DE102004045182B4 - capacitor module - Google Patents

Abstract

Capacitor module with a module housing (1) and a plurality of capacitors (5) arranged in the module housing, wherein
The module housing is sealed to the outside,
- The module housing is good heat conducting, and
At least one end side of the capacitors is thermally connected to the opposite side of the module housing by means of a good heat-conducting solid (8a) with the module housing,
- Between two adjacent capacitors dependent on the diameter of the capacitors minimum distance (A) is provided by the compliance of the convection of a fluid contained in the module housing is reached, wherein the convection contributes to the heat dissipation of the capacitors.

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.

Out EP 1178558 A2 is known a capacitor module, the capacitors are flowed around by air.

Out JP 11-054356 a capacitor module is known, the capacitors are surrounded by a liquid.

Out DE 10124435 A1 a capacitor is known with a housing, wherein the housing of the capacitor is surrounded by a coolant jacket.

Out DE 3835484 A1 For example, a molded capacitor having capacitor elements that are housed in insulating housings filled with an insulating fluid is known.

Out DE 10 2004 035 810 A1 For example, a capacitor module is known in which a heat contact surface connected to a capacitor is connected to a housing surface by means of a mass. This should improve the dissipation of heat loss to the environment.

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.

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.

By means of the module housing sealed to the outside, the capacitors can be protected from external influences, such. As dust, oil, water and touch, are protected. In addition, advantageously, an emerging from the capacitors electrolyte, for example, when the capacitors were overloaded, in Module housing and thus can not escape to the outside. This is also the case when the capacitors are equipped with additional predetermined breaking points, which are triggered when overcharging the capacitor to break off the current to the capacitor and / or to allow the electrolyte escape as controlled as possible.

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 is filled with a fluid, partially or completely, which has a higher thermal conductivity has as air. A cool down the capacitors or a heat dissipation from the capacitors to the outside can be promoted in particular, if a medium that is a potting compound, for example Contains polyurethane, the capacitors have good thermal conductivity with the module housing combines.

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.

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 170 mm and 50 mm high.

• I.
• a. der Durchmesser d mindestens einer dieser Kondensatoren 45 bis 55 mm, vorzugsweise 50 mm, beträgt,
• b. der andere Kondensator einen gleichen oder kleineren Durchmesser hat, liegt vorzugsweise zwischen 1,5 und 6,75 mm.
• II.
• a. mindestens einer dieser Kondensatoren einen Durchmesser d zwischen 70 und 80 mm, vorzugsweise 75 mm, beträgt,
• b. der andere Kondensator einen gleichen oder kleineren Durchmesser hat, liegt vorzugsweise zwischen 1,93 und 8,93 mm.
• III.
• a. mindestens einer dieser Kondensatoren einen Durchmesser d zwischen 85 und 95 mm, vorzugsweise 90 mm, beträgt,
• b. der andere Kondensator einen gleichen oder kleineren Durchmesser hat,

liegt vorzugsweise zwischen 1,93 und 9,83 mmThe minimum distance A between two adjacent capacitors, in which

• I.
• a. the diameter d of at least one of these capacitors is 45 to 55 mm, preferably 50 mm,
• b. the other capacitor has the same or smaller diameter is preferably between 1.5 and 6.75 mm.
• II.
• a. at least one of these capacitors has a diameter d between 70 and 80 mm, preferably 75 mm,
• b. the other capacitor has a same or smaller diameter is preferably between 1.93 and 8.93 mm.
• III.
• a. at least one of these capacitors has a diameter d between 85 and 95 mm, preferably 90 mm,
• b. the other capacitor has 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 25 W des Kondensatormoduls entspricht,
• – einem 150 F/42 V Modul, welches aus 18 Kondensatoren je 2,3 bis 2,7 V Zellspannung besteht und damit einen gesamten Kapazitätswert von 2700 F 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 150 F / 42 V module, which consists of 18 capacitors each 2.3 to 2.7 V cell voltage and thus has a total capacitance value of 2700 F,
• - 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, such. B. 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 condensers Ren. 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 be used between 300 and 310 K, where they have a 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, 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 carried over. The thermal emission coefficient E is the proportionality factor, which is 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 Bolzmann 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 lid, preferably the outer surface, to be made of a material having a good 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 glass 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 to suck as much gas or air and be able to promote be. 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. Preferably, multiple fans are used to better balance the congestion of the airflows in the narrowest spaces between the condensers and to achieve an overall greater airflow between the condensers. It can be fans, such as those used in computer housings, are used. 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.

According to one embodiment of the capacitor module, it has insulating plates between the individual Capacitors on. However, it is preferred that these 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 preferably in the bottom area B with the heat-conductive solid 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 dulgehäuse Mo, so that the resulting heat can be dissipated via the module housing to the outside or derived. 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. Furthermore, the entire space between the capacitors and the inner walls of the module housing with a medium 8th 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 150 F/42 V Modul vorhanden (das Modul hat also einen Kapazitätswert von 2700 F),
• 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 150 F / 42 V module (so the module has a capacitance value of 2700 F),
• 2. The capacitors have emission coefficients of 0.4 to 0.5,
• 3. The temperatures of the capacitors are in equilibrium, ie the capacitors are cycled with 75 A (power loss 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 preferably 21 W / m ² for this capacitor arrangement.

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 higher to each other as the temperatures of capacitors with the smaller diameters. The three curves C1 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: diameter Optimal distance 50 mm 4.6 mm 75 mm 5.5 mm 90 mm 6,6 mm

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 Value is 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

fluid in the module housing

8a

solid fuel in the bottom or cover-side area of the module housing

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 (21)

Capacitor module with a module housing ( 1 ) and a plurality of capacitors arranged in the module housing ( 5 ), wherein - the module housing is sealed to the outside, - the module housing is good heat-conducting, and - at least one end side of the capacitors with the opposite side of the module housing by means of a good heat-conducting solid ( 8a ) is thermally connected to the module housing, - between two adjacent capacitors dependent on the diameter of the capacitors minimum distance (A) is provided by the compliance of the convection of a fluid contained in the module housing is reached, the convection contributes to the cooling of the capacitors. Capacitor module according to Claim 1, in which the good heat-conducting solid ( 8a ) is a potting compound. Capacitor module according to claim 2, wherein the potting compound Polyurethane is. Capacitor module according to one of the preceding claims, in which the capacitors ( 5 ) are connected to balances, wherein the balances thermally with the module housing ( 1 ) are connected. Capacitor module according to Claim 4, in which the balances outside the module housing ( 1 ) are attached. Capacitor module according to Claim 4, in which the balances within the module housing ( 1 ) and thermally connected to the housing. Capacitor module according to one of the preceding claims, in the thermally conductive Fluid is a gas. Capacitor module according to Claim 7, in which a fan (in the module housing) 7 ) is arranged for the circulation of the gas. Capacitor module according to one of the preceding claims 1-6, at the thermally conductive Fluid a fluid is. Capacitor module according to Claim 9, in which in the module housing ( 1 ) a pump for the circulation of the liquid ( 8th ) is arranged. Capacitor module according to one of the preceding claims, in which the minimum distance (A) between two adjacent capacitors lies in a range which corresponds 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, wherein the diameters of the individual capacitors are between 45 mm and 95 mm. Capacitor module according to one of the preceding claims, in which the capacitors ( 5 ) at a temperature between 300 K and 310 K have their optimum operating 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 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 at least 0.4. Capacitor module according to one of the preceding claims, in which the capacitors ( 5 ) with one end face with the bottom of the 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 emission 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 the module housing at least partially has a rib structure. Capacitor module according to one of the preceding claims, in the module housing consists of one of the following materials: metal, metal alloy, Aluminum. Capacitor module according to one of the preceding claims, in which the capacitors ( 5 ) Are double-layer capacitors.