Battery module and battery pack including same

Abstract

A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells, each including an electrode assembly, are stacked; a module frame that houses the battery cell stack; and at least one flame-retardant pad interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame, wherein the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the electrode assembly.

Description

[Technical field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0110448 filed on August 31, 2020, and Korean Patent Application No. 10-2021-0114614 filed on August 30, 2021, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery module and a battery pack including the same, and more particularly to a battery module and a battery pack including the same in which heat transfer between cells is delayed or blocked to improve safety. [Background technology]

[0003] Secondary batteries, which have high applicability according to product groups and electrical properties such as high energy density, are widely used not only in portable devices but also in electric vehicles or hybrid vehicles driven by electrical sources, power storage devices, etc. Such secondary batteries are attracting attention as a new energy source for improving energy efficiency, not only because they have the primary advantage of dramatically reducing the use of fossil fuels, but also because they are environmentally friendly in that they do not produce any by-products associated with energy use.

[0004] While small mobile devices use one or more battery cells per device, medium to large devices such as automobiles require high output and large capacity, and therefore use medium to large battery modules in which multiple battery cells are electrically connected.

[0005] Since medium- to large-sized battery modules are preferably manufactured with a lightweight and thin structure if 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. Meanwhile, the battery module may include a frame member that covers the upper, lower, left, and right sides of the battery cell stack and stores the battery cell stack in an internal space in order to protect the cell stack from external impact, heat, or vibration.

[0006] As such, since the battery cells contained within the battery module have a structure in which multiple battery cells are stacked, if a problem such as thermal runaway occurs in one of the battery cells, there is a problem that the heat and flames generated from that cell are likely to spread to adjacent battery cells. Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a battery module and a battery pack including the same that can suppress a chain reaction of combustion by delaying or blocking the propagation of a problem such as thermal runaway to adjacent battery cells even if a problem occurs in any one battery cell inside the battery module.

[0008] However, the problem to be solved by the embodiments of the present invention is not limited to the above problem, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0009] A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells, each of which includes an electrode assembly, are stacked, a module frame that houses the battery cell stack, and at least one flame-retardant pad interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame, wherein an area of ​​the flame-retardant pad is equal to or greater than an area of ​​the electrode assembly.

[0010] At least two flame-retardant pads may be included, and one or more battery cells may be positioned between two adjacent flame-retardant pads among the flame-retardant pads.

[0011] The spacing between the flame retardant pads may be the same or different.

[0012] The flame retardant pad may include a silicone foam pad.

[0013] The flame retardant pad may include two silicone foam pads and a mica sheet sandwiched between the two silicone foam pads.

[0014] The silicone foam pad may further include a coating film formed on one surface of the silicone foam pad.

[0015] The coating film may include at least one of polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), and polycarbonate (PC).

[0016] The surface of the silicone foam pad may be formed with a fine pattern.

[0017] The silicone foam pad may further include a fire-resistant inorganic filler that fills the interior pores.

[0018] The refractory inorganic filler may include at least one of calcium carbonate (CaCO3), mica, glass fiber, and mineral fiber composites.

[0019] The Silicone Foam Pad may further include Extinguishing Agents that fill the interior pores.

[0020] The extinguishing agent may be one or more selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates.

[0021] The silicone foam pad may further include a flame retardant filler material filling the interior pores.

[0022] The flame retardant filler may be one or more selected from the group consisting of nano bismuth oxide, aluminum oxide nano powder, and organic nano clay.

[0023] The area of ​​the flame-retardant pad may be equal to or larger than the area of ​​the negative electrode included in the electrode assembly.

[0024] The flame-retardant pad may not overlap a portion where an electrode lead connected to the electrode assembly is disposed.

[0025] The silicone foam pad may be halogen-free.

[0026] The flame-retardant pad may further include a heat insulating and fireproofing member formed on at least one surface of the silicone foam pad.

[0027] The heat insulating and fireproofing member may include at least one selected from a glass fiber reinforced pad (GFRP) and a carbon fiber reinforced pad (CFRP).

[0028] The silicone foam pads may include at least one first silicone foam pad and at least one second silicone foam pad, the first silicone foam pad having a higher density than the second silicone foam pad.

[0029] The silicone foam pad may include a first silicone foam pad and two second silicone foam pads disposed on either side of the first silicone foam pad with the first silicone foam pad therebetween.

[0030] The silicone foam pad may include a second silicone foam pad and two first silicone foam pads disposed on either side of the second silicone foam pad with the second silicone foam pad therebetween.

[0031] The flame-retardant pad may further include a foam coating layer formed on at least one surface of the silicone foam pad.

[0032] The foam coating layer may expand upon an increase in the ambient temperature.

[0033] A battery pack according to another embodiment of the present invention may include at least one battery module as described above, and a pack case packaging the at least one battery module. Effect of the Invention

[0034] According to an embodiment, by including a flame-retardant pad between battery cells, even if a problem such as thermal runaway occurs in one battery cell inside the battery module, the propagation of heat and flame to adjacent battery cells can be delayed or blocked, thereby suppressing a chain reaction of combustion and improving the safety of the module. [Brief description of the drawings]

[0035] [Figure 1] 1 is a perspective view showing a battery module according to an embodiment of the present invention; [Figure 2a] FIG. 2 is a cross-sectional view taken along line AA' in FIG. [Figure 2b] FIG. 2 is a cross-sectional view taken along line AA' in FIG. [Diagram 3] 2 is a perspective view showing one battery cell included in the battery cell stack of FIG. 1. [Figure 4] 4 is a diagram showing a cross section of the battery cell taken along line BB' in FIG. 3 and a cross section of a flame-retardant pad. [Diagram 5] FIG. 5 is a top view of the battery cell and the flame-retardant pad of FIG. 4. [Figure 6] FIG. 6 is an enlarged view of part C in FIG. 5. [Figure 7] 1 is a graph showing experimental results of thermal runaway for one embodiment of the present invention and a comparative example. [Figure 8] FIG. 4 shows a flame retardant pad according to a second embodiment of the present invention. [Figure 9] FIG. 13 shows a flame-retardant pad according to a third embodiment of the present invention. [Figure 10] FIG. 13 shows a flame-retardant pad according to a fourth embodiment of the present invention. [Figure 11] FIG. 13 shows a flame-retardant pad according to a fifth embodiment of the present invention. [Figure 12] FIG. 13 shows a flame-retardant pad according to a sixth embodiment of the present invention. [Figure 13] FIG. 13 shows a flame-retardant pad according to a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in various different forms and should not be construed as being limited to the embodiments set forth herein.

[0037] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0038] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown. In the drawings, thicknesses are exaggerated to clearly express multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0039] In addition, when a part such as a layer, film, region, or plate is said to be "on" or "above" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. In addition, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the opposite direction of gravity.

[0040] Also, throughout the specification, when a part "comprises" a certain element, this means that it may further include other elements, but not excluding other elements, unless specifically stated to the contrary.

[0041] Also, throughout the specification, "in a plane" means when the subject part is viewed from above, and "in cross section" means when the subject part is cut vertically and viewed from the side.

[0042] A battery module according to an embodiment of the present invention will be described with reference to FIGS.

[0043] FIG. 1 is a perspective view showing a battery module according to one embodiment of the present invention, FIGS. 2a and 2b are views showing a cross-section along A-A' in FIG. 1, FIG. 3 is a perspective view showing one battery cell included in the battery cell stack of FIG. 1, FIG. 4 is a view showing a cross-section cut along line B-B' of the battery cell of FIG. 3 and a cross-section of a flame-retardant pad, FIG. 5 is a view showing the battery cell and flame-retardant pad from above in FIG. 4, and FIG. 6 is an enlarged view of portion C of FIG. 5.

[0044] 1, 2a and 2b, a battery module 100 according to this embodiment includes a battery cell stack 101 including a plurality of battery cells 110, a module frame 120 that houses the battery cell stack 101, and end plates 130 located on the front and rear surfaces of the battery cell stack 101, respectively.

[0045] The module frame 120 may be a metal plate type module frame 120 with an integrated upper surface, lower surface, and both side surfaces, as shown in Fig. 1. That is, in the case of a rectangular tube type module frame 120, a space capable of accommodating the battery cell stack 101 is formed inside, and end plates 130 are coupled to both ends of the rectangular tube type. However, this is not limited thereto, and various types of module frames 120 may be applied. As a possible modified example, a module frame 120 in which an upper cover and a U-shaped frame are combined may also be used, and is not particularly limited thereto.

[0046] The battery cell stack 101 includes a plurality of battery cells 110 stacked in one direction, and the plurality of battery cells 110 may be stacked in an upright configuration parallel to the sidewall 124 of the module frame 120 as shown in Figures 2a and 2b.

[0047] The battery cell 110 is preferably a pouch-type battery cell. For example, referring to FIG. 3, the battery cell 110 according to the present embodiment has a structure in which two electrode leads 111 and 112 face each other and protrude from one end 114a and the other end 114b of a battery body 113, respectively. The electrode lead included in each battery cell 110 is a positive electrode lead or a negative electrode lead, and the electrode leads 111 and 112 of each battery cell 110 can be bent in one direction at their ends, thereby abutting with the ends of the electrode leads 111 and 112 of the adjacent battery cell 110. The two abutting electrode leads 111 and 112 are fixed to each other by welding or the like, thereby electrically connecting the battery cells 110 inside the battery cell stack 101. In addition, the electrode leads aligned at both ends of the battery cell stack 101 can be coupled to a bus bar frame (not shown) and electrically connected to the bus bars mounted on the bus bar frame. End plates 130 are provided on both open sides of the module frame 120 to cover the bus bar frames, and may be coupled to the module frame 120 by a method such as welding.

[0048] The battery cell 110 can be manufactured by bonding both ends 114a, 114b of the case 114 and both side faces 114c connecting the ends 114a, 114b with the electrode assembly 121 housed in the battery case 114. In other words, the battery cell 110 according to this embodiment has a total of three sealing parts 114sa, 114sb, 114sc, and the sealing parts 114sa, 114sb, 114sc are structured to be sealed by a method such as heat fusion, and the remaining other side part is formed by the connecting part 115.

[0049] An electrode assembly 121 and an electrolyte are accommodated inside the battery case 114. The electrode assembly 121 may be configured in such a way that a positive electrode plate and a negative electrode plate are disposed with a separator between them. In this case, the electrode assembly 121 may have a structure in which one positive electrode plate and one negative electrode plate are wound with a separator between them, or a structure in which multiple positive electrode plates and multiple negative electrode plates are stacked with a separator between them. The positive electrode plate and the negative electrode plate are each formed as a structure in which an active material slurry is applied to an electrode current collector, and the slurry may be formed by stirring an active material, a conductive material, a binder, a plasticizer, etc., in a state where a solvent is added.

[0050] In the electrode assembly 121, there may be uncoated areas where no slurry is applied to the electrode plates, and electrode tabs corresponding to the respective electrode plates are formed in the uncoated areas. At this time, two electrode leads 111 and 112 extending from the positive and negative electrode tabs, respectively, for electrical connection with an external terminal or device may face each other and protrude from one end 114a and the other end 114b of the battery body 113, respectively.

[0051] A thermally conductive resin layer 200 is positioned between the battery cell stack 101 and the bottom of the module frame 120. The thermally conductive resin layer 200 may transfer heat generated from the battery cell stack 101 to the bottom of the battery module 100 and also serve to fix the battery cell stack 101 to the bottom.

[0052] 2a and 2b, a plurality of flame-retardant pads 400 are interposed between the battery cells 110. As shown in FIG. 2a, a plurality of flame-retardant pads 400 are inserted one by one every time three or four battery cells 110 are stacked, and the plurality of flame-retardant pads 400 are arranged at equal intervals. Also, as shown in FIG. 2b, a plurality of flame-retardant pads 400 may be arranged at different intervals. The arrangement of the flame-retardant pads 400 is not particularly limited, and the number and thickness of the flame-retardant pads 400 may be appropriately adjusted as necessary. By arranging the flame-retardant pads 400 at equal or unequal intervals as described above, when a thermal runaway occurs in the battery cell 110 in the battery module 100, thermal impedance is increased, and heat transfer between adjacent battery cells 110 can be prevented or delayed. Also, a flame-retardant pad 400 may be arranged between the battery cell 110 stacked on the outermost side of the battery cell stack 101 and the side wall 124. When an issue such as thermal runaway occurs within the battery module 100, the flame-retardant pad 400 can delay or block the transfer of heat from a corresponding battery cell to an adjacent battery cell, and can also absorb and control the expansion of the battery cell 110.

[0053] The area of ​​the flame-retardant pad 400 is formed to be equal to or larger than the area of ​​the electrode assembly 121 included in the battery cell 110. If the area of ​​the flame-retardant pad 400 is smaller than the area of ​​the electrode assembly 121, uniform pressure cannot be applied to the battery cell 110, and problems such as performance degradation may occur. In particular, if swelling of the battery cell 110 occurs inside the battery module 100, the flame-retardant pad 400 can absorb the swelling, but if the area is smaller than the electrode assembly 121, it cannot absorb the swelling that occurs in the parts where the flame-retardant pad 400 is not formed.

[0054] As shown in FIG. 4, the area of ​​the electrode assembly 121 is determined by the length SE of one side of the electrode assembly, and the area of ​​the battery cell 110 is determined by the length SC of one side of the battery cell. More specifically, it is determined by the size of the negative electrode, positive electrode, and separator included in the electrode assembly 121. In the battery cell 110, the electrode assembly 121 does not occupy the entire space inside the battery case 114, but there is additional space for connection with the electrode leads 111 and 112. For example, the electrode assembly 121 may be about 90% of the area of ​​the battery cell 110. In this case, in order to effectively control the swelling of the battery cell 110, as described above, the area of ​​the flame-retardant pad 400 needs to be at least the same as the area of ​​the electrode assembly 121. If the flame-retardant pad 400 supports only an area smaller than the area of ​​the electrode assembly 121, the swelling that occurs may concentrate on a portion that does not correspond to the flame-retardant pad 400, causing damage to the battery cell 110. More specifically, it is preferable that the area is equal to or larger than the area of ​​the negative electrode constituting the electrode assembly 121. For example, in the chemical reaction of a lithium ion battery, the negative electrode must receive lithium ions from the positive electrode, so the negative electrode may be designed to be longer and wider than the positive electrode. However, if the size of the flame-retardant pad 400 is smaller than the size of the negative electrode, it is not preferable because it cannot sufficiently absorb swelling that occurs during charging and discharging.

[0055] 4 to 6, the flame-retardant pad 400 should be formed to have an area equal to or larger than that of the electrode assembly 121 included in the battery cell 110, thereby maintaining excellent swelling control performance of the battery cell 110 by the flame-retardant pad 400. In addition, it is possible to prevent the battery performance from deteriorating due to the concentration of swelling in a localized portion of the battery cell 110.

[0056] In addition, it is preferable that the size of the flame-retardant pad 400 is larger than the area of ​​the electrode assembly 121, but does not extend to the part where the electrode leads 111, 112 connected to the electrode taps extending from the electrode assembly 121 are arranged. If the flame-retardant pad 400 extends to the part where the electrode leads 111, 112 are arranged, interference occurs during an assembly process for electrical connection between the electrode leads 111, 112 and other components, which is not preferable. In addition, since there is a possibility that the contact between the flame-retardant pad 400 and the electrode leads 111, 112 may cause damage to each other, it is preferable that the size of the flame-retardant pad 400 is set so that it is not arranged in the part where the electrode leads protrude from the electrode cell 110.

[0057] The flame-retardant pad 400 may be made of a silicone foam pad to prevent the transfer of heat and flames generated in the battery cell 110. The silicone foam pad is a foam pad with pores formed therein, and has high thermal and chemical stability and excellent flame retardant and heat insulating properties. In particular, by using a silicone foam pad made of thermosetting foamed silicone, more excellent flame retardant properties can be ensured.

[0058] Furthermore, from the viewpoint of controlling the swelling of the battery cell 110 described above, the silicone foam pad can be appropriately applied since it has high elasticity (high compression resistance and resilience) and high durability. In particular, the battery cell 110 repeatedly contracts and expands due to the swelling of the battery cell 110, and high elasticity is required to withstand this and prevent deformation, etc., and for this purpose, a silicone foam pad can be used. Specifically, the silicone foam pad can have a compression repulsion force of 10 to 100 kPa in a compression range (Compression Force Deflection, CFD) of 10 to 60%, and preferably has a long recovery guarantee life (durability) of 10 years or more.

[0059] In addition, in the case of the silicone foam pad, it is preferable that the content of hydrocarbons is low in order to minimize the collapse of the structure due to combustion under the condition of thermal runaway of the battery cell 110. That is, the weight loss of the flame-retardant pad increases and the structure may collapse due to the hydrocarbons being pyrolyzed into gas phase such as CO, CO2, and water vapor by the combustion reaction under the condition of thermal runaway of the battery cell, so it is preferable that the content of hydrocarbons in the silicone foam pad is adjusted to be as low as possible. Also, it is preferable that the silicone foam pad does not contain halogen elements in order not to generate toxic gases during combustion.

[0060] An experiment was carried out on the battery module 100 using such a silicone foam pad as the flame-retardant pad 400 and on a battery module not using the flame-retardant pad 400 to determine the time point at which the voltage drops when thermal runaway occurs.

[0061] FIG. 7 is a graph showing the experimental results of thermal runaway for one embodiment of the present invention and a comparative example.

[0062] In the embodiment, a battery module including 12 battery cells was constructed by applying a flame-retardant pad to every 6 battery cells, for a total of 2 flame-retardant pads, and in the comparative example, a battery module was constructed by applying a polyurethane pad instead of the flame-retardant pad with the same configuration. A heating pad was attached to the end of the battery module to heat the battery module, and a voltage was applied to the heating pad to start heating, and thermal runaway occurred at about 140 seconds after the start of heating, and the point at which the voltage of the entire battery module dropped was measured.

[0063] As a result, it was confirmed that the battery module voltage became 0 at about 300 seconds in the comparative example, but the voltage became 0 at about 420 seconds in the embodiment, as shown in Fig. 7. That is, it was confirmed that according to the embodiment of the present invention, the transfer of heat from a cell in which thermal runaway has occurred to an adjacent cell is appropriately delayed or blocked, and the point in time at which the voltage drops due to thermal runaway can be delayed as much as possible.

[0064] As described above, according to the present embodiment, by providing the flame-retardant pads 400 between the battery cells 110 of the battery module 100, it is possible to delay or block the transfer of heat to adjacent battery cells when thermal runaway occurs, thereby improving the safety of the battery. Furthermore, by making the area of ​​the flame-retardant pads 400 the same as or larger than the area of ​​the electrode assembly 121, it is possible to prevent problems such as damage to the battery cells and electrodes and reduced performance / life caused by the formation of uneven surface pressure between the battery cells.

[0065] Such a flame-retardant pad 400 can be modified into various shapes and applied to the battery module 100. Hereinafter, flame-retardant pads according to second and third embodiments of the present invention will be described with reference to FIGS.

[0066] FIG. 8 is a view showing a flame-retardant pad according to a second embodiment of the present invention, and FIG. 9 is a view showing a flame-retardant pad according to a third embodiment of the present invention.

[0067] 8, a flame-retardant pad 401 according to a second embodiment of the present invention includes two silicone foam pads 410 and further includes a mica sheet 420 interposed between the two silicone foam pads 410. By applying the flame-retardant pad 401 further including the mica sheet 420 having excellent heat resistance between the silicone foam pads 410, it is possible to more effectively prevent the structure of the silicone foam pad 410 from collapsing due to pyrolysis under thermal runaway conditions.

[0068] As shown in FIG. 9, the flame-retardant pad 402 according to the third embodiment of the present invention further includes a coating film 430 formed on the silicone foam pad 410. The coating film 430 can be applied to improve process ease and reduce friction between the flame-retardant pad 402 and the battery cells 110 when manufacturing the battery cell stack 101 of the battery module 100. The coating film 430 can be attached to the silicone foam pad 410 by an adhesive or the like. The coating film 430 can be made of at least one of polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), and polycarbonate (PC), but is not particularly limited thereto.

[0069] In another modified example, a silicone foam pad having a fine pattern formed on its surface can be used as the flame-retardant pad 400. By forming the fine pattern, it is possible to prevent external foreign matter from adhering to the flame-retardant pad 400 and to obtain a desired degree of friction. The shape and size of the fine pattern are not particularly limited.

[0070] In another modified example, the pores inside the silicone foam pad used as the flame-retardant pad 400 can be controlled to impart various properties to the flame-retardant pad 400. That is, when manufacturing the silicone foam pad, the ratio and size of the pores can be adjusted (i.e., density can be adjusted) by adjusting the ratio of the foaming agent and the curing agent added, and at this time, the higher the pore density, the more the thermal insulation properties can be improved, and the lower the pore density, the more the mechanical properties can be improved. By appropriately adjusting this, a silicone foam pad having desired thermal insulation properties and mechanical properties can be obtained.

[0071] In addition, the physical properties of the silicone foam pad can be reinforced by filling the pores in the silicone foam pad with various additional materials. The additional materials can be mixed with the foaming agent and the curing agent to form the silicone foam pad and added to the inside of the silicone foam pad.

[0072] For example, in order to reinforce the heat resistance of the silicone foam pad, a refractory inorganic filler can be added to the pores inside the silicone foam pad. The refractory inorganic filler can include at least one of calcium carbonate (CaCO3), mica, glass fiber, and mineral fiber composite.

[0073] In addition, a flame-retardant filler may be added to the pores inside the silicone foam pad so that the silicone foam pad has flame retardant or self-extinguishing properties. The flame-retardant filler may be at least one of nano bismuth oxide, aluminum oxide nano powder, and organic nano clay, but is not limited thereto. By adding the flame-retardant filler, the silicone foam pad can have flame retardancy that meets the UL (Underwriter's Laboratory) standard.

[0074] On the other hand, by filling the pores inside the silicone foam pad with an extinguishing agent, carbon dioxide gas is released under thermal runaway conditions, thereby imparting a self-extinguishing function that can suppress the combustion reaction itself. As such an extinguishing agent, one or more selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates can be used, but is not particularly limited.

[0075] According to another embodiment of the present invention, a flame-retardant pad having better flame retardancy, heat insulation, and mechanical properties can be provided by reinforcing various additional properties in a silicone foam pad used as a flame-retardant pad, and thus, when a thermal runaway condition occurs in a battery module, the transfer of heat can be more effectively delayed or blocked to suppress a combustion reaction.

[0076] Hereinafter, flame-retardant pads according to fourth to seventh embodiments of the present invention will be described with reference to FIGS.

[0077] FIG. 10 is a view showing a flame-retardant pad 403 according to a fourth embodiment of the present invention. As shown in FIG. 10, the flame-retardant pad 403 according to the fourth embodiment of the present invention further includes a flame-retardant heat insulating member 440 formed on the surface of a silicon foam pad 410. The flame-retardant heat insulating member 440 can prevent the flame from spreading when a fire occurs, and can also prevent the heat from spreading to adjacent cells due to its heat insulating performance even if a thermal runaway occurs in one cell and the temperature becomes high. In particular, the flame-retardant heat insulating member 440 made of a material different from that of the silicon foam pad 410 is further added to the surface of the silicon foam pad 410, so that the spread of flame and heat between adjacent cells can be more reliably blocked. The flame-retardant heat insulating member 440 can be formed on one or both sides of the silicon foam pad 410, or can be added to the inner layer of the silicon foam pad 410. However, it is preferable to attach the flame-retardant heat insulating member 440 to both sides of the silicon foam pad 410 as shown in FIG. 10 so that the flame-retardant heat insulating member 440 is in direct contact with the silicon foam pad 410 when heat and flame occur in the battery cell, since the spread of flame and heat can be more effectively prevented. At least one selected from a glass fiber reinforced pad (GFRP) and a carbon fiber reinforced pad (CFRP) can be used as the fire-retardant heat insulating member 440. By using a configuration including at least one fire-retardant heat insulating member 440 formed on the surface of the silicone foam pad 410 as the fire-retardant pad 403, the spread of heat and flame to adjacent cells under thermal runaway conditions can be more effectively blocked.

[0078] 11 and 12 are diagrams showing flame-retardant pads 404 and 405 according to the fifth and sixth embodiments of the present invention. As shown in FIG. 11 and FIG. 12, the flame-retardant pads 404 and 405 according to the fifth and sixth embodiments of the present invention include multi-layered silicone foam pads 410a and 410b. Specifically, the pads include at least one first silicone foam pad 410a and at least one second silicone foam pad 410b. At this time, the density of the first silicone foam pad 410a is higher than that of the second silicone foam pad 410b. The first silicone foam pad 410a and the second silicone foam pad 410b may have a configuration in which the first silicone foam pad 410a is disposed in the center and the second silicone foam pad 410b is disposed on both sides as shown in FIG. 11, or may have a configuration in which the second silicone foam pad 410b is disposed in the center and the first silicone foam pad 410a is disposed on both sides as shown in FIG. 12. By using both the high-density and low-density silicone foam pads 410a and 410b in this manner, the flame-retardant pads 404 and 405 can effectively control the expansion of the battery cells while effectively delaying or blocking the transfer of heat. That is, the first high-density silicone foam pad 410a is advantageous in more effectively delaying or blocking the transfer of heat under thermal runaway conditions, but may be somewhat disadvantageous in controlling the expansion of the cells. However, by providing the second low-density silicone foam pad 410b in addition, it has a buffering effect against the expansion of the battery cells, and therefore the expansion of the battery cells can also be effectively controlled. The density of the silicone foam pads 410a and 410b can be controlled by adjusting the size and number of the internal pores, but is not limited thereto.

[0079] FIG. 13 is a view showing a flame-retardant pad 406 according to a seventh embodiment of the present invention. As shown in FIG. 13, the flame-retardant pad 406 according to the seventh embodiment of the present invention further includes a foam coating layer 450 formed on the surface of a silicone foam pad 410. The foam coating layer 450 has a property of expanding when a thermal runaway occurs inside the battery cell and the temperature rises rapidly. As a result, the space between the cells is expanded, and when exposed to high temperatures, the flame-retardant pad 406 secures a space that can insulate between the cells, so that the transfer of heat can be more effectively delayed or blocked. As the foam coating layer 450, a coating of a foam material that reacts to temperature can be appropriately selected and used. For example, a flame-retardant material containing phosphorus can be used, and the foam coating layer 450 undergoes an endothermic decomposition reaction at high temperatures to expand the coating, thereby securing a space between the cells and forming a carbonized layer that is porous and thermally stable with very low thermal conductivity, thereby blocking or delaying the transfer of heat.

[0080] As described above, according to the fourth to seventh embodiments of the present invention, a flame-retardant pad that can absorb the swelling of the battery cells more effectively while having better flame retardancy (fireproofing) and heat insulation can be provided by adding an additional layer to the silicone foam pad used in the flame-retardant pad or by changing the physical properties of the silicone foam pad. Therefore, while effectively controlling the swelling of the battery cells due to the rise in temperature within the battery module, it is possible to more effectively delay or block the transfer of heat and suppress the combustion reaction even under thermal runaway conditions at high temperatures.

[0081] Meanwhile, one or more battery modules according to the embodiments of the present invention may be packaged in a pack case to form a battery pack.

[0082] The battery module and the battery pack including the battery module may be applied to various devices, such as vehicles including electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto and may be applied to various devices in which the battery module and the battery pack including the battery module can be used, which also fall within the scope of the present invention.

[0083] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0084] 100 Battery Module 110 Battery Cell 120 module frame 121 Electrode assembly 400 Flame Retardant Pad

Claims

1. a battery cell stack in which a plurality of battery cells, each of which includes an electrode assembly, are stacked; a module frame that houses the battery cell stack; and at least one flame-retardant pad is interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame; the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the electrode assembly; the flame retardant pad comprises a silicone foam pad; The battery module, wherein the flame-retardant pad includes two silicone foam pads and a mica sheet interposed between the two silicone foam pads.

2. The battery module of claim 1 , wherein the at least two flame-retardant pads are included, and one or more battery cells are positioned between two adjacent flame-retardant pads among the flame-retardant pads.

3. The battery module according to claim 2 , wherein the spacing between the flame-retardant pads is the same or different.

4. a battery cell stack in which a plurality of battery cells, each of which includes an electrode assembly, are stacked; a module frame that houses the battery cell stack; and at least one flame-retardant pad is interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame; the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the electrode assembly; the flame retardant pad comprises a silicone foam pad; The battery module, wherein a fine pattern is formed on a surface of the silicone foam pad.

5. A battery module as described in claim 4, further comprising a coating film formed on one side of the silicone foam pad.

6. The battery module according to claim 5, wherein the coating film includes at least one of polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), and polycarbonate (PC).

7. a battery cell stack in which a plurality of battery cells, each of which includes an electrode assembly, are stacked; a module frame that houses the battery cell stack; and at least one flame-retardant pad is interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame; the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the electrode assembly; the flame retardant pad comprises a silicone foam pad; The silicone foam pad further comprises a fire-resistant inorganic filler filling the interior pores; The refractory inorganic filler is calcium carbonate (CaCO ３ ), mica, glass fiber, and mineral fiber composite.

8. a battery cell stack in which a plurality of battery cells, each of which includes an electrode assembly, are stacked; a module frame that houses the battery cell stack; and at least one flame-retardant pad is interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame; the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the electrode assembly; the flame retardant pad comprises a silicone foam pad; The battery module, wherein the silicone foam pad further includes an extinguishing agent that fills internal pores.

9. The battery module according to claim 8 , wherein the extinguishing agent is at least one selected from the group consisting of inorganic carbonates, inorganic phosphates, and inorganic sulfates.

10. a battery cell stack in which a plurality of battery cells, each of which includes an electrode assembly, are stacked; a module frame that houses the battery cell stack; and at least one flame-retardant pad is interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame; the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the electrode assembly; the flame retardant pad comprises a silicone foam pad; the silicone foam pad further comprises a flame-retardant filler material filling the interior pores; The battery module, wherein the flame-retardant filler is at least one selected from the group consisting of nano-bismuth oxide, aluminum oxide nano-powder, and organic nano-clay.

11. The battery module of claim 1 , wherein the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the negative electrode included in the electrode assembly.

12. The battery module of claim 1 , wherein the flame-retardant pad does not overlap a portion where an electrode lead connected to the electrode assembly is disposed.

13. A battery module described in any one of claims 1 to 12, wherein the silicone foam pad does not contain halogen elements.

14. a battery cell stack in which a plurality of battery cells, each of which includes an electrode assembly, are stacked; a module frame that houses the battery cell stack; and at least one flame-retardant pad is interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame; the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the electrode assembly; the flame retardant pad comprises a silicone foam pad; The flame-retardant pad further includes a heat insulating and fireproofing member formed on at least one surface of the silicone foam pad, The heat insulating and fireproofing member includes at least one selected from a glass fiber reinforced pad (GFRP) and a carbon fiber reinforced pad (CFRP).

15. a battery cell stack in which a plurality of battery cells, each of which includes an electrode assembly, are stacked; a module frame that houses the battery cell stack; and at least one flame-retardant pad is interposed at least in one of between adjacent battery cells among the plurality of battery cells and between the battery cell stack and the module frame; the area of ​​the flame-retardant pad is equal to or greater than the area of ​​the electrode assembly; the flame retardant pad comprises a silicone foam pad; the silicone foam pads include at least one first silicone foam pad and at least one second silicone foam pad; The density of the first silicone foam pad is higher than the density of the second silicone foam pad.

16. The battery module of claim 15 , wherein the silicone foam pad comprises a first silicone foam pad and two second silicone foam pads disposed on both sides of the first silicone foam pad with the first silicone foam pad therebetween.

17. The battery module of claim 15 , wherein the silicone foam pad comprises a second silicone foam pad and two first silicone foam pads disposed on both sides of the second silicone foam pad with the second silicone foam pad therebetween.

18. The battery module of claim 1 , wherein the flame-retardant pad further comprises a foam coating layer formed on at least one surface of the silicone foam pad.

19. The battery module of claim 18 , wherein the foam coating layer expands upon an increase in ambient temperature.

20. At least one battery module according to any one of claims 1 to 19; and A battery pack including a pack case that packages the at least one battery module.

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