Battery module

Abstract

A battery module according to an embodiment of the present invention may comprise: a module frame; a plurality of pouch-type battery cells disposed parallel to each other 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 case including an electrode assembly having an electrode lead, a receiving portion receiving the electrode assembly, a short-side sealing portion located on a portion of an outer periphery of the receiving portion, from which the electrode lead protrudes, and a long-side sealing portion located on a portion of an outer periphery of the receiving portion, from which the electrode lead protrudes; the long side sealing part is positioned on the other part of the periphery of the receiving part and is folded towards the receiving part; and a plurality of fixing members attached to the battery case to fix the long-side sealing portion in the folded state, and arranged to be spaced apart from each other with respect to a longitudinal direction of the long-side sealing portion. An area where each vent hole does not overlap with the fixing member may be larger than an area where the vent hole overlaps with the fixing member.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2022-0160853, filed on November 25, 2022, and Korean Patent Application No. 10-2023-0165914, filed on November 24, 2023, the entire contents of which are incorporated herein by reference. Field of the Invention

[0004] The present invention relates to a battery module including a pouch-type battery cell. Background Art

[0005] Unlike primary batteries, secondary batteries can be rechargeable and dischargeable, and thus can be applied to various fields such as digital cameras, mobile phones, laptop computers, and hybrid vehicles. Secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-hydrogen batteries, and lithium secondary batteries.

[0006] Among these secondary batteries, the most research has been conducted on lithium secondary batteries with high energy density and discharge voltage. Recently, lithium secondary batteries have been manufactured as flexible pouch-type battery cells, and multiple lithium secondary batteries are connected to each other and used in a modular form.

[0007] In such a pouch-type battery cell in which a pouch is used as an exterior surrounding an electrode assembly, the electrode assembly has a structure in which a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate are stacked. A positive electrode tab is provided on one side of the positive electrode plate, and a negative electrode tab is provided on one side of the negative electrode plate. Each tab is connected to an external circuit by being connected to an electrode lead. The electrode assembly is sealed by a pouch as an exterior.

[0008] The pouch includes a receiving portion and a sealing portion. The receiving portion receives the electrode assembly, and the sealing portion is disposed around the receiving portion to seal the electrode assembly. In addition, the electrode lead may protrude from a part of the sealing portion, and a wing folding portion may be provided on another part of the sealing portion to increase the energy density. For example, the wing folding portion may be formed by double-sided folding (DSF). When a predetermined period of time elapses, the wing folding portion does not maintain its folded state, and a part of the wing folding portion unfolds to protrude to the outside. To prevent this phenomenon, a fixing member such as a tape may be used to fix the wing folding portion.

[0009] However, when a flame or gas is generated due to an abnormal operation of the pouch-type battery cell, there is a problem that the flame or gas may not be discharged toward the wing folding portion but toward the electrode lead.

[0010] In a battery module or a battery pack, when a flame or gas generated from a pouch-type battery cell is discharged toward an electrode lead, the flame can quickly spread to the surrounding environment and cause continuous thermal runaway of adjacent battery cells. Therefore, a solution to solve this problem is needed. Summary of the Invention

[0011] Technical Problem

[0012] An object of the present invention for solving the above problems is to provide a battery module that delays the discharge of a flame or gas generated in a pouch-type battery cell toward an electrode lead and smoothly discharges the flame or gas discharged from the pouch-type battery cell to the outside.

[0013] Technical Solution

[0014] A battery module according to an embodiment of the present invention may include: a module frame; a plurality of pouch-type battery cells disposed parallel to each other within the module frame; and a plurality of ventilation holes defined to penetrate one surface of the module frame, wherein each of the plurality of pouch-type battery cells includes: an electrode assembly provided with an electrode lead; a battery case including a receiving portion, a short-side sealing portion, and a long-side sealing portion, the receiving portion configured to receive the electrode assembly, the short-side sealing portion provided on a part of the outer periphery of the receiving portion and the electrode lead protruding from the short-side sealing portion, and the long-side sealing portion provided on another part of the outer periphery of the receiving portion and 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 and arranged at intervals from each other in a longitudinal direction of the long-side sealing portion. In each of the ventilation holes, an area not overlapping with the fixing members may be larger than an area overlapping with the fixing members.

[0015] A value obtained by subtracting a total length of the plurality of fixing members from a length of the long-side sealing portion may be equal to or greater than a total length of the short-side sealing portion.

[0016] A distance between the plurality of fixing members may be greater than a length of the fixing members.

[0017] A distance between the plurality of fixing members may be greater than a length of each of the short-side sealing portions.

[0018] An outermost fixing member among the plurality of fixing members may be provided to correspond to an end of the receiving portion.

[0019] A total length of the plurality of fixing members may be 20% or less of a length of the long-side sealing portion.

[0020] The total length of the plurality of fixing members may be 17% or less of the length of the long-side sealing portion.

[0021] The total length of the plurality of fixing members may be 10% or more of the length of the long-side sealing portion.

[0022] The length of each fixing member may be 3% to 6% or less of the length of the long-side sealing portion.

[0023] The vent hole may be arranged to be long in a direction parallel to the pouch-type battery cell and have a length longer than that of the fixing member.

[0024] The length of the vent hole may be at least three times the length of the fixing member.

[0025] With respect to the total area of the plurality of vent holes, the area where the plurality of fixing members overlap with the plurality of vent holes may be less than 1 / 3.

[0026] In each vent hole, the area overlapping with the fixing member may be less than 1 / 3 of the area not overlapping with the fixing member.

[0027] The plurality of vent holes may include: a first vent hole overlapping with the fixing member; and a second vent hole not overlapping with the fixing member.

[0028] The plurality of vent holes may be arranged to form a plurality of rows parallel to the stacking direction of the plurality of pouch-type battery cells, and the distance of the plurality of vent holes in the longitudinal direction of the pouch cell may be equal to or greater than the length of the fixing member.

[0029] Both ends of the vent hole may be rounded to protrude outward.

[0030] Advantageous Effects

[0031] According to a preferred embodiment of the present invention, when a fire occurs inside the pouch-type battery cell, gas and flame can be preferentially discharged from the long-side sealing portion rather than from the short-side sealing portion where the electrode leads protrude. Therefore, the time taken for the gas or flame to be discharged to the short-side sealing portion can be maximally delayed, and the phenomenon that the flame rapidly spreads to the surrounding environment and causes continuous thermal runaway of adjacent battery cells can be reduced.

[0032] In addition, when the pouch-type battery cell is operating normally, with the aid of the fixing member, the long-side sealing portion can be reliably maintained in a folded state.

[0033] In addition, the gas and flame discharged from the long-side sealing portion of the pouch-type battery cell can be smoothly discharged through the vent holes of the module frame.

[0034] In addition, effects that are obvious to those skilled in the art can be predicted based on the configurations of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following drawings attached to this specification show preferred embodiments of the present invention and are used to further understand the technical idea of the present invention and the detailed description of the present invention. Therefore, the present invention should not be construed as being limited to the drawings.

[0036] Figure 1 is a perspective view of a pouch-type battery cell provided in a battery module according to an embodiment of the present invention.

[0037] Figure 2 is along Figure 1 a cross-sectional view taken along line A-A' of

[0038] Figure 3 is Figure 1 a front view of the pouch-type battery cell shown in

[0039] Figure 4 is a front view showing Figure 1 a modified example of the pouch-type battery cell shown in

[0040] Figures 5a - 5d is a front view of a pouch-type battery cell according to a comparative example.

[0041] Figure 6 is a perspective view of a battery module according to an embodiment of the present invention.

[0042] Figure 7 is Figure 6 an exploded perspective view of the battery module shown in

[0043] Figure 8 is Figure 6 a plan view of the battery module shown in

[0044] Figure 9a and Figure 9b are views showing the inside of a battery module according to an experimental example. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings so that those of ordinary skill in the art can easily implement the present invention. However, the present invention can be implemented in several different forms and is not limited or restricted by the following embodiments.

[0046] To clearly explain the present invention, detailed descriptions of parts that are not related to this description or relevant known technologies and that may unnecessarily obscure the gist of the present invention are omitted. In this specification, reference numerals are added to the components in each figure. In this case, throughout the specification, the same or similar elements are given the same or similar reference numerals.

[0047] Furthermore, the terms or words used in this specification and the claims should not be construed restrictively in the ordinary meaning or based on the dictionary meaning, but should be construed as meanings and concepts that conform to the scope of the present invention based on the principle that the inventor can appropriately define the terms in order to describe and explain his invention in the best way.

[0048] Figure 1 is a perspective view of a pouch-type battery cell provided in a battery module according to an embodiment of the present invention, Figure 2 is along Figure 1 a cross-sectional view taken along line A-A' of Figure 3 is Figure 1 a front view of the pouch-type battery cell shown in Figure 4 and Figure 1 is a front view showing a modified example of the pouch-type battery cell shown in

[0049] A pouch-type battery cell 100 (hereinafter referred to as "battery cell") described below may be provided 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.

[0050] The electrode assembly 110 may be provided by interposing a separator between alternately arranged positive and negative electrodes. That is, the electrode assembly 110 may include a plurality of electrodes and a separator provided between the plurality of electrodes to insulate the plurality of electrodes from each other. The electrode assembly 110 may be accommodated in the battery case 120 together with an electrolyte, and more specifically, in an accommodation part 121 to be described later.

[0051] The electrode assembly 110 may be provided in a stacked type, a wound core type, a stacked and folded type, etc., and the type of the electrode assembly is not limited thereto.

[0052] The electrode assembly 110 may include electrode terminals connected to each of the positive and negative electrodes, and the electrode terminals may serve as a path for electrons to move between the inside and outside of the electrode assembly 110. The electrode terminals may include a positive electrode terminal connected to the positive electrode and a negative electrode terminal connected to the negative electrode. The positive electrode terminal and the negative electrode terminal may protrude from the electrode assembly 110 in different directions, but are not limited thereto. For example, the positive electrode terminal and the negative electrode terminal may protrude in various directions, for example, protruding parallel to each other from one side in the same direction.

[0053] The electrode assembly 110 may be provided with electrode leads 111. The electrode leads 111 may electrically connect the electrode assembly 110 to the outside.

[0054] More specifically, the electrode leads 111 may be connected to the electrode joints of the electrode assembly 110 by spot welding or the like. In addition, a part of the electrode leads 111 may be surrounded by an insulating member. The insulating member may be provided to correspond to the short-side sealing portion 122 of the battery case 120 (to be described later). Therefore, the insulating member may insulate the electrode leads 111 from the short-side sealing portion 122 and maintain the seal of the short-side sealing portion 122. Generally, an insulating tape that is easily attached to the electrode leads 111 and has a relatively thin thickness is used as the insulating member, but it is not limited thereto.

[0055] One end of the electrode leads 111 may be connected to the electrode joints, and the other end may protrude to the outside of the battery case 120. The electrode leads 111 may include a positive electrode lead connected to the positive electrode joint and a negative electrode lead connected to the negative electrode joint. Since the positive electrode joint and the negative electrode joint protrude in various directions, the positive electrode lead and the negative electrode lead may also extend in various directions.

[0056] The battery case 120 may be provided by molding a laminate sheet, and the electrode assembly 110 may be accommodated therein.

[0057] The battery case 120 may include a pair of cases and a receiving portion 121. The pair of cases are connected to each other by a bridging portion in a state before sealing or in a state where the seal is released, and the receiving portion 121 may be recessed and molded in at least one of the pair of cases. In addition, when the bridging portion is folded in a state where the electrode assembly 110 is accommodated in the receiving portion 121, the steps of the pair of cases may contact each other and be sealed on three sides by heat fusion. In this case, the bridging portion may provide a folding portion 124, and the steps may define the sealing portions 122 and 123.

[0058] However, it is not limited thereto, and the pair of cases may be separate members. In this case, the steps of the pair of cases may contact each other, and may be sealed on four sides by heat fusion. Such a configuration of the battery cell case is a well-known technique and will be easily understood by those skilled in the art.

[0059] The battery case 120 may include: a receiving portion 121 for receiving the electrode assembly 110; a short-side sealing portion 122 provided on a part of the outer periphery of the receiving portion 121 and from which the electrode leads 111 protrude; and a long-side sealing portion 123 provided on another part of the outer periphery of the receiving portion 121 and folded toward the receiving portion 121.

[0060] The receiving portion 121 may have a pocket shape and may accommodate the electrode assembly 111 therein.

[0061] The short-side sealing portion 122 may be provided on a part of the outer periphery of the accommodating portion 121. For example, the short-side sealing portion 122 may be provided on both sides in the longitudinal direction of the entire length of the accommodating portion 121 so as to extend in the full-width direction. The electrode lead 111 may protrude through the short-side sealing portion 122 out of the battery case 120.

[0062] The long-side sealing portion 123 may be provided on another part of the outer periphery of the accommodating portion 121. For example, the long-side sealing portion 123 may be provided on one side in the full-width direction of the accommodating portion 121 and may extend along the longitudinal direction. The long-side sealing portion 123 may connect the two short-side sealing portions 122 to each other. The long-side sealing portion 123 may be provided on the opposite side of the folding portion 124. The long-side sealing portion 123 may be a portion where no electrode lead 111 protrudes.

[0063] In the manufacturing process of the battery case, since the long-side sealing portion 123 is sealed later than the short-side sealing portion 122, the long-side sealing portion 123 may include the corners of the sealing portions 122 and 123.

[0064] The long-side sealing portion 123 may be folded toward the accommodating portion 121 at least once. Preferably, the long-side sealing portion 123 may be double-sided folded (DSF).

[0065] The fixing member 130 may be attached to the battery case 120 to fix the long-side sealing portion 123 in the folded state. That is, the fixing member 130 may fix the long-side sealing portion 123 in the folded state. For example, the fixing member 130 may be a tape.

[0066] The fixing member 130 may be provided in plurality. The plurality of fixing members 130 may be arranged at a predetermined interval in the longitudinal direction of the long-side sealing portion 123.

[0067] More specifically, the plurality of fixing members 130 may include a pair of outermost fixing members and at least one intermediate fixing member provided between the pair of outermost fixing members. However, it is not limited thereto, and as shown in Figure 4 , the plurality of fixing members 130 may include only a pair of outermost fixing members.

[0068] The lengths L of the plurality of fixing members 130 may be the same, but it is not limited thereto.

[0069] If a fire occurs in the battery cell 100 (more specifically, in the electrode assembly 110), the battery case 120 may be damaged, so that gas may be discharged together with sparks or particles. Here, when the gas is discharged toward the electrode lead 111, there is a risk that heat and flame may rapidly spread to other surrounding battery cells 100, so a configuration for minimizing this problem is required.

[0070] The portion of the long-side sealing portion 123 to which the fixing member 130 is attached may not expand and it may be difficult to discharge gas. On the other hand, as the internal pressure of the battery case 120 increases, the portion of the long-side sealing portion 123 to which the fixing member 130 is not attached can gradually expand, and the internal volume of the battery case 120 increases. Therefore, the time taken to discharge gas can be delayed, and gas can also be discharged relatively preferentially.

[0071] In addition, the portion of the long-side sealing portion 123 to which the fixing member 130 is not attached may be provided with a weak sealing portion or a non-sealing portion that preferentially ruptures. However, the present embodiment is not limited to this.

[0072] The value obtained by subtracting the sum of the lengths L of the plurality of fixing members 130 from the length L2 of the long-side sealing portion 123 may be equal to or greater than the total length of the short-side sealing portion 122. That is, the total length of the portion of the long-side sealing portion 123 to which the fixing member 130 is not attached may be greater than or equal to the total length of the short-side sealing portion 122. The total length of the short-side sealing portion 122 may be the sum of the lengths L1 of the respective short-side sealing portions 122.

[0073] For example, as Figure 3 shown, when the short-side sealing portions 122 are provided on each of the two sides of the accommodating portion 121, three fixing members 130 are attached to the long-side sealing portion 123, and for example, the conditional expression: L2 - 3L ≥ 2L1 can be satisfied.

[0074] As a result, the portion of the long-side sealing portion 123 to which the fixing member 130 is not attached can expand as the internal pressure of the gas increases, and the discharge of the gas can be delayed. In addition, the possibility that the gas is preferentially discharged through this portion can increase to sufficiently delay the discharge of the gas toward the short-side sealing portion 122.

[0075] The distance between the plurality of fixing members 130 may be greater than the length L of each fixing member 130. The distance between the plurality of fixing members 130 may be greater than each length L1 of the short-side sealing portion 122. Therefore, when the internal pressure of the battery case 120 increases, the portion of the long-side sealing portion 123 disposed between the plurality of fixing members 130 is likely to expand, and thus, gas can be preferentially discharged from here rather than from the short-side sealing portion 122.

[0076] Among the plurality of fixing members 130, the outermost fixing member 130 may be set to correspond to the end portion of the accommodating portion 121. The end portion of the accommodating portion 121 may refer to the end portion in the overall length direction. More specifically, the outermost fixing member 130 may be attached to the end portion of the accommodating portion 121, or may be attached near the end portion of the accommodating portion 121. Therefore, the portion for discharging gas in the second sealing portion 123 can be provided at a certain distance from the first sealing portion 122, and the diffusion of the flame to the electrode lead 111 can be more reliably delayed.

[0077] The total length L of the plurality of fixing members 130 may be 20% or less of the length L2 of the long-side sealing portion 123, preferably 17% or less. 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 is a problem that the time taken to sufficiently delay the discharge of gas to the short-side sealing portion 122 cannot be ensured.

[0078] In addition, 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 is difficult to sufficiently fix the long-side sealing portion 123 in the folded state.

[0079] In addition, the length L of each fixing member 130 may be 6% or less of the length L2 of the long-side sealing portion 123. Therefore, the portion of the long-side sealing portion 123 to which the fixing member 130 is not attached can be easily expanded by an increase in the internal pressure of the battery case 120, and a region for discharging gas can be provided uniformly.

[0080] In addition, the length L of each fixing member 130 may be 3% or more of the length L2 of the long-side sealing portion 123. Therefore, it is possible to prevent each fixing member 130 from coming off due to the restoring force of the folded long-side sealing portion 123.

[0081] Figures 5a - 5d is a front view of a pouch-type battery cell according to a comparative example.

[0082] Reference Figure 5a , since 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, if a fire occurs inside the battery cell 100a, gas can be discharged to the short-side sealing portion 122 almost immediately, and thus the discharge delay effect will be minimal.

[0083] Reference Figure 5b , the fixing members 130b of the battery cell 100b according to the second comparative example may be set to have relatively long respective lengths, and thus it may not be possible to sufficiently ensure the length of the portion of the long-side sealing portion 123 to which the fixing member 130b is not attached. In this case, it is difficult to sufficiently delay the discharge of gas to the short-side sealing portion 122.

[0084] Reference Figure 5c, each fixing member 130c of the battery cell 100c according to the third comparative example may have a relatively short length, but the number of the fixing members 130c may be relatively large. Therefore, it may not be possible to fully ensure the length of the portion of the long-side seal 123 where the fixing member 130c is not attached. In addition, since the distance between the fixing members 130c is short, it is difficult for the portion between the long-side seal 123 and the fixing member 130c to expand, and it is difficult for gas to be discharged. In this case, it is more difficult to sufficiently delay the discharge of gas to the short-side seal 122.

[0085] Reference Figure 5d , the battery cell 100d according to the fourth comparative example may not have a fixing member provided in the long-side seal 123. In this case, it is difficult to maintain the long-side seal 123 in a folded state.

[0086] Hereinafter, reference will be made to Figure 3 , Figure 4 and Figures 5a - 5d to describe the experimental examples.

[0087] When a heating pad is attached to and heated at the center of one surface of the accommodating portion 121 of the battery cell, the inventor measures the time taken for gas to be discharged from the time point when gas discharge occurs to the time point when gas is discharged into the short-side seal 122 (hereinafter referred to as "delay time"). The long-side seal of the battery case used in each experimental example is processed at 270 degrees of double-sided folding (DSF), and the length of the long-side seal is 548 mm. In addition, a fixing band is used as the fixing member.

[0088] In the case of the battery cell according to the first experimental example, a single fixing band with a length of 548 mm is used to completely fix the long-side seal (see Figure 5a ). As a result, gas is first discharged from the short-side seal 122, and the measured delay time is 0 seconds. In other words, it can be confirmed that there is no flame delay effect.

[0089] In the case of the battery cell according to the second experimental example, a fixing band with a length of 183 mm is attached to each of the two ends of the long-side seal divided into three parts (see Figure 5b ). As a result, the measured delay time is 4 seconds, so it is confirmed that the battery cell has a flame delay effect. However, there is a drawback in guiding the flame and gas to the vent hole defined in the top surface of the module frame to be described later.

[0090] In the case of the battery cell according to the third experimental example, two fixing bands (each having a length of 30 mm) are attached at points spaced 31.2 mm from each of the two ends of the long-side seal (see Figure 4) As a result, the measured delay time was 8 seconds, and thus, it was confirmed that the battery cell had a flame delay effect. However, since the central portion of the long-side sealing portion was excessively expanded, there was a risk of damaging the battery cell by interfering with the module frame, which will be described later.

[0091] In the case of the battery cell according to the fourth experimental example, two of the three fixing bands (each having a length of 30 mm) were attached at points spaced 31.2 mm from each of the two ends of the long-side sealing portion, and the remaining one fixing band was attached to the center of the long-side sealing portion (see Figure 3 ). As a result, the measured delay time was 4 seconds, and thus it was confirmed that the battery cell had a flame delay effect.

[0092] In the case of the battery cell according to the fifth experimental example, two of the six fixing bands (each having a length of 30 mm) were attached at points spaced 31.2 mm from each of the two ends of the long-side sealing portion, and the remaining four fixing bands were attached at equal intervals (see Figure 5c ). As a result, gas was first discharged from the short-side sealing portion 122, and the measured delay time was 0 seconds. In other words, it was confirmed that there was no flame delay effect.

[0093] In the case of the battery cell according to the sixth experimental example, no fixing band was attached to the long-side sealing portion (see Figure 5d ). As a result, the measured delay time was 10 seconds, and thus, it was confirmed that the battery cell had a flame delay effect. However, there was a problem that the long-side sealing portion was not fixed.

[0094] Based on these experimental examples, it was confirmed that the battery cell 100 according to the embodiment of the present invention minimized side effects while having a flame delay effect (fourth experimental example). In addition, it was confirmed that the battery cell 100 according to the modified example could also be used as a separate battery cell 100 (third experimental example).

[0095] Figure 6 is a perspective view of a battery module according to an embodiment of the present invention, Figure 7 is Figure 6 an exploded perspective view of the battery module shown in Figure 8 is Figure 6 a plan view of the battery module shown in

[0096] The battery module 10 according to an embodiment of the present invention may include a plurality of battery cells 100 and a module frame 200.

[0097] A plurality of battery cells 100 may be accommodated in the module frame 200. The plurality of battery cells 100 may be arranged side by side with each other.

[0098] A plurality of battery cells 100 can be stacked on top of each other. The plurality of battery cells 100 stacked on top of each other can form a battery cell stack 140. In addition, the battery cell stack 140 can 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 can be provided between the plurality of battery cells 100, or can be provided to cover the outermost battery cell 100.

[0099] The module frame 200 can define the appearance of the battery module 10. The module frame 200 can be made of a metal material with high strength.

[0100] The structure of the module frame 200 can be changed. As an example, the module frame 200 can be a single frame. The single frame can be a metal plate in which the top, bottom, and two surfaces are integrated with each other. As another example, the module frame 200 can have a structure in which a U-shaped frame and an upper plate (top surface) are connected to each other. The U-shaped frame can be a metal plate in which the lower plate (bottom surface) and the side plates (two side surfaces) are connected or integrated with each other. In addition, the structure of the module frame 200 can be set to a structure in which L-shaped frames are connected to each other, or can be set to various structures not described in the above examples.

[0101] The module frame 200 can have an internal space, and the battery cell stack 140 can be accommodated in the internal space. More specifically, the module frame 200 can include a top surface, a bottom surface, and two side surfaces. Both ends of the module frame 200 in the longitudinal direction can be open and can be covered by end plates 400 to be described later.

[0102] A plurality of ventilation holes 240 can be defined in one surface 210 of the module frame 200 (preferably on the top surface). If a fire breaks out in the battery cells 100 inside the module frame 200, the gas and flames can be quickly discharged through the ventilation holes 240.

[0103] Each ventilation hole 240 can be defined as being long in a direction parallel to the battery cells 100.

[0104] Both ends of each ventilation hole 240 can be rounded to bulge outwards. Therefore, the open area of the ventilation hole 240 can be increased while reducing the stress concentration near the corners of the ventilation hole 240.

[0105] A plurality of ventilation holes 240 can be arranged to form a plurality of rows parallel to the stacking direction of the plurality of pouch-type battery cells 100. For example, as Figure 8 shown, a plurality of ventilation holes 240 can be arranged in five rows parallel to the stacking direction of the pouch-type battery cells 100. Therefore, a predetermined distance d can be defined between two ventilation holes 240 in adjacent rows in the longitudinal direction of the pouch-type battery cells 100.

[0106] The battery module 10 may further include a bus bar frame 300 and end plates 400.

[0107] The bus bar frame 300 may be disposed at each of two sides of the battery cell stack 120 in the longitudinal direction. At least one bus bar 310 may be mounted on the bus bar frame 300, and each bus bar 310 may be connected to the electrode lead 111 of the battery cell 100. The bus bar 310 may be configured to electrically connect a plurality of battery cells 100 to an external device.

[0108] The end plates 400 may be disposed outside the bus bar frame 300. That is, the bus bar frame 300 may be disposed between the battery cell stack 120 and the end plates 400.

[0109] The end plates 400 may be coupled to the module frame 200. The end plates 400 may cover two open ends of the module frame 200. An opening 400H may be defined in the end plates 400, and the bus bar 310 may be electrically connected via the opening 400H. That is, the bus bar 310 of one battery module 10 may be electrically connected to another battery module 10 or a battery disconnect unit (BDU) via the opening 400H.

[0110] There is a risk that a plurality of fixing members 130 of the battery cells 100 interfere with the discharge of gas through the vent holes 240. To solve this problem, the area of each vent hole 240 that does not overlap with the fixing member 130 may be larger than the area that overlaps with the fixing member 130. That is, each vent hole 240 may not overlap with the fixing member 130, or the area where the vent hole 240 overlaps with the fixing member 130 is less than half of the area of the vent hole 240. Therefore, the gas discharged from the battery cell 100 can be smoothly discharged into the vent holes 240.

[0111] More specifically, relative to the total area of the plurality of vent holes 240, the area where the plurality of fixing members 130 overlap with the plurality of vent holes 240 may be less than 1 / 3. That is, the area where the plurality of vent holes 240 overlap with the fixing members 130 may be only 1 / 3 or less of the total area of the plurality of vent holes 240.

[0112] More specifically, the area where each vent hole 240 overlaps with the fixing member 130 may be less than 1 / 3 of the area that does not overlap with the fixing member 130. That is, the area where each vent hole 240 overlaps with the fixing member 130 is only 1 / 3 or less of the area of the vent hole 240. As a result, it is possible to prevent some of the vent holes 240 from being blocked by the fixing members 130, and all the vent holes 240 can be uniformly opened to improve the reliability of gas discharge.

[0113] The vent hole 240 may have a length longer than that of the fixing member 130. Preferably, the length of the vent hole 240 may be more than three times the length L of the fixing member 130. Accordingly, the position where the fixing member 130 is attached to the battery case 120 may not be limited to the position of the vent hole 240, thereby improving the ease of designing and manufacturing the battery cell 100.

[0114] The distance d in the longitudinal direction of the battery cell 100 between the plurality of vent holes 240 may be equal to or greater than the length L of the fixing member 130. Accordingly, the overlapping ratio of the fixing member 130 attached to any position of the battery case 120 with the vent hole 240 may be reduced, and the high rigidity of the module frame 200 may be maintained.

[0115] The plurality of vent holes 240 may include a first vent hole 241 overlapping with the fixing member 130 and a second vent hole 242 not overlapping with the fixing member 130. That is, some of the plurality of vent holes 240 may overlap with the fixing member 130, and the remaining vent holes may not overlap with the fixing member 130. Accordingly, while maintaining the smooth discharge of gas through the plurality of vent holes 240 to some extent, the plurality of vent holes 240 may be defined to prevent the module frame 200 from being too wide and having too low rigidity.

[0116] However, not limited thereto, in another embodiment, the plurality of vent holes 240 may be appropriately arranged such that the plurality of vent holes 240 include only the first vent hole 241 or only the second vent hole 242.

[0117] Figure 9a and Figure 9b is a view showing the inside of the battery module according to the experimental example.

[0118] The conditions of the experimental example related to the following battery module are the same as those of the experimental example related to the above battery cell.

[0119] In the case of the battery module according to the first experimental example, two of the four fixing bands (each having a length of 30 mm) are attached at points spaced 31.2 mm from each of the two ends of the long side sealing part, and the remaining two fixing bands are attached at equal intervals. In addition, a module frame having three vent holes is used, and thus more than half of the outermost vent holes overlap with the fixing bands (see Figure 9a ). As a result, in the first stage, the measured delay time was 0 seconds, and in the second stage, the measured delay time was 4.7 seconds, and thus it was confirmed that the flame delay effect occurred randomly.

[0120] In the case of the battery module according to the first experimental example, two of the three fixing straps (each having a length of 30 mm) are attached at points spaced 31.2 mm from each of the two ends of the long-side sealing portion, and the remaining one fixing strap is attached to the center of the long-side sealing portion. In addition, a module frame having two ventilation holes is used, so that all the ventilation holes do not overlap with the fixing straps (see Figure 9b ). As a result, in the first stage, the measured delay time was 5.2 seconds, and in the second stage, the measured delay time was 10.4 seconds, thus confirming the flame delay effect.

[0121] According to these experimental examples, it was confirmed that the battery module 10 according to the embodiment of the present invention has a reliable flame delay effect (second experimental example).

[0122] The subject matter disclosed above will be considered illustrative rather than restrictive, and the appended claims are intended to cover all such variations, enhancements, and other embodiments that fall within the true spirit and scope of the present invention.

[0123] Therefore, the embodiments of the present invention are considered illustrative rather than restrictive, and the technical idea of the present invention is not limited to the foregoing embodiments.

[0124] Therefore, the scope of the present invention is not defined by the detailed description of the present invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

[0125] [Description of Reference Numerals]

[0126] 10: Battery module 100: Pouch-type battery cell

[0127] 110: Electrode assembly 111: Electrode lead

[0128] 120: Battery housing 121: Accommodating portion

[0129] 122: Short-side sealing portion 123: Long-side sealing portion

[0130] 124: Folding portion 130: Fixing member

[0131] 200: Module frame 210: One surface (module frame)

[0132] 240: Ventilation hole

Claims

1. A battery module, the battery module comprising: A module frame; A plurality of pouch-type battery cells, the plurality of pouch-type battery cells being arranged parallel to each other within the module frame; And A plurality of ventilation holes, the plurality of ventilation holes being defined as penetrating through one surface of the module frame, Wherein each of the plurality of pouch-type battery cells comprises: An electrode assembly provided with electrode leads; A battery housing, the battery housing comprising a receiving portion, a short-side sealing portion, and a long-side sealing portion, the receiving portion being configured to receive the electrode assembly, the short-side sealing portion being provided on a part of the outer periphery of the receiving portion and the electrode leads protruding from the short-side sealing portion, and the long-side sealing portion being provided on another part of the outer periphery of the receiving portion and folded towards the receiving portion; and A plurality of fixing members, the plurality of fixing members being attached to the battery housing to fix the long-side sealing portion in a folded state and being arranged at intervals from each other in the longitudinal direction of the long-side sealing portion, Wherein, in each of the plurality of ventilation holes, the area that does not overlap with the fixing members is larger than the area that overlaps with the fixing members.

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

3. The battery module according to claim 1, wherein, The distance between the plurality of fixing members is greater than the length of the fixing members.

4. The battery module according to claim 1, wherein, The distance between the plurality of fixing members is greater than the length of each short-side sealing portion.

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

6. The battery module according to 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 according to 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 plurality of fixing members is 3% to 6% or less of the length of the long-side sealing portion.

10. The battery module according to claim 1, wherein, The ventilation holes are arranged to be long in a direction parallel to the pouch-type battery cells and have a length longer than the length of the fixing members.

11. The battery module according to claim 10, wherein, The length of the ventilation holes is at least 3 times the length of the fixing members.

12. The battery module according to claim 1, wherein, With respect to the total area of the plurality of ventilation holes, the area where the plurality of fixing members overlap with the plurality of ventilation holes is less than 1 / 3.

13. The battery module according to claim 1, wherein, In each of the plurality of ventilation holes, the area that overlaps with the fixing members is less than 1 / 3 of the area that does not overlap with the fixing members.

14. The battery module according to claim 1, wherein, The plurality of ventilation holes comprise: A first ventilation hole that overlaps with the fixing members; and A second ventilation hole that does not overlap with the fixing members.

15. The battery module according to claim 1, wherein, The plurality of ventilation holes are arranged to form a plurality of rows parallel to the stacking direction of the plurality of pouch-type battery cells, and The distance between the plurality of ventilation holes in the longitudinal direction of the pouch-type battery cells is equal to or greater than the length of the fixing members.

16. The battery module according to claim 1, wherein, Both ends of the ventilation holes are rounded and protrude outwards.

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