DE102022200433A1 - Battery and method of operating a battery - Google Patents

Abstract

A battery (2) is specified which has two poles (4) for electrical connection, which has at least one cell (8), which has a cell housing (10) and at least one terminal (12), which has a current path (14) which leads from inside the cell (8) via the terminal (12) to one of the two poles (4), which has a thermoelectric element (18) which is attached to the current path (14). A method for operating the battery (2) is also specified.

Description

The invention relates to a battery, in particular for supplying power to an electric drive of an electric or hybrid vehicle. The invention also relates to a method for operating a corresponding battery.

A battery is used, for example, in an electric or hybrid vehicle, where it is used to supply energy to an electric drive of the vehicle. Such a battery regularly provides a voltage in the range of roughly 100 V to 1000 V and a current of several amperes. To this end, the battery typically has a number of cells which are suitably connected to one another in order to obtain a desired voltage and a desired current.

The battery is, for example, a secondary cell based on Li-ion and can then be charged and discharged repeatedly. Both when charging and discharging the battery, waste heat is regularly generated, which should be dissipated by suitable cooling in order to avoid damage to the battery. A battery with a large number of cells for providing a high voltage is regularly a complex component with a large number of components, so that the cooling for such a battery is correspondingly demanding.

Against this background, it is an object of the invention to improve the temperature control of a battery. For this purpose, a suitable battery and a method for its operation are to be specified.

The object is achieved according to the invention by a battery having the features according to claim 1 and by a method having the features according to claim 10. Advantageous refinements, developments and variants are the subject matter of the dependent claims. The statements made in connection with the battery also apply to the method and vice versa. If steps of the method are described below, preferred configurations for the battery result from the fact that it is designed to carry out one or more of these method steps. The object is also achieved in particular by a cell for such a battery. The statements on the battery also apply analogously to such an individual cell and vice versa.

A core concept of the invention is the use of at least one thermoelectric element within a battery, preferably even within a cell of the battery. The use of a thermoelectric element has various advantages: Firstly, active cooling is possible in a targeted manner at certain points within the battery, especially at so-called hot spots, where a particularly large or above-average amount of heat is generated during operation. Secondly, active heating is also possible, which is particularly advantageous in the case of a battery for a vehicle. Thirdly, energy can also be generated with a thermoelectric element, i.e. the waste heat generated by the battery is converted into electrical energy by means of the thermoelectric element and then preferably used to charge the battery.

The battery is preferably a secondary cell, in particular a Li-ion battery. The battery is preferably designed for use in an electric or hybrid vehicle and provides a suitable voltage and a suitable current for this purpose, preferably a voltage in the range from 100 V to 1000 V and/or a current of several amperes. The battery is suitably used in a vehicle electrical system of a vehicle for the electrical supply of an electric drive for moving the vehicle. Alternatively, the battery is stationary storage.

The battery has two poles for electrical connection, e.g. to a vehicle electrical system. The two poles protrude in particular from a housing of the battery and represent an electrical connection of the battery. The battery also has at least one cell, preferably even several cells, e.g. 10 to 200 cells. The battery is therefore also referred to as a battery module. The cell has a cell housing and at least one, preferably two, terminals. The terminals are used for the electrical connection of the cell. In the present case, a cell with two terminals is assumed without loss of generality. If only one terminal is described below, advantageous configurations result from the fact that the respective statements are applied analogously to a second terminal of the cell, although this is not mandatory.

A respective terminal is either a separate part of the cell and then formed separately from the cell housing and is in particular electrically insulated from it, or a part of the cell housing, in particular a cover or generally a side wall or partial wall of the cell housing. In the last-mentioned configuration, the cell housing itself preferably serves as one of the poles of the cell and is then accordingly completely or partially a current-carrying part of the cell. The other pole is then expediently formed by a terminal which is designed separately and electrically isolated from the cell housing. Accordingly, a combination of the two is also provided mentioned configurations is advantageous, so that then one of two terminals of the cell is passed through the cell housing and the other of the two terminals is formed as a part of the cell housing.

In the case of a cell with two terminals, regardless of whether each is formed separately or as part of the cell housing, different spatial arrangements of the terminals relative to one another are suitable. An embodiment is preferred such that the two terminals are arranged on opposite sides of the cell. However, other configurations are also suitable, in particular a configuration in which the two terminals are arranged on the same side of the cell.

The battery also has a current path which leads from inside the cell via the terminal to one of the two poles (the battery). The current path consists in particular of several conductors. The pole and the terminal are each a conductor and therefore part of the current path. Further conductors of the current path are, each optionally, one or more conductors for connecting the pole and the terminal, one or more conductors for connecting the terminals of several cells, a conductor within the cell for connecting the terminal with a cell stack of the cell. The cell stack is, for example, a single sheet stack, a z-folded stack, a coil or the like, and the statements made here apply regardless of the exact design and configuration of the cell stack.

The battery further includes a thermoelectric element attached (i.e., thermally connected) to the current path, particularly for heat exchange of the current path with the thermoelectric element. Optionally and depending on the configuration, the thermoelectric element is also electrically connected to the current path, preferably directly or indirectly to the terminal. In particular, the thermoelectric element is arranged inside the housing of the battery, i.e. not attached to the outside of the housing, but integrated into the battery. Furthermore, the thermoelectric element is attached in particular directly to the current path. This means in particular that the thermoelectric element is in direct contact with a conductor of the current path, preferably without insulation lying in between, but possibly also with such. The thermoelectric element is expediently attached to the current path by means of a thermally conductive adhesive, which is also still regarded as “attached directly to the current path”. As an alternative to fastening with an adhesive, a clamp, plug-in or screw fastening is also suitable. A heat-conducting paste is then expediently arranged between the current path and the thermoelectric element, this is also considered to be “attached directly to the current path”. The term “the thermoelectric element is attached directly to part A” is also generally understood to mean that the thermoelectric element is in direct contact with part A and between the thermoelectric element and part A there is only a material that is as thermally conductive as possible, preferably adhesive , is arranged.

The thermoelectric element is suitably a Peltier element. The thermoelectric element is characterized in that it has a cold side and a hot side and by applying a current, heat is transferred from the cold side to the hot side, so that cooling takes place on the cold side and heating on the hot side. When the current direction is reversed, the hot side and the cold side are also swapped, so that each adjustment of the current direction controls whether cooling or heating takes place on a given side. Conversely, when the thermoelectric element is not actively supplied with electricity, the thermoelectric element generates a voltage depending on a temperature difference between the cold side and the hot side, so that power generation is possible. For this purpose, the cell is preferably connected to the thermoelectric element and then represents an electrical resistance, so that a current is also generated by the thermoelectric element and the cell is then charged. In the present case, at least one of these three functions (cooling, heating, energy production) is used, preferably several of these functions are used, depending on the operating state of the battery. The thermoelectric element is designed, for example, as a foil or as a wire and generally has two connections for supplying the thermoelectric element with electrical energy and/or for dissipating electrical energy that is generated with the thermoelectric element.

Due to the typically low efficiency of a thermoelectric element of, for example, only 1 to 2%, it may not make sense to use a thermoelectric element at every point within the battery. Since more effective solutions are conceivable, at least for cooling and heating, the thermoelectric element is expediently used in addition to another temperature control solution and/or specifically at a so-called hot spot inside the battery. Correspondingly, in a suitable embodiment, the current path has a hot spot at which the thermoelectric element is arranged. A hot spot is characterized in particular by the fact that the temperature at this point is significantly higher than at other points, in particular at least 5 K, preferably at least 10 K and particularly preferably at least 20 K higher than the average along the entire current path. A hot spot is generally an area with an above average temperature compared to the area surrounding the hot spot. A hot spot in a cell does not necessarily arise as a result of a high level of waste heat being generated, but rather because there is only a small thermal mass in the relevant area in order to absorb the waste heat produced and thereby achieve a buffer effect. This is typically the case in current-carrying components away from the cell stack, while more heat is generated in the cell stack itself, but due to the typically large thermal mass, it can also be stored there without leading to a significant increase in temperature. Accordingly, there is a high thermal gradient at the hot spot. A hot spot is, for example, a point at which a conductor cross section of the current path is reduced, or a point at which two different conductors meet and are connected to one another, for example welded or screwed.

A configuration in which the thermoelectric element is fitted inside the cell housing at the terminal of the cell is particularly advantageous. The thermoelectric element is therefore not only arranged inside the battery, but even inside the cell, so that temperature control (cooling and/or heating) and/or energy generation is realized at the cell level and not just at the module level. In principle, it is already advantageous to arrange the thermoelectric element generally within the cell. However, the arrangement at the terminal described here is particularly advantageous since the terminal regularly generates a particularly large amount of waste heat during operation and is also regularly a hot spot, in particular because the entire current of the cell passes through the terminal.

The terminal (all versions can advantageously also be applied to the other terminal) generally has, in particular, an external contact which is completely outside the cell housing or is formed on the outside of the cell housing, an internal contact which is completely inside the cell housing or is formed on the inside of the cell housing, and a connection part which passes through the cell case or is a part of the cell case and which electrically connects the inner contact to the outer contact. The external contact is used to electrically connect the cell to other cells and/or to the battery poles. The inner contact serves in particular for the electrical connection to a cell stack of the cell within the cell housing. In particular, the cell stack has an active area and a plurality of electrode layers, each of which has an electrode tab that protrudes from the active area, and all of the electrode tabs are connected to one another and jointly connected to the inner contact. The inner contact is therefore also referred to as an arrester. For example, the electrode lugs are compacted together and welded to the inner contact. The further details of the cell stack are not relevant here. The connecting part is a bolt, for example, which passes through a suitable and, in particular, sealed opening in the cell housing. Preferably, the outer contact, the connecting part and the inner contact are three separate parts which are suitably connected to one another. However, an embodiment in which two or all three of these parts are manufactured in one piece, i.e. monolithically, is also conceivable and also suitable. The exact design of the terminal depends in particular on the cell type, i.e. the design of the cell. Examples of different cell types are a pouch cell, a prismatic cell or a round cell.

In a preferred embodiment, the thermoelectric element is attached directly to the inner contact. A particularly large amount of heat is regularly generated there when the battery is in operation. Attachment of the thermoelectric element directly to the inner contact and next to a contact area in which the electrode lugs are attached to the inner contact is particularly preferred.

As an alternative to the attachment mentioned within the cell housing, the thermoelectric element is attached in a suitable configuration outside the cell housing at one of the two terminals. The thermoelectric element is then attached in particular to the external contact or to an external side on the connecting part. A lot of heat is also regularly generated at these points. Both configurations (i.e. inside and outside the cell housing) can also be combined so that there are then two or more thermoelectric elements, at least one inside and at least one outside the cell, either at the same terminal or at different terminals or both.

In a further suitable embodiment, the battery has a number of cells and a bus bar (also referred to as a bus bar) which electrically connects the poles and the cells, more precisely their terminals, to one another. The busbar is generally outside the cell housing arranged and serves to combine the individual streams of the cells. The busbar is part of the current path and the thermoelectric element is then suitably attached to the busbar, preferably in close proximity to one of the two terminals of one of the cells. A strong heat development is also to be expected here.

The battery expediently has a control unit, to which the thermoelectric element is connected, for controlling the thermoelectric element. In one configuration, the control unit controls the power supply of the thermoelectric element. Alternatively or additionally, the control unit controls the generation of energy by means of the thermoelectric element. In any case, the control unit is connected to the thermoelectric element. For control, the control unit has one or more switches and/or a preferably adjustable resistor (or is connected to one or more such switches and/or such a resistor) for controlling the current and/or the voltage at the thermoelectric element. The control unit is either arranged inside the cell housing and then part of the corresponding cell or outside the cell housing, but expediently at least inside the battery housing. The arrangement within the cell has the advantages that an embodiment without additional lines and corresponding openings out of the cell is possible and that the control unit is arranged at cell level and does not have to be integrated into a superordinate module design. The arrangement outside the cell, on the other hand, has the advantage that a single control unit can be used to control a number of thermoelectric elements from different cells and is expediently also used.

The control unit is expediently fastened to the inside or outside of the cell housing by means of a thermally conductive adhesive. Such a thermally conductive connection of the control unit to the cell housing can also take place in other ways and is not absolutely necessary.

In addition to the temperature control (cooling and/or heating) and energy generation functions already mentioned, in an advantageous embodiment, a direct or indirect electrical connection of the thermoelectric element to the current path is used for voltage measurement. In a suitable configuration for this purpose, the control unit is designed to de-energize the thermoelectric element and then to measure a cell voltage of the cell. The control unit serves in particular as a voltage sensor. The voltage is measured in particular along a measurement path from one terminal to the other terminal. The control unit is then arranged along the measurement path. Depending on the configuration, the thermoelectric element is connected only thermally or both thermally and electrically to the current path, specifically to one of the terminals. The electrical connection serves in particular to supply the thermoelectric element with energy from the cell, as already described. The thermoelectric element for the electrical connection is preferably connected directly to the current path, in particular to one of the terminals (direct electrical connection), or only indirectly via the control unit (indirect electrical connection). In the case of an additional electrical connection as described, this then advantageously fulfills a dual function, namely serving on the one hand for electrical supply during operation of the thermoelectric element and on the other hand as a measuring path (or at least as part of a measuring path) for voltage measurement. For the voltage measurement it is sufficient if at least the control unit is connected to both terminals. For the voltage measurement, the thermoelectric element is then switched off in order not to falsify the result of the voltage measurement as an additional consumer. In the case of direct electrical connection of the thermoelectric element, this lies on the measurement path (this leads through the thermoelectric element, so to speak) and is therefore expediently switched off for voltage measurement. But even if the thermoelectric element is only electrically connected indirectly, i.e. if it is not on the measurement path, the thermoelectric element is expediently switched off for voltage measurement, since otherwise the current for operating the thermoelectric element flows at least partially via the measurement path and then falsifies the voltage measurement would.

In principle, two variants are suitable as the energy source for supplying the thermoelectric element for the purpose of cooling or heating the current path: firstly, the battery or the cell itself, secondly, an external energy source, in particular a vehicle electrical system. The thermoelectric element is suitably operated by means of recuperated braking energy from a vehicle in which the battery is installed. The recuperated braking energy is then supplied to the thermoelectric element in particular via the vehicle electrical system and expediently by means of the control unit. This prevents the battery itself from being discharged for temperature control. Supplying the thermoelectric element independently of the battery (or the individual cell) also has the advantage that a Tempe ration can be carried out independently of the current direction in the cell.

However, an embodiment in which the thermoelectric element--as already indicated above--is connected to the terminal of the cell for the power supply, in particular to both terminals, is just as advantageous. In this way, the cell then forms the energy source for supplying the thermoelectric element, so that the cell as a whole forms an integrated package in which the temperature control is independent of an external power supply.

Irrespective of whether the thermoelectric element is arranged inside or outside the cell, i.e. is thermally connected, the thermoelectric element is conveniently electrically connected to the two terminals either inside the cell or outside the cell, or both, i.e. at one of the two terminals outside the cell and at the other of the two terminals within the cell. The various configurations have various advantages. In order to achieve a particularly high level of integration with as few openings as possible in the cell housing, the thermoelectric element is expediently both itself arranged within the cell housing and connected to the two terminals. If the thermoelectric element is then also specifically attached directly to one of the terminals, the thermoelectric element is then connected both thermally and electrically to this terminal. The optional control unit is preferably also arranged within the cell housing, but this is not mandatory. In order to obtain as few breakthroughs as possible through the cell housing in a design with a thermoelectric element inside the cell housing and a control unit outside the cell housing (then e.g. also for controlling several thermoelectric elements), the thermoelectric element is electrically connected to one of the terminals inside the cell and other terminal outside the cell. With an arrangement of both the thermoelectric element and the control unit outside the cell housing, it is correspondingly advantageous if the thermoelectric element is connected to the two terminals outside the cell housing, then the thermoelectric element is connected both thermally and electrically to one of the terminals .

All of the named arrangements of the thermoelectric element relative to the cell and optionally in combination with a control unit inside or outside the cell are basically suitable both for temperature control and for energy production. Under certain circumstances, only the orientation of the cold and hot side of the thermoelectric element must be selected according to the desired function and/or the current direction through the thermoelectric element must be selected appropriately, e.g. using the control unit, or set by suitable wiring. Depending on the configuration, a respective function (cooling, heating, energy generation) is implemented either when charging and/or discharging the battery (or the individual cell).

In the method for operating a battery as described above, the current path is temperature-controlled using the thermoelectric element or energy is generated using the thermoelectric element, or both.

• 1 eine Batterie,
• 2 eine Zelle der Batterie aus 1,
• 3 eine Variante für die Zelle,
• 4 eine weitere Variante für die Zelle,
• 5 eine weitere Variante für die Zelle,
• 6 ausschnittsweise eine weitere Variante für die Zelle,
• 7 eine Energiegewinnung mit einem thermoelektrischem Element,
• 8 ein Ersatzschaltbild.

Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. They each show schematically:

• 1 a battery,
• 2 one cell of the battery 1 ,
• 3 a variant for the cell,
• 4 another variant for the cell,
• 5 another variant for the cell,
• 6 a detail of another variant for the cell,
• 7 an energy generation with a thermoelectric element,
• 8th an equivalent circuit.

1 shows a battery 2, for example a Li-ion battery. The battery 2 has two poles 4 for electrical connection, which protrude from a housing 6 of the battery 2 and represent an electrical connection of the battery 2 . The battery 2 also has at least one cell 8, here even a plurality of cells 8. Each cell 8 has a cell housing 10 and two terminals 12 for the electrical connection of the cell 8. In the present case, only cells 8 with two terminals 12 each are shown as an example , which protrude through the respective cell housing 10. However, the statements made here also apply analogously to cells 8 with a different number of terminals 12 and also to cells 8 in which one or more of the terminals 12 are not designed separately from the cell housing 10 as shown here, but are part of it.

The battery 2 also has a current path 14 which leads from within the cell 8 via one of the two terminals 12 to one of the two poles 4 . In the exemplary embodiment shown, the current path 14 consists of a plurality of conductors, including the pole 4 and the terminal 12, a conductor ter, here a busbar 16, for connecting the pole 4 and the terminal 6, this busbar 16 also connecting the terminals 12 of several cells 8.

The battery 2 further has a thermoelectric element 18, which is attached to the current path 14 (i.e. thermally connected) for heat exchange of the current path 14 with the thermoelectric element 18. The thermoelectric element 18 is integrated into the battery 2 and directly on the current path 14 attached, for example glued to the current path 14 with a thermally conductive adhesive.

The thermoelectric element 18 is, for example, a Peltier element and is characterized in that it has a cold side and a hot side and by applying a current heat is transferred from the cold side to the hot side, so that cooling takes place on the cold side and cooling on the hot side heating. When the current direction is reversed, the hot side and the cold side are also swapped, so that each adjustment of the current direction controls whether cooling or heating takes place on a given side. Conversely, when the thermoelectric element 18 is not actively supplied with current, the thermoelectric element 18 generates a voltage depending on a temperature difference between the cold side and the hot side, so that energy generation is possible. For this purpose, for example, the cell 8 is connected to the thermoelectric element 18 and then represents an electrical resistance, so that a current is also generated by the thermoelectric element 18 and the cell 8 is then charged.

In the present case, the current path 14 has a hot spot on which the thermoelectric element 18 is arranged. A hot spot is characterized by the fact that the temperature at this point is significantly higher than at other points in the company. In the 2 until 5 different exemplary embodiments are shown in which the terminals 12 in particular are hot spots and in which the thermoelectric element 18 is attached either directly to the terminal 12 or at least to the current path 14 in the spatial vicinity of the terminal 12 . The show 2 until 5 only a single cell 8 of the battery 2 in a sectional view.

In the 2 - 4 For example, the thermoelectric element 18 is attached to one of the two terminals 12 of the cell 8 within the cell housing 10 . In 5 Alternatively, the thermoelectric element 18 is attached to one of the two terminals 12 outside the cell housing 10 . The configurations shown can also be combined with one another.

In 6 a part of the cell 8 is shown in detail by way of example, from which the composition of the terminal 12 can also be seen. The terminal 12 has an outer contact 20, which lies completely outside the cell housing 10, an inner contact 22, which lies completely inside the cell housing 10, and a connecting part 24, which leads through the cell housing 10 and which electrically connects the inner contact 22 to the outer contact 20 connects. The outer contact 20 is used to electrically connect the cell 8 to other cells 8 and/or to the poles 4 of the battery 2, e.g. by means of the busbar 16. The inner contact 22 is used to electrically connect to a cell stack 26 within the cell housing 10. The cell stack 26 has an active area 28 and a plurality of electrode layers 30, each of which has an electrode tab 32 which protrudes from the active area 28, and all of the electrode tabs 32 are connected to one another and connected to the inner contact 22 in common. The connecting part 24 is a bolt here, which passes through a suitable and sealed opening in the cell housing 10 . However, the exact configuration of the terminal 12 is regularly dependent on the cell type, ie on the design of the cell 8, ie whether it is a pouch cell, a prismatic cell or a round cell, for example.

In 6 the thermoelectric element 18 is attached directly to the inner contact 22, more precisely even next to a contact area 34 in which the electrode lugs 32 are attached to the inner contact 22. In 6 If the cell housing 10 is not shown explicitly, it runs between the outer contact 20 and the inner contact 22.

In 1 the thermoelectric element 18 is attached to the busbar 16, more precisely even in spatial proximity to one of the two terminals 12 of one of the cells 8. In this case, in 1 For the sake of clarity, only a single thermoelectric element 18 is explicitly shown, but further thermoelectric elements 18 can be attached to the two busbars 16 analogously near the other terminals 12 and optionally also within the cells 8 as in FIGS 2 - 6 shown.

In the exemplary embodiments shown here, the battery 2 has a control unit 36 to which the thermoelectric element 18 is connected for control purposes. The control unit controls, for example, the power supply of the thermoelectric element 18 and/or the generation of energy by means of the thermoelectric element 18. In any case, the control unit 36 is connected to the thermoelectric element 18. As can be seen from the figures, there is also this more options. In this case, the arrangement of the control unit 36 is fundamentally independent of the arrangement of the thermoelectric element 18, so that the exemplary embodiments explicitly shown here are not an exhaustive list of all possible combinations. For control, the control unit 36 has one or more switches and/or a preferably adjustable resistor or is connected to such, for controlling the current and/or the voltage at the thermoelectric element 18. In 5 two switches 38 are shown by way of example, but can also be integrated into the control unit 36; one or more such switches 38 can also be added in the other exemplary embodiments.

The control unit 36 is either arranged within the cell housing 10 ( 2 ) and then part of the corresponding cell 8 or outside the cell case 10 ( 3 - 5 ). In 2 the control unit 36 is also attached to the inside of the cell housing 10, in the present case even thermally conductive by means of a thermally conductive adhesive 40, which is optional per se. Such a thermally conductive adhesive 40 is also used here to attach the thermoelectric element 18 to the terminal 12 or the busbar 16 .

Apart from the temperature control (cooling and/or heating) and energy generation functions already mentioned, in one embodiment a direct or indirect electrical connection of the thermoelectric element 18 to the current path 14 is used for a voltage measurement. For this purpose, the control unit 36 is designed, for example, to de-energize the thermoelectric element 18 and then to measure a cell voltage of the cell 8 . The voltage is measured along a measurement path from one terminal 12 to the other terminal 12, with the control unit 36 being arranged along the measurement path. Depending on the configuration, the thermoelectric element 18 is connected only thermally or both thermally and electrically to the current path 14, specifically to one of the terminals 12. For electrical connection, the thermoelectric element 18 is connected directly to the current path 14, e.g. to one of the terminals 12 (direct electrical connection, as in 4 and 5 shown) or only indirectly via the control unit 36 (indirect electrical connection, as in 2 shown). The electrical connection then fulfills a dual function, namely serving on the one hand for the electrical supply during operation of the thermoelectric element 18 and on the other hand as a measurement path (or at least as part of a measurement path) for voltage measurement. It is sufficient for the voltage measurement if at least the control unit 36 is connected to both terminals 12, e.g. as in 2 (but also in 4 and 5 ). For the voltage measurement, the thermoelectric element 18 is then switched off in order not to falsify the result of the voltage measurement as an additional consumer. In the case of direct electrical connection of the thermoelectric element ( 4 and 5 ) this is on the measuring path and is therefore switched off for voltage measurement. But even with only an indirect electrical connection of the thermoelectric element 18 ( 2 ), so if this is not on the measurement path, the thermoelectric element 18 is switched off for voltage measurement, since otherwise the current for operating the thermoelectric element 18 flows at least partially via the measurement path and would then falsify the voltage measurement.

In principle, two variants are suitable as the energy source for supplying the thermoelectric element 18 for the purpose of cooling or heating the current path 14: firstly, the battery 2 or the cell 8 itself (in 2 indirectly via the control unit 36 in which 4 and 5 immediately), secondly, an external source of energy, e.g. as in 3 a vehicle electrical system. In one possible configuration, the thermoelectric element 18 is operated by means of recuperated braking energy, which is supplied to the thermoelectric element 18 via the vehicle electrical system and by means of the control unit 36 . This prevents the battery 2 itself from being discharged for temperature control. The type of design of the energy source is also fundamentally independent of the arrangement of the thermoelectric element 18 and the control unit 36.

In the 2 , 4 and 5 the thermoelectric element 18 is connected to the two terminals 12 of the cell 8 for power supply, so that the cell itself forms the energy source for supplying the thermoelectric element 18 .

Regardless of whether the thermoelectric element 18 is arranged inside or outside the cell 8, the thermoelectric element 18 is either inside the cell 8 ( 2 ) or outside cell 8 ( 3 , 5 ) electrically connected to the two terminals 12 or both ( 4 ), ie at one of the two terminals 12 outside cell 8 and at the other of the two terminals 12 inside cell 8. In 2 the control unit 36 is also arranged within the cell housing 10, but this is not mandatory, as in FIGS 3 - 5 is recognizable.

All of the above arrangements of the thermoelectric element 18 relative to the cell 8 and optionally in combination with a control unit 36 inside or outside of the cell 8 are basically both for temperature control and for suitable for energy production. Under certain circumstances, only the orientation of the cold and hot side of the thermoelectric element 18 must be selected depending on the desired function and/or the current direction through the thermoelectric element 18 must be selected appropriately, e.g. by means of the control unit 36, or set by suitable wiring . Depending on the configuration, a respective function (cooling, heating, energy generation) is implemented either when charging and/or discharging the battery (or the individual cell).

For example shows 7 starting from 4 a use of the thermoelectric element 18 to generate energy when charging the cell 8, an electric drive 42 also being shown, which is not part of the battery 2 but is connected to it via a vehicle electrical system that is not explicitly shown. Alternatively, the thermoelectric element 18 can also be thermally and electrically connected to the other terminal 12 . 8th shows an equivalent circuit diagram of the situation 7 , but with three cells 8 instead of just one cell 8 and with a single control unit 36 controlling three thermoelectric elements 18 for each one of the cells 8. Therein, the cells 8, the thermoelectric elements 18 and the control unit 36 each represent a corresponding electrical resistance 7 and 8th arrows indicate the direction of the current. When discharging, the current direction is correspondingly reversed and it is then not possible to use the thermoelectric element 18 to generate energy.

Reference List

2

battery

4

pole

6

Housing

8th

cell

10

cell case

12

terminal

14

current path

16

busbar

18

thermoelectric element

20

external contact

22

internal contact

24

connection part

26

cell stack

28

active area

30

electrode location

32

electrode flag

34

contact area

36

control unit

38

Switch

40

thermally conductive adhesive

42

electric drive

Claims (10)

battery (2), - which has two poles (4) for electrical connection, - which has at least one cell (8), which has a cell housing (10) and at least one terminal (12), - which has a current path (14) which leads from within the cell (8) via the terminal (12) to one of the two poles (4), - Having a thermoelectric element (18) which is attached to the current path (14). battery (2) after claim 1 , The current path (14) having a hot-spot on which the thermoelectric element (18) is arranged. Battery (2) after one of Claims 1 or 2 wherein the thermoelectric element (18) is attached to the terminal (12) within the cell housing (10). battery (2) after claim 3 , wherein the terminal (12) has an outer contact (20) which is completely outside the cell housing (10), the terminal (12) having an inner contact (22) which is completely inside the cell housing (10), the terminal (12) has a connecting part (24) which leads through the cell housing (10) and which connects the inner contact (22) to the outer contact (20), the thermoelectric element (18) being attached directly to the inner contact (22). battery (2) after claim 1 or 2 wherein the thermoelectric element (18) outside the cell housing (10) is attached to the terminal (12). battery (2) after claim 1 or 2 , having a plurality of cells (8) and a busbar (16) electrically connecting the poles (4) and the cells (8) to one another, the busbar (16) being part of the current path (14) and the thermoelectric element (18) is attached to the busbar (16). Battery (2) after one of Claims 1 until 6 , This having a control unit (36) to which the thermoelectric element (18) is connected, for controlling the thermoelectric element (18). battery (2) after claim 7 , wherein the control unit (36) is designed to switch the thermoelectric element (18) to zero current and then to measure a cell voltage of the cell (8). Battery (2) after one of Claims 1 until 8th wherein the thermoelectric element (18) is connected to the terminal (12) of the cell (8) for power supply. Method for operating a battery (2) according to one of Claims 1 until 9 , wherein the current path (14) is temperature-controlled by means of the thermoelectric element (18) or wherein the thermoelectric element (18) generates energy or both.

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