A multilayer ceramic capacitor

Abstract

The application relates to the technical field of capacitors, and discloses a multilayer ceramic capacitor which comprises a ceramic body and end electrodes arranged on the two end faces of the ceramic body, the end electrodes extend to the upper surface and the lower surface of the ceramic body, the ends of the two end electrodes are oppositely arranged and have a distance between each other, and the end of each end electrode is arranged in a circular arc shape towards one side of the ceramic body. The multilayer ceramic capacitor has the end of the end electrode arranged in a circular arc shape towards one side of the ceramic body, and the surface of the end of the end electrode towards the inside of the ceramic body is a curved surface, so that the concentration degree of the electric field is reduced, the withstand voltage performance of the multilayer ceramic capacitor is improved, and the risk of being broken down and burnt is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of capacitor, in particular to a multilayer ceramic capacitor. BACKGROUND

[0002] At present, referring to Figure 1 , a sectional view of the prior art multilayer ceramic capacitor, two end faces 15' of a ceramic body are provided with end electrodes 2', and the end electrodes 2' also extend to the upper and lower surfaces of the ceramic body, the end part of the end electrodes 2' extending to the upper and lower surfaces of the ceramic body is marked as the end of the end electrode 2', the ceramic body includes a plurality of dielectric layers 11' stacked along the thickness direction of the ceramic body and an internal electrode 12' provided between adjacent two dielectric layers 11', the internal electrode 12' includes a first internal electrode 121' and a second internal electrode 122' connected with the two end electrodes 2' respectively, and the other end of the first internal electrode 121' and the other end of the second internal electrode 122' are marked as the end of the first internal electrode 121' and the end of the second internal electrode 122' respectively, both have a distance from the end face 15' of the ceramic body pointed to, and the first internal electrode 121' and the second internal electrode 122' are alternately arranged.

[0003] In the prior art, the end electrodes are formed by the method that the ceramic body is immersed in electrode slurry. The end of the end electrode extending to the upper and lower surfaces of the ceramic body will form a sharp corner shape due to the rheological behavior of the electrode slurry affected by gravity, and the sharp corner shape is directed towards the direction of the internal electrode, and also diagonally corresponds to the end of the first internal electrode or the end of the second internal electrode, thus causing the electric field concentration to be intensified, and the multilayer ceramic capacitor has the risk of being broken down and burned out. SUMMARY

[0004] The purpose of the present application is to provide a multilayer ceramic capacitor which can improve the problem of electric field concentration and reduce the risk of being broken down and burned out.

[0005] In order to achieve the above purpose, the present application provides a multilayer ceramic capacitor, which includes a ceramic body and end electrodes provided on two end faces of the ceramic body, the end electrodes extend to the upper and lower surfaces of the ceramic body, and the ends of the two end electrodes are oppositely arranged and have a distance therebetween, and the end of the end electrode is arranged as a circular arc towards one side of the ceramic body.

[0006] Preferably, the part of the end of the end electrode arranged as a circular arc is marked as a transition part, and the transition part extends to the side of the end of the end electrode away from the ceramic body.

[0007] Preferably, the included angle α between the transition part and the side of the end of the end electrode away from the ceramic body is 60°-90°.

[0008] Preferably, the ceramic body further comprises dielectric layers arranged in layers and inner electrodes arranged between two adjacent dielectric layers.

[0009] Preferably, the distance between the end of the end electrode on the upper surface or the lower surface of the ceramic body and the end surface of the ceramic body to which the inner electrode points is denoted as d1, and the distance between the end of the inner electrode and the end surface of the ceramic body to which the inner electrode points is denoted as d2, wherein d1 is greater than d2.

[0010] Preferably, the edge of the end of the inner electrode is arranged in a circular arc transition.

[0011] Preferably, the inner electrode comprises a first inner electrode and a second inner electrode, one end of the first inner electrode is connected to one of the end electrodes, and the end of the first inner electrode is spaced apart from the other end electrode, one end of the second inner electrode is connected to the end electrode not connected to the first inner electrode, and the end of the second inner electrode is spaced apart from the end electrode connected to the first inner electrode, and the first inner electrode and the second inner electrode are arranged alternately.

[0012] Preferably, the inner electrode comprises a first inner electrode, a second inner electrode and a third inner electrode, one end of the first inner electrode and one end of the second inner electrode are connected to two end electrodes respectively, the first inner electrode and the second inner electrode are arranged opposite to each other, both ends of the third inner electrode are spaced apart from two end electrodes respectively, and the third inner electrode and the first inner electrode are arranged alternately.

[0013] Preferably, the third inner electrode is arranged between the dielectric layer on the upper surface of the ceramic body and the dielectric layer adjacent thereto, and between the dielectric layer on the lower surface of the ceramic body and the dielectric layer adjacent thereto.

[0014] Preferably, the end electrode further extends to both sides of the ceramic body.

[0015] The present application provides a multilayer ceramic capacitor, which has the beneficial effects compared with the prior art in that:

[0016] The multilayer ceramic capacitor of the present application comprises a ceramic body and end electrodes arranged on both end surfaces of the ceramic body, the end electrodes extend to the upper surface and the lower surface of the ceramic body, the ends of the two end electrodes are arranged opposite to each other and spaced apart from each other, and the end of the end electrode towards the side of the ceramic body is arranged in a circular arc shape. By arranging the end of the end electrode towards the side of the ceramic body in a circular arc shape, the surface of the end of the end electrode towards the inside of the ceramic body is curved, which reduces the concentration degree of the electric field, improves the withstand voltage performance of the multilayer ceramic capacitor, and reduces the risk of breakdown and burning. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0019] Figure 3 is a sectional view of the embodiment one of the present application.

[0020] Figure 4 is a sectional view of the embodiment two of the present application.

[0021] Figure 5 is a sectional view of the embodiment three of the present application.

[0022] In the drawings, 1, ceramic body; 2, end electrode; 11, dielectric layer; 12, inner electrode; 13, upper surface of the ceramic body; 14, side surface of the ceramic body; 15, end surface of the ceramic body; 121, first inner electrode; 122, second inner electrode; 123, third inner electrode; 21, transition portion. DETAILED DESCRIPTION

[0023] The specific embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0024] In the description of the present application, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0025] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be broadly understood, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] In addition, in the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0027] For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] Embodiment one

[0029] Please refer to Figure 2 and Figure 3 A multilayer ceramic capacitor according to an embodiment of the present application comprises a ceramic body 1 and end electrodes 2 arranged on the end faces 15 of the ceramic body 1, the end electrodes 2 extending to the upper surface 13 and the lower surface of the ceramic body 1, and the ends of the two end electrodes 2 being oppositely arranged and having a distance therebetween, and the end of the end electrode 2 being arranged in a circular arc shape towards one side of the ceramic body 1. By arranging the end of the end electrode 2 in a circular arc shape towards one side of the ceramic body 1, the surface of the end of the end electrode 2 towards the inside of the ceramic body 1 is curved, which reduces the degree of concentration of the electric field, improves the withstand voltage performance of the multilayer ceramic capacitor, and reduces the risk of breakdown and burning. Specifically, the length of the multilayer ceramic capacitor ranges from 1.0 mm to 5.6 mm, the width ranges from 0.5 mm to 5.0 mm, and the thickness ranges from 0.5 mm to 2.5 mm.

[0030] The part of the end of the end electrode 2 arranged in a circular arc shape is referred to as a transition portion 21, and the transition portion 21 extends to the side of the end of the end electrode 2 away from the ceramic body 1. The end electrodes 2 are spaced apart from and insulated from each other. In a specific production embodiment, recesses can be arranged on the ceramic body 1 corresponding to the positions of the end electrodes 2, so as to form the transition portion 21 in a circular arc shape.

[0031] The included angle α between the transition portion 21 and the side 14 of the end of the end electrode 2 away from the ceramic body 1 is 60°-90°. Preferably, it is 90°. If the included angle α is greater than 90°, it is difficult to form the transition portion 21 in a circular arc shape; if the included angle α is less than 60°, the effect of reducing the degree of concentration of the electric field is poor.

[0032] In addition, the height of the end face 15 of the ceramic body 1 is more than 80%, and preferably more than 90%, of the thickness of the multilayer ceramic capacitor. If the height of the end face 15 of the ceramic body 1 is small, the space for accommodating the internal electrodes 12 is reduced, which is not conducive to obtaining high capacitance, and positioning is difficult in some production processes; if the height is large, it is also not conducive to forming the transition portion 21 in a circular arc shape.

[0033] The ceramic body 1 further comprises dielectric layers 11 arranged in layers and internal electrodes 12 arranged between adjacent two dielectric layers. In order to obtain a larger volume utilization rate and facilitate production, the shape of the internal electrodes 12 is preferably a rectangular thin layer. The thickness of the internal electrodes 12 is preferably 1 μm-3 μm. The number is preferably more than 40.

[0034] The distance between the end electrode 2 and the end surface 15 of the ceramic body 1 to which the inner electrode 12 points is denoted as d2, and d1 is greater than d2. Preferably, d1 is 10%-25% of the length of the multilayer ceramic capacitor. If d1 is too small, it is inconvenient to solder the multilayer ceramic capacitor; if d1 is too large, the length of the exposed surface of the ceramic body 1 is small, which is not conducive to adsorbing the multilayer ceramic capacitor during production. The length of the exposed surface of the ceramic body 1 is more than 50% of the length of the multilayer ceramic capacitor, which is conducive to adsorbing the multilayer ceramic capacitor, improves the mounting efficiency, and is convenient for positioning, thereby improving the production qualification rate. Preferably, d2 is 5%-15% of the length of the multilayer ceramic capacitor. If d2 is too small, the process allowance is insufficient, which easily leads to short-circuiting between the inner electrode 12 and the end electrode 2 that is not connected thereto, and if d2 is too large, it is not easy to obtain a high capacitance.

[0035] The edge of the end of the inner electrode 12 is arranged in a circular arc transition. Through such a structure, the degree of charge concentration of the inner electrode 12 can also be reduced, and the withstand voltage performance of the multilayer ceramic capacitor is further improved.

[0036] In order to prevent moisture and mechanical damage, the inner electrode 12 is spaced apart from the upper and lower surfaces and the two side surfaces 14 of the ceramic body 1 by a certain distance. The distance between the inner electrode 12 and the upper and lower surfaces is greater than 0.05 mm, so as to avoid short-circuiting between the inner electrode 12 and the end electrode 2.

[0037] Specifically, the inner electrode 12 includes a first inner electrode 121 and a second inner electrode 122, one end of the first inner electrode 121 is connected to one end electrode 2, and the end of the first inner electrode 121 is spaced apart from the other end electrode 2, one end of the second inner electrode 122 is connected to the end electrode 2 that is not connected to the first inner electrode 121, and the end of the second inner electrode 122 is spaced apart from the end electrode 2 connected to the first inner electrode 121, and the first inner electrode 121 and the second inner electrode 122 are arranged alternately. In this way, the first inner electrode 121 and the end electrode 2 not connected thereto are insulated, and the second inner electrode 122 and the end electrode 2 not connected thereto are also insulated. Moreover, the above-mentioned distances are all less than half the length of the first inner electrode 121 and the second inner electrode 122, so as to ensure that the first inner electrode 121 and the second inner electrode 122 generate opposite areas and generate capacitance, and therefore the more the number of the first inner electrode 121 and the second inner electrode 122 arranged alternately, the higher the capacitance. The ends of the inner electrode 12 are staggered in the length direction of the multilayer ceramic capacitor, so as to reduce the degree of electric field concentration.

[0038] Embodiment Two

[0039] The multilayer ceramic capacitor provided in Embodiment Two is different from that in Embodiment One in that Figure 4, the end electrode 2 also extends to the two side surfaces 14 of the ceramic body 1. The end of the end electrode 2 on the side surface 14 of the ceramic body 1 is shaped the same as the end of the end electrode 2 on the upper and lower surfaces of the ceramic body 1 in the first embodiment, and a recess corresponding to the end of the end electrode 2 is also provided on the side surface 14 of the ceramic body 1.

[0040] The second embodiment can reduce the degree of electric field concentration of the end electrode 2 on the side surface 14 of the ceramic body 1 and improve the voltage endurance of the multilayer ceramic capacitor through the structure.

[0041] The third embodiment

[0042] The multilayer ceramic capacitor provided by the third embodiment is different from the first embodiment in that Figure 5 The inner electrode 12 includes a first inner electrode 121, a second inner electrode 122, and a third inner electrode 123, one end of the first inner electrode 121 and one end of the second inner electrode 122 are connected to the two end electrodes 2 respectively, the first inner electrode 121 is arranged opposite to the second inner electrode 122, the two ends of the third inner electrode 123 are both away from the two end electrodes 2, and the third inner electrode 123 is arranged alternately with the first inner electrode 121. In this way, the third inner electrode 123 is a floating electrode and is not connected to the end electrode 2. The first inner electrode 121 and the second inner electrode 122 respectively have opposite areas with the third inner electrode 123, forming a structure in which capacitors are connected in series, achieving voltage distribution, and improving the voltage endurance of the multilayer ceramic capacitor.

[0043] The third inner electrode 123 is arranged between the dielectric layer on the upper surface 13 of the ceramic body 1 and the dielectric layer adjacent to it and the dielectric layer on the lower surface of the ceramic body 1. The two ends of the third inner electrode 123 form an electric field concentration area, but since the end of the end electrode 2 facing the inside of the ceramic body 1 is a curved surface, the degree of electric field concentration is reduced, the voltage endurance of the multilayer ceramic capacitor is improved, and the risk of breakdown and burning is reduced.

[0044] In summary, the embodiments of the present application provide a multilayer ceramic capacitor, which reduces the degree of electric field concentration by arranging the end of the end electrode 2 to be arc-shaped on one side of the ceramic body 1 and the surface of the end of the end electrode 2 facing the inside of the ceramic body 1 to be curved, improves the voltage endurance of the multilayer ceramic capacitor, and reduces the risk of breakdown and burning.

[0045] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and replacements without departing from the technical principles of the present application, and these improvements and replacements should also be considered within the protection scope of the present application.

Claims

1. A multilayer ceramic capacitor, characterized by, The ceramic body and the end electrodes arranged on both end surfaces of the ceramic body, the end electrodes extending to the upper surface and the lower surface of the ceramic body, and the tips of the two end electrodes oppositely arranged and having a distance between them, the tips of the end electrodes arranged in a circular arc shape towards one side of the ceramic body; The part where the tips of the end electrodes are arranged in a circular arc shape is referred to as a transition part, and the transition part extends to the side of the tips of the end electrodes away from the ceramic body; The included angle α between the transition part and the side of the tips of the end electrodes away from the ceramic body is 60°-90°; The ceramic body is provided with a recess corresponding to the transition part.

2. The multilayer ceramic capacitor of claim 1, wherein, The ceramic body further comprises dielectric layers arranged in layers and inner electrodes arranged between adjacent dielectric layers.

3. The multilayer ceramic capacitor of claim 2, wherein, The distance of the part of the end electrode on the upper surface or the lower surface of the ceramic body in the length direction of the dielectric layer is referred to as d1, and the distance between the inner electrode and the end surface of the ceramic body pointed by the inner electrode is referred to as d2, d1 is greater than d2.

4. The multilayer ceramic capacitor of claim 2, wherein, The edge of the tip of the inner electrode is arranged in a circular arc transition.

5. The multilayer ceramic capacitor of claim 2, wherein, The inner electrode comprises a first inner electrode and a second inner electrode, one end of the first inner electrode is connected with one of the end electrodes, and the tip of the first inner electrode has a distance from the other end electrode, one end of the second inner electrode is connected with the end electrode not connected with the first inner electrode, and the tip of the second inner electrode has a distance from the end electrode connected with the first inner electrode, and the first inner electrode and the second inner electrode are arranged alternately.

6. The multilayer ceramic capacitor of claim 2, wherein, The inner electrode comprises a first inner electrode, a second inner electrode and a third inner electrode, one end of the first inner electrode and one end of the second inner electrode are respectively connected with two end electrodes, the first inner electrode and the second inner electrode are oppositely arranged, both ends of the third inner electrode have a distance from two end electrodes, and the third inner electrode and the first inner electrode are arranged alternately.

7. The multilayer ceramic capacitor of claim 6, wherein, The third inner electrode is arranged between the dielectric layer on the upper surface of the ceramic body and the dielectric layer adjacent thereto and the dielectric layer on the lower surface of the ceramic body and the dielectric layer adjacent thereto.

8. The multilayer ceramic capacitor of claim 1, wherein, The end electrode further extends to both sides of the ceramic body.

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