MLCC capacitor of fusion terminal electrode and preparation method of MLCC capacitor

Abstract

The invention provides an MLCC capacitor fused with terminal electrodes, which comprises a plurality of ceramic dielectric layers, a plurality of staggered inner electrodes are arranged in the plurality of ceramic dielectric layers, at least one ceramic dielectric layer is arranged between the inner electrodes, and two ends of the staggered inner electrodes are electrically connected with the terminal electrodes through outer electrodes respectively. A fusion section is arranged between the outer electrode and the end electrode, and the outer electrode or the end electrode extends in the horizontal direction at the position of the fusion section, so that the contact area between the outer electrode and the end electrode is increased. By adopting the scheme, the contact area between the outer electrode and the terminal electrode can be increased, and the bonding strength between the outer electrode and the terminal electrode can be improved. In the optional scheme, the deformation resistance between the outer electrode and the end electrode can be improved, and the thermal shock deformation resistance and mechanical deformation resistance of the MLCC capacitor can be greatly improved by combining the thickened bottom plate structure.

Description

Technical Field

[0001] The present invention relates to the field of MLCC capacitor preparation, and in particular to an MLCC capacitor with fused end electrodes and a preparation method thereof. Background Art

[0002] MLCC (Multi-layer Ceramic Chip Capacitors) is also known as monolithic capacitors. The current market demand is mainly in digital products and automotive electronic product applications. In automotive electronics, computers and other products, the temperature changes greatly and there are mechanical shocks, which require high mechanical strength of MLCC. In application scenarios with large temperature changes and mechanical shocks, MLCC is prone to cracking at the welding position. This cracking structure may cause the external electrode or the internal electrode to break, misalign or short-circuit, resulting in reduced MLCC capacitance, MLCC failure, or even MLCC short-circuit, which poses risks to automotive circuits or electronic products such as computers that use the MLCC. In failure conditions, desoldering of the external electrode and the terminal electrode is one of the forms of failure. The structure after desoldering is as follows: Figure 7 In the prior art, glass powder is added to the terminal electrode slurry so that part of the terminal electrode slurry can penetrate between the external electrode and the ceramic dielectric layer to increase the connection strength between the terminal electrode and the external electrode. However, after testing, it is found that the infiltrated terminal electrode slurry is mainly glass, which has insufficient conductivity, and the material is brittle and easily broken to form a hollow structure, such as Figure 7 as shown in . Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an MLCC capacitor with fused terminal electrodes and a preparation method, which can greatly increase the contact area between the terminal electrode and the external electrode, thereby increasing the connection strength between the terminal electrode and the external electrode. In the preferred scheme, it can ensure that the terminal electrode and the external electrode can withstand deformation within a certain range without detaching.

[0004] In order to solve the above-mentioned technical problems, the technical solution of the present invention is: an MLCC capacitor with fused terminal electrodes, comprising a multi-layer ceramic dielectric layer, a multi-layer staggered internal electrode is arranged in the multi-layer ceramic dielectric layer, at least one ceramic dielectric layer is arranged between the internal electrodes, the two ends of the staggered internal electrodes are electrically connected to the terminal electrodes through external electrodes respectively, a fusion section is provided between the external electrode and the terminal electrode, and at the position of the fusion section, the external electrode or the terminal electrode extends in a horizontal direction to increase the contact area between the external electrode and the terminal electrode.

[0005] In a preferred solution, a groove extending along the external electrode is provided at the position of the external electrode, and the terminal electrode extends toward the external electrode and is connected to the external electrode.

[0006] In a preferred embodiment, the ceramic dielectric layer is divided into a first component and a second component, a ceramic dielectric layer of the second component is provided at the free end of the outer electrode, and the ceramic dielectric layers of the first component and the second component have different resonance frequencies; The free end portion of the external electrode extends outside the ceramic dielectric layer of the second component, so that the free end of the external electrode is covered by the terminal electrode.

[0007] In a preferred embodiment, the ceramic dielectric layer of the first component is Ba 1-x Ca x TiO3, x is 0.03~0.12; the ceramic dielectric layer of the second component is BaTiO3.

[0008] In a preferred embodiment, a thickening layer is provided at the bottom of the ceramic dielectric layer, and the thickness of the thickening layer is greater than the thickness of the ceramic dielectric layer between the inner electrodes; The thickening layer is formed by stacking at least two ceramic dielectric layers, and an isolation layer is provided between the ceramic dielectric layers of the thickening layer; The isolation layer is a carbonized layer or a flexible resin layer.

[0009] A method for preparing the above-mentioned MLCC capacitor with fused end electrodes comprises the following steps: Before the end-sealing step, the free ends of the blank corresponding to the external electrodes at both ends are corroded to form grooves at the positions of the external electrodes; The types of corrosion include acid corrosion and cavitation.

[0010] In a preferred embodiment, the preparation method specifically comprises the following steps: S01, coating the acid solution on the two ends of the blank corresponding to the outer electrode; The acid solution includes a mixture of one or more of sulfuric acid and nitric acid and deionized water; S02. After the groove is formed at the position of the outer electrode, it is washed with deionized water; S03, after drying the blank, performing a capping operation in a terminal electrode slurry under a negative pressure environment; S04, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode; Through the above steps, a fusion section is formed between the outer electrode and the terminal electrode.

[0011] In another optional scheme, the preparation method specifically comprises the following steps: S11, covering the side wall of the blank with a flexible coating so that the two ends of the blank corresponding to the external electrodes are exposed; S12, placing the coated blank in a liquid to generate bubbles for cavitation; S13, forming a groove at the position of the outer electrode; S14, after the blank is dried, a terminal capping operation is performed in a terminal electrode slurry under a negative pressure environment; S15, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode; Through the above steps, a fusion section is formed between the outer electrode and the terminal electrode.

[0012] A method for preparing the above-mentioned MLCC capacitor with fused end electrodes comprises the following steps: S21, preparing the ceramic slurry Ba of the first component 1-x Ca x TiO3, x is 0.03~0.12; Preparing a second component ceramic slurry BaTiO3; S22, laying out the ceramic slurries of the first component and the second component at the same time, wherein the ceramic slurry of the second component is arranged at a position corresponding to the external electrode; S23, printing an electrode layer on the surface of the dried ceramic dielectric layer, wherein the external electrode is printed at a position corresponding to the ceramic dielectric layer of the second component; S24, before the end-capping step, resonantly crushing the ceramic dielectric layer of the second component in a resonant manner to expose the external electrode; S25, end-capping operation; S26, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode; Through the above steps, a fusion section is formed between the outer electrode and the terminal electrode.

[0013] In a preferred solution, step S24 includes the following steps: S241: preparing a ceramic dielectric layer sample of the second component, and detecting the natural frequency of the sample; S242, the middle part of the blank is suspended and clamped, and the two ends corresponding to the external electrodes are in contact with the exciting head. The exciting head excites the two ends of the blank at the natural frequency to break the ceramic dielectric layer of the second component and expose the external electrode.

[0014] The present invention provides an MLCC capacitor with fused terminal electrodes and a preparation method. By adopting the above scheme, the contact area between the external electrode and the terminal electrode can be increased, and the bonding strength between the external electrode and the terminal electrode can be improved. In an optional scheme, the deformation resistance between the external electrode and the terminal electrode can be improved, and combined with the thickened bottom plate structure, the ability of the MLCC capacitor to resist thermal shock deformation and mechanical deformation can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 It is a structural schematic diagram of the present invention.

[0016] Figure 2 It is a structural schematic diagram of another preferred embodiment of the present invention.

[0017] Figure 3 It is a structural schematic diagram of another preferred embodiment of the present invention.

[0018] Figure 4 It is a schematic diagram of the structure of the fusion section between the outer electrode and the end electrode in the present invention.

[0019] Figure 5 This is another preferred structural schematic diagram of the fusion section between the outer electrode and the end electrode in the present invention.

[0020] Figure 6 It is a schematic diagram of the structure of resonance processing of the blank in the present invention.

[0021] Figure 7 It is a schematic diagram of the structure after the end electrode and the outer electrode are hollowed out in the prior art.

[0022] In the figure: end electrode 1, ceramic dielectric layer 2, inner electrode 3, bottom plate thickness 4, opening length 5, resin layer 6, end electrode lining 7, outer electrode 8, thickening layer 9, fusion section 10, blank 11, clamping device 12, exciting head 13, second component ceramic dielectric layer 14, first component ceramic dielectric layer 15. DETAILED DESCRIPTION

[0023] The MLCC capacitor processing technology in the prior art includes the following steps: Preparation of ceramic slurry for the ceramic dielectric layer. In this example, BaTiO3 or Ba 1-x Ca x TiO3, x is 0.03~0.12, → ceramic slurry is cast and spread, dried → electrode layer is printed on the surface of ceramic dielectric layer → lamination, ceramic dielectric layer with electrode layer is laminated, electrode layer is staggered → the laminated capacitor semi-finished product is compacted → cutting, single capacitor blank is made → debonding, glue is evaporated and discharged at 600℃, about 3h~5h, preferably 4h → sintering, ceramic dielectric layer in capacitor is sintered, sintering temperature is usually 1000℃~1250℃ → chamfering, chamfering the edge of sintered capacitor → sealing, terminal electrode slurry is respectively coated on both ends of capacitor, usually a combination of one or more of silver, copper and nickel, and electrically connected to external electrode → sintering end, so that terminal electrode slurry is solidified into terminal electrode 1, sintering temperature is 800℃ → electroplating, nickel layer and tin layer are plated on terminal electrode 1 respectively.

[0024] For ease of description: In this example, the semi-finished capacitor product without terminal electrodes after stacking is called a blank.

[0025] The overlapping portion of the electrode layers is called the internal electrode 3, and the interlaced and un-overlapped portion is called the external electrode 12.

[0026] The technical solution of the present invention is described in detail below. Parts not specifically described are all within the prior art.

[0027] Embodiment 1: like Figures 1 to 5 In the invention, a MLCC capacitor with fused terminal electrodes includes a multi-layer ceramic dielectric layer 2, a multi-layer staggered internal electrode 3 is arranged in the multi-layer ceramic dielectric layer 2, at least one layer of ceramic dielectric layer 2 is arranged between the internal electrodes 3, the two ends of the staggered internal electrodes 3 are electrically connected to the terminal electrode 1 through the external electrode 12, a fusion section 10 is arranged between the external electrode 12 and the terminal electrode 1, and at the position of the fusion section 10, the external electrode 12 or the terminal electrode 1 extends in the horizontal direction to increase the contact area between the external electrode 12 and the terminal electrode 1. With this structure, the connection strength and anti-deformation strength between the external electrode 12 and the terminal electrode 1 are greatly improved. When the MLCC capacitor cracks along the welding position of the terminal electrode 1, the external electrode 12 and the terminal electrode 1 remain tightly connected and will not be detached.

[0028] The preferred solution is Figure 4 In the embodiment, a groove extending along the external electrode 12 is provided at the position of the external electrode 12, and the terminal electrode 1 extends in the direction of the external electrode 12 and is connected to the external electrode 12. With this structure, the contact area between the external electrode 12 and the terminal electrode 1 is increased, and the connection strength is improved. Compared with the terminal electrode slurry infiltration structure in the prior art, the strength is higher and the wire performance is stronger.

[0029] Embodiment 2: On the basis of Example 1, a method for preparing the above-mentioned MLCC capacitor with fused terminal electrodes comprises the following steps: Before the end-capping step, the free ends corresponding to the external electrodes 8 at both ends of the blank are corroded to form grooves at the positions of the external electrodes 12; the external electrodes 12 and the internal electrodes 3 are printed by printing the electrode slurry onto the surface of the ceramic dielectric layer, and the electrode layer is tightly combined with the ceramic dielectric layer 2 by static pressure. The printing methods include gravure printing and screen printing. The electrode layers printed by these two methods are all mesh or dot structures, and part of the electrode layer and the ceramic dielectric layer 2 are mutually infiltrated and intertwined. Corrosion usually first corrodes the electrode layer with higher purity, which makes the Figure 4 The top and bottom walls of the corroded groove still retain a large amount of electrode layer. When the groove is filled with the terminal electrode 1, the remaining electrode layer and the terminal electrode 1 are fused with each other with a large contact area to form a fusion section 10 with high strength and high conductivity.

[0030] The types of corrosion include acid corrosion and cavitation.

[0031] In a preferred embodiment, the preparation method specifically comprises the following steps: S01, coating the acid solution on the two ends of the blank corresponding to the outer electrode 8; The acid solution includes a mixture of one or more of sulfuric acid and nitric acid and deionized water; in this example, the mass ratio of acid solution to water is preferably 0.3-0.5:1, wherein the mass ratio of sulfuric acid to nitric acid is 1-2:1. The sulfuric acid is about 98% by mass, and the nitric acid is about 68% by mass.

[0032] S02. After the groove is formed at the position of the outer electrode 8, a suitable etching time is selected according to the size of the MLCC capacitor, and the MLCC capacitor is first rinsed with deionized water, then washed with sodium hydroxide solution, and then rinsed with deionized water again; S03. After the blank is dried, a sealing operation is performed in a terminal electrode slurry under a negative pressure environment; the terminal electrode slurry is a terminal electrode slurry commonly used in the prior art, such as silver Ag slurry, nickel Ni slurry, copper Cu slurry or a composite slurry of the above slurries, or a composite slurry of the above slurries and glass powder.

[0033] S04, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode 1; for metal slurry, the sintering temperature is 800°C, and for composite slurry containing organic matter, the sintering temperature is 250°C~290°C. The sintering temperature used in this example is 800°C. The terminal electrode 1 thus formed has higher strength.

[0034] Through the above steps, a fusion section is formed between the external electrode 8 and the terminal electrode 1. The remaining processing steps are the same as the processing steps of the MLCC capacitor in the prior art.

[0035] Embodiment 3: Based on Example 1, in another optional scheme, the preparation method specifically includes the following steps: S11, coating the side wall of the blank with a flexible coating, the flexible coating comprising rubber or silicone, the flexible coating may be coated on the outside of the blank or the blank may be placed in a rubber or silicone sleeve, and then cut according to the length of the sheet so that both ends of the blank corresponding to the outer electrode 8 are exposed; S12, placing the coated blank in deionized water to generate bubbles for cavitation; using laser or electrode to generate bubbles in the water near the blank, the cavitation time is about 2 hours, the cavitation usually develops along the length direction of the outer electrode 8, and the cavitation is generated at the interface between the outer electrode 8 and the ceramic dielectric layer 2. That is, cavitation usually first corrodes the interface between the outer electrode 8 and the ceramic dielectric layer 2, so that the outer electrode 8 remains relatively intact.

[0036] S13, a groove is formed at the position of the external electrode 8; the groove formed by cavitation can retain a relatively complete external electrode 8, thereby increasing the contact area between the external electrode 8 and the end electrode 1, and no other components remain, which is a more ideal groove forming process.

[0037] S14, after the blank is dried, a terminal capping operation is performed in a terminal electrode slurry under a negative pressure environment; S15, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode 1; Through the above steps, a fusion section is formed between the external electrode 8 and the terminal electrode 1.

[0038] Embodiment 4: The preferred solution is Figure 3 , 5 In ~6, the ceramic dielectric layer 2 is divided into a first component and a second component, a second component ceramic dielectric layer 14 is provided at the free end of the external electrode 12, and a first component ceramic dielectric layer 15 is provided at the remaining position, and the first component ceramic dielectric layer 15 and the second component ceramic dielectric layer 14 have different resonance frequencies; The free end portion of the external electrode 12 extends outside the ceramic dielectric layer 2 of the second component, so that the free end of the external electrode 12 is covered by the terminal electrode 1 .

[0039] In a preferred embodiment, the ceramic dielectric layer 2 of the first component is Ba 1-x Ca x TiO3, x is 0.03-0.12; the ceramic dielectric layer 2 of the second component is BaTiO3.

[0040] Embodiment 5: On the basis of Example 4, a method for preparing the above-mentioned MLCC capacitor with fused terminal electrodes comprises the following steps: S21, preparing the ceramic slurry Ba of the first component 1-x Ca x TiO3, x is 0.03~0.12; Ba 1-x Ca x The preparation method of TiO3, x is 0.03~0.12 is to use BaCl2·H2O, CaCl2 and H2TiO3 as raw materials, according to Ba 1-x Ca xThe raw materials are proportioned in a stoichiometric ratio of 0.03, 0.06, 0.09, and 0.12. BaCl2·H2O and CaCl2 are dissolved in a certain amount of deionized water, and H2TiO3 is dispersed in a certain amount of ethanol. The two are mixed and stirred evenly, and then KOH solution is dropped into the mixture. After mixing evenly, the mixture is placed in an oven at 210°C for reaction for 22 to 24 hours. After cooling, the sample is taken out and washed with deionized water, filtered, and dried to obtain Ba 1-x Ca x TiO3 powder sample. The obtained powder is added with a polyvinyl alcohol (PVA) solution with a mass concentration of 5% as a binder to obtain a ceramic slurry of the first component ceramic dielectric layer 15. The ceramic slurry of the first component ceramic dielectric layer 15 has a debinding temperature of 600°C, a sintering temperature of 1250°C, and a sintering time of 2h.

[0041] Preparing a second component ceramic slurry BaTiO3; S22, laying out the ceramic slurries of the first component and the second component at the same time by inkjet printing, wherein the ceramic slurry of the second component is arranged at a position corresponding to the external electrode 8; S23, printing an electrode layer on the surface of the dried ceramic dielectric layer 2, and printing an external electrode 8 at a position corresponding to the ceramic dielectric layer 2 of the second component; like Figures 1 to 3 In the figure, the inner electrode 3 refers to the portion where the projections of the electrode layers overlap, and the outer electrode 12 refers to the portion where the electrode layers are staggered and not stacked.

[0042] S24, before the end-capping step, the ceramic dielectric layer 2 of the second component is resonantly crushed in a resonant manner to expose part of the external electrode 8; The preferred solution is Figure 6 In step S24, the following steps are included: S241: Prepare a sample of the ceramic dielectric layer 2 of the second component and detect the natural frequency of the sample; prepare samples of different volumes with a proportional amplification structure, fix the samples, vibrate them with an exciting hammer, collect the vibration curves of each sample with a vibration sensor, perform Fourier expansion, analyze and obtain the natural frequencies of each order of the current sample, compare the natural frequencies of samples of different volumes, and analyze and obtain the optimal natural frequency and natural frequency range.

[0043] S242, such as Figure 6In the process, the middle part of the blank is suspended and fixed by the clamping device 12, and the two ends corresponding to the external electrode 8 are in contact with the excitation head 13. The excitation head 13 uses an excitation head 13 with multiple blades, and the blades are arranged along the height direction of the MLCC capacitor, that is, the blades and the external electrode 8 are perpendicular to each other. In this example, a 5-8 blade excitation head is used. The excitation head 13 excites the two ends of the blank at the natural frequency, and the excitation time is 1s to 20s, so that the ceramic dielectric layer 2 of the second component is partially broken, and the external electrode 8 is exposed after rinsing with deionized water. This example is suitable for MLCC capacitors with a length greater than 3mm.

[0044] S25, end-capping operation; S26, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode 1; Through the above steps, a fusion section 10 is formed between the external electrode 8 and the terminal electrode 1. The fusion section 10 formed by this method has a higher connection strength between the external electrode 8 and the terminal electrode 1, and also has a higher anti-deformation strength between the external electrode 8 and the terminal electrode 1. Under this structure, even if the opening length 5 between the terminal electrodes 1 at both ends of the MLCC capacitor changes due to thermal shock or mechanical stress, the external electrode 8 and the terminal electrode 1 will not be separated within a certain range.

[0045] Embodiment 6: Based on the above embodiments, the preferred solution is as follows Figure 1 In the embodiment, a thickening layer 9 is provided at the bottom of the ceramic dielectric layer 2, and the thickness of the thickening layer 9 is greater than the thickness of the ceramic dielectric layer 2 between the internal electrodes 3; The thickening layer 9 is formed by stacking at least two ceramic dielectric layers 2, and an isolation layer is provided between the ceramic dielectric layers 2 of the thickening layer 9; The isolation layer is a carbonized layer or a flexible resin layer. With this structure, when the MLCC capacitor is subjected to thermal shock or mechanical stress, even if the thickened layer 9 is disconnected under the pulling force of the terminal electrode 1, it will not grow toward the upper ceramic dielectric layer 2, but will grow along the isolation layer. In combination with the schemes of embodiments 1 to 5, the terminal electrode 1 and the external electrode 8 will not be disconnected even if subjected to thermal shock or mechanical stress, thereby extending the service life of the MLCC capacitor.

[0046] Embodiment 7: The preferred solution is Figure 2 In the embodiment, a terminal electrode liner 7 is provided between the external electrode and the terminal electrode 1, and the coverage of the terminal electrode liner 7 is the same as that of the terminal electrode 1, and the terminal electrode liner 7 is made of conductive resin.

[0047] In the preferred solution, the terminal electrode liner 7 is provided with a thickened structure near the bottom. With this structure, the deformation of the MLCC capacitor when it is subjected to thermal shock or mechanical stress can be compensated by the self-deformation of the terminal electrode liner 7. In combination with the solutions of embodiments 1 to 5, even if subjected to thermal shock or mechanical stress, the terminal electrode 1 and the external electrode 8 have sufficient strength or toughness and will not be disconnected, thereby extending the service life of the MLCC capacitor and greatly improving the reliability of the MLCC capacitor.

[0048] Embodiment 8: On the basis of Example 7, Figure 2 As shown in , a method for preparing the above-mentioned MLCC capacitor with fused terminal electrodes comprises the following steps: S001, after the sintering step, a resin layer 6 is provided at the bottom of the blank; S002, sealing and sintering the ends with a conductive resin to form an end electrode liner 7; S003, electroplating at least two metal layers outside the terminal electrode lining 7 to form a terminal electrode 1; The conductive resin comprises, by mass percentage, 65% to 72% of conductive metal powder, 5% to 10% of thermosetting resin, 10% to 20% of additives, and 5% to 10% of organic solvent; The conductive metal powder includes more than 60% of flake or filament structures; Through the above steps, an MLCC capacitor with fused end electrodes is obtained.

[0049] In a preferred embodiment, the metal powder is made of one or more of silver, nickel or copper; The resin layer 6 is made of thermosetting resin; Thermosetting resins include one or more combinations of polyimide resins, polyamide resins, polyurethane resins, acrylic resins, polybutadiene resins, polyester resins, urea resins, epoxy resins, oxetane resins, phenoxy resins, polyamideimide resins, phenolic resins, cresol resins, melamine resins, alkyd resins, amino resins or polylactic acid resins; The additive is a combination of one or more of polyvinyl butyral, ethyl cellulose and polyvinyl alcohol; The organic solvent is anhydrous ethanol; The firing temperature is 200° C. to 290° C.; this method adopts a low-temperature firing process of the conductive resin, so as not to affect the performance of the resin layer 6 .

[0050] The inner metal layer of the electroplating is a nickel-plated layer, and the outer metal layer is a tin-plated layer.

[0051] By the above method, the thickened structure of the terminal electrode liner 7 can provide sufficient elastic deformation, so as to cope with the deformation caused by thermal expansion and contraction and mechanical stress caused by thermal shock. In combination with the schemes of Examples 1 to 5, even if subjected to thermal shock or mechanical stress, the terminal electrode 1 and the external electrode 8 have sufficient strength or toughness and will not be disconnected, thereby extending the service life of the MLCC capacitor and greatly improving the reliability of the MLCC capacitor.

[0052] Embodiment 9: On the basis of Example 7, Figure 2 As shown in , a method for preparing the above-mentioned fused terminal electrode MLCC capacitor comprises the following steps: S11, in the terminal sealing step, prefabricating a "C"-shaped terminal sealing shell, wherein the height of the "C"-shaped terminal sealing shell is higher than the height of the blank; S012, filling metallurgical powder in a "C"-shaped end-sealing shell, placing both ends of the blank in the "C"-shaped end-sealing shell, wherein the filling thickness of the metallurgical powder at the bottom of the "C"-shaped end-sealing shell is higher than the filling thickness at the top; The metallurgical powder is a conductive metal powder, wherein by mass percentage, 80% to 95% of the conductive metal powder and 5% to 20% of the additive; The conductive metal powder is a combination of one or more of silver, copper, and nickel, and the additive is a combination of one or more of polyvinyl butyral, ethyl cellulose, and polyvinyl alcohol; through the above steps, an MLCC capacitor with fused terminal electrodes is obtained. By the above method, the sintered metallurgical powder constitutes the terminal electrode lining 7, and the thickened structure of the terminal electrode lining 7 can provide sufficient elastic deformation, so as to cope with the deformation caused by thermal expansion and contraction and mechanical stress caused by thermal shock. The "C"-shaped end-sealing shell is first made, and then the end-sealing shell is connected to the blank by powder casting, so that the process can be suitable for traditional production processes, that is, the end-sintering process at a high temperature of 800°C. The present invention can be put into production after simply modifying the existing process route, reducing the investment in technical transformation. In conjunction with the schemes of Examples 1 to 5, even if the terminal electrode 1 and the external electrode 8 are subjected to thermal shock or mechanical stress, there is sufficient strength or toughness and will not be disconnected, which extends the service life of the MLCC capacitor and greatly improves the reliability of the MLCC capacitor.

[0053] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An MLCC capacitor with integrated terminal electrodes, comprising a plurality of ceramic dielectric layers (2), a plurality of staggered internal electrodes (3) being arranged in the plurality of ceramic dielectric layers (2), at least one ceramic dielectric layer (2) being arranged between the internal electrodes (3), and both ends of the staggered internal electrodes (3) being electrically connected to the terminal electrodes (1) via external electrodes (12), wherein: A fusion section (10) is provided between the external electrode (12) and the terminal electrode (1); at the position of the fusion section (10), the external electrode (12) or the terminal electrode (1) extends in a horizontal direction, so that the contact area between the external electrode (12) and the terminal electrode (1) is increased.

2. The MLCC capacitor with fused terminal electrodes according to claim 1, characterized in that: A groove extending along the external electrode (12) is provided at the position of the external electrode (12), and the end electrode (1) extends in the direction of the external electrode (12) and is connected to the external electrode (12).

3. The MLCC capacitor with fused terminal electrodes according to claim 1, characterized in that: The ceramic dielectric layer (2) is divided into a first component and a second component, the ceramic dielectric layer (2) of the second component is provided at the free end of the external electrode (12), and the ceramic dielectric layers (2) of the first component and the second component have different resonance frequencies; The free end portion of the external electrode (12) extends outside the ceramic dielectric layer (2) of the second component, so that the free end of the external electrode (12) is covered by the terminal electrode (1).

4. The MLCC capacitor with fused terminal electrodes according to claim 3 is characterized in that: The first component of the ceramic dielectric layer (2) is Ba 1-x Ca x TiO3, x is 0.03-0.12; the ceramic dielectric layer (2) of the second component is BaTiO3.

5. The MLCC capacitor with fused end electrodes according to any one of claims 1 to 5, characterized in that: A thickening layer (9) is provided at the bottom of the ceramic dielectric layer (2), and the thickness of the thickening layer (9) is greater than the thickness of the ceramic dielectric layer (2) between the internal electrodes (3); The thickening layer (9) is formed by stacking at least two ceramic dielectric layers (2), and an isolation layer is provided between the ceramic dielectric layers (2) of the thickening layer (9); The isolation layer is a carbonized layer or a flexible resin layer.

6. A method for preparing an MLCC capacitor with fused end electrodes as claimed in any one of claims 1 to 2 and 5, characterized in that The following steps are involved: Before the end-sealing step, the free ends of the blank corresponding to the external electrodes (8) at both ends are corroded to form grooves at the positions of the external electrodes (12); The types of corrosion include acid corrosion and cavitation.

7. The method for preparing a MLCC capacitor with fused terminal electrodes according to claim 6, characterized in that The following steps are involved: S01, applying acid solution to the two ends of the blank corresponding to the outer electrode (8) by coating; The acid solution includes a mixture of one or more of sulfuric acid and nitric acid and deionized water; S02, after a groove is formed at the position of the outer electrode (8), washing with deionized water; S03, after drying the blank, performing a capping operation in a terminal electrode slurry under a negative pressure environment; S04, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode (1); Through the above steps, a fusion section is formed between the outer electrode (8) and the end electrode (1).

8. The method for preparing a MLCC capacitor with fused terminal electrodes according to claim 6, characterized in that The following steps are involved: S11, coating the side wall of the blank with a flexible coating so that the two ends of the blank corresponding to the external electrode (8) are exposed; S12, placing the coated blank in a liquid to generate bubbles for cavitation; S13, forming a groove at the position of the outer electrode (8); S14, after the blank is dried, a terminal capping operation is performed in a terminal electrode slurry under a negative pressure environment; S15, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode (1); Through the above steps, a fusion section is formed between the outer electrode (8) and the end electrode (1).

9. A method for preparing an MLCC capacitor with fused end electrodes as claimed in any one of claims 3 to 5, characterized in that The following steps are involved: S21, preparing the ceramic slurry Ba of the first component 1-x Ca x TiO3, x is 0.03~0.12; Preparing a second component ceramic slurry BaTiO3; S22, laying out the ceramic slurries of the first component and the second component simultaneously, wherein the ceramic slurry of the second component is arranged at a position corresponding to the external electrode (8); S23, printing an electrode layer on the surface of the dried ceramic dielectric layer (2), wherein the external electrode (8) is printed at a position corresponding to the ceramic dielectric layer (2) of the second component; S24, before the end-capping step, resonantly crushing the ceramic dielectric layer (2) of the second component in a resonant manner to expose the external electrode (8); S25, end-capping operation; S26, sintering the terminal to solidify the terminal electrode slurry into a terminal electrode (1); Through the above steps, a fusion section is formed between the outer electrode (8) and the end electrode (1).

10. The method for preparing a MLCC capacitor with fused terminal electrodes according to claim 9, characterized in that Step S24 includes the following steps: S241: preparing a sample of a ceramic dielectric layer (2) of the second component, and detecting the natural frequency of the sample; S242, the middle part of the blank is suspended and clamped, and the two ends corresponding to the external electrode (8) are in contact with the exciting head (13), and the exciting head (13) excites the two ends of the blank at a natural frequency to break the ceramic dielectric layer (2) of the second component and expose the external electrode (8).

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