A solid-state battery cell for an electric energy storage device of an at least in part electrically operated motor vehicle

Abstract

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

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, wherein the battery cell includes a vascular graft-like polymer mandrel. BACKGROUND INFORMATION

[0002] Human blood vessels are composed of three radial layers and may contract and expand through the action of the muscular middle layer known as the tunica media. According to the state of the art as exemplified in the paper “Fabrication of triple-layered vascular grafts [...],” synthetic vascular grafts can be constructed so as to mimic this behavior of human blood vessels.

[0003] Vascular stents may be inserted in a contracted state into an artery and then expanded so as to provide radial outward pressure on the arterial walls. According to the state of the art as exemplified in document US2009254171AA, a vascular stent may comprise a metal and polymer viscoelastic composite comprising a metal particulate having a particle size greater than about 10 microns and a particle size distribution such that there is an effective amount of particulate in the range of 10 to 70 microns and greater than 70 microns to form the composite and a circularity of greater than 13; as well as a polymer phase; wherein the viscoelastic composite has a tensile elongation of about at least 5%. According to this same document, an electric battery may also comprise such a metal polymer.

[0004] In the construction of a solid-state electric battery from solid electrodes separated by a solid-state electrolyte, high pressure of the layers on each other is desired. This high pressure increases interfacial contact, facilitating the charge-discharge mechanism of the battery. According to the state of the art as exemplified in the paper “Electrolyte melt infiltration for scalable manufacturing of inorganic all-solid-state lithium-ion batteries,” high interfacial contact may be achieved by melting electrolyte to fill crevices in the electrodes. According to the state of the art as exemplified in the paper, “Bipolar stackings high-voltage and high cell level energy density sulfide based all-solid-state batteries,” high interfacial contact may be achieved by the external application of vertically compressive pressure on a cylinder containing repeated stacks of electrodes, electrolytes, and separators. Both techniques present significant manufacturing challenges.

[0005] In the construction of conventional secondary batteries, including but not limited to Lithium-ion batteries and Sodium-ion batteries, that implements anode materials that undergo volume expansion during charge and discharging, including but not limited to Silicon or Silicon containing materials, Tin or Tin containing materials, Graphite or graphite containing materials, coupled with cathode material including but not limited to NMC, NCA, NMCA, LFP, LMFP, LMO, LMNO, which also exhibit volume expansion during charge and discharging. It is well known in both academia and industry that the volume expansion of the materials may need to be controlled and mitigated, with the volume expansion resulting in poor charge transfer ion insertion (Li, Na, etc.), electrolyte depletion, and mechanical dismantling of module / pack mechanical structures leading to catastrophic failure of the electrically operated motor vehicle to name some challenges. Therefore, these issues must be mitigated or else achieving high energy density batteries with stable and safe performance throughout the motor vehicle’s lifetime, is currently and will become greater challenge to overcome. SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to provide a cylindrical battery cell that may be solid-state, quasi-solid-state, semi-solid-state batteries or conventional liquid electrolyte design, with a vascular graft-like polymer mandrel.

[0007] This object is solved by a battery cell according to the independent claim. Advantageous embodiments are presented in the dependent claims.

[0008] One aspect of the present invention relates to a solid-state 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 comprises at least one mandrel.

[0009] It is known to the state of the art that a mandrel may be inserted into a jelly roll in order to increase structural integrity as well as to provide a venting route for gases to escape from the battery. The provision of a venting route mitigates the risk that a gas buildup may result in a breach of the battery housing.

[0010] According to an embodiment, the at least one mandrel is composed at least in part of a polymer material and is configured to increase and / or facilitate increase of radial pressure on the jelly roll after arrangement in the radial center of the jelly roll. The mandrel may include a vascular graft-like polymer mandrel, which may increase and / or facilitate increase of a radial pressure on the jelly roll.

[0011] The use of a polymer material in the construction of the solid-state and liquid electrolyte battery has an advantage of possibly preventing abnormal and erratic runaway events by reducing the risk of puncturing and / or breaking of the battery housing. Unlike metal-based mandrels, polymer mandrels such as plastic mandrels may not transfer enough impact force during an event such as a runaway event to puncture a battery housing, especially a metal one. Therefore, usage of a polymer mandrel may improve the safety of a runaway event.lt is known to the state of the art that a housing or casing may be used to contain and protect at least one component of an electric battery. In this embodiment, the housing may provide a further advantage of a boundary against which the expanding mandrel pushes the jelly roll. By Newton’s third law, this provides a counter-pressure on the jelly roll that results in compression of the jelly roll in a favorable fashion.

[0012] The radially central arrangement of the mandrel within the jelly roll may provide the advantage of ensuring a roughly uniform increase in pressure of the mandrel on the jelly roll across all radial directions away from the mandrel. This has the advantage of minimizing lithium dendrite formation at a given mandrel pressure, because uneven contact between the electrolyte and the electrodes may result in cracks that allow dendrites to form.

[0013] In particular, this embodiment may have the advantage of providing sufficient pressure on the electrode and electrolyte layers so as to achieve proper operation of the charge-discharge mechanism of the solid-state battery. This embodiment has the further advantages of improving the process of manufacturing solid-state batteries and reducing the rate of generation of scrap. By contrast, for example, the bipolar stackings approach mentioned in the background may result in significant scrap from cutting disk-shaped electrolytes, electrodes, and separators.

[0014] Additionally, this embodiment may have the advantage of providing a pressure buffer as the polymer composite may be designed to be able to withstand pressure and changes in morphology in expansion and contraction in the radial, which may help manage the volume / pressure ‘breathing’ that occurs in solid-state and liquid electrolyte batteries during charge and discharge of cylindrical secondary battery cells, thereby also achieving sufficient interfacial contact between the electrode and electrolyte layers necessary for proper operation.

[0015] In this embodiment, a cylindrical solid-state battery cell may be produced in which sufficient operational pressure is provided by a mandrel internal to the battery cell. This may reduce manufacturing complexity and may provide a cylindrical solid-state battery cell of an improved construction, thus solving the challenge introduced earlier.

[0016] According to another embodiment, at least part of the mandrel is configured to receive an expansion agent such as an application of gas pressure.

[0017] For example, the mandrel may comprise a firm but expandable material such that it may be inflated with a gaseous material after the mandrel has been inserted into the jelly roll in a contracted state. Once inflated, the mandrel may be sealed such that its gaseous contents do not escape, except for example by permeation, as when pneumatic tires gradually decline in pressure. Such a seal may be accomplished by, for example, a component analogous to a valve stem in a bicycle tire, which permits the external introduction of additional gas into the mandrel without an escape of gas from within the mandrel.

[0018] The use of gas pressure has the advantage of improving manufacturing. Existing air pump technology may be applied in order to achieve an internal pressure without reliance on an expensive and / or heavy mandrel material.

[0019] According to another embodiment, the expansion agent may include a liquid substance. For example, the mandrel may be configured to receive an injection of at least one liquid substance.

[0020] As in the previous embodiment, the mandrel is here distended outward by an introduction of additional physical contents to the interior of the mandrel. Therefore, a component analogous to the valve stem mentioned earlier may facilitate liquid injection in the case of this embodiment.

[0021] The use of a liquid injection may be advantageous over that of a gas injection in cases where constant pressure is desired. Changes in ambient temperature, for example between seasons, result in gas-filled vessels experiencing uneven internal pressures. The pressure of a liquid is much less responsive to the temperature of the liquid than the pressure of a gas is to the temperature of the gas. As radial pressure on the jelly roll affects the interfacial contact between the layers and therefore the performance of the battery, a liquid injection may be advantageous when particular consistency in battery performance is important.

[0022] According to another embodiment, the mandrel material may include a phasechange material.

[0023] Materials such as water and gallium occupy different volumes depending on the phase in which they exist. For example, since gallium expands as it freezes, a mandrel may be packed with molten gallium before insertion into the jelly roll. As ambient conditions naturally bring the mandrel to room temperature, the gallium freezes and expands, applying increased pressure on the jelly roll. Furthermore, warming of the solidstate battery during operation may bring the solid gallium back to its low melting point, reverting it to a liquid. In this way, the mandrel may naturally oscillate in pressure applied to the jelly roll depending on activity of the electric battery.

[0024] The use of a phase-change material to expand the mandrel may be advantageous by increasing parallelism in a manufacturing chain. For instance, one production line may be established for a series of mandrels filled with molten gallium while another may be established for a series of jelly rolls. After a warmed mandrel is inserted into a jelly roll, a series of remaining battery assembly steps may proceed without an intervening mandrel expansion step, because the mandrel will naturally expand via thermal contact with its cooler surroundings. However, when using a mandrel configured to receive an application of gas pressure, the manufacturing chain must include an additional step between mandrel insertion and the aforementioned remaining battery assembly steps. In this example, the additional step involves an application of gas pressure to the mandrel. Therefore, a phase-change material may facilitate higher manufacturing output of batteries.

[0025] According to another embodiment, at least part of the mandrel is configured for morphological alteration.

[0026] In other words, the mandrel is configured to undergo a physical change in structure involving such steps as reorientation and rearrangement of internal components with relation to each other. For example, an external driving mechanism may be used to drive the mandrel into an expanded state. From this expanded state, the mechanism may then be locked so as to maintain formation when the external force is removed. The externality of the external driving mechanism may be advantageous because it may improve the manufacturing process as an internal driving mechanism may require the production of an additional mechanism for each mandrel produced.

[0027] The use of morphological alteration may be advantageous for the longevity of the electric battery. For instance, gases and liquids used to distend the mandrel may, via permeation, gradually leak into the space occupied by the jelly roll. This may lead to reduced performance of the electric battery over time. By contrast, a morphological mechanism may more readily sustain an expanded state and therefore may maintain performance levels over longer periods of time.

[0028] According to another embodiment, the mandrel expands via an expansion mechanism internal to the mandrel.

[0029] This embodiment has the advantage of facilitating designs where the mandrel is configured to undergo further changes in pressure after achieving an initial expanded state. Deliberate variation in pressure throughout a charge-discharge cycle of the electric battery may improve battery performance and longevity. By contrast, for instance, a mandrel configured to receive an application of gas pressure may either need to remain attached to a gas pressure source or necessitate at least one air pressure intake point of the mandrel accessible from the outside of the electric battery.

[0030] According to another embodiment, the mandrel contains at least one composite material.

[0031] In general, composite materials may combine desirable aspects of each individual component material. For example, an umbrella-like composite of a metallic frame with an interstitial polymer covering may be used to combine an expansion contraption with an even surface. The metallic frame may be driven into an expanded state and locked there, from which point a membrane may serve to distribute the pressure evenly on the jelly roll. As a second example, a rigid material may be used in a port through which a gas or liquid may be passed into a flexible, polymer pouch. The composite material may be a composite of high melting temperature polymer like PTFE, Teflon, Kevlar, blended with glass fiber of 0~50wt.% for example, to provide thermal and mechanical robustness compared to conventionally used battery polymers like PP, PE, or PET.

[0032] This embodiment may be extended by, for example, including a knit pattern of fibers in the construction of the mandrel. According to the state of the art, it is known that a three-layer vascular stent may be used to closely approximate the mechanical properties of a human artery. According to the state of the art, it is furthermore known that among these three-layer vascular stents, at least one layer may comprise a knit pattern of fibers.

[0033] Therefore, an advantageous implementation of this extension of the embodiment may include multiple layers of varying construction in the composition of the mandrel. For example, two layers may be knit according to different patterns in order to achieve a particular collection of physical characteristics, such as compressive stiffness or thermal insulation, for a vascular graft-like mandrel. Alternatively or in addition, one layer may be knit and another woven, according to similar goals.

[0034] According to another embodiment, the mandrel is at least partially hollow. For example, the mandrel may feature a vascular graft-like design with at least one gap along at least one edge of the mandrel. As another example, the mandrel may feature a solid exterior with at least one internal gap.

[0035] The inclusion of at least one gap in the design of the mandrel may reduce battery weights and manufacturing costs, especially when the mandrel material is expensive. The inclusion of at least one gap in the design of the exterior of the mandrel may allow for fine control over the exerted pressure of the mandrel on the jelly roll. This design of the mandrel may afford less rigid operation of the mandrel then would be the case with a solid gapless exterior because this design may dissipate kinetic energy through internal oscillation more robustly than can a continuous solid object.

[0036] According to another embodiment, the jelly roll comprises a laminated stack of at least one anode layer, at least one solid-state electrolyte layer, at least one cathode layer, and at least one separator layer, wherein the stack is rolled into a cylindrical form and arranged inside of the housing.

[0037] According to the state of the art, it is known that lithium-ion batteries may also be produced in prismatic and pouch designs. Cylindrical batteries may be simpler to produce than the other two designs owing to the cylindrical geometry and the standardized manufacturing infrastructure available for this geometry. Furthermore, cylindrical batteries may safely operate in a wider temperature range than may the other two designs, which may contribute to greater environmental versatility of the at least in part electrically operated motor vehicle.

[0038] Another aspect of the present invention relates to a method for manufacturing a solid-state battery or liquid electrolyte 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 comprises at least one mandrel. At least one mandrel is composed at least in part of a polymer material. The mandrel is arranged near the radial center of the jelly roll, wherein the mandrel is in a low-pressure state at the time of arrangement. Radial pressure on the jelly roll is increased radial pressure on the jelly roll by the mandrel.

[0039] In other words, the mandrel is arranged in the jelly roll in a contracted state. This facilitates arrangement by minimizing the displacement necessary for the mandrel to reach its intended location. Alternatively, the mandrel may be arranged prior to the rolling up of the jelly roll. Such an approach would eliminate the need to displace the interior material of the jelly roll.

[0040] Further advantages, features, and details of the present 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

[0041] The novel features and characteristic of the present 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.

[0042] The drawings show in:

[0043] Fig. 1 an exploded view of an embodiment of a solid-state battery cell assembly.

[0044] Fig. 2 a schematic view of a laminated stack of electrodes, electrolyte, and separators as well as a jelly roll counterpart according to an embodiment of a solid-state battery cell.

[0045] Fig. 3 two schematic views of a mandrel expansion according to an embodiment of a solid-state battery cell.

[0046] In the figures the same elements or elements having the same function are indicated by the same reference signs. DETAILED DESCRIPTION

[0047] 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.

[0048] While the present 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.

[0049] 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.

[0050] In the following detailed description of the embodiment of the present 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.

[0051] Fig. 1 shows an exploded view of an embodiment of a solid-state battery cell 10 assembly, here a cylindrical assembly. The jelly roll 12 is inserted into a housing 14, such as an aluminum housing 14, before a mandrel 16, comprising a vascular graft-like inner frame 18 and a polymer membrane 20 attached to the mandrel frame 18, is arranged near the center of the jelly roll 12. In this embodiment, the top and bottom of the cylindrical frame 18 are solid, so that expansion of the membrane is restricted to the radial axis. Once the mandrel 16 is expanded, a terminal 22 may be used to seal the battery cell 10 and to connect the battery cell 10 with at least one other electrical device, for example an electric motor that propels an at least partly electrically operated motor vehicle.

[0052] Other examples of materials used for electric battery housings include steel, rigid plastics, and expanded polypropylene. Other examples of materials used for electric battery terminals include lead, copper, and brass. Polymer materials like, polyethylene, polyethylene terephthalate, polytetrafluoroethylene, Kevlar, Teflon, etc. may be used for the inner frame 18 of the mandrel.

[0053] Fig. 2 shows a schematic view of a laminated stack 24 of electrodes and separators as well as the jelly roll counterpart 12 according to an embodiment of a battery cell 10. At the top and bottom of the laminated stack 24 are separators 26. The second layer from the top comprises a cathode 28. The third layer from the top comprises a solidstate electrolyte 30. The fourth layer from the top comprises an anode 32. In this example, there are only five layers. However, a laminated stack may consist of any number of layers of electrodes, electrolytes, and separators without leaving the scope of this embodiment. The laminated stack 24 is then wound into a spiral known as the jelly roll 12.

[0054] Examples of materials used for separators include rubber, asbestos, polymer films, and cotton fibers. Examples of materials used for cathodes include lithium cobalt oxide, lithium manganese oxide, lithium ion phosphate, and lithium nickel manganese cobalt oxide. Examples of materials used for anodes include graphite, silicon, and metallic lithium. Examples of solid-state electrolytes include ceramics, glass, and sulfides.

[0055] The electrodes 28, 32 and solid state electrolyte 30 may be wound into a jelly roll 12 and may be laminated to a varying degree of lamination to improve interfacial contact even at OMPa. In the case of liquid electrolyte designs, the electrolyte may represent a layer of liquid electrolyte that may be infiltrated into a porous electrode.

[0056] Fig. 3 shows two schematic views of an expansion of the mandrel 16 according to an embodiment of a battery cell 10. The mandrel 16 is configured to receive an expansion agent and to adjust based on events such as a runaway event. In this embodiment, the mandrel 16 consists of a vascular graft-like frame 18 with solid ends over which a membrane is attached 20. Therefore, the mandrel 16 may expands radially outward, exerting a radial pressure 34 on the jelly roll 12 against the housing 14.

[0057] The vascular graft-like design of the mandrel 16 allows for a semi-reversible capability of contraction and expansion. The mandrel 16 in its expanded state may apply a radial force from the radial pressure 34 along the radial direction of the jelly roll 16, and the metal housing 14 of the battery cell 10, other surrounding battery cells 10, and other components of a battery module may be provide pressure support to further improve the interfacial contact between the electrode 38, 32 and solid state electrolyte 30 in the battery cells 10.

[0058] Therefore, the present disclosure may allow the battery cell 10 to adjust to applied pressures during events such as the runaway event, a charge-discharge cycles, or another comparable event in order to facilitate even better battery performance and longevity. reference signs battery cell jelly roll housing mandrel mandrel frame mandrel membrane terminal laminated stack separator cathode solid-state electrolyte anode radial pressure Mercedes-Benz Group AG Felton 2024-09-06

Claims

1. A solid-state battery cell (10) for an electric energy storage device of an at least in part electrically operated motor vehicle, comprising a housing (14), wherein inside of the housing (14) a jelly roll (12) is arranged, and wherein the jelly roll (12) comprises at least one mandrel (16), characterized in thatthe at least one mandrel (16) is composed at least in part of a polymer material and is configured to increase radial pressure (34) on the jelly roll (12) after arrangement near the radial center of the jelly roll (12).

2. The solid-state battery cell (10) according to claim 1, characterized in thatat least part of the mandrel (16) is configured to receive an expansion agent.

3. The solid-state battery cell (10) according to claim 1 or 2, characterized in that at least part of the mandrel (16) is a phase-change material.

4. The solid-state battery cell (10) according to claim 2 or 3, wherein the expansion agent isa liquid substance.

5. The solid-state battery cell (10) according to claim 2 or 3, wherein the expansion agent is air.

6. The solid-state battery cell (10) according to any one of claims 1 to 5, characterized in thatthe mandrel (16) expands via an expansion mechanism internal to the mandrel (16).

7. The solid-state battery cell (10) according to any one of claims 1 to 6, characterized in thatthe mandrel (16) contains at least one composite material.

8. The solid-state battery cell (10) according to any one of claims 1 to 7, characterized in thatthe mandrel (16) is at least partially hollow.

9. The solid-state battery cell (10) according to any one of claims 1 to 8, characterized in thatthe jelly roll (12) comprises a laminated stack (24) of at least one anode layer (32), at least one solid-state electrolyte layer (30), at least one cathode layer (28), and at least one separator layer (26), wherein the stack is rolled into a cylindrical form and arranged inside of the housing (14).

10. A method for manufacturing a solid-state battery cell (10) for an electric energy storage device of an at least in part electrically operated motor vehicle, comprising a housing (14), wherein inside of the housing (14) a jelly roll (12) is arranged, and wherein the jelly roll (12) comprises at least one mandrel (16), comprising the steps of:- composing the at least one mandrel (16) at least in part of a polymer material;- arranging the mandrel (16) near the radial center of the jelly roll (12), wherein the mandrel (16) is in a low-pressure state at the time of arrangement; and- increasing radial pressure (34) on the jelly roll (12) by the mandrel (16).16

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