LAMINATED FILM FOR PACKAGING OF POUCH-TYPE BATTERY CELLS, POUCH-TYPE BATTERY CELL AND BATTERY

Abstract

The present invention is directed to a laminated film for packaging of pouch-type battery cells, the laminated film comprising a plurality of layers including: a first polymer layer, a second polymer layer, a metal barrier layer disposed between the first polymer layer and the second polymer layer, characterized in that the layers further include a heat spreading layer made of a thermally conductive material, wherein the heat spreading layer is integrated within the laminated film such as to be disposed between the first polymer layer and the second polymer layer.

Claims

1. A laminated film for packaging of pouch-type battery cells, the laminated film comprising a plurality of layers including: a first polymer layer, a second polymer layer, a metal barrier layer disposed between the first polymer layer and the second polymer layer, characterized in that the layers further include a heat spreading layer made of a thermally conductive material, wherein the heat spreading layer is integrated within the laminated film such as to be disposed between the first polymer layer and the second polymer layer.

2. The laminated film of claim 1, wherein the heat spreading layer has a thermal conductivity that is larger than 200 W/(m K), preferably larger than 1000 W/(m K).

3. The laminated film of claim 1, wherein the heat spreading layer is made from a carbon material, in particular a pyrolytic carbon material.

4. The laminated film of claim 1, wherein the heat spreading layer has a thickness between 0.5 μm and 200 μm.

5. The laminated film of claim 1, wherein the heat spreading layer is laminated on both of its opposite sides to adjacent layers of the plurality of layers of the laminated film.

6. The laminated film of claim 1, wherein the first polymer layer is made from polypropylene and/or the second polymer layer is made from polyethylene terephthalate (PET).

7. The laminated film of claim 1, wherein the heat spreading layer is disposed between the metal barrier layer and the first polymer layer.

8. The laminated film of claim 1, wherein the layers further include a nylon layer, preferably made from oriented nylon (ONY).

9. The laminated film of claim 1, wherein the first polymer layer is adapted to form an inner layer of a pouch of a pouch-type battery cell and the second polymer layer is adapted to form an outer layer of a pouch of a pouch-type battery cell.

10. A pouch-type battery cell comprising an electrode assembly, wherein the electrode assembly comprises a cathode, an anode and a separator, and wherein the electrode assembly is accommodated within a pouch made from a laminated film according claim 1.

11. The battery comprising at least one pouch-type battery cell according to claim 10.

12. The battery of claim 11, wherein the battery further comprises a thermal management system adapted to control temperature of the at least one pouch-type battery cell, said thermal management system including active cooling means and/or passive cooling means, wherein said cooling means are preferably provided in direct thermal contact with the head spreading layer of the at least one pouch-type battery cell.

13. The battery of claim 11, wherein the battery is adapted to drive an electric aircraft engine, in particular an engine of an electric vertical takeoff and landing aircraft, wherein the engine is rotatable between a hoover position in which a thrust direction of the engine is substantially parallel to the vertical axis of the aircraft, and a cruise position in which a thrust direction of the engine is substantially parallel to the longitudinal axis of the aircraft.

Description

[0024] The invention will now be further described on the basis of preferred embodiments with reference to the accompanying drawings, in which:

[0025] FIG. 1 shows a schematic cross-section of a laminated film according to an embodiment of the present invention,

[0026] FIG. 2 shows a schematic cross-section of a pouch-type battery cell according to an embodiment of the present invention

[0027] FIG. 3 shows a battery according to an embodiment of the present invention, having a pouch-type battery cell.

[0028] A laminated film according to an embodiment of the present invention is shown in cross-section in FIG. 1 and is generally denoted with reference sign 10. Laminated film 10 comprises a plurality of layers as will be set out in the following. A first polymer layer 12, which is made of polypropylene, in particular a cast polypropylene (CPP), with a thickness of preferably 80 μm, forms an inner layer of the laminated film 10, i.e. a layer facing an electrode assembly 14 of a battery cell, when the laminated film 10 is wrapped around the electrode assembly 14 to form a pouch of a pouch-type battery cell.

[0029] Laminated film 10 further comprises a second polymer layer 16, which may be made from a polyethylene terephthalate (PET), for example with a thickness of 12 μm, and which forms an outer layer of laminated film 10 facing towards an exterior side of a pouch-type battery cell when the laminated film 10 is wrapped around electrode assembly 14.

[0030] An aluminum layer 18, for example with a thickness of 40 μm, is disposed between the first polymer layer 12 and the second polymer layer 16. Aluminum layer 18 serves as a metal barrier layer to provide a barrier against diffusion of air and chemicals between the electrode assembly 14 and the exterior.

[0031] Furthermore, according to a feature of the present invention, a heat spreading layer 20 is disposed between the first polymer layer 12 and the second polymer layer 16, in particular between the first polymer layer 12 and the aluminum layer 18. Heat spreading layer 20 is preferably made from pyrolytic carbon (pyrolytic graphite). In this embodiment, the pyrolytic carbon layer may have a thickness of 5 μm. The heat spreading layer 20 may be attached to its adjacent layers by means of an adhesive 22. In the present embodiment, one side of the heat spreading layer 20 is directly attached via adhesive 22 to the aluminum layer 18, while the opposite side of the heat spreading layer 20 is directly attached via adhesive 22 to the first polymer layer 12. However, in alternative embodiments, one or more additional layers may be disposed between the aluminum layer 18 and the heat spreading layer 20 and/or between the heat spreading layer 20 and the first polymer layer 12.

[0032] Furthermore, an additional nylon layer 24, for example made from oriented nylon (ONY), preferably with a thickness of 15 μm, may be provided in the laminated film 10. In the present embodiment, nylon layer 24 is disposed between the aluminum layer 18 and the second polymer layer 16. In particular, one side of the nylon layer 24 may be directly attached to the second polymer layer 12 via adhesive 22, while the opposite side of nylon layer 24 may be directly attached via adhesive 22 to the aluminum layer 18.

[0033] As described above, all layers of the laminated film 10 are attached to one another via adhesive 22 such as to form a mechanically robust single laminated film 10, which can be further processed and in particular wrapped around the electrode assembly 14 such as to form a pouch to manufacture a pouch-type battery cell. Therein, the thermal spreading layer 20 effectively receives, dissipates and transports heat along the area of the cell for improved thermal control of the cell. The thermal spreading layer 20 is thereby integrated within the laminated film 10 and in particular covered by the first polymer layer 12 such as to be protected against mechanical and chemical impacts. The thickness of the thermal spreading layer may therefore be small enough, such as to not significantly increase the overall weight of the laminated film 10 and thus the pouch-type cell.

[0034] The laminated film 10 may be provided as a suitable strip or web material, for example wound on a reel, such that it can be cut to size for manufacturing pouches for pouch-type battery cells. Alternatively, the laminated film may be provided as pre-cut films ready to be wrapped around an electrode assembly of a specific size.

[0035] FIG. 2 shows a pouch-type battery cell 26 according to an embodiment of the present invention in cross-section. The battery cell 26 comprises the electrode assembly 14 mentioned before in relation with FIG. 1. In a particular example, the electrode assembly 14 may include a first cathode 30, a second cathode 32, an anode 34 disposed between the first cathode 30 and the second cathode 32, a first separator 36 disposed between the first cathode 30 and the anode 34, and a second separator 38 disposed between the anode 34 and the second cathode 32. The electrode assembly 14 is preferably a lithium-ion electrode assembly or a lithium-polymer electrode assembly as known as such in the prior art. The first and second cathodes 30, 32 usually each comprise a current collector and cathode material attached to the current collector, e.g. deposited onto the current collector. Likewise anode 34 usually comprises a current collector and anode material attached to the current collector, e.g. deposited onto the current collector.

[0036] The electrode assembly 14 is accommodated within a pouch 40 made from one or more laminated films according to the present invention, in particular one or more laminated films 10 as described with reference to FIG. 1. Preferably, the electrode assembly 14 is sealed in between two layers of laminated film 10 (i.e. between two laminated films 10). The pouch 40 is thus sealed and preferably also evacuated, such as to protect the electrode assembly 14 and avoid diffusion of gases or liquids between the electrode assembly 14 and the exterior.

[0037] Tab connectors 28 electrically connected to the electrodes of the electrode assembly 14, especially to the respective current collectors of the anode and the cathodes, in particular negative tab connectors 28 contacting the current collectors of the cathodes 30, 32 and a positive tab connector 28 contacting the current collector of the anode 34, are provided such as to penetrate the pouch 40 to reach the exterior of the pouch and to allow electrical connection of the battery cell 26.

[0038] FIG. 3 shows a battery 42 according to an embodiment of the present invention. Battery 42 comprises a plurality of pouch-type cells 26, each having a pouch 40 from a laminated film 10 according to the present invention, for example a laminated film 10 as described above with reference to FIG. 1. In particular, each of the cells 26 may be configured as described above with reference to FIG. 2.

[0039] The battery cells 26 are stacked in parallel to one another such as to form a cell stack. To maintain mechanical integrity of the cell stack, battery 42 comprises a frame or housing 44 holding the cells 26 in position and allowing handling of battery 42 as a single unit. Furthermore, battery 42 comprises electric connection means 46 for connecting all cells 26 in parallel or in series, depending on the required characteristics of the battery, thus suitably connecting the contact tabs 28 of the cells 26 together and to battery terminals 48.

[0040] In addition, battery 42 may comprise a thermal management system 50, which includes a heat conductor 52, which is in direct contact with the pouches of all cells 26, and a cooling device 54 for cooling the heat conductor. The heat conductor may be a metal strip or a metal bar. The cooling device 54 may be an active cooling device such as a fan, a heat exchanger, etc., or a passive cooling device such as a plurality of cooling ribs. Alternatively, heat conductor 52 may be thermally connected to an external heat sink to transport heat away from battery 42.

[0041] In addition, the thermal management system 50 may comprise means for monitoring and controlling the temperature, for example a temperature sensor or electronics to control an active cooling device depending on the measured temperature.

[0042] In operation, heat generated within the electrode assemblies of the battery cells 26 will effectively be dissipated and transported through the heat spreading layer 20 integrated within the pouches of the cells 26 such as to achieve not only a homogeneous temperature distribution across the area of each cell but also to efficiently transport heat away from the cell, in particular towards cooling means of the battery, such as the thermal management system 50 shown in FIG. 3. Therefore, overheating of the battery can effectively be avoided even at high energy output. This allows designing batteries for challenging requirements such as for driving electric vehicles, in particular electric aircrafts. [0043] 10 . . . laminated film [0044] 12 . . . first polymer layer [0045] 14 . . . electrode assembly [0046] 16 . . . second polymer layer [0047] 18 . . . aluminum layer [0048] 20 . . . head spreading layer [0049] 22 . . . adhesive [0050] 24 . . . nylon layer [0051] 26 . . . pouch-type battery cell [0052] 28 . . . contact tabs [0053] 30 . . . first cathode [0054] 32 . . . second cathode [0055] 34 . . . anode [0056] 36 . . . first separator [0057] 38 . . . second separator [0058] 40 . . . pouch [0059] 42 . . . battery [0060] 44 . . . frame [0061] 46 . . . electric connection means [0062] 48 . . . battery terminals [0063] 50 . . . thermal management system [0064] 52 . . . head conductor [0065] 54 . . . cooling device