Safety-enhanced battery module

Abstract

A battery module according to one aspect of the present invention includes: a cell assembly having a plurality of stacked battery cells; a module case that houses the cell assembly in an internal space and has a vent hole formed therein; and a cover member that has a plurality of spaced-apart fire-resistant layers, each having a discharge hole formed therein, and is coupled to an outer surface of the module case so that the vent hole and the discharge hole communicate with each other; and the discharge hole of one of the fire-resistant layers and the discharge hole of the other opposite fire-resistant layer may be arranged so as not to overlap each other.

Description

[Technical Field]

[0001] The present invention relates to a battery module, and more specifically, to a battery module that has a one-way vent structure provided in a double layer of fire-resistant material on the top of the module, which allows gas generated inside the module to be easily discharged while preventing re-entry into adjacent modules, thereby preventing chain fires and explosions.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0031432, filed on March 9, 2023, the entire contents of which are incorporated herein by reference in their entirety in the specification and drawings thereof. [Background technology]

[0003] Semi-permanent batteries that convert electrical energy into a form of chemical energy and can be repeatedly charged and discharged are called secondary batteries to distinguish them from disposable primary batteries that cannot be reused after a single use.

[0004] Secondary batteries include lithium secondary batteries, nickel-cadmium (Ni-Cd) batteries, lead-acid batteries, nickel-metal hydride (Ni-MH) batteries, zinc-air batteries, alkaline manganese batteries, etc. Lead-acid batteries and lithium secondary batteries are the most widely commercialized secondary batteries.

[0005] In particular, lithium secondary batteries have recently been widely used as batteries for electric vehicles due to their high energy storage density, ability to be lightweight and compact, excellent safety, low discharge rate, and long life.For reference, lithium secondary batteries are generally classified into cylindrical, prismatic, and pouch types depending on their manufacturing form, and their uses are diverse, including batteries for energy storage systems (ESS) and other electrical devices in addition to electric vehicle batteries.

[0006] Currently, the operating voltage of one lithium secondary battery cell is approximately 2.5 V to 4.5 V. Therefore, in order to use a secondary battery as an energy source for an electric vehicle, a battery module is formed by connecting multiple lithium ion secondary battery cells in series and / or parallel, and a battery pack is formed by connecting the battery modules in series and / or parallel.

[0007] On the other hand, secondary batteries undergo chemical reactions during charging and discharging, so their performance may deteriorate if they are used in environments higher than the appropriate temperature, and there is a risk of unexpected fire or explosion if thermal control is not performed to maintain the appropriate temperature. Furthermore, because battery modules are structured so that these secondary batteries are housed together inside a module housing, if thermal runaway occurs in any one secondary battery and it becomes a trigger cell, the heat and flames will quickly spread to the surrounding secondary batteries, making it even easier for chain fires to occur among the secondary batteries.

[0008] In particular, in terms of integration, the battery pack must accommodate as many battery modules as possible within a limited space, and therefore, there is not enough free space inside the battery pack. For example, in a battery pack including one or more battery modules, the space between the module case and the pack case may be very narrow.

[0009] Therefore, it is necessary to quickly exhaust the vent gas even in such a narrow space, and to prevent the exhausted vent gas from flowing into other modules, thereby delaying or suppressing thermal propagation (TP). Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a battery module having an improved structure that can release internal pressure by discharging vent gas generated inside the battery module and prevent the inflow of flames or the like discharged from other surrounding battery modules.

[0011] The technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention given below. [Means for solving the problem]

[0012] A battery module according to one aspect of the present invention includes: a cell assembly having a plurality of stacked battery cells; a module case that houses the cell assembly in an internal space and has a vent hole formed therein; and a cover member that has a plurality of spaced-apart fire-resistant layers, each having a discharge hole formed therein, and is coupled to an outer surface of the module case so that the vent hole and the discharge hole communicate with each other; and the discharge hole of one of the fire-resistant layers and the discharge hole of the other opposite fire-resistant layer may be arranged so as not to overlap each other.

[0013] The fire-resistant layer may be two layers, and may include a first fire-resistant layer having a first discharge hole formed therein and a second fire-resistant layer having a second discharge hole formed therein.

[0014] The cover member may further include a gap member provided between the first fire-resistant layer and the second fire-resistant layer to separate the first fire-resistant layer and the second fire-resistant layer by an amount corresponding to a predetermined gap.

[0015] The second fire-resistant layer may be provided on the first fire-resistant layer, and the first discharge hole and the second discharge hole may be in communication with each other.

[0016] At least one of the first fire-resistant layer and the second fire-resistant layer may be provided with a plurality of guide members arranged between the first exhaust hole and the second exhaust hole to guide the exhaust of vent gas generated in the module case.

[0017] The guide member may be provided in an inclined shape so as to widen in the direction in which the vent gas is discharged.

[0018] The cover member may further include a base layer and a fire-resistant coating layer that is provided over the entire area of the plate surface of the base layer and that is coated with a fire-resistant coating material that is desorbed by the pressure of vent gas when vent gas is generated inside the module case.

[0019] The base layer may be disposed between a top surface of the module case and the first fire-resistant layer.

[0020] The base layer may include at least one mesh plate having a large number of mesh lines and voids, and a support frame disposed around the periphery of the mesh plate to support the mesh plate.

[0021] The fire-resistant coating layer may be provided such that the fire-resistant coating material is bonded to the mesh wire to shield the gap.

[0022] The fire-resistant coating layer may include one or more inorganic materials selected from ceramic, silicon, silica aerogel, and silica-based inorganic fibers.

[0023] The particle size of the inorganic material may be formed to be relatively smaller than the voids.

[0024] According to another aspect of the present invention, a battery pack may be provided that includes one or more of the battery modules described above. [Effects of the Invention]

[0025] According to one aspect of the present invention, even if the space between the battery module and the pack case is narrow when the battery module is housed inside the pack case, the vent gas is discharged through a staggered vent gas discharge path provided between the double fire-resistant layers, thereby effectively preventing heat accumulation and thermal explosion of the battery module.

[0026] In addition, according to one aspect of the present invention, the staggered exhaust path can prevent vent gas or foreign matter discharged from a module from flowing into adjacent battery modules, thereby minimizing the risk of chain fire or thermal runaway in healthy battery cells or battery modules due to vent gas or flames.

[0027] Additionally, a double fireproof layer is placed on top of the module to minimize heat transfer to surrounding modules and the resulting thermal runaway.

[0028] Furthermore, since there is no need to form a gap or space (an open space in an existing lid or the like) for opening a separate vent hole, a decrease in the energy density of the battery pack can be prevented.

[0029] The drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further understand the technical concepts of the present invention as well as the content of the invention, and therefore the present invention should not be interpreted as being limited to only the matters depicted in the drawings. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a schematic perspective view of a battery module according to an embodiment of the present invention; [Figure 2] FIG. 2 is an exploded perspective view of the main components of the battery module of FIG. 1. [Figure 3] 3 is a perspective view of a first fire-resistant layer in a cover member of a battery module according to one embodiment of the present invention; FIG. [Figure 4] 1 is a perspective view of a battery module in accordance with an embodiment of the present invention, in which a second fire-resistant layer is bonded to a first fire-resistant layer; [Figure 5] 1 is a cross-sectional view of a structure of a battery pack including a battery module according to an embodiment of the present invention. [Figure 6] FIG. 6 is a partially enlarged view of FIG. 5. [Figure 7] FIG. 10 is a diagram schematically illustrating the movement and flow of vent gas on the upper surface of the battery module. [Figure 8] FIG. 10 is a diagram schematically illustrating the movement and flow of vent gas on the upper surface of the battery module. [Figure 9] FIG. 10 is a perspective view of a fire-resistant coating layer applied to a base layer and a plate surface in a battery module according to another embodiment of the present invention. [Figure 10] 10 is a view schematically illustrating a path through which vent gas is discharged through a cover member in a battery module according to another embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms and words used in the specification and claims should not be construed as being limited to their ordinary or dictionary meanings, but should be construed as having meanings and concepts corresponding to the technical ideas of the present invention, in accordance with the principle that the inventor can appropriately define the concepts of terms himself in order to best describe the invention.

[0032] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, and that there may be various equivalent and modified embodiments that can be substituted for them at the time of this application.

[0033] In the drawings, the size of each component or specific parts of the component may be slightly exaggerated, omitted, or shown schematically for ease of explanation and clarity. Therefore, the size of each component does not fully reflect the actual size. If a detailed description of related well-known functions or configurations is deemed to be likely to obscure the gist of the present invention, such detailed description will be omitted.

[0034] FIG. 1 is a schematic perspective view of a battery module according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the main components of the battery module of FIG.

[0035] 1 and 2, a battery module 10 according to one embodiment of the present invention includes a cell assembly 100, a module case 200, and a cover member 300.

[0036] The cell assembly 100 may include one or more battery cells 110. Here, each battery cell 110 may refer to a secondary battery. Referring primarily to FIG. 2 , the battery cell 110 includes an electrode assembly, a case that houses the electrode assembly, and a pair of electrode leads 112 that are connected to the electrode assembly and extend outside the case to function as electrode terminals. The pair of electrode leads 112 extend from both ends of the battery cell 110, i.e., in the longitudinal direction.

[0037] If necessary, the battery cell 110 may have a form in which the electrode lead 112 is located only at one end of the battery cell 110. Meanwhile, the present invention is not limited in any way by the specific type or form of the battery cell 110, and a wide variety of battery cells 110 known at the time of filing of the present invention can be used to configure the cell assembly 100 of the present invention. In this embodiment, a pouch-type secondary battery that has high energy density and is easy to stack is targeted, but it goes without saying that cylindrical or prismatic secondary batteries can also be used as the battery cell 110.

[0038] Such battery cells 110 may be stacked and arranged in at least one direction. In this embodiment, referring mainly to FIG. 2 , the battery cells 110 may be stacked in a shape in which they are arranged in a horizontal direction (the width direction of the battery module 10, the Y-axis direction) while standing upright in the vertical direction (the Z-axis direction).

[0039] The cell assembly 100 is an assembly of battery cells 110 formed by stacking a plurality of battery cells 110. That is, as shown in FIG. 2, the cell assembly 100 may be a collection of a plurality of pouch-type battery cells 110 stacked in one direction with their wide surfaces standing upright.

[0040] The module case 200 may have an internal space formed therein and may be configured to accommodate the battery cells 110. The module case 200 of the present embodiment may include a case body 210 and end plates 220 disposed on the front and rear surfaces of the case body 210.

[0041] The case body 210 may be formed in a rectangular tubular shape having an open end O at both ends in the longitudinal direction (X-axis direction) and a hollow structure. For example, the case body 210 may be formed in a tubular shape having an upper surface, a lower surface, a left side surface, and a right side surface, and openings formed at the front and rear ends, respectively.

[0042] Alternatively, the modular case 200 may be formed in various other shapes. For example, the case body 210 may be formed in a shape in which the left, right, and bottom plates are integrated with one another. In this case, the integrated case portion may be referred to as a U-frame. The U-frame may be formed in a tubular shape by welding a top plate to its upper surface. Alternatively, the modular case 200 may include a box-shaped lower case in which the left, right, front, and rear plates are integrated with one another, and an upper cover that closes the upper open end of the lower case.

[0043] The case body 210 may be configured to allow the battery cell 110 to be inserted into the interior along the longitudinal direction. That is, the case body 210 may be configured to allow the battery cell 110 to be inserted therein by a sliding or interference fit. Due to the interference fit, there may be little gap between the top and bottom surfaces of the case body 210 and the top and bottom ends of the battery cell 110, and there may also be little gap between both side surfaces of the case body 210 and both sides of the battery cell 110. The case body 210 may be formed of a metal material having rigidity and heat resistance to physically and chemically protect the housed battery cell 110.

[0044] The end plate 220 may be provided to face one side of the cell assembly 100 where the electrode leads 112 of the battery cells 110 are located, i.e., to prevent a portion where the electrode leads 112 are connected to a bus bar on a bus bar frame from being exposed to the outside, and may be provided to be coupled to the open end O of the case body 210. The end plate 220 may be configured, for example, to have an inner side made of an insulating material and an outer side made of a metallic material and to be fixedly coupled to the case body 210 by welding. Meanwhile, although not shown for convenience of illustration, the end plate 220 may have holes or slits partially formed therein to expose components that need to be exposed to the outside, such as the positive and negative terminals or connectors of the battery module 10.

[0045] The module case 200 configured as described above may have a vent hole H1 formed on at least one side. As indicated by H1 in FIG. 2, a plurality of vent holes H1 may be formed on the upper side of the module case 200, biased toward the left and right sides. The vent holes H1 may be configured to allow vent gas generated and ejected from the cell assemblies 100 housed in the interior space to be discharged to the exterior space of the module case 200. For example, the module case 200 may be formed in a sealed shape except for the vent hole H1. The vent hole H1 may be formed in a completely open shape so as to penetrate the module case 200 in an inward / outward direction.

[0046] In this embodiment, the vent hole H1 is circular, but a long hole formed in a longitudinal direction can also be used, and any shape can be used as long as the vent gas can be smoothly discharged.

[0047] The cover member 300 is disposed on the outer surface of the module case 200, and in this embodiment, the cover member may be provided on the upper side of the module case 200 as shown in Figures 1 and 2. As a result, the cover member may be configured to cover the vent hole H1 formed on the upper surface of the module case 200.

[0048] The cover member 300 may include a plurality of fire-resistant layers 301, 304 spaced apart from each other and having discharge holes H2, H3 formed therein, and a gap member 307 that separates the fire-resistant layers 301, 304 from each other.

[0049] The fire-resistant layers 301 and 304 may be formed to have substantially the same size as the upper surface of the battery module 10 and may be made of a fire-resistant material, such as mica, which can withstand heat generated by vent gas, flames, sparks, etc. during a thermal event and suppress thermal propagation (TP), such as propagation to adjacent modules.

[0050] Discharge holes H2 and H3 may be formed in the fire-resistant layers 301 and 304. The discharge holes H2 and H3 may be provided to communicate with the vent hole H1. That is, the vent hole H1 of the module case 200 and the discharge holes H2 and H3 formed in the fire-resistant layers 301 and 304, respectively, may be connected to each other. In this manner, the vent gas discharged through the vent hole H1 can be easily discharged from inside the module through a vent structure provided between the fire-resistant layers 301 and 304.

[0051] The plurality of fire-resistant layers 301, 304 may be arranged such that the discharge hole H2 of one of the fire-resistant layers 301 and the discharge hole H3 of the other fire-resistant layer 304 facing it do not overlap with each other. In other words, the discharge hole H2 of one of the fire-resistant layers 301 and the discharge hole H2 of the other adjacent fire-resistant layer 304 may be positioned at offset positions from each other.

[0052] This prevents vent gas or foreign matter discharged outside the module from flowing into adjacent battery modules 10. That is, the zigzag (staggered) discharge paths formed in the multiple fire-resistant layers 301, 304 minimize flow into adjacent modules. This will be described in detail in the next section explaining the cover member 300.

[0053] FIG. 3 is a perspective view of a first fire-resistant layer in a cover member of a battery module according to one embodiment of the present invention, and FIG. 4 is a perspective view of a battery module according to one embodiment of the present invention in which a second fire-resistant layer is bonded to the first fire-resistant layer.

[0054] Referring primarily to Figures 2 to 4, the cover member 300 may include a plurality of the fire-resistant layers 301, 304 and a gap member 307 provided between the fire-resistant layers 301, 304 to space the fire-resistant layers 301, 304 from each other.

[0055] Referring primarily to FIG. 2, the fire-resistant layers 301, 304 may be two layers, and may include a first fire-resistant layer 301 having a first discharge hole H2 formed therein and a second fire-resistant layer 304 having a second discharge hole H3 formed therein.

[0056] The first fire-resistant layer 301 may be disposed directly above the module case 200. A plurality of first exhaust holes H2 may be formed on a surface of the first fire-resistant layer 301 at positions corresponding to the positions of the vent holes H1, and the first exhaust holes H2 may be connected to the vent holes H1. The first fire-resistant layer 301 may primarily protect the module from heat caused by vent gases, flames, etc. generated in an adjacent module.

[0057] A plurality of guide members 340 may be provided on either the first fire-resistant layer 301 or the second fire-resistant layer 304. In this embodiment, the guide members 340 are provided on the plate surface of the first fire-resistant layer 301 for ease of explanation, but they may be provided not only on the top surface of the first fire-resistant layer 301 but also on the bottom surface of the second fire-resistant layer 304, or may be formed at the same height on the first fire-resistant layer 301 and the second fire-resistant layer 304 and connected to each other.

[0058] Referring primarily to FIGS. 3 and 4, the guide member 340 may be disposed between the first exhaust hole H2 and the second exhaust hole H3 to guide the discharge of vent gas generated in the module case 200. Specifically, the guide member 340 may be inclined to expand in the direction of the discharge of the vent gas. Referring to FIG. 3, a pair of guide members 340 may be arranged to expand along the X-axis and -X-axis directions around the first exhaust hole H2. This may guide or assist the flow of vent gas in one direction, and the operation thereof will be described later. Meanwhile, the height of the guide member 340 is configured to be substantially equal to the height of the gap member 307, thereby allowing the upper end of the guide member 340 to abut against the bottom surface of the second fire-resistant layer 304.

[0059] 2 and 4, the second fire-resistant layer 304 may be provided on the first fire-resistant layer 301. Like the first fire-resistant layer 301, the second fire-resistant layer 304 may also be made of a fire-resistant material, and is preferably made of mica.

[0060] A plurality of second discharge holes H3 may be provided on the plate surface of the second fire-resistant layer 304, and the second discharge holes H3 may be provided on a vent gas flow path connecting the first discharge holes H2 and the guide member 340. The diameter of the second discharge holes H3 may be relatively larger than the diameter of the first discharge holes H2, or alternatively, may be equal to the diameter of the first discharge holes H2, or may be relatively smaller than the diameter of the first discharge holes H2, as necessary.

[0061] The gap member 307 may be provided between the first refractory layer 301 and the second refractory layer 304 to separate the first refractory layer 301 and the second refractory layer 304 by a distance corresponding to a predetermined gap.

[0062] The gap member 307 is provided along the periphery of the first fire-resistant layer 301, and a plurality of gap members 307 may be provided in the width direction as well, as shown in Fig. 3. Such gap members 307 ensure a uniform gap across the entire plate surface between the first fire-resistant layer 301 and the second fire-resistant layer 304. In addition to this, not only the gap members 307 but also the guide members 340 may be configured to maintain the gap.

[0063] Although not shown, the gap member 307 can provide a joining position for joining the first and second fire-resistant layers 301, 304 to each other. Various joining methods, such as bolting or welding, can be used. Because the gap member 307 is provided, the first fire-resistant layer 301 and the second fire-resistant layer 304 can form a strong structure that can withstand pressure changes caused by vent gas, and structural rigidity against twisting, warping, bending, etc. can also be ensured.

[0064] The cover member 300 configured in this manner can withstand heat from vent gases, flames, sparks, etc. that occur during a thermal event, and can suppress thermal propagation (TP), such as propagation to adjacent modules.

[0065] According to this embodiment, even if the space between the battery module 10 and the pack case is narrow when the battery module 10 is housed inside the pack case, the vent gas is discharged through a staggered vent gas discharge path provided between the double fire-resistant layers, thereby effectively preventing heat accumulation and thermal explosion of the battery module 10.

[0066] In addition, the staggered exhaust path can prevent vent gas or foreign matter discharged outside the module from flowing into adjacent battery modules 10. Therefore, it is possible to delay as much as possible the occurrence of chain fires or thermal runaway in normal battery cells or battery modules 10 due to vent gas or flames.

[0067] Furthermore, a double fire-resistant layer is disposed on top of the module, minimizing heat transfer to surrounding modules and resulting thermal runaway. Furthermore, since there is no need to form a gap or space for opening a separate vent hole H1, a decrease in the energy density of the battery pack can be prevented. Conventional structures require a lid placed on top of the battery cells. When gas vents from a battery cell below the lid, the lid bursts upward to form a hole and release the gas. This requires an open space above the lid so that the burst lid can expand upward. Without sufficient open space, the lid does not burst sufficiently when gas is released, resulting in insufficient opening of the hole. In contrast, according to one aspect of the present invention, through-holes H2 and H3 are formed in a staggered pattern in the cover member 300, eliminating the need for a bursting mechanism and eliminating the need for open spaces in conventional lids. According to this aspect of the present invention, a gap can be secured between the pack case and the cover member 300, increasing design flexibility.

[0068] FIG. 5 is a cross-sectional view of a structure of a battery pack including a battery module according to one embodiment of the present invention, FIG. 6 is an enlarged view of a portion of FIG. 5, and FIGS. 7 and 8 are schematic views illustrating the movement and flow of vent gas on the upper surface of the battery module, respectively.

[0069] 5, a battery module 10 is housed inside a pack case (pack tray 410 and pack cover 420). A cover member 300 is disposed on the top surface of the battery module 10, and a first fire-resistant layer 301 and a second fire-resistant layer 304 cover the top of the battery module 10, so that the battery module 10 can withstand heat caused by vent gas, flames, sparks, etc. that occur during a thermal event, and can suppress thermal propagation (TP), such as propagation to adjacent modules.

[0070] 5 and 6, the first discharge hole H2 is disposed immediately above the vent hole H1, and the vent hole H1 is provided to communicate with the first discharge hole H2, and the second discharge hole H3 is disposed at a position offset from the first discharge hole H2 without overlapping with it, spaced apart by an amount corresponding to the distance between the first fire-resistant layer 301 and the second fire-resistant layer 304. This allows the vent hole H1 to be provided to communicate with the first discharge hole H2 and the second discharge hole H3 in order, but allows the discharge path to be formed in a staggered pattern.

[0071] If a specific battery cell ignites and generates a large amount of vent gas, the gas is discharged through the vent hole H1 formed at the top, then passes through the first exhaust hole H2, and hits the bottom wall of the second fire-resistant layer 304. As a result, the gas changes direction to the left and right, a predetermined distance from the first exhaust hole H2, and is discharged to the second exhaust hole H3. As a result, the flow of the vent gas forms a staggered vent path, as shown in FIG. 6. Also, referring to FIG. 7, a plurality of guide members 340 disposed between the first exhaust hole H2 and the second exhaust hole H3 guide the vent gas in one direction, helping to facilitate its discharge. In this way, the vent gas discharged through the vent hole H1 can be easily discharged through the staggered vent path formed between the first fire-resistant layer 301 and the second fire-resistant layer 304, effectively preventing heat accumulation and thermal explosion of the battery module 10.

[0072] 5 may move to the right along the inside of the pack case. In this case, there is a risk that the vent gas may enter (penetrate) the inside of the battery module 10 on the right.

[0073] 8, the second exhaust hole H3 and the first exhaust hole H2 are arranged at offset positions without overlapping each other, thereby blocking the inflow of vent gas. That is, the second exhaust hole H3 of the second fire-resistant layer 304 and the first exhaust hole H2 of the first fire-resistant layer 301 are connected to each other but are spaced a predetermined distance apart, and the vent gas is blocked by the guide members 340 on the flow path, preventing it from flowing into the battery module 10 through the vent hole H1.

[0074] In this way, even if the space between the battery module 10 and the pack case is narrow when the battery module 10 is housed inside the pack case, the vent gas is discharged through the zigzag vent gas discharge path provided between the double fire-resistant layers, thereby effectively preventing heat accumulation and thermal explosion of the battery module 10.

[0075] In addition, the staggered exhaust path can prevent vent gas or foreign matter discharged outside the module from flowing into adjacent battery modules 10. In particular, the flow path can be blocked by the guide members 340 on the flow path, preventing the gas from flowing into the battery module 10 through the vent hole H1. This can minimize the risk of ignition or thermal runaway in normal battery cells or battery modules 10 due to vent gas or flames.

[0076] Next, another embodiment of the battery module 10 of the present invention will be briefly described with reference to FIGS.

[0077] FIG. 9 is a perspective view of a fire-resistant coating layer applied to a base layer and a plate surface in a battery module according to another embodiment of the present invention, and FIG. 10 is a diagram schematically showing a path through which vent gas is discharged through a cover member in a battery module according to another embodiment of the present invention.

[0078] 9 and 10, the same reference numerals as in the previous drawings indicate the same components, and redundant explanations of the same components will be omitted, with the explanation focusing on differences from the above-described embodiment.

[0079] Referring mainly to FIG. 10 , in addition to the first fire-resistant layer 301 and the second fire-resistant layer 304, the cover member further includes a base layer 310 that is bonded to face the upper surface of the module case 200, and a fire-resistant coating layer 320 that is coated with a fire-resistant coating material 321 that is desorbed by the pressure of vent gas when vent gas is generated inside the module case 200.

[0080] Here, the base layer 310 may be disposed between the upper surface of the module case 200 and the first fire-resistant layer 301. The base layer 310 may be coupled to face the upper surface of the module case 200 and may be provided to have substantially the same size as the upper surface of the module case 200.

[0081] The base layer 310 may be at least one mesh plate having a plurality of mesh lines 312 and voids 313. The base layer 310 may be a component for blocking high-temperature flames and sparks that may travel with the vent gas. The base layer 310 is disposed to completely cover the vent hole H1 and can block the entry and exit of flames and sparks generated from the vent hole H1. This sufficiently filters and blocks flames and sparks that accompany the vent gas when the vent gas is discharged, preventing them from being discharged outside the battery pack and minimizing the risk of fire occurring to structures around the battery pack or other battery packs.

[0082] 9, the base layer 310 may include a support frame 314 disposed around the periphery of the mesh plate to support the mesh plate. The support frame 314 can firmly hold the mesh plate even when exposed to high temperatures, preventing twisting, distortion, and breakage of the plate surface.

[0083] A fire-resistant coating layer 320 is provided on the base layer 310, and the fire-resistant coating layer 320 may be configured to have a fire-resistant coating material 321 applied thereto that is desorbed by the pressure of vent gas when vent gas is generated inside the module case 200.

[0084] The fire-resistant coating layer 320 may be provided over the entire surface of the base layer 310 .

[0085] 10 , the fire-resistant coating layer 320 may be formed such that the fire-resistant coating material 321 is bonded to the mesh wire 312 to seal the voids 313. Here, the fire-resistant coating layer 320 may include one or more inorganic materials selected from ceramic, silicon, silica aerogel, and silica-based inorganic fibers. The particle size of the inorganic material may be formed to be relatively smaller than the voids 313.

[0086] The fire-resistant coating layer 320 may further include a binder that binds the fire-resistant coating material 321 to the mesh wire 312 and various additives. The binder may be a metal-affinity resin, such as polyvinyl acetal resin, acrylic resin, polyvinyl chloride resin, polyolefin resin, or epoxy resin. The binder includes the fire-resistant coating material 321 and facilitates adhesion to the mesh wire 312. The additives may include an adhesion promoter, a dispersant, a release agent, a heat stabilizer, an antioxidant, etc.

[0087] The fire-resistant coating layer 320 may be provided over the entire thickness of the base layer 310, or the fire-resistant coating layer 320 may be bonded to only a portion of the thickness of the base layer 310.

[0088] There are various methods for applying the fire-resistant coating layer 320 to the base layer 310. For example, a coating liquid may be prepared by dissolving the fire-resistant coating material 321 in an adhesive solvent, and then spraying the coating liquid using a spray method. The number of sprays may vary depending on the viscosity of the coating liquid, and the time and temperature of subsequent processes such as drying may also be adjusted. Alternatively, the base layer 310 may be immersed in a bath of the coating liquid before the application process.

[0089] According to this embodiment, the cover member may further include a fire-resistant coating layer that closes (covers) the vent hole H1 in addition to the components of the first fire-resistant layer 301 and the second fire-resistant layer 304 having the staggered exhaust path. The fire-resistant coating layer 320 may be detached due to gas pressure, opening the vent hole H1 as needed, thereby ensuring a sufficient exhaust path for the vent gas. Because the vent hole H1 is opened and closed by detaching the fire-resistant coating layer 320 from the base layer 310, a sufficient exhaust path for the vent gas may be ensured even if the space between the battery module 10 and the pack cover 420 (the space between the pack cover and the upper end of the module) is narrow. Therefore, the vent gas can be quickly exhausted to the outside, effectively preventing heat accumulation and thermal explosion of the battery module 10.

[0090] Furthermore, with this configuration, the vent holes H1 of adjacent modules can be more stably kept closed by the heat-resistant coating layer 320 compared to the first embodiment. This prevents external foreign objects, vent gas discharged to the outside of the battery module 10, or flames or sparks contained in such vent gas from flowing into other vent holes H1. This can minimize the risk of chain fires or thermal runaway in healthy battery cells 110 or battery modules 10 caused by vent gas or flames.

[0091] A battery pack according to an embodiment of the present invention may include one or more battery modules according to an embodiment of the present invention. In particular, to increase capacity and / or output, a battery pack according to an embodiment of the present invention may include a plurality of battery modules according to an embodiment of the present invention. In this case, the various components described above may be applied to each battery module. For example, each battery module may include a cell assembly 100, a module case 200, and a cover member 300. The plurality of battery modules 10 may be housed inside a pack case. Furthermore, in the case of a battery module according to an embodiment of the present invention, even if other battery modules are located in front or behind the battery module, propagation of thermal runaway between the modules can be effectively prevented.

[0092] In addition to the battery module and pack case, a battery pack according to one aspect of the present invention may further include various components, such as a battery management system (BMS), bus bars, relays, current sensors, fuses, and other battery pack components that are publicly known at the time of filing of the present invention, in the internal space of the pack case.

[0093] The battery module according to an embodiment of the present invention or the battery pack according to an embodiment of the present invention can be applied to automobiles such as electric vehicles and hybrid vehicles. That is, the automobile according to an embodiment of the present invention may include the battery module according to an embodiment of the present invention or the battery pack according to an embodiment of the present invention. Furthermore, the automobile according to an embodiment of the present invention may further include, in addition to the battery module or battery pack, various other components included in the automobile. For example, the automobile according to an embodiment of the present invention may further include, in addition to the battery module according to an embodiment of the present invention, a vehicle body, a motor, a control device such as an electronic control unit (ECU), and the like.

[0094] Furthermore, the battery module according to an aspect of the present invention or the battery pack according to an aspect of the present invention can be applied to an energy storage system (ESS), i.e., the energy storage system according to an aspect of the present invention may include the battery module according to an aspect of the present invention or the battery pack according to an aspect of the present invention.

[0095] Although the present invention has been described above using limited embodiments and drawings, the technical concept of the present invention is not limited to these in any way, and it goes without saying that a person having ordinary knowledge in the technical field to which the present invention pertains can make various modifications and variations within the scope of the technical concept of the present invention and the equivalent scope of the appended claims.

[0096] Meanwhile, although directional terms such as up, down, left, right, front, and rear are used in this specification, it will be obvious to those skilled in the art of the present invention that these terms are used merely for ease of explanation and may differ depending on the position of the object in question, the position of the observer, etc. [Explanation of symbols]

[0097] 10 Battery Module 100 Cell Assembly 110 battery cells 112 Electrode Lead 200 Module Case 210 Case body H1 vent hole 220 End Plate 300 Cover member 301 1st fireproof layer H2 1st discharge hole 304 Second fireproof layer H3 2nd discharge hole 307 Gap member 310 Basal Layer 311 Mesh Plate 312 Mesh Netting Wire 313 void 314 Support Frame 320 fire-resistant coating layer 321 Fire-resistant coating materials 340 Guide member 420 Pack Cover

Claims

1. a cell assembly including a plurality of battery cells stacked on one another; a module case that houses the cell assembly in its internal space and has a vent hole; a cover member including a plurality of spaced-apart fire-resistant layers, each having a discharge hole formed therein, the cover member being coupled to an outer surface of the module case such that the vent holes and the discharge holes communicate with each other; Including, The battery module is configured such that the discharge hole of one of the fire-resistant layers and the discharge hole of the other fire-resistant layer facing it do not overlap each other.

2. The fire-resistant layer is two layers, The fire-resistant layer is a first fire-resistant layer having a first discharge hole formed therein; a second fire-resistant layer having a second discharge hole formed therein; The battery module of claim 1 , comprising:

3. 3. The battery module of claim 2, wherein the cover member further comprises a gap member provided between the first fire-resistant layer and the second fire-resistant layer, the gap member separating the first fire-resistant layer and the second fire-resistant layer by an amount corresponding to a predetermined gap.

4. the second fire-resistant layer is provided on the first fire-resistant layer, The battery module according to claim 3 , wherein the first discharge hole and the second discharge hole are in communication with each other.

5. 5. The battery module according to claim 2, wherein at least one of the first fire-resistant layer and the second fire-resistant layer is provided with a plurality of guide members arranged between the first exhaust hole and the second exhaust hole to guide the exhaust of vent gas generated in the module case.

6. The battery module according to claim 5 , wherein the guide member is provided in an inclined shape so as to expand in a direction in which the vent gas is discharged.

7. The cover member is The basal layer, a fire-resistant coating layer provided over the entire surface of the base layer, the fire-resistant coating layer being coated with a fire-resistant coating material that is desorbed by the pressure of vent gas when vent gas is generated inside the module case; The battery module according to claim 3 or 4, further comprising:

8. The battery module according to claim 7 , wherein the base layer is disposed between the upper surface of the module case and the first fire-resistant layer.

9. The basal layer is At least one mesh plate having a large number of mesh lines and voids; a support frame disposed on a periphery of the mesh plate to support the mesh plate; The battery module of claim 7 , comprising:

10. The battery module according to claim 9 , wherein the fire-resistant coating layer is formed such that the fire-resistant coating material is bonded to the mesh wire to shield the gap.

11. The battery module according to claim 9 , wherein the fire-resistant coating layer includes at least one inorganic material selected from the group consisting of ceramic, silicon, silica aerogel, and silica-based inorganic fiber.

12. The battery module according to claim 11 , wherein the particle size of the inorganic material is relatively smaller than that of the voids.

13. A battery pack comprising the battery module according to any one of claims 1 to 4.

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