A battery cell for an electric energy storage device of an at least in part electrically operate motor vehicle

Abstract

A battery cell 10 for an electric energy storage device of an at least in part electrically operated motor vehicle, comprising a housing 12, wherein inside of the housing a jelly roll 14 is arranged,

Description

FIELD OF THE INVENTION

[0001] The present invention relates to the field of automobiles. More specifically, the present invention relates to a battery cell for an electric energy storage device of an at least in part electrically operated motor vehicle. BACKGROUND INFORMATION

[0002] So called mandrels are a commonly used in cylindrical cells by insertion into the center of the jelly roll to serve as a mechanically support for the jelly roll to hold its shape throughout cycling and as a void to serve as evacuation / storage space for generated gas from but not limited to electrochemical reaction, electrolyte degradation, to prevent built up of gas between electrode layers thereby reducing chance of dis-uniform contact, and by extension dis-uniform current distribution &chances for lithium-plating, between the different battery components. During events of thermal runaway, the excessive and violent gas generation quite often drives the mandrels up to the top of the cylindrical housing-can at high speeds and may cause rupture of the cylindrical can housing and lid. This rupture may make the thermal runaway much worse as it leads to expulsion of active material to neighboring cells within the module / pack, thereby accelerating and amplifying the explosive behavior of the cell. Mandrels are not a mandatory design choice but some designs have a mandrel due to the mentioned benefits despite the potential issues related to its implementation. SUMMARY OF THE INVENTION

[0003] It is an object of the invention to provide a battery cell, which allows a secure operation of the battery cell.

[0004] This object is solved 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 electric energy storage device of an at least in part electrically operated motor vehicle, comprising a housing, wherein inside of the housing a jelly roll is arranged, and wherein the jelly roll is wrapped around a mandrel.

[0006] According to an embodiment the mandrel is configured as a polymer material.

[0007] In particular, this has the advantage that the battery cell may prevent abnormal and erratic cell runaway behaviors by eliminating the chance for puncturing and breaking of the cell housing that occurs with using metal or metal based mandrels. By contrast, the polymer mandrels such as plastic mandrels may not have enough impact force during thermal runaway to puncture out from the cell housing and therefore, the cell may undergo normal venting as intended by designs.

[0008] Erratic and random thermal runaways events means that hot gas can also be ejected in random directions so mitigation strategies may be required for all directions of the pack when considering chance for erratic behavior, which leads to added cost, weight, and safety risks. Application of thermal polymer mandrels may reduce the abnormal, erratic thermal runaway behavior to have cells to undergo thermal runaway as the cell design intended. This may reduce the need for additional safety measures like the mica sheet at the cell, module, and / or pack level and / or provide opportunity to adjust the thickness of the modules / pack walls, which usually are made of heavy, durable materials. Furthermore, the battery cell with the polymer mandrel such as a plastic mandrel will behave in a predictable manner and may only vent in the direction it is designed to vent.

[0009] According to an embodiment the polymer material is polytetrafluorethylene

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

[0011] In another embodiment the polymer material is polyetherimides.

[0012] In another embodiment the polymer material is polyether ether ketone.

[0013] In another embodiment, the mandrel may comprise a one-hundred percent composition of the polymer material or a blended composition of the polymer material with other filler materials such as, but not limited to, glass fibers.

[0014] In another embodiment the mandrel comprises a cylindrical form.

[0015] In another embodiment, the mandrel may include at least one of a 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 comprises a thinner material.

[0019] Another aspect of the invention relates to an electrical energy storage device comprising 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 may be configured as an at least in part electrically operated motor vehicle or a fully electrically operated motor vehicle.

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

[0021] Further advantages, features, and details of the invention derive from the following description of preferred embodiments as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and / or shown in the figures alone can be employed not only in the respectively indicated combination but also in any other combination or taken alone without leaving the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The novel features and characteristic 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. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and / or methods in accordance with embodiments of the present subject matter are now described below, by way of example only, and with reference to the accompanying figures.

[0023] The drawings show in:

[0024] Fig. 1 a schematic cross section view according to an embodiment of a battery cell;

[0025] Fig. 2 a schematic cross section view of an embodiment of a mandrel.

[0026] In the figures the same elements or elements having the same function are indicated by the same reference signs. DETAILED DESCRIPTION

[0027] In the present document, the word "exemplary" is used herein to mean "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.

[0028] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawing and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

[0029] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion so that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus preceded by “comprises” or “comprise” does not or do not, without more constraints, preclude the existence of other elements or additional elements in the system or method.

[0030] In the following detailed description of the embodiment of the disclosure, reference is made to the accompanying drawing that forms part hereof, and in which is shown by way of illustration a specific embodiment in which the disclosure may be practiced. This embodiment is described in sufficient detail to enable those skilled in the art to practice 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.

[0031] Fig. 1 shows a schematic cross section a view according to an embodiment of a battery cell 10 for an electrical energy storage device (not shown) of an at least in part electrically operated motor vehicle (not shown). The battery cell 10 may comprise a housing 12. Inside the housing 12 a jelly roll 14 is provided. Furthermore, the battery cell 10 comprise a cover 16, wherein the cover 16 may comprise an electrical pole 18. In particular, Fig. 1 shows the battery cell 10 for the energy storage device of the motor vehicle, comprising the housing 12, where the inside of the housing 12 the jelly roll 14 is arranged, and wherein the jelly roll 14 is wrapped around a mandrel 20. In particular, the mandrel 20 is configured as a polymer material.

[0032] According to an embodiment, the polymer material is polytetrafluoroethylene (PTFE). In some embodiments, the polymer material is configured with glass fiber percentage between zero percent and fifty percent. In a different embodiment, the polymer material may be configured as a polyetherimide. According to another embodiment, the polymer material is polyether ether ketone. The mandrel may include a one-hundred percent composition of a polymer material or a blended composition of the polymer material with other filler materials such as, but not limited to, glass fibers.

[0033] In particular, Fig. 1 shows that the mandrel 20 is a glass fiber reinforced PTFE polymer mandrel 20, and a glass fiber percentage between zero and fifty percent may be provided, which can withstand relatively high temperature and can function as a gas escape route and intended. One advantage of the glass fiber reinforced PTFE polymer mandrel 20 is that the mandrel 20 not be as destructive as a steel mandrel. The present invention is not limited to glass fiber reinforced PTFE and can encompass any high temperature polymers like polyethyleneimine (PEI) and polyether ether ketone (PEEK).

[0034] Fig. 2 shows another 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, the cross sectional view of the mandrel 20 is shown. In particular, Fig. 2 shows that the mandrel 20 may comprise a cylindrical form. The mandrel 20 may be partially open as shown and may comprise an opening 22. Furthermore, it is shown that a tip 24 of the mandrel 20 may be rounded. Furthermore, the tip 24 may include a thinner material.

[0035] In particular, according to Fig. 2, the mandrel 20 design can be a cylindrical tube that is partially open and not completely enclosed. The mandrel 20 design can also be grooved or patterned or textured. The tip 24 of the mandrel 20 may be rounded and made up of a thinner material in order to reduce the rupture of cylindrical cell as a result of mandrel 20 ejection during a thermal runaway event.

[0036] The present solution may allow the mandrel 20 to provide the structural support while also becoming mechanically soft at a higher temperature such as the temperature during a thermal runaway event. During a thermal runaway event, the mandrel 20 may be ejected upwards due to the internal gas built up and the battery cell 10 with the mandrel 20 design may prevent a rupture of the cylindrical housing 12. Reference signs list 10 battery cell 12 housing 14 jelly roll 16 cover 18 pole 20 mandrel 22 opening 24 tip

Claims

1. A battery cell (10) for an electric energy storage device of an at least in part electrically operated motor vehicle, comprising a housing (12), wherein inside of the housing a jelly roll (14) is arranged, and wherein the jelly roll (12) is wrapped around a mandrel (20), characterized in thatthe mandrel (20) is configured as a polymer material.

2. The battery cell (10) according to claim 1, characterized in thatthe polymer material is polytetrafluorethylene.

3. The battery cell (10) according to claim 2, characterized in thatthe polymer material is configured with a glass fiber percentage between 0% and 50%.

4. The battery cell (10) according claim 1, characterized in thatthe polymer material is polyetherimides.

5. The battery cell (10) according claim 1, characterized in thatthe polymer material is polyether ether ketone.

6. The battery cell (10) according claiml, characterized in thatthe mandrel comprises at least one of a groove, texture, or pattern.

7. The battery cell (10) according to any one of claims 1 to 5, characterized in thatthe mandrel (20) comprises a cylindrical form.

8. The battery cell (10) according to claim 6, characterized in thatthe mandrel (20) is partially open.

9. The battery cell (10) according to claim 6 or 7, characterized in thata tip (24) of the mandrel (20) is rounded.

10. The battery cell (10) according to any one of claims 6 to 8, characterized in thata tip (24) of the mandrel (20) comprises a thinner material.

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