A copper bar, a copper bar processing die and a copper bar heat dissipation capacity calculation method

Abstract

The application discloses a copper bar, a copper bar processing die and a copper bar heat dissipation capacity calculation method, and relates to the technical field of copper bars. The copper bar comprises at least two layers of copper foils arranged in a stacking manner along a first direction, and each copper foil comprises a bending segment protruding towards the same side of the first direction; in the bending segment: in the first direction, two side plates are located on the same side of the middle plate and have a corner between the middle plate and the two side plates; between two adjacent bending segments along the first direction, one bending segment extends into the recessed space of the other bending segment, and all the bending segments arranged in sequence along the first direction form an arch part; along the first direction, between two adjacent middle plates, there is a heat dissipation gap penetrating in a third direction, and between two adjacent side plates, corresponding adhesion is achieved. Since the arch part has the heat dissipation gap, the heat dissipation capacity of the copper bar can be improved; the middle plate and the side plate of the bending segment have the corner, so that the structural stability can be ensured, the risk of deformation and collapse of the arch part and the possibility of disappearance of the heat dissipation gap caused thereby can be reduced.

Description

Technical Field

[0001] This invention relates to the field of copper busbar technology, and in particular to a copper busbar, a copper busbar processing mold, and a method for calculating the heat dissipation capacity of a copper busbar. Background Technology

[0002] Copper busbars, as a low-impedance conductor, are widely used in high-current connection scenarios such as power transmission, new energy battery packs, energy storage high-voltage boxes, and electrical cabinets. Currently, one type of copper busbar on the market is a soft copper busbar that is formed by stacking multiple layers of copper foil and then welding (such as brazing or diffusion welding) to press the two ends or the whole into a single piece. Structurally, soft copper busbars are usually densely stacked sheets with the copper foil layers tightly bonded together.

[0003] However, as electrical equipment develops towards higher power density, the current that copper busbars need to carry is increasing. Such copper busbars have insufficient heat dissipation capacity, which may even cause safety hazards.

[0004] Therefore, how to improve heat dissipation capacity is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a copper busbar, a copper busbar processing mold, and a method for calculating the heat dissipation capacity of the copper busbar, which has a high heat dissipation capacity.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A first aspect of the present invention provides a copper busbar comprising at least two layers of copper foil stacked along a first direction, each copper foil including a bent segment protruding from the same side facing the first direction; each bent segment includes an intermediate plate and two side plates located on opposite sides of the intermediate plate in a second direction, wherein the two side plates are located on the same side of the intermediate plate in the first direction and have an angle with the intermediate plate respectively; between two adjacent bent segments along the first direction, one bent segment extends into the recessed space of the other bent segment, thereby forming an arched portion of all the bent segments arranged sequentially along the first direction; a heat dissipation gap is provided between two adjacent intermediate plates along the first direction and extending through a third direction, and the two adjacent side plates along the first direction are correspondingly fitted together.

[0007] In one exemplary embodiment, the bending section is a trapezoidal groove structure with an open bottom; wherein, the middle plate is a plate corresponding to the upper bottom, and the two side plates are plates corresponding to the two waists respectively.

[0008] In one exemplary embodiment, the intermediate plate is a flat plate and perpendicular to the first direction; the intermediate plates in the arched portion are arranged at equal intervals along the first direction.

[0009] In one exemplary embodiment, the intermediate plate is provided with heat dissipation holes extending through the first direction.

[0010] In one exemplary embodiment, it includes one or at least two copper busbar units arranged sequentially along the second direction. The copper busbar unit includes an arched portion and two fixing portions respectively disposed on both sides of the arched portion in the second direction. The copper foil includes connecting segments respectively disposed on both sides of the bent section in the second direction. The connecting segments that are connected to each other on the same side of each bent section in the same arched portion are respectively aligned and welded together along the first direction to form a fixing portion.

[0011] A second aspect of the present invention provides a copper busbar processing mold for forming the copper busbar as described above. The copper busbar processing mold includes: a concave mold comprising a plurality of cavities arranged sequentially and connected along a preset direction, wherein the bottom depth of each cavity gradually increases along one direction of the preset direction, and the cavity with the largest bottom depth is a first cavity; and a convex mold for stamping flat copper foil raw materials placed on each cavity to form copper foils having the bending section respectively; wherein, after each copper foil is stamped, it is completely staggered in the depth direction of the cavity, and each copper foil can slide along the preset direction to the first cavity, and automatically form a structure of stacked arrangement in the depth direction.

[0012] In one exemplary embodiment, the die cavity is further provided with a receiving groove, which is located in the preset direction on the side of the first cavity away from the other cavities; the receiving groove is used to receive one end of the copper foil from all the other cavities except the first cavity in the preset direction.

[0013] In one exemplary embodiment, each cavity extends in the same direction, and the die has a feeding groove at both ends of the extension direction of each cavity; the feeding groove is used for the copper foil material to be inserted into the corresponding cavity through the feeding groove, and the two ends of the copper foil material are respectively placed in the corresponding feeding groove; the punch is also provided with a cut to cut off the portion of the copper foil material located in the feeding groove and the portion in the cavity during the stamping process.

[0014] In one exemplary embodiment, the punch includes a plurality of working ends arranged sequentially along the preset direction; after the punch extends into the die along the depth direction, each of the working ends is used to punch each of the copper foil raw materials one by one, so that each of the copper foil raw materials simultaneously forms the copper foil with the bending section.

[0015] A third aspect of the present invention provides a method for calculating the heat dissipation capacity of a copper busbar, applied to the copper busbar described above; the method includes: establishing a thermal balance judgment condition for the copper busbar: |heating power - heat dissipation power| ≤ allowable tolerance, wherein the heating power and the heat dissipation power are both functions of the copper busbar temperature; and solving for the thermal balance temperature of the copper busbar that satisfies the thermal balance judgment condition.

[0016] In one exemplary embodiment, the heating power is:

[0017] In the formula: I: Current flowing through the copper busbar; T0: The selected reference temperature; Resistance of the copper busbar at temperature T0; α: Temperature coefficient of resistance; T: The thermal equilibrium temperature to be calculated.

[0018] In one exemplary embodiment, the heat dissipation power is:

[0019] j: Different surface partitions of the copper busbar under natural convection; : j-zone area; : Natural convection heat transfer coefficient in region j; p: Different surface partitions under radiative heat dissipation; :p partition area; : Radiation heat transfer coefficient in region p; T: The thermal equilibrium temperature to be calculated; Ambient temperature.

[0020] The copper busbar provided by the present invention includes at least two layers of copper foil stacked along a first direction, each copper foil including a bent section protruding from the same side facing the first direction; the bent section includes a middle plate and two side plates located on both sides of the middle plate in a second direction, the two side plates being located on the same side of the middle plate in the first direction and having an angle with the middle plate respectively; between two adjacent bent sections along the first direction, one bent section extends into the recessed space of the other bent section, thereby forming an arched portion of all the bent sections arranged sequentially along the first direction; there is a heat dissipation gap through a third direction between two adjacent middle plates along the first direction, and the two adjacent side plates along the first direction are correspondingly fitted together.

[0021] The aforementioned copper busbar, due to the heat dissipation gap between the intermediate plates of the arched section, provides heat dissipation space for adjacent copper foils to allow airflow, thereby improving the heat dissipation capacity of the copper busbar. It has a high efficiency in heat exchange with air and can carry a larger current. Compared with the traditional copper busbar where the copper foils are completely bonded together, the heat dissipation efficiency can be significantly improved when other parameters are basically the same, such as the cross-section perpendicular to the extension direction. The corner between the intermediate plate and the side plate in the bending section can increase the bending section's resistance to deformation, and the corresponding bonding between the side plates of adjacent copper foils can support and limit each other, thereby ensuring the structural strength of the arched section, ensuring the structural stability of the copper busbar, reducing the risk of deformation and collapse of the arched section, and reducing the possibility of the heat dissipation gap disappearing as a result. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a first isometric view of the copper busbar in an embodiment of the present invention; Figure 2 This is a second isometric view of the copper busbar in an embodiment of the present invention; Figure 3 This is a front view of the copper busbar in an embodiment of the present invention; Figure 4 This is an exploded view of the copper busbar in an embodiment of the present invention; Figure 5 for Figure 4 Enlarged view of point A; Figure 6 This is an isometric view of another copper busbar in an embodiment of the present invention; Figure 7 This is an isometric view of the concave die of the copper busbar processing mold in an embodiment of the present invention; Figure 8 This is a top view of the concave die of the copper busbar processing mold in an embodiment of the present invention; Figure 9 for Figure 8 AA section diagram; Figure 10 This is a left view of the concave die of the copper busbar processing mold in an embodiment of the present invention; Figure 11 This is a right view of the concave die of the copper busbar processing mold in an embodiment of the present invention; Figure 12 This is a schematic diagram of the copper foil raw material feeding process in an embodiment of the present invention; Figure 13 This is a first isometric view of the punch of the copper busbar processing mold in an embodiment of the present invention; Figure 14 This is a second isometric view of the punch of the copper busbar processing mold in an embodiment of the present invention; Figure 15 for Figure 14 Enlarged view of point B; Figure 16 This is a left view of the punch of the copper busbar processing mold in an embodiment of the present invention; Figure 17 This is a schematic diagram of the punch closing motion in an embodiment of the present invention, with the arrows indicating the direction of punch movement; Figure 18 This is a schematic diagram of the closed state of the punch and die in an embodiment of the present invention. The arrow indicates the direction in which the punch is about to return. Figure 19 This is a schematic diagram of copper foil sliding down the receiving trough in an embodiment of the present invention; Figure 20 This is a schematic diagram of the copper foil after it has been positioned by the receiving trough in an embodiment of the present invention; Figure 21 This is a schematic diagram of the structural parameters of a copper busbar having one copper busbar unit in an embodiment of the present invention; Figure 22 for Figure 21 Schematic diagram of structural parameters for the upper and middle bending sections; Figure 23 for Figure 21 Schematic diagram of structural parameters of the central fixing part.

[0024] Explanation of reference numerals in the attached figures: 1. Copper foil, 11. Bending section, 111. Middle plate, 112. Side plate, 112. Connecting section, 12. Heat dissipation hole, 13. Arched part 2; Fixing part 3, fixing through hole 31; Heat dissipation gap 4; Die 5, cavity 51, first cavity 511, cavity bottom surface 512, feeding channel 52, receiving channel 53, guide post 54; Punch 6, working end 61, forming working surface 611, cut 62, ejector pin 63, push module 64, guide hole 65; Copper busbar unit 7; 8. Copper foil raw material. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The core of this invention is to provide a copper busbar, a copper busbar processing mold, and a method for calculating the heat dissipation capacity of the copper busbar. The copper busbar has a high heat dissipation capacity and can be applied to high-current connection scenarios such as power transmission, new energy battery packs, energy storage high-voltage boxes, and electrical cabinets.

[0027] For a specific embodiment of the copper busbar provided by this invention, please refer to [the specific embodiment]. Figures 1 to 5 It includes at least two layers of copper foil 1 stacked along the first direction Z, wherein the copper foil 1 is soft copper foil. The number of stacked layers of copper foil 1 is determined by the specific current flow requirements.

[0028] like Figure 4 As shown, the bending segment 11 includes a middle plate 111 and two side plates 112 located on either side of the middle plate 111 in the second direction X. In a single bending segment 11, in the first direction Z, the two side plates 112 are located on the same side of the middle plate 111 and have an angle with the middle plate 111 respectively. At this time, the bending angle of each layer of copper foil 1 between the middle plate 111 and the side plates 112 can be set to be the same, for example, the bending angle of each corner is 120°, or they can be different.

[0029] Between two adjacent bending segments 11 along the first direction Z, one bending segment 11 extends into the recessed space of the other bending segment 11, thus forming an arched portion 2 from all the bending segments 11 arranged sequentially along the first direction Z. (Reference) Figure 1 Taking the first direction Z as the vertical direction as an example, each copper foil 1 is arranged vertically, and each bent section 11 protrudes upward. Between adjacent copper foils 1, the bent section 11 of the lower copper foil 1 extends upward or is embedded into the concave side of the bent section 11 of the upper copper foil 1.

[0030] like Figure 3 As shown, between two adjacent bent sections 11 in the arched portion 2, there is a heat dissipation gap 4 extending along the third direction Y between two adjacent intermediate plates 111 in the first direction Z, and the two adjacent side plates 112 in the first direction Z are correspondingly fitted together. The heat dissipation gap 4 can serve as an airflow channel, using airflow to carry away the heat on the copper foil 1.

[0031] The first direction Z, the second direction X, and the third direction Y are all perpendicular to each other.

[0032] It should be noted that the side plates 112 in the arched portion 2 are fitted together along the first direction Z and the joint is not fixedly connected. In other embodiments, they can also be fixedly connected as one piece. In addition, the corresponding fit between the side plates 112 does not require that the two side plates 112 be fitted together all over the entire surface. The presence of contact in a local area can also be regarded as corresponding fit.

[0033] In this embodiment, the copper busbar has a heat dissipation gap 4 between the middle plates 111 of the arched portion 2, which provides heat dissipation space for adjacent copper foils 1 to allow air flow, thereby improving the heat dissipation capacity of the copper busbar, enabling it to efficiently exchange heat with air and carry a larger current. The middle plate 111 and the side plate 112 in the bent section 11 have a corner, which increases the bending section 11's resistance to deformation. The corresponding fit between the side plates 112 of adjacent copper foils 1 can support and limit each other, thereby ensuring the structural strength of the arched portion 2, ensuring the structural stability of the copper busbar, reducing the risk of deformation and collapse of the arched portion 2 and the possibility of the heat dissipation gap 4 disappearing as a result.

[0034] In some embodiments, such as Figure 4 As shown, the bending section 11 is a trapezoidal groove structure with an open bottom. The middle plate 111 is the plate corresponding to the upper bottom of the trapezoid, and the two side plates 112 are the plates corresponding to the two waists of the trapezoid respectively.

[0035] At this time, since the bending section 11 is a trapezoidal groove structure with an open bottom, during the assembly and forming process of the bending sections 11 of the adjacent copper foils 1, such as Figure 4 As shown, the two side plates 112 of the extended bending section 11 can serve as guides, facilitating the smooth fitting of the bending sections 11 of adjacent copper foils 1 and reducing assembly difficulty.

[0036] In some embodiments, such as Figure 3 As shown, the trapezoidal groove structure of the bending section 11 is an isosceles trapezoid, that is, the two side plates 112 in the bending section 11 have equal angles with the middle plate 111, and the two side plates 112 have equal lengths, which facilitates the processing of the bending section 11.

[0037] In some embodiments, such as Figure 3 and Figure 4 As shown, the intermediate plate 111 is a flat plate and perpendicular to the first direction Z. At this time, the different intermediate plates 111 are parallel to each other, so that the height of a single heat dissipation gap 4 is the same everywhere in the first direction Z, which can ensure the consistency of the gas flow velocity through the heat dissipation gap 4 and improve the uniformity of heat dissipation to the intermediate plates 111 on both sides at each heat dissipation gap 4.

[0038] Based on this, in the arched part 2, the intermediate plates 111 are arranged at equal intervals, which can further improve the heat dissipation uniformity of each intermediate plate 111. Furthermore, based on the regularity of the heat dissipation gaps 4, it is also convenient to calculate the heat dissipation capacity of the copper busbar.

[0039] In some embodiments, the copper busbar includes one or at least two copper busbar units 7 arranged sequentially along the second direction X. For example... Figure 1 and Figure 6 As shown, a copper busbar unit 7 includes an arched portion 2 and two fixing portions 3 respectively disposed on both sides of the arched portion 2 in the second direction X. When the copper busbar is a long-distance structure, by arranging multiple copper busbar units 7 in an array, multiple arched portions 2 with good heat dissipation can be provided accordingly, ensuring the overall heat dissipation effect of the copper busbar.

[0040] Specifically, such as Figure 3 and Figure 4 As shown, the copper foil 1 includes a bent section 11 and two connecting sections 12 respectively located on both sides of the bent section 11 in the second direction X. The connecting sections 12 on the same side of each bent section 11 in the same arched portion 2 are respectively aligned and welded together along the first direction Z to form a fixing part 3. At least one fixing part 3 (e.g., the fixing parts 3 at both ends of the copper busbar in the second direction X) can be used to connect to external electrical equipment.

[0041] Specifically, the fixing method between the connecting segments 12 of the fixing part 3 is welding, such as diffusion welding. By welding the connecting segments 12 in the fixing part 3 into one piece through diffusion welding, a rigid fixing part with a dense structure and excellent electrical conductivity can be formed.

[0042] Specifically, when multiple copper busbar units 7 are sequentially arranged in the second direction X, the number of copper busbar units 7 can be selected according to the actual engineering conditions to adapt to copper busbars of different structural sizes and meet the overall engineering length requirements. In this case, a single arched portion 2 has good deflection, the entire long copper busbar has good strength, and the entire copper busbar contains multiple arched portions 2 for heat dissipation, thus possessing good heat dissipation capacity. For example... Figure 6 In the middle, four copper busbar units 7 are arranged sequentially in the second direction X. Two, three, etc. can also be arranged. It should be noted that the fixing part 3 between the arched part 2 of two copper busbar units 7 can be regarded as the two copper busbar units 7 sharing one fixing part 3, or the two fixing parts 3 of the two copper busbar units 7 can be connected along the second direction X.

[0043] In addition, according to the fixed installation requirements of the copper busbar, a fixed through hole 31 in the first direction Z can be provided on multiple fixed parts 3 respectively. The fixed through hole 31 can be used as a fixed point to fix and connect with other equipment.

[0044] Furthermore, each arched portion 2 of the copper busbar can protrude towards the same side in the first direction Z (the arched portion 2 and the bent section 11 constituting the arched portion 2 protrude in the same direction), such as Figure 6In the example where the first direction Z is the vertical direction, each arched part 2 protrudes upwards; in other embodiments, the protrusion direction of each arched part 2 in the first direction Z may not be exactly the same.

[0045] Furthermore, such as Figure 4 and Figure 5 As shown, the intermediate plate 111 has heat dissipation holes 13 extending along the first direction Z. The heat dissipation holes 13 are formed by drilling holes in the copper foil 1. Based on the arrangement of the heat dissipation holes 13, airflow can flow up and down, which is conducive to the rapid discharge of hot air from each heat dissipation gap 4.

[0046] Optionally, the heat dissipation holes 13 of each intermediate plate 111 in the arched portion 2 can be aligned and connected along the first direction Z to facilitate processing.

[0047] Alternatively, in the arched portion 2, the heat dissipation holes 13 on the intermediate plate 111 of the adjacent copper foil layers 1 are at least partially staggered, that is, not collinear in the first direction Z, so that when the airflow flows up and down, the airflow can pass through the heat dissipation holes 13 that are not collinear in the first direction Z, which can increase the contact area between this part of the airflow and the intermediate plate 111.

[0048] For example, in the arched portion 2, on the intermediate plate 111 of the adjacent copper foil layers 1, each intermediate plate 111 is provided with multiple rows of heat dissipation holes 13 along the second direction X (e.g. Figure 5 The three columns are equal in number and aligned in the first direction Z; at each column position, the number of heat dissipation holes 13 on the two intermediate plates 111 are different and partially staggered, for example... Figure 5 The top two middle plates 111 are plate one and plate two, respectively. In the first and third columns, plate one has 3 heat dissipation holes 13 and plate two has 2 heat dissipation holes 13. The heat dissipation hole 13 in the middle of plate one is not collinear with the heat dissipation holes 13 of plate two along the first direction X. The remaining 2 heat dissipation holes 13 are collinear with the two heat dissipation holes 13 of plate two along the first direction Z and are connected. In the second column, plate one has 2 heat dissipation holes 13 and plate two has 3 heat dissipation holes 13. The heat dissipation hole 13 in the middle of plate two is not collinear with the heat dissipation holes 13 of plate one along the first direction X. The remaining 2 heat dissipation holes 13 are collinear with the two heat dissipation holes 13 of plate one along the first direction Z and are connected.

[0049] In this embodiment, the copper busbar employs a multi-layer copper foil stacking scheme. The multi-layer bending sections 11 of the arched portion 2 maintain the relative distance between the copper foils 1, ensuring that the surface of each layer of copper foil 1 in the arched portion 2 is in direct contact with the air. Holes are opened in the stacked copper foils 1, allowing air to circulate naturally through the heat dissipation gaps 4 between the layers. This significantly increases the heat exchange area between the copper busbar and the air, improving heat dissipation efficiency and enabling it to carry a larger current with the same cross-sectional area. Simultaneously, multiple copper busbar units 7 can be arrayed to adapt to the current-carrying requirements of structures of different lengths. In this case, the arched portion 2 has good lateral strength, ensuring good deflection support over long distances. Furthermore, the long copper busbar has multiple arched portions 2 as heat dissipation structures, accommodating the passage of large currents.

[0050] In addition to the copper busbars mentioned above, the present invention also provides a copper busbar processing mold for processing copper busbars composed of stacked copper foils 1, such as the copper busbars in the above embodiments. When processing the copper busbar composed of stacked copper foils 1, each copper foil 1 can be stamped and then welded together. The copper busbar processing mold in the embodiments of this application can realize the steps of stamping and stacking copper foils 1.

[0051] Please refer to Figures 7 to 20 The copper busbar processing mold includes a concave mold assembly and a convex mold assembly.

[0052] The die assembly includes a die 5 and guide pillars 54. The die 5 includes multiple cavities 51 arranged sequentially and connected along a preset direction G, along one direction of the preset direction G (e.g., along a predetermined direction G). Figure 8 From right to left, the depth of the bottom surface 512 of each cavity 51 gradually increases, and the cavity 51 with the largest bottom surface 512 depth is the first cavity 511. The guide post 54 is fixed to the die 5 and is used to guide the reciprocating stroke of the punch 6 of the punch assembly.

[0053] The punch assembly includes a punch 6, a push module 64, an ejector pin 63, and other structures. The punch 6 is used to punch the flat copper foil raw material 8 placed on each cavity 51 to form copper foil 1 with bending sections 11. The push module 64 cooperates with an external cylinder to complete the reciprocating stroke of the punch 6 relative to the die 5. The punch 6 is provided with guide holes 65 that slide with the guide posts 54. Optionally, the die 5 is provided with four guide posts 54 that slide with four guide holes 65.

[0054] Among them, each copper foil 1 is stamped and formed, such as Figure 19 and Figure 20 As shown, the depth direction H of the cavity 51 is completely staggered, and each copper foil 1 can slide along the preset direction G to the first cavity 511 and automatically form a structure in which the concave mold 5 is stacked in the depth direction H.

[0055] In this type of copper busbar processing mold, after each copper foil raw material 8 is stamped by the punch 6 and the die 5 to form a copper foil 1 with a bending section 11, based on the depth relationship between the cavities 51, each copper foil 1 can slide to the side of the first cavity 511 with the largest depth on the bottom surface 512 of the cavity, realizing automatic unloading of the copper foil 1, and directly forming a stacked arrangement structure in the die 5 that meets the design requirements. This can reduce the difficulty of arranging the copper foil 1, reduce the difficulty of copper busbar processing, and improve the forming efficiency of copper busbar.

[0056] In some embodiments, such as Figure 19 and Figure 20 As shown, the die 5 is also provided with a receiving groove 53, which is located on the side of the first cavity 511 away from the other cavities 51 in a preset direction G. The receiving groove 53 is used to receive one end of the copper foil 1 of all the other cavities 51 except the first cavity 511 in the preset direction G.

[0057] After each copper foil 1 is formed and the punch 6 returns, the die 5 is tilted so that each cavity 51 is higher than the receiving groove 53. Except for the first cavity 511, one end of the copper foil 1 in each of the other cavities 51 falls into the receiving groove 53 and is stacked with the copper foil 1 in the first cavity 511 in sequence. The receiving groove 53 can position the copper foil 1 inserted into it in the depth direction H (perpendicular to the preset direction G) of the die 5, so as to prevent the copper foil 1 from flipping over at will.

[0058] In some embodiments, such as Figures 10 to 12 As shown, each cavity 51 extends in the same direction (perpendicular to the depth direction H and the preset direction G of the die 5), and each end of the die 5 in the extension direction of each cavity 51 is provided with a feeding groove 52. The feeding groove 52 is used for inserting the copper foil raw material 8 into the corresponding cavity 51, so that the straight copper foil raw material 8 can accurately enter the corresponding cavity 51, and the two ends of the copper foil raw material 8 rest in the corresponding feeding groove 52. Reference Figure 12 Five copper foil raw materials 8 enter five mold cavities 51 one by one through five feeding channels 52.

[0059] In addition, such as Figure 14 and Figure 15 As shown, the punch 6 is also provided with a slit 62 to cut off the portion of the copper foil raw material 8 located in the feeding groove 52 and the portion in the cavity 51 during the stamping process. After the copper foil raw material 8 is stamped into copper foil 1, both ends will be cut off from the slit 62 of the punch 6, ensuring that the copper foil 1 in the cavity 51 can slide smoothly into the receiving groove 53.

[0060] In some embodiments, such as Figures 16 to 18As shown, the punch 6 includes multiple working ends 61 arranged sequentially along a preset direction G, specifically equal to the number of cavities. After the punch 6 extends into the die 5 along the depth direction H of the die 5, each working end 61 is used to punch each copper foil material 8 in a corresponding manner, so that each copper foil material 8 simultaneously forms a copper foil 1 with a bending section 11.

[0061] Since the punch 6 has multiple working ends 61 that cooperate with each cavity 51, multiple copper foils 1 can be formed simultaneously. Compared with the copper foils 1 in each cavity 51 being stamped one by one, multiple copper foils 1 can be stamped quickly, improving processing efficiency.

[0062] Each working end 61 is used to cooperate with each cavity 51 of different depths to stamp copper foil raw material 8 of the same or approximately the same thickness. The forming working surface 611 of each working end 61 for contacting and stamping copper foil raw material 8 also gradually increases in height along one direction of the preset direction G. The height direction of the forming working surface 611 is consistent with the depth direction H of the die 5. The working end 61 with the largest protrusion of the forming working surface 611 is engaged with the first cavity 511.

[0063] In addition, the shapes of the cavity bottom surface 512 of the cavity 51 and the forming working surface 611 of the working end 61 are determined according to the shape of the bent end on the copper foil 1 to be formed.

[0064] For example, when the bending segment 11 is a trapezoidal groove structure with an open bottom as described in the above embodiment, refer to Figure 7 The bottom surface 512 of cavity 51 is a matching trapezoidal groove, as shown in the reference. Figure 14 The forming working surface 611 of the working end 61 is a trapezoidal protrusion. Under the clamping of the trapezoidal protrusion and the trapezoidal groove, the flat copper foil raw material 8 is stamped into a bent section 11 with a trapezoidal groove structure with an open bottom.

[0065] Alternatively, when the bending section 11 is replaced with an arc-shaped section, i.e. used to stamp copper foil 1 with an arc-shaped section, the bottom surface 512 of the cavity 51 is set as a matching arc-shaped groove, and the forming working surface 611 of the working end 61 is set as a matching arc-shaped protrusion.

[0066] In some embodiments, the forming working surface 611 of the punch 6 is provided with protrusions, and the bottom surface 512 of the cavity of the die 5 is provided with concave points. The protrusions and concave points cooperate to directly punch heat dissipation holes 13 on the copper foil raw material 8, further improving the processing efficiency of the copper foil 1. In other embodiments, the heat dissipation holes 13 can also be punched after the copper foil 1 has been formed by bending the section, demolded from the die 5, or after welding.

[0067] For clarity, please refer to the following: Figures 8 to 20The example has 5 cavities 51 and 5 working ends 61, which are used to process 5 copper foil raw materials 8 into 5 copper foils 1.

[0068] The die 5 can be inclined relative to the ground, for example, at 45°, and the first cavity 511 in the cavity 51 is the lowest. Figure 12 As shown, five copper foil raw materials 8 enter the five cavities 51 one by one through the corresponding feeding channels 52 on one side of the five cavities 51, and the two ends of each copper foil raw material 8 are respectively located in the feeding channels 52 at both ends of the corresponding cavity 51, ensuring that the copper foil 1 does not slip off before stamping.

[0069] The guide hole 65 of the punch 6 is fitted onto the guide post 54 of the die 5, and slides along the guide post 54 to complete the reciprocating stroke, realizing mold closing and return. Figure 17 and Figure 18 As shown, during the contact stroke of the concave die 5 and the convex die 6, the pushing module 64 pushes the convex die 6 towards the concave die 5, and the copper foil raw material 8 is stamped into a specified shape and cut by the cut 62 of the convex die 6, thus forming the copper foil 1. When the copper foil 1 has heat dissipation holes 13, it can be directly stamped and formed by the cooperation of the protrusions on the forming working surface 611 of the convex die 6 and the concave points on the bottom surface 512 of the cavity of the concave die 5, so that the heat dissipation holes 13 can be formed simultaneously with the forming of the bending section 11.

[0070] Die 5 and punch 6 as follows Figure 19 and Figure 20 The copper foil 1 is placed in an inclined manner, and after being cut, it slides into the receiving groove 53 of the die 5 under the action of gravity along the inclined direction of the die 5. Among them, for each cavity 51 of the bottom surface 512 from deep to shallow, the arch of the bending section 11 of each copper foil 1 decreases from large to small. The closer to the first cavity, the earlier it slides into the receiving groove 53. The copper foils are stacked in order of decreasing arch of the bending section 11. After each copper foil 1 except the first cavity 511 slides into the receiving groove 53 and is aligned, all copper foils 1 are automatically stacked. After being picked up by the operator, they can be directly welded.

[0071] In addition, the present invention also provides a method for calculating the heat dissipation capacity of copper busbars, which can be specifically applied to the copper busbars provided in the above embodiments.

[0072] The method includes the following steps: S1: Establish the thermal balance determination conditions for the copper busbar.

[0073] Specifically, the heat balance formula is: Heating power =Heat dissipation power

[0074] Both the heating power and the heat dissipation power are functions of the copper busbar temperature.

[0075] In engineering, when the deviation between heat generation power and heat dissipation power is within a certain range, thermal equilibrium can be considered achieved. Accordingly, the criteria for determining thermal equilibrium are: |Heating power - Heat dissipation power |≤ Allowable tolerance

[0076] Among them, allowable tolerance >0, for example =0.001.

[0077] S2: Solve for the thermal equilibrium temperature of the copper busbar that satisfies the thermal equilibrium criterion.

[0078] By using this calculation method, staff can obtain the current thermal equilibrium temperature of the copper busbar, thus clarifying its heat dissipation capacity and improving the safety of copper busbar applications.

[0079] In some embodiments, heating power In the calculation:

[0080] In the formula: I represents the current flowing through the copper busbar; T0 is the selected reference temperature (°C); The resistance of the copper busbar at temperature T0 (°C); α is the temperature coefficient of resistance. Taking copper foil as an example, the temperature coefficient of resistance α is taken as 0.00393. T is the thermal equilibrium temperature (°C) to be calculated.

[0081] It should be noted that the copper busbar is made of copper, which is an isotropic material with a high thermal conductivity. The internal thermal resistance of the copper busbar is much smaller than the surface thermal resistance. Under steady state, the internal temperature difference is extremely small. In engineering calculations, the temperature of the copper busbar can be approximated as uniform, and the calculated result T is its average temperature.

[0082] Based on the above formula for heat generation power, and by adjusting the resistance according to temperature changes, the accuracy of thermal equilibrium temperature calculation can be improved.

[0083] Furthermore, the copper busbar adopts a relatively regular structure, with each layer of copper foil material being isotropic. See details for further information. Figures 1 to 5 In the second direction X, the copper foil 1 has connecting sections 12 on both sides of each bent section 11. On each copper foil 1, the connecting sections 12 on both sides of the bent section 11 are respectively aligned and fixed along the first direction Z, so that each arched portion 2 forms a fixing portion 3 formed by connecting sections 12 on both sides in the second direction X. One arched portion 2 and its adjacent fixing portions 3 on both sides constitute a copper busbar unit 7. Figure 1 It has one copper busbar unit 7, Figure 6 There are multiple copper busbar units 7, specifically 4. When there are multiple copper busbar units 7 in the copper busbar, the heat dissipation capacity of each copper busbar unit 7 can be calculated sequentially.

[0084] The bending section 11 is a trapezoidal groove structure with an open bottom. The middle plate 111 corresponds to the upper bottom plate, and the two side plates 112 correspond to the two waist plates. The middle plate 111 is a flat plate perpendicular to the first direction Z. In the arched section 2: the middle plates 111 are arranged at equal intervals; the side plates 112 are flat plates, and the side plates 112 are fitted together. For ease of calculation, heat dissipation can be calculated as a single surface, and heat generation can be calculated as parallel.

[0085] Based on this, refer to Figures 21 to 23 Define the dimensions of the structure in a copper busbar unit 7: Thickness t at various points on copper foil 1; In the first direction Z: the copper busbar includes n layers (n≥2 and a positive integer) of copper foil 1 with bent sections stacked along the first direction Z (corresponding to the up and down direction); the height difference between the two end faces of the copper busbar unit 7 is H ( Figure 21 (Height difference between the top surface of the top copper foil 1 intermediate plate 111 and the bottom surface of the connecting section 12 of the bottom copper foil 1 in the orientation).

[0086] Second direction X: Each layer of copper foil is 1 length L (along the second direction X).

[0087] In the third direction Y: each layer of copper foil has a width w (along the third direction Y).

[0088] At the connection section 12 of each copper foil layer, such as Figure 23 As shown, the flat connecting segment 12 is perpendicular to the first direction Z. The thickness of the connecting segment 12 is along the first direction Z, and the thickness t is equal to the copper foil thickness t. The length is along the second direction X, and the length is Lw. In the fixing part 3 formed by each layer of connecting segments 12, each connecting segment 12 is welded and compacted to form an integral welding area. The thickness of the copper foil 1 remains unchanged after welding, and there is no gap for heat dissipation at the welding point. When calculating the thickness of a single copper foil 1, the heat dissipation of the middle layer connecting segment 12 in the thickness direction can be ignored.

[0089] In the bending section 11 of each layer of copper foil, as... Figure 21 and Figure 22 As shown, the bent section 11 is located in the middle of the copper busbar unit 7 in the second direction X, within a length region La = L - 2Lw. The cross-section of the bent section 11 perpendicular to the third direction Y is a trapezoidal cross-section. The intermediate plate 111 in the bent section 11 is flat and perpendicular to the first direction Z, as shown... Figure 22 As shown, the heat dissipation gap 4 between adjacent intermediate plates 111 has a spacing dg in the first direction Z (the spacing between the end faces of adjacent intermediate plates 111 that are close to each other in the first direction Z, as referenced). Figure 21 and Figure 22 dg is the vertical distance between the lower surface of the upper intermediate plate 111 and the upper surface of the lower intermediate plate 111 in adjacent intermediate plates 111. In this embodiment, dg is between 1-2 mm.

[0090] Furthermore, when calculating the heating power, the current path length of the copper busbar unit 7 can be calculated first, and then the resistance of the copper busbar unit 7 can be obtained.

[0091] In the fixing part 3, the connecting segments 12 of each layer are tightly fitted together, and the height of the i-th connecting segment 12 (that is, the height of the upper surface of the i-th connecting segment 12 from the reference plane O, where the reference plane O is the lower surface of the bottom connecting segment 12) is:

[0092] Where 1≤i≤n and are positive integers, i =1 is the top layer and i =n is the bottom layer.

[0093] In the arched portion 2, the heat dissipation gap 4 between adjacent intermediate plates 111 is at a height dg in the first direction Z, the height of the top surface of the top intermediate plate 111 is H (the distance of the intermediate plate 111 relative to the reference plane O), and the height of the top surface of the i-th intermediate plate 111 is: ,

[0094] Solving for:

[0095] The arch height of the i-th layer bending segment (the height difference between the top surface of the i-th layer intermediate plate 111 and the height of the i-th layer connecting segment 12):

[0096] Therefore, in the calculation of current path length: Trapezoidal arched section 2, length of the top bottom of each layer of bent section 11 (Length of the i-th layer intermediate plate 111 along the second direction X), bottom length b of the lowest layer bending segment 11, and waist length of the i-th layer bending segment 11:

[0097] Length of bent section 11 unfolded:

[0098] Resistance of single-layer bent section 11 (T0℃=20℃):

[0099] in: Let be the resistivity of copper at 20℃, and take . ; This refers to the cross-section of the bent section of the copper foil perpendicular to its extension direction. The width of copper foil 1 (third direction Y); t is the thickness of copper foil 1.

[0100] Each layer of copper foil in its bent section (including the middle plate 111 and the side plate 112) can be considered as connected in parallel. The parallel resistance at 20°C is:

[0101] In the fixing part 3, the connecting sections 12 of each layer are welded together as one piece. The total resistance of a single fixing part 3 at 20°C is:

[0102] in: Let be the resistivity of copper at 20℃, and take . ; The cross-section of the fixing part 3 formed by the n-layer connecting segment 12 in a direction perpendicular to its extension; The width of copper foil 1 (third direction Y); nt is the thickness of the nth layer of copper foil 1.

[0103] The total resistance at any temperature T℃ is:

[0104] In the formula: Let be the temperature coefficient of resistance, and take . ; Based on the total resistance above, and by obtaining the current I, the heating power can be calculated as follows:

[0105] In some embodiments, when calculating the heat dissipation power, heat dissipation is divided into two aspects: natural convection heat dissipation and radiation heat dissipation. The heat dissipation power is:

[0106] j represents different surface partitions of the copper busbar under natural convection; : j-zone area; : Natural convection heat transfer coefficient in region j; p represents different surface partitions under radiative heat dissipation; :p partition area; : Radiation heat transfer coefficient in region p; Ambient temperature: Typically, the ambient temperature is between 20-50℃.

[0107] In solving for the thermal equilibrium temperature, an iterative method can be used, with the convergence condition being:

[0108] Regarding natural convection heat transfer, the heat transfer coefficient of the outer surface of the copper foil varies with different orientations under natural convection conditions. To simplify calculations, this invention employs the partitioned equivalent heat transfer coefficient method.

[0109] (1) The top surface of the copper busbar in the first natural convection section includes the top surface of the bent section 11 of the top copper foil and the top surface of the two connecting sections 12: Heat transfer coefficient of this zone:

[0110] Area of ​​this partition:

[0111] (2) The bottom surface of the copper busbar in the second natural convection lower zone includes the bottom surface of the bent section 11 of the bottom copper foil and the bottom surface of the two connecting sections 12, as well as the surrounding surface of each heat dissipation gap 4 of the arched part 2. The rising hot air in this part will be hindered by itself or the adjacent upper copper foil 1, so the coefficient is smaller than that in the first natural convection lower zone: Heat transfer coefficient of this zone:

[0112] Area of ​​this partition:

[0113] in, The area of ​​the bottom surface of the top intermediate plate 111. Let be the sum of the areas of the top and bottom surfaces of the intermediate plate 111 from the 2nd to the nth layer. The total exposed area of ​​the lower side plates 112 on both sides of each layer of the arched section 2, where the curved sections 11 are bent. The total area of ​​the bottom surfaces of the two fixed parts 3; (3) The third natural convection lower section, all sides of the arched part 2 and the two fixed parts 3: Heat transfer coefficient of this zone: ,

[0114] Area of ​​this partition:

[0115] in, The total area of ​​the two sides of the arched part 2. The total area of ​​a single fixed part 3 at one end in the third direction Y. The total area of ​​a single fixed part 3 at one end in the second direction X; In the calculation of the above coefficients: Gr: Grashof number,

[0116] g: acceleration due to gravity;

[0117] β: Coefficient of fluid volume expansion; Temperature difference between the wall and the fluid; Characteristic length (height is taken in the third natural convection zone; perimeter / area is taken in the first and second natural convection zones). : fluid kinematic viscosity; Pr: Prandtl number; λ: Thermal conductivity of air.

[0118] At this point, natural convection heat transfer has three zones:

[0119] In terms of radiative heat transfer, the linearized approximation of the radiative heat transfer coefficient is as follows:

[0120] in: Surface emissivity; T: The thermal equilibrium temperature to be calculated; Ambient temperature; Above and below the heat dissipation gap 4 of the arched portion 2, the upper and lower surfaces of the copper foil 1 face each other and radiate to each other, which is equivalent to radiation shielding. However, the area of ​​the side of the copper busbar is small and accounts for a small proportion of the total area of ​​the copper busbar. In this embodiment, the radiation heat transfer from the side of the copper busbar to the air is ignored. The top and bottom surfaces of the copper busbar can be used as unshielded surfaces and as the area for radiation heat dissipation.

[0121] in, The area of ​​the upper surface of the top bending section 11 is given. The area of ​​the lower surface of the bottom bending section 11 is given. The area of ​​the top surface and the area of ​​the bottom surface of a single fixed part.

[0122] At this point, the radiative heat transfer has three zones:

[0123] In a specific example, the calculation process is as follows: 1. Obtain the structural parameters n, t, w, L. , (i=1 to n), b, H, dg, material parameters , , Operating condition parameter I ; 2. Calculate the height of the fixed part. ; 3. Calculate the height of the vault: ; 4. Calculate the length of the 11 trapezoidal legs in each bending segment: , unfolded length ; 5. Calculate the total resistance at any temperature T℃:

[0124] 6. Calculate the natural convection heat transfer coefficient and area of ​​the first, second, and third natural convection zones; 7. Calculate the radiative heat transfer coefficient and area; 8. Set an initial temperature T, and iteratively solve for the thermal equilibrium condition until convergence:

[0125] 9. Output equilibrium temperature T and temperature rise .

[0126] It should be noted that when an element is referred to as "fixing" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as "connecting" another element, it can be directly connected to the other element or there may be an intervening element. Furthermore, in the description of this invention, unless otherwise stated, "multiple," "multiple roots," and "multiple groups" mean two or more.

[0127] The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0128] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0129] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0130] The copper busbar, copper busbar processing mold, and copper busbar heat dissipation capacity calculation method provided by this invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principles of this invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A copper busbar processing mold, characterized in that, For forming a copper busbar, the copper busbar includes at least two layers of copper foil (1) stacked along a first direction Z, each of the copper foils (1) including a bent section (11) protruding on the same side facing the first direction Z; between two adjacent bent sections (11) along the first direction Z, one bent section (11) extends into the recessed space of the other bent section (11), so that all the bent sections (11) arranged sequentially along the first direction Z form an arch (2). The bending section (11) includes a middle plate (111) and two side plates (112) located on both sides of the middle plate (111) in the second direction X. In the first direction Z, the two side plates (112) are located on the same side of the middle plate (111) and have an angle with the middle plate (111) respectively. There is a heat dissipation gap (4) between two adjacent middle plates (111) in the first direction Z and through the third direction Y. The two adjacent side plates (112) in the first direction Z are correspondingly fitted together. Alternatively, the bending section (11) is an arc-shaped section. The copper busbar processing mold includes: The cavity (5) includes a plurality of cavities (51) arranged and connected in sequence along a preset direction (G). Along one direction of the preset direction (G), the depth of the bottom surface (512) of each cavity (51) gradually increases, and the cavity (51) with the largest bottom surface (512) depth is the first cavity (511). A punch (6) is used to punch flat copper foil raw material (8) placed on each of the cavities (51) to form copper foil (1) having the bending section (11) respectively. After the copper foils (1) are stamped, they are completely staggered in the depth direction (H) of the cavity (51), and each copper foil (1) can slide along the preset direction (G) to the first cavity (511) and automatically form a structure of stacked arrangement in the depth direction (H).

2. The copper busbar processing mold according to claim 1, characterized in that, The die (5) is also provided with a receiving groove (53), which is located on the side of the first cavity (511) away from the other cavities (51) in the preset direction (G); The receiving trough (53) is used to receive one end of the copper foil (1) of all the other cavities (51) except the first cavity (511) in the preset direction (G).

3. The copper busbar processing mold according to claim 1, characterized in that, Each cavity (51) extends in the same direction, and the die (5) is provided with a feeding groove (52) at both ends of the extension direction of each cavity (51); the feeding groove (52) is used for the copper foil raw material (8) to be inserted into the corresponding cavity (51) through the feeding groove (52), and the two ends of the copper foil raw material (8) are respectively placed in the corresponding feeding groove (52); The punch (6) is also provided with a cut (62) to cut off the portion of the copper foil raw material (8) located in the feeding channel (52) and the portion in the cavity (51) during the stamping process.

4. The copper busbar processing mold according to any one of claims 1 to 3, characterized in that, The punch (6) includes a plurality of working ends (61) arranged sequentially along the preset direction (G); after the punch (6) extends into the die (5) along the depth direction (H), each working end (61) is used to stamp each copper foil raw material (8) in a corresponding manner, so that each copper foil raw material (8) simultaneously forms the copper foil (1) with the bending section (11).

5. A copper busbar, characterized in that, The copper busbar processing mold according to any one of claims 1 to 4 is used during the processing; The copper busbar includes at least two layers of copper foil (1) stacked along the first direction Z, and each of the copper foils (1) includes a bent section (11) protruding toward the same side of the first direction Z. The bending section (11) includes a middle plate (111) and two side plates (112) located on both sides of the middle plate (111) in the second direction X. In the first direction Z, the two side plates (112) are located on the same side of the middle plate (111) and have an angle with the middle plate (111) respectively. Between two adjacent bending segments (11) along the first direction Z, one bending segment (11) extends into the recessed space of the other bending segment (11), thereby forming an arched portion (2) among all the bending segments (11) arranged sequentially along the first direction Z; there is a heat dissipation gap (4) between two adjacent intermediate plates (111) along the first direction Z, and the two adjacent side plates (112) along the first direction Z are correspondingly fitted together.

6. The copper busbar according to claim 5, characterized in that, The bending section (11) is a trapezoidal groove structure with an open bottom; wherein, the middle plate (111) is a plate corresponding to the upper bottom, and the two side plates (112) are plates corresponding to the two waists respectively.

7. The copper busbar according to claim 5, characterized in that, The intermediate plate (111) is a flat plate and is perpendicular to the first direction Z; the intermediate plates (111) in the arched portion (2) are arranged at equal intervals along the first direction Z.

8. The copper busbar according to claim 5, characterized in that, The intermediate plate (111) is provided with heat dissipation holes (13) that penetrate through the first direction Z.

9. The copper busbar according to any one of claims 5 to 8, characterized in that, It includes one or at least two copper busbar units (7) arranged sequentially along the second direction X. The copper busbar unit (7) includes one arched part (2) and two fixing parts (3) respectively provided on both sides of the arched part (2) in the second direction X. The copper foil (1) includes connecting sections (12) respectively disposed on both sides of the bent section (11) in the second direction X; the connecting sections (12) that are connected to each bent section (11) in the same arched part (2) are respectively welded and fixed one to one along the first direction Z to form a fixing part (3).

10. A method for calculating the heat dissipation capacity of a copper busbar, characterized in that, Applied to the copper busbar according to any one of claims 5 to 9; the method includes: The thermal balance judgment condition for the copper busbar is established as follows: |heating power - heat dissipation power| ≤ allowable tolerance, where the heating power and the heat dissipation power are both functions of the copper busbar temperature; Determine the thermal equilibrium temperature of the copper busbar that satisfies the aforementioned thermal equilibrium determination condition.

11. The method for calculating the heat dissipation capacity of a copper busbar according to claim 10, characterized in that, The heating power: In the formula: I: Current flowing through the copper busbar; T0: The selected reference temperature; Resistance of the copper busbar at temperature T0; α: Temperature coefficient of resistance; T: The thermal equilibrium temperature to be calculated.

12. The method for calculating the heat dissipation capacity of a copper busbar according to claim 10 or 11, characterized in that, The heat dissipation power is: j: Different surface partitions of the copper busbar under natural convection; : j-zone area; : Natural convection heat transfer coefficient in region j; p: Different surface partitions under radiative heat dissipation; :p partition area; : Radiation heat transfer coefficient in region p; T: The thermal equilibrium temperature to be calculated; Ambient temperature.

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