Battery cell for an electrical energy storage device of an at least partially electrically powered motor vehicle

Abstract

The invention relates to a battery cell (10) for an electrical energy storage device of an at least partially electrically operated motor vehicle, comprising a housing (12), wherein a jelly roll (14) is arranged inside the housing, and wherein the jelly roll (12) is wound around a mandrel (20), characterized in that the mandrel (20) is designed as a polymeric material.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to the field of motor vehicles. In particular, the present invention relates to a battery cell for an electrical energy storage device of an at least partially electrically powered motor vehicle. BACKGROUND INFORMATION

[0002] Mandrels are commonly used in cylindrical cells, inserted into the center of the jelly roll to provide mechanical support for the jelly roll, helping it maintain its shape during cycling, and as a cavity that acts as an evacuation / storage space for the gas generated by the electrochemical reaction and electrolyte degradation. This helps prevent gas accumulation between the electrode layers, thereby reducing the risk of uneven contact and, consequently, uneven current distribution and the risk of lithium plating between the various battery components. During thermal runaway, the excessive and violent gas evolution often propels the mandrels at high speed to the top of the cylindrical casing and can cause the cylindrical casing and lid to fracture.This fracture can further exacerbate thermal runaway by causing the ejection of active material into neighboring cells within the module / pack, accelerating and amplifying the cell's explosive behavior. Mandrels are not a mandatory design choice, but some designs incorporate a mandrel due to the aforementioned advantages, despite the potential problems associated with its implementation. SUMMARY OF THE INVENTION

[0003] It is an object of the invention to provide a battery cell which enables safe operation of the battery cell.

[0004] This object is achieved by a battery cell according to the independent claim. Advantageous embodiments are presented in the dependent claim.

[0005] One aspect of the invention relates to a battery cell for an electrical energy storage device of an at least partially electrically operated motor vehicle, comprising a housing, wherein a jelly roll is arranged inside the housing, and wherein the jelly roll is wound around a mandrel.

[0006] In one embodiment, the mandrel is made of polymer material.

[0007] This has the particular advantage of preventing abnormal and erratic cell runaway behavior by eliminating the risk of puncturing and rupturing the cell casing, which is inherent in the use of metal or metal-based mandrels. In contrast, polymer mandrels, such as plastic mandrels, may not have sufficient impact force to puncture the cell casing during thermal runaway, and therefore the cell can vent normally, as intended by design.

[0008] Irregular and random thermal runaways mean that hot gas can also be ejected in random directions, so mitigation strategies may be required for all directions of the pack, considering the possibility of irregular behavior, leading to additional cost, weight, and safety risks. The use of thermal polymer mandrels can reduce abnormal, irregular thermal runaway behavior, allowing cells to thermally runaway as intended by the cell design. This can reduce the need for additional safety measures such as mica foil at the cell, module, and / or pack level and / or provide the opportunity to adjust the thickness of the module / pack walls, which are usually made of heavy, durable materials. In addition, with the polymer mandrel, the battery cell behaves more reliably, e.g.a plastic mandrel, in a predictable manner and vents only in the direction for which it is designed.

[0009] In one embodiment, the polymer material is polytetrafluoroethylene.

[0010] In another embodiment, the polymer material is configured with a glass fiber content of between zero and fifty percent.

[0011] In another embodiment, the polymer material is polyetherimide.

[0012] In another embodiment, the polymer material is a polyetheretherketone.

[0013] In another embodiment, the mandrel may be composed of a 100% composition of the polymer material or a mixed composition of the polymer material with other filler materials, such as glass fibers.

[0014] In another embodiment, the mandrel has a cylindrical shape.

[0015] In another embodiment, the mandrel may have at least one groove, texture, or pattern.

[0016] In another embodiment, the mandrel is partially open.

[0017] In another embodiment, a tip of the mandrel is rounded.

[0018] In another embodiment, a tip of the mandrel is made of a thinner material.

[0019] A further aspect of the invention relates to an electrical energy storage device having at least one battery cell according to the preceding aspect. Furthermore, the present invention relates to a motor vehicle comprising at least one electrical energy storage device according to the preceding aspect. The motor vehicle can be designed as an at least partially electrically powered motor vehicle or as a fully electrically powered motor vehicle.

[0020] Advantageous embodiments of the battery cell are to be regarded as advantageous embodiments of the electrical energy storage device and of the motor vehicle.

[0021] 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 in the following description of the figures and / or illustrated alone in the figures, can be used not only in the respective combinations specified, but also in any other combination or alone, without departing from the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The novel features and characteristics of the disclosure are set forth in the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, serve to explain the disclosed principles. Throughout the figures, like numerals are used to refer to like features and components. Some embodiments of systems and / or methods according to embodiments of the present subject matter are described below, by way of example only, and with reference to the accompanying figures.

[0023] The drawings show in: Fig. 1: Schematic cross-section through a battery cell according to an embodiment; Fig. 2: Schematic cross-section of a mandrel embodiment.

[0024] In the illustrations, identical elements or elements with the same function are identified by the same reference symbols. DETAILED DESCRIPTION

[0025] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0026] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will be described in detail below. It should be understood, however, that the disclosure is not intended to be limited to the particular forms, but on the contrary, will cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

[0027] The terms "comprises," "including," or other variations thereof are intended to cover non-exclusive inclusion, such that an assembly, device, or method comprising a list of components or steps not only includes those components or steps, but may also include other components or steps not expressly listed or included in such assembly, device, or method. In other words, one or more elements in a system or device preceded by the phrase "comprises" or "comprising" do not preclude, without further limitation, the presence of other elements or additional elements in the system or method.

[0028] In the following detailed description of the embodiment of the disclosure, reference is made to the accompanying drawings, which form a part of the disclosure, and in which is shown by way of illustration a specific embodiment in which the disclosure may be practiced. This embodiment has been described in sufficient detail to enable those skilled in the art to utilize the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is therefore not to be taken in a limiting sense.

[0029] Fig. 1 shows a schematic cross-sectional view of an embodiment of a battery cell 10 for an electrical energy storage device (not shown) of an at least partially electrically powered motor vehicle (not shown). The battery cell 10 may comprise a housing 12. A jelly roller 14 is provided inside the housing 12. Furthermore, the battery cell 10 may have a cover 16, wherein the cover 16 may have an electrical pole 18. Fig. 1 shows, in particular, the battery cell 10 for the energy storage device of the motor vehicle, comprising the housing 12, wherein the jelly roll 14 is arranged inside the housing 12, and wherein the jelly roll 14 is wound around a mandrel 20. In particular, the mandrel 20 is formed as a polymer material.

[0030] According to one embodiment, the polymer material is polytetrafluoroethylene (PTFE). In some embodiments, the polymer material is configured with a glass fiber content between zero percent and fifty percent. In another embodiment, the polymer material may be embodied as polyetherimide. According to another embodiment, the polymer material is a polyetheretherketone. The mandrel may contain a 100 percent composition of a polymer material or a blended composition of the polymer material with other filler materials, such as glass fibers.

[0031] In particular, Fig. 1, the mandrel 20 is a glass fiber-reinforced PTFE polymer mandrel, with a glass fiber content of between zero and fifty percent, which can and should withstand relatively high temperatures and function as a gas escape path. An advantage of the glass fiber-reinforced PTFE polymer mandrel 20 is that the mandrel 20 is not as destructive as a steel mandrel. The present invention is not limited to glass fiber-reinforced PTFE and can include all high-temperature polymers such as polyethyleneimine (PEI) and polyetheretherketone (PEEK).

[0032] Fig. Figure 2 shows a further schematic cross-section or view according to an embodiment of the mandrel 20. In particular, on the left side of Fig. 2 the mandrel 20 is shown in a side view, and on the right side of Fig. 2 shows the cross-sectional view of the mandrel 20. Fig. In particular, Figure 2 shows that the mandrel 20 may have a cylindrical shape. The mandrel 20 may be partially open, as shown, and include an opening 22. Furthermore, it is shown that a tip 24 of the mandrel 20 may be rounded. Furthermore, the tip 24 may be made of a thinner material.

[0033] In particular, the mandrel 20 can be Fig. 2 may be designed as a cylindrical tube that is partially open and not completely closed. The shape of the mandrel 20 may also be grooved, patterned, or textured. The tip 24 of the mandrel 20 may be rounded and made of a thinner material to reduce breakage of the cylindrical cell due to ejection of the mandrel 20 during thermal runaway.

[0034] The present solution may allow the mandrel 20 to provide structural support while becoming mechanically soft at a higher temperature, e.g., the temperature during thermal runaway. During thermal runaway, the mandrel 20 may be propelled upward due to the gas forming inside, and the battery cell 10 with the mandrel 20 may prevent the cylindrical housing 12 from rupturing. List of reference symbols 10 battery cells 12 housings 14 Jelly Roll 16 Cover 18 bars 20 thorn 22 Opening 24 lace

Claims

[1] A battery cell (10) for an electrical energy storage device of an at least partially electrically operated motor vehicle, comprising a housing (12), wherein a jelly roll (14) is arranged inside the housing, and wherein the jelly roll (12) is wound around a mandrel (20), characterized by that the mandrel (20) is formed as a polymer material. [2] The battery cell (10) according to claim 1, characterized by that the polymer material is polytetrafluoroethylene. [3] The battery cell (10) according to claim 2, characterized by that the polymer material is configured with a glass fiber content between 0% and 50%. [4] The battery cell (10) according to claim 1, characterized by that the polymer material is polyetherimide. [5] Battery cell (10) according to claim 1, characterized by that the polymer material is polyetheretherketone. [6] The battery cell (10) according to claim 1, characterized bythat the mandrel has at least one groove, texture or pattern. [7] Battery cell (10) according to one of claims 1 to 5, characterized by that the mandrel (20) has a cylindrical shape. [8] Battery cell (10) according to claim 6, characterized by that the mandrel (20) is partially open. [9] Battery cell (10) according to claim 6 or 7, characterized by that a tip (24) of the mandrel (20) is rounded. [10] Battery cell (10) according to one of claims 6 to 8, characterized by that a tip (24) of the mandrel (20) is made of a thinner material.

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