Safety-enhanced battery module

Abstract

A battery module according to the present invention includes: a cell assembly including 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 includes a plurality of fire-resistant layers, each having a discharge slot formed therein, and is coupled to an outer peripheral surface of the module case such that the vent hole and the discharge slot communicate with each other; wherein the discharge slot of one of the fire-resistant layers and the discharge slot of the other opposite fire-resistant layer are formed to extend in directions that intersect with each other, and the vent hole may be provided so as not to overlap with the portion where the discharge slots intersect.

Description

[Technical Field]

[0001] The present invention relates to a battery module, and more particularly to a battery module in which gas generated inside the module can be easily discharged through lattice-shaped exhaust slots formed in a crossing direction in a double layer of fire-resistant material at the top of the module, while preventing re-entry into adjacent modules, thereby preventing chain fires and explosions.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0034206, filed on March 15, 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 constructed by connecting multiple lithium ion secondary battery cells in series and / or parallel, and a battery pack is constructed by connecting the battery modules in series and / or parallel.

[0007] On the other hand, secondary batteries undergo chemical reactions during charging and discharging, which can lead to performance degradation if 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 to house these secondary batteries in a concentrated manner inside a module housing, if thermal runaway occurs in any one secondary battery and it becomes a trigger cell, the heat and flames can quickly spread to the surrounding secondary batteries, making it even easier for a chain reaction to occur among the secondary batteries.

[0008] In particular, from the viewpoint of integration, the maximum number of battery modules must be accommodated within a limited space, and therefore, there is not enough free space within 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 the present invention includes: a cell assembly including 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 includes a plurality of fire-resistant layers, each having a discharge slot formed therein, and is coupled to an outer peripheral surface of the module case such that the vent hole and the discharge slot communicate with each other; wherein the discharge slot of one of the fire-resistant layers and the discharge slot of the other opposite fire-resistant layer are formed to extend in directions that intersect with each other, and the vent hole may be provided so as not to overlap with the portion where the discharge slots intersect.

[0013] The fire-resistant layer may be two layers, and may include a first fire-resistant layer having a first discharge slot formed in the longitudinal direction of the module case, and a second fire-resistant layer having a second discharge slot formed in the width direction of the module case and arranged to intersect with the first discharge slot.

[0014] The second fire-resistant layer may be disposed so as to overlap the first fire-resistant layer, and the vent hole and the second discharge slot may be disposed so as not to overlap each other.

[0015] The vent hole and the first discharge slot may be connected in the vertical direction in a first section in which the vent hole is located, and the first discharge slot and the second discharge slot may be connected in the vertical direction in a second section in which the second discharge slot is located.

[0016] A horizontal discharge channel formed by the first discharge slot may be formed in a third section provided between the first section and the second section.

[0017] 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.

[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 wires to block the gaps.

[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] 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]

[0024] 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, vent gas can be discharged through lattice-shaped discharge slots and discharge channels provided between the double fire-resistant layers, thereby effectively preventing heat accumulation and thermal explosion of the battery module.

[0025] In addition, according to one aspect of the present invention, it is possible to prevent vent gas or foreign matter discharged outside the module from flowing into adjacent battery modules through the lattice-shaped exhaust slots and exhaust channels, thereby minimizing the risk of chain fire or thermal runaway in healthy battery cells or battery modules due to vent gas or flames.

[0026] Additionally, a double fireproof layer is placed on top of the module to minimize heat transfer to surrounding modules and the resulting thermal runaway.

[0027] Furthermore, since there is no need to form a gap or space (an open space in an existing lid) for opening a separate vent hole, the thickness of the cover member can be minimized, preventing a decrease in the energy density of the battery pack.

[0028] Furthermore, since the first discharge slot is provided in the longitudinal direction of the module, there are fewer restrictions on the position and shape of the vent hole of the battery module, allowing for greater freedom in design.

[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] FIG. 2 is a top view of a battery module according to an embodiment of the present invention. [Figure 4] 10A and 10B are diagrams illustrating modified examples of vent holes in a battery module according to an embodiment of the present invention. [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] 10A and 10B are diagrams illustrating a state in which a gap member is added to a cover member in a battery module according to an embodiment of the present invention. [Figure 8] FIG. 6 is a partial top view of FIG. 5. [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 schematic cross-sectional view of a structure of a battery pack including a battery module according to another embodiment of the present invention. 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 in a schematic manner for ease of explanation and clarity. Therefore, the size of each component does not reflect the actual size as a whole. 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 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 an assembly of a plurality of pouch-shaped 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. 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 interior-exterior direction.

[0046] In this embodiment, the vent hole H1 is elongated in the width direction and is provided in a substantially rectangular shape, but the vent hole H1 may be provided so as not to overlap with the intersection of the discharge slots S1 and S2. Because the vent hole H1 is arranged so as not to overlap with the intersection of the discharge slots S1 and S2, the vent gas discharged from the vent hole H1 may be discharged via a staggered (zigzag) path rather than directly (upward) communicating.

[0047] The cover member 300 is disposed on the outer surface of the module case 200, and in this embodiment, the cover member 300 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 300 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 each having an exhaust slot S1, S2 formed therein. The fire-resistant layers 301, 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. For example, a mica material may be used. This allows the fire-resistant layers 301, 304 to withstand heat generated by vent gas, flames, sparks, etc. during a thermal event and suppress thermal propagation (TP), such as propagation to adjacent modules.

[0049] Discharge slots S1 and S2 may be formed in the fire-resistant layers 301 and 304. The discharge slots S1 and S2 may be provided to communicate with the vent hole H1. That is, the vent hole H1 of the module case 200 and the discharge slots S1 and S2 formed in the fire-resistant layers 301 and 304, respectively, may be connected to each other. In this manner, 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.

[0050] The discharge slot S1 of one of the fire-resistant layers 301 and the discharge slot S2 of the other fire-resistant layer 304 facing it are formed to extend in directions that intersect with each other, and the vent hole H1 can be arranged so as not to overlap the portion where the discharge slots S1 and S2 intersect.

[0051] This prevents vent gas and foreign matter discharged outside the module from flowing into adjacent battery modules 10. That is, the zigzag discharge paths formed in the multiple fire-resistant layers 301, 304 minimize the flow of vent gas into adjacent modules. This will be described in detail in the next section describing the cover member 300.

[0052] FIG. 3 is a top view of a battery module according to an embodiment of the present invention, and FIG. 4 is a diagram showing a modified example of a vent hole in a battery module according to an embodiment of the present invention.

[0053] 2, the cover member 300 includes two fire-resistant layers 301 and 304. The fire-resistant layers 301 and 304 may include a first fire-resistant layer 301 having a first discharge slot S1 formed therein and a second fire-resistant layer 304 having a second discharge slot S2 formed therein.

[0054] The first fire-resistant layer 301 may be disposed directly above the module case 200. The first fire-resistant layer 301 may have a first exhaust slot S1 formed in the longitudinal direction of the module case 200. The first exhaust slot S1 is formed in the longitudinal direction (X-axis direction) of the module case 200, and may be provided in plurality at regular intervals along the width direction. Referring mainly to FIG. 3, the vent hole H1 and the first exhaust slot S1 may be vertically connected in a first section L1 where the vent hole H1 is located. As a result, vent gas generated inside the module case 200 may be discharged through the vent hole H1 and the first exhaust slot S1 connected thereto.

[0055] The first fire-resistant layer 301 may be made of a fire-resistant material, for example, mica. Since the first fire-resistant layer 301 has a fire-resistant plate surface, it can protect the module from heat caused by vent gas, flames, etc. generated in the adjacent module.

[0056] 3, a horizontal discharge channel C formed by the first discharge slot S1 may be formed in the third section L3 (a section between the first section L1 where the vent hole H1 is located and the second section L2 where the second discharge slot S2 is located, which is a kind of buffer section), as will be described later. That is, a portion of the first discharge slot S1 may form the discharge channel C.

[0057] To explain the exhaust channel C in more detail, the first fire-resistant layer 301 and the second fire-resistant layer 304 are arranged so as to overlap without any gaps, thereby forming a roughly "U"-shaped pipe line consisting of the upper surface of the module case 200, the bottom wall of the second fire-resistant layer 304, and the first exhaust slot S1 as both side walls, and the vent gas exhausted through the first exhaust slot S1 can be discharged horizontally through the exhaust channel C.

[0058] 2 and 4, the second fire-resistant layer 304 may be provided so as to overlap the first fire-resistant layer 301. In other words, the second fire-resistant layer 304 may be bonded to the first fire-resistant layer 301 while facing it. 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.

[0059] A plurality of second discharge slots S2 may be formed on the plate surface of the second fire-resistant layer 304. The second discharge slots S2 may be formed in the width direction (Y-axis direction) of the module case 200 and may intersect with the first discharge slots S1. The intersections between the first discharge slots S1 and the second discharge slots S2, i.e., the second section L2 where the second discharge slots S2 are located, may be vertically connected. As a result, vent gas discharged through the discharge channel C may be discharged above the battery module 10 or into the battery pack case through the second discharge slots S2.

[0060] With this configuration, 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 lattice-shaped discharge slots S1, S2 and the discharge channel C provided between the double fire-resistant layers, thereby effectively preventing heat accumulation and thermal explosion of the battery module 10.

[0061] Furthermore, according to one aspect of the present invention, the lattice-shaped discharge slots S1, S2 and the discharge channel C can prevent vent gas or foreign matter discharged outside the module from flowing into adjacent battery modules 10. For example, the third section L3 (see FIG. 3) functions as a kind of buffer section, lowering the temperature of the vent gas and reducing the pressure relative to when the gas is ejected. This reduces the flow of vent gas or foreign matter into adjacent battery modules 10, and can minimize the delay of chain fires or thermal runaway in healthy battery cells or battery modules 10 due to vent gas or flames.

[0062] Additionally, a double fireproof layer can be placed on top of the module to minimize heat transfer to surrounding modules and the resulting thermal runaway.

[0063] Furthermore, since there is no need to form a gap or space for opening the vent hole H1, the thickness of the cover member 300 can be minimized, preventing a decrease in the energy density of the battery pack. Conventional structures require a lid placed on top of a battery cell. 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 properly when gas is released, resulting in insufficient opening of the hole. In contrast, the present invention forms through-holes S1 and S2 in a staggered pattern in the cover member 300, eliminating the need for a rupture method and eliminating the need for open spaces in the conventional lid. The present invention also increases design flexibility by providing a gap between the pack case and the cover member 300.

[0064] Meanwhile, the lattice-shaped exhaust slots S1 and S2 formed in the first fire-resistant layer 301 and the second fire-resistant layer 304 of the cover member 300 allow the vent hole H1 to be arranged in various shapes and positions. That is, as shown in FIG. 4 , the shapes of the vent holes H2 and H3 can be changed, or the positions of the vent holes H1, H2, and H3 can be varied. In short, because the first exhaust slot S1 is provided in the longitudinal direction of the module case 200, vent gas can be discharged at any position that communicates with the first exhaust slot S1. This relaxes restrictions on the position, size, and shape of the vent holes H1, H2, and H3 of the battery module 10, thereby improving design flexibility. The cover member 300 according to this embodiment can be universally applied to various customer battery module shapes, particularly various vent holes H1, H2, and H3. Furthermore, assembly defects due to manufacturing tolerances and the like can be minimized.

[0065] Meanwhile, the cover member 300 according to one embodiment of the present invention does not include the gap member 307, but may be provided between the first fire-resistant layer 301 and the second fire-resistant layer 304 as shown in Fig. 7. In this case, the gap member 307 is provided between the first fire-resistant layer 301 and the second fire-resistant layer 304, and can separate the first fire-resistant layer 301 and the second fire-resistant layer 304 by an amount corresponding to a predetermined gap R (thickness of the gap member 307).

[0066] By virtue of this gap member 307, a uniform gap R is ensured across the entire surface of the first refractory layer 301 and the second refractory layer 304, and the number of exhaust passages for vent gas, together with the exhaust channel C, can be increased in proportion to the expanded space of the gap R.

[0067] The cover member 300 configured in this manner can withstand heat from vent gas, flames, sparks, etc. that occurs during a thermal event, and can suppress thermal propagation (TP), such as propagation to adjacent modules.

[0068] FIG. 5 is a cross-sectional view of the structure of a battery pack including a battery module according to one embodiment of the present invention, FIG. 6 is a partially enlarged view of FIG. 5, FIG. 7 is a view showing a state in which a gap member is added to a cover member in a battery module according to one embodiment of the present invention, and FIG. 8 is a partial top view of FIG. 5.

[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] The vent hole H1 and the first exhaust slot S1 may be in vertical communication with each other in the first section L1 where the vent hole H1 is located, so that vent gas generated inside the module case 200 can be discharged through the vent hole H1 and the first exhaust slot S1 communicating therewith, as shown in FIGS.

[0071] An exhaust channel C may be formed in a portion of the first exhaust slot S1, i.e., a horizontal exhaust channel C formed by the first exhaust slot S1 may be formed in the third section L3 (a type of buffer section between the first section L1 where the vent hole H1 is located and the second section L2 where the second exhaust slot S2 is located). The vent gas may be discharged horizontally through the exhaust channel C, as shown in FIG. 6.

[0072] The first discharge slot S1 and the second discharge slot S2 may be vertically connected at an intersection of the first discharge slot S1 and the second discharge slot S2, i.e., at a second section L2 where the second discharge slot S2 is located. As a result, the vent gas discharged through the discharge channel C may be discharged above the battery module 10 or into the pack case through the second discharge slot S2.

[0073] In this way, the vent gas discharged through the vent hole H1 can be easily discharged through the lattice-shaped discharge slots S1, S2 and the discharge channel C provided between the first fire-resistant layer 301 and the second fire-resistant layer 304, thereby effectively preventing heat accumulation and thermal explosion of the battery module 10.

[0074] 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.

[0075] In this case, the vent hole H1 is positioned so as not to overlap the intersection of the exhaust slots S1 and S2, thereby blocking the inflow of vent gas. That is, although the second exhaust slot S2 of the second fire-resistant layer 304 and the first exhaust slot S1 of the first fire-resistant layer 301 are in communication with each other via the exhaust channel C, a buffer section is provided corresponding to the length of the exhaust channel C (third section L3), preventing the gas from inflowing into the battery module 10. Due to the relative temperature and pressure drops in the exhaust channel C, re-entry into adjacent modules may be minimized.

[0076] 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 can be easily discharged through the lattice-shaped discharge slots S1, S2 and the discharge channel C provided between the double fire-resistant layers, thereby effectively preventing heat accumulation and thermal explosion of the battery module 10.

[0077] In addition, the zigzag discharge path prevents vent gas or foreign matter discharged outside the module from flowing into adjacent battery modules 10. In particular, a buffer section is provided above the flow path, corresponding to the length of the discharge channel C (third section L3), preventing the gas from flowing into the battery module 10. This minimizes the risk of vent gas or flames igniting normal battery cells or battery modules 10 or causing thermal runaway.

[0078] Next, another embodiment of the battery module 10 of the present invention will be briefly described with reference to FIGS.

[0079] FIG. 9 is a perspective view of a base layer and a fire-resistant coating layer applied to a plate surface in a battery module according to another embodiment of the present invention, and FIG. 10 is a schematic cross-sectional view of the structure of a battery pack including a battery module according to another embodiment of the present invention.

[0080] 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.

[0081] Referring mainly to FIG. 10 , in addition to the first fire-resistant layer 301 and the second fire-resistant layer 304, the cover member 300 further includes a base layer 310 coupled to face the upper surface of the module case 200, and a fire-resistant coating layer 320 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] Referring to FIG. 8, the fire-resistant coating layer 320 may be provided over the entire surface of the base layer 310 .

[0087] 9, 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 relatively smaller than the voids 313.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] According to this embodiment, the cover member 300 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 lattice-shaped discharge slots S1, S2 and the discharge channel C. The fire-resistant coating layer 320 is detached due to gas pressure, opening the vent hole H1 as needed, thereby ensuring a sufficient discharge 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 discharge path for the vent gas can 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 discharged to the outside, effectively preventing heat accumulation and thermal explosion of the battery module 10.

[0092] 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 normal battery cells 110 or battery modules 10 caused by vent gas or flames.

[0093] A battery pack according to the present invention may include one or more battery modules according to the present invention. In particular, to increase capacity and / or output, a battery pack according to the present invention may include a plurality of battery modules according to 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.

[0094] In addition to the battery module and pack case, the battery pack according to 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 known at the time of filing of the present invention, in the internal space of the pack case.

[0095] The battery module or battery pack according to the present invention can be applied to automobiles such as electric vehicles and hybrid vehicles. That is, the automobile according to the present invention may include the battery module or battery pack according to the present invention. Furthermore, the automobile according to 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 the present invention may further include, in addition to the battery module according to the present invention, a vehicle body, a motor, a control device such as an electronic control unit (ECU), and the like.

[0096] Furthermore, the battery module according to the present invention or the battery pack according to the present invention can be applied to an energy storage system (ESS), that is, the energy storage system according to the present invention may include the battery module according to the present invention or the battery pack according to the present invention.

[0097] 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.

[0098] 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]

[0099] 10 Battery Module 100 Cell Assembly 110 battery cells 112 Electrode Lead 200 Module Case 210 Case body H1, H2, H3 vent holes 220 End Plate 300 Cover member 301 1st fireproof layer S1 First ejection slot 304 Second fireproof layer S2 Second ejection slot C. Extrusion channel L1 First Section L2 2nd Section L3 Third Section 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 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 that includes a plurality of fire-resistant layers, each having a discharge slot formed therein, and that is coupled to the outer peripheral surface of the module case such that the vent holes and the discharge slots communicate with each other; Including, a discharge slot of one of the fire-resistant layers and a discharge slot of the other of the fire-resistant layers facing the one of the fire-resistant layers are formed to extend in directions intersecting each other, and the vent hole is provided so as not to overlap with the portion where the discharge slots intersect.

2. The fire-resistant layer is two layers, The fire-resistant layer is a first fire-resistant layer having a first discharge slot formed in the longitudinal direction of the module case; a second fire-resistant layer, the second discharge slot being formed in the width direction of the module case and intersecting the first discharge slot; The battery module of claim 1 , comprising:

3. the second fire-resistant layer is provided so as to overlap the first fire-resistant layer, The battery module according to claim 2 , wherein the vent hole and the second discharge slot do not overlap each other.

4. the vent hole and the first discharge slot are in communication with each other in the vertical direction in a first section in which the vent hole is located, The battery module of claim 3 , wherein the first discharge slot and the second discharge slot are vertically connected to each other in a second section where the second discharge slot is located.

5. 5. The battery module of claim 4, wherein a horizontal discharge channel formed by the first discharge slot is formed in a third section provided between the first section and the second section.

6. 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 to separate the first fire-resistant layer and the second fire-resistant layer by an amount corresponding to a predetermined gap.

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 of claim 2 , 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 wires to block the gap.

11. The battery module according to claim 7 , 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. A battery pack comprising the battery module according to any one of claims 1 to 11.

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