Capacitor capable of preventing degradation of conductive polymer
By introducing an insulating layer into the capacitor to isolate the lead foil from the end face of the cell, the problem of degradation of conductive polymers due to electrochemical reactions is solved, thereby improving the reliability and performance of the capacitor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA ZHENHUA GRP XINYUN ELECTRONICS COMP ANDDEV CO LTD
- Filing Date
- 2025-04-27
- Publication Date
- 2026-04-28
AI Technical Summary
Conductive polymers degrade due to electrochemical reactions in aluminum electrolytic capacitors with solder pin covers, resulting in reduced capacitor capacity and increased losses.
An insulating layer is placed between the capacitor core and the cover plate to isolate the lead foil from the end face of the core and prevent direct contact between the conductive polymer. An insulating pad made of polytetrafluoroethylene is used to form an insulating shield.
It effectively prevents the degradation of conductive polymers, improves the reliability of capacitors, and reduces capacity decay and loss.
Smart Images
Figure CN224177226U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of capacitor technology, and particularly relates to a capacitor that prevents the degradation of conductive polymers. Background Technology
[0002] The solder pin cover type conductive polymer aluminum electrolytic capacitor is a large-capacity aluminum capacitor. During assembly, the capacitor core needs to be encapsulated in an aluminum casing. The distance between the cover plate and the capacitor core is reduced to a certain height to ensure the final external dimensions of the capacitor. However, during the encapsulation process, the rivets on the cover plate and the lead foil will exert a slight pressure on the capacitor core. A schematic diagram of the cover plate and core position during assembly is shown below. Figure 5 As shown. During the subsequent long-term electrical aging process under high temperature and energized conditions, the conductive polymer with PEDOT:PSS as the main component on the capacitor core end face undergoes anionic degradation of the PSS groups in the conductive polymer under the influence of voltage. - Electrochemical reactions occur at the positive electrode contact point, involving substances such as polystyrene sulfonate anion. During the energizing process, the PSS chains in the conductive polymer at the positive electrode lead compression point separate and degrade from the PEDOT chains, forming an additional dielectric layer on the top of the cell. The conductive polymer at the contact point becomes an insulating material. Therefore, the localized decomposition of the conductive polymer on the capacitor core and the resulting insulating material reduce the conductivity at that point, leading to a decrease in capacitor capacitance and an increase in capacitor losses.
[0003] To reduce this abnormality in conductive polymer aluminum electrolytic capacitors with solder pin covers, the focus of research has been on preventing the degradation of the conductive polymer at the contact points between the lead foil, rivet points, and capacitor core. Utility Model Content
[0004] To solve the above-mentioned technical problems, this utility model provides a capacitor that prevents the degradation of conductive polymers.
[0005] This utility model is achieved through the following technical solution.
[0006] This utility model provides a capacitor for preventing degradation of conductive polymers, comprising a shell, a capacitor core, and a cover plate. The capacitor core is disposed inside the shell and has leads, a fixing strap, and an insulating layer disposed on it. The cover plate is connected to the shell and has leads disposed on it. The capacitor core is connected to the leads via the leads. The insulating layer is disposed between the capacitor core and the cover plate, and the leads penetrate through the insulating layer.
[0007] Preferably, the lead wire and the lead end are fastened together by rivets.
[0008] Preferably, the insulating layer is arranged in a circular sheet shape.
[0009] Preferably, the insulating layer is provided with through holes, and the lead wire passes through the through holes to penetrate the insulating layer.
[0010] Preferably, two through holes are provided on the insulating layer.
[0011] Preferably, the two through holes are set at an angle of 90° to 180° to the center point of the insulating layer.
[0012] The beneficial effects of this utility model are as follows:
[0013] This invention uses an insulating gasket to isolate the rivets and lead foil on the cover plate from the upper surface of the battery cell, forming an insulating shield. This prevents the lead foil from directly contacting the conductive polymer on the upper surface of the battery cell, thereby preventing the rivets and lead foil from degrading the conductive polymer on the core during the capacitor's operation and improving the reliability of the capacitor. Attached Figure Description
[0014] Figure 1 This is a schematic diagram of the structure of this utility model;
[0015] Figure 2 This is a schematic diagram of the structure of the insulating layer of this utility model;
[0016] Figure 3 This is a schematic diagram of the structure of the insulating layer of this utility model;
[0017] Figure 4 This is a schematic diagram of the structure in Comparative Example 1;
[0018] Figure 5 This is a schematic diagram of a capacitor without an insulating layer.
[0019] In the diagram: 1-outer shell, 2-capacitor core, 21-lead wire, 22-fixing strap, 23-electrolytic paper, 3-cover plate, 31-lead end, 4-insulating layer, 41-through hole. Detailed Implementation
[0020] The technical solution of this utility model is further described below, but the scope of protection is not limited to what is described.
[0021] Example 1:
[0022] like Figures 1 to 3 As shown, a capacitor for preventing degradation of conductive polymer includes a housing 1, a capacitor core 2, and a cover plate 3. The capacitor core 2 is disposed inside the housing 1 and has leads 21, a fixing strap 22, and an insulating layer 4. The cover plate 3 is connected to the housing 1 and has leads 31. The capacitor core 2 is connected to the leads 31 through the leads 21. The insulating layer 4 is disposed between the capacitor core 2 and the cover plate 3, and the leads 21 pass through the insulating layer 4.
[0023] The capacitor core 2 is made of a combination of positive electrode foil, negative electrode foil, electrolytic paper 23, and solid conductive polymer material. The lead wire 21 is a lead foil. The fixing tape 22 is a high-temperature adhesive tape used to fix the capacitor core 2. The lead end 31 is a solder pin.
[0024] The lead wire 21 and the lead end 31 are connected and fastened by rivets.
[0025] The insulating layer 4 is arranged in a circular sheet shape. One or more layers of insulating layer 4 can be provided as needed. The insulating gasket material used in the insulating layer 4 is polytetrafluoroethylene (PTFE), with a thickness of 0.2 mm.
[0026] 1.0mm, with a diameter of 22mm to 33mm.
[0027] An insulated layer 4 has a through hole 41 with a diameter of 6mm to 8mm, through which the lead wire 21 passes through the insulated layer 4.
[0028] Two through holes 41 are provided on the insulating layer 4 so that the positive and negative leads 21 can pass through respectively.
[0029] The two through holes 41 are set at an angle of 90° to 180° with the center point of the insulating layer 4, which facilitates the deployment of the lead wire 21.
[0030] The method for preparing this capacitor includes: first, riveting the lead wires 21 to the positive and negative electrode foils respectively; then, winding the positive and negative electrode foils and electrolytic paper 23 into a cylindrical capacitor core 2 in a certain number of layers and order, fixing it with a fixing strap 22, and impregnating it in a PEDOT:PSS dispersion solution under vacuum and pressure; finally, riveting the lead wires 21 to the lead ends 31 to bring out the positive and negative electrodes, and sealing the cover plate 3 and the aluminum shell 1 with rolled edges to form a sealed structure, thus forming a pin-covered capacitor.
[0031] Figure 1 Point A in the middle is the riveting point; Figure 2 At point B, the insulating layer 4 isolates the capacitor core 2 from the lead wire 21; Figure 4 , 5 Point C in the middle is a schematic diagram of the lead wire 21 pressing against the capacitor core 2; Figure 4 Point D in the middle indicates the case where there is no isolation layer.
[0032] Comparative Example 1:
[0033] like Figure 4 As shown, a capacitor that prevents the degradation of conductive polymer is basically the same as that in Example 1, except that the insulating layer 4 is not provided.
[0034] The capacitors with specifications of 100V and 1800μF prepared in Example 1 and Comparative Example 1 were tested at a temperature of 125℃ and a constant voltage of 100V for 24 hours. Two capacitors were set in each group, and the results are shown in the table below.
[0035]
[0036] As shown in the table above, the capacitors without insulation layers exhibited degradation of 4.50% and 4.77%, respectively, and increased losses of 36.4% and 43.9%, respectively. In Example 1, the capacitors showed degradation of 0.11% and 0.16%, respectively, and increased losses of 1.57% and 5.36%, respectively. This method, by adding insulation protection, prevents the degradation of the electrical performance parameters of the capacitor after electrical aging, effectively reducing abnormal capacitance degradation and loss reduction.
Claims
1. A capacitor that prevents degradation of conductive polymers, characterized in that: The device includes a housing (1), a capacitor core (2), and a cover plate (3). The capacitor core (2) is disposed inside the housing (1). The capacitor core (2) is provided with lead wires (21), a fixing strap (22), and an insulating layer (4). The cover plate (3) is connected to the housing (1). The cover plate (3) is provided with lead terminals (31). The capacitor core (2) is connected to the lead terminals (31) through the lead wires (21). The insulating layer (4) is disposed between the capacitor core (2) and the cover plate (3). The lead wires (21) are disposed through the insulating layer (4).
2. The capacitor for preventing degradation of conductive polymers as described in claim 1, characterized in that: The lead wire (21) and the lead end (31) are fastened together by rivets.
3. The capacitor for preventing degradation of conductive polymers as described in claim 1, characterized in that: The insulating layer (4) is arranged in a circular sheet shape.
4. A capacitor for preventing degradation of conductive polymers as described in claim 1, characterized in that: The insulating layer (4) is provided with a through hole (41), and the lead wire (21) passes through the insulating layer (4) through the through hole (41).
5. A capacitor for preventing degradation of conductive polymers as described in claim 4, characterized in that: Two through holes (41) are provided on the insulating layer (4).
6. A capacitor for preventing degradation of conductive polymers as described in claim 5, characterized in that: The two through holes (41) are set at an angle of 90° to 180° to the center point of the insulating layer (4).