Secondary battery module

Abstract

The present invention relates to a secondary battery module, and more particularly, to a secondary battery module comprising a plurality of secondary batteries. The present invention provides a secondary battery module comprising: a plurality of secondary batteries in which an electrode assembly is accommodated in a battery case having a sealed edge; and an outer case in which an accommodation space for accommodating the plurality of secondary batteries is formed, in which the battery case includes: at least one folded portion folded at an edge such that an end portion thereof is wound inward; and at least one discharge portion through which gas inside the battery case is discharged as the seal is unsealed when the end portion at the edge is exposed to the outside and an internal pressure inside the battery case is higher than or equal to a predetermined pressure, the gas discharged from the discharge portion is discharged to the outside through the at least one exhaust portion.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Korean Patent Application No. 10-2022-0096405 filed on August 2, 2022 and Korean Patent Application No. 10-2023-0056993 filed on May 2, 2023, which are hereby incorporated by reference in their entirety.

[0004] The present invention relates to a secondary battery module, and more particularly, to a secondary battery module including a plurality of secondary batteries. Background Art

[0005] Recently, secondary batteries have attracted considerable attention as a power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), and the like developed to address restrictions such as air pollution caused by existing gasoline and diesel vehicles using fossil fuels.

[0006] Although one or two to three or four secondary batteries are used in small mobile devices, due to the demand for high power and large capacity in medium and large devices such as electric vehicles, a battery module in which multiple secondary batteries are electrically connected to each other, or a secondary battery pack in which multiple secondary battery modules are electrically connected to each other is used.

[0007] Among the secondary batteries currently on the market, one of the most popular secondary batteries may be a lithium secondary battery, which can be divided into a can type, a square type, and a pouch type according to the shape of its external material. Among them, the pouch type secondary battery is widely used in medium and large battery modules due to its high energy density and easy stacking.

[0008] With the recent increase in demand for secondary battery modules installed in vehicles, customers' demand for stability is also increasing. However, customers require an increase in the energy density of secondary batteries within the limited space of secondary battery modules. In this case, there is a limitation that the safety risks associated with fire and explosion of secondary batteries also increase together.

[0009] Specifically, a pouch-type secondary battery has a structure in which an electrode assembly is housed in a pouch-type battery case and the edges of the battery case are sealed. Here, when the secondary battery catches fire and the temperature of the secondary battery increases and the electrolyte evaporates inside the battery case to generate gas, the gas may tend to be ejected from a weakly sealed portion of the battery case without a specific path.

[0010] Here, when the gas is ejected to a position adjacent to an electrode lead or a bus bar, a fatal problem of rapid ignition of the secondary battery due to sparks may occur. In addition, when the gas ejected from the secondary battery is collected in the module housing, a problem of increased internal pressure of the module may also occur.

[0011] Therefore, it is necessary to develop a technology to solve the above problems. Summary of the invention

[0012] Technical issues

[0013] The present invention is invented to solve the above problems, and an object of the present invention is to provide a secondary battery module that can minimize the risk of fire by guiding gas ejected from a secondary battery to a designated location in the event of an emergency such as a secondary battery fire.

[0014] Technical Solution

[0015] A secondary battery module according to the present invention comprises: a plurality of secondary batteries in which electrode assemblies are accommodated in a battery case whose edges are sealed; and a housing having a housing space for accommodating the plurality of secondary batteries, wherein the battery case comprises: at least one folding portion on the edge, the folding portion being folded so that its ends are surrounded inwardly; and at least one discharge portion on the edge, when the ends are exposed to the outside and the internal pressure of the battery case is higher than a predetermined pressure, the seal is released in the at least one discharge portion to discharge the internal gas of the battery case, wherein at least one exhaust portion is provided in the housing, and the gas discharged from the exhaust portion is discharged to the outside through the at least one exhaust portion.

[0016] The exhaust portion may have a hole structure penetrating the inside and the outside of the housing.

[0017] The exhaust portion may be provided in a side portion of the housing.

[0018] The case may include: a support frame configured to support a stack of secondary batteries; and a pair of end plates coupled to the support frame and disposed on front and rear surfaces of the plurality of secondary batteries, wherein the vent may be disposed in the end plates.

[0019] Each of the secondary batteries may include an electrode lead protruding from a battery case, the end plate may be disposed to face the electrode lead, and the vent may be disposed at a position facing the battery case.

[0020] The exhaust portion may have a stepped hole structure inside the end plate.

[0021] The exhaust portion may gradually expand outward from the interior of the end plate.

[0022] The secondary battery module may also include a cover portion attached to the housing to correspond to the position of the vent portion, wherein the cover portion may be configured to seal the vent portion when the internal pressure of the accommodating space is less than a predetermined pressure, and when the internal pressure of the accommodating space is equal to or greater than the predetermined pressure, the cover portion may rupture to open the vent portion.

[0023] The cover may be made of a porous material.

[0024] The discharge portion may be folded at least once so that an end portion of the discharge portion is exposed to the outside.

[0025] The folded portion may be folded at least twice or more, and the discharge portion may be folded in an opposite direction to the folded portion.

[0026] The discharge portion may be folded less times than the folding portion.

[0027] A gap between inner surfaces disposed to face each other by being folded in the discharge portion may be larger than a gap between inner surfaces disposed to face each other by being folded in the folded portion.

[0028] The secondary battery module may further include an electrode lead protruding from at least one end portion of the battery case, wherein the discharge portion may be provided on the remaining end portions except for the end portion from which the electrode lead protrudes.

[0029] The folded portion may be provided on the remaining end portions except for the end portions from which the electrode lead protrudes.

[0030] The discharge portion may be provided as a plurality of discharge portions spaced apart from each other in a longitudinal direction of the battery case, and the discharge portion may be provided between the plurality of folded portions.

[0031] The secondary battery module may further include a film portion folded such that both ends thereof are connected to the discharge portion to surround an end of the discharge portion.

[0032] When the pressure inside the battery case is equal to or greater than a predetermined pressure, both end portions of the film portion may be expanded in a state of being connected to an outer surface of the discharge portion to release the sealing of the discharge portion.

[0033] The membrane portion may be made of a porous material.

[0034] The secondary battery may further include an adhesive member attached to an outer side of the folded portion so that the folded portion is maintained in the folded shape.

[0035] In the secondary battery, the sealing strength of the folded portion may be greater than the sealing strength of the discharge portion.

[0036] Technical Effects

[0037] The present invention can have the effect of preventing the internal pressure of the module from increasing by discharging the gas generated from the secondary battery to the outside of the housing by providing the vent portion in the housing.

[0038] Furthermore, the present invention can have the effect of minimizing the penetration of external foreign matter into the housing to easily ensure a gas exhaust passage by providing the exhaust portion in the side portion of the housing.

[0039] In addition, the present invention may further include a cover portion, which is arranged to correspond to the position of the exhaust portion so as to seal the exhaust portion when the internal pressure of the accommodating space is less than a predetermined pressure, thereby achieving the following effects: easily exhausting gas when the internal pressure of the module increases while minimizing the penetration of external foreign matter into the outer shell.

[0040] Furthermore, the present invention can have the effect of minimizing the risk of fire by guiding the gas generated inside the battery case to be discharged to a designated location by providing a discharge portion whose distal end is exposed to the outside at the edge of the battery case.

[0041] In addition, the present invention can have the effect of preventing external moisture and foreign matter from being introduced into the battery case while discharging gas within the battery case by further including a film portion connected to the discharge portion.

[0042] Therefore, the stability of the secondary battery module in the event of thermal runaway can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is an exploded perspective view illustrating the secondary battery module according to the first embodiment of the present invention.

[0044] Figure 2 is an example Figure 1 Detailed perspective view of the end plate.

[0045] Figure 3 is an example Figure 1 Side view of the end plate.

[0046] Figure 4 It is along Figure 3 A partial cross-sectional view taken along line AA in FIG.

[0047] Figure 5 is a partial cross-sectional view illustrating a portion of a secondary battery module according to Embodiment 2 of the present invention.

[0048] Figure 6 It is a front view illustrating a secondary battery applied to the present invention.

[0049] Figure 7 It is along Figure 6 A partial cross-sectional view taken along line BB in FIG.

[0050] Figure 8 It is along Figure 6 A partial cross-sectional view taken along line CC in FIG. 1 to illustrate a state before the gas is discharged through the discharge portion.

[0051] Fig. 9 is exemplified by Figure 8 A cross-sectional view showing the state of gas being discharged from the discharge portion.

[0052] Fig.10 is a cross-sectional view illustrating a state before gas is discharged through the discharge portion and the membrane portion in the secondary battery module according to Embodiment 3 of the present invention.

[0053] Fig.11 is exemplified by Fig.10 A cross-sectional view showing the state of gas discharge from the discharge portion and the membrane portion. DETAILED DESCRIPTION

[0054] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled 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 examples.

[0055] In order to clearly illustrate the present invention, the detailed description of the related known technology that is irrelevant to the description or may unnecessarily cover the gist of the present invention has been omitted, and in this specification, reference numerals are added to the components in each figure. In this case, the same or similar reference numerals are assigned to the same or similar elements throughout the specification.

[0056] Furthermore, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention, based on the principle that the inventor can appropriately define the concepts of the terms to best describe and explain his or her invention.

[0057] The present invention can provide a secondary battery module 100, which includes: a plurality of secondary batteries 110, wherein an electrode assembly 111 is accommodated in a battery shell 112 whose edges are sealed; and a shell 120, which has a plurality of secondary batteries 110 and an accommodating space therein, wherein the battery shell 112 may include: at least one folding portion 112a on the edge, which is folded so that its ends are surrounded inwardly; and at least one discharge portion 112b on the edge, which releases the seal to discharge the internal gas of the battery shell 112 when the end is exposed to the outside and the internal pressure of the battery shell 112 is higher than a predetermined pressure, wherein at least one exhaust portion 112a is provided in the shell 120, and the gas discharged from the exhaust portion 112b is discharged to the outside through the at least one exhaust portion.

[0058] First, the secondary battery 110 may be configured such that an electrode assembly 111 is accommodated in a battery case 112 whose edges are sealed, and may have various structures.

[0059] Here, the electrode assembly 111 may be configured such that the electrode and the separator are stacked and may have various structures. For example, the electrode assembly 111 may have a structure in which the positive electrode collector / positive electrode active material layer / separator / negative electrode active material layer / negative electrode collector are stacked in sequence so that the positive electrode active material disposed on one surface of the separator faces the negative electrode active material disposed on the other surface of the separator. Here, it is noted that the electrode assembly 111 is housed in the battery case 112 and is indicated by a dotted line in the drawing.

[0060] The electrode assembly 111 may be accommodated together with an electrolyte in a battery case 112. Here, the battery case 112 may be configured such that an edge thereof is sealed and may have various structures.

[0061] The battery case 112 may be configured such that the edge of the battery case 112 is folded to reduce the volume of the secondary battery 110 or to improve the sealing force of the battery case 112 , thereby improving energy density.

[0062] At least one discharge portion 112b and folded portion 112a may be provided at the edge of the battery case 112 to discharge gas to a designated location when gas is generated in the battery case 112 due to fire of the secondary battery 110. Here, a detailed description of the discharge portion 112b and the folded portion 112a will be described later.

[0063] The secondary battery 110 may further include an electrode lead 113 protruding from at least one end of the battery case 112. Here, the electrode lead 113 may be understood as a configuration in which one end is connected to the electrode assembly 111 inside the battery case 112 and the other end is electrically connected to an external electrical device and / or the secondary battery 110.

[0064] A plurality of the above-described secondary batteries 110 may be stacked and accommodated in the housing 120. Here, the housing 120 may be a configuration in which an accommodation space for accommodating the plurality of secondary batteries 110 is defined, and may have various structures.

[0065] Here, the housing 120 may be provided with at least one exhaust portion 122a capable of exhausting the gas ejected from the secondary battery 110 accommodated in the accommodation space to the outside. Here, the exhaust portion 122a may be a configuration capable of releasing the gas to the outside at the time when the gas is generated in the secondary battery 110, and may have an effect of preventing the internal pressure of the secondary battery module 100 from increasing.

[0066] The exhaust part 122a may be a configuration for exhausting the gas exhausted from the exhaust part 112b to the outside, and may have various structures. For example, the exhaust part 122a may be provided as a hole structure penetrating the inside and the outside of the housing 120.

[0067] In addition, the exhaust portion 122a may be provided at various positions in the housing 120. Here, the user may selectively set the position of the exhaust portion 122a so that the gas is guided to be discharged to a designated position, thereby minimizing the risk of fire.

[0068] Here, when the exhaust portion 122a is provided in the upper portion of the housing 120, there is a problem that as foreign matter or water falls from the outside, the foreign matter or water easily penetrates into the housing 120 through the exhaust portion 122a. In addition, when the exhaust portion 122a is provided in the lower portion of the housing 120, it may be difficult to ensure a gas discharge passage. Therefore, it may be preferable that the exhaust portion 122a is provided in the side portion of the housing 120.

[0069] In order to explain the formation position of the exhaust portion 122a in more detail, the structure of the housing 120 will be described first.

[0070] like Figure 1 As shown, the housing 120 may include a support frame 121 that supports the stack of secondary batteries 110 , and a pair of end plates 122 that are coupled to the support frame 121 and disposed on the front and rear surfaces of the stack of secondary batteries 110 .

[0071] Here, the support frame 121 may be a configuration for supporting the secondary battery 110 and may have various structures. For example, the support frame 121 may have a Figure 1 The U-shaped structure shown in the figure supports the lower and side portions of the secondary battery 110. However, the shape of the support frame 121 is not limited thereto and may be replaced with a frame having another shape, such as a single body frame covering the remaining four surfaces of the secondary battery 110 except for the edges from which the electrode leads 113 protrude.

[0072] In addition, if Figure 1 As shown, a cover frame 123 may be additionally disposed on an upper portion of the opening of the support frame 121. The cover frame 123 may be coupled to an upper portion of the support frame 121 and may be disposed above the secondary battery 110 to define an accommodation space of the case 120 together with the support frame 121.

[0073] The pair of end plates 122 may be a configuration coupled to the support frame 121 and disposed on the front and rear surfaces of the plurality of secondary batteries 110, and may have various structures. Here, the front and rear surfaces of the plurality of secondary batteries 110 may be understood as surfaces disposed in a direction in which the electrode lead 113 protrudes from the secondary battery 110.

[0074] Specifically, each end plate 122 may be coupled to the support frame 121 by welding or bolting. Here, the bus bar assembly 140 may be additionally disposed between the end plate 122 and the secondary battery 110. Therefore, the end plate 122 may protect the bus bar assembly 140 and various electrical components connected thereto from external impact.

[0075] Here, the bus bar assembly 140 may include a plurality of conductive bus bars and a bus bar frame supporting the bus bars, and the bus bars may be disposed to contact the electrode leads 113 protruding from the secondary batteries 110 .

[0076] The end plate 122 may include: a body made of a metal material, which protects the bus bar assembly 140, other electrical components and the secondary battery 110 from external impact; and an insulating cover coupled to the body and made of an insulating material, which maintains insulation from the bus bar assembly 140, other electrical components and the secondary battery.

[0077] At least one or more exhaust portions 122a may be formed in the end plate 122. Figure 1 As shown, the end plate 122 may have a shape along the arrangement direction of the plurality of secondary batteries 110 (with Figure 1 The structure extending in the longitudinal direction (direction parallel to the Y axis in the figure) makes the end plate 122 be arranged to face one surface of each of all the secondary batteries 110 arranged side by side. Here, one surface of the secondary battery 110 can be understood as a surface on which the electrode lead 113 protrudes.

[0078] Therefore, when the exhaust portion 122a is formed in the end plate 122, the gas can be quickly discharged to the outside regardless of where the secondary battery generating the gas is disposed among the plurality of secondary batteries 110. As a result, the plurality of secondary batteries 110 can discharge the gas sequentially rather than simultaneously, thereby preventing explosion and controlling the fire rate at the module level.

[0079] Furthermore, when the exhaust portion 122 a is formed in the end plate 122 , the exhaust portion 122 a may be provided in the side of the housing 120 to prevent foreign matter dropped from above from penetrating and to easily form a gas exhaust path.

[0080] At least one or more exhaust portions 122a may be provided in the end plate 122. For example, Figure 2 and Figure 3As shown, two exhaust portions 122 a may be provided in the end plate 122 .

[0081] Here, the vent 122a may be provided at any position of the end plate 122. However, the vent 122a may guide the gas to a portion which is insulated due to the module structure or where the risk of sparks is small, and therefore, it may be preferable to effectively control the propagation speed after the secondary battery 110 catches fire at the module level.

[0082] Specifically, the end plate 122 may be disposed to face the electrode lead 113 of the secondary battery 110 , but even in this case, it may be preferable that the vent 122 a is disposed to be spaced apart from the electrode lead 113 as much as possible.

[0083] This is because the electrode lead 113 is electrically connected to the electrode assembly 111 inside the battery case 112 and the external electrical device or the secondary battery 110, and therefore, there is a problem of rapid ignition due to sparks generated when the gas inside the housing 120 is discharged to the outside and passes close to the electrode lead 113. Therefore, there is a high possibility that an external short circuit occurs in the secondary battery module 100 and the thermal runaway propagation between the plurality of secondary batteries 110 is accelerated.

[0084] Therefore, if Figure 4 As shown, on the end plate 122 disposed facing the electrode lead 113, the exhaust portion 122a may be disposed at a position facing the battery case 112 instead of the electrode lead 113. Therefore, when gas is generated in the internal accommodation space of the secondary battery module 100, by discharging the gas to the outside before moving toward the electrode lead 113, the generation of flames due to sparks can be minimized. In this case, the occurrence of a double-wire grounding fault can be prevented, and the progress of thermal runaway propagation between the plurality of secondary batteries 110 can be suppressed and delayed.

[0085] Here, in Figure 4 In the example, the bus bar assembly 140 is illustrated on one side of the vent 122a. Here, the bus bar assembly 140 may be a configuration that avoids the vent 122a between the end plate 122 and the secondary battery 110, so it is noted that the bus bar assembly 40 is not a configuration that closes the vent 122a. This may also be applied to the following Figure 5 .

[0086] The vent portion 122 a may have various structures capable of discharging gas inside the secondary battery module 100 to the outside. For example, the vent portion 122 a may be provided as a hole structure penetrating the inside and the outside of the end plate 122 .

[0087] Here, the exhaust portion 122a may be configured as a stepped hole structure inside the end plate 122. In more detail, as Figure 4As shown, the exhaust portion 122 a may have a stepped hole structure that expands outward from the interior of the end plate 122 .

[0088] In this case, in the stepped hole structure of the vent 122a, a region having a relatively wide diameter and a structure open to the outside can be used as a region into which a jig for transferring or fixing the secondary battery module 100 is inserted. Here, an end of the jig can be fixed to contact an inner wall 122a′ provided due to the stepped portion in the vent 122a, so that the jig can easily transfer and fix the secondary battery module 100 without interfering with the internal secondary batteries 110.

[0089] The secondary battery module 100 according to the present invention may further include a cover 150 attached to the housing 120 to correspond to the position of the vent 122a. Here, a double-sided tape or the like may be interposed between the cover 150 and the housing 120 to fix the cover 150 to the housing 120.

[0090] Specifically, the cover 150 may seal the vent 122a when the internal pressure of the accommodation space is less than a predetermined pressure, and may rupture to open the vent 122a when the internal pressure of the accommodation space is higher than the predetermined pressure.

[0091] The cover 150 may be disposed at any position as long as the cover 150 covers the exhaust portion 122 a. Here, when the exhaust portion 122 a has a stepped hole structure inside the end plate, the cover 150 may be disposed inside the end plate 122 .

[0092] Specifically, if Figure 5 As shown, the cover 150 can be fixed by attaching its edge to the inner wall 122a' provided by the stepped portion in the vent 122a. In this case, the cover 150 can be disposed inside the end plate 122 and protected from external impact to minimize the occurrence of problems such as damage or separation from the fixed position.

[0093] The cover 150 may be made of a porous material. Therefore, the cover 150 may have the effect of discharging the gas inside the housing 120 to the outside and preventing moisture or foreign matter from penetrating into the housing 120.

[0094] The above-mentioned exhaust portion 122a can be preferably arranged at a position corresponding to the exhaust portion 112b of the battery case 112 according to the present invention, so that the gas exhausted from the secondary battery 110 is quickly exhausted to the outside. Hereinafter, the detailed structure of the folding portion 112a and the exhaust portion 112b of the battery case 112 according to the present invention will be described.

[0095] like Figure 6As shown, the battery case 112 according to the present invention may include: at least one folding portion 112a, which is folded so that the end of its edge is surrounded inwardly; and at least one discharge portion 112b, through which the end of the edge is exposed to the outside.

[0096] Therefore, when a predetermined amount of gas is generated inside the battery housing 112, the gas can be discharged preferentially from the discharge portion 112b, which is relatively easier to discharge gas than the folded portion 112a. Therefore, in the battery housing 112 having the above structure, the user can discharge the gas to a designated location by selectively setting the discharge portion 112b on the battery housing 112 to minimize the risk caused by the secondary battery 110 catching fire.

[0097] First, the folded portion 112 a may be a configuration that is folded so that the end of the edge of the battery case 112 is surrounded inwardly, and may have various structures.

[0098] Specifically, Figure 7 As shown, the folded portion 112a may be provided at the edge of the battery case 112, and may have a structure in which an end portion 112aa of the folded portion 112a is surrounded by folding inner surfaces facing each other.

[0099] Therefore, the folded portion 112a can have a structure in which it is relatively more difficult to discharge gas than the discharge portion 112b whose end is exposed to the outside, because the end 112aa through which the gas is discharged to the outside is surrounded inwardly, and can therefore be understood as a configuration that guides the gas to be discharged to the discharge portion 112b.

[0100] In addition, the folded portion 112 a may have a structure in which external moisture or air is relatively more difficult to penetrate because the end portion 112 aa is surrounded inwardly, and thus may be understood as a configuration that improves the sealing force of the battery case 112 .

[0101] The folded portion 112a may have any structure as long as the end portion 112aa is surrounded inwardly. For example, the folded portion 112a may have a structure in which the end portion 112aa is folded at least twice in one direction so that the end portion 112aa is surrounded inwardly at the edge of the battery case 112.

[0102] In addition, the folded portion 112 a may be provided with a structure in which inner surfaces of the folded portion 112 a contact each other or are adjacent to each other to prevent the gas from moving as much as possible even if the gas flows into the folded portion 112 a .

[0103] The adhesive member may be attached to the outside of the folded portion 112a. The adhesive member may fix the folded portion 112a folded inwardly so that the folded portion 112a is maintained in its folded shape. Here, the adhesive member may be an insulating tape or the like. When the adhesive member is attached to the outside of the folded portion 112a, the folded portion 112a may be stressed to maintain the inwardly folded shape, and may be more difficult to discharge gas than the discharge portion 112b whose end is exposed to the outside. That is, the adhesive member may guide the gas to be discharged to the discharge portion 112b more effectively.

[0104] The present invention may include a discharge portion 112 b whose sealing is released when the internal pressure of the battery case 112 is higher than a predetermined pressure so that the gas inside the battery case 112 is discharged.

[0105] Specifically, if Figure 8 As shown, the discharge portion 112 b may be provided at the edge of the battery case 112 , and may have a structure in which an end portion 112 ba of the discharge portion 112 b is exposed to the outside.

[0106] Therefore, when compared with the folded portion 112a whose ends are surrounded inward, the discharge portion 112b can have a structure that is relatively easy to discharge gas, because the end 112ba through which the gas is discharged to the outside is exposed to the outside, and therefore, the discharge portion 112b can be understood as a configuration that operates preferentially than the above-mentioned folded portion 112a to serve as a gas discharge channel when gas is generated in the battery housing 112.

[0107] The discharge portion 112b may have any structure as long as the end portion 112ba is exposed to the outside. For example, the discharge portion 112b may have a structure that is folded at least once so that the end portion 112ba is exposed to the outside. Here, the discharge portion 112b may be folded in the opposite direction to the folded portion 112a, or may be folded less times than the folded portion 112a.

[0108] Furthermore, preferably, the discharge portion 112b has a gap between inner surfaces of the discharge portion 112b folded to face each other, which is larger than a gap between inner surfaces of the folded portion 112a facing each other, to maximize movement of gas when the gas flows into the discharge portion 112b.

[0109] like Figure 8 As shown, when no gas is generated inside the battery case 112 or when the gas pressure inside the battery case 112 is less than a predetermined pressure, the discharge portion 112 b may be maintained in a sealed state.

[0110] In addition, if Fig. 9As shown, even when gas is generated inside the battery case 112 and the internal pressure of the battery case 112 reaches a predetermined pressure or more, the seal of the discharge portion 112 b can be released to guide the gas to be discharged, thereby reducing the internal pressure of the battery case 112 .

[0111] Regarding the manufacturing process, in the present invention, the folding directions of the folding portion 112a and the discharge portion 112b are different from each other. Therefore, it may be necessary to separate the folding portion 112a from the discharge portion 112b so that the folding portion 112a and the discharge portion 112b are folded in different directions. Specifically, after the position corresponding to the folding portion 112a and the position corresponding to the discharge portion 112b are sealed, the portion between the folding portion 112a and the discharge portion 112b can be cut so that the position corresponding to the folding portion 112a and the position corresponding to the discharge portion 112b are folded independently of each other. Here, the cutting method can be changed, and the sealing state of the cut portion can be maintained. The portion between the folding portion 112a and the discharge portion 112b can be cut so that the folding portion 112a and the discharge portion 112b are folded independently in different directions.

[0112] The discharge portion 112 b may be provided in the battery case 112 in various ways.

[0113] However, as described above, the secondary battery 110 according to the present invention may further include an electrode lead 113 protruding from at least one end of the battery case 112. In this case, preferably, the discharge part 112b is provided at a position away from the electrode lead 113.

[0114] Since the electrode lead 113 is electrically connected to the electrode assembly 111 inside the battery case 112 and the external electrical device or the secondary battery 110, sparks may be generated when gas discharged from the discharge portion 112b is discharged at a position adjacent to the electrode lead 113, resulting in rapid ignition.

[0115] Therefore, if Figure 6 to Figure 7 As shown, when the electrode lead 113 protrudes from at least one end of the battery case 112, preferably, the discharge portion 112b is provided on the remaining ends except the end from which the electrode lead 113 protrudes. Here, the folded portion 112a may also be provided on the remaining ends except the end from which the electrode lead 113 protrudes.

[0116] The discharge portion 112 b may be provided in various numbers and positions on the battery case 112 in consideration of the amount of gas generated inside the battery case 112 .

[0117] As an example, the discharge portion 112b may be provided as one piece and disposed at the center of the edge of the battery case 112. As another example, the discharge portion 112b may be formed in a plurality spaced apart from each other along the longitudinal direction of the battery case 112. In this case, the discharge portion 112b may be provided between the plurality of folded portions 112a.

[0118] The folding portion 112a and the discharge portion 112b may have different manufacturing processes, so that when the internal pressure of the battery housing 112 is higher than a predetermined pressure, the gas is discharged to the discharge portion 112b. Specifically, the sealing strength at the position where the discharge portion 112b is arranged may be less than the sealing strength at the position where the folding portion 112a is arranged. More specifically, the folding portion 112a may be sealed thicker than the discharge portion 112b. Therefore, when the internal pressure of the battery housing 112 is higher than a predetermined pressure, the gas may be discharged to the outside of the battery housing 112 through the discharge portion 112b having relatively poor sealing properties.

[0119] The secondary battery 110 according to the present invention may further include a film portion 160 folded to surround an end portion of the discharge portion 112 b .

[0120] Specifically, if Figure 10 to Figure 11 As shown, the film portion 160 may be configured such that both ends thereof are connected to the discharge portion 112 b and folded to surround the ends of the discharge portion 112 b , and may have various structures.

[0121] In more detail, Fig.10 As shown, when the discharge portion 112 b is in a sealed state when the internal pressure of the battery case 112 is less than a predetermined pressure, the film portion 160 may have a folded structure to surround a distal end portion of the discharge portion 112 b.

[0122] Here, when the discharge portion 112b is in a sealed state even when the seal of the discharge portion 112b is released so that both ends of the membrane portion 160 remain connected to the discharge portion 112b, the membrane portion 140 can be set so that the folded portion in the membrane portion 160 is spaced apart from the end of the discharge portion 112b by a predetermined distance.

[0123] like Fig.11 As shown, when the internal pressure of the battery case 112 is higher than a predetermined pressure and the sealing of the discharge portion 112 b is released, both ends of the film portion 140 may be deployed in a state of being connected to the outer surface of the discharge portion 112 b.

[0124] The membrane portion 160 may be made of a porous material. Therefore, when the seal of the discharge portion 112b is released, the gas inside the battery case 112 may be discharged to the outside, and at the same time, external moisture or foreign matter may be prevented from being introduced into the battery case 112. More specifically, the membrane portion 160 may be made of a thin film in which a large number of small pores are defined by heating and stretching a Teflon-based resin. Therefore, particles such as moisture that penetrate from the outside may not penetrate the membrane portion 160, but the gas generated inside may fully penetrate the membrane portion 160 to be discharged to the outside. In addition, the membrane portion 160 may be connected to the discharge portion 112b in various ways. For example, as Fig.10 and Fig.11 As shown, the film portion 160 may be connected to the discharge portion 112b by interposing an adhesive material 160' between the inner surface of the film portion 160 and the outer surface of the discharge portion 112b. The adhesive material 160' may bond the film 160 to the discharge portion 112b by heat fusion or the like.

[0125] The present invention can guide the gas generated inside the battery housing 112 to be discharged outside the housing 120 along a desired path. Therefore, the risk of a large amount of gas inside the secondary battery module 100 can be more effectively handled. In addition, in the case of thermal runaway in which a large amount of gas is generated inside the secondary battery module 100 due to a fire, a relatively effective response can also be performed. That is, the stability of the secondary battery module 100 can be improved for problems caused by internal gas.

[0126] While embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

[0127] While embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

[0128] [reference numerals list]

[0129] 100: Secondary battery module

[0130] 110: Secondary battery

[0131] 111: Electrode assembly

[0132] 112: Battery housing

[0133] 112a: Folding part

[0134] 112aa: End of folded portion

[0135] 112b: Discharge Department

[0136] 112ba: End of the discharge section

[0137] 113: Electrode lead

[0138] 120: Shell

[0139] 121: Support frame

[0140] 122: End plate

[0141] 122a: Exhaust

[0142] 122a': Inner wall of exhaust part

[0143] 123: Cover frame

[0144] 140: Busbar assembly

[0145] 150: cover

[0146] 160: Membrane

[0147] 160′: Adhesive material

Claims

1. A secondary battery module, comprising: a plurality of secondary batteries in which the electrode assembly is accommodated in a battery case whose edges are sealed; as well as a housing having a housing space in which the plurality of secondary batteries are housed, Wherein, the battery housing comprises: at least one folded portion located on the edge, the at least one folded portion being folded so that ends thereof are surrounded inwardly; and at least one discharge portion located on the edge, in which the seal is released to discharge the internal gas of the battery case when the end is exposed to the outside and the internal pressure of the battery case is higher than a predetermined pressure, Wherein, at least one exhaust portion is provided in the housing, and the gas exhausted from the exhaust portion is exhausted to the outside through the at least one exhaust portion.

2. The secondary battery module according to claim 1, wherein: The exhaust portion has a hole structure penetrating the inside and the outside of the housing.

3. The secondary battery module according to claim 1, wherein: The exhaust portion is disposed in a side portion of the housing.

4. The secondary battery module according to claim 1, wherein: The housing comprises: a supporting frame configured to support a stack of secondary batteries; and a pair of end plates coupled to the support frame and disposed on front and rear surfaces of the plurality of secondary batteries, Wherein, the exhaust portion is arranged in the end plate.

5. The secondary battery module according to claim 4, wherein: Each of the secondary batteries includes an electrode lead protruding from the battery case, The end plate is disposed to face the electrode lead, and The vent portion is provided at a position facing the battery case.

6. The secondary battery module according to claim 4, wherein: The exhaust portion has a stepped hole structure inside the end plate.

7. The secondary battery module according to claim 6, wherein: The exhaust portion gradually expands from the inside of the end plate to the outside.

8. The secondary battery module according to claim 1, further comprising a cover portion attached to the housing to correspond to a position of the vent portion, in, The cover is configured to seal the exhaust portion when the internal pressure of the accommodation space is less than the predetermined pressure, and When the internal pressure of the accommodation space is equal to or greater than the predetermined pressure, the cover portion is ruptured to open the exhaust portion.

9. The secondary battery module according to claim 8, wherein: The cover is made of porous material.

10. The secondary battery module according to claim 1, wherein: The discharge portion is folded at least once so that an end portion of the discharge portion is exposed to the outside.

11. The secondary battery module according to claim 10, wherein: The folded portion is folded at least twice, and The discharge portion is folded in an opposite direction to the folded portion.

12. The secondary battery module according to claim 10, wherein: The discharge portion is folded less times than the folded portion.

13. The secondary battery module according to claim 10, wherein: A gap between inner surfaces disposed to face each other in the discharge portion by the folding is larger than a gap between inner surfaces disposed to face each other in the folded portion by the folding.

14. The secondary battery module according to claim 1, further comprising an electrode lead protruding from at least one end portion of the battery case, in, The discharge portion is provided on the remaining end portions except for the end portions from which the electrode lead protrudes.

15. The secondary battery module according to claim 14, wherein: The folded portion is provided on the remaining end portions except for the end portions from which the electrode lead protrudes.

16. The secondary battery module according to claim 1, wherein: The discharge portion is provided as a plurality of discharge portions spaced apart from each other in the longitudinal direction of the battery case, and The discharge portion is disposed between the plurality of folded portions. 17 . The secondary battery module according to claim 1 , further comprising a film portion folded so that both ends thereof are connected to the discharge portion to surround an end of the discharge portion.

18. The secondary battery module according to claim 17, wherein: When the pressure inside the battery case is equal to or greater than the predetermined pressure, both end portions of the film portion are expanded in a state of being connected to the outer surface of the discharge portion to release the sealing of the discharge portion.

19. The secondary battery module according to claim 17, wherein: The membrane portion is made of a porous material.

20. The secondary battery module according to claim 1, wherein The secondary battery further includes an adhesive member attached to an outer side of the folded portion so that the folded portion is maintained in a folded shape.

21. The secondary battery module according to claim 1, wherein: In the secondary battery, a sealing strength of the folded portion is greater than a sealing strength of the discharge portion.

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