Patent Application
20250158077
This application claims the benefit of Chinese Patent Application No. 202311514978.5 filed on Nov. 14, 2023. The entire disclosure of the application referenced above is incorporated herein by reference.
The information provided in this section is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
The present disclosure relates to cathode electrodes for battery cells, and more particularly to multi-functional cathode current collectors for nickel-rich cathode electrodes.
Electric vehicles (EVs) such as battery electric vehicles (BEVs), hybrid vehicles, and/or fuel cell vehicles include one or more electric machines and a battery system including one or more battery cells, modules, and/or packs. A power control system is used to control charging and/or discharging of the battery system during charging and/or driving.
Battery cells include cathode electrodes, anode electrodes, and separators. The cathode electrodes include a cathode active material layer (including cathode active material) arranged on a cathode current collector. The anode electrodes include an anode active material layer (including anode active material) arranged on an anode current collector.
A cathode electrode includes a multi-functional cathode current collector including a cathode current collector and a layer including a positive temperature coefficient (PTC) material arranged adjacent to the cathode current collector. A cathode active material layer is arranged on the multi-functional cathode current collector and includes a cathode active material including nickel.
In other features, the cathode active material comprises a rock salt layered oxide including nickel. The cathode active material is selected from a group consisting of LiNixMnyCo1-x-yO2, LiNxCoyAl1-x-yO2, LiNixCoyMnzAl1-x-y-zO2, LiNixMnyAl1-x-yO2, LiNixMn1-xO2, and LiNiO2, where x, y, and z are in a range from 0 to 1.
In other features, the cathode current collector is made of at least one of aluminum and stainless steel. A thickness of the multi-functional cathode current collector is in a range from 4 μm to 30 μm. The layer includes a PTC layer including the PTC material and a polymer arranged on the cathode current collector and a conductive layer arranged on the PTC layer and including a conductive additive and a hot adhesive polymer.
In other features, the layer includes a conductive layer including a conductive additive and a polymer arranged on the cathode current collector and a PTC layer arranged on the conductive layer and including the PTC material and a hot adhesive polymer.
In other features, the layer further includes a hot adhesive polymer. The layer further includes a conductive additive and a hot adhesive polymer. The conductive additive is selected from a group consisting of a carbon-based conductive additive, an oxide-based conductive additive, a carbide, and a silicide. The cathode active material comprises 70 to 99 wt % of the cathode active material layer, a conductive additive comprises 0.5 wt % to 20 wt % of the cathode active material layer, and a binder comprises 0.5 wt % to 10 wt % of the cathode active material layer.
In other features, the PTC material is doped with one or more materials selected from a group consisting of lanthanum (La), cesium (Ce), tin (Sb), yttrium (Y), tungsten (W), titanium (Ti), tantalum (Ta), niobium (Nb), cobalt (Co), chlorine (CI), iodine (I), and bromine (Br). The PTC material comprises at least one of BaTIO3 and a V2O5-based PTC material.
In other features, a room temperature (RT) resistance of the PTC material is less than 50 ohm-meter, and a Curie temperature of the PTC material is in a range from 80° C. to 200° C. A ratio of resistance of the PTC material at the Curie temperature divided by resistance of the PTC material at room temperature is greater than 100.
A cathode electrode includes a multi-functional cathode current collector including a cathode current collector made of at least one of aluminum and stainless steel and a layer including a positive temperature coefficient (PTC) material and a hot adhesive polymer arranged adjacent to the cathode current collector. A cathode active material layer is arranged on the multi-functional cathode current collector and includes a cathode active material including a rock salt layered oxide including nickel.
In other features, the layer includes a PTC layer including the PTC material and a polymer and a conductive layer arranged on the PTC layer and including a conductive additive and a hot adhesive polymer. The layer includes a conductive layer including a conductive additive and a polymer and a PTC layer arranged on the conductive layer and including the PTC material and a hot adhesive polymer. The layer further includes a conductive additive.
Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:
In the drawings, reference numbers may be reused to identify similar and/or identical elements.
While battery cells according to the present disclosure are shown in the context of electric vehicles, the battery cells can be used in stationary applications and/or other applications.
As described above, battery cells include cathode electrodes, anode electrodes, and separators arranged in an enclosure. The cathode electrodes include a cathode active material layer (including cathode active material) arranged on a cathode current collector. In some examples, the cathode active material layer includes nickel-rich (Ni-rich) cathode active material. Ni-rich cathode active materials such as NCMA, NCA and NMC811 are thermally unstable since they decompose below 300° C. and generate molecular oxygen (O2). When O2 is released, it reacts with flammable cell contents and increases the likelihood of thermal events such as thermal runaway.
The present disclosure relates to cathode electrodes including multi-functional cathode current collectors and Ni-rich cathode active material. The multi-functional cathode current collector includes a conductive filler (e.g., carbon black), a polymer, a hot adhesive polymer (e.g., PE-EVA), and/or a positive temperature coefficient (PTC) material (e.g., BaTiO3). In some examples, the cathode current collector is used for a cathode electrode including a cathode active material comprising a Ni-rich cathode material and polytetrafluoroethylene (PTFE) binder. The multi-functional current collector prevents thermal runaway events by increasing the resistance of the cathode current collector by a factor of around 5×105 at 100° C. as compared to the resistance of the cathode current collector at a lower temperature such as 36° C. The increased resistance blocks an electron flow path of the cathode active material layer to the cathode current collector to enhance thermal stability without sacrificing electrochemical performance at lower temperatures (e.g., normal operating temperature).
Referring now to
The A anode electrodes 40-1, 40-2, . . . , and 40-A include anode active material layers 42 arranged on one or both sides of the anode current collectors 46. In some examples, the anode active material layers 42 and/or the cathode active material layers 24 are free-standing electrodes that are arranged adjacent to (or attached to) the multi-functional cathode current collectors 26 and/or the anode current collectors 46, respectively. In some examples, the anode active material layers 42 and/or the cathode active material layers 24 comprise coatings or freestanding film including one or more active materials, one or more conductive fillers/additives, and/or one or more binder materials that are applied to the current collectors.
In some examples, the multi-functional cathode current collector 26 and the anode current collectors 46 comprise metal foil, metal mesh, perforated metal, 3 dimensional (3D) metal foam, and/or expanded metal. In some examples, the anode current collectors 46 are made of one or more materials selected from a group consisting of copper, stainless steel, brass, bronze, zinc, aluminum, and/or alloys thereof. In some examples, the multi-functional cathode current collectors 26 are made of one or more materials selected from a group consisting of stainless steel and aluminum. In some examples, the cathode current collector 26 has a thickness in a range from 4 μm to 30 μm. In some examples, the cathode current collector 26 has a thickness in a range from 6 μm to 20 μm. External tabs 28 and 48 are connected to the current collectors of the cathode electrodes and anode electrodes, respectively, and can be arranged on the same or opposite sides of the battery cell stack 12. The external tabs 28 and 48 are connected to terminals of the battery cells.
Referring now to
In
In
In
In the cathode electrodes in
In other examples, the cathode electrodes are manufactured using wet coating and the hot adhesive polymer (used to provide adhesion to the free-standing film) is omitted. In other words, the outermost layer of the multi-functional cathode current collector does not include the hot adhesive polymer and the cathode active material layer is cast on the cathode current collector. For example, a cathode active material (e.g., NCMA), a binder (e.g., polyvinylidene difluoride (PVDF)), and an optional conductive additive are mixed with a solvent, cast onto the multi-functional cathode current collector, and dried.
Referring now to
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Referring now to
In
The cathode electrodes delivered approximately the same performance. The conventional battery cell 310 had a charge capacity loading of 5.76 mAh/cm2, a discharge capacity loading of 4.99 mAh/cm2, and a columbic efficiency of 86.6%. The battery cell including the cathode electrode with the multi-functional cathode current collector had a charge capacity loading of 5.71 mAh/cm2, a discharge capacity loading of 4.95 mAh/cm2, and a columbic efficiency of 86.7%.
In
In some examples such as those in
In some examples such as those in
In some examples, the conductive additive is selected from a group consisting of a carbon-based conductive additive, an oxide-based conductive additive, a carbide, and a silicide. Examples of carbon-based conductive additive include carbon black, graphite, graphene, graphene oxide, Super P, acetylene black, carbon nanofiber, carbon nanotubes, and other electronically conductive additives. Examples of oxides include simple oxides and superconducting oxides. Examples of simple oxides include ruthenium oxide RuO2, tin oxide (SnO2), zinc oxide (ZnO), and germanium oxide (Ge2O3). Examples of superconducting oxides include yttrium barium copper oxide (YBCO or YBa2Cu3O7) and La0.75Ca0.25MnO3. An example of a carbide includes silicon carbide (SiC2). An example of a silicide includes molybdenum disilicide (MoSi2).
In some examples, the polymer is selected from a group consisting of polyurethane (PU), polyamide (PA), polyethylene (PE), PE-(ethylene vinyl acetate) EVA, polyacrylic acid (PAA), polyvinyl chloride (PVC), and combinations thereof. In some examples, the polymer comprises a hot adhesive polymer.
In some examples, the PTC material is selected from a group consisting of an inorganic PTC material and an organic PTC material. Examples of inorganic PTC material include BaTIO3 and a V2O5-based PTC material. In some examples, the PTC material is doped to alter a Curie temperature of the PTC material. In some examples, the dopant comprises one or more materials selected from a group consisting of (lanthanum (La), cesium (Ce), tin (Sb), yttrium (Y), tungsten (W), titanium (Ti), tantalum (Ta), niobium (Nb), cobalt (Co), chlorine (CI), iodine (I), and/or bromine (Br)). In some examples, an oxide additive such as SiO2 or Al2O3 is added.
In some examples, a Curie temperature of the PTC material is in a range from 80° C. to 200° C. In some examples, a Curie temperature of the PTC material is in a range from 90° C. to 120° C. In some examples, room temperature (RT) resistance of the PTC material is less than 50 ohm-meter (ohm·m). In some examples, room temperature (RT) resistance of the PTC material is less than 10 ohm·m. In some examples, a ratio of resistance at the Curie temperature divided by resistance at room temperature is greater than 100. In some examples, a ratio of resistance at the Curie temperature divided by resistance at room temperature is greater than 1000.
In some examples, the cathode active material comprises 70 to 99 wt % % of the cathode active material layer, the conductive additive comprises 0.5 wt % to 20 wt % of the cathode active material layer, and the binder comprises 0.5 wt % to 10 wt % of the cathode active material layer. In some examples, the cathode active material includes Ni-rich rock salt layered oxides. Examples of Ni-rich rock salt layered oxides include LiNixMnyCo1-x-yO2 (NMC) 811, LiNxCoyAl1-x-yO2 (NCA), LiNixCoyMnzAl1-x-y-zO2 (NCMA), LiNixMnyAl1-x-yO2 (NMA), LiNixMn1-xO2 (NM), and LiNiO2 (LNO).
The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.
Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
In the figures, the direction of an arrow, as indicated by the arrowhead, generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, for information sent from element A to element B, element B may send requests for, or receipt acknowledgements of, the information to element A.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023115149785 | Nov 2023 | CN | national |
