WO2022012449A1

WO2022012449A1 - Passive fire extinguishing device and battery pack

Info

Publication number: WO2022012449A1
Application number: PCT/CN2021/105652
Authority: WO
Inventors: 李飞; 姜乃文; 张尧; 周兴才; 刘海涛; 王宇豪
Original assignee: 哲弗智能系统（上海）有限公司
Priority date: 2020-07-16
Filing date: 2021-07-12
Publication date: 2022-01-20

Abstract

A passive fire extinguishing device and a battery pack. The present passive fire extinguishing device comprises a fire extinguishing device housing, the fire extinguishing device housing enclosing a sealed space. The sealed space is internally provided with a fire extinguishant and a compressed gas. The fire extinguishing device housing is to be arranged on end covers of a plurality of battery modules, or on safety valves of a plurality of battery cells in a plurality of battery modules. When thermal runaway occurs in a battery cell, an end cover or a safety valve opens, the fire extinguishing device housing is broken, and the fire extinguishant is sprayed into the end cover or the safety valve.

Description

Passive fire extinguishing device and battery pack

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application with the application number 2020106887616 filed with the China Patent Office on July 16, 2020 and the Chinese patent application with the application number 2020214070710 filed with the China Patent Office on July 16, 2020. The entire contents of the patent application are incorporated herein by reference.

technical field

The present application relates to the technical field of lithium ion batteries, and in particular, to a passive fire extinguishing device and a battery pack.

Background technique

Today's world attaches great importance to environmental protection, technological progress and energy security issues, making new energy electric vehicles one of the hottest topics today. All countries and major car companies in the world are also vigorously developing new energy electric vehicles as the main means of transportation to replace the original fuel vehicles. In this context, the energy density of lithium-ion batteries used in new energy electric vehicles continues to increase, and the scale of batteries continues to expand. While increasing the cruising range, it also makes the thermal runaway risk and harm of lithium-ion batteries more and more serious. The thermal runaway risk of lithium-ion batteries has been widely recognized as one of the key issues limiting the development of new energy vehicles. How to ensure that the lithium-ion battery system can still ensure the safety of the outside of the battery pack, vehicles and personnel when thermal runaway occurs due to external action or internal triggering is imminent.

However, when the lithium-ion battery is thermally out of control, the traditional lithium-ion battery fire extinguishing device mostly adopts the control valve, fire extinguishing agent release pipeline, sensor detection and controller to control the spray of fire extinguishing agent, so as to realize the occurrence of fire in the battery box. Put out the fire after the fire. The control structure of the entire control system of the traditional lithium-ion battery fire extinguishing device is complex, and the fire extinguishing cannot be carried out in time, resulting in low fire extinguishing efficiency.

SUMMARY OF THE INVENTION

According to various embodiments of the present application, a passive fire extinguishing device and a battery pack are provided.

A passive fire extinguishing device is applied to a battery pack, and the battery includes a battery module. The battery module includes a plurality of battery cells, and the battery cells are provided with safety valves. The battery module has end caps. The passive fire extinguishing device includes a fire extinguishing device housing. The casing of the fire extinguishing device is surrounded to form a sealed space. A fire extinguishing agent and a compressed gas are arranged in the sealed space. The fire extinguishing device casing is used to be disposed on the end caps of a plurality of battery modules or the safety valves of a plurality of battery cells. When the thermal runaway of the battery cell occurs, the end cover or the safety valve is opened, the casing of the fire extinguishing device is ruptured, and the fire extinguishing agent is sprayed to the end cover or the safety valve.

In one embodiment, the fire extinguishing device housing includes a sealing film layer and a first supporting film layer. The sealing film layer surrounds and forms the sealing space. The first support film layer covers the surface of the sealing film layer away from the fire extinguishing agent. The first support film layer is used to be disposed on a plurality of the end caps or a plurality of the safety valves.

In one embodiment, the fire extinguishing device housing further includes a second support layer. The second support layer is disposed between the sealing film layer and the first support film layer. The second support layer covers the surface of the sealing film layer away from the fire extinguishing agent.

In one embodiment, the fire extinguishing device casing includes a casing and a plurality of melt film layer structures. The casing surrounds and forms the sealed space. A plurality of the melt film layer structures are arranged on the casing at intervals. Each of the melt film layer structures is used to be arranged in a one-to-one correspondence with each of the end caps or each of the safety valves.

In one embodiment, each of the melt film layer structures includes a sealing film layer and a first supporting film layer. The sealing film layer is disposed adjacent to the fire extinguishing agent. The first supporting film layer is disposed between the sealing film layer and the end cap or the safety valve.

In one embodiment, the passive fire extinguishing device further includes a barrier protection structure. The blocking protection structure is arranged on the surface of the fire extinguishing device casing away from the end cover or the safety valve.

In one embodiment, the barrier protection structure is a carbon nanofiber braided layer structure or a glass fiber braided layer structure.

In one embodiment, the braided pore size of the carbon nanofiber braided layer structure is 300 microns to 2000 microns.

In one embodiment, the braided pore size of the glass fiber braided layer structure ranges from 300 microns to 2000 microns.

In one embodiment, the barrier protection structure includes a first barrier layer, a second barrier layer and a third barrier layer.

In one embodiment, the first barrier layer is disposed on the surface of the fire extinguishing device housing away from the end cover or the safety valve, and the second barrier layer is disposed away from the first barrier layer On the surface of the fire extinguishing device housing, the third barrier layer is disposed on the surface of the second barrier layer away from the first barrier layer.

In one embodiment, each of the melt film layer structures further includes: a second support layer disposed between the sealing film layer and the first support film layer.

In one embodiment, the casing of the fire extinguishing device is provided with a charging port for charging and discharging the fire extinguishing agent and the compressed gas.

In one embodiment, a battery pack is provided. The battery pack includes a battery pack box, a plurality of battery modules and a fire extinguishing device casing. The battery pack box is surrounded to form a battery placement space. A plurality of the battery modules are arranged in the battery placement space at intervals. The fire extinguishing device casing is arranged in the battery placement space. And the fire extinguishing device casing is disposed between the end covers of the plurality of battery modules and the battery pack box. The casing of the fire extinguishing device is surrounded to form a sealed space. A fire extinguishing agent and a compressed gas are arranged in the sealed space, which is used for fire extinguishing in the event of thermal runaway of the battery.

In one embodiment, the battery pack further includes the blocking protection structure, and the blocking protection structure is disposed between the casing of the fire extinguishing device and the battery pack box.

In one embodiment, the battery pack further includes a battery pack pressure relief valve, and the battery pack pressure relief valve is disposed in the battery pack case.

In the above-mentioned fire extinguishing device and battery pack, the fire extinguishing device casing is provided on the end covers of the plurality of battery modules. Alternatively, the fire extinguishing device housing may be provided in the safety valves of a plurality of the battery cells. When thermal runaway occurs in the battery cells, the high-temperature and high-speed fluid sprayed from the end caps of the battery modules (or the safety valves of the battery cells) causes thermal shock and force shock to the casing of the fire extinguishing device. At this time, the mechanical strength of the fire extinguishing device casing at the position corresponding to the end cover of the battery module (or the safety valve of the battery cell) decreases and is torn. The casing of the fire extinguishing device is damaged or melted to form a crack (melt mouth).

The fire extinguishing agent will be ejected from the crack, and enter the interior of the thermally runaway battery module (or battery cell) through the end cap (or safety valve), and cover the surface of the thermally runaway battery cell. Furthermore, the fire extinguishing agent sprayed from the casing of the fire extinguishing device will physically cool the thermally runaway battery cells and the exhaust gas. In addition, the fire extinguishing agent will endothermically decompose to cool the gas phase, and chemically flame retardant to interrupt the free radical chain reaction. At the same time, the inert gas generated by the volatilization of the fire extinguishing agent and the decomposition of the fire extinguishing agent can dilute the thermally runaway combustible vent gas.

Therefore, the casing of the fire extinguishing device is arranged on the end caps (or safety valves) of a plurality of battery modules (or battery cells), and the fire extinguishing agent can be sprayed to the end caps or the safety valve in time. The thermally runaway battery module (or battery cell) is cold-extracted by the fire extinguishing agent sprayed from the casing of the fire extinguishing device, and the gas released by the thermally runaway battery cell is chemically flame retardant. At this time, through the passive fire extinguishing device, the entire process from the thermal runaway of the battery cell to the fire extinguishing by the fire extinguishing agent belongs to a passive triggering process and does not require a control system. In addition, the passive fire extinguishing device can perform fire extinguishing in a timely manner, and the fire extinguishing time is very short, thereby improving the fire extinguishing efficiency. At the same time, the casing of the fire extinguishing device is arranged at the position of the end caps of the plurality of battery modules or the safety valves of the plurality of battery cells, and the corresponding position of the casing of the fire extinguishing device will be triggered in time after the thermal runaway of the battery cells occurs. The fire extinguishing agent is released to extinguish the fire, the thermal runaway battery can be accurately located, and the cooling effect is high.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or in the traditional technology, the following briefly introduces the accompanying drawings that are used in the description of the embodiments or the traditional technology. Obviously, the drawings in the following description are only the For some embodiments of the application, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a passive fire extinguishing device in an embodiment provided by the application.

FIG. 2 is a schematic structural diagram of a casing of a fire extinguishing device in an embodiment provided by the present application.

FIG. 3 is a schematic structural diagram of a casing of a fire extinguishing device in an embodiment provided by the present application.

FIG. 4 is a schematic structural diagram of a casing of a fire extinguishing device in an embodiment provided by the present application.

FIG. 5 is a schematic structural diagram of a casing of a fire extinguishing device in an embodiment provided by the present application.

FIG. 6 is a schematic structural diagram of a passive fire extinguishing device in an embodiment provided by the present application.

FIG. 7 is a partial structural schematic diagram of the barrier protection structure and the fire extinguishing device casing shown in FIG. 6 provided by the present application.

FIG. 8 is a schematic structural diagram of a barrier protection structure in an embodiment provided by the present application.

Description of reference numbers:

Passive fire extinguishing device 100, fire extinguishing device casing 10, fire extinguishing agent 110, first crack 121, second crack 122, first supporting film layer 131, second supporting layer 132, sealing film layer 133, shell 134, melting film layer Structure 130, filling port 140, barrier protection structure 20, first barrier layer 210, second barrier layer 220, third barrier layer 230, normal battery module 310, thermal runaway battery module 320, end cap 330, battery pack 40. The battery pack pressure relief valve 410 and the battery pack box 420.

detailed description

In order to make the above objects, features and advantages of the present application more clearly understood, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", " Back, Left, Right, Vertical, Horizontal, Top, Bottom, Inner, Outer, Clockwise, Counterclockwise, Axial , "radial", "circumferential" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the application and simplifying the description, rather than indicating or implying the indicated device or Elements must have a particular orientation, be constructed and operate in a particular orientation and are therefore not to be construed as limitations on this application.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

In this application, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between the two elements, unless otherwise specified limit. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

In this application, unless otherwise expressly stated and defined, a first feature "on" or "under" a second feature may be in direct contact with the first and second features, or the first and second features indirectly through an intermediary get in touch with. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or an intervening element may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for the purpose of illustration only and do not represent the only embodiment.

Please refer to FIG. 1 . FIG. 1 is a schematic structural diagram of a passive fire extinguishing device 100 according to an embodiment of the present application. The passive fire extinguishing device 100 is applied to the battery pack 40 for fire extinguishing. The battery pack 40 includes a battery module 310 . The battery module 310 includes a plurality of battery cells (not shown). The battery cell is provided with a safety valve. The battery module 310 has an end cap 330 .

The passive fire extinguishing device 100 includes a fire extinguishing device housing 10 . The fire-extinguishing device casing 10 surrounds and forms a sealed space. A fire extinguishing agent 110 and compressed gas are arranged in the sealed space. The fire extinguishing device housing 10 is configured to be disposed at the end caps 330 of the plurality of battery modules 310 or the safety valves of the plurality of battery cells. When the thermal runaway of the battery cell occurs, the end cover 330 or the safety valve is opened, the casing 10 of the fire extinguishing device is ruptured, and the fire extinguishing agent is sprayed to the end cover 330 or the safety valve 110. In one embodiment, the fire extinguishing agent 110 may be a liquid fire extinguishing agent, such as a water-based fire extinguishing agent, perfluorohexanone or granular sodium polyacrylate hydrogel, and the like. The compressed gas can be a high-pressure inert gas such as nitrogen, carbon dioxide, and argon, and can also be understood as a gas with power. The compressed gas can push the fire extinguishing agent 110 to spray outward. The pressure of the sealed space surrounded and formed by the fire extinguishing device casing 10 is set to the rated punching pressure. The rated stamping pressure can be 0.3Mpa to 6Mpapa to adapt to low and medium pressure conditions.

The fire extinguishing device casing 10 is disposed on the end covers 330 of the plurality of battery modules 310 . Alternatively, the fire extinguishing device casing 10 may be provided in the safety valves of a plurality of the battery cells. It can be understood that the reference numeral 310 in FIG. 1 may represent a battery module or a battery cell. As shown in FIG. 1 , the battery modules (or battery cells) that do not normally have thermal runaway are marked as normal battery modules 310 , and the battery modules (or battery cells) that have thermal runaways are marked as thermal runaway battery modules 320 . When thermal runaway occurs in the battery cells, the high-temperature and high-speed fluid injected from the end caps 330 of the thermally runaway battery modules 320 (or the safety valve of the battery cells) causes thermal shock and force shock to the fire extinguishing device casing 10 . At this time, the mechanical strength of the fire extinguishing device casing 10 (the positions shown in the

reference numerals

121 and 121 in FIG. 1 ) corresponding to the end cover 330 of the thermally runaway battery module 320 (or the safety valve of the battery cell) is reduced. and torn apart. The casing 10 of the fire extinguishing device is damaged or melted to form a first crack 121 and a second crack 122 .

Furthermore, the fire extinguishing device housing 10 is provided with compressed gas and a rated ram pressure. The fire extinguishing agent 110 will be ejected from the cracks (the first crack 121 and the second crack 122 in FIG. 1 ), and enter the thermal runaway battery module (or battery cell) 320 through the end cap (or safety valve) 330 . Inside, and cover the surface of the thermal runaway battery cell. Furthermore, the fire extinguishing agent 110 sprayed from the fire extinguishing device casing 10 will physically cool the thermally runaway battery cells and the gas released by them. Specifically, the fire extinguishing agent 110 will endothermically decompose to cool the gas phase, and chemically flame retardant to interrupt the free radical chain reaction. At the same time, the inert gas generated by the volatilization of the fire extinguishing agent 110 and the decomposition of the fire extinguishing agent can dilute the flammable vent gas generated by thermal runaway.

Therefore, the fire extinguishing device housing 10 is disposed on the end caps (or safety valves) 330 of a plurality of battery modules (or battery cells) 310, and the fire extinguishing can be sprayed to the end caps or the safety valves in time Agent 110. The thermal runaway battery module (or battery cell) 320 is cold-extracted by the fire extinguishing agent 110 sprayed from the fire extinguishing device housing 10 , and the thermal runaway battery module (or battery cell) 320 is released. The gas is chemically flame retardant. At this time, by setting the passive fire extinguishing device 100, the entire process from the thermal runaway of the battery cell to the fire extinguishing process by the fire extinguishing agent 110 is a passive triggering process and does not require a control system. In addition, the passive fire extinguishing device 100 can perform fire extinguishing in a timely manner, and the fire extinguishing time is very short, thereby improving the fire extinguishing efficiency. At the same time, the fire extinguishing device casing 10 is disposed at the position of the end caps 330 of the plurality of battery modules 310 or the safety valve positions of the plurality of battery cells, and the fire extinguishing device casing 10 will be triggered in time after the thermal runaway of the battery cells occurs. The part corresponding to the end cover 330 or the safety valve of the 100°C makes the passive fire extinguishing device 100 release the fire extinguishing agent 110 for fire extinguishing, so that the thermal runaway battery can be precisely located, and the cooling effect is high.

Please refer to FIG. 2 , which is a schematic structural diagram of a casing 10 of a fire extinguishing device according to an embodiment of the present application. The fire extinguishing device housing 10 includes a sealing film layer 133 and a first supporting film layer 131 . The sealing film layer 133 surrounds the sealing space. The first supporting film layer 131 covers the surface of the sealing film layer 133 away from the fire extinguishing agent 110 . The first support film layer 131 is used to be disposed on a plurality of the end caps 330 or a plurality of the safety valves.

In this embodiment, the sealing film layer 133 may be aluminum foil, tin foil, copper foil, or the like. The first supporting film layer 131 may be a polymer material such as PE, PC, etc., a plastic film. At this time, the melting point of the first supporting film layer 131 is in the range of 70°C to 110°C, and the melting point can also be set in other ranges as required. When the thermal runaway of the battery cell occurs, the high-temperature and high-speed fluid injected from the end cap 330 of the thermally runaway battery module 320 (or the safety valve of the battery cell) makes the sealing film layer 133 and the first supporting film layer 131 It is melted to form corresponding cracks (melts), such as the first crack 121 and the second crack 122 in FIG. 1 .

The sealing film layer 133 surrounds the sealing space. The sealed space is used for placing the fire extinguishing agent 110 . By wrapping the fire extinguishing agent 110 with the sealing film layer 133 , the leakage of the fire extinguishing agent 110 can be prevented. The first supporting film layer 131 covers the sealing film layer 133, which supports the fire extinguishing agent 110, and can prevent the high pressure gas from bursting the fire extinguishing device casing 10, thereby preventing the fire extinguishing. The device housing 10 plays a protective and supporting role as a whole. Therefore, when the battery cells are normal, the sealing film layer 133 and the first supporting film layer 131 can ensure that the fire extinguishing agent 110 does not leak.

In addition, the first support film layer 131 is disposed on a plurality of the end caps (or safety valves) 330 . When the thermal runaway of the battery cell occurs, after the end cover 330 or the safety valve is opened, the high temperature and high velocity fluid can directly and quickly break through the fire extinguishing device casing 10 . Furthermore, the fire extinguishing agent 110 is sprayed from the fire extinguishing device casing 10 and sprayed to the end cover (or the safety valve) 330 to quickly and promptly extinguish the fire.

In one embodiment, the thickness of the sealing film layer 133 may be between 0 mm and 1 mm. The thickness of the first support film layer 131 may be between 0 mm and 2 mm. The thickness of the first supporting film layer 131 is greater than the thickness of the sealing film layer 133 . The thickness of the sealing film layer 133 and the thickness of the first supporting film layer 131 may facilitate the spraying of the fire extinguishing agent 110 from the inside of the fire extinguishing device casing 10 . In addition, the first supporting film layer 131 and the sealing film layer 133 can play the role of protecting and supporting the fire extinguishing agent 110, so as to avoid the leakage of the battery cells when they are normal.

Please refer to FIG. 3 , which is a schematic structural diagram of a casing 10 of a fire extinguishing device according to an embodiment of the application. In one embodiment, the fire extinguishing device housing 10 not only includes the first supporting film layer 131 and the sealing film layer 133 , but also includes a second supporting layer 132 . The second support layer 132 is disposed between the sealing film layer 133 and the first support film layer 131 . The second support layer 132 covers the surface of the sealing film layer 133 away from the fire extinguishing agent 110 .

In this embodiment, the second support layer 132 covers the sealing film layer 133 . The first support film layer 131 covers the second support layer 132 . The first supporting film layer 131 , the second supporting layer 132 and the sealing film layer 133 form the fire extinguishing device casing 10 . The second support layer 132 may be a composite braided layer. The composite braided layer can be a composite film layer formed of aluminum foil, tin foil, copper foil, etc. and polymer materials such as PE and PC. In one embodiment, the composite braided layer is an aluminum-plastic film formed by a composite of aluminum foil and plastic film.

In this embodiment, the second support layer 132 has both the characteristics of the sealing film layer 133 and the characteristics of the first support film layer 131, so that the fire extinguishing agent 110 can be prevented from leaking , and can play a supporting role. When the second support layer 132 is a composite braided layer and is disposed between the sealing film layer 133 and the first support film layer 131 , the second support layer 132 can be better separated from the The sealing film layer 133 and the first supporting film layer 131 are adhered and combined.

Please refer to FIG. 4 , which is a schematic structural diagram of a casing 10 of a fire extinguishing device according to an embodiment of the present application. In one embodiment, the fire extinguishing device casing 10 includes a casing 134 and a plurality of melt film layer structures 130 . The casing 134 surrounds the sealed space. A plurality of the melt film layer structures 130 are disposed on the casing 134 at intervals. Each of the melt film layer structures 130 is used to be arranged in a one-to-one correspondence with each of the end caps 330 or each of the safety valves.

In this embodiment, the casing 134 may be made of materials with high melting points such as copper or iron. A plurality of the melt film layer structures 130 are arranged in the casing 134 at intervals, which can be understood as: the casing 134 and the plurality of the melt film layer structures 130 are surrounded to form the sealed space, and the sealed space is formed by where the fire extinguishing agent 110 is placed. Each of the melt film layer structures 130 is arranged in a one-to-one correspondence with each of the end caps (or the safety valve) 330 . When thermal runaway occurs in the battery cells, the high-temperature and high-speed fluid sprayed from the end caps 330 of the thermally runaway battery modules 320 (or the safety valve of the battery cells) directly impacts the melt film layer structure 130 with thermal shock and force. At this time, a crack (or called a melting point) is formed at the position of the melt film layer structure 130 . In addition, since one of the melt film layer structures 130 is disposed corresponding to one of the end caps (or the safety valve) 330, the fire extinguishing agent 110 in the fire extinguishing device casing 10 can be directly sprayed to the end The cover (or the safety valve) 330 can be more targeted for fire extinguishing, and the thermal runaway battery can be accurately positioned without a complex control system, and the cooling effect is high.

In addition, the casing 134 is provided at the position of the fire extinguishing device casing 10 except for the position corresponding to the end cover (or the safety valve) 330 . The casing 134 can support the entire fire extinguishing device casing 10 , and can seal and prevent leakage of the fire extinguishing agent 110 . The casing 134 may be a structure with high rigidity and rigidity, so that problems such as leakage of fire extinguishing agent caused by friction with the casing 10 of the fire extinguishing device can be avoided during the running of the vehicle. In addition, the housing 134 can be fixed with the battery pack box to stabilize the fire extinguishing device housing 10 and prevent position deviation. Furthermore, the fire extinguishing agent 110 can be sprayed to the end cover (or the safety valve) 330 more accurately through the melt film layer structure 130 to achieve fire extinguishing.

In one embodiment, each of the melt film layer structures 130 includes a sealing film layer 133 and a first supporting film layer 131 . The sealing film layer 133 is disposed close to the fire extinguishing agent 110 . The first supporting film layer 131 is disposed between the sealing film layer 133 and the end cap 330 or the safety valve.

In this embodiment, the sealing film layer 133 may be aluminum foil, tin foil, copper foil, or the like. The first supporting film layer 131 may be a polymer material such as PE, PC, etc., a plastic film. The melting point of the first support film layer 131 is in the range of 70° C. to 110° C., and the melting point can also be set in other ranges as required. When the thermal runaway of the battery cell occurs, the high-temperature and high-speed fluid injected from the end cap 330 of the thermally runaway battery module 320 (or the safety valve of the battery cell) makes the sealing film layer 133 and the first supporting film layer 131 Broken to form a corresponding crack (melt mouth). Therefore, when the thermal runaway occurs in the battery cell, after the end cap (or the safety valve) 330 is opened, the melt film layer structure 130 can be directly and quickly broken, so that the fire extinguishing agent 110 is sprayed towards the end The cover (or the safety valve) 330 can be put out in time and quickly.

Please refer to FIG. 5 , which is a schematic structural diagram of a casing 10 of a fire extinguishing device according to an embodiment of the present application. Each of the melt film layer structures 130 not only includes a sealing film layer 133 and a first support film layer 131 , but also includes a second support layer 132 . The second support layer 132 is disposed between the sealing film layer 133 and the first support film layer 131 .

In one embodiment, the second support layer 132 may be a composite braided layer. The composite braided layer can be a composite film layer formed of aluminum foil, tin foil, copper foil, etc. and polymer materials such as PE and PC. In one embodiment, the composite film layer is an aluminum-plastic film formed by a composite of aluminum foil and plastic. The second support layer 132 has both the characteristics of the sealing film layer 133 and the characteristics of the first support film layer 131, so that the fire extinguishing agent 110 can be prevented from leaking, and support. In addition, the second support layer 132 can be better bonded to the sealing film layer 133 and the first support film layer 131 respectively.

Please refer to FIG. 6 and FIG. 7 . FIG. 6 is a schematic structural diagram of a casing 10 of a fire extinguishing device according to an embodiment of the present application. FIG. 7 is a partial structural schematic diagram of the relative positions of the fire extinguishing device casing 10 , the blocking protection structure 20 and the end cover 330 (or the safety valve) in an embodiment of the present application. In one embodiment, the passive fire extinguishing device 100 further includes a barrier protection structure 20 . The blocking protection structure 20 is disposed on the surface of the fire extinguishing device casing 10 away from the end cover 330 or the safety valve.

In this embodiment, the blocking protection structure 20 is disposed on the surface of the fire extinguishing device casing 10 away from the end cover 330 or the safety valve, which can support and protect the fire extinguishing device casing 10 . fixed role. During the driving process of the vehicle, the blocking protection structure 20 can reduce the wear of the fire extinguishing device casing 10 caused by ground vibration, and at the same time play a fixing role on the fire extinguishing device casing 10 to prevent the fire extinguishing device casing 10 from sliding. .

In one embodiment, the barrier protection structure 20 may be a fiber layer, asbestos, or glass fiber, or the like. In one embodiment, the barrier protection structure 20 may be a fiber layer woven from carbon nanofibers or glass fibers. When the thermal runaway of the lithium battery occurs in the battery cell, the gas released during the thermal runaway can be filtered through the fiber layer, high-energy solid particles can be retained in the fiber layer, and the temperature of the released gas can be further reduced. At the same time, the high-energy solid particles are retained in the fiber layer through the fiber layer, which can avoid the high-energy solid particles being released into the air and causing pollution.

In one embodiment, the barrier protection structure 20 is a carbon nanofiber braided layer structure or a glass fiber braided layer structure. The braided pore size of the carbon nanofiber braided layer structure is 300 microns to 2000 microns. Alternatively, the braided pore size of the glass fiber braided layer structure is 300 microns to 2000 microns.

In this embodiment, through the weaving pore size of the carbon nanofiber woven layer structure, or setting the woven pore size of the glass fiber woven layer structure to 300 microns to 2000 microns, the gas released during thermal runaway can be filtered, The high-energy solid particles are retained in the barrier protection structure 20 . In addition, when the thermal runaway of the battery cell occurs, the blocking protection structure 20 covers the surface of the end cap 330 (or the safety valve), which can isolate the eruption from the air and prevent the flammable mixed gas, The sparks are in contact with the air, reducing the conditions for a fire to burn.

In one embodiment, the blocking protection structure 20 and the fire extinguishing device casing 10 are fixed by means of bonding. The fire extinguishing device casing 10 is supported and fixed by the blocking protection structure 20 .

Please refer to FIG. 8 , which is a schematic structural diagram of the blocking protection structure 20 in an embodiment of the present application. In one embodiment, the barrier protection structure 20 includes a first barrier layer 210 , a second barrier layer 220 and a third barrier layer 230 . The first barrier layer 210 is disposed on the surface of the fire extinguishing device casing 10 away from the end cover (or safety valve) 330 . The second barrier layer 220 is disposed on the surface of the first barrier layer 210 away from the casing 10 of the fire extinguishing device. The third barrier layer 230 is disposed on the surface of the second barrier layer 220 away from the first barrier layer 210 . At this time, the third barrier layer 230 is in contact with the battery pack case 420 . The first blocking layer 210 can block the flame generated by the mixture of combustible gas such as methane, hydrogen, acetylene and oxygen in the eruption gas caused by thermal runaway. The second barrier layer 220 can fix and absorb the high-energy solid particles in the spray caused by thermal runaway. The third barrier layer 230 can filter dust particles. Therefore, through the first barrier layer 210 , the second barrier layer 220 and the third barrier layer 230 in the barrier protection structure 20 , the eruption caused by the thermal runaway can be treated by multiple layers. control, and thus play a multi-protective role. Wherein, the first barrier layer 210 , the second barrier layer 220 and the third barrier layer 230 may be fiber layers, asbestos, glass fibers, or the like. According to the functional characteristics of each barrier layer, the pore size of the barrier layer can be differently defined to realize the function of each layer.

In one embodiment, the fire extinguishing device casing 10 is provided with a filling port 140 for charging and discharging the fire extinguishing agent 110 and the compressed gas.

In this embodiment, an appropriate amount of fire extinguishing agent 110, taking perfluorohexanone as an example, is filled into the sealed space surrounded by the casing 10 of the fire extinguishing device through the filling port 140. Specifically, the sealed space is evacuated through the filling port 140, and high-pressure inert gas is injected into the sealed space. Taking N ₂ as an example, this process can be repeated about 2-3 times. Vacuum again, fill an appropriate amount of liquid fire extinguishing agent (perfluorohexanone) into the sealed space through the filling port 140, and fill with nitrogen to the rated filling pressure. Finally, the filling port 140 is sealed.

Therefore, the passive fire extinguishing device 100 has a simple structure, can realize fire extinguishing of thermally runaway battery cells without an auxiliary control system, fluid flow pipeline and valve body, and is low in cost and easy to arrange.

An embodiment of the present application provides a battery pack 40 . The battery pack 40 includes a battery pack case 420 and a plurality of battery modules 310. The battery pack box 420 is surrounded to form a battery placement space. A plurality of the battery modules 310 are disposed in the battery placement space at intervals. The fire extinguishing device housing 10 is provided in the battery placement space. The fire extinguishing device casing 10 is disposed on the end covers 330 of the plurality of battery modules 310 . The fire-extinguishing device casing 10 is surrounded to form a sealed space, and the fire-extinguishing agent 110 and the compressed gas are arranged in the sealed space for fire-extinguishing in the event of thermal runaway of the battery.

In this embodiment, the fire extinguishing device casing 10 provided with the fire extinguishing agent 110 is disposed between the battery pack box 420 and the end covers 330 of the plurality of battery modules 310 . Furthermore, when the thermal runaway of the battery occurs, the fire extinguishing agent 110 can be sprayed to the end cover 330 in time. The fire-extinguishing agent 110 sprayed from the fire-extinguishing device housing 10 can perform cold extraction on the thermally runaway battery cells in the thermally runaway battery module, and chemically flame retardant the gas released by the thermally runaway battery cells. At this time, through the passive fire extinguishing device 100, the entire process from the thermal runaway of the battery cell to the use of the fire extinguishing agent 110 to extinguish the fire belongs to a passive triggering process and does not require a control system. At the same time, the fire extinguishing device casing 10 is disposed at the position of the end caps 330 of the plurality of battery modules 310 , and the corresponding position of the fire extinguishing device casing 10 will be triggered in time after the thermal runaway of the battery cells occurs, releasing all the The fire extinguishing agent 110 is used to extinguish the fire, so that the thermal runaway battery can be accurately located, and the cooling effect is high.

In one embodiment, the battery pack 40 further includes the barrier protection structure 20 , and the barrier protection structure 20 is disposed between the fire extinguishing device casing 10 and the battery pack case 420 . The blocking protection structure 20 can play the role of supporting, protecting and fixing the fire extinguishing device casing 10 . In addition, during the driving process of the vehicle, the blocking protection structure 20 can reduce the abrasion of the fire extinguishing device casing 10 caused by ground vibration, and at the same time play a fixed role on the fire extinguishing device casing 10 to prevent the fire extinguishing device casing from being damaged. 10 swipes.

In addition, when a battery cell such as a lithium battery is thermally out of control, the barrier protection structure 20 can filter the gas released during the thermal runaway, and retain high-energy solid particles in the fiber layer, further reducing leakage. temperature of the gas. At the same time, the high-energy solid particles are retained in the fiber layer by the blocking protection structure 20, which can prevent the high-energy solid particles from being released into the air to cause pollution.

In one embodiment, the battery pack 40 further includes a battery pack pressure relief valve 410 . The battery pack pressure relief valve 410 is disposed on the battery pack box body 420 and is disposed close to the barrier protection structure 20 (fiber layer).

In one embodiment, the battery pack 40 includes the passive fire extinguishing device 100 described in any one of the foregoing embodiments. The features of the above multiple embodiments can be combined with each other to achieve fire extinguishing.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present application, and the descriptions thereof are more specific and detailed, but should not be construed as a limitation on the scope of the patent application. It should be pointed out that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the appended claims.

Claims

A passive fire extinguishing device is applied to a battery pack, the battery includes a battery module, the battery module includes a plurality of battery cells, the battery cells are provided with a safety valve, and the battery module has an end cover, It is characterized in that, the passive fire extinguishing device comprises:

The shell of the fire extinguishing device is surrounded to form a sealed space, and the fire extinguishing agent and the compressed gas are arranged in the sealed space;

Wherein, the fire extinguishing device casing is used to be arranged on the end caps of a plurality of battery modules or the safety valves of a plurality of battery cells;

When thermal runaway of the battery cell occurs, the end cover or the safety valve is opened, the casing of the fire extinguishing device is ruptured, and the fire extinguishing agent is sprayed to the end cover or the safety valve.
The passive fire extinguishing device according to claim 1, wherein the casing of the fire extinguishing device comprises:

a sealing film layer, surrounding and forming the sealing space;

The first supporting film layer is coated on the surface of the sealing film layer away from the fire extinguishing agent, and the first supporting film layer is used to be disposed on the plurality of end caps or the plurality of safety valves.
The passive fire extinguishing device according to claim 2, wherein the casing of the fire extinguishing device further comprises a second supporting layer, and the second supporting layer is arranged between the sealing film layer and the first supporting film layer. and cover the surface of the sealing film layer away from the fire extinguishing agent.
The passive fire extinguishing device according to claim 1, wherein the casing of the fire extinguishing device comprises:

a shell, surrounding and forming the sealed space;

A plurality of melt film layer structures are arranged on the casing at intervals;

Each of the melt film layer structures is used to be arranged in a one-to-one correspondence with each of the end caps or each of the safety valves.
The passive fire extinguishing device according to claim 4, wherein each of the melt film layer structures comprises:

a sealing film layer, arranged close to the fire extinguishing agent;

The first supporting film layer is arranged between the sealing film layer and the end cap or the safety valve.
The passive fire extinguishing device according to claim 1, wherein the passive fire extinguishing device further comprises:

The blocking protection structure is arranged on the surface of the fire extinguishing device casing away from the end cover or the safety valve.
The passive fire extinguishing device according to claim 6, wherein the barrier protection structure is a carbon nanofiber braided layer structure or a glass fiber braided layer structure.
The passive fire extinguishing device according to claim 7, wherein the woven pore size of the carbon nanofiber woven layer structure is 300 microns to 2000 microns.
The passive fire extinguishing device according to claim 7, characterized in that, the weaving pore size of the glass fiber braided layer structure is 300 microns to 2000 microns.
The passive fire extinguishing device according to claim 6, wherein the barrier protection structure comprises a first barrier layer, a second barrier layer and a third barrier layer.
The passive fire extinguishing device according to claim 10, wherein the first barrier layer is provided on the surface of the fire extinguishing device housing away from the end cover or the safety valve, and the second barrier layer is provided On the surface of the first barrier layer away from the casing of the fire extinguishing device, the third barrier layer is disposed on the surface of the second barrier layer away from the first barrier layer.
The passive fire extinguishing device according to claim 5, wherein each of the molten film layer structures further comprises:

The second support layer is disposed between the sealing film layer and the first support film layer.
The passive fire extinguishing device according to claim 1, wherein the casing of the fire extinguishing device is provided with a filling port for charging and discharging the fire extinguishing agent and the compressed gas.
A battery pack, comprising:

The battery pack box is surrounded to form a battery placement space;

a plurality of battery modules, arranged at intervals in the battery placement space;

The fire extinguishing device casing is arranged in the battery placement space, and the fire extinguishing device casing is arranged between the end covers of the plurality of battery modules and the battery pack box;

The casing of the fire extinguishing device is surrounded to form a sealed space, and the sealed space is provided with fire extinguishing agent and compressed gas, which is used for fire extinguishing when the battery is thermally out of control.
The battery pack according to claim 14, wherein the battery pack further comprises the barrier protection structure, and the barrier protection structure is disposed between the fire extinguishing device casing and the battery pack box.
The battery pack according to claim 14, wherein the battery pack further comprises a battery pack pressure relief valve, and the battery pack pressure relief valve is disposed in the battery pack case.