Battery module and manufacturing method thereof

Abstract

A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked in one direction, a module frame that houses the battery cell stack, and an end plate that is coupled to the module frame and covers a front or rear surface of the battery cell stack, the module frame including a first layer and a second layer, and a melting point of the first layer is higher than a melting point of the second layer.

Description

[Technical field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority to Korean Patent Application No. 10-2021-0079379 filed on June 18, 2021, and Korean Patent Application No. 10-2022-0072785 filed on June 15, 2022, and all contents disclosed in the Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery module and a method for manufacturing the same, and more particularly to a battery module with enhanced safety and a method for manufacturing the same. [Background technology]

[0003] In modern society, the use of portable devices such as mobile phones, laptops, camcorders, and digital cameras has become commonplace, and the development of technology related to such mobile devices is becoming more and more active. In addition, rechargeable secondary batteries are being 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 problems such as air pollution caused by conventional gasoline-powered vehicles that use fossil fuels, and there is an increasing need for the development of secondary batteries.

[0004] Currently commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are in the spotlight due to their advantages of being freely chargeable and dischargeable, having a very low self-discharge rate, and having a high energy density.

[0005] Meanwhile, in the case of secondary batteries used in small devices, mainly 2-3 battery cells are used, whereas in the case of secondary batteries used in medium to large devices such as automobiles, medium to large battery modules in which multiple battery cells are electrically connected are used.

[0006] Since it is preferable for medium- to large-sized battery modules to be manufactured with small size and weight if possible, prismatic batteries, pouch-shaped batteries, etc., which can be stacked with a high degree of integration and have a small weight relative to their capacity, are mainly used as battery cells for medium- to large-sized battery modules.

[0007] The battery cells installed in the battery module generate a large amount of heat during charging and discharging, and if the temperature becomes higher than the appropriate temperature due to overcharging or other reasons, the performance will deteriorate, and if the temperature rises excessively, there is a risk of explosion or fire. If a thermal runaway phenomenon occurs in the battery module due to overcharging or other reasons, the internal temperature and internal pressure of the battery module will rise significantly, and the module frame or end plate forming the outer surface of the battery module may collapse due to the high temperature or pressure. If the sealed structure of the battery module collapses in this way, internal heat, gas, sparks, flames, etc. will be released to the outside, and the high-temperature battery cells or gases may come into contact with external oxygen, causing a chain reaction of thermal runaway phenomena.

[0008] In the past, attempts were made to solve this problem by mainly filling the inner surface of the module frame with a heat-resistant shielding structure. However, applying a heat-resistant shielding structure inside the battery module increases the manufacturing cost, complicates the manufacturing process, and further narrows the internal space of the battery module.

[0009] Therefore, there is a need for a technology that can solve such problems of the conventional technology. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a battery module having improved durability and safety by preventing continuous thermal runaway, and a manufacturing method thereof.

[0011] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0012] A battery module according to one embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked in one direction, a module frame that houses the battery cell stack, and an end plate that is coupled to the module frame and covers a front or rear surface of the battery cell stack, the module frame including a first layer and a second layer, and a melting point of the first layer is higher than a melting point of the second layer.

[0013] An interior surface of the module frame may include the first layer and an exterior surface of the module frame may include the second layer.

[0014] The module frame is a monoframe having a rectangular tubular shape so that the battery cell stack can be housed therein, and the monoframe may be formed by forming a plate material into a tubular shape and then joining two ends of the plate material.

[0015] A step portion not including the first layer may be formed in a first end of the two ends, and a second end may be bonded to the step portion of the first end.

[0016] A step portion not including the first layer may be formed at each of the two ends, and the step portions may be joined by being interlocked with each other.

[0017] The module frame may include a U-shaped frame having an open top or bottom surface, and a straight cover covering the open top or bottom surface of the U-shaped frame.

[0018] A stepped portion not including the first layer may be formed at each end of the U-shaped frame, and both ends of the straight cover may be joined to the stepped portions.

[0019] A stepped portion not including the first layer may be formed at each end of the straight cover, and both ends of the U-shaped frame may be joined to the stepped portions.

[0020] A first step portion not including the first layer may be formed at each of both ends of the U-shaped frame, and a second step portion not including the first layer may be formed at each of both ends of the straight cover, and the first step portion and the second step portion may be joined by engaging with each other.

[0021] Either the U-shaped frame or the straight cover may be entirely free of the first layer.

[0022] The module frame may include two U-shaped frames.

[0023] Both ends of the two U-shaped frames may be joined facing each other to form one side of the module frame.

[0024] Each of the two U-shaped frames may further include a flange portion extending to the outside of the module frame at both ends, the flange portion not including the first layer, and the flange portions of the two U-shaped frames may be joined to each other.

[0025] Either one of the two U-shaped frames may be entirely free of the first layer.

[0026] The first layer may have a melting point of 1000° C. or higher.

[0027] The first layer may have a lower thermal conductivity than the second layer.

[0028] The specific gravity of the first layer can be greater than the specific gravity of the second layer.

[0029] The thickness of the first layer and the thickness of the second layer can be different.

[0030] The thickness ratio of the first layer to the second layer may be from 1:5 to 1:30.

[0031] The first layer may have a thickness of 0.1 to 0.3 mm.

[0032] The second layer may have a thickness of 1.5 to 3.0 mm.

[0033] The first layer may include stainless steel and the second layer may include aluminum, gold, silver, copper, platinum, or an alloy including any of the above.

[0034] The first layer and the second layer may be bonded by atomic diffusion bonding.

[0035] At least one of the corners of the module frame may be formed through a bonding process, and the second layer of the corner may have a joint formed through the bonding process.

[0036] In another embodiment of the present invention, a method for manufacturing a battery module includes forming a module frame that accommodates a battery cell stack, and joining the module frame to an end plate, wherein forming the module frame includes cutting a metal plate, shaping the cut metal plate into a predetermined shape, partially removing one end of the metal plate, and joining one end of the metal plate, and the module frame includes a first layer and a second layer, and a melting point of the first layer is higher than a melting point of the second layer.

[0037] A battery pack according to another embodiment of the present invention includes at least one battery module as described above. Effect of the Invention

[0038] According to the embodiment, the battery module of the present invention includes a module frame capable of withstanding high temperatures and high pressures, and therefore can maintain its shape even when a fire breaks out inside the battery module, thereby preventing a chain reaction of thermal runaway.

[0039] The effects of the present invention are not limited to those 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]

[0040] [Figure 1] 1 is a perspective view showing a battery module according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an exploded perspective view of the battery module shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4a] 1 is a diagram showing a structure of a module frame according to an embodiment of the present invention. [Figure 4b] 1 is a diagram showing a structure of a module frame according to an embodiment of the present invention. [Figure 4c] 1 is a diagram showing a structure of a module frame according to an embodiment of the present invention. [Figure 4d] 1 is a diagram showing a structure of a module frame according to an embodiment of the present invention. [Figure 4e] 1 is a diagram showing a structure of a module frame according to an embodiment of the present invention. [Figure 5a] 1 is a diagram illustrating a method of manufacturing a module frame according to an embodiment of the present invention; [Figure 5b] 1 is a diagram illustrating a method of manufacturing a module frame according to an embodiment of the present invention; [Figure 6a] 11 is another view illustrating a method for manufacturing a module frame according to an embodiment of the present invention. [Figure 6b] 11 is another view illustrating a method for manufacturing a module frame according to an embodiment of the present invention. [Figure 7a] 11 is another view illustrating a method for manufacturing a module frame according to an embodiment of the present invention. [Figure 7b] 11 is another view illustrating a method for manufacturing a module frame according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of a semiconductor device according to an embodiment of the present invention;

[0042] In order to clearly describe the present invention, parts not necessary for the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0043] 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 order to clearly express multiple layers and regions in the drawings, the thicknesses are enlarged. In the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0044] In addition, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes not only the case where the layer, film, region, plate, or other part 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 "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the opposite direction of gravity. Meanwhile, just as being "on" or "above" another part, being "below" or "below" another part should also be understood with reference to the above content.

[0045] In addition, throughout the specification, when a part is said to "comprise" a certain element, this means that it may further include other elements, not excluding other elements, unless specifically stated to the contrary.

[0046] Also, throughout the specification, a reference to "in a plane" means a portion of the subject matter viewed from above, and a reference to "in cross section" means a portion of the subject matter viewed from the side along a vertical cut therethrough.

[0047] Hereinafter, a battery module according to an embodiment of the present invention will be described.

[0048] FIG. 1 is a perspective view showing a battery module according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of the battery module shown in FIG.

[0049] 1 and 2, a battery module 100 according to one embodiment of the present invention may include a battery cell stack 120 in which a plurality of battery cells 110 are stacked in one direction, a module frame 200 that houses the battery cell stack 120, and an end plate 400 that covers the front and / or rear surface of the battery cell stack 120.

[0050] The battery cells 110 according to this embodiment are provided in a pouch type that can maximize the number of cells stacked per unit area, but this is not necessarily required and they may also be provided in a rectangular or cylindrical type such as a jelly-roll configuration.

[0051] The module frame 200 according to this embodiment may be for protecting the battery cell stack 120 and electrical components connected thereto from external physical impact. The module frame 200 may accommodate the battery cell stack 120 and electrical components connected thereto in an internal space of the module frame 200. Here, the module frame 200 includes an internal surface and an external surface, and the internal space of the module frame 200 may be defined by the internal surface.

[0052] 1, the module frame 200 has two faces facing each other on the z-axis and two faces facing each other on the y-axis, the two faces facing each other on the z-axis being the top face (+z-axis direction) and the bottom face (-z-axis direction), and the two faces facing each other on the y-axis being side faces. Also, the two faces facing each other on the z-axis can be called faces on the z-axis, and the two faces facing each other on the y-axis can be called faces on the y-axis.

[0053] The end plate 400 according to the present embodiment may be for protecting the battery cell stack 120 and electrical equipment connected thereto from external physical impact by sealing the open side of the module frame 200. The structure of the module frame 200 may be provided in a hollow form that is open along the length direction of the battery cell stack 120, and the front and rear sides of the battery cell stack 120 may not be covered by the module frame 200. The front and rear sides of the battery cell stack 120 are covered by the end plate 400, etc., so that the front and rear sides of the battery cell stack 120 can be protected from external physical impact, etc. For this purpose, the end plate 400 may be manufactured from a material having a predetermined strength. For example, the end plate 400 may include a metal such as aluminum.

[0054] Meanwhile, the module frame 200 may be mainly manufactured from a metal having high thermal conductivity for heat dissipation of the battery module 100, and examples of the metal used for the module frame 200 may include aluminum, gold, silver, copper, platinum, or alloys containing these metals.

[0055] Such metals are mainly used as materials for the module frame 200 because they have excellent thermal conductivity while satisfying the rigidity level required by the battery module 100, but there is a problem that the shape of the battery module 100 may collapse and promote thermal runaway when an internal fire occurs in the battery module 100. Specifically, when a thermal runaway phenomenon occurs inside the battery module 100, the internal temperature may be 1000°C or 1200°C or higher, while the melting point of aluminum is at the 660°C level, making it difficult for the external shape of the battery module 100 to be maintained when an internal fire occurs.

[0056] In order to improve the heat resistance of the module frame 200, it is possible to manufacture the module frame 200 from steel or stainless steel having a melting point of 1400° C. or more. However, if the module frame 200 is manufactured from steel, not only will the weight of the module frame 200 increase, making it impossible to achieve a reduction in the weight of the battery module 100, but there is also a problem that the heat dissipation performance of the battery module 100 will decrease because the thermal conductivity of steel is lower than that of aluminum, etc.

[0057] Therefore, the following describes a module frame herein that is devised to solve the problems discussed above.

[0058] FIG. 3 is a cross-sectional view of one embodiment taken along line AA in FIG.

[0059] Referring to the AA cross section of the module frame 200 shown in Fig. 3, the module frame 200 of this embodiment may include a first layer 210 and a second layer 220. The first layer 210 may be laminated on one side of the second layer 220. The second layer 220 may be laminated on one side of the first layer 210. The present invention is not limited to what is shown in Fig. 3, and includes cases where a portion of the module frame 200 includes any one of the first layer 210 and the second layer 220.

[0060] When the direction from the inner surface of the module frame 200 to the outer surface is referred to as a first direction, the second layer 220 can be located in the first direction of the first layer 210. When the direction from the outer surface of the module frame 200 to the inner surface is referred to as a second direction, the first layer 210 can be located in the second direction of the second layer 220. In the module frame 200, the first layer 210 can be located closer to the inner surface of the module frame 200 than the second layer 220, and the second layer 220 can be located closer to the outer surface of the module frame 200 than the first layer 210. The second layer 220 can be located outside the first layer 210. In the module frame 200, the first layer 210 can form the inner surface of the module frame 200, and the second layer 220 can form the outer surface of the module frame 200.

[0061] The first layer 210 and the second layer 220 included in the module frame 200 may have different physical properties. For example, the first layer 210 may be made of a material having a higher heat resistance than the second layer 220. If the first layer 210 is made of a material having a higher heat resistance, the battery module 100 can maintain its shape even in the event of internal ignition, thereby preventing the collapse of the module frame 200 from causing oxygen to flow into the battery module 100 or from transmitting gas or sparks to other battery modules 100. Therefore, when considering internal ignition of the battery module 100, it may be preferable that the first layer 210, which is made of a material having a higher heat resistance, forms an inner surface of the battery module 100 or is located close to the inner surface. As another example, the second layer 220 may be made of a material having a lower unit weight or specific gravity than the first layer 210, thereby allowing the overall weight of the module frame 200 to be somewhat reduced. In addition, the second layer 220 is made of a material having a higher thermal conductivity than the first layer 210, thereby complementing the heat dissipation performance of the module frame 200.

[0062] The first layer 210 of the module frame 200 may be manufactured from a material having a higher melting point than the second layer 220. The first layer 210 of the module frame 200 may include a material that maintains its shape even at a temperature of 1000°C or 1200°C. The first layer 210 of the module frame 200 may include a material that maintains its shape even at a pressure of 2 bar or more. The first layer 210 provided from a material that maintains its shape even in a high temperature and high pressure environment may preferably form an inner surface of the battery module 100 or be located close to the inner surface. As a specific example, the first layer 210 may include stainless steel. As a specific example, the first layer 210 may include STS4xx, STS304, STS316, or other steel systems.

[0063] The thickness of the first layer 210 of the module frame 200 may be 0.1 to 0.3 mm. If the thickness of the first layer 210 is less than 0.1 mm, it may be difficult to ensure the heat resistance of the module frame 200. If the thickness of the first layer 210 is more than 0.3 mm, the overall weight of the module frame 200 may increase, and the overall thermal conductivity of the module frame 200 may be somewhat reduced. In addition, if the manufacturing cost of the first layer 210 is somewhat high, a problem of an increase in the manufacturing cost of the module frame 200 due to the increase in the thickness value of the first layer 210 may occur.

[0064] The second layer 220 of the module frame 200 can be made of a material having a higher thermal conductivity than the first layer 210. The thermal conductivity of the second layer 220 can vary depending on its thickness, but can be 20 W / mk, 50 W / mk, 100 W / mk, or 150 W / mk or more.

[0065] The second layer 220 of the module frame 200 may be manufactured from a lighter material having a lower unit weight, i.e., specific gravity, than the first layer 210. For example, the second layer 220 may include aluminum, gold, silver, copper, platinum, or an alloy including these. As a specific example, the second layer 220 may include A3xxx, A5xxx, A6xxx, or other aluminum. Since the specific gravity of aluminum is about 2.7, the difference may be about 1 / 3 of that of steel, which has a specific gravity of 7.7 or more.

[0066] The thickness of the second layer 220 of the module frame 200 may be 1.5 to 3.0 mm. If the thickness of the second layer 220 is less than 1.5 mm, it is difficult to ensure the overall rigidity of the module frame 200, and if the thickness is more than 3.0 mm, the overall thickness of the module frame 200 may increase more than necessary.

[0067] As described above, the module frame 200 of the present embodiment may have improved heat resistance or corrosion resistance, etc., by further including the first layer 210, compared to a module frame 200 having only the second layer 220. In this case, if the first layer 210 forms an inner surface of the module frame 200 or is located close to the inner surface, the effect of the first layer 210 may be more pronounced. In addition, the module frame 200 of the present embodiment may have a reduced specific gravity and improved thermal conductivity, thereby reducing the overall manufacturing cost, by further including the second layer 220, compared to a module frame 200 having only the first layer 210. In addition, as described above, the rigidity and heat resistance of the module frame 200 are improved, and therefore the battery module 100 of the present embodiment may be able to minimize the use of additional heat-resistant members, and may not require a separate heat-resistant structure.

[0068] Meanwhile, in the above description, the module frame 200 has been described based on having two layers, but this is not necessarily the case, and the module frame 200 may be provided as having three or more layers. Thus, the first layer 210 and the second layer 220 may be combined without another layer interposed between the two layers, but this is not necessarily the case, and the first layer 210 and the second layer 220 may be combined to include another layer interposed between the two layers. Also, another layer located in a first direction or a second direction of the first layer 210 or the second layer 220 may be further added to the first layer 210 or the second layer 220.

[0069] In addition, although the above description has been given on the basis that two layers are provided entirely in module frame 200, such description does not exclude the module frame 200 being partially provided with two layers, and it should be construed that the module frame 200 partially including two layers is also included in the content of the present invention. As will be described later, when module frame 200 is formed by combining a plurality of sub-frames, only some of the plurality of sub-frames may be manufactured from a material having two layers, and the remaining of the plurality of sub-frames may be manufactured from a material having a single layer.

[0070] The module frame 200 of this embodiment may be manufactured from a clad metal material including a first layer 210 and a second layer 220. Clad metal may be a common name for a material in which a metal or non-ferrous metal layer is used as a base layer and another metal or non-ferrous metal material is bonded to one or both sides of the base layer in order to add new properties that the base material does not have. By bonding two types of metals with different physical properties, the advantages of each are maintained and the disadvantages of each are complemented, so the function of the clad metal can be improved beyond the functions of each metal.

[0071] Clad metals can be formed by methods such as welding, rolling, casting, extrusion, etc. Clad metals can include at least two metal layers, which are bonded by atomic diffusion bonding, and therefore may be less likely to peel off than layers bonded via adhesives, etc. In addition, in the case of dissimilar metals bonded through clad metals, the two metal layers do not peel off sufficiently even when bending or an external force is applied, and the bonding strength can be further improved over time.

[0072] Meanwhile, a coating process may be used to manufacture a module frame 200 including two metals having different physical properties. Specifically, the module frame 200 including two layers may be manufactured by coating the inner surface of the module frame 200 formed on the material of the second layer 220 with the material of the first layer 210. However, considering the narrow inner space of the module frame 200, coating the inner surface of the module frame 200 is not only difficult, but also difficult to form a uniform coating layer even if possible. In addition, since various components including the battery cell stack 120 are disposed in the inner space of the module frame 200, the coating layer may be damaged during the process of inserting these components into the module frame 200. When manufacturing the module frame 200 including two layers through a coating process, cracks may occur during the process of forming the coating layer or during the process of inserting other components into the inner space of the module frame 200 after the coating layer is formed. In the event of an internal fire in the battery module 100, heat or pressure may be transferred through such cracks to the outer layer, i.e., the second layer 220, of the module frame 200, which may cause the module frame 200 to collapse. Therefore, it is difficult to ensure the durability of the module frame 200 manufactured through a coating process.

[0073] FIG. 4 is a diagram showing the structure of a module frame according to an embodiment of the present invention.

[0074] With reference to the cross-section of module frame 200 shown in FIG. 4, the configuration of module frame 200 can vary.

[0075] As an example, the module frame 200 may be a roll-press type monoframe 200a as shown in FIG. 4a. A metal plate cut to accommodate the battery cell stack therein may be formed into a hollow rectangular tube shape, and both ends 202a of the adjacent metal plate may be joined vertically. As another example, the module frame 200 may be provided in a structure in which a U-shaped frame 200b-1 with an open front, rear, and top surface and a straight-shaped upper frame 200b-2 are combined as shown in FIG. 4b. The U-shaped frame may be formed by forming a metal plate into a U-shape through a molding process. The U-shaped frame 200b-1 has a lower surface (bottom surface) and both side surfaces, and may be combined with the upper frame 200b-2 to cover the open top surface of the U-shaped frame. The U-shaped frame 200b-1 and the upper frame 200b-2 may be combined by a joining process with the corresponding ends 202b-1, 202b-2 in vertical contact with each other. Also, as the opposite case to FIG. 4b, a structure may be provided in which a U-shaped frame with an open front, rear, and lower surface (bottom surface) is combined with a one-sided lower frame. Similarly, the U-shaped frame and the lower frame may be combined by a joining process with the corresponding ends in vertical contact with each other. For convenience, the drawings are omitted, and other matters may be described in the same manner with the top-bottom symmetrical drawing of FIG. 4b.

[0076] As another example, the module frame 200 may have a structure in which two U-shaped frames 200c are combined as shown in Fig. 4c. Flange portions 204c may be formed at both ends 202c of the two U-shaped frames 200c, and the two U-shaped frames 200c may be combined by joining the flange portions 204c. That is, the flange portions on both sides of the upper U-shaped frame and the flange portions 204c on both sides of the lower U-shaped frame may be combined by a joining process while facing and contacting each other. The flange portions of the upper U-shaped frame and the flange portions of the lower U-shaped frame may have the same length or may be different from each other. The flange portion 204c may not include a first layer.

[0077] Similarly, in Fig. 4d, two U-shaped frames 200d may be joined together. Unlike Fig. 4c, Fig. 4d does not include a flange portion, and two U-shaped frames 200d may be joined together by a joining process in a state where both ends 202d of the frames face each other and are in contact with each other. That is, both ends of the upper U-shaped frame and the corresponding ends of the lower U-shaped frame may be joined together by a joining process in a state where both ends face each other and are in contact with each other. Thus, the corresponding ends 202d of the upper U-shaped frame and the lower U-shaped frame may be positioned on one surface of the module frame 200, and the joint surface formed by joining the corresponding ends 202d may also be positioned on one surface of the rectangular tube shape.

[0078] 4e, the module frame 200 may be a roll-press type monoframe 200e. A cut metal plate may be formed into a hollow rectangular tube shape so that the battery cell stack can be housed therein, and both ends of the adjacent metal plate may be joined. In this case, the two ends of the formed metal plate may be located on one side of the rectangular tube shape, and a joint surface formed by joining the two ends may also be located on one side of the rectangular tube shape.

[0079] The structure of the module frame 200 can be provided in various shapes other than the above-mentioned examples, and can also be provided in an L-shaped frame structure or various structures not described.

[0080] Here, the forming process may use any conventional method and device that can form the metal plate into a tube shape or U-shape, one example of which is a pressing process. Also, the joining may be performed by any conventional method that can firmly maintain the joined state, one example of which is laser welding, plasma welding, TIG welding, etc. In the structure of each module frame 200 shown in Figure 4, the joining positions are indicated as 'welded'. Although the welded portions (welds) are shown to have gaps in Figure 4, after joining by welding, the module frame has the same shape as Figure 3.

[0081] In addition, here, when the module frame 200 is formed by combining two or more subframes as shown in Fig. 4b, Fig. 4c, and Fig. 4d, the subframes may all be manufactured from metal plate materials having two or more layers as shown in Fig. 7a, but this is not necessarily the case. At least one of the subframes may be manufactured from a metal plate material having two or more layers, and the remaining subframes may be manufactured from a metal plate material having a single layer as shown in Fig. 7b. Fig. 7b shows a case where the single-layer plate material shown on the left side is composed of the second layer 220, and the two-layer plate material shown on the right side has a thickness of the second layer 220 greater than the thickness of the first layer 210. However, the present invention is not limited thereto, and a case where the single-layer plate material is composed of the first layer 210, and the two-layer plate material has a thickness of the first layer 210 greater than the thickness of the second layer 220 is also possible.

[0082] Meanwhile, when manufacturing the module frame 200 in the shape shown in Fig. 4, it may be somewhat difficult to join metal materials having multiple layers with different physical properties. Since all metals with different melting points are exposed on the cross section of the metal plate, it may be difficult to completely bond each layer present at the two ends when joining the two ends using a welding process, which is a common joining method. Therefore, when manufacturing the module frame 200 of this embodiment, it may be preferable to perform the joining process after removing at least one layer among the multiple layers present at the two ends.

[0083] More specifically, referring to Figs. 4a, 4b, 5a and 5b, when two ends of one or two metal plates form a corner, the first layer 210 and the second layer 220 located at each end are in contact with each other perpendicularly, so one of the first layer 210 or the second layer 220 having different physical properties is removed and joined. Fig. 5 is a diagram for explaining a method for manufacturing a module frame according to an embodiment of the present invention. Referring to Figs. 5a and 5b, one corner of the module frame 200 may be formed by joining two ends located at the ends of the metal plate or the subframe. Here, at least one of the two ends to be joined together through the joining process may be partially removed, and then joined to the other end to form one corner of the module frame 200. In this case, the corner portion may be formed by joining a corner portion of one surface on the z-axis and a corner portion of one surface on the y-axis, and the module frame 200 of FIG. 4a includes at least one corner portion formed by the above-mentioned joining, and the module frame 200 of FIG. 4b includes at least two corner portions formed by the above-mentioned joining.

[0084] 5a, a step portion 230 is formed by removing a first layer 210 from one of two ends of a metal plate, and the other end is joined to the step portion 230 of the one end. Also, a case is shown in which the second layers 220 of the two ends of the metal plate are joined to each other.

[0085] 5b, a step portion 230 is formed by removing the first layer 210 at each of two ends of the metal plate, and the step portion 230 at one end is joined to the step portion 230 at the other end. Also, the embodiment of FIG. 5b shows a case where the second layers 220 at the two ends of the metal plate are joined to each other.

[0086] Specifically, in manufacturing the module frame 200, when two ends of a metal plate or metal frame are joined together, the layers of the two ends are arranged perpendicular to each other, so that the first layer 210 of one of the two ends may have to be joined to both the first layer 210 and the second layer 220 of the other end. In addition, when heat is applied to the first layer 210 and the second layer 220 for joining between them, the first layer 210 and the second layer 220 melt together, and a compound between the materials forming each layer is precipitated, which may make it difficult to form a joint surface. For example, if the first layer 210 contains Fe and the second layer 220 contains Al, the precipitated compound may be an Al-Fe compound.

[0087] However, as shown in Fig. 5a, when at least one of the first layers 210 of the two ends is removed, the second layers 220 of the ends come into contact with each other, and the two ends can be relatively easily bonded by bonding the second layer 220, which has a relatively low melting point. At this time, a step portion can be formed at one of the two ends by removing the first layer 210, and the positions of the two ends are fixed through the step portion, making the subsequent bonding process easier. In Fig. 5, not only the first layer 210 but also the second layer 220 is shown to be removed to some extent, but this is not necessarily the case, and the removed portion can be designed differently depending on the appropriate size of the step portion and various process reasons.

[0088] Here, the bonding process for bonding the two ends may be performed at a position where the second layers 220 of the two ends contact each other. A heat source such as a laser beam is provided to bond the two ends, and the direction of providing the heat source may be parallel to the bonding surface where the two ends contact. Also, the direction of providing the heat source may be a direction that forms a first angle with the bonding surface where the two ends contact. Here, the first angle may be 30 degrees or less, or 15 degrees to 30 degrees or less. The bonding surface may be formed between the second layers 220 of the two ends. Specifically, the bonding surface may be formed by contacting the second layer 220 exposed at one cross section of the two ends with the second layer 220 of the other end exposed through the removal process. The parts of the module frame 200 that are bonded to each other by being melted by the heat source may be referred to as a bonding portion. The bonding portion may be formed in the second layer 220. The bonding portion may be formed at a step portion. The bonding portion may have a shape in which a radial cross section is reduced along the direction of providing the heat source. The cross-sectional shape of the joint on its axis is shown as "Joint" in FIG.

[0089] Meanwhile, in the above, the description has been focused on removing the first layer 210 from one of the two contacting ends when forming the module frame 200 structure and then bonding them together, but this also applies to the case where the first layer 210 is removed from both ends and then bonded together as shown in Fig. 5b. Fig. 6 is another view for explaining a method of manufacturing a module frame according to an embodiment of the present invention.

[0090] Referring to FIG. 6, the module frame 200 may be formed by coupling flange portions 204c included in two U-shaped frames as shown in FIG. 4c.

[0091] Specifically, when two flanges 204c are bonded to each other for manufacturing the module frame 200, the two flanges 204c may be arranged such that the first layers 210 located on the inner surfaces are in contact with each other. In order to bond the two flanges 204c, a heat source must be applied to the first layer 210 through the second layer 220 located on the outer surface, but it may be very difficult to bond the first layers 210 having different melting points through the second layer 220. In addition, when a heat source is applied to a metal plate having two layers, the first layer 210 and the second layer 220 melt together, causing a compound between the materials forming each layer to precipitate, which may make it difficult to form a bonding surface.

[0092] However, as shown in FIG. 6, when the first layer 210 of the two flange portions 204c is removed, the second layer 220 comes into contact with each other, so that the two flange portions 204c can be relatively easily joined through a bonding process of the second layer 220.

[0093] Here, the bonding process can be performed at the portion where the second layer 220 contacts. Referring to Fig. 6a, the flanges 204c of the opposing U-shaped frames may have different lengths. In this case, the heat source may be provided in a direction that forms an acute angle with the direction from one flange to the other flange. Also, referring to Fig. 6b, the flanges 204c of the opposing U-shaped frames may have the same length. In this case, the heat source such as a laser beam used in the bonding process may be provided in a direction from one flange to the other flange.

[0094] The joint surface may be formed between the second layer 220 of the two flange portions 204c. The joint may be formed in the second layer 220. The shape of the joint may vary depending on the direction of application of the heat source, specifically the joint may have a shape with a reduced radial cross section along the direction of application of the heat source. The axial cross-sectional shape of the joint is indicated as "Joint" in FIG. 6.

[0095] 5 and 6, the first layer 210 is formed on the inner surface of the end or flange of the metal plate, but depending on the design, the end or flange of the metal plate may include three or more layers, and may further include at least one additional layer located in the first or second direction of the first layer 210 in addition to the second layer 220. In such a case, the above-mentioned removal process should be appropriately performed to remove only the first layer 210, or to remove not only the first layer 210 but also at least one of the above-mentioned additional layers, taking into consideration the melting point or position of the additional layer.

[0096] FIG. 7 is another view for explaining the method of manufacturing a module frame according to an embodiment of the present invention.

[0097] Referring again to Fig. 4d and Fig. 4e, two ends of the metal plate may be joined to form one surface. That is, the two ends are joined by facing each other's cross sections on the same plane. At this time, the first layer 210 of one end of the two ends of the metal plate may be joined to the first layer 210 of the other end, and the second layer 220 of one end may be joined to the second layer 220 of the other end. Therefore, even without the removal process described in Fig. 5 and Fig. 6, the two ends of the metal plate may be joined through a joining process as shown in Fig. 7a. Here, the joining of the two ends may be formed by joining the second layers 220 located at each end.

[0098] Here, the ends of the metal plates to be joined together may each have two layers as shown in Fig. 7a, or one may have one layer and the other two layers as shown in Fig. 7b. In this way, even when at least one of the two ends is formed of a single layer, the two ends can be joined by joining the second layer 220 where the two ends contact each other.

[0099] In addition, in Figures 4a and 4d, when a single metal plate is bent to form a hollow rectangular tube shape, the bent portion (i.e., the corner of the module frame) may be bent in a round shape or at a right angle. Similarly, when the U-shaped frames in Figures 4b, 4c, and 4e are formed by bending a single metal plate into a U shape, the bent portion (i.e., the corner of the module frame) may be bent in a round shape or at a right angle.

[0100] Hereinafter, a method for manufacturing a battery module according to an embodiment of the present invention will be described.

[0101] The manufacturing method (S1000) of the battery module 100 according to this embodiment includes the following steps: forming a module frame 200 to house the battery cell stack 120 (S1100); and The method may include a step of coupling the module frame 200 and the end plate 400 (S1200).

[0102] Here, the step (S1100) of forming the module frame 200 to accommodate the battery cell stack 120 may include a step of forming the module frame 200 and a step of mounting the battery cell stack 120 on the module frame 200, or these steps may be performed simultaneously. Specifically, when the module frame 200 is formed by combining a plurality of sub-frames, the step (S1100) of forming the module frame 200 to accommodate the battery cell stack 120 may include a step of providing one frame, a step of mounting the battery cell stack on the one frame, and a step of forming the module frame 200 by combining the one frame with another frame.

[0103] A method for manufacturing a module frame according to an embodiment of the present invention will now be described.

[0104] The manufacturing method (S2000) of the module frame 200 according to this embodiment includes the following steps: A step of cutting the metal plate material (S2100); A step of forming the cut metal plate into a predetermined shape (S2200); forming a step portion by removing a portion of an edge of the metal plate (S2300); and The method may further include joining the ends of the metal plates (S2400).

[0105] Here, when the module frame 200 is formed in the manner shown in FIG. 7, the step S2300 may be omitted.

[0106] Hereinafter, a method for manufacturing a module frame 200 (S2000) according to this embodiment will be described with reference to Fig. 4. The contents described below may include all of the contents of Figs. 3 to 7 described above, and may be more specifically understood through the above description.

[0107] For example, in the case of the module frame 200 of FIG. 4a, a metal plate is cut to a predetermined size and shape (S2100), and the cut metal plate can be formed into a rectangular tube shape (S2200). By forming the metal plate into a tube shape, the module frame 200 can have a bottom surface, two side surfaces facing each other, and a top surface. Meanwhile, by forming the metal plate into a tube shape, two ends 202a of the metal plate can be in contact with each other, and by joining them, a roll press type module frame 200a can be formed. At this time, as described in FIG. 5, at least one of the two ends 202a can be partially removed in order to easily connect the two ends 202a (S2300). At least one of the two ends 202a has a step 230 formed through a removal process, whereby the first layer 210 is partially removed, and the second layers 220 of the two ends 202a can contact each other, and the two ends 202a can be joined through step (S2400). Here, a heat source can be provided in the joining process in step (S2400) of joining one end and the other end of a metal plate. The heat source used in the joining process is provided mainly in a direction parallel to the joining surfaces of the two ends or in a direction forming an acute angle with the joining surfaces, and the shape of the joint can be determined accordingly.

[0108] As another example, in the case of the module frame 200 of Fig. 4b, a metal plate material is cut into a predetermined size and shape so as to manufacture the U-shaped frame 200b-1 and the straight frame 200b-2, respectively (S2100), and one of the cut metal plates may be formed into a U-shape (S2200). A U-shaped frame having either a lower surface or an upper surface and both side surfaces may be formed by forming the metal plate material, and a hollow module frame 200 may be formed by combining both ends of the U-shaped frame 200b-1 and both ends of the flat straight frame 200b-2. Specifically, ends 202b-1 of the two side surfaces of the U-shaped frame 200b-1 may be combined with ends 202b-2 on the y-axis of the flat upper frame 200b-2. As described above, at least one of the end 202b-1 of the U-shaped frame and the end 202b-2 of the flat upper frame is partially removed (S2300), so that the second layers 220 present at each end can contact each other. By joining one end of one metal plate to one end of another metal plate (S2400), the second layers 220 at each end can be bonded to each other. At this time, through the removal process (S2300), a step portion can be formed in at least one of the end of the U-shaped frame and the end of the flat upper frame.

[0109] As another example, in the case of the module frame 200 of Fig. 4c, a metal plate material is cut into a predetermined size and shape (S2100), and the cut metal plate material may be formed into two U-shaped frames (S2200). The U-shaped frame 200c has a bottom surface and both sides, and the module frame 200 may be formed by combining the two U-shaped frames 200c. At this time, flange portions 204c may be formed at both ends 202c of the U-shaped frame, specifically, at the ends 202c of both sides, and the two U-shaped frames may be combined by joining the flange portions 204c to each other. The flange portions 204c may be a portion extending vertically from one surface, i.e., a side surface, of the U-shaped frame. The flanges 204c located on the two U-shaped frames are arranged so that the first layers 210 face each other, and the second layers 220 come into contact with each other through the step of removing the first layers 210 (S2300), and can be joined through the step of joining one end of one metal plate to one end of another metal plate (S2400). At this time, a heat source can be provided for use in the joining process in the step (S2400). The heat source can be provided in a direction from one flange to the other flange or at an acute angle thereto, and the shape of the joining portion can be determined accordingly.

[0110] In the case of the module frame 200 of Fig. 4d, refer to the description of Fig. 4c, and instead of the flange portion 204c of Fig. 4c, both ends 202d of two U-shaped frames 200d of Fig. 4d can be joined to form the module frame 200. In the case of the module frame 200 of Fig. 4e, refer to the description of Fig. 4a, and two ends 202e of the metal plate material are joined facing each other on one side of the module frame 200.

[0111] Meanwhile, the metal plate material described above may include at least two layers, and may include the above-mentioned first layer 210 and second layer 220. In addition, the metal plate material including at least two layers may be a multi-joint metal plate material manufactured by a cladding method.

[0112] On the other hand, when two or more subframes are combined to form the module frame 200 as shown in Figures 4b, 4c, and 4d, some of the subframes may be provided as multi-joint metal plates, and the remaining subframes may be provided as a single metal plate. In this case, the single metal plate may be composed of only the second layer 220. In this case, the portion removed in step S2300 may be the first layer 210 formed at one end of the multi-joint metal plate, and the second layer 220 exposed through the removal process of the first layer 210 may come into contact with the single metal plate, and the two ends that come into contact with each other may be combined in step S2400.

[0113] Meanwhile, the above-mentioned battery module 100 may be included in a battery pack. The battery pack may include one or more battery modules according to the present embodiment, and may further include a battery management system (BMS) for managing the temperature and voltage of the battery, a cooling device, and the like.

[0114] The battery module and the battery pack including the same can be applied to various devices, including vehicles such as electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto, and the battery module and the battery pack including the same can be applied to various devices that can use the battery module, and these are also within the scope of the present invention.

[0115] 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]

[0116] 100 Battery Module 110 Battery Cell 120 Battery cell stack 200 module frame 210 1st layer 220 2nd layer 230 Step 300 Busbar Frame 400 End Plate

Claims

1. a battery cell stack in which a plurality of battery cells are stacked in one direction; a module frame that houses the battery cell stack; and an end plate coupled to the module frame and covering a front surface or a rear surface of the battery cell stack; the modular frame includes a first layer and a second layer; the melting point of the first layer is greater than the melting point of the second layer; an interior surface of the module frame including the first layer and an exterior surface of the module frame including the second layer; the first layer comprises stainless steel and the second layer comprises aluminum, gold, silver, copper, platinum, or an alloy including any of these; The module frame is bonded by atomic diffusion bonding.

2. 2. The battery module according to claim 1, wherein the module frame is a monoframe having a rectangular tubular shape so that the battery cell stack can be housed therein, and the monoframe is formed by forming a plate material into a tubular shape and then joining two ends of the plate material.

3. The battery module according to claim 2 , wherein a step portion not including the first layer is formed in a first end of the two ends, and a second end is joined to the step portion of the first end.

4. The battery module according to claim 2 , wherein a step portion not including the first layer is formed at each of the two ends, and the step portions are joined by meshing with each other.

5. The battery module of claim 1 , wherein the module frame comprises a U-shaped frame having an open upper or lower surface, and a line-shaped cover covering the open upper or lower surface of the U-shaped frame.

6. a step portion not including the first layer is formed at each of both ends of the U-shaped frame, The battery module according to claim 5 , wherein both ends of the line-shaped cover are joined to the step portions.

7. a step portion not including the first layer is formed at each of both ends of the line-shaped cover, The battery module according to claim 5 , wherein both ends of the U-shaped frame are joined to the step portions.

8. a first step portion not including the first layer is formed at each of both ends of the U-shaped frame, a second step portion not including the first layer is formed at each of both ends of the line-shaped cover, The battery module according to claim 5 , wherein the first step portion and the second step portion are joined by meshing with each other.

9. The battery module of claim 5 , wherein one of the U-shaped frame and the line-shaped cover does not entirely include the first layer.

10. The battery module according to claim 1 , wherein the module frame comprises two U-shaped frames.

11. The battery module according to claim 10 , wherein both ends of the two U-shaped frames are joined to face each other to form one surface of the module frame.

12. each of the two U-shaped frames further includes a flange portion extending to the outside of the module frame; the flange portion does not include the first layer, The battery module according to claim 10 , wherein the flange portions of the two U-shaped frames are joined to each other.

13. The battery module of claim 10 , wherein one of the two U-shaped frames does not entirely include the first layer.

14. The battery module according to claim 1 , wherein the first layer has a melting point of 1000° C. or higher.

15. The battery module according to claim 1 , wherein the first layer has a lower thermal conductivity than the second layer.

16. The battery module according to claim 1 , wherein the specific gravity of the first layer is greater than the specific gravity of the second layer.

17. The battery module according to claim 1 , wherein the first layer and the second layer have different thicknesses.

18. 2. The battery module of claim 1, wherein a thickness ratio of the first layer to the second layer is from 1:5 to 1:

30.

19. The battery module according to claim 1 , wherein the first layer has a thickness of 0.1 to 0.3 mm.

20. The battery module according to claim 1 , wherein the second layer has a thickness of 1.5 to 3.0 mm.

21. The battery module according to claim 1 , wherein at least one of the corners of the module frame is formed through a bonding process, and the second layer of the corner has a joint formed through the bonding process.

22. forming a module frame to house the battery cell stack; and A method for manufacturing a battery module, comprising the step of: coupling the module frame and an end plate, The step of forming the module frame comprises: cutting the metal sheet material; forming the cut metal plate into a predetermined shape; partially removing one end of the metal plate; and joining one end of the metal plate to another end of the metal plate or one end of another metal plate; the module frame includes a first layer and a second layer, the melting point of the first layer being greater than the melting point of the second layer; an interior surface of the module frame including the first layer and an exterior surface of the module frame including the second layer; the first layer comprises stainless steel and the second layer comprises aluminum, gold, silver, copper, platinum, or an alloy including any of these; The method for manufacturing a battery module, wherein the module frame is bonded by atomic diffusion bonding.

23. A battery pack comprising at least one battery module according to claim 1.

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