Cover assembly for a battery cell of an electrical energy store of an at least partially electrically operated motor vehicle, housing, and battery cell

Abstract

The invention relates to a cover assembly (36) for a battery cell (16) of an electrical energy store (12) of an at least partially electrically operated motor vehicle (10), having an outer side (38), which faces a cooling device (22) of the electrical energy store (12), and having an inner side (40), which is located opposite the outer side (38) and which faces a cell winding (20) of the battery cell (16), wherein at least one busbar (32) is formed on the inner side (16) and is designed to receive electrical energy from the cell winding (20), the busbar (32) being cooled via the cooling device (22). The invention also relates to a housing (18) and to a battery cell (16).

Description

[0001] Mercedes-Benz Group AG

[0002] Cover assembly for a battery cell of an electrical energy storage device of an at least partially electrically powered motor vehicle, housing, and battery cell

[0003] The following invention relates to a cover assembly for a battery cell of an electrical energy storage device of an at least partially electrically powered motor vehicle according to the applicable claim 1. The invention further relates to a corresponding housing with a cover assembly, and a battery cell.

[0004] It is already known from the prior art that a current winding in a housing has corresponding current busbars, which then form a positive and a negative terminal for the entire battery cell. The problem with cooling the current busbars of the cell winding of battery cells lies particularly in the fact that they are attached directly to the cells and connect individual battery cells or groups of battery cells to each other. This type of current busbar is usually even more closely integrated with the battery cell and may therefore offer correspondingly limited space for cooling measures.Thus, the challenges for cooling such a busbar are limited space and the integration of the cooling system, the contact resistance between the busbars and battery cells, which leads to an increase in Joule heat and thus can lead to greater heating of the busbars, as well as the difficulty in integrating cooling systems into the cell winding, especially if active cooling methods such as liquid cooling are to be used.

[0005] Therefore, the thermal management of current busbars for cell windings requires careful planning and optimization to achieve the best performance while ensuring integration into the overall system. DE 10 2011 109 203 A relates to a single cell for a battery cell, comprising a stack of electrode foils arranged in a housing formed from two cladding sheets and a frame by means of which the two cladding sheets are electrically insulated from each other, wherein current conductor tabs of electrode foils of one polarity are connected to each other to form a pole contact, and the respective pole contact is connected to a cladding sheet, and each cladding sheet forms one electrical pole of the single cell.It is provided that the current collector tabs of the same polarity are led out on each pole side of the electrode foil stack and are connected to each other in a central area of ​​the pole side to form the pole contact, wherein the pole contacts are angled parallel to the pole side, in particular to one half of the respective pole side, and are connected to a covering plate.

[0006] DE 10 2008 059 963 A1 relates to a single cell for a battery and a method for its manufacture. The single cell comprises an electrode stack arranged within a cell housing, the individual electrodes of which, preferably electrode foils, are electrically connected to current collector tabs, wherein at least electrodes of different polarities are insulated from one another by a separator, preferably a separator foil, wherein current collector tabs of the same polarity are electrically connected to one another to form a pole, wherein the current collector tabs of one pole are electrically pressed and / or welded together, wherein the cell housing comprises two electrically conductive housing parts which are electrically insulated from one another, wherein the current collector tabs of each polarity are electrically connected to one of the electrically conductive housing parts.The current collector tabs of each polarity are electrically connected to the electrically conductive housing part by indirect spot welding using two welding electrodes pressed onto the housing part.

[0007] DE 102015 010426 Al relates to a single cell for an electric battery with a flat electrode arrangement and a cell housing formed from at least two foil sections, wherein the electrode arrangement is located inside the cell housing, electrical poles of the electrode arrangement are connected to current collectors, and the current collectors are electrically insulated and fluid-tight in a region between the two foil sections, with the two foil sections being connected to each other and to the current collectors by means of a sealing seam circumferentially around the edge of the electrode arrangement. It is provided that at least one electrical pole of the electrode arrangement and / or at least one current collector connected to this pole is angled inside the cell housing such that a current collector angle of between 60 degrees and 120 degrees is enclosed between a flat side of the current collector and a flat side of the electrode arrangement.Furthermore, the sealing seam runs in at least two planes, with a sealing seam angle in the range of 60 degrees to 120 degrees being included between at least one plane of the sealing seam and a flat side of the electrode arrangement.

[0008] The object of the present invention is to create a lid assembly, a housing and a battery cell by means of which improved cooling of the battery cell can be achieved.

[0009] This problem is solved by a cover assembly, a housing, and a battery cell according to the independent claims. Advantageous embodiments are specified in the dependent claims.

[0010] One aspect of the invention relates to a cover assembly for a battery cell of an electrical energy storage device of an at least partially electrically powered motor vehicle, with an outer surface which faces a cooling device of the electrical energy storage device, and with an inner surface opposite the outer surface which faces a cell winding of the battery cell.

[0011] It is provided that at least one busbar is formed on the inside, which is designed to receive electrical energy from the cell winding, with the cell terminal being cooled via the cooling device.

[0012] In particular, this can improve the cooling of the battery cell, which can, for example, reduce the charging times of electric vehicles and increase safety in the event of a thermal event.

[0013] The invention thus provides for the connection of the electrodes and the current-carrying components to the cooling surface. This allows for an optimized and shortened heat conduction path, as well as the use of high-temperature-resistant insulators. Furthermore, directed degassing and cooling can be achieved, particularly between the respective electrodes or cell terminals.

[0014] This significantly improves heat dissipation from the battery cells. As a result, higher currents can flow for longer periods without exceeding the operating window. This can, for example, lead to reduced charging times. In the event of a thermal event, directed degassing and cooling on the same side prevent overheating of neighboring cells and thus thermal propagation.

[0015] In particular, the invention solves the problem that high currents, for example higher than 5C, are used to achieve the shortest possible charging times. This can lead to significant heat generation in the battery cell and in the current-carrying components. This heat generation can be particularly noticeable in the current collectors, current collectors, and cell terminals. It is already known in the prior art that cooling of the battery cell is usually achieved via a housing surface, preferably at the cell base. For optimized cooling, the thermal connection of the heat-generating components to the cooling surface must be adequately ensured.

[0016] According to the invention, the corresponding electrodes of the cell winding are contacted with the current collectors near the cooling surface. All components in the battery cell that contribute to heat generation are located close to the cooling surface. This allows for short and efficient heat conduction paths between the heat-generating components and the cooling device, including electrical insulation. This enables optimized heat dissipation and thus a reduced charging time.

[0017] According to an advantageous embodiment, a cell terminal for supplying electrical energy is formed on a side part of the cover assembly. For example, the cover assembly can be contacted with the cooling device on its outer surface, and the cell terminal can then be provided on a side part of the cover assembly projecting at an angle of approximately 90 degrees, particularly for drawing electrical energy or for contacting neighboring battery cells. This allows for large-area cooling of the cover assembly while simultaneously ensuring a reliable supply of electrical energy. Furthermore, it has proven advantageous for the busbar to be angled between a current-intake area for the cell winding and a current-output area for the cell terminal. Essentially, the busbar can, for example, have a 90-degree bend.In the current intake area, especially in the area of ​​the cell winding, the current busbar is cooled accordingly, and in the current output area, especially in the area of ​​the cell terminal, it is bent accordingly towards the side part, so that the electrical energy can be reliably delivered.

[0018] It is also advantageous to have a thermal interface material between the inner surface and the busbar. This thermal interface material can be, for example, a thermal paste, a thermal pad, or a thermal gel. This allows for thermal contact between the busbar and the inner surface, and thus the cover. The thermal interface material can also reliably act as an electrical insulator, preventing equipotential bonding between the cover itself and the busbar.

[0019] It is also advantageous if an additional heat-conducting element is formed between the outer surface and the cooling unit. This provides the outer surface with an additional heat-conducting element to ensure a good connection to the cooling unit. This allows the thermal energy from the busbar to be reliably absorbed and dissipated, particularly via the cooling unit, the additional heat-conducting element, the cover itself, and the heat-conducting element.

[0020] It is also advantageous if a cell terminal for supplying electrical energy is located on the outside. This allows both cooling and connection to the busbar's cooling system to be implemented externally, as well as the cell terminal itself. This enables a simple housing design and thus a simpler battery cell construction.

[0021] In another advantageous embodiment, the cover assembly is designed for a housing of a prismatic battery cell. Prismatic battery cells offer a particular advantage over, for example, cylindrical or flat battery cells, as they can be manufactured in various sizes and shapes, which facilitates integration into an electrical energy storage system and enables optimal space utilization. Prismatic battery cells also offer high energy density because they can make optimal use of the available space. They can also be arranged in multiple layers, which further increases the overall energy density. Prismatic battery cells are generally safer than cylindrical cells because they have a more stable housing and a more robust construction. They are also less susceptible to thermal expansion and swelling.Prismatic battery cells are easier to cool than cylindrical battery cells because their larger surface area and generally better thermal conductivity result in less heat generation, thus improving the lifespan and performance of the battery cells. Prismatic battery cells can be easily manufactured in various sizes and capacities, facilitating their scalability. They can also be easily connected in parallel to increase the overall capacity. Prismatic battery cells typically have a longer lifespan than cylindrical battery cells because they are less susceptible to damage from vibration and mechanical stress. They can also be better protected against deep discharge, further extending their lifespan. Prismatic battery cells are generally more environmentally friendly than cylindrical battery cells because they require fewer materials and are easier to recycle.They also have a lower environmental impact during the manufacturing process.

[0022] In summary, prismatic battery cells offer many advantages, including high energy density, safety, cooling, scalability, durability, and environmental friendliness. These advantages make them an attractive option for a wide range of applications, particularly in electric vehicles, stationary energy storage, and industrial applications.

[0023] Another aspect of the invention relates to a housing for a battery cell for an electrical energy storage device of an at least partially electrically powered motor vehicle, comprising at least one housing part for receiving a cell winding and a cover assembly according to the preceding aspect.

[0024] Furthermore, the invention also relates to a battery cell for an electrical energy storage device of an at least partially electrically powered motor vehicle, comprising at least one cell winding and a housing according to the preceding aspect. An advantageous embodiment provides that the battery cell is designed as a prismatic battery cell.

[0025] A further aspect of the invention relates to an electrical energy storage device for a motor vehicle that is at least partially electrically powered, comprising at least one battery cell according to the preceding aspect.

[0026] Furthermore, the invention also relates to a motor vehicle with an electrical energy storage device as described above. The motor vehicle is specifically designed as an at least partially electrically powered vehicle or a fully electric motor vehicle. Advantageous embodiments of the cover assembly are considered advantageous embodiments of the housing, the battery cell, the electrical energy storage device, and the motor vehicle.

[0027] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0028] This shows:

[0029] Fig. 1 shows a schematic side view of an embodiment of a motor vehicle with an embodiment of an electrical energy storage device and an embodiment of a battery cell;

[0030] Fig. 2 shows a schematic sectional view of an embodiment of a battery cell;

[0031] Fig. 3 is a schematic perspective view of an arrangement of the battery cell on an electrical energy storage device; Fig. 4 is another schematic perspective view of a cell winding of a corresponding battery cell;

[0032] Fig. 5 shows a schematic exploded view of an embodiment of a

[0033] Cover assembly for a corresponding battery cell;

[0034] Fig. 6 shows a schematic sectional view of an embodiment according to a

[0035] Battery cell; and

[0036] Fig. 7 shows another schematic sectional view of a further embodiment of a

[0037] Battery cell.

[0038] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0039] Fig. 1 shows a schematic side view of an embodiment of a motor vehicle 10. The motor vehicle 10 is designed, in particular, as an at least partially electrically powered motor vehicle 10 or a fully electric motor vehicle 10. For this purpose, the motor vehicle 10 has an electrical energy storage device 12. The electrical energy storage device 12 is designed to provide electrical energy for an electric drive unit 14. The electrical energy storage device 12 has a plurality of battery cells 16.

[0040] Fig. 2 shows a schematic sectional view of an embodiment of a battery cell 16. The battery cell 16 has at least one housing 18. A cell winding 20 consisting of a plurality of electrodes is arranged in the housing 18. A cooling device 22 for the electrical energy storage device 12 is also shown, including corresponding cooling channels 24.

[0041] Figure 2 further shows, purely schematically represented by a lightning bolt 26, a potential heat generation and a heat conduction path 28 originating from this heat generation. Additionally, electrode current collectors 30 and a corresponding busbar 32 are shown. Furthermore, a thermal conductivity element 34 is shown, which is formed between the housing 18 and the busbar 32. The thermal conductivity element 34 can also be configured as an electrical insulator.

[0042] In particular, Fig. 2 essentially shows a sectional view of a cover assembly 36 for the battery cell 16. The cover assembly 36 has an outer surface 38, which faces the cooling device 22 of the electrical energy storage device 12. The inner surface 40 is also shown, which faces the cell winding 20. The current busbar 32 is formed on the inner surface 40 and is designed to receive electrical energy from the cell winding 20. The current busbar 32 is cooled by the cooling device 22.

[0043] In particular, Fig. 2 shows that heat generation in the area of ​​high currents or high current density is mainly observed at corresponding heat sink foils near the busbar 32 and at the surge arresters 30. The thermal connection of the busbar 32 can be achieved via the thermal interface material, in particular the thermal conductivity element 34, which is also electrically insulating and can, for example, be made of ceramic plates. This allows for very short and efficient heat conduction paths from the heat source to the cooling device 22. Alternatively, the thermal interface material can also consist of or contain thermally conductive adhesive, thermal paste, thermal pads, or thermal gel.

[0044] Figure 3 shows a schematic perspective view of an arranged battery cell 16. It is shown in particular that the cooling device 22 can also be designed as a safety device and can, for example, have a venting channel 42. For this purpose, the cover assembly 36 can, for example, have a corresponding rupture disc 44 (Figure 5) so that hot gases can be discharged into the venting channel 42.

[0045] Fig. 3 further shows that a respective cell terminal 46 for providing electrical energy can be formed on a side part 48 of the cover assembly 36.

[0046] Furthermore, Fig. 3 shows in particular that the cover assembly 36 is designed for a housing 18 of a prismatic battery cell 16. In particular, Fig. 3 also shows that the venting opening, in other words the rupture disc 44, is connected in the cell base to the venting channel 42 on the cooler. This allows hot gases to be dissipated. Heat input and heat dissipation can be achieved via the same side. This prevents local overheating of neighboring cells. Furthermore, relevant cell areas can be cooled without restriction.

[0047] Fig. 4 again shows the cell winding 20 in a perspective view. The different surge arrester tabs or arresters 30 are shown in particular. Fig. 4 shows, for example, that the electrodes can be constructed as two flat windings, with the surge arrester foils leading from one side of a winding. The arresters 30 are then folded inwards from the outer half of the winding. In particular, it can thus be provided that at least two cell windings can be supplied within the battery cell 16. Fig. 4 shows, in particular, a cathode arrester 50 and an anode arrester 52. In particular, the corresponding electrodes can then be welded to the busbar 32, thereby ensuring good accessibility in a tilted position. After welding the cell winding 20, these can be folded together and fixed.This allows for very space-saving and simple contacting as well as good electrical and thermal connection.

[0048] Fig. 5 again shows a schematic exploded view of the cover assembly 36. In particular, a cover element 54 is shown. The cover element 54 has the rupture disc 44 in its center. Furthermore, the heat conducting element 32 is shown in particular, as are the two current busbars 32, for example in the form of the cathode arrester 50 and the anode arrester 52. Fig. 5 shows in particular that, for example, the current busbar 32 is bent between a current receiving area 56 to the cell winding 20 and a current delivering area 58 to the cell terminal 46.

[0049] Fig. 6 again shows a sectional view according to the embodiment already shown in Figs. 2, 3 and 5. Fig. 6 shows in particular that a pole feedthrough leads from the bent current busbar 32 to the cell terminal 46. Furthermore, Fig. 6 shows in particular that an additional heat-conducting element 60 can be formed between the outer surface 38 and the cooling device 22.

[0050] In particular, the contact between the pole bushing and the busbar 32 can be achieved by welding the commutator plate to the pole bushing from the outside. For this purpose, for example, an angle greater than 90 degrees can be provided on the busbar 32 before assembly and elastically deformed during insertion. The spring force ensures tolerance compensation and thus a corresponding zero gap.

[0051] Fig. 7 shows another schematic embodiment of the battery cell 16. Fig. 7 particularly illustrates the embodiment in which the cell terminal 46 for supplying electrical energy is located on the outer surface 38. Specifically, Fig. 7 shows the embodiment in which the cell terminal 46 and the cooling device 22 are arranged on the same side. This allows for optimized use of installation space, particularly by integrating the fill level laterally on the battery cell 16 and the cell contacts within the cooling compartment. The upper terminal bushing shown in Fig. 7 can, of course, be omitted as a redundant terminal bushing, with only the lower terminal bushing being provided.

[0052] In another attractive design variant, the current collector foils are positioned opposite each other laterally and directly connected to the opposing terminal feedthroughs. There are two opposing cover assemblies, each equipped with a terminal feedthrough. The collector plates are connected to the housing via a thermally conductive layer. This is particularly advantageous for long cells, such as so-called blade cells, to achieve better space utilization and a homogeneous current distribution across the electrodes. Reference numeral list

[0053] 10 motor vehicle

[0054] 12 electrical energy storage devices

[0055] 14 Drive unit

[0056] 16 battery cells

[0057] 18 cases

[0058] 20 cell wraps

[0059] 22 Cooling unit

[0060] 24 Cooling channel

[0061] 26 Heat generation

[0062] 28 Heat conduction path

[0063] 30 drains

[0064] 32 busbar

[0065] 34 Heat conducting element

[0066] 36 Cover assembly

[0067] 38 outside

[0068] 40 Inside

[0069] 42 Venting channel

[0070] 44 Burst disc

[0071] 46 cell terminal

[0072] 48 side panel

[0073] 50 cathode dischargers

[0074] 52 anode arresters

[0075] 54 Lid element

[0076] 56 Current consumption range

[0077] 58 Power output range

[0078] 60 additional heat-conducting elements

Claims

Mercedes-Benz Group AG Patent claims 1. Cover assembly (36) for a battery cell (16) of an electrical energy storage device (12) of an at least partially electrically powered motor vehicle (10), with an outer surface (38) which faces a cooling device (22) of the electrical energy storage device (12), and with an inner surface (40) opposite the outer surface (38) which faces a cell winding (20) of the battery cell (16), characterized in that at least one busbar (32) is formed on the inner surface (16) which is designed to receive electrical energy from the cell winding (20), wherein the busbar (32) is cooled via the cooling device (22).

2. Cover assembly (36) according to claim 1, characterized in that a cell terminal (46) for providing electrical energy is formed on a side part (48) of the cover assembly (36).

3. Cover assembly (36) according to claim 2, characterized in that the current busbar (32) is bent between a current receiving area (56) to the cell winding (20) and a current output area (58) to the cell terminal (46).

4. Cover assembly (36) according to one of the preceding claims, characterized in that a heat conducting element (34) is formed between the inside (40) and the power busbar (32).

5. Cover assembly (36) according to one of the preceding claims, characterized in that a further heat conducting element (60) is formed between the outer surface (38) and the cooling device (22).

6. Cover assembly (36) according to one of the preceding claims 1, or 3 to 5, characterized in that a cell terminal (46) for providing the electrical energy is formed on the outside (38).

7. Cover assembly (36) according to one of the preceding claims, characterized in that the cover assembly (36) is designed for a housing (18) of a prismatic battery cell (16).

8. Housing (18) for a battery cell (16) for an electrical energy storage device (12) of an at least partially electrically powered motor vehicle (10), comprising at least one housing part for receiving a cell winding (20) and a cover assembly (36) according to one of claims 1 to 7.

9. Battery cell (16) for an electrical energy storage device (12) of an at least partially electrically powered motor vehicle (10) with at least one cell winding (20) and with a housing (18) according to claim 8.

10. Battery cell (16) according to claim 9, characterized in that the battery cell (16) is designed as a prismatic battery cell (16).

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