transformer oil, silicone oil, or a fluorine-based inert liquid such as hydrofluoroether. Note that in the power storage module of the present disclosure, the power storage devices do not need to be immersed in the coolant. For example, the coolant may flow through piping arranged around each power storage device, or a bag may be arranged between the power storage devices and the coolant may be contained in the bag. It is sufficient that the coolant is thermally connected to the power storage devices.

[0020] As described above, exhaust pipe 160 serving as an exhaust unit exhausts gas inside case 140 from case 140. Exhaust pipe 160 extends upward from the top surface of case 140. Note that the exhaust unit of the present disclosure may be an opening of case 140.

[0021] As described above, the filter mechanism 170 is provided in the exhaust pipe 160 and collects the coolant 150 contained in the gas. The filter mechanism 170 is provided at the tip of the exhaust pipe 160. Note that the filter mechanism of the present disclosure may be provided midway through the exhaust pipe 160. The filter mechanism may also be provided inside the case 140. Details of the filter mechanism 170 will be described later.

[0022] [Power Storage Device] The power storage device 120 as an example of the first embodiment will be described with reference to FIG.

[0023] In this embodiment, a cylindrical lithium-ion secondary battery is used as the power storage device 120, but a nickel-metal hydride battery, a capacitor, or the like may also be used. The power storage device 120 includes an electrode group 124, for example, a band-shaped positive electrode 121 and a band-shaped negative electrode 122 wound together with a band-shaped separator 123 interposed therebetween; a cylindrical outer can 125 that houses the electrode group 124 together with an electrolyte; a sealing member 126 that insulates and seals an opening provided at one axial end of the outer can 125; a foil-shaped positive electrode tab 127 that electrically connects the positive electrode 121 to the sealing member 126; and a negative electrode tab 128 that electrically connects the negative electrode 122 to the outer can 125. An insulating gasket 129 may be disposed between the outer periphery of the sealing member 126 and the inner circumferential surface of the opening of the outer can 125. The outer casing of the power storage device of the present disclosure may be a rectangular outer can or a pouch-shaped outer casing.

[0024] An annular groove 125A is formed on the outer peripheral surface of the outer can 125, on the opening side. This groove 125A is formed as an annular protrusion on the inner peripheral surface of the outer can 125. The gasket 129 and sealing body 126 are disposed on this annular protrusion within the outer can 125. Furthermore, the opening edge of the outer can 125 is crimped so as to be tilted toward the inside of the outer can 125, with the gasket 129 disposed on the inner peripheral side. The crimped opening edge and the protrusion axially sandwich the sealing body 126 via the gasket 129, thereby sealing the opening of the outer can 125.

[0025] The sealing body 126 is provided with a current interrupter (CID) or a safety valve that ruptures when the pressure inside the outer can 125 reaches or exceeds the activation pressure. An insulating plate 130 is provided between the electrode group 124 and the bottom surface 125B of the outer can 125 or between the electrode group 124 and the protrusion (groove 125A) to insulate the electrode group 124 from the outer can 125. The positive electrode tab 127 extends through a through-hole formed in the insulating plate 130. The negative electrode tab 128 may extend through a through-hole formed in the insulating plate 130 or may extend around the insulating plate 130.

[0026] In the power storage device 120, a positive electrode terminal as a first electrode terminal is provided on the top surface of the sealing body 126, and a negative electrode terminal as a second electrode terminal is provided on the bottom surface 125B of the outer can 125. A positive electrode lead of a positive electrode current collector 133 is joined by welding to the top surface of the sealing body 126, which is the positive electrode terminal as the first electrode terminal. A negative electrode lead of a negative electrode current collector 134 is joined by welding to the bottom surface 125B of the outer can 125, which is the negative electrode terminal as the second electrode terminal.

[0027] The filter mechanism 170 will be described with reference to FIG.

[0028] As described above, the filter mechanism 170 is connected to the exhaust pipe 160 and collects the coolant 150, the electrolyte, etc. contained in the gas. The filter mechanism 170 can reduce white smoke contained in the gas exhausted from the case 140, as will be described in detail later.

[0029] Here, when gas containing white smoke is exhausted from the case 140 in the power storage module 110, this includes the occurrence of an abnormality in the power storage device 120. The occurrence of an abnormality in the power storage device 120 includes the occurrence of thermal runaway in the power storage device 120. When the power storage device 120 experiences thermal runaway, gas is exhausted from within the power storage device 120. This gas may contain the electrolyte solution of the power storage device 120. Furthermore, when the power storage device 120 reaches a high temperature, the coolant 150 vaporizes in a high-temperature, high-pressure environment and is exhausted from within the case 140. Furthermore, when the power storage device 120 experiences thermal runaway, the coolant 150 becomes mist-like (atomized liquid) in a high-temperature, high-pressure environment and is exhausted from within the case 140 as white smoke. In other words, the gas inside case 140 during thermal runaway of power storage device 120 includes high-temperature, high-pressure gas released from power storage device 120, coolant 150 that has evaporated in the high-temperature, high-pressure environment when power storage device 120 reaches a high temperature, coolant 150 that has turned into mist (white smoke) in the high-temperature, high-pressure environment, and other gases. In the following, the collection of gas containing mist of coolant 150 is used as an example, but it goes without saying that other gases can also be collected in a similar manner.

[0030] As will be described in detail later, the filter mechanism 170 can reduce the amount of coolant 150 mist contained in the gas exhausted from the case 140 by capturing the coolant 150 that has turned into mist (white smoke) contained in the gas when the power storage device 120 experiences thermal runaway. This can reduce the amount of white smoke contained in the gas. As a result, the reliability of the power storage module 110 can be improved.

[0031] Here, in the initial stage of thermal runaway of the power storage device 120 (for example, from the start to 5 seconds), the coolant 150 in mist form when the power storage device 120 experiences thermal runaway is rapidly exhausted as high-temperature, high-pressure white smoke together with the high-temperature, high-pressure gas exhausted from the power storage device 120. Then, in the subsequent convergence stage (for example, from 5 seconds to 130 seconds after the start), the coolant 150 that has come into contact with the high-temperature power storage device 120 turns into mist and is gradually exhausted as low-temperature, low-pressure white smoke.

[0032] Therefore, for example, if a filter with a small opening rate (high collection efficiency and large pressure loss) is provided in exhaust pipe 160, the high-temperature, high-pressure mist of coolant 150 that is suddenly generated cannot pass through the filter due to pressure loss in the filter in the early stage of thermal runaway of power storage device 120, and there is a risk of damage to case 140, exhaust pipe 160, or the filter. On the other hand, for example, if a filter with a large opening rate (low collection efficiency and small pressure loss) is provided in exhaust pipe 160, there is a risk that the mist of coolant 150 cannot be sufficiently collected.

[0033] According to the filter mechanism 170, as will be described in detail later, in the initial stage of thermal runaway of the power storage device 120, the internal pressure in the case 140 tends to be higher than a predetermined pressure, and the gas in the power storage module passes through the second filter 172, and the second filter 172, which has a large opening rate (low collection efficiency and small pressure loss), collects high-pressure coolant mist 150. In the subsequent convergence stage, the pressure in the case 140 tends to be lower (lower than the predetermined pressure) than in the initial stage of thermal runaway, and the gas in the power storage module 110 passes through the first filter 171, and the first filter 171, which has a small opening rate (high collection efficiency and large pressure loss), collects low-pressure coolant mist 150. This makes it possible to efficiently collect the coolant mist 150 in accordance with the pressure of the coolant mist 150, which changes depending on the stage of thermal runaway of the power storage device 120. In the energy storage module of the present disclosure, it is not necessary for all of the gas generated in the energy storage module to pass through the corresponding filter at each stage. For example, in the early stage of thermal runaway, some of the gas in the case 140 may pass through the first filter 171.

[0034] The filter mechanism 170 includes a cylindrical first filter 171, a cylindrical second filter 172, and a resettable safety valve 174, each of which will be described in detail below. Note that the first and second filters of the present disclosure do not necessarily have to be cylindrical, as long as they cover at least a portion of the space (chamber) enclosed by each filter and communicate with the space that the air reaches after passing through each filter. The portion of the chamber not enclosed by the filter may be enclosed by a non-porous wall.

[0035] The first filter 171, which will be described in detail later, collects the mist-like coolant 150 that is slowly exhausted as low-temperature, low-pressure white smoke. The first filter 171 is formed in a tubular shape, for example, a cylindrical shape. Note that the first filter 171 of the present disclosure may also be formed in a rectangular tubular shape. A tubular interior 171A of the first filter 171 communicates with the exhaust pipe 160. The first filter 171 is housed in a tubular interior 172A of the second filter 172. The first filter 171 is arranged coaxially with the second filter 172. A resettable safety valve 174, which will be described in detail later, is provided at the upper end of the first filter 171.

[0036] The aperture ratio of the first filter 171 is smaller than that of the second filter 172. In other words, the collection rate of the first filter 171 is higher than that of the second filter 172. As a method for controlling the pressure loss of the first filter 171 or the second filter 172, the first filter 171 may be made thicker than the second filter 172 while keeping the aperture ratios of the filters equal. Furthermore, the heat resistance temperature of the first filter 171 is lower than that of the second filter 172.

[0037] The first filter 171 may be made of a material such as a HEPA filter, a ULPA filter, a glass fiber filter, a polyester filter, an active carbon filter, a ceramic filter, a polypropylene filter, a fiberglass filter, a nylon filter, a metal mesh filter, etc. The first filter 171 may be made of a different material from the second filter 172, or may be made of the same material as the second filter 172 but with a smaller opening ratio than the second filter 172.

[0038] As will be described in detail later, the first filter 171 can capture the mist-like coolant 150 that comes into contact with the high-temperature power storage device 120 during the convergence stage and is slowly discharged as low-temperature, low-pressure white smoke.

[0039] The second filter 172, which will be described in detail later, captures the mist-like coolant 150 that is suddenly exhausted as high-temperature, high-pressure white smoke. The second filter 172 is formed in a tubular shape, for example, a cylindrical shape. Note that the second filter 172 of the present disclosure may also be formed in a rectangular tubular shape. The second filter 172 houses the first filter 171. The second filter 172 is disposed coaxially with the first filter 171. Side plates 175 are provided at the upper and lower ends of the second filter 172, respectively.

[0040] The aperture ratio of the second filter 172 is larger than that of the first filter 171. In other words, the collection efficiency of the second filter 172 is lower than that of the first filter 171. As a method for controlling the pressure loss of the first filter 171 or the second filter 172, the second filter 172 may be made thinner than the first filter 171 while keeping the aperture ratios of the filters equal. In addition, the heat resistance temperature of the second filter 172 is higher than that of the first filter 171.

[0041] The second filter 172 may be made of a material such as a HEPA filter, a ULPA filter, a glass fiber filter, a polyester filter, an active carbon filter, a ceramic filter, a polypropylene filter, a fiberglass filter, a nylon filter, or a metal mesh filter. The second filter 172 may be made of a material different from that of the first filter 171, or may be made of the same material as the first filter 171 but with a larger opening ratio than the first filter 171.

[0042] As will be described in detail later, the second filter 172 can capture the mist-like coolant 150 that is suddenly exhausted as high-temperature, high-pressure white smoke together with the high-temperature, high-pressure gas exhausted from the power storage device 120 in the initial stage described above.

[0043] The resettable safety valve 174 is disposed at the upper end of the cylindrical interior 171A of the first filter 171, and when the pressure in the cylindrical interior 171A of the first filter 171 is equal to or greater than the set pressure, the resettable safety valve 174 connects the cylindrical interior 171A of the first filter 171 with the cylindrical interior 172A of the second filter 172, and when the pressure in the cylindrical interior 171A of the first filter 171 is less than the set pressure, the resettable safety valve 174 is a so-called self-resetting safety valve that opens when the set pressure is reached and closes when the pressure drops below the set pressure. The set pressure is lower than the set pressure (operating pressure) of an exhaust valve provided in the power storage module 110 separately from the resettable safety valve 174, and is set, for example, slightly lower than the set pressure of the exhaust valve. When a large amount of gas is suddenly generated inside the power storage module 110 and the gas cannot be sufficiently exhausted by the filter mechanism 170 alone, the exhaust valve operates (opens) to exhaust the gas inside the power storage module 110 .

[0044] According to the return type safety valve 174, in the initial stage described above, the mist-like coolant 150 that is suddenly discharged as high-temperature, high-pressure white smoke together with the high-temperature, high-pressure gas discharged from the power storage device 120 can pass through the second filter 172 without passing through the first filter 171.

[0045] The operation of the filter mechanism 170 will be described with reference to FIGS.

[0046] 4 , in the initial stage of thermal runaway of the power storage device 120, high-temperature, high-pressure coolant mist 150 is rapidly exhausted together with the gas exhausted from the power storage device 120, and it is difficult for the mist to pass through the first filter 171, which has a large pressure loss. At this time, the pressure inside the cylinder 171A of the first filter 171 exceeds the set pressure, and the reset safety valve 174 opens. The high-temperature, high-pressure coolant mist 150 passes through the second filter 172, which has a small pressure loss, and is collected by the second filter 172.

[0047] 5, in the subsequent convergence stage of thermal runaway of power storage device 120, low-temperature, low-pressure mist-like coolant 150 that has been in contact with high-temperature power storage device 120 is slowly exhausted and can pass through first filter 171, which has a large pressure loss. At this time, low-temperature, low-pressure mist-like coolant 150 is collected by first filter 171. At this time, the pressure inside cylindrical interior 171A of first filter 171 falls below the set pressure, and resettable safety valve 174 closes.

[0048] [Overall Configuration of Power Storage Module (Second Embodiment)] A power storage module 210 as an example of a second embodiment will be described with reference to FIG. 6 .

[0049] The power storage module 210 includes at least one power storage device 220 (multiple in this embodiment), a case 240 that houses the at least one power storage device 220, a coolant 250 in which the at least one power storage device 220 is immersed within the case 240, an exhaust pipe 260 as an exhaust section that exhausts gas within the case 240 from the case 240, and a filter mechanism 270 that is provided in the exhaust pipe 260 and collects the coolant 250, electrolyte, etc. contained in the gas. Note that the power storage module of the present disclosure may include only one power storage device 220.

[0050] The multiple power storage devices 220 may be packed as densely as possible within the power storage module 210 while taking safety into consideration, and adjacent power storage devices 220 may be arranged in close proximity to each other. For example, the power storage devices 220 may be arranged such that six power storage devices 220 surround one power storage device 220 in a plan view (or arranged in a staggered pattern). Furthermore, the multiple power storage devices 220 may be arranged such that the power storage devices 220 closest to each other are located on all four sides. Details of the power storage devices 220 will be described later.

[0051] The upper side of the power storage device 220 is held by an upper holder 231. The upper holder 231 is made of, for example, a thermoplastic resin. Examples of the thermoplastic resin include polycarbonate, polyethylene, polypropylene, polyamide, and ABS.

[0052] A positive current collector 233 is disposed on the upper surface of the upper holder 231. The positive current collector 233 connects positive terminals serving as first electrode terminals of the power storage device 220, which will be described later. The positive current collector 233 is immersed in the coolant 250 inside the case 240. Note that the amount of the coolant 250 or the positional relationship between the positive current collector 233 and the coolant 250 is not limited to this. The positive current collector 233 is formed from a conductive metal plate.

[0053] The lower side of the power storage device 220 is held by a lower holder 232. The lower holder 232 is made of, for example, a thermoplastic resin. Examples of the thermoplastic resin include polycarbonate, polyethylene, polypropylene, polyamide, and ABS.

[0054] A negative current collector 234 is disposed on the lower surface of the lower holder 232. The negative current collector 234 connects negative terminals serving as second electrode terminals of the power storage device 220, which will be described later. The negative current collector 234 is immersed in the coolant 250 inside the case 240. Note that the amount of the coolant 250 or the positional relationship between the negative current collector 234 and the coolant 250 is not limited to this. The negative current collector 234 is formed from a conductive metal plate.

[0055] In the power storage module of the present disclosure, for example, the positive electrode current collector plate 233 and the negative electrode current collector plate 234 may be arranged together at one end of the power storage device 220 .

[0056] As described above, case 240 houses at least one power storage device 220. Case 240 is made of a metal such as aluminum or resin, and is formed into a substantially rectangular parallelepiped shape. Case 240 can protect power storage device 220 housed therein from dust and water.

[0057] As described above, the coolant 250 immerses at least one power storage device 220 within the case 240. In the power storage module 210, the coolant 250 can cool the power storage device 220. This improves the reliability of the power storage module 210. The coolant 250 has insulating properties. This prevents the power storage device 220 from leaking current to other power storage devices 220 via the coolant 250. The coolant 250 may be, for example, insulating oil, transformer oil, silicone oil, or a fluorine-based inert liquid such as hydrofluoroether. Note that in the power storage module of the present disclosure, the power storage devices do not need to be immersed in the coolant. For example, the coolant may flow through piping arranged around each power storage device, or a bag may be arranged between the power storage devices and the coolant may be contained in the bag. It is sufficient that the coolant is thermally connected to the power storage device.

[0058] As described above, exhaust pipe 260 serving as an exhaust unit exhausts gas inside case 240 from case 240. Exhaust pipe 260 extends upward from the top surface of case 240. Note that the exhaust unit of the present disclosure may be an opening of case 240.

[0059] As described above, the filter mechanism 270 is provided in the exhaust pipe 260 and collects the coolant 250, the electrolyte, and the like contained in the gas. The filter mechanism 270 is provided at the tip of the exhaust pipe 260. The filter mechanism of the present disclosure may be provided midway through the exhaust pipe 260. The filter mechanism of the present disclosure may also be provided inside the case 240. The filter mechanism 270 will be described in detail below.

[0060] [Power Storage Device] The power storage device 220 as an example of the second embodiment will be described with reference to FIG.

[0061] In this embodiment, a cylindrical lithium-ion secondary battery is used as the power storage device 220, but a nickel-metal hydride battery, a capacitor, or the like may also be used. The power storage device 220 includes an electrode group 224, for example, in which a strip-shaped positive electrode 221 and a strip-shaped negative electrode 222 are wound with a strip-shaped separator 223 interposed therebetween; a cylindrical outer can 225 that houses the electrode group 224 together with an electrolyte; a sealing member 226 that insulates and seals an opening provided at one axial end of the outer can 225; a foil-shaped positive electrode tab 227 that electrically connects the positive electrode 221 to the sealing member 226; and a negative electrode tab 228 that electrically connects the negative electrode 222 to the outer can 225. An insulating gasket 229 may be disposed between the outer periphery of the sealing member 226 and the inner circumferential surface of the opening of the outer can 225. The outer casing of the power storage device of the present disclosure may be a rectangular outer can or a pouch-shaped outer casing.

[0062] An annular groove 225A is formed on the outer peripheral surface of the outer can 225, on the opening side. This groove 225A is formed as an annular protrusion on the inner peripheral surface of the outer can 225. The gasket 229 and sealing body 226 are disposed on this annular protrusion within the outer can 225. Furthermore, the opening edge of the outer can 225 is crimped so as to be tilted toward the inside of the outer can 225, with the gasket 229 disposed on the inner peripheral side. The crimped opening edge and the protrusion sandwich the sealing body 226 in the axial direction via the gasket 229, thereby sealing the opening of the outer can 225.

[0063] The sealing body 226 is provided with a current interrupter (CID) or a safety valve that ruptures when the pressure inside the outer can 225 reaches or exceeds the operating pressure. An insulating plate 230 is provided between the electrode group 224 and the bottom surface 225B of the outer can 225 or between the electrode group 224 and the protrusion (groove 225A) to insulate the electrode group 224 from the outer can 225. The positive electrode tab 227 extends through a through-hole formed in the insulating plate 230. The negative electrode tab 228 may extend through a through-hole formed in the insulating plate 230 or may extend around the insulating plate 230.

[0064] In the power storage device 220, a positive electrode terminal as a first electrode terminal is provided on the top surface of the sealing body 226, and a negative electrode terminal as a second electrode terminal is provided on the bottom surface 225B of the outer can 225. A positive electrode lead of a positive electrode current collector 233 is joined by welding to the top surface of the sealing body 226, which is the positive electrode terminal as the first electrode terminal. A negative electrode lead of a negative electrode current collector 234 is joined by welding to the bottom surface 225B of the outer can 225, which is the negative electrode terminal as the second electrode terminal.

[0065] [Filter Mechanism] The filter mechanism 270 will be described with reference to FIG.

[0066] As described above, filter mechanism 270 is connected to exhaust pipe 260 and collects coolant 250, electrolyte, etc. contained in the gas. Filter mechanism 270 can reduce white smoke contained in the gas exhausted from case 240, as will be described in detail later.

[0067] Here, when gas containing white smoke is exhausted from the case 240 in the power storage module 210, this includes the occurrence of an abnormality in the power storage device 220. The occurrence of an abnormality in the power storage device 220 includes the occurrence of thermal runaway in the power storage device 220. When the power storage device 220 is experiencing thermal runaway, gas is exhausted from the power storage device 220. This gas may contain the electrolyte solution of the power storage device 220. Furthermore, when the power storage device 220 reaches a high temperature, the coolant 250 vaporizes in a high-temperature, high-pressure environment and is exhausted from the case 240. Furthermore, when the power storage device 220 is experiencing thermal runaway, the coolant 250 becomes mist-like (atomized liquid) in a high-temperature, high-pressure environment and is exhausted from the case 240 as white smoke. In other words, the gas inside case 240 during thermal runaway of power storage device 220 includes high-temperature, high-pressure gas released from power storage device 220, coolant 250 that has evaporated in the high-temperature, high-pressure environment when power storage device 220 reaches a high temperature, coolant 250 that has turned into mist (white smoke) in the high-temperature, high-pressure environment, and other gases. In the following, collection of gas containing mist of coolant 250 is used as an example, but it goes without saying that other gases can also be collected in a similar manner.

[0068] As will be described in detail later, the filter mechanism 270 can reduce the amount of coolant 250 mist contained in the gas exhausted from the case 240 by capturing the coolant 250 that has turned into mist (white smoke) contained in the gas when the power storage device 220 experiences thermal runaway. This can reduce the amount of white smoke contained in the gas. As a result, the reliability of the power storage module 210 can be improved.

[0069] Here, in the initial stage of thermal runaway of the power storage device 220 (for example, from the start to 5 seconds), the coolant 250 in mist form when the power storage device 220 experiences thermal runaway is rapidly exhausted as high-temperature, high-pressure white smoke together with the high-temperature, high-pressure gas exhausted from the power storage device 220. Then, in the subsequent convergence stage (for example, from 5 seconds to 230 seconds after the start), the coolant 250 that has come into contact with the high-temperature power storage device 220 turns into mist and is gradually exhausted as low-temperature, low-pressure white smoke.

[0070] Therefore, for example, if a filter with a small opening rate (high collection efficiency and large pressure loss) is provided in the exhaust section, the pressure loss of the filter will prevent the rapidly generated high-temperature and high-pressure mist of coolant 250 from passing through the filter in the early stage of thermal runaway of power storage device 220, which may result in damage to case 240, exhaust pipe 260, or the filter. On the other hand, for example, if a filter with a large opening rate (low collection efficiency and small pressure loss) is provided in exhaust pipe 260, there is a risk that the mist of coolant 250 will not be collected sufficiently.

[0071] As will be described in detail later, in the initial stage of thermal runaway of the power storage device 220, the internal pressure in the case 240 tends to be higher than a predetermined pressure, and high-pressure coolant mist 250 is collected by passing the gas through the second filter unit 274, which has a large opening rate (low collection efficiency and small pressure loss). In the subsequent convergence stage, the pressure in the case 240 tends to be lower (lower than the predetermined pressure) than in the initial stage of thermal runaway, and low-pressure coolant mist 250 can be collected by passing the gas through the first filter unit 273, which has a small opening rate (high collection efficiency and large pressure loss). This allows the coolant mist 250 to be efficiently collected in accordance with the pressure of the coolant mist 250, which changes depending on the stage of thermal runaway of the power storage device 220. Note that in the power storage module of the present disclosure, it is not necessary for all of the gas generated within the power storage module to pass through the corresponding filter at each stage. For example, in the early stages of thermal runaway, some of the gas within the case 240 may pass through the filter 271 .

[0072] The filter mechanism 270 includes a cylindrical filter 271, the cylindrical interior 271A of which communicates with the exhaust pipe 260, and a partition member 272 disposed within the cylindrical interior 271A of the filter 271, as will be described in detail below. The filter mechanism of the present disclosure does not necessarily have to be cylindrical. It is sufficient that each filter surrounds at least a portion of the space it surrounds (the interior of the cylinder or the interior of the chamber) and is disposed so as to communicate with the space outside the filter mechanism. The portion of the space not surrounded by the filter may be surrounded by a non-porous wall.

[0073] The filter 271 collects the mist-like coolant 250. As described above, the filter 271 is formed in a tubular shape, for example, a cylindrical shape. Note that the filter of the present disclosure may also be formed in a rectangular tubular shape. The filter 271 is disposed so that the axial direction of the filter 271 is parallel to the vertical direction. Note that the filter of the present disclosure may also be disposed so that the axial direction of the filter is parallel to the horizontal direction.

[0074] The filter 271 has a first filter portion 273 and a second filter portion 274 provided downstream of the first filter portion 273 in the exhaust direction, as will be described in detail later.

[0075] The first filter portion 273, which will be described in detail later, collects the mist-like coolant 250 that is slowly exhausted as low-temperature, low-pressure white smoke. The first filter portion 273 is provided on the exhaust upstream side of the filter 271. In other words, a cylindrical interior portion 273A of the first filter portion 273 communicates with the exhaust pipe 260.

[0076] The aperture ratio of the first filter portion 273 is smaller than the aperture ratio of the second filter portion 274. In other words, the collection efficiency of the first filter portion 273 is higher than the collection efficiency of the second filter portion 274. Note that, as a method of controlling the pressure loss of the first filter and the second filter of the present disclosure, the first filter may be made thicker than the second filter while maintaining the aperture ratios of the filters equal. Furthermore, the heat resistance temperature of the first filter portion 273 is lower than the heat resistance temperature of the second filter portion 274.

[0077] The first filter portion 273 may be made of a material such as a HEPA filter, a ULPA filter, a glass fiber filter, a polyester filter, an active carbon filter, a ceramic filter, a polypropylene filter, a fiberglass filter, a nylon filter, a metal mesh filter, etc. The first filter portion 273 may be made of a material different from that of the second filter portion 274, or may be made of the same material as the second filter portion 274 but with a smaller opening rate than the second filter portion 274, or may be made of the same material as the second filter portion 274 but with a greater thickness than the second filter portion 274.

[0078] As will be described in detail later, the first filter section 273 can capture the mist-like coolant 250 that comes into contact with the high-temperature storage device 220 during the convergence stage, and is gradually discharged as low-temperature, low-pressure white smoke.

[0079] The second filter part 274, which will be described in detail later, captures the mist of coolant 250 that is suddenly exhausted as high-temperature, high-pressure white smoke. As described above, the second filter part 274 is provided downstream of the first filter part 273 in the exhaust direction.

[0080] The aperture ratio of the second filter portion 274 is greater than that of the first filter portion 273. In other words, the collection efficiency of the second filter portion 274 is lower than that of the first filter portion 273. Note that, as a method of controlling the pressure loss of the first filter and the second filter of the present disclosure, the second filter may be thinner than the first filter while maintaining the aperture ratios of the filters equal. Furthermore, the heat resistance temperature of the second filter portion 274 is higher than that of the first filter portion 273.

[0081] The second filter portion 274 may be made of a material such as a HEPA filter, a ULPA filter, a glass fiber filter, a polyester filter, an active carbon filter, a ceramic filter, a polypropylene filter, a fiberglass filter, a nylon filter, a metal mesh filter, etc. The second filter portion 274 may be made of a material different from that of the first filter portion 273, or may be made of the same material as the first filter portion 273 but with a larger opening rate than the first filter portion 273, or may be made of the same material as the first filter portion 273 but with a smaller thickness than the first filter portion 273.

[0082] As will be described in detail later, the second filter section 274 can capture the mist-like coolant 250 that is suddenly exhausted as high-temperature, high-pressure white smoke together with the high-temperature, high-pressure gas exhausted from the power storage device 220 in the initial stage described above.

[0083] The partition member 272 separates the cylindrical interior 273A of the first filter section 273 from the cylindrical interior 274A of the second filter section 274. As described above, the partition member 272 is disposed in the cylindrical interior 271A of the filter 271. The partition member 272 is formed, for example, in a spherical shape. However, the partition member of the present disclosure may also be formed in a cylindrical shape.

[0084] When the pressure inside tubular interior 271A of filter 271 is equal to or higher than the set pressure, partition member 272 is located inside tubular interior 274A of second filter section 274, and when the pressure inside tubular interior 271A of filter 271 is less than the set pressure, partition member 272 is located inside tubular interior 273A of first filter section 273. When the pressure inside tubular interior 271A of filter 271 is less than the set pressure, partition member 272 is preferably located near the boundary between tubular interior 273A of first filter section 273 and tubular interior 274A of second filter section 274. However, when the power storage module is in a normal state, partition member 272 may be located at the upstream end of tubular interior 271A of filter 271.

[0085] More specifically, the partition member 272 is supported by a spring 275. The spring constant of the spring 275 is set so that, when the pressure inside the tube 271A of the filter 271 is equal to or higher than the set pressure, the pressing force (upward force) of the exhausted gas and the resultant force (downward force) of the gravity of the partition member 272 and the restoring force of the spring 275 are balanced, and the partition member 272 is positioned inside the tube 274A of the second filter part 274. Furthermore, the spring constant of the spring 275 is set so that, when the pressure inside the tube 271A of the filter 271 is lower than the set pressure, the resultant force (upward force) of the pressing force of the exhausted gas and the restoring force of the spring 275 is balanced, and the gravity of the partition member 272 (downward force) is positioned, and the partition member 272 is positioned inside the tube 273A of the first filter part 273.

[0086] The set pressure is lower than the operating pressure of the exhaust valve of the power storage module, for example, set slightly lower than the set pressure of this exhaust valve. This exhaust valve may be operated to discharge the gas outside the power storage module 210 when a large amount of gas is suddenly generated inside the power storage module 210 and the exhaust volume by the filter 271 is not enough to exhaust the gas in time.

[0087] It should be noted that the partition member of the present disclosure does not have to be supported by spring 275. In this configuration, the gravity of the partition member may be set so that, when the pressure in cylindrical interior 271A of filter 271 is equal to or greater than the set pressure, the pressing force (upward force) of the exhausted gas and the gravity (downward force) of partition member 272 are balanced, and the partition member is positioned in cylindrical interior 274A of second filter section 274. Furthermore, the gravity of the partition member may be set so that, when the pressure in cylindrical interior 271A of filter 271 is less than the set pressure, the pressing force (upward force) of the exhausted gas and the gravity (downward force) of partition member 272 are balanced, and the partition member is positioned in cylindrical interior 273A of first filter section 273.

[0088] With the above configuration, when the pressure inside the tube 271A of the filter 271 is less than the set pressure, the partition member 272 moves to the inside tube 273A of the first filter part 273, and when the pressure inside the tube 271A of the filter 271 is equal to or greater than the set pressure, the partition member 272 moves to the inside tube 273A of the first filter part 273.

[0089] Other Embodiments (Filter Mechanism) The filter mechanism of the present disclosure is not limited to the above-described embodiments, and may have a configuration in which three or more filter sections are provided along the axial direction. In such a configuration, it is preferable that the pressure loss of the filter sections decreases, the capture efficiency of the filter sections decreases, and the heat resistance temperature of the filter sections increases from the upstream side to the downstream side of the exhaust gas.

[0090] The filter mechanism of the present disclosure is not limited to the above embodiment, and may be configured such that the filter is made of a single material and the aperture ratio of the filter varies along the axial direction. In such a configuration, it is preferable that the pressure loss of the filter portion decreases, the capture efficiency of the filter portion decreases, and the heat resistance temperature of the filter portion increases from the upstream side of the exhaust gas to the downstream side.

[0091] The operation of the filter mechanism 270 will be described with reference to FIGS.

[0092] 9 , in the initial stage of thermal runaway of the power storage device 220, high-temperature, high-pressure mist of coolant 250 is rapidly exhausted together with the gas exhausted from the power storage device 220, and it is difficult for the mist to pass through the first filter portion 273, which has a large pressure loss. At this time, the pressure in the cylindrical interior 271A of the filter 271 exceeds the set pressure, and the partition member 272 moves to the cylindrical interior 274A of the second filter portion 274. As a result, the high-temperature, high-pressure mist of coolant 250 can pass through the second filter portion 274, which has a small pressure loss, and is collected by the second filter portion 274.

[0093] 10 , in the subsequent convergence stage of the thermal runaway of the power storage device 220, the low-temperature, low-pressure mist of coolant 250 that has been in contact with the high-temperature power storage device 220 is slowly exhausted and can pass through the first filter portion 273, which has a large pressure loss. At this time, the low-temperature, low-pressure mist of coolant 250 is collected by the first filter portion 273. At this time, the pressure in the cylindrical interior 271A of the filter 271 becomes lower than the set pressure, and the partition member 272 moves into the cylindrical interior 273A of the first filter portion 273.

[0094] [Overall Configuration of Power Storage Module (Third Embodiment)] A power storage module 310 as an example of a third embodiment will be described with reference to FIG.

[0095] The power storage module 310 includes at least one power storage device 320 (multiple in this embodiment), a case 340 that houses the at least one power storage device 320, a coolant 350 in which the at least one power storage device 320 is immersed within the case 340, an exhaust pipe 360 ​​as an exhaust section that exhausts gas within the case 340 from the case 340, and a filter mechanism 370 that is provided in the exhaust pipe 360 ​​and collects the coolant 350, electrolyte, etc. contained in the gas. Note that the power storage module of the present disclosure may include only one power storage device 320.

[0096] The multiple power storage devices 320 may be packed as densely as possible within the power storage module 310 while taking safety into consideration, and adjacent power storage devices 320 may be arranged in close proximity to each other. For example, the power storage devices 320 may be arranged such that six power storage devices 320 surround one power storage device 320 in a plan view (or arranged in a staggered pattern). Furthermore, the multiple power storage devices 320 may be arranged such that the power storage devices 320 closest to each other are located on all four sides. Details of the power storage devices 320 will be described later.

[0097] The upper side of the power storage device 320 is held by an upper holder 331. The upper holder 331 is made of, for example, a thermoplastic resin. Examples of the thermoplastic resin include polycarbonate, polyethylene, polypropylene, polyamide, and ABS.

[0098] A positive current collector 333 is disposed on the upper surface of the upper holder 331. The positive current collector 333 connects positive terminals serving as first electrode terminals of the power storage device 320, which will be described later. The positive current collector 333 is immersed in the coolant 350 inside the case 340. Note that the amount of the coolant 350 and the positional relationship between the positive current collector 333 and the coolant 350 are not limited to these. The positive current collector 333 is formed from a conductive metal plate.

[0099] The lower side of the power storage device 320 is held by a lower holder 332. The lower holder 332 is made of, for example, a thermoplastic resin. Examples of the thermoplastic resin include polycarbonate, polyethylene, polypropylene, polyamide, and ABS.

[0100] A negative current collector 334 is disposed on the lower surface of the lower holder 332. The negative current collector 334 connects negative terminals serving as second electrode terminals of the power storage device 320, which will be described later. The negative current collector 334 is immersed in the coolant 350 inside the case 340. Note that the amount of the coolant 350 and the positional relationship between the negative current collector 334 and the coolant 350 are not limited to these. The negative current collector 334 is formed from a conductive metal plate.

[0101] In the power storage module of the present disclosure, for example, the positive electrode current collector plate 333 and the negative electrode current collector plate 334 may be arranged together at one end of the power storage device 320 .

[0102] As described above, case 340 houses at least one power storage device 320. Case 340 is made of a metal such as aluminum or resin, and is formed into a substantially rectangular parallelepiped shape. Case 340 can protect power storage device 320 housed therein from dust and water.

[0103] As described above, the coolant 350 immerses at least one power storage device 320 within the case 340. In the power storage module 310, the coolant 350 can cool the power storage device 320. This improves the reliability of the power storage module 310. The coolant 350 has insulating properties. This prevents the power storage device 320 from leaking current to other power storage devices 320 via the coolant 350. The coolant 350 may be, for example, insulating oil, transformer oil, silicone oil, or a fluorine-based inert liquid such as hydrofluoroether. Note that in the power storage module of the present disclosure, the power storage devices do not need to be immersed in the coolant. For example, the coolant may flow through piping arranged around each power storage device, or a bag may be arranged between the power storage devices and the coolant may be contained in the bag. It is sufficient that the coolant is thermally connected to the power storage device.

[0104] As described above, exhaust pipe 360 ​​serving as an exhaust unit exhausts gas inside case 340 from case 340. Exhaust pipe 360 ​​extends horizontally from the upper end of the side surface of case 340. Note that the exhaust unit of the present disclosure may be an opening of case 340.

[0105] As described above, the filter mechanism 370 is provided in the exhaust pipe 360 ​​and collects the coolant 350, the electrolyte, and the like contained in the gas. The filter mechanism 370 is provided at the tip of the exhaust pipe 360. Note that the filter mechanism of the present disclosure may also be provided inside the case 340. The filter mechanism 370 will be described in detail below.

[0106] [Power Storage Device] A power storage device 320 as an example of the third embodiment will be described with reference to FIG.

[0107] In this embodiment, a cylindrical lithium-ion secondary battery is used as the power storage device 320, but a nickel-metal hydride battery, a capacitor, or the like may also be used. The power storage device 320 includes an electrode group 324, for example, in which a strip-shaped positive electrode 321 and a strip-shaped negative electrode 322 are wound with a strip-shaped separator 323 interposed therebetween; a cylindrical outer can 325 that houses the electrode group 324 together with an electrolyte; a sealing member 326 that insulates and seals an opening provided at one axial end of the outer can 325; a foil-shaped positive electrode tab 327 that electrically connects the positive electrode 321 to the sealing member 326; and a negative electrode tab 328 that electrically connects the negative electrode 322 to the outer can 325. An insulating gasket 329 may be disposed between the outer periphery of the sealing member 326 and the inner circumferential surface of the opening of the outer can 325. The outer casing of the power storage device of the present disclosure may be a rectangular outer can or a pouch-shaped outer casing.

[0108] An annular groove 325A is formed on the outer peripheral surface of the outer can 325, on the opening side. This groove 325A is formed as an annular protrusion on the inner peripheral surface of the outer can 325. The gasket 329 and sealing body 326 are disposed on this annular protrusion within the outer can 325. Furthermore, the opening edge of the outer can 325 is crimped so as to bend toward the inside of the outer can 325, with the gasket 329 disposed on the inner peripheral side. The crimped opening edge and the protrusion sandwich the sealing body 326 in the axial direction via the gasket 329, thereby sealing the opening of the outer can 325.

[0109] The sealing body 326 is provided with a current interrupter (CID) or a safety valve that ruptures when the pressure inside the outer can 325 reaches or exceeds the activation pressure. An insulating plate 330 is provided between the electrode group 324 and the bottom surface 325B of the outer can 325 or between the electrode group 324 and the protrusion (groove 325A) to insulate the electrode group 324 from the outer can 325. The positive electrode tab 327 extends through a through-hole formed in the insulating plate 330. The negative electrode tab 328 may extend through a through-hole formed in the insulating plate 330 or may extend around the insulating plate 330.

[0110] In the power storage device 320, a positive electrode terminal as a first electrode terminal is provided on the top surface of the sealing body 326, and a negative electrode terminal as a second electrode terminal is provided on the bottom surface 325B of the outer can 325. A positive electrode lead of a positive electrode current collector 333 is joined by welding to the top surface of the sealing body 326, which is the positive electrode terminal as the first electrode terminal. A negative electrode lead of a negative electrode current collector 334 is joined by welding to the bottom surface 325B of the outer can 325, which is the negative electrode terminal as the second electrode terminal.

[0111] [Filter Mechanism] The filter mechanism 370 will be described with reference to FIG.

[0112] As described above, filter mechanism 370 is connected to exhaust pipe 360 ​​and collects coolant 350, electrolyte, etc. contained in the gas. Filter mechanism 370 can reduce white smoke contained in the gas exhausted from case 340, as will be described in detail later.

[0113] Here, when gas containing white smoke is exhausted from the case 340 of the power storage module 310, this includes the occurrence of an abnormality in the power storage device 320. The occurrence of an abnormality in the power storage device 320 includes the occurrence of thermal runaway in the power storage device 320. When the power storage device 320 experiences thermal runaway, gas is exhausted from the power storage device 320. This gas may contain the electrolyte of the power storage device 320. Furthermore, when the power storage device 320 reaches a high temperature, the coolant 350 vaporizes under a high-temperature and high-pressure environment and is exhausted from the case 340. Furthermore, when the power storage device 320 experiences thermal runaway, the coolant 350 becomes mist-like (atomized liquid) under a high-temperature and high-pressure environment and is exhausted from the case 340 as white smoke. In other words, the gas inside case 340 during thermal runaway of power storage device 320 includes high-temperature, high-pressure gas released from power storage device 320, coolant 350 that has evaporated in the high-temperature, high-pressure environment when power storage device 320 reaches a high temperature, coolant 350 that has turned into mist (white smoke) in the high-temperature, high-pressure environment, and other gases. In the following, the collection of gas containing mist of coolant 350 is used as an example, but it goes without saying that other gases can also be collected in a similar manner.

[0114] As will be described in detail later, the filter mechanism 370 can reduce the amount of coolant 350 mist (white smoke) contained in the gas exhausted from the case 340 by capturing the coolant 350 in mist form (white smoke) contained in the gas when the power storage device 320 experiences thermal runaway. This can reduce the amount of white smoke contained in the gas. As a result, the reliability of the power storage module 310 can be improved.

[0115] Here, in the initial stage of thermal runaway of the power storage device 320 (for example, from the start to 5 seconds), the coolant 350 in mist form when the power storage device 320 experiences thermal runaway is rapidly exhausted as high-temperature, high-pressure white smoke together with the high-temperature, high-pressure gas exhausted from the power storage device 320. Then, in the subsequent convergence stage (for example, from 5 seconds to 330 seconds after the start), the coolant 350 that has come into contact with the high-temperature power storage device 320 turns into mist and is gradually exhausted as low-temperature, low-pressure white smoke.

[0116] Therefore, for example, if a filter with a small opening rate (high collection efficiency and large pressure loss) is provided in the exhaust section, the pressure loss of the filter makes it difficult for the rapidly generated high-temperature and high-pressure mist of coolant 350 to pass through the filter in the early stage of thermal runaway of power storage device 320, and there is a risk of damage to case 340, exhaust pipe 360, or the filter. On the other hand, for example, if a filter with a large opening rate (low collection efficiency and small pressure loss) is provided in exhaust pipe 360, there is a risk that the mist of coolant 350 cannot be sufficiently collected.

[0117] As will be described in detail later, in the initial stage of thermal runaway of the power storage device 320, the internal pressure in the case 340 tends to be higher than a predetermined pressure, and high-pressure coolant mist 350 is collected by passing the gas through the second filter 374, which has a large opening rate (low collection efficiency and small pressure loss). In the subsequent convergence stage, the pressure in the case 340 tends to be lower (lower than the predetermined pressure) than in the initial stage of thermal runaway, and low-pressure coolant mist 350 can be collected by passing the gas through the first filter 373, which has a small opening rate (high collection efficiency and large pressure loss). This allows the coolant mist 350 to be efficiently collected in accordance with the pressure of the coolant mist 350, which changes depending on the stage of thermal runaway of the power storage device 320. Note that in the power storage module of the present disclosure, it is not necessary for all of the gas generated within the power storage module to pass through the corresponding filter at each stage. For example, in the early stages of thermal runaway, some of the gas inside the case 340 may pass through the first filter 373 .

[0118] The filter mechanism 370 includes a first exhaust pipe 371 branching off from the exhaust pipe 360, a first filter 373 provided on the first exhaust pipe 371, a second exhaust pipe 372 branching off from the exhaust pipe 360, a second filter 374 provided on the second exhaust pipe 372, and a resettable safety valve 375 provided downstream of the second filter 374 on the second exhaust pipe 372, which opens the second exhaust pipe 372 when the pressure inside the first exhaust pipe 371 is equal to or higher than the set pressure, and closes the second exhaust pipe 372 when the pressure inside the first exhaust pipe 371 is lower than the set pressure, as will be described in detail below.

[0119] The first filter 373, as will be described in detail later, collects the mist-like coolant 350 that is slowly exhausted as low-temperature, low-pressure white smoke. As described above, the first filter 373 is provided at the tip end of the first exhaust pipe 371. The first filter of the present disclosure may also be provided midway through the first exhaust pipe 371. The first filter 373 is formed, for example, in a cylindrical shape. The first filter of the present disclosure may also be formed in a columnar shape or the like. The first filter of the present disclosure only needs to surround at least a portion of the space (chamber) that it surrounds, and the remaining portion of the space may be surrounded by a non-porous wall.

[0120] The aperture ratio of the first filter 373 is smaller than that of the second filter 374. In other words, the collection efficiency of the first filter 373 is higher than that of the second filter 374. Note that, as a method of controlling the pressure loss of the first filter and the second filter of the present disclosure, the first filter may be made thicker than the second filter while maintaining the aperture ratios of the filters equal. Furthermore, the heat resistance temperature of the first filter 373 is lower than that of the second filter 374.

[0121] The first filter 373 may be made of a material such as a HEPA filter, a ULPA filter, a glass fiber filter, a polyester filter, an active carbon filter, a ceramic filter, a polypropylene filter, a fiberglass filter, a nylon filter, a metal mesh filter, etc. The first filter 373 may be made of a different material from the second filter 374, or may be made of the same material as the second filter 374 but with a smaller opening ratio than the second filter 374.

[0122] As will be described in detail later, the first filter 373 can capture the mist-like coolant 350 that comes into contact with the high-temperature power storage device 320 during the convergence stage, and is gradually discharged as low-temperature, low-pressure white smoke.

[0123] The second filter 374, as will be described in detail later, captures the mist-like coolant 350 that is rapidly exhausted as high-temperature, high-pressure white smoke. As described above, the second filter 374 is provided at the tip end of the second exhaust pipe 372. The second filter of the present disclosure may also be provided midway along the second exhaust pipe 372. The second filter 374 is formed, for example, in a cylindrical shape. The second filter of the present disclosure may also be formed in a columnar shape or the like. The second filter of the present disclosure only needs to surround at least a portion of the space (chamber) that it surrounds, and the remaining portion of the space may be surrounded by a non-porous wall.

[0124] The aperture ratio of the second filter 374 is greater than that of the first filter 373. In other words, the capture ratio of the second filter 374 is lower than that of the first filter 373. Note that, as a method of controlling the pressure loss of the first filter and the second filter of the present disclosure, the second filter may be thinner than the first filter while maintaining the aperture ratios of the filters equal. Furthermore, the heat resistance temperature of the second filter 374 is higher than that of the first filter 373.

[0125] The second filter 374 may be made of a material such as a HEPA filter, a ULPA filter, a glass fiber filter, a polyester filter, an active carbon filter, a ceramic filter, a polypropylene filter, a fiberglass filter, a nylon filter, a metal mesh filter, etc. The second filter 374 may be made of a material different from that of the first filter 373, or may be made of the same material as the first filter 373 but with a larger opening ratio than the first filter 373.

[0126] As will be described in detail later, the second filter 374 can capture the mist-like coolant 350 that is suddenly exhausted as high-temperature, high-pressure white smoke together with the high-temperature, high-pressure gas exhausted from the power storage device 320 in the initial stage described above.

[0127] As described above, the resettable safety valve 375 is provided on the second exhaust pipe 372 upstream of the second filter 374. As described above, the resettable safety valve 375 opens the second exhaust pipe 372 when the pressure in the first exhaust pipe 371 is equal to or greater than the set pressure, and closes the second exhaust pipe 372 when the pressure in the first exhaust pipe 371 is less than the set pressure. The resettable safety valve 375 is a so-called self-resetting safety valve that opens when the pressure reaches the set pressure and closes when the pressure drops below the set pressure. The set pressure is lower than the set pressure of the exhaust valve of the power storage module 310, for example, set slightly lower than the set pressure of the exhaust valve. This exhaust valve may be activated to discharge the gas outside the power storage module when a large amount of gas is suddenly generated inside the power storage module 310 and the exhaust volume of the second filter 374 is not enough to exhaust the gas in time.

[0128] According to the return type safety valve 375, in the initial stage described above, the mist-like coolant 350 that is suddenly exhausted as high-temperature, high-pressure white smoke together with the high-temperature, high-pressure gas exhausted from the power storage device 320 can pass through the second filter 374 via the second exhaust pipe 372.

[0129] The operation of the filter mechanism 370 will be described with reference to FIGS.

[0130] 14 , in the initial stage of thermal runaway of the power storage device 320, high-temperature, high-pressure mist of coolant 350 is rapidly exhausted together with the gas exhausted from the power storage device 320, and it is difficult for the mist to pass through the first filter 373, which has a large pressure loss. On the other hand, the pressure inside the first exhaust pipe 371 exceeds the set pressure, causing the return safety valve 375 to open, and the high-temperature, high-pressure mist of coolant 350 passes through the second exhaust pipe 372 and the second filter 374, which has a small pressure loss, and is collected by the second filter 374.

[0131] 15 , in the subsequent stage where the thermal runaway of the power storage device 320 is resolved, the low-temperature, low-pressure mist of coolant 350 that has been in contact with the high-temperature power storage device 320 is slowly exhausted and can pass through the first filter 373, which has a large pressure loss. At this time, the low-temperature, low-pressure mist of coolant 350 is collected by the first filter 373. At this time, the pressure inside the first exhaust pipe 371 falls below the set pressure, and the reset safety valve 375 closes.

[0132] [Summary] The present disclosure will be 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; an exhaust section that exhausts gas inside the case from the case; and a filter mechanism that is provided in the exhaust section and through which the gas passes, the filter mechanism having a first filter and a second filter, and a pressure loss of the first filter being greater than a pressure loss of the second filter. Configuration 2: The energy storage module according to configuration 1, wherein when the pressure inside the case exceeds a predetermined pressure, the gas passes through the second filter, and when the pressure inside the case is equal to or lower than the predetermined pressure, the gas passes through the first filter. Configuration 3: The energy storage module according to configuration 2, wherein the first filter and the second filter are cylindrical, the first filter is housed within the second filter, and the first filter is in communication with the inside of the case. Configuration 4: The energy storage module according to configuration 2, further comprising a coolant thermally connected to the at least one energy storage device, wherein the coolant contained in the gas is collected in the filter mechanism.Configuration 5: The energy storage module according to configuration 4, wherein the coolant is contained in the case, and wherein the at least one energy storage device is immersed in the coolant.Configuration 6: The energy storage module according to configuration 3, wherein the filter mechanism further comprises a resettable safety valve disposed inside the cylinder of the first filter, the resettable safety valve communicating the inside of the cylinder of the first filter with the inside of the cylinder of the second filter when the inside of the cylinder of the first filter is at or above a set pressure, and isolating the inside of the cylinder of the first filter from the inside of the cylinder of the second filter when the inside of the cylinder of the first filter is below the set pressure.Configuration 7: The energy storage module according to configuration 6, wherein the heat-resistant temperature of the first filter is lower than the heat-resistant temperature of the second filter.Configuration 8: The energy storage module according to configuration 6 or 7, further comprising an exhaust valve that operates when the pressure inside the case exceeds a predetermined pressure and exhausts the gas inside the case, wherein the set pressure of the return type safety valve is lower than the operating pressure of the valve. Configuration 9: The energy storage module according to configuration 1, wherein the filter mechanism has a cylindrical filter, wherein the filter has a first filter section and a second filter section that is provided downstream of the first filter section and on one side in the axial direction of the exhaust, and wherein the pressure loss of the first filter section is greater than the pressure loss of the second filter section. Configuration 10: The energy storage module according to configuration 9, further comprising a coolant that is thermally connected to the at least one energy storage device. Configuration 11: The energy storage module according to configuration 10, wherein at least one energy storage device is immersed in the coolant contained in the case. Configuration 12: The energy storage module according to configuration 9, wherein the filter mechanism further includes a partition member disposed inside the cylindrical portion of the filter and movable inside the cylindrical portion of the filter.Configuration 13: The energy storage module according to configuration 12, wherein the partition member is located inside the cylindrical portion of the second filter section when the pressure inside the cylindrical portion of the filter is equal to or higher than a set pressure, and is located inside the cylindrical portion of the first filter section when the pressure inside the cylindrical portion of the filter is lower than the set pressure.Configuration 14: The energy storage module according to configuration 13, wherein the set pressure is lower than the set pressure of an exhaust valve of the energy storage module.Configuration 15: The energy storage module according to configuration 14, wherein the partition member is supported by a spring.Configuration 16: The energy storage module according to any one of configurations 9 to 15, wherein the filter is made of the same material as the first filter section and the second filter section, and wherein the opening ratio varies along the axial direction.Configuration 17: The energy storage module according to any one of configurations 9 to 15, wherein the first filter portion and the second filter portion of the filter are made of different materials. Configuration 18: The energy storage module according to claim 17, wherein the heat resistance temperature of the first filter portion is lower than the heat resistance temperature of the second filter portion. Configuration 19: The energy storage module of configuration 1, wherein the filter mechanism includes a first exhaust pipe branching off from the exhaust portion, a first filter provided in the first exhaust pipe, a second exhaust pipe branching off from the exhaust portion, and a second filter provided in the second exhaust pipe, and wherein a pressure loss of the first filter is greater than a pressure loss of the second filter. Configuration 20: The energy storage module according to configuration 19, further comprising a coolant thermally connected to at least one of the energy storage devices. Configuration 21: The power storage module according to configuration 20, wherein at least one of the power storage devices is immersed in the coolant housed in the case.Configuration 22: The power storage module according to configuration 19, wherein the filter mechanism is provided in the second exhaust pipe upstream of the second filter, and further includes a resettable safety valve that opens the second exhaust pipe when the pressure in the first exhaust pipe is equal to or greater than a set pressure and closes the second exhaust pipe when the pressure in the first exhaust pipe is below the set pressure.Configuration 23: The power storage module according to configuration 22, wherein the heat resistance temperature of the second filter is higher than the heat resistance temperature of the first filter.Configuration 24: The power storage module according to configuration 22 or 23, further including an exhaust valve that operates when the pressure in the case exceeds a predetermined pressure and exhausts the gas inside the case, and wherein the set pressure of the resettable safety valve is lower than the set pressure of the exhaust valve.

[0133] 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.

[0134] REFERENCE SIGNS LIST 110 Energy storage module, 120 Energy storage device, 121 Positive electrode, 122 Negative electrode, 123 Separator, 124 Electrode group, 125 Outer can, 125A Groove, 125B Bottom surface, 126 Sealing body, 127 Positive electrode tab, 128 Negative electrode tab, 129 Gasket, 130 Insulating plate, 131 Upper holder, 132 Lower holder, 133 Positive electrode current collector, 134 Negative electrode current collector, 140 Case, 150 Coolant, 160 Exhaust pipe, 170 Filter mechanism, 171 First filter, 171A Cylinder interior, 172 Second filter, 172A Cylinder interior, 174 Resettable safety valve, 175 Side plate, 210 Energy storage module, 220 Energy storage device, 221 Positive electrode, 222 Negative electrode, 223 Separator, 224 Electrode group, 225 Outer can, 225A Groove, 225B Bottom, 226 Sealing body, 227 Positive electrode tab, 228 Negative electrode tab, 229 Gasket, 230 Insulating plate, 231 Upper holder, 232 Lower holder, 233 Positive electrode current collector, 234 Negative electrode current collector, 240 Case, 250 Coolant, 260 Exhaust pipe, 270 Filter mechanism, 271 Filter, 272 Partition member, 273 First filter section, 274 Second filter section, 275 Spring, 310 Energy storage module, 320 Energy storage device, 321 Positive electrode, 322 Negative electrode, 323 Separator, 324 Electrode group, 325 Outer can, 325A Groove, 325B Bottom surface, 326 sealing body, 327 positive electrode tab, 328 negative electrode tab, 329 gasket, 330 insulating plate, 331 upper holder, 332 lower holder, 333 positive electrode current collector, 334 negative electrode current collector, 340 case, 350 coolant, 360 exhaust pipe, 370 filter mechanism, 371 first exhaust pipe, 372 second exhaust pipe, 373 first filter, 374 second filter, 375 resettable safety 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; an exhaust section that exhausts gas inside the case from the case; and a filter mechanism that is provided in the exhaust section and through which the gas passes, the filter mechanism having a first filter and a second filter, and the pressure loss of the first filter being greater than the pressure loss of the second filter.

2. An energy storage module according to claim 1, wherein when the pressure inside the case exceeds a predetermined pressure, the gas passes through the second filter, and when the pressure inside the case is equal to or lower than the predetermined pressure, the gas passes through the first filter.

3. An energy storage module according to claim 2, wherein the first filter and the second filter are cylindrical, the first filter is housed within the second filter, and the first filter communicates with the inside of the case.

4. An electric storage module according to claim 2, further comprising a coolant thermally connected to said at least one electric storage device, wherein said coolant contained in said gas is collected in said filter mechanism.

5. An electric storage module according to claim 4, wherein the cooling liquid is contained within the case, and at least one electric storage device is immersed in the cooling liquid.

6. An energy storage module according to claim 3, wherein the filter mechanism further comprises a resettable safety valve that covers the inside of the tube of the first filter, communicates the inside of the tube of the first filter with the inside of the tube of the second filter when the pressure inside the tube of the first filter is equal to or higher than a set pressure, and blocks the inside of the tube of the first filter from the inside of the tube of the second filter when the pressure inside the tube of the first filter is lower than the set pressure.

7. The energy storage module according to claim 6, wherein the heat-resistant temperature of the first filter is lower than the heat-resistant temperature of the second filter.

8. An energy storage module according to claim 6 or 7, further comprising an exhaust valve that operates when the pressure inside the case exceeds a predetermined pressure to exhaust the gas inside the case, and the set pressure of the return type safety valve is lower than the operating pressure of the valve.

9. An energy storage module according to claim 1, wherein the filter mechanism has a filter formed in a cylindrical shape, the inside of the cylinder being in communication with the exhaust section, the filter having a first filter section and a second filter section provided downstream of the first filter section in the exhaust direction, and the pressure loss of the first filter section is greater than the pressure loss of the second filter section.

10. The energy storage module of claim 9, further comprising a cooling fluid in thermal communication with said at least one energy storage device.

11. The energy storage module according to claim 10, wherein at least one of the energy storage devices is immersed in the cooling liquid contained in the case.

12. An electric storage module according to claim 9, wherein the filter mechanism further comprises a partition member disposed inside the cylindrical portion of the filter and movable within the cylindrical portion of the filter.

13. An energy storage module according to claim 12, wherein the partition member is located inside the tube of the second filter section when the pressure inside the filter tube is equal to or higher than a set pressure, and is located inside the tube of the first filter section when the pressure inside the filter tube is lower than the set pressure.

14. The energy storage module according to claim 13, wherein the set pressure is lower than the set pressure of an exhaust valve of the energy storage module.

15. The energy storage module according to claim 14, wherein the partition member is supported by a spring.

16. An energy storage module according to any one of claims 9 to 15, wherein the filter is made of the same material as the first filter section and the second filter section, and the aperture ratio varies along the axial direction.

17. An energy storage module according to any one of claims 9 to 15, wherein the first filter section and the second filter section of the filter are made of different materials.

18. The energy storage module according to claim 17, wherein the heat-resistant temperature of the first filter section is lower than the heat-resistant temperature of the second filter section.

19. An energy storage module as described in claim 1, wherein the filter mechanism comprises a first exhaust pipe branching off from the exhaust section, a first filter provided in the first exhaust pipe, a second exhaust pipe branching off from the exhaust section, and a second filter provided in the second exhaust pipe, and the pressure loss of the first filter is greater than the pressure loss of the second filter.

20. The energy storage module of claim 19, further comprising a cooling fluid in thermal communication with at least one of said energy storage devices.

21. The energy storage module according to claim 20, wherein at least one of the energy storage devices is immersed in the cooling liquid contained in the case.

22. An energy storage module according to claim 19, wherein the filter mechanism is provided on the exhaust upstream side of the second filter in the second exhaust pipe, and further comprises a resettable safety valve that opens the second exhaust pipe when the pressure in the first exhaust pipe is equal to or greater than a set pressure, and closes the second exhaust pipe when the pressure in the first exhaust pipe is less than the set pressure.

23. The energy storage module according to claim 22, wherein the heat-resistant temperature of the second filter is higher than the heat-resistant temperature of the first filter.

24. An energy storage module according to claim 22 or 23, further comprising an exhaust valve that operates when the pressure inside the case exceeds a predetermined pressure and exhausts the gas inside the case, and the set pressure of the return type safety valve is lower than the set pressure of the exhaust valve.

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