Multilayer ceramic dielectric capacitor and preparation method thereof

Abstract

The invention relates to a multilayer ceramic dielectric capacitor, which comprises a laminated body with ceramic dielectric, and a first external electrode and a second external electrode formed on two opposite end surfaces of the laminated body, a first inner electrode and a second inner electrode which are alternately stacked in the thickness direction of the laminated body and are not in contact with each other are arranged in the laminated body, the first inner electrode is connected with the first outer electrode, the second inner electrode is connected with the second outer electrode, and a heat dissipation layer is further arranged in the laminated body. The heat dissipation layer is located between the first inner electrode and the second inner electrode which are adjacent, the heat dissipation layer extends to the side face, except the end face where the first outer electrode and the second outer electrode are located, of the laminated body and is exposed, and the heat conductivity of the heat dissipation layer is larger than that of the ceramic medium. The multilayer ceramic dielectric capacitor provided by the invention can effectively dissipate heat inside, thereby improving the reliability and stability of the device and prolonging the service life of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitors, and in particular to a multi-layer ceramic capacitor and a method for manufacturing the multi-layer ceramic capacitor. Background Art

[0002] An MLCC (Multi-layer Ceramic Capacitor) is a capacitor made by laminating ceramic dielectrics printed with metal electrodes (i.e., internal electrodes) in a misaligned manner, sintering them at a high temperature once to form a ceramic laminate, and then sealing metal layers (external electrodes) at both ends of the chip. It has the advantages of small size, large capacitance, good high-frequency characteristics, etc., and is widely used in many electronic devices.

[0003] Due to the poor heat dissipation performance of the ceramic dielectric material inside the MLCC, problems are likely to occur in high-power or high-frequency application scenarios. When a large current passes through the circuit, heat is difficult to dissipate quickly, which will cause the internal temperature of the capacitor to rise sharply. This may lead to a drift in the capacitance value, deviating from its nominal value, and affecting the normal filtering and coupling effects of the circuit. Being in a high-temperature state for a long time will also accelerate the aging of the ceramic dielectric, reduce its insulation performance, increase dielectric loss, and may even cause a short-circuit fault, seriously affecting the reliability and stability of the entire electronic system and shortening the service life of the device. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to overcome the defects or deficiencies of the prior art, and provide a multi-layer ceramic capacitor that can effectively dissipate heat inside, thereby improving the reliability and stability of the device and extending the service life of the device.

[0005] A multi-layer ceramic capacitor includes a laminate composed of ceramic dielectrics, and a first external electrode and a second external electrode formed on opposite end faces of the laminate; first internal electrodes and second internal electrodes that are alternately stacked in the thickness direction of the laminate and do not contact each other are provided in the laminate, the first internal electrodes are connected to the first external electrode, the second internal electrodes are connected to the second external electrode, a heat dissipation layer is further provided in the laminate, the heat dissipation layer is located between adjacent first internal electrodes and second internal electrodes, and the heat dissipation layer extends to the side surface of the laminate except for the end faces where the first external electrode and the second external electrode are located and is exposed, wherein the thermal conductivity of the heat dissipation layer is greater than the thermal conductivity of the ceramic dielectric.

[0006] Compared with the prior art, in the multi-layer ceramic capacitor of the present invention, a heat dissipation layer with a thermal conductivity greater than that of the ceramic dielectric is provided in the stacked body to form a heat dissipation channel inside the ceramic dielectric of the stacked body, and direct the heat to the side surfaces of the stacked body except the end surfaces where the external electrodes are located, so as to effectively dissipate the heat inside the capacitor, thereby improving the reliability and stability of the device and extending the service life of the device.

[0007] In one embodiment, the heat dissipation layer is made of a metal material.

[0008] In one embodiment, the first external electrode and the second external electrode are provided on the opposite end surfaces of the stacked body along a first direction, and the heat dissipation layer extends to the opposite first side surface and second side surface of the stacked body along a second direction, wherein the second direction is perpendicular to the first direction; the shortest distance from the end portions of the heat dissipation layer exposed on the first side surface and the second side surface to the two external electrodes is a first distance; the shortest distance from the portion of the heat dissipation layer located inside the stacked body to the two external electrodes is a second distance; the first distance is greater than the creepage distance between the first external electrode and the second external electrode, and the second distance is greater than or equal to the withstand voltage safety distance between adjacent first internal electrodes and second internal electrodes.

[0009] In one embodiment, the multi-layer ceramic capacitor further includes a heat dissipation extension piece, the heat dissipation extension piece is formed on the side surfaces of the stacked body except the end surfaces where the first external electrode and the second external electrode are located, the heat dissipation extension piece is connected to the heat dissipation layer but does not contact the first external electrode and the second external electrode; wherein, the thermal conductivity of the heat dissipation extension piece is greater than that of the ceramic dielectric.

[0010] In one embodiment, the heat dissipation extension piece is formed on the first side surface and the second side surface and is respectively connected to the two ends of the heat dissipation layer along the second direction.

[0011] In one embodiment, the distance between the heat dissipation layer and the adjacent first internal electrode is the same as the distance from the heat dissipation layer to the adjacent second internal electrode.

[0012] In addition, the present invention also provides a preparation method for preparing the above multi-layer ceramic capacitor, including the following steps:

[0013] S1: Prepare a first ceramic film, a second ceramic film and a third ceramic film, wherein, a first internal electrode is formed on the surface of the first ceramic film, a second internal electrode is formed on the surface of the second ceramic film, and a heat dissipation layer is formed on the surface of the third ceramic film;

[0014] S2: Stack the first ceramic diaphragm, the second ceramic diaphragm, and the third ceramic diaphragm alternately in the thickness direction, with the third ceramic diaphragm positioned between adjacent first and second ceramic diaphragms, and form a stacked green body after pressing and cutting;

[0015] S3: Debind and sinter the stacked green body to obtain a stacked fired body;

[0016] S4: Chamfer the stacked fired body to expose the first internal electrode, the second internal electrode, and the heat dissipation layer, and then seal and fire the first end face and the second end face of the stacked fired body that are opposite to each other in the first direction to obtain a multilayer ceramic capacitor.

[0017] Compared with the prior art, the preparation method of the multilayer ceramic capacitor of the present invention alternately stacks ceramic diaphragms with internal electrodes formed on the surface and ceramic diaphragms with heat dissipation layers formed on the surface, with the ceramic diaphragms with heat dissipation layers formed on the surface positioned between two adjacent ceramic diaphragms with internal electrodes formed on the surface, forming a heat dissipation channel within the ceramic dielectric to conduct heat out of the capacitor, thereby improving the heat dissipation effect inside the capacitor.

[0018] In one embodiment, in step S4, after chamfering is completed, a heat dissipation extension piece is formed on the side surface of the stacked fired body except for the first end face and the second end face, and the heat dissipation extension piece is connected to each heat dissipation layer.

[0019] In one embodiment, in step S2, the sum of the thicknesses of the ceramic dielectric in the third ceramic diaphragm and the ceramic dielectric in the first ceramic diaphragm or the second ceramic diaphragm is greater than the withstand voltage safety distance.

[0020] In one embodiment, in step S2, the thickness of the ceramic dielectric in the third ceramic diaphragm is the same as the thicknesses of the ceramic dielectrics in the first ceramic diaphragm and the second ceramic diaphragm.

[0021] For better understanding and implementation, the present invention will be described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Structural schematic diagrams (different angles) of existing MLCCs: Figure 1 (a) Front view of the MLCC; Figure 1 (b) Perspective view of the first internal electrode in the MLCC from a top view angle; Figure 1 (c) Perspective view of the second internal electrode in the MLCC from a top view angle; Figure 1 (d): Cross-sectional view of the MLCC;

[0023] Figure 2Stereogram of an embodiment of the multi-layer ceramic capacitor of the present invention;

[0024] Figure 3 Structural schematic diagram (different angles) of an embodiment of the multi-layer ceramic capacitor of the present invention: Figure 3 (a) Front view of the multi-layer ceramic capacitor; Figure 3 (b) Top view of the multi-layer ceramic capacitor; Figure 3 (c) Cross-sectional view of the multi-layer ceramic capacitor;

[0025] Figure 4 Top view of another embodiment of the multi-layer ceramic capacitor of the present invention;

[0026] Figure 5 Structural schematic diagram (different angles) of still another embodiment of the multi-layer ceramic capacitor of the present invention: Figure 5 (a) Front view of the multi-layer ceramic capacitor; Figure 5 (b) Rear view of the multi-layer ceramic capacitor; Figure 5 (c) Top view of the multi-layer ceramic capacitor; Figure 5 (d) Bottom view of the multi-layer ceramic capacitor;

[0027] Figure 6 Top views of the first ceramic film, the second ceramic film, and the third ceramic film in the preparation method of the multi-layer ceramic capacitor of the present invention: Figure 6 (a) Top view of the first ceramic film; Figure 6 (b) Top view of the second ceramic film; Figure 6 (c) Top view of the third ceramic film;

[0028] Figure 7 Front views of the first ceramic film, the second ceramic film, and the third ceramic film in the preparation method of the multi-layer ceramic capacitor of the present invention: Figure 7 (a) Front view of the first ceramic film; Figure 7 (b) Front view of the second ceramic film; Figure 7 (c) Front view of the third ceramic film;

[0029] Figure 8 Structural schematic diagram of the stacked green body formed in the preparation method of the multi-layer ceramic capacitor of the present invention.

[0030] Reference numerals:

[0031] 10. Stacked body; 10a. First side; 10b. Second side; 10c. Third side; 10d. Fourth side; 101. First ceramic diaphragm; 102. Second ceramic diaphragm; 103. Third ceramic diaphragm; 104. Fourth ceramic diaphragm; 1000. Ceramic medium; 1010. First internal electrode; 1020. Second internal electrode; 1030. Heat dissipation layer;

[0032] 201. First external electrode; 202. Second external electrode;

[0033] 30. Heat dissipation extension piece;

[0034] D1. First direction; D2. Second direction; D3. Thickness direction. Detailed implementation mode

[0035] As Figure 1 As shown, an MLCC generally includes a stacked body 10 formed by alternately laminating ceramic media printed with a first internal electrode 1010 and a second internal electrode 1020 along the thickness direction D3, and a first external electrode 201 and a second external electrode 202 formed on opposite end faces of the stacked body 10 along the first direction D1. The main component material of the stacked body 10 is the ceramic medium 1000. Since the ceramic medium 1000 has poor heat dissipation performance, when a large current passes through the circuit, the heat of the ceramic medium 1000 part is difficult to dissipate quickly, causing the internal temperature of the capacitor to rise sharply. Under long-term high-temperature conditions, the ceramic medium 1000 will age, affecting the performance of the capacitor, and further affecting the reliability, stability, and service life of the capacitor.

[0036] Based on this, the present invention forms a heat dissipation channel inside the ceramic medium of the stacked body by providing a heat dissipation layer with a thermal conductivity greater than that of the ceramic medium in the stacked body, guiding the heat to the side surfaces of the stacked body except for the end faces where the external electrodes are located, improving the heat dissipation effect inside the capacitor; further, by designing the shape of the heat dissipation layer, maximizing the contact area between the heat dissipation layer and the ceramic medium, while ensuring a certain safety distance between the heat dissipation layer and the two external electrodes; furthermore, by providing a heat dissipation extension piece connected to the heat dissipation layer on the side surface adjacent to the external electrode, increasing the heat dissipation area, and further improving the heat dissipation effect.

[0037] In addition, the present invention also provides a method for manufacturing the above-mentioned multi-layer ceramic capacitor. By alternately stacking ceramic diaphragms with inner electrodes formed on their surfaces and ceramic diaphragms with heat dissipation layers formed on their surfaces, the ceramic diaphragms with heat dissipation layers formed on their surfaces are located between two adjacent ceramic diaphragms with inner electrodes formed on their surfaces, so as to form heat dissipation channels in the ceramic dielectric and conduct heat out of the capacitor to improve the heat dissipation effect inside the capacitor. At the same time, the arrangement of the heat dissipation layer is used to increase the degumming channels, effectively improve the degumming efficiency and degumming effect, and effectively avoid defects such as delamination and cracking of the ceramic dielectric after sintering due to poor degumming.

[0038] The following will describe the solution of the present invention in detail with reference to the accompanying drawings.

[0039] Figures 2-3 The specific structure of an embodiment of the multi-layer ceramic capacitor of the present invention is shown. As Figures 2-3 shown, a multi-layer ceramic capacitor according to an embodiment of the present invention includes a stack 10 composed of a ceramic dielectric 1000, and external electrodes formed on opposite end faces of the stack 10 along a first direction D1, namely a first external electrode 201 and a second external electrode 202. The stack 10 is provided with m layers of first inner electrodes 1010 and n layers of second inner electrodes 1020, where m and n are both positive integers, m≥1, n≥1, and |m - n|≤1. Here, the number of the first inner electrodes 1010 and the number of the second inner electrodes 1020 may differ by one layer, or as Figure 3 (c) shows, the number of the first inner electrodes 1010 is the same as the number of the second inner electrodes 1020. The first inner electrodes 1010 and the second inner electrodes 1020 are alternately stacked along the thickness direction of the stack 10, and each first inner electrode 1010 is connected to the first external electrode 201, and each second inner electrode 1020 is connected to the second external electrode 202.

[0040] To improve the heat dissipation effect inside the stack 10 (especially for the ceramic dielectric 1000), the stack 10 is further provided with a heat dissipation layer 1030, and the heat dissipation layer 1030 is located between adjacent first inner electrodes 1010 and second inner electrodes 1020. Both ends of the heat dissipation layer 1030 along a second direction D2 extend to a first side surface 10a and a second side surface 10b of the stack 10 adjacent to the two external electrodes and are exposed. The thickness of the heat dissipation layer 1030 is preferably the same as that of the first inner electrodes 1010 and the second inner electrodes 1020. In this embodiment, the thickness of the heat dissipation layer 1030 is specifically ≤3μm. If the thickness of the heat dissipation layer 1030 is too thin, the area exposed on the first side surface 10a and the second side surface 10b is small, affecting the heat conduction efficiency; if it is too thick, delamination will occur between the heat dissipation layer 1030 and the ceramic dielectric 1000, affecting the device performance. The shape of the heat dissipation layer 1030 can be as Figure 3(b) The rectangle shown can also be any one of a circle, a triangle, a square, a rectangle, a quadrilateral, or a polygon. The heat dissipation layer 1030 in this embodiment is a rectangle, and the cross-section of the rectangular heat dissipation layer 1030 along the thickness direction D3 of the laminate 10 is adapted to maximize the contact area with the ceramic dielectric 1000. The heat dissipation layer 1030 is made of a metal material such as copper, nickel, or silver with a thermal conductivity greater than that of the ceramic dielectric 1000. In this way, by providing a heat dissipation layer 1030 with high thermal conductivity in the ceramic dielectric 1000 of the laminate 10, the heat generated during the use of the capacitor is directed to the outside of the capacitor, enhancing the heat dissipation effect inside the device and improving the reliability, stability, and service life of the capacitor.

[0041] Preferably, the distance from each heat dissipation layer 1030 to the adjacent first inner electrode 1010 is the same as the distance to the adjacent second inner electrode 1020. In this way, it can be ensured that the heat dissipation effect of each heat dissipation layer 1030 on the ceramic dielectric 1000 on both sides of it is uniform.

[0042] The larger the contact area between the heat dissipation layer 1030 and the ceramic dielectric 1000 of the laminate 10, the higher the heat conduction efficiency and the better the heat dissipation effect. However, when the end face of the laminate 10 along the first direction D1 is dip-sealed, part of the electrode paste will cover the positions near the end face of the first side 10a and the second side 10b of the laminate 10, so that the first outer electrode 201 and the second outer electrode 202 formed after firing are partially covered at the positions near the end face of the first side 10a and the second side 10b. To prevent the heat dissipation layer 1030 extending to and exposed on the first side 10a and the second side 10b from contacting the first outer electrode 201 and the second outer electrode 202, in some embodiments, as Figure 4 shown, the heat dissipation layer 1030 is in the shape of a virtual rectangle with cut corners at four corner positions, making the overall heat dissipation layer 1030 in the shape of a Figure 4 "cross". The shortest distance between the two end portions of the heat dissipation layer 1030 exposed on the first side 10a and the second side 10b and the first outer electrode 201 and the second outer electrode 202 is the first distance L1. The first distance L1 is greater than the creepage distance between the first outer electrode 201 and the second outer electrode 202. The shortest distance between the part of the heat dissipation layer 1030 located inside the laminate 10 and the first outer electrode 201 and the second outer electrode 202 is the second distance L2, and the second distance L2 is greater than the withstand voltage safety distance between the adjacent first inner electrode 1010 and the second inner electrode 1020. Here, as Figure 4As shown, the shortest distances from the portion of the heat dissipation layer 1030 inside the laminate 10 to the same external electrode specifically include the distances from the two end portions of the heat dissipation layer 1030 along the first direction D1 to the first external electrode 201 and the second external electrode 202 located on the two end faces, and the distances from the edge contours of the relative two sides of the heat dissipation layer 1030 along the second direction D2 (i.e., the portions not exposed on the first side face 10a and the second side face 10b) to the first external electrode 201 and the second external electrode 202 located on the first side face 10a and the second side face 10b. Such a structural arrangement can, on the one hand, enable the heat dissipation layer 1030 to have a large contact area with the ceramic dielectric 1000, thereby efficiently realizing heat conduction and improving the heat dissipation efficiency; on the other hand, it can prevent the creepage phenomenon caused by the too-close distance between the exposed portion of the heat dissipation layer 1030 and the two external electrodes, and also avoid the electric breakdown or leakage phenomenon due to the too-close distance between the portion of the heat dissipation layer 1030 inside the laminate 10 and the two external electrodes, thus ensuring the electrical safety of the capacitor during use.

[0043] In the above-mentioned multi-layer ceramic capacitor, the two ends of the heat dissipation layer 1030 along the second direction D2 extend to the first side face 10a and the second side face 10b of the laminate 10 and are exposed in the air to direct the heat generated inside the laminate 10 to the outside of the capacitor. However, as mentioned above, since the thickness of the heat dissipation layer 1030 cannot be too thick, the contact area between its exposed portion and the air is small, affecting the heat dissipation efficiency. To further improve the heat dissipation efficiency, heat dissipation extension pieces 30 are also formed on the surface of the laminate 10. As Figure 5 shown, the heat dissipation extension pieces 30 at least cover the exposed areas of the heat dissipation layer 1030 on the first side face 10a and the second side face 10b of the laminate 10 and are connected to the end portions of the heat dissipation layer 1030 extending to the first side face 10a and the second side face 10b, but the heat dissipation extension pieces 30 do not contact the first external electrode 201 and the second external electrode 202. To avoid the creepage phenomenon between the heat dissipation extension pieces 30 and the first external electrode 201 and the second external electrode 202 due to the too-close distance, the shortest distances from the heat dissipation extension pieces 30 to the first external electrode 201 and the second external electrode 202 are both greater than the creepage distance between the first external electrode 201 and the second external electrode 202.

[0044] Of course, the heat dissipation extension pieces 30 can only cover the first side face 10a and the second side face 10b, or can be as Figure 5As shown, it covers the first side 10a, the second side 10b, the third side 10c, and the fourth side 10d at the same time. The heat conduction rate of the heat dissipation extension piece 30 is greater than that of the ceramic medium 1000. It can be made of the same metal material as the heat dissipation layer 1030, or can be made of the same electrode paste and process as the first external electrode 201 and the second external electrode 202. In this way, by arranging the heat dissipation extension piece 30 connected to the heat dissipation layer 1030 in the laminate 10, the contact area between the heat dissipation layer 1030 and the external environment of the capacitor is increased, so as to more quickly lead the heat inside the laminate 10 to the external environment, improve the heat dissipation efficiency, and further enhance the heat dissipation effect.

[0045] In addition, to prepare the above-mentioned multi-layer ceramic capacitor, an embodiment of the present invention provides a preparation method. Taking the embodiment in which the heat dissipation layer 1030 is rectangular as an example, the preparation method includes the following steps:

[0046] S1: A first ceramic film 101, a second ceramic film 102, and a third ceramic film 103, wherein a first internal electrode 1010 is formed on the surface of the first ceramic film 101, a second internal electrode 1020 is formed on the surface of the second ceramic film 102, and a heat dissipation layer 1030 is formed on the surface of the third ceramic film 103;

[0047] Specifically, as Figures 6-7 shown, prepare a sheet-like ceramic medium 1000, and print the electrode paste on the corresponding surface of the ceramic medium 1000 according to the preset pattern of the first internal electrode 1010 or the second internal electrode 1020 through a printing screen, to obtain the first ceramic film 101 with the first internal electrode 1010 formed on the surface as shown in Figure 6 (a), the second ceramic film 102 with the second internal electrode 1020 formed on the surface as shown in Figure 6 (b); and print the metal paste on the corresponding surface of the ceramic medium 1000 according to the preset pattern of the heat dissipation layer 1030, to obtain the third ceramic film 103 with the heat dissipation layer 1030 formed on the surface as shown in Figure 6 (c); wherein, the sum of the thicknesses of the ceramic medium 1000 of the third ceramic film 103 and the ceramic medium 1000 of the first ceramic film 101 or the ceramic medium 1000 of the second ceramic film 102 is greater than the withstand voltage safety distance, to avoid electric breakdown or leakage between the first internal electrode 1010 and the second internal electrode 1020 after the first ceramic film 101, the second ceramic film 102, and the third ceramic film 103 are laminated.

[0048] Preferably, the thicknesses of the ceramic medium 1000 used to form the first ceramic diaphragm 101, the second ceramic diaphragm 102, and the third ceramic diaphragm 103 are the same, and are half of the thickness of the ceramic medium 1000 used to prepare traditional MLCCs. In this way, it is ensured that the thickness of the capacitor will not increase after the first ceramic diaphragm 101, the second ceramic diaphragm 102, and the third ceramic diaphragm 103 are stacked, and at the same time, the thicknesses of the ceramic medium 1000 on both adjacent sides of each heat dissipation layer 1030 are the same, ensuring that the heat conduction efficiency of the heat dissipation layer 1030 for the ceramic medium 1000 on both adjacent sides is equivalent, thereby ensuring the uniformity of heat dissipation.

[0049] S2: Alternately stack the first ceramic diaphragm 101, the second ceramic diaphragm 102, and the third ceramic diaphragm 103 along the thickness direction D3, with the third ceramic diaphragm 103 located between the adjacent first ceramic diaphragm 101 and the second ceramic diaphragm 102, and form a stacked green body after pressing and cutting;

[0050] Specifically, the first ceramic diaphragm 101 shown in Figure 7 (a), the second ceramic diaphragm 102 shown in Figure 7 (b), and the third ceramic diaphragm 103 shown in Figure 7 (c) are alternately stacked along the thickness direction D3 to form a stacked substrate, and one or more layers of fourth ceramic diaphragms 104 are stacked on the top of the stacked substrate, and then the stacked substrate is pressed and cut to form a stacked green body as shown in Figure 8 ; wherein, the third ceramic diaphragm 103 is located between the adjacent first ceramic diaphragm 101 and the second ceramic diaphragm 102, and the fourth ceramic diaphragm 104 is a bare-board ceramic medium 1000 on which no internal electrodes or heat dissipation layers 1030 are formed. Taking the stacked green body shown in Figure 8 as an example, from bottom to top are the first ceramic diaphragm 101, the third ceramic diaphragm 103, the second ceramic diaphragm 102, the third ceramic diaphragm 103, the first ceramic diaphragm 101, and one layer of fourth ceramic diaphragm 104 is also stacked at the topmost position, and a stacked green body with ceramic medium 1000 on both the upper and lower surfaces is formed after pressing and cutting.

[0051] S3: Debind and sinter the stacked green body to obtain a stacked fired body;

[0052] The main purpose of debinding is to decompose and discharge the organic binders (such as PVB resin and DOP, etc.) added to the ceramic powder to play a binding role during the preparation of the ceramic medium 1000 through heat treatment, so as to avoid defects such as delamination and cracking caused by the rapid volatilization of organic substances during sintering.

[0053] In the production practice, the inventor found that the debinding efficiency of the stacked green body obtained through step S2 is higher than that of the stacked green body of traditional MLCCs, and the debinding effect is better. After analysis, it is found that this is because a heat dissipation layer 1030 with a certain thickness is formed on the surface of the third ceramic film 103, creating a gap between the ceramic medium 1000 of the third ceramic film 103 and the ceramic medium 1000 of the adjacent first ceramic film 101 or second ceramic film 102. Such a structural design provides more debinding channels for debinding. Therefore, compared with the stacked green body of traditional MLCCs with the same volume, preparing a multilayer ceramic capacitor with the above structure can effectively shorten the debinding time, greatly improve the production efficiency, and has a good debinding effect, effectively avoiding defects such as delamination and cracking of the ceramic after sintering due to poor debinding.

[0054] The main purpose of sintering is to combine the ceramic medium 1000 of the capacitor and the internal electrodes into a solid multilayer structure at high temperature to ensure the performance and stability of the capacitor. After debinding, the stacked green body is subjected to high-temperature sintering to obtain a stacked fired body.

[0055] S4: Chamfer the stacked fired body to expose the first internal electrode 1010, the second internal electrode 1020, and the heat dissipation layer 1030, and then seal and fire the first end face and the second end face of the stacked fired body along the first direction D1 to obtain the Figure 2 multilayer ceramic capacitor as shown.

[0056] Since the stacked fired body after sintering into porcelain has distinct edges and corners, which is not conducive to connecting with the external electrodes and also not conducive to the heat dissipation layer 1030 being exposed to the external environment, it is necessary to perform grinding and chamfering treatment on it. The chamfering process is to place the ceramic fired body, water, and grinding medium in a chamfering tank and move them through methods such as ball milling and planetary milling to remove the burrs on the surface of the stacked fired body, make the surface of the stacked fired body smooth, and fully expose the internal electrodes at both end faces of the stacked fired body along the first direction D1 for connection with the external electrodes. At the same time, the heat dissipation layer 1030 of the stacked fired body along the second direction D2 is also fully exposed to the external environment;

[0057] After chamfering, electrode paste is applied to the two end faces of the stacked fired body along its first direction D1 where the internal electrodes are exposed through processes such as dipping slurry or screen printing. After the electrode paste undergoes firing treatment, the first external electrode 201 and the second external electrode 202 are formed, and finally the Figure 2 multilayer ceramic capacitor as shown is obtained.

[0058] In the above preparation method, lamination, cutting, debinding, chamfering, sintering, sealing, and firing are all existing technologies and not the key technical improvements of the present invention, so no detailed description will be given here.

[0059] In an embodiment of the present invention, a method for manufacturing the above-mentioned multi-layer ceramic capacitor is provided. By alternately stacking a first ceramic film 101 with a first inner electrode 1010 formed on its surface, a second ceramic film 102 with a second inner electrode 1020 formed on its surface, and a third ceramic film 103 with a heat dissipation layer 1030 formed on its surface, the third ceramic film 103 is located between the first ceramic film 101 and the second ceramic film 102. The heat dissipation layer 1030 is used to conduct the heat of the ceramic dielectrics 1000 on both sides thereof to the outside of the capacitor, thereby improving the heat dissipation effect inside the capacitor. At the same time, without increasing the thickness of the laminate 10, the third ceramic film 103 provided between the first ceramic film 101 and the second ceramic film 102 increases the degumming channels, improves the degumming efficiency, and improves the degumming effect, effectively avoiding defects such as delamination and cracking of the ceramic dielectric 1000 after sintering due to poor degumming.

[0060] Further, in step S4, after chamfering is completed, a heat dissipation extension piece 30 is formed on the side surface of the laminated green body except for the first end surface and the second end surface, and the heat dissipation extension piece 30 is connected to each heat dissipation layer 1030;

[0061] Specifically, while dipping the electrode paste on the first end surface and the second end surface of the laminated green body along the first direction D1, the electrode paste is also coated or printed on the first side surface 10a, the second side surface 10b, the third side surface 10c, and the fourth side surface 10d of the laminated green body, and covers the heat dissipation layer 1030 exposed on the first side surface 10a and the second side surface 10b. After high-temperature end firing, a first outer electrode 201 and a second outer electrode 202 are formed, as well as a heat dissipation extension piece 30 covering the first side surface 10a, the second side surface 10b, the third side surface 10c, and the fourth side surface 10d. By providing the heat dissipation extension piece 30, the area for heat exchange between the heat dissipation layer 1030 and the external environment is enlarged, and the heat exchange efficiency is improved, thereby further enhancing the heat dissipation effect inside the capacitor.

[0062] Compared with the prior art, the multi-layer ceramic capacitor of the present invention forms a heat dissipation layer with a thermal conductivity greater than that of the ceramic dielectric in the laminate, so as to form a heat dissipation channel inside the ceramic dielectric of the laminate, direct the heat to the side of the laminate except the end face where the external electrode is located, and improve the heat dissipation effect inside the capacitor; further, by setting the shape of the heat dissipation layer, the contact area between the heat dissipation layer and the ceramic dielectric is maximized, and at the same time, a certain safety distance is ensured between the exposed part of the heat dissipation layer and the part located inside the laminate and the two external electrodes; furthermore, by providing a heat dissipation extension piece connected to the heat dissipation layer on the side adjacent to the external electrode, the heat dissipation area is increased, and the heat dissipation effect is further improved, thereby improving the reliability and stability of the device and extending the service life of the device. In addition, the present invention also provides a method for manufacturing the above multi-layer ceramic capacitor. By alternately stacking ceramic film sheets with internal electrodes formed on the surface and ceramic film sheets with heat dissipation layers formed on the surface, the ceramic film sheets with heat dissipation layers formed on the surface are located between two adjacent ceramic film sheets with internal electrodes formed on the surface, so as to form a heat dissipation channel inside the ceramic dielectric and export the heat outside the capacitor, improving the heat dissipation effect inside the capacitor; at the same time, by using the heat dissipation layer, the degumming channel is increased, the degumming efficiency is effectively improved, the degumming effect is improved, and defects such as delamination and cracking of the ceramic dielectric after sintering due to poor degumming are effectively avoided.

[0063] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that unless otherwise specified, "a plurality" means two or more; the terms "first", "second", "third", etc. are only used for distinction, and are not used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. The term "and / or" used herein means and includes any or all possible combinations of one or more of the associated listed items. When the above description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of the present application, for those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0064] The above embodiments only represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A multilayer ceramic capacitor, comprising a laminate (10) composed of a ceramic dielectric (1000), and a first external electrode (201) and a second external electrode (202) formed on opposite end surfaces of the laminate (10); the laminate (10) is provided with a first internal electrode (1010) and a second internal electrode alternately stacked along a thickness direction thereof and not in contact with each other, the first internal electrode (1010) being connected to the first external electrode (201), and the second internal electrode (1020) being connected to the second external electrode (202), characterized in that: A heat dissipation layer (1030) is also provided in the stack (10), and the heat dissipation layer (1030) is located between the adjacent first inner electrode (1010) and the second inner electrode (1020), and the heat dissipation layer (1030) extends to the side surfaces of the stack (10) other than the end surfaces where the first outer electrode (201) and the second outer electrode (202) are located, and is exposed, wherein the thermal conductivity of the heat dissipation layer (1030) is greater than the thermal conductivity of the ceramic medium (1000).

2. The multilayer ceramic capacitor according to claim 1, characterized in that: The heat dissipation layer (1030) is made of metal material.

3. The multilayer ceramic capacitor according to claim 1, characterized in that: The first external electrode (201) and the second external electrode (202) are arranged on opposite end surfaces of the stack (10) along a first direction, and the heat dissipation layer (1030) extends to opposite first side surfaces (10a) and second side surfaces (10b) of the stack (10) along a second direction, wherein the second direction is perpendicular to the first direction; The shortest distance between the ends of the heat dissipation layer (1030) exposed on the first side surface (10a) and the second side surface (10b) and the two external electrodes (201, 202) is a first distance; the shortest distance between the portion of the heat dissipation layer (1030) located inside the stack (10) and the two external electrodes (201, 202) is a second distance; The first distance is greater than a creepage distance between the first outer electrode (201) and the second outer electrode (202), and the second distance is greater than or equal to a withstand voltage safety distance between adjacent first inner electrodes (1010) and second inner electrodes (1020).

4. The multilayer ceramic capacitor according to claim 3, characterized in that: It also includes a heat dissipation extension sheet (30), which is formed on the side surface of the stack (10) except the end surface where the first external electrode (201) and the second external electrode (202) are located, and the heat dissipation extension sheet (30) is connected to the heat dissipation layer (1030), but does not contact the first external electrode (201) and the second external electrode (202); wherein the thermal conductivity of the heat dissipation extension sheet is greater than the thermal conductivity of the ceramic medium.

5. The multilayer ceramic capacitor according to claim 4, characterized in that: The heat dissipation extension sheet (30) is formed on the first side surface (10a) and the second side surface (10b), and is respectively connected to two ends of the heat dissipation layer (1030) along the second direction.

6. The multilayer ceramic capacitor according to claim 1, characterized in that: The distance between the heat dissipation layer (1030) and the adjacent first internal electrode (1010) is the same as the distance between the heat dissipation layer (1030) and the adjacent second internal electrode (1020).

7. A method for preparing a multilayer ceramic capacitor, characterized in that: The following steps are involved: S1: preparing a first ceramic diaphragm (101), a second ceramic diaphragm (102) and a third ceramic diaphragm (103), wherein a first internal electrode (1010) is formed on the surface of the first ceramic diaphragm (101), a second internal electrode (1020) is formed on the surface of the second ceramic diaphragm (102), and a heat dissipation layer (1030) is formed on the surface of the third ceramic diaphragm (103); S2: alternately stacking the first ceramic diaphragm (101), the second ceramic diaphragm (102), and the third ceramic diaphragm (103) in a thickness direction so that the third ceramic diaphragm (103) is located between the adjacent first ceramic diaphragm (101) and the second ceramic diaphragm (102), and forming a stacked green body after pressing and cutting; S3: debinding and sintering the stacked green compact to obtain a stacked cooked compact; S4: Chamfering the stacked blank to expose the first internal electrode (1010), the second internal electrode (1020) and the heat dissipation layer (1030), and then sealing and sintering the first end face and the second end face of the stacked blank opposite to each other along the first direction to obtain a multilayer ceramic capacitor.

8. The method for preparing a multilayer ceramic capacitor according to claim 7, characterized in that: In step S4, after chamfering is completed, a heat dissipation extension sheet (30) is formed on the side surface of the stacked blank except the first end surface and the second end surface, and the heat dissipation extension sheet (30) is connected to each of the heat dissipation layers (1030).

9. The method for preparing a multilayer ceramic capacitor according to claim 7, characterized in that: In step S2, the sum of the thicknesses of the ceramic medium (1000) in the third ceramic diaphragm (103) and the ceramic medium (1000) in the first ceramic diaphragm (101) or the ceramic medium (1000) in the second ceramic diaphragm (102) is greater than a withstand voltage safety distance.

10. The method for preparing a multilayer ceramic capacitor according to claim 9, characterized in that: In step S2, the thickness of the ceramic medium (1000) in the third ceramic diaphragm (103) is the same as the thickness of the ceramic medium (1000) in the first ceramic diaphragm (101) and the thickness of the ceramic medium (1000) in the second ceramic diaphragm (102).

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