Battery module and battery pack including cooling unit

Abstract

A battery pack according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a frame that houses the battery cell stack, and a cooling unit on the battery cell stack, the cooling unit including a refrigerant receiving member including an upper plate and a lower plate, an elastic member disposed in an internal space of the refrigerant receiving member, and a sealing member that seals at least one through-hole formed in the lower plate of the refrigerant receiving member and is meltable due to an increase in temperature of the battery cells, and a refrigerant is received in the space between the elastic member and the lower plate of the refrigerant receiving member, and the elastic member expands as the refrigerant is received.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0088259 dated July 18, 2022 and Korean Patent Application No. 10-2023-0092581 dated July 17, 2023, 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 a cooling section, and more particularly to a battery module and a battery pack that prevent thermal runaway. [Background technology]

[0003] Secondary batteries have been attracting attention as a power source for electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, etc., which have been presented as a solution to air pollution caused by existing vehicles that use fossil fuels and diesel vehicles.

[0004] Small mobile devices use one, two, three, or four battery cells per device, whereas medium to large devices such as automobiles use medium to large battery modules in which a large number of battery cells are electrically connected due to the need for high output and large capacity.

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

[0006] The battery cells constituting such medium- to large-sized battery modules are composed of secondary batteries that can be charged and discharged, and such high-output, large-capacity secondary batteries generate a large amount of heat during the charging and discharging process.

[0007] If the heat generated in the battery module during charging and discharging cannot be effectively removed, heat accumulation occurs, which accelerates the deterioration of the battery module and may even lead to fire or explosion. Therefore, a medium-sized or large battery pack for a vehicle or a medium-sized or large battery pack for a power storage device, which includes multiple medium-sized or large battery modules and is a high-output, large-capacity battery, requires a cooling system for cooling the battery cells contained therein.

[0008] 14 and 15 are vertical cross-sectional views of a battery module or battery pack 10 according to the prior art. Referring to Fig. 14, a refrigerant (cooling water) stored in a refrigerant receiving member 220 (water tank) is supplied to the ignited battery cell 103 through a through hole 230, and the pressure of the refrigerant (water pressure) in the refrigerant receiving member 220 gradually decreases. Therefore, the speed at which the refrigerant is injected into the battery cell 103 slows down over time.

[0009] In addition, the pressure of the refrigerant inside the refrigerant receiving member 220 is roughly proportional to the height of the refrigerant, but since the refrigerant receiving member 220 (water tank) is usually formed along the direction in which the battery cell stack is housed, the height of the refrigerant receiving member 220 is smaller than its width, which means that the pressure of the refrigerant injected into the battery cells 103 will be even lower. This is a factor that hinders rapid injection of the refrigerant.

[0010] In addition, if a vehicle equipped with a battery pack is positioned on an inclined surface, etc., and the refrigerant receiving member 220 of the battery pack is also positioned at an incline, it may occur that not all of the refrigerant in the refrigerant receiving member 220 can be supplied to the battery cell stack, as shown in Figure 15.

[0011] 14 and 15, the coolant is supplied by gravity from the upper coolant receiving member 220 to the lower battery cell stack along the open through-hole 230. Therefore, the coolant receiving member 220 can only be located at the upper part of the battery cell stack, and there is a restriction that the coolant receiving member 220 cannot be provided at the lower part. Figures 14 and 15 show a case where no coolant receiving space is provided at the lower part, and only a heat sink 211 is provided. Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention is intended to solve such problems, and in order to prevent thermal energy from being transferred to adjacent battery cells when a battery cell ignites or explodes, a refrigerant for a cooling section provided inside a battery module and / or a battery pack can be quickly and directly injected into the ignited battery cell.

[0013] In addition, it is possible to provide a battery module and / or a battery pack including a cooling unit having a structure that can minimize the increase in volume of the battery module and / or the battery pack while overcoming the constraint of difficult injection of the refrigerant on a slope and efficiently suppress the thermal runaway phenomenon of the battery cells.

[0014] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0015] A battery pack according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a frame that houses the battery cell stack, and a cooling unit on the battery cell stack, the cooling unit including a refrigerant receiving member including an upper plate and a lower plate, an elastic member disposed in an internal space of the refrigerant receiving member, and a sealing member that seals at least one through-hole formed in the lower plate of the refrigerant receiving member and is meltable due to an increase in temperature of the battery cells, and a refrigerant is received in a space between the elastic member and the lower plate of the refrigerant receiving member, and the elastic member can expand as the refrigerant is received.

[0016] The elastic member may be in the form of a film and cover a bottom plate of the refrigerant receiving member including the at least one through hole.

[0017] When the sealing member melts due to the temperature rise of the battery cell, the elastic member can pressurize the refrigerant and supply the refrigerant to the battery cell laminate.

[0018] When the refrigerant is supplied to the battery cell laminate and the pressure by which the refrigerant pressurizes the elastic member gradually decreases, the elastic member can gradually contract.

[0019] The periphery of the film-shaped elastic member may be fixed to the periphery of the lower plate of the refrigerant receiving member or the vicinity thereof.

[0020] After the periphery of the elastic member is interposed between the peripheries of the upper plate and the lower plate of the refrigerant receiving member, it may be subjected to seaming processing, or the peripheries of the upper plate and the lower plate of the refrigerant receiving member may be embossed, and after the periphery of the elastic member is interposed therebetween, it may be mechanically fastened.

[0021] Before the melting of the sealing member, the elastic member can expand to the maximum inside the refrigerant receiving member.

[0022] The lower plate of the refrigerant receiving member may be a heat dissipation plate.

[0023] The refrigerant receiving member has a structure integrated with the frame, and the upper plate of the refrigerant receiving member can constitute a part of the frame.

[0024] The refrigerant receiving member may have a structure for storing the refrigerant.

[0025] The refrigerant receiving member is a water tank, and the refrigerant may be cooling water.

[0026] The refrigerant receiving member includes an outflow / inflow port through which the refrigerant flows in and out, and the outflow / inflow port may be located in the space between the lower plate of the refrigerant receiving member and the elastic member.

[0027] The coolant receiving member may further include at least one partition disposed in the internal space to separate the internal space into a plurality of sections, the at least one partition disposed perpendicular to the one surface of the coolant receiving member and in a longitudinal direction of the battery cell, and the elastic member may be provided individually across each of the plurality of sections.

[0028] The sealing member may be made of a thermoplastic polymeric resin.

[0029] The elastic member may have a melting point higher than a melting point of the sealing member.

[0030] The elastic member may be made of a material that is waterproof and capable of contracting and expanding.

[0031] The elastic member may have a double structure in which a waterproof fabric is surrounded by a band-shaped member capable of contracting and expanding.

[0032] The cooling portion may be disposed on at least one of an upper surface and a lower surface of the battery cell stack.

[0033] The frame may include an upper plate of the frame disposed on an upper side of the battery cell stack, a lower plate of the frame disposed on a lower side of the battery cell stack, and a side plate of the frame disposed on a side of the battery cell stack between the upper and lower plates, and the lower plate of the coolant receiving member may be disposed at a predetermined distance from the frame to form the coolant receiving member.

[0034] A battery pack according to another embodiment of the present invention may include a plurality of the battery cell stacks, and the cooling unit may be disposed on the plurality of battery cell stacks. Effect of the Invention

[0035] As described above, the battery module and / or battery pack of the present invention contains a refrigerant in the internal space of the cooling section and is equipped with an elastic member that can contract and expand, so that in the event of a battery cell catching fire, the battery cell can be quickly cooled.

[0036] Furthermore, even if the coolant receiving space is disposed at an angle, all of the coolant within the coolant receiving space can be supplied to the ignited battery cell.

[0037] In addition, the increase in the volume of the battery module and / or the battery pack can be minimized, and the thermal runaway phenomenon of the battery cells can be efficiently suppressed.

[0038] Additionally, when the sealing member attached to the cooling unit melts due to high battery cell temperature, the cooling unit directly injects coolant into the battery cell, thereby quickly lowering the temperature of the battery cell. [Brief description of the drawings]

[0039] [Figure 1] FIG. 1 is a schematic diagram of a battery module or a battery pack according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a vertical cross-sectional view of a battery module or battery pack according to one embodiment of the present invention. [Diagram 3] FIG. 3 shows a case where the battery cell is cooled by the elastic member provided in the cooling section of FIG. 2 when the battery cell catches fire. [Figure 4] FIG. 4 is a vertical sectional view of a battery module or a battery pack according to another embodiment of the present invention. [Diagram 5] FIG. 5 is a plan view of an embodiment of a heat sink that can be applied to the cooling portion of FIGS. [Figure 6] FIG. 6 is a partially enlarged view of FIG. [Figure 7] FIG. 7 is an enlarged vertical cross-sectional view of a battery module or battery pack in which a sealing member is added to a heat sink having a groove formed therein. [Figure 8]FIG. 8 is a vertical cross-sectional view of a grooved heat sink with a sealant added thereto. [Figure 9] FIG. 9 is a schematic diagram of the upper plate, heat sink plate, coolant receiving member, and elastic member of the battery module or battery pack of FIG. [Figure 10] FIG. 10 is a conceptual diagram showing one example of a method for fixing the periphery of the elastic member shown in FIG. [Figure 11] FIG. 11 is a conceptual diagram showing another example of a method for fixing the periphery of the elastic member shown in FIG. [Figure 12] FIG. 12 is a schematic diagram showing a battery pack according to an embodiment of the present invention in which a plurality of battery cell stacks (cell module assemblies) are housed. [Figure 13] FIG. 13 is a vertical cross-sectional view of the battery pack of FIG. 12 according to one embodiment of the present invention, illustrating the inclusion of a cooling element above the multiple battery cell stack of FIG. [Figure 14] FIG. 14 is a vertical cross-sectional view of a battery module or battery pack according to the prior art. [Figure 15] FIG. 15 is a vertical cross-sectional view of a battery module or battery pack according to the prior art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] 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.

[0041] 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. In the drawings, thicknesses are enlarged to clearly express various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0042] 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 direction opposite to gravity.

[0043] In addition, throughout the specification, when a part is said to "comprise" a certain element, this does not mean to exclude other elements, but means that the part may further include other elements, unless specifically stated to the contrary.

[0044] Also, throughout the specification, the term "on a plane" means when the part in question is viewed from above, and the term "on a cross section" means when the part in question is cut vertically and viewed from the side.

[0045] In addition, because the top / bottom or upper / lower surfaces of a particular component can be determined differently depending on which direction is used as the reference, throughout this specification, "top" and "bottom" refer to two surfaces that face each other on the z-axis of the component, and "top" and "bottom" are defined as surfaces that are opposite each other on the z-axis of the component.

[0046] FIG. 1 is a schematic diagram of a battery module or a battery pack according to the present invention.

[0047] The battery module or battery pack referred to in the present specification differs only in scale, but is the same in that at least one surface of the upper and lower parts of the battery cell stack is provided with a cooling portion, which will be described in detail below.

[0048] Referring to FIG. 1, a battery module or battery pack 100 according to the present invention includes a frame that houses a battery cell stack 101 in which a plurality of battery cells are stacked, and cooling units arranged on the upper and lower surfaces of the battery cell stack 101.

[0049] 1 shows bidirectional pouch-type battery cells in which electrode leads 102 protrude in opposite directions, but it goes without saying that unidirectional pouch-type battery cells in which positive and negative leads protrude in the same direction can also be used. In addition, the battery cells may be pouch-type battery cells, but the present invention is not limited to the above and can be modified in various ways, such as being applicable to rectangular battery cells or cylindrical battery cells.

[0050] The frame of the battery module or battery pack (hereinafter referred to as the "frame") includes an upper plate 110 arranged on the upper part of the battery cell stack 101, a lower plate 120 arranged on the lower part of the battery cell stack 101, and a side plate 130 arranged between the upper plate 110 and the lower plate 120 and arranged on a side of the battery cell stack 101.

[0051] Furthermore, an end plate (not shown) may be combined with the upper plate 110, the lower plate 120 and the side plate 130 on the outer side of the protruding electrode lead 102 of the battery cell to assemble a frame.

[0052] In addition, the shape of the frame is not limited to the structure shown in Fig. 1, and the frame may be a monoframe or a U-frame, unlike that shown in Fig. 1. That is, in some cases, the upper plate 110 may not be provided separately, and the upper surface of a cooling part, which will be described later, may replace the upper plate of the frame.

[0053] FIG. 2 is a vertical cross-sectional view of a battery module or battery pack according to one embodiment of the present invention.

[0054] Referring to FIG. 2, a battery module or battery pack includes a battery cell stack 101, in which a plurality of battery cells are stacked, housed within a frame including an upper plate 110 and a lower plate 120.

[0055] The cooling unit 200a includes a coolant receiving member 220 that receives a coolant. One surface of the coolant receiving member 220 is disposed on at least one surface of the battery cell stack 101. The one surface of the coolant receiving member 220 may be a heat sink 210. The other surface facing the one surface of the coolant receiving member 220 may be an upper plate 110.

[0056] 1 to 11, the upper plate 110, the lower plate 120, and the side plate 130 refer to the upper plate of the frame, the lower plate of the frame, and the side plate of the frame, respectively, and for convenience, are abbreviated to the upper plate 110, the lower plate 120, and the side plate 130. This should be understood as a separate concept from the upper plate of the refrigerant receiving member 220 and the lower plate of the refrigerant receiving member 220 based on the refrigerant receiving member 220.

[0057] Also, as described above, when the coolant receiving member 220 is provided on the upper part of the battery cell stack 101, the upper plate of the coolant receiving member 220 may be the upper plate of the frame (i.e., the upper plate 110). Similarly, when the coolant receiving member 220 is provided on the lower part of the battery cell stack 101, the lower plate of the coolant receiving member 220 may be the lower plate of the frame (i.e., the lower plate 120).

[0058] For convenience, the following description will be given taking the case of the upper plate 110 and the heat dissipation plate 210 as an example. The heat dissipation plate 210 is coupled to the upper plate 110 with a gap therebetween, and the space formed by the gap becomes the coolant receiving member 220. Therefore, the upper plate 110, the heat dissipation plate 210, and the coolant receiving member 220 form an integrated structure. The cooling unit 200a is coupled to the upper plate 110 as an integral unit, and is located on the top of the battery cell stack 101.

[0059] However, the present invention is not limited to the above. For example, it is not necessary for the upper plate 110 of the frame to be a component of the coolant receiving member 220 so as to form the coolant receiving member 220. There is no problem as long as the coolant receiving member 220 itself has a shape that can store a coolant, and it is sufficient if it has a shape and structure that allows it to be joined to the battery cell stack 101 via a heat sink 210 that includes a through hole 230, which will be described later.

[0060] The cooling part 200a' also includes a heat sink 210 and a coolant receiving member 220 that contains a coolant. The heat sink 210 is coupled to the lower plate 120 with a gap therebetween, and the space formed by the gap becomes the coolant receiving member 220. Therefore, the lower plate 120, the heat sink 210 and the coolant receiving member 220 form an integrated structure.

[0061] That is, cooling section 200a' is integrally connected to lower plate 120 and is located below battery cell stack 101. Similarly, lower plate 120 of the frame does not necessarily have to form refrigerant receiving member 220. There is no problem as long as refrigerant receiving member 220 itself has a shape that stores refrigerant, and it is sufficient that it has a shape and structure that allows it to be connected to battery cell stack 101 via heat sink 210, which includes through holes 230 described below. Through holes 230 are formed in heat sink 210, and sealing member 240 is attached to through holes 230.

[0062] The sealing member 240 is made of a material that melts due to high-temperature gas or sparks emitted from the battery cells. That is, when the battery cells are in a normal state, the sealing member 240 maintains a state in which the through-hole 230 is sealed, but when the temperature rises or a fire occurs, as in the case of the battery cell 103, the sealing member 240 melts and the through-hole 230 is opened. The coolant from the coolant receiving member is directly injected into the battery cell stack 101 through the opened through-hole 230. Through this process, the overheated or ignited battery cell can be quickly cooled, quickly preventing the spread of thermal runaway.

[0063] Since the sealing member 240 is a material that melts in the presence of high-temperature gas or sparks emitted by venting of a battery cell with an increased temperature, a thermoplastic polymer resin having a melting point of about 200°C or less may be used. For example, the thermoplastic polymer resin may be a material such as polyethylene or polypropylene having a melting point of about 100°C or more and 200°C or less.

[0064] Meanwhile, when cooling water is used as a refrigerant, and considering that the cooling water is directly injected into the battery cell, it is necessary to prevent the injection of the cooling water from causing a fire or explosion in the battery cell. Therefore, it is preferable that the additive contained in the cooling water does not contain a flammable material. Alternatively, when the additive contains a flammable material, the amount of the additive may be sufficient to prevent a secondary explosion of the battery cell and to be used as an antifreeze to prevent the cooling water from freezing.

[0065] Meanwhile, the refrigerant receiving member 220 accommodates the refrigerant therein. More specifically, the cooling unit 200a according to the present invention includes an elastic member 250 capable of contracting / expanding in the internal space of the refrigerant receiving member 220. The elastic member 250 is in a film shape and is disposed across the internal space of the refrigerant receiving member 220. When the heat dissipation plate 210 includes at least one through hole 230, it is preferable that the film-shaped elastic member 250 covers at least one through hole 230. In addition, the elastic member 250 covers at least a part of the heat dissipation plate 210. Thereby, the elastic member 250 can largely divide the internal space of the refrigerant receiving member 220 into two (upper and lower in the embodiment of FIG. 2). That is, the space is divided into a space between the heat dissipation plate 210 including the through hole 230 and one surface of the elastic member 250, and a space between the other surface of the elastic member 250 and the inner wall of the refrigerant receiving member 220. The coolant is accommodated in the space between the heat sink 210 and the elastic member 250, including the through hole 230, within the internal space of the coolant receiving member 220.

[0066] The periphery of the elastic member 250 may be fixed to the periphery of one surface of the coolant receiving member 220 that is disposed adjacent to the battery cell stack. That is, in the embodiment of FIG. 2, the elastic member 250 may be fixed to a portion where the coolant receiving member 220 and the heat sink 210 come into contact. Alternatively, the periphery of the elastic member 250 may be fixed to the inner wall of the coolant receiving member 220. Examples of a method of fixing the periphery of the elastic member 250 to a portion where the periphery of the elastic member 250 comes into contact with the inner wall of the coolant receiving member 220 or the upper plate 110 and / or the heat sink 210 will be described later with reference to FIG. 9 to FIG. 11. However, in order to supply all of the coolant received inside the elastic member 250 to the battery cell stack 101 through the through hole 230 as the elastic member 250 contracts, as described later, it is preferable that the elastic member 250 be located on the side of the inner wall of the coolant receiving member 220 that is closer to the heat sink 210. Alternatively, the periphery of the elastic member 250 may be fixed to the heat sink 210, and the refrigerant may be received in the space between the heat sink 210 and the elastic member 250. The embodiment of Fig. 2 shows a case where the refrigerant is received in the elastic member 250 to the maximum extent and the refrigerant expands to the maximum extent.

[0067] The refrigerant receiving member 220 may be a water tank that stores the refrigerant therein, or may have a structure including an inlet and outlet (not shown) through which the refrigerant flows in and out. When the refrigerant receiving member 220 has a structure through which the refrigerant flows in and out, the elastic member 250 has a structure that covers not only the through-hole 230 but also the inlet and outlet. In other words, the inlet and outlet may be located in the space between the elastic member 250 and one side of the refrigerant receiving member where the through-hole 230 is located, and the refrigerant may flow through the inlet and outlet while the refrigerant is accommodated in the space between the elastic member 250 and one side of the refrigerant receiving member where the through-hole 230 is located.

[0068] The high-temperature gas or sparks emitted from the battery cells 103 due to the increased temperature of the battery cell stack 101 melt the sealing member 240 attached to the through-hole 230 of the heat sink 210. Therefore, the coolant contained in the space between the heat sink 210, including the through-hole 230, and the elastic member 250 is supplied to the battery cells 103 via the opened openings 255 and the opened through-holes 230.

[0069] As shown in Fig. 2, the elastic member 250 is expanded to the maximum extent by the internal pressure of the refrigerant, and as shown in Fig. 3, the refrigerant received inside the elastic member 250 is released, and the pressure applied by the refrigerant to the elastic member 250 gradually decreases, causing the elastic member 250 to gradually contract. Unlike the case of Fig. 14 relating to the prior art, the refrigerant in the elastic member 250 located in the refrigerant receiving member 220 can be supplied to the battery cells 103 at a faster speed due to the pressure caused by the contraction of the elastic member 250. In addition, the refrigerant that was in the space between the elastic member 250 and the heat sink 210 can be supplied to the battery cells 103 without being left behind.

[0070] The elastic member 250 is made of a material that has elasticity to enable contraction and expansion, and is as unlikely to be damaged by high-temperature gas or sparks emitted from the battery cells 103. In addition, since the elastic member 250 contains a refrigerant therein, it is made of a material that has chemical resistance to the refrigerant (cooling water, etc.).

[0071] The elastic member 250 may be made of a material that is waterproof and can contract and expand. For example, a polymer resin, rubber, or silicone film that can contract and expand and has a waterproof function may be used. As an example, the elastic member 250 may be in the form of a rubber film made of rubber.

[0072] Alternatively, the elastic member 250 may have a double structure in which a waterproof fabric is surrounded by a band-shaped member capable of contracting and expanding. For example, the elastic member 250 may have a double structure in which a waterproof material (such as a fireproof cloth) is layered and pressed against an elastic material. As an example, the elastic member 250 may have a double structure in which a rubber band is layered and applied to a fireproof cloth.

[0073] The present invention is not limited to the above, and various modifications and variations are possible, such as one of the cooling unit 200a located on the upper part of the battery cell stack 101 and the cooling unit 200a' located on the lower part of the battery cell stack 101 only having a heat sink 210 and not having a refrigerant receiving member 220.

[0074] Fig. 4 is a vertical cross-sectional view of a battery module or a battery pack according to another embodiment of the present invention, showing a cooling unit 200b which is a partial modification of the cooling unit 200a of Fig. 2. For an explanation of components of the cooling unit 200b of Fig. 4 that overlap with those of the cooling unit 200a of Fig. 2, please refer to the explanation of Fig. 2.

[0075] 4, the partition wall 215 can vertically cross the coolant receiving member 220 to partition the internal space. The partition wall 215 can be, for example, in the form of a plate that connects the heat sink 210 and the upper plate and is arranged parallel to the side plate 130 (see FIG. 1). In such a case, the partition wall 215 can be arranged parallel to the longitudinal direction of each battery cell of the battery cell stack 101.

[0076] The coolant receiving member 220 is divided into a plurality of sections arranged in a row in the horizontal direction based on the partition wall 215. An elastic member 250 is provided in each of the plurality of sections partitioned inside the coolant receiving member 220, and a coolant is contained in each of the plurality of elastic members 250. When the temperature of the battery cell 103 rises or a fire occurs, the coolant can be supplied in several portions. For other descriptions of the elastic member 250, please refer to the descriptions above with reference to FIGS. 2 and 3.

[0077] The number of partitions 215 is not limited to that shown in FIG. 4 and may be one or more, and various modifications and variations are possible, such as a plurality of partitions 250a, depending on the environment in which the present invention is embodied.

[0078] The shape of the partition wall 215 is not necessarily a flat shape, and various modifications and changes are possible as long as it can separate and partition the internal space of the refrigerant receiving member 220. Fig. 5 shows a plan view of an embodiment of a heat sink 210 that can be applied to the cooling unit of Figs. 2 to 4. Fig. 5(a) shows a state in which a through hole 230 is formed in the heat sink 210.

[0079] Heat sink 210 has through holes 230 each having a circular shape on a plane, which are arranged at regular intervals in the horizontal and vertical directions.

[0080] The through holes must be formed at positions where cooling water can be supplied to any battery cell if the battery cell catches fire. In other words, it is preferable that at least one through hole is disposed for each battery cell so that cooling water can be supplied to all battery cells. Therefore, the number and intervals of the through holes may be adjusted according to the number and size of the battery cells.

[0081] 5(b) and 5(c) are plan views of a partially modified embodiment of the heat sink 210 of FIG. 5(a).

[0082] 5(b) and 5(c), the shape of through holes 230' and 230'' formed in the heat sink 210 is different from the shape of the through hole 230 in FIG.

[0083] When the battery cells are arranged so that the short axis direction of the heat sink 210 shown in Figures 5(b) and 5(c) is parallel to the longitudinal direction L of the battery cells, the through hole 230' is formed at an angle so that one through hole can cover two or more battery cells, and the through hole 230'' is formed in a direction perpendicular to the longitudinal direction L of the battery cells so that it can cover two or more battery cells.

[0084] In the case where such a through hole is formed, when the sealing member melts due to heat generation and explosion of any one of the battery cells, the through hole is formed large, so that cooling water can be applied to the surface of the battery cells that are adjacent to the battery cells that have not heated or exploded, thereby lowering the temperature of the battery cells that have not heated or exploded, thereby preventing the occurrence of thermal runaway.

[0085] Fig. 6 is a partially enlarged view of Fig. 2. Fig. 6 shows an enlarged view of the portion marked "A" in Fig. 2. Spaces may form between the battery cell stack 101 and the heat sink 210, and the distance between the battery cell and the heat sink 210 may vary for each individual battery cell. Spaces formed between the battery cell stack 101 and the heat sink 210 in this way reduce the heat dissipation ability of dissipating heat from inside the battery module and / or battery pack to the outside.

[0086] To prevent such problems, the space between the battery cell stack 101 and the heat sink 210 may be filled with a thermal interface material (TIM) 390.

[0087] The thermal transfer material 390 increases the thermal connection points between the battery cell stack 101 and the heat sink, so that thermal energy generated by the battery cell stack 101 can be quickly dissipated.

[0088] However, if the thermal energy released from the battery cells does not directly contact the sealing member through the heat transfer material 390, the sealing member may not reach its melting temperature. Therefore, the addition of the heat transfer material may be omitted.

[0089] Alternatively, the heat transfer material may not be formed under the through-hole of the heat sink, but may be applied only to other portions. In this case, even if the heat transfer material is applied, the thermal energy of the vented battery cell is not lost but is directly transferred to the sealing member, so that the sealing member melts and a coolant can be supplied to the vented battery cell.

[0090] Meanwhile, a sealing member 240 is attached to the through hole 230 penetrating the heat sink 210, so that, for example, the sealing member 240 fills the through hole 230 and includes an extension portion 241 that extends further outward from around the through hole 230 on the inner surface 211 of the heat sink and the outer surface 212 of the heat sink.

[0091] Since the sealing member 240 has the extension portion 241, the sealing member 240 can be prevented from being removed by the pressure of the cooling water flowing through the refrigerant receiving member, thereby preventing the through hole from being opened.

[0092] FIG. 7 is an enlarged vertical cross-sectional view of a battery module or battery pack in which a sealing member is added to a heat sink having a groove formed therein.

[0093] Referring to FIG. 7, a coolant receiving member 320 is formed between an upper plate 110 and a heat sink 310, and a sealing member 340 is attached to the through hole of the heat sink 310.

[0094] The sealing member 340 includes an extension 341, and grooves 314 are formed in the inner surface 311 of the heat sink and in the portion of the outer surface 312 of the heat sink where the extension 341 is formed.

[0095] A part of the sealing member constituting extension portion 341 is inserted into groove 314 to form insertion portion 345, which more effectively prevents the sealing member from being removed by the water pressure of the cooling water and the through hole from being opened.

[0096] In order to manufacture a sealing member including such an extension, an insert injection method may be used in which a resin for a sealing member is injected into a heat sink having a groove formed therein. Alternatively, the portion of the sealing member that passes through the through hole may be prepared by preparing a center portion of the sealing member having a shape and size corresponding to the shape and size of the through hole, and adding a separate member to the center portion of the sealing member to form the extension. In this case, the method of connecting the center portion of the sealing member and the separately added extension may be, but is not limited to, adhesion using an adhesive, screw fastening, or interference fitting. Also, the center portion of the sealing member may be made of a thermoplastic polymer resin that melts at high temperatures, and the material of the separately added extension may be made of a material that does not melt at high temperatures.

[0097] FIG. 8 is a vertical cross-sectional view of a grooved heat sink with a sealant added thereto.

[0098] Referring to FIG. 8, heat sinks 410, 510, 610 each have a sealing member 440, 540, 640 added thereto.

[0099] The heat sinks 410, 510, 610 are each formed with a groove 414, 514, 614 at a portion where the heat sink abuts against the extension, and an insertion portion 445, 545, 645 is formed inside the groove 414, 514, 614.

[0100] The vertical cross section of the heat sink 410, 510, 610 where the grooves 414, 514, 614 are formed may be formed in any one or more shapes selected from the group consisting of a polygon including a triangle, a trapezoid, etc., a semicircle, and a semi-ellipse, or may be formed in a mixture of these.

[0101] 8(c), the thickness of center portion 641 of sealing member 640 is formed to be thinner than the thickness of center portion of sealing member 410 and the thickness of center portion of sealing member 510. When the thickness of the portion sealing the through hole is formed relatively thin in this manner, the time required for the sealing member to melt and open the through hole can be shortened, so that the coolant can be quickly supplied to the battery cell.

[0102] In addition, the heat sink may constitute a refrigerant receiving member that is coupled to the upper and lower plates of the frame, and the heat sink may constitute one surface that is coupled to the upper and lower plates and the other surface that faces the other surface.

[0103] Hereinafter, a method in which the periphery of the elastic member 250 is fixed to the upper plate 110, the heat dissipation plate 210 and / or the coolant receiving member 220 will be described as an example.

[0104] Figure 9 is a schematic diagram of the upper plate, heat dissipation plate, coolant receiving member, and elastic member of the battery module or battery pack of Figure 2. First, the scales of the upper plate 110, heat dissipation plate 210, coolant receiving member 220, and elastic member 250 in Figures 2 and 9 to 11 are not limited to those shown, and may be modified and changed in various ways to suit the environment in which the present invention is embodied.

[0105] A coolant receiving member 220 is formed between the upper plate 110 and the heat dissipation plate 210 of the battery module or battery pack. In addition, an elastic member 250 is disposed to divide the inner space of the coolant receiving member 220 into two large spaces. In this case, as described above with reference to FIG. 2, the periphery of the elastic member 250 may be fixed to the inner wall of the coolant receiving member 220 or to the portion that contacts the upper plate 110 and / or the heat dissipation plate 210. In FIG. 9, the periphery of the elastic member 250 is indicated as B. Since FIG. 9 is a schematic representation of a plan view, when the battery module or battery pack is viewed three-dimensionally in the present invention, the description in FIG. 9 to FIG. 11 regarding the periphery B of the elastic member 250 can be applied to all of the front / rear and left / right peripheries of the battery module or battery pack.

[0106] FIG. 10 is a conceptual diagram showing an example of a method for fixing the periphery of the elastic member in FIG. 9 by seaming.

[0107] For example, with the periphery of the elastic member 250 interposed between the periphery of the upper plate 110 and the periphery of the heat sink 210, the periphery of the upper plate 110, the periphery of the heat sink 210, and the periphery of the elastic member 250 can all be seamed. That is, the periphery can be processed by bending, overlapping, and pressing. The shape and structure in which the periphery of the upper plate 110, the periphery of the heat sink 210, and the periphery of the elastic member 250 are seamed are not limited to those shown in FIG. 10 and can be modified and changed in various ways.

[0108] FIG. 11 is a conceptual diagram showing another example of a method for fixing the periphery of the elastic member in FIG. 9, in which embossing and mechanical fastening are combined.

[0109] For example, first, the periphery of the upper plate 110 and the periphery of the heat sink 210 are embossed to have uneven portions. The embossing process increases the roughness of the periphery of the upper plate 110 and the periphery of the heat sink 210 to prevent the elastic member 250 from slipping. The periphery of the elastic member 250 is temporarily fixed between the embossed periphery of the upper plate 110 and the periphery of the heat sink 210, and then the periphery of the upper plate 110, the periphery of the heat sink 210, and the periphery of the elastic member 250 can all be mechanically fastened together, for example, by rivets / bolts. The shape and structure of the embossed periphery of the upper plate 110 and the periphery of the heat sink 210 are not limited to those shown in FIG. 11 and can be modified and changed in various ways.

[0110] Meanwhile, the method of fixing the periphery of the elastic member is not limited to the above-described method shown in FIGS. 9 to 11, and various other processing methods can be applied after modification or alteration.

[0111] In addition, although Figures 9 to 11 illustrate the coolant receiving member 220 being provided on the upper part of the battery cell stack 101, this can also be applied to the case where the coolant receiving member 220 is provided on the lower part of the battery cell stack 101.

[0112] The above has been described with reference to the drawings focusing on a battery module or battery pack including one battery cell stack 101 according to the present invention and the cooling unit included therein, however, the cooling unit according to an embodiment of the present invention can also be applied in the same manner to a battery pack including a plurality of battery cell stacks 101 (cell module assemblies).

[0113] A case where a plurality of battery cell stacks 101 (cell module assemblies) are stacked to form a battery pack will be described with reference to Figs. 12 and 13. Fig. 12 shows a schematic diagram of a battery pack 100' according to an embodiment of the present invention in which a plurality of battery cell stacks 101 are stored. Fig. 13 is a vertical cross-sectional view of the battery pack according to an embodiment of the present invention shown in Fig. 12, showing a case where a cooling unit 200 is included on the plurality of battery cell stacks 101 shown in Fig. 12. The battery pack 100' shown in Figs. 12 and 13 shows a case where one cooling unit 200 is placed on the plurality of battery cell stacks 101. The cooling units described above in Figs. 1 to 11 can be applied in the same manner to a battery pack 100' in which a plurality of battery cell stacks 101 are stacked.

[0114] Referring to FIG. 13, a cooling unit 200 may be located on a plurality of battery cell stacks 101 (cell module assemblies).

[0115] The frame includes an upper plate 110 disposed on an upper portion of the plurality of battery cell stacks 101, a lower plate 120 disposed on a lower portion of the plurality of battery cell stacks 101, and side plates (not shown) disposed between the upper plate 110 and the lower plate 120 and disposed on both sides of the plurality of battery cell stacks 101. Additionally, a cross beam 140 may be included between the plurality of battery cell stacks 101. The shape of the frame including the upper plate 110, the lower plate 120, and the side plates is not limited to the structures shown in Figs. 12 and 13, and may be modified and changed in various ways to suit the environment in which the present invention is embodied.

[0116] 13, the upper plate 110 and the lower plate 120 respectively refer to the upper plate of the frame and the lower plate of the frame, and for convenience are abbreviated to the upper plate 110 and the lower plate 120. This should be understood as a separate concept from the upper plate of the refrigerant receiving member 220 and the lower plate of the refrigerant receiving member 220 based on the refrigerant receiving member 220.

[0117] 13, the cooling unit 200 includes a coolant receiving member 220 that receives a coolant. One surface of the coolant receiving member 220 is disposed on at least one surface of the plurality of battery cell stacks 101. One surface of the coolant receiving member 220 may be a heat sink 210. The other surface facing the one surface of the coolant receiving member 220 may be the upper plate 110 of the frame. In other words, when the coolant receiving member 220 is provided on the upper portion of the plurality of battery cell stacks 101, the upper plate of the coolant receiving member 220 may be the upper plate 110 of the frame. The heat sink 210 includes a plurality of through holes 230. The through holes 230 are sealed by a sealing member 240.

[0118] On the other hand, the refrigerant receiving member 220 of the battery pack 100' in FIG. 13 is arranged on a plurality of battery cell stacks 101, whereas the refrigerant receiving member 220a of the battery module or battery pack 100 in FIG. 2 is arranged on a single battery cell stack 101, which is a difference. However, the detailed components of the refrigerant receiving member 220 in FIG. 13 are the same as the detailed components of the refrigerant receiving member 220a of the battery module or battery pack 100 in FIG. 2.

[0119] Therefore, since the description of the detailed components of the coolant receiving member 220 in Fig. 13 overlaps with the description of the detailed components of the coolant receiving member 220a of the battery module or battery pack 100 in Fig. 2, the other descriptions should refer to those described above in Fig. 1 to Fig. 11. Also, the description of the parts marked A and B in Fig. 13 overlaps with those described in Fig. 6 and Fig. 9 to Fig. 11, respectively, so the descriptions of those parts should refer to those described above.

[0120] 13 shows the cooling unit 200 disposed above the plurality of battery cell stacks 101, various modifications and variations are possible, such as the cooling unit 200 being disposed below the plurality of battery cell stacks 101 in some cases. Of course, the partition wall 215 can also be applied to the cooling unit 220, as described above in the embodiment of FIG.

[0121] In this way, when the battery module and / or battery pack and the cooling unit included therein according to the present invention are used, even if a battery cell catches fire, the battery cell can be cooled quickly. Also, even if the refrigerant receiving space is arranged at an angle, the entire refrigerant in the refrigerant receiving space can be supplied to the ignited battery cell. The increase in the volume of the battery module and / or battery pack can be minimized, and the thermal runaway phenomenon of the battery cell can be efficiently suppressed.

[0122] Those skilled in the art will appreciate that the present invention can be applied in a variety of ways and modified within the scope of the present invention based on the above content.

[0123] 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 belong to the scope of the present invention. [Explanation of symbols]

[0124] 101: Battery cell stack 110: Upper plate 120: Lower plate 130: Side plate 200, 200a, 200a′, 200b, 200b′: Cooling section 210, 310, 410, 510, 610: Heat sink 215: Bulkhead 220, 320: refrigerant receiving member 230, 230′, 230″, 267, 267′, 330: Through hole 240, 268, 268′, 340, 440, 540, 640: sealing members 250: Elastic member

Claims

1. a battery cell stack in which a plurality of battery cells are stacked; a frame that houses the battery cell stack; a cooling portion on the battery cell stack; The cooling unit includes: a coolant receiving member including an upper plate and a lower plate; an elastic member disposed in the internal space of the refrigerant receiving member; a sealing member that seals at least one through hole formed in a lower plate of the coolant receiving member and is meltable by a temperature increase of the battery cell; A refrigerant is received in a space between the elastic member and the lower plate of the refrigerant receiving member, and the elastic member expands due to the reception of the refrigerant.

2. The battery pack according to claim 1 , wherein the elastic member is in the form of a film and covers a bottom plate of the coolant receiving member including the at least one through hole.

3. The battery pack according to claim 1 , wherein when the sealing member melts due to a temperature rise of the battery cells, the elastic member pressurizes the coolant and supplies the coolant to the battery cell stack.

4. 2 . The battery pack according to claim 1 , wherein the elastic member gradually contracts as the coolant is supplied to the battery cell stack and the pressure applied by the coolant to the elastic member gradually decreases.

5. 3. The battery pack according to claim 2, wherein a peripheral edge of the film-shaped elastic member is fixed to or near a peripheral edge of the lower plate of the coolant receiving member.

6. The periphery of the elastic member is interposed between the periphery of the upper plate and the periphery of the lower plate of the refrigerant receiving member, and then seamed; 6. The battery pack according to claim 5, wherein the periphery of each of the upper and lower plates of the coolant receiving member is embossed, and the periphery of the elastic member is interposed therebetween, and then mechanically fastened.

7. The battery pack according to claim 1 , wherein the elastic member expands to a maximum extent inside the coolant-receiving member before the sealing member melts.

8. The battery pack according to claim 1 , wherein the lower plate of the coolant receiving member is a heat sink.

9. The battery pack of claim 1 , wherein the coolant receiving member is an integral structure with the frame, and a top plate of the coolant receiving member forms a part of the frame.

10. The battery pack according to claim 1 , wherein the coolant receiving member is a structure for storing the coolant.

11. The battery pack according to claim 1 , wherein the coolant receiving member is a water tank, and the coolant is cooling water.

12. The battery pack according to claim 1 , wherein the coolant receiving member includes an inlet through which the coolant flows, the inlet being located in a space between a lower plate of the coolant receiving member and the elastic member.

13. at least one partition disposed in the interior space of the refrigerant receiving member to divide the interior space into a plurality of zones; the at least one partition wall is disposed perpendicular to the one surface of the coolant receiving member and is disposed in a longitudinal direction of the battery cell; 2. The battery pack of claim 1, wherein the elastic member is provided individually across each of the plurality of regions.

14. 2. The battery pack according to claim 1, wherein the sealing member is made of a thermoplastic polymer resin.

15. The battery pack according to claim 1 , wherein the elastic member has a melting point higher than a melting point of the sealing member.

16. 2. The battery pack according to claim 1, wherein the elastic member is made of a material that is waterproof and capable of contracting and expanding.

17. 2. The battery pack according to claim 1, wherein the elastic member has a double structure in which a waterproof fabric is surrounded by a band-shaped member capable of contracting and expanding.

18. The battery pack according to claim 1 , wherein the cooling portion is disposed on at least one of an upper surface and a lower surface of the battery cell stack.

19. The frame is an upper plate of a frame disposed on an upper side of the battery cell stack; a lower plate of a frame disposed on a lower side of the battery cell stack; a side plate of a frame disposed on a side of the battery cell stack between the upper plate and the lower plate, The battery pack according to claim 1 , wherein the lower plate of the coolant receiving member is spaced apart from the frame by a predetermined distance to form the coolant receiving member.

20. A plurality of the battery cell stacks are provided, The battery pack according to claim 1 , wherein the cooling portion is disposed on the plurality of stacked battery cells.

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