CN116798717A - Coating of metal oxide varistors - Google Patents
Coating of metal oxide varistors Download PDFInfo
- Publication number
- CN116798717A CN116798717A CN202210254194.2A CN202210254194A CN116798717A CN 116798717 A CN116798717 A CN 116798717A CN 202210254194 A CN202210254194 A CN 202210254194A CN 116798717 A CN116798717 A CN 116798717A
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- CN
- China
- Prior art keywords
- varistor body
- over
- insulating coating
- lead
- coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 54
- 239000011248 coating agent Substances 0.000 title claims abstract description 51
- 229910044991 metal oxide Inorganic materials 0.000 title claims abstract description 12
- 150000004706 metal oxides Chemical class 0.000 title claims abstract description 12
- 229920006334 epoxy coating Polymers 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims description 33
- 238000001465 metallisation Methods 0.000 claims description 20
- 239000003973 paint Substances 0.000 claims description 14
- 239000004593 Epoxy Substances 0.000 claims description 9
- 238000000151 deposition Methods 0.000 claims description 7
- 229920000647 polyepoxide Polymers 0.000 claims description 7
- 229920000178 Acrylic resin Polymers 0.000 claims description 6
- 229920005749 polyurethane resin Polymers 0.000 claims description 6
- 229920002050 silicone resin Polymers 0.000 claims description 6
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 claims description 5
- 229920000180 alkyd Polymers 0.000 claims description 5
- 239000004814 polyurethane Substances 0.000 claims description 5
- 229910052709 silver Inorganic materials 0.000 claims description 5
- 239000004332 silver Substances 0.000 claims description 5
- 230000001680 brushing effect Effects 0.000 claims description 2
- 238000007598 dipping method Methods 0.000 claims description 2
- 238000005507 spraying Methods 0.000 claims description 2
- 239000002966 varnish Substances 0.000 claims 2
- 239000004922 lacquer Substances 0.000 claims 1
- 239000005871 repellent Substances 0.000 claims 1
- 238000005476 soldering Methods 0.000 claims 1
- 239000000919 ceramic Substances 0.000 description 6
- 239000003292 glue Substances 0.000 description 5
- -1 AR type) Polymers 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 230000014509 gene expression Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000004925 Acrylic resin Substances 0.000 description 1
- 239000002519 antifouling agent Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- LNEPOXFFQSENCJ-UHFFFAOYSA-N haloperidol Chemical compound C1CC(O)(C=2C=CC(Cl)=CC=2)CCN1CCCC(=O)C1=CC=C(F)C=C1 LNEPOXFFQSENCJ-UHFFFAOYSA-N 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920000052 poly(p-xylylene) Polymers 0.000 description 1
- 239000003223 protective agent Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C10/00—Adjustable resistors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C1/00—Details
- H01C1/02—Housing; Enclosing; Embedding; Filling the housing or enclosure
- H01C1/034—Housing; Enclosing; Embedding; Filling the housing or enclosure the housing or enclosure being formed as coating or mould without outer sheath
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C1/00—Details
- H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
- H01C17/02—Apparatus or processes specially adapted for manufacturing resistors adapted for manufacturing resistors with envelope or housing
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
- H01C17/28—Apparatus or processes specially adapted for manufacturing resistors adapted for applying terminals
Abstract
The invention discloses a coating of a metal oxide varistor. A Metal Oxide Varistor (MOV) may include: a varistor body including a first side and a second side opposite the first side; and a first lead connected to the varistor body along a first side and a second lead connected to the varistor body along a second side. The MOV further comprises: over the first and second sides of the varistor body, including an insulating coating over the first and second leads; and an epoxy coating over the insulating coating.
Description
Technical Field
Embodiments relate to the field of circuit protection devices, and more particularly, to Metal Oxide Varistor (MOV) coatings and methods for forming MOV coatings.
Background
Overvoltage protection devices are used to protect electronic circuits and components from damage from overvoltage fault conditions. These overvoltage protection devices may include a Metal Oxide Varistor (MOV) connected between the circuit to be protected and ground. MOVs have current-voltage characteristics that allow the MOVs to be used to protect such circuits from catastrophic voltage surges. MOVs typically consist of: a ceramic disc, often based on ZnO, an electrical contact layer acting as an electrode, such as an Ag (silver) electrode, and a first and a second metal lead connected at a first and a second surface, respectively, wherein the second surface is opposite to the first surface. In many cases, the MOV can also be provided with an epoxy coating around the ceramic disc and other materials. During manufacture, bubble defects may form in the epoxy coating, which results in openings being formed through the epoxy coating and damage to the protective device.
It is with respect to this and other deficiencies of the prior art that the present disclosure is provided.
Disclosure of Invention
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In one method, a Metal Oxide Varistor (MOV) may include: a varistor body including a first side and a second side opposite the first side; a first lead connected to the varistor body along a first side and a second lead connected to the varistor body along a second side; an insulating coating over the first and second sides of the varistor body (including over the first and second leads); and an epoxy coating over the insulating coating.
In another method, a method of forming a Metal Oxide Varistor (MOV) may include: providing a varistor body comprising a first side and a second side opposite the first side; connecting a first lead to the varistor body along a first side and a second lead to the varistor body along a second side; forming an insulating coating over the first and second sides of the varistor body, including over the first and second leads; and forming an epoxy coating over the insulating coating.
In yet another method, a method of forming a Metal Oxide Varistor (MOV) may include: providing a varistor body comprising a first side and a second side opposite the first side; forming a metallization layer along a first side or a second side of the varistor body; a first lead is soldered to the varistor body along a first side and a second lead is connected to the varistor body along a second side. The method may further comprise: forming an insulating coating over the first and second sides of the varistor body, including over the first and second leads and the metallization layer; and forming an epoxy coating over the insulating coating.
Drawings
The accompanying drawings illustrate exemplary methods of the disclosed embodiments that have been designed heretofore for the practical application of the principles of the disclosed embodiments, and in which:
FIG. 1 is a perspective view of an MOV according to an embodiment of the present disclosure;
figure 2 is a side cross-sectional view of the MOV of figure 1 in accordance with an embodiment of the disclosure; and is also provided with
Fig. 3 is a flow chart of a method according to an embodiment of the present disclosure.
The drawings are not necessarily to scale. The drawings are merely representations, not intended to portray specific parameters of the disclosure. The drawings are intended to depict exemplary embodiments of the disclosure, and therefore should not be considered as limiting the scope. In the drawings, like numbering represents like elements.
Moreover, certain elements in some of the figures may be omitted or not shown to scale for clarity of illustration. For clarity of illustration, the cross-sectional view may be in the form of a "slice" or "near" cross-sectional view, omitting certain background lines that would otherwise be visible in a "true" cross-sectional view. Moreover, some reference numerals may be omitted from some of the figures for clarity.
Detailed Description
Apparatus and methods according to the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. The apparatus and method may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
As described in more detail herein, embodiments of the present disclosure provide an effective way to eliminate the bubble problem typically found in MOV coatings by first applying a tri-proof paint layer on top of the MOV prior to the formation of the outer MOV coating.
Turning to fig. 1-2, an apparatus or device 100 (e.g., MOV) in accordance with an embodiment of the present disclosure will be described. The device 100 may include a varistor body 102 having a first side 103 opposite a second side 104. The varistor body 102 may also include a metallization layer 106 along the first side 103 and/or the second side 104 of the varistor body 102. In some embodiments, the varistor body 102 is ceramic (e.g., based on ZnO), and the metallization layer 106 is an electrical contact having one or more layers of silver (Ag) or other types of electrical conductors that are operable to provide good electrical contact between the ceramic varistor body 102 and one or more external electrical leads 110A-B. As shown, the electrical leads 110A-B may include a first metal lead 110A and a second metal lead 110B connected to respective first and second metallization layers 106. It should be appreciated that one or more additional leads may be present in alternative embodiments.
As shown, the device 100 may also include an insulating coating 120 over the first side 103 and the second side 104 of the varistor body 102 (including over the first and second leads 110A-B). The insulating coating 120 may be conformally deposited directly atop the first and second leads 110A-B and directly atop the metallization layer 106. In some embodiments, the insulating coating 120 is a tri-proof paint layer, including at least one of: acrylic, silicone, polyurethane, epoxy, and alkyd resins. The three-proofing paint can also be called a three-proofing glue, a dampproofing glue, an insulating glue, a dampproofing paint, a protective paint, a coating glue, a waterproof glue, a dampproofing oil, a three-proofing agent, a protective agent, a dampproofing agent, a conformal coating, a common coating or a compliant coating. The three-proofing paint may include: acrylic resin (e.g., AR type), epoxy resin (e.g., ER type), silicone resin (e.g., SR type), polyurethane resin (e.g., UR type), and parylene (XY type). The use of a tri-proof paint may provide moisture, mildew, dust protection to the device 100, and provide improved insulation and durability. The tri-proof paint may also greatly reduce dendrite growth and relieve stresses in the device 100. Generally, the three-proofing paint application process includes brushing, spraying, dipping, and/or selective coating. The insulating coating 120 may be cured at an elevated temperature or at room temperature.
As further shown, the device 100 may include an epoxy coating 125 formed over the insulating coating 120. In some embodiments, the epoxy coating 125 is a conformal material layer formed directly atop the insulating coating 120. Examples of suitable epoxy resins for the epoxy coating 125 include known epoxy materials used to form conventional MOV devices. The epoxy layer may encapsulate the painted ceramic body, protecting the ceramic body, such as by providing high dielectric strength.
Fig. 3 illustrates an example method 200 according to an embodiment of this disclosure. At block 201, the method 200 may include: a varistor body is provided that includes a first side and a second side opposite the first side. In some embodiments, a metallization layer (e.g., ag) is formed along at least one of the first and second sides of the varistor body.
At block 202, the method 200 may include: a first lead is connected to the varistor body along a first side and a second lead is connected to the varistor body along a second side. In some embodiments, the first and second leads are soldered directly to the metallization layer along the first and second sides of the varistor body, respectively.
At block 203, the method 200 may include: an insulating coating is formed over the first and second sides of the varistor body, including over the first and second leads. In some embodiments, forming the insulating coating includes conformally depositing the insulating coating over the varistor body, the first lead, and the second lead. In some embodiments, the insulating coating may be a three-proofing paint formulated with at least one of: acrylic, silicone, polyurethane, epoxy, and alkyd resins.
At block 204, the method 200 may include: an epoxy coating is formed over the insulating coating. In some embodiments, an epoxy coating is conformally formed over the insulating coating. In some embodiments, the epoxy coating is formed by immersing the device within a liquid epoxy material and drying/curing the epoxy. In some embodiments, the epoxy coating and/or insulating coating may be partially removed to provide access to one or more metallization layers.
The foregoing discussion has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure may be combined together in one or more aspects, embodiments, or configurations for the purpose of simplifying the disclosure. However, it should be understood that various features of certain aspects, embodiments, or configurations of the present disclosure may be combined in alternative aspects, embodiments, or configurations. Furthermore, the following claims are hereby incorporated into this detailed description by reference, with each claim standing on its own as a separate embodiment of this disclosure.
As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to "one embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.
The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Thus, the terms "comprising," "including," or "having," and variations thereof, are open-ended and are used interchangeably herein.
The phrases "at least one," "one or more," and/or "as used herein are open ended expressions that are both joined and separated in operation. For example, each of the expressions "at least one of A, B and C", "at least one of A, B or C", "one or more of A, B and C", "one or more of A, B or C", and "A, B and/or C" refers to a alone a, B alone, C, A and B together, a and C together, B and C together, or A, B and C together.
Moreover, identifying references (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to imply importance or priority, but rather are used to distinguish one feature from another. The drawings are for illustrative purposes only and the dimensions, positions, sequences and relative sizes reflected in the drawings herein may vary.
Furthermore, the terms "substantially" or "essentially" and the terms "approximately" or "approximately" may be used interchangeably in some embodiments and may be described using any relative metric acceptable to one of ordinary skill in the art. For example, these terms may be used as a comparison to a reference parameter to indicate a deviation that can provide the intended function. Although non-limiting, deviations from the reference parameter may be, for example, within amounts of less than 1%, less than 3%, less than 5%, less than 10%, less than 15%, less than 20%, etc.
Moreover, while the illustrative method 400 is described above as a series of acts or events, the present disclosure is not limited by the illustrated ordering of such acts or events, unless specifically stated. For example, some acts may occur in different orders and/or concurrently with other acts or events apart from those illustrated and/or described herein, in accordance with the disclosure. In addition, not all illustrated acts or events may be required to implement a methodology in accordance with the present disclosure. Furthermore, method 400 may be implemented in connection with the formation and/or processing of structures shown and described herein, as well as in connection with other structures not shown.
The scope of the present disclosure is not limited to the specific embodiments described herein. Indeed, various other embodiments and modifications of the present disclosure in addition to those described herein will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. Accordingly, such other embodiments and modifications are intended to fall within the scope of this disclosure. Furthermore, the present disclosure has been described herein in the context of particular embodiments in a particular environment for a particular purpose. Those of ordinary skill in the art will recognize that the usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below are to be construed in view of the full breadth and spirit of the present disclosure as described herein.
Claims (20)
1. A Metal Oxide Varistor (MOV) comprising:
a varistor body including a first side and a second side opposite the first side;
a first lead connected to the varistor body along the first side and a second lead connected to the varistor body along the second side;
an insulating coating over the first and second sides of the varistor body, including over the first and second leads; and
an epoxy coating over the insulating coating.
2. The MOV of claim 1, wherein the insulating coating is conformally formed over the varistor body, the first lead, and the second lead.
3. The MOV of claim 1, wherein the epoxy coating is conformally formed over the insulating coating.
4. The MOV of claim 1, the varistor body further comprising: a metallization layer along the first side or the second side of the varistor body, wherein the insulating coating is formed directly on top of the metallization layer.
5. The MOV of claim 4, wherein the metallization layer comprises silver.
6. The MOV of claim 1 wherein the insulating coating is a paint-repellent.
7. The MOV of claim 6, wherein the anti-paint comprises at least one of: acrylic, silicone, polyurethane, epoxy, and alkyd resins.
8. A method of forming a Metal Oxide Varistor (MOV), comprising:
providing a varistor body comprising a first side and a second side opposite the first side;
connecting a first lead to the varistor body along the first side and a second lead to the varistor body along the second side;
forming an insulating coating over the first and second leads, including over the first and second leads, over the first and second sides of the varistor body; and
an epoxy coating is formed over the insulating coating.
9. The method of claim 8, wherein forming the insulating coating comprises: conformally depositing the insulating coating over the varistor body, the first lead, and the second lead, and wherein forming the epoxy coating comprises: the epoxy coating is conformally deposited over the insulating coating.
10. The method of claim 8, further comprising disposing a metallization layer along at least one of the first side and the second side of the varistor body, wherein the insulating coating is formed directly atop the metallization layer.
11. The method of claim 10, wherein disposing the metallization layer comprises: silver is deposited along at least one of the first and second sides of the varistor body.
12. The method of claim 8, wherein forming the insulating coating comprises: depositing a varnish over the first and second sides of the varistor body includes depositing a varnish over the first and second leads.
13. The method of claim 12, further comprising formulating the anti-paint with at least one of: acrylic, silicone, polyurethane, epoxy, and alkyd resins.
14. A method of forming a Metal Oxide Varistor (MOV), comprising:
providing a varistor body comprising a first side and a second side opposite the first side;
forming a metallization layer along a first side or a second side of the varistor body;
soldering a first lead to the varistor body along the first side and connecting a second lead to the varistor body along the second side;
forming an insulating coating over the first and second sides of the varistor body, including over the first lead, the second lead, and the metallization layer; and
an epoxy coating is formed over the insulating coating.
15. The method of claim 14, wherein forming the insulating coating comprises: conformally depositing the insulating coating over the varistor body, the first lead, and the second lead, and wherein forming the epoxy coating comprises: the epoxy coating is conformally deposited over the insulating coating.
16. The method of claim 14, further comprising: a metallization layer is provided along at least one of the first and second sides of the varistor body, wherein the insulating coating is formed directly on top of the metallization layer.
17. The method of claim 14, wherein forming the metallization layer comprises: silver is deposited along at least one of the first and second sides of the varistor body.
18. The method of claim 14, wherein forming the insulating coating comprises: depositing a three-way paint over the first and second sides of the varistor body, including over the first and second leads.
19. The method of claim 18, further comprising formulating the tri-proof paint with at least one of: acrylic, silicone, polyurethane, epoxy, and alkyd resins.
20. A method according to claim 18, wherein the three-proofing lacquer is applied over the varistor body by using one of: brushing, spraying, automatic dipping, and selective coating, and wherein the three-way paint cures within a predetermined period of time prior to depositing the epoxy coating.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210254194.2A CN116798717A (en) | 2022-03-15 | 2022-03-15 | Coating of metal oxide varistors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210254194.2A CN116798717A (en) | 2022-03-15 | 2022-03-15 | Coating of metal oxide varistors |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116798717A true CN116798717A (en) | 2023-09-22 |
Family
ID=88048455
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210254194.2A Pending CN116798717A (en) | 2022-03-15 | 2022-03-15 | Coating of metal oxide varistors |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116798717A (en) |
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2022
- 2022-03-15 CN CN202210254194.2A patent/CN116798717A/en active Pending
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