BATTERY CELL FOR AN ELECTRICAL ENERGY STORAGE AND ELECTRICAL ENERGY STORAGE

Description

[0001] The invention relates to a battery cell for an electrical energy storage device, comprising electrochemically active components that comprise respective electrodes of the battery cell. Depending on the cell type, this may include a separator arranged between the electrodes and conductors that contact the respective electrodes. The conductors provide electrical connections for the battery cell. A casing device of the battery cell forms at least a partial region of an outer side of the battery cell. Furthermore, the invention relates to an electrical energy storage device comprising a plurality of such battery cells.

[0002] DE 10 2018 004 332 B3 describes a battery cell for a traction battery of a vehicle. The battery cell has a surface enlargement formed on an outer shell and on the electrodes, which is formed by a plurality of individual heat transfer elements, each thermally conductively connected to the outer shell and the electrodes.

[0003] WO 2015 / 065975 A1 describes a lithium-ion battery cell designed as a pouch cell. The pouch cell has a shell made of an electrically non-conductive, polymeric material. A negative electrical conductor and a positive electrical conductor of the pouch cell are coupled to respective electrodes in the form of an anode and a cathode, which are arranged within the electrically insulating shell. The negative electrical conductor and the positive electrical conductor are led out of the shell. The entire pouch cell is in turn arranged in a thermal shell formed from a carbon-based thermal film. Tabs of the thermal shell contact respective thermal management devices, which are designed to absorb and dissipate heat released by the pouch cell.

[0004] Both providing such a thermal envelope and arranging the pouch cell within the thermal envelope involve a relatively large amount of effort. This is disadvantageous.

[0005] Furthermore, it is possible to cool battery cells such as lithium-ion cells using cooling liquids or cooling plates that are attached to the outside of the battery cells. Compared to cooling lithium-ion cells using liquids or cooling plates, a cooling system based on air cooling is more cost-effective but less efficient. The main reason for this is that air has a lower heat capacity than common cooling liquids such as cooling water. Therefore, it is more difficult to dissipate the heat generated during operation of a lithium-ion cell using air cooling, for example when the battery cell is being charged, especially quickly, or when the battery cell is delivering very high power and is being discharged in the process.

[0006] In an air cooling system, air can be directed or circulated through spaces in the form of channels or gaps formed between individual battery cells or battery cells combined into cell packs. Air used as a coolant can be at room temperature or ambient temperature at the inlet of such an air cooling system. Furthermore, it is possible to supply an electrical energy storage device, such as a battery with a plurality of battery cells, with pre-cooled air for cooling purposes. As an alternative to an air cooling system, a cooling system with a liquid cooling fluid can also be used.

[0007] To heat the battery cells of an electrical energy storage device, it can be provided that electrically operated heating plates or heating mats are arranged between the battery cells or cell packs. Furthermore, a warm temperature control fluid can also be used to increase the temperature of the battery cells of an electrical energy storage device to a desired operating temperature, i.e., to heat the battery cells.

[0008] However, as mentioned above, it is comparatively difficult, particularly when an air cooling system is provided, to dissipate heat sufficiently from a battery cell during charging or discharging.

[0009] The object of the present invention is therefore to provide a battery cell of the type mentioned at the outset which is particularly easy to cool and to provide an electrical energy storage device with a plurality of such battery cells.

[0010] This object is achieved by a battery cell having the features of patent claim 1 and by an electrical energy storage device having the features of patent claim 7. Advantageous embodiments with expedient further developments of the invention are specified in the dependent patent claims.

[0011] The battery cell according to the invention for an electrical energy storage device has electrochemically active components which comprise respective electrodes of the battery cell. A separator of the battery cell is arranged between the electrodes. Furthermore, the battery cell has conductors which contact the respective electrodes and through which electrical connections of the battery cell are provided. A casing device of the battery cell forms at least a partial region of an outer side of the battery cell. The casing device has a plurality of structural elements by means of which a surface of the casing device is enlarged compared to a casing device without the structural elements. In other words, the structural elements ensure that the outer surface of the casing device is larger than would be the case with a casing device of the same dimensions which did not have the structural elements.

[0012] The battery cell is designed as a pouch cell, with the enveloping device comprising the pouch film formed from the electrically insulating material, which encloses the electrochemically active components of the battery cell. In this way, the pouch film, which is already provided to provide the pouch cell and serves as a protective cover, can be given additional functionality by providing the enveloping device, which has the structural elements, through the pouch film.

[0013] A portion of at least one of the structural elements extends through the pouch film of the battery cell, which encloses the electrochemically active components of the battery cell. The portion extending into the interior of the battery cell is particularly effective at dissipating heat from the interior of the battery cell to the outside or introducing it into the interior of the battery cell.

[0014] The section of the at least one structural element that passes through the pouch film thermally contacts at least one of the conductors of the battery cell, providing electrical insulation. Since the conductors of battery cells designed as lithium-ion cells are typically made of aluminum for the positive electrode and copper for the negative electrode, thermal contact of such highly thermally conductive conductors with the sections of the structural elements results in particularly good heat conduction from the battery cell to the environment or from the environment to the battery cell.

[0015] Due to the increased surface area of ​​the battery cell provided by the casing, the battery cell is particularly easy to cool or heat. This applies, for example, when the battery cell is exposed to a liquid cooling medium, but especially when air is used as the cooling medium or generally as a temperature control fluid. This is because the air flowing around the structural elements of the casing can dissipate heat from the battery cell particularly well via these numerous structural elements. This enables particularly effective heat dissipation from the battery cell. This makes it possible to provide a very efficient cooling system. This, in turn, has a positive impact on the performance and efficiency of the battery cell and on the service life of the battery cell, which can in particular be a lithium-ion cell.

[0016] Furthermore, the battery cell can also be heated very easily and quickly, for example, when this is necessary in cold ambient temperatures to quickly bring the battery cell to a predetermined operating temperature. Furthermore, such preheating may be necessary if the battery cell is to be charged, especially quickly. Due to the very large outer surface of the battery cell provided by the structural elements, the battery cell can also be heated very effectively by applying a hot or warm temperature control fluid, in particular hot air or cooling liquid.

[0017] The structural elements other than the electrical connections of the battery cell thus lead to an increase in the effective surface area of ​​the battery cell or of a cell pack or cell stack comprising a plurality of battery cells packed together. Furthermore, improved thermal coupling with a circulating temperature control fluid, in particular with circulating air, for heating or cooling is achievable.

[0018] This makes it possible to achieve both improved cooling and improved heating of the battery cell, while maintaining the same cooling or heating performance of an available temperature control system or thermal management system.

[0019] Furthermore, compared to a battery cell with a casing device without the structural elements, the battery cell can be manufactured with only one additional manufacturing step, or even the same number of manufacturing steps. This makes the battery cell particularly low-cost to manufacture.

[0020] In addition, cost-effective materials can be used to provide the structural elements, so that the battery cell with improved temperature controllability can be provided particularly cost-effectively.

[0021] The enveloping device preferably comprises a base body formed from a flexible and / or elastic material and the structural elements, wherein the structural elements protrude beyond the base body in some areas. Due to the flexibility and / or elasticity of the base body, the enveloping device can adapt to a change in volume of a region of the battery cell enclosed by the enveloping device. The properties of the base body serving as the carrier material for the structural elements can thus vary, in particular intelligently, with a changing temperature of the battery cell. For example, if the volume of the battery cell increases, as can occur as a result of charging the battery cell, the heat released during charging can be very effectively dissipated via the structural elements, which protrude beyond the base body in some areas.

[0022] Furthermore, the protrusion of structural elements beyond the base body ensures that turbulence is introduced into the temperature control fluid flowing over the structural elements, particularly into the air or cooling fluid flowing over the structural elements. A turbulent flow of the temperature control fluid, especially the air, leads to particularly efficient convective heat removal from the battery cell when the battery cell needs to be cooled. Furthermore, a temperature control fluid with a turbulent flow can also result in very efficient heating of the battery cell.

[0023] Preferably, the structural elements are made of a material with a higher thermal conductivity than the material of the base body. This allows heat to be dissipated particularly effectively from the battery cell or introduced into the battery cell via the structural elements.

[0024] In particular, the structural elements can be formed from at least one metal, which also includes a metallic alloy. The structural elements can be provided particularly cost-effectively if they are made of aluminum or an aluminum alloy. Although the use of copper is less cost-effective, copper exhibits very high thermal conductivity. Therefore, copper or a copper-containing alloy is also suitable for providing the structural elements.

[0025] The structural elements can be designed, in particular, as hairs and / or flakes and / or lamellae. The thickness of the structural elements can range from micrometers to millimeters, and the length of the structural elements can range from millimeters to centimeters. Such structural elements, designed, for example, like cooling fibers or cooling fins, directly on the outside of the battery cell ensure a particularly large surface area over which the temperature control fluid can flow.

[0026] When using at least one metal, which should always be understood as a metallic alloy, to provide the structural elements and a plastic material to provide a base body, the enveloping device can accordingly be formed from a composite material comprising the plastic and the at least one metal. In particular, the at least one metal can be applied in the form of a foil to a foil-like base body. The structural elements, which ensure the provision of the particularly large surface area of ​​the enveloping device, can be formed from the metallic foil. Thus, a functional foil is provided as an enveloping device for the battery cell in a cost-effective manner.

[0027] The at least one metal forming the structural elements, which preferably has a higher thermal conductivity than the material of the base body, can, in particular, have properties that vary depending on temperature. For example, the metal can have a memory effect, due to which the shape assumed by the metallic structural element varies depending on temperature. Such intelligent composite materials are advantageous for providing the casing device.

[0028] Preferably, a portion of at least one of the structural elements rests against the pouch film of the battery cell, which is formed from an electrically insulating material and encloses the electrochemically active components of the battery cell. In this way, heat can be particularly effectively dissipated from the interior of the battery cell via the portion resting against the pouch film or introduced into the interior of the battery cell.

[0029] Preferably, a size of the section and / or a length of an end region of at least one of the structural elements projecting beyond the base body can be varied depending on the volume of a region of the battery cell enclosed by the pouch film. In particular, a larger section can abut the pouch film if the volume of the region of the battery cell enclosed by the pouch film increases. Furthermore, an end region of greater length can project beyond the base body if the volume of the region of the battery cell enclosed by the pouch film increases.

[0030] In this way, it is possible to take into account the fact that the thickness of battery cells designed as lithium-ion cells can change depending on the aging of the battery cell and / or depending on the state of charge of the battery cell. For example, due to cell aging, the thickness of the battery cell can increase, whereby the volume of the area of ​​the battery cell enclosed by the pouch film increases. In an electrical energy storage device which has adjacently arranged battery cells, the case can then arise that the spaces between the adjacent battery cells serving as channels for a temperature control fluid become narrower. Nevertheless, even in this case, heat can be effectively dissipated from the battery cells or introduced into the battery cells via the structural elements.This can be facilitated if the thermal contact area with the pouch film, which encloses the electrochemically active components of the battery cell, increases with increasing battery cell thickness. This is because the dynamically changing thermal contact area, which increases, for example, due to the increase in thickness, allows for improved heat dissipation from the battery cell or heat transfer into the battery cell. Thus, the heat dissipation achievable via the envelope device increases as the battery cell becomes thicker over the course of its aging.

[0031] Furthermore, it is beneficial for dissipating heat from the battery cell and introducing heat into the battery cell if the length of the end region of at least one of the structural elements projecting beyond the base body increases with an increase in the volume of the area of ​​the battery cell enclosed by the pouch film. This is because the temperature control fluid can then flow around a particularly long end region of the at least one structural element.

[0032] In particular, the structural elements can be introduced into the casing device of the pouch cell comprising a metallic layer, for example by processing the metal foil with a laser or by welding processes or the like.

[0033] The advantage here is that the enveloping device does not need to be formed as an additional sheath around the battery cell. Rather, the enveloping device, which has the plurality of structural elements, can be provided simultaneously during the manufacture of the pouch cell and the insertion or attachment of the protective sheath that is already provided and surrounds the electrochemically active components of the pouch cell. The insertion of the enveloping device into the battery cell can thus be carried out particularly during the manufacture of the battery cell. This makes the production of the easily temperature-controlled battery cell particularly low-cost.

[0034] The structural elements can have an electrically insulating coating, either partially or completely. Such a coating, preferably a very thin one, reduces the thermally conductive properties of structural elements made of metal only insignificantly. Nevertheless, this method can prevent the structural elements from establishing an electrically conductive connection between components of the battery cell or between battery cells, which should be avoided if possible.

[0035] The electrical energy storage device according to the invention comprises a plurality of battery cells according to the invention. This allows the electrical energy storage device, embodied, for example, as a high-voltage battery for a motor vehicle, to be particularly easily temperature-controlled, in particular cooled. This is especially true when a temperature-control fluid is used for direct cooling or heating. The high-voltage battery can provide a nominal voltage of more than 60 volts and, in particular, several hundred volts.

[0036] Preferably, a space through which a temperature control fluid can flow is formed between two adjacent battery cells of the electrical energy storage device, into which at least portions of the structural elements extend. In this way, heat can be particularly effectively introduced into the battery cells of the electrical energy storage device or heat can be dissipated from the battery cells when the fluid flows through the space.

[0037] Preferably, at least one of the structural elements of a first battery cell of two adjacent battery cells contacts a second battery cell of the two adjacent battery cells. In this way, the available space between the structural elements is particularly well utilized.

[0038] Additionally or alternatively, it can be provided that the regions of the structural elements of adjacent battery cells arranged in the gap keep the adjacent battery cells at a distance from one another as the size of the gap decreases. The structural elements thus serve not only to expand the surface area of ​​the battery cells but also ensure that the battery cells are spaced apart from one another and that the battery cells are pressed against one another when the gap between the adjacent battery cells becomes smaller, for example due to an increase in the thickness of the battery cells during charging and / or due to cell thickness growth as the battery cells age.

[0039] Because the structural elements keep the battery cells at a distance from each other, even in such cases, good heat dissipation from the battery cells or good heat introduction into the battery cells can be achieved by passing the temperature control fluid through the space between the adjacent battery cells.

[0040] The advantages and preferred embodiments described for the battery cell according to the invention also apply to the electrical energy storage device according to the invention and vice versa.

[0041] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.

[0042] Showing: Fig. 1 shows a schematic, end-side view of a battery cell with a covering device in the form of a surface extension film, which runs circumferentially around an active area of ​​the battery cell and completely encloses the active area in the circumferential direction; Fig. 2 shows a side view of the battery cell according to Fig. 1; Fig. 3 a top view of the battery cell according to Fig. 1 ; Fig. 4 in a schematic, frontal view of a variant of the battery cell in which the casing device only partially covers the active area; Fig. 5 a side view of the battery cell according to Fig. 4 , Fig. 6 a top view of the battery cell according to Fig. 4 ; Fig. 7 shows a schematic and partially sectioned view of a section of the uncharged or not yet aged battery cell, wherein structural elements of the surface extension film are shown schematically; Fig. 8 shows a view according to Fig. 7, wherein the battery cell is in a fully charged state or is severely aged and is close to the end of its service life; Fig. 9 shows a section of an electrical energy storage device comprising a plurality of battery cells, wherein the structural elements of the surface extension film protrude into spaces formed between the battery cells; Fig. 10 shows the state of the electrical energy storage device according to Fig. 9 at full charge or after an age-related thickness increase of the battery cells; Fig. 11 a variant of the electrical energy storage device according to Fig. 9 , in which, in contrast to the variant according to Fig. 9 two battery cells are combined to form a cell pack or cell package; and Fig. 12 the variant according to Fig. 11 , whereby the spaces between the battery cells are reduced due to an increase in the thickness of the battery cells.

[0043] In the figures, identical or functionally identical elements are provided with the same reference numerals.

[0044] In Fig. 1 A battery cell 10 is shown in a highly schematic manner, which can be designed in particular as a so-called pouch cell. An active region 12 of the battery cell 10, which with regard to its electrochemically active components can be designed in particular as a lithium-ion cell, is enclosed in the present case by a pouch film 14 formed from an electrically insulating material. From this pouch film 14, designed in the manner of a protective sheath, electrical connections of the battery cell 10 emerge in the form of a positive conductor 16 or positive pole of the battery cell 10 and a negative conductor 18 or negative pole of the battery cell 10 (cf. Fig. 2). Within the active region 12 enclosed by the pouch film 14 are the electrochemically active components of the battery cell 10, i.e., respective electrodes in the form of a cathode and an anode, wherein a separator can be arranged between these electrodes. The respective electrodes are contacted by conductors in a manner not shown in detail here, through which the electrical connections 16, 18 of the battery cell are provided. Furthermore, a liquid or solid electrolyte is present in the active region 12 of the battery cell 10.

[0045] Such battery cells 10 can be used in an electrical energy storage device 20, which is shown in detail and schematically in Fig. 9shown, be arranged at a distance from one another. Accordingly, gaps 22 are formed between the battery cells 10, through which gaps a liquid or gaseous temperature control fluid can be passed for cooling or heating, i.e. for temperature control of the battery cells 10. In particular, when air is used as the temperature control fluid, i.e. in an air-cooled or air-tempered electrical energy storage device 20, it proves difficult to ensure sufficient heat dissipation via the air for cooling the battery cells 10 and to quickly introduce heat into the battery cells by means of the air for heating the battery cells 10.

[0046] In the present case, however, the battery cells 10 can be cooled and heated very easily and effectively even when using air as the temperature control fluid. This is because the respective battery cell 10 has a casing device 24 (see Fig. 1) with a plurality of structural elements 26. The Fig. 1 Structural elements 26 not explicitly shown can be designed, for example, as hairs, as flakes, as lamellae or the like.

[0047] In the schematic representation of a section of the battery cell 10 in Fig. 7 The structural elements 26 of the enveloping device 24 are shown as fine hairs, with only some of the structural elements 26 being provided with a reference numeral. By providing such structural elements 26, a surface area of ​​the enveloping device 24 is significantly larger than would be the case if the enveloping device 24 did not have the structural elements 26. Accordingly, the enveloping device 24, which is designed in the manner of a film, serves as a surface extension film of the battery cell 10.

[0048] Due to the greatly enlarged outer surface of the battery cell 10, heat can be easily dissipated from the battery cells 10 using the air as a temperature control fluid, or heat can be introduced into the battery cells 10 when heating the battery cells 10. However, this also applies if a liquid temperature control fluid is used to control the temperature of the battery cell 10.

[0049] The incorporation of the structural elements 26 into those sides of a cell that are perpendicular to the main surface of the active layers of the cell is particularly advantageous, as the heat within the active layer is transported very effectively to the edge regions. In particular, the heat transport across different active layers is lower, so that the cooling effect on the main surface of the cells is less effective. Thus, the incorporation of the structural elements on or into the pouch film 14 of the Figures 4 and 5 areas shown are particularly effective.

[0050] Out of Fig. 2 and Fig. 3It can be seen that the structured or functional film, by which the enveloping device 24 is provided, can completely envelop the active region 12 of the battery cell 10 in the circumferential direction, so that narrow sides (cf. Fig. 2 ) and broadsides (compare Fig. 3 ) of the presently flat and substantially cuboid-shaped battery cell 10 are almost completely covered by the casing device 24. With the exception of free ends, in which the terminals 16, 18 emerge from the active area 12 enclosed by the electrically insulating pouch film 14, Fig. 1 to Fig. 3 In the variant of the battery cell 10 shown, an outer side of the battery cell 10 is formed by the casing device 24.

[0051] Such encasing of the active region 12 with the textured or functional film in the form of the enveloping device 24 is particularly easy to implement in terms of manufacturing technology. Furthermore, the comparatively large surface area of ​​the enveloping device 24 allows heat to be dissipated particularly effectively from the battery cell 10 or introduced into the battery cell 10.

[0052] As from Fig. 4 to Fig. 6 However, as can be seen, in the battery cell 10 the casing device 24 may not be formed completely around the active region 12.

[0053] Out of Fig. 4 to Fig. 6 It is particularly evident that in corner regions 28 of the battery cell 10, an outer side of the battery cell 10 may be formed not by the covering device 24, but by the pouch film 14 which is freely accessible in the corner regions 28. Accordingly, only on the narrow sides (cf. Fig. 5 and Fig. 6 ) as well as on a top side and a bottom side (compare Fig. 5 and Fig. 6) of the battery cell 10, through which the covering device 24 is provided. Here, these strips then form the outer side of the battery cell 10.

[0054] At the Fig. 4 to Fig. 6 In the variant shown, in which the strips of the surface extension film formed by the covering device 24 cover only parts of the active area 12, larger areas are available to which the battery cell 10 can be coupled to a frame (not shown here) of the electrical energy storage device 20 in order to adjust the distance between the battery cells 10 and thus ensure the formation of the spaces 22 between the battery cells 10 (cf. Fig. 9 ).

[0055] In particular from Fig. 7 and Fig. 8It can be seen that the film forming the sheathing device 24 can be formed simply and cost-effectively from a composite material. The sheathing device 24 comprises a base body 30, for example, made of plastic, with the structural elements 26 incorporated into the base body 30.

[0056] The structural elements 26 can be arranged according to the schematic representation in Fig. 7 For example, they can be formed as hairs made of at least one metal or a metallic compound. These hairs, which have a greater thermal conductivity than the base body 30, not only increase the effective surface area of ​​the battery cell 10. Therefore, not only can the heat generated during the discharging operation of the battery cells 10 or during the charging of the battery cells 10 be effectively transferred into the circulated air, which in Fig. 7This is illustrated by flow arrows 32. Rather, the structural elements 26 preferably also ensure a turbulent air flow. This leads to a particularly effective introduction of heat into the battery cell 10, analogous to the cooling of the battery cell 10 when heating the battery cell 10. Such heating of the battery cell 10 is advantageous, for example, in cold weather or when the battery cells 10 are to be preheated for charging, particularly rapid charging.

[0057] When the sheathing device 24 is made of the composite material, it is advantageous if the carrier material in the form of the base body 30 consists of a flexible or shrinkable plastic, while the mainly heat-conducting material of the sheathing device 24 in the form of the structural elements 26 is formed from at least one metal or a metal compound.

[0058] Furthermore, a respective section 34 of the structural elements 26 can rest against the pouch film 14 of the battery cell 10, which is formed from the electrically insulating material. Thus, heat from the active region 12 can be effectively absorbed via this section 34 and subsequently released into the cooling air or the cooling liquid. Free end regions 36 of the structural elements 26 projecting beyond the base body 30 ensure good contact with the cooling fluid and preferably also cause the turbulent flow of the cooling fluid. Heat release or heat absorption of the battery cell 10 via the casing device 24 and in particular its structural elements 26 is Fig. 7 and in Fig. 8 illustrated by a double arrow 38.

[0059] Fig. 7 shows the battery cell 10 in detail at the beginning of its service life, i.e. the battery cell 10 which is still largely unaged. Fig. 7In this regard, it is evident that the size of the section 34 that abuts the pouch film 14 is still comparatively small. In other words, the contact area of ​​the structural elements 26 or components with a higher thermal conductivity embedded in the base body 30 is limited within the elastic second outer skin of the battery cell 10, which is provided by the enveloping device 24.

[0060] In Fig. 8 In contrast, the state of the battery cell 10 is shown when it is approaching its end of life, i.e., when it has aged comparatively significantly. It can be seen that the base body 30 of the enveloping device 24 is stretched. This is due to the fact that the active area 12 enclosed by the pouch film 14 increases in thickness due to the aging of the battery cell 10. This also leads to the gaps 22 between the battery cells 10 becoming narrower (see Fig. 10 ).

[0061] Preferably, the structural elements 26 are arranged in the base body 30 such that, as the gaps 22 become narrower, the contact area of ​​the structural elements 26 with the pouch film 14 increases. Accordingly, the size of the section 34 in which the structural elements 26 abut the pouch film 14 increases. Furthermore, the enlarged contact area of ​​the structural elements simultaneously enables mutual compression of opposing, i.e., adjacently arranged cells.

[0062] Increasing the contact area between the structural elements 26 and the pouch film 14 and / or allowing the larger end region 36 to project beyond the base body 30 can be achieved, in particular, by appropriately shaping the structural elements 26 and embedding them in the base body 30. For example, the structural elements 26 can support each other and thus ensure the behavior described above.

[0063] Both the dynamically enlarged contact area of ​​the structural elements 26 with the pouch film 14 and the greater length of the exposed end regions 36 ensure improved heat dissipation from the battery cell 10 when cooling the battery cell 10. Accordingly, the thinning of the cooling channels, i.e. the gaps 22 (compare Fig. 10 ), can be compensated for to a particularly large extent. Thus, even with narrow gaps 22, good cooling of the battery cells 10 can be achieved. Furthermore, during heating, i.e., when heat is introduced into the battery cells 10, the heating power can be reduced as the thickness of the battery cells 10 increases.

[0064] In Fig. 9It is evident how several battery cells 10 can be arranged adjacent to one another in the electrical energy storage device 20. Between the adjacent battery cells 10, the respective intermediate spaces 22 are formed, through which the fluid flow in the form of cooling air or cooling liquid can flow. The fluid flow through the intermediate spaces 22 along the broad sides of the battery cells 10 is Fig. 9 illustrated by corresponding symbols 40.

[0065] Out of Fig. 9It is further evident that the structural elements 26 of the adjacent battery cells 10 are in contact with one another. The metal structures in the form of the structural elements 26 therefore not only serve to enlarge or expand an outer surface of the respective battery cells 10. Rather, the structural elements 26 can also ensure that the adjacent battery cells 10 are kept at a distance from one another. The structural elements 26 can furthermore be designed to be elastic and thus serve to press the battery cells 10 together in the electrical energy storage device 20. In this case, the structural elements are each arranged on a cell, in particular in a materially bonded manner with the pouch film, and protrude from it or are part of the pouch film. These structural elements, which are designed as part of the pouch film of a cell, mechanically support the respective cell relative to the cell adjacent to it.

[0066] In Fig. 10It is illustrated how, due to a growth in thickness of the battery cells 10, for example, due to the so-called cell respiration during charging and / or as a result of the aging of the battery cells 10, the gaps 22 between the adjacent battery cells 10 become narrower. Nevertheless, the structural elements 26 keep the adjacent battery cells 10 at a distance from each other and simultaneously press them against each other. Furthermore, the larger contact area of ​​the structural elements 26 with the pouch films 14 of the respective battery cells 10 provides a large heat transfer area. Also in the Fig. 10 In the situation shown, the structural elements 26 also serve to press the battery cells 10.

[0067] In Fig. 11 is a Fig. 9A corresponding situation is shown in a variant of the electrical energy storage device 20. However, here, two adjacent battery cells 10 are combined to form a cell stack 42 or cell pack. Accordingly, these battery cells 10 lie directly against one another on one side. On the opposite sides, however, the respective intermediate space 22 is formed between these battery cells 10 of the cell stack 42 and other adjacent battery cells 10. Here, too, the structural elements 26 extend into the respective intermediate spaces 22, which ensure the surface expansion, spacing, and compression of the battery cells 10 in the electrical energy storage device 20.

[0068] Out of Fig. 12It is evident that even in such an electrical energy storage device 20, the gaps 22 can become smaller as a result of an increase in the thickness of the battery cells 10. Nevertheless, the structural elements 26 ensure that the cell packs 42 are kept at a distance from one another. Furthermore, the deformed structural elements 26 preferably provide the enlarged heat transport surface, as described above with reference to Fig. 7 and Fig. 8 is explained.

[0069] During the manufacture of the battery cells 10, the insertion or attachment of the covering device 24 is preferably carried out as one of the last steps directly during the manufacture of the battery cell 10. Accordingly, in particular, a conventional protective film, such as that used as a protective cover in a battery cell 10 designed as a pouch cell, can be replaced by the textured or structured covering device 24 or film described here. List of reference symbols

[0070] 10Battery cell 12Active area 14Pouch film 16Arrester 18Arrester 20Energy storage 22Gap 24Envelope device 26Structural element 28Corner area 30Main body 32Flow arrow 34Section 36End area 38Double arrow 40Symbol 42Cell package

Claims

1. Battery cell for an electrical energy storage device (20), comprising electrochemically active components which comprise respective electrodes of the battery cell (10), comprising conductors contacting the respective electrodes, through which electrical connections (16, 18) of the battery cell (10) are provided, and comprising a casing device (24) which forms at least a partial region of an outer side of the battery cell (10), the casing device (24) having a plurality of structural elements (26) by means of which a surface of the casing device (24) is enlarged in comparison with a casing device without the structural elements, the battery cell (10) being designed as a pouch cell, and the casing device (24) comprising a pouch film (14) formed from an electrically insulating material, characterized in that a portion (34) of at least one of the structural elements (26) passes through the pouch film (14), the portion (34) of the at least one structural element (26) passing through the pouch film (14) thermally contacting at least one of the conductors of the battery cell (10) in an electrically insulating manner.

2. Battery cell according to claim 1, characterized in that the casing device (24) comprises a main body (30) formed from a flexible and / or elastic material, in particular a metal material or plastics material, and the structural elements (26), the structural elements (26) protruding beyond the main body (30) in some regions.

3. Battery cell according to claim 2, characterized in that the structural elements (26), in particular designed as tiny hairs and / or flakes and / or lamellae, are made of a material which has a thermal conductivity equal to or greater than that of the material of the main body (30), in particular are made of at least one metal.

4. Battery cell according to any of claims 1 to 3, characterized in that a portion (34) of at least one of the structural elements (26) rests on the pouch film (14) of the battery cell (10), which encloses the electrochemically active components of the battery cell (10).

5. Battery cell according to any of claims 1 to 4, characterized in that a size of the portion (34) and / or a length of an end region (36) of at least one of the structural elements (26) protruding beyond the main body (30) can be changed depending on a volume of a region (12) of the battery cell (10) enclosed by the pouch film (14).

6. Battery cell according to any of claims 1 to 5, characterized in that the structural elements (26) have an electrically insulating coating.

7. Electrical energy storage device with a plurality of battery cells (10) according to any of claims 1 to 6, wherein between two adjacent battery cells (10) a gap (22) is formed through which a temperature control fluid can flow, into which at least regions of the structural elements (26) extend.

8. Electrical energy storage device according to claim 7, characterized in that at least one of the structural elements (26) of a first battery cell (10) of two adjacent battery cells (10) contacts a second battery cell (10) of the two adjacent battery cells (10) and / or the regions of the structural elements (26) of adjacent battery cells (10) arranged in the gap (22) keep the adjacent battery cells (10) at a distance from one another when a size of the gap (22) is reduced and serves to press the battery cells together.