Patent Application
20110232302
The present invention relates to a battery test rig which is used to examine or check different batteries.
The function and load limits of batteries are checked, for example, as part of development and production. However, a considerable potential hazard may result in this case. In particular, in the case of excessive charging or discharging or else in the case of other external environmental influences, for example a temperature increase, gaseous cleavage products, which may result in a pressure increase, may be produced in the event of reactions between the existing battery materials (cathode, anode, electrolyte). Furthermore, exothermic reactions may entail a further supply of heat. Consequently, the battery may be destroyed by an explosion. As a result, work on battery test rigs may be hazardous. It would therefore be desirable to have an improved level of safety, in particular, for the employees working with battery test rigs.
In contrast, the battery test rig according to the invention has the advantage that it is possible to test or examine batteries with an increased level of safety. According to the invention, high-efficiency cooling can be carried out in this case if necessary. This is achieved, according to the invention, by virtue of the fact that the battery test rig comprises a cooling apparatus which is connected to a regulation unit. A sensor device is connected to the regulation unit in order to monitor the battery. If the regulation unit detects that there is a hazard situation, it activates the cooling apparatus in order to cool the battery in order to thus prevent a critical battery state. The inventive external cooling of the battery thus makes it possible, on the one hand, to reduce a temperature of the battery and a pressure inside the battery, with the result that a critical situation can be avoided. The inventive use of the cooling apparatus also makes it possible to safely check research samples of batteries, in particular.
The cooling apparatus preferably comprises a pressure vessel which is connected to a test cell, in which the battery is arranged, via a line. The cooling apparatus also comprises a switching valve which is connected to the regulation unit and is opened in a hazard situation in order to lead a cooling medium stored in the pressure vessel to the battery. As a result, a large area of the battery may be wetted with the coolant, thus resulting in a high degree of cooling efficiency. The pressure vessel may also have a large supply of cooling medium in order to be able to cool the battery for as long as possible.
The cooling apparatus more preferably comprises a nozzle which is arranged in the test cell and makes it possible for the cooling medium to expand in the vicinity of the battery. In this case, the cooling medium is sprayed onto the battery via the nozzle in order to cool the battery over as large an area as possible. In this case, the nozzle is preferably arranged above the battery, such that the cooling medium flows down along the outer periphery of the battery. In this case, the battery is more preferably arranged horizontally in the test cell, with the result that as large an area as possible can be wetted with cooling medium.
According to another preferred refinement of the present invention, the cooling apparatus comprises at least one Peltier unit which is arranged in the test center in order to cool the battery. The Peltier units consist of Peltier elements which are placed flat against one another, the Peltier elements consisting, for example, of two semiconductor ceramics which are connected by metal bridges. If a safety-critical state of the battery to be checked occurs, the Peltier unit is energized, as a result of which one of the semiconductor ceramics is cooled, whereas the other is heated. In this case, the cooling apparatus particularly preferably comprises a multiplicity of Peltier units which are arranged in the form of a pyramid. This makes it possible to achieve a plurality of cooling stages, such that even large temperature differences of up to 70 Kelvin and temperatures below 0° C. can be achieved. In this case, the last stage of the multiplicity of Peltier units is preferably connected to a heat exchanger which transports the waste heat from the test cell.
The sensor device preferably comprises a temperature sensor and/or a pressure sensor and/or a force sensor, in particular a strain gage, and/or a distance sensor. In this case, the sensors are preferably arranged on an outer side of the battery. As a result, a simple structure of the battery test rig is achieved and, in particular, a multiplicity of batteries can be checked in a short time. It is noted that a plurality of different sensors are particularly preferably arranged on the battery. Alternatively, it is naturally also possible to arrange a plurality of identical sensors on a battery to be examined.
The battery test rig preferably also comprises a suction apparatus in order to suction gases or other media from the interior of the test cell. On the one hand, this results in toxic gases, for example, being able to be safely suctioned from the test cell and, on the other hand, avoids a disproportionate pressure increase inside the test cell. A vacuum can also be generated in the test cell as a result.
According to another preferred refinement of the present invention, the battery test rig also comprises a current interruption device, with the result that yet another safety device is present in addition to the cooling apparatus. In a critical state of the battery to be examined, a battery current is interrupted using the current interruption device in order to avoid further function-related heating of the battery.
In this case, the battery test rig according to the invention can be used, on the one hand, in research and development departments, which examine batteries, and may furthermore likewise also be used by battery manufacturers for quality control of the batteries produced. In this case, the battery test rig according to the invention does not have any restriction in terms of the battery to be checked. In particular, research samples, half-cells (electrochemical samples), battery packs, which are composed of modules and have high power levels, or else lithium ion batteries can also be checked.
Preferred exemplary embodiments of the invention are described in detail below with reference to the accompanying drawing, in which:
A battery test rig 1 according to one preferred exemplary embodiment of the invention is described in detail below with reference to
As can be seen from
The battery test rig 1 also comprises a regulation unit 4 and a cooling apparatus 7. A pressure sensor 5 and a temperature sensor 6 are also provided and are fixed to an outer side of the battery 2. The pressure sensor 5 and the temperature sensor 6 are connected to the regulation unit 4 via lines 5a and 6a. In this case, the reference symbol 2a denotes an electrical connection between the battery 2 and the regulation unit 4. The cooling apparatus 7 comprises a pressure vessel 8 in which a cooling medium 9 is arranged under pressure. The pressure vessel 8 is connected to an interior of the test cell 3 via a line 10. In this case, a switching valve 11 which is in the form of a shut-off valve and releases or closes the line 10 is arranged in the line 10. As can be seen from
The reference symbol 14 also denotes a suction apparatus for suctioning gases and/or liquids from the test cell 3 and for generating a vacuum in the test cell.
The operation of the battery test rig 1 in an emergency is as follows in this case. The sensors 5, 6 continuously detect, at predetermined intervals, corresponding sensor values which are supplied to the regulation unit 4. The regulation unit 4 checks the supplied sensor values, for example by means of a comparison with stored values. As soon as a sensor value reaches a predetermined threshold value, the regulation unit 4 determines that there is an emergency and activates the cooling apparatus 7. For this purpose, the switching valve 11 is opened, with the result that the cooling medium 9 can be passed to the nozzle 12 via the line 10. As a result of the sudden expansion of the cooling medium at the nozzle 12, the cooling medium cools and is supplied to the outer side of the battery 2. In this case, it is noted that the cooling medium may be a gas or else a liquid. The suction apparatus 14 is preferably also activated at the same time in order to increase the cooling efficiency by reducing the pressure in the test cell 3. It is also noted that it is possible to monitor not only the battery directly but also a pressure inside the test cell 3, for example. Sensors for measuring a force acting on a battery housing by development of a gas inside the battery can also be provided, for example, which sensors may be fitted to the outer side of the battery 2, for example in the form of strain gages. Alternatively or additionally, expansion of the battery can also be detected in a contactless manner, for example using distance sensors, for example via battery angulation.
A battery test rig with an increased level of safety can therefore be provided according to the invention by the cooling apparatus 7. As a result, critical situations can be detected by the regulation unit 4 when checking batteries and the battery can be cooled using the cooling apparatus 7 or a pressure can be reduced in order to avoid a hazard situation. It is noted in this case that a plurality of cooling apparatuses 7 may naturally also be arranged in order to have redundancy in an emergency. A plurality of cooling apparatuses may also be used to cool a plurality of regions of the battery 2. For example, additional nozzles may be arranged laterally or on the end faces of the battery 2. In this case, the nozzles may be supplied via only one pressure vessel 8 or alternatively may also be respectively supplied with cooling medium via separate pressure vessels.
A battery test rig 1 according to a second exemplary embodiment of the invention is described in detail below with reference to
In contrast to the first exemplary embodiment, the battery test rig 1 in the second exemplary embodiment comprises two cooling apparatuses. Like in the first exemplary embodiment, a first cooling apparatus 7 is formed with a pressure vessel 8, a line 10, a switching valve 11 and a nozzle 12. A second cooling apparatus 17 which comprises a multiplicity of Peltier units 18 and a heat exchanger 19 is also provided. The heat exchanger 19 is arranged in the housing of the test cell 3 and is connected, by its inwardly directed side, to the Peltier units 18. In this case, the Peltier units 18 are constructed in the form of a pyramid and each comprise Peltier elements which are respectively placed flat against one another. The structure in the form of a pyramid results in a multi-stage cooling system, the last stage being connected to the heat exchanger 19. In the exemplary embodiment shown, the second cooling apparatus 17 is connected to one end of the battery 2. Alternatively, however, it is also possible for the second cooling apparatus 17 to only be connected to the battery in an emergency. This can be achieved, for example, in such a manner that the second cooling apparatus 17 is arranged on a linear supply arrangement and, if an emergency is detected, the second cooling apparatus 17 is moved linearly until it is in contact with the battery 2 in order to dissipate heat from the battery. Otherwise, this exemplary embodiment corresponds to the first exemplary embodiment, and so reference can be made to the description given there. It is also noted in this case that only a heat exchanger with a liquid medium or a second cooling apparatus with a cold air stream would alternatively also be possible as the second cooling apparatus. In contrast, however, the use of the Peltier units as the second cooling apparatus 17 has the advantage of a small installation space and a very effective cooling option.
It is also noted that the battery test rig may additionally also comprise a current interruption device in order to interrupt a current generated by the battery 2 in an emergency. This ensures that no additional heat is generated by operating the battery 2.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 042 135.9 | Sep 2008 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2009/059437 | 7/22/2009 | WO | 00 | 5/26/2011 |
