DE102019127637A1 - Electrical energy storage with a best membrane and with a cooling device, as well as process - Google Patents

Abstract

The invention relates to an electrical energy store (10) for a motor vehicle, with at least two battery cells (12, 14, 16, 18), with a cooling plate (26) on which the battery cells (12, 14, 16, 18) are arranged, with between of a respective battery cell (12, 14, 16, 18) and the cooling plate (26), a respective bursting membrane (28) is arranged at least in some areas, which in the event of a thermal runaway (58) of one of the battery cells (12, 14, 16, 18) for Bursting and designed to discharge a hot gas (30) that has arisen to the cooling plate (26), a cooling device (24) being formed on a side (32) of the battery cells (12, 14, 16, 18) opposite the cooling plate (26) , which is coupled to the at least two battery cells (12, 14, 16, 18), wherein the cooling device (24) is designed to transfer a cooling medium (34) into an interior (26) of the Inject battery cell (12, 14, 16, 18). The invention also relates to a method.

Description

The invention relates to an electrical energy store for an at least partially electrically operated motor vehicle according to the preamble of patent claim 1. Furthermore, the invention relates to a method for cooling an electrical energy store.

It is known from the prior art that electrical energy storage devices for at least partially electrically operated motor vehicles, in particular for fully electrically operated motor vehicles, can be seriously damaged if a battery cell in the electrical energy storage device thermally runs through. This can in particular lead to the fact that further still functional electrical battery cells of the electrical energy store can also be damaged, for example, if one of the battery cells should thermally break down. Furthermore, this can lead to total damage to the electrical energy store.

The DE 10 2017 212 223 A1 relates to a battery of an electrically powered motor vehicle, with a number of energy storage cells, each having an electrical connection and a cell housing with a housing opening provided on a first housing side, which is closed with a bursting membrane, and with a cooling plate arranged between the cell housing and a cell degassing space with a feedthrough which is aligned with the housing opening or at least partially overlaps, the cooling plate having an inlet opening into the feedthrough for supplying a coolant into the cell housing, which is blocked by means of a closure that opens when triggered.

The object of the present invention is to create an electrical energy store and a method by means of which the electrical energy store is protected against thermal runaway in an improved manner.

This object is achieved by an electrical energy store and by a method according to the independent claims. Advantageous embodiments are specified in the subclaims.

One aspect of the invention relates to an electrical energy store for an at least partially electrically operated motor vehicle, with at least two battery cells, with a cooling plate on which the at least two battery cells are arranged, with a respective bursting membrane being arranged at least in some areas between a respective battery cell and the cooling plate, which, in the event of a thermal runaway of one of the battery cells, are designed to burst at a predetermined temperature and to discharge a hot gas produced during the thermal runaway from this battery cell to the cooling plate.

Provision is made for a cooling device to be formed on a side of the battery cells opposite the cooling plate, which is coupled to the at least two battery cells, the cooling device being designed to inject a cooling medium into an interior of the thermally broken battery cell after the bursting membrane has burst .

This enables the cooling medium to be injected into the battery cell on the opposite side of the bursting membrane, in particular only after the thermally broken battery cell has been degassed via the bursting membrane, which can lead to improved cooling of the thermally broken battery cell. A faster and improved cooling of the battery cell can thus be realized, whereby thermal runaway of further battery cells is prevented. In particular, it can also be realized in this way that the cooling medium has to be injected into the thermally broken battery cell with less pressure, since it is not necessary to work against the pressure of the resulting gas in the case of the best membrane.

In particular, this makes it possible to avoid additional valves within the cooling plate, which increase the risk of these valves leaking. Furthermore, the operating pressure within the cooling system can be reduced with the cooling plate. In the case of the countercurrent principle in particular, as carried out in the prior art, the coolant must be injected into the cell against the outflowing gas. The time-delayed injection of the cooling medium according to the invention after the cell has already reduced pressure makes it possible, in a simplified manner, to inject the cooling medium into the damaged battery cell. This is made possible, in particular, in an improved manner, in that the cooling medium is injected from the side opposite the bursting membrane.

In other words, it is provided in particular that the cooling plate with passage openings is used for the passage of gas from the respective battery cell. During thermal runaway, the battery cells can reduce their overpressure through the feedthroughs in the cooling plate. The cooling plate does not contain any valves for this purpose. In addition, the cooling device is used with the cooling medium, which connects all cells to one another and relates to the opposite cell side is located on the bursting membrane in order to be able to carry out a pressure equalization. In the event of a thermal runaway, the thermally runaway battery cell is now cooled with the cooling medium, which prevents the heat from spreading to neighboring cells and these also being caused to thermally runaway. For example, a water-based fluidic media or CO ₂ , NH ₃ or other cooling or extinguishing media can be regarded as the cooling medium. In particular, this enables the susceptibility to errors, such as, for example, susceptibility to leakage, of the system to be reduced. Furthermore, the use of the direct current principle enables the cooling function to be carried out more efficiently. This means that larger battery cells can also be cooled, for example. Furthermore, the cost, the service life and the weight are improved.

According to an advantageous embodiment, the cooling device has a respective ignition capsule assigned to the battery cell, which is arranged between the cooling medium and the respective battery cell and is designed to ignite at a predetermined temperature and / or after a predetermined time and thus establish a connection, in particular a spatial connection between the cooling medium and the interior. In other words, it is provided in particular that the ignition capsule is installed or arranged in the battery cell or on the battery cell. The ignition capsule contains an ignition means and is closed to the outside with at least one metal membrane. The housing of the ignition capsule is made in particular of metal, for example aluminum, nickel or stainless steel, and hermetically shields the interior of the capsule from the interior of the battery cell. The primer is in particular a separate component, in other words a separate component, and can be installed in the battery cell cover using the same method as the bursting membrane. The ignition capsule is triggered in particular with a time delay by the absorption of heat when the battery cell gets out of control. As a result of the warm-up delay, which is adjustable in particular, the primer only opens when the bursting membrane at the bottom of the battery cell has already triggered and the overpressure in the battery cell has been reduced. When the bursting membrane of the primer then opens, the overpressure in the primer also punctures the coolant supply membrane above it. The cooling medium, which is in particular pressurized and which has in particular 1 to 3 bar, flows into the battery cell and evaporates there, whereby the battery cell is cooled. This enables improved cooling of the electrical energy store.

In a further advantageous embodiment, the ignition capsule has a mandrel on a side facing the cooling medium, by means of which a wall to the cooling medium can be pierced. In particular, this is therefore an advantage that the wall to the cooling medium can be pierced in a simplified manner by means of the mandrel. In other words, by means of the primer, which in the present exemplary embodiment can also be designed as a bursting membrane, the mandrel is correspondingly accelerated and can pierce the wall to the cooling medium within the cooling device. Reliable injection of the cooling medium into the interior of the battery cell is thereby achieved.

Furthermore, it has proven to be advantageous if an electrical insulation element and / or a sealing element are formed between a respective battery cell and the cooling device. In particular, due to the seal between the battery cells and the coolant supply, the evaporating coolant, in other words the cooling medium, is forced to find its way out of the battery cell through the already open burst valve, i.e. into the interior of the damaged battery cell, and the bursting membrane on the cell bottom tracks. The battery cell is thus cooled from the side of the cooling device to the side of the bursting membrane. This enables the damaged battery cell to cool down more effectively. The electrical insulation element can in particular prevent a short circuit from occurring between the cooling device and a battery cell housing wall, for example. Reliable operation of the electrical energy store can thus be achieved.

It has also proven to be advantageous if the cooling device is designed as a closed cooling circuit. In other words, the cooling device has a cooling medium provided specifically for the cooling device. This is independent of a cooling circuit of the electrical energy store or of the motor vehicle. In this way, for example, in addition to a pure cooling medium, an extinguishing medium can also be used which is designed to extinguish the battery cell. This enables improved operation of the electrical energy store.

In an alternative, improved embodiment, the cooling device can be designed as an open cooling circuit. In particular, for example, the cooling device can then also be connected to a cooling circuit of the electrical energy store. In other words, it can be provided that an already existing cooling medium within the electrical energy store is used to also supply the cooling device with the cooling medium. This means that the number of components can be reduced and the cooling device can be supplied with the cooling medium in a weight-reduced manner.

In a further advantageous embodiment, the cooling medium is also designed as an extinguishing medium. This makes it possible that, in addition to the pure cooling function, an extinguishing function is also made possible within the battery cell. This enables safe operation of the electrical energy store.

It is also advantageous if the cooling device is arranged between respective electrical conductor elements of the battery cell. In particular, it is thereby made possible that the cooling device can be arranged on the electrical energy store in a space-reduced manner. In particular, the electrical conductor elements are raised from a battery cell housing. The cooling device can then be arranged in a space-saving manner between these raised diverter elements. In particular, a plus pole and a minus pole of the respective battery cell can be viewed as the arrester element.

According to a further advantageous embodiment, the cooling device has at least one metallic flange which is designed to be welded to a battery cell housing of a respective battery cell. This enables simplified assembly of the cooling device. In particular, the cooling device according to the invention can thereby also be arranged on already existing electrical energy stores.

Another aspect of the invention relates to a motor vehicle with an electrical energy store according to the preceding aspect. The motor vehicle is designed in particular as a passenger vehicle. Furthermore, the motor vehicle is designed in particular as an at least partially electrically operated motor vehicle, in particular as a fully electrically operated motor vehicle.

Yet another aspect of the invention relates to a method for cooling an electrical energy store for an at least partially electrically operated motor vehicle during a thermal runaway of a battery cell of the electrical energy store, in which at least two battery cells are arranged on a cooling plate of the electrical energy store, with one during thermal runaway of the battery cells, this battery cell is cooled by means of the cooling plate, whereby a bursting membrane assigned to this battery cell, which is arranged between this battery cell and the cooling plate, is ruptured and a hot gas produced during the thermal runaway is discharged from this battery cell to the cooling plate.

It is provided that a cooling device formed on the cooling plate opposite side of the battery cells, which is coupled to the at least two battery cells, is used to inject a cooling medium into the interior of the thermally broken battery cell after the bursting membrane has burst.

Advantageous embodiments of the electrical energy store are to be regarded as advantageous embodiments of the motor vehicle and of the method. For this purpose, the electrical energy store and the motor vehicle have objective features which enable the method or an advantageous embodiment thereof to be carried out.

Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination, but also in other combinations or on their own.

• 1 eine schematische Draufsicht auf eine Ausführungsform eines elektrischen Energiespeichers;
• 2 eine schematische Seitenansicht einer Ausführungsform einer Batteriezelle;
• 3 eine schematische Schnittansicht einer Ausführungsform einer Kühleinrichtung; und
• 4 ein schematisches Ablaufdiagramm einer Ausführungsform eines Verfahrens.

The invention will now be explained in more detail using a preferred exemplary embodiment and with reference to the drawings. Show it:

• 1 a schematic plan view of an embodiment of an electrical energy store;
• 2 a schematic side view of an embodiment of a battery cell;
• 3 a schematic sectional view of an embodiment of a cooling device; and
• 4th a schematic flow diagram of an embodiment of a method.

Identical or functionally identical elements are provided with the same reference symbols in the figures.

1 shows an embodiment of an electrical energy store in a schematic plan view 10 . The electrical energy storage 10 is designed for an at least partially electrically operated motor vehicle (not shown). In particular, the motor vehicle can also be operated fully electrically. The motor vehicle is designed in particular as a passenger vehicle. The electrical energy storage 10 in particular has at least two battery cells 12th , 14th , 16 , 18th on. In the following exemplary embodiment, the electrical energy store 10 a first battery cell 12th , a second battery cell 14th , a third battery cell 16 and a fourth battery cell 18th on. A respective battery cell 12th , 14th , 16 , 18th again has two arrester elements 20th , 22nd on, being a positive pole 20th and a negative pole 22nd each raised on the battery cells 12th , 14th , 16 , 18th are trained.

In the 1 is especially the electrical energy storage 10 seen in a top view. The 1 in particular shows that the battery cells 12th , 14th , 16 , 18th via a cooling device 24 are coupled to each other.

The 1 thus shows the electrical energy storage 10 for the at least partially electrically operated motor vehicle, with the at least two battery cells 12th , 14th , 16 , 18th , with a cooling plate 26th ( 2 ), on which the at least two battery cells 12th , 14th , 16 , 18th are arranged, between a respective battery cell 12th , 14th , 16 , 18th and the cooling plate 26th at least in some areas a respective bursting membrane 28 ( 2 ) is arranged, which in the event of a thermal runaway 58 one of the battery cells 12th , 14th , 16 , 18th for bursting at a predetermined temperature and for discharging one upon thermal runaway 58 resulting hot gas 30th ( 4th ) from this battery cell 12th , 14th , 16 , 18th to the cooling plate 26th are trained.

It is intended that on one of the cooling plate 26th opposite side 32 of the battery cells 12th , 14th , 16 , 18th the cooling device 24 is formed, which with the at least two battery cells 12th , 14th , 16 , 18th is coupled, wherein the cooling device 24 is designed for this, temporally after the bursting of the bursting membrane 28 a cooling medium 34 in an interior 36 ( 2 ) of the thermally broken battery cell 12th , 14th , 16 , 18th inject.

In the present exemplary embodiment, the second battery cell is in particular 14th , thermally run through. This is particularly due to the dashed battery cell 14th marked.

1 shows in particular that the cooling device 24 can be designed as a closed cooling circuit. In other words, the cooling device 24 one especially for the cooling device 24 intended cooling medium 34 on. This is independent of a cooling circuit of the electrical energy store 10 or the motor vehicle. This allows, for example, in addition to a pure cooling medium 34 an extinguishing medium can also be used, which is used to extinguish the battery cell 12th , 14th , 16 , 18th is trained. This improves the operation of the electrical energy store 10 enables.

Alternatively, the cooling device 24 can also be designed as an open cooling circuit. In particular, for example, the cooling device 24 then on a cooling circuit of the electrical energy store 10 be connected with. In other words, it can be provided that an already existing cooling medium 34 within the electrical energy store 10 the cooling device is also used for this purpose 24 with the cooling medium 34 to supply. As a result, the cooling device can be component-reduced and weight-reduced 24 are supplied with the cooling medium.

Furthermore, the 1 in particular that the cooling device 24 between respective electrical arrester elements 20th , 22nd of the battery cells 12th , 14th , 16 , 18th is arranged.

2 shows an embodiment of a battery cell in a schematic side view 12th , 14th , 16 , 18th . In the present exemplary embodiment, the second battery cell is in particular 14th shown. The battery cell 14th in particular has a battery cell housing 38 on and the interior 36 . Between the arrester elements 20th , 22nd is in particular the cooling device 24 educated. Furthermore, the 2 that in particular between a respective battery cell 12th , 14th , 16 , 18th and the cooling device 24 an electrical insulation element 40 and / or a sealing element 42 is trained. In particular, this can cause a short circuit between the cooling device 24 be avoided. Furthermore, it can be avoided that, for example, the cooling medium 34 from the cooling device 24 can emerge unintentionally.

Furthermore, it can in particular be provided that the cooling medium 34 is also designed as an extinguishing medium. In other words, it can be provided that, in addition to the cooling function, the cooling medium 34 is also designed for deletion.

The 2 also shows that in the interior 36 the second battery cell 14th in the present embodiment a primer 44 is trained. The primer 44 in particular has an ignition means 46 on. The primer 44 can alternatively be arranged in the interior 36 also on the battery cell housing 38 be arranged.

3 shows an embodiment of the cooling device in a schematic sectional view 24 . In particular, shows the 3 that the cooling device 24 a respective one of the battery cells 12th , 14th , 16 , 18th associated primer 44 has, which between the cooling medium 34 and the respective battery cell 12th , 14th , 16 , 18th is arranged and is designed to be at a predetermined temperature T and / or to ignite after a predetermined time and thus a connection, in particular a spatial connection, between the cooling medium 34 and the interior 36 to manufacture. The primer 44 has in particular the ignition means 46 on. The primer 46 For example, a nitrogen-rich organic compound, for example 5-aminotetrazole, in combination with an inorganic oxidizing agent, for example alkali or alkaline earth metal nitrates, cellulose nitrate in combination with nitrate esters of polyols, for example nitroglycerin, or oxygen-rich, nitrogen-free organic compounds, for example citric acid, in Be combination with chlorates or perchlorates. Azides, for example salts of hydrazoic acid, mixed with tetrazene can also be used as ignition agents 46 to be provided.

In particular, the ignition means 46 designed in such a way that it ignites at temperatures greater than 120 degrees Celsius.

Furthermore, the 3 in particular that the primer 44 on one of the cooling medium 34 facing side a thorn 48 has, by means of which a wall 50 to the cooling medium 34 is pierceable.

Furthermore, the 3 that the cooling device 34 at least one metallic flange 52 may have, which for welding to the battery cell housing 38 a respective battery cell 12th , 14th , 16 , 18th is trained.

Furthermore, the 3 in particular that the primer 44 also a rupture disc 54 may have, at which in particular the triggering pressure is greater than that of the bursting membrane 28 the cooling plate 26th . It can also be provided that the primer 44 a thermal lining 56 may have which to adapt the triggering delay of the ignition means 46 after the occurrence of thermal runaway 58 can be used. Thus, for example, a desired time delay can be implemented as a function of the composition of the lining.

4th shows in a schematic view an embodiment of a method for cooling the electrical energy store 10 . In particular, in the 4th a time sequence to see how the electrical energy storage 10 , especially the second battery cell 14th , can be deleted according to the arrangement in the 1 . In a first step S1 thermal runaway occurs 58 the second battery cell 14th . In a second step S2 becomes the bursting membrane 28 burst and the hot gas 30th occurs on the cooling plate 26th out. After the hot gas 30th through the best membrane 28 has leaked, the cooling medium 34 through the primer 44 in the interior 36 the second battery cell 14th introduced. In particular, this takes place from the opposite side of the cooling plate 26th . In the third step S3 then becomes the coolant 34 through the cooling device 24 in the interior 36 brought in. In the fourth step S4 again is the second battery cell 14th cooled and the hot gas 30th almost from the cooling plate 26th disappeared. A thermal runaway 58 of the entire electrical energy storage system 10 is thus prevented.

Overall, the 4th in particular the method for cooling the electrical energy store 10 for the at least partially electrically powered motor vehicle during a thermal runaway 58 one of the battery cells 12th , 14th , 16 , 18th , in the present case using the exemplary embodiment of the second battery cell 14th , the electrical energy storage 10 , at which on the cooling plate 26th of electrical energy storage 10 the at least two battery cells 12th , 14th , 16 , 18th are arranged, with the thermal runaway 58 one of the battery cells 12th , 14th , 16 , 18th this battery cell 12th , 14th , 16 , 18th by means of the cooling plate 26th is cooled, one of these battery cells 12th , 14th , 16 , 18th assigned best membrane 28 , which between the battery cell 12th , 14th , 16 , 18th and the cooling plate 26th is arranged, is brought to the best and thereby a thermal runaway 58 hot gas produced 30th from this battery cell 12th , 14th , 16 , 18th to the cooling plate 26th is discharged.

It is provided that by means of the on the cooling plate 26th opposite side 32 the battery cell 12th , 14th , 16 , 18th trained cooling device 24 , which with the at least two battery cells 12th , 14th , 16 , 18th is coupled, temporally after the bursting of the bursting membrane 28 a cooling medium 34 in the interior 36 the thermally broken battery cell 12th , 14th , 16 , 18th is injected.

Overall, the invention shows emergency cooling of the electrical energy store 10 .

List of reference symbols

10

electrical energy storage

12th

first battery cell

14th

second battery cell

16

third battery cell

18th

fourth battery cell

20th

Positive pole

22nd

Negative pole

24

Cooling device

26th

Cooling plate

28

Bursting membrane

30th

hot gas

32

opposite side

34

Cooling medium

36

inner space

38

Battery cell housing

40

Isolation element

42

Sealing element

44

Primer

46

Ignition means

48

mandrel

50

Wall

52

flange

54

Rupture disc

56

thermal lining

58

thermal runaway

T

specified temperature

S1

first step

S2

second step

S3

Third step

S4

fourth step

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102017212223 A1 [0003]

Claims (10)

Electrical energy store (10) for an at least partially electrically operated motor vehicle, with at least two battery cells (12, 14, 16, 18), with a cooling plate (26) on which the at least two battery cells (12, 14, 16, 18) are arranged , wherein a respective bursting membrane (28) is arranged between a respective battery cell (12, 14, 16, 18) and the cooling plate (26), at least in some areas, which, when one of the battery cells (12, 14, 16, 18) are designed to burst at a predetermined temperature and to discharge a hot gas (30) produced during the thermal runaway (58) from this battery cell (12, 14, 16, 18) to the cooling plate (26), characterized in that on one of the cooling plate (26) opposite side (32) of the battery cells (12, 14, 16, 18) a cooling device (24) is formed which is coupled to the at least two battery cells (12, 14, 16, 18), wherein the Cooling device (24) daz u is designed to inject a cooling medium (34) into an interior space (26) of the thermally broken battery cell (12, 14, 16, 18) after the bursting membrane (28) has burst. Electrical energy storage (10) according to Claim 1 , characterized in that the cooling device (24) has a respective ignition capsule (44) assigned to the battery cell (12, 14, 16, 18), which is located between the cooling medium (34) and the respective battery cell (12, 14, 16, 18) is arranged and designed to ignite at a predetermined temperature (T) and / or after a predetermined time and thus establish a connection between the cooling medium (34) and the interior (36). Electrical energy storage (10) according to Claim 2 , characterized in that the primer (44) has a mandrel (48) on a side facing the cooling medium (34), by means of which a wall (50) for the cooling medium (34) can be pierced. Electrical energy store (10) according to one of the preceding claims, characterized in that an electrical insulation element (40) and / or a sealing element (42) is formed between a respective battery cell (12, 14, 16, 18) and the cooling device (24) . Electrical energy store (10) according to one of the preceding claims, characterized in that the cooling device (24) is designed as a closed cooling circuit. Electrical energy store (10) according to one of the Claims 1 to 4th , characterized in that the cooling device (24) is designed as an open cooling circuit. Electrical energy store (10) according to one of the preceding claims, characterized in that the cooling medium (34) is also designed as an extinguishing medium. Electrical energy store (10) according to one of the preceding claims, characterized in that the cooling device (24) is arranged between respective electrical conductor elements (20, 22) of the battery cells (12, 14, 16, 18). Electrical energy store (10) according to one of the preceding claims, characterized in that the cooling device (24) has at least one metallic flange (52) which is for welding to a battery cell housing (38) of a respective battery cell (12, 14, 16, 18) is trained. Method for cooling an electrical energy store (10) for an at least partially electrically operated motor vehicle during a thermal runaway (58) of a battery cell (12, 14, 16, 18) of the electrical energy store (10), in which the electrical energy store (10) at least two battery cells (12, 14, 16, 18) are arranged, with one of the battery cells (12, 14, 16, 18) this battery cell (12, 14, 16, 18) during thermal runaway (58) is cooled by means of the cooling plate (26), a bursting membrane (28) assigned to this battery cell (12, 14, 16, 18), which is arranged between this battery cell (12, 14, 16, 18) and the cooling plate (26) for Bursting and thereby a hot gas (30) produced during the thermal runaway (58) is discharged from this battery cell (12, 14, 16, 18) to the cooling plate (26), characterized in that by means of a on one of the cooling plates ( 24) opposite Se ite (32) of the battery cells (12, 14, 16, 18) formed cooling device (24), which is coupled to the at least two battery cells (12, 14, 16, 18), a cooling medium after the bursting of the bursting membrane (28) (34) is injected into an interior (36) of the thermally broken battery cell (12, 14, 16, 18).

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