DE102009020185A1 - Energy storage for hybrid vehicle, has safety device that is dimensioned to release closure of opening of battery case during exceeding pressure threshold value and/or temperature threshold value in battery case - Google Patents

Abstract

The storage (1) has battery cells connected in series and arranged in a hermetically closed battery case. A safety device (6) reduces the pressure in the battery case during malfunctioning of battery cells. The safety device is dimensioned to release a closure of an opening of the battery case during exceeding pressure threshold value and/or temperature threshold value in the battery case, where the safety device comprises housing wall area as closure of the opening. The closure of the safety device exhibits a plastic foil.

Description

The The invention relates to an energy store with housing for Vehicles. For this purpose, the energy storage battery cells, the essentially in series and hermetically sealed Battery housing are arranged. In addition, points the energy storage a safety device to reduce excess pressure in the battery case malfunction of the battery cells on.

Such an energy storage with a battery case and a battery module is from the document EP 1 519 430 A1 known. In this case, the known battery housing of the battery module has a nearly flat shape to accommodate the laminate-type battery cells in the housing. In addition, the battery case has a gas outlet device which is disposed on a wall of the battery case to discharge gas to the outside of the battery case. This gas is discharged in a malfunction of the laminate-type battery cells, wherein the battery case is deformed at the gas outlet to leave the gas using the gas outlet device to the outside. This improves the reliability of the battery in case of malfunction of the battery cells. Gas formation is not dependent on the cell shape, so that the problem can also occur in round cells and prismatic cells in a housing.

According to 5 In the prior art, in the battery case, an opening is closed by a plug, so that the battery case is hermetically sealed and malfunctioning of the battery cells in accordance with 10B the publication EP 1 519 430 the housing deformed at this vulnerability. In addition, notches are provided in the prior art as predetermined breaking points for a breakage of the housing in case of malfunction of the battery cells.

These Solution of a safety device to reduce overpressure in the battery case malfunction of the battery cells has the disadvantage that the battery case in the vicinity an opening is deformed and thus irreparable damage the housing the result of malfunction of the battery cells inside the hermetically sealed battery case is.

In Other solutions to this problem are usually the Housing hermetically sealed and in case of malfunction an opening is released. Such an opening is sealed with a sealing material which provides a secure seal guaranteed in normal operation. This seal is designed so that they prevail in the event of a malfunction Temperatures, pressures and released substances destroyed is and thus releases a vent. This will be an opening provided with a Goretex membrane. Because of their impermeability Fluids pass through the Goretex membrane prevents water from entering the energy storage system.

however is a Goretex membrane to water vapor and others gaseous substances permeable to the environment, so that, for example, the ingress of moist air into the system is not prevented. This is associated with the risk that when falling below the dew point in a humid air filled Energy storage system a condensation of water droplets within of the memory. Thus, this solution protects a battery with corresponding battery cells in normal operation not reliable. Such a moisture accumulation can even lead to increased heat accumulation.

task The invention is an energy storage with housing for vehicles, the disadvantages in the state of Technology overcomes and ensures that in normal operation the battery case is also hermetically sealed against gases remains closed and in case of malfunction of the battery cells is opened without doing the battery case is deformed.

These The object is with the subject of the independent claim 1 solved. Advantageous developments of the invention result from the dependent claims.

According to the invention an energy storage with housing for vehicles created. For this purpose, the energy storage battery cells, the essentially in series and hermetically sealed Battery housing are arranged. In addition, points the energy storage a safety device to reduce excess pressure in the battery case malfunction of the battery cells on. The safety device is dimensioned such that it when a pressure threshold and / or temperature threshold is exceeded in the battery case a closure of an opening of the battery case releases.

This Energy storage with housing for vehicles has the advantage that malfunctions of the battery cells in the Development of overpressure in the battery case the Battery case is not deformed and in normal operation It is ensured that even humidity is not in the interior the battery can penetrate.

As a sealing material is a switchable plastic film offers, with the degassing is taped. The switchable property of the film is achieved by dimensioning it will be able to withstand normal pressure and temperature fluctuations. In the case of malfunctions, however, it breaks up due to the resulting overpressure or melts due to the excess temperature or is dissolved by the liberated electrolyte. It is therefore used in a first embodiment of the invention, a switchable plastic. On the other hand, it is possible to use a metallized plastic film or a plastic-coated metal foil.

When Alternative to such films, the degassing also with a sufficiently thin plastic or metal plate to be introverted. Instead of the adhesive bond, the seal also with other joining techniques such as welding, soldering or other cohesive connection options be attached. Is the invention and Normally impermeable sealing of the vent realized by the film or by platelets is a complete protective sealing of the energy storage ensured against moisture and dirt.

in the Contrary to the known gas-permeable membranes also a condensation of the air humidity during the cooling in the Memory avoided, as in the film sealing no humid air can invade the memory. In case of malfunctions will destroys the seal, causing the vent is released and the energy store safely overpressure can degrade and thus an explosion, but at least a deformation of the battery case is avoided. This is the seal the energy storage system at over-temperature or at emerging substances from the energy storage at a defined Position of the housing repealed, bringing a gain in reliability and safety in the use of the energy storage system in particular connected in vehicles.

The The invention will now be more apparent from the accompanying drawings explained.

1 shows a schematic diagram of the arrangement of an energy storage in a vehicle;

2 shows with the 2A . 2 B and 2C schematic views of a battery segment of an energy storage with segment housing according to an embodiment of the invention;

3 to 15 show different embodiments of a safety device for an energy storage with housing according to the invention;

3 shows a schematic cross section through a formed in the housing safety device according to an embodiment of the invention;

4 shows a schematic cross section through a safety device according to another embodiment of the invention;

5 shows a schematic cross section through a safety device according to another embodiment of the invention;

6 shows a schematic cross section through a safety device according to another embodiment of the invention;

7 shows a schematic cross section through a safety device according to another embodiment of the invention;

8th shows a schematic cross section through a safety device according to another embodiment of the invention;

9 shows a schematic cross section through a safety device according to another embodiment of the invention;

10 shows a schematic cross section through a safety device according to another embodiment of the invention;

11 shows a schematic cross section through a safety device according to another embodiment of the invention;

12 shows a schematic cross section through a safety device according to another embodiment of the invention;

13 shows a schematic cross section through a safety device according to another embodiment of the invention;

14 shows a schematic cross section through a safety device according to another embodiment of the invention;

15 shows a schematic cross section through a safety device according to another embodiment of the invention.

1 shows a schematic diagram of the arrangement of an energy storage 1 with housing 2 in a vehicle 3 , Such a vehicle 3 can be a motor vehicle with hybrid drive, hybrid vehicles with a combustion engine and an electric machine and one or more electrochemical energy storage 1 exhibit. The electric machine of such a hybrid vehicle is usually as a starter / generator and / or electrical drive executed. As a starter / alternator, it replaces the normally existing starter and alternator in a conventional vehicle 3 , In addition, the electric drive of the hybrid vehicle, an additional torque and thus an additional acceleration in the propulsion of the vehicle 3 contribute through the electric machine. As a generator, the electric machine allows recovery or recuperation of braking energy, for example, to the electrical system supply.

The vehicle 3 but can also represent an electric vehicle with fuel cells or a pure electric vehicle, the fuel cell is used for energy conversion. The vehicle 3 may for this purpose have a tank for liquid or gaseous energy carriers, an electrochemical energy storage and an electric machine for the drive. Thus, in a pure electric vehicle, the drive power is provided only by an electric machine. However, both types of vehicle require a sufficient amount of electrical energy, which must be provided and transferred, including appropriately designed energy storage 1 be available or developed, such as lead acid batteries, double-layer capacitors, nickel-metal-hydride or lithium-ion cell batteries.

The housing 2 such an energy storage 1 Under normal operating conditions, this prevents the exchange of substances between the environment and the interior of the energy storage 1 , This will contaminate the energy storage 1 and thus prevents a risk of short circuit. Will the housing 2 For this media-dense running against gases and liquids, so the occurrence of humidity in the energy storage system can be avoided. This prevents the formation of condensation moisture and thus the risk of corrosion and short circuits within the storage tank. However, malfunctions are possible, such. As an overload or over temperature, which may lead to the opening of individual or multiple battery cells. The opening of the battery cells leads to an increase in pressure within the battery system. In order to avoid that the battery system bursts or even explodes, it is inventively provided, the resulting pressure from the energy storage 1 about a security device 6 having a degassing opening and a closure of the degassing opening to lead safely.

2 shows schematic views of a battery segment 25 an energy store 1 according to an embodiment of the invention. In addition shows 2A a cross section through the battery segment 25 and 2 B a plan view of the battery segment 25 such as 2C a side view of the battery segment 25 , This can be done by the battery segment 25 a housing 5 in a housing wall area 9 a inven tion proper safety device 6 having. Instead of the battery segment shown here 25 with four flat lithium-ion cells 23 As battery cells, the battery case 5 also have round or prismatic cells. In addition, an arbitrarily high number of such battery cells can be provided in series in order to provide correspondingly high battery voltages available. The battery case shown here 5 points in a housing wall area 9 who in 2A is shown, a safety device according to the invention 6 on, with the following detail drawings 3 to 15 is explained in more detail, while the opening shown is suitable for all energy storage regardless of the design of the cells.

3 shows a schematic cross section through a in the housing 5 molded safety device 6 according to an embodiment of the invention. This is done during injection molding of the housing 5 in a housing wall area 9 an opening 8th provided with a molded cover 10 which has a significantly smaller thickness than the walls of the housing 5 has hermetically closed. At the side edges of the cover 10 are undercuts 24 provided in the event of malfunction and exceeding a pressure threshold within the housing 5 the cover along the track of the undercut 24 out of the case 5 pops out, taking a through the undercuts 24 clearly demarcated area the opening 8th whose contour then allows the opening 8th for example, by a plug or a separate plate to close again and thus the housing 2 to be used again in an advantageous manner.

4 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention. From the above prior art, only a plug of such a safety opening is known, which ensures that a developing pressure increase deforms the housing and the wall in the vicinity of the housing plug.

According to the invention 4 the opening 8th a slide 17 as a cover whose material is gas and liquid-tight, wherein the film 17 on edge areas 12 the opening 8th is fixed gas- and waterproof with the help of an adhesive seam, so that even humidity can not penetrate into the interior of the energy storage. For this purpose, self-adhesive films or films can be used by a liquid adhesive, a hot melt adhesive or a wax on the edges 12 the opening 8th be fixed. In addition to plastic films are also metallized plastic films that are particularly moisture-proof or plastic-coated metal foils suitable, the plastic coating allows a material connection with a plastic housing.

The adhesive seam may, for example, comprise bitumen or a ring of film coated on both sides with bitumen 17 be so that the opening of the vent can be done by melting the adhesive with temperature increase within the memory in case of malfunction. Moreover, it is possible with the help of the adhesive seam 13 to create such a material connection that tears the plastic film in case of malfunction.

5 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention. In this embodiment, a plastic film 17 made of thermoplastic material such as polyethylene, polypropylene or polycarbonate on the edge area 12 welded the opening. As a welding process ultrasonic welding and laser welding can be used here. In case of malfunction of individual battery cells, the security film 17 burst, without the case 5 is deformed.

6 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention. In this case, instead of a plastic film, a metal foil 21 , preferably a copper or aluminum or a tin foil on the edge region 12 the opening 8th glued. In this case, as discussed above, the metal foils have a plastic coating, wherein the plastic coating serves a cohesive connection with the plastic housing. In case of malfunction results in a similar effect as in the safety device 6 according to 4 in that, for example, the adhesive seam melts and the metal foil melts 21 from the opening 8th takes off.

7 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention, wherein a metal foil 21 on the edge area 12 the opening is welded. Again, an ultrasonic welding process or a laser welding process can be used to provide a hermetic seal between a battery case 5 for example, plastic and the cover of the opening 8th from a metal foil 21 to ensure.

8th shows a schematic cross section through a safety device 6 according to a further embodiment of the invention. In this embodiment of the invention is used as a cover 10 the opening 8th a plastic plate 16 used and on the edge area 12 the opening 8th with the help of an adhesive seam 13 fixed.

9 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention. In this case, the plastic tile 16 not glued, but welded according to the above-mentioned method, so that a cohesive connection between the plastic material of the housing 5 and the plastic material of the plastic plate 16 arises. The thickness of the plastic plate 16 is chosen so that it destroys the plastic plate as far as possible in case of malfunction within the energy storage and when exceeding a permissible internal pressure, so that the excess pressure from the battery case 5 can escape.

10 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention. In this case, that is in 8th shown plastic plates by a metal plate 15 replaced and on the edge area 12 the opening 8th glued.

11 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention. In this embodiment of the invention, the metal plate is 215 as a cover 10 on the edge area 12 the opening 8th welded. Such welded plastic-metal compounds are possible, but they require a reduced thickness of the metal plate 15 opposite the thickness of the plastic plate 16 in the 8th and 9 ,

12 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention, wherein a wax platelet 22 on the edge area 12 the opening 8th with the help of an adhesive seam 13 is glued on. Such a wax plate 22 is carried out in a significantly greater thickness than the preceding films and platelets and is particularly sensitive to temperature, so that this solution is used in energy storage with battery cells that develop high temperatures in case of malfunction, through which the wax platelet is melted.

13 shows a schematic cross section through a safety device 6 according to a further embodiment of the invention. In this embodiment of the invention, the opening 8th with a wax plug 18 closed, in the opening 8th and on the edge area 12 the opening is infused. Instead of a wax stopper 18 can also be a plastic stopper 19 as he is in 14 is shown, or a plug of a low-melting metal alloy, as it 15 shows in the opening 8th and on the edge area 12 the opening to be poured.

With the in the 3 to 15 listed embodiments of the safety device 6 It is possible that in case of malfunction and when a pressure or temperature threshold is exceeded, the opening 8th is released, without doing the case structure of the battery case 5 is deformed and thus can be used again. Another protective measure, not shown, is to provide, for example, a protective grid, a labyrinth or the like as a mechanical protection in addition to the above-mentioned safety devices.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 1519430 A1 [0002]
• EP 1519430 [0003]

Claims (12)

Energy storage with housing ( 2 ) for vehicles ( 3 ) comprising: - battery cells ( 4 ), which are essentially connected in series and in a hermetically sealed battery case ( 5 ) are arranged; - a security device ( 6 ) for reducing excess pressure in the battery housing ( 5 ) in case of malfunction of the battery cells ( 4 ); characterized in that the security device ( 6 ) is dimensioned such that, when a pressure threshold value and / or temperature threshold value in the battery housing is exceeded ( 5 ) a closure ( 7 ) an opening ( 8th ) of the battery case ( 5 ) releases. Energy store according to claim 1, characterized in that the safety device ( 6 ) a housing wall area as a closure ( 7 ) of the opening ( 8th ), whose material thickness is so lower than the material thickness of the battery case ( 5 ) that when a pressure threshold and / or temperature threshold value is exceeded, the closure ( 7 ) burst. Energy store according to claim 1 or claim 2, characterized in that the closure ( 7 ) of the security device ( 6 ) a cover ( 10 ) of the opening ( 8th ) which bursts when a pressure threshold is exceeded. Energy store according to one of the preceding claims, characterized in that the closure ( 7 ) of the security device ( 6 ) a cover slip ( 11 ), which is provided with a peripheral region ( 12 ) of the opening ( 8th ) cohesively by means of an adhesive seam ( 13 ), which is exceeded when a pressure threshold value and / or temperature threshold value is exceeded by lifting the cover plate ( 11 ) of the adhesive seam ( 13 ) the opening ( 8th ) releases. Energy store according to claim 1 or claim 2, characterized in that the closure ( 7 ) of the security device ( 6 ) a cover slip ( 11 ), which is provided with a peripheral region ( 12 ) of the opening ( 8th ) cohesively by means of a weld ( 14 ) is connected such that when a pressure threshold value and / or temperature threshold value is exceeded, the cover plate ( 11 ) burst. Energy store according to one of the preceding claims, characterized in that the closure ( 7 ) of the security device ( 6 ) a metal plate ( 15 ), which is provided with a peripheral region ( 12 ) of the opening ( 8th ) cohesively by means of an adhesive seam ( 13 ) is connected such that when a pressure threshold value and / or temperature threshold value is exceeded, the metal plate ( 15 ) from the opening ( 8th ) takes off. Energy store according to one of the preceding claims, characterized in that the closure ( 7 ) of the security device ( 6 ) a metal plate ( 15 ), which is provided with a peripheral region ( 12 ) of the opening ( 8th ) cohesively by means of a weld ( 14 ) is connected such that when a pressure threshold value and / or temperature threshold value is exceeded, the metal plate ( 15 ) burst. Energy store according to one of the preceding claims, characterized in that the closure ( 7 ) of the security device ( 6 ) a plastic plate ( 16 ), which is provided with a peripheral region ( 12 ) of the opening cohesively by means of an adhesive seam ( 13 ) is connected such that when a pressure threshold value and / or temperature threshold value is exceeded, the plastic chip ( 16 ) from the opening ( 8th ) takes off. Energy store according to one of the preceding claims, characterized in that the closure ( 7 ) of the security device ( 6 ) a plastic film ( 17 ) having an edge region ( 12 ) of the opening ( 8th ) cohesively by means of an adhesive seam ( 13 ) is connected such that when a pressure threshold value and / or temperature threshold value is exceeded, the plastic film ( 17 ) burst. Energy store according to one of the preceding claims, characterized in that the closure ( 7 ) of the security device ( 6 ) a wax plug ( 18 ), which in the opening ( 8th ) is poured. Energy store according to one of the preceding claims, characterized in that the closure ( 7 ) of the security device ( 6 ) a plastic stopper ( 19 ) or metal plugs ( 20 ) of a material having a lower melting point than the material of the battery casing ( 5 ), the stopper ( 19 . 20 ) in the opening ( 8th ) is poured. Energy store according to one of the preceding claims, characterized in that the opening through from the inside attached platelets or foils is secured.