Novel low-cost busbar for capacitor

Abstract

The utility model discloses a novel low-cost busbar for a capacitor, which comprises a busbar body, an external mounting terminal part, a busbar flat plate part, a busbar side baffle plate part, a busbar flat plate cavity part and a core welding end part, and is characterized in that the busbar body is made of a composite metal material including a copper material; according to the busbar for the capacitor, the structure of the busbar for the capacitor is improved by utilizing the current skin effect of the electrical property, the over-current capability and the connection strength requirement of the busbar for the capacitor are ensured by utilizing the characteristic requirements of high melting point, high tensile strength and the like of a copper material, and the busbar for the capacitor has the advantages of greatly reducing the production cost, high efficiency and high reliability.

Description

Technical Field:

[0001] The utility model relates to the technical field of capacitor product production, in particular to a busbar structure of a capacitor for a new energy vehicle in the new energy field, that is, a busbar for a new type of low-cost capacitor. Background Art:

[0002] With the rapid development of power electronics technology, due to its own advantages such as high safety, long life, large ripple current resistance, and stable high-frequency performance, metallized film capacitors have been gradually widely used in the fields of new energy, automotive electronics, rail transit, industrial control, frequency conversion, etc. Especially in the field of new energy vehicles, the demand for film capacitors is increasing. However, the electromagnetic performance requirements for film capacitors in the new energy vehicle field are also high, resulting in the main use of pure copper busbar structures for the installation electrodes of film capacitors on current new energy vehicles.

[0003] A metallized film capacitor mainly consists of a core of non-inductive wound metallized film, a busbar, a plastic shell, and epoxy potting glue. Its main process is to parallelly weld the core to the solder joint position at the core welding end of the busbar, directly install it into the plastic shell, then fill it with epoxy potting glue, and encapsulate it through high-temperature curing, leaving the external installation terminal part of the busbar for performance testing and customer installation. Most of the busbars used in this production process are red copper, which are formed into the required structure by means of laser cutting or stamping. At the same time, to prevent copper from being oxidized by the environment, the surface of the copper busbar will be passivated or electroplated with a tin layer. However, at present, due to the increasing price of red copper year by year, it has become the main material cost of such metallized film capacitors, causing great pressure on the comprehensive manufacturing cost of such metallized film capacitors; continuous development is needed; how to invent a new busbar structure to replace the existing red copper busbar to reduce costs and at the same time meet the performance requirements of this type of metallized film capacitor has become the future development trend of this type of metallized film capacitor.

[0004] For example, in Chinese Patent Publication No. CN113963950A, the disclosed utility model is named "A Capacitor Busbar and a Capacitor". The present utility model provides a capacitor busbar and a capacitor. The capacitor busbar includes a main body and electrode terminals. The surface of the main body and the electrode terminals opposite to the end face electrode is the first surface, and the surface opposite to the first surface is the second surface. The electrode terminals extend from a specified edge of the main body in a direction orthogonal to the thickness direction of the main body. The electrode terminals have a bending portion and an extending portion. The first surface of the extending portion is adapted to be welded and attached to the end face electrode. The bending portion is located between the extending portion and the main body. The structure of the bending portion is bent and deformed from the specified edge of the main body in the thickness direction of the main body until the first surface of the extending portion is lower than the first surface of the main body. This can ensure the close fit between the electrode terminals and the end face electrode, reduce the contact resistance between the busbar and the core, reduce the risk of capacitance electrical parameter failure, ensure the moisture-proof performance of the capacitor, and avoid the situation of the busbar breaking during the capacitor manufacturing process.

[0005] Another example is Application Publication No.: CN113206352A, the utility model name is "A Capacitor Busbar for a New Energy Battery and Its Forming Method". The present utility model provides a capacitor busbar for a new energy battery, which includes a positive busbar and a negative busbar. A first installation groove is formed in the middle part of the negative busbar, and multiple capacitor elements can be installed. Multiple first welding parts are formed on the right side of the negative busbar, so that the capacitor elements can be fixed in the first installation groove through the first welding parts, which greatly facilitates the installation of the capacitor elements. In addition, the first negative terminal and the first positive terminal are in the same direction, making the cooperation between the first negative terminal and the first positive terminal more convenient. The fourth positive terminal and the fifth positive terminal are respectively welded to the second installation plate and the first installation plate alone, which greatly simplifies the forming process of the positive busbar. In addition, by wrapping insulating glue on the positive and negative terminals respectively, the insulation and service life of the positive and negative terminals are greatly improved.

[0006] The "New Energy Vehicle Capacitor Busbar and Its Production Method" disclosed in Publication No. CN110125260A of the application. The present utility model discloses a new energy vehicle capacitor busbar, which mainly consists of a connecting plate, a plurality of straight terminals, a plurality of U-shaped terminals and a plurality of direct insertion terminals that are connected and fixed to the connecting plate. The straight terminals and the U-shaped terminals are respectively fixed to the connecting plate by stamping and riveting along the opposite sides of the connecting plate, and the direct insertion terminals are arranged in the middle of the connecting plate and fixed to the connecting plate by laser welding. For the new energy vehicle capacitor busbar adopting the above technology, each terminal is fixedly connected to the connecting plate by stamping and riveting or laser welding, successfully realizing the joint without solder on the copper material. Since no solder is required, the whole becomes lightweight, and the external dimensions of the busbar can be greatly streamlined. It not only improves the firmness of the fixed connection, but also has high self-strength, high heat resistance, cold resistance and chemical tolerance, and will not deteriorate during long-term use, thus extending the service life of the busbar. etc.

[0007] As can be seen from the existing technical solutions disclosed above, the above technical solutions are improvements to the ordinary physical structure of the existing film capacitor busbar, and do not involve what materials are used for the copper busbar body. That is, the improved busbar structure can not only meet the performance requirements of the capacitor, but also greatly reduce the preparation cost of the capacitor busbar structure. That is, on the premise of ensuring the capacitor busbar body structure with the strength performance of the copper busbar structure, how to use the current skin effect of electrical performance to improve the capacitor busbar structure, and at the same time achieve the purpose of meeting the technical effect requirements of the current transfer of the metallized film capacitor.

[0008] Therefore, how to provide a new type of low-cost capacitor busbar structure, which can meet the strength requirements of the busbar structure of the metallized film capacitor in the new energy field through technological innovation of the busbar structure materials for the metallized film capacitor. That is, the existing copper material is used as the base material of the capacitor busbar structure, and the characteristics such as high melting point and high tensile strength of the copper material are utilized to ensure the over-current capacity and connection strength requirements of the capacitor busbar. By using other metals combined with copper material as the busbar base material, the above performance requirements of the capacitor busbar are better met. While ensuring the product performance, it can greatly reduce the cost, and has the advantages of low cost, high efficiency and high reliability. It improves the comprehensive performance of the film capacitor; achieves the purpose of cost reduction and emission reduction. Summary of the utility model:

[0009] A novel low-cost busbar for capacitors disclosed by the utility model includes a busbar body, an external installation terminal part, a busbar flat plate part, a busbar side baffle part, a busbar flat plate cavity part, and a core welding end part. The busbar flat plate part and the busbar side baffle part of the busbar body are made of a composite metal material including copper material. The structure of the capacitor busbar is improved by utilizing the current skin effect of electrical properties. By using the characteristics of high melting point and high tensile strength of copper material, the over-current capacity and connection strength requirements of the capacitor busbar are ensured, and it has the advantages of low cost, high efficiency, and high reliability. The comprehensive performance of the thin-film capacitor is improved; the purpose of cost reduction and emission reduction is achieved.

[0010] A novel low-cost busbar for capacitors provided by the utility model, the busbar includes a busbar body and an external installation terminal. The busbar body includes a busbar flat plate part and a busbar side baffle part. The busbar side baffle part is arranged at a corresponding position on one side edge of the busbar flat plate part. One end of the external installation terminal part is connected to the corresponding position of the busbar side baffle part; several busbar flat plate cavity parts are arranged on the surface of the busbar flat plate part, and a core welding end part is arranged in each inner cavity of the busbar flat plate cavity part; the busbar flat plate part and the busbar side baffle part of the busbar body are made of a composite metal material.

[0011] For the novel low-cost busbar for capacitors, the composite metal material is composed of copper material and aluminum material; the aluminum material is controlled as the aluminum substrate layer for preparing the busbar body, and the copper material is the surface copper layer, and the surface copper layer is controlled to uniformly cover the outer wall surface of the aluminum substrate layer.

[0012] For the novel low-cost busbar for capacitors, which is the composite metal material constituting the busbar body, the thickness ratio relationship between the aluminum substrate layer and the surface copper layer covering the outer wall surface of the aluminum substrate layer is calculated according to the principle of the current skin effect of the metal material to ensure the over-current capacity of the busbar structure; the specific method and formula are as follows:

[0013] The resistance of the pure copper busbar is calculated according to the following formula:

[0014]

[0015] r_copper busbar -- the resistance of the copper busbar, that is, the resistance of the pure copper busbar,

[0016] ρ 铜 -- the resistivity of copper (Ω·m),

[0017] L -- the length of the busbar (m),

[0018] D -- the width of the busbar (m),

[0019] d 铜 -- the thickness of copper (m);

[0020] However, when designing with the thickness of the aluminum substrate layer 201, to ensure that the resistance of the aluminum substrate layer 201 corresponds to the resistance of the pure copper busbar, the following calculation formula is satisfied:

[0021]

[0022] d 铝 - Thickness of aluminum (m),

[0023] r 铜排 -- Resistance of copper busbar (Ω),

[0024] ρ 铝 -- Resistivity of aluminum (Ω·m),

[0025] L - Length of busbar (m),

[0026] D - Width of busbar (m);

[0027] Substitute the calculation formula (1) into the calculation formula (2) of the aluminum layer thickness to obtain the following calculation formula (3):

[0028]

[0029] d 铝 - Thickness of aluminum (m),

[0030] d 铜 - Thickness of copper (m),

[0031] ρ 铜 -- Resistivity of copper (Ω·m),

[0032] ρ 铝 -- Resistivity of aluminum (Ω·m).

[0033] For the described novel low - cost capacitor busbar, the thickness of the busbar body made of pure copper material is 1 - 3 mm, and the corresponding surface copper layer is evenly coated on the outer wall surface of the aluminum substrate layer around the circumference to make the busbar body of the corresponding specification, controlling the thickness of the surface copper layer: the thickness of the aluminum substrate layer = 0.1 - 0.14 mm: 1.6 - 4.8 mm.

[0034] For the described novel low - cost capacitor busbar, when the thickness of the busbar body made of pure copper material is 1 mm, the corresponding surface copper layer is evenly coated on the outer wall surface of the aluminum substrate layer around the circumference to make the busbar body of the same specification, controlling the thickness of the surface copper layer: the thickness of the aluminum substrate layer = 0.1 mm: 1.6 mm.

[0035] Preferably, when the thickness of the busbar body made of pure copper material is 2 mm, the corresponding surface copper layer is evenly coated on the outer wall surface of the aluminum substrate layer to form a busbar body of the same specification, and the thickness of the surface copper layer: the thickness of the aluminum substrate layer = 0.1 mm: 3.21 mm.

[0036] For the novel low-cost capacitor busbar described above, when the thickness of the busbar body made of pure copper material is 3 mm, the corresponding surface copper layer is evenly coated on the outer wall surface of the aluminum substrate layer to form a busbar body of the same specification, and the thickness of its surface copper layer: the thickness of the aluminum substrate layer = 0.1 mm: 4.8 mm.

[0037] For the novel low-cost capacitor busbar described above, its external mounting terminal part and the core welding end part are made of pure copper material; the external mounting terminal part is set as an inverted U-shaped structure, and one side of the inverted U-shaped structure is connected to the corresponding position of the busbar side baffle part.

[0038] The novel low-cost capacitor busbar disclosed by the present utility model is aimed at the fact that the special busbar for the current metallized film capacitor mainly uses purple copper material and is made by laser cutting, die stamping, welding, and surface treatment. However, with this current technology, its main disadvantage is that the cost of the capacitor busbar prepared with all pure copper or all purple copper material is relatively high, and it can no longer meet the customer's demand for busbar cost control. Therefore, it is urgent to use composite metal materials to replace pure purple copper or pure copper busbar or copper busbar structure. However, which metal materials should be used for compounding to meet the above cost reduction requirements and at the same time ensure that when used as the busbar of the metallized film capacitor, it will not cause excessive current and overheating due to different resistances and electrical conductivity, resulting in the aging of the metallized film capacitor using this busbar, or the melting of the inner core of the metallized film due to the overheating of the busbar.

[0039] The novel low-cost capacitor busbar disclosed by the present utility model utilizes the skin effect principle. When there is alternating current or alternating electromagnetic field in the conductor, the current is concentrated in the thin layer on the outer surface of the conductor, that is, the "skin" part, resulting in the maximum current density near the surface of the conductor and smaller current inside the conductor. This phenomenon increases the resistance of the conductor and also increases the power loss. By using copper-aluminum compound and calculating the resistance of the pure copper busbar, the thickness ratio relationship between the aluminum substrate layer 201 and the surface copper layer 202 is determined to prepare a capacitor busbar that, under different capacitor capacities and different busbar specifications, will not cause damage to the capacitor due to overheating, thus affecting its use. As shown in Table 1 below, aluminum is used as the base material because the density of aluminum is lower than that of copper. As shown in Table 1 below,

[0040]

[0041] Explanation: For the same volume of the busbar, aluminum is lighter in specific weight, and at the same time, the price of aluminum is much lower than that of copper. With the above structure of the present utility model, the copper material layer 202 is coated on the aluminum substrate layer 201. For the prepared capacitor busbar or the capacitor busbar structure, its cost will be significantly reduced by more than 25 - 40% based on the current price. At the same time, the overcurrent capacity of the busbar is preferably retained, that is, it can meet the quality requirements of the same specification busbar products made of pure copper materials while the preparation cost can be significantly reduced. Brief Description of the Drawings:

[0042] Figure 1 , is a schematic structural diagram of a novel low-cost capacitor busbar for the utility model,

[0043] Figure 2 , is Figure 1 a front view structural diagram,

[0044] Figure 3 , is Figure 2 a sectional structural diagram along the A - A direction;

[0045] Figure 4 , is for Example 1 of the present utility model. The copper plating layer or the surface copper material layer 202 with different thicknesses coated on the aluminum substrate layer 201 with a thickness of 1.6 mm is used to prepare a temperature rise trend diagram of a 300 μF capacitor product, that is, a temperature rise comparison diagram compared with a pure copper busbar with a thickness of 1 mm;

[0046] Figure 5 , is for Example 2 of the present utility model. The copper plating layer or the surface copper material layer 202 with different thicknesses coated on the aluminum substrate layer 201 with a thickness of 3.21 mm is used to prepare a temperature rise trend diagram of a 300 μF capacitor product; a temperature rise comparison diagram compared with a pure copper busbar with a thickness of 2 mm;

[0047] Figure 6 , is for Example 3 of the present utility model. The copper plating layer or the surface copper material layer 202 with different thicknesses coated on the aluminum substrate layer 201 with a thickness of 4.8 mm is used to prepare a temperature rise trend diagram of a 300 μF capacitor product; a temperature rise comparison diagram compared with a pure copper busbar with a thickness of 3 mm;

[0048] Figure 7 , is for Comparative Example 1 of the present utility model. The copper plating layer or the surface copper material layer 202 with different thicknesses coated on the aluminum substrate layer 201 with a thickness of 3.21 mm is used to prepare a temperature rise trend diagram of a 200 μF capacitor product; a temperature rise comparison diagram compared with a pure copper busbar with a thickness of 2 mm;

[0049] Figure 8, which is Comparative Example 2 of the present utility model, is a schematic diagram of the temperature rise trend of a 400 μF capacitor product made of an aluminum substrate layer 201 with a thickness of 3.21 mm and a copper plating layer or a surface copper layer 202, and a schematic diagram of the temperature rise comparison compared with a pure copper busbar with a thickness of 2 mm;

[0050] In the figure, 1 is the busbar body, 101 is the external mounting terminal part, 102 is the busbar flat plate part, 103 is the busbar side baffle part, 104 is the core welding end part, 105 is the busbar flat plate cavity part, 201 is the aluminum substrate layer, and 202 is the surface copper layer.

[0051] Figures 4 - 8 In it, the X-axis represents the thickness of the copper layer in mm, and the thickness of the copper layer is also the thickness of the surface copper layer 202 coated or plated on the outer wall surface of the aluminum substrate layer 201; while the Y-axis represents the temperature rise in °C. Specific embodiments:

[0052] The following further details the present utility model in conjunction with the accompanying drawings and specific embodiments. The terms such as "upper", "lower", "bottom", "top", "left", "right", etc. in this application document are all in reference to the accompanying drawings disclosed in the present utility model. The busbar or capacitor busbar described in the present utility model has the same meaning. The thickness of aluminum and the thickness of the aluminum layer mentioned in the content of the present utility model both refer to the thickness of the aluminum substrate layer 201; while the thickness of copper refers to the thickness of the surface copper layer 202, and the copper busbar or pure copper busbar both refer to the copper busbar.

[0053] As Figures 1 - 3 shown, a novel low-cost capacitor busbar disclosed by the present utility model, the busbar includes a busbar body 1 and an external mounting terminal part 101. The busbar body 1 includes a busbar flat plate part 102 and a busbar side baffle part 103, that is, both the busbar flat plate part 102 and the busbar side baffle part 103 are made of a composite metal material, that is, both are structured with the surface copper layer 202 uniformly coated on the outer wall surface of the aluminum substrate layer 201 in a circumferential manner; the busbar side baffle part 103 is arranged at a corresponding position on one side of the busbar flat plate part 102, and one end of the external mounting terminal part 101 is connected to the corresponding position of the busbar side baffle part 103; a plurality of busbar flat plate cavity parts 105 are arranged on the surface of the busbar flat plate part 102, and a core welding end part 104 is arranged in each cavity of the busbar flat plate cavity part 105; one end of the core welding end part 104 is connected to the corresponding position of the busbar flat plate part 102, and the other end is used for externally connecting to the corresponding connection end such as a capacitor; the busbar flat plate part 102 and the busbar side baffle part 103 of the busbar body 1 are prepared from a composite metal material.

[0054] The composite metal material is composed of copper material and aluminum material; the aluminum material is the aluminum substrate layer 201 for preparing the busbar body 1, and the copper material is the surface copper layer 202, and the surface copper layer 202 is controlled to be evenly coated on the outer wall surface of the circumference of the aluminum substrate layer 201.

[0055] For the composite metal material forming the busbar body 1, the thickness ratio relationship between the aluminum substrate layer 201 and the surface copper layer 202 coated on the outer wall surface of the circumference of the aluminum substrate layer 201 is calculated according to the principle of the current skin effect of the metal material to ensure the overcurrent capacity of the busbar structure; the specific method and formula are as follows:

[0056] In the first step, calculate the resistance of the pure copper busbar, that is, the resistance of the pure copper busbar is calculated according to the following formula:

[0057]

[0058] r_copper_busbar -- the resistance of the copper busbar, that is, the resistance of the pure copper busbar,

[0059] ρ 铜 -- the resistivity of copper (Ω·m),

[0060] L -- the length of the busbar (m),

[0061] D -- the width of the busbar (m),

[0062] d 铜 -- the thickness of copper (m);

[0063] In the second step, according to the busbar for a composite metal material capacitor corresponding to the copper busbar to be prepared, that is, when the surface copper layer 202 is coated on the outer wall surface of the circumference of the aluminum substrate layer 201, the thickness of the aluminum substrate layer 201 is as follows. That is, when designing to adopt the thickness of the aluminum substrate layer 201, to ensure that the resistance of the aluminum substrate layer 201 thickness corresponds to the resistance of the pure copper busbar after coating the surface copper layer 202, the following calculation formula is satisfied:

[0064]

[0065] d 铝 -- the thickness of aluminum (m),

[0066] r 铜排 -- the resistance of the copper busbar (Ω),

[0067] ρ 铝 -- the resistivity of aluminum (Ω·m),

[0068] L -- the length of the busbar (m),

[0069] D -- the width of the busbar (m);

[0070] The third step is to substitute the calculation formula (1) into the calculation formula (2) for the aluminum layer thickness, that is, into the calculation formula (2) for the thickness of the aluminum substrate layer 201, to obtain the following calculation formula (3):

[0071]

[0072] d 铝 - Thickness of aluminum (m),

[0073] d 铜 - Thickness of copper (m),

[0074] ρ 铜 -- Resistivity of copper (Ω·m),

[0075] ρ 铝 -- Resistivity of aluminum (Ω·m).

[0076] Preferably, for a novel low-cost capacitor busbar, when the thickness of the busbar body made of pure copper material is 1 - 3 mm, the corresponding surface copper layer is uniformly coated on the outer wall surface of the aluminum substrate layer around the circumference to make a busbar body of the same specification, and the thickness of its surface copper layer: the thickness of the aluminum substrate layer = 0.1 - 0.14 mm: 1.6 - 4.8 mm.

[0077] For a novel low-cost capacitor busbar, when the thickness of the busbar body made of pure copper material is 1 mm, the corresponding surface copper layer is uniformly coated on the outer wall surface of the aluminum substrate layer around the circumference to make a busbar body of the same specification, and the thickness of its surface copper layer: the thickness of the aluminum substrate layer = 0.1 mm: 1.6 mm.

[0078] Preferably, when the thickness of the busbar body 1 made of pure copper material is 2 mm, the corresponding surface copper layer is uniformly coated on the outer wall surface of the aluminum substrate layer around the circumference to make a busbar body of the same specification, and the thickness of its surface copper layer: the thickness of the aluminum substrate layer = 0.1 mm: 3.21 mm.

[0079] For a novel low-cost capacitor busbar, when the thickness of the busbar body made of pure copper material is 3 mm, the corresponding surface copper layer is uniformly coated on the outer wall surface of the aluminum substrate layer around the circumference to make a busbar body of the same specification, and the thickness of its surface copper layer: the thickness of the aluminum substrate layer = 0.1 mm: 4.8 mm.

[0080] For the following specific embodiments, the parts not described are the same as those in this specific implementation manner and the description in the specification. That is, the capacitor busbar structures used in the following embodiments and comparative embodiments are the same as those described in the above specific implementation manner.

[0081] Example 1

[0082] A novel low-cost capacitor busbar disclosed in Embodiment 1 of the present utility model has an externally connected mounting terminal portion 101 made of pure copper structure. The so-called pure copper is red copper, such as Figure 1 shown, and all the materials required can be obtained commercially. The following embodiments are the same as the comparative embodiments.

[0083] Such as Figure 4 shown, which is a schematic diagram of the temperature rise trend of a 300 μF capacitor product prepared by plating or coating a surface copper layer 202 with different thicknesses on an aluminum substrate layer 201 with a thickness of 1.6 mm in Embodiment 1 of the present utility model, that is, curve 1-1; a schematic diagram of the comparison of the temperature rise compared with that of a pure copper busbar with a thickness of 1 mm, curve 1-2; the current passing frequency is 10 KHz, and the current is 100 A ripple current;

[0084] That is, a capacitor busbar prepared by coating a surface copper layer 202 with a thickness of 0.1 - 0.14 mm on an aluminum substrate layer 201 with a thickness of 1.6 mm is equivalent to a pure copper capacitor busbar with a thickness of 1 mm, and the same applies hereinafter.

[0085] Among them, curve 1-1 is an aluminum substrate layer 201 with a thickness of 1.6 mm as the base layer, and different thicknesses of surface copper layers 202 are vapor-deposited on the surface, with thicknesses of 0.02 mm, 0.04 mm, 0.08 mm, 0.1 mm, 0.12 mm, and 0.14 mm;

[0086] Curve 1-2 is a 300 μF capacitor with the same performance parameters made of a normal 1 mm thick pure copper bar. When the above current is applied, the temperature rise of the product is 14.7 °C;

[0087] Conclusion: It can be seen from the experimental data that under the same conditions, when the thickness of the copper layer reaches 0.1 mm and above, that is, the thickness of the surface copper layer 202, the over-current capacity effect of the novel low-cost capacitor busbar of the present utility model is basically the same as that of the pure copper bar.

[0088] In the following embodiments and comparative embodiments, except as described below, the rest not described are the same as those in Embodiment 1 above.

[0089] Embodiment 2

[0090] Such as Figure 5 shown, Figure 5 in, which is a schematic diagram of the temperature rise trend of a 300 μF capacitor product prepared by plating or coating a surface copper layer 202 on an aluminum substrate layer 201 with a thickness of 3.21 mm in Embodiment 2 of the present utility model, that is, curve 2-1; a schematic diagram of the comparison of the temperature rise compared with that of a pure copper busbar with a thickness of 2 mm, that is, curve 2-2; the passing frequency is 10 KHz, and the current is 100 A ripple current;

[0091] Among them, curve 2-1 is an aluminum layer with a base layer thickness of 3.21 mm, and copper layers with different thicknesses are vapor-deposited on the surface, with thicknesses of 0.02 mm, 0.04 mm, 0.08 mm, 0.1 mm, 0.12 mm, and 0.14 mm;

[0092] Curve 2-2 is a capacitor with the same performance parameters of 300 μF made of a pure copper busbar with a normal thickness of 2 mm. When the above-mentioned current is applied, the temperature rise of the product is 13.1 °C;

[0093] Conclusion: It can be seen from the experimental data that under the same conditions, when the copper layer thickness reaches 0.1 mm or more, the over-current capacity effect of the new busbar structure of the present invention is basically the same as that of the pure copper busbar.

[0094] Embodiment 3

[0095] As Figure 6 shown, this is an embodiment of the present invention, a schematic diagram of the temperature rise trend of a 300 μF capacitor product made of an aluminum substrate layer 201 with a thickness of 4.8 mm plated or coated with a surface copper layer 202, that is, curve 3-1; a schematic diagram of the temperature rise comparison with a pure copper busbar with a thickness of 3 mm, that is, curve 3-2; through a frequency of 10 KHz and a current of 100 A ripple current; among them, curve 3-1 is an aluminum layer with a base layer thickness of 4.8 mm, and copper layers with different thicknesses are vapor-deposited on the surface, with thicknesses of 0.02 mm, 0.04 mm, 0.08 mm, 0.1 mm, 0.12 mm, and 0.14 mm;

[0096] Curve 3-2 is a capacitor with the same performance parameters of 300 μF made of a pure copper busbar with a normal thickness of 2 mm. When the above-mentioned current is applied, that is, through a frequency of 10 KHz and a current of 100 A ripple current; the temperature rise of the product is 12.6 °C;

[0097] Conclusion: It can be seen from the experimental data that under the same conditions, when the copper layer thickness reaches 0.1 mm or more, the over-current capacity effect of the new low-cost capacitor busbar is basically the same as that of the pure copper busbar or pure copper busbar of this specification.

[0098] Comparative Example 1

[0099] This Comparative Example 1 is compared with Embodiment 2. As Figure 7 shown, this is Comparative Example 1 of the present invention, a schematic diagram of the temperature rise trend of a 200 μF capacitor product made of an aluminum substrate layer 201 with a thickness of 3.21 mm plated or coated with a surface copper layer 202, that is, curve 4-1; a schematic diagram of the temperature rise comparison with a pure copper busbar with a thickness of 2 mm, that is, curve 4-2; through a frequency of 10 KHz and a current of 100 A ripple current;

[0100] Among them, curve 4-1 shows that the base layer is an aluminum layer with a thickness of 3.21 mm, and copper layers with different thicknesses are vapor-deposited on the surface, with thicknesses of 0.02 mm, 0.04 mm, 0.08 mm, 0.1 mm, 0.12 mm, and 0.14 mm;

[0101] Curve 4-2 is a capacitor with the same performance parameters of 300 μF made of a normal pure copper bar with a thickness of 2 mm. When the above-mentioned current is applied, the temperature rise of the product is 19.1 °C;

[0102] Conclusion: It can be seen from the experimental data that under the same conditions, when the copper layer thickness reaches 0.1 mm or more, the overcurrent capacity effect of the new busbar structure is basically the same as that of the pure copper bar. That is, when using the busbar for low-cost capacitors of the present invention with the same structure to make capacitors of different specifications and capacities, the performance generated is the same. In this comparative example, the temperature rise trend of the 200 μF capacitor product is the same as that of the 300 μF capacitor in Example 1.

[0103] Comparative Example 2

[0104] As Figure 8 shown, this is the temperature rise trend schematic diagram of the 400 μF capacitor product made by plating or coating the surface copper layer 202 on the 3.21 mm thick aluminum substrate layer 201 in Comparative Example 2 of the present invention, that is, curve 5-1; the temperature rise comparison schematic diagram compared with the pure copper busbar with a thickness of 2 mm, that is, curve 5-2; through a frequency of 1 0 KHz and a current of 100 A ripple current;

[0105] Among them, curve 5-1 shows that the base layer is an aluminum layer with a thickness of 3.21 mm, and copper layers with different thicknesses are vapor-deposited on the surface, with thicknesses of 0.02 mm, 0.04 mm, 0.08 mm, 0.1 mm, 0.12 mm, and 0.14 mm;

[0106] Curve 5-2 is a capacitor with the same performance parameters of 300 μF made of a normal pure copper bar with a thickness of 2 mm. When the above-mentioned current is applied, the temperature rise of the product is 9.7 °C;

[0107] Conclusion: It can be seen from the experimental data that under the same conditions, when the copper layer thickness reaches 0.1 mm or more, the overcurrent capacity effect of the new busbar structure is basically the same as that of the pure copper bar.

[0108] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes can be made to these embodiments without departing from the principles and spirit of the present invention, and all fall within the scope of this patent protection.

Claims

1. A novel low-cost busbar for capacitors, the busbar comprising a busbar body and an external mounting terminal portion, the busbar body comprising a busbar plane plate portion and a busbar side baffle portion, the busbar side baffle portion being arranged at a corresponding position on one side of the busbar plane plate portion, one end of the external mounting terminal portion being connected to a corresponding position of the busbar side baffle portion; a plurality of busbar flat plate cavities are arranged on the surface of the busbar plane plate portion, and a core welding end portion is arranged in the inner cavity of each busbar plane plate cavity portion; the characteristics are: The busbar plane plate portion and the busbar side baffle portion of the busbar body are made of composite metal materials.

2. A novel low-cost busbar for capacitors according to claim 1, characterized in that The composite metal material is composed of copper and aluminum; the aluminum is controlled to be an aluminum substrate layer for preparing the busbar body, and the copper is a surface copper layer, and the surface copper layer is controlled to be evenly coated on the outer wall surface of the aluminum substrate layer.

3. A novel low-cost busbar for capacitors according to claim 1, characterized in that The thickness of the busbar body made of pure copper material is 1-3mm, and the corresponding surface copper layer is evenly coated on the outer wall surface of the aluminum substrate layer to form a busbar body of corresponding specifications. The surface copper layer thickness: aluminum substrate layer thickness = 0.1-0.14mm: 1.6-4.8mm.

4. A novel low-cost busbar for capacitors according to claim 3, characterized in that When the thickness of the busbar body made of pure copper material is 1mm, the corresponding surface copper layer is evenly coated on the outer wall surface of the aluminum substrate layer to form a busbar body of the same specification, and the thickness of the surface copper layer: the thickness of the aluminum substrate layer = 0.1mm: 1.6mm.

5. A novel low-cost busbar for capacitors according to claim 3, characterized in that When the thickness of the busbar body made of pure copper material is 2mm, the corresponding surface copper layer is evenly coated on the outer wall surface of the aluminum substrate layer to form a busbar body of the same specification, and the thickness of the surface copper layer: the thickness of the aluminum substrate layer = 0.1mm: 3.21mm.

6. A novel low-cost busbar for capacitors according to claim 3, characterized in that When the thickness of the busbar body made of pure copper material is 3mm, the corresponding surface copper layer is evenly coated on the outer wall surface of the aluminum substrate layer to form a busbar body of the same specification, and the surface copper layer thickness: aluminum substrate layer thickness = 0.1mm: 4.8mm.

7. A novel low-cost busbar for capacitors according to claim 1 or 2, characterized in that The external mounting terminal part and the core welding end part are made of pure copper material; the external mounting terminal part is set as an inverted U-shaped structure, and one side of the inverted U-shaped structure is connected to the corresponding position of the busbar side baffle part.

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