A type of surface mount capacitor

Abstract

This invention provides a surface mount capacitor, comprising: a package having two opposing end faces and a side surface distributed circumferentially between the two end faces; a chip disposed within the package, the end face of the chip being parallel to the corresponding end face of the package; and leads, including external leads, a connecting portion, and a multi-protrusion soldering portion; the multi-protrusion soldering portion and the connecting portion are disposed within the package, the connecting portion connecting the multi-protrusion soldering portion and the external leads; two leads are provided, each lead having its corresponding multi-protrusion soldering portion spirally and symmetrically connected to the corresponding soldering surface of the chip; the two external leads are respectively disposed on opposite sides of the package along the circumferential direction. By structurally improving existing surface mount capacitors, this invention meets further application requirements and extreme parameter requirements, satisfying the actual needs of enterprises.

Description

Technical Field

[0001] This invention relates to the field of capacitor technology, and in particular to a surface mount capacitor. Background Technology

[0002] Surface mount capacitors refer to ceramic dielectric capacitors. Currently, ceramic dielectric capacitors account for about 70% of the capacitor market, becoming an indispensable component in electronic devices. They mainly include multilayer ceramic capacitors and single-layer ceramic capacitors.

[0003] Traditional multilayer ceramic capacitors suffer from problems such as a large number of electrodes, numerous interlayer current loops, high inductance, and poor high-frequency characteristics. Single-layer ceramic capacitors have better high-frequency characteristics, but low, medium, and high voltage single-layer ceramic capacitors are basically packaged in a plug-in manner, which results in a large size and inconvenience for assembly.

[0004] Meanwhile, traditional surface mount capacitors have insufficient high voltage and high current resistance, which cannot meet the needs of further application scenarios, such as engineering equipment, new energy vehicles, and large electrical equipment.

[0005] Therefore, it is necessary to provide a surface mount capacitor to solve the above-mentioned technical problems. Summary of the Invention

[0006] To address the problems of the prior art, one embodiment of this specification provides a surface mount capacitor, comprising: a package having two opposing end faces and a side face distributed circumferentially between the two end faces; a chip disposed within the package, the end face of the chip being parallel to the corresponding end face of the package; and leads including external leads, connecting portions, and multi-protrusion solder portions; the multi-protrusion solder portions and the connecting portions are disposed within the package, the connecting portions connecting the multi-protrusion solder portions and the external leads; two leads are provided, and the corresponding multi-protrusion solder portions of each lead are respectively connected to the two opposite ends of the chip; the two external leads are respectively disposed on the outside of opposite sides of the package along the circumferential direction.

[0007] In some embodiments, the external pin includes a support plate and a first bent portion and a second bent portion disposed on opposite sides of the support plate; the first bent portion is bent along a direction close to the package portion and is connected to the connecting portion; the second bent portion is bent along a direction away from the package portion.

[0008] In some embodiments, the first bent portion and the support plate are provided with a first groove, the first groove dividing the first bent portion into two first connecting feet.

[0009] In some embodiments, each connecting part has an integrally formed first connecting end and second connecting end; the two legs of the first connecting end are respectively connected to the corresponding first connecting legs.

[0010] In some embodiments, the multi-protrusion weld portion has a plurality of protrusions distributed circumferentially, one of which is connected to the second connection end.

[0011] In some embodiments, at least a portion of the second connection end is parallel to the corresponding welding surface, and the minimum distance between the second connection end and the chip is determined according to a preset electrical breakdown parameter; the first connection end is arc-shaped, and the curvature of the first connection end is set based on the minimum distance between the second connection end and the chip.

[0012] In some embodiments, the second bend is provided with a second groove for dividing the second bend into two second connecting feet. The welding surface is provided with a plurality of stepped surfaces, the number of which is determined based on a first preset electrical strength of the chip. Along the direction from the center to the edge of the welding surface, the distance between the plurality of stepped surfaces and the connecting portion decreases sequentially.

[0013] In some embodiments, the plurality of stepped surfaces include at least a first stepped surface and a second stepped surface; the second stepped surface is distributed in a ring around the circumference of the first stepped surface; the welded portion is connected to the first stepped surface; the second stepped surface is provided with a long creepage reinforcement portion, the long creepage reinforcement portion including at least one annular protrusion.

[0014] In some embodiments, the outer side of the annular protrusion is connected to the step surface by a first rounded corner, and the inner side of the annular protrusion is connected to the step surface or adjacent step surfaces by a second rounded corner. Both the first rounded corner and the second rounded corner include two tangentially connected arcs, and the radius of the arcs is determined based on the number of step surfaces. The arcs include a first arc and a second arc, and the diameter of the second arc is larger than the diameter of the first arc.

[0015] In some embodiments, the number of annular protrusions is determined based on the chip's preset physical strength requirements and preset electrical parameters. Attached Figure Description

[0016] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0017] Figure 1 This is a schematic diagram of the surface mount capacitor structure shown in some embodiments of this specification;

[0018] Figure 2 This is a cross-sectional view of a surface-mount capacitor shown in some embodiments of this specification;

[0019] Figure 3 This is a schematic diagram of the chip and pin structure shown in some embodiments of this specification;

[0020] Figure 4 This is a schematic diagram of the chip structure shown in some embodiments of this specification.

[0021] Explanation of reference numerals in the attached drawings: 100, package portion; 110, first inclined surface; 120, second inclined surface; 200, chip; 210, first step; 220, second step; 230, annular protrusion; 300, pin; 310, external pin; 311, first bend; 3111, first groove; 312, second bend; 3121, second groove; 313, support plate; 320, connecting portion; 321, first connecting end; 322, second connecting end; 330, multi-protrusion welding portion; 331, protrusion. Detailed Implementation

[0022] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0023] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0024] Existing single-layer ceramic capacitors often employ a plug-in package structure, which suffers from large size and inconvenient assembly. Some embodiments in this specification provide a surface-mount capacitor that can be injection molded, eliminating the assembly step, reducing the overall size of the surface-mount capacitor, and facilitating rapid molding to improve production efficiency and capacitor quality. Further details regarding surface-mount capacitors can be found in the related descriptions below.

[0025] Figure 1 This is a schematic diagram of the structure of a surface-mount capacitor according to some embodiments of this specification. Figure 2This is a cross-sectional view of a surface-mount capacitor shown according to some embodiments of this specification.

[0026] like Figure 1 , Figure 2 As shown, the surface mount capacitor includes a package 100, a chip 200, and pins 300.

[0027] The encapsulation portion 100 is used to encapsulate at least a portion of the chip 200 and the pins 300, thereby providing a seal and protection for the chip 200 and the pins 300. In some embodiments, the encapsulation portion 100 can be injection molded, for example, by mounting the chip 200 and the pins 300 in a mold, forming an injection space inside the mold, with at least a portion of the chip 200 and the pins 300 located within the injection space, injecting hot-melt injection molding material into the injection space, and allowing the encapsulation portion 100 to solidify after the injection molding material cools. The injection molding material can include various types, such as resin, plastic, etc.

[0028] In some embodiments, the encapsulation portion 100 has two opposing end faces and a circumferentially distributed side surface between the two end faces. In some embodiments, the encapsulation portion 100 can be designed in various shapes, such as cylindrical, prismatic, or other shapes, and its specific shape can be set according to actual needs.

[0029] Chip 200 is used to store a preset program. In some embodiments, chip 200 is disposed within package 100. In some embodiments, chip 200 has two opposing solder surfaces for soldering to at least a portion of pins 300, and the solder surfaces of chip 200 may be parallel to the corresponding end face of package 100.

[0030] Pin 300 is used for connection to other structures, such as soldering to a circuit board.

[0031] In some embodiments, pin 300 may include a multi-protrusion solder portion 330, a connection portion 320, and an external pin 310.

[0032] The multi-protrusion solder joint 330 is used for electrical connection with the chip 200. In some embodiments, the multi-protrusion solder joint 330 may be electrically connected to the chip 200 by soldering.

[0033] A multi-protrusion solder joint 330 and a connecting joint 320 are disposed within the package portion 100, with the connecting joint 320 connecting between the multi-protrusion solder joint 330 and the external pin 310. In some embodiments, the external pin 310 on the pin 300 is connected to other structures.

[0034] In some embodiments, the multi-protrusion welding portion 330, the connecting portion 320, and the external pin 310 can be integrally formed. The pin 300 can be formed by bending a sheet material. In some embodiments, the pin 300 can be made of a variety of materials, such as at least one of copper, nickel, gold, and silver. In some embodiments, the pin 300 can be bent into various shapes, and its specific shape can be set according to actual needs.

[0035] In some embodiments, two pins 300 are provided, one as a positive pin and the other as a negative pin. The multi-protrusion solder portions 330 corresponding to the two pins 300 are respectively connected to opposite ends of the chip 200. External pins 310 corresponding to the two pins 300 are respectively provided on the outer sides of opposite sides of the package portion 100 along the circumferential direction. The external pins 310 corresponding to the two pins 300 can be symmetrically distributed on both sides of the package portion 100. The connecting portions 320 and multi-protrusion solder portions 330 corresponding to the two pins 300 can be symmetrically or rotationally symmetrically distributed at opposite ends of the chip 200.

[0036] In some embodiments of this specification, the surface-mount capacitors, with their corresponding connection portions 320 and multi-protrusion solder portions 330 connected to the chip 200 via a spiral symmetrical design rather than a simple symmetrical design, effectively increase the electrical distance between the pins 300 and the edge of the chip 200. This improves the overall high-voltage and current withstand characteristics of the surface-mount capacitor, meeting the practical needs of scenarios requiring higher electrical parameters. Furthermore, compared to the traditional 90° bending structure, the spiral shape offers greater toughness, making it better suited for applications in high-vibration environments such as new energy vehicles and engineering vehicles, thus enhancing reliability.

[0037] The surface mount capacitors shown in some embodiments of this specification are injection molded, which can reduce the size of the surface mount capacitor itself and eliminate the assembly process, thereby improving the efficiency and accuracy of processing and molding.

[0038] Pin 300 is soldered to the circuit board, providing support for package 100 and allowing current to pass through. During use, chip 200 and pin 300 will generate heat, causing the overall temperature of the capacitor to rise. Therefore, heat dissipation treatment is required for the surface mount capacitor.

[0039] Figure 3 This is a schematic diagram of the chip and pin structure shown in some embodiments of this specification.

[0040] In some embodiments, such as Figure 2 , Figure 3 As shown, the external pin 310 includes a support plate 313 and a first bent portion 311 and a second bent portion 312 disposed on opposite sides of the support plate 313.

[0041] The first bending portion 311 and the second bending portion 312 are respectively structures formed by bending relative to the support plate 313.

[0042] In some embodiments, the first bending portion 311 bends along a direction close to the encapsulation portion 100, and the first bending portion 311 is connected to the connecting portion 320. At least a portion of the first bending portion 311 can extend into the interior of the encapsulation portion 100, thereby forming a certain gap between the support plate 313 and the encapsulation portion 100. The size of the gap is a preset value, such as 1mm, 2mm, or other values, and the specific value can be set according to actual needs. By reserving this gap, the external pin 310 has a certain deformation space, which allows the external pin 310 to adaptively undergo elastic deformation when connected to the circuit board, thereby improving the adaptability to special application scenarios and also improving heat dissipation performance.

[0043] In some embodiments, the angle between the first bending portion 311 and the support plate 313 is a preset value, such as 90°, 95° or other values, and the specific value can be set according to actual needs.

[0044] In some embodiments, the second bend 312 is bent in a direction away from the package portion 100. The second bend 312 can be connected to a circuit board, and the second bend 312 can be arranged parallel to the circuit board, thereby increasing the contact area between the external pin 310 and the circuit board. The sides of the second bends 312 corresponding to the two pins 300 facing the circuit board can be located in the same plane, thereby facilitating the simultaneous connection of the second bends 312 corresponding to the two pins 300 to the circuit board.

[0045] In some embodiments, the corners of the external pins 310 can be rounded to avoid sharp corners or protrusions on the external pins 310, thus preventing stress concentration.

[0046] In some embodiments, such as Figure 3 As shown, the first bending part 311 and the support plate 313 are provided with a first groove 3111, which is used to separate the first bending part 311 to form two first connecting feet.

[0047] At least a portion of each of the two first connecting pins can extend into the encapsulation portion 100 and connect with the connecting portion 320. By providing the first groove 3111, a hollow channel can be formed on the first bending portion 311 and the support plate 313. At the same time, the two symmetrically arranged pins 300 can form a non-sealed, non-obstructing injection channel. On the one hand, this allows the injection molding material to flow more smoothly through the first groove 3111, avoiding obstruction of the flow of the injection molding material by the first bending portion 311 and the support plate 313. On the other hand, it ensures that the internal air is fully squeezed out during the injection process, making it easier for the injection molding material to fill the entire injection space. This is beneficial for improving the flowability of the injection molding material during filling and improving the efficiency and quality of injection molding.

[0048] During the injection molding process, the first groove 3111 can enhance the venting of the injection gap, prevent gas from being unable to escape and forming bubbles in the packaging part 100, thereby improving the overall compactness of the packaging part 100, strengthening the insulation performance between the chip 200 and the packaging part 100, greatly reducing the injection molding difficulty of the packaging part 100, and improving the packaging effect and reliability of the packaging part 100.

[0049] The first groove 3111 also enables the first bending part 311 and the support plate 313 to form a bifurcated structure, increasing the elasticity and bendability of the first bending part 311 and the support plate 313. In applications such as automotive and engineering equipment, this makes the external pin 310 have higher vibration resistance and allows the external pin 310 to have a certain degree of deformation, which greatly improves the overall reliability and service life of the chip capacitor.

[0050] In some embodiments, the corners of the first groove 3111 can be rounded. For example, the first groove 3111 may include an arc-shaped groove and a straight-line groove. The arc-shaped groove may be located at one end of the support plate 313 facing the first bend 311, and the straight-line groove communicates with the opening of the arc-shaped groove, dividing the first bend 311 into a forked structure. This avoids the formation of sharp corners within the first groove 3111, thereby preventing stress concentration, resulting in a more uniform current distribution and ensuring product performance.

[0051] The larger the width ratio of the first groove 3111, the smoother the injection material filling during injection molding, and the higher the injection efficiency and air bubble removal efficiency. However, the hardness of the outer pin 310 will decrease accordingly. To ensure the quality of the outer pin 310, i.e., to prevent deformation, the width ratio of the first groove 3111 can be as large as possible. In this embodiment, the width of the first groove 3111 is determined based on preset first mechanical strength, injection molding process parameters (e.g., injection pressure, injection speed, etc.), and first electrical characteristic requirements (e.g., current carrying capacity, high-frequency / radio frequency parameters, etc.). As a preferred embodiment, the ratio of the width of the first groove 3111 to the width of the outer pin 310 along the width direction is a preset value, for example, between 2:5 and 4:5. The specific value can also be set according to actual needs. The length direction of the outer pin 310 is perpendicular to the direction from the first bend 311 to the second bend 312, and the width direction of the outer pin 310 is perpendicular to its length direction. By setting the first groove 3111 according to the above proportions, the external pin 310 can achieve the best balance in terms of injection molding convenience, injection molding sufficiency, mechanical strength and electrical characteristics.

[0052] In some embodiments, such as Figure 3 As shown, each connecting part 320 has an integrally formed first connecting end 321 and second connecting end 322.

[0053] The two pins of the first connection terminal 321 are respectively used to connect to the corresponding first connection pin 311 to ensure the uniformity of current.

[0054] In some embodiments, the connecting portion 320 is provided with a groove to divide the end of the connecting portion 320 facing the first connecting foot 311 into two first connecting ends 321. The groove communicates with the first groove 3111 and forms a through hole, which can further increase the space for the injection molding material to flow, further improve the smoothness of the injection molding material flow and the efficiency of air bubble discharge, thereby further improving the quality of injection molding and the overall quality of the encapsulation portion 100.

[0055] In some embodiments, the width of the groove on the connecting portion 320 may be the same as the width of the first groove 3111. The groove on the connecting portion 320 may be an arc-shaped groove to avoid the formation of sharp corners and stress concentration, and to facilitate uniform current distribution.

[0056] In some embodiments, such as Figure 3As shown, the multi-protrusion weld portion 330 has a plurality of protrusions 331 distributed circumferentially, one of which is connected to the second connecting end 322. In some embodiments, the plurality of protrusions 331 are rotationally symmetrically and uniformly distributed along the circumference of the multi-protrusion weld portion 330. In some embodiments, the number of protrusions 331 is a preset value, for example, 2, 3, 4 or other numbers, and the specific number can be set according to actual needs. The number of protrusions 331 is negatively correlated with the size of the protrusions 331, and the number of protrusions 331 is negatively correlated with the deformation resistance of the protrusions 331. The number of protrusions 331 can be determined based on the size of the protrusions 331 and the required strength. As an example only, three protrusions 331 can be used to ensure that the protrusions 331 are not easily deformed. The three protrusions 331 can be rotationally symmetrically and uniformly distributed at 120° intervals.

[0057] In some embodiments, the protrusion 331 may include a variety of shapes, such as a circle, rectangle, arc, strip, triangle, polygon, or any combination thereof, and its specific shape may be set according to actual needs.

[0058] By setting the protrusions 331, the contact area between the multi-protrusion welding part 330 and the chip 200 can be increased, thereby improving the welding strength between the multi-protrusion welding part 330 and the chip 200. While ensuring the welding strength, a certain gap can be reserved between adjacent protrusions 331, thereby saving materials.

[0059] In some embodiments, the multi-protrusion solder portion 330 and the protrusion 331 can be soldered to one end of the chip 200 using solder paste.

[0060] Sharp structures on electrically conductive circuits are prone to parasitic signal radiation and tip discharge, which can cause unnecessary electromagnetic interference. Circular arcs can suppress tip radiation and improve the electromagnetic compatibility of high-frequency circuits.

[0061] In some embodiments, to avoid parasitic signal radiation, tip discharge, and other phenomena caused by the formation of sharp corners in the multi-protrusion welded portion 330, a rounded transition can be adopted at the corners between the multi-protrusion welded portion 330 and the protrusion 331.

[0062] That is, the edges of each protrusion 331, as well as the connection between the protrusion 331 and the multi-protrusion welded part 330, can be designed as arcs or rounded corners, so that the edges of the multi-protrusion welded part 330 and the protrusion 331 can be smoothly transitioned, avoiding stress concentration. At the same time, it avoids the formation of sharp corners that would cause electric field and current density concentration, thus preventing the product performance from being affected by the concentration of electric field and current density.

[0063] The smooth transition of rounded corners or arcs allows for more even current distribution, which helps to extend the overall lifespan of surface mount capacitors. Furthermore, the rounded contours facilitate smoother solder flow and improve solder wetting, ensuring adequate tinning at the branch positions formed by the 331 protrusion, reducing soldering defects such as short circuits and insufficient solder, and enhancing the long-term reliability of surface mount capacitors.

[0064] In some embodiments, such as Figure 2 , Figure 3 As shown, at least a portion of the second connecting end 322 is parallel to the corresponding welding surface, and at least a portion of the end of the second connecting end 322 facing the connecting portion 330 is bent toward the connecting portion 330 to facilitate the connection between the second connecting end 322 and the connecting portion 330.

[0065] In some embodiments, the minimum distance between the second connection terminal 322 and the chip 200 is determined according to a preset electrical breakdown parameter.

[0066] Electrical breakdown parameters are used to describe the relevant parameters of the material between the second connection terminal 322 and the chip 200 being electrically broken down. Electrical breakdown parameters may include breakdown voltage and electrical strength.

[0067] Preset electrical breakdown parameters are used to describe preset electrical breakdown parameters, such as the maximum voltage of the pre-designed chip capacitor during use and the electrical strength of the injection molding material used.

[0068] In some embodiments, the minimum distance between the second connection terminal 322 and the chip 200 may be positively correlated with the breakdown voltage and negatively correlated with the electrical strength. In some embodiments, the operator may calculate the minimum distance between the second connection terminal 322 and the chip 200 based on a first preset algorithm. For example, the first preset algorithm may include formula (1):

[0069]

[0070] Where d is the minimum distance between the second connection terminal 322 and the chip 200, P is the correction coefficient, U is the maximum voltage of the pre-designed surface-mount capacitor during use, and E is the electrical strength of the injection molding material. Here, E represents the inherent characteristics of the injection molding material, which can be determined by consulting existing information, and U is the design parameter.

[0071] In practical applications, due to various factors such as voltage fluctuations and material uniformity, the ratio of U to E can only be determined as an approximation of the electrical breakdown distance. During calculation, a correction factor can be added to make the calculated distance greater than the actual breakdown distance, thus ensuring safety. P is a preset value, which can be any value between 0.05 and 0.2 mm. Its specific value can also be determined by other methods, such as obtaining it from historical data, setting it based on experience, or setting it according to actual needs.

[0072] In some embodiments, such as Figure 2 , Figure 3 As shown, the first connecting end 321 can be arc-shaped, and the curvature of the first connecting end 321 is determined based on the distance between the second connecting end 322 and the welding surface.

[0073] In some embodiments, the first connection end 321 is curved in an arc shape towards the side of the chip 200 away from the chip 200. In some embodiments, the curvature of the connection portion 320 can be set according to actual needs.

[0074] In some embodiments, the operator may calculate the curvature of the first connection end 321 based on a second preset algorithm. For example, the second preset algorithm may include formula (2):

[0075]

[0076] Where C represents the curvature of the first connection terminal 321, R is the base radius, and d is the minimum distance between the second connection terminal 322 and the chip 200. The base radius is a preset value and can be determined based on the thickness of the chip 200. For example, the base radius can be greater than or equal to half the thickness of the chip 200, or less than or equal to the thickness of the chip 200. Its specific value can be selected according to actual needs. The curvature of the first connection terminal 321 is determined based on the minimum distance between the second connection terminal 322 and the chip 200. Under the condition that the second connection terminal 322 meets the preset electrical breakdown parameters, the distance between the first connection terminal 321 and the chip 200 can be increased, thereby enhancing the overall electrical performance of the surface mount capacitor and improving the overall reliability of the surface mount capacitor. At the same time, sufficient space is formed between the first connection terminal 321 and the chip 200 to accommodate an appropriate amount of injection molding material to ensure the electrical isolation performance between the first connection terminal 321 and the chip 200, avoiding waste due to excessive material and unnecessary increase in the size of the surface mount capacitor.

[0077] In some embodiments, the central angle corresponding to the connecting portion 320 can be designed to be various, such as 120°, 135°, 150° or other angles.

[0078] The connecting portion 320 is designed as an arc, so that the groove on the first connecting end 321 and the first groove 3111 on the first bending portion 311 are set at an angle and are not located in the same plane, thereby forming channels in different directions. During the injection molding and encapsulation process of the part 100, the obstruction of the connecting portion 320 to the flow of injection molding material in different directions can be reduced, which is conducive to increasing the flow of injection molding material, and also conducive to completely filling the mold with injection molding material to improve molding accuracy, and completely expelling the internal air to the outside.

[0079] Designing the connector 320 as an arc shape can further increase the gap between the connector 320 and the chip 200, thereby meeting the higher electrical isolation requirements between the connector 320 and the chip 200, avoiding unnecessary contact between the connector 320 and the chip 200, and allowing current to flow from the multi-protrusion soldering part 330 to the connector 320, ensuring the electrical performance of the chip capacitor.

[0080] At the same time, bending the connector 320 into an arc shape can increase the elasticity of the connector 320 and improve the overall vibration resistance of the chip capacitor.

[0081] In some embodiments, the thickness of the pins 300 is consistent throughout, that is, the thickness of the external pins 310, the connection portion 320, and the multi-protrusion solder portion 330 is consistent throughout. This ensures that when current flows through the pins 300, the current distribution is uniform, which helps to improve the overall lifespan of the surface mount capacitor.

[0082] In existing designs, the second bending part 312 is often designed as a bending piece for bonding and soldering to an external circuit board. However, in actual applications, technicians have found that when this design is applied to special scenarios (such as new energy vehicles, engineering vehicles, etc.), the severe vibration can cause the bending piece to desolder or break from the circuit board, which greatly reduces its service life and performance.

[0083] To address the aforementioned technical problems, in some embodiments, such as Figure 3 As shown, the second bent portion 312 is provided with a second groove 3121.

[0084] The second groove 3121 is used to divide the second bend 312 into two second connecting feet. In some embodiments, the second groove 3121 may be located at the middle of the second bend 312, and the opening of the second groove 3121 faces the side of the second bend 312 away from the support plate 313.

[0085] By setting the second groove 3121, the second bent portion 312 can be divided into a forked structure. When the second bent portion 312 is soldered to the circuit board, the second bent portion 312 has a certain space for thermal expansion deformation, which prevents the second bent portion 312 from warping when heated, so that the second bent portion 312 can be completely attached to the circuit board, thereby improving the soldering stability.

[0086] Meanwhile, by setting the second groove 3121, the overall welding surface area of ​​the second bend 312 can be reduced, further optimizing the basic electrical performance of the chip capacitor, such as the loss tangent. By setting the second groove 3121, the fluidity of the solder paste can be enhanced during the reflow soldering flux evaporation and wetting process, and air impurities inside the solder paste can be squeezed out, reducing the proportion of voids generated during the welding of the second bend 312, thereby improving the welding quality. In specific applications (such as new energy vehicles, engineering vehicles, etc.), the above design can also effectively mitigate the impact of severe vibration on the pin 300, ensuring a reliable connection between the second bend 312 and the circuit board, and improving service life.

[0087] In actual implementation, the design of the second groove 3121 has a significant impact on the actual performance of the chip capacitor. If the groove diameter is too large, it will greatly reduce the mechanical strength of the second bending part 312, making it prone to deformation and breakage. If the groove diameter is too small, its shock resistance will be limited and it will not meet the actual needs.

[0088] In some embodiments, the second groove 3121 can be any one of an arc-shaped groove, a triangular groove, a trapezoidal groove, etc., and the corners of the second groove 3121 can be rounded. The diameter of the second groove 3121 is determined according to the preset second mechanical strength requirements, second electrical characteristic requirements, and welding process parameters. The larger the size of the second groove 3121, the stronger the thermal deformation capability of the second bending portion 312. The size of the second groove 3121 can be designed according to actual needs.

[0089] As a preferred embodiment, the second groove 3121 can be designed as a semi-circular groove. The ratio of the diameter of the second groove 3121 to the width of the second bend 312 can be between 8:10 and 9:10. Relevant experimental analysis has confirmed that this ratio achieves an optimal balance of mechanical, weldability, and electrical performance. The width of the second bend 312 refers to the vertical distance from the side of the second bend 312 away from the support plate 313 to the support plate 313. Using this dimension for the second groove 3121 effectively improves weld strength and reliability, enhances heat dissipation, reduces mechanical stress, and prevents pad failure.

[0090] After the second bending part 312 is connected to the circuit board, a certain gap can be reserved between the encapsulation part 300 and the circuit board to avoid direct contact between the encapsulation part 300 and the circuit board. When the encapsulation part 300 heats up, it helps to dissipate heat and avoid heat accumulation at the connection between the encapsulation part 300 and the circuit board.

[0091] Figure 4 This is a schematic diagram of the chip structure shown in some embodiments of this specification.

[0092] In some embodiments, such as Figure 3 , Figure 4 As shown, chip 200 is disk-shaped, with multiple stepped surfaces on its soldering surface. The number of stepped surfaces is determined based on the chip's preset electrical strength. Along the direction from the center to the edge of the soldering surface, the distance between the multiple stepped surfaces and the connecting portion 320 decreases sequentially. By setting the stepped surfaces, the thickness of chip 200 increases sequentially from the center to the edge with different stepped surfaces. Along the direction from the center to the edge of chip 200, the electric field strength within chip 200 can be gradually reduced, avoiding a high electric field strength at the edge of chip 200, which could easily lead to arcing on both sides of the chip 200 electrodes when the voltage of chip 200 is high.

[0093] Electrical strength refers to the maximum electric field strength that a material can withstand when electrically broken down. The first preset electrical strength may include the maximum electric field strength that the chip 200 can withstand when electrically broken down. The first preset electrical strength is a preset value and can be designed according to actual needs. In some embodiments, the operator can calculate the number of step surfaces based on a third preset algorithm. The third preset algorithm may include formula (3):

[0094]

[0095] Where S is the number of stepped surfaces after rounding, D is the maximum thickness of the chip 200 during design, and U is the maximum voltage during design. For the electrical strength of chip 200, As the first coefficient, This is the second coefficient. The first coefficient is used to correct the breakdown thickness of chip 200. By adding a certain thickness to the breakdown thickness of chip 200, the minimum thickness of chip 200 is determined, ensuring that the minimum thickness of chip 200 is greater than the breakdown thickness, thereby improving the safety of chip 200. The second coefficient is used to correct the determined number of step surfaces, which can improve the accuracy of determining the number of step surfaces. D, U, and The preset value can be obtained in various ways, such as from historical data, by looking up a table, or by using at least one of the following methods: experience-based preset.

[0096] The plurality of stepped surfaces includes at least a first stepped surface 210 and a second stepped surface 220. The second stepped surface 220 is distributed in a ring around the first stepped surface 210. The multi-protruding welded portion 330 is connected to the first stepped surface 210.

[0097] In some embodiments, the chip 200 can be designed as a disk, the first step surface 210 can be designed as a circle, and the second step surface 220 can be designed as an annular shape. The chip 200, the first step surface 210 and the second step surface 220 can be arranged coaxially.

[0098] In some embodiments, the diameter of the first step surface 210 can be larger than the maximum width of the multi-protrusion solder portion 330, allowing the first step surface 210 to completely cover the multi-protrusion solder portion 330 and preventing the solder portion 330 from contacting the second step surface 220. The centroid of the solder portion 330 can be aligned with the centroid of the first step surface 210, thereby preventing the solder portion 330 from shifting onto the second step surface 220 when soldering to the chip 200, thus avoiding voids during soldering and improving the overall electrical performance of the surface mount capacitor. Simultaneously, the first step surface 210 and the multi-protrusion solder portion 330 allow for sufficient margin at the edges of the multi-protrusion solder portion 330, preventing contact between the multi-protrusion solder portion 330 and the second step surface 220 due to soldering process deviations, which could result in incomplete soldering.

[0099] By setting the first step surface 210 and the second step surface 220, the end face of the chip 200 can form a stepped surface, allowing the electrical strength of the chip 200 to gradually decrease from the center to the periphery in a stepped manner. This improves the overall voltage withstand strength of the chip 200 and helps extend its service life. Here, electrical strength refers to the ratio between breakdown voltage and thickness. Simultaneously, the stepped structure at both opposite ends of the chip 200 effectively increases the electrical clearance distance between the two ends, enhancing the overall reliability of the chip 200.

[0100] In some embodiments, such as Figure 4 As shown, a long creepage reinforcement portion is provided on the second step surface 220, and the long creepage reinforcement portion includes at least one annular protrusion 230. In a first preferred embodiment, the long creepage reinforcement portion is composed of only one annular protrusion 230 to reduce the manufacturing difficulty; in a second preferred embodiment, the long creepage reinforcement portion is composed of multiple annular protrusions 230 of different heights, wherein the creepage distance of adjacent annular protrusions 230 is smaller than the creepage distance of the spaced annular protrusions 230, so as to maximize the creepage distance and avoid conductivity phenomena in the spaced annular protrusions 230. For example, a high-low-high three-annular protrusion 230 structure or a high-low-low-high four-annular protrusion 230 structure can be used to further increase the creepage path distance and further improve the chip's withstand voltage capability.

[0101] By setting the annular protrusion 230, the edge strength of the chip 200 can be increased, improving its anti-friction ability and preventing edge damage that could lead to product defects, thus ensuring the quality of the chip 200. Simultaneously, it can further reduce the electrical strength at the edge of the chip 200, effectively preventing arcing on both sides of the chip 200 electrodes due to stronger electric field strength and higher voltage at the edge. This improves the lifespan and electrical performance of the surface mount capacitor. The minimum distance between the second connection terminal 322 and the chip 200 can be the vertical distance between the second connection terminal 322 and the highest annular protrusion 230.

[0102] When processing chip 200, the annular protrusion 230 can be processed first by cutting, then the second step surface 220 can be processed, and then the first step surface 210 can be processed.

[0103] In some embodiments, the outer surface of the annular protrusion 230 is connected to the step surface by a first fillet, and the inner surface of the annular protrusion 230 is connected to the step surface, or adjacent step surfaces, by a second fillet. Both the first and second fillets include two tangentially connected arc segments. As an example only, the step surface may include a first step surface 210 and a second step surface 220. The outer surface of the annular protrusion 230 is connected to the second step surface 220 by a first fillet, and the inner surface of the annular protrusion 230 is connected to the second step surface 220, and the second step surface 220 is connected to the first step surface 210 by a second fillet.

[0104] The arc consists of a first arc and a second arc, with the diameter of the second arc being larger than the diameter of the first arc.

[0105] In this embodiment of the invention, since the strongest electric field is located at the chip edge, and the weakest point during powder pressing and ceramic sintering is also at the chip edge, different curvature designs are used to distribute the electric field more evenly to the edge, reducing the electric field intensity at the chip edge and thus improving the overall reliability of the product. Furthermore, all curved edges are designed with rounded corners to avoid tip discharge issues.

[0106] The first rounded corner includes a first circular arc and a second circular arc that are tangent to each other. The first circular arc is tangent to the annular protrusion 230, and the second circular arc is tangent to the second step surface 220.

[0107] The second rounded corner consists of two tangent first arcs.

[0108] In some embodiments, the radius of the first arc is determined based on the number of step surfaces. In some embodiments, the worker can calculate the radius of the arc using a fourth preset algorithm. The fourth preset algorithm may include formula (4);

[0109]

[0110] Where S represents the number of stepped surfaces, D represents the maximum thickness of the chip 200 during design, and U represents the maximum voltage during design. For the electrical strength of chip 200, As the first coefficient, regarding S, D, U, , For more details, please refer to the relevant descriptions above. This is the radius of the first arc. The radius of the second arc is determined based on the radius of the first arc. For example, a preset increment value is added to the radius of the first arc. This preset increment value is a pre-defined value that can be set according to actual needs.

[0111] For example only, the radius of the first arc is 0.05 mm, and the radius of the second arc is 0.07 mm. The outer side of the annular protrusion 230 is connected to the second step 220 by a first arc of 0.05 mm and a second arc of 0.07 mm. The inner side of the annular protrusion 230 is connected to the second step 220 by two first arcs of 0.05 mm each. The second step 220 is connected to the first step 210 by two first arcs of 0.05 mm each.

[0112] In some embodiments, the second step 220 and the first step 210 can also be transitioned by a conical surface, or the welding surface of the chip 200 may include a first step surface welded to the welding part 330 and a conical surface surrounding the first step surface. The cone angle corresponding to the conical surface can be greater than 90°, for example, 120°, 150°, 170° or other values, and the specific value can be set according to actual needs. By using a conical surface, along the direction from the center to the edge of the chip 200, the change amplitude of the electric field can be smaller and more uniform, avoiding the phenomenon of local electric field concentration, which is beneficial to improving the overall performance of the surface mount capacitor.

[0113] The arc-shaped design of the connecting part 320 also helps to prevent the connecting part 320 from contacting the annular protrusion 230 and / or the second step surface 220, so as to ensure electrical performance.

[0114] In some embodiments, the number of annular protrusions 230 can be determined based on preset physical strength requirements and preset electrical parameters of the chip 200.

[0115] The preset physical strength requirements describe the physical strength requirements of chip 200. Physical strength can include at least one of wear resistance, strength, and hardness. These preset physical strength requirements are design parameters used when designing chip 200 and can be determined in various ways, such as based on historical data or set according to actual needs.

[0116] Preset electrical parameters describe the electrical performance requirements of chip 200. These electrical parameters may include at least one of voltage, current, resistance, power, and frequency. These preset electrical parameters are design parameters used when designing chip 200 and can be determined in various ways, such as based on historical data or set according to actual needs.

[0117] In some embodiments, the number of annular protrusions 230 can be determined in a variety of ways. For example, staff can build a data table based on historical data. The data table may include the number of configurations, preset physical strength, preset electrical parameters and their corresponding relationships. Staff can determine the number of configurations by querying the data table based on the preset physical strength and preset electrical parameters.

[0118] The number of annular protrusions is determined according to different preset physical strength requirements and preset electrical parameters. This allows for the targeted design and fabrication of chip 200 while meeting the actual usage requirements of chip 200, ensuring the processing quality of chip 200, facilitating precise control of production steps and material usage, ensuring production efficiency and avoiding material waste.

[0119] After the encapsulation part 100 is injection molded, it needs to be demolded to separate the encapsulation part 100 from the mold. However, during the cooling process of the injection material, the injection material may adhere to the mold to a certain extent, thereby increasing the resistance during demolding.

[0120] In some embodiments, such as Figure 2 As shown, the circumferential side surface of the encapsulation portion 100 includes a first inclined surface 110 and a second inclined surface 120 that are connected to each other. The connection between the first inclined surface 110 and the second inclined surface 120 is inclined outward in a direction away from the encapsulation portion 100. The first inclined surface 110 and the second inclined surface 120 may be symmetrically distributed.

[0121] By setting the first inclined surface 110 and the second inclined surface 120, during the demolding process, when the mold is separated from the packaging part 100, the demolding direction can have a certain angle with the first inclined surface 110 or the second inclined surface 120, so that the packaging part 100 can be completely separated from the mold, avoiding friction between the mold and the packaging part 100 during the demolding process, thereby reducing the resistance during demolding, improving the smoothness and reliability of the demolding action, and helping to improve the surface quality of the product and provide protection for the mold.

[0122] In some embodiments, the corners of the outer surface of the encapsulation portion 100 can be rounded. For example, the connection between the first inclined surface 110 and the second inclined surface 120, the connection between the first inclined surface 110 and the end face of the encapsulation portion 100, and the connection between the second inclined surface 120 and the end face of the encapsulation portion 100 can all be rounded. This helps to avoid stress concentration in the encapsulation portion 100 and also helps to prevent wear at the corners.

[0123] In some embodiments, the angle between the first inclined plane 110 and the second inclined plane 120 is a preset value, such as 10°, 11°, 12° or other values, and the specific value can be set according to actual needs.

[0124] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0125] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

Claims

1. A surface mount capacitor, characterized in that, include: The encapsulation portion has two opposing end faces and a side surface distributed circumferentially between the two end faces; The chip, located within the package, has two opposing solder surfaces; The package includes external pins, a connecting portion, and a multi-protrusion soldering portion; the multi-protrusion soldering portion and the connecting portion are disposed within the package, and the connecting portion connects the multi-protrusion soldering portion and the external pin; there are two pins, and the corresponding multi-protrusion soldering portion of each pin is spirally and symmetrically connected to the corresponding soldering surface of the chip; the two external pins are respectively disposed on the outer sides of opposite sides of the package along the circumferential direction. The external pin includes a support plate and a first bent portion and a second bent portion disposed on opposite sides of the support plate; The first bending portion bends along a direction close to the encapsulation portion and is connected to the connecting portion; the second bending portion bends along a direction away from the encapsulation portion. The first bending portion and the support plate are provided with a first groove, and the first groove divides the first bending portion into two first connecting feet; Each connecting part has an integrally formed first connecting end and second connecting end; the two legs of the first connecting end are respectively connected to the corresponding first connecting legs; The multi-protrusion welded part has multiple protrusions distributed circumferentially, one of which is connected to the second connecting end; At least a portion of the second connection end is parallel to the corresponding welding surface, and the minimum distance between the second connection end and the chip is determined according to a preset electrical breakdown parameter; The first connection end is arc-shaped, and the curvature of the first connection end is set based on the minimum distance between the second connection end and the chip; The second bend is provided with a second groove, which is used to divide the second bend into two second connecting feet.

2. The surface mount capacitor according to claim 1, characterized in that, The chip is disk-shaped, and the welding surface has multiple stepped surfaces. The number of stepped surfaces is determined based on the first preset electrical strength of the chip. Along the direction from the center to the edge of the welding surface, the distance between the multiple stepped surfaces and the connection part decreases sequentially.

3. The surface mount capacitor according to claim 2, characterized in that, The plurality of stepped surfaces includes at least a first stepped surface and a second stepped surface; The second step surface is distributed in a ring around the circumference of the first step surface; the multi-protrusion welding part is connected to the first step surface; the second step surface is provided with a long creepage reinforcement part, the long creepage reinforcement part including at least one annular protrusion.

4. The surface mount capacitor according to claim 3, characterized in that, The outer side of the annular protrusion is connected to the step surface by a first rounded corner, and the inner side of the annular protrusion is connected to the step surface or adjacent step surfaces by a second rounded corner. Both the first rounded corner and the second rounded corner include two tangent arc segments, and the radius of the arc is determined based on the number of step surfaces. The arc includes a first arc and a second arc, wherein the diameter of the second arc is larger than the diameter of the first arc.

5. The surface mount capacitor according to claim 3 or 4, characterized in that, The number of annular protrusions is determined based on the chip's preset physical strength requirements and preset electrical parameters.

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