Battery cell arrangement for a high-voltage storage system

Abstract

The invention relates to a battery cell arrangement (15) for a high-voltage storage device (10), comprising a number of battery cells (16), wherein at least one battery cell (16) has a first electrical pole designed as a cell terminal (26) for electrical contact, a second electrical pole (36) for electrical contact and a predetermined breaking point (46) for providing a degassing opening, wherein the cell terminal (26) and the second electrical pole (36) are arranged on a first side of the at least one battery cell (16).

Description

[0001] The invention relates to a battery cell arrangement for a high-voltage storage device, comprising a number of battery cells, wherein at least one battery cell has a first electrical pole designed as a cell terminal for electrical contact, a second electrical pole for electrical contact, and a predetermined breaking point for providing a degassing opening. The invention further relates to a high-voltage storage device for a motor vehicle.

[0002] High-voltage storage systems, also known as traction batteries or accumulators, are used to provide electrical energy for powering electric vehicle drives. A vehicle battery or high-voltage storage system typically comprises battery cells connected in parallel and series, arranged in pack configurations. Electrically conductive cell connectors or cell contact devices can be used to connect the battery cells. These connectors can be connected to the end faces of several battery cells in a cell row of the pack configuration. They typically feature a thermally triggered fuse that melts under a short-circuit current, thus interrupting the current path.

[0003] Since these battery cells can release a considerable amount of energy in the event of a failure, the battery cells of a high-voltage storage system, especially lithium-ion batteries, have predetermined breaking points or vents that serve as a safety mechanism. These vents allow gases to escape that can form under predetermined conditions, such as overcharging, overheating, or an internal short circuit. These high-temperature and high-pressure gases, as well as liquid and solid impurities, must be vented quickly and effectively.

[0004] Against this background, one object of the invention is to improve a battery cell arrangement for a high-voltage storage system or a high-voltage storage system.

[0005] In particular, a battery cell arrangement is to be improved in order to enable improved separation of a cell contacting device in the event of a battery cell failure.

[0006] This problem is solved by a battery cell arrangement for a high-voltage storage device with the features of claim 1, a high-voltage storage device for a motor vehicle with the features of claim 8, and a motor vehicle with the features of claim 10. The dependent claims relate to advantageous further developments of the invention.

[0007] According to a first aspect, a battery cell arrangement for a high-voltage storage device is specified, comprising a number of battery cells, wherein at least one battery cell has a first electrical pole designed as a cell terminal for electrical contacting, a second electrical pole for electrical contacting and a predetermined breaking point for providing a degassing opening, wherein the cell terminal, the second electrical pole and the predetermined breaking point are arranged on a first side of the battery cell.

[0008] This allows, particularly in the event of an electrical short circuit in a battery cell, the predetermined breaking point or a degassing vent of the battery cell to open and disconnect a cell contacting device located on the battery cell, thus interrupting an electrical connection or current flow. The cell contacting device can be disconnected, for example, by mechanical separation, especially due to pressure and / or temperature stress from gases escaping from the degassing vent. This prevents secondary short circuits of adjacent battery cells and thus improves the safety of the battery cell assembly and / or a high-voltage storage system.

[0009] According to another aspect, a high-voltage storage device for a motor vehicle is specified, comprising a battery cell arrangement as described herein, wherein the battery cell arrangement is housed within a casing of the high-voltage storage device. The effects and advantages described herein can be utilized by means of such a high-voltage storage device.

[0010] A high-voltage battery is, in particular, an energy storage device or traction battery for a motor vehicle, comprising multiple battery cells. The housing of the high-voltage battery defines an interior space in which the battery cells or battery cell array are housed. Cylindrical or prismatic battery cells are primarily used, which can be arranged in a cell pack. A cylindrical battery cell, for example, can have a circular cross-section and a longitudinal axis perpendicular to it, and can be bounded longitudinally by two end faces, which are connected by a cell shell or surface. Of course, battery cells with other cross-sections, such as rectangular, hexagonal, or prismatic cross-sections, can also be used.

[0011] In a vehicle installation, the high-voltage storage system and / or battery cells can be arranged such that the longitudinal axes of the battery cells are parallel to a vehicle vertical. Typically, such a battery cell has a geometrically distinct or slightly raised first electrical pole or cell terminal on one of its end faces or first side for electrical contact via the cell contacting device. The remaining part of the end face or first side, as well as the cell shell of the battery cell, can form the second electrical pole of the battery cell. The portion of the end face surrounding the cell terminal, or this area of ​​the second electrical pole, forms a so-called cell shoulder.In other embodiments, particularly in prismatically shaped battery cells, the second electrical pole can also be designed as a separately shaped second cell terminal.

[0012] The invention is based, among other things, on the idea of ​​using a predetermined breaking point or a degassing opening provided by means of the predetermined breaking point to interrupt the current flow to and / or from a damaged or failing battery cell. For this purpose, it is proposed to arrange the degassing opening in the area of ​​the electrical terminals or on an end face of the battery cell, which also has both electrical terminals for contact with a cell contacting device. In particular, a battery cell arrangement with several battery cells is proposed, wherein each of the battery cells has a predetermined breaking point to provide a degassing opening, which is configured to release gases that can form during overcharging, overheating, and / or an internal short circuit as a degassing flow. The predetermined breaking point or...A degassing opening is provided, in particular by means of at least one safety valve and / or predetermined breaking point integrated into the cylindrical battery cell, to release the degassing flow from a predetermined internal pressure, in particular in a controlled manner, without the battery cell itself rupturing or exploding. Such degassing prevents the rising pressure from damaging the internal structures of the battery cell, thus preserving the integrity of the battery cell and reducing the probability of a short circuit and / or other mechanical damage.

[0013] The predetermined breaking point or degassing opening can have a circular or otherwise shaped cross-section on the end face of the battery cell. This prevents other battery cells from being directly exposed to the degassing flow during a degassing process and directs the gas towards the housing. A structural element can be provided between the battery cells and the housing to define a distance between the battery cells and their degassing openings, thus defining a degassing chamber within the high-voltage storage system. This chamber allows the degassing flow to escape to an outlet of the high-voltage storage system and be released into the surrounding environment.

[0014] In one embodiment, the predetermined breaking point is arranged, in particular, radially spaced from the cell terminal. Here, the predetermined breaking point or the degassing opening can be located in a region of a cell shoulder adjacent to the cell terminal, whereby opening of the predetermined breaking point or the degassing opening can cause movement of the cell terminal and thus, in particular, also of a cell contacting device connected to the cell terminal. This can cause, or at least facilitate, a mechanical separation of the cell contacting devices when the predetermined breaking point opens, in order to interrupt current flow between the damaged battery cell or the battery cell opened for degassing and other surrounding or adjacent battery cells.This allows short-circuit currents that can flow from the damaged battery cell to another battery cell to be interrupted, in order to prevent propagation and / or progressive damage to the high-voltage storage system.

[0015] In one embodiment, the predetermined breaking point or degassing opening is located in the area of ​​the second electrical pole or a cell shoulder of the battery cell. The predetermined breaking point can be designed such that a cell contacting device can be arranged at a distance from, or in particular radially outside, the predetermined breaking point on the second electrical pole or the cell shoulder, so that when the predetermined breaking point is triggered, a mechanical separation occurs, particularly in an area of ​​the cell contacting device that contacts the first electrical pole of the damaged battery cell.

[0016] In one embodiment, the battery cell arrangement includes a cell contacting device configured to contact the battery cells at their first and / or second electrical poles. This cell contacting device enables parallel and series connection of these battery cells within a cell assembly. The cell contacting device can be designed as a single unit or in multiple parts to electrically connect a plurality of battery cells, or it can comprise (several) individual contact elements that are electrically and / or mechanically connectable or connected to one another. The respective contact element can be arranged at the end face of the respective battery cell of the high-voltage storage system or its cell terminal and can be designed, in particular, as an electrically conductive track, strip, or sheet metal configured to provide positive and / or negative contacts.To connect the poles of battery cells, in particular across cells and / or cell rows. The cell contacting device can be at least partially integrated into a support structure, in particular a support structure for the battery cells, which can serve at least partially as electrical insulation for the cell contacting device from at least one electrical pole of the battery cell(s).

[0017] In one embodiment, the cell contacting device is arranged on the first side of the battery cells, and thus on the side of the battery cells where the first electrical pole, the second electrical pole, and the predetermined breaking point of the battery cells are located. This allows the cell contacting device to be positioned in the area of ​​the predetermined breaking point of the battery cell while simultaneously contacting the electrical poles of the battery cells. Therefore, if the predetermined breaking point or the vent is triggered, movement of the predetermined breaking point, of the parts of the battery cell located in the area of ​​the predetermined breaking point, and / or the escape of hot gases from the vent, a mechanical separation of the cell contacting device can be caused.

[0018] In one embodiment, the cell contacting device is configured to contact the second electrical pole, particularly radially, outside the predetermined breaking point on the first side of the battery cell. The cell contacting device can form or have at least one arc-segment-shaped contact element, which can be arranged outside the predetermined breaking point on the end face or cell shoulder of the battery cell to make contact. This ensures that the predetermined breaking point or vent is not affected by this contact element or the cell contacting device and / or any connection points, and can open as intended in the event of overpressure in the battery cell. This improves the safety of the battery cell assembly and / or the high-voltage storage system.

[0019] In one embodiment, the cell contacting device has or forms a fracture zone. Such a fracture zone can, in particular, be a mechanical weak point in the form of a cross-sectional reduction and / or at least a recess. The fracture zone can, for example, be formed on a contacting element that is configured to contact a first electrical pole or a recessed cell terminal, such that the fracture zone can be arranged, particularly axially, at a distance from the predetermined breaking point in order to facilitate mechanical separation at the contacting element or the cell contacting device and thus current flow through an opening in the predetermined breaking point.

[0020] In one embodiment, the battery cell arrangement is partially embedded in a structural medium. For example, the first side of the battery cell arrangement, on which the electrical poles, the predetermined breaking point, and / or the cell contacting device are located, can be enclosed by the structural medium to form or provide a uniform, and in particular mechanically robust, structure. This allows the structural medium to prevent or even prevent the propagation of a short circuit through mechanical and / or thermal stabilization. Furthermore, at least a portion of the battery cell arrangement, in particular a section of the lateral surfaces of the battery cells and (end) sides of the battery cells that are opposite the first side of the battery cells, can remain free of the structural medium to simplify the manufacture of the high-voltage storage device and / or to reduce costs.To enable weight loss.

[0021] The triggering of the predetermined breaking point or vent can be influenced by a trigger pressure within the battery cell as well as by mechanical resistances outside the battery cell. To prevent the battery cell from opening at a location other than the predetermined breaking point, the structural medium in the area adjacent to the predetermined breaking point can be designed with a lower density, thickness, and / or structural integrity, and / or by appropriately shaping openings in the support structure.

[0022] According to a further aspect, a motor vehicle is proposed comprising a high-voltage storage system described herein, wherein the cell terminals of the battery cells or the first side(s) of the battery cells are arranged on a side facing away from the vehicle interior. This means that the electrically contacted or contactable poles, as well as the predetermined breaking point and / or the cell contacting device, are arranged facing the environment of the high-voltage storage system or the motor vehicle. As a result, the installation space in the housing of the high-voltage storage system, which is normally kept free for degassing the battery cells, can also be used to absorb forces or loads acting on the underside of the vehicle or on the outside of the housing of the high-voltage storage system.

[0023] Further advantages and application possibilities of the invention will become apparent from the following description in conjunction with the figures. Fig. Figure 1 shows a schematic representation of an embodiment of a motor vehicle according to the invention comprising a high-voltage storage device according to the invention. Fig. Figure 2 shows a schematic representation of an embodiment of a high-voltage storage device according to the invention in accordance with an exemplary embodiment of the invention. Fig. Figure 3 shows a further schematic representation of the embodiment of a high-voltage storage device according to an exemplary embodiment of the invention.

[0024] Fig. Figure 1 shows an embodiment of a motor vehicle 50 with a high-voltage storage device 10 for a motor vehicle 50 with a battery cell arrangement 15 according to the present disclosure in a schematic sectional view in the longitudinal direction of the vehicle.

[0025] The motor vehicle 50 has a high-voltage storage unit 10 in its underbody area, which comprises a housing 11 with a housing cover 12 and a housing tray 13. The housing 11 encloses or delimits an interior space 14 in which a battery cell arrangement 15 of battery cells 16 is arranged. The battery cells 16 are received in the high-voltage storage unit 10 or its housing 11 such that, on a first (end) side of the battery cells 16, recessed cell terminals 26 (first electrical pole) are arranged facing away from the housing cover 12 or a vehicle interior 57 for electrical contact. The remaining part of the first (end) side, or a cell shoulder 36, forms a second electrical pole 36 of the battery cell.In this case, the electrical poles 26, 36 of the battery cells 16 are electrically connected to each other by means of a cell contacting device 18 and the battery cell arrangement 15 is partially (illustrated by the dotted line) embedded in a structural medium 19.

[0026] The battery cell arrangement 15 and the battery cells 16 in connection with the Fig. 2 and Fig. 3 explained in more detail.

[0027] Fig. Figure 2 shows an enlarged detail view of the high-voltage storage unit 10. Fig. 1 in a sectional view along a transverse direction of the vehicle.

[0028] It can be seen that the battery cell arrangement 15 received by the housing 11 is arranged such that the battery cells 16 are spaced apart from the housing 11 by means of a support structure 17, thereby providing a degassing space for the battery cells 16 or the battery cell arrangement 15.

[0029] The battery cell arrangement 15 comprises 16 battery cells, each battery cell 15 having a first electrical pole designed as a cell terminal 26 for electrical contact, a second electrical pole 36 for electrical contact, which in the present embodiment is formed on a cell shoulder surrounding the cell terminal 26, and a predetermined breaking point 46 for providing a degassing opening. The cell terminal 26, the cell shoulder (or the two electrical poles 26, 36), and the predetermined breaking point 46 are arranged on a first side of the battery cell 26. The predetermined breaking point 46 is spaced apart from the cell terminal 26 and is located in the region of the second electrical pole 36.

[0030] Furthermore, the battery cell arrangement 15 has a cell contacting device 18 arranged on the first side of the battery cells 16, which in the present embodiment electrically connects the cell terminal 26 or the first electrical pole of a first battery cell 16 with the second electrical pole 36 of an adjacent battery cell 16. The cell contacting device 18 contacts the second electrical pole 36 radially outside the predetermined breaking point 46 in order not to impede the opening of the predetermined breaking point 46 and thus the release of the degassing opening.

[0031] In the event of overpressure in battery cell 16, the predetermined breaking point 46, or the area of ​​battery cell 16 surrounded or enclosed by the predetermined breaking point 46, in particular including the cell terminal 26, can open and / or detach completely from battery cell 16 (illustrated by an arrow), allowing hot gases and / or particles to escape from battery cell 16. This movement can cause the cell contacting device 18 to experience mechanical separation, thereby interrupting the current flow and protecting surrounding battery cells 16 from overcurrent.

[0032] Fig. Figure 3 shows an enlarged detail view of the high-voltage storage unit 10. Fig. 1 in a schematic top view.

[0033] The battery cells 16 are arranged in a hexagonal packing arrangement and electrically connected by means of the cell contacting device 18. The cell contacting device 18 is at least partially held by a carrier device 21 and positioned or fixed relative to the battery cells 16 or the battery cell arrangement.

[0034] The cell contacting device 18 has a first contacting element 28, which is configured to contact the cell terminal 26 or the first electrical pole of a first battery cell 16. The cell contacting device 18, or the first contacting element 28, forms a fracture zone 48, which in this case is realized by a reduction in cross-section by means of recesses.

[0035] Furthermore, the cell contacting device 18 forms a second contacting element 38, by means of which the second electrical pole 36 or a cell shoulder can be electrically contacted. Here, the second contacting element 38 forms a circular arc segment to contact the second pole 36 outside the predetermined breaking point 46 on the first side of the battery cell 16.

[0036] This allows for a mechanical separation of the cell contacting device 18 or the first contact element 28 in the fracture area 48 if the predetermined breaking point 46 is moved, in order to interrupt the current flow and protect surrounding battery cells 16. This improves the safety of the high-voltage storage unit 10. REFERENCE MARK LIST 10 high-voltage storage units 11 cases 12 Case covers 13 Housing tray 14 Interior of the housing 15 battery cell arrangement 16 battery cells 17 Support structure 18 Cell contacting device 19 Structural medium 21 Supporting institution 26 first electrical pole / cell terminal 28 first contact element 36 second electrical pole / cell shoulder 38 second contact element 46 Breakaway point / Degassing opening 48 Fracture area 50 motor vehicles 57 Vehicle interior

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