Secondary battery module

Abstract

The present invention relates to a secondary battery module, and more particularly, to a secondary battery module including a plurality of secondary batteries. The present invention includes a plurality of secondary batteries in which electrode assemblies are accommodated in a battery case with sealed edges, and a housing in which an accommodation space for accommodating the plurality of secondary batteries is formed. The battery case includes at least one folding portion folded at the edge such that the end is wrapped inside, and at least one exhaust portion at the edge where the end is exposed outside, and when the internal pressure of the battery case becomes a predetermined pressure or more, the seal is released and the gas inside the battery case is discharged. The housing provides a secondary battery module in which at least one venting portion for venting the gas discharged from the exhaust portion to the outside is formed.

Description

Technical Field

[0001] This application claims the benefit of priority based on 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, and all the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference in their entirety.

[0002] 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

[0003] Recently, secondary batteries have attracted attention as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), etc., which are presented as a way to solve air pollution such as existing gasoline vehicles and diesel vehicles that use fossil fuels.

[0004] One or two to three secondary batteries are used for small mobile devices, while for medium and large-sized devices such as electric vehicles, due to the need for high power and large capacity, a secondary battery module in which a number of secondary batteries are electrically connected or a secondary battery pack in which a plurality of secondary battery modules are electrically connected to each other is used.

[0005] Currently, one of the most spotlighted secondary batteries among commercially available secondary batteries is the lithium secondary battery. The lithium secondary battery can be divided into a can type, a square type, a pouch type, etc. according to the shape of the exterior material. Among these, the pouch type secondary battery is widely used in medium and large-sized battery modules because of its advantages of high energy density and easy stacking.

[0006] On the one hand, in recent years, as the demand for secondary battery modules installed in vehicles has increased, customers' needs for stability have been gradually increasing. However, customers are demanding to increase the energy density of secondary batteries within the limited space of secondary battery modules. In this case, however, there is a problem that the stability risks related to the ignition and explosion of secondary batteries both increase.

[0007] In particular, a pouch-type secondary battery has a structure in which an electrode assembly is housed in a pouch-type battery case and the edge of the battery case is sealed. When the secondary battery catches fire and the temperature of the secondary battery rises, and the electrolytic solution vaporizes inside the battery case to generate gas, the gas tends to jet out from a portion where the seal of the battery case is weak without passing through a predetermined path.

[0008] Here, when gas jets out at the adjacent position of the electrode lead or busbar, a fatal problem may occur in which ignition of the secondary battery occurs suddenly due to a spark. Also, when the gas ejected from the secondary battery accumulates inside the module housing, a problem of increased module pressure resistance may occur.

[0009] Therefore, it is a situation where the development of a technology for solving the above problems is necessary.

Summary of the Invention

Problems to be Solved by the Invention

[0010] The present invention has been derived to solve the above problems, and an object of the present invention is to provide an invention related to a secondary battery module that can minimize the ignition risk by guiding the gas ejected from the secondary battery to a designated position when an abnormal situation such as ignition of the secondary battery occurs.

Means for Solving the Problems

[0011] The present invention provides a secondary battery module including a plurality of secondary batteries in which an electrode assembly is accommodated in a battery case with a sealed edge, and a housing in which an accommodation space for accommodating the plurality of secondary batteries is formed. The battery case includes at least one folding portion folded at the edge so that a terminal is wrapped inside, and at least one exhaust portion at the edge where the terminal is exposed outside, and when the internal pressure of the battery case becomes a predetermined pressure or more, the seal is released and the internal gas of the battery case is discharged. The housing is formed with at least one venting portion through which the gas discharged from the exhaust portion is vented to the outside.

[0012] The venting portion can be a hole structure penetrating the housing.

[0013] The venting portion can be provided on a side portion of the housing.

[0014] The housing includes a support frame for supporting a stack of the secondary batteries, and a pair of end plates coupled to the support frame and positioned on the front and rear surfaces of the plurality of secondary batteries. The venting portion can be formed on the end plate.

[0015] The secondary battery includes an electrode lead protruding from the battery case. The end plate is disposed to face the electrode lead, and the venting portion can be provided at a position facing the battery case.

[0016] The venting portion can be formed in a stepped hole structure inside the end plate.

[0017] The venting portion can expand from the inside to the outside of the end plate.

[0018] The housing further includes a cover portion attached to the housing corresponding to the position of the bending portion. When the internal pressure of the accommodation space is less than a predetermined pressure, the cover portion seals the bending portion. When the internal pressure of the accommodation space is equal to or greater than the predetermined pressure, the cover portion ruptures to open the bending portion.

[0019] The cover portion can be made of a porous material.

[0020] The exhaust portion can be folded at least once so that the end is exposed to the outside.

[0021] The folding portion is folded at least twice in one direction, and the exhaust portion can be folded in a direction opposite to that of the folding portion.

[0022] The exhaust portion can be folded fewer times than the folding portion.

[0023] The exhaust portion can be formed such that the distance between the inner surfaces provided to face each other by folding is larger than the distance between the inner surfaces provided to face each other by folding in the folding portion.

[0024] On the other hand, the battery case further includes an electrode lead protruding from at least one end portion thereof, and the exhaust portion can be formed at the remaining end portion other than the end portion where the electrode lead protrudes.

[0025] The folding portion can be formed at the remaining end portion other than the end portion where the electrode lead protrudes.

[0026] A plurality of the exhaust portions are formed at intervals along the longitudinal direction of the battery case, and the exhaust portions can be provided between the plurality of folding portions.

[0027] On the one hand, the secondary battery module according to the present invention can further include a membrane portion that is folded such that both ends are connected to the exhaust portion and wrap the end of the exhaust portion.

[0028] When the internal pressure of the battery case is equal to or higher than a predetermined pressure and the exhaust portion is unsealed, the membrane portion can be deployed with both ends connected to the outer surface of the exhaust portion.

[0029] The membrane portion can be made of a porous material.

[0030] The secondary battery can further include an adhesive member attached to the outside of the folding portion so that the folded shape of the folding portion is maintained.

[0031] The secondary battery can have a sealing strength of the folding portion stronger than that of the exhaust portion.

Advantages of the Invention

[0032] The present invention has the effect of preventing an increase in the pressure resistance of the module by forming a venting portion in the housing and exhausting the gas generated from the secondary battery to the outside of the housing.

[0033] In addition, the present invention has the effect of minimizing the penetration of external foreign substances into the housing and easily securing a gas discharge path by forming the venting portion on the side portion of the housing.

[0034] Furthermore, the present invention further includes a cover portion provided corresponding to the position of the venting portion and sealing the venting portion when the internal pressure of the accommodation space is less than a predetermined pressure, thereby minimizing the penetration of external foreign substances into the housing and easily discharging the gas when the pressure resistance of the module increases.

[0035] In addition, the present invention provides an exhaust portion at the edge of the battery case with its end exposed to the outside, and by guiding the gas generated inside the battery case to diverge to a specified position, the risk of ignition can be minimized.

[0036] Furthermore, the present invention further includes a membrane portion connected to the exhaust portion, which can discharge the gas inside the battery case and prevent external moisture or foreign substances from penetrating into the battery case.

[0037] Thereby, the stability of the secondary battery module in the thermal runaway situation can be improved.

Brief Description of the Drawings

[0038]

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0039] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be realized in various different forms and is not limited or restricted by the following embodiments.

[0040] To clearly explain the present invention, detailed descriptions of parts not related to the explanation or related known technologies that may obscure the gist of the present invention are omitted. When assigning reference numerals to the components of each drawing in this specification, the same or similar reference numerals are assigned to the same or similar components throughout the specification.

[0041] Also, the terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings. The inventors should interpret them in accordance with the meaning and concept that conform to the technical idea of the present invention, in accordance with the principle that they can appropriately define the concept of the terms in order to explain their invention in the best way.

[0042] The present invention provides a secondary battery module 100 including a plurality of secondary batteries 110 in which an electrode assembly 111 is housed in a battery case 112 with a sealed edge, and a housing 120 in which a housing space for housing the plurality of secondary batteries 110 is formed. The battery case 112 includes at least one folding portion 112a folded at the edge so that the end is wrapped inside, and at least one exhaust portion 112b in which the end is exposed outside at the edge and the seal is released when the internal pressure of the battery case 112 becomes a predetermined pressure or more, and the internal gas of the battery case 112 is discharged. The housing 120 is formed with at least one venting portion 122a through which the gas discharged from the exhaust portion 112b is exhausted to the outside.

[0043] First, the secondary battery 110 has a configuration in which an electrode assembly 111 is housed in a battery case 112 with a sealed edge, and can have various structures.

[0044] Here, the electrode assembly 111 has a configuration in which an electrode and a separator are laminated, and can have various structures. For example, the electrode assembly 111 can have a structure in which a positive electrode current collector / positive electrode active material layer / separator / negative electrode active material layer / negative electrode current collector are laminated in this order, and the positive electrode active material layer on one side of the separator faces the negative electrode active material layer on the other side. Here, note that in the drawing, the electrode assembly 111 is configured to be housed inside the battery case 112 and is represented by a dotted line.

[0045] Such an electrode assembly 111 can be housed in the battery case 112 together with an electrolytic solution. Here, the battery case 112 has a configuration with a sealed edge and can have various structures.

[0046] The above battery case 112 can be provided with the edge of the battery case 112 folded in order to reduce the volume of the secondary battery 110 or to further improve the sealing force of the battery case 112 for improving the energy density.

[0047] Further, at least one exhaust portion 112b and folding portion 112a can be formed at the folded edge of the battery case 112 so that when gas is generated inside the battery case 112 due to ignition of the secondary battery 110 or the like, the gas can be discharged to a designated position. Specific descriptions regarding the exhaust portion 112b and folding portion 112a will be described later.

[0048] Such a secondary battery 110 can further include an electrode lead 113 that protrudes from at least one end of the battery case 112. Here, it can be understood that one end of the electrode lead 113 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.

[0049] On the other hand, a plurality of the above-described secondary batteries 110 can be stacked and accommodated in the housing 120. Here, the housing 120 is configured to have an accommodation space for accommodating the plurality of secondary batteries 110 inside, and can have various structures.

[0050] Here, at least one or more venting portions 122a can be provided in the housing 120 to discharge the gas ejected from the secondary battery 110 accommodated in the accommodation space to the outside. Here, the venting portion 122a is configured to discharge the gas to the outside at the moment when gas is generated in the secondary battery 110, and has the effect of preventing an increase in the pressure resistance of the secondary battery module 100.

[0051] Such a venting portion 122a is configured to exhaust the gas discharged from the above-described exhaust portion 112b to the outside, and can have various structures. For example, the venting portion 122a can be formed in a hole structure that penetrates the housing 120.

[0052] In addition, the bending portion 122a can be provided at various positions in the housing 120. Here, the user can selectively form the position of the bending portion 122a to guide the gas to diverge to a specified position, thereby minimizing the risk of ignition.

[0053] Here, when the bending portion 122a is formed at the upper part of the housing 120, there may be a problem that foreign matter and water penetrate into the housing 120 through the bending portion 122a due to the fall of foreign matter and water from the outside. Also, when the bending portion 122a is formed at the lower part of the housing 120, it may be difficult to secure an exhaust passage for the gas. Therefore, the bending portion 122a is preferably provided at the side portion of the housing 120.

[0054] On the other hand, in order to explain in more detail the formation position of the bending portion 122a, first, the structure of the housing 120 will be specifically described.

[0055] As shown in FIG. 1, the housing 120 can include a support frame 121 that supports the laminate of the secondary battery 110, and a pair of end plates 122 that are coupled to the support frame 121 and are located on the front and rear surfaces of the laminate of the secondary battery 110.

[0056] Here, the support frame 121 is configured to support the secondary battery 110 and can have various structures. For example, as shown in FIG. 1, the support frame 121 has a U-shaped structure and can support the lower and side portions of the secondary battery 110. However, the shape of the support frame 121 is not limited thereto, and a frame of another shape such as a monoframe that covers the remaining four surfaces of the secondary battery 110 other than the corners where the electrode leads 113 protrude may be used instead.

[0057] Further, as shown in FIG. 1, a cover frame 123 can be further provided on the open upper part of the support frame 121. The cover frame 123 can be coupled to the upper part of the support frame 121, provided on the upper side of the secondary battery 110, and can form an accommodation space of the housing 120 together with the support frame 121.

[0058] On the other hand, the pair of end plates 122 are coupled to the support frame 121 and are located on the front and rear surfaces of the plurality of secondary batteries 110, and can have various structures. Here, the front and rear surfaces of the plurality of secondary batteries 110 can be understood as the surfaces provided in the direction in which the electrode leads 113 protrude in the secondary battery 110.

[0059] Specifically, the end plate 122 can be coupled to the support frame 121 by welding or bolting. Here, a bus bar assembly 140 can be further provided between the end plate 122 and the secondary battery 110. Thereby, the end plate 122 can protect the bus bar assembly 140 and various electrical components connected thereto from external impacts.

[0060] Here, the bus bar assembly 140 includes a plurality of bus bars having electrical conductivity and a bus bar frame supporting the bus bars, and the bus bar bundle can be provided to contact the electrode leads 113 protruding from the secondary battery 110.

[0061] Such an end plate 122 is made of a metal material and has a main body that protects the bus bar assembly 140, other electrical components, and the secondary battery 110 from external impacts, and an insulating cover that is coupled to the main body, made of an insulating material, and maintains insulation from the bus bar assembly 140, other electrical components, and the secondary battery 110.

[0062] On one hand, at least one or more bending portions 122a can be formed on the end plate 122. Here, as shown in FIG. 1, since the end plate 122 has a structure extending in the longitudinal direction along the arrangement direction of the plurality of secondary batteries 110 (the direction parallel to the Y-axis with reference to FIG. 1), it can be arranged so as to face any one of the surfaces of the secondary batteries 110 arranged in parallel. Here, one surface of the secondary battery 110 can be understood as the surface on which the electrode lead 113 protrudes.

[0063] Therefore, when the bending portion 122a is formed on the end plate 122, regardless of the position of the secondary battery 110 in which gas is generated among the plurality of secondary batteries 110, the gas can be quickly discharged to the outside. As a result, the plurality of secondary batteries 110 can exhaust gas sequentially instead of simultaneously, preventing explosion at the module level and controlling the ignition speed.

[0064] Also, when the bending portion 122a is formed on the end plate 122, since the bending portion 122a is provided on the side portion of the housing 120, it is possible to prevent the penetration of foreign objects falling from above, etc., and there is an advantage that a gas discharge path can be easily formed.

[0065] On one hand, at least one or more bending portions 122a can be formed on the end plate 122. For example, as shown in FIGS. 2 to 3, two bending portions 122a can be formed on the end plate 122.

[0066] Here, the bending portion 122a can be formed at any position on the end plate 122. However, the bending portion 122a is formed so as to be able to guide the exhaust of gas to a place where insulation treatment is performed or there is little risk of electric spark generation in terms of the module structure, and it is preferable to effectively control the propagation speed after the ignition of the secondary battery 110 at the module level.

[0067] In particular, the end plate 122 can be arranged to face the electrode lead 113 of the secondary battery 110. Also in this case, it is preferable that the bending portion 122a is formed at a position maximally separated from the electrode lead 113.

[0068] That is, the electrode lead 113 is configured to be electrically connected to the electrode assembly 111 inside the battery case 112 and an external electrical device or the secondary battery 110. When the gas inside the housing 120 is exhausted to the outside and passes through the proximity position of the electrode lead 113, a problem may occur where a spark is generated and ignition occurs rapidly. Therefore, in the secondary battery module 100, an external short circuit may occur, and the possibility of accelerating the thermal runaway propagation between the plurality of secondary batteries 110 becomes very high.

[0069] Therefore, as shown in FIG. 4, the bending portion 122a can be provided at a position facing the battery case 112 instead of the electrode lead 113 on the end plate 122 arranged to face the electrode lead 113. Therefore, when it occurs in the accommodation space inside the secondary battery module 100, by discharging the gas to the outside before it moves toward the electrode lead 113, the generation of flames due to sparks can be minimized. In this case, the occurrence of an external short circuit can be prevented, and there is an effect that the progress of thermal runaway propagation between the plurality of secondary batteries 110 can be suppressed and delayed.

[0070] Here, in FIG. 4, a bus bar assembly 140 is shown on one side of the bending portion 122a. Here, it should be noted that the bus bar assembly 140 is configured to avoid the bending portion 122a between the end plate 122 and the secondary battery 110, and is not configured to close the bending portion 122a. The same applies to FIG. 5 below.

[0071] On the one hand, the bending part 122a can have various structures capable of discharging the gas inside the secondary battery module 100 to the outside. For example, the bending part 122a can be formed in a hole structure penetrating the end plate 122.

[0072] Here, the bending part 122a can be formed in a stepped hole structure inside the end plate 122. More specifically, as shown in FIG. 4, the bending part 122a can have a stepped hole structure that expands from the inside to the outside of the end plate 122.

[0073] In this case, in the stepped hole structure of the bending part 122a, the region having a relatively wide diameter and an open structure facing the outside can be used as the region into which a jig for transferring or fixing the secondary battery module 100 is inserted. Here, the end of the jig can abut against and be fixed to the inner wall 122a' formed by the step in the bending part 122a, whereby it does not interfere with the internal secondary battery 110 and the secondary battery module 100 can be easily transferred and fixed.

[0074] On the other hand, the secondary battery module 100 according to the present invention can further include a cover part 150 attached to the housing 120 corresponding to the position of the bending part 122a. Here, an adhesive double-sided tape or the like can be interposed between the cover part 150 and the housing 120 to fix the cover part 150 to the housing 120.

[0075] Specifically, the cover part 150 can be understood to seal the bending part 122a when the internal pressure of the accommodation space is less than a predetermined pressure, and to rupture and open the bending part 122a when the internal pressure of the accommodation space is equal to or greater than the predetermined pressure.

[0076] The above cover portion 150 can be provided at any position as long as it covers the bending portion 122a. Here, when the bending portion 122a has a stepped hole structure inside the end plate, the cover portion 150 can be provided inside the end plate 122.

[0077] Specifically, as shown in FIG. 5, the cover portion 150 can have its edge adhered and fixed to the inner wall 122a' formed by a step in the bending portion 122a. In this case, the cover portion 150 is located inside the end plate 122 and protected from external impacts, minimizing the occurrence of damage or detachment from the fixed position.

[0078] Such a cover portion 150 can be made of a porous material. Thereby, the cover portion 150 has the effect of allowing the gas inside the housing 120 to be discharged to the outside and preventing external moisture and foreign substances from penetrating into the housing 120.

[0079] On the other hand, the above-mentioned bending portion 122a is preferably provided at a position corresponding to the exhaust portion 112b of the battery case 112 of the present invention so that the gas discharged from the secondary battery 110 can be quickly exhausted to the outside. Hereinafter, the detailed structures of the folding portion 112a and the exhaust portion 112b of the battery case 112 of the present invention will be described.

[0080] The battery case 112 according to the present invention can include at least one folding portion 112a in which the end is folded so that the end is wrapped inside at the edge, and at least one exhaust portion 112b in which the end is exposed outside at the edge, as shown in FIG. 6.

[0081] As a result, when a certain amount or more of gas is generated inside the battery case 112, the gas can be released from the exhaust portion 112b, where gas release is relatively easier than from the folding portion 112a. Therefore, in the battery case 112 having the above structure, the user can selectively arrange the exhaust portion 112b on the battery case 112 to diverge the gas to a specified position, thereby minimizing the risk of ignition of the secondary battery 110.

[0082] First, the folding portion 112a is configured to be folded at the edge of the battery case 112 such that the end is wrapped inside, and can have various structures.

[0083] Specifically, as shown in FIG. 7, the folding portion 112a can be provided at the edge of the battery case 112 and have a structure in which the end 112aa of the folding portion 112a is wrapped by the opposing inner surface due to folding.

[0084] As a result, the folding portion 112a has a structure in which the end 112aa from which gas can be released to the outside is wrapped inside, and it is a structure in which gas release is relatively difficult compared to the exhaust portion 112b with the end exposed to the outside, and can be understood as a configuration for guiding gas release from the exhaust portion 112b.

[0085] Also, the folding portion 112a has a structure in which the end 112aa is wrapped inside, and it can be understood as a configuration for improving the sealing force of the battery case 112 because it is relatively difficult for external moisture, air, etc. to penetrate.

[0086] The above folding portion 112a can have any structure as long as the end 112aa is wrapped inside. For example, the folding portion 112a can have a structure in which it is folded at least two or more times in one direction at the edge of the battery case 112 such that the end 112aa is wrapped inside.

[0087] Further, even if gas flows into the folding portion 112a, the folding portion 112a can be formed in a structure in which the inner surfaces facing each other are in contact with or adjacent to each other by folding so as to prevent the movement of gas to the maximum extent.

[0088] An adhesive member can be attached to the outside of the folding portion 112a. The adhesive member can fix the folding portion 112a so that the folding portion 112a folded inward maintains the folded shape. Here, the adhesive member can be an insulating tape or the like. When the adhesive member is attached to the outside of the folding portion 112a, the folding portion 112a can receive a force to maintain the folded shape inward, and gas release can be made more difficult than the exhaust portion 112b with the end exposed to the outside. That is, the adhesive member can guide the gas to be discharged from the exhaust portion 112b more efficiently.

[0089] On the other hand, the present invention can include an exhaust portion 112b that releases the seal and discharges the gas inside the battery case 112 when the internal pressure of the battery case 112 becomes a predetermined pressure or more.

[0090] Specifically, as shown in FIG. 8, the exhaust portion 112b can be provided at the edge of the battery case 112 and have a structure in which the end 112ba of the exhaust portion 112b is exposed to the outside.

[0091] Thereby, the exhaust portion 112b has a structure in which the end 112ba from which gas can be released to the outside is exposed to the outside, and gas release is relatively easier than the folding portion 112a in which the end 112ba is wrapped inside. It can be understood that the exhaust portion 112b operates prior to the above-described folding portion 112a when gas is generated inside the battery case 112 and is used as a gas release passage.

[0092] The above exhaust part 112b can have any structure as long as the end 112ba is exposed to the outside. For example, the exhaust part 112b can have a structure that is folded at least once so that the end 112ba is exposed to the outside. Here, the exhaust part 112b may be folded in a direction opposite to that of the folding part 112a, or may be folded fewer times than the folding part 112a.

[0093] Further, when gas flows into the exhaust part 112b, the exhaust part 112b is preferably formed such that the distance between the inner surfaces provided to face each other by folding, which maximally guides the movement of the gas, is larger than the distance between the inner surfaces provided to face each other by folding in the folding part 112a.

[0094] As shown in FIG. 8, such an exhaust part 112b can maintain a sealed state when no gas is generated inside the battery case 112 or when the pressure of the gas inside the battery case 112 is less than a predetermined pressure.

[0095] Further, as shown in FIG. 9, 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 exhaust part 112b is unsealed to induce the release of the gas, thereby reducing the pressure inside the battery case 112.

[0096] In relation to the manufacturing process, in the present invention, the folding directions of the folding portion 112a and the exhaust portion 112b are different. Therefore, it is necessary to perform a separation operation so that the folding portion 112a and the exhaust portion 112b can be separated and folded in different directions respectively. Specifically, after the positions corresponding to the folding portion 112a and the positions corresponding to the exhaust portion 112b are sealed, the two can be cut so that the positions corresponding to the folding portion 112a and the positions corresponding to the exhaust portion 112b can be folded independently of each other. Here, the cutting method can be various, and the sealing state of the cut portion can be maintained. The folding portion 112a and the exhaust portion 112b are cut from each other, and the folding portion 112a and the exhaust portion 112b can be folded independently in different directions from each other.

[0097] On the other hand, the exhaust portion 112b can be variously arranged in the battery case 112.

[0098] However, the secondary battery 110 according to the present invention can further include an electrode lead 113 protruding from at least one end of the battery case 112 as described above. In this case, the exhaust portion 112b is preferably formed at a position maximally separated from the electrode lead 113.

[0099] This is because the electrode lead 113 is configured to be electrically connected to the electrode assembly 111 inside the battery case 112 and an external electrical device or the secondary battery 110. When the gas discharged from the exhaust portion 112b is discharged in the vicinity of the electrode lead 113, a problem may occur in that a spark is generated and ignition occurs rapidly.

[0100] Therefore, as shown in FIGS. 6 to 7, when the electrode lead 113 protrudes from at least one end of the battery case 112, the exhaust portion 112b is preferably formed at the remaining end other than the end where the electrode lead 113 protrudes. Here, the above-described folding portion 112a can also be formed at the remaining end other than the end where the electrode lead 113 protrudes.

[0101] On the other hand, the above-described exhaust portion 112b can 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.

[0102] As an example, one exhaust portion 112b can be formed and provided at the central portion of the edge of the battery case 112. As another example, a plurality of exhaust portions 112b can be formed and provided at intervals along the longitudinal direction of the battery case 112. In this case, the exhaust portion 112b can be provided between a plurality of the folding portions 112a.

[0103] The folding portion 112a and the exhaust portion 112b can have different manufacturing processes so that gas is discharged from the exhaust portion 112b when the internal pressure of the battery case 112 reaches a predetermined pressure or more. Specifically, the sealing strength at the position where the exhaust portion 112b is formed can be lower than the sealing strength at the position where the folding portion 112a is formed. More specifically, the folding portion 112a can be sealed thicker than the exhaust portion 112b. Therefore, when the internal pressure of the battery case 112 reaches a predetermined pressure or more, gas can be discharged to the outside of the battery case 112 through the exhaust portion 112b having relatively low sealing performance.

[0104] On the other hand, the secondary battery 110 according to the present invention may further include a membrane portion 160 that is folded so as to wrap the end of the exhaust portion 112b.

[0105] Specifically, as shown in FIGS. 10 to 11, the membrane portion 160 is configured to be folded such that both ends are connected to the exhaust portion 112b and wrap the end of the exhaust portion 112b, and can have various structures.

[0106] More specifically, as shown in FIG. 10, when the internal pressure of the battery case 112 is less than a predetermined pressure and the exhaust portion 112b is in a sealed state, the membrane portion 160 can have a structure that is folded to wrap the end of the exhaust portion 112b.

[0107] Here, when the exhaust portion 112b is in a sealed state, the membrane portion 160 is folded and the folded portion is provided so as to be separated from the end of the exhaust portion 112b by a predetermined interval such that both ends are connected to the exhaust portion 112b even when the exhaust portion 112b is unsealed.

[0108] On the other hand, as shown in FIG. 11, when the internal pressure of the battery case 112 is equal to or greater than a predetermined pressure and the exhaust portion 112b is unsealed, the membrane portion 160 can have a structure that is deployed in a state where both ends are connected to the outer surface of the exhaust portion 112b.

[0109] Such a membrane part 160 can be made of a porous material. Thereby, when the exhaust part 112b is unsealed, the gas inside the battery case 112 can be released to the outside, and moisture, foreign matters, etc. from the outside can be prevented from penetrating into the battery case 112. More specifically, the membrane part 160 can be made of a thin film formed by heating and spreading a Teflon (registered trademark) - based resin, with a number of small holes formed. Therefore, particles such as moisture penetrating from the outside cannot pass through the membrane part 160, while the gas generated inside can pass through sufficiently and be discharged to the outside. Also, the membrane part 160 can be connected to the exhaust part 112b in various ways. For example, as shown in FIGS. 10 to 11, the membrane part 160 can be connected to the exhaust part 112b by an adhesive substance 160' being interposed between the inner surface of the membrane part 160 and the outer surface of the exhaust part 112b. The adhesive substance 160' can join the membrane part 160 and the exhaust part 112b by heat fusion or the like.

[0110] The present invention can guide the gas generated inside the battery case 112 to be discharged to the outside of the housing 120 along a desired path. Therefore, it is possible to deal with the risks generated inside the secondary battery module 100 more efficiently due to a large amount of gas. Also, during a thermal runaway in which a large amount of gas is generated inside the secondary battery module 100 due to a fire, similarly, relatively efficient countermeasures are possible. That is, the stability of the secondary battery module 100 can be improved against the problems caused by the internal gas.

[0111] As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereby, and various implementations are possible within the equivalent scope of the technical idea of the present invention and the claims described below by those having ordinary knowledge in the technical field to which the present invention pertains.

Explanation of Reference Numerals

[0112] 100 Secondary battery module 110 Secondary battery 111 Electrode assembly 112 Battery case 112a Folding part 112aa End of the folding part 112b Exhaust part 112ba End of the exhaust part 113 Electrode lead 120 Housing 121 Support frame 122 End plate 122a Venting part 122a' Inner wall of the venting part 123 Cover frame 140 Busbar assembly 150 Cover part 160 Membrane part 160' Adhesive substance

Claims

1. A plurality of secondary batteries in which an electrode assembly is housed in a battery case with a sealed edge portion, and a housing in which an accommodation space for housing the plurality of secondary batteries is formed inside, wherein the battery case includes at least one folding portion folded at the edge portion so that the end is wrapped inside, and at least one exhaust portion at the edge portion where the end is exposed outside, and when the internal pressure of the battery case becomes a predetermined pressure or more, the seal is released and the internal gas of the battery case is discharged, and the housing has at least one venting portion formed therein for venting the gas discharged from the exhaust portion to the outside, a secondary battery module.

2. The secondary battery module according to claim 1, wherein the venting portion is a hole structure penetrating the housing.

3. The secondary battery module according to claim 1, wherein the venting portion is provided on a side portion of the housing.

4. The housing includes a support frame for supporting the stack of the secondary batteries, and a pair of end plates coupled to the support frame and positioned in front of and behind the plurality of secondary batteries, and the venting portion is formed on the end plate, the secondary battery module according to claim 1.

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

6. The secondary battery module according to claim 4, wherein the venting portion is formed in a stepped hole structure inside the end plate.

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

8. The secondary battery module further includes a cover portion attached to the housing corresponding to the position of the venting portion, wherein the cover portion seals the venting portion when the internal pressure of the accommodation space is less than a predetermined pressure, and ruptures to open the venting portion when the internal pressure of the accommodation space is a predetermined pressure or more, the secondary battery module according to claim 1.

9. The secondary battery module according to claim 8, wherein the cover portion has a porous material.

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

11. The folding portion is folded at least twice in one direction, The secondary battery module according to claim 10, wherein the exhaust portion is folded in a direction opposite to the one direction of the folding portion.

12. The secondary battery module according to claim 10, wherein the exhaust portion is folded a smaller number of times than the folding portion.

13. The exhaust portion is The secondary battery module according to claim 10, wherein a distance between inner surfaces provided to face each other by folding is formed larger than a distance between inner surfaces provided to face each other by folding in the folding portion.

14. Further including an electrode lead protruding from at least one end of the battery case, The secondary battery module according to claim 1, wherein the exhaust portion is formed at the remaining end other than the end where the electrode lead protrudes.

15. The secondary battery module according to claim 14, wherein the folding portion is formed at the remaining end other than the end where the electrode lead protrudes.

16. A plurality of the exhaust portions are formed at intervals along the longitudinal direction of the battery case, The secondary battery module according to claim 1, wherein the exhaust portion is provided between a plurality of the folding portions.

17. The secondary battery module according to claim 1, further including a membrane portion whose both ends are connected to the exhaust portion and folded so as to wrap the end of the exhaust portion.

18. The membrane portion is The secondary battery module according to claim 17, wherein when the internal pressure of the battery case is equal to or higher than a predetermined pressure and the exhaust portion is unsealed, it is deployed in a state where both ends are connected to the outer surface of the exhaust portion.

19. The secondary battery module according to claim 17, wherein the membrane portion has a porous material.

20. The secondary battery is The secondary battery module according to claim 1, further including an adhesive member attached to the outside of the folding portion so that the shape of the folding portion after being folded is maintained.

21. The secondary battery is The secondary battery module according to claim 1, wherein the sealing strength of the folding portion is stronger than the sealing strength of the exhaust portion.

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