Battery module

Abstract

A battery module according to an embodiment of the present invention may include a module frame; a plurality of pouch-type battery cells arranged side by side within the module frame; and a plurality of vent holes formed through one surface of the module frame. The pouch-type battery cells may include an electrode assembly including an electrode lead; a battery case including a receiving portion that receives the electrode assembly, a short-side sealing portion located on a portion of the periphery of the receiving portion and from which the electrode leads protrude, and a long-side sealing portion located on another portion of the periphery of the receiving portion and folded toward the receiving portion; and a plurality of fixing members attached to the battery case and arranged at intervals along the length of the long-side sealing portion to fix the long-side sealing portion in a folded state. Each of the vent holes may have an area that does not overlap with the fixing member that is larger than an area that overlaps with the fixing member.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0160853 filed November 25, 2022 and Korean Patent Application No. 10-2023-0165914 filed November 24, 2023, and all contents disclosed in the Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery module including pouch-type battery cells. [Background technology]

[0003] Unlike primary batteries, secondary batteries can be charged and discharged, and are applicable to a variety of fields such as digital cameras, mobile phones, laptops, hybrid vehicles, etc. Examples of secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-metal hydride batteries, and lithium secondary batteries.

[0004] Among these secondary batteries, much research is underway on lithium secondary batteries, which have high energy density and discharge voltage. Recently, lithium secondary batteries have been manufactured as flexible pouch-type battery cells, and a number of these cells are connected together to form modules.

[0005] A pouch-type battery cell uses a pouch as an exterior material to encase an electrode assembly. The electrode assembly has a stacked structure of positive and negative electrode plates, each containing an electrode active material, and a separator interposed between the positive and negative electrode plates. A positive electrode tab is formed on one side of the positive electrode plate, and a negative electrode tab is formed on one side of the negative electrode plate. The tabs are connected to electrode leads, respectively, for connection to an external circuit. The electrode assembly is then sealed in the pouch, which is the exterior material.

[0006] The pouch includes a receiving portion that receives the electrode assembly and a sealing portion that is positioned around the receiving portion and seals the electrode assembly. The electrode leads may protrude from a portion of the sealing portion, and another portion may be folded to form a wing-folded portion to increase energy density. For example, the wing-folded portion may be formed by double-side folding (DSF). The wing-folded portion may not maintain its folded state after a certain period of time and may partially expand and protrude outward. To prevent this, the wing-folded portion may be fixed using a fixing member such as tape.

[0007] However, when a pouch-type battery cell malfunctions and generates flames or gases, the fixing member prevents the flames or gases from being discharged through the wing folding portion, but instead discharges them through the electrode lead.

[0008] If a flame or gas generated in one pouch-type battery cell in a battery module or battery pack is discharged toward an electrode lead, the flame may rapidly spread to the surrounding area, causing successive thermal runaway in adjacent battery cells, and a solution to this problem is required. Summary of the Invention [Problem to be solved by the invention]

[0009] One problem to be solved by the present invention is to provide a battery module that delays the venting of flames and gases generated within a pouch-type battery cell toward an electrode lead, and smoothly vents flames and gases vented from a pouch-type battery cell to the outside. [Means for solving the problem]

[0010] A battery module according to an embodiment of the present invention may include a module frame; a plurality of pouch-type battery cells arranged side by side within the module frame; and a plurality of vent holes formed through one surface of the module frame. The pouch-type battery cells may include an electrode assembly including an electrode lead; a battery case including a receiving portion that receives the electrode assembly, a short-side sealing portion located on a portion of the periphery of the receiving portion and from which the electrode leads protrude, and a long-side sealing portion located on another portion of the periphery of the receiving portion and folded toward the receiving portion; and a plurality of fixing members attached to the battery case and spaced apart from each other along the length of the long-side sealing portion to fix the long-side sealing portion in a folded state. Each of the vent holes may have an area that does not overlap with the fixing member that is larger than an area that overlaps with the fixing member.

[0011] A value obtained by subtracting the total length of the plurality of fixing members from the length of the long side sealing portion may be equal to or greater than the entire length of the short side sealing portion.

[0012] The spacing between the plurality of fixing members may be greater than the length of the fixing members.

[0013] The intervals between the plurality of fixing members may be greater than the lengths of the short side sealing portions.

[0014] The outermost fixing member of the plurality of fixing members may be positioned to correspond to an end of the receiving portion.

[0015] The total length of the plurality of fixing members may be 20% or less of the length of the long side sealing portion.

[0016] The total length of the plurality of fixing members may be 17% or less of the length of the long side sealing portion.

[0017] The total length of the plurality of fixing members may be 10% or more of the length of the long side sealing portion.

[0018] The length of each of the fixing members may be 3% to 6% or less of the length of the long side sealing portion.

[0019] The vent hole may be elongated in a direction parallel to the pouch-type battery cell and may have a length longer than that of the fixing member.

[0020] The length of the vent hole may be three times or more the length of the fixing member.

[0021] The area where the fixing members overlap the vent holes may be 1 / 3 or less of the total area of ​​the vent holes.

[0022] The area of ​​each of the vent holes that overlaps with the fixing member may be 1 / 3 or less of the area that does not overlap with the fixing member.

[0023] The plurality of vent holes may include a first vent hole that does not overlap with the fixing member; and a second vent hole that partially overlaps with the fixing member.

[0024] The plurality of vent holes may be arranged in a plurality of rows parallel to a stacking direction of the plurality of pouch-type battery cells, and a distance between the plurality of vent holes in a length direction of the pouch-type battery cells may be equal to or greater than a length of the fixing member.

[0025] Both ends of the vent hole may be rounded to be convex outward. [Effects of the Invention]

[0026] According to a preferred embodiment of the present invention, if a fire breaks out inside a pouch-type battery cell, gas and flames can be vented preferentially from the long-side sealing portion rather than from the short-side sealing portion from which the electrode leads protrude. This can maximize the time it takes for gas and flames to vent to the short-side sealing portion and minimize the rapid spread of flames to the periphery, which can cause continuous thermal runaway in adjacent battery cells.

[0027] Furthermore, during normal operation of the pouch-type battery cell, the long-side sealing portion can be reliably maintained in a folded state by the fixing member.

[0028] In addition, gas and flames vented at the long side sealing portion of the pouch-type battery cell can be smoothly discharged to the vent hole of the module frame.

[0029] Other effects may be included that can be easily predicted by a person skilled in the art from the configuration according to the preferred embodiment of the present invention. [Brief explanation of the drawings]

[0030] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention to be given later, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited only to the matters shown in such drawings. [Figure 1] 1 is a perspective view of a pouch-type battery cell included in a battery module according to an embodiment of the present invention. [Figure 2] FIG. 2 is a partial cross-sectional view taken along line AA' in FIG. [Figure 3] FIG. 2 is a front view of the pouch-type battery cell shown in FIG. 1. [Figure 4] FIG. 2 is a front view illustrating a modified example of the pouch-type battery cell illustrated in FIG. 1. [Figure 5a] FIG. 10 is a front view of a pouch-type battery cell according to a comparative example. [Figure 5b] FIG. 10 is a front view of a pouch-type battery cell according to a comparative example. [Figure 5c] FIG. 10 is a front view of a pouch-type battery cell according to a comparative example. [Figure 5d] FIG. 10 is a front view of a pouch-type battery cell according to a comparative example. [Figure 6] 1 is a perspective view of a battery module according to an embodiment of the present invention; [Figure 7] FIG. 7 is an exploded perspective view of the battery module shown in FIG. 6. [Figure 8] FIG. 7 is a plan view of the battery module shown in FIG. 6. [Figure 9a] FIG. 10 is a diagram illustrating the inside of a battery module according to an experimental example. [Figure 9b] FIG. 10 is a diagram illustrating the inside of a battery module according to an experimental example. DETAILED DESCRIPTION OF THE INVENTION

[0031]

[0033] The present invention will now be described in detail with reference to the accompanying drawings, in order to enable those skilled in the art to easily carry out the present invention. However, the present invention may be embodied in various different forms, and is not limited to the following embodiments.

[0032] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may unnecessarily obscure the gist of the present invention are omitted, and when referring to components in each figure in this specification, the same or similar reference symbols are used throughout the specification to refer to the same or similar components.

[0033] Furthermore, the terms and words used in this specification and claims should not be interpreted in a way that is limited to their ordinary and dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that an inventor can appropriately define the concept of a term in order to best explain his or her invention.

[0034] FIG. 1 is a perspective view of a pouch-type battery cell included in a battery module according to one embodiment of the present invention, FIG. 2 is a partial cross-sectional view taken along line A-A' in FIG. 1, FIG. 3 is a front view of the pouch-type battery cell shown in FIG. 1, and FIG. 4 is a front view illustrating a modified example of the pouch-type battery cell shown in FIG. 1.

[0035] A pouch-type battery cell 100 (hereinafter referred to as "battery cell") described below may be included in a battery module according to an embodiment of the present invention. The battery cell 100 may include an electrode assembly 110, a battery case 120, and a fixing member 130.

[0036] The electrode assembly 110 may be formed by interposing a separator between alternatingly arranged positive and negative electrodes. That is, the electrode assembly 110 may include a plurality of electrodes and a separator interposed between the plurality of electrodes to insulate the plurality of electrodes from each other. The electrode assembly 110 may be housed together with an electrolyte in a battery case 120, which may be housed in a housing 121, which will be described in more detail below.

[0037] The electrode assembly 110 may be of a stack type, a jelly roll type, a stack and folding type, or the like, and the type of the electrode assembly 110 is not limited.

[0038] The electrode assembly 110 may include electrode tabs connected to the positive and negative electrodes, respectively, and the electrode tabs may act as paths through which electrons can move between the inside and outside of the electrode assembly 110. The electrode tabs may include a positive electrode tab connected to the positive electrode and a negative electrode tab connected to the negative electrode. The positive electrode tab and the negative electrode tab may protrude in different directions from the electrode assembly 110, but are not limited thereto, and may protrude in various directions, such as protruding side by side in the same direction from one side.

[0039] The electrode assembly 110 may be provided with an electrode lead 111. The electrode lead 111 may electrically connect the electrode assembly 110 to the outside.

[0040] More specifically, the electrode lead 111 may be connected to an electrode tab of the electrode assembly 110 by spot welding or the like. A portion of the electrode lead 111 may be surrounded by an insulating member. The insulating member may be positioned to correspond to a short-side sealing portion 122 (described later) of the battery case 120. Thus, the insulating member insulates the electrode lead 111 from the short-side sealing portion 122 and maintains the sealing of the short-side sealing portion 122. Typically, the insulating member is a relatively thin insulating tape that is easily attached to the electrode lead 111, but is not limited thereto.

[0041] One end of the electrode lead 111 may be connected to the electrode tab, and the other end may protrude outside the battery case 120. The electrode lead 111 may include a positive electrode lead connected to the positive electrode tab and a negative electrode lead connected to the negative electrode tab. Since the positive electrode tab and the negative electrode tab are formed to protrude in various directions, the positive electrode lead and the negative electrode lead may also extend in various directions.

[0042] The battery case 120 may be formed by molding a laminate sheet, and can accommodate the electrode assembly 110 therein.

[0043] The battery case 120 may include a pair of cases connected by a bridge before or after sealing is released, and at least one of the pair of cases may have a recessed receiving portion 121, and the peripheral area of ​​the receiving portion 121 may form a terrace. When the bridge is folded with the electrode assembly 110 housed in the receiving portion 121, the terraces of the pair of cases may come into contact with each other, and three sides may be sealed by thermal fusion. In this case, the bridge may form the folding portion 124, and the terraces may form the sealing portions 122 and 123.

[0044] However, the present invention is not limited thereto, and the pair of cases may be separate members. In this case, the terraces of the pair of cases may be in contact with each other, and the four sides may be sealed by heat sealing. Such a cell case configuration is well known and should be easily understood by those skilled in the art.

[0045] The battery case 120 may include a receiving portion 121 that receives the electrode assembly 110, a short side sealing portion 122 that is located at a portion of the periphery of the receiving portion 121 and from which the electrode lead 111 protrudes, and a long side sealing portion 123 that is located at another portion of the periphery of the receiving portion 121 and is folded toward the receiving portion 121.

[0046] The receiving portion 121 may have a pocket shape, and the electrode assembly 111 may be received therein.

[0047] The short side sealing portions 122 may be located at a portion of the periphery of the receiving portion 121. For example, the short side sealing portions 122 may be located on both sides of the receiving portion 121 in the overall length direction and may extend in the overall width direction. The electrode leads 111 may protrude to the outside of the battery case 120 through the short side sealing portions 122.

[0048] The long side sealing portion 123 may be located at another part of the periphery of the receiving portion 121. For example, the long side sealing portion 123 may be located on one side of the receiving portion 121 in the overall width direction and may extend in the overall length direction. The long side sealing portion 123 may connect both short side sealing portions 122. The long side sealing portion 123 may be located on the opposite side of the folding portion 124. The long side sealing portion 123 may be a portion from which the electrode lead 111 does not protrude.

[0049] In the manufacturing process of the battery case, the long side sealing portion 123 is sealed after the short side sealing portion 122, so the corners of the sealing portions 122, 123 may be included in the long side sealing portion 123.

[0050] The long side sealing portion 123 may be folded at least once toward the storage portion 121. Preferably, the long side sealing portion 123 may be double-side folded (DSF).

[0051] The fixing member 130 may be attached to the battery case 120 to fix the long side sealing portion 123 in a folded state. That is, the fixing member 130 may fix the long side sealing portion 123 in a folded state. For example, the fixing member 130 may be an adhesive tape.

[0052] A plurality of fixing members 130 may be provided, and the fixing members 130 may be arranged at predetermined intervals from each other in the length direction of the long side sealing portion 123.

[0053] More specifically, the plurality of fixing members 130 may include a pair of outermost fixing members and at least one intermediate fixing member positioned between the pair of outermost fixing members, but is not limited thereto, and as shown in FIG. 4, the plurality of fixing members 130 may include only a pair of outermost fixing members.

[0054] The length L of the plurality of fixing members 130 may be the same as one another, but is not limited to this.

[0055] Meanwhile, if a fire occurs in the battery cell 100, more specifically, the electrode assembly 110, the battery case 120 may be damaged and gas may be emitted along with sparks and particles. If the gas is emitted toward the electrode lead 111, heat and flames may spread quickly to other nearby battery cells 100, and therefore a configuration to minimize this risk is required.

[0056] The portion of the long side sealing part 123 to which the fixing member 130 is attached does not swell, making it difficult for gas to vent. On the other hand, the portion of the long side sealing part 123 to which the fixing member 130 is not attached gradually expands as the internal pressure of the battery case 120 increases, increasing the internal volume of the battery case 120. This can delay the time it takes for gas to vent, and gas can be vented relatively preferentially.

[0057] Furthermore, a weakly sealed portion or an unsealed portion that is preferentially broken may be provided in a portion of the long side sealing portion 123 where the fixing member 130 is not attached, but is not limited thereto.

[0058] The value obtained by subtracting the total length L of the multiple fixing members 130 from the length L2 of the long side sealing portion 123 may be equal to or greater than the overall length of the short side sealing portion 122. That is, the overall length of the portion of the long side sealing portion 123 to which the fixing members 130 are not attached may be equal to or greater than the overall length of the short side sealing portion 122. The overall length of the short side sealing portion 122 may be equal to the sum of the lengths L1 of the short side sealing portions 122.

[0059] For example, as shown in FIG. 3, when the short side sealing portions 122 are formed on both sides of the receiving portion 121 and three fixing members 130 are attached to the long side sealing portion 123, the condition L2-3L≧2L1 can be satisfied.

[0060] As a result, the portion of the long side sealing portion 123 to which the fixing member 130 is not attached expands as the internal pressure of the gas increases, delaying the venting of the gas. In addition, since the gas is more likely to be vented preferentially through this portion, the venting of the gas toward the short side sealing portion 122 can be sufficiently delayed.

[0061] The interval between the plurality of fixing members 130 may be greater than the length L of each fixing member 130. The interval between the plurality of fixing members 130 may be greater than the length L1 of each of the short side sealing portions 122. As a result, when the internal pressure of the battery case 120 increases, the portion of the long side sealing portion 123 located between the plurality of fixing members 130 easily swells, allowing gas to be vented preferentially rather than through the short side sealing portion 122.

[0062] The outermost fixing member 130 among the plurality of fixing members 130 may be positioned to correspond to an end of the receiving portion 121. The end of the receiving portion 121 may refer to the end in the overall length direction. More specifically, the outermost fixing member 130 may be attached to the end of the receiving portion 121 or attached adjacent to the end of the receiving portion 121. As a result, the portion of the second sealing portion 123 through which gas is vented can be formed to be spaced apart from the first sealing portion 122, thereby more reliably delaying the spread of flame to the electrode lead 111.

[0063] The total length L of the plurality of fixing members 130 may be 20% or less, preferably 17% or less, of the length L2 of the long side sealing portion 123. If the total length L of the plurality of fixing members 130 is greater than 20% of the length L2 of the long side sealing portion 123, there may be a problem in that the time until the gas is vented by the short side sealing portion 122 may not be sufficiently delayed.

[0064] Furthermore, the total length L of the plurality of fixing members 130 may be 10% or more of the length L2 of the long side sealing portion 123. If the total length L of the plurality of fixing members 130 is less than 10% of the length L2 of the long side sealing portion 123, it may be difficult to sufficiently fix the long side sealing portion 123 in the folded state.

[0065] Furthermore, the length L of each fixing member 130 may be 6% or less of the length L2 of the long side sealing portion 123. This allows the portion of the long side sealing portion 123 to which the fixing member 130 is not attached to easily expand due to an increase in the internal pressure of the battery case 120, and an area through which gas can be vented can be evenly formed.

[0066] Furthermore, the length L of each fixing member 130 may be 3% or more of the length L2 of the long side sealing portion 123. As a result, the adhesive force of each fixing member 130 can prevent the fixing members 130 from being separated due to the restoring force of the folded long side sealing portion 123.

[0067] 5a to 5d are front views of a pouch-type battery cell according to a comparative example.

[0068] As shown in FIG. 5a, the fixing member 130a of the battery cell 100a according to the first comparative example is attached to the entire long side sealing portion 123, so that when a fire occurs within the battery cell 100a, gas can be vented almost immediately at the short side sealing portion 122, minimizing the effect of venting delay.

[0069] 5b, the fixing members 130b of the battery cell 100b according to the second comparative example are formed to be relatively long, and therefore the length of the portion of the long-side sealing portion 123 to which the fixing members 130b are not attached may not be sufficient. In this case, it may be difficult to sufficiently delay the venting of gas at the short-side sealing portion 122.

[0070] 5c, the fixing members 130c of the battery cell 100c according to the third comparative example are relatively short in length, but the number of fixing members 130c is relatively large, which may result in an insufficient length of the portion of the long side sealing portion 123 where the fixing members 130c are not attached. Also, because the spacing between the fixing members 130c is short, the portions of the long side sealing portion 123 between the fixing members 130c are unlikely to bulge, making it difficult for gas to vent. In this case, it is even more difficult to sufficiently delay gas venting at the short side sealing portion 122.

[0071] 5d, the battery cell 100d according to the fourth comparative example may not be provided with a fixing member at the long side sealing portion 123. In this case, it may be difficult to maintain the folded state of the long side sealing portion 123.

[0072] Hereinafter, experimental examples will be described with reference to FIGS. 3, 4, and 5a to 5d.

[0073] The inventor(s) attached a heating pad to the center of one side of the storage section 121 of the battery cell 100 and heated it, and measured the time (hereinafter referred to as "delay time") from the point at which gas venting occurred until the gas vented at the short side sealing section 122. The long side sealing section of the battery case used in each experiment was subjected to DSF (Double Side Folding) processing at 270 degrees, and the length of the long side sealing section was 548 mm. In addition, fixing tape was used as the fixing member.

[0074] In the case of the battery cell according to the first experimental example, the long side sealing portion was fixed entirely using a single fixing tape having a length of 548 mm (see FIG. 5a). As a result, gas was vented first at the short side sealing portion 122, and the delay time was measured as 0 seconds. In other words, it was confirmed that there was no flame retardant effect.

[0075] In the case of the battery cell according to the second experimental example, the long side sealing part was divided into three equal parts, and fixing tape with a length of 183 mm was attached to both ends (see Figure 5b). As a result, the delay time was measured to be 4 seconds, and it was confirmed that there was a flame delay effect on the battery cell unit. However, there is a problem in that it is difficult to guide the flame and gas to the vent holes formed on the top surface of the module frame, which will be described later.

[0076] In the case of the battery cell of the third experimental example, two 30mm long fixing tapes were attached at points 31.2mm away from both ends of the long side sealing part (see Figure 4). As a result, the delay time was measured to be 8 seconds, and it was confirmed that the battery cell had a flame retardant effect. However, because the center of the long side sealing part bulged out excessively, there was a risk of interference with the module frame (described later) and damaging the battery cell.

[0077] In the case of the battery cell of the fourth experimental example, two of the three 30mm long fixing tapes were attached 31.2mm away from both ends of the long side sealing part, and the remaining one was attached in the center of the long side sealing part (see Figure 3). As a result, the delay time was measured to be 4 seconds, and it was confirmed that the battery cell had a flame retardant effect.

[0078] In the case of the battery cell according to the fifth experimental example, two of the six 30 mm long fixing tapes were attached 31.2 mm from both ends of the long side sealing part, and the remaining four were attached at equal intervals (see Figure 5c). As a result, gas was vented first at the short side sealing part 122, and the delay time was measured as 0 seconds. This confirms that there is no flame retardant effect.

[0079] In the case of the battery cell of the sixth experimental example, no fixing tape was attached to the long side sealing part (see Figure 5d). As a result, the delay time was measured to be 10 seconds, and it was confirmed that the battery cell had a flame retardant effect. However, there was a problem in that the long side sealing part was not fixed.

[0080] These experimental examples confirmed that the battery cell 100 according to an embodiment of the present invention has a flame retardant effect while minimizing side effects (Experiment 4). In addition, it was confirmed that the battery cell 100 according to the modified example is also useful when compared with the battery cell 100 alone (Experiment 3).

[0081] FIG. 6 is a perspective view of a battery module according to one embodiment of the present invention, FIG. 7 is an exploded perspective view of the battery module shown in FIG. 6, and FIG. 8 is a plan view of the battery module shown in FIG.

[0082] A battery module 10 according to an embodiment of the present invention may include a plurality of battery cells 100 and a module frame 200 .

[0083] A plurality of battery cells 100 may be housed in a module frame 200. The plurality of battery cells 100 may be arranged side by side.

[0084] A plurality of battery cells 100 may be stacked on one another. The plurality of stacked battery cells 100 may form a battery cell stack 140. The battery cell stack 140 may also be provided with at least one heat dissipation pad 150. The heat dissipation pad 150 can dissipate heat from the battery cells 100. The heat dissipation pad 150 may be disposed between the plurality of battery cells 100 or may be disposed to cover the outermost battery cell 100.

[0085] The module frame 200 may form the exterior of the battery module 10. The module frame 200 may be made of a metal material having high strength.

[0086] The module frame 200 may have a variety of structures. As an example, the module frame 200 may be a mono-frame. The mono-frame may be a metal plate material with an upper surface, a lower surface, and both side surfaces integrated together. As another example, the module frame 200 may have a structure in which a U-shaped frame and an upper plate (upper surface) are combined together. The U-shaped frame may be a metal plate material with a lower plate (bottom surface) and side plates (both side surfaces) combined or integrated together. In addition, the module frame 200 may have a structure in which an L-shaped frame is combined together, or may have various structures not described in the above example.

[0087] The module frame 200 may have an internal space in which the battery cell stack 140 may be housed. More specifically, the module frame 200 may include a top surface, a bottom surface, and both side surfaces. Both ends of the module frame 200 in the length direction may be open and may be covered by end plates 400, which will be described later.

[0088] A plurality of vent holes 240 may be formed on one surface 210, preferably the top surface, of the module frame 200. If a fire occurs in a battery cell 100 inside the module frame 200, gas and flames can be quickly discharged through the vent holes 240.

[0089] Each vent hole 240 may be formed long in a direction parallel to the battery cell 100 .

[0090] Both ends of each vent hole 240 may be rounded outward, thereby reducing stress concentration near the corners of the vent hole 240 and increasing the open area of ​​the vent hole 240.

[0091] The vent holes 240 may be arranged in a number of rows parallel to the stacking direction of the pouch-type battery cells 100. For example, as shown in Fig. 8, the vent holes 240 may be arranged in five rows parallel to the stacking direction of the pouch-type battery cells 100. Therefore, a predetermined distance d may be formed in the longitudinal direction of the pouch-type battery cells 100 between the vent holes 240 in adjacent rows.

[0092] The battery module 10 may further include a bus bar frame 300 and an end plate 400 .

[0093] The bus bar frames 300 may be arranged on both sides of the battery cell stack 140 in the overall length direction. At least one bus bar 310 may be attached to the bus bar frame 300, and each bus bar 310 may be connected to an electrode lead 111 of a battery cell 100. The bus bar 310 may be configured to electrically connect a plurality of battery cells 100 to an external device.

[0094] The end plates 400 may be disposed on the outer sides of the bus bar frames 300. In other words, the bus bar frames 300 may be disposed between the battery cell stacks 120 and the end plates 400.

[0095] The end plates 400 may be coupled to the module frame 200. The end plates 400 may cover both open ends of the module frame 200. Openings 400H may be formed in the end plates 400, and the bus bars 310 may be electrically connected through the openings 400H. That is, the bus bars 310 of one battery module 10 may be electrically connected to another battery module 10 or a BDU (Battery Disconnect Unit) through the openings 400H.

[0096] Meanwhile, there is a risk that the fixing members 130 of the battery cell 100 may obstruct the discharge of gas through the vent holes 240. To address this concern, the area of ​​each vent hole 240 that does not overlap with the fixing members 130 may be larger than the area that overlaps with the fixing members 130. That is, each vent hole 240 may not overlap with the fixing members 130, or may overlap with the fixing members 130 by less than half of its area. This allows gas vented in the battery cell 100 to be smoothly vented through the vent holes 240.

[0097] More specifically, the area where the fixing members 130 overlap with the vent holes 240 may be 1 / 3 or less of the total area of ​​the vent holes 240. That is, the fixing members 130 may overlap only 1 / 3 or less of the total area of ​​the vent holes 240.

[0098] More specifically, the area of ​​each vent hole 240 that overlaps with the fixing member 130 may be 1 / 3 or less of the area that does not overlap with the fixing member 130. That is, only 1 / 3 or less of the area of ​​each vent hole 240 may overlap with the fixing member 130. This prevents some of the vent holes 240 from being clogged with the fixing member 130, and all of the vent holes 240 are evenly open, improving the reliability of gas venting.

[0099] The vent hole 240 may have a length longer than the fixing member 130. Preferably, the length of the vent hole 240 may be three times or more the length L of the fixing member 130. This increases the ease of designing and manufacturing the battery cell 100 because the position at which the fixing member 130 is attached to the battery case 120 is not restricted by the position of the vent hole 240.

[0100] The interval d between the plurality of vent holes 240 in the length direction of the battery cell 100 may be equal to or greater than the length L of the fixing member 30. This reduces the overlapping ratio of the fixing member 130 attached to any position of the battery case 120 with the vent holes 240, thereby maintaining high rigidity of the module frame 200.

[0101] The plurality of vent holes 240 may include first vent holes 241 that overlap with the fixing member 130 and second vent holes 242 that do not overlap with the fixing member 130. That is, some of the plurality of vent holes 240 may overlap with the fixing member 130, and other parts may not overlap with the fixing member 130. This allows for smooth gas venting through the plurality of vent holes 240 to some extent, while preventing the plurality of vent holes 240 from being formed too wide in the module frame 200, thereby preventing the rigidity of the module frame 200 from being excessively reduced.

[0102] However, this is not limited to this, and in other embodiments, it is possible that the plurality of vent holes 240 includes only the first vent hole 241 or only the second vent hole 242 through an appropriate arrangement of the plurality of vent holes 240.

[0103] 9a and 9b are diagrams illustrating the inside of a battery module according to an experimental example.

[0104] The conditions for the experimental example relating to the battery module described below are the same as those for the experimental example relating to the battery cell described above.

[0105] In the battery module of the first experimental example, two of the four 30mm-long fixing tapes were attached 31.2mm from both ends of the long-side sealing part, and the remaining two were attached at equal intervals. Also, a module frame with three vent holes was used, so that more than half of the outermost vent holes overlapped with the fixing tapes (see Figure 9a). As a result, the delay time was measured as 0 seconds the first time and 4.7 seconds the second time, confirming that the flame delay effect was random.

[0106] In the battery module of the second experimental example, two of the three 30mm-long fixing tapes were attached 31.2mm from both ends of the long-side sealing part, and the remaining tape was attached to the center of the long-side sealing part. In addition, a module frame with two vent holes was used, so that none of the vent holes overlapped with the fixing tapes (see Figure 9b). As a result, the delay time was measured as 5.2 seconds the first time and 10.4 seconds the second time, confirming the flame retardant effect.

[0107] Through these experimental examples, it was confirmed that the battery module 10 according to one embodiment of the present invention has a reliable flame retardant effect (Second Experimental Example).

[0108] The above description is merely an illustrative example of the technical concept of the present invention, and various modifications and variations may be made by a person having ordinary skill in the art to which the present invention pertains without departing from the essential characteristics of the present invention.

[0109] Therefore, the embodiments disclosed in the present invention are intended to explain rather than limit the technical idea of ​​the present invention, and the scope of the technical idea of ​​the present invention is not limited by such embodiments.

[0110] The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent range thereof should be interpreted as being included in the scope of the present invention. [Explanation of symbols]

[0111] 10 Battery Module 100 pouch-type battery cells 110 Electrode assembly 111 Electrode lead 120 Battery Case 121 Storage section 122 Short side sealing part 123 Long side sealing part 124 Folding section 130 Fixing member 200 Module Frame 210 (Module frame) one side 240 Vent Hole

Claims

1. Module frame; a plurality of pouch-shaped battery cells arranged side by side within the module frame; and a plurality of vent holes formed through one surface of the module frame; The pouch-type battery cell includes: an electrode assembly provided with an electrode lead; a battery case including: a receiving portion that receives the electrode assembly; a short-side sealing portion that is located in a portion of the periphery of the receiving portion and from which the electrode lead protrudes; and a long-side sealing portion that is located in another portion of the periphery of the receiving portion and is folded toward the receiving portion; and a plurality of fixing members attached to the battery case to fix the long side sealing portion in a folded state, the fixing members being spaced apart from one another in a length direction of the long side sealing portion; In the battery module, each of the vent holes has a larger area not overlapping with the fixing member than an area overlapping with the fixing member.

2. The battery module of claim 1 , wherein a value obtained by subtracting a total length of the fixing members from a length of the long-side sealing portion is equal to or greater than an entire length of the short-side sealing portion.

3. The battery module of claim 1 , wherein the intervals between the plurality of fixing members are greater than the lengths of the fixing members.

4. The battery module of claim 1 , wherein the intervals between the plurality of fixing members are greater than the lengths of the short-side sealing portions.

5. The battery module according to claim 1 , wherein an outermost fixing member among the plurality of fixing members is positioned to correspond to an end of the storage portion.

6. The battery module of claim 1 , wherein the total length of the plurality of fixing members is 20% or less of the length of the long-side sealing portion.

7. The battery module of claim 1 , wherein the total length of the plurality of fixing members is 17% or less of the length of the long-side sealing portion.

8. The battery module according to claim 6 or 7, wherein the total length of the plurality of fixing members is 10% or more of the length of the long-side sealing portion.

9. The battery module according to claim 1 , wherein the length of each of the fixing members is 3% to 6% of the length of the long-side sealing portion.

10. The battery module of claim 1 , wherein the vent holes are elongated in a direction parallel to the pouch-type battery cells and have a length longer than that of the fixing members.

11. The battery module according to claim 10 , wherein the length of the vent hole is at least three times the length of the fixing member.

12. The battery module of claim 1 , wherein an area where the fixing members overlap the vent holes is one-third or less of the total area of ​​the vent holes.

13. The battery module according to claim 1 , wherein an area of ​​each of the vent holes overlapping with the fixing member is equal to or less than one-third of an area not overlapping with the fixing member.

14. The plurality of vent holes are a first vent hole overlapping the fixing member; and The battery module according to claim 1 , further comprising a second vent hole that does not overlap with the fixing member.

15. the plurality of vent holes are arranged in a plurality of rows parallel to a stacking direction of the plurality of pouch-type battery cells; The battery module of claim 1 , wherein the intervals between the plurality of vent holes in the length direction of the pouch-type battery cell are equal to or greater than the length of the fixing member.

16. The battery module according to claim 1 , wherein both ends of the vent hole are rounded to be convex outward.

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