Extruded pack housing and manufacturing method thereof

Abstract

The present invention relates to a pack housing comprising: a heat sink; a pair of side frames coupled to both side surfaces of the heat sink; and a front frame and a rear frame, which are coupled to the front and rear of the heat sink. In one example, the heat sink and the pair of side frames are formed as a single body by extrusion molding, and thus bonding surfaces are not formed between the heat sink and the pair of side frames.

Description

Extruded pack housing and manufacturing method thereof

[0001] The present invention relates to a technology for manufacturing a pack housing constituting a battery pack by extrusion molding.

[0002] This application claims the benefit of priority from Republic of Korea Patent Application No. 10-2024-0038941, filed March 21, 2024, the entire contents of which are incorporated herein by reference.

[0003] Unlike primary batteries, secondary batteries are rechargeable and, due to their potential for miniaturization and large capacity, have been the subject of extensive research and development in recent years. With increasing technological development and demand for mobile devices, and the emergence of electric vehicles and energy storage systems in response to the era's growing environmental concerns, demand for secondary batteries as an energy source is rapidly increasing.

[0004] Secondary batteries are classified into coin-shaped, cylindrical, square, and pouch-shaped batteries, depending on the shape of their battery cases. In secondary batteries, the electrode assembly mounted inside the battery case is a rechargeable, power-generating element comprised of a laminated structure of electrodes and a separator.

[0005] Because secondary batteries require continuous, long-term use, effective control of the heat generated during charging and discharging is essential. If secondary batteries are not properly cooled, a temperature rise triggers an increase in current, which in turn triggers a temperature rise, resulting in a positive feedback loop, ultimately leading to a catastrophic condition known as thermal runaway.

[0006] To effectively dissipate heat generated by secondary batteries, heat sinks (also called cooling plates) with circulating coolant are widely used. These heat sinks are mounted on the underside of a battery pack containing multiple secondary batteries, for example. They perform a cooling function by absorbing heat generated within the pack through coolant and dissipating it to the outside.

[0007] Heat sinks can be categorized into brazed and extruded heat sinks based on their structure and manufacturing method. Brazed heat sinks, which form a flow path by brazing two plates, offer a high degree of freedom in flow path design. However, they suffer from reduced structural rigidity due to the deterioration of the material properties. In contrast, extruded heat sinks, manufactured as a continuous body via extrusion, offer advantages in structural rigidity. However, they only allow for straight flow paths, resulting in a large number of ports and the need for pipes for connection, which takes up space.

[0008] Extruded heat sinks are increasingly being applied due to their advantages of superior structural rigidity and durability. However, forming a pack housing using an extruded heat sink requires multiple welding processes. In other words, if each component of the pack housing, including the heat sink, is manufactured through an extrusion process to form the pack housing, the size of the extruded components is affected by the mold, and the manufacturing of the extruded housing involves a process of welding multiple components. For example, as exemplarily illustrated in Fig. 1, a multi-step welding process can be performed, in which the outside of the bottom surface of the center frame and side frames, including the heat sink, are joined by laser welding, the inside of the bottom surface is subjected to friction stir welding (FSW), and the front and rear frames are joined by cold metal transfer (CMT) welding.

[0009] When multiple welding processes are performed to manufacture a pack housing in this way, the welding process takes a lot of time and costs, and warping occurs during multiple welding processes, making it difficult to manage the dimensions of the pack housing.

[0010] The purpose of the present invention is to provide a structure of a jointed pack housing and a manufacturing method thereof for manufacturing an extruded pack housing more efficiently.

[0011] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0012] The present invention relates to a pack housing comprising a heat sink, a pair of side frames coupled to both sides of the heat sink, and a front frame and a rear frame coupled to the front and rear of the heat sink, wherein in one example, the heat sink and the pair of side frames are integrally formed by extrusion molding, so that no separate bonding surface is formed between the heat sink and the pair of side frames.

[0013] The above front frame and rear frame are welded to the above heat sink.

[0014] In one embodiment, the pack housing has a center frame parallel to the pair of side frames in the central region of the heat sink, and the heat sink and the center frame are integrally formed by extrusion molding, so that no separate bonding surface is formed between the heat sink and the center frame.

[0015] The above heat sink includes a plurality of ribs spaced apart from each other inside the heat sink along a direction parallel to the pair of side frames, and a hollow passage can be formed between the plurality of ribs.

[0016] Meanwhile, the present invention provides a method for manufacturing a pack housing, including the steps of preparing a mold for integrally extruding a heat sink and side frames on both sides of a pack housing, the step of integrally extruding a pack housing semi-finished product excluding a front frame and a rear frame using the mold, and the step of welding together a front frame and a rear frame manufactured separately to the pack housing semi-finished product.

[0017] In one embodiment, the pack housing semi-finished product may integrally include a center frame arranged in the central region of the heat sink so as to be parallel to the side frames.

[0018] And, the above mold can produce a pair of pack housing semi-finished products in batches.

[0019] For example, the pair of pack housing semi-finished products can be formed in a batch to form a mirror-symmetrical shape based on the center of the mold.

[0020] And, the mold can collectively manufacture the pack housing semi-finished product and the front frame and rear frame.

[0021] In one embodiment, the front frame and the rear frame can be joined to the pack housing semi-finished product by CMT welding.

[0022] According to the pack housing of the present invention having the above-described structure, most of the pack housing, specifically the heat sink constituting the bottom plate and a pair of side frames, are formed as an integral body through extrusion molding without forming separate joint surfaces. Accordingly, the manufacturing process of the pack housing is simplified, thereby improving productivity. In addition, since the welding process, which was previously performed multiple times, is omitted, difficulties in dimensional control due to warping are also resolved.

[0023] However, the technical effects that can be obtained through the present invention are not limited to the above-described effects, and other effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0024] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0025] Figure 1 is a drawing showing an example of a pack housing manufacturing process according to conventional technology.

[0026] FIG. 2 is a drawing illustrating an example of a pack housing semi-finished product according to one embodiment of the present invention.

[0027] Figure 3 is a drawing showing an example of combining front and rear frames to a pack housing semi-finished product.

[0028] Figure 4 is a flowchart of a method for manufacturing a pack housing according to one embodiment of the present invention.

[0029] Fig. 5 is a drawing showing an example of a mold suitable for manufacturing a pack housing semi-finished product.

[0030] Fig. 6 is a drawing showing another example of a mold suitable for manufacturing a pack housing semi-finished product.

[0031] Figure 7 is a drawing showing an example of a mold for manufacturing front and rear frames together with pack housing semi-finished products.

[0032] The present invention can be modified in various ways and has many embodiments, and specific embodiments will be described in detail below.

[0033] However, this is not intended to limit the present invention to a specific embodiment, but should be understood to include all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

[0034] In the present invention, it should be understood that terms such as “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0035] Additionally, in the present invention, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only cases where it is "directly above" the other part, but also cases where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only cases where it is "directly below" the other part, but also cases where there is another part in between. Furthermore, in the present application, "being placed on" may include cases where it is placed below as well as above.

[0036]

[0037] The present invention relates to a pack housing comprising a heat sink, a pair of side frames coupled to both sides of the heat sink, and a front frame and a rear frame coupled to the front and rear of the heat sink, wherein in one example, the heat sink and the pair of side frames are integrally formed by extrusion molding, so that no separate bonding surface is formed between the heat sink and the pair of side frames.

[0038] According to the pack housing of the present invention having the above-described structure, most of the pack housing, specifically the heat sink constituting the bottom plate and a pair of side frames, are formed as an integral body through extrusion molding without forming separate joint surfaces. Accordingly, the manufacturing process of the pack housing is simplified, thereby improving productivity. In addition, since the welding process, which was previously performed multiple times, is omitted, difficulties in dimensional control due to warping are also resolved.

[0039] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the attached drawings. The directions used in the following description to designate relative positions, such as front / back, up / down, left / right, etc., are intended to aid understanding of the invention, and unless otherwise specified, the directions depicted in the drawings will be taken as the reference.

[0040]

[0041] [First Embodiment]

[0042] The present invention relates to a pack housing (10) including a heat sink (110), a pair of side frames (120) coupled to both sides of the heat sink (110), and a front frame (130) and a rear frame (140) coupled to the front and rear of the heat sink (110). FIG. 2 is a drawing illustrating a pack housing semi-finished product (100), and in this specification, an entire structure including a heat sink (110) and a pair of side frames (120) coupled to both sides thereof is referred to as a pack housing semi-finished product (100).

[0043] Referring to Fig. 2, the heat sink (110) and the pair of side frames (120) are integrally formed by extrusion molding. That is, the entire pack housing semi-finished product (100) is manufactured in one piece by extrusion molding, and accordingly, no separate bonding surface is formed between the heat sink (110) and the pair of side frames (120).

[0044] The pack housing (10) of the present invention, when divided by component basis, is composed of a pack housing semi-finished product (100), a front frame (130), and a rear frame (140). Compared to the prior art of FIG. 1, the pack housing (10) of the present invention does not have a welding operation for connecting a plurality of heat sinks (110) and side frames (120) into one, and there is no joint surface accompanying the welding. Therefore, the manufacturing process of the pack housing (10) is simplified, thereby improving productivity. In addition, since the welding process, which was performed multiple times in the past, is omitted, the difficulty in dimensional control due to warping caused by welding heat is also resolved. As dimensional control becomes easier, the possibility of dimensional defects occurring is reduced, which also leads to improved productivity.

[0045] Due to the nature of extrusion molding, a protruding structure in a parallel direction can be extruded, but a structure in a direction different from this cannot be extruded. That is, the heat sink (110) and the side frame (120) in the parallel direction together with the internal rib (112) structure can be manufactured in one batch by extrusion molding. On the other hand, the front frame (130) and the rear frame (140) in the direction orthogonal to the side frame (120) cannot be manufactured in one batch, and are therefore manufactured separately and then welded to the heat sink (110). Fig. 3 is a drawing illustrating an example of combining the front and rear frames (130, 140) to the pack housing semi-finished product (100).

[0046] Here, a plurality of ribs (112) formed inside the heat sink (110) are spaced apart from each other by a predetermined distance, and a hollow passage (114) is formed between the plurality of ribs (112). This hollow passage (114) can be used as a cooling path through which a refrigerant flows.

[0047] According to an embodiment, the pack housing (10) may be provided with a center frame in the central area of ​​the heat sink (110). The center frame corresponds to a frame member that divides rows when battery cells, not shown in the drawing, are arranged in two rows. The direction of the center frame is parallel to a pair of side frames (120). Therefore, the center frame may also be manufactured in bulk by extrusion molding to form a part of the pack housing semi-finished product (100). As described above, since the heat sink (110) and the center frame are formed integrally by extrusion molding, no separate bonding surface is formed between the heat sink (110) and the center frame.

[0048]

[0049] [Second Embodiment]

[0050] Fig. 4 is a flowchart of a method for manufacturing a pack housing (10) according to one embodiment of the present invention. Referring to Fig. 4, a method for manufacturing a pack housing (10) according to one embodiment of the present invention will be described.

[0051] First, among the entire structure of the pack housing (10), a mold (200) is prepared for integrally extruding the heat sink (110) and the side frames (120) on both sides. That is, the pack housing semi-finished product (100) is manufactured by the mold (200). The extrusion direction of the pack housing semi-finished product (100) is parallel to the extension direction of the side frames (120). Accordingly, the mold (200) is provided with an injection port (210) corresponding to the cross-section cut along the "AA" line of FIG. 2.

[0052] Once the mold (200) is prepared, the pack housing semi-finished product (100) excluding the front frame (130) and the rear frame (140) is integrally extruded using the mold (200). The pack housing semi-finished product (100) can be manufactured from a metal material suitable for the pack housing (10), for example, aluminum. The pack housing semi-finished product (100) is continuously manufactured by extrusion molding, and after extrusion molding, it is cut to a designed length, thereby preparing a plurality of pack housing semi-finished products (100).

[0053] When the pack housing semi-finished product (100) is prepared, the separately manufactured front frame (130) and rear frame (140) are welded to the pack housing semi-finished product (100). By joining the front frame (130) and the rear frame (140), a pack housing (10) as illustrated in FIG. 3 is produced. In one embodiment, the front frame (130) and the rear frame (140) may be joined to the pack housing semi-finished product (100) by CMT welding. CMT welding is a low heat input welding method that can minimize thermal deformation, and improves the dimensional quality of the pack housing (10) by minimizing warping that may occur during the welding of the front frame (130) and the rear frame (140). And, after welding the front frame (130) and the rear frame (140), the pack housing (10) can be completed by performing machining, such as milling, drilling, grinding, or other cutting processing, on the pack housing (10).

[0054] Fig. 5 is a drawing illustrating an example of a mold (200) suitable for manufacturing a pack housing semi-finished product (100). In Fig. 5, the mold (200) is illustrated as having a circular cross-section, and in particular, is illustrated as having an injection port (210) in the form of a center frame parallel to a side frame (120) arranged in the central area of ​​a heat sink (110).

[0055] And, since the pack housing semi-finished product (100) including the side frame (120) is quite large in size, the mold (200) can also be enlarged accordingly. It may not be efficient to manufacture the pack housing semi-finished product (100) in one line with such a large mold (200). Considering this point, the mold (200) of FIG. 6 has two injection ports (210) of the same shape so as to manufacture a pair of pack housing semi-finished products (100) in one batch. For example, a pair of pack housing semi-finished products (100) can be molded in one batch with a mirror-symmetrical shape based on the center (diameter) of the mold (200). Since the two injection ports (210) form a mirror-symmetrical shape, it becomes easy to uniformly manage the quality of the pack housing semi-finished products (100) manufactured in two rows.

[0056] And, Fig. 7 illustrates another example of a mold (200) applicable to the present invention. According to the mold (200) of Fig. 7, the front and rear frames (130, 140) can be manufactured in a batch together with the pack housing semi-finished product (100). That is, the mold (200) of Fig. 7 is provided with an injection port (210) corresponding to the cross-sectional shape of the front and rear frames (130, 140) as well as the pack housing semi-finished product (100).

[0057] Accordingly, all parts required to form a pack housing (10), i.e., a pack housing semi-finished product (100) and front and rear frames (130, 140), can be manufactured in one batch using a single mold (200). Since all parts of the pack housing (10) are manufactured using a single mold line, subsequent welding work, such as that of the front and rear frames (130, 140), can be efficiently performed.

[0058]

[0059] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

[0060]

[0061] [Explanation of symbols]

[0062] 10: Pack Housing

[0063] 100: Pack housing semi-finished product

[0064] 110: Heatsink

[0065] 112: Live

[0066] 114: Hollow passage

[0067] 120: Side Frame

[0068] 130: Front frame

[0069] 140: Rear frame

[0070] 150: Center Frame

[0071] 200: Mold

[0072] 210: Ejection port

Claims

1. A pack housing including a heat sink, a pair of side frames coupled to both sides of the heat sink, and a front frame and a rear frame coupled to the front and rear of the heat sink, A pack housing in which the heat sink and a pair of side frames are integrally formed by extrusion molding, and thus no separate bonding surface is formed between the heat sink and the pair of side frames.

2. In paragraph 1, The above front frame and rear frame are welded to the above heat sink, pack housing.

3. In paragraph 2, The above pack housing has a center frame parallel to the pair of side frames in the central area of ​​the above heat sink, A pack housing in which the heat sink and the center frame are formed integrally by extrusion molding, and thus no separate bonding surface is formed between the heat sink and the center frame.

4. In paragraph 1, The above heat sink, A pack housing comprising a plurality of ribs spaced apart from each other and formed in a direction parallel to the pair of side frames, and a hollow passage formed between the plurality of ribs.

5. Step of preparing a mold for integrally extruding the heat sink of the pack housing and the side frames on both sides; A step of integrally extruding and manufacturing a pack housing semi-finished product excluding the front frame and the rear frame using the above mold; and A step of welding together a front frame and a rear frame manufactured separately for the above pack housing semi-finished product; A method for manufacturing a pack housing, comprising:

6. In paragraph 5, The above pack housing semi-finished product is, A method for manufacturing a pack housing, comprising: integrally providing a center frame arranged in the central area of ​​the heat sink so as to be parallel to the side frame.

7. In paragraph 5, The above mold, A method for manufacturing a pack housing, which involves manufacturing a pair of pack housing semi-finished products in batches.

8. In paragraph 7, A method for manufacturing a pack housing, wherein the above pair of pack housing semi-finished products are formed in a single batch to form a mirror-symmetrical shape based on the center of the mold.

9. In paragraph 5, The above mold, A method for manufacturing a pack housing, comprising manufacturing the above pack housing semi-finished product and the front frame and rear frame in one batch.

10. In paragraph 5, The above front frame and rear frame, A method for manufacturing a pack housing, wherein the above pack housing semi-finished product is joined by CMT welding.

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