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 of related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0088259 filed on July 18, 2022 and Korean Patent Application No. 10-2023-0092581 filed on July 17, 2023, and all the contents disclosed in the documents of the Korean patent application are included as part of this specification.

[0002] The present invention relates to a battery module and a battery pack including a cooling unit, and specifically, to a battery module and a battery pack for preventing a thermal runaway phenomenon.

Background Art

[0003] Secondary batteries have been attracting attention as power sources for electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, etc., which are proposed as solutions for solving air pollution such as existing vehicles using fossil fuels, diesel vehicles, etc.

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

[0005] Medium and large-sized battery modules are preferably manufactured with a small size and weight if possible, so square batteries, pouch-type batteries, etc. that can be stacked with a high degree of integration and have a small weight-to-capacity ratio are mainly used as battery cells of medium and large-sized battery modules.

[0006] Since the battery cells constituting such a medium and large-sized battery module are composed of secondary batteries capable of charge and discharge, such high-output and large-capacity secondary batteries generate a large amount of heat during the charge and discharge process.

[0007] If the heat generated in a battery module during the charging and discharging process cannot be effectively removed, heat buildup occurs, which can accelerate the degradation of the battery module and, in some cases, induce ignition or explosion. Therefore, medium- and large-sized battery packs for vehicles and power storage devices, which contain multiple medium- and large-sized battery modules and are high-power, high-capacity batteries, require a cooling system to cool the battery cells contained within them.

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

[0009] Furthermore, while the pressure of the refrigerant in the refrigerant receiving member 220 is generally proportional to the height of the refrigerant, the refrigerant receiving member 220 (water tank) is usually formed along the direction in which the battery cell stack is housed. Therefore, its height is lower than its width, which inevitably leads to an even lower pressure of the refrigerant injected into the battery cells 103. This hinders the rapid injection of refrigerant.

[0010] Furthermore, if a vehicle equipped with a battery pack is located on an inclined surface, and the refrigerant receiving member 220 of the battery pack is also inclined, then, as shown in Figure 15, it may not be possible to supply all of the refrigerant in the refrigerant receiving member 220 to the battery cell stack.

[0011] Furthermore, as shown in Figures 14 and 15, the refrigerant is supplied by gravity from the upper refrigerant receiving member 220 to the lower battery cell stack along the open through-hole 230. Therefore, the refrigerant receiving member 220 can only be located at the top of the battery cell stack, and there is a constraint that a refrigerant receiving member 220 cannot be provided at the bottom. Figures 14 and 15 show the case where a refrigerant receiving space cannot be provided at the bottom, and only a heat sink 211 is provided. [Overview of the project] [Problems that the invention aims to solve]

[0012] The present invention solves these problems by allowing a cooling refrigerant provided inside the battery module and / or battery pack to be quickly and directly injected into the ignited battery cell in order to prevent the transfer of thermal energy to adjacent battery cells when a battery cell ignites and explodes.

[0013] Furthermore, it is possible to provide a battery module and / or battery pack that includes a cooling unit with a structure that can overcome the constraint that it is difficult to inject refrigerant on an incline, minimize the increase in volume of the battery module and / or battery pack, and efficiently suppress thermal runaway phenomena of the battery cells.

[0014] However, the problems that the embodiments of the present invention aim to solve are not limited to those described above, and can be broadly 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 for housing the battery cell stack, and a cooling section on the battery cell stack, wherein the cooling section includes a refrigerant receiving member including an upper plate and a lower plate, an elastic member disposed in the 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 by the temperature rise of the battery cells, wherein a refrigerant is received in the space between the elastic member and the lower plate of the refrigerant receiving member, and the elastic member can expand as a result of the refrigerant being received.

[0016] The elastic member is in the shape of a membrane and can cover the lower plate of the refrigerant receiving member, which includes 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, seaming processing may be performed, or the peripheries of the upper plate and the lower plate of the refrigerant receiving member are 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 maximally inside the refrigerant receiving member.

[0022] The lower plate of the refrigerant receiving member may be a heat radiating 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 inlet through which the refrigerant flows in and out, and the outflow inlet may be located in the space between the lower plate of the refrigerant receiving member and the elastic member.

[0027] including at least one partition disposed in the internal space so as to separate the internal space of the refrigerant receiving member into a plurality of regions, the at least one partition being disposed perpendicular to the one surface of the refrigerant receiving member and disposed in the longitudinal direction of the battery cell, and the elastic member may be individually provided across each of the plurality of regions.

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

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

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

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

[0032] The cooling part may be disposed on at least one of the upper surface and the lower surface of the battery cell laminate.

[0033] The frame includes an upper plate of the frame disposed on the upper side of the battery cell laminate, a lower plate of the frame disposed on the lower side of the battery cell laminate, and a side plate of the frame disposed on the side surface of the battery cell laminate between the upper plate and the lower plate, and the lower plate of the refrigerant receiving member is disposed at a predetermined distance from the frame and may form the refrigerant receiving member.

[0034] The battery pack according to another embodiment of the present invention includes a plurality of the battery cell laminates, and the cooling part may be disposed on the plurality of battery cell laminates.

Advantages of the Invention

[0035] As described above, the battery module and / or battery pack according to the present invention can rapidly cool a ignited battery cell when it ignites by housing a coolant in the internal space of the cooling section and providing an elastic member that can contract and expand.

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

[0037] Furthermore, it minimizes the increase in volume of the battery module and / or battery pack, while efficiently suppressing thermal runaway phenomena in the battery cells.

[0038] Additionally, when the sealing material attached to the cooling section melts due to the high temperature of the battery cell, the refrigerant is injected directly into the battery cell in the cooling section, allowing the temperature of the battery cell to be rapidly lowered. [Brief explanation of the drawing]

[0039] [Figure 1] Figure 1 is a schematic diagram of a battery module or battery pack according to one embodiment of the present invention. [Figure 2] Figure 2 is a vertical cross-sectional view of a battery module or battery pack according to one embodiment of the present invention. [Figure 3] Figure 3 shows a case where the battery cell is cooled by the elastic member provided in the cooling section of Figure 2 when the battery cell catches fire. [Figure 4] Figure 4 is a vertical cross-sectional view of a battery module or battery pack according to another embodiment of the present invention. [Figure 5] Figure 5 is a plan view of an embodiment of a heat sink applicable to the cooling section shown in Figures 2 to 4. [Figure 6] Figure 6 is a magnified view of a portion of Figure 2. [Figure 7] Figure 7 is a magnified vertical cross-sectional view of a battery module or battery pack in which a sealing member is attached to a heat sink with grooves formed in it. [Figure 8]Figure 8 is a vertical cross-sectional view of a heat sink with grooves formed on it and a sealing member attached. [Figure 9] Figure 9 is a schematic diagram of the upper plate, heat sink, coolant receiving member, and elastic member of the battery module or battery pack shown in Figure 2. [Figure 10] Figure 10 is a conceptual diagram illustrating an example of a method for fixing the periphery of the elastic member shown in Figure 9. [Figure 11] Figure 11 is a conceptual diagram illustrating another example of a method for fixing the periphery of the elastic member shown in Figure 9. [Figure 12] Figure 12 schematically shows a battery pack according to one embodiment of the present invention, in which multiple battery cell stacks (cell module assemblies) are housed. [Figure 13] Figure 13 is a vertical cross-sectional view of a battery pack according to one embodiment of the present invention shown in Figure 12, showing a case in which a cooling unit is included on top of the stack of battery cells shown in Figure 12. [Figure 14] Figure 14 is a vertical cross-sectional view of a conventional battery module or battery pack. [Figure 15] Figure 15 is a vertical cross-sectional view of a conventional battery module or battery pack. [Modes for carrying out the invention]

[0040] The present invention will be described in detail below, with reference to the attached drawings, so that various embodiments may be easily implemented by a person with ordinary skill in the art to which the invention pertains. The present invention can be embodied in various different forms and is not limited to the embodiments described herein.

[0041] Furthermore, the dimensions and thicknesses of each component shown in the drawings are arbitrary for the sake of explanation, and therefore the present invention is not necessarily limited to those shown. The thicknesses are shown enlarged in the drawings to clearly represent various layers and regions. In addition, the thicknesses of some layers and regions are exaggerated in the drawings for the sake of explanation.

[0042] Furthermore, when we say that a layer, membrane, region, plate, or other part is "on top of" or "on top of" another part, this includes not only the case where it is "directly above" the other part, but also the case where the other part is in between. Conversely, when we say that one part is "directly above" another part, it means that there is no other part in between. Also, when we say that a part is "on top of" or "on top of" a reference part, it means that it is located above or below the reference part, and does not necessarily mean that it is located "on top of" or "on top of" in the opposite direction of gravity.

[0043] Furthermore, when a specification states that a certain part "includes" a certain component, unless otherwise specified, this does not mean that other components are excluded, but rather that other components may be included.

[0044] Furthermore, throughout the specification, "on a plane" means when the subject is viewed from above, and "on a cross-section" means when the subject is viewed from the side of a cross-section obtained by cutting the subject perpendicularly.

[0045] Furthermore, since the top / bottom or upper / lower parts of a particular component can be determined differently depending on the direction used as a reference, throughout this specification, "top" and "bottom" refer to two faces of the component on the z-axis, while "upper part" and "lower part" refer to parts of the component that are located in opposite directions on the z-axis.

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

[0047] The battery module or battery pack as defined in the specification of this invention is identical in that it is provided with a cooling section, as described in detail below, on at least one surface of the upper and lower parts of the battery cell stack, except for differences in scale.

[0048] Referring to Figure 1, the 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 that are arranged on the upper and lower surfaces of the battery cell stack 101.

[0049] As an example of multiple battery cells, Figure 1 shows a bidirectional pouch-type battery cell in which the electrode leads 102 protrude in opposite directions from one another. However, it goes without saying that a unidirectional pouch-type battery cell in which the positive electrode lead and negative electrode lead protrude in the same direction from one another can also be used. Furthermore, while the battery cell may be a pouch-type battery cell, the present invention is not limited to those described above, and various modifications and changes are possible, such as being applicable to prismatic or cylindrical battery cells.

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

[0051] Furthermore, an end plate (not shown) may be attached to the upper plate 110, lower plate 120, and side plate 130 on the outside of the direction in which the electrode leads 102 of the battery cell protrude, thereby assembling the frame.

[0052] Furthermore, the frame configuration is not limited to the structure shown in Figure 1. A monoframe or U-frame configuration may be used, differing from that shown in Figure 1. In other words, in some cases, the upper plate 110 may not be provided separately, and the upper surface of the cooling section (described later) may serve as the upper plate of the frame.

[0053] Figure 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 Figure 2, the battery module or battery pack houses a battery cell stack 101, which consists of multiple battery cells stacked on top of each other, within a frame that includes an upper plate 110 and a lower plate 120.

[0055] The cooling section 200a includes a refrigerant receiving member 220 that contains a refrigerant. One surface of the refrigerant receiving member 220 is positioned on at least one surface of the battery cell stack 101. The other surface of the refrigerant receiving member 220 facing the other surface may be an upper plate 110.

[0056] For reference, in Figures 1 to 11, the upper plate 110, lower plate 120, and side plate 130 refer to the upper plate, lower plate, and side plate of the frame, respectively, and for convenience, they are abbreviated as upper plate 110, lower plate 120, and side plate 130. These must be understood as separate concepts from the upper plate and lower plate of the refrigerant receiving member 220, which are based on the refrigerant receiving member 220.

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

[0058] In the following explanation, for convenience, the case of the upper plate 110 and the heat sink 210 will be used as an example. The heat sink 210 is connected to the upper plate 110 with a separation interval, and the space formed by this separation interval becomes the refrigerant receiving member 220. Therefore, the upper plate 110, the heat sink 210, and the refrigerant receiving member 220 form an integrated structure. The cooling unit 200a is integrally connected to the upper plate 110 and is located on the upper part of the battery cell stack 101.

[0059] However, the present invention is not limited to those described above. For example, the upper plate 110 of the frame does not necessarily have to be a component of the refrigerant receiving member 220 so as to form the refrigerant receiving member 220. As long as the refrigerant receiving member 220 itself has a shape that can store refrigerant, it is sufficient if it has a shape and structure that connects to the battery cell stack 101 with a heat sink 210 including a through-hole 230, which will be described later.

[0060] Furthermore, the cooling section 200a' includes a heat sink 210 and a refrigerant receiving member 220 for housing the refrigerant. The heat sink 210 is connected to the lower plate 120 with a separation distance between them, and the space formed by this separation distance becomes the refrigerant receiving member 220. Therefore, the lower plate 120, the heat sink 210, and the refrigerant receiving member 220 form an integrated structure.

[0061] In other words, the cooling section 200a' is integrally connected to the lower plate 120 and is located at the bottom of the battery cell stack 101. Similarly, the lower plate 120 of the frame does not necessarily have to form a refrigerant receiving member 220. It is sufficient if the refrigerant receiving member 220 itself has a shape that stores refrigerant, and it is sufficient if it has a shape and structure that connects to the battery cell stack 101 with a heat sink 210 including a through-hole 230, which will be described later. The heat sink 210 has a through-hole 230 formed therein, and a sealing member 240 is attached to the through-hole 230.

[0062] The sealing member 240 is made of a material that melts due to the high-temperature gas or sparks released from the battery cell. In other words, when the battery cell is in a normal state, the sealing member 240 maintains a sealed state of the through-hole 230, but when the temperature rises or ignition occurs, as in the case of the battery cell 103, the sealing member 240 melts and the through-hole 230 opens. Through the opened through-hole 230, the refrigerant from the refrigerant receiving member is directly injected into the battery cell stack 101. This process allows for rapid cooling of the overheated or ignited battery cell, thereby quickly preventing the spread of thermal runaway.

[0063] Since the sealing member 240 is made of a material that melts in response to the high-temperature gas or sparks ejected by the venting of the battery cell as its temperature increases, a thermoplastic polymer resin with a melting point of approximately 200°C or lower may be used. For example, the thermoplastic polymer resin may be polyethylene, polypropylene, or other materials with a melting point of approximately 100°C to 200°C.

[0064] On the other hand, 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 flame in the battery cell from becoming larger or an explosion from occurring due to the injection of the cooling water. Therefore, it is preferable that the additive contained in the cooling water does not contain flammable substances. Alternatively, if the additive contains a flammable substance, the amount of the additive may be sufficient to prevent a secondary explosion in the battery cell and to be used as an antifreeze to prevent the cooling water from freezing.

[0065] On the other hand, the refrigerant receiving member 220 houses the refrigerant inside. More specifically, the cooling unit 200a according to the present invention includes an elastic member 250 that can contract and expand within the internal space of the refrigerant receiving member 220. The elastic member 250 is in the shape of a film and is arranged across the internal space of the refrigerant receiving member 220. When the heat sink 210 includes at least one through-hole 230, it is preferable that the film-shaped elastic member 250 covers at least one of the through-holes 230. Also, the elastic member 250 covers at least a portion of the heat sink 210. As a result, the elastic member 250 can divide the internal space of the refrigerant receiving member 220 into two main parts (upper and lower in the embodiment of Figure 2). That is, it is divided into the space between the heat sink 210 including the through-hole 230 and one surface of the elastic member 250, and the space between the other surface of the elastic member 250 and the inner wall of the refrigerant receiving member 220. In this configuration, the refrigerant is contained within the internal space of the refrigerant receiving member 220, specifically in the space between the heat dissipation plate 210 and the elastic member 250, including the through-hole 230.

[0066] The periphery of the elastic member 250 may be fixed to the periphery of one surface of the refrigerant receiving member 220, the surface that is positioned adjacent to the battery cell stack. In other words, in the embodiment of Figure 2, it may be fixed to the portion where the refrigerant 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 refrigerant receiving member 220. Examples of a method in which the periphery of the elastic member 250 is fixed to the inner wall of the refrigerant receiving member 220 or to the portion that comes into contact with the upper plate 110 and / or the heat sink 210 will be described later with reference to Figures 9 to 11. However, in order for all the refrigerant received inside the elastic member 250 to be supplied to the battery cell stack 101 through the through-hole 230 as the elastic member 250 contracts, as will be described later, it is preferable that the elastic member 250 is located on the side of the inner wall of the refrigerant 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 it is sufficient that the refrigerant can be received in the space between the heat sink 210 and the elastic member 250. The embodiment in Figure 2 shows the case where the maximum amount of refrigerant is contained inside the elastic member 250 and the refrigerant is expanded to its maximum extent.

[0067] The refrigerant receiving member 220 may be a water tank that stores refrigerant internally, or it may have a structure that includes an inlet / outlet (not shown) through which the refrigerant flows in and out. If 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 / outlet. In other words, the inlet / outlet may be located in the space between one surface of the refrigerant receiving member on which the through-hole 230 is located and the elastic member 250, and the refrigerant may flow through the inlet / outlet while the refrigerant is contained in the space between one surface of the refrigerant receiving member on which the through-hole 230 is located and the elastic member 250.

[0068] The high-temperature gas or sparks released from the battery cells 103 as the temperature of the battery cell stack 101 rises cause the sealing member 240 attached to the through-hole 230 of the heat sink 210 to melt. Consequently, 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 through the open opening 255 and the open through-hole 230.

[0069] As shown in Figure 2, the elastic member 250, which has expanded to its maximum extent due to the internal pressure of the refrigerant, gradually contracts as the refrigerant received inside the elastic member 250 escapes, and the pressure exerted by the refrigerant on the elastic member 250 gradually decreases, as shown in Figure 3. Unlike the case shown in Figure 14 relating to the prior art, the pressure from the contraction of the elastic member 250 allows the refrigerant inside the elastic member 250 located within the refrigerant receiving member 220 to be supplied to the battery cell 103 at a faster rate. Furthermore, the refrigerant that was in the space between the elastic member 250 and the heat sink 210 can be supplied to the battery cell 103 without any residue.

[0070] The elastic member 250 has elasticity to allow for contraction and expansion, and is made of a material that is not damaged as much as possible by high-temperature gases or sparks released from the battery cell 103. Furthermore, since the elastic member 250 contains a refrigerant, 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 capable of shrinking and expanding. For example, a polymer resin, rubber, or silicone membrane that is capable of shrinking and expanding and has waterproofing properties may be used. As an example, the elastic member 250 may be in the form of a rubber membrane 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 that can shrink and expand. For example, it may have a double structure in which an elastic material is layered on top of a waterproof material (fireproof cloth, etc.) and compressed. As an example, the elastic member 250 may have a double structure in which a rubber band is layered on top of a fireproof cloth.

[0073] The present invention is not limited to those described above, and various modifications and changes are possible, such as the cooling section 200a located at the top of the battery cell stack 101 and the cooling section 200a' located at the bottom of the battery cell stack 101 being equipped only with a heat sink 210 and not with a refrigerant receiving member 220.

[0074] Figure 4 is a vertical cross-sectional view of a battery module or battery pack according to another embodiment of the present invention, showing a cooling section 200b which is a partially modified version of the cooling section 200a in Figure 2. For a description of the components of the cooling section 200b in Figure 4 that overlap with the cooling section 200a in Figure 2, please refer to the description for Figure 2.

[0075] In the embodiment shown in Figure 4, the partition wall 215 can divide the internal space by crossing the refrigerant receiving member 220 in the vertical direction. The partition wall 215 may be, for example, a plate shape that connects the heat sink 210 and the upper plate and is arranged parallel to the side plate 130 (see Figure 1). In such a case, it can be arranged parallel to the longitudinal direction of each battery cell of the battery cell stack 101.

[0076] The refrigerant receiving member 220 is divided into a plurality of sections arranged in a line laterally with respect to the partition wall 215. Each of the plurality of sections partitioned within the refrigerant receiving member 220 is provided with an elastic member 250, and each of the plurality of elastic members 250 contains refrigerant. This allows the refrigerant to be supplied in several portions when the temperature of the battery cell 103 rises or when ignition occurs. Further description of the elastic members 250 is similar to the description above in Figures 2 and 3.

[0077] The number of partition walls 215 is not limited to those shown in Figure 4; there may be one, multiple partition walls 250a, and various other modifications and changes are possible to suit the environment in which the present invention is implemented.

[0078] The shape of the partition wall 215 is sufficient as long as it can separate and partition the internal space of the refrigerant receiving member 220, and does not necessarily have to be a flat planar shape; various deformations and modifications are possible. Figure 5 shows a plan view of an embodiment of the heat sink 210 that can be applied to the cooling section of Figures 2 to 4. Figure 5(a) shows the heat sink 210 with a through-hole 230 formed therein.

[0079] The heat sink 210 has circular through-holes 230 arranged on its surface so as to be spaced at regular intervals along the horizontal and vertical directions.

[0080] In the event of any battery cell ignition, a through-hole must be formed in a location that allows cooling water to be supplied to the ignited battery cell. In other words, it is preferable that at least one through-hole be provided for each battery cell so that cooling water can be supplied to all of them. Therefore, the number and spacing of the through-holes may be adjusted according to the number and size of the battery cells.

[0081] Figures 5(b) and 5(c) are plan views of an embodiment in which the heat sink 210 of Figure 5(a) has been partially modified.

[0082] Referring to Figures 5(b) and 5(c), the shapes of the through-holes 230' and 230″ formed in the heat sink 210 differ from the shape of the through-hole 230 in Figure 5.

[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-holes 230' are formed at an angle so that one through-hole can cover two or more battery cells, and the through-holes 230'' are formed perpendicular to the longitudinal direction L of the battery cells so that two or more battery cells can be covered.

[0084] When a through-hole of this form is formed, if the sealing member melts due to overheating and explosion of any one of the battery cells, the through-hole becomes larger, allowing cooling water to be applied to the surface of a battery cell that is adjacent to the overheated and exploded battery cell but has not overheated or exploded. Therefore, by lowering the temperature of the battery cell that has not overheated or exploded, thermal runaway can be prevented.

[0085] Figure 6 is a magnified view of a portion of Figure 2. Figure 6 shows a magnified view of the portion labeled "A" in Figure 2. A space may form between the battery cell stack 101 and the heat sink 210, and variations may occur in the distance between each individual battery cell and the heat sink 210. This space formed between the battery cell stack 101 and the heat sink 210 reduces the heat dissipation efficiency of the battery module and / or battery pack, which expels heat to the outside.

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

[0087] The heat transfer material 390 widens the thermal connection point between the battery cell stack 101 and the heat sink, allowing the thermal energy generated in the battery cell stack 101 to be quickly dissipated.

[0088] However, if the heat energy released from the battery cell does not directly come into contact with the sealing member due to the heat transfer material 390, the sealing member may not reach its melting temperature. Therefore, the addition of the heat transfer material can be omitted.

[0089] Alternatively, the heat transfer material may not be formed in the lower part of the heat sink's penetration opening, but may be added only to other parts. In this case, even with the addition of the heat transfer material, the thermal energy of the vented battery cell is not lost and can be directly transferred to the sealing member, causing the sealing member to melt and supply coolant to the vented battery cell.

[0090] On the other hand, a sealing member 240 is attached to the through-hole 230 that penetrates the heat sink 210. For example, the sealing member 240 fills the through-hole 230 and includes an extension 241 that further extends outward from around the through-hole 230 on the inner surface 211 and outer surface 212 of the heat sink.

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

[0092] Figure 7 is a magnified vertical cross-sectional view of a battery module or battery pack in which a sealing member is attached to a heat sink with grooves formed in it.

[0093] Referring to Figure 7, a refrigerant receiving member 320 is formed between the upper plate 110 and the 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 on the inner surface 311 and the outer surface 312 of the heat sink where the extension 341 is formed.

[0095] Since a portion of the sealing member constituting the extension 341 is inserted into the groove 314 to form the insertion portion 345, it is possible to more effectively prevent the sealing member from being removed by the water pressure of the cooling water and the through-hole from opening.

[0096] To manufacture the sealing member including the extension portion in this manner, an insert injection molding method may be used, in which a resin for sealing members is injected into a heat sink plate with grooves formed therein. Alternatively, the portion of the sealing member that passes through the through-hole may be formed by preparing a central part of the sealing member having a shape and size corresponding to the shape and size of the through-hole, and then adding a separate member to the central part of the sealing member to form the extension portion. In this case, the method of joining the central part of the sealing member and the separately added extension portion is not limited to bonding with an adhesive substance, screw fastening, interference fit, etc. Furthermore, the central part of the sealing member may be made of a thermoplastic polymer resin that melts at high temperatures, while the material of the separately added extension portion may be made of a material that does not melt at high temperatures.

[0097] Figure 8 is a vertical cross-sectional view of a heat sink with grooves formed on it and a sealing member attached.

[0098] Referring to Figure 8, sealing members 440, 540, and 640 are attached to the heat sinks 410, 510, and 610, respectively.

[0099] Each of the heat sinks 410, 510, and 610 has grooves 414, 514, and 614 formed in the portion that contacts the extension, and insertion portions 445, 545, and 645 are formed inside the grooves 414, 514, and 614.

[0100] In the heat sinks 410, 510, and 610, the vertical cross-sections of the portions in which grooves 414, 514, and 614 are formed may be formed in one or more shapes selected from the group consisting of polygons including triangles and trapezoids, semicircles, and semi-ellipses, or these may be formed in combination.

[0101] Referring to Figure 8(c), the thickness of the central part 641 of the sealing member 640 is formed to be thinner than the thickness of the central part of the sealing member 410 and the central part of the sealing member 510. When the thickness of the part that seals the through-hole is formed to be relatively thin in this way, the time until the sealing member melts and the through-hole opens can be shortened, so that the refrigerant can be supplied to the battery cell quickly.

[0102] Furthermore, the heat sink can constitute a refrigerant receiving member that connects to the upper and lower plates of the frame, and the heat sink can constitute one surface that faces the surface that connects to the upper and lower plates.

[0103] The following describes an example in which the periphery of the elastic member 250 is fixed to the upper plate 110, the heat sink 210, and / or the refrigerant receiving member 220.

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

[0105] A refrigerant receiving member 220 is formed between the upper plate 110 and the heat sink 210 of the battery module or battery pack. An elastic member 250 is also positioned to divide the internal space of the refrigerant receiving member 220 into two large sections. In this case, as described above in Figure 2, the periphery of the elastic member 250 may be fixed to the inner wall of the refrigerant receiving member 220 or to the part that abuts the upper plate 110 and / or the heat sink 210. In Figure 9, the periphery of the elastic member 250 is denoted as B. Since Figure 9 is a schematic representation of a plan view, when viewing the battery module or battery pack three-dimensionally (in 3D) in this invention, the explanation of the periphery B of the elastic member 250 in Figures 9 to 11 can be applied to the front / rear and left / right peripheries of the battery module or battery pack.

[0106] Figure 10 is a conceptual diagram showing an example of a method for fixing the periphery of the elastic member shown in Figure 9, specifically when seaming is performed.

[0107] For example, with the edge of the elastic member 250 interposed between the edge of the upper plate 110 and the edge of the heat sink 210, the edges of the upper plate 110, the heat sink 210, and the elastic member 250 can all be seamed. In other words, the edges can be bent, overlapped, and pressed together during the seaming process. The form and structure of the seamed edges of the upper plate 110, the heat sink 210, and the elastic member 250 are not limited to Figure 10 and can be modified and applied in various ways.

[0108] Figure 11 is a conceptual diagram showing a combination of embossing and mechanical fastening as another example of a method for fixing the periphery of the elastic member shown in Figure 9.

[0109] For example, first, the edges of the upper plate 110 and the heat sink 210 are embossed to create a textured surface. The roughness of the edges of the upper plate 110 and the heat sink 210 is increased by the embossing to prevent the elastic member 250 from slipping. After temporarily fixing the edge of the elastic member 250 between the embossed edges of the upper plate 110 and the heat sink 210, the edges of the upper plate 110, the heat sink 210, and the elastic member 250 can all be mechanically fastened, for example, with rivets / bolts. The form and structure of the embossed edges of the upper plate 110 and the heat sink 210 are not limited to Figure 11 and can be modified and applied in various ways.

[0110] On the other hand, with respect to the method of fixing the periphery of the elastic member, the present invention is not limited to those described above in Figures 9 to 11, and various other processing methods can be modified and applied.

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

[0112] The above description has focused on a battery module or battery pack containing a single battery cell stack 101 and a cooling unit included therein, with reference to the drawings. However, the cooling unit according to the embodiment of the present invention can also be applied in the same manner to a battery pack containing multiple battery cell stacks 101 (cell module assemblies).

[0113] The case in which multiple battery cell stacks 101 (cell module assemblies) are stacked to form a battery pack will be described with reference to Figures 12 and 13. Figure 12 schematically shows a battery pack 100' according to one embodiment of the present invention in which multiple battery cell stacks 101 are housed. Figure 13 is a vertical cross-sectional view of the battery pack according to one embodiment of the present invention shown in Figure 12, showing a case in which a cooling unit 200 is included on top of the multiple battery cell stacks 101 of Figure 12. The battery pack 100' in Figures 12 and 13 shows a case in which one cooling unit 200 is placed on top of the multiple battery cell stacks 101. The cooling unit described in Figures 1 to 11 can be applied in the same manner to the battery pack 100' in which multiple battery cell stacks 101 are stacked.

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

[0115] The frame includes an upper plate 110 positioned above the multiple battery cell stacks 101, a lower plate 120 positioned below the multiple battery cell stacks 101, and side plates (not shown) positioned between the upper plate 110 and the lower plate 120 and on both sides of the multiple battery cell stacks 101. Additionally, a crossbeam 140 may be included between the multiple battery cell stacks 101. The configuration of the frame, including the upper plate 110, the lower plate 120, and the side plates, is not limited to the structure shown in Figures 12 and 13, and can be modified and implemented in various ways to suit the environment in which the present invention is embodied.

[0116] For reference, in Figure 13, the upper plate 110 and lower plate 120 refer to the upper plate and lower plate of the frame, respectively, and for convenience, they are abbreviated as upper plate 110 and lower plate 120. These must be understood as separate concepts from the upper plate and lower plate of the refrigerant receiving member 220, which are based on the refrigerant receiving member 220.

[0117] In Figure 13, the cooling unit 200 includes a refrigerant receiving member 220 that contains a refrigerant. One surface of the refrigerant receiving member 220 is positioned on at least one surface of the plurality of battery cell stacks 101. The other surface of the refrigerant receiving member 220 facing the other surface may be the upper plate 110 of the frame. In other words, if the refrigerant receiving member 220 is provided on top of the plurality of battery cell stacks 101, the upper plate of the refrigerant 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 with a sealing member 240.

[0118] On the other hand, while the refrigerant receiving member 220 of the battery pack 100' in Figure 13 is arranged on top of multiple battery cell stacks 101, the refrigerant receiving member 220a of the battery module or battery pack 100 in Figure 2 is arranged on top of a single battery cell stack 101. However, the detailed components of the refrigerant receiving member 220 in Figure 13 are identical to the detailed components of the refrigerant receiving member 220a of the battery module or battery pack 100 in Figure 2.

[0119] Therefore, the description of the detailed components of the refrigerant receiving member 220 in Figure 13 overlaps with the description of the detailed components of the refrigerant receiving member 220a of the battery module or battery pack 100 in Figure 2. For other descriptions, please refer to those described in Figures 1 to 11. Also, the descriptions of the parts labeled A and B in Figure 13 overlap with the parts described in Figures 6 and 9 to 11, respectively. For those parts, please refer to those described in those sections.

[0120] Furthermore, while Figure 13 shows a case where the cooling unit 200 is placed on top of multiple battery cell stacks 101, various modifications and changes are possible, such as the cooling unit 200 being placed below the multiple battery cell stacks 101. Of course, as mentioned above in the embodiment of Figure 4, the partition wall 215 can also be applied to the cooling unit 220.

[0121] Thus, when using the battery module and / or battery pack and the cooling unit included therein according to the present invention, even if a battery cell ignites, the battery cell can be rapidly cooled. Furthermore, even if the refrigerant receiving space is arranged at an angle, all of the refrigerant in the refrigerant receiving space can be supplied to the ignited battery cell. This minimizes the increase in volume of the battery module and / or battery pack, while efficiently suppressing the thermal runaway phenomenon of the battery cell.

[0122] A person with ordinary skill in the art to which the present invention belongs will be able to make various applications and modifications within the scope of the present invention based on the above.

[0123] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. Various modifications and improvements made by those skilled in the art using the basic concepts of the present invention as defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0124] 101: Battery cell stack 110: Top 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 multiple battery cells are stacked, A frame for housing the aforementioned battery cell stack, The battery cell stack includes a cooling section, The cooling unit is A refrigerant receiving member including an upper plate and a lower plate, An elastic member disposed in the internal space of the refrigerant receiving member, The refrigerant receiving member includes a sealing member that seals at least one through-hole formed in the lower plate and is meltable by the temperature rise of the battery cell, A battery pack in which 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 a result of the refrigerant being received.

2. The battery pack according to claim 1, wherein the elastic member is in the shape of a membrane and covers the lower plate of the refrigerant receiving member which includes 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 in the battery cells, the elastic member pressurizes the refrigerant and supplies the refrigerant to the battery cell stack.

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

5. The battery pack according to claim 2, wherein the periphery of the membrane-shaped elastic member is fixed to the periphery of the lower plate of the refrigerant receiving member or in the vicinity of the periphery of the lower plate of the refrigerant receiving member.

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

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

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

9. The battery pack according to claim 1, wherein the refrigerant receiving member has a structure integrated with the frame, and the upper plate of the refrigerant receiving member constitutes a part of the frame.

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

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

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

13. The refrigerant receiving member includes at least one partition wall positioned within the internal space to divide it into multiple regions. The at least one partition wall is positioned perpendicular to one surface of the refrigerant receiving member and in the longitudinal direction of the battery cell, The battery pack according to claim 1, wherein the elastic members are individually provided across each of the plurality of areas.

14. 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 melting point of the elastic member is higher than the melting point of the sealing member.

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

17. 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 that can shrink and expand.

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

19. The aforementioned frame is The upper plate of the frame, which is positioned on the upper side of the aforementioned battery cell stack, The lower plate of the frame, which is positioned on the lower side of the battery cell stack, Between the upper plate and the lower plate, there is a side plate of a frame positioned on the side of the battery cell stack, The battery pack according to claim 1, wherein the lower plate of the refrigerant receiving member is arranged at a predetermined distance from the frame to form the refrigerant receiving member.

20. The battery cell stack comprises a plurality of the aforementioned battery cell stacks, The battery pack according to claim 1, wherein the cooling unit is arranged on a plurality of battery cell stacks.

Images