DE102021110704A1 - Core for an electric battery cell and electric battery cell - Google Patents

Abstract

The invention relates to a core (10) for an electric battery cell (1), wherein the core (10) has a completely circumferential casing (20) on the outside in cross sections transverse to a longitudinal direction (15) and is elastically deformable at least in sections with respect to forces acting on the outside . The invention also relates to an electric battery cell (1) with such a core (10).

Description

The invention relates to a core for an electric battery cell and an electric battery cell with such a core.

Electric battery cells can be manufactured as cylindrical cells, for example. For example, it can be lithium-ion cells. For example, they can be used as a power supply for electric vehicles. Typically, there is an unusable volume in the middle, which can be filled with a core.

It would be desirable to provide a core that performs alternatively or better than known cores. It would also be desirable to provide an electric battery cell having such a core. According to the invention, this is achieved by a core and an electric battery cell according to the respective independent claims. Advantageous configurations are claimed, for example, in the dependent claims.

The invention relates to a core for an electric battery cell. The core extends along a longitudinal direction. In cross-sections perpendicular to the longitudinal direction, the core expediently has a completely surrounding casing on the outside. The core is expediently elastically deformable, at least in sections, in relation to forces acting on the outside.

Such a core allows the core to react uniformly on all sides to forces acting on it. This can offer an advantage, in particular in comparison with known core shapes whose envelopment is not completely circumferential, since uneven deformation of electrochemical layers wound around the core is prevented. This can extend the service life of an electric battery cell, for example.

Such a core is typically used centrally and/or centrally in an electric battery cell, in particular in a round or cylindrical electric battery cell. The longitudinal direction is typically a straight direction. This can in particular be parallel and/or identical to a longitudinal direction of an electric battery cell in which the core is located. In principle, however, the longitudinal direction can also have a curved or other shape if a more complex shape is to be used.

The cross sections are typically perpendicular to the longitudinal direction at a given location. The specified properties apply to these cross-sections. The formation of a completely surrounding casing on the outside avoids interruptions in this casing, which are often present in designs according to the prior art and can cause inhomogeneity. The casing can have a constant thickness and/or constant material composition and/or constant properties, in particular along the circumference. In particular, the elastic deformability may be independent of location along the circumference, particularly with respect to normal and/or tangential forces.

According to one embodiment, the envelope is a material-homogeneous part of the core. In particular, this can mean that a visual and/or chemical differentiation between the encapsulation and the filling material it encloses is not possible with regard to the material. For example, the core can be made in one piece. Deviations can be provided for this purpose, in particular at the longitudinal ends, which take into account special conditions at the longitudinal ends.

In particular, the core can be elastically deformable by being completely or partially made of an elastically deformable material. This allows the elastic deformability to be provided easily by using a material suitable for this purpose.

According to one embodiment, the core is elastically deformable by being formed entirely or partially from a porous material. A certain deformability can be achieved through the porosity, since the material is given space to evade forces through pores. In particular, this can be combined with the use of elastic and/or deformable materials.

The shell can in particular enclose an inner volume of the core that is hollow or different from the shell in terms of the material. For example, with a hollow interior volume, air may be present within the core. In the case of an inner volume that differs in terms of the material, the inner volume can be specifically formed from a different material than the casing, for example in order to achieve specific properties. A hollow interior volume can be used in particular to save weight.

The core can be elastically deformable, for example, by completely or partially forming the envelope from a porous material. This can relate in particular to the envelope, which, for example, a hollow or regarding the material can enclose differently designed inner volume. For example, the inner volume can be solid, ie not deformable, whereas the encapsulation ensures the deformability.

The core can be elastically deformable, for example, due to the net-like design of the covering. Spaces can also be created in this way, in which existing material can bend in order to achieve the desired elasticity.

The core and/or the shell can be formed from an electrochemically stable material, for example. For example, polyimides, polypropylene, or polyphenylene sulfide can be used. Such materials have proven to be particularly advantageous.

For example, the core can be cylindrical. This allows a particularly advantageous adaptation to a cylindrical electrochemical cell. However, other shapes are also possible. In particular, the cylindrical shape can be interrupted at least in sections at the longitudinal ends and/or at other necessary points in order to take special circumstances at these points into account.

In particular, the core can have a constant cross-section in its entirety or at least along a central section along the longitudinal direction. This enables a simple design, which allows even loading of any surrounding layers. The use of a constant cross-section along a central section can in particular mean that the cross-section remains constant along the central section, which can typically occupy the major part of the length of the core along the longitudinal direction. Deviations can be provided at the respective longitudinal ends, which can, for example, take into account special geometric or other conditions at these longitudinal ends.

For example, the core may be circular or annular in cross-section. Such designs have proven themselves for typical, in particular for cylindrical, battery cells.

For example, the core can be elastic against forces that are transverse to the longitudinal direction or have at least one component transverse to the longitudinal direction. Such forces typically occur in electric battery cells, which in particular can be designed in such a way that the core is surrounded by several layers of electrochemically active material. Such layers may be wrapped around the core in a circular or spiral fashion, for example. If they increase in volume, for example due to thermal expansion, the forces mentioned can occur and be absorbed by the core in an advantageous manner and evenly. This prevents uneven loading of the layers.

The core can be elastically deformable, in particular along the common longitudinal direction, with respect to forces acting on the outside. Such external forces typically occur when the core is surrounded by electrochemical layers as previously described.

The invention further relates to an electric battery cell having a core as described herein and one or more electrochemical layers wrapped around the core. The advantages already described with reference to the core can be achieved by means of such a battery cell. In particular, the layers are evenly loaded due to the all-round encasing of the core, which means that damage can be prevented.

The battery cell can be round on the outside, in particular in cross section. In particular, the core can then also have a circular or ring-shaped cross section. In this way, the geometric shapes of the battery cell and the core work together in a particularly advantageous manner.

An electric battery cell can in particular be an electric energy storage device. This can in particular be a device for storing electrical energy, in particular in order to drive at least one electrical (traction) drive machine. The energy storage device can in particular be formed electrochemically. In particular, several electric battery cells can also be interconnected to form an energy storage device.

• - Zylinderform mit elastischem oder porösem Material,
• - Hohlzylinderform aus elastischem oder porösem Material,
• - netzartige Struktur, insbesondere ringförmig.

In other words, the following versions of a core can be proposed, for example, in order to provide a core for an electric battery cell:

• - Cylindrical shape with elastic or porous material,
• - hollow cylindrical shape made of elastic or porous material,
• - Net-like structure, in particular ring-shaped.

• 1: einen Kern gemäß einem ersten Ausführungsbeispiel in einer perspektivischen Ansicht,
• 2: den Kern von 1 in einer Querschnittsansicht,
• 3: einen Kern gemäß einem zweiten Ausführungsbeispiel in einer perspektivischen Ansicht,
• 4: den Kern von 3 in einer Querschnittsansicht,
• 5: einen Kern gemäß einem dritten Ausführungsbeispiel, und
• 6: eine elektrische Batteriezelle.

The invention will now be described with reference to the figures. show:

• 1 : a core according to a first embodiment in a perspective view,
• 2 : the core of 1 in a cross-sectional view,
• 3 : a core according to a second embodiment in a perspective view,
• 4 : the core of 3 in a cross-sectional view,
• 5 : a core according to a third embodiment, and
• 6 : an electric battery cell.

1 shows purely schematically a core 10 according to a first embodiment. In the present case, the core 10 is made of a homogeneous, elastic material. Alternatively, it could also be made of a porous material, for example. The result of the homogeneity is that an envelope 20 and an inner volume 30 surrounded by it cannot be distinguished from one another with regard to the material. What is relevant, however, is that the cover 20 is continuous along the circumference of the core 10, so that no breaks, cracks or interruptions occur in the cover 20 on the outside. In the present case, this applies along the entire extent of a drawn longitudinal direction 15.

2 10 shows the core 10 in a cross-sectional side view. It can also be seen here that the core 10 is made of a homogeneous material and is therefore not structured internally.

As mentioned, the core 10 is made of an elastic material, so that laterally acting forces can deform it elastically. If the core 10 is used, for example, as a core for an electric battery cell, such forces can act on the core 10 with a component that is transverse to the longitudinal direction 15 . Due to the elastic deformability of the core 10, the forces are at least partially absorbed and this makes it possible, for example, for a certain tolerance to thermal expansion to exist.

3 shows a core 10 according to a second embodiment schematically in a perspective view. It can be seen here that the casing 20 is ring-shaped and encloses a hollow inner volume 40 . This is also shown in the accompanying cross-sectional side view of FIG 4 to see. Such an execution can, for example, compared to the execution of the 1 and 2 weight are saved. Here, too, the cover 20 can be formed, for example, from an elastic and/or porous material in order to achieve the desired properties in a manner similar to that with reference to the statements in FIGS 1 and 2 set described.

5 shows a purely schematic perspective view of a core 10 according to a third embodiment. The casing 20 also surrounds a hollow inner volume 40 and is itself designed like a net. The result of this is that the cover 20 is elastically deformable due to the net-like design. In principle, the same effects can thus be achieved as with reference to the 1 until 4 described.

6 shows purely schematically a battery cell 1 according to an embodiment in a lateral cross-sectional view. In this case, a battery housing 2 is present on the outside, which is designed ring-shaped in cross section and transverse to the plane of the paper 6 extends. A plurality of electrochemical layers 5 are arranged inside the battery housing 2, each of which is ring-shaped in the present case and can ensure the desired properties of electrochemical energy storage. Within the electrochemical layers 5 is a core 10 according to the embodiment of FIG 3 and 4 . As already mentioned, the core 10 is elastically deformable so that, for example, in the event of electrode swelling of the electrochemical layers 5, which can lead to a radially inward pressure on the core 10, this pressure is evenly absorbed by the core 10. In comparison to cores that are not continuous along their circumference, which are known from the prior art, a significantly more uniform loading of the electrochemical layers 5 is thus achieved, which prevents damage and premature aging.

reference list

1

Electric battery cell

2

battery case

5

electrochemical layers

10

core

15

longitudinal direction

20

envelopment

30

internal volume

40

hollow interior volume

Claims (16)

Core (10) for an electric battery cell (1), - wherein the core (10) extends along a longitudinal direction (15), - wherein the core (10) in cross sections transverse to In the longitudinal direction (15) has a completely surrounding casing (20) on the outside, and - the core (10) being elastically deformable at least in sections with respect to forces acting on the outside. core (10) after claim 1 , wherein the covering (20) is a component of the core (10) which is homogeneous in terms of the material. core (10) after claim 1 or 2 wherein the core (10) is elastically deformable by being formed in whole or in part from an elastically deformable material. A core (10) according to any one of the preceding claims, wherein the core (10) is elastically deformable by being formed in whole or in part from a porous material. core (10) after claim 1 , wherein the cladding (20) surrounds an inner volume (30, 40) of the core (10) that is hollow or different from the cladding (20) in terms of material. core (10) after claim 5 , wherein the core (10) is elastically deformable by completely or partially forming the envelope (20) from an elastically deformable material. core (10) after claim 5 or 6 , wherein the core (10) is elastically deformable by completely or partially forming the covering (20) from a porous material. Core (10) according to one of Claims 5 until 7 , wherein the core (10) is elastically deformable by mesh-like formation of the covering (20). Core (10) according to any one of the preceding claims, wherein the core (10) and/or the cladding (20) is formed from polyimides, polypropylene or polyphenylene sulphide. A core (10) according to any one of the preceding claims, wherein the core (10) is cylindrical. Core (10) according to one of the preceding claims, wherein the core (10) has a constant cross-section along the longitudinal direction (15) completely or at least along a central section. A core (10) according to any one of the preceding claims, wherein the core (10) is circular or annular in cross-section. A core (10) according to any one of the preceding claims, wherein the core (10) is resilient to forces transverse to the longitudinal direction (15) or having at least one component transverse to the longitudinal direction (15). Core (10) according to one of the preceding claims, wherein the core (10) is elastically deformable along the entire longitudinal direction (15) in relation to forces acting on the outside. Electric battery cell (1), comprising - a core (10) according to any one of the preceding claims, and - one or more electrochemical layers (5) wound around the core (10). Electric battery cell (1) after claim 15 , wherein the battery cell (1) is round on the outside in cross section.

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