Pouch cell assembly

Abstract

Pouch cell assembly with at least one pouch cell, the pouch cell assembly having at least one pressure-sensitive sensor film, in particular a pressure-sensitive conductive film (pressure-sensitive conductive sheet), which surrounds or delimits at least certain portions of the pouch cell in such a way that inflation of the pouch cell has the effect of compressing the sensor film and thereby changing an electrical resistance of the sensor film.

Claims

1-11. (canceled)

12. A pouch cell assembly comprising: at least one pouch cell; at least one pressure-sensitive sensor film surrounding or delimiting at least certain portions of the at least one pouch cell in such a way that inflation of the at least one pouch cell compresses the sensor film so as to change an electrical resistance of the sensor film.

13. The pouch cell assembly as recited in claim 12 further comprising a rigidly formed frame, the at least one sensor film being supported on one side against the frame and against the pouch cell on an other side.

14. The pouch cell assembly as recited in claim 12 further comprising a pressure equalizing element sandwiched between the pouch cell and the at least one sensor film.

15. The pouch cell assembly as recited in claim 12 wherein the at least one sensor film includes a plurality of sensor films.

16. The pouch cell assembly as recited in claim 12 wherein the at least one sensor film is part of an aluminum composite film, the pouch cell being welded into the aluminum composite.

17. The pouch cell assembly as recited in claim 12 further comprising a sensor circuit, a compressing of the sensor film detectable by the sensor circuit.

18. The pouch cell assembly as recited in claim 17 wherein the sensor circuit is enclosed by the pouch cell assembly.

19. The pouch cell assembly as recited in claim 12 further comprising a control circuit interrupting or reducing drawing of current from the pouch cell assembly or the at least one pouch cell if the sensor circuit has detects compressing of the sensor film.

20. The pouch cell assembly as recited in claim 17 wherein the control circuit is enclosed by the pouch cell assembly.

21. The pouch cell assembly as recited in claim 12 wherein the at least one pouch cell includes a plurality of pouch cells surrounded or delimited in each case by one of the at least one sensor film.

22. The pouch cell assembly as recited in claim 12 wherein the at least one pouch cell includes a plurality of pouch cells, the at least one sensor film including a common sensor film assigned to the plurality of pouch cells

23. The pouch cell assembly as recited in claim 12 wherein the at least one pressure-sensitive sensor film is a pressure-sensitive conductive film.

24. A rechargeable battery pack of an electric hand-held power tool comprising the pouch cell assembly as recited in claim 12.

25. A method comprising employing a sensor film as a pouch film of a pouch cell assembly.

26. The method as recited in claim 25 wherein the sensor film is being part of an aluminum composite film.

27. The method as recited in claim 25 wherein the sensor film is a pressure-sensitive conductive film.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Further advantages can be found in the following description of the figures. Various exemplary embodiments of the present invention are illustrated in the figures. The figures, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to form useful further combinations.

[0020] In the figures, identical and similar components are denoted by the same reference signs. In the figures:

[0021] FIGS. 1A), 1B) and 1C) show a first preferred exemplary embodiment of a pouch cell assembly according to the invention;

[0022] FIG. 2 shows a second preferred exemplary embodiment of a pouch cell assembly according to the invention;

[0023] FIG. 3 shows a third preferred exemplary embodiment of a pouch cell assembly according to the invention; and

[0024] FIG. 4 shows a fourth preferred exemplary embodiment of a pouch cell assembly according to the invention.

DETAILED DESCRIPTION

[0025] A first preferred exemplary embodiment of a pouch cell assembly 100 according to the invention is illustrated in FIGS. 1A), 1B) and 1C). As can be seen in FIGS. 1A) and 1B), the pouch cell assembly 100 has a plurality of pouch cells 10, 10′, 10″, 10″′. FIG. 1A) shows the pouch cells 10, 10′, 10″, 10′″ in the normal state, i.e. they are not inflated, or at most very little. FIG. 1B) on the other hand shows the pouch cells 10, 10′, 10″, 10′″ in the undesired inflated state (with respect to the stacking direction SR). The pouch pouch cells 10, 10′, 10″, 10″′ have in each case a plurality of individual cells 1, which are stacked here in a sandwich-like manner.

[0026] By way of example, the pouch cell assembly 100 is part of a rechargeable battery pack 200 of an electric hand-held power tool 300, which is illustrated in a simplified form in FIG. 1C).

[0027] According to the invention, the pouch cell assembly 100 has at least one pressure-sensitive sensor film 20, which is provided here by way of example as a pressure-sensitive conductive film (pressure-sensitive conductive sheet). At least certain portions of the uppermost pouch cell 10 are delimited by the sensor film 20, so that inflation of the pouch cell 10 has the effect of compressing the sensor film 20 in the stacking direction SR. The pouch cell assembly 100 has a rigidly formed frame 30, the sensor film 20 being supported on the one hand against the frame 30 and on the other hand against the uppermost pouch cell 10. The lowermost pouch cell 10′″ is likewise supported against the frame 30. The rigidly formed frame consequently forms a “counter stop”, so that any pressure introduced into the sensor film 20 from a swelling pouch cell 10, 10′, 10″, 10′″ is intensified. In the present case, the pouch cell assembly 100 therefore has a plurality of pouch cells 10, 10′, 10″, 10′″, to which the common sensor film 20 is assigned.

[0028] The introduction of pressure into the sensor film 20 causes an electrical resistance of the sensor film 20 to change. The sensor film 10 has a lower sheet resistance in the compressed state (FIG. 1B) than in the non-compressed state (FIG. 1A). The sheet resistance Wnk in the non-compressed state Znk is greater than the sheet resistance Wko in the non-compressed state Zko.

[0029] The pouch cell assembly 100 is assigned a sensor circuit 40, by means of which compressing of the sensor film 20 can be detected. The sensor circuit 40 is in this case designed to evaluate electrically a change in sheet resistance of the sensor film 40, the sensor film 40 having a lower sheet resistance Wko in the compressed state (FIG. 1B) than in the non-compressed state (FIG. 1A).

[0030] The pouch cell assembly 100 is likewise assigned a control circuit 50, which interrupts or reduces drawing of current from the pouch cell assembly 100 or the pouch cell 10 if the sensor circuit 40 has detected compressing of the sensor film 20. The control circuit 50 becomes active if the sheet resistance of the sensor film 40 goes below a prespecified threshold value.

[0031] A second preferred exemplary embodiment of a pouch cell assembly 100 according to the invention with a sensor film 20 is illustrated in FIG. 2. Certain portions of the pouch cell 10 are delimited by the sensor film 20, so that inflation of the pouch cell 10 has the effect of compressing the sensor film 20 in the stacking direction SR. In order to ensure even pressure on the surface OF of the pouch cell 10, a pressure equalizing element 70 is provided, arranged in a sandwich-like manner between the pouch cell 10 and the sensor film 20, the sensor film 20 likewise being embedded in the pressure equalizing element 70. By way of example, the pressure equalizing element 70 is provided as a pressure equalizing film 71.

[0032] Also in the case of the exemplary embodiment of FIG. 2, the pouch cell assembly 100 has a rigidly formed frame 30, the sensor film 20 being supported on the one hand against the frame 30—this being indirectly by way of the pressure equalizing element 70—and on the other hand against the pouch cell 10.

[0033] A third preferred exemplary embodiment of a pouch cell assembly 100 according to the invention is illustrated in FIG. 3. In FIG. 3, the pouch cell 10 is illustrated in a plan view. As can be seen in FIG. 3, a number of sensor films 20, 20′, 20″, 20′″ of different sizes and in different positions are provided on the surface OF of the pouch cell 10. This is in order to obtain detailed information concerning a distribution of pressure on the surface OF of the pouch cell 10. All of the sensor films 20, 20′, 20″, 20′″ are electrically connected to a sensor circuit 40, by means of which compressing of the sensor film 20 can be detected. The sensor circuit 40, which is designed to evaluate electrically a change in sheet resistance of the sensor film 40, is in turn connected to a common control circuit 50, by way of which the pouch cell 10 can be deactivated as and when required.

[0034] A fourth preferred exemplary embodiment of a pouch cell assembly 100 according to the invention with at least one pouch cell 10 is illustrated in FIG. 4. The pouch cell 1 has for its part a plurality of individual cells 1, which are stacked here in a sandwich-like manner. The individual cells 1 are welded into an aluminum composite film 90—illustrated in FIG. 4 by dashed lines. Likewise provided is a sensor film 20, which by way of example is provided as a pressure-sensitive conductive film (pressure-sensitive conductive sheet) and is integrated in the aluminum composite film 90 itself. By way of example, here the aluminum composite film 90 is a polyamide-aluminum-polypropylene composite film, with a carbon black coating applied to the polypropylene layer, providing the effect of the pressure dependence of the sheet resistance of the sensor film 20. The aluminum composite film 90 with an integrated sensor film 20 defined a common pouch film 95. Detection of the sheet resistance of the sensor film 20 takes place by way of the sensor circuit 40. By means of the control circuit 50, a desired action can be brought about, for example reducing drawing of current from the pouch cell assembly 100.

[0035] FIG. 4 consequently shows the use of a sensor film 20, in the form of a pressure-sensitive conductive film (pressure-sensitive conductive sheet), as a pouch film 95 of a pouch cell assembly 100, the sensor film 20 being part of an aluminum composite film 90.

LIST OF REFERENCE SIGNS

[0036] 1 Individual cell [0037] 10, 10′, 10″, 10′″ Pouch cells [0038] 20, 20′, 20″, 20′″ Sensor films [0039] 30 Frame [0040] 40 Sensor circuit [0041] 50 Control circuit [0042] 70 Pressure equalizing element [0043] 71 Pressure equalizing film [0044] 90 Aluminum composite film [0045] 95 Pouch film [0046] 100 Pouch cell assembly [0047] 200 Rechargeable battery pack [0048] 300 Electric hand-held power tool [0049] OF Surface [0050] SR Stacking direction [0051] Wnk Sheet resistance in the non-compressed state [0052] Wko Sheet resistance in the compressed state [0053] Znk Non-compressed state [0054] Zko Compressed state