Friction stir welding method, and battery pack cooling block manufacturing method using the same and battery pack cooling block manufactured by the same

Abstract

The present invention relates to an improved friction stir welding method, a method for manufacturing a cooling block for a vehicle battery pack using said friction stir welding method, and a cooling block for a vehicle battery pack manufactured by said method. The improved friction stir welding method of the present invention comprises: a welding flange additional forming step of additionally forming first and second welding flanges, respectively, on a welding portion of a first material including a cooling block top plate and a second material including a cooling block bottom plate to be welded with said cooling block top plate; a welding flange alignment step of butting and aligning said first and second welding flanges; a material welding step using friction stir welding of welding said welding portion together with said buttingly aligned first and second welding flanges using a predetermined friction stir welding (FSW); and a welding flange cutting step of cutting said first and second welding flanges to remove said first and second welding flanges.

Description

Technology Field

[0001] The present invention relates to an improved friction stir welding method, a method for manufacturing a cooling block for a vehicle battery pack using said friction stir welding method, and a cooling block for a vehicle battery pack manufactured by said method. More specifically, the invention relates to an improved friction stir welding method that can provide significantly improved welding strength compared to conventional methods by preventing pinhole formation even when rotary stirring for welding is performed, and can also ensure watertightness through defect-free welding by welding the upper and lower plates of the cooling block using friction stir welding (FSW), and can provide significantly improved welding strength compared to conventional methods by preventing pinhole formation. The invention also relates to a method for manufacturing a cooling block for a vehicle battery pack using said friction stir welding method and a cooling block for a vehicle battery pack manufactured by said method. Background Technology

[0002] Friction Stir Welding (FSW) is a solid-state joining method that welds by utilizing reverse flow within the material using a specific amount of frictional heat.

[0003] Compared to conventional fusion welding methods such as arc welding, laser welding, and electron beam welding, it is characterized by the absence of blowholes or cracks and minimal deformation during welding. It is currently widely applied in railway vehicles, ships, aircraft, and automobiles.

[0004] Meanwhile, among automobiles, hybrid electric vehicles, fuel cell vehicles, and electric vehicles are all vehicles driven by electric motors. These vehicles are necessarily equipped with a high-voltage battery pack that provides driving power to the electric motor. The high-voltage battery pack is configured to supply the necessary power by repeatedly charging and discharging during vehicle operation.

[0005] A conventional high-voltage battery pack includes a battery case, a plurality of battery modules mounted within the battery case, and a Battery Management System (BMS) that detects the voltage, current, and temperature of each unit cell constituting the battery module and controls its operation.

[0006] Battery cases are typically made of steel, aluminum, or stainless steel. While steel battery cases offer the advantages of lower cost and higher strength compared to aluminum or stainless steel, they have the disadvantages of being heavy and negatively impacting fuel efficiency. Consequently, the use of aluminum or stainless steel battery cases has recently been increasing, as they offer high thermal conductivity and allow for weight reduction to achieve lightweight design and improved fuel efficiency.

[0007] The temperature of high-voltage battery packs continuously rises due to heat generation during charging and discharging. If the battery temperature rises excessively, it causes performance degradation and shortens its lifespan, and in severe cases, poses a risk of fire.

[0008] Therefore, high-voltage battery packs are essentially equipped with a cooling device, namely a cooling block, to cool the battery to an appropriate temperature. This cooling block serves to dissipate heat from the high-voltage battery pack by cooling the battery case.

[0009] Examples of cooling block applications include air-cooled devices and water-cooled devices; water-cooled devices are known to offer better cooling efficiency than air-cooled ones. A cooling block cools the battery case by creating passages for the flow of cooling water on the upper and lower plates of a block with a specific shape.

[0010] Meanwhile, the cooling block implemented with upper and lower plates can also be manufactured using the aforementioned friction stir welding (FSW) method and is reported to be applied in actual field applications. While it is true that friction stir welding (FSW) possesses various advantages as previously mentioned, the need for an improved welding method arises because the rotational stirring at the inlet (start) and outlet (end) sections of FSW carries a high risk of pinhole formation, which can lead to a decrease in weld rigidity. Prior art literature

[0011] Korean Intellectual Property Office Application No. 10-2018-0036957 The problem to be solved

[0012] The objective of the present invention is to provide an improved friction stir welding method that can provide significantly improved welding strength compared to conventional methods by preventing the occurrence of pinholes even when rotary stirring for welding is performed.

[0013] Another objective of the present invention is to provide a method for manufacturing a cooling block for a vehicle battery pack using a friction stir welding method, and a cooling block for a vehicle battery pack manufactured by said method, which can ensure watertightness through defect-free welding by welding the upper and lower plates of the cooling block together using friction stir welding (FSW), and also provide welding strength that is significantly improved compared to conventional methods by preventing the occurrence of pinholes. means of solving the problem

[0014] The above objective is achieved by an improved friction stir welding method characterized by comprising: a welding flange additional forming step of additionally forming first and second welding flanges, respectively, at a welding portion of a first material including a cooling block top plate and a second material including a cooling block bottom plate to be welded with the cooling block top plate; a welding flange alignment step of butting the first and second welding flanges; a material welding step using friction stir welding of welding the welding portion together with the buttingly aligned first and second welding flanges using a predetermined friction stir welding (FSW); and a welding flange cutting step of cutting the first and second welding flanges to remove the first and second welding flanges.

[0015] The above objective is achieved by: a cooling block top plate preparation step for preparing a cooling block top plate, which is one side of a vehicle battery pack cooling block; a cooling block bottom plate preparation step for preparing a cooling block bottom plate to be welded and integrated with the cooling block top plate; a cooling block top plate and a cooling block bottom plate contact surface placement step for arranging the cooling block top plate and the cooling block bottom plate so that a cooling water flow path is formed between the cooling block top plate and the cooling block bottom plate; a welding position selection step for selecting welding positions of the cooling block top plate and the cooling block bottom plate arranged in contact surfaces; and a friction stir welding step for performing welding along the selected welding positions using a predetermined friction stir welding (FSW) to integrate the cooling block top plate and the cooling block bottom plate into a single body. This is also achieved by a method for manufacturing a cooling block for a vehicle battery pack using a friction stir welding method, which includes a welding quality inspection step for determining the quality of a product by inspecting the welded portions of the upper plate of the cooling block and the lower plate of the cooling block, and is characterized in that the upper plate preparation step of the cooling block and the lower plate preparation step of the cooling block proceed independently in parallel.

[0016] The above objective is also achieved by a vehicle battery pack cooling block manufactured by the method of claim 2, comprising: a cooling block top plate forming one side of the vehicle battery pack cooling block; and a cooling block bottom plate integrated into one body with the cooling block top plate through welding so as to form a cooling water flow path between the cooling block top plate and the cooling block bottom plate, wherein the cooling block top plate and the cooling block bottom plate are welded by friction stir welding (FSW) to integrate into one body.

[0017] In order to form the above cooling water flow path, a flow path upper plate portion is formed on the upper plate of the cooling block and a flow path lower plate portion is formed on the lower plate of the cooling block, wherein a plurality of flow path branching protrusions are formed on the lower plate portion of the flow path to branch the direction of the cooling water flow path in multiple directions, and the thickness of the upper plate of the cooling block may be manufactured to be thicker than the thickness of the lower plate of the cooling block. Effects of the invention

[0018] According to the present invention, even when rotary stirring for welding is performed, there is no occurrence of pinholes, so it is possible to provide welding strength that is significantly improved compared to conventional methods.

[0019] In addition, according to the present invention, by welding and joining the upper and lower plates of a cooling block using Friction Stir Welding (FSW), not only can watertightness be ensured through defect-free welding, but the absence of pinholes also provides the effect of significantly improved welding strength compared to conventional methods. Brief explanation of the drawing

[0020] FIG. 1 is a flowchart of an improved friction stir welding method according to a first embodiment of the present invention. Figure 2 is a schematic diagram illustrating the improved friction stir welding method of Figure 1. FIG. 3 is a flowchart of a method for manufacturing a cooling block for a vehicle battery pack using a friction stirring welding method according to a second embodiment of the present invention. Figures 4 to 9 are step-by-step process diagrams according to the manufacturing method of Figure 3. FIG. 10 is a drawing of a vehicle battery pack cooling block manufactured by the method of manufacturing a vehicle battery pack cooling block using the friction stir welding method of FIG. 3. FIGS. 11 and 12 are process diagrams of key parts of a method for manufacturing a cooling block for a vehicle battery pack using a friction stirring welding method according to a third embodiment of the present invention. FIG. 13 is a process diagram of the main parts of a method for manufacturing a cooling block for a vehicle battery pack using a friction stirring welding method according to the fourth embodiment of the present invention. Specific details for implementing the invention

[0021] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings.

[0022] However, the present invention is not limited to the embodiments disclosed below but will be implemented in various different forms.

[0023] In this specification, the embodiments are provided to make the disclosure of the invention complete and to fully inform those skilled in the art of the scope of the invention. The invention is defined only by the scope of the claims.

[0024] Accordingly, in some embodiments, well-known components, well-known operations, and well-known techniques are not specifically described to avoid the invention being interpreted ambiguously.

[0025] Throughout the specification, the same reference numerals refer to the same components. Furthermore, the terms used (mentioned) in this specification are for describing the embodiments and are not intended to limit the invention.

[0026] In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. Additionally, components and actions (operations) referred to as 'comprising (or having)' do not exclude the presence or addition of one or more other components and actions.

[0027] Unless otherwise defined, all terms used in this specification (including technical and scientific terms) may be used in a meaning that is commonly understood by those skilled in the art to which the present invention belongs.

[0028] Furthermore, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless otherwise defined.

[0029] This invention was developed based on the following national project.

[0030] 1. Research Management Agency: Gyeongbuk Embedded Research Institute

[0031] 2. Research Project Name: Future Automotive Parts Conversion Corporate R&D Project

[0032] 3. Research Project Title: Development of Stainless Steel Battery Case Manufacturing Technology for Next-Generation EV Commercial Vehicle Platforms

[0033] 4. Contribution Rate: 1:1

[0034] 5. Organizer: Sewon E&I Co., Ltd.

[0035] 6. Study Period: August 1, 2024 – March 31, 2025 (※8 months)

[0036] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings.

[0037] FIG. 1 is a flowchart of an improved friction stir welding method according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram for explaining the improved friction stir welding method of FIG. 1.

[0038] Referring to these drawings, the improved friction stir welding method according to the present embodiment can provide significantly improved welding strength compared to the conventional method by preventing the occurrence of pinholes even when rotary stirring for welding is performed.

[0039] The improved friction stir welding method according to the present embodiment, which can provide such effects, may include a welding flange additional forming step (S10), a welding flange alignment step (S20), a material welding step using friction stir welding (S30), and a welding flange cutting step (S40).

[0040] The welding flange additional forming step (S10) is a process of additionally forming first and second welding flanges (11, 21) respectively at the welding portions of a first material (10) including a cooling block top plate as in FIG. 1 and FIG. 2a and a second material (20) including a cooling block bottom plate to be welded with the cooling block top plate.

[0041] The first material (10) may be the top plate of the cooling block (110, see FIG. 4) of the embodiment below, and the second material (20) may be the top plate of the cooling block (120, see FIG. 5) of the embodiment below. Of course, the first material (10) and the second material (20) may be two bonded materials unrelated to the cooling block.

[0042] The welding flange alignment step (S20) is a process of butting and aligning the first and second welding flanges (11, 21) as shown in FIGS. 1 and 2b. By carrying out this process, the welded area is also aligned.

[0043] The material welding step (S30) using friction stir welding is a process of welding the weld area using a predetermined friction stir welding (FSW; Friction Stir Welding) together with the first and second welding flanges (11, 21) aligned butt-joint as in FIG. 1 and FIG. 2c.

[0044] Here, Friction Stir Welding (FSW) is a solid-state joining method that welds by reverse flow within the material using a predetermined frictional heat. Compared to conventional fusion welding methods such as arc welding, laser welding, and electron beam welding, it is characterized by the absence of blowholes or cracks and minimal deformation during welding. It is currently widely applied in railway vehicles, ships, aircraft, automobiles, etc.

[0045] The welding flange cutting step (S40) is a process of cutting the first and second welding flanges (11, 21) to remove the first and second welding flanges (11, 21) as in FIGS. 1 and 2d. This step may be laser cutting.

[0046] Hereinafter, an improved friction stir welding method according to the present embodiment will be described in sequence.

[0047] First, as in FIGS. 1 and 2a, first and second welding flanges (11, 21) are additionally formed at the welding portions of the first material (10) including the upper plate of the cooling block and the second material (20) including the lower plate of the cooling block to be welded to the upper plate of the cooling block.

[0048] As described above, the first material (10) may be the top plate of the cooling block (110, see FIG. 4) of the embodiment below, and the second material (20) may be the top plate of the cooling block (120, see FIG. 5) of the embodiment below. Of course, the first material (10) and the second material (20) may be two bonded materials unrelated to the cooling block.

[0049] Next, the first and second welding flanges (11, 21) are butted and aligned as in FIGS. 1 and FIGS. 2b. By carrying out this process, the welded area is also aligned.

[0050] Next, the weld area is welded using a predetermined friction stir welding (FSW) together with the first and second weld flanges (11, 21) aligned butt-joint as in FIG. 1 and FIG. 2c.

[0051] Then, as in FIGS. 1 and 2d, by cutting the first and second welding flanges (11, 21) to remove the first and second welding flanges (11, 21), it can contribute to improving the welding quality.

[0052] According to the present embodiment, which operates with the structure described above, even when rotary stirring for welding is performed, no pinholes occur, thereby providing significantly improved welding strength compared to conventional methods.

[0053] FIG. 3 is a flowchart of a method for manufacturing a vehicle battery pack cooling block using a friction stir welding method according to a second embodiment of the present invention, FIG. 4 to 9 are step-by-step process diagrams according to the manufacturing method of FIG. 3, and FIG. 10 is a drawing of a vehicle battery pack cooling block manufactured by the method for manufacturing a vehicle battery pack cooling block using a friction stir welding method of FIG. 3.

[0054] Referring to these drawings, the present invention ensures watertightness through defect-free welding by welding and joining the upper and lower plates (110, 120) of a cooling block using friction stir welding different from conventional methods, and furthermore, eliminates the phenomenon of fire or equipment failure caused by leakage of cooling water due to welding defects. In particular, it can provide significantly improved welding strength compared to conventional methods by eliminating the occurrence of pinholes.

[0055] The present invention, which can provide such effects, may be applied to the method for manufacturing a vehicle battery pack cooling block of FIG. 3 and the vehicle battery pack cooling block (100) of FIG. 10.

[0056] First, a method for manufacturing a cooling block for a vehicle battery pack according to one embodiment of the present invention is described. The method for manufacturing a cooling block for a vehicle battery pack according to this embodiment may include a step of preparing an upper plate of the cooling block (S110), a step of preparing a lower plate of the cooling block (S120), a step of arranging the contact surfaces of the upper and lower plates of the cooling block (S130), a step of selecting a welding location (S140), a friction stir welding step (S150), and a welding quality inspection step (S160).

[0057] The cooling block top plate preparation step (S110) is a process of preparing a cooling block top plate (110), which is one side of a vehicle battery pack cooling block (100), as shown in FIGS. 3 and 4.

[0058] The cooling block bottom plate preparation step (S120) is a process of preparing a cooling block bottom plate (130) to be welded and integrated with the cooling block top plate (110) as shown in FIGS. 3 and 5. At this time, the cooling block top plate preparation step (S110) and the cooling block bottom plate preparation step (S120) can proceed independently in parallel. That is, either one can be performed first.

[0059] The step of arranging the upper and lower plates of the cooling block in contact (S130) is a process of arranging the upper plate (110) and the lower plate (130) of the cooling block in contact so that a cooling water channel (120) through which cooling water flows is formed between the upper plate (110) and the lower plate (130) of the cooling block as shown in FIGS. 3 and FIGS. 6.

[0060] The welding position selection step (S140) is a process of selecting the welding position (140) of the upper cooling block plate (110) and the lower cooling block plate (130) arranged in contact surfaces as in FIGS. 3 and FIGS. 7. The welding position (140) may be directly marked, or only the position may be determined according to a program.

[0061] The friction stir welding step (S150) is a process in which welding is performed by a friction stir welding device (150) along selected welding positions (140) as shown in FIGS. 3 and 8, so that the upper plate (110) of the cooling block and the lower plate (130) of the cooling block are integrated into one body.

[0062] The welding quality inspection step (S160) is a process for determining the quality of a product by inspecting the welded parts of the upper plate (110) and the lower plate (130) of the cooling block using a welding inspection device (160) as shown in FIGS. 3 and 9. Through this process, only good quality products are supplied, and the finished product is the cooling block (100) of FIG. 10.

[0063] The structure of the cooling block (100) manufactured in this manner is described in more detail. The cooling block (100) includes a plate-shaped cooling block upper plate (110) and a cooling block lower plate (130). The cooling block upper plate (110) and the cooling block lower plate (130) are integrated through the aforementioned friction stirring welding to form a single cooling block (100).

[0064] The cooling block top plate (110) forms the upper plate body of the cooling block (100) provided for cooling a vehicle battery pack.

[0065] And, the cooling block bottom plate (130) is a part that forms the lower plate body of the cooling block (100), and is integrated into one body with the cooling block top plate (110) through friction stirring welding so that a cooling water flow path (120) through which cooling water flows is formed between it and the cooling block top plate (110).

[0066] At this time, in order to form a cooling water channel (120), a channel upper plate (111) is formed on the upper plate (110) of the cooling block and a channel lower plate (131) is formed on the lower plate (130) of the cooling block, and a plurality of channel branching protrusions (132) are formed on the channel lower plate (131) to branch the direction of the cooling water channel (120) in several directions.

[0067] Even if there is only one space for the lower section of the Euro (131), multiple Euro branch protrusions (132) are formed in the lower section of the Euro (131), and cooling water flows through them, so the cooling efficiency can be increased. That is, the cooling efficiency can be increased because the heated cooling water can be recovered and cold cooling water can be supplied.

[0068] In this embodiment, the thickness of the upper plate (110) of the cooling block is made thicker than the thickness of the lower plate (130) of the cooling block.

[0069] Below, a series of processes for manufacturing a cooling block (100) is introduced.

[0070] First, as shown in FIGS. 3 and 4, a cooling block top plate (110), which is one side of a vehicle battery pack cooling block (100), is prepared.

[0071] Next, a cooling block bottom plate (130) to be welded and integrated with the cooling block top plate (110) as shown in FIGS. 3 and 5 is prepared. At this time, the cooling block top plate preparation step (S110) and the cooling block bottom plate preparation step (S120) can proceed independently in parallel. That is, either one can be performed first.

[0072] Next, as shown in FIGS. 3 and 6, the upper plate (110) of the cooling block and the lower plate (130) of the cooling block are placed in contact with each other so that a cooling water channel (120) through which cooling water flows is formed between the upper plate (110) of the cooling block and the lower plate (130).

[0073] Next, the welding location (140) of the upper cooling block plate (110) and the lower cooling block plate (130) arranged in contact surfaces as in FIGS. 3 and FIGS. 7 is selected. The welding location (140) may be directly marked, or only the location may be determined according to a program.

[0074] Next, welding is performed by friction stirring welding using a friction stirring welding device (150) along selected welding positions (140) as in FIGS. 3 and 8, so that the upper plate (110) of the cooling block and the lower plate (130) of the cooling block are integrated into one body.

[0075] Then, as shown in FIGS. 3 and 9, the quality of the product is determined by inspecting the welded parts of the upper plate (110) and the lower plate (130) of the cooling block using a welded part inspection device (160). Through this process, only good quality products are supplied, and the finished product is the cooling block (100) of FIG. 10.

[0076] According to the present embodiment, which operates based on the structure described above, by welding the upper and lower plates (110, 120) of the cooling block together using Friction Stir Welding (FSW), watertightness can be ensured through defect-free welding, and welding strength can be provided that is significantly improved compared to conventional methods by preventing the occurrence of pinholes.

[0077] FIGS. 11 and 12 are process diagrams of key parts of a method for manufacturing a cooling block for a vehicle battery pack using a friction stirring welding method according to a third embodiment of the present invention.

[0078] Referring to these drawings, in the case of the present embodiment as well, the upper plate (110) of the cooling block and the lower plate (130) are welded together through friction stirring welding by a friction stirring welding device (150).

[0079] However, in the case of the present embodiment, a first laser irradiation groove (270) is formed on the top plate (110) of the cooling block before friction stir welding is performed. Then, the friction stir welding device (150) performs friction stir welding through the first laser irradiation groove (270). Then, not only can an accurate welding position be provided, but a welding bead can also be filled into the first laser irradiation groove (270), thereby providing a stronger welding quality.

[0080] Even when this embodiment is applied, by welding the upper and lower plates (110, 120) of the cooling block together using Friction Stir Welding (FSW), not only can watertightness be ensured through defect-free welding, but welding strength can also be provided that is significantly improved compared to conventional methods by preventing the occurrence of pinholes.

[0081] FIG. 13 is a process diagram of the main parts of a method for manufacturing a cooling block for a vehicle battery pack using a friction stirring welding method according to the fourth embodiment of the present invention.

[0082] Referring to this drawing, in this embodiment as well, the upper plate (110) of the cooling block and the lower plate (130) of the cooling block are welded together through friction stirring welding by a friction stirring welding device (150).

[0083] However, in the case of this embodiment, two first and second laser irradiation grooves (270, 370) are formed, and friction stir welding is performed on both of them. In this case, since double welding is performed on one welding area, it can be more effective in preventing leakage.

[0084] Even when this embodiment is applied, by welding the upper and lower plates (110, 120) of the cooling block together using Friction Stir Welding (FSW), not only can watertightness be ensured through defect-free welding, but welding strength can also be provided that is significantly improved compared to conventional methods by preventing the occurrence of pinholes. Explanation of the symbols

[0085] 100 : Cooling block 110 : Cooling block top plate 111: Euro top plate 120: Coolant flow path 130: Cooling block bottom plate 131: Flow path bottom plate section 132: Euro branch projection 140: Welding position 150: Friction stir welding device 160: Welding area inspection device

Claims

Claim 1 An improved friction stir welding method characterized by comprising: a welding flange additional forming step of additionally forming first and second welding flanges, respectively, at a welding portion of a first material including a cooling block top plate and a second material including a cooling block bottom plate to be welded with the cooling block top plate; a welding flange alignment step of butting the first and second welding flanges; a material welding step using friction stir welding, in which the welding portion is welded together with the buttingly aligned first and second welding flanges using a predetermined friction stir welding (FSW); and a welding flange cutting step of cutting the first and second welding flanges to remove the first and second welding flanges. Claim 2 A method for manufacturing a cooling block for a vehicle battery pack using a friction stir welding method, comprising: a cooling block upper plate preparation step for preparing a cooling block upper plate, which is one side of the cooling block for a vehicle battery pack; a cooling block lower plate preparation step for preparing a cooling block lower plate to be welded and integrated with the cooling block upper plate; a cooling block upper plate and a cooling block lower plate contact surface arrangement step for arranging the cooling block upper plate and the cooling block lower plate so that a cooling water flow path is formed between the cooling block upper plate and the cooling block lower plate, thereby forming a cooling water flow path between them; a welding position selection step for selecting a welding position of the cooling block upper plate and the cooling block lower plate arranged in contact surfaces; a friction stir welding step for performing welding through a predetermined friction stir welding (FSW) along the selected welding position so that the cooling block upper plate and the cooling block lower plate are integrated into one body; and a welding quality inspection step for inspecting the welded parts of the cooling block upper plate and the cooling block lower plate to determine the quality of the product, wherein the cooling block upper plate preparation step and the cooling block lower plate preparation step proceed independently in parallel. Claim 3 A cooling block for a vehicle battery pack, manufactured by the method of claim 2, comprising: a cooling block top plate forming one side of the cooling block for a vehicle battery pack; and a cooling block bottom plate integrated into one body with the cooling block top plate through welding so as to form a cooling water flow path between the cooling block top plate and the cooling block bottom plate, wherein the cooling block top plate and the cooling block bottom plate are welded by friction stir welding (FSW) to integrate into one body. Claim 4 A vehicle battery pack cooling block according to claim 3, wherein, for the formation of the cooling water flow path, a flow path upper plate portion is formed on the upper plate of the cooling block and a flow path lower plate portion is formed on the lower plate of the cooling block, and a plurality of flow path branching protrusions are formed on the lower plate of the cooling block to branch the direction of the cooling water flow path in multiple directions, and wherein the thickness of the upper plate of the cooling block is manufactured to be thicker than the thickness of the lower plate of the cooling block.

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