Battery pack and device including same

Abstract

A battery pack according to one embodiment of the present invention includes a battery module including a cell stack in which one or more battery cells are stacked and a module frame that houses the cell stack; a pack frame that houses the battery module; and a thermally conductive resin layer positioned between a lower surface of the module frame and the pack frame, wherein an opening is formed in the lower surface of the module frame so that the cell stack comes into contact with the thermally conductive resin layer.

Description

[Technical field]

[0001] Cross-reference to related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0075829 filed on June 25, 2019, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery pack and a device including the same, and more particularly to a battery pack including one or more battery modules and a device including the same. [Background technology]

[0003] In modern society, as the use of portable devices such as mobile phones, laptops, camcorders, and digital cameras has become commonplace, the development of technologies related to such mobile devices has become active. In addition, rechargeable secondary batteries are used as the power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), etc. as a solution to air pollution caused by existing gasoline-powered vehicles that use fossil fuels, and the need for the development of secondary batteries is increasing.

[0004] Currently, commercial secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Of these, lithium secondary batteries are attracting attention due to their advantages over nickel-based secondary batteries, such as almost no memory effect, freedom in charging and discharging, a very low self-discharge rate, and high energy density.

[0005] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative active materials, respectively, and include an electrode assembly in which positive and negative electrode plates coated with the positive and negative active materials are disposed with a separator therebetween, and an exterior material, i.e., a battery case, that hermetically houses the electrode assembly together with an electrolyte.

[0006] Generally, lithium secondary batteries can be classified into can-type secondary batteries, in which an electrode assembly is housed inside a metal can, and pouch-type secondary batteries, in which an electrode assembly is housed inside a pouch made of an aluminum laminate sheet, depending on the shape of the exterior material.

[0007] In the case of secondary batteries used in small devices, two to three battery cells are arranged, whereas in the case of secondary batteries used in medium to large devices such as automobiles, a battery module in which a number of battery cells are electrically connected is used. In such battery modules, a number of battery cells are connected to each other in series or parallel to form a cell stack, thereby improving capacity and output. In addition, one or more battery modules may be mounted with various control and protection systems such as a BMS (Battery Management System) and a cooling system to form a battery pack.

[0008] If the temperature of a secondary battery becomes higher than the appropriate temperature, the performance of the secondary battery may be degraded, and if the temperature is severe, there is a risk of explosion or fire. In particular, in a battery module or battery pack having a large number of secondary batteries, i.e., battery cells, the temperature may rise faster and more rapidly due to the sum of heat generated from the large number of battery cells in a small space. In other words, a battery module in which a large number of battery cells are stacked and a battery pack equipped with such a battery module can obtain high output, but it is difficult to remove the heat generated in the battery cells during charging and discharging. If the heat of the battery cells is not dissipated well, the battery cells will deteriorate faster, shortening their lifespan and increasing the possibility of explosion or fire.

[0009] Furthermore, battery modules included in vehicle battery packs are often exposed to direct sunlight and may be placed in high temperature conditions, such as in summer or in desert regions.

[0010] Therefore, it is very important to ensure stable and effective cooling performance when constructing a battery module or battery pack.So, thermal pads and heat sinks are used as cooling means for battery packs to dissipate heat generated in battery cells to the outside, but there is a problem that effective cooling is difficult because of factors that hinder cooling performance such as air gaps due to the complex structure connecting the battery cells and battery module, and the battery module and battery pack.

[0011] In addition, other demands such as miniaturization, increased rigidity, and increased capacity continue to be placed on battery packs, so it is essentially necessary to develop a battery module that can meet all of these diverse demands while improving cooling performance. Summary of the Invention [Problem to be solved by the invention]

[0012] The embodiments of the present invention have been proposed to solve the above problems, and an object of the present invention is to provide a battery pack and a device including the same, which have increased capacity and output as well as improved cooling performance.

[0013] However, the problems to be solved by the embodiments of the present invention are not limited to the problems described above, and may be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0014] A battery pack according to one embodiment of the present invention includes a battery module including a cell stack in which one or more battery cells are stacked and a module frame that houses the cell stack, a pack frame that houses the battery module, and a thermally conductive resin layer located between a lower surface of the module frame and the pack frame, and an opening is formed in the lower surface of the module frame so that the cell stack comes into contact with the thermally conductive resin layer.

[0015] The thermally conductive resin layer may include a thermally conductive adhesive material.

[0016] The thermally conductive resin layer may be in a form in which the thermally conductive resin is solidified while remaining in contact with the cell stack.

[0017] The battery pack may further include a heat sink located between the thermally conductive resin layer and a bottom of the pack frame.

[0018] At least one of the module frames may be a U-shaped frame, and the opening may be formed in a lower surface of the U-shaped frame.

[0019] A cover may be positioned on an upper surface of the U-shaped frame, and the U-shaped frame and the cover may be welded together to form a joint.

[0020] At least one of the module frames may be a monoframe having an open front and rear, and the opening may be formed in a lower surface of the monoframe.

[0021] The battery module may be two or more.

[0022] The pack frame may include partitions formed between side surfaces of the battery modules.

[0023] A side surface of the battery module may be in intimate contact with the barrier rib.

[0024] The battery modules arranged along a lateral direction of the battery modules may be in close contact with each other at their lateral sides.

[0025] The one or more battery cells may be stacked in an upright or inverted manner so as to be parallel to both sides of the module frame, and each of the one or more battery cells may be in contact with the thermally conductive resin layer.

[0026] The openings may be spaced apart from each of the front and rear faces of the module frame.

[0027] The opening may be adjacent to both sides of the module frame. Effect of the Invention

[0028] According to an embodiment of the present invention, a battery pack having improved cooling performance can be provided by reducing cooling obstruction factors through an exposure structure of a battery cell formed in a module frame of a battery module.

[0029] In addition, since there is no need to place two heat transfer members inside the battery pack, costs can be reduced, and the number of quality inspections required can be reduced to one, which simplifies the process and reduces process costs.

[0030] Furthermore, reducing the volume of the battery pack is advantageous for miniaturization, and it is possible to increase the capacity and output of the battery pack for the same size. [Brief description of the drawings]

[0031] [Figure 1] 1 is a perspective view of a battery pack according to an embodiment of the present invention; [Diagram 2] 2 is a cross-sectional view taken along line AA' in FIG. 1. [Diagram 3] FIG. 2 is an exploded perspective view of a battery module including a U-shaped frame. [Figure 4] FIG. 2 is an exploded perspective view of a battery module including a monoframe. [Diagram 5] FIG. 4 is a perspective view of the battery module of FIG. [Figure 6] FIG. 4 is a cross-sectional view illustrating a battery pack according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in various different forms and should not be construed as being limited to the embodiments set forth herein, but rather may be practiced in a variety of different ways.

[0033] In order to clearly describe the present invention, parts unnecessary for the description are omitted, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0034] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are enlarged to clearly show multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0035] In addition, when a part such as a layer, film, region, or plate is said to be "above" another part, this includes not only the case where it is "directly above" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly above" another part, it means that there is no other part in between. In addition, being "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" in the opposite direction to gravity.

[0036] Furthermore, throughout the specification, when a part is said to "comprise" a certain element, this does not mean that it excludes other elements and may further include other elements, unless specifically stated to the contrary.

[0037] FIG. 1 is a perspective view of a battery pack 100 according to an embodiment of the present invention.

[0038] 1, a battery pack 100 according to an embodiment of the present invention includes a battery module 200 and a pack frame 400 that houses the battery modules 200. Although six battery modules 200 are housed in Fig. 1, there is no limit to the number, and one or more battery modules 200 may be housed in the pack frame 400 as necessary.

[0039] FIG. 2 is a cross-sectional view taken along line AA' in FIG.

[0040] 2, the battery module 200 includes a cell stack 300 in which one or more battery cells 310 are stacked, and a module frame 210 that houses the cell stack 300. A thermally conductive resin layer 500 is located between a lower surface of the module frame 210 and a pack frame 400, and an opening 240 is formed on the lower surface of the module frame 210 so that the cell stack 300 can be in contact with the thermally conductive resin layer 500. In addition, a heat sink 600 can be located between the thermally conductive resin layer 500 and a bottom of the pack frame 400.

[0041] The opening 240 formed on the lower surface of the module frame 210 will be described below with reference to Figs. 3 and 4. Figs. 3 and 4 are exploded perspective views of the battery modules 200a, 200b that can be applied to an embodiment of the present invention. Specifically, Fig. 3 is an exploded perspective view of the battery module 200a including a U-shaped frame 210a, and Fig. 4 is an exploded perspective view of the battery module 200b including a monoframe 210b. For ease of explanation, Figs. 3 and 4 both show the battery modules 200a, 200b turned upside down so that the lower surfaces face upward.

[0042] The module frame 210 in FIG. 2 is a metal plate, and may be a U-shaped frame or a monoframe. The battery module 200a in FIG. 3 is a U-shaped frame, and the battery module 200b in FIG. 4 is a monoframe.

[0043] 3, the battery module 200a of the present embodiment may include a U-shaped frame 210a that houses the cell stack 300. The U-shaped frame 210a has an open top, front, and rear surface, and a cover 230 may be coupled to the open top surface, and end plates 220 may be coupled to the open front and rear surfaces.

[0044] At this time, as mentioned above, the opening 240a is formed on the lower surface of the U-shaped frame 210a, and the cell stack 300 is exposed through the opening 240a.

[0045] 4, the battery module 200b of the present embodiment may include a monoframe 210b that houses the cell stack 300. The monoframe 210b has an open front and rear surface, and end plates 220 may be coupled to the open front and rear surfaces.

[0046] Similarly, an opening 240b is formed on the lower surface of the monoframe 210b, and the cell stack 300 is exposed through the opening 240b.

[0047] 2 to 4, the cell stack 300 comes into contact with the thermally conductive resin layer 500 through openings 240, 240a, 240b formed on the bottom surface of the module frame 210, i.e., the U-shaped frame 210a or the monoframe 210b. Heat generated in the battery cells 310 of the cell stack 300 can be transferred through the thermally conductive resin layer 500 and a heat sink 600 located below the thermally conductive resin layer 500.

[0048] If the openings 240, 240a, 240b were not formed, a heat transfer member such as the thermally conductive resin layer 500 would have to be disposed twice between the cell stack 300 and the module frame 210, and between the module frame 210 and the heat sink 600. This is because air gaps between the battery cells and the battery modules and between the battery modules and the battery pack must all be eliminated in order to transfer heat.

[0049] However, in this embodiment, since the openings 240, 240a, and 240b are formed, there is no need to place two thermally conductive resin layers 500. This allows cost reduction and reduces the number of quality inspections for the interface of the heat transfer member to one, which simplifies the process and reduces the process cost.

[0050] In addition, the height of the battery pack 100 can be reduced compared to the case where two thermally conductive resin layers are arranged. Generally, when a battery pack is placed at the bottom of a vehicle, there is a large restriction on the height direction, but the battery pack 100 according to the present embodiment has an advantage that the restriction on the height can be reduced.

[0051] From another perspective, since the number of thermally conductive resin layers is reduced in a limited space, the volume of the battery cells 310 can be increased accordingly, which has the effect of improving the capacity and output of the battery pack 100.

[0052] In addition, if the openings 240, 240a, and 240b are not formed, the double heat transfer member is located between the cell stack 300 and the heat sink 600, and the module frame is located between the double heat transfer member, so that the heat generated from the battery cell 310 is not effectively transferred. This is because the module frame itself can reduce the heat conduction characteristics, and a fine air layer that can be formed between the module frame and the double heat transfer member can also be a factor in reducing the heat transfer characteristics. In contrast, the openings 240, 240a, and 240b in this embodiment can simplify the heat transfer path between the cell stack 300 and the heat sink 600 to a single thermally conductive resin layer 500, so that the cooling performance of the battery pack 100 can be improved.

[0053] This principle can also be applied in the same way when the thermally conductive resin layer 500 is in direct contact with the bottom of the pack frame 400 without the heat sink 600 being configured.

[0054] Fig. 5 is a perspective view of the battery module 200a of Fig. 3. However, unlike Fig. 3, it shows the battery module 200a in an assembled state, not turned over, with the top surface facing upward.

[0055] 5 together with FIG 3, a cover 230 is coupled to an open upper surface of a U-shaped frame 210a, and the cover 230 may have a single plate-shaped structure. The U-shaped frame 210a and the cover 230 may be coupled by welding or the like with corresponding corners in contact with each other to form a structure surrounding the cell stack 300. That is, the U-shaped frame 210a and the cover 230 may have a coupling part CP formed by a coupling method such as welding at corresponding corners.

[0056] 2 to 4, the thermally conductive resin layer 500 in the present embodiment may include a thermally conductive resin, and in particular may include a thermally conductive adhesive material, such as at least one of a silicon-based material, a urethane-based material, and an acrylic-based material, and in particular may include a urethane-based material.

[0057] Since the thermally conductive resin layer 500 contains a thermally conductive resin with excellent thermal conductivity, the amount and speed of heat transfer between the cell stack 300 and the heat sink 600 can be further increased.

[0058] In addition, the thermally conductive resin may be a material containing a thermally conductive adhesive material that is liquid when applied, but solidifies after the cell stack 300 is stacked thereon through the openings 240, 240a, 240b. Therefore, the thermally conductive resin layer 500 can fix the cell stack 300 and the battery modules 200, 200a, 200b including the cell stack 300 within the battery pack 100. In other words, the thermally conductive resin layer 500 in this embodiment not only improves the heat dissipation characteristics of the cell stack 300 through the openings 240, 240a, 240b, but also has the effect of effectively fixing the cell stack 300.

[0059] For such fixation, the thermally conductive resin layer 500 preferably has a peel strength of 400 g / cm or more when a peel strength test is performed, and preferably has an adhesive strength of 1.4 MPa or more when a shear strength test is performed.

[0060] 1 again, in order to fix the battery module 200 in the pack frame 400, a fastening structure such as a hook or a bolt may be formed at the four corners (black arrows) of the battery module 200. This is to ensure safety against vibration, impact, etc. when the battery module 200 is applied to a device described below.

[0061] However, in this embodiment, since the battery module 200 can be fixed in the battery pack 100 through the thermally conductive resin layer 500 in FIG. 2, fastening structures such as hook structures or bolts can be located at only two or one of the four corners (black arrows) of the battery module 200, and in some cases, it is also possible to fix the battery module 200 using only the thermally conductive resin layer 500 without the fastening structure.

[0062] 1 and 2, the pack frame 400 may further include a partition 410 formed between the side surfaces of the battery modules 200. When the battery pack 100 is applied to a device such as an automobile, the partition 410 may support the battery pack 100 against external impact and prevent the battery modules 200 from moving within the battery pack 100. In addition, the side surface of the battery module 200 may be in close contact with the partition 410 or may be spaced apart from it by a predetermined distance, but in order to achieve this effect, it is more preferable to form a structure in which the side surface of the battery module 200 is in close contact with the partition 410 as shown in FIG.

[0063] Meanwhile, Fig. 6 is a cross-sectional view illustrating a battery pack 100a according to another embodiment of the present invention. Referring to Fig. 6, the battery pack 100a may include a pack frame 400a without a partition wall, and a structure in which the sides of the battery modules 200 are closely attached to each other may be formed. That is, among the battery modules, the battery modules 200 arranged along the lateral direction may be closely attached to each other through their sides.

[0064] 1 and 2, the cell stack 300 of the battery module 200 is bonded to the thermally conductive resin layer 500a through an opening 240 formed on the lower surface of the module frame 210, and a heat sink 600a may be located below the thermally conductive resin layer 500a. However, since the pack frame 400a does not include a partition wall, the battery modules 200 that are in close contact along the sides as in FIG. 6 may share one thermally conductive resin layer 500a.

[0065] As mentioned above, since the thermally conductive resin layers 500, 500a in Fig. 2 and Fig. 6 can fix the cell stack 300 and the battery modules 200, 200a, 200b, a separate fastening member such as a bolt for fastening can be reduced or eliminated. Therefore, instead of the space required for fastening the bolts or nuts, a structure in which the battery module 200 is in close contact with the partition wall 410 as in Fig. 2 or a structure in which the battery modules 200 are in close contact with each other as in Fig. 6 can be formed. As a result, the battery modules 200 can be arranged compactly, which can lead to a reduction in the volume of the battery packs 100, 100a or an increase in the battery capacity.

[0066] 2, the battery cells 310 constituting the cell stack 300 are preferably stacked in an upright or inverted manner so as to be parallel to both sides of the module frame 210. In this way, each of the battery cells 310 can be exposed to the opening 240 and come into contact with the thermally conductive resin layer 500.

[0067] 3 and 4, the openings 240a and 240b may be spaced apart from the front and rear surfaces of the module frames 210a and 210b, respectively. That is, the lower surfaces of the module frames 210a and 210b where the openings 240a and 240b are not formed may be adjacent to the front and rear surfaces of the module frames 210a and 210b, respectively. If the openings 240a and 240b are formed in the entire area of ​​the lower surfaces, there may be a problem that the cell stack 300 or a part of it may come off during the manufacturing process of the battery modules 200a and 200b or the assembly process of the battery pack. Considering the stacking form and direction of the battery cells 310 mentioned above, the openings 240a and 240b are formed spaced apart from the front and rear surfaces of the module frames 210a and 210b, respectively, thereby preventing the cell stack 300 from coming off.

[0068] Meanwhile, the openings 240a, 240b may be adjacent to both side surfaces of the module frames 210a, 210b. Considering the stacking form and direction of the battery cells 310 mentioned above, only when the openings 240a, 240b are adjacent to both side surfaces of the module frames 210a, 210b can all the battery cells, including the battery cells at both ends of the cell stack 300, come into contact with the thermally conductive resin layer. Only when all the battery cells constituting the cell stack 300 come into contact with the thermally conductive resin layer can effective heat dissipation be achieved.

[0069] The battery pack described above may be applied to various devices, including, but not limited to, transportation means such as electric bicycles, electric cars, and hybrid vehicles, and may be applied to various devices that can use secondary batteries.

[0070] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the claims also fall within the scope of the present invention. [Explanation of symbols]

[0071] 100: Battery pack 200, 200a, 200b: Battery module 210: Module frame 300: Cell stack 400: Pack Frame 500: Thermally conductive resin layer 600: Heat sink

Claims

1. a battery module including a cell stack in which one or more battery cells are stacked, and a module frame that houses the cell stack; A pack frame that houses the battery module; and a thermally conductive resin layer located between the lower surface of the module frame and the pack frame; Including, an opening is formed in the lower surface of the module frame, and the cell stack is in contact with the thermally conductive resin layer; the thermally conductive resin layer is in a state where the thermally conductive resin is solidified while being in contact with the cell stack, The battery module is two or more; A battery pack in which two or more of the battery modules share one of the thermally conductive resin layers.

2. The battery pack according to claim 1 , wherein the thermally conductive resin layer includes a thermally conductive adhesive material.

3. The battery pack according to claim 1 or 2, further comprising a heat sink located between the thermally conductive resin layer and a bottom of the pack frame.

4. At least one of the module frames is a U-shaped frame; The battery pack according to claim 1 , wherein the opening is formed on a lower surface of the U-shaped frame.

5. A cover is located on the top surface of the U-shaped frame, The battery pack according to claim 4 , wherein the U-shaped frame and the cover are welded together to form a joint.

6. At least one of the module frames is a monoframe having an open front and rear surface; The battery pack according to any one of claims 1 to 3, wherein the opening is formed on a lower surface of the monoframe.

7. The battery pack according to claim 1 , wherein the battery modules arranged along a lateral direction of the battery modules are in close contact with each other at their lateral sides.

8. The one or more battery cells are stacked in an upright or inverted manner so as to be parallel to both sides of the module frame, The battery pack according to any one of claims 1 to 7, wherein each of the one or more battery cells is in contact with the thermally conductive resin layer.

9. The battery pack according to any one of claims 1 to 8, wherein the opening is spaced apart from each of a front surface and a rear surface of the module frame.

10. The battery pack according to any one of claims 1 to 9, wherein the opening is adjacent to both side surfaces of the module frame.

11. A device comprising one or more battery packs according to any one of claims 1 to 10.

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