Novel soaking aluminum electrolytic capacitor

Abstract

The utility model relates to a novel soaking aluminum electrolytic capacitor, which comprises a shell, a core and a sealing cover, the device is characterized in that the shell is provided with an inner cavity; the core is packaged in the inner cavity of the shell by the sealing cover; the core is formed by sequentially laminating and winding a positive foil, electrolytic paper and a negative foil; the negative foil on one side of the bottom of the core is provided with a negative foil extension part; the part, exceeding the bottom edge of the positive foil, of the negative foil extending part is in contact with the bottom of the inner cavity of the shell. The problems that in the prior art, an aluminum electrolytic capacitor is large in low-temperature capacitance attenuation and low-temperature slurry explosion exist are solved. The phenomenon of local overheating breakdown in the core is avoided, and the ripple resistance of the aluminum electrolytic capacitor is improved. The problems of large low-temperature capacitance attenuation and low-temperature slurry explosion of the aluminum electrolytic capacitor are solved, particularly, charging piles, new energy, vehicle-mounted equipment, 5G communication equipment and other equipment suitable for being used in extremely cold low temperature are guaranteed, the stability of the aluminum electrolytic capacitor is improved, and the low-temperature application field of the aluminum electrolytic capacitor is further expanded.

Description

Technical Field

[0001] The utility model relates to the technical field of aluminum electrolytic capacitors, in particular to a novel heat-averaging aluminum electrolytic capacitor. Background Art

[0002] With the development of new energy industries such as charging piles, photovoltaics, and energy storage, the power density of power devices is getting higher and higher, and the energy density of aluminum electrolytic capacitors used in conjunction with them is also required to be continuously improved. At present, the core package of aluminum electrolytic capacitors is generally composed of positive and negative aluminum foils and electrolytic paper stacking and winding, in which the positive foil and the negative foil are the same width and smaller than the width of the electrolytic paper. With the rapid development of new energy and 5G fields, capacitors are required to maximize their capacity within a certain volume to meet the application of small volume and high power, and aluminum electrolytic capacitors are required to have strong low temperature characteristics and strong ripple resistance. With the rapid development of new energy and 5G fields, new energy and 5G equipment are bound to be widely used in extremely cold environments. In low temperature environments, the capacity of aluminum electrolytic capacitors will decay, and the impedance of aluminum electrolytic capacitors will increase, causing a series of low temperature failure problems of aluminum electrolytic capacitors. These problems will constrain the use of new energy and 5G equipment in low temperature environments. This requires that the low temperature characteristics and ripple resistance of electrolytic capacitors must be improved, so it is imperative to improve the low temperature characteristics of capacitors and enhance the temperature resistance of capacitors. Utility Model Content

[0003] Based on this, it is necessary to provide a new type of heat-averaged aluminum electrolytic capacitor to solve the problems of large low-temperature capacitance decay and low-temperature bursting of aluminum electrolytic capacitors in the prior art.

[0004] The utility model solves the technical problem by adopting the following technical solutions:

[0005] A novel heat-averaging aluminum electrolytic capacitor comprises a shell, a core and a sealing cover; the characteristics are as follows: the shell is provided with an inner cavity; the sealing cover encapsulates the core in the inner cavity of the shell; the core is formed by stacking and winding a positive foil, an electrolytic paper and a negative foil in sequence; a negative foil extension is provided on the negative foil at one side of the bottom of the core; the part of the negative foil extension that exceeds the bottom edge of the positive foil contacts the bottom of the inner cavity of the shell; the longitudinal width of the negative foil in the core is greater than the longitudinal width of the positive foil; the longitudinal top of the positive foil is flush with the longitudinal top of the negative foil; the longitudinal bottom of the negative foil exceeds the longitudinal bottom edge of the positive foil; wherein the exceeding part is the negative foil extension.

[0006] Preferably, the bottom end of the negative foil extension portion contacts the upper end surface of the heat conducting plate, and the bottom of the heat conducting plate contacts the bottom of the inner cavity of the housing.

[0007] Preferably, the outer surface of the negative foil extension portion is coated with a thermally conductive coating; the thermally conductive coating at the bottom of the negative foil extension portion is in contact with the bottom of the inner cavity of the housing.

[0008] Preferably, a heat transfer member is sleeved on the outside of the core; the heat transfer member includes a base in contact with the bottom of the negative foil extension portion and an arm in contact with the side wall of the core.

[0009] The advantages and positive effects of the utility model are: the utility model is a new type of heat-averaged aluminum electrolytic capacitor, which is used to solve the problems of large low-temperature capacitance decay and low-temperature burst of aluminum electrolytic capacitors in the prior art. Compared with the prior art, the utility model has the following advantages:

[0010] The utility model transfers the heat inside the core to the inner cavity of the aluminum electrolytic capacitor through negative foil heat conduction. In a low-temperature environment, the temperature outside the core is compensated to achieve a temperature balance effect, so that the capacity of the aluminum electrolytic capacitor does not decay when used in a low-temperature environment, and the original characteristics of the capacitor are maintained. On the other hand, the heat inside the core is transferred outward to achieve a temperature balance effect, avoiding the occurrence of local overheating and breakdown in the core, and improving the ripple resistance of the aluminum electrolytic capacitor. The problems of large low-temperature capacity decay and low-temperature bursting of aluminum electrolytic capacitors are improved, especially the charging piles, new energy, vehicle-mounted, 5G communications and other equipment suitable for use in extremely cold and low temperatures are guaranteed, its stability is improved, and the low-temperature application field of aluminum electrolytic capacitors is further expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0012] Figure 1 It is a three-dimensional structural schematic diagram of the utility model.

[0013] Figure 2 It is a schematic diagram of the three-dimensional structure of the core of the utility model.

[0014] Figure 3 It is a cross-sectional schematic diagram of the first embodiment of the utility model.

[0015] Figure 4 It is a cross-sectional schematic diagram of the second embodiment of the present utility model.

[0016] Figure 5 It is a cross-sectional schematic diagram of the third embodiment of the present utility model.

[0017] Figure 6 It is a cross-sectional schematic diagram of the fourth embodiment of the present utility model.

[0018] Figure 7It is a schematic diagram of the core structure of the utility model.

[0019] Figure 8 It is a schematic diagram of the cross section of the negative foil of the utility model.

[0020] Fig. 9 It is a schematic diagram of the negative foil extension part of the utility model.

[0021] Explanation of the accompanying drawings: 1. outer shell; 2. core; 3. sealing cover; 4. positive lead; 5. negative lead; 6. positive pin; 7. negative pin; 8. thermal conductive sheet; 9. thermal conductive coating; 10. thermal conductive adhesive; 11. heat transfer member; 101. inner cavity; 201. positive foil; 202. negative foil; 203. electrolytic paper; 501. nailing part; 111. base; 112. arm; 113. cavity; 2021. negative foil extension. DETAILED DESCRIPTION

[0022] The embodiments of the utility model are further described in detail in conjunction with the accompanying drawings: The technical solutions in the embodiments of the utility model are clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means a limitation on the utility model and its application or use. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] In the description of the present invention, it should be understood that the terms "length", "up", "down", "left", "right", "vertical", "horizontal", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0024] In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0025] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "fixed", "provided with", etc. should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] like Figure 1 As shown, the aluminum electrolytic capacitor includes a shell 1, a core 2, and a sealing cover 3; the inner cavity of the shell 1; the sealing cover 3 encapsulates the core 2 in the inner cavity of the shell 1; the core 2 is formed by stacking and winding a positive foil 201, an electrolytic paper 203, and a negative foil 202 in sequence.

[0027] Specifically, the aluminum electrolytic capacitor of this embodiment includes a guide pin type aluminum electrolytic capacitor, a horn type aluminum electrolytic capacitor, and a bolt type aluminum electrolytic capacitor. The core 2 of the aluminum electrolytic capacitor is composed of a chemically formed foil, which is divided into a positive foil 201 and a negative foil 202. The negative foil 202 is subjected to chemical etching to form holes on the surface. After repeated chemical forming processes, an oxide film is formed on the surface of the holes to obtain a chemically formed foil. The positive foil 201 and the negative foil 202 are respectively nailed to the positive lead 4 and the negative lead 5, and the nailing part 501 is formed at the nailing part. The positive foil 201, the electrolytic paper 203, and the negative foil 202 are stacked in sequence and then wound to form a columnar core 2. The core 2 is impregnated with electrolyte so that the electrolyte is adsorbed in the core 2. The core 2 impregnated with electrolyte is assembled and installed in the inner cavity 101 of the shell 1, and the opening of the shell 1 is sealed with a sealing cover 3. After aging, the oxide film damaged at the nailing part of the positive and negative foils is repaired to obtain an aluminum electrolytic capacitor. When the aluminum electrolytic capacitor is working, the core 2 has impedance, which will generate heat. Under the ripple current, the negative foil 202 and the lead pin will generate local heat, causing the local temperature to be too high, and in severe cases, overheating and breakdown will occur, affecting the stability of the aluminum electrolytic capacitor.

[0028] Example 1

[0029] like Figure 3 , 7 As shown, the negative foil 202 at one side of the bottom of the core 2 is provided with a negative foil extension 2021 ; the portion of the negative foil extension 2021 that exceeds the bottom edge of the positive foil 201 contacts the bottom of the inner cavity of the shell 1 .

[0030] Specifically, in this embodiment, the width of the electrolytic paper 203 is larger than the width of the positive foil 201, so that the electrolytic paper 203 can completely cover the positive foil 201 when winding, and the upper and lower edges of the positive foil 201 will not be exposed from the edge of the electrolytic paper 203, playing a role of insulation and isolation. After the positive foil 201 is stacked with the negative foil 202 and the electrolytic paper 203, the part of the bottom of the negative foil 202 that exceeds the bottom of the positive foil 201 is the negative foil extension 2021, wherein the negative foil extension 2021 and the negative foil 202 are the same body. In some embodiments, the negative foil extension 2021 can be an aluminum foil with no oxide film on the surface, that is, a plain foil, so that the relative area of ​​the positive foil 201 and the negative foil 202 in the entire core 2 is the same, and the plain foil serves as an aluminum base for heat conduction, and the negative foil extension 2021 is welded together with the contact point at the bottom of the inner cavity of the shell 1. The negative foil extension 2021 and the bottom edge are in contact with the bottom of the inner cavity of the shell 1, which improves the heat dissipation effect, so that the local heat at the nailing of the negative foil 202 can be quickly extracted. The negative foil extension 2021 is in contact with the bottom of the inner cavity of the shell 1, so that the heat in the core 2 is quickly transferred to the inner cavity of the aluminum electrolytic capacitor, which plays a role in heat transfer and thermal balance. Especially in low-temperature environments, the low-temperature attenuation of aluminum electrolytic capacitors is particularly serious. In this embodiment, the heat inside the core 2 is conducted outward through the negative foil extension 2021, and the local heat in the aluminum electrolytic capacitor core 2 is used to make up for the temperature difference in the inner cavity of the aluminum electrolytic capacitor due to low-temperature attenuation, which plays a role in thermal balance. The heat of the aluminum electrolytic capacitor itself is used to supplement the low-temperature area of ​​the inner cavity, so that the temperature of the inner cavity of the aluminum electrolytic capacitor can be kept balanced, and the electrolyte can maintain its original characteristics, so that the capacity of the aluminum electrolytic capacitor does not decay when used in a low-temperature environment.

[0031] like Figure 3 As shown, the longitudinal width of the negative foil 202 in the core 2 is greater than the longitudinal width of the positive foil 201; the longitudinal top of the positive foil 201 is flush with the longitudinal top of the negative foil 202; the longitudinal bottom of the negative foil 202 exceeds the longitudinal bottom edge of the positive foil 201; the exceeding part is the negative foil extension part 2021.

[0032] Specifically, after the positive foil 201 and the negative foil 202 are cut, their edges are flush, wherein the longitudinal width of the negative foil 202 is wider than that of the positive foil 201. When stacked, the upper end surfaces of the positive foil 201 and the negative foil 202 are flush, and an electrolytic paper 203 is arranged between the positive foil 201 and the negative foil 202, and the electrolytic paper 203 separates the positive foil 201 and the negative foil 202. Since the longitudinal width of the negative foil 202 is wider than that of the positive foil 201, after the positive foil 201 and the negative foil 202 are stacked, the upper end surfaces of the positive foil 201 and the negative foil 202 are flush, and a height difference is formed between the bottom end surfaces of the positive foil 201 and the negative foil 202, and the bottom end surface of the negative foil 202 exceeds the bottom end surface of the positive foil 201. Among them, the part of the negative foil 202 that exceeds the bottom end surface of the positive foil 201 is the negative foil extension 2021.

[0033] Example 2

[0034] like Figure 4 As shown, the longitudinal width of the negative foil 202 in the core 2 is greater than the longitudinal width of the positive foil 201; the longitudinal top of the positive foil 201 is flush with the longitudinal top of the negative foil 202; the longitudinal bottom of the negative foil 202 exceeds the longitudinal bottom edge of the positive foil 201; wherein the exceeding part is the negative foil extension 2021. The bottom end of the negative foil extension 2021 contacts the upper end surface of the heat conducting sheet 8, and the bottom of the heat conducting sheet 8 contacts the bottom of the inner cavity of the housing 1.

[0035] Specifically, when the aluminum electrolytic capacitor is assembled and installed, a heat conductive sheet 8 is arranged at the bottom of the inner cavity of the shell 1, wherein the shape of the heat conductive sheet 8 is not limited, and can be one of square, round, and polygonal. The heat conductive sheet 8 is made of a material with a high thermal conductivity coefficient, and can be a heat conductive ceramic or a heat conductive body coated with a heat conductive coating. Among them, the heat conductive coating is selected from at least one of a graphene heat conductive film, a graphite heat conductive film, and a boron nitride heat conductive film.

[0036] The bottom end of the negative foil extension 2021 contacts the upper end surface of the thermal conductive sheet 8, and the bottom of the thermal conductive sheet 8 contacts the bottom of the inner cavity of the shell 1. When ordinary aluminum electrolytic capacitors work in a cold and low-temperature environment, their impedance ESR will increase. Under ripple current, the nailing portion 501 where the negative foil 202 is nailed to the negative lead 5 will heat up first. When the local heat reaches a certain value, overheating breakdown will occur, causing the entire capacitor to burst and fail. In this embodiment, the bottom end of the negative foil extension 2021 is set to contact the upper end surface of the thermal conductive sheet 8, and the bottom of the thermal conductive sheet 8 is in contact with the bottom of the inner cavity of the shell 1. When the aluminum electrolytic capacitor works in a low-temperature environment, its impedance ESR will increase. Under ripple current, the negative foil 202 in the core will heat up first. More specifically, the nailing portion 501 where the negative foil 202 is nailed to the negative lead 5 will heat up first. This heating phenomenon is local heating. When the temperature exceeds the maximum tolerance temperature, there will be a risk of overheating breakdown. In this embodiment, the negative foil extension 2021 conducts the negative foil 202 and the heat to the outside, and the negative foil extension 2021 transfers the heat to the thermal conductive sheet 8. The outer peripheral side of the thermal conductive sheet 8 is exposed in the inner cavity of the aluminum electrolytic capacitor shell 1 and is in direct contact with the electrolyte. The heat in the core is transferred from the negative foil 202 to the thermal conductive sheet 8, and then the thermal conductive sheet 8 transfers the heat to the electrolyte, the shell 1 and the entire inner cavity of the shell 1, so that the temperature in the inner cavity of the shell 1 is supplemented, and the electrolyte is supplemented at low temperatures. The electrolyte restores its original characteristics at room temperature. At low temperatures, the temperature in the inner cavity of the shell 1 is supplemented by the heat from the core 2, achieving the effect of temperature balance, so that the aluminum electrolytic capacitor will not cause low-temperature capacity attenuation even if it is used in a low-temperature environment. This design, on the one hand, plays a role in heat dissipation and solves the problem of bursting caused by the increase of low-temperature impedance ESR. On the other hand, through the transfer of temperature, it plays a role in temperature supplementation and solves the problem of capacity attenuation of low-temperature capacitors.

[0037] Example 3

[0038] like Figure 5 As shown, a thermal conductive adhesive 10 is coated between the outer surface of the negative foil extension 2021 and the bottom of the shell 1. When the heat inside the core 2 is transferred to the negative foil extension 2021, the heat in the negative foil extension 2021 is more easily transferred to the shell 1 under the cover of the thermal conductive adhesive 10. At the same time, the thermal conductive adhesive 10 is exposed in the inner cavity of the shell 1, which improves the heat radiation and the temperature rise rate of the electrolyte in a low temperature environment, thereby achieving a rapid temperature supplement effect.

[0039] The heat in the core 2 is transferred from the negative foil 202 to the thermally conductive adhesive 10, and then the thermally conductive adhesive 10 transfers the heat to the electrolyte, the shell 1 and the entire inner cavity of the shell 1, so that the temperature in the inner cavity of the shell 1 is supplemented, and the electrolyte is supplemented at low temperatures, and the electrolyte restores its original characteristics at room temperature. At low temperatures, the temperature in the inner cavity of the shell 1 is supplemented by the heat from the core, achieving a temperature balance, so that the aluminum electrolytic capacitor will not cause low-temperature capacity attenuation even if used in a low-temperature environment. This design, on the one hand, plays a role in heat dissipation and solves the problem of bursting caused by increased low-temperature impedance ESR. On the other hand, through the transfer of temperature, it plays a role in temperature supplementation and solves the problem of capacity attenuation of low-temperature capacitors.

[0040] Example 4

[0041] like Figure 6 As shown, the core 2 is externally sleeved with a heat transfer member 11 ; the heat transfer member 11 includes a base 111 in contact with the bottom of the negative foil extension 2021 , and an arm 112 in contact with the side wall of the core 2 , and the core 2 is disposed in a cavity 113 .

[0042] The difference from Example 1 is that when the aluminum electrolytic capacitor is assembled and packaged, a heat transfer member 11 is set at the bottom of the core, and the bottom of the negative foil extension 2021 contacts the base 111, so that the heat inside the core 2 is directly transferred to the heat transfer member 11, and the arm 112 contacting the side wall of the core 2 is more quickly and effectively transferred to the inner cavity of the shell 1 and the electrolyte, further improving the heat transfer efficiency. When the aluminum electrolytic capacitor is used in a low temperature environment, such as in an extremely cold environment below -20 degrees Celsius, the electrolyte in the inner cavity of the shell 1 is almost in a condensed and inactivated state, losing its original characteristics, causing the aluminum electrolytic capacitor to seriously decay in capacity.

[0043] The heat in the core 2 is transferred to the heat transfer member 11 by the negative foil 202, and then the arm 112 and the cavity 113 of the heat transfer member 11 transfer the heat to the electrolyte, the shell 1 and the inner cavity of the entire shell 1, so that the temperature in the inner cavity of the shell 1 is supplemented, and the electrolyte is supplemented at low temperatures, and the electrolyte recovers its original characteristics at room temperature. At low temperatures, the temperature in the inner cavity of the shell 1 is supplemented by the heat from the core, achieving a temperature balance, so that the aluminum electrolytic capacitor will not cause low-temperature capacity attenuation even if it is used in a low-temperature environment. This design, on the one hand, plays a role in heat dissipation and solves the problem of bursting caused by increased low-temperature impedance ESR. On the other hand, through the transfer of temperature, it plays a role in temperature supplementation and solves the problem of capacity attenuation of low-temperature capacitors.

[0044] Example 5

[0045] like Figure 8-9 As shown, the outer surface of the negative foil extension 2021 is coated with a thermal conductive coating 9; the thermal conductive coating 9 at the bottom of the negative foil extension 2021 contacts the bottom of the inner cavity of the shell 1. The thermal conductive coating is selected from at least one of boron nitride powder, aluminum nitride powder, silicon carbide powder, graphene powder, and graphite powder. The thermal conductive filler has a strong thermal conductivity. The outer surface of the negative foil extension 2021 is coated with a thermal conductive coating 9, which improves the thermal conductivity efficiency, so that the heat in the core 2 is transferred to the thermal conductive coating 9 on the outer surface of the negative foil extension 2021 through the negative foil 202.

[0046] The heat is then transferred by the thermal conductive coating 9 to the electrolyte, the shell 1 and the inner cavity of the entire shell 1, so that the temperature in the inner cavity of the shell 1 is supplemented, and the electrolyte is supplemented at low temperatures. The electrolyte restores its original characteristics at room temperature. At low temperatures, the temperature in the inner cavity of the shell 1 is supplemented by the heat from the core, achieving a temperature balance, so that the aluminum electrolytic capacitor will not cause low-temperature capacity attenuation even if used in a low-temperature environment. This design, on the one hand, has a heat dissipation effect and solves the problem of bursting caused by increased low-temperature impedance ESR. On the other hand, through the transfer of temperature and the use of its own heat transfer, it plays a temperature supplement role and solves the problem of capacity attenuation of low-temperature capacitors.

[0047] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention is not limited to the embodiments described in the specific implementation manner. Any other implementation manners derived by those skilled in the art based on the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A novel heat-averaging aluminum electrolytic capacitor, comprising a housing (1), a core (2), and a sealing cover (3); characterized in that: The shell (1) is provided with an inner cavity; the sealing cover (3) seals the core (2) in the inner cavity of the shell (1); the core (2) is formed by stacking and winding a positive foil (201), an electrolytic paper (203), and a negative foil (202) in sequence; the negative foil (202) on one side of the bottom of the core (2) is provided with a negative foil extension portion (2021); the portion of the negative foil extension portion (2021) that exceeds the bottom edge of the positive foil (201) contacts the bottom of the inner cavity of the shell (1); the longitudinal width of the negative foil (202) in the core (2) is greater than the longitudinal width of the positive foil (201); the longitudinal top of the positive foil (201) is flush with the longitudinal top of the negative foil (202); the longitudinal bottom of the negative foil (202) exceeds the longitudinal bottom edge of the positive foil (201); wherein the exceeding portion is the negative foil extension portion (2021).

2. A novel heat-saturated aluminum electrolytic capacitor according to claim 1, characterized in that: The bottom end of the negative foil extension portion (2021) contacts the upper end surface of the heat conducting plate (8), and the bottom of the heat conducting plate (8) contacts the bottom of the inner cavity of the housing (1).

3. A novel heat-saturated aluminum electrolytic capacitor according to claim 1, characterized in that: The outer surface of the negative foil extension part (2021) is coated with a thermally conductive coating (9); the thermally conductive coating (9) at the bottom of the negative foil extension part (2021) is in contact with the bottom of the inner cavity of the housing (1).

4. A novel heat-saturated aluminum electrolytic capacitor according to claim 1, characterized in that: The core (2) is externally sleeved with a heat transfer member (11); the heat transfer member (11) comprises a base (111) in contact with the bottom of the negative foil extension portion (2021) and an arm portion (112) in contact with a side wall of the core (2).

Images