A multilayer ceramic capacitor

Abstract

This invention relates to the field of capacitor technology and discloses a multilayer ceramic capacitor, comprising a ceramic body and end electrodes disposed on both end faces of the ceramic body. The end electrodes extend to two sides of the ceramic body, and the ends of the two end electrodes are disposed opposite each other with a distance between them. The ceramic body includes inner electrodes, a dielectric layer, and a first additional electrode. The inner electrodes are arranged in parallel, and a dielectric layer is disposed between two adjacent inner electrodes. One end of an inner electrode extends to and connects to one of the end electrodes. The first additional electrode is disposed between the other end of an inner electrode and the end of the other end electrode, and the first additional electrode is disposed at a corner of the dielectric layer. This invention provides a multilayer ceramic capacitor that can isolate the ends of the end electrodes from the ends of the inner electrodes through the first additional electrode, thereby reducing the degree of electric field concentration and reducing the risk of breakdown and burnout.

Description

Technical Field

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

[0002] Currently, please refer to Figure 1 This is a cross-sectional view of a prior art multilayer ceramic capacitor. End electrodes 2' are provided on both end faces 17' of the ceramic body 1', and the end electrodes 2' also extend to the upper surface 15' and lower surface 16' of the ceramic body 1'. The other two faces are the side faces of the ceramic body 1'. The end of the end electrode 2' extending to the side face of the ceramic body is referred to as the end of the end electrode 2'. The ceramic body includes a plurality of dielectric layers 12' stacked along the thickness direction of the ceramic body and an inner electrode 11' disposed between two adjacent dielectric layers 12'. The end of the inner electrode 11' away from the end face connected to it is referred to as the end of the inner electrode 11'.

[0003] In the prior art, the end electrodes are formed by impregnating a ceramic body with electrode paste. The end electrodes extend to the ends of the ceramic body, and due to the rheological changes of the electrode paste under the influence of gravity, they form sharp corners at the ends. These sharp corners face the direction of the inner electrode and are obliquely aligned with the ends of the inner electrode. This leads to an increased concentration of the electric field at these points, posing a risk of breakdown and burnout to the multilayer ceramic capacitor. Summary of the Invention

[0004] The purpose of this invention is to provide a multilayer ceramic capacitor that can improve the problem of electric field concentration and reduce the risk of breakdown and burnout.

[0005] To achieve the above objectives, the present invention provides a multilayer ceramic capacitor, comprising a ceramic body and end electrodes disposed on both end faces of the ceramic body. The end electrodes extend to two sides of the ceramic body, and the ends of the two end electrodes are disposed opposite each other with a distance between them. The ceramic body includes an inner electrode, a dielectric layer, and a first additional electrode. The inner electrodes are disposed in parallel, and the dielectric layer is disposed between two adjacent inner electrodes. One end of the inner electrode extends to and connects to one of the end electrodes. The other end of the inner electrode is disposed between the end of the other end electrode and the end of the other end electrode, and the first additional electrode is disposed at a corner of the dielectric layer.

[0006] Preferably, the side of the first additional electrode facing the inner electrode at the same height is configured with a curved profile.

[0007] Preferably, the connection between the first additional electrode and the end electrode is also located on the end face of the ceramic body.

[0008] Preferably, the corners of the first additional electrode are rounded.

[0009] Preferably, the end electrode also extends to the upper and lower surfaces of the ceramic body.

[0010] Preferably, the ceramic body further includes a second additional electrode, which is disposed between two adjacent dielectric layers between two adjacent inner electrodes. The second additional electrode is also disposed between two upper and lower first additional electrodes, and is also connected to the end electrode with the connection point located on the side of the ceramic body.

[0011] Preferably, the first additional electrode and the second additional electrode are the same size and shape.

[0012] Preferably, the connection between the second additional electrode and the end electrode is also located on the end face of the ceramic body.

[0013] Preferably, the multilayer ceramic capacitor further includes a protective electrode, which is disposed at both ends of the upper surface of the ceramic body and / or both ends of the lower surface of the ceramic body. The edge of the protective electrode away from the end of the ceramic body is straight, and the end electrode covers the protective electrode.

[0014] Preferably, the terminal electrode includes a bottom terminal, an intermediate terminal, and a surface terminal arranged sequentially from the inside to the outside. The bottom terminal located on the upper surface and the lower surface of the ceramic body is disposed on the outer surface of the protective electrode. The intermediate terminal located on the upper surface and the lower surface of the ceramic body is disposed on the bottom terminal and extends to the protective electrode. The intermediate terminal completely covers the bottom terminal and the protective electrode. The surface terminal located on the upper surface and the lower surface of the ceramic body is disposed on the intermediate terminal and completely covers the intermediate terminal. The first additional electrode is located between the end of the surface terminal and the end of the inner electrode.

[0015] This invention provides a multilayer ceramic capacitor, which has the following advantages compared with the prior art:

[0016] The multilayer ceramic capacitor of the present invention includes a ceramic body and end electrodes disposed on both end faces of the ceramic body. The ceramic body includes inner electrodes, a dielectric layer, and a first additional electrode. The inner electrodes are arranged in parallel, and a dielectric layer is disposed between two adjacent inner electrodes. One end of an inner electrode extends to and connects to one of the end electrodes. A first additional electrode is disposed between the other end of an inner electrode and the end of another end electrode, and the first additional electrode is disposed at a corner of the dielectric layer. With this structure, the end of the end electrode can be isolated from the end of the inner electrode by the first additional electrode, thereby reducing the degree of electric field concentration and reducing the risk of breakdown and burnout. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a multilayer ceramic capacitor in the prior art.

[0018] Figure 2 This is a structural schematic diagram of an embodiment of the present invention.

[0019] Figure 3 This is a sectional view from one side of an embodiment of the present invention.

[0020] Figure 4 This is a top sectional view of Embodiment 1 of the present invention.

[0021] Figure 5 This is a top sectional view of Embodiment 2 of the present invention.

[0022] Figure 6 This is a top sectional view of Embodiment 3 of the present invention.

[0023] Figure 7 This is a side view of the fabrication process of the multilayer ceramic capacitor in Embodiment 1 of the present invention.

[0024] Figure 8 This is a top view of the fabrication process of the multilayer ceramic capacitor in Embodiment 1 of the present invention.

[0025] In the figure, 1 is the ceramic body; 2 is the terminal electrode; 3 is the protective electrode; 11 is the inner electrode; 12 is the dielectric layer; 13 is the first auxiliary electrode; 14 is the second auxiliary electrode; 15 is the upper surface of the ceramic body; 16 is the lower surface of the ceramic body; 17 is the end face of the ceramic body; 18 is the side face of the ceramic body; 19 is the third auxiliary electrode; 21 is the bottom terminal; 22 is the middle terminal; and 23 is the surface terminal. Detailed Implementation

[0026] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0027] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0030] Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] Example 1

[0032] Please refer to Figures 2-4 A preferred embodiment of the present invention provides a multilayer ceramic capacitor, comprising a ceramic body 1 and end electrodes 2 disposed on two end faces 17 of the ceramic body 1. The end electrodes 2 extend to two side faces 18 of the ceramic body 1, and the ends of the two end electrodes 2 are disposed opposite each other with a distance between them. The ceramic body 1 includes inner electrodes 11, a dielectric layer 12, and a first additional electrode 13. The inner electrodes 11 are arranged in parallel, and a dielectric layer 12 is disposed between two adjacent inner electrodes 11. One end of an inner electrode 11 extends to and connects to one of the end electrodes 2. The other end of an inner electrode 11 is disposed between the end of the other end electrode 2 and the end of the other end electrode 2, and the first additional electrode 13 is disposed at a corner of the dielectric layer 12. Here, "corner" refers to one or more corners of the dielectric layer 12, all of which are provided with the first additional electrode 13.

[0033] The multilayer ceramic capacitor of the present invention, through such a structure, can isolate the end of the terminal electrode 2 from the end of the inner electrode 11 by means of the first additional electrode 13, thereby reducing the degree of electric field concentration, reducing the risk of breakdown and burnout, and ensuring the voltage withstand performance of the multilayer ceramic capacitor.

[0034] Specifically, the ceramic body 1 may have multiple inner electrodes 11 and dielectric layers 12, and at least one first auxiliary electrode 13, which is spaced a certain distance from the inner electrode 11. The connection between the first auxiliary electrode 13 and the terminal electrode 2 is also located on the end face 17 of the ceramic body 1. Multiple dielectric layers 12 are stacked to form a cuboid ceramic body 1 with six faces. The length of the ceramic body 1 ranges from 0.4 mm to 5.6 mm, the width ranges from 0.2 mm to 5.0 mm, and the thickness ranges from 0.2 mm to 2.5 mm.

[0035] The inner electrode 11 is preferably a rectangular thin layer with a thickness ranging from 1 μm to 3 μm. Within this thickness range, a large volume utilization rate and ease of production can be achieved. The number of inner electrodes 11 is preferably greater than 40. The inner electrodes 11 are spaced at a certain distance from the upper surface 15, lower surface 16, and two side surfaces 18 of the ceramic body 1, which can prevent moisture and mechanical damage.

[0036] In this embodiment, please refer to Figure 4 The first auxiliary electrode 13 has a curved profile facing the inner electrode 11 at the same height. The specific shape of the curve is not limited; the curve only needs to be smooth to avoid sharp corners. In this embodiment, the curve is parabolic. The corners of the first auxiliary electrode 13 are rounded. This reduces the charge concentration on the inner electrode 11 and improves the voltage withstand performance of the multilayer ceramic capacitor.

[0037] The ceramic body 1 also includes a second additional electrode 14. The second additional electrode 14 is disposed between two adjacent dielectric layers 12 between two adjacent inner electrodes 11. The second additional electrode 14 is also disposed between two upper and lower first additional electrodes 13. The second additional electrode 14 is also connected to the end electrode 2, and the connection point is located on the side surface 18 of the ceramic body 1. Preferably, the number of second additional electrodes 14 is 30 or more, which is greater than the number of inner electrodes 11. The second additional electrode 14 can improve the effect of reducing electric field concentration. The connection point between the second additional electrode 14 and the end electrode 2 is also located on the end face 17 of the ceramic body 1.

[0038] In addition, a third auxiliary electrode 19 may be provided. The third auxiliary electrode 19 is disposed between the upper surface of the ceramic body and the first auxiliary electrode 13, and may be configured with the same shape as the first auxiliary electrode 13, and may be disposed directly above the first auxiliary electrode 13.

[0039] In this embodiment, the first auxiliary electrode 13, the second auxiliary electrode 14, and the third auxiliary electrode 19 are identical in size and shape. Preferably, the thickness of the first auxiliary electrode 13, the second auxiliary electrode 14, and the third auxiliary electrode 19 is less than 5 μm.

[0040] The multilayer ceramic capacitor of the present invention further includes protective electrodes 3, which are disposed at both ends of the upper surface 15 and / or both ends of the lower surface 16 of the ceramic body 1. The edge of the protective electrode 3 away from the end of the ceramic body 1 is straight, and the end electrode 2 covers the protective electrode 3. The protective electrode 3 may be disposed only on the upper surface 15 of the ceramic body 1, only on the lower surface 16 of the ceramic body 1, or on both the upper surface 15 and the lower surface 16 of the ceramic body 1. In this embodiment, the protective electrodes 3 are rectangular, spaced apart from each other, and the protective electrodes 3 at both ends of the ceramic body 1 are insulated from each other along the length direction, and the protective electrodes 3 are symmetrically arranged on the ceramic body 1. In other embodiments, the protective electrodes 3 may also be other shapes, such as trapezoidal, triangular, etc. The thickness of the protective electrode 3 is greater than 5 μm, preferably 5 μm-10 μm. If the thickness of the protective electrode 3 is less than 5 μm, it will be easily worn away during the grinding of the ceramic body 1 during the preparation process; if the thickness of the protective electrode 3 is greater than 10 μm, it will result in an excessively thick multilayer ceramic capacitor. The materials of the protective electrode 3, the inner electrode 11, the first additional electrode 13, the second additional electrode 14, and the third additional electrode 19 are nickel or copper. Preferably, the materials of the protective electrode 3, the inner electrode 11, the first additional electrode 13, the second additional electrode 14, and the third additional electrode 19 are the same.

[0041] In addition, the terminal electrode 2 includes a bottom terminal 21, an intermediate terminal 22 and a surface terminal 23 arranged sequentially from the inside to the outside. The bottom terminal 21 located on the upper surface 15 and the lower surface 16 of the ceramic body 1 is disposed on the outer surface of the protective electrode 3. The intermediate terminal 22 located on the upper surface 15 and the lower surface 16 of the ceramic body 1 is disposed on the bottom terminal 21 and extends to the protective electrode 3. The intermediate terminal 22 completely covers the bottom terminal 21 and the protective electrode 3. The surface terminal 23 located on the upper surface 15 and the lower surface 16 of the ceramic body 1 is disposed on the intermediate terminal 22 and completely covers the intermediate terminal 22. The first additional electrode 13 is located between the end of the surface terminal and the end of the inner electrode 11.

[0042] The end electrodes 2 are spaced apart from each other and insulated from each other. The end electrodes 2 also extend to the upper surface 15 and the lower surface 16 of the ceramic body 1. In this embodiment, the end electrodes 2 completely cover the end face 17 of the ceramic body 1 and partially cover the upper surface 15, the lower surface 16 and the other two side surfaces 18.

[0043] The bottom terminal 21 is made of copper and has a thickness of 20μm-60μm. If the thickness is less than 20μm, it is difficult to fabricate the bottom terminal 21. If the thickness is greater than 60μm, it will result in the multilayer ceramic capacitor being too thick.

[0044] The intermediate terminal 22 is made of nickel and is formed by electroplating, with a thickness of 2μm-5μm. Within this thickness range, a continuous and uniform nickel layer can be obtained, ensuring the good solderability of the multilayer ceramic capacitor.

[0045] The surface terminal 23 is made of tin and is formed by electroplating, with a thickness of 5μm-10μm. Within this thickness range, a continuous and uniform tin layer can be obtained, ensuring good solderability of the multilayer ceramic capacitor.

[0046] Since both the intermediate terminal 22 and the surface terminal 23 are formed by electroplating, the distance between the end of the intermediate terminal 22 furthest from its adjacent end face 17 (i.e., the end of the intermediate terminal 22) and end face 17 is equal to the distance between the end of the first auxiliary electrode 13 furthest from its adjacent end face 17 (i.e., the end of the first auxiliary electrode 13) and end face 17. The distance between the end of the surface terminal 23 furthest from its adjacent end face 17 (i.e., the end of the surface terminal 23) and end face 17 is 5μm-10μm greater than the distance between the end of the first auxiliary electrode 13 furthest from its adjacent end face 17 (i.e., the end of the first auxiliary electrode 13) and end face 17. Therefore, the end of the surface terminal 23 will form a sharp corner.

[0047] In this embodiment, the distance between the end of the first auxiliary electrode 13 furthest from the end face 17 (i.e., the end of the first auxiliary electrode 13) and the end face 17 is denoted as d1. The distance between the end of the bottom terminal 21 furthest from the end face 17 (i.e., the end of the bottom terminal 21) and the end face 17 is denoted as d2. The distance between the end of the inner electrode 11 and the end face 17 not connected to it is denoted as d3. The distance between the end of the protective electrode 3 furthest from the end face 17 (i.e., the end of the protective electrode 3) and the end face 17 is denoted as d4.

[0048] In this embodiment, d1 > d2 and d1 > d3, such that the sharp corner formed at the end of the surface terminal 23 is blocked by the first additional electrode 13 from the end of the inner electrode 11, thereby reducing the degree of electric field concentration.

[0049] Preferably, d1 is 10%-25% of the length of the multilayer ceramic capacitor. If d1 is less than 10%, the multilayer ceramic capacitor is not easy to solder, while if d1 is greater than 25%, the distance between the two terminal electrodes 2 is small, which can easily lead to arcing.

[0050] Preferably, d3 is 5%-15% of the length of the multilayer ceramic capacitor. If d3 is less than 5%, the insufficient process allowance will easily lead to short circuit between the internal electrode 11 and the unconnected terminal electrode 2. If d3 is greater than 15%, it will be detrimental to obtaining a higher capacitance for the multilayer ceramic capacitor.

[0051] Preferably, d4 > d2. This configuration ensures that the ends of the intermediate terminal 22 and the surface terminal 23 form straight edge profiles, meaning that the intersection lines between the ends of the intermediate terminal 22 and the surface terminal 23 and the upper surface 15 and lower surface 16 are straight segments. This effectively prevents surface discharge caused by concentrated surface electric fields. Furthermore, by controlling the value of d4, sufficient spacing can be maintained between the surface terminals 23 of the two end electrodes 2, preventing surface discharge arcing of the ceramic body 1.

[0052] In this embodiment, the intermediate terminal 22 and the surface terminal 23 are formed by electroplating, with d1 > d2. The ends of the intermediate terminal 22 located on the side 18 of the ceramic body 1 form flat edges with the ends of the first auxiliary electrode 13 and the second auxiliary electrode 14, respectively. As a result, the ends of the surface terminal 23 are also flat, and the edges of the surface terminals 23 at both ends are parallel to each other. By controlling the size of d1, sufficient spacing can be maintained between the surface terminals 23 between the two end electrodes 2 to prevent surface discharge arcing of the ceramic body 1.

[0053] In this embodiment, d4 = d1.

[0054] This embodiment also provides a method for preparing a multilayer ceramic capacitor, including the following steps:

[0055] Step 1: Prepare ceramic membranes using ceramic slurry.

[0056] Specifically, ceramic powder, binder, and organic solvent are mixed and dispersed evenly using ball milling or sand milling to obtain a ceramic slurry, which is then cast into a ceramic film. The ceramic powder can be barium titanate, calcium zirconate, calcium titanate, or other ceramic materials commonly used in multilayer ceramic capacitors.

[0057] Step 2: Form the pattern of the inner electrode 11 and the pattern of the additional electrode (i.e., the first additional electrode 13, the second additional electrode 14 or the third additional electrode 19) on the ceramic film.

[0058] Metal paste is applied to a ceramic film using screen printing. After the metal paste is dried, an inner electrode 11 pattern and an additional electrode pattern are formed on the ceramic film.

[0059] Additional electrode patterns can be formed simultaneously on each ceramic film with an inner electrode 11 pattern, so that the additional electrodes and the inner electrodes 11 are stacked on the same dielectric layer 12 to achieve a sufficient reduction in electric field concentration. When the number of additional electrodes is greater than the number of inner electrodes 11, additional electrode patterns can also be formed separately on the ceramic film in step one.

[0060] The metal in the metal paste is preferably nickel or copper. Preferably, the same metal paste is used to form the inner electrode 11 pattern and the additional electrode pattern to maintain consistent sintering characteristics and ensure good compactness of the ceramic body 1.

[0061] Step 3: Stack multiple ceramic films with internal electrode 11 patterns and multiple ceramic films with additional electrode patterns in a certain order to obtain a ceramic substrate.

[0062] Multiple ceramic films with internal electrode 11 patterns are stacked, and adjacent ceramic films with internal electrode 11 patterns are staggered at a predetermined distance during stacking to facilitate the exposure of the internal electrodes 11 on the end face 17 in subsequent processes. At least one ceramic film with an additional electrode pattern is interleaved and stacked between adjacent ceramic films with internal electrode 11 patterns. By setting the thickness of the ceramic films, the distance between adjacent additional electrode patterns in the stacking direction can be controlled, thereby controlling the distance between adjacent additional electrodes in the thickness direction of the multilayer ceramic capacitor.

[0063] In the stacking direction, a portion of the ceramic films with additional electrode patterns are positioned on the outermost side of the ceramic substrate. This results in a longer distribution range of the additional electrodes compared to the distribution range of the inner electrodes 11 in the thickness direction of the multilayer ceramic capacitor, thereby improving the effect of reducing electric field concentration. In other embodiments, multiple ceramic films obtained in step one may be positioned on the outermost side of the ceramic substrate; or a portion of the ceramic films with additional electrode patterns may be stacked on both sides of the ceramic film with the inner electrode 11 pattern, and then the multiple ceramic films obtained in step one may be used as the outermost side of the ceramic substrate; or multiple ceramic films obtained in step one may be stacked on both sides of the ceramic film with the inner electrode 11 pattern, and then a portion of the ceramic films with additional electrode patterns may be used as the outermost side of the ceramic substrate; or other interleaving combinations may be used.

[0064] Step 4: Form the protective electrode 3 pattern on both sides of the ceramic substrate.

[0065] Metal paste is applied to both sides of a ceramic substrate using screen printing. After drying, the metal paste forms a protective electrode 3 pattern attached to the ceramic substrate. The protective electrode 3 pattern can be made to a thickness of 5μm-10μm through repeated printing.

[0066] The metal in the metal paste is preferably nickel or copper. Preferably, the same metal paste is used to form the protective electrode 3 pattern and the inner electrode 11 pattern, so as to facilitate simultaneous sintering.

[0067] Before forming the pattern of the protective electrode 3, the ceramic substrate can be pressed tightly using isostatic pressing; alternatively, the ceramic substrate can be pressed tightly using isostatic pressing after forming the pattern of the protective electrode 3. In other embodiments, the metal paste can be coated onto the ceramic film obtained in step one to form the pattern of the protective electrode 3, and then the ceramic film with the pattern of the protective electrode 3 can be stacked on both sides of the ceramic substrate and pressed.

[0068] Step 5: Cut the ceramic substrate to obtain multiple ceramic green sheets.

[0069] The ceramic substrate is cut longitudinally and transversely according to the required length and width dimensions to obtain multiple rectangular ceramic green sheets, and the edges of the inner electrode 11 and the additional electrode are exposed on the cut surface.

[0070] Specifically, on each ceramic green sheet, the inner electrode 11 is exposed on two cut surfaces corresponding to the end face 17, the auxiliary electrode is exposed on four cut surfaces corresponding to the end face 17 and the side face 18, and the protective electrode 3 is attached to two upper and lower surfaces 16 in addition to the four cut surfaces.

[0071] Step 6: Sinter the ceramic green sheet to obtain ceramic body 1.

[0072] The ceramic green sheet is heated to 950℃-1300℃ and sintered to obtain ceramic body 1. After sintering, the pattern of the inner electrode 11 becomes the inner electrode 11, the pattern of the auxiliary electrode becomes the auxiliary electrode, the pattern of the protective electrode 3 becomes the protective electrode 3, and the ceramic film becomes the dielectric layer 12.

[0073] If necessary, the ceramic green sheets can be heat-treated before sintering to remove organic components and improve the mechanical and dielectric properties of the ceramic body 1.

[0074] Step 7: Immerse both ends of the ceramic body 1 in copper paste, and then sinter the copper paste to form the bottom terminal 21.

[0075] Please refer to Figure 7 and Figure 8 The two ends of the ceramic body 1 are impregnated with copper paste, and then the copper paste is heated to 950℃-1300℃ for sintering. After sintering, the copper paste forms the bottom terminal 21. By controlling the impregnation depth of the copper paste, d2 < d1 and d2 < d4.

[0076] Step 8: Using an electroplating method, intermediate terminals 22 and surface terminals 23 are successively formed on the bottom terminal 21 to obtain the multilayer ceramic capacitor of the present invention.

[0077] By using an electroplating method, nickel is first electroplated on the bottom terminal 21 to form the intermediate terminal 22, and then tin is electroplated on the intermediate terminal 22 to form the surface terminal 23, thus obtaining a multilayer ceramic capacitor.

[0078] During nickel plating, since both the protective electrode 3 and the auxiliary electrode are metals, the nickel plating layer also precipitates and grows on the exposed portion of the auxiliary electrode on the side 18 of the protective electrode 3 and the ceramic body 1. Between the adjacent auxiliary electrodes stacked on top of each other, the nickel plating layer gradually connects with each other, eventually forming a continuous and integral nickel plating layer with straight edge lines, which not only completely covers the intermediate terminal 22, but also completely covers the exposed portion of the protective electrode 3 and the auxiliary electrode.

[0079] When the distance between adjacent auxiliary electrodes in the thickness direction of the multilayer ceramic capacitor is set to 10 μm or less, more preferably 5 μm or less, it facilitates the growth and connection of the nickel plating layer between the exposed portions of the adjacent auxiliary electrodes during electroplating, and makes it easy to form a continuous nickel plating layer.

[0080] If necessary, after the sintering process in step six, the ceramic body 1 can be subjected to appropriate tumbling grinding to fully expose the additional electrode on the side surface 18 and end surface 17 of the ceramic body 1, which makes it easier for the nickel plating layer to precipitate and grow during nickel electroplating. Setting the thickness of the protective electrode 3 to 5μm-10μm ensures that the protective electrode 3 can maintain its original complete pattern even after grinding.

[0081] Example 2

[0082] The multilayer ceramic capacitor provided in Example 2 differs from that in Example 1 in that, please refer to... Figure 5 The end of the first auxiliary electrode 13 is semi-circular and located inside the ceramic body 1, not on its surface. The distance between the end of the first auxiliary electrode 13 furthest from its adjacent end face 17 (i.e., the end of the first auxiliary electrode 13 in this embodiment) and the end face 17 is denoted as d5. d5 > d1, and preferably, d5 is at least 10 μm larger than d1. With this structure, the first auxiliary electrode 13 can provide better barrier effect, reducing the electric field concentration between the end electrode 2 and the inner electrode 11.

[0083] Example 3

[0084] The multilayer ceramic capacitor provided in Example 3 differs from that in Example 1 in that, please refer to... Figure 6 The first auxiliary electrode 13 is not connected to either of the two end faces 17, but extends only to the side face 18 of the ceramic body 1. In this embodiment, the two ends of the first auxiliary electrode 13 are arc-shaped.

[0085] In summary, the present invention provides a multilayer ceramic capacitor that uses a first additional electrode 13 to block the end of the terminal electrode 2 from the end of the inner electrode 11, thereby reducing the degree of electric field concentration, reducing the risk of breakdown and burnout, and ensuring the voltage withstand performance of the multilayer ceramic capacitor.

[0086] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A multilayer ceramic capacitor, characterized in that, The device includes a ceramic body and end electrodes disposed on both ends of the ceramic body. The end electrodes extend to two sides of the ceramic body, and the ends of the two end electrodes are disposed opposite each other with a distance between them. The ceramic body includes an inner electrode, a dielectric layer, and a first additional electrode. The inner electrodes are disposed in parallel, and the dielectric layer is disposed between two adjacent inner electrodes. One end of the inner electrode extends to one of the end electrodes and is connected to the end electrode. The other end of the inner electrode is disposed between the end of the other end electrode and the end of the other end electrode, and the first additional electrode is disposed at the corner of the dielectric layer. The end electrode also extends to the upper and lower surfaces of the ceramic body; The ceramic body further includes a second additional electrode, which is disposed between two adjacent dielectric layers between two adjacent inner electrodes. The second additional electrode is also disposed between two upper and lower first additional electrodes, and is connected to the end electrode with the connection point located on the side of the ceramic body. It also includes protective electrodes, which are disposed at both ends of the upper surface and / or both ends of the lower surface of the ceramic body. The edge of the protective electrode away from the end of the ceramic body is straight, and the end electrode covers the protective electrode. The terminal electrode includes a bottom terminal, an intermediate terminal, and a surface terminal arranged sequentially from the inside to the outside. The bottom terminal located on the upper surface and the lower surface of the ceramic body is disposed on the outer surface of the protective electrode. The intermediate terminal located on the upper surface and the lower surface of the ceramic body is disposed on the bottom terminal and extends to the protective electrode. The intermediate terminal completely covers the bottom terminal and the protective electrode. The surface terminal located on the upper surface and the lower surface of the ceramic body is disposed on the intermediate terminal and completely covers the intermediate terminal. The first additional electrode is located between the end of the surface terminal and the end of the inner electrode.

2. The multilayer ceramic capacitor according to claim 1, characterized in that, The first additional electrode is configured with a curved profile on the side facing the inner electrode at the same height.

3. The multilayer ceramic capacitor according to claim 1, characterized in that, The connection between the first additional electrode and the end electrode is also located on the end face of the ceramic body.

4. The multilayer ceramic capacitor according to claim 1, characterized in that, The corners of the first additional electrode are rounded off.

5. The multilayer ceramic capacitor according to claim 1, characterized in that, The first and second additional electrodes are the same size and shape.

6. The multilayer ceramic capacitor according to claim 1, characterized in that, The connection between the second additional electrode and the end electrode is also located on the end face of the ceramic body.

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