Battery module and use of a propagation protection element

Abstract

A battery module comprising at least one battery cell (2), wherein the battery module (1) further comprises a propagation protection element (3) which is connected in a thermally conductive manner to the battery cell (2) and which is designed in such a way that, when a specific value for a temperature of the at least one battery cell (2) is exceeded, an endothermic process which is being executed within the propagation protection element (3) absorbs heat which is given off by the at least one battery cell (2).

Claims

1. A battery module comprising at least one battery cell (2), a propagation protection element (3) which is connected in a thermally conductive manner to the battery cell (2) and which is configured such that, when a specific value for a temperature of the at least one battery cell (2) is exceeded, an endothermic process executed within the propagation protection element (3) absorbs heat which is given off by the at least one battery cell (2), a temperature sensor (TS) arranged on or within the propagation protection element (3) and configured to identify that the specific value for the temperature has been exceeded, and a control unit (CU) programmed to identify, in response to the temperature sensor (TS) identifying that the specific value for the temperature has been exceeded, that the endothermic process within the propagation protection element (3) has been executed.

2. The battery module according to claim 1, characterized in that the propagation protection element (3) is in direct mechanical contact with the at least one battery cell (2).

3. The battery module according to claim 1, characterized in that the propagation protection element (3) contains a phase-change material.

4. The battery module according to claim 1, characterized in that the propagation protection element (3) comprises a plurality of substances which, when the specific value for the temperature of the at least one battery cell (2) is exceeded, react in an endothermic manner with one another to form at least one further substance.

5. The battery module according to claim 1, characterized in that the propagation protection element (3) comprises at least one substance which, when the specific value for the temperature of the at least one battery cell (2) is exceeded, decomposes in an endothermic manner to form at least two further substances.

6. The battery module according to claim 5, characterized in that the propagation protection element (3) comprises a hydroxide.

7. The battery module according to claim 6 wherein the hydroxide is lithium hydroxide, sodium hydroxide, calcium hydroxide, potassium hydroxide or aluminum hydroxide.

8. The battery module according to claim 6, characterized in that the propagation protection element (3) partially or completely encapsulates the at least one battery cell (2), or in that the at least one battery cell (2) has an encapsulation within which the propagation protection element (3) is accommodated.

9. The battery module according to claim 5, characterized in that the propagation protection element (3) comprises a carbonate.

10. The battery module according to claim 9 wherein the carbonate is calcium carbonate, lithium carbonate, sodium carbonate or magnesium carbonate.

11. The battery module according to claim 9, characterized in that the propagation protection element (3) partially or completely encapsulates the at least one battery cell (2), or in that the at least one battery cell (2) has an encapsulation within which the propagation protection element (3) is accommodated.

12. The battery module according to claim 5, characterized in that the propagation protection element (3) comprises a hydrogen carbonate.

13. The battery module according to claim 12 wherein the hydrogen carbonate comprises sodium hydrogen carbonate.

14. The battery module according to claim 12, characterized in that the propagation protection element (3) partially or completely encapsulates the at least one battery cell (2), or in that the at least one battery cell (2) has an encapsulation within which the propagation protection element (3) is accommodated.

15. The battery module according to claim 5, characterized in that the propagation protection element (3) comprises a hydrate salt.

16. The battery module according to claim 15, characterized in that the propagation protection element (3) partially or completely encapsulates the at least one battery cell (2), or in that the at least one battery cell (2) has an encapsulation within which the propagation protection element (3) is accommodated.

17. A battery module comprising at least one battery cell (2), a propagation protection element (3) which is connected in a thermally conductive manner to the battery cell (2) and which is configured such that, when a specific value for a temperature of the at least one battery cell (2) is exceeded, an endothermic process executed within the propagation protection element (3) absorbs heat which is given off by the at least one battery cell (2), a pressure sensor (PS) arranged within the propagation protection element (3) and configured to identify a change in pressure in the propagation protection element (3), and a control unit (CU) programmed to identify, in response to the pressure sensor (PS) identifying a change in pressure in the propagation protection element (3), that the endothermic process within the propagation protection element (3) has been executed.

18. The battery module of claim 17, wherein the endothermic process produces a gas and wherein the battery module further comprises a degassing valve configured to open when a specific pressure within the propagation protection element is exceeded.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the invention are illustrated in the drawings and described in greater detail in the following description.

(2) In the drawings

(3) FIG. 1 schematically shows a battery module comprising a propagation protection element, and

(4) FIG. 2 schematically shows a profile of a temperature within the propagation protection element over the operating period of the battery module.

DETAILED DESCRIPTION

(5) FIG. 1 schematically shows a battery module 1 which comprises battery cells 2 and propagation protection elements 3.

(6) In this case, the propagation protection elements 3 are thermally conductively connected to at least one battery cell 2 in each case.

(7) In particular, the propagation protection elements 3 are arranged so as to be in direct mechanical contact with the respective battery cells 2.

(8) As a result, heat can be transmitted from the battery cells 2 to the respective propagation protection elements 3.

(9) In this case, the propagation protection elements 3 are formed in such a way that an endothermic process can be executed within the respective propagation protection element 3.

(10) In one embodiment, the battery module comprises a control unit CU which identifies that the endothermic process within the propagation protection element 3 has been executed.

(11) In particular, since the endothermic process is irreversible or the battery cell 2 is no longer functional, identifying the execution of the endothermic process may be advantageous.

(12) In one embodiment, a temperature sensor TS is arranged on the propagation protection element 3 or within the propagation protection element 3 for this purpose, said temperature sensor TS identifying that a specific temperature has been exceeded, wherein the temperature corresponds, in particular, to a temperature starting from which the endothermic process is executed.

(13) In one embodiment, a pressure sensor PS is arranged within the propagation protection element 3 for this purpose, said pressure sensor PS identifying a change in the pressure.

(14) An embodiment of this kind is advantageous particularly in the case of endothermic reactions in which a gas is produced.

(15) Furthermore, in one embodiment, the propagation protection element 3 has a degassing valve DV which opens when a specific pressure prevailing within the propagation protection element 3 is exceeded and therefore discharges gases which are produced in the propagation protection element 3 as the endothermic reaction proceeds.

(16) Heating of the propagation protection element 3 owing to an increase in pressure is prevented in this way.

(17) Identifying opening of the degassing valve DV is used for identifying the execution of the endothermic process.

(18) FIG. 2 schematically shows a profile of a temperature 4 of the propagation protection element 3 over the operating period 5 of the battery module 1.

(19) In this case, the profile shown in FIG. 2 has a first region 61 of the operating period 5, within which first region the temperature 4 of the propagation protection element 3 and therefore approximately also the temperature of the respective battery cell 2 which is arranged in a thermally conductive manner on the propagation protection element 3 are substantially constant.

(20) In particular, in this case, a cooling system, not shown in FIG. 1, of the battery module 1 ensures that the temperature of the battery cells 2 is substantially constant.

(21) Furthermore, the profile shown in FIG. 2 has a second region 62 of the operating period 5, within which second region the temperature 4 of the propagation protection element 3 increases over the operating period 5, this possibly being caused by an increase in the temperature of a battery cell 2 which is thermally conductively connected to the propagation protection element 3.

(22) In particular, in this case, the capacity of the cooling system of the battery module 1 is not sufficient to prevent a further increase in the temperature of the battery cell 2.

(23) In addition, the profile shown in FIG. 2 has a third region 63 of the operating period 5, within which third region the temperature 4 of the propagation protection element 3 is substantially constant over the operating period 5.

(24) In this case, a critical value 64 for the temperature 4 has been exceeded at the transition from the second region 62 to the third region 63, so that an endothermic process is executed within the propagation protection element 3, said endothermic process absorbing heat which is given off by the battery cell 2 which is thermally conductively connected to the propagation protection element 3.

(25) As a result, firstly a further increase in temperature within the propagation protection element 3 and secondly also within the battery cell 2 can be prevented.

(26) Therefore, the battery cell 2 can be transferred back to a non-critical state.

(27) A temperature profile of this kind which is represented by a solid line in FIG. 2 can be formed, for example, using a propagation protection element 3 comprising a phase-change material.

(28) It should be noted at this point that it is additionally also possible that the temperature 4 within the third region 63 decreases over the operating period 5, this being intended to be indicated by the dashed line. A temperature profile of this kind can be formed, for example, by a propagation protection element 3 comprising a plurality of substances which react in an endothermic manner to form at least one further substance or by a propagation protection element 3 comprising at least one substance which decomposes to form two further substances.

(29) It should further be noted at this point that the critical value 64 for the temperature 4 represents the critical value for the propagation protection element 3, wherein the endothermic process is executed within the propagation protection element 3 when the critical value 64 is exceeded.

(30) However, in this case, the critical value 64 also corresponds substantially to the safety-critical value for the battery cell 2 which is thermally conductively connected to the respective propagation protection element 3 since, owing to the thermally conductive arrangement of the propagation protection element 3 on the battery cell 2, the conduction of heat should have only a small influence on a difference between the two temperature values.