Battery cell and motor vehicle

Abstract

The invention relates to a battery unit (6) for a motor vehicle (1) and to a motor vehicle (1) having such a battery unit (5). The battery unit has at least two battery cells (8), which each have a housing (12) enclosing their bulk active material, and which are arranged parallel to one another side by side. Furthermore, the battery unit (6) has a pressure compensation element (16) arranged between the battery cells (8). The housings (12) furthermore have, on the sides facing one another, surface structures (20) which at least protrude toward the respective housing outside, which surface structures are at least partially sunk in the pressure compensation element (16).

Description

Technical Field

[0001] This invention relates to a battery cell. Furthermore, this invention relates to a motor vehicle having such a battery cell. Background Technology

[0002] Battery cells (especially in the form of so-called secondary batteries or rechargeable battery cells) are now increasingly used in the automotive sector to electrify the powertrain, whether in hybrid or fully electric vehicles. Besides the so-called (cylindrical) and prismatic cells, another type of battery cell is the so-called pouch cell. In these pouch cells, electrodes stacked on top of each other, along with the electrolyte and, if necessary, additional components, are arranged in a pouch-like (hence the "pouch") casing formed of a thin film (hereinafter referred to as the "pouch film"). The pouch film is typically deep-drawn into a nearly rectangular shape and sealed (usually welded) with mating parts surrounding the electrodes, etc.

[0003] To form a battery cell, multiple battery cells are typically interconnected. In particular, pouch cells are well-suited for this because their relatively flat structure makes them suitable for stacking. However, a disadvantage is that in this case, they are placed on top of each other with their larger flat sides, thus making cooling through these flat sides difficult. Summary of the Invention

[0004] The purpose of this invention is to improve battery cells.

[0005] This objective is achieved by the battery cell according to the invention. Furthermore, this objective is achieved by the motor vehicle according to the invention. Further advantageous and inventive embodiments and modifications of the invention are set forth in the following description.

[0006] The battery cell according to the invention is designed and installed for use in preferably land-based, and especially wheeled, motor vehicles. The battery cell here has at least two battery cells, each having a housing encapsulating its bulky active material, and the battery cells are arranged parallel to each other, and especially stacked on top of each other. Furthermore, the battery cell has a pressure compensation element disposed between these battery cells. The housings of the two battery cells also have surface structures protruding at least outwards from the respective housing sides (especially flat sides) facing each other, said surface structures being at least partially recessed into the pressure compensation element.

[0007] The "bulk active material" of the corresponding battery cell is preferably a material that facilitates energy storage and / or conduction. In particular, it is an electrode, electrolyte, contact tab, spacer, etc.

[0008] Because the surface structure is at least partially embedded in the pressure compensation element, a relatively small stacking height is achieved in the battery cells. Therefore, structural space can be saved. Furthermore, the surface structure improves cooling performance.

[0009] In a preferred embodiment, the surface structure is formed by the arches of the shell, i.e., by reinforcing ribs (pointing outwards). Thus, compared to a shell without the aforementioned surface structure, there is no "loss" of structural space within the shell for bulk active materials.

[0010] In a preferred embodiment, the battery cell is constructed as a pouch cell. In this case, the casing is formed from a pouch film, particularly from two (half) shells formed by deep drawing of the pouch film. Here, the surface structure is constructed by means of deep drawing, electromagnetic pulse technology, and / or mass forming.

[0011] For example, the surface structure is constructed in a common forming tool during a subsequent deep-drawing step or stamping stroke in which the shell is formed from a soft-film. For instance, the shell is first deep-drawn into a die using a deep-drawing punch. The deep-drawing punch and / or the die has a forming profile corresponding to the surface structure in its face corresponding to the shell base. After completing the (first) deep-drawing step, stamping pressure is then preferably increased by means of the deep-drawing punch for volume forming until at least a portion of the soft-film flows into the profile. Optionally, the deep-drawing punch has an additional, separately movable "lower punch" that only locally increases the stamping pressure or performs additional deep-drawing steps and thus only locally constructs the reinforcing structure. Such a lower punch, for example, is flush with the remaining punch face or retracts at least slightly against the deep-drawing or stamping direction relative to that punch face during the first deep-drawing step.

[0012] In a suitable implementation, the surface structures of the facing sides of the housings are staggered, such that the two housings are arranged with their surface structures alternately engaged. In other words, the surface structure of one housing engages with the surface structure of an adjacent housing or at least is "in a gap" with each other. This allows two adjacent battery cells to be arranged with the smallest possible distance between them.

[0013] In principle, within the scope of the invention, it may also be configured such that the battery cells are pressed against each other to maintain tension, and the surface structure is pressed into the pressure compensation element.

[0014] However, in a preferred embodiment, the pressure compensation element has (particularly intentionally introduced) recesses that correspond to and accommodate surface structures. In other words, the surface structures are recessed into these recesses. For example, these recesses may be milled, stamped, or introduced during the consolidation process of the pressure compensation element.

[0015] In a suitable improvement, cooling channels, particularly those extending on the surface, are additionally introduced into the pressure compensation element (preferably into the aforementioned recess, and optionally, but also alternatively, when the surface structure is pressed into the pressure compensation element). These cooling channels are used to guide the cooling medium along the side faces of the housing.

[0016] In another suitable improvement, the recess is shaped such that a gap exists between the surface structure and the surface of the recess, at least according to the specified assembly condition. This means that the recess has an interference fit, for example, a larger radius than the surface structure. Therefore, the pressure compensation element is not placed on the surface structure or is only partially placed on the surface structure. The remaining gap can also be used to guide the cooling medium.

[0017] In a suitable embodiment, the pressure compensation element has an elastomer and / or a heat-resistant material. The elastomer is, for example, silicone, or (especially thermoplastic) elastomers. The heat-resistant material is preferably an aromatic polyamide, also known as "aramid." For example, the pressure compensation element has a core made of silicone and an outer layer made of aramid, such as an aramid film.

[0018] In another suitable embodiment, the surface structure has a structural height of approximately 1 mm. This means that the arched portion of the housing protrudes 1 mm outward from the "reference surface (i.e., the undeformed surface of the housing)" (plus a tolerance of 5% to 10%). The arched portion is also "recessed" by approximately 1 mm. In this case, the pressure compensation element preferably has a thickness slightly greater than the structural height. This prevents the recess in the pressure compensation element, in particular, from penetrating the pressure compensation element.

[0019] The motor vehicle according to the present invention has the above-described battery cell. In particular, the motor vehicle therefore also has the features and advantages described above. Attached Figure Description

[0020] Embodiments of the present invention will now be explained in more detail with reference to the accompanying drawings. Wherein:

[0021] Figure 1 A schematic side view shows a motor vehicle with a traction battery.

[0022] Figure 2 The battery cells of the traction battery are shown in a schematic partial cross-sectional view, and

[0023] Figure 3 An alternative embodiment of the battery cell of the battery unit is shown in a schematic top view.

[0024] In all the drawings, corresponding parts are always given the same reference numerals. Detailed Implementation

[0025] exist Figure 1 The diagram schematically illustrates a land-based, wheeled motor vehicle, specifically a passenger car 1. The passenger car 1 includes a traction battery 4 for driving and supplying energy to an electric motor 2. The traction battery 4 has multiple battery cells 6. These battery cells 6 further have multiple, i.e., at least two battery cells 8, each battery cell having its corresponding terminal connected to a corresponding associated interface of the battery cell. In the current embodiment, the battery cells 6 are formed, for example, by a so-called battery module having a relatively rigid housing 7 for accommodating the battery cells 8.

[0026] The battery cell 8 is formed from so-called pouch cells, where the bulk active material (e.g., electrodes and electrolyte) of the corresponding battery cell 8 is "encased" in a pouch-like casing 12 formed from a thin film ("pouch film 10"). To form the casing 12, two blanks of the pouch film 10 are each deep-drawn into shell-like structures ("shell 13") and sealed (usually welded) at a surrounding joint 14 while surrounding the bulk active material. Multiple such battery cells 8 are then stacked on top of each other (or fitted side-by-side into the casing of the battery cell 6). So-called pressure compensation elements 16 are inserted between the battery cells 8. These pressure compensation elements are used to compensate for deformation ("breathing") of the battery cell 6 during operation of the traction battery 4 due to heating and the relatively flexible pouch film 10, and to absorb forces directed in the direction of adjacent battery cells 6 due to typically locally different deformations (and thus locally different pressures). The pressure compensation elements 16 are formed from an elastomer and a heat-resistant material, particularly aramid.

[0027] like Figure 2 As shown, surface structures 18 (here in the form of ribs 22 oriented transversely to the longitudinal direction 20) are formed on the corresponding shell 13 (half-shell) of the shell 12. These surface structures are formed into a soft film 10 or the outer side of the shell during a further local deep drawing step of the corresponding shell 13. Figure 2 In the embodiment shown, the ribs 22 of the upward-pointing shell 13 in the image are offset relative to the ribs 22 of the "lower" shell 13. Specifically, the corresponding ribs 22 are positioned over the "gap". This allows the distance between the individual battery cells 8 to be kept relatively small. The ribs 22 increase the surface area of ​​the shell 13, thereby improving cooling of the battery cells 8. Furthermore, the ribs 22 reinforce the shell 13.

[0028] Rib 22 is at least partially recessed into a recess in pressure compensation element 16, specifically into a groove 24 milled into pressure compensation element 16. Groove 24 is dimensionally slightly larger than rib 22. This maintains a gap between rib 22 and groove 24. This allows for at least slight fluctuations in the cooling medium between battery cell 8 and pressure compensation element 16. To further improve cooling, a cooling channel 26 is added to pressure compensation element 16, which also serves to guide the cooling medium.

[0029] exist Figure 3 An alternative embodiment of surface structure 18 is shown. These surface structures are configured here as quadrilateral, such as square, protrusions, "plateaus" 28. The dashed plateaus 28 are intended to indicate the location of the plateaus 28 on the back side of the shell 13 as a hidden edge. Furthermore, the pressure compensation element 16 in this embodiment is similar to Figure 2 Construction. For example, in the current embodiment, the cooling channel 26 meanders around the boss 28 or extends in a straight line through the spaces between these bosses.

[0030] The subject matter of this invention is not limited to the embodiments described above. Rather, those skilled in the art can deduce other embodiments of the invention from the above description. In particular, the various features and design variations of the invention described with reference to different embodiments can also be combined with each other in other ways.

[0031] List of reference numerals

[0032] 1 Passenger vehicles

[0033] 2 Electric motor

[0034] 4 Traction Battery

[0035] 6 battery cells

[0036] 7. Casing

[0037] 8 battery cells

[0038] 10 Flexible film

[0039] 12. Shell

[0040] 13 shells

[0041] 14 Joint

[0042] 16 Pressure compensation elements

[0043] 18 Surface Structure

[0044] 20. Vertical direction

[0045] 22 ribs

[0046] 24 Grooves

[0047] 26 Cooling Channels

[0048] 28. Protrusion.

Claims

1. A battery cell (6) for a motor vehicle (1), having - At least two battery cells (8), each battery cell having a shell (12) encapsulating its bulk active material, and the battery cells being arranged parallel to each other side by side. - Pressure compensation elements (16) arranged between the battery cells (8), wherein The housing (12) has surface structures (20) protruding at least toward the corresponding outer side of the housing on its respective sides facing each other, the surface structures being at least partially recessed in the pressure compensation element (16), wherein the surface structures (20) are formed by the arches of the housing (12), wherein the battery cell (8) is constructed as a pouch cell, wherein the surface structures (20) of the sides of the housing (12) facing each other are staggered such that the two housings (12) are arranged with the surface structures (20) alternately engaged, wherein the pressure compensation element (16) has a corresponding recess (24) for receiving the surface structures (20), wherein additionally, surface-extending cooling channels (26) are introduced into the pressure compensation element (16) for guiding cooling medium along the sides of the housing (12).

2. The battery cell (6) according to claim 1, wherein In the soft film (10) that forms the corresponding housing (12), the surface structure (20) is constructed by means of deep drawing and / or bulk forming.

3. The battery cell (6) according to claim 1 or 2, wherein The recess (24) is shaped such that, at least in the prescribed assembly state, there is a gap between the surface structure (20) and the surface of the recess (24).

4. The battery cell (6) according to claim 1 or 2, wherein The pressure compensation element (16) has an elastomer and / or a heat-resistant material.

5. The battery cell (6) according to claim 1 or 2, in, The surface structure (20) has a structural height of 1 mm.

6. The battery cell (6) according to claim 5, wherein The pressure compensation element (16) has a thickness that is slightly greater than the height of the structure.

7. A motor vehicle (1) having a battery cell (6) according to any one of claims 1 to 6.

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