Copper-aluminum busbar with interlocking interface

Abstract

A busbar having an interlocking interface includes an aluminum (Al) body. The aluminum body includes an upper surface and a lower surface opposite the upper surface. The busbar also includes a first copper (Cu) coil embedded within the aluminum body. The first Cu coil includes a first outer surface flush with the upper surface of the aluminum body. The first Cu coil also includes a first inner surface opposite the first outer surface. The first Cu coil also includes a first set of side surfaces between and connected to the first outer surface and the first inner surface. The first Cu coil also includes a first edge formed by the first set of side surfaces and the first inner surface. The first edge defines a first angle between 20 degrees and 70 degrees.

Description

Technical Field

[0001] This disclosure relates to a busbar for vehicles. More specifically, this disclosure relates to a copper-aluminum (Cu-Al) busbar for vehicles with an interlocking interface. Background Technology

[0002] The development and application of rechargeable secondary batteries have driven the advancement of electric and hybrid electric vehicle technologies. Secondary batteries provide energy for electric traction motors, servo motors, and other electronic devices in vehicles. Busbars are used to establish switching connections between motor windings and to connect the windings to phase connectors that interface with power electronics. Busbars can be made in various shapes and are typically made of copper or aluminum. The material composition determines the maximum current they can carry. Busbars can also be made of both copper and aluminum, thus reducing the weight of the secondary battery. However, interface reliability can be a problem with copper-aluminum busbars. During operation, copper-aluminum busbars are subjected to cyclical electrical and thermal loads, mechanical vibrations, and corrosion.

[0003] Therefore, although the current copper-aluminum busbars have achieved their intended purpose, new and improved designs are still needed to enhance their reliability during operation. Summary of the Invention

[0004] According to several aspects, a busbar with an interlocking interface is provided. The busbar includes an aluminum (Al) body. The aluminum body includes an upper surface and a lower surface opposite to the upper surface. The busbar also includes a first copper (Cu) coil embedded within the aluminum body. The first copper coil includes a first outer surface flush with the upper surface of the aluminum body. The first copper coil also includes a first inner surface opposite to the first outer surface. The first copper coil also includes a first set of side surfaces located between and connected to the first outer surface and the first inner surface. The first copper coil also includes a first edge formed by the connection of the first set of side surfaces and the first inner surface. The first edge defines a first angle, the first angle being between 20 degrees and 70 degrees.

[0005] In another aspect of this disclosure, the first edge is tapered.

[0006] In another aspect of this disclosure, at least a portion of the periphery of the first copper coil is coated with one of the following: tin (Sn), nickel (Ni), and silver (Ag).

[0007] In another aspect of this disclosure, the first set of side surfaces defines a first width that increases from the first inner surface to the first outer surface.

[0008] In another aspect of this disclosure, the first set of side surfaces defines a first width that decreases from the first inner surface to the first outer surface.

[0009] In another aspect of this disclosure, the busbar also includes a second copper coil embedded within the aluminum body. The second copper coil includes a second outer surface flush with the lower surface of the aluminum body. The second copper coil also includes a second inner surface opposite the second outer surface. The second copper coil also includes a second set of side surfaces located between and connected to the second outer and second inner surfaces. The second set of side surfaces defines a second width that decreases from the second inner surface to the second outer surface. The second copper coil also includes a second edge formed by the connection of the second set of side surfaces and the second inner surface. The second edge defines a second angle between 20 degrees and 70 degrees.

[0010] In another aspect of this disclosure, the first edge of the first copper coil and the second edge of the second copper coil are tapered.

[0011] In another aspect of this disclosure, the busbar also includes an intermediate copper portion. The intermediate copper portion is located between the first copper coil and the second copper coil, and connects the first copper coil and the second copper coil.

[0012] According to several aspects, a method for forming a busbar is provided. The method includes heating aluminum (Al) to form liquid aluminum. The method further includes guiding the liquid aluminum to a water-cooled roller. The method further includes feeding a first copper (Cu) coil between the water-cooled rollers. The first copper coil contacts the upper surface of the liquid aluminum. The water-cooled roller applies pressure to the first copper coil and the liquid aluminum. The pressure embeds the first copper coil into the liquid aluminum. The method further includes cooling the liquid aluminum using the water-cooled roller, solidifying the liquid aluminum, and bonding the first copper coil to the solid aluminum. The method further includes using the solid aluminum and the first copper coil to create a tension coil, thereby forming the busbar.

[0013] In another aspect of this disclosure, the method further includes cutting the first copper coil into a first desired shape before feeding it between water-cooled rollers. The first desired shape includes a first outer surface flush with the upper surface of the aluminum. The first desired shape also includes a first inner surface opposite the first outer surface. The first desired shape further includes a first set of side surfaces. The first set of side surfaces defines a first angle. The first angle is between 20 and 70 degrees.

[0014] In another aspect of this disclosure, the first desired shape defines a first width that increases from the first inner surface to the first outer surface.

[0015] In another aspect of this disclosure, the first desired shape defines a first width that decreases from the first inner surface to the first outer surface.

[0016] In another aspect of this disclosure, the method further includes cutting a second copper coil into a second desired shape. The second desired shape includes a second outer surface flush with the lower surface of the aluminum. The second desired shape also includes a second inner surface opposite the second outer surface. The second desired shape further includes a second set of side surfaces. The second set of side surfaces defines a second angle. The second angle is between 20 and 70 degrees. The method further includes feeding the cut second copper coil between water-cooling rollers. The cut second copper coil contacts the lower surface of the liquid aluminum. The water-cooling rollers apply pressure to the cut second copper coil and the liquid aluminum. The pressure embeds the cut second copper coil into the liquid aluminum. The water-cooling rollers solidify the liquid aluminum, bonding the cut second copper coil to the solid aluminum.

[0017] In another aspect of this disclosure, the first desired shape defines a first width that decreases from the first inner surface to the first outer surface. The second desired shape defines a second width that decreases from the second inner surface to the second outer surface.

[0018] In another aspect of this disclosure, the first copper coil is a plurality of pultruded copper coils.

[0019] In another aspect of this disclosure, multiple pultruded copper pieces are hollow.

[0020] According to several aspects, a method for forming a busbar is provided. The method includes heating aluminum (Al) to form liquid aluminum. The method further includes guiding the liquid aluminum to water-cooled rollers. The method also includes cutting a first copper (Cu) coil into a first desired shape. The first desired shape includes a first outer surface, a first inner surface, and a first set of side surfaces. The first set of side surfaces defines a first angle. The first angle is between 20 and 70 degrees. The method further includes feeding the cut first copper coil between the water-cooled rollers. The cut first copper coil contacts the upper surface of the liquid aluminum. The water-cooled rollers apply pressure to the cut first copper coil and the liquid aluminum. The pressure embeds the cut first copper coil into the liquid aluminum. The method further includes cooling the liquid aluminum with the water-cooled rollers, solidifying the liquid aluminum, and bonding the cut first copper coil to the solid aluminum. The method also includes using the solid aluminum and the cut first copper coil to create a tension coil, thereby forming a busbar.

[0021] In another aspect of this disclosure, the first desired shape defines a first width that increases from the first inner surface to the first outer surface.

[0022] In another aspect of this disclosure, the first desired shape defines a first width that decreases from the first inner surface to the first outer surface.

[0023] In another aspect of this disclosure, the method further includes cutting a second copper coil into a second desired shape. The second desired shape includes a second outer surface flush with the lower surface of the aluminum. The second desired shape also includes a second inner surface opposite the second outer surface. The second desired shape further includes a second set of side surfaces. The second set of side surfaces defines a second angle between 20 degrees and 70 degrees. The second desired shape defines a second width decreasing from the second inner surface to the second outer surface. The method further includes feeding the cut second copper coil between water-cooling rollers. The cut second copper coil contacts the lower surface of the liquid aluminum. The water-cooling rollers apply pressure to the cut second aluminum and the liquid aluminum. The pressure embeds the cut second copper coil into the liquid aluminum. The water-cooling rollers solidify the liquid aluminum, bonding the cut second copper coil to the solid aluminum.

[0024] Further areas of application will become apparent from the description provided herein. It should be understood that the descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0025] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0026] Figure 1A This is a perspective view of multiple busbars within a vehicle according to an exemplary embodiment.

[0027] Figure 1B It is an enlarged view of multiple buses connected to multiple battery cells.

[0028] Figure 2A This is a cross-sectional view of the busbar according to an exemplary embodiment.

[0029] Figure 2B This is a cross-sectional view of an alternative busbar according to an exemplary embodiment.

[0030] Figure 2C This is a cross-sectional view of another alternative busbar according to an exemplary embodiment.

[0031] Figure 2D This is a cross-sectional view of yet another alternative busbar according to an exemplary embodiment.

[0032] Figure 3 This is an enlarged cross-sectional view of the tapered edge of the busbar according to an exemplary embodiment.

[0033] Figure 4A This is an enlarged cross-sectional view of the coating covering a portion of the busbar according to an exemplary embodiment.

[0034] Figure 4B This is an enlarged cross-sectional view of the coating covering an alternative portion of the busbar according to an exemplary embodiment.

[0035] Figure 5A This is a cross-sectional view of a busbar with copper wires according to an exemplary embodiment.

[0036] Figure 5B This is a cross-sectional view of a busbar with alternative copper wires according to an exemplary embodiment.

[0037] Figure 6 This is a side view of twin-roll casting for manufacturing busbars according to an exemplary embodiment.

[0038] Figure 7 This is a side view of an alternative twin-roll casting method for manufacturing busbars according to an exemplary embodiment.

[0039] Figure 8 This is a method for manufacturing a busbar according to an exemplary embodiment.

[0040] Figure 9 This is an alternative method for manufacturing busbars according to an exemplary embodiment. Detailed Implementation

[0041] The following description is exemplary in nature and is not intended to limit this disclosure, application, or purpose.

[0042] refer to Figure 1A The diagram illustrates multiple busbars 10 disposed within a vehicle 12. The vehicle 12 includes multiple battery cells 14 and a motor 18. The multiple battery cells may be, but are not limited to, prismatic, cylindrical, or pouch-type battery cells. The multiple battery cells 14 supply electrical energy to the motor 18. The multiple busbars 10 are connected to the multiple battery cells 14 and conduct electrical energy from the multiple battery cells 14, transferring energy to the motor 18. The multiple busbars 10 may be connected to the multiple battery cells 14 using wire bonding, laser welding, or other bonding or welding processes.

[0043] It should be understood that Figure 1A This is merely an example, and the multiple buses 10 are not limited to power distribution within a vehicle. In practice, the multiple buses 10 can be used in a variety of other electric vehicles and stationary applications. It should also be understood that the vehicle 12 can be any type of vehicle, such as, but not limited to, a car, truck, SUV, van, or motorhome.

[0044] refer to Figure 1B An enlarged view is shown of multiple busbars 10 connected to multiple battery cells 14. The multiple busbars 10 can be connected in series. The series connection adds the voltage from each of the multiple battery cells 14, ensuring that the total voltage required for the operation of the vehicle 12 is supplied by the motor 18 (e.g., ...). Figure 1A(As shown) Receives. The total voltage of a hybrid electric vehicle is between 100 and 200 volts (V). The total voltage of an electric vehicle is between 400 and 800 volts.

[0045] The ability of multiple busbars 10 to transfer power from multiple battery cells 14 to the motor 18 depends on the composition of the multiple busbars 10. The multiple busbars 10 consist of at least a first copper coil 20 and an aluminum body 22. The first copper coil 20 has high conductivity, enabling efficient power transfer and minimizing power loss. The high conductivity of the first copper coil 20 also allows for effective heat dissipation, reducing the risk of overheating of the multiple battery cells 14. The first copper coil 20 is durable and resistant to mechanical wear. The aluminum body 22 has lower conductivity and durability than the first copper coil 20, but is lighter in weight. The combination of these two metals allows the busbars to retain the advantages of the first copper coil 20 while reducing the weight of the multiple battery cells 14.

[0046] refer to Figure 2A A cross-sectional view of one of a plurality of busbars 10 is shown. It should be understood that each of the plurality of busbars 10 is identical, therefore only one busbar 10 will be described herein. The busbar 10 is formed by a first copper coil 20 embedded within an aluminum body 22. The aluminum body 22 has an upper surface 24, a lower surface 26, a left surface 28, and a right surface 30. The upper surface 24 is opposite to the lower surface 26, thereby defining an aluminum thickness 32. The left surface 28 is opposite to the right surface 30, thereby defining an aluminum width 34. The left surface 28 and the right surface 30 are located between and connected to the upper surface 24 and the lower surface 26. The aluminum body 22 also includes a longitudinal length 36 (e.g., Figure 1B As shown), the upper surface 24, lower surface 26, left surface 28, and right surface 30 extend along this longitudinal length. The first copper coil 20 is embedded within the aluminum body 22 and extends along the longitudinal length 36 (as shown). Figure 1B (As shown).

[0047] The first copper coil 20 can be cut into a first desired shape 37 having a first outer surface 38, a first inner surface 40, and a first set of side surfaces 42. The first outer surface 38 is flush with the upper surface 24 of the aluminum body 22. The first inner surface 40 is opposite to the first outer surface 38, thereby defining a first copper thickness 44. The first copper thickness 44 is between 5% and 30% of the aluminum thickness 32. The first set of side surfaces 42 defines a first copper width 46, and the first copper width 46 is smaller than the aluminum width 34. The first set of side surfaces 42 is located between and connected to the first outer surface 38 and the first inner surface 40, thereby defining the first copper width 46. The connection between the first set of side surfaces 42 and the first inner surface 40 defines a first set of edges 48. The first set of edges 48 defines a first angle 50, thereby changing the first copper width 46 as it moves from the first inner surface 40 to the first outer surface 38. The first angle 50 is between 20 degrees and 70 degrees, causing the first copper width 46 to increase as it moves from the first inner surface 40 to the first outer surface 38.

[0048] refer to Figure 2B A cross-sectional view of the alternative busbar 10, indicated by reference numeral 52, is shown. Busbar 52 includes... Figure 2A The aluminum body 22 is shown. The busbar 52 also includes a first copper coil 54. The first copper coil 54 can be cut into a first desired shape 55 having a first outer surface 56, a first inner surface 58, and a first set of side surfaces 60. The first outer surface 56 is flush with the upper surface 24 of the aluminum body 22. The first inner surface 58 is opposite to the first outer surface 38, thereby defining a first copper thickness 62. The first copper thickness 62 is between 5% and 30% of the aluminum thickness 32. The first set of side surfaces 60 defines a first copper width 64, and the first copper width 64 is smaller than the aluminum width 34. The first set of side surfaces connects to and is located between the first outer surface 56 and the first inner surface 58. The connection between the first set of side surfaces 60 and the first inner surface 58 defines a first set of edges 66. The first set of edges 66 defines a first angle 68, thereby changing the first copper width 64 as it travels from the first inner surface 58 to the first outer surface 56. The first angle 68 is between 20 degrees and 70 degrees, causing the first copper width 64 to decrease as it moves from the first inner surface 58 to the first outer surface 56.

[0049] refer to Figure 2C A cross-sectional view of the alternative busbar 52, indicated by reference numeral 70, is shown. Busbar 70 includes... Figure 2BThe aluminum body 22 and the first copper coil 54 are shown. The busbar 70 also includes a second copper coil 72. The second copper coil 72 can be cut into a second desired shape 73 having a second outer surface 74, a second inner surface 76, and a second set of side surfaces 78. The second outer surface 74 is flush with the lower surface 26 of the aluminum body 22. The second inner surface 76 is opposite to the second outer surface 74, thereby defining a second copper thickness 80. The second copper thickness 80 is between 5% and 30% of the aluminum thickness 32. The second set of side surfaces 78 is located between and connected to the second outer surface 74 and the second inner surface 76, thereby defining a second copper width 82. The second copper width 82 is smaller than the aluminum width 34. The connection between the second set of side surfaces 78 and the second inner surface 76 defines a second set of edges 84. The second set of edges 84 defines a second angle 86, thereby changing the second copper width 82 as it travels from the second inner surface 76 to the second outer surface 74. The second angle 86 is between 20 degrees and 70 degrees, causing the second copper width 82 to decrease as it moves from the second inner surface 76 to the second outer surface 74.

[0050] refer to Figure 2D A cross-sectional view of an alternative embodiment of busbar 70, indicated by reference numeral 88, is shown. Busbar 88 includes... Figure 2C The diagram shows an aluminum body 22, a first copper coil 54, and a second copper coil 72. The busbar 88 also includes an intermediate copper portion 90. The intermediate copper portion 90 is connected to a first inner surface 58 of the first copper coil 54 and a second inner surface 76 of the second copper coil 72. The intermediate copper portion 90 defines an intermediate width 92. The intermediate width 92 is smaller than the first copper width 64 and the second copper width 82.

[0051] Figure 2A-2D Buses 10, 52, 70, and 88 with an interlocking Cu-Al design are shown. The interlocking design is achieved by embedding first copper coils 20 and 54 into an aluminum body 22. A second copper coil 72 can also be embedded into the aluminum body 22. The first angles 50 and 68 of the first copper coils 20 and 54, and the second angle 86 of the second copper coil 72, enhance the bond between the aluminum body 22 and the first copper coils 20 and 54, thereby enhancing and improving the reliability of buses 10, 52, 70, and 88. Furthermore, the first angles 50 and 68 and the second angle 86 allow for more uniform thermal expansion during operation of buses 10, 52, 70, and 88.

[0052] refer to Figure 3 The diagram shows enlarged cross-sectional views of busbars 10, 52, 70, and 88. The first set of edges 48, 66, and the second set of edges 84 may be tapered, with radii between 0.05 and 0.5 millimeters (mm). The tapered first set of edges 48, 66, and the tapered second set of edges 84 avoid stress concentration, thereby preventing cracking.

[0053] refer to Figure 4A and Figure 4B The image shows an enlarged cross-sectional view of busbars 10, 52, 70, and 88 with coating 94. Figure 4A A coating 94 is shown covering a portion of the periphery of the first copper coils 20, 54. The coating 94 may also be applied to cover a portion of the periphery of the second copper coil 72 (not shown). Alternatively, Figure 4B A coating 94 covering the periphery of the first copper coils 20, 54 is shown. A coating 94 may also be applied to cover the periphery of the second copper coil 72 (not shown). The coating 94 may be, but is not limited to, tin (Sn), nickel (Ni), or silver (Ag). The coating 94 covering at least a portion of the periphery of the first copper coils 20, 54 and / or at least a portion of the second copper coil 72 helps to prevent the growth of intermetallic compounds and enables better bonding with the first copper coils 20, 54 and the aluminum body 22, as well as the second copper coil 72 and the aluminum body 22.

[0054] refer to Figure 5A A cross-sectional view of the alternative busbar 10, indicated by reference numeral 96, is shown. Busbar 96 includes... Figure 2A The aluminum body 22 is shown. The busbar 96 also includes a first copper coil 98. The first copper coil 98 is formed from multiple pultruded copper coils. The first copper coil 98 is uniformly disposed within the aluminum body 22, enhancing and improving the reliability of the busbar 96. It should be understood that... Figure 5A This is merely an example, and the first copper coil 98 is not limited to having a circular cross-section. The first copper coil 98 may have a non-circular cross-section.

[0055] refer to Figure 5B A cross-sectional view of the alternative busbar 96, indicated by reference numeral 100, is shown. Busbar 100 includes... Figure 5A The aluminum body 22 is shown. The busbar 100 also includes a first copper coil 102. The first copper coil 102 is made of multiple pultruded copper strands. The first copper coil 102 is hollow and uniformly arranged within the aluminum body 22, enhancing and improving the reliability of the busbar 100. It should be understood that... Figure 5B This is merely an example, and the first copper coil 102 is not limited to having a circular cross-section. The first copper coil 102 may have a non-circular cross-section.

[0056] refer to Figure 6 , Figure 8 and Figure 9 , Figure 6 This is a flowchart of method 200 for making busbars 10, 52, 70, 88, 96, and 100. Figure 8 and Figure 9This is a schematic diagram illustrating method 200. Method 200 begins with step 202. In step 202, the aluminum body 22 is heated to produce liquid aluminum. In step 204, the liquid aluminum is guided to the water-cooled roller 104.

[0057] In step 206, the first copper coils 20 and 54 are cut into the first desired shapes 37 and 55. In step 208, the first copper coils 20 and 54 are fed between the water-cooling rollers 104, contacting the upper surface 24 of the liquid aluminum. The water-cooling rollers 104 apply pressure to the first outer surfaces 38 and 56 of the first copper coils 20 and 54 and the upper surface 24 of the liquid aluminum. The pressure applied to the first copper coils 20 and 54 embeds them into the liquid aluminum.

[0058] In step 210, the second copper coil 72 can be cut into a second desired shape 73. In step 212, the cut second copper coil 72 can be simultaneously fed into the water-cooling rollers 104 along with the first copper coils 20 and 54. The second copper coil 72 contacts the lower surface 26 of the liquid aluminum. The water-cooling rollers apply pressure to the second outer surface 74 of the second copper coil 72 and the lower surface 26 of the liquid aluminum. The pressure applied to the second copper coil 72 embeds it into the liquid aluminum.

[0059] In step 214, liquid aluminum is cooled by a water-cooling roller 104. Cooling the liquid aluminum solidifies it, thus bonding the solid aluminum to the embedded first copper coils 20 and 54. If the second copper coil 72 is embedded in the liquid aluminum before cooling, the cooling of the liquid aluminum bonds the solid aluminum to the embedded second aluminum coil 72. In step 216, a tension coil 106 is made using the solid aluminum and the bonded first copper coils 20 and 54. If the second copper coil 72 is embedded in the liquid aluminum, the tension coil 106 is made of solid aluminum, the bonded first copper coils 20 and 54, and the bonded second copper coil 72. Buses 10, 52, 70, 88, 96, and 100 are made of the tension coil 106.

[0060] refer to Figure 7 , Figure 8 and Figure 9 , Figure 7 It is a flowchart of method 300 for making busbars 10, 52, 70, and 88, and... Figure 8 and Figure 9 This is a schematic diagram illustrating method 300. Method 300 begins with step 302. In step 302, the aluminum body 22 is heated to produce liquid aluminum. In step 304, the liquid aluminum is guided to the water-cooled roller 104.

[0061] In step 306, the first copper coils 20 and 54 are cut into the first desired shapes 37 and 55. In step 308, the cut first copper coils 20 and 54 are fed between water-cooling rollers 104, contacting the upper surface 24 of the liquid aluminum. The water-cooling rollers 104 apply pressure to the first outer surfaces 38 and 56 of the cut first copper coils 20 and 54 and the upper surface 24 of the liquid aluminum. Due to the first angles 50 and 68 of the first set of side surfaces 42 and 60, the pressure applied to the cut first copper coils 20 and 54 is partially vertical. The partially vertical pressure applied to the cut first copper coils 20 and 54 embeds them into the liquid aluminum, forming a reliable bond under thermal expansion during use.

[0062] In step 310, the second copper coil 72 can be cut into a second desired shape 73. In step 312, the cut second copper coil 72 can be simultaneously fed between the cut first copper coils 20 and 54 and the water-cooling rollers 104. The cut second copper coil 72 contacts the lower surface 26 of the liquid aluminum. The water-cooling rollers 104 apply pressure to the second outer surface 74 of the cut second copper coil 72 and the lower surface 26 of the liquid aluminum. Due to the second angle 86 of the second side surface 78, the pressure applied to the cut second copper coil 72 is partially vertical. The partially vertical pressure applied to the cut second copper coil 72 embeds the cut second copper coil 72 into the liquid aluminum and forms a reliable bond under thermal expansion during use.

[0063] In step 314, liquid aluminum is cooled by a water-cooling roller 104. Cooling the liquid aluminum solidifies it, thus bonding the solid aluminum with the embedded cut first copper coils 20 and 54. If the cut second copper coil 72 is embedded in the liquid aluminum before cooling, the cooling of the liquid aluminum will bond the solid aluminum with the embedded cut second copper coil 72. In step 316, a tension coil 106 is made using the solid aluminum and the combined cut first copper coils 20 and 54. If the cut second copper coil 72 is embedded in the liquid aluminum, the tension coil 106 is made of solid aluminum, the combined cut first copper coils 20 and 54, and the combined cut second copper coil 72. Busbars 10, 52, 70, and 88 are made of the tension coil 106.

[0064] The busbars 10, 52, 70, 88, 96, and 100 disclosed herein have several advantages, including enhanced and improved busbar reliability while reducing the mass of multiple battery cells 14. Furthermore, the first desired shapes 37 and 55 of the first copper coils 20 and 54, and the second desired shape 73 of the second copper coil 72, enhance the bond with the aluminum body 22, thereby achieving more uniform thermal expansion.

[0065] The description in this disclosure is merely exemplary in nature, and any modifications that do not depart from the spirit and scope of this disclosure are intended to fall within its scope. Such modifications should not be considered as departing from the spirit and scope of this disclosure.

Claims

1. A busbar with an interlocking interface, the busbar comprising: An aluminum Al body, comprising an upper surface and a lower surface opposite to the upper surface; as well as A first copper (Cu) coil, embedded within the aluminum body, the first copper coil comprising: The first outer surface is flush with the upper surface of the aluminum body; A first inner surface, which is opposite to the first outer surface; A first set of side surfaces, located between and connected to the first outer surface and the first inner surface; and A first edge is formed by connecting the first set of side surfaces and the first inner surface, wherein the first edge defines a first angle between 20 degrees and 70 degrees.

2. The busbar according to claim 1, wherein, The first edge is tapered.

3. The busbar according to claim 1, wherein, At least a portion of the periphery of the first copper coil is coated with one of the following: tin (Sn), nickel (Ni), and silver (Ag).

4. The busbar according to claim 1, wherein, The first set of side surfaces defines a first width that increases from the first inner surface to the first outer surface.

5. The busbar according to claim 1, wherein, The first set of side surfaces defines a first width that decreases from the first inner surface to the first outer surface.

6. The busbar according to claim 5 further includes a second copper coil embedded in the aluminum body, the second copper coil comprising: The second outer surface is flush with the lower surface of the aluminum body; The second inner surface is opposite to the second outer surface; A second set of side surfaces is located between and connected to the second outer surface and the second inner surface, wherein the second set of side surfaces defines a second width that decreases from the second inner surface to the second outer surface; as well as The second edge is formed by the connection of the second set of side surfaces and the second inner surface, wherein the second edge defines a second angle between 20 degrees and 70 degrees.

7. The busbar according to claim 6, wherein, The first edge of the first copper coil and the second edge of the second copper coil are tapered.

8. The busbar according to claim 6 further includes an intermediate copper portion, wherein the intermediate copper portion is located between the first copper coil and the second copper coil, and the intermediate copper portion connects the first copper coil and the second copper coil.

9. A method for forming a busbar, comprising: Heating the aluminum (Al) bulk to form liquid aluminum; The liquid aluminum is guided to the water-cooled roller; A first copper coil (Cu) is fed between the water-cooling rollers, wherein the first copper coil is in contact with the upper surface of the liquid aluminum, wherein the water-cooling rollers apply pressure to the first copper coil and the liquid aluminum, and wherein the pressure embeds the first copper coil into the liquid aluminum. The liquid aluminum is cooled by the water-cooling roller, the liquid aluminum is solidified, and the first copper coil is bonded to the solid aluminum. as well as A tensioning coil is made using the solid aluminum and the first copper coil, thereby forming a busbar.

10. The method of claim 9, further comprising cutting the first copper coil into a first desired shape before feeding the first copper coil between the water-cooled rollers, the first desired shape comprising: The first outer surface is flush with the upper surface of the aluminum body; A first inner surface, which is opposite to the first outer surface; as well as A first set of side surfaces, wherein the first set of side surfaces defines a first angle, and wherein the first angle is between 20 degrees and 70 degrees.

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