Safety-enhanced battery modules and battery packs

Abstract

A battery module according to the present invention includes: a cell assembly including a plurality of stacked battery cells; a module case having a vent hole formed therein, the module case accommodating the cell assembly in an interior space of the module case; and a cover member having a plurality of fire-resistant layers each having an exhaust slit formed therein, the cover member being coupled to an outer surface of the module case such that the vent hole and the exhaust slits are in communication with each other. The exhaust slit of any one of the fire-resistant layers may be ruptured, and the exhaust slit of another adjacent fire-resistant layer may be opened by the rupture of the any one of the fire-resistant layers, and the exhaust slit may be selectively opened in only one direction from the inside to the outside of the module case.

Description

[Technical Field]

[0001] The present invention relates to a battery module and a battery pack, and more specifically to a battery module and a battery pack in which discharged matter generated inside the module is easily discharged through discharge slits of different patterns formed in two fire-resistant layers on the top of the module, while preventing re-flow into adjacent modules, thereby delaying thermal runaway.

[0002] This application claims priority based on Korean Patent Application No. 10-2023-0107851, filed on August 17, 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-ion 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-ion 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-ion 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-ion 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, 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 any one secondary battery experiences thermal runaway and becomes a trigger cell, the heat and flames can quickly spread to the surrounding secondary batteries, making it even more likely that a chain reaction fire will 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 narrow.

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

[0010] The present invention has been made in view of the above circumstances, and the problem to be solved by the present invention is to provide a battery module in which discharged materials such as high-temperature particles and vent gas generated in one battery module due to a thermal event are quickly discharged outside the battery module, while minimizing the flow of the discharged materials into other adjacent battery modules.

[0011] Another problem to be solved by the present invention is to provide a battery pack having enhanced safety by including such a battery module.

[0012] 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]

[0013] A battery module according to the present invention, which solves the above problems, includes a cell assembly having a plurality of stacked battery cells; a module case having a vent hole formed therein and accommodating the cell assembly in an interior space of the module case; and a cover member having a plurality of fire-resistant layers each having an exhaust slit formed therein, the cover member being coupled to an outer surface of the module case so that the vent hole and the plurality of exhaust slits are in communication with each other. The exhaust slit of any one of the fire-resistant layers can be ruptured, and the exhaust slit of another adjacent fire-resistant layer can be opened by the rupture of the any one of the fire-resistant layers, and the exhaust slit can be selectively opened in only one direction from the inside to the outside of the module case.

[0014] The plurality of fire-resistant layers may be two layers, and the fire-resistant layer may include a first fire-resistant layer portion having a first exhaust slit formed in the width direction of the module case or formed to correspond to the shape of the vent hole, and a second fire-resistant layer portion having a second exhaust slit formed in the longitudinal direction of the module case.

[0015] The second fire-resistant layer portion may be provided so as to overlap the first fire-resistant layer portion.

[0016] The first fire-resistant layer may be provided so as to cover the top surface of the module case, or may be provided so as to cover the top surface of the module case and both side surfaces in the longitudinal direction of the module case.

[0017] The second fire-resistant layer may be provided to cover an upper surface of the module case and both side surfaces in the longitudinal direction of the module case.

[0018] The first exhaust slit and the second exhaust slit are arranged so as to overlap each other in the vertical direction above the vent hole, and an imaginary boundary circle connecting the ends of the first exhaust slits formed in the width direction and an imaginary ellipse connecting the ends of the second exhaust slits can be arranged so as to overlap the shape of the opening of the vent hole.

[0019] The first exhaust slit has a partially cut rupture line formed therein, which ruptures and opens due to gas or solid discharge generated in any one of the module cases when a thermal event occurs, and the second exhaust slit has at least one continuously cut notch formed therein, which can open due to the rupture of the first exhaust slit.

[0020] The second exhaust slit of one of the module cases adjacent to one of the module cases in which a thermal event has occurred is configured to block re-inflow of the gaseous discharge or solid discharge, and the first exhaust slit adjacent to the second exhaust slit can support the second exhaust slit so as to limit deformation of the second exhaust slit in the thickness direction.

[0021] The rupture lines may extend in the width direction of the module case and may be spaced apart at predetermined intervals along the length of the module case.

[0022] The rupture line may be formed on the edge of the rupture membrane that corresponds to the shape of the opening of the vent hole, and bridge portions may be provided at regular intervals that connect the first fire-resistant layer portion and the rupture membrane.

[0023] The cut portion may be a cut line formed to be aligned with the longitudinal direction of the module case.

[0024] The cutouts may be multiple and may include a first cutout line formed in alignment with the longitudinal direction of the module case, and second cutout lines formed diagonally at both ends of the first cutout line.

[0025] The cut portion may include a first cut line formed in alignment with the longitudinal direction of the module case and second cut lines formed diagonally at both ends of the first cut line, and the orthogonal projection of the second cut line onto the vent hole may not overlap with the orthogonal projection of the bridge portion onto the vent hole.

[0026] The cover member may be made from an inorganic material, a mica material, a fire-resistant plastic, or a combination thereof.

[0027] The first fire-resistant layer portion may be made of an inorganic material or a mica material, and the second fire-resistant layer portion may be made of an inorganic material, a mica material, or a fire-resistant plastic.

[0028] Furthermore, according to the present invention, a battery pack including one or more of the above-described battery modules can be provided. [Effects of the Invention]

[0029] According to one aspect of the present invention, when a thermal event occurs, high-temperature particles, vent gas, and other discharged materials generated in any one battery module can be quickly discharged to the outside of the battery module through exhaust slits with different patterns formed in the dual fire-resistant layers at the top of the module, thereby significantly reducing the possibility of battery module deterioration or explosion.

[0030] According to one aspect of the present invention, the discharged matter discharged outside the battery module is blocked by the double fire-resistant layer of the adjacent battery module, minimizing re-entry of the discharged matter. As a result, it is possible to delay the heat propagation that would otherwise occur if a thermal runaway phenomenon occurred in one trigger cell were to spread to the surrounding secondary batteries one after another.

[0031] As described above, according to the present invention, in a trigger module including a trigger cell, high-temperature particles and vent gas are smoothly discharged to reduce heat accumulation within the battery module, and particles and flames discharged to the outside are prevented from flowing into adjacent battery modules, thereby delaying heat propagation between battery modules and enhancing the safety of the battery module.

[0032] Furthermore, the battery pack of the present invention has enhanced safety due to the inclusion of such a battery module.

[0033] 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]

[0034] [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 of a cover member in a battery module according to one embodiment of the present invention; FIG. [Figure 4] 4 shows a modified embodiment of the first fire-resistant layer in FIG. 3. FIG. [Figure 5] FIG. 2 is a perspective view of a second fire-resistant layer in a cover member of a battery module according to an embodiment of the present invention. [Figure 6] 3 is a top view of a battery module according to an embodiment of the present invention, showing a state in which a cover member is coupled to a module case; [Figure 7] FIG. 7 is a cross-sectional view taken along the line AA' in FIG. 6. [Figure 8] 1 is a schematic cross-sectional view of a structure of a battery pack including a battery module according to an embodiment of the present invention; [Figure 9] FIG. 10 is a top view of a first fire-resistant layer of a cover member of a battery module according to another embodiment of the present invention. [Figure 10] FIG. 10 is a top view of a second fire-resistant layer of a cover member of a battery module according to another embodiment of the present invention. [Figure 11] 10 is a top view of a battery module according to another embodiment of the present invention, in which a cover member is coupled to a module case. FIG. [Figure 12] 1 is a diagram illustrating a battery pack and a vehicle according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The cell assembly 100 may include one or more battery cells 110. Here, each battery cell 110 may refer to a secondary battery. The battery cell 110 refers to a secondary battery including an electrode assembly, an electrolyte, and a pouch case that houses the electrode assembly. In this embodiment, a pouch-type battery cell 110 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.

[0040] The pouch-type battery cell 110 includes an electrode assembly, a case that houses the electrode assembly, and a pair of electrode leads that are connected to the electrode assembly and extend outside the case to function as electrode terminals. The pair of electrode leads may extend forward and backward along the longitudinal direction of the battery cell 110 (±Y directions). Alternatively, if necessary, the electrode leads may be shaped to be located only at one end in the Y-axis direction, for example, the end in the −Y-axis direction. Although not shown, electrical components such as a bus bar, a bus bar frame, and a module connector may be mounted adjacent to the pair of electrode leads of the battery cell 110.

[0041] Such battery cells 110 may be stacked 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 X-axis direction) while standing upright in the vertical direction (the Z-axis direction).

[0042] 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 in the form of an assembly of a plurality of pouch-type battery cells 110 stacked in one direction (X-axis direction) with the wide surfaces of the battery cells 110 standing upright.

[0043] The module case 200 may have an internal space formed therein and may be configured to accommodate the battery cells 110 therein. The module case 200 is a component for protecting the cell assembly 100 from external impacts and may be preferably made of a material with excellent mechanical rigidity. The module case 200 in this embodiment may include a case body 210 and end plates 220 disposed on the front and rear sides of the case body 210.

[0044] The case body 210 may be formed in a rectangular tubular shape having an open end O at both ends in the longitudinal direction (Y-axis direction) and a hollow structure with an open interior. 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, with openings formed at the front and rear ends, respectively.

[0045] 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 the 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, and an upper cover that closes the upper open end of the lower case.

[0046] The case body 210 may be provided so that the cell assembly 100 can be inserted into the interior thereof along the longitudinal direction. That is, the case body 210 may be configured so that the battery cells 110 stacked in multiple layers can be inserted therein by a sliding or interference fit. For the interference fit connection, there may be little gaps between the upper and lower surfaces of the case body 210 and the upper and lower ends of the battery cells 110, and there may also be little gaps between both side surfaces of the case body 210 and both sides of the battery cells 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 cells 110.

[0047] The end plates 220 may be disposed at both longitudinal ends of the cell assembly 100, i.e., at the front and rear, where the electrode leads of the battery cells 110 are located, and may be configured to be coupled to the open end O of the case body 210. The end plates 220 are configured to cover connection portions between the bus bar frame and the electrode leads when the electrode leads of the battery cells 110 are connected to the bus bar frame so that they are not exposed to the outside. The end plates 220 may be configured, for example, to have an inner surface made of an insulating material and an outer surface made of a metal material and to be fixedly coupled to the case body 210 by welding. Meanwhile, although not shown for ease of illustration, the end plates 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.

[0048] The module case 200 configured as described above may have a vent hole H formed on at least one side thereof. The vent hole H may be configured to allow discharged materials, such as vent gas, generated and ejected from the cell assemblies 100 housed in the internal space of the module case 200 to be discharged to the outside from the internal space of the module case 200. For example, the module case 200 may be formed in a sealed shape except for the vent hole H. The vent hole H may be formed in a completely open shape so as to penetrate the module case 200 in an internal to external direction.

[0049] The vent hole H in this embodiment has a predetermined width in the width direction of the module case 200, and may be provided in the shape of a kind of elongated hole formed in a longitudinal direction of the module case 200. As indicated by H in Fig. 2, a plurality of the vent holes H may be formed on the upper side of the module case 200. Meanwhile, the number and shape of the vent holes H may be changed in various ways, and the arrangement positions of the vent holes H may also be changed as necessary.

[0050] The cover member 300 may be disposed on the outer surface of the module case 200. Referring mainly to FIG. 2, the cover member 300 may be provided on the upper side of the module case 200. This allows the cover member 300 to be configured to cover the vent hole H formed on the upper surface of the module case 200. In addition, one component of the cover member 300 may be provided to cover both sides in the width direction (X-axis direction) of the module case 200 (or both sides in the longitudinal direction (Y-axis direction)).

[0051] The cover member 300 may include a fire-resistant layer. The fire-resistant layer may be made of a material that is fire-resistant or heat-resistant. Preferably, the fire-resistant layer is VO-rated or higher according to the UL 94 test. The fire-resistant layer may be made of an inorganic material (e.g., a fire retardant barrier (FRB) material), mica, fire-resistant plastic, or a combination thereof. This ensures heat resistance against high-temperature ejections such as vent gases, flames, and sparks that occur during a thermal event, allowing the cover member 300 to withstand high-temperature heat without melting and suppressing heat transmission to adjacent modules. Meanwhile, the fire-resistant layer may be made of any material that is fire-resistant or heat-resistant, in addition to the materials mentioned above.

[0052] The cover member 300 in this embodiment may be composed of a plurality of fire-resistant layers. Specifically, the plurality of fire-resistant layers may be composed of two layers, and the fire-resistant layers may include a first fire-resistant layer portion 310 provided with a first discharge slit 313 and a second fire-resistant layer portion 320 provided with a second discharge slit 323, as will be described in detail later.

[0053] The first fire-resistant layer 310 and the second fire-resistant layer 320 may be provided with a first discharge slit 313 and a second discharge slit 323, respectively. The first discharge slit 313 and the second discharge slit 323 may be provided to be overlapped in the vertical direction above the vent hole H. The first discharge slit 313 and the second discharge slit 323 may be provided to communicate with the vent hole H. As a result, discharged matter generated in the module case 200 due to a thermal event can pass through the vent hole H, the first discharge slit 313 of the first fire-resistant layer 310, and the second discharge slit 323 of the second fire-resistant layer 320, and be discharged to the outside of the battery module 10.

[0054] The first discharge slit 313 and the second discharge slit 323 are processed to have different shapes.

[0055] The exhaust slit of any one of the fire-resistant layers (in this embodiment, the first exhaust slit 313 of the first fire-resistant layer portion 310) is configured to rupture, and the exhaust slit of another adjacent fire-resistant layer (in this embodiment, the second exhaust slit 323 of the second fire-resistant layer portion 320) is configured to open when any one of the fire-resistant layers (in this embodiment, the first fire-resistant layer portion 310) ruptures, and can be configured to selectively open only in one direction from the inside to the outside of the module case 200.

[0056] More specifically, discharged matter generated by a thermal event is formed at high temperature and pressure, and when the pressure exceeds a predetermined level, the first discharge slit 313 adjacent to the vent hole H may burst and open. The second discharge slit 323 may open due to the rupture of the first fire-resistant layer 310. Therefore, discharged matter inside the battery module 10 can be discharged in one direction, from the inside to the outside of the module case 200. This allows discharged matter, such as high-temperature particles and vent gas generated in any one battery module 10, to be quickly discharged outside the battery module 10. Therefore, high-temperature particles and vent gas from the trigger cell can be smoothly discharged, reducing heat accumulation within the battery module 10. This reduces the possibility of deterioration or explosion of the battery module 10.

[0057] In contrast, the discharged material is in a relatively low temperature or pressure state, and therefore, it is possible to prevent the discharged material from passing through the cover member 300 of the adjacent battery module 10 and flowing back into the module case 200. The second fire-resistant layer 320 is primarily blocking particles and flames outside the other battery module 10, and the first fire-resistant layer 310 is secondarily blocking them, thereby preventing particles and flames discharged to the outside from the trigger module including the trigger cell from flowing back into the adjacent battery module 10.

[0058] As a result, the cover member 300 in this embodiment can be selectively opened in only one direction, from the inside to the outside of the module case 200. This can delay the heat propagation that would otherwise occur if a thermal runaway phenomenon occurred in any one trigger cell or triggered battery module 10 were to propagate to the surrounding secondary batteries in a chain reaction, and the battery module 10 including such a cover member 300 is a battery module with enhanced safety.

[0059] In addition, in the case of a conventional single cover member, discharge holes are formed by slitting, but there is a problem in that uniformity of discharge cannot be ensured because the precision of the slitting process is poor due to variations in processing and materials, etc. In contrast, in the case of this embodiment, double fire-resistant layers 310, 320 and each fire-resistant layer 310, 320 has double discharge slits 313, 323, which has the advantage of reducing variations in processing and materials.

[0060] The battery modules 10 may be housed in a pack case to form a battery pack (reference numeral 1 in FIG. 12). In this case, the pack case may include a lower case having an open top surface on which the battery modules 10 are placed, and a pack cover (reference numeral 60 in FIG. 8) coupled to the open top surface of the lower case. The lower case includes a plurality of partition walls, and the battery modules 10 housed in the pack case can be separated from each other by the partition walls. Since such a battery pack includes battery modules 10 with enhanced safety, the safety of the battery pack can also be enhanced.

[0061] The cover member 300 will be described in detail below.

[0062] 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, FIG. 4 is a diagram showing a modified embodiment of the first fire-resistant layer of FIG. 3, FIG. 5 is a perspective view of a second fire-resistant layer in a cover member of a battery module according to one embodiment of the present invention, and FIG. 6 is a top view of a battery module according to one embodiment of the present invention in which the cover member is coupled to a module case.

[0063] 3 to 6 and 1 and 2, the cover member 300 includes two fire-resistant layers. The fire-resistant layers may include a first fire-resistant layer portion 310 having a first discharge slit 313 formed therein and a second fire-resistant layer portion 320 having a second discharge slit 323 formed therein.

[0064] 2, the first fire-resistant layer 310 may be disposed immediately above the module case 200. As shown in Fig. 3, the first fire-resistant layer 310 may be provided in a flat plate type and may be provided so as to cover the upper surface of the module case 200. The first fire-resistant layer 310 may be disposed so as to abut against the upper surface of the module case 200 and may cover the vent hole H.

[0065] 4, as a modified embodiment, the first fire-resistant layer 310 may be provided to cover the top surface of the module case 200 and both longitudinal side surfaces of the module case 200. The first fire-resistant layer 310 may include side plates 311. In this case, the side plates 311 cover both side surfaces of the module case 200 to prevent discharged materials from being discharged in the width direction of the module case 200, and to efficiently block deterioration and heat propagation from battery modules 10 arranged adjacently in the width direction.

[0066] In addition, if a battery module including such a first fire-resistant layer portion 310 is integrated into a pack case including multiple partition walls (not shown) to form a battery pack, the partition walls within the pack case can be used to minimize the escape of thermal energy, thereby improving the overall heat resistance and durability of the pack case.

[0067] The first fire-resistant layer 310 may be provided with a first exhaust slit 313 formed in the width direction of the module case 200. The first exhaust slits 313 may be formed in the width direction (X-axis direction) of the module case 200, and may be provided in plurality so as to be spaced apart at predetermined intervals along the longitudinal direction (Y-axis direction). The first exhaust slits 313 may be disposed within an orthogonal projection area of ​​the vent hole H in the vertical direction (Z-axis direction).

[0068] The first discharge slit 313 may be formed with a rupture line 314. The rupture line 314 refers to a type of cut line that is partially cut and may be cut at regular intervals. That is, the rupture line 314 can be torn and burst to open when a predetermined pressure or more is applied.

[0069] The first fire-resistant layer 310 may be made of a fire-resistant material, or may be made by bonding an inorganic material or a mica material to a silicone pad. Since the first fire-resistant layer 310 has a fire-resistant plate surface, it can protect the battery module 10 from heat such as vent gas or flames generated in an adjacent module without melting.

[0070] The second fire-resistant layer 320 may be provided on the first fire-resistant layer 310. The second fire-resistant layer 320 may be bonded to the upper surface of the first fire-resistant layer 310 so as to face the upper surface. Like the first fire-resistant layer 310, the second fire-resistant layer 320 may also be made of a fire-resistant material, preferably an inorganic material, a mica material, or a fire-resistant plastic. The second fire-resistant layer 320 may also be made by bonding an inorganic material or a mica material to a silicone pad. Here, the fire-resistant plastic may be a material made of a plastic material such as polystyrene or polyurethane containing a fire-resistance enhancer such as silicate, aluminum salt, or titanium salt.

[0071] 5, the second fire-resistant layer 320 may be provided to cover the top surface of the module case 200, and side plates 321 may be provided to cover both side surfaces in the longitudinal direction (Y-axis) of the module case 200. The second fire-resistant layer 320 may protect the top and side surfaces of the module case 200 from external heat. In particular, if a modified embodiment of the first fire-resistant layer 310 is applied, two side plates 311 and 321 of a double fire-resistant layer may be formed on both side surfaces in the longitudinal direction of the module case 200, thereby further improving heat resistance.

[0072] The second fire-resistant layer 320 may be provided with a second exhaust slit 323. The second exhaust slit 323 may be formed in the longitudinal direction of the module case 200 and may be arranged to perpendicularly intersect with the first exhaust slit 313 when viewed from above. The second exhaust slit 323 may have at least one continuous cut portion formed therein. The cut portion may be a cut line 324 formed to be aligned with the longitudinal direction of the module case 200. The cut line 324 may be a continuous cut line. The cut line 324 may be arranged within the orthogonal projection area of ​​the vent hole H in the vertical direction.

[0073] 6, the first exhaust slit 313 of the first fire-resistant layer 310 and the second exhaust slit 323 of the second fire-resistant layer 320 may be provided to overlap each other in the vertical direction above the vent hole H. Specifically, the rupture line 314 of the first exhaust slit 313 may be formed in the width direction of the battery module 10 and may be formed to correspond to the shape of the opening of the vent hole H. In addition, the cut line 324 of the second exhaust slit 323 may be formed in the length direction of the battery module 10 and may be formed to a point that coincides with the shape of the opening of the vent hole H in the length direction (Y-axis direction).

[0074] In other words, an imaginary boundary circle connecting the ends of the first discharge slits 313 formed in the width direction and an imaginary ellipse connecting the ends of the second discharge slits 323 can be provided so as to overlap the shape of the opening of the vent hole H. This allows the vent hole H, the first discharge slits 313, and the second discharge slits 323 to communicate in the vertical direction, which will be described later.

[0075] The operating mechanism of the cover member 300 will now be described.

[0076] FIG. 7 is a cross-sectional view taken along the line AA' in FIG. 6, and FIG. 8 is a diagram schematically illustrating a cross section of a structure of a battery pack including a battery module according to an embodiment of the present invention.

[0077] Referring to Figures 6 and 7, the discharged matter generated inside the module case 200 can be discharged to the outside (for example, to the inside of the pack outside the module) through the first discharge slit 313 and the second discharge slit 323, which are connected to the vent hole H in the vertical direction as necessary.

[0078] Specifically, when a thermal event occurs due to a fire in a trigger cell or the like, the discharged matter is discharged through the vent hole H of the battery module 10 that has become the trigger.

[0079] At this time, when a predetermined temperature and pressure are exerted due to the high temperature and pressure of the discharged material, the rupture line 314 of the first discharge slit 313 is partially or entirely ruptured and opens.

[0080] Next, the ruptured first fire-resistant layer 310 heads toward the outside of the module case 200, and the already cut second discharge slit 323 naturally opens. Here, since the second discharge slit 323 has the continuously cut cut line 324 formed therein, it can naturally open and does not provide resistance to the discharged material.

[0081] Additionally, when first discharge slit 313 and second discharge slit 323 are opened, they can be opened in substantially the same shape as the opening of vent hole H, minimizing resistance to discharge.

[0082] According to one aspect of the present invention, high-temperature particles and discharged materials such as vent gas generated in the trigger module can be quickly discharged to the outside of the battery module 10. This significantly reduces the possibility of deterioration or explosion of the battery module 10.

[0083] Referring to FIG. 8 , when an event occurs in one of the battery modules included in the battery pack, discharged material from the battery cell 110 is discharged through the vent hole H, opening the first discharge slit 313 (see the arrow pointing in the Z-axis direction on the left side of the figure), and then strikes the pack cover 60 and flows back. At this time, the discharged material may be configured to prevent re-inflow into the adjacent battery module 10 (see the arrow bouncing back from the second fire-resistant layer 320 on the right side of the figure). That is, the second discharge slit 323 of the other module case 200 adjacent to the one module case 200 in which the thermal event occurred may be configured to prevent re-inflow of the gaseous or solid discharged material. This is because the pressure of the discharged material, particularly the vent gas, that has already been discharged outside the battery module 10 is relatively low, and the high temperature of the flame or solid discharged material is also relatively low. Such discharged material is primarily blocked by the second fire-resistant layer 320. The second discharge slit 323 can block the discharged matter from re-flowing into the interior of the module.

[0084] In addition, the first fire-resistant layer 310 secondarily blocks the re-inflow of discharged material. That is, the first discharge slit 313, which is positioned facing the lower part of the second discharge slit 323, can support the second discharge slit 323. In particular, although the second discharge slit 323 may be deformed in the thickness direction due to the pressure of the discharged material, the first discharge slit 313 can firmly support it from below. This configuration can block the re-inflow of the gas discharged material or solid discharged material. In this case, the rupture line 314 of the first discharge slit 313 can be configured to withstand the pressure of the discharged material during the re-inflow process.

[0085] As described above, according to the present embodiment, the discharged matter discharged to the outside of the battery module 10 is blocked by the double fire-resistant layers 310, 320 of the adjacent battery modules 10, minimizing re-inflow. As a result, it is possible to delay the heat propagation that would otherwise occur if a thermal runaway phenomenon occurred in one trigger cell or one triggered battery module 10 were to spread to the surrounding secondary batteries in a chain reaction. Therefore, in a battery pack including such battery modules 10, it is possible to delay the heat propagation between the battery modules 10, thereby enhancing safety.

[0086] Next, other embodiments of the battery module 10 of the present invention will be briefly described with reference to FIGS.

[0087] 9 and 10 are top views of a first fire-resistant layer and a second fire-resistant layer in a cover member of a battery module according to another embodiment of the present invention, and FIG. 11 is a top view of a battery module according to another embodiment of the present invention in which the cover member is coupled to a module case.

[0088] The same component numbers as in the previous drawings indicate the same components, and redundant explanations of the same components will be omitted, with the focus being on the differences from the previously described embodiment.

[0089] 9 to 11, the cover member 300 may include a first fire-resistant layer portion 310a having a first exhaust slit 313a formed to correspond to the shape of the vent hole H, and a second fire-resistant layer portion 320a having a second exhaust slit 323a formed in the longitudinal direction of the module case 200.

[0090] 9, the first discharge slit 313a is formed with a partially cut rupture line 314a, and the rupture line 314a is formed on the edge of the rupture membrane 315 corresponding to the shape of the opening of the vent hole H. Bridge portions 316 may be provided at regular intervals to connect the first fire-resistant layer portion 310 and the rupture membrane 315. The bridge portions 316 support the rupture membrane 315.

[0091] 10, second discharge slit 323a may have a plurality of continuous cutouts formed therein, and may include first cutout line 324a formed in alignment with the longitudinal direction of module case 200, and second cutout lines 324b formed obliquely at both ends of first cutout line 324a. Second cutout line 324b may be formed at the upper and lower ends of first cutout line 324a in the Y-axis direction.

[0092] Referring primarily to FIG. 11, the orthogonal projection of the second cut line 324b onto the vent hole H may not overlap with the orthogonal projection of the bridge portion 316 onto the vent hole H.

[0093] The first discharge slit 3113a of the first fire-resistant layer 310a can discharge the discharged material more quickly. In particular, when the discharged material bursts the bridge portion 316, the burst membrane 315 having an area the same as the opening of the vent hole H opens, allowing the discharged material inside to be discharged more quickly.

[0094] In addition, the second cut line 324b is set to be larger than the opening of the vent hole H, so that the size of the opening of the second discharge slit 323a for releasing the rupturable membrane 315 to the outside is further increased, thereby improving discharge efficiency.

[0095] Furthermore, the bridge portion 316 can be positioned offset from the second incision line 324b by preventing the orthogonal projection of the second incision line 324b onto the vent hole H from overlapping with the orthogonal projection of the bridge portion 316 onto the vent hole H. This allows the bridge portion 316 to support the lower portion of the weak second incision line 324b, which may be cut open naturally, thereby ensuring the strength of the cover member 300 in that area and more reliably preventing the re-entry of discharged matter from the outside.

[0096] According to this embodiment, high-temperature particles, vent gas, and other discharged materials generated in any one battery module 10 due to a thermal event can be quickly discharged to the outside of the battery module 10 through exhaust slits with different patterns formed in the double fire-resistant layers at the top of the module, thereby significantly reducing the possibility of deterioration or explosion of the battery module 10.

[0097] In addition, the discharged matter discharged to the outside of the battery module 10 is blocked by the double fire-resistant layers 310a, 320a of the adjacent battery modules 10, minimizing re-inflow. As a result, it is possible to delay the propagation of heat from a thermal runaway phenomenon occurring in one trigger cell or one triggered battery module 10 to the surrounding secondary batteries in a chain reaction.

[0098] FIG. 12 is a diagram illustrating a battery pack according to an embodiment of the present invention and a vehicle including the battery pack.

[0099] A battery pack 1 according to the present invention may include one or more battery modules 10 according to the present invention. In particular, to increase capacity and / or output, a battery pack 1 according to the present invention may include a plurality of battery modules 10 according to the present invention. In this case, the various components described above may be applied to each battery module 10. For example, each battery module 10 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 the pack case as described above. Furthermore, in the case of a battery module 10 according to an embodiment of the present invention, even if other battery modules 10 are located in front or behind the battery module 10, propagation of thermal runaway between the modules can be effectively prevented.

[0100] In addition to the battery module 10 and pack case, the battery pack 1 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 publicly known at the time of filing of the present invention, in the internal space of the pack case.

[0101] The battery module 10 according to the present invention or the battery pack 1 according to the present invention is applicable to a vehicle V such as an electric vehicle or a hybrid vehicle. That is, the vehicle V according to the present invention may include the battery module 10 according to the present invention or the battery pack 1 according to the present invention. Furthermore, the vehicle V according to the present invention may further include, in addition to the battery module 10 or the battery pack 1, a wide variety of other components included in the vehicle V. For example, the vehicle V according to the present invention may further include, in addition to the battery module 10 according to the present invention, a vehicle body, a motor, a control device such as an electronic control unit (ECU), and the like.

[0102] Furthermore, the battery module 10 according to the present invention or the battery pack 1 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 10 according to the present invention or the battery pack 1 according to the present invention.

[0103] 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.

[0104] 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]

[0105] 1 battery pack V Automobile 10 Battery Module 100 Cell Assembly 110 battery cells 200 Module Case 210 Case body H vent hole 220 End Plate 300 Cover member 310, 310a First fire-resistant layer 313, 313a First discharge slit 314, 314a rupture line 315 Rupture membrane 316 Bridge section 320, 320a second fire-resistant layer 311, 321 Side plates 323, 323a Second discharge slit 324 Cutting Line 324a First cut line 324b Second cut line

Claims

1. a cell assembly including a plurality of battery cells stacked on one another; a module case having a vent hole formed therein, the module case accommodating the cell assembly in an internal space of the module case; a cover member that includes a plurality of fire-resistant layers, each having an exhaust slit formed therein, and that is coupled to an outer surface of the module case such that the vent hole communicates with the plurality of exhaust slits; Including, a battery module configured such that the exhaust slit of any one of the fire-resistant layers is ruptured, and the exhaust slit of another adjacent fire-resistant layer is opened by the rupture of the one of the fire-resistant layers, and the exhaust slit selectively opens only in one direction from the inside to the outside of the module case.

2. the plurality of fire-resistant layers is two layers; The fire-resistant layer is a first fire-resistant layer provided with a first exhaust slit formed in the width direction of the module case or formed to correspond to the shape of the vent hole; a second fire-resistant layer portion provided with a second discharge slit formed in the longitudinal direction of the module case; The battery module of claim 1 , comprising:

3. The battery module according to claim 2 , wherein the second fire-resistant layer portion is provided so as to overlap the first fire-resistant layer portion.

4. 4. The battery module according to claim 3, wherein the first fire-resistant layer is provided to cover an upper surface of the module case, or to cover the upper surface of the module case and both side surfaces in the longitudinal direction of the module case.

5. The battery module according to claim 3 , wherein the second fire-resistant layer is provided to cover an upper surface of the module case and both side surfaces in the longitudinal direction of the module case.

6. the first exhaust slit and the second exhaust slit are provided above the vent hole so as to overlap each other in the vertical direction, 4. The battery module according to claim 3, wherein an imaginary boundary circle connecting the ends of the first exhaust slits formed in the width direction and an imaginary ellipse connecting the ends of the second exhaust slits are arranged to overlap the shape of the opening of the vent hole.

7. the first exhaust slit is opened when a partially cut rupture line is formed in any one of the module cases where a thermal event occurs and the rupture line is ruptured by a gas discharge or a solid discharge generated in the module case; The battery module according to claim 3 , wherein the second discharge slit has at least one continuous cut portion formed therein, and the cut portion opens when the first discharge slit bursts.

8. the second exhaust slit of the module case adjacent to any one of the module cases in which a thermal event has occurred is configured to block re-inflow of the gaseous discharge or solid discharge; The battery module according to claim 7 , wherein the first discharge slit adjacent to the second discharge slit supports the second discharge slit so as to limit deformation of the second discharge slit in a thickness direction.

9. 8. The battery module according to claim 7, wherein the rupture lines extend in a width direction of the module case and are arranged at predetermined intervals along a longitudinal direction of the module case.

10. 8. The battery module according to claim 7, wherein the rupture line is formed on an edge portion of the rupture membrane corresponding to the shape of the opening of the vent hole, and bridge portions are provided at regular intervals to connect the first fire-resistant layer portion and the rupture membrane.

11. The battery module according to claim 7 , wherein the cutout is a cutout line formed to align with the longitudinal direction of the module case.

12. The cut portions are plural, The cut portion is a first cut line formed in alignment with the longitudinal direction of the module case; second incision lines formed obliquely at both ends of the first incision line; The battery module of claim 11 , comprising:

13. The cut portion is a first cut line formed in alignment with the longitudinal direction of the module case; second incision lines formed obliquely at both ends of the first incision line; Including, The battery module according to claim 10 , wherein an orthogonal projection of the second cut line onto the vent hole does not overlap with an orthogonal projection of the bridge portion onto the vent hole.

14. The battery module according to claim 1 , wherein the cover member is made of an inorganic material, a mica material, a fire-resistant plastic, or a combination thereof.

15. the first fire-resistant layer is made of an inorganic material or a mica material, The battery module according to claim 2 , wherein the second fire-resistant layer is made of an inorganic material, a mica material, or a fire-resistant plastic.

16. A battery pack comprising the battery module according to any one of claims 1 to 15.

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