High-temperature-resistant and high-ripple-current-resistant DC-link thin-film capacitor for new energy field

Abstract

The utility model provides a DC-link film capacitor with high temperature resistance and high ripple current in the new energy field and a method, the DC-link film capacitor comprises a flame-retardant plastic shell, an insulating epoxy resin adhesive layer, a capacitor roll core and a metal connecting layer arranged at the corresponding position of the winding side wall surface of the capacitor roll core, and two tinned outgoing lines are connected to the corresponding positions of the two side wall surfaces of the metal connecting layer. By effectively improving the heat conductivity coefficient and the heat dissipation capability of the capacitor, heat in the inner core of the capacitor can be quickly and effectively dissipated, heat balance in a capacitor product is achieved, the capacitor has high temperature resistance, the charging time can be greatly shortened, and the service life of the capacitor is prolonged. The high-temperature-resistant high-ripple-current capacity requirement of capacitors in the new energy field such as the new energy field is met, the preparation process is simple, and the cost is low.

Description

Technical Field

[0001] The utility model relates to the technical field of capacitor product production, in particular to a high-temperature resistant and high-ripple current capacitor specially used in the new energy field, such as a charging column, that is, a high-temperature resistant and high-ripple current DC-link film capacitor used in the new energy field. Background Art

[0002] With the continuous development and progress of industrial science and technology, the product quality requirements for capacitors used in the industrial field and new energy vehicles such as charging columns are higher. Film capacitors have high reliability, excellent frequency characteristics, and low dielectric loss. They have rapidly developed from the original home appliance field to the new energy field and other fields. The DC-link film capacitor is widely used. The capacitor is connected in parallel on the DC side after the rectifier bridge to play a filtering and voltage stabilization role. Since the capacity required by the DC-Link capacitor is relatively high, people have mostly used electrolytic capacitors for a long time, because electrolytic capacitors have the advantages of large single capacitance and small size, but relative to the advantages of electrolytic capacitors, its disadvantages are also obvious, that is, low withstand voltage, not resistant to high temperature, unstable performance and short life. The properties of the alumina dielectric used in electrolytic capacitors and the conductivity of the electrolyte limit its maximum withstand voltage value and high temperature resistance, so DC-Link capacitors are widely used.

[0003] At the same time, due to the high ripple frequency and large ripple current of DC-LINK film capacitors, the internal resistance requirements of film capacitors are very high, the heat dissipation capacity of the product needs to be good, and the temperature resistance of DC-link is getting higher and higher. At present, ordinary DC-LINK on the market can no longer meet its requirements, and customers are pursuing smaller and smaller volumes. Therefore, without increasing the volume, DC-LINK capacitors with high temperature resistance and high ripple current resistance have strong market competitiveness. Ordinary DC-LINK film capacitors usually use metal film structures, and their temperature resistance is generally up to about 85℃, and their ripple current capacity is about 0.4A per meter. The existing new energy fields, such as the capacitor products used in the new energy field, have high requirements for temperature and ripple current, generally around 100℃ or above. At the same time, due to the space restrictions of the demand for the new energy field, the volume of its capacitor cannot change significantly, that is, it is not only required to meet the conditions of high temperature resistance and high ripple current, but also cannot increase its volume, which can greatly shorten the charging time in the new energy field. The volume of DC-LINK film capacitors remains unchanged or even requires smaller requirements.

[0004] For example, Chinese patent announcement number CN 103151169 A) utility model name "A film capacitor for DC-link occasions", this utility model relates to the technical field of power electronic capacitors, and in particular to a DC support and DC-link capacitor used in AC / inverter equipment, specifically a film capacitor for DC-link occasions, which has the advantages of small capacity and filtering area, low cost, reliable and stable, high safety performance, etc., and can replace electrolytic capacitors on a large scale in DC-link occasions in the field of power electronics. It includes a capacitor core, characterized in that the capacitor core is wound by a metallized polypropylene film, the metallized polypropylene film includes a polypropylene film medium and a capacitor plate, and the capacitor plate is a metal coating evaporated on the polypropylene film medium.

[0005] It can be seen from the above disclosed prior art solutions that none of the above technical solutions discloses that the DC-link film capacitor can increase its high temperature resistance and improve its high ripple current, while the volume of the capacitor will not increase, so as to effectively solve the demand for DC-LINK film capacitors with high temperature resistance and high ripple current capability in the 800V silicon carbide new energy field, while not increasing the volume, etc.

[0006] Therefore, how to provide a DC-link film capacitor and method for use in the new energy field that is resistant to high temperature and high ripple current, which can effectively improve its thermal conductivity and improve the heat dissipation capacity of the capacitor, so that the heat in the capacitor core can be quickly and effectively dissipated, achieve thermal balance in the capacitor product, and significantly shorten the charging time, meet the requirements of high temperature and high ripple current capacity of capacitors in the new energy field, thereby ensuring the reliability of the product and providing a fast charging experience for the new energy field. The prepared DC-link film capacitor has good quality stability and consistency, while reducing the production cost of the capacitor and improving the heat resistance and high ripple capacity of the DC-link film capacitor. Utility Model Content

[0007] The utility model discloses a high-temperature resistant and high-ripple current DC-link film capacitor for use in the field of new energy, comprising a flame-retardant plastic shell 1, an insulating epoxy resin adhesive layer 2, a capacitor core 3, and a metal connection layer 301 arranged at corresponding positions on the winding side wall surface of the capacitor core 3, two tinned lead wires 8 are connected to corresponding positions on the two side walls of the metal connection layer 301, and the heat in the capacitor core can be quickly and effectively dissipated by effectively improving its thermal conductivity and improving the heat dissipation capacity of the capacitor, so as to achieve thermal balance in the capacitor product, have high temperature resistance, and can greatly shorten the charging time, meet the requirements of high temperature resistance and high ripple current capacity of capacitors in the field of new energy, such as the field of new energy, and have a simple preparation process and low cost.

[0008] The utility model provides a high-temperature resistant and high-ripple current DC-link film capacitor for use in the field of new energy, comprising a flame-retardant plastic shell, an insulating epoxy resin adhesive layer, a capacitor core, and a metal connection layer and a tinned lead wire arranged at corresponding positions on the winding side wall surface of the capacitor core. The flame-retardant plastic shell is set as a groove inner cavity structure with an open end at one end and a closed end at the other end. The capacitor core is set in the groove inner cavity formed by the flame-retardant plastic shell. One end of the tinned lead wire is fixedly electrically connected to the metal connecting layer on the winding side wall surface of the capacitor core. The capacitor core is located at the corresponding position of the connecting layer and is fixedly packaged at the open end of the inner cavity of the flame-retardant plastic shell, and the other end extends out of the open end of the flame-retardant plastic shell; the capacitor core located at the open end of the flame-retardant plastic shell and the two tinned lead wires fixedly connected to the capacitor core are fixedly packaged through an insulating epoxy resin layer, and the outer wall surface of the capacitor core circumference between the closed end of the flame-retardant plastic shell and the fixed package junction of the insulating epoxy resin layer and the corresponding side surface of the flame-retardant plastic shell are fixedly packaged and connected as a whole through an insulating silicone layer.

[0009] The DC-link film capacitor with high temperature resistance and high ripple current used in the new energy field, wherein the capacitor winding core includes a metal film sheet, and the metal film sheet is composited by a film layer and a metal layer, and the metal layer includes an aluminum-plated layer and a zinc-plated layer, the aluminum-plated layer is composited on one side wall of the film layer, and the zinc-plated layer is composited on the other side wall of the aluminum-plated layer corresponding to the contact with the film layer.

[0010] The high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field is characterized in that the volume ratio of the insulating epoxy resin layer encapsulated in the open end of the inner cavity of the groove of the flame-retardant plastic shell and the insulating silicone layer located in the inner cavity of the groove of the flame-retardant plastic shell and located between the outer wall surface of the capacitor winding core circumference and the wall surface of one side corresponding to the flame-retardant plastic shell is controlled to be 30-40:70-60.

[0011] The high temperature resistant and high ripple current DC-link film capacitor for new energy field is divided into a thickened area, a transition area and a common area in the horizontal axial direction of the flattened metal film sheet; the thickened area and the transition area are sequentially set as a thin film layer, an aluminum-plated layer and a galvanized layer in the radial direction of the metal film sheet, the galvanized layer is in a trapezoidal structure and is composited on the corresponding position of one side wall of the aluminum-plated layer, the long side of the trapezoidal structure of the galvanized layer along the horizontal axial direction is in contact with the aluminum-plated layer, the hypotenuse of the trapezoidal structure of the galvanized layer intersects from high to low along the axial direction at the corresponding position on the wall of the aluminum-plated layer surface in contact with the galvanized layer, and the horizontal plane length of the hypotenuse of the trapezoidal structure galvanized layer is controlled to correspond to the length of the transition zone; and the common area includes the thin film layer and the aluminum-plated layer.

[0012] The high temperature resistant and high ripple current DC-link thin film capacitor for use in the new energy field, wherein the capacitor winding core is formed by staggered and superimposed winding of the thickened area ends and the common area ends of two metal film sheets; and the thickened area end of one metal film sheet and the common area end of another metal film sheet are controlled to be staggered and superimposed respectively before winding; and the length of the overlapping composite connection interval of the common area is controlled to be 10.5-11.8% of the sum of the lengths of the thickened area, the transition area and the common area when the two metal film sheets are wound.

[0013] The high temperature resistant and high ripple current DC-link film capacitor used in the new energy field controls the length of the thickened area along the horizontal axial direction to be 10.5-11.8% of the sum of the lengths of the thickened area, the transition area and the common area along the axial horizontal direction.

[0014] The DC-link film capacitor prepared by the utility model with high temperature resistance and high ripple current for new energy field and the method has the characteristics of high temperature resistance and high ripple current, and is suitable for use in new energy field, such as new energy field, and the prepared film capacitor has a small volume, that is, it will not increase the size of its preparation. At the same time, the DC-link film capacitor prepared by the utility model has the following characteristics after actual testing and use:

[0015] First, the capacitors in the prior art usually reduce the equivalent series resistance (ESR) by increasing the volume, but the volume that customers are pursuing is getting smaller and smaller. This solution can no longer meet customer requirements. Therefore, without increasing the volume, the high-temperature resistant and high-ripple current DC-LINK film capacitor prepared by the utility model can greatly meet market demand. This is because the overlapping length of the ordinary area on the metal film sheet 9 of the capacitor winding core 3 is increased, and the length of the thickened area, i.e., the galvanized layer, is increased. For example, the thickened area of ​​the prior art is about 2.5 mm, while the length of the thickened area of ​​the utility model is at least 3 mm, which is an increase of more than 20%, thereby greatly reducing the internal resistance of the prepared DC-LINK film capacitor, and the corresponding ripple current capacity can be increased by about 20%; thereby greatly increasing the current flow capacity of the DC-LINK film capacitor;

[0016] Second, the existing common DC-LINK film capacitors use a metal film structure. According to practical tests, its ripple current capacity is about 0.4A per meter. The potting material used is the insulating epoxy resin layer 2 shown in the figure. The thermal conductivity of the insulating epoxy resin layer is about 0.18-0.25w / m·k. Its heat dissipation capacity is low. When the inner core of the product capacitor reaches 105°C, it is difficult to dissipate the heat. When thermal equilibrium cannot be achieved, the inner core temperature of the battery product will rise sharply, causing the DC-LINK film capacitor to fail. It cannot meet the requirements of new energy fields such as charging piles for capacitors with small size and large overcurrent, that is, high temperature resistance and high ripple current. The structure adopted by the utility model is as follows Figure 1 , 2 3, the metal film structure shown in the figure reduces the equivalent series resistance (ESR) by increasing the length of the thickened area and the transition area, that is, the length along the horizontal axial direction, that is, the galvanized layer 5 in the thickened area is set as a trapezoidal structure, thereby reducing the internal resistance of the DC-LINK film capacitor, so that the equivalent series resistance (ESR) can be reduced by about 40%, and the specific data is shown in Table 1. Under the same load condition, its temperature rise can be reduced by about 60%, and the specific data is shown in Table 2. At the same time, the potting material uses a silicone potting material whose thermal conductivity is 15 times that of the insulating epoxy resin layer 2 of the prior art. In this way, the internal resistance of the DC-LINK film capacitor core can be effectively reduced and the internal heat can be dissipated. The inner core can also easily transfer its heat at 120°C, so that it can reach thermal balance faster, thereby ensuring the reliability of the product. That is, the high temperature and high ripple current capability of the DC-LINK film capacitor is greatly improved; the electrical parameter performance of the product is improved.

[0017] The performance of the DC-link film capacitor core prepared by using the high temperature resistant and high ripple current DC-link film capacitor for the new energy field disclosed by the utility model: its 100KHz frequency internal resistance change and its 100KHz, 900Vdc, 10Arms temperature rise comparison test description at an ambient temperature of 70°C: that is, a comparison description of the performance of the DC-link film capacitor product prepared with the prior art.

[0018] Product description: the experimental samples are from the same batch of experimental products, and the rest of the production materials and process conditions used are exactly the same;

[0019] Table 1 shows the DC-link film capacitors prepared by the method of the utility model and the DC-link film capacitors prepared by the prior art. At 1200V 3μF, the internal resistance changes at 100KHz frequency are as follows (mΩ);

[0020] Table 1, (Batch No.: R211129023-2)

[0021]

[0022] In Table 1, the DC-link film capacitor with a common structure, i.e., prepared by the prior art method, takes 1200V 3μF as an example, and its internal resistance changes at a frequency of 100KHz. The DC-link film capacitor prepared by the method of the utility model in the embodiment of the present invention takes 1200V 3μF as an example, and its internal resistance changes at a frequency of 100KHz. The internal resistance of the DC-link film capacitor prepared by the utility model is nearly 40% lower than that of the prior art solution, reaching 36.7%. The technical effect of excessive ripple electric waves is achieved. The above Table 1 discloses the internal resistance data comparison of five DC-link film capacitors prepared by the structure of the method of the utility model. The preparation method and structure are as described in Example 1.

[0023] Table 2 shows the temperature rise comparison of 100KHz, 900Vdc, 10Arms at an ambient temperature of 70℃ (℃), that is, the temperature change when the capacitor is overcurrent;

[0024]

[0025] In Table 1, the DC-link film capacitor prepared by the conventional structure, i.e., the prior art method, is Comparative Example 1. Taking 1200V 3μF as an example, the temperature rise comparison (℃) changes at 100KHz, 900Vdc, and 10Arms at an ambient temperature of 70℃, while the DC-link film capacitor prepared by the method of the utility model in the embodiment of the present invention takes 1200V 3μF as an example. At an ambient temperature of 70℃, the temperature rise comparison (℃) changes at 100KHz, 900Vdc, and 10Arms. It shows that the temperature rise of the DC-link film capacitor of the present utility model is more than 40% lower than that of the prior art. Disclosed in the above table is the comparison of the temperature rise data of five DC-link film capacitors prepared by the structure of the method of the utility model. The preparation method and structure are as described in Example 1. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 , is a schematic diagram of the cross-sectional structure of a DC-LINK thin film capacitor prepared by a utility model method according to an embodiment,

[0027] Figure 2 , is a schematic diagram of the longitudinal cross-sectional structure of a DC-LINK thin film capacitor prepared by the utility model method in one embodiment;

[0028] Figure 3 , is a schematic diagram of the structure of two metal film sheets used for winding a capacitor core according to an embodiment of the utility model;

[0029] In the figure, 1. flame retardant plastic shell, 101. open end, 102. closed end, 103. groove inner cavity, 2. insulating epoxy resin glue layer, 3. capacitor core, 301. metal connection layer, 4. insulating silicone layer, 5. galvanized layer, 6. aluminum-plated layer, 7. polypropylene film layer or film layer, 8. tinned lead wire, 9. metal film sheet A, 901. metal film sheet B.

[0030] 9. Metal film sheet A and 901. Metal film sheet B are both metal film sheets of the present invention, and both have the same material and structure.

[0031] L1 is the length distance of the thickened area of ​​the metal film sheet A9 and the ordinary area of ​​the metal film sheet B 901 of the present invention overlapping and contacting along the axial direction after the ordinary areas of the two metal film sheets overlap and correspond to each other;

[0032] L2 is the length of the thickened area of ​​the metal layer on the metal film sheet of the utility model along the horizontal axial direction, that is, the short side length of the galvanized layer 5 on the metal film sheet A9 and the metal film sheet B901 in the horizontal axial direction of the trapezoidal structure, that is, the length distance of the thickened area on the film sheet A9 and the metal film sheet B901 along the horizontal axial direction; DETAILED DESCRIPTION

[0033] The utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The words such as upper, lower, bottom, top, left, and right mentioned in this application document are all for the drawings disclosed in the specification of the utility model. The epoxy resin adhesive layer and the insulating epoxy resin adhesive layer mentioned in the utility model have the same meaning, and the film layer or the polypropylene film layer have the same meaning.

[0034] like Figure 1-3As shown, the utility model discloses a high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field, comprising a flame retardant plastic shell 1, an insulating epoxy resin adhesive layer 2, a capacitor core 3, and a metal connection layer 301 arranged on a corresponding position of the winding side wall surface of the capacitor core 3, two tinned lead wires 8 are connected to corresponding positions of the wall surfaces on both sides of the metal connection layer 301, the flame retardant plastic shell 1 is set as a groove cavity 103 structure with an open end 101 at one end and a closed end 102 at the other end, the capacitor core 3 is arranged in the groove cavity 103 formed by wrapping the flame retardant plastic shell 1, and one end of the tinned lead wire 8 is fixedly electrically connected to the electrical The capacitor core 3 is wound around the corresponding position of the metal connecting layer 301 on the side wall, and is fixedly encapsulated in the open end 101 of the inner cavity of the flame-retardant plastic shell 1, and the other end extends out of the open end 101 of the flame-retardant plastic shell 1; the capacitor core 3 located at the open end 101 of the flame-retardant plastic shell 1 and the two tinned lead wires 8 fixedly connected to the capacitor core 3 are fixedly encapsulated by the insulating epoxy resin layer 2, and the outer wall surface of the capacitor core 3 located between the closed end 102 of the flame-retardant plastic shell 1 and the fixed encapsulation joint of the insulating epoxy resin layer 2 is fixedly connected to the corresponding side surface of the flame-retardant plastic shell 1 through the insulating silicone layer 4 as a whole.

[0035] The capacitor winding core 3 includes a metal film sheet, which is composed of a film layer 7 and a metal layer. The metal layer includes an aluminum-plated layer 6 and a zinc-plated layer 5. The aluminum-plated layer 6 is compounded on one side wall of the film layer 7, and the zinc-plated layer 5 is compounded on the other side wall of the aluminum-plated layer 6 corresponding to the contact with the film layer 6.

[0036] The volume ratio of the insulating epoxy resin layer 2 encapsulated in the open end 101 of the groove inner cavity of the flame-retardant plastic shell 1 and the insulating silicone layer 4 located between the outer wall of the capacitor winding core 3 and the side wall corresponding to the flame-retardant plastic shell 1 in the groove inner cavity 103 of the flame-retardant plastic shell 1 is controlled to be 30-40:70-60.

[0037] The metal film sheet is divided into a thickened area, a transition area and a common area in the horizontal axial direction of the flat spread; the thickened area and the transition area are arranged along the radial direction of the metal film sheet, that is, from the adjacent Figure 3 From bottom to top in the vertical direction, a film layer 7, an aluminum-plated layer 6 and a galvanized layer 5 are sequentially arranged. The galvanized layer 5 is in a trapezoidal structure and is compounded on a corresponding position of a wall surface of one side of the aluminum-plated layer 6. The horizontal side of the trapezoidal structure of the galvanized layer 5 along the axial direction is in contact with the aluminum-plated layer 6, that is, the long side of the trapezoidal structure of the galvanized layer 5. The hypotenuse of the trapezoidal structure of the galvanized layer 5 intersects from high to low along the axial direction at the corresponding position on the wall surface of the aluminum-plated layer 6 on the side in contact with the galvanized layer 5, and the length of the hypotenuse of the trapezoidal structure galvanized layer 5 along the horizontal plane direction is controlled to correspond to the length of the transition zone. The ordinary zone includes the film layer 7 and the aluminum-plated layer 6.

[0038] The capacitor winding core 3 is formed by winding two metal film sheets with the ends of the thickened area and the ends of the ordinary area offset and superimposed; and the thickened area end of one metal film sheet and the ordinary area end of the other metal film sheet are controlled to be offset and superimposed respectively before winding; when the two metal film sheets are wound, the length of the overlapping composite connection interval of the ordinary area is controlled to be 10.5-11.8% of the sum of the lengths of the thickened area, the transition area and the ordinary area.

[0039] The length of the thickened zone along the axial horizontal direction is controlled to be 10.5-11.8% of the sum of the lengths of the thickened zone, the transition zone and the ordinary zone along the axial horizontal direction.

[0040] The preparation method of the high temperature resistant and high ripple current DC-link film capacitor for the new energy field described in the utility model includes the preparation of the capacitor winding core 3, and the specific method steps are as follows: 1) the thickened area end of one metal film sheet and the ordinary area end of another metal film sheet are staggered and overlapped, and the length of the overlapping part of the ordinary areas of the two metal film sheets is controlled to account for 10.5-11.8% of the total length of the thickened area, transition area and ordinary area of ​​the metal layer on the surface of the film layer 7; at the same time, the thickness of the metal film sheet is kept at 10.5-11.8%. The length of the thickened area is equal to or slightly less than the length of the thickened area; at the same time, the length of the thickened area arranged at the end of the thickened area of ​​the metal film sheet 9 is controlled to be 10.5-11.8% of the sum of the lengths of the thickened area, the transition area and the ordinary area of ​​the metal layer arranged on the surface of the thin film layer 7; the two metal film sheets overlapped according to the above specifications are wound into a capacitor winding core shape, a metal connecting layer 301 is arranged on the two side parts of the wound capacitor winding core, and two tinned lead wires 8 are fixedly connected at the corresponding positions of the metal connecting layer 301 to form a capacitor winding core 3;

[0041] 2) Add insulating silicone into the groove inner cavity 103 formed by the flame-retardant plastic shell 1 and the other end corresponding to the open end 101 and the closed end 102, and insert the capacitor core 3 body with tinned lead wires 8 fixedly connected to the two side walls into the groove inner cavity 103 formed by the flame-retardant plastic shell 1 and provided with insulating silicone, and fill the outer wall of the capacitor core 3 and the wall of one side corresponding to the flame-retardant plastic shell 1 in the groove inner cavity 103 with insulating silicone, and form an insulating silicone layer 4 after drying and curing; then use the insulating epoxy resin layer 2 at the open end 101 to encapsulate the capacitor core 3 with two tinned lead wires 8 in the groove inner cavity 103 formed by the flame-retardant plastic shell 1, so as to prepare a DC-link film capacitor with high temperature resistance and high ripple current.

[0042] The galvanized layer 5 disposed on the aluminum-plated layer 6 is controlled to have a trapezoidal structure to form a thickened area and a transition area; the length of the transition area is the length of the oblique line from the top edge of the thickened area to the connecting contact with the surface of the aluminum-plated layer 5.

[0043] Any matters not described in the following specific embodiments are the same as the description in this specific implementation mode and the specification. Example

[0044] The utility model discloses a high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field and a preparation method thereof, such as Figure 1-3 As shown, in this embodiment, the length of the two metal film sheets A 9 and the metal film sheet B 901 used to prepare the capacitor core 3 along the horizontal plane direction or along the axial direction is 26 mm, that is, the sum of the lengths of the thickened area, the transition area and the ordinary area on the metal film sheet A 9 along the axial direction is 26 mm; similarly, the sum of the lengths of the thickened area, the transition area and the ordinary area on the metal film sheet B 901 along the axial direction is also 26 mm; the thickened area of ​​the metal film sheet A 9 and the ordinary area of ​​the metal film sheet B 901 are staggered and superimposed to wind the capacitor core for explanation, as shown in FIG. Figure 3 shown.

[0045] like Figure 1-3 As shown, the utility model discloses a high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field, comprising a flame retardant plastic shell 1, an insulating epoxy resin adhesive layer 2, a capacitor core 3, and a metal connection layer 301 arranged on a corresponding position of the winding side wall surface of the capacitor core 3, two tinned lead wires 8 are connected to corresponding positions of the wall surfaces on both sides of the metal connection layer 301, the flame retardant plastic shell 1 is set as a groove cavity 103 structure with an open end 101 at one end and a closed end 102 at the other end, the capacitor core 3 is arranged in the groove cavity 103 formed by wrapping the flame retardant plastic shell 1, and one end of the tinned lead wire 8 is fixedly electrically connected to the electrical The capacitor core 3 is wound around the corresponding position of the metal connecting layer 301 on the side wall, and is fixedly encapsulated in the open end 101 of the inner cavity of the flame-retardant plastic shell 1, and the other end extends out of the open end 101 of the flame-retardant plastic shell 1; the capacitor core 3 located at the open end 101 of the flame-retardant plastic shell 1 and the two tinned lead wires 8 fixedly connected to the capacitor core 3 are fixedly encapsulated by the insulating epoxy resin layer 2, and the outer wall surface of the capacitor core 3 located between the closed end 102 of the flame-retardant plastic shell 1 and the fixed encapsulation joint of the insulating epoxy resin layer 2 is fixedly connected to the corresponding side surface of the flame-retardant plastic shell 1 through the insulating silicone layer 4 as a whole.

[0046] The capacitor core 3 is formed by winding two metal film sheets, namely, a thickened area of ​​a metal film sheet A9 and a common area of ​​another metal film sheet B901, which are staggered and corresponding to each other; the metal film sheet A9 and the metal film sheet B901 are both composited with a thin film layer 7 and a metal layer, and the metal layer includes an aluminum-plated layer 6 and a galvanized layer 5, the aluminum-plated layer 6 is composited on one side wall of the thin film layer 7, and the galvanized layer 5 is composited on the other side wall of the aluminum-plated layer 6 corresponding to the contact with the thin film layer 6. The metal film sheet is divided into a thickening zone, a transition zone and a common zone in sequence along the horizontal axial direction of the flattened metal film sheet; the thickening zone and the transition zone are set as a thin film layer 7, an aluminum-plated layer 6 and a galvanized layer 5 in sequence along the radial direction of the metal film sheet, the galvanized layer 5 is in a trapezoidal structure and is composited to the corresponding position of the other side wall surface of the aluminum-plated layer 6 in contact with the thin film layer 7, the galvanized layer 5 is set as a trapezoidal structure with the horizontal side along the horizontal axial direction, that is, the long side of the trapezoidal structure is in contact with the aluminum-plated layer 6, the hypotenuse of the trapezoidal structure of the galvanized layer 5 intersects from high to low along the axial direction at the corresponding position on the wall surface of the aluminum-plated layer 6 on the side in contact with the galvanized layer 5, the length of the hypotenuse of the trapezoidal structure of the galvanized layer 5 is equal to the length of the transition zone; that is, the horizontal plane length of the hypotenuse of the trapezoidal structure galvanized layer 5 corresponds to the length of the transition zone; and the common zone includes the thin film layer 7 and the aluminum-plated layer 6. That is, the length of the common area on the metal film sheet is equal to the length of the aluminum layer 6 combined on the film layer 7; that is, the length of the aluminum layer 6 combined on the film layer 7 is equal to the length of the film layer 7, the aluminum layer 6 is combined on the film layer 7, the zinc layer 5 is combined on the surface of the aluminum layer 6, the longest side of the trapezoidal zinc layer 5 is compositely connected to the corresponding position on the surface of the aluminum layer 6, and the length of the shortest side in the axial direction, i.e., the thickened area, and the length of the trapezoidal hypotenuse, i.e., the transition zone, in the horizontal direction are equal to or equal to the longest side of the zinc layer 5;

[0047] The capacitor winding core 3 is formed by staggering and superimposing the end of the thickened area of ​​the metal film sheet A9 and the end of the ordinary area of ​​the metal film sheet B901; and the end of the thickened area of ​​the metal film sheet A9 and the ordinary area end of another metal film sheet B901 are controlled to be staggered and superimposed respectively before winding; when the two metal film sheets are wound, the length of the overlapping composite connection interval of the ordinary area is controlled to be 10.5-11.8% of the sum of the lengths of the thickened area, transition area and ordinary area. In this embodiment, the lengths of L1 and L2 are both 3mm. That is, the horizontal axial length of the trapezoidal structure of the thickened area of ​​the metal film sheet A9 is the short side length L2 of the thickened area, and L2 is controlled to be 3mm;

[0048] The volume ratio of the insulating epoxy resin layer 2 encapsulated in the open end 101 of the groove inner cavity of the flame-retardant plastic shell 1 and the insulating silicone layer 4 located between the outer wall surface of the circumference of the capacitor winding core 3 and the side wall surface corresponding to the flame-retardant plastic shell 1 in the groove inner cavity 103 of the flame-retardant plastic shell 1 is controlled to be 30:70; and the thermal conductivity of the insulating silicone layer 4 is controlled to be greater than the thermal conductivity of the insulating epoxy resin layer.

[0049] The specific preparation method is the preparation of the capacitor winding core 3. The metal film sheet A9 and the metal film sheet B901 involved in the following have the same material and structure. In order to clearly illustrate the present invention, the metal film sheets are numbered for illustration, and the following comparative examples are also the same. The specific method steps are as follows: 1) The thickened area end of the metal film sheet A9 and the ordinary area end of another metal film sheet B901 are staggered and overlapped, and the length of the overlapping part of the ordinary area of ​​the metal film sheet A9 and the metal film sheet B901 is controlled to account for 10.5-11.8% of the total length of the thickened area, transition area and ordinary area of ​​the metal layer on the surface of the thin film layer 7, and L1 is actually controlled to be 3mm; at the same time, the length L2 and L1 of the thickened area on the metal film sheet A9 are kept equal to 3mm; the metal film sheet A9 and the metal film sheet B901 overlapped according to the above specifications are overlapped. 901 is wound into a capacitor core shape, a metal connection layer 301 is provided on two side surfaces of the wound capacitor core, and two tinned lead wires 8 are fixedly connected at corresponding positions of the metal connection layer 301 to form a capacitor core 3 body;

[0050] 2) Insert the capacitor core 3 body with tinned lead wires 8 fixedly connected to the two side walls into the groove inner cavity 103 formed by the flame-retardant plastic shell 1 and provided with the insulating silicone. The outer wall of the capacitor core 3 and the wall of the flame-retardant plastic shell 1 corresponding to one side of the groove inner cavity 103 are filled with insulating silicone. At the same time, the upper open end of the capacitor core 3 with two tinned lead wires 8 is encapsulated in the groove inner cavity 103 formed by the flame-retardant plastic shell 1 using the insulating epoxy resin layer 2 at the open end 101. Then, after drying and curing, the insulating silicone forms an insulating Silicone layer 4; the volume ratio of the insulating epoxy resin layer 2 and the insulating silicone layer 4 is controlled to be 30:70; that is, the insulating silicone layer 4 located in the groove cavity 103 of the flame-retardant plastic shell 1 from the bottom of the outer wall of the capacitor core 3 to the contact with the insulating epoxy resin layer 2 accounts for 70% of the volume ratio, and the insulating epoxy resin layer 2 of the upper end surface of the capacitor core 3 and the surrounding related parts encapsulated in the upper open end 101 of the flame-retardant plastic shell 1 accounts for 30% of the volume ratio; that is, the insulating epoxy resin layer 2 used to encapsulate the upper end surface of the capacitor core 3 and the surrounding related parts and the insulating silicone layer 4 located in the groove cavity 103 of the flame-retardant plastic shell 1 from the bottom of the outer wall of the capacitor core 3 to the contact with the insulating epoxy resin layer 2 The volume ratio is 30%:70%;

[0051] Since the thermal conductivity of the insulating silicone layer 4 is higher, its heat dissipation effect is higher than that of the insulating epoxy resin layer 2, which greatly improves the heat dissipation speed of the prepared DC-link film capacitor and enables it to reach thermal equilibrium faster. A DC-link film capacitor with high temperature resistance and high ripple current is made. The performance of the C-link film capacitor prepared by the method of the utility model is shown in Tables 1 and 2 above. The internal resistance of the DC-link film capacitor of the utility model is smaller than that of the prior art, and the heat dissipation is faster.

[0052] Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope is defined by the appended claims and their equivalents, and all fall within the scope of this patent protection law.

Claims

1. A high temperature resistant and high ripple current DC-link film capacitor for use in the field of new energy, comprising a flame retardant plastic shell, an insulating epoxy resin adhesive layer, a capacitor core, and a metal connection layer and a tinned lead wire arranged at a corresponding position on the winding side wall of the capacitor core. The flame retardant plastic shell is set as a groove inner cavity structure with an open end at one end and a closed end at the other end. The capacitor core is arranged in the groove inner cavity formed by the flame retardant plastic shell. One end of the tinned lead wire is fixedly electrically connected to the corresponding position of the metal connection layer on the winding side wall of the capacitor core, and is fixedly encapsulated in the open end of the inner cavity of the flame retardant plastic shell, and the other end extends out of the open end of the flame retardant plastic shell; its characteristics are: The capacitor core located at the open end of the flame-retardant plastic shell and two tinned lead wires fixedly connected to the capacitor core are fixedly packaged by an insulating epoxy resin layer, and the outer wall surface of the capacitor core circumference between the closed end of the flame-retardant plastic shell and the junction of the insulating epoxy resin layer fixed packaging and the corresponding side surface of the flame-retardant plastic shell are fixedly packaged and connected as a whole by an insulating silicone layer.

2. A high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field according to claim 1, characterized in that The capacitor winding core includes a metal film sheet, which is composed of a film layer and a metal layer. The metal layer includes an aluminum-plated layer and a zinc-plated layer. The aluminum-plated layer is compounded on one side wall of the film layer, and the zinc-plated layer is compounded on the other side wall of the aluminum-plated layer corresponding to the contact with the film layer.

3. The high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field according to claim 1 is characterized in that The volume ratio of the insulating epoxy resin layer encapsulated in the open end of the inner cavity of the flame-retardant plastic shell groove and the insulating silicone layer located between the outer wall of the capacitor winding core and the side wall corresponding to the flame-retardant plastic shell in the inner cavity of the groove of the flame-retardant plastic shell is controlled to be 30-40:70-60.

4. The high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field according to claim 2 is characterized in that The metal film sheet is divided into a thickening zone, a transition zone and a common zone in sequence along the horizontal axial direction of the flattened metal film sheet; the thickening zone and the transition zone are set as a thin film layer, an aluminum-plated layer and a galvanized layer in sequence along the radial direction of the metal film sheet, the galvanized layer is in a trapezoidal structure and is composited to a corresponding position on one side wall of the aluminum-plated layer, the long side of the trapezoidal structure of the galvanized layer along the horizontal axial direction is in contact with the aluminum-plated layer, the hypotenuse of the trapezoidal structure of the galvanized layer intersects from high to low along the axial direction at a corresponding position on the wall of the aluminum-plated layer surface in contact with the galvanized layer, and the horizontal plane length of the hypotenuse of the trapezoidal structure galvanized layer is controlled to correspond to the length of the transition zone; and the common zone includes a thin film layer and an aluminum-plated layer.

5. The high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field according to claim 2 is characterized in that The capacitor winding core is formed by winding two metal film sheets with the ends of the thickened areas and the ends of the ordinary areas offset and stacked; and the thickened area end of one metal film sheet and the ordinary area end of the other metal film sheet are controlled to be offset and stacked respectively before winding; when the two metal film sheets are wound, the length of the overlapping composite connection interval of the ordinary area is controlled to be 10.5-11.8% of the sum of the lengths of the thickened area, the transition area and the ordinary area.

6. A high temperature resistant and high ripple current DC-link film capacitor for use in the new energy field according to claim 4 or 5, characterized in that The length of the thickened zone along the horizontal axial direction is controlled to be 10.5-11.8% of the sum of the lengths of the thickened zone, the transition zone and the ordinary zone along the axial horizontal direction.

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