Explosion-proof battery module structure

Abstract

The present invention provides a battery module 1 including an expansion member 31 and a spring member 32 to prevent or delay the release of thermal energy and flames and explosion, and to prevent a chain reaction of fire between other battery modules. The expansion member 31 may be an inversion disk 31R, and the inversion disk 31R inverts its shape when the internal pressure exceeds a predetermined yield pressure that is smaller than the explosion pressure defined as the minimum pressure at which the battery module 1 can explode, thereby expanding the internal space of the battery module 1 and preventing or delaying the increase in internal pressure and explosion.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0088814 dated July 19, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery module that reduces the risk of explosion by using an expansion structure and venting structure for the internal space of the battery module. [Background technology]

[0003] Secondary batteries, which are easily applicable to various products and have electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles or hybrid vehicles powered by electrical sources, power storage devices, etc. These secondary batteries are attracting attention as a new energy source not only because they can dramatically reduce the use of fossil fuels, but also because they are environmentally friendly and produce no by-products from energy use, thereby improving energy efficiency.

[0004] While small mobile devices use one or two or three battery cells per device, medium to large devices such as automobiles require high output and large capacity, so medium to large battery modules, which electrically connect multiple battery cells, are used.

[0005] Since it is preferable that medium- to large-sized battery modules be manufactured with as small a size and weight as possible, prismatic batteries, pouch-shaped batteries, etc., which can be stacked with a high degree of integration and have a small weight relative to their capacity, are mainly used as battery cells for medium- to large-sized battery modules.

[0006] 1 and 2 are a perspective view and an exploded perspective view, respectively, of a typical battery module. Referring to these drawings, a battery module 1 may generally include a battery cell stack 2, a U-frame 41 that houses the battery cell stack 2, a pair of end plates 42 that cover the front and rear ends of the U-frame 41, and a top plate 3 that covers the top of the U-frame 41.

[0007] The battery cell stack 2 is formed by stacking a plurality of pouch-type battery cells 21, and each of the battery cells 21 may include a pair of electrode leads. The electrode leads may be connected to each other with the same pole or different poles via a bus bar, and the bus bar may be electrically connected to a terminal 5 exposed to the outside of the battery module 1 via a terminal exposure portion 51 provided on the end plate 42. This allows the battery cell stack 2 to be connected to another external battery module.

[0008] Meanwhile, there is a risk that the battery cells 21 may overheat and ignite, such as by short-circuiting. If the battery cells 21 ignite, heat, flame, and vent gas generated by vaporization of the electrolyte charged in the battery cells 21 may be emitted from the battery cells 21. The heat, flame, and vent gas may increase the internal pressure of the battery module 1, which may result in an explosion of the battery module 1. Such an explosion of the battery module may lead to personal injury, particularly in the battery of an electric vehicle located close to the passengers.

[0009] Meanwhile, as a solution to prevent the above-mentioned battery module explosion problem, a solution to reduce the internal pressure of the battery module by using a venting structure that intentionally releases heat, flames, and vent gases caused by ignition has been widely used. However, such a venting structure has the problem that flame and heat energy may be transferred between adjacent battery modules in the battery pack, causing a chain reaction of fires.

[0010] 4 and 5 are schematic diagrams showing how thermal energy and flames are transferred between battery modules. Referring to these drawings, thermal energy and flames generated by ignition of the battery cell stack 2 are mainly located in the end plates 42 and can be discharged through the terminal exposure portions 51 and the joints between the end plates 42, the top plate 3, and the U-frame 41. Because battery modules in a battery pack are often arranged adjacent to each other in the lengthwise or widthwise direction, there is a high risk of a chain reaction of fires occurring if venting is performed horizontally, as described above.

[0011] Furthermore, if the battery module 1 that was opened for venting remains open even after venting has occurred and the internal pressure of the battery module 1 has been sufficiently reduced, there is a high possibility that heat energy and flames generated from other battery modules will be transferred to the battery module 1. Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention was conceived in light of the background of the prior art as described above, and aims to provide a battery module structure that can prevent or delay an increase in internal pressure and delay the release of explosions and flames in the event of ignition.

[0013] Another object of the present invention is to provide a battery module structure that can induce venting in the event of fire to be directed vertically.

[0014] A further technical object of the present invention is to provide a battery module structure that can be further sealed after venting has occurred.

[0015] The present invention is not limited to the above-mentioned objects, and other unmentioned objects and advantages can be understood from the following description and more clearly understood from the examples of the present invention. Furthermore, it is clear that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0016] In order to solve the above problems, the present invention provides a battery module including a battery cell stack, the battery module including: a frame with an open upper portion; a top plate joined to the frame and covering the open upper portion of the frame; a spring member that presses downward to fix the top plate so that the top plate contacts the upper end of a side wall of the frame; and an expansion member provided on a part of the top plate.

[0017] The battery module may have an explosion pressure defined as the minimum internal pressure at which an explosion of the battery module can occur.

[0018] By including the expansion member and the spring member, the battery module according to the present invention can, on the one hand, delay the increase in internal pressure of the battery module when the battery cell stack ignites, and on the other hand, induce venting by releasing the top plate from the frame and opening the frame before the internal pressure of the battery module reaches the explosion pressure.

[0019] The spring member can press the top plate downward so that the top plate contacts the upper end of the side wall of the frame, thereby fixing the top plate so that the top plate covers the open upper part of the frame.

[0020] The spring member may be one or more.

[0021] The spring member may be a coil spring made of a metal material, but is not limited thereto.

[0022] The lower end of the spring member may be embedded in the upper end of the side wall of the frame. The embedded installation may be performed by insert injection, and may be performed by assembling a separate member for fixing.

[0023] In this case, the upper end of the spring member may be fixed to the top plate.

[0024] As described above, each end of the spring member may be fixed to the upper end of the side wall of the frame and the top plate, so that the spring member has a restoring force that pulls the top plate when the top plate moves away from the upper end of the side wall of the frame, thereby tending to restore the top plate to the upper end of the side wall of the frame.

[0025] Instead of the spring member, the lower end of the spring shaft may be embedded in the upper end of the side wall of the frame. In this case, the embedded installation may be performed by insert injection, and a separate member may be provided for fixing and assembled.

[0026] In this case, the spring shaft may be formed to penetrate the top plate from top to bottom, and a fixed end may be provided at an upper end of the spring shaft located above the top plate.

[0027] In this case, the spring member can be installed between the top plate and the fixed end so as to penetrate the spring shaft, i.e., the spring member can be installed such that its upper end contacts the fixed end and its lower end contacts the top plate, and is interposed between the fixed end and the top plate.

[0028] As described above, the spring member is connected to the upper end of the side wall of the frame, and the spring shaft penetrates the top plate, and a spring member is installed between the fixed end located at the upper end of the spring shaft and the top plate so as to penetrate the spring shaft.Therefore, the spring member compresses when the top plate moves away from the upper end of the side wall of the frame, and thereby has a restoring force that tends to restore the top plate to the upper end side of the side wall of the frame.

[0029] The battery module may have a pressure resistance limit defined by the maximum pressure of the battery module that can maintain the bond between the top plate and the frame.

[0030] The withstand pressure limit may be lower than the explosion pressure. Thus, if the internal pressure of the battery module reaches the withstand pressure limit before reaching the explosion pressure, the top plate is released from the frame, and the battery module is opened upward. As a result, thermal energy and vent gas generated from the battery cell stack are vented upward, reducing the withstand pressure.

[0031] The spring member may be a pre-stressed spring that is pre-tensioned or pre-compressed so as to have a predetermined restoring force even when the top plate and the frame are in complete contact with each other, and thus the pressure limit can be defined as the minimum internal pressure at which further tension or compression occurs in the spring member.

[0032] The top plate and the frame may be connected and joined to each other by a further fixing member in addition to the spring member.

[0033] The fixing members may be designed to break in response to a load greater than or equal to a predetermined value, and the pressure limit may be defined as the minimum internal pressure of the battery module at which the fixing members break.

[0034] When the internal pressure of the battery module exceeds the pressure limit and venting occurs as described above, the internal pressure of the battery module is further reduced by the venting, and the top plate is rejoined to the frame by the restoring force provided by the spring member, thereby sealing the battery module.

[0035] One side corner of the top plate and one side corner of the upper end of the side wall of the frame may be hinged to each other, so that the battery module may be open between the other side corner of the top plate and the other side corner of the upper end of the side wall of the frame.

[0036] The expansion member may be provided as part of the top plate.

[0037] The expansion member may be coupled to the top plate to cover and seal a hole that passes through the top plate in the vertical direction, or the expansion member may be formed integrally with the top plate.

[0038] The expansion member may be made of a heat-resistant and / or fire-resistant material, for example, a metal material.

[0039] The expansion member may expand outward as the internal pressure of the battery module increases, thereby expanding the internal space of the battery module.

[0040] There may be one or more expansion members.

[0041] The expansion member may be an elastic diaphragm that expands outward as the internal pressure of the battery module increases, or an inverted disk that yields and protrudes outward when the internal pressure of the battery module is equal to or greater than a yield pressure.

[0042] The expansion of the expansion member expands the internal space of the battery module, thereby delaying an increase in internal pressure of the battery module due to vent gas and thermal energy generated when the battery cell stack ignites.

[0043] The means for solving the above problems can also be applied to a battery pack including a battery module according to the present invention and a vehicle including the battery pack. Since the manufacturing methods of these battery packs and vehicles are well known, they will not be described in detail in this specification. [Effects of the Invention]

[0044] The present invention provides a battery module structure in which an expansion member is provided on the top plate so that the internal space can expand in the event of a fire, thereby maintaining a sealed state and preventing or delaying an increase in internal pressure, thereby preventing or delaying the release of flames and explosions.

[0045] In addition, the present invention provides a battery module structure that employs a structure in which the top plate is opened when internal pressure exceeding the pressure-resistance limit is generated, thereby enabling venting due to ignition to be induced upward.

[0046] Another advantage of the present invention is that the frame and the top plate are joined to each other by a spring member, thereby providing a battery module structure that can be resealed after venting occurs.

[0047] In addition, the present invention can have various other effects, which will be explained in each embodiment, or explanations of effects that can be easily inferred by ordinary engineers will be omitted. [Brief explanation of the drawings]

[0048] [Figure 1] FIG. 1 is a perspective view showing a general battery module. [Figure 2]FIG. 1 is an exploded perspective view showing a general battery module. [Figure 3] 1 is a schematic diagram showing how thermal energy and flames are transferred between battery modules. FIG. [Figure 4] 1 is a schematic diagram showing how thermal energy and flames are transferred between battery modules. FIG. [Figure 5] 1 is a perspective view showing a battery module according to a first embodiment of the present invention, in which an elastic diaphragm is provided on a top plate. [Figure 6] 1 is a side cross-sectional view showing a battery module according to Example 1 of the present invention, which has an elastic diaphragm on the top plate, before ignition. [Figure 7] 1 is a side cross-sectional view showing the battery module according to Example 1 of the present invention, which has an elastic diaphragm on the top plate, after ignition. FIG. [Figure 8] FIG. 10 is a perspective view showing a battery module according to a second embodiment of the present invention, in which an inverted plate is provided on the top plate. [Figure 9] FIG. 10 is a side cross-sectional view showing a battery module according to Example 2 of the present invention, which has a top plate provided with an inversion plate, before ignition. [Figure 10] FIG. 10 is a side cross-sectional view showing the state of a battery module according to Example 2 of the present invention, in which an inversion plate is provided on the top plate, after ignition. [Figure 11] FIG. 10 is a perspective view showing a battery module according to a third embodiment of the present invention, which includes a reversal plate and a spring member. [Figure 12] FIG. 10 is a side cross-sectional view showing a battery module according to Example 3 of the present invention, which includes a reversal plate and a spring member, before ignition. [Figure 13] FIG. 10 is a side cross-sectional view showing a state of a battery module according to Example 3 of the present invention, which includes a reversal plate and a spring member, after ignition. [Figure 14] FIG. 10 is a perspective view showing a battery module according to a fourth embodiment of the present invention, which includes a reversal plate, a spring member, and a spring shaft. [Figure 15] 1 is a side cross-sectional view of a battery module according to an embodiment of the present invention, including a reversal plate, a spring member, and a spring shaft, showing the state before ignition; [Figure 16] 1 is a side cross-sectional view of a battery module according to an embodiment of the present invention, including a reversal plate, a spring member, and a spring shaft, showing the state after ignition; [Figure 17] FIG. 10 is a perspective view showing a battery module according to a fifth embodiment of the present invention, which includes a reversal plate, a spring member, and a hinge. [Figure 18] 1 is a perspective view showing a battery pack including a battery module according to the present invention; [Figure 19] FIG. 19 is a perspective view showing an electric vehicle including the battery pack of FIG. 18. DETAILED DESCRIPTION OF THE INVENTION

[0049] The above-mentioned objects, features, and advantages will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the technical concept of the present invention. In describing the present invention, if a detailed description of known technologies relating to the present invention is deemed to obscure the gist of the present invention, the detailed description will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings are used to indicate the same or similar components.

[0050] Although terms such as "first" and "second" are used to describe various components, it is understood that these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a first component may also be a second component.

[0051] Unless otherwise specified in the entire specification, each element may be singular or plural.

[0052] Hereinafter, when an arbitrary structure is arranged "on top (or bottom)" of a component or "above (or below)" a component, it means that the arbitrary structure is not only arranged in contact with the upper surface (or lower surface) of the component, but also that other structures may be interposed between the component and the arbitrary structure arranged above (or below) the component.

[0053] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it should be understood that the components may be directly coupled or connected to each other, but that other components may be "intervening" between the components, or that each component may be "coupled," "coupled," or "connected" via other components.

[0054] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise. Terms such as "comprise" or "include" in this application should not be interpreted as including all of the multiple components or multiple steps described in the specification, but should be interpreted as meaning that some of the components or some of the steps may not be included, or that additional components or steps may be included.

[0055] Throughout the specification, unless otherwise specified, "A and / or B" means A, B or A and B, and "C to D" means C or more and D or less.

[0056] The present invention provides By providing an expansion member that can expand the internal space by expanding in response to an increase in internal pressure within a predetermined pressure limit, the increase in internal pressure is prevented or delayed, and the release of heat energy and flames is prevented or delayed; When the internal pressure exceeds the pressure limit, the top plate opens, inducing upward venting and preventing the transfer of heat energy and flames to other battery modules; By providing a spring member, a battery module structure is provided that can be further sealed after venting is completed, thereby preventing the risk of heat energy and flames transferring from other battery modules.

[0057] Hereinafter, in this specification, the explosion pressure of a battery module is defined as the minimum internal pressure at which the explosion of the battery module can occur.

[0058] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0059] [Example 1] 5 is a perspective view showing a battery module according to a first embodiment of the present invention, which has an elastic diaphragm on a top plate. Referring to this figure, the battery module 1 according to the present invention may include a battery cell stack, a frame 4 that houses the battery cell stack and is open at the top, a top plate 3 that covers the top of the frame 4, a spring member (not shown) that presses and fixes the top plate 3 downward so that the top plate 3 contacts the upper end of a side wall of the frame 4, and an expansion member 31 provided on a part of the top plate 3.

[0060] The frame 4 may be in a form that is open at the top, and in particular, may be in the form of a box that is open at the top.

[0061] The frame 4 may include a U-shaped U-frame 41 that is open at the front, rear, and top, and a pair of end plates 42 that are joined to the U-frame 41 and cover the front and rear of the U-frame 41, respectively.

[0062] The U-frame 41 may be made of various materials and manufactured by various methods. For example, the U-frame may be made of a single metal plate that is plastically deformed into a U-shape by pressing.

[0063] The end plates 42 and the U-frame 41 may be joined to each other in various ways, for example, the end plates 42 and the U-frame 41 may be joined to each other by welding or by friction fitting.

[0064] The top plate 3 can cover the open upper part of the frame 4 .

[0065] The battery module 1 may be sealed by joining the frame 4 and the top plate in a fully assembled state, and may be sealed to prevent gas or flame from passing between the inside and outside unless there are special circumstances.

[0066] The expansion member 31 may be provided as part of the top plate 3 .

[0067] The expansion member 31 may be attached to the top plate 3 so as to cover and seal a hole that passes through the top plate 3 from top to bottom. Alternatively, the expansion member 31 may be formed integrally with the top plate 3.

[0068] The expansion member 31 may be made of a heat-resistant and / or fire-resistant material, for example, a metal material.

[0069] The expansion member 31 may expand outward in response to an increase in the internal pressure of the battery module, thereby expanding the internal space of the battery module 1.

[0070] The expansion member 31 may be provided in one or more pieces.

[0071] The expansion member 31 may be an elastic diaphragm that increases in size and expands outward as the internal pressure of the battery module 1 increases.

[0072] 6 and 7 are side cross-sectional views showing the battery module according to Example 1 of the present invention, which includes an elastic diaphragm on the top plate, before and after ignition, respectively. Referring to these drawings, in the battery module 1 including the elastic diaphragm 31E, when the battery cell stack ignites, a large amount of vent gas is generated, causing a rapid rise in internal temperature and an increase in internal pressure of the battery module 1. In this case, the elastic diaphragm 31E expands due to the increase in internal pressure, thereby expanding the internal space of the battery module 1. Because the amount of gas pressure is inversely proportional to its volume, the expansion of the internal space of the battery module 1 as described above can prevent or delay the increase in internal pressure of the battery module 1 due to the vent gas and thermal energy.

[0073] By preventing an increase in the internal pressure of the battery module 1, the internal pressure of the battery module 1 may not reach its explosion pressure. Alternatively, by delaying an increase in the internal pressure of the battery module 1, the time until the internal pressure of the battery module 1 reaches the explosion pressure may be delayed.

[0074] On the other hand, when the elastic diaphragm 31E is provided on the top plate 3, the direction of the expansion is also upward, and even if the elastic diaphragm 31E ruptures, the flame, heat energy, and vent gas caused by the ignition can be discharged upward.

[0075] When the ignition is stopped and the internal temperature and pressure of the battery module 1 are further reduced, the elastic diaphragm 31E can further contract and return to its original state.

[0076] [Example 2] 8 is a perspective view showing a battery module according to a second embodiment of the present invention, which includes a top plate having a reversal plate. Referring to this figure, the expansion member 31 may be a reversal disk 31R that is normally recessed inside the battery module 1 and, when the internal pressure of the battery module 1 exceeds a yield pressure, yields and reverses, protruding outward.

[0077] The reversing disc 31R may be a resilient cup-shaped member. For example, the reversing disc 31R may be a cup-shaped metal member including a peripheral portion, a recessed portion recessed to one side of the peripheral portion, and a protruding portion protruding to one side of the peripheral portion on the opposite side of the recessed portion. When a pressure equal to or greater than the yield pressure is applied to the protruding portion toward the other side, the shape of the reversing disc 31R is reversed, and the recessed portion becomes a protruding portion protruding to the other side of the peripheral portion, and the protruding portion becomes a recessed portion recessed to the other side of the peripheral portion. In this case, the reversing disc 31R may further include, in addition to the peripheral portion, a portion whose shape does not reverse even when the recessed portion and the protruding portion are reversed.

[0078] The reversal disc 31R may be a reversal-activated rupture disc that reverses its shape when the internal pressure of the mounting portion increases to or exceeds a design reversal pressure and ruptures when the internal pressure of the mounting portion increases to or exceeds a design burst pressure. Preferably, the reversal disc 31R may be a reversal-activated rupture disc whose design reversal pressure is smaller than the explosion pressure of the battery module 1 and whose design burst pressure is larger than the explosion pressure. In this case, the design reversal pressure is the same as the yield pressure.

[0079] 9 and 10 are side cross-sectional views showing the battery module according to Example 2 of the present invention, which includes an inversion plate on the top plate, before and after ignition, respectively. Referring to these drawings, in the battery module 1 including the inversion disc 31R, when the battery cell stack ignites, a large amount of vent gas is generated, causing a rapid rise in internal temperature and an increase in internal pressure of the battery module 1. If the internal pressure of the battery module 1 exceeds the yield pressure of the inversion disc 31R, the inversion disc 31R inverts its shape and protrudes outward, expanding and thereby expanding the internal space of the battery module 1. Because the amount of gas pressure is inversely proportional to its volume, the expansion of the internal space of the battery module 1 as described above can prevent or delay the increase in internal pressure of the battery module 1 due to the vent gas and thermal energy.

[0080] By preventing an increase in the internal pressure of the battery module 1, the internal pressure of the battery module 1 may not reach its explosion pressure. Alternatively, by delaying an increase in the internal pressure of the battery module 1, the time until the internal pressure of the battery module 1 reaches the explosion pressure may be delayed.

[0081] On the other hand, if the inversion disc 31R is installed on the top plate 3, the direction of the expansion will also be upward, and even if the inversion disc 31R bursts, the flame, heat energy, and vent gas caused by the ignition can be discharged upward.

[0082] [Example 3] 11 is a perspective view showing a battery module including a reversal plate and a spring member according to a third embodiment of the present invention. Referring to this figure, the battery module 1 according to the third embodiment of the present invention may include a spring member 32 that presses the top plate 3 downward so that the top plate 3 contacts the upper end of the side wall of the frame 4, thereby fixing the top plate 3 to cover the open upper part of the frame 4.

[0083] The spring member 32 may be provided in one or more pieces.

[0084] The spring member 32 may be a coil spring made of a metal material, but is not limited to this.

[0085] The lower end of the spring member 32 may be embedded in the upper end of the side wall of the frame 4. The embedded installation may be performed by insert injection, and may be performed by assembling a separate member for fixing. In this case, the upper end of the spring member 32 may be fixed to the top plate 3.

[0086] If the side wall of the frame 4 itself is sufficiently thick, the spring member 32 can be directly embedded in the upper end of the side wall, and if the side wall of the frame 4 is not thick enough, the spring member 32 can be embedded in a spring mounting portion 411 that protrudes further inward from the upper end of the side wall.

[0087] As described above, each end of the spring member 32 is fixed to the upper end of the side wall of the frame 4 and the top plate 3, so that the spring member 32 may have a restoring force that pulls the top plate 3 when the top plate 3 moves away from the upper end of the side wall of the frame 4, thereby restoring the top plate 3 to the upper end of the side wall of the frame 4.

[0088] A compressible packing is further installed on the upper end of the side wall of the frame 4, so that the pressure applied by the spring member 32 can more easily seal the gap between the top plate 3 and the frame 4.

[0089] 12 and 13 are side cross-sectional views showing the battery module according to Example 3 of the present invention, which includes an inversion plate and a spring member, before and after ignition, respectively. Referring to these drawings, the battery module 1 may have a pressure limit defined by the maximum internal pressure of the battery module 1 at which the bond between the top plate 3 and the frame 4 can be maintained and the battery module 1 can remain sealed.

[0090] The spring member 32 may be a pre-stressed spring that is pre-tensioned or pre-compressed so that it has a predetermined restoring force even when the top plate 3 and the frame 4 are in complete contact with each other. As a result, the pressure limit can be defined as the minimum internal pressure of the battery module 1 at which further tension or compression occurs in the spring member 32.

[0091] Alternatively, the top plate 3 and the frame 4 may be connected and joined to each other by an additional fixing member in addition to the spring member 32. In this case, the fixing member may be designed to break under a predetermined load or more, and the pressure resistance limit may be defined as the minimum internal pressure of the battery module 1 at which the fixing member breaks.

[0092] The pressure-resistant limit may be set lower than the explosion pressure. Thus, when the battery module 1 ignites, the internal pressure of the battery module 1 reaches the pressure-resistant limit before reaching the explosion pressure, causing the top plate 3 to be disengaged from the frame 4, thereby opening the battery module 1 upward. As a result, the flame, heat energy, and vent gas generated from the battery cell stack are vented upward, reducing the internal pressure of the battery module 1.

[0093] In the battery module 1 according to this embodiment, if the internal pressure of the battery module 1 increases due to thermal energy, flames, and vent gases generated by the ignition of the battery cell stack, and if the internal pressure is equal to or greater than the yield pressure of the inversion disc 31R, the shape of the inversion disc 31R is inverted, expanding the internal space of the battery module 1, thereby reducing or delaying the increase in the internal pressure; if the internal pressure continues to increase despite the expansion of the inversion disc 31R and exceeds the withstand pressure limit, the connection between the top plate 3 and the frame 4 is released, opening the top of the battery module 1 and causing venting; if the internal pressure further decreases to below the withstand pressure limit due to the venting, the top plate 3 and the frame 4 are reconnected by the spring member 32, and the battery module 1 can be resealed.

[0094] [Example 4] 14 is a perspective view showing a battery module according to a fourth embodiment of the present invention, which includes a reversal plate, a spring member, and a spring shaft. Referring to this figure, a spring shaft 32A can be embedded in the upper end of the side wall of the frame 4 instead of the spring member 32. In this case, the embedded installation can be performed by insert injection, and a separate member can be provided for fixing and assembled.

[0095] If the side wall of the frame 4 itself is sufficiently thick, the spring shaft 32A can be directly embedded in the upper end of the side wall, and if the side wall of the frame 4 is not thick enough, the spring shaft 32A can be embedded in a spring mounting portion 411 that protrudes further inward from the upper end of the side wall.

[0096] The spring shaft 32A may be formed so as to pass through the top plate 3 in the vertical direction.

[0097] The upper end of the spring shaft 32A may be provided with a fixed end 322 having a radius larger than that of the spring member 32, to which the spring member 32 can be fixed.

[0098] The spring member 32 may be installed between the top plate 3 and the fixed end 322 so as to penetrate the spring shaft 32A. That is, the spring member 32 may be installed such that its upper end is fixed in contact with the fixed end 322 and its lower end is fixed in contact with the top plate 3, and the spring member 32 may be installed such that it is interposed between the fixed end 322 and the top plate 3 from above and below.

[0099] As described above, the spring member 32 may be provided with the spring shaft 32A connected to the upper end of the side wall of the frame 4 and penetrating the top plate 3, and a spring member 32 installed between the fixed end located at the upper end of the spring shaft 32A and the top plate 3, penetrating the spring shaft 32A, so that the top plate 3 is compressed when it moves away from the upper end of the side wall of the frame 4, thereby providing a restoring force that tends to restore the top plate 3 to the upper end of the side wall of the frame 4.

[0100] A compressible packing is further installed on the upper end of the side wall of the frame 4, so that the space between the top plate 3 and the frame 4 can be more easily sealed by the pressure applied by the spring member 32.

[0101] 15 and 16 are side cross-sectional views showing the battery module 1 according to an embodiment of the present invention, including a reversal plate, a spring member, and a spring shaft, before and after ignition. Referring to these drawings, the spring member 32 may be a pre-stressed spring that is pre-tensioned or pre-compressed so as to have a predetermined restoring force even when the top plate 3 and the frame 4 are in complete contact with each other. Therefore, the pressure limit can be defined by the minimum internal pressure of the battery module 1 at which the spring member 32 is further tensioned or compressed.

[0102] Alternatively, the top plate 3 and the frame 4 may be connected and joined to each other by an additional fixing member in addition to the spring member 32. In this case, the fixing member may be designed to break in response to a load equal to or greater than a predetermined value, and the pressure resistance limit may be defined as the minimum internal pressure of the battery module 1 at which the fixing member breaks.

[0103] The pressure-withstanding limit may be set lower than the explosion pressure. Thus, when the battery module 1 ignites, the internal pressure of the battery module 1 reaches the pressure-withstanding limit before reaching the explosion pressure. As a result, the top plate 3 is released from the frame 4, and the battery module 1 is opened upward. As a result, the flame, heat energy, and vent gas generated from the battery cell stack are vented upward, and the internal pressure of the battery module 1 may decrease.

[0104] In the battery module 1 according to this embodiment, if the internal pressure of the battery module 1 increases due to thermal energy, flames, and vent gases generated by the ignition of the battery cell stack, and if the internal pressure exceeds the yield pressure of the inversion disc 31R, the shape of the inversion disc 31R will invert, expanding the internal space of the battery module 1, thereby reducing the internal pressure or delaying the increase in the internal pressure; if the internal pressure continues to increase despite the expansion of the inversion disc 31R and exceeds the withstand pressure limit, the connection between the top plate 3 and the frame 4 will be released, opening the top of the battery module 1 and causing venting; if the internal pressure further decreases below the withstand pressure limit due to the venting, the top plate 3 and the frame 4 will be reconnected by the spring member 32, and the battery module 1 will be resealed.

[0105] [Example 5] 17 is a perspective view showing a battery module according to Example 5 of the present invention, which includes a reversible plate, a spring member, and a hinge. Referring to this figure, one side corner of the top plate 3 and one side corner of the upper end of the side wall of the frame 4 can be connected to each other by a hinge 412. Therefore, the top plate 3 can rotate around the hinge 412 between the other side corner of the top plate 3 and the other side corner of the upper end of the side wall of the frame 4 to open and close. This improves the stability of the opening and closing operation of the top plate 3, and allows the thermal energy, flame, and vent gas generated when the battery module 1 ignites to be vented in a desired horizontal direction above the battery module 1.

[0106] 18 and 19 are perspective views showing a battery pack including a battery module according to the present invention and an electric vehicle including the battery pack, respectively. Referring to these figures, a plurality of battery modules 1 according to the present invention can be connected in series or parallel to form a battery pack (P) with increased voltage or charge / discharge capacity, and the battery pack (P) can be included in a vehicle (V) and used as a power source. Methods for manufacturing the battery pack (P) and the vehicle (V) are well known to those skilled in the art, and therefore will not be described in detail herein.

[0107] It should be understood that the above-described embodiments are illustrative in all respects and are not limiting, and the scope of the present invention is defined by the following claims rather than the above detailed description. All modifications and variations within the meaning and scope of the following claims, as well as equivalent concepts, should be construed as being included within the scope of the present invention.

[0108] Although the present invention has been described above with reference to illustrative drawings, the present invention is not limited to the embodiments and drawings disclosed in this specification, and it is obvious that various modifications can be made by those skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration of the present invention are not explicitly described and explained while describing the embodiments of the present invention, it is natural that the effects that can be predicted by the configuration should also be recognized. [Explanation of symbols]

[0109] 1 Battery Module 2 Battery cell stack 21 Battery Cells 3 Top Plate 31 Expansion member 31E Elastic diaphragm 31R Reverse Disc 32 Spring member 32A spring shaft 322 Spring fixed end 4 frames 41 U-frame 411 Spring installation section 412 Hinge 42 End plate Terminal 5 51 Exposed terminal P Battery pack V Automobile

Claims

1. In a battery module including a battery cell stack, an upper open frame; a top plate joined to the frame and covering the open upper portion of the frame; a spring member that presses the top plate downward to fix it in place so that the top plate contacts an upper end of a side wall of the frame; an expansion member provided on a portion of the top plate; the expansion member expands outward as the internal pressure of the battery module increases, thereby expanding the internal space of the battery module. Battery module.

2. the expansion member is an elastic diaphragm that expands outward as the internal pressure of the battery module increases; The battery module according to claim 1 .

3. an explosion pressure defined as the minimum internal pressure at which an explosion of the battery module can occur; a pressure limit defined by the maximum internal pressure of the battery module at which the bond between the top plate and the frame is maintained; The pressure limit is less than the explosion pressure. The battery module according to claim 2 .

4. The spring member is a pre-stressed spring that is pre-tensioned or pre-compressed so as to have a predetermined restoring force, Thereby, the pressure limit is defined as the minimum internal pressure at which further tension or compression occurs in the spring member. The battery module according to claim 3 .

5. The top plate and the frame are connected and joined to each other by a further fixing member in addition to the spring member, The fixing member is designed to break in response to a load equal to or greater than a predetermined value, Thereby, the withstand pressure limit is defined as the minimum internal pressure of the battery module at which the fixing member is broken. The battery module according to claim 3 .

6. the expansion member is an inverted disk that yields and protrudes outward when the internal pressure of the battery module is equal to or greater than a yield pressure; The battery module according to any one of claims 1 to 5.

7. an explosion pressure defined as the minimum internal pressure at which an explosion of the battery module can occur; a pressure limit defined by the maximum internal pressure of the battery module at which the bond between the top plate and the frame is maintained; The pressure limit is greater than the yield pressure and less than the explosion pressure. The battery module according to claim 2 .

8. The spring member is a prestressed spring that is pre-tensioned or pre-compressed so as to have a predetermined restoring force, Thereby, the pressure limit is defined as the minimum internal pressure at which further tension or compression occurs in the spring member. The battery module according to claim 7 .

9. The top plate and the frame are connected and joined to each other by a further fixing member in addition to the spring member, The fixing member is designed to break in response to a load equal to or greater than a predetermined value, Thereby, the fixing member is defined by the minimum internal pressure of the battery module at which the fixing member is broken. The battery module according to claim 7 .

10. The spring member is embedded in the upper end of the side wall of the frame, and fixes the top plate by applying tension and pressure to the upper end of the side wall of the frame. The battery module according to any one of claims 1 to 5.

11. a spring shaft extending upward from a side wall of the frame through the top plate; a spring fixing end to which the spring member is fixed is provided at an upper end of the spring shaft; The spring member is installed between the spring fixed end and the top plate, and fixes the top plate by compressing and pressing the top plate toward the upper end of the side wall of the frame. The battery module according to any one of claims 1 to 5.

12. One side corner of the top plate and one side corner of the upper end of the side wall of the frame are connected to each other by a hinge, Thus, the battery module can be opened between the other side corner of the top plate and the other side corner of the upper end of the side wall of the frame. The battery module according to claim 10.

13. One side corner of the top plate and one side corner of the upper end of the side wall of the frame are connected to each other by a hinge, Thus, the battery module can be opened between the other side corner of the top plate and the other side corner of the upper end of the side wall of the frame. The battery module according to claim 11 .

14. A battery module comprising the battery module according to any one of claims 1 to 5. Battery pack.

15. A battery pack comprising the battery pack of claim 14. car.

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