Capacitor cell and stacked capacitor

Abstract

The application provides a capacitor unit and a laminated capacitor. The capacitor unit comprises a cathode substrate and an anode substrate arranged in layers. The anode substrate is rectangular, and an anode tab is arranged on one side of the anode substrate. The two corners of the side of the anode substrate on which the anode tab is arranged are smooth free curves. The two corners of the side of the anode substrate opposite to the anode tab are both beveled. Therefore, the capacitor unit can improve the reliability of the laminated capacitor.

Description

Technical Field

[0001] This application relates to the field of capacitors, specifically to a single capacitor and a stacked capacitor. Background Technology

[0002] With the development of the intelligent industry, new requirements have emerged for multilayer capacitors. For example, for AI servers, the computing power demand varies throughout the day, potentially leading to surges in demand and consequently, voltage spikes. The increased size of AI servers and their increased computing power also necessitate higher voltage withstand requirements for multilayer capacitors. Under high voltage, multilayer capacitors are prone to discharge, causing breakdown between the substrates and damaging the capacitors, thus compromising their reliability. Summary of the Invention

[0003] The purpose of this application is to improve the reliability of multilayer capacitors.

[0004] In a first aspect, this application provides a capacitor cell comprising a cathode substrate and an anode substrate stacked together; the anode substrate is rectangular, and at least one corner is a smooth free curve.

[0005] Optionally, an anode tab is provided on one side of the anode substrate, and both corners of the side of the anode substrate on which the anode tab is provided are smooth free curves. The two corners of the side of the anode substrate opposite to the anode tab are both folded.

[0006] Optionally, the four corners of the anode substrate are all smooth free curves.

[0007] Optionally, the anode substrate has a smooth, free-curved angle called an R-angle.

[0008] Optionally, an anode tab is provided on one side of the anode substrate; the radius of curvature of the anode substrate is smaller the farther the angle is from the anode tab.

[0009] Optionally, the angle corresponding to the R-angle between the cathode substrate and the anode substrate is also an R-angle.

[0010] Optionally, all four corners of the cathode substrate are folded corners.

[0011] Optionally, an anode tab is provided on one side of the anode substrate; the anode tab is plate-shaped, and the side of the anode tab is connected to the side of the anode substrate; the side of the anode substrate and the side of the anode tab are connected by an R-angle; and / or A cathode tab is provided on one side of the cathode substrate; the cathode tab is plate-shaped, and the side of the cathode tab is connected to the side of the cathode substrate; the side of the cathode substrate and the side of the cathode tab are connected by an R-angle.

[0012] Optionally, the radius of curvature of the R-angle between the anode substrate and the anode tab is greater than the radius of curvature of the R-angle of the anode substrate.

[0013] Secondly, this application also provides a stacked capacitor, including the aforementioned capacitor cell.

[0014] Based on the above technical solution, the corners of the anode substrate are smooth free curves, thus eliminating sharp angles and points. This prevents charge accumulation, which could lead to excessively high local electric field strength and cause point discharge. Furthermore, when the anode substrate is oxidized, the oxide layer oxidizes uniformly, preventing weak points at the corners and ensuring that the oxide layer does not break down at the edges, thereby improving the reliability of the capacitor. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this application. Those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0016] Figure 1 This is a schematic diagram of the anode substrate of a first embodiment of a capacitor cell provided in this application. Figure 2 This is a schematic diagram of the cathode substrate structure of a first embodiment of a capacitor cell provided in this application. Figure 3 This is a schematic diagram of the structure of a first embodiment of a capacitor cell provided in this application. Figure 4 This is a schematic diagram of the anode substrate of a second embodiment of the capacitor cell provided in this application. Figure 5 This is a schematic diagram of the anode substrate of a third embodiment of a capacitor cell provided in this application. Figure 6 This is a schematic diagram of the anode substrate of the fourth embodiment of the capacitor cell provided in this application. Figure 7 A schematic diagram of the cathode substrate of the fifth embodiment of the capacitor cell provided in this application; Figure 8 A schematic diagram of the structure of the stacked elements formed in the first embodiment of the capacitor cell provided in this application; Figure 9 This is an exploded structural diagram of a first embodiment of the stacked capacitor provided in this application. Figure 10 This is a schematic diagram of the assembly structure of a second embodiment of the stacked capacitor provided in this application.

[0017] The reference numerals in the attached figures are as follows: Stacked capacitor 102; 20. Sealing cap; 21. Support layer; 22. Inner film layer; 23. Outer film layer; 24. Anode lead-out terminal; 25. Cathode lead-out terminal; 26. Injection molded part; 30mm outer casing; 32mm opening; Elastic element 40; Stacked elements 10; Anode lead-out foil 16; Cathode lead-out foil 17; 18 pieces of adhesive tape were used to fix the tape. Capacitor unit 101; Anode substrate 11; Corner 111 of anode substrate; Edge 112 of anode substrate; 12 septum membranes; Cathode substrate 13; Corner 131 of cathode substrate; Edge 132 of cathode substrate; Anode tab 14; Cathode tab 15. Detailed Implementation

[0018] The following will refer to the appendices in this application. Figure 1 To be continued Figure 10 The technical solutions in this application are clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0019] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0020] The technical solution of this application is applicable to electrolytic capacitors, such as aluminum electrolytic capacitors. Among them, aluminum electrolytic capacitors are widely used in precision electronic equipment such as AI servers due to their characteristics of self-healing, large specific capacitance, aging resistance and high cost performance.

[0021] The term "layered" in multilayer capacitors is a concept relative to "winding" in wound capacitors. Specifically, it refers to the shape of the capacitor's constituent elements (or core). Wound capacitors have their constituent elements wound into a cylindrical shape, typically using only one cathode and one anode foil. In contrast, multilayer capacitors have their constituent elements consisting of a cathode substrate (in sheet form) and an anode substrate stacked together, usually with multiple cathode and anode substrates. It should be noted that in this application, "layered" is used to describe the shape of the capacitor's constituent elements and does not limit the type of capacitor; the capacitor can be solid, semi-solid, or liquid, etc.

[0022] Among them, multilayer capacitors are favored by engineers in the field of precision electronic equipment due to their lower ESR (Equivalent Series Resistance) and ESL (Equivalent Series Inductance). However, they are prone to discharge when subjected to high voltage, which can lead to breakdown between the substrates. Therefore, it is necessary to improve the reliability of multilayer capacitors.

[0023] To solve the above problems, please refer to... Figure 1 , Figure 2 and Figure 3 In a first aspect, this application provides a capacitor cell 101, including a cathode substrate 13 and an anode substrate 11 stacked together; the anode substrate is rectangular, and at least one corner is a smooth free curve.

[0024] A capacitor cell is the smallest unit in a capacitor that can produce capacitance. A capacitor cell is formed by stacking a cathode substrate and an anode substrate opposite each other (with sufficient spacing to avoid short circuits). In use, the anode substrate is connected to the anode of the external circuit, and the cathode substrate is connected to the cathode of the external circuit. When there is a potential difference between the anode and cathode, charge can be stored between the anode and cathode substrates, forming a capacitor.

[0025] When used in electrolytic capacitors, please refer to... Figure 8 A spacer 12 can also be provided between the cathode substrate and the anode substrate. The spacer is usually electrolytic paper, which can absorb the electrolyte. In this case, the cathode substrate plays the role of guiding the distribution of the electric field. The actual capacitor is formed between the anode substrate and the electrolyte. That is, the dielectric of the capacitor is the oxide layer on the surface of the anode substrate. Positive charges accumulate on the side of the oxide layer closer to the core material of the anode substrate, and negative charges accumulate on the side closer to the electrolyte.

[0026] Both the cathode and anode substrates are plate-shaped elements, and are rectangular in shape. Their sides, i.e., their edges, are shown in the reference diagram. Figure 1 The edge 112 of the anode substrate is marked; please refer to... Figure 2The edge 132 of the cathode substrate is marked. The intersection of two adjacent edges forms an angle; Figure 1 The corner 111 of the anode substrate is also marked in the text. Figure 2 The angle 131 of the cathode substrate is also marked in the image. Figure 3 In the middle, it refers to the state in which the cathode substrate and the anode substrate are stacked.

[0027] It can be seen that in Figure 1 and Figure 2 In the described embodiment, both the angles of the anode substrate and the cathode substrate are R-angles. Figure 4 In the embodiment shown, the largest x-axis and y-axis coordinate among the four corners of the figure is an irregular, smooth, free curve.

[0028] A smooth free curve is a curve without any sharp angles (or, in other words, a curve without any points where the curvature changes abruptly on either side). When determining whether the corner of the anode substrate is a smooth free curve, a reference surface can be set up, with the surface normal direction of the reference surface being the same as that of the anode substrate. The anode substrate is then projected onto this reference surface, and the outline of the projection is examined. If the outline corresponding to the corner of the anode substrate is a smooth free curve, then the corner is a free curve.

[0029] Because the corners of the anode substrate are free-form curves, there are no sharp angles even at the corners, thus avoiding surface structures with extremely small radii of curvature. This prevents tip discharge. Furthermore, when the anode substrate is used in electrolytic capacitors, an oxide film needs to be oxidized on the surface as a dielectric. The free-form curve shape also allows the oxide film to form uniformly at the corners, preventing the oxide film from being too thin at the corners and avoiding breakdown and discharge at the edges. Therefore, the technical solution of this application avoids anode substrate discharge and improves the reliability of capacitor operation.

[0030] Please refer to Figure 1 and Figure 5 Optionally, an anode tab 14 is provided on one side of the anode substrate, and the two corners of the side of the anode substrate where the anode tab is provided are both smooth free curves. The two corners of the sides of the anode substrate opposite to the anode tab are both folded.

[0031] The anode tab is the channel through which current enters the anode substrate; it is evident that the voltage is highest near the anode tab. Please refer to [reference needed]. Figure 5 As can be seen, the voltage gradually decreases with distance from the anode tab, i.e., along the negative y-axis in the figure, due to the resistance of the anode substrate. Therefore, the closer an angle is to the anode tab, the more important it is to prevent tip discharge.

[0032] For angles far from the anode tab, right angles can be used. For rectangular anode substrates, setting the bends to right angles increases the surface area of ​​the anode substrate, thereby increasing the capacitance that a single capacitor can generate.

[0033] It is evident that the above embodiments can balance the reliability and capacity of the capacitor, ensuring reliable operation while providing higher capacity.

[0034] Please refer to Figure 6 Optionally, the four corners of the anode substrate are all smooth free curves.

[0035] This configuration minimizes the risk of tip discharge at the bend, thereby further improving the reliability of the capacitor.

[0036] Please refer to Figure 6 Optionally, the anode substrate has a smooth, free-curved angle called the R angle.

[0037] The radius of curvature (R-angle) is also a type of smooth free curve, characterized by a relatively uniform radius of curvature throughout the curve. In reality, the probability of a point discharge is greatly influenced by the radius of curvature. Generally speaking, the larger the radius of curvature, the lower the probability of a point discharge; conversely, the smaller the radius of curvature (for example, at a mathematically ideal bend, the radius of curvature is infinitesimal), the higher the probability of a point discharge.

[0038] As can be seen, since the radius of curvature at each point on the R-angle is basically the same (basically or completely circular), there will be no position with small curvature (even if the radius of curvature of the free curve part is large, since the side that the free curve needs to connect is unchanged, there will still be parts with small curvature), thus avoiding weak points that are prone to tip discharge.

[0039] Please refer to Figure 6 Optionally, an anode tab is provided on one side of the anode substrate; the radius of curvature is smaller at angles farther from the anode substrate than at angles farther from the anode tab.

[0040] exist Figure 6 In the example shown, D1, D2, D3, and D4 are used to identify the distances from the anode tabs to the four corners. It can be seen that D1 < D2 < D3 < D4. At the same time, if R1, R2, R3, and R4 are used to represent the radii of curvature of the corners corresponding to D1, D2, D3, and D4, then R1 > R2 > R3 > R4.

[0041] As mentioned above, the farther the angle is from the anode tab, the lower the voltage it withstands due to the resistance of the anode substrate; a smaller radius of curvature also helps to increase the surface area of ​​the anode substrate, thereby increasing the capacitance. Therefore, making the radius of curvature smaller for the angle of the anode substrate farther from the anode tab can balance the reliability and capacitance of the capacitor, ensuring reliable operation while having higher capacitance.

[0042] It should be noted that there may be two angles that are exactly the same distance from the anode tab. In this case, the radii of curvature of the two angles can be equal.

[0043] Please refer to Figure 2 Optionally, the angle corresponding to the R-angle between the cathode substrate and the anode substrate is also the R-angle.

[0044] When applied to ceramic capacitors and film capacitors, the charge is also stored in the cathode substrate. In this case, setting the corners of the cathode substrate to R-angle can also prevent tip discharge. It should be noted that the setting method can refer to the setting method of R-angle of the anode substrate described above.

[0045] When applied to aluminum or tantalum electrolytic capacitors, the cathode substrate is not used to store the capacitor, but it can guide the electric field distribution. This can guide the electric field intensity at the R-corner of the anode substrate to be evenly distributed, avoiding excessive local field strength that could cause discharge.

[0046] Please refer to Figure 7 Optionally, all four corners of the cathode substrate are folded.

[0047] When applied to aluminum or tantalum electrolytic capacitors, capacitance is formed only in the portion of the anode substrate whose projection onto the cathode substrate lies within the cathode substrate; the portion exposed to the cathode substrate produces virtually no capacitance. Therefore, the four corners of the cathode substrate are angled to increase its area, allowing it to cover the anode substrate as much as possible and thus maximizing capacitance.

[0048] Please refer to Figure 1 Optionally, an anode tab is provided on one side of the anode substrate; the anode tab is plate-shaped, and the side of the anode tab is connected to the side of the anode substrate; the side of the anode substrate and the side of the anode tab are connected by an R-angle.

[0049] Figure 1 In the diagram, the R-angle used for connection is marked by Z. It can be seen that the R-angle setting avoids the connection between the anode tab and the anode substrate by bending, thus avoiding stress concentration and preventing the connection position between the anode tab and the anode substrate from cracking. This also avoids discharge caused by cracking (although no sharp point is generated, the oxide film will still crack, causing discharge).

[0050] Please refer to Figure 2 Optionally, a cathode tab 15 is provided on one side of the cathode substrate; the cathode tab is plate-shaped, and the side of the cathode tab is connected to the side of the cathode substrate; the side of the cathode substrate and the side of the cathode tab are connected by an R-angle.

[0051] Figure 2In the diagram, the R-angle used for connection is marked by Z. It can be seen that the R-angle setting avoids the connection between the cathode tab and the cathode substrate by bending, thus avoiding stress concentration and cracking at the connection position between the cathode tab and the cathode substrate. This also avoids discharge caused by cracking (for embodiments where the cathode substrate stores charge) or capacity reduction caused by abnormal electric field distribution (for embodiments where the cathode substrate guides the electric field distribution).

[0052] Please refer to Figure 1 and Figure 2 Optionally, the radius of curvature of the R-angle between the anode substrate and the anode tab is greater than the radius of curvature of the R-angle of the anode substrate.

[0053] The radius (R) between the anode substrate and the anode tab is the R-angle mentioned above, designed to prevent stress concentration and cracking. The radius (R) of the anode substrate refers to the radius (R) at the four corners of the anode substrate. The radius (R) at the four corners of the anode substrate needs to take into account the area of ​​the anode substrate. The radius (R) between the anode substrate and the anode tab does not affect the surface area of ​​the anode substrate, so it can be set as large as possible.

[0054] It is evident that by making the radius of curvature of the R-angle between the anode substrate and the anode tab greater than the radius of curvature of the R-angle of the anode substrate, both reliability and capacity can be balanced, thus avoiding cracking and improving capacity.

[0055] Please refer to Figure 9 and Figure 10 Secondly, this application also provides a stacked capacitor 102, including the aforementioned capacitor cell.

[0056] Please refer to Figure 9 A multilayer capacitor can have the structure shown in the figure: The stacked capacitor may include a housing 30, which has an opening 32 that connects to an accommodating space inside the housing, where the stacked element 10 can be placed.

[0057] It should be noted that the stacked element can be formed from a single capacitor cell or from multiple capacitor cells stacked together. The stacked element can be fixed by wrapping the outer periphery with the fixing tape 18, or it can be fixed by placing it directly inside the outer casing.

[0058] The opening can be closed by the sealing cap 20. The sealing cap may include a support layer 21, an outer membrane layer 23, and an inner membrane layer 22. The outer membrane layer and the inner membrane layer are respectively attached to both sides of the support layer. The outer membrane layer is used for external insulation, and the inner membrane layer is used for insulation with the stacked elements.

[0059] The sealing cap may also include an anode lead-out terminal 24 and a cathode lead-out terminal 25, both of which are disposed in the support layer. The anode lead-out terminal is electrically connected to the anode of the stacked element through an anode lead-out foil strip 16, and the cathode lead-out terminal is electrically connected to the cathode of the stacked element through a cathode lead-out foil strip 17.

[0060] Both the support layer and the outer shell can be conductors and can be electrically connected to each other. The cathode lead-out terminal can also be directly electrically connected to the support layer, thus forming an outer shell and support layer connected to a low potential, providing better electromagnetic shielding for the stacked element and preventing external radiation from affecting the operation of the stacked element. At this time, an injection-molded part 26 can also be provided to isolate the anode lead-out terminal and the support layer, preventing short circuits between the anode lead-out terminal and the support layer.

[0061] An elastic element 40 can also be provided between the sealing cap and the stacked element. The elastic element is interference-fitted with the sealing cap and the stacked element, thereby pressing the stacked element tightly inside the shell, preventing the stacked element from shaking, and ensuring the stable operation of the stacked element.

[0062] It should be noted that the capacitor cell and the stacked capacitor in the embodiments of this application are different subjects under the same inventive concept. Features not described in detail in each embodiment can be referred to in the description of other embodiments. Under the premise of no conflict, the embodiments can be combined arbitrarily, and the combined solution is also within the protection scope of the embodiments of this application.

[0063] It should be noted that the term "multiple" in this application generally refers to two or more. Furthermore, directional terms used in the embodiments of this application, such as "up," "down," "front," "back," "left," "right," "inner," "outer," and "side," are only for reference to the accompanying drawings. Therefore, the directional terms used are for illustrating and understanding the embodiments of this application, and not for limiting the embodiments of this application. The term "connection" in this application generally refers to a direct connection between two components or an indirect connection achieved through other components. In the various figures, structurally similar units are represented by the same reference numerals. For clarity, the various parts in the figures are not drawn to scale. Additionally, some related parts may not be shown in the figures.

[0064] It should be understood that in the description of this application, terms such as "first" and "second" are used only to distinguish similar objects and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0065] It is understood that those skilled in the art can combine various implementation methods in the above embodiments under the guidance of the above examples to obtain technical solutions with multiple implementation methods. The above descriptions are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

[0066] The foregoing has provided a detailed description of the single capacitor and the stacked capacitor provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of aiding understanding this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there may be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A single capacitor cell, characterized in that, include: A cathode substrate and an anode substrate stacked together; The anode substrate is rectangular, and an anode tab is provided on one side of the anode substrate. The two corners of the side of the anode substrate where the anode tab is provided are both smooth free curves; the two corners of the side of the anode substrate opposite to the anode tab are both angled.

2. The capacitor cell according to claim 1, characterized in that, The four corners of the anode substrate are all smooth free curves.

3. The capacitor cell according to claim 1, characterized in that, The anode substrate has a smooth, free-curve shape with an angle called R angle.

4. The capacitor cell according to claim 3, characterized in that, An anode tab is provided on one side of the anode substrate; the radius of curvature of the anode substrate is smaller the farther the angle is from the anode tab.

5. The capacitor cell according to claim 3, characterized in that, The angle corresponding to the R-angle of the cathode substrate and the anode substrate is also an R-angle.

6. The capacitor cell according to claim 3, characterized in that, The cathode substrate has four folded corners.

7. The capacitor cell according to claim 3, characterized in that, An anode tab is provided on one side of the anode substrate; the anode tab is plate-shaped, and its side is connected to the side of the anode substrate; the side of the anode substrate and the side of the anode tab are connected by an R-angle; and / or A cathode tab is provided on one side of the cathode substrate; the cathode tab is plate-shaped, and the side of the cathode tab is connected to the side of the cathode substrate; the side of the cathode substrate and the side of the cathode tab are connected by an R-angle.

8. The capacitor cell according to claim 7, characterized in that, The radius of curvature of the R-angle between the anode substrate and the anode tab is greater than the radius of curvature of the R-angle of the anode substrate.

9. The capacitor cell according to claim 1, characterized in that, A spacer membrane is provided between the anode substrate and the anode tab.

10. A multilayer capacitor, characterized in that, Includes the capacitor cell as described in any one of claims 1-9.

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