Battery pack and device including the same

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 pack frame that houses the battery cell stack, a cooling member located on an upper side of the battery cell stack and containing cooling water, and a foam pad located between the battery cell stack and the cooling member, wherein a lower plate of the cooling member is formed with at least one weak portion that breaks or melts at a predetermined temperature or pressure or above, and when the weak portion of the cooling member is opened, a movement path of the cooling water discharged toward the battery cell stack is guided by the foam pad.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2022 - 0020767, filed on February 17, 2022, and all the contents disclosed in the literature of the Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery pack and a device including the same, and more specifically, to a battery pack and a device including the same for preventing a chain thermal runaway phenomenon.

Background Art

[0003] In modern society, as the use of portable devices such as mobile phones, notebook computers, video cameras, and digital cameras has become common, the technological development in the fields related to such mobile devices has become active. In addition, rechargeable secondary batteries are a solution for solving problems such as air pollution in existing gasoline vehicles that use fossil fuels, and are used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug - in hybrid electric vehicles (P - HEVs), etc. Therefore, the need for the development of secondary batteries is increasing.

[0004] Currently commercialized secondary batteries include nickel - cadmium batteries, nickel - metal hydride batteries, nickel - zinc batteries, lithium secondary batteries, etc. Among them, lithium secondary batteries have the advantages of free charge and discharge, low self - discharge rate, and high energy density, and are the most widely noted.

[0005] On the one hand, in the case of a secondary battery used in a small device, mainly 2-3 battery cells are used. However, in the case of a secondary battery used in a medium or large device such as an automobile, a medium or large battery module in which a plurality of battery cells are electrically connected is used. Since the medium or large battery module is preferably manufactured with the smallest possible size and weight, prismatic batteries, pouch-type batteries, etc. that can be stacked with a high degree of integration and have a small weight compared to their capacity are mainly used as the battery cells of the medium or large battery module.

[0006] On the other hand, the battery cells mounted on the battery module generate a large amount of heat during the charge and discharge process. When the temperature becomes higher than the appropriate temperature due to reasons such as overcharging, the performance may deteriorate. In the case of excessive temperature rise, there is a risk of explosion or ignition. When an ignition phenomenon occurs inside the battery module, high-temperature heat, gas, or flame may be released to the outside of the battery module. At this time, heat, gas, sparks, or flame released from one battery module may be transmitted to other adjacent battery modules with a narrow interval in the battery pack, thereby causing a continuous thermal runaway phenomenon in the battery pack.

[0007] In order to prevent such a thermal runaway phenomenon, recently, a method of suppressing the fire by injecting cooling water when a fire occurs in the battery module has been developed. However, if the injected cooling water does not concentrate on the thermal runaway occurrence position, there is a problem that the fire suppression effect is slightly reduced compared to the amount of the injected cooling water.

[0008] Therefore, at present, there is a need for a new structure that can quickly suppress the thermal runaway phenomenon by injecting cooling water at the right time and place when an internal fire occurs in the battery module or battery pack, and the injected cooling water can be efficiently utilized.

Summary of the Invention

Problems to be Solved by the Invention

[0009] The problem to be solved by the present invention is to provide a battery pack and a device including the same that can inject cooling water at an appropriate time and place during internal ignition and concentrate the injected cooling water around the fire occurrence site.

[0010] However, the problems to be solved by the embodiments of the present invention are not limited to the above-described problems, and can be variously extended within the scope of the technical idea included in the present invention.

Means for Solving the Problems

[0011] A battery pack according to an embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a pack frame that houses the battery cell stack, a cooling member located above the battery cell stack and containing cooling water, and a foam pad located between the battery cell stack and the cooling member. At least one fragile portion that breaks or melts at a predetermined temperature or pressure or higher is formed on the lower plate of the cooling member. When the fragile portion of the cooling member is opened, the movement path of the cooling water discharged toward the battery cell stack is guided by the foam pad.

[0012] The foam pad includes at least one opening, and the opening of the foam pad can correspond to the fragile portion.

[0013] A part of the cooling water discharged toward the battery cell stack is absorbed by the foam pad.

[0014] There are a plurality of the battery cell stacks, and the foam pad can correspond to all of the respective battery cell stacks.

[0015] A plurality of openings are formed in the lower plate, the openings are closed by a sealing member, and the fragile portion may be a portion of the lower plate where the openings closed by the sealing member are located.

[0016] The cooling member includes a cooling tube that provides a flow path for cooling water and a cooling hose attached to the cooling tube. A plurality of openings are formed in the lower plate, and the cooling hose is positioned to correspond to the openings. The vulnerable part may be a part of the lower plate where the opening closed by the cooling hose is located.

[0017] The lower plate and the cooling tube are connected by a strap-shaped fixing member.

[0018] The lower plate includes a first part where the vulnerable part is formed and a second part where the vulnerable part is not formed, and the thickness value of the first part is smaller than the thickness value of the second part.

[0019] The thickness value of the first part may be half or less of the thickness value of the second part.

[0020] The lower plate is formed by joining a first layer and a second layer having different thicknesses from each other. The thickness of the first part corresponds to the thickness of the first layer, and the thickness of the second part can correspond to the thicknesses of the first layer and the second layer.

[0021] The upper plate includes a bent part, and the peak of the bent part can correspond to the first part, and the valley of the bent part can correspond to the second part.

[0022] The cooling member further includes an in / out port for injecting cooling water into the internal space of the cooling member. The in / out port is connected to an external heat exchanger, and the cooling water of the cooling member can circulate through the in / out port.

[0023] The upper plate of the cooling member may be the upper surface of the pack frame.

[0024] A device according to another embodiment of the present invention can include the battery pack described above.

Advantages of the Invention

[0025] According to the embodiment, cooling water is introduced into the battery cell where thermal runaway has occurred from the cooling member inside the battery pack, and the cooling water introduced by the foam pad is concentrated around the fire site, so that the internal fire is quickly suppressed, and the continuous thermal runaway phenomenon can be prevented.

[0026] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

Brief Description of the Drawings

[0027]

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Mode for Carrying Out the Invention

[0028] Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement them. The present invention can be realized in various different forms other than those described below, and the scope of the present invention is not limited by the embodiments described here.

[0029] Parts unnecessary for explanation are omitted in order to clearly explain the present invention, and the same reference numerals are given to the same or similar components throughout the specification.

[0030] In addition, the sizes and thicknesses of the respective components shown in the drawings are arbitrarily enlarged or reduced for the sake of convenience of explanation, so it is obvious that the content of the present invention is not limited to what is shown in the drawings. In the following drawings, the thicknesses of the respective layers are enlarged to clearly represent various layers and regions. And in the following drawings, for the sake of convenience of explanation, the thicknesses of some layers and regions are exaggeratedly shown.

[0031] In addition, when explaining that a part such as a layer, film, region, or plate is "on" another part, this should be interpreted to include not only the case where the part such as the layer, film, region, or plate is directly "above" the other part, but also the case where there are other parts in between. Conversely, when explaining that the part such as the layer, film, region, or plate is "directly above" the other part, it can be meant that there are no other parts in between. Note that being "on" the reference part means being located above or below the reference part, and does not necessarily mean being "on" in the direction opposite to gravity. On the other hand, similar to explaining being "on" another part, explaining being "below" another part will also be understood with reference to the above-described content.

[0032] Furthermore, since the upper surface / lower surface of a specific member can be differently determined depending on the reference direction, throughout the specification, "upper surface" or "lower surface" is defined to mean the two surfaces facing each other on the z-axis in the member.

[0033] In addition, throughout the specification, when a certain part "includes" a certain component, this means that, unless otherwise stated to the contrary, it does not exclude other components but can further include other components.

[0034] Furthermore, throughout the specification, when referring to "in a plane", this means when looking at the part from above, and when referring to "in a cross-section", this means when looking at the cross-section obtained by vertically cutting the part from the side.

[0035] Hereinafter, a battery pack according to an embodiment of the present invention will be described.

[0036] Generally, a conventional battery pack has a double-assembly structure in which a battery cell laminate and various components connected thereto are assembled to form a battery module, and a plurality of battery modules are further housed in the battery pack.

[0037] At this time, since the battery module includes a module frame that forms its outer surface, etc., the conventional battery cell is doubly protected by the module frame of the battery module and the pack frame of the battery pack. However, such a double-assembly structure not only increases the manufacturing cost and manufacturing process of the battery pack, but also has the demerit that when a defect occurs in some battery cells, the reassembly property deteriorates. Also, when a cooling member or the like exists outside the battery module, there is a problem that the heat transfer path between the battery cell and the cooling member becomes somewhat complicated.

[0038] Therefore, the battery cell laminate of the present embodiment can be provided in a structure that is not sealed by a module frame and can be directly coupled to the pack frame of the battery pack. As a result, the structure of the battery pack becomes simpler, and advantages in terms of manufacturing cost and manufacturing process can be obtained, and the effect of achieving weight reduction of the battery pack can be achieved. Also, thereby, the battery cell laminate can be positioned closer to the cooling member in the pack frame, and heat dissipation by the cooling member can be more easily achieved.

[0039] Therefore, the "battery pack" described below has a structure including a battery cell laminate and a frame that houses it, and thus is not limited to including a sealed battery module as in the prior art, and can broadly refer to a structure in which a battery cell laminate and various components connected thereto are assembled. From such a viewpoint, the battery pack of the present embodiment may be referred to as a battery module as needed.

[0040] Figures 1 and 2 are exploded perspective views showing a battery pack according to an embodiment of the present invention. Figure 3 is a perspective view of a cell block included in the battery pack according to Figure 1. Figure 4 is a view showing a lower plate of a cooling member included in the battery pack according to Figure 1. Figures 5 and 6 are diagrams for explaining changes in the cooling member and the foam pad before and after a thermal runaway phenomenon. Figure 7 is a diagram for explaining changes after a thermal runaway phenomenon when no foam pad is provided in the battery pack of Figure 1.

[0041] Referring to FIGS. 1 to 3, a battery pack 1000 according to an embodiment of the present invention may include at least one cell block 100, a pack frame 200 that houses the cell block 100, a resin layer 300 formed on an inner surface of the pack frame 200, an end plate 400 that closes an open surface of the pack frame 200, a cooling member 500 disposed between the pack frame 200 and the cell block 100, and a foam pad 700 positioned between the cooling member 500 and the cell block 100. However, the components included in the battery pack 1000 are not limited thereto, and depending on the design, the battery pack 1000 may be provided in a state where some of the above-described components are omitted, or may be provided in a state where other components not mentioned are added.

[0042] The battery pack 1000 according to the present embodiment may include a cell block 100 that is not sealed by a frame or the like. The cell block 100 may be similar to a structure in which a module frame is omitted in a conventional battery module, and thus may be referred to as a battery module having an "open structure" or a "module-less structure".

[0043] The cell block 100 can include a cell stack 120 in which a plurality of battery cells 110 are stacked along one direction, side plates 130 positioned at both ends in the stacking direction of the cell stack 120, a holding strap 140 surrounding the side plates 130 and the cell stack 120 to fix its form, and a bus bar frame 150 covering the front and rear surfaces of the cell stack 120.

[0044] Each battery cell 110 can include an electrode assembly, a cell case, and an electrode lead protruding from the electrode assembly. The battery cell 110 is provided in a pouch type or a square type that can maximize the number stacked per unit area. On the other hand, in FIGS. 1 to 3, it is shown that the positive electrode lead and the negative electrode lead of the battery cell 110 protrude in opposite directions, but this is not necessarily the case, and the electrode leads of the battery cell 110 can also protrude in the same direction.

[0045] The cell stack 120 may be one in which a plurality of electrically connected battery cells 110 are stacked along one direction. The direction in which the plurality of battery cells 110 are stacked (hereinafter referred to as the "stacking direction") may be the y-axis direction (or it may be the -y-axis direction, and hereinafter, the expression "axial direction" can be interpreted to include all + / - directions) as shown in FIGS. 1 to 3.

[0046] On the other hand, by arranging the battery cells 110 along one direction, the electrode leads of the battery cells 110 can be located on one surface of the cell stack 120, or on one surface and the other surface facing the one surface. In this way, the surface on which the electrode leads are located in the cell stack 120 may be referred to as the front surface or the rear surface of the cell stack 120. In FIGS. 1 to 3, the front surface and the rear surface of the cell stack 120 are shown as two surfaces facing each other on the x-axis. Also, the surface on which the outermost battery cell 110 is located in the cell stack 120 may be referred to as the side surface of the cell stack 120, and the side surfaces of the cell stack 120 are shown as two surfaces facing each other on the y-axis.

[0047] The side plate 130 is provided to maintain the overall shape of the battery cell stack 120. The side plate 130 is a plate-shaped member and can complement the rigidity of the cell block 100 instead of the module frame. The side plates 130 are disposed at both ends in the stacking direction of the battery cell stack 120 and can contact the outermost battery cells 110 on both sides of the battery cell stack 120.

[0048] The side plate 130 can be manufactured from various materials and provided by various manufacturing methods. As an example, the side plate 130 may be a plastic material manufactured by injection molding. As another example, the side plate 130 is manufactured from a leaf spring material. As yet another example, the side plate 130 is manufactured from a material having elasticity such that its shape can be partially deformed in response to the volume change of the battery cell stack 120 due to swelling.

[0049] The holding strap 140 may be for fixing the positions and forms of the side plates 130 at both side ends of the battery cell stack 120. The holding strap 140 may be a member having a length and a width. Specifically, the battery cell stack 120 can be positioned between two side plates 130 that contact the outermost battery cells 110, and the holding strap 140 can connect the two side plates 130 across the battery cell stack 120. Thereby, the holding strap 140 prevents the distance between the two side plates 130 from increasing beyond a certain range, whereby the overall shape of the cell block 100 can be maintained within a certain range.

[0050] The holding strap 140 can have hooks at both ends in its longitudinal direction for stable connection with the side plate 130. The hooks are formed by bending both ends in the longitudinal direction of the holding strap 140. On the other hand, locking grooves are formed in the side plate 130 at positions corresponding to the hooks, and the holding strap 140 and the side plate 130 can be stably connected by the connection between the hooks and the locking grooves.

[0051] The holding strap 140 can be provided with various materials or by various manufacturing methods. As an example, the holding strap 140 is manufactured with an elastic material, whereby the volume change of the battery cell laminate 120 due to swelling can be allowed within a certain range.

[0052] On the other hand, the holding strap 140 is for fixing the relative position between the side plate 130 and the battery cell laminate 120, and as long as its purpose as a "fixing member" is achieved, it can also be provided in a form different from that shown in the figure. For example, the fixing member is provided in the form of a long bolt that can cross between the two side plates 130, that is, a long bolt. The side plate 130 is provided with a groove into which the long bolt can be inserted, and the long bolt can fix the relative position of the two side plates 130 by simultaneously connecting to the two side plates 130 through the groove. The long bolt is provided at the periphery of the side plate 130, preferably at a position close to the apex of the side plate 130. Depending on the design, it is also possible to replace the holding strap 140 with the above-mentioned long bolt, but it is also possible that both the holding strap 140 and the long bolt are provided in the cell block.

[0053] The bus bar frame 150 may be located on one surface of the battery cell laminate 120 to cover one surface of the battery cell laminate 120 and at the same time guide the connection between the battery cell laminate 120 and an external device. The bus bar frame 150 can be located on the front or rear surface of the battery cell laminate 120. A bus bar is mounted on the bus bar frame 150, whereby the electrode leads of the battery cell laminate 120 are connected to the bus bar, and thus the battery cell laminate 120 is electrically connected to an external device.

[0054] The bus bar frame 150 can include a material that is electrically insulating. The bus bar frame 150 can limit contact of other portions of the battery cell 110 except for the portion where the bus bar is joined to the electrode lead, and can prevent an electrical short circuit from occurring.

[0055] The pack frame 200 may be for protecting the cell block 100 and electrical components connected thereto from external physical impacts. The pack frame 200 can house the cell block 100 and electrical components connected thereto in the internal space of the pack frame 200. Here, the pack frame 200 includes an inner surface and an outer surface, and the internal space of the pack frame 200 is defined by the inner surface.

[0056] The pack frame 200 is provided in a hollow form that is open along one direction. For example, as shown in FIG. 1, a plurality of cell blocks 100 are continuously positioned along the stacking direction of the battery cells 110, and the pack frame 200 can have a hollow form that is open along the above-described stacking direction.

[0057] The pack frame 200 can include a lower frame 210 and an upper frame 220. Here, the lower frame 210 is provided in a plate shape, and the upper frame 220 is provided in a U shape. At least one cell block 100 is arranged on the plate-shaped lower frame 210, and the U-shaped upper frame 220 is provided so as to surround the upper surface of the cell block 100 and two surfaces on the x-axis. Also, either one of the upper frame 220 and the lower frame 210 may be formed so as to surround two surfaces on the y-axis of the battery pack 1000, and in this case, the end plate 400 can be omitted. However, the shape of the pack frame 200 shown in FIG. 1 is merely exemplary, and the pack frame 200 may be provided as a monoframe, or may be provided in a form different from the above-described one, such as the lower frame 210 being provided in a U shape and the upper frame 220 being provided in a plate shape.

[0058] The pack frame 200 can include a portion with high thermal conductivity in order to quickly release the heat generated from the internal space to the outside. For example, at least a part of the pack frame 200 can be manufactured from a metal with high thermal conductivity, and examples thereof may include aluminum, gold, silver, copper, platinum, or an alloy containing these. Also, the pack frame 200 can be partially electrically insulating, and an insulating film can be provided at positions where insulation is required, or an insulating coating can be applied. A portion of the pack frame 200 where the insulating film or the insulating coating is applied may be referred to as an insulating portion.

[0059] A resin layer 300 is provided between the cell block 100 and the inner surface of the pack frame 200. The resin layer 300 is provided between the bottom surface of the cell block 100 and the lower frame 210. The resin layer 300 is provided between the upper surface of the cell block 100 and the upper frame 220. Also, the resin layer 300 may be provided between the cooling member 500, which will be described later, and the upper frame 220.

[0060] The resin layer 300 may be formed by injecting resin between the battery cell laminate 120 and one side surface of the inner surface of the pack frame 200. However, not necessarily limited thereto, the resin layer 300 may be a member provided in a plate shape.

[0061] The resin layer 300 is manufactured from various substances, and the functions of the resin layer 300 vary depending on the substance. For example, the resin layer 300 may be formed of an insulating substance, and electron transfer between the cell block 100 and the pack frame 200 can be prevented through the insulating resin layer 300. As another example, the resin layer 300 is formed of a heat-conductive substance. The resin layer 300 manufactured from a heat-conductive substance allows heat generated from the battery cell 110 to be transferred to the pack frame 200 so that the heat can be released / transferred to the outside. As yet another example, the resin layer 300 can contain an adhesive substance, whereby the cell block 100 and the pack frame 200 can be fixed to each other. As a specific example, the resin layer 300 is provided to contain at least one of a silicone-based material, a urethane-based material, and an acrylic-based material.

[0062] The end plate 400 may be for protecting the cell block 100 and the electrical components connected thereto from external physical impacts by sealing the open surface of the pack frame 200. Each corner of the end plate 400 can be joined to the corresponding corner of the pack frame 200 by a method such as welding. Two end plates 400 are provided to seal the two open surfaces of the pack frame 200 and are manufactured from a metallic substance having a predetermined strength.

[0063] An opening 410 for exposing the inlet / outlet port 530 of the cooling member 500 described later is formed in the end plate 400, and a connector 420 for LV (Low voltage) connection or HV (High voltage) connection to an external device is mounted.

[0064] The cooling member 500 is provided to lower the internal temperature of a battery module or a battery pack including a battery cell. The cooling member 500 may be a water-cooled cooling member 500 into which a refrigerant or cooling water is injected. By providing the cooling member 500 in a water-cooled manner, the cooling efficiency of the cooling member 500 is maintained uniformly, and the battery cells in the battery module or the battery pack are cooled evenly. At this time, as the cooling water used for the cooling member 500, one of known ones or a mixture thereof can be used, and any of the known ones may be used as long as it can release the heat of the battery cell by moving along the flow path inside the cooling member 500.

[0065] The cooling member 500 is disposed on one surface of the battery cell stack in order to release the heat of the battery cell. The cooling member 500 is disposed parallel to the stacking direction of the battery cell stack so as to be close to a plurality of battery cells of the battery cell stack. Specifically, the cooling member 500 can be located above the battery cell stack (in the +z-axis direction in FIG. 1). However, it is not necessarily limited thereto, and depending on the design, the cooling member 500 may be located below the battery cell stack (in the -z-axis upward direction) or on the side portion (in the + / -y-axis upward direction).

[0066] The cooling member 500 may include an upper plate 510 and a lower plate 520 that form the outer shape of the cooling member 500, and an inlet / outlet port 530 for injecting cooling water into the cooling member 500. The cooling member 500 is formed by joining the peripheries of the upper plate 510 and the lower plate 520. Cooling water can be built in or circulated between the upper plate 510 and the lower plate 520 joined by the cooling member 500.

[0067] The upper plate 510 and the lower plate 520 are provided in a plate shape. Also, the upper plate 510 or the lower plate 520 is provided in a plate shape and its central portion is formed to be sunken or indented and have a step with the peripheral portion. Specifically, the upper plate 510 or the lower plate 520 can have a concave shape based on the cross-section in the width direction. This may be such that the upper plate 510 or the lower plate 520 forms an internal space by a step in order to accommodate cooling water. Here, the width direction of the upper plate 510 or the lower plate 520 may be a direction parallel to the short side of the upper plate 510 or the lower plate 520.

[0068] In order to improve the overall heat dissipation performance of the cooling member 500, the upper plate 510 or the lower plate 520 of the cooling member 500 is provided with a material having a high thermal conductivity. The upper plate 510 and the lower plate 520 forming the outer shape of the cooling member 500 can be manufactured with a highly rigid metal, and specific examples thereof include aluminum, gold, silver, copper, platinum, or an alloy containing these.

[0069] On the other hand, in the drawings of this specification, although the upper plate 510 is shown as a separate configuration from the pack frame 200, for the purpose of weight reduction or improvement of the thermal conductivity of the battery pack 1000, the upper plate 510 may be replaced with the upper surface of the pack frame 200, and the cooling member 500 may be provided in a structure integrated with the pack frame 200.

[0070] Cooling water is supplied through the inlet ports 532 located side by side and discharged to the outlet port 534. The cooling water in the cooling member 500 can be connected to an external heat exchanger connected to the inlet / outlet port 530 in order to maintain the constancy of its temperature and designed to circulate continuously. The inlet port 532 and the outlet port 534 can be located side by side in parallel on one end side of the cooling member 500. This may be for simplifying the design regarding the inflow and discharge of the cooling water supplied from outside the battery pack 1000. Also, this may be for minimizing the temperature difference between the periphery of the inlet port 532 and the periphery of the outlet port 534. Specifically, the cooling water flowing into the inlet port 532 can have the lowest temperature, and the cooling water discharged to the outlet port 534 can have the highest temperature. Therefore, when the inlet / outlet ports 530 are arranged adjacent to each other, heat exchange occurs between them, and the temperature deviation of the entire cooling water flowing through the internal space of the cooling member can be minimized. Therefore, by arranging the inlet / outlet ports 530 side by side, the cooling member 500 can have a generally uniform heat dissipation performance.

[0071] On the other hand, at least one vulnerable part 600 is formed in the cooling member 500 of this embodiment.

[0072] When ignition occurs in a battery cell, in order to effectively suppress this, it is effective to inject a liquid such as cooling water into the battery module or the battery pack. Providing a liquid tank inside the battery module or the battery pack may have the problem of increasing the volume of the battery module and the battery pack. Conventionally, a separate water tank is provided outside the battery module and the battery pack, and cooling water or the like is only poured into the battery module or the battery pack through a nozzle or the like extending from the water tank only when ignition of the battery cell is confirmed via a sensor.

[0073] However, the water tank not only has a large volume but also has the problem that the user has to manage it separately. In addition, the conventional water injection system has to be equipped with a separate control unit or communication unit for determining the presence or absence of cooling water injection, etc., and errors must not occur in these operations, and even if it operates normally, it has to go through many judgment processes, so it takes a lot of time. Even after the injection of the cooling water is determined, if the path from the water tank to the battery cells inside the battery module or the battery pack is rather long, it is difficult to quickly supply the cooling water from the water tank to the battery cells, and it has been the current situation that it is difficult for the conventional water injection system to suppress the continuously progressing thermal runaway phenomenon. Therefore, in the present embodiment, a fragile part 600 that melts or breaks at a predetermined temperature or pressure can be formed in the cooling member 500 so that the cooling water can be immediately supplied to the fire location when an internal fire occurs in the battery module or the battery pack.

[0074] The fragile part 600 may refer to a part that melts or breaks at a predetermined temperature or pressure. The fragile part 600 is a configuration for allowing the cooling water to be immediately supplied to the fire location by being opened when an internal fire occurs in the battery pack 1000, and can be provided in various structures.

[0075] For example, referring to FIGS. 4 to 6, the lower plate 520 may include at least one opening 521, and the opening 521 is sealed by a sealing member 529. The sealing member 529 prevents the outflow of the cooling water by sealing the opening 521 before the thermal runaway phenomenon, and by melting or breaking after the thermal runaway phenomenon, allows the cooling water in the cooling member 500 to be injected toward the battery cells 110.

[0076] In the present embodiment, the fragile part 600 may refer to the part of the lower plate 520 where the opening 521 is located. The fragile part 600 may refer to the part of the lower plate 520 where the sealing member 529 is located. The fragile part 600 may refer to the part of the lower plate 520 where the opening 521 sealed by the sealing member 529 is formed.

[0077] The sealing member 529 is made of a material that melts or breaks at a predetermined temperature or pressure. For example, the sealing member 529 is made of a material having a melting point of 300 °C or lower. As a specific example, the sealing member 529 is manufactured to contain polyamide (PA). As another specific example, the sealing member 529 is manufactured to contain a thermoplastic polymer resin having a melting point of 200 °C or lower. Examples of the thermoplastic polymer resin include substances such as high-density polyethylene (HDPE), polyethylene (PE), polypropylene (PP), and polyphenylene oxide (PPO) having a melting point of about 100 °C or higher and 200 °C or lower.

[0078] The sealing member 529 is provided in an I shape. At least a part of both ends of the sealing member 529 can be in surface contact with the upper and lower surfaces of the lower plate 520, whereby the connection between the sealing member 529 and the lower plate 520 can be easily achieved. By design, raised or recessed protrusions or grooves are formed on the contact surfaces where the sealing member 529 contacts the upper and lower surfaces of the lower plate 520. By engaging the protrusions or grooves formed on the sealing member 529 with the grooves or protrusions formed on the lower plate 520, the detachment of the sealing member 529 due to the pressure of the cooling water can be more effectively prevented.

[0079] On the other hand, even if the cooling water is discharged from the cooling member 500 toward the battery cell 110 due to the opening of the fragile part 600, it is difficult to quickly achieve fire suppression unless the cooling water concentrates around the fire site. Therefore, the battery pack 1000 of the present embodiment can include a foam pad 700 that concentrates the cooling water around the fire occurrence site.

[0080] The foam pad 700 can be located between the cooling member 500 and the cell block 100. The foam pad 700 can be located between the cooling member 500 and the battery cell laminate 120.

[0081] The foam pad 700 may be for guiding the flow of the cooling water discharged from the cooling member 500 when the weak part 600 is opened. As shown in FIG. 6, when thermal runaway occurs in the first battery cell 110A, only the weak part 600 around the position where the thermal runaway occurs is opened, and the cooling water discharged through the opened weak part 600 can be concentrated on the first battery cell 110A with its flow restricted by the foam pad 700. However, as shown in FIG. 7, when the foam pad 700 does not exist, the cooling water widely diffuses on the upper surface of the battery cell stack 120, whereby it is difficult to supply a sufficient amount of cooling water to the first battery cell 110A.

[0082] The foam pad 700 may include at least one pad opening 710. The pad opening 710 can correspond to the weak part 600 of the cooling member 500. By the pad opening 710 corresponding to the weak part 600, the cooling water discharged from the weak part 600 can be intensively input into the first battery cell 110A without being obstructed by the foam pad 700.

[0083] The foam pad 700 may be for absorbing a part of the cooling water discharged from the cooling member 500. The foam pad 700 is provided as including a plurality of pores and can absorb fluid through the pores. When the cooling water discharged from the cooling member 500 is absorbed by the foam pad 700, moisture remains around the first battery cell 110A, whereby the fire extinguishing of the first battery cell 110A can be quickly achieved. Further, by moisture remaining on the upper part of the first battery cell 110A, the release of particles or gases that can be induced from the first battery cell 110A can be minimized.

[0084] The foam pad 700 can correspond to the battery cell stack 120 included in the battery pack 1000. When there are a plurality of battery cell stacks 120 included in the battery pack 1000, the foam pad 700 can correspond to the plurality of battery cell stacks 120. At this time, a plurality of foam pads 700 may be provided to correspond to each battery cell stack 120, or one foam pad 700 may be provided to correspond to the plurality of battery cell stacks 120.

[0085] Hereinafter, a battery pack according to another embodiment of the present invention will be described.

[0086] The battery pack of the embodiment described below is the same as the content of the above-described embodiment except that the structure of the cooling member is different. Therefore, in describing this embodiment, the same drawing numbers are assigned to the configurations common to the above-described embodiment, and detailed descriptions thereof are omitted.

[0087] FIG. 8 is a cross-sectional view showing a cooling member included in a battery pack according to another embodiment of the present invention. FIG. 9 is a view showing the connection between the lower plate and the cover film included in the cooling member according to FIG. 8.

[0088] Referring to FIGS. 8 and 9, the cooling member 500 of this embodiment can include a cover film 580. The cover film 580 may be configured to close the opening 521 of the lower plate 520 before the ignition of the battery cell 110 and open the opening 521 when the battery cell 110 ignites. When the cover film 580 is broken by the temperature and pressure due to the ignition of the battery cell, the cooling water inside the cooling member 500 is poured toward the battery cell, thereby suppressing the fire.

[0089] In this embodiment, the vulnerable part 600 may refer to the part of the lower plate 520 where the opening 521 is located. The vulnerable part 600 may refer to the part of the lower plate 520 where the opening 521 closed by the cover film 580 is formed.

[0090] The cover film 580 is made of a material that melts or breaks at a predetermined temperature or pressure. The cover film 580 is made of the same or a similar material as the sealing member 529 of the above-described embodiment.

[0091] The cover film 580 can be disposed between the upper plate 510 and the lower plate 520 and positioned to cover the lower plate 520. The cover film 580 can adhere to the lower plate 520. The outer contour shape of the cover film 580 may be generally similar to or the same as the outer contour shape of the lower plate 520. The specific shape of the cover film 580 may be similar to or the same as the shape of the lower plate 520 excluding the opening 521.

[0092] The cover film 580 preferably has a thickness of a predetermined value or more so as to withstand the gravity due to the weight of the cooling water and the frictional force due to the flow of the cooling water. However, if the cover film 580 is excessively thick, the heat dissipation performance of the cooling member 500 may be reduced, so it needs to be adjusted to an appropriate thickness. The thickness of the cover film 580 is manufactured to be 2 mm or less, or 1.5 mm or less. However, considering the durability of the cover film 580 and the reduction in heat dissipation performance due to the cover film 580, it is preferably manufactured to be 0.5 to 1.0 mm. If the thickness of the cover film 580 is less than 0.5 mm, problems may occur in durability. If the thickness of the cover film 580 is greater than 1.0 mm, the heat dissipation performance of the cooling member 500 may be reduced.

[0093] Since the cover film 580 is disposed in combination with the lower plate 520, cooling water can flow between the upper surface of the cover film 580 and the lower surface of the upper plate 510. Further, even if the cover film 580 is added to the cooling member 500, the inflow and outflow of the cooling water through the inlet / outlet port 530 are not restricted by the cover film 580. Therefore, the cooling water in the cooling member 500 can be designed to be continuously circulated by being connected to an external heat exchanger connected to the inlet / outlet port 530 for the constancy of its temperature.

[0094] On the one hand, when a sealing member 529 or a cover film 580 made of a material with a lower melting point than the lower plate 520 is provided to the cooling member 500, the cooling member 500 can include two materials with different physical properties. Conventionally, since the upper plate 510 and the lower plate 520 of the cooling member 500 were mainly joined by brazing or laser welding, etc., when the cooling member 500 was designed to include two or more materials in this way, one material could be deformed during the welding process, so there were problems that the welding process became difficult or impossible. Also, when using laser welding or the like, a local temperature gradient could be formed in the upper plate 510 or the lower plate 520, and thus there was a problem that at least a part of the upper plate 510 or the lower plate 520 was bent.

[0095] Therefore, the cooling member 500 of this embodiment can be manufactured by a mechanical fastening method in order to minimize such problems. The mechanical fastening method used in the manufacture of this embodiment can minimize damage to the material forming the cooling member 500 by not applying heat or applying heat at a temperature lower than the melting point of the material provided to the cooling member 500.

[0096] As an example of the mechanical fastening method used for the cooling member 500, there is a rivet which is a joining by a fastening member. The cooling member 500 can include a plurality of fastening parts joined via a fastening member such as a rivet, and a fastener into which the fastening member can be inserted is formed on the lower plate 520 or the like. In FIG. 9, the positions of the fasteners formed on the lower plate 520 or the cover film 580 are illustrated as points.

[0097] Another example of the mechanical fastening method used for the cooling member 500 is clinching. Clinching is a deformation joining method of mechanically joining two members by pressing one surface of two laminated plate-like members using a punch or the like to deform its shape. Clinching may be referred to as penetration joining in consideration of its shape.

[0098] Thus, when manufacturing the cooling member 500, if a mechanical fastening method is applied instead of a welding connection method, excessive heat will not be generated during the manufacturing process. Therefore, unintended deformation of the cooling member 500 is minimized, and dimensional stability can be ensured by reducing the difference between the pre-designed dimensions and the dimensions of the final product. In particular, in the case of the aluminum material that has been mainly used for the cooling member 500, it begins to deform when a temperature of 660 °C or higher, which is its melting point, is applied. However, if the above-described mechanical fastening method is applied, heat above the melting point will not be applied to the cooling member 500, so the dimensional stability of the cooling member 500 can be further improved.

[0099] In addition, if a mechanical fastening method is applied during the manufacturing of the cooling member 500, specific materials that are vulnerable to temperature will not deform during the manufacturing process. Therefore, various materials and shaped structures can be applied to the cooling member 500, and the design of the cooling member 500 can be easier and more diverse.

[0100] On the other hand, when a mechanical fastening method is applied during the manufacturing of the cooling member 500, in order to further improve the watertightness between the upper plate 510 and the lower plate 520, an elastic member 590 can be positioned between the upper plate 510 and the lower plate 520. When applying the conventional welding connection method, it was difficult to provide the elastic member 590, which is slightly vulnerable to heat, during the connection of the upper plate 510 and the lower plate 520. Therefore, when using the welding process, in order to complement the watertightness of the welding surface, mainly after the connection of the upper plate 510 and the lower plate 520, a sealant or the like was applied by an additional process. However, since the cooling member 500 according to this embodiment is formed by a mechanical connection method, the elastic member 590, which is vulnerable to heat, can be joined together during the joining process of the upper plate 510 and the lower plate 520. As a result, simplification of the manufacturing process and reduction of manufacturing costs can be achieved.

[0101] The elastic member 590 can include a strip-shaped elastic member 592 disposed at the periphery of the cooling member 500. The strip-shaped elastic member 592 is provided on the surface where the upper plate 510 and the lower plate 520 contact each other, and can improve the watertightness between the upper plate 510 and the lower plate 520. When the upper plate 510 and the lower plate 520 are joined, the strip-shaped elastic member 592 can be compressed by an external force to fill the gap existing between the upper plate 510 and the lower plate 520. The strip-shaped elastic member 592 can prevent the cooling water inside the cooling member 500 from flowing out through the gap. Here, the strip-shaped elastic member 592 may be referred to as a water pad.

[0102] The elastic member 590 can include a ring-shaped elastic member 594. When the cooling member 500 is formed by a rivet or the like, a fastener is formed at the fastening portion, so the fastening portion has a problem that it may reduce the watertightness of the cooling member 500. However, the watertightness of the fastening portion can be complemented through the ring-shaped elastic member 594. When the cover film 580 is provided on the cooling member 500, the ring-shaped elastic member 594 can be located on the cover film 580, and by sealing the gap around the fastening portion, the watertightness of the cooling member 500 can be improved. Here, the ring-shaped elastic member 594 may be referred to as a "water ring".

[0103] The elastic member 590 is made of a flexible material having elasticity. Examples of the material for manufacturing the elastic member 590 include silicone-based foam pads, acrylic-based foam pads, or urethane-based foam pads.

[0104] Hereinafter, a battery pack according to still another embodiment of the present invention will be described.

[0105] The battery pack of the embodiment described below is the same as the content of the above-described embodiment except that the structure of the cooling member is different. Therefore, in describing this embodiment, the same drawing numbers are assigned to the configurations common to the above-described embodiment, and detailed descriptions are omitted.

[0106] FIG. 10 is a perspective view of a lower plate of a cooling member included in a battery pack according to still another embodiment of the present invention. FIG. 11 is a view showing an example of a cross section taken along line A-A of FIG. 10. FIG. 12 is a cross-sectional view of the lower plate for explaining a modified example of the cooling member according to FIG. 10. FIG. 13 is a cross-sectional view of the lower plate for explaining another modified example of the cooling member according to FIG. 10. FIG. 14 is a cross-sectional view of the cooling member for explaining still another modified example of the cooling member according to FIG. 10.

[0107] Referring to FIGS. 10 to 14, the vulnerable part 600 of the present embodiment may be a part having a relatively small thickness value compared to other parts of the lower plate 520. Specifically, the lower plate 520 may have a first part called the vulnerable part 600 and a second part where the vulnerable part 600 is not formed, and here, the thickness of the second part is larger than the thickness of the first part. The thickness value of the first part may be half or less of the thickness value of the second part. The vulnerable part 600 can be relatively easily opened by heat or pressure by having a slightly smaller thickness value than other parts.

[0108] Referring to FIG. 10, the lower plate 520 of the cooling member 500 according to the present embodiment may include at least one groove part 522. The groove part 522 may be a part formed with a thin thickness so as to be easily broken by high temperature or high pressure when the battery cell catches fire. Therefore, in the present embodiment, the vulnerable part 600 may be a part where the groove part 522 is formed in the lower plate 520 or may refer to the groove part 522.

[0109] In the above-described embodiment, since the cooling water is located between the upper plate 510 and the lower plate 520 and directly contacts the lower plate 520 where the vulnerable part 600 is formed, there is a problem that the cooling water may leak through the gap around the opening 521. In addition, manufacturing the lower plate 520 to include two materials having different physical properties involves a complicated manufacturing process, so the manufacturing time and manufacturing cost may increase. However, in the cooling member 500 of the present embodiment, since the lower plate 520 does not have a sealing member 529 or a cover film 580 having a low melting point and the opening 521 is not formed in the lower plate 520, minimization of the decrease in watertightness and simplification of the manufacturing process can be achieved.

[0110] Referring to FIG. 11, the cross-section of the groove portion 522 can have various shapes. The groove portion 522 can have a quadrangular cross-sectional shape as shown in FIG. 11(a) when a first portion where the groove portion 522 is formed and a second portion where the groove portion 522 is not formed are perpendicularly connected to each other. Further, when an inclination is formed on the connection surface between the above-described first portion and the second portion, a part of the lower plate 520 can have a triangular cross-sectional shape as shown in FIG. 11(b) or a trapezoidal cross-sectional shape as shown in FIG. 11(d). When the connection surface between the first portion and the second portion is formed to have a curvature, a part of the lower plate 520 may have a round cross-section as shown in FIG. 11(c). On the other hand, the cross-sectional shape of the lower plate 520 due to the formation of the groove portion 522 is not limited by the above-described examples and can be variously deformed in consideration of ease of design and the like.

[0111] When considering that the fragile portion 600 must break due to heat or temperature, since it is preferable that the fragile portion 600 contains as many thin portions as possible, other shapes in FIG. 11 are more preferable than the shape in FIG. 11(b). However, since the breaking temperature and pressure may be affected by factors such as thickness, physical properties, and shape, other shapes in FIG. 11 are not necessarily more preferable than the shape in FIG. 11(b).

[0112] Referring to FIG. 12, the groove portion 522 formed in the lower plate 520 may be exposed to the outside instead of facing the inside of the cooling member 500. At this time, the lower surface of the cooling member 500 can have a locally protruding shape, and the protruding lower surface of the cooling member 500 can promote heat dissipation of the battery cell by being located close to or in contact with the battery cell. Since the cross-sectional shape shown in FIG. 12 can be described with reference to the content of FIG. 11 except that the up-and-down direction is opposite, a detailed description is omitted.

[0113] On the other hand, the groove portion 522 of the present embodiment can be formed in various ways.

[0114] For example, the groove portion 522 is formed by partially etching the lower plate 520. The groove portion 522 is formed using a notching process.

[0115] As another example, the lower plate 520 is formed by joining two layers, thereby forming a weak portion 600, that is, the groove portion 522.

[0116] Referring to FIG. 13, the lower plate 520 is formed by joining a first layer 520A provided as a plate-shaped member and a second layer 520B having a plurality of holes. The above-described groove portion 522 or weak portion 600 is formed by the holes formed in the second layer 520B. For reference, in FIG. 13, except for the first layer 520A, the hatched portion indicates the second layer 520B, and the partially empty space between the hatches represents the cross-section of the holes formed in the second layer 520B.

[0117] A part of the lower plate 520 can have a relatively large thickness by including the first layer 520A and the second layer 520B, and another part of the lower plate 520 can have a relatively small thickness by including only the first layer 520A. Here, the portion having the first layer 520A may be referred to as the first portion, and the portion having both the first layer 520A and the second layer 520B may be referred to as the second portion. Therefore, the thickness of the first portion can correspond to the thickness of the first layer 520A, and the thickness of the second portion can correspond to the thicknesses of the first layer 520A and the second layer 520B.

[0118] On the other hand, compared with the case where the weak portion 600 is formed by a notching process or the like, when formed by joining two layers as shown in FIG. 13, the dimensional stability of the weak portion 600 is improved, and the process costs and process times due to defective products can be minimized.

[0119] Specifically, when the groove portion 522 is formed by an etching process, the equipment used for this is difficult to control to a precise level. When the thickness of the lower plate 520 is thin, or when the thickness of the desired weak portion 600 is thin, there is a risk that the lower plate 520 may be damaged during the process of forming the groove portion 522. Specifically, in order for the lower plate 520 to be provided with the weak portion 600, a thickness at the thin film level must be formed by removing a part of the already sufficiently thin lower plate 520. If the control of the device is not perfect, the lower plate 520 may be damaged, or the dimensional stability of the weak portion 600 may decrease, resulting in waste of process costs and process time due to an increase in defective products.

[0120] When the lower plate 520 is formed by joining two layers, since the thickness of each layer can be freely adjusted, the weak portion 600 is formed to be sufficiently thin. The first layer 520A forming the weak portion 600 is provided with an aluminum material that can be melted or broken by temperature, pressure, and spark during a thermal runaway phenomenon. At this time, the thickness of the first layer 520A can be designed to be sufficiently thick up to a level that can be melted by the thermal runaway of the battery cell. Specifically, the first layer 520A is provided with a thickness of 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, or 0.1 mm or less.

[0121] For example, when both the first layer 520A and the second layer 520B are provided with aluminum, the first layer 520A is provided with an aluminum plate having a thickness of 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, or 0.1 mm or less, and the second layer 520B is provided in a state where holes are formed in an aluminum plate having a thickness of 1.0 to 1.5 mm or more. Also, according to an embodiment, the first layer 520A may be provided even thinner, for example, with an aluminum plate having a thickness of 0.03 to 0.07 mm, or 0.04 to 0.06 mm, or 0.05 mm. When the aluminum plates of the second layer 520B are joined to one surface of the first layer 520A in this way, a lower plate 520 having a weak portion 600 with a sufficiently thin thickness is formed.

[0122] Also, when the lower plate 520 is formed by joining two layers, the thickness values of all the vulnerable parts 600 may be the same as each other. When the first vulnerable part and the second vulnerable part are formed on the lower plate 520, the thicknesses of the first vulnerable part and the second vulnerable part may be substantially the same as each other. The thickness value of each vulnerable part 600 does not show deviation depending on its position. When a thickness deviation due to position occurs in the vulnerable part 600, a part of it may be formed thicker than designed, and as a result, a specific part may be less likely to break due to heat or pressure. Since the vulnerable parts 600 of this embodiment are formed to have a uniform thickness, the error between the design and the actual product can be minimized.

[0123] Various bonding processes can be applied to the bonding of the two layers forming the lower plate 520. Since cooling water is located on the upper surface of the lower plate 520, the bonding of the two layers needs to be formed firmly.

[0124] As an example, the bonding of the two layers is formed by a welding process. Examples of the welding process used for the bonding include brazing or laser welding. By applying a temperature similar to the melting point of the material to the two layers, the two layers are fusion-bonded. By fusion-bonding, the watertightness of the lower plate 520 can be achieved at a desired level.

[0125] As another example, the bonding of the two layers is formed by a rolling process. The rolling process is a method of bonding two layers by passing a laminate in which two or more layers are laminated between a pair of rolls. During the interlayer bonding by the rolling process, the laminate can be heated. At this time, if the heating temperature is above the recrystallization temperature of the metal, it is called hot roll, and if it is below the temperature, it is called cold roll. By applying pressure and / or heat to the laminate, a wide bonding surface is formed between the two layers, and thereby, the watertightness of the lower plate 520 can be sufficiently ensured.

[0126] On the one hand, when the lower plate 520 is formed by bonding two layers, the materials of the two layers may be different from each other, or may be the same or similar to each other. When the materials of the two layers are the same or similar to each other, since the melting points of the two layers are the same / similar, the above-described bonding process involving heat or pressure can be performed more easily.

[0127] On the other hand, when bonding two layers by a soldering process, the bonding process may not proceed smoothly due to the physical properties or melting point of the metal. For example, when the two layers are formed of aluminum of a single property, if the temperature of the soldering process is set to the level of 660°C, which is the melting point of aluminum, shape deformation of the aluminum layer may occur during the bonding process. To prevent such deformation of the layer, the first layer 520A or the second layer 520B is manufactured from a clad metal, which is a double-layer metal material.

[0128] For example, the bonding of the layers is formed by a soldering process. When the first layer 520A is located below the second layer 520B, the cross-section of the lower plate 520 is provided with a structure similar to that of FIG. 11. Here, the first layer 520A may be 3000-series aluminum, and the second layer 520B may be a clad metal containing 3000-series and 4000-series aluminum. By including a clad metal in the second layer 520B, the temperature of the soldering process is set to the level of 600°C, whereby shape deformation of aluminum can be prevented during the bonding process. At this time, the upper plate 510 may be 3000-series aluminum.

[0129] As another example, the bonding of the layers is formed by a brazing process. With the first layer 520A positioned above the second layer 520B, the cross-section of the lower plate 520 is provided with a structure similar to that of FIG. 12. Here, the first layer 520A can include 3000-series and 4000-series clad metals, and the second layer 520B can include 3000-series aluminum. At this time, the upper plate 510 may also be 3000-series aluminum, or the bonding between the layers is smoothly performed by 4000-series aluminum formed on the upper and lower surfaces of the first layer 520A provided with the clad metal. Alternatively, the first layer 520A may be provided with 3000-series aluminum, and the second layer 520B or the upper plate 510 may be provided with 3000-series and 4000-series clad metals.

[0130] On the other hand, referring to FIG. 14, the cooling member 500 can be described as having three layers. Specifically, the upper plate 510 of the cooling member 500 can have one layer, and the lower plate 520 can have two layers. Here, since the lower plate 520 having two layers has been sufficiently described by the above-mentioned content, a detailed description is omitted.

[0131] In the cooling member 500, since the cooling water is built in between the upper plate 510 and the lower plate 520, the flow rate deviation of the cooling water can be determined according to the separation distance between the upper plate 510 and the lower plate 520. The flow rate deviation of the cooling member 500 can depend on the thickness difference of the lower plate 520. Specifically, the periphery of the first part where the vulnerable part 600 is formed has a relatively large flow rate per unit length, and the periphery of the second part where the vulnerable part 600 is not formed has a relatively small flow rate per unit length. If the flow rate of the periphery of the first part is larger, the cooling water can be injected faster by the hydraulic pressure when the vulnerable part 600 is opened, so the larger the flow rate of the periphery of the first part, the more preferable.

[0132] Therefore, in this embodiment, an upper plate 510 having a bent portion 514 is provided so that a flow rate deviation of the cooling water in the cooling member 500 is formed. The bent portion 514 can have a waveform cross-sectional shape based on the longitudinal cross-section of the cooling member 500. Here, based on the cross-section, the highest point of the bent portion 514, that is, the crest, can correspond to the first portion of the lower plate 520 where the vulnerable portion 600 is formed. Also, the lowest point of the bent portion 514, that is, the trough, can correspond to the second portion of the lower plate 520. By the correspondence between the crest of the bent portion 514 and the first portion, the flow rate per unit length around the first portion increases, and when the vulnerable portion 600 is opened, the cooling water in the cooling member 500 is injected faster toward the first battery cell 110A where the ignition phenomenon has occurred.

[0133] On the other hand, in FIG. 14, it is shown that each layer of the cooling member 500 is positioned in the order of the first layer 520A, the second layer 520B, and the upper plate 510, but it is also possible to be positioned in the order of the second layer 520B, the first layer 520A, and the upper plate 510. In this case, since the second layer 520B forming the lower surface of the cooling member 500 is located close to or in contact with the battery cell, the effect of promoting heat dissipation of the battery cell by the second layer 520B will appear.

[0134] Also, in the cooling member 500 as shown in FIG. 14, the upper plate 510 may be referred to as the third layer and is made of aluminum. When the third layer is formed of aluminum, the upper plate 510 is preferably formed to have a thickness of 1.0 to 2.0 mm, 1.3 to 1.7 mm, or at the level of 1.5 mm. Further, the second layer 520B included in the lower plate 520 is preferably formed to have a thickness of 1.0 to 1.5 mm, 1.2 to 1.4 mm, or at the level of 1.3 mm. The first layer 520A can have a thickness of 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, or 0.1 mm or less. Note that the first layer 520A may be formed sufficiently thin so as to have the characteristics of the vulnerable portion 600, and specifically, it can have a thickness of 0.03 to 0.07 mm, or 0.04 to 0.06 mm.

[0135] Regarding the interlayer bonding in the cooling member 500 having three layers, various bonding processes such as welding and rolling processes can be applied. In the cooling member 500 including three layers, when the bonding of the layers is formed by brazing, the physical properties of the first layer 520A, the second layer 520B, and the third layer which is the upper plate 510 can be explained by the above description, so detailed description is omitted.

[0136] Hereinafter, a battery pack according to still another embodiment of the present invention will be described.

[0137] The battery pack of the embodiment described below is the same as the content of the above-described embodiment except for the different structure of the cooling member. Therefore, in describing this embodiment, the same drawing numbers are assigned to the configurations common to the above-described embodiment, and detailed description is omitted.

[0138] FIG. 15 is a perspective view of a cooling member included in a battery pack according to still another embodiment of the present invention. FIG. 16 is a top view of a cooling member included in a battery pack according to still another embodiment of the present invention. FIG. 17 is a view showing the connection between the lower plate, the cooling tube, and the cooling hose included in the cooling member according to FIG. 15. FIG. 18 is a view showing a section along the line B-B of the cooling member according to FIG. 16, and shows that cooling water flows into and out of the cooling tube and the cooling hose. FIG. 19 is a sectional view along the line B-B of the cooling member according to FIG. 16, and shows the injection of cooling water by the cooling hose when the battery cell ignites.

[0139] Referring to FIGS. 15 to 17, the cooling member 500 of this embodiment can include a cooling tube 540 and a cooling hose 550 through which cooling water flows. The lower plate 520 is preferably provided in a plate shape to support the cooling tube 540 and the like. The upper plate 510 can be replaced by the cooling tube 540 and the like and omitted. The cooling member 500 is manufactured by mounting the cooling tube 540 on the upper surface of the lower plate 520, mounting the cooling hose 550 on the cooling tube 540, and then coupling the fixing member 560 to the lower plate 520.

[0140] In the above-described embodiment, since the cooling water is located between the upper plate 510 and the lower plate 520 and directly contacts the lower plate 520 where the vulnerable part 600 is formed, there is a problem that the cooling water may leak through the gap around the opening 521. In addition, manufacturing the lower plate 520 to include two materials with different physical properties involves a complicated manufacturing process, so the manufacturing time and cost may increase. However, in the cooling member 500 of the present embodiment, the cooling water is isolated in the cooling tube 540 or the cooling hose 550, so that the reduction in watertightness due to the opening 521 can be minimized. Further, by coupling the lower plate 520, the cooling tube 540, and the cooling hose 550 via the fixing member 560, the manufacturing process of the cooling member 500 is simplified, and the manufacturing time and cost are saved.

[0141] Referring to FIG. 17, the lower plate 520 may include at least one opening 521. The opening 521 may be for injecting the internal cooling water into the battery cell by heat or pressure generated by ignition when the battery cell internally ignites. Around the lower plate 520, a protrusion 524 is formed that extends from one side of the lower plate 520 and is continuously located along a corner of the lower plate 520. The protrusion 524 can promote heat dissipation of the portion by contacting or being disposed in proximity to the electrode lead of each battery cell laminate or the bus bar connected to the electrode lead. Further, a step 526 is formed on the lower plate 520. The step 526 can extend along the longitudinal direction of the cooling member 500 from the center in the width direction of the cooling member 500 except for a predetermined section. The cooling tube 540 is mounted in place by the step 526, and the fixing member 560 is stably fixed. Here, the width direction of the cooling member 500 may be a direction parallel to the short side of the cooling member 500. The longitudinal direction of the cooling member 500 may be a direction parallel to the long side of the cooling member 500.

[0142] Referring to FIGS. 17 and 18, the cooling tube 540 can provide a flow path for cooling water for heat dissipation of the battery cell. Inside the cooling tube 540, the cooling water injected through the inlet port 532 is accommodated, and the cooling water accommodated in the cooling tube 540 is discharged through the outlet port 534. By the inflow or outflow of the cooling water into or from the cooling tube 540, the cooling member 500 can be maintained at a relatively constant temperature. The cooling water in the cooling tube 540 can be designed to be continuously circulated by being connected to an external heat exchanger connected to the inlet / outlet port 530 in order to maintain the constancy of its temperature.

[0143] The lower plate 520 cooled by the cooling tube 540 can promote heat dissipation of the battery cell. The cooling tube 540 is made of a material with high thermal conductivity, whereby the heat of the lower plate 520 can be quickly absorbed. The cooling tube 540 is made of a material having sufficient rigidity to withstand the pressure and weight of the cooling water accommodated therein. The cooling tube 540 is made of the same material as or a similar material to the material of the lower plate 520. Examples of the material of the cooling tube 540 include aluminum, gold, silver, copper, platinum, or an alloy containing these.

[0144] The cooling tube 540 is mounted at a position on the lower plate 520 where the small step 526 is not formed. The outer shape of the cooling tube 540 may be similar to the outer shape of the lower plate 520 excluding the protruding portion 524.

[0145] The cooling tube 540 can have a square tubular shape and can be branched into two parts corresponding to the inlet port 532 and the outlet port 534 respectively in consideration of the position of the small step 526. Thereby, the cooling tube 540 can form a U-shaped flow path. The cooling tube 540 includes a first portion 542 extending along a straight line parallel to the longitudinal direction of the cooling member 500 from the inlet port 532, a second portion 544 extending along a curve rotating clockwise or counterclockwise from the end of the first portion 542, and a third portion 546 extending along a straight line parallel to the longitudinal direction of the cooling member 500 from the end of the second portion 544 toward the outlet port 534.

[0146] The cooling tube 540 can include a housing portion 548 to which the cooling hose 550 is attached. The housing portion 548 may mean a housing space in the cooling tube 540 where the cooling hose 550 is attached. The housing portion 548 may be a long groove extending along the longitudinal direction of the cooling member 500, or the cross-section of the housing portion 548 may be a polygon such as a quadrilateral or a circle. At both longitudinal ends of the housing portion 548, both longitudinal ends of the cooling hose 550 are connected. At both longitudinal ends of the housing portion 548, both ends of the cooling hose 550 are inserted. The connection portions between both longitudinal ends of the housing portion 548 and both ends of the cooling hose 550 can be sealed to ensure watertightness. For example, a gasket is provided at the connection portion between the cooling hose 550 and the housing portion 548, and watertightness between the two members can be ensured via the gasket. As another example, at both ends of the cooling hose 550, expansion portions extending in the circumferential direction from the ends of the cooling hose 550 are formed, and the expansion portions can complement the connection between the cooling hose 550 and the cooling tube 540 by being inserted into the ends of the housing portion 548 and positioned inside the cooling tube 540. As yet another example, at the end of the cooling hose 550, a first expansion portion extending in the circumferential direction and a second expansion portion spaced apart from the first expansion portion are formed. The first expansion portion can be positioned inside the cooling tube 540, and the second expansion portion can be positioned outside the cooling tube 540. The connection between the cooling hose 550 and the cooling tube 540 may be more complemented by the two expansion portions being in close contact with the cooling tube 540. Also, at this time, protrusions may be formed on the expansion portion, the first expansion portion, or the second expansion portion, and the connection may be made in closer contact with one side surface of the cooling tube 540 via the protrusions.

[0147] The cooling hose 550 can be connected to the cooling tube 540 to provide a flow path for the cooling water that realizes heat dissipation of the battery cell. The cooling water flowing in from the inlet / outlet port 530 can move through the cooling hose 550. The cooling hose 550 is supplied with cooling water from the cooling tube 540 located near the inlet / outlet port 530.

[0148] The fixing member 560 may be for complementing the rigidity of the cooling member 500 by fixing the lower plate 520, the cooling tube 540, and the cooling hose 550. The fixing member 560 can fix the positions of the cooling tube 540 and the cooling hose 550 by being coupled to the lower plate 520.

[0149] The fixing member 560 is provided in the shape of a strap having a length. The fixing member 560 can be positioned parallel to the width direction of the cooling member 500. A plurality of fixing members 560 are provided along the longitudinal direction of the cooling member 500, and the plurality of fixing members 560 are arranged at uniform intervals.

[0150] The fixing member 560 is manufactured from a highly rigid material to maintain the shape of the cooling member 500 and, as an example, is manufactured from metal.

[0151] The fixing member 560 is coupled to both ends in the width direction of the cooling member 500. The fixing member 560 is coupled to the center in the width direction of the cooling member 500. The fixing member 560 can include end coupling portions 562 respectively formed at both ends in the longitudinal direction of the fixing member 560 and a center coupling portion 564 formed at the center in the longitudinal direction of the fixing member 560. The end coupling portion 562 of the fixing member 560 is coupled to the protruding portions 524 located at both ends in the width direction of the lower plate 520. The center coupling portion 564 of the fixing member 560 is coupled to the small step 526 located at the center in the width direction of the lower plate 520. The end coupling portion 562 and the center coupling portion 564 are formed to have a step with other portions of the fixing member 560 and can have a height slightly lower than that of other portions of the fixing member 560. When considering the shapes of the protruding portion 524 and the small step 526, the end coupling portion 562 is formed to have a larger step than the center coupling portion 564.

[0152] Thus, when the fixing member 560 is used in the manufacturing of the cooling member 500, compared with bonding methods such as welding processes, excessive heat is not generated during the manufacturing process, so specific materials vulnerable to temperature do not deform during the manufacturing process. Therefore, by using the fixing member 560, the cooling member 500 is manufactured to include two or more materials with different properties, and structures of various materials and shapes such as the cooling hose 550 can be applied to the cooling member 500, and the design of the cooling member 500 can be easier and more diverse.

[0153] Referring to FIG. 19, the cooling hose 550 can be positioned to correspond to the opening 521 of the lower plate 520. The cooling hose 550 can introduce internal cooling water toward the battery cell by melting or breaking during an internal fire. When the battery cell ignites, a part of the cooling hose 550 corresponding to the opening 521 is opened by melting or breaking, whereby the cooling water is jetted, ejected, and introduced in the direction of gravity, and the fire of the battery cell located below the cooling member 500 can be suppressed. On the other hand, in order to realize such an effect, the accommodating part 548 to which the cooling hose 550 is attached must also be formed to correspond to the opening 521 of the lower plate 520.

[0154] When considering the structure of this embodiment as described above, the vulnerable part 600 of this embodiment may refer to the part of the lower plate 520 where the opening 521 is located. The vulnerable part 600 may refer to the part of the lower plate 520 where the opening 521 closed by the cooling hose 550 is formed.

[0155] The cooling hose 550 is manufactured from a material that melts or breaks at a predetermined temperature or pressure. The cooling hose 550 is manufactured from the same or a similar material as the sealing member 529 of the above-described embodiment.

[0156] On the other hand, in order to achieve the above-described effects, it would also be possible to configure such that the cooling hose 550 is not separately manufactured and a part of the cooling tube 540 is broken to allow the cooling water to be introduced. However, in order for the cooling tube 540 to withstand the pressure of the cooling water flowing into it and maintain its form, the cooling tube 540 must be manufactured from a material having sufficient rigidity. Therefore, manufacturing it from a material that is easily melted by heat or easily broken by pressure may cause a problem of reducing the overall durability of the cooling member 500. Thus, as in this embodiment, separately configuring the cooling hose 550, which is easily broken by heat, from the cooling tube 540 is preferable for improving the performance of the entire cooling member 500.

[0157] On the other hand, a battery pack according to an embodiment of the present invention may additionally include a battery management system (Battery Management System; BMS) that manages the temperature, voltage, etc. of the battery and / or a cooling device, etc.

[0158] A battery pack according to an embodiment of the present invention is applicable to various devices. For example, the device to which the battery pack is applied may be a means of transportation such as an electric bicycle, an electric vehicle, or a hybrid vehicle. However, the above-described devices are not limited thereto. In addition to the above-described examples, the battery pack according to this embodiment can be used for various devices, and this also belongs to the scope of the rights of the present invention.

[0159] As described above, the preferred embodiments of the present invention have been described in detail. However, the scope of the rights of the present invention is not limited thereto, and various modifications and improvements 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 rights of the present invention.

Explanation of Reference Numerals

[0160] 1000: Battery pack 100: Cell block 110: Battery cell 120: Battery cell laminate 130: Side plate 140: Holding strap 150: Bus bar frame 200: Pack frame 300: Resin layer 400: End plate 500: Cooling member 510: Upper plate 520: Lower plate 530: Inlet / Outlet port 540: Cooling tube 550: Cooling hose 560: Fixing member 580: Cover film 590: Elastic member 600: Weak part 700: Foam pad

Claims

1. A battery cell stack in which a plurality of battery cells are stacked, a pack frame that houses the battery cell stack, a cooling member containing cooling water and located above the battery cell stack, and a foam pad located between the battery cell stack and the lower plate of the cooling member, wherein at least one weak part that breaks or melts at a predetermined temperature or pressure or higher is formed on the lower plate of the cooling member, and when the weak part of the cooling member is opened, the movement path of the cooling water discharged toward the battery cell stack is guided by the foam pad, a battery pack.

2. The foam pad includes at least one opening, and the opening of the foam pad corresponds to the weak part, the battery pack according to Claim 1.

3. A battery cell stack in which a plurality of battery cells are stacked, a pack frame that houses the battery cell stack, a cooling member containing cooling water and located above the battery cell stack, and a foam pad located between the battery cell stack and the cooling member, wherein at least one weak part that breaks or melts at a predetermined temperature or pressure or higher is formed on the lower plate of the cooling member, and when the weak part of the cooling member is opened, the movement path of the cooling water discharged toward the battery cell stack is guided by the foam pad, and a part of the cooling water discharged toward the battery cell stack is absorbed by the foam pad, a battery pack.

4. There are a plurality of the battery cell stacks, and the foam pad corresponds to all of the respective battery cell stacks, the battery pack according to Claim 1.

5. A plurality of openings are formed in the lower plate, and the openings are closed by a sealing member, and the weak part is a part of the lower plate where the openings closed by the sealing member are located, the battery pack according to Claim 1.

6. A battery cell stack in which a plurality of battery cells are stacked, a pack frame that houses the battery cell stack, a cooling member containing cooling water and located above the battery cell stack, and a foam pad located between the battery cell stack and the cooling member, wherein at least one weak part that breaks or melts at a predetermined temperature or pressure or higher is formed on the lower plate of the cooling member, When the vulnerable part of the cooling member is opened, the movement path of the cooling water discharged toward the battery cell laminate is guided by the foam pad. The cooling member includes a cooling tube that provides a flow path for the cooling water and a cooling hose attached to the cooling tube. A plurality of openings are formed in the lower plate, and the cooling hose is positioned corresponding to the openings. The battery pack, wherein the vulnerable part is a part of the lower plate where the opening closed by the cooling hose is located.

7. The battery pack according to claim 6, wherein the lower plate and the cooling tube are connected by a strap-shaped fixing member.

8. The lower plate includes a first part where the vulnerable part is formed and a second part where the vulnerable part is not formed. The battery pack according to claim 1, wherein the thickness value of the first part is smaller than the thickness value of the second part.

9. The battery pack according to claim 8, wherein the thickness value of the first part is less than or equal to half of the thickness value of the second part.

10. A battery cell laminate in which a plurality of battery cells are laminated, A pack frame that houses the battery cell laminate, A cooling member located above the battery cell laminate and containing cooling water, And a foam pad located between the battery cell laminate and the cooling member. At least one vulnerable part that breaks or melts at a predetermined temperature or pressure or higher is formed on the lower plate of the cooling member. When the vulnerable part of the cooling member is opened, the movement path of the cooling water discharged toward the battery cell laminate is guided by the foam pad. The lower plate includes a first part where the vulnerable part is formed and a second part where the vulnerable part is not formed. The thickness value of the first part is smaller than the thickness value of the second part. The lower plate is formed by joining a first layer and a second layer having different thicknesses. The thickness of the first part corresponds to the thickness of the first layer. The battery pack, wherein the thickness of the second part corresponds to the thicknesses of the first layer and the second layer.

11. A battery cell laminate in which a plurality of battery cells are laminated, A pack frame that houses the battery cell laminate, A cooling member located above the battery cell laminate and containing cooling water, And a foam pad located between the battery cell laminate and the cooling member. At least one weak portion that breaks or melts at a predetermined temperature or pressure or higher is formed on the lower plate of the cooling member. When the weak portion of the cooling member is opened, the movement path of the cooling water discharged toward the battery cell laminate is guided by the foam pad. The lower plate includes a first portion where the weak portion is formed and a second portion where the weak portion is not formed. The thickness value of the first portion is smaller than the thickness value of the second portion. The upper plate coupled to the lower plate of the cooling member includes a bent portion. The peak of the bent portion corresponds to the first portion. The valley of the bent portion corresponds to the second portion, a battery pack.

12. The cooling member further includes an in / out port for injecting cooling water into the internal space of the cooling member. The in / out port is connected to an external heat exchanger. The battery pack according to claim 1, wherein the cooling water of the cooling member circulates through the in / out port.

13. The battery pack according to claim 1, wherein the upper plate of the cooling member is integrated with the pack frame.

14. A device including the battery pack according to any one of claims 1 to 13.

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