DE102004045182A1 - Capacitor module for use in main power supply of automobile, has set of capacitors arranged in cup-shaped module housing, where gap is provided between two adjacent condensers and housing is sealed externally - Google Patents

Abstract

The module has a cup-shaped module housing (1) and a set of capacitors (5) arranged in the housing. A gap (A) is provided between two adjacent condensers, where the module housing is sealed externally. The module housing is filled with a medium e.g. polyurethane, which has a high thermal conductivity as air. The capacitors are formed with housings (6), which have a thermal transfer coefficient that is larger or equal to 0.4.

Description

The The invention relates to a capacitor module.

electrochemical Double layer capacitors usually have cell voltages of less than 3 V. For this reason, several of these capacitors Connected in series to higher voltage applications to reach necessary tensions. Such series connections of Capacitors are often called capacitor modules. For example a capacitor module for the use in the 42 V electrical system of automobiles from 18 series connected Constructed capacitors.

to Improved handling, to protect the capacitors before Dust, oil and water as well as protection against contact The series capacitors are comprised of a module housing. Heat when charging and discharging the individual capacitors due to their internal resistance. By this warming increases the aging rate of the capacitors, so the useful life of the capacitor module is reduced.

Out US 20030067735 A1 Capacitors are known whose lids have two terminals, which are connected in series by means of a printed circuit board. The capacitor module or capacitors are actively cooled by means of fans. The housing has openings through which air can enter.

It The present invention is based on the object, a capacitor module in which the capacitors operate stably and against external environmental conditions protected can be.

The The object is solved by the features of the independent claim. advantageous Embodiments of the invention will be apparent next to the following Description also from the dependent claims.

• – ein becherförmiges Modulgehäuse,
• – mehrere im Modulgehäuse angeordnete Kondensatoren, wobei zwischen zwei benachbarten Kondensatoren ein Abstand vorgesehen ist,
• – das Modulgehäuse nach außen abgedichtet ist.

A capacitor module is proposed, comprising:

• A cup-shaped module housing,
• A plurality of capacitors arranged in the module housing, wherein a gap is provided between two adjacent capacitors,
• - The module housing is sealed to the outside.

through of the outside sealed module housing can the capacitors from external influences, such as z. Dust, oil, Water and touch, protected become.

moreover advantageously remains out of the capacitors emerging Electrolyte, for example when the capacitors overcharge were, in the module housing and thus can not go outside escape. This is also the case when the capacitors with additional Predetermined breaking points are equipped, which are triggered when overcharging the capacitor to break off the current to the capacitor and / or the electrolyte preferably to escape in a controlled manner.

The capacitor module is preferably expanded in that a minimum distance between two adjacent capacitors lies in a range which corresponds to the formula A = αd 2 - βd + ε (1) where A is the minimum distance in mm, d is the cross-sectional maximum diameter of the larger capacitor in mm, α is a value between 0.0003 and 0.015, β is a value between 0.05 and 0.1 and ε is a value between 4 and 8 is. In the maintenance of such a minimum distance between two adjacent capacitors is advantageously achieved that a medium located between the capacitors, in the case that it is a gas, a liquid, amorphous or at least one movable within the capacitor module medium, can move through the entire capacitor module , does not get stuck between the capacitors and / or there is no heat buildup. A heat convection within the capacitor module is therefore achievable, which contributes in particular to the temperature stabilization of the capacitors.

in the Capacitor module is preferably arranged a fan to the convection of the medium between the capacitors to promote.

It it is preferred that the space between the adjacent capacitors partially or completely filled with a medium having a higher thermal conductivity has as air. The medium can have a solid form or record a solid form. A cooling of the capacitors or a heat dissipation from the capacitors to the outside can be particularly encouraged be when the medium is a potting compound, which, for example Polyurethane contains.

By the optimization of the heat balance through the above measures The capacitor module can advantageously also at ambient temperatures operated, where modules without optimized heat balance already exceed the upper operating temperature of the capacitors would.

The Invention will become apparent from the following embodiments and figures explained in more detail. Showing:

1 a capacitor module in which capacitors are contained, which have a certain distance A from each other,

2 a capacitor module in which fans are arranged in the module housing,

3 a capacitor module in which the spaces between the capacitors and between the capacitors and the module housing are at least partially filled with a medium,

4 a graph showing the optimal distances between capacitors with different diameters at different temperatures,

5 a graph showing the optimal distances between capacitors versus their different diameters.

modules with open module housings and active cooling have the advantage that the heat effectively out of the module to the outside guided can be. However, you can environmental influences unhindered from the outside penetrate into the module and the capacitors, for example by Corrosion, destroy. A possibility, to reduce the influence of external environmental factors lies in it, the openings the module housing, where a cooling air from the outside led into the capacitor module will, with dust / oil filters to provide. Such filters would reduce the effectiveness of the cooling, however significantly reduce. About that addition is a regular exchange the filter necessary.

Also when using double-layer capacitors, which has a can have very low internal resistance, internal losses not neglected become. For this reason, heat generation and dissipation play also a big one Role for Double-layer capacitor concepts.

1 shows a capacitor module with a module housing 1 in which a plurality of capacitors are arranged in rows and columns. The capacitors can be present in pairs. The separated by a minimum distance A from each other and with capacitor housings 6 trained capacitors 5 , each with diameters d, are preferably one end face to the bottom 2 the module housing by means of gluing, welding or screw connection flat. The module housing includes a lid 4 , a floor 2 and side walls or a coat 3 , It is preferred that the distance between two adjacent capacitors according to said formula (1) is chosen. The capacitors are preferably between 170mm and 50mm high.

Of the Minimum distance A between two adjacent capacitors, in which

I.

• a. the diameter d at least one of these Capacitors 45 to 55mm, preferably 50mm, is
• b. the other capacitor has a same or smaller diameter is preferably between 1.5 and 6.75 mm.

II.

• a. at least one of these capacitors one Diameter d is between 70 and 80mm, preferably 75mm,
• b. the other capacitor is the same or smaller diameter preferably is between 1.93 and 8.93mm.

III.

• a. at least one of these capacitors one Diameter d is between 85 and 95 mm, preferably 90 mm,
• b. the other capacitor is the same or smaller diameter is preferably between 1.93 and 9.83 mm

• – einem Laden und Entladen der Kondensatoren bei 75 A, welches eine Verlustleistung von 25W des Kondensatormoduls entspricht,
• – einem 150F/42V Modul, welches aus 18 Kondensatoren je 2,3 bis 2,7V Zellspannung besteht und damit einen gesamten Kapazitätswert von 2700F aufweist,
• – Umgebungsraumtemperaturen, beispielsweise bei 300 K, erreicht.

With these minimum distances, the temperatures of the individual capacitors could and can be reduced by up to approx. 7 K. The temperature reduction was at

• Charging and discharging of the capacitors at 75 A, which corresponds to a power loss of 25 W of the capacitor module,
• A 150F / 42V module, which consists of 18 capacitors each 2.3 to 2.7V cell voltage and thus has a total capacitance value of 2700F,
• - Ambient room temperatures, for example at 300 K, achieved.

It has been found that with the minimum distances one Temperature reduction also for smaller modules, e.g. Modules of 6 or 12 capacitors achieved can be. The reduction of temperatures by up to 7 K is especially compared to a capacitor module to understand in which the capacitors only a distance of less than 1.93 mm apart. A capacitor module designed in this way has such a highly optimized heat balance that despite the missing openings of the module housing the heat generated when charging or discharging the capacitors effectively inside the module housing dissipated can be. Therefore, such a capacitor module is because of the lower internal temperatures with a longer one Useful life and can still at higher outdoor temperatures can be operated as capacitor modules with closed housings without a sufficient distance between the capacitors. Despite the optimized heat dissipation can Environmental influences of Outside Do not further damage the capacitors contained in the capacitor module or after the response of one or more predetermined breaking points, for example by extreme overvoltage the capacitors, no electrolyte from the module housing after Outside reach.

The capacitors 5 can be connected in parallel with each other with the symmetries not shown in the figure for the voltage balance. It is preferred that the symmetries either thermally with the module housing 1 connected or attached outside the module housing. This ensures that the balancing currents flowing through the balancing resistors do not contribute to the heating of the capacitor module (when positioned outside the module housing) or only slightly (when positioned in the module housing with thermal connection to the module housing).

It It is preferred that capacitors with an optimum operating of between 300 and 310K, where they have one maximum duration at a certain frequency are dischargeable.

Another measure to optimize the thermal budget of the module housing is the use of dark-colored conditions, such as black or anodized capacitor housings 6 with thermal emission coefficients E of at least 0.4, preferably 0.5. By this measure, the thermal emission coefficient of the capacitors 5 improves, so that the heat generated by the capacitors more effective to the outside or at least to the module housing 1 can be transferred. The thermal emission coefficient E is the proportionality factor representing a relationship between the radiated heat per unit area Q / A of the heat generating medium or capacitor and its temperature T, where Q / A = E * σ * T ⁴ and σ is the Boltman constant.

To improve the heat transfer from the inside of the module to the outside is proposed, the lid 4 of the module housing 1 or at least a part of the cover, preferably the outer surface, to be made of a material which has a large heat conduction. The material is preferably a Metal or a metal alloy, which preferably contains aluminum. The lid can also be anodized and / or dark-colored and preferably has surface-enlarging structures, such as rib structures. With these properties, the lid should then preferably have an emission coefficient of greater than 0.4. Thus, the heat from the inside of the module can be dissipated particularly well.

It is convenient if the module housing 1 at least in part, such as the sidewalls 3 or the ground 2 , such mentioned material and structural properties as the lid.

2 shows a closed module housing 1 in which at least one fan 7 with a blowing direction 9 approximately parallel to the longitudinal axes of the capacitors 5 is arranged. The at least one fan 7 has a suction surface, which is sufficiently removed from the inner wall of the module housing in order to suck and transport as much gas or air as possible. By means of the fans, the heat convection in the module housing is significantly improved, so that the through the capacitors 5 resulting heat can be effectively transported to the module housing. In the case that a plurality of capacitors are arranged in the module housing, it is preferred that a corresponding number of fans are used to better compensate for the congestion of the air flows in the narrowest spaces between the capacitors and to achieve an overall larger air flow between the capacitors. It can be used fans in the size of 160 mm ² , as used for example in computer housings. The pressure generated by the fan can be in the range of 20 Pascals.

With adequate air circulation, especially under use the mentioned fans, it is possible the temperatures of the Capacitors in said capacitor modules in the preferred Range of 310K.

Should the capacitor module insulating plates between the individual capacitors It is preferred that these be either removed or at least be perforated so that as possible unhindered heat convection can take place.

3 shows a module housing 1 , which at least partially with a medium 8th . 8a is filled, which has a better thermal conductivity than air. The module housing is preference, in the bottom area B with the medium 8a , filled. The medium 8a For example, it may be a solid or solidifiable polyurethane potting compound. This will become part of the capacitor surfaces 6 in area B of the module housing floor 2 , in particular the bottom-side end faces of the capacitors, thermally connected directly to the module housing, so that the resulting heat can be dissipated or discharged via the module housing to the outside. The module housing can also be filled on the cover side in the same way with the medium to thermally connect the cover-side part of the capacitor surfaces directly to the module housing.

It is preferred that the module housing in area B of the floor 2 or lids 4 is filled at a height of B = 20 mm with a potting compound, which has a thermal conductivity of 0.7 W / m * K. Alternatively, the entire space between the capacitors and the inner walls of the module housing with a medium 8th respectively. 8a be filled of the type mentioned, wherein the medium may be a fluid in the form of a gas or a liquid. This can be achieved at the same time a heat convection and heat dissipation. In the event that a liquid is used, the fans can 7 be replaced with pumps.

A combination of embodiments according to the 2 and 3 is of course also possible, so that at the same time an air circulation between the capacitors of the module housing by means of the fans 7 and heat dissipation by means of the potting compounds 8th respectively. 8a can be achieved.

• 1. Es sind 18 Kondensatoren in einem 150F/42V Modul vorhanden (das Modul hat also einen Kapazitätswert von 2700F),
• 2. Die Kondensatoren weisen Emissionskoeffizienten von 0,4 bis 0,5 auf,
• 3. Die Temperaturen der Kondensatoren sind im Gleichgewichtszustand, d.h., die Kondensatoren werden solange mit 75 A (Verlustleistung von 25 W für das Modul) zykliert, bis diese eine konstante Temperatur erreichen,
• 4. Die Umgebungstemperatur liegt bei 300 K oder im unmittelbaren Bereich von 300 K.

4 shows the relationship between the distances between two capacitors and their respective temperatures under the following conditions:

• 1. There are 18 capacitors in a 150F / 42V module (so the module has a capacitance value of 2700F),
• 2. The capacitors have emission coefficients of 0.4 to 0.5,
• 3. The temperatures of the capacitors are in equilibrium state, ie the capacitors are cycled with 75 A (power dissipation of 25 W for the module) until they reach a constant temperature,
• 4. The ambient temperature is 300 K or in the immediate vicinity of 300 K.

• – die durch rhombusförmige Datenpunkte gekennzeichnete Kurve C1 die maximale Temperatur der Oberflächen von mindestens zwei Kondensatoren mit Durchmessern von 90 mm in Abhängigkeit des Abstands A zwischen den Kondensatoren,
• – die durch quadratische Datenpunkte gekennzeichnete Kurve C2 die maximale Temperatur der Oberflächen von mindestens zwei Kondensatoren mit Durchmessern von 75 mm in Abhängigkeit des Abstands A zwischen den Kondensatoren und
• – die durch dreieckige Datenpunkte gekennzeichnete Kurve C3 die maximale Temperatur der Oberflächen von mindestens zwei Kondensatoren mit Durchmessern von 50 mm in Abhängigkeit des Abstands A zwischen den Kondensatoren.

In 4 shows:

• The curve C1 marked by rhombic data points the maximum temperature of the surfaces of at least two capacitors with diameters of 90 mm as a function of the distance A between the capacitors,
• The curve C2 marked by square data points indicates the maximum temperature of the surfaces of at least two capacitors with diameters of 75 mm as a function of the distance A between the capacitors and
• The curve C3 indicated by triangular data points, the maximum temperature of the surfaces of at least two capacitors with diameters of 50 mm as a function of the distance A between the capacitors.

The heat transfer via the jacket of the capacitor housing is for this capacitor arrangement preferably 21W / m ² .

It can be seen how the diameter d of a capacitor its temperature and thus also affects the temperature of its surrounding medium. The temperatures of capacitors with larger diameters are included equal distances to each other higher as the temperatures of capacitors with the smaller diameters. The three curves Cl to C3 are not only relative to each other evenly shifted, but of the essence or the actual Shape different. Therefore it becomes clear that the optimal distance between the capacitors depends on their respective diameters.

The dashed, horizontal line in 4 shows an optimal temperature of a capacitor at 306 K, at which temperature the following optimal distances between the capacitors were found:

5 shows under consideration of the too 4 specified boundary conditions, the ratio between the diameter d of a capacitor and the optimal distance of the capacitor to another. The points marked on the curve correspond to the crossing points of the in 4 shown, dashed line of the optimum temperature with the three curves shown here C1 to C3.

5 shows how increasing a condenser diameter leads to higher temperatures and thus requires a greater distance between it and another condenser. The ratio of the optimum distance between two capacitors and their diameters behaves quadratically, in particular according to the above formula A = αd ² - βd + ε, where A indicates the minimum distance between two capacitors and d the maximum diameter of the larger capacitor in mm is. If the capacitors have the same diameter, the value of this diameter is taken. If the capacitors each have different diameters, the minimum distance A between the region of its maximum cross section of the capacitor and the same region of the further capacitor is measured. However, since preferably cylindrical capacitors are used, the diameter of the capacitor is at the same time its maximum diameter. The minimum distance between the capacitors in this case would be the minimum distance between the sheaths 6 correspond to the capacitors. α is preferably a value between 0.0003 and 0.015, β a value between 0.05 and 0.11 and ε a value between 4 and 8.

It has proved to be particularly favorable exposed if α a Value between 0.0007 and 0.00011, β a value between 0.06 and 0.01 and ε is a value between 4 and 8.

It is preferred that the preferably with the ground 2 of the module housing connected end faces of the capacitors 56 to 76%, in particular 66%, make up the total area of the bottom of the module housing.

1

module housing

2

ground of the module housing

3

Side wall of the module housing

4

cover of the module housing

5

capacitor

6

capacitor case

7

fan

8th

filling medium a module housing

8a

filling medium in ground or cover-side area of Mo

dulgehäuses

9

direction an airflow

B

ground- or cover-side area of a module housing

d

diameter a capacitor

A

minimum distance between two capacitors

Claims (19)

Capacitor module, comprising: - a cup-shaped module housing ( 1 ), - several capacitors arranged in the module housing ( 5 ), wherein - between two adjacent capacitors, a distance (A) is provided, - the module housing is sealed to the outside. Capacitor module according to Claim 1, in which a minimum distance between two adjacent capacitors ( 5 ) lies in an area which according to the formula A = αd 2 - βd + ε where A is the minimum distance in mm, d is the cross-sectional maximum diameter of the larger capacitor in mm, α is a value between 0.0003 and 0.015, β is a value between 0.05 and 0.1 and ε is a value between 4 and 8. Capacitor module according to one of Claims 1 or 2, in which the minimum distance of a first capacitor ( 2 ), which has a cross-sectional maximum diameter of 45 to 55 mm, to a further capacitor ( 2 ) of the same or smaller diameter between 4 and 5 mm. Capacitor module according to one of Claims 1 or 2, in which the minimum distance of a first capacitor ( 2 ), which has a cross-sectional maximum diameter of 70 to 80 mm, to a further capacitor ( 2 ) of the same or smaller diameter between 5 and 6 mm. Capacitor module according to one of Claims 1 or 2, in which the minimum distance of a first capacitor ( 2 ), which has a cross-sectional maximum diameter of 85 to 95 mm, to a further capacitor ( 2 ) of the same or smaller diameter between 6 and 7 mm. Capacitor module according to one of the preceding claims, in which the capacitors ( 2 ) at a temperature between 300 and 310K have their optimum operating conditions at which they can be discharged over a maximum duration at a certain frequency. Capacitor module according to one of the preceding claims, in which the module housing ( 1 ) at least partially with a medium ( 8th ) is filled, which has a higher thermal conductivity than air. A capacitor according to claim 7, wherein the medium ( 8th ) is a fluid. Capacitor module according to one of Claims 1 to 7, in which the medium ( 8th ) is a potting compound. 10.condensator module according to one of claims 1 to 9, wherein the medium ( 8th ) Polyurethane. Capacitor module according to one of the preceding claims, in which the capacitors ( 5 ) are cylindrical. Capacitor module according to one of the preceding claims, in which the capacitors ( 5 ) with capacitor housings ( 6 ) are formed, which have thermal emission coefficients of greater than or equal to 0.4. Capacitor module according to one of the preceding claims, in which the capacitors ( 5 ) with a front side with the bottom of the cup-shaped module housing ( 1 ) are connected flat. Capacitor module according to one of the preceding claims, in which the module housing ( 1 ) a lid ( 4 ) having. Capacitor module according to one of the preceding claims, in which the module housing ( 1 ) at least partially has a thermal transition coefficient of greater than or equal to 0.4. Capacitor module according to one of the preceding claims, in which the module housing ( 1 ) is at least partially anodized. Capacitor module according to one of the preceding claims, in which the module housing ( 1 ) at least partially has a rib structure. Capacitor module according to one of the preceding claims, in which the module housing ( 1 ) consists at least partially of metal. A capacitor module according to claim 18, wherein the metal Contains aluminum. Capacitor module according to one of the preceding claims, in which in the module housing ( 1 ) at least one fan ( 7 ) is arranged.