Battery module and battery pack with retarded heat propagation

Abstract

The present invention provides a battery module structure including a battery cell stack, a bus bar frame connected to the front of the battery cell stack and having terminals provided thereon, a module frame that is open at the front and houses the battery cell stack, an end plate that covers the front of the module frame and is provided with terminal exposure holes through which the terminals are exposed to the outside, and a thermal expansion member that is fastened together with the terminals, wherein the thermal expansion member expands when heated.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0182336 dated December 22, 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 containing battery cells and a battery pack containing a plurality of such battery modules, and to a battery module and battery pack structure that retards heat transfer between battery modules. [Background technology]

[0003] Secondary batteries, which are easily applicable to a wide range of products and have electrical properties such as high energy density, are commonly 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 because they not only have the primary advantage of dramatically reducing the use of fossil fuels, but also because they are environmentally friendly and improve energy efficiency by not producing any by-products from energy use.

[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 to manufacture medium- to large-sized battery modules with small size and weight if possible, prismatic batteries and pouch-shaped batteries, which can be stacked with high density and have low weight relative to capacity, are mainly used as battery cells for medium- to large-sized battery modules.

[0006] 1 and 2 are exploded and perspective views, respectively, showing the structure of a battery module. Referring to these drawings, the battery module is formed by housing a battery cell stack 1, in which multiple pouch-shaped battery cells 11 are stacked, in a module frame 2 that is open at the front.

[0007] A bus bar frame 12 is connected to the front of the battery cell stack 1. The bus bar frame 12 is provided with a module bus bar 122 to which electrode leads 111 protruding from the battery cells 11 are welded. The module bus bar 122 may be connected to a pair of terminals 123 each having a different polarity, and then connected to the outside.

[0008] The front of the module frame 2 is covered by an end plate 3 including a first plate 31 made of synthetic resin and a second plate 32 made of metal. The second plate 32 is disposed further forward than the first plate 31. The first plate 31 and the second plate 32 are provided with a first terminal exposure opening 311 and a second terminal exposure opening 321, respectively, which expose the terminals 123 to the outside. At this time, a terminal insulating portion 312 provided on the first plate 31 is exposed through the second terminal exposure opening 321 to insulate the terminals 123 from the second plate 32.

[0009] Fig. 3 shows a fastening structure between a terminal of a battery module and a pack bus bar, and Figs. 4 and 5 are a partial enlarged view and a cross-sectional view, respectively, showing the pack bus bar fastened to the terminal. Referring to these drawings, a pack bus bar 400 is fastened onto the terminal 123. The terminal 123 and the pack bus bar 400 are provided with first fastening holes 123H and second fastening holes 400H that penetrate vertically therethrough, respectively, and fastening members 410 pass through the first fastening holes 123H and the second fastening holes 400H and are fixed to fixing portions 313 provided on the end plate 3, thereby fastening the terminal 123 and the pack bus bar 400 to each other. A plurality of the battery modules are arranged facing each other in the front and rear and connected in series or parallel by the pack bus bar 400 to form a battery pack.

[0010] Meanwhile, the battery cell 11 may ignite due to a short circuit, impact, temperature rise, etc. If the battery cell 11 ignites, high-temperature gas is emitted from inside the battery cell 11. At this time, the first plate 31 may be heated and melted by the gas. As a result, the gas may be discharged forward through gaps between the first fastening holes 123H and the second fastening holes 400H and the fastening members 410, and through cavities created by the melting of the first plate 31 due to an explosive increase in internal pressure of the module frame 2.

[0011] In this case, other battery modules located in front of the battery module where the fire occurred in the battery pack may be heated by the gas. Just as the high-temperature gas generated in the battery module is likely to be discharged to the outside through the front, the high-temperature gas outside the battery module is likely to flow into the inside through the front of the battery module. The heat transfer between these battery modules may cause thermal runaway, resulting in a chain reaction of fires among the battery modules. Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention was made in light of the above-described background of the prior art, and aims to provide a battery module structure that delays or prevents gas from escaping in a specific direction in the event of a fire. Specifically, the present invention aims to provide a battery module that delays or prevents gas from escaping through the front of the battery module where the terminal exposure opening is provided.

[0013] Another object of the present invention is to provide a battery module structure that delays or prevents the inflow of gases discharged from adjacent battery modules.

[0014] A further technical object of the present invention is to provide a battery module structure that guides gas to be discharged in a direction other than the forward direction in the event of a fire.

[0015] A further technical object of the present invention is to provide a structure of a battery module and a battery pack in which heat transfer between battery modules is delayed or prevented.

[0016] The technical object of the present invention is not limited to the above-mentioned objects, and other unmentioned objects and advantages of the present invention can be understood from the following description and can be more clearly understood from the examples of the present invention. Furthermore, it can be easily understood that the objects and advantages of the present invention can be achieved by the means and combinations thereof set forth in the claims. [Means for solving the problem]

[0017] In order to solve the above problems, the present invention provides a battery module structure including: a battery cell stack; a bus bar frame connected to the front of the battery cell stack and having terminals provided thereon; a module frame that is open at the front and houses the battery cell stack; an end plate that covers the front of the module frame and is provided with terminal exposure holes through which the terminals are exposed to the outside; and a thermal expansion member that is fastened together with the terminals, wherein the thermal expansion member expands when heated.

[0018] The means for solving these problems can be applied to battery modules that include terminals exposed to the outside, and therefore have the risk of high-temperature gas being emitted in the direction of the exposed terminals when a battery cell ignites, particularly battery modules in which the exposed portions of the terminals contain synthetic resin material and are therefore likely to melt due to the gas.

[0019] The thermal expansion member may be fastened directly to the terminal or through a pack bus bar. The pack bus bar may be electrically connected to the terminal. The thermal expansion member may be fastened above the terminal.

[0020] The terminal, the pack bus bar, the thermal expansion member, and the thermal expansion member may each include a first fastening hole, a second fastening hole, and a third fastening hole that penetrates them vertically, and may include fastening members that penetrate the first fastening hole, the second fastening hole, and the third fastening hole simultaneously to fasten the terminal, the pack bus bar, the thermal expansion member, and the thermal expansion member to each other.

[0021] In this case, the fastening member may include a head portion that interferes with the thermal expansion member, and a lower end of the fastening member may be fixed by engaging with a fixing portion provided on the end plate.

[0022] The end plate may include a first plate made of a synthetic resin material and having a first terminal exposure opening, and a second plate made of a metal material and having a second terminal exposure opening, which is located longitudinally outward of the first plate.

[0023] The first plate may include a terminal insulating portion exposed to the outside through the second terminal exposure hole for insulation between the second plate and the terminal, and the thermal expansion member may include a first portion in contact with the pack bus bar and a second portion in contact with the terminal insulating portion.

[0024] When the battery module catches fire, the thermal expansion member expands in volume to fill empty spaces such as gaps between the fastening holes and the fastening members, gaps created by melting the first plate, and gaps between the terminals and the second plate, thereby delaying or preventing high-temperature gas from being discharged to the front of the battery module.

[0025] The battery module may include a pressure member that is fastened together with the thermal expansion member and the terminal on the thermal expansion member.

[0026] The terminal, the pack bus bar, the thermal expansion member, and the pressure member may each include a first fastening hole, a second fastening hole, a third fastening hole, and a fourth fastening hole that penetrates them vertically, and may include a fastening member that penetrates the first fastening hole, the second fastening hole, the third fastening hole, and the fourth fastening hole simultaneously to fasten the terminal, the pack bus bar, the thermal expansion member, and the pressure member to one another.

[0027] In this case, the fastening member may include a head portion that interferes with the pressure member, and a lower end of the fastening member may be engaged with and fixed to a fixing portion provided on the end plate.

[0028] The pressure member may be made of a flame-retardant material, i.e., a material that can maintain its shape even when heated to a high temperature and provide a counter force against the expansion of the thermal expansion member.

[0029] The pressure member may be formed in a shape corresponding to the thermal expansion member, cover a portion of the surface of the thermal expansion member, and apply pressure inward, which allows the thermal expansion member to expand further inward and more densely fill gaps in front of the battery module than when the pressure member is not provided.

[0030] The battery module may include a flame-retardant cover that covers the surface of the module frame, and a pressure fixing portion that protrudes and extends from the front end of the flame-retardant cover and is fastened to the thermal expansion member and the terminal on the thermal expansion member.

[0031] The flame-retardant cover may be made of a flame-retardant material. The flame-retardant cover may be made of a rigid or flexible material. The flame-retardant cover may cover a top surface of the module frame. The flame-retardant cover may also cover a side surface of the module frame.

[0032] The upper surface of the flame-retardant cover may be provided with a vent hole for discharging gas generated inside the module frame. If the flame-retardant cover is made of a flexible material, the vent hole may be provided in the form of a slit. In this case, vent holes may be provided not only in the flame-retardant cover but also in the upper surface of the module frame. By providing the vent holes in the flame-retardant cover and the upper surface of the module frame, gas that is not discharged to the front side of the battery module can be discharged above the battery module. In this case, the vent hole provided in the flame-retardant cover may be smaller than the vent hole provided in the module frame.

[0033] The flame-retardant cover may include a pressure fixing portion that protrudes from a front end thereof and is fastened to the terminal, the pack bus bar, and the thermal expansion member. The pressure fixing portion may be made of a flame-retardant material and may be a rigid or flexible body. Alternatively, the pressure fixing portion may have a reinforced structure in which a rigid body is bonded to a flexible body.

[0034] The terminal, the pack bus bar, the thermal expansion member, and the pressure fixing portion may each include a first fastening hole, a second fastening hole, a third fastening hole, and a fifth fastening hole that penetrates them vertically, and may include a fastening member that penetrates the first fastening hole, the second fastening hole, the third fastening hole, and the fifth fastening hole simultaneously to fasten the terminal, the pack bus bar, the thermal expansion member, and the pressure fixing portion to one another.

[0035] In this case, the fastening member may include a head portion that interferes with the pressure fixing portion, and a lower end of the fastening member may be engaged with and fixed to a fixing portion provided on the end plate.

[0036] The pressure fixing portion is formed in a shape corresponding to the thermal expansion member, and can cover a portion of the surface of the thermal expansion member and apply pressure inward, allowing the thermal expansion member to expand further inward than if the pressure fixing portion were not provided, and more densely filling gaps occurring in front of the battery module.

[0037] The battery module may include neither the pressure member nor the pressure fixing part, or may include both. Alternatively, the pressure fixing part may be integral with the pressure member or replace the pressure member. When both the pressure member and the pressure fixing part are provided, the pressure fixing part may be disposed above or below the pressure member.

[0038] The thermal expansion member may contain one or more materials selected from the group consisting of thermal expansion resins including soft urethane, lightweight urethane, and phosphorus-based flame retardants. In this case, the thermal expansion member may be formed of a foam material. However, the thermal expansion member is not limited to materials containing any of the above-listed materials, as long as it is made of a material whose volume expands when heated.

[0039] The present invention also provides a battery pack incorporating the battery module and a vehicle structure incorporating the battery pack.

[0040] A plurality of the battery modules may be housed in a single pack frame to form a high-voltage and / or high-capacity battery pack. Within the battery pack, the battery modules may be arranged facing each other in the front-rear direction. In this case, the plurality of pack bus bars may electrically connect the plurality of terminals provided on the plurality of battery modules in series or parallel to each other.

[0041] The battery pack can be installed as an energy source in automobiles, including electric and hybrid automobiles. [Effects of the Invention]

[0042] The present invention can provide a battery module structure in which a thermal expansion member fills the space generated in front of the battery module where the terminals are installed, thereby delaying or preventing the discharge and inflow of gas to the front.

[0043] The present invention can provide a battery module structure in which, in the event of a fire, the thermal expansion member expands, preventing gas from being emitted through empty spaces that are generated when the first plate melts due to high heat.

[0044] The present invention can provide a battery module structure in which, in the event of a fire, the thermal expansion member expands, preventing gas from escaping through the gap between the terminal exposure opening and the terminal.

[0045] The present invention can provide a battery module structure in which, in the event of a fire, the thermal expansion member expands, preventing gas from escaping through gaps between the fastening members and the fastening holes provided in the terminals and pack bus bars.

[0046] In the battery module according to an embodiment of the present invention, high-temperature gas generated upon ignition can be directed to be discharged upward rather than forward.

[0047] In the battery module according to an embodiment of the present invention, the pressure fixing portion fixes the flame-retardant cover, so that the flame-retardant cover may not come off from the module frame even under high pressure.

[0048] The present invention can provide a battery module and battery pack structure that delays or prevents heat transfer between battery modules.

[0049] In addition to the above, the present invention can achieve 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]

[0050] [Figure 1] FIG. 2 is an exploded perspective view showing the structure of a battery module. [Figure 2] FIG. 2 is a perspective view showing the structure of a battery module. [Figure 3] 10A and 10B are diagrams showing a fastening structure between a terminal of a battery module and a pack bus bar. [Figure 4] 4 is a partial enlarged view of the battery module of FIG. 3 with a second plate removed. FIG. [Figure 5] 4 is a cross-sectional view of the battery module of FIG. 3 with a second plate removed. [Figure 6] 1 is an exploded perspective view showing the structure of a battery module according to a first embodiment of the present invention. [Figure 7] 1 is a perspective view showing the structure of a battery module according to a first embodiment of the present invention. [Figure 8] 2 is a partially enlarged view of the battery module according to the first embodiment of the present invention with a second plate removed. FIG. [Figure 9] 1 is a cross-sectional view of a battery module according to a first embodiment of the present invention with a second plate removed. [Figure 10] 1 is a diagram showing the expansion action of the thermal expansion member according to Example 1 of the present invention, where the arrow indicates the expansion direction of the thermal expansion member. [Figure 11] FIG. 10 is an exploded perspective view showing the structure of a battery module according to a second embodiment of the present invention. [Figure 12] FIG. 10 is a perspective view showing the structure of a battery module according to a second embodiment of the present invention. [Figure 13] FIG. 10 is a partially enlarged view of a battery module according to a second embodiment of the present invention with a second plate removed. [Figure 14] FIG. 10 is a cross-sectional view of a battery module according to a second embodiment of the present invention with a second plate removed. [Figure 15] 10 is a diagram showing the expansion action of a thermal expansion member according to Example 2 of the present invention, where the arrow indicates the expansion direction of the thermal expansion member. [Figure 16] FIG. 10 is an exploded perspective view showing the structure of a battery module according to a third embodiment of the present invention. [Figure 17] FIG. 10 is a perspective view showing the structure of a battery module according to a third embodiment of the present invention. [Figure 18] 1 is a diagram showing a battery pack incorporating a battery module according to the present invention; [Figure 19] FIG. 20 is a diagram showing a car incorporating the battery pack of FIG. 18. DETAILED DESCRIPTION OF THE INVENTION

[0051] 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.

[0052] Although terms such as "first" and "second" are used to indicate 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.

[0053] Throughout the specification, unless otherwise specified, each element may be singular or plural.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] In the entire specification, "A and / or B" means A, B or A and B unless otherwise specified, and "C to D" means C or more and D or less unless otherwise specified.

[0058] 1 and 2 are exploded and perspective views, respectively, showing the structure of a battery module. Referring to these drawings, the battery module may include a battery cell stack 1, a module frame 2 that is open at the front and houses the battery cell stack 1, and an end plate 3 that covers the front of the module frame 2.

[0059] The battery cell stack 1 may be formed by stacking a plurality of pouch-shaped battery cells 11. In this case, the battery cells 11 may include electrode leads 111 protruding to the outside. However, regardless of the name, the battery cell stack 1 may also be an assembly of one or more cells that constitute a battery, regardless of a specific structure or shape.

[0060] The battery cell stack 1 according to Examples 1 to 3 of the present invention may be formed by stacking a plurality of the battery cells 11. In this case, the battery cell 11 may include the electrode lead 111 protruding forward from its front end.

[0061] A bus bar frame 12 may be connected to the front of the battery cell stack 1. The bus bar frame 12 may include slits 121 through which the electrode leads 111 pass and a module bus bar 122 to which the electrode leads 111 are connected. The module bus bar 122 may connect the electrode leads 111 to each other in series or parallel and may be connected to a pair of terminals 123 having mutually opposite polarities. The bus bar frame 12 does not necessarily have to have the above structure, and may have any structure as long as it is connected to the electrode leads 111 and has terminals 123 that can connect the battery cell stack 1 to the outside.

[0062] The bus bar frame 12 according to the first to third embodiments of the present invention may include a plurality of the slits 121 through which the electrode leads 111 pass, and a plurality of the module bus bars 122 to which the electrode leads 111 are welded. In this case, the module bus bars 122 may be connected to a pair of the terminals 123 having different polarities, and the terminals 123 may be formed in a shape bent forward.

[0063] The module frame 2 may be formed in a shape that is open at the front. For example, the module frame 2 may be formed in a box shape that is open at the front. The module frame 2 may be made of a metal material. The module frame 2 may be formed by joining or assembling a plurality of members together.

[0064] The module frame 2 according to the first to third embodiments of the present invention may be made of a metal material and may include a U-shaped U-frame that is open at the front, rear, and top, and a top plate that covers the top of the U-frame. In this case, the U-frame and the top plate may be joined to each other by welding.

[0065] The end plate 3 may include a first plate 31 and a second plate 32 disposed forward of the first plate 31. In this case, the first plate 31 may be made of a synthetic resin material, and the second plate 32 may be made of a metal material. The first plate 31 and the second plate 32 may be provided with a first terminal exposure hole 311 and a second terminal exposure hole 321, respectively, that expose the terminal 123 to the outside.

[0066] The first plate 31 may include, as a part thereof, a terminal insulating portion 312 exposed to the outside through the terminal 123. The terminal insulating portion 312 is provided between the terminal 123 and the first plate 31 to electrically insulate them from each other. The terminal insulating portion 312 may include a portion that extends perpendicularly to the inner side of the terminal 123 in the length direction and / or width direction.

[0067] The end plate 3 according to Examples 1 to 3 of the present invention may include the first plate 31 made of a synthetic resin material and the second plate 32 made of a metal material, and the first plate 31 and the second plate 32 may include the first terminal exposure opening 311 and the second terminal exposure opening 321, respectively, which expose the terminal 123 to the outside, and the first plate 31 may include the terminal insulating portion 312, which is exposed to the outside through the second terminal exposure opening 321 and includes a portion formed vertically inside the lengthwise and widthwise directions of the terminal 123.

[0068] The present invention provides a battery module structure including a thermal expansion member fastened together with the terminal in the battery module as described above, the thermal expansion member being made of a material that expands when heated, thereby preventing high-temperature gas from being discharged to the side where the terminal is provided when the battery cell ignites.

[0069] The means for solving these problems can be applied to battery modules that include terminals exposed to the outside, and therefore have the risk of high-temperature gas being emitted in the direction of the exposed terminals when a battery cell ignites, particularly battery modules in which the exposed portions of the terminals contain synthetic resin material and are therefore likely to melt due to the gas.

[0070] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0071] [Example 1] 6 and 7 are an exploded perspective view and a perspective view, respectively, showing the structure of a battery module according to a first embodiment of the present invention, and FIGS. 8 and 9 are a partial enlarged view and a cross-sectional view, respectively, showing a state in which a second plate is removed from the battery module according to the first embodiment of the present invention. Referring to these drawings, a pack bus bar 400 and a thermal expansion member 420 may be fastened to the terminal 123.

[0072] The pack bus bar 400 may be fastened to the terminal 123 so as to be in direct contact with the terminal 123 and electrically connected to the terminal 123 .

[0073] The thermal expansion member 420 may be fastened to the terminal 123 on the terminal 123. In this case, the thermal expansion member 420 may be fastened to the terminal 123 with the pack bus bar 400 interposed between the thermal expansion member 420 and the terminal 123.

[0074] The thermal expansion member 420 may include a material whose volume expands when heated. For example, the thermal expansion member 420 may include one or more materials selected from the group consisting of thermal expansion resins including soft urethane, lightweight urethane, and phosphorus-based flame retardants. In this case, the thermal expansion member 420 may be formed of a foam material. However, the thermal expansion member 420 is not limited to a material that includes any of the above-listed materials, as long as it is made of a material whose volume expands when heated.

[0075] The thermal expansion member 420 may be formed so that a specific portion expands or expands in a specific direction when heated. For example, the thermal expansion member 420 may be formed so that the bottom surface expands downward when heated but the top surface does not expand, by having a lower portion made of a thermal expansion resin and an upper portion made of a heat-resistant resin that is not a thermal expansion resin.

[0076] The thermal expansion member 420 may include a first portion 421 that contacts the pack bus bar 400 and a second portion 422 that contacts the terminal insulating portion 312. In this case, the first portion 421 may be a horizontal portion that contacts the surface of the pack bus bar 400, and the second portion 422 may be a vertical portion that contacts the surface of the terminal insulating portion 312. It is preferable that the thermal expansion member 420 maximally covers the gap between the exposed portion of the first plate 31 and the second plate 32 and the terminal 123.

[0077] The terminal 123, the pack bus bar 400, and the thermal expansion member 420 may have a first fastening hole 123H, a second fastening hole 400H, and a third fastening hole 420H that penetrate vertically therethrough, respectively. In this case, the battery module may include a fastening member 410 that simultaneously penetrates the first fastening hole 123H, the second fastening hole 400H, and the third fastening hole 420H.

[0078] The fastening member 410 may include a head portion 411 interfering with the thermal expansion member 420 and a body portion 412 passing through the first fastening hole 123H, the second fastening hole 400H, and the third fastening hole 420H. The head portion 411 may have a larger diameter in the horizontal direction than the third fastening hole 420H. The body portion 412 may be engaged with a fixing portion 313 provided on the end plate 3 for fixation. For example, the fastening member 410 may be a bolt having a male thread at its lower end, and the fixing portion 313 may be a nut having a female thread attached to the first plate 31, with the outer circumferential surface of the lower end of the fastening member 410 and the inner circumferential surface of the fixing portion engaging with each other for fixation. Thus, the pack bus bar 400 and the thermal expansion member 420 may be pressed inward in the vertical direction between the head portion 411 and the terminal 123 to be fastened to the terminal 123.

[0079] However, the fastening between the terminal 123, the pack bus bar 400 and the thermal expansion member 420 is sufficient as long as the terminal 123 and the pack bus bar 400 are electrically connected to each other and the thermal expansion member 420 is fixed on the terminal 123, and does not necessarily have to be performed according to the above specific method.

[0080] According to this embodiment, the terminal 123 may be provided with the first fastening hole 123H, and the pack bus bar 400 having the second fastening hole 400H and the thermal expansion member 420 having the third fastening hole 420H may be sequentially stacked on the terminal 123, and the fastening member 410 may be a bolt having the head portion 411 with a larger diameter than the third fastening hole 420H and may include the body portion 412 having a male thread at its lower end, and the body portion 412 may be engaged with and fixed to the fixing portion 313 having a female thread on its inner surface, thereby fastening the pack bus bar 400 and the thermal expansion member 420 to the terminal 123. In this case, the thermal expansion member 420 may be made of a foam material containing a thermal expansion resin selected from soft urethane, lightweight urethane, and phosphorus-based flame retardant, and may be formed to include the first portion 421 formed horizontally to contact the surface of the pack bus bar 400, and the second portion 422 formed vertically to contact the surface of the terminal insulating portion 312.

[0081] FIG. 10 shows the expansion behavior of the thermal expansion member according to Example 1 of the present invention. Here, the arrow indicates the expansion direction of the thermal expansion member. Referring to this, if the battery cell 11 in the battery module according to this example catches fire, high-temperature gas may be discharged from the front end of the battery cell 11 where the electrode lead 111 is provided. At this time, the first plate 31 may melt due to the gas.

[0082] The thermal expansion member 420 may be heated by the gas and expand in volume. The thermal expansion member 420 expands in all directions to fill the spaces through which the gas can pass, including the space between the terminal 123 and the end plate 3, the space between the first fastening hole 123H and the fastening member 410, and the space created by melting the first plate 31. By filling the spaces through which the gas can pass, the thermal expansion member 420 may delay or prevent the gas from being discharged through the front of the battery module.

[0083] [Example 2] In the following, parts of this embodiment that are not specifically explained are the same as those of the first embodiment.

[0084] 11 and 12 are respectively an exploded perspective view and a perspective view showing the structure of a battery module according to a second embodiment of the present invention, and FIGS. 13 and 14 are respectively an enlarged partial view and a cross-sectional view showing a state in which a second plate is removed from the battery module according to the second embodiment of the present invention. Referring to these drawings, a pressure member 430 may be further fastened to the terminal 123 in addition to the pack bus bar 400 and the thermal expansion member 420.

[0085] The pressure member 430 may be fastened to the terminal 123 on the thermal expansion member 420 with the thermal expansion member 420 and the pack bus bar 400 interposed between the pressure member 430 and the terminal 123 .

[0086] The pressure member 430 may be provided to contact a portion of the surface of the thermal expansion member 420. Specifically, the bottom surface of the pressure member 430 may cover a portion of the surface of the first portion 421 of the thermal expansion member 420, which is formed in the horizontal direction, and the side surface of the pressure member 430 may cover a portion of the surface of the second portion 422 of the thermal expansion member 420, which is formed in the vertical direction. Therefore, the pressure member 430 may be formed in a shape corresponding to the surface of the thermal expansion member 420.

[0087] The pressing member 430 may be provided with a fourth fastening hole 430H penetrating vertically therethrough. In this case, the fastening member 410 may simultaneously pass through the first fastening hole 123H, the second fastening hole 400H, the third fastening hole 420H, and the fourth fastening hole 430H.

[0088] The head portion 411 may be formed to have a diameter larger than that of the fourth fastening hole 430H and may interfere with the pressing member 430. A lower end of the body portion 412 may be engaged with and fixed to the fixing portion 313. As a result, the pack bus bar 400, the thermal expansion member 420, and the pressing member 430 may be pressed inward in the vertical direction between the head portion 411 and the terminal 123 and fastened to the terminal 123.

[0089] However, the fastening between the terminal 123, the pack bus bar 400, the thermal expansion member 420, and the pressure member 430 does not necessarily have to be performed according to the above specific method, as long as the terminal 123 and the pack bus bar 400 are electrically connected to each other, and the thermal expansion member 420 is fixed on the terminal 123 and the pressure member 430 is fixed on the thermal expansion member 420.

[0090] According to this embodiment, the terminal 123 may be provided with the first fastening hole 123H, and the pack bus bar 400 having the second fastening hole 400H, the thermal expansion member 420 having the third fastening hole 420H, and the pressure member 430 having the fourth fastening hole 430H may be sequentially stacked on the terminal 123. The fastening member 410 may be a bolt having the head portion 411 with a diameter larger than that of the fourth fastening hole 430H and may include the body portion 412 having a male thread at a lower end thereof. The body portion 412 may be engaged with and fixed to the fixing portion 313 having a female thread on an inner circumferential surface thereof, thereby fastening the pack bus bar 400, the thermal expansion member 420, and the pressure member 430 to the terminal 123. In this case, the thermal expansion member 420 may be formed to include the first portion 421 formed horizontally to contact the pack bus bar 400 and the second portion 422 formed vertically to contact the terminal insulating portion 312, and the pressure member 430 may be formed in a rectangular parallelepiped shape corresponding to the thermal expansion member 420, with its bottom surface covering the surface of the first portion 421 and its side surface covering the surface of the second portion 422.

[0091] FIG. 15 shows the expansion behavior of the thermal expansion member according to Example 2 of the present invention. Here, the arrow indicates the direction of expansion of the thermal expansion member. Referring to this, if the battery cell 11 in the battery module according to this example catches fire, the pressure member 430 covers the surface of the thermal expansion member 420 and applies pressure inward, thereby suppressing the upward and forward expansion of the thermal expansion member 420 and increasing the volume of expansion downward, backward, and inward in the width direction. This allows the thermal expansion member 420 to fill the space through which the gas can pass more quickly and densely.

[0092] [Example 3] Hereinafter, the parts of this embodiment that are not specifically explained are the same as those of the first and second embodiments.

[0093] 16 and 17 are exploded and perspective views, respectively, showing the structure of a battery module according to a third embodiment of the present invention. Referring to these drawings, the battery module may include a flame-retardant cover 440 that covers the surface of the module frame 2.

[0094] The flame-retardant cover 440 may be made of a flame-retardant material. The flame-retardant cover 440 may be made of a rigid or flexible material. The flame-retardant cover 440 may cover the top surface of the module frame 2. The flame-retardant cover 440 may also cover the side surfaces of the module frame 2.

[0095] The upper surface of the flame-retardant cover 440 may be provided with a vent hole for discharging gas generated inside the module frame 2. If the flame-retardant cover 440 is made of a flexible material, the vent hole may be provided in the form of a slit. In this case, vent holes may be provided not only in the flame-retardant cover 440 but also in the upper surface of the module frame 2. By providing the vent holes in the flame-retardant cover 440 and the upper surface of the module frame 2, gas that is not discharged to the front side of the battery module can be discharged above the battery module. In this case, the vent hole provided in the flame-retardant cover 440 may be smaller than the vent hole provided in the module frame 2, which may make it easier for gas to be discharged into the battery module but more difficult for it to re-enter.

[0096] The flame-retardant cover 440 may include a pressure fixing part 441 that protrudes from a front end thereof and is fastened to the terminal 123, the pack bus bar 400, and the thermal expansion member 420. The pressure fixing part 441 may be made of a flame-retardant material and may be made of a rigid or flexible body. Alternatively, the pressure fixing part 441 may have a reinforced structure in which a rigid body is bonded to a flexible body.

[0097] The battery module may include neither the pressing member 430 nor the pressing fixing part 441, or may include both the pressing member 430 and the pressing fixing part 441. Alternatively, the pressing fixing part 441 may be integral with the pressing member 430 or may replace the pressing member 430.

[0098] When both the pressure member 430 and the pressure fixing part 441 are provided, the pressure fixing part 441 may be disposed above the pressure member 430 or below the pressure member 430 .

[0099] Although the present embodiment exemplifies a case in which the pressure member 430 and the pressure fixing portion 441 are provided as separate entities, it can be easily understood from the following explanation that the means for solving the problem of the present invention can be applied as is even when the pressure member 430 and the pressure fixing portion 441 are integral with or connected to each other, as described above.

[0100] A fifth fastening hole 441H may be formed in the pressure fixing portion 441, penetrating vertically therethrough. In this case, the fastening member 410 may simultaneously pass through the first fastening hole 123H, the second fastening hole 400H, the third fastening hole 420H, the fifth fastening hole 441H, and the fourth fastening hole 430H.

[0101] When the pressure member 430 is provided on the pressure fixing portion 441, as in Example 2, the head portion 411 of the fastening member 410 interferes with the pressure member 430, and the lower end of the body portion 412 is fixed to the fixing portion 313, thereby applying vertical inward pressure to the pack bus bar 400, the thermal expansion member 420, the pressure member 430, and the pressure fixing portion 441 between the head portion 411 and the terminal 123, thereby fastening the pack bus bar 400 to the terminal 123.

[0102] When the pressing member 430 is not present or the pressing fixing portion 441 is provided on the pressing member 430, the head portion 411 may be formed to have a diameter larger than the fifth fastening hole 441H and may interfere with the pressing fixing portion 441. A lower end of the body portion 412 may be engaged with and fixed to the fixing portion 313. As a result, the pack bus bar 400, the thermal expansion member 420, the pressing member 430, and the pressing fixing portion 441 may be pressed vertically inward between the head portion 411 and the terminal 123 and fastened to the terminal 123.

[0103] However, the fastening between the terminal 123, the pack bus bar 400, the thermal expansion member 420, the pressure member 430, and the pressure fixing portion 441 does not necessarily have to be performed according to the above specific method, as long as the terminal 123 and the pack bus bar 400 are electrically connected to each other, and the thermal expansion member 420 is fixed on the terminal 123, and the pressure member 430 and / or the pressure fixing portion 441 are fixed on the thermal expansion member 420.

[0104] According to this embodiment, the terminal 123 may be provided with the first fastening hole 123H, and the pack bus bar 400 with the second fastening hole 400H provided therein, the thermal expansion member 420 with the third fastening hole 420H provided therein, the pressure fixing portion 441 that protrudes from the front end of the flame-retardant cover 440 that is made of a flexible flame-retardant material and covers the upper surface and both side surfaces of the module frame 2, and that is provided with the fifth fastening hole 441H, and the fourth fastening hole 43 The pressure members 430 having the fourth fastening holes 430H may be stacked sequentially, and the fastening member 410 may be a bolt having the head portion 411 with a larger diameter than the fourth fastening hole 430H, and may include the body portion 412 having a male thread at its lower end, and the body portion 412 may be engaged with and fixed to the fixing portion 313 having a female thread on its inner circumferential surface, thereby fastening the pack bus bar 400, the thermal expansion member 420, and the pressure members 430 to the terminal 123. In this case, the thermal expansion member 420 may be formed to include the first portion 421 formed horizontally to contact the pack bus bar 400 and the second portion 422 formed vertically to contact the terminal insulating portion 312, and the pressure member 430 may be formed in a rectangular parallelepiped shape corresponding to the thermal expansion member 420, with its bottom surface covering the surface of the first portion 421 and its side surface covering the surface of the second portion 422.

[0105] According to this embodiment, the pressure member 430 and the pressure fixing part 441 cover the surface of the thermal expansion member 420 and apply pressure inward, thereby suppressing the upward and forward expansion of the thermal expansion member 420 and increasing the volume of the thermal expansion member 420 expanding downward, backward, and inward in the width direction. This allows the thermal expansion member 420 to fill the space through which the gas can pass more quickly and densely.

[0106] At this time, heat transfer between the battery modules may be delayed by the flame-retardant cover 440. The flame-retardant cover 440 may not be separated from the module frame 2 even if the pressure of the battery module increases suddenly, because the pressure fixing part 441 is fastened to the terminal 123 via the fastening member 410.

[0107] The present invention also provides a battery pack incorporating a battery module according to any of the embodiments of the present invention, including Examples 1 to 3, and a vehicle structure incorporating the battery pack.

[0108] FIG. 18 shows a battery pack incorporating a battery module according to the present invention, and FIG. 19 shows a vehicle incorporating the battery pack of FIG. 18. Referring to these drawings, a plurality of the battery modules (M) can be incorporated into a single pack frame to form a high-voltage and / or high-capacity battery pack (P). Within the battery pack (P), the battery modules (M) may be arranged facing each other in the front-rear direction. In this case, the plurality of pack bus bars 400 can electrically connect the plurality of terminals 123 provided on the plurality of battery modules (M) in series or parallel to each other. The battery pack (P) can be incorporated as an energy source for vehicles (V), including electric vehicles and hybrid vehicles.

[0109] According to the present invention, even if the battery module (M) catches fire, the heat transfer between the battery modules (M) is delayed or prevented, so that thermal runaway of the battery pack (P) unit is delayed or prevented, thereby improving the safety of the automobile (V).

[0110] 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.

[0111] 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 various modifications may 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 in the above description of 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]

[0112] 1 Battery cell stack 11 Battery Cells 111 Electrode lead 12 Busbar frame 121 Slit 122 module busbar Terminal 123 123H 1st fastening hole 2 Module Frame 3 End Plate 31 Plate 1 311 Terminal 1 Exposed Exit 312 Terminal insulation part 313 Fixed part 32 Second Plate 321 Terminal 2 Exposed Exit 400 pack busbars 400H 2nd fastening hole 410 Fastening members 411 Head 412 Body 420 Thermal expansion members 420H 3rd fastening hole 421 Part 1 422 Part 2 430 Pressure member 430H 4th fastening hole 440 Flame-retardant cover 441 Pressure fixing part 441H 5th fastening hole M Battery Module P Battery pack V Automobile X Length direction / Front-to-back direction Y width direction / horizontal direction Z height direction / up and down direction

Claims

1. a battery cell stack; a bus bar frame connected to the front of the battery cell stack and having terminals; a module frame having an open front and accommodating the battery cell stack; an end plate that covers the front of the module frame and has a terminal exposure opening through which the terminals are exposed to the outside; and a thermal expansion member fastened together with the terminal; The thermal expansion member expands when heated. Battery module.

2. a pack bus bar interposed between the terminal and the thermal expansion member and fastened together with the terminal and the thermal expansion member; The battery module according to claim 1 .

3. The thermal expansion member is provided above the terminal. The battery module according to claim 2 .

4. the terminal, the pack bus bar, and the thermal expansion member each include a first fastening hole, a second fastening hole, and a third fastening hole that vertically penetrate the terminal, the pack bus bar, and the thermal expansion member, respectively; a fastening member passing through the first fastening hole, the second fastening hole, and the third fastening hole simultaneously to fasten the terminal, the pack bus bar, and the thermal expansion member to one another; The battery module according to claim 3 .

5. The fastening member is a head portion that interferes with the thermal expansion member, The lower end of the fastening member is engaged with a fixing portion provided on the end plate to be fixed. The battery module according to claim 4 .

6. The end plate is a first plate made of a synthetic resin material and having a first terminal exposure opening; and a second plate, which is made of a metal material and is disposed on an outer side of the first plate in a longitudinal direction, and has a second terminal exposure hole formed therein; The battery module according to claim 2 .

7. the first plate includes a terminal insulating portion exposed to the outside through the second terminal exposure hole, The thermal expansion member is a first portion in contact with the pack busbar; and a second portion in contact with the terminal insulating portion; The battery module according to claim 6 .

8. a pressure member fastened to the thermal expansion member together with the thermal expansion member and the terminal, The battery module according to claim 2 .

9. the terminal, the pack bus bar, the thermal expansion member, and the pressure member each include a first fastening hole, a second fastening hole, a third fastening hole, and a fourth fastening hole that vertically penetrate the terminal, the pack bus bar, the thermal expansion member, and the pressure member, respectively; a fastening member that simultaneously passes through the first fastening hole, the second fastening hole, the third fastening hole, and the fourth fastening hole to fasten the terminal, the pack bus bar, the thermal expansion member, and the pressure member to one another; The battery module according to claim 8 .

10. The fastening member is a head portion that interferes with the pressure member, The lower end of the fastening member is engaged with a fixing portion provided on the end plate to be fixed. The battery module according to claim 9 .

11. The pressure member is made of a flame-retardant material. The battery module according to claim 8 .

12. The pressure member is formed in a shape corresponding to the thermal expansion member, covers a part of the surface of the thermal expansion member, and applies pressure inward. The battery module according to claim 8 .

13. a flame-retardant cover that covers the surface of the module frame; and a pressure fixing portion that projects from a front end of the flame retardant cover and is fastened to the thermal expansion member and the terminal on the thermal expansion member; The battery module according to claim 2 .

14. the terminal, the pack bus bar, the thermal expansion member, and the pressure fixing portion each include a first fastening hole, a second fastening hole, a third fastening hole, and a fifth fastening hole that vertically penetrate the terminal, the pack bus bar, the thermal expansion member, and the pressure fixing portion, respectively; a fastening member passing through the first fastening hole, the second fastening hole, the third fastening hole, and the fifth fastening hole simultaneously to fasten the terminal, the pack bus bar, the thermal expansion member, and the pressure fixing portion together; The battery module according to claim 13.

15. The fastening member is a head portion that interferes with the pressure fixing portion, A lower end of the fastening member is engaged with a fixing portion provided on the end plate and fixed. The battery module according to claim 14.

16. The pressure fixing part is formed in a shape corresponding to the thermal expansion member, covers a part of the surface of the thermal expansion member, and applies pressure inward. The battery module according to claim 13.

17. The thermal expansion member is made of a foam material containing a material selected from the group consisting of soft urethane, light urethane, light polyurethane, and thermal expansion resins containing phosphorus-based flame retardants. The battery module according to claim 1 .

18. A battery pack including a plurality of battery modules according to any one of claims 2 to 16, the plurality of terminals are electrically connected to one another in series or in parallel via the plurality of pack bus bars; Battery pack.

19. 19. A battery pack comprising: car.

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