Battery cell comprising a multifunctional current collector

Abstract

The present invention provides a cathode electrode comprising a multifunctional cathode current collector comprising a cathode current collector and a layer comprising a positive temperature coefficient (PTC) material disposed adjacent to the cathode current collector. The cathode active material layer is disposed on the multifunctional cathode current collector and includes a nickel-containing cathode active material.

Description

Technical Field

[0001] The present disclosure relates to cathode electrodes for battery cells, and more particularly to multifunctional cathode current collectors for nickel-rich cathode electrodes. Background Art

[0002] The information provided in this section is intended to generally introduce the background of the present disclosure. To the extent that work currently named as inventors is described in this section, and aspects of the specification that may not have been otherwise identified as prior art at the time of filing, are not admitted, either explicitly or implicitly, as prior art to the present disclosure.

[0003] The present disclosure relates to cathode electrodes for battery cells, and more particularly to multifunctional cathode current collectors for nickel-rich cathode electrodes.

[0004] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles, include one or more motors and a battery system including one or more battery cells, modules, and / or battery packs. A power control system is used to control the charging and / or discharging of the battery system during charging and / or driving.

[0005] The battery cell includes a cathode electrode, an anode electrode and a separator. The cathode electrode includes a cathode active material layer (including cathode active material) disposed on a cathode current collector. The anode electrode includes an anode active material layer (including anode active material) disposed on an anode current collector. Summary of the invention

[0006] The cathode electrode includes a multifunctional cathode current collector including a cathode current collector and a layer containing a positive temperature coefficient (PTC) material disposed adjacent to the cathode current collector. The cathode active material layer is disposed on the multifunctional cathode current collector and includes a cathode active material containing nickel.

[0007] In other features, the cathode active material comprises a nickel-containing rock salt layered oxide. The cathode active material is selected from LiNi x Mn y Co 1-x-y O2、LiN x Co y Al 1-x-y O2、LiNi x Co y Mn z Al 1-x-y-z O2、LiNi x Mn y Al 1-x-y O2、LiNi x Mn 1-xO2 and LiNiO2, where x, y and z are in the range of 0 to 1.

[0008] In other features, the cathode current collector is made of at least one of aluminum and stainless steel. The multifunctional cathode current collector has a thickness of 4 μm to 30 μm. The layers include a PTC layer comprising a PTC material and a polymer disposed on the cathode current collector and a conductive layer disposed on the PTC layer and comprising a conductive additive and a hot adhesive polymer.

[0009] In other features, the layers include a conductive layer disposed on the cathode current collector and comprising a conductive additive and a polymer, and a PTC layer disposed on the conductive layer and comprising a PTC material and a thermal adhesive polymer.

[0010] In other features, the layer further comprises a thermal adhesive polymer. The layer further comprises a conductive additive and a thermal adhesive polymer. The conductive additive is selected from a carbon-based conductive additive, an oxide-based conductive additive, a carbide, and a silicide. The cathode active material accounts for 70% to 99% by weight of the cathode active material layer, the conductive additive accounts for 0.5% to 20% by weight of the cathode active material layer, and the binder accounts for 0.5% to 10% by weight of the cathode active material layer.

[0011] In other features, the PTC material is doped with one or more materials selected from lanthanum (La), cesium (Ce), tin (Sb), yttrium (Y), tungsten (W), titanium (Ti), tantalum (Ta), niobium (Nb), cobalt (Co), chlorine (Cl), iodine (I) and bromine (Br). The PTC material includes at least one of BaTIO3 and a PTC material based on V2O5.

[0012] In other features, the room temperature (RT) resistance of the PTC material is less than 50 ohm-meters and the Curie temperature of the PTC material is 80° C. to 200° C. The ratio of the resistance of the PTC material at the Curie temperature divided by the resistance of the PTC material at room temperature is greater than 100.

[0013] The cathode electrode includes a multifunctional cathode current collector, the multifunctional cathode current collector including a cathode current collector made of at least one of aluminum and stainless steel and a layer comprising a positive temperature coefficient (PTC) material and a thermal adhesive polymer disposed adjacent to the cathode current collector. The cathode active material layer is disposed on the multifunctional cathode current collector and includes a cathode active material, the cathode active material comprising a nickel-containing rock salt layered oxide.

[0014] In other features, the layer includes a PTC layer including a PTC material and a polymer and a conductive layer disposed on the PTC layer and including a conductive additive and a thermal adhesive polymer. The layer includes a conductive layer including a conductive additive and a polymer and a PTC layer disposed on the conductive layer and including a PTC material and a thermal adhesive polymer. The layer also includes a conductive additive.

[0015] The present invention provides the following solutions:

[0016] Solution 1. A cathode electrode, comprising:

[0017] A multifunctional cathode current collector comprising:

[0018] a cathode current collector; and

[0019] a layer comprising a positive temperature coefficient (PTC) material disposed adjacent to said cathode current collector; and

[0020] A cathode active material layer is disposed on the multifunctional cathode current collector and comprises a cathode active material containing nickel.

[0021] Option 2. A cathode electrode according to Option 1, wherein the cathode active material comprises a nickel-containing rock salt layered oxide.

[0022] Scheme 3. The cathode electrode according to Scheme 1, wherein the cathode active material is selected from LiNi x Mn y Co 1-x-y O2、LiN x Co y Al 1-x-y O2、LiNi x Co y Mn z Al 1-x-y-z O2、LiNi x Mn y Al 1-x-y O2、LiNi x Mn 1-x O2 and LiNiO2, where x, y and z are in the range of 0 to 1.

[0023] Option 4. The cathode electrode according to Option 1, wherein the cathode current collector is made of at least one of aluminum and stainless steel.

[0024] Option 5. The cathode electrode according to Option 4, wherein the thickness of the multifunctional cathode current collector is 4 μm to 30 μm.

[0025] Option 6. The cathode electrode according to Option 1, wherein the layer comprises:

[0026] A PTC layer comprising a PTC material and a polymer disposed on the cathode current collector; and

[0027] A conductive layer is disposed on the PTC layer and includes a conductive additive and a thermal adhesive polymer.

[0028] Option 7. The cathode electrode according to Option 1, wherein the layer comprises:

[0029] a conductive layer comprising a conductive additive and a polymer disposed on the cathode current collector; and

[0030] The PTC layer is disposed on the conductive layer and includes a PTC material and a thermal adhesive polymer.

[0031] Option 8. A cathode electrode according to Option 1, wherein the layer further comprises a thermal adhesive polymer.

[0032] Option 9. The cathode electrode according to Option 1, wherein the layer further comprises a conductive additive and a thermal adhesive polymer.

[0033] Option 10. A cathode electrode according to Option 6, wherein the conductive additive is selected from carbon-based conductive additives, oxide-based conductive additives, carbides and silicides.

[0034] Option 11. A cathode electrode according to Option 1, wherein the cathode active material accounts for 70 weight % to 99 weight % of the cathode active material layer, the conductive additive accounts for 0.5 weight % to 20 weight % of the cathode active material layer, and the binder accounts for 0.5 weight % to 10 weight % of the cathode active material layer.

[0035] Option 12. A cathode electrode according to Option 11, wherein the PTC material is doped with one or more materials selected from lanthanum (La), cesium (Ce), tin (Sb), yttrium (Y), tungsten (W), titanium (Ti), tantalum (Ta), niobium (Nb), cobalt (Co), chlorine (Cl), iodine (I) and bromine (Br).

[0036] Option 13. A cathode electrode according to Option 1, wherein the PTC material comprises at least one of BaTIO3 and a V2O5-based PTC material.

[0037] Option 14. The cathode electrode according to Option 1, wherein:

[0038] The room temperature (RT) resistance of the PTC material is less than 50 ohm-meters, and

[0039] The Curie temperature of the PTC material is 80°C to 200°C.

[0040] Embodiment 15. The cathode electrode according to Embodiment 14, wherein the ratio of the resistance of the PTC material at the Curie temperature divided by the resistance of the PTC material at room temperature is greater than 100.

[0041] Embodiment 16. A cathode electrode, comprising:

[0042] A multifunctional cathode current collector comprising:

[0043] a cathode current collector made of at least one of aluminum and stainless steel; and

[0044] a layer comprising a positive temperature coefficient (PTC) material and a thermal adhesive polymer disposed adjacent to the cathode current collector; and

[0045] The cathode active material layer is disposed on the multifunctional cathode current collector and comprises a cathode active material, wherein the cathode active material comprises a nickel-containing rock salt layered oxide.

[0046] Embodiment 17. The cathode electrode according to embodiment 16, wherein the layer comprises:

[0047] A PTC layer comprising a PTC material and a polymer; and

[0048] A conductive layer is disposed on the PTC layer and includes a conductive additive and a thermal adhesive polymer.

[0049] Embodiment 18. The cathode electrode according to embodiment 16, wherein the layer comprises:

[0050] a conductive layer comprising a conductive additive and a polymer; and

[0051] A PTC layer is disposed on the conductive layer and includes a PTC material and a thermal adhesive polymer.

[0052] Option 19. A cathode electrode according to Option 16, wherein the layer further comprises a conductive additive.

[0053] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended to be illustrative only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present disclosure will be more fully understood through the detailed description and accompanying drawings, in which:

[0055] Figure 1 is a side cross-sectional view of an example of a battery cell according to the present disclosure, the battery cell including a cathode electrode having a nickel-rich cathode active material and a multifunctional cathode current collector, an anode electrode, and a separator disposed in a battery cell housing;

[0056] Figures 2 to 5 is a side cross-sectional view of an example of a multifunctional cathode current collector according to the present disclosure;

[0057] Figure 6 is a graph illustrating the change in resistance of a positive temperature coefficient (PTC) material of a multifunctional cathode current collector according to the present disclosure as a function of temperature;

[0058] Figure 7 is a flow chart of a method for manufacturing a multifunctional cathode current collector and a cathode electrode including the multifunctional cathode current collector according to the present disclosure; and

[0059] Figures 8 to 10 is a graph illustrating voltage versus capacity of a conventional battery cell and a battery cell including a cathode electrode having a multifunctional cathode current collector according to the present disclosure.

[0060] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0061] Although battery cells according to the present disclosure are shown in the context of an electric vehicle, the battery cells may be used in stationary applications and / or other applications.

[0062] As described above, the battery cell includes a cathode electrode, an anode electrode, and a separator arranged in a housing. The cathode electrode includes a cathode active material layer (including a cathode active material) arranged on a cathode current collector. In some examples, the cathode active material layer includes a nickel-rich (Ni-rich) cathode active material. Nickel-rich cathode active materials such as NCMA, NCA, and NMC811 are thermally stable because they decompose below 300°C and produce molecular oxygen (O2). When O2 is released, it reacts with flammable battery contents and increases the likelihood of thermal events such as thermal runaway.

[0063] The present disclosure relates to a cathode electrode including a multifunctional cathode current collector and a nickel-rich cathode active material. The multifunctional cathode current collector comprises a conductive filler (e.g., carbon black), a polymer, a thermal 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, wherein the cathode active material comprises a nickel-rich cathode material and a polytetrafluoroethylene (PTFE) adhesive. The multifunctional current collector increases the resistance of the cathode current collector by about 5x10 at 100°C compared to the resistance of the cathode current collector at a lower temperature (e.g., 36°C). 5 The increased resistance blocks the electron flow path from the cathode active material layer to the cathode current collector to enhance thermal stability without sacrificing electrochemical performance at lower temperatures (eg, normal operating temperature).

[0064] Reference now Figure 1 The battery cell 10 includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a predetermined order in a battery stack 12, and the battery stack 12 is located in a housing 50 that may include an electrolyte, wherein C, S, and A are integers greater than zero. The C cathode electrodes 20-1, 20-2, ..., and 20-C include a cathode active material layer 24 arranged on one or both sides of a multifunctional cathode current collector 26. The cathode active material layer 24 includes a nickel-rich cathode active material.

[0065] A anode electrodes 40-1, 40-2, ... and 40-A include an anode active material layer 42 disposed on one or both sides of an anode current collector 46. In some examples, the anode active material layer 42 and / or the cathode active material layer 24 are free-standing electrodes that are disposed adjacent to (or attached to) the multifunctional cathode current collector 26 and / or the anode current collector 46, respectively. In some examples, the anode active material layer 42 and / or the cathode active material layer 24 include a coating or a free-standing film that includes one or more active materials, one or more conductive fillers / additives, and / or one or more binder materials applied to the current collector.

[0066] In some examples, the multifunctional cathode current collector 26 and the anode current collector 46 include metal foil, metal mesh, perforated metal, 3D (3D) metal foam and / or porous metal mesh. In some examples, the anode current collector 46 is made of one or more materials selected from copper, stainless steel, brass, bronze, zinc, aluminum and / or its alloys. In some examples, the multifunctional cathode current collector 26 is made of one or more materials selected from stainless steel and aluminum. In some examples, the cathode current collector 26 has a thickness of 4 μm to 30 μm. In some examples, the cathode current collector 26 has a thickness of 6 μm to 20 μm. External tabs 28 and 48 are respectively connected to the current collectors of the cathode electrode and the anode electrode, and can be arranged on the same side or opposite sides of the battery stack 12. External tabs 28 and 48 are connected to the terminals of the battery cells.

[0067] Reference now Figures 2 to 5 , various examples of multifunctional cathode current collector 26 are shown. Figure 2In the embodiment, the multifunctional cathode current collector 26 includes a positive temperature coefficient (PTC) layer 112, which includes a PTC material 114 and a polymer 116 (e.g., polyacrylic acid (PAA) or polyethylene-ethylene vinyl acetate (PE-EVA)) arranged on one or both sides of a cathode current collector 118. The cathode current collector 118 is made of one or more materials selected from stainless steel, aluminum and / or other suitable materials. The conductive layer 122 is arranged on the PTC layer 112 and includes a conductive filler 124 and a thermal adhesive polymer 126 (e.g., PE-EVA).

[0068] exist Figure 3 In the embodiment, a conductive layer 127 including a conductive filler 124 and a polymer 116 is disposed on one or both surfaces of a cathode current collector 118. A PTC layer 129 including a PTC material 114 and a thermal adhesive polymer 126 is disposed on one or both surfaces of the conductive layer 127.

[0069] exist Figure 4 In the embodiment of the present invention, a single layer is used and the conductive filler 124 is omitted. The PTC layer 131 including the PTC material 114 and the thermal adhesive polymer 126 is disposed on one or both surfaces of the cathode current collector 118 .

[0070] exist Figure 5 In the embodiment, the mixed layer 132 is disposed on one or both surfaces of the cathode current collector 118. The mixed layer 132 includes the PTC material 114, the conductive filler 124 and the thermal adhesive polymer 126 (eg, PE-EVA). The thermal adhesive polymer provides a strong mechanical connection between the cathode current collector and the cathode active material layer.

[0071] exist Figures 2 to 5 In the cathode electrode in the embodiment of the present invention, as the operating temperature increases to a predetermined temperature (eg, 150° C.), the resistance of the PTC layer increases significantly. The increase in resistance reduces the current and improves thermal stability.

[0072] In other examples, wet coating is used to make the cathode electrode, and the thermal adhesive polymer (used to provide adhesion to the self-supporting film) is omitted. In other words, the outermost layer of the multifunctional cathode current collector does not include a thermal adhesive polymer, and the cathode active material layer is cast on the cathode current collector. For example, the cathode active material (e.g., NCMA), the binder (e.g., polyvinylidene fluoride (PVDF)) and the optional conductive additive are mixed with a solvent, cast onto the multifunctional cathode current collector, and dried.

[0073] Reference now Figure 6The graph shows the change in resistance of a positive temperature coefficient material such as barium titanate (BaTiO3) with temperature. When the temperature increases from the typical operating temperature (e.g., 36°C) to a higher temperature (e.g., 100°C), the resistance increases by about 10 5 of magnitude.

[0074] Reference now Figure 7 , showing the manufacturing Figure 5 Flowchart of a method for a multifunctional cathode current collector and a cathode electrode including a multifunctional cathode current collector. At 254, a thermal adhesive polymer, a conductive additive, and a PTC material are mixed to produce a slurry. At 258, the slurry is cast or printed (e.g., gravure printing) onto the cathode current collector and dried. At 262, the process is optionally repeated on the opposite side of the cathode current collector. At 266, a self-supporting or cast cathode active material layer is arranged or cast on one or both sides of the multifunctional cathode current collector. At 270, the layers are optionally pressed and / or heated. In some instances, the layer is heated to above the melting temperature of the thermal adhesive polymer. The thermal adhesive polymer provides a strong bond between the current collector and the self-supporting film (including the nickel-rich cathode active material layer).

[0075] Reference now Figures 8 to 10 , a graph illustrates the variation of voltage with capacity for a conventional battery cell and a battery cell including a cathode electrode with a multifunctional cathode current collector. In general, conventional battery cells and battery cells including a cathode electrode with a multifunctional cathode current collector have similar performance at normal operating temperatures. However, the cathode electrode with a multifunctional cathode current collector has the additional advantage of thermal runaway protection. When the operating temperature increases, the resistance of the path to the cathode current collector increases, thereby reducing the current.

[0076] exist Figure 8 In the embodiment, a conventional battery cell (denoted by 310) and a battery cell (denoted by 320) including a cathode electrode having a multifunctional cathode current collector have similar first cycle performance (e.g., NCMA electrode in a half-button cell at C / 20 and 25°C). The cathode active material layer comprises NCMA as a cathode active material, Super P as a conductive additive, and PTFE as a binder in a mass ratio of 96:2:2, respectively. Charging is performed using constant current constant voltage (CCCV) charging at C / 20 with a C / 100 taper. Discharge is C / 20, and the voltage range is 2.7V to 4.2V.

[0077] The cathode electrode has approximately the same performance. Conventional battery cell 310 has 5.76 mAh / cm 2 The charge capacity load is 4.99 mAh / cm 2The battery cell including the cathode electrode with the multifunctional cathode current collector has a discharge capacity load of 5.71 mAh / cm 2 The charge capacity load is 4.95 mAh / cm 2 The discharge capacity load and the Coulomb efficiency of 86.7% were achieved.

[0078] exist Fig. 9 and Fig.10 , charging rate tests of a conventional battery cell at 310 and a battery cell including a cathode electrode having a multifunctional cathode current collector at 320 at 1C and 25°C and at 2C and 25°C are shown. The cathode active material layer comprises NCMA as a cathode active material, Super P as a conductive additive, and PTFE as a binder in a mass ratio of 96:2:2, respectively. Charging is performed using constant current constant voltage (CCCV) charging at 1C with a C / 20 taper. The voltage range is 2.7V to 4.2V. The conventional cathode and the cathode electrode having a multifunctional cathode current collector have comparable charging rate performance.

[0079] In some instances, for example Figure 2 and Figure 3 In those examples, the PTC layer comprises 3 wt % to 40 wt % of a polymer and 10 wt % to 97 wt % of a PTC material. In other examples, the PTC layer comprises 5 wt % to 15 wt % of a polymer and 40 wt % to 85 wt % of a PTC material. The polymer includes a thermal adhesive polymer (e.g., polyacrylic acid (PAA), styrene-butadiene rubber (SBR), PAA-lEA). In some examples, the PTC layer has a thickness of 0.5 μm to 10 μm. In some examples, the PTC layer has a thickness of 1.0 μm to 3 μm.

[0080] In some instances, for example Figure 4 In those examples, the mixed layer comprises 10 wt % to 40 wt % of the thermal adhesive polymer, 5 wt % to 30 wt % of the PTC material, and 30 wt % to 70 wt % of the conductive additive. In other examples, the mixed layer comprises 20 wt % to 30 wt % of the thermal adhesive polymer, 10 wt % to 20 wt % of the PTC material, and 40 wt % to 60 wt % of the conductive additive. In some examples, the mixed layer has a thickness of 0.5 μm to 10 μm. In some examples, the mixed layer has a thickness of 1.0 μm to 3 μm.

[0081] In some examples, the conductive additive is selected from carbon-based conductive additives, oxide-based conductive additives, carbides and silicides. Examples of carbon-based conductive additives include carbon black, graphite, graphene, graphene oxide, SuperP, acetylene black, carbon nanofibers, carbon nanotubes and other electronic 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 La2O3. 0.75 Ca 0.25 MnO3. Examples of carbides include silicon carbide (SiC2). Examples of silicides include molybdenum disilicide (MoSi2).

[0082] In some examples, the polymer is selected from 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 includes a thermal adhesive polymer.

[0083] In some instances, the PTC material is selected from an inorganic PTC material and an organic PTC material. Examples of inorganic PTC materials include BaTIO3 and PTC materials based on V2O5. In some instances, the PTC material is doped to change the Curie temperature of the PTC material. In some instances, the dopant includes one or more materials selected from the following: (lanthanum (La), cesium (Ce), tin (Sb), yttrium (Y), tungsten (W), titanium (Ti), tantalum (Ta), niobium (Nb), cobalt (Co), chlorine (Cl), iodine (I) and / or bromine (Br)). In some instances, oxide additives such as SiO2 or Al2O3 are added.

[0084] In some examples, the Curie temperature of the PTC material is 80°C to 200°C. In some examples, the Curie temperature of the PTC material is 90°C to 120°C. In some examples, the room temperature (RT) resistance of the PTC material is less than 50 ohm-meters (ohm.m). In some examples, the room temperature (RT) resistance of the PTC material is less than 10 ohm.m. In some examples, the ratio of the resistance at the Curie temperature divided by the resistance at room temperature is greater than 100. In some examples, the ratio of the resistance at the Curie temperature divided by the resistance at room temperature is greater than 1000.

[0085] In some examples, the cathode active material accounts for 70 wt % to 99 wt % of the cathode active material layer, the conductive additive accounts for 0.5 wt % to 20 wt % of the cathode active material layer, and the binder accounts for 0.5 wt % to 10 wt % of the cathode active material layer. In some examples, the cathode active material includes a nickel-rich rock salt layered oxide. Examples of nickel-rich rock salt layered oxides include LiNi x Mn y Co 1-x-y O2(NMC)811、LiN x Co y Al 1-x-y O2(NCA), LiNi x Co y Mn z Al 1-x-y-z O2(NCMA), LiNi x Mn y Al 1-x-y O2(NMA), LiNi x Mn 1-x O2(NM) and LiNiO2(LNO).

[0086] The foregoing description is essentially only exemplary and is absolutely not intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be limited thereto, because after studying the drawings, the specification and the following claims, other modifications will become apparent. It should be understood that one or more steps in the method may be implemented in different orders (or simultaneously) without changing the principles of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more features described with respect to any embodiment of the present disclosure may be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not explicitly described. In other words, the embodiments are not mutually exclusive, and the mutual replacement of one or more embodiments is still within the scope of the present disclosure.

[0087] Various terms are used to describe the spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.), including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "on," "under," and "disposed." Unless explicitly described as "directly," when describing the relationship between a first element and a second element in the above disclosure, the relationship can be a direct relationship in which no other intervening elements exist between the first element and the second element, or an indirect relationship in which one or more intervening elements exist between the first element and the second element (spatially or functionally). The phrase "at least one of A, B, and C" as used herein should be interpreted to mean a logical (A or B or C) using a non-exclusive logical OR, and should not be interpreted to mean "at least one A, at least one B, and at least one C."

[0088] In the drawings, the direction of the arrows, as shown by arrows, generally demonstrates the flow of information (such as data or instructions) related to the diagram. For example, when component A and component B exchange various information but the information transmitted from component A to component B is related to the diagram, the arrow may point from component A to component B. Such a unidirectional arrow does not mean that no other information is transmitted from component B to component A. In addition, for the information transmitted from component A to component B, component B may send a request for the information to component A or a receipt of the information.

Claims

1. A cathode electrode, comprising: A multifunctional cathode current collector comprising: a cathode current collector; and a layer comprising a positive temperature coefficient (PTC) material disposed adjacent to said cathode current collector; and A cathode active material layer is disposed on the multifunctional cathode current collector and comprises a cathode active material containing nickel.

2. The cathode electrode according to claim 1, wherein the cathode active material comprises a nickel-containing rock salt layered oxide.

3. The cathode electrode according to claim 1, wherein the cathode active material is selected from LiNi x Mn y Co 1-x-y O2、LiN x Co y Al 1-x-y O2、LiNi x Co y Mn z Al 1-x-y-z O2、LiNi x Mn y Al 1-x-y O2、LiNi x Mn 1-x O2 and LiNiO2, where x, y and z are in the range of 0 to 1. 4 . The cathode electrode according to claim 1 , wherein the cathode current collector is made of at least one of aluminum and stainless steel. 5 . The cathode electrode according to claim 4 , wherein the multifunctional cathode current collector has a thickness of 4 μm to 30 μm.

6. The cathode electrode according to claim 1, wherein the layer comprises: A PTC layer comprising a PTC material and a polymer disposed on the cathode current collector; and A conductive layer is disposed on the PTC layer and includes a conductive additive and a thermal adhesive polymer.

7. The cathode electrode according to claim 1, wherein the layer comprises: a conductive layer comprising a conductive additive and a polymer disposed on the cathode current collector; and The PTC layer is disposed on the conductive layer and includes a PTC material and a thermal adhesive polymer.

8. The cathode electrode of claim 1, wherein the layer further comprises a thermal adhesive polymer.

9. The cathode electrode of claim 1, wherein the layer further comprises a conductive additive and a thermal adhesive polymer.

10. The cathode electrode of claim 6, wherein the conductive additive is selected from the group consisting of carbon-based conductive additives, oxide-based conductive additives, carbides, and silicides.

Images