High-voltage filter capacitor
The high-voltage filter capacitor addresses cooling inefficiencies by using parallel aluminum sheets with thermal conductor segments, enhancing thermal management and suitability for automotive applications.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- PIERBURG GMBH
- Filing Date
- 2024-11-13
- Publication Date
- 2026-05-21
AI Technical Summary
Existing high-voltage filter capacitors face issues with cooling efficiency, particularly in automotive applications, leading to overheating due to insufficient thermal management, which is exacerbated by series connections or multiple overlap regions in polymeric capacitors.
A high-voltage filter capacitor design featuring parallel layers of thin aluminum sheets with electrical isolation and dielectric polymeric filler matrix, incorporating thermal conductor segments in specific overlap regions to enhance thermal capacity and heat dissipation.
The design improves cooling capability, making it robust against overheating from voltage peaks and suitable for high EMC requirements in automotive applications.
Smart Images
Figure EP2024082134_21052026_PF_FP_ABST
Abstract
Description
[0001] PI. P.22042. WO / EB 13.11.2024
[0002] - 1 -
[0003] High-voltage filter capacitor
[0004] Description
[0005] The invention refers to a high-voltage filter capacitor which is typically used as a filter element in high-voltage applications to realize and fulfill EMC-requirements.
[0006] A typical application of a high-voltage filter capacitor is in a filter capacitor arrangement of an electric automotive driving arrangement, which is also known as a Y-link capacitor arrangement. Typically, a high-voltage filter capacitor has a capacity of less than 1 pF and has a withstand voltage of 5 to 10 kV. Especially for electric automotive applications, a high and longterm reliability is necessary so that ceramic capacitors are not suitable.
[0007] US 10 102 974 B2 discloses a polymeric capacitor which is suitable for high frequency applications and which is provided with a self-restoring polymeric matrix. However, for providing a satisfying withstand voltage, several of these polymeric capacitors would have to be connected in a series connection. Alternatively, the polymeric capacitor could be provided with up to 20 or even more transversal overlap regions of the internal aluminum sheet sections. This would result in a deteriorated cooling of the capacitor, in particular in the capacitor's middle zone remote from the end-sided contact electrodes which provide the major cooling performance.
[0008] It is an object of the invention to provide a reliable high-voltage filter capacitor with improved cooling capability. PI. P.22042. WO / EB 13.11.2024
[0009] - 2 -
[0010] This object is solved, according to the invention, with a high-voltage filter capacitor with the features of claim 1.
[0011] The high-voltage filter capacitor according to the invention is provided with several parallel layers of aluminum sheet sequences, whereas every sheet sequence consists of an identical and relatively large number of transversely thin aluminum sheet sections which are electrically isolated from each other and which lie in a longitudinal layer plane. Preferably, the number of sheet sections is even and is six or higher. The directly neighbored sheet sequences are provided in an equal transversal layer distance from each other which preferably is in the range of above 100 nm and below 1000 nm, and which is more preferably in the range of about 500 nm.
[0012] The aluminum sheet sections are electrically isolated from each other by a dielectric polymeric filler matrix.
[0013] The sheet sections of one of the sequence layers respectively overlap, seen in transversal direction, with the sheet sections of the neighbor sheet sequence by more than 30% and less than 50% of their longitudinal section lengths. In other words, the sheet sections of the neighbored sheet sequences are displaced with respect to each other in longitudinal direction so that they symmetrically overlap with each other, seen in transversal direction. The high-voltage filter capacitor is provided with at least 10, preferably with about 20 transversal overlap regions. Since the number of transversal overlap regions defines the withstand voltage of the filter capacitor, the withstand voltage of the high-voltage filter capacitor is at least 5 kV which is suitable for typical automotive applications with system voltages of 400 V or 800 V. PI. P.22042. WO / EB 13.11.2024
[0014] - 3 -
[0015] In at least one transversal thermal overlap region all sheet sections are provided with thermal conductor segments, respectively, which thermal conductor segments are transversely thicker than the basic thickness of the sheet sections which are not provided with a thermal conductor segment. The thermal conductor segments of one transversal overlap region together define a stack of thermal conductor segments. The thermal conductor segments are an integral part of the corresponding sheet section, consist of the same aluminum and define a single piece together with the corresponding sheet section.
[0016] Generally, the thermal overlap regions need not be provided in equal longitudinal distances, but are preferably provided in equal longitudinal distances to each other if more than two thermal overlap regions are provided.
[0017] Since the aluminum mass is increased in the thermal overlap regions, the overall thermal capacity of the high-voltage filter capacitor is increased accordingly so that extreme temperature peaks are avoided. Additionally, the thermal conductor segments have a large lateral end surface so that a substantially higher amount of thermal energy can be conveyed and discharged through the lateral end surfaces of the thermal conductor segments. As a result, the high-voltage filter capacitor is much more robust against overheating resulting from extremely steep and large voltage peaks. The high-voltage filter capacitor therefore is perfectly suitable as a Y-link capacitor for automotive applications which have high EMC requirements. PI. P.22042. WO / EB 13.11.2024
[0018] - 4 -
[0019] Preferably, all the thermal conductor segments protrude in the same transversal direction from the respective sheet section plane. As a result, the complete structure of the sheet sections is homogenous.
[0020] Preferably, the thermal conductor segments have a transversal thickness of at least 200% of the transversal thickness of the sheet sections in the nonthermal overlap regions. More preferably, the thickness of the thermal conductor segments is at least 300% of the transversal thickness of the sheet sections in the non-thermal overlap regions. As a result, the thermal capacity as well as the heat exchange surface at the lateral end surfaces of the thermal conductor segments is increased accordingly.
[0021] Preferably, at least three non-thermal overlap regions are provided between the consecutive thermal overlap regions, seen in longitudinal direction. The number of non-thermal overlap regions between two neighbored thermal overlap regions can be adapted to the thermal requirements. However, the number of thermal overlap regions should generally be as low as possible to reduce the expenditure of aluminum and to facilitate the production.
[0022] Preferably, the dielectric polymeric filler matrix is filled with additional thermal conductive particles to provide an increased, satisfying and sufficient thermal conductivity for discharging the thermal energy from the aluminum sheet sections.
[0023] Preferably, the dielectric polymeric filler matrix is a polyacrylic fiber. A polymeric filler matrix made of a polyacrylic fiber has high self-restoring qualities. PI. P.22042. WO / EB 13.11.2024
[0024] - 5 -
[0025] One embodiment of the invention is described with reference to the enclosed drawings, wherein
[0026] figure 1 shows schematically an automotive driving arrangement with a filter capacitor arrangement with two high-voltage filter capacitors at the connection lines connecting a traction battery with an electronic motor driving unit,
[0027] figure 2 shows schematically the high-voltage filter capacitor of figure 1 in a lateral view,
[0028] figure 3 schematically shows the high-voltage filter capacitor of figure 2 in a lateral view from the other side, and
[0029] figure 4 shows a detail IV-IV of the high-voltage filter capacitor of figure 3.
[0030] Figure 1 schematically shows an automotive driving arrangement 100 comprising an electric high-voltage traction battery 90, a battery charging interface 96, an electric traction engine 92, an electronic motor driving unit 94, and a filter capacitor arrangement 10 provided at two connection lines 81, 82 connecting the high-voltage traction battery 90 with the electronic motor driving unit 94. The high-voltage traction battery 90 and the electronic motor driving unit 94 are electrically connected to each other by two high-voltage connection lines 81, 82. The system voltage of the automotive driving arrangement 100 is typically 400 V or 800 V. PI. P.22042. WO / EB 13.11.2024
[0031] - 6 -
[0032] The filter capacitor arrangement 10 is provided with two separate filter elements 101, 102, each filter element 101, 102 being defined by a high-voltage filter capacitor 20. Each high-voltage filter capacitor 20 is connected to one of the two connection lines 81, 82 and to the car body electric ground 70. The high-voltage filter capacitors 20 typically have a capacity of less than 1 pF and have a withstand voltage of more than 5 kV.
[0033] The automotive driving arrangement 100 also comprises a so-called X-link capacitor 103 with a capacity of typically more than 100 pF and being electrically arranged between the two connection lines 81, 82.
[0034] The high-voltage filter capacitor 20 is shown in more detail in figures 2 to 4 which show the high-voltage filter capacitor 20 without any capacitor housing.
[0035] Figures 2 and 3 show the general structure of the high-voltage filter capacitor 20: The high-voltage filter capacitor 20 comprises in total 10 parallel layers of aluminum sheet sequences 22, 24. Each sheet sequence 22, 24 consists of an identical section number of fifteen transversely relatively thin aluminum sheet sections 30, 30', 31, 31', 32, 32' lying in ten longitudinal and parallel layer planes xy. Every aluminum sheet section 30, 30', 31, 31' 32, 32' has a basic transversal thickness z3 of about 10 nm, has a longitudinal section length x3 of about 6 mm, and a width in the cross direction y of about 7mm. The directly neighbored sheet sequences 22, 24 are provided in equal transversal layer distances dz2 two from each other of about 500 nm. The longitudinal distance dx3 between two directly adjacent PI. P.22042. WO / EB 13.11.2024
[0036] - 7 -
[0037] aluminum sheet sections 30, 30', 31, 31', 32, 32' of the same sheet sequence 22, 24 is about 500 pm.
[0038] The sheet sections 30, 31, 32 of a first group of the sequence layers 22 overlap, seen in transversal direction z, with the sheet sections 30', 31', 32' of the neighbored sheet sequences 24 of a second group with about 45 % of their longitudinal section length X3, so that in total 30 transversal overlap regions 40, 40' are defined. Every sixth overlap region is a thermal overlap region 40 were the respective sheet section 31, 31' is provided with a transversely thicker thermal conductor segment 41, 41' so that in total four thermal overlap regions 40 are defined with respectively five non-thermal overlap regions 40', seen in longitudinal direction x, between them. The thermal conductor segment 41, 41' is an integral part of the respective aluminum sheet section 31, 31', respectively.
[0039] All thermal conductor segments 41, 41' protrude to the same transversal direction z from the respective sheet section 31, 31'. The thermal conductor segments 41, 41' have a total transversal thickness z4 of about 40 nm and have a longitudinal length x4 of a bit less than 50% of the longitudinal section length x3 of the sheet sections 30, 30', 31, 31', 32, 32'.
[0040] All aluminum sheet sections 30, 30', 31, 31', 32, 32' are embedded in a dielectric polymeric filler matrix 60 which is, in the present embodiment, a polyacrylic fiber material filled with additional thermal conductive particles.
[0041] The high-voltage filter capacitor 20 is provided with two metal connector electrodes 51, 52 at the longitudinal ends, whereas every connector electrode 51, 52 is electrically connected to the terminal sheet sections 32, PI. P.22042. WO / EB 13.11.2024
[0042] - 8 -
[0043] 32' of five of the ten sheet sequences 22, 24, respectively. The terminal sheet sections 32, 32' are provided with thicker aluminum connector segments 42 to realize a low-resistance soldering connection with the connector electrodes 51, 52.
Claims
PI. P.22042. WO / EB 13.11.2024- 9 -Claims1. A high-voltage filter capacitor (20) comprisingseveral parallel layers of aluminum sheet sequences (22, 24), each sheet sequence (22, 24) consisting of an identical large section number of transversely thin aluminum sheet sections (30, 30', 31, 31', 32, 32') lying in a longitudinal layer plane (xy),whereas all aluminum sheet sections (30, 30', 31, 31', 32, 32') are electrically isolated from each other by a dielectric polymeric filler matrix (60),whereas the directly neighbored sheet sequences (22, 24) are provided in equal transversal layer distances (z2) from each other, whereas the sheet sections (30, 31, 32) of one of the sequence layers (22) overlap, seen in transversal direction (z), with the sheet sections (30', 31', 32') of the neighbored sheet sequence (24) by more than 30 % and less than 50% of their longitudinal section lengths (x3) in a transversal overlap region (40, 40'), andwhereas in a at least one thermal overlap region (40) all sheet sections (31, 31') are provided with a transversely thicker thermal conductor segment (41, 41'), respectively.
2. The high-voltage filter capacitor (20) of claim 1, whereas all thermal conductor segments (41, 41') protrude in the same transversal direction (z) from the respective sheet section (31, 31').
3. The high-voltage filter capacitor (20) of one of the preceding claims, wherein the thermal conductor segments (41, 41') have a transversalPI. P.22042. WO / EB 13.11.2024- 10 -thickness (z4) of at least 200% of the transversal thickness (z3) of the sheet sections (30, 30', 31, 31', 32, 32') in the non-thermal overlap regions (40').
4. The high-voltage filter capacitor (20) of one of the preceding claims, wherein at least two thermal overlap regions (40) are provided.
5. The high-voltage filter capacitor (20) of the preceding claim, wherein at least three non-thermal overlap regions (40') are provided between the consecutive thermal overlap regions (40), seen in longitudinal direction (x).
6. The high-voltage filter capacitor (20) of one of the preceding claims, wherein the dielectric polymeric filler matrix (60) is filled with additional thermal conductive particles.
7. The high-voltage filter capacitor (20) of one of the preceding claims 5 or 6, wherein the dielectric polymeric filler matrix (60) is polyacrylic fiber.
8. An automotive driving arrangement (100) with an electric traction battery (90), an electric traction engine (92), an electronic motor driving unit (94) and a filter capacitor arrangement (10) at the connection lines (81, 82) connecting the traction battery (90) with the electronic motor driving unit (94),PI. P.22042. WO / EB 13.11.2024- 11 -whereas the filter capacitor arrangement (10) is provided with two filter elements (101, 102) being defined by the high-voltage filter capacitors (20) with the features according to one of the preceding claims.