Battery module and method for operating the battery module

Abstract

The present invention relates to a battery module having at least one battery cell (14) and a temperature control device (20, 22) for temperature control of the at least one battery cell (14), wherein the temperature control device (20, 22) includes a Peltier element (20) and / or a heat pipe (22).

Description

Technical field

[0001] The invention relates to a battery module, a method for operating the battery module, and its use. Background art

[0002] Common battery modules include a single battery cell or multiple battery cells electrically connected together. To provide greater electrical power, multiple battery modules can be connected to each other to form a battery pack or a battery system. In particular, lithium-ion or lithium-polymer battery cells generate heat during operation due to electrochemical conversion processes, mainly when rapidly discharging or consuming energy. The higher the effective power of the corresponding battery module, the greater the heat released during operation and the higher the importance of the corresponding effective and active thermal management system. Through the thermal management system, the battery cells of the corresponding battery module can be cooled or heated as needed.

[0003] The optimal operating temperature of lithium-ion battery cells is in the range of approximately 5 - 35°C. From an operating temperature of 40°C onwards, the service life of such lithium-ion battery cells typically decreases significantly. Therefore, in order to achieve a long service life of such battery cells, sufficient thermal regulation of the battery cells is required. It should be noted that such lithium-ion battery cells are kept below 40°C in a thermally non-critical state in as many operating states as possible. In addition, it is desirable to keep the temperature gradient between the individual battery cells of the battery module small in order to achieve uniform aging of the battery cells installed in the battery module.

[0004] Today, heating or heat dissipation of battery modules is mainly carried out on the basis of liquid temperature regulation implemented, for example, with a water / ethylene glycol mixture. The battery module itself or the battery constructed accordingly usually has a cooling plate, and the corresponding cooling medium is supplied to the cooling plate through channels. The process of supplying the corresponding cooling medium to the cooling plate is usually achieved through hose connections and corresponding additional components in the cooling circuit. According to the prior art, heat dissipation of the corresponding battery is carried out through a low-temperature circuit with a heat carrier leading to ambient air or, as an alternative, through the air-conditioning circuit of a vehicle containing a refrigerant. Often, both feasible solutions are utilized and the corresponding cooling circuit is switched via a valve.

[0005] The feed temperature of these cooling circuits should generally be considered to be in the range of approximately 25 - 35 °C. Thus, the cooling effect of such a system is based on the temperature difference between the battery cells to be cooled and the cooling medium of the cooling system. The low-temperature circuit usually has a front radiator, which ensures direct heat transfer to the ambient air, while heat rejection to the vehicle's air-conditioning circuit is carried out by means of a so-called chiller. In order to heat the battery, for example, at cold external temperatures, such a cooling circuit contains additional components, such as a continuous heater or a heating film, which ensure the corresponding heating of the cooling medium.

[0006] As an alternative feasible solution for the temperature control of the battery, from JP 2013 157295 and US2016 / 0372806, a battery system is known respectively, the temperature control of which is based on a cooling plate through which a cooling medium flows through, and the cooling plate is correspondingly temperature-controlled by means of Peltier elements. Summary of the Invention

[0007] According to the present invention, there is provided a battery module, a method for operating the battery module, and its use.

[0008] The battery module according to the present invention has at least one battery cell, in particular a lithium-ion or lithium-polymer battery cell, and a temperature control device. The temperature control device is used to control the temperature of the at least one battery cell not only in terms of heating but also in terms of cooling. According to the present invention, at least one Peltier element or at least one heat pipe in the form of a heating pipe is provided as the temperature control device inside the battery module. Here, a "Peltier element" refers to a thermoelectric element, which causes heat transport when passing an electric current or causes the generation of an electric current based on a temperature difference by utilizing the Peltier effect or the Seebeck effect. In addition, a "heat pipe or heating pipe" refers to a generally metallic container that contains a hermetically sealed space filled with a vaporizing medium, and the vaporizing medium vaporizes when the temperature increases and condenses again in the colder region of the heating pipe. This causes heat transport inside the heat pipe.

[0009] Further advantageous embodiments of the present invention are the subject of the preferred embodiments.

[0010] Therefore, it is advantageous that at least one Peltier element or heat pipe, which is provided as a temperature control device in the battery module, is in physical and thermally conductive contact with at least one single cell of the battery module on one side, but on the opposite side is in physical or thermally conductive contact with a cooling plate, for example, for discharging excess heat, and the cooling plate can be flowed through by a cooling medium, for example. This embodiment ensures on the one hand effective heat dissipation or heating for at least one single cell of the battery module, but on the other hand ensures that the heat transported by means of the Peltier element or heat pipe is sufficiently transported into or discharged from the battery module.

[0011] In a particularly advantageous embodiment of the invention, not only a plurality of Peltier elements but also a plurality of heat pipes are provided as the temperature control device of the battery module. These Peltier elements and heat pipes are arranged, for example, in a planar and alternating manner for the purpose of temperature control inside the battery module, such that the respective Peltier elements and heat pipes are in thermally conductive physical contact not only with the single cells to be cooled but also with the cooling plates provided for heat dissipation.

[0012] Furthermore, a method for operating the battery module according to the invention is the subject of the invention. The method is based on the fact that, in principle, heating of at least one single cell of the battery module is carried out by means of a Peltier element. In addition or as an alternative, it is provided that the at least one Peltier element is also provided for the purpose of cooling inside the battery module. This process is advantageously carried out if the temperature of the at least one single cell is above the operating temperature of the heat pipe also provided in the battery module.

[0013] The advantage of this method is based on the fact that Peltier elements can be used more effectively for the heating purpose of single cells than heat pipes. In addition, when applying this method, the following view is taken into account, that is, in a corresponding design, a heat pipe can only operate up to a maximum temperature at which the cooling medium provided inside the heat pipe is completely in the gas phase and thus can no longer transport heat from the single cell to the cooling plate. In this temperature range, which may be determined, for example, from a temperature of about 35°C, cooling is carried out only by means of the at least one Peltier element at a higher temperature then.

[0014] Furthermore, it is advantageous to use a combination consisting of at least one Peltier element and at least one heat pipe as the temperature control device of the battery module, wherein when the operating temperature of the at least one battery cell is below the maximum operating temperature of the at least one heat pipe, excess heat is mainly or only discharged or the battery cell is cooled by the heat pipe, while the at least one Peltier element is in a cut-off state or in a state where its effective power is reduced at these temperatures.

[0015] The advantage of this measure is that when the operating temperature of the at least one battery cell corresponds to the operating range of the at least one heat pipe, it is in principle possible to have a thermal short circuit between the Peltier elements while using the Peltier elements. For this reason, the Peltier elements are cut off or their power is significantly reduced in the following temperature range (in which heat can be exported by the at least one heat pipe), so that heat is mainly or completely transported out of the at least one battery cell by the at least one heat pipe.

[0016] Furthermore, it is advantageous that the battery module has a control device which is set up to carry out the operating method described above. In this way, appropriate cooling or heating measures for the at least one Peltier element or the at least one heat pipe can be achieved according to the operating temperature of the at least one battery cell.

[0017] The battery module according to the invention or the method according to the invention for operating the battery module can advantageously be used in electrically driven motor vehicles, such as battery electric vehicles (BEV), hybrid electric vehicles (HEV) or plug-in hybrid vehicles (PHEV), and in stationary energy storage devices for storing regeneratively generated energy, for example, and in household repair equipment operated with a storage battery and in household appliances. Description of the Drawings

[0018] Embodiments of the invention are shown in the drawings and are explained in detail in the description of the drawings. Among them:

[0019] Figure 1 A schematic cross-sectional view of a battery module according to the invention according to a first embodiment is shown; and

[0020] Figure 2 A schematic diagram of a method for operating a battery module according to the invention according to Figure 1 is shown. Detailed Description of the Invention

[0021] In Figure 1The battery module 10 according to the invention is shown. Such a battery module includes at least one, preferably a plurality of, battery cells 14 inside a battery module housing 12. The battery cells 14 are in physical and thermally conductive contact with a heat distribution plate 18, for example, via respective bottom surfaces 16a of respective battery cell housings 16. The heat distribution plate 18 is particularly used for temperature equalization between the battery cells 14 and also for heating or discharging heat from the battery cells 14. The heat distribution plate 18 is also in physical and thermally conductive contact with one or more Peltier elements 20 and with one or more heat pipes 22 in the form of heating pipes on its large surface facing away from the battery cells 14.

[0022] The at least one Peltier element 20 or at least one heat pipe 22 is used for temperature regulation or heat transfer or heat discharge between the heat distribution plate 18 and a cooling plate 24, and the cooling plate is also arranged in physical and thermally conductive contact with the Peltier element or the heat pipe on the opposite side of the at least one Peltier element 20 or at least one heat pipe 22. The cooling plate 24 is, for example, flowed through by a particularly liquid cooling medium and is fluidly connected via a connection (not shown) to a cooling system or a heating system external to the battery module 10. Figure 1 in a joint not shown and is fluidly connected to a cooling system or a heating system external to the battery module 10.

[0023] In Figure 2 is schematically shown a method for operating a battery module according to the invention as per Figure 1 Same reference numerals denote the same components as in Figure 1 in.

[0024] The operating method according to the invention is based on the fact that: in a first method step 60, the temperature of at least one of the battery cells 14 and / or the interior space of the battery module 10 is detected. In a second method step 62, the detected operating temperature is assigned to a temperature range. If the operating temperature is within a first temperature range, which is below the temperature range to be achieved for the battery cells 14 or the battery module 10, then in a third method step 64, the battery cells 14 or the battery module 10 are heated.

[0025] This is preferably done by activating the at least one Peltier element 20 with a heat flow direction directed towards at least one cell 14. After a predetermined period of time, the first method step 60 is repeated to determine the operating temperature of the cell 14 or the battery module 10, and thus the method according to the invention is restarted. If the assigned operating temperature in the second method step 62 lies within a second temperature range which, on the one hand, corresponds to the desired temperature range for the operation of the cell 14 or the battery module 10 and at the same time also corresponds to the possible operating temperature of the at least one heat pipe 22, then in an alternative third method step 66 the cell 14 or the battery module 10 is cooled by means of the at least one heat pipe 22 and the Peltier element 20, which was still activated during this period, is switched off.

[0026] After a predeterminable period of time, the process also returns here to the first step 60 of temperature detection of the cell 14 or the battery module 10 and thus the method is restarted.

[0027] If in the second method step 62 the currently present operating temperature of the cell 14 or the battery module 10 is assigned to a temperature range above the temperature range for operating the at least one heat pipe 22, then in a further alternative third method step 68 heat dissipation of the cell 14 or the battery module 10 is induced with the at least one Peltier element 20 activated, wherein, compared to method step 64, the direction of the heat flow is reversed by changing the polarity of the current on the Peltier element 20. Here too, after a predeterminable period of time, the temperature of the cell 14 or the battery module 10 is checked again in the first method step 60 and thus the method according to the invention is restarted.

[0028] The battery module 10 for implementing the method comprises, for example, a control unit (not shown) which is in a connection for conducting measurement signals with temperature elements at or in the cell 14 or at or in the battery module 10 and at the same time is in a connection for conducting control signals with the at least one Peltier element 20 and, if necessary, is in a control-technical connection with the fluid connection of the battery module 10, which fluid connection is in a connection for guiding fluid with the cooling plate 24. Figure 1 ​

Claims

1. A method for operating a battery module having at least one battery cell (14) and a temperature control device (20, 22) for temperature control of the at least one battery cell (14), the temperature control device (20, 22) comprising at least one Peltier element (20) and at least one heat pipe (22), characterized in that, Heating of at least one single cell (14) of the battery module (12) is carried out by means of at least one Peltier element (20) in physical thermally conductive contact with the at least one single cell (14), and cooling of the at least one single cell (14) is carried out by the at least one Peltier element when the temperature of the at least one single cell (14) is above the operating temperature of at least one heat pipe (22) present in the battery module (12), and cooling of the at least one single cell (14) is carried out only or mainly by the at least one heat pipe (22) when the temperature is below the maximum operating temperature of the at least one heat pipe (22) used, and at the same time the at least one Peltier element (20) is switched off or its effect is reduced.

2. The method according to claim 1, characterized in that, The at least one Peltier element (20) and / or the at least one heat pipe (22) are arranged in physical thermally conductive contact with the single cell (14) via a heat distribution plate (18).

3. The method according to claim 1 or 2, characterized in that, The at least one Peltier element (20) and / or the at least one heat pipe (22) are in physical contact with a cooling plate (24) through which a coolant flows on the side facing away from at least one single cell (14).

4. The method according to claim 1 or 2, characterized in that, The at least one single cell (14) is in thermally conductive contact with the at least one Peltier element (20) and / or with the at least one heat pipe (22) via the bottom surface (16a) of the single cell housing (16).

5. The method according to claim 3, wherein As a temperature control device, a plurality of Peltier elements (20) and a plurality of heat pipes (22) are used, and these Peltier elements and heat pipes are arranged alternately in a planar manner with respect to each other, such that not only the Peltier elements (20) but also the heat pipes (22) are in physical thermally conductive contact with the at least one single cell (14) and in physical thermally conductive contact with the cooling plate (24).

6. The method according to claim 1 or 2, characterized in that, A control device for operating the battery module is provided, and the control device is configured to implement the method according to claim 1 or 2.

7. Use of the method according to any one of claims 1 to 6 in a battery for an electrically operated vehicle, in a stationary energy storage device for electrical energy, in a household repair device operated with a storage battery, or in a household appliance.

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